Human recombinant interleukin-1 alpha increases biosynthesis of collagenase and hyaluronic acid in cultured human chorionic cells

Matrix metalloproteinases in preterm prelabor rupture of membranes in the setting of chorioamnionitis: A scoping review

Fetal or gestational membranes extend from the placenta to enclose the fetus and amniotic fluid. While the membranes spontaneously rupture at term in normal pregnancies, they can rupture prematurely before the onset of labor, termed preterm prelabor rupture of membranes (PPROM). PPROM can be triggered by bacterial infection or sterile inflammation in the membranes, known as chorioamnionitis (CAM). The membranes derive their tensile strength from a collagen-rich extracellular matrix (ECM); as such, understanding the enzymes and processes that can degrade the membrane ECM are of paramount importance. Matrix metalloproteinases (MMPs) are a class of enzymes capable of degrading collagen and other components of the ECM, and can be induced by inflammation. We used a scoping review to address the question of how MMP activity is associated with PPROM, particularly their induction due to sterile or nonsterile CAM. We have found that the most studied MMPs in PPROM were MMPs 2, 8, and 9. Additionally, some MMPs are constitutively active, while others are induced by inflammation. Mechanistic studies of the pathways that induce MMP activation are sparse, and this area is ripe for future studies. Targeting MMP activation could be a future strategy to delay or prevent PPROM.

The Role of Danger Associated Molecular Patterns in Human Fetal Membrane Weakening

The idea that cellular stress (including that precipitated by stretch), plays a significant role in the mechanisms initiating parturition, has gained considerable traction over the last decade. One key consequence of this cellular stress is the increased production of Danger Associated Molecular Patterns (DAMPs). This diverse family of molecules are known to initiate inflammation through their interaction with Pattern Recognition Receptors (PRRs) including, Toll-like receptors (TLRs). TLRs are the key innate immune system surveillance receptors that detect Pathogen Associated Molecular Patterns (PAMPs) during bacterial and viral infection. This is also seen during Chorioamnionitis. The activation of TLR commonly results in the activation of the pro-inflammatory transcription factor Nuclear Factor Kappa-B (NF-kB) and the downstream production of pro-inflammatory cytokines. It is thought that in the human fetal membranes both DAMPs and PAMPs are able, perhaps via their interaction with PRRs and the induction of their downstream inflammatory cascades, to lead to both tissue remodeling and weakening. Due to the high incidence of infection-driven Pre-Term Birth (PTB), including those that have preterm Premature Rupture of the Membranes (pPROM), the role of TLR in fetal membranes with Chorioamnionitis has been the subject of considerable study. Most of the work in this field has focused on the effect of PAMPs on whole pieces of fetal membrane and the resultant inflammatory cascade. This is important to understand, in order to develop novel prevention, detection, and therapeutic approaches, which aim to reduce the high number of mothers suffering from infection driven PTB, including those with pPROM. Studying the role of sterile inflammation driven by these endogenous ligands (DAMPs) activating PRRs system in the mesenchymal and epithelial cells in the amnion is important. These cells are key for the maintenance of the integrity and strength of the human fetal membranes. This review aims to (1) summarize the knowledge to date pertinent to the role of DAMPs and PRRs in fetal membrane weakening and (2) discuss the clinical potential brought by a better understanding of these pathways by pathway manipulation strategies.

Production and Regulation of Matrix Metalloproteinases and Their Inhibitors by Human Peritoneal Mesothelial Cells

Objective

Human peritoneal mesothelial cells (HPMC) are likely to be involved in maintenance of the peritoneal membrane. We determined whether these cells were able to synthesize the matrix degrading enzymes, matrix metalloproteinases (MMPs), likely to be responsible for the breakdown of this membrane, and whether this secretion could be modulated by cytokines involved in the inflammatory response.

Design

MMP activity in conditioned medium of growth-arrested HPMC was measured by zymography. Cultures were incubated in the presence and absence of the cytokines transforming growth factor-beta (TGFβ) and interleukin (IL)-1β in order to determine the effects of these cytokines on this process. The mRNA for these MMPs, together with that of their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs), was also examined by reverse transcriptase polymerase chain reaction (RT-PCR).

Results

HPMC were shown to constitutively secrete the metalloproteinases MMP-2 and MMP-3 in vitro. In response to the proinflammatory cytokine IL-1β, the protein and mRNA for MMP-9 was induced, while secretion of MMP-2 was unaltered. Similarly, the mRNA for MMP-3 was also increased relative to actin following the addition of IL-1β. TGFβ was shown to slightly induce the secretion of MMP-2 together with the mRNA for TIMP I, TIMP II, and, to a greater extent, TIMP III. Used peritoneal dialysate was also shown to induce MMP-9 secretion, and this effect was blocked by the co-incubation of IL-1 receptor antagonist. The secretion of enzyme activity was shown to be from the apical surface of the cells.

Conclusion

HPMC have the ability to control the accumulation of extracellular matrix by secreting the matrix degrading molecules MMP-2, MMP-3, and MMP-9. In addition, the secretion of these enzymes, together with that of their inhibitors (TIMPs) is regulated by the cytokines IL-1β and TGFβ. This process is likely to be important in both the normal maintenance of the integrity of the peritoneal membrane and in the changes that occur following prolonged peritoneal dialysis.

