Higher Content but No Specific Activity in Gelatinase B (MMP-9) Compared with Gelatinase A (MMP-2) in Human Renal Carcinoma

Gelatinases belong to a group of enzymes known as matrix metalloproteinases (MMPs). Gelatinases A and B (MMP-2 and MMP-9, respectively) are the enzymes with the highest ability to destroy collagen, primarily type IV collagen, which is an essential component of the base membrane. Hence, it can be assumed that they are involved, among other things, with the metastasis process of cancer. As a result, the objective of this study was to assess the presence, activity, and expression of selected gelatinases in human renal cancer. Healthy (n = 20) and clear-cell kidney cancer tissue samples (G2 n = 10, G3 n = 10) were analyzed. The presence and content of MMPs were measured using the Western blot and ELISA methods, respectively. The activity (actual and specific) was analyzed with a fluorimetric method. The presence of both investigated enzymes was demonstrated in the representative zymogram. MMP-9 showed the most intensive saturation. It has been observed that both gelatinases occur primarily in high molecular complexes in the human kidney, regardless of whether it is a control or tumor tissue. Both gelatinases were present in comparable amounts in healthy tissues of the kidney. MMP-9 showed a higher content than MMP-2 in both renal cancer grades, but we observed the enhanced activity of both gelatinases with an increase in the grade of renal cancer. A higher MMP-9 content and, on the other hand, lower specific activity in the cancer tissue suggest that MMP-9 is predominantly present in an inactive form in renal cancer. The higher activity of MMP-9 demonstrated using the zymography method may be a cause of different values of activity that depend on the phase of the carcinogenic process. The present study revealed changes in the tested gelatinases in healthy and cancerous tissues of renal cell carcinoma. Therefore, it can be concluded that matrix metalloproteinases 2 and 9 are enzymes directly involved in carcinogenesis, and hence, it seems that MMPs may have potential in the diagnosis and treatment of renal carcinoma.

Higher Content but Not Activity of Stromelysin-2 (MMP-10) in Comparison to Stromelysin-1 (MMP-3) in Human Renal Carcinoma

Stromelysin-1 and stromelysin-2 (matrix metalloproteinase 3; MMP-3 and matrix metalloproteinase 10; MMP-10, respectively) are enzymes that activate other metalloproteinases. Apart from collagen, they also degrade elastin, fibronectin, gelatin and laminin. In carcinogenic processes, they are involved in angiogenesis and metastasis. Therefore, the aim of this study was to evaluate the DNA content, expression and activity of both stromelysines in cancers of human kidney. Renal carcinoma tissue samples were analyzed. Low- and high-grade cancer tissues were collected. Control material was collected from part of the kidney opposite to the tumor. DNA content, stromelysines content and stromelysin-1 and stromelysin-2 activity were measured using ELISA and Western blot methods. A higher content of deoxyribonucleic acid in low- and high-grade cancer tissues in comparison to the respective control tissue was observed. Both stromelysines were presented in control and cancer tissues in high-molecular-weight complexes. The content of MMP-10 was significantly higher in comparison to MMP-3 in all investigated tissues. Moreover, the content of stromelysin-2 was significantly higher in high-grade (G3) tissues compared to grade 2 (G2) kidney cancer. A significant decrease in the actual and specific activities of both stromelysines was observed with the increase in renal cancer grade. The presented results may indicate that the degradation of extracellular matrix increases with a higher grade of cancer. Moreover, the elevated content and decreased specific activity of stromelysin-2 in cancer tissue indicate that MMP-10 is mainly present in an inactive form in renal carcinoma. Detailed knowledge of the mechanism and participation of stromelysines in extracellular matrix degradation may be important in understanding the pathomechanism of renal cancer development. Therefore, the potential application of stromelysines in the monitoring or prognosis of kidney cancer should be discussed.

Dominative role of MMP-14 over MMP-15 in human urinary bladder carcinoma on the basis of its enhanced specific activity

BACKGROUND

Human urinary bladder cancer is one of the most common cancers worldwide with the mortality rate of approximately 165,000 people annually. The modulation of extracellular matrix is a crucial event in the metastatic spread, among others in angiogenesis. It is initiated and prolonged by the cascade of matrix metalloproteinases. MMP-14 and MMP-15 are associated with a high degree of malignancy, aggressiveness, and survival prognosis by the activation of other matrix metalloproteinases (MMPs). This study was aimed at evaluating the expression and the activity of selected transmembrane metalloproteinases at different stages of human urinary bladder cancer.

METHODS

Western blot and enzyme linked immunosorbent assay (ELISA) method were used to evaluate the expression and content of MMPs and TIMP-1. The activity of studied enzymes was determined with fluorometric method.

RESULTS

Both transmembrane metalloproteinases are found in healthy or cancerous tissue in high molecular complexes of human urinary bladder. MMP-14 dominates over MMP-15, particularly in high-grade urinary bladder cancer. Their contents significantly change with the grade of bladder tumor. The amount of MMP-14 increases with increasing grade of tumor. MMP-15 content decreases in high-grade bladder cancer. With increasing grade of urinary bladder cancer their actual activity (per kg of total protein content) is varying in different ways. In all examined tissues, the specific activity of MMP-15 (per kg of the enzyme content) is much higher in comparison to MMP-14. Human urinary bladder cancer contains higher TIMP-1 amounts than control tissue but with the decrease with an increase in tumor grade.

CONCLUSION

Comparison of investigated enzymes' activity and the inhibitor content suggests it opposite effects, higher suppression of MMP-14 than MMP-15 activity in low-grade bladder cancer and reverse TIMP-1 action in high-grade cancer. The MMP-14 activity determination in urinary bladder cancer tissue may be used as a predictor of a risk of metastasis.

