People who donate their bodies to science might never have dreamed what information lies deep within their brains.
Even when that information has to do with sleep.
Scientists used to believe that people who napped a lot were at risk for developing Alzheimer’s disease. But Lea Grinberg with the UCSF Memory and Aging Center started to wonder if “risk” was too light a term — what if, instead, napping indicated an early stage of Alzheimer’s?
About a decade ago, Grinberg — a neuropathologist and associate professor — was working with her team to map a protein called tau in donated brains. Some of their data, published last week, revealed drastic differences between healthy brains and those from Alzheimer’s patients in the parts of the brain responsible for wakefulness.
Wakefulness centers in the brain showed the buildup of tau — a protein that clogs neurons, Grinberg says, and lets debris accumulate. Gradually, these clogged neurons die. Some areas of the diseased brains had lost as much as 75% of their neurons. That may have led to the excessive napping scientists had observed before. Although the team only studied brains from 13 Alzheimer’s patients and 7 healthy individuals, Grinberg says that the degeneration caused by Alzheimer’s was so profound they were sure of its significance.
“We are kind of changing our understanding of what Alzheimer’s disease is,” she says. “It’s not only a memory problem, but it’s a problem in the brain that causes many other symptoms.”
Although these symptoms aren’t as severe as complete loss of memory or motor functions, Grinberg says they can still hold real consequences for a person’s quality of life. “Because if you don’t sleep well every day and if you… are not in the mood to do things like you were before, it’s very disappointing, right? My grandparents were like this.”
Grinberg says it’s important to know whether napping could be an early sign of Alzheimer’s, for treating symptoms and developing drugs that could slow the progression of the disease. Although there are no prescription drugs available to treat tau buildup, she says, a few are in clinical trials.
A public health professor and neuroscientist at UC Berkeley says the new information offers hope to researchers. William Jagust, who has studied Alzheimer’s for over 30 years, says the results could help select patients for clinical trials of new drugs that require early treatment. “It’s also just very important for understanding the evolution of Alzheimer’s disease with the hope that we eventually will have a drug,” he adds.
It’ll be awhile before doctors can diagnose anyone with Alzheimer’s based on how often they doze off. “There’s no practical application of this to clinical medicine as of today,” Jagust says, “but I think it’s on the cutting edge of the very, very important questions.”
What is Alzheimer’s disease? Alzeimer’s (Alzheimer) disease is a neurodegenerative disease that leads to symptoms of dementia. Progression of Alzheimer’s disease is thought to involve an accumulation of beta-amyloid plaque and neurofibrillary tangles in the brain. Find more videos at http://osms.it/more. Study better with Osmosis Prime. Retain more of what you’re learning, gain a deeper understanding of key concepts, and feel more prepared for your courses and exams. Sign up for a free trial at http://osms.it/more. Subscribe to our Youtube channel at http://osms.it/subscribe. Get early access to our upcoming video releases, practice questions, giveaways and more when you follow us on social: Facebook: http://osms.it/facebook Twitter: http://osms.it/twitter Instagram: http://osms.it/instagram Osmosis’s Vision: Empowering the world’s caregivers with the best learning experience possible.
More and more studies are showing how regular exercise benefits the brain, and in particular, the aging brain. What’s less clear is how exactly exercise counters the cognitive decline that comes with aging and diseases like Alzheimer’s.
To find out, for nearly a decade, Ozioma Okonkwo, assistant professor of medicine at the University of Wisconsin School of Medicine and Public Health and his colleagues have studied a unique group of middle-aged people at higher risk of developing Alzheimer’s. Through a series of studies, the team has been building knowledge about which biological processes seem to change with exercise.
Okonkwo’s latest findings show that improvements in aerobic fitness mitigated one of the physiological brain changes associated with Alzheimer’s: the slowing down of how neurons breakdown glucose. The research, which has not been published yet, was presented at the annual meeting of the American Psychological Association on Aug. 9.
