批发和零售贸易零售业课件

Hemostasis/CoagulationGregoryS.Travlos,DVM,DACVPNationalInstituteofEnvironmentalHealthSciencesResearchTrianglePark,NC27709919-541-0653Travlos@Hemostasis/CoagulationGregoryHemostasisTheprocessbywhichbleedingisarrested.ItisaseriesofphysiologicalandbiochemicaleventswhichterminateintheformationofaninsolublefibrinclotHemostaticSequence:InteractionbetweenvesselwallandplateletsBloodcoagulationFibrinolysisHemostasisTheprocessbywhich2HemostaticComponentInteractionsThompson&Harker,1983HemostaticComponentInteracti3BloodVesselsIntactendotheliumformsathromboresistantsurface

Requiredforthefreeflowofblood;doesnotpromoteplateletadherenceoractivatecoagulationPassivemechanisms:Endothelialglycocalyx(negativecharge-repelslike-chargedparticles,e.g.,platelets).Presenceofa2-macroglobulinatcellsurface(proteaseinhibitor).Activemechanisms:Endothelialcellsremoveplateletaggregationpromotersfromcirculation(e.g.,PGF1,bradykinin,serotonin,adeninenucleotides).SecretionofPGI2-potentinhibitorofplateletaggregation,inducesvasodilation.Proteoglycanmatrixofthevesselwallinfluencesthrombogenicity.Heparin,heparansulfateanddermatansulfatehaveanticoagulantactivity;otherglycosaminoglycansandhyaluronicaciddonot.Veinshavethehighestconcentration.BloodVesselsIntactendotheliu4EndotheliumBesidestheirroleinthromboresistance,endothelialcellshaveadditionalsyntheticfunctions.ProduceVonWillebrand’sfactorAbsorbedbyplatelets;neededforadherencetocollagenProduceplasminogenactivator(tPA)MediatesfibinolysisInjuredcellsreleasethromboplastin(factorIII)Activatesthe“extrinsic”coagulationcascadeOthers(e.g.,typeIIIandIVcollagens,elastin,fibronectin,etc.)EndotheliumBesidestheirrole5BloodVesselStructureThompson&Harker,1983BloodVesselStructureThompson6PlateletsAdheretoexposedcollagen(plateletplug)Occursinseconds;cancontrolhemorrhageofminuteinjuriesSecretoryfunctions;mediatorsofcoagulationandfibrinolysisReleasesADP;stickyandpromotesplateletadherenceADPactivatesphospholipaseA2whichstimulatesthromboxaneA2synthesisReleaseofmembranefibrinogen,factorV,factorVIIIandcalciumReleaseofmembraneplateletphospholipid.PlateletsAdheretoexposedcol7Platelet-TEMmitochodrionmicrotublulesOCSgranulesPlatelet-TEMmitochodrionmicr8UltrastructuralandFunctionalPlateletAnatomyUltrastructuralandFunctional9Platelets-cont.Theroleofplateletsinhemostasisisasimportantasthecoagulationmechanism.Thrombocytopenia,thrombastheniaorthromobopathia-impairhemostasisThrombocytosisorthrombocythemia-mayimpair,butusuallypromotesclotting(predisposestothrombosis).Plateletspromotehemostasisby:ReleaseofADPandotheragonists;promotesadherence.ADPactivatesphospholipaseA2whichstimulatesthromboxaneA2synthesisThromboxaneA2-stimulatesvasoconstrictionandplateletaggregationReleaseofmembranefibrinogen,factorV,factorVIIIandcalciumComponentsofcoagulationlocalizedatsiteofinjuryReleaseofmembraneplateletphospholipid.Acceleratesthe“intrinsic”and“common”pathwaysofcoagulationPlatelets-cont.Theroleofp10ProstaglandinMetabolismHarlan&Harker,1981ProstaglandinMetabolismHarlan11HemostaticPlateletFunctionsThompson&Harker,1983HemostaticPlateletFunctionsT12PlateletResponseWhenavesselisinjuredorseveredabrief,local,reflexvasoconstrictionoccurs.

Reducesbloodflowatsite.Maintainedbyvasoactivecompounds(platelets,surroundingtissues).

