Quantitative analysis of matrix metalloproteinases-2 and-9, and their tissue inhibitors-1 and-2 in human placenta throughout gestation

To elucidate the implication of type IV collagenases(MMP-2 and MMP-9) and t heir tissue inhibitors (TIMP-1 and TIMP-2) for placental development, we qu antified their levels in the conditioned media of placental organ culture a nd primary culture of the trophoblast as well as in the tissue extracts of placentas from different stages of gestation using specific enzyme-linked i mmunosorbent assays. First trimester villous tissue secreted about 10 times more pro-MMP-2 than pro-MMP-9, and pro-MMP-2 levels dramatically decreased in the second trimester. On the other hand, pro-MMP-9 levels were more tha n 10 times higher than those of pro-MMP-2 in the primary culture of the fir st trimester trophoblast, indicating the involvement of stromal cells for p rominent pro-MMP-2 secretion from first trimester villous tissue described above. Levels of TIMPs, especially those of TIMP-2, remained constant throu ghout gestation both in the culture media and tissue extracts. Gelatin zymo graphy revealed abundant:secretion of the active form of MMP-2 as well as p ro-MMP-2 from first trimester villous tissue. Western immunoblot analysis c onfirmed the presence of both TIMP-1 and TIMP-2 in placental tissue. These results suggest that active secretion of MMP-2 from villous tissue in the f irst trimester and constant production of TIMPs throughout gestation are ch aracteristic of placental development.