Article

Prenatal hypoxia affected endothelium-dependent vasodilation in mesenteric arteries of aged offspring via increased oxidative stress

January 2019
Hypertension Research 42(Suppl)

Authors:

Prenatal hypoxia can affect vascular functions in young offspring. However, there is limited knowledge regarding whether and how prenatal hypoxia influences vascular functions in aged offspring. This study compared the effects of prenatal hypoxia on the mesenteric arteries (MA) between a young adult and aged offspring and investigated the underlying mechanisms. Pregnant rats were randomly divided into the control and prenatal hypoxia groups. The vascular functions and molecular levels were assessed in 5-month-old (5 M) or 20-month-old (20 M) offspring. Prenatal hypoxia decreased acetylcholine-mediated vascular relaxations in 20-M but not 5-M offspring. Sodium nitroprusside-mediated relaxation curves were not altered by prenatal hypoxia in 5- and 20-M offspring. Prenatal hypoxia enhanced the contractile responses caused by phenylephrine, phorbol 12,13-dibutyrate, and 5-hydroxytryptamine only in 5-M offspring. The endothelial NO synthase (eNOS) activities were decreased along with downregulated eNOS mRNA expression and phosphorylated eNOS/total eNOS protein expression in 20-M offspring with prenatal hypoxia. The NADPH oxidase (NOX) inhibitor apocynin and superoxide dismutase (SOD) mimetic tempol restored the acetylcholine-mediated weaker relaxations in 20-M offspring with prenatal hypoxia. Enzyme-linked immunosorbent and dihydroethidium assay showed that prenatal hypoxia enhanced oxidative stress in 20-M offspring. Transmission electron microscopy showed that prenatal hypoxia damaged mitochondrial structures in the MA endothelial cells of 20-M offspring. Increased NOX2 protein expression and decreased SOD3 expression were found in 20-M offspring. The results demonstrated that endothelial dysfunction induced by intrauterine hypoxia occurred with aging via enhanced oxidative stress and decreased nitric oxide activities in aged offspring.

Vascular Effects of Perinatal Hypoxia in the Early Postnatal Period in Rats

Article

May 2023
Fiziol Z Im M Sechenova

The normal functioning of the vascular system in early ontogenesis can be altered by adverse effects affecting the organism of the fetus / newborn during pregnancy, during or after childbirth. However, at the moment there is not enough data on the “acute” (immediately after exposure) and “delayed” (after several days) effects of short-term (within several hours) perinatal normobaric hypoxia on the functioning of the peripheral vascular system of the systemic circulation in early ontogenesis in mammals. The aim of this work was to study the “acute” and “delayed” effects of a single normobaric hypoxia on the functioning of the arteries of the systemic circulation in early postnatal ontogenesis. The contractile responses of the saphenous artery of rats aged 10–14 days were studied in isometric myograph. Acute normobaric hypoxia (8% O2) was simulated for 2 hours in 10-day-old rat pups. The selected hypoxia regimen did not lead to changes in arterial contractile responses to the α1-adrenergic agonist methoxamine either immediately after exposure or several days later. Endothelium-dependent relaxation of arteries to acetylcholine also did not differ between groups. Hypoxia did not change the contribution of anticontractile pathways associated with nitric oxide and Kv7 channels, as well as the pro contractile role of Rho-kinase. Thus, according to the presented results, short-term normobaric hypoxia on the 10th day of life in rat pups does not lead to either “acute” or “delayed” changes in the regulation of the tone of the peripheral arteries of the systemic circulation in the early postnatal period.

Vascular Effects of Perinatal Hypoxia in the Early Postnatal Period in Rats

Article

Jun 2023

Perinatal hypoxia weakens anticontractile influence of NO in rat arteries during early postnatal period

Article

Feb 2024

Background: Perinatal hypoxia affects a lot of neonates worldwide every year, however its effects on the functioning of systemic circulation are not clear yet. We aimed at investigation the effects of perinatal hypoxia on the second day of life on the functioning of the rat systemic vasculature in early postnatal period. Methods: 2-day-old male rat pups were exposed to normobaric hypoxia (8% O2, 92% N2) for 2 hours. At the 11-14 days cutaneous (saphenous) arteries were isolated and studied by wire myography and Western blotting. Results: Hypoxia weakened the contribution of anticontractile influence of NO, but did not affect the contribution of Rho-kinase or Kv7 channels to the contraction to α1-adrenergic agonist methoxamine. The content of eNOS and protein kinase G were not altered by hypoxic conditions. Conclusion: Perinatal hypoxia in rats at the second day of life leads to the decrease of anticontractile effect of NO in the systemic arteries in early postnatal ontogenesis (at the age of 11-14 days). Decreased anticontractile effect of NO can be the reason for insufficient blood supply and represent a risk factor for the development of cardiovascular disorders. Impact: The mechanisms of perinatal hypoxia influences on systemic circulation are almost unknown. We have shown that perinatal hypoxia weakens anticontractile influence of nitric oxide in early postnatal period. The influence of perinatal hypoxia on systemic circulation should be taken into account during treatment of newborns suffered from the lack of oxygen.

Gestational Hypoxia Impaired Endothelial Nitric Oxide Synthesis Via miR-155-5p/NADPH Oxidase/Reactive Oxygen Species Axis in Male Offspring Vessels

Article

Full-text available

Jan 2024

Background Nitric oxide (NO) is the most important vasodilator secreted by vascular endothelial cells, and its abnormal synthesis is involved in the development of cardiovascular disease. The prenatal period is a critical time for development and largely determines lifelong vascular health in offspring. Given the high incidence and severity of gestational hypoxia in mid‐late pregnancy, it is urgent to further explore whether it affects the long‐term synthesis of NO in offspring vascular endothelial cells. Methods and Results Pregnant Sprague–Dawley rats were housed in a normoxic or hypoxic (10.5% O 2 ) chamber from gestation days 10 to 20. The thoracic aortas of fetal and adult male offspring were isolated for experiments. Gestational hypoxia significantly reduces the NO‐dependent vasodilation mediated by acetylcholine in both the fetal and adult offspring thoracic aorta rings. Meanwhile, acetylcholine‐induced NO synthesis is impaired in vascular endothelial cells from hypoxic offspring thoracic aortas. We demonstrate that gestational hypoxic offspring exhibit a reduced endothelial NO synthesis capacity, primarily due to increased expression of NADPH oxidase 2 and enhanced reactive oxygen species. Additionally, gestational hypoxic offspring show elevated levels of miR‐155‐5p in vascular endothelial cells, which is associated with increased expression of NADPH oxidase 2 and reactive oxygen species generation, as well as impaired NO synthesis. Conclusions The present study is the first to demonstrate that gestational hypoxia impairs endothelial NO synthesis via the miR‐155‐5p/NADPH oxidase 2/reactive oxygen species axis in offspring vessels. These novel findings indicate that the detrimental effects of gestational hypoxia on fetal vascular function can persist into adulthood, providing new insights into the development of vascular diseases.

Role of Reactive Oxygen Species in Aging and Age-Related Diseases: A Review

Article

Aug 2022

Research on the role of reactive oxygen species (ROS) in the aging process has advanced significantly over the last two decades. In light of recent findings, ROS takes part in the aging process of cells along with contributing to various physiological signaling pathways. Antioxidants being cells' natural defense mechanism against ROS-mediated alteration, play an imperative role to maintain intracellular ROS homeostasis. Although the complete understanding of the ROS regulated aging process is yet to be fully comprehended, current insights into various sources of cellular ROS and their correlation with the aging process and age-related diseases are portrayed in this review. In addition, results on the effect of antioxidants on ROS homeostasis and the aging process as well as their advances in clinical trials are also discussed in detail. The future perspective in ROS-antioxidant dynamics on antiaging research is also marshaled to provide future directions for ROS-mediated antiaging research fields.

Prenatal Hypoxia Affects Foetal Cardiovascular Regulatory Mechanisms in a Sex- and Circadian-Dependent Manner: A Review

Article

Full-text available

Mar 2022
INT J MOL SCI

Prenatal hypoxia during the prenatal period can interfere with the developmental trajectory and lead to developing hypertension in adulthood. Prenatal hypoxia is often associated with intrauterine growth restriction that interferes with metabolism and can lead to multilevel changes. Therefore, we analysed the effects of prenatal hypoxia predominantly not associated with intrauterine growth restriction using publications up to September 2021. We focused on: (1) The response of cardiovascular regulatory mechanisms, such as the chemoreflex, adenosine, nitric oxide, and angiotensin II on prenatal hypoxia. (2) The role of the placenta in causing and attenuating the effects of hypoxia. (3) Environmental conditions and the mother’s health contribution to the development of prenatal hypoxia. (4) The sex-dependent effects of prenatal hypoxia on cardiovascular regulatory mechanisms and the connection between hypoxia-inducible factors and circadian variability. We identified that the possible relationship between the effects of prenatal hypoxia on the cardiovascular regulatory mechanism may vary depending on circadian variability and phase of the days. In summary, even short-term prenatal hypoxia significantly affects cardiovascular regulatory mechanisms and programs hypertension in adulthood, while prenatal programming effects are not only dependent on the critical period, and sensitivity can change within circadian oscillations.

Гистоморфометрическое сравнение макрососудов плаценты при преэклампсии и нормотензивной беременности

Article

Full-text available

Dec 2024

Актуальность: На сегодняшний день морфометрические исследования сосудов плаценты демонстрируют различные структурные изменения сосудистой сети ворсинчатого дерева плаценты при преэклампсии в сравнении с нормальной беременностью, которые подчеркивают необходимость исследований изменений сосудистой сети плаценты при преэклампсии с применением стандартизированных методов морфометрического анализа.Цель исследования – выявление ассоциации плацентарной ангиопатии при нормотензивной беременности и беременности, осложненной преэклампсией.Материалы и методы: В исследование были включены плаценты от одноплодных беременностей, осложненных преэклампсией, у женщин, родоразрешенных в медицинских организациях г. Караганды (Казахстан). Плаценты разделили на две группы: группа преэклампсии (n = 59) и контрольная группа (n = 70), которые были сопоставимы по сроку гестации. Исследование плаценты и отбор фрагментов плацентарной ткани проводились в соответствии с консенсусными рекомендациями Amsterdam Placental Workshop Group. Срезы окрашивали гематоксилином и эозином и трихромом Массона. Морфометрические измерения проводили с помощью программного обеспечения ImageJ.Результаты: Наши данные показали в группе преэклампсии значительное уменьшение толщины стенки проксимальных и дистальных сосудов с увеличением внутреннего диаметра в сравнении с контрольной группой (p<0,01).Заключение: Выявлено два гистопаттерна макрососудов плаценты при преэклампсии: гистофенотип диффузной (проксимальной и дистальной) эктатической макроангиопатии с тонкой стенкой сосудов с уменьшением толщины мышечного слоя и гистофенотип проксимального фибромускулярного склероза с сосудистой облитерацией/спазмом и дистальной эктатической макроангиопатией. Мы полагаем, что значительные структурные различия ремоделирования сосудов могут отражать различный временно-пространственный характер действия патологического фактора. Будущие исследования необходимы для изучения влияния материнской коморбидности на сосудистые изменения в плаценте.

Placental Macrovascular Pattern from Pregnancies with Maternal Hypertensive and Fetal Growth Capacity Complications

Article

Full-text available

Dec 2024

Histomorphometric measurements of the wall thickness and internal diameter of the macrovessels of the chorionic villi of placentas from pregnancies complicated by preeclampsia or fetal growth restriction in comparison with normotensive pregnancy. Methods: The research included placentas from singleton pregnancies complicated by preeclampsia and/or fetal growth restriction, women delivered in medical institutions in Karaganda city (Kazakhstan). Placentas were divided into three groups: PE (n = 59), isolated FGR (n = 24), and PE with FGR (n = 41). The control group consisted of normotensive pregnancies, compared by gestation period. Placental examination and selection of placental tissue fragments were carried out in accordance with the consensus recommendations of the Amsterdam Placental Workshop Group. The sections were stained with hematoxylin and eosin and Masson trichrome. Morphometric measurements were performed using ImageJ software version 1.52p. Results: Our data showed that, in the PE group, there was a significant decrease in the wall thickness of the proximal and distal vessels with an increase in internal diameter compared with the control group (p < 0.01). In the PE + FGR group, there was a thickening of the wall of the proximal part of the vessels with a decrease in their lumen and a decrease in the wall thickness of the vessels with an increase in the lumen in the distal part compared with the control group (p < 0.01). Conclusions: Two histopatterns of placental macrovessels in preeclampsia were revealed: the histophenotype of diffuse (proximal and distal) ectatic macroangiopathy with a thin vascular wall with a decrease in the thickness of the muscle layer and the histophenotype of proximal fibromuscular sclerosis with vascular obliteration/spasm and distal ectatic macroangiopathy. We believe that significant structural differences in vascular remodeling may reflect the different temporal and spatial nature of the pathological factor. Future research is needed to investigate the associations between histopatterns of placental vascular remodeling in preeclampsia and long-term perinatal/maternal outcomes.

