Coagulation parameters predictive of repeated implantation failure in Chinese women: A retrospective study.

Repeated implantation failure (RIF) greatly influences pregnancy rate after assisted reproductive technologies (ART) with elusive causes. Our study aimed to explore coagulation parameters in association with RIF and establish a model to predict the risk of RIF in Chinese women.Coagulation parameters, including prothrombin time (PT), thrombin time (TT), activated partial prothrombin time (APTT), D-dimer (DD), fibrin degradation products (FDP), fibrinogen (FG), and platelet aggregation induced by arachidonic acid (AA) and adenosine diphosphate (ADP) were measured in RIF patients and controls. A logistic regression model was built by using the purposeful selection to select important factors for the prediction of RIF.Between 92 RIF patients and 47 controls, we found a statistically significant difference in all of the coagulation parameters except APTT, FDP and platelet aggregation induced by ADP. The purposeful selection method selected PT (odds ratio [OR] = 0.28, 95% CI: 0.12-0.66, P = .003), APPT (odds ratio [OR] = 0.76, 95% CI: 0.63-0.91, P = .004), TT (odds ratio [OR] = 0.75, 95% CI: 0.53-1.08, P = .124), and platelet aggregation induced by AA (odds ratio [OR] = 1.27, 95% CI: 1.11-1.44, P = .0003) as important predictors of RIF risk. ROC curve analysis indicated that the area under ROC curve (AUC) of the model was 0.85 with an optimal cut-off point of the predicted probability being P = .65, leading to a sensitivity of 0.83 and a specificity 0.75.We found that coagulation parameters including PT, APTT, TT and platelet aggregation induced by AA are predictive of RIF in Chinese women. Our results highlight the potential of anti-coagulation therapies to lower the risk of RIF.

Decreased ANGPTL4 impairs endometrial angiogenesis during peri-implantation period in patients with recurrent implantation failure.

Insufficient endometrial angiogenesis during peri-implantation impairs endometrial receptivity (ER), which contributes to recurrent implantation failure (RIF) during in vitro fertilization and embryo transfer (IVF-ET). Angiopoietin-like protein 4 (ANGPTL4) acts as a multifunctional secretory protein and is involved in the regulation of lipid metabolism and angiogenesis in various tissues including the endometrium. Herein, we found decreased ANGPTL4 expression in endometrial tissue and serum during peri-implantation period in 18 RIF-affected women with elevated uterine arterial impedance (UAI) compared with the pregnancy controls. ANGPTL4 and peroxisome proliferator-activated receptor gamma (PPARγ) expression were up-regulated upon decidualization on human endometrial stromal cells (HESCs). Rosiglitazone promoted the expression of ANGPTL4 in HESCs and human umbilical vein endothelial cells (HUVECs) via PPARγ. ANGPTL4 promoted the proliferation, migration and angiogenesis of HUVECs in vitro. Our results suggest that decreased abundance of ANGPTL4 in endometrial tissues impairs the endometrial receptivity via restraining endometrial angiogenesis during decidualization; while rosiglitazone-induced ANGPTL4 up-regulation in hESCs and HUVECs through PPARγ. Therefore, ANGPTL4 could be a potential therapeutic approach for some RIF-affected women with elevated UAI.

Longitudinal profiles of relaxin and progestagens during pregnancy, pregnancy loss and false pregnancy in the killer whale (Orcinus orca).

