A link between childhood stress and early molars
June 9, 2021
Science Daily/University of Pennsylvania
Early in her career neuroscientist Allyson Mackey began thinking about molars. As a researcher who studies brain development, she wanted to know whether when these teeth arrived might indicate early maturation in children.
"I've long been concerned that if kids grow up too fast, their brains will mature too fast and will lose plasticity at an earlier age. Then they'll go into school and have trouble learning at the same rate as their peers," says Mackey, an assistant professor in the Department of Psychology at Penn. "Of course, not every kid who experiences stress or [is] low income will show this pattern of accelerated development."
What would help, she thought, was a scalable, objective way -- a physical manifestation, of sorts -- to indicate how children embodied and responded to stresses in their world. Eruption timing of the first permanent molars proved to be just that.
In the Proceedings of the National Academy of Sciences, Mackey, with doctoral student Cassidy McDermott and colleagues from Penn's School of Dental Medicine and the University of Missouri-Kansas City, shows that children from lower-income backgrounds and those who go through greater adverse childhood experiences get their first permanent molars earlier. The findings, generated initially from a small study and replicated using a nationally representative dataset, align with a broader pattern of accelerated development often seen under conditions of early-life stress.
"It's really important for us to understand how to detect early maturation sooner," Mackey says. "Right now, we're relying on seeing when kids hit puberty, which might be too late for some meaningful interventions. If we can inexpensively see that a child is experiencing this maturation earlier, we might be able to direct more intervention resources toward them."
A novel rating system
Broadly speaking, Mackey's lab studies how the brain changes and grows as people learn. It's well-established that stress during childhood speeds up maturation and that children who hit puberty earlier are at greater risk for both physical and mental health problems in adulthood.
Beyond that, in studies across primate species, molar eruption has been used to measure childhood length and correlates with a number of other developmental events. Similarly, for humans, the timing of dental events often plays a role in estimating biological age.
"That all made molar eruption a compelling developmental indicator," says McDermott, who is training to be a clinical psychologist.
It helped that more than 100 children, ages 4 to 7, had been participating in two Penn brain development studies, which included structural and functional MRI scans. "There's one type of MRI scan called a T2 weighted scan where you can visualize the morphology of the tooth pretty well," McDermott says. These scans -- typically used to look at the brain -- showed the researchers just how close these molars were to breaking through the gum line.
Once Mackey and McDermott realized this, they partnered with Katherine Hilton, then a student in Penn Dental Medicine, and Muralidhar Mupparapu, a professor in the Department of Oral Medicine, who developed a novel scale to precisely rate each tooth's position.
"The scale ranges from 1 to 4," McDermott says. "At the low end of the scale is 1, which is before the tooth has really developed at all. As the tooth emerges, there are intermediate stages, and the highest rating, a 4, is when the tooth is fully in the mouth and parallel with the other teeth." Four molars each received a score, which then got averaged, leaving a single score per individual.
Controlling for factors like age and gender, the researchers then looked for associations between early environment and molar eruption. "What we found is that income and adverse childhood experiences are both individually associated with molar eruptions status," McDermott says.
Replicating the findings
Those findings derived from just 117 participants, so although the correlation was clear, Mackey and McDermott hoped to replicate what they'd seen.
Collaborators at the University of Missouri-Kansas City told them about a large population-representative dataset called the National Health and Nutrition Examination Survey (NHANES), which is publicly available and includes dental data, demographic data, and family income, among other measures.
"Because our sample is only from one city and is much smaller than a population-representative study like that," McDermott says, "we saw it as an opportunity to verify that the findings exist outside of what we had collected in Philadelphia."
Though some facets differed -- NHANES measures dental development a little differently, for example -- the models showed similar results, indicating a connection between lower family income and earlier first molars.
Whether this overall trend is new or just now coming to light is something Mackey wants to study further. She's also curious about when the rate of maturation gets set. "Is it as early as in utero or is it dynamically adjusted based on stressors in the world?" she says. "If it's the latter, that tells you there are more opportunities to intervene."
Present implications, future work
There are still significant unknowns, as well as findings that need further examination, Mackey says. For example, the research team found racial disparities in this timing, with first molars emerging in Black children sooner than in white children.
"These race differences in molar eruption have been known for a long time, but no one thought critically about where they came from," she says. "It's consistent with higher levels of stress due to structural racism. This is a clear indication that it's not just speculation that experiences with racism can cause stress and early aging. They are having an effect on kids that we can't ignore."
For all children, a year-plus of pandemic-driven grief and social isolation most certainly amplified stress levels, making it even more important to understand who is at greatest risk for early maturation, Mackey says.
Yet she and McDermott emphasize that molar timing shouldn't become another parental fear. "What I really don't want is for parents to either worry or feel complacent just based on when their kids got their molars," says Mackey. "We don't have those data yet."
The Penn researchers are working on it. In the future, they hope to collaborate with dental offices to recruit children into studies based on their molar-eruption status. The goal would be to follow them into adulthood, to get more information on what precisely early first molars may indicate. "If this is the meaningful discovery that I think it is," Mackey says, "I would love for many scientists to jump on board and test these hypotheses."
https://www.sciencedaily.com/releases/2021/06/210609123414.htm
Sugar overload may be a recipe for long-term problems
A new study on the impact of sugar supports World Health Organization recommendations
June 8, 2021
Science Daily/Queensland University of Technology
Children who consume too much sugar could be at greater risk of becoming obese, hyperactive, and cognitively impaired, as adults, according to the results of a new study of mice led by QUT and published by Frontiers in Neuroscience.
The study resulted in a reduced risk of sugar-induced weight gain and other health problems when the mice were given a much smaller daily dose of sucrose, supporting World Health Organisation calls for a reduction in sugar intake by humans.
One of the lead authors, QUT neuroscientist Professor Selena Bartlett, says many children, adolescents, and adults in more than 60 countries, including Australia, have a diet consisting of more than four times the sugar (100g) recommended by the World Health Organisation (25g per person per day).
"More work needs to be done in the investigation of the long-term effects of sugar on adolescents and adults but our results with the mouse model are very promising," said Professor Bartlett.
"Recent evidence shows obesity and impulsive behaviours caused by poor dietary habits leads to further overconsumption of processed food and beverages but the long-term effects on cognitive processes and hyperactivity from sugar overconsumption, beginning at adolescence, are not known," said Professor Bartlett.
"Our study found long-term sugar consumption (a 12-week period with the mice which started the trial at five weeks of age) at a level that significantly boosts weight gain, elicits an abnormal and excessive stimulation of the nervous system in response to novelty. It also alters both episodic and spatial memory. These results are like those reported in attention deficit and hyperactivity disorders.
"Human trials would need to be done but it suggests a link to the long-term overconsumption of sugar, beginning at a young age, which occurs more commonly in the Western Diet and an increased risk of developing persistent hyperactivity and neurocognitive deficits in adulthood."
Professor Bartlett said while the concept of 'sugar addiction' and the classification of sugar as a substance of abuse were still being debated, there is increasing evidence of overlap in the brain circuitry and molecular signalling pathways involved in sugar consumption and drug abuse.
"People consume sugar and food to regulate energy balance, but also for pleasure and comfort. This hedonistic desire for palatable food is reward-driven and overeating can impact upon and even override our ability to regulate," Professor Bartlett said.
"It is increasingly considered that unrestricted consumption of high-sugar food and beverages within the Western Diet might be linked to the increased obesity epidemic. A strong association between attention-deficits/hyperactivity disorders and being overweight or obese have also been revealed.
"Taken together, these data suggest that sugar-induced obesity may participate to the developing pathogenesis of ADHD-like symptoms in western countries. In children, high sugar consumption correlates with hyperactivity and in adults, with inattention and impulsivity.
