26 Weight loss in obesity causes a reduction in the creatine kinase rate constant

IntroductionObesity is associated with diminished myocardial energetic stores, as determined by PCr/ATP, and this is restored with weight loss. We have previously demonstrated that the creatine kinase rate constant (k f CK) is elevated in obesity, which may represent a compensatory mechanism preserving ATP delivery. We hypothesised that intentional weight loss would reduce the requirement for increased enzyme activity, and hence k f CK would fall.Methods31 obese individuals (53±13 years, 11 male, BMI 37±5 kg/m-2) underwent comprehensive metabolic phenotyping including MR (3 T, Siemens) for abdominal, hepatic and myocardial fat, and cardiac MR for structure and function. Triple Repetition time Saturation Transfer (TRiST) 31P magnetic resonance spectroscopy was used to measure k f CK. Participants then underwent repeat testing following a dietary weight loss intervention.ResultsMean BMI in the cohort fell from 37±5 kg/m-2 to 33±6 kg/m-2 (p