The circulating pattern of immunoreactive relaxin and progestagens based on monthly and gestational stage (early, mid, late) profiles were determined during pregnancies that resulted in live calves (LIVE, n = 30), stillbirths (STILLB, n = 3), abortions (ABORT, n = 5) and presumptive false pregnancies (FALSE, n = 8), and during the follicular (n = 34) and luteal phase (n = 58). Monthly LIVE relaxin concentrations steadily increased during gestation, but values did not significantly exceed those of the luteal phase until 9 months prior to parturition, peaking during the final month at 2356 ng/ml. Relaxin surged (P < 0.05) during the final week of gestation (36,397 ng/ml), undergoing a 3 and 9-fold increase compared with concentrations in the preceding two weeks, respectively. Monthly relaxin production did not differ among each reproductive state with the exception of months-13-16 where concentrations were higher (P < 0.001) for STILLB than LIVE. Relaxin concentration was reduced (P < 0.0001) by 849% in placental versus maternal serum collected within 1 day of labor. Mid- and late-pregnancy progestagen concentrations were lower for FALSE (P < 0.001) compared with STILLB and LIVE. Late pregnancy progestagen concentrations were reduced for FALSE (P < 0.05) and ABORT (P < 0.02) compared with LIVE and STILLB. Monthly progestagen production in ABORT tended to be lower than LIVE across a range of gestational months (Months 2, 7, 8, 11) but this difference only became significant during months 14 and 15. Results indicate that relaxin is primarily produced by the CL during pregnancy, and that concentrations could not be used to differentiate from non-pregnant females until the final 6 months of gestation. In addition, as would be expected from a primarily CL product, relaxin cannot be used to detect abnormal pregnancies. Conversely, progestagens, which are produced by both the placenta and CL can be used to differentiate FALSE from normal pregnancy and may be useful indicators of fetal health in the killer whale.

Embryotoxic cytokines-Potential roles in embryo loss and fetal programming.

Cytokines in the reproductive tract environment at conception mediate a dialogue between the embryo and maternal tissues to profoundly influence embryo development and implantation success. Through effects on gene expression and the cell stress response, cytokines elicit an epigenetic impact with consequences for placental development and fetal growth, which in turn affect metabolic phenotype and long-term health of offspring. There is substantial evidence demonstrating that pro-survival cytokines, such as GM-CSF, CSF1, LIF, HB-EGF and IGFII, support embryos to develop optimally. Less attention has been paid to cytokines that adversely impact embryo development, including the pro-inflammatory cytokines TNF, TRAIL and IFNG. These agents elicit cell stress, impair cell survival and retard blastocyst development, and at sufficiently high concentrations, can cause embryo demise. Experiments in mice suggest these so-called 'embryotoxic' cytokines can harm embryos through pro-apoptotic and adverse programming effects, as well as indirectly suppressing uterine receptivity through the maternal immune response. Embryotrophic factors may mitigate against and protect from these adverse effects. Thus, the balance between embryotrophic and embryotoxic cytokines can impart effects on embryo development and implantation, and has the potential to contribute to endometrial 'biosensor' function to mediate embryo selection. Embryotoxic cytokines can be elevated in plasma and reproductive tract tissues in inflammatory conditions including infection, diabetes, obesity, PCOS and endometriosis. Studies are therefore warranted to investigate whether excessive embryotoxic cytokines contribute to infertility and recurrent implantation failure in women, and compromised reproductive performance in livestock animals.

Maternal serum amyloid A level as a novel marker of primary unexplained recurrent early pregnancy loss.

OBJECTIVE: To assess maternal serum amyloid A (SAA) levels among women with primary unexplained recurrent early pregnancy loss (REPL). METHODS: A prospective study was conducted among women with missed spontaneous abortion in the first trimester at Ain Shams University Maternity Hospital, Cairo, Egypt, between January 21 and December 25, 2014. Women with at least two consecutive primary unexplained REPLs and no previous live births were enrolled. A control group was formed of women with no history of REPL who had at least one previous uneventful pregnancy with no adverse outcomes. Serum samples were collected to measure SAA levels. The main outcome was the association between SAA and primary unexplained REPL. RESULTS: Each group contained 96 participants. Median SAA level was significantly higher among women with REPL (50.0 µg/mL, interquartile range 26.0-69.0) than among women in the control group (11.6 µg/mL, interquartile range 6.2-15.5; P<0.001). The SAA level was an independent indicator of primary unexplained REPL, after adjusting for maternal age and gestational age (odds ratio 1.12, 95% confidence interval 1.06-1.19; P<0.001). CONCLUSION: Elevated SAA levels found among women with primary unexplained REPL could represent a novel biomarker for this complication of pregnancy.

