New Alzheimers Definition Moves Researchers Closer to Early Detection and InterventionWord文档格式.docx
《New Alzheimers Definition Moves Researchers Closer to Early Detection and InterventionWord文档格式.docx》由会员分享,可在线阅读,更多相关《New Alzheimers Definition Moves Researchers Closer to Early Detection and InterventionWord文档格式.docx(20页珍藏版)》请在冰点文库上搜索。
CHICAGO,April19,2011–Forthefirsttimein27years,newcriteriaandguidelinesforthediagnosisofAlzheimer’sdiseasehavebeenpublishedbythreeexpertworkgroupsspearheadedbytheAlzheimer’sAssociationandtheNationalInstituteonAging(NIA)oftheNationalInstitutesofHealth(NIH).
Theworkgroupspublishedfourarticlesincludingready-to-useclinicaldiagnosticcriteriaforAlzheimer’sdiseasedementiaandmildcognitiveimpairment(MCI)duetoAlzheimer’s.AresearchagendawasproposedforpreclinicalAlzheimer’s.TheuseofbiomarkersinAlzheimer’sdementiaandMCIduetoAlzheimer’swasalsoproposedasaresearchagendaonly,andisnotintendedforapplicationinclinicalsettingsatthistime.
Thearticles–collectively,theNationalInstituteonAging/Alzheimer’sAssociationDiagnosticGuidelinesforAlzheimer’sDisease–expandthedefinitionofAlzheimer’stoincludetwonewphasesofthedisease:
(1)presymptomaticand
(2)mildlysymptomaticbutpre-dementia,alongwith(3)dementiacausedbyAlzheimer’s.ThisreflectscurrentthinkingthatAlzheimer’sbeginscreatingdistinctandmeasurablechangesinthebrainsofaffectedpeopleyears,perhapsdecades,beforememoryandthinkingsymptomsarenoticeable.
“Itisourhopethatincorporatingscientificknowledgegainedandtechnologicaladvancesmadeoverthepastquartercenturywillimprovecurrentdiagnosis,bringthefieldclosertoearlierdetectionandtreatment,andultimatelyleadtoeffectivedisease-modifyingtherapies,”saidWilliamThies,Ph.D.,ChiefMedicalandScientificOfficerattheAlzheimer’sAssociation.“Developmentandpublicationofthesearticlesisamajorlandmarkinthefield.Thatsaid,publicationofthesearticlesisnotyettheendoftheprocessofdevelopingnewdiagnosticcriteriaforAlzheimer’s,butisanothermajorstepintheprocess.”
“Thenewguidelinesreflecttoday’sunderstandingofhowkeychangesinthebrainleadtoAlzheimer’sdiseasepathologyandhowtheyrelatetotheclinicalsignsofmildcognitiveimpairmentandAlzheimer’sdiseasedementia,”saidCreightonPhelps,Ph.D.,ProgramDirectoroftheAlzheimer’sDiseaseCentersProgramattheNationalInstitutesofHealth.“Wearealsobeginningtobeabletodetectthesechangesatapreclinicalstage,longbeforesymptomsappearinmanypeople.Withfurtherresearchonbiomarkers,assetforthinthenewguidelines,wemayultimatelybeabletopredictwhoisatriskfordevelopmentofmildcognitiveimpairmentandAlzheimer’sdementia,andwhowouldbenefitmostasinterventionsaredeveloped.”
TheproposednewAlzheimer’sdiseasediagnosticguidelineswerepublishedonlinetodaybyAlzheimer’s&
Dementia:
TheJournaloftheAlzheimer’sAssociation.HardcopypublicationisscheduledfortheMay2011issueofthejournal.
ThreeStagesofAlzheimer’sDisease
ThecurrentdiagnosticcriteriaforAlzheimer’s*,forthemostpart,focusonreliablediagnosiswhensignsofproblemsinthinking,learning,andmemoryarenoticeabletoanindividual,family,andfriends.ButresearchtellsusthatAlzheimer’slikelybeginsyears,maybeevendecades,priortosymptomsappearing.
ThenewarticlesrefertothreephasesofAlzheimer’sdiseaseprogressionovertime:
PreclinicalAlzheimer’sDisease–Measurablechangesinbiomarkers(suchasbrainimagingandspinalfluidchemistry)thatindicatetheveryearliestsignsofdisease,beforeoutwardsymptomsarevisible.Currently,therearenoclinicaldiagnosticcriteriaforthisphase,butthegroupprovidesascientificframeworktohelpresearchersbetterdefinethisstageofAlzheimer’s.(Seesupplement5.)Mildcognitiveimpairment(MCI)duetoAlzheimer’sDisease–Mildchangesinmemoryandthinkingabilities,enoughtobenoticedandmeasured,butnotimpairmentthatcompromiseseverydayactivitiesandfunctioning.DementiaduetoAlzheimer’sDisease–Memory,thinkingandbehavioralsymptomsthatimpairaperson’sabilitytofunctionindailylife.(Formoredetails,seesupplement3.)
Accordingtotheauthors,inordertofacilitatethepossibilityoffuturepresymptomatictreatmentofAlzheimer’s,itwasimportanttodefinethediseasefromtheearliestchangesinthebrain,notonlytheobservable,symptomaticstagesofthedisease.TheauthorsproposethatAlzheimer’sbeginswithalongasymptomaticperiodduringwhichdetrimentalchangesareprogressinginthebrain,andindividualswithbiomarkerevidenceofthesechangesareatincreasedriskfordevelopingcognitiveandbehavioralimpairmentandprogressiontoAlzheimer’sdementia.