"What has been unclear though, is whether chronic overconsumption of sucrose -- starting from childhood -- would have the same negative impact on our nervous system, emotions or cognition throughout adulthood as other addictive drugs.
"This study on mice goes a long way to resolving that question. Our results show for the first time that long-term consumption of sucrose leads to significant weight gain and produces persistent hyperactivity and learning impairments."
Co-lead author Dr Arnauld Belmer added that while the overall sugar consumption has dropped since the mid-1990s, obesity rates have climbed.
"This rise in obesity rates could result from a delayed effect of excess sugar, suggesting that adult obesity may be driven by high sugar intake over a life span," Dr Belmer said.
"Interestingly, our investigation with the mice found reducing the daily sucrose intake four-fold did prevent sugar-induced increase in weight gain, supporting the WHO's recommendation to restrict sugar intake by this amount would be effective. It could also limit the other negative consequences including hyperactivity and cognitive impairment."
https://www.sciencedaily.com/releases/2021/06/210608092239.htm
Lack of math education negatively affects adolescent brain and cognitive development
A new study suggests that not having any math education after the age of 16 can be disadvantageous
June 7, 2021
Science Daily/University of Oxford
Adolescents who stopped studying maths exhibited greater disadvantage -- compared with peers who continued studying maths -- in terms of brain and cognitive development, according to a new study published in the Proceedings of the National Academy of Sciences.
133 students between the ages of 14-18 took part in an experiment run by researchers from the Department of Experimental Psychology at the University of Oxford. Unlike the majority of countries worldwide, in the UK 16-year-old students can decide to stop their maths education. This situation allowed the team to examine whether this specific lack of maths education in students coming from a similar environment could impact brain development and cognition.
The study found that students who didn't study maths had a lower amount of a crucial chemical for brain plasticity (gamma-Aminobutyric acid) in a key brain region involved in many important cognitive functions, including reasoning, problem solving, maths, memory and learning. Based on the amount of brain chemical found in each student, researchers were able to discriminate between adolescents who studied or did not study maths, independent of their cognitive abilities. Moreover, the amount of this brain chemical successfully predicted changes in mathematical attainment score around 19 months later. Notably, the researchers did not find differences in the brain chemical before the adolescents stopped studying maths.
Roi Cohen Kadosh, Professor of Cognitive Neuroscience at the University of Oxford, led the study. He said: "Maths skills are associated with a range of benefits, including employment, socioeconomic status, and mental and physical health. Adolescence is an important period in life that is associated with important brain and cognitive changes. Sadly, the opportunity to stop studying maths at this age seems to lead to a gap between adolescents who stop their maths education compared to those who continue it. Our study provides a new level of biological understanding of the impact of education on the developing brain and the mutual effect between biology and education.
"It is not yet known how this disparity, or its long-term implications, can be prevented. Not every adolescent enjoys maths so we need to investigate possible alternatives, such as training in logic and reasoning that engage the same brain area as maths."
Professor Cohen Kadosh added, "While we started this line of research before COVID-19, I also wonder how the reduced access to education in general, and maths in particular (or lack of it due to the pandemic) impacts the brain and cognitive development of children and adolescents. While we are still unaware of the long-term influence of this interruption, our study provides an important understanding of how a lack of a single component in education, maths, can impact brain and behaviour."
https://www.sciencedaily.com/releases/2021/06/210607161149.htm
Attentive listening helps teens open up
June 4, 2021
Science Daily/University of Reading
Engaged listening techniques such as eye contact, nodding and using key words to praise openness helps teenagers when they admit bad behaviour and share hurt feelings with their parents, a new study has shown.
University of Reading and Haifa researchers asked 1001 13 to 16-year-olds to watch a staged conversation between a parent and teenager about a difficult situation, with the parent adopting different body language and listening behaviour in different versions.
The participants who watched the versions where the parent was visibly attentive stated that they would have felt better about themselves as the teenager and would be more likely to open up about their feelings again in the future.
The study, the first to look at quality of listening in isolation from other parenting techniques, revealed that being more engaged while listening made the teenagers feel more authentic and connected with the parent.
Dr Netta Weinstein, associate professor in clinical and social psychology at the University of Reading, who co-led the study, said:
"We all know that listening to someone talk about their problems is an effective way of reassuring them and establishing a connection. However, until now there has been little thought given to the quality of that listening, and the difference that makes."
"This study shows that in parent-teenager relationships, quietly listening to a teenager while showing them they are valued and appreciated for their honesty has a powerful effect on their willingness to open up."
For the study published in the Journal of Experimental Child Psychology, a roughly even split of male and female adolescents were recruited, with three identifying as another gender. The team found that active listening was equally important across all participants.
The first video conversation scenario portrayed a teenage boy admitting to his mother that he had tried vaping and felt ashamed, and in the second he tells his mother he was rejected by his peers after refusing to vape and felt hurt.
Each video scenario had a version where the parent listened attentively, and another where they appeared more distracted, and used less eye contact.
Dr Weinstein said:
"With such a large group of participants, it is reassuring to see that active listening was universally beneficial across these years of adolescence."
"The study has some important implications for teenage wellbeing as well. The participants said that the good listening model observed in the videos would lead to better wellbeing. Although we don't know how often the expectations meets reality, but it's clear that active listening is more likely to lead to a good outcome for teenagers than the more passive style we tested it against."
https://www.sciencedaily.com/releases/2021/06/210604122722.htm
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Laughing gas relieves symptoms in people with treatment-resistant depression
Single treatment provides patients with rapid, lasting antidepressant effects
June 9, 2021
Science Daily/Washington University School of Medicine
A single, one-hour treatment that involves breathing in a mixture of oxygen and nitrous oxide -- otherwise known as laughing gas -- significantly improved symptoms in people with treatment-resistant depression, according to new data from researchers at Washington University School of Medicine in St. Louis and the University of Chicago.
In a phase 2 clinical trial, the researchers demonstrated that symptoms of depression improve rapidly following treatment with inhaled nitrous oxide. Further, they reported the benefits can last for several weeks.
The findings are published June 9 in the journal Science Translational Medicine.
"A large percentage of patients don't respond to standard antidepressant therapies -- the patients in this study had failed an average of 4.5 antidepressant trials -- and it's very important to find therapies to help these patients," said Charles R. Conway, MD, a professor of psychiatry at Washington University and one of the study's senior investigators. "That we saw rapid improvements in many such patients in the study suggests nitrous oxide may help people with really severe, resistant depression."
Conway, and the study's other co-senior investigator, Peter Nagele, MD, professor and chair of the Department of Anesthesia & Critical Care at the University of Chicago, and who previously had an appointment in the Department of Anesthesiology at Washington University School of Medicine, have been studying the potential of nitrous oxide as an antidepressant for the past decade.
Standard antidepressant drugs affect norepinephrine and serotonin receptors in the brain, yet they often take weeks to improve a person's symptoms. Nitrous oxide, however, interacts with different receptors on brain cells -- NMDA glutamate receptors -- and tends to improve symptoms within hours when effective.
"Our primary goals in this study were twofold: to determine whether a lower dose of nitrous oxide might be just as effective as doses we'd tested previously -- and it was for most patients -- and we also wanted to see how long the relief lasted," Nagele said. "In a proof-of-concept study several years ago, we assessed patients for 24 hours. In this study, we continued to assess them for two weeks, and most continued to feel better."
The study involved 24 patients. Each one received three treatments about one month apart. In one session, patients breathed gas for an hour that was half nitrous oxide, half oxygen. In a second treatment, the same patients breathed a solution that was 25% nitrous oxide. A third treatment, the placebo, involved breathing only oxygen, with no nitrous oxide.
"You can't really get a better comparison group than when you compare a person to himself or herself," Nagele said. "Serving as your own control is ideal. The alternative is studying the effects of a drug in two similar groups of people in which you either get one treatment or another. But the problem with that is that you need much larger numbers of patients before you really can draw conclusions."
