Chronic kidney disease in children: Using novel biomarkers as predictors of disease.

Chronic kidney disease (CKD) in children contributes to the global health burden. The focus on using novel biomarkers to predict the onset and progression of the disease has increased tremendously over the past decade. Discovery of these biomarkers offers prospects for the early anticipation of the late stages of CKD, slowing down disease progression, and achieving better disease outcomes. The aim of this article is to classify and highlight the utility of these novel biomarkers in predicting disease-onset and progression. Biomarkers of CKD are broadly classified into biomarkers of kidney function and biomarkers of kidney damage. Glomerular filtration rate (GFR) remains the most important marker of kidney function, but it cannot be easily measured in most clinical and research settings. Its estimating equations, therefore, depend on filtration biomarkers such as serum creatinine and serum cystatin C. For instance, the CKD-epidemiology collaboration equation has been suggested as the preferred prediction equation for the staging and classification of estimated GFR (eGFR) in CKD. Although albuminuria is the traditional biomarker of kidney damage, it precedes any decline in eGFR and may be absent in tubulointerstitial disease. Thus, more sensitive and specific novel biomarkers of kidney damage are emerging which hold prospects for earlier prediction of CKD in children. They have been classified as tubular and miscellaneous biomarkers. Tubular biomarkers are represented by markers such as kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, N-acetyl-ß-D glucosaminidase, liver-type fatty-acid binding protein, cystatin C and a-1-microglobulin. Miscellaneous biomarkers include monocyte chemoattractant protein-1, interleukin-18, and retinol binding protein 4. Despite their advantages over albuminuria, they still require validation before they can be applied in clinical practice.