Integrins are not involved in the process of human sperm-oolemmal fusion

BACKGROUND: We investigated whether integrins are required forthe human sperm–oocyte binding and fusion processes. METHODS:The expression of several integrin subunits at the human oocyteplasma membrane was investigated using immunofluorescence microscopy,and the functional role of integrins expressed at the humanoocyte surface in sperm–oocyte interaction was studiedusing a zona-free human oocyte binding and fusion assay. A totalof 144 unfertilized oocytes were stained with anti-integrinantibodies and 147 zona-free unfertilized oocytes were inseminatedin the presence of various anti-integrin antibodies that wereexpressed in oocyte plasma membrane. RESULTS: The antibodiesof six integrin subunits (₂, ₃, ₅, ₆, _V, _M) and six integrinsubunits (₁, ₂, ₃, ₄, ₅, ₆) were bound to the surface of fixedunfertilized oocytes. In contrast, the presence of ₁ and ₄ subunitscould not be verified. The human sperm–oocyte bindingwas only partially inhibited by blocking antibodies of ₂, ₃,₅, ₆, _V, _M, ₁, ₂ and ₃ with a maximum of 55% inhibition, butantibodies of ₄, ₅ and ₆ showed no effect on sperm–oolemmalbinding. A similar reduction of the number of fused sperm wasobserved. However, the ratio of fused sperm to total sperm (boundand fused) was not impaired by all integrin antibodies, suggestingthat integrins had no role in the sperm–oolemmal fusionprocess. CONCLUSIONS: These results suggest that one of thebinding mechanisms can be inhibited by integrin antibodies butthat this mechanism does not play an essential role in the humansperm–oolemmal binding and fusion processes. The othermechanisms, insensitive to integrins, may involve both bindingand fusion processes in human oocytes.     

Ovary: Immunolocalization of transforming growth factor-{beta}1 and transforming growth factor-{beta}2 in the mouse ovary during gonadotrophin-induced follicular maturation

An immunohistochemical approach was utilized to evaluate thecellular distribution of transforming growth factor-₁ (TGF₁)and transforming growth factor ₂ (TGF₂) at different stagesof follicle development in the prepubertal mouse ovary underthe following conditions: (i) after pregnant mare's serum gonadotrophin(PMSG) treatment; (ii) after PMSG and human chorionic gonadotrophin(HCG) treatment; (iii) after PMSG and HCG treatment plus mating.In the immature ovary, TGFF₁ and TGF₂ immunoreactivities arelocalized in theca and granulosa cells and in oocytes. AfterPMSG treatment, TGF₁ and TGF₂ immunoreactivities are localizedin granulosa cells; in addition, TGF₂ staining is noted in thematrix surrounding antral cells. Staining for both TGF₁ andTGF₂ drops in the theca but persists in the oocyte. PMSG plusHCG treatment results in a significant increase in TGF₁ andTGF₂ immunoreactivity in the theca and in the maintenance ofTGF₁ staining in both basal granulosa cells and cumulus cellswhereas TGF₂ immunoreactivity is essentially localized in thematrix surrounding cumulus cells. Staining for TGF₁ and TGF₂persists in the oocyte. Following PMSG plus HCG treatment andmating, TGF₁ immunoreactivity is localized in the luteal cellsof corpora lutea and TGF₂ shows a similar localization pattern.This study provides evidence that TGF₁ and TGF₂ peptides areexpressed in specific cell types during induced follicular maturationin the mouse ovary.     

Endocrinology: Substrate dependency of C19 conjugates in hirsute hyperandrogenic women and the influence of adrenal androgen