Monitoring of embryonic and fetal losses in different breeds of goats using real-time B-mode ultrasonography.

Compared to cattle and sheep, few studies had been undertaken to evaluate the incidence of embryonic and fetal losses (EFL) in goats. The objectives of the present study were to characterize the timing of EFL and to identify the factors that are associated with EFL in goats such as breed, age, parity, method of estrous synchronization, and breeding. Moreover, this study aimed to ensure whether a relationship existed between serum progesterone (P4) and EFL. Goats (n = 151) of different breeds (70 Zaraiebi, 42 Damascus, and 39 Cross goats [Baladi × Damascus]) were evaluated by ultrasonography to monitor EFL during different stages of gestation (D20-23, D26-29, D33-36, D40-45, and D47-54 after breeding). Blood samples were collected at D7, D20, and at each ultrasonographic scanning to clarify changes of serum P4 levels concurrently with EFL. Results revealed that 45 of 109 goats (41.28%) were exposed to EFL. A higher EFL % was observed between D20 to 23 and D47 to 54 (19.61%) compared with D47 to 54 to birth (11.76%). Moreover, a higher EFL % was observed in Zaraiebi goats compared with others. Age and goat parity had no significant effect on the EFL % in all goats. A high EFL % were observed in goats synchronized by P4 sponge, as well as artificially inseminated goats compared with goats with spontaneous estrus, and bred by natural mating, respectively. Serum P4 at D7 or D20 after breeding showed nonsignificant difference between normal pregnant goats and goats that experienced EFL. Unlike goats that experienced partial EFL, goats that experienced total EFL between D20 to 23 and D26 to 29 showed an abrupt P4 reduction (85.06%; P < 0.01) suggesting the probability of endocrine disruption of the CL. However, goats that were exposed to total EFL between D26 and 29 to D33 to 36 showed a low P4 reduction (24.90%; P < 0.05), which might be considered as an effect rather than a cause of EFL. In conclusion, different factors such as breed, estrous synchronization, breeding, and stage of pregnancy may be involved in EFL in goats. Therefore, improvement of the goat management in the early stage of pregnancy is important to decrease EFL % in goats. Although the P4 did not show any significant difference between normal pregnancy goats and goats that experienced EFL, CL disruption should be taken into the consideration, at least, in goats exposed to total embryonic losses.

[Reproductive problems in women with PCOS, the impact of PAL-1 CARRIERS OF 4G PAI -1 polymorphism and BMI].

Approximately 7-12% of women in reproductive age are affected by PCOS[2] and 40 to 70 percent of them are overweight contributing to the clinical picture of PCOS and increased reproductive and metabolic disorder. In order to investigate the role of PAl-1 as a possible risk factor for the development of PCOS a group of 67 women with polycystic ovarian disease and 70 healthy controls were investigated for levels of PAI-1 and carriage of the promoter polymorphism 675 4G/5G in gene of PAl-1. The results of the DNA analysis showed a high carriage of polymorphism 675 4G/4G in promoter of PAI-1 gene in women with PCOS but not as significant (OR = 1.6645, p = 0.141). Serum levels of PAI-1 were significantly higher in total group of patients compared to controls. The levels of PAI-1 is correlated with carriage of 675 4G/5G polymorphism in the gene for PAI-1 (R = 0.534, p = 0.03) as well as wih BMI, like correlation coefficients were higher in the group with PCOS (0.572, p = 0.04). Data from the disease history showed a higher percentage of women with reproductive problems: 61.5% (early pregnancy loss and infertility) significantly higher in the group with PCOS (70.1% compared to 54.1%). The carriers of polymorphism 4G are at greater risk for early pregnancy loss than those with 5G (61.45% as compared to 36.8%), which confirms that carriage of the polymorphism 4G/5G 675 gene PAI-1 has a specific in multifactorial pathogenesis and expression of PCOS.

