Improved Graft Survival Research Articles

Micro/Nanobubble-Assisted Lipotransfer: In Vivo Evidence of Improved Graft Outcomes.

Retention rates of lipotransfer remain variable, with the underlying cause associated with tissue oxygenation and blood supply barriers. One promising new method of improving tissue oxygenation is micro/nanobubbles (MNBs), which are small gas bubbles (<100 μm) generated within a saline solution. MNBs are stable and carry a significant amount of oxygen, and because of their negatively charged surface characteristics, they are an ideal oxygen-delivery solution. Thus, we hypothesize that washing/oxygenating lipoaspirate tissue prior to transplantation in a micro/nanobubble saline solution will improve graft survival and quality compared to a saline control. Human lipoaspirate samples obtained from healthy donors were washed with an oxygenated MNB or saline wash. These samples were then injected into the dorsum of sixteen 6-week-old male BALB/c mice, where each mouse received one saline and one MNB-washed graft. At 2-, 4-, 8-, and 12-week time points, the explants were harvested and weighed, and gas pycnometry was performed to assess graft volume. The tissues were also subjected to hematoxylin and eosin (HE) staining and immunohistochemistry to detect perilipin and blood vessels (CD31). These stains, as well as adipocyte count and area quantifications, were analyzed using ImageJ. HE staining revealed that the control group demonstrated notable adipocyte hypertrophy, while MNB-washed samples had evident adipocyte hyperplasia. This observation was confirmed by an analysis of variance (ANOVA), which showed that the control group had a larger average graft mass and volume (P < 0.01). MNB-washed grafts also exhibited significantly greater adipocyte counts and smaller adipocytes (P < 0.001). Perilipin staining was also greater in the MNB group at the 2- and 4-week time point indicating improved de novo adipogenesis following implantation. Lastly, CD31 staining revealed a significantly greater core vessel density and angiogenesis at the 4-week and 12-week time points (P < 0.01). Our study demonstrates that MNBs enhance tissue quality as indicated by a significant increase in de novo adipogenesis, higher vessel density, and decreased adipocyte hypertrophy. Additional studies are needed to evaluate the clinical effectiveness. Nevertheless, incorporating MNBs into procedures holds great promise in tackling the ongoing challenge of inconsistent outcomes in lipotransfer.

Use of Machine Perfusion in the United States Increases Organ Utilization and Improves DCD Graft Survival in Liver Transplantation.

Adoption of machine perfusion (MP) technology has rapidly expanded in liver transplantation without real-world data on utilization and outcomes, which are critical to understand the appropriate application of MP technology. The Organ Procurement and Transplant Network/Standard Transplant Analysis and Research database was used to identify all deceased donor livers procured with intent for transplant between October 27, 2015 (date of first recorded MP) and June 30, 2023 (n = 67 795). Liver allografts were cohorted by donation after brain death (DBD; n = 59 957) or circulatory death (DCD; n = 7873) and analyzed by static cold storage (SCS) or MP preservation method. Donor demographics, organ utilization, and graft survival were evaluated. By 2023, 12.5% of all livers and 37.2% of DCD livers underwent MP preservation (82.6% normothermic, 6.7% hypothermic, and 10.8% other/unknown). Compared with SCS, MP liver donors were older (DBD: 48 versus 40 y [P < 0.001]; DCD: 43 versus 38 y [P < 0.001]) with higher body mass index (DBD: 28.8 versus 26.9 kg/m2 [P < 0.001]; DCD: 27.7 versus 26.9 kg/m2 [P = 0.004]). Donor livers had similar levels of macrosteatosis (median 5%). Graft utilization was higher for MP than SCS after DBD (96.4% versus 93.0%, P < 0.001) and DCD (91.4% versus 70.3%, P < 0.001) donation. Graft survival was similar between MP and SCS livers from DBD donors (P = 0.516), whereas MP-preserved grafts had superior survival from DCD donors at 1 and 3 y posttransplant (P = 0.013 and 0.037). Patient survival was similar across all groups at 3 y (P = 0.322). The use of MP in liver transplantation increased rates of liver utilization and improved graft survival after DCD. Further monitoring of MP outcomes is required to understand long-term benefits.

