Cellular dynamics in pig-to-human kidney xenotransplantation.

BACKGROUND: Xenotransplantation of genetically engineered porcine organs has the potential to address the challenge of organ donor shortage. Two cases of porcine-to-human kidney xenotransplantation were performed, yet the physiological effects on the xenografts and the recipients' immune responses remain largely uncharacterized. METHODS: We performed single-cell RNA sequencing (scRNA-seq) and longitudinal RNA-seq analyses of the porcine kidneys to dissect xenotransplantation-associated cellular dynamics and xenograft-recipient interactions. We additionally performed longitudinal scRNA-seq of the peripheral blood mononuclear cells (PBMCs) to detect recipient immune responses across time. FINDINGS: Although no hyperacute rejection signals were detected, scRNA-seq analyses of the xenografts found evidence of endothelial cell and immune response activation, indicating early signs of antibody-mediated rejection. Tracing the cells' species origin, we found human immune cell infiltration in both xenografts. Human transcripts in the longitudinal bulk RNA-seq revealed that human immune cell infiltration and the activation of interferon-gamma-induced chemokine expression occurred by 12 and 48 h post-xenotransplantation, respectively. Concordantly, longitudinal scRNA-seq of PBMCs also revealed two phases of the recipients' immune responses at 12 and 48-53 h. Lastly, we observed global expression signatures of xenotransplantation-associated kidney tissue damage in the xenografts. Surprisingly, we detected a rapid increase of proliferative cells in both xenografts, indicating the activation of the porcine tissue repair program. CONCLUSIONS: Longitudinal and single-cell transcriptomic analyses of porcine kidneys and the recipient's PBMCs revealed time-resolved cellular dynamics of xenograft-recipient interactions during xenotransplantation. These cues can be leveraged for designing gene edits and immunosuppression regimens to optimize xenotransplantation outcomes. FUNDING: This work was supported by NIH RM1HG009491 and DP5OD033430.

Integrative multi-omics profiling in human decedents receiving pig heart xenografts.

In a previous study, heart xenografts from 10-gene-edited pigs transplanted into two human decedents did not show evidence of acute-onset cellular- or antibody-mediated rejection. Here, to better understand the detailed molecular landscape following xenotransplantation, we carried out bulk and single-cell transcriptomics, lipidomics, proteomics and metabolomics on blood samples obtained from the transplanted decedents every 6 h, as well as histological and transcriptomic tissue profiling. We observed substantial early immune responses in peripheral blood mononuclear cells and xenograft tissue obtained from decedent 1 (male), associated with downstream T cell and natural killer cell activity. Longitudinal analyses indicated the presence of ischemia reperfusion injury, exacerbated by inadequate immunosuppression of T cells, consistent with previous findings of perioperative cardiac xenograft dysfunction in pig-to-nonhuman primate studies. Moreover, at 42 h after transplantation, substantial alterations in cellular metabolism and liver-damage pathways occurred, correlating with profound organ-wide physiological dysfunction. By contrast, relatively minor changes in RNA, protein, lipid and metabolism profiles were observed in decedent 2 (female) as compared to decedent 1. Overall, these multi-omics analyses delineate distinct responses to cardiac xenotransplantation in the two human decedents and reveal new insights into early molecular and immune responses after xenotransplantation. These findings may aid in the development of targeted therapeutic approaches to limit ischemia reperfusion injury-related phenotypes and improve outcomes.

Electronic health record-enabled routine assessment of medication adherence after solid organ transplantation: the time is now.

Medication nonadherence after solid organ transplantation is recognized as an important impediment to long-term graft survival. Yet, assessment of adherence is often not part of routine care. In this Personal Viewpoint, we call for the transplant community to consider implementing a systematic process to screen and assess medication adherence. We believe acceptable tools are available to support integrating adherence assessments into the electronic health record. Creating a standard assessment can be done efficiently and cost-effectively if we come together as a community. More importantly, such monitoring can improve outcomes and strengthen provider-patient relationships. We further discuss the practical challenges and potential rebuttals to our position.

Immune response, phenotyping and molecular graft surveillance in kidney transplant recipients following severe acute respiratory syndrome coronavirus 2 vaccination.

