A 2×2 factorial design was used to evaluate possible preservation
of mitochondrial functions in two cardioprotective experimental models, remote ischemic preconditioning and streptozotocin-induced diabetes mellitus, and their interaction during ischemia/reperfusion injury (I/R) of the heart. Male Wistar rats were randomly allocated into four groups: control (C), streptozotocin-induced diabetic (DM), preconditioned
(RPC) and preconditioned streptozotocin-induced diabetic (DM+RPC).
RPC was conducted by 3 cycles of 5-min hind-limb ischemia and 5-min reperfusion. DM was induced by a single dose of 65mg/kg streptozotocin. Isolated hearts were exposed to ischemia/reperfusion test according to Langendorff. Thereafter mitochondria were isolated and the mitochondrial respiration was measured. Additionally, the ATP synthase activity measurements on the same preparations were done. Animals of all groups subjected to I/Rexhibited a decreased state 3 respiration with the least change noted in DM+RPC group associated with no significant changes in state 2 respiration. In RPC, DM and DM+RPC group, no significant
changes in the activity of ATP synthase were observed after I/R
injury. These results suggest that the endogenous protective mechanisms of RPC and DM do preserve the mitochondrial function in heart when they act in combination.
Quercetin, a polyphenolic compound present in various types of food, has been shown to exert beneficial effects in different cardiac as well as non-cardiac ischemia/reperfusion (I/R) models in adult animals. However, there is no evidence about the effects of quercetin on I/R injury in non-mature animals, despite the fact that efficiency of some interventions against I/R is agedependent. This study was aimed to investigate the effects of chronic quercetin treatment on I/R injury in juvenile and adult rat hearts. Juvenile (4-week-old) as well as adult (12-week-old) rats were treated with quercetin (20 mg/kg/day) for 4 weeks, hearts were excised and exposed to 25-min global ischemia followed by 40-min reperfusion. Functional parameters of hearts and occurrence of reperfusion arrhythmias were registered to assess the cardiac function. Our results have shown that quercetin improved post-ischemic recovery of LVDP, as well as recovery of markers of contraction and relaxation, +(dP/dt)max and -(dP/dt)max, respectively, in juvenile hearts, but not in adult hearts. Quercetin had no impact on incidence as well as duration of reperfusion arrhythmias in animals of both ages. We conclude that the age of rats plays an important role in heart response to quercetin treatment in the particular dose and duration of the treatment. Therefore, the age of the treated subjects should be taken into consideration when choosing the dose of quercetin and duration of its application in prevention and/or treatment of cardiovascular diseases., M. Bartekova, J. Radosinska, D. Pancza, M. Barancik, T. Ravingerova., and Obsahuje bibliografii
The objectives of this study were to investigate the role of
endogenous opioids in the mediation of stress-induced
cardiomyopathy (SIC), and to evaluate which opioid receptors
regulate heart resistance to immobilization stress. Wistar rats
were subjected to 24 h immobilization stress. Stress-induced
heart injury was assessed by 99mTc-pyrophosphate accumulation
in the heart. The opioid receptor (OR) antagonists (naltrexone,
NxMB – naltrexone methyl bromide, MR 2266, ICI 174.864) and
agonists (DALDA, DAMGO, DSLET, U-50,488) were administered
intraperitoneally prior to immobilization and 12 h after the start
of stress. In addition, the selective µ OR agonists PL017 and
DAMGO were administered intracerebroventricularly prior to
stress. Finally pretreatment with guanethidine was used.
Naltrexone did not alter the cardiac 99mTc-PP accumulation in
stressed rats. NxMB aggravated stress-induced cardiomyopathy
(P=0.005) (SIC). The selective µ OR agonist DALDA, which does
not cross the blood-brain barrier, completely prevented
(P=0.006) SIC. The µ OR agonist DAMGO exhibited weaker effect
than DALDA. The selective δ ligand (DSLET) and κ OR ligand
(U-50,488) did not alter stress-induced 99mTc-pyrophosphate
accumulation in the heart. Intracerebroventricular administration
of the µ OR agonists aggravated SIC. Pretreatment with
guanethidine abolished this effect (P=0.01). Guanethidine alone
exhibited cardioprotective properties. A stimulation of central
µ OR promotes an appearance of SIC. In contrast, stimulation of peripheral µ OR contributes to an increase in cardiac tolerance to
stress
Cardiovascular disease (CVD) and depressive disorders (DD) are two of the most prevalent health problems in the world. Although CVD and depression have different origin, they share some common pathophysiological characteristics and risk factors, such as the increased production of proinflammatory cytokines, endothelial dysfunction, blood flow abnormalities, decreased glucose metabolism, elevated plasma homocysteine levels, oxidative stress and disorder in vitamin D metabolism. Current findings confirm the common underlying factors for both pathologies, which are related to dramatic dietary changes in the mid-19th century. By changing dietary ratio of omega-6 to omega-3 fatty acids from 1:1 to 15-20:1 some changes in metabolism were induced, such as increased pro-inflammatory mediators and m odulations of different signaling pathways following pathophysiological response related to both, cardiovascular diseases and depressive disorders., J. Trebatická, A. Dukát, Z. Ďuračková, J. Muchová., and Obsahuje bibliografii
Gasotransmitters represent a subfamily of the endogenous gaseous signaling molecules that include nitric oxide (NO), carbon monoxide
(CO), and hydrogen sulphide (H2S). These particular gases share many common features in their production and function, but they fulfill their physiological tasks in unique ways that differ from those of classical signaling molecules found in tissues and organs. These gasotransmitters may antagonize or potentiate each other’s cellular effects at the level of their production, their downstream molecular targets and their direct
interactions. All three gasotransmitters induce vasodilatation, inhibit apoptosis directly or by increasing the expression of anti-apoptotic genes, and activate antioxidants while inhibiting inflammatory actions. NO and CO may concomitantly participate in vasorelaxation, anti-inflammation and angiogenesis. NO and H2S collaborate in the regulation of vascular tone. Finally, H2S may upregulate the heme oxygenase/carbon monoxide
(HO/CO) pathway during hypoxic conditions. All three gasotransmitters are produced by specific enzymes in different cell types that include cardiomyocytes, endothelial cells and smooth muscle cells. As translational research on gasotransmitters has exploded over the past years, drugs that alter the production/levels of the gasotransmitters themselves or
modulate their signaling pathways are now being developed. This review is focused on the cardiovascular effects of NO, CO, and H2S. Moreover, their donors as drug targeting the cardiovascular system are briefly described.
