Scientists have succeeded in re-establishing cell division in aging cells using low-frequency ultrasound. This also improved the physical performance of the aged mice.
Ultrasound, which is inaudible to humans, has been found to have rejuvenating effects. The sound waves not only restarted aging human cells, but also breathed new life into old mice. The animals performed better physically, among other things, as they showed on the treadmill. There was also an old mouse with a hunchback, who could walk normally again.
‘Is it too good to be true?’ “I often ask myself this question,” says Michael Sheetz, a biochemist at the University of Texas Medical School in the US. He and his team plan to conduct a small-scale human trial to see if the ultrasound technology is safe and can help treat age-related diseases.
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When cells multiply a certain number of times, they stop dividing. This is also called an extension Hayflick Limit named. become cells calmie: obsolete. Other factors, such as toxic chemicals, can also cause cells to age.
This can eventually lead to a domino effect: some aging cells release chemicals that cause other cells to age again. This is considered one of the main causes of aging and age-related diseases: as we age, there are more and more senescent cells in different parts of the body.
Therefore, many scientists are looking for a way to destroy senescent cells. But we probably don’t need to kill them: low-frequency ultrasound can help us regenerate these cells.
less than echo
Sheetz’s team found that low-frequency ultrasound stimulated senescent cells in monkeys and humans to divide. They also no longer secrete chemicals that promote aging. The researchers used sound waves with a frequency of 100 kilohertz, which is five times louder than what the human ear can hear, but much lower than the 2,000 kilohertz ultrasound of children.
Normally, human cells show signs of aging after about 15 cell divisions. After ultrasonic treatment, these cells reached 24 cell mitotic count without abnormal phenomena. The team is still discovering the new limit.
Exceeding the Hayflick limit can be useful when culturing cells for human therapies. Sheetz also wants to sell the ultrasound machines to other labs so they can try them, too.
In addition to human cells, the researchers have already treated whole animals. They placed rats between the ages of 22 and 25 months in warm water so that they were at least half submerged. Ultrasound loses less energy because it propagates through water, compared to air. Mice treated with ultrasound in this way performed better on physical tests than mice that were in warm water without ultrasound.
In some cases, Sheetz says, the improvements have been dramatic. One old mouse suffered from a hunchback and could not move properly. This scored the worst result in the first tests. “We treated this mouse with ultrasound, and suddenly it moved normally again. I don’t think we’re exaggerating the word rejuvenation.
The team also used a fluorescent dye that sticks to senescent cells. This allowed them to see that the percentage of these cells in the kidneys and pancreas decreased after treatment. Why ultrasound produces these effects is not clear. “Some aspects are still confusing,” Sheetz says.
Still, he has a premise. His idea is that the physical disturbance of cells by ultrasound causes an effect similar to sport or exercise. It activates waste removal systems, which are turned off in senescent cells.
Are the results convincing? “In general, yes,” says Jürgen Goetze, an aging biologist at the University of Queensland in Australia. “But I think we need to do more research to find out what the ultrasound criteria are.” It would also be difficult to apply to humans, he says, because bones and lungs block ultrasound.
Ultrasound foot baths
Götz and his team showed that rats had better memory after treatment with high-frequency ultrasound. He is also trying to see if this treatment could be used in people with Alzheimer’s disease.
Ultrasound has been used for decades to treat a variety of conditions, but mostly smaller devices and higher frequencies are used. Results vary. Since different types of equipment and different methods are used, it is difficult to say how effective they are. It’s also difficult to compare studies with one another, Gotze says.
Sheetz and his team are attending a trial in which people with osteoarthritis are immersed in water for treatment, and people with diabetic foot ulcers are treated with ultrasonic foot baths.
Therapies that stimulate cell division can also increase the risk of cancer, but according to Sheetz, there were no indications of this in his research.