Assessing Methods for Adjusting Estimates of Treatment Effectiveness for Patient Nonadherence in the Context of Time-to-Event Outcomes and Health Technology Assessment: A Simulation Study.

We aim to assess the performance of methods for adjusting estimates of treatment effectiveness for patient nonadherence in the context of health technology assessment using simulation methods. We simulated trial datasets with nonadherence, prognostic characteristics, and a time-to-event outcome. The simulated scenarios were based on a trial investigating immunosuppressive treatments for improving graft survival in patients who had had a kidney transplant. The primary estimand was the difference in restricted mean survival times in all patients had there been no nonadherence. We compared generalized methods (g-methods; marginal structural model with inverse probability of censoring weighting [IPCW], structural nested failure time model [SNFTM] with g-estimation) and simple methods (intention-to-treat [ITT] analysis, per-protocol [PP] analysis) in 90 scenarios each with 1,900 simulations. The methods' performance was primarily assessed according to bias. In implementation nonadherence scenarios, the average percentage bias was 20% (ranging from 7% to 37%) for IPCW, 20% (8%-38%) for SNFTM, 20% (8%-38%) for PP, and 40% (20%-75%) for ITT. In persistence nonadherence scenarios, the average percentage bias was 26% (9%-36%) for IPCW, 26% (14%-39%) for SNFTM, 26% (14%-36%) for PP, and 47% (16%-72%) for ITT. In initiation nonadherence scenarios, the percentage bias ranged from -29% to 110% for IPCW, -34% to 108% for SNFTM, -32% to 102% for PP, and between -18% and 200% for ITT. In this study, g-methods and PP produced more accurate estimates of the treatment effect adjusted for nonadherence than the ITT analysis did. However, considerable bias remained in some scenarios. Randomized controlled trials are usually analyzed using the intention-to-treat (ITT) principle, which produces a valid estimate of effectiveness relating to the underlying trial, but when patient adherence to medications in the real world is known to differ from that observed in the trial, such estimates are likely to result in a biased representation of real-world effectiveness and cost-effectiveness.Our simulation study demonstrates that generalized methods (g-methods; IPCW, SNFTM) and per-protocol analysis provide more accurate estimates of the treatment effect than the ITT analysis does, when adjustment for nonadherence is required; however, even with these adjustment methods, considerable bias may remain in some scenarios.When real-world adherence is expected to differ from adherence observed in a trial, adjustment methods should be used to provide estimates of real-world effectiveness.

Efficacy of a Standardized Regimen of Therapeutic Plasma Exchange and IVIG for Treatment of Antibody-Mediated Rejection in Lung Transplant Recipients.

Antibody-mediated rejection (AMR) in lung transplantation has been associated with poor long-term clinical course and is a risk factor for chronic lung allograft dysfunction and graft loss. Appropriate management of AMR is necessary to improve graft survival in lung transplant recipients. There is currently no standardized approach to the treatment of lung AMR, and practices vary by institution. We sought to examine the efficacy of a standardized protocol of plasma exchange (PLEX) and IVIG in decreasing donor-specific antibodies (DSAs) and improving AMR in lung transplant recipients. A retrospective chart review was conducted on all lung transplant recipients who completed a course of PLEX per UT Southwestern AMR protocol between January 2012 and December 2019 for diagnosis of AMR. Data were collected on the patient clinical course, treatment regimen, pre-PLEX DSA, post-PLEX DSA, follow-up (> 1-month post-PLEX) DSA, and pre-and post-PLEX biopsy, when available. Of 527 patients who underwent lung transplantation during the study period, 56 (11%) received an acute course of PLEX every other day per protocol for AMR of lung transplant. Forty (71%) of 56 patients had one episode of AMR requiring PLEX; 16 patients (29%) had repeat episodes of AMR within 6 weeks to 47 months of the first episode. Most patients showed improvement in AMR on biopsy (69%) and a decline in DSA (68%). Our data suggest that treatment with combined PLEX and IVIG protocol appears effective for treating lung AMR.

