Bone Quality and Fracture-Healing in Type-1 and Type-2 Diabetes Mellitus

The Hawkins Sign of the Talus: The Impact of Patient Factors on Prediction Accuracy

BACKGROUND

Osteonecrosis is a complication of talar neck fractures associated with chronic pain and poor functional outcomes. The Hawkins sign, the radiographic presence of subchondral lucency seen in the talar dome 6 to 8 weeks after trauma, is a strong predictor of preserved talar vascularity. This study sought to assess the accuracy of the Hawkins sign in a contemporary cohort and assess factors associated with inaccuracy.

METHODS

A retrospective review of talar neck fractures at a level-I trauma center from 2008 to 2016 was conducted. Both the Hawkins sign and osteonecrosis were evaluated on radiographs. The Hawkins sign was determined on the basis of radiographs taken approximately 6 to 8 weeks after injury, whereas osteonecrosis was determined based on radiographs taken throughout follow-up. The Hawkins sign accuracy was assessed using proportions with 95% confidence intervals (CIs), and associations were examined with Fisher exact testing.

RESULTS

In total, 105 talar neck fractures were identified. The Hawkins sign was observed in 21 tali, 3 (14% [95% CI, 3% to 36%]) of which later developed osteonecrosis. In the remaining 84 tali without a Hawkins sign, 32 (38% [95% CI, 28% to 49%]) developed osteonecrosis. Of the 3 tali that developed osteonecrosis following observation of the Hawkins sign, all were in patients who smoked.

CONCLUSIONS

A positive Hawkins sign may not be a reliable predictor of preserved talar vascularity in all patients. We identified 3 patients with a positive Hawkins sign who developed osteonecrosis, all of whom were smokers. Factors impairing the restoration of microvascular blood supply to the talus may lead to osteonecrosis despite the presence of preserved macrovascular blood flow and an observed Hawkins sign. Further research is needed to understand the factors limiting Hawkins sign accuracy.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Diabetes-related Screw Loosening: The Distinction of Surgical Sites and the Relationship among Diabetes, Implant Stabilization and Clinical Outcomes

OBJECTIVES

Diabetes mellitus (DM) is correlated with poor clinical outcomes in spinal surgery. However, the effect of it on screw stabilization has not been investigated. The aim of this study was to evaluate the screw loosening rate and postoperative outcomes in diabetic patients and to identify potential risk factors associated with loosening.

METHODS

This was a retrospective study. Two hundred and forty-three patients who received cervical or lumbar internal fixation between 2015 and 2019 were enrolled. Screw loosening was assessed on radiography, and clinical outcomes were evaluated by the improvement of visual analogue scale (VAS), Oswestry disability index (ODI) or Japanese Orthopaedic Association (JOA) scores. The relationship of DM, screw loosening and clinical outcomes were analyzed with chi-square tests and regression analyses.

RESULTS

One hundred and twenty-two patients (50.2%) with diabetes were included in this study. Diabetes led to the increase of the rate of screw loosening in the lumbar spine, while the loosening rate did not vary significantly in the cervical spine. The occurrence of screw loosening in the lumbar spine was more likely to be associated with clinical outcomes for motor performance including walking and sitting. However, no significant effect on JOA and VAS scores in the cervical spine of screw loosening was found. Moreover, the history of DM affected the outcomes of the patients who underwent spinal surgery.

CONCLUSION

DM had an adverse effect on screw stabilization. The impaired improvement of clinical outcomes in diabetics after spinal surgery was related to screw loosening. In addition to the direct effects on operative wounds and neural function, the impact on the screws due to DM was also worth noting.

Myosin heavy chain 2 (MYH2) expression in hypertrophic chondrocytes of soft callus provokes endochondral bone formation in fracture

AIMS

Muscle-bone interactions during fracture healing are rarely known. Here we investigated the presence and significance of myosin heavy chain 2 (MYH2), a component of myosin derived from muscles, in fracture healing.

MAIN METHODS

We collected five hematoma and seven soft callus tissues from patients with distal radius fractures patients, randomly selected three of them, and performed a liquid chromatography-mass spectrometry (LC-MS) proteomics analysis. Proteomic results were validated by histological observation, immunohistochemistry, and immunofluorescence for MYH2 expression. These findings were further confirmed in a murine femoral fracture model in vivo and investigated using various methods in vitro.

