Fatty acid-binding protein as marker for renal injury.

The assessment of biomarkers to detect renal injury has been studied before, but the sensitivity and specificity of urinary and serum profiles of these markers still need to be improved. One of the promising new markers for detection of renal injury is the family of 15 kDa cytoplasmic fatty acid-binding proteins (FABPs). Remarkably, however, the application of FABP as marker for renal injury due to ischaemia, toxic heavy metals or in end-stage renal failure has only recently been investigated. The present status of two types of FABP in the kidney (heart-type (H-FABP), located in the distal tubular cells, and liver-type (L-FABP), which is located in the proximal tubular cells), is reviewed for sensitive detection of renal injury. This review is based on an overview of the literature on clinical diagnostics applying plasma and urinary H-FABP as well as L-FABP levels in renal toxicity, kidney transplantation or as clinical parameter in end-stage renal failure. H-FABP has been shown to be a proper marker for detection of ischaemic injury in tissue perfusates of non-heart-beating donor kidneys. Urinary L-FABP has been evaluated recently more explicitly and shows significant elevations in progressive end-stage renal failure as well as after ischaemic injury due to renal transplantation or cardiac bypass surgery. H- and L-FABP have been shown to be useful markers for rapid detection and monitoring of renal injury. Further study of the diagnostic and prognostic use of these FABP types will require further commercialization of automated and rapid assays for proper clinical application.