Diabetes and fractures: an overshadowed association

Three genes expressed in relation to lipid metabolism considered as potential biomarkers for the diagnosis and treatment of diabetic peripheral neuropathy

Diabetic neuropathy is one of the most common chronic complications and is present in approximately 50% of diabetic patients. A bioinformatic approach was used to analyze candidate genes involved in diabetic distal symmetric polyneuropathy and their potential mechanisms. GSE95849 was downloaded from the Gene Expression Omnibus database for differential analysis, together with the identified diabetic peripheral neuropathy-associated genes and the three major metabolism-associated genes in the CTD database to obtain overlapping Differentially Expressed Genes (DEGs). Gene Set Enrichment Analysis and Functional Enrichment Analysis were performed. Protein-Protein Interaction and hub gene networks were constructed using the STRING database and Cytoscape software. The expression levels of target genes were evaluated using GSE24290 samples, followed by Receiver operating characteristic, curve analysis. And Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on the target genes. Finally, mRNA-miRNA networks were constructed. A total of 442 co-expressed DEGs were obtained through differential analysis, of which 353 expressed up-regulated genes and 89 expressed down-regulated genes. The up-regulated DEGs were involved in 742 GOs and 10 KEGG enrichment results, mainly associated with lipid metabolism-related pathways, TGF-β receptor signaling pathway, lipid transport, and PPAR signaling pathway. A total of 4 target genes (CREBBP, EP300, ME1, CD36) were identified. Analysis of subject operating characteristic curves indicated that CREBBP (AUC = 1), EP300 (AUC = 0.917), ME1 (AUC = 0.944) and CD36 (AUC = 1) may be candidate serum biomarkers for DPN. Conclusion: Diabetic peripheral neuropathy pathogenesis and progression is caused by multiple pathways, which also provides clinicians with potential therapeutic tools.

TGF-beta pathway inhibition as the therapeutic acceleration of diabetic bone regeneration

Bone regeneration and fracture healing are impaired in diabetic patients due to defective functions of associated cells. Thus, the search for molecular causes and new treatment strategies are of particular clinical relevance. We investigated the gene expression profile of bones from type 2 diabetic (db^- /db^- ) mice and wild-type (wt) mice by comparative microarray analyses before and after placing tibial defects and examined the expression of several osteogenesis- and osteoclastogenesis-related markers by quantitative real-time polymerase chain reaction. In regenerating wt bones, pathways related to, for example, inhibition of matrix metalloproteases were activated, whereas in db^- /db^- bones activation of pathways related to, for example, osteoarthritis, transforming growth factor-beta (Tgfb), or hypoxia-inducible factor 1a were detected during regeneration. We defined the Tgfb pathway as a potential therapeutic target and locally applied a single dose (0.5 µg) of the Tgfb 1, 2, and 3 neutralizing antibody 1D11 on tibial defects in db^- /db^- mice (n = 7). Seven days postoperation, histological and immunohistochemical stainings were performed. Decreased bone regeneration, osteogenic differentiation, osteoclast invasion, and angiogenesis in db^- /db^- mice were significantly restored by local 1D11 application in comparison to the phosphate-buffered saline controls. Thus, local treatment of db^- /db^- bony defects with Tgfb neutralizing antibody 1D11 might be considered a good candidate for the successful acceleration of bone regeneration.

Increased postoperative glycemic variability is associated with increased mortality in diabetic patients undergoing hip arthroplasty for hip fracture

BACKGROUND

Increased glycemic variability (GV) during hospitalization has been associated with increased rates of surgical site and periprosthetic joint infections (PJI) following elective total joint arthroplasty. Uncertainty exists surrounding GV as a predictor for complications in urgent arthroplasty cases following hip fractures. In this study, we evaluated the association between GV and postoperative complications in diabetic patients undergoing total hip arthroplasty (THA) and hemiarthroplasty (HA) for hip fractures.

METHODS

We analyzed data on 2421 consecutive patients who underwent THA or HA at our institution from 2011 to 2020. Patients with a known diagnosis of diabetes mellitus who had a minimum of three postoperative glucose values taken within the first week after surgery were included. GV was assessed using a coefficient of variation. Outcomes included short- and long-term mortality, reoperations, prosthetic joint infection (PJI) requiring revision and readmissions for any cause.

RESULTS

The final cohort consisted of 482 patients (294 females, 188 males). Higher GV was associated with an increased 90-day mortality (p = 0.017). GV was not associated with 30-day mortality (p = 0.45), readmissions of any cause at 30 or 90 days (p = 0.99, p = 0.91, respectively), reoperation of any cause (p = 0.91) or PJI requiring revision surgery (p = 0.42).

CONCLUSIONS

Higher GV in the postoperative period is associated with increased rates of mortality in diabetic patients following THA and HA for hip fractures. Efforts should be made to monitor and control glucose variability in the postoperative period.

Free and Bioavailable Vitamin D Levels of Patients with Type 1 Diabetes Mellitus and Association with Bone Metabolism

Aim

Vitamin D deficiency is known to be associated with metabolic bone diseases. The aim of this study is to evaluate vitamin D and calculated free and bioactive vitamin D levels of type 1 diabetic patients and to evaluate the association with bone turnover markers.

Method

This cross-sectional study includes 60 patients admitted to endocrinology outpatient clinic with diagnosis of type 1 diabetes mellitus and 60 controls. Weight, height and waist circumference were recorded and blood samples were taken for measurement of 25-hydroxyvitamin D (25(OH)D), vitamin D binding protein (VDBP), osteocalcin, bone alkaline phosphatase (bone-ALP), c-telopeptide. Free and bioavailable vitamin D levels were calculated with formula.

Results

Vitamin D levels of type 1 diabetic patients were significantly higher (p = 0.01). Parathormone levels of the group with vitamin D level under 20 ng/ml was significantly higher (p = 0.029). VDBP levels were similar in both groups. Correlation analysis of free and bioavailable vitamin D level with osteocalcin, c-telopeptide, bone alkaline phosphatase revealed only a weak significant correlation between free vitamin D and osteocalcin (r = -0.201; p = 0.028). A negative correlation was determined between 25(OH)D and parathormone levels (r = -0.294; p < 0.005). Serum osteocalcin, bone alkaline phosphatase and c-telopeptide levels of control group were significantly higher.

Conclusion

25(OH)D levels of the study population was extremely low. The measurement of VDBP and calculated free and bioactive vitamin D levels did not show a better correlation with bone turnover markers according to 25(OH)D levels.

Effects of diet, BMP-2 treatment, and femoral skeletal injury on endothelial cells derived from the ipsilateral and contralateral limbs

Type 2 diabetes (T2D) results in physiological and structural changes in bone, contributing to poor fracture healing. T2D compromises microvascular performance, which can negatively impact bone regeneration as angiogenesis is required for new bone formation. We examined the effects of bone morphogenetic protein-2 (BMP-2) administered locally at the time of femoral segmental bone defect (SBD) surgery, and its angiogenic impacts on endothelial cells (ECs) isolated from the ipsilateral or contralateral tibia in T2D mice. Male C57BL/6 mice were fed either a low-fat diet (LFD) or high-fat diet (HFD) starting at 8 weeks. After 12 weeks, the T2D phenotype in HFD mice was confirmed via glucose and insulin tolerance testing and echoMRI, and all mice underwent SBD surgery. Mice were treated with BMP-2 (5 µg) or saline at the time of surgery. Three weeks postsurgery, bone marrow ECs were isolated from ipsilateral and contralateral tibias, and proliferation, angiogenic potential, and gene expression of the cells was analyzed. BMP-2 treatment increased EC proliferation by two fold compared with saline in LFD contralateral tibia ECs, but no changes were seen in surgical tibia EC proliferation. BMP-2 treatment enhanced vessel-like structure formation in HFD mice whereas, the opposite was observed in LFD mice. Still, in BMP-2 treated LFD mice, ipsilateral tibia ECs increased expression of CD31, FLT-1, ANGPT1, and ANGPT2. These data suggest that the modulating effects of T2D and BMP-2 on the microenvironment of bone marrow ECs may differentially influence angiogenic properties at the fractured limb versus the contralateral limb.

