Melatonin ameliorates high glucose-induced autophagy in Schwann cells.

Diabetic neuropathy (DN) is a condition in which nerve fibers are continually exposed to high glucose-induced free radicals. Recent discoveries demonstrated that melatonin is an indole hormone that contributes to neuroprotection through the modulation of autophagy. Herein, this study aims to examine the neuroprotective effects of melatonin on Schwann cells under high glucose conditions. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was used to measure cell viability. The activation of autophagosomes was determined using acridine orange staining (AO). Western blot assay was used to measure the expression of proteins involved in autophagy and endoplasmic reticulum (ER) stress. Our results demonstrated that melatonin at 1 µM has the highest protective effects on high glucose-induced cell death. Melatonin concentrations of 5 and 10 µM were found to be the most effective in reducing autophagy induced by high glucose. Under high glucose conditions, the protein expressions of LC3, ATF4, ATF6, CHOP, PERK and eIF2-α were up-regulated in Schwann cells. However, melatonin attenuated these changes by downregulating LC3 and the ER stress markers ATF4, ATF6, CHOP, PERK and eIF2-α protein expressions in Schwann cells. In conclusion, melatonin alleviates high glucose-induced autophagy in Schwann cells through PERK-eIF2α-ATF4-CHOP signaling pathways.

Sugar transporter Slc37a2 regulates bone metabolism in mice via a tubular lysosomal network in osteoclasts.

Osteoclasts are giant bone-digesting cells that harbor specialized lysosome-related organelles termed secretory lysosomes (SLs). SLs store cathepsin K and serve as a membrane precursor to the ruffled border, the osteoclast's 'resorptive apparatus'. Yet, the molecular composition and spatiotemporal organization of SLs remains incompletely understood. Here, using organelle-resolution proteomics, we identify member a2 of the solute carrier 37 family (Slc37a2) as a SL sugar transporter. We demonstrate in mice that Slc37a2 localizes to the SL limiting membrane and that these organelles adopt a hitherto unnoticed but dynamic tubular network in living osteoclasts that is required for bone digestion. Accordingly, mice lacking Slc37a2 accrue high bone mass owing to uncoupled bone metabolism and disturbances in SL export of monosaccharide sugars, a prerequisite for SL delivery to the bone-lining osteoclast plasma membrane. Thus, Slc37a2 is a physiological component of the osteoclast's unique secretory organelle and a potential therapeutic target for metabolic bone diseases.

Patients' Perception and Satisfaction on Neck and Shoulder Imbalance in Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To evaluate the perception and satisfaction among adolescent idiopathic scoliosis (AIS) patients on Neck Tilt with Medial Shoulder Imbalance and Lateral Shoulder Imbalance. METHODS: Lenke 1 and 2 AIS patients were stratified into 6 groups of preoperative/ postoperative Balanced (B), Lateral Shoulder Imbalance (LSI) (>2 cm), and Neck Tilt with Medial Shoulder Imbalance (NT) (Grade 3). Patients were interviewed using Modified Neck and Shoulder Appearance and SRS-22r questionnaires. T1 tilt, Cervical Axis (CA), Clavicle Angle (Cla-A) and Radiographic Shoulder Height (RSH) were measured. RESULTS: A total of 120 Lenke 1 and 2 AIS patients were recruited. NT patients were aware and unhappy with their abnormal neck with medial shoulder appearances (P < .001). Similarly, LSI patients were aware and unhappy with their abnormal lateral shoulder appearances (P < .001). NT group had larger preoperative/ postoperative T1 tilt (9.2 ± 5.0°; 9.5 ± 5.3°) and CA (4.6 ± 3.1°; 7.0 ± 2.0°) (P < .01). LSI group had larger preoperative/ postoperative Cla-A (4.8 ± 2.8°; 4.0 ± 1.3°) and RSH (20.1 ± 9.4 mm; 17.0 ± 6.6 mm) (P < .001). Postoperative B group scored higher in overall SRS-22r scores, self-image and satisfaction domains (4.2 ± 0.3; 4.0 ± 0.5; 4.4 ± 0.5) while preoperative LSI scored the lowest comparatively (3.5 ± 0.4; 2.4 ± 0.5; 3.3 ± 0.5) (P < .001). CONCLUSION: NT and LSI were major concerns among AIS patients. Both NT and LSI groups were unhappy with their appearances. NT group had larger T1 tilt/ CA whereas LSI group had larger Cla-A/ RSH. Postoperative B group scored higher in overall SRS-22r scores, self-image and satisfaction domains.

