Scientists can now track how diseases develop in a Petri dish by using stem cells and the technique could be used to provide personalised treatments
A NEW "disease in a dish" technique could help scientists develop treatments for a host of genetic disorders. Scientists have created stem cell lines that will allow them to study 10 different genetic diseases in the laboratory.
They will be able to watch the disorders develop in a range of cell and tissue types as they grow in the Petri dish. The breakthrough could open up a whole new approach to investigating diseases and their treatments. In future, it may allow scientists to be less reliant on living "models" provided by mice and other animals.
Stem cells are immature cells with the potential to grow into different kinds of tissue. Those used in the new research are "pluripotent", meaning they can be coaxed into becoming almost any cell type in the body.
A total of 20 disease-specific cell lines were created, containing the genetic errors responsible for the 10 disorders.
The diseases include two kinds of muscular dystrophy, type-1 diabetes, Parkinson's, Huntington's, Down's syndrome, and the condition that causes "boy-in-the-bubble" immunodeficiency.
A recently discovered technique was used to convert skin and bone marrow cells from patients with the diseases into the stem cells. The patients ranged in age from one month to 57 years.
By inserting certain genes into the cells, the US scientists turned back the clock and caused them to revert to an embryonic stem cell state. Technically they are known as induced pluripotent stem (iPS) cells.Previously, stem cells with the same properties could only be extracted from early-stage cloned human embryos, creating ethical problems.
The stem cells can be grown in the laboratory into all the tissues or cells affected by the disorders. For instance, brain neurons are involved in Parkinson's, and pancreatic cells in type-1 diabetes.
Chief scientist Dr George Daley, from the Children's Hospital, Boston, says: "Researchers have long wanted to find a way to move a patient's disease into the test tube, to develop cells that could be cultured into the many tissues relevant to diseases of the blood, the brain and the heart, for example.
"Now, we have a way to do just that - to derive pluripotent cells from patients with disease, which means the cells can make any tissue and can grow forever. This enables us to model thousands of conditions using classical cell culture techniques."
The research is reported online in the journal Cell.It is not the first time scientists have grown human cells to mimic diseases.
But ordinary "sick" cells taken directly from patients have a limited lifespan in the laboratory. Researchers often modify the cells to make them "immortal", but this alters their structure and makes them less reliable as models.
For this reason, much human disease research is done on genetically-engineered mice.
However, this also has shortcomings because of the vast physiological differences between mice and humans. In some cases, a genetic defect that produces a disorder in humans, such as Down's syndrome, does not cause the same symptoms in mice.
The new stem cell cultures will in many cases mimic human diseases more reliably than animal models, according to Dr Daley.
The cells are to be housed in a new facility being built at Massachusetts General Hospital in Boston, and will provide a resource for scientists around the world.
"We wanted to produce a large number of disease models for ourselves, our collaborators, and the stem cell research community to accelerate research," says Daley.
"These new lines are valuable tools for attacking the root causes of disease. Our work is just the beginning for studying thousands of diseases in a Petridish."
Disease-specific stem cells would initially be used to reproduce human diseases to understand their development in different tissues, he adds.
By generating stem cell cultures from many individuals, it may also be possible to compare how the same disease affects different people.
Ultimately, the technique could be used to provide personalised treatments, Daley predicts. A patient's own cells could be re-engineered to correct a disease-causing defect, and then re-introduced into the body.
- AP