Expression of Aquaporin 1 and Aquaporin 3 in Fetal Membranes and Placenta in Human Term Pregnancies with Oligohydramnios

Genetic improvement of economic traits in Murrah buffalo using significant SNPs from genome-wide association study

GWAS helps to identify QTL and candidate genes of specific traits. Buffalo breeding has primarily focused on milk production, but its negative correlation with reproduction traits resulted in unfavorable decline of reproductive performance among buffaloes. A genome wide scan was performed on a total of 120 Murrah buffaloes genotyped by ddRAD sequencing for 13 traits related to female fertility, production, and growth. The identified 25 significant single nucleotide polymorphisms (SNPs) (P <1×10⁶) are associated with age at first calving (AFC), age at first service (AFS), period from calving to 1^st Artifical Insemination (AI), service period (SP) and 6 month body weight (6M). Fifteen genetic variants overlapped with different QTL regions of reported studies. Among the associated loci, outstanding candidate genes for fertility, including AQP1, TRNAE-CUC, NRIP1, CPNE4, and VOPP1, have effect in different fertility traits. AQP1 gene is expressed in ovulatory phase and various stages of pregnancy. TRNAE-CUC gene is associated with AFC and number . of calvings after 4 years of age. Glycogen content-associated gene CPNE4 regulates muscle glycogen and is upregulated during early pregnancy. NRIP1 generegulates ovulation, corpus luteum at pregnancy, and mammary gland development. The objective is to identify potential genomic regions and genetic variants associated with economic traits and to select the most significant SNP which have positive effect on all the traits.

Importance of Water Transport in Mammalian Female Reproductive Tract

Aquaporins (AQPs) are involved in water homeostasis in tissues and are ubiquitous in the reproductive tract. AQPs are classified into classical aquaporins (AQP0, 1, 2, 4, 5, 6 and 8), aquaglycerolporins (AQP3, 7, 9, and 10) and superaquaporins (AQP11 and 12). Nine AQPs were described in the mammalian female reproductive tract. Some of their functions are influenced by sexual steroid hormones. The continuous physiological changes that occur throughout the sexual cycle, pregnancy and parturition, modify the expression of AQPs, thus creating at every moment the required water homeostasis. AQPs in the ovary regulate follicular development and ovulation. In the vagina and the cervix, AQPs are involved mainly in lubrication. In the uterus, AQPs are mostly mediated by estradiol and progesterone to prepare the endometrium for possible embryo implantation and fetal development. In the placenta, AQPs are responsible for the fluid support to the fetus to maintain fetal homeostasis that ensures correct fetal development as pregnancy goes on. This review is focused on understanding the role of AQPs in the mammalian female reproductive tract during the sexual cycle of pregnancy and parturition.

Aquaporins in Fetal Development

Water homeostasis is essential for fetal growth, and it depends on the successful development of the placenta. Many aquaporins (AQPs) were identified from blastocyst stages to term placenta. In the last years, cytokines, hormones, second messengers, intracellular pH, and membrane proteins were found to regulate their expression and function in the human placenta and fetal membranes. Accumulated data suggest that these proteins may be involved not only in the maintenance of the amniotic fluid volume homeostasis but also in the development of the placenta and fetal organs. In this sense, dysregulation of placental AQPs is associated with gestational disorders. Thus, current evidence shows that AQPs may collaborate in cellular events including trophoblast migration and apoptosis. In addition, aquaglyceroporins are involved in energy metabolism as well as urea elimination across the placenta. In the last year, the presence of AQP9 in trophoblast mitochondria opened new hypotheses about its role in pregnancy. However, much further work is needed to understand the importance of these proteins in human pregnancies.

Feto-placental Unit: From Development to Function

The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.

Efficacy of inhaled Desmopressin in pregnant women with idiopathic oligohydramnios - a randomized controlled trial

The aim of this study was to investigate the therapeutic effect of inhaled Desmopressin (DDAVP) in pregnant women with idiopathic oligohydramnios. This randomized, double-blind clinical trial involved 44 pregnant women at 28-37 weeks of gestation with idiopathic oligohydramnios admitted in 2 academic hospitals in Mashhad, Iran, from 2018 to 2019. In the intervention group, 10µg DDAVP was nasally sprayed. The control group received intravenous maintenance fluid. The hematocrit, electrolytes, blood pressure and urine-specific gravity were evaluated at baseline and 3, 8, and 24 hours later. Amniotic fluid index (AFI) was measured using ultrasound at baseline, 24 and 48 hours later. There was no significant difference in the basic characteristics (age, body mass index, and gestational age) between the two groups. The pattern of changes of AFI (baseline, 24 and 48 hours later) increased in the intervention (4.16±0.86, 7.08±1.453 and 7.76±1.62, p<0.001) and control groups (4.23±0.70, 5.39±1.079 and 5.68±1.10, p<0.001). Serum sodium levels significantly declined in the intervention group (p<0.001) but not in the control group (p=0.07). There were no significant differences in potassium (p=0.89), hematocrit (p=0.23), systolic blood pressure (p=0.21) and diastolic blood pressure (p=0.97). However, urine-specific gravity had an increasing pattern in the intervention group (p<0.001) and a decreasing pattern in the control group (p<0.001). This study showed that Desmopressin inhalation could increase the AFI and urine specific gravity, enhancing oligohydramnios treatment in pregnant women, compared to serum administration.

Placental ion channels: potential target of chemical exposure

The placenta is an important organ for the exchange of substances between the fetus and the mother, hormone secretion, and fetoplacental immunological defense. Placenta has an organ-specific distribution of ion channels and trophoblasts, and placental vessels express a large number of ion channels. Several placental housekeeping activities and pregnancy complications are at least partly controlled by ion channels, which are playing an important role in regulating hormone secretion, trophoblastic homeostasis, ion transport, and vasomotor activity. The function of several placental ion channels (Na, Ca, and Cl ion channels, cation channel, nicotinic acetylcholine receptors, and aquaporin-1) is known to be influenced by chemical exposure, i.e., their responses to different chemicals have been tested and confirmed in experimental models. Here, we review the possibility that placental ion channels are targets of toxicological concern in terms of placental function, fetal growth, and development.

Prevalence and associated factors of oligohydramnios in pregnancies beyond 36 weeks of gestation at a tertiary hospital in southwestern Uganda

BACKGROUND

Oligohydramnios is associated with poor maternal and perinatal outcomes. In low-resource countries, including Uganda, oligohydramnios is under-detected due to the scarcity of ultrasonographic services. We determined the prevalence and associated factors of oligohydramnios among women with pregnancies beyond 36 weeks of gestation at Mbarara Regional Referral Hospital (MRRH) in Southwestern Uganda.

