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Identification and characterization of trajectories of cardiac allograft vasculopathy after heart transplantation

5/4/2020

 
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Every year, tens of thousands of deaths are due to end-stage heart failure in Europe and in the US combined. Heart transplantation is the ultimate treatment, but its number is dramatically limited due to the shortage of organs in those countries. 
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​In the same time, the chances of survival beyond one year after transplantation have remained unchanged in recent years, despite significant progress in immunosuppressive therapy and patient care.
One of the most common reasons for long-term graft failure and patient death is an accelerated form of coronary artery disease called cardiac allograft vasculopathy. It is a frequent complication that affects up to half of patients within 10 years following heart transplantation. Yet, until now, little has been known about the different evolutive profiles of cardiac allograft vasculopathy and their risk factors.

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Building a tissue-based molecular diagnostic system in heart transplant rejection: The heart Molecular Microscope Diagnostic (MMDx) System.

11/9/2017

 
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Abstract
Halloran PF, Potena L, Van Huyen JD, Bruneval P, Leone O, Kim DH, Jouven X, Reeve J, Loupy A.

The emergence of molecular systems offers opportunities for improving the assessment of rejection in heart transplant biopsy specimens. The present study developed a microarray-based system for assessing heart transplant endomyocardial biopsy (EMB) specimens.
We analyzed 331 protocol or for-cause EMB specimens from 221 subjects in 3 centers (Edmonton, Bologna, and Paris). Unsupervised principal component analysis (PCA) and archetype analysis used rejection-associated transcripts (RATs) shown in kidney transplants to be associated with antibody-mediated rejection (ABMR) or T cell-mediated rejection (TCMR), or both. To compare EMB specimens to kidney biopsy specimens, rejection status in both was simplified to TCMR, ABMR, or no rejection.
The pattern of RAT expression was similar in EMB and kidney specimens, permitting use of RATs to assign scores and group ("cluster") membership to each EMB, independent of histology. Three clusters emerged in EMB specimens, similar to kidney specimens: TCMR, ABMR, and no rejection. This permitted each EMB specimen to be given 3 scores and assigned to 1 cluster by its highest score. There was significant agreement between molecular phenotype-archetype scores or clusters-and both histologic diagnoses and donor-specific antibody. Area under curve estimates for predicting histologic TCMR, ABMR, and no rejection by molecular assessment were lower in EMB specimens than in kidney specimens, reflecting more uncertainty in EMB specimens, particularly in histologic diagnosis of TCMR.
Rejection-associated transcripts can be used to estimate the probability of TCMR and ABMR in heart transplant specimens, providing a new dimension to improve the accuracy of diagnoses and an independent system for recalibrating the histology guidelines.
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J Heart Lung Transplant. 2017 Nov;36(11):1192-1200
PMID:28662985

European Society of Organ Transplantation (ESOT) Congress 2017 - Our abstracts

9/24/2017

 
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​Sunday September 24, 2017

1/ MOLECULAR CORRELATES OF ENDOTHELIAL MTOR ACTIVATION IN HEART TRANSPLANT RECIPIENTS
Session: “ Basic and translational immunology” (17:45 to 18:45)
Location: Room 118 + 119 – 18:29 

M Racapé, A Loupy, J Reeve, J Venner , R Guillemain, L Hidalgo, C Lefaucher, X Jouven, P Bruneval, J Duaong Van Huyen, P Halloran 
Background
The detection of phosphorylated effectors of the mTOR pathway such as phosphorylated-S6RP in endothelial cells by immunohistochemistry (IHC) has been associated with Antibody-Mediated allograft Rejection (AMR). The aim of this study was to evaluate the molecular phenotype related to the endothelial detection of pS6RP in heart transplant recipients.
Methods
This case-control study included 41 heart transplant patients from four French referral centers with biopsy proven antibody-mediated rejection (pAMR+) and a matched control group of 30 patients without rejection (pAMR0) based on the updated ISHLT classification. From these patients, 94 endomyocardial biopsies (EMB) had adequate material for microarray analysis and endothelial expression analysis of pS6RP by IHC. We also determined the allograft gene expression profile using the ABMR molecular score in addition to pathogenesis-based transcripts reflecting endothelial activation (DSAST and ENDAT), macrophage burden (QCMAT), gamma-interferon response (GRIT) and NK-cell burden (NKB) (http://atagc.med.ualberta.ca).
Results
Among the 94 EMBs included in the main analyses, 50 were pAMR+ (53.2%) and 44 (46.8%) were pAMR0 normal EMBs. Endothelial expression of pS6RP was observed in 27/50 (54%) of pAMR+ biopsies and 12 out of 44 normal biopsies (27.3%, Fischer's exact: p=0.012). As compared with biopsies without pS6RP labeling, biopsies with pS6RP staining showed increased expression of DSAST (Mann-Whitney: p<0.0001), ENDAT (p=0.0009), QCMAT (p=0.0046), NKB (p=0.0001), GRIT (p=0.0008) and increased ABMR molecular score reflecting AMR injury (p=0.0001).
Conclusion
Endothelial activation of mTOR pathway is associated with AMR and increased expression in transcripts reflecting endothelial activation, macrophage burden, microcirculation and NK burden. Our results suggest the importance of the mTOR pathway activation in AMR injury and the potential interest of using mTOR inhibitors in this setting.

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Molecular Assessment of Microcirculation Injury in Formalin-Fixed Human Cardiac Allograft Biopsies With Antibody-Mediated Rejection.