KEY FINDINGS

The LC-MS proteomics analysis showed that MYH proteins were enriched in human soft calluses compared to hematoma. Notably, MYH2 protein is upregulated as high rank in each soft callus. The histological examination showed that MYH2 expression was elevated in hypertrophic chondrocytes within the human soft callus. Consistent with human data, Myh2 were significantly co-localized with Sox9 in hypertrophic chondrocytes of murine femoral fracture, in comparison to pre-hypertrophic and proliferating chondrocytes. Soluble MYH2 protein treatment increased MMP13 and RUNX2 expression in chondrocytes. In soluble MYH2 treatment, proliferation of chondrocytes was not altered, but the osteogenic and chondrogenic features of chondrocytes increased and decreased during differentiation, respectively.

SIGNIFICANCE

These findings indicate the potential of soluble MYH2 protein as a promising therapeutic strategy for promoting endochondral bone formation in chondrocytes following fracture.

Parathyroid hormone therapy improves MRSA-infected fracture healing in a murine diabetic model

Introduction

Diabetes mellitus (DM) impairs fracture healing and is associated with susceptibility to infection, which further inhibits fracture healing. While intermittent parathyroid hormone (1-34) (iPTH) effectively improves fracture healing, it is unknown whether infection-associated impaired fracture healing can be rescued with PTH (teriparatide).

Methods

A chronic diet-induced type 2 diabetic mouse model was used to yield mice with decreased glucose tolerance and increased blood glucose levels compared to lean-fed controls. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated in a surgical tibia fracture model to simulate infected fracture, after which mice were treated with a combination of antibiotics and adjunctive teriparatide treatment. Fracture healing was assessed by Radiographic Union Scale in Tibial Fractures (RUST), micro-computed tomography (μCT), biomechanical testing, and histology.

Results

RUST score was significantly poorer in diabetic mice compared to their lean nondiabetic counterparts. There were concomitant reductions in micro-computed tomography (μCT) parameters of callus architecture including bone volume/total volume, trabecular thickness, and total mineral density in type 2 diabetes mellitus (T2DM) mice. Biomechanicaltesting of fractured femora demonstrated diminished torsional rigidity, stiffness, and toughness to max torque. Adjuvant teriparatide treatment with systemic antibiotic therapy improved numerous parameters of bone microarchitecture bone volume, increased connectivity density, and increased trabecular number in both the lean and T2DM group. Despite the observation that poor fracture healing in T2DM mice was further impaired by MRSA infection, adjuvant iPTH treatment significantly improved fracture healing compared to antibiotic treatment alone in infected T2DM fractures.

Discussion

Our results suggest that teriparatide may constitute a viable adjuvant therapeutic agent to improve bony union and bone microarchitecture to prevent the development of septic nonunion under diabetic conditions.

Hydrogel Drug Delivery Systems for Bone Regeneration

With the in-depth understanding of bone regeneration mechanisms and the development of bone tissue engineering, a variety of scaffold carrier materials with desirable physicochemical properties and biological functions have recently emerged in the field of bone regeneration. Hydrogels are being increasingly used in the field of bone regeneration and tissue engineering because of their biocompatibility, unique swelling properties, and relative ease of fabrication. Hydrogel drug delivery systems comprise cells, cytokines, an extracellular matrix, and small molecule nucleotides, which have different properties depending on their chemical or physical cross-linking. Additionally, hydrogels can be designed for different types of drug delivery for specific applications. In this paper, we summarize recent research in the field of bone regeneration using hydrogels as delivery carriers, detail the application of hydrogels in bone defect diseases and their mechanisms, and discuss future research directions of hydrogel drug delivery systems in bone tissue engineering.

Exosomes Derived from Adipose Stem Cells Enhance Bone Fracture Healing via the Activation of the Wnt3a/β-Catenin Signaling Pathway in Rats with Type 2 Diabetes Mellitus

Nonunion and delayed union are common complications of diabetes mellitus that pose a serious health threat to people. There are many approaches that have been used to improve bone fracture healing. Recently, exosomes have been regarded as promising medical biomaterials for improving fracture healing. However, whether exosomes derived from adipose stem cells can promote bone fracture healing in diabetes mellitus remains unclear. In this study, adipose stem cells (ASCs) and exosomes derived from adipose stem cells (ASCs-exos) are isolated and identified. Additionally, we evaluate the in vitro and in vivo effects of ASCs-exos on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and bone repair and the regeneration in a rat model of nonunion via Western blotting, immunofluorescence assay, ALP staining, alizarin red staining, radiographic examination and histological analysis. Compared with controls, ASCs-exos promoted BMSC osteogenic differentiation. Additionally, the results of Western blotting, radiographic examination and histological analysis show that ASCs-exos improve the ability for fracture repair in the rat model of nonunion bone fracture healing. Moreover, our results further proved that ASCs-exos play a role in activating the Wnt3a/β-catenin signaling pathway, which facilitates the osteogenic differentiation of BMSCs. All these results show that ASCs-exos enhance the osteogenic potential of BMSCs by activating the Wnt/β-catenin signaling pathway, and also facilitate the ability for bone repair and regeneration in vivo, which provides a novel direction for fracture nonunion in diabetes mellitus treatment.

