PT  - JOURNAL ARTICLE
AU  - Darren T. Hwee
AU  - Adam R. Kennedy
AU  - James J. Hartman
AU  - Julie Ryans
AU  - Nickie Durham
AU  - Fady I. Malik
AU  - Jeffrey R. Jasper
TI  - The Small-Molecule Fast Skeletal Troponin Activator, CK-2127107, Improves Exercise Tolerance in a Rat Model of Heart Failure
AID  - 10.1124/jpet.114.222224
DP  - 2015 Apr 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 159--168
VI  - 353
IP  - 1
4099  - http://jpet.aspetjournals.org/content/353/1/159.short
4100  - http://jpet.aspetjournals.org/content/353/1/159.full
SO  - J Pharmacol Exp Ther2015 Apr 01; 353
AB  - Heart failure–mediated skeletal myopathy, which is characterized by muscle atrophy and muscle metabolism dysfunction, often manifests as dyspnea and limb muscle fatigue. We have previously demonstrated that increasing Ca2+ sensitivity of the sarcomere by a small-molecule fast skeletal troponin activator improves skeletal muscle force and exercise performance in healthy rats and models of neuromuscular disease. The objective of this study was to investigate the effect of a novel fast skeletal troponin activator, CK-2127107 (2-aminoalkyl-5-N-heteroarylpyrimidine), on skeletal muscle function and exercise performance in rats exhibiting heart failure–mediated skeletal myopathy. Rats underwent a left anterior descending coronary artery ligation, resulting in myocardial infarction and a progressive decline in cardiac function [left anterior descending coronary artery heart failure (LAD-HF)]. Compared with sham-operated control rats, LAD-HF rat hindlimb and diaphragm muscles exhibited significant muscle atrophy. Fatigability was increased during repeated in situ isokinetic plantar flexor muscle contractions. CK-2127107 produced a leftward shift in the force-Ca2+ relationship of skinned, single diaphragm, and extensor digitorum longus fibers. Exercise performance, which was assessed by rotarod running, was lower in vehicle-treated LAD-HF rats than in sham controls (116 ± 22 versus 193 ± 31 seconds, respectively; mean ± S.E.M.; P = 0.04). In the LAD-HF rats, a single oral dose of CK-2127107 (10 mg/kg p.o.) increased running time compared with vehicle treatment (283 ± 47 versus 116 ± 22 seconds; P = 0.0004). In summary, CK-2127107 substantially increases exercise performance in this heart failure model, suggesting that modulation of skeletal muscle function by a fast skeletal troponin activator may be a useful therapeutic in heart failure–associated exercise intolerance.