Role of plasma osteocalcin levels in blood glucose concentrations and insulin levels in type II diabetic Sudanese patients

Abstract

Abstract BACKGROUND: Osteocalcin, a bone-derived protein, has recently been reported to affect energy metabolism. This study aimed to evaluate the role of osteocalcin levels in blood glucose concentrations and insulin levels in newly diagnosed type II diabetic Sudanese patients. OBJECTIVES: Compare the differences in fasting blood glucose (FBG) concentration, fasting plasma insulin (FPI) level and lipid profile between newly diagnosed type II diabetic Sudanese patients and healthy controls, and whether these differences are affected by gender, age and body mass index (BMI). Compare the differences in total osteocalcin (TOC), undercarboxylated osteocalcin (ucOC) concentrations between newly diagnosed type II diabetics and controls, and whether the differences are affected by age, gender and BMI. Determine the correlation of age, gender, BMI with TOC, ucOC. MATERIALS & METHODS : 115 subjects, who were referred for diagnosis of diabetes mellitus in Khartoum state for the first time, were included in this study. 65 normal subjects were randomly selected from the same area as a control. 5 ml of venous blood was withdrawn from all participants after an overnight fasting, and was immediately centrifuged to separate the plasma. The plasma was used to measure the levels of TOC, ucOC and FPI, by enzyme-linked immunosorbent assay (ELISA), while FBG and lipid profile were measured by automated blood chemistry analyzer. Univariate analysis was used to determine correlation between diabetes, gender, age, BMI, with TOC, ucOC, FI, FBG and lipid profile.vii RESULTS: In spite of presence of interactions between status (diabetic or not) and gender, status and age, status and BMI affecting the results of TOC, ucOC, FPI, FBG and lipid profile, but all these interactions were not statistically significant (P > 0.05 for all). The mean of plasma concentration of TOC was significantly less in newly diagnosed diabetic group (2.38 ± 1.39 ng/ml) compared to control one (14.83 ± 2.11 ng/ml) (P = 0.000). The mean of ucOC concentration was significantly higher in the controls (2.61 ± 0.49 ng/ml) compared to the diabetics (1.09 ± 0.57 ng/ml) (P = 0.000). The mean of plasma FI concentration was higher in diabetics (20 ± 6 U/L) compared to control one (9 ± 2 U/L) (P = 0.000). The mean of plasma FBG concentration was higher in diabetics (195 ± 59 mg/dl) compared to control one (85 ± 25 mg/dl) (P = 0.000). The mean of plasma total cholesterol (TCHOL) concentration was significantly higher in diabetics (160 ± 35 mg/dl) compared to controls (147 ± 22 mg/dl) (P = 0.003), while the mean of plasma high density lipoprotein (HDL) concentration was significantly lesser in diabetics (20 ± 6 mg/dl) compared to controls (33 ± 6 mg/dl) (P = 0.000). There were statistically significant correlations for TOC and ucOC with FBG and FPI (P = 0.000 for all Spearman correlation). There were statistically significant correlations for TOC with TCHOL and HDL that is statistically significant (P= 0.003, 0.05 respectively), but the correlation for triglycerides (TG) and low density lipoprotein (LDL) were not statistically significant (P > 0.05). CONCULSION: In conclusion, osteocalcin may have an important role in glucose metabolism, probably through enhancing insulin secretion and improving insulin resistance. Osteocalcin may also play an important role in lipid metabolism in type 2 diabetes mellitus (T2DM) patients. KEY WORDS: Total Osteocalcin, Undercarboxylated Osteocalcin, Fasting Insulin, Fasting Blood Glucose Lipid profile and Type II diabetes mellitus.viii