2020 Research Grant Recipient Synopses

Trisha Blake-Popham, PA-C, MMSc
Hartford Hospital

The Impact of Cold Ischemia Time of High KDPI Graft Function: A Propensity Score Matching Analysis

Following the implementation of the new Kidney Allocation System, Hartford Hospital Transplant Surgery Service developed a protocol to evaluate the utilization of kidneys with KDPI scores ≥85 (K>85) using a systematized algorithm that encompasses metrics beyond KDPI. Upon initial analysis of our K>85cohort, we found excellent 6-month and 1-year function, patient and graft survival, with acceptable perioperative adverse events. We found that, recipient characteristics that predict a 1-year creatinine >1.7 mg/dL were male gender (p=0.016) and African American race (p=0.039) with younger age demonstrating borderline significance (0.075). This work was recognized recently by the American Society of Transplant Surgeons and is in the process of being written for publication. We intend to continue this research by investigating the impact of other peritransplant factors, namely cold ischemic time, on K>85graft function by utilizing data from the Scientific Registry of Transplant Recipients and using propensity score matching analysis.

Katherine Klingenberg, PA-C, MMS
University of Colorado

Creating a Predictive Model for Determining Disposition from the Operating Room following Liver Transplant using Quality Improvement Data and Outcomes

Beginning in October 2018, the University of Colorado liver transplant program has built a quality and process improvement project to decrease ICU admission following liver transplant. By tracking clinical criteria at the end of the liver transplant and creating a PACU extended stay program, we have decreased our post liver transplant ICU admissions by more than 20 percent. Now, more than 60 percent of our liver transplant patients are able to skip the ICU and be safely admitted to the surgical floor. We have seen a significant impact on length of stay and cost. Our project is ongoing and we are hopeful to continue to decrease admissions to the ICU in the future. Additionally, we aim to use the data we have collected to create a predictive model for disposition from the operating room.

Dianne Rudow, DNP, ANP-BC, FAAN
Mount Sinai Hospital (RMTI)

Revision and Validation of the Live Donor Assessment Tool (LDATv2)

Until now, there has been no standardized approach to the psychosocial evaluation of living donors across providers and institutions and no validated psychometric instruments available to determine psychosocial risks for donation. As such, there is variability in evaluations by different teams even in assessing the same patient, and comparing donor evaluations between institutions is very difficult. Our team developed the Live Donor Assessment Tool (LDAT) to assess potential live organ donors. Three published studies found the tool effective in predicting the outcome of the psychosocial evaluation. A multi-center group revised the current tool for clarity and added 4 questions. We aim to determine the validity of the enhanced tool in predicting psychosocial candidacy. This work is invaluable in improving the standardization of selection and safety of care of live donors across transplant centers.

Heather O'Dell, MSN, ANP-BC, MMHC
Vanderbilt University Medical Center

Longitudinal Patient-Reported Outcomes after Living Kidney or Liver Donation: Health-Related Quality of Life, Pain, Activity, Anxiety, and Depression

Literature describing patient-reported outcomes (PROs) after living organ donation, particularly for pain, activity, anxiety, and depression, is limited. Our center has extensive experience evaluating PROs in transplant patients and has reported pilot data in 50 living kidney donors. Preliminary data revealed: 1) statistically significant changes in pre- to post-donation scores for anxiety, depression, physical and social functioning, vitality, mobility, usual activities, pain, and health utility valuations; and 2) between-survey variability in the temporal trajectory of scores’ returning to pre-donation levels. The purpose of this research is to expand the pilot project to living kidney and liver donors using automated, sustainable data acquisition methods with the overall goal of better informing and supporting health care providers and living organ donors regarding post-donation expectations. The specific aim is to determine the trajectory of PROs, including health-related quality of life, pain, activity, and symptoms of anxiety and depression before and after organ donation.