Preoperative "Cervical Axis" Deviation Increases the Risk of Distal Adding-On Following Surgery in Lenke 1 and 2 Adolescent Idiopathic Scoliosis Patients.

STUDY DESIGN: Retrospective. PURPOSE: To evaluate the relationship between shoulder/ neck imbalance with distal adding-on phenomenon and to identify other risk factors in Lenke 1 and 2 (non-AR curves) adolescent idiopathic scoliosis (AIS) patients. METHODS: 100 Lenke 1 and 2 AIS patients with lowest instrumented vertebra (LIV) cephalad to or at L1 were recruited. Medial shoulder/ neck balance was represented by T1-tilt and cervical axis (CA). Lateral shoulder balance was represented by clavicle angle (Cla-A) and radiographic shoulder height (RSH). Distal adding-on phenomenon was diagnosed when there was disc wedging below LIV of >5o at final follow-up. Predictive factors and odds ratio were derived using univariate and multivariate logistic regression analysis. RESULTS: Mean age of this cohort was 15.9 ± 4.4 years. Mean follow-up duration was 30.9 ± 9.6 months. Distal adding-on phenomenon occurred in 19 patients (19.0%). Only Risser grade, preoperative CA and final follow-up lumbar Cobb angle were the independent factors. A positive preoperative CA deviation increased the odds of distal adding-on by 5.4 times (95% CI 1.34-21.51, P = 0.018). The mean immediate postoperative T1-tilt, CA, RSH and Cla-A were comparable between the group with distal adding-on and the group without. CONCLUSION: Distal adding-on phenomenon occurred in 19.0% of patients. Preoperative "Cervical Axis" was an important factor and it increased the risk of distal adding-on by 5.4 times. Other significant predictive factors were Risser grade and lumbar Cobb angle at final follow-up. Immediate postoperative shoulder or neck imbalance was not a significant factor for postoperative distal adding-on phenomenon.

Melatonin Induces Autophagy via Reactive Oxygen Species-Mediated Endoplasmic Reticulum Stress Pathway in Colorectal Cancer Cells.

Even though an increasing number of anticancer treatments have been discovered, the mortality rates of colorectal cancer (CRC) have still been high in the past few years. It has been discovered that melatonin has pro-apoptotic properties and counteracts inflammation, proliferation, angiogenesis, cell invasion, and cell migration. In previous studies, melatonin has been shown to have an anticancer effect in multiple tumors, including CRC, but the underlying mechanisms of melatonin action on CRC have not been fully explored. Thus, in this study, we investigated the role of autophagy pathways in CRC cells treated with melatonin. In vitro CRC cell models, HT-29, SW48, and Caco-2, were treated with melatonin. CRC cell death, oxidative stress, and autophagic vacuoles formation were induced by melatonin in a dose-dependent manner. Several autophagy pathways were examined, including the endoplasmic reticulum (ER) stress, 5'-adenosine monophosphate-activated protein kinase (AMPK), phosphoinositide 3-kinase (PI3K), serine/threonine-specific protein kinase (Akt), and mammalian target of rapamycin (mTOR) signaling pathways. Our results showed that melatonin significantly induced autophagy via the ER stress pathway in CRC cells. In conclusion, melatonin demonstrated a potential as an anticancer drug for CRC.

Osteal macrophages support osteoclast-mediated resorption and contribute to bone pathology in a postmenopausal osteoporosis mouse model.

