Ingenious use of stem cell research brings treatment for incurable condition closer
Adele Johnson was 26 when she was involved in a motorway accident in 2009. She sustained only minor injuries and was able to walk away from the crash. But several weeks later she still felt stressed, tired and depressed.
Johnson's condition initially baffled doctors, but a cardiologist provided a diagnosis: she had long QT syndrome, an incurable, potentially lethal inherited heart condition.
"It had never been spotted and it was only later, when the rest of my family was tested, that we discovered that my father and two of my three sisters also had long QT," said Johnson, who is now training to be a youth worker.
Long QT causes serious disruptions to the heartbeat and is associated with a range of symptoms. At its most serious, the condition can set off a problem called an arrhythmia, which can result in heart failure. Some families discover they are affected by long QT only when a member, sometimes a child, dies. About 30,000 people are thought to have the condition in the UK.
Treatments can mitigate the worst effects of long QT, but these can have serious side-effects. Now, however, hopes of countering long QT's worst effects have been boosted by scientists working on a pioneer project involving stem cell technology. They have re-created pulsating clumps of patients' heart cells in laboratories to use as test beds for new treatments. A heartbeat has five component waves, called P, Q, R, S and T. In long QT, the gap between the Q and T waves is abormally long, which leads to heartbeat instabilities.
"At present, treatment of long QT involves prescribing beta-blockers for the rest of a patient's life or fitting them with a small electronic defibrilator to keep their heartbeat regular," said Professor Chris Denning of Nottingham University. "However, both have serious side-effects. Beta-blockers can induce fatigue and nausea, and some patients simply cannot tolerate them. Equally, surgically fitting devices to control a patient's heartbeat is tricky, particularly if you are dealing with children."
But testing drugs on heart cells is also a tricky process. "We need a supply of patients' heart cells, so we can try different drugs on them," said Denning. "However, we cannot keep cutting patients open to remove heart tissue samples. That is just not practical or ethical."
Researchers at Denning's laboratory – backed by funds from the British Heart Foundation and Heart Research UK – have devised an ingenious solution. They take samples from patients' skin and use these to create heart cells. The skin cells are first bathed in nutrients which transforms them into stem cells, a type of cell that can be turned into any tissue. Using other techniques, the researchers are then able to turn these basic stem cells into specialist heart cells.
"The crucial point is that these heart cells can be grown in the laboratory. You put them in Petri dishes and you can see them pulse just as heart cells do in the body. And because they are taken from the skin of patients with long QT, they carry the genetic flaw that causes the condition. That means they are ideal for testing drugs on. It is an incredibly important development."
Denning added that several candidate drugs had already been identified by researchers and these were now being tested. "I am hopeful we can make real progress towards using them in clinics in the next five years."
For patients like Johnson, that cannot come soon enough. "I was a keen runner, skier and surfer, and have had to give all those up in case I trigger an arrhythmia. I even have to switch my phone off at night in case it goes off and the sudden shock triggers an arrhythmia. I am a very positive person, but that sort of thing does tend to get you down."
You can help fight heart disease and fund vital research by joining in the British Heart Foundation's Ramp up the Red event on Friday. See bhf.org.uk/red for details.This article was written by Robin McKie Science editor, for The Observer on Sunday 2nd February 2014 00.05 Europe/London
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