Alzheimer's linked to unsaturated fatty acids in the brain

While it is not yet clear what causes Alzheimer's disease, researchers are examining a variety of genetic, environmental, and lifestyle causes. New research examines some of the key brain regions involved in the development of Alzheimer's and finds several fatty acids to be associated with this form of dementia.

New research examines the levels of fatty acids in brain regions vulnerable to Alzheimer's disease.

The Alzheimer's Association estimate that every 66 seconds, an adult in the United States develops Alzheimer's disease (AD). Alzheimer's-related mortality has increased by as much as 89 percent since the year 2000.

Researchers are hard at work trying to understand what causes AD. It is estimated that the disease affects 1 in 3 older adults in the U.S., and understanding why Alzheimer's tends to strike seniors, in particular, is at the heart of the medical community's research efforts.

Researchers are studying late-onset Alzheimer's in the context of age-related brain changes. A new study - published in the journal PLOS Medicine - looks at how fatty acid metabolites in the brain tissue of healthy seniors behave and affect the participants' cognitive abilities.

The international research team - led by Cristina Legido-Quigley of King's College London in the United Kingdom, and Madhav Thambisetty of the National Institute on Aging in the U.S. - conducted a nontargeted metabolite profiling study that analyzed the concentration of 100 different fatty acid metabolites in the brain tissues of seniors who participated in the Baltimore Longitudinal Study of Aging.

The participants were assessed cognitively in the year prior to their deaths, and their brain tissue was tested for neuropathologies during autopsy.

Legido-Quigley and her colleagues divided the participants into three groups: 14 participants had healthy brains, 15 had a neuropathological buildup of the tau protein or a buildup of amyloid plaque, but no memory problems, and a final group of 14 participants had AD.

Amyloid plaques and tau tangles are abnormal clusters of protein and bundles of fiber, respectively, which are considered to be the main features of AD.

Six unsaturated fatty acids linked to AD

The researchers measured the metabolite levels of the brain regions commonly associated with Alzheimer's: the middle frontal gyrus and the inferior temporal gyrus. They also examined metabolite levels in a brain area that is not normally affected by Alzheimer's pathology - the cerebellum.

The study revealed that six unsaturated fatty acids (UFAs) found in the middle frontal and inferior temporal gyri correlated with AD.

Fatty acids are essential nutrients that provide the human body with energy. Fats are made of fatty acids, which can be saturated or unsaturated. Dietary saturated fats can raise the levels of the "bad" type of cholesterol - namely, the low-density lipoprotein cholesterol - while unsaturated ones can lower it.

The fatty acids shown to correlate with AD in this study were: docosahexaenoic acid, linoleic acid, arachidonic acid, linolenic acid, eicosapentaenoic acid, and oleic acid.

Cristina Legido-Quigley and colleagues explain the significance of the study:

"[This] work suggests that dysregulation of UFA's metabolism plays a role in driving AD pathology and that these results provide further evidence for the metabolic basis of AD pathogenesis."

The authors also concede some of the study's limitations. Due to its observational nature, the research cannot explain causality, so it could not be established whether the UFA dysregulation causes AD or whether it is the other way around.

Additionally, the authors note that larger studies are needed to replicate and confirm the findings. Their study sample was small, as there are not many studies available that examined tissue samples together with cognitive evaluations. Furthermore, the nature of nontargeted metabolomic studies is quite limited, as not all metabolites can be identified at once, so further studies are needed to locate other metabolites.

Learn how scientists stopped and reversed Alzheimer's-related brain damage in mice.

Written by Ana Sandoiu

Drinking tea could help stave off cognitive decline

Thanks to its high levels of antioxidants, tea has been linked to a lower risk of diabetes, heart disease, and cancer. However, its potential health benefits may not end there. Researchers have found that regular tea consumption could more than halve the risk of cognitive decline for older adults, particularly for those with a genetic risk of Alzheimer's disease.

New research suggests that regular tea intake could lower the risk of cognitive decline in later life.

Tea is one of the most popular beverages in the United States; in 2015, more than 3.6 billion gallons of tea were consumed in the country, with black tea being the favorite.

The possible health benefits of tea consumption have been well documented. A recent study published in The American Journal of Public Health, for example, associated moderate tea intake with a reduced risk of cardiovascular events.

Past research has suggested that drinking tea may also have brain benefits, with one study linking green tea consumption to better working memory.

For this latest study, lead investigator Feng Lei, from the Department of Psychological Medicine at National University of Singapore's (NUS) Yong Loo Lin School of Medicine, and colleagues sought to determine whether there might be a link between tea intake and cognitive decline.

The researchers came to their findings - published in The Journal of Nutrition, Health & Aging - by collecting data from 957 Chinese adults aged 55 and older.

Between 2003 and 2005, the team collected information on the participants' tea consumption, including how much tea they drink, frequency of tea consumption, and what types of tea they consume.

