Current challenges for the targeted delivery and molecular imaging of stem cells in animal models

Figures & data

Table 1. Effect of stem cell modifications on in vivo targeted delivery.

Experiment	Modification	Key finding	Citation
Rat BM-MSC transfused into the left ventricular cavity of MI rats	No modification	1% of cells migrate to the infarcted myocardium at 4 h with significant retention in lung	^12
Murine MSC-like cells were injected into the tail vein of 4-mo-old mice	Overexpression of CXCR4 on MSCs through adenovirus infection	∼8 fold increase in retention to bone marrow	^35
Murine MSCs were intramyocardially injected in mice with myocardial infarction	Overexpression of CCR-1 chemokine receptor on MSCs	Increase in MSC survival, migration, and engraftment in ischemic myocardium	^36
Rat MSCs were intravenously infused into tail vain of myocardial infarcted rat	Overexpression of CXCR4 on MSCs	2.5-fold increase engraftment to the infarcted myocardium, leading to reduced LV remodeling and enhanced recovery of function	^37
Human and rat GRPs and MSCs were transplanted into the internal carotid artery of rats	Altering cell size, cell dose, and cell infusion velocity	Stroke at infusion velocity over 1 ml/min, profound decrease in cerebral blood flow for large cells infusion, stroke lesions for dosage injection more than 1 × 10^6	^38
Primary human MSCs were injected into the tail vein of an inflamed model of mice.	Immobilization of SLe^x on MSC surface using prior surface immobilization of biotin and streptavidin	56% efficiency increase in cell localization to the inflamed ear	^20
Human umbilical cord blood cells were injected intravenously into sublethally irradiated immunodeficient (NOD/SCID) mice	Enforced α(1,3)fucosylation and SLe^x expression on CB cells surface	Enhanced selectin binding and bone marrow engraftment of CB cells in irradiated NOD/SCID mice	^18
Human MSCs were intravenously infused into the tail veins of immunodeficient (NOD/SCID) mice	Enforced α(1,3)fucosylation and SLe^x expression on MSCs surface	Robust tethering and rolling interactions and firm adherence of cells on sinusoidal vessels and rapid infiltration to the marrow parenchyma	^14
Murine MSCs were injected into the mice with inflammatory bowel disease	Coating MSCs with VCAM-1 antibody using protein G	Highest delivery efficiency to inflamed mesenteric lymph node	^39
Lin- Sca+ murine stem cells were intravenously injected into mice with infarcts created by ligation of LAD	Cells modified with bispecific antibodies against murine stem cell c-kit and VCAM-1 up-regulated on injured myocardial cells	Increased retention to injured myocardium	^40
Human HSC intravenously injected into the xenogeneic rat model with ischemic injury induced by transient ligation LAD	Decorating HSCs with Bispecific antibodies that binds human CD45 and myosin light chain, an organ-specific injury antigen expressed by infarcted myocardium	Enhanced cell homing to myocardial infarcted tissue	^41
Human MSCs intra-ventricularly injected through the left ventricle of mice with myocardial infarction	Coating MSCs with palmitated derivatives of phage-peptides (CRPPR, CRKDKC, KSTRKS, and CARSKNKDC)	Increased binding to infarcted regions	^42
Swine CDC and MSC intracoronary infused into the brief cardiac IR injury swine model	Coupling CDCs and MSCs with 19Fc[FUT7+] plus FUT7 over-expression in the cells	28% of cells localized in LAD proximal to IR site	^7

Abbreviations: BM-MSC: Bone Marrow-derived Mesenchymal Stem cells; MI: Myocardial Infarction; MSC: Mesenchymal stem cells; LV: Left ventricle; GRP: Glial restricted precursors; NOD/SCID: Nonobese diabetic/ sever combined immunodeficient; VCAM: vascular cell adhesion molecule; AD: Left anterior descending; HSC: haematopoietic stem cells; CDC: Cardiosphere derived cells; IR: Ischemia reperfusion.

