Daily Archives: 26 Feb 2021

Planetary Science

PSI’s Bill Hartmann Asks: Do Rings Around Lunar Impact Basins Need to be Perfect Circles & is That Important? (Planetary Science)

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These two images are from the paper “Effects of early intense bombardment on megaregolith evolution and on lunar (and planetary) surface samples” in Meteoritics and Planetary Science (November 2020) by PSI senior scientist emeritus, Bill Hartmann, and Alessandro Morbidelli, a well-known French/Italian dynamicist at the Observatoire de la Cote d’Azur, in Nice, France. The images show the best-preserved impact basin, “Orientale,” (discovered on the east “edge” of the moon by Hartmann and Kuiper in 1962). Morbidelli and co-workers in 2018 produced a new computer model of lunar cratering history, showing intense bombardment in the first few hundred million years after lunar formation about 4.5 million years ago, with declining impact rates since then (contrary to the now discarded “late heavy bombardment” theory that proposed negligible cratering in the first 500 million years after lunar formation). Hartmann and Morbidelli conclude that many giant impact basins, like Orientale, formed in the first few hundred million years, many of which have been since obliterated by later cratering.

On this radar-based topographic map of the lunar impact basin Orientale, blue and purple show the lower elevations and red shows the highest elevation. Credit: NASA

In past years, some lunar scientists proposed that the largest visible impact scar on the Moon may be the region known as ‘Oceanus Procellarum,’ a depressed, lava-covered region visible to the naked eye. It is partly obliterated by the more recent “Imbrium Impact Basin,” dated by many Apollo mission rock samples at age 3.9 billion years. However, the gravity-mapping team using the “GRAIL” orbiting instrument in 2011-12 argued against Procellarum being impact-related, because they found linear, not circular, structures surrounding Oceanus Procellarum below the Moon’s surface. These they interpreted “as part of the lunar magma plumbing system – the conduits that fed lava to the surface during ancient volcanic eruptions.” The Hartmann and Morbidelli illustration shows, however, that linear elements alone do not disprove an impact origin. The “rings” around Orientale and other basins contain linear elements, marked in white lines in the color image below. The illustration also shows that giant impacts created parts of the “lunar plumbing system.” The innermost white line (east side) can be seen in the black and white photo to have lava extrusions all along its base. In other words, as has been known for several decades, the linear segments in the “rings” of impact basins did “feed lava to the surface.”

Hartmann and Morbidelli agree that while Oceanus Procellarum is not yet proven to be an impact scar impacts of that size would deform the spherical shape of the moon, and the physical mechanics of the readjustment of the moon to spherical shape are not well understood.

Featured image: This photo of the lunar impact basin Orientale was taken by a lunar Orbiter. © NASA

Provided by PSI

Astronomy

Magnetic Fields Drive Astrophysical Jet Shapes (Astronomy)

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Outflows of matter are general features stemming from systems powered by compact objects such as black holes, active galactic nuclei, pulsar wind nebulae, accreting objects such as Young Stellar Objects (YSO) and mature stars such as our sun.

But the shape of those outflows, or astrophysical jets, vary depending on the magnetic field around them.

In new experiments, a Lawrence Livermore National Laboratory (LLNL) scientist and international collaborators found that outflow/magnetic field misalignment is a plausible key process regulating jet formation. The research appears in Nature Communications.

Using a high-powered laser at the École Polytechnique, the team created fast material outflows in a strong applied magnetic field as a surrogate for potential astrophysics conditions. The team specifically looked at the impact on jet formation of a misalignment between where the jet first forms and then the magnetic field.

Electron density maps of 3D plasma outflow simulations with a slightly (10 degrees) and highly (45 degrees) misaligned magnetic field. This work showed that jet formation is possible with a slightly misaligned field, but not with a large misalignment. © LLNL

For small misalignments, a magnetic nozzle forms and redirects the outflow in a parallel jet. For larger misalignments, this nozzle becomes increasingly asymmetric, disrupting jet formation.

