缺血性腦損傷及腦保護

IschemicBrainInjuryandProtection1,

What:

ischemicbraininjury2,

Why:mechanismsunderlying3,

Self-protection:repair/protectitselfafterstroke4,

Therapies:

translationalstrategiesOUTLINE1,Whatisischemicbraininjury?Adecreaseinthebloodsupplytoabodilyorgan,tissue,orpartcausedbyconstrictionorobstructionofthebloodvessels.ISCHEMIA

:

(NewLatinischaemia,fromGreekiskhaimos,astoppingoftheblood:iskhein,tokeepback;seesegh-inIndo-Europeanroots+haima,blood)/ischemiaMayalsobespelledas:ischaemiaorisch?mia

RelatedTermsIschemia

缺血

shortageofthebloodsupply(oxygen,glucose,etc)Hypoxia

缺氧

shortageofoxygenAnoxia

缺氧

anextremeformofhypoxia,absenceofoxygenBrainischemia

腦缺血

insufficientbloodflowtothebrain(eg:ischemicstroke)Ischemiccascade

缺血級聯反應

aseriesofbiochemicalreactionsthattakeplaceaftersecondstominutesofischemia.Stroketypesandincidence中風中絕大多數是缺血性中風腦血栓形成腦栓塞Blockageofabloodvessel(inthebrainorneck)CerebralischemiaIschemicBrainInjuryFewseconds:littleornodamage10seconds:nooxygensupply30seconds:changesinbrainmetabolism1minute:noneuronalfunctionalactivities6-8minutes

→neuronaldeath,InfarctionNeurologicaldysfunctionoccurswithinsecondstominutesofvesselocclusionIschemicinjuryandcelldeathcontinuesinstagesforminutes,hours,andevendaysofvesselocclusion血栓使大腦中動脈栓塞，供血區血供不足大腦中動脈缺血腦水腫RedNeuronsMacrophagesOedemaCystformation神經細胞受損缺血1h再灌24h，同側和對側皮層、紋狀 體神經元變化（CV染色）cortexstriatumcontralateralipsilateralSeverelydamagedtissueLowperfusiontissueAfterhourstodays,ischemiccoreterritoryexpands.Ischemiccoreappearswithinminutestohours.腦缺血造成腦梗死缺血核心區ischemiccore缺血半影區penumbraIschemiccore:

irreversiblydamagedtissuesdistaltoanoccludedbloodvessels

<20%ofbaselinebloodflowlevelsdepletedATPstoresirreversiblefailureofenergymetabolismSalvageabletissueisthetargetfortherapy.Ischemicpenumbra:

significantlydepressedtissueperfusionbarelysufficienttosupportbasalATPlevelsaswellasnormalionicgradientsinthepresenceofelectricalsilenceandsuppressedproteinsynthesis

“atrisk”region:functionallyimpaired,potentiallysalvageableDamageMechanismsProtectiveMechanismsCellFateischemiaINischemicpenumbra：1，啟動細胞死亡機制2，激活腦內自身保護機制Live?Dead?2,Whydoesischemiacause

braininjury?

Experimentalmodels

ProminentmechanismsunderlyingneuronalinjuryRat,mice,andgerbilarethecommonlyusedmodelanimals.Monkey,cat,andrabbitarealsousedtoestablishstrokemodels.外周血液經兩對動脈進入腦內：頸動脈和椎動脈阻斷血流（顱內、顱外）：腦缺血

Middlecerebralarteryocclusion(MCAO)

Photothrombosis

光化學誘導

Spontaneousbraininfarction

Four-vesselocclusion

四血管結扎

Commoncarotidarteryocclusioningerbils

Two-vesselocclusionplushypotention

兩血管結扎并低血壓

Cardiacarrestcerebralischemia(CACI)心臟驟停

Hypoxicischemia

低氧缺血

Intracranialhypertensionandcommoncarotidarteryocclusion

Focalbrainischemia(transient/permanent)

