Stem cells are cells produced in the body that have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialised function, such as a muscle cell, a red blood cell, or a brain cell.
There are three types of stem cells:
Induced pluripotent stem cells (iPS cells)
Recently, a third type of stem cell, with properties similar to embryonic stem cells, has emerged. Scientists have engineered these induced pluripotent stem cells (iPS cells) by manipulating the expression of certain genes – ‘reprogramming’ cells back to a pluripotent state. The Nobel Prize in Medicine was awarded in December 2012 to Shinya Yamanaka for this discovery.
Tissue stem cells
Tissue stem cells – also sometimes called adult stem cells – are derived from foetal or adult tissue. Usually they can only give rise to the cells of that tissue. In some tissues, these cells sustain turnover and repair throughout life. For example, stem cells that are found in the skin will produce new skin cells, ensuring that old or damaged skin cells are replenished.
Embryonic stem cells
These cells derived from a small group of cells (called the inner cell mass) within the very early embryo. Human embryonic stem cells are obtained from embryos that are 5-6 days old. At the stage that embryonic stem cells are derived, the embryo is called a blastocyst, and is no bigger than a grain of sand. Embryonic stem cells are able to form all the different types of cell in the body.
Cell Therapy Research for Retinal Degenerations
Stem cell technology holds great potential for improving the sight of people with a visual impairment, particularly to replace photoreceptors that have been lost due to degeneration. A number of studies are currently being undertaken in order to develop new therapies to treat, and/or prevent a loss of vision. Central to this research is the development of our understanding of how different types of stem cells behave, and how best to harness their potential in the eye. It is important to realise that stem cells are not a one-stop, generic cure, but they do hold exciting potential for vision repair.
Grants Supported by Fighting Blindness
2011: Cell therapies for treatment of diverse retinal disorders – Prof Jane Farrar, Trinity College, Dublin. For more information, read point 1 below.
2008: Potential of umbilical cord derived cells for retinal stabilisation and repair – Dr Reaz Vawda, Dublin City University.
2007: Exploration of cell based therapies for retinal degradations – Prof Jane Farrar, Trinity College, Dublin.
2006: Development of cell-based therapies for the treatment of photoreceptor degeneration in murine models of retinitis pigmentosa – Dr Marius Ader, Trinity College Dublin.
2006: Directing retinal stem cells to become functionally integrated cone photoreceptors in host retinas – Dr Breandán Kennedy, UCD.
1. Adult Stem Cell Technology: Stem cell therapies for the treatment of diverse retinal disorders
Prof Jane Farrar and Dr Fiona Mansergh, Trinity College Dublin
This is a continuation of our investment into adult stem cell research, first funded in Trinity College Dublin by Fighting Blindness in 2003. For almost ten years we have been pursuing the use of stem cells with great hope for the potential they have in developing therapies and cures for inherited blindness.
A stem cell is in essence a “blank” cell which is capable of becoming a specific. They hold enormous potential for degenerative conditions that result in the loss or death of cells, such as the loss of photoreceptor cells in retinitis pigmentosa.
Prof Jane Farrar is working alongside Dr Fiona Mansergh at TCD to look at models of retinal degenerations and will be investigating retinal stem cells specifically. They will work with the cells and transplant them into animal models with retinal degenerations that are similar to those experienced by humans. This will establish if there is any therapeutic benefit associated with transplantation of these stem cells.
The exploration of cell therapy and regenerative medicine for the treatment of retinal degenerations is a priority for Fighting Blindness as we want to ensure that we are enabling treatments and cures in the fastest possible time frame.
Global Stem Cell Research
Stem cell clinical trials are currently very much in their infancy for retinal degenerations; however there are a number of clinical trials underway for Stargardt disease and age-related macular degeneration in particular. Preclinical data in mice from one group in the United States have shown that transplantation of human neural stem cells protect the retina from progressive degeneration and preserve visual function. This research was performed by the company StemCells and they hope to build upon this promising work with a clinical trial that they opened in June 2012.
Research News: July 2013
A group of scientists in the UK led by Prof Robin Ali, Chief Scientific Advisor with Fighting Blindness, carried out the first successful transplant of light-sensitive photoreceptor cells taken from a synthetic retina, grown ‘in a dish’ from stem cells. Read the full story here.
(Please note: Fighting Blindness cannot be held responsible for information from other websites)
Explore Stem Cells: Expert advice on stem cells (for beginners)