Preliminary Evaluation of the Safety and Probiotic Potential of Akkermansia muciniphila DSM 22959 in Comparison with Lactobacillus rhamnosus GG

In this study, for the first time, we examined some of the physico-chemical properties of the cell surface of Akkermansiamuciniphila DSM 22959, comparing it with those of Lactobacillusrhamnosus GG-one of the most extensively studied probiotic microorganisms. In particular, hydrophobicity, auto-aggregation, co-aggregation, and biofilm formation were investigated. In addition, antibiotic susceptibility, co-culture, and antimicrobial activity of the two strains were compared. Hydrophobicity was evaluated using xylene and toluene, showing that A. muciniphila DSM 22959 possessed moderate hydrophobicity. A. muciniphila showed a faster and higher auto-aggregation ability than Lb. rhamnosus GG, but a lower aptitude in biofilm formation. In the co-aggregation test, the best performance was obtained by Lb. rhamnosus GG. Regarding the susceptibility to antibiotics, the differences between the two strains were remarkable, with A. muciniphila DSM 22959 showing resistance to half of the antibiotic tested. Interesting results were also obtained with regard to the stimulating effect of Lb. rhamnosus GG on the growth of A. muciniphila when co-cultured.

Interleukin-10 inhibition of gelatinases in fetal membranes: therapeutic implications in preterm premature rupture of membranes

OBJECTIVE

To examine the effect of interleukin-10 on production and regulation of gelatinases by amniochorion in an in vitro model of infection.

METHODS

We placed amniochorionic membranes collected from eight women who had elective repeat cesareans at term in an organ explant culture system. After 48 hours in culture, the membranes were stimulated with lipopolysaccharide (50 ng/mL), and some were costimulated with interleukin-10 (500 ng/mL). Tissue and media samples were collected after 24-hour stimulation. Quantitative polymerase chain reactions and enzyme-linked immunosorbent assays were used to evaluate matrix metalloproteinase 2 and matrix metalloproteinase 9 messenger RNA and proteins, respectively.

RESULTS

Lipopolysaccharide stimulation induced 55.14 transcripts of matrix metalloproteinase 9, compared with 0.83 in control tissues (P <.001). Costimulation with interleukin-10 and lipopolysaccharide significantly reduced matrix metalloproteinase 9 messenger RNA levels to 10 transcripts (P <.001). Lipopolysaccharide stimulation produced 29.25 ng/mL of immunoreactive matrix metalloproteinase 9, which was reduced to 6.3 ng/mL (P(adj) =.016) after costimulation with interleukin-10. Although not significant, matrix metalloproteinase 2 messenger RNA levels were higher in lipopolysaccharide-stimulated tissues (4.37 x 10(6) transcripts) compared with control (2.8 x 10(5) transcripts; P(adj) =.08), with a significant decrease in matrix metalloproteinase 2 messenger RNA levels in interleukin-10- costimulated tissues (2.9 x 10(6); P(adj) =.007). Interleukin-10 costimulation resulted in a significant decrease in matrix metalloproteinase 2 protein production (203.1 [lipopolysaccharide] and 149.75 [with interleukin-10]; P(adj) <.001).

CONCLUSION

Interleukin-10 eliminated lipopolysaccharide induction of matrix metalloproteinase 2 and 9 in amniochorion.

Support for an infection-induced apoptotic pathway in human fetal membranes

OBJECTIVE

Lipopolysaccharide and tumor necrosis factor alpha levels are both elevated in the amniotic fluid of women during infection-associated preterm labor and premature rupture of fetal membranes. Our laboratory has shown that apoptosis is associated with premature rupture of fetal membranes but is not associated with preterm labor. The exact pathway that leads to apoptosis-mediated premature rupture of fetal membranes is still unclear. Because infection and increased inflammatory cytokine response are associated with the majority of cases of premature rupture of fetal membranes, we examined the roles of bacterial lipopolysaccharide and tumor necrosis factor alpha in inducing the proapoptotic caspase pathway in fetal membranes.