The primary conclusions in this study were that nitrous oxide -- both at 25% and in a 50-50 mixture with oxygen -- improved depression in 17 of those study participants. The differences between a 25% mix and a 50% mix mainly involved how long the antidepressant effects lasted. Whereas the 50% dosage had greater antidepressant effects two weeks after treatment, the 25% dose was associated with fewer adverse events, the most common of which was feeling nauseated.
"Some patients experience side effects -- it's a small subset, but it's very real -- and the main one is that some people get nauseated," Conway said. "But in our study, only when people got the 50% dose did they experience nausea. When they received 25% nitrous oxide, no one developed nausea. And that lower dose was just about as effective as the higher dose at relieving depression."
Of the 20 people who completed all of the study's treatments and follow-up exams, 55% (11 of 20) experienced a significant improvement in at least half of their depressive symptoms, and 40% (eight of 20) were considered to be in remission -- meaning they no longer were clinically depressed -- after breathing a nitrous oxide solution for one hour.
Over the course of the entire study, having received both dose levels of nitrous oxide and the placebo treatment, some 85% (17 of 20) of the study participants experienced a significant enough improvement that their clinical classification moved at least one category -- for example, from severe to moderate depression.
Many of those in the study also took antidepressant drugs -- medications that, for the most part, had failed to relieve their depression -- but they were allowed to continue using those drugs while they participated in the study.
As many as one-third of those who take antidepressants don't improve. Nitrous oxide and ketamine, another anesthetic drug that interacts with NMDA glutamate receptors, recently have shown promise in those with treatment-resistant depression. Conway and Nagele believe both drugs may represent breakthroughs for people with treatment-resistant depression, but they believe nitrous oxide may have some practical advantages.
"One potential advantage to nitrous oxide, compared with ketamine, is that because it's a volatile gas, its anesthetic effects subside very quickly," Conway said. "It's similar to what happens in a dentist's office when people drive themselves home after getting a tooth pulled. After treatment with ketamine, patients need to be observed for two hours following treatment to make sure they are OK, and then they have to get someone else to drive them."
Nagele and Conway said it is important for scientists soon to conduct a large, multicenter study comparing the effects of ketamine and nitrous oxide to placebo.
This work was supported by a NARSAD award from the Brain & Behavior Research Foundation and the Taylor Family Institute for Innovative Psychiatric Research at Washington University School of Medicine.
https://www.sciencedaily.com/releases/2021/06/210609143446.htm
Having trouble falling asleep predicts cognitive impairment in later life
Study identifies an insomnia symptom that could be an intervention target for dementia prevention
June 9, 2021
Science Daily/American Academy of Sleep Medicine
A study of nearly 2,500 adults found that having trouble falling asleep, as compared to other patterns of insomnia, was the main insomnia symptom that predicted cognitive impairment 14 years later.
Results show that having trouble falling asleep in 2002 was associated with cognitive impairment in 2016. Specifically, more frequent trouble falling asleep predicted poorer episodic memory, executive function, language, processing speed, and visuospatial performance. Further analysis found that associations between sleep initiation and later cognition were partially explained by both depressive symptoms and vascular diseases in 2014 for all domains except episodic memory, which was only partially explained by depressive symptoms.
"While there is growing evidence for a link between insomnia and cognitive impairment in older adults, it has been difficult to interpret the nature of these associations given how differently both insomnia and cognitive impairment can present across individuals," said lead author Afsara Zaheed, a graduate student in clinical science within the department of psychology at the University of Michigan. "By investigating associations between specific insomnia complaints and cognition over time using strong measures of cognitive ability, we hoped to gain additional clarity on whether and how these different sleep problems may lead to poor cognitive outcomes."
Insomnia involves difficulty falling asleep or staying asleep, or regularly waking up earlier than desired, despite allowing enough time in bed for sleep. Daytime symptoms include fatigue or sleepiness; feeling dissatisfied with sleep; having trouble concentrating; feeling depressed, anxious, or irritable; and having low motivation or energy.
The study analyzed data from the Health and Retirement Study, which involved 2,496 adults who were at least 51 years of age. In 2002 they reported the frequency of experiencing insomnia symptoms. In 2016 the participants' cognition was assessed as part of the Harmonized Cognitive Assessment Protocol and operationalized with a comprehensive neuropsychological battery tapping episodic memory, executive function, language, visuoconstruction, and processing speed. Analyses controlled for sociodemographics and baseline global cognitive performance.
"These results are important given the lack of currently available treatments for late-life cognitive disorders, like Alzheimer's disease and other dementias," said Zaheed. "Sleep health and sleep behaviors are often modifiable. These results suggest that regular screening for insomnia symptoms may help with tracking and identifying people with trouble falling asleep in mid-to-late life who might be at risk for developing cognitive impairments later in life. Additional intervention research is needed to determine whether intervening on insomnia symptoms can help prevent or slow the progression of cognitive impairments in later life."
https://www.sciencedaily.com/releases/2021/06/210609143440.htm
Study shows adaptive brain response to stress, and its absence in people with depression
A biological signal for resilience to stress
June 9, 2021
Science Daily/Emory Health Sciences
A new study identifies a novel biomarker indicating resilience to chronic stress. This biomarker is largely absent in people suffering from major depressive disorder, and this absence is further associated with pessimism in daily life, the study finds.
Nature Communications published the research by scientists at Emory University.
The researchers used brain imaging to identify differences in the neurotransmitter glutamate within the medial prefrontal cortex before and after study participants underwent stressful tasks. They then followed the participants for four weeks, using a survey protocol to regularly assess how participants rated their expected and experienced outcomes for daily activities.
"To our knowledge, this is the first work to show that glutamate in the human medial prefrontal cortex shows an adaptive habituation to a new stressful experience if someone has recently experienced a lot of stress," says Michael Treadway, senior author of the study and professor in Emory's Department of Psychology and Department of Psychiatry and Behavioral Science. "Importantly, this habituation is significantly altered in patients with depression. We believe this may be one of the first biological signals of its kind to be identified in relation to stress and people who are clinically depressed."
"Learning more about how acute stress and chronic stress affect the brain may help in the identification of treatment targets for depression," adds Jessica Cooper, first author of the study and a post-doctoral fellow in Treadway's Translational Research in Affective Disorders Laboratory.
The lab focuses on understanding the molecular and circuit-level mechanisms of psychiatric symptoms related to mood disorders, anxiety and decision-making.
It's long been known that stress is a major risk factor for depression, one of the most common and debilitating of mental illnesses. "In many ways, depression is a stress-linked disorder," Treadway says. "It's estimated that 80 percent of first-time depressive episodes are preceded by significant, chronic life stress."
Around 16 to 20 percent of the U.S. population will meet the criteria for a major depressive disorder during their lifetimes. Experts are predicting rates of depression to climb even further in the wake of the ongoing COVID-19 pandemic. During the pandemic, about four in 10 adults in the United States have reported symptoms of anxiety or depressive disorder, up from one in 10 who reported them in 2019, according to the Kaiser Family Foundation.
"The pandemic has created more isolation for many people, while also increasing the amount of severe stressors and existential threats they experience," Treadway says. "That combination puts a lot of people at high risk for becoming depressed."
Although the link between stress and depression is clearly established, the mechanisms underlying this relationship are not. Experiments with rodents have shown an association between the response of glutamate -- the major excitatory neurotransmitter in the mammalian brain -- and stress. The role of glutamate in humans with depression, however, has been less clear.
The 88 participants in the current study included people without a mental health disorder and unmedicated patients diagnosed with a major depressive disorder. Participants were surveyed about perceived recent stress in their lives before they underwent experiments using a brain scanning technique known as magnetic resonance spectroscopy.
