Acute Cardiac Rejection Research Articles

Cost analysis of cardiac MRI for cardiac transplant surveillance

National health expenditures in the United States have risen steadily since 1960. While lifesaving therapies exist for acquired and congenital heart diseases, for some children heart transplantation is their only chance for a period of durable survival. Like many advanced therapies, however, heart transplantation confers a significant cost to families and the health care system at large. Current heart transplant health surveillance relies on frequent cardiac catheterization with endomyocardial biopsy (cath-EMB) as periodic assessment of graft health and detection of possible life-threatening acute rejection. Cardiac magnetic resonance imaging (MRI) has emerged as a diagnostic tool which can characterize the myocardium, providing insights into graft health and potentially acute/chronic graft rejection. The PEACE study (R01-HL164995-02) aims to systematically evaluate the potential for using cardiac MRI parametric mapping as a pre-cath-EMB screening tool to alleviate both patient anxiety and discomfort, as well as the financial burden of cath-EMB. The PEACE trial aims to establish definitive evidence and criteria for determining when cath EMB is needed. For a technique to be practical in the real world, though, it must also be cost effective.Therefore, the goal of this current research is to determine a minimal set of measurement properties (positive predictive value (PPV), etc.) that cardiac MRI must attain to be cost-effective. These data will guide the decision-making for the PEACE trial results. Consistent with the recent emphasis on “Value MRI,” we sought to understand the potential Medicare savings, through economic cost analysis modeling, if cardiac MRI is used for cardiac transplant surveillance rather than cath-EMB surveillance. At even the most pessimistic positive test rate for MRI considered, these modeling results suggest substantial Medicare cost savings when using cardiac MRI parametric mapping as a screening tool for detecting acute cardiac rejection. Longitudinal cost savings are notable too.

Prediction of Acute Cardiac Rejection Based on Gene Expression Profiles.

Acute cardiac rejection remains a significant challenge in the post-transplant period, necessitating meticulous monitoring and timely intervention to prevent graft failure. Thus, the goal of the present study was to identify novel biomarkers involved in acute cardiac rejection, paving the way for personalized diagnostic, preventive, and treatment strategies. A total of 809 differentially expressed genes were identified in the GSE150059 dataset. We intersected genes selected by analysis of variance, recursive feature elimination, least absolute shrinkage and selection operator, and random forest classifier to identify the most relevant genes involved in acute cardiac rejection. Thus, HCP5, KLRD1, GZMB, PLA1A, GNLY, and KLRB1 were used to train eight machine learning models: random forest, logistic regression, decision trees, support vector machines, gradient boosting machines, K-nearest neighbors, XGBoost, and neural networks. Models were trained, tested, and validated on the GSE150059 dataset (MMDx-based diagnosis of rejection). Eight algorithms achieved great performance in predicting acute cardiac rejection. However, all machine learning models demonstrated poor performance in two external validation sets that had rejection diagnosis based on histology: merged GSE2596 and GSE4470 dataset and GSE9377 dataset, thus highlighting differences between these two methods. According to SHAP and LIME, KLRD1 and HCP5 were the most impactful genes.

(410) - Free-Breathing Cardiac Magnetic Resonance CMR Oedema Assessment in Acute Cardiac Rejection

(410) - Free-Breathing Cardiac Magnetic Resonance CMR Oedema Assessment in Acute Cardiac Rejection

Toll-like receptor 2 deficiency promotes the generation of alloreactive γδT17 cells after cardiac transplantation in mice

