Gender and post-ischemic recovery of hypertrophied rat hearts

• Main Authors: Popov Kirill M, Dunaway George A, Keller Angelica, Leong Hon S, Antler Christine, Parsons Hannah, Wambolt Richard B, Saeedi Ramesh, Allard Michael F
• Format: Article
• Language: English
• Published: BMC 2006-03-01
• Series: BMC Cardiovascular Disorders
• Online Access: http://www.biomedcentral.com/1471-2261/6/8

<p>Abstract</p> <p>Background</p> <p>Gender influences the cardiac response to prolonged increases in workload, with differences at structural, functional, and molecular levels. However, it is unknown if post-ischemic function or metabolism of female hypertrophied hearts differ from male hypertrophied hearts. Thus, we tested the hypothesis that gender influences post-ischemic function of pressure-overload hypertrophied hearts and determined if the effect of gender on post-ischemic outcome could be explained by differences in metabolism, especially the catabolic fate of glucose.</p> <p>Methods</p> <p>Function and metabolism of isolated working hearts from sham-operated and aortic-constricted male and female Sprague-Dawley rats before and after 20 min of no-flow ischemia (N = 17 to 27 per group) were compared. Parallel series of hearts were perfused with Krebs-Henseleit solution containing 5.5 mM [5-³H/U-¹⁴C]-glucose, 1.2 mM [1-¹⁴C]-palmitate, 0.5 mM [U-¹⁴C]-lactate, and 100 mU/L insulin to measure glycolysis and glucose oxidation in one series and oxidation of palmitate and lactate in the second. Statistical analysis was performed using two-way analysis of variance. The sequential rejective Bonferroni procedure was used to correct for multiple comparisons and tests.</p> <p>Results</p> <p>Female gender negatively influenced post-ischemic function of non-hypertrophied hearts, but did not significantly influence function of hypertrophied hearts after ischemia such that mass-corrected hypertrophied heart function did not differ between genders. Before ischemia, glycolysis was accelerated in hypertrophied hearts, but to a greater extent in males, and did not differ between male and female non-hypertrophied hearts. Glycolysis fell in all groups after ischemia, except in non-hypertrophied female hearts, with the reduction in glycolysis after ischemia being greatest in males. Post-ischemic glycolytic rates were, therefore, similarly accelerated in hypertrophied male and female hearts and higher in female than male non-hypertrophied hearts. Glucose oxidation was lower in female than male hearts and was unaffected by hypertrophy or ischemia. Consequently, non-oxidative catabolism of glucose after ischemia was lowest in male non-hypertrophied hearts and comparably elevated in hypertrophied hearts of both sexes. These differences in non-oxidative glucose catabolism were inversely related to post-ischemic functional recovery.</p> <p>Conclusion</p> <p>Gender does not significantly influence post-ischemic function of hypertrophied hearts, even though female sex is detrimental to post-ischemic function in non-hypertrophied hearts. Differences in glucose catabolism may contribute to hypertrophy-induced and gender-related differences in post-ischemic function.</p>