Selenium is a trace element that is essential for living organism. Its beneficial effect is, however, expressed in a very narrow dosage range: the high and low doses of selenium are connected with pathological manifestations. The toxicity depends on the chemical form of selenium, state of organism, interactions with heavy metals and on the stage of ontogenetic development. Whereas one dose of sodium selenite (20 μmol/kg b.w.) is lethal in adult rats, suckling rats are entirely resistant. However, within one week after administration of the same dose, cataract of eye lens developed. The highest incidence of cataract was observed in 10-day-old animals and it decreased until day 20. From postnatal day 20 to day 40 the rats were resistant to both the lethal and cataractogenic effects of selenium. The incidence of cataract may be suppressed by premature weaning, lower hydration of suckling, change of water soluble/water insoluble lens protein ratio, thyroxine treatment, and by interaction with mercury. By means of its oxidative and reduction properties, selenium is involved in the maintenance of the cell redox homeostasis. Typical example is its possible cardioprotective effect: selenium decreased number of arrhythmias, reduced infarct size and improved the contractile recovery after ischemia/reperfusion injury. Selenium supplementation may thus increase cardiac tolerance to ischemic damage., I. Ošťádalová., and Obsahuje seznam literatury
Hospitalized patients in internal medicine have an increased risk of low physical reserve which further declines during the hospital stay. The diagnosis requires bed-side testing of functional domains or more complex investigations of the muscle mass. Clinically useful biomarkers of functional status are needed, thus we aimed to explore the potential of microRNAs. Among hospitalized patients, we recorded the basic demographics, anthropometrics, nutritional status, and physical function domains: hand-grip strength (HGS, abnormal values M<30 kg, W<20 kg), balance (<30 s), chair-stands speed (CHSS<0.5/s) and gait speed (GS<0.8 m/s). A panel of five micro-RNAs (miRNA 1, miRNA 133a, miRNA 133b, miRNA 29a, miRNA 29b) and basic blood biochemistry and vitamin D values were recorded. We enrolled 80 patients (M40, W40), with a mean age of 68.8± 8.4 years. Obesity was observed in 27.5 % and 30 %, low HGS and low CHSS in 65.0, 77.5 %, and 80, 90 % of men and women respectively. The median hospital stay was 6.5 days. MiRNA29a and miRNA29b have the strongest correlation with the triceps skinfold (miRNA 29b, r=0.377, p=0.0006) and CHSS (miRNA 29a, r=0.262, p=0.02). MiRNA 29a, miRNA 29b and 133a levels were significantly higher in patients with CHSS<0.5/s. Other anthropometric parameters, mobility domains, or vitamin D did not correlate. All miRNAs except of miRNA 1, could predict low CHSS (miRNA29b, AUROC=0.736 CI 0.56-0.91, p=0.01), particularly in patients with low HGS (miRNA 29b, AUROC=0.928 CI 0.83-0.98). Among hospitalized patients in internal medicine, low functional status was frequent. MicroRNAs were fair biomarkers of the antigravity domain, but not other domains. Larger studies with clinical endpoints are needed., Petra Vrbová, Simona Valášková, Andrea Gažová, Juraj Smaha, Martin Kužma, Ján Kyselovič, Juraj Payer, Tomáš Koller., and Obsahuje bibliografii
The aim of the study was to compare the bone mineral density (BMD) and body composition between ambulatory male MS patients and control subjects and to evaluate the relationships among body composition, motor disability, glucocorticoids (GC) use, and bone health. Body composition and BMD were measured by dual-energy X-ray absorptiometry in 104 ambulatory men with MS (mean age: 45.2 years) chronically treated with low-dose GC and in 54 healthy age-matched men. Compared to age-matched controls, MS patients had a significantly lower total body bone mineral content (TBBMC) and BMD at all measured sites except for the radius. Sixty five male MS patients (62.5 %) met the criteria for osteopenia and twenty six of them (25 %) for osteoporosis. The multivariate analysis showed a consistent dependence of bone measures (except whole body BMD) on BMI. The total leg lean mass % was as an independent predictor of TBBMC. The Expanded Disability Status Scale (EDSS), cumulative GC dose and age were independent determinants for BMD of the proximal femur. We conclude that decreasing mobility in male MS patients is associated with an increasing degree of osteoporosis and muscle wasting in the lower extremities. The chronic low-dose GC treatment further contributes to bone loss., V. Zikán ... [et al.]., and Obsahuje seznam literatury
