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Life expectancy climbs worldwide but people spend more years living with illness and disability

Life expectancy at birth, both sexes, 2013 (credit: Institute for Health Metrics and Evaluation)

The good news: as for 2013, global life expectancy for people in 188 countries has risen 6.2 years since 1990 (65.3 to 71.5). The bad news: healthy life expectancy (HALE) at birth rose by only 5.4 years (56.9 to 62.3), due to fatal and nonfatal ailments (interactive visualization by country here).

In other words, people are living more years with illness and disability. Ischemic heart disease, lower respiratory infections, and stroke cause the most health loss around the world.

That’s according to a study published in the medical journal The Lancet on August 27, conducted by an international consortium of researchers working on the Global Burden of Disease study, led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.

“The world has made great progress in health, but now the challenge is to invest in finding more effective ways of preventing or treating the major causes of illness and disability,” said Professor Theo Vos of IHME, the study’s lead author.

For dozens of countries — including Botswana, Belize, and Syria — healthy life expectancy in 2013 was not significantly higher than in 1990. In some of those countries, including South Africa, Paraguay, and Belarus, healthy life expectancy has actually dropped (by as much as 10 years) since 1990.

Causes of health loss

The fastest-growing global cause of health loss between 1990 and 2013 was HIV/AIDS, which increased by 341.5%. But this dramatic rise masks progress in recent years; since 2005, health loss due to HIV/AIDS has diminished by 23.9% because of global focus on the disease. Ischemic heart disease, stroke, low back and neck pain, road injuries, and COPD have also caused an increasing amount of health loss since 1990.The impact of other ailments, such as diarrheal diseases, neonatal preterm birth complications, and lower respiratory infections, has significantly declined.

Across countries, patterns of health loss vary widely. The countries with the highest rates of DALYs are among the poorest in the world, and include several in sub-Saharan Africa: Lesotho, Swaziland, Central African Republic, Guinea-Bissau, and Zimbabwe. Countries with the lowest rates of health loss include Italy, Spain, Norway, Switzerland, and Israel.

The number of DALYs due to communicable, maternal, neonatal, and nutritional disorders has declined steadily, from 1.19 billion in 1990 to 769.3 million in 2013, while DALYs from non-communicable diseases have increased steadily, rising from 1.08 billion to 1.43 billion over the same period.

Ethiopia: a case study in progress

Ethiopia is one of several countries that have been rising to the challenge to ensure that people live lives that are both longer and healthier. In 1990, Ethiopians could expect to live 40.8 healthy years. But by 2013, the country saw an increase in healthy life expectancy of 13.5 years — more than double the global average — to 54.3 years.

“Ethiopia has made impressive gains in health over the past two decades, with significant decreases in rates of diarrheal disease, lower respiratory infection, and neonatal disorders,” said Dr. Tariku Jibat Beyene of Addis Ababa University. “But ailments such as heart disease, COPD, and stroke are causing an increasing amount of health loss. We must remain vigilant in addressing this new reality of Ethiopian health.”

Countries with highest healthy life expectancy, both sexes, 2013

1 Japan
2 Singapore
3 Andorra
4 Iceland
5 Cyprus
6 Israel
7 France
8 Italy
9 South Korea
10 Canada

Countries with lowest healthy life expectancy, both sexes, 2013

1 Lesotho
2 Swaziland
3 Central African Republic
4 Guinea-Bissau
5 Zimbabwe
6 Mozambique
7 Afghanistan
8 Chad
9 South Sudan
10 Zambia

Leading causes of DALYs or health loss globally for both sexes, 2013

1 Ischemic heart disease
2 Lower respiratory infection
3 Stroke
4 Low back and neck pain
5 Road injuries
6 Diarrheal diseases
7 Chronic obstructive pulmonary disease
8 Neonatal preterm birth complications
9 HIV/AIDS
10 Malaria

Abstract of Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990–2013: quantifying the epidemiological transition

Background: The Global Burden of Disease Study 2013 (GBD 2013) aims to bring together all available epidemiological data using a coherent measurement framework, standardised estimation methods, and transparent data sources to enable comparisons of health loss over time and across causes, age–sex groups, and countries. The GBD can be used to generate summary measures such as disability-adjusted life-years (DALYs) and healthy life expectancy (HALE) that make possible comparative assessments of broad epidemiological patterns across countries and time. These summary measures can also be used to quantify the component of variation in epidemiology that is related to sociodemographic development.

Methods: We used the published GBD 2013 data for age-specific mortality, years of life lost due to premature mortality (YLLs), and years lived with disability (YLDs) to calculate DALYs and HALE for 1990, 1995, 2000, 2005, 2010, and 2013 for 188 countries. We calculated HALE using the Sullivan method; 95% uncertainty intervals (UIs) represent uncertainty in age-specific death rates and YLDs per person for each country, age, sex, and year. We estimated DALYs for 306 causes for each country as the sum of YLLs and YLDs; 95% UIs represent uncertainty in YLL and YLD rates. We quantified patterns of the epidemiological transition with a composite indicator of sociodemographic status, which we constructed from income per person, average years of schooling after age 15 years, and the total fertility rate and mean age of the population. We applied hierarchical regression to DALY rates by cause across countries to decompose variance related to the sociodemographic status variable, country, and time.

Findings: Worldwide, from 1990 to 2013, life expectancy at birth rose by 6·2 years (95% UI 5·6–6·6), from 65·3 years (65·0–65·6) in 1990 to 71·5 years (71·0–71·9) in 2013, HALE at birth rose by 5·4 years (4·9–5·8), from 56·9 years (54·5–59·1) to 62·3 years (59·7–64·8), total DALYs fell by 3·6% (0·3–7·4), and age-standardised DALY rates per 100 000 people fell by 26·7% (24·6–29·1). For communicable, maternal, neonatal, and nutritional disorders, global DALY numbers, crude rates, and age-standardised rates have all declined between 1990 and 2013, whereas for non–communicable diseases, global DALYs have been increasing, DALY rates have remained nearly constant, and age-standardised DALY rates declined during the same period. From 2005 to 2013, the number of DALYs increased for most specific non-communicable diseases, including cardiovascular diseases and neoplasms, in addition to dengue, food-borne trematodes, and leishmaniasis; DALYs decreased for nearly all other causes. By 2013, the five leading causes of DALYs were ischaemic heart disease, lower respiratory infections, cerebrovascular disease, low back and neck pain, and road injuries. Sociodemographic status explained more than 50% of the variance between countries and over time for diarrhoea, lower respiratory infections, and other common infectious diseases; maternal disorders; neonatal disorders; nutritional deficiencies; other communicable, maternal, neonatal, and nutritional diseases; musculoskeletal disorders; and other non-communicable diseases. However, sociodemographic status explained less than 10% of the variance in DALY rates for cardiovascular diseases; chronic respiratory diseases; cirrhosis; diabetes, urogenital, blood, and endocrine diseases; unintentional injuries; and self-harm and interpersonal violence. Predictably, increased sociodemographic status was associated with a shift in burden from YLLs to YLDs, driven by declines in YLLs and increases in YLDs from musculoskeletal disorders, neurological disorders, and mental and substance use disorders. In most country-specific estimates, the increase in life expectancy was greater than that in HALE. Leading causes of DALYs are highly variable across countries.

