{"id":6,"date":"2022-09-11T08:16:00","date_gmt":"2022-09-11T08:16:00","guid":{"rendered":""},"modified":"2023-02-01T12:32:22","modified_gmt":"2023-02-01T12:32:22","slug":"tout-savoir-sur-les-plaquettes-sanguines","status":"publish","type":"post","link":"https:\/\/avo6.com\/?p=6","title":{"rendered":"Plaquettes Sanguines : R\u00f4le et Exploration Biologique"},"content":{"rendered":"<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><a href=\"https:\/\/avo6.com\/wp-content\/uploads\/2022\/09\/les-20plaquettes-20sanguines.jpg\"><img src=\"https:\/\/avo6.com\/wp-content\/uploads\/2022\/09\/les-20plaquettes-20sanguines-300x257.jpg\" alt=\"Les plaquettes Sanguines\"\/><\/a><\/figure><\/div>\n\n\n<div class=\"wp-block-aioseo-table-of-contents\"><ul><li><a href=\"#aioseo-i-introduction\">I. INTRODUCTION\u00a0:<\/a><\/li><li><a href=\"#aioseo-ii-morphologie\">II. MORPHOLOGIE\u00a0:<\/a><ul><li><a href=\"#aioseo-a-microscope-optique\">A. Microscope optique<\/a><\/li><li><a href=\"#aioseo-b-microscope-a-contraste-de-phase\">B. Microscope a contraste de phase<\/a><\/li><li><a href=\"#aioseo-c-microscope-electronique\">C. Microscope \u00e9lectronique<\/a><\/li><\/ul><\/li><li><a href=\"#aioseo-3-fonctions\">3. FONCTIONS\u00a0:<\/a><ul><li><a href=\"#aioseo-a-hemostase-primaire-et-coagulation\">A. H\u00e9mostase primaire et coagulation\u00a0:<\/a><\/li><\/ul><\/li><li><a href=\"#aioseo-b-inflammation\">B. Inflammation\u00a0:<\/a><\/li><li><a href=\"#aioseo-c-conflits-ag-ac\">C. Conflits Ag-Ac\u00a0:<\/a><\/li><li><a href=\"#aioseo-d-lutte-antiparasitaire\">D. Lutte antiparasitaire:<\/a><\/li><li><a href=\"#aioseo-4-exploration-et-pathologie\">4. EXPLORATION ET PATHOLOGIE\u00a0:<\/a><\/li><li><a href=\"#aioseo-a-numeration-des-plaquettes\">A. Num\u00e9ration des plaquettes\u00a0:<\/a><\/li><li><a href=\"#aioseo-b-myelogramme\">B. My\u00e9logramme\u00a0:<\/a><\/li><li><a href=\"#aioseo-c-etude-des-fonctions-plaquettaires\">C. Etude des fonctions plaquettaires\u00a0:<\/a><\/li><li><a href=\"#aioseo-d-autres-techniques\">D. Autres techniques\u00a0:<\/a><\/li><\/ul><\/div>\n\n\n\n<h3 id=\"aioseo-i-introduction\">\u00a0I. INTRODUCTION\u00a0:<\/h3>\n\n\n\n<p>Les plaquettes sanguines sont des cellules anucl\u00e9\u00e9es, disco\u00efdes provenant des m\u00e9gacaryocytes.<\/p>\n\n\n\n<p>Valeur Normale : 150-450 G \/L. 30% sont s\u00e9questr\u00e9es de mani\u00e8re r\u00e9versible dans la rate.<\/p>\n\n\n\n<h3 id=\"aioseo-ii-morphologie\">II. MORPHOLOGIE\u00a0:<\/h3>\n\n\n\n<h4 id=\"aioseo-a-microscope-optique\">A. Microscope optique<\/h4>\n\n\n\n<p>Fragments de cytoplasme anucl\u00e9\u00e9s, arrondis ou ovalaires, de 2-3 Um de diam\u00e8tre.<\/p>\n\n\n\n<p>Le cytoplasme est clair et l\u00e9g\u00e8rement basophile.