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In specimens taken from the posterior lip of the cervix uteri we determined the collagenase activity and the glycosaminoglycan concentration. In biopsies obtained from the lower uterine segment during cesarian section we measured cytokines (IL-8, IL-2, TNF alpha) and matrix metalloproteinases (MMP-8, MMP-9). We found that the release of collagenases is critically involved in the process of cervical dilatation. The glycosaminoglycan concentration increases during pregnancy and shows remarkable changes of the distribution patterns of the different glycosaminoglycans. The parturition is characterized by a dramatic loss of most of the glycosaminoglycans. Furthermore, the IL-8 shows a close correlation to the clinical feature of cervical ripening and is closely associated with the release of MMP-8 and MMP-9. Summarizing the process of cervical maturation and dilatation is a complex enzymatic controlled process with substantial remodelling of the cervical extracellular matrix. The cytokines IL-8 seems to play an essential role in triggering the process of cervical dilatation. more...

The central function of the cervix to maintain pregnancy is biochemically characterized by an increased synthesis of collagen, proteins, glycosaminoglycans (GAG) and fibronectin within the extracellular matrix, thus leading to an increase of cervical volume without significant changes of cervical consistency. During the time of cervical ripening we found a marked reduction of collagen concentration, a 2.5-fold increase in GAG content, a significant fall in dermatan sulfate concentrations from 41% to 15% of total GAG content, a 12-fold increase in hyaluronate concentrations, and a marked reduction in fibronectin, demonstrated by immunhistochemical methods. Thus, the loss of collagen and sulfated GAGs may facilitate distensibility in the ripened cervix, while the significant gain in hyaluronate associated with hydratation may explain the soft and swollen consistency. In this connection increased hyaluronate concentrations and degradation of fibronectin may play a trigger role for subsequent cervical dilatation. The dramatic changes of the cervix during parturition occurring within a few hours require the rapid activation and action of catabolic enzyme systems. Our studies showed a significant increase of sialidase-, collagenase- and elastase activities during cervical dilatation. These proteinases originate from polymorphonuclear leucocytes (pml), which accumulate in cervical capillaries at the onset of labor; this is followed by a massive leucocyte infiltration of the cervical stroma at the beginning of cervical dilatation and a degranulation of the pml at further dilatation, thus releasing collagenase and other proteinases. This process is limited by the immediate post partum insudation of the cervix by plasma containing highly potent proteinase inhibitors. The clinical aim of our basic biochemical studies is to develop new concepts in the causal treatment of cervical pathology during pregnancy. more...

Cervical biopsies were taken during the first trimester from primigravidae and plurigravidae at different time points after intracervical application of prostaglandin E2-gel. Collagenase activity was determined by a highly specific technique using native, triple helical collagen as substrate. Elastase-alpha 1-proteinase-inhibitor complex (elastase) was measured by a commercially available assay, and glycosaminoglycan (GAG) analyses were performed as described by Greiling et al. (5, 6). The maximum activity of collagenase was found 2 hours after PGE2 application in plurigravidae and 4 hours after application in primigravidae. Elastase activity rose nearly 7-fold to maximum values 4 hours after PGE2 application. The total GAG concentrations and the dermatan sulfate concentrations increased by approximately 10%, while the hyaluronic acid concentrations were found to be elevated significantly by nearly 50% in the PGE2-primed cervices. We conclude that a time-dependent enzymatic collagen degradation by collagenases and other proteinases and an increase in hyaluronic acid concentrations are the significant biochemical events underlying PG-induced cervical ripening. more...

Cervical biopsy specimens were obtained under standard conditions from the posterior lip of the uterine cervix in 105 patients. A significant increase of collagenase activity was observed during parturition as determined with an assay with iodine 125-labeled native triple-helical collagen type I as the substrate. The collagenase was not likely to originate from cervical fibroblasts because in situ hybridization failed to detect synthesis of the specific procollagenase messenger ribonucleic acid. However, migration of polymorphonuclear leukocytes into the cervical stroma occurred on onset of labor, and an antibody specific for human leukocyte collagenase that did not cross react with fibroblast collagenase revealed the presence of the enzyme in the granules of polymorphonuclear leukocytes and subsequently in the extracellular matrix of the cervix. Therefore it is likely that the cells critically involved in collagen degradation during cervical dilatation are not resident fibroblasts but rather polymorphonuclear leukocytes emigrating from blood vessels. more...