Inhibition of Pathological Increased Matrix Metalloproteinase (MMP) Activity for Improvement of Bone Regeneration in Diabetes

Patients with diabetes suffer from poor fracture healing. Molecular reasons are not fully understood and our previous gene expression microarray analyses of regenerating bones from mice with type 2 diabetes (db⁻/db⁻) revealed accelerated activation of pathways concerning matrix metalloproteases (MMPs). Thus, we picked out the pathological MMP acceleration as a target for profound gene expression analyses and additional therapeutic intervention in the present study. In the first part, gene expression of ECM degrading proteinases and inhibitors was investigated three and seven days postoperatively. Mmp3, Mmp9, Mmp13 and gene expression of MMP inhibitor Timp2 was significantly higher in regenerating bone fractures of db⁻/db⁻ compared to wild type animals. Timp1 and metalloproteinase AdamTS4 showed no differences. In the second part, we locally applied a single dose (1 µL of 5 µM solution) of the broad-spectrum molecular MMP inhibitor Marimastat on tibial defects in db⁻/db⁻. We performed immunohistochemical and histological stainings seven days post operation. Impaired bone healing, collagen content, angiogenesis, and osteoclast invasion in db⁻/db⁻ were restored significantly by application of Marimastat compared to PBS controls (n = 7/group). Hence, local intervention of bone defects by the molecular MMP inhibitor Marimastat might be an alternative therapeutic intervention for bone healing in diabetes.

Bone Density, Geometry, and Mass by Peripheral Quantitative Computed Tomography and Bone Turnover Markers in Children with Diabetes Mellitus Type 1

BACKGROUND

The type 1 diabetes mellitus (T1DM) is a chronic systemic autoimmune-mediated disease characterised by the insulin deficiency and hyperglycaemia. Its deleterious effect on bones concerns not only bone mass, density, and fracture risk but also may involve the linear growth of long bones. Studies on the lower leg in children with T1DM by pQCT have generated conflicting results, and most of the studies published so far focused only on a selected features of the bone. An additional information about growth, modelling, and remodelling processes can be gathered by the bone turnover marker measurement. The objective of the study was to evaluate bone mineral density, mass, and geometry using peripheral quantitative computed tomography as well as bone turnover markers in the patients with type 1 diabetes mellitus. Material and Methods. Bone mineral density, mass, and geometry on the lower leg using peripheral quantitative computed tomography and serum osteocalcin (OC) and carboxyterminal cross-linked telopeptide of type 1 collagen (CTx) were measured in 35 adolescents with T1DM (15 girls) aged 12.3-17.9 yrs. The results were compared to age- and sex-adjusted reference values for healthy controls.

RESULTS

Both sexes reveal lower than zero Z-scores for lower leg 66% total cortical bone cross-sectional area to muscle cross-sectional area ratio (-0.97 ± 1.02, p = 0.002517 and -0.98 ± 1.40, p = 0.007050, respectively) while tibia 4% trabecular bone density Z-score was lowered in boys (-0.67 ± 1.20, p = 0.02259). In boys in Tanner stage 5 bone mass and dimensions were diminished in comparison to Tanner stages 3 and 4, while in girls, such a phenomenon was not observed. Similarly, bone formation and resorption were decreased in boys but not in girls. Consistently, bone turnover markers correlated positively with bone size, dimensions, and strength in boys only.

CONCLUSIONS

T1DM patients revealed a decreased ratio of cortical bone area/muscle area, reflecting disturbed adaptation of the cortical shaft to the muscle force. When analyzing bone mass and dimensions, boys in Tanner stage 5 diverged from "less-mature" individuals, which may suggest that bone development in these individuals was impaired, affecting all three: mass, size, and strength. Noted in boys, suppressed bone metabolism may result in impairment of bone strength because of inadequate repair of microdamage and accumulation of microfractures.

Effect of Dipeptidyl Peptidase-4 Inhibitors on Bone Health in Patients with Type 2 Diabetes Mellitus

Patients with type 2 diabetes (T2DM) have a higher risk of bone fracture even when bone mineral density (BMD) values are normal. The trabecular bone score (TBS) was recently developed and used for evaluating bone strength in various diseases. We investigated the effect of DPP-4 inhibitors on bone health using TBS in patients with T2DM. This was a single-center, retrospective case-control study of 200 patients with T2DM. Patients were divided into two groups according to whether they were administered a DPP-4 inhibitor (DPP-4 inhibitor group vs. control group). Parameters related to bone health, including BMD, TBS, and serum markers of calcium homeostasis, were assessed at baseline and after one year of treatment. We found TBS values increased in the DPP-4 group and decreased in the control, indicating a significant difference in delta change between them. The BMD increased in both groups, with no significant differences in delta change between the two groups observed. Serum calcium and 25-hydroxy vitamin D3 increased only in the DPP-4 inhibitor group, while other glycemic parameters did not show significant differences between the two groups. Treatment with DPP-4 inhibitors was associated with favorable effects on bone health evaluated by TBS in patients with T2DM.

The Effects of Photobiomodulation on Bone Defect Repairing in a Diabetic Rat Model

The purpose of this study is to examine the prospective therapeutic effects of photobiomodulation on the healing of bone defects in diabetic mellitus (DM) using rat models to provide basic knowledge of photobiomodulation therapy (PBMT) during bone defect repair. For in vitro study, an Alizzarin red stain assay was used to evaluate the effect of PBMT on osteogenic differentiation. For in vivo study, micro-computed tomography (microCT) scan, H&E and IHC stain analysis were used to investigate the effect of PBMT on the healing of the experimental calvarial defect (3 mm in diameter) of a diabetic rat model. For in vitro study, the high glucose groups showed lower osteogenic differentiation in both irradiated and non-irradiated with PBMT when compared to the control groups. With the PBMT, all groups (control, osmotic control and high glucose) showed higher osteogenic differentiation when compared to the non-irradiated groups. For in vivo study, the hyperglycemic group showed significantly lower bone regeneration when compared to the control group. With the PBMT, the volume of bone regeneration was increasing and back to the similar level of the control group. The treatment of PBMT in 660 nm could improve the bone defect healing on a diabetic rat calvarial defect model.

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.

Hybrid deep learning model for risk prediction of fracture in patients with diabetes and osteoporosis

The fracture risk of patients with diabetes is higher than those of patients without diabetes due to hyperglycemia, usage of diabetes drugs, changes in insulin levels, and excretion, and this risk begins as early as adolescence. Many factors including demographic data (such as age, height, weight, and gender), medical history (such as smoking, drinking, and menopause), and examination (such as bone mineral density, blood routine, and urine routine) may be related to bone metabolism in patients with diabetes. However, most of the existing methods are qualitative assessments and do not consider the interactions of the physiological factors of humans. In addition, the fracture risk of patients with diabetes and osteoporosis has not been further studied previously. In this paper, a hybrid model combining XGBoost with deep neural network is used to predict the fracture risk of patients with diabetes and osteoporosis, and investigate the effect of patients' physiological factors on fracture risk. A total of 147 raw input features are considered in our model. The presented model is compared with several benchmarks based on various metrics to prove its effectiveness. Moreover, the top 18 influencing factors of fracture risks of patients with diabetes are determined.

Hydroxycoumarin Scopoletin Inhibits Bone Loss through Enhancing Induction of Bone Turnover Markers in a Mouse Model of Type 2 Diabetes

Diabetes induces bone deterioration, which leads to increased risk of fracture, osteopenia, and osteoporosis. Thus, diabetes-associated bone fragility has been recognized as a diabetic complication. However, the pathophysiological effects of hyperglycemia on bone turnover remain unclear. Literature evidence demonstrates that anti-diabetic medications increase the risk of fractures in individuals with type 2 diabetes. Scopoletin is a naturally occurring hydroxycoumarin potentially exhibiting anti-inflammatory and antioxidant activities and ameliorating insulin resistance as an anti-diabetic agent. However, little is known regarding the effects of scopoletin on the impairment of bone remodeling that is caused by diabetes. The aim of this study was to identify that scopoletin was capable of inhibiting the impairment of bone remodeling and turnover in a mouse model of type 2 diabetes. Submicromolar scopoletin accelerated the formation TRAP-positive multinucleated osteoclasts (40.0 vs. 105.1%) and actin ring structures impaired by 33 mM glucose. Further, 1–20 μM scopoletin enhanced bone resorption and the induction of matrix-degrading enzymes in diabetic osteoclasts. The oral administration of 10 mg/kg scopoletin elevated serum RANKL/OPG ratio and osteocalcin level reduced in db/db mice along with an increase in BMD by ~6–14%; however, it was not effective in lowering blood glucose and hemoglobin glycation. In addition, the supplementation of scopoletin elevated the formation of trabecular bones and collagen fibers in femoral epiphysis and metaphysis with a thicker epiphyseal plate and cortical bones. Furthermore, 1–20 μM scopoletin enhanced ALP activity (4.39 vs. 7.02 nmol p-nitrophenyl phosphate/min/mg protein) and deposits of mineralized bone nodules in cultured osteoblasts reduced by 33 mM glucose. The treatment of diabetic osteoblasts with scopoletin stimulated the cellular induction of BMP-2 and osteopontin and Runx2 transcription. Accordingly, the administration of scopoletin protected mice from type 2 diabetes-associated bone loss through boosting bone remodeling via the robust induction of bone turnover markers of both osteoclasts and osteoblasts. These findings suggest that scopoletin could be a potential osteoprotective agent for the treatment of diabetes-associated bone loss and fractures.

The effects of high fat diet, bone healing, and BMP-2 treatment on endothelial cell growth and function

Angiogenesis is a vital process during the regeneration of bone tissue. The aim of this study was to investigate angiogenesis at the fracture site as well as at distal locations from obesity-induced type 2 diabetic mice that were treated with bone morphogenetic protein-2 (BMP-2, local administration at the time of surgery) to heal a femoral critical sized defect (CSD) or saline as a control. Mice were fed a high fat diet (HFD) to induce a type 2 diabetic-like phenotype while low fat diet (LFD) animals served as controls. Endothelial cells (ECs) were isolated from the lungs (LECs) and bone marrow (BMECs) 3 weeks post-surgery, and the fractured femurs were also examined. Our studies demonstrate that local administration of BMP-2 at the fracture site in a CSD model results in complete bone healing within 3 weeks for all HFD mice and 66.7% of LFD mice, whereas those treated with saline remain unhealed. At the fracture site, vessel parameters and adipocyte numbers were significantly increased in BMP-2 treated femurs, irrespective of diet. At distal sites, LEC and BMEC proliferation was not altered by diet or BMP-2 treatment. HFD increased the tube formation ability of both LECs and BMECs. Interestingly, BMP-2 treatment at the time of surgery reduced tube formation in LECs and humeri BMECs. However, migration of BMECs from HFD mice treated with BMP-2 was increased compared to BMECs from HFD mice treated with saline. BMP-2 treatment significantly increased the expression of CD31, FLT-1, and ANGPT2 in LECs and BMECs in LFD mice, but reduced the expression of these same genes in HFD mice. To date, this is the first study that depicts the systemic influence of fracture surgery and local BMP-2 treatment on the proliferation and angiogenic potential of ECs derived from the bone marrow and lungs.

Assessment of risk factors for bone fractures in patients with type 2 diabetes mellitus: A study in Saudi Arabia

BACKGROUND AND AIMS

This study aimed to estimate the prevalence of bone fractures and analyze their associated risk factors in people with and without type 2 diabetes (T2D) in Saudi Arabia.

METHODS

This study was conducted among 1188 people (581 type 2 diabetes) in Prince Sultan Military Medical City, Riyadh, Saudi Arabia. In addition to the demographic variables, glycated hemoglobin (HbA1c), creatinine, estimated glomerular filtration rate (eGFR), use of teriparatide, presence of rheumatoid arthritis, presence of chronic obstructive pulmonary disease (COPD), Bone mineral density (BMD), Trabecular Bone Score (TBS) and Fracture Risk using the Fracture Risk Assessment Tool (FRAX) were also collected.

RESULTS

There were 1188 people (mean age 66.5 ± 8.7yrs) included in this study, of which 1068 (89.9%) were female, and 120 (10.1%) were male. A total of 112 (9.4%) individuals had a fracture history. Female, use of teriparatide, TBS (partially degraded and degraded), FRAX with TBS (MOF), and FRAX with TBS (Hip fx) were identified as independent risk factors for fracture in the whole study population. Teriparatide use and FRAX with TBS (MOF) were observed as independent risk factors for fracture in the non-diabetic population, whereas age, creatinine, eGFR, teriparatide, osteopenia, osteoporosis, TBS (partially degraded, degraded), FRAX with TBS (MOF), FRAX with TBS (Hip fx) were determined as independent risk factors for fracture among patients with diabetes.

CONCLUSION

Patients with T2D were observed to have a higher risk for fractures. The findings of the study highlight the requirement for fracture prevention strategies in patients with diabetes.

Microstructural and Strength Changes in Trabecular Bone in Elderly Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide and it is associated with an increased risk of osteoporosis and fragility fractures. Our aim is to analyze the effect of T2DM on bone quality. This is a case-control study. The studied population consisted of 140 patients: 54 subjects with hip fracture (OP) without T2DM, 36 patients with hip fracture and T2DM (OP-T2DM), 28 patients with osteoarthritis (OA) without T2DM, and 22 patients with OA and T2DM (OA-T2DM). Bone markers, bone mineral density, FRAX score, microstructural, and bone material strength from femoral heads were assessed. The group with hip fracture presented lower BMD values than OA (p < 0.05). The OP, OP-T2DM, and OA-T2DM groups showed a decrease in bone volume fraction (BV/TV), in trabecular number (Tb.N), and in trabecular thickness (Tb.Th), while an increase was presented in the structural model index (SMI) and trabecular bone pattern factor (Tb.Pf), The groups OP, OP-T2DM, and OA-T2DM also presented lower values than those in group OA regarding the biomechanical parameters in the form of Young’s modulus or elastic modulus, toughness, ultimate stress, ultimate load, extrinsic stiffness, and work to failure (p < 0.05). Our results show the negative effect of type 2 diabetes mellitus on trabecular bone structure and mechanical properties.

Functionally engineered extracellular vesicles improve bone regeneration

Lineage specific differentiation of host mesenchymal stem cells (MSCs) is a necessary step for bone repair/regeneration. Clinically, growth factors such as bone morphogenetic protein 2 (BMP2) are used to enhance/hasten this process to heal critical sized defects. However, the clinical application of such growth factors is fraught with dosage challenges as well as immunological and ectopic complications. The identification of extracellular vesicles (EVs) as active components of the MSC secretome suggest alternative approaches to enhancing bone regeneration. Based on our earlier studies on the properties of EVs from lineage specified MSCs, this study sought to engineer EVs to enhance osteogenic differentiation. To generate MSC EVs with enhanced osteoinductive abilities, genetically modified human bone marrow derived MSCs (HMSCs) were generated by constitutively expressing BMP2. We hypothesized that these cells would generate functionally engineered EVs (FEEs) with enhanced osteoinductive properties. Our results show that these FEEs maintained the general physical and biochemical characteristics of naïve HMSC EVs in the form of size distribution, EV marker expression and endocytic properties but show increased bone regenerative potential compared to MSC EVs in a rat calvarial defect model in vivo. Mechanistic studies revealed that although BMP2 was constitutively expressed in the parental cells, the corresponding EVs (FEEs) do not contain BMP2 protein as an EV constituent. Further investigations revealed that the FEEs potentiate the BMP2 signaling cascade possibly due to an altered miRNA composition. Collectively, these studies indicate that EVs' functionality may be engineered by genetic modification of the parental MSCs to induce osteoinduction and bone regeneration. SIGNIFICANCE STATEMENT: With mounting evidence for the potential of MSC EVs in treatment of diseases and regeneration of tissues, it is imperative to evaluate if they can be modified for application specificity. The results presented here indicate the possibility for generating Functionally Engineered EVs (FEEs) from MSC sources. As a proof of concept approach, we have shown that EVs derived from genetically modified MSCs (BMP2 overexpression) can be effective as biomimetic substitutes for growth factors for enhanced tissue-specific regeneration (bone regeneration) in vivo. Mechanistic studies highlight the role of EV miRNAs in inducing pathway-specific changes. We believe that this study will be useful to researchers evaluating EVs for regenerative medicine applications.

The effect of diabetes on functional outcomes among individuals with distal radial fractures

STUDY DESIGN

Prospective cohort study.

INTRODUCTION

Diabetes is reported to adversely affect outcomes; however, its effect on distal radial fractures (DRF) is not well examined.

PURPOSE OF THE STUDY

This study investigated the effect of diabetes on pain, hand function, physical health status, grip strength, and wrist and forearm range of motion among patients with DRF.

METHODS

A total of 479 patients with DRF were classified into patients with and without diabetes based on self-report. Patient-Rated Wrist Evaluation assessed pain and hand function. The Short Form-12 assessed physical health status. Both questionnaires examined DRF recovery at baseline, 3 month, and 1 year.

RESULTS

There was a significant improvement in Patient-Rated Wrist Evaluation scores over time (69 [19] to 25 [22]; 76 [15] to 20 [20] for patients with and without diabetes respectively, P < .01) with a significant interaction between time and diabetes (P < .01), indicating that patients with diabetes recovered more slowly than the rest of the cohort. There was an improvement over time on physical status (36 [12] to 45 [12]; 39 [9] to 50 [9], P < .01), grip strength (16 [7] to 24 [10]; 15 [9] to 24 [10], P < .01), and range of motion (flexion [42 {14} to 49 {15}; 43 {15} to 54 {14}, P < .01], extension [45 {11} to 52 {11}; 46 {13} to 53 {12}, P < .01], pronation [73 {10} to 77 {9}; 73 {11} to 78 {9}, P < .01], and supination [58 {17} to 65 {14}; 61 {17} to 70 {12}, P < .01]) for patients with and without diabetes, respectively. Patients with diabetes did not differ significantly in these secondary outcomes compared to the rest of the cohort.