METHODS

We conducted a hospital-based cross-sectional study from November 2019 to March 2020. Included were women at gestational age > 36 weeks. Excluded were women with ruptured membranes, those in active labour, and those with multiple pregnancies. An interviewer-administered structured questionnaire was used to capture demographic, obstetric, and clinical characteristics of the study participants. We determined oligohydramnios using an amniotic fluid index (AFI) obtained using an ultrasound scan. Oligohydramnios was diagnosed in participants with AFI ≤ 5 cm. We performed multivariable logistic regression to determine factors associated with oligohydramnios.

RESULTS

We enrolled 426 women with a mean age of 27 (SD ± 5.3) years. Of the 426 participants, 40 had oligohydramnios, for a prevalence of 9.4% (95%CI: 6.8-12.6%). Factors found to be significantly associated with oligohydramnios were history of malaria in pregnancy (aOR = 4.6; 95%CI: 1.5-14, P = 0.008), primegravidity (aOR = 3.7; 95%CI: 1.6-6.7, P = 0.002) and increasing gestational age; compared to women at 37-39 weeks, those at 40-41 weeks (aOR = 2.5; 95%CI: 1.1-5.6, P = 0.022), and those at > 41 weeks (aOR = 6.0; 95%CI: 2.3-16, P = 0.001) were more likely to have oligohydramnios.

CONCLUSION

Oligohydramnios was detected in approximately one out of every ten women seeking care at MRRH, and it was more common among primigravidae, those with a history of malaria in pregnancy, and those with post-term pregnancies. We recommend increased surveillance for oligohydramnios in the third trimester, especially among prime gravidas, those with history of malaria in pregnancy, and those with post-term pregnancies, in order to enable prompt detection of this complication and plan timely interventions. Future longitudinal studies are needed to assess clinical outcomes in women with oligohydramnios in our setting.

Tanshinone IIA increased amniotic fluid volume through down-regulating placental AQPs expression via inhibiting the activity of GSK-3β

The mechanism of idiopathic oligohydramnios is still uncertain, and there is no effective and targeted treatment for it. Placental aquaporins (AQPs) were associated with idiopathic oligohydramnios. This study aimed to investigate the effect of tanshinone IIA on amniotic fluid volume (AFV) and its underlying molecular mechanisms related to placental AQPs (AQP1, AQP3, AQP8, AQP9). Results showed that compared with the women with normal AFV, placental AQP1, AQP3, AQP8, and AQP9 protein expressions were decreased in women with idiopathic oligohydramnios. Immunohistochemistry revealed localization of AQP1, AQP3, AQP8, and AQP9 mainly in trophoblast cells within labyrinth zone of mouse placenta. Also, AQP1 was located in fetal vascular endothelial cells. Pregnant mice were administered with tanshinone IIA (10 mg/kg or 50 mg/kg, n = 8, respectively) or vehicle (n = 8) from 9.5 to 18.5 gestational day (GD). Tanshinone IIA markedly increased the AFV in pregnant mice, without the effects on embryo numbers per litter, atrophic embryo rate, fetal weight, and placental weight, as well as increased the expressions of AQPs and inhibited the activity of GSK-3β in mice placenta. In JEG-3 cells, tanshinone IIA downregulated AQP1, AQP3, AQP8, AQP9 expressions and inhibited the activity of GSK-3β. Activating GSK-3β with MK-2206 eliminated these alterations. Thus, tanshinone IIA could increase AFV in pregnant mice, possibly through downregulating placental AQP1, AQP3, AQP8, and AQP9 expression via inhibiting the activity of GSK-3β. Tanshinone IIA may be optional for the treatment of idiopathic oligohydramnios.

Contribution of aquaporins in the transamniotic water flux

We explored the contribution of each aquaporin (AQP) expressed in human amnion in the transcellular water flux across the human amnion. Human amnion was placed between two lucite chambers and net water transport (Jw) was recorded by applying a hydrostatic (7 cm H₂O) and an osmotic (40 mOsm PEG 8000) pressure gradients. The hydrostatic (Phydr) and osmotic (POsm) permeabilities were calculated before and after the blocking of AQPs. Phdr showed no significant difference after the blocking of AQPs, while POsm was dramatically reduced. Interestingly, we also found that the blocking of AQP1 produced the highest decrease of POsm (80 ± 1%). Our results strongly suggested that AQP1 seems to contribute more to the maintenance of AF volume homeostasis.

Correlation of amniotic fluid index and placental aquaporin 1 levels in terms of preeclampsia

INTRODUCTION

Aquaporin 1 (AQP1) plays an important role in regulation of maternal-fetal fluid exchange and amniotic fluid volume. This present study aimed to determine the relationship between amniotic fluid index and placental AQP1 levels in terms of preeclampsia, and to reveal possible pathophysiological changes of AQP1 expression under preeclamptic conditions.

METHODS

Placental tissues and medical records information were obtained from 389 preeclamptic and 447 uncomplicated pregnancies. Placental AQP1 levels were analyzed by molecular biological methods, DNA methylation within gene promotor was determined by targeted bisulfite sequencing assay.

RESULTS

Here, we found that preeclamptic pregnancy had a greater frequency of oligohydramnios, and higher placental AQP1 levels. There was a significantly inverse correlation between amniotic fluid index and placental AQP1 levels in preeclampsia cases. Additionally, the increased AQP1 was correlated with a decreased DNA methylation within its gene promoter.

DISCUSSION

Overall, this was the first description that a greater frequency of oligohydramnios in preeclampsia was strongly associated with reprogrammed AQP1 expression via a DNA methylation-mediated epigenetic mechanism. This study suggested AQP1 might play an important role in regulating maternal-fetal fluid balance under preeclamptic conditions, providing new information for further understanding the pathophysiological mechanism of oligohydramnios in preeclampsia.

Nutritional and Physiological Regulation of Water Transport in the Conceptus

Water transport during pregnancy is essential for maintaining normal growth and development of conceptuses (embryo/fetus and associated membranes). Aquaporins (AQPs) are a family of small integral plasma membrane proteins that primarily transport water across the plasma membrane. At least 11 isoforms of AQPs (AQPs 1-9, 11, and 12) are differentially expressed in the mammalian placenta (amnion, allantois, and chorion), and organs (kidney, lung, brain, heart, and skin) of embryos/fetuses during prenatal development. Available evidence suggests that the presence of AQPs in the conceptus mediates water movement across the placenta to support the placentation, the homeostasis of amniotic and allantoic fluid volumes, as well as embryonic and fetal survival, growth and development. Abundances of AQPs in the conceptus can be modulated by nutritional status and physiological factors affecting the pregnant female. Here, we summarize the effects of maternal dietary factors (such as intakes of protein, arginine, lipids, all-trans retinoic acid, copper, zinc, and mercury) on the expression of AQPs in the conceptus. We also discuss the physiological changes in hormones (e.g., progesterone and estrogen), oxygen supply, nitric oxide, pH, and osmotic pressure associated with the regulation of fluid exchange between mother and fetus. These findings may help to improve the survival, growth, and development of embryo/fetus in livestock species and other mammals (including humans).

