Catabolic/anabolic balance and muscle wasting in patients with COPD.
BACKGROUND
The mechanisms leading to muscle wasting in patients with COPD are still uncertain. This study was undertaken to evaluate the relationships among circulating levels of catabolic factors (ie, interleukin [IL]-6 and cortisol), anabolic factors (ie, bioavailable testosterone [Tbio], dehydroepiandrosterone sulfate [DHEAS], and insulin-like growth factor [IGF]-I), and mid-thigh muscle cross-sectional area (MTCSA) in patients with COPD.


METHODS
Serum levels of the above factors were measured in 45 men with COPD (mean [+/- SEM] FEV(1), 43 +/- 3% predicted; mean age, 67 +/- 1 years) and 16 sedentary healthy men of similar age. MTCSA was quantified using CT scanning. Patients with COPD were subdivided into two groups according to the MTCSA (< 70 or >or= 70 cm(2)).


RESULTS
There was a greater prevalence of hypogonadism (ie, Tbio, < 2 nmol/L) in patients with COPD compared to control subjects (22% vs 0%, respectively). Patients with an MTCSA of < 70 cm(2) had significantly reduced levels of DHEAS compared to those in healthy subjects (p < 0.01). IL-6 levels were significantly higher in both subgroups of COPD patients compared to those in control subjects (p < 0.005). The cortisol/DHEAS, IL-6/DHEAS, IL-6/Tbio, and IL-6/IGF-I ratios were significantly greater in COPD patients with an MTCSA of < 70 cm(2) compared to those in control subjects (p < 0.05). The cortisol/DHEAS and IL-6/DHEAS ratios were also significantly greater in COPD patients with an MTCSA of < 70 cm(2) than in COPD patients with an MTCSA of >or= 70 cm(2) (p < 0.05). In a stepwise multiple regression analysis, the IL-6/DHEAS ratio explained 20% of the variance in MTCSA (p < 0.005).


CONCLUSIONS
Catabolic/anabolic disturbances were found in COPD patients leading to a shift toward catabolism and possibly to the development of peripheral muscle wasting.
Debigaré
Richard
R
Centre de Recherche, Hôpital Laval, Institut Universitaire de Cardiologie et de Pneumologie, Université Laval, Sainte-Foy, QC, Canada.
Marquis
Karine
K
Côté
Claude H
CH
Tremblay
Roland R
RR
Michaud
Annie
A
LeBlanc
Pierre
P
Maltais
François
F
D000368:Aged; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism; D009135:Muscular Diseases / Q000150:complications / Q000378:metabolism*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000378:metabolism*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D013739:Testosterone / Q000378:metabolism; D013848:Thigh; D014057:Tomography, X-Ray Computed
D015850:Interleukin-6; D013739:Testosterone; D019314:Dehydroepiandrosterone Sulfate; D007334:Insulin-Like Growth Factor I; D006854:Hydrocortisone