Alex Cuenca, MD, PhD
Boston Children's Hospital

The role of antigen presentation in B regulatory cell function

Allograft survival following transplant has improved dramatically over the last several decades to approximately 80-90% at one year for most organs. While these outcomes are encouraging, patients are maintained on broadly immunosuppressive medications that preserve allograft function but also have untoward effects such as increased rates of both infections and cancer. Therefore, novel approaches are needed to decrease the need for these regimens to preserve allograft function and survival and decrease the morbidity associated with longstanding use of these drugs. One such strategy is through the use of immune cell related therapies. B regulatory cells (B regs) have been demonstrated to arise in multiple inflammatory disease states and are thought to suppress effector T cell responses through the production of the cytokines IL-10 and TGF-b, as well as through the expansion of T regulatory cells. However, the upstream events that regulate these processes is currently unknown. The overarching hypothesis of this proposal is that antigen presentation is critical for B reg associated T cell suppression and allograft associated tolerance. To address this, we will first demonstrate that the development of B reg associated tolerance is antigen specific and related to the antigens present in the milieu at the time of B reg expansion. Next, we will demonstrate that deletion of B cell specific MHCII prevents B reg associated allograft tolerance. In sum, the proposed studies will delineate the role of antigen presentation in B reg function and give insight into how antigen presentation can be exploited for therapeutic purposes.

Narendra Battula, MD, FRCS
University of Florida

Innovative techniques for organ preservation, repair and reconditioning

There is a severe scarcity of donor organs. In order to reduce transplant waitlist mortality by utilization of extended criteria organs (ECD), transplant teams should be provided with tools to estimate and modify the real risks associated with their use. Static cold preservation (SCP) methods have facilitated organ transplantation all over the world for decades. However, emerging evidence demonstrates an increasing challenge to maintain viability of ECD organs with traditional SCP. There is a need to develop innovative preservation techniques, the ideal goal should be to have advanced perfusion systems for organ rehabilitation and validated methods to assess organ viability before transplantation. Perfluorocarbons (PFCs) are biologically inert and effective oxygen carriers with an oxygen solubility approximately 25 times greater than blood or water. We believe that machine perfusion using acellular oxygen carrier can improve organ preservation and cell free DNA (cfDNA) can be used as a surrogate marker to predict quality of preservation and repair of cellular bioenergetics. Here, we propose to test our hypothesis using 1) a porcine DCD kidney machine perfusion model and 2) analysis of perfusate obtained from machine perfused human DCD kidneys, in which cfDNA levels are correlated with measurable clinical outcomes and tested for predictive value.

Juliet Emamaullee, MD, PhD, RCPSC
University of Southern California

Rejection continues to be an important cause of graft loss post-liver transplant (LT), especially in children. The diagnosis of rejection is not predicted by changes in liver function tests and thus requires an invasive biopsy. Meaningful examination of alloreactive lymphocyte populations has been limited by the amount of tissue in a core biopsy and the constraints of immunohistochemistry. My lab is developing novel, high resolution mass cytometry-based techniques to understand which lymphocytes are involved in allogenicity post-LT. Aim 1: Identify, quantify, and determine histological relationships of graft-infiltrating lymphocyte subpopulations during known episodes of ACRpost-LT. Using our novel IMC Liver Immune Panel, we will study patients with known ACR to characterize lymphocyte populations associated with this phage of rejection. Aim 2: Characterize graft-infiltrating lymphocyte subpopulations during known episodes of acute cellular rejection (ACR) post-LT and correlate with blood immune CyTOF profile. Patients will be studied prospectively, with the addition of blood samples taken at the time of biopsy post-LT for analysis with blood-based CyTOF. Significance: Data obtained in this grant will characterize the immune phenotype of ACR in pediatric LT. Importantly, our study design, which is focused on developing techniques that can examine blood and allograft biopsy material simultaneously at the time of rejection will provide information about the utility of blood-based assays as a surrogate marker of subclinical rejection in the graft. If it is possible to detect alloreactive populations within the blood, it would reduce the requirement for biopsy post-LT, which would be particularly relevant for pediatric patients.