Pregnancy complicated by central diabetes insipidus and oligohydramnios

This is the fourth reported case of central diabetes insipidus with oligohydramnios. Central diabetes insipidus does not adversely affect pregnancy; it can present with oligohydramnios, which can be improved by treating central diabetes insipidus.

Amniotic Aaquaporins (AQP) in Normal and Pathological Pregnancies: Interest in Polyhydramnios

Polyhydramnios is a common feature diagnosed by ultrasound in the second half of pregnancy. Biochemical analysis of amniotic fluid can be useful when suspecting Bartter syndrome or digestive atresia but in most of cases, no etiology of polyhydramnios is found because of the complex regulation of amniotic fluid. Aquaporins (AQP) are transmembrane channel proteins contributing to water transfers. Some of them are expressed in fetal membranes and placenta. Their expression has been shown to be disrupted in some pathological conditions such as maternal diabetes, often associated with polyhydramnios. AQP-1, 3 and 8 levels in amniotic fluid were retrospectively measured in patients suffering from polyhydramnios (n=21) from 23 weeks of gestation (WG). They were compared to the levels observed in control subjects (n=96) and their relationship with maternal factors and neonatal issues was analyzed. AQP-1, 3, 8 levels were physiologically fluctuating, AQP-1 levels always being the lowest and AQP-3 the highest, with a significant decrease at the end of pregnancy. AQPs/AFP ratios increased about 8 folds during pregnancy, their kinetic profiles reflecting physiological dynamic evolution of amniotic fluid volume. In polyhydramnios, AQP-3 level tended to be decreased whereas AQP-8 level was decreased from mid-gestation whatever the etiology of polyhydramnios. No significant relationship was found between AQPs levels and either the fetal prematurity degree or macrosomia. No specific pattern was observed in idiopathic polyhydramnios, limiting the interest of AQPs dosage in amniotic fluid in the management of those complicated pregnancies.

Dietary L-arginine supplementation during days 14-25 of gestation enhances aquaporin expression in the placentae and endometria of gestating gilts

This study tested the hypothesis that dietary L-arginine (Arg) supplementation to pregnant gilts enhanced the expression of water channel proteins [aquaporins (AQPs)] in their placentae and endometria. Gilts were fed twice daily 1 kg of a corn and soybean meal-based diet supplemented with 0.0%, 0.4%, or 0.8% Arg between Days 14 and 25 of gestation. On Days 25 and 60 of gestation, gilts were hysterectomized to obtain placentae and endometria. On Day 25 of gestation, supplementation with 0.4% Arg increased (P < 0.05) the abundance of placental AQP9 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) placental AQP1 and AQP9 proteins, compared with controls. On Day 60 of gestation, supplementation with 0.4% Arg increased (P < 0.05) endometrial AQP1 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) endometrial AQP5 and AQP9 proteins. Supplementation with 0.8% Arg increased the endometrial expression of AQP1, AQP5, and AQP9 proteins located in the luminal epithelium and glandular epithelium of endometria, and placental transport of ³H₂O. Collectively, these results indicate that dietary Arg supplementation stimulates the expression of selective AQPs in porcine placenta and endometria, thereby enhancing water transport from mother to fetus and expanding the chorioallantoic membranes during the period of placentation.

Hourly fetal urine production rate in isolated oligohydramnios at term

OBJECTIVE

The aim of this study was to evaluate the hourly fetal urine production rate (HFUPR) via three-dimensional ultrasonography in women with isolated oligohydramnios and compare with normal pregnant women at term.

MATERIALS AND METHODS

This was a prospective observational cohort study of 112 women from 34 to 40 6/7 weeks' gestation. They were classified into three groups according to the amniotic fluid index (AFI) and ultrasonographic estimated fetal weight (EFW) as isolated oligohydramnios (defined as AFI below 5% and appropriate EFW corresponding to gestational age) (n = 34) and IUGR (defined as EFW below 5% corresponding to gestational age irrespective amniotic fluid) (n = 17), and normal pregnancy (n = 61). HFUPR was measured using three-dimensional virtual organ computer-aided analysis. Adverse perinatal outcomes in all participants were examined.

RESULTS

There was no significant difference in HFUPR between patients with isolated oligohydramnios and women with normal pregnancies (median, 40.0 mL/h [interquartile range [IQR] 31.0-66.5] vs. 48.6 [31.5-81.2], p = 0.224). HFUPR was significantly decreased in the IUGR group (13.8 mL/h [IQR 10.1-24.8]), compared to the normal pregnancy group (p<0.001) and the isolated oligohydramnios group (p<0.001). HFUPR was significantly decreased in neonates with adverse perinatal outcomes compared to the control (24.7 mL/h [IQR 13.4-47.4] vs. 43.6 [29.8-79.0], p = 0.016).

CONCLUSION

HFUPR was not decreased in patients with isolated oligohydramnios but was decreased in patients with IUGR when compared to normal controls at term.

The Relevance of Aquaporins for the Physiology, Pathology, and Aging of the Female Reproductive System in Mammals

Aquaporins constitute a group of water channel proteins located in numerous cell types. These are pore-forming transmembrane proteins, which mediate the specific passage of water molecules through membranes. It is well-known that water homeostasis plays a crucial role in different reproductive processes, e.g., oocyte transport, hormonal secretion, completion of successful fertilization, blastocyst formation, pregnancy, and birth. Further, aquaporins are involved in the process of spermatogenesis, and they have been reported to be involved during the storage of spermatozoa. It is noteworthy that aquaporins are relevant for the physiological function of specific parts in the female reproductive system, which will be presented in detail in the first section of this review. Moreover, they are relevant in different pathologies in the female reproductive system. The contribution of aquaporins in selected reproductive disorders and aging will be summarized in the second section of this review, followed by a section dedicated to aquaporin-related proteins. Since the relevance of aquaporins for the male reproductive system has been reviewed several times in the recent past, this review aims to provide an update on the distribution and impact of aquaporins only in the female reproductive system. Therefore, this paper seeks to determine the physiological and patho-physiological relevance of aquaporins on female reproduction, and female reproductive aging.

