Tailoring the Use of Central Pancreatectomy Through Prediction Models for Major Morbidity and Postoperative Diabetes: International Retrospective Multicenter Study.

OBJECTIVE: To develop a prediction model for major morbidity and endocrine dysfunction after CP which could help in tailoring the use of this procedure. SUMMARY BACKGROUND DATA: Central pancreatectomy (CP) is a parenchyma-sparing alternative to distal pancreatectomy for symptomatic benign and pre-malignant tumors in body and neck of the pancreas CP lowers the risk of new-onset diabetes and exocrine pancreatic insufficiency compared to distal pancreatectomy but it is thought to increase the risk of short-term complications including postoperative pancreatic fistula (POPF). METHODS: International multicenter retrospective cohort study including patients from 51 centers in 19 countries (2010-2021). Primary endpoint was major morbidity. Secondary endpoints included POPF grade B/C, endocrine dysfunction, and the use of pancreatic enzymes. Two risk model were designed for major morbidity and endocrine dysfunction utilizing multivariable logistic regression and internal and external validation. RESULTS: 838 patients after CP were included (301 (36%) minimally invasive) and major morbidity occurred in 248 (30%) patients, POPF B/C in 365 (44%), and 30-day mortality in 4 (1%). Endocrine dysfunction in 91 patients (11%) and use of pancreatic enzymes in 108 (12%). The risk model for major morbidity included male sex, age, BMI, and ASA score≥3. The model performed acceptable with an area under curve (AUC) of 0.72(CI:0.68-0.76). The risk model for endocrine dysfunction included higher BMI and male sex and performed well (AUC:0.83 (CI:0.77-0.89)). CONCLUSIONS: The proposed risk models help in tailoring the use of CP in patients with symptomatic benign and premalignant lesions in the body and neck of the pancreas and are readily available via www.pancreascalculator.com.

Impact of liver failure on the circulating extracellular vesicle miRNA repertoire.

BACKGROUND & AIMS: Cell-derived small extracellular vesicles (sEVs) participate in cell-cell communication via the transfer of molecular cargo including selectively enriched microRNAs (miRNAs). Utilizing advances in sEV isolation and characterization, this study investigates the impact of liver injury and dysfunction on the circulating EV-miRNA profile. METHODS: High-throughput screening of 799 sEV-miRNAs isolated from plasma was performed in patients across a spectrum of liver disorders including compensated and decompensated chronic liver disease, acute-on-chronic liver failure (ACLF), and acute liver failure, in addition to healthy controls and those with severe sepsis. miRNA levels were compared with clinical and biochemical parameters, composite scores of liver disease, and patient outcomes. RESULTS: miRNA screening revealed the degree of hepatic dysfunction to be the main determinant of changes in circulating sEV-miRNA profile, with liver-specific miRNA-122 being among the most highly dysregulated in severe injury. Principal components analyses of the 215 differentially expressed miRNAs showed differing profiles, particularly among those with acute liver injury and ACLF. A distinct profile of dysregulated miRNA, but not circulating cytokines, was shown to characterize ACLF, with four consensus miRNAs identified-miR-320e, miR-374-5p, miR-202-3p, and miR-1910-5p. High miR-320e was associated with poorer 90-day survival (p = 0.014) and regulated the functional gene targets IK, RPS5, MANBAL, and PEBP1. CONCLUSIONS: This first comprehensive analysis to the best of our knowledge of patients with varying degrees and stages of liver failure demonstrates miRNA profiles specifically within the sEV compartment to be significantly altered in progressive liver disease and highlights the diagnostic and prognostic potential of sEV-miRNA in ACLF while also establishing downstream gene targets.

Prophylactic administration of alpha-blockers for the prevention of post-operative urinary retention following inguinal hernia repair: A meta-analysis of randomized control trials.

BACKGROUND: Inguinal hernia repair is a commonly performed surgical procedure performed in adult males. Urinary retention following surgery is a known complication likely due to the adrenergic over-stimulation of smooth muscles in the bladder neck and prostate. This effect could potentially be mitigated by the use of alpha-blocker medications. A meta-analysis of randomized control trials (RCTs) was performed to analyse the evidence behind the use of alpha-blockers in the prevention of post-operative urinary retention (POUR). METHODS: A comprehensive search of PubMed, Embase, MedLine and Scopus was undertaken adhering to PRISMA guidelines. RCTs using alpha-blockers as a single point intervention were included. Data were analysed using a random-effects model. Risk of Bias (ROB) was assessed according to Cochrane guidelines. RESULTS: Seven RCTs including 680 patients were included. The use of alpha-blockade reduced the incidence of urinary retention requiring catheterization (OR:0.23, 95% CI:0.07-0.70, p:0.009). No serious side-effects of alpha-blockers were reported. CONCLUSION: Alpha-blockers are a safe and effective intervention to reduce the incidence of urinary retention following inguinal hernia repair surgery.