Osteal macrophages (osteomacs) support osteoblast function and promote bone anabolism, but their contribution to osteoporosis has not been explored. Although mouse ovariectomy (OVX) models have been repeatedly used, variation in strain, experimental design and assessment modalities have contributed to no single model being confirmed as comprehensively replicating the full gamut of osteoporosis pathological manifestations. We validated an OVX model in adult C3H/HeJ mice and demonstrated that it presents with human postmenopausal osteoporosis features with reduced bone volume in axial and appendicular bone and bone loss in both trabecular and cortical bone including increased cortical porosity. Bone loss was associated with increased osteoclasts on trabecular and endocortical bone and decreased osteoblasts on trabecular bone. Importantly, this OVX model was characterized by delayed fracture healing. Using this validated model, we demonstrated that osteomacs are increased post-OVX on both trabecular and endocortical bone. Dual F4/80 (pan-macrophage marker) and tartrate-resistant acid phosphatase (TRAP) staining revealed osteomacs frequently located near TRAP+ osteoclasts and contained TRAP+ intracellular vesicles. Using an in vivo inducible macrophage depletion model that does not simultaneously deplete osteoclasts, we observed that osteomac loss was associated with elevated extracellular TRAP in bone marrow interstitium and increased serum TRAP. Using in vitro high-resolution confocal imaging of mixed osteoclast-macrophage cultures on bone substrate, we observed macrophages juxtaposed to osteoclast basolateral functional secretory domains scavenging degraded bone byproducts. These data demonstrate a role for osteomacs in supporting osteoclastic bone resorption through phagocytosis and sequestration of resorption byproducts. Overall, our data expose a novel role for osteomacs in supporting osteoclast function and provide the first evidence of their involvement in osteoporosis pathogenesis. © 2021 American Society for Bone and Mineral Research (ASBMR).

Membrane Transport Proteins in Osteoclasts: The Ins and Outs.

During bone resorption, the osteoclast must sustain an extraordinarily low pH environment, withstand immense ionic pressures, and coordinate nutrient and waste exchange across its membrane to sustain its unique structural and functional polarity. To achieve this, osteoclasts are equipped with an elaborate set of membrane transport proteins (pumps, transporters and channels) that serve as molecular 'gatekeepers' to regulate the bilateral exchange of ions, amino acids, metabolites and macromolecules across the ruffled border and basolateral domains. Whereas the importance of the vacuolar-ATPase proton pump and chloride voltage-gated channel 7 in osteoclasts has long been established, comparatively little is known about the contributions of other membrane transport proteins, including those categorized as secondary active transporters. In this Special Issue review, we provide a contemporary update on the 'ins and outs' of membrane transport proteins implicated in osteoclast differentiation, function and bone homeostasis and discuss their therapeutic potential for the treatment of metabolic bone diseases.

Dual attending surgeon strategy learning curve in single-staged posterior spinal fusion (PSF) surgery for 415 idiopathic scoliosis (IS) cases.

BACKGROUND CONTEXT: The implementation of a dual attending surgeon strategy had improved perioperative outcomes of idiopathic scoliosis (IS) patients. Nevertheless, the learning curve of a dual attending surgeon practice in single-staged posterior spinal fusion (PSF) surgery has not been established. OBJECTIVE: To evaluate the surgical learning curve of a dual attending surgeon strategy in IS patients. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: 415 IS patients (Cobb angle <90°) who underwent PSF using a dual attending surgeon strategy OUTCOME MEASURES: Primary outcomes included operative time, total blood loss, allogenic blood transfusion requirement, length of hospital stay and perioperative complication rate. METHODS: Regression analysis using Locally Weighted Scatterplot Smoothing (LOWESS) method was applied to create the best-fit-curve between case number versus operative time and total blood loss in identifying cut-off points for the learning curve. RESULTS: The mean Cobb angle was 60.8±10.8°. Mean operative time was 134.4±32.1 minutes and mean total blood loss was 886.0±450.6 mL. The mean length of hospital stay was 3.0±1.6 days. The learning curves of a dual attending surgeon strategy in this study were established at the 115th case (operative time) and 196th case (total blood loss) respectively (p<.001). In comparison of cases before and after the cut-off points, mean operative time reduced significantly from 147.2±36.5 minutes to 129.5±28.9 minutes and mean total blood loss reduced significantly from 1015.1±506.6 mL to 770.4±357.3 mL (p<.001). No allogenic blood transfusion was required and there were 7 perioperative complications (n=7/415, 1.7%) recorded. CONCLUSION: The learning curve of a dual surgeon strategy in single-staged PSF surgery based on operative time and total blood loss were established at 115th case and 196th case respectively (p<.001).

Osteoclasts recycle via osteomorphs during RANKL-stimulated bone resorption.

Osteoclasts are large multinucleated bone-resorbing cells formed by the fusion of monocyte/macrophage-derived precursors that are thought to undergo apoptosis once resorption is complete. Here, by intravital imaging, we reveal that RANKL-stimulated osteoclasts have an alternative cell fate in which they fission into daughter cells called osteomorphs. Inhibiting RANKL blocked this cellular recycling and resulted in osteomorph accumulation. Single-cell RNA sequencing showed that osteomorphs are transcriptionally distinct from osteoclasts and macrophages and express a number of non-canonical osteoclast genes that are associated with structural and functional bone phenotypes when deleted in mice. Furthermore, genetic variation in human orthologs of osteomorph genes causes monogenic skeletal disorders and associates with bone mineral density, a polygenetic skeletal trait. Thus, osteoclasts recycle via osteomorphs, a cell type involved in the regulation of bone resorption that may be targeted for the treatment of skeletal diseases.

Learning Curve for a Dual Attending Surgeon Strategy in Posterior Spinal Fusion (PSF): An Analysis of 105 Severe Adolescent Idiopathic Scoliosis Patients (Cobb Angle ≥90°).

STUDY DESIGN: Retrospective study. OBJECTIVE: To assess the learning curve of a dual attending surgeon strategy in severe adolescent idiopathic scoliosis patients. SUMMARY OF BACKGROUND DATA: The advantages of a dual attending surgeon strategy in improving the perioperative outcome in scoliosis surgery had been reported. However, the learning curve of this strategy in severe scoliosis had not been widely studied. METHODS: A total of 105 patients with adolescent idiopathic scoliosis with Cobb angle of 90° or greater, who underwent posterior spinal fusion using a dual attending surgeon strategy were recruited. Primary outcomes were operative time, total blood loss, allogeneic blood transfusion requirement, length of hospital stay from time of operation and perioperative complications. Cases were sorted chronologically into group 1: cases 1 to 35, group 2: cases 36 to 70, and group 3: case 71 to 105. Mean operative time (≤193.3 min), total blood loss (≤1612.2 mL), combination of both and allogeneic blood transfusion were the selected criteria for receiver operating characteristic analysis of the learning curve. RESULTS: The mean Cobb angle was 104.5°â€Š±â€Š12.3°. The operative time, total blood loss, and allogeneic blood transfusion requirement reduced significantly for group 1 (220.6 ±â€Š54.8 min; 2011.3 ±â€Š881.8 mL; 12 cases) versus group 2 (183.6 ±â€Š36.7 min; 1481.6 ±â€Š1035.5 mL; 3 cases) and group 1 versus group 3 (175.6 ±â€Š38.4 min; 1343.7 ±â€Š477.8 mL; 3 cases) (P < 0.05). There were six perioperative complications. Fifty-seven cases were required to achieve the preset criteria (mean operative time and mean total blood loss) (area under the curve 0.740; P < 0.001; sensitivity 0.675; specificity 0.662). CONCLUSION: There was significant improvement in operative time and total blood loss when comparing group 1 versus group 2 and group 1 versus group 3. The cut-off point for the learning curve was 57 cases when the preset criteria were fulfilled (≤193.3 min operative time and ≤1612.2 mL of total blood loss).Level of Evidence: 4.

Perioperative outcome of severe rigid idiopathic scoliosis: Single-staged posterior spinal fusion utilizing a dual attending surgeon strategy. A report of 41 patients.

