Scientists have found a new way to deliver drugs directly to the brain, raising hopes of more effective treatments for Alzheimer’s disease sufferers.
A team from University of Oxford successfully switched off a gene implicated in Alzheimer’s disease in the brains of mice by exploiting tiny particles naturally released by cells, called exosomes.
The exosomes, injected into the blood, act as ‘drugs vehicles’ – crossing the normally impermeable blood-brain barrier to the brain where they are needed.
This barrier is a natural defence against potentially harmful chemicals floating around the body but has also stopped useful drugs reaching the brain as well.
The scientists say the research, published in the journal Nature Biotechnology, is still at an early stage – and is many years from being tested in people.
Alzheimer’s disease
But it could also make it easier to treat Parkinson’s disease, motor neurone disease and muscular dystrophy.
Lead scientist Dr Matthew Wood said: ‘These are dramatic and exciting results.
‘It’s the first time new ‘biological’ medicines have been delivered effectively across the blood-brain-barrier to the brain.
‘This is the first time this natural system has been exploited for drug delivery.’
Over the years, many drugs have been developed to target specific parts of the disease pathways.
But while these have shown good results in the lab, getting them to the right part of the body has often proved problematic.
‘The major barrier for these drugs is delivery,’ said Dr Wood said.
‘This problem becomes even greater when you want to reach the brain. The blood-brain barrier – which stops most things in the blood stream from crossing to our brains – is much too great an obstacle.
‘We’ve shown that a natural system could be exploited to deliver drugs across the blood-brain barrier. We believe we can use this same technology for Alzheimer’s, motor neurone disease, Parkinson’s and Huntington’s.’
Safety tests would be needed before the technique could be used on people, he added.
The Alzheimer’s Society welcomed the findings but said more research was needed to see if the method would be effective.
Dr Susanne Sorensen, head of research at the charity, said: ‘In this exciting study, researchers may have overcome a major barrier to the delivery of potential new drugs for many neurological diseases including Alzheimer’s.
‘The blood-brain barrier protects the brain from harmful chemicals but also makes it difficult for drugs to reach the target cells. If this delivery method proves safe in humans, then we may see more effective drugs being made available for people with Alzheimer’s in the future.’
The study is published in Nature Biotechnology.
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Brain scans may be able to indicate potential Alzheimer’s patients years before symptoms appear, according to the results of a small study.
Research published in Neurology showed parts of some patients’ brains had shrunk up to a decade before signs of Alzheimer’s would otherwise be evident.
Alzheimer’s Research UK said there was stong evidence that the disease began to develop in mid-life.
Early diagnosis may one day prove vital in enabling effective treatment.
Sixty-five patients, all of whom started with normal brain function, took part in the study at Massachusetts General Hospital and the Rush University Medical Center in the US.
MRI scans were taken and the thickness of regions of the brain were measured.
Twenty per cent of patients with brains of average thickness went on to develop Alzheimer’s.
However, no patients with thicker brains developed the disease, while 55% of those with thinner ones also contracted it.
Dr Brad Dickerson, lead author and neuroscientist at the Massachusetts General Hospital, said: “We used what we know about the signature brain changes seen in patients with Alzheimer’s dementia, measured those areas in individuals with no symptoms and eventually determined that those who ultimately developed dementia showed subtle shrinking long before they had any symptoms.”
In the UK, one in 14 people over the age of 65 has Alzheimer’s disease.
Research suggests that it takes several years before the disease produces noticeable symptoms.
It means any form of treatment might need to start in middle age, so early diagnosis would be vital.
Rebecca Wood, chief executive of Alzheimer’s Research UK, said: “This adds to growing evidence that the changes associated with Alzheimer’s disease begin long before symptoms start to appear.
“However, this is a small study and it needs to be expanded before we can be certain of the method’s accuracy in predicting Alzheimer’s.
The authors acknowledge that further work involving many more patients is needed.
A new research suggests that magnetic resonance imaging (MRI) could help detect Alzheimer”s disease (AD) at an early stage, before irreversible damage has occurred.
With no known treatment to alter its course, AD exacts an enormous toll on society. The Alzheimer”s Association estimates that 5.4 million Americans are living with the disease today.
“One of the things that made our study novel was that we looked at patients who were cognitively normal at baseline, rather than people with mild cognitive impairment,” said lead author Gloria C. Chiang.
For the study, researchers looked at whether automated brain volume measurements on MRI could accurately predict future memory decline in elderly people with normal cognitive ability. They assessed 149 participants with an initial baseline MRI scan and a neuropsychological assessment.
Follow-up exams two years later showed that 25 of the 149 initially cognitively normal participants, or 17 percent, had memory decline.
Researchers looked at volume changes across a number of regions in the temporal and parietal lobes. The parietal lobe is primarily associated with the processing of sensory information and is involved in a number of cognitive and language processes.
The predictive accuracy of the classification model increased as the number of brain regions included in the model increased. Models that took into account several areas of both the temporal and parietal lobes had an 81 percent accuracy rate in discriminating between cognitively normal people with and without memory decline.
The findings illuminated how the interaction between these brain regions may play a key role in memory loss.
The study represents another step in the process of incorporating imaging into the diagnosis and management of Alzheimer”s disease, according to Chiang.
The study has been published online and in the June print edition of Radiology.