IL-2 availability regulates the tissue specific phenotype of murine intra-hepatic Tregs.

CD4+CD25+Foxp3+ Tregs are known to acquire tissue-specific features and exert cytoprotective and regenerative functions. The extent to which this applies to liver-resident Tregs is unknown. In this study, we aimed to explore the phenotypic and functional characteristics of adult murine liver resident Tregs during homeostasis. Additionally, we investigated their role in ameliorating liver inflammation and tissue damage. Quantification of Foxp3+CD4+CD25+ cells comparing different tissues showed that the liver contained significantly fewer resident Tregs. A combination of flow cytometry phenotyping and microarray analysis of intra-hepatic and splenic Tregs under homeostatic conditions revealed that, although intra-hepatic Tregs exhibited the core transcriptional Treg signature, they expressed a distinct transcriptional profile. This was characterized by reduced CD25 expression and increased levels of pro-inflammatory Th1 transcripts Il1b and Ifng. In vivo ablation of Tregs in the Foxp3-DTR mouse model showed that Tregs had a role in reducing the magnitude of systemic and intra-hepatic inflammatory responses following acute carbon tetrachloride (CCl4) injury, but their absence did not impact the development of hepatocyte necrosis. Conversely, the specific expansion of Tregs by administration of IL-2 complexes increased the number of intra-hepatic Tregs and significantly ameliorated tissue damage following CCl4 administration in C57BL/6 mice. The cytoprotective effect observed in response to IL-2c was associated with the increased expression of markers known to regulate Treg suppressive function. Our results offer insight into the transcriptome and complex immune network of intra-hepatic Tregs and suggest that strategies capable of selectively increasing the pool of intra-hepatic Tregs could constitute effective therapies in inflammatory liver diseases.

Visceral-to-subcutaneous fat ratio exhibits strongest association with early post-operative outcomes in patients undergoing surgery for advanced rectal cancer.

AIM: Despite their promise as prognostic factors in colorectal cancer, anthropometric data are frequently contradictory or difficult to interpret, with single body-composition parameters often investigated in isolation or heterogeneous clinical cohorts used in analyses. We sought to assess a spectrum of body-composition parameters in a highly selected cohort with locally advanced rectal cancer in a bid to determine those with strongest prognostic potential in this specific setting. MATERIALS/METHODS: Between 2014 and 2020, 78 individuals received neoadjuvant chemotherapy, or chemoradiotherapy, followed by radical surgery in the treatment of locally advanced rectal adenocarcinoma at Oxford University Hospitals Trust. Demographic, treatment-related, perioperative, and short-term outcomes data were assessed. Body-composition parameters included BMI, and those derived from pre-operative computed-tomography imaging: skeletal mass index (SMI), visceral fat area (VFA), subcutaneous fat area (SFA), perinephric fat area (PFA) visceral-to-subcutaneous fat ratio (V/S), sarcopenia, and sarcopenic obesity (SO). RESULTS: Pre-operative body-composition parameters exhibited particularly strong correlation with post-operative outcomes, with VFA (p = 0.002), V/S (p = 0.019), SO (p = 0.012), and PFA (p = 0.0016) all associated with an increased length of hospital stay. Univariate and multivariate analyses demonstrated V/S to be the sole independent body-composition risk factor to be associated with an increased risk of developing Clavien-Dindo complications ≥ 2 (p = 0.033) as well as an increased length of stay (p = 0.005). CONCLUSION: Among patients with locally advanced rectal cancer, high visceral-to-subcutaneous fat ratio is the body-composition parameter most strongly associated with poor early post-operative outcomes. This should be considered in patient selection and prehabilitation protocols. WHAT DOES THIS PAPER ADD TO THE LITERATURE? : Our study demonstrates that among body composition parameters, high visceral-to-subcutaneous fat ratio is strongly associated with increased risk of post-operative complications and increased length of stay in patients undergoing surgery for advanced rectal cancer.

