Hubble Captures Fading of the Stingray Nebula (Astronomy)

Even though the Universe is constantly changing, most processes are too slow to be observed within a human lifespan. However, the Stingray Nebula is now offering scientists a special opportunity to observe a system’s evolution in real time.

Archival data from the NASA/ESA Hubble Space Telescope reveal that the nebula Hen 3-1357, nicknamed the Stingray nebula, has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceedingly rare, say researchers. These images captured by Hubble in 1996 (left), when compared to Hubble images taken in 2016 (right), show a nebula that has drastically dimmed in brightness and changed shape. Bright blue shells of gas near the centre of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the distant Universe. ©NASA, ESA, B. Balick (University of Washington), M. Guerrero (Instituto de Astrofísica de Andalucía), and G. Ramos-Larios (Universidad de Guadalajara)

Images captured by Hubble in 2016, when compared to Hubble images taken in 1996, show a nebula that has drastically dimmed in brightness and changed shape. Bright blue shells of gas near the centre of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the distant Universe.

Researchers discovered unprecedented changes in the light emitted by glowing gas — nitrogen, hydrogen and oxygen — that is being blasted off by the dying star at the centre of the nebula. The oxygen emission, in particular, dropped in brightness by a factor of nearly 1000.

“In most studies, the nebula usually gets bigger,” said Bruce Balick of the University of Washington, USA, who led the new research. “Here, it’s fundamentally changing its shape and getting fainter, and doing so on an unprecedented timescale.”

Pictured here is the region surrounding the Stingray Nebula. Archival data from the NASA/ESA Hubble Space Telescope has revealed that the nebula has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceedingly rare, say researchers. ©ESA/Hubble, Digitized Sky Survey 2. Acknowledgement: Davide De Martin

“Because of Hubble’s optical stability, we are very, very confident that this nebula is changing in brightness,” said team member Martin Guerrero of the Instituto de Astrofísica de Andalucía in Granada, Spain. “That easy to see since, unlike the nebula, all of the other stars in the Hubble image – including a distant companion star – stayed constant in brightness.”

The researchers note that while speculating on causes for this surprising finding, it’s important to explore the properties of the dying star at the centre of the Stingray nebula, which influences the structure and brightness of the nebula.

A 2016 study by Nicole Reindl of the University of Leicester, UK, and a team of international researchers, also using Hubble data, noted that the star at the centre of the Stingray nebula, SAO 244567, is special in its own right.

Observations from 1971 to 2002 showed the temperature of the star skyrocketing to almost ten times hotter than the surface of our Sun. Reindl speculates the temperature jump was caused by a brief flash of helium fusion that occurred outside the core of the central star. After that the star began to cool again, returning to its previous stage of stellar evolution.

The team studying the rapid fading of the Stingray nebula can only speculate at this time what’s in store for the future of this young nebula.

Video 1: This video morphs archival data from the NASA/ESA Hubble Space Telescope to reveal that the nebula Hen 3-1357, nicknamed the Stingray nebula, has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceedingly rare, say researchers. These images captured by Hubble in 1996, when compared to Hubble images taken in 2016, show a nebula that has drastically dimmed in brightness and changed shape. Bright blue shells of gas near the centre of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the distant Universe. Credit: NASA, ESA, B. Balick (University of Washington), M. Guerrero (Instituto de Astrofísica de Andalucía), and G. Ramos-Larios (Universidad de Guadalajara), M. Kornmesser (ESA/Hubble)

Video 2: This video zooms into the nebula Hen 3-1357, nicknamed the Stingray nebula, which has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceedingly rare, say researchers. Credit: ESA/Hubble, Digitized Sky Survey, Nick Risinger (skysurvey.org) Music: Astral Electronic

References: Bruce Balick, Martín A. Guerrero, Gerardo Ramos-Larios, “The Fall of the Youngest Planetary Nebula, Hen 3-1357”, ArXiv, pp. 1-5, 2020. https://arxiv.org/abs/2009.01701v1

Provided by ESA/Hubble

120,000-year-old Supernova Remnants Detected in Neighboring Galaxy (Astronomy)

Western Sydney University researchers have discovered the ‘senior citizens’ of our neighbouring galaxy – close to 120,000-year-old remains of exploding stars known as supernova remnants.