Serum C₁₉ conjugates, specifically 3-androstanediol glucuronide(3G), reflect peripheral androgen action through the actionof 5-reductase activity. The origin of 5-reduced C₁₉ conjugateshas been controversial and it has been suggested that they arederived primarily from adrenal androgens. We examined concentrationsof 3G, 3-androstanediol sulphate (3S), androsterone glucuronide(AoG) and androsterone sulphate (AoS) in 40 hirsute hyperandrogenicwomen. These patients were divided into four groups based uponindividual, combined or normal concentrations of the adrenalandrogens dehydroepiandrosterone (DHEAS) and 11-hydroxy-androstenedione.Testosterone, unbound testosterone and androstenedione weresimilar in these groups. Serum 3G was equally high in all groupsand was correlated significantly with hirsutism, while the otherconjugates were not. Androsterone glucuronide was raised inall groups but was higher in patients with raised DHEAS. Serum3S was raised in all groups and was higher where both adrenalandrogens were raised. Serum AoS was highly correlated withDHEAS. Serum 3G was correlated with unbound testosterone andandrostenedione but not with the adrenal androgens. The glucuronideconjugates were correlated with one another as were the sulphateconjugates but glucuronides and sulphates were not correlated.These data confirm ovarian and adrenal dependency of C₁₉ conjugates.Serum 3G appears to reflect hirsutism most accurately and isleast dependent on adrenal androgens in patients with mixedhyperandrogenism.     

Integrins and adhesion mlecules: Cell adhesion molecules on the oocyte and preimplantation human embryo

The presence of cell adhesion molecules on human oocytes, earlyembryos, and pre-hatched blastocysts was examined by indirectimmunofluorescence and compared to the distribution found onfirst trimester villous placenta with the same antibodies. Sixintegrin subunits (3, V, 1, 3, 4, 5) were observed consistentlythroughout preimplantation development. Evidence was also obtainedfor the presence of integrin subunits 2, 4, L, 2, and 7 on asmall number of oocytes. A more restricted developmental analysisof E-cadherin, ICAM-1, NCAM, and VCAM-1 demonstrated that thesecell adhesion molecules are also present on oocytes and earlyembryos. L-selectin was detected on oocytes but was not foundon 8-cell embryos. The oocyte and early blastomeres have complexsurfaces in which the integrin and CAM families are represented.     

Concentration of interleukin-1{beta} correlates with prostaglandin E2 and F2{alpha} in human pre-ovulatory follicular fluid

To investigate the role(s) of interleukin-1 (IL-1) in humanovarian function, we measured the concentrations of IL–1,prostaglandins (PGs) and steroids in follicular fluid of 90stimulated ovaries, with reference to oocyte maturation. Concentrationsof IL-1 were significantly higher in the follicles from whichmature oocytes were recovered than in follicles from which oocytescould not be recovered (P < 0.05). IL-1 concentrations alsoincreased in association with oocyte maturation. Positive significantcorrelations were seen between IL-1 and prostaglandin E2 (PGE2)(r = 0.47, P < 0.001), and between IL-1 and prostaglandinF₂ (PGF₂) (r = 0.22, P < 0.05) in pre-ovulatory follicularfluid, but not between IL–1 and oestradiol, or betweenIL-1 and oestradiol, or between IL-1 and progesterone. 0Follicularfluid IL-1 might contribute to prostaglandin-induced oocytematuration and ovulation.     

Immunology: {beta}2-Glycoprotein I-dependent and -independent anticardiolipin antibodies in healthy pregnant women

The purpose of this study was to determine the association between₂-glycoprotein I (₂GPI)-dependent anticardiolipin antibodies(aCL) and ₂GPI-independent aCL and their respective relevanceto adverse pregnancy outcomes. Therefore, we prospectively studied210 normal pregnant women, utilizing a modified enzyme-linkedimmunosorbent assay method for ₂GPI-dependent and -independentaCL. Seven of the 210 pregnant women (3.3%) demonstrated evidencefor ₂GPI-independent immunoglobulin G (IgG)-aCL. Two patients,who also appeared positive for ₂GPI-dependent IgG-aCL, wereproven to be false positives. Amongst the 210 patients, notone was thus positive for ₂GPI-dependent aCL. Women with ₂GPI-independentaCL demonstrated no adverse pregnancy outcomes. These resultssuggest that the presence of ₂GPI-independent aCL is not associatedwith the presence of 2GPI-dependent aCL, though it may giverise to false positive results. Since the presence of 2GPI-independentaCL does not appear to be associated with adverse pregnancyoutcomes, ₂GPI-dependent assays may represent better markersof miscarriage risk.     

