Combined Heart-Liver and Domino Liver Transplantation in Familial Amyloidosis

Background Combined heart-liver transplantation (CHLT) is the only curative option for patients with concomitant pathology affecting the heart and liver. In some cases, the native livers of familial amyloidosis (FA) patients may be suitable for domino transplantation into other recipients. Methods Retrospective analysis (2013 to 2019) of all CHLT at our center was performed. Continuous data were presented as mean with standard deviation and discrete variables as percentages. Results Familial amyloidosis was the indication for CHLT in 5 out of 6 patients. The mean recipient age was 55 ± 5.62 years. Two patients were bridged with total artificial heart. The mean model for end-stage liver disease score at transplant was 17.17 ± 3.7. Two explanted livers were used for transplantation in a domino fashion. The median intensive care and hospital stays were 5.5 and 19 days, respectively. Complications included renal failure (1), groin abscess (1), pulmonary embolism (1), and cardiac rejection (1). Patient and graft survival for both organs was 100% at a median follow-up of 59 (range 20-76) months. Discussion Combined heart-liver transplantation for FA achieves excellent outcomes. The possible use of livers explanted from patients with FA for domino liver transplantation can contribute to the liver donor pool.

Corelattions Between CD31, CD68, MMP-2 and MMP-9 Expression in Allograft Cardiac Rejection – Immunohistochemical Study

Introduction. The cardiac allograft rejections from the post-transplant period are attributable to the acute cellular rejection monitored by multiple endomyocardial biopsies. Compared to this, humoral rejection remains a matter of debate, with multiple therapeutic strategies, poor prognosis, and persisting uncertainty about diagnostic criteria. Acute allograft rejection is associated with significant modifications of the extracellular matrix compartment mainly regulated by matrix metalloproteinases (MMPs). In this context, the aim of this study was to evaluate the expression of MMP-2 and -9 and CD31, CD68 (endothelial and histiocytic markers) and the correlations between them using immunohistochemistry, in patients with cardiac allografts. Materials and methods. Tissue fragments were obtained by endomyocardial biopsy from 5 patients with allograft heart transplant, 2 in the medium post-transplant phase and 2 in late phase. After identifying and characterizing the morphological context the probes were processed by standard immunohistochemical technique using anti-MMP-2 and anti-MMP-9 antibodies (Santa Cruz Biotechnology, Inc.) and anti-CD31, anti-CD68 antibodies (Sigma). The samples were examined using the Olympus BX40 microscope with an Olympus E330 camera attached. Results and discussions. Sample examination revealed in all 4 cases the lack of IR (-) for CD31 and weak IR (+) for CD68 compared to MMPs, where we found moderate IR (++) for MMP-9 and weak IR (+) for MMP-2. These aspects complets the histological lesional aspects of these cases, indicating the lack of acute rejection. In conclusion, CD31 and CD68 IR correlated with MMPs IR (especially MMP-9) appear to represent predictive markers for cardiac allograft rejection and require further studies.

P4734Electron microscopy reveals evidence of perinuclear clustering of mitochondria in cardiac biopsy proven allograft rejection

Background Despite improved efficacy of immunosuppression therapy, allograft rejection continues to be a significant risk, especially early after transplantation. Endomyocardial biopsy (EMB) is the standard tool with a recognized role in the surveillance of posttransplant cardiac rejection and is based on optical microscopy analysis. However, this method presents technical limitations. Purpose In this work we focus on the analysis of new ultrastructural findings in cardiac biopsy specimens. Methods This study include heart transplanted patients from a single center who were referred for EMB as a scheduled routine screening. Participants were divided into 2 groups: patients transplanted without allograft rejection (n=5), and patients with biopsy-proven allograft rejection (n=5). Rejection episodes were assessed according to the International Society for Heart and Lung Transplantation (ISHLT) consensus report. Results We detected by electronic microscopy a significative increase in the number of mitochondria (p<0.0001) and dense bodies in the rejection group (p<0.05). But the most significative finding was the presence of local accumulations of mitochondria close to the nuclear envelope, pressing and shaping the morphology of this membrane in all rejection samples. We found these perinuclear clustering of mitochondria in a 68±27% of the total cardiac nucleus observed from rejection samples. We not observed this phenomenon in non-rejection samples, thus reflecting an excellent sensitivity and specificity. Perinuclear clustering of mitochondria Conclusion We observed by electron microscopy a specific phenomenon, perinuclear clustering of mitochondria, in endomyocardial biopsies from patients with cardiac rejection that affects to the architecture of the nuclear membrane. This ultrastructural approach might complement and improve the diagnosis of rejection. Acknowledgement/Funding National Institute of Health [PI16/01627, PI17/01925, PI17/01232], “Consorcio Centro de Investigaciόn Biomédica en Red, M.P.”, and FEDER

Circulating Sphingosine-1-Phosphate as A Non-Invasive Biomarker of Heart Transplant Rejection

Accumulating evidence has confirmed that the expression of sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) is downregulated in heart failure and cardiac allograft rejection. Although many SERCA2a-related genes and proteins involved in the regulation of myocardial Ca2+ fluxes have been explored, its related metabolites remain poorly studied. Our main objective was to identify circulating SERCA2a-related metabolites altered in cardiac allograft rejection and to determine whether these could serve as non-invasive biomarkers. Sixty plasma samples from adult heart transplant were included in a metabolomic analysis. Sphingosine-1 phosphate (S1P), metabolite closely related with SERCA, were increased in patients with cardiac rejection (p < 0.0001). S1P discriminated between patients with and without rejection: normal grafts vs. all rejecting grafts (AUC = 0.911, p < 0.0001), normal grafts vs. Grade 1 R (AUC = 0.819, p < 0.01), Grade 2 R (AUC = 0.911, p < 0.0001), Grade 3 R (AUC = 0.996, p < 0.0001). In addition, we found changes in key enzymes and receptors of S1P pathway analysed on explanted hearts from heart failure patients. This preliminary study reveals that circulating S1P determination could be a novel approach to detect cardiac rejection, showing a robust capability for detection that improves gradually with the severity of rejection. These alterations could be relevant to better understand the involvement of calcium regulation on the pathophysiology of rejection.