Organ Grafts Research Articles

Unveiling the Metabolic Trajectory of Pig Feces Across Different Ages and Senescence.

Porcine models are increasingly recognized for their similarities to humans and have been utilized in disease modeling and organ grafting research. While extensive metabolomics studies have been conducted in swine, primarily focusing on conventional cohorts or specific animal models, the composition and functions of fecal metabolites in pigs across different age groups-particularly in the elderly-remain inadequately understood. In this study, an untargeted metabolomics approach was employed to analyze the fecal metabolomes of pigs at three distinct age stages: young (one year), middle-aged (four years), and elderly (eight years). The objective was to elucidate age-associated changes in metabolite composition and functionality under standardized rearing conditions. The untargeted metabolomic analysis revealed a diverse array of age-related metabolites. Notably, L-methionine sulfoxide levels were found to increase with age, whereas cytidine-5-monophosphate levels exhibited a gradual decline throughout the aging process. These metabolites demonstrated alterations across various biological pathways, including energy metabolism, pyrimidine metabolism, lipid metabolism, and amino acid metabolism. Collectively, the identified key metabolites, such as L-methionine sulfoxide and Cholecalciferol, may serve as potential biomarkers of senescence, providing valuable insights into the mechanistic understanding of aging in pigs.

Silane modified Cr2O3/polyimide nanocomposite films with excellent surface insulation performance for space applications

The exploration of deep space significantly increases the probability of spacecraft failures due to surface electrostatic discharge, which imposes higher vacuum insulation protection requirements on polyimide (PI), the external insulation material of spacecrafts. To address this challenge, this study proposes using silane coupling agent KH550 for organic grafting treatment of Cr2O3nanoparticles, which are then used to dope and modify PI to enhance the vacuum surface insulation of PI films. The KH550 grafting improves the interface strength between the fillers and the matrix, allowing the fillers to be uniformly dispersed in the matrix. Compared to pure PI films, the prepared PI-Cr2O3@KH550 composite films exhibit significantly enhanced vacuum surface flashover voltage, improved surface/volume resistivity, and dielectric properties. The results demonstrate that PI composite films with 0.8% by mass of Cr2O3@KH550 show the most notable performance improvement, with the DC flashover voltage and impulse flashover voltage in vacuum increasing by 20.7% and 27.8%, respectively. The doping of chromium oxide nanoparticles introduces more deep traps into the PI films and reduce the surface resistivity. The higher deep trap density inhibits charge migration, thereby alleviating secondary electron emission and surface electric field distortion. Simultaneously, the lower surface resistivity facilitates dissipating surface charges and improves the surface insulation. These findings are of significant reference value for promoting the enhancement of aerospace insulation performance.

Impact of machine perfusion on transplant infectious diseases: New challenges and opportunities.

Preservation techniques that maintain the viability of an organ graft between retrieval from the donor and implantation into the recipient remain a critical aspect of solid organ transplantation. While traditionally preservation is accomplished with static cold storage, advances in ex vivo dynamic machine perfusion, both hypothermic and normothermic, have allowed for prolongation of organ viability and recovery of marginal organs effectively increasing the usable donor pool. However, the use of these novel machine perfusion technologies likely exposes the recipient to additional infectious risk either through clonal expansion of pathogens derived during organ recovery or de novo exogenous acquisition of pathogens while the organ remains on the machine perfusion circuit. There is a paucity of high-quality studies that have attempted to quantify infection risk, although it appears that prolonging the time on the machine perfusion circuit and normothermic parameters increases the risk of infection. Conversely, the use of ex vivo machine perfusion unlocks new opportunities to detect and treat donor-derived infections before implantation into the recipient. This review seeks to reveal how the use of ex vivo machine perfusion strategies may augment the risk of infection in the organ recipient as well as outline ways that this technology could be leveraged to enhance our ability to manage donor-derived infections.

Expanding the Donor Pool to the Ultimate Level: Introducing the Revolutionary Hybrid Dual Graft Liver Transplant Using Domino and Living Donors.

