Stem Cells Reverse Diabetes in Mice

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日期: 2003-07-23 今日/总浏览: 1/567& M+ J& o! q. r4 T6 g+ R" |

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) m# V* U0 G2 qBone 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.
3 @( q" i0 i0 K6 A; N" IResearchershavecureddiabetesinmicebyinjectingbonemarrowstemcellsintothebloodstream.Thestemcellsseekoutdamagedtissueinthepancreas,wheretheyappeartotriggerthegrowthofnewcells.Ifbonemarrowstemcellshavethesameeffectinhumanswithdiabetes,theycouldbeusedtotreatpatientsstraightaway.
2 v0 J8 r& G& V% V- E- K) Y“Thisisaverysignificantstudy,”saysJoelHabenerofHarvardMedicalSchoolinBoston,whostudiesstemcellsinthepancreas.“Itsuggeststhatthereissomethinginthebonemarrowthatcanstimulatethepancreaticstemcellstoregenerate.”; K) @5 B; X/ Q) l0 Y" p" x
Itcantakedecadestobringanewdrugtothemarketplace.Butbonemarrowtransplantshavebeenusedforyearstotreatahostofblooddisorders,includingleukemiaandsicklecelldisease.Theyhavebeenprovensafeandwouldrequirenogovernmentapprovalforuseasapossiblediabetestreatmentinhumans.5 D3 c) X3 j  R0 r5 m5 M
“There’snothingtopreventpeoplefromtryingthisinhumans,”saysHabener.“Peoplewithdiabeteshavebeenwaitingforacureforyearsandyears.Whynotgoaheadandtry?”
- }9 W; H, X4 [* Z. g7 U( v. RDiabetes,whichaffects150millionpeopleworldwide,occurswhenthepancreasdoesnotproduceenoughinsulinorwhencellsofthebodybecomeresistanttoinsulin.Asaresult,glucoseaccumulatesinthebloodstream,leadingtoseverecomplications,includingheartdisease,nervedamage,stroke,blindness,andkidneyfailure.
' j! ^8 }) Z% s! p# MInthenewstudy,MickieBhatiaandhiscolleaguesatRobartsResearchInstituteinLondon,Ontario,firsttreatedmicewithadrugthatdestroysthepancreasandmakesthemdiabetic.Thediabeticmicehadlowlevelsofinsulinandhighlevelsofglucoseintheirblood.; y# o+ V* H" ]% F, _3 Y) g/ o
Butwhentheresearchersinjectedthemicewithbonemarrowstemcells,thesymptomsofdiabetesreversedwithin2weeks.Insulinlevelsroseandbloodglucoselevelsfelltonear-normalvalues., e2 }$ k; V, R9 s& o( V! c  l
Labelingofthedonorcellsrevealedthatthenewcellgrowthhadcomefromcellsalreadywithinthepancreas,notfromtheinjectedcells.
4 [1 A! ~) R0 p6 a0 v+ }1 o. C“Wealmostdidn’tbelievetheresultsourselves,”saysBhatia.“Wehavehadtheresultsforafewyears,butheldbackpublishingthem.Butit’saconsistentrobusteffect.”5 x6 e( Y+ k) e; b3 ^
Theresearchersalsofoundthattheinjectedbonemarrowcellstriggerednewgrowthonlyindamagedpancreatictissue.Inmicewithintactpancreases,noregenerationoccurred.2 g. N" m& x$ Q7 P% L. h; ^9 g
“Bonemarrowcellsonlygotothepancreasifit’sinjured,”saysBhatia.“Somethingattheinjurysitecausesthestemcellstohomeintothedamagedpancreas.Wehavenoideawhatthatcouldbe.”6 t/ g5 q, Q- ?3 N- @2 f$ r% i
Otherstudieshaveshownrecentlythatbonemarrowstemcellscanbecomedifferentkindsofcellsinthebody,includingheart,liver,pancreas,andnerve.Butthesefindingshavebeencontroversial.Someexperimentssuggestthatthestemcellscanthemselvesbeturnedintodifferenttypesofcells,whileotherssuggestthatthechangeoccursbecausethecellsfusetoformhybridcells.
( s$ L6 _, e& D% s: ~Bhatia’sstudyisdifferentbecauseitsuggeststhatthebonemarrowstemcellsdonotthemselvesbecomepancreascells.Instead,thecellssomehowstimulatenewgrowthincellsthatarealreadyinthepancreas.2 Q& `0 O; A9 K; F4 l% M+ ^
Justhowthisoccursisnotknown,butHabenerbelievesthatbonemarrowcellsaresecretingsomekindofsignalthattellsstemcellsinthepancreastogrow.; x0 n2 [& F) Z" H
Ifresearcherscouldisolatethesubstancethattriggerstheregenerationofpancreascellstotreatdiabetes,itcouldbegivendirectlytopatients,thusavoidingtransplants.8 M9 s2 }1 B% U1 L/ l; y
“Wecouldjustgiveashotofthisstemcellstimulator,andthepancreascouldmakenewcells,”saysHabener.“Itwouldbeawonderfulwaytotreatthedisease.”  Q  W: A1 `& I" u2 N' B1 \' Z
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, f6 E- |1 Z* g* Y8 W8 s0 u作者: Nancy Touchette$ u2 ^' v. Z! a/ T$ B2 u" q5 e
来源: Genome News Network
- X# U5 y/ u4 N8 i6 |发布者: 刘斌