Progesterone is essential for protecting against LPS-induced pregnancy loss. LIF as a potential mediator of the anti-inflammatory effect of progesterone.

Lipopolysaccharide (LPS) administration to mice on day 7 of gestation led to 100% embryonic resorption after 24 h. In this model, nitric oxide is fundamental for the resorption process. Progesterone may be responsible, at least in part, for a Th2 switch in the feto-maternal interface, inducing active immune tolerance against fetal antigens. Th2 cells promote the development of T cells, producing leukemia inhibitory factor (LIF), which seems to be important due to its immunomodulatory action during early pregnancy. Our aim was to evaluate the involvement of progesterone in the mechanism of LPS-induced embryonic resorption, and whether LIF can mediate hormonal action. Using in vivo and in vitro models, we provide evidence that circulating progesterone is an important component of the process by which infection causes embryonic resorption in mice. Also, LIF seems to be a mediator of the progesterone effect under inflammatory conditions. We found that serum progesterone fell to very low levels after 24 h of LPS exposure. Moreover, progesterone supplementation prevented embryonic resorption and LPS-induced increase of uterine nitric oxide levels in vivo. Results show that LPS diminished the expression of the nuclear progesterone receptor in the uterus after 6 and 12 h of treatment. We investigated the expression of LIF in uterine tissue from pregnant mice and found that progesterone up-regulates LIF mRNA expression in vitro. We observed that LIF was able to modulate the levels of nitric oxide induced by LPS in vitro, suggesting that it could be a potential mediator of the inflammatory action of progesterone. Our observations support the view that progesterone plays a critical role in a successful pregnancy as an anti-inflammatory agent, and that it could have possible therapeutic applications in the prevention of early reproductive failure associated with inflammatory disorders.

Predictive value of serum human chorionic gonadotropin ratio, progesterone and inhibin A for expectant management of early pregnancies of unknown location.

OBJECTIVE: To evaluate serum human chorionic gonadotropin (hCG) ratio, progesterone and inhibin A as single parameters and in combination for the prediction of spontaneous resolution of pregnancies of unknown location (PUL). STUDY DESIGN: Prospective observational study of 105 consecutive patients with a diagnosis of PUL. Serum levels of hCG, progesterone and inhibin A were determined at the first visit and after 2 days. Patients were followed clinically until a final diagnosis of spontaneously resolving PUL, viable or non-viable intrauterine pregnancy, or ectopic pregnancy with need of laparoscopic intervention had been reached. Different combinations of hCG ratio (hCG at 48 h/hCG at 0 h), s-progesterone and s-inhibin A were investigated to find the best predictor for successful expectant management. RESULTS: The final pregnancy outcomes were: 52 spontaneously resolving PUL (49.5%), 37 viable intrauterine pregnancies (35.2%), 8 non-viable intrauterine pregnancies (7.6%), 7 ectopic pregnancies (6.7%), and one molar pregnancy (1.0%). An hCG ratio<0.80 predicted spontaneously resolving PUL with positive and negative predictive values (PPV and NPV), sensitivity, and specificity of 0.98, 0.78, 0.72, and 0.99, respectively. In patients with hCG ratio ≥ 0.80, a combination of s-progesterone < 20 nmol/l and s-inhibin A < 30 pg/ml predicted spontaneously resolving PUL with PPV, NPV, sensitivity and specificity of 0.92, 0.96, 0.85, and 0.98 respectively. CONCLUSION: Our results suggest that patients with PUL and hCG ratio < 0.80 display a high probability of spontaneously resolving PUL with minimum need of follow-up. In cases of hCG ratio ≥ 0.80, a combination of s-progesterone < 20 nmol/l and s-inhibin A < 30 pg/ml, may be a reliable predictor of spontaneously resolving PUL. The safety of this approach should be tested in large prospective studies.

Candidate biomarkers for acute rejection of pregnancy after in-utero cell-based therapy in pre-immune embryos via ultrasound-guided celocentesis.

