Two of the researchers and several study participants with Laron syndrome
Jaime Guevara-Aguirre and Bartel Longo
People with rare genetic mutations that cause short stature and may even live longer are helping to understand the causes of aging.
People with unusual genetic mutations have some characteristics that protect them from heart disease, one of the most common causes of death, and this explains why their life expectancy exceeds that of the general population. You may have.
A signaling molecule called insulin-like growth factor-1 (IGF-1) has long been suspected to be involved in longevity. Several animals, including worms and mice, have been shown to live longer when their levels of this compound are artificially lowered, such as through genetic modification. Centenarians also have slightly lower IGF-1 levels,on average.
In most species, IGF-1 promotes growth when the animal is young and influences how cells use energy later in life. One idea is that there is a trade-off between animals investing energy in further growth and maintaining health.
“As you get older and your body starts to break down, you want to spend your energy on preventing your body from breaking down instead of spending it on growth,” he says. Nir Barzilai from the Albert Einstein College of Medicine in New York was not involved in the new study.
The question of whether this trade-off also occurs in humans is through a rare genetic disease called Laron syndrome, first identified in a group of Ecuadorians whose ancestors left Spain during the Inquisition centuries ago. can be researched.
This mutation causes people to have defective growth hormone receptors, leading to short stature. People with Laron syndrome also have low levels of IGF-1 because the release of IGF-1 is usually triggered by growth hormone.
Because so few people carry the mutation, it is unclear whether it truly extends lifespan. Suggestive evidence comes from a 2011 study of 90 Ecuadorians with Lalon syndromean estimated 400 to 500 people are affected worldwide.
The researchers found that more people with the disease were surviving longer than expected compared to the general Ecuadorian population. 'We know they are more common in older people' walter longo at the University of Southern California in Los Angeles.
In the latest study, Longo and his colleagues compared 24 people with Laron syndrome from Ecuador or the United States to 27 relatives who did not have the mutation. People with Laron syndrome appeared to be healthier on several heart-related measures, including blood pressure, blood sugar levels, and sensitivity to insulin, a hormone involved in controlling blood sugar levels.
People with this mutation also had higher levels of a compound called low-density lipoprotein. Low-density lipoproteins are also known as “bad cholesterol” because they are thought to make arteries more susceptible to plaque, which can lead to heart attacks. However, only 7 percent of Laron syndrome patients had such plaques, compared with 36 percent of their relatives.
The small number of people in the study means this difference may have arisen by chance, but it does suggest that their arteries appear less unhealthy than those of people without the mutation. suggests, Longo said.
It has also previously been shown that people with Laron syndrome are less likely to develop cancer and may have a lower incidence of cancer. Decline in cognitive function that usually occurs with older age.
This new finding supports the idea that somehow weakening the IGF-1 signaling pathway in later life can slow the aging process. Alexey Maklakov at the University of East Anglia, Norwich, UK. “It's a matter of timing,” he says. “At critical stages of growth and development, you definitely don't want to do that. But later in life, it can interfere with the function of these pathways.”
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Source: www.newscientist.com