Expression and Regulation of Aquaporins in Pregnancy Complications and Reproductive Dysfunctions

Aquaporins (AQPs), small hydrophobic integral membrane proteins, mediate rapid transport of water and small solutes. The abnormal expressions of AQPs are associated with pregnancy complications and reproductive dysfunctions, including preeclampsia, gestational diabetes mellitus, tubal ectopic pregnancy, intrahepatic cholestasis of pregnancy, preterm birth, chorioamnionitis, polyhydramnios, and oligohydramnios, thus resulting in adverse pregnancy outcomes. This review explains the alterations of AQPs in pregnancy complications and reproductive dysfunctions and summarizes the molecular mechanisms involved in the regulations of AQPs by drugs such as oxytocin, polychlorinated biphenyls, all-trans-retinoic acid, salvia miltiorrhiza, and insulin, or other factors such as oxygen and osmotic pressure. All the research provides evidence that AQPs could be the new therapeutic targets of pregnancy-related diseases.

Prenatal exposure to isolated amniotic fluid disorders and the risk for long-term cardiovascular morbidity in the offspring

Amniotic fluid (AF) abnormalities are often associated with short-term adverse pregnancy outcomes, including cardiovascular-related. We sought to assess whether in utero exposure to AF abnormalities increases the risk for long-term cardiovascular morbidity of the offspring. We examined the incidence of cardiovascular disorders in singletons exposed and non-exposed to isolated oligohydramnios or polyhydramnios. Cardiovascular morbidity was assessed up to the age of 18 years according to a predefined set of ICD-9 codes. A Kaplan-Meier survival curves were used to compare cumulative morbidity incidence. A Cox proportional hazards model was constructed to control for confounders. During the study period, 195,943 newborns met the inclusion criteria, of which 2.0% (n = 4063) were in pregnancies diagnosed with isolated oligohydramnios and 2.9% (n = 5684) in pregnancies with isolated polyhydramnios. Children exposed to isolated AF disorders had significantly higher rates of long-term cardiovascular morbidity (p=.042). Children exposed to isolated oligohydramnios had higher cumulative incidence of cardiovascular morbidity (log-rank test p=.026) compared to unexposed children, opposing to what was demonstrate when comparing polyhydramnios vs. normal AFV (log-rank test p=.749). In the Cox regression model, while controlling for confounders, isolated oligohydramnios were found to be independently associated with long-term cardiovascular morbidity of the offspring.

LncRNA and transcriptomic analysis of fetal membrane reveal potential targets involved in oligohydramnios

Background

The multiple causes of oligohydramnios make it challenging to study. Long noncoding RNAs (lncRNAs) are sets of RNAs that have been proven to function in multiple biological processes. The purpose of this study is to study expression level and possible role of lncRNAs in oligohydramnios.

Methods

In this study, total RNA was isolated from fetal membranes resected from oligohydramnios pregnant women (OP) and normal amount of amniotic fluid pregnant women (Normal). LncRNA microarray was used to analyze the differentially expressed lncRNAs and mRNAs. Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to analyze the main enrichment pathways of differentially expressed mRNAs. Real-time quantitative PCR (qPCR) was used to validate the lncRNA expression level.

Results

LncRNA microarray analysis revealed that a total of 801 lncRNAs and 367 mRNAs were differentially expressed in OP; in these results, 638 lncRNAs and 189 mRNAs were upregulated, and 163 lncRNAs and 178 mRNAs were downregulated. Of the lncRNAs, 566 were intergenic lncRNAs, 351 were intronic antisense lncRNAs, and 300 were natural antisense lncRNAs. The differentially expressed lncRNAs were primarily located in chromosomes 2, 1, and 11. KEGG enrichment pathways revealed that the differentially expressed mRNAs were enriched in focal adhesion as well as in the signaling pathways of Ras, tumor necrosis factor (TNF), estrogen, and chemokine. The qPCR results confirmed that LINC00515 and RP11-388P9.2 were upregulated in OP. Furthermore, the constructed lncRNA–miRNA–mRNA regulatory network revealed tenascin R (TNR), cystic fibrosis transmembrane conductance regulator (CFTR), ATP-binding cassette sub-family A member 12 (ABCA12), and collagen 9A2 (COL9A2) as the candidate targets of LINC00515 and RP11-388P9.2.

Conclusions

In summary, we revealed the profiles of lncRNA and mRNA in OP. These results might offer potential targets for biological prevention for pregnant women with oligohydramnios detected before delivery and provided a reliable basis for clinical biological treatment in OP.

Prenatal exposure to isolated amniotic fluid disorders and the risk for long-term endocrine morbidity of the offspring

BACKGROUND

Amniotic fluid abnormalities may be associated with adverse perinatal outcomes, some of which are endocrine related.

OBJECTIVE

To evaluate whether in utero exposure to amniotic fluid abnormalities is associated with long-term endocrine morbidity in the offspring.

STUDY DESIGN

In this cohort study, the incidence of long-term endocrine disorders was compared between singletons exposed and non-exposed to oligohydramnios or polyhydramnios.

RESULTS

During the study period, 195 943 newborns were included in the study, of them 2.0% (n = 4072) and 2.9% (n = 5684) were exposed to oligohydramnios and polyhydramnios, respectively. Long-term endocrine morbidity was higher among children exposed to isolated amniotic fluid disorders, as was also noted in the Kaplan-Meier survival curve (log-rank test p < 0.001). Abnormal amniotic fluid volume was found to be independently associated with long-term endocrine morbidity of the offspring according to a Cox regression model controlled for clinically related confounders.

CONCLUSION

In utero exposure to isolated amniotic fluid abnormalities is independently associated with long-term endocrine morbidity in the offspring.

Aquaporin 1 affects pregnancy outcome and regulates aquaporin 8 and 9 expressions in the placenta

To explore the effects of aquaporin (AQP) 1 on pregnancy outcome and the association between expression of AQP1 and other AQPs in the placenta and foetal membranes, the rate of copulatory plugs and pregnancy, amniotic fluid (AF) volume, osmolality and composition were determined in AQP1-knockout (AQP1^−/−) mice at different gestational days (GD). The expression and location of AQP1 and other AQPs in the placenta and foetal membranes of AQP1^−/− mice, AQP1-siRNA transfected WISH cells and oligohydramnios patients were also detected. Compared to control mice, AQP1^−/− mice exhibited reduced copulation plug and successful pregnancy rates, but these effects were accompanied by a larger AF volume and lower AF osmolality at late gestation. AQP9 expression was significantly decreased in the placenta and foetal membranes of AQP1^−/− mice, while AQP8 level was elevated in the foetal membranes of AQP1^−/− mice. Moreover, AQP9 expression was suppressed in WISH cells after AQP1 downregulation. Furthermore, AQP9 expression was associated with AQP1 level in the placenta and foetal membranes in oligohydramnios. AQP1 may play a critical role in regulating pregnancy outcome and maternal-foetal fluid homeostasis. Changes in AQP1 expression may lead to compensatory alterations in AQP8 and AQP9 expression in the placenta.