Homograft rejection is the main cause of heart transplantation failure. The role of TLR2, a major member of the toll-like receptor (TLR) family, in transplantation rejection is has yet to be elucidated. In this study, we used a mouse model of acute cardiac transplantation rejection to investigate whether the TLR2 signalling pathway can regulate cardiac transplantation rejection by regulating alloreactive IL-17+γδT (γδT17) cells. We found that the expression of TLR2 on the surface of dendritic cells (DCs) and macrophages increased during acute transplantation rejection. In addition, our investigation revealed that γδT17 cells exert a significant influence on acute cardiac transplantation rejection. TLR2 gene knockout resulted in an increase in alloreactive γδT17 cells in the spleen and heart grafts of recipient mice compared with wild-type recipient mice and an increase in the mRNA expression of IL-17, IL-1β, CCR6, and CCL20 in the heart grafts. In an in vitro experiment, a mixed lymphocyte reaction was conducted to assess the impact of TLR2 deficiency on the generation of γδT17 cells, which further substantiated a significant increase compared to that in wild-type controls. Furthermore, the mixed lymphocyte reaction showed that TLR2 regulated the production of γδT17 cells by regulating the ability of DCs to secrete IL-1β. These results suggest that TLR2 signalling is important for regulating the generation of γδT17 cells after cardiac allograft transplantation.

Doppler echocardiography for surveillance of acute cardiac allograft rejection: a 28-year single-center experience.

Endomyocardial biopsies (EMB) are recommended for the detection of acute cardiac rejection (ACR) despite limited sensitivity. We report the long-term post-transplant results of Doppler echocardiography as a noninvasive alternative of routine EMB. Two cohorts of heart transplantation (HT) recipients were chronologically defined as follows: the Dual Monitoring Cohort (DMC) from January 1990 to December 1997 included patients who underwent routine EMB and Doppler echocardiography within 24 hours for ACR surveillance; and the "Echo-First Cohort" (EFC), including patients transplanted from January 1998 to December 2018 with Doppler echocardiography as first-line approach for ACR surveillance. Echocardiographic measurements of interest were collected: early diastolic (E) wave peak velocity; pressure half time (PHT) and isovolumetric relaxation time (IVRT). Post-transplant outcomes were reviewed and the Kaplan-Meier approach was used for survival estimates. Inter-operator variability for ultrasound measurements was investigated. Data were collected from medical records from January 2019 to December 2020. A total of 228 patients were included, 99 patients in the DMC and 129 in the EFC. Overall, 5-, 10- and 15-year survival rates were 65.4%, 55.5% and 44.1% respectively, without any significant difference between the two cohorts (log rank test, P=0.71). Echocardiography variables and EMB findings were associated with a mean area under the receiver operating characteristic curve (AUC-ROC) of 0.73 [95% confidence interval (CI): 0.54-0.91], 0.74 (95% CI: 0.54-0.94) and 0.75 (95% CI: 0.57-0.94) respectively for E wave, PHT and IVRT. IVRT and PHT were significantly decreased, and E wave significantly increased, in case of histologically proven ACR. Inter-operator variability was not significant for E wave and IVRT measurements (P=0.13 and 0.30 respectively). Doppler echocardiography as a first-line method for surveillance of ACR did not impair long-term results after HT. These findings suggest that this non-invasive approach might be a reasonable alternative to systematic EMB, limiting risk and improving the quality of life.

Kiosk 7R-TC-07 - T2 Quantification in Acute Cardiac Rejection: A Comparison of Breath-hold and FBee-breathing Sequences

Kiosk 7R-TC-07 - T2 Quantification in Acute Cardiac Rejection: A Comparison of Breath-hold and FBee-breathing Sequences

ВОПРОСЫ ДОГОСПИТАЛЬНОЙ ДИАГНОСТИКИ ОСТРОЙ РЕАКЦИИ ОТТОРЖЕНИЯ У ПАЦИЕНТА, ПЕРЕНЕСШЕГО ОРТОТОПИЧЕСКУЮ ТРАНСПЛАНТАЦИЮ СЕРДЦА

An acute cardiac transplant rejection is a reaction of the recipient’s immune system, which includes the cellular and/or humoral pathway of the immune response. This reaction is directed against the tissues of the “alien” donor organ. The alertness of clinicians regarding the possible development of an acute rejection reaction during the first year after heart transplantation is due to the extremely high risk of developing life-threatening conditions mediated by graft dysfunction. These include various cardiac arrhythmias and a progressive decrease in myocardial contractility. In case of untimely diagnosis of this serious complication, the risk of mortality of the patient who underwent orthotopic heart transplantation is extremely high. What changes in clinical, laboratory and instrumental examination parameters at the outpatient stage can help a practicing cardiologist to suspect the presence of an acute rejection reaction of a heart transplant in a patient who has undergone orthotopic heart transplantation? At present, there is no unambiguous answer to this question, and the topic of early detection and prediction of the development of an acute heart transplant rejection reaction is extremely relevant for modern scientific research and is of great practical interest in the field of transplantology and cardiology, in particular.