Predictors of self-care in kidney transplant patients according to preoperative dialysis: A comparative study

BackgroundPreemptive kidney transplantation (PKT) is associated with reduced dialysis-related morbidity and improved graft survival, which has led to an increase in the prevalence of PKT. The distinct clinical pathways of PKT and non-preemptive kidney transplantation (NPKT) patients may affect their ability to perform self-care, a key factor in post-transplant recovery. However, there is ongoing controversy regarding which group demonstrates better self-care abilities, highlighting the need to explore the factors influencing self-care in each group. ObjectivesThis study aims to identify and compare predictors of self-care in PKT and NPKT groups. MethodsWe collected data from 209 KT recipients, consisting of 101 PKT and 108 NPKT patients, using self-administered questionnaires. These questionnaires assessed general and disease-specific characteristics, stress, social support, and self-care behaviors. Data were analyzed using descriptive statistics, t-tests, ANOVA, and multiple regression analysis. ResultsThe study identified significant predictors of self-care among both PKT and NPKT patients. For PKT patients, marital status (β =.19, p=.033) and family support (β =.28, p=.006) are key predictors of self-care, with those having spousal support and strong family networks reporting better self-care levels. Conversely, in NPKT patients, significant predictors of self-care included marital status (β =.31, p=.001), employment status (β =.29, p=.007), post-transplantation duration (less than 36 month) (β =.-.22, p=.015), post-transplantation duration (36-72 month) (β =.-.33, p=.001), and stress levels (β =-.20, p=.028). ConclusionsThe study provides valuable insights into the predictors of self-care based on preoperative dialysis status, illustrating distinct predictors between the growing population of PKT and NPKT patients. These findings emphasize the need for personalized nursing strategies to enhance post-transplant self-care, tailored to individual patient characteristics.

Evaluating the Role of Hyperbaric Oxygen Therapy in Enhancing Skin Graft Outcomes: Mechanisms, Clinical Evidence, and Comparative Efficacy

Skin grafting is a critical procedure for treating skin defects from burns, trauma, and surgical interventions, yet complications such as ischemia, necrosis, and infection can limit graft success. Hyperbaric Oxygen Therapy (HBOT) has emerged as a promising adjunctive treatment that enhances skin graft viability through mechanisms including enhanced oxygenation, angiogenesis, reduced inflammation, and anti-infective effects. This review synthesizes findings from clinical studies, comparative analyses, and case reports to clarify HBOT’s efficacy in improving skin graft outcomes. Methods include a comprehensive analysis of HBOT’s impact on graft take rates, healing times, and complication rates. Results indicate that HBOT significantly improves graft survival by mitigating ischemia and infection, while comparative studies show a reduction in major amputations and improved healing in complex cases, such as diabetic foot ulcers and traumatic injuries. These findings suggest that HBOT can serve as a valuable adjunct to standard grafting procedures, offering a multifaceted approach to improve graft viability, especially in high-risk cases. This review highlights HBOT’s potential for integration into wound management protocols, providing a foundation for further exploration into its efficacy and applications in reconstructive surgery.

Graft Loss in Pediatric and Young Adult Kidney Transplantation in New Zealand: Who Is at Greatest Risk and When?

Much is reported regarding the detrimental effect of transfer to adult services for adolescent and young adult (AYA) kidney transplant (KT) recipients. However, AYA recipient age independent of time post-KT, and not relating to transfer of care, is also a strong predictor of graft loss. We assessed KT graft survival if experiencing solely pediatric (PO) or adult services (AO) versus transfer from pediatric to adult services (PTA). A retrospective cohort analysis of all first kidney transplant recipients between birth-24 years of age, from 2000 to 2019 in New Zealand. Participant identification and data were obtained via the Australia and New Zealand Dialysis and Transplantation registry. Primary outcome was graft survival stratified by service type. Cox proportional hazard modeling assessed independent risk factors of graft loss. Two hundred forty-four children and AYA with a median follow-up of 7.3 years were included. Graft survival stratified by service provision group was not different. The incidence rate of graft loss was 37, 34, and 45 per 1000 persons per year for PO, PTA, and AO respectively. Crude age-specific graft failure rates were highest for 22-24-year-olds with inferior outcomes starting from age 16, peaking at 24 years. Older adolescence and young adulthood reflect a high-risk period for KT loss. Transfer to adult services was not associated with worse graft survival compared to those experiencing either AO or PO alone. Improved models of care are needed to improve graft survival in this vulnerable population within New Zealand.

