Transplant Rejection Research Articles

Ultrasound-targeted sirolimus-loaded microbubbles improves acute rejection of heart transplantation in rats by inhibiting TGF-β1-Smad signaling pathway, promoting autophagy and reducing inflammation

Acute rejection (AR) remains a pivotal complication and leading cause of mortality within the first year following heart transplantation (HT). In this study, we assessed the impact of ultrasound-targeted microbubbles loaded with sirolimus (SIR-MBs) on AR in a rat HT model and delved into the underlying mechanisms. We established a rat abdominal ectopic HT model, which was stratified into three groups receiveing the PBS, SIR-MBs + ultrasound-targeted microbubble destruction (UTMD), and sirolimus, respectively. The protective effects of each treatments on survival rate, inflammatory response, autophagy and TGF-β1-Smad signaling pathway-related proteins were evaluted. Additionally, rescue experiment was performed via adding the autophagy inhibitor or TGF-β1 agonist in combination therapy. UTMD combined SIR-MBs mediated 15-fold higher local drug concentration compared to direct sirolimus administration. The infiltration of inflammatory cells in the transplanted hearts indicated that SIR-MBs combined with UTMD were effective in mitigating the inflammatory response, achieving levels significantly lower than those observed in the sirolimus group. Furthermore, after SIR-MBs combined with UTMD treatment, the expression levels of TGF-β1-Smad signaling pathway-related proteins in heart tissues also showed a significant decrease compared to the model control group. Conversely, the expressions of autophagy proteins LC3-II, Beclin-1 and β-arrestin showed an up-regulated trend. Rescue experiments also revealed that the enhancement in survival trends was markedly suppressed following the administration of CsA or SRI-011381, respectively. Collectively, our findings suggest that SIR-MBs combined with UTMD augment the local treatment efficacy for AR in rat HT models by inhibiting the TGF-β1-Smad signaling pathway, promoting autophagy, and alleviating inflammation.

Correction to: Effect of CXCR3/HO-1 genes modified bone marrow mesenchymal stem cells on small bowel transplant rejection

Correction to “Effect of CXCR3/HO-1 genes modified bone marrow mesenchymal stem cells on small bowel transplant rejection. World J Gastroenterol 2017 June 14; 23 (22): 4016-4038”. In this article, there is a picture that needs to be corrected.

Blood Gene Expression Profiling and Donor-derived Cell-free DNA to Noninvasively Diagnose Clinical and Subclinical Kidney Transplant Rejection: A Real-life Appraisal Study

Background. Peripheral blood biomarkers aim to noninvasively diagnose kidney allograft rejection, but most lack robust independent validation. TruGraf is intended to exclude subclinical cellular rejection (TCMR), whereas donor-derived cell-free DNA Viracor-TRAC has proven value in excluding antibody-mediated rejection (AMR). We aim to validate both biomarkers for accurate rejection diagnosis in a real-world clinical setting. Methods. We prospectively included 230 unselected, consecutive kidney transplants from 6 centers undergoing for-cause and protocol biopsies with paired blood samples from December 2021 to 2022. TruGraf and Viracor-TRAC were blindly run by a central laboratory. Results. The incidence of rejection was 22.6% (17.3% surveillance; 27% for-cause biopsies). Inflammation was associated with higher TRAC levels, with AMR/mixed and microvascular inflammation (MVI) showing the highest levels (P < 0.05). TruGraf did not associate with any specific allograft injury. No biomarkers, individually or combined, accurately diagnosed any rejection (area under the receiver operating characteristic curve [AUROC] < 0.65). However, high TRAC levels, when combined with DSA in for-cause biopsies, predicted AMR/mixed rejection or MVI (AUROC = 0.817; P < 0.001), outperforming serum creatinine and DSA (AUROC < 0.65). Conclusions. In this large, prospective, observational real-life study, we were unable to validate TruGraf and TRAC to diagnose rejection but found a useful context of use for TRAC to noninvasively diagnose AMR/mixed or MVI in conjunction with DSA in dysfunctioning graft.

