Guinea Pig Placenta Research Articles

Nanoparticle-mediated transgene expression of insulin-like growth factor 1 in the growth restricted guinea pig placenta increases placenta nutrient transporter expression and fetal glucose concentrations.

Fetal growth restriction (FGR) significantly contributes to neonatal and perinatal morbidity and mortality. Currently, there are no effective treatment options for FGR during pregnancy. We have developed a nanoparticle gene therapy targeting the placenta to increase expression of human insulin-like growth factor 1 (hIGF1) to correct fetal growth trajectories. Using the maternal nutrient restriction guinea pig model of FGR, an ultrasound-guided, intraplacental injection of nonviral, polymer-based hIGF1 nanoparticle containing plasmid with the hIGF1 gene and placenta-specific Cyp19a1 promotor was administered at mid-pregnancy. Sustained hIGF1 expression was confirmed in the placenta 5 days after treatment. Whilst increased hIGF1 did not change fetal weight, circulating fetal glucose concentration were 33%-67% higher. This was associated with increased expression of glucose and amino acid transporters in the placenta. Additionally, hIGF1 nanoparticle treatment increased the fetal capillary volume density in the placenta, and reduced interhaemal distance between maternal and fetal circulation. Overall, our findings, that trophoblast-specific increased expression of hIGF1 results in changes to glucose transporter expression and increases fetal glucose concentrations within a short time period, highlights the translational potential this treatment could have in correcting impaired placental nutrient transport in human pregnancies complicated by FGR.

Sex-Selective Increase of IGF-2 Expression in the Hypoxic Guinea Pig Placenta of Growth-Restricted Fetuses.

Chronic hypoxia can cause fetal growth restriction (FGR) through placental dysfunction. Insulin-like growth factors (IGFs), such as IGF-2, play a major role in preservation of placental growth and function. We investigated the effects of chronic hypoxia and sex on protein expression of the IGF-2 pathway in placentas selected from asymmetric-FGR fetuses. Time-mated pregnant guinea pigs were assigned to normoxia (NMX, 21% O2) or hypoxia (HPX, 10.5% O2) during the last 14days of pregnancy. Placentas were selected from male and female symmetrically grown NMX fetuses (fetal wt between 25th ile-75th ile) and HPX fetuses of asymmetric-FGR (fetal wt < 25th ile and brain:liver wt > 50th ile). Effects of HPX and sex on placenta protein expression of the IGF-2 signaling proteins (IGF-2, PI3K, AKT-P, total AKT, PCNA, a cell proliferation marker) were evaluated by immunoblotting. Effects of HPX and sex on morphometric parameters were analyzed using two-way ANOVA (p < 0.05). HPX reduced (p < 0.005) fetal wt by ~ 35% compared to NMX in both sexes. Expression of IGF-2 was lower (p = 0.029) in NMX female placentas compared to males. Despite lower NMX levels, HPX increased (p < 0.05) expression of IGF-2, AKT-P, relative AKT-P, and PCNA in female placentas only and had no effect on protein expression in male placentas. The female guinea pig placenta exhibits a greater sensitivity than males to HPX in upregulating expression of the IGF-2 axis. In addition, the sex difference in baseline IGF-2 expression suggests a greater capacity for females to increase IGF-2 in response to HPX as a placental adaptation in FGR.

S17.3: Spatial gene expression analysis of the normal and cytomegalovirus‐infected guinea pig placenta

S17.3: Spatial gene expression analysis of the normal and cytomegalovirus‐infected guinea pig placenta

Maternal 3,3’-Diiodothyronine Sulfate Formation from Guinea Pig Placenta Perfused with 3,3’,5-Triodothyronine

