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Neurogenesis and transplantation in stroke-damaged brain

Darsalia, Vladimer LU (2007)
Abstract (Swedish)
Popular Abstract in Swedish

Stroke hos unga vuxna råttor och möss utlöser neurogenes i den skadade regionen striatum samt i den intakta hippocampus, men eftersom stroke framförallt drabbar äldre individer, är det av största vikt att utröna åldrandets effekt på hjärnans mekanismer för återhämtning. Gamla och unga vuxna råttor inducerades med stroke genom transient ocklusion av mellersta hjärnartären (middle cerebral artery occlusion, MCAO) och delande celler märktes in med den mitotiska markören BrdU genom intraperitoneal administrering. Djuren perfunderades 7 veckor efter infarkten och nybildade cellers uttryck av BrdU tillsammans med neuronala och gliamarkörer undersöktes med epifluorescent och konfokalt mikroskop. Unga... (More)
Popular Abstract in Swedish

Stroke hos unga vuxna råttor och möss utlöser neurogenes i den skadade regionen striatum samt i den intakta hippocampus, men eftersom stroke framförallt drabbar äldre individer, är det av största vikt att utröna åldrandets effekt på hjärnans mekanismer för återhämtning. Gamla och unga vuxna råttor inducerades med stroke genom transient ocklusion av mellersta hjärnartären (middle cerebral artery occlusion, MCAO) och delande celler märktes in med den mitotiska markören BrdU genom intraperitoneal administrering. Djuren perfunderades 7 veckor efter infarkten och nybildade cellers uttryck av BrdU tillsammans med neuronala och gliamarkörer undersöktes med epifluorescent och konfokalt mikroskop. Unga och åldrade råttor uppvisade liknande ökning av antalet nya nervceller i striatum, trots att den basala proliferationen var minskad i subventrikulärzonen hos de gamla djuren. Däremot var både basal proliferation och nybildning av antalet nervceller hos de gamla djuren signifikant reducerade i subgranulärzonen och granulära cellagret i hippocampus. Den här studien visar att basal neurogenes är försämrad hos de gamla jämfört med de unga djuren, men att hjärnan svarar på skada med en ökad neurogenes. Ökningen var likvärdig i striatum hos både unga och gamla djur, vilket visar på en möjlig självrepareringsmekanism även hos den gamla hjärnan.



Transplantation av stamceller anses vara en terapeutisk benhandlingsmetod för strokepatienter i framtiden. För att kunna utveckla en framgångsrik terapi är det dock nödvändigt att identifiera och karaktärisera användbara neurala stamcellslinjer. Neurala stamceller (Neural Stem Cells, NSCs) från aborterade fosters striatum och kortex studerades och deras neurogena kapacitet in vitro och efter transplantation till hjärnor hos intakta neonataler och vuxna stroke-skadade djur jämfördes. NSCs, expanderade som neurosfärer, från kortex och striatum skilde sig inte från varandra gällande kapacitet att proliferera, tillväxthastighet, sekundär sfärformation eller uttryck av generella neurala markörer. Emellertid producerade kortikala NSCs fler glutamaterga, tyrosin hydroxylas- och kalretininpositiva nervceller till skillnad mot kulturer med striatala NSCs där fler nervceller uttryckte markör för striatala projektionsneuron, DARPP-32. Humana kortikala och striatala NSCs överlevde och migrerade lika bra efter transplantation till nyfödda råttor. Båda NSCs-typerna genererade lika många mogna NeuN+ nervceller, vilka var åtskilligt fler vid 4 månader jämfört med 1 månad efter implantation. Vid 4 månader innehöll transplantatet celler med morfologi kännetecknande för nervceller, astrocyter och oligodendrocyter, där majoriteten av nervcellerna uttryckte parvalbumin.



