Scientist Study

Vegetarians appear to have a healthier biomarker profile than meat-eaters, and this applies to adults of any age and weight, and is also unaffected by smoking and alcohol consumption, according to a new study in over 166,000 UK adults, being presented at this week's European Congress on Obesity (ECO), held online this year.

Biomarkers can have bad and good health effects, promoting or preventing cancer, cardiovascular and age-related diseases, and other chronic conditions, and have been widely used to assess the effect of diets on health. However, evidence of the metabolic benefits associated with being vegetarian is unclear.

To understand whether dietary choice can make a difference to the levels of disease markers in blood and urine, researchers from the University of Glasgow did a cross-sectional study analysing data from 177,723 healthy participants (aged 37-73 years) in the UK Biobank study, who reported no major changes in diet over the last five years.

Participants were categorised as either vegetarian (do not eat red meat, poultry or fish; 4,111 participants) or meat-eaters (166,516 participants) according to their self-reported diet. The researchers examined the association with 19 blood and urine biomarkers related to diabetes, cardiovascular diseases, cancer, liver, bone and joint health, and kidney function.

Even after accounting for potentially influential factors including age, sex, education, ethnicity, obesity, smoking, and alcohol intake, the analysis found that compared to meat-eaters, vegetarians had significantly lower levels of 13 biomarkers, including: total cholesterol; low-density lipoprotein (LDL) cholesterol—the so-called 'bad cholesterol; apolipoprotein A (linked to cardiovascular disease), apolipoprotein B (linked to cardiovascular disease); gamma-glutamyl transferase (GGT) and alanine aminotransferase (AST)—liver function markers indicating inflammation or damage to cells; insulin-like growth factor (IGF-1; a hormone that encourages the growth and proliferation of cancer cells); urate; total protein; and creatinine (marker of worsening kidney function).

However, vegetarians also had lower levels of beneficial biomarkers including high-density lipoprotein 'good' (HDL) cholesterol, and vitamin D and calcium (linked to bone and joint health). In addition, they had significantly higher level of fats (triglycerides) in the blood and cystatin-C (suggesting a poorer kidney condition).

No link was found for blood sugar levels (HbA1c), systolic blood pressure, aspartate aminotransferase (AST; a marker of damage to liver cells) or C-reactive protein (CRP; inflammatory marker).

"Our findings offer real food for thought", says Dr. Carlos Celis-Morales from the University of Glasgow, UK, who led the research. "As well as not eating red and processed meat which have been linked to heart diseases and some cancers, people who follow a vegetarian diet tend to consume more vegetables, fruits, and nuts which contain more nutrients, fibre, and other potentially beneficial compounds. These nutritional differences may help explain why vegetarians appear to have lower levels of disease biomarkers that can lead to cell damage and chronic disease."

The authors point out that although their study was large, it was observational, so no conclusions can be drawn about direct cause and effect. They also note several limitations including that they only tested biomarker samples once for each participant, and it is possible that biomarkers might fluctuate depending on factors unrelated to diet, such as existing diseases and unmeasured lifestyle factors. They also note that were reliant on participants to report their dietary intake using food frequency questionnaires, which is not always reliable.

This story is based on poster presentation EP3-33 at the European Congress on Obesity (ECO).

In Alzheimer's disease, neurons in the brain die. Largely responsible for the death of neurons are certain protein deposits in the brains of affected individuals: So-called beta-amyloid proteins, which form clumps (plaques) between neurons, and tau proteins, which stick together the inside of neurons. The causes of these deposits are as yet unclear. In addition, a rapidly progressive atrophy, i.e. a shrinking of the brain volume, can be observed in affected persons. Alzheimer's symptoms such as memory loss, disorientation, agitation and challenging behavior are the consequences.

Scientists at the DZNE led by Prof. Michael Wagner, head of a research group at the DZNE and senior psychologist at the memory clinic of the University Hospital Bonn, have now found in a study that a regular Mediterranean-like dietary pattern with relatively more intake of vegetables, legumes, fruit, cereals, fish and monounsaturated fatty acids, such as from olive oil, may protect against protein deposits in the brain and brain atrophy. This diet has a low intake of dairy products, red meat and saturated fatty acids.