BACKGROUND: Understanding immunogenicity and alloimmune risk following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in kidney transplant recipients is imperative to understanding the correlates of protection and to inform clinical guidelines. METHODS: We studied 50 kidney transplant recipients following SARS-CoV-2 vaccination and quantified their anti-spike protein antibody, donor-derived cell-free DNA (dd-cfDNA), gene expression profiling (GEP), and alloantibody formation. RESULTS: Participants were stratified using nucleocapsid testing as either SARS-CoV-2-naïve or experienced prior to vaccination. One of 34 (3%) SARS-CoV-2 naïve participants developed anti-spike protein antibodies. In contrast, the odds ratio for the association of a prior history of SARS-CoV-2 infection with vaccine response was 18.3 (95% confidence interval 3.2, 105.0, p < 0.01). Pre- and post-vaccination levels did not change for median dd-cfDNA (0.23% vs. 0.21% respectively, p = 0.13), GEP scores (9.85 vs. 10.4 respectively, p = 0.45), calculated panel reactive antibody, de-novo donor specific antibody status, or estimated glomerular filtration rate. CONCLUSIONS: SARS-CoV-2 vaccines do not appear to trigger alloimmunity in kidney transplant recipients. The degree of vaccine immunogenicity was associated most strongly with a prior history of SARS-CoV-2 infection.

Immune response after pig-to-human kidney xenotransplantation: a multimodal phenotyping study.

BACKGROUND: Cross-species immunological incompatibilities have hampered pig-to-human xenotransplantation, but porcine genome engineering recently enabled the first successful experiments. However, little is known about the immune response after the transplantation of pig kidneys to human recipients. We aimed to precisely characterise the early immune responses to the xenotransplantation using a multimodal deep phenotyping approach. METHODS: We did a complete phenotyping of two pig kidney xenografts transplanted to decedent humans. We used a multimodal strategy combining morphological evaluation, immunophenotyping (IgM, IgG, C4d, CD68, CD15, NKp46, CD3, CD20, and von Willebrand factor), gene expression profiling, and whole-transcriptome digital spatial profiling and cell deconvolution. Xenografts before implantation, wild-type pig kidney autografts, as well as wild-type, non-transplanted pig kidneys with and without ischaemia-reperfusion were used as controls. FINDINGS: The data collected from xenografts suggested early signs of antibody-mediated rejection, characterised by microvascular inflammation with immune deposits, endothelial cell activation, and positive xenoreactive crossmatches. Capillary inflammation was mainly composed of intravascular CD68+ and CD15+ innate immune cells, as well as NKp46+ cells. Both xenografts showed increased expression of genes biologically related to a humoral response, including monocyte and macrophage activation, natural killer cell burden, endothelial activation, complement activation, and T-cell development. Whole-transcriptome digital spatial profiling showed that antibody-mediated injury was mainly located in the glomeruli of the xenografts, with significant enrichment of transcripts associated with monocytes, macrophages, neutrophils, and natural killer cells. This phenotype was not observed in control pig kidney autografts or in ischaemia-reperfusion models. INTERPRETATION: Despite favourable short-term outcomes and absence of hyperacute injuries, our findings suggest that antibody-mediated rejection in pig-to-human kidney xenografts might be occurring. Our results suggest specific therapeutic targets towards the humoral arm of rejection to improve xenotransplantation results. FUNDING: OrganX and MSD Avenir.

Pig-to-human heart xenotransplantation in two recently deceased human recipients.

Genetically modified xenografts are one of the most promising solutions to the discrepancy between the numbers of available human organs for transplantation and potential recipients. To date, a porcine heart has been implanted into only one human recipient. Here, using 10-gene-edited pigs, we transplanted porcine hearts into two brain-dead human recipients and monitored xenograft function, hemodynamics and systemic responses over the course of 66 hours. Although both xenografts demonstrated excellent cardiac function immediately after transplantation and continued to function for the duration of the study, cardiac function declined postoperatively in one case, attributed to a size mismatch between the donor pig and the recipient. For both hearts, we confirmed transgene expression and found no evidence of cellular or antibody-mediated rejection, as assessed using histology, flow cytometry and a cytotoxic crossmatch assay. Moreover, we found no evidence of zoonotic transmission from the donor pigs to the human recipients. While substantial additional work will be needed to advance this technology to human trials, these results indicate that pig-to-human heart xenotransplantation can be performed successfully without hyperacute rejection or zoonosis.

A systematic review of direct acting antiviral therapies in hepatitis C virus-negative liver transplant recipients of hepatitis C-viremic donors.

The introduction of safe and highly effective direct acting antivirals (DAAs) has significantly improved hepatitis C virus (HCV) treatment outcomes after transplant. The solid organ transplant community has sought to identify strategies aimed at increasing the donor pool including the utilization of HCV-viremic organs in HCV-negative recipients. We will review the existing literature to evaluate DAA use for the treatment of HCV viremia post-liver transplant in patients who receive HCV-viremic allografts. A PubMed search was conducted and references for each study were also reviewed to identify additional articles. Randomized controlled trials, cohort studies, case series, and case reports were included if: published in English language, evaluated DAA treatment outcomes after liver only or simultaneous liver-kidney transplantation with HCV-viremic allografts in HCV-negative recipients, and had full-text article availability. Our review included 16 studies and 2 case reports. The majority of liver transplant recipients were treated with a pangenotypic DAA for 12 weeks with a heterogeneous median time to initiation (range 1.7-118 days). Sustained virologic response was assessed in 253 liver transplant patients with 99.6% achieving cure with minimal DAA-attributed adverse drug events. There were 23 reported episodes of rejection, 12 deaths, and 1 graft loss among all studies. Treatment with DAA after transplantation of HCV-viremic livers into HCV-negative recipients appears to be safe and effective; however, long-term outcomes remain unknown. Transplant pharmacists play a key role in the development of center-specific protocols to optimize post-transplant outcomes in this unique patient population.

Transplant Pharmacists' Experience With Telehealth During the COVID-19 Pandemic.

BACKGROUND: The adoption of telehealth became a necessity for healthcare organizations during the COVID-19 pandemic. Transplant pharmacists are integral members of the multi-disciplinary care team who quickly adapted application of these technologies to ensure continuity of care. OBJECTIVE: To assess transplant pharmacists' experience with telehealth during the COVID-19 pandemic. METHODS: A 23-question online survey was developed to assess transplant pharmacists' experience with telehealth during the COVID-19 pandemic. RESULTS: Forty-five pharmacists responded to the survey from a broad range of transplant centers. The majority of respondents indicated infrequent use of telehealth (98%) before the COVID-19 pandemic, but this was significantly changed during the pandemic with only 9% reporting infrequent use. Pharmacists anticipated a decrease in future use, but 91% of respondents stated they would like to continue utilization of telehealth in their practice post-pandemic. CONCLUSIONS: The adoption of telehealth during COVID-19 was widespread and has the potential to facilitate continuity of care. Though pharmacists anticipated a decrease in future use, a majority favored continued utilization of telehealth in their practice.

The Impact of the COVID-19 Pandemic on the Transplant Pharmacist Workforce.

Background: The COVID-19 pandemic has placed an unprecedented strain on the US healthcare system, greatly impacting transplant centers. Objective: The purpose of this survey was to evaluate the impact of the COVID-19 pandemic on the transplant pharmacist workforce. Methods: A survey was disseminated electronically to assess the impact of the COVID-19 pandemic on the transplant pharmacist workforce. Respondents were asked to give background regarding transplant center, patient, population, and departmental staffing. Results: There were 67 total respondents from 56 transplant centers. In response to the COVID-19 pandemic, 55% of centers reported stopping non-life saving transplants, and a majority (89%) stopped living donor transplants altogether. The banning of caregivers on-site during education, reduction of bedside education teaching, and cancelling of group teaching classes occurred at 46%, 40%, and 22% of centers, respectively. Consequently, 42% of pharmacists surveyed felt that their confidence in patient and caregiver's understanding of medications had decreased since these changes have been implemented. Conclusions: Pharmacist perception of patient and caregiver understanding of transplant medications has decreased since before the COVID-19 pandemic. As health systems strategize resource allocation throughout the pandemic, the importance of patient education must be prioritized to sustain and improve transplant outcomes.

The use of non-transplant biologics in solid organ transplant recipients: A practical review for the frontline clinician.