Peptide growth factors and their receptors in the vein wall

The varicose vein wall remodeling is a very complex process, which is controlled by numerous factors, including peptide growth factors. The aim of the study was to assess a/b FGF, IGF-1, TGF-β1, VEGF-A and their receptors in the vein wall. Varicose vein samples were taken from 24 patients undergoing varicose vein surgery. The control material consisted of vein specimens collected from 12 patients with chronic limb ischemia. Contents of aFGF, bFGF, IGF-I, TGF-β1, VEGF, IGF-1R, VEGF R1 and VEGF R2 were assessed with ELISA method. Protein expression of FGF R1 and TGF-β RII were evaluated with western blot. Increased contents of aFGF, IGF-1 and VEGF-A were found in varicose veins in comparison with normal ones (p<0.05). In contrast, a significant decrease in TGF-β content was demonstrated in varicose veins (p<0.05). Furthermore, there was no difference in bFGF content in both groups (p>0.05). IGF-1 R content was significantly increased in varicose veins (p<0.05). There was no difference in VEGF R1 content between varicose and normal veins (p>0.05), whereas VEGF R2 content was significantly increased in varicose veins (p<0.05). Western blot demonstrated increased expression of TGF-β RII in varicose veins (p<0.05) and similar expression of FGF R1 in both groups (p>0.05). Demonstrated changes in peptide growth factors and their receptors may disturb metabolism of extracellular matrix in the varicose vein wall and contribute to the development of the disease to its more advanced stages.

Suppressed Expression but Not Activity of Collagenases MMP-1 and MMP-13 in Human Renal Carcinoma

BACKGROUND

Collagenases are enzymes starting collagen degradation. The role of collagenases in renal carcinoma development is not well understood.

OBJECTIVE

Evaluation of collagen content and collagenase expression and activity in human kidney cancers.

METHODS

Collagen content was measured by the hydroxyproline assay. The expression and the content of collagenases were evaluated by Western blotting and ELISA. Fluorogenic substrate was used to measure enzyme activity.

RESULTS

Collagen content significantly decreases with the progression of kidney cancer. Both collagenases are first present in high molecular complexes in both control and cancer tissue. The healthy part of the kidney contains similar amounts of both collagenases. Collagenase content decreased significantly in tumor tissue with increasing cancer stage. MMP-13 activity is much higher than that of MMP-1 in all tissues investigated. We observed increasing collagenase activity (MMP-1 and MMP-13) with increasing renal cancer grade.

CONCLUSIONS

The lower content and higher activity of the collagenases investigated in cancer tissue indicate that most of these enzymes are in active form in renal carcinoma. The lower collagen content in cancer tissue can be explained at least in part by increased collagenase activity.

MT1-MMP evaluation in neointimal hyperplasia in the late follow-up after prosthesis implantation

Vascular surgical interventions are often burdened with late complications, including thrombosis or restenosis. The latter is generally caused by neointimal hyperplasia. Although extracellular matrix (ECM) remodelling is an important part of neointima formation, this process is not clearly understood. The aim of the study was to assess the content and activity of membrane-type 1 matrix metalloproteinase in human neointima in the late stages of its development. Matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase-2 were also evaluated. The research was performed on neointima samples collected during secondary vascular interventions from patients with chronic limb ischaemia who developed vascular occlusion at 6-18 months after aorto/ilio-femoral bypass grafting. The control material consisted of segments of femoral arteries collected from organ donors. Western blot and/or ELISA were used for the determination of MT1-MMP and TIMP-2 expression. The activity of MT1-MMP was measured by fluorometric assay and that of MMP-2 by zymography. We demonstrated significantly increased MT1-MMP protein content in neointima when compared to normal arteries. However, the activity of MT1-MMP was significantly lower in neointima than in control samples. The decreased MT1-MMP activity was concomitant with reduced activity of MMP-2. The TIMP-2 protein levels in neointima and normal arteries were not significantly different. The results of our study suggest that the reduced activity of MT1-MMP and consequently MMP-2 in human neointima may play a role in decreased degradation of ECM components and thus promote neointimal overgrowth.

A New Analytical Method for Determination of Cathepsin L Based on the Surface Plasmon Resonance Imaging Biosensor

The purpose of this study was to develop a new method for a determination of the cathepsin L—biosensor based on the Surface Plasmon Resonance Imaging technique. The cathepsin L is an endopeptidase, which degrades proteins and plays an important role in various processes occurring in the human body. The detection technique, Surface Plasmon Resonance Imaging, is an optical, label-free technique, which can be used for quantitative determination of the different proteins. In order to bind the enzyme, the cathepsin L inhibitor—RKLLW-NH₂ was used. The validation process showed that parameters: precision, accuracy, and selectivity of the method were acceptable. The analytically useful range of the standard curve was 0.50 ng/mL—15.00 ng/mL. The detection and quantification limit of method was 1.67 pg/mL and 5.07 pg/mL, respectively. The usefulness of the developed method was confirmed by the determination of the cathepsin L concentration in the blood plasma of some healthy persons and in the blood plasma of patients. The obtained results were compared with the results obtained by the ELISA. It was found that the correlation between these two methods was very strong, what suggest that the developed method can be used as the competitive method to the ELISA.

Divergent changes in the content and activity of MMP-26 and TIMP-4 in human umbilical cord tissues associated with preeclampsia

OBJECTIVES

Preeclampsia is the most common disorder associated with pregnancy. Our earlier findings revealed a substantial increase in the amount of matrix metalloproteinase-26 (matrilysin 2; MMP-26) in preeclamptic umbilical cord blood. The role of MMP-26 in preeclamptic umbilical cord tissue has not been fully elucidated. Some reports have indicated that the expression of matrilysin 2 and tissue inhibitor of matrix metalloproteinase 4 (TIMP-4) is coordinately regulated during progression of various diseases.