Fracture Healing in the Setting of Endocrine Diseases, Aging, and Cellular Senescence

More than 2.1 million age-related fractures occur in the United States annually, resulting in an immense socioeconomic burden. Importantly, the age-related deterioration of bone structure is associated with impaired bone healing. Fracture healing is a dynamic process which can be divided into four stages. While the initial hematoma generates an inflammatory environment in which mesenchymal stem cells and macrophages orchestrate the framework for repair, angiogenesis and cartilage formation mark the second healing period. In the central region, endochondral ossification favors soft callus development while next to the fractured bony ends, intramembranous ossification directly forms woven bone. The third stage is characterized by removal and calcification of the endochondral cartilage. Finally, the chronic remodeling phase concludes the healing process. Impaired fracture healing due to aging is related to detrimental changes at the cellular level. Macrophages, osteocytes, and chondrocytes express markers of senescence, leading to reduced self-renewal and proliferative capacity. A prolonged phase of "inflammaging" results in an extended remodeling phase, characterized by a senescent microenvironment and deteriorating healing capacity. Although there is evidence that in the setting of injury, at least in some tissues, senescent cells may play a beneficial role in facilitating tissue repair, recent data demonstrate that clearing senescent cells enhances fracture repair. In this review, we summarize the physiological as well as pathological processes during fracture healing in endocrine disease and aging in order to establish a broad understanding of the biomechanical as well as molecular mechanisms involved in bone repair.

Dysfunction of macrophages leads to diabetic bone regeneration deficiency

Insufficient bone matrix formation caused by diabetic chronic inflammation can result in bone nonunion, which is perceived as a worldwide epidemic, with a substantial socioeconomic and public health burden. Macrophages in microenvironment orchestrate the inflammation and launch the process of bone remodeling and repair, but aberrant activation of macrophages can drive drastic inflammatory responses during diabetic bone regeneration. In diabetes mellitus, the proliferation of resident macrophages in bone microenvironment is limited, while enhanced myeloid differentiation of hematopoietic stem cells (HSCs) leads to increased and constant monocyte recruitment and thus macrophages shift toward the classic pro-inflammatory phenotype, which leads to the deficiency of bone regeneration. In this review, we systematically summarized the anomalous origin of macrophages under diabetic conditions. Moreover, we evaluated the deficit of pro-regeneration macrophages in the diabetic inflammatory microenvironment. Finally, we further discussed the latest developments on strategies based on targeting macrophages to promote diabetic bone regeneration. Briefly, this review aimed to provide a basis for modulating the biological functions of macrophages to accelerate bone regeneration and rescue diabetic fracture healing in the future.

An engineered dual function peptide to repair fractured bones

Targeted drug delivery, often referred to as "smart" drug delivery, is a process whereby a therapeutic drug is delivered to specific parts of the body in a manner that increases its concentration at the desired sites relative to others. This approach is poised to revolutionize medicine as exemplified by the recent FDA approval of Cytalux (FDA approves pioneering drug for ovarian cancer surgery - Purdue University News) which is a folate-receptor targeted intraoperative near infrared (NIR) imaging agent that was developed in our laboratories. Fracture-associated morbidities and mortality affect a significant portion of world population. United states, Canada and Europe alone spent $48 billion in treating osteoporosis related fractures although this number doesn't count the economic burden due to loss in productivity. It is estimated that by 2050 ca 21 million hip fractures would occur globally which will be leading cause of premature death and disability. Despite the need for improvement in the treatment for fracture repair, methods for treating fractures have changed little in recent decades. Systemic delivery of fracture-homing bone anabolics holds great promise as a therapeutic strategy in this regard. Here we report the design of a fracture-targeted peptide comprised of a payload that binds and activates the parathyroid hormone receptor (PTHR1) and is linked to a targeting ligand comprised of 20 D-glutamic acids (D-Glu20) that directs accumulation of the payload specifically at fracture sites. This targeted delivery results in reduction of fracture healing times to <1/2 while creating repaired bones that are >2-fold stronger than saline-treated controls in mice. Moreover, this hydroxyapatite-targeted peptide can be administered without detectable toxicity to healthy tissues or modification of healthy bones in dogs. Additionally, since similar results are obtained upon treatment of osteoporotic and diabetic fractures in mice, and pain resolution is simultaneously accelerated by this approach, we conclude that this fracture-targeted anabolic peptide displays significant potential to revolutionize the treatment of bone fractures.

