Researchers at the Harvard Stem Cell Institute in Boston, USA, have successfully transformed one type of adult cell in to another cell type in live mice, according to a study published in the journal Nature. The cells created were insulin-producing beta cells of the pancreas - the cells that are destroyed in people suffering from diabetes - raising the prospect that the research may lead to the development of better therapies, not only for diabetes, but for a wide range of degenerative disorders such as cardiovascular or neurodegenerative diseases.
The researchers found that when the procedure was performed in mice that have had all their beta cells destroyed in order to mimic diabetes, it restored their ability to produce insulin. 'It didn't cure the [mice], but they were able to reduce their blood sugar levels to near-normal' said Professor Douglas Melton, who led the study. He added: 'now that it's shown that you can turn one of your cells into another, it makes you think of what other cells you'd like to convert'.
The goal of regenerative medicine is to create a supply of cells to replace those that are lost or have become dysfunctional through accident or disease. It has been a rapidly growing field since scientists were first able to isolate embryonic stem cells (ES cell) and grow them in a laboratory. ES cells have the unique ability to divide indefinitely and develop into any cell type in the body. Adult cells, by contrast, cannot replicate forever and have previously been believed to be committed to their specific cell type.
However, the Harvard team have shown that it is possible to reprogram an adult cell so that it converts to a different cell type. They used genetically-engineered viruses to deliver three key genes to the so-called 'exocrine' cells, which make up 95 per cent of the pancreas and produce enzymes needed for food digestion. The genes, which have the ability to turn other genes on or off thus acting as 'maser controllers, prompted the endocrine cells to change their appearance and function, to look more like beta cells and, more importantly, to produce insulin instead of digestion enzymes.
The technique was based on one used to convert adult cells into induced pluripotent stem cells (iPS cells), which have similar properties to ES cells. It is an important advancement as it achieves 'one-step cell-type conversion', rather than taking the cells back to an embryonic state and then persuading to form the required cell type. Further research will be needed to establish why the converted beta cells do not form islets (the insulin-producing structures in the pancreas) like true beta cells, and to apply the technique to human cells.