Innovative solutions are crucial as the demand for liver transplants continues to outpace available grafts. Dual graft liver transplantation offers a promising avenue to address graft volume challenges while minimizing donor risks. This report introduces a groundbreaking approach, combining a full organ domino donor graft with a living donor graft for a hybrid dual graft liver transplant. A 2-y-old child with Maple syrup urine disease and a 40-y-old adult with end-stage liver disease became the focus of this unique case. A hybrid dual graft liver transplant was executed, uniting the domino donor's full organ graft with a living donor's left lateral segment. Precise vascular and biliary reconstructions facilitated a successful transplant. The hybrid dual graft liver transplant, merging domino donor and living donor grafts, presents a viable strategy to combat graft shortages, particularly in regions predominantly reliant on living donor transplants. Despite challenges, this pioneering approach should be embraced by established liver transplant centers because it enables concurrent living donor liver transplantation while prioritizing donor safety and recipient outcomes.

#2992 Risk and prognostic factors for post-transplantation lymphoproliferative disease in solid organ transplant recipients—a multicenter analysis

Abstract Background and Aims Post-transplantation lymphoproliferative disorder (PTLD), a potentially fatal complication of transplantation, affects solid organ transplant recipients at different rates, depending on organ graft type: the risk greater in lung transplant recipients (LngTRs), lower for liver transplant recipients (LTRs) and lowest for kidney transplant recipients (KTR). In this study we aimed to investigate the factors affecting the development and treatment outcomes of PTLD and compare their effect on KTRs, LTRs and LngTRs. Method In this retrospective cohort study we have included all KTRs, LTRs and LngTRs diagnosed with PTLD at six transplantation centers in Poland. The data collected from medical records included: immunosuppression (IS), viral infections, PTLD type, treatment and outcomes. Chi-squared test was used to assess the differences in group composition. To determine the impact of variables upon PTLD time of onset and patient survival, univariate Cox regression was used. p-values below 0.05 were considered statistically significant. Results We enrolled 50 KTRs, 36 LTRs and 5 LngTRs from 6 transplantation centers in Poland. Based on the data from the most contributing centers in each group, the prevalence of PTLD was 0.82% of KTRs, 2.03% LTRs and 1.51% of LngTRs. Two thirds of the enrolled patients were male, the median age at first transplantation was 40 years for KTRs, 45 for LTRs and 25 for LngTRs (Table 1). The groups significantly differed in IS treatment: steroid (GCS) and cyclosporin (CsA) use was more frequent in KTRs (p<0.001 and p<0.001 and respectively), tacrolimus (TAC) and anti-CD25 induction in LTRs (p ≤ 0.001 and p<0.001 respectively), sirolimus (RAPA) in LngTRs (p<0.001). KTRs were the latest to develop PTLD (126 months after transplantation, p<0.001). In all groups Monomorphic B-cell PTLD was the most frequent. Initial IS treatment reduction was used in 80-86% of patients, R-CHOP chemotherapy was most common in LTRs (p=0.021), other chemotherapy regimens in KTRs (p=0.031). TAC had the opposite effect on PTLD time of onset in KTRs (HR=2.18, p=0.013) and LTRs (HR=0.18, p=0.036). The overall survival at the end of observation period was 26% for KTRs, 58% for LTRs and 80% for LngTRs. Loss to follow up was most frequent in KTRs at 26%. Patient survival was not affected by PTLD treatment. Conclusion KTRs develop PTLD later than LTRs and LngTRs, and time of disease onset is associated with TAC use. Lower survival in KTRs may result from the longer follow-up period compared to other solid organ transplant recipients.

Organ donation after extracorporeal cardiopulmonary resuscitation: a nationwide retrospective cohort study

BackgroundLimited data are available on organ donation practices and recipient outcomes, particularly when comparing donors who experienced cardiac arrest and received extracorporeal cardiopulmonary resuscitation (ECPR) followed by veno-arterial extracorporeal membrane oxygenation (ECMO) decannulation, versus those who experienced cardiac arrest without receiving ECPR. This study aims to explore organ donation practices and outcomes post-ECPR to enhance our understanding of the donation potential after cardiac arrest.MethodsWe conducted a nationwide retrospective cohort study using data from the Japan Organ Transplant Network database, covering all deceased organ donors between July 17, 2010, and August 31, 2022. We included donors who experienced at least one episode of cardiac arrest. During the study period, patients undergoing ECMO treatment were not eligible for a legal diagnosis of brain death. We compared the timeframes associated with each donor’s management and the long-term graft outcomes of recipients between ECPR and non-ECPR groups.ResultsAmong 370 brain death donors with an episode of cardiac arrest, 26 (7.0%) received ECPR and 344 (93.0%) did not; the majority were due to out-of-hospital cardiac arrests. The median duration of veno-arterial ECMO support after ECPR was 3 days. Patients in the ECPR group had significantly longer intervals from admission to organ procurement compared to those not receiving ECPR (13 vs. 9 days, P = 0.005). Lung graft survival rates were significantly lower in the ECPR group (log-rank test P = 0.009), with no significant differences in other organ graft survival rates. Of 160 circulatory death donors with an episode of cardiac arrest, 27 (16.9%) received ECPR and 133 (83.1%) did not. Time intervals from admission to organ procurement following circulatory death and graft survival showed no significant differences between ECPR and non-ECPR groups. The number of organs donated was similar between the ECPR and non-ECPR groups, regardless of brain or circulatory death.ConclusionsThis nationwide study reveals that lung graft survival was lower in recipients from ECPR-treated donors, highlighting the need for targeted research and protocol adjustments in post-ECPR organ donation.