PURPOSE: Various surgical strategies including combined approach and spinal osteotomies in severe rigid scoliosis had been reported with significant perioperative complication rates. The use of single-staged posterior spinal fusion (PSF) utilizing a dual attending surgeon strategy for severe rigid scoliosis has not been widely reported. METHODS: This was a retrospective study aimed to evaluate the perioperative outcome of single-staged PSF in severe rigid idiopathic scoliosis patients (Cobb angle ≥90° and ≤30% flexibility). Forty-one patients with severe rigid idiopathic scoliosis who underwent single-staged PSF were included. The perioperative outcome parameters were operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, transfusion rate, patient-controlled anesthesia morphine usage, length of postoperative hospital stay, and perioperative complications. Radiological parameters included preoperative and postoperative Cobb angle, correction rate, side-bending flexibility, and side-bending correction index. RESULTS: The mean age was 16.9 ± 5.6 years. The mean preoperative Cobb angle was 110.8 ± 12.1° with mean flexibility of 23.1 ± 6.3%. The mean operation duration was 215.5 ± 45.2 min with mean blood loss of 1752.6 ± 830.5 mL. The allogeneic blood transfusion rate was 24.4%. The mean postoperative hospital stay was 76.9 ± 26.7 h. The mean postoperative Cobb angle and correction rate were 54.4 ± 12.8° and 50.9 ± 10.1%, respectively. The readmission rate in this cohort was 2.4%. Four perioperative complications were documented (9.8%), one somatosensory evoke potential signal loss, one superficial infection, one lung collapse, and one superior mesenteric artery syndrome. CONCLUSIONS: Severe rigid idiopathic scoliosis treated with single-staged PSF utilizing a dual attending surgeon strategy demonstrated an average correction rate of 50.9%, operation duration of 215.5 min, and postoperative hospital stay of 76.9 h with a 9.8% perioperative complication rate.

Parents'/Patients' Perception of the Informed Consent Process and Surgeons Accountability in Corrective Surgery for Adolescent Idiopathic Scoliosis: A Prospective Study.

STUDY DESIGN: Prospective study. OBJECTIVE: To determine the parents'/patients' perception on the informed consent process prior to posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) patients. SUMMARY OF BACKGROUND DATA: Understanding parents/patients perspective on the process is important in order to achieve the goal of consent and prevent medico-legal implications. METHODS: Fifty AIS patients operated between August 2019 and November 2019 were prospectively recruited. Parents'/patients' perceptions on three sections were evaluated: the process of the informed consent, specific operative risk which they were most concerned with and the accountability of surgeons for the surgical risks. These data were ranked and scored using a 5-point Likert Scale. Preferences were reported in mean and standard deviation. Differences in terms of preferences were studied using One-way analysis of variance (ANOVA) analysis and deemed significant when P < 0.05. RESULTS: There were 30 females (60.0%) and 20 males (40.0%) with a mean age of 41.8 ±â€Š10.6 years. Majority of parents/patients preferred the inform consent to be explained more than once (P = 0.021), once during clinic consultation and once during admission (4.2 ±â€Š1.0). Consent taking by both attending surgeons was preferred (4.5 ±â€Š0.6) compared with other healthcare providers, P < 0.001. Death (60.0%) and neurological deficit (30.0%) were the two most concerned surgical risks. Parents/patients would still hold the surgeon accountable for any complications despite signing the informed consent and they felt that surgeons were directly responsible for screw-related injuries (3.9 ±â€Š0.9), neurological injury (3.8 ±â€Š0.9), and intraoperative bleeding (3.7 ±â€Š0.9). CONCLUSION: Parents/patients preferred the attending surgeons to personally explain the informed consent, more than once with the use of visual aid. They would still hold the surgeons accountable when complications occur despite acceptance of the informed consent. LEVEL OF EVIDENCE: 2.

Recent advances in tau-directed immunotherapy against Alzheimer's disease: an overview of pre-clinical and clinical development.

