APOE and glomerular disorder: MMP-12 mRNA level increased with time; expression was absent in apo E−/−MMP-12−/− and only weakly detected in apo E−/− mice fed normal chow; however, the expression levels increased markedly 3, 6, and 9 months after apo E−/− mice were switched to HFD, suggesting that MMP-12 expression is induced over the course of glomerular disease progression by consumption of HFD (Fig. 3C).