DISCUSSION AND CONCLUSION

Although individuals with diabetes had good outcomes, their recovery was slower than the rest of the cohort. This may be due to the adverse effect of hyperglycemia on bone tissues and small blood vessels. Future studies are required to assess how severity and duration of diabetes affect outcomes after DRF.

The CANVAS Program: implications of canagliflozin on reducing cardiovascular risk in patients with type 2 diabetes mellitus

Canagliflozin is a sodium glucose co-transporter 2 (SGLT2) inhibitor that reduces blood glucose, as well as blood pressure, body weight, and albuminuria in patients with type 2 diabetes mellitus (T2DM). In the CANagliflozin cardioVascular Assessment Study (CANVAS) Program, patients with T2DM and high cardiovascular risk treated with canagliflozin had a significantly lower risk of the composite outcome of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke; hospitalization for heart failure; and renal outcomes, but also a greater risk of lower-limb amputation. Cardiovascular outcomes trials of some other T2DM agents (i.e., empagliflozin, dapagliflozin, liraglutide, semaglutide, albiglutide) have also shown potential cardiovascular and renal benefits. As a result, diabetes treatment guidelines have begun to incorporate consideration of cardiovascular and renal benefits into their treatment recommendations. Antihyperglycemic agents with proven beneficial cardiovascular effects represent a new opportunity for the diabetologist and cardiologist, in the setting of a multidisciplinary approach, to concomitantly improve glycemic control and reduce the risk of cardiovascular events in patients with T2DM. This review briefly discusses the pharmacology of canagliflozin, including clinical and preclinical data; it also describes the effects of canagliflozin on cardiovascular outcomes and side-effects, and compares these effects with other glucose-lowering agents with proven cardiovascular benefits.

Shear wave elastography evaluation of the median and tibial nerve in diabetic peripheral neuropathy

Background

To evaluate the value of shear wave elastography (SWE) in the detection of diabetic peripheral neuropathy (DPN) of the median and tibial nerves.

Methods

The study included 40 DPN patients, 40 diabetic mellitus (DM) patients without DPN, and 40 healthy subjects. High-resolution ultrasonography (US) and SWE were performed on the median nerve (MN) and tibial nerve (TN), and cross-sectional area (CSA) and nerve stiffness were measured. ROC analysis was also performed.

Results

The patients with DPN demonstrated higher stiffness of the median and tibial nerve compared with that of healthy volunteers and DM patients (P<0.001). Bilateral analysis showed that there was no significant difference in nerve stiffness between the left and right median nerves and tibial nerves in DPN patients (P>0.05). The stiffness of median nerve and tibial nerve in each one side also had no significant difference in patients with DPN (P>0.05). The CSA of the tibial nerve in the DPN group was significantly larger than that in the other groups (P<0.001), while there was no significant difference of median nerve CSA among the three groups (P>0.05). The area under curve (AUC) of SWE (MN: 0.899, TN: 0.927) to diagnose DPN was significantly greater than that of CSA (TN: 0.798). The optimal cut-off value in SWE of the tibial nerve and median nerve for diagnosis of DPN was 4.11 and 4.06 m/s, respectively, with a good sensitivity and specificity.

Conclusions

Median and tibial nerve stiffness was significantly higher in patients with DPN. These findings suggest that SWE-based stiffness measurement of the nerve was a better method than CSA, and it can be used as another effective assistant method in the diagnosis of DPN.

Assessing the economic value of maintained improvements in Type 1 diabetes management, in terms of HbA1c , weight and hypoglycaemic event incidence

AIMS

Insulin therapy is indicated for people with Type 1 diabetes mellitus; however, treatment-related weight gain and hypoglycaemia represent barriers to optimal glycaemic management. This study assessed the health economic value of maintained reductions in HbA_1c , BMI and hypoglycaemia incidence among the UK Type 1 diabetes population.

METHODS

The Cardiff Type 1 Diabetes Model was used to estimate lifetime costs, life-years and quality-adjusted life-years (QALYs) for individuals with Type 1 diabetes at different baseline HbA_1c , BMI and hypoglycaemic event rates. Results were discounted at 3.5%, and the net monetary benefit associated with improving Type 1 diabetes management was derived at £20 000/QALY gained. Per-person outputs were inflated to national levels using UK Type 1 diabetes prevalence estimates.

RESULTS

Modelled subjects with an HbA_1c of 86 mmol/mol (10.0%) were associated with discounted lifetime per-person costs of £23 795; £12 649 of which may be avoided by maintaining an HbA_1c of 42 mmol/mol (6.0%). Combined with estimated QALY gains of 2.80, an HbA_1c of 42 mmol/mol (6.0%) vs. 86 mmol/mol (10.0%) was associated with a £68 621 per-person net monetary benefit. Over 1 year, unit reductions in BMI produced £120 per-person net monetary benefit, and up to £197 for the avoidance of one non-severe hypoglyceamic event.

CONCLUSIONS

Maintained reductions in HbA_1c significantly alleviate the burden associated with Type 1 diabetes in the UK. Given the influence of weight and hypoglycaemia on health economic outcomes, they must also be key considerations when assessing the value of Type 1 diabetes technologies in clinical practice.

Pulsed electromagnetic field stimulation may improve fusion rates in cervical arthrodesis in high-risk populations

OBJECTIVES

Pulsed electromagnetic field (PEMF) stimulation was evaluated after anterior cervical discectomy and fusion (ACDF) procedures in a randomized, controlled clinical study performed for United States Food and Drug Administration (FDA) approval. PEMF significantly increased fusion rates at six months, but 12-month fusion outcomes for subjects at elevated risk for pseudoarthrosis were not thoroughly reported. The objective of the current study was to evaluate the effect of PEMF treatment on subjects at increased risk for pseudoarthrosis after ACDF procedures.

METHODS

Two evaluations were performed that compared fusion rates between PEMF stimulation and a historical control (160 subjects) from the FDA investigational device exemption (IDE) study: a post hoc (PH) analysis of high-risk subjects from the FDA study (PH PEMF); and a multicentre, open-label (OL) study consisting of 274 subjects treated with PEMF (OL PEMF). Fisher's exact test and multivariate logistic regression was used to compare fusion rates between PEMF-treated subjects and historical controls.

RESULTS

In separate comparisons of PH PEMF and OL PEMF groups to the historical control group, PEMF treatment significantly (p < 0.05, Fisher's exact test) increased the fusion rate at six and 12 months for certain high-risk subjects who had at least one clinical risk factor of being elderly, a nicotine user, osteoporotic, or diabetic; and for those with at least one clinical risk factor and who received at least a two- or three-level arthrodesis.

CONCLUSION

Adjunctive PEMF treatment can be recommended for patients who are at high risk for pseudoarthrosis.Cite this article: D. Coric, D. E. Bullard, V. V. Patel, J. T. Ryaby, B. L. Atkinson, D. He, R. D. Guyer. Pulsed electromagnetic field stimulation may improve fusion rates in cervical arthrodesis in high-risk populations. Bone Joint Res 2018;7:124-130. DOI: 10.1302/2046-3758.72.BJR-2017-0221.R1.

The effect of insulin on bone mineral density among women with type 2 diabetes: a SWAN Pharmacoepidemiology study

This was a longitudinal study examining the effects of insulin use on bone mineral density loss. Insulin use was found to be associated with greater bone mineral density loss at the femoral neck among women with diabetes mellitus.

INTRODUCTION

Women with diabetes mellitus (DM) have higher bone mineral density (BMD) and experience slower BMD loss but have an increased risk of fracture. The data regarding the effect of insulin treatment on BMD remains conflicted. We examined the impact of insulin initiation on BMD.

METHODS

We investigated the annual changes in BMD associated with the new use of insulin among women with DM in the Study of Women's Health Across the Nation (SWAN). Propensity score (PS) matching, which is a statistical method that helps balance the baseline characteristics of women who did and did not initiate insulin, was used. Covariates with a potential impact on bone health were included in all models. Mixed model regression was used to test the change in BMD between the two groups. Median follow-up time was 5.4 years.