GlobalbrainischemiaLonga,E.Z.,P.R.Weinstein,S.Carlson,R.Cummins(1989)."Reversiblemiddlecerebralarteryocclusionwithoutcraniectomyinrats".Stroke20(1):84–91.PMID2643202IntraluminalsutureMCAO大腦中動脈栓塞MCAO-inducedstrokemodelinrhesusmonkey大鼠行為學視頻MCAOinducesbrainedema(bottomleft)andinfarction(right).TopleftshowsMCAO-affectedregioninhumanbrain.rosebengal玫瑰紅B四碘四氯熒光素二鈉PhotothrombosisstrokemodelWatsonBD,DietrichWD,BustoR,WachtelMS,GinsbergMD.(1985).Inductionofreproduciblebraininfarctionbyphotochemicallyinitiatedthrombosis.AnnNeurol.17(5):497-504Photosensitivedye:rosebengalSpecificlighting:鹵素燈或氙燈Photochemicalreactionproducts:

reactiveoxygenspeciesDamage:VascularendothelialcellinjuryThrombosisformationLeft:Cortical“spot”lesion,carbonblackviewat4hRight:Occludedarterioleinpia,perfusedat2min;SEMx4160Left:562nmdyelaserbeam

positionedondMCARight:Rosebengaldye-photosensitized

dMCAthrombusImagesfrom/x301.xml光化學誘導模型可用于研究溶栓藥物的作用Imagesfrom/lawrence.lab/files/page_4_01.html全腦缺血模型中，海馬神經元最易受影響HypoxiachamberImagesfromJournalofCerebralBloodFlow&Metabolism(2004)24,259–270ligationoftheright(orleft)commoncarotidarteryof7-day-oldpups,followedby90minuteofhypoxia(8%02and92%N2)at37℃.

Hypoxia-ischemiamodel

CellcultureOrganotypicbrainslicecultureIn

VitrocultureOxygen-glucosedeprivation(OGD)

hypoxiachemicalhypoxia

NeuronalcultureOrganotypicslice——maintainneuronalorganizationforextendedperiodsoftime

更接近在體狀態數周至數月(A)Brightfield,(B)and(C)PI-fluorescenceimagesofratorganotypichippocampalslicecultures(labeledareCA1,CA3subfieldsandDG:dentategyrus).(B)Neuronalcelldeath24hafter‘test’ischemia(40minofOGD).(C)Reducedcelldeathinapreconditionedslice(15minofOGD48hpriortotestischemia).Barindicates0.2mm.Neuroscienceletters,384(2005):87-92ischemiatreatment2,Whydoesischemiacause

braininjury?

Experimentalmodels

Prominentmechanismsunderlyingneuronalinjury缺血細胞內信號轉導細胞間通訊缺血中心區細胞死亡缺血損傷向四周擴布？AB1B2CD神經元的突觸結構CBFreduction↓Energyfailure↓Anoxicdepolarization,Excitotoxicity,Oxidativestress,Necrosis↓Peri-infarctdepolarization,Calciumoverload,Mitochondrialdamage↓Inflammation,celldeathNeuronalischemicinjurycascade

Glutamateexcitotoxicity谷氨酸興奮毒神經元受損的早期環節(1)LucasD.R.OlneyJ.SchwarczR....Pre-1984Post-19841984LUCASDR,NEWHOUSEJP.(1957).ThetoxiceffectofsodiumL-glutamateontheinnerlayersoftheretina.AMAArchOphthalmol.58(2):193-201OlneyJW.(1969).Brainlesions,obesity,andotherdisturbancesinmicetreatedwithmonosodiumglutamate.Science.164(880):719-21

過量谷氨酸可以破壞新生小鼠視網膜神經元(LucasDR,1957)全身應用谷氨酸可導致腦內神經元的退化性病變(OlneyJW,1969)谷氨酸引起神經元死亡的作用通過興奮突觸后膜上離子通道型谷氨酸受體1984

缺血時細胞外谷氨酸含量上升(Benvenisteetal.).

谷氨酸受體拮抗劑保護培養的神經元免受谷氨酸或者門冬氨酸興奮毒(Rothman).

