title: Persistent fibrosis, hypertrophy and sarcomere disorganisation after endoscopy-guided heart resection in adult Xenopus.
abstract: Models of cardiac repair are needed to understand mechanisms underlying failure to regenerate in human cardiac tissue. Such studies are currently dominated by the use of zebrafish and mice. Remarkably, it is between these two evolutionary separated species that the adult cardiac regenerative capacity is thought to be lost, but causes of this difference remain largely unknown. Amphibians, evolutionary positioned between these two models, are of particular interest to help fill this lack of knowledge. We thus developed an endoscopy-based resection method to explore the consequences of cardiac injury in adult Xenopus laevis. This method allowed in situ live heart observation, standardised tissue amputation size and reproducibility. During the first week following amputation, gene expression of cell proliferation markers remained unchanged, whereas those relating to sarcomere organisation decreased and markers of inflammation, fibrosis and hypertrophy increased. One-month post-amputation, fibrosis and hypertrophy were evident at the injury site, persisting through 11 months. Moreover, cardiomyocyte sarcomere organisation deteriorated early following amputation, and was not completely recovered as far as 11 months later. We conclude that the adult Xenopus heart is unable to regenerate, displaying cellular and molecular marks of scarring. Our work suggests that, contrary to urodeles and teleosts, with the exception of medaka, adult anurans share a cardiac injury outcome similar to adult mammals. This observation is at odds with current hypotheses that link loss of cardiac regenerative capacity with acquisition of homeothermy.
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Lindsey
authors.identifier: http://orcid.org/0000-0002-0735-6582
authors.initials: L
authors.lastname: Marshall
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Vivien
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Girardot
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Louise
authors.initials: L
authors.lastname: Péricard
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Demeneix
authors.affiliation: Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, UMR CNRS 7221, Muséum National d'Histoire Naturelle, Sorbonne Université, Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Coen
authors.affiliation: Ménagerie du Jardin des Plantes, Muséum National d'Histoire Naturelle, Paris, France.
authors.forename: Norin
authors.initials: N
authors.lastname: Chai
mesh_terms: D000671:Amputation, Surgical / Q000009:adverse effects; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D004724:Endoscopy; D005260:Female; D005355:Fibrosis; D012518:Sarcomeres / Q000378:metabolism / Q000473:pathology*; D025321:Surgery, Computer-Assisted / Q000009:adverse effects*; D013903:Thoracic Surgery; D013997:Time Factors; D015854:Up-Regulation; D014982:Xenopus laevis
chemical_list: D015415:Biomarkers