Mitochondrial DNA levels in perfusate and bile during ex vivo normothermic machine correspond with donor liver quality.

Ex vivo normothermic machine perfusion (NMP) preserves donor organs and permits real-time assessment of allograft health, but the most effective indicators of graft viability are uncertain. Mitochondrial DNA (mtDNA), released consequent to traumatic cell injury and death, including the ischemia-reperfusion injury inherent in transplantation, may meet the need for a biomarker in this context. We describe a real time PCR-based approach to assess cell-free mtDNA during NMP as a universal biomarker of allograft quality. Measured in the perfusate fluid of 29 livers, the quantity of mtDNA correlated with metrics of donor liver health including International Normalized Ratio (INR), lactate, and warm ischemia time, and inversely correlated with inferior vena cava (IVC) flow during perfusion. Our findings endorse mtDNA as a simple and rapidly measured feature that can inform donor liver health, opening the possibility to better assess livers acquired from extended criteria donors to improve organ supply.

Cyclosporine A Does Not Mitigate Liver Ischemia/Reperfusion Injury in an Ex Vivo Porcine Model of Donation After Circulatory Death.

BACKGROUND Ischemia/reperfusion injury (IRI) is an inherent problem in organ transplantation, owing to the obligate period of ischemia that organs must endure. Cyclosporine A (CsA), though better know as an immunosuppressant, has been shown to mitigate warm IRI in a variety of organ types, including the liver. However, there is little evidence for CsA in preventing hepatic IRI in the transplant setting. MATERIAL AND METHODS In the present study, we tested the effect of CsA on hepatic IRI in a large-animal ex vivo model of donation after circulatory death (DCD). Porcine donors were pre-treated with either normal saline control or 20 mg/kg of CsA. Animals were subject to either 45 or 60 minutes of warm ischemia before hepatectomy, followed by 2 or 4 hours of cold storage prior to reperfusion on an ex vivo circuit. Over the course of a 12-hour perfusion, perfusion parameters were recorded and perfusate samples and biopsies were taken at regular intervals. RESULTS Peak perfusate lactate dehydrogenase was significantly decreased in the lower-ischemia group treated with CsA compared to the untreated group (4220 U/L [3515-5815] vs 11 305 [10 100-11 674]; P=0.023). However, no difference was seen between controls and CsA-treated groups on other parameters in perfusate alanine or asparagine aminotransferase (P=0.912, 0.455, respectively). Correspondingly, we found no difference on midpoint histological injury score (P=0.271). CONCLUSIONS We found minimal evidence that CsA is protective against hepatic IRI in our DCD model.

Long-term outcomes after normothermic machine perfusion in liver transplantation-Experience at a single North American center.

Normothermic machine perfusion (NMP) has emerged as a valuable tool in the preservation of liver allografts before transplantation. Randomized trials have shown that replacing static cold storage (SCS) with NMP reduces allograft injury and improves graft utilization. The University of Alberta's liver transplant program was one of the early adopters of NMP in North America. Herein, we describe our 7-year experience applying NMP to extend preservation time in liver transplantation using a "back-to-base" approach. From 2015 to 2021, 79 livers were transplanted following NMP, compared with 386 after SCS only. NMP livers were preserved for a median time of minutes compared with minutes in the SCS cohort (P < .0001). Despite this, we observed significantly improved 30-day graft survival (P = .030), although there were no differences in long-term patient survival, major complications, or biliary or vascular complications. We also found that although SCS time was strongly associated with increased graft failure at 1 year in the SCS cohort (P = .006), there was no such association among NMP livers (P = .171). Our experience suggests that NMP can safely extend the total preservation time of liver allografts without increasing complications.

Pancreas and Islet Transplantation: Comparative Outcome Analysis of a Single-centre Cohort Over 20-years.