<\/p>\n\n\n\n<p>Au MGG\u00a0: Il Ya deux\u00a0\u00a0zones\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n\n\n\n<p>\u00a0\u00a0\u00a0<strong>Chromom\u00e8re\u00a0<\/strong>: zone centrale\u00a0; avec des grains rouge violet<\/p>\n\n\n\n<p>\u00a0\u00a0\u00a0<strong>Hyalom\u00e8re<\/strong>\u00a0:\u00a0\u00a0\u00a0zone p\u00e9riph\u00e9rique faiblement basophile<\/p>\n\n\n\n<h4 id=\"aioseo-b-microscope-a-contraste-de-phase\">B. Microscope a contraste de phase<\/h4>\n\n\n\n<p>&nbsp;Elle apparait disco\u00efde avec des prolongements de longueur croissante<\/p>\n\n\n\n<h4 id=\"aioseo-c-microscope-electronique\">C. Microscope \u00e9lectronique\u00a0<\/h4>\n\n\n\n<p><strong>\u00a0<\/strong>On trouve 3 Zones principales<\/p>\n\n\n\n<p><strong><u>a-Zone p\u00e9riph\u00e9rique<\/u>\u00a0:\u00a0<\/strong><\/p>\n\n\n\n<p>Comprend 3 Zones\u00a0:<\/p>\n\n\n\n<p><strong><u>b.1-Mb plaquettaire<\/u><\/strong>\u00a0: <\/p>\n\n\n\n<p>Double couche de phospholipides et de glycoprot\u00e9ines.<\/p>\n\n\n\n<ul><li>Phospholipides&nbsp;: ont une asym\u00e9trie de membrane&nbsp;:<\/li><\/ul>\n\n\n\n<p>&nbsp;Feuillet externe&nbsp;: choline phospholipidique<\/p>\n\n\n\n<p>&nbsp;Feuillet interne&nbsp;: aminophospholipidique<\/p>\n\n\n\n<p>Les fonctions des phospholipides&nbsp;:<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pr\u00e9curseurs de la voie de la prostaglandine<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pr\u00e9curseurs du PAF (platelet active factor)<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pr\u00e9curseurs des messagers du m\u00e9tabolisme plaquettaire<\/p>\n\n\n\n<ul><li>Glycoprot\u00e9ine&nbsp;: D\u00e9pend du stade d\u2018activation<\/li><\/ul>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;GP Ib&nbsp;: sialoglycoprot\u00e9ine majeure de la membrane<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;GP IIb-IIIa&nbsp;: ces 2 GP forment un complexe qui sert de r\u00e9cepteur au fibrinog\u00e8ne et&nbsp;&nbsp;aussi au FVW et \u00e0 la fibronectine.<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GP V&nbsp;: r\u00e9cepteur a la thrombine<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GP IV&nbsp;: re\u00e7oit la thrombospondine<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prot\u00e9ine G&nbsp;: Gs&nbsp;: Stimulatrice&nbsp;&nbsp;&nbsp;Gi&nbsp;: Inhibitrice&nbsp;&nbsp;&nbsp;Go&nbsp;: variable<\/p>\n\n\n\n<p><strong><u>a.2-Syst\u00e8me canalaire ouvert (SCO)<\/u>:<\/strong>\u00a0<\/p>\n\n\n\n<p>Lieu de la s\u00e9cr\u00e9tion des granules plaquettaires et du passage des substances plasmatiques vers les plaquettes.<\/p>\n\n\n\n<p><strong><u>a.3-Syst\u00e8me tubulaire dense (STD<\/u><\/strong>)\u00a0:\u00a0<\/p>\n\n\n\n<p>Lieu de stockage du Ca (Calcium) qui active le syst\u00e8me contractile de la plaquette.<\/p>\n\n\n\n<p><strong><u>b-Cytosquelette&nbsp;:&nbsp;<\/u><\/strong>Constitue de&nbsp;:<\/p>\n\n\n\n<ul><li>Microtubules&nbsp;: maintien la forme disco\u00efde des plaquettes.<\/li><li>Actomyosine plaquettaire&nbsp;: activit\u00e9 contractile<\/li><li>Prot\u00e9ines contractiles&nbsp;: maintien de la forme disco\u00efde des plaquettes et la contraction et la s\u00e9cr\u00e9tion du contenu des granules intra-plaquettaires apr\u00e8s le signal d\u2019activation.