The Role of Matrix Degrading Enzymes and Apoptosis in Repture of Membranes

Prematurity is the third leading cause of perinatal death, and preterm premature rupture of the membranes (pPROM) is associated with approximately 20-50% of all preterm births. The etiologic factors described for pPROM and preterm labor (PTL) are the same, although the clinical presentation (pPROM vs PTL) differs among patients. The reason for this disparity is unknown and poses a therapeutic dilemma. Several etiologic factors have been described for PTL and pPROM. PTL and pPROM are associated with overwhelming host inflammatory response. Many of these pro-inflammatory factors (inflammatory cytokine release) are common in both conditions; however, the clinical presentation differs. The objective of this review is to explain the differential expression pattern of matrix metalloproteinases (MMPs) and pro-apoptotic elements in human fetal membranes in pPROM and PTL and how they interact to present different clinical outcomes during pregnancy.

Possible roles of proinflammatory and chemoattractive cytokines produced by human fetal membrane cells in the pathology of adverse pregnancy outcomes associated with influenza virus infection

Pregnant women are at an increased risk of influenza-associated adverse outcomes, such as premature delivery, based on data from the latest pandemic with a novel influenza A (H1N1) virus in 2009-2010. It has been suggested that the transplacental transmission of influenza viruses is rarely detected in humans. A series of our study has demonstrated that influenza virus infection induced apoptosis in primary cultured human fetal membrane chorion cells, from which a factor with monocyte differentiation-inducing (MDI) activity was secreted. Proinflammatory cytokines, such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-β, were identified as a member of the MDI factor. Influenza virus infection induced the mRNA expression of not only the proinflammatory cytokines but also chemoattractive cytokines, such as monocyte chemoattractant protein (MCP)-1, regulated on activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1β, IL-8, growth-regulated oncogene (GRO)-α, GRO-β, epithelial cell-derived neutrophil-activating protein (ENA)-78, and interferon inducible protein (IP)-10 in cultured chorion cells. These cytokines are postulated to associate with human parturition. This paper, therefore, reviews (1) lessons from pandemic H1N1 2009 in pregnancy, (2) production of proinflammatory and chemoattractive cytokines by human fetal membranes and their functions in gestational tissues, and (3) possible roles of cytokines produced by human fetal membranes in the pathology of adverse pregnancy outcomes associated with influenza virus infection.

The aetiology and pathogenesis of chronic allograft nephropathy

Renal transplantation is the ultimate form of renal replacement therapy, and is the treatment of choice for many patients with end-stage renal failure. The advent of calcineurin inhibitor based immunosuppression resulted in the 1-year renal allograft failure rate dropping from around 50% twenty years ago to less than 10% in more recent times. Despite a massive improvement in renal allograft survival in the first year following transplantation 10-year graft survival can be as low as 50%. Chronic allograft nephropathy (CAN) is recognised as the main cause of renal allograft failure following the first year after transplantation. The diagnosis of CAN can only be made histologically. Typically biopsy specimens in grafts with CAN demonstrate an overall fibrotic appearance effecting the vascular endothelium, renal tubules, interstitium, and glomerulus. The risk factors for CAN are divided into alloimmune and alloimmune independent. Alloimmune dependent factors include acute cellular rejection, severity of rejection, subclinical rejection and HLA mismatch. Alloimmune independent factors such as delayed graft function, donor age, Cytomegalovirus infection, donor/recipient co-morbidity and of course calcineurin inhibitor toxicity are important in the development of CAN. The pathogenesis of CAN is complex, multifactorial, and unfortunately incompletely understood. There are a number of pivotal steps in the initiation and propagation of the fibrosis seen in biopsy specimens from kidneys with CAN. Endothelial activation in response to one or more of the aforementioned risk factors stimulates leukocyte activation and recruitment. Recruited leukocytes subsequently infiltrate through the endothelium and induce key effector cells to secrete excessive and abnormal extracellular matrix (ECM). Enhanced deposition of ECM is a histological hallmark of CAN. This paper aims to present a concise yet accurate and up-to-date review of the literature concerning the aetiological factors and pathological processes which are present in the generation of CAN.

Secretion of bioactive interleukin-6 and tumor necrosis factor-alpha proteins from primary cultured human fetal membrane chorion cells infected with influenza virus

Influenza virus infection during pregnancy is implicated in one of the causes of premature delivery, abortion and stillbirth. Pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha produced by fetal membranes, are postulated to facilitate premature delivery. We investigated the secretion of IL-6 and TNF-alpha from primary cultured human fetal membrane chorion and amnion cells infected with influenza virus at protein and bioactivity levels in order to understand the pathology of premature delivery during influenza virus infection. Concentrations of IL-6 and TNF-alpha proteins were significantly increased in culture supernatants of chorion cells by influenza virus infection. Culture supernatants of the virus-infected chorion cells stimulated the proliferation of IL-6-sensitive 7-TD-1 cells and induced the cytolysis of TNF-alpha-sensitive L929 cells, both activities of which were inhibited by the addition of respective antibody, whereas no such phenomena were observed in amnion cells. The results demonstrated that only chorion cells secreted significant amounts of bioactive IL-6 and TNF-alpha proteins responding to influenza virus infection. The present study suggests a possibility that the secretion of bioactive IL-6 and TNF-alpha proteins from fetal membrane chorion cells is implicated in the pathogenesis of premature delivery during influenza virus infection.

Testing for risk of preterm delivery

Four discrete mechanisms for the pathogenesis of PTD have been described but they share a final common pathway. Moreover, although the mechanisms have distinct clinical characteristics, they are not mutually exclusive. As an example, triplet gestations are more likely to be associated with periconceptional intrauterine manipulations predisposing to infection, as well as fetal growth restriction, decidual hemorrhage, and pathologic uterine distention. An improved understanding of these pathologic pathways has led to the development of new tests to predict PTD. Use of multiple markers (eg, serum CRH, salivary E3, cervical IL-6, TAT, and fFN) holds promise for implementing targeted interventions to prevent PTD.