“We found that outflow/magnetic field misalignment is a plausible key process regulating jet collimation in a variety of objects from our sun’s outflows to extragalatic jets,” said LLNL plasma physicist Drew Higginson, a co-author of the paper. “They also could provide a possible interpretation for the observed structuring of astrophysical jets.”

Astrophysical jets have varied morphologies from very high aspect ratio, collimated jets, to short ones that are either clearly fragmented or are just observed and are not able to sustain a high density over a long range.

But the mechanisms underlying these varied morphologies have been unclear. In light of observations made onto a variety of astrophysical objects, the team devised a possible scenario where the relative orientation between the outflow and the large-scale ambient magnetic field surrounding the object can play a major role orienting the dynamics of the outflow from a collimated one to a stunted, fragmented one.

Collaborators include University of Chicago; Institute of Applied Physics RAS, Nizhny Novgorod, Russia; Sorbonne Université, École Polytechnique; Institut Polytechnique de Paris, Palaiseau, France; Université de Bordeaux-CNRS-CEA, Talence, France; Universitá di Palermo, Palermo, Italy; Heinrich Heine Universität Düsseldorf, Düsseldorf, Germany; Universiá di Torino, Torino, Italy; INAF-Osservatorio Astronomico di Palermo, Palermo, Italy; and Joint Institute for High Temperatures RAS, Moscow, Russia.

The Department of Energy supported the LLNL portion of the work.

Featured image: This image taken with the Hubble Space Telescope shows how a bright, clumpy jet ejected from a young star has changed over time. Image courtesy of NASA.

Reference: Revet, G., Khiar, B., Filippov, E. et al. Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field. Nat Commun 12, 762 (2021). https://www.nature.com/articles/s41467-021-20917-x https://doi.org/10.1038/s41467-021-20917-x

Provided by LLNL

PHYSICS

Study Reveals Cause of 3D Asymmetry in ICF Implosions (Physics)

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Inertial confinement fusion (ICF) implosions require very high levels of symmetry in order to reach the high densities and temperatures required for fusion induced self-heating. Even percent-level deviations from perfect spherical symmetry can lead to significant distortions of the implosion and ultimately degrade fusion performance.

To that end, researchers from Lawrence Livermore National Laboratory (LLNL) conducted work to gain a better understanding about why this happens. The work was published in Physical Review Lettersand was featured as an Editor’s Suggestion.

Daniel Casey, LLNL physicist and lead author of the paper, said the work summarizes observations of areal-density asymmetries seeded by high-density carbon (HDC) capsule thickness asymmetries, helping to illuminate one of the principal causes of a significant degradation in ICF implosions at the National Ignition Facility (NIF), the world’s most energetic laser.

“These asymmetries can decrease the energy available to heat the hotspot and reduce the confinement of that energy,” Casey said. “It is like squeezing a balloon a little harder on one side than the other, at some point the balloon will attempt to vent out the weak spots.”  

The paper reveals that tiny imperfections in the capsule can grow into huge distortions of the implosion at peak compression. In fact, some recent experiments described in the paper show that sub-percent level non-uniformity (approximately 0.7 percent) in HDC capsule thickness can grow into approximately 25 percent variations in the fuel areal density and produce hotspot velocities on the order of 100 kilometers per second.

“This result is significant because if we know the causes for these asymmetries in ICF implosions, we are better able to predict them and understand their impact,” Casey said. “Perhaps most important, if we know the causes we can work on fixing them.”

The work was conducted by radiographing the pre-shot capsules before the experiment to determine the level of non-uniformity. Then after the experiment is performed, the team looked for signs of asymmetry in the observed residual hotspot velocity and shell areal-density asymmetry.

“This work was enabled in part by advances in diagnosing implosion asymmetry through observations of the hotspot velocity using neutron spectrometry,” Casey said. “Along with advances in measuring shell non-uniformity through neutron activation anisotropies.

“It is like the analogy of the balloon that is being squeezed harder on one side, if we find the hotspot velocity is very high in some direction and aligned with significant non-uniformity of the shell, we know that some aspects of the implosion were not adequately symmetric,” Casey explained. “Then the question becomes ‘why that direction?’ ”

The team then looked at comparing the pre-shot radiographs of the capsule to the hotspot velocity. They found that capsule thickness variations deduced from the radiographs are often correlated in both direction and magnitude. This strongly suggests that the shell non-uniformities are at least one of the principal causes of asymmetry as diagnosed through the hotspot velocity.

