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.