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The Protective Effect of Bergamot Oil Extract on Lecitine-like OxyLDL Receptor-1 Expression in Balloon Injury-related Neointima Formation
Abstract
Lectin-like oxyLDL receptor-1 (LOX-1) has recently been suggested to be involved in smooth muscle cell (SMC) proliferation and neointima formation in injured blood vessels. This study evaluates the effect of the nonvolatile fraction (NVF), the antioxidant component of bergamot essential oil (BEO), on LOX-1 expression and free radical generation in a model of rat angioplasty. Common carotid arteries injured by balloon angioplasty were removed after 14 days for histopathological, biochemical, and immunohistochemical studies. Balloon injury led to a significant restenosis with SMC proliferation and neointima formation, accompanied by increased expression of LOX-1 receptor, malondialdehyde and superoxide formation, and nitrotyrosine staining. Pretreatment of rats with BEO-NVF reduced the neointima proliferation together with free radical formation and LOX-1 expression in a dose-dependent manner. These results suggest that natural antioxidants may be relevant in the treatment of vascular disorders in which proliferation of SMCs and oxyLDL-related endothelial cell dysfunction are involved.
... Experimental and epidemiological studies have demonstrated that bergamot polyphenolic fraction (BPF) ameliorates serum lipemic profile and normalizes blood pressure in patients suffering from MS. Previous scientific evidence obtained with Citrus flavonoids and other non-nutritive constituents of Citrus fruits, explain their beneficial effects and to further clarify some mechanisms involved in MS [12,13,16]. ...
... Given the structural similarity to HMG-CoA reductase substrate brutieridine and melitidine have been shown to possess statin-like properties, by selective inhibition of HMG-CoA reductase [29]. The direct action of BPF on HMG-CoA reductase activity has been confirmed by a significant reduction of the end product of HMG-CoA reductase activity, mevalonate (MVA), detected in the urine of patients under BPF treatment [12,13,16,30]. ...
... Oxidative stress and LOX-1 expression are early events in the biochemical changes that can be found in vascular tissue after induction of injury, and restoring antioxidant status by treating rats with BPF reduces restenosis of injured arterial vessels by counteracting free radical formation and LOX-1 expression [16]. ...
Metabolic syndrome (MS) represents a clustering of risk factors related to an elevated incidence of cardiovascular disease (CVD) and type 2 diabetes. Despite the possibility of multiple pharmacological interventions to treat metabolic changes related to MS, these therapeutic strategies often exhibit several side effects and inadequately prevents CVD. Among nutraceutical compounds presenting potential efficacy in this regard, bergamot polyphenols, via their multi-action properties, have been shown to positively modulate several mechanisms involved in MS suggesting their benefits as therapy. The purpose of this review is to discuss the beneficial effects of bergamot polyphenols providing a new therapeutic approach in the treatment of MS.
... Studies showed that bergamot (in particular the bergamot polyphenolic fraction; BPF) has a higher concentration of polyphenols compared to other citrus fruits; in fact, it contains 5 main flavonoids namely neoeriocitrin, naringin, neohesperidin, melitidin and brutieridin [32,[52][53][54]. ...
... Moreover, it has been observed that administration of BPF, hydroxytyrosol, oleuropein or resveratrol was able to attenuate the allodynia and the hyperalgesia through the removal of ROS/RNS in animal models of pain of different etiologies [19,21,31,32,54]. ...
Neuropathic pain is a chronic painful disease. Data have shown that reactive oxygen species (ROS) are implicated in chronic pain. Particularly, the enhanced ROS production alters the mitochondrial genome and proteome through the accumulation of lipid peroxidation products, such as 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). Sirtuin 3 (SIRT3) is a mitochondrial protein and its activity can reduce ROS levels by modulating key antioxidant enzymes, such as manganese superoxide dismutase (MnSOD). Here, we evaluated the role of SIRT3 in the maintenance of basal levels of ROS in a model of chronic constriction injury (CCI) of the sciatic nerve and the protective effects of a natural antioxidant, the bergamot polyphenolic fraction (BPF). Rats were exposed to CCI of the sciatic nerve in the presence or absence of BPF (25–75 mg/kg). Level of acetylation, post-translational modulation on cysteine residues of proteins by HNE and SIRT3 activation, were detected in the spinal cord through western blotting, WES methodology and enzymatic assays. Our results reported that SIRT3 carbonylation and therefore its inactivation contributes to mitochondrial MnSOD hyperacetylation during CCI induced neuropathic pain in rats. In particular, we have demonstrated a close relation between oxidative stress, hyperalgesia, allodynia and sirtuins inactivation reverted by BPF administration.
... The antioxidant effect of bergamot was initially observed by analyzing the potential activity of the non-volatile fraction of the bergamot essential oil (BEO-NVF) in an experimental model of neointima hyperplasia. Mollace et al. identified the highly significant effect of the antioxidant component of BEO-NVF on LOX-1 expression and ROS generation in a model of rat carotid artery injury [111]. The results have shown that balloon injury is associated with smooth muscle cell proliferation and neo-intima formation causing re-stenosis. ...
... These cells also reveal an increase in LOX-1 expression and generation of ROS. Interestingly, pre-treatment of rats with BEO-NVF decreases neo-intima formation, LOX-1 expression and ROS generation as well as the degree of stenosis [111]. The natural antioxidant and LOX-1 modulating properties of BEO-NVF appear to be promising for use in MetS to decrease endothelial dysfunction, smooth muscle cell proliferation and inflammation, all of which bridge the gap between MetS and ASCVD. ...
Metabolic syndrome (MetS) represents a set of clinical findings that include visceral adiposity, insulin-resistance, high triglycerides (TG), low high-density lipoprotein cholesterol (HDL-C) levels and hypertension, which is linked to an increased risk of developing type 2 diabetes mellitus (T2DM) and atherosclerotic cardiovascular disease (ASCVD). The pathogenesis of MetS involves both genetic and acquired factors triggering oxidative stress, cellular dysfunction and systemic inflammation process mainly responsible for the pathophysiological mechanism. In recent years, MetS has gained importance due to the exponential increase in obesity worldwide. However, at present, it remains underdiagnosed and undertreated. The present review will summarize the pathogenesis of MetS and the existing pharmacological therapies currently used and focus attention on the beneficial effects of natural compounds to reduce the risk and progression of MetS. In this regard, emerging evidence suggests a potential protective role of bergamot extracts, in particular bergamot flavonoids, in the management of different features of MetS, due to their pleiotropic anti-oxidative, anti-inflammatory and lipid-lowering effects.
... The extract of bergamot (Citrus bergamia) is rich in flavonoids that have antioxidant, anti-inflammatory, as well as lipid-lowering properties [25]. The hydroxy methylglutaryl-flavonones contained in the Citrus bergamia, such as hesperetin, naringenin brutieridine, and melitidine, have specific effects on lipid profile inhibiting, as the statin, the enzyme HMG-CoA reductase, and the activity of AcylCo-enzymeA Cholesterol-Acyl-Transferase (ACAT), then reducing the assembly of VLDL and LDL lipoproteins [26]. ...
... Citrus bergamia can therefore play an important role in preventing vascular damage due to proliferation of smooth muscle cells and dysfunction of endothelial cells. A study of an angioplasty model in rats showed that pretreatment with Citrus bergamia reduced neointima proliferation, free radical formation, and LDL-ox receptor expression [25]. Toth and colleagues [28] recently investigated the effects of Citrus bergamia flavonoids supplementation on cardio-metabolic risk in dyslipidemic subjects, demonstrating that this supplementation significantly reduced plasma lipids and improved the lipoprotein profile. ...
Nutritional approaches to improve dyslipidemias have been recently developed, but evidences on different medical foods are often incomplete. The main aim of our study was to evaluate the effects on endothelial function, lipid profile, and glucose metabolism of two different combinations of nutraceuticals, first one containing Bergavit (200 mg Citrus bergamia), Omega-3 (400 mg), Crominex 3+ (10 mcg trivalent chromium), and red yeast rice (100 mg; 5 mg monacolin K) and second one containing red yeast rice (200 mg; 3 mg monacolin K), Berberine (500 mg), Astaxanthin (0.5 mg), folic acid (200 mcg), Coenzyme Q10 (2 mg), and Policosanol (10 mg). Fifty subjects affected by dyslipidemia not requiring statin treatment were enrolled in this randomized, blind, controlled trial and submitted to blood sampling for lipid and glucose profiles and instrumental evaluation of endothelial function before and after 6 weeks of treatment with nutraceuticals. Both nutraceutical combinations improved the lipid profile; the nutraceutical containing 5 mg of monacolin K, 200 mg of the extract Citrus bergamia , 400 mg of Omega-3, and 10 mcg of trivalent chromium entailed a significant improvement of endothelial function with enhanced cholesterol lowering effect. In conclusion, this study confirms the positive effect of functional food on lipid profile and endothelial function in absence of major undesirable effects.
... Mollace and colleagues studied the effect of the antioxidant component of bergamot oil on LOX-1 expression and free-radical generation on carotid injury in the rat. 40 In the study, balloon injury was associated with smooth muscle cell proliferation, neointima formation, ROS generation, and increased LOX-1 expression. Pretreatment of these rats with bergamot essential oil decreased neointima formation, LOX-1 expression, and free-radical generation, reducing the degree of stenosis. ...
... Pretreatment of these rats with bergamot essential oil decreased neointima formation, LOX-1 expression, and free-radical generation, reducing the degree of stenosis. 40 Other natural compounds such as procyanins, 6-shogoal procyanins, and flavonoids have also been associated with antioxidant properties that may be beneficial for the management of MetS. ...
Metabolic syndrome (MetS) represents a cluster of metabolic abnormalities that include hypertension, central obesity, insulin resistance, and atherogenic dyslipidemia, and is strongly associated with an increased risk for developing diabetes and atherosclerotic and nonatherosclerotic cardiovascular disease (CVD). The pathogenesis of MetS involves both genetic and acquired factors that contribute to the final pathway of inflammation that leads to CVD. MetS has gained significant importance recently due to the exponential increase in obesity worldwide. Early diagnosis is important in order to employ lifestyle and risk factor modification. Here, we review the epidemiology and pathogenesis of MetS, the role of inflammation in MetS, and summarize existing natural therapies for MetS.
... These events are modulated by the overexpression of the lectin-like oxidized LDL (LOX-1), a scavenger receptor which selectively internalizes oxyLDL in EC [9]. LOX-1 is highly modulated by stimuli which have been shown to play a role in the development and progression of atherosclerosis, such as cytokines, mechanical forces, angiotensin II, oxidative stress and directly by the occurrence of oxyLDL [7,8,10]. At the final stages of atherogenesis, clear evidence shows that oxyLDL, possibly via overexpression of LOX-1, contributes to the development of apoptotic cell death of endothelial cells [11,12]. ...
... Moreover, recent evidence proposes a direct correlation between LOX-1 activation and free radical-induced apoptosis of endothelial cells. On the other hand, the modulation of oxidative stress via both endogenous as well as exogenous antioxidants prevents apoptotic cell death, an effect which occurs via concomitant modulation of LOX-1 [6,10,22]. This has been proven by using pterostilbene, a naturally occurring analogue of antioxidant resveratrol, which has been shown to inhibit oxyLDL-induced apoptosis of endothelial cells from the umbilical vein by down-regulating LOX-1 expression and thereby suppressing intracellular oxidative stress [32]. ...
... Furthermore, in a rat model of angioplasty, the pretreatment with bergamot essential oil reduced smooth muscle cell proliferation and neointima formation. This effect was associated with reduced free radical formation and reduced expression of LOX-1, the receptor for oxidized low-density lipoprotein [48]. ...
High salt load is a known noxious stimulus for vascular cells and a risk factor for cardiovascular diseases in both animal models and humans. The stroke-prone spontaneously hypertensive rat (SHRSP) accelerates stroke predisposition upon high-salt dietary feeding. We previously demonstrated that high salt load causes severe injury in primary cerebral endothelial cells isolated from SHRSP. This cellular model offers a unique opportunity to test the impact of substances toward the mechanisms underlying high-salt-induced vascular damage. We tested the effects of a bergamot polyphenolic fraction (BPF) on high-salt-induced injury in SHRSP cerebral endothelial cells. Cells were exposed to 20 mM NaCl for 72 h either in the absence or the presence of BPF. As a result, we confirmed that high salt load increased cellular ROS level, reduced viability, impaired angiogenesis, and caused mitochondrial dysfunction with a significant increase in mitochondrial oxidative stress. The addition of BPF reduced oxidative stress, rescued cell viability and angiogenesis, and recovered mitochondrial function with a significant decrease in mitochondrial oxidative stress. In conclusion, BPF counteracts the key molecular mechanisms underlying high-salt-induced endothelial cell damage. This natural antioxidant substance may represent a valuable adjuvant to treat vascular disorders.
... The antioxidant effect of bergamot was first discovered by testing the activity of the nonvolatile fraction of the bergamot essential oil (BEO-NVF) in an experimental model of neointima hyperplasia. The results showed that the antioxidant effect is mediated by the downregulation of Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) receptor and ROS formation that led to a regression of artery injury [105]. The restoration of the total oxidative status has also been confirmed after oral administration of the bergamot polyphenol fraction (BPF), derived from juice and albedo, in an animal model of metabolic associated fatty liver disease (MAFLD). ...
