PTSD link to pandemic fears — ScienceDaily


Even at the start of the COVID-19 pandemic last year, people around the world became more fearful of what could happen to them or their family.

A new Flinders University study of 1040 online participants from five western countries published in PLOS ONE explores people’s response to the stresses of the escalating pandemic, finding more than 13% of the sample had post-traumatic stress disorder (PTSD) related symptoms consistent with levels necessary to qualify for a clinical diagnosis.

With ongoing economic and social fallout, and death toll of more than 2 million, the team of psychology researchers warn more needs to be done to cope with the potential short and long-term spike in PTSD cases resulting from the pandemic — as well as related mental health problems such as anxiety, depression, psychosocial functioning, etc.

“While the global pandemic does not fit into prevailing PTSD models, or diagnostic criteria, our research shows this ongoing global stressor can trigger traumatic stress symptoms,” says lead researcher Associate Professor Melanie Takarangi, from Flinders Psychology.

“We found that traumatic stress was related to future events, such as worry about oneself or a family member contracting COVID-19, to direct contact with the virus, as well as indirect contact such as via the news and government lockdown — a non-life threatening event,” says co-author Victoria Bridgland, who is undertaking a PhD studying the triggers of PTSD.

PTSD is a set of reactions, including intrusive recollections such as flashbacks, that can develop in people exposed to an event that threatened their life or safety (e.g., sexual assault, natural disaster).

“Our findings highlight the need to focus on the acute psychological distress — including the perceived emotional impact of particular events — associated with COVID-19 and build on other research from the past year that demonstrates the damaging psychological impact of COVID-19 on mental health,” says Ms Bridgland.

Comprehensive long-term documentation of COVID-19 related traumatic stress reactions will allow health professionals to help people who could otherwise fall through the cracks, the research team concludes.

The online survey examined a range of responses to common post-traumatic stress symptoms, such as repeated disturbing and unwanted images, memories or thoughts about the COVIC-19 pandemic.

COVID-19’s psychological fallout has been dubbed the “second curve,” predicted to last for months to years, the paper notes.

“Notably, while most of our participants reported experiencing some form of psychological distress and 13.2% of our sample were likely PTSD positive when anchoring symptoms to COVID-19, only 2% of our total sample reported they had personally tested positive to COVID-19, and only 5% reported that close family and friends had tested positive.

“It therefore seems likely that the psychological fallout from COVID-19 may reach further than the medical fallout,” the paper concludes.

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Researchers identify important function of the so-called oligodendrocytes — ScienceDaily


The human brain has about as many neurons as glial cells. These are divided into four major groups: the microglia, the astrocytes, the NG2 glial cells, and the oligodendrocytes. Oligodendrocytes function primarily as a type of cellular insulating tape: They form long tendrils, which consist largely of fat-like substances and do not conduct electricity. These wrap around the axons, which are the extensions through which the nerve cells send their electrical impulses. This prevents short circuits and accelerates signal forwarding.

Astrocytes, on the other hand, supply the nerve cells with energy: Through their appendages they come into contact with blood vessels and absorb glucose from these. They then transport it to the interfaces between two neurons, the synapses. Before that, they partially convert the sugar into other energy-rich molecules. “We have now been able to show that oligodendrocytes play an important role in the distribution of these compounds,” explains Prof. Christian Steinhäuser from the Institute of Cellular Neurosciences at the University of Bonn (Germany). “This is apparently especially true in a particular brain region, the thalamus.”

Huge supply network

The thalamus is also called the “gateway to consciousness.” The sensory signals it receives include those from the ears, eyes, and skin. It then forwards them to the respective responsible centers of the cerebral cortex. Only then do we become aware of this information, for instance the sound of an instrument.