Total Lymphoid Irradiation in the Treatment of Heart Transplant Rejection: Single Institution Long-Term Results

Acute cardiac allograft rejection is a major cause of morbidity and mortality post-transplant. Total lymphoid irradiation (TLI) has been shown to cause long-lasting alterations in lymphocyte sub-sets, and thereby induces a state of partial response that is useful to prevent organ transplant rejection. In our previous report, treatment with TLI resulted in decreased episodes of acute rejection and steroid dosage requirements for up to 9.1 years post cardiac transplantation. In this study, we report an update on the short- and long-term effects of TLI in the treatment of cardiac transplant rejection. We performed a retrospective analysis of patients with intractable cardiac allograft transplantation evaluated in the department of radiation oncology at our institution over 23 years (1998-2021). Cardiac allograft rejection was defined as multiple or persistent episodes of rejection despite aggressive immunosuppressive therapy. The prescribed dose was 8 Gy in 10 fractions to be delivered over 5 weeks. All episodes of pathologic acute cardiac rejection, duration of immunosuppression, and episodes of acute infection requiring treatment before and after TLI were documented. Overall survival (OS) was analyzed using Kaplan-Meier method. The median time to first cardiac allograft rejection and the median time to first acute rejection was monitored. Of the 29 patients included, 21 (72.4%) had ISHLT grade 1R, 5 (17.2%), grade 2R, and 2(6.9%) grade 3R rejection. Rejection grade was unknown for 1 patient. The mean number of acute rejections after transplant was 14.4 episodes per patient (range 1-44) with median time to first rejection of 0.63 months. The median radiation dose was 8 Gy (range 7.2-8 Gy) delivered over a mean of 31 days. Treatment was stopped early in 2 (6.5%) patients (after 7.2 Gy and 7.9 Gy) for severe bone marrow suppression and drop in CD4 counts, respectively. The number of rejections dropped from 14.2 to 3.97 per patient over a median time of 29.0 months vs 28.1 months pre and post TLI (p = 0.01). The frequency of ISHLT acute grade 3R rejections decreased from 0.58 to 0.06 episodes per patient pre and post TLI (p = 0.02). Immunosuppressant requirements decreased from 2.83 before TLI to 2.69 after TLI (p = 0.71). Infection rates per patient were 0.71 pre TLI and remained at 0.63 post TLI. Treatment was well tolerated with 4 (13.8%) grade 2 or higher radiation toxicity. Median follow up was 76.3 months. Median and 3-year OS were 53.4 months and 60.9%, respectively. TLI is a safe and effective treatment for control of intractable cardiac rejection. The episodes of acute rejection and immunosuppressant requirements are decreased, but with long-term follow up, these patients continue to experience rejection. However, TLI lowers the frequency of ISHLT moderate to severe rejection episodes for up to 6.4 years. There was no increased risk of severe infections and there were only minimal short- and long-term grade 2 or higher radiation toxicities.

Small-molecule BCL6 inhibitor protects chronic cardiac transplant rejection and inhibits T follicular helper cell expansion and humoral response.

