ASSOCIATION OF BMP-7 WITH C-PEPTIDE LEVELS: A MARKER OF β-CELL RESERVE IN TYPE 2 DIABETES MELLITUS
Keywords:
BMP-7, bone morphogenetic protein-7, diabetic nephropathy, chronic kidney disease, type 2 diabetes mellitus, C-peptide, albuminuria, glomerular filtration rateAbstract
Objective. To evaluate serum BMP-7 levels in patients with type 2 diabetes mellitus (T2DM) and to assess their associations with clinical and laboratory parameters according to chronic kidney disease (CKD) phenotypes defined by glomerular filtration rate (GFR) and albuminuria status. Materials and Methods. A total of 153 patients with T2DM were enrolled and classified into four phenotypic groups: NRF/NA (normal renal function/normoalbuminuria, n=35), DRF/NA (decreased renal function/normoalbuminuria, n=35), NRF/EA (normal renal function/elevated albuminuria, n=35), and DRF/EA (decreased renal function/elevated albuminuria, n=30). Eighteen healthy individuals served as controls. Serum BMP-7 levels were measured using enzyme-linked immunosorbent assay (ELISA). Outliers were excluded before analysis based on Tukey’s method and physiological plausibility assessment. Group comparisons were performed using the Kruskal–Wallis test followed by Dunn’s post-hoc analysis, with Benjamini–Hochberg false discovery rate (FDR) correction for multiple testing. Effect sizes (ε²) were reported. Associations were evaluated using Spearman’s correlation analysis. Results. After FDR correction, no statistically significant differences in BMP-7 levels were observed between the study groups (q=0.092). In the overall T2DM cohort (n=135), the only significant correlation of BMP-7 was found with C-peptide levels (ρ=0.176; p=0.030). No significant associations were observed with GFR, albuminuria, cystatin C, C-reactive protein (CRP), HbA1c, or proBNP (p>0.05). The highest BMP-7 concentrations were detected in the NRF/EA (146±35.9 pg/mL) and DRF/NA (145±31.5 pg/mL) groups. Conclusion. In established CKD, serum BMP-7 is not a discriminative biomarker of renal phenotype in patients with T2DM. Its positive association with C-peptide suggests a potential role of BMP-7 in supporting pancreatic β-cell functional activity.
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