Exercise induced bone response although established, little is known about the molecular components that mediate bone response to mechanical loading (ML). In our recent QTL study, we identified one such possible molecular component responding to ML: cartilage oligomeric matrix protein (COMP). To address the COMP role in mediating ML effects on bone formation, COMP expression was evaluated as a function of duration and age in response to ML in female B6 mice. A 9N load was applied using a four-point bending device at 2Hz frequency for 36 cycles, once per day for 2-, 4- and 12-days on the right tibia. The left tibia was used as an internal control. Loading caused an increase in COMP expression by 1.3-, 2- and 4-fold respectively after 2-, 4- and 12-days of loading. This increase was also seen in 16 and 36-week old mice. Based on these findings, we next used COMP knockout (KO) mice to evaluate the cause and effect relationship. Quantitative analysis revealed 2 weeks of ML induced changes in vBMD and bone size in the KO mice (5.9 % and 21 % vs. unloaded bones) was not significantly different from control mice (7 % and 24 % vs. unloaded bones). Our results imply that COMP is not a key upstream mediator of the anabolic effects of ML on the skeleton., A. Sengul, S. Mohan, C. Kesavan., and Obsahuje seznam literatury
Angiotensin converting enzyme (ACE) inhibition has been reported to induce regression of hypertrophy in several models of hemodynamic pressure overload. The aim of the present study was to determine whether the ACE inhibitor captopril can reduce hypertrophy of the left ventricle induced by a chronic volume overload and modify collagen composition of the hypertrophied myocardium. Rabbits with four months lasting aortic insufficiency were divided into two groups: treated with captopril (20 mg/kg/day) for five weeks and treated with placebo. The respective control groups were represented by sham-operated animals. Aortic insufficiency induced a decrease of diastolic pressure, an increase of systolic and pulse pressure, hypertrophy of the left and right ventricle, and an increase of hydroxyproline content in the left ventricle without a change of hydroxyproline concentrations in either ventricle. Captopril treatment further enhanced pulse pressure by decreasing diastolic blood pressure. Hypertrophy of the left ventricle, hydroxyproline content and concentration in both ventricles were unaffected by captopril treatment. It is concluded that ACE inhibition did not reverse the left ventricular hypertrophy developed as a result of overload induced by aortic insufficiency. We suggest that mechanisms different from activation of the renin-angiotensin system may play a decisive role in the maintenance of hypertrophy in this particular model of volume hemodynamic overload., F. Šimko, V. Pelouch, J. Kyselovic., and Obsahuje bibliografii
Hypertension is the risk factor of serious cardiovascular diseases, such as ischemic heart disease and atherosclerosis. The aim of the present study was to analyze the development of cardiac tolerance to ischemia in neonatal spontaneously hypertensive rats (SHR) and possible protective effect of ischemic preconditioning (IP) or adaptation to intermittent high-altitude hypoxia (IHAH). For this purpose we used 1- and 10-day-old pups of SHR and their normotensive control Wistar Kyoto rats (WKY). Isolated hearts were perfused in the Langendorff mode with Krebs-Henseleit solution at constant pressure, temperature and rate. Cardiac tolerance to ischemia was expressed as a percentage of baseline values of developed force (DF) after global ischemia. IP was induced by three 3-min periods of global ischemia, each separated by 5-min periods of reperfusion. IHAH was simulated in barochamber (8 h/day, 5000 m) from postnatal day 1 to 10. Cardiac tolerance to ischemia in 1-day-old SHR was higher than in WKY. In both strains tolerance decreased after birth, and the difference disappeared. The high cardiac resistance in 1- and 10-day-old SHR and WKY could not be further increased by both IP and adaptation to IHAH. It may be concluded that hearts from newborn SHR are more tolerant to ischemia/reperfusion injury as compared to age-matched WKY; cardiac resistance decreased in both strains during the first ten days, similarly as in Wistar rats., Z. Charvátová, ... [et al.]., and Obsahuje seznam literatury
Pyridoxal isonicotinoyl hydrazone (PIH) is a new tridentate Fe-chelating agent that should be very promising in many pathological states resulting from both an iron-overload and formation of free radicals. The aim of our study was to investigate the effect of PIH on the cardiovascular system focusing to the regulatory protein - cardiac troponin T (cTnT). The study was carried out in two groups of Chinchilla male rabbits: 1) PIH (50 mg/kg dissolved in 10 % Cremophor i.p., once a week, 10 administrations, n=8) and 2) Cremophor (2 ml/kg i.p. in the same schedule, n=7). Plasma concentrations of cTnT (as a marker of myocardial damage) were measured using a commercial kit (Roche). cTnT was within the physiological range (i.e. < 0.1 mg/l) during the whole experiment in the Cremophor group. In the PIH group, the cTnT levels were not significantly increased when compared with the control group or with the initial values (except with those before the 5th administration). Furthermore, we analyzed the cytosolic and myofibrillar fraction of cTnT in the left ventricular myocardium. Using SDS-PAGE and Western blot we resolved three isoforms. The profiling of TnT did not differ significantly between the PIH-treated group and the Cremophor-treated group. Our data concerning cTnT support the opinion that the possible cardiotoxicity of PIH is very low., M. Adamcová, J. Macháčková, V. Geršl, V. Pelouch, T. Šimůnek, I. Klimtová, R. Hrdina, P. Poňka., and Obsahuje bibliografii