Cervix biopsies were obtained during the first trimester from plurigravidae and primigravidae at various times after intracervical application of prostaglandin E2. The tissues were extracted with Ca(2+)-containing buffer, and collagenase activity was determined in these extracts using a solid phase assay in which triple helical 125I-labelled collagen was cleaved. Collagenase was detected in all samples but elevated activity was present only during a short temporal window after prostaglandin application. Maximal activity was observed 1 and 2 h after application of prostaglandin in multigravidae and 4 h in primigravidae. These data can explain why collagenase activity in cervical tissues after prostaglandin application had previously not been found. They indicate somewhat different mechanisms of cervical ripening in primigravide compared to multigravidae. more...

Maturation of the cervix during pregnancy is an essential pre-requisite for an uncomplicated delivery at term. Physiological cervical ripening is characterised by a diffuse loosening of the collagenous connective tissue with widely scattered collagen fibrils and an increased amount of extracellular ground substance. These morphological changes are similar to those after prostaglandin (PG)-pre-treatment of the cervix. The local application of PG leads to a marked mulifocal loosening of the collagen fibre bundles with "activated" fibroblasts, characterised by a fine granular loosening of the cytoplasm, vacuolised enlarged mitochondria and an increased number of cytoplasmatic vesicles close to the cell surface. In the course of pregnancy the volume of the cervix increases by a significant rise in synthesis of collagen, protein, glycosaminoglycan and fibronectin. The change in consistency during late pregnancy corresponds to a significant decrease in dermatan sulphate coninciding with a marked increase in hyaluronic acid concentration associated with increased water uptake. Contrary to the already published literature, enzymatic collagen degradation does not play an important role in physiological cervical maturation. The action of catabolic enzymes (collagenases, glycosidases), liberated from polymorphonuclear leukocytes invading the extracellular matrix, is responsible for the rapid dilatation of the cervix at parturition. This process is limited by the immediate postpartum insudation of the cervix by plasma containing highly potent proteinase inhibitors (e.g. alpha 2-macroglobulin). PG-induced cervical ripening is associated with a time-limited enzymatic collagen degradation, an increased synthesis of non-collagenous proteins and a significant increase in hyaluronic acid concentration. Our basic biochemical findings in cervical ripening and dilatation during parturition may greatly contribute to the development of new concepts in the causal treatment of cervical pathology during pregnancy. more...

Cervical biopsies were obtained from non pregnant patients and from pregnant at various stages of gestation and during labour. The tissues were extract with a Ca(++)-containing buffer, and collagenase activity was determined in these extracts using a solid phase assay in which triple helical 125I-labelled collagen was cleaved. Collagenase was detected in all samples but significantly elevated activity was only present in labour at 6-8 cm cervical dilatation. This provides direct evidence for the crucial role of specific collagen degradation during cervical ripening and dilatation. more...

Collagen degradation has been suggested to play an important role in the process of cervical ripening at term. After giving informed consent tissue samples were taken from the posterior lip of 10 non-pregnant women of child-bearing age, 10 women having a termination of pregnancy at 9-12 weeks' gestation and 12 women who had had normal spontaneous deliveries at term. Collagenase activity was measured by a specific technique using native, triple helical collagen. Proteolytic activity was determined with commercially available 14C-methaemoglobin as substrate. For identification of collagen fragments SDS-polyacrylamid-gel-electrophoresis was performed using a modified Laemmli-technique. Collagenase and protease activity were found in all extracts of the different groups. There was a marked increase in enzymatic activities in the postpartum tissue samples suggesting that significant collagen breakdown had taken place. The absence of typical collagen fragments in the SDS-electrophoresis seemed to be due to a very rapid further degradation of the fragments by proteases into small peptides which then readily left the cervix. The present findings confirm the essential role of proteolytic enzymes in cervical dilatation at term. more...

