Fetal growth in the baboon during the second half of pregnancy

The normal growth profile of critical fetal organs through the last third of gestation has not been documented in detail in human fetuses or the fetus of any nonhuman primate species. Recent epidemiological studies in human pregnancy suggest that fetal growth plays a major role in the programming of life-long health by modifying cardiovascular, pancreatic, brain, and liver growth. The present study aimed to produce a detailed database of individual organ growth in the fetal baboon in late gestation. Fetal organ weights were obtained from 43 baboon fetuses between 121 and 177 days of gestation. Various organs (brain, heart, kidney, femur, intestines, and spinal cord) showed no sign of slowed growth in late gestation while growth of others (lung, liver, stomach, and bladder) accelerated in late gestation. The fetal adrenal and thymus showed a decrease in growth rate over the final 20 and 10 days of gestation respectively. These observations provide a database that will permit analysis of factors responsible for regulation of normal and altered fetal organ development in this important experimental species.     

Relative abundance of human placental phospholipase A2 messenger RNA in late pregnancy.

The aim of this study was to determine messenger RNA (mRNA) levels for a specific phospholipase A2 (PLA2) in human placenta during late gestation prior to the onset of labour. The relative abundance of human placental mRNA for a nonpancreatic Group II PLA2 was determined using cDNA clone specific for this PLA2. Twenty seven placentae were collected from women undergoing elective (i.e. before the onset of labour) Caesarean section between 37 and 41 completed weeks gestation. The relative amount of human placental PLA2 mRNA did not change significantly over this period of late pregnancy (p greater than 0.8). Previously, we have demonstrated that placental PLA2 messenger RNA levels are increased in association with spontaneous onset labour at term in the human. The data obtained in this current study are consistent with the conclusion that the regulation of this human placental PLA2 gene is tightly controlled around the time of parturition and that its expression is increased acutely in association with labour.     

Ultrasonography in early pregnancy diagnosis and measurements of fetal size in reindeer (Rangifer tarandus tarandus)

Transrectal or transabdominal examinations of 13 pluriparous reindeer (Rangifer tarandus tarandus) by ultrasonography from the start of mating until week 20 of gestation were conducted to find out when pregnancy could first be detected and to describe fetal development in early pregnancy. The examinations (n=35 per animal) were performed with a 5 MHz linear transducer from 7th October until 1st January and with a 3 MHz sector transducer from that time until 24th February. Time of pregnancy diagnosis by ultrasonography, the first fetal heartbeat and measurements of crown-rump length, chest width and chest depth were recorded during the examinations. Pregnancy was diagnosed by transrectal ultrasonography between the weeks 3 and 7 of gestation. The accuracy of the pregnancy diagnosis, defined as the proportion of females correctly detected to be pregnant, was 15% at week 3, 46% at week 4, 77% at week 5, and 92% at week 6 of gestation. Fetal heartbeat was first detected between the weeks 5 and 8 of gestation. The first measurements of crown-rump length were made on week 3 of gestation, of chest width on week 4 and of chest depth on week 5 of gestation. Chest width and depth were detectable until the end of the study at week 20 of gestation. Transrectal ultrasonography is an efficient tool in early pregnancy diagnosis of reindeer. The fetal growth curves obtained by ultrasonography resembled those obtained in previous morphological studies.     

Ontogeny of hematological cell and biochemical profiles in maternal and fetal baboons (Papio species)

The normal ranges of hematological cell profiles and biochemistry are documented in adult non-pregnant, pregnant, juvenile, and neonatal baboons. Despite the extensive use of the baboon as a model for the study of various aspects of pregnancy, there is no data from paired mothers and their fetuses at different stages of gestation. Hematologic and biochemical profile data were obtained from eight non-pregnant female baboons, 37 mothers and 38 fetal baboons at 30 +/- 2, 90 +/- 2, 125 +/- 2, and 175 +/- 2 days of gestation (mean +/- range; dGA; term, 180 dGA). Changes observed in fetal and maternal blood during normal baboon pregnancy were similar to those reported in human pregnancy. The level of alkaline phosphatase was two times higher in fetal blood circulation than that reported in human pregnancy.     