©Western Sydney University

Published in the prestigious ‘Monthly Notices of the Royal Astronomical Society’, the research analysed data from 19 celestial objects located in outlying regions of our neighbouring galaxy, the Large Magellanic Cloud. They uncovered 16 new supernova remnants that were significantly older and only visible by optical telescope.

Lead author PhD candidate Miranda Yew from the School of Science explained the new class of supernova remnants were once young and bright stars.

“Their contemporaries from the central, dense part of the galaxy vanished a long time ago, as they merged into the vast interstellar medium. However, these stubborn celestial objects managed to survive — this is because the conditions in the galaxy’s outskirts are far more favourable for a longer life,” said Ms Yew.

Using observations from the latest generation of optical telescopes based in Chile, the research team found also that the new Large Magellanic Cloud supernova remnants candidates were larger by a factor of two compared to other previously confirmed supernova remnants.

“Our analysis suggests we discovered a previously unknown class of large and predominantly optically visible supernova remnants,” explained Ms Yew.

“We believe these objects are mainly residing in a very rarefied environment and are up to 120,000 years old.”

“The rarefied environment allows the supernova remnants to expand with nothing to impede them. Due to their age, radio emission particles can no longer be detected by even most sensitive instruments.”

According to the research team, which included supervisors Professor Miroslav Filipovic, from the University’s School of Science and Chair of Western Sydney University Penrith Observatory and Dr Evan Crawford, from the School of Computer, Data and Mathematical Sciences, the findings suggest the Large Magellanic Cloud — which is significantly smaller than the Milky Way — is going through a period of recent star formation.

The data analysed in the paper is from the Magellanic Cloud Emission Line Survey. The research team plan to further explore the supernova remnants in X-rays with eROSITA — a joint project with the Max Planck Institute for Extraterrestrial Physics in Farching, Germany.

For more information, download New Optically Identified Supernova Remnants in the Large Magellanic Cloud (opens in new window).

References: Yew, Miranda; Filipović, Miroslav D.; Stupar, Milorad; Points, Sean D.; Sasaki, Manami; Maggi, Pierre; Haberl, Frank; Kavanagh, Patrick J.; Parker, Quentin A.; Crawford, Evan J.; Vukotić, Branislav; Urošević, Dejan; Sano, Hidetoshi; Seitenzahl, Ivo R.; Rowell, Gavin; Leahy, Denis; Bozzetto, Luke M.; Maitra, Chandreyee; Leverenz, Howard; Payne, Jeffrey L. Et al., “New optically identified supernova remnants in the Large Magellanic Cloud”, Monthly Notices of the Royal Astronomical Society, Volume 500, Issue 2, pp.2336-2358, 2020. DOI:
10.1093/mnras/staa3382

Provided by Western Sydney University

A Three-dimensional View of The Milky Way (Astronomy / Cosmology)

The Apex telescope makes it possible to observe molecular clouds and star births in the galactic plane.

In our Milky Way, there are about 200 billion suns as well as large quantities of gas, some of which serves as raw material for star births. The gas collects in compact lumps but also appears as extended molecular clouds. Astronomers have used the Apex sub-millimetre telescope in Chile to look deep into the galactic plane and measure the interstellar medium. They studied the distribution of the cold molecular gas in the inner region of the Milky Way with unprecedented accuracy. The researchers catalogued more than 10,000 interstellar clouds. They found out that currently only about 10% of them contain stars. The project is called SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium) and covers an area of 84 square degrees in the southern sky.

Colourful variety: The section shows interstellar clouds in a small area of about 5% of the total SEDIGISM mapping; each of these clouds is coloured differently. The small picture in the upper left diagrams the course of the spiral arms in the Milky Way. The grey region marks the complete area of the SEDIGISM mapping. In this illustration, the direction of the sector is light blue. © Ana Duarte-Cabral, Alex Pettitt, and James Urquhart

The mapping contains data from 2013 to 2017, which was collected by the 12-metre Apex telescope in the Chilean Andes. “With the publication of this most detailed map of cold molecular clouds in the Milky Way to date, a long-term observation project is now coming to fruition”, says Frederic Schuller from the Max Planck Institute for Radio Astronomy, the project leader of SEDIGISM.

Scientists have been able to observe the southern part of the inner Milky Way with an angular resolution of 30 arcseconds; this corresponds to ¹⁄₆₀ of the apparent diameter of the full moon in the Earth’s sky. They have also gained valuable information on structure, distance, and velocity for all galactic molecular clouds in about two thirds of the inner disc of the Milky Way.