NK Cells: Not Just Followers But Also Initiators of Chronic Vascular Rejection.

Chronic graft rejection represents a significant threat to long-term graft survival. Early diagnosis, understanding of the immunological mechanisms and appropriate therapeutic management are essential to improve graft survival and quality of life for transplant patients. Knowing which immune cells are responsible for chronic vascular rejection would allow us to provide effective and appropriate treatment for these patients. It is now widely accepted that natural killer (NK) cells play an important role in chronic vascular rejection. They can either initiate chronic vascular rejection by recognizing missing self on the graft or be recruited by donor-specific antibodies to destroy the graft during antibody-mediated rejection. Whatever the mechanisms of activation of NK cells, they need to be primed to become fully activated and damaging to the graft. A better understanding of the signaling pathways involved in NK cell priming and activation would pave the way for the development of new therapeutic strategies to cure chronic vascular rejection. This review examines the critical role of NK cells in the complex context of chronic vascular rejection.

Defining the Etiology of Renal Allograft Dysfunction Using Banff 2019 Classification: Correlation with Post-Transplant Duration and Creatinine Levels-A Comprehensive Analysis of 200 Renal Biopsies at a Tertiary Care Medical Center Hospital.

Chronic kidney disease is a growing global health issue, contributing significantly to morbidity and mortality. The incidence of end-stage renal disease (ESRD) is approximately 100 per million population. Renal transplantation remains the cornerstone treatment for ESRD, with a projected 20-year survival rate of 60%. We aim to define the etiology of renal allograft dysfunction using the Banff 2019 classification by analyzing 200 renal allograft biopsies in correlation with creatinine levels across post-transplant time frames. 200 renal allograft biopsies are analyzed using the recent Banff 2019 classification with creatinine levels and post-transplant duration correlation. The study included 150 (75%) male patients and 50 (25%) female patients, with the majority 78 (39%) representing the age group of 16-30 years. 36 (18%) biopsies were within 3-month post-transplant, while 92 (46%) were 2-year post-transplant. According to the Banff 2019 classification, 92 (46.0%) transplant rejection biopsies were identified, with most 54 (27%) exhibiting antibody-mediated rejection (Category 2), including 40 (20%) active acute antibody-mediated rejection (ABMR) and 14 (7.0%) chronic active ABMR. T-cell-mediated rejection (TCMR; Category 4) represented 12 (6%) biopsies, including 10 (5%) acute TCMR and 2 (1%) chronic active TCMR. Category 5, the miscellaneous group, represented 100 (50%) biopsies, out of which 32 (16%) exhibited calcineurin inhibitor (CNI) toxicity, 38 (19%) acute tubular necrosis, and 8 (4%) thrombotic microangiopathy. A notable variation in the dysfunction distribution across different post-transplant time frames indicated a temporal evolution in the underlying causes of allograft dysfunction. Specific Banff categories showed a robust association with renal dysfunction, potentially contributing to the elevation of creatinine levels and renal function deterioration. Our study highlights the intricate pathophysiology of renal allograft dysfunction. Most biopsies were attributed to ABMR whereas one-third of biopsies exhibited mixed lesions (ABMR and TCMR or ABMR and calcineurin inhibitor toxicity (CNIT)). Additionally, this study suggests that renal allograft rejection remains a significant contributor to graft dysfunction. A complex interplay between histological findings, Banff classification, and renal function is noted. A significant difference in the distribution of dysfunction across post-transplant time frames is noted suggesting a temporal evolution in the etiology of allograft dysfunction. Certain Banff categories demonstrate a stronger association with renal dysfunction that may influence creatinine level increase and renal function deterioration. In correspondence to the recent Banff 2019 guidelines for diagnosing ABMR, we emphasize the role of C4d staining on immunofluorescence or immunohistochemistry in allograft biopsies as imperative for timely diagnosis and immunosuppressant therapy adjustment, ultimately enhancing graft survival. Further research is needed to elucidate the underlying mechanisms driving renal dysfunction in different Banff categories, ultimately informing personalized management strategies for patients with renal allograft dysfunction. In line with the Banff 2019 guidelines for diagnosing ABMR, this study highlights the critical role of C4d staining through immunofluorescence or immunohistochemistry in allograft biopsies for early diagnosis and timely adjustment of immunosuppressive therapy, ultimately improving graft survival.