Cytokines, prostaglandins and parturition--a review

The elaboration of cytokines, chemokines and immunomodulatory proteins in the placenta and gestational membranes has been extensively investigated in the context of both normal and abnormal pregnancy and delivery. Patterns of expression of cytokines in the foetal membranes and decidua suggest that inflammatory activation occurs modestly with term labour, but much more robustly in preterm delivery, particularly in the presence of intrauterine infection. Enhanced chemokine expression, particularly evident in deliveries with an infected amniotic cavity, is presumably responsible for recruiting infiltrating leukocytes into the membranes thereby amplifying the inflammatory process and hastening membrane rupture and delivery. Anti-inflammatory cytokines suppress inflammatory reactions in the placenta, but under some circumstances may act in a pro-inflammatory fashion in the membranes. Intracellular signalling by cytokines is modulated by proteins such as SOCS (Silencer Of Cytokine Signalling)-1, -2 and -3. Changes in the abundance of these proteins occur with term labour, implicating them as modulators of cytokine actions around the time of parturition. Prostaglandins, released by the membranes in response to stretch and the actions of pro-inflammatory cytokines, act not only upon the myometrium and cervix, but may also exert paracrine/autocrine effects on cell viability and matrix protein integrity. The localization and regulation of prostanoid isomerases, responsible for converting PGH(2) (derived from prostaglandin H synthase-1 and -2) to bioactive prostanoids, are being studied in these tissues, particularly in the context of cytokine interactions. Although the gestational tissues are known to be sources of PGD(2), PGJ(2) and its derivatives, the regulation of production of these prostaglandins has yet to be studied in any detail and their actions, which may include apoptosis and suppression of inflammation, remain poorly defined. A more complete understanding of these aspects of cytokine-prostaglandin interactions in pregnancy and parturition will, no doubt, unfold as current studies come to fruition.

Increased levels of interleukin-6 in cervical secretions and assessment of the uterine cervix by transvaginal ultrasonography predict preterm premature rupture of the membranes

OBJECTIVE

The objective of this study was to investigate the predictive factors of premature rupture of the membranes (preterm PROM).

METHODS

The study was undertaken with cervical secretions collected from 72 consenting singleton pregnant women between 20 and 33 weeks of gestation. The levels of interleukin (IL) 1alpha, IL-1beta, IL-6, IL-8, matrix metalloproteinase (MMP) 1, MMP-2, MMP-9, tissue inhibitors of matrix metalloproteinase (TIMP) 1, TIMP-2, granulocyte elastase, and fetal fibronectin in cervical diluted specimens were measured by immunoassay, and the uterine cervix was assessed by transvaginal ultrasonography. Demographic, obstetric, clinical, neonatal, and laboratory data were analyzed by univariate analysis, multiple logistic regression, and receiver operator characteristic curve analysis.

RESULTS

Preterm PROM occurred in 6 women, and 63 women delivered at term. Multiple logistic regression analysis indicated a significant independent association with preterm PROM for the cervical IL-6 levels and cervical length. The receiver operator characteristic curve analysis revealed that an IL-6 level of >/=240 pg/ml in cervical secretions and a cervical length of </=28 mm had higher diagnostic performance in predicting preterm PROM.

CONCLUSION

It is suggested that preterm PROM is associated with increased cervical IL-6 levels and a short cervix.

Production of matrix metalloproteinase-9 in lipopolysaccharide-stimulated human amnion occurs through an autocrine and paracrine proinflammatory cytokine-dependent system

The objective of this study was to determine the presence of autocrine/paracrine regulation of matrix metalloproteinase-9 (MMP-9) expression mediated by proinflammatory cytokines in human fetal membranes. Fetal membranes obtained from women who underwent cesarean delivery before labor were manually separated into amnion and chorion layers and maintained in culture. These explants were stimulated with tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and either lipopolysaccharide (LPS) alone or LPS with anti-TNFalpha or anti-IL-1beta-neutralizing antibodies. Levels of proMMP-9 in culture media were evaluated by zymography. Enzyme-linked immunosorbant assay was performed to measure the quantity of IL-1beta, TNFalpha, and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) after LPS stimulation. ProMMP-9 activity was upregulated after stimulation of the amnion by LPS, TNFalpha, and IL-1beta. The increased activity of proMMP-9 resulting from LPS stimulation in the amnion was blocked by the addition of TNFalpha neutralizing antibody but not with anti-IL-1beta. No significant effect of LPS, TNFalpha, or IL-1beta on proMMP-9 expression was observed in the chorion; however, the chorion produced both cytokines when stimulated with LPS. In contrast, TIMP-1 levels remained unchanged in all cultures incubated in the presence of LPS. Therefore, these data indicate that proMMP-9 is produced by the amnion but not the chorion in response to LPS. Because anti-TNFalpha-neutralizing antibody inhibits proMMP-9 activity in the amnion, TNFalpha appears to upregulate proMMP-9 production by the amnion in an autocrine fashion. Meanwhile, TNFalpha and IL-1beta produced by the chorion may upregulate amnionic proMMP-9 production in a paracrine manner.