Background: B cell lymphoma 6 (BCL6) is an important transcription factor of T follicular helper (Tfh) cells, which regulate the humoral response by supporting the maturation of germinal center B cells and plasma cells. The aim of this study is to investigate the expansion of T follicular helper cells and the effect of the BCL6 inhibitor FX1 in acute and chronic cardiac transplant rejection models. Methods: A mouse model of acute and chronic cardiac transplant rejection was established. Splenocytes were collected at different time points after transplantation for CXCR5+PD-1+ and CXCR5+BCL6+ Tfh cells detection by flow cytometry (FCM). Next, we treated the cardiac transplant with BCL6 inhibitor FX1 and the survival of grafts was recorded. The hematoxylin and eosin, Elastica van Gieson, and Masson staining of cardiac grafts was performed for the pathological analysis. Furthermore, the proportion and number of CD4+ T cells, effector CD4+ T cells (CD44+CD62L-), proliferating CD4+ T cells (Ki67+), and Tfh cells in the spleen were detected by FCM. The cells related to humoral response (plasma cells, germinal center B cells, IgG1+ B cells) and donor-specific antibody were also detected. Results: We found that the Tfh cells were significantly increased in the recipient mice on day 14 post transplantation. During the acute cardiac transplant rejection, even the BCL6 inhibitor FX1 did not prolong the survival or attenuate the immune response of cardiac graft, the expansion of Tfh cell expansion inhibit. During the chronic cardiac transplant rejection, FX1 prolonged survival of cardiac graft, and prevented occlusion and fibrosis of vascular in cardiac grafts. FX1 also decreased the proportion and number of splenic CD4+ T cells, effector CD4+ T cells, proliferating CD4+ T cells, and Tfh cells in mice with chronic rejection. Moreover, FX1 also inhibited the proportion and number of splenic plasma cells, germinal center B cells, IgG1+ B cells, and the donor-specific antibody in recipient mice. Conclusion: We found BCL6 inhibitor FX1 protects chronic cardiac transplant rejection and inhibits the expansion of Tfh cells and the humoral response, which suggest that BCL6 is a potential therapeutic target of the treatment for chronic cardiac transplant rejection.

The dynamic cellular landscape of grafts with acute rejection after heart transplantation.

Acute cellular rejection (ACR) is a major barrier to the long-term survival of cardiac allografts. Although immune cells are well known to play critical roles in ACR, the dynamic cellular landscape of allografts with ACR remains obscure. Single-cell RNA sequencing (scRNA-seq) was carried out for mouse cardiac allografts with ACR. Bioinformatic analysis was performed, and subsequent transplant experiments were conducted to validate the findings. Despite an overall large depletion of cardiac fibroblasts (CFBs), highly expanded cytotoxic T lymphocytes and a CXCL10+Gbp2+ subcluster of CFBs were enriched within grafts at the late stage. CXCL10+Gbp2+ CFBs featured strong interferon responsiveness and high expression of chemokines and major histocompatibility complex molecules, implying their involvement in the recruitment and activation of immune cells. Cell‒cell communication analysis revealed that CXCL9/CXCL10-CXCR3 might contribute to regulating CXCL10+Gbp2+ CFB-induced chemotaxis and immune cell recruitment. In vivo transplant studies revealed the therapeutic potential of CXCR3 antagonism in transplant rejection. The findings of our study unveiled a novel CFB subcluster that might mediate acute cardiac rejection. Targeting CXCR3 could prolong allograft survival.

Beyond the AJR: Cardiac MRI Accurately Detects Acute Cardiac Transplant Rejection.

Beyond the AJR: Cardiac MRI Accurately Detects Acute Cardiac Transplant RejectionChristopher J. François, MD1Audio Available | Share

ZBTB20 regulates cardiac allograft rejection through NFкB-mediated inflammation in mouse heart transplantation

Allograft rejection is a major obstacle for the long-term survival of heart transplantation (Htx) patients. The cardiac allograft rejection requires the activation of macrophages and effector T cells. In this study, we explored the role of zinc-finger and BTB domain containing protein 20 (ZBTB20) in the regulation of heart allograft rejection. Flow cytometry analysis of the spleen cells from mice undergoing an acute cardiac rejection revealed that the ZBTB20 protein expression was upregulated in both T and B cells(n = 4，P < 0.01). In addition, ZBTB20 gene knockdown significantly prolonged the survival of heart allografts in mice(n = 4，P < 0.01). Lack of ZBTB20 increased the expression of Foxp3 and limited the response of T helper 1 (Th1) cells(n = 4，P < 0.01). The ZBTB20-related regulation occurred through the activation of the NFкB pathway. In conclusion, our data suggest that ZBTB20 is involved in the regulation of T cells involved in acute heart allograft rejection. Hence, downregulation of ZBTB20 expression may inhibit T cells to prolong heart transplant survival.

