Osteoporosis among patients with type 1 and type 2 diabetes

MiR-322-5p is involved in regulating chondrocyte proliferation and differentiation in offspring's growth plate of maternal gestational diabetes

Pregestational diabetes mellitus (PGDM) has an impact on fetal bone formation, but the underlying mechanism is still obscure. Although miRNAs have been extensively investigated throughout bone formation, their effects on fetal bone development caused by PGDM still need clarification. This study intends to examine the mechanism by which hyperglycemia impairs the bone formation of offspring via miR-322-5p (miR-322). In this study, miR-322 was selected by systemically screening utilizing bioinformatics and subsequent validation experiments. Using streptozotocin (STZ)-induced diabetic mice and ATDC5 cell lines, we found that miR-322 was abundantly expressed in the proliferative and hypertrophic zones of the growth plate, and its expression pattern was disturbed in the presence of hyperglycemia, suggesting that miR-322 is involved in the chondrocyte proliferation and differentiation in absence/presence of hyperglycemia. This observation was proved by manipulating miR-322 expression in ATDC5 cells by transfecting mimic and inhibitor of miR-322. Furthermore, Adamts5, Col12a1, and Cbx6 were identified as the potential target genes of miR-322, verified by the co-transfection of miR-322 inhibitor and the siRNAs, respectively. The evaluation criteria are the chondrocyte proliferation and differentiation and their relevant key gene expressions (proliferation: Sox9 and PthIh; differentiation: Runx2 and Col10a1) after manipulating the gene expressions in ATDC5 cells. This study revealed the regulative role miR-322 on chondrocyte proliferation and differentiation of growth plate by targeting Adamts5, Col12a1, and Cbx6 in hyperglycemia during pregnancy. This translational potential represents a promising avenue for advancing our understanding of bone-related complications in diabetic pregnancy and mitigating bone deficiencies in diabetic pregnant individuals, improving maternal and fetal outcomes.

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.

Diabetic microvascular disease in non-classical beds: the hidden impact beyond the retina, the kidney, and the peripheral nerves

Diabetes microangiopathy, a hallmark complication of diabetes, is characterised by structural and functional abnormalities within the intricate network of microvessels beyond well-known and documented target organs, i.e., the retina, kidney, and peripheral nerves. Indeed, an intact microvascular bed is crucial for preserving each organ's specific functions and achieving physiological balance to meet their respective metabolic demands. Therefore, diabetes-related microvascular dysfunction leads to widespread multiorgan consequences in still-overlooked non-traditional target organs such as the brain, the lung, the bone tissue, the skin, the arterial wall, the heart, or the musculoskeletal system. All these organs are vulnerable to the physiopathological mechanisms that cause microvascular damage in diabetes (i.e., hyperglycaemia-induced oxidative stress, inflammation, and endothelial dysfunction) and collectively contribute to abnormalities in the microvessels' structure and function, compromising blood flow and tissue perfusion. However, the microcirculatory networks differ between organs due to variations in haemodynamic, vascular architecture, and affected cells, resulting in a spectrum of clinical presentations. The aim of this review is to focus on the multifaceted nature of microvascular impairment in diabetes through available evidence of specific consequences in often overlooked organs. A better understanding of diabetes microangiopathy in non-target organs provides a broader perspective on the systemic nature of the disease, underscoring the importance of recognising the comprehensive range of complications beyond the classic target sites.

Association between renal function and bone mineral density in patients with type 2 diabetes mellitus

Background

This study evaluated the association between renal function, assessed by serum creatinine and estimated glomerular filtration rate (eGFR) according to the Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) equations, and bone mineral density (BMD) in Chinese patients with type 2 diabetes mellitus (T2DM).

Methods

1322 patients with T2DM were included, and their basic clinical information, serum biochemical tests, and BMD at the total hip and femur neck were collected. Multivariate adjusted linear regression, smooth curve fitting and a piecewise linear regression model were used to analyze linear and nonlinear associations. Age, BMI, drinking, smoking, systolic blood pressure and diastolic blood pressure, FBG, HbA1C, course of diabetes, hsCRP, TC, TG, HDL-C, LDL-C, Ca, P, PTH, ALP, OC, P1NP, β-CTX and 25(OH)D were adjusted.

Results

After adjusting the variables, no correlation between eGFR CG and eGFR MDRD and femur neck BMD was observed in women, men, or the total population. The eGFR CG and eGFR MDRD had a significant positive association with total hip BMD in men and the total population with T2DM. With a 10-unit decrease in eGFR CG, total hip BMD reduced by 0.012 g/cm² in men and 0.010 g/cm² the total population. Total hip BMD reduced by 0.014 g/cm² in men and 0.022 g/cm² in the total population with a 10-unit decrease in eGFR MDRD. There was no correlation between eGFR CG or eGFR MDRD and total hip BMD in female participants.

Conclusion

Impaired renal function was associated with decreased total hip BMD in men and the total population with T2DM. No associated between renal function with femur neck BMD was observed.

High glucose impairs osteogenic differentiation of embryonic stem cells via early diversion of beta-catenin from Forkhead box O to T cell factor interaction

BACKGROUND

Diabetes, which is characterized by an increase in blood glucose concentration, is accompanied by low bone turnover, increased fracture risk, and the formation of embryonic skeletal malformations. Yet, there are few studies elucidating the underlying alterations in signaling pathways leading to these osteogenic defects. We hypothesized here that bone formation deficiencies in a high glucose environment result from altered activity of beta-catenin (CTNNB1), a key contributor to osteogenic differentiation, dysregulation of which has also been implicated in the development of diabetes.

METHODS

To test this hypothesis, we used a previously established embryonic stem cell (ESC) model of differentiation that mimics the diabetic environment of the developing embryo. We differentiated murine ESCs within osteogenic-inducing media containing either high (diabetic) or low (physiological) levels of D-glucose and performed time course analyses to study the influence of high glucose on early and late bone cell differentiation.

RESULTS

Endpoint measures for osteogenic differentiation were reduced in a glucose-dependent manner and expression of precursor-specific markers altered at multiple time points. Furthermore, transcriptional activity of the lymphoid enhancer factor (LEF)/T cell factor (TCF) transcription factors during precursor formation stages was significantly elevated while levels of CTNNB1 complexed with Forkhead box O 3a (FOXO3a) declined. Modulation of AKT, a known upstream regulator of both LEF/TCF and FOXO3a, as well as CTNNB1 rescued some of the reductions in osteogenic output seen in the high glucose condition.

CONCLUSIONS

Within our in vitro model, we found a clear involvement of LEF/TCF and FOXO3a signaling pathways in the regulation of osteogenic differentiation, which may account for the skeletal deficiencies found in newborns of diabetic mothers.

Experimental Study on the Inhibition of RANKL-Induced Osteoclast Differentiation In Vitro by Metformin Hydrochloride

OBJECTIVE

Establishment of an in vitro osteoclast induction model under nuclear factor-κB receptor activator ligand (RANKL) induction for investigating the effect of metformin hydrochloride (Met) on osteoclast differentiation.

METHODS

RANKL induced the differentiation of mouse bone marrow macrophages (BMMs) into osteoclasts in vitro, and Met was added at different concentrations for intervention during the induction process. After 5 d of culture and fixation, the number of osteoclasts was counted by tartrate-resistant acid phosphatase (TRAP) staining and F-actin staining, and the function of osteoclasts was examined with hydroxyapatite-coated plates. Real-time fluorescence quantitative PCR was performed to detect the expression of Cathepsin K, osteoclast associated receptor (OSCAR), and TRAP, and the effect of Met on Mitogen-activated protein kinases (MAPK) signaling pathway was detected by Western blot.

