Jitka Zurmanova

Charles University in Prague | CUNI · Department of Physiology, Faculty of Science, Charles University in Prague

The mammalian body possesses remarkable adaptability to cold exposure, involving intricate adjustments in cellular metabolism, ultimately leading to thermogenesis. However, cold‐induced stress can impact immune response, primarily through noradrenaline‐mediated pathways. In our study, we utilized a rat model subjected to short‐term or long‐term mil...

Moderate cold acclimation (MCA) is a non-invasive intervention mitigating effects of various pathological conditions including myocardial infarction. We aim to determine the shortest cardioprotective regimen of MCA and the response of β1/2/3-adrenoceptors (β-AR), its downstream signaling, and inflammatory status, which play a role in cell-survival...

Nestin is a unique intermediate filament expressed for a short period in the developing heart. It was also documented in several cell types of the adult myocardium under pathological conditions such as myocardial infarction or fibrosis. However, circumstances of nestin re-occurrence in the diseased or aging heart have not been elucidated yet. In th...

Light pollution disrupts circadian rhythms that may promote obesity and hypertension, but their association with the susceptibility to malignant cardiac arrhythmias is not well known. We examined whether continuous light as well as a high sucrose diet affect rat heart gene transcripts, miRNAs, or protein expression and hence arrhythmogenesis. In pa...

Desmin mutations cause familial and sporadic cardiomyopathies. In addition to perturbing the contractile apparatus, both desmin deficiency and mutated desmin negatively impact mitochondria. Impaired myocardial metabolism secondary to mitochondrial defects could conceivably exacerbate cardiac contractile dysfunction. We performed metabolic myocardia...

Funding Acknowledgements Type of funding sources: None. Light pollution disrupts circadian rhythms and increases the development of obesity, but their connection to cardiovascular disease, in particular to malignant arrhythmias, is not well known. Herein, we investigated if female rats exposed to continuous light and high-sucrose diet had altered m...

Objective: Light pollution disturbs circadian rhythm, and this can also be deleterious to the heart by increased susceptibility to arrhythmias. Herein, we investigated if rats exposed to continuous light had altered myocardial gene transcripts and/or protein expression which affects arrhythmogenesis. We then assessed if Omacorâ supplementation ben...

Mitochondrial retrograde signaling is a pathway of communication from mitochondria to the nucleus. Recently, natural mitochondrial genome (mtDNA) polymorphisms (haplogroups) received increasing attention in the pathophysiology of human common diseases. However, retrograde effects of mtDNA variants on such traits are difficult to study in humans. Th...

Light pollution disturbs circadian rhythm, and this can also be deleterious to the heart by increased susceptibility to arrhythmias. Herein, we investigated if rats exposed to continuous light had altered myocardial gene transcripts and/or protein expression which affects arrhythmogenesis. We then assessed if Omacor® supplementation benefitted affe...

Despite the recent progress in research and therapy, cardiovascular diseases are still the most common cause of death worldwide, thus new approaches are still needed. The aim of this review is to highlight the cardioprotective potential of urocortins and corticotropin-releasing hormone (CRH) and their signaling. It has been documented that urocorti...

The infarct size-limiting effect elicited by cold acclimation (CA) is accompanied by increased mitochondrial resistance and unaltered β 1 -adrenergic receptor (AR) signaling persisting for two weeks at room temperature. As the mechanism of CA-elicited cardioprotection is not fully understood we examined the role of the salvage β 2 -AR/Gi/Akt pathwa...

Novel strategies are needed that can stimulate endogenous signaling pathways to protect the heart from myocardial infarction. The present study tested the hypothesis that appropriate regimen of cold acclimation (CA) may provide a promising approach for improving myocardial resistance to ischemia/reperfusion (I/R) injury without negative side effect...

Heart function and its susceptibility to arrhythmias are modulated by thyroid hormones (THs) but the responsiveness of hypertensive individuals to thyroid dysfunction is elusive. We aimed to explore the effect of altered thyroid status on crucial factors affecting synchronized heart function, i.e., connexin-43 (Cx43) and extracellular matrix protei...

Remodeling of the cellular distribution of gap junctions formed mainly by connexin-43 (Cx43) can be related to the increased incidence of cardiac arrhythmias. It has been shown that adaptation to chronic intermittent hypobaric hypoxia (IHH) attenuates the incidence and severity of ischemic and reperfusion ventricular arrhythmias and increases the p...