Expression of matrix metalloproteinase (MMP)-2 and MMP-9 in human placenta and fetal membranes in relation to preterm and term labor

Extensive extracellular matrix (ECM) remodeling is found in many processes during human parturition at term and preterm. These include cervical ripening, fetal membrane rupture, and placental detachment from the maternal uterus. Matrix metalloproteinases (MMPs) are the main mediators of ECM degradation. The present study was designed to investigate the expression of MMP-2 and MMP-9 in human fetal membranes (FMs) and placental (PL) tissues with or without labor at preterm and term parturition. Both zymography and Western blot analysis showed that MMP-9 was significantly (P < 0.01) increased in preterm and term labor FM, compared with nonlabor. Term labor PL also had a much higher (P < 0.05) level of MMP-9 than that of term nonlabor. No significant difference in MMP-2 expression was found between labor and nonlabor tissues. Immunolocalization studies revealed a specific distribution pattern for MMP-2 and MMP-9. MMP-2 was localized to the amnion mesenchyme, chorion laeve trophoblast, decidua parietalis, and blood vessels in PL villi. MMP-9 was localized mainly to amnion epithelia, chorion laeve trophoblast, decidua parietalis, and PL syncytiotrophoblasts. Separate cell culture from different layers of FM and culture of purified PL trophoblast cells showed that PL syncytiotrophoblast and amnion epithelial cells exclusively produced MMP-9; chorion trophoblast cells secreted both MMP-2 and MMP-9, but amnion mesenchymal cells produced only MMP-2. We concluded that MMP-2 and MMP-9 exhibited cell-specific expression in the human PL. An increase in MMP-9 expression may contribute to degradation of the ECM in the FM and PL, thereby facilitating FM rupture and PL detachment from the maternal uterus at labor, both preterm and term.

Molecular mechanisms of renal allograft fibrosis

BACKGROUND

Chronic graft nephropathy (CGN) remains the leading cause of renal allograft loss after the first year following transplantation. Histologically it is characterized by glomerulosclerosis, intimal hyperplasia and interstitial fibrosis. The pathogenesis is unclear, but is likely to involve both immunological and non-immunological factors. Despite improvements in short-term graft survival rates, new immunosuppressive regimens have made no impact on CGN.

METHODS

A review of the current literature on renal transplantation, novel immunosuppression regimens and advances in the molecular pathogenesis of renal allograft fibrosis was performed.

RESULTS AND CONCLUSION

Recent advances in understanding of the underlying molecular mechanisms involved suggest autocrine secretion of cytokines and growth factors, especially transforming growth factor beta, are associated with a change in fibroblast phenotype leading to the deposition of extracellular matrix. Repeated insults trigger upregulation of the tissue inhibitors of matrix metalloproteinases, favouring accumulation of extracellular matrix. To date, no drug has proved effective in inhibiting or reducing allograft fibrosis. The deleterious consequences of chronic immunosuppression on the development of such fibrosis are now recognized; newer immunosuppressive drugs, including rapamycin and mycophenolate mofetil, reduce profibrotic gene expression in both experimental and clinical settings, and offer potential strategies for prolonging allograft survival.

Persistent detection of alfa-fetoprotein in the vagina without overt preterm premature rupture of the membranes. Clinical and chemical characterizations

OBJECTIVES

The objectives of this study were to clinically characterize and seek risk factors for the patients with persistently detected alfa-fetoprotein (AFP) in the vagina without showing overt preterm premature rupture of the membranes (PROM).

STUDY DESIGN

The cohort study was undertaken using vaginal-cervical specimens collected consecutively between 21 and 40 weeks of gestation from 25 consenting women. Demographic, obstetric, neonatal, and laboratory data from patients with persistent positive results of AFP kit tests without showing overt leakage of amniotic fluid were compared to those from controls. Cervical levels of interleukin-1 alpha, interleukin-1 beta, interleukin-6, interleukin-8, and granulocyte elastase were measured by immunoassay, and the uterine cervix was assessed by transvaginal ultrasonography. Statistical analysis involved Fisher's exact test and Mann-Whitney U test.

RESULTS

The incidence of overt preterm PROM was significantly higher in the patients with persistently detected AFP in preterm (3 in 4 cases) than in controls (3 in 21 controls). At sampling before determination of persistently detected AFP, patients with persistently detected AFP had significantly higher cervical levels of interleukin-6 and significantly shorter cervical length than controls.

CONCLUSIONS

Patients with persistently detected AFP in the vagina without showing overt preterm PROM have the risk of overt preterm PROM. Increased levels of interleukin-6 in cervical specimens and short cervical length may be risk factors for the occurrence of persistent detection of AFP in the preterm.

Molecular epidemiology of preterm delivery: methodology and challenges

Preterm delivery (PTD) appears to be a complex trait determined by both genetic and environmental factors. Few studies have examined genetic influence on PTD. The overall goal of our study is to examine major candidate genes of PTD and to test gene-environment interactions. Our study includes 500 preterm trios, including 500 preterm babies and their parents and 500 maternal age-matched term controls. We will perform the transmission/disequilibrium test (TDT) on candidate genes thought to be important in each of the four biological pathways of PTD: (1) decidual chorioamionotic inflammation: interleukin 1 (IL-1), IL-6, and tumour necrosis factor (TNF); (2) maternal and fetal stress: corticotropin-releasing hormone (CRH); (3) uteroplacental vascular lesions: methylenetereahydrofolate reductase (MTHFR); and (4) susceptibility to environmental toxins: GSTM1, GSTT1, CYP1A1, CYP2D6, CYP2E1, NAT2, NQO1, ALDH2, and EPHX. We will also perform standard case-control analyses on the 500 preterm cases and 500 term controls to examine gene-environment interactions. The major environmental, nutritional and social factors as well as clinical variables known or suspected to be associated with PTD will be used to test for gene-environment interactions. This study integrates epidemiological and clinical data as well as genetic markers along major pathogenic pathways of PTD. The findings from this study should improve our understanding of genetic influences on PTD and gene-environment interactions.