A Novel Laboratory-Based Strategy for Single Adipocyte and Adipose-Derived Stem Cells Extraction for Transplantation: An Experimental Research.

Autologous fat grafting is widely used in plastic surgery. However, its main limitation is the low survival rate of fat grafts after transplantation. Transplantation of single adipocytes in combination with adipose-derived stem cells (ADSCs) could largely preserve the activity of the fat and improve graft survival. To verify the long-term survival rate of single adipocyte graft in vivo and its viable fat morphology for future fat grafting. Healthy adipose tissue was harvested and disassociated using fat dissociation solution, the Single-cell Suspension Preparation System (SSPS) was used to obtain a mixture of single adipocytes, ADSCs and stromal vascular fraction (SVF), and the structure of single adipocytes was verified by cell mask red and DAPI double staining. Nine male Balb/c nude mice were used, and three different graft volumes were established (0.05, 0.1 and 0.2ml). For each mouse, four sites were selected for transplantation, one for macrofat and the other three for single adipocytes, and different transplant volumes 30, 60 and 90days after transplantation. In each period, 3mice were selected to measure the volume of fat graft. Double staining with cell mask red and DAPI confirmed that the nucleus was identified intracellularly, which also indicated that the adipocytes in the single-cell suspension were structurally complete. When evaluating the transplantation, the groups with a volume of 0.05 ml and 0.2ml performed better in the single-cell fat group in all transplantation periods, the group with a volume of 0.1ml performed better in the single-cell group in the 30- and 60-day transplantation, and the differences were significant (P<0.05). In this study, the SSPS was used to obtain a new transplant material containing single adipocytes and ADSCs by enzymatic hydrolysis of adipose tissue and converted into single cells. It effectively improved the survival rate of fat grafting and the long-term effect of transplantation. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Improved graft survival by using three-dimensional printing of intra-abdominal cavity to prevent large-for-size syndrome in liver transplantation.

While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient's abdomen in patients with small body size between July 2020 and February 2022. Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

Suppressive Role of Pigment Epithelium-derived Factor in a Rat Model of Corneal Allograft Rejection.

Immunological rejection is the most common reason for corneal transplantation failure. The importance of T cells in corneal allograft rejection is well demonstrated. Recent studies highlight that pigment epithelium-derived factor (PEDF) plays an immunoregulatory role in ocular diseases by enhancing the suppressive phenotype of regulatory T cells besides its other functions in neurotrophy and antiangiogenesis. The effects of PEDF on immune rejection were examined in rat models of corneal transplantation using slit-lamp microscope observation, immunohistochemistry, flow cytometry, and Western blot. In vitro, we demonstrated PEDF reduced alloreactive T-cell activation using real-time polymerase chain reaction, flow cytometry, and Western blot. Topical administration of PEDF provided corneal transplantation rats with an improved graft survival rate of corneal allografts, reduced hemangiogenesis, and infiltration of immune cells in corneas, in particular, type 17 T helper cells while increased regulatory T cells. Moreover, nerve reinnervation within grafts was promoted in PEDF-treated recipient rats. In vitro, PEDF inhibited alloreactive T-cell activation via the c-Jun N-terminal kinase/c-Jun signaling pathway and upregulated the expressions of interleukin-10 and transforming growth factor-β, emphasizing the suppressive role of PEDF on immune responses. Our results underscore the feasibility of PEDF in alleviating corneal allograft rejection and further illustrate its potential in managing immune-related diseases.

Highly Sensitized Kidney Transplant Outcomes After the 2014 Kidney Allocation System Change.