The researchers observed the spectral lines of the carbon monoxide molecule – including the rare isotopes 13CO and C18O – and deduced the mass and three-dimensional distribution of cold and dense molecular gas in the interstellar medium. Various structures such as filaments and recesses were found; these are the result of different physical effects.

Molecular clouds contain the raw material from which new stars are formed. The mapping of these clouds is therefore necessary to determine important parameters such as the efficiency of star formation in the Milky Way. Structures and physical conditions within the clouds provide the fundamental basis for the theories of star formation. It is therefore important to spatially resolve the individual clouds and distinguish them from each other.

One key to the success was the 12-metre Apex telescope with its highly accurate surface and one of the world’s best locations for sub-millimetre astronomy. The instrument is located at an altitude of 5100 meters on the Chajnantor Plain in the Chilean Atacama Desert. Here, there is extremely low water vapour content and thus excellent transparency of the atmosphere.

Video: Journey through the Milky Way: Atronomers have used the Apex sub-millimetre telescope in Chile to look deep into the galactic plane and measure the interstellar medium. They studied the distribution of the cold molecular gas in the inner region of the Milky Way with unprecedented accuracy, cataloguing more than 10,000 interstellar clouds.

The new data complement a series of mappings of the galactic plane produced in the mid to far infra-red wavelength range over the past decade. This was done with space telescopes such as the Spitzer, Herschel, and – for longer wavelengths – the Apex itself. However, these projects lacked the speed information that SEDIGISM has now provided. The re-analysis of the data allows a more detailed study of star formation – and thus of the structure and dynamics of the Milky Way itself.

References: (1) F. Schuller et al., “The SEDIGISM survey: first data release and overview of the Galactic structure”, Monthly Notices of the Royal Astronomical Society, 26. November 2020. https://academic.oup.com/mnras/article/500/3/3064/5904091 https://dx.doi.org/10.1093/mnras/staa2369 (2) A Duarte-Cabral, D Colombo, J S Urquhart, A Ginsburg, D Russeil, F Schuller, L D Anderson, P J Barnes, M T Beltrán, H Beuther, S Bontemps, L Bronfman, T Csengeri, C L Dobbs, D Eden, A Giannetti, J Kauffmann, M Mattern, S-N X Medina, K M Menten, M-Y Lee, A R Pettitt, M Riener, A J Rigby, A Traficante, V S Veena, M Wienen, F Wyrowski, C Agurto, F Azagra, R Cesaroni, R Finger, E Gonzalez, T Henning, A K Hernandez, J Kainulainen, S Leurini, S Lopez, F Mac-Auliffe, P Mazumdar, S Molinari, F Motte, E Muller, Q Nguyen-Luong, R Parra, J-P Perez-Beaupuits, F M Montenegro-Montes, T J T Moore, S E Ragan, A Sánchez-Monge, A Sanna, P Schilke, E Schisano, N Schneider, S Suri, L Testi, K Torstensson, P Venegas, K Wang, A Zavagno, The SEDIGISM survey: Molecular clouds in the inner Galaxy, Monthly Notices of the Royal Astronomical Society, , staa2480, https://academic.oup.com/mnras/article-abstract/500/3/3027/5904100?redirectedFrom=fulltext https://doi.org/10.1093/mnras/staa2480 (3) J S Urquhart, C Figura, J R Cross, M R A Wells, T J T Moore, D J Eden, S E Ragan, A R Pettitt, A Duarte-Cabral, D Colombo, F Schuller, T Csengeri, M Mattern, H Beuther, K M Menten, F Wyrowski, L D Anderson, P J Barnes, M T Beltrán, S J Billington, L Bronfman, A Giannetti, J Kainulainen, J Kauffmann, M-Y Lee, S Leurini, S-N X Medina, F M Montenegro-Montes, M Riener, A J Rigby, A Sánchez-Monge, P Schilke, E Schisano, A Traficante, M Wienen, SEDIGISM-ATLASGAL: dense gas fraction and star formation efficiency across the Galactic disc, Monthly Notices of the Royal Astronomical Society, Volume 500, Issue 3, January 2021, Pages 3050–3063, https://academic.oup.com/mnras/article-abstract/500/3/3050/5904087?redirectedFrom=fulltext https://doi.org/10.1093/mnras/staa2512

Provided by Max Planck Society

A New View Of How the Brain Decides To Make An Effort (Neuroscience)

Neuroscientists have provided clear visual evidence that a region of the human brain known as the ventral striatum kicks in during decision-making to weigh the costs versus the benefits of making a physical effort.