OBJECTIVE: To provide the largest single-center analysis of islet (ITx) and pancreas (PTx) transplantation. SUMMARY BACKGROUND DATA: Studies describing long-term outcomes with ITx and PTx are scarce. METHODS: We included adults undergoing ITx (n=266) and PTx (n=146) at the University of Alberta from January 1999 to October 2019. Outcomes include patient and graft survival, insulin independence, glycemic control, procedure-related complications, and hospital readmissions. Data are presented as medians (interquartile ranges, IQR) and absolute numbers (percentages, %) and compared using Mann-Whitney and χ2 tests. Kaplan-Meier estimates, Cox proportional hazard models and mixed main effects models were implemented. RESULTS: Crude mortality was 9.4% and 14.4% after ITx and PTx, respectively ( P= 0.141). Sex-adjusted and age-adjusted hazard-ratio for mortality was 2.08 (95% CI, 1.04-4.17, P= 0.038) for PTx versus ITx. Insulin independence occurred in 78.6% and 92.5% in ITx and PTx recipients, respectively ( P= 0.0003), while the total duration of insulin independence was 2.1 (IQR 0.8-4.6) and 6.7 (IQR 2.9-12.4) year for ITx and PTx, respectively ( P= 2.2×10 -22 ). Graft failure ensued in 34.2% and 19.9% after ITx and PTx, respectively ( P =0.002). Glycemic control improved for up to 20-years post-transplant, particularly for PTx recipients (group, P= 7.4×10 -7 , time, P =4.8×10 -6 , group*time, P= 1.2×10 -7 ). Procedure-related complications and hospital readmissions were higher after PTx ( P =2.5×10 -32 and P= 6.4×10 -112 , respectively). CONCLUSIONS: PTx shows higher sex-adjusted and age-adjusted mortality, procedure-related complications and readmissions compared with ITx. Conversely, insulin independence, graft survival and glycemic control are better with PTx. This study provides data to balance risks and benefits with ITx and PTx, which could improve shared decision-making.

Model of Acute Liver Failure in an Isolated Perfused Porcine Liver-Challenges and Lessons Learned.

Acute liver failure (ALF) is a rare but devastating disease associated with substantial morbidity and a mortality rate of almost 45%. Medical treatments, apart from supportive care, are limited and liver transplantation may be the only rescue option. Large animal models, which most closely represent human disease, can be logistically and technically cumbersome, expensive and pose ethical challenges. The development of isolated organ perfusion technologies, originally intended for preservation before transplantation, offers a new platform for experimental models of liver disease, such as ALF. In this study, female domestic swine underwent hepatectomy, followed by perfusion of the isolated liver on a normothermic machine perfusion device. Five control livers were perfused for 24 h at 37 °C, while receiving supplemental oxygen and nutrition. Six livers received toxic doses of acetaminophen given over 12 h, titrated to methemoglobin levels. Perfusate was sampled every 4 h for measurement of biochemical markers of injury (e.g., aspartate aminotransferase [AST], alanine aminotransferase [ALT]). Liver biopsies were taken at the beginning, middle, and end of perfusion for histological assessment. Acetaminophen-treated livers received a median dose of 8.93 g (8.21-9.75 g) of acetaminophen, achieving a peak acetaminophen level of 3780 µmol/L (3189-3913 µmol/L). Peak values of ALT (76 vs. 105 U/L; p = 0.429) and AST (3576 vs. 4712 U/L; p = 0.429) were not significantly different between groups. However, by the end of perfusion, histology scores were significantly worse in the acetaminophen treated group (p = 0.016). All acetaminophen treated livers developed significant methemoglobinemia, with a peak methemoglobin level of 19.3%, compared to 2.0% for control livers (p = 0.004). The development of a model of ALF in the ex vivo setting was confounded by the development of toxic methemoglobinemia. Further attempts using alternative agents or dosing strategies may be warranted to explore this setting as a model of liver disease.

Preclinical systematic review & meta-analysis of cyclosporine for the treatment of myocardial ischemia-reperfusion injury.