Passingplateletsadheretoexposedcollagen.Occursinseconds;initiallyadhereinasinglelayerandbecomeactivated.Severeinjury-collagenservesasapotentplateletactivator.Lesssevereinjury-vWFandfibrinogenbecomethemajoractivators.Theadheredplateletsundergoaconformationalchange.Fromdiscoidtodevelopmentoflongfilopodia.ActivationofGPreceptorsforfibrinogenand/orvWF(GPIIb/IIIaandGPIb/IX/V).PlateletResponseWhenavessel13StructureoftheGPIb-IX-VreceptorTablin,2000StructureoftheGPIb-IX-Vrec14PlateletResponsetoAgonistsPlatelets-unstimulatedAdditionofADP(mildstimulation)Additionofthrombin(strongstimulation)CharacteristicdiscoidshapeShapechange(elongationandcrescents)andfilaformprocessformation(arrows)Increasedspreading,filaformprocessextension(arrows)andaggregateformation(stars)SEMplates;Gentry,2000PlateletResponsetoAgonistsP15PlateletResponsecont.Activatedplateletsreleasetheira-granuleanddensebodycontentsinducingadditionalplateletrecruitment.

Densegranules-ADP,serotoninandepinephrine.alpha-granules-fibrinogen(andvWFinhumanandpig).SynthesisandreleaseofPAFandTxA2.Theagonistsacceleratethedevelopmentofanirreversibleplateletaggregate(plateletplug).Reversiblev.irreversibleresponses.ThrombocytesofbirdsandreptilesdonotrespondtoADP.Serotoninandepinephrine:Serotonin-shapechange(rat,g.piganddog);aggregation(human,rabbit,cow,horse,pig,sheepandcat).Epinephrine-onlyhuman,primate,catandhorseplateletsappearresponsive.Eitherserotoninorepinephrinecombinedwithanotheragonist-strongresponseinallspecies.PlateletResponsecont.Activat16PlateletResponsecont.Moreaboutagonists.

PlateletActivatingFactor(PAF).Cow,horse,sheep,primate,dog,g.pigandrabbitrespondtoPAF.Humanlesssensitiveandratandmouseareinsensitivetothisagonist.ThromboxaneA2(TxA2).Strongagonist-human,