Fetal cells in the maternal circulation during first trimester in pregnancies

To investigate the presence of fetal cells in the maternal circulation during early pregnancy, the polymerase chain reaction was used to test the presence of human Y chromosome-specific ZFY and SRY gene DNA sequences in maternal peripheral blood specimens from 19 women carrying male fetuses and 12 women carrying female fetuses. The presence of fetal cells was suggested as early as 6 weeks gestation in 1 of the 19 women bearing male fetuses. Fetal cells were present in the maternal circulation of 15 of the 19 women by 9 weeks gestation, and in only 1 of the 19 were fetal cells not detected until the 12th week after conception. These results suggest that identification of fetal cells in the maternal circulation is possible with a properly designed and executed polymerase chain reaction. However, there was considerable variation with respect to when these fetal cells first became detectable during pregnancy. These fetal cells are potentially a valuable source of material for biochemical and genetic studies of the fetuses.     

Type I collagen synthesis by human osteoblasts in response to placental lactogen and chaperonin 10, a homolog of early-pregnancy factor

Recent studies have indicated that maternal skeletal metabolism undergoes significant changes during gestation. The agents that are responsible for eliciting these changes in bone turnover during pregnancy have yet to be defined. We therefore sought to investigate whether chaperonin 10 (Cpn10), a homolog of early-pregnancy factor, or human placental lactogen (PL) were capable of influencing the synthesis of type I collagen by human osteoblasts in vitro. Both Cpn10 and PL are major components of the maternal circulation during pregnancy, but how they might contribute to bone metabolism has not been determined. Type I collagen represents the most abundant component of bone tissue, accounting for approximately 90% of the organic compartment. Both Cpn10 and PL were capable of stimulating the synthesis of type I collagen by human osteoblasts in culture. The inclusion of 17 beta-estradiol or prolactin, however, failed to influence the ability of cells to mobilize type I collagen. These novel findings support a role for PL and Cpn10 in the metabolism of bone tissue during pregnancy. Maternal bone collagen metabolism is clearly an important event during pregnancy, and the identification of the factors responsible will aid our understanding of the regulation of skeletal metabolism during gestation.     

Glycogen metabolism in human fetal testes

The ontogeny of glycogen synthetase, glycogen Phosphorylase and α-D-glucosidase, enzymes which are associated with glycogen metabolism and glycogen level has been studied in human fetal testes of gestational age ranging from 14–32 weeks. Glycogen synthetase activity reaches the peak value at 17–20 weeks of gestation, thereafter it decreases. α-D-Glucosidase activity increases with the advancement of pregnancy up to 28 weeks of gestation decreasing thereafter very rapidly. Phosphorylase activity remains more or less constant throughout gestation. The maximum increase in glycogen content at early stages of gestation (17–20 weeks) and gradual reduction with the advancement of pregnancy are correlated with histochemical observation by the periodic acid-Schiff technique.     

Fertility of frozen-thawed porcine semen following controlled-rate freezing in straws

A method was developed for freezing large batches of porcine semen in straws at a controlled rate in a liquid nitrogen programmable freezer. The fertilizing potential of spermatozoa frozen by this method was examined by inseminating 220 sows with a mixture of semen from two boars. Estrus was synchronized using one of two regimens and sows were inseminated once at 34 h after human chorionic gonadotropin (hCG) treatment. The average pregnancy rate at 60 d of gestation, farrowing rate and litter size were 60.9%, 51.4% and 8.8, respectively. The fertilizing potential of spermatozoa frozen by this method appeared to be similar to that reported for other methods of freezing porcine semen.     

