Modulating poststroke inflammatory mechanisms: Novel aspects of mesenchymal stem cells, extracellular vesicles and microglia

Table 1 Therapeutic application of mesenchymal stem cell-derived extracellular vesicles in preclinical disease models associated with cerebral ischemia

Ref.	Country	Species	Ischemia model	Cell source	Key outcomes
Geng et al[84], 2019	China	Rats	MCAO	Adipose	Improve tissue recovery, neurogenesis, angiogenesis; Reduce Inflammation
Xin et al[93], 2013	America	Rats	MCAO	Adipose	Improve brain recovery, angiogenesis; Reduce infarct volume, inflammation
Chen et al[82], 2016	Taiwan	Rats	MCAO	BM	Improve tissue recovery, neurogenesis, angiogenesis, neuronal plasticity
Tian et al[91], 2018	China	Mice	MCAO	BM	Inhibit inflammatory response and apoptosis
Xin et al[92], 2017	America	Rats	MCAO	BM	Improve tissue recovery, neurogenesis, neuronal and neurite plasticity
Jiang et al[85], 2018	China	Rats	MCAO	Adipose	Reduce infarct volume and inflammation
Yang et al[94], 2018	China	Mice	Photothrombosis	BM	Promote angiogenesis
Zhang et al[95], 2019	China	Mice	MCAO	BM	Promote angiogenesis
Liu et al[87], 2019	China	Rat	MCAO	BM	Improved brain neuron density and neurological score
Deng et al[83], 2019	China	Mice	MCAO	BM	Reduce infarct volume and inflammation
Nalamolu et al[88], 2019	America	Rats	MCAO	UC	Improve brain recovery; Reduce infarct volume
Nalamolu et al[89], 2019	America	Rats	MCAO	UC	Improve brain recovery; Reduce infarct volume
Li et al[86], 2020	China	Mice	MCAO	UC	Reduce infarct volume; Inhibit inflammatory response and apoptosis
Zhao et al[20], 2020	China	Rats	MCAO	BM	Reduce infarct volume and inflammation; Improve neurological deficits
Zhao et al[21], 2020	China	Rats	MCAO	BM	Improve motor, learning and memory abilities; Reduce inflammation
Safakheil and Safakheil[90], 2020	Iran	Rats	MCAO	BM	Improve functional recovery; Reduce infarct volume and inflammation
Otero-Ortega et al[100], 2020	Spain	Rats	Endothelin-1	Adipose	Improve functional recovery and cells proliferation, Reduce infarct volume
Otero-Ortega et al[103], 2017	Spain	Rats	Endothelin-1	Adipose	Improve functional recovery and neurogenesis, Reduce infarct volume
Moon et al[101], 2019	South Korea	Rats	MCAO	Cord blood	Promote angiogenesis and neurogenesis
Doeppner et al[80], 2015	Germany	Mice	MCAO	BM	Improve tissue recovery, neurogenesis, and angiogenesis
Dabrowska et al[99], 2019	Poland	Rats	Ouabain	BM	Reduce inflammation
Haupt et al[98], 2021	Germany	Mice	MCAO	BM	Increased neurological recovery and neurogenesis
Xia et al[97], 2020	China	Rats	MCAO	BM	Reduce infarct volume neurological deficits, Enhance angiogenesis
Wang et al[102], 2020	Germany	Mice	Stroke	BM	Immunosuppression and neuroprotection
Kuang et al[96], 2020	Germany	Mice	MCAO	Adipose	Reduced neuronal death and infarct size, Increased neurological recovery

BM: Bone Marrow; UC: Umbilical cord; MCAO: Middle cerebral artery occlusion; MSCs: Mesenchymal stem cells.

Table 2 Preclinical stroke studies assessing the effect of mesenchymal stem cells and mesenchymal stem cell-derived extracellular vesicles on the activation of microglia

