Kidney Week

Abstract: FR-PO1208

Evaluating the Role of Urinary Volatile Organic Compounds in CKD

Session Information

• CKD: Mechanisms - 2
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2303 CKD (Non-Dialysis): Mechanisms

Authors

• Wu, Henry, Kolling Institute of Medical Research, St Leonards, New South Wales, Australia

Henry Wu, MBChB

• Possell, Malcolm, The University of Sydney, Sydney, New South Wales, Australia

Malcolm Possell, PhD

• Nguyen, Long T., Kolling Institute of Medical Research, St Leonards, New South Wales, Australia

Long T. Nguyen, PhD

• Peng, Wenbo, University of Technology Sydney, Sydney, New South Wales, Australia

Wenbo Peng, MD, PhD

• Pollock, Carol A., Kolling Institute of Medical Research, St Leonards, New South Wales, Australia

Carol A. Pollock, MD, MBBS, PhD

• Saad, Sonia, Kolling Institute of Medical Research, St Leonards, New South Wales, Australia

Sonia Saad, PhD

Background

Volatile organic compounds (VOCs) are gaseous products of metabolic processes in organisms which are conventionally released with greater abundance in disease. Whether urinary VOCs are valuable as a non-invasive source in reflecting CKD status is unclear.

Methods

Adults aged 18-75 years with kidney biopsy performed were included. All biopsy samples had an interstitial fibrosis and tubular atrophy (IFTA) grade scored by standardized assessment. Pre-biopsy urine were collected. Urine supernatant was extracted from residue and sampled for stir bar sorptive extraction, followed by gas chromatography–mass spectrometry (GC-MS). Post-processing of GC-MS data involved measuring mass-to-charge ratios and fragment patterns for identification and quantification of individual VOCs. Linear discriminant analysis (LDA) assessed the ability of urinary VOCs in discriminating between no IFTA, ≤25% (mild) IFTA and >25% (moderate/severe) IFTA. Linear regression analysis adjusting for age, sex, eGFR and diabetes mellitus status was conducted to determine significantly upregulated urinary VOCs with IFTA progression.

Results

64 study participants were included (22 individuals no IFTA, 15 individuals mild IFTA, 27 individuals moderate/severe IFTA). LDA demonstrated individuals with no IFTA, mild, and moderate/severe IFTA could easily be separated by their urinary VOCs profile (see figure). 34 VOCs were identified to be helpful in correctly classifying between the IFTA groups, of which 7 VOCs were significantly upregulated in the mild IFTA compared to the no IFTA group and 3 VOCs were significantly upregulated in the moderate/severe IFTA compared to the mild IFTA group (p<0.05). 'Benzaldehyde, 4-methyl' is positively associated with IFTA progression across all stages (p<0.05).

Conclusion

We report novel links between urinary VOCs and tubulointerstitial histopathology. Urinary VOCs may have a clinical diagnostic role in CKD going forward.

Funding

• Government Support – Non-U.S.