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The Science of Stem Cells (3 of 3)


Referencing our previous 4 blogs; I thought I would back-up my posts with a few stem cell topic definitions (3 of 3 blogs); these were  extrapolated from various websites and a sector report I have put together as well as excerpts from the International Society for Stem Cell Research.

Are some kinds of stem cells better than others?

  • The field of stem cell research involves the study of these cells for many reasons.  Some scientists are examining stem cells to better understand the process of development to learn how specific cell types and specific tissues and organs are formed.  Some scientists are looking at stem cells to understand what goes wrong in cells to cause various diseases.  For these purposes, valuable information can be gained by studying any of the stem cell types that are currently available,
  • The most publicized use for stem cells, however, is their ability to form different types of cells that can be used to restore or replace damaged tissue in patients with disease or injury.  From studies using mice, it was found that mouse embryonic stem cells could contribute to every tissue in the adult mouse.  It is believed that human embryonic stem cells have this property, and are called pluripotent stem cells.  Scientists now need to compare human embryonic stem cell lines for their potential in tissue repair to that which can be accomplished from adult stem cells,
  • Currently, it is not “totally” clear whether stem cells from adult tissues or umbilical cord blood are pluripotent.  The comparison of human embryonic stem cells to adult stem cells is currently a very active area in research, and one that will hopefully lead to cures for tissue degenerative diseases in the future.

What are the obstacles that must be overcome before the potential uses of stem cells will be realized?

  • One of the first obstacles that must be overcome is the difficulty in identifying stem cells from adult tissues, which contain numerous mixtures of various cells.  The process of identifying and growing the right kind of stem cell, usually a very rare cell in the adult tissue, involves painstaking research,
  • Second, once stem cells are identified and isolated, the right conditions must be developed to cause these cells to differentiate into the specialized cells.  This too will require a great deal of experimentation.  In general, embryonic and fetal stem cells are believed to be more versatile than adult stem cells.  However, scientists are still working on developing proper conditions to differentiate embryonic stem cells into specialized cells.  As embryonic stem cells grow very fast, scientists must be very careful in fully differentiating them into specialized cells.  Otherwise, any remaining embryonic stem cells can grow uncontrolled and form tumors,
  • Assuming that the above obstacles can be overcome, new issues arise when the specialized cells (grown from stem cells) are implanted into a person.  The cells must be integrated into the patient’s own tissues and organs and “learn” to function in concert with the body’s natural cells.  Cardiac cells that beat in a cell culture, for example, may not beat in rhythm with a patient’s own heart cells.  And neurons injected into a damaged brain must become “wired into” the brain’s intricate network of cells and their connections in order to work properly,
  • Yet another challenge is the phenomenon of tissue rejection.  Just as in organ transplants, the body’s immune cells will recognize transplanted cells as “foreign,” setting off an immune reaction that could cause the transplant to fail and possibly endanger the patient.  Cell recipients would have to take drugs to temporarily suppress their immune systems, which in itself could be dangerous.

Bottom Line:  Research on stem cells and their applications to treat various diseases is still at a preliminary stage.  However, results from clinical trials are few even after some holds and failures.  But, a few  are  promising and many researchers believe that it is only a matter of time before  results can be achieved with human stem cells.