A Specific Urinary Amino Acid Profile Characterizes People with Kidney Stones

Abstract

Background. Urolithiasis is the process of stone formation in the urinary tract. Its etiology is only partly known, and efficient therapeutic approaches are currently lacking. Metabolomics is increasingly used in biomarkers discovery for its ability to identify mediators of relevant (patho)physiological processes. Amino acids may be involved in kidney stone formation. The aim of the present study was to investigate the presence of an amino acid signature in stone former urine through a targeted metabolomic approach. Methods. A panel of 35 amino acids and derivatives was assessed in urines from 15 stone former patients and 12 healthy subjects by UPLC-MS. Partial Least Squares Discriminant Analysis (PLS-DA) was used to define amino acid profiles of cases and controls. Results and Discussion. Our approach led to the definition of a specific amino acid fingerprint in people with kidney stones. A urinary amino acid profile of stone formers was characterized by lower levels of α-aminobutyric acid, asparagine, ethanolamine, isoleucine, methionine, phenylalanine, serine, tryptophan, and valine. Metabolomic analysis may lend insights into the pathophysiology of urolithiasis and allow tracking this prevalent condition over time.

Normative Data on Serum and Plasma Tryptophan and Kynurenine Concentrations from 8089 Individuals Across 120 Studies: A Systematic Review and Meta-Analysis

“…The sample matrices reported in this study suggest that there is a growing interest in minimally invasive sample types. The majority (66.67%) of the TRP urine papers have been published since 2015, 28 , 53 , 57 , 63 , 90 , 96 , 110 , 124 , 134 , 136 while all included TRP saliva studies were published within this timeframe. 38 , 71 Saliva metabolomics is an emerging field of research due to the diversity of metabolites present and the relative ease in sampling including decentralised approaches.…”

Methods for the dietary assessment of adult kidney stone formers: a scoping review

“…New urinary biomarkers have been identified [ 44 ] and metabolomic studies are promising. For instance, a study identified a urinary amino acid profile specific to kidney stone formers [ 25 ].…”

“…Furthermore, as the search equations did not include metabolomics, we conducted a focus search in PubMed with the terms “metabolomics” and “kidney stones” in January 2021. This search gave 16 results, two publications were selected and added to the review [ 24 , 25 ].…”

Serum metabolomics study reveals a distinct metabolic diagnostic model for renal calculi

“…In recent years, there has been a rapid increase in the use of metabolomics for the treatment of RC due to the development and popularization of metabolomics technology. Some researchers have already conducted metabolic profiling on the urine of RC patients using 1H NMR [ 8 , 9 ] and targeted amino acid methods [ 10 ]. Reports on untargeted metabolomics [ 11 ], lipid metabolism [ 12 ], and bile acid metabolism [ 13 ] in animal models of RC are also on the rise.…”