It has long been known that astrocytes can form close connections: They build intercellular networks through tunnel-like coupling. Molecules can migrate from one cell to another through these “gap junctions.” A few years ago, Steinhäuser and his colleagues were able to show that there are also oligodendrocytes in these networks in the thalamus, about as many as astrocytes. The cells form a huge network in this way, which neuroscientists also call a “panglial network” (“pan” comes from Greek and means “comprehensive”). In other regions, however, the networks consist predominantly of coupled astrocytes. “We wanted to know why this is different here,” explains Dr. Camille Philippot of Steinhäuser’s research group, who conducted much of the work. “Our results demonstrate that the high-energy compounds travel through this network from the blood vessels to the synapses,” Philippot emphasizes. “And oligodendrocytes seem to be indispensable in this process.”

The researchers were for instance able to demonstrate this in mice, in which the oligodendrocytes are unable to participate in the network because they lack the appropriate tunnels. In these mice, energy molecules no longer reached the synapses in sufficient quantities. The same was true if the astrocytes lacked the appropriate connecting links. “The thalamus apparently requires both cell types for transport,” Steinhäuser concludes.

Starved neurons cannot communicate

The researchers were also able to show the consequences of such a disrupted energy supply for neuronal information processing. The synapses are where two neurons meet — a sender cell and a receiver cell. When a pulse from the sender cell arrives at the synapse, it releases messenger molecules into the synaptic cleft. These neurotransmitters dock onto the recipient cell and trigger electrical signals there, the postsynaptic potentials. When these signals are generated, potassium and sodium ions pass through the membrane of the recipient cell — sodium ions inward, potassium ions outward. These, like the neurotransmitters, must then be pumped back again. “And for that, the neurons need energy,” explains Steinhäuser, who is also a member of the Transdisciplinary Research Area “Life and Health” at the University of Bonn. “When energy is lacking, pumping activity ceases.” In the experiments, “starved” neurons were therefore no longer able to generate postsynaptic activity after just a few minutes.

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Delivering drug straight to the brain could cut required dose by as much as 75 per cent — ScienceDaily


A team of neuroscientists and engineers at McMaster University has created a nasal spray to deliver antipsychotic medication directly to the brain instead of having it pass through the body.

The leap in efficiency means patients with schizophrenia, bipolar disorder and other conditions could see their doses of powerful antipsychotic medications cut by as much as three quarters, which is expected to spare them from sometimes-debilitating side effects while also significantly reducing the frequency of required treatment.

The new method delivers medication in a spray that reaches the brain directly through the nose, offering patients greater ease of use and the promise of improved quality of life, including more reliable, effective treatment.

Ram Mishra, a Professor in the Department of Psychiatry and Behavioural Neurosciences and Co-Director of McMaster’s School of Biomedical Engineering, and Todd Hoare, a Canada Research Chair and Professor of Chemical Engineering, describe their research in a newly published article in the Journal of Controlled Release.

They and their co-authors Michael Majcher, Ali Babar, Andrew Lofts, and Fahed Abuhijleh have proven the concept of their new delivery mechanism in rats, using PAOPA, a drug commonly prescribed to treat schizophrenia.

A problem for patients using antipsychotic medications, Mishra explains, is that taking them orally or by injection means the drugs must pass through the body before they reach the brain through the blood. To be sure enough oral or injected medication reaches the brain, a patient must take much more than the brain will ultimately receive, leading to sometimes serious adverse side effects, including weight gain, diabetes, drug-induced movement disorders and organ damage over the long term.

When delivered through the nose, the spray medication can enter the brain directly via the olfactory nerve.

“The trick here is to administer the drug through the back door to the brain, since the front door is sealed so tightly,” Mishra says. “This way we can bypass the blood-brain barrier. By delivering the drug directly to the target, we can avoid side effects below the brain.”

Mishra and collaborator Rodney Johnson of the University of Minnesota had previously created a water-soluble form of the medication, which was used in the current research. The new form they created was easier to manipulate, but they still lacked an effective vehicle for getting it to the brain. A particular issue was that drugs delivered via the nose are typically cleared from the body quickly, requiring frequent re-administration.

