Placental protein 13 and decidual zones of necrosis: an immunologic diversion that may be linked to preeclampsia

We evaluated the role of placental protein 13 (PP13; galectin 13) in the process of trophoblast invasion and decidual necrosis. Immunohistochemical analysis for PP13, immune cells, human placental lactogen, cytokeratin, and apoptosis markers was performed on 20 elective pregnancy termination specimens between 6 and 15 weeks of gestation. Placental protein 13 was localized to syncytiotrophoblasts in the chorionic villi and to occasional multinucleated luminal trophoblasts within converted decidual spiral arterioles. Cytotrophoblasts, anchoring trophoblasts, and invasive trophoblasts did not stain for PP13. Extracellular PP13 aggregates were found around decidual veins associated with T-cell-, neutrophil- and macrophage-containing decidual zones of necrosis (ZONEs). We hypothesize that PP13 is secreted into the intervillus space, drains through the decidua basalis veins, and forms perivenous PP13 aggregates which attract and activate maternal immune cells. Thus, syncytiotrophoblast-derived PP13 may create a ZONE that facilitates trophoblast invasion and conversion of the maternal spiral arterioles.

Determination of placental weight using two-dimensional sonography and volumetric mathematic modeling

An abnormally decreased placental weight has been linked to increased perinatal complications, including intrauterine fetal demise (IUFD) and fetal growth restriction (IUGR). Despite its promise, determining placental weight prenatally using three-dimensional systems is time-consuming and requires expensive technology and expertise. We propose a novel method using two-dimensional sonography that provides an immediate estimation of placental volume. Placental volume was calculated in 29 third-trimester pregnancies using linear measurements of placental width, height, and thickness to calculate the convex-concave shell volume within 24 hours of birth. Data were analyzed to calculate Spearman's rho (r (s)) and significance. There was a significant correlation between estimated placental volume (EPV) and actual placental weight (r (s) = 0.80, P < 0.001). Subgroup analysis of preterm gestations ( N = 14) revealed an even more significant correlation of EPV to actual placental weight (r (s) = 0.89, P < 0.001). Placental weight can be accurately predicted by two-dimensional ultrasound with volumetric calculations. This method is simple, rapid, and accurate, making it practical for routine prenatal care, as well as for high-risk cases with decreased fetal movement and IUGR. Routine EPV surveillance may decrease the rates of perinatal complications and unexpected IUFD.

Timing of fetal meconium absorption by amnionic macrophages

This study sought to determine the time interval from fetal defecation to membrane staining and subsequent meconium uptake by amnionic macrophages. Pieces of external membranes were fastened to Teflon rings to create a well. The amnionic surface was exposed to meconium and amniotic fluid for 1 to 48 hours and analyzed microscopically for the presence of free meconium and meconium-laden amnionic macrophages. In each of the experiments, prior to the 12-hour time point, few meconium-laden macrophages were present in the membrane layers. A significant rise in the number of meconium-laden macrophages and a concomitant increase in staining intensity was noted in the membranes at 24 and 48 hours. Contrary to previous reports, our in vitro model of meconium incorporation into placental membranes demonstrated that significant numbers of meconium-laden macrophages were only observed after 24 and 48 hours.

IFPA meeting 2008 workshops report

Workshops are an important part of the IFPA annual meeting. At the IFPA meeting 2008 diverse topics were discussed in 12 themed workshops. Topics covered included: immunology of placentation; galectins and trophoblast invasion; signaling in implantation and invasion; markers to identify trophoblast subpopulations; placental pathology; placental toxicology; stereology; placental transport of fatty acids; placental mesenchymal stem cells; comparative placentation; trophoblast and neoplasia; trophoblast differentiation. This report is a summary of the various topics covered.

The fetus, not the mother, elicits maternal immunologic rejection: lessons from discordant dizygotic twin placentas

AIMS

Our objective was to elucidate the pathogenesis of twin discordance in four dizygotic pregnancies where only one of the twins had IUGR due to chronic villitis.

