EFFECTS OF DIPEPTIDYL PEPTIDASE-4 INHIBITION ON ENDOTHELIAL NITRIC OXIDE RELEASE, BLOOD PRESSURE AND SICAM-1 LEVELS IN HYPERTENSIVE RATS

Clinical and genetic predictors of dipeptidyl peptidase-4 inhibitor treatment response in Type 2 diabetes mellitus

AIM

To determine the clinical and genetic predictors of the dipeptidyl peptidase-4 (DPP-4) inhibitor treatment response in Type 2 diabetes mellitus (T2DM) patients.

PATIENTS & METHODS

DPP4, WFS1 and KCNJ11 gene polymorphisms were genotyped in a cohort study of 662 T2DM patients treated with DPP-4 inhibitors sitagliptin, vildagliptin or linagliptin. Genotyping was performed by Applied Biosystems TaqMan SNP genotyping assay.

RESULTS

Patients with triglyceride levels less than 1.7 mmol/l (odds ratio [OR]: 2.2.; 95% CI: 1.031-4.723), diastolic blood pressure (DBP) less than 90 mmHg (OR: 1.7; 95% CI: 1.009-2.892) and KCNJ11 rs2285676 (genotype CC) (OR: 2.0; 95% CI: 1.025-3.767) were more likely to response to DPP-4 inhibitor treatment compared with other patients, as measured by HbA1c levels.

CONCLUSION

Triglycerides, DBP and KCNJ11 rs2285676 are predictors of the DPP-4 inhibitor treatment response in T2DM patients.

Circulating dipeptidyl peptidase-4 activity is associated with insulin resistance in type 1 diabetic patients

AIM

The pathophysiology of insulin resistance (IR) comprises a complex adipokine mediated cross-talk between white adipose tissue and other organs. Dipeptidyl peptidase-4 (DPP4) is protease recently proposed as a novel adipokine linked to IR. We aimed to assess the relationship between fasting serum DPP4 activityand IR in type 1 diabetic (T1DM) patients.

METHODS

A cross-sectional study comprised 44 T1DM patients aged >18 and <65years. IR was esimated using the equation for insulin sensitivity derived from euglycemic-hyperinsulinemic clamp studies-estimated glucose disposal rate (eGDR). DPP4 serum activity was determined spectrophotometrically as a rate of cleavage of 7-Amino-4-Methyl Coumarin (AMC) from H-Gly-Pro-AMC.

RESULTS

Patients were divided according to DPP4 activity tertiles (<25.40; ≥36.54 U/L). Fasting serum DPP4 activity was related to disease duration (p=0.012), systolic (p=0.009) and diastolic (p=0.047) blood pressure, waist circumference (p=0.037), urine albumin excretion (p=0.022) and conversely related to eGDR (p=0.004). The linear regression has shown that eGDR decreases for 0.203 mgkg(-1)min(-1) by each increase of serum DPP4 activity of 1 U/L (p<0.001) after adjustment for adjusted for age, gender, disease duration, albuminuria and the use of antihypertensives and statins.

CONCLUSION

Serum DPP4 activity is associated with IR in T1DM patients and it might play an important role in its pathophysiology.