Table 1.

Preclinical research evaluating MSC EVs as a sepsis therapeutic. All EVs were administered in a phosphate-buffered saline (PBS) vehicle unless otherwise stated.

Ref.	EV source	EV isolation method	EV quantification method for dosing	EV dose, route and time of administration	Model (s)	Sample size (n) (in vivo/in vitro)	Sampling time(s) (in vivo/in vitro)	Beneficial effects	EV mechanisms of action
[145]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	30 μL, jugular vein injection or IT, 0 or 12 h post-injury	E. coli endotoxin-induced ALI in mice, murine Mφ, human AECs	4–32/4	48 h/6, 12, 24 h	- ↓Alveolar WBCs, neutrophils, MIP-2, edema, and BALF protein	KGF mRNA
[146]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	90 μL, IV, 4 h post-injury	E. coli endotoxin-induced ALI in mice, human monocytes, AECs	2–22/5–46	18, 24, 72 h/24, 48 h	- ↑Survival - ↓ Alveolar WBCs, MIP-2, bacterial load - Poly(I:C) pretreatment of MSCs enhanced effects	KGF mRNA
[149]	Human BM MSCs	UC	Resuspended in 2 mL per 7.5e6 cells	Adoptive transfer of Mφ treated with EVs, intranasal, 4 h post injury	LPS-induced ALI in mice, human and murine alveolar Mφ	3–5/3–7	24 h	- ↑ CD206+ human Mφ -↑Mitochondrial respiratory capacity - ↓Neutrophils, TNF-α, protein levels in BALF	Not determined
[54]	Human UMC MSCs	UC	Total protein	30 μg in 150 μL, tail vein injection, 4 h post-injury	CLP in mice, LPS-treated murine BMDMs	5–13/3	48 h/24 h	- EVs from IL-1β pretreated MSCs ↑ M2 polarization of Mφs - ↓TNF-α, iNOS, ↑IL-10 in BMDMs	miR-146a
[147]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	30 μL, IT, simultaneous with injury	LPS-induced ALI in mice, murine Mφ, human LMVECs	3–15/3–4	48 h/3 or 24 h	- ↓ Alveolar WBCs, neutrophils, MIP-2, albumin BALF, lung injury	Ang-1 mRNA
[164]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	60 μL, in culture, simultaneous with injury	Human LMVECs exposed to cytomix (IL-1β, TNF-α, IFN-γ)	3	6, 12, 24 h	- Restored F-actin, ZO-1, VE-cadherin - EV CD44 required for therapeutic effects	Ang-1 mRNA
[148]	Human BM MSCs	AEX column	NTA	5e9 EVs, IV, simultaneous with injury	LPS-induced endotoxemia in mice, murine Mφ	5–7/3	2 h/4 h	-↓iNOS, IL-1β, IL-6, and TNF-α in Mφ -↓IL-6, IL-1β in spleen	Not determined
[150]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	90 μL, IV, 4 h post-injury	E. coli-induced ALI in mice, LPS-treated murine Mφ, and human monocytes	5–13/3–9	12, 24 h/1.5, 4, 14, 24 h	-↑Phagocytosis of monocytes and Mφ - ↑LTB4, ↓ bacterial counts, TNF-α, MIP-2 in BALF -↑LTA4H protein levels	Suppression of MRP1 expression via miR-145
[168]	Human AD MSCs	UC	Total protein	100 μg in 200 μL, tail vein injection, 0.5 h post-injury	LPS-induced ALI in mice, murine BMDMs	7–12/3–8	24, 48 h/24 h	- EVs from young donor (25 years old) ↓ immune cell infiltration, alveolar septal thickness; ↓ Protein, neutrophils, IL-1β, and ↑ 1L-10 in BALF	↓ miR-127-3p and miR-125b-5p in young EVs
[169]	Human BM MSCs	UC	Resuspended in 10 μL per 1e6 source cells	200 or 400 μL, IV, 1 h post-injury	E. coli-induced ALI in ex vivo perfused human lung, LPS-treated human alveolar Mφ	5–11/8	6 h	- ↓Lung hemorrhage, edema, neutrophil infiltration, protein permeability - EVs from poly (I:C) pretreated MSCs ↓bacterial count in BALF	Not determined
[144]	Human UMC MSCs	UC	FACS	1e8 vesicles per kg body weight, tail vein injection, 0.5 h post-injury	E. coli-induced ALI in rats, human Mφ	3–18/3–5	48 h/72 h	- ↑Survival - EVs from IFN-γ pretreated MSCs ↓lung injury, alveolar-arterial oxygen gradient, alveolar protein leak, alveolar TNF-α and ↑eNOS - ↑ Mφ bacteria killing	Not determined
[141]	Human AD MSCs	UC	Total protein	100 μg in 200 μL, tail vein injection, 4 h post-injury	CLP in mice	4–20	24 h, mortality monitored at 0, 6, 12, 24, 36, 48 h	- ↑Survival - ↓Serum Cr, BUN, TNF-α, IL-6, MCP-1 - ↓ Bax, cleaved caspase-3, TNF-α, NF-κB p65, HIF-1α and ↑expression of SIRT1, VEGF, and Bcl-2	Not determined
[109]	Human UMC MSCs	SDG-UC	Total protein	120 μg in 100 μL, tail vein injection, 3 h post-injury	CLP in mice, human renal tubular epithelial cells	6–18/3	24 h, mortality monitored for 3 days	- ↑Survival - ↓Serum Cr, BUN, TNF-α, and IL-1β levels  - ↓Apoptosis, p-IκBα, NF-κB p-P65, TNF-α, 1L-1β, IRAK1 in kidney tissue	miR-146b
[138]	Murine BM MSCs	Exo-quick	Total protein	10 μg in 100 μL, carotid injection immediately following injury	CLP in mice, HUVECs	4–13/3–4	6 h/12 h	- ↓ VCAM/ICAM and immune cells in myocardium - Rescued ejection fraction and fractional shortening	miR-126
[53]	Murine BM MSCs	UC	Total protein	2 μg g−1 body weight in 150 μL of culture medium, tail/jugular vein injection, 1 h post-injury	CLP in mice, LPS-treated murine Mφ and CMs	4–14/3	12 h, mortality monitored for 3 days/12 h	- ↑Survival, ventricular ejection fraction, and cardiac fractional shortening ↓TNF-α, IL-6, IL-1β	miR-223
[165]	Murine BM MSCs	DC	Total protein	100 μg in 200 μL, tail vein injection, immediately prior to injury	LPS-induced ALI in mice, human type 2 AECs	3	24 h/24, 48 h	- Overexpression of miR-30b-3p in EVs ↓apoptosis and ↑ proliferation in AECs - ↓ Alveolar hemorrhage, alveolar septum thickness, pulmonary edema	↓of SAA3 via miR-30b-3p
[143]	Murine AD MSCs	UC	Total protein	100 μg, IV, 3 h post-injury	CLP in rats	6–19	5 Days, mortality monitored daily	- ↑Survival - ↓CD11b/c+, Ly6G+, cells; MIF+ cells; CD4+, CD8+ cells; CD68+ and CD14+ cells, - ↑Treg+ cells	Not determined