Alzheimer's disease (AD) has been a worldwide concern for many years now. This is due to the fact that AD is an irreversible and progressive neurodegenerative disease that affects quality of life. Failure of some Phase II/III clinical trials in AD targeting accumulation of ß-amyloid in the brain has led to an increase in interest in studying alternative treatments against tubulin-associated unit (Tau) pathology. These alternative treatments include active and passive immunisation. Based on numerous studies, Tau is reported as a potential immunotherapeutic target for tauopathy-related diseases including AD. Accumulation and aggregation of hyperphosphorylated Tau as neuropil threads and neurofibrillary tangles (NFT) are pathological hallmarks of AD. Both active and passive immunisation targeting Tau protein have shown the capabilities to decrease or prevent Tau pathology and improve either motor or cognitive impairment in various animal models. In this review, we summarise recent advances in active and passive immunisation targeting pathological Tau protein, and will discuss with data obtained from both animal and human trials. Together, we give a brief overview about problems being encountered in these immunotherapies.

A Positive (+ve) Postoperative Upper Instrumented Vertebra Tilt Angle (≥0°) Significantly Increases the Risk of Medial Shoulder and Neck Imbalance in Lenke 1 and 2 Adolescent Idiopathic Scoliosis Patients.

STUDY DESIGN: Retrospective study. OBJECTIVE: To investigate the relationship between a +ve postoperative Upper Instrumented Vertebra (UIV) (≥0°) tilt angle and the risk of medial shoulder/neck and lateral shoulder imbalance among Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients following Posterior Spinal Fusion. SUMMARY OF BACKGROUND DATA: Current UIV selection strategy has poor correlation with postoperative shoulder balance. The relationship between a +ve postoperative UIV tilt angle and the risk of postoperative shoulder and neck imbalance was unknown. METHODS: One hundred thirty-six Lenke 1 and 2 AIS patients with minimum 2 years follow-up were recruited. For medial shoulder and neck balance, patients were categorized into positive (+ve) imbalance (≥+4°), balanced, or negative (-ve) imbalance (≤-4°) groups based on T1 tilt angle/Cervical Axis measurement. For lateral shoulder balance, patients were classified into +ve imbalance (≥+3°) balanced, and -ve imbalance (≤-3°) groups based on Clavicle Angle (Cla-A) measurement. Linear regression analysis identified the predictive factors for shoulder/neck imbalance. Logistic regression analysis calculated the odds ratio of shoulder/neck imbalance for patients with +ve postoperative UIV tilt angle. RESULTS: Postoperative UIV tilt angle and preoperative T1 tilt angle were predictive of +ve medial shoulder imbalance. Postoperative UIV tilt angle and postoperative PT correction were predictive of +ve neck imbalance. Approximately 51.6% of patients with +ve medial shoulder imbalance had +ve postoperative UIV tilt angle. Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance and 3.3 times increased odds of developing +ve neck imbalance. Postoperative UIV tilt angle did not predict lateral shoulder imbalance. CONCLUSION: Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance (T1 tilt angle ≥+4°) and 3.3 times increased odds of developing +ve neck imbalance (cervical axis ≥+4°). LEVEL OF EVIDENCE: 4.

Perioperative Outcome of Severe Idiopathic Scoliosis (Cobb Angle ≥ 90°): Is There Any Difference Between "Daytime" Versus "After-hours" Surgeries?