Hoare, in the meantime, had been working with an industrial partner to develop the use microscopic nanoparticles of corn starch for agricultural applications.

The two scientists, who work across campus from one another, came together after researchers in their labs met at an internal McMaster conference. Two of the researchers, Babar and Lofts, worked on the project in both labs.

The engineering team was able to bind the drug to the corn starch nanoparticles that, when sprayed together with a natural polymer derived from crabs, could penetrate deep into the nasal cavity and form a thin gel in the mucus lining, slowly releasing a controlled dose of the drug, which remains effective for treating schizophrenia symptoms over three days.

“The cornstarch nanoparticles we were using for an industrial application were the perfect vehicle,” Hoare says. “They are naturally derived, they break down over time into simple sugars, and we need to do very little chemistry on them to make this technology work, so they are great candidates for biological uses like this.”

The gradual release means patients would only need to take their medication every few days instead of every day or, in some cases, every few hours.

The research work was funded by a Collaborative Health Research Partnership Grant (from the Natural Sciences and Engineering Research Council of Canada and the Canadian Institutes of Health Research) and McMaster University’s Interdisciplinary Research Fund.

The researchers are seeking a corporate partner to move the technology into the marketplace.

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Compound from medicinal herb kills brain-eating amoebae in lab studies — ScienceDaily


Primary amoebic meningoencephalitis (PAM), a deadly disease caused by the “brain-eating amoeba” Naegleria fowleri, is becoming more common in some areas of the world, and it has no effective treatment. Now, researchers reporting in ACS Chemical Neuroscience have found that a compound isolated from the leaves of a traditional medicinal plant, Inula viscosa or “false yellowhead,” kills the amoebae by causing them to commit cell suicide in lab studies, which could lead to new treatments.

PAM, characterized by headache, fever, vomiting, hallucinations and seizures, is almost always fatal within a couple of weeks of developing symptoms. Although the disease, which is usually contracted by swimming in contaminated freshwater, is rare, increasing cases have been reported recently in the U.S., the Philippines, southern Brazil and some Asian countries. Amphotericin B is the most common therapy given to those with the infection. It can kill N. fowleri in the lab, but it isn’t very effective when given to patients, likely because it cannot cross the blood-brain barrier. Ikrame Zeouk, José Piñero, Jacob Lorenzo-Morales and colleagues wanted to explore whether compounds isolated from I. viscosa, a strong-smelling plant that has long been used for traditional medicine in the Mediterranean region, could effectively treat PAM.

The researchers first made an ethanol extract from the herb’s leaves, finding that it could kill N. fowleri amoebae. Then, they isolated and tested specific compounds from the extract. The most potent compound, inuloxin A, killed amoebae in the lab by disrupting membranes and causing mitochondrial changes, chromatin condensation and oxidative damage, ultimately forcing the parasites to undergo programmed cell death, or apoptosis. Although inuloxin A was much less potent than amphotericin B in the lab, the structure of the plant-derived compound suggests that it might be better able to cross the blood-brain barrier. More studies are needed to confirm this hypothesis, the researchers say.

The authors acknowledge funding from the European Regional Development Fund, the Spanish Ministry of Economic Affairs and Digital Transformation, the Spanish Ministry of Science, Innovation and Universities, the University of La Laguna and the Augustin de Betancourt Foundation.

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Earth to reach temperature tipping point in next 20 to 30 years, new study finds — ScienceDaily


Earth’s ability to absorb nearly a third of human-caused carbon emissions through plants could be halved within the next two decades at the current rate of warming, according to a new study in Science Advances by researchers at Northern Arizona University, the Woodwell Climate Research Center and the University of Waikato, New Zealand. Using more than two decades of data from measurement towers in every major biome across the globe, the team identified a critical temperature tipping point beyond which plants’ ability to capture and store atmospheric carbon — a cumulative effect referred to as the “land carbon sink” — decreases as temperatures continue to rise.

