Snuffing Out Alzheimer’s

Hot on the heels of Friday’s blog – Sniffing Out Alzheimer’s, British scientists just announced a major breakthrough that could, one day, result in a treatment for Alzheimer’s, Parkinson’s, Huntington’s and other neurodegenerative diseases.

In tests on mice, researchers from the toxicology unit of the Medical Research Council showed brain cell death from prion disease could be prevented.

Professor Roger Morris, from King’s College London, said: “This finding, I suspect, will be judged by history as a turning point in the search for medicines to control and prevent Alzheimer’s disease.”

It is rare to get cautious scientists keen to describe any study as a turning point in history, let alone a study in mice.

Not only is it is early science, a lot can go wrong between a drug for mice and a drug for humans and the only published data is for prion disease, not even Alzheimer’s.

So why the excitement?

It is the first time that any form of neurodegeneration has been completely halted, so it is a significant landmark. It shows that the process being targeted has serious potential.

The research team focused on the natural defense mechanisms built into brain cells. When a virus hijacks a brain cell it leads to a build-up of viral proteins. Cells respond by shutting down nearly all protein production in order to halt the virus’s spread.

However, many neurodegenerative diseases involve the production of faulty or “misfolded” proteins. These activate the same defenses, but with more severe consequences. The misfolded proteins linger and the brain cells shut down protein production for so long that they eventually starve themselves to death.

This process, repeated in neurons throughout the brain, can destroy movement or memory or even kill, depending on the disease.  It  is thought to take place in many forms of neurodegeneration, so safely disrupting it could treat a wide range of diseases.

The researchers used a compound which prevented those defense mechanisms kicking in and in turn halted neurodegeneration.

The study showed mice with prion disease developed severe memory and movement problems. They died within 12 weeks. However, those given the compound showed no sign of brain tissue wasting away.

Lead researcher Professor Giovanna Mallucci says: “They were absolutely fine, it was extraordinary. What’s really exciting is a compound has completely prevented neurodegeneration and that’s a first. This isn’t the compound you would use in people, but it means we can do it and it’s a start.“

She said the compound offered a “new pathway that may well give protective drugs” and the next step was for drug companies to develop a medicine for use in humans.

Side effects are an issue. The compound also acted on the pancreas, meaning the mice developed a mild form of diabetes and lost weight. Any human drug would need to act only on the brain.

David Allsop, professor of neuroscience at Lancaster University described the results as “very dramatic and highly encouraging.”

SRxA’s Word on Health agrees.  We look forward to seeing further research and how these findings could apply to diseases such as Alzheimer’s and Parkinson’s.

Mad Cows and English Women

Having spent many years living and travelling in Europe, and having worked in both the growth hormone and blood products industry, I’ve probably had more than my fair share of potential exposure to prions.  I’ve certainly attended enough scientific meetings, written enough position papers and sat through way too many chilling and tragic BBC news broadcasts on the subject. Here in the US, however, the subject has generated relatively little media or clinical attention. So I was interested to hear that the Centers for Disease Control and Prevention (CDC) has just published the results of its investigation into the risk of human exposure to prion disease. Specifically they looked at the risks associated with:

• hunting
• venison consumption
• travel to areas in which prion diseases have been reported

in relation to three prion diseases: bovine spongiform encephalopathy (BSE or “Mad Cow Disease”), variant Creutzfeldt-Jakob disease (vCJD), and chronic wasting disease (CWD) of deer and elk.

Although rare, human prion diseases such as vCJD, result in the brain developing sponge-like holes. This causes progressive memory and personality changes, dementia, and problems with eyesight, speech and movement. CDC investigators evaluated the results of a 2006-2007 survey conducted in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, and Tennessee, as well as five counties in the San Francisco Bay area, seven counties in the Greater Denver area, and 34 counties in western and northeastern New York. Survey participants were asked about behaviors that could be associated with exposure to the agents causing BSE and CWD, including travel to the nine countries considered to be BSE-endemic:

• United Kingdom
• Republic of Ireland
• France
• Portugal
• Switzerland
• Italy
• The Netherlands
• Germany
• Spain

…and their cumulative length of stay in each of those countries. 29.5% of survey respondents reported travel to at least one of the nine BSE endemic countries since 1980. Travel to the UK was reported by 19.4%, and the median duration of travel was 14 days.

Respondents were asked if they ever had hunted for deer or elk, and if that hunting had taken place in northeastern Colorado, southeastern Wyoming or southwestern Nebraska, areas considered to be CWD-endemic. They were also asked if they had ever consumed venison, the frequency of consumption, and whether the meat came from the wild. 18.5% of survey respondents reporting having hunted for deer or elk. Of these, 1.2% reported having hunted for deer or elk in CWD-endemic areas. Venison consumption was reported by 67.4% of respondents with 88.6% of those having obtained all of their meat from the wild.

The CDC advises hunters in CWD-endemic areas to take simple precautions such as avoiding consuming meat from sickly deer or elk, avoiding consuming brain or spinal cord tissues, minimizing the handling of brain and spinal cord tissues, and wearing gloves when field-dressing carcasses.

And while the Agency did not warn against travel to Europe they say that the prevalence and extent of travel to the UK indicate that prion health concerns may also become issues for US residents. “While prion diseases are rare, they are generally fatal for anyone who becomes infected. More than anything else, the results of this study support the need for continued surveillance of prion diseases,” commented lead investigator Joseph Y. Abrams, MPH, National Center for Emerging and Zoonotic Infectious Diseases.

As always, Word on Health will be the first to let you know if there are any developments, providing of course that we stay stateside and become vegetarians!