Changes in active and latent collagenase in human placenta around the time of parturition

The placenta is an organ that develops during pregnancy to provide nutrition, a means of respiratory gas exchange, hormones, and growth factors to the fetus. The placenta is a rich source of the fiber-like protein collagen, which is found in connective tissues such as skin, bone, ligaments, and cartilage. The placenta also contains enzymes called proteinases that break down structural proteins such as collagen. The enzyme collagenase, which specifically degrades collagen, may be important in dilating the opening of the uterus (cervix) during birth of the baby. The degradation of structural proteins such as collagen may also be important in the separation of the placenta from the wall of the uterus during birth. High levels of collagenase have been measured in fluids from the cervix and in the blood of women at the end of pregnancy. The collagenase content of the human placenta at the end of gestation, the role of circulating collagenase, and the changes that occur at childbirth were assessed. The active and latent forms of the enzyme collagenase were detected in the human placenta. A factor that prevents the action of collagenase was also detected in the placenta. When the collagenase inhibitor was inactivated, collagenase activity increased 12- to 17-fold. The levels of collagenase in the umbilical cord were lower than levels in the circulation of the mother. Collagenase detected in the circulation may originate from the placenta. (Consumer Summary produced by Reliance Medical Information, Inc.)