Development, validation, and application of a urinary relaxin radioimmunoassay for the diagnosis and monitoring of pregnancy in felids

Many nondomestic felids are highly endangered, and captive breeding programs have become essential components of holistic conservation efforts for these species. The ability to diagnose pregnancy early in gestation is fundamental to developing effective breeding programs. The purpose of this study was to develop a radioimmunoassay (RIA) for the detection of urinary relaxin in felids and assess its applicability for early, noninvasive pregnancy diagnosis in domestic cats (Felis silvestris catus) and leopards (Panthera pardus). Urine was collected from pregnant and nonpregnant domestic cats and leopards at mating, and then weekly thereafter for the duration of gestation. Paired serum samples were also collected from the domestic cats. A RIA for relaxin that uses an antiserum against synthetic canine relaxin was validated for felid urine and shown to detect relaxin immunoreactivity in pregnant cat urine subjected to acid-acetone extraction. In the cat, urinary relaxin was first detected between Days 21 and 28 of gestation; levels peaked at 42-49 days, and the concentrations then declined over 2 wk prior to parturition. The urinary relaxin profiles of the cat mirrored those in serum. In the leopard, urinary relaxin was first detected at Day 25-28 of gestation; levels peaked at Day 60-64 and declined in the last 3-4 wk of pregnancy. These results indicate that measurement of urinary relaxin in the cat and leopard provides a reliable method for pregnancy determination from as early as 3-4 wk of gestation. This method of pregnancy diagnosis and monitoring may prove useful in the breeding management of domestic cats and other felid and canid species, and provides a foundation for future studies on pregnancy in captive exotic carnivores.     

Immunolocalisation of the uterine secretory proteins uterocalin, uteroferrin and uteroglobin in the mare's uterus and placenta throughout pregnancy

Previous studies have shown that the equine uterus produces many progesterone-dependent proteins throughout gestation. In particular, uterocalin and uteroferrin are detectable using electrophoresis or blot analyses but information regarding the immunohistochemical placental distribution of these two proteins is rare and information regarding uteroglobin is still lacking. The aim of the present study was to co-immunolocalise these three secretory proteins in the mare's uterus throughout gestation in an effort to understand their functional role in the maintenance of pregnancy. Therefore, endometrial biopsy samples were obtained from 20 pregnant mares between 16 and 309 days of gestation and labelled immunohistochemically for uteroglobin, uteroferrin and uterocalin. Uteroferrin remained detectable in almost every endometrial gland at all stages but with an increase in staining intensity as gestation advanced. The most progesterone-dependent protein, uterocalin, showed variable staining throughout gestation with the most intense labelling in early pregnancy and during the period of endometrial cup reaction. Uteroglobin secretion was only detectable in traces and only in individual glands throughout gestation. The results indicate that uterocalin and uteroferrin, but not uteroglobin, may play important roles in supplying nutrients for the conceptus, thereby contributing to the maintenance of pregnancy. However, further investigations are necessary to understand the role of uteroglobin during gestation.     

A mathematical model of maternal vascular growth and remodeling and changes in maternal hemodynamics in uncomplicated pregnancy

The maternal vasculature undergoes tremendous growth and remodeling (G&R) that enables a?>?15-fold increase in blood flow through the uterine vasculature from conception to term. Hemodynamic metrics (e.g., uterine artery pulsatility index, UA-PI) are useful for the prognosis of pregnancy complications; however, improved characterization of the maternal hemodynamics is necessary to improve prognosis. The goal of this paper is to develop a mathematical framework to characterize maternal vascular G&R and hemodynamics in uncomplicated human pregnancies. A validated 1D model of the human vascular tree from the literature was adapted and inlet blood flow waveforms at the ascending aorta at 4 week increments from 0 to 40 weeks of gestation were prescribed. Peripheral resistances of each terminal vessel were adjusted to achieve target flow rates and mean arterial pressure at each gestational age. Vessel growth was governed by wall shear stress (and axial lengthening in uterine vessels), and changes in vessel distensibility were related to vessel growth. Uterine artery velocity waveforms generated from this model closely resembled ultrasound results from the literature. The literature UA-PI values changed significantly across gestation, increasing in the first month of gestation, then dramatically decreasing from 4 to 20 weeks. Our results captured well the time-course of vessel geometry, material properties, and UA-PI. This 1D fluid-G&R model captured the salient hemodynamic features across a broad range of clinical reports and across gestation for uncomplicated human pregnancy. While results capture available data well, this study highlights significant gaps in available data required to better understand vascular remodeling in pregnancy.