Striatala och kortikala NSCs överlevde transplantation till vuxna djur inducerade med stroke lika bra (30%) 1 månad efter implantation och båda celltyperna migrerade genom hela striatum. Striatala NSCs migrerade längst och upptog en större del av striatum. I kärnan av transplantatet var cellerna odifferentierade, så gott som samtliga uttryckte cellulära markörer för outvecklad neural linje såsom nestin samt till en mindre grad även GFAP, ?III-tubulin, DCX och kalretinin. Immunocytokemi med markörer för proliferation (p-H3 och Ki67) avslöjade att transplanterade striatala och kortikala NSCs upphör att dela sig. Humana celler utanför transplantatets kärna differentierade, uppvisade mogen nervcellsmorfologi och uttryckte adulta nervcellsmarkörer som HuD, kalbindin och parvalbumin. Intressant nog så genererade de striatala NSCs fler parvalbumin+ och kalbindin+ nervceller och praktiskt taget inte några av de transplanterade cellerna differentierade till astrocyter eller oligodendrocyter. Baserat på dessa resultat kan humana fetala striatum- och kortexderiverade NSCs komma att anses som säkra och användbara källor av celler med stor neurogen potential, vilken måste undersökas vidare i djurmodeller för stroke. (Less)
Abstract
Stroke in young adult rodents triggers neurogenesis in the damaged striatum and intact hippocampus. as stroke happens frequently in aged individuals it is of great importance to know whether aging affects brain recovery mechanisms. Aged and young adult rats were subjected to stroke by transient occlusion of the middle cerebral artery and proliferating cells were labeled by intraperitoneal administration of the mitotic marker BrdU. Animals were sacrificed at 7 weeks after infarct and new cells were examined for expression of BrdU and neuronal and glial markers with epifluorescent and confocal microscopy. Young and aged rats showed similarly increased number of new neurons in the striatum, although basal proliferation was reduced in the aged... (More)
Stroke in young adult rodents triggers neurogenesis in the damaged striatum and intact hippocampus. as stroke happens frequently in aged individuals it is of great importance to know whether aging affects brain recovery mechanisms. Aged and young adult rats were subjected to stroke by transient occlusion of the middle cerebral artery and proliferating cells were labeled by intraperitoneal administration of the mitotic marker BrdU. Animals were sacrificed at 7 weeks after infarct and new cells were examined for expression of BrdU and neuronal and glial markers with epifluorescent and confocal microscopy. Young and aged rats showed similarly increased number of new neurons in the striatum, although basal proliferation was reduced in the aged subventricular zone. In contrast, both basal proliferation and the generation of new neurons was significantly reduced in aged subgranular zone and granule cell layer of the hippocampus. This study shows that basal neurogenesis is impaired in the aged rat brain compared to young, but the brain responds to damage with increased neurogenesis. This increase was similar in the striatum of both young and old animals, indicating the existence of potential self-repair mechanisms in the aged brain.



Stem cell transplantation is considered one of the future therapeutic methods for treatment of stroke. Therefore identification and characterization of viable neural stem cell lines is essential for the development of successful therapies. Neural stem cells (NSCs) isolated from fetal human striatum and cortex were studied and compared for their neurogenic capacity in vitro and after transplantation in neonatal intact or adult, stroke-damaged brain. Cortex- and striatum-derived NSCs expanded as neurospheres did not differ in proliferative capacity, growth rate, secondary sphere formation, and expression of general neural markers. However, whereas cortical NSCs produced higher number of glutamatergic and tyrosine hydroxylase- and calretinin-positive neurons, several-fold more neurons expressing the striatal projection neuron marker, DARPP-32, were observed in cultures of striatal NSCs. Human cortical and striatal NSCs survived and migrated equally well after transplantation in neonatal rats. The two NSC types also generated similar numbers of mature NeuN+ neurons, which were several-fold higher at 4 months as compared to at 1 month after grafting. At 4 months, the grafts contained cells with morphological characteristics of neurons, astrocytes, and oligodendrocytes, the majority of neurons expressing parvalbumin.