Diabetes is a complex chronic disease, and among the affected patients, cardiovascular disease (CVD)is the most common cause of death. Consequently, the evidence for the cardiovascular benefit of glycaemic control may reduce long-term CVD rates. Over the years, multiple pharmacological approaches aimed at controlling blood glucose levels were unable to significantly reduce diabetes-related cardiovascular events. In this view, a therapeutic strategy combining SGLT2 inhibitors and plant extracts might represent a promising solution. Indeed, countering the main cardiometabolic risk factor using plant extracts could potentiate the cardioprotective action of SGLT2 inhibitors. This review highlights the main molecular mechanisms underlying these beneficial effects that could contribute to the better management of diabetic patients.
... properties-↓ ROS formation-↓ lectin-like LDL receptor-1 expression [208] Grapes (Vitus vinifera) Active ingredient: resveratrol, (3,5,4 -trihydroxystilbene) ...
Metabolic syndrome (MetS) forms a cluster of metabolic dysregulations including insulin resistance, atherogenic dyslipidemia, central obesity, and hypertension. The pathogenesis of MetS encompasses multiple genetic and acquired entities that fall under the umbrella of insulin resistance and chronic low-grade inflammation. If left untreated, MetS is significantly associated with an increased risk of developing diabetes and cardiovascular diseases (CVDs). Given that CVDs constitute by far the leading cause of morbidity and mortality worldwide, it has become essential to investigate the role played by MetS in this context to reduce the heavy burden of the disease. As such, and while MetS relatively constitutes a novel clinical entity, the extent of research about the disease has been exponentially growing in the past few decades. However, many aspects of this clinical entity are still not completely understood, and many questions remain unanswered to date. In this review, we provide a historical background and highlight the epidemiology of MetS. We also discuss the current and latest knowledge about the histopathology and pathophysiology of the disease. Finally, we summarize the most recent updates about the management and the prevention of this clinical syndrome.
... BEO, the most important product obtained by bergamot fruits and used mostly in perfume industry, is a phytocomplex composed by a volatile fraction, (almost the 95% of the total) that consists of monoterpenes like limonene, linalool, linalyl acetate, α-pinene, β-pinene, and γ-terpinene, and a non-volatile one, that consists mostly of coumarins and psoralens, like bergapten, bergamottin and citropten [35]. It was studied for its application in aromatherapy [36], as well as for its antimicrobial [15], cardioprotective [37], and anticancer properties [7,38]. ...
The plant kingdom has always been a treasure trove for valuable bioactive compounds, and Citrus fruits stand out among the others. Bergamottin (BRG) and 5-geranyloxy-7-methoxycoumarin (5-G-7-MOC) are two coumarins found in different Citrus species with well-acknowledged pharmacological properties. Previously, they have been claimed to be relevant in the anti-proliferative effects exerted by bergamot essential oil (BEO) in the SH-SY5Y human neuroblastoma cells. This study was designed to verify this assumption and to assess the mechanisms underlying the anti-proliferative effect of both compounds. Our results demonstrate that BRG and 5-G-7-MOC are able to reduce the proliferation of SH-SY5Y cells, inducing apoptosis and increasing cell population in sub-G0/G1 phase. Moreover, we demonstrated the pro-oxidant activity of the two coumarins that increased reactive oxygen species and impaired mitochondrial membrane potential. From a molecular point of view, BRG and 5-G-7-MOC were able to modulate apoptosis related factors at both protein and gene levels. Lastly, we evaluated the synergistic effect of their combination, finding that the highest synergy was observed at a concentration ratio similar to that occurring in the BEO, supporting our initial hypothesis. Taken together, our results deepen the knowledge regarding the effect of BRG and 5-G-7-MOC in SH-SY5Y cells, emphasizing the relevance of their cooperation in achieving this effect.
... Recent studies on the juice from the endocarp of bergamot have shown that it has several bioactivities such as antioxidant, antiinflammatory, neuroprotective, as well as hypolipidemic and hypoglycemic properties (Currò et al., 2016;Miceli et al., 2007;Mollace et al., 2008;Risitano et al., 2014;Trovato et al., 2010;Tundis et al., 2012). Bergamot phytosome is an innovative, food-grade formulation of polyphenols from bergamot (Citrus bergamia Risso et Poiteau, exclusively from plantations in Calabria) standardized to contain 11-19% of total flavonones by HPLC. ...
Bergamot has been traditionally used for the relief of diseases related to oxidative stress. Our aim was to investigate the effect of bergamot phytosome on visceral adipose tissue (VAT) and on metabolic profile, in overweight and obese subjects with mild hypercholesterolemia. A total of 64 participants were randomized into two groups for 12 weeks: a supplemented group (33 individuals, BMI 27 ± 3 kg/m² receiving 500 mg of bergamot phytosome, two daily tablets) and placebo group (31 subjects, BMI 28 ± 3 kg/m², two daily tablets). As to the within differences, the parameters of VAT, total and LDL‐cholesterol were significantly decreased in the bergamot phytosome group, but not in the placebo group. As to between‐group differences, a statistically significant interaction between time and group, that is, the change in score over time differs between the two groups was observed 30 days after supplementation for VAT (p‐value = .005), total cholesterol (p‐value <.0002), and LDL (p = .004) in respect to placebo. The other parameters (glucose, insulin, Homeostasis Model Assessment, high‐density lipoprotein cholesterol, triglycerides, fat free mass, fat mass) were not significant. In conclusion, this clinical study gives evidence that bergamot phytosome provides beneficial effects, such as decrease of VAT and modulation of metabolic alterations, after just 30 days of supplementation, resulting a very promising protection of cardiovascular health.
... Nutraceutical supplementation is considered a viable approach for prophylaxis and treatment of heart diseases [1][2][3][4]. In particular, the efficacy of polyunsaturated fatty acids (PUFAs) in the treatment of various pathologies and, especially, of cardiovascular diseases is known since long time and a large body of clinical data on their protective effect has been collected over the last decades [5][6][7][8], though several pathophysiological implications on their use still remain unclear [9]. ...
Polyunsaturated fatty acids (n-3 PUFAs) are long-chain polyunsaturated fatty acids with 18, 20 or 22 carbon atoms, which have been found able to counteract cardiovascular diseases. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in particular, have been found to produce both vaso-and cardio-protective response via modulation of membrane phospholipids thereby improving cardiac mitochondrial functions and energy production. However, antioxidant properties of n-3 PUFAs, along with their anti-inflammatory effect in both blood vessels and cardiac cells, seem to exert beneficial effects in cardiovascular impairment. In fact, dietary supplementation with n-3 PUFAs has been demonstrated to reduce oxidative stress-related mitochondrial dysfunction and endothelial cell apoptosis, an effect occurring via an increased activity of endogenous antioxidant enzymes. On the other hand, n-3 PUFAs have been shown to counteract the release of pro-inflammatory cytokines in both vascular tissues and in the myocardium, thereby restoring vascular reactivity and myocardial performance. Here we summarize the molecular mechanisms underlying the anti-oxidant and anti-inflammatory effect of n-3 PUFAs in vascular and cardiac tissues and their implication in the prevention and treatment of cardiovascular disease.
... Besides, bergamot juice is rich in 3-hidroxy-3-methylglutaryl neohesperidosides of hesperetin (brutieridine) and naringenin (melitidine) with the ability to inhibit HMG-CoA reductase (Di Donna et al. 2009). These compounds are likely to contribute to the substantial hypolipidemic effects that bergamot juice has demonstrated in several animal studies (Mollace et al. 2008;Miceli et al. 2007). However, to date, there are few human studies that have evaluated the effect of bergamot in adults with dyslipidemia. ...
Dyslipidemia is a well-established modifiable cardiovascular risk. Although statins can reduce LDLc by 50–60%, less than 20% of patients with high risk of CVD achieve LDL targets. The aim of this systematic review is to evaluate the effect of the nutraceutical, bergamot (Citrus bergamia), on lipid parameters in humans. PubMed, Embase, Cochrane Library, and Google Scholar databases were searched for interventional and observational studies investigating the effect of bergamot on lipid profile in humans. This systematic review retrieved a total of 442 studies of which 12 articles fulfilled the eligibility criteria and were included in the qualitative synthesis. Based on data, 75% of studies showed a significant decrease in total cholesterol, triglycerides and LDLc. The decrease in total cholesterol varied from 12.3% to 31.3%, from 7.6% to 40.8% in LDLc and from 11.5% to 39.5% in triglycerides. Eight trials reported HDLc increase after intervention with bergamot. Overall, a dose-dependent and possible synergistic effect when administering with statins can be deducted from these trials. It is essential to point out that studies had heterogeneous designs and scientific quality of studies was quite limited. Promising findings reveal an alternative therapeutic option in dyslipidemia management with bergamot supplementation, especially in subjects with statins intolerance.
... Evidence exists that vascular inflammation is mediated by several mechanisms, which are mainly due to the overexpression of the lectin-like oxidized LDL (LOX-1), a scavenger receptor that selectively internalizes oxLDLs in ECs [61,62]. ...
The maintenance of physiological levels of nitric oxide (NO) produced by eNOS represents a key element for vascular endothelial homeostasis. On the other hand, NO overproduction, due to the activation of iNOS under different stress conditions, leads to endothelial dysfunction and, in the late stages, to the development of atherosclerosis. Oxidized LDLs (oxLDLs) represent the major candidates to trigger biomolecular processes accompanying endothelial dysfunction and vascular inflammation leading to atherosclerosis, though the pathophysiological mechanism still remains to be elucidated. Here, we summarize recent evidence suggesting that oxLDLs produce significant impairment in the modulation of the eNOS/iNOS machinery, downregulating eNOS via the HMGB1-TLR4-Caveolin-1 pathway. On the other hand, increased oxLDLs lead to sustained activation of the scavenger receptor LOX-1 and, subsequently, to NFkB activation, which, in turn, increases iNOS, leading to EC oxidative stress. Finally, these events are associated with reduced protective autophagic response and accelerated apoptotic EC death, which activates atherosclerotic development. Taken together, this information sheds new light on the pathophysiological mechanisms of oxLDL-related impairment of EC functionality and opens new perspectives in atherothrombosis prevention.
... This formation of scar tissue can also result from a balloon angioplasty procedure. An in vivo study evaluated the impact of bergamot on injured blood vessels following angioplasty in rats [20]. Pre-treatment of rats with the nonvolatile fraction of bergamot reduced free radical formation and Lectin-like oxyLDL receptor-1 (LOX-1). ...
The bergamot is a citrus fruit native to southern Italy with traditional uses that include improving immune response and cardiovascular function. There are a variety of phytochemicals that have been found in the bergamot including brutieridin and melitidin as well as other flavonoids, flavones O-glucosides and C-glucosides. Multiple clinical trials have provided evidence that different forms of orally administered bergamot can reduce total cholesterol and low-density lipoprotein cholesterol. In vitro mechanistic studies have provided evidence that polyphenols from the bergamot can alter the function of AMPK and pancreatic cholesterol ester hydrolase (pCEH). The use of bergamot in multiple clinical trials has consistently shown that it is well tolerated in studies ranging from 30 days to 12 weeks. This mini-review reports on the clinical studies performed with different forms of bergamot along with their effectiveness in reducing total cholesterol and LDL cholesterol in patients with hypercholesterolemia.
... Many naturally occurring compounds, including commonly used herbal drugs, were found to have a significant effect on LOX-1. Gingko biloba extract, curcumin, tetramethylpyrazine, ellagic acid and bergamot peet have been shown to decrease LOX-1 expression [50][51][52][53][54]. Other compounds, such as resveratrol, berberine, tanshionone II-A has also shown to decrease atherosclerosis by inhibiting Ox-LDL mediated ROS generation [55]. ...
Oxidized LDL (ox-LDL) plays a central role in atherosclerosis by acting on multiple cells such as endothelial cells, macrophages, platelets, fibroblasts and smooth muscle cells through LOX-1. LOX-1 is a 50 kDa transmembrane glycoprotein that serves as receptor for ox-LDL, modified lipoproteins, activated platelets and advance glycation end-products. Ox-LDL through LOX-1, in endothelial cells, cause increase in leukocyte adhesion molecules, activates pathways of apoptosis, increase reactive oxygen species and cause endothelial dysfunction. In vascular smooth muscle cells and fibroblasts, they stimulate proliferation, migration and collagen synthesis. LOX-1 expressed on macrophages inhibit macrophage migration and stimulate foam cell formation. They also stimulates generation of metalloproteinases and contributes to plaque instability and thrombosis. Drugs that modulates LOX-1 are desirable targets against atherosclerosis. Many naturally occurring compounds have been shown to modulate LOX-1 expression and atherosclerosis. Currently novel drug design techniques are used to identify molecules that can bind to LOX-1 and inhibit its activation by ox-LDL. In addition, techniques using RNA interference and monoclonal antibody against LOX-1 are currently being investigated for clinical use.
... The assay was performed at room temperature. Five microliters of the test compounds (BPF or vehicle), dissolved in ethanol at a concentration 40-fold greater than the final desired test concentration, was added to individual wells in rats, thereby contributing to its hypolipemic and hypoglycemic effect subsequently found in patients on BPF treatment (1)(2)(3). ...