g.pigandrabbit.Weakagonist-horse.Insensitive-rat,cow,pig.Inreallife,however,plateletsareexposedtomultipleagonistsfromplateletsandothercells(e.g.,redcells,ADP;whitecells,PAF).PlateletResponsecont.Moreab17PlateletAggregationtoThrombinHarlan&Harker,1981PlateletAggregationtoThromb18HemostaticPlugFormationBaumgartner&Muggli,1980HemostaticPlugFormationBaumg19CoagulationSystemConsistsofacascadingsystemofproteinsPrimarilyoriginatingfromliver(exceptfactorIII)Circulateininactiveform(except,possibly,factorVII)Systemincludes:EnzymaticfactorsNon-enzymaticfactorsTissuethromboplastin(factorIII)Calcium(factorIV)Plateletphospholipid(PF3)-structuralcomponent;acceleratesfactoractivationAnticoagulantfactorsThecoagulationsystemconsistsofthreepathways(intrinsic,extrinsicandcommon)CoagulationSystemConsistsof20批发和零售贸易零售业课件21ProcoagulantFactorsProcoagulantFactors22CoagulationSystems-cont.EnzymaticfactorsCirculateasnon-activezymogens-mustbeactivatedtofunctionActivatedenzymaticfactorsarenotconsumedduringclotting(exceptfactorsIIandXIII)PartialdeficiencyresultsinpartiallossofclottingabilityActivatedenzymaticfactorsinhibitedbyantithrombinIII(complexedwithheparin)andsomealpha-2-glycoproteinsEnzymaticfactors:XIandXII(contactfactors)II,VII,IXandX(vitaminK-dependentfactors)XIII(clotstabilizingfactororfibrin-stabilizingfactor)CoagulationSystems-cont.Enz23CoagulationSystems-cont.Non-enzymaticfactorsOriginatefromliverbutassociatewithplateletmembranes(alsofoundinplasma)Normalclottingwithpartialdeficiency;almosttotalabsenceneededtoaffecthemostasisorclottingClottingconsumesthesefactors-absentinserumNoknownnaturalinhibitorsConsideredreactiveproteins-increasedduringinflammatoryandneoplasticprocesses(exceptfactorIII)Non-enzymaticfactors:Fibrinogen(factorI)FactorVFactorVIII:C(associatedwithVonWillebrand’sfactor)CoagulationSystems-cont.Non24CoagulationCascadeInteractionsCoagulationCascadeInteractio25DoesthisturkeyhavefactorXII?Ofcourse,hedoesBut,hisfeatheredcompaniondoesnotDoesthisturkeyhavefactorX26CoagulationSystems-cont.ClotstabilizationFibrinstabilizingfactor(factorXIII)formsfibrinstrandcross-links.Synthesizedbymonocytesandhepatocytes.Zymogenisactivatedbythrombin(pluscalcium).AverysmallamountoffactorXIII(2-10%)isadequateforhemostasis.Convertssolublefibrinmonomers(unstable)toafibrinpolymer(stable).Lead,silver,zincandsnakevenomsareknowninhibitors.CoagulationSystems-cont.Clo27CoagulationInhibitorsTheactivityofcoagulationsystemmustbeattenuated.Numerousinhibitorsarefoundinblood.Coagulationiscontrolledbythreetypesofactions.Inhibitionofconvertingenzymes(e.g.,ATIII,C1esteraseinhibitor,a2-macroglobulin,a2-antiplasmin,a1-antitrypsin,HC-II).Actononeormoreoftheconvertingenzymes(activatedfactors).ATIII-heparinpathway:majorsystem-80%ofthethrombininhibitoryactioninplasma.Destructionofproteincofactors(e.g.,TM-PC-PSsystem).TM-PC-PSsystemdegradescofactorsV&VIII:C,inhibitingprothrombinaseandtenasecomplexes,respectively.Blockingreceptoravailabilityneededforcomplexformation(e.g.,Tissuefactorpathwayinhibitor(TFPI)andannexinV).CoagulationInhibitorsTheacti28ProposedMechanismofATIII-HeparinSystemHeparinThrombinAntithrombinIIILysinesitesSerinesiteArgininesiteHThHATIIIATIIIThProposedMechanismofATIII-H29ProposedMechanismofThrombomodulin,ProteinCandProteinS(TM-PC-PS)SystemThrombinProthrombinProteinCThrombomodulinThrombinF-XaActivatedplateletPSF-VaxCa++Ca++ActivatedProteinCProposedMechanismofThrombom30ProposedMechanismofTissueFactorPathwayInhibitor(TFPI)ActivityF-XaEndotheliumTissuefactorF-VIIaTFPIF-XaTFPITFPIF-XaProposedMechanismofTissueF31AnticoagulantFactorsAnticoagulantFactors32FibrinolyticSystemMethodforremovingclotsandmaintenanceofapatentvascularsystemandfibrindepositedduringinflammationandtissueinjurymustberemoved.Plasmin(serineprotease)primarilyresponsibleforfibrinolysis.Producedintheliverandkidney,itcirculatesinaninactiveform(plasminogen).Activators:tissueplasminogenactivator(tPA),cytokinases-urokinases(urine,CSF,tears,saliva,milk,bile,synovial,prostaticandamnioticfluids),erythrocyteerythrokinase,neutropilactivatorandfactorXII-dependentactivator(XII-prekallikrien-hagemanfactorcofactorcomplex).Inadditiontofibrinandfibrinogen,plasminwillhydrolyseavarietyofproteins.Whileplasminogenisnormallyfoundinbloodandbodyfluids,plasminisusuallyabsentduetonumerousantiplasmins.Inactivators:antithrombinIII,a2-macroglobulin,a1-antitrypsinandC1inactivator.FibrinolyticSystemMethodfor33FibrinolyticSystemandFactorsRegulatingFibrinolysis(Fibrinogenolysis)PlasminogenActivationInhibitionDamagedendotheliumKallikreinPlasminogenactivatorinhibitore-aminocaproicacidPrekallikreinStreptokinaseUrokinaseFHIIatPAPlasmina2-Antiplasmina2-MacroglobulinComplementactivationFibrin/fibrinogenDegradationproductsBiodegradationofFV,FVIII,FIX,FXIfibrinogenFirbrinogen/fibrinFibrinolyticSystemandFactor34DegradationofFibrin/FibrinogenFibrinogenorFibrinFragmentXSmallPeptidesFragmentYFragmentDSmallPeptidesFragmentEFragmentDSmallPeptidesPlasminPlasminPlasminDegradationofFibrin/Fibrinog35EvaluationofHemostasisFundamentalphysiologyandpathophysiologyofhemostasisissimilarinmammalianspecies.VariablesidenticalforlaboratoryanimalsandhumanpatientsPlateletsPlateletcount-detectionofthrombocytopeniaClotretraction-non-anticoagulatedbloodFailuretoseparate-plateletfunctiondefectorthrombocytopeniaBleedingtime(BT)-invivotest;simple;lowsensitivityUsedtoevaluateplateletfunctiondefectsThrombocytopenia-prolongsBTClottingfactordeficiencydoesnotalterBTVasculardisease(eg.,scurvy)canprolongBT(humans,guineapigs)EvaluationofHemostasisFundam36ConsiderationsforBloodCollectionClean/smoothsurfacesWanttoavoidplateletclumpingoractivationoffactorXII