While in the scanner, participants were required to alternate between performing two tasks that served as acute stressors: Putting their hand up to the wrist in ice water and counting down from the number 2,043 by steps of 17 while someone evaluated their accuracy.
Brain scans before and after the acute stressor measured glutamate in the medial prefrontal cortex, an area of the brain involved with thinking about one's state and forming expectations. Previous research has also found that this brain area is involved in regulating adaptive responses to stress.
Participants submitted saliva samples while in the scanner, allowing the researchers to confirm that the tasks elicited a stress response by measuring the amount of the stress hormone cortisol in the sample.
In healthy individuals, the brain scans revealed that glutamate change in response to stress in the medial prefrontal cortex was predicted by individual levels of recent perceived stress. Healthy participants with lower levels of stress showed increased glutamate in response to acute stress, while healthy participants with higher levels of stress showed a reduced glutamate response to acute stress. This adaptive response was comparatively absent in the patients diagnosed with depression.
"The decrease in the glutamate response over time appears to be a signal, or a marker, of a healthy adaptation to stress," Treadway says. "And if the levels remain high that appears to be a signal for maladaptive responses to stress."
The initial result was strong for the adaptation in healthy participants, but was in a modest sample size, so the researchers decided to see if they could replicate it. "Not only did we get a replication, it was an unusually strong replication," Treadway says.
The experiment also included a group of healthy controls who underwent scanning before and after performing tasks. Rather than stressful tasks, however, the controls were asked to place a hand into warm water or to simply count out loud consecutively. Their glutamate levels were not associated with perceived stress and they did not show a salivary cortisol response.
To expand their findings, the researchers followed participants for four weeks after scanning. Every other day, the participants reported on their expected and experienced outcomes for activities in their daily lives. The results showed that glutamate changes that were higher than expected based on an individual's level of perceived stress predicted an increased pessimistic outlook -- a hallmark for depression.
"We were able to show how a neural response to stress is meaningfully related to what people experience in their daily lives," Cooper says. "We now have a large, rich data set that gives us a tangible lead to build upon as we further investigate how stress contributes to depression."
The work was supported by the National Institutes of Mental Health.
https://www.sciencedaily.com/releases/2021/06/210609123422.htm
Brain connections mean some people lack visual imagery
June 9, 2021
Science Daily/University of Exeter
New research has revealed that people with the ability to visualise vividly have a stronger connection between their visual network and the regions of the brain linked to decision-making. The study also sheds light on memory and personality differences between those with strong visual imagery and those who cannot hold a picture in their mind's eye.
The research, from the University of Exeter, published in Cerebral Cortex Communications, casts new light on why an estimated one-three per cent of the population lack the ability to visualise. This phenomenon was named "aphantasia" by the University of Exeter's Professor Adam Zeman in 2015 Professor Zeman called those with highly developed visual imagery skills "hyperphantasics."
Funded by the Arts and Humanities Research Council, the study is the first systematic neuropsychological and brain imaging study of people with aphantasia and hypephantasia. The team conducted fMRI scans on 24 people with aphantasia, 25 with hyperphantasia and a control group of 20 people with mid-range imagery vividness. They combined the imaging data with detailed cognitive and personality tests.
The scans revealed that people with hyperphantasia have a stronger connection between the visual network which processes what we see, and which becomes active during visual imagery, and the prefrontal cortices, involved in decision-making and attention. These stronger connections were apparent in scans performed during rest, while participants were relaxing -- and possibly mind-wandering.
Despite equivalent scores on standard memory tests, Professor Zeman and the team found that people with hyperphantasia produce richer descriptions of imagined scenarios than controls, who in turn outperformed aphantasics. This also applied to autobiographical memory, or the ability to remember events that have taken place in the person's life. Aphantasics also had lower ability to recognise faces.
Personality tests revealed that aphantasics tended to be more introverted and hyperphantasics more open.
Professor Zeman said: "Our research indicates for the first time that a weaker connection between the parts of the brain responsible for vision and frontal regions involved in decision-making and attention leads to aphantasia. However, this shouldn't be viewed as a disadvantage -- it's a different way of experiencing the world. Many aphantasics are extremely high-achieving, and we're now keen to explore whether the personality and memory differences we observed indicate contrasting ways of processing information, linked to visual imagery ability."
https://www.sciencedaily.com/releases/2021/06/210609115555.htm
Study finds novel evidence that dreams reflect multiple memories, anticipate future events
Dreams focused on future events utilize memories of multiple past experiences
June 8, 2021
Science Daily/American Academy of Sleep Medicine
Dreams result from a process that often combines fragments of multiple life experiences and anticipates future events, according to novel evidence from a new study.
Results show that 53.5% of dreams were traced to a memory, and nearly 50% of reports with a memory source were connected to multiple past experiences. The study also found that 25.7% of dreams were related to specific impending events, and 37.4% of dreams with a future event source were additionally related to one or more specific memories of past experiences. Future-oriented dreams became proportionally more common later in the night.
"Humans have struggled to understand the meaning of dreams for millennia," said principal investigator Erin Wamsley, who has a doctorate in cognitive neuroscience and is an associate professor in the department of psychology and program in neuroscience at Furman University in Greenville, South Carolina. "We present new evidence that dreams reflect a memory-processing function. Although it has long been known that dreams incorporate fragments of past experience, our data suggest that dreams also anticipate probable future events."
The study involved 48 students who spent the night in the laboratory for overnight sleep evaluation using polysomnography. During the night, participants were awakened up to 13 times to report on their experiences during sleep onset, REM sleep, and non-REM sleep. The following morning, participants identified and described waking life sources for each dream reported the previous evening. A total of 481 reports were analyzed.
"This is a new description of how dreams draw simultaneously from multiple waking-life sources, utilizing fragments of past experience to construct novel scenarios anticipating future events," said Wamsley.
According to Wamsley, the proportional increase of future-oriented dreams later in the night may be driven by temporal proximity to the upcoming events. While these dreams rarely depict future events realistically, the activation and recombination of future-relevant memory fragments may nonetheless serve an adaptive function.
The research abstract was published recently in an online supplement of the journal Sleep and will be presented as a poster beginning June 9 during Virtual SLEEP 2021. SLEEP is the annual meeting of the Associated Professional Sleep Societies, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.
https://www.sciencedaily.com/releases/2021/06/210608203711.htm
Exercise likely to be best treatment for depression in coronary heart disease
June 8, 2021
Science Daily/RCSI
A study by RCSI indicates that exercise is probably the most effective short-term treatment for depression in people with coronary heart disease, when compared to antidepressants and psychotherapy or more complex care.
The study, led by researchers at RCSI University of Medicine and Health Sciences, is published in the June edition of Psychosomatic Medicine.
This is the first systematic review to compare treatments for depression in those with coronary disease and the findings provides valuable clinical information to help doctors determine the best treatment plan for patients.
The researchers reviewed treatment trials which investigated antidepressants, psychotherapy, exercise, combined psychotherapy and antidepressants, and collaborative care (i.e. treatments devised by a multidisciplinary team of clinicians with input from the patient).
To measure effectiveness, the researchers looked at factors including patient adherence to the treatment (dropout rate) and change in depressive symptoms eight weeks after commencing treatment.
The strongest treatment effects were found to be exercise and combination treatments (antidepressants and psychotherapy). However, as the combination study results have a high risk of bias, the findings of the review suggest that exercise is probably the most effective treatment. Antidepressants had the most research support, while psychotherapy and collaborative care did not perform very well.
"Depression is common in patients with coronary artery disease. Having both conditions can have a significant impact on the quality of life for patients so it is vital that they access to the most effective treatments," commented Dr Frank Doyle, Senior Lecturer Division of Population Health Sciences, RCSI and the study's first author.
"Our study indicates that exercise is likely to be the best treatment for depression following coronary artery disease. Our findings further highlight the clinical importance of exercise as a treatment as we see that it improves not only depression, but also other important aspects of heart disease, such as lowering blood pressure and cholesterol, in these patients."
