Researchers and biotech executives foresee the day when the effects of many catastrophic diseases can be reversed. The damaged brains of Alzheimer's disease patients may be restored. Severed spinal cords may be rejoined. Damaged organs may be rebuilt. Stem cells provide hope that this dream will become a reality.
~ George Wolff
~ George Wolff
A stem cell is akin to a blank sheet of paper - you can use it to write anything you want. Similarly, a stem cell is a blank, all-purpose, cell that is found in multicellular organisms and these cells undergo mitosis and go on to differentiate and take diverse forms, each form having complex biological functions of their own.
These differentiated cell types undergo further cell division to multiply and constitute various different types of specialized cells such as dermal cells, muscle cells, neural cells, etc. These different types of cells go on to form the various organs and physiological structures inside the body. In short, stem cells are among the most basic raw materials that make up the recipe for multicellular organism biology.
Based upon their primary functions post mitosis and differentiation, stem cells can be classified under two broad categories - constructive stem cells and restorative stem cells. As the name suggests, constructive stem cells are specialized cells that multiply and combine to form specialized organs while restorative stem cells are those that carry out the biological reparation process wherein the worn out tissues are repaired or replaced by new ones.
At the embryonic stage, the primary and sole function of stem cells are that of construction of organs by differentiating into specialized cells. In adults, the major function of stem cells is reparation and restoration of worn out tissues, as all organs are formed in a fully grown organism and further construction is not needed. Fetal stem cells are blank cells that come somewhere between embryonic stem cells and adult stem cells.
An Overview of Fetal Stem Cells
As the name suggests, these stem cells are the pre-differentiation elementary cells that are found in the fetal organs. There are, broadly, two types of fetal stem cells - pluripotent or hematopoietic. Pluripotent stem cells have the ability to differentiate to form the inner tissue lining of the stomach and gastrointestinal tract, muscles, bones, urogenital organs, organs of the nervous system and the epidermal layer. Hematopoietic stem cells differentiate and specialize to become various different types of blood cells. The pluripotent stem cells are found in the various organs of a fetus while the hematopoietic stem cells are found in the umbilical cord blood.
A bulk of the cases involving fetal stem cell therapy use the stem cells found in the cord blood as this can be easily acquired without causing any harm to the fetus or embryo. Also, compared to adult stem cells, primitive stem cells from fetuses are a lot more versatile for the purpose of stem cell transplants and the body is less likely to reject these. Also, most adult stem cells are multipotent, meaning the number of lineages from which cells can emerge is different from source tissue cells. Stem cells derived from fetuses are more versatile in this aspect.
Coming to the issue to treatment and disease cure using stem cells, since these cells are blank and can be made to become any type of cell required, they are extremely useful to treat terminal and degenerative diseases such as Parkinson's diseases, Alzheimer's disease, cancers, spinal cord injuries, musculoskeletal degeneration. The damaged tissues can be replaced with appropriate stem cells that can undergo mitosis, and specialize to repair the affected tissues and cellular architectures.
However, the issue of ethics in human stem cell research is a major bone of contention and the extraction and use of embryonic stem cells is actively condemned by a lot of people who maintain that an embryo is potential human life and, as such, should be treated with the same regard as that of a living human being.
In the light of this situation, fetal stem cells seem to hold the key to unlock a lot of lifesaving medical breakthroughs, as these stem cells (especially the ones in the cord blood) can be extracted without harming the fetus. Also, being more versatile than adult stem cells and being less likely to be rejected on transplant, this class of stem cells do get a greater medical edge. Also, these stem cells can be cultured and stored indefinitely in laboratories.