Interleukin-1{alpha} and -{beta} modulation of luteinized human granulosa cell oestrogen and progesterone biosynthesis

This study was designed to test the hypothesis that inter-leukin-1(IL-1) and directly affect progesterone, and oestradiol productionin cultures of purified human granulosa cells. Luteinized granulosacells were obtained from women during in-vitro fertilizationcycles. Granulosa cells with and without associated white bloodcells were cultured in the presence of IL-1 and IL-1 (0.5–50ng/ml) for 48 h. Media were changed at 24 h intervals and assayedfor progesterone and oestradiol. In separate experiments, granulosacell viability was assessed with the tetrazolium salt reductionassay, haemocytometer cell counts, and Trypan blue dye exclusion.Our results indicate that progesterone synthesis by basal andhuman chorionic gonadotrophin (HCG)-stimulated granulosa cellsco-cultured with white blood cells was inhibited by 5.0 ng/mlof IL-1 and IL-1 at 48 h of culture. In the presence of whiteblood cells, granulosa cell oestradiol synthesis was inhibitedby IL-1 but not IL-1. Oestradiol was inhibited after both 24and 48 h of culture and was maximally affected by 5.0 ng/mlof IL-1. In contrast, basal and HCG-stimulated oestradiol productionby granulosa cells cultured free of white blood cells was inhibitedonly by IL-1. IL-1 at 5.0 ng/ml produced maximal inhibitionof basal oestradiol (57%) and HCG-stimulated oestradiol (41%)production at 48 h of culture. Gonadal steroid inhibition byIL-1 and IL-1 was not mediated through cytotoxic or antiproliferativeeffects on granulosa cells. Specificity of the granulosa cellresponse to IL-1 and IL-1 was demonstrated by abrogation ofsteroid inhibition with anti-IL-1 and IL-1 neutralizing antibodies.In conclusion, IL-1 directly inhibited the production of oestradiolby human ovarian granulosa cells. IL-1 and IL-1 also exertedindirect effects on steroid production via white blood cellsthat are usually present in granulosa cell cultures if stepsare not taken to remove them. These data support the hypothesisthat cytokines play an important role in intra-ovarian regulationof steroid biosynthesis.     

Expression of integrins by human trophoblast and differential adhesion to laminin or fibronectin

The process of placental implantation involves a series of transformationsof trophoblast from a single polarized epithelial layer restingon a basement membrane (villous trophoblast), to cellular aggregates(trophoblast columns) which ultimately disperse to invade uterinedecidua as individual cells (interstitial trophoblast). Suchtissue re-modelling is associated with changes in the constituentsof the extracellular matrix and in the expression of matrixreceptors by the cells, the most relevant being the family ofintegrins which bind to laminin and fibronectin. In this studywe show, by immunohistology and flow cytometry, a gradual lossof laminin receptors with the concomitant acquisition of fibronectinreceptors as trophoblast is transformed from the villous phenotype,through the cell columns, into the extravillous population.The pattern of staining for the ₅, ₆, ₁ and ₄ subunits indicatesthat the integrins expressed by trophoblast are predominantlythe ₅₁ and the ₆₄ heterodimers. We have also shown that isolatedtrophoblast cells assume a flattened, sessile phenotype whencultured on laminin but exhibit a more spreading, motile morphologywhen plated on fibronectin. In addition, numerous multinucleatedgiant cells are observed on a fibronectin substrate. Our datasuggest that the relative expression of laminin and fibronectinreceptors may determine the morphology and behaviour of trophoblastduring the process of implantation.     

Immunohistological distribution of the secretory endometrial protein, 'pregnancy-associated endometrial {alpha}2-globulin', a glycosylated {beta}-lactoglobulin homologue, in the human fetus and adult employing monoclonal antibodies