Abbreviations: AEC, alveolar epithelial cell; AEX, anion exchange; AD, adipose-derived; ALI, acute lung injury; Ang-1, angiopoietin 1; BALF, bronchoalveolar lavage fluid; BM, bone marrow; Bax, Bcl-2-associated X protein; Bcl-2, B-cell lymphoma-2; BMDM, bone marrow derived macrophages; BUN, blood urea nitrogen; CLP, cecal ligation and puncture; CM, cardiomyocyte; Cr, creatinine; DC, differential centrifugation; EC, endothelial cell; eNOS, endothelial nitric oxide synthase; EV, extracellular vesicle; FACS, fluorescence-activated cell sorting; HIF-1α, hypoxia-inducible factor-1 alpha; LMVEC, lung microvascular endothelial cell; IFN-γ, interferon gamma; IL-1β, interleukin-1 beta; iNOS, inducible nitric oxide synthase; IRAK1, interleukin 1 receptor-associated kinase 1; IT, intratracheal; IV, intravenous; KGF, keratinocyte growth factor; LPS, lipopolysaccharide; LTA₄H, leukotriene A4 hydrolase; LTB₄, leukotriene B4; Ly6G, lymphocyte antigen 6 complex locus G; Mφ, macrophage; MCP-1, monocyte chemoattractant protein-1; MIF, macrophage migration inhibitor factor; MIP-2, macrophage inflammatory protein 2; mRNA, messenger ribonucleic acid; miRNA, micro ribonucleic acid; MRP1, multidrug resistance-associated protein 1; MSC, mesenchymal stem cell; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; NTA, nanoparticle tracking analysis; p-IκBα, phosphorylated inhibitor of nuclear factor kappa B-alpha; Poly (I:C), polyinosinic-polycytidylic acid; SAA3, serum amyloid A3; SDG-UC, sucrose density gradient ultracentrifugation; sirt1, sirtuin 1; TNF-α, tumor necrosis factor-alpha; UC, ultracentrifugation; UMC, umbilical cord; VEGF, vascular endothelial growth factor; VE-cadherin, vascular endothelial cadherin; WBC, white blood cell; ZO-1, zonula occludens-1.