Adaptation to continuous normobaric hypoxia (CNH) protects the heart against acute ischemia/reperfusion injury. Recently, we have demonstrated the infarct size-limiting effect of CNH also in hearts of spontaneously hypertensive rats (SHR) and in conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR...

Cold acclimation is characterized by shift from shivering to non-shivering thermogenesis during exposure to cold which is mediated by adrenergic signalling. It has been also shown that cold acclimation increases organismal resistance to different pathological stimuli and in man may affect functional parameters of the cardiovascular system mediated...

Cold acclimation or hardening is a well-known intervention increasing organismal resistance to different pathological stimuli1. It has been shown that cold acclimation in man may affect functional parameters of the cardiovascular system mediated by adrenergic β-receptors (β-ARs)1,2, however the molecular mechanism and possible role of cold acclimat...

Hypertension, dyslipidemia, and insulin resistance in the spontaneously hypertensive rat (SHR) can be alleviated by rescuing CD36 fatty acid translocase. The present study investigated whether transgenic rescue of CD36 in SHR could affect mitochondrial function and activity of selected metabolic enzymes in the heart. These analyses were conducted o...

Cold acclimation or hardening is a well-known intervention increasing organismal resistance to different pathological stimuli1. It has been shown that cold acclimation in man may affect functional parameters of the cardiovascular system mediated by adrenergic β-receptors (β-ARs)2, but the molecular mechanism underlying this phenomena is not fully u...

Adaptation to chronic hypoxia represents a potential cardioprotective intervention reducing the extent of acute ischemia/reperfusion (I/R) injury, which is a major cause of death worldwide. The main objective of this study was to investigate the anti-apoptotic Akt/hexokinase 2 (HK2) pathway in hypoxic hearts subjected to I/R insult. Hearts isolated...

The β-adrenergic signaling pathways and antioxidant defence mechanisms play important roles in maintaining proper heart function. Here, we examined the effect of chronic normobaric hypoxia (CNH, 10% O2, 3 weeks) on myocardial β-adrenergic signaling and selected components of the antioxidant system in spontaneously hypertensive rats (SHR) and in a c...

Adaptation to chronic intermittent hypoxia (CIH) is associated with reactive oxygen species (ROS) generation implicated in the improved cardiac tolerance against acute ischemia–reperfusion injury. Phospholipases A2 (PLA2s) play an important role in cardiomyocyte phospholipid metabolism influencing membrane homeostasis. Here we aimed to determine th...

Mitochondria play an essential role in improved cardiac ischemic tolerance conferred by adaptation to chronic hypoxia. In the present study, we analyzed effects of continuous normobaric hypoxia (CNH) on mitochondrial functions, including the sensitivity of mitochondrial permeability transition pore (MPTP) to opening, and infarct size in hearts of s...

We aimed to study the impact of altered thyroid status on myocardial expression of electrical coupling protein connexin-43 (Cx43), the susceptibility of rats to ventricular fibrillation (VF) and the effects of antioxidant-rich red palm oil (RPO). Adult male and female euthyroid, hyperthyroid (treated with T3/T4), hypothyroid (treated with methimazo...

Cardiac resistance against acute ischemia/reperfusion (I/R) injury can be enhanced by adaptation to chronic intermittent hypoxia (CIH), but the changes at the molecular level associated with this adaptation are still not fully explored. Phospholipase A2 (PLA2) plays an important role in phospholipid metabolism and may contribute to membrane destruc...

Introduction - Despite the progress in the research and therapy, cardiovascular diseases are still the most common cause of death worldwide. Cold acclimation or hardening has a good potential for attenuation of cardiovascular risks (1). Parameters, of mitochondrial respiration in long-term cold acclimated heart have not been studied yet. Materials...

Chronic hypoxia may produce a cardioprotective phenotype characterized by increased resistance to ischemia-reperfusion injury. Nevertheless, the molecular basis of cardioprotective effects of hypoxia is still not quite clear. The present study investigated the consequences of a 3-week adaptation to cardioprotective (CNH, continuous normobaric hypox...

Dexras1 has been shown to exhibit clock-dependent rhythm in mice suprachiasmatic nucleus (SCN), and its genetic deletion modulates circadian responses to photic and nonphotic cues. We show that the rhythmic expression of Dexras1 mRNA and protein in rat SCN already oscillates with low amplitude at postnatal day 3 and can be detected as early as embr...