STUDY DESIGN: Retrospective study from a prospectively collected database. OBJECTIVE: To compare the perioperative outcome between after-hours and daytime surgery carried out by a dedicated spinal deformity team for severe Idiopathic Scoliosis (IS) patients with Cobb angle ≥ 90°. SUMMARY OF BACKGROUND DATA: There were concerns that after-hours corrective surgeries in severe IS have higher morbidity compared to daytime surgeries. METHODS: Seventy-one severe IS patients who underwent single-staged Posterior Spinal Fusion (PSF) were included. Surgeries performed between 08:00H and 16:59H were classified as "daytime" group and surgeries performed between 17:00H and 06:00H were classified as "after-hours" group. Perioperative outcome parameters were average operation start time and end time, operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, blood transfusion rate, total patient-controlled anesthesia (PCA) morphine usage, length of postoperative hospitalization, and complications. Radiological variables assessed were preoperative and postoperative Cobb angle, side bending flexibility, number of fusion levels, number of screws used, Correction Rate, and Side Bending Correction Index. RESULTS: Thirty patients were operated during daytime and 41 patients were operated after-hours. The mean age was 16.1 ±â€Š5.8 years old. The mean operation start time for daytime group was 11:31 ±â€Š2:45H versus 19:10 ±â€Š1:24H for after-hours group. There were no significant differences between both groups in the operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, postoperative hemoglobin, hemoglobin drift, transfusion rate, length of postoperative hospitalization, postoperative Cobb angle, Correction Rate, and Side Bending Correction Index. There were four complications (1 SSEP loss, 1 massive blood loss, and 2 superficial wound infections) with no difference between daytime and after-hours group. CONCLUSION: After-hours elective spine deformity corrective surgeries in healthy ambulatory patients with severe IS performed by a dedicated spinal deformity team using dual attending surgeon strategy were as safe as those performed during daytime. LEVEL OF EVIDENCE: 4.

Staphylococcus aureus Infects Osteoclasts and Replicates Intracellularly.

Osteomyelitis (OM), or inflammation of bone tissue, occurs most frequently as a result of bacterial infection and severely perturbs bone structure. OM is predominantly caused by Staphylococcus aureus, and even with proper treatment, OM has a high rate of recurrence and chronicity. While S. aureus has been shown to infect osteoblasts, it remains unclear whether osteoclasts (OCs) are also a target of intracellular infection. Here, we demonstrate the ability of S. aureus to intracellularly infect and divide within OCs. OCs were differentiated from bone marrow macrophages (BMMs) by exposure to receptor activator of nuclear factor kappa-B ligand (RANKL). By utilizing an intracellular survival assay and flow cytometry, we found that at 18 h postinfection the intracellular burden of S. aureus increased dramatically in cells with at least 2 days of RANKL exposure, while the bacterial burden decreased in BMMs. To further explore the signals downstream of RANKL, we manipulated factors controlling OC differentiation, NFATc1 and alternative NF-κB, and found that intracellular bacterial growth correlates with NFATc1 levels in RANKL-treated cells. Confocal and time-lapse microscopy in mature OCs showed a range of intracellular infection that correlated inversely with S. aureus-phagolysosome colocalization. The propensity of OCs to become infected, paired with their diminished bactericidal capacity compared to BMMs, could promote OM progression by allowing S. aureus to evade initial immune regulation and proliferate at the periphery of lesions where OCs are most abundant.IMPORTANCE The inflammation of bone tissue is called osteomyelitis, and most cases are caused by an infection with the bacterium Staphylococcus aureus To date, the bone-building cells, osteoblasts, have been implicated in the progression of these infections, but not much is known about how the bone-resorbing cells, osteoclasts, participate. In this study, we show that S. aureus can infect osteoclasts and proliferate inside these cells, whereas bone-residing macrophages, immune cells related to osteoclasts, destroy the bacteria. These findings elucidate a unique role for osteoclasts to harbor bacteria during infection, providing a possible mechanism by which bacteria could evade destruction by the immune system.

Sfrp4 repression of the Ror2/Jnk cascade in osteoclasts protects cortical bone from excessive endosteal resorption.

