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.
View Article and Find Full Text PDFGenetically 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.
View Article and Find Full Text PDFA 57-year-old man with nonischemic cardiomyopathy who was dependent on venoarterial extracorporeal membrane oxygenation (ECMO) and was not a candidate for standard therapeutics, including a traditional allograft, received a heart from a genetically modified pig source animal that had 10 individual gene edits. Immunosuppression was based on CD40 blockade. The patient was weaned from ECMO, and the xenograft functioned normally without apparent rejection.
View Article and Find Full Text PDFBackground: Xenografts from genetically modified pigs have become one of the most promising solutions to the dearth of human organs available for transplantation. The challenge in this model has been hyperacute rejection. To avoid this, pigs have been bred with a knockout of the alpha-1,3-galactosyltransferase gene and with subcapsular autologous thymic tissue.
View Article and Find Full Text PDFBackground: Recent advances in gene editing technology have enabled the production of multi-knockout (KO) and transgenic pigs in order to overcome immunologic barriers in xenotransplantation (XTx). However, the genetic manipulations required to produce these changes may have the unintended consequence of producing or revealing neoantigens reactive with natural antibodies present in baboons. In this study, we examined whether the neoantigens that develop in multi-transgenic (mTg) GalT, Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH), β-1,4-N-acetyl-galactosaminyl transferase 2 (B4) KO pigs can cause rejection of xenografts in baboons.
View Article and Find Full Text PDFXenotransplantation
January 2020
Background: We have recently demonstrated that human-CD47 (hCD47) expressed on endothelial cells of porcine lung xenografts extended median graft survival from 3.5 days to 8.7 days in baboons.
View Article and Find Full Text PDFPurpose Of Review: Xenotransplantation offers the opportunity to alleviate the imbalance between the demand of patients with end stage organ failure and the supply of organs available for transplantation but remains aspirational. This review highlights how collaboration between academia and industry are essential for success.
Recent Findings: The science of xenotransplantation has accelerated in recent years with key discoveries in genetic engineering, enabling disruption of genes facilitating rejection, and transgenic expression of desired human genes.
Xenotransplantation
September 2018
Background: Despite recent progress in survival times of xenografts in non-human primates, there are no reports of survival beyond 5 days of histologically well-aerated porcine lung grafts in baboons. Here, we report our initial results of pig-to-baboon xeno-lung transplantation (XLTx).
Methods: Eleven baboons received genetically modified porcine left lungs from either GalT-KO alone (n = 3), GalT-KO/humanCD47(hCD47)/hCD55 (n = 3), GalT-KO/hD47/hCD46 (n = 4), or GalT-KO/hCD39/hCD46/hCD55/TBM/EPCR (n = 1) swine.
Background: Ligands activating the transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) have antiinflammatory effects. Vascular rejection induced by allogeneic T cells can be responsible for acute and chronic graft loss. Studies in rodents suggest that PPARγ agonists may inhibit graft vascular rejection, but human T-cell responses to allogeneic vascular cells differ from those in rodents, and the effects of PPARγ in human transplantation are unknown.
View Article and Find Full Text PDFBackground: The reasons for kidney allograft failure subsequent to pancreas after kidney (PAK) are multifactorial; therefore, we examined these factors to identify a meaningful risk assessment that could assist in patient selection.
Methods: Five transplant centers in New England collaborated for this multiinstitutional retrospective study of 126 PAK transplantation recipients who had a functioning pancreas allograft 7 days after transplantation. Host factors (age at pancreas transplant, gender, body weight, glomerular filtration rate at 3 months pre-PAK and at 3-, 6-, 9-, and 12-month post-PAK, presence of proteinuria, pre- or post-PAK kidney rejection, pancreas rejection, cytomegalovirus disease, and HbA1C at 6-month post-PAK) and transplant factors (time to PAK, use of induction antibody therapy, and combinations of immunosuppressive medications) were assessed in both univariate and multivariate analyses for the primary outcome of kidney allograft failure.
BACKGROUND.: Sirolimus (SRL) is an important component of clinical immunosuppression in renal transplantation, but few international studies have examined how this agent is used in routine practice. METHODS.
