COL1A1 and renal fibrosis: Further, rats that were fed the HP-HCa2+ diet expressed lower levels of four key markers (Kronenberg, 2009) of renal damage and fibrosis (NGAL, COL1A1, COL6A2, and MPG) (Figure 5—figure supplement 4A) and exhibited decreased renal fibrosis revealed by Masson’s trichrome staining to detect collagen (Figure 5M, Figure 5—figure supplement 4B–C).