Teriparatide and Abaloparatide Have a Similar Effect on Bone in Mice.

Three bone anabolic pharmaceuticals are currently approved for treatment of osteoporosis, teriparatide (PTH (1-34)), the parathyroid hormone-related protein analog abaloparatide (ABL), and romosozumab. The present study compared the effect of intermittent PTH (1-34) and ABL on bone tissue directly mole-to-mole in female mice. Forty-seven C57BL/6 mice were randomly allocated to the following groups: Baseline (n = 11), Control (Ctrl) (n = 12), PTH (n = 12), and ABL (n = 12). The mice were injected s.c. with PTH (100 µg/kg), ABL (96 µg/kg), or saline (Ctrl) five days a week for three weeks. To assess the effect of PTH and ABL, the hindlimb bones were analyzed with DXA, µCT, mechanical testing, dynamic bone histomorphometry, and histological quantification of bone cells. In addition, serum calcium concentration was determined. PTH and ABL significantly increased femoral areal bone mineral density (aBMD) (borderline significant p = 0.06 for PTH), femoral mid-diaphyseal bone strength, femoral metaphyseal and epiphyseal and vertebral bone volume fraction (BV/TV), connectivity density, volumetric bone mineral density (vBMD), and bone formation rate (BFR/BS) compared to Ctrl. In addition, ABL also significantly increased mid-diaphyseal cortical thickness and bone area compared to Ctrl. Neither PTH nor ABL significantly increased bone strength at the femoral neck. In conclusion, abaloparatide and PTH have similar bone anabolic properties when compared directly mole-to-mole in mice.

Effects of triangle grass decoction on bone metabolism in rats with chronic kidney disease complicated with mineral and bone abnormalities.

ETHNOPHARMACOLOGICAL RELEVANCE: Triangle grass is a liliaceous Chlorophytum perennial herb of ChlorophytumlaxumR.Br. It is distributed mainly in Guangdong and Guangxi Provinces of China. The initial use of triangle grass was mainly to treat bone pain and swelling caused by a fall injury. Triangle grass tablets (NO. Z20070544) are also used as a preparation in our hospital because of their analgesic, anti-inflammatory, anti-snake venom and microcirculation improvement properties and other pharmacological effects (Mei et al., 2006). Triangle grass tablets have been widely used in our hospital to treat patients with bone pain from chronic kidney disease-mineral and bone disorder (CKD-MBD). However, the effects and mechanism of triangle grass on bone metabolism in chronic kidney disease complicated with mineral and bone abnormalities are unclear. AIM OF THE STUDY: The aim of the present study was to investigate the effects of a triangle grass decoction on bone metabolism in CKD-MBD rats. MATERIALS AND METHODS: CKD-MBD model rats were subjected to 5/6 nephrectomy combined with 0.5 g NaH2PO4/rat. Serum blood urea nitrogen (BUN), creatinine (Cr), phosphorus (P), calcium (Ca), and intact parathyroid hormone (iPTH) levels were measured with an automatic biochemical analyser. Bone mineral density was determined with a Viva CT 40 system. Bone morphogenetic protein 7(BMP-7),runt-related transcription factor 2 (Runx2) and Osterix protein levels were measured by Western blot analysis. Kidney, vertebra and thoracic aorta tissue samples were assessed by histopathology and immunohistochemistry (IHC). RESULTS: The degrees of membrane thickening, necrosis, swelling and cast deposition were significantly reduced in high-dose rats and Low-dose rats. Serum BUN levels were significantly reduced in the Pre-H group (P < 0.05). Hypocalcaemia and hyperphos phataemia were detected in triangle grass (P < 0.05, P < 0.05). In addition, iPTH levels were significantly increased in the Pre-H group (P < 0.05). Alkaline phosphatase (ALP)levels were significantly decreased in the Pre-H group (P < 0.05). The bone mineral density was improved in the Pre-H and Pre-L groups. BMP-7 protein levels were significantly increased in the Pre-H group (P < 0.05). The pathological changes in muscle fibres in the thoracic aorta middle membranes were significantly alleviated in rats in the Pre-H and Pre-L groups. Changes in SM22α and SMα-act in protein levels were significantly attenuated in the Pre-H group (P < 0.05, P < 0.05). Changes in Runx2 and Osterix protein levels were also significantly attenuated in the Pre-H and Pre-L groups (P < 0.05, P < 0.05). CONCLUSIONS: Triangle grass can simultaneously ameliorate vertebral bone loss and abnormal calcification in the thoracic aorta. Triangle grass has a definite effect on bone metabolism disorder in CKD-MBD rats.