Altered proteomics profile in the amnion of patients with oligohydramnios

In pregnancy, idiopathic oligohydramnios is an obstetrical complication that compromises maternal health with poor perinatal outcome. Effective therapeutic treatment of this condition has been hampered by the unknown etiology and lack of understanding of cellular and molecular mechanisms that underlie idiopathic oligohydramnios. Amniotic fluid volume (AFV) is determined by intramembranous (IM) transport of amniotic fluid across the amnion and this pathway is regulated to maintain AFV within the normal range. To gain understanding of the causes of idiopathic oligohydramnios, we performed proteomics analysis of the human amnion to investigate the changes in protein expression profiles of cellular transport pathways and regulators in patients with oligohydramnios. Placental amnions from five patients with normal pregnancies and five patients with oligohydramnios were subjected to proteomics experiments followed by bioinformatics analysis. Using Ingenuity Pathway Analysis (IPA) software, five categories of biological functions and multiple canonical pathways within each category were revealed. The top differentially expressed proteins that participate in mediating these pathways were identified. The functional pathways activated include: (a) cellular assembly and organization, (b) cell signaling and energy metabolism, and (c) immunological, infectious, and inflammatory functions. Furthermore, the analysis identified the category of pathways that facilitate molecular endocytosis and vesicular uptake. Under oligohydramniotic conditions, the mediators of clathrin vesicle-mediated uptake and transport as well as intracellular trafficking mediators were up-regulated. These findings suggest that idiopathic oligohydramnios may be associated with alternations in cellular organization and immunological functions as well as increases in activity of vesicular transport pathways across the amnion.

Aquaporins during pregnancy

Aquaporins (AQPs) are water channels proteins that facilitate water flux across cell membranes in response to osmotic gradients. Despite of the differences in the mammalian placentas, the conserved combination of AQPs expressed in placental and fetal membranes throughout gestation suggests that these proteins may be important in the regulation of fetal water homeostasis. Thus, AQPs may regulate the amniotic fluid volume and participate in the trans-placental transfer of water. Apart from their classical roles, recent studies have revealed that placental AQPs may also cooperate in cellular processes such as the migration and the apoptosis of the trophoblasts. Aquaglyceroporins can also participate in the energy metabolism and in the urea elimination across the placenta. Many factors including oxygen, hormones, acid-basis homeostasis, maternal dietary status, interaction with other transport proteins and osmotic stress are proposed to regulate their expression and function during gestation and alterations result in pathological pregnancies.

Uterine and placental specific localization of AQP2 and AQP8 is related with changes of serum progesterone levels in pregnant queens

Aquaporins play vital roles in reproductive physiology. This study evaluates the expression and localization dynamics of AQP1, AQP2, AQP3 and AQP8 in the endometrium and placental transference zone during pregnancy in queens by means of immunohistochemistry and Western blot. Animals were distributed into six groups: non-pregnant queens with low levels of serum progesterone (P₄), non-pregnant animals with high P₄ levels, and queens at 30, 40, 50 and 60 days of pregnancy. All AQPs were present in glandular and luminal epithelia and myometrium. AQP1 was also present in the endometrial endothelia. AQP2, AQP3 and AQP8 were found in trophoblast. In endometrial samples with P₄ above 2 ng/mL, AQP2 and AQP8 were distributed across plasma membrane and cytoplasm, whereas progesterone levels under 1 ng/mL kept both AQPs confined to the plasma membrane. Western blot showed no significant changes in AQPs expression among the stages. In conclusion, our results indicate that the distribution of AQP2 and AQP8 in the queen reproductive tract is related to P₄ levels.

New Insights Into the Role of Placental Aquaporins and the Pathogenesis of Preeclampsia

Accumulated evidence suggests that an abnormal placentation and an altered expression of a variety of trophoblast transporters are associated to preeclampsia. In this regard, an abnormal expression of AQP3 and AQP9 was reported in these placentas. Recent data suggests that placental AQPs are not only water channel proteins and that may participate in relevant processes required for a normal placental development, such as cell migration and apoptosis. Recently we reported that a normal expression of AQP3 is required for the migration of extravillous trophoblast (EVT) cells. Thus, alterations in this protein might lead to an insufficient transformation of the maternal spiral arteries resulting in fluctuations of oxygen tension, a potent stimulus for oxidative damage and trophoblast apoptosis. In this context, the increase of oxygen and nitrogen reactive species could nitrate AQP9, producing the accumulation of a non-functional protein affecting the survival of the villous trophoblast (VT). This may trigger the exacerbated release of apoptotic VT fragments into maternal circulation producing the systemic endothelial dysfunction underlying the maternal syndrome. Therefore, our hypothesis is that the alteration in the expression of placental AQPs observed at the end of gestation may take place during the trophoblast stem cell differentiation, disturbing both EVT and VT cells development, or during the VT differentiation and turnover. In both situations, VT is affected and at last the maternal vascular system is activated leading to the clinical manifestations of preeclampsia.

Loss of Aquaporin-3 in Placenta and Fetal Membranes Induces Growth Restriction in Mice

Aquaporin (AQP) 3, a facilitated transporter of water and glycerol, expresses in placenta and fetal membranes, but the detailed localization and function of AQP3 in placenta remain unclear. To elucidate a role of AQP3 in placenta, we defined the expression and cellular localization of AQP3 in placenta and fetal membranes, and investigated the structural and functional differences between wild-type and AQP3 null mice. Gestational sacs were removed during mid-gestational period and amniotic fluid was aspirated for measurements of volume and composition. Fetuses with attached placenta and fetal membranes were weighed and processed for histological assessment. AQP3 strongly expressed in basolateral membrane of visceral yolk sac cells of fetal membrane, the syncytiotrophoblasts of the labyrinthine placenta and fetal nucleated red blood cell membrane. Mice lacking AQP3 did not exhibit a significant defect in differentiation of trophoblast stem cells and normal placentation. However, AQP3 null fetuses were smaller than their control litter mates in spite of a decrease in litter size. The total amniotic fluid volume per gestational sac was reduced, but the amniotic fluid-to-fetal weight ratio was increased in AQP3 null mice compared with wild-type mice. Glycerol, free fatty acid and triglyceride levels in amniotic fluid of AQP3 null mice were significantly reduced, whereas lactate level increased when compared to those of wild-type mice. These results suggest a role for AQP3 in supplying nutrients from yolk sac and maternal blood to developing fetus by facilitating transport of glycerol in addition to water, and its implication for the fetal growth in utero.