A review of cell-free DNA and epigenetics for non-invasive diagnosis in solid organ transplantation

IntroductionCirculating cell-free DNA (cfDNA) is emerging as a non-invasive biomarker in solid organ transplantation (SOT) monitoring and data on its diagnostic potential have been increasing in recent years. This review aims to summarize the main advances in technologies, clinical applications and future perspectives of cfDNA for transplantation, and to approach the contribution of epigenetics to improve the specific detection of rejection.MethodsPublished literature investigating cfDNA as a biomarker for the diagnosis of transplant rejection was systematically reviewed, specifically clinical trials evaluating the test performance of algorithms predicting rejection based on cfDNA fraction. Literature highlighting epigenetic features in transplant rejection was also reviewed to outline the potential contribution of the epigenomic analysis to the needs of rejection-specific diagnosis.Results40 articles were reviewed, and results were extracted and summarized. 16 met the inclusion criteria by evaluating the diagnostic performance of a predictive test for the discrimination of rejection vs. non-rejection patients (2 heart, 3 liver, 4 kidney, and 7 lung transplantations). The recurring conclusion is the kinetics of dd-cfDNA levels, strongly increasing immediately after transplantation and reaching basal levels after days to weeks and remaining stable in non-rejection patients. On the other hand, rejection is characterized by an increase in dd-cfDNA levels, depending on the transplanted organs. In addition, the epigenetic signature can help improve the specificity of the diagnosis of rejection by searching for specific epigenetic features that are by the clinical status of patients.ConclusionCell-free DNA is a promising non-invasive biomarker but still needs standardization of technologies and protocols to be used for diagnostic purposes. Moreover, the lack of specificity of this marker can be compensated by the contribution of epigenetic analysis for which data are growing, although progress is still needed for its use in a clinical context.

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.

Global left ventricular relaxation index in predicting cardiac cellular rejection in paediatric heart transplant patients.

Endomyocardial biopsy remains the gold standard for cardiac cellular rejection surveillance after heart transplantation. We studied a novel non-invasive index of left ventricular relaxation to detect cardiac cellular rejection in paediatric heart transplant patients. This is a single-centre retrospective study of paediatric heart transplant patients who underwent endomyocardial biopsy from June 2014 to September 2021. Left ventricular relaxation index was calculated as the sum of diastolic tissue Doppler imaging velocities (E) of the left ventricular lateral, septal, and posterior walls divided by the percentage of the left ventricular posterior wall thinning by M-mode. Statistical analysis included t-tests and Mann-Whitney tests to compare means and medians between treatment and non-treatment groups. We used the cut-off with the maximum Youden index to compare the sensitivity and specificity of left ventricular relaxation index to detect rejection. The study included 65 patients who underwent 246 cardiac catheterizations and endomyocardial biopsies. Out of 246, 192 procedures were included and 54 were excluded due to recent transplants or lack of echocardiographic data. A total of 114 demonstrated Grade 0R, 68 Grade 1R, 8 Grade 2R, and 2 Grade 3R allograft rejection. The difference in mean left ventricular relaxation index between treatment versus non-treatment groups (2R, 3R vs. 0R, 1R) was not statistically significant (p = 0.917). A left ventricular relaxation index cut-off of 0.73 had the highest Youden index with good sensitivity (100%) and poor specificity (23%) for detecting rejections with grades 2R and 3R. Left ventricular relaxation index, a novel index of left ventricular relaxation, was not a sensitive or specific predictor of cardiac cellular rejection in paediatric heart transplants.

