Regenerative medicine is a cutting-edge medical field that aims to restore the function of tissues and organs damaged by disease or injury.
Compared to traditional treatment methods, this allows for the regeneration of tissues previously difficult to repair, and by leveraging the patient's own cells, we aim to achieve treatment with minimal adverse effects.
Among these cells, stem cells are specialized cells that possess the ability to differentiate into various cell types and the capacity for self-renewal through self-replication.
Leveraging these characteristics, stem cell therapy is widely applied in tissue regeneration and disease treatment. Research and practice in this field continue to advance across numerous domains, including neurological, cardiovascular, and joint diseases, and even immune-related therapies.
Types of Stem Cells
Types of Somatic Stem Cells
Stem cells present in various body tissues comprise many types, including hematopoietic stem cells, neural stem cells, skin stem cells, intestinal stem cells, mammary stem cells, testicular stem cells, and mesenchymal stem cells.
Stem cells possess "self-renewal potential," which allows them to proliferate and maintain their population, and "differentiation potential," which enables them to divide and mature into various cell types.
Among somatic stem cells, mesenchymal stem cells, which differentiate into the widest range of cell types, are key players in current stem cell therapy. Their differentiation potential is extensive, including hematopoietic system cells, nervous system cells, epidermal cells, cartilage, muscle, liver, and cardiac cells.
Three Main Types of Stem Cells in Regenerative Therapy
There are three broad categories of stem cells used in regenerative medicine:
- ES cells (embryonic stem cells):Derived from blastocyst embryos and can differentiate into all cells. However, its use is limited due to ethical issues.
- iPS cells (induced pluripotent stem cells):Made by reprogramming somatic cells. High differentiation capacity, but there is a risk of tumor formation.
- Somatic stem cell (adult stem cell)It is already present in the human body, there are no ethical issues, and its safety is high, making it the most practical at present.
In the context of stem cell therapy, endogenous somatic stem cells are currently the safest and most practical option, posing no ethical concerns.
Types of Mesenchymal Stem Cells
Mesenchymal stem cells (MSCs) are a type of stem cell found in bone marrow, adipose tissue, and the umbilical cord, possessing the ability to differentiate into bone cells, cartilage cells, fat cells, nerve cells, muscle cells, and various other cell types.
Furthermore, MSCs possess tissue repair capabilities and immune regulatory functions, and are applied in the treatment of various diseases. Research and clinical applications continue to expand, particularly in the fields of joint diseases, neurological diseases, cardiovascular diseases, and autoimmune diseases.
Mesenchymal stem cells used in regenerative therapy can be classified into three main types based on their source of isolation.
Mesenchymal Stem Cells from Bone Marrow
- Formerly the standard in regenerative therapy, but is currently transitioning to other MSCs.
- Possesses a good balance between self-replication capacity and differentiation potential.
- Possesses a relatively high immunoregulatory capacity and is applied in the treatment of autoimmune diseases.
Adipose-derived Mesenchymal Stem Cells
- Minimal physiological impact is observed, allowing for the collection of a significant quantity of cells. (Harvested via liposuction under local anesthesia.)
- Culture can readily propagate within a relatively short timeframe.
- It exhibits anti-inflammatory effects and is utilized in the treatment of inflammatory diseases.
Mesenchymal Stem Cells from Umbilical Cord
- Exhibiting the highest proliferative capacity and maintaining cells in a youthful state.
- Low immunogenicity and suitable for allogeneic transplantation, with a low risk of rejection.
- The collection is straightforward, with minor ethical considerations. (It is obtained from the umbilical cord of a newborn baby, posing no burden on the donor.)
- It secretes numerous growth factors and anti-inflammatory cytokines, and therapeutic effects are anticipated.
Autologous Stem Cells versus Allogeneic Stem Cells
- Sel punca autolog:A treatment method in which stem cells taken from the patient's own body are cultured, expanded, and reintroduced into the body.
- Sel punca allogeneic:A treatment method that uses stem cells taken from a healthy donor.
Three Effects of Mesenchymal Stem Cells
Mesenchymal stem cells (MSCs) possess the ability to repair and immunoregulate various tissues throughout the body. Their mechanism of action is manifested through three primary mechanisms:
Pasotrophic Effect
When inflammation or tissue damage occurs within the body, MSCs possess the ability to detect chemokines (inflammatory signals) emitted from the affected area and migrate to the site of damage via the bloodstream. This characteristic enables MSCs to accumulate near the damaged tissue and initiate repair. Specifically, they interact with fibroblasts, vascular endothelial cells, and immune cells to support tissue repair.
POIN:The pasotrophic effect serves as a "first step" where MSCs move to the appropriate location.
Homing Effect
Upon MSC migration to areas of inflammation or damage, they home to these sites and contribute to tissue repair. During this process, MSCs not only differentiate into locally required cells but also secrete cytokines and growth factors that facilitate repair, thereby supporting the restoration of function in the damaged tissue.
At the site of injury, inflammatory cytokines and growth factors are locally elevated, attracting MSCs. Upon receiving these signals, MSCs interact with vascular endothelial cells and fibroblasts to effect tissue repair.
POIN:Through the homing effect, MSC accurately reach areas of inflammation or damage and address the "second stage" of repair.
Paracrine Effect
MSCs secrete biologically active substances such as cytokines, growth factors, and exosomes, thereby promoting the repair of damaged tissues. In this manner, MSCs can support the functional recovery of surrounding cells even without directly differentiating. Notably, they possess immunomodulatory effects, regulating immune cell activity and suppressing inflammatory responses.
This effect is crucial in the treatment of autoimmune and chronic inflammatory diseases, simultaneously modulating immune cell activity and suppressing an overactive inflammatory response.
POIN:Tissue repair is promoted by secreted factors even without MSCs differentiating directly, and it is considered that most of the therapeutic effects of MSCs in regenerative therapy originate from these paracrine effects.
Benefits of Mesenchymal Stem Cells from Umbilical Cord (Wharton's Jelly)
Mesenchymal stem cells derived from the umbilical cord (Wharton's Jelly) are expected to exhibit high therapeutic efficacy due to their characteristics.
Considering only the risk of immune rejection, autologous stem cells may appear safest; however, their proliferative and differentiation capacities diminish with advancing age.
Furthermore, information regarding pre-existing conditions is also retained within cultured cells, potentially elevating disease risk.
Autologous stem cells are an individual's own cells, the function of which diminishes with age.
Umbilical cord-derived mesenchymal stem cells (Wharton's Jelly) are isolated from the Wharton's Jelly of newborn umbilical cords, offering the significant advantage of no cellular degeneration due to aging.
Furthermore, umbilical cord tissue contains a high number of mesenchymal stem cells, and compared to cells derived from bone marrow or adipose tissue, their proliferative capacity is higher, and their differentiation potential can be maintained for a longer period.