Comment

Comment by Dr. Krishna Kumari Challa on June 8, 2024 at 9:21am

Highlights of the study:

• •An early study to detect microplastics in semen from a general population cohort
• •Eight MP polymer types were identified, with PS, PE, and PVC most prevalent.
• •Raman microspectroscopy enabled sub-micron microplastic characterization.
• •PS and PVC correlated with differential effects on sperm motility.

• As widespread environmental pollution, MPs/NPs raise concerns about reproductive toxicity.

• •

  Infertility affects 15 % couples globally, with environmental factors playing a significant role.

• •

  Limited understanding of MPs/NPs effects on testes and ovaries necessitates further research.

• •

  Contaminants carried by particles may synergistically contribute to reproductive toxicity.

https://www.sciencedirect.com/science/article/pii/S0048969723048830

Part 2

Comment by Dr. Krishna Kumari Challa on June 8, 2024 at 9:05am

Microplastics found in every semen sample tested by research team
A team of public health researchers affiliated with multiple institutions in China has found microplastics in the semen of every sample they tested. In their study, published in the journal Science of the Total Environment, the group looked for microplastics in semen samples obtained from 36 healthy adult men.

Prior research has shown that microplastics are nearly everywhere, found on mountaintops, remote islands in the upper atmosphere and the depths of the world's oceans. They have also been found in every organ in the human body.

In a recent discovery, scientists found that the average person consumes plastic in amounts equal to about one credit card every week. The researchers note that plastics can enter the body in multiple ways, such as through drinking from water bottles, breathing air particulates, or eating food heated in plastic containers. They further note that it is now practically impossible for people to avoid ingesting microplastics.

The health impacts remain unknown, but many scientists around the world are looking into it, suspecting microplastic ingestion may be behind many inflammatory diseases.
In this new effort, the research team wondered if ingested microplastics might be behind the global drop in fertility rates. To find out, they recruited 36 healthy adult males living in the city of Jinan, in the eastern part of China, who did not work in the plastics industry—each donated a sample of semen for testing.

Each of the samples was prepared by mixing it with a chemical solution then filtered for analysis by a team member using a microscope. The researchers found microplastics in every sample. They also found eight types of plastics, the most common of which was polystyrene, which is commonly used in packaging foam.
The team also found lower sperm motility in the semen samples containing polyvinyl chloride plastic bits, a finding that may help explain the decline in fertility rates.

Ning Li et al, Prevalence and implications of microplastic contaminants in general human seminal fluid: A Raman spectroscopic study, Science of The Total Environment (2024). DOI: 10.1016/j.scitotenv.2024.173522

Comment by Dr. Krishna Kumari Challa on June 8, 2024 at 6:56am

Timing drug administration to endogenous circadian rhythms may enhance treatment efficacy

Taking blood pressure medication at a time that aligns with your personal chronotype – the way your body's circadian rhythm affects when you go to sleep and get up – could help to protect the heart against the risk of heart attack, a new study shows.

It may be beneficial for night owls to take their medication in the evening, and for early birds to take it in the morning. These timings seem to offer some protection against the risks associated with BP (also known as hypertension). The international team of researchers behind the new study looked at records for more than 5,300 individuals, who answered questions about their chronotype, before being randomly split into groups and instructed to take their blood pressure meds at different times. Participants were then monitored over several months. These results are exciting because they could represent a paradigm shift in the treatment of hypertension. This research has now shown for the first time that considering chronotype when deciding [the] dosing time of antihypertensives – [a strategy called] personalized chronotherapy – could reduce the risk of heart attack. Each person's circadian rhythm (24-hour biological cycle) varies slightly, based on genetics and other factors. These rhythms are well known for influencing our sleep patterns, but they also help to dictate body temperature, hormones, metabolism – and, importantly for this study, BP levels. If blood pressure cycles up and down throughout the day, the time that medications are taken might matter, the researchers hypothesized.

https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(24)...