Prescription Patterns of Mycophenolate Mofetil in a Group of Patients from Colombia

Background: Mycophenolate mofetil is used for the prevention of solid organ transplant rejection and for other indications, such as systemic lupus erythematosus (SLE). Objective: To determine the prescription patterns of mycophenolate mofetil in a group of Colombian patients. Methods: This was a cross-sectional study of patients receiving mycophenolate mofetil between 2021 and 2022. The data were obtained from a drug dispensing database. Sociodemographic, clinical (diagnostic), and pharmacological variables were identified. Results: A total of 979 patients who underwent treatment were identified; their mean age was 45.9 ± 17.1 years, and 87.4% were women. The main diagnosis associated with the use of mycophenolate mofetil was SLE (39.1%), followed by other rheumatic diseases (8.5%), nephrotic syndrome (7.5%), and solid organ transplantation (6.4%). The relationship between the mean dose and the defined daily dose was 0.75. Ten percent of patients received mycophenolate alone, whereas 32.9% received mycophenolate in combination therapy with conventional disease-modifying antirheumatic drugs and glucocorticoids. A total of 76.2% had polypharmacy (five or more drugs). Conclusions: Mycophenolate mofetil is used mainly in combination therapy for patients with SLE and other rheumatological diseases and for solid organ transplants at doses lower than those recommended.

Longitudinal Assessment of T1 Mapping Trends Disease in Pediatric Patients With Heart Transplant.

Surveillance for heart transplant rejection by endomyocardial biopsy is invasive and may yield false negatives. T1 and T2 mapping from cardiac magnetic resonance can demonstrate elevations with rejection. We sought to evaluate longitudinal changes in T1 and T2 mapping in pediatric patients with heart transplant. A cohort study was performed of pediatric patients with heart transplant who underwent concurrent endomyocardial biopsy and cardiac magnetic resonance with T1 and T2 mapping from December 2019 to July 2024. Segmental values were measured and subsegmental elevations (ie, hotspots) were identified. Subjects were categorized as either treated rejection or no rejection. Peak and mean T1 and T2 values and number of hotspots at/between each time point for patient dyads were compared between the groups. A total of 21 subjects (7 treated rejection, 14 no rejection) with 68 total encounters met inclusion criteria. Peak and mean T1 values were higher in treated rejection patients during the rejection period and decreased with treatment (peak, 1086 versus 1052; mean, 1028 versus 1021), such that at last follow-up when their rejection had resolved, there was no significant difference in values when compared with no rejection patients (peak, 1066; mean, 1016). The number of T1 hotspots decreased after rejection treatment (2 versus 1). There were no changes in peak or mean T2 values in the treated rejection group despite treatment, and peak and mean T2 values were similar to patients with no rejection through last follow-up. Elevated T1 values and hotspots observed during cardiac allograft rejection decline in response to treatment. Cardiac magnetic resonance may serve as a noninvasive monitoring tool for the development and resolution of rejection, as well as the effectiveness of rejection therapy.

Proposing Novel Biological Scaffolds for the Regeneration of the Dura Mater

ABSTRACTThe dura mater protects underlying tissues and cerebrospinal fluid, but dural abnormalities can cause leaking and meningitis and wound infections. This review emphasizes the relevance of dural repair and the progress of dural reconstruction materials, focusing on biological scaffolds. A comprehensive assessment of dural substitution literature focused on composite, acellular, natural, synthetic, and homologous materials. Decellularized dura scaffolds as viable natural biomaterials for tissue engineering are explored in this overview of these materials' properties, effectiveness, and therapeutic uses. The evaluation also compares materials and assesses host tissue response in preclinical and clinical studies. The review highlights various dural substitution findings. There is no gold standard for dural repair, despite the variety of materials used. Replicating natural dura mater's mechanical and structural qualities is difficult. Recent research suggests that decellularized dura scaffolds can regenerate tissue while reducing inflammation and transplant rejection. Furthermore, the movement toward personalized medicine in this sector suggests that bespoke alternatives might be chosen depending on patient characteristics, improving treatment effects. Synthesizing dural replacement research and clinical uses in this review adds to knowledge. It tackles standard materials' shortcomings and shows how biological scaffolds might improve dural repair. The analysis opens the door to personalized dural repair research that might enhance patient outcomes and advance neurosurgery. The insights presented herein highlight the intriguing prospects for appropriate dural restorative materials, seeking to improve dural defect treatment.

CAR-ving away OX40L with engineered Tregs.

