A Closer Look At Peripheral Blood Stem Cells and Its Research
Hematopoietic stem cells (HSCs), found both in peripheral blood and bone marrow, are essential for the body’s hematopoietic system, producing red blood cells, white blood cells, and platelets. Of the two, Peripheral Blood Stem Cells (PBSCs) are particularly important since they are constantly circulating in the bloodstream, allowing for the consistent replenishment of the cellular blood population over a person’s lifetime.
For stem cell transplantation, peripheral blood stem cells (PBSCs) are commonly employed. In the process of allogeneic transplantation, the PBSCs collected from a healthy donor are transplanted into the recipient, as a way to replace the faulty or diseased bone marrow. Conversely, in autologous transplantation, the patient’s own PBSCs are harvested and stored prior to receiving a heavy dosage of radiation therapy or chemotherapy.
Due to their simplified collection process and quicker engraftment than bone marrow, PBSCs (Pheripheral Blood Stem Cells) have become a preferred source of stem cells for transplantation.
They are employed to treat several disorders related to blood, including:
- Certain genetic disorders
This can restore healthy blood cell production and immune function.
The Relevance of Peripheral Blood Stem Cells
Accumulating evidence suggests that Peripheral Blood Stem Cells (PBSCs) are of great importance to the functioning of our bodies, particularly with regard to the immune system and in the advancement of regenerative medicine.
In the Immune System
Our immune system needs a regular supply of blood cells to stay healthy. Peripheral Blood Stem Cells (PBSCs) play an important role here, generating more blood cells, including crucial white blood cells, used to fight diseases and uphold overall health. If it weren’t for PBSCs, our immune system would quickly become impaired.
The potential of peripheral blood mesenchymal stem cells (PBSCs) for regenerative medicine is immense, as it has been shown that they can transform into various types of blood cells. These cells are commonly used in stem cell transplants for people who suffer from different blood-associated illnesses and conditions.
Utilizing Peripheral Blood Stem Cells for Therapeutic Purposes
Peripheral blood stem cell transplantation has been used to treat numerous ailments, such as:
Blood Disorders: PBSC transplantation has been proven to be an effective treatment for various blood-related disorders, including leukaemia, lymphoma, multiple myeloma, and aplastic anaemia. The stem cells transplanted to the patient can help repopulate the blood-producing cells and restore the patient’s immune system, consequently improving their overall health.
Autoimmune disorders: The patient’s immune system is believed to be the cause of many autoimmune diseases including systemic lupus erythematosus, spinal arthritis, connective tissue disease, type 1 diabetes, Sjogren’s disease, rheumatoid arthritis and scleroderma due to it attacking healthy tissues. To help treat the symptoms and improve the quality of life, PBSC stem cell transplants are used as immunomodulators to reset the immune system and alter the levels of certain proteins in the body.
Cancer Treatments: High-dose chemotherapy and/or radiation therapy can effectively eradicate cancer cells in the liver, lungs, kidneys, colon, mesothelioma, and pancreatic cancers. However, these chemotherapy treatments can have harmful side effects and damage the bone marrow and immune system. Peripheral blood stem cell (PBSC) transplantation can help to rebuild the patient’s blood and immune system after their cancer treatments. Discover more about how cancer is identified.
Harvesting Stem Cells from Peripheral Blood: A Guide
Harvesting stem cells from peripheral blood requires a medical procedure known as apheresis. Apheresis is used to collect particular blood cells, like stem cells, while returning the surplus blood components to the donor or patient. Here is a breakdown of the steps involved in extracting stem cells from peripheral blood:
Preparation and Stimulation
- Donor preparation: In order to obtain stem cells from a donor, it may be necessary to give the donor growth factors (such as G-CSF) via injection for a few days before the apheresis procedure. These growth factors stimulate the bone marrow to release stem cells into the bloodstream.
- Preparation of patient: The number of stem cells in the bloodstream of a patient undergoing autologous transplantation may be increased by giving them growth factor injections.
- Collection setup: An apheresis machine separates blood components based on their density, and it is connected to a donor or patient through intravenous (IV) lines.
- Blood collection: The blood drawn from one arm is fed into the apheresis machine, where its stem cells are separated from the other blood components.
- Collection of stem cells: The machine gathers the mandated quantity of stem cells and returns the extraneous blood components, namely red blood cells and plasma, to the donor or patient.
Stem Cell Processing and Storage
- Stem cell separation: The stem cells are filtered out from the other components in the collected blood by a process of centrifugation or filtration.
- Stem cell storage: To ensure their viability and potency for use in transplantation, the stem cells that have been gathered are kept in a cryopreserved (frozen) state.
- Recovery of the patient or the donor: The donor or patient may experience mild side effects, such as fatigue or mild discomfort, following the apheresis procedure. These side effects, while uncomfortable, are generally temporary and will pass in time.
Many different factors such as the purpose of stem cell collection (allogeneic or autologous), the kind of stem cells being harvested, and the donor’s or patient’s health can affect the specifics of the apheresis procedure; however, it is usually shown to be safe and bearable.