Markers of risk for preterm delivery

Clinical and experimental evidence indicate that PTD results from four primary pathogenic mechanisms: activation of the maternal or fetal HPA axis; amniochorionic-decidual or systemic inflammation; decidual hemorrhage; and, pathologic distention of the myometrium. Each of these four pathways has a distinct epidemiological and clinical profile, and unique biochemical and biophysical pathways initiating parturition, but shares a common final biochemical pathway involving myometrial activation and stimulation, and enhanced genital tract protease activity promoting PPROM and cervical change. Traditional methods of predicting women at risk relying on obstetrical history or symptoms and epidemiological risk factors are neither sensitive nor specific. Recent approaches to predicting PTD, including sonographic measurement of cervical length and biochemical assays for hCG, cytokines, fFN, MMPs, estrogens, and CRH, are more sensitive than traditional methods. Moreover, given the heterogeneous, interactive etiopathogeneses of PTD, multiple biochemical markers should not only increase sensitivity and specificity, but also permit the detection of the relative contribution of each pathogenesis to the overall risk of PTD.

Collagenolytic enzymes (gelatinases) and their inhibitors in human amniochorionic membrane

OBJECTIVE

This study was designed to investigate the presence of matrix metalloproteinase-2 (gelatinase A), matrix metalloproteinase-9 (gelatinase B), and their natural inhibitors in both cultured amniochorionic membrane and membrane obtained from women with infection-associated preterm labor.

STUDY DESIGN

Amniochorionic membranes were collected from women with documented intraamniotic infection and from women not in labor undergoing elective repeat cesarean section with no signs of infection or other complications of pregnancy. Normal membranes were cultured and exposed to endotoxin and peptidoglycan polysaccharide. Messenger ribonucleic acid expression for gelatinase A, gelatinase B, and tissue inhibitors of matrix metalloproteinase types 1 and 2 was studied with use of reverse transcriptase-polymerase chain reaction and localization of messenger ribonucleic acid was accomplished with use of in situ hybridization. Release of gelatinases from the membranes was studied with gelatin zymography. Tissue inhibitors of matrix metalloproteinase peptides were localized with use of immunocytochemistry.

RESULTS

The expression of matrix metalloproteinase types 2 and 9 was seen in amniochorionic membranes in culture. Matrix metalloproteinase-2 was seen in membranes from nonlaboring women and in women with intraamniotic infection, whereas matrix metalloproteinase-9 was seen only in membranes from women with intraamniotic infection. The matrix metalloproteinase-9 expression could also be induced by lipopolysaccharide or peptidoglycan polysaccharide stimulation in culture. In situ hybridization localized messenger ribonucleic acid for these matrix metalloproteinases to both amnion and chorion. Zymogram studies showed the activity of matrix metalloproteinase-2 in normal resting membrane and cultured membrane. Matrix metalloproteinase-9 was induced by culture conditions. Tissue inhibitor of matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-2 messenger ribonucleic acid was seen in normal, infected, and cultured membranes. In situ hybridization data indicated that these messages were mainly produced by chorion, but they were also seen in amnion. Immunohistochemistry demonstrated the presence of tissue inhibitor of matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-2 peptides in both amnion and chorion and in cells of the reticular layer of the matrix.

CONCLUSION

Normal amniochorionic membrane is a source of matrix metalloproteinase-2 and tissue inhibitors of matrix metalloproteinases. Culture conditions and infection induce matrix metalloproteinase-9 expression and release from amniochorion. These findings suggest that these collagenolytic enzymes may play a role in premature rupture of the membranes in infection, which can lead to preterm labor.

Release of interleukin-1 beta by dermatan sulfate suppresses hepatocyte growth

Among glycosaminoglycans, dermatan sulfate (DS) is the strongest inhibitor of DNA synthesis in adult rat hepatocytes in primary culture stimulated with insulin and epidermal growth factor. Hyaluronate also inhibited DNA synthesis, whereas chondroitin-6 sulfate, 4-sulfate or heparin had no effect on DNA synthesis in hepatocytes. Analysis of growth regulatory factors in hepatocyte culture medium treated with DS revealed that interleukin-1 (IL-1) was released into the medium. IL-1 beta mRNA was detected in DS-treated hepatocytes by reverse transcriptase-polymerase chain reaction, but not in untreated hepatocytes. For a marked inhibition of DNA synthesis, more than 10 hr of exposure to DS before cultured hepatocytes started DNA synthesis, was required. Similarly, more than 10 hr was required after the addition of DS before IL-1 beta mRNA was detected. These findings suggest that DS in the medium induced the production of IL-1 beta which, in turn, reduced DNA synthesis in hepatocytes.

Expression of inflammatory cytokines (interleukin-1 beta and interleukin-6) in amniochorionic membranes

OBJECTIVE

This study was designed to investigate the expression of inflammatory cytokines (interleukin-1 beta and interleukin-6) by fetal membranes in response to infection in vivo and to endotoxin in organ culture.

STUDY DESIGN

Amniochorionic membranes were collected from infected and uninfected women and analyzed for cytokine messenger ribonucleic acid and protein. Normal membranes were cultured and exposed to endotoxin. Messenger ribonucleic acid expression was analyzed by reverse transcriptase-polymerase chain reaction. Cellular localization of messenger ribonucleic acid and protein was determined by in situ hybridization and immunocytochemical evaluation, respectively.