Ali Zarrinpar, MD, PhD
University of Florida

Using Phenotypic Precision Medicine to Individualize Immunosuppression Based on Quantifiable Markers of Immune Response and Allograft Injury

We have developed a computational approach, Phenotypic Precision Medicine (PPM), to utilize empiric clinical data to construct patient-specific visual maps that represent each individual’s phenotypic response to drug treatment. Because this process does not require a priori knowledge of disease mechanism, it can effectively personalize drug dosing for any disease despite frequent changes to treatment regimens or patient physiology and genetics. In a pilot randomized controlled trial and its follow-up larger trial, we have shown that transplant patients prospectively dosed with PPM-determined tacrolimus doses had improved drug trough-level management compared with standard of care physician-determined tacrolimus doses. Our ultimate objective in this project is to improve graft and patient outcomes in solid organ transplant recipients by using PPM to optimize immunosuppression dosing. We hypothesize that existing and clinically validated quantifiable markers of immune response and allograft injury are clinically useful measures that can be optimized using PPM. We will test this hypothesis by developing a prospective quantitative liver and kidney allograft monitoring protocol and validate the use of PPM in immunosuppression dosing in kidney and liver transplant recipients. This study constitutes the first step in developing and then validating a personalized immunosuppression platform. The mechanism-independent nature of PPM ensures that it will be adaptive and actionable so that it can be applied to diverse sets of patients. The scalability of PPM also ensures that it can be deployed at a scale that can be applied widely to patients receiving care regardless of location.

Paulo Martins, MD, PhD
University of Massachusetts

RNA Interference During Liver Machine Preservation to Improve Liver Graft Quality

The overall goal of this project is to improve the quality of suboptimal (ischemic) liver grafts. RNA interference (RNAi) is a process through which double-stranded RNA induces the activation of endogenous cellular pathways of RNA degradation, resulting in selective and potent silencing of genes post-transcriptionally that have homology to the double strand. Cellular apoptosis plays an important role in ischemia-reperfusion (I/R) injury during organ transplantation. Synthetic small interference RNA (siRNA) targeting apoptotic receptor FAS has proven effective to prolong survival of allogeneic transplanted hepatocytes, to protect mice against hepatitis and renal I/R injury. The objective of this study is to investigate the treatment with Fas-siRNA during machine preservation to alleviate I/R injury in a model of rat liver reperfusion and liver transplantation. To our knowledge, gene silencing has never been tested in a liver transplant model after machine perfusion preservation. We decided to target FAS because FAS-mediated apoptosis is implicated in a broad spectrum of liver diseases, where inhibiting hepatocyte death is life-saving. Recently, we were the first to demonstrate that siRNA can be delivered to the liver during hypothermic and normothermic machine preservation and now we would like to be the first to test it in a arterialized liver transplant model in the rat.

Joel Adler, MD, MPH
Brigham & Women's Hospital

Development of the Hospital Organ donation Performance Score (HOPS)

There is a clear, worrisome shortage of transplantable organs. Efforts to ameliorate the shortage have predominantly focused on improving processes and procedures among the nation’s Organ Procurement Organizations (OPOs). However, there is no consensus on how to measure the quality of an individual hospital’s organ donation process. Ideally, hospital organ donation performance processes and outcomes would be standardized to enable inter-hospital comparisons; these comparisons could then, in turn, lead to improved OPO performance. We propose to create a reliable metric, utilizing existing measures, to assess individual donor hospital performance. We hypothesize that this tool can distinguish between low-and high-performing donor hospitals, which we will then use to drive performance improvement at the OPO. The advantages of a single metric include ease of interpretation and comparison of performance across hospitals. This project will integrate key metrics into one unified measurement to give a holistic view of hospital performance and reduce the heterogeneity induced by using individual metrics. Ultimately, this will provide feedback and a risk-adjusted comparison of donor hospital performance to drive quality improvement by learning from high-performing hospitals.

