Proteases in the human full-term placenta

Abstract

Aminopeptidase A, not yet defined aminopeptidases and endopeptidases, dipeptidyl peptidase I, II and IV, gamma-glutamyl transferase and oxytocinase were investigated in the normal human full-term placenta using qualitative (catalytic) cytochemistry, isoelectric focusing, immunocytochemistry and kinetic fluorometry. Aminopeptidase A could be visualized cytochemically in the smooth muscle cells of the chorionic plate, stem villi and basal plate blood vessels. Aminopeptidases were found in connective tissue fibres of the chorionic plate, villous stroma, basal plate and paraplacenta. Dipeptidyl peptidase IV was detected at the same sites as the aminopeptidases and, in addition, in amniotic epithelial cells, fibroblasts of the villous stroma, endothelium of chorionic plate and villous blood vessels as well as in the basophilic cytotrophoblast cells (x-cells) of the basal plate and paraplacenta, and it possibly also occurred in some domains of the plasma membrane of the syncytiotrophoblast and cytotrophoblast cells. The x-cells surrounded the fetus in the form of a dipeptidyl peptidase IV-positive shell at the border to the mother. The enzyme represented the first specific marker for x-cells. Dipeptidyl peptidase I and II were primarily found in Hofbauer cells (macrophages) of the villous stroma, but also in the syncytiotrophoblast, other villous stromal cells and cells of the chorionic and basal plate. gamma-Glutamyl transferase was present in some connective tissue elements of the chorionic plate. Oxytocinase and endopeptidases were not detected. Isoelectric focusing of proteases revealed different molecular forms of dipeptidyl peptidase IV in the paraplacenta and villous tree, while the aminopeptidases shared the same pattern in both regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Histochemical Evaluation of Placental Dipeptidyl Peptidase IV (CD26) in Pre‐eclampsia: Enzyme Activity in Villous Trophoblast Indicates an Enhanced Likelihood of Gestational Hypertensive Disorders

“…Reaction product measured in tissue homogenates, however, is developed by concomitant trophoblastic and fetal blood vessel and stroma/PVCS action. Reutter et al' reported on high binding affinities of DPP IV to extracellular matrix proteins, particularly to collagen I which [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] " 4 4 n=31 n=10 n=5 perivascular sheath. Our own observations (unpublished data) revealed a trend in decreased PVCS areas during me-eclammia.…”

Fetal Gammaglutamyl Transferase Activity: Clinical Implication in Fetal Medicine

“…Our experience con firmed by other investigations confirms that fetal GGT activity shows little variation ac cording to gestational age in normal pregnan cies. Maternal GGT does not cross the placen tal barrier, and the placenta does not produce significant amounts of GGT [12]. Fetal serum and amniotic fluid GGT activity thus derives entirely from the fetus.…”

Molecular anatomy of the perivascular sheath in human placental stem villi: the contractile apparatus and its association to the extracellular matrix

“…Undulin may interact with CD44 in smooth muscle cells. Elastin fibers are composed of elastin and oxytalan microfibrils, the latter of which bind to fibronectin and collagen type I cytochemistry, the enzyme was localized in smooth muscle cells and myofibroblast subpopulations of the PVCS (Feller et al 1985;Gossrau et al 1987;Graf et al 1994). This suggests, as possible functions of DPP IV, that it may act as an adhesion molecule to attach collagen type I to the plasma membrane and/or may be involved in the degradation of extracellular matrix together with metalloproteinases (MMPs; McDonald and Barrett 1986;Basbaum and Werb 1996).…”