Lipopolysaccharide- and lipoteichoic acid-mediated pro-inflammatory cytokine production and modulation of tlr2, tlr4 and myd88 expression in human endometrial cells

Toll-like receptor [TLR]-mediated inflammatory processes are supposed to be involved in pathophysiology of spontaneous abortion and preterm labor. Here, we investigated functional responses of human endometrial stromal cells [ESCs] and whole endometrial cells [WECs] to lipopolysaccharide [LPS] and lipoteichoic acid [LTA] Endometrial tissues were obtained from 15 cycling women who underwent laparoscopic tubal ligation. Modulation of TLR2, TLR4 and MyD88 expression and production of pro-inflammatory cytokines by WECs and ESCs in response to LPS and LTA were assessed. WECs and ESCs expressed significant levels of TLR4 and MyD88 transcripts but, unlike WECs, ESCs failed to express TLR2 gene. Regardless of positive results of Western blotting, ESCs did not express TLR4 at their surface as judged by flow cytometry. Immunofluorescent staining revealed intracellular localization of TLR4 with predominant perinuclear pattern. LPS stimulation marginally increased TLR4 gene expression in both cell types, whereas such treatment significantly upregulated MyD88 gene expression after 8 hr [p<0.05]. At the protein level, however, LPS activation significantly increased TLR4 expression by ESCs [p<0.05]. LTA stimulation of WECs was accompanied with non-significant increase of TLR2 and MyD88 transcripts. LPS and LTA stimulation of WECs caused significant production of IL-6 and IL-8 in a dose-dependent manner [p<0.05]. Similarly, ESCs produced significant amounts of IL-6, IL-8 and also TNF-alpha in response to LPS activation [p<0.05]. Our results provided further evidence of initiation of inflammatory processes following endometrial TLR activation by bacterial components which could potentially be harmful to developing fetus

Cytokine profile in the endometrium of normal fertile and women with repeated implantation failure

Repeated Implantation Failure [RIF] is one of the most intricate obstacles in assisted reproduction. The cytokine and chemokine composition of uterine cavity seem to play important roles in the implantation process. To compare the cytokine profile in the endometrium of normal fertile women and those with repeated implantation failure. After enzymatic digestion of endometrial tissues, whole endometrial cells and endometrial stromal cells from RIF and normal fertile women were cultivated and stimulated for cytokine secretion. The levels of IL-10, TGF-beta, IFN-gamma, IL-6, IL-8 and IL-17 in culture supernatants of the two groups were assayed by ELISA and compared together. Endometrial stromal cells and whole endometrial cells of normal fertile women produced higher levels of IL-6, IL-8 and TGF-beta compared to RIF group, although this difference was statistically significant only in endometrial stromal cells [p=0.005, 0.002 and 0.001, respectively]. In addition, endometrial stromal cells of normal fertile women produced lower levels of IL-10 in comparison with RIF group [p<0.005]. Disturbances in cytokine production at the feto-maternal interface could be a cause of implantation failure. A pro-inflammatory cytokine milieu seems to be pivotal for successful implantation