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Conditional glucocorticoid receptor expression in the heart induces atrio‐ventricular block
Author(s) -
SainteMarie Yannis,
Cat Aurelie Nguyen Dinh,
Perrier Romain,
Mangin Laurence,
Soukaseum Christelle,
Peuchmaur Michel,
Tronche François,
Farman Nicolette,
Escoubet Brigitte,
Benitah JeanPierre,
Jaisser Frederic
Publication year - 2007
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/fj.07-8357com
Subject(s) - medicine , glucocorticoid receptor , endocrinology , mineralocorticoid receptor , aldosterone , glucocorticoid , qt interval , heart failure , mineralocorticoid , ryanodine receptor 2 , hormone , homeostasis , receptor , ryanodine receptor
Corticosteroid hormones (aldosterone and glucocorticoids) and their receptors are now recognized as major modulators of cardiovascular pathophysiology, but their specific roles remain elusive. Glucocorticoid hormones (GCs), which are widely used to treat acute and chronic diseases, often have adverse cardiovascular effects such as heart failure, hypertension, atherosclerosis, or metabolic alterations. The direct effects of GC on the heart are difficult to evaluate, as changes in plasma GC concentrations have multiple consequences due to the ubiquitous expression of the glucocorticoid receptor (GR), resulting in secondary effects on cardiac function. We evaluated the effects of GR on the heart in a conditional mouse model in which the GR was overex‐pressed solely in cardiomyocytes. The transgenic mice displayed electrocardiogram (ECG) abnormalities: a long PQ interval, increased QRS and QTc duration as well as chronic atrio‐ventricular block, without cardiac hypertrophy or fibrosis. The ECG alterations were reversible on GR expression shutoff. Isolated ventricular cardiomyo‐cytes showed major ion channel remodeling, with decreases in I Na ,I to , and I Kslow activity and changes in cell calcium homeostasis (increase in C al , in Ca 2+ transients and in sarcoplasmic reticulum Ca 2+ load). This pheno‐type differs from that observed in mice overexpressing the mineralocorticoid receptor in the heart, which displayed ventricular arrhythmia. Our mouse model highlights novel effects of GR activation in the heart indicating that GR has direct and specific cardiac effects in the mouse.—Sainte‐Marie, Y., Cat, A. N. D., Perrier, R., Mangin, L., Soukaseum, C., Peuchmaur, M., Tronche, F., Farman, N., Escoubet, B., Benitah, J‐P., Jaisser, F. Conditional glucocorticoid receptor expression in the heart induces atrio‐ventricular block. FASEB J. 21, 3133–3141 (2007)