Biologics have become the forefront of medicine for management of autoimmune conditions, leading to improved quality of life. Many autoimmune conditions occur in solid organ transplant (SOT) recipients and persist following transplant. However, the use of biologics in this patient population is not well studied, and questions arise related to risk of infection and adjustments to induction and maintenance immunosuppression. Guidelines have been published highlighting management strategies of biologics around the time of elective surgical procedures, but this is not always feasible in urgent situations, especially with deceased donor transplantation. The aim of this review is to summarize the current literature regarding the use of these agents in solid organ transplant recipients, and specifically address induction and maintenance immunosuppression, as well as the need for alternative infective prevention strategies to create a practical reference for the frontline clinician, when faced with this complex clinical scenario.

Clinical and Financial Implications of 2 Treatment Strategies for Donor-derived Hepatitis C Infections.

Transplanting hepatitis C viremic donor organs into hepatitis C virus (HCV)-negative recipients is becoming increasingly common; however, practices for posttransplant direct-acting antiviral (DAA) treatment vary widely. Protracted insurance authorization processes for DAA therapy often lead to treatment delays. METHODS: At our institution, 2 strategies for providing DAA therapy to HCV- recipients of HCV+ transplants have been used. For thoracic organ recipients, an institution-subsidized course of initial therapy was provided to ensure an early treatment initiation date. For abdominal organ recipients, insurance approval for DAA coverage was sought once viremia developed, and treatment was initiated only once the insurance-authorized supply of drug was received. To evaluate the clinical impact of these 2 strategies, we retrospectively collected data pertaining to the timing of DAA initiation, duration of recipient viremia, and monetary costs incurred by patients and the institution for patients managed under these 2 DAA coverage strategies. RESULTS: One hundred fifty-two transplants were performed using HCV viremic donor organs. Eighty-nine patients received DAA treatment without subsidy, and 62 received DAA treatment with subsidy. One patient who never developed viremia posttransplant received no treatment. Subsidizing the initial course enabled earlier treatment initiation (median, 4 d [interquartile range (IQR), 2-7] vs 10 [IQR, 8-13]; P < 0.001) and shorter duration of viremia (median, 16 d [IQR, 12-29] vs 36 [IQR, 30-47]; P < 0.001). Institutional costs averaged $9173 per subsidized patient and $168 per nonsubsidized patient. Three needlestick exposures occurred in caregivers of viremic patients. CONCLUSIONS: Recipients and their caregivers stand to benefit from earlier DAA treatment initiation; however, institutional costs to subsidize DAA therapy before insurance authorization are substantial. Insurance authorization processes for DAAs should be revised to accommodate this unique patient group.

Professional and pre-professional pharmacy students' perceptions of team based learning (TBL) at a private research-intensive university.

BACKGROUND AND PURPOSE: Pharmacy students need to develop critical thinking and problem-solving skills as well as be a valuable team member. The use of team based learning (TBL) fosters effective team collaboration, enables continuous active and self-directed learning, and requires both individual and team accountability. The purpose was to evaluate pharmacy students' perceptions and experiences related to TBL in different years of the pharmacy curriculum. EDUCATIONAL ACTIVITY AND SETTING: Two classes, Introduction to the Profession of Pharmacy (intro), a required course, and Self-Care/Non-Prescription Medications (self-care), an elective course, utilize the TBL approach. Students enrolled in both courses were recruited to complete a validated questionnaire during the last class. FINDINGS: There was 100% participation; the majority of students, regardless of course, expressed positive attitudes towards TBL. Variations, relevance of TBL activities and the use of TBL as a learning strategy, between the required intro class and the elective self-care class were observed using a Mann-Whitney U test (p<0.05). DISCUSSION: Both cohorts of pharmacy students positively rated the TBL sessions in terms of learning effectiveness. It's important to consider the differences in professional development in these students and how this may impact their perceptions of TBL. TBL imparts more responsibility and accountability on the individual student allowing for the development of self-directed learners. SUMMARY: Students, regardless of their year, found TBL to be an effective learning strategy. Third professional year (P3) pharmacy students further along in the curriculum are more accepting of TBL and are better able to appreciate the benefits of active and self-directed learning as well as working within a team.