| Young girls and aged liver |
Looking back at that time, the situation was desperate and desperate. A 19-year-old Turkish girl with liver disease is in desperate need of an organ transplant. While she was waiting in line for surgery, she developed hepatic encephalopathy again. As her liver failed, toxins built up in her blood and started attacking her brain.
It didn't take long for her liver to stop working completely, and doctors immediately rescued her.
Time ticked by, and the doctors' only option was to transplant her a liver that was rejected by other hospitals. This liver is in poor shape, not only because of a cyst caused by a parasitic infection on it, but also because the organ donor is a 93-year-old woman who died not long ago. By organ transplant standards, the liver was very old, especially for such a young recipient.
However, because there were no other livers available and no other treatment options, doctors had to transplant the girl. In 2008, doctors performed organ transplants on girls at the Inonu University Liver Transplant Institute in Malatya, Turkey. The operation was a great success, and the girl not only survived, but gave birth to a healthy baby girl six years later. On her daughter's first birthday, the 26-year-old celebrated her liver's 100th birthday.
Few people know what it's like to have a liver the same age as their great-grandfather. Surprisingly, while some organs age rapidly, others can outlive us. The age of our organs and tissues is a better indicator of the actual age of our bodies than counting the number of birthdays passed.
One of the interesting things about longevity research is that your actual age doesn't seem to matter as much as you might think. In fact, researchers are more interested in the difference between chronological age and biological age. The former refers to how many years you have lived, while the latter is used to describe how our bodies age as we age.
The two ages may be closely related, but intuitively, the two do not always match. We all know that poor diet and lack of sleep can cause us to age prematurely.
| Organs and Biological Age |
We usually think of aging as a gradual process that happens all over the body, but different people age at different rates. While it’s helpful to look at how we age as a whole, it doesn’t give us the full picture. Research shows that the combined effect of genetics, lifestyle and environmental factors determines how quickly we age, but this complex effect affects each organ to the same extent.
A study of adults found that while we may have the youthful appearance of 38, our kidneys may have shrunk to look like 61. In the same way, we may be wrinkled and hair falling out like an 80-year-old, but our hearts may still be beating as hard as they were in our 40s.
Stanford geneticist Michael Snyder likens the human body to a car. "Over time, the overall performance of a car degrades, but some parts wear out faster than others," he said. "If the engine can still run, we can repair the worn parts. And so on, the human body. When an organ wears out, you can repair it."
The age of our organs and tissues is a better indicator of the actual age of our bodies than counting the number of birthdays passed.
That said, while aggregate biological age is useful to us, if we want to live longer and healthier lives, we need to understand that different body parts age differently.
However, it is not easy to accurately determine the biological age of an organ. Although there are calculators on many websites that can help people estimate the age of various organs, in order to accurately determine the biological age of an organ, it is still necessary to carry out precise inspections of organ function, tissue structure, cell composition, genetic health, etc.
Organ transplant data does offer some interesting clues about which organs become more functional with age. The researchers analyzed the relationship between donor age and recipient survival time after surgery. They found that, overall, transplants of older organs had lower success rates. However, the results of the study showed significant differences between the various organs, suggesting that some organs are more resistant to aging.
Although heart and pancreas transplant success rates decrease after age 40, the researchers found that age did not affect lung transplant success rates if the donor was under 65. The cornea is the most resistant organ, and the age of the donor has little effect on corneal transplantation.
Researchers from the University of Liverpool in the United Kingdom pointed out that the structure of organs is relatively complex, and the function of organs depends on blood vessels. These two points may be the key factors affecting the aging of organs. "It is logical to think that age-related changes in organ vasculature and microvasculature are important contributors to age-related dysfunction in organs," they wrote in their paper.
Regarding the longevity of specific organs Whether there is an upper limit, the data on organ transplants also raises many questions. Take the liver, which is known to have regenerative abilities. In patients who have surgically removed two-thirds of their livers, their livers can almost return to their original size within a year after surgery. Based on successful cases in recent years, some researchers believe that the elderly in the 90s are an untapped potential liver donor resource. In addition, researchers are closely monitoring a carefully screened group of transplant patients. The livers of these patients are over 100 years old, decades older than the patients themselves.
Some organs are more sensitive to certain aspects of our way of life. Richard Theo, director of ageing research at King's College London, said: "The lungs and pollution are prime examples. The lungs age more deeply in urban or polluted environments."
According to Theo, many elements of life can have an impact on our complex patterns of aging. "What we eat, how we eat, how we sleep, when we sleep, all these elements can affect our organs, but in different ways that we don't fully understand," he said.