PROBLEM: A maternal serum biomarker profile analysis was performed to determine potential indicators of acute rejection of pregnancy following in-utero cell-based treatments in pre-immune embryos. METHOD OF STUDY: We used an established non-human primate model for in-utero stem cell therapy at 38-42 days from fertilization. The maternal serum concentrations of nine candidate biomarkers for acute rejection of pregnancy were determined before and after the injection of different cocktails of human umbilical cord blood stem cells into the gestational sac. All animals were then followed until delivery. RESULTS: Twenty-four hours after celocentesis, two of the animals aborted. These two animals received a cocktail of haemopoietic stem cells with the highest concentration of human CD3(+) cells and showed a twofold increase in maternal serum IL-6 and a threefold increase in prolactin after the procedure. The remaining six animals delivered at term live and normal newborns and only demonstrated an increase in prolactin after the celocentesis procedure. CONCLUSION: IL-6 and prolactin are master immunoregulators with pleiotropic biological functions that have different maternal serum concentrations depending on pregnancy outcome. These findings suggest that increases in maternal serum prolactin and IL-6 concentration may be associated with acute rejection of pregnancy after in-utero stem cell therapy.

Soluble Flt-1 and PlGF: new markers of early pregnancy loss?

Recent data have indicated a relationship between placental oxygen and angiogenic protein levels in the first trimester of normal pregnancies. Our objective was to investigate if maternal serum levels of angiogenic factors Soluble vascular endothelial growth factor (VEGF) receptor 1 (sFlt-1), soluble Endoglin and placental growth factor (PlGF) are altered in women with symptoms of threatened miscarriage (TM) and if they are predictive of a subsequent miscarriage. Blood samples were collected at 6-10 weeks from women presenting with TM (n = 40), from asymptomatic controls (n = 32) and from non- pregnant women in their luteal phase (n = 14). All samples were assayed for serum level of sFLT-1, PlGF, sEndoglin and HSP70 using commercial ELISAs. Samples were analysed retrospectively on the basis of pregnancy outcome. TM group included 21 women with a normal pregnancy outcome and 19 with subsequent complete miscarriage. The latter subgroup had significantly lower mean maternal serum (MS) sFlt-1 (83%, P<0.001) and PlGF (44%, P<0.001) compared to those with a normal pregnancy outcome. Asymptomatic control pregnant women had similar MS levels of sFlt-1 and PlGF compared to the TM patients with a normal outcome. The mean MS sFlt-1 (>10 fold) and MS PlGF (∼2 fold) levels were significantly (P<0.001) higher in control pregnant women compared to the non-pregnant group in the luteal phase of the menstrual cycle. Soluble Endoglin was not altered in the normal pregnant women compared to non pregnant women, although lower in the TM subgroup with a subsequent miscarriage (∼25%, P<0.001) compared to TM with a live birth. There was no significant difference in the mean MS HSP 70 levels between the different groups. This study shows that sFlt1 and PlGF MS levels are increased by several folds in early pregnancy and that MS sFlt-1 and MS PlGF are markedly decreased in threatened miscarriage patients who subsequently have a miscarriage suggesting these proteins are sensitive predictive markers of subsequent pregnancy loss.

Serum levels of acute phase proteins: SAA, Hp and progesterone (P4) in mares with early embryonic death.