RESULTS

The cohort consisted of 110 women, mean age, 53.6 years; 49% white and 51% black. Women using insulin (n = 55) were similar on most relevant characteristics to the 55 not using insulin. Median diabetes duration for the user group was 10 vs. 5.0 years for the non-user group. There was a greater loss of BMD at the femoral neck among insulin users (- 1.1%) vs non-users (- 0.77%) (p = 0.04). There were no differences in BMD loss at the spine - 0.30% vs - 0.32% (p = 0.85) or at the total hip - 0.31% vs - 0.25 (p = 0.71), respectively.

CONCLUSIONS

Women with T2DM who initiated insulin experienced a more rapid BMD loss at the femoral neck as compared to women who did use insulin.

The changing epidemiology of fall-related fractures in adults

There has been very little analysis of the epidemiology of adult fall-related fractures outwith the osteoporotic population. We have analysed all in-patient and out-patient fall-related fractures in a one-year period in a defined population and documented their epidemiology. The overall prevalence of non-spinal fall-related fractures is 63.1% with 40.7% and 82.7% occurring in males and females respectively. In females aged 20-29 years >50% of fractures follow falls, the equivalent age range in males being 50-59 years. Analysis of fall-related fractures in two one-year periods in 2000 and 2010/11 shows a significant increase in almost all age ranges up to 60-69 years with a decreased incidence in 90+ patients. In males there is a significant increase in 30-39year males but also in males >80years. In females the greatest increase in incidence is in 16-19year females but all age ranges show a significant increase up to 60-69 years. There is a decreased incidence in 90+ females. The reasons for the increase in the incidence of fall-related are multifactorial but they are probably contributed to by the inherently weaker bone of younger females and by the increased incidence of conditions such as obesity and diabetes.

Diabetes and disordered bone metabolism (diabetic osteodystrophy): time for recognition

Diabetes and osteoporosis are rapidly growing diseases. The link between the high fracture incidence in diabetes as compared with the non-diabetic state has recently been recognized. While this review cannot cover every aspect of diabetic osteodystrophy, it attempts to incorporate current information from the First International Symposium on Diabetes and Bone presentations in Rome in 2014. Diabetes and osteoporosis are fast-growing diseases in the western world and are becoming a major problem in the emerging economic nations. Aging of populations worldwide will be responsible for an increased risk in the incidence of osteoporosis and diabetes. Furthermore, the economic burden due to complications of these diseases is enormous and will continue to increase unless public awareness of these diseases, the curbing of obesity, and cost-effective measures are instituted. The link between diabetes and fractures being more common in diabetics than non-diabetics has been widely recognized. At the same time, many questions remain regarding the underlying mechanisms for greater bone fragility in diabetic patients and the best approach to risk assessment and treatment to prevent fractures. Although it cannot cover every aspect of diabetic osteodystrophy, this review will attempt to incorporate current information particularly from the First International Symposium on Diabetes and Bone presentations in Rome in November 2014.

Local Application of Isogenic Adipose-Derived Stem Cells Restores Bone Healing Capacity in a Type 2 Diabetes Model

Bone regeneration is typically a reliable process without scar formation. The endocrine disease type 2 diabetes prolongs and impairs this healing process. In a previous work, we showed that angiogenesis and osteogenesis-essential steps of bone regeneration-are deteriorated, accompanied by reduced proliferation in type 2 diabetic bone regeneration. The aim of the study was to improve these mechanisms by local application of adipose-derived stem cells (ASCs) and facilitate bone regeneration in impaired diabetic bone regeneration. The availability of ASCs in great numbers and the relative ease of harvest offers unique advantages over other mesenchymal stem cell entities. A previously described unicortical tibial defect model was utilized in diabetic mice (Lepr(db-/-)). Isogenic mouse adipose-derived stem cells (mASCs)(db-/db-) were harvested, transfected with a green fluorescent protein vector, and isografted into tibial defects (150,000 living cells per defect). Alternatively, control groups were treated with Dulbecco's modified Eagle's medium or mASCs(WT). In addition, wild-type mice were identically treated. By means of immunohistochemistry, proteins specific for angiogenesis, cell proliferation, cell differentiation, and bone formation were analyzed at early (3 days) and late (7 days) stages of bone regeneration. Additionally, histomorphometry was performed to examine bone formation rate and remodeling. Histomorphometry revealed significantly increased bone formation in mASC(db-/db-)-treated diabetic mice as compared with the respective control groups. Furthermore, locally applied mASCs(db-/db-) significantly enhanced neovascularization and osteogenic differentiation. Moreover, bone remodeling was upregulated in stem cell treatment groups. Local application of mACSs can restore impaired diabetic bone regeneration and may represent a therapeutic option for the future.

SIGNIFICANCE

This study showed that stem cells obtained from fat pads of type 2 diabetic mice are capable of reconstituting impaired bone regeneration in type 2 diabetes. These multipotent stem cells promote both angiogenesis and osteogenesis in type 2 diabetic bony defects. These data might prove to have great clinical implications for bony defects in the ever-increasing type 2 diabetic patient population.

Correlations Between Abnormal Glucose Metabolism and Bone Mineral Density or Bone Metabolism

Background

The aim of this meta-analysis was to explore the correlations of abnormal glucose metabolism (AGM) with bone mineral density (BMD) and bone metabolism.

Material/Methods

Relevant studies were identified using computerized and manual search strategies. The included studies were in strict accordance with inclusion and exclusion criteria. Statistical analyses were conducted with the Comprehensive Meta-analysis 2.0 (Biostat Inc., Englewood, NJ, USA).

Results

Our present meta-analysis initially searched 844 studies, and 7 studies were eventually incorporated in the present meta-analysis. These 7 cohort studies included 1123 subjects altogether (560 patients with AGM and 563 healthy controls). The results showed that bone mass index (BMI), insulin, and insulin resistance (IR) of patients with AGM were significantly higher than that of the population with normal glucose metabolism (BMI: SMD=1.658, 95% CI=0.663~2.654, P=0.001; insulin: SMD=0.544, 95% CI=0.030~1.058, P=0.038; IR: SMD=8.767, 95% CI=4.178~13.356, P<0.001). However, the results also indicated there was no obvious difference in osteocalcin (OC) and BMD in patients with AGM and the population with normal glucose metabolism (OC: SMD=0.293, 95% CI=−0.023~0.609, P=0.069; BMD: SMD=0.805, 95% CI=−0. 212~1.821, P=0.121).

Conclusions

Our meta-analysis results suggest that AGM might lead to increased BMI, insulin, and IR, while it has no significant correlation with BMD or bone metabolism.

Effects of Canagliflozin on Fracture Risk in Patients With Type 2 Diabetes Mellitus

CONTEXT

Canagliflozin is a sodium glucose cotransporter 2 inhibitor developed to treat type 2 diabetes mellitus (T2DM).

OBJECTIVE

The purpose of this study was to describe the effects of canagliflozin on bone fracture risk.

DESIGN AND SETTING

This was a randomized phase 3 study in patients with T2DM.

PATIENTS AND INTERVENTIONS

Canagliflozin doses of 100 and 300 mg were evaluated in the overall population of patients from 9 placebo- and active-controlled studies (N = 10 194), as well as in separate analyses of a single trial enriched with patients with a prior history/risk of cardiovascular disease (ie, the CANagliflozin cardioVascular Assessment Study [CANVAS]; N = 4327) and a pooled population of 8 non-CANVAS studies (N = 5867).

OUTCOME MEASURES

The incidence of adjudicated fracture adverse events (AEs), fall-related AEs, and volume depletion-related AEs was assessed.

RESULTS

The incidence of fractures was similar with canagliflozin (1.7%) and noncanagliflozin (1.5%) in the pooled non-CANVAS studies. In CANVAS, a significant increase in fractures was seen with canagliflozin (4.0%) vs placebo (2.6%) that was balanced between the upper and lower limbs. The incidence of fractures was higher with canagliflozin (2.7%) vs noncanagliflozin (1.9%) in the overall population, which was driven by the increase of fractures in CANVAS. The incidence of reported fall-related AEs was low, but significantly higher with canagliflozin in CANVAS, potentially related to volume depletion-related AEs, but not significantly different in the pooled non-CANVAS studies and the overall population.

CONCLUSIONS

Fracture risk was increased with canagliflozin treatment, driven by CANVAS patients, who were older, with a prior history/risk of cardiovascular disease, and with lower baseline estimated glomerular filtration rate and higher baseline diuretic use. The increase in fractures may be mediated by falls; however, the cause of increased fracture risk with canagliflozin is unknown.

Is Zolpidem Associated with Increased Risk of Fractures in the Elderly with Sleep Disorders? A Nationwide Case Cross-Over Study in Taiwan

Background

We conducted a study using a case-crossover design to clarify the risk of acute effects of zolpidem and benzodiazepine on all-sites of fractures in the elderly.

