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The following is a summary of “Evaluation of urinary volatile organic compounds as a novel metabolomic biomarker to assess chronic kidney disease progression,” published in the October 2024 issue of Nephrology by Wu et al.
Non-invasive methods are needed to evaluate chronic kidney disease (CKD) and its progression. Dysregulated metabolic pathways in CKD support the use of Volatile Organic Compounds (VOCs) as potential biomarkers.
Researchers conducted a retrospective study to investigate how urinary VOCs reflect the metabolic profile in patients with CKD.
They included individuals aged 18–75 years undergoing kidney biopsy and collected pre-biopsy urine samples. Using a standardized method, biopsy samples were graded for interstitial fibrosis and tubular atrophy (IFTA). Urine supernatant underwent stir bar sorptive extraction and gas chromatography-mass spectrometry (GC-MS) analysis. They processed GC-MS data to separate VOC mixtures by volatility and polarity, measuring mass-to-charge ratios for identification and quantification. Linear discriminant analysis (LDA) differentiated between IFTA grades (0: <10%, 1: 10–25%, ≥2: >25%). Adjusted linear regression analysis identified significantly regulated urinary VOCs among the groups.
The results showed that 64 participants were included (22 individuals IFTA 0, 15 individuals IFTA 1, 27 individuals IFTA ≥2). GC-MS identified 34 VOCs associated with classification among IFTA groups, with LDA separating IFTA 0, IFTA 1, and IFTA ≥2 based on urinary VOC profiles (P<0.001). Multivariate linear regression revealed 4 VOCs significantly upregulated in IFTA 1 compared to IFTA 0 and 2 VOCs upregulated in IFTA ≥2 compared to IFTA 1 (P<0.05). The upregulated VOCs belonged to 4 functional groups: aldehydes, ketones, hydrocarbons, or alcohols.
The study concluded that urinary VOCs were linked to tubulointerstitial histopathology, indicating their potential as non-invasive metabolomic biomarkers for assessing CKD status and progression.
Source: bmcnephrol.biomedcentral.com/articles/10.1186/s12882-024-03819-0#Abs1
