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

Inhibition of dipeptidyl peptidase IV protects tacrolimus-induced kidney injury

“…It is well known that DPP IV activity is associated with insulin resistance in Types 1 and 2 diabetic patients, and it might have an important role in its pathophysiology. 31 In addition, several reports proposed that hypoxia may upregulate DPP IV activity, and it was detected as a novel target gene of the hypoxia-induced factor-1. 32,33 Others revealed that the exogenous administration of TGFβ1, which is a well-known central player in renal fibrosis, markedly enhanced DPP IV activity in proximal tubules cells.…”

Dipeptidyl peptidase-4 activity is associated with urine albumin excretion in type 1 diabetes

“…Data on serum creatinine levels, age, sex and race were used to calculate the estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, which was shown to be accurate in determining renal function in diabetic patients with normal renal function [18,19] . spectrophotometrically as previously described [20]. One unit of activity was defined as the amount of enzyme which will hydrolise the DPP-4 substrate to yield 1.0 μmol of AMC per minute at 37 °C.…”

Dipeptidyl peptidase-4 activity might be a link between tumour necrosis factor alpha and insulin resistance in type 1 diabetes

“…In this assay, DPP4 cleaves H-Gly-Pro-AMC to release a fluorescent product, 7-Amino-4-Methyl Coumarin (AMC) which can be measured spectrophotometrically as previously described [9]. One unit of activity was defined as the amount of enzyme which will hydrolise the DPP-4 substrate to yield 1.0 μmol of AMC per minute at 37 °C.…”

“…A fraction of soluble DPP-4 originates from the immune system cells which explains its altered abundance and the circulating activity in various immune mediated conditions [6] including T1DM [7]. Recent data suggest that DPP-4 activity is higher in patients with T1DM compared to healthy controls independently of islet-cell antibody status, C-peptide concentration, disease duration or glycated hemoglobin (HbA1c) level [8] and in an inverse correlation with body mass index (BMI) and insulin sensitivity [8,9]. TNF α is closely related to metabolic disorders and diabetes.…”

“…However, our recent finding that DPP-4 activity might link adiposity to IR in T1DM patients [9] and the fact that DPP-4 activity is partially modulated by TNF α [15] leads to the speculation that TNF α might modulate insulin sensitivity via DPP-4 activity. Thus, with respect to the relationship between TNF α to IR and glycaemic control in T2DM, as well as its involvement in the β cell apoptosis in T1DM, it was the aim of our study to investigate the association of TNF α plasma concentrations in conjunction with serum DPP-4 activity with IR in cohort of T1DM patients.…”