B. C. Adelmann-Grill

ORIGIN OF CERVICAL COLLAGENASE DURING PARTURITION

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.

Biochemical changes in human cervical connective tissue after intracervical application of prostaglandin E2.

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.

Collagenase activity in the cervix of non-pregnant and pregnant women.

SummaryCervical 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 helical125I-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.

Collagen degradation in the pregnant human cervix at term and after prostaglandin-induced cervical ripening

SummaryThe 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.

Collagenase activity in the human cervix uteri after prostaglandin E2 application during the first trimester.

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.

Enzymatic collagen degradation in the pregnant guinea pig cervix during physiological maturation of the cervix and after local application of prostaglandins

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.

Physikalische, morphologische und biochemische Untersuchungen zur prostaglandin-induzierten Zervixrei-fung im 1. Trimenon

Zum praoperativen Zervixpriming im 1. Trimenon wurde das uterusselektive PGE2-Analogon Sulproston bisher fast ausschlieslich intramural-zervikal sowie intramuskular appliziert (Ubersicht bei Schmidt-Gollwitzer u. Schmidt-Gollwit-zer 1981); allerdings schrankt eine hohe Rate unerwunschter Begleitwirkungen die Akzeptanz dieser Methoden erheblich ein. Erste vielversprechende Ansatze fur eine Verbesserung des Verfahrens ergaben sich mit der intrazervikalen Applikation von Sulproston, gelost in einem viskosen Tragermedium (Rath et al. 1983, 1985).

Origin of cervical collagenase during parturition

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.

Die Bedeutung der polymorphkernigen Leukozyten für den zervikalen Reifungsprozeß unter der Geburt

Das Kollagen bildet das wichtigste Strukturprotein der Cervix uteri. Zu 70% besteht es aus Kollagen Typ I und zu 30% aus Kollagen Typ III. Im Verlaufe der Schwangerschaft kommt es zwar zu einer Zunahme des Gesamtkollagengehaltes in der Cervix uteri, der relative Anteil bezogen auf das Trockengewicht nimmt jedoch ab. Wahrend im I. und II. Trimenon elektronenmikroskopisch die Kollagenfibrillen ein geordnetes Netzwerk darstellen, kommt es nach Prostaglandin-einwirkung unter der Geburt zu einer Dissoziation und Rarefizierung der Kollagenfibrillen. Dies wird von zahlreichen Autoren als Ausdruck einer sub partu einsetzenden Kollagenolyse interpretiert. Wenn auch von Ito und anderen Autoren der Nachweis zervikaler Kollagenasen erbracht wurde, konnten bisher jedoch keine aktiven Kollagenasen in der Cervix uteri wahrend des zervikalen Reifungsbzw. Dilatationsprozesses nachgewiesen werden. Wir haben daher zervikale Proben unter standardisierten Bedingungen von der hinteren Muttermundslippe bei 6 Uhr mit einem Feuchtgewicht von 50–200 mg entnommen. Die Proben entstammten der Pramenopause, dem I. Trimester sowie dem III. Trimenon ohne Wehentatigkeit bei unreifen Zervixverhaltnissen und elektiver Sectio caesarea bei Beckenendlage. Des weiteren wurden Proben bei einer Muttermundsweite von 2–3 cm, 6–8 cm unmittelbar post partum entnommen. Hierbei konnte gegenuber dem III. Trimenon sub partu bei einer Muttermundsweite von 6–8 cm ein signifikanter Anstieg der Kollagenaseaktivitat nachgewiesen werden (p < 0,05).