Wine polyphenols improve cardiovascular remodeling and vascular function in NO-deficient hypertension

The effects of the red wine polyphenolic compounds (Provinol) on hypertension, left ventricular hypertrophy, myocardial fibrosis, and vascular remodeling were investigated after chronic inhibition of nitric oxide (NO) synthase by administration of N(G)-nitro-L-arginine methyl ester (L-NAME) to rats. Rats were divided into four groups: a control group, a group treated for 4 wk with L-NAME (40 mg x kg(-1) x day(-1)), and two groups treated with L-NAME followed by 3 wk of either spontaneous recovery or recovery with Provinol treatment (40 mg x kg(-1) x day(-1)). Administration of Provinol produced a greater readiness of the decrease in blood pressure than that in the spontaneous recovery group. Provinol significantly depressed myocardial fibrosis and expedited the decrease in aortic cross-sectional area, the increase in endothelium-dependent relaxation, and the decrease in contraction of the aorta. These effects of Provinol were associated with a greater increase of NO synthase activity in the left ventricle and the aorta. The present study provides evidence that Provinol accelerates the regression of blood pressure and improves structural and functional cardiovascular changes produced by chronic inhibition of NO synthesis.     

Sodium and ATP affinities of the cardiac (Na,K)-ATPase in relation to nitric oxide synthesis in spontaneously hypertensive rats

The (Na,K)-ATPase is hypothesized to be involved in systemic vascular hypertension through its effects on smooth muscle reactivity and cardiac contractility. Investigating the kinetic properties of the above enzyme we tried to assess the molecular basis of alterations in transmembraneous efflux of Na(+) from cardiac cells in spontaneously hypertensive rats (SHR) with increased synthesis of nitric oxide (NO). In the investigated group of SHR the systolic blood pressure was increased by 64% and the synthesis of NO was increased by 60% in the heart. When activating the cardiac (Na,K)-ATPase with substrate, its activity was higher in SHR in the whole concentration range of ATP. Evaluation of kinetic parameters revealed an increase of the V(max) (by 37%) probably due to increased affinity of the ATP-binding site as indicated by the lowered K(m) value (by 38%) in SHR. During activation with Na(+), we observed no change in the enzyme activity below 10 mmol/l of NaCl whereas in the presence of higher concentrations of NaCl the (Na,K)-ATPase was stimulated. The value of V(max) increased (by 64%), however the K(Na) increased (by 106%), indicating an adaptation of the Na(+)-binding site of the enzyme to increased [Na(+)](i). Thus the (Na,K)-ATPase in our SHR group is able to extrude the excessive Na(+) from myocardial cells more effectively also at higher [Na(+)](i), while the enzyme from controls is unable to increase its activity further. This improvement of the (Na,K)-ATPase function is supported also by increased affinity of its ATP-binding site probably due to enhanced NO-synthesis.     

Red wine polyphenols induce vasorelaxation by increased nitric oxide bioactivity

The aim of the present study was to investigate the mechanism of vasorelaxant responses induced by red wine polyphenolic compounds (Provinol). Rings of rat femoral artery with or without functional endothelium were set up in a myograph for isometric recording and precontracted with phenylephrine (10(-5) M). Provinol in cumulative doses (10(-9) to 10(-3) mg/ml) elicited endothelium- and dose-dependent relaxation of the artery with maximal relaxation of 56 per cent at the concentration of 10(-5) mg/ml. The relaxant responses to Provinol correlated well with the increase of NO synthase activity in the vascular tissue after administration of cumulative doses of Provinol (10(-9) to 10(-3) mg/ml). N(G)-nitro-L-arginine methylester (L-NAME, 3x10(-4) M) significantly attenuated the endothelium-dependent relaxation produced by Provinol. Administration of L-arginine (3x10(-5) M) restored the relaxation inhibited by L-NAME. The relaxant responses of Provinol were abolished in the presence of Ca(2+)-entry blocker, verapamil (10(-6) M). Administration of hydrogen peroxide (H(2)O(2)) abolished acetylcholine (10(-5) M)-induced relaxation of the rat femoral artery, while administration of Provinol (10(2) mg/ml) together with H(2)O(2) helped to maintain the acetylcholine-induced relaxation. Provinol only partially affected the concentration-response curve for the NO donor sodium nitroprusside-induced relaxation in rings without endothelium. In conclusion, Provinol elicited endothelium-dependent relaxation of rat femoral artery by the Ca(2+)-induced increase of NO synthase activity and by protecting NO from degradation.     