Interpretation: Global health is improving. Population growth and ageing have driven up numbers of DALYs, but crude rates have remained relatively constant, showing that progress in health does not mean fewer demands on health systems. The notion of an epidemiological transition—in which increasing sociodemographic status brings structured change in disease burden—is useful, but there is tremendous variation in burden of disease that is not associated with sociodemographic status. This further underscores the need for country-specific assessments of DALYs and HALE to appropriately inform health policy decisions and attendant actions.

Funding: Bill & Melinda Gates Foundation.

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Lack of sleep connected to catching a cold, new research confirms

(Credit: iStock)

If you sleep six hours a night or less a night, you are 4.2 times more likely to catch a cold (five hours or less, 4.5 times more likely) compared to those who sleep more than seven hours in a night.

That’s the finding of a study by  Carnegie Mellon University’s Sheldon Cohen, the Robert E. Doherty University Professor of Psychology in the Dietrich College of Humanities and Social Sciences, and researchers from UC San Francisco and the University of Pittsburgh Medical Center.

Published in the journal Sleep, the researchers used objective sleep measures. For the study, 164 adults underwent two months of health screenings, interviews and questionnaires to establish baselines for factors like stress, temperament, and alcohol and cigarette use. The researchers also tracked their sleep patterns for seven days using a watch-like sensor that measured the duration and quality of sleep throughout the night.

Then, the participants were sequestered in a hotel, administered the cold virus via nasal drops and monitored for a week, collecting daily mucus samples to see if the virus had taken hold.

“Sleep goes beyond all the other factors that were measured,” Prather said. “It didn’t matter how old people were, their stress levels, their race, education or income. It didn’t matter if they were a smoker. With all those things taken into account, statistically sleep still carried the day and was an overwhelmingly strong predictor for susceptibility to the cold virus.”

Aric Prather, assistant professor of psychiatry at UCSF and lead author of the study, said the study shows the risks of chronic sleep loss better than typical experiments in which researchers artificially deprive subjects of sleep, because it is based on subjects’ normal sleep behavior. “This could be a typical week for someone during cold season,” he said.

Sleep should be treated as a crucial pillar of public health, along with diet and exercise, the researchers said.

Abstract of Behaviorally Assessed Sleep and Susceptibility to the Common Cold

Study Objectives:

Short sleep duration and poor sleep continuity have been implicated in the susceptibility to infectious illness. However, prior research has relied on subjective measures of sleep, which are subject to recall bias. The aim of this study was to determine whether sleep, measured behaviorally using wrist actigraphy, predicted cold incidence following experimental viral exposure.

Design, Measurements, and Results:

A total of 164 healthy men and women (age range, 18 to 55 y) volunteered for this study. Wrist actigraphy and sleep diaries assessed sleep duration and sleep continuity over 7 consecutive days. Participants were then quarantined and administered nasal drops containing the rhinovirus, and monitored over 5 days for the development of a clinical cold (defined by infection in the presence of objective signs of illness). Logistic regression analysis revealed that actigraphy- assessed shorter sleep duration was associated with an increased likelihood of development of a clinical cold. Specifically, those sleeping < 5 h (odds ratio [OR] = 4.50, 95% confidence interval [CI], 1.08–18.69) or sleeping between 5 to 6 h (OR = 4.24, 95% CI, 1.08–16.71) were at greater risk of developing the cold compared to those sleeping > 7 h per night; those sleeping 6.01 to 7 h were at no greater risk (OR = 1.66; 95% CI 0.40–6.95). This association was independent of prechallenge antibody levels, demographics, season of the year, body mass index, psychological variables, and health practices. Sleep fragmentation was unrelated to cold susceptibility. Other sleep variables obtained using diary and actigraphy were not strong predictors of cold susceptibility.

Conclusions:

Shorter sleep duration, measured behaviorally using actigraphy prior to viral exposure, was associated with increased susceptibility to the common cold.

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Older people in Germany and England getting smarter, but not fitter

(credit: iStock)

People over age 50 are scoring better on cognitive tests than people of the same age did in the past — a trend that could be linked to higher education rates and increased use of technology in our daily lives, according to a new study published in an open-access paper in the journal PLOS ONE. But the study also showed that average physical health of the older population has declined.

The study, by researchers at the International Institute for Applied Systems Analysis (IIASA) in Austria, relied on representative survey data from Germany that measured cognitive processing speed, physical fitness, and mental health in 2006 and again in 2012.

It found that cognitive test scores increased significantly within the six-year period (for men and women and at all ages from 50 to 90 years), while physical functioning and mental health declined, especially for low-educated men aged 50–64. The survey data was representative of the non-institutionalized German population, mentally and physically able to participate in the tests.

Cognition normally begins to decline with age, and is one key characteristic that demographers use to understand how different population groups age more successfully than others, according to IIASA population experts.

Changing lifestyles

Previous studies have found elderly people to be in increasingly good health — “younger” in many ways than previous generations at the same chronological age — with physical and cognitive measures all showing improvement over time. The new study is the first to show divergent trends over time between cognitive and physical function.

“We think that these divergent results can be explained by changing lifestyles,” says IIASA World Population Program researcher Nadia Steiber, author of the PLOS ONE study. “Life has become cognitively more demanding, with increasing use of communication and information technology also by older people, and people working longer in intellectually demanding jobs. At the same time, we are seeing a decline in physical activity and rising levels of obesity.”

A second study from IIASA population researchers, published last week in the journal Intelligence found similar results, suggesting that older people have also become smarter in England.