Peter Abt, MD, and Joseph Baur, PhD
University of Pennsylvania

Accelerated Liver Defatting During Extracorporeal Organ Perfusion

The shortage of hepatic allografts requires innovative methods to utilize organs considered unsuitable for transplant. The advent of extracorporeal normothermic liver perfusion (ENLP) offers the potential to assess the function of an organ prior to transplant as well as manipulate the organ with the goal of improving organ quality. The extracorporeal nature of the intervention allows application of therapies which would in general be considered to have excessive risk if applied in vivo. We propose utilizing ENLP to defat steatotic (≥15% macrosteatosis) human livers declined for transplant by studying two mechanisms; 1) fat catabolism and 2) fat shedding. 16 discarded steatotic human livers will be divided into 4 groups and perfused on an ENLP circuit supplied with different additives: 1) control group 2) mitochondrial uncoupling with FCCP (fat catabolism) 3) supplementation with nicotinamide riboside (fat catabolism) 3) citicoline (fat shedding). The change in macrosteatosis pre-and post-perfusion will serve as the primary endpoint. Secondary endpoints include the Viability Testing and Transplantation of Marginal Livers criteria (VITTAL) to identify those organs which could be considered suitable for transplant as well as multiple measures of cellular metabolism. The livers will be perfused for up to 18 hours and lipid removed from the circuit with a lipoprotein filter. Given the obesity epidemic in the United States and the shortage of hepatic allografts, defatting livers considered unsuitable for transplant may offer an opportunity to expand the donor pool.

Steven C. Kim, MD
University of Wisconsin 

Mechanisms of Transplant Tolerance Induction with Costimulatory Blockade, Post-Transplant Total Lymphoid Irradiation, and Donor Hematopoietic Stem Cell Infusion

While renal transplantation remains the preferred therapy for end stage renal disease, the challenges of long-term immunosuppression have led researchers to focus on establishing tolerance for recipients. Recently, protocols using costimulatory blockade have been efficacious in preclinical studies of chimerism. Our group is exploring tolerance induction in a non-human primate transplant model using a novel protocol that employs total lymphoid irradiation (TLI) and donor-derived hematopoietic stem cell (HSC) infusions with belatacept adjuvant therapy which has demonstrated efficacy in establishing chimerism. However, the mechanisms by which this protective immunity is conferred need to be elucidated, and the phenotypic makeup of the immune repertoire is largely unstudied in our novel model. We hypothesize that the adjuvant use of costimulatory blockade in our model augments the immunoprotective environment in the immediate engraftment phase and sustains T cell anergy after immune repertoire repopulation, thus allowing for more effective engraftment and sustained chimerism. We first aim to phenotype the peripheral immune and bone marrow compartments at the time of initial engraftment and postoperatively in animals treated with costimulatory blockade. We then aim to investigate the functional fitness of the peripheral immune and bone marrow compartments. Finally, we will withdraw immunosuppression and monitor recipients for graft function and phenotype peripheral T cell repopulation, chimerism, viral reactivation, and donor-specific antibody formation. With more mechanistic insight into how costimulatory blockade may be beneficial in enhancing initial engraftment and sustaining chimerism, we hope to optimize our protocol for eventual tolerance induction in human allotransplantation.

Ciaran O'Brien
University of Pennsylvania

Evaluating the Contribution of the Immune System to Histone Protein Deacetylase 6 Inhibitor Mediated Prevention of Liver Injury after Ischemia-Reperfusion

Ischemia-reperfusion injury (IRI) causes significant morbidity in transplant and other fields. In liver transplantation, IRI may manifest as early allograft dysfunction (EAD) and contributes to early allograft loss. Histone protein deacetylases (HDAC)are a family of regulatory proteins that appear to mediate IRI pathways in liver and other organ systems. We have previously shown in hepatic ischemia that inhibition of HDAC 6, a Class IIb molecule, is profoundly protective. We hypothesize that protective effect of HDAC 6 inhibition is mediated via modulation of the immune response to ischemia reperfusion injury, either through Kupffer cells, the resident hepatic macrophages, or through T cells. Further developing our understanding of mechanism of HDAC6 inhibition in hepatic IRI has the potential to lead to groundbreaking advances in transplantation.