Vasodilatory activity in horsefly and deerfly salivary glands

Salivary gland extract (SGE) of four horsefly species (Hybomitra bimaculata Macquart, Hybomitra ciureai Séguy, Tabanus bromius L., Tabanus glaucopis Meigen) and one deerfly species (Chrysops relictus Meigen) (Diptera: Tabanidae) were shown to contain vasodilatory activity. Aliquots equivalent to 1, 5 and 10 pairs of salivary glands (SG) relaxed rat femoral artery (with intact endothelium) pre-constricted with phenylephrine. Vasodilatory activity was dose-dependent. SGE of one horsefly species (Haematopota pluvialis L.) did not induce relaxation. The kinetics of vasodilation induced by SGE of four horsefly species differed from the deerfly. These results indicate that tabanid species may produce more than one type of vasodilator to aid blood feeding.     

Effect of captopril on cyclic nucleotide concentrations during long-term NO synthase inhibition

The aim of the present study was to determine the effect of angiotensin-converting enzyme inhibitor captopril on cGMP and cAMP concentration in the left ventricle and aorta after NO synthase inhibition by 4-week-lasting N(G)-nitro-L-arginine-methyl ester (L-NAME) treatment. Five groups of rats were investigated: controls, L-NAME in the dose 20 mg/kg/day (L-NAME 20), L-NAME in the dose 40 mg/kg/day (L-NAME 40), captopril in the dose 100 mg/kg/day, L-NAME 40 mg/kg/day together with captopril 100 mg/kg/day. Captopril completely prevented L-NAME-induced hypertension and LV hypertrophy development. Compared to the controls, cGMP concentration in the L-NAME 20 and L-NAME 40 groups was decreased by 13% and 22%, respectively, in the left ventricle and by 27% and 56% in the aorta, respectively. Captopril did not influence this decrease of cGMP concentration. Cyclic AMP concentration in the aorta of L-NAME 20 group increased by 17%. In the L-NAME 40 group, cAMP concentration increased by 17% in the left ventricle and by 34% in the aorta compared to controls. This increase was enhanced in rats given L-NAME together with captopril. Captopril alone had no effect on cAMP concentration. We conclude that captopril does not affect the concentration of cGMP, however, it has more than the additive effect on the cAMP concentration increase in the cardiovascular system during long-term NO synthase inhibition.     

B30.2-like domain proteins: update and new insights into a rapidly expanding family of proteins

The B30.2 domain is a conserved region of around 170 amino acids associated with several different protein domains, including the immunoglobulin folds of butyrophilin and the RING finger domain of ret finger protein. We recently reported several novel members of this family as well as previously undescribed protein families possessing the B30.2 domain. Many proteins have subsequently been found to possess this domain, including pyrin/marenostrin and the midline 1 (MID1) protein. Mutations in the B30.2 domain of pyrin/marenostrin are implicated in familial Mediterranean fever, and partial loss of the B30.2 domain of MID1 is responsible for Opitz G/BBB syndrome, characterized by developmental midline defects. In this study, we scrutinized the available sequence data bases for the identification of novel B30.2 domain proteins using highly sensitive database-searching tools. In addition, we discuss the chromosomal localization of genes in the B30.2 family, since the encoded proteins are likely to be involved in other forms of periodic fever, autoimmune, and genetic diseases.      

Out of Africa and back again: nested cladistic analysis of human Y chromosome variation

We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of approximately 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.      