Okonkwo works with the 1,500 people on the Wisconsin Registry for Alzheimer’s Prevention (WRAP)—all of whom are cognitively normal, but have genes that put them at higher risk of developing Alzheimer’s, or have one or two parents who have been diagnosed with the disease, or both. In the latest study, Okonkwo recruited 23 people from the WRAP population who were not physically active. Eleven were asked to participate in an exercise regimen to improve their aerobic fitness for six months, and 12 served as the control.
All had their brains scanned to track Alzheimer’s-related brain changes including differences in how neurons metabolized glucose, since in people with Alzheimer’s glucose breakdown slows. At the end of the study period, the group that exercised more showed higher levels of glucose metabolism and performed better on cognitive-function tests compared to the controls.
“We are carrying our research full circle and beginning to demonstrate some causality,” says Okonkwo about the significance of his findings.
In their previous work, he and his team identified a series of Alzheimer’s-related biological changes that seemed to be affected by exercise by comparing, retrospectively, people who were more physically active to those who were not.
In this study, they showed that intervening with an exercise regimen could actually affect these processes. Taken together, his body of research is establishing exactly how physical activity contributes to significant changes in the biological processes that drive Alzheimer’s, and may even reduce the effect of strong risk factors such as age and genes linked to higher risk of neurodegenerative disease.
For example, in their earlier work his group confirmed that as people age, the presence of Alzheimer’s-related brain changes increases—including the buildup of amyloid, slower breakdown of glucose by brain cells, shrinking of the volume of the hippocampus (central to memory), and declines in cognitive function measured in standard recall and recognition tests.
But they found that in people who reported exercising at moderate intensity at least 150 minutes a week, as public health experts recommend, brain scans showed that these changes were significantly reduced and in some cases non-existent compared to people who were not active. “The association between age and Alzheimer’s brain changes was blunted,” says Okonkwo, “Even if [Alzheimer’s] got worse, it didn’t get worse at the same speed or rate among those who are physically active as in those who are inactive.”
In another previous study, they found the benefits of exercise in controlling Alzheimer’s processes even among those with genetic predisposition for the disease. When they divided the participants by fitness levels, based on a treadmill test and their ability to efficiently take in oxygen, they found that being fit nearly negated the effect of the deleterious gene ApoE4. “It’s a remarkable finding because it’s not something that was predicted,” says Okonkwo.
In yet another previous study, Okonkwo and his team also found that people with higher aerobic fitness showed lower amounts of white matter hyperintensities, brain changes that are signs of neuron degeneration and show up as brighter spots on MRI images (hence the name). White matter hyperintensities tend to increase in the brain with age, and are more common in people with dementia or cognitive impairment.
They form as neurons degrade and the myelin that surrounds their long-reaching arms—which helps nerves communicate with each other effectively—starts to deteriorate. In people with dementia, that process happens faster than normal, leading to an increase in white matter hyperintensities. Okonwko found that people who were more aerobically fit showed lower amounts of these hyperintensities than people who were less fit.
Given the encouraging results from his latest study of 23 people that showed intervening with exercise can change some of the Alzheimer’s-related brain changes of the disease, he plans to expand his small study to confirm the positive effect that exercise and better fitness can have in slowing the signs of Alzheimer’s. Already, his work has inspired a study launched earlier this year and funded by the National Institutes of Health that includes brain scans to track how physical activity affects biological factors like amyloid and glucose in people at higher risk of developing Alzheimer’s.
The cumulative results show that “there may be certain things we are born with, and certain things that we can’t change ]when it comes to Alzheimer’s risk], but a behavior like physical exercise might help us to modify that,” says Heather Snyder, vice president of medical and scientific relations at the Alzheimer’s Association.
The landscape of experimental Alzheimer’s disease (AD) drugs is strewn with failures, so much so that it has been referred to as “an unrelenting disaster zone”. Recognizing the greatly increasing number of patients with this disease, many biopharma companies have invested a lot of resources in attacking this problem, only to be turned away in late stage studies as happened to Merck with its BACE inhibitor, verubecestat, and Lilly with its beta-amyloid antibody, solanezumab.
