CONTEXT: Anorexia nervosa (AN) is an eating disorder, resulting in sustained low weight and marked decrease in fat mass. Interleukin 6 (IL-6) may play a role in appetite, energy expenditure and body weight control. IL-6 acts through binding with membrane receptor (IL-6R) and activates glycoprotein 130 (gp130) signalling. Both IL-6R and gp130 are present in the blood in the soluble forms (sIL-6R and sgp130 respectively). sIL-6R sensitizes cells towards IL-6, whereas sgp130 inhibits gp130 signalling. OBJECTIVE: To estimate circulating IL-6/sIL-6R/sgp130 system and its relationships with body weight and resting energy expenditure (REE) in AN women. PATIENTS: We examined 19 women with AN and 27 healthy normal-weight female controls. MEASUREMENTS: Indirect calorimetry and the measurement of serum IL-6, sIL-6R and sgp130 concentrations were performed in all the subjects. RESULTS: REE was decreased in AN women (P < 0·001). Serum IL-6 was higher in AN women in comparison with control group (P = 0·005). Serum sIL-6R was lower (P = 0·009) and serum sgp130 was higher (P = 0·004) in AN women in comparison with controls. IL-6 and sIL-6R were related to REE in the entire study population (r = -0·54, P < 0·001 and r = 0·48, P = 0·001 respectively) and in AN group (r = -0·54, P = 0·024 and r = 0·60, P = 0·011 respectively). CONCLUSIONS: Increased IL-6 in AN seems to be compensated by the changes in sIL-6R and sgp130, which are directed towards inhibition of IL-6 action. The balance between these factors might play a role in the regulation of energy expenditure in AN.
CONTEXT: Anorexia nervosa (AN) is an eating disorder, resulting in sustained low weight and marked decrease in fat mass. Interleukin 6 (IL-6) may play a role in appetite, energy expenditure and body weight control. IL-6 acts through binding with membrane receptor (IL-6R) and activates glycoprotein 130 (gp130) signalling. Both IL-6R and gp130 are present in the blood in the soluble forms (sIL-6R and sgp130 respectively). sIL-6R sensitizes cells towards IL-6, whereas sgp130 inhibits gp130 signalling. OBJECTIVE: To estimate circulating IL-6/sIL-6R/sgp130 system and its relationships with body weight and resting energy expenditure (REE) in AN women. PATIENTS: We examined 19 women with AN and 27 healthy normal-weight female controls. MEASUREMENTS: Indirect calorimetry and the measurement of serum IL-6, sIL-6R and sgp130 concentrations were performed in all the subjects. RESULTS: REE was decreased in AN women (P < 0·001). Serum IL-6 was higher in AN women in comparison with control group (P = 0·005). Serum sIL-6R was lower (P = 0·009) and serum sgp130 was higher (P = 0·004) in AN women in comparison with controls. IL-6 and sIL-6R were related to REE in the entire study population (r = -0·54, P < 0·001 and r = 0·48, P = 0·001 respectively) and in AN group (r = -0·54, P = 0·024 and r = 0·60, P = 0·011 respectively). CONCLUSIONS: Increased IL-6 in AN seems to be compensated by the changes in sIL-6R and sgp130, which are directed towards inhibition of IL-6 action. The balance between these factors might play a role in the regulation of energy expenditure in AN.