Sci-Ed Update 282

Human microbiome, transplanted uterus birth, histology teaching, brain's sense of self, and more!

Aug 04, 2023

Your gut microbiome is linked to your fitness and biological age

Altering the gut microbiome via probiotics could one day help people to maintain a certain level of fitness and reduce the rate of their biological ageing

*The gut microbiome is increasingly being linked to different aspects of health, which may include a person’s fitness and their biological age Oleksandra Troian/Getty Images*

The diversity of microbes in the gut could affect a person’s fitness and their biological age. Better understanding this may one day lead to probiotics that alter the gut’s microbial make-up to promote health.
Zsolt Radak at the Hungarian University of Sports Science and his colleagues studied 80 amateur rowers, aged 38 to 84, who participated in the 2019 World Rowing Masters Regatta in Velence, Hungary.
The rowers, whose training regimens ranged from practising every day to once a week, each provided a stool sample to identify the bacteria in their guts. The researchers also took blood samples to gauge the participants’ biological ages – a measure based on DNA markers, rather than the number of years someone has been alive.
To assess fitness, the rowers took part in various tests, for example one that measured their hand grip strength and another that calculated their maximum oxygen uptake, a measure of cardiovascular fitness.
The researchers found that having higher levels of gut microbiome diversity was linked to lower levels of fitness and an accelerated rate of biological ageing. This somewhat goes against previous research that linked lower gut microbial diversity to conditions such as obesity and type 2 diabetes.
“If all the bacteria were beneficial, then OK, it’s very simple to say, ‘the more diversity, the better’,” says Radak. “But with different kinds of infections, the diversity of the pathogens also increases. There are a number of bacteria whose function is still poorly understood.”

Irregular sleep linked to harmful gut bacteria, study suggests

Multiple links were found between social jet lag, diet quality, diet habits, inflammation, and gut microbiome composition

Irregular sleep patterns may be linked to harmful bacteria in your gut, new research suggests.
The study is the first to find multiple associations between social jet lag – the shift in internal body clock when sleeping patterns change between workdays and free days – and diet quality, diet habits, inflammation and gut microbiome (bacteria) composition.
According to the findings, even a 90-minute difference in the midpoint of sleep – half-way between sleep time and wake-up time – can encourage microbiome that has negative associations with health.
Previous research has suggested that working shifts disrupts the body clock and can increase risk of weight gain, heart problems and diabetes.
However, according to researchers from King’s College London there is less awareness that the body’s biological rhythms can be affected by smaller inconsistencies in sleeping patterns.

Human microbiome myths and misconceptions

Changes in faecal microbiota have been associated with a range of diseases in humans. Interestingly, despite the diverse nature of these conditions, and the organs they affect, there are some broadly common recurring microbiota features, such as reduced diversity and increases in facultative anaerobes like Enterobacteriaceae. One common theme amongst these conditions is that they often result in increased levels of inflammation, at local and systemic levels. Such inflammation can, in turn, deplete the gut microbiota (and consequently microbial gene diversity), and allow facultative anaerobes such as Enterobacteriaceae to proliferate. This directly impacts the metabolic output of the microbiota, and its interactions with the host. Additionally, there are other host factors that contribute to disease and gut microbiota composition, such as age, BMI and medication, as well as host metabolism and immune response. This makes it very difficult to distinguish cause from effect in correlation-based studies.

Over the past two decades, interest in human microbiome research has increased exponentially. Regrettably, this increased activity has brought with it a degree of hype and misinformation, which can undermine progress and public confidence in the research. Here we highlight selected human microbiome myths and misconceptions that lack a solid evidence base. By presenting these examples, we hope to draw increased attention to the implications of inaccurate dogma becoming embedded in the literature, and the importance of acknowledging nuance when describing the complex human microbiome.

The Human Microbial System

The human microbiome is rapidly emerging as an important character in the story of human structure and function. Perhaps we should start thinking of it alongside the other major systems of the body—as the human microbial system (HMS).

To listen to this episode, click on the player (if present) or this link→ theAPprofessor.org/podcast-episode-47.html

Skin’s Microbiome & Other Stories

persons left hand on black textile — *Photo by Nsey Benajah on Unsplash*

Revisiting the concept of the microbiome—this time focusing on the skin microbiome—Kevin finds an excuse to provide a Word Dissection and tell some stories from the olden days. This segment serves as an unnecessarily long prelude to the current recommendation in The A&P Professor Book Club, described in a later segment.

To listen to this episode, click on the player (if present) or this link→ theAPprofessor.org/podcast-episode-114.html

How the Brain Creates Your Physical Sense of Self

New insight comes from zapping a region, known as the anterior precuneus, that causes people to feel dissociated from their body

The 19th-century philosopher William James proposed that the self could be split into two parts. The first was an “I” that physically perceives and experiences the world, and the second was a “me” that encompasses a mental narrative about oneself, based on one’s past experiences. Neuroscientists equipped with high-tech tool kits have begun to achieve some success in the long-running search to find the brain areas responsible for creating these two aspects of the self.
The discovery of “me” came first. The default-mode network, a term coined by neurologist Marcus Raichle in 2001, has emerged as a key player in the “me” aspect of the self. This collection of brain areas is active when a person is not focused on a task, and researchers have found that it plays an important role in processing self-referential thoughts. “[This network] has kind of been baptized as the center for the sense of self,” says Josef Parvizi, a neurologist and a professor at Stanford University who researches the self.
The “I,” in contrast, has been harder to pin down—at least until very recently. The awareness we have that we inhabit a body (call it an essential “I-ness”) forms a bridge that constantly switches back and forth between a conscious and unconscious state of mind. Suppose you’re sitting at the kitchen table or standing waiting for a train. Unless you’re in pain, you have no moment-by-moment awareness of your hand, your shin, your big toe or even your body as a whole. But as soon as you think of any of these spots, you can feel their presence immediately. “I-ness” is that feeling that you indeed occupy your own body.

