DENTAL pulp taken from the centre of extracted teeth is being tested as a way to treat depression in a new trial.
The theory is that stem cells - master cells that can grow into different kinds of specialised cells - in the pulp may help to encourage the formation of new nerve cells in the brain.
The researchers behind the trial believe that the more nerve cells there are, the better the communication between these cells and between brain areas responsible for our emotions.
Stem cells are also anti-inflammatory and it is thought that depression may be linked to inflammation in the brain.
The trial follows the breakthrough finding that antidepressants may trigger stem cells in the brain into making more nerve cells.
Around one in 10 people suffers from depression at some time during their lives, according to NHS figures. The exact cause is not fully understood.
Levels in the brain of mood chemicals such as serotonin are thought to be involved - most antidepressants are designed to work by increasing serotonin levels - but this chemical imbalance theory is unproven.
There are many other factors too, including genetic susceptibility and stressful life events.
However, researchers now believe that nerve cell growth, and the connections between nerve cells, play an important part.
Previous studies have found that the hippocampus area of the brain, which is involved in memory and emotion in response to those memories, is smaller in patients with chronic depression.
This, suggest some experts, may explain why antidepressants take time to work. They boost brain chemicals such as serotonin and dopamine, but it can be a few weeks before they take effect. It may be that mood only improves when new nerve cells grow and form new connections, a process that takes weeks.
Ongoing research at Johns Hopkins University in the US has shown that antidepressants can trigger the growth of stem cells in the brain. They found exercise has a similar effect. In the new trial, 48 people diagnosed with depression will be given stem cells taken from the pulp of other people's extracted teeth, plus the antidepressant fluoxetine.
The cells will be processed and cleaned before being injected into patients' arms in four sessions, each two weeks apart. A comparison group will have only fluoxetine daily.
Commenting on the approach, Carmine Pariante, a professor of biological psychiatry at King's College London, says: "In the short-term, stress increases the production of chemicals in the body that are helpful in the fight-or-flight response.
"For example, stress increases inflammation, which protects us from infection.
"However, psychosocial stressors that trigger depression - such as unemployment, marital difficulties or bereavement - are typically long-lasting, and in the long-term the increased inflammation reduces the birth of new brain cells and the connection between brain cells, leading to depression."
Stem cells are also "anti-inflammatory", he says, "so in addition to creating new brain cells, they can reduce the inflammatory effects of stress on the brain."
"We know that stem cells reach areas where there is inflammation. This is how they will find their way from the blood to the brain."
© Daily Mail
