LSD1 inhibition circumvents glucocorticoid-induced muscle wasting of male mice.

Synthetic glucocorticoids (GC), such as dexamethasone, are extensively used to treat chronic inflammation and autoimmune disorders. However, long-term treatments are limited by various side effects, including muscle atrophy. GC activities are mediated by the glucocorticoid receptor (GR), that regulates target gene expression in various tissues in association with cell-specific co-regulators. Here we show that GR and the lysine-specific demethylase 1 (LSD1) interact in myofibers of male mice, and that LSD1 connects GR-bound enhancers with NRF1-associated promoters to stimulate target gene expression. In addition, we unravel that LSD1 demethylase activity is required for triggering starvation- and dexamethasone-induced skeletal muscle proteolysis in collaboration with GR. Importantly, inhibition of LSD1 circumvents muscle wasting induced by pharmacological levels of dexamethasone, without affecting their anti-inflammatory activities. Thus, our findings provide mechanistic insights into the muscle-specific GC activities, and highlight the therapeutic potential of targeting GR co-regulators to limit corticotherapy-induced side effects.

An affirming approach to caring for transgender and gender-diverse youth.

Increasing numbers of youth identify as transgender or gender-diverse (TGD). Many paediatricians and primary care providers (PCPs) will encounter this population in their practice, either for gender-related care or general health needs. This statement is intended as a resource to guide paediatricians and PCPs in implementing an affirming approach to routine health care provision for all youth. Furthermore, it presents information to assist providers in responding to requests for counselling from TGD youth and their families around potential options for medical transition, and in making referrals to specialized services, if desired and relevant. Finally, as demand for gender-affirming care is anticipated to continue to increase, some health care providers (HCPs) may wish to develop the knowledge and skills required to initiate adolescents on hormone-blocking agents and gender-affirming hormones. This document is not intended to be a clinical practice guideline, but will provide foundational information regarding these potential components of gender-affirming care, recognizing that the needs and goals of individual adolescents may or may not include such interventions. Additional resources relevant to developing the expertise required to provide gender-affirming interventions will also be identified.

Une approche d'affirmation pour les soins aux jeunes transgenres et de diverses identités de genre.

Un nombre croissant de jeunes s'identifient comme transgenres ou de diverses identités de genre. De nombreux pédiatres et dispensateurs de soins de première ligne accueilleront cette population dans leur pratique, dans le cadre de soins liés au genre ou de soins de santé généraux. Le présent document de principes se veut une ressource pour orienter les pédiatres et les dispensateurs de soins de première ligne à adopter une approche d'affirmation pour la prestation des soins réguliers à tous les jeunes. De plus, il contient de l'information visant à aider les dispensateurs à répondre aux demandes de conseils des jeunes transgenres et de diverses identités de genre et de leur famille au sujet des possibilités de transition médicale et d'orientation vers des services spécialisés s'ils le désirent et le jugent pertinent. Enfin, on anticipe que la demande de soins d'affirmation de genre continue d'augmenter, et certains dispensateurs de soins peuvent souhaiter acquérir les connaissances et les habiletés nécessaires pour amorcer les inhibiteurs d'hormones et les hormones d'affirmation de genre chez les adolescents. Le présent document ne contient pas de directives cliniques, mais de l'information fondamentale au sujet des divers éléments possibles des soins d'affirmation de genre, tout en reconnaissant que les besoins et les objectifs d'adolescents particuliers n'incluent pas automatiquement de telles interventions. D'autres ressources permettant d'acquérir les compétences nécessaires pour offrir des interventions d'affirmation de genre sont également proposées.

Treatment of Stroke at a Delayed Timepoint with a Repurposed Drug Targeting Sigma 1 Receptors.

