How Stem Cells Are Preserved for Future Use

Stem cells are stored using advanced freezing techniques to maintain their potential for regenerative therapies. These cells, collected from sources like umbilical cord blood and placental tissue, are preserved at extremely low temperatures (-196°C) through cryopreservation methods. This process halts biological aging, ensuring the cells remain functional for decades. Here's a quick overview:

• Collection: Stem cells are sourced from umbilical cord blood, cord tissue, and placental tissue immediately after birth.
• Processing: Specialized labs isolate and prepare the cells using methods like Sepax or CryoMaxx™ Processing.
• Freezing Methods: Controlled-rate freezing and vitrification prevent ice damage, safeguarding cell structure.
• Storage: Cells are kept in liquid nitrogen at -320°F, with strict monitoring for temperature stability.
• Thawing: Careful rewarming ensures cells retain their functionality for therapeutic use.

These preserved cells are vital for treating cancers, blood disorders, and tissue repair. Facilities like Americord Registry ensure high viability and quality through rigorous testing and storage standards.

Stem Cell Collection and Processing

Sources of Newborn Stem Cells

Newborn stem cells come from umbilical cord blood, cord tissue, and placental tissue - all rich sources of valuable cells.

Cord blood is packed with Hematopoietic Stem Cells (HSCs), essential for forming blood and immune systems. These cells are already approved by the FDA to treat more than 80 diseases, including conditions like leukemia, lymphoma, and sickle cell anemia. Globally, over 60,000 cord blood transplants have been performed to address a variety of health challenges.

Cord tissue, on the other hand, contains Mesenchymal Stem Cells (MSCs), which are being heavily researched for their potential in tissue repair and regeneration. In fact, more than 200 clinical trials are exploring how these cells might help with diseases like Parkinson's or heart disease. Similarly, placental tissue provides MSCs with comparable regenerative properties.

The collection process is quick and straightforward. After the umbilical cord is clamped, healthcare providers collect 2–3 ounces of cord blood and segments of cord tissue using sterile tools. This takes just a few minutes, ensuring the cells are ready for immediate processing to maintain their viability for storage.

Processing Techniques for Stem Cells

Once collected, the stem cells need to be processed quickly to preserve their quality. The materials are sent to a lab via medical courier, where specialized techniques isolate and concentrate the stem cells for storage. For cord blood, removing red blood cells during processing enhances both safety and effectiveness for future transplants.

Laboratories use advanced systems like Sepax or AXP, along with proprietary methods such as Americord Registry's CryoMaxx™ Processing, to ensure the highest standards. These methods aim for a cell survival rate of 90% or more. The entire process, including adding cryoprotectants, is completed within 48 hours.

Cryoprotectants like DMSO or glycerol are added to shield the cells during freezing. These compounds prevent ice crystals from forming, which could damage cell membranes. Once processed, the stem cells are cryopreserved in specialized storage facilities, ensuring they remain viable for potential therapeutic use in the future.

Cryopreservation Methods for Stem Cells

After processing, stem cells must be frozen using techniques that safeguard their structure and functionality. The aim is to preserve these cells for decades while ensuring they remain viable and effective when thawed. The three primary methods used are controlled-rate freezing, vitrification, and storage in liquid nitrogen.

Controlled-Rate Freezing

Controlled-rate freezing involves gradually lowering the temperature - typically at a rate of -1.8°F per minute (-1°C per minute) - to protect cells from damage. This slow cooling process allows water to leave the cells, reducing the risk of large ice crystals forming inside. Such crystals could rupture cell membranes and diminish the cells' therapeutic properties.

The process starts by cooling the stem cells to -112°F (-80°C) overnight, often using programmable freezers or passive cooling containers. During this step, cryoprotectants like DMSO (dimethyl sulfoxide) are added to shield the cells from damage caused by rising solute concentrations as ice forms outside the cells. Together, slow cooling and cryoprotectants minimize ice-related harm.

