Association of serum syndecan-1 concentrations with albuminuria in type 2 diabetes.

INTRODUCTION: Syndecan (SDC)-1 is a transmembrane heparan sulfate proteoglycan and is a major component of endothelial glycocalyx (EG). This study aimed to investigate the association of serum SDC-1 concentration as a marker of EG degradation with albuminuria in type 2 diabetes. METHODS: We included 370 patients with type 2 diabetes and 219 individuals with no diabetes. The individuals with estimate glomerular filtration rate <30 mL/min/1.73 m2 were excluded. RESULTS: Serum SDC-1 concentration was higher in type 2 diabetes than in no diabetes. The presence of diabetes was independently associated with log [SDC-1] in multivariate analysis. In type 2 diabetes, serum SDC-1 concentration was correlated with log [urinary albumin-to-creatinine ratio (ACR)]. Moreover, log [SDC-1] was an independent determinant of log [ACR] after adjustment for known risk factors of albuminuria. CONCLUSIONS: Serum SDC-1 concentration was higher in patients with type 2 diabetes compared to individuals with no diabetes and an independent determinant of ACR. This study implicates the role of the EG degradation in albuminuria in type 2 diabetes.

Association of xanthine oxidoreductase inhibitor use with insulin secretory capacity in patients with type 2 diabetes.

AIM/INTRODUCTION: Xanthine oxidoreductase (XOR) inhibitor treatment, which reduces reactive oxygen species (ROS) production and increases adenosine triphosphate (ATP) synthesis, has been reported to improve glycemic control. The possible protective effects of XOR inhibitor treatment on insulin secretory capacity were investigated in patients with type 2 diabetes. MATERIALS AND METHODS: This retrospective cross-sectional study included 428 patients with type 2 diabetes. Insulin secretory capacity was assessed based on fasting serum C-peptide concentration (CPR) and C-peptide index (CPI) in all subjects, while insulin resistance in non-insulin users (n = 312) was determined using the homeostasis model assessment of insulin resistance (HOMA-IR) index. RESULTS: Median values for CPR and CPI in all subjects were 2.4 ng/mL and 1.5, respectively, while that for HOMA-IR in non-insulin users was 3.2. The XOR inhibitor users (n = 72) had significantly (P < 0.001) higher CPR and CPI levels than non-users (n = 356). Multivariable regression analyses showed XOR inhibitor use was positively associated with CPR (ß = 0.153, P = 0.001) and CPI (ß = 0.144, P = 0.001). Similar results were observed in propensity score analyses. In subgroup analyses of patients with a preserved estimated glomerular filtration rate (≥60 mL/min/1.73 m2) and non-insulin users, these associations remained significant. Furthermore, the associations were significant in patients with lower (≤6.0 mg/dL) but not with higher (>6.0 mg/dL) uric acid levels (P for interaction <0.05). On the other hand, XOR inhibitor use showed no significant association with HOMA-IR. CONCLUSIONS: The results of XOR inhibitor treatment, especially a sufficient reduction in serum uric acid level, may provide protective effects on insulin secretory capacity in patients with type 2 diabetes.