STUDY DESIGN

Amniochorionic membranes collected from women undergoing elective repeat cesarean delivery at term were placed in an organ explant system. At the end of a 48-hour incubation period, membranes were stimulated with lipopolysaccharide (50 ng/mL) and recombinant tumor necrosis factor (50 ng/mL). Total ribonucleic acid extracted from these samples was subjected to reverse transcription and two separate sets of multiple polymerase chain reaction. One set studied the expression of Fas, Fas ligand, caspase 8, Fas-associated death domain, and tumor necrosis factor receptor-associated death domain genes and the second set studied the expression of caspase 2, 4, 6, 7, and 10. Caspase 2, 3, and 9 expression was also studied by reverse transcriptase-polymerase chain reaction.

RESULTS

Multiple polymerase chain reactions and reverse transcriptase-polymerase chain reactions documented the induction of Fas and caspase 2, 3, 7, 8, and 9 genes in amniochorion after lipopolysaccharide and tumor necrosis factor stimulation compared with the nonstimulated controls. Neither lipopolysaccharide nor tumor necrosis factor induced Fas ligand expression in human fetal membranes. Caspase 3, 4, and 6, Fas-associated death domain, and tumor necrosis factor receptor-associated death domain expressions were constitutive in all the tissues tested; however, tumor necrosis factor receptor-associated death domain expression appeared stronger in tumor necrosis factor-stimulated tissues.

CONCLUSION

The presence of the signal docking proteins tumor necrosis factor receptor-associated death domain and Fas-associated death domain and the induction of caspase cascade initiators (caspase 2, 8, and 10) and effector caspases (caspase 3, 6, 7, and 9) by lipopolysaccharide and tumor necrosis factor suggest that tumor necrosis factor-tumor necrosis factor receptor-mediated apoptosis may occur in the human fetal membrane.

Programmed cell death (apoptosis) as a possible pathway to metalloproteinase activation and fetal membrane degradation in premature rupture of membranes

OBJECTIVE

Increased matrix metalloproteinase 2 expression and activity are associated with premature rupture of fetal membranes. A proapoptotic protein produced in response to deoxyribonucleic acid fragmentation, p53, can bind to the matrix metalloproteinase 2 gene promoter and cause increased gene expression. It promotes apoptosis by inducing the expression of the proapoptotic bax gene and inhibiting the antiapoptotic bcl-2 gene. This study was undertaken to investigate the expression pattern of apoptotic elements in pregnancy complications that may cause increased expression of the gene for matrix metalloproteinase 2.

STUDY DESIGN

Amniochorial membranes were collected from the following groups of women: (1) women with premature rupture of fetal membranes, (2) women with preterm labor and intact membranes, and (3) women with term labor after vaginal delivery. Deoxyribonucleic acid fragmentation was tested with ligation-mediated polymerase chain reaction and the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyribonucleoside triphosphate end-labeling assay. Matrix metalloproteinase 2, p53, bcl-2, and bax gene expression patterns were studied with quantitative competitive polymerase chain reaction. Statistical analysis was performed with the Tukey-Kramer multiple comparison test.

RESULTS

Quantitative competitive polymerase chain reaction documented a 10-fold increase in the expression of the gene for matrix metalloproteinase 2 in premature rupture of fetal membranes with respect to term and preterm labor. This induction coincided with an increase in the expressions of the proapoptotic genes p53 and bax and a drop in the expression of the antiapoptotic gene bcl-2. Ligation-mediated polymerase chain reaction revealed deoxyribonucleic acid fragmentation in specimens from premature rupture of fetal membranes and not in those from preterm labor or labor at term. Histochemical analysis documented fragmented deoxyribonucleic acid in chorionic and amniotic cells.

CONCLUSION

This study suggests that apoptosis is associated with premature rupture of fetal membranes. Deoxyribonucleic acid fragmentation, associated with elevations in the levels of the two proapoptotic gene products evaluated (p53 and bax ) and a drop in the level of the antiapoptotic bcl-2, was seen in premature rupture of the fetal membranes. Induction of matrix metalloproteinase 2 may be a function of p53 gene expression increase in premature rupture of fetal membranes.

Amniochorion gelatinase-gelatinase inhibitor imbalance in vitro: a possible infectious pathway to rupture

OBJECTIVE

To estimate the effect of lipopolysaccharide on gelatinases and tissue inhibitors of matrix metalloproteinase 2 (gelatinase inhibitor) balance in human fetal membranes.