UseplasticorsiliconizedglassforsamplecollectionAnimalbloodclotsfasterthanhumanblood-primeneedlewithanticoagulantCollectsamplefromanendothelial-linedvesselandcarefulvenipunctureWantavoidcontaminationwithtissuejuice(factorIII)SmallclotactivatescoagulationsysteminvalidatingresultsSamplesfromindwellingcathetersareusuallyunacceptableConsiderationsforBloodColle37SampleHandling/AnticoagulantsPlasmasamplesseparatedfromcellswithin30minutesPerformanalysesimmediatelyPlasmasamplesmaybequicklyfrozen(dryice/alcoholorliquidnitrogen)andstoredat-70oforanalysisatalaterdateActivityoffactorsVandVIIIislostrapidlyinsamplesheldatroomtemperatureCitrate(trisodiumsalt)istheanticoagulantofchoice.Oxalateanticoagulantsareacceptable-notcommonlyusedHeparin-unacceptableEDTA-unacceptable(exceptforindirectevaluationoffibrinogenconcentrationbyheatprecipitationandrefractometry)SampleHandling/Anticoagulants38Evaluation-cont.ActivatedCoagulationTime(ACT)-invivotestMeasures(seconds)timetoclotformationinfreshwholebloodCarefulattentiontosamplecollection/handlingPlateletcounts<10,000causeslightincreaseinACTResultsfromlackofplateletphospholipidfortestIncreasedACTsuggestsfactordeficiencyinintrinsicorcommonpathwaysDeficiencymustbe5%ofnormaltoprolongACTActivatedPartialThromboplastinTime(APTT)Measures(seconds)timetoclotformationincitratedplasmaIncreasedAPTT-factordeficiencyinintrinsicorcommonpathwaysDeficiencymustbe30%ofnormaltoprolongAPTTFibrinogen<50mg/dLwillprolongAPTT;inflammationmayshortenAPTTSensitivityincreasedwithsaline-dilutedplasmaHeparintherapyprolongsAPTT-differentiateusinga1:1dilutionwithnormalplasmaEvaluation-cont.ActivatedCoa39Evaluation-cont.One-StageProthrombinTime(OSPT,PT)Measures(seconds)timetoclotformationincitratedplasmaRabbitorsynthetictissuethromboplastinpreferred;humanoriginreagentgiveslongerPTtimesIncreasedPT-factordeficiencyinfactorVIIorcommonpathwayDeficiencymustbe30%ofnormaltoprolongPTFibrinogen<50mg/dLwillprolongPTSensitivityincreasedwithsaline-dilutedplasmaRussel’sViperVenomTime(RVVT)Measures(seconds)timetoclotformationincitratedplasmaIncreasedRVVT-inorcommonpathwaybutinsensitivetofactorVIIdeficiencyDeficiencymustbe30%ofnormaltoprolongRVVTFibrinogen<50mg/dLwillprolongRVVTSensitivityincreasedwithsaline-dilutedplasmaEvaluation-cont.One-StagePro40Evaluation-cont.ThrombinClottingTime(TCT)Measures(seconds)timetoclotformationincitratedplasmaIncreasedTCT-decreasedfibrinogenconcentration(<100mg/dL),dysfibrinogenemia,increasedFDPconcentration,heparintherapyFibrinogenConcentration(factorI)Inmostspecies,fibrinogenis100-400mg/dLFibrinogendecreasesinDIC,severeliverinsufficiencyandhereditaryhypofibrinogenemiaInflammationcanincreasefibrinogenconcentrationEvaluation-cont.ThrombinClot41Evaluation-cont.Fibrin-FibrinogenDegradationProducts(FDP)Measures,bylatexagglutination,theconcentrationofproductsoffibrinolysis;D-dimerassayisanothermethodformeasuringFDPIncreasedFDP-occurswithdisseminatedintravascularcoagulationorsevereinternalbleedingInmostspecies,normalFDPis<10micrograms/mLEvaluation-cont.Fibrin-Fibrin42ExampleAcuteoralstudyindogsAnimalsgiven3XLD50infoodBrodifacoumBromadioloneDiphacinoneCoagulationstudiesACTRVVTPTExampleAcuteoralstudyindog43批发和零售贸易零售业课件44批发和零售贸易零售业课件45批发和零售贸易零售业课件46批发和零售贸易零售业课件47批发和零售贸易零售业课件48Hemostasis/CoagulationGregoryS.Travlos,DVM,DACVPNationalInstituteofEnvironmentalHealthSciencesResearchTrianglePark,NC27709919-541-0653Travlos@Hemostasis/CoagulationGregoryHemostasisTheprocessbywhichbleedingisarrested.ItisaseriesofphysiologicalandbiochemicaleventswhichterminateintheformationofaninsolublefibrinclotHemostaticSequence:InteractionbetweenvesselwallandplateletsBloodcoagulationFibrinolysisHemostasisTheprocessbywhich50HemostaticComponentInteractionsThompson&Harker,1983HemostaticComponentInteracti51BloodVesselsIntactendotheliumformsathromboresistantsurface

