Modou Oumy Kane

Angiotensin II-Induced Hypertension Is Associated with a Selective Inhibition of Endothelium-Derived Hyperpolarizing Factor-Mediated Responses in the Rat Mesenteric Artery

Hypertension has been shown to be associated with impaired endothelium-derived hyperpolarizing factor (EDHF)-mediated arterial relaxation and hyperpolarization. Treatments of hypertensive rats with inhibitors of the renin-angiotensin system have been shown to restore both EDHF-mediated responses and the expression of connexins involved in the intercellular transfer of the hyperpolarization in mesenteric arteries. The present study was designed to determine whether chronic treatment of rats with angiotensin II impairs EDHF-mediated responses and the expression of connexins in the mesenteric arterial wall. Male Wistar rats were treated with angiotensin II (0.4 mg/kg/day) for 21 days using osmotic minipumps. Arterial pressure was measured by tail-cuff plethysmography. Contractile responses and membrane potential were measured in isolated mesenteric arteries. The expression of the three connexins (Cxs), Cx37, Cx40, and Cx43, was quantified in segments of mesenteric arteries by immunohistochemistry and quantitative real-time reverse transcriptase-polymerase chain reaction. Angiotensin II administration increased the mean systolic blood pressure. EDHF-mediated relaxation and hyperpolarization to acetylcholine and red wine polyphenols were significantly impaired in mesenteric arteries from angiotensin II-treated rats in comparison with control animals, whereas nitric oxide-mediated relaxation was unaltered. The expression of connexins Cx37, Cx40, and Cx43 was significantly decreased in the mesenteric artery from angiotensin II-treated rats. These findings indicate that angiotensin II-induced hypertension is associated with a selective impairment of EDHF-mediated relaxation and hyperpolarization in the rat mesenteric artery. The inhibition of EDHF-mediated responses is due, at least in part, to a decreased expression of connexins Cx37, Cx40, and Cx43 in the arterial wall.

Angiotensin II Induces the Vascular Expression of VEGF and MMP-2 in vivo: Preventive Effect of Red Wine Polyphenols

Objective: Previous investigations have indicated that angiotensin II (Ang II)-induced hypertension and endothelial dysfunction are prevented by intake of red wine polyphenols (RWPs). Ang II has also been shown to increase the expression of VEGF and MMP-2, two major pro-inflammatory factors, in vascular diseases. Therefore, the aim of the present study was to determine whether intake of RWPs is able to prevent these effects in rats and, if so, to characterize the underlying mechanism. Methods: VEGF and endothelial NO synthase (eNOS) expression was assessed by immunofluorescence and Western blotting, MMP-2 activity by zymography, and reactive oxygen species (ROS) formation by dihydroethidine. Results: Ang II increased VEGF expression and MMP-2 activity in the aortic wall. Ang II-induced MMP-2 activation is inhibited by NG-nitro-L-arginine and MnTMPyP. Ang II increased the expression of eNOS, the formation of ROS and the nitration of proteins. The stimulatory effects of Ang II on these factors are prevented by RWPs intake. Conclusions: Infusion of Ang II induced vascular expression of VEGF and peroxynitrite-dependent activation of MMP-2, with both effects being prevented by RWPs intake. Thus, prevention of VEGF and MMP-2 expression might be involved in the protective effect of red wine on coronary heart diseases.

In vitro vasorelaxation mechanisms of bioactive compounds extracted from Hibiscus sabdariffa on rat thoracic aorta

BackgroundIn this study, we suggested characterizing the vasodilator effects and the phytochemical characteristics of a plant with food usage also used in traditional treatment of arterial high blood pressure in Senegal.MethodsVascular effects of crude extract of dried and powdered calyces of Hibiscus sabdariffa were evaluated on isolated thoracic aorta of male Wistar rats on organ chambers. The crude extract was also enriched by liquid-liquid extraction. The various cyclohexane, dichloromethane, ethyl acetate, butanol extracts obtained as well as the residual marc were subjected to Sephadex LH-20 column chromatography. The different methanolic eluate fractions were then analyzed by Thin Layer (TLC) and High Performance Liquid Chromatography (HPLC) and their vascular effects also evaluated.ResultsThe H. Sabdariffa crude extract induced mainly endothelium-dependent relaxant effects. The endothelium-dependent relaxations result from NOS activation and those who not dependent to endothelium from activation of smooth muscle potassium channels. The phytochemical analysis revealed the presence of phenolic acids in the ethyl acetate extract and anthocyans in the butanolic extract. The biological efficiency of the various studied extracts, in term of vasorelaxant capacity, showed that: Butanol extract > Crude extract > Residual marc > Ethyl acetate extract. These results suggest that the strong activity of the butanolic extract is essentially due to the presence of anthocyans found in its fractions 43-67.ConclusionThese results demonstrate the vasodilator potential of hibiscus sabdariffa and contribute to his valuation as therapeutic alternative.

Dyslipidemia, obesity and other cardiovascular risk factors in the adult population in Senegal

Introduction According to the WHO, 50% of deaths worldwide (40.1% in developing countries) are due to chronic non-communicable diseases (NCDs). Of these chronic NCDs, cardiovascular diseases remain the leading cause of death and disability in developed countries. The Framingham study has shown the importance of hypercholesterolemia as a primary risk factor. In Senegal, the epidemiology of dyslipidemia and obesity are still poorly understood due to the lack of comprehensive studies on their impact on the general population. This motivated this study to look into the key epidemiologic and socio-demographic determinants of these risk factors. Methods It was a cross-sectional descriptive epidemiological survey which included 1037 individuals selected by cluster sampling. Data were collected using a questionnaire following the WHO STEPwise approach. Socio-demographic, health and biomedical variables were collected. P value <0.05 was considered to be statistically significant. Results The average age was 48 years with a female predominance (M: F of 0.6). The literacy rate was 65.2% and 44.7% of participants were from rural areas. The prevalence of hypercholesterolemia, hyperLDLemia, hypoHDLemia, hypertriglyceridemia and mixed hyperlipidemia were 56%, 22.5%, 12.4%, 7.11% and 1.9% respectively. One in four was obese (BMI> 30kg/m2) and 34.8% had abdominal obesity. The main factors significantly associated with dyslipidemia were obesity, urban dwelling, physical inactivity and a family history of dyslipidemia. Conclusion The prevalence of dyslipidemia, obesity and other risk factors in the population was high needing immediate care for those affected and implementation of prevention strategies.

[Evaluation of erythrocyte deformability in subjects with sickle cell trait during a soccer game: effect of hydration ad libitum].

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

Évaluation de la déformabilité érythrocytaire des sujets porteurs de trait drépanocytaire au cours d’un match de football : effet de l’hydratation ad libitum

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

Évaluation de la déformabilité érythrocytaire des sujets porteurs de trait drépanocytaire au cours d'un match de football : effet de l'hydratation ad libitum Evaluation of erythrocyte deformability in subjects with sickle cell trait during a soccer game: effect of hydration ad libitum

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.