Efficacy and safety of intrathecal morphine for pain control after spinal surgery: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to assess the efficacy and safety of intrathecal (IT) morphine for postoperative pain control in adults undergoing spinal surgeries. We searched the electronic databases of PubMed, Embase, and CENTRAL up to 1st January 2021 for randomized controlled trials (RCTs) or controlled clinical trials (CCTs) comparing IT morphine with placebo or other analgesics. Twelve studies were included. Eleven were RCTs and one was a CCT. Our meta-analysis indicated a statistically significant reduction of pain scores with IT morphine at 2 hours, 4 hours, 6 hours, 8 hours, 12 hours, and 24 hours; but no significant difference at 48 hours. Meta-analysis indicated a statistically significant reduction in analgesic consumption with IT morphine as compared to control. Pooled analysis indicated that IT morphine had no statistically significant effect on length of hospital stay. Our analysis indicated no statistically significant difference in the risk of nausea, vomiting, sedation, respiratory depression, headache, and urinary retention between IT morphine and control groups. The incidence of pruritis was significantly increased in the IT morphine group. The certainty of the evidence was judged to be "moderate" for pain scores at 12 hours, 24 hours, and analgesic consumption. To conclude, our review indicates that IT morphine results in significantly better pain control in the first 24 hours after spinal surgery. The risk of pruritis is significantly increased with the use of IT morphine but not for other opioid-related adverse events. Future RCTs should focus on finding the most optimal dose of IT morphine for spinal surgeries.

Off-treatment bone mineral density changes in postmenopausal women receiving anastrozole for 5 years: 7-year results from the IBIS-II prevention trial.

BACKGROUND: Anastrozole has been associated with substantial accelerated bone mineral density (BMD) loss during active treatment. METHODS: One thousand four hundred and ten women were included in a BMD substudy and stratified into three strata according to their baseline T-score at spine or femoral neck. The primary objective of this analysis was to investigate whether DXA BMD at the spine and hip changed two years after treatment cessation (between years 5 and 7) in those who did not receive risedronate. RESULTS: Five- and seven-year BMD data were available for a total of 528 women who did not receive risedronate. In women with normal BMD at baseline, an increase in BMD at the lumbar spine after anastrozole withdrawal was observed 1.25% (95% CI 0.73 to 1.77) (P = 0.0004), which was larger than in those on placebo (0.14% (-0.29 to 0.56))). At the hip, BMD remained unchanged between years 5 and 7 for those previously on anastrozole but continued to a decrease in those who had been randomised to placebo (-1.35% (-1.70 to -0.98)). CONCLUSIONS: These are the first results reporting BMD changes after stopping anastrozole in a breast cancer prevention setting. Our results show that the negative effects of anastrozole on BMD in the preventive setting are partially reversible.

Protective effect of gastrodin on peripheral neuropathy induced by anti-tumor treatment with vincristine in rat models.

Cancer is a common disease threatening human health, chemotherapy is widely used in clinical treatment of cancer, but chemotherapy-induced peripheral neuropathy (CIPN) has a relevant impact on life quality of cancer patients. Administration of gastrodin can relieve chronic pain to cancer patients with CIPN and attenuated the inflammatory response by reducing the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). However, its exact molecular mechanisms remain unclear. In this study, we established an animal model of CIPN using Walker-256 breast cancer cell and vincristine. We found that the mechanical and thermal pain threshold of rats was decreased with treatment of vincristine. Using gastrodin could restore the mechanical and thermal threshold without interfering anti-tumor effect of vincristine. Gastrodin relieved CIPN by inhibiting activation of spinal microglia through Fractalkine (CX3CL1) and its receptor CX3CR1, then inhibited P38/mitogen-activated protein kinase (MAPK) signaling pathway and reduced the expression of inflammatory factor TNF-α and interleukin-1ß (IL-1ß). Taking together, our study demonstrated that gastrodin is a potential drug for the treatment of CIPN and likely to improve cancer patient's life quality.

