Short-term renal and metabolic effects of low dose vildagliptin treatment added-on insulin therapy in non-proteinuric patients with type 2 diabetes: open-label randomized prospective study

Objective The aim of this randomized comparative study was to assess renal and metabolic effects of vildagliptin in insulin-treated type 2 diabetes (T2DM) patients without overt chronic kidney disease. Subjects and methods We randomized 47 insulin-treated non-proteinuric patients with satisfactory controlled T2DM and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m 2 either to continue insulin therapy (control) or to receive combined insulin-vildagliptin treatment (VIG group). We assessed eGFR using serum creatinine (eGFRcreat), cystatin C (eGFRcys), and both (eGFRcreat-cys), and urinary creatinine-adjusted excretion of albumin (UACR), type IV collagen (uCol IV/Cr), and neutrophil gelatinase-associated lipocalin (uNGAL/Cr) at baseline and after 6 months of treatment. Results Study groups were comparable in terms of age and sex (60.1 ± 6.1 years and 42.9% men in control group vs. 60.8 ± 5.2 years and 39.1% in VIG group). After 6 months of treatment, there were no significant changes in main assessed parameters in control group. VIG group demonstrated significant decrease in HbA1c, diastolic blood pressure, frequency of hypoglycemia, and high-sensitivity C-reactive protein level as compared to the changes in control group. While eGFRcreat, UACR, and uNGAL/Cr showed no significant changes after vildagliptin addition, eGFRcys, eGFRcreat-cys, and uCol IV/Cr changed significantly in comparison with control group (+7.0% [3.7;13.3]; +5.1% [1.4;8.5]; -32,8% [-55.8;-24.4], respectively, p < 0.01 each). Correlation and regression analysis revealed glucose-independent pattern of these changes. Conclusion Addition of vildagliptin to ongoing insulin therapy in patients with T2DM was associated with a reduction in uCol IV/Cr and an increase in eGFRcys and eGFRcreat-cys, independent of T2DM control parameters.

Association between serum insulin like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 levels and chronic kidney disease in diabetic patients

Introduction: Insulin-like growth factor-1 (IGF-1) is a potent mitogen for glomerular mesangial cells which can stimulate cell migration and the production of fibronectin, proteoglycan, and type IV collagen, thereby promoting the development of the chronic kidney disease (CKD) in patients with diabetes. Objectives: The aim of the study was to assess the associations between serum levels of IGF-1 and insulin-like growth factor-binding protein-3 (IGFBP-3) and CKD in diabetic patients. Patients and Methods: We investigated 102 Belarusian men and women with diabetes type 2 aged 56.67±0.81 years. Control group included 68 healthy people the same age. We estimated GFR with the use of the CKD-EPI creatinine-cystatin C equation to determine eGFRcr_cys. Serum total IGF-1 and IGFBP-3 levels were measured using immunoradiometric assay (IRMA) (Beckman Coulter, Czech Republic s.r.o.). Results: Patients with diabetes had significantly lower level of IGF-1 than controls. However, IGFBP-3 levels were similar in the two groups. Diabetic patients with CKD had significantly higher levels of IGF-1 and IGFBP-3 than diabetic patients without CKD (P=0.0031). However, according to multivariate analysis, only IGF-1 and cystatin C were associated with renal impairment. In detail, the odds of having eGFR<60 mL/min/1.73 m2 increased with rising IGF-1 levels (OR: 1.025, [CI 1.002-1.048]). Conclusion: Our study revealed that higher serum IGF-1 levels were positively associated with CKD in patients with diabetes. We suggest that IGF-1 might be a predictor of CKD in patients with diabetes. Further research is necessary to confirm the observed this association and to detect the causal relations.