This article details stem cell types and collection methods, focusing on hematopoietic stem cells and their clinical applications, while highlighting recent innovations and ethical considerations in stem cell research.

With the ability to differentiate into a wide variety of other body cell types, stem cells are cells. For the body, they act as a repairing mechanism. There are 4 types of stem cells:

• Hematopoietic stem cells
• Mesenchymal stem cells (MSCs)
• Neural stem cells(NSCs)
• Epithelial stem cells

Hematopoietic stem cells (HSCs) are capable of self-renewal with the formation of all lines of blood cells. These cells are used to treat haematological malignancies, congenital and acquired aplasia and after intense radiation and chemotherapy.

MSCs are mainly used for tissue regeneration. Neural stem cells are used for plasticity, ageing, disease and regeneration of the nervous system.

Stem cell therapy

Aims - Stem cells are the only cells in your body that make different cell types, like blood, bone and muscle cells. They also repair damaged tissue. So to cure disease stem cells are used.

Objectives - Stem cell therapy is an indirect method to eliminate or compensate for genetic deficiency by replacing or overriding existing disease cells.

Method - Here we discussed hematopoietic stem cells. HSC collection is done by mainly 3 methods

• Umbilical cord
• Bone marrow
• Peripheral blood

For umbilical cord collection, the umbilical cord is clamped and separated from the infant in a manner that does not interfere with routine delivery practice. Bone marrow is a surgical procedure obtaining marrow from the posterior iliac crest.

Peripheral blood stem cells can be collected by apheresis instrument. The operator determines the number of cycles, cycle volume, flow rate, RBc of set and interface set point to optimise the collection.

Discussion 

Multipotent primordial cells called hematopoietic stem cells (HSCs) can differentiate into all subtypes of blood cells, including lymphoid and myeloid lineage cells.  Among the organs that contain HSCs are peripheral blood (PB), bone marrow (BM), and umbilical cord blood (UCB).

The production of all blood cell lineages occurs through the functional maturation of a rare population of multipotent HSCs, which can proliferate through differentiation and self-renewal. Therefore, it is critical to comprehend the molecular mechanisms governing HSC/progenitor cell self-renewal and cell fate determination to develop clinical applications tailored to the specific kind and severity of disease.

The whole hematopoietic process can be started with a tiny number of HSCs. Diagram illustrating the process by which stem cells differentiate into different types of cells.

In hematopoietic stem cell transplant, there are some criteria to fulfil. Donor suitability is to be checked and evaluated for fitness to the procedure. After the mobilisation of hematopoietic cells with stimulating factor G-CSF, the stem cell harvesting procedure started.

The harvesting procedure should begin when the leucocyte counts 5 million /L. Primitive and committed progenitor cells express CD 34 antigen on their surface. It is ideal to start the procedure when CD34+. The count increases by about 10 cells/microlitre.

In my career, I have performed approximately 40 hematopoietic stem cell procedures for cancer patients out of this only 4 pt graft rejections occur otherwise all pt were cured. Autologous and allogenic both types of procedure performed according to disease.- Author

HLA matching was performed before the process for allogeneic hematopoietic stem cell transplantation.

Innovations

1. Scientists have used genetic reprogramming to turn ordinary adult cells into stem cells. Researchers can make adult cells behave like embryonic stem cells by changing their DNA. The term "induced pluripotent stem cells" (iPSCs) refers to these cells.  These cells are used to produce cancer vaccines. Gene therapy is also used to treat or replace diseased parts.
2. The fundamental structural and functional component of heredity is the gene.  These are the specific sequences e of bases that encode how to make proteins. alteration in these units leads to the production of proteins which are unable to carry out their normal function, resulting in genetic disorders. So by replacing this altered gene, we can cure disease.
3. In Gene therapy, different types of viruses are used as vectors. The main viruses are adeno and retroviruses. Adoptive immunotherapy is another method to Help the immune system to fight cancer.
4. In this, a cancer patient's T cells are collected and grown in a laboratory to increase the number of T cells that can kill a person's cancer cells. These cancer-specific T cells are given back to patients to help the immune system fight the cancer.

Application

Stem cells are used in:

• Congenital immune deficiency
• Chronic granulomatous disease
• Aplasia
• Hemoglobinopathies
• Lymphoma
• Leukaemia
• Solid tumours
• Autoimmune disorder
• Regenerative disorder cardiac tissue repairing
• Peripheral vascular disease
• Bone fracture
• Muscle/tendon repair

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article:  Dr Parul Prajapati is MD (IHBT), Working as an Immunohematologist and blood transfusions at U N Mehta Institute of Cardiology and Research Centre Ahmedabad, Vastral, Gujarat.