Endoscopic vacuum therapy (EVT) in the management of oesophageal perforations and post-operative leaks.

INTRODUCTION: Oesophageal perforations and post-oesophagectomy anastomotic leaks are associated with high morbidity and mortality. Endoscopic vacuum therapy (EVT) is a novel treatment strategy with the potential to promote healing and ameliorate sepsis. Only two cases of its use have been reported in the UK in the management of oesophageal wall defects, representing a limited aetiological and demographic spectrum. MATERIAL AND METHODS: From May to December 2019, 7 patients aged 27-85 years underwent EVT for disparate oesophageal wall defects. Data regarding technical success and feasibility were analysed. RESULTS: Complete defect resolution was achieved in six cases (86%), requiring median of 13 days of treatment (range 6-23), and necessitating three replacement procedures (range 1-4). Significant improvement in C-reactive protein was achieved in all patients undergoing treatment (p = .015). No severe complications occurred that resulted directly from sponge placement, however two individuals (33%) developed oesophageal stricture necessitating endoscopic balloon dilatation, and one died whilst undergoing treatment. CONCLUSION: In selected patients EVT is a safe, valuable tool for the management of a spectrum of oesophageal wall defects, with the potential to reduce associated morbidity and mortality. While this work significantly expands upon the UK reported experience of EVT, we outline the requirement for a national, prospective registry of EVT use in oesophageal leaks and perforations. ABBREVIATIONS: AL: anastomotic leak; CRP: C-reactive protein; CT: computed tomography; EVT: endoscopic vacuum therapy; HES: hospital episode statistics; OGD: oesophago-gastro-duodenoscopy; SEMS: oesophageal stenting with self-expanding stents; UK: United Kingdom.

Current Status of Endoscopic Vacuum Therapy in the Management of Esophageal Perforations and Post-Operative Leaks.

Esophageal wall defects, including perforations and postoperative leaks, are associated with high morbidity and mortality and pose a significant management challenge. In light of the high morbidity of surgical management or revision, in recent years, endoscopic vacuum therapy (EVT) has emerged as a novel alternative treatment strategy. EVT involves transoral endoscopic placement of a polyurethane sponge connected to an externalized nasogastric tube to provide continuous negative pressure with the intention of promoting defect healing, facilitating cavity drainage, and ameliorating sepsis. In the last decade, EVT has become increasingly adopted in the management of a diverse spectrum of esophageal defects. Its popularity has been attributed in part to the growing body of evidence suggesting superior outcomes and defect closure rates in excess of 80%. This growing body of evidence, coupled with the ongoing evolution of the technology and techniques of deployment, suggests that the utilization of EVT has become increasingly widespread. Here, we aimed to review the current status of the field, addressing the mechanism of action, indications, technique methodology, efficacy, safety, and practical considerations of EVT implementation. We also sought to highlight future directions for the use of EVT in esophageal wall defects.

Laparoscopic vs. open feeding jejunostomy insertion in oesophagogastric cancer.

BACKGROUND: Jejunal feeding is an invaluable method by which to improve the nutritional status of patients undergoing neoadjuvant and surgical treatment of oesophageal malignancies. However, the insertion of a feeding jejunostomy can cause significant postoperative morbidity. The aim of this study is to compare the outcomes of patients undergoing placement of feeding jejunostomy by conventional laparotomy with an alternative laparoscopic approach. METHODS: A retrospective review of data prospectively collected at the Oxford Oesophagogastric Centre between August 2017 and July 2019 was performed including consecutive patients undergoing feeding jejunostomy insertion. RESULTS: In the study period, 157 patients underwent jejunostomy insertion in the context of oesophageal cancer therapy, 126 (80%) by open technique and 31 (20%) laparoscopic. Pre-operative demographic and nutritional characteristics were broadly similar between groups. In the early postoperative period jejunostomy-associated complications were noted in 54 cases (34.4%) and were significantly more common among those undergoing open as compared with laparoscopic insertion (38.1% vs. 19.3%, P = 0.049). Furthermore, major complications were more common among those undergoing open insertion, whether as a stand-alone or at the time of staging laparoscopy (n = 11/71), as compared with insertion at the time of oesophagectomy (n = 3/86, P = 0.011). CONCLUSIONS: This report represents the largest to our knowledge single-centre comparison of open vs. laparoscopic jejunostomy insertion in patients undergoing oesophagectomy in the treatment of gastroesophageal malignancy. We conclude that the laparoscopic jejunostomy insertion technique described represents a safe and effective approach to enteral access which may offer superior outcomes to conventional open procedures.