STUDY DESIGN

Therefore, we decided to assess the expression and activity of MMP-26 and TIMP-4 in normal and preeclamptic umbilical cord tissues - umbilical cord arteries (UCA), vein (UCV) and Wharton's jelly (WJ). Tissues obtained from 10 normal (control material) and 10 preeclamptic umbilical cords were assessed using immunoenzymatic assay, Western immunoblotting, reverse transcriptase - polymerase chain reaction and fluorometric determination of the enzyme activity.

RESULTS

All umbilical cord tissues, both control and preeclamptic, expressed MMP-26 and TIMP-4 in macromolecular complexes. Preeclampsia induced a significant increase in the content and actual activity of MMP-26 in UCV and WJ, as compared to control. The content of TIMP-4 in preeclamptic UCV and WJ was reduced. The content of MMP-26 mRNA was lower in UCA and UCV, whereas higher in WJ in preeclampsia.

CONCLUSIONS

Divergent changes in MMP-26 mRNA and protein expression suggest a difference in the factors controlling the matrilysin synthesis in healthy and preeclamptic subjects. The decrease in TIMP-4 content in preeclamptic UCV might be the main reason for significantly higher actual activity of MMP-26 in that tissue. Only in preeclamptic Wharton's jelly the changes were compatible in terms of the content and activity of MMP-26 and TIMP-4. It cannot be excluded that similar alterations can be observed for the whole vascular system of newborns delivered by mothers with preeclampsia.

SPR imaging biosensor for the quantitation of fibronectin concentration in blood samples

The purpose of this study was presentation of a new biosensor capable of determination of fibronectin. This biosensor was based on the specific interaction of anti-fibronectin antibody produced in rabbit with fibronectin. The surface plasmon resonance imaging (SPRI) technique was used as a detecting method. Optimization and characterization properties of the biosensor were studied. The determination of fibronectin concentration in natural samples was done. The results were compared with a reference method (Enzyme-Linked Immunosorbent Assay-ELISA). The analytically useful dynamic response range of biosensor is between 5 and 400ngmL^-1. The detection limit is 1.5ngmL^-1 and limit quantification is 5ngmL^-1. The proposed SPRI biosensor showed good selectivity for potential interferences. It was applied to determine fibronectin concentrations in plasma of healthy donors and of patients after thermal injury. Good correlations between results obtained using the SPRI biosensor and ELISA test (correlation coefficients for healthy donors 0.996, for patients 0.984) were obtained. The average fibronectin concentration of healthy donors was 140.5±24.6μgmL ^-1 and the average fibronectin concentration of patients was 601.5±72.1μgmL ^-1, which was in agreement with results obtained by other investigators. The obtained results indicate that the developed biosensor may be a candidate for monitoring fibronectin concentration in blood samples.

Distribution of cathepsin L in human umbilical cord tissues

The extracellular matrix components show specific distribution patterns within various structures of the umbilical cord, among which Wharton's jelly is especially collagen-rich tissue. Cathepsin L is a potent cysteine protease engaged in degradation of extracellular matrix proteins, including collagens. We evaluated the activity and expression of cathepsin L, and the inhibitory effect of cysteine protease inhibitors in the umbilical cord arteries, vein and Wharton's jelly. Cathepsin L activity and anti-papain inhibitory effect of cysteine protease inhibitors were quantified in extracts of separated umbilical cord tissues using fluorogenic substrates. The results were calculated per DNA content. The enzyme expression was assessed by Western immunoblotting. The active cathepsin L activity (without activation by pepsin digestion), its percentage in the total activity (after pepsin activation), and the expression of the mature single-chain enzyme were the lowest in the umbilical cord arteries and the highest in Wharton's jelly. The effect of cysteine protease inhibitors showed similar distribution as in the case of the active enzyme, being the highest in Wharton's jelly. Distribution of the activity and expression of mature cathepsin L within the umbilical cord probably results from distinctions in the proenzyme activation process. Differences in the action of cysteine protease inhibitors can partly restrict divergences in the enzyme activity that could reflect its expression alone. Differential enzyme action seems to contribute to tissue-specific collagen turnover within the umbilical cord cells, especially those of Wharton's jelly.

SPR imaging biosensor for determination of laminin-5 as a potential cancer marker in biological material

A new method for the selective determination of laminin-5 concentration using a biosensor and surface plasmon resonance imaging (SPRI) technique is presented. A biosensor based on the specific interaction of laminin-5 with rabbit polyclonal antibody was constructed. The analytically useful dynamic response range of the biosensor is between 0.014 and 0.1 ng mL(-1). The detection limit is 4 pg mL(-1). The potential influence of interferences on the SPRI signal was investigated, and the high selectivity of the biosensor was confirmed. In order to demonstrate the potential application of the biosensor, laminin-5 concentration in blood plasma was determined. The results were compared with the laminin-5 concentration obtained by the commercial enzyme-linked immunosorbent assay (ELISA) kit. A comparison of results from healthy donors obtained by SPRI measurement and ELISA indicates that they are close and shows good agreement with the data reported in the literature. The plasma samples of bladder cancer patients gave higher concentration measured with specific biosensor than by ELISA assay. The study shows the clear difference in concentration of laminin-5 in healthy humans and patients with bladder cancer. Extensive clinical studies using the newly developed method can result in an increase in the use of laminin-5 as a potential cancer marker.

Differential distribution of cathepsin B in human umbilical cord tissues

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.

Extracellular matrix remodeling of the umbilical cord in pre-eclampsia as a risk factor for fetal hypertension

The human umbilical cord forms a connection between the placenta and the foetus. It is composed of two arteries and one vein surrounded by Wharton's jelly. Pre-eclampsia is accompanied by extensive remodeling of extracellular matrix of umbilical cord. Matrix metalloproteinases (MMPs) are engaged in degradation of extracellular matrix proteins and activation/inactivation of certain cytokines and enzymes. These enzymes will probably play a central role in the release of matrix-embedded cytokines and growth factors. MMP-2 (gelatinase A) is the main collagenolytic enzyme of both umbilical artery and vein. Other metalloproteinases are present in several times lower amounts. Reduced activity of collagen-degrading enzymes may be a factor, which enhances the accumulation of collagen and some other proteins in the pre-eclamptic umbilical cord tissues. It seems to be possible that similar alterations occur in other fetal blood vessels. It may result in an increase in peripheral resistance as well as an increase in the blood pressure in the fetal vascular system. Some observations suggest that the raised pressure may persist after birth. Pre-eclampsia may be a factor that evokes an initiation of hypertension in utero and its amplification through childhood and adulthood.