Background: Though best known for its immunosuppressant effects, cyclosporine A (CsA) has also been studied as a treatment to mitigate ischemia-reperfusion injury (IRI) by its inhibition of the mitochondria permeability transition pore (mPTP). Despite numerous preclinical studies supporting its benefit in reducing infarct size following myocardial IRI, large randomized controlled clinical trials have been unable to show a beneficial effect. Exploring existing preclinical data can give us the opportunity to revisit some the assumptions that may have led to the failure of these studies to translate clinically. Herein, we present a systematic review of preclinical studies testing CsA to attenuate myocardial IRI (PROSPERO CRD42020159620). Methods: We conducted a systematic search of health research databases Ovid MEDLINE, Ovid EMBASE, Web of Science BIOSIS, and Scopus, as well as Cochrane and PROSPERO systematic review databases, on March 9, 2022 for non-human in vivo animal studies of myocardial IRI, using CsA as a treatment that reported clinically relevant outcomes. Bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation's risk of bias tool and a modified Collaborative Approach to Meta Analysis and Review of Animal Data from Experimental Studies checklist. Sub-group meta-analyses were conducted to identify potential factors influencing outcomes. Results: We identified 71 studies, 59 of which were studies of coronary occlusion. Overall, 75% of studies reported a clear positive effect of CsA in mitigating myocardial IRI by some clinically relevant parameter (e.g., infarct size). A meta-analysis including 43 coronary occlusion studies showed an overall reduction in infarct size with CsA treatment (16.09%; 95% CI: -18.50% to -13.67%). Subgroup meta-analyses identified species, age, timing of administration, and duration of ischemia as factors potentially affecting the efficacy of CsA in the setting of myocardial IRI. Conclusions: Our systematic review and meta-analysis identifies questions that have yet to be answered by preclinical studies, highlighting important differences between these and clinical studies that should be addressed prior to proceeding with any further clinical studies using CsA to treat IRI in the heart or other organs. We also use the example of CsA to highlight general considerations for researchers attempting to translate animal studies into the clinical setting.

Pancreatic islet transplantation in type 1 diabetes: 20-year experience from a single-centre cohort in Canada.

BACKGROUND: Islet transplantation offers an effective treatment for selected people with type 1 diabetes and intractable hypoglycaemia. Long-term experience, however, remains limited. We report outcomes from a single-centre cohort up to 20 years after islet transplantation. METHODS: This cohort study included patients older than 18 years with type 1 diabetes undergoing allogeneic islet transplantation between March 11, 1999, and Oct 1, 2019, at the University of Alberta Hospital (Edmonton, AB, Canada). Patients who underwent islet-after-kidney transplantation and islet transplantation alone or islet transplantation before whole-pancreas transplantation (follow-up was censored at the time of whole-pancreas transplantation) were included. Patient survival, graft survival (fasting plasma C-peptide >0·1 nmol/L), insulin independence, glycaemic control, and adverse events are reported. To identify factors associated with prolonged graft survival, recipients with sustained graft survival (≥90% of patient follow-up duration) were compared with those who had non-sustained graft survival (<90% of follow-up duration). Multivariate binary logistic regression analyses were done to determine predictors of sustained graft survival. FINDINGS: Between March 11, 1999, and Oct 1, 2019, 255 patients underwent islet transplantation and were included in the analyses (149 [58%] were female and 218 [85%] were White). Over a median follow-up of 7·4 years (IQR 4·4-12·2), 230 (90%) patients survived. Median graft survival was 5·9 years (IQR 3·0-9·5), and graft failure occurred in 91 (36%) patients. 178 (70%) recipients had sustained graft survival, and 77 (30%) had non-sustained graft survival. At baseline, compared with patients with non-sustained graft survival, those with sustained graft survival had longer median type 1 diabetes duration (33·5 years [IQR 24·3-41·7] vs 26·2 years [17·0-35·5]; p=0·0003), median older age (49·4 years [43·5-56·1] vs 44·2 years [35·4-54·2]; p=0·0011), and lower median insulin requirements (0·53 units/kg per day [0·45-0·67] vs 0·59 units/kg per day [0·48-0·70]; p=0·032), but median HbA1c concentrations were similar (8·2% [7·5-9·0] vs 8·5% [7·8-9·2]; p=0·23). 201 (79%) recipients had insulin independence, with a Kaplan-Meier estimate of 61% (95% CI 54-67) at 1 year, 32% (25-39) at 5 years, 20% (14-27) at 10 years, 11% (6-18) at 15 years, and 8% (2-17) at 20 years. Patients with sustained graft survival had significantly higher rates of insulin independence (160 [90%] of 178 vs 41 [53%] of 77; p<0·0001) and sustained improvements in glycaemic control mixed-main-effects model group effect, p<0·0001) compared with those with non-sustained graft survival. Multivariate analyses identified the combined use of anakinra plus etanercept (adjusted odds ratio 7·5 [95% CI 2·7-21·0], p<0·0001) and the BETA-2 score of 15 or higher (4·1 [1·5-11·4], p=0·0066) as factors associated with sustained graft survival. In recipients with sustained graft survival, the incidence of procedural complications was lower (23 [5%] of 443 infusions vs 17 [10%] of 167 infusions; p=0·027), whereas the incidence of cancer was higher (29 of [16%] of 178 vs four [5%] of 77; p=0·015) than in those with non-sustained graft survival; most were skin cancers (22 [67%] of 33). End-stage renal disease and severe infections were similar between groups. INTERPRETATION: We present the largest single-centre cohort study of long-term outcomes following islet transplantation. Although some limitations with our study remain, such as the retrospective component, a relatively small sample size, and the absence of non-transplant controls, we found that the combined use of anakinra plus etanercept and the BETA-2 score were associated with improved outcomes, and therefore these factors could inform clinical practice. FUNDING: None.