The use of mrp1-deficient (Danio rerio) zebrafish embryos to investigate the role of Mrp1 in the toxicity of cadmium chloride and benzo[a]pyrene

Previous studies in our lab have revealed that both P-glycoprotein (Pgp) and multi-resistance associated protein (Mrp) 1 played important roles in the detoxification of heavy metals and polycyclic aromatic hydrocarbon (PAH) in zebrafish embryos. This paper aims to extend this research by using mrp1-deficient model to illustrate the individual function of Mrp1. In this respect, CRISPR/Cas9 system was employed to generate a frameshift mutation in zebrafish mrp1 causing premature translational stops in Mrp1. Significant reduction on the efflux function of Mrps was found in mutant zebrafish embryos, which correlated well with the significantly enhanced accumulation and toxicity of cadmium chloride (CdCl₂) and benzo[a]pyrene (BαP), indicating the protective role of the corresponding protein. The different alteration on the accumulation and toxicity of Cd²⁺ and BαP could be attributed to the fact that Cd²⁺ and its metabolites were mainly excreted by Mrp1, while BαP was primarily pumped out by Pgp. More importantly, the compensation mechanism for the absence of Mrp1, including elevated glutathione (GSH) level and up-regulated expression of pgp and mrp2 were also found. Thus, mrp1-deficient zebrafish embryo could be a useful tool in the investigation of Mrp1 functions in the early life stages of aquatic organisms. However, compensation mechanism should be taken into consideration in the interpretation of results obtained with mrp1-deficient fish.

Aquaporins in ovine amnion: responses to altered amniotic fluid volumes and intramembranous absorption rates

Aquaporins (AQPs) are transmembrane channel proteins that facilitate rapid water movement across cell membranes. In amniotic membrane, the AQP‐facilitated transfer of water across amnion cells has been proposed as a mechanism for amniotic fluid volume (AFV) regulation. To investigate whether AQPs modulate AFV by altering intramembranous absorption (IMA) rate, we tested the hypothesis that AQP gene expression in the amnion is positively correlated with IMA rate during experimental conditions when IMA rate and AFV are modified over a wide range. The relative abundances of AQP1, AQP3, AQP8, AQP9, and AQP11 mRNA and protein were determined in the amnion of 16 late‐gestation ovine fetuses subjected to 2 days of control conditions, urine drainage, urine replacement, or intraamniotic fluid infusion. AQP mRNA levels were determined by RT‐qPCR and proteins by western immunoblot. Under control conditions, mRNA levels among the five AQPs differed more than 20‐fold. During experimental treatments, mean IMA rate in the experimental groups ranged from 100 ± 120 mL/day to 1370 ± 270 mL/day. The mRNA levels of the five AQPs did not change from control and were not correlated with IMA rates. The protein levels of AQP1 were positively correlated with IMA rates (r² = 38%, P = 0.01) while the remaining four AQPs were not. These findings demonstrate that five AQPs are differentially expressed in ovine amnion. Our study supports the hypothesis that AQP1 may play a positive role in regulating the rate of fluid transfer across the amnion, thereby participating in the dynamic regulation of AFV.

Polyhydramnios in Lrp4 knockout mice with bilateral kidney agenesis: Defects in the pathways of amniotic fluid clearance

Amniotic fluid volume during mid-to-late gestation depends mainly on the urine excretion from the foetal kidneys and partly on the fluid secretion from the foetal lungs during foetal breathing-like movements. Urine is necessary for foetal breathing-like movements, which is critical for foetal lung development. Bilateral renal agenesis and/or obstruction of the urinary tract lead to oligohydramnios, which causes infant death within a short period after birth due to pulmonary hypoplasia. Lrp4, which functions as an agrin receptor, is essential for the formation of neuromuscular junctions. Herein, we report novel phenotypes of Lrp4 knockout (Lrp4(-/-)) mice. Most Lrp4(-/-) foetuses showed unilateral or bilateral kidney agenesis, and Lrp4 knockout resulted in polyhydramnios. The loss of Lrp4 compromised foetal swallowing and breathing-like movements and downregulated the expression of aquaporin-9 in the foetal membrane and aquaporin-1 in the placenta, which possibly affected the amniotic fluid clearance. These results suggest that amniotic fluid removal was compromised in Lrp4(-/-) foetuses, resulting in polyhydramnios despite the impairment of urine production. Our findings indicate that amniotic fluid removal plays an essential role in regulating the amniotic fluid volume.

Differential expression and regional distribution of aquaporins in amnion of normal and gestational diabetic pregnancies

The region of the amnion overlying the placenta plays an active role in fluid exchange between amniotic fluid and fetal blood perfusing the surface of the placenta, whereas little transfer occurs across the reflected amnion that contacts the membranous chorion. Because aquaporins (AQPs) facilitate rapid movement of water across cells, we hypothesized that AQP gene expression in placental amnion is higher than in reflected amnion. Furthermore, because gestational diabetes mellitus (GDM) is often associated with polyhydramnios, we hypothesized that amnion AQP gene expression is reduced when amniotic fluid volume is elevated. Human placental and reflected amnion were obtained at cesarean delivery and subjected to relative quantitation of AQP mRNA by real-time RT-qPCR and proteins by western immunoblot. Amnion mRNA levels of five AQPs differed by up to 400-fold (P < 0.001), with AQP1 and AQP3 most abundant, AQP8 least and AQP9 and AQP11 intermediately expressed. Aquaporin proteins showed a similar profile. Aquaporin mRNA abundance was higher (P < 0.001) in placental than reflected amnion, whereas protein levels were lower (P < 0.01). In GDM pregnancies, neither AQP mRNA nor protein levels were different from normal. There was no correlation between AQP mRNA or protein levels with the amniotic fluid index in normal or GDM subjects. We conclude that there is a strong differential expression profile among individual AQPs and between regions of the amnion. These findings suggest differences in contribution of individual AQPs to water transport in the two regions of the amnion. Furthermore, AQP expression in the amnion is not altered in patients with GDM.