METHODS

Amniochorionic membranes in organ explant were stimulated with 1000 ng/mL lipopolysaccharide for 24 hours after a 48-hour preincubation period. Quantitative competitive polymerase chain reaction (PCR) was done to quantitate messenger RNAs for gelatinase A and B (matrix metalloproteinase 2 and 9) and tissue inhibitor of metalloproteinase 2. Protein levels were assayed by enzyme-linked immunosorbant assay. The molar ratio between gelatinases and tissue inhibitor of metalloproteinase 2 was calculated. Statistical evaluation was done by Mann-Whitney U test.

RESULTS

Lipopolysaccharide stimulation produced 3.6 x 10(6) and 366 transcripts of gelatinase A and B, respectively, compared with only 5.9 x 10(4) (P = .009) and three transcripts (P = .006), respectively, in the controls. Lipopolysaccharide stimulation released 210 ng/mL compared with 7 ng/mL of gelatinase A and B proteins compared with 120 (P = .01) and 4.6 ng/mL (P = .3) in controls, respectively. Control amniochorion produced 5.7 x 10(5) transcripts of tissue inhibitor of metalloproteinase 2, whereas lipopolysaccharide stimulation produced 4.1 x 10(5) transcripts (P = .69). Lipopolysaccharide reduced the release of this inhibitor from 114 ng/mL to 68 ng/mL (P = .007). The molar ratio between gelatinases and tissue inhibitor of metalloproteinase 2 increased from a balanced ratio of 1:1 to 3.1:1 after 1000 ng/mL of lipopolysaccharide.

CONCLUSION

Lipopolysaccharide increased the expression and release of gelatinases and decreased its inhibitor, which shifted the balance in favor of gelatinase activity leading to membrane degradation that predisposes to premature rupture of membranes.

MMP/TIMP imbalance in amniotic fluid during PROM: an indirect support for endogenous pathway to membrane rupture

OBJECTIVE

We theorize that excessive degradation of the fetal membrane extracellular matrix (ECM) by specific matrix metalloproteinases (MMPs) results in preterm premature rupture of the membranes (PROM). Active, inhibitor free MMP2 and 9 (gelatinase A and B respectively) can degrade the amniochorion basement membrane Type IV collagen to initiate rupture. This study examines the levels of the gelatinases and their natural inhibitors (tissue inhibitor of matrix metalloproteinases-TIMPs) in the amniotic fluid during PROM, preterm labor (PTL) and at term.

METHODS

A total of 51 AF samples were collected from the following groups of patients. Group 1: Women with PTL and no ROM (n = 16) Group 2: Women with PROM (n = 16) irrespective of labor status Group 3: Women at term with intact membranes undergoing cesarean delivery irrespective of labor status (n = 19). ELISA was used to assay MMP2, MMP9, TIMP1 and TIMP2 levels in the amniotic fluid. The active, TIMP free levels of MMP2 were quantitated by zymography followed by computerized densitometry. Active MMP9 was measured using a bioassay that specifically detects MMP9 activity. Statistical analysis was performed by Tukey-Kramer multiple comparison method.

RESULTS

PROM is associated with increased MMP2 levels (mean 2125 ng/ml;) when compared with term (mean 1455 ng/ml; p < 0.01) or PTL where a non significant increase was seen (mean 1862 ng/ml; p = ns). MMP9 levels were higher in PROM (mean 15.03 ng/ml) than at term (mean 1.14 ng/ml; p < 0.001) or PTL (mean 3.75 ng/ml; p < 0.01). TIMP1 levels were slightly increased during PROM (mean 3143 ng/ml) compared to term (mean 1892 ng/ml; p < 0.05) pr PTL where a non significant change was seen (mean 2406 ng/ml; p = ns). TIMP2 levels were decreased in PROM (mean 98 ng/ml) compared with term (mean 176 ng/ml; p < 0.05) and PTL (mean 236 ng/ml; p < 0.001). Active, TIMP free MMP2 levels were increased during PROM (mean 233 pg/ml) compared to those at term (mean 132 pg/ml; p < 0.05) or PTL (mean 132 pg/ml; p < 0.05). Active forms of MMP9 were seen only during PROM (mean 632 pg/ml).

