title: Interactions between cardiac cells enhance cardiomyocyte hypertrophy and increase fibroblast proliferation.
abstract: In cardiac hypertrophy, both excessive enlargement of cardiac myocytes (CMs) and progressive fibrosis are known to occur simultaneously. To investigate the nature of interactions between ventricular CMs and cardiac fibroblasts (CFs) in these conditions, we have established a "dedifferentiated model" of adult murine CMs in coculture with CFs. In such a model, which is recognized to study cardiac cell hypertrophy in vitro, dedifferentiated CMs in culture and in coculture were characterized by immunopositive staining to ANP (atrial natriuretic peptide) and beta-myosin heavy chain (beta-MHC). The results confirm that ANP secretion by CMs was significantly increased during the cultures. The increase size of cultured CMs was significantly higher in CM/CF cocultures than in CM cultures which was also observed when CMs were cultured with fibroblast conditioned medium (FCM). In addition, fibroblast proliferation studies showed that CMs favored fibroblast adhesion and/or growth at the beginning of the coculture and fibroblast proliferation throughout the time course of the coculture. Furthermore, a significant level of interleukin-6 (IL-6) production was detected by ELISA in CM/CF cocultures. A similar higher increase was observed when CMs were cultured in the presence of FCM. These results demonstrate that CFs enhance myocyte hypertrophy and that CMs regulate fibroblast adhesion and/or proliferation, suggesting a paracrine interaction between CMs and CFs which could involve IL-6.
authors.affiliation: Laboratoire de Physiologie et Physiopathologie Cardiaques, UMR 6187 CNRS-Université de Poitiers, Poitiers, Cedex, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Fredj
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Bescond
authors.forename: Claire
authors.initials: C
authors.lastname: Louault
authors.forename: Daniel
authors.initials: D
authors.lastname: Potreau
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D015415:Biomarkers; D006332:Cardiomegaly; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D006984:Hypertrophy; D051379:Mice; D009206:Myocardium / Q000166:cytology* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D024723:Ventricular Myosins / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016207:Cytokines; D009320:Atrial Natriuretic Factor; D024723:Ventricular Myosins; D018995:Myosin Heavy Chains