Sheep Placenta Research Articles

Androgen Receptor in the Term Equine Placenta

The equine placenta is critical in maintaining pregnancy. Not only does it provide essential nutrients and gasses, but it also functions as an endocrine, paracrine, and autocrine organ. For example, it is one of the main sources of estrogen and progesterone in the latter stages of pregnancy. In addition to supplying hormones required for development and pregnancy maintenance, hormones supplied by both the mare and fetus act on the placenta to influence its development and function. The equine placenta possesses both estrogen and progesterone receptors, and a great deal is known about these hormones' effects on placental development. However, very little is known about how, or if, androgens interact with the placenta to affect placental development and/or maintenance. Androgen receptor (AR) has been identified in the placenta of humans, cows, sheep, and rats; however, little is known about its exact functions related to the placenta. The focus of this study was to confirm the presence of AR in the equine placenta. Three term equine placentas from normal pregnancies were utilized in this study. Reverse transcription polymerase chain reaction was used to identify mRNA encoding AR, and Western blotting confirmed the presence of AR protein within the equine placenta. The results of this study provide new insight into the presence of AR, similar to other species including the human, bovine, ovine, and murine placenta.

Placenta Peptide Can Protect Mitochondrial Dysfunction through Inhibiting ROS and TNF-α Generation, by Maintaining Mitochondrial Dynamic Network and by Increasing IL-6 Level during Chronic Fatigue.

Background: Level of fatigue is related to the metabolic energy available to tissues and cells, mainly through mitochondrial respiration, as well fatigue is the most common symptom of poorly functioning mitochondria. Hence, dysfunction of these organelles may be the cause of the fatigue seen in Chronic fatigue (CF). Placenta has been used for treatment of fatigue and various disease, moreover peptides has known protect mitochondrial viability, and alleviate fatigue. These properties of placenta and peptides may link with its effect on mitochondria; therefore, it is highly important to investigate the effectiveness of placenta peptide on fatigue and mitochondrial dysfunction.Methods: After administration of sheep placenta peptide (SPP) for 1 month, mice’s were forced to swim till exhaustion for 90 min to induce chronic fatigue. Electron microscopic examination of skeletal muscle mitochondrial structure, tissue Malondialdehyde (MDA), mitochondrial SOD and serum inflammatory cytokines level were investigated in order to determine the potential effect of SPP on mitochondria during CF. Rat skeletal muscle (L6 cell) were also treated with different concentration of SPP to determine the effect of SPP on cell viability using Thiazoyl blue tetrazolium assay.Results: Our finding revealed that forced swimming induced fatigue model can cause mitochondrial damage through Reactive oxygen species (ROS) mediated lipid peroxidation and Tumor Necrosis factor alpha (TNF-α) elevation. Whereas SPP protected fatigue induced mitochondrial dysfunction through preventing ROS and TNF-α generation, by maintaining mitochondrial dynamic network and by increasing serum IL-6 level.Conclusion: SPP can protect damage in mitochondrial components which will allow proper functioning of mitochondria that will in turn inhibit progression of chronic fatigue. Therefore, SPP may represent a novel therapeutic advantage for preventing mitochondrial dysfunction in patients with chronic fatigue.

Noninvasive high-intensity focused ultrasound treatment of twin-twin transfusion syndrome: A preliminary in vivo study.

We investigated the efficacy, maternofetal responses, and safety of using high-intensity focused ultrasound (HIFU) for noninvasive occlusion of placental vasculature compared to sham treatment in anesthetized pregnant sheep. This technique for noninvasive occlusion of placental vasculature may be translatable to the treatment of conditions arising from abnormal placental vasculature, such as twin-twin transfusion syndrome (TTTS). Eleven pregnant sheep were instrumented with maternal and fetal arterial catheters and time-transit flow probes to monitor cardiovascular, acid-base, and metabolic status, and then exposed to HIFU (n = 5) or sham (n = 6) ablation of placental vasculature through the exposed uterine surface. Placental vascular flow was occluded in 28 of 30 targets, and histological examination confirmed occlusion in 24 of 30 targets. In both HIFU and sham exposures, uterine contact reduced maternal uterine artery flow, but delivery of oxygen and glucose to the fetal brain remained normal. HIFU can consistently occlude in vivo placental vessels and ablate blood flow in a pregnant sheep model. Cardiovascular and metabolic fetal responses suggest that the technique is safe in the short term and potentially translatable to human pregnancy.