A total of 512 subjects with an average age of around seventy years took part in the study. 169 of them were cognitively healthy, while 343 were identified as having a higher risk of developing Alzheimer's disease - due to subjective memory impairment, mild cognitive impairment that is the precursor to dementia, or first-degree relationship with patients diagnosed with Alzheimer's disease. The nutrition study was funded by the Diet-Body-Brain competence cluster of the German Federal Ministry of Education and Research (BMBF) and took place as part of the so-called DELCODE study of the DZNE, which does nationwide research on the early phase of Alzheimer's disease - that period before pronounced symptoms appear.

"People in the second half of life have constant eating habits. We analyzed whether the study participants regularly eat a Mediterranean diet - and whether this might have an impact on brain health ", said Prof. Michael Wagner. The participants first filled out a questionnaire in which they indicated which portions of 148 different foods they had eaten in the past months. Those who frequently ate healthy foods typical of the Mediterranean diet, such as fish, vegetables and fruit, and only occasionally consumed foods such as red meat, scored highly on a scale.

The scientists then investigated brain atrophy: they performed brain scans with magnetic resonance imaging (MRI) scanners to determine brain volume. In addition, all subjects underwent various neuropsychological tests in which cognitive abilities such as memory functions were examined. The research team also looked at biomarker levels (measured values) for amyloid beta proteins and tau proteins in the so-called cerebrospinal fluid (CSF) of 226 subjects.

The researchers, led by Michael Wagner, found that those who ate an unhealthy diet had more pathological levels of these biomarkers in the cerebrospinal fluid than those who regularly ate a Mediterranean-like diet. In the memory tests, the participants who did not adhere to the Mediterranean diet also performed worse than those who regularly ate fish and vegetables. "There was also a significant positive correlation between a closer adherence to a Mediterranean-like diet and a higher volume of the hippocampus. The hippocampus is an area of the brain that is considered the control center of memory. It shrinks early and severely in Alzheimer's disease," explained Tommaso Ballarini, PhD, postdoctoral fellow in Michael Wagner's research group and lead author of the study.

"It is possible that the Mediterranean diet protects the brain from protein deposits and brain atrophy that can cause memory loss and dementia. Our study hints at this," Ballarini said. "But the biological mechanism underlying this will have to be clarified in future studies." As a next step, Ballarini and Wagner now plan to re-examine the same study participants in four to five years to explore how their nutrition - Mediterranean-like or unhealthy - affects brain aging over time.

Ballarini T, Lent DM van, Brunner J, et al. Mediterranean diet, alzheimer disease biomarkers and brain atrophy in old age. Neurology. 2021. doi:  10.1212/WNL.0000000000012067

The powerful laser can be used to examine phenomena believed to be responsible for high-power cosmic rays, which have energies of more than a quadrillion (1015) electronvolts (eV). Although scientists know that these rays originate from somewhere outside our solar system, how they are made and what is forming them has been a longstanding mystery.

"This high intensity laser will allow us to examine astrophysical phenomena such as electron-photon and photon-photon scattering in the lab," said Chang Hee Nam, director of CoReLS and professor at Gwangju Institute of Science & Technology. "We can use it to experimentally test and access theoretical ideas, some of which were first proposed almost a century ago."

In Optica, The Optical Society's (OSA) journal for high impact research, the researchers report the results of years of work to increase the intensity of laser pulses from the CoReLS laser. Studying laser matter-interactions requires a tightly focused laser beam and the researchers were able to focus the laser pulses to a spot size of just over one micron, less than one fiftieth the diameter of a human hair. The new record-breaking laser intensity is comparable to focusing all the light reaching earth from the sun to a spot of 10 microns.

"This high intensity laser will let us tackle new and challenging science, especially strong field quantum electrodynamics, which has been mainly dealt with by theoreticians," said Nam. "In addition to helping us better understand astrophysical phenomena, it could also provide the information necessary to develop new sources for a type of radiation treatment that uses high-energy protons to treat cancer."

