Immune interferon gamma inhibits translational mobility of a plasma membrane protein in preimplantation stage mouse embryos: a T-helper 1 mechanism for immunologic reproductive failure

Effects of toosendanin on pregnancy and uterine immunity alterations in mice

This study was conducted to explore the abortifacient effect and the mechanisms of the Chinese herbal medicine component toosendanin, and to elucidate the significance of the Th1 cytokines IFN-gamma and TNF-alpha, CD4+ and CD8+ T lymphocytes in the occurrence of abortion. Graded doses of toosendanin were given by intraperitoneal injection (i.p.) to mice at day 5, 6, 7 of gestation. The levels of Th1 cytokines (IFN-gamma, TNF-alpha) in serum and uterine tissues from mice sacrificed at day 8 were analyzed by enzyme linked immunosorbent assay (ELISA). Presence of T lymphocytes in endometrium was detected by immunohistochemistry. The results revealed that injection of toosendanin could produce a dose-dependent toxicity. The IFN-gamma, TNF-alpha content in serum and uterine tissues were increased significantly. The CD4+ and CD8+ T lymphocytes were also increased in the endometrium of toosendanin treated groups. In conclusion, toosendanin is pregnancy-toxic to animals and it is relevant to the increased contents of IFN-gamma, TNF-alpha and CD4+, CD8+ T lymphocytes.

Effect of Kidney-replenishing herb on the indoleamine 2,3-dioxygenase of human syncytiotrophoblasts cultured in vitro and the balance of helper T-cell cytokines

BACKGROUND

There is complicated pathogeny involved in spontaneous abortion. At present, the focus of study is on the interface between mother and fetus, the trophoblasts. Indoleamine 2,3-dioxygenase (IDO) is the first and regulatory enzyme in the major route of l-tryptophan catabolism, which induces immunosuppression of T lymphocytes. In the present study we investigated the effect of Kidney-replenishing herb on the expression and activity of IDO in human syncytiotrophoblasts cultured in vitro and the balance of helper T cell (Th) cytokines.

METHODS

Syncytiotrophoblasts were cultured in vitro for 24, 48 or 72 h, with either control serum or serum made from Kidney-replenishing herb, without or with different concentrations of the IDO inhibitor 1-methyltryptophan (1-MT). Reverse transcription-polymerase chain reaction was applied to analyze the IDO mRNA transcription of syncytiotrophoblasts and Western blotting was applied to determine the expression of IDO protein in syncytiotrophoblasts. The concentration of interleukin-10 and interferon-gamma in co-culture medium of syncytiotrophoblasts and decidual T lymphocytes was determined by enzyme-linked immunosorbent assay. High-performance liquid chromatography was used to determine the concentration of kynurenine (Kyn) and tryptophan (Tyr) in the co-culture medium, and the ratio of Kyn/Try was used to assess IDO activity.

RESULTS

IDO mRNA and protein were detected in human syncytiotrophoblasts cultured in vitro. The IDO inhibitor 1-MT caused the balance of Th cytokines to depart from type 2; when IDO activity was inhibited, Kidney-replenishing herb improved the expression of IDO mRNA and protein, promoted IDO activity and caused the balance of Th cytokines depart from type 1.

CONCLUSION

Kidney-replenishing herb improves the expression of IDO mRNA and protein, promotes IDO activity to an appropriate value, resumes the balance of Th cytokines and regulates maternofetal tolerance.

Maternal tolerance to H-Y is independent of IL-10

It has been suggested that the maternal immune system favors noncytotoxic, "TH-2" immune responses in order to tolerate the developing fetus. In some strains of mice, pregnant females will reject a male skin graft, even as they tolerate their male fetuses. This rejection is based on responsiveness to the male antigen H-Y. In this study we test whether functional maternal tolerance of male fetuses is critically dependent on the TH-2 cytokine Interleukin 10 (IL-10). Normal and IL-10-deficient (10-KO) females were sensitized against H-Y by intraperitoneal injection of male spleen cells before mating with 10-KO males. Litters born to 10-KO females were of comparable size to those born to normal females of the same genetic background. The proportion of males per litter was not adversely affected by IL-10 deficiency. Taken together, our work and others suggest that IL-10 may not be critically important for maternal tolerance of the fetus and extends the evidence against the idea that successful mouse pregnancy depends on TH-2 deviation of the maternal immune system.