Nature Human Behavior published the research by scientists at Emory University. It gives the first detailed view of ventral striatum activity during three phases of effort-based decision-making—the anticipation of initiating an effort, the actual execution of the effort and the reward, or outcome, of the effort.

“It’s important to understand the neural mechanisms underlying motivation,” says Shosuke Suzuki, first author of the study and an Emory graduate student of psychology. “Our work has wide implications for treatment of disorders related to reduced motivation, such as depression, schizophrenia and PTSD. It may also help enhance motivational programs for everything from education to athletics and public health.”

“The willingness to expend effort is something crucial to our survival and something that we use every day,” adds Michael Treadway, senior author of the study and Winship Distinguished Research Professor in Emory’s Department of Psychology and Department of Psychiatry and Behavioral Science. “We’ve identified two closely overlapping, but nevertheless distinct, areas of the ventral striatum involved with different phases of effort-based decision-making. And we’ve provided a concrete neuroimaging tool to measure the sensitivity of signals associated with these phases that others can apply to their own data.”

For example, Treadways says, the new method could provide a window into how a drug is affecting the brains of patients suffering from motivational deficits, compared to controls.

Treadway’s lab focuses on understanding the molecular and circuit-level mechanisms of psychiatric symptoms related to mood disorders, anxiety and decision-making.

The ventral striatum, located deep within the brain’s cerebral hemispheres, is an area associated with movement and mediating rewarding experiences and motivation.

Neuroimaging has consistently shown that the ventral striatum activates during decision-making to encode the potential value of rewards relative to costs, such as wait times and probability. The ventral striatum helps you decide whether to pay more for “next-day” delivery or choose “free, one-week” delivery to receive a package.

Neuroimaging studies had previously failed, however, to detect a strong value signal in the ventral striatum for decisions that require a physical effort. If you want more coffee, but the pot is empty, is it worth getting up and brewing some more?

“It was a mystery why this brain region encoded the value of a reward versus time and probability but did not appear to do so for physical effort,” Suzuki says. “It’s been a paradox in the neuroimaging literature.”

Previous research on rodents showed that the ventral striatum is critical for motivating an animal to work for rewards like food. Animal research also shows evidence for two opposing signals in the ventral striatum. An activation signal prepares an animal to work and a discounting signal helps an animal select rewards that require the least effort. These signals help animals work for what they need, while also making sure they don’t work more than they have to.

The presence of these signals had never been tested in humans. The Emory researchers theorized that as the physical cost to perform a task rises, the activation signal would drive an increase in activity in the ventral striatum, while the discounting signal would drive a decrease. They proposed that the simultaneous firing of these two signals—the cost of effort versus the activation of effort itself—is what made it harder to detect the value signal in previous studies.

An additional complication to detecting brain activation associated with physical effort is the fact that neuroimaging requires participants to lie still within a functional Magnetic Resonance Imaging (fMRI) machine while their brains are scanned.

To get around these issues, the researchers designed fMRI experiments that would allow participants to remain in a supine position and would also separate the neural signals involving effort from the one associated with the cost of the effort.

For the first set of experiments, the researchers created a virtual maze. As their brains were scanned, study participants were presented with maze navigation tasks that required different levels of effort. In one condition, the participants watched themselves move through the virtual maze passively. In another condition, they simply pressed a button on a handheld device to move through the maze. A third condition required the higher effort of repeatedly and rapidly pressing the button to move through the maze. Each maze, when successfully completed, rewarded them with a nominal dollar amount.

During a second experiment, the neural activity of participants was measured as they made a series of choices between two options, with varying amounts of reward and effort required for each option. The effort and reward amounts were presented sequentially to try to isolate the effort-activation signal during the anticipation of various effort demands.

The results showed that two distinct regions of the ventral striatum fired in response to different phases of physical effort and effort-based decision making, with some overlap. Activity in an anterior region was mainly associated with reward and effort costs, while activity in a dorsal region was mainly associated with initiation of effortful movement. And this activity related to effortful movement was distinct from activity in another region, called the putamen, which was associated with initiation of simple movement.