Impact of donor extracellular vesicle release on recipient cell "cross-dressing" following clinical liver and kidney transplantation.

In several murine models of transplantation, the "cross-dressing" of recipient antigen presenting cells (APCs) with intact donor major histocompatibility complex (MHC) derived from allograft-released small extracellular vesicles (sEVs) has been recently described as a key mechanism in eliciting and sustaining alloimmune responses. Investigation of these processes in clinical organ transplantation has, however, been hampered by the lack of sensitivity of conventional instruments and assays. We have employed advanced imaging flow cytometry (iFCM) to explore the kinetics of allograft sEV release and the extent to which donor sEVs might induce cross-dressing following liver and kidney transplantation. We report for the first time that recipient APC cross-dressing can be transiently detected in the circulation shortly after liver, but not kidney, transplantation in association with the release of HLA-bearing allograft-derived sEVs. In liver transplant recipients the majority of circulating cells exhibiting donor HLA are indeed cross-dressed cells and not passenger leukocytes. In keeping with experimental animal data, the downstream functional consequences of the transfer of circulating sEVs harvested from human transplant recipients varies depending on the type of transplant and time posttransplant. sEVs released shortly after liver, but not kidney, transplantation exhibit immunoinhibitory effects that could influence liver allograft immunogenicity.

Extracellular vesicles as mediators of alloimmunity and their therapeutic potential in liver transplantation.

Extracellular vesicles (EVs) are a heterogenous group of nanosized, membrane-bound particles which are released by most cell types. They are known to play an essential role in cellular communication by way of their varied cargo which includes selectively enriched proteins, lipids, and nucleic acids. In the last two decades, wide-ranging evidence has established the involvement of EVs in the regulation of immunity, with EVs released by immune and non-immune cells shown to be capable of mediating immune stimulation or suppression and to drive inflammatory, autoimmune, and infectious disease pathology. More recently, studies have demonstrated the involvement of allograft-derived EVs in alloimmune responses following transplantation, with EVs shown to be capable of eliciting allograft rejection as well as promoting tolerance. These insights are necessitating the reassessment of standard paradigms of T cell alloimmunity. In this article, we explore the latest understanding of the impact of EVs on alloresponses following transplantation and we highlight the recent technological advances which have enabled the study of EVs in clinical transplantation. Furthermore, we discuss the rapid progress afoot in the development of EVs as novel therapeutic vehicles in clinical transplantation with particular focus on liver transplantation.

Human iPS derived progenitors bioengineered into liver organoids using an inverted colloidal crystal poly (ethylene glycol) scaffold.

Generation of human organoids from induced pluripotent stem cells (iPSCs) offers exciting possibilities for developmental biology, disease modelling and cell therapy. Significant advances towards those goals have been hampered by dependence on animal derived matrices (e.g. Matrigel), immortalized cell lines and resultant structures that are difficult to control or scale. To address these challenges, we aimed to develop a fully defined liver organoid platform using inverted colloid crystal (ICC) whose 3-dimensional mechanical properties could be engineered to recapitulate the extracellular niche sensed by hepatic progenitors during human development. iPSC derived hepatic progenitors (IH) formed organoids most optimally in ICC scaffolds constructed with 140 µm diameter pores coated with type I collagen in a two-step process mimicking liver bud formation. The resultant organoids were closer to adult tissue, compared to 2D and 3D controls, with respect to morphology, gene expression, protein secretion, drug metabolism and viral infection and could integrate, vascularise and function following implantation into livers of immune-deficient mice. Preliminary interrogation of the underpinning mechanisms highlighted the importance of TGFß and hedgehog signalling pathways. The combination of functional relevance with tuneable mechanical properties leads us to propose this bioengineered platform to be ideally suited for a range of future mechanistic and clinical organoid related applications.

Multiparametric Analysis of Circulating Exosomes and Other Small Extracellular Vesicles by Advanced Imaging Flow Cytometry.

