The Role of Functional Active Anti-Angiotensin-Receptor 1 (ATR1)- and Anti-Endothelin-Receptor A (ETRA)-Antibodies and Autoreactive T Cells in Cardiomyopathy
The Role of Functional Active Anti-Angiotensin-Receptor 1 (ATR1)- and Anti-Endothelin-Receptor A (ETRA)-Antibodies and Autoreactive T Cells in Cardiomyopathy
The study aims 1) to determine autoantibody titers against the AGTR1 receptor and against the ETA receptor, 2) to characterize cytokine expression profiles of heart-specific activated T cells in patients with systolic heart failure. Auto-antibody titers and specific cytokine expression profiles in heart-specific activated T cells will then be correlated with heart failure progression and outcome.
AIM OF THE STUDY 1.1. Background Progressive interstitial fibrosis parallels pathological remodeling in the failing heart. This is particularly the case in patients with post-inflammatory dilated cardiomyopathy, but is also observed in ischemic and hypertensive heart disease. Both, Angiotensin II (AngII) and Endothelin-1 (ET1) induce the formation of the profibrotic cytokine TGFβ and promote fibrosis. From this point of view, it is not surprising that blocking the Renin-Angiotensin-Aldosterone-System (RAAS) evolved as key strategy to slow heart failure progression. Furthermore, recent data also points to an important role of Angiotensin II signaling in heart failure with preserved ejection fraction. In animal models, blocking the effect of AngII or ET1 reduces fibrotic remodeling following myocardial ischemia or in pulmonal hypertension. In line with these findings, we found no evidence of fibrotic remodeling in AGTR1-/- mice who recovered from acute myocarditis. Nevertheless, RAAS blockade is not efficient enough to completely prevent heart failure progression or even rapid deterioration in subgroups of the affected patients. Only recently, Riemekasten et al demonstrated that auto-antibodies against AGTR1 and ETAR are increased in systemic sclerosis and associated with increased pulmonary hypertension and lung fibrosis (2). Moreover, these auto-antibodies were shown to be functional active and to induce downstream expression of TGFβ -mRNA.
Anti-AGTR1-Ab and Anti-ETAR-Ab might therefore directly promote fibrosis through activation of AGTR1 and ETAR. Furthermore, auto-reactive T-cells to the myosin heavy chain (MyHC) of the heart muscle were demonstrated to play an important role in both the initial inflammation during myocarditis as well as the progression of inflammation.
1.2. Rationale for the current study Cardiac autoantibody titers are generally elevated in patients after myocardial infarction or suffering from systolic heart failure. In addition, we found experimental evidence for a critical role of AngII signaling in the development of cardiac fibrosis. We hypothesize that auto-immunological effects in general, and Anti-AGTR1-Ab, Anti- ETAR-Ab and auto-reactive T-cells in particular, are important and so far widely underestimated in the pathogenesis of cardiomyopathies and that they interfere with evidence based treatment approaches.
1.3 Aims The objectives of this study are to
STUDY DESIGN Prospective pilot study.
PARTICITPANT ENTRY 3.1. Pre---registration evaluation Patients with cardiomyopathy and heart failure for 6 months or more will be recruited at the GZO Spital Wetzikon during ambulatory visits.
EFFICACY AND SAFETY VARIABLES 4.1. Efficacy variables and examinations 4.1.1 non---study specific variables and examinations Medical history
Transthoracal echocardiography (TTE) TTE will be performed by a cardiologist. The following parameters will be recorded:
4.1.2 Study specific variables and examinations Determinations of Anti-AGTR1-AB and Anti-ETRA-AB Concentrations of Anti-AGTR1-AB and Anti-ETRA-AB will be measured using commercially available ELISA-Kits according to manufactures protocol (Celltrend, Luckenwalde, Germany).
Evaluation of auto-reactive T-Cells Auto-reactive T-cells will be isolated from patient blood and analysed as described for organ-specificity (cMET+), for their reactivity against cardiac self-antigens and for their cytokine expression profile.
ASSESSMENT AND FOLLOW---UP The investigations during the visit are described in paragraph 4. The assessment are performed during the initial visit, at 4 months, and at 12 months.
STATISTICS AND DATA ANALYSIS As this is a pilot study and no published data on the observed parameters in cardiomyopathies are available, no power analysis was performed. Groups will be compared using ANOVA. Statistical significance will be assumed at a probability of p < 0.05.
REGULATORY ISSUES 7.1 Ethic approval The study will be conducted according to the current declaration of Helsinki, the Good Clinical Practice-guidelines and Swiss regulatory authority´s requirements. The study has been approved by the KEK (local ethics committee).
7.2 Consent Written consent will be sought from participants only after full explanation of the study and time allowed for consideration. The right of the participant to refuse to participate without giving reasons will be respected. If the participant withdrawls his/her consent, data collected to the date of the withdrawal will be used.
7.3 Confidentiality All study personnel will preserve the confidentiality of participants taking part in the study.
7.4 Insurance Insurance is covered by "Zurich Versicherungsgesellschaft AG" for GZO Spital Wetzikon.
QUALITY CONTROL 8.1 Audits The investigators welcome audits by regulatory bodies to ensure adherence to GCP and regulatory requirements.
8.2 Data management A designated research nurse and/or research fellow will be responsible for data collection and data management.
8.3 Data privacy Access to personal data of participants is strictly limited to the investigators aforementioned. Raw data will be archieved for at least 10 years. Blood samples willbe analysed at the Center for Molecular Cardiology of the University of Zurich in the group for cardioimmunology and destroyed after definitive analysis. Blood sample collection will be done at GZO Spital Wetzikon. The blood samples will be anonymised directly after collection. All data sheets, blood samples and data fromanalysis will be anonymised to a two-digit code. The key to match the two-digit-code to the personal data of the patient will be stored in a separate, password-protected data base. Only the principal investigator and investigator Dr. med. Nazmi Krasniqi will have access to this data base.
Inclusion Criteria:
Exclusion Criteria: