A PAI-1 mutant, PAI-1R, slows progression of diabetic nephropathy

Plasminogen activator inhibitor-1 (PAI-1) has been implicated in renal fibrosis. In vitro, PAI-1 inhibits plasmin generation, and this decreases mesangial extracellular matrix turnover. PAI-1R, a mutant PAI-1, increases glomerular plasmin generation, reverses PAI-1 inhibition of matrix degradation, and reduces disease in experimental glomerulonephritis. This study sought to determine whether short-term administration of PAI-1 R could slow the progression of glomerulosclerosis in the db/db mouse, a model of type 2 diabetes in which mesangial matrix accumulation is evident by 20 wk of age. Untreated uninephrectomized db/db mice developed progressive albuminuria and mesangial matrix expansion between weeks 20 and 22, associated with increased renal mRNA encoding alpha 1(I) and (IV) collagens and fibronectin. Treatment with PAI-1 R prevented these changes without affecting body weight, blood glucose, glycosylated hemoglobin, creatinine, or creatinine clearance; therefore, PAI-1 R may prevent progression of glomerulosclerosis in type 2 diabetes.