Serological and Molecular Evidence of Q Fever in Domestic Ruminants in Bangladesh.

The objective of this study was to know the herd and animal level prevalence of Q fever in domestic ruminants in some selected districts in Bangladesh. Randomly collected 111 bulk milk and 94 sera samples of cattle, sheep, and goats were tested by indirect ELISA (iELISA). DNA extracted from 23 aborted fetal membranes was analyzed by real time (rt) PCR. The positive cut-off value of iELISA in bulk milk and individual animal sera was ≥30% and ≥40%, respectively. The overall herd level prevalence of Q fever in dairy cattle was 15.6%. The prevalence of Q fever in dairy cattle was significantly higher in Sirajganj in comparison to Satkhira District (P < 0.01). The overall seroprevalence of Q fever in domestic ruminants was 5.06%. Although statistically insignificant, the seroprevalence of Q fever was relatively higher in sheep (9.52%) in comparison to goats (3.33%) and cattle (3.57%). Out of 23 aborted fetal membranes, only one sheep placenta was positive in rt PCR. Q fever is present in all of the three important species of domestic ruminants in Bangladesh. It may have some role in sheep abortion as the seroprevalence is relatively higher and also one sheep placenta is rt PCR positive.

Fetal-maternal nitrite exchange in sheep: Experimental data, a computational model and an estimate of placental nitrite permeability

IntroductionNitrite conveys NO-bioactivity that may contribute to the high-flow, low-resistance character of the fetal circulation. Fetal blood nitrite concentrations depend partly on placental permeability which has not been determined experimentally. We aimed to extract the placental permeability-surface (PS) product for nitrite in sheep from a computational model. MethodsAn eight-compartment computational model of the fetal–maternal unit was constructed (Matlab® (R2013b (8.2.0.701), MathWorks Inc., Natick, MA). Taking into account fetal and maternal body weights, four variables (PS, the rate of nitrite metabolism within red cells, and two nitrite distribution volumes, one with and one without nitrite metabolism), were varied to obtain optimal fits to the experimental plasma nitrite profiles observed following the infusion of nitrite into either the fetus (n = 7) or the ewe (n = 8). ResultsThe model was able to replicate the average and individual nitrite–time profiles (r2 > 0.93) following both fetal and maternal nitrite infusions with reasonable variation of the four fitting parameters. Simulated transplacental nitrite fluxes were able to predict umbilical arterial-venous nitrite concentration differences that agreed with experimental values. The predicted PS values for a 3 kg sheep fetus were 0.024 ± 0.005 l∙min−1 in the fetal–maternal direction and 0.025 ± 0.003 l∙min−1 in the maternal–fetal direction (mean ± SEM). These values are many-fold higher than the reported PS product for chloride anions across the sheep placenta. ConclusionThe result suggests a transfer of nitrite across the sheep placenta that is not exclusively by simple diffusion through water-filled channels.

Cytokine gene expression at the maternal-fetal interface after somatic cell nuclear transfer pregnancies in small ruminants.