Objective:Serum 3, 3’,5-triiodothyronine (T3) remains low in near-term fetus to prevent the growing fetus from undue exposure to its active catabolic effect in mammals. The present study was undertaken to gain insight in the role of placenta in T3 metabolism, fetal to maternal transfer of T3, and its metabolites by in situ placenta perfusion with outer-ring labeled [125I]-T3 in pregnant guinea pig, a species showing increased sulfated 3, 3’-diiodothyronine (T2S) levels in maternal serum in late pregnancy (term = 65 days), similarly to humans in pregnancy.Materials and Methods:One-pass placenta perfusions performed on pregnant guinea pigs were studied between 58 – 65 days of gestation. In two separate experiments, the umbilical artery of the guinea pig placenta was perfused in situ at 37°C with outer-ring labeled [125I]-T3. Maternal sera and umbilical effluents were obtained for analysis at the end of a 60-minute perfusion, when the steady-state levels of radioactivity were reached in the placenta effluent after 30-minute.Results:Sulfated [125I]-T2S was readily detected in the maternal serum as the major metabolite of T3 following the perfusion of placenta with [125I]-T3, suggesting that placental inner-ring deiodinase and sulfotransferase may play an important role in fetal T3 homeostasis and in the fetal to maternal transfer of sulfated iodothyronine metabolites.Conclusions:The expression of type 3 deiodinase (D3) and thyroid hormone sulfotransferase activity in placenta may play an important role to protect developing organs against undue exposure to active thyroid hormone in late gestation in the fetus. The combined activities of D3 and sulfotransferase promoted a placental transfer of T2S into maternal circulation. The maternal circulation of T2S is fetal T3 in origin and its role as a fetal thyroid function biomarker deserves further evaluations and studies.

Сравнительная характеристика аминокислотного состава и активности ферментов аминокислотного обмена в гемохориальной плаценте разных видов животных и человека

The amino acid composition and activity of the enzymes of the amino acid metabolism of placenta were studied. The objects of the study were guinea pigs (Cavia porcellus) and rhesus macaques (Macaca mulatta), which have a hemochoric placenta type, similar to humans. The study also included women with uncomplicated pregnancy and delivery on time (39-40 weeks). It was found that in the all tissues studied, the fetal part of the placenta is characterized by the highest content of free and bound amino acids. In the fetal part of the placenta, the maximal activity of amino acid metabolism enzymes (aminotransferases, deaminases, amino synthetases) was also found. Common to the placenta of guinea pigs, monkeys and humans is also a high level of dicarboxylic amino acids and glutamine. Along with the common features in the amino acid metabolism of the placenta of different species of animals and humans, some differences were revealed due to the evolutionary features of the development of the organ, the specifics of the existing maternal-fetal relationships. Interspecies differences of the same parts of the placenta relate to individual amino acids, the majority of which in the placenta of rodents exceeds similar indicators in primates. Between the placentas of humans and monkeys, the differences in the studied biochemical parameters are less pronounced. Another difference between guinea pig placenta and human and monkey placenta is the unequal non-covalent binding of amino acids to biopolymers, which modifies the state of the acceptor groups of proteins. Similar tissues of the afterbirth of different species of animals and humans differ in the activity of amino acid metabolism enzymes. There is a close correlation between the content of free amino acids and indicators of enzyme activity, showing their important role in the formation of the placental amino acid fund.

Identification of Eight Different Isoforms of the Glucocorticoid Receptor in Guinea Pig Placenta: Relationship to Preterm Delivery, Sex and Betamethasone Exposure.

The placental glucocorticoid receptor (GR) is central to glucocorticoid signalling and for mediating steroid effects on pathways associated with fetal growth and lung maturation but the GR has not been examined in the guinea pig placenta even though this animal is regularly used as a model of preterm birth and excess glucocorticoid exposure. Guinea pig dams received subcutaneous injections of either vehicle or betamethasone at 24 and 12 hours prior to preterm or term caesarean-section delivery. At delivery pup and organ weights were recorded. Placentae were dissected, weighed and analysed using Western blot to examine GR isoform expression in nuclear and cytoplasmic extracts. A comparative examination of the guinea pig GR gene identified it is capable of producing seven of the eight translational GR isoforms which include GRα-A, C1, C2, C3, D1, D2, and D3. GRα-B is not produced in the Guinea Pig. Total GR antibody identified 10 specific bands from term (n = 29) and preterm pregnancies (n = 27). Known isoforms included GRγ, GRα A, GRβ, GRP, GRA and GRα D1-3. There were sex and gestational age differences in placental GR isoform expression. Placental GRα A was detected in the cytoplasm of all groups but was significantly increased in the cytoplasm and nucleus of preterm males and females exposed to betamethasone and untreated term males (KW-ANOVA, P = 0.0001, P = 0.001). Cytoplasmic expression of GRβ was increased in female preterm placentae and preterm and term male placentae exposed to betamethasone (P = 0.01). Nuclear expression of GRβ was increased in all placentae exposed to betamethasone (P = 0.0001). GRα D2 and GRα D3 were increased in male preterm placentae when exposed to betamethasone (P = 0.01, P = 0.02). The current data suggests the sex-specific placental response to maternal betamethasone may be dependent on the expression of a combination of GR isoforms.

