Antiphospholipid antibodies in implantation failures

Area of Science:

• Immunology
• Cell Biology
• Reproductive Biology

Background:

• Plasma membranes exhibit asymmetric distribution of amino phospholipids like phosphatidylserine (PS) and phosphatidylethanolamine (PE).
• This asymmetry is maintained by aminophospholipid translocase (flipase) and disrupted by scramblase during cell activation, injury, or apoptosis.
• Developing trophoblasts uniquely externalize PS during differentiation.

Purpose of the Study:

• To review the role of antiphospholipid antibodies (aPL) in implantation failure and pregnancy loss.
• To explore the impact of antibodies to PS (aPS) and PE (aPE) on trophoblast function and early embryogenesis.

Main Methods:

• Analysis of published and unpublished data.
• Review of experimental models (animal and in vitro) investigating aPL effects on trophoblast.
• Consideration of cell division mechanisms involving PE.

Main Results:

• Antiphospholipid antibodies (aPL), especially aPS, target trophoblasts, leading to destruction, inhibited syncytium formation, reduced hCG production, and limited invasion.
• Anticardiolipin (aCL) antibodies, though not present on trophoblasts, are implicated in pathology and cross-react with aPS.
• Antibodies to PE (aPE) are associated with recurrent pregnancy loss and may interfere with embryonic cell division.

Conclusions:

• A role for aPL in implantation failure and occult pregnancy loss is proposed.
• Further investigation into the mechanisms of aPE in early pregnancy complications is warranted.