Ref.	Country	Species	Cell type	Dosage	Route	Cell	Delivery	Microglia	Microglia	Signal	Ischemic
						Source	Timing	Marker	Activation	Pathway	Model
Cunningham et al[109], 2020	United Kingdom	Mice	MSCs	1.4 × 106	Sub	BM	1 h and 24 h	Iba1	No effect	IL-1α	MCAO
Narantuya et al[115], 2010	Japan	Rats	MSCs	NA	IV	BM	NA	ED1/Iba1	Inhibit	NA	BCAO
Ishizaka et al[111], 2013	Japan	Rats	MSCs	1 × 106	IA	NA	1, 4 or 7 d	ED1	Inhibit	NA	MCAO
Yamaguchi et al[120], 2018	Japan	Rats	MSCs	1 × 106	IA	Blood	24 h	Iba1	Inhibit	NA	MCAO
Wang et al[119], 2014	China	Rats	MSCs	2 × 106	IV	BM	3 h	CD45/CD11b	Inhibit	NA	dMCAO
Wei et al[19], 2012	America	Rats	MSCs	1 × 106	IV	BM	24 h	Iba1/OX-42	Inhibit	NA	MCAO
Nakajima et al[114], 2017	Japan	Rats	MSCs	1 × 106	IV	BM	0 or 3 h	Iba1/TNF-α/IL6/IL-1β	Inhibit	IL-10	MCAO
McGuckin et al[113], 2013	France	Rats	MSCs	NA	Stereotaxis	UC	NA	ED1/Iba1	Inhibit	CD200/STAT3	Ouabain injection
Li et al[112], 2018	China	Rats	MSCs	1 × 106	IV	BM	1 h	CD68/Iba1	Inhibit	IGF-1/BDNF	dMCAO
Lv et al[108], 2016	China	Cells	MSCs	NA	NA	BM	NA	TNF-α/IL6/IL-1β	Inhibit	TNF-α/MSCs/GDNF	OGD
Wang et al[102], 2020	Germany	Mice	EVs	2 × 106	IV	BM	Immediately	CD45/CD11b	Inhibit	NA	MCAO
Dabrowska et al[99], 2019	Poland	Rats	EVs	5 × 105	IA	BM	48 h	ED1	Inhibit	NA	Ouabain injection
Geng et al[84], 2019	China	Rats	EVs	NA	NA	Adipose	NA	Iba1, TNF-α, IL-1β	Inhibit	miRNA-126	MCAO
Liu et al[87], 2019	China	Rats	EVs	5 × 105	IV	BM	2 h	Iba1	Inhibit	NA	MCAO
Tian et al[91], 2018	China	Mice	EVs	NA	IV	BM	12 h	Iba1	Inhibit	NA	MCAO
Sheikh et al[117], 2019	Japan	Rats	MSCs	3 × 106	IV	BM	24 h	ED1/Iba1	Inhibit	IL-1β/HIF-1α and VEGF	MCAO
Wang et al[118], 2013	Japan	Rats	MSCs	3 × 106	IV	BM	24 h	ED1/Iba1/IL-1β/TNF-α/iNOS, MCP-1	Inhibit	TLR2/CD40/NF-kB	MCAO
Yoo et al[122], 2013	South Korea	Rats	MSCs	5 × 105	Stereotaxis	BM	3 days	CD68/Iba1/MCP-1; TNF-α/iNOS/IL-1β	Inhibit	TGF-β1/MCP-1	MCAO
Sheikh et al[116], 2011	Japan	Rats	MSCs	3 × 106	IV	BM	24 h	Iba1/iNOS/Cox-2/IL8/MCP-1	Inhibit	IL5 and Fractalkine	MCAO
Feng et al[110], 2020	China	Mice	MSCs	1 × 106/20 g	IV	UC	2 weeks	M1: CD16/32, Iba1; M2: CD206	Polarization	H3 methylation	LPS
Yang et al[121], 2020	China	Rats	MSCs	1 × 106	IV	BM	24 h before	M1: iNOS/Iba1; M2: Arg 1	Polarization	miR-30a*	MCAO
Jiang et al[85], 2018	China	Rats	EVs	NA	IV	Adipose	NA	M1: TNF-α/IL-6/iNOS; M2: IL-4/CD206/IL-10	Polarization	miR-30d-5p	MCAO
Li et al[86], 2020	China	Mice	EVs	NA	IV	UC	NA	M1: iNOS/CD38/ IL-6/TNF-α/CCL-2; M2: Arg 1/CD206	Polarization	miR-26b-5p	MCAO
Zhao et al[20], 2020	China	Rats	EVs	200 μL	IV	BM	1 or 14 d	M1: CD16-32/IL-6/IL-1β; M2: CD206/ IL-10	Polarization	miR-223-3p/ CysLT2R	MCAO
Zhao et al[21], 2020	China	Rats	EVs	200 μL	IV	BM	2 h	M1: CD86 NOS/IL-12/TNF-α; M2: CD206 /TGF-β/BDNF	Polarization	CysLT2R and ERK1/2	MCAO