Casey said that understanding and improving the performance of ICF implosions is an important part of the Lab’s research on the NIF.

“Now that we have found HDC shell non-uniformity to be an important degradation of implosion performance, we are working to increase the accuracy of our metrology of the shells and also to improve the manufacture of HDC to produce more uniform shells,” he said.

Co-authors of the paper include Brian MacGowan, Jim Sater, Alex Zylstra, Otto Landen, Jose Milovich, Omar Hurricane, Annie Kritcher, Matthias Hohenberger, Kevin Baker, Sebastien Le Pape, Tilo Döppner, Chris Weber, Juergen Biener, Chris Young, Steve Haan, Ryan Nora, Steven Ross, Harry Robey, Michael Stadermann, Abbas Nikroo, Debbie Callahan, Richard Bionta, Kelly Hahn, Alastair Moore, Dave Schlossberg and Matt Bruhn from LLNL; Haibo Huang, Casey Kong, Kevin Sequoia, Neal Rice and Michael Farrell from General Atomics in San Diego; and Christoph Wild from Diamond Materials in Germany.

Featured image: This is a HYDRA simulation of an ICF implosion with an imposed HDC shell thickness asymmetry. The result plotted here is a significantly distorted shell at peak compression (background color scale) along with the induced hotspot flow field. Image by Chris Schroeder and Jose Milovich/LLNL.

Reference: D. T. Casey et al., “Evidence of Three-Dimensional Asymmetries Seeded by High-Density Carbon-Ablator Nonuniformity in Experiments at the National Ignition Facility”, Phys. Rev. Lett. 126, 025002 – Published 12 January 2021. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.025002

Provided by LLNL

Chemistry

Using Neutron Scattering to Better Understand Milk Composition (Chemistry)

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By using a more complex model for neutron scattering data, researchers can better understand the composition of materials such as milk.

Neutron scattering is a technique commonly used in physics and biology to understand the composition of complex multicomponent mixtures and is increasingly being used to study applied materials such as food. A new paper published in EPJ E by Gregory N Smith, Niels Bohr Institute, University of Copenhagen, Denmark, shows an example of neutron scattering in the area of food science. Smith uses neutron scattering to better investigate casein micelles in milk, with the aim of developing an approach for future research.

Smith, also a researcher at the ISIS Neutron and Muon Source in the UK, explains why better modelling of how neutrons are scattered by structures in colloid materials is important. “How well you can understand the structure of a system from scattering data depends on how good your model is, and the better and more realistic your model, the better your understanding,” the researcher says. “This is true for food as for any material. A better understanding of the structure of casein in milk can help better understand dairy products.”

Neutron scattering can be used to investigate fluids by swapping the water solvent within them with heavy water –  water where hydrogen is replaced with deuterium, an isotope of hydrogen possessing a nucleus with a proton and a neutron rather than just a proton.

“I set out to see if the model that I had developed for casein micelles in milk could also be applied to existing neutron scattering data. The particular set of data that I looked at was extensive and had measurements from a large number of backgrounds, with different water to heavy water ratios,” Smith continues. “This meant that I would not only be able to see if the model worked with different measurements, which would support its wider application, but also meant that I would be able to better quantify the composition of milk.”

Smith further explains that he was pleased to see his model agreed well when compared with existing data, something that is not always guaranteed when testing out new models with scattering experiments. What surprised the researcher, however, was just how much scattering occurred even in skimmed milk with less fat droplets.

“Even common and everyday materials, such as food, have a complex structure on the nanoscale,” Smith concludes. “You might look at milk and just see a cloudy liquid, but inside there are proteins that self-assemble into colloids, proteins that are free in solution, large droplets of fat, and many other components as well.

“By using a technique like scattering to study such a system, you can get beneficial information about all these constituents.”

