Introduction:Chronic obstructive pulmonary disease(COPD) is a syndrome of chronic wasting,in part associated with a chronic inflammatory response. Leptin is a protein mainly secreted by adipocytes, and the major function of leptin is its role in control of body weight and energy expenditure.It is suggested that increased levels of circulating leptin may contribute to anorexia in pathologic conditions including COPD. Several studies have provided evidence for a link between leptin and proinflammatory cytokines such as tumor necrosis factor- α (TNF- α).
Aim of work: This study aimed to investigate, prospectively, the potential role of circulating plasma leptin and TNF- α levels in the malnutrition of COPD patients, and to observe the changes of serum leptin levels during acute exacerbations. Also to investigate the relationship between leptin and TNF- α in COPD patients;and to determine whether plasma leptin levels are related to body mass index or to TNF- α levels .
Patients & Methods : Sixty COPD patients and ten healthy control subjects participated in this study. Sixty COPD patients were divided into 3 groups:Group I: Patients without malnutrition, during acute exacerbation( n=20); Group II: Patients without malnutrition, during stable disease( n=20); and Group III: Patients with malnutrition during stable disease(n=20). To eliminate the effect of sex differences, all patients and controls were males. Body mass index (BMI), triceps skin-fold thickness (TSF), mid-upper arm circumference (MAC), mid-upper arm muscle circumference (MAMC), serum leptin and TNF- α levels, serum transferrin (TF), serum albumin (Alb),serum prealbumin, total lymphocytes count (TLC), forced expiratory volume in one second (FEV1), maximal inspiration pressure (MIP) and maximal expiration pressure (MEP) were measured in all participants. Leptin levels were measured by ELISA; TNF- α levels were measured by ELISA. The between group difference and correlation of these parameters were analyzed.
Results:Nutritional parameters were significantly lower in Group 111 than other groups(P0.05). There was no significant correlation between leptin and TNF- α in any group.
Conclusions: Leptin was not involved in anorexia and weight loss of COPD patients. There was no statistically significant difference in serum leptin levels between COPD patients during stable stage and acute exacerbation, and there was no significant correlation between TNF- α and leptin during the regulation of the energy balance in COPD patients.In addition,circulating leptin works independently of the TNF- α system and does not primarily affect BMI in COPD patients.