Progesterone, estradiol, arachidonic acid, oxytocin, forskolin and cAMP influence on aquaporin 1 and 5 expression in porcine uterine explants during the mid-luteal phase of the estrous cycle and luteolysis: an in vitro study

BACKGROUND

The cell membrane water channel protein, aquaporins (AQPs), regulate cellular water transport and cell volume and play a key role in water homeostasis. Recently, AQPs are considered as important players in the field of reproduction. In previous studies, we have established the presence of AQP1 and 5 in porcine uterus. Their expression at protein level altered in distinct tissues of the female reproductive system depending on the phase of the estrous cycle. However, the regulation of aquaporin genes and proteins expression has not been examined in porcine uterine tissue. Therefore, we have designed an in vitro experiment to explain whether steroid hormones, progesterone (P4) and estradiol (E2), and other factors: oxytocine (OT), arachidonic acid (AA; substrate for prostaglandins synthesis) as well as forskolin (FSK; adenylate cyclase activator) and cAMP (second messenger, cyclic adenosine monophosphate) may impact AQPs expression.

METHODS

Uterine tissues were collected on Days 10-12 and 14-16 of the estrous cycle representing the mid-luteal phase and luteolysis. Real-time PCR and Western blot analysis were performed to examine the expression of porcine AQP1 and AQP5. Their expression in the uterine explants was also evaluated by immunohistochemistry.

RESULTS

The results indicated that uterine expression of AQP1 and AQP5 potentially remains under control of steroid hormones and AA-derived compounds (e.g. prostaglandins). P4, E2, AA, FSK and cAMP cause translocation of AQP5 from apical to the basolateral plasma membrane of the epithelial cells, which might affect the transcellular water movement (through epithelial cells) between uterine lumen and blood vessels. The AC/cAMP pathway is involved in the intracellular signals transduction connected with the regulation of AQPs expression in the pig uterus.

CONCLUSIONS

This study documented specific patterns of AQP1 and AQP5 expression in response to P4, E2, AA, FSK and cAMP, thereby providing new indirect evidence of their role in maintaining the local fluid balance within the uterus during the mid-luteal phase of the estrous cycle and luteolysis in pigs.

Expression of aquaporins early in human pregnancy

BACKGROUND

Aquaporins (AQPs) constitute a family of channel proteins implicated in transmembrane water transport. Thirteen different AQPs (AQP0-12) have been described but their precise biologic function still remains unclear. AQPs 1, 3, 4, 8, and 9 expression has been described in human chorion, amnion and placenta; however, AQP4 is the only that has been identified in the first trimester of human pregnancy.

OBJECTIVE

To assess multiplicity of AQPs expression from 10th to 14th week gestation.

POPULATION AND METHODS

Chorionic villi samples (CVS) collected in pregnant women for prenatal diagnosis were analysed by real time-PCR to assess cDNA expression of AQPs 1, 2, 3, 4, 5, 6, 7, 8, 9, and 11, and compared with AQPs expression in placentas from normal term pregnancies.

RESULTS

26 CVS corresponding to 26 pregnant women (age: 32.7±4.5 years; gestational age: 12.4±0.9 weeks) and 10 placental samples corresponding to normal term pregnancies were analysed. In CVS karyotype was normal in 16 cases, trisomy in 6 cases, mosaicism in 1 and unknown in 1. We found high mRNA expression for AQPs 1, 3, 9 and 11, low for AQPs 4, 5, and 8, and non-detectable for AQPs 2, 6, and 7 in chorionic villi.

CONCLUSIONS

This is the first study systematically assessing the expression of a multiplicity of AQPs in chorionic villi samples between 10th and 14th weeks of gestation. High expression of AQP11 has been identified for the first time in early stages of human pregnancy. Chromosomal abnormalities did not alter AQPs' expression.

Expression of aquaporin water channels in canine fetal adnexa in respect to the regulation of amniotic fluid production and absorption

Amniotic fluid (AF) is created by the flow of fluid from the fetal lung and bladder and reabsorbed in part by fetal swallowing and partly by the transfer across the amnion to the fetal circulation. Placental water flux is an important factor in determining AF volume and fetal hydration. In addition the fetal membranes might be involved in the regulation of fluid composition. To understand the mechanisms responsible for maintaining a correct balance of AF volume we evaluated the expression of aquaporins (AQPs) in canine fetal adnexa. AQPs are a family of integral membrane proteins permitting passive but physiologically rapid transcellular water movement. The presence of AQP1, 3, 5, 8 and -9 was immunohistochemically assessed in canine fetal adnexa, collected in early, middle and late-gestation during ovario-hysterectomies performed with fully informed owners' consent. Changes in AF volume and biochemical composition were also evaluated throughout pregnancy. Our results show distinct aquaporin expression patterns in maternal and extraembryonic tissues in relation to pregnancy period. AQP1 was localized in placental endothelia, allantochorion, amnion, allantois and yolk sac. AQP3 was present in the placental labyrinth, amnion, allantois and yolk sac. AQP8 was especially evident on the epithelia lining the glandular chambers, the amniotic and allantois sacs. AQP9, a channel highly permeable to water and urea, was observed in epithelia of amnion, allantois and yolk sac. In summary, AQP1, 3, 5, 8 and -9 have distinct expression patterns in canine fetal membranes and placenta in relation to pregnancy period, suggesting an involvement in mediating the AF changes during gestation.

Maternal-fetal fluid balance and aquaporins: from molecule to physiology

Maternal-fetal fluid balance is critical during pregnancy, and amniotic fluid is essential for fetal growth and development. The placenta plays a key role in a successful pregnancy as the interface between the mother and her fetus. Aquaporins (AQPs) form specific water channels that allow the rapid transcellular movement of water in response to osmotic/hydrostatic pressure gradients. AQPs expression in the placenta and fetal membranes may play important roles in the maternal-fetal fluid balance.

Progesterone maintains amniotic tight junctions during midpregnancy in mice

The amniotic epithelium is in direct contact with the amniotic fluid and restricts fluid flux via the paracellular pathway by means of tight junctions (TJs). Several factors affect TJs to modulate the paracellular flux. Progesterone contributes to the antenatal formation and disappearance of TJs in uterine and mammary epithelial tissues. In this study, we investigated whether progesterone positively or negatively influences amniotic TJs. The administration of RU-486, a progesterone receptor (PR) antagonist, into pregnant mice adversely affects the localization and expression of claudin-3 and claudin-4 in the amniotic epithelium. RU-486 administration also increased the permeability of the amniotic membrane. In organ-cultured amniotic membranes, progesterone induced increases in claudin-3 and claudin-4 expression in a dose-dependent manner but did not influence their localization. PRs were also present in the amniotic epithelium during midpregnancy but they disappeared during late pregnancy. These results indicate that the progesterone/PR pathway maintains TJs in the amniotic epithelium during midpregnancy.