2/17/2017

 
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Am J Transplant. 2017 Feb;17(2):496-505.
PMID: 27401781

Abstract
B. Afzali, E. Chapman,  M. Racapé, B. Adam,  P. Bruneval, F. Gil, D. Kim, L. Hidalgo, P. Campbell, B. Sis, J. P. Duong Van Huyen, M. Mengel.
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Precise diagnosis of antibody-mediated rejection (AMR) in cardiac allograft endomyocardial biopsies (EMBs) remains challenging. This study assessed molecular diagnostics in human EMBs with AMR. A set of 34 endothelial, natural killer cell and inflammatory genes was quantified in 106 formalin-fixed, paraffin-embedded EMBs classified according to 2013 International Society for Heart and Lung Transplantation (ISHLT) criteria. The gene set expression was compared between ISHLT diagnoses and correlated with donor-specific antibody (DSA), endothelial injury by electron microscopy (EM) and prognosis. Findings were validated in an independent set of 57 EMBs. In the training set (n = 106), AMR cases (n = 70) showed higher gene set expression than acute cellular rejection (ACR; n = 21, p < 0.001) and controls (n = 15, p < 0.0001). Anti-HLA DSA positivity was associated with higher gene set expression (p = 0.01). Endothelial injury by electron microscopy strongly correlated with gene set expression, specifically in AMR cases (r = 0.62, p = 0.002). Receiver operating characteristic curve analysis for diagnosing AMR showed greater accuracy with gene set expression (area under the curve [AUC] = 79.88) than with DSA (AUC = 70.47) and C4d (AUC = 70.71). In AMR patients (n = 17) with sequential biopsies, increasing gene set expression was associated with inferior prognosis (p = 0.034). These findings were confirmed in the validation set. In conclusion, biopsy-based molecular assessment of antibody-mediated microcirculation injury has the potential to improve diagnosis of AMR in human cardiac transplants.

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The XIIIth Banff Conference on Allograft Pathology: The Banff 2015 Heart Meeting Report: Improving Antibody-Mediated Rejection Diagnostics: Strengths, Unmet Needs, and Future Directions.

10/5/2015

 
Abstract
Bruneval P, Angelini A, Miller D, Potena L, Loupy A, Zeevi A, Reed EF, Dragun D, Reinsmoen N, Smith RN, West L, Tebutt S, Thum T, Haas M, Mengel M, Revelo P, Fedrigo M, Duong Van Huyen JP, Berry GJ.
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​The 13th Banff Conference on Allograft Pathology was held in Vancouver, British Columbia, Canada from October 5 to 10, 2015. The cardiac session was devoted to current diagnostic issues in heart transplantation with a focus on antibody-mediated rejection (AMR) and small vessel arteriopathy. Specific topics included the strengths and limitations of the current rejection grading system, the central role of microvascular injury in AMR and approaches to semiquantitative assessment of histopathologic and immunophenotypic indicators, the role of AMR in the development of cardiac allograft vasculopathy, the important role of serologic antibody detection in the management of transplant recipients, and the potential application of new molecular approaches to the elucidation of the pathophysiology of AMR and potential for improving the current diagnostic system. Herein we summarize the key points from the presentations, the comprehensive, open and wide-ranging multidisciplinary discussion that was generated, and considerations for future endeavors.

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Am J Transplant. 2017 Jan;17(1):42-53.
PMID: 
27862968
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Figure 3: Spectrum of cardiac allograft vasculopathy (from epicardial arteries to myocardial capillaries). (A) Allograft epicardial coronary artery showing intimal and adventitial inflammation (hematoxylin and eosin [H&E], ×100). (B) Allograft epicardial coronary artery showing intimal fibrosis with shallow fibrin thrombus at the luminal aspect and some entrapped fibrin deeper in the intimal wall (arrows) (H&E, ×20). (C) Allograft epicardial coronary artery with less intimal thickening but dramatic adventitial lymphoid aggregate (asterisk) (H&E, ×20). (D) Allograft epicardial coronary artery showing advanced narrowing with a slit‐like lumen; there is very little outward remodeling of the vessel wall (H&E, ×40). (E) Allograft endomyocardial biopsy photomicrograph after computer‐assisted image analysis for capillary density. This case showed reduced capillaries (CD34 stain, ×200) (MVD, microvascular density). (F) Allograft endomyocardial biopsy photomicrograph after computer‐assisted image analysis for capillary density. This case showed preserved capillary density (CD34 stain, ×200). (G) and (H) Electron photomicrographs of allograft myocardium showing an interstitial capillary with basement membrane multilayering (arrows) (original ×4000 and ×10 000).

2015 BANFF/CST, October 5-10, 2016 | Vancouver, BC

10/5/2015

 
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Conference Organizing Committee
Co-Directors
Kim Solez
Lorraine Racusen

2015 BAnff/CST Meeting, Organizing Corporation (MOC)
John Gill
Michael Mengel
Anthony Jevnikar
David Rush
Denis Glotz
Kim Solez
Marcelo Cantarovich
Mark Haas
Steven Paraskevas

Local Organizer
Michael Mengel

Conference Coordinators
Korey Fung
Rongjia Sheldon
Aditi Raghuveer
Preeti Kuttikat

Programm Committee
Alexandre Loupy, chair
Christopher Bellamy
Carmen Lefaucheur
Mark Hass
Banu Sis
Kathryn Tinckham
Candice Roudfosse
Cinthia Beskox Drachenberg
Carol Farver
W. Dean Wallace 
Linda C cendales
Lynn Cornell
Patrick Bruneval
​2015 BANFF/CST, October 5-10, 2016 | Vancouver, BC

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