An Ex vivo culture model for placental cytomegalovirus infection using slices of Guinea pig placental tissue

Congenital infection with human cytomegalovirus (CMV) through the placenta is one of the major causes of birth and developmental abnormalities. Guinea pig CMV (GPCMV) causes in utero infection, which makes its animal models useful for studies on congenital diseases. Here, we established an ex vivo culture method for tissue slices prepared from guinea pig placentas and demonstrated that viral spread in the model resembles those in the placenta of GPCMV-infected animals and that the infection is independent of the pentameric glycoprotein complex for endothelial/epithelial cell tropism. Thus, this model affords a useful tool for pathobiological studies on CMV placental infection.

Identification of seven different isoforms of the glucocorticoid receptor in Guinea Pig placenta: relationship to preterm delivery, sex and betamethasone exposure

Identification of seven different isoforms of the glucocorticoid receptor in Guinea Pig placenta: relationship to preterm delivery, sex and betamethasone exposure

Chemotactic activity of gestational tissues through late pregnancy, term labor, and RU486-induced preterm labor in Guinea pigs.

Is increased leukocyte chemotactic activity (CA) from gestational tissues necessary for term or preterm labor in guinea pigs? Tissue extracts were prepared from pregnant guinea pig decidua-myometrium, cervix, fetal membranes (amniochorion), and placenta during early third trimester (n=8), term not in labor (TNL, n=5), and term spontaneous labor (TL, n=6), RU486-induced preterm labor (PTL, n=6), or controls (cPTL, n=5). Leukocyte CA was assessed using a modified Boyden chamber assay. Extract chemokine and maternal progesterone concentrations were quantified by enzyme immunoassay. Only the extracts from amniochorion demonstrated increased CA through late gestation and labor. In contrast, CA was decreased in extracts from amniochorion and cervix from animals after RU486-induced PTL. Maternal progesterone concentrations remained high in all groups. Leukocyte CA of intrauterine tissues is increased in term spontaneous labor. However, RU486-induced preterm labor occurs in the absence of increased CA.

PSS247 - Maternal Vitamin C Deficiency Depletes the Fetus and Does Not Modulate SVCT1 and 2 Expression in the Guinea Pig Placenta

PSS247 - Maternal Vitamin C Deficiency Depletes the Fetus and Does Not Modulate SVCT1 and 2 Expression in the Guinea Pig Placenta

Maternal undernutrition reduces P-glycoprotein in guinea pig placenta and developing brain in late gestation

Poor nutrition is a major cause of fetal growth restriction which increases neonatal morbidity and mortality, as well as the risk of adult onset diseases. The objective of the study was to determine the effect of maternal undernutrition on P-glycoprotein (P-gp) expression in the placenta and the brain of both the mother and the fetus. Maternal undernutrition in guinea pigs caused placental restriction, and thus decreased fetal weight. Pups in the maternal undernutrition (UN) group had fewer capillaries in the placenta and more capillaries in the brain of the fetus. Placental, maternal and fetal brain MDR1 mRNA expression was the same in the Control and UN groups. Maternal undernutrition resulted in a significant decrease in P-gp protein expression in the placenta and fetal brain, but not the maternal brain. These findings indicate that maternal undernutrition may impact on fetal exposure to drugs administered to the mother during pregnancy due to changes in placental transfer.

Human Antibodies Can Cross Guinea Pig Placenta and Bind Its Neonatal Fc Receptor: Implications for Studying Immune Prophylaxis and Therapy during Pregnancy

Despite increased use of monoclonal and polyclonal antibody therapies, including during pregnancy, there is little data on appropriate animal models that could humanely be used to understand determinants of protection and to evaluate safety of these biologics in the mother and the developing fetus. Here, we demonstrate that pregnant guinea pigs can transport human IgG transplacentally at the end of pregnancy. We also observe that human IgG binds to an engineered soluble variant of the guinea pig neonatal Fc receptor in vitro in a manner similar to that demonstrated for the human variant, suggesting that this transplacental transport mirrors the receptor-based mechanism seen in humans. Using an intravenous antihepatitis B-specific immune globulin preparation as an example, we show that this transport results in neutralizing activity in the mother and the newborn that would potentially be prophylactic against hepatitis B viral infection. These preliminary data lay the groundwork for introducing pregnant guinea pigs as an appropriate model for the evaluation of antibody therapies and advancing the health of women and neonates.