RESULTS

Met significantly reduced osteoclast formation, F-actin ring formation, bone resorption, and the expression of relevant genes Cathepsin K, OSCAR, and TRAP. The Western blotting study demonstrated that Met inhibited the MAPK signaling pathway by decreasing the phosphorylation of extracellular regulated protein kinase (ERK), which plays important roles in osteoclast formation.

CONCLUSION

Metformin hydrochloride inhibited the differentiation of osteoclasts, decreased the bone resorption area, and suppressed phosphorylation of ERK in vitro.

AMD3465 (hexahydrobromide) rescues the MG63 osteoblasts against the apoptosis induced by high glucose

Diabetic osteoporosis (DOP) is a serious complication of diabetes, which brings a heavy burden to patients' families and society. The SDF-1/CXCR4 signal pathway may be a target to prevent articular cartilage degeneration. In this study, we studied the effects of high glucose (20 mmol/L) and CXCR4 antagonist AMD3465 (10 μmol/L) on the apoptosis and gene expression of osteoblast-like cells MG63 to determine a new treatment for DOP. CCK8 and clone formation assays confirmed that AMD3465 resisted the decrease of proliferation caused by high glucose. According to the results of scratch and transwell analysis, AMD3465 could remedy the decrease of cell migration and invasion induced by high glucose. The results of flow cytometry analysis and double staining with Hoechst and PI showed AMD3465 corrected the apoptosis induced by high glucose. In addition, high glucose regulated the expression of cell cycle- and apoptosis-related proteins, while AMD3465 blocked the regulation of high glucose. Furthermore, high glucose enhanced the expression levels of SDF-1 and CXCR4 in MG63 cells, as well as the release of MMP1, 3, 9 and 13. AMD3465 inhibited the release of MMPs. The results showed that AMD3465 resisted the apoptosis of MG63 cells induced by high glucose, provided a new strategy for the therapy of DOP.

Diabetes and Bone Fragility

Diabetes is a highly prevalent disease with complications that impact most bodily systems. However, the impact of diabetes on bone health is frequently ignored or underestimated. Both type 1 (T1D) and type 2 diabetes (T2D) are associated with a higher risk of fractures, albeit through different mechanisms. T1D is characterized by near total insulinopenia, which affects the anabolic tone of bone and results in reduced bone mineral density (BMD). Meanwhile, patients with T2D have normal or high BMD, but carry an increased risk of fractures due to alterations of bone microarchitecture and a local humoral environment that stimulates osteoclast activity. Chronic hyperglycemia induces non-enzymatic glycation of collagen in both types of diabetes. Epidemiological evidence confirms a largely increased fracture risk in T1D and T2D, but also that it can be substantially reduced by opportune monitoring of fracture risk and appropriate treatment of both diabetes itself and osteopenia or osteoporosis if they are present. In this review, we summarize the mechanistic, epidemiological, and clinical evidence that links diabetes and bone fragility, and describe the impact of available diabetes treatments on bone health.

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.

Osteogenesis of adipose-derived stem cells from patients with glucose metabolism disorders

Background

Adipose derived stem cells (ADSCs) are clinically widely used somatic stem cells obtained from white adipose tissue. They are characterized by ability to differentiate e.g. into osteoblasts and might successfully regenerate bone tissue in fracture repair. However, the main problem of somatic stem cells is a documented influence of various diseases, drugs or age which can inhibit cells activity. Therefore, in the present study, we investigated the influence of insulin resistance (IR) and type 2 diabetes (T2D) on the proliferation and differentiation potential of ADSCs.

Methods

The fat from subcutaneous abdominal adipose tissue was acquired by lipoaspiration from 23 voluntary participants, divided into three groups: with diabetes type 2, with insulin resistance and control healthy donors. The proliferative potential was analyzed by cell cytotoxicity assays and by mRNA expression of genes connected with proliferation. Flow cytometry was done for identifying proteins characteristic for mesenchymal stem cells and an analysis of osteogenic differentiation potential based on the assessment of osteogenic markers by real time RT-qPCR, and the evaluation of calcium deposition were also performed.

Results

The results showed that diabetes type 2 lowered the activity of ADSCs in proliferation assays and changed their phenotypical characteristics. Interestingly, we observed differences in the proliferation potential of ADSCs in patients with insulin resistance, which is often the first phase of diabetes, compared to the control. It might suggest that insulin resistance, early-stage T2D, alters the activity of cells. Moreover, expression of osteogenesis markers was higher in cells from T2D patients than in cells from patients with IR and control.

Conclusion

We conclude that type 2 diabetes changes the activity of stem cells, and insulin resistance influences on the proliferation of ADSCs.

Impact of Type 2 Diabetes Mellitus on Human Bone Marrow Stromal Cell Number and Phenotypic Characteristics

Human bone marrow-derived mesenchymal stromal cells (MSCs) have been investigated in numerous disease settings involving impaired regeneration because of the crucial role they play in tissue maintenance and repair. Considering the number of comorbidities associated with type 2 diabetes mellitus (T2DM), the hypothesis that MSCs mediate these comorbidities via a reduction in their native maintenance and repair activities is an intriguing line of inquiry. Here, it is demonstrated that the number of bone marrow-derived MSCs in people with T2DM was reduced compared to that of age-matched control (AMC) donors and that this was due to a specific decrease in the number of MSCs with osteogenic capacity. There were no differences in MSC cell surface phenotype or in MSC expansion, differentiation, or angiogenic or migratory capacity from donors living with T2DM as compared to AMCs. These findings elucidate the basic biology of MSCs and their potential as mediators of diabetic comorbidities, especially osteopathies, and provide insight into donor choice for MSC-based clinical trials. This study suggests that any role of bone marrow MSCs as a mediator of T2DM comorbidity is likely due to a reduction in the osteoprogenitor population size and not due to a permanent alteration to the MSCs' capacity to maintain tissue homeostasis through expansion and differentiation.

Blockade of the OGF-OGFr pathway in diabetic bone

Purpose: This research investigated the presence and integrity of the opioid growth factor (OGF)-opioid growth factor receptor (OGFr) regulatory pathway in type 1 diabetic (T1D) rats, and investigated whether modulation of this axis by naltrexone (NTX) altered the composition of normal bone or fractured femurs. Materials and Methods: Diabetes was induced by streptozotocin; controls rats received buffer. Hyperglycemic animals were subjected to femur osteotomy, with randomized cohorts receiving either topical NTX or sterile saline in calcium carbonate. In experiment 2, hyperglycemic rats were injected daily for 3 weeks with either 30 mg/kg NTX or sterile saline. Expression levels of OGF and OGFr were measured by immunohistochemistry, bone composition was assessed by histomorphometry, and bone integrity was evaluated by µCT and 3-point bending. Results: Relative to normoglycemic bones, OGF and OGFr expression levels were increased 95% and 84%, respectively, in T1D bone; serum levels of OGF in T1D rats were elevated 23%. Hyperglycemia decreased the strength (26%), osteocalcin expression (17%), and number of proliferative (Ki67+) cells (32%) in intact femur. Topical NTX treatment of fractured femurs reduced the percentage of granulation tissue and increased cartilage. Systemic NTX treatment of diabetic rats increased strength by 21% and energy absorbed by105% in bone relative to measurements in saline-treated diabetic rats. Conclusions: The OGF-OGFr pathway appears to be dysregulated in the bone of T1D rats. Topical NTX treatment of T1D fractured bone accelerated some aspects of delayed diabetic fracture repair, and systemic NTX protected against some elements of compromised bone composition.

