Immunomodulation of T cell-mediated Alloimmunity by Proximity to Endothelial Cells under mTOR Blockade.

Endothelial cells (ECs) are an initial barrier between vascularized organ allografts and the host immune system and are thus well positioned to initiate and influence alloimmune rejection. The mTOR inhibitor rapamycin is known to inhibit T cell activation and attenuate acute allograft rejection (AR). It also has numerous effects on ECs. We hypothesized that mTOR blockade might directly alter EC alloimmunogenicity and reduce alloimmune responses independent of its effects on T cell function. Here we report that rapamycin treatment modulates EC coinhibitory ligand expression and alters cytokine/chemokine production. It alters the EC transcriptome broadly associated with negative regulation of immune responses. Rapamycin-treated ECs suppress EC-specific T cell proliferation independent of PD1/PD ligand interactions, and inhibit T cells responding to adjacent allogeneic cells in a contact-independent manner via secreted inhibitory mediators above 10 kDa. The T cell hypo-responsiveness induced by rapamycin-pretreated ECs was rescued by exogenous IL-2. Pre-exposing donor hearts to rapamycin improves the effect of B7 costimulation blockade in prolonging heart allograft survival in an MHC-mismatched mouse model. Our results indicate that rapamycin treated ECs have reduced alloimmunogenicity and create a local, contact-independent environment that limits T cell alloreactivity via anergy induction and improves the efficacy of B7 costimulation blockade.

Post-kidney transplant body mass index trajectories are associated with graft loss and mortality.

BACKGROUND: Early post-kidney transplantation (KT) changes in physiology, medications, and health stressors likely impact body mass index (BMI) and likely impact all-cause graft loss and mortality. METHODS: We estimated 5-year post-KT (n = 151 170; SRTR) BMI trajectories using an adjusted mixed effects model. We estimated long-term mortality and graft loss risks by 1-year BMI change quartile (decrease [1st quartile]: change < -.07 kg/m2 /month; stable [2nd quartile]: -.07 ≤ change ≤ .09 kg/m2 /month; increase [3rd, 4th quartile]: change > .09 kg/m2 /month) using adjusted Cox proportional hazards models. RESULTS: BMI increased in the 3 years post-KT (.64 kg/m2 /year, 95% CI: .63, .64) and decreased in years 3-5 (-.24 kg/m2 /year, 95% CI: -.26, -.22). 1-year post-KT BMI decrease was associated with elevated risks of all-cause mortality (aHR = 1.13, 95% CI: 1.10-1.16), all-cause graft loss (aHR = 1.13, 95% CI: 1.10-1.15), death-censored graft loss (aHR = 1.15, 95% CI: 1.11-1.19), and mortality with functioning graft (aHR = 1.11, 95% CI: 1.08-1.14). Among recipients with obesity (pre-KT BMI≥30 kg/m2 ), BMI increase was associated with higher all-cause mortality (aHR = 1.09, 95% CI: 1.05-1.14), all-cause graft loss (aHR = 1.05, 95% CI: 1.01-1.09), and mortality with functioning graft (aHR = 1.10, 95% CI: 1.05-1.15) risks, but not death-censored graft loss risks, relative to stable weight. Among individuals without obesity, BMI increase was associated with lower all-cause graft loss (aHR = .97, 95% CI: .95-.99) and death-censored graft loss (aHR = .93, 95% CI: .90-.96) risks, but not all-cause mortality or mortality with functioning graft risks. CONCLUSIONS: BMI increases in the 3 years post-KT, then decreases in years 3-5. BMI loss in all adult KT recipients and BMI gain in those with obesity should be carefully monitored post-KT.

Factors impacting the medication "Adherence Landscape" for transplant patients.

