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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. [ABSTRACT FROM AUTHOR]

Background: Muscle weakness is a part of the wasting syndrome associated with TB. Cytokines are candidates as the initial causative agents of the metabolic changes in TB. The objective of this study is to assess the peripheral and respiratory muscle strength in patients with TB and controls and relate these findings with leptin, IL‐6 and TNF‐α serum levels. Methods: Case–control study. Hospitalized patients with pulmonary TB and controls were included. Maximal voluntary handgrip strength (HS), maximal inspiratory pressure (MIP) and maximum expiratory pressure (MEP) were measured. Leptin, IL‐6 and TNF‐α dosage were performed. Results: We included 35 cases and 35 controls. Leptin was lower and TNF‐α levels were higher in TB patients than in controls (P < .0001 for both). Body mass index (BMI), HS, MIP and MEP were all significantly lower in cases than in controls (P < .0001). Lower leptin and higher TNF‐α levels are associated with malnutrition and reduced MIP, MEP and HS. Patients who reported fever and those with positive culture for Mycobacterium tuberculosis had higher serum levels of IL‐6. Conclusion: Peripheral and respiratory muscle strength and leptin levels were reduced in patients with active TB. Lower levels of leptin and higher levels of TNF‐α were associated with malnutrition and with reduced MIP, MEP and HS. [ABSTRACT FROM AUTHOR]

Introduction: The receptor for advanced glycation end products (RAGE) is expressed in normal lungs and is upregulated during infection. AGEs and RAGE cause oxidative stress and apoptosis in lung cells. The objective of this study is to evaluate levels of AGEs and its soluble receptor (sRAGE), and to investigate their relationship with food intake and nutritional status, in a university-affiliated hospital in Brazil. Methods: Case-control study, from June 2017 to June 2018. AGE (carboxymethyl lysine, CML) and sRAGE were measured from blood samples by Elisa. Nutritional assessment was performed by body mass index, triceps skin-fold thickness, mid-arm circumference, mid-arm muscle circumference, bioelectrical impedance analysis, and food frequency questionnaire. Results: We included in the study 35 tuberculosis (TB) patients and 35 controls. The mean sRAGE levels were higher in TB patients than in controls (68.5 ± 28.1 vs 57.5 ± 24.0 pg/mL; p = 0.046). Among cases that were current smokers, lower sRAGE levels were associated with mortality, evaluated at the end of hospitalization (p = 0.006), and with weight loss (p = 0.034). There was no statistically significant difference in CML levels and diet CML content between cases and controls. Malnutrition was more frequent in cases, but there was no correlation between nutritional parameters and CML or sRAGE levels. Conclusions: TB patients had higher sRAGE levels than controls, although it is not clear that this difference is clinically relevant. Also, sRAGE was associated with weight loss and mortality. [ABSTRACT FROM AUTHOR]