Introduction: Kidney Allocation System (KAS) was implemented by United Network for Organ Sharing in 2014 to reduce allocation disparities. Research Questions: Outcomes of highly sensitized patients (calculated panel reactive antibody (cPRA) ≥ 97%) before and after KAS were compared to low-risk recipients (cPRA <10%) in the post-KAS era were examined. The impact on racial disparities was determined. Design: This was a retrospective study of national registry data. Two cohorts of adult candidates waitlisted for deceased donor transplantation during 3-year periods before and after KAS were identified. Results: Highly sensitized patients (N = 1238 and 4687) received a deceased donor kidney transplant between January 1, 2011 and December 31, 2013 and between January 1, 2015 and December, 31, 2017. Racial disparity for highly sensitized patients improved, yet remained significant (P < 0.001), with Black patients comprising 40% and 41% of the highly sensitized candidates and 28% and 34% of the recipients pre- and post-KAS. While posttransplant death-censored graft failure for highly sensitized recipients was similar overall, post-KAS was associated with improved graft survival in the first year after transplant (HR 0.56, 95% CI 0.40-0.78). When compared to contemporaneous lowrisk recipients, both death-censored and all-cause graft failure were similar for highly sensitized recipients and was associated with increased risk for death-censored graft failure beyond the first year (HR 1.39, 95% CI 1.11-1.73). Conclusion: The allocation system led to an increase in transplantation in highly sensitized candidates without compromising outcomes. Although KAS has led to more balanced transplant rates between highly sensitized Black and White patients, racial inequalities persist.

Platelet-Rich Plasma in Aesthetic Dermatology: Current Evidence and Future Directions.

Platelet-rich plasma (PRP) has emerged as a promising treatment in aesthetic dermatology. This systematic review aims to evaluate the current evidence for PRP applications in skin rejuvenation, hair restoration, wound healing, and fat grafting. FollowingPreferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive literature search was conducted across multiple databases and 13 studies meeting the inclusion criteria were selected for review. The Mixed Methods Appraisal Tool (MMAT) was used to assess the quality of included studies. The reviewed studies consistently reported positive outcomes for PRP across various applications. In skin rejuvenation, significant improvements in collagen density and overall skin appearance were observed. For hair restoration, studies showed mean increases of 18-27.7 hairs/cm² in treated areas. PRP demonstrated efficacy in accelerating wound healing across various wound types, including chronic ulcers. In fat grafting, PRP was associated with improved graft survival and integration. Patient satisfaction was generally high across all applications. However, there was significant heterogeneity in PRP preparation methods and treatment protocols among studies. This systematic review provides evidence supporting the efficacy of PRP in aesthetic dermatology, particularly in skin rejuvenation, hair restoration, wound healing, and fat grafting. PRP demonstrates a favorable safety profile across applications. However, the variability in study designs and PRP protocols highlights the need for standardization. Future research should focus on large-scale randomized controlled trials with standardized protocols and longer follow-up periods to solidify the evidence base for PRP in aesthetic dermatology.

Trained immunity suppression determines kidney allograft survival

The innate immune system plays an essential role in regulating the immune responses to kidney transplantation, but the mechanisms through which innate immune cells influence long-term graft survival are unclear. The current study highlights the vital role of trained immunity in kidney allograft survival. Trained immunity describes the epigenetic and metabolic changes that innate immune cells undergo following an initial stimulus, allowing them have a stronger inflammatory response to subsequent stimuli. We stimulated healthy peripheral blood mononuclear cells with pretransplant and posttransplant serum of kidney transplant patients and immunosuppressive drugs in an in vitro trained immunity assay and measured tumor necrosis factor and interleukin 6 cytokine levels in the supernatant as a readout for trained immunity. We show that the serum of kidney transplant recipients collected 1 week after transplantation can suppress trained immunity. Importantly, we found that kidney transplant recipients whose serum most strongly suppressed trained immunity rarely experienced graft loss. This suppressive effect of posttransplant serum is likely mediated by previously unreported effects of immunosuppressive drugs. Our findings provide mechanistic insights into the role of innate immunity in kidney allograft survival, uncovering trained immunity as a potential therapeutic target for improving graft survival.

Orchestrating the Impact of KIR/HLA Interactions on Kidney Transplant.

