Dementia: the greatest challenge of our time for health

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Family — Legend

Aging is the main risk factor for developing dementia.

Dementia is the biggest health challenge of our time, warned the charity Alzheimer's Research UK.

Dementia was first described by the German physician Alois Alzheimer in 1906 after an autopsy performed on a woman suffering from profound memory loss.

What he discovered was a greatly reduced brain and abnormalities in and around the nerve cells.

At the time, dementia was rare and was barely studied for decades.

But today, this virus is diagnosed every three seconds. It's the most deadly in some richer countries and it's completely incurable.

So what is this disease? Why does it become more common? And is there hope?

Is dementia the same as Alzheimer's disease?

Dementia is a symptom present in many brain diseases.

Memory loss is the most common feature of dementia, especially the difficulty in remembering recent events.

Other symptoms may include changes in behavior, mood and personality, loss of knowledge in familiar places or the inability to find the right word in a conversation.

This can happen to the point where people do not know that they need to eat or drink.

Alzheimer's disease is by far the most common of the diseases that cause dementia.

Vascular dementia, Lewy body dementia, frontotemporal dementia, Parkinson's disease dementia, amyotrophic lateral sclerosis and the recent discovery of Late.

New type of dementia discovered

Is this really the biggest health problem of our time?

About 50 million people in the world are currently living with dementia.

But cases are expected to reach 130 million by 2050 with the aging of the population.

According to the World Health Organization, dementia deaths have doubled since 2000 and dementia is now the fifth leading cause of death in the world.

But dementia has already taken first place in some richer countries.

In England and Wales, one in eight death certificates mentions dementia.

There is also a major difference from other leading causes of death, such as cancer or heart disease, as there is no treatment to cure or slow the rate of dementia.

"Dementia is certainly the biggest health challenge of our time," Hilary Evans, Executive Director of Alzheimer's Research UK, told BBC.

"It's the one that will continue to increase in terms of prevalence, unless we can do something to stop or cure this disease."

As the disease progresses, people eventually need full-time care and the annual cost of caring for people with dementia is around $ 1 trillion a year.

Why does it become more common?

The answer is simple: we live longer and the main risk factor for dementia is age.

This is why we expect very large increases in the number of cases of dementia in Asia and Africa.

With a more philosophical hat, you can see that dementia is the price we pay to progress in the treatment of fatal infections, heart attacks and cancer.

Although an unexpected and hopeful trend is emerging that has surprised some on the ground, the proportion of elderly people with dementia is declining in some countries.

Studies have shown that the rate of dementia (the number of cases per 1,000 population) decreased in the United Kingdom, Spain and the United States and stabilized in other countries.

This is largely attributed to improvements in areas such as heart health and education, which in turn benefit the brain.

If I live long enough, will I contract dementia?

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Dementia is not part of the normal aging process

Not necessarily.

The public felt that dementia was normally part of the aging process.

However, the research is clear: dementia is caused by an illness.

And some people who have reached the age of 90 and over have a brain that remains remarkably clear of any sign of dementia.

Professor Tara Spiers-Jones, deputy director of the Center for Brain Science Research at the University of Edinburgh, said: "I think some people would be fine, even if they were still living a hundred years. "

Why are drug trials still failing?

Have no doubt: even a drug that would slow the progression of dementia would make someone a fortune.

It's not for lack of trying that there is no cure for dementia.

The aducanumab, a drug that, one hoped for a lot in Alzheimer's disease, would be the last to date to be abandoned.

In March of this year, Biogen and Eisai announced that their drug was unlikely to be effective and ended the trial sooner.

The aducanumab, like those that have failed before, had been designed to target a toxic protein called beta amyloid that accumulates in the brains of patients with Alzheimer's disease.

If you go back to Dr. Alzheimer in 1906, some of the abnormalities discovered at this autopsy of the brain were beta-amyloid plaques.

Legend

In 1906, Dr. Alois Alzheimer discovered an "unusual illness" that resulted in memory loss, disorientation, hallucinations, and the death of a woman in her fifties.

Thus, a clear link between beta-amyloid and Alzheimer's disease appeared and the hypothesis was that the protein was killing the brain cells.

Therefore, the deletion of beta-amyloid should save brain cells and curb Alzheimer's disease, experts said.

The pharmaceutical companies have flocked.

Ms. Evans said, "Some pharmaceutical companies jumped on this idea thinking it would be the quick fix, it is not."

And they left other tracks relatively unexplored.

