Insulin-like growth factor-1 overexpression in cardiomyocytes diminishes ex vivo heart functional recovery after acute ischemia

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Title Insulin-like growth factor-1 overexpression in cardiomyocytes diminishes ex vivo heart functional recovery after acute ischemia
Author Prele, Cecilia M.; Reichelt, Melissa E.; Mutsaers, Steven E.; Davies, Marilyn; Delbridge, Lea M.; Headrick, John Patrick; Rosenthal, Nadia; Bogoyevitch, Marie A.; Grounds, Miranda D.
Journal Name Cardiovascular Pathology
Year Published 2012
Place of publication United States
Publisher Elsevier
Abstract BACKGROUND: Acute insulin-like growth factor-1 administration has been shown to have beneficial effects in cardiac pathological conditions. The aim of the present study was to assess the structural and ex vivo functional impacts of long-term cardiomyocyte-specific insulin-like growth factor-1 overexpression in hearts of transgenic αMHC-IGF-1 Ea mice. METHODS: Performance of isolated transgenic αMHC-IGF-1 Ea and littermate wild-type control hearts was compared under baseline conditions and in response to 20-min ischemic insult. Cardiac desmin and laminin expression patterns were determined histologically, and myocardial hydroxyproline was measured to assess collagen content. RESULTS: Overexpression of insulin-like growth factor-1 did not modify expression patterns of desmin or laminin but was associated with a pronounced increase (∼30%) in cardiac collagen content (from ∼3.7 to 4.8 μg/mg). Baseline myocardial contractile function and coronary flow were unaltered by insulin-like growth factor-1 overexpression. In contrast to prior evidence of acute cardiac protection, insulin-like growth factor-1 overexpression was associated with significant impairment of acute functional response to ischemia-reperfusion. Insulin-like growth factor-1 overexpression did not modify ischemic contracture development, but postischemic diastolic dysfunction was aggravated (51±5 vs. 22±6 mmHg in nontransgenic littermates). Compared with wild-type control, recovery of pressure development and relaxation indices relative to baseline performance were significantly reduced in transgenic αMHC-IGF-1 Ea after 60-min reperfusion (34±7% vs. 62±7% recovery of +dP/dt; 35±11% vs. 57±8% recovery of -dP/dt). CONCLUSIONS: Chronic insulin-like growth factor-1 overexpression is associated with reduced functional recovery after acute ischemic insult. Collagen deposition is elevated in transgenic αMHC-IGF-1 Ea hearts, but there is no change in expression of the myocardial structural proteins desmin and laminin. These findings suggest that sustained cardiac elevation of insulin-like growth factor-1 may not be beneficial in the setting of an acute ischemic insult.
Peer Reviewed Yes
Published Yes
Alternative URI
Volume 21
Issue Number 1
Page from 17
Page to 27
ISSN 1054-8807
Date Accessioned 2011-04-29; 2012-08-08T23:34:11Z
Date Available 2012-08-08T23:34:11Z
Research Centre Griffith Health Institute; Heart Foundation Research Centre
Faculty Griffith Health Faculty
Subject Cardiology (incl Cardiovascular Diseases)
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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