We have previously demonstrated that pregnancy-associated endometrial₂-globulin (₂-PEG), the human glycosylated (-lactoglobulin homologue(HG-BLG), is quantitatively the major secretory soluble proteinproduct of the secretory endometrium during the latter halfof the menstrual cycle and decidua spongiosa of the gestationalendometrium during early pregnancy, and is principally localizedto the glandular epithelium. In the present study employingmonoclonal antibodies in immunohistological techniques, thedistribution and localization has been examined in normal andpathological tissues of the adult and first-trimester fetus.No significant staining for ₂-PEG was detected in any non-reproduction-associatedtissue in the normal adult nor any tissue in the fetus. In theadult, most intense staining was associated with the endometrialglandular epithelium in the uterus or in ectopic sites in patientswith endometriosis. During the menstrual cycle and pregnancy,appearance of ₂-PEG in endometriosis was strongly linked withits appearance in uterine endometrial tissue, suggesting thatendometriotic tissue exhibited competence to respond to thesame hormonal milieu required to induce synthesis in the uterineendometrium. Localization to the mucosal epithelium of the Fallopiantube was consistent with synthesis of ₂-PEG, albeit at low levels,and staining at this site reflected fluctuations of stainingwithin the uterus. Of the pathological specimens examined, stainingwas only detected in a proportion of ovarian carcinomas. Nostaining was detected in the mammary gland, a site of -lactoglobulinsynthesis, whether obtained during pregnancy or lactation. Theseobservations support the proposal that during the menstrualcycle and pregnancy, the endometrial glandular epithelium representsthe major source of the glycosylated -lactoglobulin homologueand serum measurements may be employed to assess its functionalpresence. Mechanisms of regulation of its production that wouldaccount for the histological observations are discussed.     

Implantation: Tumour necrosis factor {alpha} inhibits in-vitro decidualization of human endometrial stromal cells

Interleukin-1 (IL-1) has been reported previously to inhibitthe in-vitro decidualization of human endometrial stromal cellsas assessed by progesterone-induced prolactin production andmorphological transformation. In this study we examined whetherother cytokines, such as tumour necrosis factor-(TNF), interferon-(IFN), IFN or granulocyte-macrophage colony-stimulating factor(GM-CSF), could affect the decidualization of human endometrialstromal cells in vitro. Of these cytokines, TNF significantlysuppressed prolactin production in a dose-dependent manner,with no apparent effect on cell number. The morphological transformationof endometrial stromal cells was also inhibited by TNF. TNFand IL-1 significantly suppressed cAMP-stimulated prolactinproduction by endometrial stromal cells. Neither the progesteroneconcentration in the supernatant of the endometrial stromalcell culture system nor intracellular calcium concentrationof the endometrial stromal cells were affected by the additionof TNF or IL-1. These results indicated that TNF and IL-1 suppressboth progesterone-induced and cAMP-mediated prolactin productionin endometrial stromal cells, and that this inhibition was notattributable to direct effects on progesterone metabolism orrelated to Ca2+-mediated signal transduction. These experimentssuggested that a local increase of TNF and IL-1 under certainpathological conditions in vivo may disturb blastocyst implantationand/or the maintenance of pregnancy by inhibiting the decidualizationof endometrial stromal cells.     

Integrins and adhesion molecules: A positive correlation between expression of {beta}1-integrin cell adhesion molecules and fertilizing ability of human spermatozoa in vitro

The purpose of this study was to investigate firstly whether(1-integrin cell adhesion molecules are expressed by human spermatozoa,and secondly whether there is any relationship between the expressionof 1-integrin cell adhesion molecules and the fertilizing abilityof human spermatozoa in vitro. A total of 50 semen samples wereexamined. The samples were obtained from the male partners ofcouples undergoing in-vitro fertilization (IVF) for either unexplained,tubal or male factor infertility. A panel of six monoclonalantibodies against 1-integrin cell adhesion molecules and immunohistochemicaltechniques were used to identify the presence of these moleculeson the spermatozoa. The percentage of spermatozoa showing strongimmunolabelling with each monoclonal antibody was assessed ineach sample. The relationship between these results and theaetiology of infertility and incidence of fertilization wasexamined. 1-Integrins, and primarily the ones with 4-, 5- and6-chains, were expressed by human spermatozoa. Compared withsemen samples from unexplained or male factor infertility patients,samples from tubal infertility patients had a significantlyhigher (P < 0.05) percentage of spermatozoa expressing adhesionmolecules. There was a positive correlation between the expressionof 4, 5 and a6 adhesion molecules and the fertilizing abilityof spermatozoa. The positive correlation between the presenceof certain (1-integrin cell adhesion molecules and the fertilizingability of human spermatozoa suggests that integrins may beputative determinants in egg-sperm recognition and interaction.     