The new accomplishment extends previous work in which the researchers demonstrated a femtosecond laser system, based on Ti:Sapphire, that produces 4 petawatt (PW) pulses with durations of less than 20 femtoseconds while focused to a 1 micrometer spot. This laser, which was reported in 2017, produced a power roughly 1,000 times larger than all the electrical power on Earth in a laser pulse that only lasts twenty quadrillionths of a second.

To produce high-intensity laser pulses on target, the generated optical pulses must be focused extremely tightly. In this new work, the researchers apply an adaptive optics system to precisely compensate optical distortions. This system involves deformable mirrors -- which have a controllable reflective surface shape -- to precisely correct distortions in the laser and generate a beam with a very well-controlled wavefront. They then used a large off-axis parabolic mirror to achieve an extremely tight focus. This process requires delicate handling of the focusing optical system.

"Our years of experience gained while developing ultrahigh power lasers allowed us to accomplish the formidable task of focusing the PW laser with the beam size of 28 cm to a micrometer spot to accomplish a laser intensity exceeding 1023 W/cm2," said Nam.

The researchers are using these high-intensity pulses to produce electrons with an energy over 1 GeV (109 eV) and to work in the nonlinear regime in which one electron collides with several hundred laser photons at once. This process is a type of strong field quantum electrodynamics called nonlinear Compton scattering, which is thought to contribute to the generation of extremely energetic cosmic rays.

They will also use the radiation pressure created by the ultrahigh intensity laser to accelerate protons. Understanding how this process occurs could help develop a new laser-based proton source for cancer treatments. Sources used in today's radiation treatments are generated using an accelerator that requires a huge radiation shield. A laser-driven proton source is expected to reduce the system cost, making the proton oncology machine less costly and thus more widely accessible to patients.

The researchers continue to develop new ideas for enhancing the laser intensity even more without significantly increasing the size of the laser system. One way to accomplish this would be to figure out a new way to reduce the laser pulse duration. As lasers with peaks power ranging from 1 to 10 PW are now in operation and several facilities reaching 100 PW are being planned, there is no doubt that high-intensity physics will progress tremendously in the near future.

Jin Woo Yoon, Yeong Gyu Kim, Il Woo Choi, Jae Hee Sung, Hwang Woon Lee, Seong Ku Lee, Chang Hee Nam. Realization of laser intensity over 1023  W/cm2. Optica, 2021; 8 (5): 630 DOI: 10.1364/OPTICA.420520

A comprehensive review into what we know about COVID-19 and the way it functions suggests the virus has a unique infectious profile, which explains why it can be so hard to treat and why some people experience so-called "long COVID," struggling with significant health issues months after infection.

There is growing evidence that the virus infects both the upper and lower respiratory tracts—unlike "low pathogenic" human coronavirus sub-species, which typically settle in the upper respiratory tract and cause cold-like symptoms, or "high pathogenic" viruses such as those that cause SARS and ARDS, which typically settle in the lower respiratory tract.

Additionally, more frequent multi-organ impacts, blood clots, and an unusual immune-inflammatory response not commonly associated with other similar viruses mean that COVID-19 has evolved a uniquely challenging set of characteristics.

While animal and experimental models imply an overly aggressive immune-inflammation response is a key driver, it seems things work differently in humans: Although inflammation is a factor, it is a unique disregulation of the immune response that causes our bodies to mismanage the way they fight the virus.

This may explain why some people experience "long COVID" and suffer severe lung damage after infection.

Ignacio Martin-Loeches, Clinical Professor in Trinity College Dublin's School of Medicine, and Consultant in Intensive Care Medicine at St James's Hospital, is a co-author of the review just published in leading medical journal The Lancet. He said:

"The emergence of severe acute respiratory syndrome coronavirus two (SARS-CoV-2), which causes COVID-19, has resulted in a health crisis not witnessed since the 1918 Spanish flu pandemic. Tragically, millions around the world have died already.