The present retrospective study investigated pregnancy rates, the incidence of pregnancy loss and large offspring syndrome (LOS) and immune-related gene expression of sheep and goat somatic cell nuclear transfer (SCNT) pregnancies. We hypothesised that significantly higher pregnancy losses observed in sheep compared with goat SCNT pregnancies are due to the increased amounts of T-helper 1 cytokines and proinflammatory mediators at the maternal-fetal interface. Sheep and goat SCNT pregnancies were generated using the same procedure. Control pregnancies were established by natural breeding. Although SCNT pregnancy rates at 45 days were similar in both species, pregnancy losses between 45 and 60 days of gestation and the incidence of LOS were significantly greater in sheep than in goats. At term, the expression of proinflammatory genes in sheep SCNT placentas was increased, whereas that in goats was similar to that in control animals. Genes with altered expression in sheep SCNT placentas included cytotoxic T-lymphocyte-associated protein 4 (CTLA4), interleukin 2 receptor alpha (IL2RA), cluster of differentiation 28 (CD28), interferon gamma (IFNG), interleukin 6 (IL6), interleukin 10 (IL10), transforming growth factor beta 1 (TGFB1), tumor necrosis factor alpha (TNF-α), interleukin 1 alpha (IL1A) and chemokine (C-X-C motif) ligand 8 (CXCL8). Major histocompatibility complex-I protein expression was greater in sheep and goat SCNT placentas at term than in control pregnancies. An unfavourable immune environment is present at the maternal-fetal interface in sheep SCNT pregnancies.

The placenta shed from goats with classical scrapie is infectious to goat kids and lambs

The placenta of domestic sheep plays a key role in horizontal transmission of classical scrapie. Domestic goats are frequently raised with sheep and are susceptible to classical scrapie, yet potential routes of transmission from goats to sheep are not fully defined. Sparse accumulation of disease-associated prion protein in cotyledons casts doubt about the role of the goat's placenta. Thus, relevant to mixed-herd management and scrapie-eradication efforts worldwide, we determined if the goat's placenta contains prions orally infectious to goat kids and lambs. A pooled cotyledon homogenate, prepared from the shed placenta of a goat with naturally acquired classical scrapie disease, was used to orally inoculate scrapie-naı¨ve prion genotype-matched goat kids and scrapie-susceptible lambs raised separately in a scrapie-free environment. Transmission was detected in all four goats and in two of four sheep, which importantly identifies the goat's placenta as a risk for horizontal transmission to sheep and other goats.

Reorganization of actin cytoskeleton in L929 cells infected with Coxiella burnetii strains isolated from placenta and foetal brain of sheep (Sardinia, Italy).

Coxiella burnetii, the etiological agent of Q Fever, is a zoonotic pathogen distributed worldwide. It has been reported that virulent strains of C. burnetii are poorly internalized by monocytes compared to avirulent variants. Virulence is also associated to the formation of pseudopodal extensions and transient reorganization of filamentous actin. In this article, we investigated the ability of 2 Coxiella strains isolated from ovine aborted samples to induce reorganization of the actin cytoskeleton in mouse fibroblast cells. Cells were exposed for 24 and 48 hours to ovine placenta and foetal brain tissue homogenates and then analysed by polymerase chain reaction (PCR) in order to detect Coxiella infection. The formation of pseudopodal extensions, the polarized distribution of F‑actin, and the involvement of C. burnetii strain in cytoskeleton reorganization have been assessed using a laser scanning confocal fluorescence microscope. Results indicate that similarly to the virulent reference strain, strains of C. burnetii isolated from foetal brain induced morphological changes - modification in F‑actin distribution and in the localization of bacteria. By contrast, C. burnetii strain isolated from ovine placenta did not induce any significant change in L929 cell morphology. In conclusion, both C. burnetii strains isolated from ovine placenta and foetal brain were pathogenic causing ovine abortion, but in vitro the C. burnetii strain isolated from brain only was able to induce F‑actin reorganization in L929 infected cells.