     

Comparative hemostatic protein alterations accompanying pregnancy and parturition

Pregnancy and parturition represent adaptive, physiological stress situations that elicit both blood coagulation protein changes and endocrine alterations. This paper briefly reviews the interrelationships of these responses by comparing the available data in several mammalian species including man, dog, cow, and pig. Hemostasis is an enzymatically controlled cascade process involving platelets and specific coagulation proteins that results in the formation of insoluble strands of fibrin. Although qualitatively similar in most mammals, quantitative differences exist in the circulating levels of individual coagulation proteins which may contribute towards the different rates of clot formation. In the late gestation stage of human pregnancy, significant increases are observed in the circulating biological activities of the coagulation factors VII, VIII:C, IX, and X. In the dog, the activities of factors VII and IX reach peak values in midpregnancy, while in the cow little or no changes are observed except for factor VII values which show a significant increase only around the time of parturition. These coagulation changes appear to be associated with fluctuations in circulating hormone values, particularly plasma estrogen. In human pregnancy, the circulating levels of fibrinogen, the precursor of fibrin, increase during the gestation period reaching maximum values during and immediately following parturition. In the dog and the cow two distinct increases in fibrinogen values are observed, the first in the midgestation period and the second in the immediate postparturition period. In the pig, fibrinogen values also rise significantly at parturition. Oral contraceptive studies in the human female have indicated that changes in circulating activities of coagulation proteins are hormonally influenced.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endocannabinoids,hormone-cytokine networks and human fertility

Anandamide (N -arachidonoylethanolamine, AEA) is a major endocannabinoid, shown to impair mouse pregnancy and embryo development and to induce apoptosis in blastocysts. Here, we review the roles of AEA, of the AEA-binding cannabinoid (CB) receptors, of the selective AEA membrane transporter (AMT), and of the AEA-hydrolyzing enzyme fatty acid amide hydrolase (FAAH), in human gestation. In particular, we discuss the interplay between the endocannabinoid system and the hormone-cytokine array involved in the control of human pregnancy, showing that the endocannabinoids take part in the immunological adaptation occurring during early pregnancy. In this line, we discuss the critical role of FAAH in human peripheral lymphocytes, showing that the expression of this enzyme is regulated by progesterone, Th1 and Th2 cytokines, which also regulate fertility. Moreover, we show that AEA and the other endocannabinoid, 2-arachidonoylglycerol, inhibit the release of the fertility-promoting cytokine leukemia inhibitory factor from human lymphocytes. Taken together, low FAAH and consistently high blood levels of AEA, but not CB receptors or AMT, can be early (<8 weeks of gestation) markers of spontaneous abortion, potentially useful as diagnostic tools for large-scale, routine monitoring of gestation in humans.     

The Lin28/Let-7 System in Early Human Embryonic Tissue and Ectopic Pregnancy

Our objective was to determine the expression of the elements of the Lin28/Let-7 system, and related microRNAs (miRNAs), in early stages of human placentation and ectopic pregnancy, as a means to assess the potential role of this molecular hub in the pathogenesis of ectopic gestation. Seventeen patients suffering from tubal ectopic pregnancy (cases) and forty-three women with normal on-going gestation that desired voluntary termination of pregnancy (VTOP; controls) were recruited for the study. Embryonic tissues were subjected to RNA extraction and quantitative PCR analyses for LIN28B, Let-7a, miR-132, miR-145 and mir-323-3p were performed. Our results demonstrate that the expression of LIN28B mRNA was barely detectable in embryonic tissue from early stages of gestation and sharply increased thereafter to plateau between gestational weeks 7–9. In contrast, expression levels of Let-7, mir-132 and mir-145 were high in embryonic tissue from early gestations (≤6-weeks) and abruptly declined thereafter, especially for Let-7. Opposite trends were detected for mir-323-3p. Embryonic expression of LIN28B mRNA was higher in early stages (≤6-weeks) of ectopic pregnancy than in normal gestation. In contrast, Let-7a expression was significantly lower in early ectopic pregnancies, while miR-132 and miR-145 levels were not altered. Expression of mir-323-3p was also suppressed in ectopic embryonic tissue. We are the first to document reciprocal changes in the expression profiles of the gene encoding the RNA-binding protein, LIN28B, and the related miRNAs, Let-7a, mir-132 and mir-145, in early stages of human placentation. This finding suggests the potential involvement of LIN28B/Let-7 (de)regulated pathways in the pathophysiology of ectopic pregnancy in humans.     