"We continue to see emerging evidence of the importance of lifestyle to treat disease -- in comparison to other treatments -- but further high-quality research is needed. People with coronary heart disease who have symptoms of depression should talk to their doctor about treatments that are most suitable for their personal needs, and clinicians can be confident of recommending exercise to their patients."
Dr Frank Doyle and the study's senior authors, Prof. Jan Sorensen (Health Outcomes Research Centre, RCSI) and Prof. Martin Dempster (School of Psychology, Queen's University Belfast), conducted the study in collaboration with researchers in the USA, The Netherlands, the UK and Denmark.
This study was also the first of its kind to establish a new method to conduct systematic reviews known as a hybrid review, which is a combination of umbrella reviews and systematic reviews.
https://www.sciencedaily.com/releases/2021/06/210608113205.htm
People who have trouble sleeping are at a higher risk of dying early - especially diabetics
June 8, 2021
Science Daily/University of Surrey
In a paper published by the Journal of Sleep Research, researchers reveal how they examined data* from half a million middle-aged UK participants asked if they had trouble falling asleep at night or woke up in the middle of the night.
The report found that people with frequent sleep problems are at a higher risk of dying than those without sleep problems. This grave outcome was more pronounced for people with Type-2 diabetes: during the nine years of the research, the study found that they were 87 per cent more likely to die of any cause than people without diabetes or sleep disturbances.
The study also found that people with diabetes and sleep problems were 12 per cent more likely to die over this period than those who had diabetes but not frequent sleep disturbances.
Malcolm von Schantz, the first author of the study and Professor of Chronobiology from the University of Surrey, said:
"Although we already knew that there is a strong link between poor sleep and poor health, this illustrates the problem starkly."
"The question asked when the participants enrolled does not necessarily distinguish between insomnia and other sleep disorders, such as sleep apnoea. Still, from a practical point of view it doesn't matter. Doctors should take sleep problems as seriously as other risk factors and work with their patients on reducing and mitigating their overall risk."
Professor Kristen Knutson of Northwestern University, the senior co-author of the study, said:
"Diabetes alone was associated with a 67 per cent increased risk of mortality. However, the mortality for participants with diabetes combined with frequent sleep problems was increased to 87 per cent. In order words, it is particularly important for doctors treating people with diabetes to also investigate sleep disorders and consider treatments where appropriate."
https://www.sciencedaily.com/releases/2021/06/210608092300.htm
High caffeine consumption may be associated with increased risk of blinding eye disease
June 7, 2021
Science Daily/The Mount Sinai Hospital / Mount Sinai School of Medicine
Consuming large amounts of daily caffeine may increase the risk of glaucoma more than three-fold for those with a genetic predisposition to higher eye pressure according to an international, multi-center study. The research led by the Icahn School of Medicine at Mount Sinai is the first to demonstrate a dietary -- genetic interaction in glaucoma. The study results published in the June print issue of Ophthalmology may suggest patients with a strong family history of glaucoma should cut down on caffeine intake.
The study is important because glaucoma is the leading cause of blindness in the United States. It looks at the impact of caffeine intake on glaucoma, and intraocular pressure (IOP) which is pressure inside the eye. Elevated IOP is an integral risk factor for glaucoma, although other factors do contribute to this condition. With glaucoma, patients typically experience few or no symptoms until the disease progresses and they have vision loss.
"We previously published work suggesting that high caffeine intake increased the risk of the high-tension open angle glaucoma among people with a family history of disease. In this study we show that an adverse relation between high caffeine intake and glaucoma was evident only among those with the highest genetic risk score for elevated eye pressure," says lead/corresponding author Louis R. Pasquale, MD, FARVO, Deputy Chair for Ophthalmology Research for the Mount Sinai Health System.
A team of researchers used the UK Biobank, a large-scale population-based biomedical database supported by various health and governmental agencies. They analyzed records of more than 120,000 participants between 2006 and 2010. Participants were between 39 and 73 years old and provided their health records along with DNA samples, collected to generate data. They answered repeated dietary questionnaires focusing on how many caffeinated beverages they drink daily, how much caffeine-containing food they eat, the specific types, and portion size. They also answered questions about their vision, including specifics on if they have glaucoma or a family history of glaucoma. Three years into the study later they had their IOP checked and eye measurements.
Researchers first looked at the relationship looked between caffeine intake, IOP and self-reported glaucoma by running multivariable analyses. Then they assessed if accounting for genetic data modified these relationships. They assigned each subject an IOP genetic risk score and performed interaction analyses.
The investigators found high caffeine intake was not associated with increased risk for higher IOP or glaucoma overall; however, among participants with the strongest genetic predisposition to elevated IOP -- in the top 25 percentile -- greater caffeine consumption was associated with higher IOP and higher glaucoma prevalence. More specifically, those who consumed the highest amount of daily caffeine- more than 480 milligrams which is roughly four cups of coffee -- had a 0.35 mmHg higher IOP. Additionally, those in the highest genetic risk score category who consumed more than 321 milligrams of daily caffeine -- roughly three cups of coffee -- had a 3.9-fold higher glaucoma prevalence when compared to those who drink no or minimal caffeine and in lowest genetic risk score group.
"Glaucoma patients often ask if they can help to protect their sight through lifestyle changes, however this has been a relatively understudied area until now. This study suggested that those with the highest genetic risk for glaucoma may benefit from moderating their caffeine intake. It should be noted that the link between caffeine and glaucoma risk was only seen with a large amount of caffeine and in those with the highest genetic risk," says co-author Anthony Khawaja, MD, PhD, Associate Professor of Ophthalmology University College London (UCL) Institute of Ophthalmology and ophthalmic surgeon at Moorfields Eye Hospital. "The UK Biobank study is helping us to learn more than ever before about how our genes affect our glaucoma risk and the role that our behaviors and environment could play. We look forward to continuing to expand our knowledge in this area."
National Eye Institute which is part of the National Institutes of Health, and New York Eye and Ear Infirmary of Mount Sinai helped to fund this study.
https://www.sciencedaily.com/releases/2021/06/210607084601.htm
Defying body clock linked to depression and lower wellbeing
June 7, 2021
Science Daily/University of Exeter
People whose sleep pattern goes against their natural body clock are more likely to have depression and lower levels of wellbeing, according to a large-scale new study.
Research led by the University of Exeter, published in Molecular Psychiatry, also found the most robust evidence to date that being genetically programmed to be an early riser is protective against major depression, and improves wellbeing. Researchers suggest this may be because society is set up to be more aligned to early risers, through the standard 9-5 working pattern.
COVID-19 has led to more flexible working patterns and this research may help make the case for more adaptable working habits to suit individuals' needs.
The team built on previous research which mapped 351 genes linked to being an early riser, or a night owl. They used a statistical process called Mendelian Randomisation to examine whether these genes were causally associated with seven mental health and wellbeing outcomes, including major depression, using data on more than 450,000 UK adults from UK Biobank's biomedical database and research resource. As well as the genetic information, participants also completed a questionnaire on whether they were a morning person or an evening person.
The team also developed a new measure of "social jetlag" that measures the variation in sleep pattern between work and free days. They measured this in more than 85,000 UK Biobank participants for whom sleep data was available, via wrist-worn activity monitors. They found that people who were more misaligned from their natural body clock were more likely to report depression and anxiety and have lower wellbeing.
Lead author Jessica O'Loughlin, of the University of Exeter, said: "We found that people who were misaligned from their natural body clock were more likely to report depression, anxiety and have lower wellbeing. We also found the most robust evidence yet that being a morning person is protective of depression and improves wellbeing.
We think this could be explained by the fact that the demands of society mean night owls are more likely to defy their natural body clocks, by having to wake up early for work."
