Cytokines from the pig conceptus: roles in conceptus development in pigs

Abstract

Establishment of pregnancy in pigs involves maintaining progesterone secretion from the corpora lutea in addition to regulating a sensitive interplay between the maternal immune system and attachment of the rapidly expanding trophoblast for nutrient absorption. The peri-implantation period of rapid trophoblastic elongation followed by attachment to the maternal uterine endometrium is critical for establishing a sufficient placental-uterine interface for subsequent nutrient transport for fetal survival to term, but is also marked by the required conceptus release of factors involved with stimulating uterine secretion of histotroph and modulation of the maternal immune system. Many endometrial genes activated by the conceptus secretory factors stimulate a tightly controlled proinflammatory response within the uterus. A number of the cytokines released by the elongating conceptuses stimulate inducible transcription factors such as nuclear factor kappa B (NFKB) potentially regulating the maternal uterine proinflammatory and immune response. This review will establish the current knowledge for the role of conceptus cytokine production and release in early development and establishment of pregnancy in the pig.Electronic supplementary materialThe online version of this article (doi:10.1186/2049-1891-5-51) contains supplementary material, which is available to authorized users.

Within-litter variation in birth weight: impact of nutritional status in the sow

“…Implantation is a gradual process starting as early as Day 13 when elongation of the conceptus is underway and is well advanced by Day 18 of gestation (Perry et al, 1976), which is a determinant for establishing sufficient uterine surface area for placentation and subsequent nutrient transport for piglet survival and development (Geisert et al, 2014;. It should be emphasized that establishment of pregnancy (conceptus elongation and implantation) also involves maternal uterine pro-inflammatory and immune responses (Geisert et al, 2014), due to a number of cytokines released or stimulated by the elongating conceptuses, such as NF-κB (Hayden and Ghosh, 2012) and interleukin 1β (IL-1β) (Ross et al, 2003;Blomberg et al, 2005).…”

“…It should be emphasized that establishment of pregnancy (conceptus elongation and implantation) also involves maternal uterine pro-inflammatory and immune responses (Geisert et al, 2014), due to a number of cytokines released or stimulated by the elongating conceptuses, such as NF-κB (Hayden and Ghosh, 2012) and interleukin 1β (IL-1β) (Ross et al, 2003;Blomberg et al, 2005). In order to avoid rejection by the immune response, an increase in expression of both IL1B and estrogen by individual conceptuses counter-balances stimulation of the pro-inflammatory and immune response within the uterus (Geisert et al, 2014); thus elongating conceptus can attach across the uterine luminal epithelial surface successfully.…”

Implantation and Establishment of Pregnancy in the Pig

“…During conceptus elongation and the early peri-implantation period, the endometrium increases the release of a number of growth factors and cytokines such as epidermal growth factor (EGF), insulin-like growth factor-1 (IGF-1), fi broblast growth factor 7 (FGF7), vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), transforming growth factor beta (TGFβ), and leukemia inhibitory factor (LIF) (see review Bazer et al 2010 ;Geisert et al 2014 ). Endometrial release of EGF, FGF7, LIF, and IGF-1 is specifi cally enhanced in the epithelium during the period of conceptus elongation and estrogen secretion.…”

“…Although growth of the pig conceptuses is regulated through release of uterine growth factors during early development (Geisert et al 2014 ), rapid trophoblast elongation and estrogen secretion are triggered by conceptus development and cellular differentiation ( Fig. 8.2 ).…”

“…There is a clear spatiotemporal relationship between PGR downregulation and NFKB activation by IL1B2 from pig conceptuses (Mathew et al 2011 ). Conceptus elongation and IL1B2 release stimulate nuclear translocation of NFKB in LE adjacent to conceptuses during the establishment of pregnancy (see review Geisert et al 2014 ) Nuclear of translocation of the NFKB dimers stimulates transcription pathways involved in infl ammation, cell adhesion, cytokine release, anti-apoptotic factors, and immunoreceptors (Hayden and Ghosh 2012 ). Many cytokines (TNFα, IL1, IL2, IL6, IL12, LIF, and GMCSF), chemokines (IL8 and RANTES), and PTGS2 are transcriptionally regulated by NFKB (Ali and Mann 2004 ).…”