Neonatal exposure to hyperoxia alters lung development in mice. We tested if retinoic acid (RA) treatment is capable to affect lung development after hyperoxic injury and to maintain structural integrity of lung. The gene of vascular endothelial growth factor A (VEGF-A) is one of the RA-responsive genes. Newborn BALB/c mice were exposed to room air, 40 % or 80 % hyperoxia for 7 days. One half of animals in each group received 500 mg/kg retinoic acid from day 3 to day 7 of the experiment. At the end of experiment we assessed body weight (BW), lung wet weight (LW), the wet-to-dry lung weight ratio (W/D) and the expression of mRNA for VEGF-A and G3PDH genes. On day 7 the hyperoxia-exposed sham-treated mice (group 80) weighed 20 % less than the room air-exposed group, whereas the 80 % hyperoxic group treated with RA weighed only 13 % less than the normoxic group. W/D values in 80 and 80A groups did not differ, although they both differed from the control group and from 40 groups. There was a significant difference between 40 and 40A groups, but the control group was different from 40 group but not from 40A groups. The 80 and 80A groups had mRNA VEGF-A expression lowered to 64 % and 41 % of the control group. RA treatment of normoxic and mild hyperoxic groups increased mRNA VEGF-A expression by about 50 %. We conclude that the retinoic acid treatment of newborn BALB/c mice exposed for 7 days to 80 % hyperoxia reduced the growth retardation in the 80 % hyperoxic group, reduced the W/D ratio in the 40 % but not in the 80 % hyperoxic group. Higher VEGF-A mRNA expression in the 80 % hyperoxic group treated with RA was not significant compared to the 80 % hyperoxic group., M. Zimová-Herknerová, J. Mysliveček, P. Potměšil., and Obsahuje bibliografii a bibliografické odkazy
The concept of vena contracta space reduction in tricuspid valve position was tested in an animal model. Feasibility of specific artificial obturator body (REMOT) fixed to the right ventricular apex and interacting with tricuspid valve leaflets was evaluated in three different animal studies. Catheter-based technique was used in three series of experiment in 7 sheep. First acute study was designed for evaluation if the screwing mode of guide wire anchoring to the right ventricular apex is feasible for the whole REMOT body fixing. Longer study was aimed to evaluate stability of the REMOT body in desired position when fixing the screwing wire on its both ends (to the right ventricular apex and to the skin in the neck area). X-ray methods and various morphological methods were used. The third acute study was intended to the REMOT body deployment without any fixing wire. In all of 7 sheep the REMOT was successfully inserted into the right heart cavities and then fixed to the ri ght ventricular apex area. When the REMOT was left in situ more than 6 months it was stable, induced adhesion to the tricuspid valve leaflet and was associated with a specific cell invasion. Releasing of the REMOT from the guiding tools was also successfully verified. Deployment of the obturator body in the aim to reduce the tricuspid valve orifice is feasible and well tolerated in the short and longer term animal model. Specific cell colonization including neovascularization of the obturator body was observed., J. Sochman ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The Prague Hereditary Hypercholesterolemic (PHHC) rat is a model of hypercholesterolemia. In previous experiments, it was found to be completely resistant to the development of atherosclerosis. It was assumed that the reverse transport of cholesterol (RCT) might be the reason for this resistance. In this study, RCT was measured in vivo by cholesterol efflux from macrophages to plasma, using previously established methods for RCT in mice (Rader 2003), optimized for measurements in rats. Primary cell culture of macrophages was labeled with 14Ccholesterol and then injected intraperitoneally into rats. Plasma and feces were collected at 24 and 48 h. The plasma 14Ccholesterol levels at both 24 and 48 h were significantly higher in male PHHC rats compared to control Wistar rats. The PHHC rats excreted less 14C-cholesterol in feces in 24 and 48 h compared to Wistar rats. The largest pool of 14C-cholesterol was found in the adipose tissue of PHHC rats and in contrast lower levels of 14Ccholesterol were measured in the liver and muscle tissues of PHHC rats compared with Wistar rats. Increasing release of 14Ccholesterol efflux from macrophages demonstrates accelerated RTC and leads to prevention of atherogenesis in PHHC rats., M. Schmiedtova, M. Heczkova, J. Kovar, I. Kralova Lesna, R. Poledne., and Obsahuje bibliografii