39 PLACENTA ABNORMALITIES IN SHEEP SOMATIC CELL CLONES AT 20 DAYS OF GESTATION

Somatic cell nuclear transfer (SCNT) has a broad spectrum of potential applications, ranging from therapeutic cloning, production of transgenic animals, drug production, regenerative medicine and even for the rescue of endangered species. It is already more than 16 years since Dolly, first cloned mammal, was born, and many improvements in SCNT have been made by using different epigenetic and technical approaches but the efficiency is still disappointingly low. Only ~0.1 to 3% of reconstructed embryos develop to term. SCNT is associated with high rate of fetal, perinatal, and neonatal losses and production of abnormal offspring. Many factors have been implied in the pathogenesis of the NT fetal losses, but it seems that the highest incidence is placental abnormalities, confirmed by our first reports studied on full-term sheep placentas. Reports strongly suggest that post-mortality in cloned lambs is mainly caused by placental abnormalities such as placentomegaly, hypoplasia of trophoblastic epithelium, altered basement membrane, and reduced vascularisation. The pathogenesis of these changes is poorly understood, so here we analysed early sheep placenta (20 days) for better understanding of mechanisms involved. Blastocysts obtained by nuclear transfer of somatic cells (adult sheep fibroblasts) were transferred into recipient ewes. Naturally mated ewes were analysed as controls (CTR). Conceptuses were recovered at Day 20 of gestation. Then, part of their placentas were fixed for histological and transmission electron microscope (TEM) analysis; other parts of the tissues were snap frozen in liquid nitrogen for subsequent mRNA analysis. Expression of genes regulating vasculo- and angiogenesis (ANG1, ANG2, FGF-2, FGF-2R, VEGF, and Tie-2) as well as imprinted genes (IGF-2, H19, PHLDA-2) were analysed. Statistical analysis was performed using GraphPad software (GraphPad Software Inc., San Diego, CA, USA). Gene expression was analysed using the nonparametric Mann-Whitney test; P &lt; 0.05 was considered significant. Expression of all analysed imprinted genes as well as vasculo- and angiogenesis factors in NT placentas at Day 20 of development were down-regulated (v. CTR). Histological analysis showed reduced vascularization and increased apoptosis in placental tissue. The observation of ultrathin sections confirmed placental abnormalities. Cells presented decreased density of mature mitochondria, high number of cytoplasmic vacuolization, numerous cytoplasmic vesicles and autophagosomes, less developed cells to cell junctions, and disruption of chorionic villi, being irregularly and sparsely arranged. The results of the present study indicate that the placental abnormalities affecting particularly the vascular compartment start from early stage of placenta development. Moreover, imprinted genes, which have been already shown to determine the transport capacity of the placenta by regulating its growth, morphology and nutrient abundance, were deregulated in NT early placentas. All those factor can lead to the developmental failure of cloned fetuses.

Expression profile of imprinted genes and DNA methyl transferases in uniparental sheep placenta

Expression profile of imprinted genes and DNA methyl transferases in uniparental sheep placenta

