Metabolites related to eGFR: Evaluation of candidate molecules for GFR estimation using untargeted metabolomics.

Background: Metabolomics can be used to identify novel metabolites related to renal function and that could therefore be used for estimating GFR. We evaluated metabolites replicated and related to eGFR in 3 studies (CKD and general population).
Methods: Metabolomics was performed by GC-MS. The Progredir Cohort (n = 454, class 3 and 4 CKD) was used as the derivation study and adjusted linear regression models on eGFR-CKDEPI were built. Bonferroni correction was applied for selecting metabolites to be independently validated in the Diabetic Nephropathy Study (n = 56, macroalbuminuric DN) and in the Baependi Heart Study (BHS, n = 1145, general population).
Results: In the Progredir Cohort, 72 metabolites where associated with eGFR. Of those, 11 were also significantly associated to eGFR in the DN Study and 8 in the BHS. Four metabolites were replicated and significantly associated to eGFR in all 3 studies: d-threitol, myo-inositol, 4-deoxierythronic acid and galacturonic acid. In addition, pseudouridine was strongly correlated to eGFR only in the 2 CKD populations.
Conclusions: Our results demonstrate metabolites that are potential biomarkers of renal function: d-threitol, myo-inositol, 4-deoxierythronic acid, galacturonic acid and pseudouridine. Further investigation is needed to determine their performance against otherwise gold-standard methods, most notably among those with normal eGFR.
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