This study examines the interplay between human leukocyte antigen (HLA) compatibility and killer-cell immunoglobulin-like receptor (KIR) genotypes in influencing kidney transplantation outcomes. Understanding these interactions is crucial for improving graft survival and minimizing rejection risks. We evaluated 84 kidney transplant recipients, dividing them into two groups based on post-transplant outcomes: there were 68 with stable graft function (SGF) and 16 who experienced chronic rejection (CR). Patients were selected based on specific inclusion criteria. HLA mismatches (Class I: HLA-A, -B; Class II: HLA-DR) and KIR genotypes were determined using standard genotyping techniques. Statistical analyses, including logistic regression, were performed to correlate these factors with transplant outcomes. Significant age differences were observed, with younger patients more likely to experience graft rejection, while no significant gender-based differences were noted. A significant correlation was found between Class II mismatches and increased rejection rates, highlighting the importance of HLA-DR compatibility. Further analysis revealed that certain inhibitory KIRs, such as KIR3DL1, were associated with favorable outcomes, suggesting a protective role against graft rejection. These findings were corroborated by evaluating serum creatinine levels over multiple years, serving as a biomarker for renal function post transplant. This study underscores the critical need for meticulous HLA matching and the consideration of KIR genotypes in pre-transplant evaluations to enhance graft survival and minimize rejection risks. Integrating these genetic factors into routine clinical assessments could significantly improve personalized transplant medicine strategies, ultimately enhancing patient outcomes. Further research is needed to explore the underlying mechanisms and validate these findings in larger, diverse populations.

Future directions for xenotransplantation in lungs.

Advancements in preclinical xenotransplant studies have opened doors for clinical heart and kidney xenotransplantation. This review assesses recent progress in lung xenotransplantation research and its potential clinical implications. The efficacy of the humanized von Willebrand factor in reducing platelet sequestration in ex-vivo and in-vivo lung xenotransplant models was showcased. Combining human tissue factor pathway inhibitor and CD47 expression with selectin and integrin inhibition delayed neutrophil and platelet sequestration. Enhanced expression of human complement regulatory proteins and thrombomodulin in genetically engineered pig lungs improved graft survival by reducing platelet activation and modulating coagulation disruptions. Knocking out the CMAH gene decreased antibody-mediated inflammation and coagulation activation, enhancing compatibility for human transplantation. Furthermore, CMAH gene knockout in pigs attenuated sialoadhesin-dependent binding of human erythrocytes to porcine macrophages, mitigating erythrocyte sequestration and anemia. Meanwhile, in-vivo experiments demonstrated extended survival of xenografts for up to 31 days with multiple genetic modifications and comprehensive treatment strategies. Experiments have uncovered vital insights for successful xenotransplantation, driving further research into immunosuppressive therapy and genetically modified pigs. This will ultimately pave the way for clinical trials designed to improve outcomes for patients with end-stage lung disease.

The Spread Pattern of New Practice in Liver Transplantation in the United States.

Introducing new liver transplantation (LT) practices, like unconventional donor use, incurs higher costs, making evaluation of their prognostic justification crucial. This study reexamines the spread pattern of new LT practices and its prognosis across the United States. The study investigated the spread pattern of new practices using the UNOS database (2014-2023). Practices included LT for hepatitis B/C (HBV/HCV) nonviremic recipients with viremic donors, LT for COVID-19-positive recipients, and LT using onsite machine perfusion (OMP). One year post-LT patient and graft survival were also evaluated. LTs using HBV/HCV donors were common in the East, while LTs for COVID-19 recipients and those using OMP started predominantly in California, Arizona, Texas, and the Northeast. K-means cluster analysis identified three adoption groups: facilities with rapid, slow, and minimal adoption rates. Rapid adoption occurred mainly in high-volume centers, followed by a gradual increase in middle-volume centers, with little increase in low-volume centers. The current spread patterns did not significantly affect patient survival. Specifically, for LTs with HCV donors or COVID-19 recipients, patient and graft survivals in the rapid-increasing group was comparable to others. In LTs involving OMP, the rapid- or slow-increasing groups tended to have better patient survival (p=0.05) and significantly improved graft survival rates (p=0.02). Facilities adopting new practices often overlap across different practices. Our analysis revealed three distinct adoption groups across all practices, correlating the adoption aggressiveness with LT volume in centers. Aggressive adoption of new practices did not compromise patient and graft survivals, supporting the current strategy. Understanding historical trends could predict the rise in future LT cases with new practices, aiding in resource distribution.