Sex-specific differences in the sheep placenta

Sex-specific differences in the sheep placenta

Pathological and molecular study of mycotic abortion in ewes

The aims of the present study is to isolate the fungal species associated with ewe abortion and to examine the histopathological changes in the placenta associated with fungal isolates .In addition to study the genetic information of TNF alpha gene, intensity and score of TNF-alpha protein in aborted and normal placenta by PCR and IHC respectivly. Frozen placental tissue and paraffin embedded tissue belong to aborted and normal groups were used for assessment of TNF alpha gene by studying the genetic information of TNF-alpha gene in aborted and normal placental sample by PCR .immmunohistochemical study was carried out to determine TNF protein in the placental sample. The same frozen placenta tissue samples were also used for DNA extraction to detect TNF alpha gene in the two groups. A fragment of (238 bp ) of the TNF alpha gene was amplified by PCR using primers ,the sequence of sense and antisense primer for TNF alpha gene was: GAA TAC CTG GAC TAT GCC GA,CC TCA CTT CCC TAC ATC CCT (bp 238) Gene Bank: X56756. The study showed that 10 fungal species were isolated from aborted placenta with high percentage of these isolates was recorded in March ,.The fungal isolates were variable according to region of sample collecting ,high percentage in the AL-Manathera(36%),followed by Al-Kuzweenia (34%) and Al-Shabaka(30%).The fungal isolates include Coccidioides immitis (16%). Asperigllus.fumigitus (14%), Trichophyton, Rhodetella rubra, and Aspergillus.ochraus ,(10%) for each one . Candida kruzei,(8%). Aspergillus.flavus and Geotrichum ,6%) for each one . Prototheca..zopfi, Saccharomyces.cerevisia, Blast.capitatuss, Cryptococcus uniguttultus and Candida zeylanoides,(4%) for each one . This study revealed the presence of ~238bp band in addition to the ~300 ,400 and 600 bp desired fragment in PCR products that related to aborted samples compared to normal one .,this may be due to polymorphism within the TNF gene itself. We found a significant elevated TNF alpha protein in inflammatory cell (macrophage) of aborted sheep placenta (increasing of intensity and score), while no changes could be observed for pro-inflammatory molecules in the control sample (normal delivery) The current study expressed correlation between polymorphisms in TNF- alpha gene ,immunohistochimistry and the fungal isolated species. The histopathological examination showed acute suppurative placentitis, necrosis of chorion villi, congestion of blood vessels with fibrin deposition in the villus stroma and inter villus space, in addition to calcification in the villus stroma and sloughing and desquamation of cytotrophoblast .numerous yeast and spheriols were detected in the placental tissue by periodic acid Schiff reaction(PAS).

A fluorescent staining technique for studying vascularity and angiogenesis in interdigitated maternal and fetal villi of sheep placenta

The objective of this study was to improve detection of the blood vessel network in placenta while simultaneously distinguishing maternal from fetal villi for image analysis. Therefore, we developed a technique for dual fluorescent labeling of endothelial cells and fetal trophoblast. Placentomes (d90 and d130 of pregnancy) were fixed (10% formalin or Carnoy's soln) and paraffin embedded. Following antigen retrieval (50mM glycine, 1mM EDTA, 0.05% Tween 20, pH 9.0; 120 C, 10 min), maternal and fetal blood vessels were identified by immunofluorescent labeling with an antibody (c/n:ab28364, ABCAM) against CD31 antigen, and CF 633 conjugated IgG (c/n:20122, Biotium). The trophoblast layer was stained with FITC labeled BS1 lectin (c/n:FL‐1101; Vector; 20 μg/ml). CD31 labeling resulted in bright fluorescent localization of all blood vessels. Positive lectin staining of fetal trophoblast allowed differentiation of fetal and maternal compartments. Thus, CD31 staining along with fluorescently labeled lectin combined with microscopy and imaging techniques provide an excellent tool to study angiogenesis and vascular architecture in sheep placenta, and other tissues. Grants: Hatch ND1748; USDA‐NIFA 2011–67016‐30174.

Post-implantation mortality of in vitro produced embryos is associated with DNA methyltransferase 1 dysfunction in sheep placenta