"Many pharmaceutical companies are putting all their eggs in one basket," says Evans.

The Power of Music: Vicky McClure's Dementia Chorus

So, is everything we know about Alzheimer's disease wrong?

Has science made a massive and expensive mistake? "Is the amyloid hypothesis" dead? These are questions asked.

Professor Bart De Strooper, Director of the UK Dementia Research Institute, said: "The amyloid hypothesis such as it has been formulated over the last 20 years is dead, I would accept .

"What I will not accept, is that the importance of amyloid is dead."

There is a ton of evidence that amyloid plays a role in some dementia.

This includes genetic studies of people with familial dementia, who develop the disease in their thirties or forties. It is caused by rare mutations in their DNA that alter the functioning of amyloid in the body.

Professor De Strooper said: "The genetic evidence for amyloid is so strong that it is difficult to go on the other side, which means that amyloid does not. Has nothing to do with the disease.

"What we need is a new theory."

So what does amyloid do?

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Beta-amyloid plaques, orange, agglomerated around neurons.

The role of beta-amyloid is being reinvented.

Thus, instead of being the toxic protein that stifles nerve cells, it is considered the initial step leading to dementia.

Prof Spiers-Jones said: "Some people call this a trigger and once you have pressed the trigger, the ball is about to arrive.

"So doing anything to trigger is no longer an effective method."

The optimistic view is that anti-amyloid drugs can play a role in the prevention of Alzheimer's disease, but only if they are used before the onset of the disease.

It may be for this reason that clinical trials on current Alzheimer's drugs have failed because patients are treated too late.

A new theory for Alzheimer's disease?

Some researchers are hoping for another protein called tau.

If beta-amyloid is the trigger, tau can be the ball.

"Tau is one of my favorite proteins, where there is tau, there is cell death in the brain," says Professor Spires-Jones.

"I think tau is very important for causing disease and cell death."

Legend

A team from the MRC Molecular Biology Laboratory in Cambridge says it has opened a "new era" in neurodegenerative disease after developing the precise structure of tau.

However, again, this is not 100% certain and there is no evidence, in human trials, that reducing brain levels of tau can prevent the death of neurons.

The focus on Alzheimer's disease could help target drugs

By focusing on neurons and dangerous proteins, we can miss the whole brain.

This lesson is based on cancer, where understanding the role played by the immune system has led to a whole new branch of medicine – cancer immunotherapy.

The immune system is also heavily involved in dementia.

If you look at genetic mutations that increase the risk of developing dementia, a good deal of them are involved in the immune system.

Although your brain is full of "thinking" neurons, they are expertly assisted by special immune cells called microglia.

They fight infections, but also keep the brain functioning by eating everything that should not be there.

And the blood vessels in the brain are increasingly seen as a key player, not only in vascular dementia, but also in other dementias.

Professor De Strooper still considers that abnormal proteins are the trigger, but "then you have the brain's response to that threat."

He told the BBC: "Some people have very good genes, a very strong inflammatory response or a very good vascular response (blood vessel), and they will stay healthy even if these biochemical changes are present in the brain."

And, on the other hand, some people genetically programmed to respond poorly would develop symptoms of dementia.

Professor De Strooper stated, "Suddenly, you open up a wide range of possible therapeutic targets, because then you can begin to think about how we can improve the brain's response on the inflammatory side, the vascular side, the neural side?

"That's what's happening right now."

Looks like we do not know exactly what's wrong in the brain?

"Unfortunately, we do not quite understand," says Professor Spires-Jones.

She said that there were key gaps in our knowledge:

We do not know why neurons die, we do not know the real cause of their death
We do not know what forms of proteins that accumulate in the brain are toxic
We do not really know why they accumulate in the first place, why they start where they do it, why they are spreading in the brain and how effective it is to stop this process at home. ;man.

"There are still big questions to understand in order to treat the disease effectively," she said.

But we stopped talking about all dementia to the benefit primarily of Alzheimer's disease, on which most of the medical research has been concentrated.

Each type of dementia has different traits, with different parts of the brain affected and different aberrant proteins that accumulate in the brain.

For example, alpha-synuclein accumulates in Lewy body dementia and Parkinson's disease dementia.

It may be necessary to set up different treatments targeting different proteins. Some patients have "mixed dementia", which creates confusion. Several diseases manifest themselves simultaneously.

Why is there such a gap in our knowledge?

There are two important factors: one is the very complexity of the brain and the other the lack of funding for research.