Bergamot polyphenolic fraction (BPF) has been shown to positively modulate several mechanisms involved in metabolic syndrome, suggesting its use in therapy. In particular, it is able to induce a significant amelioration of serum lipid profile in hyperlipemic patients at different levels. The purpose of our study was to investigate the effect of BPF on cholesterol absorption physiologically mediated by pancreatic cholesterol ester hydrolase (pCEH). An in vitro activity assay was performed to study the effect of BPF on pCEH, whereas the rate of cholesterol absorption was evaluated through in vivo studies. In particular, male, Sprague-Dawley rats (200225 g) were fed either normal chow or chow supplemented with 0.5% cholic acid, 5.5% peanut oil, and varying amounts of cholesterol (0 to 1.5%). BPF (10 mg/Kg) was daily administrated by means of a gastric gavage to animals fed with lipid supplemented diet for 4 weeks and, at the end of the study, plasma lipids and liver cholesteryl esters were measured in all experimental groups. Our results show that BPF was able to inhibit pCEH activity and this effect was confirmed, in vivo, via detection of lymphatic cholesteryl ester in rats fed with a cholesterol-rich diet. This evidence clarifies a further mechanism responsible for the hypolipemic properties of BPF previously observed in humans, confirming its beneficial effect in the therapy of hypercholesterolemia and in the treatment of metabolic syndrome.
... The mechanisms of action of bergamot-derived polyphenolic fraction include the reduction of cholesterol absorption and the inhibition of cholesterol biosynthesis, potentiating the effect of rosuvastatin. [138][139][140][141] Muscoli et al 142 recently demonstrated in a rodent model of opioid tolerance that the removal of free radicals with phenolic compounds of olive oil, such as hydroxytyrosol and oleuropein or bergamot polyphenolic fraction derivatives, reinstates the analgesic action of morphine. 143 In particular, evidence exists that removal of nitric oxide, superoxide (SO), and peroxynitrite can prevent and reverse inflammatory pain, neuropathic pain, and morphine-induced hyperalgesia and tolerance. ...
Recently, attention to the lifestyle of patients has been rapidly increasing in the field of pain therapy, particularly with regard to the role of nutrition in pain development and its management. In this review, we summarize the latest findings on the role of nutrition and nutraceuticals, microbiome, obesity, soy, omega-3 fatty acids, and curcumin supplementation as key elements in modulating the efficacy of analgesic treatments, including opioids. These main topics were addressed during the first edition of the Study In Multidisciplinary Pain Research workshop: “FYD (Feed Your Destiny): Fighting Pain”, held on April 7, 2016, in Rome, Italy, which was sponsored by a grant from the Italian Ministry of Instruction on “Nutraceuticals and Innovative Pharmacology”. The take-home message of this workshop was the recognition that patients with chronic pain should undergo nutritional assessment and counseling, which should be initiated at the onset of treatment. Some foods and supplements used in personalized treatment will likely improve clinical outcomes of analgesic therapy and result in considerable improvement of patient compliance and quality of life. From our current perspective, the potential benefit of including nutrition in personalizing pain medicine is formidable and highly promising.
... An active role of naringin (Choe et al., 2001) as well as an inhibition of low-density-lipoproteins (LDL) oxidation of neoeriocitrin and rutin has been proposed (Yu et al., 2005) after studies in animal models of atherosclerosis and diet-induced hypercholesterolemia. Moreover, data obtained from experimental animal models of renal damage and vascular injury have also shown the vasoprotective action of bergamot constituents (Miceli et al., 2007;Mollace et al., 2008;Trovato et al., 2010). ...
Citrus bergamia Risso et Poiteau (“Bergamot”) originated from the Mediterranean ecoregion (southern Italy, Calabria). Bergamot essential oil (BEO) is used in perfumes, cosmetics, and for stress reduction. Juice from C. bergamia has been used for hyperlipidemia. We evaluated literature published on C. bergamia clinical applications. Clinical trials on C. bergamia not combined with other substances, published in English, were searched. We selected ten articles, six describing BEO effects on stress, three reporting effects of polyphenolic fraction of C. bergamia juice in hyperlipidemia and the last describing BEO effects in chronic psoriasis. Clinical studies were analyzed following Consolidated Standards of Reporting Trials for herbal therapy. Studies were conducted on small sample sizes and not have high quality level. Analysis indicates that BEO aromatherapy could be safe and useful to reduce stress symptoms. One study suggests its potential supportive role in ultraviolet B therapy against psoriasis. Supplementation with polyphenols from bergamot juice reduces plasma lipids and improves lipoprotein profile in moderate hyperlipidemia. Effectiveness and safety of C. bergamia cannot be definitively drawn because of publication bias and low quality level of the majority of studies. Further large-scale trials with rigorous design are required to define the role of C. bergamia in clinical practice. Copyright
... with a unique profile of flavonoids and flavonoid glycosides present in its juice and albedo, such as neoeriocitrin, neohesperidin, naringin, rutin, neodesmin, rhoifolin and poncirin (Gliozzi et al. 2014b). While this fruit is primarily used in the fragrance industry for its essential oil extracted from its peel, recent studies on the juice from the endocarp of bergamot have shown that it has several bioactivities such as antioxidant, anti-inflammatory, cytotoxic, neuroprotective as well as hypolipidemic and hypoglycemic properties (Curro et al. 2016;Impellizzeri et al. 2015;Miceli et al. 2007; Mollace et al. 2008;Risitano et al. 2014;Sicari 2016;Trovato et al. 2010;Tundis et al. 2012). From clinical and mechanistic studies, it has been proposed (Mollace et al. 2011) that melitidine and brutieridine in concert with naringin and other flavonone glycosides might be responsible the hypolipidemic effects of BFE and function as do the statin drugs through the direct action on HMG-CoA reductase activity. ...
We examined the clinical safety and efficacy of F105 in 11 subjects with moderate dyslipidemia. F105 is a combination of bergamot fruit extract (Citrus bergamia, BFE) and 9 phytoextracts selected for their ability to improve the antioxidant and anti-inflammatory activity of BFE. In vitro F105 exhibited a synergistic inhibition of oxygen radical absorbing capacity, peroxynitrite formation, and myeloperoxidase activity. Following 12 weeks of F105 daily, no treatment-related adverse events or changes in body mass were seen. Statistically significant changes were noted in total cholesterol (-7.3%), LDL-cholesterol (-10%), non-HDL cholesterol (-7.1%), cholesterol/HDL (-26%), and apolipoprotein B (-2.8%). A post hoc analysis of 8 subjects with HbA1c > 5.4 and HOMA-IR score > 2 or elevated triglycerides revealed additional statistically significant changes in addition to those previously observed in all subjects including triglycerides (-27%), oxLDL (-19%), LDL/HDL (-25%), triglycerides/HDL (-27%), oxLDL/HDL (-25%), and PAI-1 (-37%). A follow-up case report of a 70-year-old female patient, nonresponsive to statin therapy and placed on F105 daily, demonstrated improved cardiometabolic variables over 12 weeks similar to the subgroup. In summary, F105 was clinically well-tolerated and effective for ameliorating dyslipidemia in subjects with moderate cardiometabolic risk factors, particularly in the individuals with HbA1c > 5.4%.
... Furthermore, in a model of carotid arteries injured by balloon angioplasty, balloon injury led to a significant restenosis with smooth muscle cell proliferation and neointima formation, accompanied by increased expression of LOX-1 receptor, malondialdehyde, superoxide formation and nitrotyrosine staining. Pretreatment of rats with BEO-NVF (nonvolatile fraction) reduced the neointima proliferation, LOX-1 expression, MDA overproduction, nitrotyrosine staining and in situ ROS generation in a dose-dependent manner [11]. ...
Citrus Bergamia Risso, commonly known as Bergamot, is a fruit whose Essential Oil and Bergamot Polyphenolic Fraction have numerous medicinal properties. It is also an excellent antioxidant and in this study, for the first time, its potential effect on morphine induced tolerance in mice has been investigated. Our studies revealed that development of antinociceptive tolerance to repeated doses of morphine in mice is consistently associated with increased formation of superoxide, malondialdehyde and tyrosine-nitrated proteins in the dorsal horn of the spinal cord such as the enzyme glutamine synthase. Nitration of this protein is intimately linked to inactivation of its biological function and resulting increase of glutamate levels in the spinal cord. Administration of Bergamot Polyphenolic Fraction (5-50 mg/kg) attenuated tolerance development. This effect was accompanied by reduction of superoxide and malondialdehyde production, prevention of GS nitration, re-establishment of its activity and of glutamate levels. Our studies confirmed the main role of free radicals during the cascade of events induced by prolonged morphine treatment and the co-administration of natural derivatives antioxidant such as Bergamot Polyphenolic Fraction can be an important therapeutic approach to restore opioids analgesic efficacy.
... These flavonoids possess 3hydroxy-3-methylglutaryl moiety with a structural similarity to the natural substrate of HMG-CoA reductase and are likely to exhibit statin-like proprieties [23]. Experimental evidence obtained in animal models of diet induced hypercholesterolemia and renal damage [24,25] as well as in the rat model of mechanical stress-induced vascular injury [26] supports the hypolipemic and vasoprotective effects of bergamot constituents. However, the therapeutic potential of bergamot has never been investigated in human studies, even though the traditional use of BJ in the Calabrian region suggested since long time its potential beneficial use in counteracting atherosclerosis [27]. ...
... For instance, soy and red yeast rice seem to have effects on CV events/mortality (Mannarino et al., 2014;Lu et al., 2008), while some nutraceuticals seem to beneficially affect surrogate markers of vascular damage, such as arterial IMT, endothelial dysfunction and arterial stiffness (Houston et al., 2009). Results obtained in animal models support the hypolipemic and vasoprotective effects of Bergamot constituents such as various bioflavonoids (Choe et al., 2001;Mollace et al., 2008), indicating that Citrus flavonoids might prevent atherosclerosis (Yu et al., 2005;Miceli et al., 2007). FIGURE 4 | Schematic representation of potential lipid lowering effect of Bergavit R (Bergamot-derived flavonoids: 150 mg of flavonoids, with 16% of neoeriocitrin, 47% of neohesperidin and 37% of naringin, daily). ...
Background: Some patients experience statin-induced side effects or prefer nutraceutical approaches for the treatment of dyslipidemia. This has led to a search for alternative therapeutic approaches for dyslipidemia management. In recent studies Citrus bergamia (known as Bergamot) juice was able to reduce serum levels of lipids. Such benefit may be attributed to high amounts of flavonoids contained in Bergamot fruit juice (neoeriocitrin, neohesperidin, naringin). The aim of the present study was to fully investigate the effects of a Bergamot extract on cardio-metabolic parameters, including plasma lipids, atherogenic lipoproteins and subclinical atherosclerosis. Methods: Eighty subjects (42 men and 38 women, mean age: 55±13 years) with moderate hypercholesterolemia (e.g., with plasma LDL-cholesterol concentrations between 160 and 190 mg/dl [between 4.1 and 4.9 mmol/l]) were included. A Bergamot-derived extract (Bergavit®) was given at a fixed dose daily (150 mg of flavonoids, with 16% of neoeriocitrin, 47% of neohesperidin and 37% of naringin) for 6 months. Lipoprotein subfractions were assessed by gel electrophoresis. With this methodology low density lipoprotein (LDL) subclasses are distributed as seven bands (LDL-1 and -2 as large LDL, and LDL-3 to -7 as atherogenic small, dense LDL). Subclinical atherosclerosis was assessed by carotid intima-media thickness (cIMT) using B-mode ultrasound. Results: After 6 months, Bergavit® reduced total cholesterol (from 6.6±0.4 to 5.8±1.1 mmol/l, p
... In this model of stenosis/ atherosclerosis, the balloon injury is induced to the carotid artery in laboratory rats. 30 Bergamot extract (in this case a non-volatile part of bergamot oil) uniformly prevented rapid thickening and inflammatory changes in the arteries subjected to balloon injury. p0145 The final evidence of hypolipemic effects of bergamot polyphenols comes from an extensive placebocontrolled human clinical trial. ...
Bergamot (Citrus bergamia Risso et Poiteau) fruits are characterized by a particularly high content and a unique composition of flavonoids, such as neoeriocitrin, neohesperidin, naringin, melitidin and brutieridin. Bergamot juice and its concentrate, highly enriched in polyphenols-here referred to as Bergamot Polyphenol Fraction (BPF)-has been evaluated in experimental and clinical studies. Studies performed in Italy and Australia showed that BPF treatment leads to an important reduction in lipid parameters in the blood of patients with hyperlipidemia ranging from 15 up to 40% for total cholesterol and cholesterol-LDL. A striking reduction (mean 41.0±2.6%) was also observed for plasma triglyceride levels, accompanied by a significant decrease in blood glucose (22.3±1.0%) in a subgroup of patients with metabolic syndrome. Although BPF cannot be proposed as a substitute for statins in patients at high risk of cardiovascular events, it offers an excellent alternative for low-risk and for statin-intolerant patients. The robust performance of BPF in clinical practice against cardiometabolic risk factors can be explained in the light of scientific evidence showing that bergamot flavonoids influence lipid and sugar metabolism acting as 3-hydroxy-3-methlglutaryl coenzyme A (HMG-CoA) reductase inhibitors and AMP kinase (AMPK) activators.
