Clinical Significance of Urinary Liver-Type Fatty Acid–Binding Protein in Patients With Diabetic Nephropathy
- Kumi Suzuki, MD12,
- Tetsuya Babazono, MD, PHD12,
- Hidekazu Murata, MT1 and
- Yasuhiko Iwamoto, MD, PHD2
- 1Division of Nephrology and Hypertension, Diabetes Center, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
- 2Department of Medicine, Diabetes Center, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
- Address correspondence and reprint requests to Tetsuya Babazono, MD, PhD, Division of Nephrology and Hypertension, Diabetes Center, Tokyo Women’s, Medical University School of Medicine, 8-1 Kawadacho, Shinjukuku, Tokyo 162-8666, Japan. E-mail: babazono{at}dmc.twmu.ac.jp
- ACR, albumin-to-creatinine ratio
- FABP, fatty acid–binding protein
- FFA, free fatty acid
- GFR, glomerular filtration rate
- l-FABP, liver-type FABP
Tubulointerstitial damage plays a crucial role in the progression of kidney diseases, including diabetic nephropathy (1). Among several distinct types of fatty acid–binding protein (FABP), liver-type FABP (l-FABP) is abundantly expressed in hepatocytes and constitutively expressed in proximal tubular cells of the kidney (2). l-FABP incorporates albumin-bound free fatty acids (FFAs) that are filtered through the glomeruli into proximal tubular cells and transports FFAs from the cytosol to the nucleus (3). In transgenic mice expressing human l-FAPB, protein overload, resulting in massive proteinuria, upregulated renal l-FABP expression and increased its urinary excretion (4), suggesting that urinary l-FABP may reflect tubulointerstitial damage. Recently, in patients with nondiabetic glomerular disease, urinary excretion of l-FABP increased in parallel with the severity of tubulointerstitial injury and correlated with proteinuria and the rate of progression of renal disease, suggesting that l-FABP may be a useful indicator for the progression of nondiabetic kidney disease (4,5). To determine the clinical significance of l-FABP in patients with diabetic nephropathy, we conducted a cross-sectional study comparing urinary l-FABP excretion in diabetic patients with serial stages of kidney disease.
RESEARCH DESIGN AND METHODS
Adult patients with type 2 diabetes were recruited from the outpatient clinic of the Division of Nephrology and Hypertension, Diabetes Center, Tokyo Women’s Medical University …
