Urinary Volatile Organic Compounds (VOCs): application in clinics

Volatile organic compounds (VOCs) are emitted from the human body reflecting the metabolic condition of an individual and creating a unique chemical signature that pathological or mental diseases and genetic disorders can alter by a qualitative and/or quantitative change in the odours. Accumulating evidence has shown that this "smellprint" can be crucial in diagnosing, monitoring and developing novel therapies of human disease. Among the various biological fluids, urine shows specific features that make it an option of choice for volatile metabolomic profiling. Many studies show that urinary VOCs could be perturbed in some physiological and pathological states, including several diseases and different dietary exposures . VOCs can be analysed as disease specific 'fingerprints' using gas chromatography (GC) coupled with mass spectrometry (MS). In this communication, we describe two studies based on solid-phase microextraction (SPME) coupled GC-MS. In the first study, the volatile urinary profile of 24 autistic and 21 healthy children was investigated. Urine samples were analyzed both under acid and alkaline pH, to profile a range of urinary components with different physicochemical properties. Bioanalytical data, submitted to data analysis, allowed us to discriminate autistic and control groups, and to identify 15 possible VOCs biomarkers. In the second study, the investigation of urinary VOCs profile allowed the discrimination of 21 overweight/obese (OW/Ob) and 28 normal-weight (NW) children. Samples were analyzed both under acidic and alkaline conditions. Univariate and multivariate statistics permitted to distinguish two clusters of cases and discover 14 VOCs able to characterize the two groups.