Sigma 1 receptors are intracellular chaperone proteins that have been explored as a subacute treatment to enhance post-stroke recovery. We recently identified the antitussive oxeladin as a selective sigma 1 receptor agonist with the ability to stimulate the release of brain-derived neurotrophic factor from neurons in vitro. In this study, we hypothesized that oral oxeladin citrate would stimulate BDNF secretion and improve stroke outcomes when administered to male rats starting 48 h after transient middle cerebral artery occlusion. Oxeladin did not alter blood clotting and crossed the blood brain barrier within 30 min of oral administration. Rats underwent 90 min of transient middle cerebral artery occlusion. Forty-eight hours later rats began receiving daily oxeladin (135 mg/kg) for 11 days. Oxeladin significantly improved neurological function on days 3, 7, and 14 following MCAO. Infarct size was not altered by a single dose, but the final extent of infarct after 14 days was decreased. However, there was no significant reduction in astrogliosis or microgliosis compared to vehicle-treated control rats. In agreement with in vitro studies, oxeladin increased the amount of mature BDNF in the cerebral cortex 2, 6, and 24 h after single oral dose. However, the increase in BDNF did not result in increases in cellular proliferation in the subventricular zone or dentate gyrus when compared to vehicle-treated controls. These results suggest that oxeladin may reduce the extent of infarct expansion in the subacute phase of stroke, although this action does not appear to involve a reduction in inflammation or increased cell proliferation.

An Efficient Protocol for CUT&RUN Analysis of FACS-Isolated Mouse Satellite Cells.

Genome-wide analyses with small cell populations are a major constraint for studies, particularly in the stem cell field. This work describes an efficient protocol for the fluorescence-activated cell sorting (FACS) isolation of satellite cells from the limb muscle, a tissue with a high content of structural proteins. Dissected limb muscles from adult mice were mechanically disrupted by mincing in medium supplemented with dispase and type I collagenase. Upon digestion, the homogenate was filtered through cell strainers, and cells were suspended in FACS buffer. Viability was determined with fixable viability stain, and immunostained satellite cells were isolated by FACS. Cells were lysed with Triton X-100 and released nuclei were bound to concanavalin A magnetic beads. Nucleus/bead complexes were incubated with antibodies against the transcription factor or histone modifications of interest. After washes, nucleus/bead complexes were incubated with protein A-micrococcal nuclease, and chromatin cleavage was initiated with CaCl2. After DNA extraction, libraries were generated and sequenced, and the profiles for genome-wide transcription factor binding and covalent histone modifications were obtained by bioinformatic analysis. The peaks obtained for the various histone marks showed that the binding events were specific for satellite cells. Moreover, known motif analysis unveiled that the transcription factor was bound to chromatin via its cognate response element. This protocol is therefore adapted to study gene regulation in adult mice limb muscle satellite cells.

Measuring severe obesity in pediatrics using body mass index-derived metrics from the Centers for Disease Control and Prevention and World Health Organization: a secondary analysis of CANadian Pediatric Weight management Registry (CANPWR) data.

To examine the (i) relationships between various body mass index (BMI)-derived metrics for measuring severe obesity (SO) over time based the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) references and (ii) ability of these metrics to discriminate children and adolescents based on the presence of cardiometabolic risk factors. In this cohort study completed from 2013 to 2021, we examined data from 3- to 18-year-olds enrolled in the CANadian Pediatric Weight management Registry. Anthropometric data were used to create nine BMI-derived metrics based on the CDC and WHO references. Cardiometabolic risk factors were examined, including dysglycemia, dyslipidemia, and elevated blood pressure. Analyses included Pearson correlations, intraclass correlation coefficients (ICC), and receiver operator characteristic area-under-the-curve (ROC AUC). Our sample included 1,288 participants (n = 666 [52%] girls; n = 874 [68%] white). The prevalence of SO varied from 60-67%, depending on the definition. Most BMI-derived metrics were positively and significantly related to one another (r = 0.45-1.00); ICCs revealed high tracking (0.90-0.94). ROC AUC analyses showed CDC and WHO metrics had a modest ability to discriminate the presence of cardiometabolic risk factors, which improved slightly with increasing numbers of risk factors. Overall, most BMI-derived metrics rated poorly in identifying presence of cardiometabolic risk factors.    Conclusion: CDC BMI percent of the 95th percentile and WHO BMIz performed similarly as measures of SO, although neither showed particularly impressive discrimination. They appear to be interchangeable in clinical care and research in pediatrics, but there is a need for a universal standard. WHO BMIz may be useful for clinicians and researchers from countries that recommend using the WHO growth reference. What is Known: • Severe obesity in pediatrics is a global health issue. • Few reports have evaluated body mass index (BMI)-derived metrics based on the World Health Organization growth reference. What is New: • Our analyses showed that the Centers for Disease Control and Prevention BMI percent of the 95th percentile and World Health Organization (WHO) BMI z-score (BMIz) performed similarly as measures of severe obesity in pediatrics. • WHO BMIz should be a useful metric to measure severe obesity for clinicians and researchers from countries that recommend using the WHO growth reference.