Diabetes and Impaired Fracture Healing: A Narrative Review of Recent Literature

PURPOSE OF THE REVIEW

Diabetes mellitus is a chronic metabolic disorder commonly encountered in orthopedic patients. Both type 1 and type 2 diabetes mellitus increase fracture risk and impair fracture healing. This review examines complex etiology of impaired fracture healing in diabetes.

RECENT FINDINGS

Recent findings point to several mechanisms leading to orthopedic complications in diabetes. Hyperglycemia and chronic inflammation lead to increased formation of advanced glycation end products and generation of reactive oxygen species, which in turn contribute to the disruption in osteoblast and osteoclast balance leading to decreased bone formation and heightening the risk of nonunion or delayed union as well as impaired fracture healing. The mechanisms attributing to this imbalance is secondary to an increase in pro-inflammatory mediators leading to premature resorption of callus cartilage and impaired bone formation due to compromised osteoblast differentiation and their apoptosis. Other mechanisms include disruption in the bone's microenvironment supporting different stages of healing process including hematoma and callus formation, and their resolution during bone remodeling phase. Complications of diabetes including peripheral neuropathy and peripheral vascular disease also contribute to the impairment of fracture healing. Certain diabetic drugs may have adverse effects on fracture healing. The pathophysiology of impaired fracture healing in diabetic patients is complex. This review provides an update of the most recent findings on how key mediators of bone healing are affected in diabetes.

Intertrochanteric Fracture Surgery Patients with Diabetes Mellitus are Prone to Suffer Perioperative Neurological and Endocrine/Metabolic Complications: A Propensity-Score Matched Analysis

Background

In older adults, the recovery after hip fracture surgery is not always to be well expected due to high risks of adverse outcomes including perioperative complications and mortality. We aimed to evaluate the intertrochanteric fracture (IF) patients with diabetes mellitus (DM) and receiving surgical fixation with intramedullary nail on the perioperative complications, total hospital costs (THC), length of hospital stay (LOS), and mortality.

Methods

In this retrospective cohort study, among 487 consecutive intertrochanteric fracture patients with age over 65 years and treated surgically by using intramedullary nail between Jan. 2015 and Mar. 2020, 353 patients were included, including 81 with DM and 272 without DM. After using propensity-score matched (PSM) analysis, 80 patients remained in each group. The perioperative complications, 30-day, 90-day, 1-year, and 2-year survival rates, THC, and LOS were observed and compared between two groups. Overall survival was compared by Kaplan–Meier method.

Results

No significant between-group differences were found in 30-day, 90-day, 1-year, and 2-year mortality rates, THC, LOS, and other perioperative complications after PSM and McNemar’s tests (all p>0.05), except for neurological complications (p<0.004) and endocrine/metabolic complications (p<0.001). At a mean follow-up time of 36.2 months, there were no statistically significant differences between the groups based on the Kaplan–Meier survival curve (p=0.171, log-rank).

Conclusion

IF surgery patients with DM are more prone to suffer perioperative neurological and endocrine/metabolic complications and they should be managed individually while being aware of these risks henceforth. Further high evidence clinical trials are needed to expand in DM patients with IF.

High glucose-induced inhibition of osteoblast like MC3T3-E1 differentiation promotes mitochondrial perturbations

Diabetes mellitus is a metabolic disorder that causes health concerns worldwide. Patients with diabetes exhibit multisystemic symptoms, including loss of bone quality over time. The progressive deterioration of bone promotes failure to withstand damage and increases the risk of fractures. Much of the molecular and metabolic mechanism(s) in diabetic bone remains unclear. In vitro studies suggest that hyperglycemia inhibits mineralization, affecting bone formation and function. In this study, inhibition of osteoblast differentiation was induced using hyperglycemia to assess whether high glucose promotes mitochondrial impairment along with altered bone matrix formation. It was hypothesized that bone energy metabolism would be altered in these cells as calcium deposition, a key phase for bone function, is suppressed. Early passages of osteoblast like MC3T3-E1 cells were differentiated under normal and high glucose conditions. To investigate osteoblast differentiation, we quantified calcium accumulation by alizarin red staining and analyzed immunoblots of key proteins. To assess mitochondrial function, we quantified mitochondrial DNA (mtDNA), detected expression and function of key proteins from the Tricarboxylic (TCA) cycle, measured mitochondrial respiration, and fuel oxidation of alternative nutrients. Results confirmed previous work showing that mineralization was inhibited and AKT expression was reduced in high glucose-treated bone cells. Unexpectedly, high glucose-treated osteoblast cells utilize both mitochondrial respiration and glycolysis to maintain energy demands with partial help of fatty acid for reliance of baseline bioenergetics. These metabolic shifts suggest that hyperglycemia maintain bone metabolic needs in an early differentiated state concurrent to the inhibition in bone matrix formation.