Overall, the research team found that morning people were more likely to be aligned to their natural body clock. They then tested the effect by looking at shift workers, and found that morningness may not be protective for depression in shift workers, meaning morning people who work shifts may not have improved mental health and wellbeing, however, this was inconclusive.
Senior author Dr Jessica Tyrrell, of the University of Exeter, said: "The COVID-19 pandemic has introduced a new flexibility in working patterns for many people. Our research indicates that aligning working schedules to an individual's natural body clock may improve mental health and wellbeing in night owls."
The study is entitled 'Using Mendelian Randomization methods to understand whether diurnal preference is causally related to mental health', and published in Molecular Psychiatry. The research is supported by the Academy of Medical Sciences. The study involved collaborators from King's College London, the University of Colorado Boulder, the University of Manchester and Monash University.
https://www.sciencedaily.com/releases/2021/06/210607202226.htm
How to relax your mind before going to sleep at night.
Guest Post contribution by:David Sheptovitsky, sleepacademy.org
Difficulty falling asleep at night is a common experience for many adults. After a long day of work and caring for your family, you might think falling asleep would be a breeze. This is not the case. Many adults find it difficult to sleep due to their minds running about what they need to accomplish the next day. Thoughts are racing and anxiety is heightened making it much more difficult to relax your mind and have a proper night's sleep. Rather than turning to sleeping pills or other unnatural means to help you fall asleep, focusing on calming your body and relaxing your mind can be the most beneficial way to fall asleep and stay asleep at night after a stressful day. Below are some strategies to help promote relaxation in the mind and body before bed.
Tips to keep in mind before attempting any relaxation strategies:
The ultimate goal of any relaxation strategies before you are going to bed is to lower your heart rate and blood pressure, as well as to enable slow, deep breathing. These factors create an increased sense of well-being. Any strategies you use to promote body and mind relaxation should all create those results.
While keeping those factors in mind, along with whatever relaxation strategies you choose to do, keeping a balanced sleeping schedule will also be beneficial in creating the best results for falling asleep faster. It is also important to keep in mind these relaxation strategies might take some practice before they are able to work in full effect. Ongoing practices of relaxation techniques are much more effective than short-term use. Lastly, It is important to be aware of what specific exercises work for you. Not all relaxation exercises may be effective for you. Only you know your body best and if you feel like one exercise just isn't cutting it, focusing on a new exercise to relax your mind may be more beneficial.
Relaxation Strategies:
Visualization Exercises:
A way of engaging in your body's natural relaxation process is visualization exercises. These exercises focus on using mental images to create a sense of well-being and promote a stress-free environment for sleeping.
Autogenic Training: Autogenic training hyper focuses on the heaviness and warmth of each part of your body. The overall idea of this training is to be able to calm different parts of your body at any time. Below are the steps of Autogenic Training:
- Start with a few minutes of controlled breathing
- After breathing, focus on a single part of your body. For example your hands. Then say back to yourself “ My hands are very heavy, I am completely calm”. Say this a few times.
- Then say, “ My hands are very warm, I am completely calm”. Repeat this a few times.
- Repeat this process as many times as you feel needed, and to as many body parts as you feel needed.
Body Scan: A body scan is a type of meditation that calms different parts of your body. The goal of this exercise is to be able to calm your body parts to promote a relaxed mind. Below are the steps of Body Scan:
- Start with a few minutes of controlled breathing
- Focus on a specific body part, for example, your hands. Notice if they hold any tension in your palms or fingers
- If there is any tension, visualize this tension leaving your hands and body. This can be through mental visualization or through controlled breathing
- Repeat this process as many times as you feel needed, and to as many body parts as you feel needed.
Breathing Exercises:
Controlled breathing is one of the body's most basic ways to engage in a state of relaxation. Overall, decreasing the speed of your breathing and focusing on the depths of your breaths can be beneficial in promoting a calm mind and body. These breathing exercises will help you create a stress-free environment that promotes a relaxed mind and body for a good night's rest.
4-7-8 Breathing: This exercise is an advanced breathing exercise. If you are not comfortable holding your breath, this exercise may not be great to promote a stress-free mind. The steps are below as follows:
- Place your tongue on the roof of your mouth, right behind your top, front teeth. Your tongue will remain here for the duration of the exercise
- Inhale through your nose for 4 seconds
- Hold your breath for 7 seconds
- Exhale through your mouth for 8 seconds
- Repeat as many times as needed
Diaphragmatic Breathing: This is a much simpler breathing exercise. This technique targets your belly, rather than lungs. This focuses on reducing stress while strengthening your diaphragm. The steps are below as follows:
- In a lying down position, place one hand on your chest and one hand on your belly, right below your rib cage.
- Breath in through your nose, and feel your belly push against your hand. You should try to keep the rest of your body as still as possible.
- While keeping your chest still, tighten your stomach muscles and exhale through your mouth.
- Repeat as many times as needed
Sleep should be a priority in your life. A good night’s sleep is essential to participate in your daily activities to the fullest of your ability. Trouble falling asleep at night is something commonly struggled with by adults. Stressful days can turn over into stressful, sleepless nights. These exercises above promote relaxation in both your mind and body. Keeping a stress-free mind and body can result in falling asleep quicker, as well as staying asleep longer. Try a few of the practices above and see which relaxation techniques work best for you.
“Relaxation Exercises to Help Fall Asleep.” Sleep Foundation, 18 Dec. 2020, www.sleepfoundation.org/sleep-hygiene/relaxation-exercises-to-help-fall-asleep.
Margarita Tartakovsky, M.S. “12 Ways to Shut Off Your Brain Before Bedtime.” Psych Central, Psych Central, 17 May 2016, psychcentral.com/lib/12-ways-to-shut-off-your-brain-before-bedtime#6.
10 Tips For New Moms
Guest post by: Dema Sawaqed
You have just given birth and are experiencing a mixture of excitement, pride, immense joy, and fatigue.
In short, nothing more normal.
And while you think you are, well, quiet at least for a few weeks, reality forces itself on you, sometimes a little abruptly.
To prepare yourself as much as possible and be calm, here are the 10 things to do after your pregnancy:
Let’s get started,
1. Express your feelings
As 50 to 80% of young mothers, pregnancy and childbirth may give way, for a few days (or just a few hours) to a baby blues.
Do not panic!
This is perfectly normal and should dissipate quickly.
But to deal with you as easily as possible, it is highly recommended to talk about it and especially not to keep it to yourself.
Share your thoughts with anyone you think can understand and help you deal with it. Like your health staff, partner, family member, or friend.
2. Postpartum consultation
We may think (and wish) that childbirth is the end of medical visits of all kinds, Nay!
Mothers should quickly think about the post-natal consultation (within six to eight weeks after birth).
3. Resumption of contraception
Even if this is not really our main concern during a stay in the maternity hospital, it should be considered if you do not want to immediately follow a second pregnancy.
You might as well take advantage of the presence of professionals to ask questions and choose your contraceptive method.
4. Learn to let go
This is one of the main keys to remaining calm and taking on your new role as a mom while ensuring the daily tasks.
The trick?
Do not hesitate to ask those around you!
5. Take care of your marital life to avoid the baby clash
Needless to say…
The arrival of a child within a couple changes things considerably!
The spouse suddenly becomes a parent, and the couple becomes a family, with the key to new situations to manage and new roles to assume.
It is thus common that the first months following a birth generate difficulties, even a real upheaval, which can go as far as separation.
To avoid this,
..take care of your marital life as soon as possible and as much as you can!
6. Think about yourself and have fun
… But we also think of ourselves!
Forgetting yourself by living only for your little one is not the best solution.
Allow yourself moments of pleasure just for yourself that you can be completely fulfilled.
And as known: Happy mom.. Happy baby!
7. Do some sports
Of course, we all want to find the line quickly after pregnancy.