“On average, test scores of people aged 50+ today correspond to test scores from people 4–8 years younger and tested 6 years earlier,” says Valeria Bordone, a researcher at IIASA and the affiliated Wittgenstein Centre for Demography and Global Human Capital.

The studies both provide confirmation of the “Flynn effect” — a trend in rising performance in standard IQ tests from generation to generation. The studies show that changes in education levels in the population can explain part, but not all of the effect.

“We show for the first time that although compositional changes of the older population in terms of education partly explain the Flynn effect, the increasing use of modern technology such as computers and mobile phones in the first decade of the 2000s also contributes considerably to its explanation,” says Bordone.

The researchers note that while the findings apply to Germany and England, future research may provide evidence on other countries.


IIASA | Rethinking population aging

Abstract of Population Aging at Cross-Roads: Diverging Secular Trends in Average Cognitive Functioning and Physical Health in the Older Population of Germany

This paper uses individual-level data from the German Socio-Economic Panel to model trends in population health in terms of cognition, physical fitness, and mental health between 2006 and 2012. The focus is on the population aged 50–90. We use a repeated population-based cross-sectional design. As outcome measures, we use SF-12 measures of physical and mental health and the Symbol-Digit Test (SDT) that captures cognitive processing speed. In line with previous research we find a highly significant Flynn effect on cognition; i.e., SDT scores are higher among those who were tested more recently (at the same age). This result holds for men and women, all age groups, and across all levels of education. While we observe a secular improvement in terms of cognitive functioning, at the same time, average physical and mental health has declined. The decline in average physical health is shown to be stronger for men than for women and found to be strongest for low-educated, young-old men aged 50–64: the decline over the 6-year interval in average physical health is estimated to amount to about 0.37 SD, whereas average fluid cognition improved by about 0.29 SD. This pattern of results at the population-level (trends in average population health) stands in interesting contrast to the positive association of physical health and cognitive functioning at the individual-level. The findings underscore the multi-dimensionality of health and the aging process.

Abstract of Smarter every day: The deceleration of population ageing in terms of cognition

Cognitive decline correlates with age-associated health risks and has been shown to be a good predictor of future morbidity and mortality. Cognitive functioning can therefore be considered an important measure of differential aging across cohorts and population groups. Here, we investigate if and why individuals aged 50+ born into more recent cohorts perform better in terms of cognition than their counterparts of the same age born into earlier cohorts (Flynn effect). Based on two waves of English and German survey data, we show that cognitive test scores of participants aged 50+ in the later wave are higher compared with those of participants aged 50+ in the earlier wave. The mean scores in the later wave correspond to the mean scores in the earlier wave obtained by participants who were on average 4–8 years younger. The use of a repeat cross-sectional design overcomes potential bias from retest effects. We show for the first time that although compositional changes of the older population in terms of education partly explain the Flynn effect, the increasing use of modern technology (i.e., computers and mobile phones) in the first decade of the 2000s also contributes to its explanation.

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Omega-3 supplements fail to stem cognitive decline in the aged, NIH study shows

NIH study raises doubt about any benefits omega-3 and dietary supplements like these may have for cognitive decline (credit: Photo courtesy of NEI)

While some research suggests that a diet high in omega-3 fatty acids can protect brain health, a large clinical trial by researchers at the National Institutes of Health found that omega-3 supplements did not slow cognitive decline in older persons.

With 4,000 patients followed over a five-year period, the study is one of the largest and longest of its kind. It was published Tuesday August 25 in the Journal of the American Medical Association.

“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, M.D., deputy director of the Division of Epidemiology and Clinical Applications and deputy clinical director at the National Eye Institute (NEI), part of NIH.

Chew leads the Age-Related Eye Disease Study (AREDS), which was designed to investigate a combination of nutritional supplements for slowing age-related macular degeneration (AMD), a major cause of vision loss among older Americans. That study established that daily high doses of certain antioxidants and minerals — called the AREDS formulation — can help slow the progression to advanced AMD.

A later study, called AREDS2, tested the addition of omega-3 fatty acids to the AREDS formula. But the omega-3’s made no difference.

Omega-3 fatty acids are made by marine algae and are concentrated in fish oils; they are believed to be responsible for the health benefits associated with regularly eating fish, such as salmon, tuna, and halibut. Where studies have surveyed people on their dietary habits and health, they’ve found that regular consumption of fish is associated with lower rates of AMD, cardiovascular disease, and possibly dementia. “We’ve seen data that eating foods with omega-3 may have a benefit for eye, brain, and heart health,” Chew explained.

Cognitive function tests

With AREDS2, Dr. Chew and her team saw another opportunity to investigate the possible cognitive benefits of omega-3 supplements, she said. Participants were given cognitive function tests at the beginning of the study to establish a baseline, then at two and four years later.*

The tests, all validated and used in previous cognitive function studies, included eight parts designed to test immediate and delayed recall, attention and memory, and processing speed. The cognition scores of each subgroup decreased to a similar extent over time, indicating that no combination of nutritional supplements made a difference.

“The AREDS2 data add to our efforts to understand the relationship between dietary components and Alzheimer’s disease and cognitive decline,” said Lenore Launer, Ph.D. senior investigator in the Laboratory of Epidemiology and Population Science at the National Institute on Aging. “It may be, for example, that the timing of nutrients, or consuming them in a certain dietary pattern, has an impact. More research would be needed to see if dietary patterns or taking the supplements earlier in the development of diseases like Alzheimer’s would make a difference.”

*All participants had early or intermediate AMD. They were 72 years old on average and 58 percent were female. They were randomly assigned to one of the following groups:

  1. Placebo (an inert pill)
  2. Omega-3 [specifically docosahexaenoic acid (DHA, 350 mg) and eicosapentaenoic acid (650 mg)]
  3. Lutein and zeaxanthin (nutrients found in large amounts in green leafy vegetables)
  4. Omega-3 and Lutein/zeaxanthin

Because all participants were at risk for worsening of their AMD, they were also offered the original or a modified version of the AREDS formulation (without omega-3 or lutein/zeaxanthin).

Abstract of Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or Other Nutrient Supplementation on Cognitive Function

Importance  Observational data have suggested that high dietary intake of saturated fat and low intake of vegetables may be associated with increased risk of Alzheimer disease.

Objective  To test the effects of oral supplementation with nutrients on cognitive function.

Design, Setting, and Participants  In a double-masked randomized clinical trial (the Age-Related Eye Disease Study 2 [AREDS2]), retinal specialists in 82 US academic and community medical centers enrolled and observed participants who were at risk for developing late age-related macular degeneration (AMD) from October 2006 to December 2012. In addition to annual eye examinations, several validated cognitive function tests were administered via telephone by trained personnel at baseline and every 2 years during the 5-year study.

