title: Imaging modalities for the in vivo surveillance of mesenchymal stromal cells.
abstract: Bone marrow stromal cells exist as mesenchymal stromal cells (MSCs) and have the capacity to differentiate into multiple tissue types when subjected to appropriate culture conditions. This property of MSCs creates therapeutic opportunities in regenerative medicine for the treatment of damage to neural, cardiac and musculoskeletal tissues or acute kidney injury. The prerequisite for successful cell therapy is delivery of cells to the target tissue. Assessment of therapeutic outcomes utilize traditional methods to examine cell function of MSC populations involving routine biochemical or histological analysis for cell proliferation, protein synthesis and gene expression. However, these methods do not provide sufficient spatial and temporal information. In vivo surveillance of MSC migration to the site of interest can be performed through a variety of imaging modalities such as the use of radiolabelling, fluc protein expression bioluminescence imaging and paramagnetic nanoparticle magnetic resonance imaging. This review will outline the current methods of in vivo surveillance of exogenously administered MSCs in regenerative medicine while addressing potential technological developments. Furthermore, nanoparticles and microparticles for cellular labelling have shown that migration of MSCs can be spatially and temporally monitored. In vivo surveillance therefore permits time-stratified assessment in animal models without disruption of the target organ. In vivo tracking of MSCs is non-invasive, repeatable and non-toxic. Despite the excitement that nanoparticles for tracking MSCs offer, delivery methods are difficult because of the challenges with imaging three-dimensional systems. The current advances and growth in MSC research, is likely to provide a wealth of evidence overcoming these issues.
authors.affiliation: Department of Renal Transplantation, St Georges Hospital NHS Trust, London, UK.
authors.forename: Mohammad Ayaz
authors.initials: MA
authors.lastname: Hossain
authors.affiliation: Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, UK.
authors.forename: Tina
authors.initials: T
authors.lastname: Chowdhury
authors.affiliation: Department of Renal Transplantation, St Georges Hospital NHS Trust, London, UK.
authors.forename: Atul
authors.initials: A
authors.lastname: Bagul
mesh_terms: D000162:Acoustics; D000818:Animals; D016026:Bone Marrow Transplantation; D002465:Cell Movement; D049109:Cell Proliferation; D058948:Cell Tracking; D003952:Diagnostic Imaging / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry; D015870:Gene Expression; D005786:Gene Expression Regulation; D006801:Humans; D049449:Luminescence; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry; D016377:Organ Transplantation; D010777:Photochemistry; D045663:Quantum Dots; D051381:Rats; D014465:Ultrasonics
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide
keywords: bioluminescence; cellular tracer; in vivo monitoring, magnetic resonance imaging; mesenchymal stromal cell; quantum dots; radioisotope; radiolabelled imaging; ultrasound photoacoustic