EPH-gestosis (pre-eclampsia)-induced decrease of gelatinase activity may promote an accumulation of collagen in the umbilical cord artery

Abstract

It was found in our previous paper that edema, proteinuria, hypertension (EPH)-gestosis-associated accumulation of collagen in the umbilical cord artery (UCA) is a result of increased biosynthesis and decreased degradation of this protein. It is known that the activity of collagenolytic enzymes is a main factor regulating collagen degradation rate in various tissues. For this reason it was decided to evaluate the effect of EPH-gestosis on the activity of proteolytic enzymes which may be involved in collagen degradation in the UCA wall. Proteolytic activity against bovine serum albumin, reconstituted collagen fibres and gelatin were evaluated. Latent forms of proteolytic enzymes were activated by the action of trypsin, p-chloromercuric benzoate (PCMB) and p-aminophenylmercuric acetate (APMA). A low activity of gelatinase (type IV collagenase) was detected in the extracts from the wall of the umbilical cord artery. This enzyme increased its activity several times after the action of trypsin, PCMB and APMA. EPH-gestosis results in a distinct reduction in gelatinase activity. Despite the action of activating agents the gelatinase from EPH-gestosis UCAs was considerably lower in comparison to control UCAs. It can be concluded that gelatinase of the umbilical cord artery forms an inactive complex with a tissue inhibitor of metalloproteinases. Such a complex dissociates under the action of trypsin, PCMB or APMA or sodium dodecyl sulphate. The decrease of gelatinolytic activity in the umbilical cord artery may be a factor that reduces the breakdown of collagen in the arterial wall and promotes an accumulation of this protein. The accumulation of collagen with simultaneous reduction in elastin content in the UCA may be the factors which reduce the elasticity of arterial wall and decrease the blood flow in the fetus of woman with EPH-gestosis.