The vessels on the fetal side of the placenta differ from most other vascular beds except the lungs in that they respond to acute hypoxia by vasoconstriction. An essential role of calcium influx in the mechanism of this hypoxic fetoplacental vasoconstriction (HFPV) has been shown previously. That finding does not, however, exclude the possible involvement of other mechanisms of vascular tone regulation. In this study we tested the hypothesis that Rho-kinase-mediated calcium sensitization is involved in HFPV. We used a model of isolated rat placenta dually perfused (from both the maternal and fetal side) with Krebs salt solution saturated with normoxic and hypoxic gas mixture respectively at constant flow rate. Rho-kinase pathway was inhibited by fasudil (10 μM). We found that fasudil reduced basal normoxic fetoplacental vascular resistance and completely prevented HFPV. This suggests that the activity of Rho-kinase signaling pathway is essential for HFPV., P. Kafka, ... [et al.]., and Obsahuje seznam literatury
This study investigated the effects of riboflavin on energy metabolism in hypoxic mice. Kunming mice were fed diets containing riboflavin at doses of 6, 12, 24 and 48 mg/kg, respectively for 2 weeks before exposure to a simulated altitude of 6000 m for 8 h. Changes of riboflavin status and energy metabolism were assessed biochemically. Simultaneously, a 1H nuclear magnetic resonance (NMR) based metabolomic technique was used to track the changes of plasma metabolic profiling. It was found that the content of hepatic riboflavin was decreased and erythrocyte glutathione activation coefficient was elevated significantly under hypoxic condition. Meanwhile, increased plasma pyruvate, lactate, β-hydroxybutyrate and urea, as well as decreased plasma carnitine were observed. Riboflavin supplementation improved riboflavin status remarkably in hypoxic mice and decreased plasma levels of pyruvate, free fatty acids and β-hydroxybutyrate significantly. Plasma carnitine was increased in response to riboflavin supplementation. Results obtained from 1H NMR analysis were basically in line with the data from biochemical assays and remarkable changes in plasma taurine, choline and some other metabolites were also indicated. It was concluded that riboflavin requirement was increased under acute hypoxic condition and riboflavin supplementation was effective in improving energy metabolism in hypoxic mice., Y. P. Wang, J. Y. Wei, J. J. Yang, W. N. Gao, J. Q. Wu, C. J. Guo., and Obsahuje bibliografii
Airway smooth muscle (ASM) me mbrane depolarization through KCl opens L-type voltage dependent Ca 2+ channels (Ca v 1.2); its opening was considered the caus e of KCl contraction. This substance is used to bypass intracellular second messenger pathways. It is now clear that KCl also activates RhoA/Rho kinase (ROCK) pathway. ROCK isoforms are characterized as ROCK1 and ROCK2. Because ROCK1 seems the most abundant isotype in lung, we studied its participation in KCl stimulated bovine ASM. With methyl- β -cyclodextrin (M β CD) we disrupted caveolae, a membrane compartment considered as the RhoA/ROCK assembly site, and found that KCl contraction was reduced to the same extent (~26 %) as Y-27632 (ROCK inhibitor) treated tissues. We confirmed that KCl induces ROCK activation and this effect was annulled by Y-27632 or M β CD. In isolated plasmalemma, ROCK1 was localized in non-caveolar membrane fractions in Western blots from control tissues, but it transferred to caveolae in samples from tissues stimulated with KCl. Ca v 1.2 was found at the non-caveolar membrane fractions in control and M β CD treated tissues. In M β CD treated tissues stimulated with KCl, contraction was abolished by nifedipine; only the response to Ca v 1.2 opening remained as the ROCK component disappeared. Our result s show that, in ASM, the KCl contraction involves the translocation of ROCK1 from non- caveolar to caveolar regions an d that the proper physiological response depends on this translocation., B. Sommer ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Central administration of losartan effectively blocked the increase of blood pressure and drinking response induced by angiotensin II (Ang II) or carbachol. However, the relationship between angiotensin AT1 receptors and the natriuresis induced by brain cholinergic stimuli is still not clear. The purpose of the study is to reveal the role of brain angiotensin AT1 receptor in the carbachol-induced natriuresis and expression of neuronal nitric oxide synthase (nNOS) in the locus coeruleus (LC) and proximal co nvoluted tubule (PCT). Our results indicated that 40 min after in tracerebroventricular (ICV) injection of carbachol (0.5 μg), urinary sodium excretion was significantly increased to 0.548±0.049 μmol·min-1·100 g-1. Immunohistochemistry showed that carbachol induced an increase of neuronal nitric oxide synthase immunoreactivity (nNOS-IR) in the LC and renal proximal tubular cells. After pretreatment with losartan (20 μg), carbachol-induced urinary sodium excretion was