Published Online
on September 17, 2008

A more recent version of this article appeared on November 1, 2008

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Original Article

Myocardial Alterations in Senescent Mice and Effect of Exercise Training: A Strain Rate Imaging Study

Genevieve Derumeaux^1,3; Fumito Ichinose²; Michael J Raher²; John G Morgan²; Tereza Coman²; Candace Lee²; Jose Maria Cuesta²; Hélène Thibault²; Kenneth D. Bloch²; Michael H. Picard² and Marielle Scherrer-Crosbie²

¹ Université Claude Bernard, Lyon, France;
² Massachusetts General Hospital, Boston, MA

³ E-mail: genevieve.derumeaux{at}chu-lyon.fr

Background—Aging is accompanied by an alteration in myocardial contractility. However its noninvasive detection is difficult. The effect of chronic exercise on this decrease is unknown. Murine models of senescence are increasingly used to test therapies in aging. We tested whether strain rate imaging (SRI) detected left ventricular (LV) systolic dysfunction in aging mice and was able to assess a potential improvement after exercise.

Methods and Results—Young (3weeks), adult (2-3 months) and old (6-18 months) C57BL6 male mice underwent echocardiograms with SRI, either in sedentary conditions or before, 2 weeks and 4 weeks after chronic swimming. Hemodynamic parameters of LV function including maximal and end-systolic elastance were obtained before sacrifice. LV fibrosis was measured using Sirius Red staining. Conventional echocardiography was unable to detect LV systolic dysfunction in old mice whereas both systolic strain rate and load-independent hemodynamic parameters such as preload recruitable stroke work and end-systolic elastance were significantly decreased. Both strain rate and load-independent hemodynamic parameters normalized after four weeks of exercise. Both endocardial and epicardial fibrosis were increased in the LV of aging mice. Endocardial fibrosis decreased in exercised aged mice.

Conclusions—Strain rate noninvasively detects LV systolic dysfunction associated with aging in mice whereas conventional echocardiography does not. Chronic exercise normalizes LV systolic function and decreases fibrosis in old mice. Strain rate imaging in mice may be a useful tool to monitor the effect of new therapeutic strategies preventing the myocardial dysfunction associated with aging.

Key Words: aging • echocardiography • exercise

Related Article

Myocardial Alterations in Senescent Mice and Effect of Exercise Training: A Strain Rate Imaging Study

Geneviève Derumeaux, Fumito Ichinose, Michael J. Raher, John G. Morgan, Tereza Coman, Candace Lee, Jose Maria Cuesta, Hélène Thibault, Kenneth D. Bloch, Michael H. Picard, and Marielle Scherrer-Crosbie
Circ Cardiovasc Imaging 2008 1: 227-234. [Abstract] [Full Text] [PDF]