Salivary metabolic profile of children and adolescents after hemodialysis

Introduction The application of metabolomic analysis in the pediatric nephrology field may offer an innovative approach to profile analysis of renal diseases. Objective We aimed to analyze the salivary the major metabolites in the saliva of children and adolescents with chronic kidney disease (CKD) before and after hemodialysis. Method Thirty-six children diagnosed with CKD and forty healthy children were recruited for the study. H-1-NMR spectra were analyzed using multivariate and univariate approaches. Results The CKD and the healthy control groups presented with similar numbers of dental caries (p > 0.05) as determined by the number of decayed, missing, or filled deciduous teeth (0.87 +/- 2.2 and 0.67 +/- 2.1, respectively) or permanent teeth (0.79 +/- 1.30 and 0.90 +/- 1.7, respectively). The amount of dental calculus was significantly higher in the CKD group than in the healthy control group (p < 0.001). Multivariate analyses using PLS-DA and O-PLS-DA demonstrated differences in the salivary metabolome of CKD patients before and after hemodialysis, as well as between post-dialysis CKD patients and healthy controls, suggesting that HD was not able to recover oral homeostasis. PLSDA and OPLS-DA models showed satisfactory accuracy (ACC = 0.72) and prediction (0.64). On multivariate and univariate analyses, urea, acetate, ethanol, and fatty acid were significantly decreased in CKD saliva after hemodialysis. By contrast, saliva from the healthy controls had significantly higher levels of acetate and propionate and lower levels of ethanol, lactate, butyrate, phenylalanine, and creatinine than saliva from post-dialysis CKD patients. Conclusion Our results demonstrate that hemodialysis alters the expression of salivary metabolites; however, this alteration does not reestablish the healthy salivary metabolome, as the salivary metabolomic profile of healthy children is significantly different from that of children and adolescents with CKD, both before and after hemodialysis. The unique salivary characteristics of children with CKD may influence their oral health status.