Effect of diabetes on patient-reported outcome measures at one year after laminoplasty for cervical spondylotic myelopathy

Although patients with diabetes reportedly have more peripheral neuropathy, the impacts of diabetes on postoperative recovery in pain and patient-reported outcome measures (PROMs) after laminoplasty for cervical spondylotic myelopathy (CSM) is not well characterized. The authors aimed to elucidate the effects of diabetes on neck/arm/hand/leg/foot pain and PROMs after laminoplasty CSM. The authors retrospectively reviewed 339 patients (82 with diabetes and 257 without) who underwent laminoplasty between C3 and C7 in 11 hospitals during April 2017 –October 2019. Preoperative Numerical Rating Scale (NRS) scores in all five areas, the Short Form-12 Mental Component Summary, Euro quality of life 5-dimension, Neck Disability Index, and the Core Outcome Measures Index-Neck) were comparable between the groups. The between-group differences were also not significant in NRS scores and PROMs one year after surgery. The change score of NRS hand pain was larger in the diabetic group than the nondiabetic group. The diabetic group showed worse preoperative score but greater improvement in the Short Form-12 Physical Component Summary than the nondiabetic group, following comparable score one year after surgery. These data indicated that the preoperative presence of diabetes, at least, did not adversely affect pain or PROMs one year after laminoplasty for CSM.

Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis

The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

Dynamically Bioresponsive DNA Hydrogel Incorporated with Dual-Functional Stem Cells from Apical Papilla-Derived Exosomes Promotes Diabetic Bone Regeneration

The regeneration of bone defects in patients with diabetes mellitus (DM) is remarkably impaired by hyperglycemia and over-expressed proinflammatory cytokines, proteinases (such as matrix metalloproteinases, MMPs), etc. In view of the fact that exosomes represent a promising nanomaterial, herein, we reported the excellent capacity of stem cells from apical papilla-derived exosomes (SCAP-Exo) to facilitate angiogenesis and osteogenesis whether in normal or diabetic conditions in vitro. Then, a bioresponsive polyethylene glycol (PEG)/DNA hybrid hydrogel was developed to support a controllable release of SCAP-Exo for diabetic bone defects. This system could be triggered by the elevated pathological cue (MMP-9) in response to the dynamic diabetic microenvironment. It was further confirmed that the administration of the injectable SCAP-Exo-loaded PEG/DNA hybrid hydrogel into the mandibular bone defect of diabetic rats demonstrated a great therapeutic effect on promoting vascularized bone regeneration. In addition, the miRNA sequencing suggested that the mechanism of dual-functional SCAP-Exo might be related to highly expressed miRNA-126-5p and miRNA-150-5p. Consequently, our study provides valuable insights into the design of promising bioresponsive exosome-delivery systems to improve bone regeneration in diabetic patients.

Peri-Implant Repair Using a Modified Implant Macrogeometry in Diabetic Rats: Biomechanical and Molecular Analyses of Bone-Related Markers

DM has a high prevalence worldwide and exerts a negative influence on bone repair around dental implants. Modifications of the microgeometry of implants have been related to positive results in bone repair. This study assessed, for the first time, the influence of an implant with modified macrodesign based on the presence of a healing chamber in the pattern of peri-implant repair under diabetic conditions. Thirty Wistar rats were assigned to receive one titanium implant in each tibia (Control Implant (conventional macrogeometry) or Test Implant (modified macrogeometry)) according to the following groups: Non-DM + Control Implant; Non-DM + Test Implant; DM + Control Implant; DM + Test Implant. One month from the surgeries, the implants were removed for counter-torque, and the bone tissue surrounding the implants was stored for the mRNA quantification of bone-related markers. Implants located on DM animals presented lower counter-torque values in comparison with Non-DM ones, independently of macrodesign (p < 0.05). Besides, higher biomechanical retention levels were observed in implants with modified macrogeometry than in the controls in both Non-DM and DM groups (p < 0.05). Moreover, the modified macrogeometry upregulated OPN mRNA in comparison with the control group in Non-DM and DM rats (p < 0.05). Peri-implant bone repair may profit from the use of implants with modified macrogeometry in the presence of diabetes mellitus, as they offer higher biomechanical retention and positive modulation of important bone markers in peri-implant bone tissue.