Autonomic dysfunction may be an under-recognized cause of female fertility disorders

Female conditions of impaired fertility comprise a heterogeneous group of disorders that are attributed to various anatomic, hormonal and immunologic disturbances. We hypothesize that autonomic dysfunction may be a previously unrecognized factor in female fertility disorders. Emerging physiologic and molecular evidence suggests that autonomic balance varies during normal menstrual cycles with a shift to sympathetic bias during the luteal phase. Furthermore, many diseases associated with autonomic dysfunction show catamenial variations in patterns consistent with a shift to sympathetic bias occurs during the second half of normal menstrual cycles. The shift to sympathetic bias during the normal luteal phase may be an evolutionary adaptation to address the immunologic and physiologic demands for successful implantation and gestation. Through direct modulation of the lymphoid system and activation of the cortisol pathway, sympathetic bias promotes a shift to relative T helper (Th)-2 biased immunity which may favor maternal tolerance of the embryo by attenuating Th-1 mediated interference of implantation. Indeed, a growing body of evidence has implicated abnormal Th balance in fertility disorders, but the link has been attributed to factors other than autonomic function, such as hormonal factors. After implantation, maternal sympathetic bias may further support gestation through physiologic changes necessary to maintain placental perfusion pressure. We propose that insufficient shift to sympathetic bias during the luteal phase, which manifests in inadequate shift towards Th-2 bias and down-regulation of Th-1 function, may be the mechanism of impaired fertility in certain patients. Our hypothesis portends new potential methods to treat fertility disorders by modulating autonomic balance.

Effect of ovaric hyper-stimulation on blood lymphocyte subpopulations, cytokines, leptin and nitrite among patients with unexplained infertility

PROBLEM

To determine the effect of ovarian stimulation on TH1, TH2 and natural killer (NK) lymphocytes, plasma cytokines, leptin and nitrite levels.

METHODS

Women with reproductive failure were studied during the implantation window, at baseline (n = 18) and under ovarian stimulation (gonadotropins + progesterone, n = 6).

CONTROLS

eight fertile women. Lymphocyte subpopulations and NK function were determined by flow cytometry. Interleukin-2 (IL-2), IL-4, IL-10, IFN-gamma, TNF-alpha, TGF-beta1 and leptin were measured by enzyme immunoassay (EIA); nitrite by the Griess reaction.

RESULTS

At baseline, patients had higher values of NK effectors, NK activity and plasma IFN-gamma and IL-2 than controls. Conversely, TGF-beta1 values were lower. Hormones induced leukocytosis. Under stimulation, THI CD4+ cells, NK effectors and function and plasma IFN-gamma and IL-2 decreased, while transforming growth factor (TGF)-beta1 increased. Other variables did not change.

CONCLUSION

The abnormal distribution of leukocytes, high TH1 cytokines and a low TGF-beta1 associated with reproductive failure, respond to ovarian stimulation, achieving total or partial normalization.

Cytokines in implantation

Implantation is a complex process which involves the 'invasion' of the maternal endometrium by the trophoblast surrounding the developing blastocyst. In response to this interaction there is a cellular reaction within the endometrium which has some features analogous to invasion by a tumour and some which are more characteristic of an inflammatory response. In addition, and also in common with cancer and inflammation, there is a release of biologically active molecules, including cytokines, at and around the implantation site. The information on cytokines is complex and often contradictory but it is recognised that they play an important role in the successful establishment of pregnancy. The evidence for this role is examined in this review.