Sex-specific differences in the mechanisms for enhanced thromboxane A2-mediated vasoconstriction in adult offspring exposed to prenatal hypoxia

Article

Full-text available

Jun 2024

Background Prenatal hypoxia, a common pregnancy complication, leads to impaired cardiovascular outcomes in the adult offspring. It results in impaired vasodilation in coronary and mesenteric arteries of the adult offspring, due to reduced nitric oxide (NO). Thromboxane A 2 (TxA 2 ) is a potent vasoconstrictor increased in cardiovascular diseases, but its role in the impact of prenatal hypoxia is unknown. To prevent the risk of cardiovascular disease by prenatal hypoxia, we have tested a maternal treatment using a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ). We hypothesized that prenatal hypoxia enhances vascular TxA 2 responses in the adult offspring, due to decreased NO modulation, and that this might be prevented by maternal nMitoQ treatment. Methods Pregnant Sprague–Dawley rats received a single intravenous injection (100 µL) of vehicle (saline) or nMitoQ (125 µmol/L) on gestational day (GD)15 and were exposed to normoxia (21% O 2 ) or hypoxia (11% O 2 ) from GD15 to GD21 (term = 22 days). Coronary and mesenteric arteries were isolated from the 4-month-old female and male offspring, and vasoconstriction responses to U46619 (TxA 2 analog) were evaluated using wire myography. In mesenteric arteries, L-NAME (pan-NO synthase (NOS) inhibitor) was used to assess NO modulation. Mesenteric artery endothelial (e)NOS, and TxA 2 receptor expression, superoxide, and 3-nitrotyrosine levels were assessed by immunofluorescence. Results Prenatal hypoxia resulted in increased U46619 responsiveness in coronary and mesenteric arteries of the female offspring, and to a lesser extent in the male offspring, which was prevented by nMitoQ. In females, there was a reduced impact of L-NAME in mesenteric arteries of the prenatal hypoxia saline-treated females, and reduced 3-nitrotyrosine levels. In males, L-NAME increased U46619 responses in mesenteric artery to a similar extent, but TxA 2 receptor expression was increased by prenatal hypoxia. There were no changes in eNOS or superoxide levels. Conclusions Prenatal hypoxia increased TxA 2 vasoconstrictor capacity in the adult offspring in a sex-specific manner, via reduced NO modulation in females and increased TP expression in males. Maternal placental antioxidant treatment prevented the impact of prenatal hypoxia. These findings increase our understanding of how complicated pregnancies can lead to a sex difference in the programming of cardiovascular disease in the adult offspring. Graphical Abstract

In vitro fertilization with frozen embryo transfer increased histamine-mediated contractile sensitivity via PKCβ in human umbilical vein

Article

Full-text available

Jun 2023
REPROD BIOL ENDOCRIN

Objective In vitro fertilization-embryo transfer (IVF-ET) technologies (especially frozen ET) have been widely used, which might affect maternal and fetal health. Information regarding influence of IVF-ET on the vasoconstriction of human umbilical vein (HUV) is limited. This study determined effects of frozen ET on histamine-mediated vascular responses in HUV and related mechanisms. Methods and results HUVs were collected from frozen ET conceived pregnancy and spontaneously conceived pregnancy (control). Histamine concentration in umbilical plasma was higher in frozen ET group than the control. Histamine-mediated contractile response curve was left-shifted in the frozen ET group when comparing with the control. In isolated HUV rings, H1R showed a critical role in regulating vascular constriction, while H2R played little roles in regulating vessel tone. Iberiotoxin and 4-aminopyridine didn’t significantly change histamine-mediated constriction in HUVs. Histamine-induced vasoconstrictions were significantly decreased by nifedipine, KN93, or GF109203X, while the inhibitory effects were significantly greater in the frozen ET group in comparison to the control. The constrictions by Bay K8644, phenylephrine, or PDBu were stronger in frozen ET, respectively. There was a decrease in the protein expressions of H1R and H2R, an increase in protein expressions of BKCaα and PKCβ. Conclusions Histamine-induced constriction in HUV was mainly via H1R. The increased sensitivity to histamine in HUV following frozen ET cycles were linked to the enhanced PKCβ protein expression and function. The new data and findings in this study provide important insight into influences of frozen ET on fetal vessel development and potential influence in long-term.

The biochemical estimation of the nitric oxide system in prenatally stressed rats

Article

Sep 2021

Introduction. Pregnancy development following unfavorable conditions could facilitate disorders of nitric oxide (NO) production during offspring’s postnatal life and «program» offspring’s cardiovascular diseases. Investigation of particular features and mechanisms of nitric oxide synthesis and action disorders following prenatal stress will promote expansion of considerations about pathogenesis of different cardiovascular diseases and propose new approaches to their prevention and management. The aim of the investigation is to assess the nature of nitric oxide synthesis and action in mature rats whose mothers were exposed to chronic «unpredictable» stress during pregnancy. Materials and methods. Pregnant rats were subdivided into the «control» and «stress» groups (in 20 animals). The rats from the «stress» group were exposed to multiple different stressors at various intervals, such as 1-day famine; 20-min. immobilization in the water at room temperature; 1-day contact with cats’ excrements. In the blood serum of 3-mo offspring (n=96, including «control» males – 24, «control» females – 26, «stress» males – 22, «stress» females – 24) concentration of the stable products of NO degradation – nitrates/nitrites (NO 3 – /NO 2 – ), endothelial (eNOS) and inducible (iNOS) isoforms of the NO-synthase, inhibitor of NO-synthase asymmetric dimethylargininne (ADMA), cyclic guanosine monophosphate (cGMP), lipid peroxidation products – diene conjugates (DC) and malonic dialdehyde (MDA) and C-reactive protein ( hs CRP) was detected. Results . The decrease of eNOS and cGMP concentration (by 12.9 and 31.9 %, respectively), increase of iNOS, hs CRP and ADMA concentration (by 49.9, 20.3 и 63.1 %, respectively) without statistically significant fluctuation in the NO 3 – /NO 2 – level and accumulation of DC and MDA by 21.1 % and 1.5 times in a prenatally stressed male rats’ blood serum were found (as compared with «control» male rats). In a blood serum of female rats, whose mothers were exposed to chronic «unpredictable» stress during pregnancy, a tendency to eNOS concentration decreasing, and increase of iNOS by 30.6 %, hs CRP by 23.9 % and MDA by 2.3 times without statistically significant changes in cGMP, ADMA, NO 3 – /NO 2 – , and DC concentration were detected (as compared with «control» female rats). Conclusion. Identified changes of the nitric oxide system synthesis and action in the prenatally stressed male rats could argue the high risk of their cardiovascular system lesion.

Melatonin ameliorates hypertension in hypertensive pregnant mice and suppresses the hypertension-induced decrease in Ca2+-activated K+ channels in uterine arteries

Article

Jun 2021

Decreased secretion of melatonin was reported to be associated with an enhanced risk of hypertension and diabetes. However, the effect of melatonin on gestational hypertension (GH) and the underlying mechanism remain unclear. A GH mouse model was established via electrical stimulation. The hypertensive phenotypes were indicated by systolic blood pressure (SBP) and urinary protein levels. Uterine artery (UtA) endothelial function was detected by relaxation, peak systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). Protein expression levels were determined using immunochemistry and Western blots. Pregnancy outcomes were indicated by the fetal live ratio, fetal weight and placental weight. Melatonin supplementation ameliorated hypertensive phenotypes in the mice with GH and enhanced UtA endothelial response to acetylcholine. The BKCa potassium channel was involved in the effect of melatonin on UtA endothelial function, and melatonin promoted BKCa potassium channel expression and function in UtAs. Finally, melatonin improved pregnancy outcomes in pregnant mice. In conclusion, melatonin ameliorates hypertension in hypertensive pregnant mice and suppresses hypertension-induced decreases in Ca²⁺-activated K⁺ channels in uterine arteries.

Management of oxidative stress and inflammation in cardiovascular diseases: mechanisms and challenges

Article

Full-text available

Jul 2021
ENVIRON SCI POLLUT R

Cardiovascular diseases (CVDs) have diverse physiopathological mechanisms with interconnected oxidative stress and inflammation as one of the common etiologies which result in the onset and development of atherosclerotic plaques. In this review, we illustrate this strong crosstalk between oxidative stress, inflammation, and CVD. Also, mitochondrial functions underlying this crosstalk, and various approaches for the prevention of redox/inflammatory biological impacts will be illustrated. In part, we focus on the laboratory biomarkers and physiological tests for the evaluation of oxidative stress status and inflammatory processes. The impact of a healthy lifestyle on CVD onset and development is displayed as well. Furthermore, the differences in oxidative stress and inflammation are related to genetic susceptibility to cardiovascular diseases and the variability in the assessment of CVDs risk between individuals; Omics technologies for measuring oxidative stress and inflammation will be explored. Finally, we display the oxidative stress-related microRNA and the functions of the redox basis of epigenetic modifications.

Hierro, Insulina y Cardiopatía Coronaria Énfasis en la Generación de Muerte Súbita y Diabetes Oculta El porqué Donar Sangre Reduce el Riesgo de Muerte Cardiovascular

Book

Full-text available

Jan 2021

Enero, 2019 RESUMEN El Hierro es esencial para la vida, pero su exceso libre o acumulado es un tóxico celular, puesto que es el metal que menos se elimina en el humano. Es un potente creador de radicales libres que genera /incrementa significativamente el estrés oxidativo. La sobrecarga de hierro incrementa el riesgo de enfermedad cardiovascular en la población general, particularmente en varones y en mujeres en edad fértil no hispanas (Ramakrishnan, 2002). El hierro influencia el metabolismo de la glucosa, inclusive en ausencia de sobrecargas elevadas; incrementa el daño cardiovascular pre-existente, y su reducción alivia la patología cardiaca coronaria y reducir o prevenir sus complicaciones. Ciertamente, elevados niveles de hierro catalítico y/o acumulado como ferritina aumenta el riesgo para el desarrollo de aterosclerosis coronaria. Confirmando ello, se ha reportado una correlación directa entre la aterosclerosis asintomática en sujetos sanos (medido por el índice intima-media thickness de la carótida común) con los depósitos de hierro (relación plasmática receptor de transferrina /ferritina) (Syrovatka, 2011).

Prenatal hypoxia increases blood pressure in male rat offspring and affects their response to artificial light at night

Article

Full-text available

Oct 2020

Prenatal hypoxia (PH) has negative consequences on the cardiovascular system in adulthood and can affect the responses to additional insults later in life. We explored the effects of PH imposed during embryonic day 20 (10.5% O 2 for 12 h) on circadian rhythms of systolic blood pressure (BP) and heart rate (HR) in mature male rat offspring measured by telemetry. We evaluated: (1) stability of BP and HR changes after PH; (2) circadian variability of BP and HR after 2 and 5 weeks of exposure to artificial light at night (ALAN; 1–2 lx); and (3) response of BP and HR to norepinephrine. PH increased BP in the dark (134 ± 2 mmHg vs. control 127 ± 2 mmHg; p = 0.05) and marginally in the light (125 ± 1 mmHg vs. control 120 ± 2 mmHg) phase of the day but not HR. The effect of PH was highly repeatable between 21- and 27-week-old PH male offspring. Two weeks of ALAN decreased the circadian variability of HR ( p < 0.05) and BP more in control than PH rats. After 5 weeks of ALAN, the circadian variability of HR and BP were damped compared to LD and did not differ between control and PH rats ( p < 0.05). Responses of BP and HR to norepinephrine did not differ between control and PH rats. Hypoxia at the end of the embryonic period increases BP and affects the functioning of the cardiovascular system in mature male offspring. ALAN in adulthood decreased the circadian variability of cardiovascular parameters, more in control than PH rats.

Prenatal Hypoxia and Placental Oxidative Stress: Insights from Animal Models to Clinical Evidences

Article

Full-text available

May 2020

Hypoxia is a common form of intrauterine stress characterized by exposure to low oxygen concentrations. Gestational hypoxia is associated with the generation of reactive oxygen species. Increase in oxidative stress is responsible for damage to proteins, lipids and DNA with consequent impairment of normal cellular functions. The purpose of this review is to propose a summary of preclinical and clinical evidences designed to outline the correlation between fetal hypoxia and oxidative stress. The results of the studies described show that increases of oxidative stress in the placenta is responsible for changes in fetal development. Specifically, oxidative stress plays a key role in vascular, cardiac and neurological disease and reproductive function dysfunctions. Moreover, the different finding suggests that the prenatal hypoxia-induced oxidative stress is associated with pregnancy complications, responsible for changes in fetal programming. In this way, fetal hypoxia predisposes the offspring to congenital anomalies and chronic diseases in future life. Several antioxidant agents, such as melatonin, erythropoietin, vitamin C, resveratrol and hydrogen, shown potential protective effects in prenatal hypoxia. However, future investigations will be needed to allow the implementation of these antioxidants in clinical practice for the promotion of health in early intrauterine life, in fetuses and children.

Exposure to prenatal hypoxia impairs the function and structure of the carotid arteries in the adult offspring

Article

Jan 2025
AM J PHYSIOL-HEART C

Prenatal hypoxia, a common pregnancy complication, can lead to vascular dysfunction, thereby increasing the risk of cardiovascular disease in the adult offspring. Carotid arteries are responsible for the majority of the blood flow to the brain/head, and carotid artery dysfunction is associated with life-threating cardiovascular events, such as stroke. However, whether prenatal hypoxia exposure impacts the function of the carotid arteries in the adult offspring is not known. We hypothesize that prenatal hypoxia impairs carotid artery function in the adult male and female offspring. Sprague Dawley rats were exposed to normoxia (21% O 2 ) or hypoxia (11% O 2 ) from gestational day (GD) 15 to 21 (term=22 days; n=9-11/group). Carotid arteries were isolated from the 4-month-old adult male and female offspring. Vasoconstrictor and vasodilatory properties were assessed by wire myography, and biomechanical properties (myogenic tone, circumferential stress and strain) by pressure myography. Collagen deposition (Masson’s trichrome stain) and elastin density (Verhoeff stain) were measured in carotid artery cryosections. Prenatal hypoxia did not impact vasoconstriction or vasorelaxation responses in carotid arteries from both offspring. However, in males, prenatal hypoxia reduced carotid artery myogenic tone development and increased circumferential strain, which coincided with a lower collagen deposition and higher elastin density. In females, prenatal hypoxia tended to lower carotid artery circumferential strain (i.e., increased stiffness), without differences in myogenic tone or collagen/elastin density. Altogether, these data show that prenatal hypoxia exposure affects the carotid arteries of the adult offspring in a sex-specific manner, which may impact the blood flow regulation to the brain.