METHODS

We identified four cases of dizygotic twin placentas over a period of four years with evidence of chronic villitis. There was no clinical or pathologic evidence of TORCH, bacterial infection, preeclampsia or autoimmune disorders. Placentas were weighed, processed for histologic examination and stained with CD45RO (clone UCHL1) mouse monoclonal antibody, which identifies T-cells.

RESULTS

All placentas were dichorionic, with two being fused. Birth weight differences were 29%, 41%, 17% and 10%. Villitis was more marked in the placenta of the twin that weighed less and correlated with the degree of weight discordance. On examining the junction between the fused dichorionic placentas, the chorionic villi from the smaller twin contained numerous T-cells, whereas the villi associated with the less affected twin, showed little to no T-cells.

CONCLUSION

We describe a series of dizygotic twin placentas where the more severe the chronic villitis, the more affected the placenta and fetus. Since the maternal environment was constant for each of these twins, differences in villitis severity appears to be attributable to differences in the ability of each placenta to induce a maternal immune response.

Histological characteristics of singleton placentas delivered before the 28th week of gestation

AIMS

The placenta is a record of the fetal environment and its examination may provide information about the baby's subsequent growth and development. We describe the histological characteristics of 947 singleton placentas from infants born between 23 and 27 weeks gestation.

METHODS

Consent was obtained from mothers who delivered before 28 weeks (clinical estimate). We evaluated the gross and histopathological features of the placenta and assessed pair-wise correlations between variables.

RESULTS

Lesions of uteroplacental circulation (abruption, extensive infarction or thrombosis, marked basal or perivillous fibrin deposition, increased syncytial knots) were inversely related to those associated with inflammation of the membranes and cord. Earlier age favoured inflammatory variables, while older age favoured characteristics attributed to impaired blood flow. We observed inflammation of the chorionic plate in 43%, the cord in 19%, and of chorionic plate vessels in 30%. Of the placentas with umbilical cord inflammation, 8% had no inflammation of the chorionic plate.

CONCLUSIONS

This study population is unique in its size and recruitment by gestational age rather than birth weight. Inflammation occurred frequently, but not in placentas that had characteristics of vasculopathy. The prevalence of inflammation decreased with increasing gestational age, while vasculopathy increased. Funisitis need not be accompanied by chorionic inflammation.

GnRH antagonists may affect endometrial receptivity

OBJECTIVE

HOXA10 is an essential regulator of endometrial receptivity. To determine the effect of GnRH antagonists on endometrial receptivity, we assessed endometrial HOXA10 expression in GnRH antagonist, GnRH agonist, and natural cycles.

DESIGN

Prospective case-control study.

SETTING

University academic medical center.

PATIENT(S)

Nineteen subjects were included: 12 subjects underwent controlled ovarian hyperstimulation with recombinant FSH and used either a GnRH antagonist or a GnRH agonist; seven control subjects underwent natural cycles.

INTERVENTION(S)

Pipelle endometrial biopsies were obtained 11 days after hCG administration or spontaneous LH surge in untreated cycles, respectively. Immunohistochemistry was used to assess HOXA10 protein expression in endometrial glands and stroma.

MAIN OUTCOME MEASURE(S)

Endometrial HOXA10 protein expression.

RESULT(S)

HOXA10 expression was significantly decreased in endometrial stromal cells in GnRH antagonist-treated cycles compared with GnRH agonist-treated cycles or natural cycle control subjects. There was no significant difference in glandular cell HOXA10 expression among the three groups.

CONCLUSION(S)

Use of GnRH antagonists may be associated with impaired HOXA10 expression in endometrial stromal cells and thus may affect endometrial receptivity.