References: G.N. Smith (2021) An Alternative Analysis of Contrast-variation Neutron Scattering Data of Casein Micelles in Semi-deuterated Milk, Eur. Phys. J. E 44:5. https://doi.org/ 10.1140/epje/s10189-021-00023-y

Provided by Link Springer

Physiology

Exercise May Help Slow Memory Loss For People Living with Alzheimer’s Dementia (Physiology)

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Promising new research shows aerobic exercise may help slow memory loss for older adults living with Alzheimer’s dementia.

ASU Edson College of Nursing and Health Innovation Professor Fang Yu led a pilot randomized control trial that included 96 older adults living with mild to moderate Alzheimer’s dementia.

Participants were randomized to either a cycling (stationary bike) or stretching intervention for six months. Using the Alzheimer’s Disease Assessment Scale-Cognition (ADAS-Cog) to assess cognition, the results of the trial were substantial.

The six-month change in ADAS-Cog was 1.0±4.6 (cycling) and 0.1±4.1 (stretching), which were both significantly less than the expected 3.2±6.3-point increase observed naturally with disease progression.

Dr. Fang Yu © Arizona State University

“Our primary finding indicates that a six-month aerobic exercise intervention significantly reduced cognitive decline in comparison to the natural course of changes for Alzheimer’s dementia. However, we didn’t find a superior effect of aerobic exercise to stretching, which is likely due to the pilot nature of our trial. We don’t have the statistical power to detect between-group differences, there was substantial social interaction effect in the stretching group, and many stretching participants did aerobic exercise on their own.” Yu said.

The findings are described in a recently published article, Cognitive Effects of Aerobic Exercise in Alzheimer’s Disease: A Pilot Randomized Controlled Trial, in the Journal of Alzheimer’s Disease.

Yu says their results are encouraging and support the clinical relevance of promoting aerobic exercise in individuals with Alzheimer’s dementia to maintain cognition.

“Aerobic exercise has a low profile of adverse events in older adults with Alzheimer’s dementia as demonstrated by our trial,” said Yu. “Regardless of its effect on cognition, the current collective evidence on its benefits supports the use of aerobic exercise as an additional therapy for Alzheimer’s disease.”

Featured image: Promising new research shows aerobic exercise may help slow memory loss for older adults living with Alzheimer’s dementia. © Arizona State University

Reference: Yu, Fang et al. ‘Cognitive Effects of Aerobic Exercise in Alzheimer’s Disease: A Pilot Randomized Controlled Trial’. 1 Jan. 2021 : 1 – 12. https://content.iospress.com/articles/journal-of-alzheimers-disease/jad201100

Provided by IOS Press

PHYSICS

Investigating Dense Plasmas With Positron Waves (Physics)

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Astrophysical and lab-created plasmas under the influence of magnetic fields are the source of intense study. New research seeks to understand the dynamics of position waves travelling through these clouds of highly ionised gas.

The investigation of Electron-Positron-Ion (EPI) plasma — a fully ionised gas of electrons and positrons that includes astrophysical plasmas like solar winds — has attracted a great deal of attention over the last twenty years. A new study published in EPJ D by Garston Tiofack, Faculty of Sciences, University of Marousa, Cameroon, and colleagues, assesses the dynamics of positron acoustic waves (PAWS) in EPI plasmas whilst under the influence of magnetic fields, or magnetoplasmas.

The authors studied the changes in PAWs using a framework of Korteweg-de Vries (KdV) and modified Korteweg-de Vries (mKdV) equations finding a former led to compressive positron acoustic solitary waves (PASWs), whilst the latter resulted in the same and additional rarefactive PASWs. Mathematical models and numerical simulations performed by the researchers also allowed them to consider the effect of various other factors on the magnetoplasma including the concentration of hot electrons to that of positrons and applied nonthermal parameters.

The team discovered that the transition to chaos in the magnetoplasma depends strongly on the frequency and strength of external periodic perturbations.

The study thus serves a useful guide to understanding the changes that occur at magnetoplasma in Auroral Acceleration Regions (AAR) and as they apply to PAWs. The team’s results could also help develop research into astrophysical plasma, which include solar flares and interstellar plasmas thus giving physicists a window into the processes that take place in extreme environments like active galactic nuclei and supernovae explosions.