"Despite international focus on the virus, we are only just beginning to understand its intricacies. Based on growing evidence we propose that COVID-19 should be perceived as a new entity with a previously unknown infectious profile. It has its own characteristics and distinct pathophysiology and we need to be aware of this when treating people.

"That doesn't mean we should abandon existing best-practice treatments that are based on our knowledge of other human coronaviruses, but an unbiased, gradual assembly of the key COVID-19 puzzle pieces for different patient cohorts—based on sex, age, ethnicity, pre-existing comorbidities—is what is needed to modify the existing treatment guidelines, subsequently providing the most adequate care to COVID-19 patients."

The review article was produced by the European Group on Immunology of Sepsis (EGIS) in which Professor Martin-Loeches is one of the funding members. EGIS is a multidisciplinary group of scientists and doctors with special interest in severe infection in patients admitted to ICU.

Marcin F Osuchowski et al, The COVID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity, The Lancet Respiratory Medicine (2021). DOI: 10.1016/S2213-2600(21)00218-6

The hunt for life on Mars continues, with NASA’s latest rover Perseverance using its scientific instrumentation to scan the Jezero Crater, an area believed to be a dried up ancient lake, for any signs of ancient microbial life.

But according to an international team of researchers, the space agencies other rovers may have already found signs of relatively advanced life — in the form of “fungus-like Martian specimens,” according to a new paper published in the journal Advances in Microbiology.

The team, which includes researchers from the Harvard-Smithsonian Center for Astrophysics and George Mason University, believes they have found photographic evidence of a variety of fungus-like organisms, some resembling the shape of puffballs, a round cloud-like fungus found in abundance back here on Earth, on the Red Planet.

Their evidence: images taken by NASA’s Opportunity and Curiosity rovers as well as the agency’s HiRISE high-resolution camera attached to the Mars Reconnaissance Orbiter.

“Fungi thrive in radiation intense environments,” the team writes in its paper. “Sequential photos document that fungus-like Martian specimens emerge from the soil and increase in size, including those resembling puffballs.”

“After obliteration of spherical specimens by the rover wheels, new sphericals — some with stalks — appeared atop the crests of old tracks,” the researchers write.

The team went so far as to say that “black fungi-bacteria-like specimens also appeared atop the rovers.”

They didn’t stop there: the team also examined photos taken by NASA’s HiRISE, and found evidence for “amorphous specimens within a crevice” that “changed shape and location then disappeared.”

“It is well established that a variety of terrestrial organisms survive Mars-like conditions,” the team concludes. “Given the likelihood Earth has been seeding Mars with life and life has been repeatedly transferred between worlds, it would be surprising if there was no life on Mars.”

The team argues that these Martian lifeforms “would have evolved on and already be adapted to the low temperatures, intermittent availability of water, low amounts of free oxygen, and high levels of radiation.”

The researchers did caveat their findings, pointing out that “similarities in morphology are not proof of life,” and that “we cannot completely rule out minerals, weathering, and unknown geological forces that are unique to Mars and unknown and alien to Earth.”

But it’s  a wild conclusion nonetheless. The researchers’ peers will likely go over the paper with a fine-toothed comb, and likely shred the results — it’s not every day that researchers are willing to stick out their necks and claim to have found evidence of life on Mars.

Carnegie Mellon University's He Lab is focusing on noninvasive neuroengineering solutions that not only provide diagnostic techniques, but also innovative treatment options. Their latest research has demonstrated that noninvasive neuromodulation via low-intensity ultrasound can have cell-type selectivity in manipulating neurons.

Parkinson's Disease, epilepsy and insomnia are just a few of the neurological disorders that use neuromodulation treatment techniques today. Neuromodulation delivers controlled physical energy to the nervous system to treat and improve patients' quality of life. Current neuromodulation approaches, while effective, bring both drawbacks and limitations.

"Deep brain stimulation, which is highly successful, but an invasive form of electric stimulation through implanted electrodes, is one example of how neuromodulation is being used in a clinical setting today," explained Bin He, professor of biomedical engineering at Carnegie Mellon University. "Medical professionals have also used noninvasive transcranial magnetic stimulation and transcranial current stimulation, both of which lack the ability to specifically focus on the neuro-circuit level. My group is interested in helping to develop a more effective and completely noninvasive alternative."

