The association between body mass index, exercise capacity, and health-related quality of life in heart transplant recipients.

Introduction: Pre-transplant obesity and weight gain after heart transplantation are both associated with increased risk of poor clinical outcomes. We aimed to assess the association between overweight or obesity, exercise capacity, and health-related quality of life in heart transplant recipients. Methods: This study is based on baseline data from the IronIC trial, in which we randomized 102 heart transplant recipients with iron deficiency to ferric derisomaltose or placebo. We performed cardio pulmonary exercise testing in all participants. To assess quality of life, we used the SF-36v2 questionnaire, using two sum scores: the physical component summary and the mental component summary. A minimal clinically important difference was defined as ≥2 and ≥3 for the physical and the mental component summary, respectively. Results: 24/102 heart transplant recipients (24%) had a body mass index (BMI) ≥30 kg/m2. Peak oxygen consumption was 17.3 ± 4.6 ml/kg/min in the obese group vs. 24.7 ± 6.4 ml/kg/min in the group with a BMI <30 for a between-group difference of 7.4 (95% confidence interval 4.7-10.2) ml/kg/min: p < 0.001. The physical component summary score was on average 5.2 points lower in the patients with a body mass index ≥30 than in the lower weight group (p = 0.04). Conclusion: Almost a quarter of our heart transplant recipients in long-term follow-up had a BMI ≥30 kg/m2. These patients had substantially lower exercise capacity and lower quality of life in the physical domain.

Meta-analysis and systematic review of gout prevalence in the heart/lung transplantation population.

Introduction: Gout may complicate solid organ transplantation with potentially serious consequences. An accurate prevalence of gout in this population is unknown. Objectives: This study aimed to estimate the prevalence of gout in the heart and/or lung transplantation population through a systematic review and meta-analysis. Methods: MEDLINE, Embase, PsycINFO, CENTRAL and Cochrane Library (inception to February 2022) were searched for studies that reported the prevalence and/or incidence of gout in heart and/or lung transplant recipients. Two authors extracted outcomes data. Data were pooled using a random effects model. Overall quality of evidence was assessed using GRADE. Primary outcomes were the prevalence of pre- or post-transplant gout expressed as a prevalence rate (95% CI). Secondary outcomes included risk factors for gout, adverse events, and therapeutic complications of gout treatment. Results: Ten studies were included. Gout prevalence (PR) was 8% pre-transplant (PR = 0.08; 95% CI: 0.05-0.12; 4 studies n = 651) and 6% post-transplant (PR = 0.06; 95% CI: 0.06-0.06; 10 studies n = 45,298). Post-transplant gout prevalence in heart transplant recipients was almost three times higher than lung transplant recipients (PR = 0.16; 95% CI: 0.13-0.20 vs. PR = 0.06; 95% CI: 0.05-0.06 respectively). Patients with a pre-transplant history of gout had a higher risk of developing post-transplant gout than patients without (RR = 3.61; 95% CI: 2.19-5.95). Factors associated with gout and outcomes for heart and/or lung transplant recipients with gout were comprehensively reviewed from the included studies. Conclusion: Gout is highly prevalent in heart and/or lung transplant patients. Pre-transplant gout is predictive of developing symptomatic post-transplant gout. This has significant implications for management of heart/lung transplant patients. Systematic Review Registration: https://www.crd.york.ac.uk/, PROSPERO (CRD42020190632).

Critical care therapies pre- and post-heart transplant and their impact: Analysis from the Pediatric Cardiac Critical Care Consortium.

BACKGROUND: Few studies highlighting the critical care management of patients after heart HTx (HTx) have been published to date. This analysis provides a contemporary representation of pre- and post-HTx critical care in various patient cohorts and outlines the impact of intensive care unit (ICU) therapies on outcomes. METHODS: Data from PC4 Collaborative Registry were analyzed for pediatric patients undergoing HTx between August 2014 and April 2022. RESULTS: A total of 1877 HTx in 1857 patients were reported from 42 centers; 56.5% had congenital heart disease (CHD). Patients with CHD were younger, smaller, more likely male, White race, and publicly insured. CHD patients had higher need for catheterization, increased likelihood of inotropic support and mechanical ventilation and lower VAD rates. Their operative courses were significant for longer bypass and cross-clamp times. Postoperatively, CHD patients required more CPR , utilized more ICU therapies and had higher hospital mortality (7.8% vs. 1.8% for non-CHD patients, p<0.0001). Longer cardiopulmonary bypass, longer deep hypothermic circulatory arrest times and delayed sternal closure were independent risk factors for hospital mortality. Lastly, center transplant volume but not surgical volume was associated with transplant outcomes. CONCLUSIONS: A diagnosis of CHD before HTx is associated with a greater use of ICU-specific therapies compared non-CHD cohort. Operative factors, particularly in patients with CHD, are independently associated with higher hospital mortality as was low transplant volume at the center. The study provides basis for further investigating ICU and operative factors that can be modified to improve transplant outcomes.

Mechanism Exploration on the Immunoregulation of Allogeneic Heart Transplantation Rejection in Rats With Exosome miRNA and Proteins From Overexpressed IDO1 BMSCs.

