Myocardial Energetics in Obesity: Enhanced ATP Delivery Through Creatine Kinase With Blunted Stress Response
Authors' conclusion
In the obese resting heart, the myocardial CK reaction rate is increased, maintaining ATP delivery despite reduced phosphocreatine/ATP. During increased workload, although the nonobese heart increases ATP delivery through CK, the obese heart does not; this is associated with reduced systolic augmentation and exercise tolerance. Weight loss reverses these energetic changes.
Study context
- Population
- Obese and non-obese volunteers without coexisting CVD
- Participants
- 80 participants
- Comparison
- Obese vs non-obese controls; obese before vs after dietary weight loss
- Obesen = 45
- Controlsn = 35reference
- Outcome
- Myocardial ATP transfer rate through creatine kinase (CK) (kfCK), phosphocreatine/ATP and ATP delivery by 31P MR spectroscopy, at rest and during dobutamine stress
Main finding
As reported in the abstract
Resting myocardial energetics · rest
| Group | Phosphocreatine/ATP | kfCKrest | ATP delivery |
|---|---|---|---|
| Obese | 1.9±0.3 | 0.23±0.07 s-1 | 2.5±0.9 µmol·g-1·s-1 |
| Controls | 2.2±0.2 | 0.16±0.08 s-1 | 2.2±1.1 µmol·g-1·s-1 |
Phosphocreatine/ATP
Obese1.9±0.3
Controls2.2±0.2
kfCKrest
Obese0.23±0.07 s-1
Controls0.16±0.08 s-1
ATP delivery
Obese2.5±0.9 µmol·g-1·s-1
Controls2.2±1.1 µmol·g-1·s-1
- Obese vs Controls: P < 0.001 — phosphocreatine/ATP 14% lower
- Obese vs Controls: P = 0.002 — kfCKrest 33% higher
- Obese vs Controls: P = 0.232 — resting ATP delivery
Further findings
%
| Outcome | Obese | Controls | P value |
|---|---|---|---|
| Absolute increase in LVEF with stress · dobutamine stress | +16 (SD 7) | +21 (SD 4) | P = 0.031 |
Response to dobutamine stress (kfCK, ATP delivery)
- Controls: increase in kfCK +86%
- P < 0.001
- Controls: increase in ATP delivery +80%
- P < 0.001
- Obese: no significant increase in kfCK
- P = 0.117
- Obese: no significant increase in ATP delivery
- P = 0.608
Energetics after weight loss (obese) · after dietary weight loss
- Weight loss −11±5% body weight improved energetic changes; no significant difference vs controls
Original publication
Myocardial Energetics in Obesity: Enhanced ATP Delivery Through Creatine Kinase With Blunted Stress Response. Circulation. Published 6 March 2020. doi:10.
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