Only here, things are not so simple, and each woman is different on this point.
Rule?
Wait for the post-natal consultation and the doctor's opinion, then take it easy if there are no contraindications.
Walking, swimming, cycling or yoga are recommended to start.
Jogging or tennis are to be avoided.
8. Anticipate returning to work
It is the best way of returning to an active life without too much stress.
Anticipating means finding a childcare arrangement and organizing future days according to work and transport schedules
...but also discussing with your employer to possibly adjust their schedules to help you take care of your little one.
9. Find childcare for your baby
Babysitter or childcare center?
In all cases, the choice of childcare must be anticipated from the time of pregnancy, to allow the baby and the mother to be confident and perfectly reassured.
10. Enjoy!
With all these things to do, we would almost forget the essential: enjoying your baby and every moment spent together!
Time flies by so fast..
Remember to enjoy your little one being so little as much as you can!
About
Dema JS is the founder of newbabysmell.com and a mother of two little kids.
Dema had her MBA from St. John’s University- NYC in dual concentrations: Executive Management and Marketing Management.
Contact: Please email dema@newbabysmell.com or go to newbabysmell.com
Early bird or night owl? Study links shift worker sleep to 'chronotype'
Sleep styles may hold the key to designing better work schedules
June 1, 2021
Science Daily/McGill University
Getting enough sleep can be a real challenge for shift workers affecting their overall health. But what role does being an early bird or night owl play in getting good rest? Researchers from McGill University find a link between chronotype and amount of sleep shift workers can get with their irregular schedules.
"Some people seem to be hardwired to sleep early, while others tend to sleep late. This preference, called chronotype, is modulated by our circadian system -- each person's unique internal timekeeper," says lead author Diane B. Boivin, a Professor in the Department of Psychiatry at McGill University.
Their study published in Sleep is the first to examine the relationship between chronotype and sleep behaviour in shift workers during morning, evening, and night shifts. To investigate this relationship, the researchers tracked 74 police officers as they worked their usual shifts. For close to a month, the officers wore a watch-like device, allowing researchers to measure their sleep.
Not all shifts created equal
"Our results suggest that the effect of chronotype on sleep duration and napping behavior depends on the shift type. On average early risers sleep 1.1 hours longer on morning shifts, while night owls sleep two hours longer on evening shifts," says co-author Laura Kervezee, a former Postdoctoral Fellow at The Douglas Research Centre affiliated with McGill University.
The power of naps
While shift workers take naps to reduce the effect of their irregular schedules on their sleep, the researchers found this behaviour was more prominent during night shifts in early risers. Generally, early risers slept less after night shifts compared to night owls -- but they also took more naps prior to their night shifts, so their total daily sleep was similar.
The findings could help design strategies to improve sleep in workers with atypical schedules, the researchers say. Such strategies could include work schedules that consider chronobiological principles.
"People involved in shift work experience an increased risk of sleep disturbances and fragmented sleep periods. Since sleep is essential for optimal performance, health, and well-being, it's important to develop strategies to get better rest," says Boivin, who is also the Director of the Centre for Study and Treatment of Circadian Rhythms at The Douglas Research Centre.
As next steps, the researchers hope to study the impact of chronotype and shift work on other health outcomes.
https://www.sciencedaily.com/releases/2021/06/210601135727.htm
How to boost muscle regeneration and rebuild tissue
Muscle cells tissue illustration (stock image). Credit: © gen1607 / stock.adobe.com
Clues about molecular changes underlying muscle loss tied to aging
May 25, 2021
Science Daily/Salk Institute
One of the many effects of aging is loss of muscle mass, which contributes to disability in older people. To counter this loss, scientists at the Salk Institute are studying ways to accelerate the regeneration of muscle tissue, using a combination of molecular compounds that are commonly used in stem-cell research.
In a study published on May 25, 2021, in Nature Communications, the investigators showed that using these compounds increased the regeneration of muscle cells in mice by activating the precursors of muscle cells, called myogenic progenitors. Although more work is needed before this approach can be applied in humans, the research provides insight into the underlying mechanisms related to muscle regeneration and growth and could one day help athletes as well as aging adults regenerate tissue more effectively.
"Loss of these progenitors has been connected to age-related muscle degeneration," says Salk Professor Juan Carlos Izpisua Belmonte, the paper's senior author. "Our study uncovers specific factors that are able to accelerate muscle regeneration, as well as revealing the mechanism by which this occurred."
The compounds used in the study are often called Yamanaka factors after the Japanese scientist who discovered them. Yamanaka factors are a combination of proteins (called transcription factors) that control how DNA is copied for translation into other proteins. In lab research, they are used to convert specialized cells, like skin cells, into more stem-cell-like cells that are pluripotent, which means they have the ability to become many different types of cells.
"Our laboratory previously showed that these factors can rejuvenate cells and promote tissue regeneration in live animals," says first author Chao Wang, a postdoctoral fellow in the Izpisua Belmonte lab. "But how this happens was not previously known."
Muscle regeneration is mediated by muscle stem cells, also called satellite cells. Satellite cells are located in a niche between a layer of connective tissue (basal lamina) and muscle fibers (myofibers). In this study, the team used two different mouse models to pinpoint the muscle stem-cell-specific or niche-specific changes following addition of Yamanaka factors. They focused on younger mice to study the effects of the factors independent of age.
In the myofiber-specific model, they found that adding the Yamanaka factors accelerated muscle regeneration in mice by reducing the levels of a protein called Wnt4 in the niche, which in turn activated the satellite cells. By contrast, in the satellite-cell-specific model, Yamanaka factors did not activate satellite cells and did not improve muscle regeneration, suggesting that Wnt4 plays a vital role in muscle regeneration.
According to Izpisua Belmonte, who holds the Roger Guillemin Chair, the observations from this study could eventually lead to new treatments by targeting Wnt4.
"Our laboratory has recently developed novel gene-editing technologies that could be used to accelerate muscle recovery after injury and improve muscle function," he says. "We could potentially use this technology to either directly reduce Wnt4 levels in skeletal muscle or to block the communication between Wnt4 and muscle stem cells."
The investigators are also studying other ways to rejuvenate cells, including using mRNA and genetic engineering. These techniques could eventually lead to new approaches to boost tissue and organ regeneration.
https://www.sciencedaily.com/releases/2021/05/210525113717.htm
Stair climbing offers significant cardiovascular and muscular benefits for heart patients
May 17, 2021
Science Daily/McMaster University
A team of McMaster University researchers who studied heart patients found that stair-climbing routines, whether vigorous or moderate, provide significant cardiovascular and muscular benefits.
The findings, published in closely related studies in the journals Medicine & Science in Sports & Exercise and Frontiers, address the most frequently cited barriers to exercise: time, equipment and access to gym facilities.
"Brief, vigorous stair-climbing and traditional moderate intensity exercise both changed fitness, which is a key predictor of mortality after a cardiac event," says Maureen MacDonald, one of the lead researchers on both studies and a professor in McMaster's Department of Kinesiology.
"We've shown stair-climbing is a safe, efficient and feasible option for cardiac rehabilitation, which is particularly relevant during the pandemic when many people don't have the option to exercise in a gym," she says.
While it is widely known that exercise and lifestyle changes reduce the risk of secondary cardiovascular disease, statistics suggest less than a quarter of all cardiac patients adhere to fitness programs.
Researchers worked closely with the Cardiac Health and Rehabilitation Centre at the Hamilton General Hospital to develop an exercise protocol that did not require specialized equipment or monitoring and could be easily performed outside a laboratory.
Participants with coronary artery disease who had undergone a cardiac procedure were randomly assigned either to traditional moderate-intensity exercise or vigorous stair climbing: three rounds of six flights of 12 stairs, separated by recovery periods of walking, with participants selecting their own stepping pace.