Characterization of chorioamnionitis in 2nd-trimester C-section placentas and correlation with microorganism recovery from subamniotic tissues

Prolonged exposure to infection appears to influence fetal/neonatal development. We characterize the relationship between histologic patterns of inflammation and microorganism recovery from the placentas of live born infants delivered before the 28th postmenstrual week. The subamniotic parenchyma of 835 placentas delivered by cesarean section were cultured and evaluated for specific histologic patterns of inflammation in a blinded fashion. Cases with prolonged membrane rupture were excluded. Microorganisms were recovered from 41% of placentas. Microorganisms found more frequently in placentas with high-grade chorionic plate inflammation include Actinomyces, Prevotella bivia, Corynebacterium sp., Escherichia coli, Peptostreptococcus magnus, multiple species of Streptococci, and Mycoplasma sp., including Ureaplasma urealyticum. These microorganisms were also associated with fetal vasculitis (neutrophilic infiltration of chorionic plate stem vessels or umbilical cord). Recovery of microorganisms from placental parenchyma is associated with histologic inflammation. The same microorganisms responsible for inciting high-grade chorionic plate inflammation are also most likely to promote fetal inflammation.

Reference weights for placentas delivered before the 28th week of gestation

CONTEXT

Very few studies have measured the weight of large numbers of placentas delivered before the 28th post-menstrual week.

METHODS

We measured the weight of 930 singleton placentas delivered before the 28th post-menstrual week, and examined the distributions of weights in selected groups (week of gestation, reason for preterm birth, birth weight Z-score categories, placenta histology). We excluded 90 singleton placentas based on growth restriction as indicated by birth weight Z-score, resulting in a normative sample of 840 placentas. Weights for unfused twin placentas are also presented.

RESULTS

Standard weights derived from our data set differ from those previously published, partly due to a larger sample size. Placenta weight varied with birth weight. Placentas from pregnancies ending due to preeclampsia, fetal indications or those showing evidence of poor perfusion on histology were among the smallest and their weights correlated with the smallest birth weights for gestational age.

CONCLUSIONS

Placenta weights appear to be influenced by multiple maternal and fetal processes. We present a standard weight table for singleton placentas among live infants born between 23 and 27 completed weeks.

Placental trophoblast inclusions in autism spectrum disorder

BACKGROUND

Microscopic examination of placental tissue may provide a route to assessing risk and understanding underlying biology of autism.

METHODS

Occurrence of a distinctive microscopic placental morphological abnormality, the trophoblast inclusion, was assessed using archived placental tissue. The rate of occurrence of trophoblast inclusion-positive slides observed for 13 individuals with autism spectrum disorder (ASD) was compared to the rate in an anonymous consecutive birth cohort.

RESULTS

The occurrence of inclusion positive slides was significantly greater in the ASD group compared to the control group (6/27 slides, 22.2% vs. 12/154, 7.8%; Fisher Exact Test, two-tailed p = .033; relative risk 2.85). The proportion of positive cases was also greater in the ASD group (5/13 cases, 38.5% vs. 8/61, 13.1%; Fisher Exact, two-tailed p = .044; relative risk 2.93). Behavioral severity scores did not differ across groups of inclusion positive (N = 4) and negative (N = 8) ASD individuals.

CONCLUSIONS

Although probably not functionally detrimental or causative, the greater occurrence of placental trophoblast inclusions observed in ASD individuals may reflect altered early developmental processes. Further research is required to replicate the basic finding, to understand the basis for the trophoblastic abnormality, and to determine the utility of the measure in early detection of ASD.

Optimization of endometrial preparation results in a normal endometrial function test® (EFT®) and good reproductive outcome in donor ovum recipients

PURPOSE

Numerous studies have investigated potential markers of endometrial receptivity as predictors of successful implantation. Cyclin E and p27 have recently been studied using the endometrial function test (EFT). Our objective is to determine the correlation between the expression of cyclin E and p27 and the adequacy of uterine preparation of recipients using donor oocytes.

METHODS

Twenty recipients undergoing preparatory cycles with leuprolide acetate, estrogen, and progesterone. Endometrial biopsies were obtained 10-12 days after progesterone supplementation following the course of estrogen. The tissue was prepared for histological analysis and immunohistochemical staining for cyclin E assessment. The outcome of their subsequent ovum donation cycle was blinded to the reviewer of the EFT.

RESULTS

All recipients showed normal luteal transformation. Nineteen (95%) of the recipients had a normal EFT. This is significantly higher than what we demonstrated, previously, in unexplained infertility patients, where only 40% of such patients had a normal EFT. Thirteen recipients with a normal EFT had a clinical pregnancy, while 6 did not become pregnant in their subsequent transfer cycles. The sole patient with an abnormal EFT did not conceive on 2 subsequent cycles.

