Inverse relationship between serum adenosine deaminase levels and islet beta cell function in patients with type 2 diabetes

OBJECTIVE: Type 2 diabetes (T2D) is a chronic low-grade inflammatory disease, which characterized by islet beta cell dysfunction. Serum adenosine deaminase (ADA) is an important enzyme that regulates the biological activity of insulin, and its levels are greatly increased in inflammatory diseases with insulin resistance. The present study was designed to explore the relationship between serum ADA levels and islet beta cell function in patients with T2D. METHODS: This cross-sectional study recruited 1573 patients with T2D from the Endocrinology Department of the Affiliated Hospital 2 of Nantong University between 2015 and 2018. All participants were received serum ADA test and oral glucose tolerance test (OGTT). Insulin sensitivity index (assessed by Matsuda index using C-peptide, ISI(M-cp)), insulin secretion index (assessed by ratio of area under the C-peptide curve to glucose curve, AUC(cp/glu)) and islet beta cell function (assessed by insulin secretion-sensitivity index 2 using C-peptide, ISSI2(cp)) were derived from OGTT. And other clinical parameters, such as HbA1c, were also collected. RESULTS: It was showed that HbA1c was significantly increased, while ISI(M-cp), AUC(cp/glu) and ISSI2(cp) significantly decreased, across ascending quartiles of serum ADA levels. Moreover, serum ADA levels were negatively correlated with ISSI2(cp) (r = − 0.267, p < 0.001). Furthermore, after adjusting for other clinical parameters by multiple linear regression analysis, serum ADA levels were still independently associated with ISSI2(cp) (β = − 0.125, t = − 5.397, p < 0.001, adjusted R(2) = 0.459). CONCLUSIONS: Serum ADA levels are independently associated with islet beta cell function in patients with T2D.