Myocardial energetics is not compromised during compensated hypertrophy in the Dahl salt-sensitive rat model of hypertension.

Abstract

Salt-induced hypertension leads to development of left ventricular hypertrophy in the Dahl salt-sensitive (Dahl/SS) rat. Before progression to left ventricular failure, the heart initially undergoes a compensated hypertrophic response. We hypothesized that changes in myocardial energetics may be an early indicator of transition to failure. Dahl/SS rats and their salt-resistant consomic controls (SS-13(BN)) were placed on either a low- or high-salt diet to generate four cohorts: Dahl-SS rats on a low- (Dahl-LS) or high-salt diet (Dahl-HS), and SS-13(BN) rats on a low- (SSBN-LS) or high-salt diet (SSBN-HS). We isolated left ventricular trabeculae and characterized their mechanoenergetic performance. Our results show, at most, modest effects of salt-induced compensated hypertrophy on myocardial energetics. We found that the Dahl-HS cohort had a higher work-loop heat of activation (estimated from the intercept of the heat vs. relative afterload relationship generated from work-loop contractions) relative to the SSBN-HS cohort and a higher economy of contraction (inverse of the slope of the heat vs. active stress relation) relative to the Dahl-LS cohort. The maximum extent of shortening and maximum shortening velocity of the Dahl/SS groups were higher than those of the SS-13(BN) groups. Despite these differences, no significant effect of salt-induced hypertension was observed for either peak work output or peak mechanical efficiency during compensated hypertrophy.

• Authors: Kenneth Tran, June-Chiew Han, Andrew J Taberner, Carolyn J Barrett, Edmund J Crampin, Denis S Loiselle
• Journal: American journal of physiology. Heart and circulatory physiology (Am J Physiol Heart Circ Physiol) Vol. 311 Issue 3 Pg. H563-71 (09 01 2016) ISSN: 1522-1539 [Electronic] United States
• PMID: 27402668 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 the American Physiological Society.

Chemical References

• Sodium Chloride, Dietary

Topics

• Animals
• Blood Pressure
• Diet, Sodium-Restricted
• Disease Models, Animal
• Energy Metabolism
• Heart Failure (metabolism, physiopathology)
• Hypertension (metabolism, physiopathology)
• Hypertrophy, Left Ventricular (metabolism, physiopathology)
• Myocardial Contraction (physiology)
• Myocardium (metabolism)
• Rats
• Rats, Inbred Dahl
• Sodium Chloride, Dietary
• Ventricular Dysfunction, Left (metabolism, physiopathology)