Effects of chronic methamphetamine exposure on rewarding behavior and neurodegeneration markers in adult mice.

Recreational and medical use of stimulants among young adults have gained popularity in the United States over the last decade and their use may increase vulnerability to brain biochemical changes and addictive behaviors. The long-term effects of chronic stimulant exposure in later adulthood have not been fully elucidated.Our study investigated whether chronic exposure to methamphetamine (METH), at a dose designed to emulate human therapeutic dosing for ADHD, would promote biochemical alterations and affect sensitivity to the rewarding effects of subsequent METH dosing.Groups of 3.5-month-old male and female C57BL/6J mice were administered non-contingent intraperitoneal injections of either saline or METH (1.4 mg/kg) twice a day for 1 month (5 days/week). METH (0.5 mg/kg)-induced conditioned place preference (CPP) was tested in mice to determine the effects of previous METH exposure on reward-related behavior. Mice were randomly assigned to Experiment I (males and females) or Experiment II (females only) in which CPP testing was respectively performed either 0.5 or 5 months after the end of METH injections, at ~5 or 10 months old respectively. The midbrain and striatum, regions involved in reward circuit, were assessed for markers associated with neurotoxicity, dopaminergic function, neuroinflammation and epigenetic changes after behavioral testing.Previous exposure to chronic METH did not have significant short-term effects on CPP response but led to a decreased CPP response in 10-month-old females. Previous exposure to METH induced some short-term changes to biochemical markers measured in a brain region and sex-dependent manner, while long-term changes were only observed with GFAP and KDM5C.In conclusion, our data suggest sex- and post-exposure duration-dependent outcomes and warrant further exploration of the long-term neurobehavioral consequences of psychostimulant use in both sexes.

Androgen receptor coordinates muscle metabolic and contractile functions.

BACKGROUND: Androgens are anabolic steroid hormones that exert their function by binding to the androgen receptor (AR). We have previously established that AR deficiency in limb muscles impairs sarcomere myofibrillar organization and decreases muscle strength in male mice. However, despite numerous studies performed in men and rodents, the signalling pathways controlled by androgens via their receptor in skeletal muscles remain poorly understood. METHODS: Male ARskm-/y (n = 7-12) and female ARskm-/- mice (n = 9), in which AR is selectively ablated in myofibres of musculoskeletal tissue, and male AR(i)skm-/y , in which AR is selectively ablated in post-mitotic skeletal muscle myofibres (n = 6), were generated. Longitudinal monitoring of body weight, blood glucose, insulin, lipids and lipoproteins was performed, alongside metabolomic analyses. Glucose metabolism was evaluated in C2C12 cells treated with 5α-dihydrotestosterone (DHT) and the anti-androgen flutamide (n = 6). Histological analyses on macroscopic and ultrastructural levels of longitudinal and transversal muscle sections were conducted. The transcriptome of gastrocnemius muscles from control and ARskm-/y mice was analysed at the age of 9 weeks (P < 0.05, 2138 differentially expressed genes) and validated by RT-qPCR analysis. The AR (4691 peaks with false discovery rate [FDR] < 0.1) and H3K4me2 (47 225 peaks with FDR < 0.05) cistromes in limb muscles were determined in 11-week-old wild-type mice. RESULTS: We show that disrupting the androgen/AR axis impairs in vivo glycolytic activity and fastens the development of type 2 diabetes in male, but not in female mice. In agreement, treatment with DHT increases glycolysis in C2C12 myotubes by 30%, whereas flutamide has an opposite effect. Fatty acids are less efficiently metabolized in skeletal muscles of ARskm-/y mice and accumulate in cytoplasm, despite increased transcript levels of genes encoding key enzymes of beta-oxidation and mitochondrial content. Impaired glucose and fatty acid metabolism in AR-deficient muscle fibres is associated with 30% increased lysine and branched-chain amino acid catabolism, decreased polyamine biosynthesis and disrupted glutamate transamination. This metabolic switch generates ammonia (2-fold increase) and oxidative stress (30% increased H2 O2 levels), which impacts mitochondrial functions and causes necrosis in <1% fibres. We unravel that AR directly activates the transcription of genes involved in glycolysis, oxidative metabolism and muscle contraction. CONCLUSIONS: Our study provides important insights into diseases caused by impaired AR function in musculoskeletal system and delivers a deeper understanding of skeletal muscle pathophysiological dynamics that is instrumental to develop effective treatment for muscle disorders.

