Relationships between MMP-2, MMP-9, TIMP-1 and TIMP-2 levels and their pathogenesis in patients with lupus nephritis.

Recent evidence suggests that matrix metalloproteinases (MMPs) were involved with many kinds of kidney diseases. We investigated the roles of MMPs and its tissue inhibitors TIMPs in patients with lupus nephritis (LN). A total of 44 systemic lupus erythematosus patients and 31 healthy subjects were enrolled. The levels of total MMP-2, 9 (tMMP-2, tMMP-9) along with TIMP-1, 2 were measured in serum by ELISA. Serum tMMP-2, tMMP-9 was higher in LN patients than those non-LN patients and healthy controls. Serum tMMP-2 in patients without LN was higher than in healthy controls. TIMP-2 was higher in LN patients than healthy controls, and no significant difference in TIMP-2 was observed between LN and non-LN patients. TIMP-1 levels among LN, non-LN patients and healthy controls were comparable. The ratio of tMMP-9 to TIMP-1 in LN patients was higher than non-LN patients and healthy controls and no difference in ratio of tMMP-9 to TIMP-1 between non-LN patients and healthy subjects was observed. A negative correlation between the ratio of tMMP-9 to TIMP-1 in lupus patients and the titers of anti-dsDNA was found; whereas, no correlation between the ratio of tMMP-9 to TIMP-1 and the concentration of C3 as well 24 h urine protein was observed in LN patients. We suggest imbalance between tMMP-9 and TIMP-1 may contribute to the pathogenesis of LN. Measurement of MMPs and TIMPs may be helpful in the early identification of lupus patients with LN and may help gauge the response to treatment in patients with active LN undergoing treatment.