The Combination of Rhodosin and MMF Prolongs Cardiac Allograft Survival by Inhibiting DC Maturation by Promoting Mitochondrial Fusion.

Despite being the gold-standard treatment for end-stage heart disease, heart transplantation is associated with acute cardiac rejection within 1 year of transplantation. The continuous application of immunosuppressants may cause side effects such as hepatic and renal toxicity, infection, and malignancy. Developing new pharmaceutical strategies to alleviate acute rejection after heart transplantation effectively and safely is of critical importance. In this study, we performed a murine model of MHC-full mismatch cardiac transplantation and showed that the combination of Rhodosin (Rho) and mycophenolate mofetil (MMF) could prevent acute rejection and oxidative stress injury and prolong the survival time of murine heart transplants. The use of Rho plus MMF in allografts improved the balance of Tregs/Teff cells, which had a protective effect on allotransplantation. We also isolated bone marrow-derived dendritic cells (BMDCs) and determined that Rho inhibited DC maturation by promoting mitochondrial fusion mainly through the mitochondrial fusion-related protein MFN1. Herein, we demonstrated that Rho, an active ingredient isolated from the plant Rhodiola rosea with antioxidant and anti-inflammatory activities, could efficiently alleviate acute rejection and significantly prolong murine heart allograft survival when used with a low dose of MMF. More importantly, we found that Rho restrained DC maturation by promoting mitochondrial fusion and decreasing reactive oxygen species (ROS) levels, which then alleviated acute rejection in murine cardiac transplantation. Interestingly, as a novel immunosuppressant, Rho has almost no side effects compared with other traditional immunosuppressants. Taken together, these results suggest that Rho has good clinical auxiliary applications as an effective immunosuppressant and antioxidant, and this study provides an efficient strategy to overcome the side effects of immunosuppressive agents that are currently used in organ transplantation.

Exosomes: Potential executors of IL‐35 gene‐modified adipose‐derived mesenchymal stem cells in inhibiting acute rejection after heart transplantation

Heart transplantation has become the only 'cure' for end-stage heart diseases, but acute allograft rejection is the major obstacle to the survival of patients. Our previous studies showed that IL-35 gene-modified adipose-derived mesenchymal stem cells (IL-35-ASCs) can effectively inhibit graft rejection and prolong the survival of transplanted hearts in mice. This study further explored the mechanism of IL-35-ASCs, especially focusing on the important role of IL-35-ASC-derived exosomes (IL-35-ASCexos) in inhibiting acute rejection. IL-35-ASCs were constructed in vitro and pretreated with IL-35 neutralizing antibody and GW4869 (an inhibitor of neutral sphingomyelinase that impairs exosome biogenesis/release). Then, pretreated IL-35-ASCs and CD4+ T cells were cocultured in Transwell plates, and changes in regulatory T cells (Tregs) and cytokines were detected. Then, IL-35-ASCexos were extracted, identified and analysed, and their immunoregulatory effects on CD4+ T cells were studied through coculture experiments. Finally, IL-35-ASCexos were applied to a mouse heart transplantation model to investigate the therapeutic effects on acute rejection of the allograft. The coculture experiment showed that the IL-35-neutralizing antibody could not completely block the immunosuppressive function of IL-35-ASCs, while GW4869 could effectively reduce their immunoregulatory characteristics. Similar to IL-35-ASCs, IL-35-ASCexos also have powerful immunosuppressive properties, effectively upregulating the Treg ratio in vivo and in vitro and prolonging graft survival. As the main effectors of IL-35-ASCs, these findings highlight the therapeutic potential of IL-35-ASCexos in inhibiting acute cardiac rejection of the allograft. Although the specific mechanism remains unclear and needs to be further explored, IL-35-ASCexos therapy is expected to become a new method to inhibit acute graft rejection.