CONCLUSION

Active, TIMP free forms of MMP2 and 9 are increased in the amniotic fluid of women with PROM. These MMPs can degrade the amniochorion basement membranes and other ECM components resulting in PROM.

Stromelysins in placental membranes and amniotic fluid with premature rupture of membranes

OBJECTIVE

To determine the expression and site of production of stromelysins in fetal membranes and to measure stromelysin 1 levels in amniotic fluid and amniochorion culture media.

METHODS

Amniochorionic membranes were cultured from organ explant. Membranes were stimulated with lipopolysaccharide for 24 hours after a 48-hour preincubation period. Membranes were also collected from women after vaginal deliveries. RNA samples from those tissues were subjected to reverse transcriptase-polymerase chain reaction using primers specific for stromelysin 1, stromelysin 2, stromelysin 3, and matrilysin. In situ hybridization and immunohistochemistry were used to localize stromelysin mRNA and peptide. Levels of stromelysin 1 in culture media and amniotic fluid collected from women with preterm premature rupture of membranes (PROM) and at term with intact membranes were compared using enzyme-linked immunosorbant assay.

RESULTS

Amniochorion in culture and from laboring and nonlaboring women expressed all three stromelysins. In situ hybridization showed stromelysin mRNA in amnion, chorion, and extracellular matrix. Immunohistochemical analysis localized stromelysin 1 protein to those same regions. Amniotic fluid levels of stromelysin 1 were higher in preterm PROM amniotic fluids (median 3.2 ng/mL) compared with term deliveries with intact membranes (median 1.3 ng/mL) (P = .02). Lipopolysaccharide stimulation in culture increased the release of stromelysin 1 from fetal membranes compared with control (median 70.35 versus 15.8 ng/mL, respectively, P = .05).

CONCLUSION

Human fetal membranes are a source of stromelysins 1, 2, and 3. Increased stromelysin 1 during preterm PROM and in vitro after lipopolysaccharide stimulation suggests a possible effect of that matrix metalloproteinase in PROM.

Immunoreactivity of human fetal membranes to peptidoglycan polysaccharide (PGPS): cytokine response

OBJECTIVE

Group-B Streptococcus has been associated with preterm labor and other pregnancy related complications. This study was performed to evaluate the effect of peptidoglycan polysaccharide (PGPS) derived from a beta hemolytic Streptococcal cell wall on amniochorion cytokine production and to compare PGPS effects with lipopolysaccharide (LPS), which is the Gram negative counterpart of PGPS.

STUDY DESIGN

Amniochorionic membranes collected from women not in labor, and undergoing elective repeat C-section were placed in an organ explant system. Membranes were stimulated separately with 50 ng/ml of small (100p), large (10s) fractions of PGPS or LPS respectively immediately after collection and after a stabilization period of 48 hrs. Media samples were collected at 3, 6, 9, 12 and 24 hrs for protein analysis after each stimulation. Media samples were analyzed by ELISA for IL-6 and IL-8.

RESULTS

Both forms of PGPS and LPS stimulated IL-6 and IL-8 production by human fetal membranes. Of note is that LPS stimulated IL-6 to a greater degree than IL-8, while PGPS stimulated IL-8 to a greater degree than IL-6. No statistical difference was seen in the levels of either one of these cytokines for the larger or smaller fragments of PGPS. Time course studies documented a 3-hour lag phase when tissues are stimulated directly after collection which was absent when tissues are stimulated after a 48-hour stabilization period.

CONCLUSION

Both PGPS and LPS stimulate cytokine production differently from fetal membranes. This supports the theory that different bacteria may affect the host in contrasting ways which may lead to a distinct host response, i.e. PROM vs. PTL.

Presence of four tissue inhibitors of matrix metalloproteinases (TIMP-1, -2, -3 and -4) in human fetal membranes

PROBLEM

Matrix metalloproteinases play a critical role in fetal membrane extracellular matrix (ECM) homeostasis. Remodeling of the ECM during normal placental development is a balanced activity between various matrix metalloproteinases and their tissue-specific counter-regulatory proteins (tissue inhibitors of matrix metalloproteinases [TIMPs]). We have reported the presence of TIMP-1 and TIMP-2 in placental membranes in culture. In this study we have investigated the membrane expression of TIMP-1 and TIMP-2 during labor and nonlabor conditions and also the presence of two novel TIMP family members (TIMP-3 and TIMP-4).