CONCLUSIONS

While a normal EFT does not guarantee a successful pregnancy, an abnormal EFT appears to be associated with pregnancy failure. This may be useful in identifying women who need adjustments to their stimulation protocols prior to progressing to a physically, emotionally, and financially costly cycle.

Mouse ascites Golgi mucin expression abnormalities in natural cycle endometrial biopsies predict subsequent in vitro fertilization–embryo transfer (IVF-ET) failure in patients with previous IVF-ET failures

We performed a double-blinded retrospective cohort study to determine whether endometrial expression of mouse ascites Golgi mucin in a natural, unmedicated cycle predicts subsequent IVF-ET outcome among women with prior IVF-ET failure and poor pre-embryo quality. We found a statistically significant decrease in clinical pregnancy rate among women with abnormal mouse ascites Golgi expression, a test which was found to have high positive predictive value for failed IVF-ET.

HOXA10, Pbx2, and Meis1 protein expression in the human endometrium: formation of multimeric complexes on HOXA10 target genes

HOXA10 is a transcription factor necessary for embryonic uterine development and for adult endometrial receptivity. The three-amino acid loop extension family of cofactors, including Pbx and Meis, provide HOX target gene specificity in development and myeloid differentiation. Here we demonstrate the expression of Pbx and Meis family cofactors in the human endometrium and their interaction with HOXA10. Using immunohistochemical analysis, we found that Pbx2 and Meis1, but not Pbx1, Pbx3, or Meis2, were expressed in human endometrium. HOXA10, Pbx2, and Meis1 were expressed in the stroma throughout the menstrual cycle. The glandular expression of HOXA10 and Meis1 was menstrual cycle stage specific, whereas glandular Pbx2 expression did not vary. Pbx2, but not Meis1, was expressed in Ishikawa cells. EMSA demonstrated HOXA10-Pbx2 binding as a heterodimer to an enhancer of the EMX2 gene, a known target of HOXA10 regulation. Ablation of the Pbx binding site, but not ablation of the HOXA10 binding site in EMX2, resulted in loss of dimer binding. Based on the observed expression and binding patterns of Pbx2, Meis1, and HOXA10, it is likely that heterodimeric and trimeric complexes involving these proteins determine HOXA10 target gene specificity. Enhanced target gene specificity imparted by multimer binding is likely necessary for HOXA10-mediated endometrial receptivity.

A computational model of the mechanics of growth of the villous trophoblast bilayer

We present a computational model of the mechanics of growth of the trophoblast bilayer in a chorionic villous, the basic structure of the placenta. The placental trophoblast is modeled as a collection of elastic neutrally buoyant membranes (mononuclear cytotrophoblasts and multinucleated syncytiotrophoblast) filled with a viscous, incompressible fluid (cytoplasm) with sources of growth located inside cells. We show how this complex, dynamic fluid-based structure can be modeled successfully using the immersed boundary method. The results of our research presented here include simulations of two processes-cell proliferation and cell fusion which both play a crucial role in the growth and development of the trophoblast tissue. We present the computed results of simulations of both processes running independently as well as simultaneously, along with comparisons with clinically obtained results.

Improved endometrial assessment using cyclin E and p27

OBJECTIVE

To evaluate endometrial expression of cyclin E and p27 in fertile and infertile women.

DESIGN

Retrospective clinical study.

SETTING

University medical center and private practice.

PATIENT(S)

Thirty-three fertile volunteers, 83 women seeking infertility treatment, and 23 women undergoing mock cycles.

INTERVENTION(S)

Endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Cyclin E and p27 immunohistochemistry.

RESULT(S)

Glandular cyclin E and p27 expression dramatically changed in intensity and subcellular localization throughout the menstrual cycle. In normal control biopsies, glandular cyclin E progressed from the basal to the lateral cytoplasm (midproliferative phase) to the nucleus (days 18 to 19) and was absent in biopsies after day 20. First appearing on days 17 to 19, p27 was found only in the nuclei. Cyclin E was more frequently seen after day 20 in infertility patients. In the hyperstimulated cycles, staining for cycle E in proliferative samples was more intense than in the natural cycles, but p27 staining was unchanged.