The concept of organ age It's more complicated at the micro level. The individual cells that make up most of our organs wear out and need to be replaced on a regular basis, which means that many tissues regenerate thoroughly over time, just at very different rates. Red blood cells circulate in the veins and arteries for an average of four months, while the cells crawling around in the intestines are replaced after a few days. Most brain cells, or neurons, are at the other extreme. They don't renew with age, which means they're usually the same age as our bodies.
In 2019, a team led by Martin Hetzer of the Salk Institute for Biological Studies was surprised to discover that neurons are by no means the only long-lived cells in mammals. The team found cells of the same age in the liver and pancreas of experimental mice, and they coexisted with younger cells, showing an "age mosaic" state. Long-lived cells are more likely to wear out with age than cells that live for a few days, so long-lived cells that survive outside the brain could provide researchers with clues to the mechanisms of aging in other similar organs.
| Personalized Aging |
No matter how resilient our organs are in the face of aging, their function declines over time, yet research shows we can predict which organs will age first.
In 2020, Michael Snyder's Stanford University research team found that there are at least 87 molecules and microorganisms in the human body that can be used as biomarkers of aging. The team checked volunteers quarterly for two years. By studying changes in biomarkers in volunteers, they found that people appear to age through different biological mechanisms. In addition, they found that people could be grouped into different "age types" based on biomarker categories, which are based on which organ or system they are most closely associated with.
Red blood cells circulate in the veins and arteries for an average of four months, while the cells crawling around in the intestines are replaced after a few days.
Based on the dominant aging pathways, the research team found evidence for four types of aging, namely renal aging, liver aging, metabolic aging, and immunosenescence, but they believe there are others, such as cardiac aging. Snyder said the age type of people depends on a combination of genetic and environmental factors. Remarkably, the team was able to determine the age type of people long before they reached old age. If their findings are correct, young people could one day know where to focus on their health as they age.
"If you're cardiac aging, pay close attention to your LDL cholesterol, check your heart, exercise," Snyder said. "If you are metabolically aging, pay attention to your diet. If you are liver aging, pay attention to your diet." Drink less alcohol."
Critics pointed out that the age type was identified by the Stanford team in a short-term study, and we don't yet know whether the age type actually causes physiological changes that can have long-term negative effects on human health. However, Snyder firmly believes that we are entering an era of more personalized approaches to anti-aging interventions. "A 'one size fits all' approach doesn't work," he said. "Exercise and healthy eating are good for the whole body, but if your heart or kidneys are wearing down, you may need a more direct strategy."
| Reverse the aging clock |
Recent advances in the field of machine learning have allowed scientists to more precisely determine the biological process of aging, one of which is by studying semi-permanent changes in our DNA called methylation. During methylation, methyl groups are attached to parts of DNA that turn different genes on or off. The methylation process is thought to be one of several epigenetic variations in DNA that determine how our genes are influenced by our lifestyle and environment. The amount of methylated DNA changes as we age, and so does our epigenetic pattern. Biologists have thus been able to outline an "epigenetic clock," which they believe is a powerful tool for predicting the biological progression of aging.
The number of transplant patients with livers over 100 years old is increasing.
Epigenetic clocks also allow researchers to compare the biological age of different tissues. For example, there is evidence that women's breast tissue ages faster than other parts of the body, raising curiosity about whether epigenetic clocks could be used to predict breast cancer. But some scientists say that even if the epigenetic clock can accurately predict breast cancer, we don't know whether treatments that slow the clock will slow the aging process.
No matter how we think about aging, for many who study longevity, the ultimate goal is not to turn the epigenetic clock slower, but to actually turn it back. This seems to be possible at the cellular level. In March 2020, researchers at the Stanford University School of Medicine said they had extracted cells from the elderly and successfully restored their youthful vitality by inducing the cells to express Yamanaka factors. Yamanaka factor is a protein that has previously been shown to restore cells to an embryonic state. After several days of experiments, the extracted cells were years younger.
Applying these procedures to whole organs may be more challenging, but research at Stanford University School of Medicine is a first step toward developing new treatments. The new therapy is expected to reverse the circadian clock of cells and tissues in the body without removing them from the body.
For now, however, many scientists are still focusing on extending the healthy lifespan of older adults. Linda Partridge and colleagues at University College London emphasized in their review article that while drugs such as rapamycin, metformin and lithium are expected to delay the onset of age-related diseases, it should be noted that these No intervention has been able to reverse the symptoms of aging. Other researchers believe that antiaging treatments may have "tissue-specific" effects, stressing that scientists need to understand how the aging process affects different organs in different ways.
Although each organ ages in vastly different ways, it makes sense to take good care of each organ. Richard Theo emphasizes that organ systems are still interconnected, and aging in one system is destined to affect others. "If your joints are inflamed, the
inflammation also affects your brain and your heart," Theo said. "Different organs have different trajectories of ageing, but all ageing trajectories are interconnected. " : Magna
.jpeg)