High metabolism is an early sign of Alzheimer’s disease

Illustration Credit: geralt

An early phase in the process of developing Alzheimer’s disease is a metabolic increase in a part of the brain called the hippocampus, report researchers from Karolinska Institutet in a study published in Molecular Psychiatry. The discovery opens up new potential methods of early intervention.

Alzheimer’s disease is the most common form of dementia and strikes about 20,000 people in Sweden every year. Researchers now show that a metabolic increase in the mitochondria, the cellular power plants, is an early indicator of the disease. 

The teams behind the study used mice that developed Alzheimer’s disease pathology in a similar way to humans. The increase in metabolism in young mice was followed by synaptic changes caused by disruption to the cellular recycling system (a process known as autophagy), a finding that was awarded the Nobel Prize in Physiology or Medicine in 2016. 

After a time, metabolism in the Alzheimer brain usually declines, which contributes to the degradation of synapses. This the researchers could also see in the older mice, which had had the disease for a longer time. 

Fossil fuels responsible for heart arrhythmias in mammals

Photo Credit: Pixabay

One of the most common byproducts of the burning of fossil fuels, phenanthrene, causes heart arrhythmias in mice, proving for the first time it is toxic to mammals, new research has discovered.

The study, led by The University of Manchester in collaboration with the University of Bristol and Moscow State University, and funded by the British Heart Foundation, is published today in the journal Environmental Health Perspectives.

Thanks to earlier work by one of the lead authors Professor Holly Shiels from Manchester in conjunction with scientists at the University of Bristol, Moscow State University, National Oceanic and Atmospheric Association (NOAA) and Stanford University, phenanthrene's toxicity to the hearts of fish and crustaceans (crayfish) has been well established.

But now the team has discovered the change also occurs in healthy mouse hearts when directly exposed to phenanthrene, mimicking what happens when we breathe in pollution.

Professor Holly Shiels said: "We've known that phenanthrene is causally linked to cardiotoxicity in fish for many years - scientists recognized this following the disastrous impact of the Exxon Valdez oil disaster in Alaska in 1989.

Ocean warming is accelerating, and hotspots reveal which areas are absorbing the most heat

The Southern Ocean (Antarctic Ocean) saw the largest increase in heat storage over the past two decades.

A new study reveals increasing warming rates in the world’s oceans in recent decades and the locations with the greatest heat uptake.

Ocean warming has accelerated dramatically since the 1990s, nearly doubling during 2010–2020 relative to 1990–2000, according to new UNSW Sydney-led research.

The study, published this week in Nature Communications, also shows some areas of the ocean are doing more of the work in heat uptake or absorption, which has implications for our understanding of sea-level rise and climate impacts.

Increasing concentrations of greenhouse gases in the atmosphere from human activity traps heat within the climate system, warming air, the land surface, the oceans, and melting polar ice. Oceans do by far the most work, absorbing more than 90 per cent of the excess human-generated heat accumulated in the Earth’s climate system, moderating atmospheric temperature rises.

Mobile phone use may affect semen quality

Sample of human spermatozoa used in the study by Serge Nef and Rita Rahban (2023), researcher at the Department of Genetic Medicine and Development of the UNIGE Faculty of Medicine and at the SCAHT - Swiss Centre for Applied Human Toxicology.
Image Credit: Rita Rahban

Does electromagnetic radiation emitted by mobile phones affect semen quality? While various environmental and lifestyle factors have been proposed to explain the decline in semen quality observed over the last fifty years, the role of mobile phones has yet to be demonstrated. A team from the University of Geneva (UNIGE), in collaboration with the Swiss Tropical and Public Health Institute (Swiss TPH), has published a major cross-sectional study on the subject. It shows that frequent use of mobile phones is associated with a lower sperm concentration and total sperm count. However, researchers did not find any association between mobile phone use and low sperm motility and morphology. Read the results in Fertility and Sterility.

Semen quality is determined by the assessment of parameters such as sperm concentration, total sperm count, sperm motility and sperm morphology. According to the values established by the World Health Organization (WHO), a man will most probably take more than one year to conceive a child if his sperm concentration is below 15 million per milliliter. In addition, the percentage chance of pregnancy will decrease if the sperm concentration is below 40 million per milliliter.

Many studies have shown that semen quality has decreased over the last fifty years. The sperm count is reported to have dropped from an average of 99 million sperm per milliliter to 47 million per milliliter. This phenomenon is thought to be the result of a combination of environmental factors (endocrine disruptor, pesticides, radiation) and lifestyle habits (diet, alcohol, stress, smoking).

Amazon deforestation linked to long distance climate warming

Amazon Forest seen from the Amazon Tall Tower Observatory, a scientific research facility in the Amazon rainforest of Brazil. 
Photo Credit Dr Jess Baker, University of Leeds.

Deforestation in the Amazon causes land surfaces up to 100 kilometers away to get warmer, according to a new study.

The research, by a team of British and Brazilian scientists, led by Dr Edward Butt at the University of Leeds, suggests that tropical forests play a critical role in cooling the land surface - and that effect can play out over considerable distances. 

It is known that when tropical forests are cleared, the climate in the immediate vicinity gets warmer.  

In this latest study, the researchers wanted to know if deforestation in the Amazon was resulting in climate warming further afield, and the study examined the impact of forest loss on sites up to 100 kilometers away. 