Excessive ovarian follicular development in pregnant pigtailed macaques (Macaca nemestrina)

To evaluate the status and possible control of ovarian follicular development during pregnancy, circulating levels of estrone (E₁), estradiol-17β (E₂), and follicle-stimulating hormone (FSH) were measured throughout gestation in both intact and ovariectomized pregnant pigtailed monkeys (Macaca nemestrina). From an additional group of pregnant monkeys, ovaries were obtained at late gestation (on day 150 or 159 of pregnancy) for histological studies. Circulating concentrations of E₁ and E₂ increased on day 13 and remained elevated for about 10 days; they then declined and reached low levels on day 32 of gestation. After day 60, there were gradual but smaller increases in estrogen levels to day 140, after which both E₁ and E₂ levels increased significantly, reaching maximum levels (E₁ = 832.2 ± 210.8 pg/ ml; E₂ = 1.66 ± 0.32 ng/ml) at the end of pregnancy. Removal of ovaries on day 35 of gestation did not affect pregnancy or the pattern of estrogen secretion. Serum concentrations of FSH demonstrated only minor fluctuations during pregnancy but were similar to those found during the early follicular phase of cycling pigtailed monkeys investigated in this study. Ovarian histology revealed extensive follicular growth; in addition to the corpus luteum of pregnancy, ovaries were packed with pre-antral, small antral, and medium-sized Graafian follicles. Some of these follicles appeared to be cystic and showed various degree of atresia; their general appearance was similar to the follicles of human females with polycystic ovary syndrome. Our data suggest that FSH may initiate ovarian follicular growth during gestation. High levels of estrogens were incapable of suppressing FSH secretion but may be responsible for the induction of atresia in a large number of follicles in pregnant pigtailed monkeys.     

Consumption of Distinct Dietary Lipids during Early Pregnancy Differentially Modulates the Expression of microRNAs in Mothers and Offspring

Diet during pregnancy and lactation influences the offspring’s health in the long-term. Indeed, human epidemiological studies and animal experiments suggest that different type of fatty acids consumption during pregnancy affect offspring development and susceptibility to metabolic disorders. Epigenetic changes are thought to be elicited by dietary factors during critical timing of development. microRNAs (miRNAs) are versatile regulators of gene expression. Thus, we aimed to determine the influence of different fatty acids on miRNA expression in offspring when given during early pregnancy. We fed pregnant either soybean (SO), olive (OO), fish (FO), linseed (LO), or palm-oil (PO) diets from conception to day 12 of gestation; and standard diet thereafter. miRNA expression was assessed in liver an adipose tissue of pregnant rats and their virgin counterparts. While liver concentrations of fatty acids in pregnant or virgin rats replicated those of the diets consumed during early pregnancy, their pups’ liver tissue marginally reflected those of the respective experimental feeds. By contrast, the liver fatty acid profile of adult offsprings was similar, regardless of the diet fed during gestation. Different parental miRNAs were modulated by the different type of fatty acid: in adult offspring, miR-215, miR-10b, miR-26, miR-377-3p, miR-21, and miR-192 among others, were differentially modulated by the different fatty acids fed during early pregnancy. Overall, our results show that maternal consumption of different types of fatty acids during early pregnancy influences miRNA expression in both maternal and offspring tissues, which may epigenetically explain the long-term phenotypic changes of the offspring.     