Design of study

Case-crossover design.

Methods and Materials

Elderly enrollees (n = 6010) in Taiwan’s National Health Insurance Research Database with zolpidem or benzodiazepine use were analyzed for the risk of developing fractures.

Results

After adjusting for medications such as antipsychotics, antidepressants, and diuretics, or comorbidities such as hypertension, osteoarthritis, osteoporosis, rheumatoid arthritis and depression, neither zolpidem nor benzodiazepine was found to be associated with increased risk in all-sites fractures. Subjects without depression were found to have an increased risk of fractures. Diazepam is the only benzodiazepine with increased risk of fractures after adjusting for medications and comorbidities. Hip and spine were particular sites for increased fracture risk, but following adjustment for comorbidities, the associations were found to be insignificant.

Conclusion

Neither zolpidem nor benzodiazepine was associated with increased risk of all-site fractures in this case cross-over study after adjusting for medications or comorbidities in elderly individuals with insomnia. Clinicians should balance the benefits and risks for prescribing zolpidem or benzodiazepine in the elderly accordingly.

Effect of exenatide, insulin and pioglitazone on bone metabolism in patients with newly diagnosed type 2 diabetes

AIM

Preclinical studies suggested that insulin, incretin and thiazolidinediones had effect on regulation of bone metabolism. But clinical evidence is limited. We assessed the effects of these antihyperglycemic agents on bone metabolism in patients with newly diagnosed type 2 diabetes.

METHODS

The present study was a two-center, randomized, parallel-group clinical trial. Sixty-two newly diagnosed and drug-naïve patients with type 2 diabetes were randomized to exenatide (EXE, n = 20), mixed protamine zinc recombinant human insulin lispro injection (25R; INS, n = 21) or pioglitazone (PIO, n = 21) group for a 24-week treatment. Glycosylated hemoglobin A1c (HbA1c), body weight, body mineral density (BMD) and fasting serum concentration of bone turnover markers including osteocalcin (OC), C-telopeptide of type I collagen (CTX) and tartrate-resistant alkaline phosphatase 5b (TRAcP5b) were assessed at baseline and week 24.

RESULTS

Baseline characteristics were similar among groups. At week 24, HbA1c improved in all patients (EXE:-2.4 ± 0.3 %, INS:-2.4 ± 0.3 %, PIO:-2.0 ± 0.2 %; p > 0.05 among groups). Patients treated with exenatide lost body weight remarkably (-4.7 ± 0.8 kg). In spite of the amelioration of glucose control, no significant improvement of OC, CTX or TRAcP5b was observed at week 24 (EXE: OC -0.619 ± 0.728 ng/ml, CTX 0.147 ± 0.046 ng/ml, TRAcP5b 0.302 ± 0.149 U/L;INS: OC 0.637 ± 0.787 ng/ml, CTX -0.012 ± 0.074 ng/ml, TRAcP5b 0.124 ± 0.395 U/L; PIO: OC -0.150 ± 0.691 ng/ml, CTX 0.073 ± 0.094 ng/ml, TRAcP5b 0.586 ± 0.183 U/L; p > 0.05), as well as BMD measurement, regardless of the treatments.

CONCLUSIONS

Twenty-four-week treatment with exenatide, insulin and pioglitazone improved glucose control in patients with newly diagnosed type 2 diabetes, but had no impact on bone turnover markers or BMD.

Prospective, Multicenter Evaluation of Allogeneic Bone Matrix Containing Viable Osteogenic Cells in Foot and/or Ankle Arthrodesis

BACKGROUND

Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses.

METHODS

A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively.

RESULTS

At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvements in pain, function, and QOL were observed, and fusion correlated with both function and QOL outcomes at 6 and 12 months. There were no adverse events attributable to CBA.

CONCLUSION

Fusion rates using CBA were higher than or comparable to fusion rates with autograft that have been reported in the recent literature, and CBA fusion rates were not adversely affected by several high-risk patient factors. CBA was a safe and effective graft material to achieve fusion in patients with compromised bone healing and may provide an effective autograft replacement for foot and/or ankle arthrodeses.

LEVEL OF EVIDENCE

Level II, prospective study.

Glycemic Control with Thiazolidinedione Is Associated with Fracture of T2DM Patients

Objective

Diabetes is a common diseases and a major problem worldwide. Diabetic osteopathy might be elevated in diabetic patients and is usually caused by bone fracture. Several diabetes medications, such as thiazolidinediones (TZDs), could lead to increased risks of fracture.

Methods

We used the nationwide database to identified 32466 patients who had developed type 2 diabetes from 2000 to 2010 as the diabetic cohort and, from that group, we selected 3427 diabetic patients who had developed bone fracture to survey the possible risk factors, includng commonly used diabetes medication.

Results

We found that TZDs might present increased risks for fracture in patients who used it for an extended period (7 to 730 days before the index date), especially in female patients younger than 64 years old, for whom the risk was elevated from a 1.74- to a 2.58-fold odds ratio.

Conclusions

We recommend that clinics follow up with non-osteoporotic female patients younger than 64 years old who are using TZDs, to avoid the associated risks of fracture.

B-vitamins and bone health--a review of the current evidence

Because of ongoing global ageing, there is a rapid worldwide increase in incidence of osteoporotic fractures and the resultant morbidity and mortality associated with these fractures are expected to create a substantial economic burden. Dietary modification is one effective approach for prevention of osteoporosis in the general population. Recently, B vitamins have been investigated for their possible roles in bone health in human studies. In this review, we provide different lines of evidence and potential mechanisms of individual B vitamin in influencing bone structure, bone quality, bone mass and fracture risk from published peer-reviewed articles. These data support a possible protective role of B vitamins, particularly, B2, B6, folate and B12, in bone health. However, results from the clinical trials have not been promising in supporting the efficacy of B vitamin supplementation in fracture reduction. Future research should continue to investigate the underlying mechanistic pathways and consider interventional studies using dietary regimens with vitamin B enriched foods to avoid potential adverse effects of high-dose vitamin B supplementation. In addition, observational and interventional studies conducted in Asia are limited and thus require more attention due to a steep rise of osteoporosis and hip fracture incidence projected in this part of the world.

Different health behaviours and clinical factors associated with bone mineral density and bone turnover in premenopausal women with and without type 1 diabetes

BACKGROUND

Women with type 1 diabetes (T1DM) have an elevated fracture risk. We therefore compared the associations of health behaviours and clinical factors with bone mineral density (BMD) and bone remodelling between premenopausal women with and without T1DM to inform potential interventions.

METHODS

Participants included women with T1DM (n = 89) from the Wisconsin Diabetes Registry Study and age-matched and race-matched controls without diabetes (n = 76). Peripheral (heel and forearm) and central (hip and spine) BMD, markers of bone resorption and formation, bone cell signalling, glycaemic control, and kidney function were assessed. Health behaviours and medical history were self-reported.

RESULTS

In controls, but not in women with T1DM, older age was associated with lower bone resorption (p ≤ 0.006) and formation (p = 0.0007). Body mass index was positively associated with heel and forearm BMD in both controls and T1DM women (all p < 0.0001), but with hip and spine BMD only in controls (p ≤ 0.005). Worse glycaemic control during the previous 10 years, greater alcohol intake, history of smoking, and lack of physical activity were associated with poorer bone outcomes only in women with T1DM (all p ≤ 0.002), whereas use of hormonal contraceptives was related to low bone formation in both women with and without T1DM (all p ≤ 0.006). Diabetes duration, insulin dose, residual C-peptide, and kidney function were not associated with bone in T1DM.

CONCLUSIONS

Age and body mass index may not predict bone health in T1DM women. However, modifiable behaviours such as optimizing glycaemic control, limiting substance and hormonal contraceptive use, and increasing physical activity may improve bone health in T1DM women.