Inflammation and Oxidative Stress in the Context of Extracorporeal Cardiac and Pulmonary Support.

Extracorporeal circulation (ECC) systems, including cardiopulmonary bypass, and extracorporeal membrane oxygenation have been an irreplaceable part of the cardiothoracic surgeries, and treatment of critically ill patients with respiratory and/or cardiac failure for more than half a century. During the recent decades, the concept of extracorporeal circulation has been extended to isolated machine perfusion of the donor organ including thoracic organs (ex-situ organ perfusion, ESOP) as a method for dynamic, semi-physiologic preservation, and potential improvement of the donor organs. The extracorporeal life support systems (ECLS) have been lifesaving and facilitating complex cardiothoracic surgeries, and the ESOP technology has the potential to increase the number of the transplantable donor organs, and to improve the outcomes of transplantation. However, these artificial circulation systems in general have been associated with activation of the inflammatory and oxidative stress responses in patients and/or in the exposed tissues and organs. The activation of these responses can negatively affect patient outcomes in ECLS, and may as well jeopardize the reliability of the organ viability assessment, and the outcomes of thoracic organ preservation and transplantation in ESOP. Both ECLS and ESOP consist of artificial circuit materials and components, which play a key role in the induction of these responses. However, while ECLS can lead to systemic inflammatory and oxidative stress responses negatively affecting various organs/systems of the body, in ESOP, the absence of the organs that play an important role in oxidant scavenging/antioxidative replenishment of the body, such as liver, may make the perfused organ more susceptible to inflammation and oxidative stress during extracorporeal circulation. In the present manuscript, we will review the activation of the inflammatory and oxidative stress responses during ECLP and ESOP, mechanisms involved, clinical implications, and the interventions for attenuating these responses in ECC.

Tumor necrosis factor receptor superfamily member 25 (TNFRSF25) agonists in islet transplantation: Endogenous in vivo regulatory T cell expansion promotes prolonged allograft survival.