MiR-144-5p, an exosomal miRNA from bone marrow-derived macrophage in type 2 diabetes, impairs bone fracture healing via targeting Smad1

BACKGROUND

Patients with diabetes have an increased risk of nonunion and delayed union of fractures. Macrophages have been shown as a key player in diabetic complications. However, it remains obscure how diabetic milieu affects macrophage-derived exosomes and its implications on osteogenic differentiation of BMSCs. In this study, we aim to define the impact of diabetic milieu on macrophage-derived exosomes, role of extracellular vesicles in intercellular communication with BMSCs, and subsequent effects on osteogenic differentiation and fracture repair.

RESULTS

The osteogenic potential and the ability of fracture repair of exosomes derived from diabetic bone marrow-derived macrophages (dBMDM-exos) were revealed to be lower, as compared with non-diabetic bone marrow-derived macrophages (nBMDM-exos) in vitro and in vivo. Interestingly, miR-144-5p levels were sharply elevated in dBMDM-exos and it could be transferred into BMSCs to regulate bone regeneration by targeting Smad1. In addition, the adverse effects of dBMDM-exos on the osteogenic potential and the ability of fracture repair were reversed through the suppression of miR-144-5p inhibition in vitro and vivo.

CONCLUSIONS

The results demonstrated an important role of exosomal miR-144-5p in bone regeneration, offering insight into developing new strategy for the improvement of fracture healing in patients with diabetes mellitus.

A Dual Peptide Sustained-Release System Based on Nanohydroxyapatite/Polyamide 66 Scaffold for Synergistic-Enhancing Diabetic Rats' Fracture Healing in Osteogenesis and Angiogenesis

Diabetes mellitus impairs fracture healing and function of stem cells related to bone regeneration; thus, effective bone tissue engineering therapies can intervene with those dysfunctions. Nanohydroxyapatite/polyamide 66 (n-HA/PA66) scaffold has been used in fracture healing, whereas the low bioactivity limits its further application. Herein, we developed a novel bone morphogenetic protein-2- (BMP-2) and vascular endothelial growth factor- (VEGF) derived peptides-decorated n-HA/PA66 (BVHP66) scaffold for diabetic fracture. The n-HA/PA66 scaffold was functionalized by covalent grafting of BMP-2 and VEGF peptides to construct a dual peptide sustained-release system. The structural characteristics and peptide release profiles of BVHP66 scaffold were tested by scanning electron microscopy, Fourier transform infrared spectroscopy, and fluorescence microscope. Under high glucose (HG) condition, the effect of BVHP66 scaffold on rat bone marrow mesenchymal stem cells’ (rBMSCs) adherent, proliferative, and differentiate capacities and human umbilical vein endothelial cells’ (HUVECs) proliferative and tube formation capacities was assessed. Finally, the BVHP66 scaffold was applied to fracture of diabetic rats, and its effect on osteogenesis and angiogenesis was evaluated. In vitro, the peptide loaded on the BVHP66 scaffold was in a sustained-release mode of 14 days. The BVHP66 scaffold significantly promoted rBMSCs’ and HUVECs’ proliferation and improved osteogenic differentiation of rBMSCs and tube formation of HUVECs in HG environment. In vivo, the BVHP66 scaffold enhanced osteogenesis and angiogenesis, rescuing the poor fracture healing in diabetic rats. Comparing with single peptide modification, the dual peptide-modified scaffold had a synergetic effect on bone regeneration in vivo. Overall, this study reported a novel BVHP66 scaffold with excellent biocompatibility and bioactive property and its application in diabetic fracture.

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.

The surgical management of the cavity and bone defects in enchondroma cases: A prospective randomized trial

BACKGROUND

We compared the curettage/bone grafting and the curettage/bone graft substitutes surgical techniques in their relation to functional outcomes, oncologic outcome (recurrence, malignant transformation), the rate of postsurgical complications, durations of surgery and of postsurgical immobilization for hand-localized cases of solitary and multiple enchondromas.

METHODS

The current prospective randomized trial analyzed 200 adult patients (2012-2017) with enchondroma who underwent surgical intervention. The cases were randomly divided into Group 1 (n = 100; F 56, M 44) for surgeries with curettage and autogenous bone grafting, and Group 2 (n = 100; F 55, M 45) for surgeries with curettage and bone graft substitutes. The placebo control Group 3 consisted of cases operated by curettage only (n = 56; F 31, M 25). The follow-up period was set at 30 months.

RESULTS

The duration of surgery was 51 ± 4 min in Group 1 and 27 ± 1 min in Group 2 (p = 0.008). In Group 1, the rate of recurrence was 6% against 1% in Group 2 (p = 0.005). No other statistically significant differences in postsurgical outcomes between three involved groups were noted.

CONCLUSION

In cases of enchondroma of the hand, postsurgical functional outcomes, the rate of postsurgical complications, the duration of immobilization, and the time to complete recovery are not influenced by the type of chosen grafting material. The implementation of HAp-collagen bone substitutes in granules instead of autogenous bone grafting reduces the duration of surgery. The implementation of autogenous bone grafting may increase the rate of tumor recurrence.

