Histochemical localization of acidic glycosaminoglycans in normal human placentae

First-trimester and term placentae were studied histochemically with alcian blue stain before and after specific enzyme treatments. A specific deposition of glycosaminoglycans was detected in the villous stroma, fetal blood vessels and on the surface of the syncytiotrophoblast, the latter being discontinuous and of variable thickness. Treatments of sections with hyaluronidases from Streptomyces and from bovine testes and with chondroitinase ABC indicated the presence of (1) chondroitin sulphates and hyaluronic acid mainly in the stroma; (2) heparan sulphate and dermatan sulphate associated with villous fetal blood vessels and the intervillous surface of the syncytiotrophoblast. It is suggested that the location of individual glycosaminoglycans could be related to their functions with regard to the maintenance of the structural integrity of the placenta by preventing its compression and to their involvement in blood anticoagulation and in lipid metabolism.