Diabetes mellitus and bone health: epidemiology, etiology and implications for fracture risk stratification

Diabetes disrupts osteometric and trabecular morphometric parameters in the Zucker Diabetic Sprague-Dawley rat femur

Type 2 diabetes mellitus is increasingly becoming more prevalent worldwide together with hospital care costs from secondary complications such as bone fractures. Femoral fracture risk is higher in diabetes. Therefore, this study aimed to assess the osteometric and microarchitecture of the femur of Zucker Diabetic Sprague-Dawley (ZDSD) femur. Ten-week-old male rats (n=38) consisting of 16 control Sprague-Dawley (SD) and 22 ZDSD rats were used. The rats were terminated at 20 weeks and others at 28 weeks of age to assess age, diabetes duration effects and its severity. Bilateral femora were taken for osteometry, bone mass measurements and micro-focus X-ray computed tomography scanning to assess the trabecular number (TbN), thickness (TbTh), spaces (TbSp), bone tissue volume to total volume (BV/TV) and volume (BV). Diabetic rats had shorter (except for 20-weeks-old), lighter, narrower, and less robust bones than SD controls that wered more robust. Although cortical area was similar in all diabatic and control rats, medullary canal area was the largest in ZDSD rats. This means that the diabetic rats bones were short, light and hollow. Diabetic rats aged 20 weeks had reduced BV, BV/TV, TbN with more spacing (TbSp). In contrast, the 28 weeks old diabetic rats only showed reduced BV and TbN. Discriminant function analysis revealed, for the first time, that osteometric parameters and TbTh, TbN, and TbSp were affected by diabetes. This knowledge is valuable in the management of diabetic complications.

Synergistic effects of Metformin and Forskolin on oxidative stress induced by diabetes and hepatocellular cancer: An animal study

AIM

This study proposed to assess the synergistic effects of Forskolin and Metformin (alone and in combination) on glucose, hematological, liver serum, and oxidative stress parameters in diabetic, healthy, and hepatocellular carcinoma (HCC) induced rats.

MATERIALS AND METHODS

Eighty male Wistar rats were divided into 10 experimental groups (8 rats for each group), including 1) healthy group, 2) diabetic group, 3) HCC group, 4) diabet + Metformin (300 mg/kg), 5) diabet + Forskolin (100 mg/kg), 6) diabet + Metformin (300 mg/kg) & Forskolin (100 mg/kg), 7) HCC + Metformin (300 mg/kg), 8) HCC + Forskolin (100 mg/kg), 9) HCC + Metformin (300 mg/kg) & Forskolin (100 mg/kg), and 10) healthy group + Metformin (300 mg/kg) & Forskolin (100 mg/kg). The rats were administrated Forskolin/Metformin daily for 8 weeks. Glucose, hematological, and liver serum parameters were measured and compared among the groups. The levels of malondialdehyde (MDA), and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), as well as 8-hydroxydeoxyguanosine (8 OHdG) levels, were also measured.

RESULTS

The average blood glucose reduction in diabetic rats with the Forskolin, Metformin, and Forskolin + Metformin treatments was 43.5%, 47.1%, and 53.9%, respectively. These reduction values for HCC rats after the treatments were 21.0%, 16.2%, and 23.7%, respectively. For all the diabetic and HCC rats treated with Forskolin/Metformin, the MDA, SOD, and GPx levels showed significant improvement compared with the diabetic and HCC groups (P < 0.05). Although the rats treated with Forskolin + Metformin experienced a higher reduction in oxidative stress of blood and urine samples compared to the Forskolin group, the differences between this group and rats treated with Metformin were not significant for all parameters.

CONCLUSION

Metformin and Forskolin reduced oxidative stress in diabetic and HCC-induced rats. The results indicated that the combination of agents (Metformin & Forskolin) had greater therapeutic effects than Forskolin alone in reducing glucose levels in diabetic rats. However, the ameliorative effects of combining Metformin and Forskolin on blood and urine oxidative stress were not statistically higher than those of Metformin alone.

Short- and long-term exposure to high glucose induces unique transcriptional changes in osteoblasts in vitro

Bone is increasingly recognized as a target for diabetic complications. In order to evaluate the direct effects of high glucose on bone, we investigated the global transcriptional changes induced by hyperglycemia in osteoblasts in vitro. Rat bone marrow-derived mesenchymal stromal cells were differentiated into osteoblasts for 10 days, and prior to analysis, they were exposed to hyperglycemia (25 mM) for the short-term (1 or 3 days) or long-term (10 days). Genes and pathways regulated by hyperglycemia were identified using mRNA sequencing and verified with qPCR. Genes upregulated by 1-day hyperglycemia were, for example, related to extracellular matrix organization, collagen synthesis and bone formation. This stimulatory effect was attenuated by 3 days. Long-term exposure impaired osteoblast viability, and downregulated, for example, extracellular matrix organization and lysosomal pathways, and increased intracellular oxidative stress. Interestingly, transcriptional changes by different exposure times were mostly unique and only 89 common genes responding to glucose were identified. In conclusion, short-term hyperglycemia had a stimulatory effect on osteoblasts and bone formation, whereas long-term hyperglycemia had a negative effect on intracellular redox balance, osteoblast viability and function.

Prevalence of Diabetes Mellitus and Clinical Differences in Patients with Severe Osteoporosis and Fragility Fractures

Background: Diabetes mellitus (DM) and osteoporosis are two of the most widespread metabolic diseases in the world. The aim of this study is to investigate the prevalence of DM among patients affected by osteoporosis and fragility fractures, and to search for differences in clinical characteristics. Methods: This is a single-center retrospective, case-controlled study. A total of 589 patients attending CTO Bone Unit between 2 January 2010 and 31 May 2023, due to osteoporosis and fragility fractures, were divided into two groups, according to the diagnosis of DM. The clinical and bone characteristics of patients were compared. Results: Prevalence of DM was 12.7%. Compared to patients without DM, the median age at the time of first fracture was similar: 72 years ± 13.5 interquartile range (IQR) vs. 71 years ± 12 IQR; prevalence of combination of vertebral and hip fractures was higher (p = 0.008), as well as prevalence of males (p = 0.016). Bone mineral density (BMD) at all sites was higher in DM group; trabecular bone score (TBS), instead, was significantly lower (p < 0.001). Conclusions: Patients with fragility fractures and DM more frequently show combination of major fractures with higher BMD levels. In these patients, TBS could be a better indicator of bone health than BMD and, therefore, might be used as a diagnostic tool in clinical practice.

Alkaline Water Mitigates Bone Loss in Streptozotocin-Induced Type II Diabetic Rats

Background A decline in bone mineral density is a defining feature of osteoporosis, which is a prevalent bone complication associated with diabetes. This study aims to shed light on the protective effect of Zamzam water (ZW), a famous alkaline water, on diabetes-induced osteoporosis. Methodology Of a total of 40 male rats, 10 male rats each were divided into the following four groups: group I (normal control rats), group II (ZW group), group III (diabetic rats), and group IV (DM + ZW). Anteroposterior and lateral X-rays were taken of the rats in each group before the end of the experiment. The study assessed serum levels of inflammatory markers including interleukin 6, interleukin-1 beta, and tumor necrosis factor-alpha; bone formation markers including osteocalcin (OC); alkaline phosphatase (ALP); and bone resorption markers including the N-terminal telopeptide of collagen type I (NTX-1), bone deoxypyridinoline (DPD), and tartrate-resistant acid phosphatase 5b (TRAP-5b). Results Rats with diabetes who consumed ZW exhibited a significant (p < 0.001) increase in OC and ALP bone formation markers and a decrease in NTX-1, DPD, and TRAP-5b bone resorption markers, with improvements in the X-ray image of the vertebral column at the L6 vertebra level. Conclusions ZW improved diabetes-induced osteoporosis in rats by enhancing osteoblastic activity and downregulating osteoclastic activity.

Lower microhardness along with less heterogeneous mineralization in the femoral neck of individuals with type 2 diabetes mellitus indicates higher fracture risk

There is still limited understanding of the microstructural reasons for the higher susceptibility to fractures in individuals with type 2 diabetes mellitus (T2DM). In this study, we examined bone mineralization, osteocyte lacunar parameters, and microhardness of the femoral neck trabeculae in 18 individuals with T2DM who sustained low-energy fracture (T2DMFx: 78 ± 7 years, 15 women and 3 men) and 20 controls (74 ± 7 years, 16 women and 4 men). Femoral necks of the T2DMFx subjects were obtained at a tertiary orthopedic hospital, while those of the controls were collected at autopsy. T2DMFx individuals had lower trabecular microhardness (P = .023) and mineralization heterogeneity (P = .001), and a tendency to a lower bone area with mineralization above 95th percentile (P = .058) than the controls. There were no significant intergroup differences in the numbers of osteocyte lacunae per bone area, mineralized lacunae per bone area, and total lacunae per bone area (each P > .05). After dividing the T2DMFx group based on the presence of vascular complications (VD) to T2DMFxVD (VD present) and T2DMFxNVD (VD absent), we observed that microhardness was particularly reduced in the T2DMFxVD group (vs. control group, P = .02), while mineralization heterogeneity was significantly reduced in both T2DMFx subgroups (T2DMFxNVD vs. control, P = .002; T2DMFxVD vs. control, P = .038). The observed changes in mineralization and microhardness may contribute to the increased hip fracture susceptibility in individuals with T2DM.

The synergistic effect of diabetes mellitus and osteoporosis on the all-cause mortality: a cohort study of an American population

Background

The increasing incidence of diabetes mellitus (DM) and osteoporosis have different effects on prognosis. The two often co-occur, so we aimed to investigate whether DM and osteoporosis have an effect on all-cause death and whether DM and osteoporosis have a synergistic effect.