The researchers now hope to build upon this increased awareness for how the brain encodes signals related to motivation.

“Our current paper provides a paradigm for how to measure brain activity for effort-based decisions associated with assigned tasks,” Suzuki says. “Now we’re developing experiments to identify specific modes of signaling when people spontaneously initiate action. That may give us a better measure of how the brain operates when people do things because they want to do them, in real-life situations. Getting sensitive measurements for how people normally decide to expend effort may help us develop better treatments for people suffering motivational deficits related to depression or other illnesses.”

References: Shosuke Suzuki et al. Distinct regions of the striatum underlying effort, movement initiation and effort discounting, Nature Human Behaviour (2020). DOI: 10.1038/s41562-020-00972-y https://www.nature.com/articles/s41562-020-00972-y

Provided by Emory University

Adaptive Image Receive (AIR) Coil Shows Promise For Whole-brain Imaging (Neuroscience)

According to an article in ARRS’ American Journal of Roentgenology (AJR), a prototype 16-channel head Adaptive Image Receive (AIR) radiofrequency coil from GE Healthcare outperformed a conventional 8-channel head coil for in vivo whole-brain imaging, though it did not perform as well as a conventional 32-channel head coil.

Noise covariance matrices for 8-channel (left), 16-channel AIR (middle), and 32-channel (right) head coils. Noise power of each individual element is shown along diagonal, and noise correlation between elements is shown on off-diagonal. Off-diagonal terms are normalized to diagonal term, because relationship of off-diagonal to diagonal terms reflects coupling. Credit: American Roentgen Ray Society (ARRS), American Journal of Roentgenology (AJR)

“This study shows the feasibility of the novel AIR coil technology for imaging the brain and provides insight for future coil design improvements,” concluded first author Petrice M. Cogswell of the Mayo Clinic in Rochester, Minnesota.

Lightweight and flexible with an open, ski-mask design, the emergent AIR coil technology exhibits electrical characteristics that overcome several of the limitations of traditional rigid coil designs.

Imaging a phantom and 15 healthy adult participants, Cogswell and colleagues used clinically available MRI sequences to compare their 16-channel head AIR coil with conventional 8- and 32-channel head coils. During consensus review, two board-certified neuroradiologists graded the AIR coil against the 8-channel coil and the 32-channel coil on a 5-point ordinal scale in multiple categories.

On average, the signal-to-noise ratio, structural sharpness, and overall image quality scores of the 16-channel AIR coil prototype were better than those of the 8-channel coil but not as good as those of the 32-channel coil.

A-C, MPRAGE images obtained with 8-channel (A), 16-channel AIR (B), and 32-channel (C) head coils. Surface coil intensity correction has been applied for these images via vendor-provided algorithm. Nonspecific white matter lesions and perivascular spaces (white arrow) evaluated for scoring of structural sharpness were better depicted on 32-channel relative to 16-channel AIR and on 16-channel relative to 8-channel coil. Frontal signal loss of 16-channel AIR coil is shown by red arrow in B. AIR coil element placement in this prototype was not specifically optimized for uniformity, and this may be improved in future designs. Credit: American Roentgen Ray Society (ARRS), American Journal of Roentgenology (AJR)

Noise covariance matrices showed stable performance of the AIR coil across participants. Overall, the median g-factors for the 16-channel AIR coil were less than those of the 8-channel coil but greater than those of the 32-channel coil.

“The advantages of the AIR coil technology for reduction of claustrophobia, improved airway access and monitoring of patients under anesthesia, and overall better user comfort may be investigated in future studies,” the authors of this AJR article added.

References: Petrice M. Cogswell et al, Application of Adaptive Image Receive Coil Technology for Whole-Brain Imaging, American Journal of Roentgenology (2020). https://www.ajronline.org/doi/10.2214/AJR.20.22812 DOI: 10.2214/AJR.20.22812

Provided by American Roentgen Ray Society

Better Diabetes Treatment: New Insulin Molecule Can Self-regulate Blood Sugar (Medicine)

Everyday life for the more than 46 million people around the world who suffer from type 1 diabetes could become much easier and safer.

Researchers from the University of Copenhagen and biotech firm Gubra have developed a new insulin molecule that, in the future, will ensure that diabetics receive just the right amount of insulin.

The insulin on the market today is unable to identify whether a patient with type 1 diabetes needs a small or large effect from the insulin, which lowers blood sugar.