Matrix metalloproteinases, MMP-7 and MMP-26, in plasma and serum of control and preeclamptic umbilical cord blood

OBJECTIVE

Our previous paper demonstrated that preeclampsia-associated accumulation of collagen and proteoglycans in the umbilical cord tissues is a result of increased biosynthesis and decreased degradation of these components. Metalloproteinases (MMPs) are enzymes engaged in degradation of collagen and protein cores of proteoglycans, including those which bind peptide growth factors. Some MMPs, among them matrilysins MMP-7 and MMP-26, participate in activation other members of the MMP family.

STUDY DESIGN

Studies were performed on the umbilical cord blood taken from 10 control (healthy) newborns and 10 newborns of preeclamptic women. We used Western immunoblotting, immunoenzymatic assay (ELISA) and zymography techniques for detection of matrilysins. The results were submitted to Student's t-test and Mann-Whitney test.

RESULTS

Umbilical cord blood plasma and serum of control and preeclamptic newborns contained MMP-7 and MMP-26. Both enzymes existed in the form of complexes with other extracellular matrix components and/or their tissue inhibitors in control and preeclamptic subjects. Free latent forms of both matrilysins were observed after the action of reducing agent. Furthermore, we found a distinct increase in the amount of MMP-26 in preeclamptic umbilical cord (UC) blood. No significant differences in MMP-7 content and activity in control and preeclamptic UC blood were observed.

CONCLUSIONS

MMP-7 and MMP-26 could activate MMP-9 by cleavage of some sites in pro-MMP-9. Our results suggest that the high activity of MMP-9 participates in a proteolytic release of peptide growth factors from their complexes with extracellular matrix components, which facilitate their interaction with membrane receptors and stimulate cell division and extracellular matrix synthesis in these cells. It may be one of the mechanisms of extracellular matrix remodelling in the umbilical cord of preeclamptic newborns.

Lipid compounds of human Wharton's jelly and their alterations in preeclampsia

Wharton's jelly is a myxomatous substance which surrounds the umbilical cord vessels protecting them against extension, bending, twisting and compression. Very low number of cells in this tissue produce high amounts of extracellular matrix; collagen, hyaluronate and proteoglycans which bind large quantities of peptide growth factors (PGFs). Preeclampsia (the most common pregnancy-associated syndrome) is accompanied by a significant reduction in hyaluronate and a concomitant increase in sulphated glycosaminoglycans/proteoglycans content in Wharton's jelly. Such a phenomenon corresponds to an 'early ageing' of this tissue. We have evaluated the lipid composition of Wharton's jelly and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed. It was found that Wharton's jelly contains free fatty acids (FFA), mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature is the presence of relatively high amounts of unsaturated fatty acids, including those (C18:2 and C18:3) which are nutritionally essential. Preeclampsia is associated with a slight increase in the total fatty acid content in Wharton's jelly and with marked changes in the proportional relationships between various lipids. A distinct decrease in the amounts of FFA was observed with a concomitant increase in monoacylglycerols and cholesterol esters. At least in some cases the effects exerted by PGFs are mediated by the lipid second messengers. Thus it is possible that alterations in lipid compounds of Wharton's jelly may participate in the deregulation of various cell functions, including overproduction of sulphated glycosaminoglycans or down-regulation of enzymes which participate in their degradation.

Separation and Determination of Fatty Acids from Lipid Fractions by High-Performance Liquid Chromatography: Cholesterol Esters of Umbilical Cord Arteries

Preeclampsia is accompanied by an extensive remodeling of the extracellular matrix of umbilical cord. It is associated with an increase in collagen content in the umbilical cord artery. Furthermore, preeclampsia distinctly reduces proteolytic and gelatinolytic activity, especially after activation with various agents.

We decided to develop a method for separation and determination of fatty acids from different tissues by high-performance liquid chromatography. That method allowed us to determine cholesteryl ester composition and content in umbilical cord arteries. Studies were performed on the umbilical cord arteries taken from 10 newborns delivered by healthy mothers and 10 newborns delivered by mothers with preeclampsia. Cholesteryl esters were isolated by thin layer chromatography. Fatty acids were liberated by basic hydrolysis and analyzed by HPLC of their p-bromophenacyl derivatives using detection at 254 nm. It was found that saturated fatty acids were the main group of fatty acids incorporated to cholesteryl esters in all control and preeclamptic umbilical cord arteries. Preeclampsia caused a significant increase in cholesteryl ester content in the umbilical cord arteries. An increase of neutral lipid content in vessel walls of newborns delivered by mothers with preeclampsia may be one of the factors that evoke the initiation of hypertension in utero and its amplification throughout childhood and adult life. The described method reduces time and cost consumption and allows us to determine almost all fatty acids forming cholesteryl esters contained in the tissue sample.

Lipid compounds of the umbilical cord vein and their alterations in preeclampsia

The lipid composition of vascular walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord vein and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the umbilical cord vein wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature is the presence of high amounts of monounsaturated fatty acids, mainly myristoleic acid (C14:1) and oleic acid (C18:1), and polyunsaturated fatty acids, including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with an increase in the accumulation of free fatty acids, acylglycerols and cholesterol esters in the umbilical cord vein wall, with a proportional reduction in unsaturated fatty acid contents in all the investigated lipid fractions. Total amount of myristoleate was similar to control values. It is suggested that stimulation of lipolysis in maternal tissues increases supply of free fatty acids to foetal blood and promotes the accumulation fatty acids and their esters in some foetal vascular walls.