Diabetes Does Not Adversely Affect Neurological Recovery and Reduction of Neck Pain After Posterior Decompression Surgery for Cervical Spondylotic Myelopathy: Results From a Retrospective Multicenter Study of 675 Patients

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

The aim of this study was to identify the impact of diabetes on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Although some previous studies have reported surgical outcomes of posterior decompression for CSM in diabetic patients, their results were inconsistent.

METHODS

We included 675 patients with CSM who underwent posterior decompression. Patients were divided into diabetic (n = 140) and nondiabetic (n = 535) groups according to the diabetic criteria for glucose intolerance. Surgical outcomes as assessed by the Japanese Orthopedic Association (JOA) scores and visual analog scale (VAS) for neck pain were compared between groups. Subsequently, the functional outcomes of diabetic patients were compared between the mild (n = 131) and moderately severe (n = 9) groups. All patients were followed up for at least 1 year after surgery.

RESULTS

Compared with the nondiabetic group, the diabetic group showed lower pre- and postoperative JOA scores (P = 0.025 and P = 0.001, respectively) and a lower JOA score recovery rate (RR) (P = 0.009). However, the preoperative-to-postoperative changes in JOA scores in the diabetic and nondiabetic groups were not significantly different (P = 0.988). Pre- and postoperative VAS for neck pain and postoperative reduction of neck pain were comparable between groups (P = 0.976, P = 0.913 and P = 0.688, respectively). Although statistical analysis was not performed due to the small underpowered sample size, functional outcomes assessed by the JOA score RR (43.3 ± 37.1% vs. 45.3 ± 33.9%) and preoperative-to-postoperative changes in JOA scores (3.0 ± 2.2 vs. 2.7 ± 2.5) were similar between the mild and moderately severe diabetes groups.

CONCLUSION

CSM patients with diabetes experienced improvements in neurological function and neck pain as a result of posterior decompression to the same extent seen in patients without diabetes.Level of Evidence: 3.

Development of stabilized dual growth factor-loaded hyaluronate collagen dressing matrix

Patients with diabetes experience impaired growth factor production such as epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), and they are reportedly involved in wound healing processes. Here, we report dual growth factor-loaded hyaluronate collagen dressing (Dual-HCD) matrix, using different ratios of the concentration of stabilized growth factors—stabilized-EGF (S-EGF) and stabilized-bFGF (S-bFGF). At first, the optimal concentration ratio of S-EGF to S-bFGF in the Dual-HCD matrix is determined to be 1:2 in type I diabetic mice. This Dual-HCD matrix does not cause cytotoxicity and can be used in vivo. The wound-healing effect of this matrix is confirmed in type II diabetic mice. Dual HCD enhances angiogenesis which promotes wound healing and thus, it shows a significantly greater synergistic effect than the HCD matrix loaded with a single growth factor. Overall, we conclude that the Dual-HCD matrix represents an effective therapeutic agent for impaired diabetic wound healing.

Outcome of fragility hip fractures in elderly patients: Does diabetes mellitus and its severity matter?

AIMS

Diabetes mellitus (DM) and osteoporosis are both diseases of epidemic proportions with an increasing incidence worldwide. Fragility hip fractures (FHF) are associated with elevated morbidity, mortality, social burden and medical costs. The aim of this study was to determine whether patients with DM have worse medical and surgical outcomes following FHFs and whether the Diabetes Complications Severity Index (DCSI) can predict in-hospital complications and one-year mortality.

METHODS

A single centre retrospective cohort study including 1343 patients older than 65 years who underwent surgery for FHFs was conducted. The data collected included length of hospital stay, time-to-surgery, blood loss, complications and mortality during the first post-operative year.

RESULTS

408 patients with a DM diagnosis were compared with 935 without DM. Pre-operatively, patients with DM had lower haemoglobin levels, higher platelet counts and worse renal function. Following surgery, patients with DM were more likely to be transferred to another department or intensive care. One-year mortality was significantly higher in the DM group [23.3% vs. 17.1%, odds ratio 1.36 (CI 1.029-1.799, p = 0.03)]. Higher DCSI scores were related with elevated one-year mortality rates in the DM group. Cerebrovascular events were found to be nearly five times more prevalent in the DM group. Patients with DM were more likely to continue treatment in a rehabilitation centre and had a higher probability to be re-hospitalized in the first post-operative year (p.<0.001).

CONCLUSIONS

Our results emphasize the increased vulnerability of this patient population and the importance of specialized care during the peri-operative period of FHFs.

