The immune function of the endometrium

Gynecological surgery in adulthood imparts cognitive and brain changes in rats: A focus on hysterectomy at short-, moderate-, and long-term intervals after surgery

Premenopausal hysterectomy is associated with a greater relative risk of dementia. We previously demonstrated cognitive impairments in adult rats six weeks after hysterectomy with ovarian conservation compared with intact sham-controls and other gynecological surgery variations. Here, we investigated whether hysterectomy-induced cognitive impairments are transient or persistent. Adult rats received sham-control, ovariectomy (Ovx), hysterectomy, or Ovx-hysterectomy surgery. Spatial working memory, reference memory, and anxiety-like behavior were tested either six-weeks post-surgery, in adulthood; seven-months post-surgery, in early middle-age; or twelve-months post-surgery, in late middle-age. Hysterectomy in adulthood yielded spatial working memory deficits at short-, moderate-, and long-term post-surgery intervals. Serum hormone levels did not differ between ovary-intact, but differed from Ovx, groups. Hysterectomy had no significant impact on healthy ovarian follicle or corpora lutea counts for any post-surgery timepoint compared with intact sham-controls. Frontal cortex, dorsal hippocampus, and entorhinal cortex were assessed for activity-dependent markers. In entorhinal cortex, there were alterations in FOSB and ΔFOSB expression during the early middle-age timepoint, and phosphorylated ERK1/2 levels at the adult timepoint. Collectively, results suggest a primary role for the uterus in regulating cognition, and that memory-related neural pathways may be modified following gynecological surgery. This is the first preclinical report of long-term effects of hysterectomy with and without ovarian conservation on cognition, endocrine, ovarian, and brain assessments, initiating a comprehensive framework of gynecological surgery effects. Translationally, findings underscore critical needs to decipher how gynecological surgeries, especially those involving the uterus, impact the brain and its functions, the ovaries, and overall aging from a systems perspective.

An immunohistochemical study of the localization and developmental expression of ghrelin and its functional receptor in the ovine placenta

BACKGROUND

Ghrelin is an orexigenic hormone principally produced by the stomach, but also by numerous peripheral tissues including the placenta. Ghrelin acts via growth hormone secretagogue receptors (GHSR-1a) to alter food intake, fat utilization, and cellular proliferation, and has been suggested to play a role in the developmental growth of the fetoplacental unit. The placental expression of ghrelin and its role in ruminant species is not known. We tested the hypotheses that ghrelin and its functional receptor, GHSR-1a, are present in tissues of the ovine placenta, and that their expression is linked to the stage of development.

METHODS

Antibodies raised against ghrelin and GHSR-1a were used in standard immunohistochemical protocols on placental tissues collected from pregnant ewes (n = 6 per gestational time point) at days 50, 80, 100, 128 and 135 of gestation (term approximately day 145). Immunostaining for ghrelin and GHSR-1a was quantified using computer-aided image analysis. Image analysis data were subjected to one-way ANOVA, with differences in immunostaining between time-points determined by Fisher's least significant difference.

RESULTS

Positive immunostaining for ghrelin was detected in ovine placentae at all gestational time points, with staining localized to the maternal epithelium, caruncle and trophectoderm. There was a significant effect of gestational age (p < 0.001) on the placental expression of ghrelin, with maximal levels at gestational day 80. GHSR-1a immunostaining was detected in the fetal trophectoderm at all time points. In contrast to the gestational pattern of ghrelin expression, there was no effect of gestational age on placental GHSR-1a immunoexpression.

CONCLUSION

Ghrelin and GHSR-1a are both present in the ovine placenta, and ghrelin displays a developmentally-related pattern of expression. Therefore, these data strongly suggest that the ghrelin system may have a role in feto-placental development in sheep.

Influence of early ICSI-derived embryo sHLA-G expression on pregnancy and implantation rates: a prospective study

BACKGROUND

We have previously reported the retrospective observation that when at least one embryo, transferred on day 3, expressed sHLA-G above the geometric mean (sHLA-G+) 46 h post-ICSI, there was a marked improvement in both pregnancy (PR) and implantation (IR) rates.

METHODS

The media surrounding individual embryos derived from ICSI performed on oocytes from 482 women < or =43 years of age were tested for sHLA-G expression by specific ELISA.

