Expression of autotaxin, an ectoenzyme that produces lysophosphatidic acid, in human placenta.

PROBLEM: Lysophosphatidic acid (LPA) is a bioactive lipid mediator and thought to play an important role in pregnancy. Plasma LPA is produced by autotaxin (ATX), and ATX activity in plasma increases during pregnancy paralleled with gestational weeks and decreases to near the non-pregnant level soon after delivery. However, the source of increased ATX during pregnancy is still uncertain. We hypothesized that the source of increased ATX might be placenta. METHOD OF STUDY: We investigated the protein and mRNA expression of ATX in human placenta using immunohistochemistry and RT-PCR, respectively. RESULTS: At all 3 gestational trimesters, immunohistochemical staining for placenta tissues revealed the most marked positive staining of ATX protein in trophoblasts. Real-time PCR revealed that mRNA amounts of ATX in placenta tissues paralleled with gestational weeks, i.e. ATX level in plasma. CONCLUSION: These findings suggest that trophoblasts might produce ATX and its bioactive resultant substance, LPA, paralleled with gestational weeks.