Erythropoietin reduces collagen deposition after myocardial infarction but does not improve cardiac function

Abstract

Myocardial remodeling includes inappropriate collagen deposition in the interstitium. Erythropoietin (EPO) may have cardioprotective effects. We aimed to assess the role of EPO on myocardial remodeling during the chronic phase. We studied 60 Wistar rats divided into the following groups: control (CT), control + EPO (CT + EPO), myocardial infarction + EPO (MI + EPO), and myocardial infarction (MI). The interstitial collagen volume fraction (ICVF) was quantified and echocardiography was performed. We quantified asymmetric dimethylarginine and glutathione by ELISA, and used real-time PCR to assess apoptosis and inflammation. Western blotting was used to evaluate inflammatory proteins and tissue inhibitors of metalloproteinases (TIMPs), and TUNEL staining was used to detect apoptosis. For matrix metalloproteinases (MMPs), we performed zymography. Parametric and nonparametric analyses were performed according to normality testing. ICVF was greater in MI groups (p < 0.001) and was attenuated by EPO (p = 0.05). The MMP-2 did not show any difference between groups. The TIMP-1 and TIMP-2 did not have difference between groups. The MI groups had worse fraction shortening (p < 0.001), without EPO protection (p = 0.666). The MI groups had increased left ventricle diastolic dimension (p < 0.001) without EPO attenuation (p = 0.79). EPO did not act on oxidative stress. Apoptosis and inflammation were not modulated by EPO. We concluded that EPO attenuated interstitial collagen accumulation, but did not protect from heart dilation or dysfunction.