(Press-News.org) Tendons are what connect muscles to bones. They are relatively thin but have to withstand enormous forces. Tendons need a certain elasticity to absorb high loads, such as mechanical shock, without tearing. In sports involving sprinting and jumping, however, stiff tendons are an advantage because they transmit the forces that unfold in the muscles more directly to the bones. Appropriate training helps to achieve an optimal stiffening of the tendons.
Researchers from ETH Zurich and the University of Zurich, working at Balgrist University Hospital in Zurich, have now deciphered how the cells of the tendons perceive mechanical stress and how they are able to adapt the tendons to the demands of the body. Their findings have just been published in the journal Nature Biomedical Engineering [https://doi.org/10.1038/s41551-021-00716-x].
At the core of the newly discovered mechanism is a molecular force sensor in the tendon cells consisting of an ion channel protein. This sensor detects when the collagen fibres, that make up the tendons, shift against each other lengthwise. If such a strong shear movement occurs, the sensor allows calcium ions to flow into the tendon cells. This promotes the production of certain enzymes that link the collagen fibres together. As a result, the tendons lose elasticity and become stiffer and stronger.
Gene variant overreacts
Interestingly, the ion channel protein responsible for this occurs in different genetic variants in humans. A few years ago, other scientists found that a particular variant called E756del is clustered in individuals of West African ancestry. At that time, the importance of this protein for tendon stiffness was not yet known. One-third of individuals of African descent carry this gene variant, while it is rare in other populations. This gene variant protects its carriers from severe cases of the tropical disease malaria. Scientists assume that the variant was able to prevail in this population because of this advantage.
The researchers led by Jess Snedeker, Professor of Orthopaedic Biomechanics at ETH Zurich and the University of Zurich, have now shown that mice carrying this gene variant have stiffer tendons. They believe that tendons "overshoot" in their adaptive response to exercise due to this variant.
Major performance advantage
This also has direct effects on people's ability to jump, as the scientists showed in a study with 65 African American volunteers. Of the participants, 22 carried the E756del variant of the gene, while the remaining 43 did not. To account for various factors that influence a person's ability to jump (including physique, training, and general fitness), the researchers compared the performance during a slow and a fast jump. Tendons play only a minor role during slow jumping manoeuvres but are particularly important during fast jumps. With their study design, the scientists could isolate the effect of the gene variant on the jumping performance.
This showed that carriers of variant E756del performed 13 percent better on average. "It's fascinating that a gene variant, which is positively selected due to an anti-malaria effect, at the same time is associated with better athletic abilities. We certainly did not expect to find this when we started the project," says Fabian Passini, doctoral student in Snedeker's group and first author of the study. It may well be that this gene variant explains in part why athletes hailing from countries with a high E756del frequency excel in world-class sports competitions, including sprinting, long-jumping and basketball. To date, there has been no scientific investigation into whether this gene variant is overrepresented among elite athletes. However, such a study would be of scientific interest, Passini says.
The findings about the force sensor and the mechanism by which tendons can adapt to physical demands are also important for physiotherapy. "We now have a better understanding of how tendons work. This should also help us treat tendon injuries better in future," Snedeker says. In the medium term, it may also be possible to develop drugs that dock onto the newly discovered tendon force sensor. These could one day help to heal tendinopathies and other connective tissue disorders.
INFORMATION:
Reference
Passini FS, Jaeger PK, Saab AS, Hanlon S, Chittim NA, Arlt MJ, Ferrari KD, Haenni D, Caprara S, Bollhalder M, Niederöst B, Horvath AN, Götschi T, Ma S, Passini-Tall B, Fucentese SF, Blache U, Silván U, Weber B, Silbernagel KG, Snedeker JG: Shear-stress sensing by PIEZO1 regulates tendon stiffness in rodents and influences jumping performance in humans Nature Biomedical Engineering 2021, doi: 10.1038/s41551-021-00716-x [https://doi.org/10.1038/s41551-021-00716-x]
ANN ARBOR, Mich. - Newborns who experience seizures after birth are at risk of developing long term chronic conditions, such as developmental delays, cerebral palsy or epilepsy.
Which is why all of these babies receive medication to treat the electrical brain disturbances right away.
While some babies only receive antiseizure medicine for a few days at the hospital, others are sent home with antiseizure medicine for months longer out of concern that seizures may reoccur.
But according to a new multicenter study, continuing this treatment after the neonatal seizures stop may not be necessary.
Babies who stayed on antiseizure medications after going home weren't any less likely to develop epilepsy or to have developmental delays than those ...
A new study by University of Liverpool ecologists warns that heat-induced male infertility will see some species succumb to the effects of climate change earlier than thought.
Currently, scientists are trying to predict where species will be lost due to climate change so they can plan effective conservation strategies. However, research on temperature tolerance has generally focused on the temperatures that are lethal to organisms, rather than the temperatures at which organisms can no longer breed.