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 7:23am

Bird flu in cows could spread through milk
Astonishing amounts of H5N1 virus have been found in the raw milk of cows infected with avian influenza. The virus can survive for hours in splattered milk. This reinforces that the milking process is probably driving transmission among cows and might be spreading the virus to humans. The fact that H5N1 doesn’t seem to spread through airborne particles is good news. It means changes to milking procedures — such as disinfecting equipment between cows and protective equipment to farm workers — could help to bring the outbreak under control.

Nature | 5 min read
Reference: bioRxiv preprint & medRxiv preprint (not peer reviewed)

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 7:20am

Dad’s diet affects sons’ health

Epigenetic inheritance of diet-induced and sperm-borne mitochondrial RNAs

A father’s sperm records his diet, which affects his sons’ metabolism — in both mice and in humans. The male offspring of mice that ate high-fat foods were more likely to have problems such as glucose intolerance, a characteristic of diabetes. And the sons of human dads with a high body-mass index had similar problems, according to an analysis of more than 3,000 children. In mice, an unhealthy diet changed certain types of sperm RNA, which could alter the offspring’s epigenome — the collection of chemical tags hanging from DNA and its associated proteins. Why this seems to only affect sons is “a very good question for future studies."

https://www.nature.com/articles/s41586-024-07472-3?utm_source=Live+...

https://www.nature.com/articles/d41586-024-01623-2?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 7:05am

The experiments showed that nanoparticles in placental tissue disrupt the production of a large number of messenger substances. And it is these messengers that can trigger serious changes in embryonic development, such as disturbed blood vessel formation.
These effects can be visualized in laboratory models using chicken eggs. The blood vessels in the egg actually grow at an enormous speed and density to enable embryonic development. A dense network of fine blood vessels covers the inside of the eggshell.

The situation is strikingly different in eggs treated with the altered messenger substances from the nanoparticle-treated placenta: In the experiments, the blood vessel system was not as dense but rather coarse-meshed. "Nanoparticles apparently have an indirect effect on the child in the womb by inhibiting the formation of blood vessels via messenger substances.
The researchers are currently investigating the health consequences of this.

Battuja Dugershaw‐Kurzer et al, Nanoparticles Dysregulate the Human Placental Secretome with Consequences on Angiogenesis and Vascularization, Advanced Science (2024). DOI: 10.1002/advs.202401060

Part 2

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 7:03am

Study links nanoparticles to altered blood vessel formation in embryos

Human life begins with a single egg cell that grows into a human being with trillions of cells. To ensure that the highly complex development of tissues and organs is as protected as possible, the placental barrier keeps pathogens and foreign substances out. Some researchers are investigating how this protective mechanism copes with nanoparticles.

The findings are published in the journal Advanced Science.

Nanoparticles are contained in a large number of products, but they are also produced during wear and tear as well as through combustion processes. We absorb these substances from the environment via our food, cosmetics or the air we breathe.

Some of these nanoparticles are suspected of harming babies in the womb. Low birth weight, autism and respiratory diseases are among the possible consequences for the child.

It is still unclear how the nanoparticles affect the unborn child. We already know that the placental barrier retains many nanoparticles or at least delays their transport to the embryo. However, damage to the fetal tissue occurs, even if no particles have been detected in the fetus. The researchers are now getting to the bottom of this long-range effect of nanoparticles. They are investigating the consequences of common nanoparticles such as titanium dioxide or diesel soot on the function of the placenta and their indirect damage to embryonic development.

For this purpose, the team used fully functional human placentas that were made available after planned cesarean sections. Human placental tissue is the only way to obtain meaningful results on the transport and effect of nanoparticles. The structure, metabolism and interaction of maternal and fetal tissue are unique and species-specific.

Part 1

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 6:43am

The first example of cellular origami discovered in protist

Combining a deep curiosity and "recreational biology,"  researchers have discovered how a simple cell produces remarkably complex behavior, all without a nervous system. It's origami, they say.

