Stem cell therapy factsheet

What are stem cells?

The human body is made up of billions of cells, each one of which is derived from a single fertilised 'egg cell'. However, the body's cells are not all identical. There are at least two hundred distinct cell types, all with different features and functions, such as neurons (nerve cells), liver cells, skin cells, and so on. These specialised cells are the body's mature or fully differentiated, cells, all of which are derived from their common ancestors, stem cells.

Stem cells themselves fall into three categories of potency, or ability to differentiate into other cell types, depending on their stage of development. 'Totipotent' cells are considered the 'master' cells of the body because they contain the genetic information needed to create all of the cell types in the body. Human cells only retain this capacity during the first few divisions of a fertilized egg.

Next come 'pluripotent' cells, which are also highly versatile and can give rise to any cell type except the cells of the placenta. Embryonic stem cells are pluripotent stem cells.

Finally, in the foetus, and in some adult tissues (such as bone marrow), the stem cells found are 'multipotent', meaning that they can give rise to several other cell types, but those types are limited in number and normally specific to the organ system in which they reside. These are also termed somatic, or lineage-restricted, stem cells.

ReNeuron's stem cells fall into this final category, which we believe are the most likely to provide effective cell therapy treatments.

(click to view full size image)

The development of cell therapy

The ageing process, the onset of disease and the stresses of modern life all contribute to cell death within major organs of the body, including the brain. Cell degeneration or malfunction is the cause of serious diseases such as Parkinson's disease, Alzheimer's disease, diabetes, blindness and heart disease. Cell therapy involves replacing these dead or non-functioning cells with healthy, functioning cells of the equivalent or complementary type.

Cell therapy in one form is a proven curative medicine. It has actually been in existence for almost fifty years. The most common example is bone marrow cell therapy in leukaemia patients. Less well-known treatments include the transplantation of islet (insulin-producing) cells for diabetes, and bone and cartilage cell grafts for severe broken bones or for the rebuilding of joints.

These cell therapy treatments rely for the most part on the transplantation of healthy, mature cells, taken from the patient's own body, from donor relatives or from donated organs. However, mature, or 'differentiated', cells usually lose the ability to regenerate themselves.

For this reason, mature cells from the brain or other specialised organs cannot be grown successfully in the laboratory beyond a small number of cell divisions or 'doublings'. Consequently, cell therapy treatments using mature cells have not been successfully developed for large-scale clinical applications.

Stem cell therapy – the next generation of cell therapy treatments

Stem cells offer the potential to overcome the technical difficulties associated with existing cell therapy treatments. They can now be made to grow in the laboratory and retain the ability to differentiate into the particular specialised cell type required. For the first time, a range of groundbreaking new stem cell therapies have the potential to treat hitherto incurable diseases.

The potential of stem cells has become one of the talked about topics in the biomedical sciences. Simply put, stem cells are the primitive cells that give rise to other types of cells. To harness the power of stem cells is to harness their reparative and regenerative potential.

In certain diseases, such as Parkinson's disease and diabetes, a particular cell type in a specific location is lost. The appropriate curative treatment in these cases would be the replacement of those lost cells by the transplantation of fully mature cells of the type in deficit. In the laboratory, stem cells can be manipulated into becoming the mature cell types necessary to make such transplantation procedures effective.

The promise of stem cell transplantation therapy

Stem cell therapy offers its greatest potential in areas of significant unmet medical need.

Diseases of the brain such as stroke and Parkinson's disease can dramatically reduce the quality of life in sufferers. They consequently represent major healthcare costs, particularly in terms of long-term social care. There are no treatments that address the causes of these diseases.

Type I diabetes represents 10 per cent of the diabetes patient population. The disease affects young people and leads to the progressive destruction of the pancreas, with complications such as blindness, neuropathies, kidney and liver problems. Treatment consists of insulin replacement therapy and diet management. There is no effective cure.

Degenerative diseases of the retina, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP) represent one of the most common causes of blindness. Again, there is no effective treatment.

Stem cell transplantation therapy offers the real potential of dramatic cures for these diseases and many others. ReNeuron is positioned to play a leading role in developing treatments to realise this potential.

Top of page