Cell therapy or cell-based medicine refers to the use of living cells or cellular components as therapeutic agents, in contrast to the use of non-living drugs or synthetic biologics.The concept has been employed in medical science and clinical practice since the late 19th century, but became more widely used in the second half of the 20th century, following the development of immuno-suppressive drugs and bone marrow transplantation techniques.
The use of living cells to treat disease is a rapidly growing area of biotechnology. The unique ability of stem cells to self-renew and differentiate into a wide variety of mature specialized cells, in addition to having an indefinite lifespan in culture, offers tremendous potential as a source of therapeutic intervention.
What Are Cell Therapies?
Stem cells are a type of precursor to certain types of adult cells. Typically, they have yet to mature into their specific types. Currently, there are two types of stem cells: embryonic stem (ES) cells, which have great capacity for self-renewal and pluripotency; and adult stem cells, which can self-renew but whose ability to form different tissue types is more limited.
Types of Cell Therapies
The two most common types of cell therapies that are currently in clinical trial or commercialized today are: 1) Autologous (from patients themselves) and 2) Allogeneic (from donors). These therapies are delivered by injection into specific areas of need in a patient. Examples include injecting stem cells directly into joints to help alleviate pain caused by osteoarthritis, delivering neural stem cells directly to damaged brain tissue after traumatic brain injury, or transplanting therapeutic cells into cardiac tissue to regenerate new heart muscle.
Sources of Cells
Adult stem cells are harvested from various parts of a patient’s body. Some adult stem cells come from bone marrow, some from fat tissue and others from blood or other sources. These adult stem cells are usually multipotent or pluripotent; that is, they can develop into a variety of different types of mature cells that can replace damaged tissue in many areas throughout a patient’s body. Another common source of stem cells is embryonic stem (ES) cells.
Research Applications of Stem Cells
By their very nature, stem cells can differentiate into a variety of different cell types. This is an incredible advantage that stems cells have over other potentially therapeutic cells (e.g., mesenchymal stromal cells or MSCs). The therapeutic utility of MSCs is limited to a few differentiation states—like osteoblasts, chondrocytes, or adipocytes—whereas stem cells can be directed to differentiate into many different differentiated phenotypes.
Medical Applications of Adult Stem Cells
Physicians employ adult stem cells to treat a wide variety of conditions, including cancer, heart disease, diabetes, and Alzheimer’s. Adult stem cells can be found throughout our bodies—in bone marrow, fat tissue, muscle tissue (including heart muscle), skin tissue (including hair follicles), reproductive organs (e.g., testes), bone marrow stroma, and in dental pulp. Such pluripotent cells can be isolated from autologous or allogeneic sources.
How Cell Therapies Work
Autologous cell therapies usually involve taking certain cells from a patient (usually, but not always, via biopsy), then growing more of those cells in order to produce a desired therapeutic effect. These therapies are very personalized—if you’re creating a treatment from an adult stem cell line, it will be derived from someone who shares your genetic makeup.
Hematopoietic progenitor cells, mesenchymal stem cells, adult stem cells or induced pluripotent stem cells can be isolated from a patient’s peripheral blood, bone marrow or adipose tissue and expanded ex vivo. This expansion of cell number is vital to their potential use in clinical trials or other treatments where they are needed in large numbers.