Perinatal Hypoxia Aggravates Occlusive Pulmonary Vasculopathy In SU5416/Hypoxia-Treated Rats Later In Life

Article

Jun 2022
AM J PHYSIOL-LUNG C

Pulmonary arterial hypertension (PAH) is a fatal disease, which is characterized by occlusive pulmonary vascular disease (PVD) in small pulmonary arteries. It remains unknown whether perinatal insults aggravate occlusive PVD later in life. We tested the hypothesis that perinatal hypoxia aggravates PVD and survival in rats. PVD was induced in rats with/without perinatal hypoxia (E14 to P3) by injecting SU5416 at 7 weeks of age and subsequent exposure to hypoxia for 3 weeks (SU5416/hypoxia). Hemodynamic and morphological analyses were performed in rats with/without perinatal hypoxia at 7 weeks of age (baseline rats, n=12) and at 15 weeks of age in 4 groups of rats: SU5416/hypoxia or control rats with/without perinatal hypoxia (n=40). Pulmonary artery smooth muscle cells (PASMCs) from the baseline rats with/without perinatal hypoxia were used to assess cell proliferation, inflammation and genomic DNA methylation profile. Although perinatal hypoxia alone did not affect survival, physiological or pathological parameters at baseline or at the end of the experimental period in controls, perinatal hypoxia decreased weight gain and survival rate, and increased right ventricular systolic pressure, right ventricular hypertrophy, and indices of PVD in SU5416/hypoxia rats. Perinatal hypoxia alone accelerated the proliferation and inflammation of cultured PASMCs from baseline rats, which was associated with DNA methylation. In conclusion, we established the first fatal animal model of PAH with worsening hemodynamics and occlusive PVD elicited by perinatal hypoxia, which was associated with hyperproliferative, pro-inflammatory, and epigenetic changes in cultured PASMCs. These findings provide insights into the treatment and prevention of occlusive PVD.

In utero hypoxia attenuated acetylcholine-mediated vasodilatation via CHRM3/p-NOS3 in fetal sheep MCA: role of ROS/ERK1/2

Article

May 2022

Hypoxia can lead to adult middle cerebral artery (MCA) dysfunction and increase the risk of cerebrovascular diseases. It is largely unknown whether intrauterine hypoxia affects fetal MCA vasodilatation. This study investigated the effects and mechanisms of intrauterine hypoxia on fetal MCA vasodilatation. Near-term fetal sheep were exposed to intrauterine hypoxia. Human umbilical vein endothelial cells (HUVECs) were exposed to hypoxia in cellular experiments. Vascular tone measurement, molecular analysis, and transmission electron microscope (TEM) were utilized to determine vascular functions, tissue anatomy, and molecular pathways in fetal MCA. In fetal MCA, acetylcholine (ACh) induced reliable relaxation, which was markedly attenuated by intrauterine hypoxia. Atropine, P-F-HHSiD, L-NAME, and u0126 blocked most ACh-mediated dilation, while AF-DX 116 and tropicamide partially inhibited the dilation. Indomethacin and SB203580 did not significantly change ACh-mediated dilation. Tempol and PS-341 could restore the attenuated ACh-mediated vasodilatation following intrauterine hypoxia. The mRNA expression levels of CHRM2 and CHRM3 and the protein levels of CHRM3, p-NOS3, SOD2, ERK1/2, p-ERK1/2, MAPK14, and p-MAPK14 were significantly reduced by intrauterine hypoxia. The dihydroethidium assay showed that the production of ROS was increased under intrauterine hypoxia. TEM analysis revealed endothelial cells damaged by intrauterine hypoxia. In HUVECs, hypoxia increased ROS formation and decreased the expression of CHRM3, p-NOS3, SOD1, SOD2, SOD3, ERK1/2, p-ERK1/2, and p-MAPK14, while tempol and PS-341 potentiated p-NOS3 protein expression. In conclusion, in utero hypoxia reduced ACh-mediated vasodilatation in ovine MCA predominantly via decreased CHRM3 and p-NOS3, and the decreased NOS3 bioactivities might be attributed to ROS and ERK1/2.

Sex-Specific Effects of Prenatal Hypoxia on the Cardiac Endothelin System in Adult Offspring

Article

Feb 2022

Fetal hypoxia, a major consequence of complicated pregnancies, impairs offspring cardiac tolerance to ischemia/reperfusion (I/R) insult, however, the mechanisms remain unknown. Endothelin-1 (ET-1) signaling through the endothelin A receptors (ET A ) is associated with cardiac dysfunction. We hypothesized that prenatal hypoxia exacerbates cardiac susceptibility to I/R via increased ET-1 and ET A levels, while ET A inhibition ameliorates this. Pregnant Sprague-Dawley rats were exposed to normoxia (21% O 2 ) or hypoxia (11% O 2 ) on gestational days 15-21. Offspring were aged to 4 months, and hearts were aerobically perfused or subjected to ex vivo I/R, with or without pre-infusion with an ET A antagonist (ABT-627). ET-1 levels were assessed with ELISA in aerobically perfused and post-I/R left ventricles (LV). ET A and ET B levels were assessed by Western blotting in non-perfused LV. As hypothesized, ABT-627 infusion tended to improve post-I/R recovery in hypoxic females (p=0.0528), however, surprisingly, ABT-627 prevented post-I/R recovery only in the hypoxic males (p<0.001). ET-1 levels were increased in post-I/R LV in both sexes regardless of the prenatal exposure (p<0.01). ET A expression was similar among all groups, while ET B (isoform C) levels were decreased in prenatally hypoxic females (p<0.05). In prenatally hypoxic males, ET A signaling may be essential for tolerance to I/R, while in prenatally hypoxic females, ET A may contribute to cardiac dysfunction. Our data illustrate that understanding the prenatal history has critical implications for treatment strategies in adult chronic diseases.

The Role of Reactive Oxygen Species in the Tone Regulation of Respiratory and Locomotor Muscle Arteries of the Rat

Article

Jul 2021

Iron, Insulin and Coronary Heart Disease Emphasis on the Generation of Sudden Death and Occult Diabetes (And Why Donating Blood Can Reduce Cardiovascular Death)

Article

Full-text available

Mar 2020

Juan ARIEL Jara Guerrero

Dysregulated glucose metabolism promote inflammation in monocytes and macrophages from patients with atherosclerotic coronary artery disease. Men with metabolic syndrome are at increased risk for sudden cardiac death, and the incident sudden death is not explained by obesity or traditional cardiovascular risk factors (Kurl, 2016), but the ingested nutritional iron. Individuals with increased abdominal adiposity exhibit an increased risk of heart failure, in spite of there are oweweigtht or not (Cavalera, 2014), because the insulin resistance contribute to increased myocardial fibrosis in the absence of hypertension (Quilliot, 2005). Iron overload, and plasma viscosity contributes to cardiovascular risk in the general population, particularly in men (Van der A, 2005; Junker, 1998). Iron influences glucose metabolism, even in the absence of significant iron overload, and its reduction may alleviate coronary heart disease and reduced or prevent their complications: High stored or free iron levels (measured by serum ferritin or catalytic iron concentrations) elevate risk for development of coronary atherosclerosis, because labile iron accelerates endothelial dysfunction and originates oxidative injury that promotes systemic and vascular inflammation, phrothrombotic conditions and insulin resistance (Williams, 2002). High serum ferritin is strongly and independently associated with acute myocardial infarction and constitutes a novel risk factor in acute sudden event (Holay, 2012). Iron plays a direct and causal role in diabetes pathogenesis mediated both by β-cell failure and insulin resistance (Simcox, 2013). In the general population, body iron stores are positively associated with the development of glucose intolerance, type 2 diabetes and gestational diabetes. In this way, blood donation significant drops in the incidence of cardiovascular events, as well as in procedures such as percutaneous transluminal coronary angioplasty and coronary artery bypass grafting (Holsworth, 2013): frequent blood donations decreased iron stores in healthy volunteers, improving insulin sensitivity and hemodynamic parameters. Iron and oxygen-derived free radicals are important in the pathogenesis of postischemic reperfusion injury and contributes substantially to endothelial dysfunction in acute coronary syndromes (Chekanov, 2002; Duffy, 2001) , and a high iron diet potentially increase ischemic damage induced by transient ischemia and early reperfusion (García-Yébenes, 2012) in animals and humans. Iron, hyperinsulinemia, and hyperglycemia act in concert to up regulate free-radical reactions (Facchini, 2000) and this metal excess accelerated the development of atherosclerosis and its accumulation may promotes illness, particularly, ischemic cardiovascular diseases. Insulin resistance in macrophages promotes formation of a necrotic core in atherosclerotic plaques by enhancing macrophage apoptosis, and exposure it to circulating blood in the event of plaque rupture can precipitate thrombosis, leading to unstable angina pectoris, myocardial infarction and sudden death (Rask.Madsen, 2012, rev). In humans phlebotomy slows progression of peripheral vascular disease and blood donation lowers significantly the risk of myocardial infarction (Salonen, 1998), particularly in insulin-resistant subjects. On the contrary, exogenous iron into healthy individuals provoked endothelial dysfunction accompanied by increased generation of superoxide radical in whole blood (Vinchi, 2014, rev). A causal relationship between pre-diabetes and cardiovascular disease exist (Ford, 2010, rev). Humans lack effective mechanisms to excrete excess iron, and excessive dietary iron uptake cause iron deposition in heart, and pancreas (Kulaksis, 2008) leading to sudden death and occult diabetes mellitus. Iron play an underappreciated role in the development of insulin resistance and insulin resistance-induced heart failure. In a chronic and acute way, Insulin resistance is an early and major factor in the development of heart failure and acute iron induced insulin resistance in cardiomyocytes (Sung, 2019). 1- Introduction 2- Catalytic Iron; Irreversible Oxidizer 3- Excess Hemoglobin and Cardiocerebrovascular Pathology 4- Free Iron as a promoter of Ischemic Heart Disease 5- Excess Ferritin and pathogenesis of Endothelial Dysfunction 6- Hyperinsulinemia as a Sudden Death Promoter. The determining role of Iron 7- Iron accumulated in excess and pathogenesis of Diabetes: High hemoglobin versus High Ferritin 8- Iron and atherosclerosis. The evidence 9- Blood Donation. Cardiovascular Pathology Protector

Prenatal hypoxia predisposes vascular functional and structural changes associated with oxidative stress damage and depressive behavior in adult offspring male rats

Article

Mar 2021
PHYSIOL BEHAV

Intrauterine hypoxia-ischemia (HI) provides a strong stimulus for a developmental origin of both the central nervous system and cardiovascular diseases. This study aimed to investigate vascular functional and structural changes, oxidative stress damage, and behavioral alterations in adult male offspring submitted to HI during pregnancy. The pregnant Wistar rats had a uterine artery clamped for 45 min on the 18th gestational day, submitting the offspring to hypoxic-ischemic conditions. The Sham group passed to the same surgical procedure as the HI rats, without occlusion of the maternal uterine artery, and the controls consisted of non-manipulated healthy animals. After weaning, the male pups were divided into three groups: control, sham, and HI, according to the maternal procedure. At postnatal day 90 (P90), the adult male offspring performed the open field and forced swim tests. In P119, the rats had their blood pressure checked and were euthanized. Prenatal HI induced a depressive behavior in adult male offspring associated with a reduced vasodilator response to acetylcholine in perfused mesenteric arterial bed, and reduced superoxide dismutase and glutathione peroxidase activities in the aorta compared to control and sham groups. Prenatal HI also increased the vasoconstrictor response to norepinephrine, the media thickness, collagen deposition, and the oxidative damage in the aorta from adult male offspring compared to control and sham groups. Our results suggest an association among prenatal HI and adult vascular structural and functional changes, oxidative stress damage, and depressive behavior.

CHANGE OF THE OXIDANT AND ANTIOXIDANT STATUS IN THE OFFSPRING FROM RATS WITH EXPERIMENTAL PREECLAMPSIA UNDER THE EFFECT OF GABA DERIVATIVES

Article

Full-text available

Mar 2020

The effect of course intragastric administration of gamma-aminobutyric acid derivatives (GABA) such as succicard 22 mg/kg, salifen 7,5 mg/kg, phenibut 25 mg/kg and comparison of drug pantogam 50 mg on the concentration of malondialdehyde (MDA) and the activity of catalase and superoxide dismutase (SOD) in the plasma of offspring at the age of 8, 14 and 20 months, who was born from rats with experimental preeclampsia (EP), was studied. EP has decreased the activity of antioxidant enzymes and increased concentration of lipid peroxidation products in offspring from females with EP in long periods of ontogenesis (8, 14 and 20 months). The GABA derivatives administration from 40 to 70 days of life to the progeny from rats with EP has decreased MDA level in animals at the age of 8 months treated with salifen, in 14 months - in those receiving succicard and comparison of drug pantogam, in 20 months - pantogam. In addition, the activity of SOD has increased at the age of 14 months in rats, which were treated by succicard, salifen, phenibut, and pantogam, and at 8 and 20 months in those receiving pantogam. An increase in catalase activity was observed at the age of 8 months in the offspring who were treated with phenibut and salifen, at 14 months - who received succicard.

Circular RNA in Aging and Age-Related Diseases: Mechanisms and Interventions

Chapter

Full-text available

Sep 2018
ADV EXP MED BIOL

Circular RNAs (circRNAs) are widely present and participate in a variety of biological regulatory activities as a novel type of endogenous noncoding RNA molecule. With advances in RNA structure and function analysis, it was found that circRNAs are present in a myriad of life processes and longevity in model organisms such as mice, flies, and worms. Accumulating evidence indicates the involvement of circRNAs in regulation of age-related pathologies such as cancer, diabetes, cardiovascular disorders, and neurodegenerative disease, suggesting that circRNAs may have great potential implications in clinical and research fields. In this chapter, we review recent advances in circRNA functions and mechanisms and discuss their roles in aging and age-related diseases. It will provide insight into the regulatory roles of circRNAs in aging and age-related diseases.

The potential mechanism of mitochondrial dysfunction in septic cardiomyopathy

Article

Full-text available

Jun 2018
J INT MED RES

Septic cardiomyopathy is one of the most serious complications of sepsis or septic shock. Basic and clinical research has studied the mechanism of cardiac dysfunction for more than five decades. It has become clear that myocardial depression is not related to hypoperfusion. As the heart is highly dependent on abundant adenosine triphosphate (ATP) levels to maintain its contraction and diastolic function, impaired mitochondrial function is lethally detrimental to the heart. Research has shown that mitochondria play an important role in organ damage during sepsis. The mitochondria-related mechanisms in septic cardiomyopathy have been discussed in terms of restoring mitochondrial function. Mitochondrial uncoupling proteins located in the mitochondrial inner membrane can promote proton leakage across the mitochondrial inner membrane. Recent studies have demonstrated that proton leakage is the essential regulator of mitochondrial membrane potential and the generation of reactive oxygen species (ROS) and ATP. Other mechanisms involved in septic cardiomyopathy include mitochondrial ROS production and oxidative stress, mitochondria Ca²⁺ handling, mitochondrial DNA in sepsis, mitochondrial fission and fusion, mitochondrial biogenesis, mitochondrial gene regulation and mitochondria autophagy. This review will provide an overview of recent insights into the factors contributing to septic cardiomyopathy.

