STEM CELL THERAPY

INTRODUCTION
Stem cells are the raw material from which all of the body’s mature, differentiated cells are made.  Stem cells give rise to brain cells, nerve cells, heart cells, pancreatic cells, etc.
Stem cells are regenerative cells that lead to the creation of new cells. The cells can also help existing cells in the body to perform better. The types of adult stem cells used are from the patient's own blood, bone marrow, and fat. Stem cell therapy rests on the fundamental principle that cell phenotype is dependent on a combination of two elements: the starting cell population and the environment in which the cells are placed. It is this combination that must be characterized to derive effective cell therapy.

Special Characteristics of Stem Cells?

- They have the potential to replace cell tissue that has been damaged or destroyed by severe illnesses.
- They can replicate themselves over and over for a very long time.

Potential therapeutic uses of stem cells

Stem cells are seen as tools for replacing, repairing, regenerating, and rejuvenating dead, degenerating, or injured cells and tissues.

Replacement: Certain diseases such as Parkinson's or Type I diabetes are caused by progressive degeneration of one or a few cell types. In such cases, stem cells used as replacement cells can offer 'lifelong treatment'.

Repair: By isolating stem cells in a laboratory, scientists theoretically could grow new heart cells to repair damage from heart attacks, new liver cells to treat hepatitis, and new red blood and stromal cells for cancer patients after ablative radiotherapy.

Regeneration and rejuvenation: Stem cells are also capable of interacting with the organism in which they are implanted. They can secrete factors that renew or regenerate the surrounding tissues. They might thus be used to renew biological functions, such as the immune system, or act trophically to support and rejuvenate host cells. This has been demonstrated in mouse models of stroke and Parkinson's disease.

Uses: A large number of conditions are generally treated with stem cell therapy. A few of them are:

• ALS
• Autism
• Cerebral Palsy
• Diabetes Type II
• Multiple Sclerosis
• Parkinson's disease
• Rheumatoid Arthritis
• Post Stroke Syndrome
• Orthopedic conditions
• Peripheral Vascular Disease
• Heart failure.

Stem cell transplantation is a big step forward in medicine as it can be implemented to cure inherited severe blood cell disorders, immune system deficiency, many other inherited disorders and bone marrow failure.

Kinds of Stem Cells

Embryonic stem cells
Embryonic (also called “pluripotent”)    stem cells are capable of developing into all the cell types of the body.  Adult stem cells are less versatile and more difficult to identify, isolate, and purify. Researchers extract stem cells from a 5-7 days old blastocyst. Stem cells can divide in culture to form more of their own kind, thereby creating a stem cell line. The research aims to induce these cells to generate healthy tissue needed by patients.

Two Sources of Embryonic Stem Cells

a. Excess fertilized eggs from IVF (in-vitro fertilization) clinics
Tens of thousands of frozen embryos are routinely destroyed when couples finish their treatment. These surplus embryos  can be used to produce stem cells. Regenerative medical research aims to develop these cells into new, healthy tissue to heal severe illnesses.

b. Somatic Cell Nuclear Transfer

The nucleus of a donated egg is removed and replaced  with the nucleus of a mature, "somatic cell" (a skin cell, for example). >No sperm is involved in this process, and no embryo is created to be implanted in a woman’s womb. The resulting stem cells can potentially develop into specialized cells that are useful for treating severe illnesses

Embryonic stem cells are pluripotent. They have no natural environment; they exist only in vitro. When implanted, they interact minimally with the surrounding tissues and form tumors called teratomas that are reminiscent of the embryonic bodies formed in culture. Embryonic stem cells are usually derived from a blastocyst embryo, but they can also result from retro-differentiation of tissue-restricted stem cells. Tissue-restricted stem cells can be harvested from organs, cord blood, or the bone marrow, or they can be obtained by differentiation of embryonic stem cells or trans-differentiation of other tissue-restricted stem cells.

Adult stem cells

Adult stem cells are multipotent cells that self-renew and persist in the body throughout life. These are quiescent cells living in an essentially stable environment.

Fetal stem cells

Fetal stem cells live in an evolving environment, to which they must constantly adapt, and their potency varies over time as the brain or other organs develop. They are probably the most interesting candidates for product development.

Cord Stem Cells:

Cord Stem Cells are responsible for creating the entire human body.

These cord stem cells are the original cells produced in the human body. They divide and multiply within the human body, and the first cord stem cells originate within the developing embryo. Many of the so-called "incurable diseases" can be caused by the degeneration of specific cell types in the body.

Umbilical cord stem cells:

Umbilical cord stem cells are harvested from the umbilical cord of a full term live birth, not from an aborted fetus. This type of cord stem cell therapy involves the introduction of healthy new cord stem cells into the body to repair and replace damaged or lost cells.

Types of Cord Stem Cell Therapies:

Whole Cord Blood stem cell therapy: It involves the use of stem cells derived from full term births which were donated with informed consent. When permission is given by the parents, research goes forward and the umbilical cord is sent to the laboratory to be tested for many diseases and the different stem cells are harvested. Unlike embryonic or fetal stem cells, cord stem cells are programmed to rapidly support the development and growth of all body systems, and are pluripotent.

Purified and Potentiated Cord Blood Stem Cell Therapy: It involves the use of proprietary protocols to remove the white and red blood cells from cord blood leaving only stem cells. This process negates the risk of Graft versus Host Disease and the need for cross matching. Embryonic Cord Stem Cells Therapy- involves the use of cells extracted from a five day old in vitro fertilized embryo. The viability of this cell type is limited, because only small numbers of cells can be derived from an embryo, and thus, they need to be expanded in the lab, currently with an animal intermediary, which limits their use in humans.

Fetal Cord Stem Cell Therapy: It involves the use of human fetuses aborted between the first and third months. Retrieval of fetal stem cells in adequate numbers is limited.

Adult Stem Cell Therapy: It involves the use of stem cells derived from bone marrow, peripheral blood, and some tissues. Adult stem cells are understood to be 1/1000 as powerful as cord stem cells, since they have endured age stresses, toxicity, and often, disease. Their use is limited by the risk of graft versus host disease.

Conclusions

Stem Cell Therapy is an emerging therapy which holds lot of promises. Although, it has been used for 10 years or so but there is no concrete data available to support the efficacy of the treatment in childhood neuro-developmental disorders. A large number of parents have been trying stem cell therapy as adjuvant to standard therapies and reportedly happy. The major issues are:

• Which type of cell to implant for which indication?
• The question of whether the in vivo models used are relevant.
• Possibility of tumor formation.
• How to preserve and administer the stem cells successfully.