Association between osteocalcin, a pivotal marker of bone metabolism, and secretory function of islet beta cells and alpha cells in Chinese patients with type 2 diabetes mellitus: an observational study

• Published in: Diabetology and metabolic syndrome 2022-10, Vol.14 (1), p.1-160, Article 160
• Main Authors: Lei, Haiyan, Liu, Jun, Wang, Wei, Yang, Xinyi, Feng, Zhouqin, Zang, Pu, Lu, Bin, Shao, Jiaqing
• Format: Article
• Language: English
• Subjects: Alanine transaminase; Analysis; Beta cells; Blood glucose; Blood sugar; Body fat; Body mass index; Bone turnover; Cell growth; Correlation analysis; Diabetes; Diabetes mellitus (non-insulin dependent); Diabetic retinopathy; Disease; Drugs; Gene expression; Glucagon; Glucagon secretion; Glucose; Glucose metabolism; Hemoglobin; Homeostasis; Hormones; Immunoassay; Insulin; Insulin resistance; Metabolism; Multiple regression analysis; Observational studies; Osteocalcin; Pancreas; Pancreatic beta cells; Pancreatic secretion; Peptides; Physiological aspects; Plasma; Secretion; Serum osteocalcin; Type 2 diabetes; Type 2 diabetes mellitus; Womens health
• ISSN: 1758-5996; 1758-5996
• DOI: 10.1186/s13098-022-00932-8

Background Several recent studies have found that Osteocalcin (OCN), a multifunctional protein secreted exclusively by osteoblasts, is beneficial to glucose metabolism and type 2 diabetes mellitus (T2DM). However, the effects of OCN on islets function especially islet É cells function in patients with type 2 diabetes mellitus characterized by a bi-hormonal disease are still unclear. The purpose of this cross-sectional study was to investigate the relationship between serum OCN and the secretion of islet [beta] cells and É cells in Chinese patients with type 2 diabetes mellitus. Methods 204 patients with T2DM were enrolled. Blood glucose (FBG, PBG0.5h, PBG1h, PBG2h, PBG3h), insulin (FINS, INS0.5h, INS1h, INS2h, INS3h), C-peptide (FCP, CP0.5h, CP1h, CP2h, CP3h), and glucagon (GLA0, GLA0.5 h, GLA1h, GLA2h, GLA3h) levels were measured on 0 h, 0.5 h, 1 h, 2 h, and 3 h after a 100 g standard bread meal load. Early postprandial secretion function of islet [beta] cells was calculated as [DELA]cp0.5h = CP0.5-FCP. The patients were divided into low, medium and high groups (T1, T2 and T3) according to tertiles of OCN. Comparison of parameters among three groups was studied. Correlation analysis confirmed the relationship between OCN and pancreatic secretion. Multiple regression analysis showed independent contributors to pancreatic secretion. Main results FBG, and PBG2h were the lowest while [DELA]cp0.5h was the highest in the highest tertile group (respectively, p < 0.05). INS3h, area under the curve of insulin (AUC.sub.ins3h) in T3 Group were significantly lower than T1 Group (respectively, p < 0.05). GLA1h in T3 group was lower than T1 group (p < 0.05), and GLA0.5 h in T3 group was lower than T2 and T1 groups (p < 0.05). Correlation analysis showed OCN was inversely correlated with Homeostatic model of insulin resistance (HOMA-IR), INS3h, AUC.sub.ins3h (p < 0.05), and was still inversely correlated with FCP, GLA0.5 h, GLA1h, area under the curve of glucagon (AUC.sub.gla3h) (respectively, p < 0.05) after adjustment for body mass index (BMI) and alanine aminotransferase (ALT). The multiple regression analysis showed that OCN was independent contributor to [DELA]cp0.5h, GLA0.5h and GLA1h (respectively, p < 0.05). Conclusions Higher serum OCN level is closely related to better blood glucose control, higher insulin sensitivity, increased early-phase insulin secretion of islet [beta] cells and appropriate inhibition of postprandial glucagon secretion of islet É cells in