Association Between Matrix Metalloproteinase-3 Activity and Glomerular Filtration Rate and Albuminuria Status in Patients With Type 2 Diabetes Mellitus

Diabetic nephropathy is pictured as matrix accumulation and thickening of glomerular basal membrane. Matrix metalloproteinases (MMPs) are major proteases involved in extracellular matrix degradation. Moreover, plasminogen activator inhibitor-1 (PAI-1) primarily regulates plasmin dependent proteolysis. It plays a role in renal fibrosis causing extracellular matrix accumulation through inhibition of plasmin-dependent extracellular matrix degradation. This study investigated PAI-1 serum level and MMP-3 activity and their correlation with glomerular filtration rate in patients with diabetes mellitus. In a case-control design, serum PAI-1 concentrations and MMP-3 activity were measured in 80 patients with normoalbuminuria, microalbuminuria, and macroalbuminuria. Receiver operating characteristics curve analysis was used to assess the diagnostic accuracy of MMP-3 activity in discriminating albuminuria. In the patients with microalbuminuria, serum PAI-1 levels were higher compared with macroalbuminuric patients (P < .001). The patients with macroalbuminuria exhibited a significantly lower MMP-3 activity than the patients with microalbuminuria and normoalbuminuria (P < .001). No significant correlation was found between serum MMP-3 activity and serum PAI-1 levels in those with normoalbuminuria, microalbuminuria, and macroalbuminuria. The MMP-3 activity had a strong positive correlation with estimated glomerular filtration (r = 0.853, P < .001). We found that there was a positive correlation between glomerular filtration rate and MMP-3 activity in diabetic patients. This concludes that MMP-3 may have a role in the pathogenesis of diabetic nephropathy progressions towards macroalbuminuria, and therefore, MMP-3 activity may be used in evaluating albuminuria status.