In this study we set out to understand is sleep fragmentation affects the cardiovascular regulation and circadian variability of core body temperature more or less than sleep deprivation. 50 healthy men (age 29.0±3.1 years; BMI 24.3±2.1 kg/m2) participated in a 3-day study that included one adaptative night and one experimental night involving randomization to: sleep deprivation (SD) and sleep fragmentation (SF). The evaluation included hemodynamic parameters, measures of the spectral analysis of heart rate and blood pressure variability, and the sensitivity of arterial baroreflex function. Core body temperature (CBT) was measured with a telemetric system. SF affects heart rate (61.9±5.6 vs. 56.2±7.6, p<0.01) and stroke index (52.7±11.1 vs. 59.8±12.2, p<0.05) with significant changes in the activity of the ANS (LF-sBP: 6.0±5.3 vs. 3.4±3.7, p<0.05; HF-sBP: 1.8±1.8 vs. 1.0±0.7, p<0.05; LF-dBP: 5.9±4.7 vs. 3.5±3.2, p<0.05) more than SD. Post hoc analysis revealed that after SD mean value of CBT from 21:30 to 06:30 was significantly higher compared to normal night’s sleep and SF. In healthy men SF affects the hemodynamic and autonomic changes more than SD. Sympathetic overactivity is the proposed underlying mechanism., J. Słomko, M. Zawadka-Kunikowska, J. J. Klawe, M. Tafil-Klawe, J. Newton, P. Zalewski., and Obsahuje bibliografii
The altered regulation of autonomic response to mental stress can result in increased cardiovascular risk. The laboratory tests used to simulate the autonomic responses to real-life stressors do not necessarily induce generalized sympathetic activation; therefore, the assessment of regulatory outputs to different effector organs could be important. We aimed to study the cardiovascular sympathetic arousal in response to different mental stressors (Stroop test, mental arithmetic test) in 20 healthy students. The conceivable sympathetic vascular index - spectral power of low frequency band of systolic arterial pressure variability (LF-SAP) and novel potential cardiosympathetic index - symbolic dynamics heart rate variability index 0V% were evaluated. The heart and vessels responded differently to mental stress - while Stroop test induced increase of both 0V% and LF-SAP indices suggesting complex sympathetic arousal, mental arithmetic test evoked only 0V% increase compared to baseline (p<0.01, p<0.001, p<0.01, respectively). Significantly greater reactivity of LF-SAP, 0V%, heart rate (HR) and mean arterial pressure (MAP) were found in response to Stroop test compared to mental arithmetic test potentially indicating the effect of different central processing (0V%, LF-SAP: p<0.001; HR, MAP: p<0.01). The different effectors’ sympathetic responses to cognitive stressors could provide novel important information regarding potential pathomechanisms of stress-related diseases., M. Mestanik, A. Mestanikova, Z. Visnovcova, A. Calkovska, I. Tonhajzerova., and Obsahuje bibliografii
A new species of the Carex flava complex (Cyperaceae) is described from the Czech Republic. It is known only from the type locality and is assumed to be endemic to the Krkonoše Mts. Its systematic position along with karyological and ecological notes are presented here. The new entity proposed, Carex derelicta, is included in the subsection Serotinae of the section Ceratocystis. The distinctive features of this species are its combination of globose to shortly cylindrical female spikes, glumes of female spikes equalling or exceeding the perigynia; perigynia 2.0–2.5 mm long, not inflated, vivid green, beaks 0.4–0.7 mm long and achenes completely filling perigynia. The chromosome number n = 35 is the first reported for this taxon.
Morphological variation of Carex muricata from 232 localities in the Czech Republicwas analysed. The plants were preliminarily classified using qualitative characters into six species: C. contigua, C. muricata, C. pairae, C. chabertii, C. divulsa, and C. leersiana. Of 27 quantitative characters, all were used in a principal components analysis and 25 in a discriminant analysis. Both analyses were done using the data for all the species and then separately for the taxonomically complicated species pairs. In the discriminant analysis, the most useful characters for separating particular species were selected; they included the distance between the first and second lowermost spike of the infructescence, infructescence length, glume length in pistillate flower, achene length, length of perigynium beak and spike size. In the classification discriminant analysis, with the six most important characters, 94.4% of plants were correctly classified to the designated groups. The analysis showed that some species pairs (C. muricata – C. pairae, C. chabertii – C. leersiana) are only partially distinguished by quantitative morphological characters. Some other species (C. contigua, C. divulsa), however, are well differentiated and easily identified.