The terrestrial biosphere — the activity of land plants and soil microbes — does much of Earth’s “breathing,” exchanging carbon dioxide and oxygen. Ecosystems across the globe pull in carbon dioxide through photosynthesis and release it back to the atmosphere via the respiration of microbes and plants. Over the past few decades, the biosphere has generally taken in more carbon than it has released, mitigating climate change.

But as record-breaking temperatures continue to spread across the globe, this may not continue; the NAU, Woodwell Climate and Waikato researchers have detected a temperature threshold beyond which plant carbon uptake slows and carbon release accelerates.

Lead author Katharyn Duffy, a postdoctoral researcher at NAU, noticed sharp declines in photosynthesis above this temperature threshold in nearly every biome across the globe, even after removing other effects such as water and sunlight.

“The Earth has a steadily growing fever, and much like the human body, we know every biological process has a range of temperatures at which it performs optimally, and ones above which function deteriorates,” Duffy said. “So, we wanted to ask, how much can plants withstand?”

This study is the first to detect a temperature threshold for photosynthesis from observational data at a global scale. While temperature thresholds for photosynthesis and respiration have been studied in the lab, the Fluxnet data provide a window into what ecosystems across Earth are actually experiencing and how they are responding.

“We know that the temperature optima for humans lie around 37 degrees Celsius (98 degrees Fahrenheit), but we in the scientific community didn’t know what those optima were for the terrestrial biosphere,” Duffy said.

She teamed up with researchers at Woodwell Climate and the University of Waikato who recently developed a new approach to answer that question: MacroMolecular Rate Theory (MMRT). With its basis in the principles of thermodynamics, MMRT allowed the researchers to generate temperature curves for every major biome and the globe.

The results were alarming.

The researchers found that temperature “peaks” for carbon uptake — 18 degrees C for the more widespread C3 plants and 28 degrees C for C4 plants — are already being exceeded in nature, but saw no temperature check on respiration. This means that in many biomes, continued warming will cause photosynthesis to decline while respiration rates rise exponentially, tipping the balance of ecosystems from carbon sink to carbon source and accelerating climate change.

“Different types of plants vary in the details of their temperature responses, but all show declines in photosynthesis when it gets too warm,” said NAU co-author George Koch.

Right now, less than 10 percent of the terrestrial biosphere experiences temperatures beyond this photosynthetic maximum. But at the current rate of emissions, up to half the terrestrial biosphere could experience temperatures beyond that productivity threshold by mid-century — and some of the most carbon-rich biomes in the world, including tropical rainforests in the Amazon and Southeast Asia and the Taiga in Russia and Canada, will be among the first to hit that tipping point.

“The most striking thing our analysis showed is that the temperature optima for photosynthesis in all ecosystems were so low,” said Vic Arcus, a biologist at the University of Waikato and co-author of the study. “Combined with the increased rate of ecosystem respiration across the temperatures we observed, our findings suggest that any temperature increase above 18 degrees C is potentially detrimental to the terrestrial carbon sink. Without curbing warming to remain at or below the levels established in the Paris Climate Accord, the land carbon sink will not continue to offset our emissions and buy us time.”

Funding for this research was provided by the National Aeronautics and Space Administration (grant NNX12AK12G), National Science Foundation (NSF) East-Asia Pacific Summer Institute Fellowship (1614404), the Royal Society of New Zealand Foreign Partnership Programme (EAP- UOW1601) and the New Zealand Marsden Fund (grant 16-UOW-027). This work used eddy covariance data acquired and shared by the FLUXNET community, including AmeriFlux, AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, Fluxnet-Canada, GreenGrass, ICOS, KoFlux, LBA, NECC, OzFlux-TERN, TCOS-Siberia and USCCC networks.

