Stem Cell Study May Aid Diabetics

韩雪娜

日期: 2002-11-20 今日/总浏览: 1/653
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: T5 {7 F" a: J% E0 [Embryonicstemcellswereturnedintoinsulin-makingtissuethatwasabletokeepdiabeticmicealiveinanexperimentthatexpertssayisanimportantsteptowardanewtreatmentfordiabetes.
! |7 p" Q! l1 q2 Z# e1 r1 wResearcherscautionedthatthetechniquewasnotyetreadyfortestinginhumans,butsaiditcouldleadeventuallytousingembryonicstemcellstomakenewinsulin-producingislets.TheisletsofLangerhansaregroupsofcellsinthepancreas,includingthebetacellsthatproduceinsulin.) v& Y$ w1 K8 y) d
InastudyappearingthisweekintheProceedingsoftheNationalAcademyofSciences,StanfordUniversityresearcherssaytheyculturedmouseembryonicstemcellsuntiltheydevelopedintoatissuethatmadeinsulin.Aftertheyputthetissueintodiabeticmice,theanimalsweresustainedbytheinsulinproducedbythetissuegraft.% U* o8 k) e! j7 Y
We'vemadesomethingthatsharesseveralimportantpropertieswiththebetacells,butwehavenotmadebetacells,saidIngridC.Rulifson,afirstauthorofthestudy.Webelievethisisthefurthestanyonehasgone(inmakinginsulin-producingcellsfromembryonicstemcells).Thefactthatwewereabletoachieverescuesurvivalinthesemicehasn'tbeendemonstratedbeforeinthisway.
9 W/ r. B7 |9 j2 GDr.RobertGoldstein,chiefscientificofficerfortheJuvenileDiabetesResearchFoundationInternational,saidtheStanfordfindingisasignificantadvanceindiabetesresearchusingembryonicstemcells,buthesaiditwillhavenoimmediatehumanapplication.
4 S- J# ]* J0 i0 x8 R2 X* xTheprincipleofbeingabletotakeembryonicstemcellsandreversediabetesisanextremelyimportantobservation,saidGoldstein.Hesaidresearchersultimatelyhopetouseembryonicstemcellstomakenewbetacellsthatcouldbetransplantedintodiabeticsandproducenormallevelsofinsulin.& ^7 |4 f/ G$ F# N* g. Y* ^
HecalledtheStanfordstudyoneofthenecessarystepstowardachievingthisgoal,butemphasizedthatthenextsteps—translatingthemousedataintohumantherapy—couldtakemanyyears.- H" S" {5 P! _/ e
Wecan'tfixpeopletomorrow,saidGoldstein.
% d$ e( W0 Y6 W5 q' a2 T0 m( c1 NEmbryonicstemcellsaretheancestralcellsfromwhichallthetissueinthebodydevelops.Scientistsbelievethatiftheycanlearnhowtodirectthetransformationofembryonicstemcellstheywillbeabletogrowfreshcellstoreplacethosethathavediedorstoppedfunctioning.
1 d, M% ~6 p# S+ CSomeformsofdiabetesarecausedbythedeathormalfunctioningofthebetacellsthatmakeinsulin,ahormoneessentialforregulatingsugarintheblood.Researchershopetousehumanembryonicstemcellstogrownewbetacells,whichcouldthenbegraftedintodiabeticpatientstonormalizethemetabolismofsugar.
, l- b/ E  |" ~8 z# iIntheStanfordstudy,researchersusedspecialchemicalstocausemouseembryonicstemcellstotransformintocellmassesthatresembledpancreaticislets.Test-tubeexperimentsshowedthatthecellsmadeinsulin.
+ }+ K/ R; M. kTheresearchersthenusedchemicalstokillthebetacellsinagroupoflaboratorymice,turningthemiceintodiabetics.Thescientiststhengraftedsomeoftheinsulin-producingtissueintotheanimals.Thetransplantedtissuemadeinsulin,respondingtothelevelsofsugarinthebloodstreamofthemice,andkeptthemicealive.$ d% M" p1 }  t; B) c
Controlmice,whichhaddiabetesbutdidnotreceivethegraft,died.
: W0 v& }- c! A/ {Toprovethatitwasthetransplantedtissuethatwasmakingtheinsulin,theresearchersremovedthegraftsafterthreeweeks.Themicesoondiedfromexcesssugarintheblood.# c+ Y) N9 y6 J* i8 V4 f
Atleastforashortperiod,weextendedthelifeoftheseanimalsconvincinglyandshowedthatuponremovalofthegrafttheanimalssufferedsevererelapseofthedisease,saidSeungK.Kim,aStanfordresearcherandseniorauthorofthestudy.
8 |0 M3 e0 N9 Y  j* t/ uKimsaidthatthetransplantedtissueproducedinsulinatonly10percentto12percentofthelevelsinnormalmiceanddidnotproducesomeoftheotherhormonesorfactorsmadebythenormalbetacell." ]% L; X# Z4 b  c: i" M' i) X4 ]" x
Thisisonestepintherightdirection,saidKim.Headdedthatwehavealongwaytogobeforehumandiabeticscanbetreatedwithtissuefromembryonicstemcells.; }2 `& N! I# B2 Z: F

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# {7 L# G6 b( }OntheNet:
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) b2 y6 T, A1 I2 g) @# t" w4 OProceedingsoftheNationalAcademyofSciences:http://www.pnas.org/: D: r% @( g9 V" J8 u8 }, o* B

$ p5 w) R1 U( A9 KJuvenileDiabetesFoundationInternational:http://www.jdrf.org* S5 s. L& S1 d# [

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1 c* s) C4 J3 D; f2 l作者: PAUL RECER+ h$ k8 N8 g. r/ }8 @* K5 }
来源: AP Science
/ h6 |9 p! g* e2 d2 B发布者: 刘斌