title: Circulating dipeptidyl peptidase-4 activity is associated with insulin resistance in type 1 diabetic patients.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  Serum DPP4 activity is associated with IR in T1DM patients and it might play an important role in its pathophysiology.
authors: Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, School of Medicine Zagreb, Croatia. Electronic address: kblaslov@gmail.com.
authors: K
authors: K
authors: Blaslov
authors: Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, School of Medicine Zagreb, Croatia.
authors: T
authors: T
authors: Bulum
authors: Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, School of Medicine Zagreb, Croatia.
authors: L
authors: L
authors: Duvnjak
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000453:epidemiology / Q000378:metabolism*; D018819:Dipeptidyl Peptidase 4 / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D018819:Dipeptidyl Peptidase 4
keywords: Adipokines; Dipeptidyl peptidase-4; Insulin resistance; Renal function; Type 1 diabetes