Impaired Glucose-Stimulated Proinsulin Secretion Is an Early Marker of b-Cell Impairment Before Prediabetes Stage

• Published in: The journal of clinical endocrinology and metabolism 2019-10, Vol.104 (10), p.4341
• Main Authors: Yang, Ying, Wang, Min, Tong, Jingzhi, Dong, Zuoliang, Deng, Min, Ren, Xiaojun, Li, Hui, Yang, Jing, Meng, Zhaowei, Sun, Jinhong, He, Qing, Liu, Ming
• Format: Article
• Language: English
• Subjects: B cells; Dextrose; Evaluation; Glucose; Insulin; Insulin resistance; Prediabetic state
• ISSN: 0021-972X
• DOI: 10.1210/jc.2019-00549

ORCiD numbers: 0000-0003-2665-4072 (M. Liu). Context: Evidence indicates that there is substantial impairment/loss of b-cell function/mass even before prediabetes. Elevated plasma proinsulin is a sign of b-cell dysfunction in patients with diabetes/prediabetes. However, the dynamic changes of glucose stimulated proinsulin secretion (GSPS) among nondiabetic individuals remain obscure. Objective: To examine GSPS and glucose-stimulated insulin secretion (GSIS) among individuals with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) and to evaluate whether impaired GSPS is an early biomarker of b-cell impairment in individuals with NGT who have subthreshold postprandial plasma glucose (PPG). Design and Participants: We evaluated GSPS and GSIS in 116 Chinese adults without diabetes (mean age [+ or -] SD, 33.31 [+ or -] 9.10 years; mean BMI, 25.24 [+ or -] 4.20 kg/[m.sup.2]) with fasting plasma glucose (FPG) < 5.6 mmol/L. Based on 2hPPG, the participants were divided into three groups: NG[T.sub.1] (2hPPG < 6.67 mmol/L), NG[T.sub.2] (6.67 [less than or equal to] 2hPPG < 7.78 mmol/L), and IGT (7.78 [less than or equal to] 2hPPG