Current Stem Cell Research & Therapy - Volume 12, Issue 7, 2017

Background: The primary roles of mesenchymal stem cells (MSCs) are to maintain the stem cell niche, facilitate recovery after injury, and ensure healthy aging and the homeostasis of organ and tissues. MSCs have recently emerged as a new therapeutic option for hair loss. Objective: Since adipose-derived stem cells (ADSCs) are the most accessible sources of MSCs, ADSCbased hair regeneration is investigated. Besides replacing degenerated cells in affected organs, ADSCs exhibit their beneficial effects through the paracrine actions of various cytokines and growth factors. Results: Several laboratory experiments and animal studies have shown that ADSC-related proteins can stimulate hair growth. In addition, we introduce our clinical pilot studies using conditioned media of ADSCs for pattern hair loss in men and women. Conclusion: We believe that conditioned media of ADSCs represents a promising alternative therapeutic strategy for hair loss. We also discuss practical therapeutic challenges and the direction of future research.

Background: Adipose-derived stem cells secrete various cytokines that promote hair growth. Objective: To describe our experience of hair regeneration therapy using adipose-derived stem cellconditioned medium. Results: We performed the hair regeneration therapy in numerous Japanese patients and reported good results. We described characteristics of the commercialized conditioned medium, treatment methods, and future directions. Conclusion: Treatment using adipose-derived stem cell-conditioned medium is highly effective and may represent a new therapy for alopecia.

Background: Adipose-derived stem cells (ADSCs) are mesenchymal stem cells (MSCs) within the stromal vascular fraction of subcutaneous adipose tissue. ADSCs secrete growth factors and other proteins, and have been used to regenerate skin with satisfactory results. Objective: This review focuses on the effect of ADSCs and their secretory factors on the stimulation of hair growth in vitro, ex vivo and in vivo. Results: The conditioned media of ADSCs (ADSC-CM) increases the proliferation rate of human follicular cells. ADSCs-derived proteins improve hair growth and protect human dermal papilla cells against cytotoxic injury caused by androgen and reactive oxygen species. Moreover, ADSC-CM induces the anagen phase and promotes hair growth in mice, and enhances the elongation of hair shafts in ex vivo human hair organ cultures. Conclusion: ADSC-CM promotes hair growth in vitro, ex vivo, and in vivo. Given that ADSCs are one of the most accessible sources of MSCs, ADSC-derived proteins may be feasible clinical therapeutic agents for the treatment of hair loss.

Background: Spermatogonial stem cells (SSCs) are unique in mammals because they can transmit genetic information from generation to generation and it is of significant importance. In testes, Sertoli cells, peritubular myoid cells, Leydig cells and other interstitial cells contribute to the spermatogonial stem cell “niche”. So, creation of niche in an in vitro condition that mimics the in vivo environment is essential to maintain functional characteristic of SSCs. Objective: In this review, we describe the impact of nanofiber scaffolds on the culture of SSCs derived from human-to-mouse. Results: Nanofiber Matrices mimic the architecture and size scale of the natural extracellular matrix (ECM). The scaffold provides more three-dimensional (3D), biomimicking and topographical signals to the cells and results in a more physiologically relevant cellular phenotype. Several investigators use different nanofiber scaffold-like carbon nanotubes (CNTs) scaffold, poly-L-lactic acid (PLLA) nanofiber scaffold, 3D soft agar culture system, human serum albumin (HSA)/tri calcium phosphate nanoparticles (TCPNPs) and electrospun polyamide nanofiber for proliferation and maintenance of self-renewal activity of the SSCs. Conclusion: Application of nanofiber scaffolds for in vitro culture of the SSCs may produce spermatogonial stem cells that can be used in regenerative medicine, tissue engineering, assisted reproductive technology and in the treatment of infertility in pre-pubertal cancer patients.

Background: Liver failure is a devastating clinical syndrome with a persistently mortality rate despite advanced care. Orthotopic liver transplantation protected patients from hepatic failure. Yet, limitations including postoperative complications, high costs, and shortages of donor organs defect its application. The development of stem cell therapy complements the deficiencies of liver transplantation, due to the inherent ability of stem cells to proliferate and differentiate. Objective: Understand the source of stem cells, as well as the advantages and disadvantages of stem cell therapy. Method: Based on published papers, we discussed the cell sources and therapeutic effect of stem cells. We also summarized the pros and cons, as well as optimization of stem cell-based treatment. Finally outlook future prospects of stem cell therapy. Results and Conclusion: Stem cells may be harvested from a variety of human tissues, and then used to promote the convalescence of hepatocellular function. The emergence of the co-cultured system, tissueengineered technology and genetic modfication has further enhanced the functionality of stem cells. However, the tumorigenicity, the low survival rate and the scarcity of long-term treatment effect are obstacles for the further development of stem cell therapy. In this review, we highlight current research findings and present the future prospects in the area of stem cell-based treatment for liver failure.

Background: Traditional attempts to grow bone grafts in vitro have been based on culturing cell-scaffold constructs under static culture conditions. However, limitations associated with this approach have led to the development of various types of technologies and equipments. One of these is a bioreactor acting as an intermediate between static (in vitro) and dynamic (in vivo) conditions, which can mimic physiological and mechanical body conditions. Objective: The aim of this study was to systematically review the available literature on application of different types of bioreactors in bone tissue engineering. Methods: A thorough search in PubMed and Google Scholar databases from January 2011 to December 2016 was performed. All in vitro and in vivo studies about bioreactor applications in bone tissue engineering were included and categorized according to bioreactor types. Conclusion: A comprehensive systematic review of all the studies from the past five years yielded several findings: (1) combined bioreactors seem effective in bone tissue engineering; (2) 1- 2 ml/min is an appropriate flow rate range; (3) a cylinder is an appropriative scaffold shape; and (4) incubation of the scaffold with cells prior to transfer to the bioreactor followed by administration of osteogenic medium in the bioreactor seems an efficient approach to help cells properly attach and differentiate.