Every 2 years until 2010, the participants underwent standardized assessments that evaluated their cognitive function.

The researchers identified 72 new cases of neurocognitive disorders among participants between 2006 and 2010.

Up to 86 percent lower risk of cognitive decline for tea drinkers

Compared with adults who rarely drank tea, those who consumed tea regularly were found to have a 50 percent lower risk of cognitive decline.

Furthermore, among adults who possessed the APOE e4 gene - which is associated with an increased risk of Alzheimer's disease - those who drank tea regularly were found to be at 86 percent lower risk of cognitive decline.

These findings remained after accounting for numerous confounding factors, including the presence of other medical conditions, social activity, physical activity, and other lifestyle factors.

The researchers note that the cognitive benefits were seen with consumption of tea that was brewed from tea leaves, such as green tea, black tea, and oolong tea.

The study was not designed to pinpoint the mechanisms behind tea's potential brain benefits, but Lei says that it could be down to the beneficial compounds the beverage contains, such as theaflavins, catechins, thearubigins, and L-theanine.

"These compounds exhibit anti-inflammatory and antioxidant potential and other bioactive properties that may protect the brain from vascular damage and neurodegeneration," Lei explains. "Our understanding of the detailed biological mechanisms is still very limited so we do need more research to find out definitive answers."

A 'simple, inexpensive lifestyle measure' could prevent dementia

According to the World Health Organization (WHO), around 47.5 million people worldwide are living with dementia, and there are around 7.7 million new cases of the condition every year.

By 2050, it is estimated that the number of people living with dementia will have risen to 135.5 million.

Although the study from Lei and team was conducted in Chinese adults, the researchers say that their findings are likely to apply to other populations, and they could have important implications for the prevention of dementia.

"Despite high-quality drug trials, effective pharmacological therapy for neurocognitive disorders such as dementia remains elusive and current prevention strategies are far from satisfactory.

Tea is one of the most widely consumed beverages in the world. The data from our study suggests that a simple and inexpensive lifestyle measure such as daily tea drinking can reduce a person's risk of developing neurocognitive disorders in late life."

Feng Lei

The researchers plan to conduct further studies on the link between tea and cognitive function. In particular, they want to carry out randomized controlled trials to rigorously test the health effects of tea's bioactive compounds.

Learn how a compound in green tea could help to treat Down syndrome.

Written by Honor Whiteman

Psychiatric disorders do not increase risk of Alzheimer 's disease

Psychiatric disorders do not increase the risk of Alzheimer's disease, according to a recent study from the University of Eastern Finland. However, the prevalence of psychiatric diagnoses increased before the Alzheimer's diagnosis, which might be due to prodromal symptoms of Alzheimer's disease. The results were published in European Psychiatry.

History of mood disorder, such as depression, or any psychiatric disorder were associated with a higher risk of Alzheimer's disease when psychiatric disorders that occurred at least five years before the Alzheimer's diagnosis were taken into account. However, the associations disappeared when this time window was extended to 10 years. The exponential increase in the prevalence of psychiatric disorders before the diagnosis implies that some of these psychiatric disorders might actually have been prodromal symptoms of Alzheimer's disease. This underlines the importance of proper differential diagnostics of Alzheimer's disease. Further, the findings also highlight the importance of using an appropriate time window when assessing the risk factors of neurodegenerative diseases with a long onset period. Otherwise the identified "risk factors" may actually be manifestations of the neurodegenerative disease.

It should also be acknowledged that although psychiatric disorders diagnosed 10-40 years before Alzheimer's disease were not related to a higher risk, the life expectancy of persons with psychiatric disorders was, and is still decreased. Thus, those persons with psychiatric disorders who lived long enough to develop Alzheimer's disease were a selected sample of all persons with psychiatric disorders.

The study was conducted in the MEDALZ-2005 cohort which included all Finnish community dwellers with clinically verified Alzheimer's disease at the end of 2005 and their age, sex and region of residence matched controls (N of case-control pairs 27,948). History of psychiatric disorders since 1972 was extracted from the Finnish Hospital Discharge Register. Chronic disorders and substance abuse were taken into account.

Article: Hospital-treated mental and behavioral disorders and risk of Alzheimer's disease: A nationwide nested case-control study, V. Tapiainen, S. Hartikainen, H. Taipale, J. Tiihonen, A.-M. Tolppanen, European Psychiatry, doi: 10.1016/j.eurpsy.2017.02.486, published online March 2017.

SuperAger brains shrink more slowly than peers' brains

Cortex of super-aged brain deteriorated much slower than average elderly brain over time.

Donald Tenbrunsel is 89 years old, but he is just as likely to talk to you about Chance the Rapper as reminisce about Frank Sinatra.

The highly engaged and delightful conversationalist, who reads, volunteers and routinely researches questions on the Internet, is part of a new path-breaking Northwestern Medicine study that shows that SuperAgers' brains shrink much slower than their age-matched peers, resulting in a greater resistance to "typical" memory loss and dementia.