Regulatory T cells (Tregs) modulate alloimmune responses and may facilitate minimization or withdrawal of immunosuppression posttransplant. Current approaches, however, rely on complex ex vivo Treg expansion protocols. Herein, we explore endogenous in vivo Treg expansion through antibody-mediated agonistic stimulation of the tumor necrosis factor receptor superfamily member 25 (TNFRSF25) pathway and its potential to prolong graft survival in a mouse model of islet allotransplantation. C57BL/6 male mice were treated with a single dose of TNFRSF25 agonistic antibodies (4C12 or mPTX-35) or IgG control. Diabetes was induced using streptozotocin. Four days later, flow cytometry was completed to corroborate Treg expansion, and 500 islets (CBA/J male mice) were transplanted. Glycemia was assessed thrice weekly until rejection/endpoint. Early intra-graft Treg infiltration was assessed 36 h posttransplant. TNFRSF25 antibodies enabled pronounced Treg expansion and treated mice had significantly prolonged graft survival compared with controls (p < .001). Additionally, the degree of Treg expansion significantly correlated with graft survival (p < .001). Immunohistochemistry demonstrated marked Treg infiltration in long-term surviving grafts; intra-graft Treg infiltration occurred early posttransplant. In conclusion, a single dose of TNFRSF25 antibodies enabled in vivo Treg expansion, which promotes prolonged graft survival. TNFRSF25-mediated in vivo Treg expansion could contribute to achieving lasting immunological tolerance in organ transplantation.

Preclinical models of acute liver failure: a comprehensive review.

Acute liver failure is marked by the rapid deterioration of liver function in a previously well patient over period of days to weeks. Though relatively rare, it is associated with high morbidity and mortality. This makes it a challenging disease to study clinically, necessitating reliance on preclinical models as means to explore pathophysiology and novel therapies. Preclinical models of acute liver failure are artificial by nature, and generally fall into one of three categories: surgical, pharmacologic or immunogenic. This article reviews preclinical models of acute liver failure and considers their relevance in modeling clinical disease.

Total pancreatectomy with islet cell autotransplantation in a 2-year-old child with hereditary pancreatitis due to a PRSS1 mutation.

Acute recurrent and chronic pancreatitis in children carries high morbidity and burden. Compared to adults, ~75% of the cases of chronic pancreatitis in children are associated with underlying genetic mutations. The decision to intervene and the optimal timing poses unique challenges. Total pancreatectomy and islet cell autotransplantation (TPIAT) provides definitive therapy to relieve pain and improve quality of life while minimizing the risk of pancreatogenic diabetes. Substantial clinical data are available for adults; however, information on clinical outcomes in children remains scarce, particularly for very young children. Herein, we present an unusual, complex case of a 2-year-old child that underwent a successful TPIAT due to hereditary pancreatitis with an underlying mutation in PRSS1 gene, complicated by unremitting pancreatic ascites, hemorrhage, and sepsis. This is the youngest case to be reported in the literature. We provide a comprehensive report of the course and procedures implemented in this patient to guide other teams when considering these extraordinary measures in similar cases.

Progress in Translational Regulatory T Cell Therapies for Type 1 Diabetes and Islet Transplantation.

Regulatory T cells (Tregs) have become highly relevant in the pathophysiology and treatment of autoimmune diseases, such as type 1 diabetes (T1D). As these cells are known to be defective in T1D, recent efforts have explored ex vivo and in vivo Treg expansion and enhancement as a means for restoring self-tolerance in this disease. Given their capacity to also modulate alloimmune responses, studies using Treg-based therapies have recently been undertaken in transplantation. Islet transplantation provides a unique opportunity to study the critical immunological crossroads between auto- and alloimmunity. This procedure has advanced greatly in recent years, and reports of complete abrogation of severe hypoglycemia and long-term insulin independence have become increasingly reported. It is clear that cellular transplantation has the potential to be a true cure in T1D, provided the remaining barriers of cell supply and abrogated need for immune suppression can be overcome. However, the role that Tregs play in islet transplantation remains to be defined. Herein, we synthesize the progress and current state of Treg-based therapies in T1D and islet transplantation. We provide an extensive, but concise, background to understand the physiology and function of these cells and discuss the clinical evidence supporting potency and potential Treg-based therapies in the context of T1D and islet transplantation. Finally, we discuss some areas of opportunity and potential research avenues to guide effective future clinical application. This review provides a basic framework of knowledge for clinicians and researchers involved in the care of patients with T1D and islet transplantation.

Machine Perfusion of the Liver: Applications Beyond Transplantation.

