From:  Stem cell therapy in neurological disorders: promises and concerns

 Preclinical and clinical studies of stem cell transplantation in neurological disorders

Type of stem cellsNeurological disordersReferencesModelsAdministration’s routeQuantity of stem cellsEffectsRisks
NSCsParkinson’s disease[41, 44]RatsIV, IC2 × 106 cellsAmeliorated Parkinson dyskinesia and promoted neurogenesisRisk of cancer development
Huntington’s disease[96]Primate, ratsTransplanted into brain5 × 104–1 × 106 cellsReduction of lesion size and proliferation in the striatum
Stroke[45]MiceTransplanted into brain2 × 105 cellsImproved sensorimotor functioning and reduced infarct size
[97]HumanIC2 × 106 cellsIt has been shown to be safe and effective in improving NIHSS scale
IVEscalation dose from 3 × 105–1 × 107 cellsInduces neurogenesis in the human brain
TBI[46]MiceTransplanted into brain2.5 × 105–2 × 107 cellsEarly transplant showed an enhanced functional recovery, while a delayed transplantation seems to be more controversial
Amyotrophic lateral sclerosis[47]Mice, ratsIV2.5 × 105–1 × 106 cellsIncreased life span, improvement in motor neuron survival and slow down disease progression
[98]HumanTransplanted in the spinal cord, transplanted in the motor frontal cortex5 × 106–1.6 × 107 cellsImproved the life span and reduced disease progression
Alzheimer’s disease[99]Rats, miceTransplanted into brainRats: 1 × 105–1 × 106 cells; mice: 1.5 × 104 cellsEnhanced synaptogenesis and improved learning and memory
ESCsParkinson’s disease[100]Mice, rats, monkeyICMice: 1.5 × 105 cells; rats: 2.5 × 105 cells; monkey: 7.5 × 106 cellsNeuroprotection and neurogenesisTumor formation; ethical issue
Huntington’s disease[101]MiceTransplanted into brain1 × 105 cellsReduction in cerebral lesion size and proliferation in the striatum
Multiple sclerosis[101]Mice, ratsIntraventricular1 × 106 cellsConsistent beneficial effect
HumanIVNot specifiedInconsistent results
Alzheimer’s disease[19, 20, 102]Mice, ratsTransplanted into brain1 × 105–1 × 106 cellsImproved learning and memory
iPSCs Parkinson’s disease[103]MiceTransplanted into brain1.5 × 105 cellsNeuroprotective and neurogenesisRisk of cancer and teratoma formation
Huntington’s disease[45, 104, 105]RodentIV, transplanted into brain1 × 106 cellsMigration to striatum and differentiation into glial cells
TBI[56]RatsIV2 × 106–1 × 107 cellsLong-term improvement in spatial learning and attenuation of neuroinflammation
Amyotrophic lateral sclerosis[57]MiceIn culture cells as well as in mice1 × 106 cellsIncreased life span
Alzheimer’s disease[26]Transgenic miceTransplanted into brainNot specifiedReduction of brain amyloid beta
MSCsParkinson’s disease[36]HumanIV1 × 106 cellsExert therapeutic effect by protecting dopaminergic neurons and maintaining the nigrostriatal pathwayShort survival time of the cells; homing issues
[106]MiceTransplanted into brainNot specifiedSubjective improvement of the gait and the facial symptoms
Stroke[66]Mice, ratsIC, IV1 × 108 cellsImproved sensorimotor functioning and reduced infarct size
[67]HumanIV
TBI[107]RatsTransplanted into brain3 × 105–4 × 106 cellsReduced inflammatory cytokines, reactive astrogliosis, and edema
Amyotrophic lateral sclerosis[38, 108]Human, miceIV1.7 × 107 cellsPositive safety outcome and increased life span
Multiple sclerosis[48]Mice, ratsTransplanted into brain2 × 107 cellsAlleviated symptoms and positive effect on cytokines
[38]HumanIV2.5 × 106 cellsSafe and improvement of symptoms
Alzheimer’s disease[35]MiceIntracerebroventricular, IC, IVNot specifiedImproved cognitive function and reduced amyloid beta
SCI[64]RatsIC, IVNot specifiedImprove motor recovery
[51]HumanIV8 × 105–4 × 108 cellsImprove sensory and motor score
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IV: intravenous; NIHSS: National Institutes of Health Stroke Scale