OX40L-CAR-Tregs show promise for treating autoimmunity and transplantation rejection.

Spatial Transcriptomic Signatures of Early Acute T Cell-mediated Rejection in Kidney Transplants.

Kidney transplantation significantly improves the quality of life for those with end-stage renal failure, yet allograft rejection resulting from immune cell interactions remains a persistent challenge. Although T cell-directed immunosuppressive drugs effectively contain graft rejection in most patients, a notable proportion still experiences acute T cell-mediated rejection (TCMR). Despite an emphasis on suppressing T cell-mediated immune responses, successful control over TCMR is not always achieved, suggesting the potential involvement of factors beyond T cells. Biopsy samples from suspicious (borderline) for acute TCMR (borderline TCMR) and non-TCMR patients were obtained 9 d postsurgery, and spatial transcriptomics profiling was conducted using the GeoMx Digital Spatial Profiler platform. Regions of interest in the glomerulus and interstitium were selected on the basis of immunohistochemistry staining anti-CD3 to identify areas with T-lymphocyte infiltration. Differential gene expression analysis was performed using unpaired t tests. Unbiased clustering of transcriptional profiles across all regions of interest showed distinct transcriptional profiles between glomeruli and interstitium in non-TCMR samples, whereas borderline TCMR samples displayed no distinct transcriptional profiles between these regions. Contrary to the prevailing T cell-centric view, we observed pathways and genes associated with innate immunity-related inflammatory conditions expressed in glomerular regions of borderline TCMR biopsies. Immunofluorescence staining for CD68 confirmed the presence of macrophages in the glomeruli of the post-TCMR sample in a validation cohort, indicating macrophage involvement in the glomerular response after TCMR. Activation of the innate immune response in borderline TCMR appears to impact not only the interstitium but also the glomerulus. Glomerulus-specific immune signatures suggest the role of the innate immune system in rejection. This nuanced understanding proposes the necessity for tailored therapeutic interventions targeting both innate and adaptive immune pathways to enhance transplant outcomes.

Safety and tolerability of tegoprubart in patients with amyotrophic lateral sclerosis: A Phase 2A clinical trial.

The interaction of CD40L and its receptor CD40 on activated T cells and B cells respectively control pro-inflammatory activation in the pathophysiology of autoimmunity and transplant rejection. Previous studies have implicated signaling pathways involving CD40L (interchangeably referred to as CD154), as well as adaptive and innate immune cell activation, in the induction of neuroinflammation in neurodegenerative diseases. This study aimed to assess the safety, tolerability, and impact on pro-inflammatory biomarker profiles of an anti CD40L antibody, tegoprubart, in individuals with amyotrophic lateral sclerosis (ALS). In this multicenter dose-escalating open-label Phase 2A study, 54 participants with a diagnosis of ALS received 6 infusions of tegoprubart administered intravenously every 2 weeks. The study was comprised of 4 dose cohorts: 1 mg/kg, 2 mg/kg, 4 mg/kg, and 8 mg/kg. The primary endpoint of the study was safety and tolerability. Exploratory endpoints assessed the pharmacokinetics of tegoprubart as well as anti-drug antibody (ADA) responses, changes in disease progression utilizing the Revised ALS Functional Rating Scale (ALSFRS-R), CD154 target engagement, changes in pro-inflammatory biomarkers, and neurofilament light chain (NFL). Seventy subjects were screened, and 54 subjects were enrolled in the study. Forty-nine of 54 subjects completed the study (90.7%) receiving all 6 infusions of tegoprubart and completing their final follow-up visit. The most common treatment emergent adverse events (TEAEs) overall (>10%) were fatigue (25.9%), falls (22.2%), headaches (20.4%), and muscle spasms (11.1%). Mean tegoprubart plasma concentrations increased proportionally with increasing dose with a half-life of approximately 24 days. ADA titers were low and circulating levels of tegoprubart were as predicted for all cohorts. Tegoprubart demonstrated dose dependent target engagement associated and a reduction in 18 pro-inflammatory biomarkers in circulation. Tegoprubart appeared to be safe and well tolerated in adults with ALS demonstrating dose-dependent reduction in pro-inflammatory chemokines and cytokines associated with ALS. These results warrant further clinical studies with sufficient power and duration to assess clinical outcomes as a potential treatment for adults with ALS. Clintrials.gov ID:NCT04322149.