Published in Nature Climate Change, the study of 43 fruit fly (Drosophila) species showed that in almost half of the species, males became sterile at lower than lethal temperatures. Importantly, the worldwide distribution ...
When a single gene in a cell is turned on or off, its resulting presence or absence can affect the function and survival of the cell. In a new study appearing May 24 in Nature Neuroscience, UCSF researchers have successfully catalogued this effect in the human neuron by separately toggling each of the 20,000 genes in the human genome.
In doing so, they've created a technique that can be employed for many different cell types, as well as a database where other researchers using the new technique can contribute similar knowledge, creating a picture of gene function in disease across the entire spectrum of human cells.
"This is the key next step in uncovering the mechanisms behind disease genes," said Martin Kampmann, PhD, associate professor, Institute ...
New research from Florida State University shows that concentrations of the toxic element mercury in rivers and fjords connected to the Greenland Ice Sheet are comparable to rivers in industrial China, an unexpected finding that is raising questions about the effects of glacial melting in an area that is a major exporter of seafood.
"There are surprisingly high levels of mercury in the glacier meltwaters we sampled in southwest Greenland," said FSU postdoctoral fellow Jon Hawkings. "And that's leading us to look now at a whole host of other questions such as how that mercury could potentially get into the food chain."
The study was published today in Nature Geoscience.
Initially, researchers sampled waters from three different ...
TALLAHASSEE, Fla. -- New research shows that concentrations of the toxic element mercury in rivers and fjords connected to the Greenland Ice Sheet are comparable to rivers in industrial China, an unexpected finding that is raising questions about the effects of glacial melting in an area that is a major exporter of seafood.
"There are surprisingly high levels of mercury in the glacier meltwaters we sampled in southwest Greenland," said Jon Hawkings, a postdoctoral researcher at Florida State University and and the German Research Centre for Geosciences. ...
Plants grown in soil are colonized by diverse microbes collectively known as the plant microbiota, which is essential for optimal plant growth in nature and protects the plant host from the harmful effects of pathogenic microorganisms and insects. However, in the face of an advanced plant immune system that has evolved to recognize microbial associated-molecular patterns (MAMPs) - conserved molecules within a microbial class - and mount an immune response, it is unknown how soil-dwelling microbes are able to colonize plant roots. Now, MPIPZ researchers led by Paul Schulze-Lefert, and researchers from the University of Carolina led by Jeffery L. Dangl show, in two separate studies, that a subset ...
Brain tumor cells with a certain common mutation reprogram invading immune cells. This leads to the paralysis of the body's immune defense against the tumor in the brain. Researchers from Heidelberg, Mannheim, and Freiburg discovered this mechanism and at the same time identified a way of reactivating the paralyzed immune system to fight the tumor. These results confirm that therapeutic vaccines or immunotherapies are more effective against brain tumors if active substances are simultaneously used to promote the suppressed immune system.
Diffuse gliomas are usually incurable brain tumors that spread in the brain and are difficult to completely remove by surgery. Chemotherapy and radiotherapy often only have a limited ...
Scientists and clinicians at UCL and Great Ormond Street Hospital (GOSH) studying the effectiveness of CAR T-cell therapies in children with leukaemia, have discovered a small sub-set of T-cells that are likely to play a key role in whether the treatment is successful.
Researchers say 'stem cell memory T-cells' appear critical in both destroying the cancer at the outset and for long term immune surveillance and exploiting this quality could improve the design and performance of CAR T therapies.
Explaining the study, published in Nature Cancer, lead author Dr Luca Biasco (UCL Great Ormond Street Institute of Child Health), said: "During clinical trials we have seen some very encouraging results in young patients with leukaemia, however it's still not clear why CAR T-cells continue ...
A population of bridled nailtail wallabies in Queensland has been brought back from the brink of extinction after conservation scientists led by UNSW Sydney successfully trialled an intervention technique never before used on land-based mammals.
Using a method known as 'headstarting', the researchers rounded up bridled nailtail wallabies under a certain size and placed them within a protected area where they could live until adulthood without the threat of their main predators - feral cats - before being released back into the wild.
In an article published today in Current Biology, the scientists describe how they decided on the strategy to protect only the juvenile wallabies from feral cats in Avocet Nature Refuge, ...
Knowledge systems outside of those sanctioned by Western universities have often been marginalised or simply not engaged with in many science disciplines, but there are multiple examples where Western scientists have claimed discoveries for knowledge that resident experts already knew and shared. This demonstrates not a lack of knowledge itself but rather that, for many scientists raised in Western society, little education concerning histories of systemic oppression has been by design. Western scientific knowledge has also been used to justify social and environmental control, including dispossessing colonised people of their ...