It is a  single teardrop-shaped cell that swims in a droplet of pond water. In an instant, a long, thin "neck" projects out from the bulbous lower end. And it keeps going. And going. Then, just as quickly, the neck retracts back, as if nothing had happened.

In seconds, a cell that was just 40 microns tip-to-tail sprouted a neck that extended 1,500 microns or more out into the world. It is the equivalent of a 6-foot human projecting its head more than 200 feet. All from a cell without a nervous system. All this is because of origami!

Eliott Flaum et al, Curved crease origami and topological singularities enable hyperextensibility of L. olor, Science (2024). DOI: 10.1126/science.adk5511. www.science.org/doi/10.1126/science.adk5511

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 6:29am

Earlier experiments indicated that orexin cells are profoundly silenced by glucose, but that was 'in a dish,' in the experiments in isolated orexin cells. It since transpired that, in the living brain of a behaving mammal, orexin cells are profoundly controlled by many other things, including direct neural inputs from much of the brain.
The concentration of glucose in the blood is not only controlled by eating and exercising, it is known to also be regulated by the naturally occurring hormone insulin and the liver, which produce dynamic waves of blood glucose. Researchers used their sensors introduced in arteries to monitor these wave-like changes in glucose concentration over time.
This allowed them to note at what point in the waves (i.e., at their crest, trough, rise, fall) orexin neurons in the mouse brain became excited or fell silent. In addition, the researchers observed the behavior of the mice, particularly their spontaneous running, to determine whether it was influenced by blood glucose in normal mice and in mice that did not have orexin-producing neurons.
They found that the biggest modulation of orexin cell activity happened during the rise and fall of blood glucose waves. Surprisingly, orexin cells appeared almost blind to absolute levels of blood glucose, but mostly tracked the rises and falls, especially the rate-of-change of glucose during these rises and falls.
The findings gathered by the researchers highlight the potential role of orexin cells in tracking blood glucose levels, particularly their temporal features (i.e., their changes over time). They thus shed new light on the complex neurobiology of blood glucose perception in the brain.

Paulius Viskaitis et al, Orexin neurons track temporal features of blood glucose in behaving mice, Nature Neuroscience (2024). DOI: 10.1038/s41593-024-01648-w

Part 2

Comment by Dr. Krishna Kumari Challa on June 7, 2024 at 6:25am

Study shows orexin neurons can track how fast blood glucose changes
The concentration of glucose in the blood of humans continuously changes in response to what they eat and the activities they engage in. While many studies have investigated changes in blood glucose, the role of different neurons in tracking and predicting these changes remains poorly understood.
Researchers recently carried out a study investigating the potential role of a specific type of neuron, called orexin neurons, in tracking blood glucose levels. Their findings, published in Nature Neuroscience, suggest that orexin neurons in the mouse brain are responsible for tracking how fast blood glucose levels are changing.

In the 2000s, a lot of scientific effort went into identifying the so-called 'glucose-sensing neurons,' since these cells may alter our brain function based on what is happening minute-to-minute inside our body. With the huge 'diabesity [diabetes + obesity] epidemic' happening in some countries this was also important because sugar was implicated. Between 2005 and 2011, Burdakov's research lab contributed to the identification and characterization of glucose-sensing in orexin neurons. These are specialized neurons that have been found to sense glucose and produce the neurotransmitter orexin/hypocretin.
Orexin/hypocretin is a chemical "messenger" that contributes to the regulation of various physiological processes, including arousal, wakefulness and appetite. Orexin-producing neurons, identified about three decades ago, are only found in the hypothalamus, yet they innervate the entire central nervous system in humans and other mammals.
Orexin neurons are so important for our arousal and consciousness that without this small cluster of cells our normal consciousness is lost (as in narcolepsy—which is a disorder caused by loss of orexin cells or orexin in humans)
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