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Cord blood banking has become a vital element of a family healthcare strategy. The pluripotent haematopoietic stem cells (HSCs) play a leading role in regenerative medicine. The applications of these stem cells have broadened, from being used to treat life-threatening diseases, including various types of Leukaemia and immune disorders, to a multitude of genetic disorders. This article attempts to offer parents a concise overview of the key techniques stored for collecting and storing cord blood stem cells after birth, thereby encouraging them to preserve their baby’s life-saving stem cells.
The Value of Cord Blood
Umbilical cord blood is rich in Haematopoietic Stem Cells that act as the foundation of the blood and immune system. Unlike adult stem cells sourced from bone marrow, they are younger and more adaptable, significantly reducing the chances of graft-versus-host disease (GVHD) in the case of allogeneic transplant.
Why Preserve Stem Cells
Allogeneic and autologous transplants of stem cells have evolved as the standard treatment for over 80 illnesses such as Leukaemia, Lymphoma, Hodgkin’s disease, sickle cell anaemia, thalassaemia major, immune system disorders and Metabolic disorders. Further, umbilical cord blood banking has opened up new avenues in the field of regenerative medicine for joint repair, autoimmune conditions, and even HIV Remission.
The Collection Process
The cord blood collection process is elaborate, starting several months before delivery and culminating in a cryopreservation facility.
Step 1: Enrollment
Parents enrol in a cord blood bank months before the due date from here. They are then sent a sterile cord blood collection kit box containing components for sample collection. The following is a step-by-step cord blood preservation process after delivery of the baby.
Step 2: Collection Procedure
The procedure of stem cell preservation for newborns starts minutes after the delivery of the baby. In-Utero versus Ex-Utero Collection:
- In-Utero Collection
In this method, the collection takes place while the placenta is still inside the mother. A phlebotomist washes the umbilical cord with a disinfectant and then injects a needle into the umbilical vein, and gravity causes the blood to flow into a sterile collection bag. This type of collection is usually better for maximising the volume of cord blood, as the flow of blood will be greater before the clotting begins.
- Ex-Utero Collection
After the delivery of the placenta, a medical team carries it to a separate station where the remaining blood is drained into a bag. This is often used for C-sections or difficult deliveries where the mother and baby require more immediate attention.
Step 3: Logistics and Transportation
Stem cells are living organisms that become inactive if kept at room temperature for too long. Accredited laboratories insist on receiving the sample within 36 to 48 hours. The initial steps of the cord blood banking process include utilising temperature-controlled logistics services that streamline logistics to ensure the delicate DNA of the stem cells remains intact.
Temperature Control
The sterilised collection kit box is fitted with thermal insulation and cooling packs to ensure a constant and controlled temperature is held during the transit period. This prevents any early cell death of stem cells through apoptosis.
Step 4: Laboratory Procedure
Once the sample arrives at the lab, it goes through a series of processes described below:
Volume Reduction
In its native state, the cord blood includes red blood cells and plasma. These could impede the cryopreservation process. The lab carefully extracts the “buffy coat”, or thin layer of white blood cells that includes highly concentrated stem cells. Thereby reducing unnecessary red blood cell volume to optimise cord blood stem cell storage and limit side effects like kidney problems due to lysed red blood cells, which could occur if a patient were to receive a transfusion later in life.
Automated Processing Systems
The best method for cord blood stem cell preservation includes automation to increase the precision.
- PrepaCyte-CB
This is considered a highly sophisticated process that offers the highest recovery of usable stem cells, while eliminating the largest percentage of red blood cells.
- Centrifugation
This is one of the cord blood processing methods that involves spinning the blood at very high speed to separate components by density. Generally, a slightly smaller cell count is recovered when compared to automated sedimentation procedures.
Stage 5: Cryopreservation and Storage
The final, most technical stage in the process is the suspended animation of the stem cells.
Cryoprotectants
The procedure of cord blood cryopreservation starts with adding cryoprotectant (generally Dimethyl Sulfoxide or DMSO) to the cells before freezing. DMSO prevents the formation of sharp ice crystals within the cells that would rupture the cell membranes and kill them as they freeze.
Controlled-Rate Freezing
State-of-the-art stem cell storage techniques dictate that the cells be frozen very slowly (at 1 degree Celsius/min). The use of a Controlled-Rate Freezer achieves this goal. This prevents thermal shock from killing the cells.
Vapor-Phase Liquid Nitrogen
- Risks of the Liquid Phase
The drawback to storing samples in the liquid phase is that if a sample bag develops a tiny leak and is submerged directly in liquid nitrogen, other samples can be contaminated through any resulting fluid exchange.
- The Safety of the Vapour Phase
By storing the samples in the ‘vapour’ of the freezer just above the liquid, the optimal cord blood storage temperature is maintained while the risk of contaminants moving from sample to sample in a liquid carrier is eliminated.
Conclusion
Collecting cord blood is a precious one-time opportunity. The answer to what happens to cord blood after delivery is pivotal in deciding the future health of a family.