Immunology: Autoimmunity to spermatozoa, asymptomatic Chlamydia trachomatis genital tract infection and {gamma}{delta} T lymphocytes in seminal fluid from the male partners of couples with unexplained infertility

The relationship between an undetected, asymptomatic Chlamydiatrachomatis genital tract infection, the concentration of andb T cells in semen and sperm autoimmunity was examined in 48male partners of couples with unexplained infertility. ImmunoglobulinA (IgA) antibodies to C.trachomatis were detected in seminalfluids from 14 (29.2%) of the men. Only four of these were positivefor circulating anti-chlamydial IgA, suggesting that the stimulusfor antibody production was within the genital tract. In contrast,four men were positive for anti-chlamydial IgG in their semen;all were also seropositive for anti-chlamydial IgG. T lymphocytesbearing the and antigen receptors were present in every semensample. Men with seminal anti-chlamydial IgA, however, had significantly(P = 0.035) elevated semen T cell concentrations (median 3100cells/ml) than did men lacking this antibody (median 1400 cells/ml);concentrations of T cells were comparable in both groups. Genitaltract sperm autoimmunity, as shown by antibodies bound to motileejaculated spermatozoa, was detected in 13 (27.1%) men. Thepresence of these antibodies was associated with elevated concentrationsof both (median 4200 versus 700 cells/ml) and (median 5000versus 850 cells/ml) T cells (P = 0.0002 and 0.0001 respectively).Men with antisperm antibodies only in their serum had seminalT cell concentrations comparable with men testing negative forantisperm antibodies. Anti-chlamydial IgA was identified insemen from four of 10 men with IgA bound to their spermatozoaand in none of the men with only spermatozoabound IgG. Therewas no relationship between sperm quality and the occurrenceof seminal IgA antibodies to either C.trachomatis or spermatozoa.An asymptomatic C.trachomatis infection activates T cells withinthe male genital tract, which may lead to antisperm antibodyformation and immune-mediated infertility.     

Integrins and adhesion molecules: Tumour necrosis factor-{alpha}-mediated dyscohesion of epithelial cells is associated with disordered expression of cadherin/{beta}-catenin and disassembly of actin filaments

Tumour necrosis factor (TNF)- induced, in a time- and dose-dependentfashion, dyscohesion (cell-cell dissociation) of the endometrialepithelial cells. TNF- impaired the ability of cells to aggregateand to attain compaction. The cell-cell adherent junction isa specialized region of the plasma membrane where cadherin moleculesact as adhesion molecules and actin filaments are densely associatedwith the plasma membrane through a well-developed plasmalemmalundercoat. Dyscohesion induced by TNF- was associated with thedisordered expression of cadherin\-catenin at the sites of cell-cellcontact. In addition, within the time-frame that dyscohesionwas induced, TNF- down-regulated the expression of actin mRNAonly at 100 ng/ml without modulating the overall amount of actinprotein, its -isoform or the amount of ribosylated actin. However,TNF--mediated dyscohesion of epithelial cells was associatedwith loss of plasmalemmal undercoat as well as intracytoplasmicaggregates of F-actin and a simultaneous increase in G-actin.The effect of cytochalasin-B, which disrupts actin filamentson cell-cell binding, was less pronounced than the effect ofTNF-, suggesting that the effect of this cytokine on dyscohesionis not solely dependent on the disassembly of actin filaments.These findings show that the induction of disordered expressionof adhesion molecules, as well as disassembly of actin filaments,are implicated in the dyscohesion induced by TNF-.     

Pregnancy: Cervical ripening with the cytokines interleukin 8, interleukin 1{beta} and tumour necrosis factor {alpha} in guinea-pigs

