Stem cell Therapy

Stem cells are the cells from which all other cells with specialized functions are produced under accurate conditions either in the body or in a laboratory. Such stem cells divide repeatedly to form daughter cells which become either new stem cells or differentiate into specialized cells with specific functions, like blood cells, brain cells, heart muscle cells or bone cells.
Only stem cell has the natural capability to produce new cell types.

Stem cells may be derived from different sources. They may be
Embryonic stem cells derived from a three to five days old embryo called blastocyst with 150 cells.
These are pluripotent stem cells, which can divide to form more stem cells or differentiate into any other type of cells in the body.
Such a tendency of embryonic stem cells helps in the regeneration or repair of the diseased tissue and organs.
Adult stem cells found in adult tissues, such as the brain, bone marrow, blood vessels, skeletal muscle, skin, teeth, gut, liver and fat. These stem cells occur in small numbers and have limited capacity to give rise to various cells of the body.
Stem cells of amniotic fluid are used in the treatment either during gestation or after birth.
Induced pluripotent stem cells (iPS cells) are cells which are reprogrammed by scientists to perform like stem cells, in regenerative medicine.

Stem cell therapy is a regenerative medicine, used to treat or prevent a disease or condition, or to repair diseased, dysfunctional or injured tissue using stem cells or their derivatives.

Stem cell therapy using tissue stem cells has been in use since the 1970s. Then, to replace a patient’s diseased blood system for life, bone marrow transplants were widely used.
Since the 1980s, skin stem cells have been used to grow skin grafts for patients with severe burns on very large areas of the body.

Ten stem cell therapies have been approved so far around the world on or after January 2016, but the only widely used stem cell-based therapy is bone marrow transplantation.
The most widely used Bone marrow transplant is used to treat autoimmune diseases and cancers such as leukemia and lymphoma.

Transplanted stem cells, like all transplanted organs, are recognized as foreign by the immune system and will be rejected. Sometimes, the donor’s immune cells attack the patient’s tissues causing infection or graft-versus-host disease (or GVHD) during the treatment.  So, the person should be on powerful immunosuppressive drugs during stem cell therapy.

Another stem-cell therapy, which was conditionally approved in Canada in 2012 to control the acute graft-vs-host disease in children who are unresponsive to steroids is Prochymal.
At present, Cord blood stem cells are being used in the therapy. They are collected from the umbilical cord of a baby after birth, frozen in cell banks and are used to treat children with cancerous blood disorders such as leukemia, and genetic blood diseases like Fanconi anaemia.
Stem cells obtained from one umbilical cord are less in number. So, they cannot be used to treat adults.
In the case of treatment of adults, cord blood stem cells obtained from two umbilical cords are used.
Although cord stem cells have the capacity to produce other types of specialized cells not related to the blood, it is not yet confirmed by researchers. So far, only blood diseases can be treated with cord blood stem cells.

Applications

Stem-cell therapy is used to treat a wide range of diseases like

Autoimmune diseases
Blindness and vision impairment---stem-cell-based treatment is used to repair damaged cornea (the surface of the eye) to restore vision.
Cochlear hair cell regrowth--- embryonic stem cells are used to regrow cochlear hair cells of inner ear and thus this therapy helps in hearing sounds.
Cancers
Infertility- human embryonic stem cells also used to treat infertility.
Neurodegeneration--- This therapy is used to cure disease and conditions like Parkinson's, amyotrophic lateral sclerosis, and Alzheimer's disease, multiple sclerosis, stroke and traumatic brain injury leading to cell death, spinal cord injury.  This therapy replaces neurons damaged by spinal cord injury, stroke, Alzheimer’s disease, Parkinson’s disease or other neurological problems
Orthopedics---- orthopedic applications are found in bone and muscle trauma, cartilage repair, osteoarthritis, intervertebral disc surgery, rotator cuff surgery, and musculoskeletal disorders.
Regrowth of teeth--- Stem cell therapy can be used to grow live teeth in people. Stem cells taken from the patient are used to develop a tooth bud in the lab and when it is implanted in the gums, will give rise to a new tooth. It will fuse with the jawbone and release chemicals that help nerves and blood vessels to connect with it.
Severe heart disease----This therapy helps in the generation of heart muscle cells that could repair damage after a heart attack, Stimulates growth of new blood vessels in the damaged heart tissue, Secretion of growth factors and Blood-cell formation.
Type 1 diabetes --- People with Type 1 diabetes lose the function of insulin-producing beta cells within the pancreas. This therapy is used to treat people with diabetes by developing pancreatic beta cells which secrete insulin.
Wound healing--- This therapy is used to stimulate the growth of human tissues in the wounds where wounded tissue will be replaced by scar tissue. Because of the general healing capabilities of stem cells, they have gained interest for the treatment of cutaneous wounds, such as skin cancer.
HIV/AIDS-- Recently, scientists have been investigating an alternative approach to treat HIV-1/AIDS, by developing a disease-resistant immune system through transplantation of autologous, gene-modified (HIV-1-resistant) hematopoietic stem cells.

Controversy

The use of stem cells in medical research has been controversial because in the late 1990s, scientists used stem cells derived from human embryos by destroying the embryos.
President George W. Bush banned funding for human stem cell research in 2001 as he had strong, pro-life religious views.
However, by 2006, scientists started stem cell therapy using pluripotent stem cells instead of embryonic stem cells.
This technique and other recent advances in stem cell technology, will revolutionize therapeutic norms and introduce a new standard of personalized treatment.

Disadvantages

Person’s immune system will recognize stem cells isolated from IVF embryos as foreign and reject the tissue. But stem cells generated through SCNT or iPS cell technology, may escape the notice of the immune system as they have a perfect genetic match.

Stem cell therapy requires immunosuppression because the patient's immune system may target the stem cells recognizing them as foreign cells. To avoid the immunosuppression, stem cells from the same patient who is under treatment can be used.

Pluripotency in certain stem cells may generate tissues other than required types. Instead of multipotency, some stem cells form tumors.

Side Effects

Mouth and throat pain, Nausea and vomiting, Bacterial and fungal infections, Bleeding, Interstitial pneumonitis and other lung problems, Graft-versus-host disease, blocking of tiny veins and other blood vessels inside the liver (Hepatic veno-occlusive disease), infertility, second cancers,

The medicines used in transplants can damage the body’s organs, such as the heart, lungs, kidneys, liver, bones, joints, and nervous system.

Each group of stem cells must be grown in an identical, repeatable, sterile environment and good manufacturing practice (GMP) conditions, so that each batch of cells will have the same properties, and each person will receive an equivalent stem cell therapy treatment.