reduced to 0.249±0.067 μmol·min-1·100 g-1. The same was true for carbachol-induced increase of nNOS-IR in the LC and PCT. The present data suggest that ICV cholinergic stimulation could induce a natriuresis and upregulate the activity of nNOS in the LC and PCT. The blockade of AT1 receptors might downregulate the effects induced by carbachol in the LC and PCT. Consequently, we provide a new evidence that brain angiotensinergic pathway and NO-dependent neural pathway contribute to the natriuresis following brain cholinergic stimulation and thus play an important role in the regulation of fluid homeostasis. Furthermore, the final effect of nitric oxide on proximal tubular sodium reabsorption participated in the natriuresis induced by brain cholinergic stimulation., M. Wang, C. L. Jiang, C. Y. Wang, Q. Y. Yao., and Obsahuje bibliografii a bibliografické odkazy
The pathogenesis of arterial hypertension in autosomal dominant polycystic kidney disease (ADPKD) is complex and likely dependent on interaction of hemodynamic, endocrine and neurogenic factors. We decided to evaluate the role of endothelin (ET1) and nitric oxide (NO) in the regulation of arterial blood pressure (BP) and to determine plasma levels of ET1 and NO in the group of patients with ADPKD. The ADPKD group (18 patients, 6 men + 12 women, mean age 44.611.7 years, with creatinine clearancecorrig > 1.1 ml/s) was compared with a control group of 27 healthy volunteers of comparable age. Plasma levels of ET1 assessed by direct RIA determination in the group of ADPKD patients (11.03±1.8 fmol/ml) were significantly increased (p<0.001) in comparison with the control group (2.660.58 fmol/ml), while no significant differences were observed between normotensive and hypertensive patients in the ADPKD group. Serum levels of NO were evaluated according to the determination of serum levels of their metabolites - nitrites/nitrates. Serum levels of NO in the group of ADPKD patients (39.85±6.38 μmol/l) were significantly higher (p<0.05) in comparison with the control group (22.7±1.20 μmol/l), whereas in the ADPKD group no significant differences were observed between normotensive and hypertensive patients. Thus, our study supports the concept of complex alteration of both vasoconstrictor and vasodilator systems in the pathogenesis of arterial hypertension in ADPKD., M. Merta, J. Reiterová, R. Ryšavá, V. Tesař, M. Jáchymová., and Obsahuje bibliografii
A short review on the role of endothelium and nitric oxide (NO) in experimental hypertension is presented in the light of the literature and our own recent findings. Based on these data, it is concluded that even though there is a lot of evidence in favor of the primary and causal association of endothelial dysfunction and NO in experimental hypertension, it seems still more plausible that they are causative in some types of hypertension only. Our own experience rather speaks for a secondary but still an important participation of endothelium in the maintenance and further elevation of high blood pressure. Endothelium plays a key role in the development of organ damages in hypertension., H. Vapaatalo, E. Mervaala, M.-L. Nurminen., and Obsahuje bibliografii
The prevalence of obesity is increasing worldwide at an alarming rate in both developed and developing countries. Obesity is a chronic complex disease of multifactorial origin resulting from a long-term positive energy balance, in which both genetic and environmental factors are involved. Genetically prone individuals are the first to accumulate fat in the present obesogenic environment. Obesity increases the risks of type 2 diabetes, hypertension, cardiovascular disease, dyslipidemia, arthritis, and several cancers and reduces the average life expectancy. Implementation of effective strategies in prevention and management of obesity should be come an important target in health care systems. Weight changes throughout life depend on the interaction of behavioral, genetic and environmental factors. Weight loss in response to weight management shows a wide range of interindividual variation which is largely influenced by genetic determinants. The strong control of weight loss by genotype was confirmed by twin and family studies. Recently, special attention has been paid to nutritional, hormonal, psychobehavioral and genetic factors which can predict the response to weight reduction programme. In this article currently available data on the role of obesity candidate gene polymorphisms in weight loss and maintenance are reviewed. It is believed that an elucidation of the genetic component in the prognosis of weight management could assist in the development of more effective and individually tailored therapeutic strategies., V. Hainer, H. Zamrazilová, J. Spálová, I. Hainerová, M. Kunešová, B. Aldhoon, B. Bendlová., and Obsahuje bibliografii a bibliografické odkazy