CONCLUSION(S)

Cyclin E and p27 may be clinically useful markers of development in the endometrium. As cell cycle regulators, cyclins reveal underlying biochemical processes driving endometrial progression and may partly represent the means by which estrogen and progesterone regulate this dynamic tissue.

Sexual activity, orgasm and tampon use are associated with a decreased risk for endometriosis

OBJECTIVE

The purpose of the study was to determine if sexual behaviors, orgasm, tampon use, and douching during menstruation modify the risk of endometriosis.

METHODS

A case-control study was conducted. Subjects (n = 2,012) consisted of members of the Endometriosis Association and friends not affiliated with the organization who completed mailed surveys. Data were analyzed using chi(2), Fisher's exact test, t test, and regression analyses.

RESULTS

There was no difference between study groups concerning douching practices. However, cases were less likely than controls to report sometimes or often engaging in sexual behaviors during menstruation (p = 0.002, OR = 1.5), and sexual behaviors during menstruation that included orgasm (p = 0.001, OR = 1.5). Cases were also less likely than controls to report using only tampons (p < 0.0001, OR = 2.6).

CONCLUSION

Sexual activity, orgasm, and tampon use during menstruation may confer protection against endometriosis.

Maternal Hoxa10 is required for pinopod formation in the development of mouse uterine receptivity to embryo implantation

Hoxa10 is a homeobox gene that is expressed both during the embryogenesis of the genitourinary tract and in the adult reproductive tract. Maternal Hoxa10 expression is necessary for endometrial receptivity to blastocyst implantation. The mechanism by which Hoxa10 induces endometrial development to a state of receptivity is unknown as HOXA10-deficient endometrium appears histologically normal. We altered the expression of Hoxa10 in the uterus of cycling adult female mice and examined the uterus at the time of implantation by transmission electron microscopy for alterations in epithelial morphology. Pinopods are projections on the surface of the uterine endometrial epithelial cells that develop transiently at the time of endometrial receptivity. Blocking Hoxa10 expression by transfection of Hoxa10 antisense into the cycling mouse uterus before implantation dramatically decreased pinopod number. Constitutively expressing Hoxa10 in the uterus just before the normal time of pinopod formation resulted in increased pinopod number. Therefore, Hoxa10 is necessary for pinopod development. Hox genes have been implicated in both the regulation of cellular proliferation and the determination of developmental fate. Hoxa10 exemplifies this dual role in the uterus by regulating both endometrial stromal cell proliferation and epithelial cell morphogenesis. Taken together, these results demonstrate that maternal Hoxa10 has an essential role in pinopod development and this function of Hoxa10 likely contributes to endometrial receptivity for the purpose of blastocyst implantation.

Mouse ascites golgi (MAG) mucin expression and regulation by progesterone in the rat uterus

OBJECTIVE

To study the regulation of the blood group A-related high-molecular weight mucin glycoprotein epitope (mouse ascites golgi, MAG)-a menstrual cycle-dependent marker of endometrial receptivity-in a non-human endometrium model.

METHODS

Immature Sprague-Dawley rats were injected with 1 microg of estradiol, 100 microg of testosterone, 100 microg of dexamethasone, 2.5 mg of progesterone (P), 0.325 mg of RU486, P and RU486, 100 microg of tamoxifen, or vehicle for 3 days, sacrificed, and the uteri were stained for MAG. Immunohistochemistry and blood analysis were the measurements used to compare the specimens from the exogenous hormonal and endogenous hormonal groups. Electron microscopy was used to locate the MAG epitope in one pseudopregnant adult Sprague-Dawley rat.

