Reactive aldehydes as potential biomarkers for diabetic nephropathy detection, stratification and disease progression

Abstract

Diabetic nephropathy (DN) is currently the leading cause of end-stage renal disease. Limitations in current diagnostic methods have highlighted a need for alternative, selective biomarkers which are detectable prior to irreversible renal damage. In this study, reactive products of oxidative reactions, reactive aldehydes (RAs), such as di-carbonyls and β-unsaturated aldehydes were assessed in three DN models: in vitro renal proximal tubule cell models, the kidneys of a diabetic mouse model and in a cohort of Type 2 diabetic (T2DM) and DN participants.

Elevated levels of several RAs were detected via LC-MS in renal proximal tubule epithelial cells of both mouse and human origin, when cultured under increasing concentrations of glucose. Similarly, increased levels were detected in the kidney homogenate of diabetic mouse models culled at various time points mimicking stages of DN progression. Furthermore, the elevated presence and localisation of 4-hydroxyhexenal, 4-oxo-2-nonenal and 4-hydroxynonenal was demonstrated in kidney tissue using MALDI-FTICR-MSI with Girard’s reagent T in an on-tissue chemical derivatisation method. Untargeted lipid analysis revealed significant alterations in the renal lipid profile of diabetic mice.

Analysis of participant plasma and urine samples revealed increased levels of RAs in T2DM and DN participants in comparison to healthy controls. Plasma concentrations of 4-hydroxynonenal, pentanal, methylglyoxal, glyoxal and urinary 4-oxo-2-nonenal were significantly different between T2DM and DN groups (p < 0.01). Further, biomarkers of renal injury and inflammation, such as transferrin, neutrophil gelatinase-associated lipocalin and interleukin-6, were also identified as effective markers of DN, in both serum and urine. In conclusion, this translational project demonstrated the utility of RAs as DN biomarkers in three separate models. The performance of RAs and markers of kidney dysfunction is promising for their combined utility as a panel of biomarkers which can be used in the early screening of DN in T2DM patients in a clinical setting.

Date of Award	Oct 2021
Original language	English
Sponsors	Randox Laboratories Ltd.
Supervisor	Tara Moore (Supervisor), Diego Cobice (Supervisor) & Simon Brockbank (Supervisor)