Immunoregulation and indoleamine 2,3-dioxygenase 1 (IDO1) play pivotal roles in the rejection of allogeneic organ transplantation. This study aims to elucidate the immune-related functional mechanisms of exosomes (Exos) derived from bone marrow-derived mesenchymal stem cells (BMSCs) overexpressing IDO1 in the context of allogeneic heart transplantation (HTx) rejection. A rat model of allogeneic HTx was established. Exos were extracted after transfection with oe-IDO1 and oe-NC from rat BMSCs. Exos were administered via the caudal vein for treatment. The survival of rats was analyzed, and reverse transcription qualitative PCR (RT-qPCR) and immunohistochemistry (IHC) were employed to detect the expression of related genes. Histopathological examination was conducted using hematoxylin and eosin (HE) staining, and flow cytometry was utilized to analyze T-cell apoptosis. Proteomics and RNA-seq analyses were performed on Exos. The data were subjected to functional enrichment analysis using the R language. A protein interaction network was constructed using the STRING database, and miRWalk, TargetScan, and miRDB databases predicted the target genes, differentially expressed miRNAs, and transcription factors (TFs). Exos from BMSCs overexpressing IDO1 prolonged the survival time of rats undergoing allogeneic HTx. These Exos reduced inflammatory cell infiltration, mitigated myocardial damage, induced CD4 T-cell apoptosis, and alleviated transplantation rejection. The correlation between Exos from BMSCs overexpressing IDO1 and immune regulation was profound. Notably, 13 immune-related differential proteins (Anxa1, Anxa2, C3, Ctsb, Hp, Il1rap, Ntn1, Ptx3, Thbs1, Hspa1b, Vegfc, Dcn, and Ptpn11) and 10 significantly different miRNAs were identified. Finally, six key immune proteins related to IDO1 were identified through common enrichment pathways, including Thbs1, Dcn, Ptpn11, Hspa1b, Il1rap, and Vegfc. Thirteen TFs of IDO1-related key miRNAs were obtained, and a TF-miRNA-mRNA-proteins regulatory network was constructed. Exosome miRNA derived from BMSCs overexpressing IDO1 may influence T-cell activation and regulate HTx rejection by interacting with mRNA.

Gene therapy during ex situ heart perfusion: a new frontier in cardiac regenerative medicine?

Ex situ organ preservation by machine perfusion can improve preservation of organs for transplantation. Furthermore, machine perfusion opens up the possibilities for selective immunomodulation, creation of tolerance to ischemia-reperfusion injury and/or correction of a pathogenic genetic defect. The application of gene modifying therapies to treat heart diseases caused by pathogenic mutations during ex situ heart perfusion seems promising, especially given the limitations related to delivery of vectors that were encountered during clinical trials using in vivo cardiac gene therapy. By isolating the heart in a metabolically and immunologically favorable environment and preventing off-target effects and dilution, it is possible to directly control factors that enhance the success rate of cardiac gene therapy. A literature search of PubMed and Embase databases was performed to identify all relevant studies regarding gene therapy during ex situ heart perfusion, aiming to highlight important lessons learned and discuss future clinical prospects of this promising approach.

Transcatheter aortic valve replacement among heart transplant recipients with donor aortic valve diseases: a systematic review of the literature.

BACKGROUND: Despite high surgical risk among heart transplant (HTx) recipients, who develop aortic valve diseases (AVD), transcutaneous aortic valve replacement (TAVR) has been scarcely reported as a viable option in this patient population. METHODS: A systematic review was conducted to identify studies reporting the outcomes of HTx recipients who developed AVD of the donor heart and underwent TAVR. Studies were eligible if they provided individual-level data for HTx recipients, who underwent TAVR on the donor heart. Review articles, editorials or commentaries, studies lacking original data, or those reporting surgical valve replacement for AVD in HTx recipients were excluded. RESULTS: A total of 15 case reports, encompassing 15 patients, describing characteristics and outcomes of HTx recipients undergoing TAVR were included. These included 13 males and 2 females with an average age of 63.6±15 years. The indications for HTx were non-ischemic dilated cardiomyopathy, ischemic cardiomyopathy and ischemic dilated cardiomyopathy in 42.9%, 35.7%, and 21.4% of the patients, respectively. The main indication for aortic valve replacement (AVR) among HTx recipients was aortic stenosis (73.3%). The transcutaneous approach was preferred over surgical AVR due to high surgical risk in > 50% of the patients. Both pre-TAVR transvalvular pressure gradient and the peak aortic pressure gradient decreased after the TAVR. Paravalvular leak was minimal/none to mild in all the patients post-TAVR. Most patients had an uneventful post-TAVR recovery with no recurrence of the symptoms or echocardiographic finings at a median follow-up of 6 months. CONCLUSIONS: TAVR seems to be a viable option for HTx recipients who develop donor aortic valve diseases. However, there is a paucity of knowledge on the long-term survivability of the replaced aortic valves and the clinical and echocardiographic outcomes of HTx recipients undergoing TAVR.