The study involved 46 healthy purebred Arabian mares exhibiting regular oestrous cycles that underwent artificial insemination (AI). Pregnancy was detected ultrasonographically (US) in 40 mares. In 15 mares in foal, early embryonic death (EED) was observed during the pregnancy days 14-21. Blood for determinations of serum acute phase proteins (SAA and Hp) and progesterone (P4) was sampled 12-24 h before ovulation and the first insemination, at 12, 24, 72, 96 h and on day 7, 10, 14, 21, 35 and 55 after ovulation. The results revealed that in 25 mares without EED, the serum levels of P4, SAA and Hp were within physiological limits; in 15 mares with EED, the levels of SAA and Hp were significantly increased. In seven mares with EED, high levels of SAA and Hp were already found before ovulation and at 12, 24, 72, 96 h as well as on day 7 and 10 post-ovulation, whereas the level of P4 was normal for early pregnancy. In the remaining eight mares with EED, increased levels of SAA and Hp were found at 72 h after ovulation and maintained until day 55. In this group, the level of P4 decreased since 96 h after ovulation. Determinations of SAA, Hp and P4 in mares in early pregnancy (EP) are useful for monitoring normal development of pregnancy and for diagnosis of subclinical genital inflammations, which may lead to EED.

Anomalous pregnancies during late embryonic/early foetal period in high producing dairy cows.

This study analyses anomalous cases of gestation ending in pregnancy loss during the early foetal period and their effect on progesterone and plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations. Data derived from a large-scale ultrasound pregnancy diagnosis programme in high producing dairy cows. Over a 3-year period (2004-2007), a very low incidence (0.5%: 15 of 3094) of anomalous pregnancies was recorded. The results revealed that the following anomalies were detected on days 35-41 of gestation in cows carrying singletons with one single corpus luteum: embryo death in eight cows (0.3%); and embryo in the uterine horn contralateral to the corpus luteum in seven cows (0.2%). All these animals suffered pregnancy loss during the early foetal period. In cows carrying dead embryos, no signs of conceptus degeneration were observed on pregnancy diagnosis. Amnion size (approximately 25 mm diameter) and uterine horn fluid contents were estimated to be similar to those of the normal pregnant cows in this period. In the contralateral gestations, live embryos were observed in all ultrasound checks before pregnancy loss. Uterine fluid contents increased in the two cows in which gestation continued for more than a week. In the cases of embryo death but not in those of contralateral gestation, a drop in PAG-1 levels was noted prior to pregnancy loss. Two cows carrying dead embryos increased with time allantoic fluid contents. The PAG-1 values increased with time in one cow bearing a dead embryo (from 2.31 to 6.79 ng/ml) and in two of the contralateral gestations (from 1.66 to 2.33 ng/ml and from 0.39 to 6.79 ng/ml, respectively). Results of this study indicate that the foetal membranes continue to undergo some activity following embryo death, and that contralateral pregnancy may determine failure of the gestation process.

Plasma progesterone concentrations during early pregnancy in spring- and autumn-bred ewes.

The objective of this experiment was to measure blood progesterone concentrations during early gestation to determine if the apparent reproductive failure in ewes bred out-of-season is due to a failure to conceive or embryonic loss. Blood samples were collected from spring- (n=61) and autumn-bred ewes (n=29) from Days 8 to 39 post-oestrus. Serum progesterone concentrations were analysed to ascertain whether ewes were ovulating and failing to maintain pregnancy, or conception was failing. Following pregnancy diagnosis 62 days after ram introduction, ewes were categorised as; no display of oestrus, mated but then identified as non-pregnant, or pregnant. A majority of spring-bred ewes that failed to display oestrus had silent oestrus (86%) and 66% of those ewes had abnormally short-lived corpora lutea. Circulating progesterone concentrations during dioestrus in ewes that had ovulated and displayed oestrus were unaffected by season. Similarly, progesterone concentrations during dioestrus did not differ between pregnant and mated non-pregnant ewes. The results indicated that while early luteylosis, low progesterone secretion from corpora lutea and embryo mortality did occur, these were in only a small proportion of ewes. Progesterone concentrations indicated that a majority of mated non-pregnant ewes had elevated progesterone concentrations necessary for the production of at least one viable embryo/foetus. This may be indicative to the failure of maternal recognition of pregnancy, and it is recommended that events surrounding this stage of pregnancy (Days 12-14) be examined more closely in ewes during the non-breeding season.

Perfluorooctanoic acid induced developmental toxicity in the mouse is dependent on expression of peroxisome proliferator activated receptor-alpha.