Figure 1. Complementary glycoengineering methods to enhance stem cell delivery. Coupling the recombinant PSGL-1 protein (19Fc[FUT7+]) to stem cell surface enhances cell binding to P-selectin. Overexpression of the α(1,3)fucosyltransferase FUT7, on the other hand, enhances cell binding to E-selectin. CDCs functionalized with both modifications were retained in the pig heart in a brief ischemia-reperfusion model (ref.⁷).

Table 2. Comparison of cell prelabeling versus reporter gene for all major imaging modalities.

Label	Modality	Cell sensitivity (Small animal)	Cell sensitivity (Large animal)	Advantages	Disadvantages
Prelabeling
Near Infrared dye	IVM, FMT	1 × 10^0 ^31	n/a	high sensitivity(10^-17M) high spatial resolution (<1 µm) (IVM) inexpensive multiplex capability improved depth penetration (FMT)	low depth penetration (IVM) limited clinical use invasive procedure (IVM) loss of signal with depth
Indium oxine	SPECT	6 × 10^5 ^43	1 × 10^7 44	high sensitivity (10^-11M) ease of use multiplex capability	label dilution radioactive dose signal decay planar (not tomographic) low spatial resolution (2–10mm)
FDG	PET	5 × 10^4 28	3 × 10^7 45	high sensitivity (10^-12M) tomographic natural molecule labeling quantitative	label dilution radioactive dose signal decay cyclotron required expensive low spatial resolution (2–10mm)
SPIO NP	MRI	2 × 10^2 ^46	1.5 × 10^7 10	high spatial resolution improved sensitivity no radioactivity	label dilution toxicity low sensitivity (10^-12M, MR) highly sequence dependent many imaging artifacts negative contrast method semiquantitative
Reporter Genes
GFP	IVM	1 × 10^0 ^31	n/a	high sensitivity (10^-17M) high spatial resolution (<1 µm) inexpensive multiplex capability serial imaging	low depth penetration limited clinical use invasive procedure loss of signal with depth
Firefly Luciferase	BLI	1 × 10^3 9	n/a	high sensitivity (10^-17M) inexpensive multiplex capability (Rluc) serial imaging	low spatial resolution loss of signal with depth low light cooled CCD required
HSV1TK/SR39TK 18F-FHBG	PET	1 × 10^7 47	2.5 × 10^8 10	high sensitivity (10^-12M) tomographic serial imaging clinically approved	radioactive dose signal decay cyclotron required expensive

Abbreviations: IVM: intravital microsopy; FMT: fluorescence molecular tomography; SPECT Single photon CT; PET: Positron emission tomography; MRI: Magnetic resonance imaging; BLI: Bioluminescence; SPIO: Superparamagnetic Iron Oxide Particles; NP: nanoparticles; HSV1-TK: Herpes Simplex Virus Type I truncated thymidine kinase; SR39TK: Mutant Herpes Simplex Virus Type I truncated mutated thymidine kinase; 18F-FHBG: 18F-radiolabelled 9-[4-fluoro-3-(hydroxyl methyl) butyl] guanine

Barbash IM, Chouraqui P, Baron J, Feinberg MS, Etzion S, Tessone A, Miller L, Guetta E, Zipori D, Kedes LH. Systemic delivery of bone marrow–derived mesenchymal stem cells to the infarcted myocardium feasibility, cell migration, and body distribution. Circulation 2003; 108(7):863-868; PMID:12900340; https://doi.org/10.1161/01.CIR.0000084828.50310.6A

 PubMed Web of Science ®Google Scholar

Lien CY, Chih‐Yuan Ho K, Lee OK, Blunn GW, .Su Y. Restoration of Bone Mass and Strength in Glucocorticoid‐Treated Mice by Systemic Transplantation of CXCR4 and Cbfa‐1 Co‐Expressing Mesenchymal Stem Cells. J Bone Miner Res 2009; 24(5):837-48; PMID:19113920; https://doi.org/10.1359/jbmr.081257

 PubMed Web of Science ®Google Scholar

Cheng Z, Ou L, Zhou X, Li F, Jia X, Zhang Y, Liu X, Li Y, Ward CA, Melo LG. Targeted migration of mesenchymal stem cells modified with CXCR4 gene to infarcted myocardium improves cardiac performance. Mol Ther 2008; 16(3):571-9; https://doi.org/10.1038/sj.mt.6300374

 PubMed Web of Science ®Google Scholar

Janowski M, Lyczek A, Engels C, Xu J, Lukomska B, Bulte JW, Walczak P. Cell size and velocity of injection are major determinants of the safety of intracarotid stem cell transplantation. J Cereb Blood Flow Metab 2013; 33(6):921-7; PMID:23486296

 PubMed Web of Science ®Google Scholar

Sarkar D, Spencer JA, Phillips JA, Zhao W, Schafer S, Spelke DP, Mortensen LJ, Ruiz JP, Vemula PK, Sridharan R, et al. Engineered cell homing. Blood 2011; 118(25):e184-91; https://doi.org/10.1182/blood-2010-10-311464

 PubMed Web of Science ®Google Scholar

Xia L, McDaniel JM, Yago T, Doeden A, McEver RP. Surface fucosylation of human cord blood cells augments binding to P-selectin and E-selectin and enhances engraftment in bone marrow. Blood 2004; 104(10):3091-6; https://doi.org/10.1182/blood-2004-02-0650

 PubMed Web of Science ®Google Scholar

Sackstein R, Merzaban JS, Cain DW, Dagia NM, Spencer JA, Lin CP, Wohlgemuth R. Ex vivo glycan engineering of CD44 programs human multipotent mesenchymal stromal cell trafficking to bone. Nat Med 2008; 14(2):181-7; PMID:18193058; https://doi.org/10.1038/nm1703

 PubMed Web of Science ®Google Scholar

Ko IK, Kim BG, Awadallah A, Mikulan J, Lin P, Letterio JJ, Dennis JE. Targeting improves MSC treatment of inflammatory bowel disease. Mol Ther 2010; 18(7):1365-72; https://doi.org/10.1038/mt.2010.54

 PubMed Web of Science ®Google Scholar

Lum LG, Fok H, Sievers R, Abedi M, Quesenberry PJ, Lee RJ. Targeting of Lin− Sca+ hematopoietic stem cells with bispecific antibodies to injured myocardium. Blood Cells Mol Dis 2004; 32(1):82-7; PMID:14757418

 PubMed Web of Science ®Google Scholar

Lee RJ, Fang Q, Davol PA, Gu Y, Sievers RE, Grabert RC, Gall JM, Tsang E, Yee MS, Fok H. Antibody targeting of stem cells to infarcted myocardium. Stem Cells 2007; 25(3):712-7; PMID:17138964; https://doi.org/10.1634/stemcells.2005-0602

 PubMed Web of Science ®Google Scholar

Kean TJ, Duesler L, Young RG, Dadabayev A, Olenyik A, Penn M, Wagner J, Fink DJ, Caplan AI, Dennis JE. Development of a peptide-targeted, myocardial ischemia-homing, mesenchymal stem cell. J Drug Target 2012; 20(1):23-32; PMID:22047107; https://doi.org/10.3109/1061186X.2011.622398

 PubMed Web of Science ®Google Scholar

Mondal N, Buffone A, Jr, Stolfa G, Antonopoulos A, Lau JT, Haslam SM, Dell A, Neelamegham S. ST3Gal-4 is the primary sialyltransferase regulating the synthesis of E-, P-, and L-selectin ligands on human myeloid leukocytes. Blood 2015; 125(4):687-96; PMID:25814486; https://doi.org/10.1182/blood-2014-07-588590

 PubMed Web of Science ®Google Scholar

Lo CY, Weil BR, Palka BA, Momeni A, CantyJr, JM, Neelamegham S. Cell surface glycoengineering improves selectin-mediated adhesion of mesenchymal stem cells (MSCs) and cardiosphere-derived cells (CDCs): Pilot validation in porcine ischemia-reperfusion model. Biomaterials 2016; 74:19-30; PMID:26433489; https://doi.org/10.1016/j.biomaterials.2015.09.026

 PubMed Web of Science ®Google Scholar