It has been documented that adaptation to hypoxia increases myocardial tolerance to ischemia/reperfusion (I/R) injury depending on the regimen of adaptation. Reactive oxygen species (ROS) formed during hypoxia play an important role in the induction of protective cardiac phenotype. On the other hand, the excess of ROS can contribute to tissue damag...

Chronic hypoxia increases the myocardial resistance to acute ischemia-reperfusion injury by affecting the mitochondrial redox balance. Hexokinase (HK) bears a high potential to suppress the excessive formation of reactive oxygen species due to its increased association with mitochondria, thereby inhibiting the membrane permeability transition pore...

Continuous normobaric hypoxia (CNH) renders the heart more tolerant to acute ischemia/reperfusion injury. Protein kinase C (PKC) is an important component of the protective signaling pathway, but the contribution of individual PKC isoforms under different hypoxic conditions is poorly understood. The aim of this study was to analyse the expression o...

Purpose: We have shown that long-term adaptation to intermittent normobaric hypoxia (INH) or to intermittent hypobaric hypoxia (IHH) for 8 h per day improves myocardial tolerance to acute ischemia-reperfusion injury. Reactive oxygen species formed during hypoxic exposures play an important role in the induction of protective cardiac phenotype. Meth...

Purpose: Adaptation to continuous normobaric hypoxia (CNH) increases cardiac ischemic tolerance. The protective role of cardiac mitochondria has been suggested in CNH. The present study investigated the effects of CNH on the expression and activity of selected mitochondrial proteins in spontaneously hypertensive rats (SHR), and in a novel conplasti...

Background and purpose: The cardiovascular system is modulated by thyroid hormones and their deficiency or excess in hypo- (HY) or hyperthyroid (TH) status may affect both cardiac function and arrhythmogenesis. We hypothesized that intercellular communication via connexin-43 (Cx43) channels might be implicated. The goal of this study was to explore...

Purpose: Spontaneously hypertensive rats (SHR) are more susceptible to acute myocardial ischemia/ reperfusion injury than normotensive Brown Norway (BN) strain. It has been shown that the adaptation to chronic hypoxia improves ischemic tolerance in normotensive rats and the cardioprotective phenotype can be related to mitochondrial metabolism and s...

Background and Purpose: Melatonin in addition to regulation of circadian rhythm exhibits antihypertensive, free radicals scavenging and antiarrhythmic effects as we have shown recently. While melatonin deficiency and lower omega-3 index observed in pts suffering from CHD and hypertension as well as in SHR can contribute to disease progression and p...

Purpose: Creatine kinase (CK) and hexokinase (HK) play a key role in energy homeostasis of cardiomyocytes. Mitochondrial sarcomeric CK (mtCKs) and two hexokinase isoforms (HK1 and HK2) highly support mitochondrial oxidative phosphorylation by increasing the availability of ADP for complex V of the respiratory chain. Besides the mtCKs, there are two...

The effect of adaptation to chronic continuous hypoxia (CCH) on cardiac ischemic tolerance and the expression of selected mitochondrial proteins, antioxidative enzymes and signalling molecules were analysed in left ventricles of spontaneously hypertensive rats (SHR) and in a novel conplastic strain SHR‐mt BN . These animals are characterized by a s...

Background: Creatine kinase (CK) and hexokinase (HK) play a key role in myocardial energy homeostasis. We aimed to determine CK and HK expression and enzyme activity in the left (LV) and right (RV) ventricles of rats adapted for 3 weeks to normobaric hypoxia (10 % O2) either continuously (CNH) or intermittently with 1-h or 16-h normoxic episode pe...

Objective: Hypertension-induced myocardial remodelling is known to be associated with increased risk of malignant arrhythmias and alterations in electrical coupling protein, connexin-43 (Cx43), may be involved in the pathogenesis. We investigated whether omega-3 fatty acids intake affects abnormalities of Cx43 as well as protein kinase C (PKC) sign...

Background and purpose: Hypertension if not properly controlled is deleterious to health due to inflammation, myocardial remodelling and autoantibody (AAB) production. Consequently, it facilitates heart failure and incidence of lethal arrhythmias. Clinical and experimental studies, including ours, indicate cardio-protective effects of omega-3 fatty...

Objective: Hypertension-induced myocardial remodeling is known to be associated with increased risk for malignant arrhythmias and alterations in electrical coupling protein, connexin-43 (Cx43), may be involved. We investigated whether omega-3 fatty acids intake affects abnormalities of Cx43 as well as protein kinase C (PKC) signaling and myosin he...

