Cytokines and dietary energy restriction in stable chronic obstructive pulmonary disease patients

Abstract

Tumour necrosis factor (TNF)-a has been found to be increased in malnourished chronic obstructive pulmonary disease (COPD) patients; however, the main cause of this phenomenon remains undetermined. In normal subjects, TNF-a production may be induced by dietary energy deprivation. The aim of this study was to investigate if stable COPD patients present alterations of inflammatory mediators after 48 h of dietary energy restriction.Fourteen COPD patients were admitted to the hospital while receiving an experimental diet with an energy content of approximately one-third of their energy needs. Clinical evaluation, nutritional assessment and serum levels of interleukin (IL)-6, TNF-a and C-reactive protein, and secretion of TNF-a by peripheral blood monocytes were assessed on admission and after the experimental diet. For reference values of the laboratory parameters, blood was collected from 10 healthy, elderly subjects.COPD patients showed significantly higher serum concentrations of IL-6 than control subjects, however, the experimental diet was not associated with statistically significant changes in the inflammatory mediators.The findings of this study, although preliminary because of the limited degree and duration of the energy restriction, suggest that the elevated levels of tumour necrosis factor-a, previously described in undernourished or weight-losing chronic obstructive pulmonary disease patients, may not be linked to a decrease of dietary energy intake. Eur Respir J 2003; 22: 920-925.

Mediators of Chronic Obstructive Pulmonary Disease

“…IL-6 is also increased in the plasma of COPD patients (Debigare et al, 2003;Godoy et al, 2003;Hageman et al, 2003), especially during exacerbations (Wedzicha et al, 2000). Monocytes from COPD patients release more IL-6 in response to stimulation with LPS than cells from normal subjects (Aldonyte et al, 2003).…”

The immune response to resistive breathing

“…Interestingly, in diseases of increased diaphragmatic loading, such as COPD, increased plasma cytokine levels have been documented [47][48][49][50]. Although, initially, these cytokines had been attributed to the bronchial inflammation that accompanies COPD, recent data have shown different regulation of the cytokine response in induced sputum and plasma [47], which suggests that plasma cytokinemia in COPD is not due to an overflow of inflammatory mediators from the local lung compartment.…”

Cytokines and resistive breathing

“…Some of the data prove a significant increase in the blood's proinflammatory cytokine level in COPD accompanied by a significant increase in air way resistance [6][7][8]13]. It has been shown that this increase is not connected to an increase in the blood of cytokine levels caused by their release from inflamma tion foci located in the respiratory system.…”

“…Current experimental and clinical studies show an increase in the cytokine concentration in the blood plasma and respiratory muscles in the illness of the respiratory system accompanied by an increase in the resistance to breathing and also in healthy subjects during breathing with an additional inspiratory resis tive load [6][7][8][9][10][11]. A new concept has been developed based on these data.…”