Heart Transplant Rejection in the Setting of Glyphosate Herbicide Exposure; A Case Report

Glyphosate is a common herbicide utilized worldwide with known exposure related toxicities. Numerous adverse effects related to glyphosate exposure have been documented, specifically in non-human models, however literature is lacking on cardiotoxic effects specific to heart transplant patients. Rejection is the most common post-transplant complication and the diagnosis of such is vital in order to guide immediate and appropriate treatment. In addition to the endomyocardial biopsy, noninvasive genetic testing can aid in rejection diagnosis and distinguish between cell-mediated and antibody-mediated rejection. We describe a case of glyphosate exposure in a post orthotopic heart transplant and the subsequent heart transplant rejection, patient’s clinical course, treatment, and follow up.

Scleral lens fitting after paediatric limbal dermoid removal

Purpose. This case report describes the management of refractive error and amblyopia using a scleral lens fitted to the eye of a young child with an irregular cornea resulting from limbal dermoid removal and corneal transplant in infancy. Material and Methods. A young infant was initially fitted with spectacles and occlusion therapy following the surgical excision of a limbal dermoid and full thickness corneal transplant. The vision did not improve in spite of patching so the child was referred for contact lens fitting. Various iterations of scleral lens fitting were carried out. Results. Scleral lens fitting was attempted from the age of 2 years but transplant rejections, the COVID-19 pandemic and variable cooperation meant that adequate lens wear could not be achieved in the early stages. In addition, the corneal shape changed during the course of the fitting. During these periods, spectacle wear and occlusion therapy were maintained until a good lens fit could be achieved following several modifications. Treatment is ongoing but at the age of 5 years, the visual acuity is 0.24 logMAR letters. Conclusion. Scleral lenses can be used to habilitate the vision in an eye with an irregular cornea but when scleral lens wear is not possible, it is important to persevere with spectacle correction and patching therapy. Several iterations of scleral lenses may be needed as the eye changes and the child grows.

Donor-derived cell-free DNA versus left ventricular global longitudinal strain in noninvasive detection of heart allograft injury

Abstract Introduction Invasive endomyocardial biopsy (EMB) is still considered the gold standard method for monitoring heart transplant (HTx) rejection. However, it is associated with potentially serious complications, and its histopathologic interpretation has high interobserver variability. Thus, noninvasive methods for surveillance of the transplanted organ remains of great interest. The noninvasive donor-derived cell-free DNA is a marker of graft injury which can indicate acute rejection, even before the histopathological diagnosis of rejection detected by EMB. The assay has a high negative predictive value for acute rejection. Left ventricular global longitudinal strain (LV GLS) is an emerging marker of subclinical myocardial injury which plays a crucial role in the evaluation of several cardiac diseases; however, its role in HTx injury has so far been poorly investigated. Purpose We aimed to investigate the efficacy of a local laboratory-run dd-cfDNA assay-based heart transplant rejection surveillance programme, and the prognostic and discriminatory performance of LV GLS for subsequent heart allograft injury. Methods HTx recipients without a history of allograft rejection requiring intensification of immunosuppressive therapy were transitioned from our EMB-based surveillance protocol to dd-cfDNA-based rejection surveillance. We assessed the percentage of dd-cfDNA to total cell-free DNA. Injury cut-off was defined by a dd-cfDNA level ≥0.20%, while the severe injury threshold was at ≥0.35%. LV ejection fraction was calculated using 2D Simpson’s method. To derive LV GLS, we analyzed apical 4-chamber, 2-chamber, and long-axis images by 2D speckle tracking echocardiography. Results A total of 244 dd-cfDNA samples were analyzed from 46 patients in fifteen runs performed monthly between October 2022 and December 2023. The dd-cfDNA fraction remained below the injury cut-off in most patients (81%). There were no missed rejection episodes. 88% of routine EMBs that would have otherwise been performed were safely avoided. Eighteen for-cause EMBs were performed based on dd-cfDNA levels suggesting injury. One EMB verified moderate cellular rejection (ISHLT grade 2R) that required steroid pulse therapy. Two EMBs proved mild cellular rejection, one EMB confirmed mild antibody-mediated rejection, while one EMB proved mixed rejection. Thirteen EMBs found no rejection. Mean LVEF was preserved (57.6%±7.6%). Mean LV GLS was -15.1%±2.5% in the whole cohort, while -15.6%±4.7% in recipients with HTx rejection on indication EMB. There was no significant correlation between dd-cfDNA and LV GLS (n=159). Conclusion The noninvasive dd-cfDNA assay is effective in ruling out acute rejection and safely decreases the necessity of invasive surveillance EMBs after HTx. LV GLS is less sensitive in comparison with the dd-cfDNA assay for detection of myocardial injury in the early stages of graft rejection in HTx recipients at low risk for rejection.