Requiredforthefreeflowofblood;doesnotpromoteplateletadherenceoractivatecoagulationPassivemechanisms:Endothelialglycocalyx(negativecharge-repelslike-chargedparticles,e.g.,platelets).Presenceofa2-macroglobulinatcellsurface(proteaseinhibitor).Activemechanisms:Endothelialcellsremoveplateletaggregationpromotersfromcirculation(e.g.,PGF1,bradykinin,serotonin,adeninenucleotides).SecretionofPGI2-potentinhibitorofplateletaggregation,inducesvasodilation.Proteoglycanmatrixofthevesselwallinfluencesthrombogenicity.Heparin,heparansulfateanddermatansulfatehaveanticoagulantactivity;otherglycosaminoglycansandhyaluronicaciddonot.Veinshavethehighestconcentration.BloodVesselsIntactendotheliu52EndotheliumBesidestheirroleinthromboresistance,endothelialcellshaveadditionalsyntheticfunctions.ProduceVonWillebrand’sfactorAbsorbedbyplatelets;neededforadherencetocollagenProduceplasminogenactivator(tPA)MediatesfibinolysisInjuredcellsreleasethromboplastin(factorIII)Activatesthe“extrinsic”coagulationcascadeOthers(e.g.,typeIIIandIVcollagens,elastin,fibronectin,etc.)EndotheliumBesidestheirrole53BloodVesselStructureThompson&Harker,1983BloodVesselStructureThompson54PlateletsAdheretoexposedcollagen(plateletplug)Occursinseconds;cancontrolhemorrhageofminuteinjuriesSecretoryfunctions;mediatorsofcoagulationandfibrinolysisReleasesADP;stickyandpromotesplateletadherenceADPactivatesphospholipaseA2whichstimulatesthromboxaneA2synthesisReleaseofmembranefibrinogen,factorV,factorVIIIandcalciumReleaseofmembraneplateletphospholipid.PlateletsAdheretoexposedcol55Platelet-TEMmitochodrionmicrotublulesOCSgranulesPlatelet-TEMmitochodrionmicr56UltrastructuralandFunctionalPlateletAnatomyUltrastructuralandFunctional57Platelets-cont.Theroleofplateletsinhemostasisisasimportantasthecoagulationmechanism.Thrombocytopenia,thrombastheniaorthromobopathia-impairhemostasisThrombocytosisorthrombocythemia-mayimpair,butusuallypromotesclotting(predisposestothrombosis).Plateletspromotehemostasisby:ReleaseofADPandotheragonists;promotesadherence.ADPactivatesphospholipaseA2whichstimulatesthromboxaneA2synthesisThromboxaneA2-stimulatesvasoconstrictionandplateletaggregationReleaseofmembranefibrinogen,factorV,factorVIIIandcalciumComponentsofcoagulationlocalizedatsiteofinjuryReleaseofmembraneplateletphospholipid.Acceleratesthe“intrinsic”and“common”pathwaysofcoagulationPlatelets-cont.Theroleofp58ProstaglandinMetabolismHarlan&Harker,1981ProstaglandinMetabolismHarlan59HemostaticPlateletFunctionsThompson&Harker,1983HemostaticPlateletFunctionsT60PlateletResponseWhenavesselisinjuredorseveredabrief,local,reflexvasoconstrictionoccurs.

