Abstract
Aim: Increases in resting energy expenditure (REE) have been previously shown in wasting COPD patients. Decreased leptin levels have been associated with weight loss in patients with emphysema, however, adipose tissue (AT) leptin expression has not been studied previously in COPD. Our scope was to investigate the REE, leptin AT expression and serum levels in patients with COPD and different BMI.
Methods: 44 patients with stable COPD were divided into 3 groups: Group 1 with BMI ≤20kg/m2 (n=9, 9 males, 61.4±8.2 years, FEV1 33.8±19.8%), Group 2 with BMI 20-30kg/m2 (n=24, 20 males, 62.8±5.9 years, FEV1 59.4±22.7%) and Group 3 with BMI >30kg/m2 (n=11, 9 males, 60.2±8.0 years, FEV1 60.5±19.0%). REE was measured by indirect calorimetry using a ventilated hood system. Samples of subcutaneous AT were obtained by percutaneous biopsy. AT gene expression was measured in duplicates with aid of the real-time PCR using the TaqMan gene expression assays.
Results: REE per kg of body weight (REE/kg) decreased from Group 1 to Group 2 and 3 (32.9±6.1 vs 26.2±5.8 vs 23.9±6.6 kcal/kg/24 h, p=0.006), whereas leptin AT expression (ΔΔCt) and serum leptin levels increased (8.8±9.4 vs 44.1±20.9 vs 58.1±15.8, p<0.001; 0.8±0.9 vs 11.9±16.5 vs 28.9±21.5 μg/ml, p<0.001; respectively). There was a significant inverse relationship between REE/kg and both AT leptin expression and serum leptin levels (R= -0.458, p=0.002; R= -0.522, p<0.001, respectively).
Conclusion: In patients with stable COPD resting metabolic rate increased with decreasing BMI, in association with reductions in AT leptin expression. Low leptin AT production is associated with hypermetabolism in lean COPD patients.
Support: VEGA 1/0227/11 and VVGS 36/10-11.
- © 2011 ERS