Researchers compared the results and found that individuals who had done traditional exercise and those who had done stair-climbing both increased their cardiorespiratory fitness after four weeks of supervised training and maintained those levels for an additional eight weeks of unsupervised training.
They also reported substantial muscular improvement.
"These patients who had undergone a coronary bypass or stent procedure had muscle that was compromised, compared to age-matched healthy controls," explained Stuart Phillips, a co-author of the studies and a professor in the Department of Kinesiology at McMaster who oversaw the analysis of muscle tissue taken during the study.
Previously, there had been very few studies of the impact of exercise on cardiac patients' muscle specifically. This analysis shows heart patients can still repair and build lost muscle.
"Even in just a short period, whether it was moderate intensity, continuous training or high-intensity stair climbing, there were beneficial adaptations in muscles after a cardiac procedure," Phillips says. "The improvements were clear."
https://www.sciencedaily.com/releases/2021/05/210517102635.htm
Scientists identify mechanism linking traumatic brain injury to neurodegenerative disease
June 1, 2021
Science Daily/eLife
Scientists have revealed a potential mechanism for how traumatic brain injury leads to neurodegenerative diseases, according to a study in fruit flies, and rat and human brain tissue, published today in eLife.
The results could aid the development of treatments that halt the progression of cell damage after brain injury, which can otherwise lead to neurological diseases such as amyotrophic lateral sclerosis (ALS), and Alzheimer's and Parkinson's disease.
Repeated head trauma is linked to a progressive neurodegenerative syndrome called chronic traumatic encephalopathy (CTE). Postmortem tissues from patients with CTE show dysfunctional levels of a molecule called TDP-43, which is also found in ALS, Alzheimer's disease and frontotemporal dementia.
"Although TDP-43 is a known indicator of neurodegeneration, it was not clear how repeated trauma promotes the build-up of TDP-43 in the brain," explains first author Eric Anderson, Postdoctoral Research Associate at the Department of Pediatrics at the University of Pittsburgh, Pennsylvania, US. "We have shown that repetitive brain trauma in fruit flies leads to a build-up of TDP-43. In this study we measured the changes of proteins in the fruit fly brain post injury to identify the molecular pathways that cause this."
From an analysis of 2,000 proteins, the team identified 361 that significantly changed in response to injury. These included components of the nuclear pore complex (NPC) involved in nucleocytoplasmic transport -- the shuttling of important cargoes between the cell nucleus and the rest of the cell.
They found that a family of molecules that make up the NPC called nucleoporins (Nups) were increased in both larval and adult flies after injury. When they looked at the distribution pattern of Nups around the edge of the nucleus in fruit fly nerve cord cells, they found it was altered after brain trauma: there were gaps in the nuclear membrane and clumps of Nups. They also found changes in a key enzyme involved in transporting molecules in and out of the nucleus in injured brains. As a result, the transport of fluorescently labelled cargo in and out of the nucleus was impaired.
Having established that brain injury impairs the transport machinery between the nucleus and the rest of the cell, the team looked at whether the build-up of Nups leads to the aggregation of TDP-43 seen in neurodegenerative diseases. They created fruit flies that produce excess Nup protein and then stained the brain cells for the fruit fly version of TDP-43, called Tbph. They found a significant increase in the number of Tbph deposits in brains that had too much Nup compared with normal brains. Moreover, these high levels of Nups were also toxic to the flies, causing decreased motor function and reducing the distance they could climb in a certain timeframe. When the level of Nups was reduced in cells after injury, this improved the flies' climbing ability and lifespan, highlighting an avenue to explore for new treatments.
Finally, the team looked at whether the increased build-up of a Nup molecule (Nup62) was also seen in human brain tissue after injury. They examined postmortem brain tissue from patients with mild and severe CTE matched to healthy tissue from people of the same age. All mild and severe patients were involved in sports, while healthier cases were not. They found that Nup62 was present in large amounts in the wrong place in patients with mild and severe disease, but not in the healthy group, and the degree of Nup62 aggregation increased with the severity of disease. They also saw similar changes in the distribution of Nup62 in a rat model of traumatic brain injury.
"Our study reveals that traumatic brain injury can disrupt nuclear transport machinery of the cells, which plays an essential role in normal cell functions such as communication," concludes senior author Udai Pandey, associate professor of pediatrics, human genetics and neurology at the University of Pittsburgh School of Medicine. "This suggests that the accumulation of neurodegenerative hallmark proteins caused by injury begins with these nuclear transport defects, and that targeting these defects could be a strategy for preventing trauma-induced neurological disorders."
https://www.sciencedaily.com/releases/2021/06/210601135830.htm
Gut to brain: Nerve cells detect what we eat
June 2, 2021
Science Daily/Max-Planck-Gesellschaft
The gut and the brain communicate with each other in order to adapt satiety and blood sugar levels during food consumption. The vagus nerve is an important communicator between these two organs. Researchers from the Max Planck Institute for Metabolism Research in Cologne, the Cluster of Excellence for Ageing Research CECAD at the University of Cologne and the University Hospital Cologne now took a closer look at the functions of the different nerve cells in the control centre of the vagus nerve, and discovered something very surprising: although the nerve cells are located in the same control center, they innervate different regions of the gut and also differentially control satiety and blood sugar levels. This discovery could play an important role in the development of future therapeutic strategies against obesity and diabetes.
When we consume food, information about the ingested food is transmitted from the gastrointestinal tract to the brain in order to adapt feelings of hunger and satiety. Based on this information, the brain decides, for example, whether we continue or stop eating. In addition, our blood sugar level are adapted by the brain. The vagus nerve, which extends from the brain all the way down to the gastrointestinal tract, plays an essential role in this communication. In the control center of the vagus nerve, the so-called nodose ganglion, various nerve cells are situated, some of which innervate the stomach while others innervate the intestine. Some of these nerve cells detect mechanical stimuli in the different organs, such as stomach stretch during feeding, while others detect chemical signals, such as nutrients from the food that we consume. But what roles these different nerve cells play in transmitting information from the gut to the brain, and how their activity contributes to adaptations of feeding behavior and blood sugar levels had remained largely unclear.
"To investigate the function of the nerve cells in the nodose ganglion, we developed a genetic approach that enables us to visualize the different nerve cells and manipulate their activity in mice. This allowed us to analyze which nerve cells innervate which organ, pointing to what kind of signals they detect in the gut," says study leader Henning Fenselau. "It also allowed us to specifically switch on and off the different types of nerve cells to analyze their precise function."
Different food activates different nerve cells
In their studies, the researchers focused primarily on two types of nerve cells of the nodose ganglion, which is just one millimeter in size. "One of these cell types detects stomach stretch, and activation of these nerve cells causes mice to eat significantly less," Fenselau explains. "We identified that activity of these nerve cells is key for transmitting appetite-inhibiting signals to the brain and also decreasing blood sugar levels." The second group of nerve cells primarily innervates the intestine. "This group of nerve cells senses chemical signals from our food. However, their activity is not necessary for feeding regulation. Instead, activation of these cells increases our blood sugar level," says Fenselau. Thus, these two types of nerve cells in the control center of the vagus nerve fulfil very different functions.
"The reaction of our brain during food consumption is probably an interplay of these two nerve cell types," Fenselau explains. "Food with a lot of volume stretches our stomach, and activates the nerve cell types innervating this organ. At a certain point, their activation promotes satiety and hence halts further food intake, and at the same time coordinates the adaptations of blood sugar levels. Food with a high nutrient density tends to activate the nerve cells in the intestine. Their activation increases blood glucose levels by coordinating the release of the body's own glucose, but they do not halt further food intake." The discovery of the different functions of these two types of nerve cells could play a crucial role in developing new therapeutic strategies against obesity and diabetes.
https://www.sciencedaily.com/releases/2021/06/210602130330.htm