Stem cells are those unspecialized cells whose daughter cells may become different specialized cells for example stem cells may develop into blood cells.
Stem cells have found important roles in replacing tissues which are damaged as well as providing extra-cellular factors that can promote replacement of used items or materials.
Umbilical cord blood cells:
Umbilical cord is a tube connecting fetus to placenta. (Fetus refers to an unborn offspring and placenta refers to the organ in the womb or uterus of the pregnant woman.) Umbilical cord blood cells have found uses in a large number of trials such as paraplegia, amyotropic lateral sclerosis, ataxia, cerebrovascular disease, motor neuron disease and certain other indications.
Beneficial part is that it does not causes severe immunological responses. (Paraplegia refers to inability to move lower body, Amyotropic lateral sclerosis refers to a disease of nervous system in which the muscles become weak, Ataxia refers to lack of muscle control, Cerebrovascular refers to the brain’s blood vessels).
They have also been found useful for blood and immune disorders and cancer.
Placenta derived stem cells:
They have found similar uses as that of umbilical cord blood cells. Their use in critical limb ischemia is under process. (Ischemia refers to lack of blood).
Bone marrow stem cells:
Bone marrow stem cells have found uses in blood and immune disorders as well as cancers.
Mesenchymal stem cells (MSC):
Mesenchyme is the cell mass of the embryo that develops into bone, cartilage, connective tissue, blood and the lymphatic system. MSCs are either used for or under trial for Bone/Cartilage disease, Heart diseases, cancer, diabetes, neurodegenerative disorders, gastrointestinal disease and immune rejection/ Autoimmunity.
Hematopoietic stem cells, MSCs and bone marrow aspirates have found uses in heart muscle tissue repair. Umbilical cord blood cells have found uses in improving cardiac function in myocardial infarction. (Aspirate refers to removal of liquid or gas by suction.)
Umbilical cord blood cells have been found useful for the formation of neurons in vitro but little efficiency have been found in vivo neuron formation. Mobilized peripheral blood cells (CD34+) have been found useful in the chronic spinal cord injury.
MSCs have found use in the treatment of multiple sclerosis and ALS.(Sclerosis refers to hardening and thickening of bdy tissue)
More recent therapeutic strategy for Multiple sclerosis is done by immunosuppression followed by transplantation of autologous CD34+ hematopoietic stem cells (HSCs).Improvements are observed in dermal fibrosis and pulmonary dysfunction in the patients of systemic sclerosis with HSC therapy for upto 8 years.
HSC therapy is under trial for rheumatoid arthritis and juvenile idiopathic arthritis.
Adipose stem cells (ASCs):
Adipose refers to the tissue containing fat. These tissues are plentiful and easy to access. They have been found useful in the soft tissue repair such as tissue damaged by radiation and fistulas in Crohn’s disease.
(Fistula refers to an abnormal opening or passage between two organs or between an organ and the skin and Crohn’s disease
refers to inflmmatory bowel disease)
They have found equivalent use for myocardial infarction as that of MSCs.
Endothelial stem cells:
Endothelial refers to internal layer of the certain body cavities. Endothelial stem cells can easily be obtained from umbilical cord blood, bone marrow and adipose tissue. They have been found efficient in the stimulation of angiogenesis.
(angiogenesis refers to the formation of new blood vessels).
Pancreatic beta-islet cells:
The use of embryonic stem cell derived beta Islets in special subcutaneous capsules that induce minimal fibrosis may evolve into clinical trials shortly.
Neural stem cells (NSCs):
Neural refers to that of nerves. They may be obtained from fetal, neonatal or adult brain. They differentiate to form neurons. Clinical trials are under process for the use of fetal neural stem cells for the lysosomal storage disease.
Clinical trials for the use of NSCs for the diseases of ALS, stroke, Advanced Parkinson’s disease and Chronic spinal cord injury are under process.
Limbal stem cells:
Limbus refers to the edge of various organs or body parts for example the area in the eyeball where the cornea and sclera meet. Corneal disease is found to be treated by the use of corneal epithelial stem cells which are located at the basal layer of the limbus epithelium. Corneal disease is the second most common cause of blindness and corneal epithelial cells, which are lost or damaged, are replaced with corneal epithelial stem cells.
Regeneration of skeletal muscles in cases of muscular dystrophy depends on myogenic progenitors. (Myogenic progenitors refer to the ancestors develop from muscle cells.)
Liver based metabolic disorders are now most successfully treated by hepatocyte transplantation. (Hepatocyte refers to the cell of the liver).
Pluripotent stem cells:
Human motor neuron progenitor cells derived from human embryonic stem cells have been found useful in Spinal muscular atrophy. Similarly, Retinal Pigment Epithelium derived from human embryonic stem cells have been found useful in Age-related Macular Degeneration.
References and Further Reading:
Trounson, A. et al. (2011). Clinical trials for stem cell therapies. BMC Medicine, 9(52).