The Role of Low-level Laser in Organ Transplantation

Organ transplantation means removing an organ (graft) from one person's body and transferring and placing it in the body of another person who has a defect in the function of the organ in question.

RORγt inverse agonist TF-S14 inhibits Th17 cytokines and prolongs skin allograft survival in sensitized mice

Chronic antibody mediated rejection (AMR) is the major cause of solid organ graft rejection. Th17 contributes to AMR through the secretion of IL17A, IL21 and IL22. These cytokines promote neutrophilic infiltration, B cell proliferation and donor specific antibodies (DSAs) production. In the current study we investigated the role of Th17 in transplant sensitization. Additionally, we investigated the therapeutic potential of novel inverse agonists of the retinoic acid receptor-related orphan receptor gamma t (RORγt) in the treatment of skin allograft rejection in sensitized mice. Our results show that RORγt inverse agonists reduce cytokine production in human Th17 cells in vitro. In mice, we demonstrate that the RORγt inverse agonist TF-S14 reduces Th17 signature cytokines in vitro and in vivo and leads to blocking neutrophilic infiltration to skin allografts, inhibition of the B-cell differentiation, and the reduction of de novo IgG3 DSAs production. Finally, we show that TF-S14 prolongs the survival of a total mismatch grafts in sensitized mice. In conclusion, RORγt inverse agonists offer a therapeutic intervention through a novel mechanism to treat rejection in highly sensitized patients.

UV-curable organic silicone grafting modified waterborne polyurethane acrylate: Preparation and properties

The organosilicon grafting copolymerization waterborne polyurethane acrylate composite coating (WPUA@KH570) with high surface properties was prepared by the UV curing method from mixing silicone monomer surface-modified ZnO (Si@ZnO) as photoinitiator to waterborne polyurethane acrylate (WPUA) emulsion. The effects of the polyurethane isocyanate index (R), the addition amount of hydrophilic chain elongator DMBA (wDMBA), the ratio of PU/PA on the stability of the synthesized WPUA emulsion were explored. The properties of the WPUA@KH570 composite coatings with different contents of organosilicon surface-modified ZnO were characterized by the particle size distribution meter, FTIR, XRD, SEM, UV–Vis–NIR spectrophotometer, contact angle (CA) and water absorption rate (WAR). The results showed that when R = 1.4, wDMBA = 0.04 and PU/PA = 0.6, the WPUA emulsion had an excellent stability. When the content of organosilicon modified ZnO reached 1.5 wt%, the CA increased to 90.6°, the WAR decreased to 15.4 %, and the absorbance reached 0.5. The WPUA@KH570 composite coating could be changed from hydrophilic to hydrophobic, which can step further promoted the surface properties, water resistance and UV absorption.

Risk Factors for Solid Organ Graft Failure and Death in Solid Organ Transplant Recipients Undergoing Hematopoietic Cell Transplantation: A Center for International Blood and Marrow Transplant Research Study

Risk Factors for Solid Organ Graft Failure and Death in Solid Organ Transplant Recipients Undergoing Hematopoietic Cell Transplantation: A Center for International Blood and Marrow Transplant Research Study

A narrow T cell receptor repertoire instructs thymic differentiation of MHC class Ib-restricted CD8+ regulatory T cells.

