Placental expression and localization of endothelin-1 system and nitric oxide synthases during bovine pregnancy

Timing and duration of nutrient restriction and its impacts on placental development and umbilical blood flow in adolescent sheep

We hypothesized that nutrient restriction from day 50-90 of gestation decreases umbilical blood flow and that umbilical blood flow would recover to control values upon realimentation during late gestation (d 90 to 130) or remain reduced in ewes that continued to be nutrient restricted. On d 50 of gestation, young nulliparous whiteface ewes (6-8 mo; n = 41) carrying singletons were randomly assigned to two dietary treatments: 100% of NRC recommendations (CON) or 60% of CON (RES). On d 90 of gestation, ewes either remained on CON or RES until d 130, or CON ewes were RES from d 90 to 130, or RES ewes were realimented to CON from d 90 to 130. This resulted in 4 treatment groups on day 130: CON-CON, CON-RES, RES-RES, RES-CON. Umbilical blood flow and fetal and placental measurements were obtained via ultrasonography every 10 days from day 50-110. Non-survival surgeries were performed on days 50, 90, and 130 (n = 6-7 ewes/group) where uterine artery and umbilical blood flows were measured during surgery via ultrasonography. Conceptus weights were recorded and placentomes collected to determine binucleate cell numbers. The study was conducted as a completely randomized design arrangement with repeated measures. Data were analyzed using the MIXED procedure of SAS. There was a nutritional treatment by day interaction (P < 0.01) with CON ewes having greater umbilical blood flow compared with RES by d 90. Fetal biparietal distance, abdominal width, and kidney area increased (P < 0.05) in CON-RES with all these measurements increasing during late gestation. We partially accept our hypothesis as nutrient restriction during mid gestation decreased umbilical blood flow. However, blood flow did not return to control levels upon realimentation. By d 130, fetal and placental weights were similar between RES-RES and CON-CON. Binucleate cell numbers in the fetal trophoblast were not influenced by nutritional treatments. Our findings suggest that refeeding previously nutrient restricted pregnant adolescent ewes to control levels does not reestablish umbilical blood flow. Adequate placental development during mid gestation could protect the fetus from a decreased umbilical blood flow later in gestation when nutrients were limited by 40%.

Pravastatin therapy during preeclampsia prevents long-term adverse health effects in mice

Preeclampsia (PE), associates with long-term increased risk for cardiovascular disease in women, suggesting that PE is not an isolated disease of pregnancy. It is not known if increased risk for long-term diseases is due to PE-specific factors or to prepregnancy renal and cardiovascular risk factors. We used a mouse model in which a WT female with normal prepregnancy health develops PE to investigate if preeclampsia causes long-term cardiovascular consequences after pregnancy for mothers and offspring. Mothers exhibited endothelial dysfunction and hypertension after PE and had glomerular injury that not only persisted but deteriorated, leading to fibrosis. Left ventricular (LV) remodeling characterized by increased collagen deposition and MMP-9 expression and enlarged cardiomyocytes were also detected after PE. Increased LV internal wall thickness and mass, increased end diastolic and end systolic volumes, and increased stroke volume were observed after PE in the mothers. Placenta-derived bioactive factors that modulate vascular function, markers of metabolic disease, vasoconstrictor isoprostane-8, and proinflammatory mediators were increased in sera during and after a preeclamptic pregnancy in the mother. Offspring of PE mice developed endothelial dysfunction, hypertension, and signs of metabolic disease. Microglia activation was increased in the neonatal brains after PE, suggesting neurogenic hypertension in offspring. Prevention of placental insufficiency with pravastatin prevented PE-associated cardiovascular complications in both mothers and offspring. In conclusion, factors that develop during PE have long-term, cardiovascular effects in the mother and offspring independent of prepregnancy risk factors.