Application of VEGFA and FGF-9 enhances angiogenesis, osteogenesis and bone remodeling in type 2 diabetic long bone regeneration

Although bone regeneration is typically a reliable process, type 2 diabetes is associated with impaired or delayed healing processes. In addition, angiogenesis, a crucial step in bone regeneration, is often altered in the diabetic state. In this study, different stages of bone regeneration were characterized in an unicortical bone defect model comparing transgenic type 2 diabetic (db^-/db^-) and wild type (WT) mice in vivo. We investigated angiogenesis, callus formation and bone remodeling at early, intermediate and late time points by means of histomorphometry as well as protein level analyses. In order to enhance bone regeneration, defects were locally treated with recombinant FGF-9 or VEGFA. Histomorphometry of aniline blue stained sections indicated that bone regeneration is significantly decreased in db^-/db^- as opposed to WT mice at intermediate (5 days post operation) and late stages (7 days post operation) of bone regeneration. Moreover, immunohistochemical analysis revealed significantly decreased levels of RUNX-2, PCNA, Osteocalcin and PECAM-1 in db^-/db^- defects. In addition, osteoclastogenesis is impaired in db^-/db^- indicating altered bone remodeling. These results indicate significant impairments in angiogenesis and osteogenesis in type 2 diabetic bones. Importantly, angiogenesis, osteogenesis and bone remodeling could be reconstituted by application of recombinant FGF-9 and, in part, by VEGFA application. In conclusion, our study demonstrates that type 2 diabetes affects angiogenesis, osteogenesis and subsequently bone remodeling, which in turn leads to decreased bone regeneration. These effects could be reversed by local application of FGF-9 and to a lesser degree VEGFA. These data could serve as a basis for future therapeutic applications aiming at improving bone regeneration in the type 2 diabetic patient population.

Diabetes reduces mesenchymal stem cells in fracture healing through a TNFα-mediated mechanism

AIMS/HYPOTHESIS

Diabetes interferes with bone formation and impairs fracture healing, an important complication in humans and animal models. The aim of this study was to examine the impact of diabetes on mesenchymal stem cells (MSCs) during fracture repair.

METHODS

Fracture of the long bones was induced in a streptozotocin-induced type 1 diabetic mouse model with or without insulin or a specific TNFα inhibitor, pegsunercept. MSCs were detected with cluster designation-271 (also known as p75 neurotrophin receptor) or stem cell antigen-1 (Sca-1) antibodies in areas of new endochondral bone formation in the calluses. MSC apoptosis was measured by TUNEL assay and proliferation was measured by Ki67 antibody. In vitro apoptosis and proliferation were examined in C3H10T1/2 and human-bone-marrow-derived MSCs following transfection with FOXO1 small interfering (si)RNA.

RESULTS

Diabetes significantly increased TNFα levels and reduced MSC numbers in new bone area. MSC numbers were restored to normal levels with insulin or pegsunercept treatment. Inhibition of TNFα significantly reduced MSC loss by increasing MSC proliferation and decreasing MSC apoptosis in diabetic animals, but had no effect on MSCs in normoglycaemic animals. In vitro experiments established that TNFα alone was sufficient to induce apoptosis and inhibit proliferation of MSCs. Furthermore, silencing forkhead box protein O1 (FOXO1) prevented TNFα-induced MSC apoptosis and reduced proliferation by regulating apoptotic and cell cycle genes.

CONCLUSIONS/INTERPRETATION

Diabetes-enhanced TNFα significantly reduced MSC numbers in new bone areas during fracture healing. Mechanistically, diabetes-enhanced TNFα reduced MSC proliferation and increased MSC apoptosis. Reducing the activity of TNFα in vivo may help to preserve endogenous MSCs and maximise regenerative potential in diabetic patients.

Bioburden after Staphylococcus aureus inoculation in type 1 diabetic rats undergoing internal fixation

SUMMARY

Fracture stabilization in the diabetic patient is associated with higher complication rates, particularly infection and impaired wound healing, which can lead to major tissue damage, osteomyelitis, and higher amputation rates. With an increasing prevalence of diabetes and an aging population, the risks of infection of internal fixation devices are expected to grow. Although numerous retrospective clinical studies have identified a relationship between diabetes and infection, currently there are few animal models that have been used to investigate postoperative surgical-site infections associated with internal fixator implantation and diabetes. The authors therefore refined the protocol for inducing hyperglycemia and compared the bacterial burden in controls to pharmacologically induced type 1 diabetic rats after undergoing internal fracture plate fixation and Staphylococcus aureus surgical-site inoculation. Using an initial series of streptozotocin doses, followed by optional additional doses to reach a target blood glucose range of 300 to 600 mg/dl, the authors reliably induced diabetes in 100 percent of the rats (n = 16), in which a narrow hyperglycemic range was maintained 14 days after onset of diabetes (mean ± SEM, 466 ± 16 mg/dl; coefficient of variation, 0.15). With respect to their primary endpoint, the authors quantified a significantly higher infectious burden in inoculated diabetic animals (median, 3.2 × 10 colony-forming units/mg dry tissue) compared with inoculated nondiabetic animals (7.2 × 10 colony-forming units/mg dry tissue). These data support the authors' hypothesis that uncontrolled diabetes adversely affects the immune system's ability to clear Staphylococcus aureus associated with internal hardware.

High glucose inhibits receptor activator of nuclear factor‑κB ligand-induced osteoclast differentiation via downregulation of v‑ATPase V0 subunit d2 and dendritic cell‑specific transmembrane protein

The balance between bone formation and resorption is compromised in diabetes, which may contribute to the high risk of fractures in diabetic patients. However, the mechanism by which high glucose affects bone turnover remains to be elucidated. The present study demonstrated that high glucose inhibited receptor activator of nuclear factor‑κB ligand (RANKL)‑induced osteoclastogenesis. In order to examine the mechanism involved in the inhibition of osteoclastogenesis, the present study examined several key molecules involved in osteoclast differentiation, including v‑ATPase V0 subunit d2 (Atp6V0d2), dendritic cell‑specific transmembrane protein (DC-STAMP), c‑fos and nuclear factor of activated T cells c1 (NFATc1). The expression levels of Atp6V0d2 and DC‑STAMP are regulated by NFATc1 and c‑fos, and are required for osteoclast fusion, which is important for osteoclast maturation. To the best of our knowledge, the present study demonstrated for the first time that high glucose decreased the gene expression of ATP6v0d2 and DC‑STAMP in RAW264.7 cells mediated by RANKL. Therefore, the suppression of pre‑osteoclast or osteoclast fusion may be essential for the inhibition of osteoclast differentiation.

Delayed fracture healing and increased callus adiposity in a C57BL/6J murine model of obesity-associated type 2 diabetes mellitus

Introduction

Impaired healing and non-union of skeletal fractures is a major public health problem, with morbidity exacerbated in patients with diabetes mellitus (DM). DM is prevalent worldwide and affects approximately 25.8 million US adults, with >90% having obesity-related type 2 DM (T2DM). While fracture healing in type 1 DM (T1DM) has been studied using animal models, an investigation into delayed healing in an animal model of T2DM has not yet been performed.

Methods

Male C57BL/6J mice at 5 weeks of age were placed on either a control lean diet or an experimental high-fat diet (HFD) for 12 weeks. A mid-diaphyseal open tibia fracture was induced at 17 weeks of age and a spinal needle was used for intra-medullary fixation. Mice were sacrificed at days 7, 10, 14, 21, 28, and 35 for micro-computed tomography (μCT), histology-based histomorphometry and molecular analyses, and biomechanical testing.

Results

HFD-fed mice displayed increased body weight and impaired glucose tolerance, both characteristic of T2DM. Compared to control mice, HFD-fed mice with tibia fractures showed significantly (p<0.001) decreased woven bone at day 28 by histomorphometry and significantly (p<0.01) decreased callus bone volume at day 21 by μCT. Interestingly, fracture calluses contained markedly increased adiposity in HFD-fed mice at days 21, 28, and 35. HFD-fed mice also showed increased PPARγ immunohistochemical staining at day 14. Finally, calluses from HFD-fed mice at day 35 showed significantly (p<0.01) reduced torsional rigidity compared to controls.

Discussion

Our murine model of T2DM demonstrated delayed fracture healing and weakened biomechanical properties, and was distinctly characterized by increased callus adiposity. This suggests altered mesenchymal stem cell fate determination with a shift to the adipocyte lineage at the expense of the osteoblast lineage. The up-regulation of PPARγ in fracture calluses of HFD-fed mice is likely involved in the proposed fate switching.

Insulin resistance and bone strength: findings from the study of midlife in the United States

Although several studies have noted increased fracture risk in individuals with type 2 diabetes mellitus (T2DM), the pathophysiologic mechanisms underlying this association are not known. We hypothesize that insulin resistance (the key pathology in T2DM) negatively influences bone remodeling and leads to reduced bone strength. Data for this study came from 717 participants in the Biomarker Project of the Midlife in the United States Study (MIDUS II). The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from fasting morning blood glucose and insulin levels. Projected 2D (areal) bone mineral density (BMD) was measured in the lumbar spine and left hip using dual-energy X-ray absorptiometry (DXA). Femoral neck axis length and width were measured from the hip DXA scans, and combined with BMD and body weight and height to create composite indices of femoral neck strength relative to load in three different failure modes: compression, bending, and impact. We used multiple linear regressions to examine the relationship between HOMA-IR and bone strength, adjusted for age, gender, race/ethnicity, menopausal transition stage (in women), and study site. Greater HOMA-IR was associated with lower values of all three composite indices of femoral neck strength relative to load, but was not associated with BMD in the femoral neck. Every doubling of HOMA-IR was associated with a 0.34 to 0.40 SD decrement in the strength indices (p<0.001). On their own, higher levels of fasting insulin (but not of glucose) were independently associated with lower bone strength. Our study confirms that greater insulin resistance is related to lower femoral neck strength relative to load. Further, we note that hyperinsulinemia, rather than hyperglycemia, underlies this relationship. Although cross-sectional associations do not prove causality, our findings do suggest that insulin resistance and in particular, hyperinsulinemia, may negatively affect bone strength relative to load.

