Endocrine Abstracts

Introduction: Diabetes mellitus (DM) is a chronic disease associated with multi-organ complications, including poor bone quality and high risk of frailty fracture. Bone and vascular complications seemed to be connected, as diabetic patients with atherosclerotic lesions show enhanced extrascheletric calcifications which in turn are associated with increased fracture risk. The aim of this study was to assessed bone mineral density (BMD) and trabecular bone score (TBS) in diabetic post-menopausal women and healthy controls, and correlate them with aortic calcifications, markers of bone turn-over, glucose metabolism and myeloid calcifying cells (MCCs).

Materials and methods: 23 diabetic post-menopausal women and 25 healthy female subjects matched by age were recruited; all subjects underwent a blood exam for glucose, lipid and bone metabolism profile. MCCs were measured using flow cytometry based on the expression of osteocalcin (OC) and bone alkaline phosphatase (BAP) on monocytes and circulating CD34+ stem cells. Abdominal aortic calcifications were evaluated using Kauppila score.

Results: Bone turn-over markes (β-cross laps, BAP, OC and procollagen I N-terminal) were lower in diabetic group, and were inversely correlated with glycemia and HbA1c. We found differences in lumbar Z-score, total femur BMD, total femur T-score that were lower in the controls (−0.02±1.2 vs 0.735±1.4, P=0.048; 0.820±0.1 vs 0.902±0−1, P=0.010 and 1.004±0.9 vs 0.330±0.9, P=0.011). A direct correlation was found between BMI and total BMD (r=0.519, P<0.001) and total T score (r=0.523, P<0.001). On the contrary, BMI was negatively correlated with TBS (r=−0.495, P<0.001). TBS was significantly lower in diabetic women (1.18±0.2 vs 1.26±0.1, P=0.037). DM-patients presented lower magnesium levels than controls (0.78±0.1 vs 0.84±0.1, P=0.012) and it was linked with total cholesterol (r=0.355, P=0.014) and HDL (r=0.378, P=0.009). MCCs levels did not differ among the two groups of patients and were related with BAP levels. Kauppila score was higher in the diabetic group (4.2±4.8 vs 2±2.7, P=0.052) and it was directly correlated to glycemia (r=0.310, P=0.032) and HbA1c (r=0.315, P 0.029). This score was directed correlated to the percentage of OC+ BAP+/CD34+ cells (r=0.304, P=0.036).

Conclusion: Our preliminary data confirmed that the function of bone tissue is not limited to body support and organ protection; in fact, it plays a pivotal role in regulating both glucose metabolism and cardiovascular complications development in type 2 DM, being at the same time a cofactor and a target of diabetic complications.