Incidence of acute cellular and antibody mediated rejection in heart transplantation from a tertiary care center

Abstract Background Heart transplant greatly increases the survival in patients with end stage heart failure. However, cardiologists and cardiothoracic surgeons face difficulty in detecting rejection at times. Post-cardiac transplant surveillance biopsy remains the gold standard for diagnosing rejection and therapeutic intervention. Purpose The objective is to report our experience of monitoring rejection by endomyocardial biopsy (EMB). Methods The index study is an ambispective one where we evaluated all the patients who underwent heart transplant at our center from 1994 to 2021. Results Heart transplant were carried out in 72 patients within a period of 28 years, with majority being done after 2016. The patients mean age was 31.6 years (10-59 years). The commonest indication was dilated cardiomyopathy (67%) followed by ischemic cardiomyopathy (2.5%), congenital heart disease (7%) and other miscellaneous causes (5%). The mean age of donors was 31.8 years (14-55 years). Eight of the 72 patients died without any post cardiac transplant endomyocardial biopsy. The remaining 64 patients underwent cumulatively a total of 271 endomyocardial biopsy procedures. Majority of endomyocaridal biopsies contained three cores (range 1-7). First EMB procedure was performed in 17 (26.6%) patients within first seven days, 35(53.1%) within the second week and 12(20.3%) after 14 days. Histologically rejection was identified in 42 (66%) patients. Thirty-nine (61%) had only acute cellular rejection (ACR), one (1.6%) had only antibody mediated rejection (AMR) and two (3.1%) had mixed ACR and AMR. These 42 patients with rejection had a total of 90 (33.2%) episodes of ACR detected in 271 endomyocardial biopsies. Out of 90 ACR, 44 (48.9%) occurred in less than six months; seventeen (18.9% of 90 ACR) episodes occurred between six and 12 months and 29 (32.2%) after one year. The mean of presentation of first ACR episode was 36 weeks (range 5 days to 3.6 years). There were 172 endomyocardial procedures within one year of transplantation of which 61 (35%) showed rejection. Ninety-nine endomyocardial procedures were performed one year of transplantation of which 29 (29%) showed rejection. Most common grade in both the time period was ACR grade 1R (International Society for Heart and Lung Transplantation (ISHLT) 2004) (72.1% in ≤1 year and 65.5% in >1 year) followed by 2R and 3R. Thirty-eight (90.4%) of 42 patients expired in less than five years since transplantation. Two (4.8%) patients survived between five to ten years post transplantation and two (4.8%) survived more than ten years. The longest cardiac transplant recipient had completed 23 years since cardiac transplant and is alive till date. Conclusions EMB being the gold standard for cardiac allograft rejection, the cardiac pathologists need to be aware of the various grades of rejection including mixed rejection.Acute cellular rejection (ISHLT 2004)

PIRCHE-II: a new tool to predict rejection in cardiac transplantation?