"Controlled-rate freezing, a method that involves a gradual cooling rate of -1°C/minute, before long-term storage can help maximize cell viability and integrity." - STEMCELL Technologies

Unlike this method, vitrification takes a more aggressive approach to prevent ice formation entirely.

Vitrification for Ice Crystal Prevention

Vitrification avoids ice formation by using high concentrations of cryoprotective agents (6 to 8 M) to turn the liquid into a glass-like state. This high viscosity prevents water molecules from organizing into ice crystals, which can damage the cells' structure.

This technique is especially effective at preserving the three-dimensional structure of cells, as it eliminates the risk of ice-related disruptions. Research indicates that vitrified Hematopoietic and mesenchymal stem cells maintain approximately 89% viability and normal growth over five passages. However, the method requires ultra-rapid cooling and rewarming to maintain the glassy state and prevent issues like devitrification during storage or thawing.

Storage in Liquid Nitrogen

After freezing, stem cells are transferred to long-term storage in liquid nitrogen, maintained at -320°F (-196°C). At this ultra-low temperature, cellular metabolism halts entirely, ensuring the cells remain preserved for decades.

This cryogenic environment, ranging from -211°F to -320°F (-135°C to -196°C), provides the stability needed for extended preservation. While initial cooling at -112°F (-80°C) is effective in the short term, it cannot sustain viability over time. Liquid nitrogen storage ensures the long-term potential of stem cells by maintaining consistent, extremely low temperatures. Facilities equipped with cryogenic tanks and monitoring systems play a critical role in maintaining these conditions.

At Americord Registry, these advanced cryopreservation techniques are used to secure the therapeutic potential of newborn stem cells for the future.

Storage Conditions and Quality Control

Cryogenic Facility Standards

Stem cell storage facilities are designed to maintain extreme temperatures - at or below -320°F (-196°C) - to effectively halt biological activity. For instance, at Americord Registry, cryogenic tanks are equipped with high-temperature alarm systems that notify staff immediately if there’s any temperature fluctuation. This rapid response system helps protect against potential losses caused by equipment failures. Additionally, the facilities function as cleanrooms, incorporating advanced air filtration systems to minimize contamination risks.

Beyond temperature control, these facilities continuously log temperature and CO₂ levels. This data serves dual purposes: meeting regulatory compliance and providing a detailed record for quality checks. By monitoring even minor fluctuations, the integrity of the stored cells remains uncompromised. This meticulous approach, paired with advanced preservation methods, ensures that stem cells stay viable and ready for therapeutic use.

Viability Testing Protocols

While maintaining proper storage conditions is essential, rigorous testing ensures that stored cells remain functional. Before preservation, cells undergo thorough screening for contamination and viability. A commonly used test is the Trypan Blue exclusion test, which differentiates between live cells (those that exclude the dye) and dead cells (those that absorb it).

However, as experts at Cellbox Solutions emphasize:

"It is a dangerous misconception to equate cell viability with cell functionality. In the context of cell therapy, mere survival is not sufficient."

This is why quality control includes functional testing. These assessments determine if the cells can proliferate, differentiate, and perform their intended biological roles. For example, tests may confirm that stem cells can develop into specialized cell types without undergoing unwanted changes during storage. Studies show that dental pulp-derived stem cells retain their full functionality for at least six months at -121°F (-85°C) or -320°F (-196°C). Even after being stored in liquid nitrogen for over two years, such cells have demonstrated normal differentiation and proliferation once thawed.

This comprehensive quality control process ensures that stem cells are therapeutically ready whenever they are needed.

Thawing and Future Applications

Safe Thawing Techniques

Cryovials are transferred straight from -196°C storage into a 37°C water bath to minimize ice crystal damage.

"The thawing procedure is stressful to frozen cells. Using good technique and working quickly ensures that most cells survive the procedure."