METHOD OF STUDY

Amniochorionic membranes collected from women undergoing Cesarean section and were cultured in an organ explant system. Membranes were also collected from laboring women after vaginal delivery. Samples were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) using primers specific for TIMP-1, TIMP-2, TIMP-3, and TIMP-4. Localization of TIMP mRNAs was accomplished by in situ hybridization, and peptides were localized by immunocytochemistry.

RESULTS

RT-PCR data demonstrated the expression of all the TIMPs in tissues from laboring and nonlaboring women as well as in cultured membranes. TIMP-4 expression was seen in RT-PCR, however, only a faint band was visible in all the tissues tested. In situ hybridization localized the TIMP mRNAs to the amnion, chorion, and to scattered cells in the connective tissue.

CONCLUSION

Human fetal membrane cells (amniochorion and decidua) express mRNA for all the TIMPs studied so far.

Structure-activity relationships of the Kvbeta1 inactivation domain and its putative receptor probed using peptide analogs of voltage-gated potassium channel alpha- and beta-subunits

Certain beta-subunits exert profound effects on the kinetics of voltage-gated (Kv) potassium channel inactivation through an interaction between the amino-terminal "inactivation domain" of the beta-subunit and a "receptor" located at or near the cytoplasmic mouth of the channel pore. Here we used a bacterial random peptide library to examine the structural requirements for this interaction. To identify peptides that bind Kv1.1 we screened the library against a synthetic peptide corresponding to the predicted S4-S5 cytoplasmic loop of the Kv1.1 alpha-subunit (residues 313-328). Among the highest affinity interactors were peptides with significant homology to the amino terminus of Kvbeta1. We performed a second screen using a peptide from the amino terminus of Kvbeta1 (residues 2-31) as "bait" and identified peptide sequences with significant homology to the S4-S5 loop of Kv1.1. A series of synthetic peptides containing mutations of the wild-type Kvbeta1 and Kv1.1 sequences were examined for their ability to inhibit Kvbeta1/Kv1.1 binding. Amino acids Arg20 and Leu21 in Kvbeta1 and residues Arg324 and Leu328 in Kv1.1 were found to be important for the interaction. Taken together, these data provide support for the contention that the S4-S5 loop of the Kv1.1 alpha subunit is the likely acceptor for the Kvbeta1 inactivation domain and provide information about residues that may underlie the protein-protein interactions responsible for beta-subunit mediated Kv channel inactivation.

The effect of transforming growth factor and interleukin-10 on interleukin-8 release by human amniochorion may regulate histologic chorioamnionitis

OBJECTIVE

Amniochorion is a source of interleukin-8 during infection and inflammation. In this study we investigate the role of 2 immunoinhibitory cytokines, transforming growth factor and interleukin-10, in regulating interleukin-8 production from human fetal membranes and define their mechanism of regulation.

STUDY DESIGN

Amniochorion was placed in an organ explant system for 72 hours. Tissues were stimulated with lipopolysaccharide (50 ng/mL), lipopolysaccharide plus transforming growth factor-beta (50/50, 50/100), transforming growth factor-beta (50 and 100 ng/mL), lipopolysaccharide plus interleukin-10 (50/50 and 50/100), and interleukin-10 (50 and 100 ng/mL) in culture. Tissue and media samples were frozen until quantitation of interleukin-8 messenger ribonucleic acid and protein. Quantitation of messenger ribonucleic acid was performed by quantitative competitive polymerase chain reaction and protein by enzyme-linked immunoassay, respectively.