Is DNA methyltransferase 1 (DNMT1) dysfunction involved in epigenetic deregulation of placentae from embryos obtained by assisted reproduction technologies (ARTs)? DNMT1 expression in growing placentae of in vitro produced (IVP) embryos is compromised and associated with pregnancy loss. DNMT1 maintains the methylation profile of genes during cell division. The methylation status of genes involved in placenta development is altered in embryos obtained in vitro. Disturbances in the epigenetic regulation of gene expression during placentogenesis could be involved in the frequent developmental arrest and loss of IVP embryos. Forty sheep were naturally mated (Group 1, CTR). IVP blastocysts (2-4 per ewe) were surgically transferred to the remaining 46 recipient sheep 6 days after oestrus (Group 2). Twenty-one recipients from Group 1 and 27 recipients from Group 2 were allowed to deliver in order to compare embryo survival in both groups at term (150 days). From the remaining recipients (n = 38), fetuses and placentae of both groups were recovered by paramedian laparotomy at Days 20, 22, 24, 26 and 28 of gestation. Immediately after collection, early placental tissues (chorion-allantois) were snap frozen in liquid nitrogen and DNMT1 expression and activity was evaluated. mRNA levels (for DNMT1, HDAC2, PCNA, DMAP1, MEST, IGF2, CDKN1C, H19) and the methylation status of H19 were also analyzed. Furthermore, embryo size and survival rate were measured. Our study shows that DNMT1 expression was reduced in early placentae from sheep IVP embryos. This reduction was associated with growth arrest and subsequent death of the sheep embryos. Conversely, normal levels of DNMT1 and its cofactors were observed in placentae from IVP embryos that survived this developmental bottleneck. Although DNA methylation machinery was severely compromised in IVP placentae only up to Day 24, the low DNMT1 enzymatic activity that persisted after this stage in IVP placentae was not lethal for the developing embryos. The studied genes represent only a small fraction of genes regulating DNA methylation. Further studies are needed to evaluate changes in the expression and methylation status of other genes that may lead to developmental arrest of IVP embryos. As this is the only study evaluating the functionality of DNMT1 machinery in placentae from ART embryos, studies on other species are needed to confirm if our observation may be applicable to all mammalian embryos produced in vitro. The knowledge about compromised activity of DNMT1 in placentae obtained from IVP embryos should stimulate detailed studies on the metabolic requirements of oocytes and embryos in order to adequately enrich the culture media.

Maternal administration of busulfan before in utero transplantation of human hematopoietic stem cells enhances engraftments in sheep

In utero transplantation (IUT) of human hematopoietic stem cells has been conducted in sheep, which are used as large animal models of human hematopoietic reconstitution and models for clinical IUT; however, the levels of engraftment have generally been low. Busulfan (BU), a myeloablative agent, is often administered to patients before hematopoietic stem cells transplantation to improve the engraftment. In this study, hematopoietic activity was evaluated in adult sheep after administering BU at different doses. Next, pregnant ewes were administered BU, and dams as well as their fetuses were evaluated, as BU readily crosses the sheep placenta. Then, the BU dose with the desired outcomes was selected and administered to pregnant ewes at 2 or 6 days before performing IUT using human cord blood CD34(+) cells. The engraftment was evaluated in recipients that underwent IUT in the presence or absence of BU. As a result, hematopoietic activity was safely and transiently suppressed in adult sheep treated with 5 to 7.5 mg/kg BU. BU crossed the sheep placenta, and fetal sheep were indeed conditioned by administering 3 mg/kg BU to pregnant ewes. Engraftment of human CD34(+) cells in fetal recipients was enhanced when IUT was carried out 6 days post-BU. Up to 3.3% engraftment levels (in terms of bone marrow colony-forming units) were achieved with the IUT of 0.72 to 2.4 million CD34(+) cells when BU was used. BU can be administered to pregnant ewes to effectively condition the fetal recipient for IUT with enhanced engraftment of donor cells.

Programming the offspring through altered uteroplacental hemodynamics: how maternal environment impacts uterine and umbilical blood flow in cattle, sheep and pigs

As placental growth and vascularity precedes exponential fetal growth, not only is proper establishment of the placenta important, but also a continual plasticity of placental function throughout gestation. Inadequate maternal environment, such as nutritional plane, has been documented to alter fetal organogenesis and growth, thus leading to improper postnatal growth and performance in many livestock species. The timing and duration of maternal nutritional restriction appears to influence the capillary vascularity, angiogenic profile and vascular function of the placenta in cattle and sheep. In environments where fetal growth and/or fetal organogenesis are compromised, potential therapeutics may augment placental nutrient transport capacity and improve offspring performance. Supplementation of specific nutrients, including protein, as well as hormone supplements, such as indolamines, during times of nutrient restriction may assist placental function. Current use of Doppler ultrasonography has allowed for repeated measurements of uterine and umbilical blood flow including assessment of uteroplacental hemodynamics in cattle, sheep and swine. Moreover, these variables can be monitored in conjugation with placental capacity and fetal growth at specific time points of gestation. Elucidating the consequences of inadequate maternal intake on the continual plasticity of placental function will allow us to determine the proper timing and duration for intervention.

