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Alterations in the adhesive and degradative properties of trophoblast cells isolated from preeclamptic placentas
A.22
Placenta (1995), Vo116
Elastic fibres are an essential component of human placental stem villous stroma and an inter]rated part of the perivascular contractile sheath. R. Graf~, H Neudeck1, R. Gossrau 1, M. Nierhaus 2 K. Vetter2 1Dept. of Anatomy, UnJvers~t~tsklinJkumBenjamin Franklin, Freie Universitat Berlin, 2Dept. Obstet. and Gynecol., Krankenhaus NeukOlln, Berhn, Germany Currently it is believed that the stroma of human placental stem villi consists only of reticular and collagen fibres. In the present study we were able to show for the first time by electron and light microscopy (orcein staining) large amounts of elastic fibres in the stem villous stroma. Electron microscopically homogeneous elastin was found alone or in association to microfibrils, or microfibrils wtthout or with poor shares of elastm were forming long bands. These three structures, generally known to form elastic connective ttssue, were seen in close connection to placental extravascular smooth muscle cells whtch belong to the penvascular contractile sheath of stem wlh ElastJn was associated to these smooth muscle cells and was connected to collagen fibres via microfibnls Collagen fibres were, Jn additton also connected to each other by splke-hke structures. Extravascular smooth muscle cells revealed numerous adhesion plaques whtch occupied conspicuous long cytoplasmic faces of the plasma membrane In cryostat sections, tmmunoreactlvity of tahn, an attachment protein of adhesion plaques which links mtracellular ct-actm filaments with extracellular fibronectm, was detected in extravascular and vascular (media) smooth muscle cells Fibronectin-immunoreactivity was localized correspondingly. The arrangement of placental extravascular smooth muscle cells, elastic and collagen fibres suggests a functional myofibroelastic unit within the penvascular contractile sheath, surrounding the large fetal blood vessels, which may contribute to elasticity and support tensile and/or contracting forces within these stem vdli Supported by the Deutsche ForschungsgemeJnschaft (Sfb 174).
ALTERATIONS IN THE ADHESIVE AND DEGRADATIVE PROPERTIES OF TROPHOBLAST CELLS ISOLATED FROM PREECLAMPTIC PLACENTAS. C H Graham, Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 Preeclampsia is a condationcharacterized by shallow trophoblastic invasion of the uterine spiral arteries The present study examined whether trophoblasts isolated from preeclamptic (PE) placentas exhibit alterations in their in vitro adhesive and degradative properties as compared with trophoblasts isolated from normal placentas. Third trimester normal and PE trophoblasts were isolated and cultured by the method of Yui et al (Placenta 15 231, 1994) In vitro invasweness and adhesiveness were examined by means of Matrigel (MG) invasion and adhesion assays Gelatinase secretion was determined by protein zymography and soluble urokmase (uPA) activity was determined by a biochemical colorimetric assay (Karlan et aL Biochem. Biophys Res. Commun 142:147, 1987). Preliminary results revealed that, compared wath normal trophoblasts, PE cells exhibited reduced m vitro invasiveness and reduced adhesion to MG. Protein zymography showed that cultured normal and PE cells secreted variable levels of gelatmase, of which the most predorrunant was gelatmase B (MMP-9) This gelatmase, however, was of slightly higher molecular weight m the media conchtioned by preeclamptic ceils, possibly representing the latent, progelatmase form. Available secreted urokinase (uPA) activity was also reduced in PE cell cultures. These results suggest that poor trophoblastic invasion in preeclampsia might be due to reduced adhesiveness to extracellular matrix molecules as well as reduced levels of active proteinases essential for invasion. Other hemodynamic changes occurring in preeelampsia (e.g. fibrin clots in the intervillous spaces) might also be due to reduced uPA secretion. (Supported by the J.P. Bickell Foundation and the Ontario Heart and Stroke Foundation).
Placenta (1995), Vo116
Elastic fibres are an essential component of human placental stem villous stroma and an inter]rated part of the perivascular contractile sheath. R. Graf~, H Neudeck1, R. Gossrau 1, M. Nierhaus 2 K. Vetter2 1Dept. of Anatomy, UnJvers~t~tsklinJkumBenjamin Franklin, Freie Universitat Berlin, 2Dept. Obstet. and Gynecol., Krankenhaus NeukOlln, Berhn, Germany Currently it is believed that the stroma of human placental stem villi consists only of reticular and collagen fibres. In the present study we were able to show for the first time by electron and light microscopy (orcein staining) large amounts of elastic fibres in the stem villous stroma. Electron microscopically homogeneous elastin was found alone or in association to microfibrils, or microfibrils wtthout or with poor shares of elastm were forming long bands. These three structures, generally known to form elastic connective ttssue, were seen in close connection to placental extravascular smooth muscle cells whtch belong to the penvascular contractile sheath of stem wlh ElastJn was associated to these smooth muscle cells and was connected to collagen fibres via microfibnls Collagen fibres were, Jn additton also connected to each other by splke-hke structures. Extravascular smooth muscle cells revealed numerous adhesion plaques whtch occupied conspicuous long cytoplasmic faces of the plasma membrane In cryostat sections, tmmunoreactlvity of tahn, an attachment protein of adhesion plaques which links mtracellular ct-actm filaments with extracellular fibronectm, was detected in extravascular and vascular (media) smooth muscle cells Fibronectin-immunoreactivity was localized correspondingly. The arrangement of placental extravascular smooth muscle cells, elastic and collagen fibres suggests a functional myofibroelastic unit within the penvascular contractile sheath, surrounding the large fetal blood vessels, which may contribute to elasticity and support tensile and/or contracting forces within these stem vdli Supported by the Deutsche ForschungsgemeJnschaft (Sfb 174).
ALTERATIONS IN THE ADHESIVE AND DEGRADATIVE PROPERTIES OF TROPHOBLAST CELLS ISOLATED FROM PREECLAMPTIC PLACENTAS. C H Graham, Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 Preeclampsia is a condationcharacterized by shallow trophoblastic invasion of the uterine spiral arteries The present study examined whether trophoblasts isolated from preeclamptic (PE) placentas exhibit alterations in their in vitro adhesive and degradative properties as compared with trophoblasts isolated from normal placentas. Third trimester normal and PE trophoblasts were isolated and cultured by the method of Yui et al (Placenta 15 231, 1994) In vitro invasweness and adhesiveness were examined by means of Matrigel (MG) invasion and adhesion assays Gelatinase secretion was determined by protein zymography and soluble urokmase (uPA) activity was determined by a biochemical colorimetric assay (Karlan et aL Biochem. Biophys Res. Commun 142:147, 1987). Preliminary results revealed that, compared wath normal trophoblasts, PE cells exhibited reduced m vitro invasiveness and reduced adhesion to MG. Protein zymography showed that cultured normal and PE cells secreted variable levels of gelatmase, of which the most predorrunant was gelatmase B (MMP-9) This gelatmase, however, was of slightly higher molecular weight m the media conchtioned by preeclamptic ceils, possibly representing the latent, progelatmase form. Available secreted urokinase (uPA) activity was also reduced in PE cell cultures. These results suggest that poor trophoblastic invasion in preeclampsia might be due to reduced adhesiveness to extracellular matrix molecules as well as reduced levels of active proteinases essential for invasion. Other hemodynamic changes occurring in preeelampsia (e.g. fibrin clots in the intervillous spaces) might also be due to reduced uPA secretion. (Supported by the J.P. Bickell Foundation and the Ontario Heart and Stroke Foundation).