Relationship of progesterone, bovine pregnancy-associated glycoprotein-1 and nitric oxide with late embryonic and early fetal mortalities in dairy cows

The aim of the present study was to determine the relationship of progesterone (P4), bovine pregnancy-associated glycoprotein-1 (bPAG-1) and nitric oxide (NO) levels with late embryonic (LEM; day 28 to day 42) and early fetal mortalities (EFM; > day 42 to day 56) in dairy cows. Transrectal ultrasonography (6-8 MHz) was performed in 100 Holstein-Friesian cows at days 28, 42 and 56 after artificial insemination (AI; day 0) to diagnose pregnancy and to monitor the fate of the embryo. After ultrasound scanning of each cow, a milk sample was collected for assessment of P4 by an ELISA test and a blood sample was collected for assessment of bPAG-1, by using a double-antibody radioimmunoassay, and serum NO metabolites (nitrate + nitrite). Based on ultrasonographic examinations and bPAG-1-RIA, 41 of 100 inseminated cows were confirmed pregnant at day 28 after AI. Nine cows suffered of LEM, and 6 cows suffered of EFM and the overall pregnancy loss rate was 36.6% (15/41) between days 28 and 56 of pregnancy. By logistic regression analysis, there were no significant relationships between the level of P4 and bPAG-1 at day 28 after AI and the occurrence of LEM and EFM. Also, there were no significant relationships between the levels of P4 and bPAG-1 at day 42 and the occurrence of EFM. On the other hand, a significant relationship (P<0.05) was found between NO level at day 28 and the occurrence of LEM. In conclusion, measurement of the serum NO concentration at day 28 of pregnancy might help to predict the outcome of pregnancy by day 42 in dairy cows but further studies are needed to confirm this.

Temporo-spatial expression of adrenomedullin and its receptors in the bovine placenta

BACKGROUND

Adrenomedullin (AM) is a potent vasodilator peptide and is also involved in various physiological activities. In humans and rodents, AM is found in the uteroplacental unit and may be responsible for fetal development and maintenance of placental function. This study investigated 1) the mRNA expression patterns of AM and its receptor components (calcitonin receptor-like receptor (CRLR), receptor activity modifying protein (RAMP) 2 and RAMP3) during pregnancy and 2) mRNA and protein localization of AM, CRLR and RAMPs in the bovine placentome.

METHODS

For real-time quantitative RT-PCR, bovine uteroplacental tissues were collected from Day 25, 60, 100, 150, 200 and 250 of gestation and separated into uterine caruncle (CAR), intercaruncular endometrium (ICAR), extra-embryonic membranes on Day 25 and cotyledonary villous after Day 60 (EEM-COT) and intercotyledonary chorion (ICOT). In situ hybridization and immunohistochemistry was performed to investigate the cellular localization of mRNA and protein of AM, CRLR, RAMP2 and RAMP3 in the placentome on Day 56, 150 and 230 of gestation and interplacentomal tissues on Day 56 of gestation.

RESULTS

AM mRNA was highly expressed on Day 200 in EEM-COT, CAR and ICAR. CRLR mRNA was highly expressed on Day 60 in all portions. RAMP2 mRNA was also highly expressed on Day 60 in ICOT and ICAR. In EEM-COT, mRNA expression of CRLR and RAMP2 decreased from Day 150 to 250. RAMP3 mRNA was highly expressed on Day 150 in EEM-COT, ICOT and ICAR. A distinct AM mRNA and protein signal were only found in trophoblast binucleate cells (BNCs), whereas those of CRLR, RAMP2 and RAMP3 were detected in cotyledonary villous and caruncular epithelial cells. In interplacentomal tissues, AM was detected in BNCs of fetal membrane and a small part of luminal epithelium, endothelial lineage of blood vessels and glandular epithelium of the endometrium. Distinct signals of CRLR, RAMP2 and RAMP3 were found in trophoblast cells, luminal epithelium, stroma under the epithelium, endothelial lineage of blood vessels and glandular epithelium.

CONCLUSIONS

Our results indicate that the AM system in the bovine uteroplacental unit may be activated at placentation and transition from the mid to late gestation period. Locally produced AM in the BNCs may play a crucial role in regulation of placental vascular and cellular functions during pregnancy.