Interventions  Long-chain polyunsaturated fatty acids (LCPUFAs) (1 g) and/or lutein (10 mg)/zeaxanthin (2 mg) vs placebo were tested in a factorial design. All participants were also given varying combinations of vitamins C, E, beta carotene, and zinc.

Main Outcomes and Measures  The main outcome was the yearly change in composite scores determined from a battery of cognitive function tests from baseline. The analyses, which were adjusted for baseline age, sex, race, history of hypertension, education, cognitive score, and depression score, evaluated the differences in the composite score between the treated vs untreated groups. The composite score provided an overall score for the battery, ranging from −22 to 17, with higher scores representing better function.

Results  A total of 89% (3741/4203) of AREDS2 participants consented to the ancillary cognitive function study and 93.6% (3501/3741) underwent cognitive function testing. The mean (SD) age of the participants was 72.7 (7.7) years and 57.5% were women. There were no statistically significant differences in change of scores for participants randomized to receive supplements vs those who were not. The yearly change in the composite cognitive function score was −0.19 (99% CI, −0.25 to −0.13) for participants randomized to receive LCPUFAs vs −0.18 (99% CI, −0.24 to −0.12) for those randomized to no LCPUFAs (difference in yearly change, −0.03 [99% CI, −0.20 to 0.13]; P = .63). Similarly, the yearly change in the composite cognitive function score was −0.18 (99% CI, −0.24 to −0.11) for participants randomized to receive lutein/zeaxanthin vs −0.19 (99% CI, −0.25 to −0.13) for those randomized to not receive lutein/zeaxanthin (difference in yearly change, 0.03 [99% CI, −0.14 to 0.19]; P = .66). Analyses were also conducted to assess for potential interactions between LCPUFAs and lutein/zeaxanthin and none were found to be significant.

Conclusions and Relevance  Among older persons with AMD, oral supplementation with LCPUFAs or lutein/zeaxanthin had no statistically significant effect on cognitive function.

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Anti-aging effects (in mice) of a dietary supplement called alpha lipoic acid

Shortened telomeres, the protective caps at the ends of chromosomes (credit: NIGMS)

Scientists at Emory University School of Medicine have found that the dietary supplement alpha lipoic acid (ALA) can stimulate telomerase, the enzyme that lengthens telomeres, with positive effects in a mouse model of atherosclerosis.

In human cells, shortened telomeres, the protective caps at the ends of chromosomes, are a sign of aging and also contribute to aging.

The discovery highlights a potential avenue for the treatment for chronic diseases like atherosclerosis and diabetes.

The results were published in an open-access paper on Thursday, August 20 in Cell Reports.

“Alpha lipoic acid has an essential role in mitochondria, the energy-generating elements of the cell,” says senior author Wayne Alexander, MD, PhD, professor of medicine at Emory University School of Medicine. “It is widely available and has been called a ‘natural antioxidant.’ Yet ALA’s effects in human clinical studies have been a mixed bag.”

How ALA works in blood vessels

ALA appears to exert its effects against atherosclerosis by spurring the smooth muscle cells that surround blood vessels to make PGC1 (peroxisome proliferator-activated receptor gamma co-activator 1)-alpha.**

“The effects of chronic diseases such as atherosclerosis and diabetes on blood vessels can be traced back to telomere shortening,” Alexander says. “This means that treatments that can restore healthy telomeres have great potential.”

“What’s new here is that we show that PGC1-alpha is regulating telomerase, and that has real beneficial effects on cellular stress in a mouse model of atherosclerosis,” says Shiqin Xiong, PhD, instructor in the division of cardiology and first author of the paper.*

As a way to boost PGC1-alpha in cells more conveniently, Xiong and Alexander turned to alpha lipoic acid or ALA. ALA is a sulfur-containing fatty acid used to treat diabetic neuropathy in Germany, and has previously been shown to combat atherosclerosis in animal models.

Treating isolated smooth muscle cells with ALA for just one day could stimulate both PGC1-alpha and telomerase, the authors found. ALA’s effects on vascular smooth muscle cells could also be seen when it was injected into mice.

Other effects of ALA

Xiong and Alexander say they are now investigating the effects of ALA on other tissues in mice.

Telomerase is turned off in most healthy cell types and only becomes turned on when cells proliferate. Because telomerase is active in cancer cells and enables their continued growth, researchers have been concerned that stimulating telomerase in all cells might encourage cancer growth or have other adverse effects. They have not observed increased cancers in ALA-treated mice, but say more thorough investigation is needed to fully assess cancer risk.

“While ALA is present in many foods and its effects in animal models look promising, it may be problematic for clinical use because of its poor solubility, stability and bioavailability,” Xiong says. “We are designing new ways to formulate and deliver ALA-related compounds to resolve these issues.”

* Xiong and Alexander used a model of atherosclerosis where mice lacked the ApoE cholesterol processing gene and were fed a high-fat diet. In this model, mice also lacking PGC1-alpha have more advanced plaques in their blood vessels, but only in older animals, the authors show.

Consistent with the poorer state of their blood vessels, aortic cells from PGC1-alpha-disrupted mice had shorter telomeres and reduced telomerase activity. Having shortened telomeres led the smooth muscle cells to display more oxidative stress and damage to the rest of their DNA.

The authors show that introducing PGC1-alpha back into vascular smooth muscle cells lacking that gene with a gene-therapy adenovirus could restore telomerase activity and lengthen the cells’ telomeres.

** PGC1-alpha was already well known to scientists as controlling several aspects of how skeletal muscles respond to exercise. While the Emory researchers did not directly assess the effects of exercise in their experiments, their findings provide molecular clues to how exercise might slow the effects of aging or chronic disease in some cell types.