Gelatinase matrix metalloproteinase (MMP)-2 and MMP-9 of the umbilical cord blood in preeclampsia

BACKGROUND

Preeclampsia is associated with accumulation of collagen and proteoglycans in the umbilical cord tissues as a result of increased biosynthesis and decreased degradation of these components. Matrix metalloproteinases (MMPs) are enzymes engaged in the degradation of collagen and the protein core structures of proteoglycans, including those which bind peptide growth factors.

METHODS

We used Western immunoblots, immunoenzymatic assay (ELISA) and zymography techniques for the detection of gelatinases and their inhibitors.

RESULTS

We found that both umbilical cord blood plasma and serum of controls and preeclamptic newborns contained MMP-2 and MMP-9, as well tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2. The umbilical cord plasma of preeclamptic subjects contained large amounts of MMP-9 in a form of complexes with other plasma components, and zymographic analysis demonstrated increased gelatinolytic activity at a position corresponding to MMP-9, compared to control samples. By contrast, MMP-2, TIMP-1 and TIMP-2 data showed no significant differences between preeclamptic and control samples.

CONCLUSIONS

The high activity of MMP-9 in preeclamptic plasma suggests its participation in the proteolytic release of peptide growth factors from their complexes with other matrix components, with subsequent stimulation of cell division and matrix biosynthesis. We suggest this might represent one of the mechanisms for matrix remodeling in the umbilical cord of preeclamptic newborns.

Fatty acid composition of triacylglycerols from Wharton's jelly determined by high-performance liquid chromatography

The improved method for HPLC determination of fatty acids was proposed. The chromatographic separation of p-bromophenacyl derivatives of fatty acids under a gradient elution was achieved at 40 degrees C with an RP-18 LiChroCART 5 column and organic mobile phase containing methanol, acetonitrile, water and TEAP buffer pH 5.6. The quantitative determination of those derivatives was performed at 254 nm. Preeclampsia, the most common pregnancy complication, did not affect triacylglycerol content in the umbilical cord Wharton's jelly in comparison to the control material. However, it changed the composition of fatty acids, bound to that lipid class. The method allows the determination of almost all fatty acids forming the investigated neutral lipid class, contained in a solid tissue sample. The use of TEAP buffer excluded precipitation and flow stoppage in the HPLC system. The method reduced time and costs and might be useful for all other lipid classes and different tissues.

Pre-eclampsia-associated alterations in decorin, biglycan and versican of the umbilical cord vein wall

OBJECTIVE

The role of proteoglycans in the rearrangement of the extracellular matrix of the umbilical cord vein wall in pre-eclampsia is not known. Decorin, biglycan and versican are the main proteoglycans of the umbilical cord vein wall. We decided to test whether the amounts of these proteoglycans alter in pre-eclampsia.

STUDY DESIGN

Study was performed on the umbilical cord veins taken from 10 newborns delivered by healthy mothers (control group) and from 10 newborns delivered by mothers with pre-eclampsia. Proteoglycans were extracted in dissociative conditions, purified by Q-Sepharose anion exchange chromatography and lyophilised. Decorin, biglycan and versican were analysed by SDS-PAGE followed by Western blotting before and after treatment with chondroitinase ABC. The amounts of decorin, biglycan and versican core proteins were assessed by ELISA method.

RESULTS

We found that both control and pre-eclamptic umbilical cord vein wall contained all the three proteoglycans. ELISA assay showed the amounts of the core proteins of decorin, biglycan and versican were distinctly higher in pre-eclamptic material in comparison to control vessel. Western blotting confirmed that the expression of all these proteoglycan core proteins increased in pre-eclampsia. They featured in the same electrophoretic mobility-45 and 47 kDa for decorin, 45 kDa for biglycan, and 300 and 320 kDa for versican.

CONCLUSION

The content of decorin, biglycan and versican in the umbilical cord vein wall is elevated in pre-eclampsia in comparison to the corresponding control vessel. These alterations may affect the mechanical properties of this vessel and disturb foetal blood circulation.

The inhibitory effect of preeclamptic umbilical cord blood serum on matrix metalloproteinase-1 in arterial slices incubated in vitro

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.

Preeclampsia-associated reduction of cathepsin D activity in the umbilical cord

BACKGROUND

Preeclampsia is accompanied by an increase of collagen contents in the umbilical cord (UC) arteries and in Wharton's jelly. Cathepsin D is one of the enzymes which participates in collagen degradation and activates precursor forms of collagenolytic metalloproteinases. It was decided to evaluate the activity of cathepsin D within umbilical cord arteries, veins and Wharton's jelly and its alterations in preeclampsia.

MATERIALS AND METHODS

Umbilical cord components were separated and submitted to homogenisation/extraction with 0.05 M Tris-HCl+0.2% Triton X-100, pH 7.5. Proteolytic activities of the extracts were studied with a use of cathepsin D-specific substrate. Western immunoblot technique was employed to detect this enzyme.

RESULTS

It was found that human umbilical cord tissues contain both active and inactive forms of cathepsin D. Preeclampsia is associated with a distinct increase in the amount of this enzyme in the umbilical cord, whereas its activity deeply decreased. Activation with trypsin augments cathepsin D activity in preeclamptic umbilical cord to the values observed in control arteries or even exceeds the control values (veins, Wharton's jelly).

CONCLUSIONS

Preeclampsia is associated with a reduction in the activity of cathepsin D in human umbilical cord. The low activity of cathepsin D may reduce collagen degradation and enhance its accumulation in the umbilical cord, especially in the arteries. Similar changes in other foetal blood vessels may result in an increase of vascular resistance and hypertension, which may persist after birth.