BACKGROUND: Medication non-adherence contributes to post-transplant graft rejection and failure; however, limited knowledge about the reasons for non-adherence hinders the development of interventions to improve adherence. We conducted focus groups with solid organ transplant recipients regarding overlooked challenges in the process of transplant medication self-management and examined their adherence strategies and perceptions towards the post-transplant medication regimen. METHODS: We conducted four focus groups with n = 31 total adult transplant recipients. Participants had received kidney, liver, or combined liver/kidney transplant at Johns Hopkins Hospital between 2014 and 2019. Focus groups were audio-recorded and transcribed. Transcripts were analyzed inductively, using the constant comparative method. RESULTS: Responses generally fell into two major categories: (1) barriers to adherence and (2) "adherence landscape". We define the former as factors directly labeled as barriers to adherence by participants and the latter as factors that heavily influence the post-transplant medication self-management process. CONCLUSIONS: We propose a shift in the way healthcare providers and researchers, address the question of medication non-adherence. Rather than asking why patients are non-adherent, we suggest that constructing and understanding patients' "adherence landscape" will provide an optimal way to align the goals of patients and providers and boost health outcomes.

IL-7 receptor heterogeneity as a mechanism for repertoire change during postdepletional homeostatic proliferation and its relation to costimulation blockade-resistant rejection.

Kidney transplant patients treated with belatacept without depletional induction experience higher rates of acute rejection compared to patients treated with conventional immunosuppression. Costimulation blockade-resistant rejection (CoBRR) is associated with terminally differentiated T cells. Alemtuzumab induction and belatacept/sirolimus immunotherapy effectively prevent CoBRR. We hypothesized that cells in late phases of differentiation would be selectively less capable than more naive phenotypes of repopulating postdepletion, providing a potential mechanism by which lymphocyte depletion and repopulation could reduce the risk of CoBRR. Lymphocytes from 20 recipients undergoing alemtuzumab-induced depletion and belatacept/sirolimus immunosuppression were studied longitudinally for markers of maturation (CCR7, CD45RA, CD57, PD1), recent thymic emigration (CD31), and the IL-7 receptor-α (IL-7Rα). Serum was analyzed for IL-7. Alemtuzumab induction produced profound lymphopenia followed by repopulation, during which naive IL-7Rα+ CD57- PD1- cells progressively became the predominant subset. This did not occur in a comparator group of 10 patients treated with conventional immunosuppression. Serum from depleted patients showed markedly elevated IL-7 levels posttransplantation. Sorted CD57- PD1- cells demonstrated robust proliferation in response to IL-7, whereas more differentiated cells proliferated poorly. These data suggest that differences in IL-7-dependent proliferation is one exploitable mechanism that distinguishes CoB-sensitive and CoB-resistant T cell populations to reduce the risk of CoBRR. (ClinicalTrials.gov - NCT00565773.).

Elevated Donor Hemoglobin A1C Impairs Kidney Graft Survival From Deceased Donors With Diabetes Mellitus: A National Analysis.

OBJECTIVES: Kidney transplant is the optimal therapy for patients with end-stage renal disease. The presence of donor diabetes mellitus is a recognized risk factor for impaired kidney graft survival and is incorporated into the Kidney Donor Profile Index. At present, however, there are limited assessments of the severity of this risk factor. Hemoglobin A1c reflects glycemic control over the preceding 3 months, and we hypothesized that donor hemoglobin A1c levels could confer additional discriminatory power in assessments of deceased donors with diabetes mellitus. MATERIALS AND METHODS: The United Network for Organ Sharing/Organ Procurement and Organ Transplantation Network Standard Transplant Analysis Research file was queried for adult deceased-donor kidney transplants performed using allografts from donors with diabetes mellitus who had measurements of hemoglobin A1c before donation. RESULTS: The study cohort consisted of 1518 kidney transplants performed using allografts from deceased donors with diabetes mellitus. Kaplan-Meier survival analysis and log-rank test were performed to compare survival of grafts from donors with diabetes mellitus with elevated (≥ 6.5%) versus lower (< 6.5%) hemoglobin A1c levels. Graft survival at 5 years was significantly lower for recipients of donors with hemoglobin A1c ≥ 6.5% (58.9% vs 68.3%; P < .001). On multivariate analysis, hemoglobin A1c ≥ 6.5% was an independent predictor of diminished graft survival. CONCLUSIONS: Hemoglobin A1c has potential as an additional discriminatory test for estimating outcomes of grafts from donors with diabetes mellitus and should be routinely measured in this population.