“That is why we have developed the first step towards a kind of insulin that can self-adjust according to a patient’s blood sugar level. This has tremendous potential to vastly improve the lives of people with type 1 diabetes,” explains Professor Knud J. Jensen, of the University of Copenhagen’s Department of Chemistry, one of the researchers behind a new study on this new insulin.

Effective in rats

The researchers behind the study developed a type of insulin with a built-in molecular-binding that can sense how much blood sugar is in the body. As blood sugar rises, the molecule becomes more active and releases more insulin. As blood sugar drops, less is released.

“The molecule constantly releases a small amount of insulin, but varies according to need,” says Knud J. Jensen, who continues:

“It will give type 1 diabetes patients a safer and easier treatment. Today, a person with type 1 diabetes must inject themselves with insulin many times throughout the day and frequently monitor their blood sugar level by pricking their finger with a blood glucose meter. This here, allows a person to inject the new insulin molecule less often over the course of a day and thereby think about it less,” says Knud J. Jensen.

Although the new ‘automated’ insulin is a major advance towards better diabetes treatment, it will be a while before the revolutionary insulin becomes a part of diabetics’ everyday lives.

“We’ve tested the insulin molecule on rats and it has proven itself effective. The next step is to develop the molecule so that it works more rapidly and accurately. And finally, to test it in humans—a process that can take many years. But it is certainly worth pinning one’s hopes on,” explains Professor Jensen.

An idea that sprouted in the United States

The idea to create a kind of insulin that self-adjusts to a patient’s needs occurred many years ago, while Professor Jensen was living in the United States. This is where a friend of his with type 1 diabetes recounted to him a story:

“My author friend Jan Sonnergaard told me about a married couple who had been dancing one night. The man had type 1 diabetes and was feeling unwell. The wife thought to stabilize his blood sugar by giving him insulin. Unfortunately, the insulin eventuated in her husband’s death. I wanted to make certain that this kind of tragedy would never be repeated,” says Knud J. Jensen, concluding:

“The difficult thing with diabetes is that insulin always works the same way. It lowers blood sugar, even though that might not be what a patient requires. This is what we seek to address with our new molecule.”

References: Jensen, K..J., Mannerstedt, K., MIshra, N..K., Engholm, E., Lundh, M., Madsen, C..S., Pedersen, P..J., Le-Huu, P., Pedersen, S..L., Buch-Månson, N., Borgström, B., Brimert, T., Fink, L..N., Fosgerau, K. and Vrang, N. (2020), An Aldehyde Responsive, Cleavable Linker for Glucose Responsive Insulins. Chem. Eur. J.. Accepted Author Manuscript. https://doi.org/10.1002/chem.202004878 https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202004878

Provided by University of Copenhagen

What Makes Psoriasis Sore: Novel Role of Immune System In the Disease (Medicine)

More than 130 million people around the globe suffer from psoriasis vulgaris, a chronic condition characterized by skin inflammation, scales, and dry patches. However, its pathology is not fully clear. In a recent study, dermatology researchers at Fujita Health University have uncovered a complex cellular mechanism responsible for the onset of psoriasis and highlighted potential therapeutic targets for future treatment.

Microscopic observations of the back skins of two mice—one with the IL-36 deficiency and another wild type—after topical application of psoriasis-inducing imiquimod show that the former developed psoriasis like lesions after 3 days of application. They also showed greater neutrophil infiltration. Credit: Kazumitsu Sugiura from Fujita Health University

Psoriasis has always been a common disease. Historically, its causes were obscure and surrounded by stigma; it wasn’t until recently that scientists categorized it as an autoimmune condition. Indeed, modern scientific research shows that the body’s own T-cells, macrophages and dendritic cells are responsible for attacking healthy skin tissue, triggering inflammation and proliferation of skin cells, and resulting in the characteristic red, painful plaque-like lesions experienced by psoriasis patients.

But although these immune-mediating cells have been identified as the primary culprits for the breakdown of healthy skin, their roles do not fully clarify the underlying cause. What makes these cells behave so abnormally?

Based on their existing knowledge of the cellular and genetic pathways linked with the disease, Professor Kazumitsu Sugiura and Dr. Soichiro Watanabe from Fujita Health University, Japan, along with their colleagues, attempted to find out. Their study helped them clarify the role of another potential culprit in the formation of psoriasis lesions: neutrophils. Their findings are published in Scientific Reports.

