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Background: Our previous studies demonstrated that preeclampsia is accompanied by significant alterations in the amounts of peptide growth factors in the umbilical cord serum. Some of these factors (especially IGF-1) are known as regulators of collagen metabolism. The umbilical cord arteries (UCAs) of newborns delivered by mothers with preeclampsia contain more than twice the amount of collagen in comparison to newborns delivered by healthy mothers. A significant role in collagen degradation is attributed to matrix metalloproteinase (MMP)-1 (collagenase 1) and tissue inhibitors of metalloproteinases (TIMPs). Objective: To compare the effects of umbilical cord (UC) blood serum of control and preeclamptic newborns on the content and activity of MMP-1, TIMP-1 and TIMP-2 in UCA wall slices incubated in vitro. Methods: Polyacrylamide gel electrophoresis (PAGE) followed by Western immunoblotting allowed to detect MMP-1 as well as TIMP-1 and TIMP-2. The amounts of MMP-1, TIMP-1 and TIMP-2 in UCA slices were measured by immunoenzymatic method (ELISA). MMP-1 activity in the arterial wall was measured using a collagenase-1-specific substrate. Results: Western immunoblot analyses detected MMP-1, TIMP-1 and TIMP-2 in the incubation fluids and in extracts from the UCA wall. Both 43- and 55-kDa (a zymogen) bands of MMP-1 were visible. The control UC serum stimulated both the amount as well as actual and potential activities of MMP-1 in the arterial wall in a time-dependent manner. In contrast to controls, the preeclamptic serum did not exert such an effect. Conclusions: The small amount and low activity of MMP-1 accompanied by elevated amounts of TIMPs (especially TIMP-1) decelerate the degradation and enhance the accumulation of collagen in the preeclamptic UCA wall.

The extracellular matrix components are differentially distributed among various structures of the umbilical cord. Wharton's jelly is especially rich in collagens and growth factors. Cathepsin B is a major cysteine protease involved in collagen degradation, as well as in the activation of precursor forms of other collagenolytic enzymes and growth factors. We assessed the activity and expression of cathepsin B in the umbilical cord arteries, veins and Wharton's jelly. Extracts of separated umbilical cord components were subjected to an activity assay with the use of specific fluorogenic substrate. The expression of cathepsin B protein was qualitatively evaluated by Western immunoblotting and quantitatively determined with an immunoenzymatic method. The total cathepsin B activity and content calculated per gram of DNA were higher in Wharton's jelly than in the umbilical cord vessels, and the latter parameter was the lowest in the umbilical cord arteries. Moreover, the expression and the activity of latent cathepsin B (following activation by pepsin digestion) calculated per gram of DNA were the highest in Wharton's jelly and the lowest in the umbilical cord arteries. High expression and activity of latent, pepsin-activatable cathepsin B related to DNA content in Wharton's jelly seem to reflect the stimulation of its cells by high amounts of collagen I and growth factors.

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Objective: The role of proteoglycans (PGs) of the umbilical cord arteries (UCAs) in the pathomechanism of pre-eclampsia is not known. Therefore we decided to compare the PGs of normal (control) UCAs and those of newborns delivered by mothers with pre-eclampsia. Methods: PGs were extracted in dissociative conditions, purified by Q-Sepharose anion exchange chromatography and lyophilized. They were analyzed by gel filtration and SDS-PAGE before and after treatment with chondroitinase ABC. Results: It was found that the PG preparation from pre-eclamptic UCAs had a higher amount of sulphated glycosaminoglycans (in relation to protein) than in the case of control UCAs. The predominant PG fraction included small PGs with core proteins of 45 and 47 kD, immunologically related to biglycan (45 kD) and decorin (45 and 47 kD). The expression of decorin core proteins was increased and that of biglycan slightly decreased in pre-eclamptic UCAs. Some other putative small PG core proteins (56, 53, 49, 42, 38 and 34 kD) were also found. They were present in higher amounts in pre-eclamptic UCAs. Larger PGs (core proteins of 99–110 and >150 kD), were detected in lower amounts, both in control and particularly in pre-eclamptic material. Conclusion: Pre-eclampsia is associated with alterations in PG composition of the UCAs. They may affect the mechanical properties of this organ and disturb fetal blood circulation.