Leptin and energy metabolism in pulmonary tuberculosis

Abstract

Background: Pulmonary tuberculosis is the classic cause of "consumption," but the pathogenesis of such wasting is largely unknown. Animal studies in other conditions suggest that leptin may be a mediator between proinflammatory cytokine activity and wasting. Objective: We tested whether the leptin concentration, after control for body fat mass, is higher during active pulmonary tuberculosis than after recovery and whether it correlates with energy metabolism and proinflammatory cytokine activity. Design: Nondiabetic adults with pulmonary tuberculosis (n = 32) were recruited into a prospective observational study. Patients found to be antibody positive for human immunodeficiency virus were excluded from the study. Dual-energy X-ray absorptiometry, indirect calorimetry, and food intake protocols were performed at baseline and after 1 and 6 mo of tuberculosis treatment. Fasting plasma leptin, tumor necrosis factor ␣ and its soluble receptor, and interleukin 6 were measured by enzyme-linked immunosorbent assay. Results: Resting energy expenditure was close to Harris-Benedict predictions and did not change significantly during treatment, but energy intake increased. Leptin concentration was correlated in a log-linear fashion with percentage body fat but was independent of cytokines and energy intake. There was no significant difference in leptin, corrected for energy balance and fat mass, at baseline and after 1 and 6 mo of treatment. Conclusions: These data are compatible with recovery from anorexia or starvation without discernible hyper-or hypometabolism. The close correlation of leptin with body fat mass is similar to observations in healthy subjects. No additional influence of disease state or proinflammatory cytokine activity was found. Leptin does not appear to be a component of the immune response to human pulmonary tuberculosis, and thus it cannot account for the weight loss and anorexia associated with tuberculosis.Am J Clin Nutr 2003;77:392-8.

A Clinical Correlate of the Dysregulated Immunoendocrine Response in Human Tuberculosis

“…While some reports showed increased leptin levels in TB patients [6] , they were found decreased in another study in which they were also associated with body fat and loss of appetite [7] . Schwenk et al [8] suggest that leptin is not involved in the loss of weight and appetite in TB, although in their study leptin correlated with body mass. Since a tissue granulomatous reaction is observed in tuberculosis together with weight loss, and leptin is involved in both metabolism and the immune response, it is difficult to discern to what extent leptin levels are related to an energy imbalance or to the chronic immune process underlying the infection.…”

Leptin Levels in Various Manifestations of Pulmonary Tuberculosis

“…On the other hand, Van Crevel et al [24] have shown that both plasma leptin and ex vivo IFN-gamma production were low and increased upon successful antituberculous treatment. Schwenk et al [31] did not find any correlation between serum IL-6, TNF- α , and leptin levels.…”

Effect of tuberculosis treatment on leptin levels, weight gain, and percentage body fat in Indonesian children

“…Leptin is a 16-kDa protein coded by obese genes, especially in adipocytes10). Leptin levels are correlated with body mass index, increasing in overweight cases and decreasing in wasting cases51112). Leptin regulates appetite and energy consumption at a hypothalamic level by binding with its specific receptor9).…”