Adult human neural stem cell therapeutics: Current developmental status and prospect

Table 1 Isolation and in vitro culture methods for adult neural stem cells

Culture methods	Cell source	Dissociating method	Media composition	Plate coating	Maximal in vitro culture	Ref.
Adherent culture method	Temporal lobe	Physical Mincing and enzymatic digestion with papain	DMEM/F12 supplemented with 10 ng/mL bFGF, 20 ng/mL TGFα, 2.5 μg/mL heparin, 2% B27 (without retinoic acid), 10 mmol/L hepes, and 1% FBS			[54]
	Temporal lobe	Mechanical trituration and enzymatic dissociation using papain and DNase I	DMEM/F12 supplemented with 1% B27, 50 ng/mL EGF, 50 ng/mL bFGF, and 0.5% FBS	Poly-L-ornithine	18 passages	[18]
Neurosphere culture method	Hippocampal and lateral ventricle wall tissue	Mechanical dissociation and enzyme digestion using hyaluronic acid, kynurenic acid, and trypsin	DMEM/F12 supplemented with 10 ng/mL EGF, 20 ng/mL EGF, B27, and 2 mmol/L glutamine			[39]
	Temporal lobe	Enzymic digestion with trypsin	N2 medium supplemented with 5% FBS	Poly-2-hydroxyethyl methacrylate		[40]
	Hippocampus Amygdala Frontal cortex Temporal cortex	Enzymic digestion with hyaluronidase, kynurenic acid, and trypsin	DMEM/F12 supplemented with 0.6% glucose, 2 mmol/L glutamine, 3 mmol/L sodium bicarbonate, 5 mmol/L HEPES buffer, 25 mg/mL insulin, 10 mg/mL heparan sulfate, 100 mg/mL transferrin, 20 nmol/L progesterone, 60 mmol/L putrescine, 30 nmol/L selenium chloride, 20 ng/mL EGF, and 20 ng/mL bFGF-2			[41]
	Temporal lobe from 11-wk-old postnatal male Hippocampus, ventricular zone, motor cortex and corpus callosum from and a 27-year-old male	Enzymic digestion with papain, DNase I, and neutral protease	Initially, DMEM/F-12 supplemented with glutamine and 10% FBS After 24 h, DMEM/F12 supplemented with BIT-9500 (bovine serum albumin, transferrin, insulin, 20 ng/mL bFGF, 20 ng/mL EGF, and 20 ng/mL PDGF-AB) and 25% conditioned medium from rat stem cells that produces secretory bFGF and glycosylated form of cystatin C	Fibronectin	More than 70 population doublings in the 11-wk-old postnatal male More than 30 population doublings in the 27-year-old male	[42]
	Temporal lobe	Mechanical dissociation and enzymic digestion with DNase I and trypsin	DMEM/F12 supplemented with 1 mol/L HEPES, 2% B27, 0.1% EGF, and 0.1% bFGF		11 mo	[43]
	Temporal lobe	Enzymic digestion with Papain and DNase I	DMEM/F12 supplemented with bFGF and EGF		3–6 wk	[44,114]
	Lateral ventricular roof	Mechanical dissociation and enzyme digestion with DNase I and trypsin	DMEM/F12 supplemented with bFGF, EGF, and B27		3-7 wk	[45]
	Hippocampus containing hilus, temporal cortex, and subventricular zone including anterior horn and segmented lateral ventricle	Physical mincing and enzyme digestion with trypsin	DMEM/F12 supplemented with N2, 35 μg/mL bovine pituitary extract, 5% fetal calf serum, 40 ng/mL EGF, and 20 ng/mL bFGF		> 60 population doublings	[46]
	Biopsies from filum terminale below conus medullaris	Physical mincing and enzyme digestion with trypsin	DMEM/F12 supplemented with B27, 10 ng/mL LIF, 10 ng/mL bFGF, and 20 ng/mL EGF	Ultra-low attachment dish		[47]

TGFα: Transforming growth factor alpha; DMEM/F12: Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12; FBS: Fetal bovine serum; bFGF: Basic fibroblast growth factor; EGF: Epidermal growth factor.