Rehmannia glutinosa Libosch Extracts Prevent Bone Loss and Architectural Deterioration and Enhance Osteoblastic Bone Formation by Regulating the IGF-1/PI3K/mTOR Pathway in Streptozotocin-Induced Diabetic Rats

Rehmanniae Radix Praeparata (RR, named as Shudihuang in traditional Chinese medicine), the steamed roots of Rehmannia glutinosa Libosch (Scrophulariaceae), has been demonstrated to have anti-diabetic and anti-osteoporotic activities. This study aimed to explore the protective effect and underlying mechanism of RR on diabetes-induced bone loss. It was found that RR regulated the alkaline phosphatase activity and osteocalcin level, enhanced bone mineral density, and improved the bone microarchitecture in diabetic rats. The catalpol (CAT), acteoside (ACT), and echinacoside (ECH) from RR increased the proliferation and differentiation of osteoblastic MC3T3-E1 cells injured by high glucose and promoted the production of IGF-1 and expression of related proteins in BMP and IGF-1/PI3K/mammalian target of rapamycin complex 1 (mTOR) signaling pathways. The verifying tests of inhibitors of BMP pathway (noggin) and IGF-1/PI3K/mTOR pathway (picropodophyllin) and molecular docking of IGF-1R further indicated that CAT, ACT, and ECH extracted from RR enhanced bone formation by regulating IGF-1/PI3K/mTOR signaling pathways. These findings suggest that RR may prove to be a promising candidate drug for the prevention and treatment of diabetes-induced osteoporosis.

The prevalence of osteoporosis among Iranian postmenopausal women with type 2 diabetes: A systematic review and meta-analysis

Osteoporosis is the most common metabolic bone disorder that is common in postmenopausal women with type 2 diabetes. Different studies have reported different prevalence of osteoporosis. This systematic review and meta-analysis was conducted to estimate the pooled prevalence of osteoporosis in Iranian postmenopausal women with type 2 diabetes. Search for eligible articles was performed using the keywords of osteoporosis, osteopenia, bone mineral density, OP, bone loss, Post menopaus*, diabetes, hyperglycemia, and Iran, and their possible combinations in the following databases: Scientific Information Database (SID), MagIran, PubMed, Scopus, and Web of Science. Heterogeneity between studies was examined with I². The data were analyzed using the meta-analysis method and random effects model with Stata version 11.0. The analysis of 4 papers with a sample size of 562 showed that the prevalence of osteoporosis in the lumbar spine and femoral neck of the Iranian post-menopausal women with type II diabetes was 25.26% (95% CI: 7.22-30.30) and 17.45% (95% CI: 0.25-34.65), respectively. Also, the prevalence of osteopenia in the lumbar spine and femoral neck of these patients was 45.23% (95% CI: 40.66-49.79) and 44.53% (95% CI: 36.60-52.47), respectively. There was no relationship between the prevalence of osteoporosis and osteopenia with sample size, year of publication, age and body mass index. Osteoporosis and osteopenia are prevalent in women, so healthy lifestyle education for these postmenopausal women are necessary to reduce the prevalence of these problems.

Type 2 diabetes is associated with higher trabecular bone density but lower cortical bone density: the Vietnam Osteoporosis Study

It is not clear why type 2 diabetes (T2D) has an increased risk of fracture despite higher areal bone mineral density. This study showed that compared with controls, T2D patients had higher trabecular bone density but lower cortical bone density, resulting in a lower bone strength.

INTRODUCTION

To define the association between type 2 diabetes and bone architecture and measures of bone strength.

METHODS

The study was part of the Vietnam Osteoporosis Study, in which 1115 women and 614 men aged ≥ 30 were randomly recruited from Ho Chi Minh City. HbA_1c levels were measured with analyzers ADAMS™ A_1c HA-8160 (Arkray, Kyoto, Japan). The diagnosis of T2D was made if HbA1c was ≥ 6.5%. Trabecular and cortical volumetric bone density (vBMD) was measured in the forearm and leg by a pQCT XCT2000 (Stratec, Germany). Polar stress strain index (pSSI) was derived from the pQCT measurements. Difference in bone parameters between T2D and non-diabetic individuals was assessed by the number of standard deviations (effect size [ES]) by the propensity score analysis.

RESULTS

The prevalence of T2D was ~ 8%. The results of propensity score matching for age, sex, and body mass index in 137 pairs of diabetic and non-diabetic individuals showed that T2D patients had significantly higher distal radius trabecular vBMD (ES 0.26; 95% CI, 0.02 to 0.50), but lower cortical vBMD (ES - 0.22; - 0.46 to 0.00) and reduced pSSI (ES - 0.23; - 0.47 to - 0.02) compared with non-diabetic individuals. Multiple linear regression analysis based on the entire sample confirmed the results of the propensity score analysis.

CONCLUSION

Compared with non-diabetic individuals, patients with T2D have greater trabecular but lower cortical vBMD which leads to lower bone strength.

Association of stroke subtypes with risk of hip fracture: a population-based study in Taiwan

Stroke is a critical issue of physical disability. This study aimed to investigate the association of stroke subtypes and hip fracture by using the Taiwan National Health Insurance Research Database. Significantly higher risks of hip fracture were found for female gender and intracerebral hemorrhagic stroke patients.

INTRODUCTION

Previous studies reported the increased hip fracture (HF) after acute stroke. Increased falling tendency immobilization-related sarcopenia and underlying comorbidities are related to HF in stroke patients. In the present study, we explored the association of different stroke subtypes and several comorbidities with poststroke HF.

METHODS

A population-based study was conducted using National Health Insurance Research Database (NHIRD) of Taiwan. First, we identified 17,168 patients diagnosed as having a stroke between January 1, 2002, and December 31, 2010. Then, we randomly selected 51,504 controls that never had a stroke and matched these controls to stroke patients in a 1:3 ratio by age (± 1 year old) and gender. Cox proportional hazards model was used to estimate hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Stroke patients had a significantly higher risk of HF (HR = 1.69). Female and male stroke patients had incidence rate ratios (IRRs) of 2.05 and 1.82 for HF, respectively. Significantly increased IRRs of 1.82, 1.52, and 2.63 for HF were found for stroke patients with 0, 1, and ≥ 2 comorbidities, respectively. All stroke patients, ischemic stroke patients, and intracerebral hemorrhagic (ICH) patients had HF risks of 1.65, 1.60, and 2.34, respectively.

CONCLUSION

Overall, stroke significantly increases the incidence of HF, and the risk of HF is significantly higher in ICH patients and female gender. We should identify stroke patients at risk of HF and pay more attention to prevent them from fall in poststroke long-term care.

