Daily exposure to chlordecone, an organochlorine pesticide, increases cardiac fibrosis and atrial fibrillation vulnerability.

Chlordecone (CLD) is a carcinogenic organochlorine pesticide. CLD was shown to disturb the activity of cardiac Na 1) Daily ingestion of CLD induces arrhythmogenic cardiac remodeling. 2) A phase of CLD withdrawal can reduce CLD-induced AF susceptibility. Adult male Wistar rats (250 g-275 g) ingested daily-doses of CLD (0 μg/L, 0.1 μg/L, or 1 μg/L) diluted in their quotidian water for 4 weeks. From day (D)29 to D56, all rats received CLD-free water. Vulnerability to AF and cardiac function were evaluated at D28 and D56 by electrophysiological study, echocardiography, and optical-mapping. Levels of genes and proteins related to inflammation, fibrosis, and senescence were quantified by qPCR and immunoassays. Twenty-eight days of CLD exposure were associated with significantly increased AF vulnerability compared to CLD-free rats. Contamination with 1 μg/L CLD significantly reduced atrial conduction velocity (ERP, APD). CLD-weaning normalized food consumption and weight intake. However, after the CLD-withdrawal period of 28 days, AF inducibility, atrial inflammation (IL6, IL1β), and atrial fibrosis (Masson's trichrome staining) remained significantly higher in rats exposed to 1 μg/L CLD compared to 0 μg/L. Prolonged CLD ingestion provokes atrial conduction slowing and increased risk of AF. Although CLD-weaning, some persistent damages occurred in the atrium like atrial fibrosis and atrial senescence signals, which are accompanied by atrial inflammation and arrhythmogenicity.

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Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Roddy Hiram reports financial support was provided by Montreal Heart Institute Foundation. Roddy Hiram reports was provided by Fondation canadienne pour l innovation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.