... Bergamot is an endemic plant of the Calabrian region in southern Italy with a unique profile of flavonoids and flavonoid glycosides present in its juice and albedo, such as neoeriocitrin, neohesperidin, naringin, rutin, neodesmin, rhoifolin, and poncirin (Gliozzi et al. 2014b). While this fruit is primarily used in the fragrance industry for its essential oil extracted from its peel, recent studies on the juice from the endocarp of bergamot have shown that it has several bioactivities such as antioxidant, antiinflammatory, cytotoxic, neuroprotective, as well as hypolipidemic and hypoglycemic properties (Currò et al. 2016;Impellizzeri et al. 2015;Miceli et al. 2007; Mollace et al. 2008;Risitano et al. 2014;Sicari et al. 2016;Trovato et al. 2010;Tundis et al. 2012). From clinical and mechanistic studies, it has been proposed (Mollace et al. 2011) that melitidine and brutieridine in concert with naringin and other flavonone glycosides might be responsible for the hypolipidemic effects of BFE and function as do the statin drugs through the direct action on 3-hydroxy-3-methyl-glutaryl -coenzyme A (HMG-CoA) reductase activity. ...
Oxidative stress plays an important role in the development of many chronic diseases, such as metabolic syndrome and cardiovascular diseases. Antioxidants from foods and dietary supplements help mitigate oxidative stress. The in vitro antioxidant activities of apple fruit, bergamot orange, turmeric root and rhizome, green tea leaf, grape seed, grape skin, olive leaf, blueberry, capsicum and mangosteen pericarp extracts were studied individually and in combinations against reactive oxygen and nitrogen species. F105, a unique mixture of these extracts displayed potent antioxidant synergy in these assays (Figure 1).
... Bergamot essential oil is very appreciated for its organoleptic properties and is be widely used in the manufacture of perfumes. It also exerts biological activities upon the cardiovascular system, [1] possesses antimicrobial activity against a number of common pathogens, [2][3][4] shows neuropharmacological effects [5,6] and in aromatherapy is used to minimize symptoms of stressinduced anxiety and mild mood disorders and cancer pain. [7,8] Bergamot juice (BJ), obtained by squeezing the fruits, is seldom employed by the food industry. ...
Background
Bergamot essential oil (BEO) is obtained from the fruit peel of Citrus bergamia (bergamot), a small tree cultivated almost exclusively along the southern coast of the Calabria region of Italy. BEO is appreciated for its organoleptic properties and is widely used in the manufacture of perfumes. The goals of our study were to investigate the mechanisms underlying the antiproliferative effects of BEO and to identify the compounds mainly responsible for its inhibition of SH-SY5Y cell growth.
Methods
Five BEO extractive fractions (BEOs) differing in chemical composition were used. Cell proliferation was determined by MTT and cell count assays. The trypan blue exclusion test and annexin V/PI staining were done to assess their cytotoxic activity. Genotoxic effects were detected by the comet assay. The cell cycle was also analysed cytofluorimetrically. Reactive oxygen species and Δψm were measured fluorimetrically. Western blotting analyses for some apoptosis-related proteins were carried out.
Findings
Treatment of SH-SY5Y cells with some types of BEOs decreased rate of cell growth by a mechanism correlated to both apoptotic and necrotic cell death. Coloured BEOs act by increasing generation of reactive oxygen species, responsible for the drop in m, and modulating p38 and ERK1/2 MAPKs, p53, Bcl-2 and Bax signalling pathways. Finally, we identified bergamottin and 5-geranyloxy-7-methoxycoumarin as the bioactive molecules that play a pivotal part in the antiproliferative effects exerted by coloured BEOs.
Interpretation
Our study provides novel insights into the antiproliferative effects of BEO, which could be exploited in the context of multitarget pharmacological strategies.
... with a unique profile of flavonoids and flavonoid glycosides present in its juice and albedo, such as neoeriocitrin, neohesperidin, naringin, rutin, neodesmin, rhoifolin and poncirin (Gliozzi et al. 2014b). While this fruit is primarily used in the fragrance industry for its essential oil extracted from its peel, recent studies on the juice from the endocarp of bergamot have shown that it has several bioactivities such as antioxidant, anti-inflammatory, cytotoxic, neuroprotective as well as hypolipidemic and hypoglycemic properties (Curro et al. 2016;Impellizzeri et al. 2015;Miceli et al. 2007; Mollace et al. 2008;Risitano et al. 2014;Sicari 2016;Trovato et al. 2010;Tundis et al. 2012). From clinical and mechanistic studies, it has been proposed (Mollace et al. 2011) that melitidine and brutieridine in concert with naringin and other flavonone glycosides might be responsible the hypolipidemic effects of BFE and function as do the statin drugs through the direct action on HMG-CoA reductase activity. ...
In 2012, it is estimated that 17.5 million people died from cardiovascular disease (CVD) globally.1 Meta-analysis reveals that for every 1% reduction in cholesterol an estimated 2.5% reduction in coronary heart disease;2 in addition emerging science has shown oxLDL to be the most significant predictor of a future cardiac event.3 In a 12-week open-label clinical study of F105, 8 subjects saw the following changes to major cardiovascular risk factors without dietary intervention or weight loss: [1] WHO.int -Cardiovascular Diseases, Fact Sheet No 317.; [2] Holme I. Circulation1990; 82:1916 – 1924.; [3] Johnston, N. et al. Am. J. Cardiol.2006, 97: 640 – 645.
... In the cardiovascular field, it has been shown that the non-volatile fraction of BEO reduced the neointima proliferation in an experimental model of rat angioplasty, inhibiting both free radical production and lectin-like oxyLDL receptor-1 (LOX-1) expression [45]. Moreover, BEO induces vasorelaxation in the mouse aorta by activating K + channels and inhibiting Ca 2+ influx [46]. ...
... Bergamot essential oil is very appreciated for its organoleptic properties and is be widely used in the manufacture of perfumes. It also exerts biological activities upon the cardiovascular system, [1] possesses antimicrobial activity against a number of common pathogens, [2][3][4] shows neuropharmacological effects [5,6] and in aromatherapy is used to minimize symptoms of stressinduced anxiety and mild mood disorders and cancer pain. [7,8] Bergamot juice (BJ), obtained by squeezing the fruits, is seldom employed by the food industry. ...
The goals were to investigate the mechanisms underlying the antiproliferative effects of bergamot essential oil (BEO) and to identify the compounds mainly responsible for its SH-SY5Y cells growth rate inhibition.
Five BEO extractive fractions (BEOs) differing in their chemical composition were used. Cell proliferation was determined by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell count assays. Trypan blue exclusion test and Annexin V/PI staining were performed to assess their cytotoxic activity. Genotoxicity was detected by comet assay. The cell cycle was checked cytofluorimetrically. Reactive oxygen species (ROS) and Δψm were measured fluorimetrically. Western blotting analyses for some apoptosis-related proteins were carried out.
Treatment of SH-SY5Y cells with some types of BEOs decreased cell growth rate by a mechanism correlated to both apoptotic and necrotic cell death. Coloured BEOs act by increasing ROS generation, responsible for the drop in Δψm, and modulate p38 and extracellular signal-regulated kinases (ERK ½) mitogen-activated protein kinases, p53, Bcl-2 and Bax signalling pathways. Finally, we identify bergamottin and 5-geranyloxy-7-methoxycoumarin as the bioactive molecules that could play a pivotal role in the antiproliferative effects exerted by coloured BEOs.
Our study provides novel insights into the field of the antiproliferative effects of BEO, which could be exploited in the context of a multitarget pharmacological strategy.
© 2015 Royal Pharmaceutical Society.
... It is known that lectin-like oxyLDL receptor-1 (LOX-1) is involved in smooth muscle cell proliferation and neo-intima formation occurring in injured blood vessels. Interestingly, in an experimental model of rat angioplasty, pretreatment with the nonvolatile fraction of BEO, reduced the neointima proliferation in a dose-dependent manner, together with free radical formation and LOX-1 expression (Mollace et al., 2008). Moreover, it has been suggested that BEO induces vasorelaxation of the mouse aorta by activating K + channels and inhibiting Ca 2+ influx , which differentially modulates intracellular Ca 2+ levels in vascular endothelial and smooth muscle cells (You et al., 2013). ...
Citrus bergamia Risso et Poiteau, also known as "Bergamot," is a plant belonging to the Rutaceae family, defined as a hybrid of bitter orange and lemon. It is an endemic plant of the Calabria region (Italy). Bergamot fruit is primarily used for the extraction of its essential oil (bergamot essential oil: BEO), employed in perfume, cosmetics, food, and confections. The aim of this review was to collect recent data from the literature on C. bergamia essential oil and, through a critical analysis, focus on safety and the beneficial effects on human health. Clinical studies on the therapeutic applications of BEO exclusively focus on the field of aromatherapy, suggesting that its use can be useful for reducing anxiety and stress.
... The effects of BEO however have been never examined on inflammation and immunity, with the only partial exception of recent circumstantial evidence indicating that in vitro BEO may suppress the COX-2 promoter activity in bovine arterial endothelial cells (Hotta et al., 2010). In vivo, the nonvolatile fraction of BEO has been proven to reduce neointima proliferation, free radical formation, and LOX-1 expression (Mollace et al., 2008). ...
Bergamot (Citrus aurantium L. subsp. bergamia) essential oil (BEO) is used in folk medicine as an antiseptic and anthelminthic and to facilitate wound healing. Evidence indicates that BEO has substantial antimicrobial activity; however its effects on immunity have never been examined. We studied the effects of BEO on reactive oxygen species (ROS) production in human polymorphonuclear leukocytes (PMN) and the role of Ca(2+) in the functional responses evoked by BEO in these cells. Results show that BEO increased intracellular ROS production in human PMN, an effect that required the contribution of extracellular (and, to a lesser extent, of intracellular) Ca(2+) . Bergamot essential oil also significantly increased ROS production induced by the chemotactic peptide N-formyl-Met-Leu-Phe and reduced the response to the protein kinase C activator phorbol myristate acetate. In conclusion, this is the first report showing the ability of BEO to increase ROS production in human PMN. This effect could both contribute to the activity of BEO in infections and in tissue healing as well as underlie an intrinsic proinflammatory potential. The relevance of these findings for the clinical uses of BEO needs careful consideration. Copyright © 2014 John Wiley & Sons, Ltd.
... Recent studies have shown that BEO exerts an anxiolyticlike action in rats subjected to the elevated plus maze test, 4 an antinociceptive effect in a model in which the mouse is exposed to capsaicin, 5 a neuroprotective effect on human SH-SY5Y neuroblastoma cells, 6 a protective effect on human umbilical vein endothelial cells 7 and a protective effect on rat smooth muscle cells. 8 Although limonene is a major compound of BEO, it elicited an increase in renal sympathetic nerve activity and blood pressure. 9 However, administration of linalyl acetate (LA) as a major compound of BEO produced relaxation with rabbit carotid artery, 10 anti-inflammatory, 11 antibacterial 12 and injected into the hindpaw showed a significant reduction of nociceptive response. ...
In the present study, we compared the effect of essential oil of Citrus bergamia Risso (bergamot, BEO) on intracellular Ca levels in vascular endothelial (EA) and mouse vascular smooth muscle (MOVAS) cells, using the fura-2 fluorescence technique. BEO caused an initial transient increase in intracellular Ca concentration ([Ca]i) in EA cells, followed by a decrease, whereas it induced a sustained increase in [Ca]i in MOVAS cells. Linalyl acetate (LA) as a major component of BEO induced-[Ca]i mobilization was similar to BEO in EA cells. The increase of [Ca]i by LA was higher in EA cells than MOVAS cells. [Ca]i rise induced by extracellular Ca application was significantly blocked by BEO or LA in EA cells but not in MOVAS cells, suggesting that BEO and LA block Ca influx in EA cells. The present results suggest that BEO and LA differentially modulate intracellular Ca levels in vascular endothelial and smooth muscle cells. In addition, blockade of Ca influx by BEO and LA in EA cells may explain the protective effects of BEO on endothelial dysfunction associated with cardiovascular disease.
... These flavonoids possess 3-hydroxy-3-methylglutaryl moiety with a structural similarity to the natural substrate of HMG-CoA reductase and are likely to exhibit statin-like proprieties [14]. Experimental evidence obtained in animal models of dietinduced hypercholesterolemia and renal damage [15,16] as well as in the rat model of mechanical stress-induced vascular injury [17] supports the hypolipemic and vasoprotective effects of bergamot constituents. However, the therapeutic potential of bergamot has never been investigated in human studies, even though the traditional use of BJ in the Calabrian region suggested since long time its potential beneficial use in counteracting atherosclerosis. ...
... 3,5 ROS can induce the expression of pro-inflammatory genes and superoxide anions enhance the catabolism of nitric oxide (NO) via the formation of peroxynitrite. 6,7 Antioxidant drugs that reduce ROS/RNS levels have been represented for several years as important therapeutic targets for the treatment of restenosis. 4, 8,9 However, the clinical efficacy of free radical scavengers has been limited due to their short half-life and low penetration in vascular tissues. ...
Reactive oxygen and nitrogen species (e.g., peroxynitrite) may trigger neointima formation leading to restenosis. In a rat carotid endarterectomy (CEA) model, we investigated the effects of the manganese(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP), a superoxide dismutase (SOD) mimetic and peroxynitrite scavenger on neointima formation.
CEA was performed in male Sprague-Dawley rats. Animals received either vehicle (control group; n=15) or 15 mg kg(-1) day(-1) MnTBAP intraperitoneally for 3 weeks (treatment group; n=13). Four groups of carotids were analysed: the left, uninjured carotids (sham) and the right, injured carotids (control CEA) from the control group, the right, injured carotids from the treatment group (CEA+MnTBAP) and an additional group of carotids that were harvested 1h following endarterectomy. The analysis of carotid arteries was performed by histology, immunohistochemistry and real-time polymerase chain reaction (PCR). Plasma malondialdehyde (MDA) levels were measured by lipid hydroperoxidase assay.
Stenosis rate (10.5+/-8.1% vs. 45.4+/-28.3%), the percentage of proliferating cell nuclear antigen-positive cells (13.4+/-7.1% vs. 23.3+/-11.0%) and nitrotyrosine immunoreactivity (5.8+/-1.9 vs. 8.0+/-2.0) were significantly reduced in the vascular wall of the CEA+MnTBAP group compared with control CEA group. Ratio of Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL)-positive nuclei was significantly lower after antioxidant therapy (41.7+/-26.7% vs. 64.9+/-18.5%). Plasma MDA levels increased after endarterectomy (11.7+/-4.8 vs. 4.1+/-2.0 micromol l(-1)) and reduced in the treatment group (3.2+/-2.1 micromol l(-1)). No significant gene regulation after MnTBAP treatment could be noted.
MnTBAP decreased neointima formation, which was associated with reduced vascular smooth muscle cell proliferation and attenuated local and systemic nitro-oxidative stress.
Background:
Metabolic syndrome, also referred to as Syndrome X or obesity syndrome is a cluster of diseases prevalent worldwide in both developed and developing countries. According to WHO, it is referred to as a pathological condition wherein multiple disorders are manifested in the same individual. These include hypertension, hyperglycemia, dyslipidemia and abdominal obesity.
Scope of the problem:
Metabolic syndrome is one of the most serious non-communicable health hazards that have gained pivotal importance in the present scenario. The increasing prevalence affecting around 25 % of the world populace, mainly attributes to the acceptance of western culture, i.e. the intake of high-calorie food along with a substantial decrease in manual labor and adoption of sedentary lifestyles. Therefore, its timely prevention and management are the dire need in the present scenario.
Methods:
For successful accomplishment of the present review, an exhaustive analysis was performed utilizing a pool of previous related literature. The terms used during the search included 'metabolic syndrome, prevalence, etiology, current pharmacotherapy for metabolic syndrome, etc. PUBMED, Medline and SCOPUS were explored for the study of abstracts, research and review papers in the quest for related data. The articles were downloaded and utilized for a meta-analysis study approach.
Conclusion:
In this review, an attempt was made to apprehend and summarize the epidemiology and treatment strategies for metabolic syndrome with a better understanding of its pathogenesis. It was postulated that an early diagnostic approach and subsequent line of treatment is required to prevent the deterioration of an individual's health and life.
This systematic review aimed to evaluate the efficacy of phytochemicals on lipid parameters in patients with hypertriglyceridemia (HTG). A comprehensive search was performed in PubMed/Medline, Scopus, ISI Web of Science, and Google Scholar from inception up to October 2021 to recognize randomized controlled trials (RCTs) assessing the effects of phytochemicals on lipid profiles in patients with HTG. Forty-eight RCTs including 53 arms and comprising 3,478 HTG patients met the eligibility criteria. Phytochemicals significantly reduced the serum levels of triglycerides in 32 out 53 arms, total cholesterol in 22 out of 51, low-density lipoprotein cholesterol in 21 out of 48, very low-density lipoprotein cholesterol in 1 out of 5, apolipoprotein B in 2 out of 4, and lipoprotein(a) levels in 2 out of 4 arms. Furthermore, phytochemicals supplementation increased the levels of high-density lipoprotein cholesterol in 15 out of 48 arms. In brief, phytochemicals supplementation might have beneficial effects on HTG. In most of the studies, phytochemicals had a favorable effect on at least one of the lipid parameters.
Renewed interest in natural products as potential source of drugs led us to investigate on both the anti-inflammatory and anti-nociceptive activity of Citrus bergamia Risso et Poiteau (bergamot) essential oil (BEO). Carrageenan-induced paw edema in rats was used as an experimental model of inflammation. Because of the toxicity of furocoumarins, we performed our study by using the BEO fraction deprived of these compounds (BEO-FF). Treatment with BEO-FF led to a significant inhibition of paw edema induced by a sub-plantar injection of carrageenan. Moreover, histological examination of BEO-FF-treated rat paw biopsies showed a reduction of pathological changes typical of edema. Pre-treatment with BEO-FF significantly reduced interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels in the paw homogenates, as well as nitrite/nitrate and prostaglandin E2 (PGE2) content in exudates. In addition, BEO-FF possesses antioxidant properties, as determined by cell-free assays. Furthermore, results of the writhing test showed that BEO-FF elicited a pronounced analgesic response, as demonstrated by a significant inhibition of constrictions in mice receiving acetic acid, with respect to control animals, whereas the results of the hot plate test suggested that the supra-spinal analgesia participates in the anti-nociceptive effect of BEO-FF. Our study indicates that BEO-FF exerts anti-inflammatory and anti-nociceptive effects, and suggests its potential role as an anti-edemigen and analgesic drug.
Oxidative stress, implying an imbalance between oxidant and anti-oxidant species, is present in the atherosclerotic regions and plays a significant role in the pathogenesis of atherosclerosis and its complications. Recent studies have demonstrated an association between increased oxidative stress and diabetes, hypertension, cigarette smoking and dyslipidemia, which are well known risk factors for atherosclerosis. The endothelial cells, the primary cell line to become dysfunctional early in the course of atherosclerosis internalizes ox-LDL mainly through its receptor LOX-1 which is responsible for many of the downstream effects on smooth muscle cell ans monocyte biology. Inhibition of LOX-1 by gene deletion significantly reduces atherogenesis in animal models. Many of the currently used drugs modulate atherosclerosis by their action on LOX-1 receptor. New molecules that modulate LOX-1 are currently under investigation. sLOX-1 is a potential biomarker in acute coronary injury and further studies needs to be done before it can be put to clinical use.
Objective:
Hyperlipemia represents an independent risk factor in the development of atherosclerosis in patients undergoing type 2 diabetes mellitus (DM). Moreover, the pharmacological treatment of dyslipemia in patients undergoing type 2 DM (e.g. by means of statins), is accompanied by relevant side effects and oral supplementation with natural antioxidants, such as Citrus polyphenols, has recently been suggested to improve cardioprotection in such patients. However, due to the poor gastrointestinal absorption of polyphenols, novel formulations have recently been developed for getting a better bioavailability of polyphenolic rich fractions of citrus species extract rich in polyphenols.
Methods:
Here, we investigated the effect of standard bergamot polyphenolic fraction (BPF®) as well as of its phytosomal formulation (BPF Phyto), in patients with type 2 DM and hyperlipemia. A randomized, double blind, placebo-controlled study was carried out in 60 patients suffering from type 2 DM and mixed hyperlipemia. Patients were divided into three groups: one receiving placebo, the second receiving standard BPF and the third BPF Phyto.
Results:
In the groups receiving BPF and BPF Phyto, a significant reduction of fasting plasma glucose, serum LDL cholesterol and triglycerides accompanied by increased HDL cholesterol was observed. This effect was associated with significant reduction of small dense atherogenic LDL particles, as detected by means of proton NMR Spectroscopy, thus confirming the hypolipemic and hypoglycemic effect of bergamot extract both when using standard formulation as well as BPF Phyto. No differences were seen in the therapeutic response among groups receiving BPF and BPF Phyto, thus suggesting a substantial bioequivalence in their hypoglycemic and hypolipemic profile. However, when comparing the pharmacokinetic profile of naringin (the major component of BPF) and its metabolites, in patients treated with BPF Phyto, an at least 2,5 fold increase in its absorption was found, confirming in human studies the better profile of BPF Phyto compared to standard BPF.
Conclusion:
These data suggest that better absorption and tissue distribution of BPF Phyto formulation represents an innovative approach in supplementation treatments of cardiometabolic disorders.
Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), one of the scavenger receptors for oxidized low-density lipoprotein cholesterol (ox-LDL), plays a crucial role in the uptake of ox-LDL by cells in the arterial wall. Mounting evidence suggests a role for LOX-1 in various steps of the atherosclerotic process, from initiation to plaque destabilization. Studies of the genetic structure of LOX-1 have also uncovered various genetic polymorphisms that could modulate the risk of atherosclerotic cardiovascular events. As evidence supporting the vital role of LOX-1 in atherogenesis keeps accumulating, there is growing interest in LOX-1 as a potential therapeutic target. This review discusses the discovery and genetics of LOX-1; describes existing evidence supporting the role of LOX-1 in atherogenesis and its major complication, myocardial ischemia; and summarizes LOX-1 modulation by some naturally occurring compounds and efforts toward development of small molecules and biologics that could be of therapeutic use.
Background:
Statins are the most common used lipid lowering drugs but they may cause adverse effects and despite their well-established therapeutic benefits residual cardiovascular (CV) risk remains. The use of other lipid lowering drugs and nutraceuticals alone or as add-on lipid-modifying therapy can be an option in such cases. Several studies have reported health-related properties of the Citrus fruits, among which bergamot (Citrus bergamia Risso) differs from others by particularly high content of certain compounds.
Purpose:
This narrative review summarizes the current evidence on the effects of bergamot on lipid parameters based on studies involving animals and humans.
Main evidence:
This natural supplement may lead to effective lipid-lowering treatment. Its lipid-lowering activity is attributed to different flavonoids. However, the exact mechanisms involved remain unclear.
Conclusion:
It is expected that ongoing and future studies will confirm the benefit of bergamot in dyslipidemic and other cardiometabolic disorders, potentially leading to reduced overall CV risk.
Doxorubicin (DOXO) is one of the most widely used and successful antineoplastic drugs in treating hematologic cancers and malignant neoplasms in both adults and children, however, its clinical use is seriously limited due to the development of acute and chronic cardiotoxicity leading to cardiomyopathy and congestive heart failure throughout life.
Although the molecular pathogenesis of anthracycline cardiotoxicity remains to be clarified several investigations have proved that intramyocardial production of reactive oxygen species has been the primary cause of DOXO-induced cardiotoxicity. This oxidative stress-based hypothesis sheds light on the development of protective strategies using natural antioxidants without altering therapeutic effectiveness of DOXO. Bioactive plant constituents of dietary supplements with potential beneficial implications in human health can play an important role against DOXO-induced cardiac side effects. In this regard, dietary polyphenols, in particular flavonoids, are abundant micronutrients in our diet and emerging evidence suggest a potential protective role in the prevention of degenerative diseases such as cardiovascular diseases due to their pleiotropic anti-oxidative and anti-inflammatory effects. In this review we summarizes what is known about the basic molecular mechanisms by which DOXO induced oxidative stress and findings of studies undertaken to identify the cardioprotective properties of polyphenols during DOXO chemotherapy.
Cited By (since 1996):1, Export Date: 23 March 2014, Source: Scopus
Statins are the most commonly prescribed drugs to reduce cardiometabolic risk. Besides the well-known efficacy of such compounds in both preventing and treating cardiometabolic disorders, some patients experience statin-induced side effects. We hypothesize that the use of natural bergamot-derived polyphenols may allow patients undergoing statin treatment to reduce effective doses while achieving target lipid values. The aim of the present study is to investigate the occurrence of an enhanced effect of bergamot-derived polyphenolic fraction (BPF) on rosuvastatin-induced hypolipidemic and vasoprotective response in patients with mixed hyperlipidemia.
A prospective, open-label, parallel group, placebo-controlled study on 77 patients with elevated serum LDL-C and triglycerides was designed. Patients were randomly assigned to a control group receiving placebo (n=15), two groups receiving orally administered rosuvastatin (10 and 20mg/daily for 30days; n=16 for each group), a group receiving BPF alone orally (1000mg/daily for 30days; n=15) and a group receiving BPF (1000mg/daily given orally) plus rosuvastatin (10mg/daily for 30days; n=15).
Both doses of rosuvastatin and BPF reduced total cholesterol, LDL-C, the LDL-C/HDL-C ratio and urinary mevalonate in hyperlipidemic patients, compared to control group. The cholesterol lowering effect was accompanied by reductions of malondialdehyde, oxyLDL receptor LOX-1 and phosphoPKB, which are all biomarkers of oxidative vascular damage, in peripheral polymorphonuclear cells.
Addition of BPF to rosuvastatin significantly enhanced rosuvastatin-induced effect on serum lipemic profile compared to rosuvastatin alone. This lipid-lowering effect was associated with significant reductions of biomarkers used for detecting oxidative vascular damage, suggesting a multi-action enhanced potential for BPF in patients on statin therapy.
The aim of this study was to explore the effect of the essential oil of Citrus bergamia Risso (bergamot) on mouse blood vessels and to analyse the mechanism of this effect from a pharmacological perspective.
We investigated the effect of bergamot essential oil (BEO) on vascular tonus during contraction of mouse aorta induced by prostaglandin F2α (PGF2α ) or noradrenaline (norepinephrine).
In mouse aortic rings, BEO (0.01, 0.1 and 0.2% v/v) reduced contraction in a dose-dependent manner, and relaxed the vascular tonus induced by PGF2α . No significant difference in the extent of vasorelaxation induced by 0.1% (v/v) BEO was evident when rings with intact endothelium and endothelium-denuded rings were compared. When aortic rings were suspended in a medium that was Ca(2+) -free but contained 80 mm KCl, addition of CaCl2 (1, 2.5 or 5 mm) induced contraction in a dose-dependent manner. However, addition of Ca(2+) after incubation of the rings with BEO strongly suppressed CaCl2 -induced contraction. Further, the K(+) -channel blocker tetraethylammonium chloride partially blocked BEO-induced vasorelaxation.