Downregulation of L‐Type Voltage‐Gated Ca 2+ , Voltage‐Gated K + , and Large‐Conductance Ca 2+ ‐Activated K + Channels in Vascular Myocytes From Salt‐Loading Offspring Rats Exposed to Prenatal Hypoxia

Article

Full-text available

Mar 2018

Background: Prenatal hypoxia is suggested to be associated with increased risks of hypertension in offspring. This study tested whether prenatal hypoxia resulted in salt-sensitive offspring and its related mechanisms of vascular ion channel remodeling. Methods and results: Pregnant rats were housed in a normoxic (21% O2) or hypoxic (10.5% O2) chamber from gestation days 5 to 21. A subset of male offspring received a high-salt diet (8% NaCl) from 4 to 12 weeks after birth. Blood pressure was significantly increased only in the salt-loading offspring exposed to prenatal hypoxia, not in the offspring that received regular diets and in control offspring provided with high-salt diets. In mesenteric artery myocytes from the salt-loading offspring with prenatal hypoxia, depolarized resting membrane potential was associated with decreased density of L-type voltage-gated Ca2+(Cav1.2) and voltage-gated K+channel currents and decreased calcium sensitive to the large-conductance Ca2+-activated K+channels. Protein expression of the L-type voltage-gated Ca2+α1C subunit, large-conductance calcium-activated K+channel (β1, not α subunits), and voltage-gated K+channel (KV2.1, not KV1.5 subunits) was also decreased in the arteries of salt-loading offspring with prenatal hypoxia. Conclusions: The results demonstrated that chronic prenatal hypoxia may program salt-sensitive hypertension in male offspring, providing new information of ion channel remodeling in hypertensive myocytes. This information paves the way for early prevention and treatments of salt-induced hypertension related to developmental problems in fetal origins.

Chronic Prenatal Hypoxia Down-Regulated BK Channel Β1 Subunits in Mesenteric Artery Smooth Muscle Cells of the Offspring

Article

Full-text available

Feb 2018

Background/aims: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK) channels in offspring mesenteric arteries following prenatal hypoxia. Methods: Pregnant rats were exposed to normoxic control (21% O2, Con) or hypoxic (10.5% O2, Hy) conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR. Results: Prenatal hypoxia increased pressor responses and vasoconstrictions to phenylephrine in the offspring. Whole-cell currents density of BK channels and amplitude of spontaneous transient outward currents (STOCs), not the frequency, were significantly reduced in Hy vascular myocytes. The sensitivity of BK channels to voltage, Ca2+, and tamoxifen were reduced in Hy myocytes, whereas the number of channels per patch and the single-channel conductance were unchanged. Prenatal hypoxia impaired NS1102- and tamoxifen-mediated relaxation in mesenteric arteries precontracted with phenylephrine in the presence of Nω-nitro-L-arginine methyl ester. The mRNA and protein expression of BK channel β1, not the α-subunit, was decreased in Hy mesenteric arteries. Conclusions: Impaired BK channel β1-subunits in vascular smooth muscle cells contributed to vascular dysfunction in the offspring exposed to prenatal hypoxia.

Prenatal Hypoxia Induced Dysfunction in Cerebral Arteries of Offspring Rats

Article

Full-text available

Oct 2017

Background Hypoxia during pregnancy could cause abnormal development and lead to increased risks of vascular diseases in adults. This study determined angiotensin II (AII)‐mediated vascular dysfunction in offspring middle cerebral arteries (MCA). Methods and Results Pregnant rats were subjected to hypoxia. Vascular tension in offspring MCA by AII with or without inhibitors, calcium channel activities, and endoplasmic reticulum calcium stores were tested. Whole‐cell patch clamping was used to investigate voltage‐dependent calcium channel currents. mRNA expression was tested using quantitative real‐time polymerase chain reaction. AII‐mediated MCA constriction was greater in male offspring exposed to prenatal hypoxia. AT1 and AT2 receptors were involved in the altered AII‐mediated vasoconstriction. Prenatal hypoxia increased baseline activities of L‐type calcium channel currents in MCA smooth muscle cells. However, calcium currents stimulated by AII were not significantly changed, whereas nifedipine inhibited AII‐mediated vasoconstrictions in the MCA. Activities of IP3/ryanodine receptor–operated calcium channels, endoplasmic reticulum calcium stores, and sarcoendoplasmic reticulum membrane Ca²⁺‐ATPase were increased. Prenatal hypoxia also caused dysfunction of vasodilatation via the endothelium NO synthase. The mRNA expressions of AT1A, AT1B, AT2R, Cav1.2α1C, Cav3.2α1H, and ryanodine receptor RyR2 were increased in the prenatal‐hypoxia group. Conclusions Hypoxia in pregnancy could induce dysfunction in both contraction and dilation in the offspring MCA. AII‐increased constriction in the prenatal‐hypoxia group was not mainly dependent on the L‐type and T‐type calcium channels; it might predominantly rely on the AII receptors, IP3/ryanodine receptors, and the endoplasmic reticulum calcium store as well as calcium ATPase.

Paracetamol: overdose-induced oxidative stress toxicity, metabolism, and protective effects of various compounds in vivo and in vitro

Article

Full-text available

Aug 2017

Paracetamol (APAP) is one of the most widely used and popular over-the-counter analgesic and antipyretic drugs in the world when used at therapeutic doses. APAP overdose can cause severe liver injury, liver necrosis and kidney damage in human beings and animals. Many studies indicate that oxidative stress is involved in the various toxicities associated with APAP, and various antioxidants were evaluated to investigate their protective roles against APAP-induced liver and kidney toxicities. To date, almost no review has addressed the APAP toxicity in relation to oxidative stress. This review updates the research conducted over the past decades into the production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and oxidative stress as a result of APAP treatments, and ultimately their correlation with the toxicity and metabolism of APAP. The metabolism of APAP involves various CYP450 enzymes, through which oxidative stress might occur, and such metabolic factors are reviewed within. The therapeutics of a variety of compounds against APAP-induced organ damage based on their anti-oxidative effects is also discussed, in order to further understand the role of oxidative stress in APAP-induced toxicity. This review will throw new light on the critical roles of oxidative stress in APAP-induced toxicity, as well as on the contradictions and blindspots that still exist in the understanding of APAP toxicity, the cellular effects in terms of organ injury and cell signaling pathways, and finally strategies to help remedy such against oxidative damage.

Endothelial dysfunction in individuals born after fetal growth restriction: cardiovascular and renal consequences and preventive approaches

Article

Full-text available

May 2017

Individuals born after intrauterine growth restriction (IUGR) have an increased risk of perinatal morbidity/mortality, and those who survive face long-term consequences such as cardiovascular-related diseases, including systemic hypertension, atherosclerosis, coronary heart disease and chronic kidney disease. In addition to the demonstrated long-term effects of decreased nephron endowment and hyperactivity of the hypothalamic–pituitary–adrenal axis, individuals born after IUGR also exhibit early alterations in vascular structure and function, which have been identified as key factors of the development of cardiovascular-related diseases. The endothelium plays a major role in maintaining vascular function and homeostasis. Therefore, it is not surprising that impaired endothelial function can lead to the long-term development of vascular-related diseases. Endothelial dysfunction, particularly impaired endothelium-dependent vasodilation and vascular remodeling, involves decreased nitric oxide (NO) bioavailability, impaired endothelial NO synthase functionality, increased oxidative stress, endothelial progenitor cells dysfunction and accelerated vascular senescence. Preventive approaches such as breastfeeding, supplementation with folate, vitamins, antioxidants, L-citrulline, L-arginine and treatment with NO modulators represent promising strategies for improving endothelial function, mitigating long-term outcomes and possibly preventing IUGR of vascular origin. Moreover, the identification of early biomarkers of endothelial dysfunction, especially epigenetic biomarkers, could allow early screening and follow-up of individuals at risk of developing cardiovascular and renal diseases, thus contributing to the development of preventive and therapeutic strategies to avert the long-term effects of endothelial dysfunction in infants born after IUGR.

Maternal high-salt diet altered PKC/MLC20 pathway and increased ANG II receptor-mediated vasoconstriction in adult male rat offspring

Article

Full-text available

Mar 2016
MOL NUTR FOOD RES

Scope: High-salt diet (HSD) is associated with cardiovascular diseases. This study aims at ascertaining the influence of maternal HSD on offspring's angiotensin II (ANG II)-mediated vasoconstriction and the underlying mechanisms. Methods and results: In comparison to a normal-salt diet (NSD), HSD used in pregnancy in rats changed the ultrastructures of the coronary artery (CA) in 5-month-old male offspring, and increased ANG II-mediated CA contractility. Measurement of [Ca(2+) ]i in CA using fluorescent fura-2, a Ca(2+) indicator, showed that ANG II-mediated increases in [Ca(2+) ]i were the same between HSD and NSD groups,but the ratio of diameter change/[Ca(2+) ]i -induced by ANG II were significantly higher in HSD groups. angiotensin II receptor type 1 (AT1 R), not AT2 R, caused ANG II-mediated vasoconstriction. Protein kinase C (PKC) inhibitor GF109203X attenuated the ANG II-mediated vasoconstriction, PKC agonist phorbol12,13-dibutyrate produced a greater contraction. There was an increase in PKCβ mRNA and the corresponding protein abundance in the offspring, whereas other PKC subunits PKCα, PKCδ, and PKCε did not change. Moreover, 20-kDa myosin light chain phosphorylation levels were increased in HSD group. Conclusion: Maternal HSD affected the developmental programming for the offspring CA, with increased ANG II-mediated vasoconstrictions. The AT1 R-PKC-MLC20-P pathway was the possible mediated cellular mechanism. This article is protected by copyright. All rights reserved.

Muscarinic acetylcholine receptor M1 and M3 subtypes mediate acetylcholine-induced endothelium-independent vasodilatation in rat mesenteric arteries

Article

Full-text available

Jan 2016

The present study investigated pharmacological characterizations of muscarinic acetylcholine receptor (AChR) subtypes involving ACh-induced endothelium-independent vasodilatation in rat mesenteric arteries. Changes in perfusion pressure to periarterial nerve stimulation and ACh were measured before and after the perfusion of Krebs solution containing muscarinic receptor antagonists. Distributions of muscarinic AChR subtypes in mesenteric arteries with an intact endothelium were studied using Western blotting. The expression level of M1 and M3 was significantly greater than that of M2. Endothelium removal significantly decreased expression levels of M2 and M3, but not M1. In perfused mesenteric vascular beds with intact endothelium and active tone, exogenous ACh (1, 10, and 100 nmol) produced concentration-dependent and long-lasting vasodilatations. In endothelium-denuded preparations, relaxation to ACh (1 nmol) disappeared, but ACh at 10 and 100 nmol caused long-lasting vasodilatations, which were markedly blocked by the treatment of pirenzepine (M1 antagonist) or 4-DAMP (M1 and M3 antagonist) plus hexamethonium (nicotinic AChR antagonist), but not methoctramine (M2 and M4 antagonist). These results suggest that muscarinic AChR subtypes, mainly M1, distribute throughout the rat mesenteric arteries, and that activation of M1 and/or M3 which may be located on CGRPergic nerves releases CGRP, causing an endothelium-independent vasodilatation.

Decreased reactive oxygen species production and NOX1, NOX2, NOX4 expression contribute to hyporeactivity to phenylephrine in aortas of pregnant SHR

Article

Full-text available

Dec 2015

Aims: We determined whether decreased reactive oxygen species (ROS) production in the aorta of pregnant spontaneously hypertensive rats (SHR) resulted in increased nitric oxide (NO) bioavailability and hyporeactivity to phenylephrine (PE). Main methods: Systemic and aortic oxidative stress were measured in pregnant and non-pregnant Wistar rats and SHR. Furthermore, the hypotensive effects of apocynin (30mg/kg) and tempol (30mg/kg) were analyzed. Intact aortic rings of pregnant and non-pregnant rats were stimulated with PE in absence or after incubation (30min) with apocynin (100μmol/L). The effect of apocynin on the concentrations of NO and ROS were measured in aortic endothelial cells (AEC) using DAF-2DA (10mmol/L) and DHE (2.5mmol/L), respectively. Western blotting was performed to analyze eNOS, NOX1, NOX2, NOX4 and SOD expression. ROS production was analyzed by lucigenin chemiluminescence method. Key findings: Aortic oxidative stress and ROS concentration in AEC were reduced in pregnant Wistar and SHR, when compared to non-pregnant rats. ROS production and NOX1, NOX2 and NOX4 expression in the aortas were decreased in pregnant SHR, but not in pregnant Wistar rats. Increased eNOS expression in aortas and NO concentration in AEC were observed in pregnant Wistar and SHR. Apocynin reduced PE-induced vasoconstrictions in aorta of non-pregnant Wistar and SHR, pregnant Wistar rats, but not in the aortas of pregnant SHR. Significance: Taken together, these results suggest that ROS production was decreased in the aortas of pregnant SHR and could contribute to higher NO bioavailability and hyporeactivity to PE in the aortas of pregnant SHR.

Chronic hypoxia in pregnancy affected vascular tone of renal interlobar arteries in the offspring

Article

Full-text available

May 2015

Hypoxia during pregnancy could affect development of fetuses as well as cardiovascular systems in the offspring. This study was the first to demonstrate the influence and related mechanisms of prenatal hypoxia (PH) on renal interlobar arteries (RIA) in the 5-month-old male rat offspring. Following chronic hypoxia during pregnancy, phenylephrine induced significantly higher pressor responses and greater vasoconstrictions in the offspring. Nitric oxide mediated vessel relaxation was altered in the RIA. Phenylephrine-stimulated free intracellular calcium was significantly higher in the RIA of the PH group. The activity and expression of L-type calcium channel (Cav1.2), not T-type calcium channel (Cav3.2), was up-regulated. The whole-cell currents of calcium channels and the currents of Cav1.2 were increased compared with the control. In addition, the whole-cell K + currents were decreased in the offspring exposed to prenatal hypoxia. Activity of large-conductance Ca 2+-activated K + channels and the expression of MaxiKα was decreased in the PH group. The results provide new information regarding the influence of prenatal hypoxia on the development of the renal vascular system, and possible underlying cellular and ion channel mechanisms involved.