NA: Not available; IA: Intraarterial; IV: Intravenous; Sub: Subcutaneous; BM: Bone marrow; UC: Umbilical cord; OGD: Oxygen-glucose deprivation; HIF-1α: Hypoxia inducible factor-1α; dMCAO: Distal middle cerebral artery occlusion; MSCs: Mesenchymal stem cell; EVs: Extracellular vehicles; LPS: Lipopolysaccharide; BCAO: Bilateral carotid artery occlusion; c(RGDyK): Cyclo (Arg-Gly-Asp-D-Tyr-Lys); MCP-1: Monocyte chemoattractant protein-1; iNOS: Inducible nitric oxide; IL: Interleukin; NF-κB: Nuclear factor-κB; TLR: Toll-like receptor; VEGF: Vascular endothelial growth factor; TGF: Transforming growth factor; IGF: Insulin-like growth factor; BDNF: Brain-derived neurotrophic factor; TNF: Tumor necrosis factor; GDNF: Glial-derived neurotrophic factor; COX-2: Cyclooxygenase-2; CysLT2R: Cysteinyl leukotrienes receptor; ERK: Extracellular regulated protein kinase.

Table 3 The key parameter of clinical trials using transplantation of mesenchymal stem cells in treating ischemic stroke

Ref.	Country	Design	Type	Route	MSCs source	Sample size (cases)		Dose	How long	Follow-up
					Auto or allo	MSCs	Control	(Mean)	(Mean)	(Mean)
Savitz et al[137], 2011	America	Non-RCT	Acute	IV	BM/Auto	10	NA	100 × 106	1-3 d	0.5 yr
Lee et al[138], 2010	South Korea	RCT	Acute	IV	PIC/Auto	16	36	50 × 106	1 wk	5 yr
Bhasin et al[151], 2011	India	Non-RCT	Chronic	IV	BM/Auto	4	5	50-60 × 106	8 wk	24 wk
Bhasin et al[139], 2012	India	Non-RCT	Chronic	IV	PIC/Auto	12	12	50-60 × 106	3-24 mo	0.5 yr
Bhasin et al[140], 2016	India	Non-RCT	Chronic	IV	PIC/Auto	20	20	50-60 × 106	3-24 mo	0.5 yr
Chen et al[141], 2014	China	RCT	Chronic	Stereotactic	PB/Auto	15	15	3-8 × 106	0.5-5 yr	1 yr
Jiang et al[149], 2013	China	Non-RCT	NA	Catheterization	UC/Allo	3	NA	20 × 106	11-22 d	0.5 yr
Laskowitz et al[14], 2018	America	RCT	Acute	IV	UC/Allo	10	10	3.34 × 106	3-9 d	1 yr
Levy et al[142], 2019	America	Non-RCT	Chronic	IV	NA/Allo	15 and 20	NA	NA	NA	1 yr
Moniche et al[143], 2012	Spain	RCT	Subacute	IA	PIC/Auto	10	10	159 × 106	5-9 d	0.5 yr
Prasad et al[144], 2014	India	RCT	Subacute	IV	PIC/Auto	60	60	280.5 × 106	1-4 mo	0.5 yr
Suárez-Monteagudo et al[150], 2009	Cuba	Non-RCT	NA	IV	BM/Auto	3	NA	NA	NA	3 M
Vahidy et al[145], 2019	America	RCT	Acute	IV	BM/Auto	25	30	NA	1-3 d	2 yr
Zhang et al[146], 2019	China	Non-RCT	NA	Stereotactic	FSC/Allo	9	NA	NA	494 d	2 yr
Díez-Tejedor et al[148], 2014	Spain	RCT	Acute	IV	Adipose/Allo	20	20	NA	0.5 mo	2 yr
Feng et al[147], 2014	China	NA	Subacute	Stereotactic	UC/Allo	50	50	100 × 106	0.5-1 mo	0.25 yr
Jaillard et al[153], 2020	France	RCT	Subacute	IV	BM/Allo	16	15	100-300 × 106	3 wk	24 mo
De Keyser[152], 2005	South Korea	Non-RCT	Acute	IV	BM/Allo	5	25	50 × 106	4-9 wk	12 mo

NA: Not available; MSCs: Mesenchymal stem cells; Auto: Autologous; Allo: Allogenicr; PIC: Posterior iliac crest; IV: Intravenous; IA: Intraarterial; RCT: Randomized controlled trial; UC: Umbilical cord; BM: Bone marrow; FSC: Fetal spinal cord; PB: Peripheral blood.