Preserved C-peptide secretion in patients with type 1 diabetes and incipient chronic complications is associated with lower serum resistin and higher uric acid levels.

Background And Aims: Previous studies suggested that long-term perseverance of beta-cell function in patients with type 1 diabetes (T1DM) is associated with lower incidence of microvascular complications. The objective of this study was to evaluate preserved C-peptide secretion in patients with T1DM without overt chronic complications and to explore associations with resistin and uric acid as biomarkers of microvascular complication pathogenesis.

Materials And Methods: We assessed residual beta-cell function in 164 T1DM patients (male/female = 91/73; age/diabetes duration range = 18-70/1-30 years) using an ultrasensitive C-peptide ELISA assay with detection limit of 2.5 pmol/L and total coefficient of variation (CV) 5,8% (Mercodia, Sweden). Serum level of uric acid was measured by enzymatic method (AU680, Beckman Coulter, USA) while resistin concentration was determined by the ELISA assay (Biovendor, Czech Republic).

Results: C-peptide secretors had shorter diabetes duration (5.1 vs. 16 years;  < 0,001), lower resistin (4.53 vs. 4.93 mg/mL  = 0.045), and higher uric acid (259 vs 238 μmol/L,  = 0.048) level than T1DM patients with no detectable C-peptide levels, while no differences in routine anthropometric and laboratory variables, including HbA1c, were observed. Although the proportion of C-peptide secretors significantly decreased across categories of diabetes duration (70%, 38%, 17% and 15% for <5, 5-10, 10-20 and 20-30 years of duration, respectively;  < 0,001), detectable C-peptide was found in 5/23 T1DM patients who were diagnosed with T1DM more than 20 years ago.

Conclusion: The results of our study revealed that patients with detectable C-peptide had lower resistin and higher uric acid level compared to patients with undetectable C-peptide.