The human brain is the most complex structure of the known universe and is composed of 100 billion neurons.

Steal the analogy of Strooper's Prof; if every person on the planet (currently about 7.5 billion) had a computer and they were all connected and working together, that would still be less than one-tenth of what's going on in the brain.

And yet, for every scientific study published on any form of neurodegeneration, there are 12 studies on cancer.

The focus was simply put elsewhere.

What should be the quality of a treatment?

Less than you might think.

The goal is to completely cure all forms of dementia, but drugs that slow down the pace of dementia could present tremendous benefits.

According to an analysis by Alzheimer's Research UK, a drug that would delay the onset of dementia by five years would reduce the number of people with the disease by one-third.

The reason is that dementia tends to be a disease of old age, and if you can buy a little time, you may well have died of other causes before your brain is hit.

Slowing down the decline would also allow people to live independently longer.

Can my brain resist dementia?

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Huge loss of brain tissue in a patient with dementia (left) versus a healthy brain (right).

Professor Spires-Jones said, "How resilient is the brain? It's phenomenal!"

When a stroke kills brain cells, it is possible to regain some degree of loss of function. But this does not come from the growth of new brain cells, but from the reconnection of those that remain.

Professor Spires-Jones told the BBC: "In Alzheimer's disease and other dementias, the brain is able to cope in a similar way by altering the network."

In fact, enormous damage has already been caused to the brain by the time a family doctor diagnoses Alzheimer's disease.

"When you look at people at this point, they have already lost half of the neurons of a part of the brain that is really important to the memory, the cortex entorhinal," said Professor Spiers-Jones.

But this creates a new problem: starting treatment at this stage will not recover these lost brain cells. You are primarily born with all the brain cells you will ever have (with few exceptions).

How do the treatments work then?

Let's move quickly to a world where we have treatments and where the main asset of the brain, its capacity for adaptability, is the problem because it has been able to mask the disease for more than 10 years.

Ms. Evans, of Alzheimer's Research UK, said: "There is no point in stopping the progression of the terminal illness."

However, it will not be practical either that everyone undergoes a regular brain examination to detect dementia early, because these exams are extremely expensive.

One of the options is the approach taken in heart disease, where millions of people take pills to lower cholesterol levels to prevent clogging of their arteries.

Statins reduce the risk before people have a medical problem.

Ms. Evans said, "I think the analogy with statins is good.

"I think there might be something you could take in the middle of your life that could then reduce your risk or make sure that the development of this disease is slow."

Prof. Strooper is considering a screening system for people who could even start at birth with a DNA test to predict who is at greatest risk.

Regular cognitive tests carried out throughout life would then constitute a rapid alert system for those requiring a more detailed examination.

And patients who turn out to already have a diseased brain would be offered drugs that would prevent the death of brain cells, even before the symptoms appear.

Is there anything I can do to dodge dementia?

Legend of the mediaDo you want to avoid dementia? This could help

There is no guarantee, but there are ways to reduce the risk of developing dementia.

Research finds that a lifestyle change, including:

We do not really understand why they protect the brain.

Do these lifestyle factors really stop the process of dementia in the brain?

Or do they prepare the brain for dementia by increasing the connections and flexibility of the brain so that when the neurons begin to die, the brain can compensate for longer and the symptoms do not appear?

On a personal level, it probably does not matter – do not catch dementia, it's not catching dementia. Scientifically, the questions are important because the answers will shed light on what is happening in the brain.

"People who are very healthy and take good care of themselves are the group that, in my opinion, is the most resistant to Alzheimer's disease," says Professor Spiers-Jones.

So is there hope?

There is now a lot more money spent on dementia research.

The optimistic view is that we are at the same point as during the AIDS crisis in the 1980s, when HIV infection was a death sentence.

But now, people taking anti-viral drugs have an almost normal life expectancy.

Professor Spires-Jones said, "With cancer, we know that if you do a lot of research and scientific research in one area, you can make a difference and find treatments and treatments for these complex diseases.

"So, I think we're going to get there, but we need to better understand the fundamental changes in the brain to be able to offer effective treatments."

Ms. Evans said, "There are potential tests in this year that are coming to fruition, and I hope to see positive stories unfold over the next two years.

And Strooper's teacher is waiting for the first treatment in a decade: "It will not cure all dementia, I think we will have to face this for a long time.

"But this will certainly delay the disease, you will wither much more slowly and the dementia will be much less a threat to society."

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