Blood pressure lowering effect of (-)-epicatechin diet in L-NAME induced hypertension

M. GALLEANO; M. C. LITERIO; G. SAGDICOGLU CELEP; G. JAGGERS; Y. OMATA; C. G. FRAGA

Santiago, Chile

Congreso; VI Meeting of Society for Free Radical Biology and Medicine South American Group; 2009

Society for Free Radical Biology and Medicine South American Group

Blood pressure lowering effect of (-)-epicatechin diet in L-NAME induced hypertension M. Galleano1, C. Litterio1, G. Sagdicoglu Celep2, G. Jaggers3, Y. Omata3, and C.G. Fraga1,3. 1University of Buenos Aires-CONICET, Buenos Aires, Argentina; 2Gazi University, Ankara , Turkey; 3University of California, Davis, USA. mgallean@ffyb.uba.ar Hypertension is a highly prevalent cardiovascular risk factor. Lifestyle modifications, including diet,  have been proposed as strategies to reduce blood pressure (BP) in hypertensive patients. This work has focussed on the modulatory effect of dietary (-)-epicatechin (EC) supplementation on BP. We use a rat model of L-NAME-induced hypertension. L-NAME was administered in drinking water (360 mg/l) and EC was co-administered added to the solid diet (1 mg/g diet –EC1- or  4 mg/g diet –EC4-). Male Sprague-Dawley rats (150 g) were divided into 4 groups: Control (C); L-NAME (L); L-NAME + EC 1 (LEC1); and L-NAME + EC 4 (LEC4) and maintained under treatments for 4 days. BP was measured by tail-cuff plethismography daily. At the fifth day animals were sacrificed and blood plasma was obtained to determine Nù-nitroarginine content, (-)-epicatechin levels, and oxidative and nitrosative stress parameters. Final BP (in mm Hg) were: C= 102±3; L= 143±6*; LEC1= 128±6# and LEC4= 110±8# (*p<0.05 respect to C; #p<0.05 respect to L). Plasma Nù-nitroarginine content increased in all the L-NAME treated groups and its level was not affected by EC supplementation. The decrease in BP was associated with the improvement in markers of  oxidative stress (plasma MDA and GSSG) and NO production related parameters (plasma nitrates+nitrites and protein bound nitrotyrosines). Those results would suggest that a an increase in NO bioavailability  as a consequence of diminished oxidant production should be a posiible mechanism involved in the BP lowering action of EC in this model. This work was supported by NIH AT2966 (USA); UCDavis CHNR (State of California Vitamin Price Fixing Consumer Settlement fund); and UBACyT B801 and B802). MG and CGF are members of the CIC, CONICET, Argentina.