Mesenchymal stem cells (MSCs) have great potential in the field of regenerative medicine. Their unique ability to give rise to multiple cell types including bone, cartilage and fat, contributes to their therapeutic potential. Isolating and culturing these stem cells is key in order to leverage their full potential, yet. The following article delves into the complex processes that make up the isolation and culture of MSCs and how they serve as “seeds of regeneration” leading to advances in tissue engineering and medical treatments.
What Are Mesenchymal Stem Cells?
MSCs are multipotent cells found in different tissues such as bone marrow, adipose tissue, and umbilical cords. Whereas hematopoietic stem cells mainly produce blood cells, MSCs can differentiate toward multiple lineages, which makes them important for tissue repair and regeneration. Due to their nature, they are a very important piece in the puzzle of regenerative therapies against osteoarthritis, cardiovascular diseases, and spinal cord injuries.
The first step: Isolating MSCs
Isolation of MSCs is an important process that affects the cell quantity and viability for the therapeutic use. MSCs may be extracted from various tissues, with bone marrow and adipose tissue as the most frequently used sources. The tissue for MSCs is obtained through biopsy (bone/bone marrow) or liposuction (adipose tissue)28 and then isolated to obtain the desired cells. The collected sample is then digested with enzymes that break down the extracellular matrix, thus freeing the stem cells from their local tissue.
The digestion product is then centrifuged to isolate the MSCs from the other cell types. The cells are then washed multiple times to further purify the sample. Third, the MSCs are plated on culture dishes, where they stick to the plastic and separate themselves from non-adhering cells. Adherent cells are usually fibroblast-like, suggesting that they are MSCs.
What is the process for culturing MSCs?
Isolated MSCs are required to be cultured in ideal conditions that support their growth and preserve their stemness properties. Type of culture medium used is one of the essential factors that influence the cells’ viability and differentiation. Most MSCs in vitro culture mediums comprise of DMEM medium enriched with FBS and necessary supporting growth factors like FGF and PDGF.
Within the incubator, temperature, humidity and oxygen levels are also carefully controlled. This way, the cells are kept in similar conditions to conditions found in the human body and must be preserved at 37°C with an atmosphere saturated with 5% CO2. Additionally, the oxygen levels in the incubator can also be lowered to approximately 2-5%, mimicking the hypoxic conditions under which MSCs are typically found.
MSCs should be passaged due to overcrowding, which can cause changes in behaviour and increased differentiation capacity. This process—called passaging—occur when researchers use a proteolytic enzyme called trypsin to un-stick the cells from the culture surface, then place them in new culture dishes to continue expanding.
Low Risk — Ensuring Culture Quality and Purity
MSC in culture is a highly versatile population, and represents a key determinant of therapeutic efficacy. Several characterization tests are conducted to confirm that the cultured cells are, in fact, MSCs. According to the International Society for Cellular Therapy (ISCT), these mesenchymal stem cells (MSCs) should possess the following characteristics; surface expression of surface markers (CD73, CD90, and CD105) and lack of hematopoietic markers (CD34 and CD45).
Flow cytometry is a common way to confirm the presence of these markers. In addition, MSCs should be able to differentiate into osteoblasts, chondrocytes, and adipocytes when cultured under appropriate conditions Given their inherent capability to differentiate into multiple lineages, MSCs are also known as multipotent stem cells. The functional tests add to the validation of the multipotency of the cultured MSCs and their potential for regenerative use.
Applications in regenerative medicine
After isolation and expansion, mesenchymal stem cells (MSCs) can be used for various therapeutic applications. Tissue engineering is one of the most exciting areas of research into these cells, where MSCs are being used to generate tissues in the laboratory, or repair damaged tissues. MSCs are also seeded onto scaffolds to form cartilage tissue for osteoarthritis treatment or used in bone grafts for bone regeneration.
Moreover, MSCs have profound immunomodulating effects, enabling them to be utilized for treating inflammatory diseases like Crohn’s disease and multiple sclerosis. Their capacity to conveniently modulate immune responses while not triggering potent rejection makes MSC-based therapies very appealing for allogeneic transplantation.
Summary
Mesenchymal stem cells are delicate and isolating and culturing them is an art all of its own requiring high levels of precision and care, however, the rewards can be staggering. Once they have been properly nurtured, these so-called “induced pluripotent stem cells” could transform medicine, offering new treatments for diseases once thought incurable. Growing bodies of knowledge are establishing links, and the “”regeneration seeds”” may then be a budding star of a new generation of regeneration therapies that will bring the future of medicine and healing.