Now add Biogen to the list of companies that have failed in this arena. Its drug, aducanumab, partnered with Eisai, was believed to be better in removing beta-amyloid from the brain than any agent previously tested. Many have hypothesized that beta-amyloid causes the formation of damaging clumps of debris in the brain leading to AD. Unfortunately, Biogen halted a major clinical trial with aducanumab due to a futility analysis showing that the drug doesn’t work.
This is a terrible result for Alzheimer’s patients who had hoped that this was the drug that would finally succeed in treating AD. But the demise of aducanumab is also disastrous for Biogen which had expended an enormous amount of resources into this program, likely at the expense of other opportunities. It was a risky bet and one for which Wall Street has delivered a punishing blow. Biogen’s stock dropped by nearly 30% shortly after announcing the disappointing aducanumab results.
How is Biogen going to respond? As John Carroll has reported, many industry analysts believe that there aren’t many gems in the Biogen pipeline that can make up for the loss of this potential blockbuster. In predicting Biogen’s next steps, perhaps there are some learnings from another such pipeline failure – that of Pfizer’s torcetrapib.
Torcetrapib was the first of a class of compounds known as CETP inhibitors, drugs that both raised HDL-cholesterol and lowered LDL-cholesterol. A CETP inhibitor had the potential to remodel a heart patient’s lipid profile thereby greatly reducing his risk of a heart attack or stroke. There was tremendous excitement generated in this potential breakthrough treatment, not just in Pfizer but also among cardiologists and heart patients. In fact, internal commercial analyses predicted annual sales in excess of $15 billion. However, as happened with aducanumab, on December 4th, 2006, Pfizer announced that torcetrapib failed its long-term clinical study. The drug was dead. The Wall Street reaction was swift, albeit not as dramatic as Biogen’s experience. Pfizer stock dropped 10% as a result of this news.
Skills-based Hiring Goes Coast-to-Coast
Internally, the Pfizer reaction was intense. Torcetrapib was supposed to be the blockbuster that would drive growth into the next decade. Its loss created an enormous hole. Pfizer CEO Jeff Kindler responded in a couple of ways. First, he decided to “right size” R&D in relation to lower expected future revenues. In effect, hundreds of millions of dollars needed to be cut from R&D. Pfizer’s R&D budget had already undergone major portfolio adjustments and reorganizations over the previous five years due to the acquisition of Warner-Lambert Parke-Davis in 2000 followed by the acquisition of Pharmacia in 2004. Meeting the new R&D budget targets weren’t going to be achieved by simple cuts; rather, major research sites had to be closed and jobs had to be eliminated. Gone were R&D sites around the world including those in France, Japan and, most significantly, the iconic laboratory in Ann Arbor, Michigan.
But budget cuts weren’t going to be enough for Pfizer to meet its desired goals. The company began assessing major M&A opportunities and in 2009 it acquired Wyeth for $68 billion leading to yet another round of reorganizations and portfolio reshuffling. The ripple effect of the torcetrapib demise was felt by the entire company and lasted for a number of years.
So, how will Biogen respond? Undoubtedly, there will be budget cuts. In addition, perhaps Biogen will look at its R&D portfolio and give a higher priority to those programs that have the potential to deliver revenues in the short term. There might also be a push to drop programs deemed to be very risky or where the proof-of-concept requires long, expensive clinical trials. Finally, it wouldn’t be surprising to see Biogen become aggressive in their M&A activities. But make no mistake. The death of an important drug like aducanumab will have both a short and a long term effect on Biogen as a company and especially on R&D.
More than 30 million people worldwide suffer from Alzheimer’s disease – the most common form of dementia. Unfortunately, there is no cure, only drugs to ease the symptoms. However, my own research suggests a way to treat the disease. I have found the strongest evidence yet that the herpes virus is a cause of Alzheimer’s, suggesting that effective and safe antiviral drugs might be able to treat the disease. We might even be able to vaccinate our children against it……..