RESULTS

Messenger ribonucleic acid for interleukin-1 beta appeared to be increased in infected or endotoxin-stimulated amniochorionic membranes, whereas interleukin-6 messenger ribonucleic acid was only observed in infected membranes or after endotoxin stimulation. Interleukin-1 beta messenger ribonucleic acid was localized exclusively to chorionic cells, whereas protein was observed in both chorion and amnion. Interleukin-6 messenger ribonucleic acid and protein were produced in both amniotic and chorionic cells.

CONCLUSION

Amniochorionic membranes are a site of inflammatory cytokine production. These findings may have significance in preterm labor or premature rupture of membranes.

Identification and independent regulation of human mesangial cell metalloproteinases

Mesangial cells are known to secrete metalloproteinases that are capable of degrading the constituents of the GBM, and hence are potentially involved not only in the regular maintenance of the ECM components in the glomerulus, but also of contributing to any damage to these components that occurs in disease states. In this report we positively identify by Northern blotting the neutral proteinase that is constitutively secreted by the human mesangial cell (HMC) as gelatinase A (MMP2). Stimulation of HMC gelatinase by IL-1 beta or PMA causes an increase in the total amount of gelatinolytic activity secreted. On examination, however, this increased activity is shown, both by immunoreactivity and by PCR to be due to the induction of the higher molecular weight form of gelatinase, gelatinase B (MMP9), while the amount of gelatinase A remained unaffected. In addition antigen and messenger RNA have been identified for both the specific inhibitors of metalloproteinases TIMP-1 and TIMP-2. The appearance of the larger inducible gelatinase with similar substrate specificity implies that the regular turnover of matrix components may be due to the constitutively released gelatinase A while in pathological situations the inducible gelatinase B becomes predominant. The synthesis and secretion of TIMP-1 and TIMP-2 indicates that the mesangial cell is capable of controlling the activity of its own secreted enzymes.

Hyaluronate depolymerization activity induced by progesterone in cultured fibroblasts derived from human uterine cervix

High-molecular-weight [14C]hyaluronate was incubated with cultured fibroblasts from human uterine cervix and skin, and then the depolymerization of the hyaluronate was investigated. [14C]Hyaluronate in the medium of skin fibroblasts was depolymerized into a constant molecular weight (M(r) about 40,000), whereas that of cervix fibroblasts was not depolymerized, irrespective of incubation period. However, when progesterone was added to the medium of cervix fibroblasts, hyaluronate was depolymerized to the same extent as that in skin fibroblasts. The reducing terminal sugar of the depolymerized hyaluronate was N-acetylglucosamine. These results suggest that a hyaluronate-depolymerizing enzyme, endo-beta-N-acetylglucosaminidase, was induced by progesterone in cultured fibroblasts derived from human uterine cervix.

Structural characteristics of term human fetal membranes: a novel zone of extreme morphological alteration within the rupture site

OBJECTIVE

To determine the structural characteristics of the rupture site of term fetal membranes (amniochorion and decidua) that rupture spontaneously after the onset of labour.

DESIGN

Fourteen term fetal membranes were examined immediately after delivery at the light microscope level. Multiple samples were taken along the whole rupture site and long an axis between this site and placental edge. Morphometric analysis of the thickness of the constituent layers of the fetal membranes was performed.

SETTING

Leicester Royal Infirmary Maternity Hospital.

RESULTS

A restricted zone of extreme altered morphology, characterised by marked swelling and disruption of the connective tissue, thinning of the trophoblast layer and thinning or absence of decidua, was identified in the rupture site of all patients. Morphometric analysis of the thickness of membrane layers showed that these changes and the ratio between the thickness of the connective tissue layers and that of the trophoblast and decidua (termed fetal membrane morphometric index) were significant between the zone of extreme altered morphology and the rest of the membranes.

CONCLUSIONS

The morphological features of the zone of extreme altered morphology suggests that it represents an area of structural weakness of the membranes. Since this zone did not include the whole length of the rupture site, it is likely that it was present before membrane rupture and was generated during pregnancy. We hypothesise that the zone of extreme altered morphology represents the site of initial rupture after which the tear is transmitted through the membranes to produce the rupture site. It is possible that if these changes become more extreme, then prelabour membrane rupture may occur. Further characterisation of this zone may help to understand the mechanism of its genesis and its role in predisposing the fetal membranes to rupture.

Involvement of protein kinase C in the interleukin 1 alpha-induced gene expression of matrix metalloproteinases and tissue inhibitor-1 of metalloproteinases (TIMP-1) in human uterine cervical fibroblasts

The role of protein kinase C in the interleukin 1 (IL-1)-mediated production of pro-matrix metalloproteinases (proMMPs) and tissue inhibitor-1 of metalloproteinases (TIMP-1) in human uterine cervical fibro-blasts has been investigated. IL-1 and a protein kinase C activator, 12-O-tetradecanoylphorbol 13-acetate (TPA) augmented the production of proMMP-1 (interstitial procollagenase), proMMP-3 (prostromelysin-1) and TIMP-1, but their effects were inhibited by the protein kinase C inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) and staurosporine in a dose-dependent manner. The suppressive effect of H-7 and staurosporine on the IL-1-induced production of proMMPs-1 and -3 and TIMP-1 resulted from the decrease in the steady-state levels of their mRNAs. When protein kinase C was down-regulated by treating the cells with a high level of TPA, the inductive effect of IL-1 upon proMMP-3 production was reduced considerably. These results indicate that protein kinase C mediates the IL-1-induced production of proMMPs-1 and -3 and TIMP-1 at the pretranslational level in human uterine cervical fibroblasts. On the other hand, neither IL-1 nor TPA modulated the production of proMMP-2 (progelatinase A). Both IL-1 and TPA also accelerated the production of prostaglandin E2 (PGE2) by cervical fibroblasts. However, the treatment of the cells with staurosporine in the presence of IL-1 or TPA further augmented PGE2 synthesis, suggesting that the increased synthesis of PGE2 by IL-1 treatment is mediated via signalling pathways distinct from those of proMMPs-1 and -3 and TIMP-1.