Effects of low-intensity pulsed electromagnetic fields on bone microarchitecture, mechanical strength and bone turnover in type 2 diabetic db/db mice

Type 2 diabetic patients have impaired bone quality, leading to increased fracture risk. Substantial evidence demonstrates that pulsed electromagnetic fields (PEMF) could resist osteopenia/osteoporosis induced by estrogen deficiency and disuse. However, the effects of PEMF on osteopenia/osteoporosis associated with diabetes, especially for more prevalent type 2 diabetes, remain poorly understood. We herein investigated the skeletal effects and mechanisms of PEMF (15 Hz, 20 Gs) on leptin receptor-deficient db/db mice with typical type 2 diabetic symptoms. Our µCT results showed that 12-week PEMF exposure significantly improved both cancellous and cortical bone microarchitecture in db/db mice. Three-point bending and biomechanical indentation testing demonstrated that PEMF improved whole-bone structural properties and tissue-level material properties in db/db mice. PEMF significantly promoted bone formation in db/db mice evidenced by increased serum osteocalcin and bone mineral apposition rate, whereas PEMF exerted no observable alteration in bone resorption. Real-time PCR showed that PEMF upregulated tibial gene expression of osteoblastogenesis-related of canonical Wnt/β-catenin signaling but not osteoclastogenesis-related RANKL-RANK signaling in db/db mice. Our findings demonstrate that PEMF improved bone quantity and quality with obvious anabolic activities in db/db mice, and imply that PEMF might become a clinically applicable treatment modality for improving bone quality in type 2 diabetic patients.

Osteoporosis in Otherwise Healthy Patients with Type 2 Diabetes: A Prospective Gender Based Comparative Study

BACKGROUND AND OBJECTIVE

Type 2 diabetes mellitus (T2DM) may affect bone loss differentially in adult males and postmenopausal females. We evaluated the prevalence of osteoporosis in otherwise healthy adults with T2DM.

MATERIALS AND METHODS

In a cross-sectional study, adults with T2DM, aged 50 years and above, were evaluated for bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA) scan at spine and hip. T-score of ≤-2.5 was defined as osteoporosis and score -2.49 to -1.0 as osteopenia at either site. Correlation of low BMD with demographic, clinical, and laboratory parameters including serum Vitamin D and serum testosterone (in males) was evaluated.

RESULTS

In 200 patients, mean age was 64.5 ± 7.0 years and age differed significantly in males and females (P < 0.0001). Osteoporosis was present in 35.5% adults with T2DM. Significantly greater proportion of females had osteoporosis (49.5% vs. 22.3%, P < 0.0001). Frequency of osteoporosis at spine (33.5%) was higher than the same at hip (13.5%). Compared to males, significantly greater proportion of females had osteoporosis and osteopenia at both spine (P < 0.0001) and hip (P < 0.0001). Among all parameters assessed, a significant positive correlation of T-score at spine and hip was seen with body mass index in both males (r = 0.287, P = 0.003 at spine and r = 0.421, P < 0.0001 at hip) and females (r = 0.291, P = 0.004 at spine and r = 0.280, P = 0.010 at hip). There was no association of Vitamin D deficiency (45.5% patients) with either T-score and presence of osteoporosis either at spine (P = 0.388 and P = 0.177) or hip (P = 0.431 and P = 0.593).

CONCLUSION

Prevalence of osteoporosis in otherwise healthy T2DM was 35.5% with greater prevalence in females than males. Body mass but not Vitamin D or testosterone has an important role in the determination of bone loss in T2DM.

Peroxisome Proliferator-Activated Receptor α Facilitates Osteogenic Differentiation in MC3T3-E1 Cells via the Sirtuin 1-Dependent Signaling Pathway

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by lack of insulin and high glucose levels. T2DM can cause bone loss and fracture, thus leading to diabetic osteoporosis. Promoting osteogenic differentiation of osteoblasts may effectively treat diabetic osteoporosis. We previously reported that Sirtuin 1 (Sirt1), a NAD+-dependent deacetylase, promotes osteogenic differentiation through downregulation of peroxisome proliferator-activated receptor (PPAR) γ. We also found that miR-132 regulates osteogenic differentiation by downregulating Sirt1 in a PPARβ/δ-dependent manner. The ligand-activated transcription factor, PPARα, is another isotype of the peroxisome proliferator-activated receptor family that helps maintain bone homeostasis and promot bone formation. Whether the regulatory role of PPARα in osteogenic differentiation is mediated via Sirt1 remains unclear. In the present study, we aimed to determine this role and the underlying mechanism by using high glucose (HG) and free fatty acids (FFA) to mimic T2DM in MC3T3-E1 cells. The results showed that HG-FFA significantly inhibited expression of PPARα, Sirt1 and osteogenic differentiation, but these effects were markedly reversed by PPARα overexpression. Moreover, siSirt1 attenuated the positive effects of PPARα on osteogenic differentiation, suggesting that PPARα promotes osteogenic differentiation in a Sirt1-dependent manner. Luciferase activity assay confirmed interactions between PPARα and Sirt1. These findings indicate that PPARα promotes osteogenic differentiation via the Sirt1-dependent signaling pathway.

Bone mass loss is associated with systolic blood pressure in postmenopausal women with type 2 diabetes in Tibet: a retrospective cross-sectional study

We conducted an observational cross-section study to investigate the status of bone mineral mass of Tibetan postmenopausal women with type 2 diabetes and the possible predictors for osteoporosis. We found that prevalence of osteoporosis was 27.0% and blood pressure was an independent risk factor for bone mass loss.

INTRODUCTION

The aims of this study is to investigate the prevalence of osteoporosis in postmenopausal women with type 2 diabetes dwelling in Tibet and the possible risk factors for bone mass loss.

METHODS

We recruited 99 Chinese Tibetan postmenopausal women with type 2 diabetes from the department of endocrinology of People's Hospital Tibet Autonomous Region. Multiple sites of bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry (DXA). The subjects were divided into three groups based on BMD T-score: osteoporosis, osteopenia, and normal. The clinical characteristics were compared between groups. The risk factors for bone mass loss were assessed by multiple linear regression analysis.

RESULTS

Among diabetic postmenopausal women dwelling in high altitude, mean age was 62 ± 8 years, the median postmenopausal period was 12 years (5, 20), the median duration of diabetes mellitus was 3 years (1, 8), and mean BMI was 27.6 ± 4.2 kg/m². Patients (52.5%) had hypertension. The percentages of patients with osteoporosis, osteopenia and normal BMD were 27.3, 42.4, and 30.3%, respectively. HbA1c and systolic blood pressure (SBP) were independently associated with T-scores of spine; ages and SBP were independently associated with T-scores of femoral neck or hip.

CONCLUSIONS

Among diabetic postmenopausal women dwelling in high altitude, 27.3% patients have osteoporosis, 42.4% patients have osteopenia, and 30.3% are normal. The BMD T-score of spine was inversely associated with SBP and positively associated with HbA1c, while the BMD T-score of femoral neck or hip was inversely associated with ages and SBP.

Increased levels of Dickkopf-1 are indicative of Wnt/β-catenin downregulation and lower osteoblast signaling in children and adolescents with type 1 diabetes mellitus, contributing to lower bone mineral density

Higher levels of Dickkopf-1, which is an inhibitor of Wnt/β-catenin bone metabolic pathway, could be indicative of downregulated Wnt system, with possible lower osteoblast activation and higher osteoclast signaling in type 1 diabetes mellitus children and adolescents. Dickkopf-1 could significantly contribute to diabetes osteopathy.