 

Abstract of PGC-1α Modulates Telomere Function and DNA Damage in Protecting against Aging-Related Chronic Diseases

Cellular senescence and organismal aging predispose age-related chronic diseases, such as neurodegenerative, metabolic, and cardiovascular disorders. These diseases emerge coincidentally from elevated oxidative/electrophilic stress, inflammation, mitochondrial dysfunction, DNA damage, and telomere dysfunction and shortening. Mechanistic linkages are incompletely understood. Here, we show that ablation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) accelerates vascular aging and atherosclerosis, coinciding with telomere dysfunction and shortening and DNA damage. PGC-1α deletion reduces expression and activity of telomerase reverse transcriptase (TERT) and increases p53 levels. Ectopic expression of PGC-1α coactivates TERT transcription and reverses telomere malfunction and DNA damage. Furthermore, alpha lipoic acid (ALA), a non-dispensable mitochondrial cofactor, upregulates PGC-1α-dependent TERT and the cytoprotective Nrf-2-mediated antioxidant/electrophile-responsive element (ARE/ERE) signaling cascades, and counteracts high-fat-diet-induced, age-dependent arteriopathy. These results illustrate the pivotal importance of PGC-1α in ameliorating senescence, aging, and associated chronic diseases, and may inform novel therapeutic approaches involving electrophilic specificity.

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‘Tricorder’-style handheld MouthLab detects patients’ vital signs, rivaling hospital devices

Johns Hopkins’ MouthLab is intended to collect vital signs and ultimately to also obtain noninvasive biochemical and biophysical measurements from the saliva and breath and estimate blood-sugar level. A prototype can obtain vital signs and an electrocardiogram (ECG). (credit: Gene Y. Fridman et al./Annals of Biomedical Engineering)

Inspired by the Star Trek tricorder, engineers and physicians at the Johns Hopkins University School of Medicine have developed a hand-held, battery-powered device called MouthLab that quickly picks up vital signs from a patient’s lips and fingertip.

Updated versions of the prototype could replace the bulky, restrictive monitors now used to display patients’ vital signs in hospitals and actually gather more data than is typically collected during a medical assessment in an ambulance, emergency room, doctor’s office, or patient’s home.

The MouthLab prototype’s measurements of heart rate, blood pressure, temperature, breathing rate, and blood oxygen from 52 volunteers compared well with vital signs measured by standard hospital monitors. The device also takes a basic electrocardiogram. The study was published in the September issue of the Annals of Biomedical Engineering.

Early warning for non-doctors

“We see it as a ‘check-engine’ light for humans,” says the device’s lead engineer, Gene Fridman, Ph.D., an assistant professor of biomedical engineering and of otolaryngology–head and neck surgery at Johns Hopkins. “It can be used by people without special training at home or in the field.” He expects the device may be able to detect early signs of medical emergencies, such as heart attacks, or avoid unnecessary ambulance trips and emergency room visits when a patient’s vital signs are good.

MouthLab hand-held unit with one attached mouthpiece, and two other mouthpieces (of the 25 total produced) on the left panel. The right panel shows the MouthLab being used by a subject with the data from the MouthLab sensors and vital signs estimates displayed on the laptop in real time. (credit: Gene Y. Fridman et al./Annals of Biomedical Engineering)

Because it monitors vital signs by mouth, future versions of the device will be able to detect chemical cues in blood, saliva, and breath that act as markers for serious health conditions. “We envision the detection of a wide range of disorders,” Fridman says, “from blood glucose levels for diabetics, to kidney failure, to oral, lung and breast cancers.”

Comparable to hospital devices, more compact

The MouthLab prototype consists of a small, flexible mouthpiece like those that scuba divers use, connected to a hand-held unit about the size of a telephone receiver. The mouthpiece holds a temperature sensor and a blood-volume sensor. The thumb pad on the hand-held unit has a miniaturized pulse oximeter for measuring blood oxygen level— a smaller version of the finger-gripping device used in hospitals. Other sensors measure breathing from the nose and mouth.

MouthLab also has three electrodes for ECGs — one on the thumb pad, one on the upper lip of the mouthpiece and one on the lower lip. These work about as well as the chest and ankle electrodes used on basic ECG equipment in many ambulances or clinics, says Fridman.

That ECG signal is also the basis for MouthLab’s novel way of recording blood pressure. When the signal shows the heart is contracting, the device optically measures changes in the volume of blood reaching the thumb and upper lip. Unique software converts the blood flow data into systolic and diastolic pressure readings. The study found that MouthLab blood-pressure readings effectively match those taken with standard, arm-squeezing cuffs.

The hand unit relays data by Wi-Fi to a nearby laptop or smart device, where graphs display real-time results. The next generation of the device will display its own data readouts with no need for a laptop, says Fridman. Ultimately, he explains, patients will be able to send results to their doctors via cellphone, and an app will let physicians add them to patients’ electronic medical records.

A 3-D printer made the parts for the prototype, “which looks a lot like a hand-held taser,” Fridman says. “Our final version will be smaller, more ergonomic, more user-friendly and faster. Our goal is to obtain all vital signs in under 10 seconds.”

Abstract of MouthLab: A Tricorder Concept Optimized for Rapid Medical Assessment

The goal of rapid medical assessment (RMA) is to estimate the general health of a patient during an emergency room or a doctor’s office visit, or even while the patient is at home. Currently the devices used during RMA are typically “all-in-one” vital signs monitors. They require time, effort and expertise to attach various sensors to the body. A device optimized for RMA should instead require little effort or expertise to operate and be able to rapidly obtain and consolidate as much information as possible. MouthLab is a battery powered hand-held device intended to acquire and evaluate many measurements such as non-invasive blood sugar, saliva and respiratory biochemistry. Our initial prototype acquires standard vital signs: pulse rate (PR), breathing rate (BR), temperature (T), blood oxygen saturation (SpO2), blood pressure (BP), and a three-lead electrocardiogram. In our clinical study we tested the device performance against the measurements obtained with a standard patient monitor. 52 people participated in the study. The measurement errors were as follows: PR: −1.7 ± 3.5 BPM, BR: 0.4 ± 2.4 BPM, T: −0.4 ± 1.24 °F, SpO2: −0.6 ± 1.7%. BP systolic: −1.8 ± 12 mmHg, BP diastolic: 0.6 ± 8 mmHg. We have shown that RMA can be easily performed non-invasively by patients with no prior training.

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Surprising results from brain and cognitive studies of a 93-year-old woman athelete

Olga Kotelko’s brain “does not look like a 90-plus-year-old” — Beckman Institute director Art Kramer

Brain scans and cognitive tests of Olga Kotelko, a 93-year-old Canadian track-and-field athlete with more than 30 world records in her age group, may support the potential beneficial effects of exercise on cognition in the “oldest old.”

In the summer of 2012, researchers at the Beckman Institute for Advanced Science and Technology at the University of Illinois invited her to visit for in-depth analysis of her brain. The resulting study, was reported in the journal Neurocase.

