Efeitos de peptídeos ricos em prolina do veneno da serpente Bothrops Jararaca sobre a revascularização de membros posteriores isquêmicos de camundongos normoglicêmicos e hiperglicêmicos

Abstract

Therapeutic angiogenesis has been proposed as an alternative for the treatment of ischemic diseases, such as Peripheral Artery Disease. Inhibitors of angiotensin converting enzyme (ACEi), in addition to their antihypertensive properties, are also capable of increasing ischemia-induced angiogenesis. ACEi have been developed based on the first prolin-rich oligopeptides of Bothrops jararaca venom (Bj-PROs) previously known as bradykinin potentiating peptides (BPPs). However, the antihypertensive effects of novel Bj-PROs, among them Bj-PRO-5a, Bj-PRO-7a and Bj-PRO-10c, are not related to their ability to inhibit ACE. Therefore, our aim was to evaluate whether these new peptides (71 nmol / kg, i.p., every 24 hours) would affect ischemic hindlimb revascularization (femoral artery occlusion model - FAO) of normoglycemic and/or hyperglycemic animals (Type I diabetes - DM1 - induced by streptozotocin - STZ). We observed beneficial effects of the Bj-PRO-5a peptide on ischemic limbs blood flow recovery and increased capillary and arteriolar densities as well as VEGF levels in the ischemic muscles of normoglycemic animals. In addition, this peptide stimulated the mobilization of circulating angiogenic cells (CACs) from the bone marrow. Interestingly, all of these effects were abolished in mice knockouts for the Bradykinin B1 receptor (B1R-KO), but not in B2R-KO animals or wildtype (WT) animals treated with L-NAME. However, we did not observe improvement in the blood flow recovery of ischemic hindlimbs in STZ-induced diabetic animals treated with the peptide Bj-PRO-5a. Of note, our group has previously demonstrated that peptides Bj-PRO-7a and Bj-PRO-10c stimulate revascularization of ischemic hindlimbs of normoglycemic animals. Here, we then evaluated the effects of these peptides on the revascularization of ischemic hindlimbs of animals with STZ-induced DM1. Our results demonstrate an improvement in blood flow recovery and a significant increase in angiogenesis and arteriogenesis. In addition, Bj-PRO-7a, but not BjPRO-10c, stimulated the mobilization of CACs into the blood. Interestingly, although none of these peptides altered the glucose intolerance of the DM1 group, the peptide Bj-PRO-7a, but not Bj-PRO-10c, presented a hypoglycemic effect. In conclusion, our data suggest that the Bj-PRO5a peptide enhances the revascularization of ischemic hindlimbs from normoglycemic mice, but not from those with DM1. These effects seem to involve the activity of the kinin B1R receptor and are partially dependent on the release of nitric oxide, but are independent of B2R receptor activity. In addition, the peptides Bj-PRO-7a and Bj-PRO-10c are capable of stimulating revascularization of ischemic hindlimbs in mice with DM1.