Plasma leptin; tumor necrosis factor- alpha and nutritional status in chronic obstructive pulmonary disease patients

ABSTRACT

Chronic obstructive pulmonary disease [COPD] is a syndrome of chronic wasting associated with a chronic inflammatory response. Leptin is a protein mainly secreted by adipocytes and it has a major role in control of body weight and energy expenditure. It has been suggested that increased levels of circulating leptin may contribute to anorexia in pathologic conditions including COPD. This study aimed to investigate, prospectively, the potential role of circulating plasma leptin and tumor necrosis factor- alpha [TNF- alpha] levels in the malnutrition of COPD patients. Sixty COPD patients and ten healthy control subjects participated in this study. Sixty COPD patients were divided into 3 groups Group I acute patients without malnutrition [n=20]; Group II stable patients without malnutrition [n=20]; and Group III stable patients with malnutrition [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- alpha levels, serum transferring [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- alpha levels was measured by ELISA. The difference between group and correlation of these parameters were analyzed. Nutritional parameters were significantly lower in Group III than other groups [P<0.05]. Serum leptin levels were significantly lower in Group III [COPD, with malnutrition, stable disease] compared to either Group II [COPD, without malnutrition, stable disease] or controls [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 TNF- alpha levels between Group I, Group II, Group III and controls [P >0.05]. There was no significant correlation between leptin and TNF- alpha in any group. 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- alpha and leptin during the regulation of the energy balance in COPD patients. In addition, circulating leptin works independently of the TNF- alpha system and does not primarily affect BMI in COPD patients