Diagnostic Accuracy of Cardiovascular Magnetic Resonance for Cardiac Transplant Rejection: A Meta-Analysis

ObjectivesThe aim of this meta-analysis was to assess the diagnostic performance of various CMR imaging parameters for evaluating acute cardiac transplant rejection. BackgroundEndomyocardial biopsy is the current gold standard for detection of acute cardiac transplant rejection. Cardiac magnetic resonance (CMR) is uniquely capable of myocardial tissue characterization and may be useful as a noninvasive alternative for the diagnosis of graft rejection. MethodsPubMed and Web of Science were searched for relevant publications reporting on the use of CMR myocardial tissue characterization for detection of acute cardiac transplant rejection with endomyocardial biopsy as the reference standard. Pooled sensitivity, specificity, and hierarchical modeling–based summary receiver-operating characteristic curves were calculated. ResultsOf 478 papers, 10 studies comprising 564 patients were included. The sensitivity and specificity for the detection of acute cardiac transplant rejection were 84.6 (95% CI: 65.6-94.0) and 70.1 (95% CI: 54.2-82.2) for T1, 86.5 (95% CI: 72.1-94.1) and 85.9 (95% CI: 65.2-94.6) for T2, 91.3 (95% CI: 63.9-98.4) and 67.6 (95% CI: 56.1-77.4) for extracellular volume fraction (ECV), and 50.1 (95% CI: 31.2-68.9) and 60.2 (95% CI: 36.7-79.7) for late gadolinium enhancement (LGE). The areas under the hierarchical modeling–based summary receiver-operating characteristic curve were 0.84 (95% CI: 0.81-0.87) for T1, 0.92 (95% CI: 0.89-94) for T2, 0.78 (95% CI: 0.74-0.81) for ECV, and 0.56 (95% CI: 0.51-0.60) for LGE. T2 values demonstrated the highest diagnostic accuracy, followed by native T1, ECV, and LGE (all P values <0.001 for T1, ECV, and LGE vs T2). ConclusionsT2 mapping demonstrated higher diagnostic accuracy than other CMR techniques. Native T1 and ECV provide high diagnostic use but lower diagnostic accuracy compared with T2, which was related primarily to lower specificity. LGE showed poor diagnostic performance for detection of rejection.

Prolyl endopeptidase contributes to early neutrophilic inflammation in acute myocardial transplant rejection.

Altered inflammation and tissue remodeling are cardinal features of cardiovascular disease and cardiac transplant rejection. Neutrophils have increasingly been understood to play a critical role in acute rejection and early allograft failure; however, discrete mechanisms that drive this damage remain poorly understood. Herein, we demonstrate that early acute cardiac rejection increases allograft prolyl endopeptidase (PE) in association with de novo production of the neutrophil proinflammatory matrikine proline-glycine-proline (PGP). In a heterotopic murine heart transplant model, PGP production and PE activity were associated with early neutrophil allograft invasion and allograft failure. Pharmacologic inhibition of PE with Z-Pro-prolinal reduced PGP, attenuated early neutrophil graft invasion, and reduced proinflammatory cytokine expression. Importantly, these changes helped preserve allograft rejection-free survival and function. Notably, within 2 independent patient cohorts, both PGP and PE activity were increased among patients with biopsy-proven rejection. The observed induction of PE and matrikine generation provide a link between neutrophilic inflammation and cardiovascular injury, represent a potential target to reduce allogenic immune responses, and uncover a mechanism of cardiovascular disease that has been previously unrecognized to our knowledge.