Polygonum viviparum L. induces vasorelaxation in the rat thoracic aorta via activation of nitric oxide synthase in endothelial cells

Article

Full-text available

May 2014
BMC Compl Alternative Med

Background In the past several decades, Polygonum viviparum L. (PV) was reported to have antibacterial, antiulcer, antioxidant, antitumor, anti-inflammatory, and antiarthritic properties. The anti-inflammatory pathway was recently elucidated through cytosolic nuclear factor E2-related factor 2 (Nrf2) activation and heme oxygenase (HO)-1 protein expression. PV is a perennial herb and widely distributed in high-elevation mountain regions, such as the Tibetan Plateau. In Tibetan traditional medicine, PV is usually used to boost the blood circulation to dissipate blood stasis. Therefore, this study focused on how PV improves the vascular circulation and acts on vascular tissues. Methods In this study, we isolated aortas from Sprague-Dawley rats (male, weight about 250 ~ 350 g), and detected the effects of PV on phenylephrine (PE)-induced contraction and cyclic guanosine 3′,5′-monophosphate (cGMP) formation using aortic rings. In addition, human umbilical vein endothelial cells (HUVECs) were used to exam nitric oxygen (NO) synthase (NOS) activity by directly measuring NO production in the culture medium. Endothelial (e) NOS phosphorylation, and cytosolic Nrf2 and HO-1 expressions were measured using a Western blot analysis. Results PV dose-dependently relaxed PE-induced contractions in endothelial-intact but not -denuded aorta. The concentration to produce 50% relaxation was 22.04 ± 1.77 μg/ml. PV-induced vasorelaxation was markedly blocked by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), an NOS inhibitor, methylene blue (MB), a guanylyl cyclase inhibitor, and hemoglobin, an NO scavenger. PV increased cGMP formation; however, this effect was also suppressed by co-pretreatment with l-NAME, MB, hemoglobin, and Ca2+-free medium. In HUVECs, PV increased NO formation, which was greatly attenuated by NOS inhibitors (L-NAME and L-NMMA) and by removing extracellular Ca2+ and chelating intracellular Ca2+ with BAPTA-AM. In addition, PV promoted eNOS phosphorylation, Nrf2 degradation, and HO-1 protein expression according to a Western blot analysis. Conclusions The results suggest that PV possesses vasorelaxing action in an endothelium-dependent manner and works through activating Ca2+/calmodulin- dependent NO synthesis; when NO is released and then transferred to smooth muscle cells, NO activates guanylyl cyclase and increases cGMP formation, ultimately resulting in vasorelaxation. Thus, PV can be considered for application as a potential therapeutic approach for vascular-associated disorders.

End-Systolic Elastance and Ventricular-Arterial Coupling Reserve Predict Cardiac Events in Patients with Negative Stress Echocardiography

Article

Full-text available

Jan 2013
BMRI

Background: A maximal negative stress echo identifies a low-risk subset for coronary events. However, the potentially prognostically relevant information on cardiovascular hemodynamics for heart-failure-related events is unsettled. Aim of this study was to assess the prognostic value of stress-induced variation in cardiovascular hemodynamics in patients with negative stress echocardiography. Methods: We enrolled 891 patients (593 males mean age 63 ± 12, ejection fraction 48 ± 17%), with negative (exercise 172, dipyridamole 482, and dobutamine 237) stress echocardiography result. During stress we assessed left ventricular end-systolic elastance index (E(LV)I), ventricular arterial coupling (VAC) indexed by the ratio of the E(LV)I to arterial elastance index (E aI), systemic vascular resistance (SVR), and pressure-volume area (PVA). Changes from rest to peak stress (reserve) were tested as predictors of main outcome measures: combined death and heart failure hospitalization. Results: During a median followup of 19 months (interquartile range 8-36), 50 deaths and 84 hospitalization occurred. Receiver-operating-characteristic curves identified as best predictors E(LV)I reserve for exercise (AUC = 0.871) and dobutamine (AUC = 0.848) and VAC reserve (AUC = 0.696) for dipyridamole. Conclusions: Patients with negative stress echocardiography may experience an adverse outcome, which can be identified by assessment of E(LV)I reserve and VAC reserve during stress echo.

Acetylcholine Attenuates Hypoxia/Reoxygenation-Induced Mitochondrial and Cytosolic ROS Formation in H9c2 Cells via M2 Acetylcholine Receptor

Article

Full-text available

Feb 2013
CELL PHYSIOL BIOCHEM

Background: The anti-infammatory and cardioprotective effect of acetylcholine (ACh) has been reported; nevertheless, whether and how ACh exhibits an antioxidant property against ischemia/reperfusion (I/R)-induced oxidative stress remains obscure. Methods: In the present study, H9c2 rat cardiomyocytes were exposed to hypoxia/reoxygenation (H/R) to mimic I/R injury. We estimated intracellular different sources of reactive oxygen species (ROS) by measuring mitochondrial ROS (mtROS), mitochondrial DNA (mtDNA) copy number, xanthine oxidase (XO) and NADPH oxidase (NOX) activity and expression of rac 1. Cell injury was determined by lactate dehydrogenase (LDH) release and cleaved caspase-3 expression. The siRNA transfection was performed to knockdown of M2 acetylcholine receptor (M2 AChR) expression. Results: 12-h hypoxia followed by 2-h reoxygenation resulted in an abrupt burst of ROS in H9c2 cells. Administration of ACh reduced the levels of ROS in a concentration-dependent manner. Compared to the H/R group, ACh decreased mtROS, recovered mtDNA copy number, diminished XO and NOX activity, rac 1 expression as well as cell injury. Co- treatment with atropine rather than hexamethonium abolished the antioxidant and cardioprotective effect of ACh. Moreover, knockdown of M2 AChR by siRNA showed the similar trends as atropine co-treatment group. Conclusions: ACh inhibits mitochondria-, XO- and NOX-derived ROS production thus protecting H9c2 cells against H/R-induced oxidative stress, and these benefcial effects are mainly mediated by M2 AChR. Our findings suggested that increasing ACh release could be a potential therapeutic strategy for treatment and prevention of I/R injury.

Synergistic effects of prenatal hypoxia and postnatal high-fat diet in the development of cardiovascular pathology in young rats

Article

Full-text available

Jun 2012
AM J PHYSIOL-REG I

We have previously shown that adult offspring exposed to a prenatal hypoxic insult leading to intrauterine growth restriction (IUGR) are more susceptible to cardiovascular pathologies. Our objectives were to evaluate the interaction between hypoxia-induced IUGR and postnatal diet in the early development of cardiovascular pathologies. Furthermore, we sought to determine whether the postnatal administration of resveratrol could prevent the development of cardiovascular disorders associated with hypoxia-induced IUGR. On day 15 of pregnancy, Sprague-Dawley rats were randomly assigned to hypoxia (11.5% oxygen), to induce IUGR, or normal oxygen (control) groups. For study A, male offspring (3 wk of age) were randomly assigned a low-fat (LF, <10% fat) or a high-fat (HF, 45% fat) diet. For study B, offspring were randomized to either HF or HF+resveratrol diets. After 9 wk, cardiac and vascular functions were evaluated. Prenatal hypoxia and HF diet were associated with an increased myocardial susceptibility to ischemia. Blood pressure, in vivo cardiac function, and ex vivo vascular function were not different among experimental groups; however, hypoxia-induced IUGR offspring had lower resting heart rates. Our results suggest that prenatal insults can enhance the susceptibility to a second hit such as myocardial ischemia, and that this phenomenon is exacerbated, in the early stages of life by nutritional stressors such as a HF diet. Supplementing HF diets with resveratrol improved cardiac tolerance to ischemia in offspring born IUGR but not in controls. Thus we conclude that the additive effect of prenatal (hypoxia-induced IUGR) and postnatal (HF diet) factors can lead to the earlier development of cardiovascular pathology in rats, and postnatal resveratrol supplementation prevented the deleterious cardiovascular effects of HF diet in offspring exposed to prenatal hypoxia.

Chronic nicotine induces hypoxia inducible factor-2α in perinatal rat adrenal chromaffin cells: Role in transcriptional upregulation of KATP channel subunit Kir6.2

Article

Full-text available

Mar 2012
AM J PHYSIOL-CELL PH

Fetal nicotine exposure causes impaired adrenal catecholamine secretion and increased neonatal mortality during acute hypoxic challenges. Both effects are attributable to upregulation of ATP-sensitive K(+) channels (K(ATP) channels) and can be rescued by pretreatment with the blocker, glibenclamide. Although use of in vitro models of primary and immortalized, fetal-derived rat adrenomedullary chromaffin cells (i.e., MAH cells) demonstrated the involvement of α7 nicotinic ACh receptor (nAChR) stimulation and the transcription factor, HIF-2α, the latter's role was unclear. Using Western blots, we show that chronic nicotine causes a progressive, time-dependent induction of HIF-2α in MAH cells that parallels the upregulation of K(ATP) channel subunit, Kir6.2. Moreover, a common HIF target, VEGF mRNA, was also upregulated after chronic nicotine. All the above effects were prevented during co-incubation with α-bungarotoxin (100 nM), a specific α7 nAChR blocker, and were absent in HIF-2α-deficient MAH cells. Chromatin immunoprecipitation (ChIP) assays demonstrated binding of HIF-2α to a putative hypoxia response element in Kir6.2 gene promoter. Specificity of this signaling pathway was validated in adrenal glands from pups born to dams exposed to nicotine throughout gestation; the upregulation of both HIF-2α and Kir6.2 was confined to medullary, but not cortical, tissue. This study has uncovered a signaling pathway whereby a nonhypoxic stimulus (nicotine) promotes HIF-2α-mediated transcriptional upregulation of a novel target, Kir6.2 subunit. The data suggest that the HIF pathway may be involved in K(ATP) channel-mediated neuroprotection during brain ischemia, and in the effects of chronic nicotine on ubiquitous brain α7 nAChR.

Developmental Programming of Cardiovascular Dysfunction by Prenatal Hypoxia and Oxidative Stress

Article

Full-text available

Feb 2012
PLOS ONE

Fetal hypoxia is a common complication of pregnancy. It has been shown to programme cardiac and endothelial dysfunction in the offspring in adult life. However, the mechanisms via which this occurs remain elusive, precluding the identification of potential therapy. Using an integrative approach at the isolated organ, cellular and molecular levels, we tested the hypothesis that oxidative stress in the fetal heart and vasculature underlies the molecular basis via which prenatal hypoxia programmes cardiovascular dysfunction in later life. In a longitudinal study, the effects of maternal treatment of hypoxic (13% O(2)) pregnancy with an antioxidant on the cardiovascular system of the offspring at the end of gestation and at adulthood were studied. On day 6 of pregnancy, rats (n = 20 per group) were exposed to normoxia or hypoxia ± vitamin C. At gestational day 20, tissues were collected from 1 male fetus per litter per group (n = 10). The remaining 10 litters per group were allowed to deliver. At 4 months, tissues from 1 male adult offspring per litter per group were either perfusion fixed, frozen, or dissected for isolated organ preparations. In the fetus, hypoxic pregnancy promoted aortic thickening with enhanced nitrotyrosine staining and an increase in cardiac HSP70 expression. By adulthood, offspring of hypoxic pregnancy had markedly impaired NO-dependent relaxation in femoral resistance arteries, and increased myocardial contractility with sympathetic dominance. Maternal vitamin C prevented these effects in fetal and adult offspring of hypoxic pregnancy. The data offer insight to mechanism and thereby possible targets for intervention against developmental origins of cardiac and peripheral vascular dysfunction in offspring of risky pregnancy.

Aging impairs vasodilatory responses in rats

Article

Full-text available

Dec 2011
Korean J Anesthesiol

Aging causes profound changes of stiffness and compliance in the cardiovascular system, which contributes to decreased cardiovascular reserve. Mechanisms of the underlying endothelial vasodilator dysfunction in vasodilator signaling pathways may occur at multiple sites within any of these pathways. Age-related changes in the vasculature were investigated in adult young (3-6 months, Y) and old (26-29 month, O) Wistar rats (n = 6). The aortas were carefully dissected from the rat and cut into rings 1.5-2.0 mm in length to measure in vitro isometric tension. Vasorelaxant responses of aortic rings to acetylcholine (ACh), sodium nitroprusside (SNP) and P1075 were examined using Dose Response software (AD Instruments, Mountain View, CA). Endothelium-dependent vasodilator function was impaired. The endothelium of aging rats impaired endothelial NO dependent vasodilation, but the machinery for vasodilation was not impaired. Age-related NO-mediated vasorelaxation in the aging endothelium was inhibited and appears to be major mechanism of vascular change and impaired vascular regulation.

Upregulation of Nox1 in Vascular Smooth Muscle Leads to Impaired Endothelium-Dependent Relaxation via eNOS Uncoupling

Article

Full-text available

Sep 2010
AM J PHYSIOL-HEART C

Recent work has made it clear that oxidant systems interact. To investigate potential cross talk between NADPH oxidase (Nox) 1 upregulation in vascular smooth muscle and endothelial function, transgenic mice overexpressing Nox1 in smooth muscle cells (Tg(SMCnox1)) were subjected to angiotensin II (ANG II)-induced hypertension. As expected, NADPH-dependent superoxide generation was increased in aortas from Nox1-overexpressing mice. Infusion of ANG II (0.7 mg x kg(-1) x day(-1)) for 2 wk potentiated NADPH-dependent superoxide generation and hydrogen peroxide production compared with similarly treated negative littermate controls. Endothelium-dependent relaxation was impaired in transgenic mice, and bioavailable nitric oxide was markedly decreased. To test the hypothesis that eNOS uncoupling might contribute to endothelial dysfunction, the diet was supplemented with tetrahydrobiopterin (BH(4)). BH(4) decreased aortic superoxide production, partially restored bioavailable nitric oxide in aortas of ANG II-treated Tg(SMCnox1) mice, and significantly improved endothelium-dependent relaxation in these mice. Western blot analysis revealed less dimeric eNOS in Tg(SMCnox1) mice compared with the wild-type mice; however, total eNOS was equivalent. Pretreatment of mouse aortas with the eNOS inhibitor N(G)-nitro-L-arginine methyl ester decreased ANG II-induced superoxide production in Tg(SMCnox1) mice compared with wild-type mice, indicating that uncoupled eNOS is also a significant source of increased superoxide in transgenic mice. Thus overexpression of Nox1 in vascular smooth muscle leading to enhanced production of reactive oxygen species in response to ANG II causes eNOS uncoupling and a decrease in nitric oxide bioavailability, resulting in impaired vasorelaxation.