RESULTS

Lipopolysaccharide-stimulated tissues produced approximately 6 x 10(6) molecules per microliter of interleukin-8 messenger ribonucleic acid compared with 6 x 10(3) molecules per microliter in controls. Transforming growth factor-beta alone and lipopolysaccharide plus transforming growth factor-beta stimulation produced 6 x 10(5) and 6 x 10(4) molecules of interleukin-8 messenger ribonucleic acid per microliter, respectively. Tissues stimulated with lipopolysaccharide plus 50 ng/mL interleukin-10 produced approximately 600 molecules per microliter of interleukin-8 messenger ribonucleic acid, whereas no amplifiable messenger ribonucleic acid was detected in tissues treated with lipopolysaccharide plus 100 ng/mL interleukin-10. Tissues treated with interleukin-10 alone produced 6 x 10(3) molecules of messenger ribonucleic acid, similar to control levels. Enzyme-linked immunosorbent assay data showed similar levels of interleukin-8 peptide release from lipopolysaccharide and lipopolysaccharide plus transforming growth factor-beta-treated fetal membranes. A dose-dependent decrease in interleukin-8 peptide release was seen in tissues treated with lipopolysaccharide plus interleukin-10, whereas stimulation with transforming growth factor or interleukin-10 alone resulted in interleukin-8 peptide release similar to that of control levels.

CONCLUSION

Transforming growth factor-beta seems to have no effect on interleukin-8 protein production in the presence of an infectious agent; however, a drop in messenger ribonucleic acid levels was observed. Interleukin-10 in the presence of lipopolysaccharide showed down-regulation of interleukin-8 messenger ribonucleic acid expression and peptide production. These data suggest that fetal membrane interleukin-8 production can be controlled by interleukin-10 during an infectious process.

Expression of a progelatinase activator (MT1-MMP) in human fetal membranes

PROBLEM

The finding of MMP-2 (which degrades type IV collagen) and TIMP-2 (the tissue inhibitor of MMP) in fetal membranes suggests the possibility of membrane self-destruction as an etiology of premature rupture of fetal membranes. MMP-2 is activated by a membrane-bound MMP (MT1-MMP). This study was undertaken to detect the presence of MT1-MMP in human fetal membranes.

METHOD OF STUDY

Fetal membranes were placed in an organ explant system and stimulated with lipopolysaccaride (LPS). MT1-MMP expression was studied in frozen tissues by reverse transcriptase (RT)-polymerase chain reaction (PCR) using primers designed in our laboratory. DNA sequence analysis was performed to verify the specificity of PCR products. In situ hybridization and immunocytochemistry were used to localize MT1-MMP mRNA and peptide, respectively.

RESULTS

RT-PCR data indicated the presence of mRNA for MT1-MMP in fetal membranes. Although PCR is not quantitative, no differences in mRNA band intensities were noticed after LPS stimulation. MT1-MMP expression was constitutive throughout the culture period. In situ hybridization demonstrated amnion, chorionic laeve, cytotrophoblast cells, and the cells in the reticular and spongy layer of the extracellular matrix as the origin of MT1-MMP mRNA and peptide.

CONCLUSIONS

This is the first study documenting the amniochorionic membrane as a source of MT1-MMP mRNA and peptide. Activation of progelatinase A requires the presence of this membrane-associated MMP. The finding of MT1-MMP in a tissue already known to produce MMP-2 and TIMP-2 documents the full system for activation and inhibition of this gelatinase. During infection, an imbalance in the expression of MT1-MMP, MMP-2 and TIMP-2 may constitute an endogenous pathway of membrane degradation.

Cloning and tissue distribution of the human G protein beta 5 cDNA

Heterotrimeric G proteins integrate signals between receptors and effector proteins. We have cloned the human beta 5 subunit from a human brain cDNA library. The clone has a 1059 bp open reading frame and is highly homologous to the murine clone. In contrast to the brain specific mouse beta 5, northern analysis showed it to be expressed in multiple tissues.

IL-15, a novel cytokine produced by human fetal membranes, is elevated in preterm labor

PROBLEM

Interleukin (IL)-15 is a novel cytokine known to have functions similar to those of IL-2 in the cell-mediated immune response. The objectives of this study were to determine whether IL-15 levels change in labor or preterm labor and to identify the regulatory agents and the site of production of IL-15.

METHOD OF STUDY

Amniochorionic membranes were cultured in an organ explant system and were stimulated with lipopolysaccharides (LPSs). Samples were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) using specific primers for IL-15 and IL-2. The localization of mRNA and protein was accomplished by in situ hybridization and immunocytochemistry. IL-15 was measured in culture media and amniotic fluid from term and preterm gestations by enzyme-linked immunoadsorbent assay (ELISA).

