The little-known blood pressure pill benefits that could be dementia game-changer

Think of dementia and you’ll probably think about the most common form: Alzheimer’s disease. The second most common type – vascular dementia – can get overshadowed. Caused by disease of the brain’s blood vessels, it is usually said to be responsible for 20 to 30 per cent of dementia cases. However, we may also be underestimating its impact. The latest research suggests it is more common than is thought, often occurring alongside an Alzheimer’s diagnosis but going unrecognised. The good news is that there are several drugs already in use for other conditions that cut the odds of vascular dementia, including the humble blood pressure pill. And there are further treatments around the corner that could be more potent still. Shorts Scientists have thought since the 1980s that Alzheimer’s is caused by build-up of two toxic proteins in the brain. First, a protein called amyloid was implicated, then one called tau. The neat theory with the tempting solution of clearing away the proteins meant that for decades, studies of amyloid and tau soaked up most of the research funding for dementia. Today, there are about 200 clinical trials under way in Alzheimer’s disease, compared with about 50 for all other forms combined, which includes vascular dementia, says Dr Richard Oakley, associate director of research and innovation at the Alzheimer’s Society. Despite its name, the charity supports families affected by all forms of dementia. The recent development of drugs that can clear amyloid from the brain, although not yet approved for NHS use, has meant families of people with vascular dementia can feel left out, Oakley says. “People see the excitement about Alzheimer’s and say what about vascular dementia?” he adds. Vascular dementia has always seemed a more knotty problem. In about a third of those affected the cause is a stroke, a localised area of brain damage caused by a sudden blood clot or bleed. In the rest of vascular dementia cases, the brain damage is spread out and has happened over many years. It is caused by problems with the walls of small blood vessels in the brain. With ageing, blood vessels can become leaky, stiff and unable to widen when necessary to supply enough nutrients to the brain’s nerve cells and take away their waste. What this means for Alzheimer’s Over time, this damages nerve cells and eventually kills them – which leads to the dementia symptoms of memory loss and confusion. People with memory problems who get brain scans and other tests may eventually be told they have either Alzheimer’s or vascular dementia or one of the other rarer types. A small proportion may be told they have a mix of both Alzheimer’s and vascular dementia. But the distinction between vascular dementia and Alzheimer’s may be less clear than is usually thought, says Professor Adam Greenstein, a clinician scientist at the University of Manchester. Brain scans can show vascular dementia, the second most common type (Photo: Andrew Brookes/Getty) That’s because latest research shows that when blood vessels cannot clear nerve cell waste, this worsens build-up of toxic proteins such as amyloid. And in a vicious circle, when there is excess amyloid, it also builds up within blood vessel walls, further restricting blood flow. “So, this condition we call Alzheimer’s, which everybody has always talked about as being a neurodegenerative condition, is also to a large degree, a [blood vessel] illness,” says Greenstein. The drugs that can already help prevent dementia Those diagnosed with vascular dementia are usually told there are no treatments. But this ignores the fact that, if caught at the earliest stages of memory loss, known strategies for keeping blood vessels healthy can cut the number of people who progress to dementia. The most obvious step is to keep blood pressure under control, as high blood pressure further damages the brain’s small blood vessels. Blood pressure drugs were shown last year to cut dementia diagnoses. An authoritative review of dementia prevention measures drawn up by the Lancet Commission identified 14 risk factors that people could avoid, and many involved blood vessel health. They include standard lifestyle measures like stopping smoking, cutting alcohol, keeping fit and controlling cholesterol. “We’ve long known that what’s good for your heart is good for your head,” says Oakley. As our understanding of vascular dementia has grown it has opened the way for more specific treatments that can target the underlying blood vessel disease, says Professor Joanna Wardlaw, head of neuroimaging at the University of Edinburgh. The promising new, cheap drugs Two drugs already used to open up blood vessels to treat chest or leg pain, are currently being tested in three UK trials for vascular dementia, having shown promising results in a smaller study. If they work, they are likely to be available in the next few years because they are relatively cheap – unlike the two amyloid-clearing treatments that have been banned for NHS use partly because of their cost. “It may be that in 10 years’ time, people receive several different drugs,” says Wardlaw. “Something to help the blood vessels, something to get rid of the proteins and maybe something to damp down inflammation.” In the meantime, though, at least some dementia specialists are starting to tell patients with mild memory problems that simple measures such as blood pressure control can cut their risk of progressing to full dementia. Greenstein’s hospital has just opened the Manchester Brain Health Centre, a clinic designed to give earlier dementia diagnosis. They advise people at the stage of mild memory loss how to keep their brain’s blood vessels as healthy as possible. “Nobody would tell you if you presented with chest pain to go away and come back after you’ve had your first heart attack,” says Greenstein. “We know that in vascular conditions, you have to pick things up early and treat them aggressively. This is what we are trying to do.”