Tumour necrosis factor alpha and oxidative stress as maintaining factors in the evolution of anorexia nervosa

OBJECTIVE: Aim of the study was to evaluate tumour necrosis factor α (TNF-α) axis and oxidative status in patients with anorexia nervosa (AN) seeking a possible correlation with both nutritional status and evolution of the disease. SUBJECTS AND METHODS: Thirty-nine consecutive women with AN and an age-matched healthy control group were studied. Patients were 26±9 yr, with a body mass index (BMI) of 13.9±2 kg/m2. TNF-α, its receptors TNF-R55 and TNF-R75, and oxidative status markers (selenium, ascorbic/dehydroascorbic acid, retinol, α-tocopherol, selenium-dependent gluthatione peroxidase, reduced/oxidated gluthatione) were measured. A correlation with both nutritional indexes (body weight, BMI, albumin, prealbumin, transferrin, lymphocyte count) and disease duration was investigated. Pearson’s correlation and unpaired Student’s t-test were used to compare patients and controls. RESULTS: TNF-α and oxidative status markers were significantly higher in patients than controls and TNF-α was directly related to dehydroascorbic acid (p<0.05). Both TNF-R55 and TNF-R75 were higher in patients with duration of disease longer than one year as compared to controls and patients with shorter duration. Receptors inversely correlated with BMI (p<0.05 and p<0.01) and directly with disease duration (p<0.05). Inverse correlation between disease duration and BMI was present (p<0.01). CONCLUSIONS: The study showed activation of TNF-α axis and oxidative stress in AN patients, as well as correlation between the two systems. Due to the correlation between TNF receptors and both BMI and disease duration, a possible role of pro-inflammatory cytokines in the evolution of the eating disorder is suggested.