Abstract Aim This retrospective observational study aims to compare patients diagnosed with antibody-mediated or cell-mediated rejection with patients without episodes of rejection and study any predictors of rejection at follow-up with particular attention to PIRCHE-II scores. Materials and Methods We performed a retrospective evaluation of prospectively collected data of heart transplant patients from January 2022 to August 2023, at a single hospital. Preoperative, intraoperative and postoperative parameters are collected anonymously in our institutional database used for internal quality control. The primary endpoint was the incidence of rejection in one of three control endomyocardial biopsies. As pre-operative data, age, sex, BSA, blood group mismatch, risk such as dyslipidemia, hypertension, diabetes, peripheral vascular disease, COPD, previous cardiac surgery, PRA, ischemia time and post-operative infections. We evaluated patients at a mean follow-up of 106 (78 – 180) days. In patients who tested positive for cell-mediated or antibody-mediated rejection, the PIRCHE-II score was calculated. Results There were 45 patients with no diagnosis of rejection and they were aged 61 [50-65]; 22.2% were women, with a mean BSA of 1.87 ± 0.19. 22.2% had a blood type mismatch. They had a mean PIRCHE-II of 111.88 ± 43.6. There were 15 patients diagnosed with rejection and they were 63 years old [52 – 66]; 20.0% were women, with a mean BSA of 1.84 ± 0.23. 13.3% had a blood type mismatch. They had a mean PIRCHE-II of 113.70 ± 33.90. In multivariable analysis, the main predictors of rejection were plasma transfusions [OR 0.053, 95% CI, p=0.02], post-operative infections [OR 0.076, 95% CI, p=<0, 02] and the PIRCHE – II [OR 3.284, 95% CI, p=0.04]. The mean PIRCHE-II of patients who presented antibody-mediated or cell-mediated rejection was 113.70 ± 33.90 and that of patients who did not present any rejection was 111.88 ± 33.90; Conclusion According to the results obtained, the PIRCHE-II algorithm could be a tool in immunological risk stratification in patients undergoing cardiac transplantation. It is necessary, however, to apply PIRCHE-II to a larger number of patients and should also be considered in light of other factors such as the immunological status of the recipients, the immediate post-operative course (infections, CMV reactivation, blood component transfusions), which could constitute an immunological trigger and patient compliance in immunosuppressive therapy.Patients' featuresResuts

Inhibiting corneal transplantation rejection via lymphatic vessel ligation in a novel murine model

The lymphatic system is a crucial contributor to allograft rejection after corneal transplantation. However, no surgical procedures for the central pathway where conjunctival lymphatic vessels converge have been investigated. Therefore, we aimed to establish a murine model of lymphatic vessel ligation and evaluate its inhibitory effect on corneal allograft rejection. A tracer was used to visualise lymphatic vessels, and complications were evaluated. A surgical technique was developed to block the lymphatic vessels. Corneas from C57BL/6 mice were transplanted into BALB/c mice divided into two groups—one with and one without lymphatic vessel ligation, to evaluate their effects on allograft rejection. Graft opacity scores were evaluated for 8 weeks, and immunohistochemistry was used to quantify angiogenesis and lymphangiogenesis. 20% trypan blue used as a tracer showed clear inflow with no complications. The two sutures and cyanoacrylate glue combination demonstrated a blocking effect after 25 days and was thus used for lymphatic ligation. Three and nine out of fourteen eyes showed rejection at 8 weeks post-surgery in the lymphatic vessel ligation and control groups, respectively. Furthermore, neovascularisation and lymphangiogenesis significantly decreased in the lymphatic vessel ligation group. Overall, we present a novel therapeutic strategy for corneal transplantation.

