APOE and obesity due to melanocortin 4 receptor deficiency: The present study investigated the MMP-12 function in obesity-induced glomerular fibrogenesis and inflammation in mice lacking apolipoprotein E alone (apo E−/−)—which are predisposed to obesity—or both apo E and MMP-12 (apo E−/−MMP-12−/−) that were maintained on HFD for 3, 6, or 9 months.