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We hear what we expect to hear — ScienceDaily


Humans depend on their senses to perceive the world, themselves and each other. Despite senses being the only window to the outside world, people do rarely question how faithfully they represent the external physical reality. During the last 20 years, neuroscience research has revealed that the cerebral cortex constantly generates predictions on what will happen next, and that neurons in charge of sensory processing only encode the difference between our predictions and the actual reality.

A team of neuroscientists of TU Dresden headed by Prof Dr Katharina von Kriegstein presents new findings that show that not only the cerebral cortex, but the entire auditory pathway, represents sounds according to prior expectations.

For their study, the team used functional magnetic resonance imaging (fMRI) to measure brain responses of 19 participants while they were listening to sequences of sounds. The participants were instructed to find which of the sounds in the sequence deviated from the others. Then, the participants’ expectations were manipulated so that they would expect the deviant sound in certain positions of the sequences. The neuroscientists examined the responses elicited by the deviant sounds in the two principal nuclei of the subcortical pathway responsible for auditory processing: the inferior colliculus and the medial geniculate body. Although participants recognised the deviant faster when it was placed on positions where they expected it, the subcortical nuclei encoded the sounds only when they were placed in unexpected positions.

These results can be best interpreted in the context of predictive coding, a general theory of sensory processing that describes perception as a process of hypothesis testing. Predictive coding assumes that the brain is constantly generating predictions about how the physical world will look, sound, feel, and smell like in the next instant, and that neurons in charge of processing our senses save resources by representing only the differences between these predictions and the actual physical world.

Dr Alejandro Tabas, first author of the publication, states on the findings: “Our subjective beliefs on the physical world have a decisive role on how we perceive reality. Decades of research in neuroscience had already shown that the cerebral cortex, the part of the brain that is most developed in humans and apes, scans the sensory world by testing these beliefs against the actual sensory information. We have now shown that this process also dominates the most primitive and evolutionary conserved parts of the brain. All that we perceive might be deeply contaminated by our subjective beliefs on the physical world.”

These new results open up new ways for neuroscientists studying sensory processing in humans towards the subcortical pathways. Perhaps due to the axiomatic belief that subjectivity is inherently human, and the fact that the cerebral cortex is the major point of divergence between the human and other mammal’s brains, little attention has been paid before to the role that subjective beliefs could have on subcortical sensory representations.

Given the importance that predictions have on daily life, impairments on how expectations are transmitted to the subcortical pathway could have profound repercussion in cognition. Developmental dyslexia, the most wide-spread learning disorder, has already been linked to altered responses in subcortical auditory pathway and to difficulties on exploiting stimulus regularities in auditory perception. The new results could provide with a unified explanation of why individuals with dyslexia have difficulties in the perception of speech, and provide clinical neuroscientists with a new set of hypotheses on the origin of other neural disorders related to sensory processing.

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Neuronal circuits for fine motor skills — ScienceDaily


Writing, driving a screw or throwing darts are only some of the activities that demand a high level of skill. How the brain masters such exquisite movements has now been described in the journal “Nature” by a team of researchers at the University of Basel and the Friedrich Miescher Institute for Biomedical Research. A map of brainstem circuits reveals which neurons control the fine motor skills of the arm and hand.

Picking up a pen and writing our name or reaching for a fork to eat spaghetti with tomato sauce are things we take for granted. However, holding a pen properly or bringing spaghetti to the mouth without making a mess requires precise arm movements and a high level of skill.

Underlying all our motor behavior is a perfect interplay between neurons in the brain, the spinal cord, and the muscles. But which neuronal circuits control the fine motor skills of the arms, hands and fingers? Prof. Silvia Arber’s team has been addressing this question in recent work. The neurobiologists who work at both the Biozentrum of the University of Basel and at the Friedrich Miescher Institute for Biomedical Research (FMI) have been investigating how the nervous system controls motor behavior for many years.