Low Gestational Weight Gain Skews Human Sex Ratios towards Females

Background

Human males are more vulnerable to adverse conditions than females starting early in gestation and continuing throughout life, and previous studies show that severe food restriction can influence the sex ratios of human births. It remains unclear, however, whether subtle differences in caloric intake during gestation alter survival of fetuses in a sex-specific way. I hypothesized that the ratio of male to female babies born should vary with the amount of weight gained during gestation. I predicted that women who gain low amounts of weight during gestation should produce significantly more females, and that, if gestational weight gain directly influences sex ratios, fetal losses would be more likely to be male when women gain inadequate amounts of weight during pregnancy.

Methods

I analyzed data collected from over 68 million births over 23 years to test for a relationship between gestational weight gain and natal sex ratios, as well as between gestational weight gain and sex ratios of fetal deaths at five gestational ages.

Results

Gestational weight gain and the proportion of male births were positively correlated; a lower proportion of males was produced by women who gained less weight and this strong pattern was exhibited in four human races. Further, sex ratios of fetal losses at 6 months of gestation were significantly male-biased when mothers had gained low amounts of weight during pregnancy, suggesting that low caloric intake during early fetal development can stimulate the loss of male fetuses.

Conclusion

My data indicate that human sex ratios change in response to resource availability via sex-specific fetal loss, and that a pivotal time for influences on male survival is early in fetal development, at 6 months of gestation.     

The effect of human chorionic gonadotrophin and exogenous progesterone on luteal function during early pregnancy in pony mares

Previous reports have indicated that repeated administrations of human chorionic gonadotrophin (hCG) to pony mares before day 38 of gestation caused pregnancy failure, but that this could be prevented by the prior or simultaneous administration of progesterone. The present paper describes the circulating progestagen concentrations during these experiments, and shows that pregnancy failure resulted from luteolysis after hCG administration. Most of the mares which received progesterone maintained their pregnancies after hCG injection, but progestagen concentrations fell, suggesting that partial lysis of the corpus luteum occurred. After day 38 of gestation repeated doses of hCG had no effect on plasma progestagen concentrations.     

The role of n-3 fatty acids in gestation and parturition

Preterm birth is the most common cause of low infant birth weight and infant morbidity and mortality. Evidence from human and animal studies indicates that essential fatty acids of both the n-3 and n-6 series, and their eicosanoid metabolites, play important and modifiable roles in gestational duration and parturition, and n-3 fatty acid intake during pregnancy may be inadequate. Prostaglandins (PG) of the 2-series are involved in parturition and connective tissue remodeling associated with cervical maturation and rupture of membranes. In the absence of infections, preterm birth is characterized by lower reproductive tissue PG production and decreased inducible cyclooxygenase expression. Women who deliver prematurely have increased pools of n-6 fatty acid and decreased n-3 fatty acids, despite the lower PG production. Several human pregnancy supplementation trials with n-3 fatty acids have shown a significant reduction in the incidence of premature deliver and increased birth weight associated with increased gestational duration. Supplementation with long chain n-3 fatty acids such as docosahexaenoic acid may be useful in prolonging the duration of gestation in some high-risk pregnancies. Evidence presented in this review is discussed in terms of the roles of dietary n-3 and n-6 fatty acids in gestation and parturition, mechanisms by which they may influence gestational duration and the human trials suggesting that increased dietary long-chain n-3 fatty acids decrease the incidence of premature delivery.     

Hydrops fetalis caused by intrauterine human parvovirus infection

During a large outbreak of erythema infectiosum in 1987 in Toyama prefecture, Japan, a 32-year-old woman acquired a mild rash on her arms and legs at 18 weeks of gestation. At 26 weeks and 4 days of gestation, the fetus died by hydrops fetalis and pregnancy was terminated. Histological studies of the fetus revealed degeneration of erythroblastic cells in the liver and bone marrow. Extensive extramedullary hematopoiesis and hemosiderin deposits were observed in the liver. Antibody response to human parvovirus B19 virus was demonstrated in maternal sera by ELISA. Furthermore, dot hybridization with the molecularly cloned DNA probe revealed the presence of human parvovirus DNA sequence in the fetal liver, spleen, lung, kidney and placenta. This report describes the first case in Japan of hydrops fetalis caused by human parvovirus B19 infection.