The most common type of white blood cell, neutrophils are known to be associated with various other chronic and autoimmune conditions, such as rheumatoid arthritis and lupus. Neutrophils have pro-inflammatory effects: once activated, they travel to the site of infection and effectively undergo cell death. During this process, they burst open and release their contents, forming what scientists call “neutrophil extracellular traps” (NETs), a web of proteins and genetic information from the nucleus of the former cell.

NETs have reportedly been found in psoriasis lesions. However, the mechanisms linking the formation of NETs and severe skin inflammation are unknown. Prof Sugiura explains: “NETs and neutrophils can induce inflammation through various mechanisms; we aim to clarify the role of NET signaling and possibly prevent the development of severe psoriasis-like lesions”.

A precursor to the activation of NETs in psoriasis is a group of signaling proteins called IL-36 cytokines, whose role in recruiting various white blood cells and inducing inflammation is well acknowledged. For instance, a mutation in the Il36rn gene that causes a deficiency of the IL-36 receptor antagonist (IL-36Ra) protein, allows IL-36 to act uninhibited, leading to inflammation, inducing the proliferation of epidermal cells and increasing neutrophil count in psoriasis-like lesions in the mutant mice, in a condition known as DITRA. This results in skin cells keratinizing (hardening) in the manner seen in psoriasis lesions.

Armed with this theoretical knowledge, Prof. Sugiura and team studied two groups of mice: one healthy (wild type) and another with the aforementioned Il36rn gene mutation. They induced psoriasis-like lesions using imiquimod, a drug known to stimulate IL-36 signaling and subsequent immunological response. After examining the lesions, they found that mutant mice suffered more severe inflammation than the wild type. A more detailed histological analysis revealed that the mutant mice also had significantly higher neutrophil counts and NET concentrations than the wild type. The scientists went one step further and examined the mRNA levels of target cytokines known to be involved in psoriasis formation to elucidate the IL-36 pathway, thereby linking cause and effect.

Having identified these complex cellular mechanics, the scientists made a list of potential targets to block the inflammation pathway and prevent psoriasis. They injected the diseased mice with Cl-amidine, a drug which specifically targets and inhibits PAD4—an enzyme responsible for the formation of NETs. After only three days of treatment, they found the lesions, as well as the levels of inflammatory cells and IL-36 signaling proteins, significantly reduced.

Although further research and human clinical trials will be required to confirm the safety and effectiveness of potential psoriasis treatments, Prof. Sugiura and his colleagues are hopeful. Dr. Soichiro Watanabe says, “By providing mechanistic insights into the involvement of neutrophils in psoriasis pathogenesis, our study provides new directions for developing novel promising therapeutic approaches, potentially revolutionizing the quality of life of thousands of people suffering from particularly severe forms of psoriasis.”

References: Watanabe, S., Iwata, Y., Fukushima, H. et al. Neutrophil extracellular traps are induced in a psoriasis model of interleukin-36 receptor antagonist-deficient mice. Sci Rep 10, 20149 (2020). https://www.nature.com/articles/s41598-020-76864-y https://doi.org/10.1038/s41598-020-76864-y

Provided by Fujita Health University

Researchers Publish the First Study On The Metagenomics of Dental Black Plaque in Adults (Dentistry / Medicine)

The dark pigmentations that appear around the gums on dental enamel have a bacterial origin and there is currently no definitive therapy to remove it entirely. In order to find the best way to fight against the creation of these black stains on teeth, the Oral Microbiology Group of the CEU Cardenal Herrera University (CEU UCH) of Valencia, Spain, has conducted the first study in the world with adults on the metagenomics of dental black plaque, in collaboration with company Microomics Systems S.L, whose headquarters are in Barcelona. “Although in previous studies we assessed the efficiency of phototherapy in the treatment of these stains on the enamel, knowing the metagenomics of this type of dark plaque of bacterial origin will allow us to progress in finding definitive treatments for its removal,” highlight the study authors.

Credit: Asociación RUVID

In their work, published in journal Scientific Reports, the CEU UCH and Microomics Systems researchers have described and compared the microbial diversity of dental white plaque and the black stains that appear on them, on a total 27 volunteer adults, all of which are receiving treatment at the University Dental Clinic of the CEU UCH in Valencia. The characterisation of the taxonomic profile of the samples and comparing the microbiomes of white and black dental plaque is a study that had only been performed on children, who most often suffer from these types of stains.