View Article and Find Full Text PDFBackground: Nearly half of all infiltrating leukocytes in rejecting human allografts are macrophages, yet, in comparison with T cells, much less is known about the contribution of this cell type to rejection. Our laboratory has previously described models of rejection of human skin or artery grafts in immunodeficient mouse hosts mediated by adoptively transferred allogeneic T cells. However, mature human monocyte/macrophages have consistently failed to engraft in these animals.
View Article and Find Full Text PDFGoals: To determine the efficacy and safety of combination therapy in patients with hepatitis C virus (HCV) and end-stage renal disease (ESRD).
Background: There is little data on the treatment of ESRD patients with pegylated interferon and ribavirin. We designed a pilot study to determine the initial and 12-week posttreatment viral response.
Background: Graft arteriosclerosis (GA) is an important factor limiting long-term outcomes after organ transplantation. We have used a chimeric humanized mouse system to model this arteriopathy in human vessels, and found that the morphologic and functional changes of experimental GA are interferon (IFN)-gamma dependent. This study evaluated whether 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, described as inhibitors of IFN-gamma production, affect GA in our model.
View Article and Find Full Text PDFVascular remodeling rather than intimal thickening is the most important determinant of luminal loss in cardiac graft arteriosclerosis. The impact of donor-transmitted atherosclerotic lesions on alloimmune-mediated arterial injury in an experimental setting is not known. We investigated this issue in a chimeric model of human coronary artery grafts to immunodeficient mouse recipients reconstituted with allogeneic human peripheral blood mononuclear cells.
View Article and Find Full Text PDFIn practical terms, regardless of HLA compatibility level, whenever tissues are transplanted from one person to another it is essential to suppress the immune response of the recipient. A variety of methods are available however, the most frequently used ones have the disadvantage of being immunologicaly non specific. The consequence is a difficult balance between immunosuppression sufficient to prevent the tissue rejection and maintenance of immune system at the level of ability to adequately deal with an infection.
View Article and Find Full Text PDFArch Pediatr Adolesc Med
May 2006
Background: Chronic allograft dysfunction may result from arterial injury, manifest as transplant arteriosclerosis (TA). This represents an important factor limiting long-term outcomes after heart and kidney transplantation; a relationship between acute allograft arterial injury and TA has been suggested. We have used SCID/bg mice bearing transplanted human artery, inoculated with allogeneic human PBMC to study arteriopathy in human vessels.
View Article and Find Full Text PDFBackground: Blockade of the renin-angiotensin-aldosterone system in the early post-transplant period remains controversial. Angiotensin II-receptor blockers (ARB) have many benefits to the patient with chronic kidney disease and these benefits may also apply to the renal transplant recipient (RTR). Additionally, there are theoretical benefits of ARB use in RTR.
View Article and Find Full Text PDFBackground: This 36-month, randomized, parallel-group study compared safety and efficacy of two doses of everolimus with mycophenolate mofetil (MMF) in de novo renal-transplant recipients.
Methods: Renal-allograft recipients received 1.5 mg/day or 3 mg/day of everolimus or 2 g/day of MMF, plus full-dose cyclosporine (CsA) and corticosteroids after randomization.
Strict consideration of the renal transplant candidate's chronologic age is generally supplanted by more subjective reflection on his (her) physiologic state. In the US, patients over 64 years old represented 9.0% of renal transplant recipients in the year 2000, yet little prior experience is available with which to guide the management of geriatric patients.
View Article and Find Full Text PDFThe aims of the current study were to determine whether therapeutic drug monitoring (TDM) might benefit kidney transplant recipients receiving everolimus, and to establish dosage recommendations when everolimus is used in combination with cyclosporine and corticosteroids. The analysis was based on data from 779 patients enrolled in two 12-month trials. Everolimus trough concentrations >/=3 ng/mL were associated with a reduced incidence in biopsy-proven acute rejection (BPAR) in the first month (p = 0.
View Article and Find Full Text PDFThis study presents the first prospective multicenter study assessing sirolimus-based immunosuppression with early (4-day) corticosteroid withdrawal (CSWD) in renal transplantation. Immunosuppression included: anti-IL-2 receptor antibody and tacrolimus/sirolimus. Inclusion criteria included adult primary recipients.
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