Perfluorooctanoic acid (PFOA) is a member of a family of perfluorinated chemicals that have a variety of applications. PFOA persists in the environment and is found in wildlife and humans. In mice, PFOA is developmentally toxic producing mortality, delayed eye opening, growth deficits, and altered pubertal maturation. PFOA activates peroxisome proliferators-activated receptor-alpha (PPARalpha), a pathway critical to the mode of induction of liver tumors in rodents. The present study uses 129S1/SvlmJ wild-type (WT) and PPARalpha knockout (KO) mice to determine if PPARalpha mediates PFOA-induced developmental toxicity. Pregnant mice were dosed orally from gestation days 1-17 with water or 0.1, 0.3, 0.6, 1, 3, 5, 10, or 20 mg PFOA/kg. PFOA did not affect maternal weight, embryonic implantation, number, or weight of pups at birth. At 5 mg/kg, the incidence of full litter resorptions increased in both WT and KO mice. In WT, but not KO, neonatal survival was reduced (0.6 mg/kg) and eye opening was delayed (1 mg/kg). There was a trend across dose for reduced pup weight (WT and KO) on several postnatal days (PND), but only WT exposed to 1 mg/kg were significantly different from control (PND7-10 and 22). Maternal factors (e.g., background genetics) did not contribute to differences in postnatal mortality, as PFOA induced postnatal mortality in heterozygous pups born to WT or KO dams. In conclusion, early pregnancy loss was independent of PPARalpha expression. Delayed eye opening and deficits in postnatal weight gain appeared to depend on PPARalpha expression, although other mechanisms may contribute. PPARalpha was required for PFOA-induced postnatal lethality and expression of one copy of the gene was sufficient to mediate this effect.

Patterns of late embryonic and fetal mortality and association with several factors in sheep.

Embryonic and fetal mortality reduce lambing rates and litter sizes, thus contributing to economic losses in the sheep industry. In the current study, the timing of late embryonic and fetal loss in ewes and the factors with which these losses were associated were examined. Ewes lambing and lambs born were compared with pregnancy diagnosis and counts of embryos by ultrasonography near d 25, 45, 65, or 85 of gestation. Approximately 19.9% of the ewes experienced late embryonic loss, fetal loss, or both; and 21.2% of the embryos or fetuses were lost from d 25 to term. Potential offspring were lost throughout gestation; 3.7% of embryos from d 25 to 45, 4.3% of fetuses from d 45 to 65, 3.3% from d 65 to 85, and 11.5% from d 85 to parturition; thus, approximately 3 to 4% of the potential offspring were lost for each 20-d period of pregnancy beyond d 25. A greater proportion of ewes lost one (36.7%) rather than all (20.5% single; 3.8% multiple) embryos or fetuses. The patterns of loss were similar in ewes mated during the anestrous season and the transitional period and did not vary with service period within breeding season or method of synchronization of estrus. Late embryonic or fetal losses were not related to the temperature-humidity index. Maternal serum collected near d 25, 45, 65, or 85 of gestation was assayed for concentrations of progesterone, estradiol-17beta , and vascular endothelial growth factor (VEGF). The proportions of embryos or fetuses lost were associated with breed type (P < 0.05), as were concentrations of progesterone (P < 0.01), estradiol (P < 0.05), and VEGF (P < 0.01). The relationships of loss or retention of pregnancy to hormonal variables at the 4 stages studied were limited. Complete and partial losses increased rapidly as maternal progesterone at d 25 decreased below 2 ng/mL (P < 0.05). Survival of fetuses within a litter from d 25 to 65 was greater for ewes with medium concentrations of VEGF near d 25 and from d 65 to parturition was greater for ewes with high concentrations of VEGF near d 45 (P < 0.05). In summary, late embryonic or fetal losses occurred from d 25 throughout gestation and varied with breed type and with concentrations of progesterone in maternal serum on d 25.

Retinoblastoma promotes definitive erythropoiesis by repressing Id2 in fetal liver macrophages.

