Early markers of obesity-related renal injury in childhood.

Childhood obesity has become a global epidemic. Recent epidemiological data suggest that obesity is associated with increased risk of renal injury in children. The onset of obesity-associated renal disease is insidious and asymptomatic, so early markers will be extremely useful in its prevention and treatment. Biomarker discovery can be focused on unbiased or biased (candidate) approaches. Unbiased approaches using innovative technologies, such as proteomics and metabolomics, have uncovered candidates that are emerging as plausible biomarkers for such renal disorders as obstructive uropathy and diabetic nephropathy. Biased approaches are based on hypotheses related to glomerular or tubular injury pathophysiology in obesity. Goknar et al. (Pediatric Nephrology 2014; doi: 10.1007/s00467-014-2829-0 ) recently evaluated early urine renal injury markers, namely, microalbuminuria, N-acetyl-beta-D-glucosaminidase (NAG), neutrophil gelatinase-associated lipocalin, and kidney injury molecule (KIM)-1, in obese children. They reported that obese children had higher urinary NAG and KIM-1 levels than healthy controls. Longitudinal observation studies are needed to evaluate whether these tubular damage markers are useful as early markers of renal injury in obese children.