It has been suggested that the collagenolytic enzymes releasedfrom white blood cells which infiltrate the pregnant human uterinecervix at term are responsible for connective tissue changeswhich take place during the ripening process. Similarly, aninfiltration of inflammatory cells occurs in pregnant guinea-pigseither spontaneously at term or at preterm after treatment withthe antiprogestin onapristone. The objective of this study wasto evaluate the effects of the inflammatory cytokines interleukin8 (IL-8), interleukin 1 (IL-1), tumour necrosis factor (TNF-)and a combination of IL-1 and TNF- on cervical ripening in guinea-pigsduring advanced pregnancy. The cytokines were applied locally(intracervically) in a gel for 2 days and the effects were assessedon the third day by both extensibility measurements and morphologicalevaluation. IL-8 treatment on days 42 and 43 post coitum (p.c)and on days 48 and 49 p.c. (term: day 67± 3 p.c.) significantly(P < 0.05) increased cervical extensibility at both stagesof pregnancy. Although IL-1 treatment (days 42 and 43 p.c.)led to a slight increase in cervical extensibility, this effectwas not statistically significant. An electron microscope studyperformed on days 48 and 49 p.c. revealed a pronounced cervicalripening accompanied by the dissolution of collagen fibres,stromal oedema and the infiltration of polymorphonuclear leukocytesin all cytokine-treated groups. The morphological effects ofIL-8 and IL-1 were indistinguishable from those observed duringnormal cervical ripening at term. In contrast, TNF-, both aloneand in combination with IL-1, brought about a severe inflammatoryreaction with a massive infiltration of lymphocytes, marcophagesand polymorphonuclear leukocytes at the investigated dose. Weconclude that the local application of the inflammatory cytokinesIL-8, IL-1 and TNF- produces cervical ripening without inducinglabour in pregnant guinea-pigs; the morphological effects ofIL-8 and IL-1 being similar to the physiological cervical ripening.Our data support the view that cytokines, particularly IL-8,may play an important role during physiological, pathologicaland induced cervical ripening and could be clinically usefulas an adjunct to labour and delivery.     

Implantation: Impact of trophoblast penetration through the basal membrane on the efficacy of drug therapy in tubal pregnancies

Concentrations of -human chorionic gonadotrophin (HCG) of 2500IU/l are generally considered to be maximal for successful drugtherapy of tubal pregnancies [instillation of prostaglandin-F₂(PGF₂) or hyperosmolar glucose]. The purpose of our study wasto ascertain if there was an association between the significantlyhigher failure rates above this threshold value and the histologicallydetermined anatomopathological substratum. We therefore evaluatedthe impact of trophoblast penetration through the basal membraneof the Fallopian tube on the efficacy of drug therapy. Pre-operativeserum -HCG concentrations were compared with the histologicallydetermined trophoblast penetration, distinguishing between ectopicpregnancies with intra-luminal growths up to the myosalpinx,and those with extra-luminal growths going beyond the basalmembrane and penetrating the myosalpinx. Basic data were obtainedfrom a group of patients who received primary surgical treatmentbut it had never been the intention for them to receive drugtherapy (independently of their initial -HCG values; group I,n = 43). These reference data were compared with the findingsin preparations from another group of patients obtained duringsecondary surgical intervention, performed to achieve finalcure of tubal pregnancy after failure of primary PGF₂ instillation(group II, n = 30). Group I patients showed a significantlyhigher rate of intra-luminal trophoblast growths (P = 0.0001)at -HCG values <2500 IU/l; above this threshold value, extra-luminalspread was found significantly more often (P = 0.0001). In histologicalpreparations from group II, however, the number of extra-luminalgrowths was significantly higher even at low -HCG values (P= 0.007); at values above the threshold level, the distributionsin the two groups were similar. These results suggest that drugtherapy of tubal pregnancy becomes inefficient in tubal pregnanciesas soon as the trophoblast penetrates the basal membrane ofthe Fallopian tube.     

Physiology: Menstruation is associated with disordered expression of desmoplakin I/II and cadherin/catenins and conversion of F- to G-actin in endometrial epithelium