Neurons in the brainstem control fine motor skills

Using a mouse model, the researchers have been able to demonstrate that a specific region of the brainstem is responsible for various fine motor activities of the forelimbs. For their investigations they applied so-called optogenetic and viral methods in order to mark neurons and observe their activity. This enabled the team to localize four neuronal subpopulations in this region and correlate with specific functions. For example, one group of neurons was able to elicit forelimb reaching, while another group controls handling of the food.

In terms of evolution, the brainstem is the oldest part of the brain and is the direct extension of the spinal cord. The brainstem is an important switchboard between higher order movement planning centers in the brain and the executive circuits in the spinal cord. In the spinal cord, information streams about movement ultimately reach motor neurons that are directly connected to muscles cells. These in turn control movement through contraction. It has only recently been discovered that the brainstem consists of many areas containing functionally specialized neuronal populations, engaged with the control of diverse forms of body movements.

Map of brainstem circuits for fine motor skills

In their study, Arber’s team has defined the organization of the neurons in one of those brainstem regions called the “lateral rostral medulla” (latRM) and traced their communication pathways. This enabled the researchers to associate different behavioral activities with specific groups of latRM neurons. “Relatively simple forelimb actions such as reaching for food are accomplished by latRM neurons with direct projections to the spinal cord,” explains the first author Ludwig Ruder.

Executing more complex forelimb movements, which also involve the fingers, i.e. grasping or bringing a piece of food to the mouth, are controlled by latRM neurons with connections to neurons in other brainstem regions. “The connections and circuits within the brainstem are indispensable for more complex motor skills,” says Arber. “The neuronal populations we identified in the latRM very specifically control motor skills of the forelimbs. Notably, the generation of complex and precise forelimb movements such as throwing, grasping or writing require the communication between different brainstem regions.”

Control of motor actions is similar in man and animals

The division of neuronal populations according to different forms of movements based on spatial organization and connectivity provides insights into the function of the brainstem and the control of motor behavior, in this case fine motor skills of the arm and hand. Many neuronal circuits of the brainstem are similar in humans and animals. It is therefore possible to hypothesize which neuronal populations control which movements or how diseases or injury may impair fine motor skills or other behaviors in humans.

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Gum disease-causing bacteria borrow growth molecules from neighbors to thrive — ScienceDaily


The human body is filled with friendly bacteria. However, some of these microorganisms, such as Veillonella parvula, may be too nice. These peaceful bacteria engage in a one-sided relationship with pathogen Porphyromonas gingivalis, helping the germ multiply and cause gum disease, according to a new University at Buffalo-led study.

The research sought to understand how P. gingivalis colonizes the mouth. The pathogen is unable to produce its own growth molecules until it achieves a large population in the oral microbiome (the community of microorganisms that live on and inside the body).

The answer: It borrows growth molecules from V. parvula, a common yet harmless bacteria in the mouth whose growth is not population dependent.

In a healthy mouth, P. gingivalis makes up a miniscule amount of the bacteria in the oral microbiome and cannot replicate. But if dental plaque is allowed to grow unchecked due to poor oral hygiene, V. parvula will multiply and eventually produce enough growth molecules to also spur the reproduction of P. gingivalis.

More than 47% of adults 30 and older have some form of periodontitis (also known as gum disease), according to the Centers for Disease Control and Prevention. Understanding the relationship between P. gingivalis and V. parvula will help researchers create targeted therapies for periodontitis, says Patricia Diaz, DDS, PhD, lead investigator on the study and Professor of Empire Innovation in the UB School of Dental Medicine.

“Having worked with P. gingivalis for nearly two decades, we knew it needed a large population size to grow, but the specific processes that drive this phenomenon were not completely understood,” says Diaz, also director of the UB Microbiome Center. “Successfully targeting the accessory pathogen V. parvula should prevent P. gingivalis from expanding within the oral microbial community to pathogenic levels.”