Woman With Transplanted Uterus Gives Birth to Boy

July 27, 2023 – A woman who was born without a uterus has given birth to a boy in Alabama.
It’s the first time that a baby has been born to a woman with a transplanted uterus outside of a clinical trial. Officials from University of Alabama-Birmingham Hospital, where the 2-year process took place, said in a statement this week that the birth sets its uterus transplant program on track to perhaps become covered under insurance plans.
The process of uterus transplant, in vitro fertilization, and pregnancy involves 50 medical providers and is open to women who have a condition called uterine factor infertility, or UFI. The condition may affect up to 5% of reproductive-age women worldwide. Women with UFI cannot carry a pregnancy to term because they were either born without a uterus, had it removed via hysterectomy, or have a uterus that does not function properly.

Failing to Succeed

We must celebrate scientific failures not as precedents to anticipatory successes but for what they are: valiant efforts that didn’t work out.

In 1928, Alexander Fleming noticed a mold infiltrating his Staphylococcus bacteria culture plates. Fleming observed that the intruder inhibited bacterial growth and eventually found the causative antibiotic: penicillin.
This story of a serendipitous groundbreaking discovery from a mishap is an inspiration to all scientists. It offers hope that even if an experiment fails, something extraordinary may come out of it. While everyone needs this motivation to keep going on rough days, such success stories set unrealistic expectations of a strong comeback. A more realistic scenario is that researchers lose time, samples, and effort, with no compensatory gains.
Survivorship bias runs rampant in science. As journalists, we are privileged to cover cutting edge research and inform the community about seminal updates in life science. We report on the best publications and shine a spotlight on the study authors for their wins. These articles keep researchers motivated, informed, and excited about science, but reading only about successes makes them feel like the norm, even if these big advances are rare. This feeds the monster of imposter syndrome in an already frail “publish or perish” academic ecosystem wherein failure may feel shameful.
So, what can we do about it? Failing is normal, but we need to normalize talking about it. Sometimes scientists fail and then eventually succeed, and sometimes they simply fail to succeed. We want to normalize both scenarios. As a step in this direction, I am thrilled to introduce our new column, “Epic Fail,” which will provide an outlet for scientists to share their failures.
In our first column, Gaurav Ghag from Gilead Sciences shared how he handled the disastrous realization that he had replicated a calculation error in an experiment over the course of four years during his graduate work.

Kevin Patton comment→ Follow the link to read “My Protein Didn’t Fold and Neither Did I” by Gaurav Ghag. I think stories of failure also help our students understand that the accomplishment of goals necessarily involves both failures and successes.

A Brain MicroRNA Curbs Anxiety

Upregulation of a specific microRNA in the brain lessened anxiety and reduced the expression of stress-related genes in mice.

Mosienko’s team performed fluorescence in situ hybridization on mouse amygdala such as the one pictured above. The expression of miR-483-5p is shown in green. Red indicates the expression of a neuronal marker, while the purple color represents the expression of a synapse marker. MARIUSZ MUCHA

Stress is a known risk factor for anxiety disorders, which affected more than 300 million people worldwide in 2019.¹ While antianxiety medications exist, these drugs do not work for everyone. Valentina Mosienko, a neuroscientist at the University of Bristol, strongly believes that we need better treatments for anxiety, but the first step is to understand its molecular basis.
With that in mind, she and her team explored microRNA since altered levels link to psychiatric disorders.² How microRNA regulates stress in the brain is largely unknown. In a recent Nature Communications publication, Mosienko and her colleagues reported the role of a specific microRNA, miR-483-5p, in stress-induced anxiety in mice.³
Mosienko and her colleagues focused on the amygdala, a brain region implicated in anxiety and control of the stress response. The team stressed mice by restricting their movements and harvested their amygdalae to detect microRNA expression changes. Stress increased the expression of a handful of microRNAs, among which miR-483-5p was the most upregulated. The team also found that miR-483-5p downregulated stress-related genes, particularly Pgap2, in neuronal cell cultures exposed to a synthetic stress hormone.

Kevin Patton comment→ One answer to the question, “should I mention microRNAs to my A&P students?”

Online, Interactive, Digital Visualisation Resources that Enhance Histology Education

Teaching histology is expensive, particularly in some universities with limited or ageing resources such as microscope equipment and inadequate histological slide collections. Increasing numbers of student enrolments have required duplications of laboratory classes. Such practical classes are staff intensive and so teaching hours are increased. Technology can now solve many of these issues but perhaps, more importantly, can also cater to the self-directed and independent learning needs of today’s learners.
This chapter will describe and evaluate distinct innovations available on a global scale, utilising both technology-enhanced and interactive learning strategies to revolutionise histology teaching via successful online delivery of learning resources. Histology students can access these innovations to maximise their learning and enable them to complete all learning outcomes away from the traditional classroom environment (i.e., online). Most appropriately, all of these innovations address and help solve cognitive challenges that students experience in histology learning.

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