A PCR-based method for diet analysis in freshwater organisms using 18S rDNA barcoding on faeces

The development of DNA barcoding from faeces represents a promising method for animal diet analysis. However, current studies mainly rely on prior knowledge of prey diversity for a specific predator rather than on a range of its potential prey species. Considering that the feeding behaviour of teleosts may evolve with their environment, it could prove difficult to establish an exhaustive listing of their prey. In this article, we extend the DNA barcoding approach to diet analysis to allow the inclusion of a wide taxonomic range of potential prey items. Thirty-four ecological clade-specific primer sets were designed to cover a large proportion of prey species found in European river ecosystems. Selected primers sets were tested on isolated animal, algal or plant tissues and thereafter on fish faeces using nested PCR to increase DNA detection sensitivity. The PCR products were sequenced and analysed to confirm the identity of the taxa and to validate the method. The methodology developed here was applied to a diet analysis of three freshwater cyprinid species that are assumed to have similar feeding behaviour [Chondrostoma toxostoma toxostoma (Vallot 1837), Chondrostoma nasus nasus (Linnaeus, 1758) and Barbus barbus, (Linneaus 1758)]. These three species were sampled in four different hydrographic basins. Principal Component Analysis based on prey proportions identified distinct perilithon grazer and benthophagous behaviours. Furthermore, our results were consistent with the available literature on feeding behaviour in these fish. The simplicity of the PCR-based method and its potential generalization to other freshwater organisms may open new perspectives in food web ecology.     

Chronic and acute effects of different antihypertensive drugs on femoral artery relaxation of L-NAME hypertensive rats

We aimed to compare the effects of chronic and acute administration of structurally different antihypertensives, diuretics - indapamide and hydrochlorothiazide, ACE inhibitor - captopril and indapamide+captopril combination on endothelium-dependent relaxation of femoral artery isolated from nitric oxide (NO)-deficient rats. In the chronic experiment, femoral artery was isolated from Wistar rats receiving L-NAME (40 mg/kg/day) solely or with indapamide (1 mg/kg/day), hydrochlorothiazide (10 mg/kg/day), captopril (10 mg/kg/day), and indapamide+captopril combination for seven weeks. In the acute in vitro experiment, the incubation medium with femoral artery isolated from L-NAME-hypertensive rats was supplemented with investigated antihypertensives in the same concentration 10(-4) mol/l. Interestingly, chronic L-NAME treatment did not cause a reduction of vasorelaxation. Indapamide+captopril elevated relaxation above the control level and completely prevented blood pressure increase induced by L-NAME. Acute incubation with captopril only or indapamide+captopril improved relaxation of femoral artery isolated from L-NAME-hypertensive rats, while the incubation with all antihypertensives increased vasorelaxation of femoral artery isolated from control Wistar rats. In conclusion, NO might be involved in the indapamide- and hydrochlorothiazide-induced improvement of vasorelaxation, while different vasorelaxing factors (prostacyclin, EDHF) contribute to the captopril-induced improvement of vasorelaxation. During the chronic treatment additive and synergic effects of indapamide and captopril may contribute to the prevention of hypertension and increase of vasorelaxation.     

Morphological alterations and NO-synthase expression in the heart after continuous light exposure of rats

Although exposure to continuous light is associated with hypertension and modulates the outcome of ischemia-reperfusion injury, less attention has been paid to its effects on cardiac morphology. We investigated whether 4-week exposure of experimental rats to continuous 24 h/day light can modify cardiac morphology, with focus on heart weight, fibrosis and collagen I/III ratio in correlation with NO-synthase expression. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light. After 4 weeks of treatment the absolute and the relative heart weights were determined and myocardial fibrosis and collagen type I/III ratio were evaluated using picrosirius red staining. Endothelial and inducible NO-synthase expression was detected immunohistochemically. The exposure of rats to continuous light resulted in an increase of body weight with proportionally increased heart weight. Myocardial fibrosis remained unaffected but collagen I/III ratio increased. Neither endothelial nor inducible NO-synthase expression was altered in light-exposed rats. We conclude that the loss of structural homogeneity of the myocardium in favor of collagen type I might increase myocardial stiffness and contribute to functional alterations after continuous light exposure.