INTRODUCTION

Increased fracture risk and elevated Dickkopf-1 levels, which is an inhibitor of Wnt/β-catenin bone metabolic pathway, have been documented in adult patients with type 2 diabetes mellitus (T2D), while no relevant data exist on childhood type 1 diabetes (T1D). Our aim was to study plasma Dickkopf-1 distribution in children and adolescents with T1D and to correlate Dickkopf-1 with metabolic bone markers and bone mineral density (BMD).

METHODS

We evaluated 40 children and adolescents with T1D (mean ± SD age 13.04 ± 3.53 years, T1D duration 5.15 ± 3.33 years) and 40 healthy age-matched and gender-matched controls (age 12.99 ± 3.3 years). Dickkopf-1 and bone metabolic markers were measured, while total body and lumbar spine BMD were evaluated with dual-energy X-ray absorptiometry (DXA).

RESULTS

Dickkopf-1 demonstrated a Gaussian distribution, with higher levels in T1D patients (13.56 ± 5.34 vs 11.35 ± 3.76 pmol/L, p = 0.024). Higher values were found in boys and in prepubertal children. Dickkopf-1 correlated positively with osteoprotegerin and fasting glucose in patients, while positive correlation with sclerostin and total soluble receptor activator of nuclear factor-kappaB ligand (s-RANKL) was found in controls. Positive correlations with C-telopeptide cross-links (CTX), osteocalcin, alkaline phosphatase, phosphate, and insulin-like growth factor 1 (IGF1) were documented in both groups. Lumbar spine Z-score was positively associated with Dickkopf-1 in controls, while a negative trend was found in patients.

CONCLUSIONS

Higher levels of Dickkopf-1 could indicate a downregulated Wnt/β-catenin system with possible lower osteoblast activation and higher osteoclast signaling in T1D children and adolescents. Dickkopf-1 could possibly be a significant contributor of T1D osteopathy. Future therapies could focus on Wnt/β-catenin metabolic pathway.

The Effect of Parathyroid Hormone on Osseointegration in Insulin-Treated Diabetic Rats

OBJECTIVES

Uncontrolled diabetes mellitus is associated with impaired osseointegration. Diabetic individuals might benefit from bone anabolic therapies. Intermittent administration of 1-34 parathyroid hormone (PTH) stimulates bone formation in rodent models. However, this anabolic effect fails in diabetic rats. Whether the anabolic effect of PTH can be achieved in insulin-controlled diabetic rats has not been investigated yet.

MATERIALS AND METHODS

After diabetes induction with streptozotocin in 40 female Wistar rats, the animals were randomly divided into 4 groups: diabetes, diabetes plus PTH, insulin-treated diabetes, and insulin-treated diabetes plus PTH. After 1 week, miniscrews were inserted in the tibiae. Osmotic pumps with insulin or saline solution were implanted. Animals received 60 mg/kg PTH or saline solution. Histomorphometric analysis was performed.

RESULTS

In diabetic rats, no changes of medullary periimplant bone area or bone-to-implant contacts (BICs) were achieved with or without treatment with PTH. However, also animals treated with insulin failed to response significantly to PTH regarding bone area (7.4 ± 4.1% and 8.1 ± 4.1%) and BICs (33.7 ± 16.9% and 49.9 ± 11.9%).

CONCLUSION

These results demonstrate that the metabolic characteristics of the diabetic rats produced a condition unable to respond to PTH treatment, even when hyperglycemia was controlled with insulin.

Diabetes Stimulates Osteoclastogenesis by Acidosis-Induced Activation of Transient Receptor Potential Cation Channels

Patients with type 1 diabetes have lower bone mineral density and higher risk of fractures. The role of osteoblasts in diabetes-related osteoporosis is well acknowledged whereas the role of osteoclasts (OCLs) is still unclear. We hypothesize that OCLs participate in pathological bone remodeling. We conducted studies in animals (streptozotocin-induced type 1 diabetic mice) and cellular models to investigate canonical and non-canonical mechanisms underlying excessive OCL activation. Diabetic mice show an increased number of active OCLs. In vitro studies demonstrate the involvement of acidosis in OCL activation and the implication of transient receptor potential cation channel subfamily V member 1 (TRPV1). In vivo studies confirm the establishment of local acidosis in the diabetic bone marrow (BM) as well as the ineffectiveness of insulin in correcting the pH variation and osteoclast activation. Conversely, treatment with TRPV1 receptor antagonists re-establishes a physiological OCL availability. These data suggest that diabetes causes local acidosis in the BM that in turn increases osteoclast activation through the modulation of TRPV1. The use of clinically available TRPV1 antagonists may provide a new means to combat bone problems associated with diabetes.

Sclerostin distribution in children and adolescents with type 1 diabetes mellitus and correlation with bone metabolism and bone mineral density

BACKGROUND AND OBJECTIVE

Sclerostin is an inhibitor of the Wnt/beta-catenin bone metabolic pathway. Increased sclerostin levels and reduced bone mineral density (BMD) have been documented in adult patients with diabetes mellitus (DM), predominantly in those with type 2 diabetes mellitus (T2DM). No relative data exist on childhood type 1 diabetes mellitus (T1DM). Our objective was to study plasma sclerostin in T1DM children and adolescents and controls and its correlations with metabolic bone markers and BMD.

SUBJECTS AND METHODS

This was a cross-sectional study that was conducted at an outpatient clinical center. Forty T1DM children and adolescents were evaluated (mean ± SD age: 13.04 ± 3.53 yr, T1DM duration: 5.15 ± 3.33 yr), along with 40 healthy matched controls (age 12.99 ± 3.3 yr). Sclerostin, soluble receptor activator of nuclear factor-kappaB ligand (s-RANKL), osteoprotegerin, osteocalcin, C-telopeptide crosslinks, electrolytes, parathyroid hormone (PTH), and total 25(OH)D were measured. Lumbar and subcranial total body BMD were evaluated with dual energy X-ray absorptiometry (DXA).

RESULTS

Sclerostin levels demonstrated a Gaussian distribution, with no significant difference between patients and controls (51.56 ± 12.05 vs. 50.98 ± 13.55 pmol/L, p = 0.84). Significantly lower values were found in girls and prepubertal children. Sclerostin values were significantly and gradually increased in children through pubertal Tanner stages 1-3, were reduced at stage 4 and increased again at pubertal stage 5. Sclerostin levels were positively correlated with logCTX (logarithm of C-terminal telopeptide crosslinks of type I collagen), logOsteocalcin (logarithm of Osteocalcin), magnesium, total body, and L1-L4 BMD z-score.

CONCLUSIONS

T1DM patients had similar levels of sclerostin with controls. Sclerostin correlated with bone resorption and formation markers and also with bone mass indices, gender, and pubertal stage. The decrease in sclerostin values observed in pubertal stage 4 adolescents coincides with the concurrent growth spurt, and is consistent with sclerostin physiology as an inhibiting signal.

Combined high-fat-resveratrol diet and RIP140 knockout mice reveal a novel relationship between elevated bone mitochondrial content and compromised bone microarchitecture, bone mineral mass, and bone strength in the tibia

SCOPE

While resveratrol (RSV) is associated with the prevention of high-fat (HF) diet-induced insulin resistance, the effects on bone health combined with an HF-diet is unknown. Therefore, we determined the effect of RSV on bone microarchitecture in the presence of an HF-diet, while also elucidating molecular adaptations within bone that could contribute to bone health status.