A retired teacher and mother of two, Kotelko started her athletic career late in life. She began with slow-pitch softball at age 65, and at 77 switched to track-and-field events, later enlisting the help of a coach. By the time of her death in 2014, she had won 750 gold medals in her age group in World Masters Athletics events, and had set new world records in the 100-meter, 200-meter, high jump, long jump, javelin, discus, shot put and hammer events.


Beckman Institute | Senior Olympian: 93-Year-Old Track Star Shows Physical & Mental Fitness

Lacking a peer group of reasonably healthy nonagenarians for comparison, the researchers decided to compare Kotelko with a group of 58 healthy, low-active women who were 60 to 78 years old.

“In our studies, we often collect data from adults who are between 60 and 80 years old, and we have trouble finding participants who are 75 to 80 and relatively healthy,” said U. of I. postdoctoral researcher Agnieszka Burzynska, who led the new analysis. As a result, very few studies have focused on the “oldest old,” she said.

“Although it is tough to generalize from a single study participant to other individuals, we felt very fortunate to have an opportunity to study the brain and cognition of such an exceptional individual,” said Beckman Institute director Art Kramer, an author of the new study.

Aging processes in the brain

The researchers wanted to determine whether Kotelko’s late-life athleticism had slowed — or perhaps even reversed — some of the processes of aging in her brain.

“In general, the brain shrinks with age,” Burzynska said. Fluid-filled spaces appear between the brain and the skull, and the ventricles enlarge, she said.

“The cortex, the outermost layer of cells where all of our thinking takes place, that also gets thinner,” she said. White matter tracts, which carry nerve signals between brain regions, tend to lose their structural and functional integrity over time. And the hippocampus, which is important to memory, usually shrinks with age, Burzynska said.

Previous studies have shown that regular aerobic exercise can enhance cognition and boost brain function in older adults, and can even increase the volume of specific brain regions like the hippocampus, Kramer said.

Surprising test results

In one long day at the lab, Kotelko submitted to an MRI brain scan, a cardiorespiratory fitness test on a treadmill, and cognitive tests. (All of the data are available at XNAT, a public repository; Kotelko and her daughter agreed to make her data public.) The women in the comparison group underwent the same tests and scans.

Afterwards, Kramer asked Olga if she was tired; she replied, “I rarely get tired.” “The decades-younger graduate students who tested her, however, looked exhausted.”

Kotelko’s brain offered some intriguing first clues about the potentially beneficial effects of her active lifestyle.

White-matter tracts remarkably intact. “Her brain did not seem to be, in general, very shrunken, and her ventricles did not seem to be enlarged,” Burzynska said. On the other hand, she had obvious signs of advanced aging in the white-matter tracts of some brain regions, Burzynska said.

“Olga had quite a lot white-matter hyperintensities, which are markers of unspecific white-matter damage,” she said. These are common in people over age 65, and tend to increase with age, she said.

As a whole, however, Kotelko’s white-matter tracts were remarkably intact — comparable to those of women decades younger, the researchers found. And the white-matter tracts in one region of her brain — the genu of the corpus callosum, which connects the right and left hemispheres at the very front of the brain — were in great shape, Burzynska said.

“Olga had the highest measure of white-matter integrity in that part of the brain, even higher than those younger females, which was very surprising,” she said. These white-matter tracts serve a region of the brain that is engaged in tasks known to decline fastest in aging, such as reasoning, planning and self-control, Burzynska said.

Better on cognitive test than other adults her own age. Kotelko performed worse on cognitive tests than the younger women, but better than other adults her own age who had been tested in an independent study. “She was quicker at responding to the cognitive tasks than other adults in their 90s,” Burzynska said. “And on memory, she was much better than they were.”

Hippocampus larger given her age. Her hippocampus was smaller than the younger participants, but larger than expected given her age, Burzynska said.

The new findings are only a very limited, first step toward calculating the effects of exercise on cognition in the oldest old, she said. “We have only one Olga and only at one time point, so it’s difficult to arrive at very solid conclusions,” Burzynska said.

“But I think it’s very exciting to see someone who is highly functioning at 93, possessing numerous world records in the athletic field and actually having very high integrity in a brain region that is very sensitive to aging. I hope it will encourage people that even as we age, our brains remain plastic. We have more and more evidence for that.”

The Robert Bosch Foundation and the National Institute on Aging at the National Institutes of Health supported this research, as did Abbott Nutrition, through the Center for Nutrition, Learning and Memory at the U. of I.

Kotelko biographer Bruce Grierson prompted researchers at the Beckman Institute to study Kotelko’s brain.

Abstract of White matter integrity, hippocampal volume, and cognitive performance of a world-famous nonagenarian track-and-field athlete

Physical activity (PA) and cardiorespiratory fitness (CRF) are associated with successful brain and cognitive aging. However, little is known about the effects of PA, CRF, and exercise on the brain in the oldest-old. Here we examined white matter (WM) integrity, measured as fractional anisotropy (FA) and WM hyperintensity (WMH) burden, and hippocampal (HIPP) volume of Olga Kotelko (1919–2014). Olga began training for competitions at age of 77 and as of June 2014 held over 30 world records in her age category in track-and-field. We found that Olga’s WMH burden was larger and the HIPP was smaller than in the reference sample (58 healthy low-active women 60–78 years old), and her FA was consistently lower in the regions overlapping with WMH. Olga’s FA in many normal-appearing WM regions, however, did not differ or was greater than in the reference sample. In particular, FA in her genu corpus callosum was higher than any FA value observed in the reference sample. We speculate that her relatively high FA may be related to both successful aging and the beneficial effects of exercise in old age. In addition, Olga had lower scores on memory, reasoning and speed tasks than the younger reference sample, but outperformed typical adults of age 90–95 on speed and memory. Together, our findings open the possibility of old-age benefits of increasing PA on WM microstructure and cognition despite age-related increase in WMH burden and HIPP shrinkage, and add to the still scarce neuroimaging data of the healthy oldest-old (>90 years) adults.

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Trans fats, but not saturated fats, linked to greater risk of death and heart disease

Which of these is a killer fat: cheese or margarine? (credit: Wikimedia Commons)

A study led by researchers at McMaster University has found that that trans fats are associated with greater risk of death and coronary heart disease, unlike saturated fats, which are also not associated with an increased risk of stroke or Type 2 diabetes.

The findings were published in an open-access paper August 12 by the British Medical Journal (BMJ).