Although most CD8+ T cells are equipped to kill infected or transformed cells, a subset may regulate immune responses and preserve self-tolerance. Here, we describe a CD8 lineage that is instructed to differentiate into CD8 T regulatory cells (Tregs) by a surprisingly restricted set of T cell receptors (TCRs) that recognize MHC-E (mouse Qa-1) and several dominant self-peptides. Recognition and elimination of pathogenic target cells that express these Qa-1-self-peptide complexes selectively inhibits pathogenic antibody responses without generalized immune suppression. Immunization with synthetic agonist peptides that mobilize CD8 Tregs in vivo efficiently inhibit antigraft antibody responses and markedly prolong heart and kidney organ graft survival. Definition of TCR-dependent differentiation and target recognition by this lineage of CD8 Tregs may open the way to new therapeutic approaches to inhibit pathogenic antibody responses.

Pressing ethical issues relating to clinical pig organ transplantation studies.

Clinical pig heart transplant experiments have been undertaken, and further clinical experiments and/or clinical trials of gene-edited pig organ xenotransplantation are anticipated. The ethical issues relating to xenotransplantation have been discussed for decades but with little resolution. Consideration of certain ethical issues is more urgent than others, and the need to attain consensus is important. These issues include: (i) patient selection criteria for expanded access and/or clinical trials; (ii) appropriate protection of the patient from xenozoonoses, that is, infections caused by pig microorganisms transferred with the organ graft, (iii) minimization of the risk of a xenozoonosis to bystanders, and (iv) the need for additional public perception studies. We discuss why it is important and urgent to achieve consensus on these ethical issues prior to carrying out further expanded access experiments or initiating formal clinical trials. The ways forward on each issue are proposed.

Mesenchymal Stem Cells and Tissue Bioengineering Applications in Sheep as Ideal Model.

The most common technologies in tissue engineering include growth factor therapies; metal implants, such as titanium; 3D bioprinting; nanoimprinting for ceramic/polymer scaffolds; and cell therapies, such as mesenchymal stem cells (MSCs). Cell therapy is a promising alternative to organ grafts and transplants in the treatment of numerous musculoskeletal diseases. MSCs have increasingly been used in generative medicine due to their specialized self-renewal, immunomodulation, multiplication, and differentiation properties. To further expand the potential of these cells in tissue repair, significant efforts are currently dedicated to the production of biomaterials with desirable short- and long-term biophysical properties that can aid the differentiation and expansion of MSCs. Biomaterials support MSC differentiation by modulating their characteristics, such as composition, mechanical properties, porosity, and topography. This review aimed to describe recent MSC approaches, including those associated with biomaterials, from experimental, clinical, and preclinical studies with sheep models.

Multivariate surface self-assembly strategy to fabricate ionic covalent organic framework surface grafting monolithic sorbent for enrichment of aristolochic acids prior to high performance liquid chromatography analysis

Herein, an ionic covalent organic framework (iCOF) surface grafting monolithic sorbent was prepared by the multivariate surface self-assembly strategy for in-tube solid-phase microextraction (SPME) of trace aristolochic acids (AAs) in serum, traditional Chinese medicines (TCMs) and Chinese patent drug. Via adjusting the proportion of ionic COF building block during the self-assembly, the density of quaternary ammonium ions in the iCOF was modulated for the enhanced adsorption of AAs. The successful preparation of iCOF surface grafting monolithic sorbent was confirmed by different means. A multiple mode mechanism involving π-π stacking, hydrophobic, electrostatic and hydrogen-bonding interactions was primarily attributed to the adsorption. Several in-tube SPME operating conditions, such as the dosage of ionic COF building block, ACN percentage and TFA percentage in the sampling solution, ACN percentage and TFA percentage in eluent and the collection time span, were optimized to develop the online in-tube SPME-HPLC method for analysis of AAs. Under the optimized conditions, a good linearity was obtained in the concentration range of 20–1000 ng/mL for target AAs in serum samples, the limits of detection (LODs) were less than 10 ng/mL, while the recoveries ranged from 90.3 % to 98.7 % with RSDs (n = 5) below 7.9 %. This study developed a feasible approach to iCOF functionalized monolithic sorbent for SPME and further exhibited the vast potential for the application of COF based monolithic sorbent in sample preparation.

The effect of donor graft type on survival after liver transplantation for hepatoblastoma in children.