Erin Duggan
Columbia University

Mechanisms of Combined Kidney/Bone Marrow Transplant (CK/BMT) Tolerance using Polyclonal Autologous Tregs to Promote Durable Chimerism in a Translational Model

Immunosuppression, currently critical to prevent rejection of an organ transplant, comes at the cost of the recipient’s ability to fight third-party pathogens, increasing infectious complications and the risk of cardiovascular complications or secondary malignancies. Tolerance of an allograft without immunosuppression would have remarkable impact on the world of transplantation. Using a nonhuman primate model (NHP), it has been found that bone marrow transplantation (BMT) with non-myeloablative conditioning starting 6 days prior to kidney transplant induced transient donor chimerism and permitted acceptance of MHC-mismatched donor kidneys. To compress this protocol, autologous cryopreserved polyclonal T regs, which have been shown in previous NHP studies to enhance the level and duration of chimerism without additional toxicity, will be infused the day of transplantation and will ideally enhance robustness of tolerance. A compressed protocol would allow the use of DDRTs, broadening the clinical application of this strategy. The hypothesis, that long-term donor un/hyporesponsiveness is due to deletion of donor-reactive T cells and expansion of donor-reactive T regs, will be tested by applying high throughput T cell receptor (TCR) sequencing to track the expansion and contraction of different T cell populations from pre-transplant to the endpoints of rejection or 1-year survival. TCR sequencing will also be used to study T cell populations in the BM of tolerant animals, providing a basis for understanding the mechanism by which T regs promote durable chimerism. It is expected that achieving durable chimerism and tolerance in this translational model will lead to the development of tolerance induction protocols for future clinical trials.

Aileen Johnson
Emory University

The Metagenomic Landscape of Pancreas Transplant Febrile Syndrome

Patients with advanced diabetes complicated by renal disease can be effectively treated with simultaneous pancreas and kidney transplant. Approximately a quarter of these patients experience pancreas transplant febrile syndrome (PTFS) during their postoperative course, resulting in prolonged hospitalization and lengthy workups. Identifying an etiology for PTFS and understanding its interaction with the immune system will pave the way for improving outcomes of this disease. We aim to compare the viromes of patients who develop PTFS with uncomplicated transplant patients. We hypothesize that patients who develop PTFS will have signature differences in their microvirome. We will quantify these differences to isolate an etiologic agent. We will also examine whether patient immune factors such as immune cell phenotypes have any effect on duration or severity of disease. Using shotgun-metagenomics, we will characterize the microviromes of pancreas transplant patients with and without PTFS to identify a candidate etiologic agent. We will isolate viral DNA from patient samples, assemble a library of sequences, align sequence fragments, and perform BLAST analysis to classify viruses. PCR analysis will allow for quantitative measure of viral burden, to assess for a temporal relationship with documented clinical symptoms of disease. Using flow cytometry, we will examine immune cell phenotypes in these different groups to assess clustering and activation or exhaustion phenotypes. The presence of these phenotypes will be analyzed against the duration and severity of clinical symptoms. Finally, we will use predictive modeling to determine if baseline immune cell phenotype is associated with risk of developing PTFS.

Dominic Amara
University of California, San Francisco

Establishing a Molecular Signature of Late Acute Cellular Rejection in Liver Transplant Recipients

Late acute cellular rejection (ACR), usually defined as acute rejection more than6 months after transplant, has been associated with inferior patient and graft survival after liver transplant compared with recipients who experience early ACR. Despite these different clinical outcomes, it remains unclear whether late ACR is a distinct clinical entity from early ACR. Histologically, the two phenomena appear similar. However, the molecular pathways leading to each phenomenon have not been delineated. Whether it is one similar molecular pathway or multiple distinct molecular pathways that lead to a similar histological picture is unclear. Therefore, the purpose of this proposed study is to explore the gene expression profiles in transplant liver biopsies with early and late ACR.