<\/li><\/ul>\n\n\n\n<p><strong><u>c-Zone&nbsp;d\u2019organelles:&nbsp;<\/u><\/strong>Constitu\u00e9e de l\u2019appareil de golgi, mitochondries, des grains de glycog\u00e8ne (grains denses, grains alpha, lysosomes, microperoxysomes.<\/p>\n\n\n\n<h3 id=\"aioseo-3-fonctions\"><strong>3. FONCTIONS&nbsp;:<\/strong><\/h3>\n\n\n\n<h4 id=\"aioseo-a-hemostase-primaire-et-coagulation\"><strong>A. H\u00e9mostase primaire et coagulation&nbsp;:<\/strong><\/h4>\n\n\n\n<ul><li><strong><u>Adh\u00e9sion plaquettaire<\/u><\/strong>\u00a0: L\u00e9sion endoth\u00e9liale\u00a0<strong>&#8212;)<\/strong>\u00a0adh\u00e9sion plaquettaire.<\/li><\/ul>\n\n\n\n<p>Le FVW se lie GP Ib-IX&nbsp;<strong>&#8212;&gt;<\/strong>&nbsp;activation des filaments d\u2019actine<strong>&nbsp;&#8212;&gt;<\/strong>&nbsp;contraction des plaquettes<\/p>\n\n\n\n<ul><li><strong><u>Activation plaquettaire<\/u><\/strong>&nbsp;: A l\u2019\u00e9tat activ\u00e9 la plaquette change de forme et devient sph\u00e9rique sous l\u2019action de plusieurs ph\u00e9nom\u00e8nes (ADP, thrombine,\u2026).Ces modification morphologiques sont support\u00e9es par des r\u00e9actions biochimiques tr\u00e8s pr\u00e9coces&nbsp;: ph\u00e9nom\u00e8nes de transduction du signal. 3 voies participent \u00e0 la transduction&nbsp;:<\/li><\/ul>\n\n\n\n<p>\u00fc&nbsp;&nbsp;Voie des phospholipases C (PLC)&nbsp;: phosphoinositides &#8212;&#8212;&gt; IP3 + DAG<\/p>\n\n\n\n<p>\u00fc\u00a0\u00a0Voie des tyrosines kinases\u00a0: La stimulation des Plaquettes => activation de tyrosines kinases ==> phosphorylation des prot\u00e9ines sur les r\u00e9sidus tyrosine. Ces prot\u00e9ines ont un r\u00f4le dans l\u2019agr\u00e9gation plaquettaire.<\/p>\n\n\n\n<p>\u00fc&nbsp;&nbsp;Voie de la PI3 Kinase&nbsp;: phosphatidyl inositol 3 Kinase<\/p>\n\n\n\n<ul><li><strong><u>S\u00e9cr\u00e9tion plaquettaire<\/u><\/strong>&nbsp;: Fusion de&nbsp;&nbsp;la membrane cytosolique et celle des grains alpha avec le SCO.<\/li><li><strong><u>Les activit\u00e9s pro-coagulantes<\/u><\/strong>&nbsp;: A la surface des PLQ activ\u00e9es s\u2019exprime des v\u00e9sicules de PLQ&nbsp;&nbsp;&#8212;&gt; attraction des prot\u00e9ines de la coagulation &#8212;-&gt; g\u00e9n\u00e9ration de la thrombine.<\/li><\/ul>\n\n\n\n<h3 id=\"aioseo-b-inflammation\"><strong>B. Inflammation&nbsp;:<\/strong><\/h3>\n\n\n\n<p>S\u00e9cr\u00e9tion de facteurs de perm\u00e9abilit\u00e9 vasculaire.<\/p>\n\n\n\n<h3 id=\"aioseo-c-conflits-ag-ac\"><strong>C. Conflits Ag-Ac&nbsp;:<\/strong><\/h3>\n\n\n\n<p><strong><u>&nbsp;<\/u><\/strong>Complexe Ag(Antig\u00e8ne)-Ac (Anticorps) active les plaquettes.<\/p>\n\n\n\n<h3 id=\"aioseo-d-lutte-antiparasitaire\">D.<strong> Lutte antiparasitaire:&nbsp;<\/strong><\/h3>\n\n\n\n<p>L<strong>\u2019<\/strong>activit\u00e9 phagocytaire des PLQ vis-\u00e0-vis des parasites est due \u00e0 la fixation des IgE&nbsp;&nbsp;aux complexes GP IIb-IIIa.<\/p>\n\n\n\n<h3 id=\"aioseo-4-exploration-et-pathologie\"><strong>4. EXPLORATION ET PATHOLOGIE&nbsp;:<\/strong><\/h3>\n\n\n\n<h3 id=\"aioseo-a-numeration-des-plaquettes\"><strong>A. Num\u00e9ration des plaquettes&nbsp;:<\/strong>&nbsp;<\/h3>\n\n\n\n<p>Se fait par technique manuelle ou automatique<\/p>\n\n\n\n<p>VN&nbsp;: 150-400 G\/L<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Thrombop\u00e9nie : Taux de PLQ &lt; 150 G&nbsp;\/l<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Thrombocytose&nbsp;: Taux de PLQ &gt;500 G\/l.