Early achievement of ASDAS clinical response is associated with long-term improvements in metrological outcomes in patients with ankylosing spondylitis treated with TNF-α blockers.

The aim of this study was to investigate the relationship between long-term spinal mobility improvements and early disease activity changes or achievement of clinical response criteria in patients with ankylosing spondylitis (AS) treated with tumor necrosis factor (TNF-α) blockers.This retrospective study included 112 patients with AS treated with TNF-α blockers for up to 33 months. The paired t-test was used to compare outcome measures between visits. The correlation between disease activity changes and metrological improvements was analyzed using cumulative probability plots, Spearman correlation coefficient, and canonical correlation. The difference in metrological outcomes between responders and non-responders to clinical response criteria was also examined.Metrological and disease activity outcomes improved most markedly in month 3. All disease activity outcomes and ESR from baseline to month 3 (3-month) were significantly correlated with the Bath Ankylosing Spondylitis Metrology Index (BASMI10) improvements from baseline to month 33 (33-month). The 3-month changes in ankylosing spondylitis disease activity score (ASDAS-CRP) and patient's global assessment showed a significant correlation with the 33-month changes in chest expansion. Only responders according to ASDAS major improvement at month 3 demonstrated significant 33-month improvements in both BASMI10 and chest expansion, compared to non-responders. Responders according to Assessment of Spondylo Arthritis international Society 40 at month 3 showed significant 33-month improvements in BASMI10, but not chest expansion, compared to non-responders.The degree of early changes in disease activity outcomes influenced the extent of long-term metrological improvements in AS treated with TNF-α blockers. Additionally, the achievement of ASDAS- major improvement at month 3 predicted significant metrological improvements throughout long-term TNF-α-blocker therapy.

Early changes in bone turnover and inflammatory biomarkers and clinically significant bone mineral density loss over 48 weeks among HIV-infected patients with virological failure of a standard first-line antiretroviral therapy regimen in the SECOND-LINE study.

OBJECTIVES: We assessed whether changes at week 12 in markers of bone turnover, inflammation, and immune activation were associated with clinically important (≥ 5%) bone mineral density (BMD) loss from baseline to week 48 at the proximal femur (hip) and lumbar spine in the SECOND-LINE study. METHODS: We measured concentrations of procollagen type 1 pro-peptide (P1NP), carboxyl-terminal collagen crosslinks (CTX), high-sensitivity C-reactive protein (hs-CRP), D-dimer, interleukin (IL)-6, tumor necrosis factor (TNF), neopterin, and soluble CD14 and 163 at weeks 0, 12, and 48 in 123 SECOND-LINE dual-energy X-ray absorptiometry (DXA) substudy participants. Linear regression was used to compare changes in biomarkers. Predictors of ≥ 5% BMD loss were examined using multivariable regression. RESULTS: The mean age was 38 years, the mean CD4 T-cell count was 252 cells/µL and the mean viral load was 4.2 log HIV-1 RNA copies/mL; 56% of participants were female and 47% were randomized to receive a nucleos(t)ide reverse transcriptase inhibitor [N(t)RTI]-based regimen [91% (53/58) were randomized to receive a tenofovir disoproxil fumarate (TDF)-containing regimen]. Over 48 weeks, 71% in the N(t)RTI arm experienced ≥ 5% hip BMD loss vs. 29% in the raltegravir arm (P = 0.001). Week 12 changes in P1NP and CTX were significantly greater among patients experiencing ≥ 5% hip BMD loss, patients randomized to N(t)RTI, and male patients. Predictors of ≥ 5% hip BMD loss at week 48 were P1NP increase [odds ratio (OR) 5.0; 95% confidence interval (CI) 1.1-27; P < 0.043]; N(t)RTI randomization (OR 6.7; 95% CI 2.0-27.1; P < 0.003), being African, higher baseline CD4 T cell count , and smoking. CONCLUSIONS: In a diverse cohort of viraemic HIV-infected patients, switching to second-line antiretroviral therapy (ART) was associated with clinically significant BMD loss, which was correlated with an early increase in P1NP. Measurement of P1NP may facilitate timely interventions to reduce rapid BMD loss among at-risk patients.

