Velloso EP, Pimentel RL, Braga JF, Cabral ACV, Reis ZSN, Bader M, Santos RAS, Wallukat G. Identification of a Novel Agonist-Like Autoantibody in Preeclamptic Patients.
Am J Hypertens 2016;
29:405-12. [PMID:
26158852 DOI:
10.1093/ajh/hpv099]
[Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/08/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND
Recent studies have shown that preeclampsia (PE) is associated with the presence of autoantibodies (AABs) that activate the angiotensin II AT1 receptor, which could contribute to many of the symptoms of PE.
METHODS
To investigate the frequency and the targets of AABs in preeclamptic women (31 cases) and healthy pregnant normotensive women (29 cases) in Brazil, antibodies from serum samples were detected by a bioassay using spontaneously beating neonatal rat cardiomyocytes in culture. In the cardiomyocytes, the agonistic AABs induce a positive or negative chronotropic response, mimicking the corresponding receptor agonists. The specificity of the AAB response was identified by specific receptor antagonists.
RESULTS
Thirty preeclamptic patients (97%) presented AABs against the angiotensin II AT1 receptor. The agonistic effect of the AAB was blocked by irbesartan and neutralized by a peptide corresponding to the second extracellular loop of this receptor. Strikingly, we discovered that all sera from the severe preeclamptic patients (16 cases) contained a novel agonist-like AAB directed against the endothelin-1 ETA receptor in addition to the AABs against the angiotensin II AT1 receptor. This AAB was selectively blocked by the antagonist BQ-123, antagonized by the protein kinase C (PKC) inhibitor Calphostin C and neutralized by peptides corresponding to the second extracellular loop of the endothelin-1 ETA receptor subtype.
CONCLUSIONS
We described, for the first time, the presence of endothelin-1 ETA receptor AABs in PE. Our results suggest that the presence of both agonistic AABs may be involved in the pathogenesis of severe PE.
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