Our findings suggest that BEO may induce endothelium-independent vasorelaxation by regulating the vascular tone of smooth muscle. Activation of K(+) channels and inhibition of Ca(2+) influx may be involved in vasorelaxation of mouse aorta elicited by BEO.
Bergamot oil (Citrus bergamia) is mainly employed in the perfumery and cosmetic industries and also, in a smaller amount, in the pharmaceutical and food industries, for its fragrant notes, fixative and antimicrobial properties. Due to the presence of some phototoxic compounds in its composition, it has become a common practice to reduce or sometimes completely eliminate these substances before using the oil. Samples of treated bergamot oils have been investigated in this study (terpeneless, furocoumarin- and bergapten-free) by means of GC–FID, GC–MS, enantio-GC–FID and HPLC. The results are reported in terms of either peak areas or g/100 g. Some considerations are made in order to discuss the technologies used for treating bergamot oil. Copyright © 2009 John Wiley & Sons, Ltd.
Lectin-like oxidized LDL receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL (oxLDL) and plays multiple roles in the development of cardiovascular diseases. We screened more than 400 foodstuff extracts for identifying materials that inhibit oxLDL binding to LOX-1. Results showed that 52 extracts inhibited LOX-1 by more than 70% in cell-free assays. Subsequent cell-based assays revealed that a variety of foodstuffs known to be rich in procyanidins such as grape seed extracts and apple polyphenols, potently inhibited oxLDL uptake in Chinese hamster ovary (CHO) cells expressing LOX-1. Indeed, purified procyanidins significantly inhibited oxLDL binding to LOX-1 while other ingredients of apple polyphenols did not. Moreover, chronic administration of oligomeric procyanidins suppressed lipid accumulation in vascular wall in hypertensive rats fed with high fat diet. These results suggest that procyanidins are LOX-1 inhibitors and LOX-1 inhibition might be a possible underlying mechanism of the well-known vascular protective effects of red wine, the French Paradox.
(Communicated by Masanori OTSUKA, M.J.A.)
We tested whether serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) levels are able to predict in-stent restenosis (ISR) after successful primary percutaneous coronary intervention (PCI).
Preprocedural and postprocedural serum sLOX-1 levels were measured in 210 consecutive patients with stable coronary artery disease who underwent successful primary PCI for de novo lesions. The patients were grouped as ISR and non-ISR based on angiographic follow-up results.
PCI significantly increased serum sLOX-1 levels both in patients with [0.85 (range: 0.63-0.98) vs. 0.39 (range: 0.27-0.54) ng/ml, P < 0.01] or without ISR [0.45 (range: 0.36-0.84) vs. 0.32 (range: 0.28-0.62) ng/ml, P < 0.01]. Postprocedural serum sLOX-1 levels were higher in patients with ISR than those without ISR [0.85 (range: 0.63-0.98) vs. 0.45 (range: 0.36-0.84) ng/ml, P < 0.01]. High postprocedural serum sLOX-1 levels served as independent predictors of ISR (odds ratio: 3.040, 95% confidence interval: 1.359-6.802, P < 0.01). Furthermore, postprocedural serum sLOX-1 levels were correlated with late lumen loss of the stented lesions (ρ = 0.36, P < 0.01).
Postprocedural serum sLOX-1 levels are significantly associated with the risk of ISR and the severity of lumen loss in patients with stable coronary artery disease undergoing primary PCI. These results suggested that postprocedural serum sLOX-1 levels might be useful for the detection and risk assessment of ISR after PCI.
Bergamot ( Citrus bergamia Risso) is a less commercialized Citrus fruit, mainly used for its essential oil extracted from the peel. Bergamot peel (BP) represents about 60% of the processed fruits and is regarded as primary waste. However, it contains good amounts of useful compounds, such as pectins and flavonoids. Many of the bioactivities of Citrus flavonoids appear to impact vascular endothelial cells. Herein, we report the protective effect of two flavonoid-rich extracts from BP (endowed with radical-scavenging properties and lacking genotoxic activity) against alterations in cell modifications induced by the pleiotropic inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) on human umbilical vein endothelial cells (HUVECs), as demonstrated by monitoring intracellular levels of malondialdehyde/4-hydroxynonenal, reduced and oxidized glutathione and superoxide dismutase activity, and the activation status of nuclear factor-kappaB (NF-kappaB). Thus, BP appears to be a potential source of natural antioxidant/anti-inflammatory phytocomplexes to be employed as ingredients of nutraceutical products or functional foods.
After exposure to low density lipoprotein (LDL) that had been minimally modified by oxidation (MM-LDL), human endothelial cells (EC) and smooth muscle cells (SMC) cultured separately or together produced 2- to 3-fold more monocyte chemotactic activity than did control cells or cells exposed to freshly isolated LDL. This increase in monocyte chemotactic activity was paralleled by increases in mRNA levels for a monocyte chemotactic protein 1 (MCP-1) that is constitutively produced by the human glioma U-105MG cell line. Antibody that had been prepared against cultured baboon smooth muscle cell chemotactic factor (anti-SMCF) did not inhibit monocyte migration induced by the potent bacterial chemotactic factor f-Met-Leu-Phe. However, anti-SMCF completely inhibited the monocyte chemotactic activity found in the media of U-105MG cells, EC, and SMC before and after exposure to MM-LDL. Moreover, monocyte migration into the subendothelial space of a coculture of EC and SMC that had been exposed to MM-LDL was completely inhibited by anti-SMCF. Anti-SMCF specifically immunoprecipitated 10-kDa and 12.5-kDa proteins from EC. Incorporation of [35S]methionine into the immunoprecipitated proteins paralleled the monocyte chemotactic activity found in the medium of MM-LDL stimulated EC and the levels of MCP-1 mRNA found in the EC. We conclude that (i) SMCF is in fact MCP-1 and (ii) MCP-1 is induced by MM-LDL.
A variable degree of smooth muscle cell (SMC) proliferation after balloon injury has been reported in previous rat studies. It is unknown whether balloon injury induces c-fos expression and whether it is related to the degree of vascular injury in vivo. Therefore, we tested the hypothesis that proportional increases in neointimal formation and c-fos expression might be present after different degrees of balloon dilation.
Angioplasty of the carotid artery was performed with a balloon catheter. Vascular injury was evaluated at 0, 0.5, 1.0, 1.5, and 2 atm (n = 6 for all). In 40 additional rats, total RNA dot blots were performed to assess the effect of various degrees of balloon injury on c-fos expression. SMC proliferation proportional to the increases of inflation pressure was found between 0 and 2 atm with neointimal areas of 0.002 +/- 0.002, 0.069 +/- 0.014, 0.128 +/- 0.043, 0.190 +/- 0.010, and 0.255 +/- 0.041 mm2, respectively. When the degree of SMC proliferation (neointima and neointima/media ratio) was plotted against balloon inflation pressure, a linear relation was observed (r = .733, P < .001 and r = .755, P < .001, respectively). An increase in c-fos expression proportional to the degree of injury was found 30 minutes after injury.
Neointimal proliferation produced by balloon injury is related to balloon inflation pressure, supporting the concept of an SMC proliferative response proportional to the degree of injury. The increase in SMC proliferation is associated with a proportional increase in the early expression of the c-fos nuclear proto-oncogene.
This study sought to characterize leukocyte and platelet activation and adhesion molecule expression after coronary angioplasty.
Coronary angioplasty can be regarded as a clinical model of postischemic inflammation because this intervention leads to the release of inflammatory mediators as a result of plaque rupture and endothelial injury.
In 13 patients with stable angina (mean [ +/- SEM] age 56.0 +/- 2.4 years, range 44 to 79), blood samples were drawn from the aorta and coronary sinus immediately before and immediately and 15 min after coronary angioplasty. Subsequently, leukocyte and platelet functions were determined. Eleven control patients (57.5 +/- 2.3 years, range 52 to 78) underwent coronary arteriography.
Coronary arteriography and angioplasty showed no difference in number of leukocytes between the coronary sinus and the aorta. However, 15 min after coronary angioplasty, there was an increase in neutrophil CD18 and CD11b, monocyte CD14 and platelet glycoprotein IIb/IIIa expression and a decrease in neutrophil L-selectin expression (189 +/- 25%, 163 +/- 27%, 158 +/- 35%, 141 +/- 22% and 31 +/- 10%, respectively, p < 0.01). In the control subjects, no change in adhesion molecule expression occurred. Superoxide production and aggregation in ex vivo-stimulated neutrophils collected from the coronary sinus 15 min after coronary angioplasty was significantly decreased compared with that after coronary arteriography (54 +/- 12% vs. 106 +/- 30% and 58 +/- 11% vs. 102 +/- 29%, respectively, p < 0.01). The reduced responses to phorbol ester stimulation may be explained by previous in vivo activation of neutrophils during coronary angioplasty.
Coronary angioplasty increases neutrophil, monocyte and platelet adhesion molecule expression and induces a significant decrease in ex vivo-stimulated neutrophil superoxide generation and aggregation. These findings suggest that coronary angioplasty triggers cellular activation with an inflammatory response that could contribute to restenosis.
Lectin-like oxidized low-density lipoprotein receptor (LOX-1) is a recently identified receptor for oxidized low-density lipoprotein, one of the major atherogenic substances. Although LOX-1 was reported to be expressed abundantly in endothelial cells, including atheromatous lesions, the regulation of LOX-1 gene has not yet been clarified. In the present study, we isolated the rat LOX-1 gene and investigated the regulation of gene expression. The rat LOX-1 gene was encoded by a single copy gene spanning over 19 kilobases and consisted of eight exons. Exon boundaries correlated well with the functional domain boundaries of the receptor protein. The promoter region contained putative TATA and CAAT boxes and multiple cis-elements such as NF-kappaB, AP-1 and AP-2 sites, and a shear stress response element. Northern blot analysis revealed that LOX-1 gene expression was up-regulated 9-fold by shear stress, 21-fold by lipopolysaccharide, and 4-fold by tumor necrosis factor-alpha, in cultured vascular endothelial cells. LOX-1 was also expressed in macrophages but not in vascular smooth muscle cells. These data provide important information for elucidating the molecular mechanisms of LOX-1 gene regulation and suggest a role for LOX-1 in the pathophysiology of atherosclerotic cardiovascular disease.
Angioplasty is a principal treatment for occlusive vascular disease but 30-50% of patients show a restenosis of the vessel. There is no clinical effective therapy for this disease. It has been demonstrated, in animal models, that various drugs such as NO-donor, plasminogen inhibitor tranexamic acid and MMP (matrix metalloproteinases) reduce the rate of restenosis. Other therapeutic approaches are cytotoxic therapy, and strategies to inhibit cell cycle progression. Systemic administration of conventional pharmacologic agents inhibit cell cycle kinases and vascular lesion formation in animal models. As cell cycle progression is accompanied by fluctuations in the concentration of adenosine 3',5-monophospate (cAMP) and in the activity of the cAMP dependent protein kinase (PKA), local administration of cAMP and phospodiesterase-inhibitor drugs (aminophylline or amrinone) markedly inhibit neointima formation. The successful use of local radiation therapy to inhibit neointima formation after vascular injury may reflect a similar combination of cell-cycle arrest and vascular cell apoptosis. The most effective therapy for occlusive vascular disease will likely combine intravascular stenting with an antiproliferative therapy.
The effects of bergamot essential oil (BEO; Citrus bergamia, Risso) on excitotoxic neuronal damage was investigated in vitro.
The study was performed in human SH-SY5Y neuroblastoma cells exposed to N-methyl-D-aspartate (NMDA). Cell viability was measured by dye exclusion. Reactive oxygen species (ROS) and caspase-3 activity were measured fluorimetrically. Calpain I activity and the activation (phosphorylation) of Akt and glycogen synthase kinase-3beta (GSK-3beta) were assayed by Western blotting.
NMDA induced concentration-dependent, receptor-mediated, death of SH-SY5Y cells, ranging from 11 to 25% (0.25-5 mM). Cell death induced by 1 mM NMDA (21%) was preceded by a significant accumulation of intracellular ROS and by a rapid activation of the calcium-activated protease calpain I. In addition, NMDA caused a rapid deactivation of Akt kinase and this preceded the detrimental activation of the downstream kinase, GSK-3beta. BEO (0.0005-0.01%) concentration dependently reduced death of SH-SY5Y cells caused by 1 mM NMDA. In addition to preventing ROS accumulation and activation of calpain, BEO (0.01%) counteracted the deactivation of Akt and the consequent activation of GSK-3beta, induced by NMDA. Results obtained by using specific fractions of BEO, suggested that monoterpene hydrocarbons were responsible for neuroprotection afforded by BEO against NMDA-induced cell death.
Our data demonstrate that BEO reduces neuronal damage caused in vitro by excitotoxic stimuli and that this neuroprotection was associated with prevention of injury-induced engagement of critical death pathways.
BACKGROUND. Acute closure remains a significant limitation of percutaneous transluminal coronary angioplasty (PTCA) and underlies the majority of ischemic complications. This study details the clinical and angiographic characteristics of a series of patients receiving an intracoronary stent device to manage acute and threatened closure and presents the early clinical results. METHODS AND RESULTS. From October 1989 through June 1991, 115 patients undergoing PTCA received intracoronary stents to treat acute or threatened closure in 119 vessels. Sixty-three percent had multivessel coronary disease, 33 (29%) had undergone prior coronary artery bypass grafting (CABG), and 52 (45%) had had previous PTCA. Using the American College of Cardiology/American Heart Association (ACC/AHA) classification, 15% of lesions were class A, 55% were class B, and 30% were class C. Eight patients were referred with severe coronary dissection and unstable angina after PTCA at other institutions. Acute closure was defined as occlusion of the vessel with TIMI (Thrombolysis in Myocardial Infarction) 0 or 1 flow immediately before stent placement. Threatened closure required two or more of the following criteria: 1) a residual stenosis greater than 50%, 2) TIMI grade 2 flow, 3) angiographic dissection comprising extraluminal dye extravasation and/or a length of greater than 15 mm, 4) evidence of clinical ischemia (either typical angina or ECG changes). Twelve vessels (10%) met the criteria for acute closure, and 87 vessels (73%) satisfied the criteria for threatened closure. Twenty vessels (17%) failed to meet two criteria. Stenting produced optimal angiographic results in 111 vessels (93%), with mean diameter stenosis (+/- 1 SD) reduced from 83 +/- 12% before to 18 +/- 29% after stenting. Overall, in-hospital mortality was 1.7% and CABG was required in 4.2%; Q wave myocardial infarction (MI) occurred in 7% and non-Q wave MI in 9%. Stent thrombosis occurred in nine patients (7.6%). For the 108 patients who presented to the catheterization laboratory without evolving MI, Q wave MI occurred in 4% and non-Q wave MI occurred in 7%. Angiographic follow-up has been performed in 81 eligible patients (76%), and 34 patients (41%) had a lesion of greater than or equal to 50%. CONCLUSIONS. This stent may be a useful adjunct to balloon dilatation in acute or threatened closure. Randomized studies comparing this stent with alternative technologies are required.
To determine risk factors for restenosis, we studied 998 patients who underwent elective coronary angioplasty (PTCA) to native coronary arteries between July 1980 and July 1984. Restenosis, defined as a luminal narrowing of greater than 50% at follow-up, was present in 302 patients (30.2%). Univariate analysis of 29 factors revealed seven factors related to restenosis: vessel dilated (circumflex coronary artery 18%, right coronary artery 27%, left anterior descending artery 34%; p less than .01), final gradient of 15 mm Hg or less compared with greater than 15 mm Hg (27% vs 38%, p less than .01), duration of angina greater than 2 months compared with angina of shorter duration (27% vs 35%, p = .01), post-PTCA stenosis of 30% or less compared with 31% to 50% (28% vs 36%, p less than .025), stable vs unstable angina (26% vs 34%, p less than .05), presence vs absence of intimal dissection (26% vs 32%, p = .07), and female gender vs male gender (25% vs 32%, p = .08). Multivariate analysis revealed five factors independently related to increased risk of restenosis in the following order of importance: PTCA in the left anterior descending artery, absence of intimal dissection immediately after PTCA, final gradient greater than 15 mm Hg, a large residual stenosis after PTCA, and unstable angina. Restenosis after PTCA is a multifactorial problem. The hemodynamic and angiographic result at the time of PTCA significantly influences long-term outcome, but additional measures aimed at reducing the rate of recurrence of atherosclerotic plaque are required.
Repeat coronary angiography was performed within 6 months after successful percutaneous transluminal coronary angioplasty (PTCA) in 178 of our first 181 patients (98%). The remaining 3 patients were symptom free, had negative treadmill exercise test results and were considered not to have had restenosis. A second follow-up angiogram was performed in 107 patients (59%), including all patients with persistent or recurrent anginal symptoms, between 7 and 18 months after PTCA. Fifty-one of the 181 patients (28%) had restenosis on 51 of 205 successfully dilated segments (25%). The stenosis was greater than or equal to 70% in 49 of these 51 segments; it was 65% and 55%, respectively, in the 2 remaining patients. Restenosis was documented angiographically at a median time of 4.7 +/- 4 months. However, 47 patients (92%) had restenosis documented within 6 months, 2 between 7 and 12 months and 2 between 13 and 18 months after PTCA. Stepwise logistic regression analysis selected the following factors as independent predictors of restenosis after PTCA: variant angina, multivessel disease, severity of residual stenosis and less reduction in the diameter of the stenosis on the angiogram immediately after PTCA. Of these 4 factors, the degree of residual stenosis immediately after PTCA was by far the most significant. It is concluded that restenosis occurs in approximately 25% of patients, almost always within the first 6 months, after successful PTCA. The degree of residual stenosis after PTCA is the most important predictor of restenosis. Increased experience and improved instrumentation may eventually lead to less residual stenosis and better late results after PTCA.
OVER the past decade, percutaneous transluminal coronary angioplasty has gained wide acceptance as the procedure of choice in many patients with atherosclerotic coronary artery disease. As experience with the procedure has grown, its rate of success has risen to approximately 90 percent and the incidence of acute complications has fallen; as a result, emergency coronary-artery bypass surgery is required in less than 4 percent of patients.1 2 3 Despite these improvements, re-Stenosis in the days, weeks, or months after successful angioplasty of a narrowed coronary artery occurs in 25 to 35 percent of patients,3 4 5 6 7 or 45 to 55 percent of those with . . .
The results of follow-up angiography in patients from 27 clinical centers enrolled in the PTCA Registry were analyzed to evaluate restenosis after PTCA. Of 665 patients with successful PTCA, 557 (84%) had follow-up angiography (median follow-up 188 days). Restenosis, defined as an increase of at least 30% from the immediate post-PTCA stenosis to the follow-up stenosis or a loss of at least 50% of the gain achieved at PTCA, was seen in 187 patients (33.6%). The incidence of restenosis in patients who underwent follow-up angiography was highest within the first 5 months after PTCA. Restenosis was found in 56% of patients with definite or probable angina after PTCA and in 14% of patients without angina after PTCA. Twenty-four percent of patients with restenosis did not have either definite or probable angina. Multivariate analysis selected 4 factors associated with increased rate of restenosis: male sex, PTCA of bypass graft stenosis, severity of angina before PTCA and no history of MI before PTCA.
Most strategies designed to reduce restenosis by the use of pharmacological or biological reagents involve direct inhibition of vascular smooth muscle cell (SMC) proliferation. Alternatively, SMC proliferation might be indirectly inhibited if reendothelialization could be specifically facilitated at sites of balloon-induced arterial injury. Accordingly, we investigated the hypothesis that application of an endothelial cell (EC)-specific mitogen to a freshly denuded intimal surface could accelerate reendothelialization and thereby attenuate intimal hyperplasia.
The left carotid artery of 31 Sprague-Dawley rats was subjected to balloon injury, after which 16 rats were treated with a 30-minute incubation with 100 micrograms of vascular endothelial growth factor (VEGF), an EC-specific mitogen. Control animals (n = 15) received a 30-minute incubation with 0.9% saline. At 2 weeks after balloon injury, carotid artery reendothelialization was markedly superior in the VEGF-treated group compared with the control group (14.59 +/- 1.12 versus 7.96 +/- 0.51 mm2, P < 0.005). The extent of reendothelialization measured at 4 weeks after balloon injury remained superior for arteries treated with VEGF (18.04 +/- 0.90 mm2) versus saline (13.42 +/- 0.84 mm2, P < .005). Neointimal thickening was correspondingly attenuated to a statistically significant degree in arteries treated with VEGF versus the control group at both the 2-week and 4-week time points. Immunostaining for proliferating cell nuclear antigen (PCNA) disclosed a threefold increase in PCNA-positive cells in the neointima of control arteries versus VEGF-treated arteries at 2 weeks after injury.
Application of VEGF, an EC-specific growth regulatory molecule, may be effectively used in vivo to promote reendothelialization and thereby indirectly attenuate neointimal thickening due to SMC proliferation.
This study was performed to define the evolution of lesion morphology and its relation to thrombus formation and smooth muscle cell proliferation after experimental coronary stent placement.
Restenosis after percutaneous revascularization may develop because of thrombus accumulation and smooth muscle cell proliferation. In animal models of restenosis, thrombus may assume a significant role in neointimal formation by providing an absorbable matrix into which smooth muscle cells proliferate.
Twenty-eight oversized stents were placed in the coronary arteries of 23 juvenile domestic pigs. The histologic degree of vessel injury, lesion morphometry and smooth muscle cell proliferation measured by immunolocalization with a monoclonal antibody to proliferating cell nuclear antigen (PCNA) were assessed at 24 h and 7, 14 and 28 days after stent placement.
The area of thrombus was minimal at 24 h ([mean +/- SE] 0.44 +/- 0.12 mm2). Neointimal area at 7 days (0.72 +/- 0.20 mm2) was similar to the area of thrombus, followed by a significant increase at 14 days (3.15 +/- 0.39 mm2) and 28 days (3.30 +/- 0.28 mm2) (p < 0.0036, 24 h and 7 days vs. 14 and 28 days). At 14 and 28 days, neointimal thickness correlated with the histologic degree of vessel injury (p < 0.003). In arteries with severe injury, the increase in neointimal thickness is accounted for by replacement of the damaged media. The smooth muscle cell proliferation index was 18.6 +/- 3.5% at 7 days compared with 9.6 +/- 1.3% by 14 days (p = 0.0247) and declined to 1.1 +/- 0.97% by 28 days (p < 0.008, 7 and 14 days vs. 28 days).
Early thrombus formation is minimal, and thrombus accounts for a small portion of subsequent neointimal formation. Smooth muscle cell proliferation and matrix formation are the major factors relating to neointimal formation in this proliferative model of restenosis. The evolution of neointimal formation after coronary stenting shows maximal smooth muscle cell proliferation at 7 days, with a decline to low levels by 28 days. Therefore, these data may be useful for developing effective therapies for restenosis.
Studies have suggested that restenosis within Palmaz-Schatz stents results from neointimal hyperplasia or chronic stent recoil and occurs more frequently at the articulation.
Serial intravascular ultrasound (IVUS) was performed after intervention and at follow-up in 142 stents in 115 lesions. IVUS measurements (external elastic membrane [EEM], stent, and lumen cross-sectional areas [CSAs] and diameters) were performed, and plaque CSA (EEM lumen in reference segments and stent lumen in stented segments), late lumen loss (delta lumen), remodeling (delta EEM in reference segments and delta stent in stented segments), and tissue growth (delta plaque) were calculated. After intervention, the lumen tended to be smallest at the articulation because of tissue prolapse. At follow-up, tissue growth was uniformly distributed throughout the stent; the tendency for greater neointimal tissue accumulation at the central articulation reached statistical significance only when normalized for the smaller postintervention lumen CSA. In stented segments, late lumen area loss correlated strongly with tissue growth but only weakly with remodeling. Stents affected adjacent vessel segments; remodeling progressively increased and tissue growth progressively decreased at distances from the edge of the stent. These findings were similar in native arteries and saphenous vein grafts and in lesions treated with one or two stents. There was no difference in the postintervention or follow-up lumen (at the junction of the two stents) when overlapped were compared with nonoverlapped stents.
Late lumen loss and in-stent restenosis were the result of neointimal tissue proliferation, which tended to be uniformly distributed over the length of the stent.
Endothelial dysfunction or activation elicited by oxidatively modified low-density lipoprotein (Ox-LDL) has been implicated in the pathogenesis of atherosclerosis, characterized by intimal thickening and lipid deposition in the arteries. Ox-LDL and its lipid constituents impair endothelial production of nitric oxide, and induce the endothelial expression of leukocyte adhesion molecules and smooth-muscle growth factors, which may be involved in atherogenesis. Vascular endothelial cells in culture and in vivo internalize and degrade Ox-LDL through a putative receptor-mediated pathway that does not involve macrophage scavenger receptors. Here we report the molecular cloning, using expression cloning strategy, of an Ox-LDL receptor from vascular endothelial cells. The cloned receptor is a membrane protein that belongs structurally to the C-type lectin family, and is expressed in vivo in vascular endothelium and vascular-rich organs.
In a previous study, we demonstrated phenylephrine‐stimulated arachidonic acid (AA) release in rabbit cultured aortic smooth muscle cells. Therefore, we have investigated the functional implications of AA which are involved in the cellular response to phenylephrine, particularly proliferation and migration of rabbit cultured aortic smooth muscle cells.
First, to determine whether AA directly modifies proliferation and mobility of vascular smooth muscle cells (VSMCs), we exposed the cells to AA. AA induced proliferation and migration of the cells in a dose‐dependent fashion. Concomitantly added catalase inhibited the proliferation and chemotaxis induced by AA of VSMCs. Conversely, aminotriazole enhanced the proliferation and migration induced by AA.
Secondly, we investigated whether the proliferation and migration of VSMCs by phenylephrine were related to AA and hydrogen peroxide (H 2 O 2 ). The proliferation and chemotaxis of VSMCs by phenylephrine were inhibited by a phospholipase A 2 (PLA 2 ) inhibitor, or catalase.
Lastly, we investigated the effects of AA and phenylephrine on the content of H 2 O 2 in VSMCs. AA and phenylephrine treatment led to an increase of H 2 O 2 in a dose‐dependent manner.
These results suggest that the addition of phenylephrine to the cells caused the enhancement of proliferation and migration, probably by mediating AA release and reactive oxygen species (ROS) production.
