IGFBP5 affects cardiomyocyte survival and functional recovery in mice following myocardial ischemia.

Insulin-like growth factor-binding protein 5 (IGFBP5) has been shown to be useful for the diagnosis and treatment of multiple tumors and cerebrovascular diseases. However, it is unknown whether IGFBP5 is involved in myocardial repair following myocardial infarction (MI). Here we show high expression of IGFBP5 in multiple models of ischemic and hypoxic injury. IGFBP5 affected the proliferation of neonatal rat cardiomyocytes (NRCMs) and the cardiomyocyte apoptosis induced by oxygen-glucose deprivation (OGD). Subsequently, heart-specific IGFBP5 knockdown inhibited myocardial apoptosis and increased cardiomyocyte proliferation in mice with MI. During the chronic remodeling stage, heart-specific regulation of IGFBP5 ameliorated pathological cardiac remodeling and dysfunction. Mechanistically, IGFBP5 regulated cardiomyocyte survival through the insulin-like growth factor 1 (IGF1) receptor (IGF1R)/protein kinase B (PKB/AKT) pathway. In summary, our results provide mechanistic insights into the effect of IGFBP5 on cardiomyocyte during cardiac repair. IGFBP5 may represent a therapeutic target for myocardial ischemic injury.