HTRA1 and obesity due to melanocortin 4 receptor deficiency: The levels of HTRA1, a negative regulator of mesenchymal stem cell (MSC) adipogenesis, and matrix metalloproteinase-13 (MMP-13) proteins, which played an important role in the pathophysiology of adipose tissue, were evidently high in the visceral adipose tissue of IR obese patients and also in the cardiac tissue of DCM patients [38,39,40], lending support to HTRA1 mediating the potential pathogenesis of DCM and obesity.