Cord Blood Banking: A Novel Idea

What is Cord Blood?
Cord blood means a blood that remains in the umbilical cord and the placenta after a baby is born. Afterbirth, cord and placenta were discarded as medical waste. Recently, it is been found that, cord blood has rich source of stem cells that can be stored and in future it can be used for different hematological and genetic diseases. Getting stem cells from the umbilical cord and placenta is painless and safe procedure for the mother and her child.

Cord blood contains stem cells that are the building blocks of the blood and immune system. They have the ability to develop into other types of cells, so they can help to repair tissues, organs, and blood vessels and can be used to treat a host of diseases. The cord blood is composed of all the elements found in whole blood. It contains red blood cells, white blood cells, plasma, and platelets and hematopoietic stem cells. The oldest cord blood stored still is in perfect condition after 23 years.


Fig. 1 : Cord tissue and Placenta after birth.

Cord blood bank

Cord blood banking means collecting and storing the blood drawn from the umbilical cord after a baby is born. Cord blood bank is a facility, which cryopreserve umbilical cord blood in liquid nitrogen in -1960C for future medical use. In addition to cord blood; Cord tissue, placenta, amniotic fluid, amnion are also stored for future medical treatments.

There are two types of cord blood banks available. A public bank where cord blood can be donated for free, and it may be helpful for patients seeking stem cells for a transplant. In Public cord blood bank, HLA typed cord blood is open for transplant registry, where patient in need of cord blood or hematopoietic stem cells can access HLA registry and find suitable match for the transplant. A family or private cord blood bank also saves cord blood for a fee and it will be exclusively for the family use only. This bank do not facilitate registry for transplant purpose.

Who should do cord blood banking
Cord blood banking is encouraged because of the recent advancement in the field of stem cells and regenerative medicine. Clinical application of cord blood, cord tissue or placental derived stem cells is getting recognition due to ample availability and less ethical concern. In fact, these are the only adult stem cells of 9-month age. Importantly, collection of cord blood stem cells is done by non-invasive methods or dose not requires any surgical intervention to collect stem cells. Many parents who are more health conscious tend to opt for the cord blood banking. There are two options available with the majority of time. Financially affordable parents go for family or private cord blood banking. Now day’s parents also attracted to donate the cord blood to public banks but the awareness is very low and there are very few public cord blood banks available.

Patient who have genetic history of cancer, diabetes should be encouraged to do cord blood banking. Similarly, population which is exposed to hazards chemicals or pollution should also be consider under this option

Why to do cord blood banking?
Cord blood contains stem cells that may be cryopreserved (Stored in -1960C) for later use in medical therapies, such as hematopietic stem cell transplants. Both private and public cord blood banks have developed in response to the potential for cord blood in treating diseases of the blood and immune systems. Public cord blood banks accept donations to be used for anyone in need, and as such function like public blood banks. Private cord blood banks store cord blood only for potential use by the donor or donor’s family. Cord blood transplants require less stringent matching between the tissue types of the donor and patient, known as their human leukocyte antigen (HLA) types. Bone marrow transplants require a complete match on six key antigens, which are measures of graft-versus-host reaction, known as a 6/6 match. Cord blood transplants achieve the same medical success with only a 4/6 match. HLA type is inherited from both parents, so siblings are particularly likely to be a match, and people from the same ethnic heritage are more likely to match. Minority ethnic groups have difficulty finding a perfectly matched transplant donor. Studies have found that allogeneic transplants have a better outcome when the donor and patient are related. The odds that two siblings will have the 6/6 match required for a bone marrow transplant are 25%.The odds that two siblings will have the 4/6 match required for a cord blood transplant are 39%.

How is Cord blood banking done?
Once a couple decides to preserve their child’s blood/placenta/cord tissue, they sign an agreement with the company. After which a collection kit is provided to the couple with details about the collection process of cord blood/placenta/cord tissue. This kit is handed over to the obstetrician at the time of delivery.

There are several methods for the collection of cord blood. The method most commonly used in clinical practice is the “closed technique”, which is similar to standard blood collection techniques. With this method, the technician prick in the vein of the umbilical cord using a needle that is connected to a blood bag, and cord blood flows through the needle into the bag. Continuous shaking of cord blood bag is done for proper mixing of cord blood with anticoagulant agent. On average, the closed technique enables collection of about 75 ml of cord blood. Additionally, 10 ml maternal blood was collected to test for different virus.

After cord blood collection, within 48 hours of cord blood units are transported to Cord Blood Processing Laboratory where technicians “register” new units into the database, obtain aliquots (small samples) for testing and storage. Processing must be completed and cord blood units frozen within 72 hours of collection.