Review: Water channel proteins in the human placenta and fetal membranes

It has been established that the permeability of the human placenta increases with advancing gestation. Indirect evidence has also proposed that aquaporins (AQPs) may be involved in the regulation of placental water flow but the mechanisms are poorly understood. Five AQPs have been found in the human placenta and fetal membranes [AQP1, 3, 4, 8 and 9]. However, the physiological function(s) and the regulation of these proteins remain unknown. Emerging evidence has shown that human fetal membrane AQPs may have a role in intramembranous amniotic fluid water regulation and that alterations in their expression are related to polyhydramnios and oligohydramnios. In addition, we have observed a high expression of AQP3 and AQP9 in the apical membrane of the syncytiotrophoblast. Moreover, AQP9 was found to be increased in preeclamptic placentas, but it could not be related to its functionality for the transport of water and mannitol. However, a significant urea flux was seen. Since preeclampsia is not known to be associated with an altered water flux to the fetus we propose that AQP9 might not have a key role in water transport in human placenta, but a function in the energy metabolism or the urea uptake and elimination across the placenta. However, the role of AQP9 in human placenta is still speculative and needs further studies. Insulin, hCG, cAMP and CFTR have been found to be involved in the regulation of the molecular and functional expression of AQPs. Further insights into these mechanisms may clarify how water moves between the mother and the fetus.

Early compensatory adaptations in maternal undernourished pregnancies in rats: role of the aquaporins

OBJECTIVE

To investigate the effect of maternal undernutrition (MUN) during pregnancy on fetal and placental weight, amniotic fluid (AF) volume, AF osmolality and ion concentrations at gestational ages E16 and E20. We also quantified protein expression of water channels (aquaporins; AQPs).

METHODS

Pregnant rat dams were fed an ad libitum diet (AdLib; n = 6) or were 50% MUN (n = 6) beginning at E10 of gestation. At E16 and E20, we assessed the effect of MUN on fetal and placental weights, AF volume and osmolality, and placental expression of AQP1, 8 and 9. We focused on two uterine positions (proximal and mid-horns) with the extremes of nutrient/oxygen supply. We also separately studied the basal zone (hormone production) and the labyrinth zone (feto-maternal exchange).

RESULTS

We showed that at E16, MUN fetal, and placental weights were unchanged and that, similarly, MUN AF volume, osmolality were comparable to AdLib. At E20, however, MUN fetal and placental zonal weights were significantly decreased. Inversely, due to MUN, maternal and fetal plasma osmolality and Na+ concentrations were significantly increased. Further, MUN AF volume was significantly reduced, while AF osmolality and Na+ concentration were increased at E20.

CONCLUSION

Placental basal zone showed variable changes in AQP expression unrelated to position in the uterus or the gestational age (and thus severity of the fetal/placental growth restriction). In the labyrinth zone, MUN placental AQP1 was significantly decreased, whereas AQP8 and 9 expressions were significantly increased at E16 and E20. Dysregulation of AQPs' expression prior to the occurrence of oligohydramnios may represent a compensatory mechanism under conditions of early MUN.

The expression of aquaporin 8 and aquaporin 9 in fetal membranes and placenta in term pregnancies complicated by idiopathic polyhydramnios

BACKGROUND

Aquaporins are a family of membrane-bound water channel proteins that regulate the flow of water across a variety of biological membranes. The expression of aquaporin 8 and aquaporin 9 has been demonstrated in human chorioamniotic membrane and placenta. But their roles in the pathophysiology of polyhydramnios are unclear.

AIMS

To study the expression of aquaporin 8 and aquaporin 9 in fetal membranes and placenta in term pregnancies complicated by idiopathic polyhydramnios and to explore the association between aquaporin expressions and polyhydramnios.

SUBJECTS

The placentas were collected from 51 patients who underwent elective Cesarean sections at term, of which 21 cases had idiopathic polyhydramnios and the other 30 had normal amniotic fluid volume.

OUTCOME MEASURES

Real-time polymerase chain reaction and immunohistochemistry techniques were used to determine the expression and localization of aquaporin 8 and aquaporin 9 in the amnion, chorion and placenta.

RESULTS

Expression of aquaporin 8 and aquaporin 9 was detected in the amnion, chorion and placenta and located in amnion epithelia, chorion cytotrophoblasts and placental trophoblast. Compared to normal amniotic fluid volume group, the expression of aquaporin 8 in amnion, and aquaporin 9 in amnion and chorion, were significantly increased in idiopathic polyhydramnios group; however, their expression in the placenta was significantly decreased.

CONCLUSIONS

When polyhydramnios occurs, expression of aquaporin 8 and aquaporin 9 in fetal membranes and placenta is an adaptive change, which may be involved in the regulation of amniotic fluid volume. However, the modulation factors of the aquaporin 8 and aquaporin 9 expressions need further study.

Altered global gene expressions of human placentae subjected to assisted reproductive technology treatments

BACKGROUND

Researchers are more and more concerning the safety of fetus or offspring derived from assisted reproductive technology (ART) treatment. As the placenta is a critical organ that sustains and protects the fetus, we hypothesize that altered global gene expression of the placenta subjected to ART manipulation may reflect changes associated with ART procedures and subsequently causal related to offspring health.

METHODS

Three term placenta samples were obtained from patients undergone in vitro fertilization and embryo transfer due to oviductal factors only. Other three control placentae were from those underwent normal pregnancy. A GeneChip Affymetrix HG-U133 Plus 2.0 Array was utilized to analyze the genes. Using qRT-PCR we certified microarray data from 10 dysregulated genes. Five genes were localized precisely in the placenta as per immunohistochemistry.

RESULTS

Twenty-six differentially expressed genes were identified in the ART-treated placentae: 17 up-regulated; 9 down-regulated. Eighteen of these were classified into six groups according to critical placental function: immune response; transmembrane transport; metabolism; oxidative stress; cell differentiation; and other functions. Genes involved in immune response, such as ERAP2 and STAT4, and those regulating cell differentiations, such as MUC1, were discerned to be differentially expressed. These gene products were expressed in the placental villus tissues, either in the cytoplasm or in the membrane of syncytiotrophoblastic cells.

CONCLUSION

To our knowledge, this is the first study in comparing differentially expressed genes in placentae from patients undergone ART treatment vs. those underwent normal pregnancy. Abnormal profiles of critical placental functioning genes, such as ERAP2, STAT4 and MUC1, may be valuable biomarkers to understand how the placenta affects fetal development and ART-derived offspring's health problems.