The presence of cervical and vaginal fetal fibronectin predicts preterm delivery in an inner-city obstetric population

OBJECTIVE

It has previously been shown that fibronectin bearing a specific oncofetal domain is present at the chorionic-decidual interface and that its release into cervical and vaginal secretions accurately predicts preterm delivery in patients with uterine contractions. This study examines whether serial assessment of cervical and vaginal fetal fibronectin allows for the prediction of preterm delivery in symptom-free patients derived from an inner-city, general obstetric population.

STUDY DESIGN

Cervical and vaginal samples were obtained from 429 consenting patients who received routine prenatal care between 24 and 37 weeks' gestation. A sensitive immunoassay was used to quantitate cervical and vaginal fetal fibronectin levels, and clinicians were blinded to fetal fibronectin results. Post hoc receiver operating characteristic curve analysis was used to determine which sample site (cervical or vaginal), fetal fibronectin concentration, and number of consecutive positive samples optimized screening efficacy. Logistic regression was employed to determine whether fetal fibronectin was an independent predictor of preterm delivery.

RESULTS

The spontaneous preterm delivery rate was 11% (49/429). Among the 326 patients sampled within 28 days of delivery, receiver operating characteristic curve analysis indicated that the presence of a single cervical fetal fibronectin value > 60 ng/ml between 24 and 36 weeks' gestation predicted preterm delivery with a sensitivity of 73%, a specificity of 72%, and positive and negative predictive values of 25% and 95%, respectively. A vaginal fetal fibronectin value > 50 ng/ml predicted preterm delivery with a sensitivity of 68%, a specificity of 80%, and positive and negative predictive values of 30% and 95%, respectively. Cervical and vaginal fetal fibronectin predicted preterm deliveries resulting from both membrane rupture and preterm labor with intact membranes. A positive fetal fibronectin result preceded preterm delivery by 3.4 (+/- 3.2) weeks. Stepwise logistic regression demonstrated that cervical and vaginal fetal fibronectin levels were independent predictors of preterm delivery with adjusted odds ratios of 8.9 (95% confidence interval 3.6 to 22.1) and 6.0 (95% confidence interval 2.6 to 13.7), respectively.

CONCLUSIONS

Among patients undergoing monthly cervical and vaginal sampling between 24 and 36 weeks' gestation, the presence of fetal fibronectin is a sensitive and specific predictor of preterm delivery.

Biochemistry and physiology of preterm labour and delivery

Human parturition is associated with profound changes in uterine connective tissue affecting mainly the cervix, but the endocrine control of cervical ripening remains obscure. Connective tissue changes are also implicated in premature rupture of the membranes, a problem often associated with preterm delivery, and it is believed that local inflammatory infiltration may play a role in both this condition and cervical ripening, but it is difficult to define which changes precede parturition and which are a consequence of the trauma of labour. Chorioamnionitis can cause preterm labour by provoking the release of inflammatory mediators in the decidua/fetal membranes area and it is likely that activation of prostaglandin release by decidual macrophages is involved in triggering labour. However, the role of macrophages and other bone marrow derived cells in normal labour and in labour associated with chorioamnionitis needs to be defined. It is likely that treatment with a combination of antibiotics and prostaglandin synthase inhibitors and/or other anti-inflammatory drugs is the most appropriate therapeutic approach. Idiopathic preterm labour and spontaneous labour at term are probably due to changes in the sensitivity of the myometrium to endogenous agonists. Recent progress in cell signalling pathways, such as the characterization of regulatory G proteins and the cloning of hormone receptors, should clarify the mechanism of action of relaxing and contracting agents on myometrial cells and should provide the means for the development of new therapeutic agents of high effectiveness and selectivity. This approach should result in better management of both term and preterm labour.

Regulation of hyaluronate production by interleukin 1 in cultured human chorionic cells

Human chorionic cells in culture synthesized and secreted a large amount of hyaluronate as well as tissue collagenase. When these cells were treated with human recombinant interleukin 1 alpha (hrIL-1), the biosynthesis and secretion of hyaluronate were predominantly accelerated, but those of sulfated glycosaminoglycans were not modulated. This promotive effect of hrIL-1 was not due to the increase in endogenous prostaglandins including prostaglandin E2 since cyclooxygenase inhibitors, indomethacin and diclofenac did not modulate the IL-1-mediated production of hyaluronate. On the other hand, the cotreatment of chorionic cells with hrIL-1 and cycloheximide suppressed the IL-1-mediated hyaluronate production, suggesting that protein, de novo, synthesis required for the enhancement of hyaluronate synthesis. Upon treatment with hrIL-1, the membrane bound-hyaluronate synthase activity was increased up to 5-fold in a time-dependent manner. On the other hand, when chorionic cells were treated with hrIL-1 and/or protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methyl-pyperadine hydrochloride (H7), the IL-1-mediated production of hyaluronate was effectively suppressed. Similarly, H7 effectively suppressed the protein kinase activator, 12-O-tetradecanoyl-phorbol-13-acetate-enhanced production of glycosaminoglycans with a similar extent. These results indicate that IL-1-induced acceleration of hyaluronate production was reflected on the increase in hyaluronate synthase activity, and that protein kinase C participates positively in the IL-1-signal transduction for the increased synthesis of hyaluronate in human chorionic cells.