Erector spine plane block as postoperative rescue analgesia in thoracic surgery.

OBJECTIVE: Erector spine plane block (ESPB) is a newly defined regional anesthesia technique performed by injection of local anesthetic beneath the erector spine muscle. We tested ESPB as a regional rescue analgesia bedside technique to be performed in the thoracic surgical ward, reporting a 7-patient case series. METHODS: We report our experience in rescue analgesia after thoracic surgery. During the postoperative stay, numeric rating scale (NRS) score >3 and inability to perform physiotherapy or effective cough due to postoperative pain represented the criteria for proposing rescue analgesia with ESPB. NRS at rest and during movements was recorded; blood gas analysis and spirometry were performed to evaluate PaO2/FiO2 (P/F), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) before ESPB execution. After performing the ESPB, static and dynamic NRS, P/F, and FVC and FEV1 were recorded at 40 minutes and 80 minutes. RESULTS: NRS had a reduction at rest and in dynamic assessment. The P/F did not improve but spirometric measures improved. FVC had a relevant improvement only after 80 minutes; FEV1 was increased after 40 minutes. CONCLUSION: The use of ESPB as postoperative rescue analgesia can offer several advantages due to effective rescue analgesia and safety that makes it easy to perform in the thoracic surgical ward or in an outpatient clinic setting.

Radiation therapy combined with bone-modifying agents ameliorates local control of osteolytic bone metastases in breast cancer.

Bone-modifying agents (BMAs) are frequently used for the treatment of bone metastases. Both BMA and radiation therapy (RT) are effective; however, there are few studies that have evaluated the efficacy of the combination treatment. We evaluated the effectiveness of RT + BMA in breast cancer-induced osteolytic bone metastasis as compared to BMA alone. A total of 43 lesions in 25 patients were evaluated. The median follow-up period was 18 (range, 2-90) months. None of the lesions was treated with chemotherapy or molecular targeted drugs during the follow-up period for evaluating the local response. Patients with complete or partial response were considered as responders, while those with stable or progressive disease were considered as non-responders. The rate of response with RT + BMA was significantly higher than that with BMA alone (P = 0.001). The cumulative incidence rate of response at 6 months was 54.4% in the RT + BMA group and 27.5% in the BMA alone group. The median time to response was 4 (range, 2-11) months in the RT + BMA group and 6 (range, 4-16) months in the BMA alone group. The overall survival rate in the responder group (83.1% at 1 year) was significantly higher than that in the non-responder group (37.5% at 1 year) (P = 0.029). In conclusion, RT combined with BMA was found to be more effective than BMA alone for the treatment of osteolytic bone metastasis, which thereby improves the prognosis.

Local osteo-enhancement of osteoporotic vertebra with a triphasic bone implant material increases strength-a biomechanical study.

PURPOSE: The aim of this study was to assess the biomechanical properties of intact vertebra augmented using a local osteo-enhancement procedure to inject a triphasic calcium sulfate/calcium phosphate implant material. METHODS: Twenty-one fresh frozen human cadaver vertebra (Th11-L2) were randomized into three groups: treatment, sham, and control (n = 7 each). Treatment included vertebral body access, saline lavage to displace soft tissue and marrow elements, and injection of the implant material to fill approximately 20% of the vertebral body by volume. The sham group included all treatment steps, but without injection of the implant material. The control group consisted of untreated intact osteoporotic vertebra. Load at failure and displacement at failure for each of the three groups were measured in axial compression loading. RESULTS: The mean failure load of treated vertebra (4118 N) was significantly higher than either control (2841 N) or sham (2186 N) vertebra (p < 0.05 for: treatment vs. control, treatment vs. sham). Treated vertebra (1.11 mm) showed a significantly higher mean displacement at failure than sham vertebra (0.80 mm) (p < 0.05 for: treatment vs. sham). In the control group, the mean displacement at failure was 0.99 mm. CONCLUSIONS: This biomechanical study shows that a local osteo-enhancement procedure using a triphasic implant material significantly increases the load at failure and displacement at failure in cadaveric osteoporotic vertebra.