Hypoxia-inducible factor 1A inhibition overcomes castration resistance of prostate tumors.

Androgen deprivation therapy (ADT) is a cornerstone of prostate cancer (PCa) management. Although tumors initially regress, many progress to a hormone-independent state termed castration-resistant PCa (CRPC), for which treatment options are limited. We here report that the major luminal cell population in tumors of Pten(i)pe-/- mice, generated by luminal epithelial cell-specific deletion of the tumor suppressor PTEN after puberty, is castration-resistant and that the expression of inflammation and stemness markers is enhanced in persistent luminal cells. In addition, hypoxia-inducible factor 1 (HIF1) signaling, which we have previously demonstrated to be induced in luminal cells of Pten(i)pe-/- mice and to promote malignant progression, is further activated. Importantly, we show that genetic and pharmacological inhibition of HIF1A sensitizes Pten-deficient prostatic tumors to castration and provides durable therapeutic responses. Furthermore, HIF1A inhibition induces apoptotic signaling in human CRPC cell lines. Therefore, our data demonstrate that HIF1A in prostatic tumor cells is a critical factor that enables their survival after ADT, and identify it as a target for CRPC management.

Vitamin D Analogs Bearing C-20 Modifications Stabilize the Agonistic Conformation of Non-Responsive Vitamin D Receptor Variants.

The Vitamin D receptor (VDR) plays a key role in calcium homeostasis, as well as in cell proliferation and differentiation. Among the large number of VDR ligands that have been developed, we have previously shown that BXL-62 and Gemini-72, two C-20-modified vitamin D analogs are highly potent VDR agonists. In this study, we show that both VDR ligands restore the transcriptional activities of VDR variants unresponsive to the natural ligand and identified in patients with rickets. The elucidated mechanisms of action underlying the activities of these C-20-modified analogs emphasize the mutual adaptation of the ligand and the VDR ligand-binding pocket.

Hypoxia-mediated stabilization of HIF1A in prostatic intraepithelial neoplasia promotes cell plasticity and malignant progression.

Prostate cancer (PCa) is a leading cause of cancer-related deaths. The slow evolution of precancerous lesions to malignant tumors provides a broad time frame for preventing PCa. To characterize prostatic intraepithelial neoplasia (PIN) progression, we conducted longitudinal studies on Pten(i)pe-/- mice that recapitulate prostate carcinogenesis in humans. We found that early PINs are hypoxic and that hypoxia-inducible factor 1 alpha (HIF1A) signaling is activated in luminal cells, thus enhancing malignant progression. Luminal HIF1A dampens immune surveillance and drives luminal plasticity, leading to the emergence of cells that overexpress Transglutaminase 2 (TGM2) and have impaired androgen signaling. Elevated TGM2 levels in patients with PCa are associated with shortened progression-free survival after prostatectomy. Last, we show that pharmacologically inhibiting HIF1A impairs cell proliferation and induces apoptosis in PINs. Therefore, our study demonstrates that HIF1A is a target for PCa prevention and that TGM2 is a promising prognostic biomarker of early relapse after prostatectomy.

Dietary genistein and 17ß-estradiol implants differentially influence locomotor and cognitive functions following transient focal ischemia in middle-aged ovariectomized rats at different lengths of estrogen deprivation.

Genistein possesses estrogenic activity and has been considered a potential replacement for estrogen replacement therapy after menopause. In the current study, we investigated the neuroprotective effects of dietary genistein at varied lengths of estrogen deprivation in middle-aged ovariectomized Sprague-Dawley rats under ischemic conditions. Two weeks of treatment with dietary genistein at 42 mg/kg but not 17ß-estradiol implants improved cognitive flexibility (Morris water maze test) after short-term estrogen deprivation (2 weeks) but not long-term estrogen deprivation (12 weeks). 17ß-estradiol implants but not dietary genistein improved locomotor asymmetry (cylinder test) after long-term but not short-term estrogen deprivation. Dietary genistein but not 17ß-estradiol implant improved early phase motor learning (rotarod test) after long-term estrogen deprivation. Neither 17ß-estradiol implant nor dietary genistein reduced infarct size after either short-term or long-term estrogen deprivation. Genistein, however, reduced ionized calcium-binding adaptor molecule-1 (Iba1) expression, a marker of brain inflammation, at the ipsilateral side of stroke injury after short-term but not long-term estrogen deprivation. This study suggests that the neuroprotective effects of dietary genistein on motor and cognitive functions are distinctly influenced by the length of estrogen deprivation following focal ischemia. SIGNIFICANCE: There is an increasing postmenopausal population opting for homeopathic medicines for the management of menopausal symptoms due to the perceived distrust in estrogen use as hormone replacement. Basic and clinical studies support the notion that early, but not delayed, hormone replacement after menopause is beneficial. Furthermore, evidence suggests that delaying hormone replacement augments the detrimental, rather than the beneficial effects of estrogens. Because of the active consideration of soy isoflavones including genistein as alternatives to estrogen replacement, it is necessary to understand the ramifications of soy isoflavones use when their administration is begun at various times after menopause.

