Category Archives: COPD

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Limitations of the Study

The stepwise regression analysis showing that the IL-6/DHEAS ratio was the only significant correlate of MTCSA also illustrates that evaluating the balance between catabolism and anabolism may be more relevant to muscle wasting than looking at individual changes in any catabolic/ anabolic factor. Interestingly, a disruption in the normal balance between catabolism and anabolism also has been associated with the occurrence of cachexia in patients with chronic heart failure.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Muscle Wasting

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Muscle WastingLow Pa02 and systemic use of corticoste-roids can alter the function of the hypothalamic-pituitary axis, but these factors did not seem to play a role in our patients. As mentioned above, the direct effects of proinflammatory cytokines on the testis may lead to decreased testosterone production. Leydig cell atrophy has been reported in COPD patients and also may contribute to low testosterone production.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Anabolic Factors

Increased levels of proinflammatory cytokines reduce testosterone secretion by interfering with Leydig cell function. Furthermore, anabolic hormone deficiency contributes to elevated IL-6 levels since the expression of this cytokine is down-regulated by testosterone and DHEAS. The interactions between cytokines and anabolic steroids in our patients were supported by the negative correlation between IL-6, on the one hand, and Tbio and DHEAS, on the other hand.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Discussion

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Discussion  Univariate analysis indicated that only the IL-6/ DHEAS ratio (r = —0.40; p < 0.01) was significantly correlated with MTCSA. There was no correlation between any of the catabolic and anabolic factors taken individually and MTCSA. No significant correlation was found between BMI and any catabolic and anabolic factors taken individually or any of the catabolic/anabolic factor ratios. In a stepwise multiple regression analysis, the IL-6/ DHEAS ratio explained 20% of the variance in MTCSA (p < 0.005).

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Hypogonadotrophic hypogonadism

Of the 10 hypogon-adic patients, 7 patients had low or normal levels of LH, suggesting an hypogonadotrophic hypogonadism, while the remaining 3 patients had appropriate elevations of LH, suggesting a testicular dysfunction. Patients with an MTCSA of < 70 cm2 had significantly reduced levels of DHEAS compared to control subjects (p < 0.01). The group mean values for LH, cortisol, IGF-1, TNF, TNF-R55, and TNF-R75 were not significantly different among the three groups.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Results

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: ResultsIn that study, an MTCSA of < 70 cm2 was strongly associated with mortality in COPD patients. Analysis of variance and post hoc Tukey comparison tests were used to compare COPD subgroups and control subjects. Simple linear regressions were performed in order to evaluate the possible relationships between catabolic and anabolic factors, and peripheral muscle mass. In COPD, a stepwise multiple regression analysis was performed with MTCSA as the dependent variable and age, FEV1 % predicted, Tbio, DHEAS, IGF-I, cortisol, IL-6, cortisol/DHEAS ratio, IL-6/ Tbio ratio, IL-6/DHEAS ratio, and IL-6/IGF-I ratio as the independent variables. A p value of < 0.05 was considered to be statistically significant.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Statistical Analysis

CT Scan of the Thigh: In order to evaluate MTCSA, a CT scan of the right thigh halfway between the pubic symphisis and the inferior condyle of the femur was performed, as previously described.
Blood Sampling and Analysis: After a resting period of 30 min, antecubital venous blood was sampled between 8:00 am and 9:00 am in overnight fasted subjects. Blood was centrifuged for 15 min, put into aliquots, and stored at — 80°C until further analysis.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Materials and Methods

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Materials and MethodsThe ratio between cortisol and DHEAS was taken as an index of adrenal steroid metabolism, while the ratios of IL-6 and the anabolic factors were used as markers of the catabolic/anabolic balance in these subjects.
Subjects
The study population consisted of 45 men with COPD who were in stable condition, who had participated in our previous study evaluating the impact of low muscle mass on survival in COPD, and in whom blood was available for the quantification of anabolic and catabolic factors.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD: Dehydroepiandrosterone

Reduced levels of dehydroepiandrosterone (DHEA), an adrenal steroid, and a high cortisol/ DHEA ratio are thought to create an imbalance between protein synthesis and degradation favoring catabolism over anabolism in patients with this dis-ease. The potential role of the adrenal hormones in wasting associated with COPD has not been investigated,
At the molecular level, the maintenance of muscle mass is dependent on several intricate and redundant regulating pathways, and it is unlikely that disturbances in one single component of this complex system explain entirely the wasting process.

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPD

Catabolic/Anabolic Balance and Muscle Wasting in Patients With COPDIt is now recognized that peripheral muscle dysfunction adversely affects clinical outcomes in COPD. Concomitantly with muscle structural changes, there is a loss of peripheral muscle mass in patients with this disease, often despite having a normal body mass index (BMI). Peripheral muscle wasting in COPD patients is associated with muscle weakness, decreased exercise capacity, impaired quality of life, and more importantly, decreased survival.

Pages: 1 2 3 4 Next