Bringing the team’s research down to earth somewhat, it could also assist teams which generate plasma across the globe. These plasmas play a major role in a new generation of nuclear fusion reactors, which aim to generate clean power by replicating the processes that occur in the stars.

These plants use plasmas which are controlled with the use of powerful magnetic fields, thus making the understanding of such influences of critical importance to future clean energy production.

References: B.B. Mouhammadoul, C. G. L. Tiofack, A. Alim, A. Mohamadous (2021) Positron-acoustic travelling waves solutions and quasi-periodic route to chaos in magnetoplasmas featuring Cairns nonthermal distribution, European Physical Journal D 75:61, https://doi.org/10.1140/epjd/s10053-020-00010-6

Provided by Link Springer

Medicine

Discovery: Neanderthal-derived Protein May Reduce the Severity of COVID-19 (Medicine)

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Researchers at the Lady Davis Institute (LDI) at the Jewish General Hospital have discovered that increased levels of the protein OAS1 are associated with reduced mortality and less severe disease requiring ventilation among patients with COVID-19. Using drugs that boost OAS1 levels could be explored to try to improve these outcomes. The findings are published today in Nature Medicine.

“Our analysis shows evidence that OAS1 has a protective effect against COVID-19 susceptibility and severity,” explains Dr. Brent Richards, a senior investigator at the LDI’s Centre for Clinical Epidemiology and Professor of Medicine, Human Genetics, Epidemiology and Biostatistics at McGill University. “This is a very exciting development in the race to identify potential therapies to treat patients because there are already therapies in pre-clinical development that boost OAS1 and could be explored for their effect against SARS-CoV-2 infection.”

Understandably, a great deal of effort is being invested in vaccine development. However, with hundreds of millions of people already infected around the world, it is important not to neglect the search for disease-specific therapies since few such therapies have been identified. Moreover, given the prevalence of vaccine hesitancy in the community and uncertainty as to how long any vaccine will prove to be protective, COVID-19 is most probably going to be a global issue for years to come. Thus, the need for therapeutic treatments will continue.

Researchers in Dr. Richards’ lab explored proteins detectable in peripheral blood as a potential target. The challenge lay in determining which proteins play a causal role in disease progression, since their levels may also be influenced by COVID-19 itself or other confounding factors. Recent advances in proteomic technology – that is, the capacity to isolate and measure hundreds of circulating proteins at once – combined with genetic analyses through Mendelian randomization (MR) makes possible the delicate work of untangling which proteins affected COVID-19 adverse outcomes, rather than vice versa.

From genetic determinants of 931 circulating proteins, Dr. Sirui Zhou, a post-doctoral fellow at the LDI and first author on the paper, found that increase in OAS1 levels was associated with reduced COVID-19 death or ventilation, hospitalization, and susceptibility in up to 14,134 COVID-19 cases and 1.2 million controls. The results were consistent in multiple sensitivity analyses. They proceeded to measure OAS1 levels in 504 patients with different COVID-19 outcomes from the Biobanque Québec COVID-19, and found that increased OAS1 levels in post-infection patients were associated with protection against very severe COVID-19, hospitalization, and susceptibility.

“The protective effect was particularly large,” points out Dr. Zhou, “such that we observed a 50% decrease in the odds of very severe COVID-19 per standard deviation increase in OAS1 circulating levels. Interestingly, for non-African peoples, this protective effect is likely inherited from a Neanderthal derived form of OAS1 called p46.”

This form of OAS1 likely emerged in people of European ancestry through interbreeding with Neanderthals tens of thousands of years ago. Evolutionary pressure slowly increased the prevalence of this form of OAS1, such that it is now detectable in more than thirty-percent of people of European descent. It is likely that the form of the protein has served as protection against earlier pandemics.

Because drug development, even in the accelerated environment of pandemic research, takes time it is particularly exciting that molecules which can increase OAS1 activity are currently in pre-clinical development for eventual deployment in clinical trials.