Low-intensity transcranial focused ultrasound, or tFUS, is an emerging and fully reversable neuromodulation technology. It is noninvasive, precise, and it does not require surgery. During tFUS neuromodulation, pulsed mechanical energy is transmitted through the skull, with high spatial resolution and selectivity, at highly-targeted brain regions, which can be steered to elicit activation or inhibition through parameter tuning.

In work recently published in Nature Communications, He's group demonstrated, for the first time, that specific cell types can be targeted through tFUS neuromodulation. Their study found that excitatory neurons showed high sensitivity to ultrasound pulse repetition frequency, while inhibitory neurons did not.

This finding is significant, because it demonstrates the first capability for a noninvasive neuromodulation technique to modulate a selected cell subpopulation, using a technique that can be directly translated for human use. With the demonstrated capability of tFUS to activate excitatory or inhibitory neurons, future applications may lead to precise targeting of brain circuits using focused ultrasound energy, and activate or inhibit selected sub-populations of neurons by tuning ultrasound parameters.

"As a result of our research, we obtained direct evidence that different neuron populations unequally respond to ultrasound stimulation in the brain," said Kai Yu, co-first author of the paper and a research scientist in He's lab at Carnegie Mellon University. "We identified a critical stimulation parameter that is able to tune the balance between excitatory and inhibitory neuronal activities, and we conducted thorough control experiments to support these valuable neuroscience findings."

The application of this research has broad implications; it's not just limited to one disease. For many people suffering from pain, depression and addition, He believes non-invasive tFUS neuromodulation could be used to facilitate treatment.

"If we can localize and target areas of the brain using acoustic, ultrasound energy, I believe we can potentially treat a myriad of neurological and psychiatric diseases and conditions," said He. "This type of treatment option has great potential to shift what doctors study in medical school and go on to practice. Of course, a noninvasive, precise, reversive treatment option also presents endless benefits for patients. My dream would be to make everything noninvasive."

He's next goal is to further develop the tFUS neuromodulation technology with increased spatial resolution and focality, and directly test the applicability of tFUS to treat brain conditions in humans.

Yu K, Niu X, Krook-Magnuson E, He B. Intrinsic functional neuron-type selectivity of transcranial focused ultrasound neuromodulation. Nat Commun. 2021;12(1):2519. doi: 10.1038/s41467-021-22743-7

You already know that your fingers let you feel the slightest change in surface and temperature, but what about differentiating identical materials on the surface? How much can our sense of touch surprise us? Charles Dhong of the University of Delaware and his colleagues investigated whether it was possible to sense a chemical difference in which the internal molecular structures of two materials vary slightly, without their surfaces differing. To do this, they carried out tests with combinations of materials/compounds whose surface was designed to be identical to the touch. The results were published in the journal Soft Matter. 

The researchers chose a silicon wafer as a base and attached to it a layer of a simple compound, only one molecule thick. They tested several compounds, all slightly different from each other. Out of six pairs of compounds, testers (humans) were able to distinguish three. In the case of a pair, where the team replaced only a single carbon atom with a nitrogen atom, the testers were able to distinguish the two pairs with an accuracy of 68%.

Sense of touch: sub-nanometric precision

“When we make our samples, physically they are almost identical, the differences are on a sub-nanoscale,” Dhong explains. "But when test subjects smelled them, some said some felt a little grainy and others were more pleasant and velvety."

The chemical difference between the two compounds that the testers were best able to distinguish was a slight change in the degree of friction they felt when running a finger over them. This alteration was not due to differences in surface area, but rather to the way their molecules fit together.

According to Dhong, these results could be useful for creating realistic feel textures in virtual reality environments. "If you want to create a texture that gives the impression of passing your hand over a beautiful paper, a soft velvet or a wooden table, how do you do it with a screen? It gives us a lot more options to really expand that toolbox,” Dhong explains.