Striatal and cortical NSCs exhibited similar robust survival (30%) at 1 month after transplantation in stroke-subjected animals and migrated throughout the damaged striatum. Striatal NSCs migrated longer distance and occupied a bigger volume of striatum. In the transplantation core, cells were undifferentiated, virtually all expressing cellular markers of immature neural lineage such as nestin, and to lesser extent also GFAP, ?III-tubulin, DCX and calretinin. Immunocytochemistry with proliferation markers (p-H3 and Ki67) revealed that grafted striatal and cortical NSCs cease to proliferate. Human cells outside the transplantation core differentiated, exhibited mature neuronal morphology and expressed adult neuronal markers such as HuD, calbindin and parvalbumin. Interestingly, striatal NSCs generate greater number of parvalbumin+ and calbindin+ neurons and virtually none of the grafted cells differentiated into astrocytes or oligodendrocytes. Based on these data, human fetal striatum- and cortex-derived NSCs could be considered safe and viable sources with strong neurogenic potential for further exploration in animal models of stroke. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Eriksson, Peter, Göteborg
organization
publishing date
type
Thesis
publication status
published
subject
keywords
neuropsykologi, neuropsychology, neurophysiology, Neurologi, Neurology, Stroke, Transplantation, Stem cells, Aging, Neurogenesis, neurofysiologi
pages
118 pages
publisher
Lund University
defense location
N/A
defense date
2007-05-26 09:00
ISSN
1652-8220
ISBN
978-91-85559-71-8
language
English
LU publication?
yes
id
119b027d-8f84-4671-9c61-da7d57452f19 (old id 548666)
date added to LUP
2007-09-10 15:36:27
date last changed
2016-09-19 08:44:58
@phdthesis{119b027d-8f84-4671-9c61-da7d57452f19,
  abstract     = {Stroke in young adult rodents triggers neurogenesis in the damaged striatum and intact hippocampus. as stroke happens frequently in aged individuals it is of great importance to know whether aging affects brain recovery mechanisms. Aged and young adult rats were subjected to stroke by transient occlusion of the middle cerebral artery and proliferating cells were labeled by intraperitoneal administration of the mitotic marker BrdU. Animals were sacrificed at 7 weeks after infarct and new cells were examined for expression of BrdU and neuronal and glial markers with epifluorescent and confocal microscopy. Young and aged rats showed similarly increased number of new neurons in the striatum, although basal proliferation was reduced in the aged subventricular zone. In contrast, both basal proliferation and the generation of new neurons was significantly reduced in aged subgranular zone and granule cell layer of the hippocampus. This study shows that basal neurogenesis is impaired in the aged rat brain compared to young, but the brain responds to damage with increased neurogenesis. This increase was similar in the striatum of both young and old animals, indicating the existence of potential self-repair mechanisms in the aged brain.<br/><br>
<br/><br>
Stem cell transplantation is considered one of the future therapeutic methods for treatment of stroke. Therefore identification and characterization of viable neural stem cell lines is essential for the development of successful therapies. Neural stem cells (NSCs) isolated from fetal human striatum and cortex were studied and compared for their neurogenic capacity in vitro and after transplantation in neonatal intact or adult, stroke-damaged brain. Cortex- and striatum-derived NSCs expanded as neurospheres did not differ in proliferative capacity, growth rate, secondary sphere formation, and expression of general neural markers. However, whereas cortical NSCs produced higher number of glutamatergic and tyrosine hydroxylase- and calretinin-positive neurons, several-fold more neurons expressing the striatal projection neuron marker, DARPP-32, were observed in cultures of striatal NSCs. Human cortical and striatal NSCs survived and migrated equally well after transplantation in neonatal rats. The two NSC types also generated similar numbers of mature NeuN+ neurons, which were several-fold higher at 4 months as compared to at 1 month after grafting. At 4 months, the grafts contained cells with morphological characteristics of neurons, astrocytes, and oligodendrocytes, the majority of neurons expressing parvalbumin.<br/><br>
<br/><br>
Striatal and cortical NSCs exhibited similar robust survival (30%) at 1 month after transplantation in stroke-subjected animals and migrated throughout the damaged striatum. Striatal NSCs migrated longer distance and occupied a bigger volume of striatum. In the transplantation core, cells were undifferentiated, virtually all expressing cellular markers of immature neural lineage such as nestin, and to lesser extent also GFAP, ?III-tubulin, DCX and calretinin. Immunocytochemistry with proliferation markers (p-H3 and Ki67) revealed that grafted striatal and cortical NSCs cease to proliferate. Human cells outside the transplantation core differentiated, exhibited mature neuronal morphology and expressed adult neuronal markers such as HuD, calbindin and parvalbumin. Interestingly, striatal NSCs generate greater number of parvalbumin+ and calbindin+ neurons and virtually none of the grafted cells differentiated into astrocytes or oligodendrocytes. Based on these data, human fetal striatum- and cortex-derived NSCs could be considered safe and viable sources with strong neurogenic potential for further exploration in animal models of stroke.},
  author       = {Darsalia, Vladimer},
  isbn         = {978-91-85559-71-8},
  issn         = {1652-8220},
  keyword      = {neuropsykologi,neuropsychology,neurophysiology,Neurologi,Neurology,Stroke,Transplantation,Stem cells,Aging,Neurogenesis,neurofysiologi},
  language     = {eng},
  pages        = {118},
  publisher    = {Lund University},
  school       = {Lund University},
  title        = {Neurogenesis and transplantation in stroke-damaged brain},
  year         = {2007},
}