Category Archives: Longevity

Living in Disadvantaged Neighborhoods Increases Risk for Brain Atrophy

July 1, 2020

Continuous scientific efforts contribute to the emergence of new information revealing the intricate complexities of neurological functions and their surprising connection to a wide range of external factors. Protecting neurological function can be made possible through the growing identification of risk factors for neurodegeneration during the aging process and can help inform new preventative protocols for dementia and cognitive decline.

The latest data suggest an association between living in a disadvantaged neighborhood and developing brain atrophy, or experiencing a decrease in the number of brain cells or connections over time. Neighborhood disadvantage functions as a social determinant of health, reflecting the education, income, employment, and quality of housing within a particular geographic area. As brain atrophy typically predisposes individuals to dementia and cognitive decline, this finding has significant implications for protecting cognitive function as individuals age.

Impact of Neighborhood on Neurological Health

Examining the impact of neighborhood socioeconomic disadvantage on brain volume in a cognitively unimpaired population, researchers conducted a study of over 950 individuals without a history of cognitive impairment in Wisconsin. In their cross-sectional study, the research team evaluated participants living in the most socioeconomically disadvantaged neighborhoods using data from the Wisconsin Registry for Alzheimer’s Prevention and the Wisconsin Alzheimer’s Disease Research Center to assess T1-weighted structural MRI scans.

At the beginning of the trial, participants were not cognitively impaired based on the National Institute on Aging-Alzheimer’s Association diagnostic criteria, however, the cohort was enriched for Alzheimer’s disease risk based on a family history of dementia.

Led by Amy J.H. Kind, MD, PhD from the University of Wisconsin, researchers calculated total hippocampal volume by combining both left and right measurements and based total brain tissue volume measures on total white and gray matter volumes. Additionally, they computed both the Area Deprivation Index – a geospatially determined index of neighborhood-level disadvantage – and cardiovascular disease risk indices for each participant. Linear regression models were used to test the relationships between neighborhood disadvantage and hippocampal and total brain tissue volume – as assessed by magnetic resonance imaging.

Neighborhood Disadvantage Linked to Loss of Brain Volume

Earlier this year, the team published their findings online in JAMA Neurology which reveal that living in socioeconomically disadvantaged neighborhoods was associated with markedly decreased hippocampal and total brain tissue volume. Other middle-aged and older adults who lived in areas with lesser disadvantage experienced comparatively lower risks of both neurological outcomes. Researchers found that individuals living in the most disadvantaged neighborhoods experienced a mean of 7 years of age-related hippocampal atrophy.

Furthermore, they also noted that men living in these neighborhoods experienced a higher risk for brain atrophy than women, although the reasons for this correlation remain unknown.

Cardiovascular risk was found to mediate the association in the case of total cerebral volume, indicating that neighborhood-level disadvantage may be associated with the two neurological outcomes via distinct biological pathways.

However, investigators acknowledged potential limitations of the trial which included the “enriched risk study cohort” – including older participants and those with a family history of dementia. They note that this population “might be particularly vulnerable to the deleterious effects of neighborhood-level disadvantage on the hippocampus.” In addition, the study’s findings reveal associations and not causality due to its cross-sectional, observational nature and require further validation.

Different from the implications of individual-level socioeconomic status on neurological function, this is the first study to reveal a robust association between neighborhood-level disadvantage and hippocampal volume, according to researchers. The latest findings indicate that neighborhood disadvantage may be associated with brain tissue volume throughout the aging process even in the absence of clinical cognitive impairment.

These results may suggest new population markers to leverage in future research studies; neighborhood-level disadvantage could be considered in clinical decision-making or used to guide public health efforts that support healthy brain aging in such geographic areas.

Brain Health Benefits of Yoga Practice

June 25, 2020

Despite being an exercise performed for many centuries in Eastern cultures, yoga has become increasingly popular over the past few decades among the Western population and alongside it, an exponential increase in research. People are drawn to the practice due to its multitude of mental and physical benefits, which include relaxation, muscle stretching, and an increased feeling of mindfulness. The health benefits of the physical exercise have been well established, yet there is a lack of research concerning the impact of yoga practice on the brain.

Today, yoga is the most popular form of complementary therapy practiced by over 13 million adults, with 58% of adults citing maintenance of health and well-being as their reason for practice per data reported by the National Center for Complementary and Integrative Health (NCCIH).

Recently, yoga has gained increased attention in the scientific community as well, as a research area of interest among exercise neuroscientists due to its promising potential therapeutic benefits with potential to combat widespread increases in the prevalence of age-related neurodegenerative diseases. Few studies have investigated the benefits of yoga on brain health yet recent research from the University of Illinois at Urbana-Champaign aims to analyze current literature related to yoga practice and its documented positive effects on brain structure and function.

Yoga and the Brain 

The team of researchers analyzed 11 studies of the relationships between yoga and brain health including the impact of yoga practice on brain structures, function, and cerebral blood flow. Of those, 5 trials engaged participants with no prior yoga experience in one or more yoga sessions per week over a period of 10 to 24 weeks to compare brain health before and after the intervention. Meanwhile, the remaining studies measured differences in brain health between participants who regularly practiced yoga and those who did not.

To determine variations in brain structure and health, each study utilized brain-imaging technologies including MRI, functional MRI, or single-photon emission computerized tomography to analyze the impact of Hatha yoga practice – which incorporates body movements, meditation, and breathing exercises.

