Objective

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a potent natural inhibitor of hematopoietic stem cell proliferation which is degraded mainly by angiotensin-converting enzyme (ACE). In vitro, Ac-SDKP inhibits collagen production by cardiac fibroblasts; while in vivo it blocks collagen deposition in the left ventricle (LV) of rats with hypertension or myocardial infarction (MI). In addition, it reportedly prevents and reverses macrophage infiltration in the LV of rats with MI. We tested the hypothesis that when Ac-SDKP is infused at doses that cause plasma concentrations similar to those observed after ACE inhibition, it mimics the anti-inflammatory and antifibrotic effects of ACE inhibitors (ACEi) in the heart, and, further, that these effects are independent of changes in blood pressure.