No abstract

In this study, we report quantity, solubility and molecular polymorphism of collagen, proportional relationships between various types of collagen, ultrastructure of collagen fibres, the amounts of various glycosaminoglycans (GAGs) and proportional relationships between them in Wharton’s jelly of normal umbilical cords. We compare the extracellular matrix components in Wharton’s jelly with those in the umbilical cord artery. Collagen of the Wharton’s jelly demonstrates some specific features. It is very insoluble in neutral salt and in a slightly acidic solution and appears to be resistant to the action of depolymerizing agent (EDTA-Na₂). Only 50% of total collagen may be solubilized by pepsin digestion and fractionated by differential salt precipitation. Four collagen fractions were obtained. Three of them were identified by polyacrylamide gel electrophoresis as type I, type III, and type V collagen and proportional relationship between them was calculated. Hyaluronic acid is the most abundant component of GAGs contained in Wharton’s jelly. The amounts of sulphated GAGs – keratan sulphate, heparan sulphate, chondroitin-4-sulphate, chondroitin-6-sulphate, dermatan sulphate and heparin – are distinctly lower. Each of them constitutes only a few percent of total GAGs.

No abstract

Objective: The defects of collagen metabolism are responsible for the disorganization of extracellular matrix in stomach cancer. Collagen through interaction with integrin receptors regulates the cellular growth, differentiation, gene expression, prolidase and gelatinase activity and plays an important role in tumorigenesis and invasiveness. Although extracellular metalloproteinases initiate the breakdown of collagen in tissues, the final step of its degradation is mediated by prolidase. Therefore, we decided to compare the degradation of collagen in control tissues to gastric cancer tissues. Methods: We investigated the collagen content (hydroxyproline assay), expressions of β₁ integrin, prolidase and gelatinases A and B (Western immunoblot) as well activities of prolidase (colorimetric assay) and gelatinases (zymography) in stomach cancer tissue (n = 10). The results were compared with corresponding data obtained for control tissues (n = 10). Results: No differences in the collagen content were found between the studied tissue samples. However, an increase in free proline pool, enhanced gelatinase expression and elevated gelatinolytic activity were found in the tumor tissue. These phenomena were accompanied by a significant elevation in prolidase activity and an increase in β₁ integrin expression in stomach cancer, compared to control tissue. Conclusion: The data presented suggest an enhancement of collagen turnover in stomach cancer. It may be suggested that the increased degradation of collagen by gelatinase in cancer tissue is balanced by an increased biosynthesis of this protein.

Pre-eclampsia--edema, proteinuria, hypertension (EPH-gestosis) is one of the more common complications observed during pregnancy. The umbilical cord vein walls were taken from newborns delivered by healthy mothers (control material) and by mothers with polysymptomatic pre-eclampsia (investigated material). Normal saphenous vein walls were collected from adult subjects undergoing varicose vein surgery. The collagen content was measured by the assay of hydroxyproline. Elastin was determined according to Fastin Elastin Assay and gravimetrically. Glycosaminoglycans content was determined by uronic acids assay. The collagen content decreased in the pre-eclampsia material. The amount of soluble elastin increased in the investigated material. The insoluble elastin content decreased in the umbilical cord veins of newborns delivered by mothers with pre-eclampsia. Reconstructing the umbilical cord vein wall may disturb fetal blood flow and affect the vascular system in adulthood.

The amounts and activities of matrix metalloproteinases (MMPs) were studied in human myometrium and uterine leiomyomas in various stages of growth. It was found that both myometrium and the investigated tumors contain collagenolytic enzymes. MMP-1, MMP-2, MMP-3 and MMP-9 were found. Gelatinase A (MMP-2) is the most abundant. In control myometrium only 10% of this enzyme exists in an active form, whereas in tumors, especially in large ones, the values reach 30%. It is suggested that the high activity of MMP-2 is responsible for remodelling of extracellular matrix in the growing tumors.

No abstract

It was found that both normal human myometrium and uterine leiomyoma contain several glycosaminoglycans. In contrast to many normal and tumour tissues the amount of hyaluronic acid is very low and the proportional amount of sulphated glycosaminoglycans is distinctly higher. It is of interest that heparan sulphate is the major glycosaminoglycan component both in normal myometrium, and in leiomyoma. The amount of hyaluronic acid in myometrium and in the leiomyoma is very low. No significant change in hyaluronate content was observed during the tumour growth. In contrast to that the amount of some sulphated glycosaminoglycans (heparan sulphate, keratan sulphate, chondroitin sulphates and heparin) distinctly increased. It is suggested that some of the GAGs participate in the creation of a storage depot for biologically active molecules (growth factors, enzymes) which are thereby stabilized and protected. Hydrolytic degradation of some GAGs may result in the release of some cytokines which may promote the tumour growth and stimulate collagen biosynthesis by tumour cells.