Dysfunction of inflammatory pathways in adolescent female patients with anorexia nervosa

The pathogenesis of Eating Disorders is still unknown. However, a growing body of evidence shows that there are changes in cytokine levels and an alteration in the stress response in patients with anorexia nervosa (AN). For this reason, we decided to test whether there are differences in immune parameters involved in the regulation of the inflammatory response between female adolescents with AN and healthy adolescents.

The sample 27 drug-naïve AN patients the study sample included 27 AN patients at a very early stage of the disease and 23 healthy controls. Plasma and peripheral blood mononuclear cells (PBMCs) were obtained for biochemical study.

Plasma levels of the pro-inflammatory cytokines TNF-α and IL-1β were significantly increased in patients with AN, while the levels of prostaglandins PGE₂ (proinflammatory) and 15d-PGJ₂, (anti-inflammatory) were lower compared with controls. Protein expression in PBMCs of cyclooxygenase-2 (COX-2) and the activated forms of the mitogen-activated protein kinases p38 and ERK were also increased in the AN group. Expression levels of the anti-inflammatory factor peroxisome proliferator-activated receptor gamma (PPARγ) were significantly decreased in patients. Plasma levels of lipid peroxidation markers -TBARS- were not increased in patients with AN. Components of the biochemical inflammatory response (COX-2, PGE₂, TBARS, 15d-PGJ₂, ERK, p65 NFκB) and glucocorticoid receptor -GR- expression and the scores on the impulsivity measures in the BARRATT, EDI and BITE questionnaires showed a significant correlation within the AN patients group.

The results for female adolescent patients with AN indicate that there is a dysfunction of intra- and intercellular inflammatory pathways characterized by higher levels of pro-inflammatory parameters in plasma and a decrease in one of the controlling cytoplasmic-nuclear pathways implicated in their modulation (i.e. PPARγ) with, at this very early stage of the disease, no effect on oxidative stress markers plasma levels. Most notably, higher severity of illness (restrictive and purging behaviour) correlated with higher levels of inflammatory markers.