<\/p>\n\n\n\n<h3 id=\"aioseo-b-myelogramme\"><strong><a href=\"https:\/\/avo6.com\/?p=635\">B. My\u00e9logramme\u00a0:<\/a><\/strong><\/h3>\n\n\n\n<p>Donne une estimation de la pr\u00e9sence des m\u00e9gacaryocytes dans la Moelle Osseuse.<\/p>\n\n\n\n<p>En cas de thrombop\u00e9nie il permet de distinguer entre l\u2019origine p\u00e9riph\u00e9rique et centrale&nbsp;:<\/p>\n\n\n\n<ul><li>D\u2019origine p\u00e9riph\u00e9rique&nbsp;: anomalie de r\u00e9partition (hyperspl\u00e9nisme), hyperconsommation (CIVD), m\u00e9canisme immunologique (PTI).<\/li><li>D\u2019origine centrale&nbsp;:<\/li><\/ul>\n\n\n\n<p>o&nbsp;&nbsp;&nbsp;Constitutionnelle&nbsp;: thrombopathie, maladie de Bernard et Soulier.<\/p>\n\n\n\n<p>o&nbsp;&nbsp;&nbsp;Acquise&nbsp;: PTAI, aplasie m\u00e9dullaire.<\/p>\n\n\n\n<h3 id=\"aioseo-c-etude-des-fonctions-plaquettaires\"><strong>C. Etude des fonctions plaquettaires&nbsp;:<\/strong><\/h3>\n\n\n\n<ul><li>Adh\u00e9sion plaquettaire&nbsp;: explor\u00e9 in vivo par la technique de <a href=\"https:\/\/fr.wikipedia.org\/wiki\/Carsten_Borchgrevink\">Borchgrevink<\/a>&nbsp;: on pratique un Temps de Saignement&nbsp;&nbsp;selon la m\u00e9thode d\u2019Ivy incision.<\/li><li>Agr\u00e9gation plaquettaire&nbsp;: par photom\u00e9trie sur plasma riche en PLQ. Faire agr\u00e9ger les PLQ en pr\u00e9sences d\u2019agoniste tel que l\u2019ADP, collag\u00e8ne\u2026.<\/li><li>Les principales anomalies de l\u2019adh\u00e9sion et de l\u2019agr\u00e9gation plaquettaire&nbsp;:<\/li><\/ul>\n\n\n\n<p>Thrombopathies constitutionnelles (Glanzman, Bernard soulier)<\/p>\n\n\n\n<p>Thrombopathie acquise (m\u00e9dicamenteuse&nbsp;: aspirine, m\u00e9tabolique&nbsp;: IR, h\u00e9matologique SMP)<\/p>\n\n\n\n<h3 id=\"aioseo-d-autres-techniques\"><strong>D. Autres techniques&nbsp;:<\/strong><\/h3>\n\n\n\n<p>Cytom\u00e9trie en flux.<\/p>\n\n\n\n<p>Etude de la s\u00e9cr\u00e9tion Plaqu\u00e9taire par ELISA.<\/p>\n\n\n\n<p>Etude du m\u00e9tabolisme..<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Les plaquettes sanguines sont des cellules anucl\u00e9\u00e9es, disco\u00efdes provenant des m\u00e9gacaryocytes.<br \/>\nTaux :150-450 G \/L. 30% sont s\u00e9questr\u00e9es  dans la rate<\/p>\n","protected":false},"author":2,"featured_media":109,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0},"categories":[2],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/6"}],"collection":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6"}],"version-history":[{"count":6,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/6\/revisions"}],"predecessor-version":[{"id":702,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/6\/revisions\/702"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/media\/109"}],"wp:attachment":[{"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}