Hannah Burris
University of Florida College of Medicine

Evaluation of statins as cancer chemoprophylactic agents in chronic liver disease

Chronic liver diseases, especially nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), constitute an increasing global problem. The most common and fastest growing liver disease, NAFLD may progress to cirrhosis and hepatocellular carcinoma (HCC), especially when accompanied by the presence of type 2 diabetes mellitus (T2DM), obesity, or metabolic syndrome.12Now the second leading indication for liver transplant in the US, NASH is expected to become the most common indication within the next decade.2,3With this increase, transplant burden has also increased, creating an urgent need for pharmacological intervention strategies. A growing body of evidence suggests that cholesterol-lowering statins, or 3-hyrdoxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, may be related to decreased risk of cancers including HCC. There is also evidence suggesting a dose-and duration-dependent relationship. In this study, we will utilize the One Florida i2b2 data repository to access a standardized, de-identified, and non-duplicative database to examine this relationship in a diverse sample that is representative of the population of the entire state of Florida. This approach is crucial to assessing chronic liver disease in a Western setting, where NAFLD is a more likely etiology than viral hepatitis. In patients with chronic liver disease, we will assess for comorbidities of interest such as cancer, hyperlipidemia, and T2DM, as well as medication use, especially of statins and other metabolic drugs to assess their efficacy as cancer chemoprophylactic agents.

Samantha Cawthon
NYU Grossman School of Medicine

Implementation of Protocolized Infectious Disease Surveillance System in Recently Deceased Human Xenograft Study

The solid organ transplant waitlist grows each year and thousands die while waiting for life-saving treatment. Xenotransplantation is a potential solution for this organ shortage but has been slow to develop because of immunological challenges and fear of zoonosis. This concern for xenozoonosis originates from zoonotic epidemics, such as the current coronavirus outbreak, known porcine viruses, and unknown microbes, which is further exacerbated by our lack of human xenograft clinical data. As primate xenograft studies have a limited ability to model the human immune response, an intermediate step is necessary before human clinical trials can begin. This summer, I will work with Dr. Robert Montgomery, director of the NYU Langone Transplant Institute, to implement a protocolized infectious disease surveillance system for his upcoming study placing genetically engineered porcine kidneys in an ex vivo perfusion circuit with brain dead (recently deceased)humans. This study provides the ability to obtain functional organ data and monitor for zoonosis without introducing the risk of exposure to a living human subject. Asa recently deceased human xenograft study has not been previously conducted, a well-defined protocol to monitor for zoonosis must be developed. The main objectives of this surveillance system are to stratify the risk of pathogens with genetically engineered porcine grafts and to determine the testing and sample storage protocol. The implementation of this surveillance system intends to verify the low risk of zoonosis, supporting the safety of xenotransplantation and the possibility of a renewable source of transplantable organs.

Samantha Halpern
Duke University

Use of Sirtuin-1 Activators to Mitigate Ischemia-Reperfusion Injury after Liver Transplantation

Ischemia-reperfusion (IR) injury induces mitochondrial dysfunction and damage that contributes to cell death, metabolic derangements, and energy depletion within liver allografts. Sirtuin-1 is an energy-sensing NAD-dependent deacetylase that responds to cellular stress in low-energy states. Prior studies suggest that sirtuin-1 aids mitochondrial recovery after IR injury by improving clearance of damaged mitochondria and enhancing mitochondrial biogenesis. Work from our group has corroborated findings from other studies, which demonstrated that pharmacologic activation of sirtuin-1 improves cell survival in an in vitro model of hepatic IR injury. These findings provide indirect evidence to support the role of sirtuin-1 in mitochondrial recovery after IR injury. However, direct evidence to elucidate the specific mechanism by which sirtuin-1 improves hepatocyte survival is currently lacking. We hypothesize that pharmacologic activation of sirtuin-1 improves mitochondrial respiratory function, thereby contributing to improved cell survival after IR injury. We propose to use our in vitro model of hepatic IR injury to explore the direct effects of pharmacologic activation of sirtuin-1 on mitochondrial function. We will employ the Agilent Seahorse XF Mito Stress Test assay to quantify hepatocyte oxygen consumption rate after simulated IR injury as a direct measure of mitochondrial respiratory function. We will compare oxygen consumption rates among controls, vehicle-treated, and sirtuin-1 activator-treated cells to determine whether sirtuin-1 activation improves mitochondrial function after IR injury. The findings of this study may support the use of sirtuin-1 activators as a potential therapeutic avenue by which to mitigate IR injury and improve outcomes after liver transplantation.