Steps Involved in Peripheral Blood Stem Cell Transplantation
Peripheral blood stem cell transplantation (PBSCT) is a complex medical procedure that involves several steps. It’s important to note that the specifics of the process may vary depending on factors such as the type of transplant (allogeneic or autologous) and the underlying medical condition. Here’s a general overview of the steps involved in a peripheral blood stem cell transplantation:
Preparation and Evaluation:
Patient Evaluation: The patient’s medical history, overall health, and specific medical condition are assessed to determine if a stem cell transplant is appropriate.
Donor or Stem Cell Source Selection: Depending on the type of transplant, a suitable donor (allogeneic) or the patient’s own stored stem cells (autologous) are chosen.
Conditioning Therapy: Before the transplant, the patient may undergo a conditioning regimen involving high-dose chemotherapy and/or radiation therapy. This is done to suppress the patient’s immune system and prepare the body for the incoming stem cells.
Stem Cell Infusion:
Stem Cell Infusion: The collected stem cells are thawed if they were cryopreserved and then infused into the patient’s bloodstream through a catheter. The stem cells travel to the bone marrow and start producing new blood cells.
Engraftment and Recovery:
Engraftment: The infused stem cells migrate to the bone marrow and begin producing new blood cells, including red blood cells, white blood cells, and platelets.
Recovery Period: During the recovery period, the patient is closely monitored for potential complications and side effects. Blood cell counts are regularly checked to ensure engraftment is occurring.
- Infection Prevention: Due to the weakened immune system after conditioning therapy, patients are at an increased risk of infections. They may receive antibiotics and other preventive measures.
- Blood Transfusions: Patients may require transfusions of blood components, such as red blood cells and platelets, to manage low blood cell counts.
- Managing Complications:
- Graft-Versus-Host Disease (GVHD): In allogeneic transplants, the donor’s immune cells may recognize the recipient’s tissues as foreign, leading to GVHD. Medications are used to prevent or manage this condition.
- Other Complications: Patients may experience side effects such as nausea, fatigue, mucositis (inflammation of the mucous membranes), and other complications related to the high-dose therapy.
- Long-Term Follow-Up: After successful engraftment, patients continue to be monitored for a period of time to ensure their blood counts stabilize and their overall health improves.
- Continued Care: Depending on the patient’s condition, ongoing medical care and monitoring are essential to manage any potential late effects or complications.
Peripheral blood stem cell transplantation is a complex medical procedure that requires a multidisciplinary team of healthcare professionals, including hematologists, oncologists, nurses, and support staff. The patient’s overall well-being and recovery are the primary goals throughout the transplantation process.
Examining the Difference Between Peripheral Blood Stem Cells and Other Sources
In addition to being used in transplantation, stem cells can also be taken from sources like bone marrow and cord blood from the umbilical cord.
- Umbilical Cord Blood Stem Cells
HSCs (hematopoietic stem cells) are found in abundance in umbilical cord blood and are typically collected at birth. While having a lower risk of graft-versus-host disease (GVHD) relative to other sources, cord blood stem cells have fewer cells than peripheral blood or bone marrow, leading to a slower engraftment process and increased potential for complications. Still, cord blood can be frozen and used for future transplants.
- Bone Marrow Stem Cells
HSCs, or hematopoietic stem cells, are usually collected for transplantation from the bone marrow of a donor, typically through their hip bone. Although very effective, bone marrow transplantation is more intensive and calls for general anaesthesia to be done, unlike the less invasive PBSC collection.
- Umbilical Cord Tissue Stem Cells
Stem cells found in the umbilical cord tissue, specifically in Wharton’s jelly, are dubbed cord tissue stem cells. These cells possess the remarkable ability of self renewal, defining them as mesenchymal stem cells (MSCs). These distinct traits have remarkable regenerative properties.
Cord tissue stem cells possess the unique capacity to transform into many different cell types, including bone, cartilage, fat, and muscle cells. This, coupled with their immunomodulatory and anti-inflammatory properties, makes them a desirable option for researching regenerative medicine and possible treatments for diseases and conditions, such as autoimmune disorders, tissue injuries, and degenerative diseases.
The umbilical cord, which is clamped, cut, and separated from the newborn immediately after their birth, can be used to collect cord tissue stem cells, which like bone marrow stem cells, can be stored and used later in life for potential therapeutic purposes. The process is non-invasive and painless.
Revising Ethics and Exploring Prospects for Peripheral Blood Stem Cells
As further research is conducted, it is anticipated that the potential applications of PBSC transplantation will expand. Nonetheless, there are still obstacles and ethical issues to consider. Current stem cell research is focused on finding new uses for Peripheral Blood and other types of stem cells, as well as enhancing transplantation results and diminishing complications.
Innovative developments in gene editing, immunotherapies, NK Cell treatments, and stem cell therapies will enable more precise, tailored treatment options through the utilization of hematopoietic peripheral blood stem cells.
In order for an allogeneic transplant to be ethically sound, it is essential to obtain informed consent from the donor, take great care to ensure their well-being, avoid any form of coercion, and uphold both the donor and patient’s autonomy and privacy by providing all of the pertinent information regarding potential risks and benefits.
Furthermore, it is essential to ensure access to the procedure is equitably available to diverse populations and that stem cells are responsibly utilized during research and all related activities. Doing so will ensure ethical standards are met and the rights and dignity of those involved are respected.