Pasteurized Akkermansia muciniphila protects from fat mass gain but not from bone loss.

Probiotic bacteria can protect from ovariectomy (ovx)-induced bone loss in mice. Akkermansia muciniphila is considered to have probiotic potential due to its beneficial effect on obesity and insulin resistance. The purpose of the present study was to determine if treatment with pasteurized Akkermansia muciniphila (pAkk) could prevent ovx-induced bone loss. Mice were treated with vehicle or pAkk for 4 wk, starting 3 days before ovx or sham surgery. Treatment with pAkk reduced fat mass accumulation confirming earlier findings. However, treatment with pAkk decreased trabecular and cortical bone mass in femur and vertebra of gonadal intact mice and did not protect from ovx-induced bone loss. Treatment with pAkk increased serum parathyroid hormone (PTH) levels and increased expression of the calcium transporter Trpv5 in kidney suggesting increased reabsorption of calcium in the kidneys. Serum amyloid A 3 (SAA3) can suppress bone formation and mediate the effects of PTH on bone resorption and bone loss in mice and treatment with pAkk increased serum levels of SAA3 and gene expression of Saa3 in colon. Moreover, regulatory T cells can be protective of bone and pAkk-treated mice had decreased number of regulatory T cells in mesenteric lymph nodes and bone marrow. In conclusion, treatment with pAkk protected from ovx-induced fat mass gain but not from bone loss and reduced bone mass in gonadal intact mice. Our findings with pAkk differ from some probiotics that have been shown to protect bone mass, demonstrating that not all prebiotic and probiotic factors have the same effect on bone.

Comparative study of the effects of osteoprotegerin and testosterone on bone quality in male orchidectomised rats.

Aim: The aim of this work is to compare the effects of osteoprotegerin (OPG) and testosterone on bone quality in a model of orchidectomised (ORX) rats.Methods: Three-month-old ORX or SHAM operated groups (n = 15 each group) were used. The SHAM and ORX groups received saline. There were two ORX groups, receiving OPG-Fc (10 mg/kg twice weekly) (ORX + OPG-Fc) or testosterone cypionate (1.7 mg/kg/weekly) for 8 weeks. After sacrifice, bone analysis by femoral and lumbar dual-energy X-ray absorptiometry and micro-computed tomography in femora were performed. Histological sections of vertebrae were dyed with hematoxylin-eosin or safranin. Serum osteocalcin (BGP), total alkaline phosphatase (ALP), and C-terminal telopeptide of type I collagen (CTX) were analyzed.Results: ORX resulted in femoral and vertebral bone loss and in microarchitectural deterioration. Treatment with OPG-Fc and testosterone recovered lumbar (L) and femoral (F) bone mineral densitometry bone mineral density (BMD) to SHAM levels. Femoral BMD was significantly higher after treatment with OPG-Fc than after testosterone treatment due to the presence of osteopetrotic changes in the metaphyseal region of long bones. Serum levels of ALP and CTX increased, while OPG levels were unchanged in ORX rats. Treatment with OPG-Fc decreased the levels of BGP, ALP, and CTX. Treatment with testosterone maintained biochemical markers of bone turnover at levels similar to or higher than those of ORX rats.

Drug Delivery Applications of Nanoparticles in the Spine.