“Our recommendation is that those medications that trigger increased OAS1 levels be further studied for their effect on COVID-19 outcomes so that we may better treat infected patients,” said Dr. Richards.

Featured image: Association of OAS1 levels with COVID-19 outcomes from the case–control study in BQC19. © Zhou et al.

Reference: A Neanderthal OAS1 isoform protects individuals of European ancestry against COVID-19 susceptibility and severity, Sirui Zhou et al, Nature Medicine, doi: https://doi.org/10.1038/s41591-021-01281-1

Provided by McGill University

Medicine

A Weak Heart Makes A Suffering Brain (Medicine)

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Evidence of Disturbed Gene Activity in the Brain as a Result of Heart Problems

Heart problems cause disturbed gene activity in the brain’s memory center, from which cognitive deficits arise. Researchers at the German Center for Neurodegenerative Diseases (DZNE), the University Medical Center Göttingen (UMG) and the German Center for Cardiovascular Research (DZHK) come to this conclusion based on laboratory studies. They consider that they have found a possible cause for the increased risk of dementia in people with heart problems. In mice, a specific drug which is known to affect gene activity alleviated the mental deficits. The involved experts see these results as potential approaches for therapies. The study data are published in the scientific journal “EMBO Molecular Medicine”.

In Germany, about four million people are affected by what is called “heart failure”: Their heart muscle is too weak to pump enough blood through the body and is therefore abnormally enlarged. Physical fitness and quality of life suffer as a result. Moreover, affected individuals have an increased risk of developing dementia. “People with cardiological problems and heart failure in particular may experience noticeable cognitive deficits and increased risk of developing Alzheimer’s disease. Possible reasons include impaired blood supply to the brain and dysfunction of the hippocampus, which is the memory’s control center,” explained André Fischer, research group leader at the DZNE’s Göttingen site and professor at the Department of Psychiatry and Psychotherapy at UMG. “Yet, there is a lack of therapies to effectively treat cognitive deficits in people with heart problems. This is because it is completely unclear which deficiencies are triggered in neurons. There was no data on this so far.”

Stressed Cells

Now, a team led by Prof. André Fischer and Prof. Karl Toischer (Clinic of Cardiology and Pneumology at UMG and DZHK’s Göttingen site) is presenting findings on this subject for the first time. The researchers observed in mice that impaired gene activity developed in the hippocampus as a result of heart problems. “In memory tests, mice with heart failure performed significantly worse than their healthy mates,” Fischer explained. “We then examined the neurons of the hippocampus. In the mice with heart failure, we found increased cellular stress pathways and altered gene activity in neurons.”

Tight Windings

The genome of a mouse – and also of humans – comprises around 20,000 genes. In any given cell, however, only a part of them is active, switched on, so to speak. This is not a mere on or off state: the activity can be strong or less strong. This depends, among other things, on how tightly the DNA (the thread-like molecule that carries the genome) is wound and how accessible the genes on it are. In both mice and humans, the DNA is more than a meter long. But in a cell, the molecule is so tightly packed that it fits into the nucleus. “Genes can only be active if they are accessible to the cell’s machinery. To this end, the DNA needs to be wound a little more loosely at the relevant sites. This is similar to a ball of yarn with loops sticking out of it,” said Fischer. In the current study, the DNA was found to be more tightly wound in neurons of mice with heart problems than in healthy mates. Various genes important for hippocampal function were therefore less active than in healthy mice.

A Drug Improved Memory

The scientists identified chemical changes in the histones as the cause of the tight winding. Histones are special proteins: The DNA wraps around them, much like yarn around a spool of thread. Fischer’s research group has been studying histones and other players that influence gene activity for quite some time – in technical jargon they are called “epigenetic mechanisms”. In this context, the researchers are also investigating drugs. In previous studies, they were able to show that the cancer drug “vorinostat” can alleviate genetically driven as well as age-related memory problems in mice. Currently, vorinostat is being investigated for the therapy of people with Alzheimer’s in a clinical trial of the DZNE. In the current study, the scientists treated mice with heart failure with this drug. They found that the heart’s pumping capacity did not change significantly, but memory performance improved.