Trans vs. saturated fats

“For years everyone has been advised to cut out fats,” said lead author Russell de Souza, an assistant professor in the Department of Clinical Epidemiology and Biostatistics with the Michael G. DeGroote School of Medicine. But there are different “fats.”

Saturated fats come mainly from animal products, such as butter, cows’ milk, meat, salmon, and egg yolks, and some plant products such as chocolate and palm oils. Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods.

Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear,” said de Souza. “That said, we aren’t advocating an increase of the allowance for saturated fats in dietary guidelines, as we don’t see evidence that higher limits would be specifically beneficial to health.”

Saturated fats are limited to less than 10 per cent of energy, and trans fats to less than one per cent of energy, to reduce risk of heart disease and stroke, guidelines cited in the BMJ paper (citations 14 to 19) currently recommend.

No cardio risk from saturated fats, unlike trans

Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease.

To help clarify these controversies, de Souza and colleagues analyzed the results of 50 observational studies assessing the association between saturated and/or trans fats and health outcomes in adults.

Study design and quality were taken into account to minimize bias, and the certainty of associations were assessed using a recognized scoring method developed at McMaster.

The team found no clear association between higher intake of saturated fats and death for any reason, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type 2 diabetes.

Killer fats

However, consumption of industrial trans fats was associated with a 34 per cent increase in death for any reason, a 28 per cent increased risk of CHD mortality, and a 21 per cent increase in the risk of CHD.

Inconsistencies in the studies analyzed meant that the researchers could not confirm an association between trans fats and type 2 diabetes. And, they found no clear association between trans fats and ischemic stroke.

The researchers stress that their results are based on observational studies, so no definitive conclusions can be drawn about cause and effect. However, the authors write that their analysis “confirms the findings of five previous systematic reviews of saturated and trans fats and CHD.”

De Souza, who is also a registered dietitian, added that dietary guidelines for saturated and trans fatty acids must carefully consider the effect of replacement foods.

“If we tell people to eat less saturated or trans fats, we need to offer a better choice. Unfortunately, in our review, we were not able to find as much evidence as we would have liked for a best replacement choice, but ours and other studies suggest replacing foods high in these fats — such as high-fat or processed meats and donuts — with vegetable oils, nuts, and whole grains.”

Abstract of Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies

Objective: To systematically review associations between intake of saturated fat and trans unsaturated fat and all cause mortality, cardiovascular disease (CVD) and associated mortality, coronary heart disease (CHD) and associated mortality, ischemic stroke, and type 2 diabetes.

Design: Systematic review and meta-analysis.

Data sources: Medline, Embase, Cochrane Central Registry of Controlled Trials, Evidence-Based Medicine Reviews, and CINAHL from inception to 1 May 2015, supplemented by bibliographies of retrieved articles and previous reviews.

Eligibility criteria for selecting studies: Observational studies reporting associations of saturated fat and/or trans unsaturated fat (total, industrially manufactured, or from ruminant animals) with all cause mortality, CHD/CVD mortality, total CHD, ischemic stroke, or type 2 diabetes.

Data extraction and synthesis: Two reviewers independently extracted data and assessed study risks of bias. Multivariable relative risks were pooled. Heterogeneity was assessed and quantified. Potential publication bias was assessed and subgroup analyses were undertaken. The GRADE approach was used to evaluate quality of evidence and certainty of conclusions.

Results: For saturated fat, three to 12 prospective cohort studies for each association were pooled (five to 17 comparisons with 90 501-339 090 participants). Saturated fat intake was not associated with all cause mortality (relative risk 0.99, 95% confidence interval 0.91 to 1.09), CVD mortality (0.97, 0.84 to 1.12), total CHD (1.06, 0.95 to 1.17), ischemic stroke (1.02, 0.90 to 1.15), or type 2 diabetes (0.95, 0.88 to 1.03). There was no convincing lack of association between saturated fat and CHD mortality (1.15, 0.97 to 1.36; P=0.10). For trans fats, one to six prospective cohort studies for each association were pooled (two to seven comparisons with 12 942-230 135 participants). Total trans fat intake was associated with all cause mortality (1.34, 1.16 to 1.56), CHD mortality (1.28, 1.09 to 1.50), and total CHD (1.21, 1.10 to 1.33) but not ischemic stroke (1.07, 0.88 to 1.28) or type 2 diabetes (1.10, 0.95 to 1.27). Industrial, but not ruminant, trans fats were associated with CHD mortality (1.18 (1.04 to 1.33) v 1.01 (0.71 to 1.43)) and CHD (1.42 (1.05 to 1.92) v0.93 (0.73 to 1.18)). Ruminant trans-palmitoleic acid was inversely associated with type 2 diabetes (0.58, 0.46 to 0.74). The certainty of associations between saturated fat and all outcomes was “very low.” The certainty of associations of trans fat with CHD outcomes was “moderate” and “very low” to “low” for other associations.

Conclusions: Saturated fats are not associated with all cause mortality, CVD, CHD, ischemic stroke, or type 2 diabetes, but the evidence is heterogeneous with methodological limitations. Trans fats are associated with all cause mortality, total CHD, and CHD mortality, probably because of higher levels of intake of industrial trans fats than ruminant trans fats. Dietary guidelines must carefully consider the health effects of recommendations for alternative macronutrients to replace trans fats and saturated fats.

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Study links aerobic fitness, thinner gray matter, and better math skills in kids

Cortical thickness regions of interest. Starred regions are areas in which higher-fit children showed decreased cortical thickness compared to lower-fit children. (credit: Laura Chaddock-Heyman et al./PLOS ONE)

A new study reveals that 9- and 10-year-old children who are aerobically fit tend to have significantly thinner gray matter than their “lower-fit” peers. Thinning of the outermost layer of brain cells in the cerebrum is associated with better mathematics performance, researchers report in an open-access paper in the journal PLOS ONE.

The study suggests, but does not prove, that cardiorespiratory fitness contributes to gray matter thinning — a normal process of child brain development. The study also offers the first evidence that fitness enhances math skills by aiding the development of brain structures that contribute to mathematics achievement.

“Gray-matter loss during child development is part of healthy maturation,” said University of Illinois postdoctoral researcher Laura Chaddock-Heyman, who led the research. “Gray-matter thinning is the sculpting of a fully formed, healthy brain. The theory is that the brain is pruning away unnecessary connections and strengthening useful connections.”

Previous studies have shown that gray-matter thinning is associated with better reasoning and thinking skills, Chaddock-Heyman said.

