Myocardial hypoperfusion/reperfusion tolerance with exercise training in hypertension

• Published in: Journal of applied physiology (1985) 2006-02, Vol.100 (2), p.541-547
• Main Authors: Reger, Patricia O, Barbe, Mary F, Amin, Mamta, Renna, Brian F, Hewston, Leigh Ann, MacDonnell, Scott M, Houser, Steven R, Libonati, Joseph R
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blood Pressure; Cardiomegaly - etiology; Cardiomegaly - metabolism; Cardiomegaly - physiopathology; Disease Models, Animal; Exercise; Female; Fundamental and applied biological sciences. Psychology; Heart; Heart Rate; Heart Ventricles - metabolism; HSP72 Heat-Shock Proteins - metabolism; Hypertension; Hypertension - complications; Hypertension - metabolism; Hypertension - physiopathology; Myocardial Contraction - physiology; Myocardial Reperfusion Injury - metabolism; Myocardial Reperfusion Injury - physiopathology; Myocardial Reperfusion Injury - prevention & control; Myocardium - metabolism; Physical Conditioning, Animal - physiology; Proteins; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Rodents; Ventricular Dysfunction, Left - metabolism; Ventricular Dysfunction, Left - physiopathology; Ventricular Dysfunction, Left - prevention & control; Ventricular Pressure
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00350.2005

Departments of 1 Kinesiology, 2 Physiology, 3 Cell Biology, 4 Cardiovascular Research Center, and 5 Department of Physical Therapy, Temple University, Philadelphia, Pennsylvania Submitted 25 March 2005 ; accepted in final form 20 September 2005 The purpose of this study was to examine whether exercise training, superimposed on compensated-concentric hypertrophy, could increase myocardial hypoperfusion-reperfusion (H/R) tolerance. Female Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) (age: 4 mo; N = 40) were placed into a sedentary (SED) or exercise training (TRD) group (treadmill running; 25 m/min, 1 h/day, 5 days/wk for 16 wk). Four groups were studied: WKY-SED ( n = 10), WKY-TRD ( n = 10), SHR-SED ( n = 10), and SHR-TRD ( n = 10). Blood pressure and heart rate were determined, and in vitro isolated heart performance was measured with a retrogradely perfused, Langendorff isovolumic preparation. The H/R protocol consisted of a 75% reduction in coronary flow for 17 min followed by 30 min of reperfusion. Although the rate-pressure product was significantly elevated in SHR relative to WKY, training-induced bradycardia reduced the rate-pressure product in SHR-TRD ( P < 0.05) without an attenuation in systolic blood pressure. Heart-to-body weight ratio was greater in both groups of SHR vs. WKY-SED ( P < 0.001). Absolute and relative myocardial tolerance to H/R was greater in WKY-TRD and both groups of SHR relative to WKY-SED ( P < 0.05). Endurance training superimposed on hypertension-induced compensated hypertrophy conferred no further cardioprotection to H/R. Postreperfusion 72-kDa heat shock protein abundance was enhanced in WKY-TRD and both groups of SHR relative to WKY-SED ( P < 0.05) and was highly correlated with absolute left ventricular functional recovery during reperfusion ( R 2 = 0.86, P < 0.0001). These data suggest that both compensated hypertrophy associated with short-term hypertension and endurance training individually improved H/R and that increased postreperfusion 72-kDa heat shock protein abundance was, in part, associated with the cardioprotective phenotype observed in this study. diastole; heat shock proteins; heart Address for reprint requests and other correspondence: J. R. Libonati, Temple Univ., 122 Pearson Hall, 1800 North Broad St., Philadelphia, PA 19122 (e-mail: jlibonat{at}temple.edu )