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Potential role of macrophages as immunoregulators of pregnancy.

Mor G, Abrahams VM - Reprod. Biol. Endocrinol. (2003)

Bottom Line: While this is a critical aspect of reproductive immunology, it is also important to consider the function of the maternal immune system in the promotion of implantation and maintenance of pregnancy.Apoptosis or cell death is not the final stage in tissue development.One of the key requirements of apoptotic cell clearance is the resolution of inflammatory conditions, which, as in the case of pregnancy, may have lethal consequences.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06520, USA. gil.mor@yale.edu

ABSTRACT
The role of the maternal immune system during pregnancy has focused mainly on the aspect of immune tolerance to the invading trophoblast and, therefore, fetus. While this is a critical aspect of reproductive immunology, it is also important to consider the function of the maternal immune system in the promotion of implantation and maintenance of pregnancy. Apoptosis or cell death is not the final stage in tissue development. The quick and effective removal of apoptotic cells by tissue macrophages represents a vital process preventing "leak" of self-antigens and promoting the production of proliferative/survival factors. One of the key requirements of apoptotic cell clearance is the resolution of inflammatory conditions, which, as in the case of pregnancy, may have lethal consequences. This review will focus on decidual macrophages and their role on apoptosis and cell clearance during pregnancy.

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Differential Distribution of macrophages in normal pregnancy and pregnancy complicated with preeclamsia and IUGR. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast (A) ; in pre-eclampsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells (B). In the normal condition, macrophages promote trophoblast survival; while in the pathologic state induce apoptosis
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Figure 2: Differential Distribution of macrophages in normal pregnancy and pregnancy complicated with preeclamsia and IUGR. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast (A) ; in pre-eclampsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells (B). In the normal condition, macrophages promote trophoblast survival; while in the pathologic state induce apoptosis

Mentions: Macrophages are also located near the spiral arteries during trophoblast invasion and transformation. Previous studies, and ours, of placental bed specimens, demonstrate changes in the distribution of macrophages during pathologic conditions such as preeclampsia [50,51]. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast; in preeclamsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells. Their distribution resembles a barrier between the invading trophoblast and the spiral arteries (See Figure 2). In addition, Resiter et al [51] have reported that macrophages residing in excess in the placental bed of preeclamptic women are able to limit extravillous trophoblast invasion of spiral arteries segments through apoptosis mediated by the secretion of TNFα. We propose a differential role for uterine macrophages during trophoblast invasion/differentiation, according to their stage of activation. In normal pregnancies, macrophages function as support cells by facilitating trophoblast invasion through the placental bed. In pathologic conditions, macrophages function as a barrier for trophoblast invasion and differentiation by inducing trophoblast apoptosis and therefore preventing spiral arteries transformation (Figure 2).


Potential role of macrophages as immunoregulators of pregnancy.

Mor G, Abrahams VM - Reprod. Biol. Endocrinol. (2003)

Differential Distribution of macrophages in normal pregnancy and pregnancy complicated with preeclamsia and IUGR. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast (A) ; in pre-eclampsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells (B). In the normal condition, macrophages promote trophoblast survival; while in the pathologic state induce apoptosis
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC305335&req=5

Figure 2: Differential Distribution of macrophages in normal pregnancy and pregnancy complicated with preeclamsia and IUGR. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast (A) ; in pre-eclampsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells (B). In the normal condition, macrophages promote trophoblast survival; while in the pathologic state induce apoptosis
Mentions: Macrophages are also located near the spiral arteries during trophoblast invasion and transformation. Previous studies, and ours, of placental bed specimens, demonstrate changes in the distribution of macrophages during pathologic conditions such as preeclampsia [50,51]. While in normal pregnancies macrophages are located in the stroma surrounding the transformed spiral arteries and extravillous trophoblast; in preeclamsia macrophages are located within and around the spiral arteries separating them from the trophoblast cells. Their distribution resembles a barrier between the invading trophoblast and the spiral arteries (See Figure 2). In addition, Resiter et al [51] have reported that macrophages residing in excess in the placental bed of preeclamptic women are able to limit extravillous trophoblast invasion of spiral arteries segments through apoptosis mediated by the secretion of TNFα. We propose a differential role for uterine macrophages during trophoblast invasion/differentiation, according to their stage of activation. In normal pregnancies, macrophages function as support cells by facilitating trophoblast invasion through the placental bed. In pathologic conditions, macrophages function as a barrier for trophoblast invasion and differentiation by inducing trophoblast apoptosis and therefore preventing spiral arteries transformation (Figure 2).

Bottom Line: While this is a critical aspect of reproductive immunology, it is also important to consider the function of the maternal immune system in the promotion of implantation and maintenance of pregnancy.Apoptosis or cell death is not the final stage in tissue development.One of the key requirements of apoptotic cell clearance is the resolution of inflammatory conditions, which, as in the case of pregnancy, may have lethal consequences.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06520, USA. gil.mor@yale.edu

ABSTRACT
The role of the maternal immune system during pregnancy has focused mainly on the aspect of immune tolerance to the invading trophoblast and, therefore, fetus. While this is a critical aspect of reproductive immunology, it is also important to consider the function of the maternal immune system in the promotion of implantation and maintenance of pregnancy. Apoptosis or cell death is not the final stage in tissue development. The quick and effective removal of apoptotic cells by tissue macrophages represents a vital process preventing "leak" of self-antigens and promoting the production of proliferative/survival factors. One of the key requirements of apoptotic cell clearance is the resolution of inflammatory conditions, which, as in the case of pregnancy, may have lethal consequences. This review will focus on decidual macrophages and their role on apoptosis and cell clearance during pregnancy.

Show MeSH
Related in: MedlinePlus