REGENERATIVE MEDICINE WITH EMBRYONIC CELLS
Recents advances in embryonic stem cell research open a new field with very important clinical applications in regenerative medicine using stem cells as replacement therapies, for neuro-degenerative diseases, diabetes and treatment of the cancer.
Regenerative medicine is a term used in the production and transplantation of stem cells to repair or regenerate the damage organs of our body
How does it work?
Using the so-called stem cells
What are the stem cells?
They are cells with the ability to undergo both self-renewal and differentiation into cells of the body.
Based on their derivation are classified in embryonic, fetal and adult stem cells, and based on their potentiality to be transformed to specific body cell in totipotential, multipotential, pluripotential and unipotential.
Where can we get them?
They are several sources of stem cells with the capability to give rise to pluripotent cell lines:
1.- From pre-implantation embryos, in the inner cell mass of the blastocyst- stage (they are called embryonic stem cells)
2.- From fetal cells
3.- From adult stem cells
The embryonic stem cells can proliferate indefinitely and have the capability to differentiate in any kind tissue, even the trofoblastic cells .They can differentiate into derivatives of all three embryonic layers when transferred.
The fetal and adult stem cells are predetermined cells which can differentiate into a limited cells specific for a given tissue, but recent research seems that their potentiality is higher to that believed, so for instances bone marrow cells after transplantation contribute to the regeneration of hematopoietic system and can also contribute to repair damage organs such as brain, liver, pancreas, muscle. This special capacity of this adult cells is called "plasticity" meaning that they can differentiate into cells different from the original tissue. These cells have a potential to differentiate into neuronal cell, muscle cell, liver cell, epidermal cell and also epithelial cell lineages
Technology:
Undifferentiated human embryonic stem cells can be culture indefinitely and maintain the capability to form almost every cell in the human body. Different protocols have been used in order to guide stem cells into specific cell lineage such as:insulin- secreting cells ( ß cells of pancreas),.hematopietic precursors, ,neural precursors which can further generate functional neurons, astrocytes and oligodendrocytes, cardiomyocytes and various other cell types
Some possible applications of stem cells:
Recent advances in embryonic and adult stem cell research open a new field with very important clinical applications in regenerative medicine using stem.
The recent identification of adult cells as well that the embryonic stem cells that can grow and differentiate in any tissue, has raised the possibility of using them for organ repair ("so-called regenerative medicine"). Herewith we include some possible applications of stem cells and hopes for this novel therapy:
1-transplantation of exogenous cells into damage myocardium, in cases of myocardial infarction and heart failure, so-called "cellular cardiomyoplasty",
2-transplantation of pancreatic islet cells (insulin secreting cells) in the treatment of diabetes mellitus
3-transplantation of embryonic dopamine neurons into Parkinson's disease
4-bone and cartilage repair
5-skeletal muscle repair as in the case of muscular dystrophy
6-ischemic brain injury
7-autoimmune encephalomyelitis
Some other applications and perpectives are: brain tumors, neuro-degenerative diseases and hepatic malignancies .
Limitations of the use of stem cells
The use of stem cells have some limitations such as:
-technical barriers have to overcome before clinical trials can be considered
controlling cell growth and differentiation
-more research is needed to overcome some obstacles and to determine which type of stem cell constitute the best solution for any particular disease and patient-, The controversy between adult versus embryonic stem cells still persists
-a number of ethical and legal questions have to be overcome. The ethical problem is debated and different attitudes, towards using existing human embryos or creating new human embryos for research, exists from country to country in Europe. Another problem is the commercialization of embryos and their derivatives after a therapeutic cloning.
-finally we have to be careful with the excessive perpectives that has been generated with this biological advances , and not to give to the patients and families false hopes, as Science magazine in 1999 declared "embryonic stem cells have been touted as a cure for just about everything that ails us" regenerative medicine opens important possibilities , but medical progress and gene therapy will be slow.
Dr. Jaume Antich
