Decreased serum MMP-9/TIMP-1 ratio in patients with non-traumatic osteonecrosis of the femoral head after vascularized iliac bone grafting

Abstract

Abstract Background Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) are involved in the pathological mechanism of osteonecrosis of the femoral head (ONFH). This study aimed to investigate the relationship between serum MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio and disease severity in patients with nontraumatic ONFH. Methods An enzyme-linked immunosorbent assay (ELISA) was used to measure Serum levels of MMP-9 and TIMP-1 in 102 patients with ONFH and 96 healthy individuals and 16 FICAT stage 2 patients undergoing vascularized iliac grafting in the postoperative period (1 week ,1 month, 2 month, and 3 month) Results The serum MMP-9 levels and the MMP-9/TIMP-1 ratio were significantly increased in patients with ONFH compared to normal controls, and TIMP-1 levels did not differ between the two groups. Serum MMP-9 levels and MMP-9/TIMP-1 ratio were positively correlated with FICAT stage and VAS, and negatively correlated with HHS score. Compared with the preoperative period, patients with vascularized iliac grafting had lower VAS scores, higher HHS scores, and significantly lower serum MMP-9/TIMP-1 ratios.ROC curve analysis indicated that decreased serum MMP-9/TIMP-1 ratio could be a decent biomarker with regard to monitoring improved condition in patients with ONFH after vascularized iliac grafting. Conclusions We hypothesize that increased MMP-9 expression and imbalance in the MMP-9/TIMP-1 ratio play a role in the development of ONFH and correlate with the severity of ONFH. measurement of MMP-9 and MMP-9/TIMP-1 can be a useful tool in order to evaluate the bone remodelling processes after vascularized iliac grafting in patients with ONFH.