Extracellular vesicles (EVs) are responsible for a multitude of physiological functions, including immunomodulation. A heterogenous mixture of small EV (sEV) subsets, including putative exosomes, is derived when commonly used "exosome" isolation techniques are employed. Subset diversity relates in part to their different intracellular origins, and can be associated with distinct functional properties. Recent progress in the EV field has enabled the categorization of such subsets based on their surface composition. For the first time, we combine such emerging subset-specific markers with advanced imaging flow cytometry (iFCM) to perform high-throughput, multiparametric, vesicle-by-vesicle characterization, and functional assessment of specific small EV subsets, and exosomes in particular. The approach allows researchers to address three important applications. First, it is known that different isolation techniques result in the divergent recovery of particular vesicle subsets. Taking three commonly used "exosome" isolation techniques as test cases (ultracentrifugation, size-exclusion chromatography, and polymer-based precipitation), the capacity for convenient and accurate isolate compositional analysis by iFCM is demonstrated. The approach was able to corroborate and to quantify the known skewing of subtype recovery among different isolation approaches. Second, exosomes are a particularly widely studied EV subset. Applying exosome-specific markers to samples collected from an optimal clinical transplantation model, we verify the capacity for iFCM to detect exosomes in circulation, to establish their tissue of origin, and to provide insights as to their functional immunological potential. Finally, we describe a technique for establishing whether the transfer of a molecule of interest to a target cell is exosomally mediated. In so doing, we highlight the approach's utility in assessing the functional impact of circulating exosomes and in identifying their targets. In conclusion, we set out a new methodological approach by which small extracellular vesicle subsets, exosomes in particular, can be conveniently and comprehensively investigated, thereby offering novel phenotypic and functional insights.

IL-2 therapy restores regulatory T-cell dysfunction induced by calcineurin inhibitors.

CD4+CD25+FOXP3+ Tregs constitute a heterogeneous lymphocyte subpopulation essential for curtailing effector T cells and establishing peripheral tolerance. Calcineurin inhibitors (CNIs) are among the most effective agents in controlling effector T-cell responses in humans. However, CNIs also reduce the size of the Treg pool. The functional consequences of this negative effect and the mechanisms responsible remain to be elucidated. We report here that CNIs compromise the overall Treg immunoregulatory capacity to a greater extent than would be predicted by the reduction in the size of the Treg compartment, given that they selectively promote the apoptosis of the resting and activated Treg subsets that are known to display the most powerful suppressive function. These effects are caused by reduced access to IL-2, because Tregs remain capable of translocating NFAT even in the presence of high CNI levels. Exogenous IL-2 restores the phenotypic changes and overall gene-expression effects exerted by CNIs and can even promote Treg expansion by enhancing antiapoptotic Bcl-2 expression. In a skin transplant model, the addition of IL-2 synergizes with CNIs treatment, promoting intragraft accumulation of Tregs and prolonged allograft survival. Hence, the combination of IL-2 and CNIs constitutes an optimal immunomodulatory regimen that enhances the pool of suppressive Treg subsets while effectively controlling cytopathic T cells.

Biomarkers and immunopathology of tolerance.

PURPOSE OF REVIEW: This article describes biomarkers capable of identifying and predicting operational tolerance in solid organ transplant recipients. We outline the utility of these biomarkers in distinguishing allograft recipients in whom toxic immunosuppressive therapies might safely be minimized or withdrawn, and discuss their value in the appraisal of tolerance induction strategies. Finally, we review the insights derived from biomarker discovery into the cellular mechanisms underlying allograft tolerance. RECENT FINDINGS: Important progress has been made in the development of robust signatures of tolerance, in both renal and liver transplant settings. Methodological advances, including high-throughput sequencing and bioinformatic processes, have been brought to bear on biomarker discovery and have heralded improvements in the accuracy with which operational tolerance can be predicted. Although the immunopathological basis for donor-specific tolerance is increasingly recognized to involve a complex interplay between numerous cell types, we review new lines of evidence shedding light on these mechanisms. SUMMARY: Significant recent progress in identifying robust tolerance biomarkers has been made. In recognition of the need for rigorous validation of these, the first biomarker-led prospective immunosuppression withdrawal trials are underway. Such projects promise further progress and refinement in tolerance biomarker discovery, and offer hope for the amelioration of the burden associated with immunosuppressive therapies.

Emergent Transcriptomic Technologies and Their Role in the Discovery of Biomarkers of Liver Transplant Tolerance.

