Reduced expression of interleukin-11 and interleukin-6 in the periimplantation endometrium of excessive ovarian responders during in vitro fertilization treatment.
BACKGROUND
Impaired implantation in assisted reproduction cycles with high serum estradiol (E2) concentrations may be related to abnormal endometrial functions.


OBJECTIVE
The in vivo expression of T helper type 2 (Th2) cytokines in the periimplantation endometrium of infertile patients was compared between natural and stimulated cycles.


METHODS
Uterine flushings and endometrial biopsies were collected 7 d after the LH surge in natural cycles or after human chorionic gonadotropin injection in stimulated cycles. Th2 cytokines were determined by immunolocalization and by ELISA. Natural cycles were in group A, whereas stimulated cycles with peak serum E2 of no more than 20,000 pmol/liter (moderate responders) and more than 20,000 pmol/liter (excessive responders) were classified as group B and group C, respectively.


RESULTS
Higher E2 had a negative effect on IL-11 and IL-6 expression in the endometrium and IL-11 concentration in the uterine flushing. In endometrial biopsies, a significantly lower immunostaining of stromal IL-11 (P < 0.001) and glandular IL-6 (P < 0.05) was detected in group C compared with that of groups A and B. IL-11 concentration by ELISA was significantly lower in group C (P < 0.05). Endometrial leukemia inhibitory factor and IL-4 expression was similar in the three groups. In uterine flushings, a significantly higher percentage of women in group C had undetectable IL-11 and a lower IL-11 concentration (P < 0.01) compared with group A, whereas no difference in IL-6 concentration was noted in the three groups.


CONCLUSIONS
Reduced expression of IL-11 and IL-6 in periimplantation endometrium may account for lower implantation in excessive responders.
Makkar
Guneet
G
Department of Obstetrics and Gynaecology, The University of Hong Kong, 6/F Professorial Block, Queen Mary Hospital, Pokfulam Road, Hong Kong.
Ng
Ernest H Y
EH
Yeung
William S B
WS
Ho
P C
PC
D000328:Adult; D001706:Biopsy; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D010064:Embryo Implantation; D004717:Endometrium / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000628:therapy; D017370:Interleukin-11 / Q000032:analysis*; D015847:Interleukin-4 / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis*; D053605:Leukemia Inhibitory Factor; D010053:Ovary / Q000187:drug effects; D018418:Th2 Cells / Q000378:metabolism
D006063:Chorionic Gonadotropin; D017370:Interleukin-11; D015850:Interleukin-6; C507837:LIF protein, human; D053605:Leukemia Inhibitory Factor; D015847:Interleukin-4; D004958:Estradiol