molecular composition [54]. Proteomic analysis revealed that mesenchymal stem
cells secreted at least 3 types of EVs, which suggested that cells secreted many
types of EVs in terms of their molecular composition. This implies the mechanistic
understanding of biodistribution more complex and difficult. The composition of
EVs secreted by a cell can be changed by cellular condition at one time and, even
more, EVs secreted at one time from a single cell have subpopulation groups.
8.2.5 Future Direction for Biodistribution Analysis and Its
Application
Various factors affect biodistribution results of EVs. It resulted in variable
biodistribution results between different studies: some reported exaggerated tissue
homing effects and others emphasized on mononuclear phagocyte system
(RES) uptake only. Nonetheless, the important fact is that there are various types of
EVs. The broad spectrum of EVs have different physiologic characters. In vivo
distribution of EVs may be changed according to all the different in vivo conditions
of each living subject as well. Because of this complexity, simultaneous tracking of
EVs during usage of therapeutic purposes is required as a future work. Standardized
procedures for the isolation and purification of EVs and multimodal labeling process will be needed as well.
Imaging of EVs is essential to understand the biodistribution of EVs. It also
allows direct monitoring of EVs whether they targeted the specific tissue when we
used EVs for therapeutic purposes. However, each imaging method has limitations
in terms of feasibility of clinical application, capability of quantitation and easy
availability. That is why we should concentrate on multimodal imaging of EVs. As
EVs have various biomolecules in their surface and we can load drugs and biologic
or nano therapeutics into them, EVs could work as a multifunctional endogenous
nano-platform. Various feasible tailoring methods including surface modification,
reporter system and loading therapeutic radionuclides could facilitate clinical
application of EVs.
References
1. A.V. Vlassov, S. Magdaleno, R. Setterquist, R. Conrad, Exosomes: current knowledge of
their composition, biological functions, and diagnostic and therapeutic potentials. Biochim.
Biophys. Acta 1820(7), 940–948 (2012)
2. Y. Lee, S. El Andaloussi, M.J. Wood, Exosomes and microvesicles: extracellular vesicles for
genetic information transfer and gene therapy. Hum. Mol. Genet. 21(R1), R125–R134 (2012)
3. Y. Sun, J. Liu, Potential of cancer cell-derived exosomes in clinical application: a review of
recent research advances. Clin. Ther. 36(6), 863–872 (2014)
162
H. Choi and D. S. Lee
cells secreted at least 3 types of EVs, which suggested that cells secreted many
types of EVs in terms of their molecular composition. This implies the mechanistic
understanding of biodistribution more complex and difficult. The composition of
EVs secreted by a cell can be changed by cellular condition at one time and, even
more, EVs secreted at one time from a single cell have subpopulation groups.
8.2.5 Future Direction for Biodistribution Analysis and Its
Application
Various factors affect biodistribution results of EVs. It resulted in variable
biodistribution results between different studies: some reported exaggerated tissue
homing effects and others emphasized on mononuclear phagocyte system
(RES) uptake only. Nonetheless, the important fact is that there are various types of
EVs. The broad spectrum of EVs have different physiologic characters. In vivo
distribution of EVs may be changed according to all the different in vivo conditions
of each living subject as well. Because of this complexity, simultaneous tracking of
EVs during usage of therapeutic purposes is required as a future work. Standardized
procedures for the isolation and purification of EVs and multimodal labeling process will be needed as well.
Imaging of EVs is essential to understand the biodistribution of EVs. It also
allows direct monitoring of EVs whether they targeted the specific tissue when we
used EVs for therapeutic purposes. However, each imaging method has limitations
in terms of feasibility of clinical application, capability of quantitation and easy
availability. That is why we should concentrate on multimodal imaging of EVs. As
EVs have various biomolecules in their surface and we can load drugs and biologic
or nano therapeutics into them, EVs could work as a multifunctional endogenous
nano-platform. Various feasible tailoring methods including surface modification,
reporter system and loading therapeutic radionuclides could facilitate clinical
application of EVs.
References
1. A.V. Vlassov, S. Magdaleno, R. Setterquist, R. Conrad, Exosomes: current knowledge of
their composition, biological functions, and diagnostic and therapeutic potentials. Biochim.
Biophys. Acta 1820(7), 940–948 (2012)
2. Y. Lee, S. El Andaloussi, M.J. Wood, Exosomes and microvesicles: extracellular vesicles for
genetic information transfer and gene therapy. Hum. Mol. Genet. 21(R1), R125–R134 (2012)
3. Y. Sun, J. Liu, Potential of cancer cell-derived exosomes in clinical application: a review of
recent research advances. Clin. Ther. 36(6), 863–872 (2014)
162
H. Choi and D. S. Lee