Toward Building a Provincial Diabetes Registry of Children and Youth Living With Diabetes in British Columbia, Canada.

OBJECTIVES: Pediatric diabetes health-care providers and decision-makers in British Columbia (BC) have prioritized the creation of a provincial pediatric diabetes clinical registry to improve care quality. Our objective is to build the first BC Pediatrics Diabetes Registry (BC-PDR) for quality improvement and coordination of pediatric diabetes care across the province. METHODS: Patients <19 years of age and diagnosed with diabetes were invited to participate in our study. Recruitment began in 2017 at the BC Children's Hospital (BCCH) and expanded to 6 community-based pediatric diabetes clinics in the Interior Health Authority (HA) in 2019. In response to COVID-19, recruitment shifted from in-person to virtual using an electronic consent system. Patient-level (e.g. age at diabetes onset, ethnicity) and visit-level (e.g. glycated hemoglobin [A1C], blood pressure, diabetes regimen, technology use, medications) data were collected in addition to screening for and presence of diabetes complications. RESULTS: As of January 2021, 635 patients from the BCCH and Interior HA were included in the BC-PDR. From the BCCH, 94% of 590 patients were diagnosed with type 1 diabetes and the median A1C was 7.8% and increased with age. Just under half of the BCCH patients were using insulin pump technology and/or a continuous glucose monitoring system. CONCLUSIONS: Over the last 3 years, we have worked to adapt and operationalize the BC-PDR. The next steps for the BC-PDR include engaging diabetes stakeholders in the development of an electronic benchmarking dashboard along with linkage of the data to patient-reported outcome and experience measures and provincial administrative databases.

Sex differences in neurobehavioral consequences of methamphetamine exposure in adult mice.

RATIONALE: Recreational and medical use of stimulants is increasing, and their use may increase susceptibility to aging and promote neurobehavioral impairments. The long-term consequences of these psychostimulants and how they interact with age have not been fully studied. OBJECTIVES: Our study investigated whether chronic exposure to the prototypical psychostimulant, methamphetamine (METH), at doses designed to emulate human therapeutic dosing, would confer a pro-oxidizing redox shift promoting long-lasting neurobehavioral impairments. METHODS: Groups of 4-month-old male and female C57BL/6 J mice were administered non-contingent intraperitoneal injections of either saline or METH (1.4 mg/kg) twice a day for 4 weeks. Mice were randomly assigned to one experimental group: (i) short-term cognitive assessments (at 5 months), (ii) long-term cognitive assessments (at 9.5 months), and (ii) longitudinal motor assessments (at 5, 7, and 9 months). Brain regions were assessed for oxidative stress and markers of neurotoxicity after behavior testing. RESULTS: Chronic METH exposure induced short-term effects on associative memory, gait speed, dopamine (DA) signaling, astrogliosis in females, and spatial learning and memory, balance, DA signaling, and excitotoxicity in males. There were no long-term effects of chronic METH on cognition; however, it decreased markers of excitotoxicity in the striatum and exacerbated age-associated motor impairments in males. CONCLUSION: In conclusion, cognitive and motor functions were differentially and sex-dependently affected by METH exposure, and oxidative stress did not seem to play a role in the observed behavioral outcomes. Future studies are necessary to continue exploring the long-term neurobehavioral consequences of drug use in both sexes and the relationship between aging and drugs.

TRPC3 shapes the ER-mitochondria Ca2+ transfer characterizing tumour-promoting senescence.