Liver transplantation (LT) is the only potentially curative option for children with unresectable hepatoblastoma (HBL). Although post-transplant outcomes have improved in the contemporary era, the impact of donor graft type on survival remains unclear. Using the United Network for Organ Sharing database (02/2002-06/2021), demographics, clinical characteristics, and patient and graft survival were analyzed in children (<18 years) who underwent LT for HBL according to donor graft type. The Kaplan-Meier method, log-rank tests, and Cox regression modeling were used to evaluate the effect of whole, partial, and split deceased donor liver transplantation (DDLT) and living donor liver transplantation (LDLT) on patient and graft survival. A total of 590 pediatric HBL LT recipients (344 whole graft DDLT; 62 partial graft DDLT; 139 split graft DDLT; 45 LDLT) were included. During 2012-2021 the proportion of LDLTs for HBL decreased to about 5% compared with about 11% during 2002-2011. No significant differences were identified by donor graft type in either patient survival (log-rank test, p = .45) or graft survival (log-rank test, p = .69). The results remained similar during the 2002-2011 era, while during the 2012-2021 era, split graft DDLT was associated with decreased graft loss risk versus whole graft DDLT (hazard ratio: 0.48, 95% confidence interval: 0.23-0.99, p = .046) without any other significant between-group differences. Utilizing non-whole liver grafts can increase access to LT in children with unresectable HBL while ensuring favorable outcomes. LDLT is underutilized in children with HBL in the United States, and efforts to explore LDLT options should be undertaken.

Abstract 12159: Heart Generation via Blastocyst Complementation in Mesp1/2-Deficient Mice

Introduction: Heart transplantation is the only curative option available for patients with advanced heart failure. However, donor organ shortage and graft rejection remain critical challenges in heart transplantation. Blastocyst complementation using pluripotent stem cells (PSCs) can be used to generate organs such as the pancreas and kidneys in animal models with abnormalities in essential developmental genes. Nonetheless, whether functional adult hearts can be generated with blastocyst complementation remains unclear, and it is unknown if parenchyma, blood vessels, and stroma can be generated concomitantly from PSCs using blastocyst complementation to avoid graft rejection. Methods: We generated functional hearts in acardiac Mesp1 and Mesp2 double-knockout (Mesp1/2-DKO) mice via blastocyst complementation using mouse and rat PSCs. Results: The generated adult murine hearts were structurally and functionally normal and restored embryonic lethality in Mesp1/2-DKO mice. All four cardiovascular lineages, including cardiomyocytes, vascular endothelial cells, smooth muscle cells, and cardiac fibroblasts, were virtually entirely derived from exogenous PSCs in the myocardium. Exogenous rat PSCs also generated rat-derived xenogeneic hearts in Mesp1/2-DKO mice via interspecies blastocyst complementation. Conclusions: Blastocyst complementation is a viable technique for generating hearts derived from PSCs and may represent significant progress toward generating rejection-free hearts.

Magnetic Janus micromotors for fluorescence biosensing of tacrolimus in oral fluids

Tacrolimus (FK506) is a macrolide lactone immunosuppressive drug that is commonly used in transplanted patients to avoid organ rejection. FK506 exhibits high inter- and intra-patient pharmacokinetic variability, making monitoring necessary for organ graft survival. This work describes the development of a novel bioassay for monitoring FK506. The bioassay is based on using polycaprolactone-based (PCL) magnetic Janus micromotors and a recombinant chimera receptor that incorporates the immunophilin tacrolimus binding protein 1A (FKBP1A) tagged with Emerald Green Fluorescent Protein (EmGFP). The approach relies on a fluorescence competitive bioassay between the drug and the micromotors decorated with a carboxylated FK506 toward the specific site of the fluorescent immunophilin. The proposed homogeneous assay could be performed in a single step without washing steps to separate the unbound receptor. The proposed approach fits the therapeutic requirements, showing a limit of detection of 0.8 ng/mL and a wide dynamic range of up to 90 ng/mL. Assay selectivity was evaluated by measuring the competitive inhibition curves with other immunosuppressive drugs usually co-administered with FK506. The magnetic propulsion mechanism allows for efficient operation in raw samples without damaging the biological binding receptor (FKBP1A-EmGFP). The enhanced target recognition and micromixing strategies hold considerable potential for FK506 monitoring in practical clinical use.

Role of perfusion medium in rewarming machine perfusion from hypo- to normothermia.