In mammals, the fetal liver is the first site of definitive erythropoiesis-the generation of mature, enucleated red cells. The functional unit for definitive erythropoiesis is the erythroblastic island, a multicellular structure composed of a central macrophage surrounded by erythroblasts at various stages of differentiation. Targeted disruption of the retinoblastoma (Rb) tumour suppressor gene in the mouse leads to embryonic death caused by failure of erythroblasts to enucleate. The erythroid defect has been attributed to loss of Rb in cells that support erythropoiesis, but the identity of these cells is unknown. Here we show that Rb-deficient embryos carry profound abnormalities of fetal liver macrophages that prevent physical interactions with erythroblasts. In contrast, wild-type macrophages bind Rb-deficient erythroblasts and lead them to terminal differentiation and enucleation. Loss of Id2, a helix-loop-helix protein that mediates the lethality of Rb-deficient embryos, rescues the defects of Rb-deficient fetal liver macrophages. Rb promotes differentiation of macrophages by opposing the inhibitory functions of Id2 on the transcription factor PU.1, a master regulator of macrophage differentiation. Thus, Rb has a cell autonomous function in fetal liver macrophages, and restrains Id2 in these cells in order to implement definitive erythropoiesis.

Preovulatory, postovulatory, and postmaternal recognition effects of concentrations of progesterone on embryonic survival in the cow.

Although fertilization rate usually is very high when male fertility is normal, pregnancy rates are below expectations when defined by the birth of live offspring in response to first service. Factors that affect establishment and retention of pregnancy include 1) preovulatory influences on the follicle and oocyte, 2) early postovulatory uterine and luteal function, 3) concentrations of hormones associated with trophoblastic and endometrial function during maternal recognition of pregnancy, and 4) less-well understood factors during the peri-attachment period. For example, decreased progesterone during preovulatory follicular development leads to a persistent follicle, premature resumption of meiosis, and a high incidence of embryonic death between the 2- and 16-cell stages. Elevated PGF(2alpha) during d 4 to 9 of the estrous cycle not only caused luteolysis but also had a direct embryotoxic effect during the morula-to-blastocyst transition. Ideal conditions during placentation and attachment are not clearly defined. Late embryonic mortality might be increased after ovulation of persistent or immature follicles. Nominal increases in secretion of PGF(2alpha) between d 30 and 35 might be important for attachment and placentation. Lower survival of embryos from wk 5 to wk 7 to 9 of gestation in the cow was associated with lower circulating concentrations of progesterone on wk 5. To maximize embryonic survival in the cow, management must provide high progesterone before estrus, quality detection of estrus, and timely insemination. Luteolytic influences of estradiol-17beta or PGF(2alpha) must be minimized early after mating and during maternal recognition of pregnancy, and high progesterone is needed during the late embryonic/early fetal period.

No association of C677T methylenetetrahydrofolate reductase and an endothelial nitric oxide synthase polymorphism with recurrent pregnancy loss.

PROBLEM: It is controversial whether polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and the endothelial nitric oxide synthase (eNOS) are associated with recurrent pregnancy loss. METHOD OF STUDY: We studied the frequency of the C677T polymorphism of MTHFR and a eNOS gene polymorphism, as well as the plasma levels of homocysteine and NO, in 85 cases with a history of two or more unexplained embryonal losses, 40 patients suffering fetal loss and 76 controls. RESULTS: The frequency of the MTHFR gene T allele, which has been reported to be associated with miscarriages, in patients suffering fetal loss was rather significantly lower than in controls whereas there was no difference in the frequency of the eNOS gene A allele. There were no differences in the plasma homocysteine levels among the three groups. However, the NO concentrations in the embryonal loss and fetal loss groups were significantly higher than that in controls. CONCLUSION: We conclude that the NO concentration but not the polymorphism of MTHFR and eNOS gene and hyperhomocysteinemia are associated with recurrent pregnancy loss in Japanese.