Nanoparticles offer several applications in the field of medicine such as targeted drug delivery, controlled drug release, and imaging applications. The central nervous system (CNS), in particular, has remained a challenge for drug delivery. This is mainly due to barriers such as the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB), which hinder drug molecules from reaching the brain and spinal cord tissue. Although researchers have mainly focused on applying nanotechnology in the brain, there is an increase in applications of nanomaterials in the spine as well. This chapter focuses on the potential of nanomedicine for medical applications in the spine, including unique drug delivery systems and gene therapy applications, and for enhancement of medical imaging. We look at the problems and recent advances in the development of nanoparticles for spine-related applications and provide a comprehensive review on recent research work.

Chronic administration of Cl-amidine, a pan-peptidylarginine deiminase inhibitor, does not reverse bone loss in two different murine models of osteoporosis.

Recent in vitro studies have shown a role for the peptidyl-arginine deiminases (PADs) in bone resorption. However, it is unknown whether these enzymes are involved in bone loss in vivo. Thus, we evaluated the antiresorptive effect of a pan-PAD inhibitor in two murine models of osteoporosis: (a) primary osteoporosis induced by ovariectomy (OVX); and (b) secondary osteoporosis associated to Type-1 diabetes induced by streptozotocin (STZ, 50 mg/kg, i.p., five daily administrations). Five weeks after OVX and 15 weeks after injections of STZ, mice received daily administrations of Cl-amidine (3 or 10 mg/kg, i.p.) or vehicle for 30 consecutive days. At the end of the treatment, femur and vertebra were harvested for microCT analysis. Blood samples were collected for determination of antibodies against cyclic citrullinated peptides (anti-CCP) by enzyme-linked immunosorbent assay. Serum levels of anti-CCP antibodies from diabetic mice were not significantly different compared to control mice. However, a significant loss of both trabecular bone at the femoral neck and cortical bone at the femoral diaphysis was found in diabetic mice, and Cl-amidine did not reverse the diabetes-induced bone loss. Mice with OVX had significantly lower serum levels of anti-CCP compared to mice with sham surgery. OVX resulted in significant loss of both trabecular bone at the L5 vertebra and distal femoral metaphysis. Cl-amidine did not block the OVX-induced bone loss. Our results suggest that chronic treatment with Cl-amidine at the doses and period of time administered is not long enough to inhibit bone loss in two different murine models of osteoporosis.

Effect of tumor necrosis factor inhibition on spinal inflammation and spinal ankylosis in SKG mice.

To prevent spinal progression in ankylosing spondylitis, initiating TNF-inhibitor treatment as early as possible is suggested. However, the outcomes are inconsistent in previous clinical studies. Here, we investigated the effect of TNF inhibition alone on spinal progression when used during arthritis development in a murine model. We injected 8-week-old SKG mice with curdlan (curdlan group). We injected adalimumab at 3 and 9 weeks after the first curdlan injection (ADA group). The clinical scores of peripheral arthritis decreased in the ADA group at 3 weeks after first adalimumab injection. Using positron emission tomography-magnetic resonance imaging and histologic examination, spinal inflammation was observed in the curdlan group, and was significantly deceased in the ADA group. However, spinal osteoblast activities by imaging using OsteoSense 680 EX and bone metabolism-related cytokines such as receptor activator of nuclear factor-kappa B ligand, osteoprotegerin, Dickkopf-1, and sclerostin levels except IL-17A level were not different between the two groups. We conclude that treating TNF inhibitor alone reduced peripheral arthritis score and spinal inflammation in curdlan-injected SKG mice but did not decrease the spinal osteoblast activity, suggesting little effect on spinal ankylosis.

Inhibition of spinal bone formation in AS: 10 years after comparing adalimumab to OASIS.

A decade has passed since the publication on the comparison of the effect of adalimumab with data from a historic cohort on the progression of structural damage in the spine of patients with ankylosing spondylitis (AS). No effect could be observed, and currently, there is still no definite proof that TNF inhibitors (TNFi) inhibit spinal structural damage. The findings of the publication are discussed within the context of the time at the publication and new developments.

Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain

Abstract Purpose: To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP). Methods: The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity. Results: Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively). Conclusion: The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.

