Stem cells are ubiquitous, pluripotent and primitive cells having capacity to self renew and multilineage differentiation.
- Embryonic stem cells: originate from the inner cell mass of the blastocyst.
- Adult stem cells: originate during ontogeny and maintain tissue homeostasis.
- Induced pluripotent stem cells: originate from somatic differentiated cells after transduction.
- Resident stem cells: present in adult tissues like bone marrow, GI tract, hepatocytes, etc. for functioning to replace the cells during injuries.
- Cultured stem cells: derived from embryonic stem cells and adult somatic stem cells having tremendous tissue specificity.
- Isolated stem cells: obtained from the organs or tissues and identified by specific cell surface markers using Flow Cytometry. Eg. Hematopoietic stem cells.
Mesenchymal stem cells are the most popular type of stem cells. These are preferentially derived from umbilical cord tissue. Fetal stem cells comparatively have higher expansion capacity, higher immunosuppressive capabilities and lower level of immunogenicity than the placenta derived Stem Cells. Stem cells derived from umbilical cord are used to treat autism, cartilage injuries, cerebral palsy and Acute Respiratory Distress Syndrome induced by Covid – 19 used to treat the same. Pulmonary function and symptoms with COVID – 19 pneumonia showed signs of improvement within 2 days after stem cell transplantation.
Blood is collected outside the uterus when the placenta is delivered so that all the blood of the umbilical cord and some from the placenta can be drained into a container. Then it is cryogenically preserved to keep it viable for decades.
Stem cell therapy
Stem cells are grown in the lab and manipulated to specialize into specific type of cells like cardiac muscle cells, nerve cells, etc. These specialized cells are implanted into a person to repair the injured cells in the body.
In stem cell transplantation, stem cells replace cells damaged by blood related diseases or radiation therapy or chemotherapy to counter the effect of leukaemia, lymphoma, neuroblastoma and multiple myeloma.
Concept of stem cell replacement of cardiomyocytes can be used for cardiomyopathies. Stem cells can also be used to treat neurodegenerative diseases like Parkinson disease, Alzheimer’s disease and spinal cord injuries.