S100B in underweight and weight-recovered patients with anorexia nervosa.

Anorexia nervosa (AN) commonly arises during adolescence, leading to interruptions of somatic and psychological development as well as to cortical atrophy and reductions of brain volume. While most brain changes shift towards normal with weight restoration, it is not certain whether they are related to the loss of brain cells, neuropil or merely due to fluid shifts. We measured S100B serum concentrations and psychometric characteristics in 34 patients with acute AN, 19 weight-recovered patients and 35 healthy control women (HCW). Plasma tryptophan and leptin levels were determined as markers for malnutrition and neuroendocrine adaptation to semi-starvation. Peripheral S100B concentrations of acute and former AN patients were not elevated and not statistically different from HCW. BMI, peripheral leptin levels and measures of psychopathology as well as executive cognitive functioning did not correlate with S100B. Plasma tryptophan was positively related to S100B. Our results are in line with our previous findings showing unaltered GFAP and NSE plasma levels in patients with acute AN. Together they do not support hypotheses comprising the degeneration of glial or neuronal cells to explain common signs of brain atrophy in patients with acute AN.