Stem cell preservation involves collecting and storing biological cells for future medical use. These cells hold potential for treating various diseases and conditions due to their regenerative capabilities. This process ensures the cells remain viable over extended periods for therapeutic applications.
Understanding Stem Cells and Preservation
Stem cells are distinctive biological cells recognized by two primary characteristics: their ability to self-renew and their capacity to differentiate. Self-renewal means they can divide and create more cells identical to themselves, maintaining an undifferentiated state. Differentiation refers to their potential to develop into many specialized cell types, such as blood, nerve, or heart muscle cells. This dual capability makes them fundamental to the body’s repair and maintenance processes.
Stem cell preservation involves collecting these cells and maintaining their viability for long-term storage. This ensures they are available when needed for research or clinical applications.
Where Stem Cells Come From
Stem cells can be obtained from several sources. Umbilical cord blood is a readily available source, rich in hematopoietic stem cells (HSCs) that form various blood and immune system cells. It is collected immediately after birth, a safe and non-invasive process for both mother and baby. Cord blood stem cells are considered more adaptable than those from bone marrow, with a lower risk of immune complications in transplants.
Umbilical cord tissue, specifically Wharton’s jelly, is another valuable source. This tissue contains mesenchymal stem cells (MSCs), which can differentiate into various cell types, including bone, cartilage, and fat. MSCs from cord tissue are being extensively researched for their potential in regenerative medicine.
Bone marrow has traditionally been a significant source of stem cells, particularly HSCs, used in transplants for many decades. While effective, obtaining bone marrow stem cells is a more invasive procedure compared to cord blood collection. Adipose (fat) tissue also contains MSCs, offering another accessible source.
How Stem Cells Are Preserved
The primary method for preserving stem cells is cryopreservation, which involves cooling biological material to extremely low temperatures to halt biological activity. This process effectively puts cells into a state of hibernation, allowing them to remain viable for extended periods, potentially decades. Preventing the formation of ice crystals, which can damage cell structures, is important.
To mitigate ice crystal formation, cryoprotectants like dimethyl sulfoxide (DMSO) are introduced. These substances lower the freezing point and prevent water from forming damaging ice crystals by binding with water molecules and altering cell membrane permeability. The cells are then subjected to a controlled cooling process, typically at a rate of about 1 degree Celsius per minute. This gradual cooling allows cryoprotectants to penetrate the cells and minimize cellular damage.
After controlled cooling, the cells are plunged into liquid nitrogen, reaching temperatures as low as -196°C (-320°F). At these ultra-low temperatures, all metabolic and enzymatic activities within the cells virtually cease. When needed, the cells are rapidly thawed, and cryoprotectants are removed, ensuring the cells remain functional for their intended therapeutic use.
Current and Future Medical Uses
Preserved stem cells are currently used to treat a wide range of medical conditions, particularly those affecting blood and the immune system. Stem cell transplants, often called bone marrow transplants, are established treatments for various blood cancers like leukemia and lymphoma, and certain blood disorders such as aplastic anemia and sickle cell disease. These transplants replace damaged blood-forming cells with healthy ones, restoring the body’s ability to produce new blood cells after intensive treatments like chemotherapy.
Beyond established therapies, preserved stem cells hold promise for regenerative medicine, which focuses on repairing or replacing damaged tissues. Research is ongoing into their potential to treat neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and multiple sclerosis, exploring their ability to regenerate neural tissue or provide neuroprotective support. Stem cells are also being investigated for treating conditions like heart failure, spinal cord injuries, and diabetes. These future applications aim to harness the regenerative capacity of stem cells to address conditions lacking effective treatments.