PLASMA LEPTIN, TUMOR NECROSIS FACTOR ALPHA, AND NUTRITIONAL STATUS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS

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 factorα (TNFα). Aim of work: This study aimed to investigate, prospectively, the potential role of circulating plasma leptin and TNFα 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 TNFα in COPD patients;and to determine whether plasma leptin levels are related to body mass index or to TNFα 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 TNFα 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; TNFα 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(P<0.05). Serum leptin levels were significantly lower in Group III (COPD, with malnutrition, stable disease) [(5.7±2.7) ng/ml] than in Group II (COPD, without malnutrition, stable disease) [(9.7±5.3) ng/ml] and controls [(12.2±2.5) ng/ml] (P <0.05). However, the difference between Group I (COPD, without malnutrition, acute state), Group II (COPD, without malnutrition, stable disease), and controls was not statistically significant (P >0.05). There was no statistically significant difference in serum TNFα levels between Group I, Group II, Group III and controls (P >0.05). There was no significant correlation between leptin and TNFα 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 TNFα and leptin during the regulation of the energy balance in COPD patients.In addition,circulating leptin works independently of the TNFα system and does not primarily affect BMI in COPD patients.