Positive Neuroprotective Effects

Overall, researchers found that the studies reported a beneficial effect of yoga practice on both the structure and functioning of the hippocampus, amygdala, prefrontal cortex, cingulate cortex, and brain networks. As many of these regions are known to be related to age-related atrophy, the early evidence is promising and implicates that regular yoga practice could work to mitigate age-related and neurodegenerative diseases.

“For example, we see increases in the volume of the hippocampus with yoga practice,” lead author Neha Gothe from the University of Illinois said. “Many studies looking at the brain effects of aerobic exercise have shown a similar increase in hippocampus size over time.”

In addition, the review of the studies found that brain changes related to yoga practice were linked to improved cognitive performance and measures of emotional regulation.

Changes in Brain Structure

According to Gothe and her colleague Jessica Damoiseaux psychology professor at Wayne State University, many of the studies were exploratory and not conclusive. Despite this, the researchers suggest their findings underline important brain changes associated with regular yoga practice, including amygdala growth which may be directly related to improved emotional regulation in yoga practitioners.

“The prefrontal cortex, cingulate cortex and brain networks such as the default mode network also tend to be larger or more efficient in those who regularly practice yoga,” Damoiseaux explains. “Like the amygdala, the cingulate cortex is part of the limbic system, a circuit of structures that plays a key role in emotional regulation, learning, and memory.”

Regular yoga practice may help improve the cortisol stress response; researchers found that participants who practiced yoga for eight weeks had an attenuated cortisol response which also contributed to improved testing performance in cases of decision-making, task-switching, and attention span. Overall, researchers believe that the positive implications of yoga on brain structures and emotional regulation improve total brain functioning and thus, may have neuroprotective effects.

Not only does a regular yoga practice have well-documented physical health benefits, but it appears to also promote healthy brain function. However, researchers caution that more research is needed in this field to uncover the mechanisms underlying the evident brain changes, recommending large intervention studies that engage participants in yoga practice for long periods of time and allow for comparisons with other forms of exercise.

“The science is pointing to yoga being beneficial for healthy brain function, but we need more rigorous and well-controlled intervention studies to confirm these initial findings,” Damoiseaux concludes.

Changes in Gut Microbiome Associated with MS Treatment

March 24, 2020

As the most widespread disabling neurological condition in young adults, multiple sclerosis (MS) affects approximately 1 million people in the United States and up to 2.3 million across the globe. Although researchers have not yet discovered the underlying causes of the condition or the reasons behind its unpredictable progression, there is an increased focus on the role of the gut microbiome in its development.

Prior research linking gut flora and multiple sclerosis has shown differences in the types of gut bacteria found in individuals with multiple sclerosis (MS). Patients with MS tend to have more archea –  a microbe responsible for inflammation – and less butyricimonas – a microbe with anti-inflammatory properties – compared with individuals without the condition.

New research implicates that patients with multiple sclerosis exhibit changes in gut bacteria composition after being treated with the disease-modifying drug ocrelizumab (Ocrevus).

Effect of Medication on Gut Microbiome

Disease-modifying medications tackle MS by depleting B cells, leading researchers to hypothesize that ocrelizumab could normalize the phenotype and metabolic profiles of gut bacteria thereby promoting an anti-inflammatory immune environment. As part of the ongoing trial, the research team is enrolling patients with new-onset multiple sclerosis and evaluating longitudinal samples of paired blood and stool with advanced techniques – including IgA-Seq, a novel tool that allows the differentiation of immune-reactive bacteria from IgA-uncoated bacteria.

Changes in Gut Bacteria

According to preliminary findings from the ongoing study, the normalization of certain components of the fecal microbiome in MS patients occurred at 1 month after ocrelizumab treatment, compared with baseline measurements. The team’s initial results are based on a cohort of 8 patients with MS and 5 control group participants.

Several members of the MS group showed very high IgA-coated indices for selected bacteria in the butyrate-producing Lachnospiraceae family at baseline. Following ocrelizumab treatment, these patients showed a reduction in the IgA coating index for butyrate producers. Furthermore, butyrate was significantly decreased at baseline in the MS group compared with levels found in the healthy control group. However, these changes did not last and the difference in butyrate levels dissipated after treatment was ceased. No differences were observed in acetate and propionate values.

Implications of Bacteria Changes

“Our data suggest that a subset of butyrate-producing gut bacteria is recognized as pathogenic by the immune system of untreated MS patients, based on high levels of IgA coating,” the researchers told Medscape Medical News, “This phenomenon could impact the amount of butyrate produced and affect the differentiation of circulating immune cells.”

The reduction of the IgA coating index of butyrate-producing bacteria as a result of ocrelizumab treatment points to its potentially significant role in the efficacy of B-cell depletion in MS patients. “The data also suggest that “changes in the gut microbiota may comprise part of the mechanism of action for a variety of MS disease-modifying therapies, including ocrelizumab,” lead author Erin Longbrake, MD, PhD told Medscape Medical News.

Due to the small scale of the study, its results are difficult to generalize; however the preliminary findings add to a growing body of evidence supporting the critical relationship between the gut microbiome and multiple sclerosis pathology. The research team is currently enrolling additional participants to investigate this connection further and plans on expanding its analysis to include long-amplicon sequencing and metabolomic analysis.

With about 200 new cases of multiple sclerosis diagnosed per day in the United States, there is an acute need for a better understanding of its underlying mechanisms. Identifying how these changes in the gut microbiome occur and improving the understanding of the implications of pharmacologic therapies could lead to the development of more targeted, personalized interventions aimed toward correcting specific pathologic modifications.