Arginase inhibition restores NOS coupling and reverses endothelial dysfunction and vascular stiffness in old rats

Article

Full-text available

Sep 2009
J APPL PHYSIOL

There is increasing evidence that upregulation of arginase contributes to impaired endothelial function in aging. In this study, we demonstrate that arginase upregulation leads to endothelial nitric oxide synthase (eNOS) uncoupling and that in vivo chronic inhibition of arginase restores nitroso-redox balance, improves endothelial function, and increases vascular compliance in old rats. Arginase activity in old rats was significantly increased compared with that shown in young rats. Old rats had significantly lower nitric oxide (NO) and higher superoxide (O2(-)) production than young. Acute inhibition of both NOS, with N(G)-nitro-l-arginine methyl ester, and arginase, with 2S-amino- 6-boronohexanoic acid (ABH), significantly reduced O2(-) production in old rats but not in young. In addition, the ratio of eNOS dimer to monomer in old rats was significantly decreased compared with that shown in young rats. These results suggest that eNOS was uncoupled in old rats. Although the expression of arginase 1 and eNOS was similar in young and old rats, inducible NOS (iNOS) was significantly upregulated. Furthermore, S-nitrosylation of arginase 1 was significantly elevated in old rats. These findings support our previously published finding that iNOS nitrosylates and activates arginase 1 (Santhanam et al., Circ Res 101: 692-702, 2007). Chronic arginase inhibition in old rats preserved eNOS dimer-to-monomer ratio and significantly reduced O2(-) production and enhanced endothelial-dependent vasorelaxation to ACh. In addition, ABH significantly reduced vascular stiffness in old rats. These data indicate that iNOS-dependent S-nitrosylation of arginase 1 and the increase in arginase activity lead to eNOS uncoupling, contributing to the nitroso-redox imbalance, endothelial dysfunction, and vascular stiffness observed in vascular aging. We suggest that arginase is a viable target for therapy in age-dependent vascular stiffness.

The Four-and-a-half LIM Domain Protein 2 Regulates Vascular Smooth Muscle Phenotype and Vascular Tone

Article

Full-text available

Apr 2009

In response to vascular injury, differentiated vascular smooth muscle cells (vSMCs) undergo a unique process known as “phenotype modulation,” transitioning from a quiescent, “contractile” phenotype to a proliferative, “synthetic” state. We have demonstrated previously that the signaling pathway of bone morphogenetic proteins, members of the transforming growth factor β family, play a role in the induction and maintenance of a contractile phenotype in human primary pulmonary artery smooth muscle cells. In this study, we show that a four-and-a-half LIM domain protein 2 (FHL2) inhibits transcriptional activation of vSMC-specific genes mediated by the bone morphogenetic protein signaling pathway through the CArG box-binding proteins, such as serum response factor and members of the myocardin (Myocd) family. Interestingly, FHL2 does not affect recruitment of serum response factor or Myocd, however, it inhibits recruitment of a component of the SWI/SNF chromatin remodeling complex, Brg1, and RNA polymerase II, which are essential for the transcriptional activation. This is a novel mechanism of regulation of SMC-specific contractile genes by FHL2. Finally, aortic rings from homozygous FHL2-null mice display abnormalities in both endothelial-dependent and -independent relaxation, suggesting that FHL2 is essential for the regulation of vasomotor tone.

Long-term effects of prenatal hypoxia on endothelium-dependent relaxation responses in pulmonary arteries of adult sheep

Article

Full-text available

Feb 2009

Chronic hypoxia during the course of pregnancy is a common insult to the fetus. However, its long-term effect on the pulmonary vasculature in adulthood has not been described. In this study, the vasorelaxation responses of conduit pulmonary arteries in adult female sheep that were chronically hypoxic as fetuses and raised postnatally at sea level were investigated. Vessel tension studies revealed that endothelium-dependent relaxation responses were attenuated in pulmonary arteries from adult sheep that experienced prenatal hypoxia. Endothelial nitric oxide synthase (eNOS) protein expression was unchanged, but eNOS activity was significantly decreased in pulmonary arteries from prenatally hypoxic sheep. Protein expression of eNOS partners, caveolin-1, calmodulin, and heat shock protein 90 (Hsp90) did not change following prenatal hypoxia. However, the association between eNOS and caveolin-1, its inhibitory binding partner, was significantly increased, whereas association between eNOS and its stimulatory partners calmodulin and Hsp90 was greatly decreased. Furthermore, phosphorylation of Ser(1177) in eNOS decreased, whereas phosphorylation of Thr(495) increased, in the prenatally hypoxic pulmonary arteries, events that are related to eNOS activity. These data demonstrate that prenatal hypoxia results in persistent abnormalities in endothelium-dependent relaxation responses of pulmonary arteries in adult sheep due to decreased eNOS activity resulting from altered posttranslational regulation.

Elevated blood pressures in mice lacking endothelial nitric oxide synthase

Article

Full-text available

Dec 1996

Nitric oxide produced in endothelial cells affects vascular tone. To investigate the role of endothelial nitric oxide synthase (eNOS) in blood pressure regulation, we have generated mice heterozygous (+/-) or homozygous (-/-) for disruption of the eNOS gene. Immunohistochemical staining with anti-eNOS antibodies showed reduced amounts of eNOS protein in +/- mice and absence of eNOS protein in -/- mutant mice. Male or female mice of all three eNOS genotypes were indistinguishable in general appearance and histology, except that -/- mice had lower body weights than +/+ or +/- mice. Blood pressures tended to be increased (by approximately 4 mmHg) in +/- mice compared with +/+, while -/- mice had a significant increase in pressure compared with +/+ mice (approximately 18 mmHg) or +/- mice (approximately 14 mmHg). Plasma renin concentration in the -/- mice was nearly twice that of +/+ mice, although kidney renin mRNA was modestly decreased in the -/- mice. Heart rates in the -/- mice were significantly lower than in +/- or +/+ mice. Appropriate genetic controls show that these phenotypes in F2 mice are due to the eNOS mutation and are not due to sequences that might differ between the two parental strains (129 and C57BL/6J) and are linked either to the eNOS locus or to an unlinked chromosomal region containing the renin locus. Thus eNOS is essential for maintenance of normal blood pressures and heart rates. Comparisons between the current eNOS mutant mice and previously generated inducible nitric oxide synthase mutants showed that homozygous mutants for the latter differ in having unaltered blood pressures and heart rates; both are susceptible to lipopolysaccharide-induced death.

Article

Jun 2018
EXP GERONTOL

Aging in humans represents declining in cardio-protective systems, however its mechanisms are not known yet. We aimed to analyse how aging affects key mechanisms responsible for contractile dysfunction via comparing the improperly synchrony between electrical and mechanical activities in male aged-rats (24-month old) comparison to those of adult-rats (6-month old). We determined significantly increased systemic oxidative stress with decreased antioxidant capacity, clear insulin resistance and hypertrophy in aged-rats with normal fasting blood glucose. We also determined significantly high level of reactive oxygen species, ROS production in fluorescent dye chloromethyl-2',7'-dichlorodihydrofluoroscein diacetate (DCFDA) loaded isolated cardiomyocytes from aged-rats, confirming the increased oxidative stress in these hearts. In situ electrocardiograms, ECGs presented significant prolongations in RR- and QT-intervals in the aged-rats. Invasive hemodynamic measurements demonstrated marked increases in the heart rate and mean arterial pressure and decreases in the ejection-fraction and preload-recruitable stroke-work, together with depressed contraction and relaxation activities in aortic rings. In light and electron microscopy examinations in aged-rats, significant increases in muscle fibre radius and amount of collagen fibres were detected in the heart as well as markedly flattened and partial local splitting in elastic lamellas in the aorta, besides irregularly clustered mitochondria and lysosomes around the myofilaments in cardiomyocytes. MitoTEMPO treatment of tissue samples and cardiomyocytes from aged-rats for 1-h induced significant structural improvements. In the second part of our study, we have shown that mitochondria-targeted antioxidant MitoTEMPO antagonized all alterations in the heart samples as well as penylephrine-induced contractile and acetylcholine-induced relaxation responses of aged-rat aortic rings. Overall, the present data strongly support the important role of mitochondrial oxidative stress in the development of aged-related insufficiencies and that antioxidant strategies specifically targeting this organelle could have therapeutic benefit in aging-associated complications.

Endothelial C-Type Natriuretic Peptide Acts on Pericytes to Regulate Microcirculatory Flow and Blood Pressure

Article

Apr 2018

Background -Peripheral vascular resistance has a major impact on arterial blood pressure levels. Endothelial C-type natriuretic peptide (CNP) participates in the local regulation of vascular tone but the target cells remain controversial. The cGMP-producing guanylyl cyclase-B (GC-B) receptor for CNP is expressed in vascular smooth muscle cells (VSMC). However, whereas endothelial cell-specific CNP knockout mice are hypertensive, mice with deletion of GC-B in VSMC have unaltered blood pressure. Methods -We analyzed whether the vasodilating response to CNP changes along the vascular tree, i.e. whether the GC-B receptor is expressed in microvascular types of cells. Mice with a floxed GC-B (Npr2) gene were interbred withTie2-CreorPDGF-Rβ-CreERT2lines to develop mice lacking GC-B in endothelial cells or in precapillary arteriolar SMC and capillary pericytes. Intravital microscopy, (non)invasive hemodynamics, fluorescence energy transfer studies of pericyte's cAMP levelsin situand renal physiology were combined to dissect whether and how CNP/GC-B/cGMP signaling modulates microcirculatory tone and blood pressure. Results -Intravital microscopy studies revealed that the vasodilatatory effect of CNP increases towards small-diameter arterioles and capillaries. Consistently, CNP did not prevent endothelin-1-induced acute constrictions of proximal arterioles but fully reversed endothelin effects in precapillary arterioles and capillaries. Here, the GC-B receptor is expressed both in endothelial and mural cells, i.e. in pericytes. Notably, the vasodilatatory effects of CNP were preserved in mice with endothelial GC-B deletion but abolished in mice lacking GC-B in microcirculatory SMC and pericytes. CNP, via GC-B/cGMP signaling modulates two signaling cascades in pericytes: it activates cGMP-dependent protein kinase I to phosphorylate downstream targets such as the cytoskeleton-associated vasodilator activated phosphoprotein; and it inhibits phosphodiesterase 3A, thereby enhancing pericyte's cAMP levels. Ultimately these pathways prevent endothelin-induced increases of pericyte calcium levels and pericyte contraction. Mice with deletion of GC-B in microcirculatory SMC and pericytes have elevated peripheral resistance and chronic arterial hypertension without a change in renal function. Conclusions -Our studies indicate that endothelial CNP regulates distal arteriolar and capillary blood flow. CNP-induced GC-B/cGMP signaling in microvascular SMC and pericytes is essential for the maintenance of normal microvascular resistance and blood pressure.

Intermittent hypoxia in utero damages postnatal growth and cardiovascular function in rats

Article

Dec 2017

Purpose: Obstructive sleep apnea (OSA) is common in pregnancy, and may compromise fetal and even postnatal development. We developed an animal model to determine if maternal OSA could have lasting effects in offspring. Methods: Pregnant Sprague Dawley rats were exposed to reduced ambient O2 from 21 to 4-5 %, approximately once/minute (chronic intermittent hypoxia - CIH) for 8 hours/day during gestation days 3-19. Similarly-handled animals exposed to ambient air served as controls (HC). Offspring were studied for body growth and cardiovascular function for 8 postnatal weeks. Results: Compared with HC, prenatal CIH led to growth restriction, indicated by smaller body weight and tibial length, and higher arterial blood pressure in both male and female offspring. Compared to same-sex HC, CIH males showed abdominal obesity (greater ratio of abdominal fat weight to body weight or tibial length), left ventricular (LV) hypertrophy (greater heart weight to tibial length ratio and LV posterior wall diastolic thickness), elevated LV contractility (increases in LV ejection fraction, end-systolic pressure-volume relations and preload recruitable stroke work), elevated LV and arterial stiffness (increased end-diastolic pressure-volume relationship and arterial elasticity), and LV oxidative stress (greater lipid peroxide content). Compared to female CIH offspring, male CIH offspring had more profound changes in blood pressure (BP), cardiac function, myocardial lipid peroxidase (LPO) content, and abdominal adiposity. Conclusions: Rodent prenatal CIH exposure, mimicking human maternal OSA, exerts detrimental morphological and cardiovascular effects on developing offspring; the model may provide useful insights of OSA effects in humans.

Potential Therapeutic Applications of MnSODs and SOD-Mimetics

Article

Nov 2017
CHEM-EUR J

Rosalin Bonetta

Natural as well as synthetic antioxidants are constantly being investigated for their efficiency in combatting the effects of oxidative stress, which appears to be the responsible cause of several diseases, which include cancer, central nervous system disorders, ischaemia-reperfusion disorders, cardiovascular conditions and diabetes. Superoxide dismutases (SODs) constitute the ubiquitous antioxidant defenses against oxidative stress that underlies numerous pathological conditions. Therefore, the development of therapeutics aimed at either delivering MnSOD more effectively to target tissues in the body in the form of MnSOD gene therapy, or the synthesis of molecules that mimic the activity of superoxide dismutase is constantly being explored. Such classes that have been developed as SOD mimics include the Mn metalloporphyrins, Mn cyclic polyamines, Mn salen complexes, MnPLED derivatives as well as the nitroxides. Thus far, SOD mimics have shown remarkable efficacy in several animal models suffering from oxidative stress injuries. A promising approach for the future of SOD and SOD mimic therapeutics appears to involve combination treatment of the antioxidants with radiotherapy or chemotherapy.