Injectable Catalyst-Free Poly(Propylene Fumarate) System Cross-Linked by Strain Promoted Alkyne-Azide Cycloaddition Click Chemistry for Spine Defect Filling.

A new PPF-BCN/hyPCL32-N3 injectable system that can be cross-linked by catalyst-free, strain promoted alkyne-azide cycloaddition (SPAAC) click chemistry was developed for tissue engineering applications. The system consisted of two components: PPF-BCN, poly(propylene fumarate) (PPF) functionalized with (1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN-OH), and hyPCL32-N3, a hyper-branched 32-arm poly(ε-caprolactone) (PCL) dendrimer functionalized with azide as the cross-linker core. Fast SPAAC click reaction allowed the desired gelation of the system without using any toxic initiator or catalyst. Compared to the conventional injectable formulation, e.g., poly(methyl methacrylate) (PMMA), our PPF-BCN/hyPCL32-N3 (abbreviated as PFCL-Click) injectable system showed enhanced biocompatibility and low heat generation during cross-linking. After reaction, the cross-linked PFCL-Click scaffolds supported excellent proliferation and differentiation of preosteoblast cells on the surface. The PFCL-Click system can be successfully injected into vertebral bodies of rabbit spine and can be monitored by X-ray imaging after incorporating zirconium dioxide (ZrO2) powder. With these unique advantages, this injectable system has promising potential for bone defect repair and other tissue engineering and regenerative medicine applications.

Adult Primary Peripheral PNET/Ewing's Sarcoma of the Cervical and Thoracic Spine.

This case report describes a patient with a rare occurrence of primary spinal intramedullary Ewing's sarcoma (ES) in the cervical and thoracic spine. The older age of disease occurrence, uncommon location in the cervical and thoracic spine, and EWSR1 gene fusion as the basis of diagnosis are unique features of this case. There is no clear protocol for treatment of primary extraskeletal ES of the spine, with controversy between evidence for pursuing surgery versus a combination of radiation and chemotherapy. Our patient was treated with temozolomide chemotherapy for recurrent metastatic disease of primary ES of the spine.

Synergistic Effect of NELL-1 and an Ultra-Low Dose of BMP-2 on Spinal Fusion.

Bone morphogenetic protein 2 (BMP-2) is widely used in spinal fusion but it can cause adverse effects such as ectopic bone and adipose tissue in vivo. Neural epidermal growth factor like-like molecule-1 (NELL-1) has been shown to suppress BMP-2-induced adverse effects. However, no optimum carriers that control both NELL-1 and BMP-2 releases to elicit long-term bioactivity have been developed. In this study, we employed polyelectrolyte complex (PEC) as a control release carrier for NELL-1 and BMP-2. An ultra-low dose of BMP-2 synergistically functioned with NELL-1 on bone marrow mesenchymal stem cells osteogenic differentiation with greater mineralization in vitro. The osteoinductive ability of NELL-1 and an ultra-low dose of BMP-2 in PEC was investigated in rat posterolateral spinal fusion. Our results showed increased fusion rate, bone architecture, and improved bone stiffness at 8 weeks after surgery in the combination groups compared with NELL-1 or BMP-2 alone. Moreover, the formation of ectopic bone and adipose tissue was negligible in all the PEC groups. In summary, dual delivery of NELL-1 and an ultra-low dose of BMP-2 in the PEC control release carrier has greater fusion efficiency compared with BMP-2 alone and could potentially be a better alternative to the currently used BMP-2 treatments for spinal fusion. Impact Statement In this study, polyelectrolyte complex was used to absorb neural epidermal growth factor like-like molecule-1 (NELL-1) and bone morphogenetic protein 2 (BMP-2) to achieve controlled dual release. The addition of NELL-1 significantly reduced the effective dose of BMP-2 to 2.5% of its conventional dose in absorbable collagen sponge, to produce solid spinal fusion without significant adverse effects. This study was the first to identify the efficacy of combination NELL-1 and BMP-2 in a control release carrier in spinal fusion, which could be potentially used clinically to increase fusion rate and avoid the adverse effects commonly associated with conventional BMP-2.