Bone turnover and metabolite responses to exercise in people with and without long-duration type 1 diabetes: a case-control study

INTRODUCTION

Exercise acutely alters markers of bone resorption and formation. As risk of fracture is increased in patients with type 1 diabetes, understanding if exercise-induced bone turnover is affected within this population is prudent. We assessed bone turnover responses to acute exercise in individuals with long-duration type 1 diabetes and matched controls.

RESEARCH DESIGN AND METHODS

Participants with type 1 diabetes (n=15; age: 38.7±13.3; glycosylated hemoglobin: 60.5±6.7 mmol/mol; diabetes duration: 19.3±11.4 years) and age-matched, fitness-matched, and body mass index-matched controls (n=15) completed 45 min of incline walking (60% peak oxygen uptake). Blood samples were collected at baseline and immediately, 30 min, and 60 min postexercise. Markers of bone resorption (β-C-terminal cross-linked telopeptide of type 1 collagen, β-CTx) and formation (procollagen type-1 amino-terminal propeptide, P1NP), parathyroid hormone (PTH), phosphate, and calcium (albumin-adjusted and ionized) were measured. Data (mean±SD) were analyzed by a mixed-model analysis of variance.

RESULTS

Baseline concentrations of P1NP and β-CTx were comparable between participants with type 1 diabetes and controls. P1NP did not change with exercise (p=0.20) but β-CTx decreased (p<0.001) in both groups, but less so in participants with type 1 diabetes compared with controls (-9.2±3.7%; p=0.02). PTH and phosphate increased immediately postexercise in both groups; only PTH was raised at 30 min postexercise (p<0.001), with no between-group differences (p>0.39). Participants with type 1 diabetes had reduced albumin and ionized calcium at all sample points (p<0.01).

CONCLUSIONS

Following exercise, participants with type 1 diabetes displayed similar time-course changes in markers of bone formation and associated metabolites, but an attenuated suppression in bone resorption. The reduced albumin and ionized calcium may have implications for future bone health. Further investigation of the interactions between type 1 diabetes, differing modalities and intensities of exercise, and bone health is warranted.

Bone-Targeting Systems to Systemically Deliver Therapeutics to Bone Fractures for Accelerated Healing

PURPOSE OF REVIEW

Compared with the current standard of implanting bone anabolics for fracture repair, bone fracture-targeted anabolics would be more effective, less invasive, and less toxic and would allow for control over what phase of fracture healing is being affected. We therefore sought to identify the optimal bone-targeting molecule to allow for systemic administration of therapeutics to bone fractures.

RECENT FINDINGS

We found that many bone-targeting molecules exist, but most have been developed for the treatment of bone cancers, osteomyelitis, or osteoporosis. There are a few examples of bone-targeting ligands that have been developed for bone fractures that are selective for the bone fracture over the body and skeleton. Acidic oligopeptides have the ideal half-life, toxicity profile, and selectivity for a bone fracture-targeting ligand and are the most developed and promising of these bone fracture-targeting ligands. However, many other promising ligands have been developed that could be used for bone fractures.

Rates and Risk Factors for Failure of Surgical Repair of the Knee Extensor Mechanism

OBJECTIVES

To evaluate rates and risk factors for failed surgical repair of the knee extensor mechanism.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENTS/PARTICIPANTS

Two hundred ninety-four patients and a total of 303 extensor mechanism repairs were included. This encompassed 113 quadriceps tendon repairs (QTR), 112 fracture repairs (FR), and 68 patellar tendon repairs (PTR).

MAIN OUTCOME MEASUREMENT

Repair failure.

RESULTS

There were 6 failures (5%) in the QTR group, 21 failures (17%) in the FR group, and 2 failures (3%) in the PTR group. The difference in failure rates between the groups was significant (P = 0.001), but the rate of revision fixation or repair was not (P = 0.315). In the QTR group, a history of inflammatory arthritis was found to be significantly different between patients who had repair failure and patients who did not (P = 0.014) with a relative risk for failure of 17.8 (confidence interval 4.5-70.4). In the FR group, patient age (P = 0.001) and comorbid diabetes mellitus (P = 0.046) were found to be significantly different between patients with and without repair failure in univariate analysis, but only patient age (P = 0.005) was significant in multiple logistic regression analysis. The relative risk for FR failure was 6.6 (confidence interval 2.3-18.3) for age greater than 60. No risk factors for failure were identified in the PTR group.

CONCLUSIONS

Overall, patients with fractures were more likely experience repair failure than patients with tendon injuries, but all patients underwent similar rates of reoperation. Inflammatory arthritis in patients with QTRs and older patient age in FRs are risk factors for repair failure.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.