Liver transplantation offers a unique window into transplant immunology due, in part, to the considerable proportion of recipients who develop immunological tolerance to their allograft. Biomarkers are able to identify and predict such a state of tolerance, and thereby able to establish suitable candidates for the minimization of hazardous immunosuppressive therapies, are not only of great potential clinical benefit but might also shed light on the immunological mechanisms underlying tolerance and rejection. Here, we review the emergent transcriptomic technologies serving as drivers of biomarker discovery, we appraise efforts to identify a molecular signature of liver allograft tolerance, and we consider the implications of this work on the mechanistic understanding of immunological tolerance.

Novel biomarkers and functional assays to monitor cell-therapy-induced tolerance in organ transplantation.

PURPOSE OF REVIEW: Cell-based immunotherapy offers a novel approach to minimize the need for immunosuppressive drugs and to promote a state of immunological tolerance to a transplanted organ. We review the most promising biomarkers and functional assays able to identify patients tolerant to their graft. Such a signature of tolerance is essential in the assessment of the efficacy with which trials of cellular therapies promote immunoregulation and minimize graft rejection. RECENT FINDINGS: A multitude of novel cellular therapies have entered early-phase clinical trials in solid-organ transplant patients. Recent multicentre collaborations have enabled the determination of distinct tolerance profiles for both liver and kidney transplant recipients. These have been shown to be highly predictive of tolerance in certain settings and show utility in identifying patients in whom immunosuppressive drugs can be weaned or discontinued. SUMMARY: In order to become a viable treatment option in solid-organ transplantation, the latest large, multicentre clinical trials of cellular therapies must utilize, validate and discover the biomarkers with the capacity to reliably identify a signature of immune tolerance.

Safety of nephrectomy in morbidly obese donors.

OBJECTIVES: To satisfy donor organ shortage, overweight and obese donors are becoming a greater proportion of the kidney donor pool. Although good safety data exist in overweight and moderately obese individuals (body mass index = 25 to 35 kg/m²), there is little information about outcomes in morbidly obese donors (body mass index ≥ 40 kg/m²). The purpose of this study was to review the experience with morbidly obese donors in a single center and assist in the discussion about the feasibility of nephrectomy in such cases. MATERIALS AND METHODS: Outcomes of nephrectomy in morbidly obese donors between January 2005 and June 2010 were reviewed retrospectively and compared with outcomes in nonobese donors. RESULTS: Of 386 nephrectomies, 7 involved morbidly obese donors. Mortality and major complication rates were low in all body mass index categories. A high incidence of minor postoperative complications was observed in the morbidly obese, with 57% morbidly obese patients requiring treatment for complications including respiratory infection, compared with 30% in nonobese donors (P < .05). There were no significant differences in mean operative time, estimated blood loss, and length of hospital stay between all body mass index categories. Limited follow-up data (mean, 20 mo) showed similar renal function parameters between groups. CONCLUSIONS: The limited data suggest that nephrectomy may be feasible in selected morbidly obese donors. Further study is needed before major conclusions can be made.

Expanding the donor pool: living donor nephrectomy in the elderly and the overweight.

BACKGROUND: Increasing demand for donor kidneys, in parallel with trends toward more elderly and obese populations, make it important to continuously review donor pool inclusion criteria. Acceptance of elderly and obese living donors remains controversial, with a higher incidence of comorbidity and the greater risk of postoperative complications sighted as reasons for caution. Drawing on our center's experience, we aim to determine whether older age and obesity are in fact associated with greater perioperative risk, and longer term complications in donors undergoing nephrectomy. METHODS: Three hundred eighty-three living donor nephrectomies conducted at one of the United Kingdom's largest transplant units over the last 5 years were stratified into groups according to age and body mass index. Perioperative endpoints and postdonation follow-up data collected at 6-to-12-monthly intervals were analyzed and compared. RESULTS: No significant differences in operative parameters, including operative time and estimated blood loss, were reported between groups. Rates of early postoperative complications were not significantly different, although subgroup analysis showed a higher incidence of respiratory complications at the extremes of obesity (body mass index ≥ 40 kg/m²). On follow-up, renal function parameters showed significant change postnephrectomy, but between-group variation was not significant. Mortality and major complication rates were comparably low in all groups of study. CONCLUSIONS: In our unit's experience, nephrectomy in selected donors who may otherwise have been precluded from participation on account of their age or weight, is feasible and associated with perioperative and longer term outcomes comparable with their younger nonobese counterparts. It provides a basis for informed consent of "extended criteria" donors.