British Journal of Pharmacology (1997) 121 , 665–670; doi: 10.1038/sj.bjp.0701171
Endothelial dysfunction, or activation, elicited by oxidized LDL (Ox-LDL) or its lipid constituent, has been implicated in the initiation and progression of atherosclerosis. We have recently identified a C-type lectin-like molecule, designated lectin-like Ox-LDL receptor-1 (LOX-1), which acts as a cell-surface receptor for Ox-LDL in cultured vascular endothelial cells. In this study, we provide evidence that LOX-1 expression can be upregulated by tumor necrosis factor-alpha (TNF-alpha) and phorbol 12-myristate 13-acetate (PMA) in cultured bovine aortic endothelial cells. TNF-alpha and PMA upregulated LOX-1 protein and mRNA in a time- and dose-dependent manner. Nuclear runoff assay revealed that TNF-alpha stimulates transcription of the LOX-1 gene. Chinese hamster ovary K1 cells stably expressing LOX-1 internalized 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled Ox-LDL but did not significantly internalize acetylated LDL (Ac-LDL), which was effectively suppressed by excess amounts of unlabeled Ox-LDL but not by Ac-LDL. Upregulated expression of LOX-1 by TNF-alpha and PMA was associated with increased uptake of DiI-Ox-LDL that cannot be blocked by excess amounts of unlabeled Ac-LDL. Taken together, LOX-1 is a receptor specific for Ox-LDL, and enhanced uptake of Ox-LDL via this novel receptor on vascular endothelial cells may play an important role in endothelial activation in atherogenesis.
The role of reactive oxygen species, such as superoxide anions (O(2). (-)) and hydrogen peroxide (H(2)O(2)), in modulating vascular smooth muscle cell proliferation and viability is controversial. To investigate the role of endogenously produced H(2)O(2), rat aortic smooth muscle cells were infected with adenoviral vectors containing cDNA for human catalase (AdCat) or a control gene, beta-galactosidase (AdLacZ). Infection with AdCat resulted in dose-dependent increases in intracellular catalase protein, which was predominantly localized to peroxisomes. After infection with 100 multiplicity of infection (MOI) of AdCat, cellular catalase activity was increased by 50- to 100-fold, and intracellular H(2)O(2) concentration was reduced, as compared with control. Infection with AdCat reduced [(3)H]thymidine uptake, an index of DNA synthesis, in cells maintained in medium supplemented with 2% serum (0.37+/-0.09 disintegrations per minute per cell [AdLacZ] versus 0.22+/-0.08 disintegrations per minute per cell [AdCat], P<0.05). Five days after infection with 100 MOI of AdCat, cell numbers were reduced as compared with noninfected or AdLacZ-infected cells (157 780+/-8413 [AdCat], P<0.05 versus 233 700+/-3032 [noninfected] or 222 410+/-5332 [AdLacZ]). Furthermore, the number of apoptotic cells was increased 5-fold after infection with 100 MOI of AdCat as compared with control. Infection with AdCat resulted in induction of cyclooxygenase (COX)-2, and treatment with a COX-2 inhibitor overcame the AdCat-induced reduction in cell numbers. These findings indicate that overexpression of catalase inhibited smooth muscle proliferation while increasing the rate of apoptosis, possibly through a COX-2-dependent mechanism. Our results suggest that endogenously produced H(2)O(2) importantly modulates survival and proliferation of vascular smooth muscle cells.
Oxidative stress and the production of intracellular reactive oxygen species (ROS) have been implicated in the pathogenesis of a variety of diseases. In excess, ROS and their byproducts that are capable of causing oxidative damage may be cytotoxic to cells. However, it is now well established that moderate amounts of ROS play a role in signal transduction processes such as cell growth and posttranslational modification of proteins. Oxidants, antioxidants, and other determinants of the intracellular reduction-oxidation (redox) state play an important role in the regulation of gene expression. Recent insights into the etiology and pathogenesis of atherosclerosis suggest that this disease may be viewed as an inflammatory disease linked to an abnormality in oxidation-mediated signals in the vasculature. In this review, we summarize the evidence supporting the notion that oxidative stress and the production of ROS function as physiological regulators of vascular gene expression mediated via specific redox-sensitive signal transduction pathways and transcriptional regulatory networks. Elucidating, at the molecular level, the regulatory processes involved in redox-sensitive vascular gene expression represents a foundation not only for understanding the pathogenesis of atherosclerosis and other inflammatory diseases but also for the development of novel therapeutic treatment strategies.
A functional change in the endothelium induced by oxidized low density lipoprotein (OxLDL) and its lipid-constituent, lysophosphatidylcholine (LPC), has been implicated in atherogenesis. Recently, we have cloned lectin-like OxLDL receptor (LOX-1) from bovine aortic endothelial cells (BAE). It is the major binding protein for OxLDL on the surface of BAE and is expressed in atheromatous intima of the human carotid artery as well as in intima of normal bovine aorta. In the present study, we found that OxLDL induced the expression of LOX-1 in BAE. OxLDL upregulated the level of mRNA and protein for LOX-1 in a dose- and time-dependent manner. This induction was blocked by anti-LOX-1 antibody. OxLDL also increased the activity for taking up OxLDL in BAE. Similarly, a major constituent of OxLDL, lysophosphatidylcholine (LPC), induced expression of LOX-1 in mRNA, protein and activity level, suggesting the OxLDL induced expression of LOX-1, at least in part, mediated by LPC. Since LPC did not significantly change the half-life of LOX-1 mRNA, the upregulation seemed to occur at the transcriptional level. These results suggest that LOX-1 is upregulated by the uptake of OxLDL through LOX-1 in atheromatous tissues in vivo, which would further enhance the uptake and endothelial activation and dysfunction.
In this study we examined the effect of oxidized low density lipoprotein (ox-LDL) on the intracellular production of reactive oxygen species (ROS) in bovine aortic endothelial cells (BAECs) and whether this increase occurs through its binding to the endothelial receptor lectin-like ox-LDL receptor-1 (LOX-1). Furthermore, this study also aimed to ascertain whether the binding of ox-LDL to LOX-1 is associated with NF-kappaB activation. ox-LDL induced a significant dose-dependent increase in ROS production after a 30-s incubation with BAECs (p < 0.01). ROS formation was markedly reduced in BAECs incubated with anti-LOX-1 monoclonal antibody (p < 0.001), while control nonimmune IgG produced no effect. ox-LDL induced a time- and dose-dependent significant increase in ROS formation only in CHO-K1 cells stably expressing bovine LOX-1 (p < 0.001), while no increase was present in CHO-K1 cells. The activation of the transcription factor NF-kappaB in BAECs was evident after a 5-min incubation with ox-LDL and was attenuated by anti-LOX-1 monoclonal antibody. The conclusion is that one of the pathophysiological consequences of ox-LDL binding to LOX-1 may be the activation of NF-kappaB through an increased ROS production.
We have recently demonstrated a lectin-like receptor for oxidized (ox)-LDL (LOX-1) in human coronary artery endothelial cells (HCAECs). This receptor is upregulated by ox-LDL. The present study examined the significance of LOX-1 in monocyte adhesion to HCAECs and endothelial injury in response to ox-LDL.
HCAECs were incubated in the presence of antisense oligodeoxynucleotides to the 5'-coding sequence of the human LOX-1 gene (0.5 microm/L). Basal LOX-1 mRNA and protein were suppressed by antisense LOX-1. Ox-LDL-mediated upregulation of LOX-1 was also suppressed by antisense LOX-1. Incubation of HCAECs with ox-LDL (40 microg/mL) for 24 hours markedly increased monocyte chemoattractant protein-1 (MCP-1) mRNA and protein expression as well as monocyte adhesion to HCAECs (P<0.01). After 48 hours of preincubation of HCAECs with antisense LOX-1, ox-LDL-mediated upregulation of MCP-1 and monocyte adhesion to HCAECs both were suppressed (P<0.01), whereas sense LOX-1 had no effect. Whereas antisense or sense LOX-1 alone (both 0.5 nmol/L) did not injure the cells, antisense LOX-1, but not sense LOX-1, reduced ox-LDL-mediated HCAEC injury, determined as LDH release (P<0.01). Activation of mitogen-activated protein kinase (MAPK) may play a critical role in signal transduction in ox-LDL-mediated alteration in MCP-1 expression, since antisense LOX-1, but not the sense LOX-1, completely inhibited the ox-LDL-induced MAPK activation.
These observations with the first use of a specific antisense to human LOX-1 mRNA suggest that LOX-1 is a key factor in ox-LDL-mediated monocyte adhesion to HCAECs.
Emerging evidence indicates that reactive oxygen species, especially superoxide and hydrogen peroxide, are important signaling molecules in cardiovascular cells. Their production is regulated by hormone-sensitive enzymes such as the vascular NAD(P)H oxidases, and their metabolism is coordinated by antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. Both of these reactive oxygen species serve as second messengers to activate multiple intracellular proteins and enzymes, including the epidermal growth factor receptor, c-Src, p38 mitogen-activated protein kinase, Ras, and Akt/protein kinase B. Activation of these signaling cascades and redox-sensitive transcription factors leads to induction of many genes with important functional roles in the physiology and pathophysiology of vascular cells. Thus, reactive oxygen species participate in vascular smooth muscle cell growth and migration; modulation of endothelial function, including endothelium-dependent relaxation and expression of a proinflammatory phenotype; and modification of the extracellular matrix. All of these events play important roles in vascular diseases such as hypertension and atherosclerosis, suggesting that the sources of reactive oxygen species and the signaling pathways that they modify may represent important therapeutic targets.
We demonstrated earlier that angiotensin II (Ang II), by AT(1) receptor activation, upregulates oxidized LDL (ox-LDL) endothelial receptor LOX-1 gene expression and uptake of ox-LDL in human coronary artery endothelial cells (HCAECs). In this study, we investigated the regulation of Ang II receptors (AT1R and AT2R) by ox-LDL and the role of the redox-sensitive transcription factor NF-kappaB in this process.
HCAECs were incubated with ox-LDL for 24 hours. Ox-LDL (10 to 40 microg protein/mL) upregulated AT1R but not AT2R, mRNA, or protein. Ox-LDL degraded IkappaBalpha in cytoplasm and activated transcription factor NF-kappaB (P65) in HCAEC nuclear extract. Treatment of cells with the antioxidant alpha-tocopherol (10 to 50 micromol/L) attenuated ox-LDL-mediated degradation of IkappaBalpha and activation of NF-kappaB (P65) and inhibited the upregulation of AT1R mRNA and protein. The role of NF-kappaB signal transduction was further examined by use of an NF-kappaB inhibitor, caffeic acid phenethyl ester (CAPE). Pretreatment of cells with CAPE inhibited ox-LDL-mediated degradation of IkappaBalpha and NF-kappaB activation and inhibited ox-LDL-induced upregulation of AT1R expression. Incubation of cells with both ox-LDL and Ang II increased cell injury, measured as cell viability and LDH release, compared with either ox-LDL or Ang II alone. alpha-Tocopherol as well as the specific AT1R blocker CV11974 (candesartan) attenuated the cell-injurious effects of ox-LDL.
These observations suggest an important role of ox-LDL-mediated AT1R upregulation in cell injury. In this process, NF-kappaB activation seems to play a critical role in signal transduction. These findings provide a basis for the use of antioxidants and AT1R blockers in designing therapy of atherosclerosis.
The oxygen heterocyclic compounds (coumarins, psoralens and polymethoxylated flavones) present in the nonvolatile residue of the essential oils of Mandarin, Sweet Orange, Bitter Orange, Bergamot and Grapefruit were analysed with an HPLC/API/MS system equipped with an APcI probe in positive mode. The use of hyphenated techniques, such as LC/MS provides a great information about the content and nature of constituents of natural complex matrices, such as essential oils. In this work, MS spectra were recorded at different voltages, to obtain structural information in addition to molecular weight information. The different response of the compounds identified has been also evaluated. The method allowed the confirmation of the identification of the main components of the fraction, previously reported for the different oils. MS characteristics of coumarins, psoralens and polymethoxylated flavones with different substitution patterns were determined on the basis of the response obtained with the APcI interface. Interface parameters were optimised to obtain a contemporaneous response for all the three classes of components.
To test the hypothesis that interleukin-1 receptor antagonist (IL-1ra) gene polymorphism contributes to the risk of restenosis after coronary stenting.
Cytokines of the interleukin-1 (IL-1) family play a central role in regulating inflammatory responses. There is strong evidence to support IL-1 involvement in smooth muscle cell mitogenesis and extracellular matrix metabolism. The IL-1ra counters the proinflammatory effects of IL-1. The interleukin-1 receptor antagonist gene (IL-1RN) contains several well-characterized polymorphic sites that correlate with altered IL-lra levels.
In 1,850 consecutive patients, clinical and angiographic measures ofrestenosis were evaluated over one year after coronary stent placement. Repeat angiography at six months was achieved in 84% of the patients; angiographic restenosis was defined < or =50% diameter stenosis at follow-up. Genotyping for an exon 2 polymorphism (+2,018) of IL-1RN (alleles 1 and 2) was based on a polymerase chain reaction technique.
Allele 2 frequency was 0.28. Carriers of allele 2 had a significantly lower risk for angiographic restenosis, odds ratio (OR) of 0.78 (95% confidence interval, 0.63 to 0.97) and target vessel revascularization, OR of 0.73 (0.58 to 0.92) compared with noncarriers. Risk reduction was especially significant in patients <60 years (n = 696), with OR of 0.63 (0.43 to 0.91) for angiographic restenosis and 0.55 (0.39 to 0.78) for target vessel revascularization.
Allele 2 of the IL-1ra gene was associated with a lower incidence of restenosis after coronary stenting, particularly in younger patients. This finding supports a role of inflammation in the development of restenosis after stent placement.