RESULTS

The MAG epitope was present in endometrial glands of Sprague-Dawley rats, with maximal expression during proestrus and diestrus. Electron microscopy confirmed the Golgi location of this MAG epitope. In the untreated group, less than 0.5% of endometrial glands stained for MAG. The MAG was seen only in the glands of the P-treated rats and RU486 blunted this stimulatory effect by more than 95%. As little as 0.1 mg of P promoted MAG expression, with maximal response at 2.5 mg. Staining was seen 24 hours after P treatment, peaked at 72 hours, then declined. Induction of endogenous P by superovulation with pregnant mare serum gonadotropin (PMSG) and hCG (pseudopregnancy) also resulted in strong MAG glandular staining.

CONCLUSION

Our results suggest that the MAG epitope is cyclically expressed and induced by P in rat endometrial glands.

Modulation of leukemia inhibitory factor gene expression and protein biosynthesis in the human fallopian tube

OBJECTIVE

The fallopian tube is the site of fertilization and early embryonic growth and a common site of ectopic implantation. Although the factors responsible for early embryogenesis and implantation are incompletely understood, leukemia inhibitory factor may have an important role in early embryonic development and implantation. We set out to evaluate the production and modulation of leukemia inhibitory factor in the fallopian tube.

STUDY DESIGN

We first investigated leukemia inhibitory factor messenger ribonucleic acid levels in fallopian tubes. We then investigated leukemia inhibitory factor messenger ribonucleic acid and protein production in tubal epithelial and stromal cell cultures.

RESULTS

Leukemia inhibitory factor messenger ribonucleic acid is expressed in the fallopian tube with only slight variation during the menstrual cycle; however, it is markedly elevated in association with ectopic pregnancy. The level is higher in the tubal mucosa than in the remaining layers and is higher in the more distal segments of the fallopian tube. Estradiol and progesterone did not modulate leukemia inhibitory factor expression in epithelial or stromal cell cultures. Interleukin-1 alpha, tumor necrosis factor-alpha, and transforming growth factor-beta enhanced leukemia inhibitory factor expression in epithelial and stromal cells, with transforming growth factor-beta 1 enhancing expression by fourfold in stromal cells. Epithelial cells secreted high levels of leukemia inhibitory factor compared with stromal cells (332 +/- 89 vs 25 +/- 42 pg/mg total protein). Yet stromal cells treated with transforming growth factor-beta alone or in combination with epidermal growth factor and platelet-derived growth factor, as well as TNF-alpha alone or in combination with interleukin-1 alpha enhanced secretion of leukemia inhibitory factor at or above the levels found with epithelial cells.

CONCLUSIONS

We speculate that the high constitutive levels of leukemia inhibitory factor expressed in the ampullary portion of the fallopian tube may play a role in early embryonic development. Additionally, elevated expression with ectopic implantation and the marked induction of secretion in the tubal stroma by growth factors and cytokines suggest a link between inflammation, leukemia inhibitory factor, and tubal ectopic pregnancies.

The effect of leukemia inhibitory factor (LIF) on trophoblast differentiation: a potential role in human implantation

Leukemia inhibitory factor (LIF) is a multifunctional glycoprotein strongly associated with normal implantation in the mouse. We have recently determined that LIF is expressed in the human endometrium in a menstrual cycle dependent manner. Maximal expression is observed between days 19 and 25 of the menstrual cycle, coinciding with the time of human implantation. In this study we have utilized purified cultures of human cytotrophoblasts to examine the effects of LIF on several morphologic and biochemical markers of the trophoblastic differentiation. We purified human cytotrophoblasts from term placentae and cultured them with and without LIF (10 ng/mL). The secretion of human CG, oncofetal fibronectin, and progesterone were measured at 24, 48, 72, and 96 h. Northern blot analysis was used to assess messenger RNA (mRNA) expression of beta hCG and oncofetal fibronectin. We found that LIF markedly decreased trophoblast production of hCG protein at 72 and 96 h, as well as expression of beta hCG mRNA. LIF also significantly increased the expression of oncofetal fibronectin mRNA and secretion of the protein. LIF did not affect steroidogenic activity of cultured trophoblasts, as determined by progesterone production. These biochemical changes are characteristic of cytotrophoblast differentiation toward an anchoring extravillous phenotype. Thus, LIF appears to be an important regulator of human embryonic implantation by directly modulating trophoblast differentiation.