Sleepless cancer cells, muscle atrophy in astronauts and the hormonal causes of the desire to grill in summer – that’s what our news for true nerds is about today.
Breast cancer is nocturnal
What do metastatic cancer cells and owls have in common? They both like to be out and about at night! This is obviously nothing new for birds of prey, but it is for cancer cells – it was previously assumed that tumors secrete their cell offshoots continuously.
However, Swiss researchers have now come to the surprising conclusion: the circulating cells, which later metastases can grow, arise above all during the sleep phase of the affected patients. In her in Nature published study, they examined blood and tissue samples from 30 breast cancer patients, taken at different times of the day; further investigations in the mouse model supported their discovery. They found that not only did more cells leave the tumors at night – these cells also divided much faster than tumor cells that were removed during the day and therefore had a higher potential for metastasis formation.
The researchers found that the escape of cancer cells by hormones circadian rhythm how Melatonin is controlled. So you suspect that in the case of biopsies, the time of removal could influence the oncological findings. “In our view, these results suggest that healthcare professionals should systematically record the time at which they perform biopsies,” commented Study leader Prof. Nicola Aceto. “That could help make the data really comparable.”
In the next step, the researchers want to find out whether the phenomenon only occurs in breast cancer or whether other types of cancer behave in a similar way. If this is the case, the next question is also clear: Could tumor therapies be more successful if the patients are treated at different times in the future? Further research needs to show this.
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Life in space: That muscle can go, right?
One of the important functions of skeletal muscle is to maintain posture. The muscles in the neck, back and limbs must counteract gravity to enable us to stand and walk upright. But what actually happens to the muscles when there’s no more gravity to fight? For us on Earth it’s just a mind game, but for astronauts it’s an extremely relevant question.
In a comprehensive review in a special space issue by Neuroscience & Biobehavioral Reviews a Japanese research team devoted itself to this question. Obviously, the reduced stress leads to atrophy and changes in the structure and properties of the “antigravity” muscles – just like other muscles. For example, it has been observed in astronauts that the volume of the calf muscles decreases during their stay in space. The muscle wasting is due to a remodeling and decline of Sarcomere attributed.
Using simulation models, the researchers found that the afferent neuronal activity – i.e. the signals that are transmitted from the muscle to the ZNS are sent – plays a key role in regulating muscle properties and also brain activity. Not only the muscles themselves, but also the nerves are affected by a non-gravity environment. Not only does the strength of the muscles dwindle, but motor control also deteriorates; this then manifests itself in disturbed coordination and mechanics of antagonistic muscles. The result: when the astronauts return to earth after a few months of weightlessness, they have walking difficulties – despite the daily training that is part of the daily routine in the ISS space station.
Training on the treadmill and other equipment designed to compensate for the effects of reduced gravity is not always effective and, according to the Japanese, can still be improved – especially with regard to long, manned flights to Mars. For example, they recommend targeted, appropriate stimulation of the Sole muscle during running training on the ISS by stepping on the heel, as well as regular, passive stretching of the muscle.
interest aroused? then here along to the original publication.
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Grilling in summer: the hormones demand it
The same game every year: When the temperatures rise in spring and the sun dares to come out again, the barbecue tongs are pulled out. The male sex in particular does not seem to be able to resist the temptation (in the public perception), as if by magic they are lured to coal, flame and grilled food in summer. Is that really the case – and where does it come from? A new study could provide at least a rudimentary answer: More sunlight may make men hungrier.
In a study in Nature Metabolism A team of researchers from Tel Aviv University examined the data from a multi-year national nutrition survey with 3,000 participants. It was noticeable that from March to September the male subjects increased their average food intake by around 300 additional kilocalories per day – but the female subjects did not. The researchers wanted to find out more about the phenomenon and recruited ten subjects, 5 men and 5 women, for this purpose. After 25 minutes of midday sun exposure on a clear day, the blood showed an increase of Ghrelin, an appetite-stimulating hormone—again, only in men. A study in an animal model demonstrated the same phenomenon: male mice ate through food after exposure UV-B radiation more and showed increased ghrelin levels, whereas female mice did not.
In further investigations in animal and cell models, the researchers were also able to find a possible explanation for the phenomenon: UV radiation caused Adipocytes activated in the skin, leading to the release of ghrelin. Estrogen however, blocked this effect – which would explain why women are not affected.
The number of participants in the study was not too high, so further studies on the subject would be desirable. The possible health effects of this mechanism are also interesting: ghrelin also has an anti-inflammatory effect. This may help explain why moderate exposure to sunlight appears to have beneficial effects on cardiovascular health, in addition to the well-known beneficial effects of boosted exposure Vitamin D Production.
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Image source: Vincent Keiman, Unsplash