Urinary Proteomics as a Noninvasive Readout of Obesity-associated Inflammation.

Introduction: Obesity affects a large percentage of the population, and it is associated with many comorbidities. These pathologies often coincide with the presence of a low-grade chronic inflammatory state in individuals with obesity that can be measured using circulating inflammatory proteins. The objective of this study was to use a noninvasive approach to determine obesity-induced inflammation by measuring the urinary proteome of individuals with and without obesity. Methods: Morning urine samples were taken from normal-weight controls (n = 30) with a mean body mass index (BMI) of 22.8 kg/m2 and people with obesity (n = 58) with a mean BMI of 32.9 kg/m2. Further data regarding high-density lipoprotein, fat distribution, blood pressure, and waist circumference were available from the individuals with obesity. Using these samples, normalized protein expression data were obtained using the Olink Explore 384 inflammation panel. These data were analyzed using R to elucidate the differences in protein expression between the individuals with and without obesity. Results: Of the 384 inflammation proteins, 48 proteins had a P < .05 with false discovery rate correction between the persons with obesity and the persons without obesity. Network analysis revealed 5 different clusters of proteins with several clusters associated (P < .05) with circulating concentrations of high-density lipoprotein, waist circumference, and fat distribution in individuals with obesity. Conclusion: This paper shows that urine may represent a novel noninvasive approach to measure the state of inflammation in individuals with obesity using Olink targeted proteomics.