TITLE:
Advances in Regenerative Medicine: From Stem Cells to Organoids
AUTHORS:
Jeanne Adiwinata Pawitan
KEYWORDS:
Regenerative Medicine, Stem Cell, RCT, Secretomes, Metabolites, Organoid, Scaffold
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.6 No.12,
December
31,
2018
ABSTRACT: Stem cells have moved from lab to bedside, and many initial studies showed promising results. Therefore big companies are entering the business. However, most initial studies did not used controls to make sure of the efficacy of stem cells. Many phase-1 studies showed safety of stem cell therapies, when precaution measures were adapted. However, efficacy needs to be proven by randomized controlled trials (RCT) to exclude placebo effects. Recently, various RCTs for various conditions have been done with various contradictory results. Therefore, a meta-analysis is very useful to know whether a stem cell therapy really work for a certain condition. As various centres used various type of stem cells, various dose, and route of application, as well as different outcome measures with various results for one certain condition, sometimes it is difficult to conduct a meta-analysis when there is high heterogeneity, which is like pooling “apples” with “oranges” and “avocado” that will lead to a misleading conclusion. In many cases, where the studies are highly heterogeneous, and the heterogeneity can’t be identified, then a descriptive systematic review is the best solution to take a conclusion which protocol is the best and valuable to be standardized. Formerly it was believed that stem cells that are given to patients work by differentiating into the needed cells, and thus replacing damaged cell. However, recent evidence showed that only a few stem cells homed to the desired area, while a large amount went to various areas that were remote from the damaged area. Even though they were trapped in remote areas, the stem cells still exerted beneficial effects by remote signalling and secretion of various beneficial factors. Therefore, there are attempts to produce stem cell secretomes/metabolites to replace the stem cells, as metabolites are easier to handle and transported compared to the cells themselves. In addition, various studies worked on substitute tissue/organs “ex vivo” to be transplanted to replace a damaged organ. There are various means to produce a tissue/an organ/organoid “ex vivo” (tissue engineering) by using various stem cells, scaffold, and soluble factors, in various vessels from static vessel to bioreactors, and “on chips”. Though these attempts are in the initial stage, but some translational animal studies have been done. A more usual use of these “ex vivo” developed tissues/organs/organoids is for drug testing, such as toxicity testing, and for studying the mechanism of certain diseases that is directed toward the development of a cure of the diseases. In conclusion, many stem cell therapies have entered RCTs, but no standardized and approved protocol has been established, while organoids are usually used for drug testing and studying the mechanism of certain diseases.