Stem cells out of the bag: characterization of ex vivo expanded mesenchymal stromal cells for possible clinical use

Circular RNAs: typical biomarkers for bone-related diseases

Bone is a connective tissue that has important functions in the human body. Cells and the extracellular matrix (ECM) are key components of bone and are closely related to bone-related diseases. However, the outcomes of conventional treatments for bone-related diseases are not promising, and hence it is necessary to elucidate the exact regulatory mechanisms of bone-related diseases and identify novel biomarkers for diagnosis and therapy. Circular RNAs (circRNAs) are single-stranded RNAs that form closed circular structures without a 5' cap or 3' tail and polycyclic adenylate tails. Due to their high stability, circRNAs have the potential to be typical biomarkers. Accumulating evidence suggests that circRNAs are involved in bone-related diseases, including osteoarthritis, osteoporosis, osteosarcoma, multiple myeloma, intervertebral disc degeneration, and rheumatoid arthritis. Herein, we summarize the recent research progress on the characteristics and functions of circRNAs, and highlight the regulatory mechanism of circRNAs in bone-related diseases.

Current Perspectives on Adult Mesenchymal Stromal Cell-Derived Extracellular Vesicles: Biological Features and Clinical Indications

Extracellular vesicles (EVs) constitute one of the main mechanisms by which cells communicate with the surrounding tissue or at distance. Vesicle secretion is featured by most cell types, and adult mesenchymal stromal cells (MSCs) of different tissue origins have shown the ability to produce them. In recent years, several reports disclosed the molecular composition and suggested clinical indications for EVs derived from adult MSCs. The parental cells were already known for their roles in different disease settings in regulating inflammation, immune modulation, or transdifferentiation to promote cell repopulation. Interestingly, most reports also suggested that part of the properties of parental cells were maintained by isolated EV populations. This review analyzes the recent development in the field of cell-free therapies, focusing on several adult tissues as a source of MSC-derived EVs and the available clinical data from in vivo models.

Adult mesenchymal stem cells and their exosomes: Sources, characteristics, and application in regenerative medicine

Human mesenchymal stem cells (MSCs) have become a hot topic in the development of cell therapies and bioengineering. All kinds of MSCs are genomic stable and have the self-renewal ability. Main sources of MSCs are bone marrow, adipose tissues, umbilical cord and placental tissues. MSCs can be cultured in many undifferentiated passages to grow into more specialized cells, produce secretory factors and also support trophic functions in the body. Exosomes, derived from MSCs also have great potential in regenerative medicine and tissue engineering. Exosomes are secreted by MSCs and have the same therapeutic potential as their parent cells. MSCs and their exosomes combined with biomaterials can also be more effective in promoting the regeneration of tissues and organs. However, for use of MSCs-exosomes as a clinical agent different MSCs-exosomes have been manufactured and their therapeutics effects demonstrated in clinical studies. But there are still many characteristics which are unknown and many barriers still need to be conquered. In this review, we not only highlighted the characteristics of human MSCs and their exosomes, but also provided their latest therapeutic strategies in regenerative medicine.