RESULTS

RT-PCR indicated the expression of IL-15 mRNA in the amniochorion. In situ hybridization and immunocytochemistry documented that mRNA and peptide for IL-15 are found in amnion, chorion, and decidual cells. ELISA results indicated no significant increase of IL-15 peptides in the culture media after LPS stimulation. Maximum levels of this cytokine were seen in the amniotic fluid (AF) of women with preterm labor compared to term labor. AF levels were not higher in preterm-labor patients with proved infection compared with those without infection. RT-PCR-based detection also showed the presence of two isoforms of IL-15 mRNA known to code for two different leader peptide sequences. IL-2 mRNA expression was not observed in the fetal membranes.

CONCLUSIONS

The presence of IL-15 mRNA and peptide in the amniochorion and decidua and its increased presence in the AF during preterm labor suggests a possible role for IL-15 in preterm labor. Amniochorion is also shown to possess two IL-15 isoform leader sequences, the differential expression of which may be involved in the regulation of IL-15 secretion.

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.

Interleukin-10 and transforming growth factor-beta inhibit amniochorion tumor necrosis factor-alpha production by contrasting mechanisms of action: therapeutic implications in prematurity

OBJECTIVE

This study was designed to detect the regulatory effect of the immunoinhibitory cytokines interleukin-10 and transforming growth factor-beta on the amniochorion production of tumor necrosis factor-alpha.

STUDY DESIGN

Amniochorionic membranes were collected from women undergoing elective repeat cesarean section with no history of infection. Membranes were placed in organ explant culture for 48 hours and then stimulated with lipopolysaccharide (50 ng/ml), lipopolysaccharide plus interleukin-10 (50/ 50, 50/100 ng/ml), interleukin-10 (50 and 100 ng/ml), lipopolysaccharide plus transforming growth factor-beta (50/50 and 50/100 ng/ml), and transforming growth factor-beta (50 and 100 ng/ml). At the end of a 24-hour stimulation tissue samples were frozen for ribonucleic acid analysis and media samples were frozen for enzyme-linked immunosorbent assay. Quantitation of the messenger ribonucleic acid was accomplished by quantitative competitive polymerase chain reaction, and tumor necrosis factor-alpha protein was assayed by use of enzyme-linked immunosorbent assay.

RESULTS

Lipopolysaccharide stimulation of fetal membranes produced approximately 60,000 molecules of tumor necrosis factor-alpha messenger ribonucleic acid, whereas control tissue produced none. Lipopolysaccharide plus interleukin-10 stimulation resulted in a dose-dependent decrease in tumor necrosis factor-alpha messenger ribonucleic production (transcriptional regulation) to 6000 (50/50) and 600 (50/100) molecules. Enzyme-linked immunosorbent assay performed on media samples from these experiments demonstrated a dose-dependent reduction in tumor necrosis factor-alpha peptide release. Stimulation of membranes with lipopolysaccharide plus transforming growth factor-beta had minimal effects on tumor necrosis factor-alpha messenger ribonucleic acid and protein production compared with lipopolysaccharide-treated samples. Membranes stimulated with interleukin-10 alone showed no effect on messenger ribonucleic acid or protein levels and remained similar to the levels seen in control tissues. In the absence of lipopolysaccharide, transforming growth factor-beta treatment produced a dramatic decrease in tumor necrosis factor-alpha peptide levels without affecting messenger ribonucleic acid levels.

CONCLUSION

In the presence of a stimulatory agent, interleukin-10 down-regulates tumor necrosis factor-alpha release from cultured human amniochorionic membranes. Transforming growth factor-beta seems to have some stimulatory effect on transcription, and no effect on translation was seen with concurrent lipopolysaccharide stimulation. However, down-regulation of tumor necrosis factor-alpha peptide by transforming growth factor was seen in fetal membranes when not overridden by an inflammatory stimulant. This study suggests that interleukin-10 and transforming growth factor-beta can regulate tumor necrosis factor-alpha release from amniochorion under different conditions and by a different mechanism.

Interleukin-10 inhibition of interleukin-6 in human amniochorionic membrane: transcriptional regulation

OBJECTIVE

Our purpose was to study the regulatory effects of recombinant interleukin-10 on interleukin-6 messenger ribonucleic acid and protein production by human fetal membranes.

