Stem Cells Reverse Diabetes in Mice

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日期: 2003-07-23 今日/总浏览: 1/567! }' O& n5 z+ T7 R: h" r: \) O
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Bone marrow stem cells (green) induce the regeneration of insulin-producing islet cells of the pancreas (red) in mice. Scale bar, 50 micrometers.Nonobese diabetic mouse.
! I2 h7 d7 Y, y; T1 lResearchershavecureddiabetesinmicebyinjectingbonemarrowstemcellsintothebloodstream.Thestemcellsseekoutdamagedtissueinthepancreas,wheretheyappeartotriggerthegrowthofnewcells.Ifbonemarrowstemcellshavethesameeffectinhumanswithdiabetes,theycouldbeusedtotreatpatientsstraightaway.% x! K! t3 @) r* m2 G" R% e
“Thisisaverysignificantstudy,”saysJoelHabenerofHarvardMedicalSchoolinBoston,whostudiesstemcellsinthepancreas.“Itsuggeststhatthereissomethinginthebonemarrowthatcanstimulatethepancreaticstemcellstoregenerate.”" O0 S* K! J- g5 s* O  G: p
Itcantakedecadestobringanewdrugtothemarketplace.Butbonemarrowtransplantshavebeenusedforyearstotreatahostofblooddisorders,includingleukemiaandsicklecelldisease.Theyhavebeenprovensafeandwouldrequirenogovernmentapprovalforuseasapossiblediabetestreatmentinhumans.) I* S+ V6 l: c: i8 k
“There’snothingtopreventpeoplefromtryingthisinhumans,”saysHabener.“Peoplewithdiabeteshavebeenwaitingforacureforyearsandyears.Whynotgoaheadandtry?”
& f! ?  P- b( K3 ?0 R4 ]Diabetes,whichaffects150millionpeopleworldwide,occurswhenthepancreasdoesnotproduceenoughinsulinorwhencellsofthebodybecomeresistanttoinsulin.Asaresult,glucoseaccumulatesinthebloodstream,leadingtoseverecomplications,includingheartdisease,nervedamage,stroke,blindness,andkidneyfailure.
, Q$ w  e7 {" F& z& P. w' h: xInthenewstudy,MickieBhatiaandhiscolleaguesatRobartsResearchInstituteinLondon,Ontario,firsttreatedmicewithadrugthatdestroysthepancreasandmakesthemdiabetic.Thediabeticmicehadlowlevelsofinsulinandhighlevelsofglucoseintheirblood.
  @) r( T/ d  S( [9 O0 MButwhentheresearchersinjectedthemicewithbonemarrowstemcells,thesymptomsofdiabetesreversedwithin2weeks.Insulinlevelsroseandbloodglucoselevelsfelltonear-normalvalues.
7 j  ^% T- \0 |, i6 i% g1 LLabelingofthedonorcellsrevealedthatthenewcellgrowthhadcomefromcellsalreadywithinthepancreas,notfromtheinjectedcells., a2 P. J3 y8 V& s: p  D
“Wealmostdidn’tbelievetheresultsourselves,”saysBhatia.“Wehavehadtheresultsforafewyears,butheldbackpublishingthem.Butit’saconsistentrobusteffect.”
3 {. Y0 R( l% i, S: TTheresearchersalsofoundthattheinjectedbonemarrowcellstriggerednewgrowthonlyindamagedpancreatictissue.Inmicewithintactpancreases,noregenerationoccurred.
7 ^& q& k7 w. H3 M4 z9 J" C“Bonemarrowcellsonlygotothepancreasifit’sinjured,”saysBhatia.“Somethingattheinjurysitecausesthestemcellstohomeintothedamagedpancreas.Wehavenoideawhatthatcouldbe.”
) e" m# ~5 x) G8 ^' G7 Y$ _/ eOtherstudieshaveshownrecentlythatbonemarrowstemcellscanbecomedifferentkindsofcellsinthebody,includingheart,liver,pancreas,andnerve.Butthesefindingshavebeencontroversial.Someexperimentssuggestthatthestemcellscanthemselvesbeturnedintodifferenttypesofcells,whileotherssuggestthatthechangeoccursbecausethecellsfusetoformhybridcells.
0 g) r" ]7 O% z/ g+ W, N: lBhatia’sstudyisdifferentbecauseitsuggeststhatthebonemarrowstemcellsdonotthemselvesbecomepancreascells.Instead,thecellssomehowstimulatenewgrowthincellsthatarealreadyinthepancreas.
$ n- ]0 c( a4 oJusthowthisoccursisnotknown,butHabenerbelievesthatbonemarrowcellsaresecretingsomekindofsignalthattellsstemcellsinthepancreastogrow.
! m. y  l  L' m4 A& @- W7 _Ifresearcherscouldisolatethesubstancethattriggerstheregenerationofpancreascellstotreatdiabetes,itcouldbegivendirectlytopatients,thusavoidingtransplants.4 v, a8 a' X/ N& C
“Wecouldjustgiveashotofthisstemcellstimulator,andthepancreascouldmakenewcells,”saysHabener.“Itwouldbeawonderfulwaytotreatthedisease.”
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! t% ]# g3 [) w% ?作者: Nancy Touchette& ]+ q) D6 w% G% b/ x7 z; v
来源: Genome News Network( Q4 A, K, v& J' C* W- m
发布者: 刘斌