Collagen of umbilical cord vein and its alterations in pre-eclampsia

The state of the vascular system of the mother and of placenta is known to exert a great influence on intrauterinal development of the fetus. Pre-eclampsia is the most common pathological syndrome connected with pregnancy. Since collagen is one of the main constituents of the vessel wall a comparison was made with collagen content and its molecular polymorphism in umbilical cord veins of newborns from healthy and pre-eclamptic mothers. It was found that umbilical cord veins of newborns from mothers with pre-eclampsia contained 18% less collagen than those of the newborns from normal pregnancies. This decrease was accompanied by a slight decrease of collagen solubility, but all its types (I, II, IV, V and VI) were present. However, the umbilical vein wall of newborns from mothers with pre-eclampsia contained relatively less of type I and more of type III collagen than the normal umbilical cord. These differences may be connected with a disturbance of blood flow in fetus of a woman with pre-eclampsia.

[Extracellular matrix of the umbilical cord vein in EPH gestosis and fibroblast growth factor]

It was found in our previous studies that EPH gestosis is accompanied by an extensive remodeling of the extracellular matrix of the umbilical cord. Studies were performed on the umbilical cord veins of 10 control and 10 newborns delivered by mothers with EPH gestosis. It was decided to determine umbilical cord vein ability to bind of labeled (125J)-basic fibroblast growth factor (bFGF), and FGF content by Western immunoblot and ELISA methods. Our experiments indicated that the extracts of umbilical cord vein contain endogenous bFGF and several soluble FGF-binding compounds of different molecular weight. It is of interest that EPH gestosis is associated with a decrease in bFGF content. It seems be possible that the decrease of bFGF amount may be one of the factors, which constrain the biosynthesis of collagen in EPH gestosis umbilical cord vein wall.

Pre-eclampsia (EPH-gestosis)-induced decrease of MMP-s content in the umbilical cord artery

BACKGROUND

It was found in our previous paper that pre-eclampsia-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.

METHODS

For this reason it was decided to evaluate the effect of pre-eclampsia on the content and activity of metalloproteinases by immunoenzymatic method (ELISA), zymographic technique and with the use of specific substrates.

RESULTS

A low amount of MMP-1 (collagenase 1), MMP-9 (gelatinase B) and MMP-3 (stromelysin 1) was detected in the extracts from the wall of the umbilical cord artery. MMP-2 (gelatinase A) is the main collagenolytic enzyme in UCA wall (both latent and active form). Pre-eclampsia is associated with a distinct reduction in those metalloproteinases content in comparison to control UCAs. It can be concluded from zymography that MMP-2 (gelatinase A) of the umbilical cord artery forms an inactive complex with a tissue inhibitor of metalloproteinases (TIMP). Such a complex dissociates under the action of p-aminophenylmercuric acetate (APMA) or sodium dodecyl sulphate.

CONCLUSIONS

The decrease of metalloproteinases content and activity in the umbilical cord artery may be a factor that reduces the breakdown of collagen in the arterial wall and promotes the accumulation of this protein. The accumulation of collagen with simultaneous reduction in elastin content in the UCA may be the factor that reduces the elasticity of arterial wall and decreases the blood flow in the fetus of women with pre-eclampsia.

The effect of pre-eclamptic umbilical cord serum on fibroblast division in culture

Edema, proteinuria, hypertension (EPH-gestosis), most commonly termed as pre-eclampsia, is the most common pregnancy-associated pathological syndrome. It is accompanied by a thorough remodelling of extracellular matrix in the umbilical cord tissues. It is commonly known that the presence of serum in culture medium strongly stimulates many functions of cells cultured in vitro. It was decided to check how the pre-eclamptic serum affects the fibroblast division in culture. Ki-67 is a protein present in proliferating cells and can be detected during all phases of the cell cycle (G1, S, G2/M) but not in resting (G0) cells. PCNA (proliferating cell nuclear antigen) is an intranuclear polypeptide whose synthesis rate is at its maximum during the S-phase of the cell cycle. The expression of Ki-67 and PCNA was measured by immunocytochemical methods and biosynthesis of DNA was evaluated by [14C]-thymidine incorporation. The activity of pre-eclamptic umbilical cord serum (UC-serum) was found to be distinctly lower in comparison to control one. The expression of Ki and PCNA in fibroblast cultures treated with pre-eclamptic serum was also distinctly lower. Also the incorporation of [14C]-thymidine to DNA was lower than in the cultures treated with control UC-serum. It may by concluded that pre-eclampsia reduces the mitogenic activity of the umbilical cord serum.

Collagen of umbilical cord vein and its alterations in pre-eclampsia

The state of the vascular system of the mother and of placenta is known to exert a great influence on intrauterinal development of the fetus. Pre-eclampsia is the most common pathological syndrome connected with pregnancy. Since collagen is one of the main constituents of the vessel wall a comparison was made with collagen content and its molecular polymorphism in umbilical cord veins of newborns from healthy and pre-eclamptic mothers. It was found that umbilical cord veins of newborns from mothers with pre-eclampsia contained 18% less collagen than those of the newborns from normal pregnancies. This decrease was accompanied by a slight decrease of collagen solubility, but all its types (I, II, IV, V and VI) were present. However, the umbilical vein wall of newborns from mothers with pre-eclampsia contained relatively less of type I and more of type III collagen than the normal umbilical cord. These differences may be connected with a disturbance of blood flow in fetus of a woman with pre-eclampsia.