The Effect of Ovine Placenta Extract, on Mammogenesis, Lactogenesis and Galactopoiesis in Sheep

The aim of the present study was to evaluate the effect of ovine placenta extract, obtained by affinity chromatography on immobilized wheat germ lectin, on mammogenesis, lactogenesis, and galactopoiesis in pregnant and lactating sheep. Placental extract (100 \mug/mL protein concentration) was subcutaneously injected to pregnant sheep in days 1, 4, 7, 10, and 13 of the experiment (totally 10 mL placenta extract/animal) alternatively on the right and left side of the neck. Placental extract induced a more intense development of udder parameters; udder circumference increase was of 16.73%, anteroposterior length increase was of 15.9%, and latero-lateral length of 11.1%. Placental extract administration resulted in 7.92% increase in milk yield. Lactating ewes were monitored for milk production for 6 days before the experiment, after placental extract administration from day 7 to day 14 of the experiment, twice a day, and they presented 14.14% higher milk yield in comparison with the control group, no significant differences in milk lactose and protein content, but an increase in milk fat (6.2%). It may be concluded that the glycoprotein or glycopeptide isolated from sheep placenta by affinity chromatography on wheat germ lectin increased mammogenesis, lactogenesis, and galactopoiesis in sheep.

Effects of Maternal Plane of Nutrition, Placental Tissue Type, and Stage of Gestation on 3B-Hydroxysteroid Dehydrogenase, 17A-Hydroxylase, and Aromatase Activity of Sheep Placenta.

Effects of Maternal Plane of Nutrition, Placental Tissue Type, and Stage of Gestation on 3B-Hydroxysteroid Dehydrogenase, 17A-Hydroxylase, and Aromatase Activity of Sheep Placenta.

Maternal obesity up-regulates inflammatory signaling pathways and enhances cytokine expression in the mid-gestation sheep placenta

Obesity in pregnant women is a growing public health concern. The placenta is a source of cytokines which can induce maternal gestational insulin resistance and alter nutrient transport to the fetus. Obesity induces placental inflammation at term, but the impact of obesity on placental inflammation earlier in pregnancy has not been defined. Using sheep as an experimental model, we hypothesized that maternal obesity (MO) would induce inflammation in the cotyledonary (COT) tissue of the placentome by mid-gestation. Nonpregnant ewes were randomly assigned to a control (C, 100% of NRC recommendations) or obese (OB, 150% of NRC) group from 60 days before conception to 75 day of gestation (dG), when ewes were necropsied and placental COT tissue collected for analyses. Free fatty acids content, triglyceride and cholesterol content were higher ( P < 0.05) in the fetal plasma of OB compared to C ewes on day 75. MO increased mRNA levels of toll-like receptor (TLR) 2 ( P < 0.05) and TLR4 ( P = 0.06), macrophage markers cluster of differentiation (CD)11b ( P = 0.06), CD14 and CD68 ( P < 0.05), and proinflammatory cytokines tumor necrosis factor (TNF)α ( P < 0.01), interleukin (IL)-6 ( P < 0.05), IL-8( P < 0.01) and IL-18 ( P = 0.06), in COT tissue. Inflammatory c-Jun N-terminal kinase (JNK)/c-Jun and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways were up-regulated ( P < 0.05) in COT of OB ewes. In conclusion, MO enhanced the placental inflammatory response in OB ewes at mid-gestation, possibly as a result of increased TLR4 and free fatty acids.

Maternal and fetal microvasculature in sheep placenta at several stages of gestation

Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi.