UM research essential to global arctic animal migration archive

THE UNIVERSITY OF MONTANA

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IMAGE: A CARIBOU CALF FROLICS IN THE ARCHIVE STUDY AREA. view more 

CREDIT: PHOTO CREDIT TO KARSTEN HEUER

MISSOULA - Warmer winters, earlier springs, shrinking ice and increased human development - the Arctic is undergoing dramatic changes impacting native animals. And now, scientists can track the movements of thousands of Arctic and sub-Arctic animals over three decades with the new global Arctic Animal Movement Archive.

Researchers from around the world, including the University of Montana, have long observed the movements and behavior of animals in the Arctic, but have had difficulty discovering and accessing data. To solve the problem, an international team led by Sarah Davidson, data curator at the Max Planck Institute of Animal Behavior in Radolfzell, Germany, and Gil Bohrer, professor at Ohio State University, established the global data archive for studies of animal migration in the Arctic and sub-Arctic. It currently contains over 200 projects and movement data of more than 8,000 marine and terrestrial animals from 1991 to the present.

The archive, hosted on the Max Planck Institute's Movebank platform and funded by NASA, helps scientists share their knowledge and collaborate on questions on how animals are responding to a changing Arctic - particularly important because the Arctic region extends around the world. Researchers from more 100 universities, government agencies and conservation groups across 17 countries are involved in the archive.

UM contributors include Professor Mark Hebblewhite, graduate student Stephen Lewis and former postdoctoral researcher Eliezer Gurarie. Their research is part of Hebblewhite's funded NASA Arctic Boreal Vulnerability Experiment project that studies the effects of rapid climate change on wildlife in the Arctic, with a focus on caribou.

"UM has a long history, pioneered by researcher Steve Running, of understanding consequences of climate change to ecosystems, and this work builds on this important legacy in a region of the world undergoing some of the fastest rates of climate change, fires and impacts on people and nature," said Hebblewhite, who studies ungulate habitat ecology.

Three recent studies from the archive reveal large-scale patterns in the behaviors of golden eagles, bears, caribou, moose and wolves in the region and illustrate how the archive can be used to recognize larger ecosystem changes. The results were published Nov. 6 in an article in Science, one of world's premier scientific journals.

First, by comparing movements of more than 100 golden eagles from 1993 to 2017, researchers found that immature birds migrating north in the spring arrived earlier following mild winters. However, the arrival time of adults has remained rather constant, regardless of conditions at their breeding grounds, with consequences for nesting and chick survival.

The archive uses data from UM doctoral student Lewis, who is a wildlife biologist with the U.S. Fish and Wildlife Service Alaska Region, Division of Migratory Bird management. Lewis began studying the movements of golden eagles in 2012 to understand the costs of migration and carry-over effects of wintering in the contiguous U.S. for eagles born in Alaska. His data fit perfectly into the Arctic Animal Migration Archive and NASA's Arctic Boreal Vulnerability Experiment project, and he will continue to analyze eagle movement ecology at UM.

A second study of more than 900 female caribou from 2000 to 2017 found that more northern herds are giving birth earlier in the spring, while the calving dates of more southern populations have not shown the same change.

"Caribou are the Arctic's dominant large herbivore - an iconic symbol and crucial to Indigenous peoples for their food security and culture," Hebblewhite said. "Yet they are declining across the Arctic, and an obvious question is the role of climate change."

Hebblewhite said the research, which brought together an unparalleled dataset of nearly 1,000 GPS radio-collared caribou, showed a strong shift in calving dates across most of the region - and a potential contribution toward declining trends in the population.

A third analysis looking at the movement speeds of bears, caribou, moose and wolves from 1998 to 2019 showed that species respond differently to seasonal temperatures and winter snow conditions.

"Movement is central to animal survival in the harsh Arctic environment. Yet movement is costly, especially in the stark Arctic landscapes," Hebblewhite said. "Our work showed that increasing temperatures, especially in summer, were affecting movement rates of these large mammals, which could have energetic costs that stress these species. And changes in snow in the winter were also influencing wildlife movements - also in ways that could have population impacts."

In addition to the UM research and hundreds of studies already included in the archive, the resource is continually growing, as data are transmitted from animals in the field and more researchers join. Results should help detect changes in the behavior of animals and ultimately in the entire Arctic ecosystem.

"The Arctic is undergoing some of the most rapid climate change on the planet - upward of double the rates we are seeing here in Montana," Hebblewhite said. "We hope our collective work shows that the changes underway in the Arctic are real and strong and affecting almost all Arctic wildlife species, as well as the ecosystems and people who depend on them."

CAPTION

Two young golden eagles - one with a transmitter - nest on the Seward Peninsula, Alaska.

The Arctic Animal Movement Archive is online at https://www.movebank.org/cms/movebank-content/arctic-animal-movement-archive. The study, "Ecological insights from three decades of animal movement tracking across a changing Arctic," is online at https://science.sciencemag.org/content/370/6517/712.

Note: Movement is critical for animal life in the harsh Arctic. This GIF of Arctic Animal Movement Archive data shows the key role of the Arctic globally. https://umt.box.com/s/zf926rmtc8b68b9bokre6561sm8oaf6u.

 

Rivers melt Arctic ice, warming air and ocean

UNIVERSITY OF ALASKA FAIRBANKS

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IMAGE: WATER FROM CANADA'S MACKENZIE RIVER ENTERS THE BLUE ARCTIC OCEAN IN JULY 2012. WHITE AREAS IN THE TOP HALF OF THE PHOTO ARE LARGELY SEA ICE, WHILE THOSE BELOW ARE... view more 

CREDIT: PHOTO BY NASA EARTH OBSERVATORY

A new study shows that increased heat from Arctic rivers is melting sea ice in the Arctic Ocean and warming the atmosphere.

The study published this week in Science Advances was led by the Japan Agency for Marine-Earth Science and Technology, with contributing authors in the United States, United Arab Emirates, Finland and Canada.

According to the research, major Arctic rivers contribute significantly more heat to the Arctic Ocean than they did in 1980. River heat is responsible for up to 10% of the total sea ice loss that occurred from 1980 to 2015 over the shelf region of the Arctic Ocean. That melt is equivalent to about 120,000 square miles of 1-meter thick ice.

"If Alaska were covered by 1-meter thick ice, 20% of Alaska would be gone," explained Igor Polyakov, co-author and oceanographer at the University of Alaska Fairbanks' International Arctic Research Center and Finnish Meteorological Institute.

Rivers have the greatest impact during spring breakup. The warming water dumps into the ice-covered Arctic Ocean and spreads below the ice, decaying it. Once the sea ice melts, the warm water begins heating the atmosphere.

The research found that much more river heat energy enters the atmosphere than melts ice or heats the ocean. Since air is mobile, this means river heat can affect areas of the Arctic far from river deltas.

The impacts were most pronounced in the Siberian Arctic, where several large rivers flow onto the relatively shallow shelf region extending nearly 1,000 miles offshore. Canada's Mackenzie River is the only river large enough to contribute substantially to sea ice melt near Alaska, but the state's smaller rivers are also a source of heat.

Polyakov expects that rising global air temperatures will continue to warm Arctic rivers in the future. As rivers heat up, more heat will flow into the Arctic Ocean, melting more sea ice and accelerating Arctic warming.

Rivers are just one of many heat sources now warming the Arctic Ocean. The entire Arctic system is in an extremely anomalous state as global air temperatures rise and warm Atlantic and Pacific water enters the region, decaying sea ice even in the middle of winter. All these components work together, causing positive feedback loops that speed up warming in the Arctic.

"It's very alarming because all these changes are accelerating," said Polyakov. "The rapid changes are just incredible in the last decade or so."

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Authors of the paper include Hotaek Park, Eiji Watanabe, Youngwook Kim, Igor Polyakov, Kazuhiro Oshima, Xiangdong Zhang, John S. Kimball and Daqing Yang.

CAPTION

This diagram shows the relative amount of warming caused by Arctic rivers, with the sources of heat in orange and the heat sinks in turquoise. In spring, rivers flow into the Arctic Ocean, warming the water and melting sea ice, which in turn warms the atmosphere. A feedback occurs as the reflective ice disappears, allowing the dark ocean water to absorb more heat and melt more sea ice.

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Mystery of glacial lake floods solved

UNIVERSITY OF HAWAII AT MANOA

Research News

 

IMAGE: THE HOT WATER DRILL USED TO DRILL THROUGH THE GLACIER TO THE SUBGLACIAL LAKES. THE DRILL STEM IS HUNDREDS OF METERS BELOW IN THE ICE, SUSPENDED ON A RUBBER HOSE... view more 

CREDIT: ERIC GAIDOS

A long-standing mystery in the study of glaciers was recently --- and serendipitously -- solved by a team led by University of Hawai'i at Mānoa astrobiologist and earth scientist Eric Gaidos. Their findings were published this week in the journal Geophysical Research Letters.

The mystery involves floods or "jokulhlaups" that emerge suddenly and unpredictably from glaciers or ice caps like those in Iceland where volcanic heat melts the ice and water accumulates in lakes underneath the glaciers. Scientists have long studied the development of these floods, which are some of the largest on Earth.

"These floods may affect the motion of some glaciers and are a significant hazard in Iceland," said Gaidos, professor at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). "But the mechanism and timing of the initiation of these floods has not been understood."

Then, in June 2015, an unexpected series of events revealed how these floods start.

That summer, Gaidos and colleagues drilled a hole to one of the Icelandic lakes to study its microbial life. While collecting samples through the borehole, the team noticed a downwards current, like a bathtub drain, in the hole.

"The flow was so strong we nearly lost our sensors and sampling equipment into the hole," said Gaidos. "We surmised that we had accidentally connected a water mass inside the glacier to the lake beneath. That water mass was rapidly draining into the lake."

A few days later, after the team had left the glacier, the lake drained in a flood. Fortunately, the flood was small and Icelanders have an elaborate early-warning system on their rivers so no people were hurt, nor infrastructure damaged in this event, Gaidos assured.

The researchers used a computer model of the draining of the flow through the hole , and its effect on the lake, to show that this could have triggered the flood.

"We discovered that the glacier can contain smaller bodies of water above the lakes fed by summer melting," said Gaidos. "If this water body is hydraulically connected to the lake then the pressure in the lake rises and that allows water to start draining out underneath the glacier."

While the team made an artificial connection to the lake in 2015, natural connections can form when water from rain or melting snow accumulates in crevasses and the pressure eventually forces a crack through the glacier to the lake. This discovery provides a new understanding of how these floods can start and how this depends on weather and the season.

Collaborators in Iceland are continuing to research this phenomenon using radio echo-sounding to search for water bodies within the ice, as well as study the larger lake below it.

CAPTION

In June 2015, a team led by Gaidos used hot water to melt a hole through 250 meters of ice to sample a lake beneath a glacier in Iceland.

CAPTION

Illustration of the water movement that may have triggered the flood of June 2015 (arrows indicate flow direction): the subglacial lake, warmed to 4?C by geothermal input, the perched reservoir fed by summer melt through the firn layer, a water-filled system of crevasses and conduits (moulins), our borehole, and the outlet under the ice dam.

Underinsurance is growing, but HSAs aren't keeping up: BU study

BOSTON UNIVERSITY SCHOOL OF MEDICINE

Research News

 

High deductible health plans (HDHPs) have become much more common among all racial/ethnic and income groups, but the health savings accounts (HSAs) that make these plans potentially workable are far less common among Black, Hispanic, and lower-income enrollees--and the gap is growing.

That's according to a new Boston University School of Public Health (BUSPH) study published in the November issue of the journal Health Affairs, the first to examine these trends.

"This is a deeply concerning inequity that is getting worse and worse with each passing year," says study senior and corresponding author Dr. Megan B. Cole, assistant professor of health law, policy & management at BUSPH.

HDHPs offer lower premiums but leave patients potentially paying thousands of dollars out-of-pocket for healthcare before insurance kicks in, making it difficult or even impossible to afford needed care. So, HDHPs are often coupled with an HSA, where enrollees and their employers may contribute tax-exempt dollars to help pay for those out-of-pocket healthcare costs.

The first-of-its-kind study delves into the racial/ethnic and income-level trends in HDHP enrollment with and without HSAs, something missed by just looking at whether people have insurance or not.

"The ACA effectively reduced income and racial disparities in insurance coverage, but we don't know very much about disparities in underinsurance, or having coverage and not being able to pay for care," says study lead author Dr. Jacqueline Ellison, a postdoctoral researcher at Brown University School of Public Health.

According to the study's findings, "patients who would be the most likely to benefit from the financial protection of an HSA are increasingly the least likely to have an HSA, which further exacerbates the health inequities already faced by Black, Hispanic, and low-income adults," Cole says.

In a previous study, Cole and Ellison found that Black cancer survivors on HDHPs face more cost-related barriers to care than white cancer survivors on the same plans, including needing to skip a medication or delay a refill to save money, and not being able to see a specialist. The new study suggests racial disparities in having an HSA may be a big part of the reason.

"These consumer-oriented approaches to cost containment are disproportionately impacting marginalized populations that already experience financial barriers to care," Ellison says.

For the new study, Cole, Ellison, and co-author Paul Shafer, assistant professor of health law, policy & management at BUSPH, used data from the National Health Interview Survey from 2007-2018.

They found that HDHP enrollment skyrocketed during that time period, with similar rates of increase for all racial/ethnic and income groups. For example, among the lowest-income privately-insured adults, HDHP enrollment increased from 17% in 2007 to 40% by 2018.

"This means that by 2018, two in five low-income privately-insured adults often had to pay thousands of dollars in out of pocket costs before their health insurance would cover most of the cost, despite the fact that this represents a really substantial portion of their total income," Cole says. "While these lower-income patients may technically be insured, when they need any type of health care that is not otherwise exempt from cost-sharing, it is effectively like being uninsured."

HSAs were more common among high- and middle-income HDHP enrollees than low-income enrollees, and among white enrollees than Black and Hispanic enrollees--and these gaps widened between 2007 and 2018.

"In the short term, it's critical that we implement policies that not only tackle uninsurance but that also tackle underinsurance, particularly for low-income and racial/ethnic minority groups," Cole says. "This may include expanding Medicaid in current non-expansion states, expanding Marketplace cost-sharing subsidies to persons under the federal poverty line, and creating more substantial tax incentives for employers to subsidize cost-sharing for their lower-income employees."

But most importantly, Cole says, "we need policies that address the root causes of these inequities--namely, racism and structural inequalities, which lead to differential employment opportunities (meaning employers that are more versus less likely to contribute to an HSA), wealth, and abilities to save."

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About the Boston University School of Public Health

Founded in 1976, the Boston University School of Public Health is one of the top five ranked private schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations--especially the disadvantaged, underserved, and vulnerable--locally and globally.

Social distancing may have saved more than 59,000 U.S. Lives if implemented two weeks earlier

Differential effects of intervention timing on COVID-19 spread in the United States

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

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Implementing social distancing, business closures, and other non-pharmaceutical interventions (NPIs) in the U.S. two weeks sooner, during the earliest stages of the COVID-19 pandemic, may have prevented more than a million cases and saved more than 59,000 lives prior to May 3, 2020, when many state and local governments began relaxing restrictions, according to a new metapopulation modeling study. The results highlight the importance of quick and aggressive NPI implementation to counter transmission of the SARS-CoV-2 virus and could help inform efforts to control new surges in the U.S. and elsewhere in the world. Seeking to understand the impact of timing when implementing NPIs, Sen Pei and colleagues first built a metapopulation model of COVID-19 transmission in all 3,142 U.S. counties during the period spanning February 21 through May 3, 2020. They built the model using county-level data of confirmed cases and deaths compiled by USAFacts.org and commuter mobility data from the U.S. Census, adjusting the latter for reductions in mobility due to NPIs implemented beginning around March 15. The model revealed notable yet asynchronous reductions in disease transmission rates, reflected in changes to the estimated effective basic reproduction number (Re) in most counties during this time period. They then performed counterfactual simulations with the same model, moving the timing of NPI implementation either one week or two weeks sooner. In the first model, advancing NPIs by a week, to March 8, resulted in 601,667 fewer confirmed cases and 32,335 fewer deaths nationwide as of May 3. In the second model, implementing NPIs a full two weeks earlier, on March 1, resulted in 1,041,261 fewer confirmed cases and 59,351 fewer deaths. Pei et al. acknowledge that their modeling simplifies some assumptions related to general uncertainty, economic concerns, administrative decision-making, and public adherence to social distancing rules. However, they also point to continuing successes in countries such as South Korea, New Zealand, Vietnam, and Iceland that did implement NPIs in early March, suggesting that tens of thousands of cases and deaths in the U.S. "could have been averted, not merely postponed."

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Physical distancing polices not enough to protect lower-income people: BU study

BOSTON UNIVERSITY SCHOOL OF MEDICINE

Research News

 

A new Boston University School of Public Health study of the first four months of America's coronavirus epidemic, published in the journal Nature Human Behaviour, shows that physical distancing (also called "social distancing") policies had little effect on lower income people still needing to leave their homes to go to work--but does show them staying home when they could.

"If lower-income people were simply ignoring the trend towards physical distancing, we would have expected them to continue going to places like supermarkets, liquor stores, and parks at the same rates as before. Instead, their visits dropped at almost the same rates as the very highest-income group," says study lead author Dr. Jonathan Jay, assistant professor of community health sciences at BUSPH.

"This indicates that lower income people were just as aware and motivated as higher-income people to protect themselves from COVID-19, but simply couldn't stay home as much because they needed to go to work," he says.

Jay and colleagues used anonymized mobility data from smartphones in over 210,000 neighborhoods (census block groups) across the country, each neighborhood categorized by average income. They were able to see whether people from these neighborhoods stayed home, left home and appeared to be at work--staying at another location for at least three hours during typical working hours, or making multiple stops that looked like delivery work. The researchers also tracked movement to "points of interest": beer, wine and liquor stores; carryout restaurants; convenience stores; hospitals; parks and playgrounds; places of worship; and supermarkets.

"The difference in physical distancing between low- and high-income neighborhoods during the lockdown was just staggering," says study co-author Dr. Jacob Bor, assistant professor of global health and epidemiology at BUSPH.

"While people in high-income neighborhoods retreated to home offices, people in low-income neighborhoods had to continue to go to work--and their friends, family, and neighbors had to do the same," he says. "Living in a low-income neighborhood is likely a key risk factor for COVID-19 infection."

To analyze the role that policies played in these mobility patterns, the researcher used the COVID-19 U.S. State Policy Database (CUSP), a project led by study co-author Dr. Julia Raifman, assistant professor of health law, policy & management at BUSPH.

They found that the huge drop in mobility early in March had little to do with state policy, following similar patterns in different states regardless of when their orders went into effect. When state policies did go into effect, they modestly decreased mobility further--but did nothing to close the gap between low- and high-income neighborhoods.

"The orders did not have the effect of making it easier for lower-income people to stay home," Jay says. But they did stay home to the degree possible, visiting non-work non-home locations less--which counters a major narrative about how different groups of people have responded to COVID, Jay says. "Early in the pandemic, there was a lot of talk about 'non-compliance,' and it was rarely directed at the people with the most power and privilege," he says.

"We found strong evidence of compliance among the people who are most economically marginalized, which because of structural racism disproportionately includes people of color. As the pandemic has played out, the evidence of poor safety practices at the very highest levels of power has become more clear.

"Still, it's deeply troubling that throughout the pandemic, staying home has been a choice for some people and not for others."

The researchers say that closures are an important tool for states and cities to prevent the spread of the coronavirus, but that they need to be accompanied by other policies that make it easier for frontline workers to protect themselves.

"That people living in low-income households are more likely to face exposure to COVID-19 at work increases the importance of complementary policies, such as mask requirements in indoor spaces, that protect essential workers from COVID-19," Raifman says.

"One of the most important arguments for mask mandates is that they protect the folks who are in public spaces not because they want to be, but because showing up is how they make ends meet," Jay says. He also points to "policies that make it easier to work from home, stay home sick, and not to take a risky new job just to put food on the table."

However, Jay says, policies that make it easier to stay home only help if people have homes. As a wave of evictions and foreclosures sweeps the country, he says extending moratoriums and enacting other housing policies continue to be an important part of the picture.

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About the Boston University School of Public Health

Founded in 1976, the Boston University School of Public Health is one of the top five ranked private schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations--especially the disadvantaged, underserved, and vulnerable--locally and globally.

Coming out as bisexual associated with increased risk of smoking: BU study

BOSTON UNIVERSITY SCHOOL OF MEDICINE

Research News

 

For many years, lesbian, gay, bisexual, and other non-heterosexual (LGB+) folks have been known to be more likely to smoke than their straight counterparts.

But a new, first-of-its-kind Boston University School of Public Health (BUSPH) study paints a more precise picture by looking at LGB+ identities separately and over time, finding that bisexuality is the identity most associated with smoking, especially around the time of coming out.

Published in the journal JAMA Pediatrics, the nationally-representative cohort study followed 7,843 youth and young adults over three years, finding that those who came out as bisexual were twice as likely as consistently-heterosexual participants to start smoking. Coming out as lesbian, gay, or another non-heterosexual identity, or having a consistent LG+ identity, was not associated with being more likely to smoke.

The study "highlights the importance of moving beyond static measures of sexual identity towards more dynamic measures that capture critical periods of vulnerability," says Dr. Andrew Stokes, assistant professor of global health at BUSPH and the study's corresponding author.

"This approach turned out to be really important, because it revealed disparities that would have otherwise been missed if we measured identity at one time point, or grouped all LGB+ identities together," says study lead author Alyssa Harlow, a doctoral candidate at BUSPH.

"Bisexual young people may face unique forms of discrimination and stigma that increase their risk for smoking or other substance use behaviors," she says. "For example, they may experience stigma from heterosexual individuals as well as from within the LGB+ community. There's also prior research that shows that bisexual populations have worse mental health outcomes than LG+ populations.

'The findings point to a need for public health interventions specifically designed to address the unique needs, experiences, and stressors associated with coming out and identifying as bisexual," Harlow says.

For the study, the researchers used data from the first four waves of the nationwide Population Assessment of Tobacco and Health (PATH) study, which surveyed the same 14-29-year-olds three times between 2013 and 2018. (There were too few transgender respondents in this sample for the researchers to include gender identity in their analysis.) The researchers adjusted for other variables including sex, age, race/ethnicity, education level (for participants over 18) and parents' education level (for participants under 18), and where participants lived (urban/nonurban, and region of the U.S.).

By the third wave, 14% of the respondents had smoked at some point, and 6% were current smokers. The researchers found that the same sexual identity patterns held true both for having smoked at any point in the study period and for being a current smoker.

The researchers found that, compared to a consistent heterosexual identity, coming out as bisexual was associated with being more than twice as likely to smoke. Participants with LG+ identities in the first wave who shifted to a bisexual identity, or vice versa, were twice as likely to smoke.

On the other hand, participants with a consistent LG+ identity throughout the three waves of the study and participants who started out identifying as heterosexual and came out as LG+ were not more likely to smoke than those with a consistent heterosexual identity--while those with a consistent bisexual identity were slightly more likely to smoke.

The researchers say that the study's unique approach to LGB+ identities--separated and over time--could provide valuable insights for other issues that disproportionately affect the community, including mental health issues and substance use.

But to make that possible, more national surveys need to ask youth about their sexual orientation and gender identity, says study co-author Dielle Lundberg, a research fellow at BUSPH.

"The PATH study is unique because it asks youth about their sexual orientation and gender identity. Most national surveys do not," Lundberg says.

"We must advocate for better data. Whenever national surveys fail to ask about sexual orientation and gender identity, they are directly contributing to health inequities for LGBTQ+ populations."

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About the Boston University School of Public Health

Founded in 1976, the Boston University School of Public Health is one of the top five ranked private schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations--especially the disadvantaged, underserved, and vulnerable--locally and globally.

 

Study suggests most humans are vulnerable to type 2 diabetes

INDIANA UNIVERSITY SCHOOL OF MEDICINE

Research News

 

IMAGE: RESEARCHERS AT IU SCHOOL OF MEDICINE HAVE PUBLISHED A STUDY SUGGESTING MOST HUMANS ARE VULNERABLE TO TYPE 2 DIABETES. view more 

CREDIT: IU SCHOOL OF MEDICINE

Scientists have found that insulin has met an evolutionary cul-de-sac, limiting its ability to adapt to obesity and thereby rendering most people vulnerable to Type 2 diabetes.

A recent study from scientists at Indiana University School of Medicine, the University of Michigan and Case Western Reserve University has determined that the sequence of insulin has become entrenched at the edge of impaired production, an intrinsic vulnerability unmasked by rare mutations in the insulin gene causing diabetes in childhood. The study exploits biophysical concepts and methods to relate protein chemistry to the emerging field of evolutionary medicine.

Insulin is produced by a series of highly specific processes that occur in specialized cells, called beta cells. A key step is the folding of a biosynthetic precursor, called proinsulin, to achieve the hormone's functional three-dimensional structure. Past studies from this and other groups have suggested that impaired biosynthesis could be the result of diverse mutations that hinder the foldability of proinsulin.

This group sought to determine if the evolution of insulin in vertebrates--including humans--has encountered a roadblock. Has a complex series of steps imposed constraints that have frozen the sequence of insulin at a precipice of non-foldability? And if so, has this left humankind vulnerable to Type 2 diabetes as a pandemic disease of civilization?

According to the study published in the Proceedings of the National Academy of Sciences, the answers are yes and yes.

"Biological processes ordinarily evolve to be robust, and this protects us in the majority of cases from birth defects and diseases," said Michael Weiss, MD, PhD, Distinguished Professor at IU School of Medicine and lead investigator of the study. "Yet diabetes seems to be an exception."

Weiss and team looked at a subtle mutation in human insulin in relation to the insulins of other animals, such as cows and porcupines. The mutant human insulin functions within the range of natural variation among animal insulins, and yet this mutation has been excluded by evolution. The answer to this seeming paradox is that the forbidden mutation selectively blocks the folding of proinsulin and stresses beta cells.

The group discovered that even the slightest variation of the insulin-sequencing process not only impairs insulin folding (and eventual insulin secretion) but also induces cellular stress that leads to beta cell dysfunction and eventually permanent damage.

Weiss, who is also Chair of the Department of Biochemistry and Molecular Biology and a Precision Health Initiative Professor, said that the study highlights the importance of folding efficiency as a critical but hidden factor in the evolution of insulin over the past 540 million years. Humans have evolved to be vulnerable to diverse mutations in the insulin gene and that this vulnerability underlies a rare monogenic form of diabetes and provides an evolutionary backdrop to the present obesity-related diabetes pandemic.

National experts agree that this discovery provides key insight to better understanding the development of Type 2 diabetes in adults and children--which both are rising at alarming rates in Indiana and around the world.

"This study is a tour de force unraveling key elements of the structural biology of insulin that affect its synthesis and function," said Barbara Kahn, MD, George R. Minot Professor of Medicine at Harvard Medical School. "The authors highlight the fact that the insulin gene has been susceptible throughout evolution to mutations that impair insulin's function or stress beta cells. As we approach the 100th anniversary of the discovery of insulin, these elegant observations might lead to a better understanding of the pathogenesis of Type 2 diabetes."

Director of the University of Chicago Kolver Diabetes Center Louis Philipson, MD, agreed, adding that findings will shape future approaches to research in this area.

"The present findings define a major question for the future: whether harmful misfolding of proinsulin seen in patients bearing INS gene variants may also occur, at lower levels perhaps, but more broadly in the population of human Type 2 diabetes patients around the world," Philipson said.

Next, the group will work to fully define the sequence determinants that make proinsulin foldable in beta cells. Their hope is that this work will eventually lead to a new category of drugs that mitigate the cellular stress caused by proinsulin's precarious foldability and target cellular stress in beta cells, thereby preserving insulin-production for high-risk patients.

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This study was led by co-first authors Nischay Rege, MD, PhD, of Case Western Reserve University School of Medicine; Ming Liu, MD, PhD, of the University of Michigan Medical School; and Yanwu Yang, PhD, of IU School of Medicine. Additional authors are Balamurugan Dhayalan, PhD, and Yen-Shan Chen, PhD, at IU School of Medicine; Nalinda P. Wickramasinghe, PhD, Leili Rahimi, MD, Nelson Phillips, PhD, and Faramarz Ismail-Beigi, MD, PhD at Case Western Reserve University; and Huan Guo, MS, Leena Haataja, PhD, Jinhong Sun, MD, and Peter Arvan, MD, PhD, at the University of Michigan.

This work was supported by grants from the National Institutes of Health to Professors Weiss, Ismail-Beigi, Phillips and Arvan.

 

Astronomers discover clues that unveil the mystery of fast radio bursts

UNLV astrophysicist Bing Zhang contributes to understanding the physical mechanisms of fast radio bursts in three papers published in Nature

UNIVERSITY OF NEVADA, LAS VEGAS

Research News

 

IMAGE: THE FIVE-HUNDRED-METER APERTURE SPHERICAL RADIO TELESCOPE (FAST) IN GUIZHOU, CHINA. view more 

CREDIT: (PHOTO CREDIT: BOJUN WANG, JINCHEN JIANG & QISHENG CUI)

Fast radio bursts, or FRBs - powerful, millisecond-duration radio waves coming from deep space outside the Milky Way Galaxy - have been among the most mysterious astronomical phenomena ever observed. Since FRBs were first discovered in 2007, astronomers from around the world have used radio telescopes to trace the bursts and look for clues on where they come from and how they're produced. 

UNLV astrophysicist Bing Zhang and international collaborators recently observed some of these mysterious sources, which led to a series of breakthrough discoveries reported in the journal Nature that may finally shed light into the physical mechanism of FRBs.

The first paper, for which Zhang is a corresponding author and leading theorist, was published in the Oct. 28 issue of Nature. 

"There are two main questions regarding the origin of FRBs," said Zhang, whose team made the observation using the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China. "The first is what are the engines of FRBs and the second is what is the mechanism to produce FRBs. We found the answer to the second question in this paper."

Two competing theories have been proposed to interpret the mechanism of FRBs. One theory is that they're similar to gamma-ray bursts (GRBs), the most powerful explosions in the universe. The other theory likens them more to radio pulsars, which are spinning neutron stars that emit bright, coherent radio pulses. The GRB-like models predict a non-varying polarization angle within each burst whereas the pulsar-like models predict variations of the polarization angle.

The team used FAST to observe one repeating FRB source and discovered 11 bursts from it. Surprisingly, seven of the 11 bright bursts showed diverse polarization angle swings during each burst. The polarization angles not only varied in each burst, the variation patterns were also diverse among bursts. 

"Our observations essentially rules out the GRB-like models and offers support to the pulsar-like models," said K.-J. Lee from the Kavli Institute for Astronomy and Astrophysics, Peking University, and corresponding author of the paper.

Four other papers on FRBs were published in Nature on Nov. 4. These include multiple research articles published by the FAST team led by Zhang and collaborators from the National Astronomical Observatories of China and Peking University. Researchers affiliated with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey for Transient Astronomical Radio Emission 2 (STARE2) group also partnered on the publications.

"Much like the first paper advanced our understanding of the mechanism behind FRBs, these papers solved the challenge of their mysterious origin," explained Zhang. 

Magnetars are incredibly dense, city-sized neutron stars that possess the most powerful magnetic fields in the universe. Magnetars occasionally make short X-ray or soft gamma-ray bursts through dissipation of magnetic fields, so they have been long speculated as plausible sources to power FRBs during high-energy bursts. 

The first conclusive evidence of this came on April 28, 2020, when an extremely bright radio burst was detected from a magnetar sitting right in our backyard - at a distance of about 30,000 light years from Earth in the Milky Way Galaxy. As expected, the FRB was associated with a bright X-ray burst. 

"We now know that the most magnetized objects in the universe, the so-called magnetars, can produce at least some or possibly all FRBs in the universe," said Zhang. 

The event was detected by CHIME and STARE2, two telescope arrays with many small radio telescopes that are suitable for detecting bright events from a large area of the sky. 

Zhang's team has been using FAST to observe the magnetar source for some time. Unfortunately, when the FRB occurred, FAST was not looking at the source. Nonetheless, FAST made some intriguing "non-detection" discoveries and reported them in one of the Nov. 4 Nature articles. During the FAST observational campaign, there were another 29 X-ray bursts emitted from the magnetar. However, none of these bursts were accompanied by a radio burst. 

"Our non-detections and the detections by the CHIME and STARE2 teams delineate a complete picture of FRB-magnetar associations," Zhang said. 

To put it all into perspective, Zhang also worked with Nature to publish a single-author review of the various discoveries and their implications for the field of astronomy. 

"Thanks to recent observational breakthroughs, the FRB theories can finally be reviewed critically," said Zhang. "The mechanisms of producing FRBs are greatly narrowed down. Yet, many open questions remain. This will be an exciting field in the years to come."

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Read More

"No pulsed radio emission during a bursting phase of a Galactic magnetar," published in the Nov. 4 issue of Nature.

"The physical mechanisms of fast radio bursts," published in the Nov. 4 issue of Nature. 

"Diverse polarization angle swings from a repeating fast radio burst source," published in the Oct. 28 issue of Nature.