Researchers Show SARS-Cov-2 Infection Affects Energy Stores in the Body, Causing Organ Failure

Jonathan C. Schisler, PhD
Photo Credit: Courtesy of UNC

An international research team, including Jonathan C. Schisler, PhD, in the UNC School of Medicine, has found how SARS-CoV-2 causes widespread “energy outages” throughout major organs, and how these effects contribute to debilitating long COVID symptoms.

The lungs were once at the forefront of SARS-Cov-2 research, but as reports of organ failure and other serious complications poured in, scientists set out to discover how and why the respiratory virus was causing serious damage to the body’s major organs, including the lungs.

An interdisciplinary COVID-19 International Research Team (COV-IRT), which includes UNC School of Medicine’s Jonathan C. Schisler, PhD, found that SARS-CoV-2 alters mitochondria on a genetic level, leading to widespread “energy outages” throughout the body and its major organs. Their findings, published in Science Translational Medicine, explain how these effects contribute to long COVID symptoms and point to new therapeutic targets.

“We found that at peak infection time, there are distinct changes in different regions of the brain, including is a large decrease in mitochondrial genes in the cerebellum, the part of the brain that controls our muscles, balance, cognition, and emotion” said Schisler, assistant professor of pharmacology and member of the UNC McAllister Heart Institute. “The lung is the primary site of infection, but molecular signals are being transmitted affecting the entire body, with the heart, kidney, and liver being more affected than others, even long after the virus is gone.”

Sets of neurons work in sync to track ‘time’ and ‘place,’ giving humans context for past, present and future

Illustration Credit: MasterTux

Two studies led by UCLA researchers offer new insights into the way neurons in the human brain represent time and space – the most basic ingredients of consciousness of human existence and the primary dimensions of experience that allow us to reconstruct the past and envision the future.

The new findings are based on recordings of the activity of single neurons in the brain, from studies led by Dr. Itzhak Fried, a neurosurgeon and researcher at the UCLA David Geffen School of Medicine, is the senior author of two articles in Cell Reports. Patients who had undergone surgical placement of special depth electrodes developed and implanted by Fried for surgical treatment of intractable epilepsy agreed to perform cognitive tasks while their brain cell activity is recorded for these studies.

Neurons that act as the brain’s GPS system – termed “place cells” and “grid cells” – were discovered initially in rodents, similar findings later described in humans by Fried and colleagues at UCLA in collaboration with Dr. Michael Kahana, professor of Psychology at the University of Pennsylvania and a co-senior author of one of the new studies. The brain’s clock cells, or “time cells,” were identified in more recent years.

New genes linked to ADHD identified potentially paving the way for new treatments

Image Credit: Braňo

Several new genes associated with conditions such as Attention-deficit hyperactivity disorder (ADHD) have been identified, unearthing a significant connection between these disorders and our immune system that could lead to new treatments. The research from the University of Surrey also confirms the role of gene ADGRL3 in conditions such as ADHD, giving scientists a greater understanding of its workings.

During this innovative study, scientists led by Dr Matt Parker from Surrey set out to understand more about ADGRL3, a gene closely linked to ADHD and other ‘externalizing’ disorders, in promoting behaviors such as substance abuse, which can be associated with the conditions. Through this work, scientists identified several new genes related to externalizing disorders, which could lead to the development of new medication to lessen the impact on individuals.

DNA organization influences the growth of deadly brain tumors in response to neuronal signals

Silvia Remeseiro
Photo Credit: Mattias Pettersson

A pioneering study at Umeå University, Sweden, has unveiled that the 3D organization of DNA can influence the progression of the aggressive brain tumor known as glioblastoma. Having identified the factors that glioblastoma uses to respond to neurons by growing and spreading, this discovery paves the way for further research into new treatments for brain tumors.

"We have now identified the most important factors behind how the tumor responds to nerve cells, thus becoming more dangerous. These findings offer hope in our long-term battle against this difficult-to-treat cancer, for which the prognosis has not improved in decades," comments Silvia Remeseiro, Wallenberg fellow at WCMM, Assistant Professor at Umeå University, and lead author of the study.

Glioblastoma is the most fatal type of brain tumor among adults and there is currently no curative treatment. Glioblastoma patients typically face a survival of roughly one-year post-diagnosis. Even following current treatment regimes, which include surgery, radiotherapy and chemotherapy, a mere four per cent of patients are still alive five years after diagnosis.

Pinpointing HIV immune response

HIV, the AIDS virus (yellow), infecting a human cell
Image Credit: National Cancer Institute

New research combining computer modeling and experiments with macaques shows the body’s immune system helps control human immunodeficiency virus (HIV) infections largely by suppressing viral production in already infected cells while also killing viral infected cells, but only within a narrow time window at the start of a cell’s infection.

“To eliminate HIV, we have to understand how the immune system attempts to control the infection,” said Ruy M. Ribeiro, a theoretical biologist at Los Alamos National Laboratory who led the development of the model underpinning the research. Ribeiro is the corresponding author of the paper about the findings, published in Nature Communications.

The research team included Los Alamos Senior Fellow Alan S. Perelson and a former Los Alamos postdoctoral researcher now at the Fred Hutchinson Cancer Research Center. Their collaborators at the University of Pittsburg managed the experiments with macaques infected with simian immunodeficiency virus (SIV) to validate the model. SIV infections in monkeys behave the same way as HIV in humans.