Newsletter - October 2012
Capturing California's Diversity Through Cord Blood Collections
The Umbilical Cord Blood Collection Program (UCBCP) is a California state program run by a small team of dedicated people at the University of California Davis Health System located in Sacramento. The UCBCP was created by a law passed in late 2010 that recognized the urgent need for Californians to donate cord blood for public use, to increase the number of units that are available for transplant and especially those that are racially and ethnically diverse. Many Californians and others worldwide are not able to find a match for a bone marrow donor or cord blood unit, because they are of mixed heritage. The only way to fix this problem is to make sure that the National Cord Blood Inventory has units collected from donors that also have unique genetics representing a diverse family background.
There had never been a statewide program to allow public donation of cord blood in California before, which meant that almost all cord blood was being thrown in the trash. Now California has the UCBCP, funded by a fee of $2 placed on birth certificates. With approximately half a million births per year, and as many more birth certificates purchased by residents who need a new copy, we have enough money to collect cord blood at several sites across the state, allowing mothers to donate at no cost to themselves or their families. Importantly, many families cannot afford the cost of private cord blood banking, and a free public banking option allows them a chance to preserve this precious resource regardless of their economic situation. If a donation of cord blood is made and the unit is banked, the family can access that cord blood unit as long as it has not already been used for a transplant patient.
To collect as many cord blood units as possible, we are focusing on the five most populated areas of the state:
- San Diego,
- Los Angeles,
- the Central Valley,
- the San Francisco Bay area, and
In San Diego and Los Angeles we are working with two California cord blood banks to increase the number of hospitals at which they will offer public cord blood donation and banking services. Currently mothers can donate cord blood at four hospitals in Southern California, and over the next several months that number is set to increase to over twenty hospitals. In Northern California and the Central Valley, we are working to set up new collection sites to serve areas that haven't been served before, like Sacramento. We were very excited to start pilot collections at UC Davis Health System in September, for the purposes of testing our equipment and procedures, and for training. We hope to be collecting at up to four hospitals in the Sacramento area by the end of the year. Sacramento is one of the most racially diverse cities in the nation, and we are proud to be on the cusp of helping to improve the availability of cord blood units to under-represented patients in need.
Soon, when a mother arrives to deliver her baby at one of our participating hospitals, she will be asked whether she would like to donate her baby's cord blood after the birth. She will be made aware that there is no risk to herself or her baby, and that her donation may save a life, or even many lives. This is because some cord blood units that are collected do not have enough cells to be used for a transplant, and in California, if the mother consents, units that cannot be banked will be sent to researchers working to find new and better ways to use cord blood to treat and cure diseases. In this way, no cord blood is wasted, and each one that is donated has the potential to be life-saving.
Keeping Your Baby's Precious Cells in "Suspended Animation"
Being able to keep the important stem cells in cord blood and birth tissues alive and stored for a long period of time is the key to the utility of "banking" them for later use. This is achieved by freezing, or cryopreservation, of the cells; but how to effectively accomplish this is a bit more complicated than as if storing leftovers in the kitchen freezer.
If these precious cells were simply placed into freezing temperatures, they would almost all be destroyed due to massive and uncontrolled ice formation that can rupture the cells. It should be no surprise that quite a bit of the cell is made up of water. When subjected to freezing temperatures, water transitions to ice crystallization. This needs to be done in a controlled manner because if the rate is too fast there may be too much damaging ice formed inside the cells, but if the rate is too slow then the cells will be exposed too much to the salty environment left after ice forms from water around the cells. This balance is like a "Goldilocks Effect" (not too fast, not too slow).
Therefore, a foundation for preserving the cells is to control the formation of ice, and then to reduce the stresses that cells would encounter during the process of freezing and thawing. In order to effectively accomplish these goals following isolation of the stem cells, the cells are placed in a cryopreservation solution containing cryoprotectants, introduced to a controlled freezing process at a specific rate of cooling ("slow freeze"), stored at very low freezing temperatures (much colder than the leftovers in the kitchen freezer!), thawed quickly ("fast thaw"), and then appropriately applied to the patient.
The cryopreservation solutions used in stem cell therapies utilize cryoprotectant compounds within a liquid formulation. The cryoprotectants act to reduce cellular damage from ice crystal formation. The most common mechanism for this with therapeutic cells is to utilize a single cryoprotectant that permeates the cells, and promotes dehydration of the cells so there is less likelihood for formation of ice crystals inside the cells. In addition, newer cryopreservation solutions also use a mixture of salts and sugars to "buffer" the cells during this cold exposure (similar to putting a "coat" on the cells to protect them from the cold), as well as to incorporate multiple cryoprotectants, to enhance the protection of the cells.