Trabecular bone mineral density and bone geometry of the distal radius at completion of pubertal growth in childhood type 1 diabetes

AIM

To identify disease-related risk factors for an altered bone mineral density (BMD) and geometry at young adulthood in patients with diabetes mellitus type 1 (DM1).

METHODS

Fifty-six DM1 patients (23 females, 33 males) with prepubertal onset of diabetes were studied after completion of skeletal growth. Bone parameters at the distal radius were investigated by peripheral quantitative computed tomography. Disease-related parameters, in particular average HbA1c during the 2 years around peak height velocity, were analyzed. Forty-seven healthy controls (32 females, 15 males) were studied.

RESULTS

Trabecular BMD was similar between DM1 patients and controls. The mean (±SD) cross-sectional bone area (CSA) was smaller in DM1 patients compared to controls (282.5 ± 45.4 vs. 326.7 ± 52.2 mm(2), p = 0.002 and males 391.0 ± 61.3 vs. 423.4 ± 81.9 mm(2), p = 0.1). In female DM1 patients, the CSA z-score correlated negatively with the body mass index z-score (r = -0.52, p = 0.01) and positively with the height z-score (r = 0.49, p = 0.02).

CONCLUSIONS

DM1 patients are at risk for smaller bone sizes at the distal radius at the end of pubertal growth, especially females with increased adiposity. Diabetes-specific parameters seem to have a low impact on forearm volumetric apparent mineral density.

Difficult leg wounds successfully closed with decortication, bioresorbable ECM and NPWT

Complications of a missed compartment syndrome are severe. This case demonstrates the difficulty in dealing with such complications, including the difficult situation of being faced with limb salvage when amputation is the best option. Through a short case description and several images, it is demonstrated how even the most difficult wounds in cases like this can be dealt with and achieve a non-painful limb salvage. In particular, an extreme technique of decorticating the bone and applying bioresorbable extracellular matrix with negative pressure wound therapy was applied in order to achieve final wound closure and pain relief. This case demonstrates integration of multiple modalities for complex wound closure.

Position statement: hypoglycemia management in patients with diabetes mellitus. Diabetes Mellitus Working Group of the Spanish Society of Endocrinology and Nutrition

OBJECTIVE

To provide practical recommendations for evaluation and management of hypoglycemia in patients with diabetes mellitus.

PARTICIPANTS

Members of the Diabetes Mellitus Working Group of the Spanish Society of Endocrinology and Nutrition.

METHODS

Recommendations were formulated according to the Grading of Recommendations, Assessment, Development, and Evaluation system to describe both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (PubMed). Papers in English and Spanish with publication date before 15 February 2013 were included. For recommendations about drugs only those approved by the European Medicines Agency were included. After formulation of recommendations, they were discussed by the Working Group.

CONCLUSIONS

The document provides evidence-based practical recommendations for evaluation and management of hypoglycemia in patients with diabetes mellitus.

Dietary B vitamin intake and risk of hip fracture: the Singapore Chinese Health Study

This prospective cohort study that comprehensively examined effects of different B vitamins in an Asian population showed an inverse relationship between dietary intake of pyridoxine and hip fracture risk in elderly women. These findings suggest that maintaining sufficient pyridoxine intake may be beneficial in preserving bone health in postmenopausal women.

INTRODUCTION

B vitamins have recently been investigated for their possible roles in maintaining bone health. Incidence of osteoporotic hip fracture has been rising in Asia, but epidemiological data on dietary B vitamins and risk of osteoporotic fractures are sparse. We aimed to examine the association between dietary intakes of B vitamins (thiamin, riboflavin, niacin, pyridoxine, folate, and cobalamin) and hip fracture risk among elderly Chinese in Singapore.

METHODS

The current study was conducted in the Singapore Chinese Health Study, which is a population-based cohort prospective study that enrolled a total of 63,257 men and women aged 45-74 years between 1993 and 1998. Dietary intakes of B vitamins were derived from a validated food frequency questionnaire and the Singapore Food Composition Database.

RESULTS

After a mean follow-up period of 13.8 years, 1,630 hip fracture incident cases were identified. A statistically significant inverse relationship between dietary pyridoxine intake and hip fracture risk was observed among women (p for trend = 0.002) but not among men. Compared to women in the lowest quartile intake (0.37-0.61 mg/1,000 kcal/day), women in the highest quartile intake (0.78-1.76 mg/1,000 kcal/day) had a 22 % reduction in hip fracture risk (hazard ratio 0.78, 95 % confidence interval 0.66-0.93). Dietary intakes of the other B vitamins of interest were not related to hip fracture risk.

CONCLUSIONS

Our findings suggest that maintaining adequate intake of pyridoxine may prevent osteoporotic fractures among elderly women.

Diabetes and risk of fracture-related hospitalization: the Atherosclerosis Risk in Communities Study

OBJECTIVE

To examine the association between diabetes, glycemic control, and risk of fracture-related hospitalization in the Atherosclerosis Risk in Communities (ARIC) Study.

RESEARCH DESIGN AND METHODS

Fracture-related hospitalization was defined using International Classification of Diseases, 9th revision, codes (733.1-733.19, 733.93-733.98, or 800-829). We calculated the incidence rate of fracture-related hospitalization by age and used Cox proportional hazards models to investigate the association of diabetes with risk of fracture after adjustment for demographic, lifestyle, and behavioral risk factors.

RESULTS

There were 1,078 incident fracture-related hospitalizations among 15,140 participants during a median of 20 years of follow-up. The overall incidence rate was 4.0 per 1,000 person-years (95% confidence interval [CI], 3.8-4.3). Diagnosed diabetes was significantly and independently associated with an increased risk of fracture (adjusted hazard ratio [HR], 1.74; 95% CI, 1.42-2.14). There also was a significantly increased risk of fracture among persons with diagnosed diabetes who were treated with insulin (HR, 1.87; 95% CI, 1.15-3.05) and among persons with diagnosed diabetes with hemoglobin A1c (HbA1c) ≥8% (1.63; 1.09-2.44) compared with those with HbA1c <8%. Undiagnosed diabetes was not significantly associated with risk of fracture (HR, 1.12; 95% CI, 0.82-1.53).

CONCLUSIONS

This study supports recommendations from the American Diabetes Association for assessment of fracture risk and implementation of prevention strategies in persons with type 2 diabetes, particularly those persons with poor glucose control.

Moderate excess of pyruvate augments osteoclastogenesis

Cell differentiation leads to adaptive changes in energy metabolism. Conversely, hyperglycemia induces malfunction of many body systems, including bone, suggesting that energy metabolism reciprocally affects cell differentiation. We investigated how the differentiation of bone-resorbing osteoclasts, large polykaryons formed through fusion and growth of cells of monocytic origin, is affected by excess of energy substrate pyruvate and how energy metabolism changes during osteoclast differentiation. Surprisingly, small increases in pyruvate (1–2 mM above basal levels) augmented osteoclastogenesis in vitro and in vivo, while larger increases were not effective in vitro. Osteoclast differentiation increased cell mitochondrial activity and ATP levels, which were further augmented in energy-rich conditions. Conversely, the inhibition of respiration significantly reduced osteoclast number and size. AMP-activated protein kinase (AMPK) acts as a metabolic sensor, which is inhibited in energy-rich conditions. We found that osteoclast differentiation was associated with an increase in AMPK levels and a change in AMPK isoform composition. Increased osteoclast size induced by pyruvate (1 mM above basal levels) was prevented in the presence of AMPK activator 5-amino-4-imidazole carboxamide ribonucleotide (AICAR). In keeping, inhibition of AMPK using dorsomorphin or siRNA to AMPKγ increased osteoclast size in control cultures to the level observed in the presence of pyruvate. Thus, we have found that a moderate excess of pyruvate enhances osteoclastogenesis, and that AMPK acts to tailor osteoclastogenesis to a cell's bioenergetics capacity.