Establishment of Pregnancy in the Pig: II. Cellular Remodeling of the Porcine Blastocyst During Elongation on Day 12 of Pregnancy12

Geisert, R. D.; Brookbank, John W.; Roberts, R. Michael; Bazer, Fuller W.

doi:10.1095/biolreprod27.4.941

Cited by 265 publications

(254 citation statements)

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“…Between Days 10 and 12 of gestation, the porcine embryo undergoes a process known as elongation, transforming from an approximately 1-mm spherical structure to a long, thin filament that is .100 mm in length (Geisert et al 1982a;Pusateri et al 1990). Unlike elongation in other domestic species, rapid elongation of the pig embryo occurs via cellular remodelling and differentiation of the trophectoderm rather than cellular hyperplasia 1 USDA is an equal opportunity provider and employer.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike elongation in other domestic species, rapid elongation of the pig embryo occurs via cellular remodelling and differentiation of the trophectoderm rather than cellular hyperplasia 1 USDA is an equal opportunity provider and employer. (Geisert et al 1982a;Pusateri et al 1990). During elongation, the embryo produces and secretes oestrogen, which serves as a key molecular signal for maternal recognition of pregnancy and modulates the production of proteins and growth factors within the uterus (Geisert et al 1982b).…”

Section: Introductionmentioning

confidence: 99%

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In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

Sargus-Patino

Wright

Plautz

et al. 2014

Reprod. Fertil. Dev.

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Abstract. Between Days 10 and 12 of gestation, porcine embryos undergo a dramatic morphological change, known as elongation, with a corresponding increase in oestrogen production that triggers maternal recognition of pregnancy. Elongation deficiencies contribute to embryonic loss, but exact mechanisms of elongation are poorly understood due to the lack of an effective in vitro culture system. Our objective was to use alginate hydrogels as three-dimensional scaffolds that can mechanically support the in vitro development of preimplantation porcine embryos. White cross-bred gilts were bred at oestrus (Day 0) to Duroc boars and embryos were recovered on Days 9, 10 or 11 of gestation. Spherical embryos were randomly assigned to be encapsulated within double-layered 0.7% alginate beads or remain as non-encapsulated controls (ENC and CONT treatment groups, respectively) and were cultured for 96 h. Every 24 h, half the medium was replaced with fresh medium and an image of each embryo was recorded. At the termination of culture, embryo images were used to assess morphological changes and cell survival. 17b-Oestradiol levels were measured in the removed media by radioimmunoassay. Real-time polymerase chain reaction was used to analyse steroidogenic transcript expression at 96 h in ENC and CONT embryos, as well as in vivo-developed control embryos (i.e. spherical, ovoid and tubular). Although no differences in cell survival were observed, 32% (P , 0.001) of the surviving ENC embryos underwent morphological changes characterised by tubal formation with subsequent flattening, whereas none of the CONT embryos exhibited morphological changes. Expression of steroidogenic transcripts STAR, CYP11A1 and CYP19A1 was greater (P , 0.07) in ENC embryos with morphological changes (ENCþ) compared with CONT embryos and ENC embryos with no morphological changes (ENCÀ), and was more similar to expression of later-stage in vivo-developed controls. Furthermore, a time-dependent increase (P , 0.001) in 17b-oestradiol was observed in culture media from ENCþ compared with ENCÀ and CONT embryos. These results illustrate that preimplantation pig embryos encapsulated in alginate hydrogels can undergo morphological changes with increased expression of steroidogenic transcripts and oestrogen production, consistent with in vivo-developed embryos. This alginate culture system can serve as a tool for evaluating specific mechanisms of embryo elongation that could be targeted to improve pregnancy outcomes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

Sargus-Patino

Wright

Plautz

et al. 2014

Reprod. Fertil. Dev.

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“…Unlike human and mouse blastocysts, the hatched ungulate blastocyst remains detached in the uterus, and transitions through a phase of rapid trophoblast development that dramatically alters the blastocyst morphology prior to implantation. Elongation, i.e., the lengthening and morphological transition of the conceptus' extraembryonic tissues from a sphere to ovoid to tubule to filament, occurs in all ungulates during peri-implantation and is concomitant with gastrulation (Geisert et al 1982, Bazer et al 1993, Hue et al 2001. The expansion of the trophoblast provides an increased placental surface area to enable maternal:conceptus cross-talk and nutrient exchange that are essential for the survival of the conceptus (Stroband & Van der Lende 1990).…”

Section: Introductionmentioning

confidence: 99%

“…The bovine conceptus size increases more than 1000-fold during elongation (Maddox-Hyttel et al 2003) and is accomplished by an increase in cell number and accompanying protein synthesis (Thompson et al 1998, Degrelle et al 2005. However, the rate and extent of morphological change of the blastocyst is unsurpassed in pig as the conceptus elongates from an ovoid of !10 mm to a long thin filament O150 mm within w4 h between gd11and gd12 (Anderson 1978, Geisert et al 1982.…”

Section: Introductionmentioning

confidence: 99%

Blastocyst elongation, trophoblastic differentiation, and embryonic pattern formation

