Circulating interleukin 6 and soluble forms of interleukin 6 receptor and glycoprotein 130 in women with anorexia nervosa
M. Karczewska-Kupczewska1, I. Kowalska1, A. Nikolajuk1,2, A. Adamska1, E. Otziomek1, M. Gorska1 & M. Straczkowski1,2
Introduction: 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 in central nervous system. IL-6 acts through binding with membrane receptor (IL-6R) and activates glycoprotein 130 (gp130) signaling. 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 signaling. The aim of the present study was to estimate circulating IL-6/sIL-6R/sgp130 system and its relationships with body weight and resting energy expenditure (REE) in AN women.
Methods: We examined 19 women with AN and 27 healthy normal weight female controls. Euglycemic hyperinsulinemic clamp, indirect calorimetry and the measurement of serum IL-6, sIL-6R and sgp130 concentrations were performed in all the subjects.
Results: We did not observe differences in insulin sensitivity between AN and control subjects. REE was decreased in AN women (P<0.001). Serum IL-6 was higher in AN women in comparison with control group (P=0.04). Serum sIL-6R was lower (P=0.009) and serum sgp130 was higher (P=0.004) in AN women in comparison with controls. In the entire study population, BMI and REE were inversely related to IL-6 (r=-0.45, P=0.02 and r=-0.62, P<0.001, respectively) and positively to sIL-6R (r=0.36, P=0.015 and r=0.42, P=0.013, respectively). Correlation between IL-6 and REE was also present in AN group (r=-0.55, P=0.013).
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.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported however funding details unavailable.