Machine perfusion (MP) is at the forefront of innovation in modern liver transplantation. Several approaches, mainly varying the temperature at which the graft is perfused, have shown benefit in preclinical models and nonrandomized clinical trials. Given the recent randomized controlled trial by Nasralla et al demonstrating the efficacy of normothermic MP over static cold storage, MP is likely here to stay for the foreseeable future. We are only beginning to explore the possibilities of this technology, including the prediction of graft function and modification of suboptimal livers. This has the potential to both increase the donor pool and improve the quality of grafts provided to recipients. Beyond transplantation, there may be a role for MP in extracorporeal liver support, cancer research and therapeutics, and pharmaceutical testing. In this review, we provide the rationale and explore the relevant preclinical studies that support the use of ex situ liver perfusion for these extended applications.

Pan-caspase inhibitor F573 mitigates liver ischemia reperfusion injury in a murine model.

BACKGROUND: Liver ischemia reperfusion injury (IRI) remains a challenge in liver transplantation. A number of compounds have previously demonstrated efficacy in mitigating IRI. Herein, we applied three specific additive strategies to a mouse IRI screening model to determine their relative potencies in reducing such injury, with a view to future testing in a large animal and clinical ex situ normothermic perfusion setting: 1) F573, a pan-caspase inhibitor, 2) anti-inflammatory anakinra and etanrecept and 3) BMX-001, a mimetic of superoxide dismutase. METHODS: A non-lethal liver ischemia model in mice was used. Additives in the treatment groups were given at fixed time points before induction of injury, compared to a vehicle group that received no therapeutic treatment. Mice were recovered for 6 hours following the ischemic insult, at which point blood and tissue samples were obtained. Plasma was processed for transaminase levels. Whole liver tissue samples were processed for histology, markers of apoptosis, oxidative stress, and cytokine levels. RESULTS: In an in vivo murine IRI model, the F573 treatment group demonstrated statistically lower alanine aminotransferase (ALT) levels (p = 0.01), less evidence of apoptosis (p = 0.03), and lower cytokine levels compared to vehicle. The etanercept with anakinra treatment group demonstrated significantly lower cytokine levels. The BMX-001 group demonstrated significantly decreased apoptosis (p = 0.01) evident on TUNEL staining. CONCLUSIONS: The administration of pan-caspase inhibitor F573 in a murine in vivo model likely mitigates liver IRI based on decreased markers of cellular injury, decreased evidence of apoptosis, and improved cytokine profiles. Anakinra with etanercept, and BMX-001 did not demonstrate convincing efficacy at reducing IRI in this model, and likely need further optimization. The positive findings set rational groundwork for future translational studies of applying F573 during normothermic ex situ liver perfusion, with the aim of improving the quality of marginal grafts.

Concurrent bariatric surgery and paraesophageal hernia repair: an analysis of the Metabolic and Bariatric Surgery Association Quality Improvement Program (MBSAQIP) database.

BACKGROUND: Paraesophageal hernias (PEH) are common among patients with obesity. Most patients with severe obesity and a PEH will have the PEH repaired at the time of bariatric surgery. However, it is unclear whether there is increased risk when repairing a PEH during bariatric surgery. OBJECTIVES: To examine short-term outcomes of patients undergoing bariatric surgery with concurrent PEH repair versus bariatric surgery alone. SETTING: Accredited bariatric centers across the United States and Canada. METHODS: Patients who underwent bariatric surgery with concurrent PEH repair were identified from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry. Using a propensity-score matching algorithm, these patients were matched with a cohort who underwent bariatric surgery only, controlling for age, sex, and other co-morbidities. Overall, 30-day incidence of major complications was the primary outcome. Secondary outcomes included mortality, length of operation, reoperations, and readmissions. RESULTS: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database identified 222,320 bariatric procedures without PEH and 42,732 procedures with concurrent PEH repair. With one-to-one propensity score matching, 42,379 pairs were selected. Background characteristics, including age, sex, preoperative body mass index, and preoperative co-morbidities, did not differ statistically between matched cohorts. There was no statistically significant difference in 30-day major complications (3.5% versus 3.4%, P = .317). CONCLUSIONS: Our analysis indicates that the incidence of major complications for bariatric surgery with concurrent PEH repair is similar to bariatric surgery alone. Overall, this study demonstrates the safety of concurrent bariatric surgery and PEH repair.