Establishment of Methods Indentifying Genes Associated with Acute Cardiac Cellular Rejection Using a Small Thin Slice Specimen

Purpose Endomyocardial biopsy (EMB) is a gold standard to detect acute cellar cardiac rejection (ACR), but due to its invasiveness, a new non-invasive approach is warranted. Our final goal is to identify new biomarkers corresponding to ACR severity. Using RNA-seq analysis, we found specific gene expression profiles in EMB specimens corresponding to the grades of ISHLT criteria. We also established a transcriptome analysis method utilizing an FFPE (formalin fixed paraffin embedded) EMB section remained after pathological examination. Methods 1. Gene expression profiling in fresh frozen EMB section: 7 cardiac recipients who had pathological ACR were enrolled. They were divided into two groups: patients with before and at rejection ISHLT grade 1A (G-going; N=3) and with at and after treating rejection grade 1A (G-resolving; N=4). Transcriptome analysis was performed using a fresh frozen section (0.5 - 3 mm wide, 7 µm thickness). 2. Establishment of a 3’mRNA-seq method utilizing thin FFPE EMB section: 28 myocardial specimens (grade 0 in 7, 1A in 12, 2 in 2, 3A in 4 and quilty in 3) were analyzed. 3’mRNA-seq libraries were prepared using total RNA isolated from an FFPE section (1-2 mm wide, 5 µm) remained after pathological examination. 3. GSEA (Gene Set Enrichment Analysis) and DGE analysis: After RNA-sequencing, gene expression profiling was analyzed by GSEA and clustered by k-means. Results In G-going, we identified up-regulation of the genes mainly related to ACR, interferon gamma, inflammation, and ILG-JAK-STAT3 signaling, while in G-resolving, we identified down-regulation of these genes. Inflammatory responses were also observed in 3’mRNA-seq analysis using FFPE section. We also separated 270 up-regulating genes in grade3A and 229 ACR related genes associated with ISHLT criteria. In our analysis, most of these identified genes were not listed in AlloMap ®. Conclusion Although these analyses were preliminary because of the 1st analysis stage, these technique for analyzing gene expressions using a tiny myocardial sample may have a role to find new biomarkers associated with ACR.

PJ34, a PARP1 inhibitor, attenuates acute allograft rejection after murine heart transplantation via regulating the CD4+ T lymphocyte response.

Acute allografts rejection is the most important factor causing allograft disability for many patients undergoing organ transplantation. PJ34, which is a specific inhibitor of poly(ADP-ribose) polymerase 1, is involved in immune regulation, may be effective in preventing acute cardiac rejection. We performed the models of abdominal heterotopic heart transplantation. PJ34 was injected intraperitoneally daily (20mg/kg/day) starting the day after surgery. The severity of rejection was determined by histology. The mRNA expression levels of cytokines and transcription factors in the grafts were measured by quantitative polymerase chain reaction (qPCR). The proportion and number of T-cell subpopulations in the spleens were analyzed by flow cytometry. In vitro, the effect of PJ34 on allogeneic responses was investigated. We found treatment with PJ34 prolonged allograft survival compared with normal saline treatment. Compared with the control group, PJ34 treatment reduced the proportion of CD4+ IFN-γ+ and CD4+ IL-17A+ cells and increased the percent of CD4+ IL-4+ and CD4+ Foxp3+ cells in the spleens. In vitro, PJ34 treatment significantly inhibited the mRNA levels of IFN-γ and IL-17A and promoted the mRNA levels of TGF-β and FOXP-3 in activated CD4+ T cells. Modulating the CD4+ T lymphocyte response with PJ34 could attenuate acute allografts rejection after murine heart transplantation. These findings indicate that PARP1 may be a promising therapeutic target to attenuate acute cardiac allograft rejection.

Noninvasive Radionuclide Molecular Imaging of the CD4-Positive T Lymphocytes in Acute Cardiac Rejection.