Methods

This study analyzed 18,658 subjects from five cycles of the National Health and Nutrition Examination Survey (NHANES). The primary endpoint was all-cause death. The subjects were divided into four groups based on the presence or absence of DM and osteoporosis. Survival curves and Cox regression analysis based on NHANES recommended weights were used to assess the risk of all-cause death between the diseased and non-diseased groups and to calculate additive interactions to assess whether there was a synergistic effect between diabetes and osteoporosis.

Results

The group with DM and osteoporosis had the lowest survival rate. After full adjustment for confounders, patients with DM alone had a 30% higher risk of all-cause death compared with those without DM and osteoporosis (HR: 1.30, 95%CI: 1.09-1.55). Patients with osteoporosis alone had a 67% higher risk of all-cause death (HR: 1.67, 95%CI:1.16-2.43) and patients with combined DM and osteoporosis had a 127% higher risk of all-cause death (HR:2.27, 95%CI: 1.57-3.27). There was an additive interaction between DM and osteoporosis [RERI (95%CI): 1.03(0.55-1.50)] and excess mortality risk of 38% [AP (95% CI) 0.38(0.30-0.46)].

Conclusions

There might be a synergistic effect of DM and osteoporosis on all-cause mortality, and patients with both conditions have a higher risk of death.

The association between type 2 diabetes mellitus/prediabetes status and femoral neck bone mineral density in old adults

BACKGROUND

The prevalence of both type 2 diabetes mellitus (T2DM) and osteoporosis has been increasing among older individuals, with these two health conditions often coexisting. Our aim in this study was to evaluate the association between T2DM status and bone mineral density (BMD) of the femoral neck among older adults in the United States.

METHODS

This was a retrospective analysis of the data from 5695 adults, 60-80 years of age. The data were obtained from the National Health and Nutrition Examination Survey, for the following years: 2005-2006, 2007-2008, 2009-2010, 2013-2014, and 2017-2018. Weighted multivariable regression analyses, with subgroup analyses as appropriate, were performed to identify an association between T2DM/prediabetes status and femoral BMD and mediating factors.

RESULTS

There was a significant positive association between T2DM/prediabetes status and femoral neck BMD among older women, but not men, after adjusting for body mass index (BMI). On subgroup analysis, stratified by BMI, the significant positive association was retained for T2DM women with a BMI of 25-29.9 kg/m2 (β, 0.030; 95% CI, 0.007-0.052) or ≥30 kg/m2 (β, 0.029; 95% CI, 0.007-0.05), and for prediabetes women with a BMI of 25-29.9 kg/m2 (β, 0.016; 95% CI, 0.001-0.030).

CONCLUSIONS

The association between a positive T2DM/prediabetes status and femoral neck BMD differed by sex among older individuals, with the association being further modulated by BMI. For women with a BMI of 25-29.9 kg/m2 or ≥30 kg/m2, T2DM was associated with a significantly higher femoral neck BMD, compared to the non-diabetes group.

Application of machine learning algorithms to predict osteoporosis in postmenopausal women with type 2 diabetes mellitus

PURPOSE

The screening and diagnosis of osteoporosis in patients with type 2 diabetes mellitus (T2DM) based on bone mineral density remains challenging because of the limited availability and accessibility of dual-energy X-ray absorptiometry. We aimed to develop and validate models to predict the risk of osteoporosis in postmenopausal women with T2DM based on machine learning (ML) algorithms.

METHODS

This retrospective study included 303 postmenopausal women with T2DM. To develop prediction models for osteoporosis, we applied nine ML algorithms combined with demographic, clinical, and laboratory data. The least absolute shrinkage and selection operator were used to perform feature selection. We used the bootstrap resampling technique for model training and validation. To test the performance of the models, we calculated indices including the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve, and decision curve analysis. Furthermore, we conducted fivefold cross-validation for parameter optimization and model validation. Feature importance was assessed using the SHapley additive explanation (SHAP).

RESULTS

We identified 10 independent predictors as the most valuable features. An AUROC of 0.616-1.000 was observed for nine ML algorithms. The extreme gradient boosting (XGBoost) model exhibited the best performance, outperforming conventional risk assessment tools and registering 0.993 in the training set, 0.798 in the validation set, and 0.786 in the test set for fivefold cross-validation. Using SHAP, we found that the explanatory variables contributed to the model and their relationship with osteoporosis occurrence. Furthermore, we developed a user-friendly tool for calculating the risk of osteoporosis.

CONCLUSIONS

With the integration of demographic and clinical risk factors, ML algorithms can accurately predict osteoporosis. The XGBoost model showed ideal performance. With the incorporation of these models in the clinic, patients may benefit from early osteoporosis diagnosis and treatment.

Denosumab treatment lapses, discontinuation, and off-treatment fracture risk: A retrospective study of patients with osteoporosis in a real-world clinical setting

INTRODUCTION

The purpose of this study was to retrospectively examine predictors of fracture risk when adult patients experienced a denosumab treatment lapse or discontinuation in a real-world clinic setting.

MATERIALS AND METHODS

Eligible patients were adults who had received ≥2 doses of denosumab at an academic health center in the United States. Demographics, treatment doses, reasons for missed doses, and fractures, were collected retrospectively from electronic health records, from an 8-year period (2010-2018). The number of times each patient incurred a treatment lapse, defined as ≥240 days between two doses (excluding lapse due to discontinuation, death, or transfer of care) was computed. The occurrence of denosumab discontinuation (excluding discontinuation due to death or transfer of care), whether the patient initiated alternative therapy, and the reason for each lapse and discontinuation were collected. Cox proportional hazards models assessed characteristics associated with risk of fracture and treatment discontinuation. A logistic regression model was used to determine if cumulative amount of time off medication (i.e., cumulative lapse time) was associated with a higher likelihood of incurring a fracture.

RESULTS

We included 534 patients: 95 % White, 86 % women, 33 % tobacco users, 13 % diagnosed with diabetes, median age 69 years (Interquartile Range (IQR): 62-77), and median Body Mass Index (BMI) 25 kg/m2 (IQR: 22-28). Thirty-six percent of patients incurred 250 lapses; 10 % discontinued therapy. Dental problems/procedures and logistical barriers were the most common reasons for lapses and discontinuations. Nineteen percent (n = 103) incurred a total of 190 fractures; of these, 121 were osteoporotic, 50 were vertebral. Risk of any, osteoporotic, and vertebral fractures were associated with off-treatment status (hazard ratio [HR] = 1.7, p = 0.043; HR = 2.0, p = 0.026; and HR = 4.2, p = 0.001, respectively) and older age (HR = 1.3, p = 0.015; HR = 1.5, p = 0.001; and HR = 1.8, p = 0.005, respectively). Older age was associated with higher risk of discontinuation (HR = 1.4, p = 0.022). There was a non-significant trend of a nonlinear association between incurring a fracture and cumulative lapse time (p = 0.087).

CONCLUSION

Denosumab treatment lapses are common, and off-treatment status may be associated with a higher risk of fractures. Clinical teams should proactively identify and address adverse effects and potential logistical barriers to reduce the risk of treatment lapses.

Evaluation of the risk factors for falls in the geriatric population presenting to the emergency department

BACKGROUND

We evaluated risk factors and frailty assessments to identify fall-prone geriatric patients in the emergency department (ED).

METHODS

This prospective study included 264 consecutive patients aged ≥65 years who presented to the ED. The participants were divided into those who had fallen or not. The patient groups were compared in terms of age, sex, presenting complaints (falls vs. others), comorbidities, medications, frailty assessment tools, and orthostatic hypotension (OH).

RESULTS

In total, 264 patients were included: 129 (48.8%) patients who had fallen and 135 (51.2%) who hadn't fallen. The mean ages of patients who had fallen and those who had not fallen were 80.48±8.38 and 79.42±7.94 years, respectively. In addition, 62.01% (n=80) and 51.85% (n=70) of patients were females. There were no statistically significant differences between the groups in terms of age or sex (P=0.290 and P=0.096, respectively). In total, 89.92% (n=116) of patients who had fallen had at least one chronic medical condition. There was a significant difference in the proportion of patients with OH between the groups. Frailty scores such as the Edmonton Frail Scale, Frail Non-Disabled Questionnaire, PRISMA-7 questionnaire, Identification of Seniors at Risk test, and Rockwood Clinical Frailty Scale scores were also significantly different between the groups. A higher PRISMA-7 score at admission was found to be an independent predictor of fall risk.

CONCLUSION

Falls occur more frequently in the older population and in females. In addition, the frailty assessment scores, except for the FRESH Frailty Scale, were associated with falls in geriatric patients. After elimination of non-significant variables in multivariate analysis, a high PRISMA-7 questionnaire score at admission was identified as an independent predictor of fall risk.

The Pathophysiology, Identification and Management of Fracture Risk, Sublesional Osteoporosis and Fracture among Adults with Spinal Cord Injury

BACKGROUND

The prevention of lower extremity fractures and fracture-related morbidity and mortality is a critical component of health services for adults living with chronic spinal cord injury (SCI).

METHODS

Established best practices and guideline recommendations are articulated in recent international consensus documents from the International Society of Clinical Densitometry, the Paralyzed Veterans of America Consortium for Spinal Cord Medicine and the Orthopedic Trauma Association.

RESULTS

This review is a synthesis of the aforementioned consensus documents, which highlight the pathophysiology of lower extremity bone mineral density (BMD) decline after acute SCI. The role and actions treating clinicians should take to screen, diagnose and initiate the appropriate treatment of established low bone mass/osteoporosis of the hip, distal femur or proximal tibia regions associated with moderate or high fracture risk or diagnose and manage a lower extremity fracture among adults with chronic SCI are articulated. Guidance regarding the prescription of dietary calcium, vitamin D supplements, rehabilitation interventions (passive standing, functional electrical stimulation (FES) or neuromuscular electrical stimulation (NMES)) to modify bone mass and/or anti-resorptive drug therapy (Alendronate, Denosumab, or Zoledronic Acid) is provided. In the event of lower extremity fracture, the need for timely orthopedic consultation for fracture diagnosis and interprofessional care following definitive fracture management to prevent health complications (venous thromboembolism, pressure injury, and autonomic dysreflexia) and rehabilitation interventions to return the individual to his/her pre-fracture functional abilities is emphasized.