Bariatric Surgery Outcomes in Patients on Preoperative Therapeutic Anticoagulation: an Analysis of the 2015 to 2017 MBSAQIP.

BACKGROUND: Obesity has been found to be an independent predictor of adverse cardiac and pulmonary embolic events. As the popularity of bariatric surgery grows, surgeons are encountering more patients taking therapeutic anticoagulation medications preoperatively. This study aims to assess the safety of bariatric surgery on these patients. METHODS: Data was extracted from 2015 to 2017 using the MBSAQIP database. Included patients were those who underwent a primary LSG or LRYGB. A multivariable regression analysis was performed looking at 30-day outcomes for pre-operatively anticoagulated patients. A secondary propensity-matched analysis was performed comparing outcomes among patients undergoing LSG vs LRYGB. RESULTS: A total of 430,396 patients were analyzed, 11,013 (2.56%) of which were taking anticoagulation medications pre-operatively. Absolute 30-day complication rates (8.73% vs 3.36%, p < 0.001), bleed rates (3.78% vs 0.88%, p < 0.001), leak rates (0.55% vs 0.41%, p = 0.021), cardiac event rates (0.43% vs 0.06%, p < 0.001), and venous thromboembolism rates (0.68% vs 0.25%, p < 0.001) were significantly higher among pre-operatively anticoagulated patients. On multivariable analysis, pre-operative anticoagulation was found to be an independent predictor of postoperative bleeding (OR 2.76, CI 2.43-3.14, p < 0.001) and mortality (OR 2.08, CI 1.49-2.90, p < 0.001). The LRYGB was associated with a significantly higher complication rate compared to the LSG (13.27% vs 7.40%, p < 0.001) in the propensity-matched cohorts. CONCLUSIONS: Patients undergoing bariatric surgery on anticoagulation medications pre-operatively are at a significantly higher risk of adverse outcomes post-operatively. Patients who require long-term anticoagulation should undergo careful consideration before proceeding with bariatric surgery.

Effects of Chronic Corticosteroid and Immunosuppressant Use in Patients Undergoing Bariatric Surgery.

BACKGROUND: Chronic immunosuppression can put surgical patients at additional risk for complications, particularly infection. This is not a contraindication for patients undergoing bariatric surgery. However, with the increasing prevalence of bariatric surgery, it is important to characterize the additional risks for immunosuppressed patients. METHODS: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) data registry was used to identify immunosuppressed patients who had undergone bariatric surgery. Patients undergoing primary bariatric surgery (laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy) at an accredited institution between 2015 and 2017 were included. A multivariable regression analysis was performed, controlling for age, sex, procedure, and several other comorbidities. Overall 30-day incidence of major complications was the primary outcome. A secondary analysis compared outcomes amongst immunosuppressed patients by procedure type using a propensity-matched analysis. Propensity matching was performed based on preoperative comorbidities and bariatric procedure. RESULTS: A total of 430,936 patients were included in the study. Of these, 7214 (1.7%) were chronically immunosuppressed. Our multivariable regression analysis found statistically higher odds of 30-day major complications (OR 1.39, 95% CI 1.25-1.55; p < 0.001), bleed (OR 1.49, 95% CI 1.24-1.80; p < 0.001) and anastomotic leak (OR 1.38, 95% CI 1.02-1.87; p = 0.037) amongst immunosuppressed patients. However, there was no difference between 30-day mortality (OR 1.15, 95% CI 0.64-2.07; p = 0.644). Our secondary analysis found higher rates of 30-day major complications for immunosuppressed patients undergoing gastric bypass (9.6% vs. 5.0%; p < 0.001). CONCLUSION: Immunosuppressed patients are at higher risk of major complications when undergoing bariatric surgery, especially gastric bypass.