Computational analysis of interactions of oxidative stress and tetrahydrobiopterin reveals instability in eNOS coupling

Article

Jul 2017

Astragaloside IV improves the isoproterenol-induced vascular dysfunction via attenuating eNOS uncoupling-mediated oxidative stress and inhibiting ROS-NF-κB pathways

Article

Apr 2016

Objective: Oxidative stress and inflammation are regarded as two important triggers of endothelial dysfunction and play pivotal role in progression of vascular damage associated with cardiac hypertrophy. Our previous studies demonstrated that astragaloside IV (AsIV) could protect against cardiac hypertrophy in rats induced by isoproterenol (Iso), but its effects on the aorta are not known. In present study, we aimed to assess the effects of AsIV on Isoinduced vascular dysfunction. Methods: Sprague-Dawley (SD) rats were treated with Iso (10mg/kg/d) alone or in combination with AsIV (50mg/kg/d). Results: Compared with Isotreated alone, AsIV significantly reduced the ratios of heart weight/body weight and left ventricular weight/body weight. AsIV ameliorated the increased vasoconstriction response to phenylephrine induced by Iso and suppressed superoxide anion generation in rat aorta, increased endothelial nitric oxide synthase (eNOS) dimer/monomer ratio and its critical cofactor tetrahydrobiopterin (BH4) content in aorta as well as the NO production in the serum, reduced the plasmatic peroxynitrite (ONOO-). Moreover, in contrast with Isotreatment alone, AsIV decreased the ratio of nuclear-to-cytosolic protein expression of the NF-κB p65 subunit while enhanced its inhibited protein expression of IκB-α, down-regulated mRNA expression of IL-1β, IL-6 and TNF-α of the aorta. Conclusions: The present study suggested that AsIV protects against Isoinduced vascular dysfunction probably via attenuating eNOS uncoupling-mediated oxidative stress and inhibiting ROS-NF-κB pathways.

Role of hypoxia during nephrogenesis

Article

Feb 2016

Mammals develop in a physiologically hypoxic state, and the oxygen tension of different tissues in the embryo is precisely controlled. Deviation from normal oxygenation, such as what occurs in placental insufficiency, can disrupt fetal development. Several studies demonstrate that intrauterine hypoxia has a negative effect on kidney development. As nascent nephrons are forming from nephron progenitors in the nephrogenic zone, they are exposed to varying oxygen tension by virtue of the development of the renal vasculature. Thus, nephrogenesis may be linked to oxygen tension. However, the mechanism(s) by which this occurs remains unclear. This review focuses on what is known about molecular mechanisms active in physiological and pathological hypoxia and their effects on kidney development.

Prenatal hypoxia enhanced angiotensin II-mediated vasoconstriction via increased oxidative signaling in fetal rats

Article

Jan 2016

Toxic factors could cause in utero hypoxia, and prenatal hypoxia (PH) increased incidence of cardiovascular diseases in late life. It is unclear whether/how PH causes vascular injury during fetal life. This study found that PH significantly increased angiotensin II (Ang II)-mediated vessel contractions in fetal thoracic aortas, which was blocked by losartan, not PD123319, indicating that AT1 receptors played a dominant role in the enhanced fetal vasoconstriction following hypoxia. Prenatal hypoxia increased superoxide production and decreased superoxide dismutase (SOD) expression, associated with the enhanced NADPH oxidase (Nox) 4, but not Nox1 or Nox2 in fetal aortas. Ang II-increased vasoconstriction was inhibited by Nox inhibitor apocynin and SOD mimetic blocker tempol. These findings suggested that PH resulted in Ang II/AT1R-mediated fetal vascular hypertensive re-activity via pathways of Nox4-dependent oxidative stress, providing new information regarding the impact of PH on the functional and molecular development of fetal vascular systems.

Defining vascular aging and cardiovascular risk

Article

Jun 2012

Stéphane Laurent

Whereas vascular aging has been identified as an emerging cardiovascular risk factor, definitions of ‘normal’ and ‘early’ vascular aging (EVA) and their precise relationship with cardiovascular risk are currently equivocal. The present review discusses the concept of vascular aging; that structural and functional changes occur in the large arteries with aging; and EVA; that such age-associated changes are accelerated in individuals at increased cardiovascular risk; and their metrics; indeed, in order to provide a definition of when EVA occurs in clinical practice, reference values of normal and accelerated vascular aging are needed. Due to the complex nature of age-associated changes in the large arteries described above, there are different parameters relating to vascular aging which can be measured. These broadly include aortic and carotid stiffening; aortic and carotid lumen dilation; endothelial dysfunction (usually measured via brachial flow-mediated dilatation); and carotid intima-media thickness.

Aging-Induced Phenotypic Changes and Oxidative Stress Impair Coronary Arteriolar Function

Article

Jun 2002

Anna Csiszar

We aimed to elucidate the possible role of phenotypic alterations and oxidative stress in age-related endothelial dysfunction of coronary arterioles. Arterioles were isolated from the hearts of young adult (Y, 14 weeks) and aged (A, 80 weeks) male Sprague-Dawley rats. For videomicroscopy, pressure-induced tone of Y and A arterioles and their passive diameter did not differ significantly. In A, arterioles L-NAME (a NO synthase blocker)–sensitive flow-induced dilations were significantly impaired (Y: 41±8% versus A: 3±2%), which could be augmented by superoxide dismutase (SOD) or Tiron (but not l -arginine or the TXA 2 receptor antagonist SQ29,548). For lucigenin chemiluminescence, O 2 ·− generation was significantly greater in A than Y vessels and could be inhibited with SOD and diphenyliodonium. NADH-driven O 2 ·− generation was also greater in A vessels. Both endothelial and smooth muscle cells of A vessels produced O 2 ·− (shown with ethidium bromide fluorescence). For Western blotting, expression of eNOS and COX-1 was decreased in A compared with Y arterioles, whereas expressions of COX-2, Cu/Zn-SOD, Mn-SOD, xanthine oxidase, and the NAD(P)H oxidase subunits p47 phox , p67 phox , Mox-1, and p22 phox did not differ. Aged arterioles showed an increased expression of iNOS, confined to the endothelium. Decreased eNOS mRNA and increased iNOS mRNA expression in A vessels was shown by quantitative RT-PCR. In vivo formation of peroxynitrite was evidenced by Western blotting, and immunohistochemistry showing increased 3-nitrotyrosine content in A vessels. Thus, aging induces changes in the phenotype of coronary arterioles that could contribute to the development of oxidative stress, which impairs NO-mediated dilations.

Vasodilatory Effect of a Novel Rho-Kinase Inhibitor, DL0805-2, on the rat Mesenteric Artery and its Potential Mechanisms

Article

Aug 2014

Purpose: In the present study, we investigated the vasodilatory effect of a novel scaffold Rho-kinase inhibitor, DL0805-2, on isolated rat arterial rings including mesenteric, ventral tail, and renal arteries. We also examined the potential mechanisms of its vasodilatory action using mesenteric artery rings. Methods: A DMT multiwire myograph system was used to test the tension of isolated small arteries. Several drugs were employed to verify the underlying mechanisms. Results: DL0805-2 (10(-7)-10(-4) M) inhibited KCl (60 mM)-induced vasoconstriction in three types of small artery rings (pEC50: 5.84 ± 0.03, 5.39 ± 0.03, and 5.67 ± 0.02 for mesenteric, renal, and ventral tail artery rings, respectively). Pre-incubation with DL0805-2 (1, 3, or 10 μM) attenuated KCl (10-60 mM) and angiotensin II (AngII; 10(-6) M)-induced vasoconstriction in mesenteric artery rings. The relaxant effect on the rat mesenteric artery was partially endothelium-dependent (pEC50: 6.02 ± 0.05 for endothelium-intact and 5.72 ± 0.06 for endothelium-denuded). The influx and release of Ca(2+) were inhibited by DL0805-2. In addition, the increased phosphorylation levels of myosin light chain (MLC) and myosin-binding subunit of myosin phosphatase (MYPT1) induced by AngII were blocked by DL0805-2. However, DL0805-2 had little effect on K(+) channels. Conclusions: The present results demonstrate that DL0805-2 has a vasorelaxant effect on isolated rat small arteries and may exert its action through the endothelium, Ca(2+) channels, and the Rho/ROCK pathway.

Evidence of oxidative stress and mitochondrial respiratory chain dysfunction in an in vitro model of sepsis-induced kidney injury

Article

Oct 2014
BBA-BIOENERGETICS

To investigate the role of oxidative stress and/or mitochondrial impairment in the occurrence of acute kidney injury (AKI) during sepsis, we developed a sepsis-induced in vitro model using proximal tubular epithelial cells exposed to a bacterial endotoxin (lipopolysaccharide, LPS). This investigation has provided key features on the relationship between oxidative stress and mitochondrial respiratory chain activity defects. LPS treatment resulted in an increase in the expression of inducible nitric oxide synthase (iNOS) and NADPH oxidase 4 (NOX-4), suggesting the cytosolic overexpression of nitric oxide and superoxide anion, the primary reactive nitrogen species (RNS) and reactive oxygen species (ROS). This oxidant state seemed to interrupt mitochondrial oxidative phosphorylation by reducing cytochrome c oxidase activity. As a consequence, disruptions in the electron transport and the proton pumping across the mitochondrial inner membrane occurred, leading to a decrease of the mitochondrial membrane potential, a release of apoptotic-inducing factors and a depletion of adenosine triphosphate. Interestingly, after being targeted by RNS and ROS, mitochondria became in turn producer of ROS, thus contributing to increase the mitochondrial dysfunction. The role of oxidants in mitochondrial dysfunction was further confirmed by the use of iNOS inhibitors or antioxidants that preserve cytochrome c oxidase activity and prevent mitochondrial membrane potential dissipation. These results suggest that sepsis-induced AKI should not only be regarded as failure of energy status but also as an integrated response, including transcriptional events, ROS signaling, mitochondrial activity and metabolic orientation such as apoptosis.

High-sucrose diets in pregnancy alter angiotensin II-mediated pressor response and microvessel tone via the PKC/Cav1.2 pathway in rat offspring

Article

May 2014
Hypertens Res

This study determines the influence of a prenatal high-sucrose (HS) diet on angiotensin II (Ang II)-mediated pressor response and determine the underlying mechanism. Pregnant rats were provided with a 20% sucrose solution diet throughout gestation. Blood pressure and vascular response to Ang II were measured in 5-month-old adult offspring. Currents of L-type Ca(2+) channels (Cav1.2) were measured in smooth muscle cells of small mesenteric arteries from the offspring. Ang II-mediated pressor response was higher in the offspring exposed to prenatal high sugar compared with the control. In mesenteric arteries from the HS offspring, AT1 receptors (AT1R), not AT2 receptors, mediated the increased vasoconstriction; protein kinase C (PKC) antagonist GF109203X suppressed the Ang II-increased vasoconstriction; PKC agonist phorbol 12,13-dibutyrate produced a greater contractile response that was reversed by the Cav1.2 antagonist nifedipine. The expression of PKCα was increased, whereas PKCδ was unchanged; KCl-induced vasoconstriction was stronger and was suppressed by nifedipine; nifedipine also reduced the enhanced vasoconstriction by Ang II. In addition, the Cav1.2 of smooth muscle cells in mesenteric arteries from the HS offspring showed larger current density, although its expression was unchanged. The data suggest that a HS diet during pregnancy alters Ang II-mediated pressor response and microvessel tone acting through the PKC/Cav1.2 pathway in the offspring that may in part be because of alterations in AT1Rs, PKCα and Cav1.2.Hypertension Research advance online publication, 8 May 2014; doi:10.1038/hr.2014.94.

Oxidative stress, neurodegeneration, and the balance of protein degradation and protein synthesis

Data

Sep 2012

a b s t r a c t Oxidative stress occurs in a variety of disease settings and is strongly linked to the development of neuron death and neuronal dysfunction. Cells are equipped with numerous pathways to prevent the genesis, as well as the consequences, of oxidative stress in the brain. In this review we discuss the various forms and sources of oxidative stress in the brain and briefly discuss some of the complexities in detecting the presence of oxidative stress. We then focus the review on the interplay between the diverse cellular proteolytic pathways and their roles in regulating oxidative stress in the brain. Additionally, we discuss the involvement of protein synthesis in regulating the downstream effects of oxidative stress. Together, these components of the review demonstrate that the removal of damaged proteins by effective proteolysis and the synthesis of new and protective proteins are vital in the preservation of brain homeostasis during periods of increased levels of reactive oxygen species. Last, studies from our laboratory and others have demonstrated that protein synthesis is intricately linked to the rates of protein degradation, with impairment of protein degradation sufficient to decrease the rates of protein synthesis, which has important implications for successfully responding to periods of oxidative stress. Specific neurodegenerative diseases, including Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, and stroke, are discussed in this context. Taken together, these findings add to our understanding of how oxidative stress is effectively managed in the healthy brain and help elucidate how impairments in proteolysis and/or protein synthesis contribute to the development of neurodegeneration and neuronal dysfunction in a variety of clinical settings. & 2012 Published by Elsevier Inc.

Nitric oxide synthase inhibition and oxidative stress in cardiovascular diseases: Possible therapeutic targets?

Article

Jul 2013

Fetal programming of cardiovascular disease: New causes and underlying mechanisms

Article

Sep 2012
Rev Med Suisse

There exists an association between pathologic events occurring during early life and the development of cardiovascular disease in adulthood. For example, transient perinatal hypoxemia predisposes to exaggerated hypoxic pulmonary hypertension and preeclampsia predisposes the offspring to pulmonary and systemic endothelial dysfunction later in life. The latter finding offers a scientific basis for observations demonstrating an increased risk for premature cardiovascular morbidity in this population. Very recently, we showed that offspring of assisted reproductive technologies also display generalized vascular dysfunction and early arteriosclerosis. Studies in animal models have provided evidence that oxidative stress and/or epigenetic alterations play an important pathophysiological role in the fetal programming of cardiovascular disease.

