Fig 1: Vit D supplementation slows down KC progression by inhibiting collagen degradation systemically. (A) Plasma collagen degradation markers measured by ELISA: ICTP, MMP-9, (MMP-1, TIMP-1, and IL-1ß. Results are expressed as fold change between month 0 and month 6 (M6/M0). (B) To establish the degradation status, we calculated the ratio between MMP-9 and TIMP-1 at months 0 and 6. (C, D) The MMP-9/TIMP-1 ratio inversely correlated with Vit D levels (C) and VDR expression (D) measured by RT-PCR. M0, n = 20 patients; M6, n = 20 patients. Graphs represent the mean ± SD. Statistical analysis was performed using the one-sample t-test, Wilcoxon signed-rank test, or Spearman's correlation coefficient. *P < 0.05, **P < 0.01, ***P < 0.001.
Fig 2: Vit D arrests KC progression. The increased availability of active Vit D results in the downregulation of MMP-9 levels while increasing TIMP-1 systemically. This, in turn, inhibits collagen degradation, supported by the lower levels of collagen degradation products (ICTP) observed. Additionally, Vit D halts KC progression by improving Cu availability, which would result in increased endogenous collagen CXL by LOX and antioxidant capacity by SOD.
Supplier Page from Wuhan Fine Biotech Co., Ltd. for Human MMP-9(Matrix Metalloproteinase 9) ELISA Kit