The study, which was published on Dec. 28 in the ISME Journal, tested the effects of growth molecules exuded by microorganisms in the mouth on P. gingivalis, including molecules from five species of bacteria that are prevalent in gingivitis, a condition that precedes periodontitis.

Of the bacteria examined, only growth molecules secreted by V. parvula enabled the replication of P. gingivalis, regardless of the strain of either microbe. When V. parvula was removed from the microbiome, growth of P. gingivalis halted. However, the mere presence of any V. parvula was not enough to stimulate P. gingivalis, as the pathogen was only incited by a large population of V. parvula.

Data suggest that the relationship is one-directional as V. parvula received no obvious benefit from sharing its growth molecules, says Diaz.

“P. gingivalis and V. parvula interact at many levels, but the beneficiary is P. gingivalis,” says Diaz, noting that V. parvula also produces heme, which is the preferred iron source for P. gingivalis.

“This relationship that allows growth of P. gingivalis was not only confirmed in a preclinical model of periodontitis, but also, in the presence of V. parvula, P. gingivalis could amplify periodontal bone loss, which is the hallmark of the disease,” says George Hajishengallis, DDS, PhD, co-investigator on the study and Thomas W. Evans Centennial Professor in the University of Pennsylvania School of Dental Medicine.

“It is not clear whether the growth-promoting cues produced by P. gingivalis and V. parvula are chemically identical,” says Diaz. “Far more work is needed to uncover the identity of these molecules.”

Additional investigators include Anilei Hoare, PhD, assistant professor, University of Chile; Hui Wang, PhD, postdoctoral researcher, University of Pennsylvania; Archana Meethil, resident, University of Connecticut; Loreto Abusleme, PhD, assistant professor, University of Chile; Bo-Young Hong, PhD, associate research scientist, Jackson Laboratory for Genomic Medicine; Niki Moutsopoulos, DDS, PhD, senior investigator, National Institute of Dental and Craniofacial Research; and Philip Marsh, PhD, professor, University of Leeds.

The research was funded by the National Institute of Dental and Craniofacial Research of the National Institutes of Health.

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Brain volume measurement may provide early biomarker — ScienceDaily


Posttraumatic stress disorder (PTSD) is a complex psychiatric disorder brought on by physical and/or psychological trauma. How its symptoms, including anxiety, depression and cognitive disturbances arise remains incompletely understood and unpredictable. Treatments and outcomes could potentially be improved if doctors could better predict who would develop PTSD. Now, researchers using magnetic resonance imaging (MRI) have found potential brain biomarkers of PTSD in people with traumatic brain injury (TBI).

The study appears in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier.

“The relationship between TBI and PTSD has garnered increased attention in recent years as studies have shown considerable overlap in risk factors and symptoms,” said lead author Murray Stein, MD, MPH, FRCPC, a Distinguished Professor of Psychiatry and Family Medicine & Public Health at the University of California San Diego, San Diego, La Jolla, CA, USA. “In this study, we were able to use data from TRACK-TBI, a large longitudinal study of patients who present in the Emergency Department with TBIs serious enough to warrant CT (computed tomography) scans.”

The researchers followed over 400 such TBI patients, assessing them for PTSD at 3 and 6 months after their brain injury. At 3 months, 77 participants, or 18 percent, had likely PTSD; at 6 months, 70 participants or 16 percent did. All subjects underwent brain imaging after injury.

“MRI studies conducted within two weeks of injury were used to measure volumes of key structures in the brain thought to be involved in PTSD,” said Dr. Stein. “We found that the volume of several of these structures were predictive of PTSD 3-months post-injury.”

Specifically, smaller volume in brain regions called the cingulate cortex, the superior frontal cortex, and the insula predicted PTSD at 3 months. The regions are associated with arousal, attention and emotional regulation. The structural imaging did not predict PTSD at 6 months.