Interdisciplinary Cooperation

“Vorinostat has been shown to act on histones and thus on gene activity. Our study thereby provides initial clues about the molecular processes that contribute to cognitive dysfunction following heart problems, and it indicates potential approaches for therapy,” Fischer commented on the results. “Fact is, however, that we do not yet understand why, as a result of heart failure, gene activity in the hippocampus is disturbed. What is the role of the deficient blood supply to the brain? Does the troubled heart release substances that affect the histones? We intend to investigate this in patients with heart problems. As with our current study, which involved experts from neuroscience and cardiac research, we aim to address these questions in an interdisciplinary way.”

On the German Center for Neurodegenerative Diseases (DZNE)

The DZNE investigates all aspects of neurodegenerative diseases (such as Alzheimer’s and Parkinson’s and Amyotrophic lateral sclerosis) in order to develop novel approaches of prevention, treatment, and health care. The DZNE is comprised of ten sites across Germany and cooperates closely with universities, university hospitals, and other institutions on a national and international level. The DZNE is a member of the Helmholtz Association.

Featured image: Decorative image shows a network like connection between the brain and the heart © Inna-stock.adobe.com

Reference: Epigenetic gene-expression links heart failure to memory impairment.
Rezaul Islam et al.
EMBO Molecular Medicine (2021)
DOI: 10.15252/emmm.201911900

Provided by DZNE

Biology

Genes Identified That Increase The Risk of Obesity But Also Protect Against Disease (Biology)

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An international team of scientists, including researchers at the University of Copenhagen, have identified 62 genes that lead to both higher levels of body fat but a lower risk of cardiovascular and metabolic diseases. These genes may help to keep body fat healthy, and open a new avenue for developing drugs that lower the risk of diabetes and heart disease.

People living with obesity tend to have unhealthy glucose and lipid levels in their blood, as well as high blood pressure. As a result, they are more at risk of cardiovascular and metabolic diseases. But scientists have observed that up to 45% of people living with obesity have healthy blood pressure and glucose and lipid levels, and therefore may not be at high risk of disease. It is poorly understood why this group of people with obesity remain healthy.

Now a team of researchers – led by scientists at the University of Copenhagen and Icahn School of Medicine at Mount Sinai, New York – have identified a range of genes that are linked to both elevated levels of body fat, as well as offering protection from some of the negative health impacts of obesity. The results were published in the journal Nature Metabolism.

Associate Professor Tuomas Kilpeläinen from the Novo Nordisk Foundation Center for Basic Metabolic Research (CBMR) at the University of Copenhagen says the findings shed new light on the biology that may disconnect higher levels of body fat from a higher risk of diabetes and heart disease.

“The identified genes seem to benefit our health by helping to maintain healthy fat tissue. Some of the genes may offer targets for the development of new therapies that lower the risk of diabetes and heart disease by improving the health of our fat tissue,” says Tuomas Kilpeläinen.

Identified new genes associated with fat tissue health

The scientists made the discovery by analyzing data from hundreds of thousands of people who had been assessed for their body fat and disease risk markers. They identified 62 sections of the genome that were significantly associated with both high levels of body fat and lower risk of cardiometabolic diseases. Further analyses showed that the genes had a range of functions in the body, including the regulation and development of fat cells, distribution of body fat, as well as energy regulation and inflammation.

Staff Scientist Lam Opal Huang from CBMR carried out the computational analyses that identified the genes.

“We used a data-driven approach in this study, which led us to find new genes associated with fat tissue health, instead of the known obesity genes associated with the central nervous system, which control satiety and are typically linked to unhealthy obesity,” says Lam Opal Huang.

According to Professor Ruth Loos from the Icahn School of Medicine at Mount Sinai, this new knowledge is a step toward a more nuanced approach to treating obesity.

“Clearly, obesity is a complex disease, and not every individual with excess body weight is equally at risk of developing cardiometabolic diseases. Knowing which genes protect people from developing diabetes and cardiovascular disease will eventually help us better diagnose and treat individuals with obesity.”

Read more: Genome-wide discovery of genetic loci that uncouple excess adiposity from its comorbidities

Provided by University of Copenhagen