Loss-of-function mutations in the Wnt inhibitor secreted frizzled receptor protein 4 (SFRP4) cause Pyle's disease (OMIM 265900), a rare skeletal disorder characterized by wide metaphyses, significant thinning of cortical bone, and fragility fractures. In mice, we have shown that the cortical thinning seen in the absence of Sfrp4 is associated with decreased periosteal and endosteal bone formation and increased endocortical resorption. While the increase in Rankl/Opg in cortical bone of mice lacking Sfrp4 suggests an osteoblast-dependent effect on endocortical osteoclast (OC) activity, whether Sfrp4 can cell-autonomously affect OCs is not known. We found that Sfrp4 is expressed during bone marrow macrophage OC differentiation and that Sfrp4 significantly suppresses the ability of early and late OC precursors to respond to Rankl-induced OC differentiation. Sfrp4 deletion in OCs resulted in activation of canonical Wnt/ß-catenin and noncanonical Wnt/Ror2/Jnk signaling cascades. However, while inhibition of canonical Wnt/ß-catenin signaling did not alter the effect of Sfrp4 on OCgenesis, blocking the noncanonical Wnt/Ror2/Jnk cascade markedly suppressed its regulation of OC differentiation in vitro. Importantly, we report that deletion of Ror2 exclusively in OCs (CtskCreRor2fl/fl ) in Sfrp4 null mice significantly reversed the increased number of endosteal OCs seen in these mice and reduced their cortical thinning. Altogether, these data show autocrine and paracrine effects of Sfrp4 in regulating OCgenesis and demonstrate that the increase in endosteal OCs seen in Sfrp4-/- mice is a consequence of noncanonical Wnt/Ror2/Jnk signaling activation in OCs overriding the negative effect that activation of canonical Wnt/ß-catenin signaling has on OCgenesis.

Enantiomeric pairs of ternary copper(ii) complexes and their aldol-type condensation products: synthesis, characterization, and anticancer and epigenetic properties.

Chiral enantiomers [Cu(phen)(l-ser)(H2O)]NO31 and [Cu(phen)(d-ser)(H2O)]NO32 (ser = serinato) underwent aldol-type condensation with formaldehyde, with retention of chirality, to yield their respective enantiomeric ternary copper(ii) complexes, viz. l- and d-[Cu(phen)(OCA)(H2O)]NO3·xH2O (3 and 4; phen = 1,10-phenanthroline; OCA = oxazolidine-4-carboxylate; x = 1/2, 0-2) respectively. These chiral complexes were characterized by FTIR, elemental analysis, circular dichroism, UV-visible spectroscopy, fluorescence spectroscopy (FL), molar conductivity measurement, ESI-MS and X-ray crystallography. The crystal structures of 1 and 3 showed both the cationic complexes to have a square pyramidal geometry. These complexes were about nine fold more potent than cisplatin against metastatic MDA-MB-231 breast cancer cells, inducing apoptotic cell death via ROS generation and a massive drop in mitochondrial membrane potential. The results of monitoring EZH1, EZH2 and H3K27me3 revealed that the mode of action of 1-4 also involved the downregulation of EZH2 and it seemed to be independent of the H3K27me3 status.

Membrane trafficking in osteoclasts and implications for osteoporosis.

Osteoclasts are large multinucleated cells exquisitely adapted to resorb bone matrix. Like other eukaryotes, osteoclasts possess an elaborate ensemble of intracellular organelles through which solutes, proteins and other macromolecules are trafficked to their target destinations via membrane-bound intermediaries. During bone resorption, membrane trafficking must be tightly regulated to sustain the structural and functional polarity of the osteoclasts' membrane domains. Of these, the ruffled border (RB) is most characteristic, functioning as the osteoclasts' secretory apparatus. This highly convoluted organelle is classically considered to be formed by the targeted fusion of acidic vesicles with the bone-facing plasma membrane. Emerging findings disclose new evidence that the RB is far more complex than previously envisaged, possessing discrete subdomains that are serviced by several intersecting endocytic, secretory, transcytotic and autophagic pathways. Bone-resorbing osteoclasts therefore serve as a unique model system for studying polarized membrane trafficking. Recent advances in high-resolution microscopy together with the convergence of genetic and cell biological studies in humans and in mice have helped illuminate the major membrane trafficking pathways in osteoclasts and unmask the core molecular machinery that governs these distinct vesicle transport routes. Among these, small Rab GTPases, their binding partners and members of the endocytic sorting nexin family have emerged as critical regulators. This mini review summarizes our current understanding of membrane trafficking in osteoclasts, the key molecular participants, and discusses how these transport machinery may be exploited for the development of new therapies for metabolic disorders of bone-like osteoporosis.