The findings are in line with previous studies showing smaller volume in several of these brain regions in people with PTSD and studies suggesting that the reduced cortical volume may be a risk factor for developing PTSD. Together, the findings suggest that a “brain reserve,” or higher cortical volumes, may provide some resilience against PTSD.

Although the biomarker of brain volume differences is not yet robust enough to provide clinical guidance, Dr. Stein said, “it does pave the way for future studies to look even more closely at how these brain regions may contribute to (or protect against) mental health problems such as PTSD.”

Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the work, “This very important study uses magnetic resonance imaging to take the field a step closer to understanding why some people develop PTSD after trauma and others do not. It also lays the groundwork for future research aimed at using brain imaging to help predict that a person is at increased risk and may benefit from targeted interventions to reduce the clinical impact of a traumatic event.”

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New research may explain severe virus attacks on the lungs — ScienceDaily


In some cases, immune cells in the lungs can contribute to worsening a virus attack. In a new study, researchers at Karolinska Institutet in Sweden describe how different kinds of immune cells, called macrophages, develop in the lungs and which of them may be behind severe lung diseases. The study, which was published in Immunity, may contribute to future treatments for COVID-19, among other diseases.

The structure of the lungs exposes them to viruses and bacteria from both the air and the blood. Macrophages are immune cells that, among other things, protect the lungs from such attacks. But under certain conditions, lung macrophages can also contribute to severe lung diseases, such as chronic obstructive pulmonary disease (COPD) and COVID-19.

To date, research on the development of human lung macrophages has been limited.

Macrophages can have different origins and develop, among other things, from white blood cells, monocytes, that are divided into different genetically determined main types. In humans, two of these are “classical” CD14+ monocytes and “non-classical” CD16+ monocytes.

In a new study at Karolinska Institutet, researchers have used a model to study the development of lung macrophages directly in a living lung. This has been combined with a method to study gene activity in individual cells, RNA sequencing, and thereby discovered how blood monocytes become human lung macrophages.

“In our study, we show that classical monocytes migrate into airways and lung tissue and are converted into macrophages that protect the health and function of the lungs. We have also identified a special kind of monocyte, HLA-DRhi, which is an intermediate immune cell between a blood monocyte and an airway macrophage. These HLA-DRhi monocytes can leave the blood circulation and migrate into the lung tissue,” says Tim Willinger, Associate Professor at the Department of Medicine, Huddinge, Karolinska Institutet, who led the study.

The non-classical monocytes, however, develop into macrophages in the many blood vessels of the lungs and do not migrate into the lung tissue.

“Certain macrophages in the lungs probably have a connection to a number of severe lung diseases. In respiratory infections, for example, monocytes in the lungs develop into macrophages, which combat viruses and bacteria. But a certain type of macrophage may also contribute to severe inflammation and infections,” says the study’s first author Elza Evren, a doctoral student in Tim Willinger’s research team.

In an infection with the novel coronavirus, SARS-COV-2, which causes COVID-19, researchers believe that protective, anti-inflammatory macrophages are replaced by pro-inflammatory lung macrophages from blood monocytes.

“The existence of these blood monocyte-derived macrophages has been shown in other studies to correlate with how severely ill a person becomes in COVID-19 and how extensive the damage to the lungs is. Patients with severe COVID-19 also have fewer HLA-DRhi monocytes in their blood, probably because they move away from the blood into the lungs. Given their important role in rapid inflammatory responses, our results indicate that future treatments should focus on inflammatory macrophages and monocytes to reduce lung damage and mortality from severe COVID-19,” says Tim Willinger.

The research is financed by the Swedish Research Council, Karolinska Institutet, Centre for Innovative Medicine (CIMED)/Region Stockholm, the Swedish Heart-Lung Foundation, and the Swedish Cancer Foundation. There are no reported conflicts of interest.

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Materials provided by Karolinska Institutet. Note: Content may be edited for style and length.



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