Endometrium is unique since it is the only tissue that undergoesregular cyclic bleedings. Menstrual shedding is associated withthe breakdown of endometrium, including the fragmentation ofendometrial glands. To gain insight into the underlying basisof fragmentation of the endometrial epithelium during the menstrualphase, we examined the expression of proteins implicated inepithelial cell—cell binding in human endometria throughoutthe entire menstrual cycle. Western blotting failed to revealdifferences in the relative amount of E-cadherin, - or -cateninor actin in the menstrual endometria compared with those inthe proliferative or secretory phases. However, specific changesin the expression pattern of these proteins as well as desmoplakinI/II were detected by immunohistochemical staining in epithelialcells of menstrual endometria. Desmoplakin I/II, E-cadherin,- and -catenins and -actin were localized to intercellular bordersas well as the luminal and basal regions of glandular epitheliumduring the proliferative and secretory phases. Immunoreactivityof E-cadherin and -catenin was confined to epithelial cells,whereas -catenin and -actin were present in epithelial cells,as well as in stroma and endothelial cells. Binding of F-actinto fluorescein isothiocyanate-labelled phalloidin localizedthis form of actin to the intercellular borders, and the basaland luminal cytoplasm of epithelial cells in proliferative andsecretory endometria. Menstrual shedding was associated withdisorganization of the site-specific distribution of desmoplakinI/II, E-cadherin and - and -catenins. This included focal patchyexpression of these proteins or their total loss from cell—cellbinding sites, as well as loss of F-actin in epithelial cellsof menstrual endometrial glands. However, these changes werenot observed in the basalis region that is not shed during themenstrual phase. These findings suggest that fragmentation ofthe endometrial glands during the menstrual phase is relatedto the disorganization and/or loss of the proteins at the adherensand desmosomal junctions, as well as loss of F-actin.     

Endocrinology: The effect of antiprogestin (RU 486) and prostaglandin biosynthesis inhibitor (naproxen) on uterine fluid prostaglandin F2{alpha} concentrations

In the present study the effect of the antiprogestin RU 486and the prostaglandin biosynthesis inhibitor, naproxen, on uterinefluid concentration of prostaglandin F₂ (PGF₂) was investigated.RU 486, 200 mg, was administered two days after the luteinizinghormone (LH) surge and naproxen, 500 mg, was given every 12thhour five times starting 4 days after the LH surge. Uterinefluid was collected in the proliferative phase at ovulationand in the mid-luteal phase in a control and treatment cycle.The amount of PGF₂ was measured by gas chromatography-mass spectrometry.In the control cycle, the highest concentration of PGF₂ wasfound in the mid-luteal phase, and the lowest at the time ofovulation. Both RU 486 and naproxen reduced the PGF₂ concentrationin uterine fluid considerably, or to 22–25% of that inthe control cycle at the time of implantation. PGF₂ producedby the endometrium is believed to be of importance for the implantationof the blastocyst. Post-ovulatory treatment with RU 486 effectivelyprevents implantation, probably mainly by inhibiting the maturationof the endometrium during the secretory phase of the cycle.It is suggested that the inhibition of PGF₂ release throughthe uterine fluid caused by RU 486 may also be of importance.     

Integrins and adhesion molecules: Gelatinase and oncofetal fibronectin secretion is dependent on integrin expression on human cytotrophoblasts

Collagenolytic activity of cytotrophoblasts is stimulated byglycoproteins of the extracellular matrix and since this stimulationcan possibly occur through integrins, we measured the gelatinolyticactivity of villous and extravillous cytotrophoblasts accordingto the type of integrins expressed on these cells. Cytotrophoblastswere isolated from legal abortions, immunopurified with anti-CD45,separated according to their expression of histocompatibility-linkedantigen (HLA)-G, ₆ or ₅ integrin subunits and cultured for 5days on plastic or agarose. Fetal fibronectin, human chorionicgonadotrophin (HCG) and the gelatinolytic activity were measuredin the culture supernatants. Following immunopurification withanti-CD45, the gelatinolytic activity of cytotrophoblasts wassignificantly higher than before, indicating that contaminatinglymphomyeloid cells secreted gelatinolytic inhibitors. HLA-Gpositive cells secreted significantly more gelatinases thanHLA-G negative cells but their HCG secretion was similar. Comparedto ₅ positive cells, ₆ positive cytotrophoblasts secreted significantlymore gelatinases, significantly less fibronectin but similaramounts of HCG. We conclude that during trophoblast invasion,extravillous cytotrophoblasts (HLA-G positive) expressing the₆ integrin subunit represent the invasive population of cells(high gelatinase and low fibronectin secretion). When expressionof the ₅ integrin subunit is turned on, their invasive behaviourceases and they secrete low amounts of gelatinases and highconcentrations of fibronectin.