NMDA受體拮抗劑降低缺血誘導的神經元損傷

(Simonetal.).

Post-19841984Pre-1984腦缺血后細胞間隙谷氨酸含量顯著升高corepenumbraGLUCytosol10mMVesicles100mMExtracellular1MTGLUGLUSynapticspace1mM？谷氨酸濃度梯度谷氨酸轉運體的作用胞外<<胞漿<<囊泡內遞質釋放時excitotoxicityEndogenousPresynapticPostsynapticGliaGlu-RGluvGlucGlucs.c.e.s.e.s.Glia1984Pre-1984Post-1984YProcessesinvolvedintheinactivationofsynaptictransmissionYYYYYYUU=uptakeDD=diffusionYZMM=metaboliteYYYYRR=receptordesensitisationFaliureofglutamatereuptakeOutInATPNa+K+

K+Na+

K+CGlu2Na+DeficientglutamateuptakeDeficientenergysupply(ischaemia,mitochondrialdamage)LossoftheNa/K-transmembranegradient(drivingforceofthecarrier)谷氨酸轉運體AMPA-RPostsynapticabnormalitiesleadingtoexcessiveexcitationIonotropicreceptors(GluR)Metabotropicreceptors(mGluR)Ca2+NMDA-RNa+Na+Kainate-RG

Increasedaffinityoftheglutamatebindingsite;

Increaseddensityofglutamatereceptor;

Deficientcationselectivityoftheionophore;

Abnormal(positive)modulationofGluRfunction.谷氨酸受體Presynaptic

release:↑Reuptake:↓synapticglutamate:↑Postsynaptic

receptor:↑Excitation:↑Na+內流Na+內流Ca2+內流內鈣釋放Ca2+內流NMDA受體AMPA受體KA受體mGlu受體谷氨酸水腫內鈣超載nNOSPLA2…ROSCelldeath？ClinicaltrialsfailureCategoryNameClinicalefficacyGlutamatereceptorblockadeAptiganel/dextrophan/EliprodilNoneGlutamatehypothesismay:Oversimplifiedthecomplexityofthecelldeathprocesses:Underestimatedthediversityofexpressingcelltypes:

beyondneurons

Shouldconsidertheheterogeneityofglutamateresponses:

selectivelytargetFunctionaldiversityofNMDARsisrootedintheirlocationandsubunitdiversity.Example1:→Selectivedrugtargetisimportant.Location:synapticvs.extrasynapticSubunitcomposition:GluN1,GluN2(2A-2D),GluN3(3A-3B)

GluN1/GluN2A:dominatinginadulthood;

withinsynapse

greaterassociationwithcellsurvival

GluN1/GluN2B:dominatingearlyindevelopment;

outsidesynapse

linkedtocelldeathsignalingGluN3:inhibitorysubunit,peakattheendofthefirstpostnatalweeksuppressesNMDARactivityLocationAssociateswithDifferentIntracellularSignalsParsonsMP,etal.Neuron,2014GluN2BLaiTW,etal.ProgNeurobiol.,2014SubunitscompositionAssociateswithDifferentIntracellularSignalsGluN2AC-terminaldomainSynapticactivityviaGluN2A:CREB/BDNFpositivefeedbackloopExtrasynapticactivityviaGluN2B:CREBshut-offpathwayPhospholipidpathwaysleadingtoneuronaldeathandsurvival:AktandPTENPI3KPIP3PIP2PTENAktAmJPhysiolCellPhysiol308:C570-C577,2015ImmunocytochemistryshowedcolocalizedlabelingofGluN1Igreen)andGluN3A(red)inprimarycorticalneurons.ExpressionpatternsofGluN3Ainthemousebrain.NeuroprotectiveeffectofGluN3AagainstexcitotoxicinsultsincorticalNeurons.NeuroprotectiveroleofGluN3AinischemicstrokeoftheadultmouseGLIAL:GLAST/EAAT1RetinalMullercells77MCerebellarBergmanngliaGLT-1/EAAT2Astrocytesthroughoutbrain2MNEURONAL:EAAC1/EAAT3Neuronalsomataanddendrites15MEAAT4CerebellarPurkinjecells3.3MEAAT5Retinalphotoreceptorsand64M