RESULTS

We report here prospective results showing improved IVF results following the transfer of 'good quality' embryos (7-9 cells with <20% fragmentation) by preferentially including at least one sHLA-G+ embryos. PR and IR for women < or =38 years were 63% and 32% when one transferred embryo was sHLA-G+, and 69% and 36% when at least two embryos were sHLA-G+. When none of the embryos transferred was sHLA-G+, PR and IR were 25% and 13%, respectively. Comparable PR and IR for women 39-43 years were 29% and 11% when none of the transferred embryos were sHLA-G+; 38% and 15% when at least one sHLA-G+ embryo was transferred; and 61% and 26% when at least two 2 sHLA-G+ embryos were transferred. The data were stratified by patient age.

CONCLUSIONS

PR and IR increased with the addition of each sHLA-G+ embryo, regardless of age. While there are significant barriers to routine embryo sHLA-G testing, we believe that if implemented, this would provide a mechanism for optimizing IVF PR while minimizing the risk of multiple pregnancies.

Estradiol regulation of secretory component: expression by rat uterine epithelial cells

Sex hormones are known to play an important role in the regulation of mucosal immunity in the female reproductive tract. The purpose of this study was to examine the effect of estradiol (E2) on secretory component (SC) expression by epithelial cells in the rat uterus and to determine whether SC mRNA is present in uterine tissues and is under hormonal control. When ovariectomized rats treated with E2 for 3 days and sacrificed 12 h after the last injection, expression of SC on luminal and glandular epithelial cells, as determined by immunohistochemistry, was elevated when compared to control animals. To determine whether E2 regulation of SC involves mRNA synthesis, uterine RNA was extracted and analyzed by Northern blot. These experiments demonstrated that SC RNA is present in uteri from intact rats and markedly increased when ovariectomized animals are treated with E2. In other studies, uterine epithelial cells from adult rats were isolated and grown on permeable membranes for 5 to 10 days. Under these conditions, isolated epithelial cells grow to confluence, form tight junctions, and preferentially secrete SC into the apical medium. These studies identify epithelial cells as a key target cell in the uterus for the regulation of mucosal immunity by E2, which we postulate will play an important role in studies to prevent and/or control the spread of sexually transmitted diseases.

Macrophages and migratory cells in endometrium relevant to implantation

The implantation of an appropriately developed embryo into a suitably conditioned uterine lining depends on the synchronous maturation of the preimplantation embryo and uterine lining. The pre- and postimplantation embryo also requires protection from immunocompetent maternal immune effectors. Preimplantation embryo development is affected by genotype, intercellular communication and autocrine growth factors (polyamines, TGF-alpha, TGF-beta 1, PAF). Factors of maternal origin may also enhance embryo development (EGF, TGF-alpha, TGF-beta 1, IGF, polyamines). The preimplantation embryo signals its presence to the mother by release of factor(s) such as IFN-alpha-II and a PAF-like factor. PAF may induce EPF in the mother and enhances vascular permeability at the implantation site. Uterine or peritoneal leukocytosis may inhibit development via toxic effects of lymphokines/monokines (IL-2, IL-1?, IFN-gamma, TNF-alpha). Immunoprotection of the preimplantation embryo is conferred by embryo derived maternal factors (EPF, T-cell suppressor factors). The uterus is receptive during a limited period of time (implantation window) and the substrate adhesion molecules produced by uterine and embryonic trophectoderm cells are crucial for the initial stages of implantation. At implantation, trophoblast expression of MHC and non-MHC antigens is shut off and both immunocompetent maternal cells (macrophages, dendritic cells, granulocytes, IELs, immunocytes) and lymphatics become sparse at implantation sites. Peri-implantation cytokines of maternal origin, such as CSF-1, GM-CSF and IGF-1 binding protein, are probably important for trophoblast growth and development. Immuno-protection of the embryo at this stage may be mediated by embryo derived factors that inactivate macrophages and by a population of large, hormone dependent Lyt 2+ (CD8+) suppressor cells. It is possible that these CD8+ cells respond to progesterone and secrete molecules that inactivate natural effector (NK-type) cells against trophoblast. Prostaglandins (PGE2) may play a brief role in immunosuppression at the time of implantation but its role is probably more important with respect to the decidual response. Defects in the pre- and peri-implantation stages of pregnancy may lead to delayed failure in the form of clinical miscarriage.