Pro-major basic protein has three types of sugar chains at the pro-portion

The amino-acid sequence of purified recombinant pro-major basic protein from Chinese hamster kidney cells was determined to verify the primary structure and glycosylation sites. Reduced and S-carboxamidemethylated protein was first digested with Achromobacter proteinase I. Each peptide was characterized by amino-acid analysis and amino-acid sequence analysis. We could identify all the peptides which were expected from the pro-major basic protein cDNA sequence. Sequence analysis and deglycosylation study revealed that Ser-8, Thr-9, Ser-46 and Asn-70 were glycosylated. The results indicated that proMBP has three types of sugar chains, O-glycoside, N-glycoside and glycosaminoglycan, in the pro-portion.

New approaches to the prediction of preterm delivery

Current approaches to the detection of patients at risk for preterm delivery (PTD) have focused on the diagnosis of preterm labor. However, these approaches are complicated by treatment biases and our inability to convincingly differentiate preterm labor from Braxton-Hicks contractions. Moreover, preterm labor with intact membranes accounts for only one-half of all spontaneous PTDs since uterine contractions follow preterm premature rupture of the membranes (PROM) in an additional 50% of cases. Clinical dogma holds that the prevention of PTD requires the early detection of at risk patients. However, clinical indicators of PTD risk including cervical change, uterine contractions, vaginal bleeding, maternal demographic featuers and obstetrical history have poor sensitivity and/or specificity. Fortunately, an improved understanding of the association between preterm parturition and cervical, chorionic and decidual extracellular matrix degradation has led to a number of promising new biochemical indices of the proteolytic processes leading to PTD. These include measurement of serum collagenase activity and assessment of cervico-vaginal granulocyte elastase and oncofetal fibronectin levels. It remains to be seen, however, whether an improved detection of patients at risk will lead to a reduction in the occurrence of PTD.

Effects of interleukin-6 on the metabolism of connective tissue components in rheumatoid synovial fibroblasts

OBJECTIVE

High levels of interleukin-6 (IL-6) have been found in the synovial fluid of patients with rheumatoid arthritis (RA). We undertook the present study to investigate the role of IL-6 in this disease.

METHODS

We examined the effects of IL-6, in comparison with IL-1, on the biosynthesis of extracellular matrix macromolecules and of matrix-degrading proteinases in rheumatoid synovial fibroblasts.

RESULTS

In rheumatoid synovial fibroblasts, IL-6 by itself enhanced the production of plasminogen activator, its inhibitor, and tissue inhibitor of metalloproteinases, whereas it did not modulate the biosynthesis of precursor of matrix metalloproteinase 1 (proMMP-1) (tissue collagenase), proMMP-3 (stromelysin), or connective tissue components. However, IL-1-induced production of proMMP-1 and proMMP-3 was preferentially augmented by IL-6.

CONCLUSION

These results suggest that in RA, IL-6 may participate along with IL-1 in fine tuning of the catabolism of connective tissue components, by modulating the balance between connective tissue-degrading enzymes and their inhibitors.

Effects of interleukin-1 (IL-1) on postsurgical macrophage secretion of protease and protease inhibitor activities

Although peritoneal macrophages secrete a variety of inflammatory mediators and proteases during postsurgical repair of the peritoneum, regulation of this secretion is poorly understood. Here, the responsivity of peritoneal macrophages to interleukin-1 (IL-1) stimulation in vitro, measured by the secretion of protease and protease inhibitor activities, was evaluated as a function of postsurgical time. Macrophages were harvested at various times after peritoneal sidewall abrasion, isolated by discontinuous density centrifugation and cultured with varying concentrations of IL-1. IL-1 increased the secretion of plasminogen activator (PA) activity by peritoneal macrophages in a concentration-dependent manner on postsurgical Days 0, 3, 10, and 14. Macrophages harvested on postsurgical Day 1 after surgery responded only to high concentration of IL-1, while on Days 5 and 7 all doses of IL-1 stimulate PA. On Days 7, 10, and 14 after surgery, the secretion of PA activity (after acid treatment) by postsurgical macrophages was generally high and increased with IL-1 treatment. The level of PA activity after inactivation of acid labile inhibitors (PAI) also increased in a dose-dependent manner on Days 0, 3, and 5. Although Day 1 macrophages expressed the highest PAI activity of all groups, they had relatively low responsivity to IL-1 with regards to PAI secretion. The level of elastase activity by postsurgical macrophages was lowest on Day 1, highest on Day 7, and decreased thereafter. All concentrations of IL-1 inhibited elastase activity of macrophages on Day 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and properties of bovine nasal hyaline cartilage collagenase

1. Collagenase from bovine nasal hyaline cartilage was extracted with 1 and 3 M NaCl in Tris-CaCl2 buffer. 2. Two peaks of collagenase activity were revealed on DE52 ion exchange column, collagenase 1 and collagenase 2. 3. The apparent mol. wt of collagenase 1 and 2 as determined by SDS-PAGE were 68 and 43 kDa, respectively. 4. Both enzymes degrade native collagen type II into two characteristic products, TCA(3/4) and TCB(1/4), at 25 degrees C and pH 7.6. 5. Trypsin and aminophenylmercuric acetate were capable of increasing the collagenase 1 activity. 6. The two enzymes can be characterized as metalloproteinases since they were inhibited by EGTA and 1,10-phenanthroline. The use of proteinase inhibitors (N-ethylmaleimide, iodoacetic acid, phenylmethylsulphonyl fluoride, soybean trypsin inhibitor, pepstatin, dithiothreitol) showed that the enzymes do not contain serine, cysteine or aspartic acid in their active sites.