Reducesbloodflowatsite.Maintainedbyvasoactivecompounds(platelets,surroundingtissues).

Passingplateletsadheretoexposedcollagen.Occursinseconds;initiallyadhereinasinglelayerandbecomeactivated.Severeinjury-collagenservesasapotentplateletactivator.Lesssevereinjury-vWFandfibrinogenbecomethemajoractivators.Theadheredplateletsundergoaconformationalchange.Fromdiscoidtodevelopmentoflongfilopodia.ActivationofGPreceptorsforfibrinogenand/orvWF(GPIIb/IIIaandGPIb/IX/V).PlateletResponseWhenavessel61StructureoftheGPIb-IX-VreceptorTablin,2000StructureoftheGPIb-IX-Vrec62PlateletResponsetoAgonistsPlatelets-unstimulatedAdditionofADP(mildstimulation)Additionofthrombin(strongstimulation)CharacteristicdiscoidshapeShapechange(elongationandcrescents)andfilaformprocessformation(arrows)Increasedspreading,filaformprocessextension(arrows)andaggregateformation(stars)SEMplates;Gentry,2000PlateletResponsetoAgonistsP63PlateletResponsecont.Activatedplateletsreleasetheira-granuleanddensebodycontentsinducingadditionalplateletrecruitment.

Densegranules-ADP,serotoninandepinephrine.alpha-granules-fibrinogen(andvWFinhumanandpig).SynthesisandreleaseofPAFandTxA2.Theagonistsacceleratethedevelopmentofanirreversibleplateletaggregate(plateletplug).Reversiblev.irreversibleresponses.ThrombocytesofbirdsandreptilesdonotrespondtoADP.Serotoninandepinephrine:Serotonin-shapechange(rat,g.piganddog);aggregation(human,rabbit,cow,horse,pig,sheepandcat).Epinephrine-onlyhuman,primate,catandhorseplateletsappearresponsive.Eitherserotoninorepinephrinecombinedwithanotheragonist-strongresponseinallspecies.PlateletResponsecont.Activat64PlateletResponsecont.Moreaboutagonists.

PlateletActivatingFactor(PAF).Cow,horse,sheep,primate,dog,g.pigandrabbitrespondtoPAF.Humanlesssensitiveandratandmouseareinsensitivetothisagonist.ThromboxaneA2(TxA2).Strongagonist-human,

