Evaluation of Bone Mineral Density, Serum Osteocalcin, and Osteopontin Levels in Postmenopausal Women with Type 2 Diabetes Mellitus, with/without Osteoporosis

Correlation of metabolic markers and OPG gene mutations with bone mass abnormalities in postmenopausal women

OBJECTIVE

The aim was to investigate the relationship between metabolic indices and abnormal bone mass (ABM), analyse the association between osteoprotegerin (OPG) gene mutations and ABM, and explore the interaction effect of type 2 diabetes mellitus (T2DM) and OPG gene mutations on bone mineral density (BMD) in postmenopausal women to provide a new supplementary index and a reliable basis for the early identification of osteoporosis (OP) in postmenopausal women in the clinical setting.

METHODS

Postmenopausal women hospitalized within the Department of Endocrinology of the First Affiliated Sanatorium of Shihezi University from June 2021 to March 2023 were retrospectively analysed, and the bone mineral density of lumbar vertebrae 1-4 (BMD (L1-4)) of the studied subjects was measured once via twin-energy X-ray absorptiometry. The studied subjects were divided into a normal bone mass (NBM) group and an ABM group according to their bone mineral density, and the general data of the studied subjects were recorded once. Blood biochemical indices were determined, and genotyping of the rs4355801 locus of the OPG gene was performed. Differences in the overall data and biochemical indices of the two groups were evaluated via the rank-sum test, and the relationship between blood glucose levels and mutations of the rs4355801 locus of the OPG gene and ABM or BMD (L1-4) was evaluated via binary logistic regression analysis or linear regression analysis. A bootstrap test was performed to test whether uric acid (UA) levels mediate the association between blood glucose levels and BMD (L1-4). Simple effect analysis was performed to analyse the interaction between T2DM and mutations at the rs4355801 locus of the OPG gene on BMD (L1-4).

RESULTS

① After adjusting for confounding factors, the risk of ABM increased by 50% (95% CI 21-85%) for each unit increase in fasting plasma glucose (FPG) levels and 31% (95% CI 2-69%) for each unit increase in glycosylated haemoglobin (HbA1c) levels (both P < 0.05). FPG levels were negatively correlated with BMD (L1-4) (both P < 0.05), and uric acid in blood sugar and BMD (L1-4) played a significant mediating role in the model; this mediation accounted for 21% of the variance. ② After adjusting for confounding factors, women with the mutant genotypes GA and GG + GA of the OPG gene rs4355801 locus had a lower risk of ABM than did those with the wild-type genotype AA (OR = 0.71, 95% CI = 0.52-1.00; OR = 0.51, 95% CI = 0.28-0.92, P < 0.05). The mutant genotypes GG, GA and GG + GA were positively correlated with BMD (L1-4) (all P < 0.05). The interaction between T2DM and mutations in the OPG gene rs4355801 locus had an effect on BMD (L1-4), and this site mutation weakened the increase in blood glucose levels and led to an increase in the risk of ABM (P < 0.05).

CONCLUSION

Elevated blood glucose levels in postmenopausal women were associated with an increased risk of ABM, and UA played a mediating role in the relationship FPG levels and BMD (L1-4), accounting for 21% of the variance. Mutations at the rs4355801 locus of the OPG gene were associated with a reduced risk of ABM in postmenopausal women. The interaction between T2DM and mutations at the rs4355801 locus of the OPG gene in postmenopausal women affects BMD (L1-4), and mutations at this locus attenuate the increased risk of ABM due to elevated blood glucose levels.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND

The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years, which also may lead to some complications such as alveolar bone resorption or tooth root resorption. Low-intensity pulsed ultrasound (LIPUS), a noninvasive physical therapy, has been shown to promote bone fracture healing. It is also reported that LIPUS could reduce the duration of orthodontic treatment; however, how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.

AIM

To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement (OTM) model and explore the underlying mechanisms.

METHODS

A rat model of OTM was established, and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction, Western blot, alkaline phosphatase (ALP) staining, and Alizarin red staining. The expression of Yes-associated protein (YAP1), the actin cytoskeleton, and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA (siRNA) application via immunofluorescence.

RESULTS

The force treatment inhibited the osteogenic differentiation potential of hBMSCs; moreover, the expression of osteogenesis markers, such as type 1 collagen (COL1), runt-related transcription factor 2, ALP, and osteocalcin (OCN), decreased. LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force. Mechanically, the expression of LaminA/C, F-actin, and YAP1 was downregulated after force treatment, which could be rescued by LIPUS. Moreover, the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment. Consistently, LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo. The decreased expression of COL1, OCN, and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.

CONCLUSION

LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis, which may be a promising strategy to reduce the orthodontic treatment process.

The impact of diabetes, anemia, and renal function in the relationship between osteoporosis and fasting blood glucose among Taiwanese women: a cross-sectional study

BACKGROUND

The aim of this study was to investigate the association between fasting blood glucose and osteoporosis in women with diabetes, anemia, and renal function.

METHODS

The medical records of women who underwent a general health examination at a regional hospital in southern Taiwan were retrospectively reviewed. Logistic regression analysis was performed to assess the association between osteoporosis and fasting blood glucose separately for the eight subgroups (diabetes or non-diabetes, anemia or non-anemia, normal or decreased renal function), adjusting for other clinical characteristics and laboratory findings.

RESULTS

A total of 11,872 women were included in the study. Among women with diabetes, anemia, and decreased renal function, an increment of 10 mg/dL in fasting blood glucose was associated with an increased risk of osteoporosis (adjusted odds ratio [aOR] = 1.57, p = 0.004). Among women without diabetes, fasting blood glucose was significantly associated with an increased risk of osteoporosis in those with anemia and normal renal function (OR = 1.14, p = 0.023) and those without anemia and normal renal function (OR = 1.04, p = 0.015), but these associations were not significant after adjusting for other covariates.

CONCLUSIONS

Higher fasting blood glucose levels in women with diabetes, anemia, and decreased renal function were associated with an increased risk of osteoporosis. Clinicians should be vigilant about glucose control in patients with diabetes to reduce the risk of fracture.