Preeclampsia-associated decrease of potential collagenolytic and gelatinolytic activities in the wall of the umbilical cord vein

Preeclampsia is the most common pathological syndrome associated with pregnancy. It is accompanied by remodelling of the extracellular matrix of the umbilical cord. A decrease of collagen content in the umbilical cord vein was described. This decrease may result from reduced collagen biosynthesis or enhanced collagen degradation. It was decided to evaluate whether or not this phenomenon is associated with alterations in the activities of collagenolytic, gelatinolytic and non-specific proteolytic enzymes that may be involved in collagen degradation, as well as the activity of prolidase which provides proline as a substrate for collagen biosynthesis. Studies were performed on the umbilical cord veins of newborns delivered by healthy mothers and those with preeclampsia. The control vein extract, activated with trypsin, degraded reconstituted collagen fibres (64.4+/-2.9 nmol Hyp x mg(-1) protein), whereas the preeclamptic material demonstrated only a trace activity. The venous wall extract contained a latent form of gelatinase that might have been activated by trypsin and 4-aminophenylmercuric acetate. A decrease in the gelatinolytic and proteolytic activities of preeclamptic vein extract at neutral pH was found. Prolidase activity was almost 3-fold lower in the preeclamptic extract (240.6+/-29.3 nmol Pro x min(-1) x mg(-1) protein) in comparison to the control (608.2+/-63.7 nmol Pro x min(-1) x mg(-1)protein). It was concluded that the umbilical cord vein contains a latent form of gelatinase A. The decrease in prolidase activity may reduce collagen biosynthesis, resulting in a decrease of this protein in the preeclamptic umbilical cord vein.

Stimulation of glycosaminoglycan biosynthesis by umbilical cord serum of newborns delivered by mothers with EPH gestosis (preeclampsia)

OBJECTIVE

Edema, proteinuria, hypertension (EPH) gestosis, also known as preeclampsia, is the most common, pregnancy-associated pathological syndrome. It is accompanied by a significant increase in collagen content in the umbilical cord arteries and early replacement of hyaluronic acid by sulfated glycosaminoglycans (GAGs) both in these arteries and in Wharton's jelly. Such a remodelling of the umbilical cord tissues is accompanied by an increase in insulin-like growth factor-I (IGF-I) concentration in the umbilical cord serum.

METHODS

Contact-inhibited human fibroblasts were incubated in Dulbecco culture medium containing control or EPH umbilical cord serum and supplemented with (14)C-glucosamine or (35)S-sulfate. Radioactive GAGs were isolated, submitted to electrophoretic fractionation and quantified.

RESULTS

The presence of umbilical cord serum in culture medium strongly stimulated the incorporation of (14)C-glucosamine and (35)S-sulfate into GAGs synthesized by these cells. EPH serum was much more active in stimulation of sulfated GAGs biosynthesis than control serum, whereas the biosynthesis of hyaluronic acid was stimulated by both sera to a similar degree.

CONCLUSION

Since IGF-I is known as a stimulator of collagen and sulfated GAG biosynthesis, the high concentration of this growth factor in the umbilical cord plasma may be responsible for preeclampsia-associated remodeling of the umbilical cord.

Extracellular matrix components of the wall of umbilical cord vein and their alterations in pre-eclampsia

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.

[Selected aspects of proteolytic activity of umbilical cord and its alterations in EPH-gestosis]

EPH-gestosis is accompanied by an extensive remodelling of the extracellular matrix of the umbilical cord arteries, vein and Wharton's jelly. For better understanding of processes proceeding in it we decided to determine proteolytic activity in acidic pH range. Presented results suggest that cathepsin D is one of the main proteolytic enzymes of umbilical cord.

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

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.

[The activities of some glycosaminoglycan degrading enzymes in the wall of the umbilical cord vein and their alteration in EPH-gestosis]

EPH-gestosis evokes great connective tissue rebuilding in the wall of umbilical cord arteries and Wharton's jelly. Not much is known about umbilical cord vein maintenance. For better understanding of processes proceeding in it we decided to determine activities of some glycosaminoglycan-degrading enzymes. It was found that specific activities of some neutral endoglycosidases and exoglycosidases decreased during EPH-gestosis. Acidic endoglycosidases and sulphatases specific activities did not change. Those results with no changes in content and proportional relationship of umbilical cord vein glycosaminoglycans suggest that EPH-gestosis disturbs markedly those connective tissue element metabolism.

Activities of some glycosaminoglycan- degrading enzymes in Wharton's jelly and their alteration in EPH-gestosis (Pre-eclampsia)

Oedema, proteinuria, hypertension (EPH)-gestosis (pre-eclampsia) is associated with a premature replacement of hyaluronic acid by sulphated glycosaminoglycans (GAGs), both in the umbilical cord arteries and in Wharton's jelly. It may be concluded from our previous report that such a phenomenon may be the result of reduction in degradation of these compounds. In order to support such a conclusion the activities of GAG-degrading enzymes in normal umbilical cord arteries and those taken from newborns delivered by mothers with EPH-gestosis were compared. It was found that EPH-gestosis results in a significant reduction in the activities of neutral endoglycosidases degrading most of the sulphated GAGs (except keratan sulphate). In the case of acidic endoglycosidases, no characteristic alterations have been found. Only the activity of heparan sulphate-degrading endoglycosidase significantly decreased. In contrast to the above-mentioned endoglycosidases, the activities of arylsulphatase B and 6-sulphatase distinctly increased. The decrease in the activities of endoglycosidases are thought to be responsible for EPH-gestosis-associated accumulation of sulphated GAGs in extracellular matrix of Wharton's jelly. This leads to the suspicion that EPH-gestosis-induced changes in the GAGs composition may alter the fibrillogenesis conditions in Wharton's jelly. The sulphated GAGs accumulated in Wharton's jelly may interact with some growth factors which modify the myofibroblasts' proliferation, gene expression, protein biosynthesis and other processes. A significance of EPH-gestosis-induced alteration in Wharton's jelly is discussed.