Sensitive HLA antibody testing and the risk of antibody-mediated rejection and graft failure.

Solid phase detection and identification of HLA antibodies in kidney transplantation currently relies on single antigen bead (Luminex®) assays, which is more sensitive than the previously used enzyme-linked immunosorbent assays (ELISA). To evaluate the impact of more sensitive HLA testing on antibody-mediated rejection (AMR) occurrence and allograft survival, we analysed 1818 renal allograft recipients transplanted between March 2004 and May 2021. In 2008, solid phase testing switched from ELISA to Luminex. We included 393 (21.6%) transplantations before and 1425 (78.4%) transplantations after transition from ELISA- to Luminex-based testing. For this study, bio-banked ELISA era samples were tested retrospectively with Luminex. Significantly less pretransplant DSA were found in patients transplanted with pre-existing HLA antibodies in the Luminex (109/387) versus the ELISA period (43/90) (28% vs. 48%, p < 0.01). Throughout histological follow-up, 169 of 1818 (9.3%) patients developed AMR. After implementing Luminex-based testing, the rate of AMR significantly decreased (p = 0.003). However, incidence of graft failure did not significantly differ between both eras. In conclusion, less patients with pretransplant DSA were transplanted since the implementation of Luminex HLA testing. Transition from ELISA- to Luminex-based HLA testing was associated with a significant decrease in AMR occurrence post-transplantation. Since the decline of AMR did not translate into improved graft survival, Luminex-based testing has the added value of preventing low-risk AMR cases. Therefore, Luminex' high sensitivity must be balanced against waiting time for a suitable organ.

Donor Inhalation of Nebulized Dexmedetomidine Alleviates Ischemia-Reperfusion Injury in Rat Lung Transplantation

Introduction: The occurrence of lung ischemia-reperfusion injury (LIRI) after lung transplantation results in primary graft dysfunction (PGD) in more than 50% of cases, which seriously affects the prognosis of recipients. Currently, donor lung protection is the focus of research on improving graft survival in lung transplant recipients. Dexmedetomidine (Dex) is a widely used general anesthesia adjuvant in clinical practice to alleviate ischemia-reperfusion injury in the lungs, liver, heart, kidneys, and brain. However, intravenous infusion of Dex can cause negative effects on the cardiovascular system. Inhaling nebulized Dex can directly act on the alveolar tissue and alleviate its cardiovascular inhibitory effect by reducing drug intake. This study aimed to investigate the effect of donor nebulized Dex inhalation on LIRI after lung transplantation in rats. Methods: We randomly divided the male Sprague-Dawley rats into donor rats and recipient rats, and allowed the donor rats to inhale nebulized Dex or physiological saline 15 min before surgery. The donor lung was refrigerated for 8 h before each single-lung transplant. After 2 h of reperfusion of the transplanted lung, serum and transplanted lung tissue were collected. The wet-to-dry weight ratio of the lung tissue was measured, arterial blood gas was detected, and histopathology changes, oxidative stress, inflammatory reactions, and apoptosis were evaluated. Results: Pretransplant inhalation of Dex through the donor’s lung reduced the injury of the transplanted lung, increased the levels of malondialdehyde and myeloperoxidase, and decreased the levels of superoxide dismutase and glutathione in the lung tissue. Moreover, nebulized Dex inhalation of the donor lung inhibited LIRI-induced tumor necrosis factor-α, interleukin-6, and inducible nitric oxide synthase expression and also suppressed nuclear factor kappa B phosphorylation. Nebulized Dex inhalation reduced the rate of cell apoptosis in the transplanted lung tissue by inhibiting the upregulation of Bax, downregulation of Bcl-2, and increase in caspase-3 lysis caused by LIRI. Conclusion: Inhalation of atomized Dex is a potential donor lung protection strategy, which can be used to reduce LIRI after lung transplantation and may be helpful to improve the occurrence of PGD and prognosis of lung transplant recipients.