Jessica Lovett
NYU Grossman School of Medicine

Investigating the impact of intra-operative verapamil administration on graft function of high-risk deceased donor kidney transplants.

Advances in immunosuppression therapy have significantly reduced acute-graft rejection; however, there
has been no analogous improvement in long-term graft survival. Long-term allograft function is impacted by the ischemia reperfusion injury (IRI) that occurs during transplantation. Prior studies suggest that IRI is due in part to imbalances in calcium homeostasis. Specifically, the reperfusion of a recently transplanted organ is accompanied by a rapid rise in intracellular calcium. This insult activates several calcium-dependent mechanisms, resulting in membrane and cytoskeletal destruction, DNA fragmentation, inflammation and apoptosis. Calcium channel blockers (CCBs) have been used to prevent graft injury during transplant. However, it remains unknown if the administration of CCBs significantly improves long-term graft survival. The goal of the current study is to determine if the administration of intra-operative verapamil, a commonly utilized CCB, significantly impacts kidney transplant graft function in recipients of DCD kidneys.

Christopher Morris
University of Cincinnati

Education on organ donation should start in medical school: Development of a formalized medical student organ procurement curriculum

Chloe Nobuhara
Duke University

Examining the Depletional Profile of the Anti-CD2 Monoclonal Antibody TCD-601 and Its Effect on Co-Stimulation Blockade Based Immunosuppression in Non-Human Primates

Kidney transplantation is a life-sustaining treatment for end-stage renal disease. However, current immunosuppressive regimens contribute to significant morbidity in transplant patients. The most commonly used drugs, calcineurin inhibitors (CNIs) and glucocorticoids, have unfavorable cardiovascular and metabolic side effects. Co-stimulation blockade (CoB) has less off-target effects but increased rates of acute rejection have limited its widespread application. T-cell depletion with the anti-CD2 monoclonal antibody (mAb) TCD-601 may augment CoB with the CTLA-4-Ig belatacept. CD2 is expressed on mature T-cells in humans and depletion by this mechanism may lead to subsequent repopulation with a naïve population of T-cells. Belatacept is most effective at inhibiting naïve CD28+ T cells. We therefore propose to determine the depletional profile of TCD-601 in rhesus macaques as well as the ability of TCD-601 to prevent CoB resistant rejection (CoBRR)in a well-established nonhuman primate model (NHP) of kidney transplantation. We will treat three rhesus macaques with TCD-601 without renal transplantation and three with renal transplantation and belatacept immunosuppression. In the first experimental group, we will evaluate the lymphocyte depleting effects of TCD-601 in both the peripheral blood and lymph nodes by flow cytometry and histology. In the second experimental group, we will determine the ability of TCD-601 to augment CoB based immunosuppression in an NHP model. In addition to standard flow cytometric analysis we will also serially test alloresponsiveness by mixed lymphocyte reactions. We will also test the ability of TCD-601 induction to improve survival compared to historical controls who received belatacept alone for immunosuppression.

Jeffrey Ord
Duke University

Clinical Correlates and Mechanistic Underpinnings of Costimulation Blockade Resistant Rejection (CoBRR) Mediated by CD57+PD1- CD4 T Cells