For examination by electron microscopy tissue samples were taken from the posterior lip of the cervix of 8 patients having a termination of pregnancy at 9-12th week gestation and 16 patients of comparable gestational age who had an intracervical application of either 2 ml 5% tylose or 50 micrograms sulprostone-tylose gel 8 hours before biopsy. The efficacy of cervical priming was demonstrated objectively by tonometric studies. In addition, collagenase and protease activities were determined in the cervical tissue extracts of the different treatment groups. For identification of typical collagen fragments SDS-polyacrylamide-gel-electrophoresis were carried out on the acetic acid soluble extracts. The local application of sulprostone gel induced a marked multifocal loosening of the collagenous framework; there was no evidence for leucocyte infiltration or necrosis caused by the prostaglandin (PG) pretreatment. In the areas of disorganized collagen fibres cervical fibroblasts seemed to be activated characterized by fine granular loosening of the cytoplasma, dilated cisternae of rough endoplasmatic reticulum, vacuolized enlarged mitochondria and an increased number of cytoplasmatic vesicles close to the cell surface. Collagenase and protease activities were found in all extracts of the different treatment groups, however, PG-application led to no significant increase in enzymatic activities. There was no evidence for the presence of typical collagen cleavage products in the SDS-electrophoresis. Contradictory to the hitherto published literature enzymatic collagen degradation does not play an essential role in PG-induced cervical ripening. more...

The role of enzymatic collagen degradation in prostaglandin-induced and physiological cervical ripening was studied in guinea pigs. The cervices were removed from (a) 8 non-pregnant guinea pigs, (b) 8 animals at day 45 of pregnancy, (c) 14 pregnant animals of comparable gestational age which had either an intracervical application of 0.2 ml 5% tylose or 10 micrograms sulprostone gel, and (d) 8 guinea pigs at day 63 to 65 of pregnancy. Collagenase activity was assayed in a highly specific and sensitive system using native collagen type I as substrate. Protease activity was measured by the method of Green and Shaw. Collagen fragments were identified by SDS-polyacrylamide electrophoresis (SDS-PAGE) of acetic-soluble fractions. Collagenase and protease activities were found in all extracts from the different groups. However, there were no differences in enzymatic activities between the non-pregnant, early-pregnant and late-pregnant cervical specimens. Prostaglandin pre-treatment of the cervix led to no significant increase in either collagenase or protease activity as compared to the control groups. The absence of typical collagen degradation products in the SDS-PAGE suggested that no significant collagen breakdown had taken place. In contrast to previously published literature, we conclude that enzymatic collagen degradation is unlikely to be a key factor in prostaglandin-induced and physiological cervical ripening. more...

The role of enzymatic collagen degradation in prostaglandin-induced and physiological cervical ripening was studied by determining collagenase and other proteolytic activity in extracts of cervical biopsies. Collagenase activity was assayed in a highly specific and sensitive system using native collagen type I as substrate. The intracervical application of sulprostone gel prior to termination of 1st trimester pregnancy led to a marked improvement in cervical dilatability. Collagenase and proteolytic activity were found to be significantly higher in postpartum samples than in specimens obtained from the nonpregnant or early pregnant cervix. After sulprostone treatment enzymatic activities were only marginally elevated. Analysis of extractable peptides showed that sub partu collagen was degraded in preference to noncollagenous proteins into very small fragments, whereas in the process of prostaglandin-induced cervical ripening collagen degradation appears to be of minor importance. more...

Tissue samples were taken from the posterior lip of the cervix of 10 non-pregnant women, 10 women having a termination of pregnancy at 9-12 weeks' gestation and 16 women having a termination who had had an intracervical application of either 50 micrograms sulprostone gel or 2 ml 5% tylose 8-12 hours previously. The efficacy of cervical priming was demonstrated objectively by tonometric measurements. Collagenase activity was determined by a new highly specific technique using native, triple helical collagen. Protease activity was measured by a modified Anson-test. For identification of collagen fragments SDS-polyacrylamide electrophoresis was done on the acetic acid soluble fractions. The sulprostone gel induced effective cervical ripening in all of the patients. Collagenase and protease activity were found in all extracts from the different groups, however, PG-pretreatment of the cervix led to no significant increase in enzymatic activities. In addition, the absence of typical collagen cleavage products in the SDS-electrophoresis suggested that no significant collagen breakdown had occurred. In contrast to previously published literature we conclude that enzymatic collagen degradation does not play a predominant role in PG-induced cervical ripening. more...