Clinical course of congestive hepatopathy pre/post heart transplantation.

BACKGROUND AND AIMS: Heart failure (HF) might lead to increased hepatic venous pressure, thereby impairing hepatic blood outflow and subsequently inducing congestive hepatopathy. We aimed to evaluate prevalence of congestive hepatopathy in patients undergoing heart transplantation (HTX) as well as their post-transplant course. METHODS: Patients undergoing HTX from 2015-2020 at the Vienna General Hospital were included (n = 205). Congestive hepatopathy was defined by hepatic congestion on abdominal imaging and hepatic injury. Laboratory parameters, ascites severity, and clinical events were assessed and post-HTX outcomes evaluated. RESULTS: At listing, 104 (54%) patients showed hepatic congestion, 97 (47%) hepatic injury, and 50 (26%) had ascites. Congestive hepatopathy was diagnosed in 60 (29%) patients, who showed more often ascites, lower serum sodium and cholinesterase activity, and higher hepatic injury markers. Mean albumin-bilirubin (ALBI)-score as well as (modified)-model for end-stage liver disease (MELD)-scores were higher in patients with congestive hepatopathy. Median levels of laboratory parameters/scores normalised after HTX, and ascites resolved in most patients with congestive hepatopathy (n = 48/56, 86%). The post-HTX (median follow-up 55.1 months) survival was 87% and liver-related events were rare (3%). Severe ascites, low cholinesterase, and MELD/MELD-XI were associated with ascites persistence/death 1­year after HTX. Age, male sex, and severe ascites were the only independent predictors of post-HTX mortality. Both ALBI and MELD-scores were robust indicators of post-HTX survival when measured 4 weeks after HTX (ALBI log-rank test p < 0.001; MELD log-rank test p = 0.012). CONCLUSION: Congestive hepatopathy and ascites were mostly reversible after HTX. Liver-related scores and ascites improve prognostication in patients after HTX.

Nailfold Videocapillaroscopy for Non-Invasive Assessment of Microcirculation and Prognostic Correlation with Endothelial Dysfunction, Cardiovascular Risk Factors, and Non-HLA Antibodies in Heart Transplant Recipients: A Pilot Study.

Early identification of allograft vasculopathy and the concomitant elimination of adverse risk factors is essential for improving the long-term prognosis of heart transplant (HTx) recipients with underlying cardiovascular disease (CVD). The major aim of this pilot study was to conduct a non-invasive imaging evaluation of the HTx patient microcirculation by employing nailfold video-capillaroscopy (NVC) in a well-characterized patient and control cohort, and to correlate these data with endothelial cell function, accompanied by studies of traditional cardiovascular risk factors and non-HLA antibodies in HTx recipients. Ten patients undergoing HTx (mean age of 38 ± 14 years) were recruited for the study and compared to a control group of 12 well-matched healthy volunteers (mean age 35 ± 5 years) with normal body mass index (BMI). Detailed medical records were collected from all individuals. NVC was performed using CapillaryScope 200 MEDL4N microscope. For functional readout and correlation analysis, endothelial cell network formation in conjunction with measurements of patient serum levels of vascular endothelial growth factor (VEGF) and non-HLA autoantibodies directed against the angiotensin II type-1-receptor (anti-AT1R-Ab), endothelin-1 type-A-receptor (anti-ETAR-Ab), protease-activated receptor-1 (anti-PAR-1-Ab), and VEGF-A (anti-VEGF-A-Ab) were studied. Our NVC analysis found that the average apical loop diameter of nailfold capillaries was significantly increased in HTx recipients (p = 0.001). In addition, HTx patients with more prominent changes in capillaroscopic patterns were characterized by the presence of traditional cardiovascular risk factors, and HTx patients had increased levels of anti-AT1R-ab, anti-ETAR-ab, and anti-VEGF-A-Ab (p = 0.017, p = 0.025, and p = 0.003, respectively). Capillary diameters most strongly correlated with elevated serum levels of troponin T and triglycerides (R = 0.69, p = 0.028 and R = 0.81, p = 0.004, respectively). In conclusion, we found that an abnormal NVC pattern in HTx patients is associated with traditional CVD risk factors and that NVC is a useful non-invasive tool to conveniently monitor changes in the microvasculature of HTx patients.

Biolayer interferometry is insufficiently sensitive for direct measurement of IgM quantity and avidity in Atlantic salmon (Salmo salar) serum.

Quantification of specific antibodies underpins the assessment of adaptive immunity in response to vaccination or infection and is performed by enzyme-linked immunosorbent assay (ELISA). A biolayer interferometry (BLI) assay was recently developed that simultaneously quantifies IgM antibodies and their avidity in giant grouper (Epinephelus lanceolatus) sera and proved to be a robust, repeatable and more high-throughput alternative to ELISA [1]. Here we attempted to optimise a similar single-step BLI assay using an Octet HTX instrument to quantify IgM specific to the hapten 2,4-dinitrophenol (DNP) in serum from Atlantic salmon (Salmo salar) primed and boosted with DNP conjugated to keyhole limpet hemocyanin.