Maintenance therapy in kidney transplant utilizes calcineurin inhibitor (CNI) based regiments which are nephrotoxic and have infectious complications. Belatacept works through co-stimulation blockade (CoB), avoiding the complications of CNI therapies. However, belatacept therapies have higher rates of early acute cellular rejection. One study found that CD57+PD1-CD4 T cells are present in patients with CoB-resistant rejection (CoBRR). These cells exhibit pro-inflammatory properties that implicate them in CoBRR. Understanding the clinical correlates of CD57+ PD1-CD4 T cell development and mechanisms by which these cells contribute to CoBRR may aid the development of CNI free regimens. We will examine peripheral blood mononuclear cells (PBMCs) samples from 50 potential kidney transplant recipients and 50 patients before and after transplant by flow cytometry and correlate patient demographics and clinical characteristics. We will follow transplant recipients over time. Our preliminary experiments found that CD57+PD1-CD4 T cells are only able to proliferate with CD3/28 monoclonal antibody stimulation in the presence of bulk autologous PBMCs. We wish to further characterize the mechanisms necessary for this proliferation. Utilizing supernatants from sorted, proliferating, VPD-labeled CD57+ PD1-CD4 T cells we will characterize the proliferative cytokine milieu using cytokine arrays. We will then perform relevant cytokine blocking experiments to determine which cytokines are integral to proliferation. To explore the role of cell-cell contact in signaling, we will perform a transwell experiment with VPD-labeled CD57+ PD1-CD4+T cells to assess the ability of these cells to proliferate without direct contact and whether they migrate towards stimulated bulk PBMC.

Jon Sussman
Mayo Clinic- Arizona

Variation in Perioperative Opioid Prescribing Patterns in Abdominal Transplantation

The inappropriate prescription of opioids is a significant contributor to the opioid epidemic in the United States despite many efforts to regulate prescribing and reduce diversion from clinical use.(1, 2)Robust and broadly accepted guidelines for perioperative pain management are not widely utilized in transplantation. This proposal aims to evaluate the role of opioid prescribing variation within and between transplant centers for abdominal transplant procedures and how this affects long term recipient outcomes. An additional aim of this proposal is to begin development of decision-support tools for to assist clinicians and patients in post-transplant pain management following hospital discharge. As a student with a strong interest in transplantation and quality improvement, this project will clarify how perioperative opioid prescribing may contribute to substance misuse or substance use disorders, insights into whether transplant provider prescribing affects opioid diversion into the community, and how opioid use may affect transplant outcomes. This serves the interests of transplant patients, transplant centers, organ donors and their families, and the public. To date, there has not been substantial research devoted to variation in prescribing patterns between different organ transplant procedures, differences within transplant centers, and differences between transplant centers for the same transplant procedures. We will study these issues by analyzing opioid prescribing patterns at three high-volume academic transplant centers. By identifying variation in prescription volume, refill utilization, and other associated predictors of misuse both within and between centers, we will help define best practices in the perioperative management of pain after transplant.

Ashley Yoo
University of Maryland

Defining Baseline Levels of dd-cfDNA within One Year of Pancreas Transplantation to Evaluate the Potential Use of dd-cfDNA as an Indicator for Pancreas Rejection and Pancreas Biopsy Avoidance

Donor-derived cell free DNA (dd-cfDNA) can be used as a “liquid biopsy” to predict rejection in patients who have undergone kidney transplants (KTx). This allows dd-cfDNA to detect rejection earlier than previously thought and helps predict the utility of biopsy in recipients thought to exhibit rejection. Often, the sooner a rejection is found and treated, the better the outcome will be. dd-cfDNA technology has not yet been adapted to pancreas transplantation (PTx). As such, it is possible that dd-cfDNA can also predict rejection after pancreas transplantation. Pancreas transplants have a higher rate of rejection-related graft loss than do kidneys, suggesting that the pancreas is more alloreactive than the kidney, following transplantation. Thus, we hypothesize that peripheral blood dd-cfDNA elevation can be associated with, and thus act as a biomarker for, pancreatic allograft rejection. Not only is rejection more common after pancreas transplantation, but also pancreas transplant biopsies are technically difficult and can contribute to potential patient morbidity. For these reasons, dd-cfDNA is an appealing potential approach to the rejection diagnosis. Up to this point, preliminary data has been collected, and the results show that, in non-rejecting simultaneous pancreas-kidney transplant (SPK) and PTx alone (PTA)recipients, dd-cfDNA is detectable and suggests that the median baseline level of dd-cfDNA in non-rejecting SPK and PTA recipients is greater than the median reported for KTx recipients without active rejection. Additional patient enrollment will improve characterization of baseline dd-cfDNA levels in PTx recipients to establish a minimum dd-cfDNA cutoff level for active PTx rejection status.