PROBLEM: Monocyte chemotactic protein-1 (MCP-1), a potent inducer of macrophage recruitment and activation, is overexpressed in the eutopic endometrium of women with endometriosis. Eutopic endometrial cells of women with endometriosis secrete higher levels of MCP-1 than those of normal women, following stimulation with interleukin-1 (IL-1). The aim of this study was to examine whether there is any correlation between the expression of IL-1 receptor type II (IL-1RII), a specific downregulator of IL-1 activity, and that of MCP-1 in the eutopic endometrium of women with endometriosis.
METHOD OF STUDY: Endometrial biopsies of 46 women with endometriosis and 22 healthy women were evaluated simultaneously for IL-1RII and MCP-1 expression by immunohistochemistry.
RESULTS: Our study revealed a highly significant correlation between the decreased expression of IL-1RII and the increased expression of MCP-1 in the endometrial tissue of women with endometriosis (Spearman correlation coefficient r=−0.377, P=0.002), particularly in the initial stages of the disease (stages I and II; r=−0.368, P=0.020 and r=−0.480, P=0.002, respectively). Furthermore, this correlation was observed in the proliferative (r=−0.366, P=0.047) and the secretory phases (r=−0.321, P=0.049) of the menstrual cycle.
CONCLUSIONS: These results suggest that the reduced capability of endometrial tissue to downregulate IL-1 proinflammatory effects may be involved in the increased expression of MCP-1 in the endometrium of women with endometriosis and the establishment of an inflammatory state. The results also indicate a sustained process of cell activation throughout the menstrual cycle.