This study was undertaken to examine the effects of dietary supplementation of cysteine and taurine in rats with diabetes induced with streptozotocin (STZ, 65 mg/kg body weight). Experimental animals were treated orally (by gavage) with cysteine (200 mg/kg) and taurine (400 mg/kg), alone or in combination, daily for 8 weeks. In one group, rats were also pretreated 3 weeks before the induction of diabetes (prevention arm) whereas in the other, the treatment was started 3 days after the induction of diabetes (reversal arm). Diabetes increased heart weight/body weight (HW/BW) ratio, plasma glucose, triglyceride and cholesterol levels as well as depressed heart rate (HR), blood pressure, left ventricular systolic pressure (LVSP), rate of contraction (+dP/dt), rate of relaxation (-dP/dt), fractional shortening (FS) and cardiac output (CO). The left ventricular internal diameter in systole (LViDs) was increased whereas that in diastole (LViDd) was decreased. In the prevention arm, treatment of the diabetic animals with cysteine or taurine decreased HW/BW ratio and improved HR, FS, +dP/dt and -dP/dt, as well as normalized LViDs, without altering the increase in glucose level. Cysteine decreased plasma triglyceride and cholesterol levels and improved LVSP whereas CO was improved by taurine. In the reversal arm, cysteine alone or with taurine did not correct the changes in hemodynamic parameters, FS and plasma triglycerides. Diabetes-induced cardiac dysfunction and increases in plasma triglycerides can be prevented, but not reversed, by dietary cysteine alone or in combination with taurine., P. S. Tappia, ... [et al.]., and Obsahuje seznam literatury
The aim of our study was to evaluate a possible association between microalbuminuria (MA), several low-grade inflammation factors and left ventricular hypertrophy (LVH) by using a pharmacological approach. This may provide new insights into the pathophysiologic mechanisms of the cardiorenal syndrome (CRS) linking early renal impairment with elevated cardiovascular risk. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (220-250 g). After the development of hypertension, rats were divided into four groups: 2K-1C (untreated), calcium channel blocker (amlodipine-treated), angiotensin receptor blocker (losartan-treated) and peripheral vasodilator (hydralazine-treated), which were treated for 10 weeks. Rats in the 2K-1C group had all developed hypertension, a significant increase in plasma levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), brain natriuretic peptide (BNP) and C-reactive protein (CRP). Moreover MA and creatininaemia underwent a significant increase. Under treatment decreases were observed in systolic blood pressure (SBP), TNF-α, CRP, IL-6, BNP concentrations and creatininaemia. These results were related to the absence of MA which was significantly associated with reductions in cardiac mass and hypertrophy markers (BNP and β-MHC gene expression) as well as renal interstitial inflammation. In conclusion, our results suggest that the reduction of MA is correlated with the decrease of the inflammatory components and seems to play an important role in protecting against cardiac hypertrophy and renal injury., M. Moubarak , H. Jabbour , V. Smayra , E. Chouery , Y. Saliba , V. Jebara , N. Farés., and Obsahuje seznam literatury
a1_The question was addressed of how nitric oxide synthase (NO synthase) inhibition-induced hypertension in rat parents would affect the cardiovascular system in their offsprings. Two experimental groups were set up: Group I - offsprings of parents who had both been administered NO synthase inhibitor L-nitro-arginine methyl ester (L-NAME 40 mg/kg/day) for 5 weeks, the treatment of dams continued till week 12. Group II - offsprings fed by dams administered L-NAME after delivery only for a period of 4 weeks. Control age-matched offsprings formed the third group. Blood pressure and heart rate in parents and in 3-week-old offsprings were determined noninvasively. In the offsprings, body and heart weight were measured and the heart/body weight ratio (HW/BW) was calculated. The NO synthase activity, and also ornithine decarboxylase activity as a marker of polyamine production, were determined in the heart. The acetylcholine-induced relaxation of aortic rings was also followed. A marked blood pressure increase with a tendency to a decreased heart rate was found in the offsprings of Group I. A significant decrease in heart weight and body weight with a decreased HW/BW ratio indicated cardiac hypotrophy that contrasted with the decrease in NO synthase activity and increase in ornithine decarboxylase activity in the heart. Noteworthy was also the finding of completely preserved relaxation of the aorta to acetylcholine. Offsprings of Group II were similarly characterized by significantly higher blood pressure, a tendency to decreased heart rate, a decrease in heart weight, but not of the HW/BW ratio. The contrasting findings of heart weight decrease on the one hand and NO synthase activity decrease and ornithine decarboxylase increase on the other, were also found in this group. Full relaxation of the aorta to acetylcholine was preserved., a2_It can be concluded that remarkable alterations in the cardiovascular system were found in offsprings of hypertensive NO compromised parents., M. Gerová, I. Bernátová, J. Török, M. Juráni., and Obsahuje bibliografii