Cellular senescence is implicated in a great number of diseases including cancer. Although alterations in mitochondrial metabolism were reported as senescence drivers, the underlying mechanisms remain elusive. We report the mechanism altering mitochondrial function and OXPHOS in stress-induced senescent fibroblasts. We demonstrate that TRPC3 protein, acting as a controller of mitochondrial Ca2+ load via negative regulation of IP3 receptor-mediated Ca2+ release, is down regulated in senescence regardless of the type of senescence inducer. This remodelling promotes cytosolic/mitochondrial Ca2+ oscillations and elevates mitochondrial Ca2+ load, mitochondrial oxygen consumption rate and oxidative phosphorylation. Re-expression of TRPC3 in senescent cells diminishes mitochondrial Ca2+ load and promotes escape from OIS-induced senescence. Cellular senescence evoked by TRPC3 downregulation in stromal cells displays a proinflammatory and tumour-promoting secretome that encourages cancer epithelial cell proliferation and tumour growth in vivo. Altogether, our results unravel the mechanism contributing to pro-tumour behaviour of senescent cells.

Using measures of metabolic flux to align screening and clinical development: Avoiding pitfalls to enable translational studies.

Screening campaigns, especially those aimed at modulating enzyme activity, often rely on measuring substrate→product conversions. Unfortunately, the presence of endogenous substrates and/or products can limit one's ability to measure conversions. As well, coupled detection systems, often used to facilitate optical readouts, are subject to interference. Stable isotope labeled substrates can overcome background contamination and yield a direct readout of enzyme activity. Not only can isotope kinetic assays enable early screening, but they can also be used to follow hit progression in translational (pre)clinical studies. Herein, we consider a case study surrounding lipid biology to exemplify how metabolic flux analyses can connect stages of drug development, caveats are highlighted to ensure reliable data interpretations. For example, when measuring enzyme activity in early biochemical screening it may be enough to quantify the formation of a labeled product. In contrast, cell-based and in vivo studies must account for variable exposure to a labeled substrate (or precursor) which occurs via tracer dilution and/or isotopic exchange. Strategies are discussed to correct for these complications. We believe that measures of metabolic flux can help connect structure-activity relationships with pharmacodynamic mechanisms of action and determine whether mechanistically differentiated biophysical interactions lead to physiologically relevant outcomes. Adoption of this logic may allow research programs to (i) build a critical bridge between primary screening and (pre)clinical development, (ii) elucidate biology in parallel with screening and (iii) suggest a strategy aimed at in vivo biomarker development.

Surgical Outcomes in Patients With Malignant Small Bowel Obstruction: A National Cohort Study.

OBJECTIVE: The study objectives were to characterize surgical outcomes for malignant small bowel obstruction (MaSBO) as compared to other small bowel obstructions (SBO) and to develop a prediction model for postoperative mortality for MaSBO. SUMMARY BACKGROUND DATA: MaSBO is a morbid complication of advanced cancers for which the optimal management remains undefined. METHODS: Patients who underwent surgery for MaSBO or SBO were identified from the National Surgical Quality Improvement Program (2005-2017). Outcomes [30-day morbidity, unplanned readmissions, mortality, postoperative length of stay (LOS)] were compared between propensity score-matched MaSBO and SBO patients. An internally validated prediction model for mortality in MaSBO patients was developed. RESULTS: Of 46,706 patients, 1612 (3.5%) had MaSBO. Although MaSBO patients were younger than those with SBO (median 63 vs 65 years, P < 0.001), they were otherwise more clinically complex, including a higher proportion with recent weight loss (22.0% vs 4.0%, P < 0.001), severe hypoalbuminemia (18.6% vs 5.2%, P < 0.001), and cytopenias. After matching (N = 1609/group), MaSBO was associated with increased morbidity [odds ratio (OR) 1.2, P = 0.004], but not readmission (OR 1.1, P = 0.48) or LOS (incidence rate ratio 1.0, P = 0.14). The odds of mortality were significantly higher for MaSBO than SBO (OR 3.3, P < 0.001). A risk-score model predicted postoperative mortality for MaSBO with an optimism-adjusted Brier score of 0.114 and area under the curve of 0.735. Patients in the highest-risk category (11.5% of MaSBO population) had a predicted mortality rate of 39.4%. CONCLUSION: Surgery for MaSBO is associated with substantial morbidity and mortality, necessitating careful patient evaluation before operative intervention.