First map of the microbiome of dental black plaque

With this data, the CEU UCH team has created the first map of the microbiome of dental black plaque in adults, finding that the variety of bacterial species is lower than in dental white plaque. The five most common bacterial species found in the dental black plaque of the adults studies were from the Capnocytophaga, Leptotrichia, Fusobacterium, Corynebacterium and Streptococcus genuses. The study also made it possible to detect the existence of functional routes among the microbiomes of white and black dental plaque.

“We have found that the key for the formation of dental black plaque are the routes of biosynthetic compounds of the heme group, which would explain the black color,” highlight the researchers. The sequestration of iron by the bacteria of the black plaque and its subsequent metabolism towards biosynthetic routes of the heme group are essential for the formation of this type of plaque, the study reveals. This finding, along with new research for its complete description, will make it possible to progress in the designing of treatments that prevent the appearance of dental black plaque in the most effective way.

The Oral Microbiology Group of the CEU UCH published in 2018 a pioneering study on the use of antimicrobial phototherapy to fight, with light and oxygen, against the proliferation of the bacteria that cause the black stains on enamel or dental black plaque. Using a household tooth whitening device, they managed to decrease the size, color and bacterial colonization of the dental black plaque closest to the gums in the group of patients who took part in the test. In prior studies they also analyzed the risk factors for the appearance of these black stains, such as water with high iron contents of high pH, which is why they recommend consuming mineral water instead of tap water or osmosis water for people who are prone to having these black pigmentations appear on their enamel.

References: Veses, V., González-Torres, P., Carbonetto, B. et al. Dental black plaque: metagenomic characterization and comparative analysis with white-plaque. Sci Rep 10, 15962 (2020). https://www.nature.com/articles/s41598-020-72460-2 https://doi.org/10.1038/s41598-020-72460-2

Provided by Asociacion RUVID

Gastric Bypass Surgery Leads to Long-term Diabetes Remission (Medicine)

More than half of adults with type 2 diabetes had long-term remission following gastric bypass surgery, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

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Bariatric surgery helps people with severe obesity lose a lot of weight and improve their health. Two common types of bariatric surgery are lap band surgery, which places a band around the top of the stomach to create a very small pouch that can hold only a small amount of food, and gastric bypass, which reduces the size of the stomach, causes hormonal changes, and can lower the amount of nutrients that are absorbed from food. One of the biggest benefits of bariatric surgery is that it can improve or eliminate type 2 diabetes.

“If a patient with type 2 diabetes is considering weight loss surgery, choosing gastric bypass soon after diagnosis can increase their chance of remission or achieving a blood sugar level that does not need treatment,” said study author Jonathan Q. Purnell, M.D., of the Oregon Health & Science University in Portland, Ore. “Our large study confirms the importance of weight loss on inducing diabetes remission, but also finds gastric bypass has benefits independent of weight. If we can understand what these benefits are, it could lead to new diabetes treatments.”

The researchers studied 2,256 adults with severe obesity (a BMI of at least 35 kg/m²) who completed annual research assessments for up to seven years after bariatric surgery, roughly 35 percent of whom had type 2 diabetes. Fifty seven percent of participants with diabetes achieved remission after gastric bypass surgery, and 22 percent reached remission after lap band surgery. For both procedures, remission was more common in younger participants and those who had diabetes for a shorter time prior to their procedure. The researchers found a greater likelihood of diabetes remission after gastric bypass independent of weight loss, suggesting mechanisms beyond weight loss are contributing to improved blood sugar levels.

References: Jonathan Q Purnell, MD, Elizabeth N Dewey, MS, Blandine Laferrère, MD, Faith Selzer, PhD, David R Flum, MD, MPH, James E Mitchell, MD, Alfons Pomp, MD, Walter J Pories, MD, Thomas Inge, MD, PhD, Anita Courcoulas, MD, Bruce M Wolfe, MD, Diabetes Remission Status During Seven-year Follow-up of the Longitudinal Assessment of Bariatric Surgery Study, The Journal of Clinical Endocrinology & Metabolism, , dgaa849, https://academic.oup.com/jcem/advance-article/doi/10.1210/clinem/dgaa849/6006261 https://doi.org/10.1210/clinem/dgaa849

Provided by The Endocrine Society