Introduction: Peripheral vascular disease is a major risk factor for lower-extremity amputation in patients with diabetes due to an abnormal angiogenic response. The apelinergic system is known to improve cardiac function after ischemia by promoting angiogenesis.

The objective: is to study the effects of Apelin-13 (Ape-13) and Elabela (Ela) on blood flow (BF) reperfusion following limb ischemia in diabetic mice as well as on endothelial cell (EC) function.

Method: Primary EC were exposed to normal (5.6 mM; NG) or high (25 mM; HG) glucose concentrations for 24h and hypoxia (1% O2) for the last 16h. EC were stimulated or not with Ape-13 or Ela. Proliferation and migration assays were performed and apelin signaling pathway was evaluated by immunoblot and qPCR. In vivo, nondiabetic (NDM) and diabetic (DM) underwent femoral artery ligation to induce lower limb ischemia. DM mice received Ape-13 or Ela by subcutaneous osmotic pump. BF reperfusion was measured for 4 weeks post-surgery and exercise willingness was assessed in individual cages with voluntary wheel. The ischemic abductor muscles were collected for protein, genes and vascular density analyses.

Results: Inhibitory effects of HG exposure on EC migration and proliferation were prevented with Ape-13 and Ela treatment under hypoxia condition through activation of Akt, AMPK and Rock2. In vivo, our results indicated that BF reperfusion was recovered at 75% in NDM as compared to 37% in DM whereas Ape-13 and Ela treatment in DM mice improved BF reperfusion by 65% and 69%, respectively. Similar results were observed using voluntary wheel as Ape-13 and Ela enhanced distance run as compared to untreated DM mice. Finally, the expression of proangiogenic factors (VEGF-A, PDGF-B) was increased in the ischemic muscle of DM+Ape-13 or Ela as compared to DM mice.

Conclusion: We believe that stimulation of apelinergic system improved BF recovery in DM by increasing proangiogenic pathways and EC migration and proliferation.

Disclosure

S. Robillard: None. P. Geraldes: None.

Funding

Canadian Institutes of Health Research (PJT159627)

© 2021 by the American Diabetes Association
2021
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