Bradicinina restaura a função ventricular de cães com distrofia muscular
França – a bradicinina é uma substância endógena com atividade sobre o endotélio dos vasos e sobre as células cardíacas, tendo sido descoberta por um brasileiro. A injeção da bradicinina em cães promoveu uma significativa melhora das alterações cardiovasculares observadas nestes animais.
O texto em inglês pode ser lido abaixo:
(Cardiovasc Res, May 2012) Bradykinin restores left ventricular function, sarcomeric protein phosphorylation and e/nNOs levels in dogs with Duchenne muscular dystrophy cardiomyopathy
Jin Bo Su, Olivier Cazorla, Stéphane Blot, Nicolas Blanchard-Gutton, Younss Ait Mou, Inès Barthélémy, Lucien Sambin, Carolina Carlos Sampedrano, Vassiliki Gouni, Yves Unterfinger, Pablo Aguilar, Jean-Laurent Thibaud, Alain Bizé, Jean-Louis Pouchelon, Hubert Dabiré, Bijan Ghaleh, Alain Berdeaux, Valérie Chetboul, Alain Lacampagne, and Luc Hittinger – France
Aims Cardiomyopathy is a lethal result of Duchenne muscular dystrophy (DMD) but its characteristics remain elusive. The golden retriever muscular dystrophy (GRMD) dogs produce DMD pathology and mirror DMD patient’s symptoms including cardiomyopathy. We previously showed that bradykinin slows the development of pacing-induced heart failure. Therefore, the goals of this research were to characterize dystrophin-deficiency cardiomyopathy and to examine cardiac effects of bradykinin in GRMD dogs
Methods and results At baseline, adult GRMD dogs had reduced fractional shortening (28±2% vs 38±2% in control dogs, p<0.001) and left ventricular (LV) subendocardial dysfunction leading to impaired endo-epicardial gradient of radial systolic velocity (1.3±0.1 cm/s vs 3.8±0.2 cm/s in control dogs, p<0.001) measured by echocardiography. These changes were normalized by bradykinin infusion (1 µg/min, 4 weeks). In isolated permeabilized LV subendocardial cells of GRMD dogs, tension-calcium relationships were shifted downward and force-generating capacity and transmural gradient of myofilament length-dependent activation were impaired compared with control dogs. Concomitantly, phosphorylation of sarcomeric regulatory proteins and levels of endothelial and neuronal nitric oxide synthase in LV myocardium were significantly altered in GRMD dogs. All these abnormalities were normalized in bradykinin-treated GRMD dogs
Conclusions Cardiomyopathy in GRMD dogs is characterized by profound LV subendocardial dysfunction, abnormal sarcomeric protein phosphorylation and impaired endothelial and neuronal nitric oxide synthase, which can be normalized by bradykinin treatment. These data provide new insights into pathophysiological mechanisms accounting for DMD cardiomyopathy and open new therapeutic perspectives.