Radioactive Seed Localization Versus Wire-Guided Localization for Nonpalpable Breast Cancer: A Cost and Operating Room Efficiency Analysis.

BACKGROUND: This study aimed to compare the cost and resource use between our first-year experience using breast-conserving surgery (BCS) with radioactive seed localization (RSL) and the previous-year standard practice of BCS with wire-guided localization (WGL) for patients with nonpalpable breast cancer at a large Canadian tertiary center. METHODS: For this retrospective cohort study, data for BCS cases with RSL was collected from 1 April 2015 to 31 March 2016 and for BCS cases with WGL from 1 April 2014 to 31 March 2015. RESULTS: The study compared 153 WGL patients with 194 RSL patients. The two groups had no significant demographic differences. The average cost per patient for RSL, including opportunity costs, was $250.90 versus $1130.41 for WGL. Dedicated allocated radiology appointments to RSL increased (9 per day), and fewer radiologists were required for these procedures per day. Patients were transported to the operating room more quickly for RSL procedures (120 vs. 254 min; p < 0.001). Fewer vasovagal reactions occurred after insertion of RSL versus WGL (p = 0.05). No significant differences were observed in terms of surgical time, specimen volume, positive margins, or margin reexcision rates. No significant differences in postoperative complication rates were observed. CONCLUSIONS: In this study, RSL had lower costs than WGL, allowed for more efficient use of radiology scheduling and resources, and had shorter wait times for patients on their day of surgery. In addition, RSL led to fewer vasovagal reactions at insertion. Therefore, RSL should be used instead of WGL given the reduced cost, decreased need of human resources, improved efficiency, and potential benefits to the patient experience.

Can CanMEDS competencies be developed in medical school anatomy laboratories? A literature review.

OBJECTIVES: The purpose of this literature review was to identify potential ways in which undergraduate medical anatomy education may be relevant to the CanMEDS Roles, a competency-based framework used throughout Canadian medical training. METHODS: A scoping review of medical education literature was conducted in March 2017 for English language publications that included key words related to anatomy education and to key competencies formally described for each of the Roles in the CanMEDS 2015 framework. Indicated benefits were then collated, characterized, and synthesized for each CanMEDS Role. RESULTS: There were 71 studies identified describing original findings. Perceived benefits of anatomy education were most often identified for competencies related to the Medical Expert Role. Multiple studies also cited benefits related to the Scholar, Professional and Collaborator Roles. There was a lack of literature related to the Health Advocate, Communicator, and Leader Roles. The majority of benefits defined in the literature were limited to student perceptions rather than objectively measured outcomes. CONCLUSIONS: There is some evidence to suggest that anatomy education can facilitate the development of core competencies related to several CanMEDS Roles, outside of simply developing medical knowledge in the Medical Expert Role. Future studies need to develop methods to objectively assess outcomes related to these competencies.

Transcriptional Activation of p53 during Cold Induced Torpor in the 13-Lined Ground Squirrel Ictidomys tridecemlineatus.

The transcription factor p53 is located at the centre of multiple pathways relating the cellular response to stress. Commonly known as a tumor suppressor, it is responsible for initiating diverse actions to protect the integrity of the genome, ranging from cell cycle arrest to apoptosis. This study investigated the regulation of p53 protein in hibernating 13-lined ground squirrel Ictidomys tridecemlineatus during multiple stages of the torpor-arousal cycle. Transcript and protein levels of p53 were both elevated in the skeletal muscle during early and late torpor stages of the hibernation cycle. Nuclear localization of p53 was also increased during late torpor, and this is associated with an increase in its DNA binding activity and expression of p53 transcriptional targets p21CIP, gadd45α, and 14-3-3σ. The increase in p53 transcriptional activity appears to be independent of its phosphorylation at Ser-15, Ser-46, and Ser-392, consistent with an absence of checkpoint kinase activation during torpor. Sequence analysis revealed unique amino acid substitutions in the ground squirrel p53 protein, which may contribute to an increase in protein stability compared to nonhibernators. Overall, the study results provided evidences for a potential role of p53 in the protection of the skeletal muscle during torpor.