Stem Cells and Regenerative Medicine

The Human body is made up from millions and millions of tiny parts called CELLS.

Cell Simplified Structure

This is a very simplified diagram of a typical cell.

Every person starts off from one cell, the Fertilized Egg Cell.  See the page Egg, Sperm and Mitochondria.

The Fertilized Egg divides to form two cells, then they divide to form four cells, then eight, then sixteen and so on. Very quickly the Fertilized Egg becomes a large cluster of cells.

Every cell contains the information needed to form different parts of the body. That information is in the Nuclear DNA  of the cell.

The cells of this very early embryo will keep dividing to produce more cells.  In the early stage, any cell could produce any part of the body.  As the embryo develops, different cells specialise in function.

  •  Some Embryo cells will turn into Blood Cells.
  • Some Embryo cells will turn into Liver Cells.
  • Some Embryo Cells will turn into Bone Cells.
  • Some Embryo Cells will turn into Muslce Cells
  • Some Embryo Cells will turn into Brain and other Nerve Cells.

and so on

Embryonic Pluripotent Stem Cells are these cells in the early Embryo that have not yet “decided” which specialised organ to form, but are capable of turning into any of them.


Once a cell has specialized, it cannot turn into another kind of tissue.  A blood cell can’t become a nerve cell.

Fertilized Egg Stem Cells and Tissues

The mechanism that controls how a stem cell “decides” what to become, and how it grows into the eventual organ, is very complicated.  Researchers are still investigating many parts of the mechanism.  Things which affect the way a stem cell develops include chemical signals from other cells around it and the physical environment, such as having a solid structure to “cling to”.

Once the tissues have been formed in a Human Body, they are not very good at repairing or regenerating themselves.

The Liver is about the only major organ that can regenerate itself after major damage.  Even that isn’t particularly good.

Researchers are looking at ways to take Stem Cells and use them to regenerate or repair parts of the Human Body.

Obstacles they are facing are:

  • How to obtain the stem cells
  • Implanting stem cells can lead to an immune response and they get rejected.
  • The stem cells need to be placed in the right place, in the right way to be useful.
  • The stem cells need to be prompted or controlled into regenerating or repairing the right tissue.
  • The stem cells need to be controlled so they don’t spread and become cancerous.

Using Human stem cells from embryos has obvious ethical issues.

Researchers are looking for other ways to find or produce stem cells. Examples are extracting them from the Umbilical Cord and Cord Blood,  Amniotic Fluid, the Placenta and finding a type of cell in Adult skin that can be treated to turn it into a stem cell.

Diagram of human pregnancy

Researchers are developing Stem Cells for clinical research from tissue normally thrown away at birth, such as cells in Amniotic Fluid, the Placenta and the Um bilical Cord.

They are also trying to find sources of Stem Cells from inside the adult human body.

When researchers “reprogram” a cell to turn it into a useful stem cell,  they call it an “induced” stem cell.   They have “induced” or converted it into a stem cell.

A “pluripotent” stem cell is a kind of stem cell with the ability to turn into many different types of cell, such as blood, bone, nerve, muscle or retina.

That is why a lot of news items mention researchers working with “induced plouripotent” stem cells.

As of August 2015 Stem Cell research is almost all in cell cultures and animals.  Scientists are studying how to produce stem cells that can be treated and implanted to try and repair the Retinal Ganglion Cells of the Human Eye.

They are also studying how to create stem cells to repair the PhotoRecemptor layer of the eye.  This is to treat Retinitis Pigmentosa, not LHON, but the research into basic techniques of stem cell treatment will be useful to LHON patients.

The Retina and the Eye in general is a popular choice for stem cell therapy research.  For many years doctors believed that a damaged Retina and a damaged optic Nerve could never be repaired.

Recent research on animals shows that replacing dead or damaged Retinal Ganglion Cells may be possible, and they may even grow new fibers to repair the Optic Nerve.  This is the hope for the future.

Regenerative Medicine means finding a way to help the body heal itself, repairing or replacing a damaged organ.  Human Adult body parts are not very good at doing this.  Even if they heal, they usually form scars instead of building working replacement tissue.  So a big part of Regenerative Medicine is trying to find ways to get around this.  Stem Cell Research is looking for ways that Stem Cells can trigger more useful healing, or directly grow a working replacement body part.

Stem Cells and Regenerative Medicine have become big news in the popular science press.  That is because of the huge potential promised to repair damaged or diseased tissue in the future.

Sadly many “clinics” have sprung up offering unproven, even dangerous or fake “stem cell” treatments.

Desperate people are travelling to other countries to try and get “Stem Cell” treatments for themselves or their loved ones.  This is called “Stem Cell Tourism”.   There is often no evidence that they received any real medical treatment at all.

Even in countries with strict rules on the safety, effectiveness and quality of medicines, there is sometimes no guarantee right now that a clinic offering  “Stem Cell” treatment has scientific evidence to back up its cliams.

Regenerative Medicine and Stem Cell Research are new areas In medicine. In some countries, such as the USA and Japan,  healthcare safety and quality control regulators  have not yet updated the laws to cover these very new ideas.

Some researchers claim that their techniques are not coveed by existing healthcare laws. For example, they say that taking cells from an Adult Human patient,  altering them and re-injecting them into the same person is not regulated., and does not have to go through the safety, effictiveness and quality control steps the law usually demands for a new treatment.


Watch out for news of properly run clinical trials making progress on repairing the Retina and Optic Nerve in the future.



This page last updated August 23 2015.






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