Urinary fatty acid binding protein as a new clinical marker for the progression of chronic renal disease

As free fatty acids are loaded into the proximal tubule during various kinds of stresses and become cytotoxic, they may play an important role in the progression of renal disease. The proximal tubular epithelial cells express liver-type fatty acid binding protein(L-FABP), an intracellular carrier protein of fatty acids. We hypothesized that urinary L-FABP reflected stresses on the proximal tubule and thus presents a new clinical marker for the progression of renal disease.ELISA for L-FABP was established and relations between urinary L-FABP and clinical parameters from non-diabetic chronic renal disease (n = 120) were evaluated.Laboratory data revealed a correlation between urinary L-FABP and urinary protein (F = 22.7), urinary alpha 1-microglobulin (F = 13.9) and serum creatinine (F = 11.4). Notably only urinary L-FABP at the start of follow-up (F = 17.1) was selected as a significant clinical factor correlated with the progression rate defined as a slope of a reciprocal of serum creatinine over time. The results indicated that urinary L-FABP was correlated with the clinical prognosis of renal disease.Urinary L-FABP is a new clinical marker for predicting the progression of chronic glomerular disease.