Another important detail is the temperature that the cells are kept for long term storage. For reference, a standard kitchen refrigerator freezer is often in the range of -5°C to -10°C. Even though this is "frozen" to the naked eye, cellular activity is not effectively suppressed until stored below a point called the glass transition temperature, and cellular degradation will continue to occur if the storage temperature is not cold enough. Therefore, for long term biopreservation, cord blood banks store cells at temperatures of -130°C or colder.
Imagine, for a moment, all the stresses and variations the cells are subjected to when going from inside the mother's warm body, to being transported to the processing lab, chilled and then frozen at cold temperatures, thawed back to a warm temperature, and finally introduced into a patient. There is only a limited number of precious stem cells in cord blood and birth tissue, and they may not be needed for many years after childbirth. So the cryopreservation of these cells is a controlled and scientific process in order to keep those valuable cells alive in sufficient numbers, and with functional viability to allow for therapeutic benefit. Should those cells be needed one day down the road, the last thing you would want to deal with would be not having enough precious cells survive the cryopreservation process.
New Therapeutic Strategies for Cerebral Palsy
The discovery of stem cells (SCs) has led to an ongoing revolution of medicine. Starting back in the 1950s, blood-forming SCs were first used to repopulate a patient's immune system. This was the first example of a successful SC therapy, and is still commonly used today for blood and bone-marrow-related cancers such as leukemia and myeloma.
Recently, the biology of SCs has created novel therapies for previously intractable conditions. One area where cell therapy has generated hope is neurology. Cellular therapy of the injured brain has been studied in preclinical models for more than a decade, providing the basis for the development of new therapies for a broad spectrum of human neurological diseases. The mechanism by which transplantation of SCs leads to an enhanced functional recovery and structural reorganisation is still not understood. Nevertheless, the use of autologous bone marrow-derived SCs does not face ethical, political, biological and regulatory hurdles, like embryonic stem cells does.
Cell therapy protocols for cerebral palsy are an example of a new approach to a condition that is difficult to treat. The current US clinical trials, listed in ClinicalTrials.gov, are dependent upon the fact that parents chose to preserve their child's umbilical cord blood at the time of birth. Our clinical trial, listed as ClinicalTrials.gov NCT01019733, was carried out at a University Hospital in Monterrey, Mexico, where we treated children with cerebral palsy that were not able to bank their cord blood. Instead we use SC derived from the bone marrow.
The patients enrolled in our trial received a subcutaneous medication for 4 consecutive days to stimulate their bone marrow to produce SCs, their bone marrow was then harvested, SCs were concentrated at the laboratory, and then they were delivered through the patient's cerebrospinal fluid on the fifth day of the procedure. In this trial, we made the translation from the laboratory to the clinic both medically and economically feasible. Our team conducted a thorough evaluation of each patient, from initial interviews to the final assessments. Patients came to us from different countries, including Mexico, US, Canada, Honduras, Colombia, and Italy.
The condition and response of patients in our trial was assessed at regular intervals to ensure the safety of the therapy. Even with this small group, less than 20 patients seen over 36 months, we were able to reach our goal, which was to demonstrate the safety of the procedure. This success opens the door to a phase II clinical trial that can test the efficacy of autologous bone marrow SCs. The preliminary results regarding efficacy were promising. We cannot say more, because the data are currently under review for publication. We hope that our work will offer a better quality of life to children with cerebral palsy.
In conclusion, while the field of SC medicine is rapidly maturing, many potential SC therapies remain theoretical or restricted to successes in animal trials. Countless studies are still required on the expanding frontier of SC research before a complete mastery of SC manipulation for maximum therapeutic potential can be achieved. In the meantime, we believe that patients with cerebral palsy can be treated with their own bone marrow SCs when their cord blood SCs were not preserved.
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- Sng J., Lufkin T. Emerging stem cell therapies: treatment, safety, and biology. Stem Cells International. 2012; Article 521343. doi:10.1155/2012/521343
- Carroll JE, Mays RW. Update on stem cell therapy for cerebral palsy. Expert Opin Biol Ther. 2011; 11(4):463-71. doi:10.1517/14712598.2011.557060