bipolarcellsThenameoftheglutamatetransporterfamilymembers.Theexcitatoryaminoacidtransporter(EAAT)namesareforthehumantransporters;othernamesweregivenwhenthetransporterswerefirstclonedinnonhumanspecies.Example2:NonneuronalcelltypesCerebralcortexStriatumHippocampusThalamusInsituhybridizationforEAAT1mRNAandimmunohistochemistryforEAAT1proteinafterH-IDoublestainingwithconfocallaserscanningmicroscopicanalysisinneonatalratbrainsImmunohistochemicalstainingintheneonatalratbrainat48hfollowingH-IH-I+sense

H-I+antisense0510152025cerebralcortexstriatumhippocampusthalamusEAAT1-positivecells/mm2vehicleantisensesensemissense****Sham-operationH-I+senseH-I+antisenseCresylvioletstainingintheneonatalratbrainat48hfollowingH-I:*Example3:PDZproteinsatamammalianexcitatorysynapseintracellularcalciumoverload胞內鈣超載神經元受損的早期環節(2)extracellularcalcium:[Ca2+]o=1~10mMintracellularcalcium:

cytosolic：

0.1%ofintracellularcalcium[Ca2+]i=100nM=0.1M

calciumstores：99.9%calciumbindingprotein:calmodulin,calbindin,parvalbumin,calretinin

endoplasmicreticulummitochondriaCalciumhomeostasisinneuronsVOCs:voltage-operatedchannelsROCs:receptor-operatedchannelsSMOCs:second-messengeroperatedchannelsSOCs:store-operatedchannelsRyRs:ryanodinereceptors,bycalciumitself(CICR)orbyvoltage(DICR)SR:sarcoplasmicreticulumER:endoplasmicreticulumS:ahypotheticalcalciumsensorAllcurrentlyknowncalciumchannelproteinsCalciuminflux:glutamate-dependentglutamate-independentCalciumreleasefromstores:CalciumeffluxERmitochondria3Na+2Ca2+Na+/Ca2+exchangerCa2+ATP-dependentCa2+pumpsIP3receptoruniporterCa2+pumpsNMDARmGluRsvoltage-dependentCa2+channels(VDCC)IP3GqPLCAMPARNa+/Ca2+exchangerNicholsonC,BruggencateGT,SteinbergR,St?ckleH.(1977).Calciummodulationinbrainextracellularmicroenvironmentdemonstratedwithion-selectivemicropipette.ProcNatlAcadSciUSA.74(3):1287-90.

anoxiatriggersrapidtranslocationofcalciumfromextratointracellularspacesinneuraltissue.Thisworkpromptedspeculationaboutwhycertainneuronsareselectivelymoresensitivetoischemia,namelybecauseofahigherdensityofcalciumchannelsintheirplasmamembranes.1977;Nicholsonetal:缺血缺氧導致胞內鈣超載Glutamate-inducedCa2+transientsincorticalneuronsobservedbyconfocallasermicroscopy.Thetimecourseofthenormalizedfluorescenceintensity.Zerotimeindicatesbeginningofpostexposurephase.Eachcurverepresentsapointrecordingfromadifferentcellinthedish.Fluo-3flunorescenceintensitywereobtainedbeforeandduringstimulationwith1mMglutamateatintervalsof4sec.IntracellularcalciumoverloadingnormalaspartatewashAsp+tauERmitochondria3Na+2Ca2+Na+-Ca2+exchangerCa2+ATP-dependentCa2+pumpsIP3receptoruniporterCa2+pumpsNMDARmGluRsvoltage-dependentCa2+channels(VDCC)IP3GqPLCAMPARIschemia!!細胞內游離鈣離子激活一系列鈣離子依賴性酶反應Ca2+→calcineurin-mediateddephosphorylationandactivationofDAPK1atser-308Excitotoxicityrecruitsdeath-associatedproteinkinase1(DAPK1)tothecytoplasmictailofGluN2B.Ca2+→calpainactivation→mGluR1truncation→neuronaldeath→p35truncation→neuronaldeath→STEP61truncation→neuronaldeathCouplingbetweenNMDAReceptorandAcid-SensingIonChannelContributestoIschemicNeuronalDeathASIC1a:

Acid-sensingionchannels(ASICs)highlypermeabletoCalciumCalciuminfluxGlobalIschemiaRapidlyElevatedSerinePhosphorylationofASIC1aSubunitGlobalIschemiaIncreasedtheAssociationofCaMKIIawithASIC1aNMDARActivationIsRequiredforIschemia-InducedEnhancementofASIC1aPhosphorylationNR2B-specificblockersNMDARAMPARActivationofNR2B-NMDARsEnhancedASICCurrentsNR2BAntagonistorCaMKIIInhibitorPreventedOGD-InducedEnhancementofASICCurrentsinHippocampalNeuronsNeuroprotectionbyASIC1aGeneDeficiencyandASIC1aMutantsinCulturedHippocampalNeuronsorCOS7Cells

NMDAR-CaMKIIcascadeisfunctionallycoupledtoASICsandcontributestoacidotoxicityduringischemia.SpecificblockadeofNMDAR/CaMKII-ASICcouplingmayreduceneuronaldeathafterischemiaandotherpathologicalconditionsinvolvingexcessiveglutamatereleaseandacidosis.Thus:Oxidative/nitrosativestress氧化/硝化應激神經元受損的分子基礎AngioplastyKeshandisease(seleniumdeficiency)TraumaStrokeNeurotoxinsParkinson’sDiseaseAlzheimer’sDiseaseRadiationAgingCancerInflammatory-immuneinjuryIschemia-reperfusionDiabetesKidneySkinHeartJointsLungBrainMulti-organVesselsGIEyeRenalgraftGlomerulonephritisBurnDermatitisPsoriasisIschemicbowelEndotoxinliverInjuryAsthmaHyperoxiaVasospasmAtherosclerosisRheumatoidAthritisDegenerativeretinaldamageCataractogenesisOxidativeStressOxidativestress-relatedclinicalconditionsWhatisoxidativestress?Oxidativestressistheimbalancebetweencellularproductionofreactiveoxygenspecies(ROS)andtheabilityofcellstodefendagainstthem.氧化應激：體內氧化與抗氧化作用失衡，氧化作用增加，產生大量氧化中間產物。硝化應激：由NO或NO衍生的活性氮族與活性氧族共同聯合發生的反應，可使蛋白質的酪氨酸硝化成硝基酪氨酸，或者使半胱氨酸巰基發生S-亞硝基化。Reactiveoxygenspecies(ROS)

活性氧自由基

Freeradicals:自由基

AnychemicalspecieswithoneormoreunpairedelectronsReactivenitrogenspecies(RNS)

活性氮自由基

themostcommoncellularfreeradicals-superoxideradicalO2-（超氧陰離子）-hydroxylradical?OH（羥自由基）-nitricoxideradicalNO?Others:(notfreeradicalsbutcanleadtothegenerationoffreeradicals)-Hydrogenperoxide

H2O2-PeroxynitriteONOO-

過氧亞硝酸陰離子ROS/RNSarephysiologicallygeneratedandmaintainedatrelativelylowlevels.Enzymes,antioxidantsROS的清除DifferentsourcesofROSgenerationleadingtovariouslipidperoxidesformation.腦缺血腦缺血腦缺血產生大量自由基，抗自由基系統活性下降Duringischemia,ROSweregeneratedprincipallybymitochondria.Recentlyshown:

NADPHoxidase(NOX)istheprimarysourceofsuperoxideinducedbyNMDAreceptoractivation.PKCnNOSXDH:黃嘌呤脫氫酶XO：黃嘌呤氧化酶

involvedinpurinedegradationNOX：NADPH氧化酶

amembrane-boundenzymecomplexbefoundmainlyintheplasmamembraneNOS：NO合酶線粒體功能障礙，SOD等活性下降黃嘌呤氧化酶過度活化次黃嘌呤→黃嘌呤+尿酸+O2-花生四烯酸代謝增加