How cord blood Processing is done?
Cord blood processing is done in a clean room (class 10,000) consist of biosafly cabinate (Calss 100). This processing involves series of steps to remove red blood cells (RBCs) and plasma.

Before and after cord blood processing, small samples are removed to count the total nucleated cells (TNC) and the number of nucleated cells for CD34 positive cells (a marker of hematopoietic stem cells).

SEPAX® Cord Blood Processing System
The SEPAX® is a fully automated closed and sterile processing system for Cord Blood Processing. Sepex can efficiently harvests stem cells from cord blood with the highest recovery rate of above 86%. The SEPAX® Cord Blood Processing System is approved by the US Food & Drug Administration (FDA) for cord blood processing.

The cord blood bag set is placed into Sepex device, which is automatically centrifuged. The centrifugation process isolates mononuclear cells (MNCs) and transferred to freezing bag contains the 20 ml final product (on average, more than 80% of the MNCs and stem cells, along with some red cells). In this final product; cold, Dimethylsulfoxide (DMSO, 5 ml of a 20% solution) is added slowly. DMSO works as cryoprotectant that prevents ice crystals from forming inside of and destroying cells during freezing process.

Testing of cord blood units

ABO blood group and Rh typing: Cord blood group and Rh typing is determined.

Typing for HLA-A, -B and -DRB1: Typing for human leukocyte antigens (HLA) is performed on all cord blood units stored in Public banks. The family or private cord blood units dose not requires this testing.

Total nucleated cell (TNC): TNC enumeration is performed on all cord blood units before and after processing. This process will identify the stem cell yield in every process. TNC of a cord blood unit includes all nucleated cells: white blood cells and nucleated red cells.

CD34+ cell number: Hematopoietic stem cell market (CD34+ cell count and viability) is assessed in cord blood units by flow cytometry before and after cord blood processing.

Colony forming unit (CFU) assay: Assay hematopoietic colony forming cell counting is used to access the potency of cord blood units.

Bacterial culture for aerobic, anaerobic and Fungal organisms (after processing): This screening of cord blood unit is for bacterial or fungal infection. Ideally, final product should be free from any bacterial or fungal infections.

Infectious disease testing of mother’s blood: As per DCGI and FDA requirements maternal blood should be tested for antibodies to HIV-1 and 2 (with a test that detects antibodies to HIVO also), HTLV-1 and 2, HCV, HBV (anti-HBc), syphilis and malaria surface antigen.

Cytomegalovirus (CMV) testing: Maternal blood samples are tested for total antibody to CMV, indicating past or recent exposure to the virus.

Stem cell treatments using cord blood Stem cells:
Cord blood stem cell is the derived from the cord blood, which are said to be lifesaving cell as they have capacity to cure more than 80 diseases by cell based therapies. Stem cells are used as renewable source of replacement cell and tissues to treat common and serious disease without the need for organ transplant or surgeries including spinal cord injury, stroke, burns, heart disease and diabetes.

Over the last 20 years more than 20,000 patients worldwide have had used umbilical cord blood for different blood disorders. Cord blood units are used to treat children with blood disorders such as leukaemia, or genetic diseases like Fanconi anaemia. In this way, cord blood units offer a useful alternative to bone marrow transplants for some patients. It is easier to make a large HLA reservoir of cord blood units which can be stored in frozen state until it is needed. The cord blood is transplanted into the patient, where hematopoietic stem cells can make healthy blood cells and replace damaged cells.

However, There are few limitations of cord blood transplants. Treatment of adults with one cord blood unit is not possible and requires two units of cord blood. Clinical trials using “double cord blood transplantation” for adults have demonstrated outcomes similar to bone marrow transplant. Researchers are investigating tha way to expand the single cord blood unit, which can be useful for adult hematopoietic transplant.

Even the non- hematopoietic use of cord blood derives different methods in clinical science. Most important out of these non-hematopoietic cells are mesenchymal stromal cell (MSCs) and endothelial like vascular progenitors (EPCs). In which the MSCs are obtained from tissues like umbilical cord tissue, Amnion and placenta. These cells can be used in treating arthritis, spinal cord injury, and many inflammatory disorders. On going clinical studies have explored in the area of therapeutic strategies for neurological disorders like cerebral palsy, stroke and Alzheimer’s disease. Cardiomyopathy and many such disorder where in the EPCs from the UCB are used in clinical studies of vascular damaged such as myocardial infraction and cerebrovascular damage with promising result.

 

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