Dysfunction or abnormalities in the regulation of fatty acid translocase Cd36, a multifunctional membrane protein participating in uptake of long-chain fatty acids, has been linked to the development of heart diseases both in animals and humans. We have previously shown that the Cd36 transgenic spontaneously hypertensive rat (SHR-Cd36), with a wild...

We studied the expression of myosin heavy chain isoforms at mRNA and protein levels as well as fiber type composition in the fast extensor digitorum longus (EDL) and slow soleus (SOL) twitch muscles of adult inbred Lewis strain rats. Comparison of the results from Real Time RT-PCR, SDS-PAGE and fiber type analysis showed corresponding proportions o...

Background/Aims: Hexokinase (HK) is a key glycolytic enzyme which promotes the maintenance of glucose homeostasis in cardiomyocytes. HK1 isoform is predominantly bound to the outer mitochondrial membrane and highly supports oxidative phosphorylation by increasing the availability of ADP for complex V of the respiratory chain. HK2 isoform is under p...

The expression of two cardiac myosin heavy chain (MyHC) isoforms in response to the thyroid status was studied in left ventricles (LVs) of Lewis rats. Major MyHC isoform in euthyroid and hyperthyroid LVs had a higher mobility on SDS-PAGE, whereas hypothyroid LVs predominantly contained a MyHC isoform with a lower mobility corresponding to that of t...

In order to re-evaluate the presence and relative quantity of 2b and 2x/d myosin heavy chain (MyHC) transcripts in rat slow soleus muscle by using real time RT-PCR we have compared the available relevant cDNA sequences and designed a new set of primers having similar melting temperatures, matching separate MyHC exons in the regions of maximal diffe...

Myofibrillar creatine kinase (CK) buffers the cellular ATP concentration during fluctuating ATP turnover in a muscle. In order to detect structural changes of the CK molecule due to bound substrates, the dynamics of free, ATP-bound, and ATP+creatine-bound CK were examined, using steady-state and time-resolved fluorescence spectroscopy. The intrinsi...

Creatine kinase (CK) (E.C. 2.7.3.2) buffers cellular ATP concentration during fluctuating ATP turnover. Muscle cytosolic CK isoform interacts with various subcellular structures where it is functionally coupled with relevant ATPases. However, how this interaction affects its activity is not known. We have therefore studied the interaction of CK wit...

We have separated 2b myosin heavy chain (MyHC) isoform from the rat extensor digitorum longus muscle by SDS-PAGE and analyzed it by two subsequent mass spectrometry techniques. After tryptic digestion, the obtained peptides were identified by Matrix-Assisted Laser Desorption/Ionisation reflectron Time of Flight mass spectrometry (MALDI-TOF MS) and...

On the basis of previous experience with biological effects of electromagnetic fields a potential effect of homogeneous sinusoidal magnetic field (50 Hz, 10 mT) on energy state of rat skeletal muscle was investigated. Two different total body exposures to magnetic field were selected: (1) repeated 1 hour exposure, 2 times a week for 3 months, and (...

The metabolic turnover in the isolated in vitro perfused and superfused rat skeletal muscle (musculus gracilis cranialis) was enhanced by increasing the medium flow rate under relaxed conditions. In a recent study we have measured the tissue concentrations of second messengers: cyclic adenosine 3'5'-monophosphate (cAMP), cyclic guanosine 3'5'-monop...

The aim of this study was to evaluate myofibrillar creatine kinase (CK) activity and to quantify the substrate channelling of ATP between CK and myosin ATPase under different pH conditions within the integrity of myofibrils. A pure myofibrillar fraction was prepared using differential centrifugation. The homogeneity of the preparation and the purit...

The aim of this study was to evaluate myofibrillar creatine kinase (CK) activity and to quantify the substrate channelling of ATP between CK and myosin ATPase under different pH conditions within the integrity of myofibrils. A pure myofibrillar fraction was prepared using differential centrifugation. The homogeneity of the preparation and the purit...

The aim of this study was to evaluate myofibrillar creatine kinase (EC 2.7.3.2) activity on the background of the effect of substrate channeling by myosin ATPase and to compare it with creatine kinase (CK) activity of whole skinned fibers. In order to assess CK activity, skinned fibers were prepared from the rat psoas major muscles defined by light...