METHODS AND RESULTS

Male C57BL6 mice were provided control (10% fat) or HF-diet (60% fat) in the presence or absence of RSV for 12 weeks. While RSV prevented HF diet-induced glucose intolerance, HF-RSV compromised tibial microarchitecture, mineral mass, and strength. The compromised outcomes following HF-RSV corresponded with higher markers of osteoclast-activation and bone-resorption (decreased OPG/RANKL ratio; increased cathepsin K), as well as higher markers of tibial mitochondrial content. A molecular model of elevated mitochondrial content (RIP140 knock out (KO) mice) was utilized to determine proof-of-principle that increasing mitochondrial content coincides with decrements in bone health. RIP140 KO mice displayed higher markers of mitochondrial content, and similar to HF-RSV, had compromised bone microarchitecture, lower BMD/strength, and higher markers of osteoclast-activation/bone-resorption.

CONCLUSION

These data show that in the presence of an HF-diet, RSV negatively alters bone health, a process associated with increased mitochondrial content and markers of bone resorption.

Higher levels of s-RANKL and osteoprotegerin in children and adolescents with type 1 diabetes mellitus may indicate increased osteoclast signaling and predisposition to lower bone mass: a multivariate cross-sectional analysis

Simultaneous lower bone mineral density, metabolic bone markers, parathyroid hormone (PTH), magnesium, insulin-like growth factor 1 (IGF1), and higher levels of total soluble receptor activator of nuclear factor-kappa B ligand (s-RANKL), osteoprotegerin (OPG), and alkaline phosphatase (ALP) are indicative of lower osteoblast and increased osteoclast signaling in children and adolescents with type 1 diabetes mellitus, predisposing to adult osteopenia and osteoporosis.

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is a risk factor for reduced bone mass, disrupting several bone metabolic pathways. We aimed at identifying association patterns between bone metabolic markers, particularly OPG, s-RANKL, and bone mineral density (BMD) in T1DM children and adolescents, in order to study possible underlying pathophysiologic mechanisms of bone loss.

METHODS

We evaluated 40 children and adolescents with T1DM (mean ± SD age 13.04 ± 3.53 years, T1DM duration 5.15 ± 3.33 years) and 40 healthy age- and gender-matched controls (aged12.99 ± 3.3 years). OPG, s-RANKL, osteocalcin, C-telopeptide cross-links (CTX), IGF1, electrolytes, PTH, and total 25(OH)D were measured, and total body along with lumbar spine BMD were evaluated with dual energy X-ray absorptiometry (DXA). Multivariate regression and factor analysis were performed after classic inference.

RESULTS

Patients had significantly lower BMD, with lower bone turnover markers, PTH, magnesium, and IGF1 than controls, indicating lower osteoblast signaling. Higher levels of total s-RANKL, OPG, and total ALP were observed in patients, with log(s-RANKL) and OPG correlation found only in controls, possibly indicating increased osteoclast signaling in patients. Coupling of bone resorption and formation was observed in both groups. Multivariate regression confirmed simultaneous lower bone turnover, IGF1, magnesium, and higher total s-RANKL, OPG, and ALP in patients, while factor analysis indicated possible activation of RANK/RANKL/OPG system in patients and its association with magnesium and IGF1. Patients with longer disease duration or worse metabolic control had lower BMD.

CONCLUSIONS

T1DM children and adolescents have impaired bone metabolism which seems to be multifactorial. Reduced osteoblast and increased osteoclast signaling, resulting from multiple simultaneous disturbances, could lead to reduced peak bone accrual in early adulthood, predisposing to adult osteopenia and osteoporosis.

The Association between Urine Albumin to Creatinine Ratio and Osteoporosis in Postmenopausal Women with Type 2 Diabetes

Background

Osteoporosis is a progressive bone disease that is characterized by a decrease in bone mass density and destruction of microstructure, which can lead to an increased risk of fracture. Although many studies have been published about the relationship between end-stage renal disease and osteoporosis, research on the relationship between proteinuria and the prevalence of osteoporosis is still lacking.

Methods

We assessed 91 postmenopausal women with type 2 diabetes who visited our hospital from January 2009 to January 2012.

Results

Among 91 patients, the prevalence of osteoporosis and osteopenia was 35.2% (32 cases) and 32.9% (30 cases) according to bone mineral density. The patients with microalbuminuria and macroalbuminuria (urine albumin-to-creatinine ratio [UACR] ≥ 30) had a significantly higher incidence of osteoporosis compared to subjects with normoalbuminuria (P<0.05).

Conclusions

This study indicates that UACR may be a useful biomarker for increased risk of osteoporosis in postmenopausal women with type 2 diabetes who have been linked to higher UACR levels.

Fractal Behavior of the Pancreatic β-Cell Near the Percolation Threshold: Effect of the KATP Channel On the Electrical Response

The molecular system built with true chemical bonds or strong molecular interaction can be described using conceptual mathematical tools. Modeling of the natural generated ionic currents on the human pancreatic β-cell activity had been already studied using complicated analytical models. In our present contribution, we prove the same using our simple electrical model. The ionic currents are associated with different proteins membrane channels (K-Ca, K(v), K(ATP), Ca(v)-L) and Na/Ca Exchanger (NCX). The proteins are Ohmic conductors and are modeled by conductance randomly distributed. Switches are placed in series with conductances in order to highlight the channel activity. However, the KATP channel activity is stimulated by glucose, and the NCX's conductance change according to the intracellular calcium concentration. The percolation threshold of the system is calculated by the fractal nature of the infinite cluster using the Tarjan's depth-first-search algorithm. It is shown that the behavior of the internal concentration of Ca(2+) and the membrane potential are modulated by glucose. The results confirm that the inhibition of KATP channels depolarizes the membrane and increases the influx of [Ca(2+)]i through NCX and Ca(v)-L channel for high glucose concentrations.

Diabetes and Its Effect on Bone and Fracture Healing

Diabetes mellitus is a metabolic disorder that increases fracture risk, interferes with bone formation, and impairs fracture healing. Type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) both increase fracture risk and have several common features that affect the bone including hyperglycemia and increased advanced glycation end product (AGE) formation, reactive oxygen species (ROS) generation, and inflammation. These factors affect both osteoblasts and osteoclasts leading to increased osteoclasts and reduced numbers of osteoblasts and bone formation. In addition to fracture healing, T1DM and T2DM impair bone formation under conditions of perturbation such as bacteria-induced periodontal bone loss by increasing osteoblast apoptosis and reducing expression of factors that stimulate osteoblasts such as BMPs and growth factors.

Lower limb complications of diabetes mellitus: a comprehensive review with clinicopathological insights from a dedicated high-risk diabetic foot multidisciplinary team

Diabetic complications in the lower extremity are associated with significant morbidity and mortality, and impact heavily upon the public health system. Early and accurate recognition of these abnormalities is crucial, enabling the early initiation of treatments and thus avoiding or minimizing deformity, dysfunction and amputation. Following careful clinical assessment, radiological imaging is central to the diagnostic and follow-up process. We aim to provide a comprehensive review of diabetic lower limb complications designed to assist radiologists and to contribute to better outcomes for these patients.

Comparison of Bone Mineral Density, T-Scores and Serum Zinc between Diabetic and Non Diabetic Postmenopausal Women with Osteoporosis

CONTEXT

Postmenopausal osteoporosis is a public health problem. Diabetics are at increased risk of osteoporosis-related fractures. Zinc (Zn) has a role in collagen metabolism, and its levels are altered in diabetes.