Over the course of the 18-month study, normal agers lost volume in the cortex twice as fast as SuperAgers, a rare group of people aged 80 and above whose memories are as sharp as those of healthy persons decades younger.

"Increasing age is often accompanied by 'typical' cognitive decline or, in some cases, more severe cognitive decline called dementia," said first author Amanda Cook, a clinical neuropsychology doctoral student in the laboratory of Emily Rogalski and Sandra Weintraub. "SuperAgers suggest that age-related cognitive decline is not inevitable."

The study was published in JAMA. Senior author Emily Rogalski will present the findings at the 2017 Cognitive Aging Summit in Bethesda, Maryland, April 6.

SuperAger Tenbrunsel, who lives with his daughter's family, is intent on being a good conversationalist with his three grandchildren.

"I have to adapt to that kind of life," Tenbrunsel said. "They don't know much about Frank Sinatra or Franklin Delano Roosevelt, so I have to keep saying, 'Is the Chance the Rapper coming this week or is it Taylor Swift?'"

The researchers already knew SuperAgers' brains tended to retain more brain volume and typically don't show the same wear-and-tear as normal agers.

"For this study we explored whether SuperAgers' brains were on a different trajectory of decline," said Rogalski, associate professor at the Cognitive Neurology and Alzheimer's Disease Center (CNADC) at Northwestern University Feinberg School of Medicine. "We found that SuperAgers are resistant to the normal rate of decline that we see in average elderly, and they're managing to strike a balance between life span and health span, really living well and enjoying their later years of life."

Using magnetic resonance imaging (MRI), the scientists measured the thickness of the cortex in 24 SuperAgers and 12 same-age, educationally and cognitive average peers (control group) to determine the approximate health of the brain over 18 months. The annual percent decline in thickness between the first and second visit for the SuperAgers was 1.06 and 2.24 for the control group.

Previous research showed that SuperAgers have a thicker cortex than those who age normally. By studying what makes SuperAgers unique, the scientists said they hope to undercover biological factors, such as the reduced cortical brain atrophy demonstrated here, that might contribute to the maintenance of memory ability in advanced age.

SuperAger research at Northwestern is flipping the traditional approach to Alzheimer's research of focusing on brains that are underperforming to instead focusing on outperforming brains.

"Sometimes it's useful to turn a complex problem on its head and look from a different vantage point," Rogalski said. "The SuperAging program studies people at the opposite end of the spectrum: those with unexpectedly high memory performance for their age."

Other Northwestern authors on the study include Jaiashre Sridhar, Daniel Ohm, Alfred Rademaker, Dr. M. Marsel Mesulam and Sandra Weintraub.

The research was funded by grants from the National Institutes of Health, including R01AG045571 and P30 AG13854 from the National Institute on Aging, T32 NS047987 from the National Institute of Neurological Disorders and Stroke, as well as the Davee Foundation.

Article: Rates of Cortical Atrophy in Adults 80 Years and Older With Superior vs Average Episodic Memory, Amanda H. Cook, MA; Jaiashre Sridhar, MS; Daniel Ohm, BS; Alfred Rademaker, PhD; M.-Marsel Mesulam, MD; Sandra Weintraub, PhD; Emily Rogalski, PhD, JAMA, doi: 10.1001/jama.2017.0627, published 4 April 2017.

Neurological diseases cost the U.S. nearly $800 billion per year

A new paper published in the Annals of Neurology reports the most common neurological diseases pose a serious annual financial burden for the nation.

The report notes that the current estimated annual cost to American society of just nine of the most common neurological diseases is staggering, totaling $789 billion in 2014 dollars. These conditions include Alzheimer's disease and other dementias, low back pain, stroke, traumatic brain injury, migraine, epilepsy, multiple sclerosis, spinal cord injury, and Parkinson's disease.

Costs will increase even further over the coming years as the elderly segment of the population nearly doubles between 2011 and 2050. The costs of dementia and stroke alone are projected to total over $600 billion by 2030. The article provides an action plan for reducing this burden through infrastructure investment in neurological research and enhanced clinical management of neurological disorders.

"The findings of this report are a wake-up call for the nation, as we are facing an already incredible financial burden that is going to rapidly worsen in the coming years," said lead author Dr. Clifton Gooch. "Although society continues to reap the benefits of the dramatic research investments in heart disease and cancer over the last few decades, similar levels of investment are required to fund neuroscience research focused on curing devastating neurological diseases such as stroke and Alzheimer's, both to help our patients and also to avoid costs so large they could destabilize the entire health care system and the national economy."

Article: The Burden of Neurological Disease in the United States: A Summary Report and Call to Action, Clifton L. Gooch MD, Etienne Pracht PhD and Amy R. Borenstein, PhD, Annals of Neurology, doi: 10.1002/ana.24897, published online 15 February 2017.