A syncytin-like endogenous retrovirus envelope gene of the guinea pig specifically expressed in the placenta junctional zone and conserved in Caviomorpha

Syncytins are genes of retroviral origin that have been co-opted by mammalian hosts for a function in placentation. Two such genes have already been identified in simians, as well as two distinct, unrelated ones in Muridae and a fifth in the rabbit.Here we searched for similar genes in the guinea pig, which belongs to the Caviomorpha lineage within the Hystricognathi suborder of rodents and displays a placental structural organization with several characteristic features comparable to those of the human organ, including deep trophoblast invasion of maternal tissues.An in silico search for envelope (env) genes with full coding capacity identified a candidate gene that showed specific expression in the placenta, as revealed by RT-qPCR using RNAs from a large panel of tissues. This gene belongs to an endogenous retroviral element present at a single-copy in the guinea pig genome, still displaying a retroviral organization – with a degenerate gag and pol, but an intact env gene. In situ hybridization of guinea pig placenta sections demonstrated specific expression at the level of the invasive trophoblast-containing junctional zone, as observed in humans for syncytin-1 and consistent with a role in invasion of the maternal uterine tissues. The identified gene displays a conserved open reading frame in the Caviomorpha, consistent with an entry date >30 million years, and sequence analyses showed purifying selection of the gene. Conclusively, despite the absence of a demonstrated fusogenic activity, it is likely that the identified env gene – that we named syncytin-like env-Cav1 – exerts a physiological function possibly related to trophoblast invasion, in the course of caviomorph placentation.

Lipophilicity is the Major Determinant of Permeability to a Range of Beta-Adrenoceptor Antagonists in the Fetally-Perfused Guinea-Pig Placenta

Lipophilicity is the Major Determinant of Permeability to a Range of Beta-Adrenoceptor Antagonists in the Fetally-Perfused Guinea-Pig Placenta

Drug Transfer in the Fetally-Perfused Guinea-Pig Placenta; Use of an Indicator Dilution Method

Drug Transfer in the Fetally-Perfused Guinea-Pig Placenta; Use of an Indicator Dilution Method

Expression of Toll-like Receptors 2 and 4 in Subplacental Trophoblasts From Guinea Pigs (Cavia porcellus) Following Infection WithCampylobacter jejuni

Toll-like receptors 2 and 4 (TLR2 and TLR4) are well-characterized cell surface receptors that recognize specific pathogen-associated molecular patterns and play an important role in pathogen recognition and activation of the innate immune system. Variable expression of TLR2 and TLR4 has been described in trophoblasts from normal and diseased placentas; yet, there are limited data regarding trophoblast TLR expression in response to specific placental pathogens, and TLR expression in the guinea pig placenta has not been described. The guinea pig is an effective model for Campylobacter-induced abortion of small ruminants, and the authors have shown by immunohistochemistry that C jejuni localizes within syncytiotrophoblasts of the guinea pig subplacenta. The present study was designed to determine if the expression of either TLR2 or TLR4 would be affected in subplacental trophoblasts following infection with C jejuni. Immunohistochemistry for TLR2 and TLR4 was performed on placenta from guinea pigs that aborted following inoculation with C jejuni and from sham-inoculated controls. Quantitative assessment of TLR expression was performed, and mean immunoreactivity for TLR2 was significantly higher in subplacental trophoblasts from animals that aborted compared with uninfected controls (P = .0283), whereas TLR4 expression was not statistically different (P = .5909). These results suggest that abortion in guinea pigs following infection with C jejuni is associated with increased TLR2 expression in subplacental trophoblasts and may reveal a possible role for TLR2 in the pathogenesis of Campylobacter-induced abortion.