Table 2 Preclinical results of adult neural stem cells against neurodegenerative diseases

Targeted disease animal model	Cell source	Injection method	Result	Animal species	Ref.
Demyelinated spinal cord injury	Frontal cortex, temporal cortex, hippocampus, and subventricular/subependymal zone of frontal lobe	The midline of the dorsal columns of the spinal cord at three longitudinal sites	The cells elicited extensive remyelination with a peripheral myelin pattern similar to Schwanncell myelination The remyelinated axons conducted impulses at near normal conduction velocities	Rat	[56]
Multiple sclerosis (lysolecithin-demyelinated brain)	Temporal lobe	Local injection to demyelinated brain regions	Transplanted cells migrated to lesions without extending into normal white matter. Implanted progenitors matured as oligodendrocytes, and developed myelin-associated antigens	Rat	[57]
Global brain ischemia	Temporal lobe	The posterior periventricular region above the hippocampus	Adult human NPCs survived, migrated into ischemic regions, and differentiated into functional neural cells No information about therapeutic effects	Rat	[58]
Global brain ischemia	Temporal lobe	Left hippocampus After in vitro differentiation	Injected cells migrated preferentially into an ischemic lesion, which was mediated by SDF-1α and CXCR4 signaling pathways No information about therapeutic effects	Rat	[59]
Focal ischemic stroke	Temporal lobe	Contralateral lateral ventricle	Transplanted cells reduced infarction volumes and enhanced motor activity	Rat	[18]

Table 3 Current clinical trials of neural stem cells against neurodegenerative diseases

Disease	NSC source	Brief title	Trial ID	Condition	Location	Period	Cell source	Route	Phase
ALS	Fetal NSCs	Human neural stem cell transplantation in amyotrophic lateral sclerosis	NCT01640067	Recruiting	Italy	2011-12 -2016-09	Fetal neural stem cells	Spinal cord	I
		Dose escalation and safety study of human spinal cord derived neural stem cell transplantation for the treatment of amyotrophic lateral sclerosis	NCT01730716	Ongoing	United States	2013-05 -2014-09	Spinal cord of a single fetus 8 wk of gestation	Spinal cord after laminectomy	II
		Human spinal cord derived neural stem cell transplantation for the treatment of amyotrophic lateral sclerosis	NCT01348451	Ongoing	United States	2009-01 -2015-12	Spinal cord of a single fetus 8 wk of gestation	Spinal cord after laminectomy	I
Stoke	Adult NSCs	Pilot investigation of stem cells in stroke	NCT01151124	Ongoing	United Kingdom	2010-06 -2015-03	CTX0E03 DP allogeneic neural stem cells	Putamen region of the brain	I
		Pilot Investigation of stem cells in stroke phase II efficacy	NCT02117635	Recruiting	United Kingdom	2014-06 -2015-12	CTX0E03 DP allogeneic neural stem cells	Intracranially via stereotaxic	II
SCI	Adult NSCs	Safety study of human spinal cord-derived neural stem cell transplantation for the treatment of chronic SCI	NCT01772810	Recruiting	United States	2014-08 -2016-02	Human spinal cord-derived neural stem cell	Direct injections into spinal parenchyma	I
		Study of human central nervous system stem cells in patients with thoracic spinal cord Injury	NCT01321333	Ongoing	Canada, Switzerland	2011-03 -2015-05	Human central nervous system stem cells	Thoracic spinal cord	I, II
		Study of human central nervous system stem cell transplantation in cervical spinal cord injury	NCT02163876	Recruiting	United States	2014-10 -2017-05	Human central nervous system stem cells	Cervical spine	II

NSCs: Neural stem cells; ALS: Amyotrophic lateral sclerosis; iPSCs: Induced pluripotent stem cells.