Abiomarkerisanaturallyoccurring,measurablesubstanceorconditioninthebodythatreliablyindicatesthepresenceorabsenceofdiseaseortheriskoflaterdevelopingadisease;
forexample,bloodglucoselevelsareabiomarkerofdiabetes,andcholesterollevelsareabiomarkerofcardiovasculardiseaserisk.BothfluidandimagingmeasuresarebeingtestedaspossiblebiomarkersforAlzheimer’s.(Seesupplement4.)
Therewasabroadconsensuswithintheworkgroupsthatmuchadditionalresearchneedstobedonetovalidatetheapplicationofbiomarkersastheyareproposedinthenewly-publishedarticles.Accordingtotheauthors,“Thedefinitivestudies…arelikelytotakemorethanadecadetofullyaccomplish.Thus,wemustmovequickly…andadjustourmodelsandstudydesignsasnewdatabecomeavailable.”
“IfwecandefinitivelydeterminetheriskofdevelopingAlzheimer’sdementiainpeoplewhohavebiomarkerevidenceofbrainchangesbutarenotshowingoutwardsymptoms,wewillopenanimportantwindowofopportunitytointervenewithdisease-modifyingtherapies,oncetheyaredeveloped,”Thiessaid.
“Inaddition,thenewcriteriagiveuspowerfultoolstoaccelerateourknowledgeinthefightagainstAlzheimer’sdisease.TheygiveusguidelinesforgettingamoreaccurateassessmentofAlzheimer’sprevalence.Inthatwaywecanbetterassesstheneedforeverythingfromresearchdollarstocareservices,topatientandcaregivereducationmaterials,tonursinghomebeds,tothenumberofgerontologistsandnursesthatweneed.And,theygiveusabasisforcreatingthenextgenerationofAlzheimer’streatmentsthatwillbeeffectiveineachstageofthedisease,”Thiessaid.
MovingtheFieldTowardEarlierDiagnosisandTreatmentofAlzheimer’s
TheAlzheimer’sAssociation,inits2010reporttitled“ChangingtheTrajectoryofAlzheimer’sDisease:
ANationalImperative,”showedthatahypotheticalinterventionthatdelayedtheonsetofAlzheimer’sdementiabyfiveyearswouldresultinanearly45percentreductioninthenumberofpeoplewithAlzheimer’sby2050,andreducetheprojectedMedicarecostsofAlzheimer’sfrom$627billionto$344billiondollars.
Theauthorsofthenewly-releasedarticleswrite,“ItisourhopethattheadvancesinpreclinicaldetectionofAlzheimer’swillenableearlier,moreeffectivetreatment,justasnearlyalloftherapeuticgainsincancer,cardiovasculardisease,osteoporosis,anddiabetesinvolvetreatmentbeforesignificantclinicalsymptomsarepresent.Screeningandtreatmentprogramsinstitutedforotherdiseases…havealreadybeenassociatedwithadecreaseinmortalityduetotheseconditions.”
Thiesadds,“Currently,Alzheimer’stherapiesareindevelopmentthatmaybeabletosloworstoptheprogressionofthedisease.Byimprovingearlydetectionandriskevaluation,wewillbetterbeabletotestpotentialtherapiesandeventuallyprescribethemforpeopleatincreasedrisk.Ultimately,thisapproachenvisionsforAlzheimer’swhatisnowcommonpracticeincardiovasculardisease,whereearlysignsofrisk–forexample,ingeneticmarkersorinbloodcholesteroland/orbloodpressurelevels–canbetreatedtoreducethelikelihoodofheartattackorstrokelateron.”
ThechallengeforAlzheimer’snowisthatthereiscurrentlynosingle,generallyacceptedwaytoidentifythediseaseintheearlieststage–beforesymptomsareevident.ItishopedthattheresearchagendaoutlinedinthenewpreclinicalAlzheimer’sarticlewillcorrectthisdeficit.
PresymptomaticDiseaseDetectionandTreatment–NotaNewIdea,ExceptinAlzheimer’s
Accordingtotheauthors,“Theconceptofapreclinicalphaseofdiseaseshouldnotbetooforeign.Medicalprofessionalsreadilyacknowledgethatcancercanbedetectedatthestageof‘carcinomainsitu’andthathypercholesterolemiaandatherosclerosiscanresultinnarrowingofcoronaryarteriesthatisdetectablepriortomyocardialinfarction.Itiswidelyacknowledgedthatsymptomsarenotnecessarytodiagnosehumandisease.TypeIIdiabetes,hypertension,renalinsufficiency,andosteoporosisarefrequentlydetectedthroughlaboratorytests,andeffectivetreatmentcanpreventtheemergenceofsymptoms.”
“WeshouldbeopentotheideathatAlzheimer’scouldonedaybediagnosedpreclinicallybythepresenceofbiomarkerevidence,whichmayeventuallyguidetherapypriortotheonsetofsymptoms.Wetreatpeoplewithdiabetes,elevatedcholesterol,hypertensionandavarietyofotherillnesses–wedonotwaitforstrokes,heartattacksorotherlongtermcomplicationsthatweknowwilloccurinsignificantnumbersofthoseaffected.Similarly,ourintentionistousethesecriteriatobetterdetermineanindividual’sriskofdevelopingAlzheimer’sdisease.Thisdiagnosticresearchwillhelpusdiscoverthedrugsofthefutureandprepareforthedaywhenwecanadmin