OBJECTIVE -Liver-type fatty acid-binding protein (L-FABP) is expressed in renal proximal tubules and is reported to be a useful marker for progression of chronic glomerulonephritis. The aim of this study was to determine whether urinary L-FABP levels are altered at various stages of diabetic nephropathy and whether pitavastatin affects urinary L-FABP levels in early diabetic nephropathy.RESEARCH DESIGN AND METHODS -Fifty-eight patients with type 2 diabetes (34 men and 24 women, median age 52 years) and 20 healthy, age-matched subjects (group E) were recruited for the study. The diabetic patients included 12 patients without nephropathy (group A), 20 patients with microalbuminuria (group B), 14 patients with macroalbuminuria and normal renal function (group C), and 12 patients with chronic renal failure but not undergoing hemodialysis (blood creatinine Ͼ1.2 mg/dl; mean 2.5 mg/dl, group D). Twenty group B patients were randomly assigned to receive 1 mg/day pitavastatin (10 patients, group B1) or placebo (10 patients, group B2). Treatment was continued for 12 months. Urinary L-FABP levels were measured by enzyme-linked immunosorbent assay. Urinary 8-hydroxydeoxyguanosine and serum free fatty acids (FFAs) were also measured in group B.RESULTS -Urinary L-FABP levels in groups A-D were 6.2 Ϯ 4.6 g/g creatinine, 19.6 Ϯ 13.5 g/g creatinine, 26.8 Ϯ 20.4 g/g creatinine, and 52.4 Ϯ 46.8 g/g creatinine, respectively. Urinary L-FABP levels in groups B-D were significantly higher than those in healthy subjects (group E, 5.8 Ϯ 4.0 g/g creatinine) (group B, P Ͻ 0.05; group C, P Ͻ 0.01; group D, P Ͻ 0.01). In group B1, urinary albumin excretion (UAE) and urinary L-FABP levels were decreased after pitavastatin treatment (UAE before, 110 Ϯ 74 g/min; 6 months, 88 Ϯ 60 g/min, P Ͻ 0.05; 12 months, 58 Ϯ 32 g/min, P Ͻ 0.01; L-FABP before, 18.6 Ϯ 12.5 g/g creatinine; 6 months, 12.2 Ϯ 8.8 g/g creatinine, P Ͻ 0.05; 12 months, 8.8 Ϯ 6.4 g/g creatinine, P Ͻ 0.01). In group B2, UAE and L-FABP levels showed little change during the experimental period. In group B1, urinary 8-hydroxydeoxyguanosine was decreased 12 months after pitavastatin treatment (before 32.5 Ϯ 19.5 ng/mg creatinine, after 18.8 Ϯ 14.5 ng/mg creatinine, P Ͻ 0.01), but in group B2, these showed little difference during the experimental period. In both groups B1 and B2, serum FFAs showed little difference during the experimental period.CONCLUSIONS -Urinary L-FABP levels appear to be associated with the progression of diabetic nephropathy, and pitavastatin may be effective in ameliorating tubulointerstitial damage in early diabetic nephropathy. Diabetes Care 28:2728 -2732, 2005D iabetes-associated nephropathy is the leading cause of end-stage renal disease. The pathogenesis of diabetic nephropathy is multifactorial, and the precise mechanisms are unclear. It is now widely accepted that the rate of functional deterioration correlates with the degree of renal tubulointerstitial fibrosis (1). Epithelial cells of the proximal tubules play a major role in orchestrating events in the...

Evaluations of glomerular mRNA levels encoding for PCNA, TNF-alpha, PDGF-A and -B chains, TGF-beta, IGF-I, bFGF, and EGF were made at 4, 12, and 24 wk after injection of STZ in Sprague-Dawley rats. The mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF increased with age in STZ-induced diabetic rats. At 24 wk after STZ injection, mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF were increased 3.8-fold, (P < 0.01), 4.2-fold (P < 0.01), 4.0-fold (P < 0.01), 5.2-fold (P < 0.001), and 3.6-fold (P < 0.01), respectively, in the glomeruli of diabetic rats when compared with control rats. In contrast, mRNA levels for IGF-I, PDGF-A chain, and EGF were not altered in glomeruli from diabetic and control rats throughout the experimental period. Insulin treatment partially ameliorated the increase in mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF in the glomeruli of diabetic rats. These data indicate that alterations in growth factor mRNA levels in glomeruli may be a manifestation of diabetic nephropathy, and that hyperglycemia or insulin deficiency may play a role in abnormal growth factor gene regulation.

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