Gradual warming up of cold stored organ grafts using a controlled machine perfusion protocol facilitates restitution of cellular homeostasis and mitigates rewarming injury by adapted increase of temperature and metabolism. The aim of the present study was to compare intra- and extracellular type perfusion media for the use in machine perfusion-assisted rewarming from hypo- to normothermia. Rat livers were retrieved 20 min after cardiac arrest. After 18 h of cold storage (CS) with or without additional 2 h of rewarming machine perfusion from 8°C up to 35°C with either diluted Steen solution or with Belzer MPS, liver functional parameters were evaluated by an established exvivo reperfusion system. Rewarming machine perfusion with either solution significantly improved graft performance upon reperfusion in terms of increased bile production, less enzyme release, and reduced lipid peroxidation compared to CS alone. Cellular apoptosis (release of caspase-cleaved keratin 18) and release of tumor necrosis factor were only reduced significantly after machine perfusion with Belzer MPS. Histological evaluation did not disclose any major morphological damage in any of the groups. Within the limitation of our model, the use of Belzer MPS seems to be an at least adequate alternative to a normothermic medium like Steen solution for rewarming machine perfusion of cold liver grafts.

Preserved 2-y Liver Transplant Outcomes Following Simultaneous Thoracoabdominal DCD Organ Procurement Despite Effects on Liver Utilization Rate.

Current techniques for donation after circulatory determination of death (DCD) heart procurement, through either direct procurement and machine perfusion or thoracoabdominal normothermic regional perfusion (NRP), have demonstrated excellent heart transplant outcomes. However, the impact of thoracoabdominal DCD (TA-DCD) heart procurement on liver allograft outcomes and utilization is poorly understood. One hundred sixty simultaneous heart and liver DCD donors were identified using the United Network for Organ Sharing/Organ Procurement and Transplantation Network database between December 2019 and July 2021. Liver outcomes from TA-DCD donors were stratified by heart procurement technique and evaluated for organ utilization, graft survival, and patient survival. Results were compared with abdominal-only DCD (A-DCD; n = 1332) and donation after brain death (DBD; n = 12 891) liver transplants during the study interval. Kaplan-Meier methods with log-rank testing were used to evaluate patient and graft survival. One hundred thirty-three of 160 livers procured from TA-DCD donors proceeded to transplant. TA-DCD donors were younger (mean 28.26 y; P < 0.0001) with lower body mass index (mean 26.61; P < 0.0001) than A-DCD and DBD donors. TA-DCD livers had equivalent patient survival ( P = 0.893) and superior graft survival (P = 0.009) compared with A-DCD. TA-DCD livers had higher rates of organ discard for long warm ischemia time (37.0%) than A-DCD (20.5%) and DBD (0.5%; P < 0.0001), with direct procurement and machine perfusion procurements leading to a higher discard rate (18.5%) than NRP procurements (7.4%). Liver transplants after TA-DCD donation demonstrated equivalent patient outcomes and excellent graft outcomes. NRP procurements resulted in the lowest rate of organ discard after DCD donation and may represent an optimal strategy to maximize organ utilization.

Interleukin-7 improves the fitness of regulatory T cells for adoptive transfer.

Adoptive regulatory T-cell (Treg) transfer has emerged as a promising therapeutic strategy for regulating immune responses in organ transplantation, graft versus host disease, and autoimmunity, including Type 1 diabetes. Traditionally, Treg for adoptive therapy have been sorted and expanded in vitro using high doses of IL-2, demonstrating stability and suppressive capabilities. However, limitations in their long-term survival post-infusion into patients have been observed. To address this challenge, we investigated a novel expansion protocol incorporating interleukin-7 (IL-7) alongside the traditional method utilizing IL-2 (referred to as IL-7 method, IL-7M). Our study revealed that naïve Treg express significant levels of CD127 and display robust responsiveness to IL-7, characterized by STAT-5 phosphorylation. Expanding naïve Treg with the IL-7M protocol led to a substantial enrichment of CD45RA+ CD62L+ CD95+ Treg but showing a reduction in the final cell yield and suppressive function. Moreover, Treg expanded with the IL-7M exhibited preserved telomere length and demonstrated enhanced resistance to cytokine withdrawal and fas-mediated apoptosis. When transferred into NSG mice IL-7M-Treg persisted longer and reduced the expansion of T cells, but did not significantly reduce the severity of xenoGvHD. In conclusion, our data demonstrate the feasibility of expanding naïve Treg in the presence of IL-7 to generate a Treg product enriched in poorly differentiated CD45RA+ cells with enhanced survival capabilities.