Ca2+→PLA2/PLC→AA↑→O2-NOS→

NO，進一步介導自由基的生成。。。。。。腦缺血后多條途徑產生自由基：

TheNobelPrizeinPhysiologyorMedicine1998RobertF.Furchgott

SUNYHealthScienceCenter

Brooklyn,NY,USA

b.1916LouisJ.Ignarro

UniversityofCaliforniaSchoolofMedicine

LosAngeles,CA,USAb.1941FeridMurad

UniversityofTexasMedicalSchoolatHouston

Houston,TX,USAb.1936Http:///research/medicine/biochemistry/bioc800/sig02-06.htmNOScoupling→NONOSuncoupling→O2-insteadofNOTypesofNOSnNOSneuronalNOSCentralandperipheralneuronalcellsCa2+dependent,usedforneuronalcommunicationiNOSinducibleNOSMostnucleatedcells,particularlymacrophagesIndependentofintracellularCa2+

InducibleinpresenceofinflammatorycytokineseNOSendothelialNOSVascularendothelialcellsCa2+dependentVascularregulation

H+

NO+O2

ONOO-

ONOOH

NO2?+OH?

協同花生四烯酸損Pr、核酸、脂質膜損Syn.前Glu轉運體

Glureuptake

Glu濃度腦缺血時大量超氧化物與NO反應CategoryNameClinicalefficacyFreeradicalscavengers/antioxidantsPergorgotein/tirilazad/ebselenNoneorminimalClinicaltrialsfailureTosuppressdeleteriousradicalswithoutinterferingwithendogenoussignalingwillbeimportant.FromCalabresietal.,2003Celldeath細胞死亡神經元受損的最終歸宿壞死凋亡焦亡自噬壞死性凋亡JNeurochem.(2015)10.1111/jnc.13362ApoptosisandnecrosisCellshrinkage,membraneblebbing,chromatincondensation,apoptoticbodyformationMethodsofdetectingapoptosisMorphologyElectronmicroscopyLightmicroscopyChromatincondensationStainingnucleiwithfluorescentdyessuchasDAPI,Hoechst,acridineorangeDNAfragmentationTUNEL(TdT-mediateddUTP-biotinnickendlabeling)InternucleosomalDNAladderFACSanalysisofDNAcontent(<2NDNA)Viabilitydyeexclusion,trypanblue,propidiumiodideAnnexinVbindingtophosphatidylserinewhichisflippedtooutsideofplasmamembrane earlyinapoptosisMTT-assaysabilityofactivemitochondriatocleavecolorimetricsubstrateCaspaseActivation--caspasecleavageeventsCytochromecreleasefrommitochondria

UVApoptosisinResponsetoUV-irradiationAnnexin-VstainingHoechststainingDNAFragmentationApoptosissignalsFasligandFasCaspase8BidCytochromecCaspase3Caspase7FADDIntrinsicpathwayExtrinsicpathwayAPOPTOSISBclBax細胞內源性通路細胞外通路BaxTakahashiA,MasudaA,SunM,CentonzeVE,HermanB.(2004).Oxidativestress-inducedapoptosisisassociatedwithalterationsinmitochondrialcaspaseactivityandBcl-2-dependentalterationsinmitochondrialpH(pHm).BrainResBull.62(6):497-504.LinksAutophagy:自噬Energydependentprocess“自食”