Challenging endomyocardial biopsies' gold standard status in rejection screening: a prospective blinded study on cardiovascular magnetic resonance in heart transplant patients

Abstract Background The detection of rejection is crucial for graft survival after heart transplantation. Endomyocardial biopsies (EMBs) serve as the gold standard for rejection surveillance despite its limitations, while cardiac magnetic resonance (CMR), in conjunction with donor-derived cell-free DNA (dd-cfDNA) analysis, holds promise as a non-invasive approach. Purpose In this prospective blinded study, our aim was to evaluate feasibility of CMR for rejection screening, validating it against EMB, dd-cfDNA, and clinical status. Methods We blindly analyzed 250 studies involving CMR, EMB, dd-cfDNA, and clinical data in 58 heart transplant recipients (17 children and 41 adults). Of these 250 studies, 239 (96%) were assessed within 1 to 28 months after transplantation, and 11 studies (4%) 3-14 years post-transplant. In CMR T1- and T2-mapping analyses, acute rejection was defined by T1 or T2 times exceeding the specified thresholds (T1 ≥ 1060 ms, T2 ≥ 55 ms) in at least 2/16 heart segments. EMB findings were graded according to the ISHLT criteria (2005 and 2013), and acute cellular rejection (ACR) grade ≥ 2 or antibody-mediated rejection (AMR) grade ≥ 1 were considered significant. The cutoff for abnormal dd-cfDNA was set at 0.2%. Solely clinical rejection included patients with absent or normal EMB (ACR grade 0-1 and AMR grade 0), but with symptoms or ECG/echocardiographic findings indicative of acute rejection. Results Our study revealed 22 acute rejections, with 15 confirmed through EMB and 7 diagnosed solely based on clinical indicators. Among the EMB-confirmed cases, 3/15 exhibited AMR grade 1, 10/15 demonstrated ACR grade 2 and 2/15 ACR grade 3. CMR identified rejection in 77% (17/22) of cases. Specifically, it successfully identified rejection in 67% (10/15) of EMB-confirmed cases and 100% (7/7) of solely clinically diagnosed cases. Examining the concordance between CMR findings and dd-cfDNA levels, 35% (6/17) of the CMR-identified rejection cases exhibited abnormal dd-cfDNA, while 30% (5/17) showed normal levels. Notably, in one case, despite normal CMR results, both EMB and dd-cfDNA indicated rejection. Conversely, in four instances where EMB indicated acute rejection, both CMR and dd-cfDNA levels were normal. These findings highlight a potential discrepancy in the diagnostic accuracy of EMB, suggesting its tendency to both over- and underdiagnose acute heart transplant rejection. The integration of CMR and dd-cfDNA in the diagnostic process may provide a more comprehensive and reliable assessment of rejection episodes, offering valuable insights for clinical decision-making in heart transplant recipients. Conclusions EMB presents challenges in both under- and overdiagnosing rejection in heart transplant surveillance. A strategy based on CMR, combined with dd-cfDNA analyses, shows promise as a new gold standard for rejection screening.Flowchart

Islet cell spheroids produced by a thermally sensitive scaffold: a new diabetes treatment

The primary issues in treating type 1 diabetes mellitus (T1DM) through the transplantation of healthy islets or islet β-cells are graft rejection and a lack of available donors. Currently, the majority of approaches use cell encapsulation technology and transplant replacement cells that can release insulin to address transplant rejection and donor shortages. However, existing encapsulation materials merely serve as carriers for islet cell growth. A new treatment approach for T1DM could be developed by creating a smart responsive material that encourages the formation of islet cell spheroids to replicate their 3D connections in vivo and controls the release of insulin aggregates. In this study, we used microfluidics to create thermally sensitive porous scaffolds made of poly(N-isopropyl acrylamide)/graphene oxide (PNIPAM/GO). The material was carefully shrunk under near-infrared light, enriched with mouse insulinoma pancreatic β cells (β-TC-6 cells), encapsulated, and cultivated to form 3D cell spheroids. The controlled contraction of the thermally responsive porous scaffold regulated insulin release from the spheroids, demonstrated using the glucose-stimulated insulin release assay (GSIS), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence assay. Eventually, implantation of the spheroids into C57BL/6 N diabetic mice enhanced the therapeutic effect, potentially offering a novel approach to the management of T1DM.Graphical