Stem cell research is a promising area of transplantation and regenerative medicine with tremendous potential for improving the clinical treatment and diagnostic options across a variety of conditions and enhancing understanding of human development. Over the past few decades, mesenchymal stem cell (MSCs) studies have exponentially increased with a promising outcome. However, regardless of the huge investment and the research attention given to stem cell research, FDA approval for clinical use is still lacking. Amid the challenges confronting stem cell research as a cell-based product, there appears to be evidence of superior effect and heightened potential success in its expressed vesicles, exosomes, as cell-free products. In addition to their highly desirable intrinsic biologically unique structural, compositional, and morphological characteristics, as well as predominant physiochemical stability and biocompatibility properties, exosomes can also be altered to enhance their therapeutic capability or diagnostic imaging potential via physical, chemical, and biological modification approaches. More importantly, the powerful therapeutic potential and superior biological functions of exosomes, particularly, regarding engineered exosomes as cell-free products, and their utilization in a new generation of nanomedicine treatment, vaccination, and diagnosis platforms, brings hope of a change in the near future. This viewpoint discusses the trend of stem cell research and why stem cell-derived exosomes could be the game-changer.
The concept of stem cells emanated in the 19th century as a theoretical postulate that accounted for the ability of certain tissues including, blood and skin to self-renew for the lifetime of an organism. The discovery of stem cells as individually separate and distinct cellular entities followed many years later as a result of developed methods for their prospective isolation, in addition to rigorous bioassays designed to test their potency (
However, irrespective of the huge investment and the attention given to stem cell research, approval for clinical use is still lacking. Amidst the challenges confronted by stem cell research as a cell-based product, there appears to be a gradual paradigm shift from stem cell-based research to its derived exosomes and exosomes from other sources as a cell-free product. After the discovery that exosomes are responsible for the therapeutic effects of MSCs, huge attention has been shifted towards these extracellular vesicles in regenerative medicine in the past few years (
Regardless of the progress made in stem cell research, the only stem cell-based products that are approved for use in the US by the FDA consist of blood-forming stem cells (hematopoietic progenitor cells) derived from cord blood for limited use in patients with disorders that affect the body system that is involved in the production of blood (
More importantly, exosomes, as cell-free therapy, possess enhanced delivery of exogenous biological particles to the target site and directly into the cytosol, circumventing the lysosomal-endosomal pathway, and consequently elevating transfection efficiency (
The constantly expanding exploration of MSC-derived exosomes covers research in several human diseases including application in neurodegenerative conditions and nerve injury (
Stem cell-derived exosome is likely to change the narration of stem cell research, as it presents enormous hope of a breakthrough in therapeutic, diagnostic, prognostic, and vaccination application. However, while stem cells express large quantities of exosomes naturally, effective separation and purification, as well as optimum storage conditions of these vesicles continue to be of concern. There is a need to focus attention on the optimal isolation and purification procedures to allow the production of a well-defined set of pharmaceutical-grade exosome products as a next-generation cell-free therapy in regenerative medicine. Moreover, we still require studies on the best exosome administration route and dosage, as well as a better understanding of the mechanisms and factors that influence their biogenesis and effects.