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Ethanol‐induced cardiac fibrosis is mediated by NADPH oxidase (1152.12)
Author(s) -
Mouton Alan,
Walker Morgan,
El Hajj Milad,
Molina Patricia,
Gilpin Nicholas,
Gardner Jason
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1152.12
Subject(s) - nadph oxidase , fibroblast , chemistry , hydroxyproline , fibrosis , oxidative stress , cardiac fibrosis , western blot , superoxide , medicine , endocrinology , nox4 , myocardial fibrosis , biochemistry , in vitro , enzyme , gene
Chronic ethanol (EtOH) abuse leads to cardiomyopathy that is characterized by extensive cardiac fibrosis and dilatation. We hypothesize that EtOH causes cardiac fibrosis by fibroblast activation via NADPH oxidase (NOX)‐induced oxidative stress. Male Sprague‐Dawley rats were intermittently exposed to EtOH vapor for 2 wks (14hr ON/10hr OFF; peak blood alcohol levels of ~200 mg/dL). Time‐matched controls were exposed to room air. Fixed mid‐LV sections stained with picrosirius red were assessed for collagen volume fraction (CVF). To examine the direct effects of EtOH on fibroblasts, isolated adult rat cardiac fibroblasts were treated with EtOH (50mM) for 24 hr, and cell‐conditioned media assayed for hydroxyproline (HPro). Protein expression was determined by Western blot; NOX activity was assessed by NADPH consumption assay; and cellular superoxide production was determined using DHE. Collagen gel contraction assay was used to assess fibroblast activity. In vivo EtOH‐exposure significantly increased LV CVF (1.6% vs 0.9% for control) and NOX‐2 and ‐4 expression (157.0% and 185.6% of control). EtOH significantly increased cardiac fibroblast secretion of collagen (HPro: 1.09±0.09 vs 0.75±0.07 µg/ml for control), and this was prevented by NOX inhibition (DPI; 10µM). EtOH increased fibroblast expression of α‐SMA (150.0% of control) and NOX‐2 (307.2%), but not NOX‐4. EtOH also significantly increased NOX activity (0.39±0.02 vs 0.27±0.00 nmol/mg/min) and superoxide production. EtOH increased gel contraction by fibroblasts (65.4% vs 42.4% control), which was also prevented by NOX inhibition. In conclusion, chronic intermittent EtOH vapor exposure produced cardiac fibrosis, which our data indicate is the result of a NOX‐dependent increase in fibroblast activity and collagen secretion. Grant Funding Source : Supported by an LSUHSC ADACE Pilot Grant (jdg).