The activities of some glycosaminoglycan-degrading enzymes in the wall of the umbilical cord artery and their alteration in edema, proteinuria, hypertension (EPH)-gestosis

Edema, proteinuria, hypertension (EPH)-gestosis is associated with a premature replacement of hyaluronic acid by sulphated glycosaminoglycans (GAGs), both in the umbilical cord arteries (UCAs) and in Wharton's jelly. This phenomenon may be considered as a sign of premature ageing of the umbilical cord tissues. The decrease in hyaluronic acid content in the UCA was found to be the result of reduced biosynthesis of this substance, whereas an increase in sulphated GAGs-content is rather a result of slower degradation of newly synthesised GAGs. In this study the activities of GAGs-degrading enzymes in normal umbilical cord arteries and those taken from newborns delivered by mothers with EPH-gestosis were compared. It was found that EPH-gestosis results in a significant reduction in the activities of neutral endoglycosidases degrading most of the sulphated glycosaminoglycans (with the exception of heparan sulphate). The activities of exoglycosidases also decrease but to a lesser degree. These alterations are thought to be responsible for EPH-gestosis-associated accumulation of sulphated glycosaminoglycans in the extracellular matrix of the arterial wall. Such remodelling of the arterial wall may affect foetal blood circulation. The significance of these phenomena in the pathological mechanism of EPH-gestosis is discussed.

Electrophoretic and chromatographic patterns of glycosaminoglycans of the umbilical cord vessels and their alteration in EPH-gestosis

It was found that hyaluronic acid is the most abundant glycosaminoglycan (GAG) both in the umbilical cord arteries and in the umbilical cord veins. Chromatographic and as well as electrophoretic studies demonstrated that EPH-gestosis (Edema-Proteinuria-Hypertension), the most common pathological syndrome occurring in pregnancy, is accompanied by premature replacement of hyaluronic acid by sulphated GAGs in the investigated arteries but not in the veins. Such a replacement is a characteristic feature of the ageing process. One may conclude that EPH-gestosis is associated with a "premature ageing" of the umbilical cord arterial walls. The mechanism and possible role of this phenomenon in pathology are discussed.

Electrophoretic and chromatographic patterns of glycosaminoglycans of the umbilical cord vessels and their alteration in EPH-gestosis

It was found that hyaluronic acid is the most abundant glycosaminoglycan (GAG) both in the umbilical cord arteries and in the umbilical cord veins. Chromatographic and as well as electrophoretic studies demonstrated that EPH-gestosis (Edema-Proteinuria-Hypertension), the most common pathological syndrome occurring in pregnancy, is accompanied by premature replacement of hyaluronic acid by sulphated GAGs in the investigated arteries but not in the veins. Such a replacement is a characteristic feature of the ageing process. One may conclude that EPH-gestosis is associated with a "premature ageing" of the umbilical cord arterial walls. The mechanism and possible role of this phenomenon in pathology are discussed.

Glycosaminoglycan-biosynthesis in the wall of the umbilical cord artery and its alteration in EPH-gestosis

The mechanism of edema, proteinuria, hypertension (EPH)-gestosis-associated premature replacement of hyaluronic acid by sulphated glycosaminoglycans (GAGs) in the umbilical cord arteries is not known. It may result from altered biosynthesis, a different degradation rate or a combination of both phenomena. In order to solve this problem, it was decided to evaluate the biosynthesis and degradation of newly synthesized GAGs in the umbilical cord arteries of control newborns and those delivered by mothers with EPH-gestosis. Incorporation of radioactive precursors ([14C]glucosamine and [35S]sulphate) into GAGs and degradation of newly synthesized GAGs using the pulse-chase experiment were evaluated. We found that the investigated tissue slices incorporated distinctly less [14C]glucosamine into hyaluronic acid in comparison to controls. In contrast to that, the biosynthesis of sulphated GAGs did not change significantly. However, the degradation of newly synthesized sulphated GAGs was distinctly slower than in control tissues. It may be concluded that an EPH-gestosis associated decrease in hyaluronic acid content in the umbilical cord artery is a result of decreased biosynthesis of this substance, whereas an increase in sulphated GAGs-content is rather a result of slower degradation of newly synthesized GAGs.

Collagen and glycosaminoglycans of Wharton's jelly and their alterations in EPH-gestosis

Some prenatal pathological processes may be caused by biochemical and morphological alterations in the umbilical cord (UC). EPH-gestosis is the most common pregnancy-associated pathological process. For these reasons the role of collagen and glycos-aminoglycans (GAGs) of UC in pathobiochemistry of this syndrome seems to be important. We studied histology of extracellular matrix components, quantity, solubility and molecular polymorphism of collagen, proportional relationships between various types of collagen, the amounts of GAGs and proportional relationships between them in Wharton's jelly of control newborns delivered by healthy mothers and those delivered by mothers with EPH-gestosis. We found that Wharton's jelly is abundant in collagen and GAGs. This collagen is very insoluble and resistant to the action of depolymerizing agents (4% EDTA-Na2, pepsin). Types I, III and V collagens were isolated and quantified. Hyaluronic acid constitutes about 70%, whereas sulphated GAGs constitute about 30% of total GAGs. EPH-gestosis is accompanied by significant increase in sulphated GAGs: hyaluronic acid ratio. The EPH-gestosis-associated alterations in Wharton's jelly correspond to 'premature ageing' of this tissue.

Collagen of umbilical cord arteries and its alterations in EPH-gestosis

We decided to investigate the EPH-gestosis--connected alterations in collagen of the umbilical cord arteries. The samples of arterial walls were submitted to histological and biochemical studies. It was found that umbilical cord arteries taken from newborns of mothers with EPH-gestosis contain more than twice the amount of collagen in comparison to corresponding arteries of newborns from normal pregnancies. An increase of collagen content in these vessels in accompanied by a slight decrease of its solubility. Types I, III, IV, V and VI collagens were found both in normal umbilical cord arteries and in those of newborns delivered by mothers with EPH-gestosis but their proportional relationships were different. EPH-gestosis is accompanied by an increase of a proportional amount of type III-collagen and a decrease of type I collagen in umbilical cord arteries. It seems that these changes in the umbilical cord arteries may be responsible for the decrease of blood flow in fetus of woman with EPH-gestosis.