The ability of intermediate trophoblasts to invade maternal tissue during placentation depends on how well they can degrade the extracellular matrix. Invasion into the extracellular matrix requires many complex proteases. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) is a novel family of secreted metalloproteinases. The ADAMTS-1, -4, -5, and -14 subtypes are known to be expressed in human placenta, but little is understood about their expression patterns.
To examine the expression patterns of ADAMTS-1, -4, -5, and -14 in specific human placenta cell types during gestation and in gestational trophoblastic diseases.
Placental tissues were obtained from 25 pregnant women and 21 cases of gestational trophoblastic diseases (10 early complete moles, 3 placental site trophoblastic tumors, 4 invasive moles, and 4 choriocarcinomas). The expression of the 4 ADAMTS was analyzed by immunohistochemistry.
ADAMTS-1, -4, -5, and -14 were differentially expressed by the human placenta throughout gestation in a time-specific and cell type-specific manner, as well as in gestational trophoblastic diseases. ADAMTS-1 showed gradually strong staining intensity in gestational trophoblastic diseases according to the invasive potential but showed consistent strong intensity throughout normal placenta. ADAMTS-4 and ADAMTS-5 exhibited higher and restricted expression in first-trimester intermediate trophoblasts. They also exhibited comparably strong expression in gestational trophoblastic diseases. However, ADAMTS-14 expression remained unchanged throughout gestation.
The restricted expression pattern of ADAMTS-4 and ADAMTS-5 and their increased expression in gestational trophoblastic diseases suggest that these 2 ADAMTS subtypes are associated with a biological phenotype of trophoblasts involved in human placentation and the development of gestational trophoblastic diseases.