The process is quick - usually under a minute. Technicians gently swirl the vial in the water bath until only a small piece of ice remains. Afterward, the vial's exterior is wiped with 70% ethanol to maintain sterility, and the cells are added drop by drop into pre-warmed medium to reduce osmotic shock.

Since DMSO becomes toxic at room temperature, it must be removed promptly. This is done by centrifuging the cells at around 200 × g for 5–10 minutes, which separates the cells from DMSO. The cells are then resuspended in fresh medium. Every step is carried out under sterile conditions with the appropriate safety protocols in place.

These careful methods ensure that cells remain viable and ready for use in regenerative therapies.

Potential Therapeutic Uses

Once thawed correctly, preserved cells open doors to a variety of regenerative treatments. Stem cells, for example, play a key role in these therapies. Hematopoietic stem cells from cord blood are used to treat cancers and blood-related conditions. Mesenchymal stem cells are being explored for their ability to repair musculoskeletal tissues. Adipose-derived stem cells offer a convenient source for tissue engineering, while dental pulp-derived stem cells maintain their ability to differentiate and proliferate even after extended cryogenic storage.

Robin Sieg and Prof. Dr. Kathrin Adlkofer from Cellbox Solutions emphasize:

"In the context of cell therapy, mere survival is not sufficient, cells must be capable of targeted action, engraftment, proliferation, and the execution of specific biological functions."

This distinction is crucial, especially since post-thaw viability can sometimes fall below 70%. At Americord Registry, preserved cord blood, cord tissue, placental tissue, and exosomes are rigorously tested to ensure they remain ready for therapeutic use. Their CryoMaxx™ processing and storage protocols are designed to maximize cell recovery while safeguarding the biological functions needed for future medical applications - whether for treating blood disorders, aiding tissue repair, or advancing new immunotherapy techniques.

Conclusion

Preserving stem cells serves as a form of biological insurance, safeguarding cells at their prime, youthful state. With established cryopreservation techniques, every step is carefully designed to protect cellular structure and maintain their therapeutic potential.

Cryopreservation science has shown impressive results. Research confirms that stem cells stored in liquid nitrogen can remain viable for decades, giving families confidence in the long-term reliability of newborn stem cell banking.

Privately stored stem cells provide a perfect genetic match for the child and may also serve as potential matches for siblings, ensuring quick access when needed. Americord Registry's CryoMaxx™ processing ensures that cord blood, cord tissue, placental tissue, and exosomes are preserved with at least 90% viability - critical for achieving the best therapeutic results.

Stem cell banking also holds promise for the future of regenerative medicine. As advancements continue, these preserved cells could play a role in treatments like tissue repair, immunotherapy, and other medical innovations still on the horizon. Selecting a facility that adheres to international standards, employs rigorous quality controls, and has reliable cryogenic backup systems is essential to ensure the safety and longevity of stored cells. This careful process secures a valuable resource for future medical needs.

FAQs

How long can stem cells stay usable in liquid nitrogen?

Stem cells kept in liquid nitrogen can stay viable for an incredibly long time - potentially over 200 years - while still retaining their functionality. Maintaining the right storage conditions is key to ensuring their preservation and continued usability.

What’s the difference between cord blood and cord tissue stem cells?

Cord blood is rich in hematopoietic stem cells, which are responsible for forming blood and immune cells. These cells are commonly used in treatments for various blood-related conditions. In contrast, cord tissue contains mesenchymal stem cells, which have the ability to develop into cells such as bone, cartilage, and fat. Researchers are exploring their potential use in regenerative therapies. The main distinction lies in the type of stem cells each contains and their respective uses.

What happens if the storage tank temperature changes?

If the temperature in a storage tank fluctuates, cryopreserved stem cells and tissues can suffer damage. Even slight warming can compromise the samples, making them unusable. Maintaining consistent temperature control is essential to protect the integrity of these preserved materials.