CONCLUSIONS

Interprofessional care teams should use recent consensus publications to drive sustained practice change to mitigate fracture incidence and fracture-related morbidity and mortality among adults with chronic SCI.

Longitudinal alterations in bone morphometry, mechanical integrity and composition in Type-2 diabetes in a Zucker diabetic fatty (ZDF) rat

Individuals with Type-2 Diabetes (T2D) have an increased risk of bone fracture, without a reduction in bone mineral density. It is hypothesised that the hyperglycaemic state caused by T2D forms an excess of Advanced Glycated End-products (AGEs) in the organic matrix of bone, which are thought to stiffen the collagen network and lead to impaired mechanical properties. However, the mechanisms are not well understood. This study aimed to investigate the geometrical, structural and material properties of diabetic cortical bone during the development and progression of T2D in ZDF (fa/fa) rats at 12-, 26- and 46-weeks of age. Longitudinal bone growth was impaired as early as 12-weeks of age and by 46-weeks bone size was significantly reduced in ZDF (fa/fa) rats versus controls (fa/+). Diabetic rats had significant structural deficits, such as bending rigidity, ultimate moment and energy-to-failure measured via three-point bend testing. Tissue material properties, measured by taking bone geometry into account, were altered as the disease progressed, with significant reductions in yield and ultimate strength for ZDF (fa/fa) rats at 46-weeks. FTIR analysis on cortical bone powder demonstrated that the tissue material deficits coincided with changes in tissue composition, in ZDF (fa/fa) rats with long-term diabetes having a reduced carbonate:phosphate ratio and increased acid phosphate content when compared to age-matched controls, indicative of an altered bone turnover process. AGE accumulation, measured via fluorescent assays, was higher in the skin of ZDF (fa/fa) rats with long-term T2D, bone AGEs did not differ between strains and neither AGEs correlated with bone strength. In conclusion, bone fragility in the diabetic ZDF (fa/fa) rats likely occurs through a multifactorial mechanism influenced initially by impaired bone growth and development and proceeding to an altered bone turnover process that reduces bone quality and impairs biomechanical properties as the disease progresses.

Acarbose diminishes postprandial suppression of bone resorption in patients with type 2 diabetes

AIMS

The alpha-glucosidase inhibitor acarbose is an antidiabetic drug delaying assimilation of carbohydrates and, thus, increasing the amount of carbohydrates in the distal parts of the intestines, which in turn increases circulating levels of the gut-derived incretin hormone glucagon-like peptide 1 (GLP-1). As GLP-1 may suppress bone resorption, acarbose has been proposed to potentiate meal-induced suppression of bone resorption. We investigated the effect of acarbose treatment on postprandial bone resorption in patients with type 2 diabetes and used the GLP-1 receptor antagonist exendin(9-39)NH₂ to disclose contributory effect of acarbose-induced GLP-1 secretion.

METHODS

In a randomised, placebo-controlled, double-blind, crossover study, 15 participants with metformin-treated type 2 diabetes (2 women/13 men, age 71 (57-85 years), BMI 29.7 (23.6-34.6 kg/m²), HbA1c 48 (40-74 mmol/mol)/6.5 (5.8-11.6 %) (median and range)) were subjected to two 14-day treatment periods with acarbose and placebo, respectively, separated by a six-week wash-out period. At the end of each period, circulating bone formation and resorption markers were assessed during two randomised 4-h liquid mixed meal tests (MMT) with infusions of exendin(9-39)NH₂ and saline, respectively. Glucagon-like peptide 2 (GLP-2) was also assessed.

RESULTS

Compared to placebo, acarbose impaired the MMT-induced suppression of CTX as assessed by baseline-subtracted area under curve (P = 0.0037) and nadir of CTX (P = 0.0128). During acarbose treatment, exendin(9-39)NH₂ infusion lowered nadir of CTX compared to saline (P = 0.0344). Neither parathyroid hormone or the bone formation marker procollagen 1 intact N-terminal propeptide were affected by acarbose or GLP-1 receptor antagonism. Acarbose treatment induced a greater postprandial GLP-2 response than placebo treatment (P = 0.0479) and exendin(9-39)NH₂ infusion exacerbated this (P = 0.0002).

CONCLUSIONS

In patients with type 2 diabetes, treatment with acarbose reduced postprandial suppression of bone resorption. Acarbose-induced GLP-1 secretion may contribute to this phenomenon as the impairment was partially reversed by GLP-1 receptor antagonism. Also, acarbose-induced reductions in other factors reducing bone resorption, e.g. glucose-dependent insulinotropic polypeptide, may contribute.

Role of Advanced Glycation End-Products and Oxidative Stress in Type-2-Diabetes-Induced Bone Fragility and Implications on Fracture Risk Stratification

Type 2 diabetes (T2D) and osteoporosis (OP) are major causes of morbidity and mortality that have arelevant health and economic burden. Recent epidemiological evidence suggests that both of these disorders are often associated with each other and that T2D patients have an increased risk of fracture, making bone an additional target of diabetes. As occurs for other diabetic complications, the increased accumulation of advanced glycation end-products (AGEs) and oxidative stress represent the major mechanisms explaining bone fragility in T2D. Both of these conditions directly and indirectly (through the promotion of microvascular complications) impair the structural ductility of bone and negatively affect bone turnover, leading to impaired bone quality, rather than decreased bone density. This makes diabetes-induced bone fragility remarkably different from other forms of OP and represents a major challenge for fracture risk stratification, since either the measurement of BMD or the use of common diagnostic algorithms for OP have a poor predictive value. We review and discuss the role of AGEs and oxidative stress on the pathophysiology of bone fragility in T2D, providing some indications on how to improve fracture risk prediction in T2D patients.

Association of Body Mass Index and Fracture Risk Varied by Affected Bones in Patients with Diabetes: A Nationwide Cohort Study

BACKGROUND

Body mass index (BMI) is a risk factor for the type 2 diabetes (T2DM), and T2DM accompanies various complications, such as fractures. We investigated the effects of BMI and T2DM on fracture risk and analyzed whether the association varied with fracture locations.

METHODS

This study is a nationwide population-based cohort study that included all people with T2DM (n=2,746,078) who received the National Screening Program during 2009-2012. According to the anatomical location of the fracture, the incidence rate and hazard ratio (HR) were analyzed by dividing it into four categories: vertebra, hip, limbs, and total fracture.

RESULTS

The total fracture had higher HR in the underweight group (HR, 1.268; 95% CI, 1.228 to 1.309) and lower HR in the obese group (HR, 0.891; 95% CI, 0.882 to 0.901) and the morbidly obese group (HR, 0.873; 95% CI, 0.857 to 0.89), compared to reference (normal BMI group). Similar trends were observed for HR of vertebra fracture. The risk of hip fracture was most prominent, the risk of hip fracture increased in the underweight group (HR, 1.896; 95% CI, 1.178 to 2.021) and decreased in the obesity (HR, 0.643; 95% CI, 0.624 to 0.663) and morbidly obesity group (HR, 0.627; 95% CI, 0.591 to 0.665). Lastly, fracture risk was least affected by BMI for limbs.

CONCLUSION

In T2DM patients, underweight tends to increase fracture risk, and overweight tends to lower fracture risk, but association between BMI and fracture risk varied depending on the affected bone lesions.

Statin use in patients with type 2 diabetes has lower risk of hip fractures: A Taiwan national population-based study

AIMS

Type 2 diabetes mellitus (T2DM) frequently co-exists with osteoporosis and dyslipidemia. Statins have been commonly used in the treatment of dyslipidemia. Recent studies have indicated a therapeutic role of statins in decreasing the risk of osteoporosis and fractures, but conflicting results have been reported. This study investigated the association between statin use and hip fracture (HFx) risk among T2DM patients.

MATERIALS AND METHODS

A retrospective Taiwan population-based propensity-matched cohort study was performed using the Diabetes Mellitus Health Database from Taiwan National Health Insurance Research Database. Patients with newly diagnosed with T2DM between 2010 and 2014 were identified. Patients who previously used statins and had ever suffered HFx before the index date were excluded. HFx that occurred from 2010 to 2019 was collected to compute the cumulative rate of HFx. Hazard ratios (HRs) were calculated for the HFx risk according to the use or non-use of statins. To evaluate the dose-effect relationship of statins, sensitivity analyses were conducted.

RESULTS

After propensity score matching for age and sex, 188,588 patients were identified as statin users and non-statin users. Statin use after T2DM diagnosis was associated with a decreased HFx risk with an adjusted HR (aHR) of 0.69 (P < 0.001). A dose-effect relationship was identified. The aHRs for developing HFx were 1.29, 0.67, and 0.36 for patients who used 28-174, 175-447, and >447 cumulative defined daily doses of statins, respectively (P < 0.001).

CONCLUSIONS

Statin use in adults with T2DM showed a lower risk of HFx by demonstrating a dose-response relationship.

Diabetes Mellitus Disease Prediction Using Machine Learning Classifiers with Oversampling and Feature Augmentation

The technical improvements in healthcare sector today have given rise to many new inventions in the field of artificial intelligence. Patterns for disease identification are carried out, and the onset of prediction of many diseases is detected. Diseases include diabetes mellitus disease, fatal heart diseases, and symptomatic cancer. There are many algorithms that have played a critical role in the prediction of diseases. This paper proposes an ML based approach for diabetes mellitus disease prediction. For diabetes prediction, many ML algorithms are compared and used in the proposed work, and finally the three ML classifiers providing the highest accuracy are determined: RF, GBM, and LGBM. The accuracy of prediction is obtained using two types of datasets. They are Pima Indians dataset and a curated dataset. The ML classifiers LGBM, GB, and RF are used to build a predictive model, and the accuracy of each classifier is noted and compared. In addition to the generalized prediction mechanism, the data augmentation technique is also used, and the final accuracy of prediction is obtained for the classifiers LGBM, GB, and RF. A comparative study and demonstration between augmentation and non-augmentation are also discussed for the two datasets used in order to further improve the performance accuracy for predicting diabetes disease.

Weight change and the risk of hip fractures in patients with type 2 diabetes: a nationwide cohort study

Both weight gain and weight loss in type 2 diabetic population were associated with increased risk of hip fracture, while maintaining weight lowered the risk of hip fracture. Regarding the risk of hip fracture, we can propose active monitoring to maintain the weight of type 2 diabetes patients.

INTRODUCTION

In type 2 diabetes, patients are often asked to control their weight in order to reduce their diabetic morbidity. The American Diabetes Association recommends that diabetic patients conduct high-intensity interventions for regulating diet, physical activity, and behavior to reduce weight, followed by long-term comprehensive weight maintenance programs. Although such weight control attempts are required in diabetic patients, there are few studies on the effect of weight change on hip fracture in this population. We aim to investigate the association between body weight change and the incidence of hip fracture in subjects with type 2 diabetes using large-scale, nationwide cohort data on the Korean population.

MATERIALS AND METHODS

A total of 1,447,579 subjects (894,204 men and 553,375 women) > 40 years of age, who were diagnosed with type 2 diabetes, were enrolled in this study. Weight change within 2 years was divided into five categories: from weight loss ≥ 10% to weight gain ≥ 10%. The hazard ratios (HRs) and 95% confidence intervals for the incidence of hip fracture were analyzed, compared with the reference of the stable weight group (weight change < 5%).

RESULTS

Among 5 weight change groups, more than 10% weight loss showed the highest HR (HR, 1.605; 95% CI, 1.493 to 1.725), followed by more than 10% weight gain (HR, 1.457; 95% CI, 1.318 to 1.612). The effect of weight change on hip fracture risk was greater in males than in females, and those under 65 years of age were greater than those over 65 years of age. Baseline BMI did not play a role of weight change affecting the risk of hip fracture. The HR for hip fracture of subjects with regular exercise was lower than those without regular exercise.

CONCLUSIONS

In the type 2 diabetes population, both weight gain and weight loss were significantly associated with a higher risk of hip fracture, whereas maintaining body weight reduced the risk of hip fracture the most.

Does Serum Osteocalcin Level Affect Carotid Atherosclerosis in Post-Menopausal Diabetic Females? A Case-Control Study

Purpose

To determine the association between serum osteocalcin and carotid intima media thickness (CIMT) in a group of post-menopausal females with type 2 diabetes (T2DM).

Patients and Methods

This cross-sectional study enrolled 75 postmenopausal women with T2DM and 40 age matched postmenopausal healthy females. Age, body mass index, blood pressure were recorded for all subjects. Laboratory tests including fasting blood glucose (FBG), glycated hemoglobin (HbA1c) and lipid profile were measured. Serum osteocalcin was measured using ELISA. Bone mineral density (BMD) was measured by DEXA scan. CIMT was assessed with B-mode ultrasonography.

Results

Patients with T2DM had significantly lower serum osteocalcin compared to control (63.73±27.20 vs 136.16±21.96 pg/mL, P<0.001). Patients with osteoporosis had significantly lower osteocalcin level compared to those with normal BMD. Patients with T2DM had a significant negative correlation between serum osteocalcin and CIMT (r= -0.332; P=0.003), FBG (r= -0.732; P< 0.001), HbA1c (r=-0.672; P< 0.001), and HOMA-IR (r= -0.672; P< 0.001). However, multiple linear regression analysis revealed that CIMT in patients with diabetes was only significantly associated with age (P= 0.001), duration of diabetes (P< 0.001), SBP (P< 0.001), HOMA-IR (P=0.033), LDL (P=0.005), and HDL (P< 0.001). Furthermore, serum insulin (β= -0.183, P=0.033), FBG (β= -0.604, P< 0.001) and LDL (β= -0.195, P= 0.02) were independently negatively correlated with serum osteocalcin.

Conclusion

In this study, Postmenopausal women with diabetes had significantly lower osteocalcin compared to non-diabetic women. Although serum osteocalcin was negatively correlated with CIMT, multivariate regression analysis revealed that osteocalcin level was only independently related to worse glycemic parameters in postmenopausal women with T2DM.

Identification and Characterization of a Novel Long Noncoding RNA that Regulates Osteogenesis in Diet-Induced Obesity Mice

As a precursor to type 2 diabetes mellitus (T2D), obesity adversely alters bone cell functions, causing decreased bone quality. Currently, the mechanisms leading to alterations in bone quality in obesity and subsequently T2D are largely unclear. Emerging evidence suggests that long noncoding RNAs (lncRNAs) participate in a vast repertoire of biological processes and play essential roles in gene expression and posttranscriptional processes. Mechanistically, the expression of lncRNAs is implicated in pathogenesis surrounding the aggregation or alleviation of human diseases. To investigate the functional link between specific lncRNA and obesity-associated poor bone quality and elucidate the molecular mechanisms underlying the interaction between the two, we first assessed the structure of the bones in a diet-induced obese (DIO) mouse model. We found that bone microarchitecture markedly deteriorated in the DIO mice, mainly because of aberrant remodeling in the bone structure. The results of in vitro mechanistic experiments supported these observations. We then screened mRNAs and lncRNAs from DIO bones and functionally identified a specific lncRNA, Gm15222. Further analyses demonstrated that Gm15222 promotes osteogenesis and inhibits the expression of adipogenesis-related genes in DIO via recruitment of lysine demethylases KDM6B and KDM4B, respectively. Through this epigenetic pathway, Gm15222 modulates histone methylation of osteogenic genes. In addition, Gm15222 showed a positive correlation with the expression of a neighboring gene, BMP4. Together, the results of this study identified and provided initial characterization of Gm15222 as a critical epigenetic modifier that regulates osteogenesis and has potential roles in targeting the pathophysiology of bone disease in obesity and potential T2D.

Bone microarchitecture, bone mineral density and bone turnover in association with glycemia and insulin action in women with prior gestational diabetes

OBJECTIVE

The aim of this cross-sectional study was to comprehensively assess bone health in women with prior gestational diabetes mellitus, including bone microarchitecture (TBS), bone mineral density (BMD, DXA) and bone turnover (osteocalcin).

DESIGN, PATIENTS AND MEASUREMENTS

Study participants underwent a detailed anthropometric, biochemical and hormone assessment, including insulin and osteocalcin measurement. BMD was measured at lumbar spine, femur neck and total hip using DXA and TBS derived from lumbar spine DXA images using TBS iNsight software.

RESULTS

A total of 240 women (mean age: 33.3 ± 5.0 years; median postpartum duration: 34 [interquartile range 13.0-54.5] months were evaluated. At the current visit, 115 (47.9%) and 36 (15%) women had prediabetes and diabetes, respectively. Women with dysglycemia (diabetes/prediabetes) had a higher BMD at all three sites, compared to those with normoglycemia; however, the difference was not statistically significant. Women with dysglycemia had a significantly lower TBS (1.32 ± 0.09 vs. 1.35 ± 0.09; p = .038). In the fully adjusted model, the odds ratio for association between diabetes and low TBS was 2.92 (95% confidence interval: 1.20, 7.08; p = .018). Women with dysglycemia had significantly lower serum osteocalcin levels (18.6 ± 8.5 ng/ml vs. 21.5 ± 9.7 ng/ml; p = .018). HOMA-IR (r = -.285, p < .001) was negatively correlated, while Matsuda index (r = .274, p < .001) and disposition index (r = .159, p = .016) were positively correlated with serum osteocalcin levels.

CONCLUSIONS

Bone health is affected early in the natural history of diabetes and is associated with an overall low bone turnover state.

Disparities in osteoporosis care among postmenopausal women in the United States

Osteoporosis and fragility fractures result in significant morbidity and mortality and contribute to substantial healthcare costs. Despite being a treatable disease, osteoporosis remains both underdiagnosed and undertreated in the US general population, with significant disparities in care between non-White and White women. These disparities are evident from screening to post-fracture treatment. Non-White women are less likely to be screened for osteoporosis, to be prescribed pharmacotherapy, or to receive treatment post-fracture; furthermore, the mortality rate after fracture is higher in non-White women. Given existing diagnostic and treatment disparities, additional studies and interventions are needed to optimize the bone health of Asian, Black, Hispanic, and Native American women, and to reduce morbidity and mortality from osteoporosis and fragility fractures.

Risk Factors for Fracture in Patients with Coexisting Chronic Kidney Disease and Type 2 Diabetes: An Observational Analysis from the CREDENCE Trial

BACKGROUND

The fracture pathophysiology associated with type 2 diabetes and chronic kidney disease (CKD) is incompletely understood. We examined individual fracture predictors and prediction sets based on different pathophysiological hypotheses, testing whether any of the sets improved prediction beyond that based on traditional osteoporotic risk factors.

METHODS

Within the CREDENCE cohort with adjudicated fracture outcomes, we assessed the association of individual factors with fracture using Cox regression models. We used the Akaike information criteria (AIC) and Schwartz Bayes Criterion (SBC) to assess six separate variable sets based on hypothesized associations with fracture, namely, traditional osteoporosis, exploratory general population findings, cardiovascular risk, CKD-mineral and bone disorder, diabetic osteodystrophy, and an all-inclusive set containing all variables.

RESULTS

Fracture occurred in 135 (3.1%) participants over a median 2.35 [1.88-2.93] years. Independent fracture predictors were older age (hazard ratio [HR] 1.04, confidence interval [CI] 1.01-1.06), female sex (HR 2.49, CI 1.70-3.65), previous fracture (HR 2.30, CI 1.58-3.34), Asian race (HR 1.74, CI 1.09-2.78), vitamin D therapy requirement (HR 2.05, CI 1.31-3.21), HbA1c (HR 1.14, CI 1.00-1.32), prior cardiovascular event (HR 1.60, CI 1.10-2.33), and serum albumin (HR 0.41, CI 0.23-0.74) (lower albumin associated with greater risk). The goodness of fit of the various hypothesis sets was similar (AIC range 1870.92-1849.51, SBC range 1875.60-1948.04).

CONCLUSION

Independent predictors of fracture were identified in the CREDENCE participants with type 2 diabetes and CKD. Fracture prediction was not improved by models built on alternative pathophysiology hypotheses compared with traditional osteoporosis predictors.

Associations of Obesity Indices with Bone Mineral Densities and Risk of Osteoporosis Stratified Across Diabetic Vascular Disease in T2DM Patients

OBJECTIVE

To evaluate associations of obesity indices with bone mineral densities (BMD) and risk of osteoporosis in T2DM patients totally and stratified across presence of any diabetic cardiovascular complications.

METHODS

Cross-sectional analyses of baseline information on a cohort of 250 T2DM patients were conducted in Xiamen, China. Obesity indices included body weight, height, body mass index (BMI), waist and waist hip ratio (WHR). BMD was measured using dual-energy X-ray absorptiometry at three different sites, and osteoporosis was defined based on the minimum T-scores of BMD. Presence of any diabetic vascular complications was confirmed by checking their medical records histories.

RESULTS

Among the 250 T2DM patients, 50 (20.0%) were defined as osteoporosis. Multivariable linear regression and multivariable logistic regression analyses showed that igher obesity indices, including body weight, BMI and waist, but neither body height nor waist hip ratio, were positively associated with the minimum T-scores of BMD and had significantly decreased risk of osteoporosis. Stratified analyses across presence of any of diabetic vascular complications showed similar results for those with any of diabetic vascular complications, while no significant association between obesity indices and minimum T-scores of BMD was found for those without. Postmenopausal women (vs men) and ever drinking were significantly associated with increased risk of osteoporosis, and the adjusted odds ratios (95% CIs) were 5.165 (1.762-15.138, p = 0.003) and 3.789 (1.087-13.214, p = 0.037), respectively. None of metabolic profiles, including systolic and diastolic blood pressure, triglyceride, total cholesterol, high-density lipoprotein cholesterol, HbA1c and blood uric acid, was significantly associated with either minimum T-scores of BMD or risk of osteoporosis.

CONCLUSION

Associations of obesity indices with either BMD or risk of osteoporosis in T2DM patients varied by presence of any diabetic vascular complication and should be not interpreted as causal without considering the often-unmeasured effect modification by health status.

Ferroptosis as a Novel Therapeutic Target for Diabetes and Its Complications

The global diabetes epidemic and its complications are increasing, thereby posing a major threat to public health. A comprehensive understanding of diabetes mellitus (DM) and its complications is necessary for the development of effective treatments. Ferroptosis is a newly identified form of programmed cell death caused by the production of reactive oxygen species and an imbalance in iron homeostasis. Increasing evidence suggests that ferroptosis plays a pivotal role in the pathogenesis of diabetes and diabetes-related complications. In this review, we summarize the potential impact and regulatory mechanisms of ferroptosis on diabetes and its complications, as well as inhibitors of ferroptosis in diabetes and diabetic complications. Therefore, understanding the regulatory mechanisms of ferroptosis and developing drugs or agents that target ferroptosis may provide new treatment strategies for patients with diabetes.

Association of metformin use with fracture risk in type 2 diabetes: A systematic review and meta-analysis of observational studies

AIMS

Increasing evidence suggests that metformin can affect bone metabolism beyond its hypoglycemic effects in diabetic patients. However, the effects of metformin on fracture risk in type 2 diabetes mellitus (T2DM) patients remain unclear. A systematic review and meta-analysis were performed in this study to evaluate the association between metformin application and fracture risk in T2DM patients based on previous studies published until June 2021.

METHODS

A systematic search was performed to collect publications on metformin application in T2DM patients based on PubMed, Embase, Cochran, and Web of Science databases. Meta-analysis was performed by using a random-effects model to estimate the summary relative risks (RRs) with 95% confidence intervals (CIs). Subgroup analyses based on cohort/case-control and ethnicity and sensitivity analyses were also performed.

RESULTS

Eleven studies were included in the meta-analysis. Results demonstrated metformin use was not significantly associated with a decreased risk of fracture (RR, 0.91; 95% CI, 0.81-1.02; I^{2 =} 96.8%). Moreover, metformin use also demonstrated similar results in subgroup analyses of seven cohort studies and four case-control studies, respectively (RR, 0.90; 95% CI, 0.76-1.07; I^{2 =} 98.0%; RR, 0.96; 96% CI, 0.89-1.03; I^{2 =} 53.7%). Sensitivity analysis revealed that there was no publication bias.

CONCLUSION

There was no significant correlation between fracture risk and metformin application in T2DM patients. Due to a limited number of existing studies, further research is needed to make a definite conclusion for clinical consensus.

Metabolic syndrome and fragility fracture risk

INTRODUCTION

The prevalence of metabolic syndrome has been reported to extremely vary depending on the gender, age, and ethnicity studied. Approximately, 25% of the worldwide adult population is affected by metabolic syndrome, indicating it as a significantly important public health challenge. Likewise, fragility fracture represents an important public health issue too, and the lifetime residual risk of its occurrence has been established in 50% in women and 30% in men over 50 years of age, respectively. Dysmobility syndrome summarizes a cluster of co-existing conditions such as osteoporosis, sarcopenia, obesity. Currently, clinical research focuses essentially on the cardiovascular risks associated with metabolic syndrome. Today, it is conceivable to incorporate all these conditions under a generic "disorder of energy metabolism."

EVIDENCE ACQUISITION

Animal and human studies suggest metabolic and dysmobility syndromes negatively impact on the risk for fragility fracture, contributing to increase the associated mortality rate.

EVIDENCE SYNTHESIS

In recent years, strong correlation between type 2 diabetes, a frequent constitutive part of metabolic syndrome and fragility fracture risk has been reported, but the possible molecular mechanisms by which it can occur are still to be defined.

CONCLUSIONS

Only very few human clinical studies faced these aspects, but they lack adequate endpoints for a good clinical practice in these subjects. Much more still needs to be done before appropriate therapeutic diagnostic pathways will be available for these patients at risk of bone and even generalized fragility. Suggestions for a future overall approach by generating global risk score for these conditions are given.

Reduced bone mineral density in the first year after total pancreatectomy with islet autotransplantation (TPIAT)

BACKGROUND/OBJECTIVES

The effect of total pancreatectomy with islet autotransplantation (TPIAT) on bone mineral density (BMD) in patients with CP is unknown. We aimed to assess bone health in patients with CP after TPIAT.

METHODS

We measured BMD, BMD Z-score, and bone mineral content (BMC) for total body, lumbar spine, right and left hip in 78 patients before and after TPIAT using dual-energy X-ray absorptiometry (DXA, n = 78 pre-TPIAT, n = 65 paired pre- and 12 months post-TPIAT, n = 33 paired 12 and 18 months post-TPIAT), and tested for association with clinical history including age, smoking status, and medications using paired and two-sample t-tests, linear regression, and Fisher's exact test. Laboratory measures related to bone health were also assessed.

RESULTS

In the patients with pre-TPIAT DXA, 12% had low BMD (Z-score ≤ -2). BMD, BMD Z-score, and BMC all decreased from pre-to 12 months post-TPIAT. BMD declined by 1.7%-4.1% with the greatest change at the hips. Adjusted for change in lean and fat body mass, DXA changes remained significant for total body and hip. Serum carboxy-terminal collagen crosslinks telopeptide and alkaline phosphatase increased at 12 months post-TPIAT, suggesting possible increased bone remodeling. BMD, BMD Z-score, and BMC did not change between 12 months and 18 months in any of the four regions (p > 0.6).

CONCLUSIONS

TPIAT is associated with decreases in BMD in the body, lumbar, and hip regions of patients with CP in the first year after TPIAT but these appear to stabilize between 12 and 18 months after TPIAT.

Polypharmacy and bone fracture risk in patients with type 2 diabetes: The Fukuoka Diabetes Registry

AIMS

To prospectively investigate the association between the number of prescribed drugs and the fracture risk in patients with type 2 diabetes.

METHODS

Japanese participants with type 2 diabetes (n = 4,706; 2,755 men, 1,951 postmenopausal women; mean age, 66 years) were followed for a median of 5.3 years and grouped on the basis of the number of prescribed drugs at baseline. The main outcomes were fractures at any anatomic site and fragility fractures (fractures at hip and spine sites).

RESULTS

During follow-up, any fracture occurred in 662 participants. The overall age- and sex-adjusted fracture incidence rates per 1,000 person-years were 21.2 (0-2 drugs), 28.1 (3-5 drugs), 37.7 (6-8 drugs), and 44.0 (≥9 drugs) (p for trend < 0.001). Compared with 0-2 drugs, the multivariate-adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for fractures were 1.34 (1.07-1.68) for 3-5 drugs, 1.76 (1.37-2.26) for 6-8 drugs, and 1.71 (1.27-2.31) in ≥ 9 drugs. The multivariate-adjusted HR (95% CI) per increment in drugs was 1.05 (1.02-1.08) (p < 0.001). Similar tendencies were observed for fragility fractures.

CONCLUSIONS

A greater number of prescribed drugs is associated with an increased bone fracture risk in patients with type 2 diabetes.

Evidence of a Causal Relationship between Serum Thyroid-Stimulating Hormone and Osteoporotic Bone Fractures

OBJECTIVE

We aimed to validate the association of genome-wide association study (GWAS)-identified loci and polygenic risk score with serum thyroid-stimulating hormone (TSH) concentrations and the diagnosis of hypothyroidism. Then, the causal relationship between serum TSH and osteoporotic bone fracture risk was tested.

METHODS

A cross-sectional study was done among patients of European Caucasian ethnicity recruited in Tayside (Scotland, UK). Electronic medical records (EMRs) were used to identify patients and average serum TSH concentration and linked to genetic biobank data. Genetic associations were performed by linear and logistic regression models. One-sample Mendelian randomization (MR) was used to test causality of serum TSH on bone fracture risk.

RESULTS

Replication in 9,452 euthyroid individuals confirmed known loci previously reported. The 58 polymorphisms accounted for 11.08% of the TSH variation (p < 1e-04). TSH-GRS was directly associated with the risk of hypothyroidism with an odds ratio (OR) of 1.98 for the highest quartile compared to the first quartile (p = 2.2e-12). MR analysis of 5,599 individuals showed that compared with those in the lowest tertile of the TSH-GRS, men in the highest tertile had a decreased risk of osteoporotic bone fracture (OR = 0.59, p = 2.4e-03), while no difference in a similar comparison was observed in women (OR = 0.93, p = 0.61). Sensitivity analysis yielded similar results.

CONCLUSIONS

EMRs linked to genomic data in large populations allow replication of GWAS discoveries without additional genotyping costs. This study suggests that genetically raised serum TSH concentrations are causally associated with decreased bone fracture risk in men.

Effect of vitamin D supplementation on OPG/RANKL signalling activities in endothelial tissue damage in diet-induced diabetic rat model

BACKGROUND

Type 2 Diabetes Mellitus is a chronic metabolic disease that causes endothelial damage and is an important risk factor for atherosclerosis. In the present study vitamin D3 supplementation in rats was used to determine the role of Osteoprotegerin (OPG)/Receptor activator kB ligand (RANKL) signalling in endothelial damage and changes in the expression levels of genes involved in this pathway. We hypothesized that vitamin D3 supplementation affects OPG and RANKL activity in the aorta.

METHODS

Diabetes was induced in rats via injections of 40 mg/kg of streptozotocin followed by a high fructose (10%) diet. Group 2 (healthy) and 4 (diabetic) received 170 IU/kg of vitamin D3 weekly for 5 weeks, while Group 1 (healthy) and 2 (diabetic) received sterile saline. The aortas of each group were collected to analyse mRNA expression using the real-time PCR method and also to evaluate magnesium and calcium levels using inductively coupled plasma mass spectrometry.

RESULTS

Opg and Il-1b expression levels were significantly associated with both diabetes and vitamin D3 supplementation in the aortas of the study groups (p ≤ 0.05). Opg mRNA expression was also found to correlate with both Icam-1 and Nos3 mRNA expression levels (r = 0.699, p = 0.001 and r = 0.622, p = 0.003, respectively). In addition, when mineral levels in the aortic tissues were compared among all groups, it was found that the interaction of diabetes and vitamin D3 supplementation significantly affected Mg levels and Mg/Ca ratios.

CONCLUSIONS

It is concluded that vitamin D3 supplementation has a modulatory effect on OPG/RANKL activity in the vessel wall by ameliorating endothelial damage in diabetes. This effect may contribute to the regulation of cytokine-mediated vascular homeostasis and mineral deposition in the aorta; therefore, further comprehensive studies are proposed to demonstrate this relationship.

Effects of GLP-1 Receptor Agonists on Bone Mineral Density in Patients with Type 2 Diabetes Mellitus: A 52-Week Clinical Study

Introduction

Hypoglycemic drugs affect the bone quality and the risk of fractures in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and insulin on bone mineral density (BMD) in T2DM.

Methods

In this single-blinded study, a total of 65 patients with T2DM were randomly assigned into four groups for 52 weeks: the exenatide group (n = 19), dulaglutide group (n = 19), insulin glargine group (n = 10), and placebo (n = 17). General clinical data were collected, and BMD was measured by dual-energy X-ray absorptiometry.

Results

Compared with baseline, the glycosylated hemoglobin (HbA1c) decreased significantly in the exenatide (8.11 ± 0.24% vs. 7.40 ± 0.16%, P = 0.007), dulaglutide (8.77 ± 0.37% vs. 7.06 ± 0.28%, P < 0.001), and insulin glargine (8.57 ± 0.24% vs. 7.23 ± 0.25%, P < 0.001) groups after treatment. In the exenatide group, the BMD of the total hip increased. In the dulaglutide group, only the BMD of the femoral neck decreased (P = 0.027), but the magnitude of decrease was less than that in the placebo group; the BMD of L1-L4, femoral neck, and total hip decreased significantly (P < 0.05) in the placebo group, while in the insulin glargine group, the BMD of L2, L4, and L1-4 increased (P < 0.05). Compared with the placebo group, the BMD of the femoral neck and total hip in the exenatide group and the insulin glargine group were increased significantly (P < 0.05); compared with the exenatide group, the BMD of L4 in the insulin glargine group was also increased (P = 0.001).

Conclusions

Compared with the placebo, GLP-1RAs demonstrated an increase of BMD at multiple sites of the body after treatment, which may not exacerbate the consequences of bone fragility. Therefore, GLP-1RAs might be considered for patients with T2DM. This trial is registered with ClinicalTrials.gov NCT01648582.

Cellular senescence in musculoskeletal homeostasis, diseases, and regeneration

Emerging insights into cellular senescence highlight the relevance of senescence in musculoskeletal disorders, which represent the leading global cause of disability. Cellular senescence was initially described by Hayflick et al. in 1961 as an irreversible nondividing state in in vitro cell culture studies. We now know that cellular senescence can occur in vivo in response to various stressors as a heterogeneous and tissue-specific cell state with a secretome phenotype acquired after the initial growth arrest. In the past two decades, compelling evidence from preclinical models and human data show an accumulation of senescent cells in many components of the musculoskeletal system. Cellular senescence is therefore a defining feature of age-related musculoskeletal disorders, and targeted elimination of these cells has emerged recently as a promising therapeutic approach to ameliorate tissue damage and promote repair and regeneration of the skeleton and skeletal muscles. In this review, we summarize evidence of the role of senescent cells in the maintenance of bone homeostasis during childhood and their contribution to the pathogenesis of chronic musculoskeletal disorders, including osteoporosis, osteoarthritis, and sarcopenia. We highlight the diversity of the senescent cells in the microenvironment of bone, joint, and skeletal muscle tissue, as well as the mechanisms by which these senescent cells are involved in musculoskeletal diseases. In addition, we discuss how identifying and targeting senescent cells might positively affect pathologic progression and musculoskeletal system regeneration.

Treatment of bone fragility in patients with diabetes: antiresorptive versus anabolic?

PURPOSE OF REVIEW

The pathogenesis of bone fragility in diabetes has not been fully characterized. The antifracture efficacy of available therapies remains unproven in patients with diabetes. We aim to collate current evidence of the treatment of diabetic bone fragility, and to provide a rationale for considering optimal therapeutic option in patients with diabetes.

RECENT FINDINGS

The antifracture efficacy of antiresorptive and anabolic therapies is well established in patients without diabetes. Studies in patients with osteoporosis have shown that anabolic therapies lead to faster and larger benefits to bone mineral density and offer greater protection against fracture than antiresorptive therapies. Available data suggest that antiresorptive and anabolic therapies have similar effect on bone density and fracture risk reduction in patients with and without diabetes. However, the evidence in diabetes is limited to observational studies and post hoc analyses of osteoporosis studies.

SUMMARY

There are no specific guidelines for the treatment of bone fragility in patients with diabetes. We offer a rationale for use of anabolic therapies in diabetes which is a low bone formation state, in contrast to postmenopausal osteoporosis that is characterized by increased bone turnover. Prospective studies evaluating the effect of available therapies on bone quality and fracture outcomes in patients with diabetes are needed.

Management of bone fragility in type 2 diabetes: Perspective from an interdisciplinary expert panel

AIM

Bone fragility is increasingly recognized as a relevant complication of type 2 diabetes (T2D) and diabetic patients with fragility fractures have higher mortality rates than non diabetic individuals or diabetic patients without fractures. However, current diagnostic approaches for fracture risk stratification, such as bone mineral density measurement or the use of risk assessment algorithms, largely underestimate fracture risk in T2D patients. A multidisciplinary expert panel was established in order to in order to formulate clinical consensus recommendations on bone health assessment and management of fracture risk in patients with T2D.

DATA SYNTHESIS

The following key questions were addressed: a) which are the risk factors for bone fragility in T2D?, b) which diagnostic procedures can be currently used to stratify fracture risk in T2D patients?, c) which are the effects of antidiabetic treatments on bone?, and d) how to prevent and treat bone fragility in T2D patients? Based on the available data members of this panel suggest that the stratification of fracture risk in patients with diabetes should firstly rely on the presence of a previous fragility fracture and on the individual risk profile, with the inclusion of T2D-specific risk factors (namely T2D duration above 10 yrs, presence of chronic T2D complications, use of insulin or thiazolidinediones and persistent HbA1c levels above 8% for at least 1 year). Two independent diagnostic approaches were then suggested in the presence or the absence of a prevalent fragility fracture, respectively.

CONCLUSIONS

Clinical trials in T2D patients at risk for fragility fractures are needed to determine the efficacy and safety of available antiresorptive and anabolic agents in this specific setting.

Risk Factors for Incident Fracture in Older Adults With Type 2 Diabetes: The Framingham Heart Study

OBJECTIVE

To identify risk factors for fracture in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This prospective study included members of the Framingham Original and Offspring Cohorts. Type 2 diabetes was defined as fasting plasma glucose >125 mg/dL or use of type 2 diabetes therapy. We used repeated-measures Cox proportional hazards regression to calculate hazard ratios (HRs) and 95% CIs for associations between potential predictors and incidence of fragility fracture.

RESULTS

Participants included 793 individuals with type 2 diabetes. Mean ± SD age was 70 ± 10 years; 45% were women. A total of 106 incident fractures occurred over 1,437 observation follow-up intervals. Fracture incidence increased with age (adjusted HRs 1.00, 1.44 [95% CI 0.65, 3.16], and 2.40 [1.14, 5.04] for <60, 60-70, and >70 years, respectively; P _trend = 0.02), female sex (2.23 [1.26, 3.95]), HbA_1c (1.00, 2.10 [1.17, 3.75], and 1.29 [0.69, 2.41] for 4.45-6.46% [25-47 mmol/mol], 6.50-7.49% [48-58 mmol/mol], and 7.50-13.86% [58-128 mmol/mol]; P _trend =0.03), falls in past year (1.00, 1.87 [0.82, 4.28], and 3.29 [1.34, 8.09] for no falls, one fall, and two or more falls; P _trend =0.03), fracture history (2.05 [1.34, 3.12]), and lower grip strength (0.82 [0.69, 0.99] per 5-kg increase). Femoral neck bone mineral density, BMI, smoking, physical function, chronic diseases, medications, and physical function were not associated with fracture incidence.

CONCLUSIONS

Prior falls, fractures, low grip strength, and elevated HbA_1c are risk factors for fractures in older adults with type 2 diabetes. Evaluation of these factors may improve opportunities for early intervention and reduce fractures in this high-risk group.

Application of Propolis in Protecting Skeletal and Periodontal Health-A Systematic Review

Chronic inflammation and oxidative stress are two major mechanisms leading to the imbalance between bone resorption and bone formation rate, and subsequently, bone loss. Thus, functional foods and dietary compounds with antioxidant and anti-inflammatory could protect skeletal health. This review aims to examine the current evidence on the skeletal protective effects of propolis, a resin produced by bees, known to possess antioxidant and anti-inflammatory activities. A literature search was performed using Pubmed, Scopus, and Web of Science to identify studies on the effects of propolis on bone health. The search string used was (i) propolis AND (ii) (bone OR osteoporosis OR osteoblasts OR osteoclasts OR osteocytes). Eighteen studies were included in the current review. The available experimental studies demonstrated that propolis could prevent bone loss due to periodontitis, dental implantitis, and diabetes in animals. Combined with synthetic and natural grafts, it could also promote fracture healing. Propolis protects bone health by inhibiting osteoclastogenesis and promoting osteoblastogenesis, partly through its antioxidant and anti-inflammatory actions. Despite the promising preclinical results, the skeletal protective effects of propolis are yet to be proven in human studies. This research gap should be bridged before nutraceuticals based on propolis with specific health claims can be developed.

Positive effects of low LDL-C and statins on bone mineral density: an integrated epidemiological observation analysis and Mendelian randomization study

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) is suggested to play a role in osteoporosis but its association with bone metabolism remains unclear. Effects of LDL-C-lowering drugs on bone are also controversial. We aim to determine whether LDL-C is linked causally to bone mineral density (BMD) and assess the effects of LDL-C-lowering drugs on BMD.

METHODS

Association between blood lipid levels and BMD was examined by epidemiological observation analyses in a US representative cohort NHANES III (n = 3638) and the Hong Kong Osteoporosis Study (HKOS; n = 1128). Two-sample Mendelian randomization (MR), employing genetic data from a large-scale genome-wide association study (GWAS) of blood lipids (n = 188 577), total body BMD (TB-BMD) (n = 66 628) and estimated BMD (eBMD) (n= 142 487), was performed to infer causality between LDL-C and BMD. Genetic proxies for LDL-C-lowering drugs were used to examine the drugs' effects on BMD.

RESULTS

In the NHANES III cohort, each standard deviation (SD) decrease in LDL-C was associated with a 0.045 SD increase in femoral neck BMD (95% CI: 0.009 - 0.081; P = 0.015). A similar increase in BMD was observed in the HKOS at femoral neck and lumbar spine. In MR analysis, a decrease in genetically predicted LDL-C was associated with an increase in TB-BMD {estimate per SD decrease, 0.038 [95% confidence interval (CI): 0.002 - 0.074]; P = 0.038} and eBMD [0.076 (0.042 - 0.111); P = 1.20x10-5]. Reduction in TB-BMD was causally associated with increased LDL-C [0.035 (0.033 - 0.066); P = 0.034]. Statins' LDL-C-lowering proxies were associated with increased TB-BMD [0.18 (0.044 - 0.316); P = 9.600x10-3] and eBMD [0.143 (0.062 - 0.223); P = 5.165x10-4].

CONCLUSIONS

Negative causal association exists between LDL-C level and BMD. Statins' LDL-C-lowering effect increases BMD, suggesting their protective effect on bone.

Association Between Parental Type 1 and Type 2 Diabetes Diagnosis and Major Osteoporotic Fracture Risk in Adult Offspring: A Population-Based Cohort Study

OBJECTIVES

Previous research suggests an intergenerational influence of diabetes on bone health. We examined the association between parental diabetes and major osteoporotic fracture (MOF) risk in offspring.

METHODS

This population-based cohort study used de-identified administrative health data from Manitoba, Canada, which capture population-level records of hospitalizations, physician visits and drug dispensations. The cohort included individuals 40⁺ years with at least 1 parent identified in the data between 1997 and 2015. The exposure was parental diagnosis of diabetes since 1970; the outcome was offspring incident MOF diagnosis of the hip, forearm, spine or humerus. Both measures were identified from hospital and physician visit records using validated case definitions. Multivariable Cox proportional hazards regression models tested the association of parental diabetes and offspring MOF risk.

RESULTS

The cohort included 279,085 offspring; 48.5% were females and 86.8% were ≤44 years of age. Both parents were identified for 89.4% of the cohort; 36.7% had a parental diabetes diagnosis. During a median follow up of 12.0 (interquartile range, 6.0 to 18.0) years, 8,762 offspring had a MOF diagnosis. After adjusting for fracture risk factors, parental diabetes diagnosis was not associated with MOF risk, whether diagnosed in fathers (adjusted hazard ratio [aHR], 1.02; 95% confidence interval [CI], 0.97 to 1.08), mothers (aHR, 1.02; 95% CI, 0.97 to 1.07) or both parents (aHR, 1.01; 95% CI, 0.93 to 1.11). The results remained consistent in a stratified analysis by offspring sex, secondary analysis based on MOF site and sensitivity analyses.

CONCLUSIONS

The results indicate parental diabetes is not associated with offspring MOF risk.

Femur absorptiometry changes determined by X-ray image segmentation in mice under experimental diabetes and ovariectomy

AIM

The aim of the present work was to determine if both ovariectomy (OVX) and type 2 diabetes mellitus (T2DM) can change X-ray absorptiometry until reach the osteoporosis condition.

RESULTS

The segmentation allowed us to quantitatively determine the X-ray absorption in the femurs of mice subjected to OVX, T2DM and both pathologies together.

CONCLUSIONS

The test subjects suffering from the mentioned pathologies separately or together, did not reach the osteoporosis condition when they were 30 weeks old.

Genistein prevents bone loss in type 2 diabetic rats induced by streptozotocin

Background

Diabetic osteoporosis has become a severe public health problem in the aging societies. Genistein has been reported to play an important role in preventing and treating metabolic diseases via its anti-inflammatory, antioxidant, anti-estrogenic, and estrogen-like functions.

Objective

We aimed to investigate whether genistein exerts bone-protective effect on diabetic rats induced by 35 mg/kg streptozotocin (STZ) plus a 4-week high-fat diet.

Design

Sprague–Dawley rats were randomly divided into four groups: (1) control group, (2) type 2 diabetes mellitus (T2DM) model group, (3) T2DM with 10 mg/kg genistein, and (4) T2DM with 30 mg/kg genistein. After an 8-week treatment with genistein, the femurs, tibias, and blood were collected from all rats for further analysis.

Results

Genistein at 10 mg/kg showed little effect on diabetic osteoporosis, whereas genistein at 30 mg/kg significantly improved glucose and bone metabolisms compared with diabetic rats. Our results showed that 30 mg/kg genistein significantly increased bone mineral density, serum osteocalcin, and bone alkaline phosphatase. Genistein also effectively lowered fasting blood glucose, tartrate-resistant acid phosphatase 5b, tumor necrosis factor-α, interleukin-6, and numbers of adipocytes and osteoclasts. Compared with the T2DM group, protein levels of receptor activator of nuclear factor κB ligand (RANKL) and peroxisome proliferator-activated receptor-γ (PPAR-γ) were decreased, while protein levels of osteoprotegerin (OPG), β-catenin, and runt-related transcription factor 2 (Runx-2) were increased after genistein intervention.

Conclusion

Genistein could effectively improve abnormal bone metabolism in STZ-induced diabetic rats; the underlying molecular mechanisms might be related to OPG/RANKL, PPAR-γ, and β-catenin/Runx-2 pathways.

Regulation of Osteoclast Differentiation and Activity by Lipid Metabolism

Bone is a dynamic tissue and is constantly being remodeled by bone cells. Metabolic reprogramming plays a critical role in the activation of these bone cells and skeletal metabolism, which fulfills the energy demand for bone remodeling. Among various metabolic pathways, the importance of lipid metabolism in bone cells has long been appreciated. More recent studies also establish the link between bone loss and lipid-altering conditions—such as atherosclerotic vascular disease, hyperlipidemia, and obesity—and uncover the detrimental effect of fat accumulation on skeletal homeostasis and increased risk of fracture. Targeting lipid metabolism with statin, a lipid-lowering drug, has been shown to improve bone density and quality in metabolic bone diseases. However, the molecular mechanisms of lipid-mediated regulation in osteoclasts are not completely understood. Thus, a better understanding of lipid metabolism in osteoclasts can be used to harness bone cell activity to treat pathological bone disorders. This review summarizes the recent developments of the contribution of lipid metabolism to the function and phenotype of osteoclasts.

The risk of hip fractures in individuals over 50 years old with prediabetes and type 2 diabetes - A longitudinal nationwide population-based study

BACKGROUND

The present study aimed to investigate the association between type 2 diabetes mellitus (T2DM) and hip fractures using a large-scale nationwide population-based cohort that is representative of the Republic of Korea. We determined the risks of hip fractures in individuals with prediabetes and T2DM with different diabetes durations, and compared them with the risks of hip fractures in individuals without T2DM.

METHODS

A total of 5,761,785 subjects over 50 years old who underwent the National Health Insurance Service medical checkup in 2009-2010 were included. Subjects were classified into 5 groups based on the diabetes status; Normal, Prediabetes, Newly-diagnosed T2DM, T2DM less than 5 years, and T2DM more than 5 years. They were followed from the date of the medical checkup to the end of 2016. The endpoint was a new development of hip fracture during follow-up. The hazard ratios (HRs) and 95% confidence intervals (CIs) of hip fractures for each group were analyzed using Cox proportional hazard regression models after adjusting for age, sex, smoking, alcohol drinking, regular exercise, body mass index, hypertension, dyslipidemia, and chronic kidney disease.

RESULTS

The HRs of hip fractures were 1 in the Normal group, 1.032 (95% CI: 1.009, 1.056) in the Prediabetes group, 1.168 (95% CI: 1.113, 1.225) in the Newly-diagnosed T2DM2, 1.543 (95% CI: 1.495, 1.592) in the T2DM less than 5 years and 2.105 (95% CI: 2.054, 2.157) in the T2DM more than 5 years. The secular trend of the HRs of hip fractures according to the duration of T2DM was statistically significant (P < .001). Subgroup analyses also showed the same increasing pattern of the HRs of hip fractures according to the duration of T2DM in both sexes and all age groups (50-64 years, 65-74 years, over 75 years).

CONCLUSIONS

In summary, this large-scale, retrospective, longitudinal, nationwide population-based cohort study of 5,761,785 subjects demonstrated that the risks of hip fractures started to increase in prediabetes and was associated linearly with the duration of T2DM. The secular trend of risks of hip fractures according to the duration of T2DM was consistent in both sexes and all age groups.

Thyroid Hormones, Glucocorticoids, Insulin, and Bone

Several endocrine systems have important effects on bone tissue. Thyroid hormones are essential for normal growth and development. Excess of these hormones will result in clinically significant changes that may require intervention. Glucocorticoids also have a marked effect on bone metabolism by several pathways. Their endogenous or exogenous excess will induce pathological processes that might elevate the risk of fractures. Insulin and the carbohydrate metabolism elicit a physiological effect on bone; however, the lack of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) have deleterious influence on bone tissue.

Diabetes mellitus and risk of low-energy fracture: a meta-analysis

BACKGROUND

Low-energy fracture risk is significantly increased in diabetes mellitus, the purpose of this article is to systematically evaluate the association between diabetes mellitus and risk for low-energy fracture.

METHODS

We conducted a systematic literature search of Medline, Embase, Science Citation Index, Wiley Online Library database through January 2019. Pooled relative risks (RR) with corresponding 95% confidence intervals (95% CI) were calculated with random-effects model to assess the strength of association.

RESULTS

Thirty-seven studies met the inclusion criteria, which included 3,123,382 participants. The pooled RR of any fracture in people with diabetes mellitus was 1.5 (95% CI 1.3-1.8; P < 0.05). The significant association not found in subgroup analysis of prospective design, follow-up period ≥ 10 year (all P > 0.05). The pooled RR of hip fracture in people with diabetes mellitus was 2.0 (95% CI 1.8-2.3; P < 0.05). In addition, subgroup analysis shown higher risk of hip fracture in type 1 diabetes (RR: 5.3). The pooled RR of vertebral fracture with diabetes mellitus was 1.4 (95% CI 0.9-2.2; P = 0.196). Subgroup analysis by type of diabetes showed that the RR of vertebral fracture for patients with unknown-type diabetes was 2.4 (95% CI 1.4-4.0; P < 0.05). Diabetes mellitus was associated with fractures at other sites, and effect estimates was statically significant.

CONCLUSIONS

Diabetes mellitus is an independent risk factor for low-energy fracture, and this relationship is more pronounced in hip fracture.

Probiotics ameliorate pioglitazone-associated bone loss in diabetic rats

Background

Pioglitazone, as a PPAR gamma agonist, is used for the management of type 2 diabetes mellitus. Nevertheless, evidence showed that the therapeutic modulation of PPAR gamma activity using pioglitazone might be linked with bone mass reduction and fracture risk in type 2 diabetes mellitus patients. The objective of the current research was to inspect the preventive role of some types of probiotic strains, including (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, Bifidobacterium longum, and Bacillus coagulans) against pioglitazone-induced bone loss.

Methods

Streptozotocin (60 mg/kg) was administered for diabetes induction. Diabetic rats were fed orally with pioglitazone (300 mg/kg) and probiotics (1 × 109 CFU/ml/day) alone and in combination for four weeks. Dual-energy X-ray absorptiometry (DXA) was used to assess BMD, BMC, and area of the femur, spine, and tibia at the end of the experiment. Serum glucose, serum calcium (Ca), alkaline phosphatase (ALP), phosphorus (P), Blood urea nitrogen (BUN), creatinine, and urine calcium were also analyzed.

Results

Administration of pioglitazone and probiotics alone and, in combination, significantly reduced elevated blood glucose. Pioglitazone treatment significantly increased urinary calcium and BUN and decreased ALP and creatinine. Co-treatment of probiotics with pioglitazone significantly decreased urinary calcium, creatinine, and ALP. Pioglitazone showed detrimental effects on femur-BMD, whereas treatment with probiotics remarkably ameliorated these effects. Among the tested probiotics, Bifidobacterium longum displayed the best protective effects on pioglitazone-induced bone loss in diabetic rats.

Conclusion

This study suggests probiotic supplementation in diabetic patients on pioglitazone regime could be considering as an excellent strategy to ameliorate bone loss induced by pioglitazone.

Energy metabolism: A newly emerging target of BMP signaling in bone homeostasis

Energy metabolism is the process of generating energy (i.e. ATP) from nutrients. This process is indispensable for cell homeostasis maintenance and responses to varying conditions. Cells require energy for growth and maintenance and have evolved to have multiple pathways to produce energy. Both genetic and functional studies have demonstrated that energy metabolism, such as glucose, fatty acid, and amino acid metabolism, plays important roles in the formation and function of bone cells including osteoblasts, osteocytes, and osteoclasts. Dysregulation of energy metabolism in bone cells consequently disturbs the balance between bone formation and bone resorption. Metabolic diseases have also been reported to affect bone homeostasis. Bone morphogenic protein (BMP) signaling plays critical roles in regulating the formation and function of bone cells, thus affecting bone development and homeostasis. Mutations of BMP signaling-related genes in mice have been reported to show abnormalities in energy metabolism in many tissues, including bone. In addition, BMP signaling correlates with critical signaling pathways such as mTOR, HIF, Wnt, and self-degradative process autophagy to coordinate energy metabolism and bone homeostasis. These findings will provide a newly emerging target of BMP signaling and potential therapeutic strategies and the improved management of bone diseases. This review summarizes the recent advances in our understanding of (1) energy metabolism in regulating the formation and function of bone cells, (2) function of BMP signaling in whole body energy metabolism, and (3) mechanistic interaction of BMP signaling with other signaling pathways and biological processes critical for energy metabolism and bone homeostasis.

Influence of melatonin on the kidneys of rats with experimental diabetes mellitus type 2

Diabetes mellitus is characterized by numerous pathological changes in the body. Under conditions of diabetes, hyperglycemic intoxication of the organism rapidly develops, which in turn leads to an increase of oxidative stress with subsequent disturbance of the anatomical and functional integrity of the components of organisms. Today, the search for the substances that would contribute to the multi-vectoral effect on the negative consequences of diabetes is actively being pursued. Melatonin is one of such substances. In this work, we studied the effect of melatonin on oxidative stress markers (oxidized products content, activities of superoxide dismutase and catalase), the concentration of metabolism end products (creatinine and urea), main ions concentration (potassium and chlorine), and protein content (total protein and electropherogram in polyacrylamide gel), enzymatic activity of gamma-glutamyltrasferase in the cytosolic fraction of rat kidneys under condition of type 2 diabetes mellitus (EDM2). Experimental studies were performed on 18 white adult Wistar rats divided into three groups (control, group with EDM2 and group with EDM2, which were treated with melatonin). The increase of concentration of oxidized products, the activity of catalase and gamma-glutamyltrasferase, creatinine, urea, K+ and Cl– and the decrease of concentration of superoxide dismutase in the rats’ kidneys was noted after development of EDM2. The electrophoretic proteinogram of the cytosolic proteins obtained from the rats’ kidneys showed an increase of content of high-molecular-weight and a decrease of low-molecular-weight proteins. Administration of melatonin in a dose of 10 mg/kg of body weight for 7 days after development of EDM2 restored the studied parameters almost to the control group values. Therefore, the influence of melatonin can prevent chronic development of oxidative stress in kidneys under hyperglycemic intoxication, and lead to normalization of kidney function and the restoration of homeostasis.