Leptin and advanced glycation end products receptor (RAGE) in tuberculosis patients

INTRODUCTION: The pathogenesis of consumptive syndrome of tuberculosis (TB) is largely unknown. Leptin concentrations may be high because of the host’s inflammatory response, contributing to weight loss in patients with TB. The receptor for advanced glycation end products (RAGE) is also associated with weight loss in patients with TB and is related to enhanced mortality. The objective of this study was to evaluate the association between leptin and AGE/RAGE. METHODS: Case-control study. Leptin, AGE (carboxymethyl lysine, CML) and soluble RAGE (sRAGE) were measured from blood samples by ELISA. RESULTS: We included in the study 34 patients with TB and 34 controls. We found an inverse correlation between serum leptin levels and sRAGE, only in cases (r = -0.609, p < 0.0001). sRAGE levels were lower in patients with TB who died as compared with patients who survive (21.90 ± 4.24 pg/mL vs 66.14 ± 29.49 pg/mL; p = 0.045). Leptin levels were higher in patients with TB who died as compared with patients who survive (14.11 [7.48–14.11] ng/mL vs 3.08 [0.54–6.34] ng/mL; p = 0.028). CONCLUSIONS: We identified lower sRAGE levels and higher leptin levels in patients with TB who died as compared with patients who survive. In addition, an inverse and significant correlation between serum leptin and sRAGE levels was demonstrated. Future studies, with a larger sample size and in different settings, including not only hospitalized patients, are needed to confirm these findings.