LC3dependentOrLC3independentTreatmentofstrokeCategoryNameClinicalefficacyAnticoagulation/thrombolysisAspirin/heparin/tPA/urokinaseModestGlutamatereceptorblockadeAptiganel/dextrophan/EliprodilNoneVoltage-gatedCa2+channelblockersNimodipine/lifarizine/flunarizineNoneNa+channelblockersLubeluzole/riluzolUnclearornoneVoltage-dependentK+-channelagonistBMS-204352BeingtestedEnhancementofinhibitoryneurotransmissionClormethiazoleBeingtestedFreeradicalscavengers/antioxidantsPergorgotein/tirilazad/ebselenNoneorminimalNeuralrepairCiticholine/troferminUnclearorminimalTreatmentofstrokeCategoryNameClinicalefficacyAnticoagulation/thrombolysisAspirin/heparin/tPA/urokinaseModestGlutamatereceptorblockadeAptiganel/dextrophan/EliprodilNoneVoltage-gatedCa2+channelblockersNimodipine/lifarizine/flunarizineNoneNa+channelblockersLubeluzole/riluzolUnclearornoneVoltage-dependentK+-channelagonistBMS-204352BeingtestedEnhancementofinhibitoryneurotransmissionClormethiazoleBeingtestedFreeradicalscavengers/antioxidantsPergorgotein/tirilazad/ebselenNoneorminimalNeuralrepairCiticholine/troferminUnclearorminimal動物實驗有效，但臨床療效不佳！Everythingworksinanimalsbutnothingworksinpeople.O’collinsetal,2006DamageMechanismsProtectiveMechanismsCellFateischemia缺血半影區的神經元病理變化：1，啟動細胞死亡機制2，激活腦內自身保護機制Live?Dead?3,Howdoesthebrainrepair/protectitselfafterstroke?

Neurogenesisaftercerebralischemia!

SVZ:subventricularzoneSGZ:subgranularzoneNeurogenesisinthestriatuma,NeuralstemcellsorprogenitorcellsresideintheSVZ.b,Focalischemicinsultsgiverisetoincreasedproliferationofprogenitors.c,Neuroblastsformedafterandtosomeextentalsobeforethestrokethenmigratetothedamagedpartofthestriatum.d,Theyexpressmarkersspecificforstriatalprojectionneurons.CurrentopinioninNeurobiology,2003,13:127-132SelfrepairmechanismNaturemedicine,2002,8(9):963-970Dcx(green)andBrdu(red)immucoreactivityintheipsilateralstriatuminfusedwithsaline(upperlayer)andAra-c(lowlayer).Naturemedicine,2002,8(9):963-970Strokegeneratedcellsexpressmarkersofdevelopingstriatalneurons2weeksafterstrokeandmarkersofmaturestriatalneurons5weeksafterstroke..DARPP32BrdUDARPP32-BrdUScience,(287),2000,1433-1438NeurogenesisinthehippocampusNestininthehippocampusafterischemia.Nonischemichippocampus(A,D).Sevendaysafterischemia,(B,E)

JournalofNeuroscienceResearch69:750–756(2002)

Vascularremodelingaftercerebralischemia!StrokeinducestransientdecreaseofvesseldensityinSVZandlong-termincreaseofSVZvolumeandvesseldensityinadjacentstriatum.Strokeinduceslow-gradeangiogenesisinSVZandadjacentstriatum.Neuroblastsmigratelong-termafterstrokeclosetobloodvesselsinstriatalsubzonewithincreasedvascularization.JNeurochem.(2015)10.1111/jnc.13362Neurovascularunitdynamicsinthecerebraltissueatthesubacuteperiodpost-strokeTightjunctionsbreak;Basallaminadegrade;Astrocytesreactive;Parenchymalswells;TrophicfactorsincreaseProgressofcellularalterationinducedbystroke<8h8-48h>48hJNeurochem.(2015)10.1111/jnc.133624,NewTranslationalstrategies神經元并非孤立存在神經元星形膠質細胞神經元、星形膠質細胞小膠質細胞神經元神經元

星形膠質細胞RemodelingtheNeurovascularUnitinsteadofprotectneurononlyWhitematterstrokeinjury:disruptedconnectivity;injuredaxonsandglialcells

Differsfromthoseingreymatter!Brainresearch,2015(1623):123-134Ischemiccore:axon-gliacompletelossPeri-infarctarea:demyelinationRegenerativeresponseInhibitorysignalsTrophicfactorsMolecularpathwayinvovledinWhitematterstrokeinjuryandrepair:

Extracellularmatrixrelatedproteins:CSPGs,hyaluronan,MMPsActivity