Role of aerobic fitness in math skills

“We show, for the first time, that aerobic fitness may play a role in this cortical thinning,” she said. “In particular, we find that higher-fit 9- and 10-year-olds show a decrease in gray-matter thickness in some areas known to change with development, specifically in the frontal, temporal and occipital lobes of the brain.”

The analysis included 48 children, all of whom had completed a maximal oxygen-uptake fitness test on a treadmill. Half of the children (the higher-fit kids) were at or above the 70th percentile for aerobic fitness, and half (the lower-fit kids) were at or below the 30th percentile. The researchers imaged the children’s brains using fMRI, and tested their math, reading, and spelling skills using the Wide Range Achievement Test-3, which correlates closely with academic achievement in these fields.

The team found differences in math skills and cortical brain structure between the higher-fit and lower-fit children: thinner gray matter corresponded to better math performance in the higher-fit kids. But they did not find significant fitness-associated differences in reading or spelling aptitude.

So why only math? “Successful mathematics problem solving is said to involve working memory, the ability to hold relevant information in mind for efficient and effective comprehension, as well as inhibition, the ability to ignore irrelevant information,” Chaddock-Heyman explained to KurzweilAI.

“Higher-fit children have shown superior performance on cognitive control tasks that challenge working memory and inhibitory control, relative to lower fit children. Other studies suggest superior performance on standardized tests of mathematics and reading in higher-fit children.”

“These findings arrive at an important time. Physical activity opportunities during the school day are being reduced or eliminated in response to mandates for increased academic time,” according to kinesiology and community health professor Charles H. Hillman. “Given that rates of physical inactivity are rising, there is an increased need to promote physical activity. Schools are the best institutions to implement such health behavior practices, due to the number of children they reach on a daily basis.”

“Future efforts should be directed toward determining whether these biomarkers predict performance on select academic subjects, as suggested in our study, or whether they serve as a more global index of overall school performance.”

The researchers next plan a longitudinal study of children participating in a physical activity training program. The goal is to establish additional neural biomarkers for scholastic success, based on a causal relationship between brain changes, changes in physical fitness, and changes in cognition, and to determine whether these biomarkers predict performance on select academic subjects (as in the current study), or overall school achievement .

The National Institute on Aging, the National Institute of Child Health and Human Development, and the National Institute of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health supported this research. The National Institute of Food and Agriculture at the U.S. Department of Agriculture also provided funding.

Abstract of The Role of Aerobic Fitness in Cortical Thickness and Mathematics Achievement in Preadolescent Children

Growing evidence suggests that aerobic fitness benefits the brain and cognition during childhood. The present study is the first to explore cortical brain structure of higher fit and lower fit 9- and 10-year-old children, and how aerobic fitness and cortical thickness relate to academic achievement. We demonstrate that higher fit children (>70th percentile VO2max) showed decreased gray matter thickness in superior frontal cortex, superior temporal areas, and lateral occipital cortex, coupled with better mathematics achievement, compared to lower fit children (<30th percentile VO2max). Furthermore, cortical gray matter thinning in anterior and superior frontal areas was associated with superior arithmetic performance. Together, these data add to our knowledge of the biological markers of school achievement, particularly mathematics achievement, and raise the possibility that individual differences in aerobic fitness play an important role in cortical gray matter thinning during brain maturation. The establishment of predictors of academic performance is key to helping educators focus on interventions to maximize learning and success across the lifespan.

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Biocompatible interfaces replace silicon and metal in neural prosthetic devices

Left: collagen; right: matrigel (credit: Wen Shen et al./Microsystems & Nanoengineering)

Researchers at the University of Georgia’s Regenerative Bioscience Center have developed a biocompatible implantable neural prosthetic device to replace silicon and noble metal in neural prosthetic devices. The goal is to avoid immune-system rejection, failures due to tissue strain, neurodegeneration, and decreased fidelity of recorded neural signals.

Implantable neural prosthetic devices in the brain have been around for almost two decades, helping people living with limb loss and spinal cord injury become more independent, for example. They are also used for deep brain stimulation and brain-controlled prosthetic devices. However, existing neural prosthetic devices suffer from immune-system rejection, and most are believed to eventually fail because of a mismatch between the soft brain tissue and the rigid devices.

The researchers used a combination of a two materials as structural support for neural electrodes.

Collagen. Its higher mechanical strength can support initial insertion while softening after implantation. Collagen is an extracellular matrix environment (ECM) protein that is critical in the formation of connective structures in tendons, organs, and basement membranes in the body and features long fibrils and 3D structures with high tensile strengths. The ECM is a collection of molecules secreted by cells that provides structural and biochemical support to surrounding cells.

Matrigel, a gelatinous ECM protein mixture resembling the complex extracellular neuronal environment, used to provide a more neuronal-compatible substrate.

A representative extracellular matrix-based implantable neural electrode device and an enlarged view of the electrode tip (credit: Wen Shen et al./Microsystems & Nanoengineering)

“This is not by any means the device that you’re going to implant into a patient,” said Karumbaiah, an assistant professor of animal and dairy science in the UGA College of Agricultural and Environmental Sciences. “This is proof of concept that extracellular matrix can be used to ensheathe a functioning electrode without the use of any other foreign or synthetic materials.”

The collaboration, led by Wen Shen and Mark Allen of the University of Pennsylvania, found that the extracellular matrix derived electrodes adapted to the mechanical properties of brain tissue and were capable of acquiring neural recordings from the brain cortex.

Currently, one out of every 190 Americans is living with limb loss, according to the National Institutes of Health. There is a significant burden in cost of care and quality of life for people suffering from this disability.

The research is described in an open-access paper in the journal Microsystems & Nanoengineering.

Abstract of Extracellular matrix-based intracortical microelectrodes: Toward a microfabricated neural interface based on natural materials

Extracellular matrix (ECM)-based implantable neural electrodes (NEs) were achieved using a microfabrication strategy on natural-substrate-based organic materials. The ECM-based design minimized the introduction of non-natural products into the brain. Further, it rendered the implants sufficiently rigid for penetration into the target brain region and allowed them subsequently to soften to match the elastic modulus of brain tissue upon exposure to physiological conditions, thereby reducing inflammatory strain fields in the tissue. Preliminary studies suggested that ECM-NEs produce a reduced inflammatory response compared with inorganic rigid and flexible approaches. In vivo intracortical recordings from the rat motor cortex illustrate one mode of use for these ECM-NEs.