Blomberg¹,

Hashizume²,

Viebahn³

2008

Reproduction

106

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The molecular basis of ungulate and non-rodent conceptus elongation and gastrulation remains poorly understood; however, use of stateof-the-art genomic technologies is beginning to elucidate the mechanisms regulating these complicated processes. For instance, transcriptome analysis of elongating porcine concepti indicates that protein synthesis and trafficking, cell growth and proliferation, and cellular morphology are major regulated processes. Furthermore, potential autocrine roles of estrogen and interleukin-1-b in regulating porcine conceptus growth and remodeling and metabolism have become evident. The importance of estrogen in pig is emphasized by the altered expression of essential steroidogenic and trophoblast factors in lagging ovoid concepti. In ruminants, the characteristic mononucleate trophoblast cells differentiate into a second lineage important for implantation, the binucleate trophoblast, and transcriptome profiling of bovine concepti has revealed a gene cluster associated with rapid trophoblast proliferation and differentiation. Gene cluster analysis has also provided evidence of correlated spatiotemporal expression and emphasized the significance of the bovine trophoblast cell lineage and the regulatory mechanism of trophoblast function. As a part of the gastrulation process in the mammalian conceptus, specification of the germ layers and hence definitive body axes occur in advance of primitive streak formation. Processing of the transforming growth factor-b-signaling molecules nodal and BMP4 by specific proteases is emerging as a decisive step in the initial patterning of the pre-gastrulation embryo. The topography of expression of these and other secreted molecules with reference to embryonic and extraembryonic tissues determines their local interaction potential. Their ensuing signaling leads to the specification of axial epiblast and hypoblast compartments through cellular migration and differentiation and, in particular, the specification of the early germ layer tissues in the epiblast via gene expression characteristic of endoderm and mesoderm precursor cells.

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“…In this process, embryos and endometrial cells interact to produce a distinctive uterine environment with a typical pattern of cytokines, steroid hormones, growth factors and other metabolites such as prostaglandins [particularly prostaglandin E 2 (PGE 2 )]. All these metabolites are involved in the regulation of cell differentiation and the maturation and modulation of the endometrial immune environment to favor embryo development and suppress maternal rejection of conceptuses (Robertson et al 1994;Geisert et al 1982a;Clark and Croitoru 2001).…”

Section: Avenues For Explaining the Role Of Folic Acid In Reproductionmentioning

confidence: 99%

Folic acid and vitamin B₁₂ in reproducing sows: New concepts

Matte¹,

Guay²,

Girard³

2006

Can. J. Anim. Sci.

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Matte, J. J., Guay F. and Girard, C. L. 2006. Folic acid and vitamin B 12 in reproducing sows: New concepts. Can. J. Anim. . In pig nutrition, the present gaps in the information on B-complex vitamins have important implications for empiricism and disparities in dietary recommendations. This is particularly true for folic acid (B 9 ) and vitamin B 12 . Recent studies suggest that the beneficial effects of B 9 on sow prolificacy may be due to enhanced embryo development and survival. Embryo synthesis of estrogens and uterine secretions of prostanoids and cytokines during attachment appear to be key factors in vitamin B 9 regulation of embryo development. Nevertheless, embryo and uterine responses to B 9 are often more pronounced in multiparous sows than in gilts. This parity effect on B 9 responses can be attributed to the metabolic interaction with another vitamin, specifically B 12 . The two vitamins are essential for modulating the transfer of one-carbon groups for protein and DNA synthesis, methylation and gene expression. The metabolic pathway involved is the remethylation of methionine from an intermediary metabolite, homocysteine. A deficiency in B 9 or B 12 may induce a local or systemic accumulation of homocysteine, a powerful pro-oxidant known to impair embryo development. It appears that B 12 status, which is about two times lower in gilts than in multiparous sows, could be a limiting factor for the action of vitamin B 9 on uterus and embryo metabolism during the first pregnancy. Vitamin B 12 status is particularly critical since, in early gestation, the sow uterus drains off a massive amount of B 12 , representing two to three times the B 12 plasma pool. Dietary B 12 , at levels 10 times higher than recommended, have been found to maximize B 12 status and minimize homocysteine accumulation in first parity sows. It appears that an optimum B 9 :B 12 ratio, which has yet to be estimated, would enable vitamin B 9 to have full beneficial effects on sow prolificacy. In the future, it is likely that there will be an even greater need for updated information on the requirements for B-complex vitamins given the "dietary fine tuning" that is necessary for the highly producing pigs that have been selected in recent decades. Des études récentes suggèrent que les effets bénéfiques de la B 9 sur la prolificité de la truie seraient dus à un développement accéléré et à une meilleure survie de l'embryon. La synthèse d'oestrogènes par les embryons ainsi que les sécrétions utérines de prostanoïdes et de cytokines pendant l'implantation apparaissent comme des facteurs déterminant de l'effet régulateur de l'acide folique sur le développement et la survie de l'embryon. Néanmoins, ces effets embryonnaires et utérins de l'acide folique sont souvent plus marqués chez les truies multipares que chez les cochettes. Cet effet de la parité sur la réponse à la B 9 pourrait être attribué à une autre vitamine, la B 12 . Ces deux vitamines interviennent dans le transfert d'unités monocarbonées essentielles à la synthèse de protéine, ...

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Establishment of Pregnancy in the Pig: II. Cellular Remodeling of the Porcine Blastocyst During Elongation on Day 12 of Pregnancy12

Cited by 265 publications

References 16 publications

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

Blastocyst elongation, trophoblastic differentiation, and embryonic pattern formation

Folic acid and vitamin B₁₂ in reproducing sows: New concepts

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Establishment of Pregnancy in the Pig: II. Cellular Remodeling of the Porcine Blastocyst During Elongation on Day 12 of Pregnancy12

Cited by 265 publications

References 16 publications

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

In vitro development of preimplantation porcine embryos using alginate hydrogels as a three-dimensional extracellular matrix

Blastocyst elongation, trophoblastic differentiation, and embryonic pattern formation

Folic acid and vitamin B12 in reproducing sows: New concepts

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Product

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Folic acid and vitamin B₁₂ in reproducing sows: New concepts