AIMS

The aim was to compare bone mineral density (BMD), T-score and serum Zn between diabetic and nondiabetic postmenopausal women with osteoporosis to see if they influence increased fracture risk in diabetes.

SETTINGS AND DESIGN

It is a cross.sectional study conducted at Department of Biochemistry, Jawaharlal Nehru Medical College, Belgaum.

MATERIALS AND METHODS

Thirty type 2 diabetic and 30 age-matched (aged 45-75 years) nondiabetic Dual energy X-ray absorptiometry (DEXA) confirmed postmenopausal osteoporotics were included from January 2011 to March 2012. Serum Zn was analyzed by atomic absorption spectrophotometry.

STATISTICAL ANALYSIS USED

Mean and standard deviation of the parameters of the two groups were computed and compared by unpaired Student's t-test. Relationship between variables was measured by Karl Pearson's correlation co-efficient. A statistical significance is set at 5% level of significance (P < 0.05).

RESULTS

T-score was significantly higher in diabetics compared with nondiabetics (-2.84 ± 0.42 vs. -3.22 ± 0.74) P < 0.05. BMD and serum Zn of diabetics showed a significant positive correlation with body mass index (BMI).

CONCLUSIONS

Type 2 diabetic postmenopausal osteoporotics have a higher T-score than the nondiabetics. High BMI in type-2 diabetes mellitus (T2DM) may contribute to high BMD and may be a protective factor against zincuria. Increased fracture risk in T2DM could be due to other factors like poor bone quality due to hyperglycemia rather than BMD. Strict glycemic control is of paramount importance.

The prevention of fragility fractures in diabetic patients

Patients with diabetes mellitus (DM) are at greater risk of fractures mostly due to not only extraskeletal factors, such as propensity to falls, but also to bone quality alteration, which reduces bone strength. In people with DM, insulin deficit and hyperglycemia seem to play a role in determining bone formation alteration by AGE accumulation which directly influences osteoblast activity. Although there are conflicting data in the literature, adequate glycemic control with hypoglycemic treatment may be an important element in preventing bone tissue alterations in both type 1 and type 2 DM. Diabetes status is a predictive of future hip and major osteoporosis fractures independently of BMD and FRAX probability. Attention should be paid to the use of thiazolidinediones, especially in older women, because the direct negative effect on bone could exceed the positive effect of glycemic control. Systematic screening for complications and fall prevention efforts, along with calcium and vitamin D repletion and adequate physical activity, represents the mainstay of fracture prevention in DM patients. All anticatabolic drugs (raloxifene, bisphosphonates, denosumab) seem to be effective in DM patients. On the basis of pathophysiological evidence that suggests low bone formation in DM patients, osteoanabolic therapies such as teriparatide might represent an important therapeutic option for DM patients with severe osteoporosis and/or multiple fractures. The search for better methods for the identification of fragility fracture risk in the growing population of adult and elderly subjects with DM might be considered a clinical priority which could improve the prevention of fracture in DM patients.

A latent autoimmune diabetes in adults patient manifesting severe musculoskeletal complications

Patients with diabetes have many different kinds of complications involving multiple organs, but those involving the musculoskeletal system are relatively uncommon. Diabetic muscle infarction (DMI) is a rare, painful, and potentially serious condition in patients with poorly controlled diabetes mellitus. A 35-year-old man diagnosed with type 2 diabetes eight years ago, visited with severe muscle pain in the right anteromedial thigh without any event of trauma. He had been treated with metformin, but his glycemic control was very poor with a glycated hemoglobin of 14.5%. Evaluation of his painful thigh lesion did not reveal any evidence of infection or vasculitis, but the magnetic resonance imaging and bone scan showed findings of DMI at vastus medialis muscle and an insufficiency fracture at the right medial tibial condyle. He was diagnosed with retinopathy, neuropathy and microalbuminuria but not macrovascular complications. We also diagnosed his diabetes as latent autoimmune diabetes in adults (LADA) based on his low C-peptide level, positive anti-glutamic acid decarboxylase (GAD) antibody and early onset diabetes. Instead of antibiotics, bed rest, analgesics and strict blood glucose control with multiple daily insulin injections led to symptom improvement. This is an unusual case of a young man with LADA experiencing severe musculoskeletal complication of DMI and insufficiency fracture. If a poorly controlled diabetic patient appears to have unaccounted soft tissue pain, musculoskeletal complications such as DMI associated with hyperglycemia should be considered.

The Look AHEAD Trial: bone loss at 4-year follow-up in type 2 diabetes

OBJECTIVE

To determine whether an intensive lifestyle intervention (ILI) designed to sustain weight loss and improve physical fitness in overweight or obese persons with type 2 diabetes was associated with bone loss after 4 years of follow-up.

RESEARCH DESIGN AND METHODS

This randomized controlled trial of intensive weight loss compared an ILI with a diabetes support and education (DSE) group among 1,309 overweight or obese subjects. Bone mineral density was assessed at baseline and after 1 year and 4 years of intervention.

RESULTS

ILI was effective in producing significant weight loss (5.3% vs. 1.8% in ILI and DSE, respectively; P < 0.01) and increased fitness (6.4% vs. -0.8%) at year 4. In men, ILI participants had a greater rate of bone loss during the first year (-1.66% vs. -0.09% per year in ILI and DSE, respectively). Differences between groups were diminished by one-half after 4 years (-0.88% vs. -0.05% per year in ILI and DSE, respectively) but remained significant (P < 0.01). The difference in rate of hip bone loss between groups over 4 years was related to increased weight loss in ILI. Among women, the rate of bone loss did not differ between ILI and DSE after 4 years.

CONCLUSIONS

A 4-year weight loss intervention was significantly associated with a modest increase in bone loss at the hip in men but not in women.

Gender differences in sclerostin and clinical characteristics in type 1 diabetes mellitus

BACKGROUND

Sclerostin is an osteocyte-derived inhibitor of the Wnt/β-catenin signaling pathway, which acts as a negative regulator of bone formation. Published data on sclerostin levels in type 1 diabetes mellitus (T1DM) are few.

OBJECTIVE

To evaluate gender differences in sclerostin serum levels and the association among sclerostin, bone mass, bone metabolism, and the main clinical characteristics of subjects with T1DM.

DESIGN AND METHODS

A total of 69 patients with T1DM (mean age, 33.7±8.1; 49% males) were enrolled in this cross-sectional study in a clinical research center. Bone mineral density was measured by phalangeal quantitative ultrasound (QUS); bone turnover markers (urinary pyridinoline, deoxypyridinoline (D-PYR), and urine hydroxyproline (OH-PRO) to evaluate bone resorption; serum bone alkaline phosphatase and BGP to evaluate bone formation) and sclerostin were assessed.

RESULTS

D-PYR and sclerostin were significantly higher in women when compared with men (P=0.04). A disease duration >15 years was associated with higher sclerostin levels (P=0.03). Bone turnover markers and QUS parameters were not correlated with sclerostin. A significant negative correlation was observed among QUS parameters, BMI, and OH-PRO. Sclerostin serum levels were correlated with homocysteine (r=-0.34, P=0.005) and vitamin B12 (r=-0.31, P=0.02). Generalized linear model showed that macroangiopathy was the only predictor of sclerostin serum levels (β=-11.8, 95% CI from -21.9 to -1.7; P=0.02).

CONCLUSIONS

Our data demonstrate that women with T1DM exhibit higher sclerostin levels than men and that circulating sclerostin is not associated with bone turnover markers and phalangeal QUS measurements. Macroangiopathy was associated with sclerostin levels.

Osteocalcin levels are inversely associated with Hba1c and BMI in adult subjects with long-standing type 1 diabetes

PURPOSE

Diabetic osteopathy is an upcoming complication of diabetes characterized by osteoporosis, increased risk for bone fractures and alterations in bone metabolism. Osteocalcin (OC) is a bone-specific protein produced by osteoblasts involved in the regulation of glucose and energy metabolism. The aim of this study is to determine whether OC serum levels are correlated with metabolic control in adult subjects with type one diabetes mellitus (T1DM).

METHODS

A cross-sectional study was conducted on 93 subjects (51 men) with mean age, disease duration and body mass index (BMI) of 39.9 ± 12.3, 17.2 ± 12.6 years and 24.5 ± 3.4 kg/m(2), respectively. Blood samples were drawn to measure levels of hemoglobin A1c (HbA1c), OC, 25-OH vitamin D and PTH.

RESULTS

Significant inverse correlations were found between OC and HbA1c (r = -0.295, P = 0.004) and between OC and BMI (r = -0.218, P = 0.037). These correlations were confirmed also among men in the analyses by gender [HbA1c vs OC: r = -0.363, P = 0.009; BMI vs OC: r = -0.291, P = 0.043], and similar but nonsignificant trends were confirmed among women. A significant difference in mean OC was also found between the lowest and the highest HbA1c tertile (22.3 ± 10.0 vs 16.9 ± 8.0 ng/mL, P = 0.025).

CONCLUSIONS

These data show that in T1DM of long duration, OC serum levels are inversely associated with HbA1c and BMI, supporting the hypothesis that a poor glycemic control can affect osteoblast function.

Osteoporosis, fractures, and diabetes

It is well established that osteoporosis and diabetes are prevalent diseases with significant associated morbidity and mortality. Patients with diabetes mellitus have an increased risk of bone fractures. In type 1 diabetes, the risk is increased by ∼6 times and is due to low bone mass. Despite increased bone mineral density (BMD), in patients with type 2 diabetes the risk is increased (which is about twice the risk in the general population) due to the inferior quality of bone. Bone fragility in type 2 diabetes, which is not reflected by bone mineral density, depends on bone quality deterioration rather than bone mass reduction. Thus, surrogate markers and examination methods are needed to replace the insensitivity of BMD in assessing fracture risks of T2DM patients. One of these methods can be trabecular bone score. The aim of the paper is to present the present state of scientific knowledge about the osteoporosis risk in diabetic patient. The review also discusses the possibility of problematic using the study conclusions in real clinical practice.

Glycation: the angiogenic paradox in aging and age-related disorders and diseases

Angiogenesis is generally a quiescent process which, however, may be modified by different physiological and pathological conditions. The "angiogenic paradox" has been described in diabetes because this disease impairs the angiogenic response in a manner that differs depending on the organs involved and disease evolution. Aging is also associated with pro- and antiangiogenic processes. Glycation, the post-translational modification of proteins, increases with aging and the progression of diabetes. The effect of glycation on angiogenesis depends on the type of glycated proteins and cells involved. This complex link could be responsible for the "angiogenic paradox" in aging and age-related disorders and diseases. Using diabetes as a model, the present work has attempted to review the age-related angiogenic paradox, in particular the effects of glycation on angiogenesis during aging.

A genome-wide copy number association study of osteoporotic fractures points to the 6p25.1 locus

BACKGROUND

Osteoporosis is a systemic skeletal disease characterised by reduced bone mineral density and increased susceptibility to fracture; these traits are highly heritable. Both common and rare copy number variants (CNVs) potentially affect the function of genes and may influence disease risk.

AIM

To identify CNVs associated with osteoporotic bone fracture risk.

METHOD

We performed a genome-wide CNV association study in 5178 individuals from a prospective cohort in the Netherlands, including 809 osteoporotic fracture cases, and performed in silico lookups and de novo genotyping to replicate in several independent studies.

RESULTS

A rare (population prevalence 0.14%, 95% CI 0.03% to 0.24%) 210 kb deletion located on chromosome 6p25.1 was associated with the risk of fracture (OR 32.58, 95% CI 3.95 to 1488.89; p = 8.69 × 10(-5)). We performed an in silico meta-analysis in four studies with CNV microarray data and the association with fracture risk was replicated (OR 3.11, 95% CI 1.01 to 8.22; p = 0.02). The prevalence of this deletion showed geographic diversity, being absent in additional samples from Australia, Canada, Poland, Iceland, Denmark, and Sweden, but present in the Netherlands (0.34%), Spain (0.33%), USA (0.23%), England (0.15%), Scotland (0.10%), and Ireland (0.06%), with insufficient evidence for association with fracture risk.

CONCLUSIONS

These results suggest that deletions in the 6p25.1 locus may predispose to higher risk of fracture in a subset of populations of European origin; larger and geographically restricted studies will be needed to confirm this regional association. This is a first step towards the evaluation of the role of rare CNVs in osteoporosis.

Changes in Bone Mineral Density in Young Adults with Type 1 Diabetes Mellitus

Background and aims: Type 1 diabetes mellitus (T1DM) represents a secondary cause of osteoporosis. Our aim was to determine bone mineral density (BMD) changes in a group of young Romanian adults with T1DM and to analyze the factors related to this disease that could have had an impact on bone mass. Material and Methods: Fifty-two young patients with T1DM were compared to 37 healthy volunteers matched for body mass index (BMI). All subjects had their BMD measured at the hip and lumbar spine. Results: We found no statistically significant differences in BMD between T1DM patients and controls (p=0.618 for lumbar spine, p=0.974 for femoral neck and p=0.883 for total hip). Multiple linear regression models detected BMI (p =0.043), smoking (p=0.001) and milk intake (p=0.004 for lumbar spine) as significant BMD determinants. In contrast, no associations were found between BMD and metabolic control, daily insulin dose or presence of diabetic retinopathy and/or neuropathy. Long diabetes duration was negatively associated with BMD in femoral neck (p=0.012). Conclusions: Although we couldn’t find differences between BMD in T1DM patients and controls, the link between diabetes duration and BMD that we found suggests that even young patients with long standing T1DM should have their BMD measured

Biomolecular basis of the role of diabetes mellitus in osteoporosis and bone fractures

Osteoporosis has become a serious health problem throughout the world which is associated with an increased risk of bone fractures and mortality among the people of middle to old ages. Diabetes is also a major health problem among the people of all age ranges and the sufferers due to this abnormality increasing day by day. The aim of this review is to summarize the possible mechanisms through which diabetes may induce osteoporosis. Diabetes mellitus generally exerts its effect on different parts of the body including bone cells specially the osteoblast and osteoclast, muscles, retina of the eyes, adipose tissue, endocrine system specially parathyroid hormone (PTH) and estrogen, cytokines, nervous system and digestive system. Diabetes negatively regulates osteoblast differentiation and function while positively regulates osteoclast differentiation and function through the regulation of different intermediate factors and thereby decreases bone formation while increases bone resorption. Some factors such as diabetic neuropathy, reactive oxygen species, Vitamin D, PTH have their effects on muscle cells. Diabetes decreases the muscle strength through regulating these factors in various ways and ultimately increases the risk of fall that may cause bone fractures.