g.pigandrabbit.Weakagonist-horse.Insensitive-rat,cow,pig.Inreallife,however,plateletsareexposedtomultipleagonistsfromplateletsandothercells(e.g.,redcells,ADP;whitecells,PAF).PlateletResponsecont.Moreab65PlateletAggregationtoThrombinHarlan&Harker,1981PlateletAggregationtoThromb66HemostaticPlugFormationBaumgartner&Muggli,1980HemostaticPlugFormationBaumg67CoagulationSystemConsistsofacascadingsystemofproteinsPrimarilyoriginatingfromliver(exceptfactorIII)Circulateininactiveform(except,possibly,factorVII)Systemincludes:EnzymaticfactorsNon-enzymaticfactorsTissuethromboplastin(factorIII)Calcium(factorIV)Plateletphospholipid(PF3)-structuralcomponent;acceleratesfactoractivationAnticoagulantfactorsThecoagulationsystemconsistsofthreepathways(intrinsic,extrinsicandcommon)CoagulationSystemConsistsof68批发和零售贸易零售业课件69ProcoagulantFactorsProcoagulantFactors70CoagulationSystems-cont.EnzymaticfactorsCirculateasnon-activezymogens-mustbeactivatedtofunctionActivatedenzymaticfactorsarenotconsumedduringclotting(exceptfactorsIIandXIII)PartialdeficiencyresultsinpartiallossofclottingabilityActivatedenzymaticfactorsinhibitedbyantithrombinIII(complexedwithheparin)andsomealpha-2-glycoproteinsEnzymaticfactors:XIandXII(contactfactors)II,VII,IXandX(vitaminK-dependentfactors)XIII(clotstabilizingfactororfibrin-stabilizingfactor)CoagulationSystems-cont.Enz71CoagulationSystems-cont.Non-enzymaticfactorsOriginatefromliverbutassociatewithplateletmembranes(alsofoundinplasma)Normalclottingwithpartialdeficiency;almosttotalabsenceneededtoaffecthemostasisorclottingClottingconsumesthesefactors-absentinserumNoknownnaturalinhibitorsConsideredreactiveproteins-increasedduringinflammatoryandneoplasticprocesses(exceptfactorIII)Non-enzymaticfactors:Fibrinogen(factorI)FactorVFactorVIII:C(associatedwithVonWillebrand’sfactor)CoagulationSystems-cont.Non72CoagulationCascadeInteractionsCoagulationCascadeInteractio73DoesthisturkeyhavefactorXII?Ofcourse,hedoesBut,hisfeatheredcompaniondoesnotDoesthisturkeyhavefactorX74CoagulationSystems-cont.ClotstabilizationFibrinstabilizingfactor(factorXIII)formsfibrinstrandcross-links.Synthesizedbymonocytesandhepatocytes.Zymogenisactivatedbythrombin(pluscalcium).AverysmallamountoffactorXIII(2-10%)isadequateforhemostasis.Convertssolublefibrinmonomers(unstable)toafibrinpolymer(stable).Lead,silver,zincandsnakevenomsareknowninhibitors.CoagulationSystems-cont.Clo75CoagulationInhibitorsTheactivityofcoagulationsystemmustbeattenuated.Numerousinhibitorsarefoundinblood.Coagulationiscontrolledbythreetypesofactions.Inhibitionofconvertingenzymes(e.g.,ATIII,C1esteraseinhibitor,a2-macroglobulin,a2-antiplasmin,a1-antitrypsin,HC-II).Actononeormoreoftheconvertingenzymes(activatedfactors).ATIII-heparinpathway:majorsystem-80%ofthethrombininhibitoryactioninplasma.Destructionofproteincofactors(e.g.,TM-PC-PSsystem).TM-PC-PSsystemdegradescofactorsV&VIII:C,inhibitingprothrombinaseandtenasecomplexes,respectively.Blockingreceptoravailabilityneededforcomplexformation(e.g.,Tissuefactorpathwayinhibitor(TFPI)andannexinV).CoagulationInhibitorsTheacti76ProposedMechanismofATIII-HeparinSystemHeparinThrombinAntithrombinIIILysinesitesSerinesiteArgininesiteHThHATIIIATIIIThProposedMechanismofATIII-H77ProposedMechanismofThrombomodulin,ProteinCandProteinS(TM-PC-PS)SystemThrombinProthrombinProteinCThrombomodulinThrombinF-XaActivatedplateletPSF-VaxCa++Ca++ActivatedProteinCProposedMechanismofThrombom78ProposedMechanismofTissueFactorPathwayInhibitor(TFPI)ActivityF-XaEndotheliumTissuefactorF-VIIaTFPIF-XaTFPITFPIF-XaProposedMechanismofTissueF79AnticoagulantFactorsAnticoagulantFactors80FibrinolyticSystemMethodforremovingclotsandmaintenanceofapatentvascularsystemandfibrindepositedduringinflammationandtissueinjurymustberemoved.Plasmin(serineprotease)primarilyresponsibleforfibrinolysis.Producedintheliverandkidney,itcirculatesinaninactiveform(plasminogen).Activators:tissueplasminogenactivator(tPA),cytokinases-urokinases(urine,CSF,tears,saliva,milk,bile,synovial,prostaticandamnioticfluids),erythrocyteerythrokinase,neutropilactivatorandfactorXII-dependentactivator(XII-prekallikrien-hagemanfactorcofactorcomplex).Inadditiontofibrinandfibrinogen,plasminwillhydrolyseavarietyofproteins.Whileplasminogenisnormallyfoundinbloodandbodyfluids,plasminisusuallyabsentduetonumerousantiplasmins.Inactivators:antithrombinIII,a2-macroglobulin,a1-antitrypsinandC1inactivator.FibrinolyticSystemMethodfor81FibrinolyticSystemandFactorsRegulatingFibrino