STUDY DESIGN

Amniochorionic membranes were collected from women undergoing elective cesarean section. Membranes were maintained in an organ explant system and stimulated with media containing lipopolysaccharide (50 ng/ml) and various amounts of recombinant interleukin-10 (10, 50, 100 ng/ml). Experiments were conducted in a dose- and time-dependent manner. Transcription and translation of interleukin-6 were monitored with quantitative reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Interleukin-10 stimulation of amniochorionic membranes in culture produced a dose-dependent decrease in the production of interleukin-6 messenger ribonucleic acid and protein. Quantitative polymerase chain reaction was used to document a decrease in interleukin-6 messenger ribonucleic acid, which paralleled the decrease in peptide levels as detected with enzyme-linked immunosorbent assay. The interleukin-10 effect was present only when tissue was concurrently stimulated with lipopolysaccharide. Interleukin-10 inhibition could not be produced in the absence of lipopolysaccharide stimulation.

CONCLUSION

Addition of interleukin-10 to culture media leads to transcriptional regulation of interleukin-6, which results in decreased production of both messenger ribonucleic acid and protein by human amniochorionic membranes. The decrease in interleukin-6 is a dose-dependent effect of interleukin-10. This finding may have important implications with respect to a possible role for interleukin-10 or an interleukin-10 stimulatory factor in the management of preterm labor associated with the presence of inflammatory cytokines.

Ferning of amniotic fluid contaminated with blood

The diagnosis of rupture of the membranes by traditional methods of nitrazine paper determination and fern crystallization has been reported to be 93-98% accurate. Although the presence of contaminants in amniotic fluid has been reported to reduce this accuracy, the literature is conflicting concerning these effects. We examined the effect of blood contamination on the accuracy of diagnosing ruptured membranes. Amniotic fluid was obtained from 38 patients between 16-38 weeks' gestational age who underwent amniocentesis. Amniotic fluid was immediately mixed with freshly obtained, heparinized fetal cord blood in varying concentrations (blood to amniotic fluid 1:5, 1:10, 1:20). The slides were examined microscopically for the presence of ferning. All samples were fern-positive, but many had atypical ferns described as "skeletonized." As the concentration of blood to amniotic fluid increased, the number of atypical ferns increased (32 of 38 at 1:5, 22 of 38 at 1:10, and nine of 38 at 1:20). We conclude that the presence of blood may alter the morphology of the fern, but does not act as a contaminant that would affect the accuracy of the test.

Umbilical artery velocimetry as a predictor of adverse outcome in pregnancies complicated by oligohydramnios

Oligohydramnios is associated with increased perinatal mortality and morbidity. Traditional methods of in utero fetal evaluation have been unsuccessful in reliably distinguishing oligohydramnios with normal outcome from that associated with increased perinatal morbidity. A prospective study was undertaken to establish the predictive value of Doppler velocimetry in identifying the fetus with oligohydramnios at increased risk of adverse perinatal outcome. Twenty-two gravid women with subjective oligohydramnios on ultrasound had continuous-wave umbilical artery velocimetry. Subjects were divided into two groups based on the results of Doppler analysis. Group 1 (N = 13) had normal umbilical Doppler waveforms. In this group, 12 of 13 patients had normal perinatal outcome, defined by the absence of intrapartum fetal distress or evidence of intrauterine growth retardation. Group 2 consisted of nine subjects with abnormal waveforms. Perinatal morbidity occurred in 100% in this group. We conclude that an abnormal umbilical artery waveform may provide confirmatory evidence of impending fetal compromise when the antenatal sonographic diagnosis of oligohydramnios is made.

Heat and UV light resistance of vegetative cells and spores of Bacillus subtilis Rec-mutants

The heat and UV light resistance of spores and vegetative cells of Bacillus subtilis BD170 (rec+) were greater than those of B. subtilis BD224 (recE4). Strain BD170 can repair DNA whereas BD224 is repair deficient due to the presence of the recE4 allele. Spores of a GSY Rec+ strain were more heat resistant than spores of GSY Rec- and Uvr- mutants. The overall level of heat and UV light resistance attained by spores may in part be determined by their ability to repair deoxyribonucleic acid after exposure to these two physical mutagens.