Alpha Lipoic Acid Treatment Improved Endothelium-dependent Relaxation in Diabetic Rat Aorta

Article

May 2011
YAKUGAKU ZASSHI

The aim of this study was to ascertain the effects of α-lipoic acid (ALA) treatment on relaxant responses of acetylcholine (ACh) and isoprenaline (ISO) in aortic rings precontracted with serotonin (5-HT, 10(-6) M) obtained from streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in the rats by 50 mg/kg streptozotocin (STZ) via an intraperitoneal injection. Rat body and aorta weights were measured. The isometric tension to ACh (10(-9)-3×10(-6) M) and ISO (10(-9)-10(-4) M) of 5-HT-precontracted diabetic and non-diabetic rat (control), diabetic-ALA-treated, and ALA-treated aortas, in organ baths were recorded. Six weeks after STZ treatment blood glucose was elevated compared to control rats. In aortic rings from diabetic rats ACh and ISO-induced relaxations were impaired whereas endothelium-independent relaxation to sodium nitroprusside (SNP) was unaffected. ALA (100 mg/kg/day) treatment for 5 weeks enhanced ACh and ISO-induced relaxation in diabetic aortas. This recovering effect was via NO because prevented by incubating the vessels with N(G)-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). It may be assumed that ALA treatment in vivo, can protect against impaired vascular responsiveness in STZ-induced diabetic rats.

Intrinsic nitric oxide and superoxide production regulates descending vasa recta contraction

Article

Nov 2010
AM J PHYSIOL-RENAL

Descending vasa recta (DVR) are 12- to 15-μm microvessels that supply the renal medulla with blood flow. We examined the ability of intrinsic nitric oxide (NO) and reactive oxygen species (ROS) generation to regulate their vasoactivity. Nitric oxide synthase (NOS) inhibition with N(ω)-nitro-l-arginine methyl ester (l-NAME; 100 μmol/l), or asymmetric N(G),N(G)-dimethyl-l-arginine (ADMA; 100 μmol/l), constricted isolated microperfused DVR by 48.82 ± 4.34 and 27.91 ± 2.91%, respectively. Restoring NO with sodium nitroprusside (SNP; 1 mmol/l) or application of 8-Br-cGMP (100 μmol/l) reversed DVR vasoconstriction by l-NAME. The superoxide dismutase mimetic Tempol (1 mmol/l) and the NAD(P)H inhibitor apocynin (100, 1,000 μmol/l) also blunted ADMA- or l-NAME-induced vasoconstriction, implicating a role for concomitant generation of ROS. A role for ROS generation was also supported by an l-NAME-associated rise in oxidation of dihydroethidium that was prevented by Tempol or apocynin. To test whether H(2)O(2) might play a role, we examined its direct effects. From 1 to 100 μmol/l, H(2)O(2) contracted DVR whereas at 1 mmol/l it was vasodilatory. The H(2)O(2) scavenger polyethylene glycol-catalase reversed H(2)O(2) (10 μmol/l)-induced vasoconstriction; however, it did not affect l-NAME-induced contraction. Finally, the previously known rise in DVR permeability to (22)Na and [(3)H]raffinose that occurs with luminal perfusion was not prevented by NOS blockade. We conclude that intrinsic production of NO and ROS can modulate DVR vasoactivity and that l-NAME-induced vasoconstriction occurs, in part, by modulating superoxide concentration and not through H(2)O(2) generation. Intrinsic NO production does not affect DVR permeability to hydrophilic solutes.

Nitric Oxide-mediated Dilation of Arterioles to Intraluminal Administration of Aldosterone

Article

Sep 2009
J CARDIOVASC PHARM

The nature of the rapid action of aldosterone on blood vessels, whether endothelium-dependent dilation or smooth muscle-dependent constriction is predominant, is still in dispute. In this study, we administered aldosterone intraluminally or extraluminally to isolated mesenteric and cerebral arterioles of male Wistar rats. Extraluminal administration of aldosterone (10(-11) or 10(-7) M) elicited a transient vasodilatation. The peak response appeared at approximately 5 minutes. In contrast, intraluminal administration of aldosterone elicited a greater and sustained dilation. When aldosterone (10(-12)-10(-7) M) was administered extraluminally in a cumulative manner, dose-dependent vasodilator responses were elicited, except a reduced dilation was observed to 10(-7) M aldosterone. The dilations were significantly inhibited by spironolactone (10(-7) M), a mineralocorticoid receptor antagonist or Nomega-nitro-l-arginine methyl ester (3 x 10(-4) M), a NO synthesis inhibitor. In endothelium-denuded vessels, extraluminal aldosterone induced a dose-dependent vasoconstrictor response. Scavenging superoxide with Tempol (10(-4) M) sustained the extraluminal aldosterone (10(-11) or 10(-7) M)-induced dilation, whereas inhibition of NO synthesis or removal of the endothelium abolished intraluminal aldosterone-induced dilation. Dilation to 10(-7) M aldosterone was significantly enhanced after inhibition of NAD(P)H-oxidase with apocynin (10(-5) M). Furthermore, in the presence of endothelial dysfunction, induced by chronic inhibition of NO synthesis, intraluminal administration of aldosterone failed to dilate the arterioles. We conclude that in physiological conditions, acute elevation of aldosterone will evoke mainly an endothelium-dependent NO-mediated dilation.

Arterial Aging and Subclinical Arterial Disease are Fundamentally Intertwined at Macroscopic and Molecular Levels

Article

Jun 2009

The structure and function of arteries change throughout a lifetime. Age is the dominant risk factor for hypertension, coronary heart disease, congestive heart failure, and stroke. The cellular/molecular proinflammatory alterations that underlie arterial aging are novel putative candidates to be targeted by interventions aimed at attenuating arterial aging as a major risk factor for cardiovascular diseases. This review provides a landscape of central arterial aging and age-disease interactions, integrating perspectives that range from humans to molecules, with the goal that future therapies for cardiovascular diseases, such as hypertension, also will target the prevention or amelioration of unsuccessful arterial aging.

Neonatal Oxygen Exposure in Rats Leads to Cardiovascular and Renal Alterations in Adulthood

Article

Nov 2008
Hypertension

Long-term vascular and renal consequences of neonatal oxidative injury are unknown. Using a rat model, we sought to investigate whether vascular function and blood pressure are altered in adult rats exposed to hyperoxic conditions as neonates. We also questioned whether neonatal O(2) injury causes long-term renal damage, important in the pathogenesis of hypertension. Sprague-Dawley pups were kept with their mother in 80% O(2) or room air from days 3 to 10 postnatal, and blood pressure was measured (tail cuff) from weeks 7 to 15. Rats were euthanized, and vascular reactivity (ex vivo carotid rings), oxidative stress (lucigenin chemiluminescence and dihydroethidium fluorescence), microvascular density (tibialis anterior muscle), and nephron count were studied. In male and female rats exposed to O(2) as newborns, systolic and diastolic blood pressures were increased (by an average of 15 mm Hg); ex vivo, maximal vasoconstriction (both genders) and sensitivity (males only) specific to angiotensin II were increased; endothelium-dependant vasodilatation to carbachol but not to NO-donor sodium nitroprussiate was impaired; superoxide dismutase analogue prevented vascular dysfunction to angiotensin II and carbachol; vascular superoxide production was higher; and capillary density (by 30%) and number of nephrons per kidney (by 25%) were decreased. These data suggest that neonatal hyperoxia leads in the adult rat to increased blood pressure, vascular dysfunction, microvascular rarefaction, and reduced nephron number in both genders. Our findings support the hypothesis of developmental programming of adult cardiovascular and renal diseases and provide new insights into the potential role of oxidative stress in this process.

Karlsson K & Marklund SL.Extracellular superoxide dismutase in the vascular system of mammals. Biochem J 255: 223−228

Article

Nov 1988

Plasma extracellular superoxide dismutase (EC-SOD) from the pig, cat, rabbit, guinea pig and mouse was found to be heterogeneous with regard to heparin affinity and could be separated into three fractions: A without affinity, B with weak affinity and C with relatively high affinity. Rat plasma EC-SOD was deviant and contained only A and B fractions. There were very large interspecies differences in total plasma EC-SOD activity and in division of the activity between the different fractions. Intravenous injection of heparin resulted in the pig, dog, cat, rabbit, guinea pig and mouse in a prompt increase in the plasma SOD activity. The increase was due to release of EC-SOD C to plasma, most probably from endothelial cell surfaces. In the rat, heparin induced no increase in plasma SOD activity, apparently because of the absence of EC-SOD C in this species. The relative heparin-induced increase in plasma EC-SOD C varied between 2 and 11 in the different species and was distinctly correlated with the heparin affinity of EC-SOD C in the particular species. Apparently the EC-SOD C, present in the vasculature, forms an equilibrium between plasma and endothelium, whereas EC-SOD A and B primarily exist in plasma. The wide diversity of EC-SOD in the vascular system of mammals with regard to total amount, division into fractions and distribution between plasma and endothelium indicates that the pathogenic potential of superoxide radicals in the extracellular space might vary much between species.

Heparin-induced release of extracellular superoxide dismutase to human blood plasma

Article

Mar 1987

Extracellular superoxide dismutase (SOD) has previously been shown to be the major SOD isoenzyme in extracellular fluids. Upon chromatography on heparin-Sepharose it was separated into three fractions: A, without affinity; B, with intermediate affinity; and C, with relatively strong heparin affinity. Intravenous injection of heparin leads to a prompt increase in plasma extracellular-superoxide-dismutase (EC-SOD) activity. Heparin induces no release of EC-SOD from blood cells, nor does it activate EC-SOD in plasma, indicating that the source of the released enzyme is the endothelial-cell surfaces. No distinct saturation could be demonstrated in a dose-response curve up to 200 i.u. of heparin per kg body weight, showing that the releasing potency of heparin is lower for EC-SOD than for previously investigated heparin-released factors. Chromatography of human plasma on heparin-Sepharose shows nearly equal amounts of EC-SOD fractions A, B and C. Heparin induces specifically the release of fraction C. The findings point to the existence of an equilibrium of EC-SOD fraction C between the plasma phase and endothelial-cell surfaces. The major part of EC-SOD in the vasculature seems to be located on endothelial-cell surfaces.

Fetal Nutrition and Cardiovascular Disease in Adult Life

Article

May 1993

Babies who are small at birth or during infancy have increased rates of cardiovascular disease and non-insulin-dependent diabetes as adults. Some of these babies have low birthweights, some are small in relation to the size of their placentas, some are thin at birth, and some are short at birth and fail to gain weight in infancy. This paper shows how fetal undernutrition at different stages of gestation can be linked to these patterns of early growth. The fetuses' adaptations to undernutrition are associated with changes in the concentrations of fetal and placental hormones. Persisting changes in the levels of hormone secretion, and in the sensitivity of tissues to them, may link fetal undernutrition with abnormal structure, function, and disease in adult life.

Pharmacokinetics of extracellular-superoxide dismutase in the vascular system

Article

Mar 1993
FREE RADICAL BIO MED

Extracellular-superoxide dismutase C (EC-SOD C) is a secretory tetrameric Cu- and Zn-containing glycoprotein which has high affinity for heparin and heparan sulfate. Upon intravenous injection into rabbits, recombinant human (rh) EC-SOD C was found to be rapidly 97-98% sequestered to the vascular wall, forming an equilibrium with the plasma phase. Recombinant EC-SOD truncation variants with reduced, T216, and without, T213, heparin affinity were found to be sequestered to a reduced extent and not at all, respectively, establishing the importance of the heparin affinity for this behaviour. The halflife of rhEC-SOD C in the vasculature was of the order of 20 h. Injection of large doses resulted in saturation of the binding of rhEC-SOD C to the vascular wall. Scatchard analysis revealed a heterogeneity in affinity of the ligands on the vascular wall. The maximal binding capacity was very high. The equilibration of rhEC-SOD C to the vascular wall of an organ, clamped during enzyme injection, and the primary equilibration phase was studied by comparing binding to a clamped and reperfused kidney with binding to the contralateral control kidney. rhEC-SOD C injected in a low dose was found to equilibrate very slowly to the reperfused kidney with a halftime of about 2 h. With higher rhEC-SOD C doses, at which evidence for saturation is seen, and with the variant rhEC-SOD with reduced heparin affinity. T216, very rapid equilibrations were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxidative Stress: Oxidants and Antioxidants

Article

Apr 1997

Helmut Sies

An imbalance between oxidants and antioxidants in favour of the oxidants, potentially leading to damage, is termed 'oxidative stress'. Oxidants are formed as a normal product of aerobic metabolism but can be produced at elevated rates under pathophysiological conditions. Antioxidant defense involves several strategies, both enzymatic and non-enzymatic. In the lipid phase, tocopherols and carotenes as well as oxy-carotenoids are of interest, as are vitamin A and ubiquinols. In the aqueous phase, there are ascorbate, glutathione and other compounds. In addition to the cytosol, the nuclear and mitochondrial matrices and extracellular fluids are protected. Overall, these low molecular mass antioxidant molecules add significantly to the defense provided by the enzymes superoxide dismutase, catalase and glutathione peroxidases.

Demonstration of fetal coronary blood flow by Doppler ultrasound in relation to arterial and venous flow velocity waveforms and perinatal outcome - The 'heart-sparing effect'

Article

Apr 1997

This longitudinal observational study evaluates the stage at which coronary flow can be visualized by color-coded and pulsed wave Doppler sonography in fetuses with normal cardiac anatomy. Fetal biometry, echocardiography and Doppler examination of the umbilical and middle cerebral arteries, ductus venosus, inferior vena cava and umbilical vein were performed in 109 cases. Fetuses were divided into five groups based on the Doppler examination of the umbilical artery, birth weight and the ability to visualize coronary blood flow. Coronary blood flow was identified in six of 55 fetuses with normal growth who had normal Doppler studies and perinatal outcome. In these, visualization of coronary blood flow was possible after 31 weeks' gestation at a median gestational age of 37 weeks. Coronary blood flow was also visualized in ten of 54 fetuses with severe intrauterine growth retardation and highly pathological flow velocity waveforms in all vessels soon after a significant increase of venous indices in the inferior vena cava and ductus venosus. In these cases, coronary blood flow was identified at a significantly earlier gestational age (median 27 weeks). These fetuses had a poor perinatal outcome (average birth weight less than 3rd centile, mortality rate 50%, significantly lower umbilical artery blood pH and Apgar scores after 1 and 5 min). Intrauterine fetal death occurred in five fetuses after a median of 3.5 days following visualization of coronary blood flow. Median coronary peak blood flow velocities in the right coronary artery were higher in intrauterine growth-retarded than appropriate-for-gestational-age fetuses.

Prenatal hypoxia affected endothelium-dependent vasodilation in mesenteric arteries of aged offspring via increased oxidative stress

Abstract

No full-text available

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