Circulating mitochondria in deceased organ donors are associated with immune activation and early allograft dysfunction.

Brain death that occurs in the setting of deceased organ donation for transplantation is associated with systemic inflammation of unknown origin. It has recently been recognized that mitochondria-derived damage-associated molecular patterns (mtDAMPs) released into the circulation in the setting of trauma and tissue injury are associated with a systemic inflammatory response. We examined the blood of deceased organ donors and found elevated levels of inflammatory cytokines and chemokines that correlated with levels of mtDAMPs. We also found that donor neutrophils are activated and that donor plasma contains a neutrophil-activating factor that is blocked by cyclosporin H, a formyl peptide receptor-1 antagonist. Examination of donor plasma by electron microscopy and flow cytometry revealed that free- and membrane-bound mitochondria are elevated in donor plasma. Interestingly, we demonstrated a correlation between donor plasma mitochondrial DNA levels and early allograft dysfunction in liver transplant recipients, suggesting a role for circulating mtDAMPs in allograft outcomes. Current approaches to prolong allograft survival focus on immune suppression in the transplant recipient; our data indicate that targeting inflammatory factors in deceased donors prior to organ procurement is another potential strategy for improving transplant outcomes.

Instituting a Surgical Skills Competition Increases Technical Performance of Surgical Clerkship Students Over Time.

INTRODUCTION: Surgical skills training varies greatly between institutions and is often left to students to approach independently. Although many studies have examined single interventions of skills training, no data currently exists about the implementation of surgical skills assessment as a component of the medical student surgical curriculum. We created a technical skills competition and evaluated its effect on student surgical skill development. METHODS: Second-year medical students enrolled in the surgery clerkship voluntarily participated in a surgical skills competition consisting of knot tying, laparoscopic peg transfer, and laparoscopic pattern cut. Winning students were awarded dinner with the chair of surgery and a resident of their choice. Individual event times and combined times were recorded and compared for students who completed without disqualification. Disqualification included compromising cutting pattern, dropping a peg out of the field of vision, and incorrect knot tying technique. Timed performance was compared for 2 subsequent academic years using Mann-Whitney U test. RESULTS: Overall, 175 students competed and 71 students met qualification criteria. When compared by academic year, 2015 to 2016 students (n = 34) performed better than 2014 to 2015 students (n = 37) in pattern cut (133s vs 167s, p = 0.040), peg transfer (66s vs 101s, p < 0.001), knot tying (28s vs 30s, p = 0.361), and combined time (232s vs 283s, p = 0.009). The best time for each academic year also improved (105s vs 110s). Fundamentals of Laparoscopic Surgery proficiency standards for examined tasks were achieved by 70% of winning students. CONCLUSIONS: Implementation of an incentivized surgical skills competition improves student technical performance. Further research is needed regarding long-term benefits of surgical competitions for medical students.

Necrotizing pancreatitis: challenges and solutions.

Acute pancreatitis is a common disease that can progress to gland necrosis, which imposes significant risk of morbidity and mortality. In general, the treatment for pancreatitis is a supportive therapy. However, there are several reasons to escalate to surgery or another intervention. This review discusses the pathophysiology as well as medical and interventional management of necrotizing pancreatitis. Current evidence suggests that patients are best served by delaying interventions for at least 4 weeks, draining as a first resort, and debriding recalcitrant tissue using minimally invasive techniques to promote or enhance postoperative recovery while reducing wound-related complications.