Heart transplantation (HT) is an effective treatment for end-stage heart disease. However, acute rejection (AR) is still the main cause of death within one year after HT. AR is an acute immune response mediated by T lymphocytes, mainly CD4+ T lymphocytes. This study innovatively develops a radiolabeled probe 99mTc-HYNIC-mAbCD4 for noninvasive visualization of CD4+ T lymphocyte infiltration and detection of AR. The 99mTc-HYNIC-mAbCD4 and its isotype control 99mTc-HYNIC-IgG were successfully prepared and characterized. The specificity and affinity of the probe in vitro were assessed by cell-binding experiments. Binding of 99mTc-HYNIC-mAbCD4 to CD4+ T lymphocytes was higher than that of the macrophages and IgG probe groups, and mAbCD4 was effective in the blockade of the binding reaction. The biodistribution data confirmed the SPECT/CT images, with significantly higher levels of 99mTc-HYNIC-mAbCD4 observed in allografts compared to allograft treatment (10 mg/kg/d Cyclosporin A subcutaneously for 5 consecutive days after surgery), isografts, or in rats which received allografts injected with 99mTc-HYNIC-IgG. Histological examination confirmed more CD4+ T lymphocyte infiltration in the allograft hearts than other groups. In summary, 99mTc-HYNIC-mAbCD4 achieved high affinity and specificity of binding to CD4+ T lymphocytes and accumulation in the transplanted heart. Radionuclide molecular imaging with 99mTc-HYNIC-mAbCD4 may be a potential diagnostic method for acute cardiac rejection.

Heart transplantation in diabetic recipients

Introduction . Heart transplantation (HT) in patients with preexisting type 2 diabetes (T2D) is associated with high risk of infectious and non-infectious complications (renal dysfunction, multifocal atherosclerosis, transplant coronary artery disease, etc.) that can negatively affect recipient survival in the early and late periods after HT. Objective: to assess the effect of pre-transplant T2D on early and long-term outcomes of HT based on a singlecenter retrospective study. Materials and methods . The study enrolled 891 recipients who underwent HT within the period 2011 to 2018, and were divided into two groups: main group (T2D) – recipients with pretransplant T2D (n = 80, 9.0%) and the control group (T2D-free) – recipients without T2D (n = 811, 91.0%). Recipients from both groups did not differ in terms of HT urgency (UNOS status) and the need for pre-transplant mechanical circulatory support (MCS). Results . At the time of the HT, recipients from the T2D group were older than the T2D-free recipients (54 [46; 59] years vs 48 [35; 56] years, p &lt; 0.001), they had a higher weight (p &lt; 0.001) and body mass index (p &lt; 0.001), coronary heart disease was more often their main disease (65.0% vs 36.5%, p &lt; 0.001), they had higher transpulmonary gradient (10.0 [7.0; 12.0] mm Hg vs 9.0 [6.0; 12.0] mm Hg, p = 0.024) and pulmonary vascular resistance (2.9 [2.2; 4.0] Wood units vs 2.5 [1.8; 3.4] Wood units, p = 0.038). In the pre-transplant period, the T2D group had pronounced manifestations of renal dysfunction and increased comorbidity. Recipients in both groups did not differ in terms of cardiac donor parameters, graft ischemia time, cardiopulmonary bypass time, and incidence of severe early heart graft dysfunction requiring MCS (12.5% vs 10.7%, p = 0.74). In the early post-transplant period, the T2D group had high requirements (100% vs 28.0%, p &lt; 0.001) and higher doses of insulin therapy. More pronounced manifestations of renal dysfunction and a greater need for renal replacement therapy (51.4% vs 27.9%, p = 0.003) did not affect artificial ventilation and ICU duration (6 [5; 10] days vs 6 [5; 10] days, p = 0.098), as well as hospital mortality ( 8.8% vs 8.5%, p = 0.895). The presence of pre-transplant T2D had no negative effect on the incidence of acute cardiac graft rejection, progression of transmissible coronary atherosclerosis, incidence and severity of cardiac graft vasculopathy, structure and severity of distant infectious and non-infectious complications, and post-transplant survival. Conclusion . With correct selection of recipients and choice of optimal tactics for their post-transplant management, the presence of pre-transplant T2D has no negative effect on early and long-term outcomes of HT.