139. PLACENTAL EXPRESSION OF microRNAs ALTERS WITH GESTATION IN THE GUINEA PIG

Functional development of the placenta ensures an adequate supply of nutrients for fetal growth throughout gestation. Placental nutrient transport capacity increases during gestation, through alterations in structure and abundance of its molecular determinants, including expression of Slc2a1 (glucose transporter type-1) and Slc38a2 (system A amino acid transporter), as well as Igf1and Igf2. Each of these genes are predicted targets of microRNAs. Non-coding RNAs can down-regulate, as well as activate translation, by interacting with complementary regions in the promoter, coding, or 3’UTR of target mRNAs.(1) MicroRNAs are present in the mammalian placenta,(2) but little is known about developmental changes in their expression and actions. We hypothesised that placental expression of microRNAs which target molecular mediators of nutrient transport changes during gestation. Expression of microRNAs in the guinea pig placenta was examined at D30 (n = 7) and D60 (n = 7) of gestation (term = D70) by Exiqon microarray. Gene expression was measured by real-time PCR. Predicted gene targets were identified using miRecords and networks and pathways by Ingenuity Pathway Analysis. Placental expression of 119 microRNAs was upregulated (P &lt; 0.05), and that of 40 was down-regulated (P &lt; 0.05), at late compared to early gestation. Of the 20 most abundant differentially up- or down-regulated microRNAs, 11 are predicted to target members of solute carrier families. This includes has-miR-26a (↑2X), which is predicted to target Slc38a2 mRNA and expression of has-miR-26a and Slc38a2 was positively correlated (P &lt; 0.02). Alternate predicted targets of has-miR-26a include networks involving amino acid metabolism, molecular transport and small molecular biochemistry. These findings support the hypotheses that gestational changes in microRNA expression act to regulate functional development of the placenta, including expression of genes that mediate nutrient transport. (1) Breving K, Esquela-Kerscher A. Int J Biochem Cell Biol 2009.(2) Barad O, et al. Genome Res 2004 14: 2486–2494.

Multidrug resistance phosphoglycoprotein (ABCB1) expression in the guinea pig placenta: developmental changes and regulation by betamethasone

Placental ABCB1 plays an important role in fetal protection against xenobiotics in the maternal circulation. Limited evidence indicates that glucocorticoids regulate ABCB1 expression in other tissues. Since approximately 10% of pregnant women are treated with synthetic glucocorticoids for threatened preterm labour, the effects of synthetic glucocorticoids on placental ABCB1 are important. We hypothesized that placental levels of ABCB1 are reduced in late gestation in the guinea pig and that synthetic glucocorticoids downregulate ABCB1 production. There was a significant decrease in placental Abcb1 mRNA expression in late gestation. Treatment of guinea pigs with betamethasone (1 mg/kg) on gestational days 40/41 and 50/51 resulted in a significant decrease in placental Abcb1 mRNA and protein expression. No sex differences were observed. Understanding the regulation of ABCB1 function will facilitate the development of treatment strategies for human fetal protection against maternally derived endobiotics and xenobiotics.

159. MATERNAL NUTRITION AND GESTATIONAL AGE AFFECT PLACENTAL microRNA EXPRESSION IN THE GUINEA PIG

Maternal undernutrition restricts placental growth and nutrient supply to the fetus, but induces compensatory alterations in structure and function of the placenta. Maternal undernutrition in guinea pigs also restricts placental growth and alters structure, and changes expression of Igf1, Igf2, Slc2a1, Slc38a2 mRNA in mid and late gestation, consistent with nutritionally induced changes in nutrient transport across the placenta. MicroRNAs are non-coding RNAs that regulate expression of target genes by translational inhibition and mRNA degradation and are present in the mammalian placenta. Effects of maternal undernutrition on their expression are unknown. We hypothesised that altered expression of key functional genes in the placenta in maternal undernutrition are in part due to altered expression of regulatory microRNAs. The effect of maternal food restriction on the expression of microRNAs in the guinea pig placenta was examined at D30 and D60 of gestation (term = D70). Guinea pigs were fed either ad libitum (AL) or restricted (R). MicroRNA expression was determined by Exiqon microarray v.8.1. In AL placentas, 119 microRNAs were upregulated (p&lt;0.05), whilst 40 were down-regulated (p&lt;0.05) at late compared to early gestation. In R placentas, 163 microRNAs were upregulated (p&lt;0.05), whilst 123 were down-regulated (p&lt;0.05) at late compared to early gestation. Of the 20 most abundant up-regulated microRNAs miR-Plus (ID 17871) and hsa-miR-411 were altered only in AL and hsa-miR-376a and -376b were altered only in R placenta. Of the 20 most abundant down-regulated microRNAs, 13 were altered only in AL and 14 only in R placentas. Placental expression of microRNAs changed with gestation, and maternal undernutrition modified this pattern and altered expression of many additional microRNAs in the guinea pig placenta. This suggests that miRNAs and factors that influence their expression may play a role in the structural and/or functional development of the placenta and hence fetal growth.

Maintaining the integrity of trophoblast during growth of the placenta. Focus on “Insulin-like growth factor I and II regulate the life cycle of trophoblast in the developing human placenta”

maternal-fetal exchange of nutrients and respiratory gases occurs across the brush border of the trophoblast lining the intervillous space of the placenta. The trophoblast is syncytial in nature and has a high rate of turnover. Therefore syncytiotrophoblast is continually replenished from an