Some of the world’s richest men, including Google co-founder Larry Page, Mark Zuckerberg, Oracle owner Larry Ellison and many others, seem to be mulling over the same thing: how can human life be extended through new developments in biomedical research, genetic engineering and so on. While genuinely effective anti-aging medicines are still beyond the grasp of humans, scientists have recently managed to increase the lifespan of mice by an impressive 35-percent, via a simple process of eliminating senescent cells.
Senescence refers to the gradual, yet steady, deterioration of the body’s vital components and functions, and usually starts at the cellular level with normal diploid cells losing their ability to divide. Extensive accumulation of senescent or worn-out cells has been found to negatively affect an individual’s health as well as lifespan, often causing a variety of age-related diseases, including diabetes, heart and kidney failure, tumor formation, cataract and others.
According to the researchers, removal of these defunct cells actually helped preserve normal tissue and organ functions in the rodents, raising their lifespan without any kind of adverse effect. Published in the Nature journal day before yesterday, the study was conducted by a team of scientists from Minnesota-based Mayo Clinic College of Medicine. Speaking about the findings, Darren Baker, a molecular biologist by profession and the paper’s first author, said:
It’s not just that we’re making these mice live longer; they actually stay healthier longer too. That’s important, because if you were going to equate this to people, well, you don’t want to just extend the years of life that people are miserable or hospitalized.
The study is based on a 2011 research that focused on clearing senescent cells in mice suffering from premature aging. In case of humans, these cells start appearing as we grow older, in all sorts of places, such as our skin, organs and even muscles. While the exact reason behind the phenomenon is not yet clearly understood, scientists believe that it might be the body’s mechanism to lower the risk of developing cancer. Jan van Deursen, head of the clinic’s Molecular Biology and Biochemistry department, said:
Cellular senescence is a biological mechanism that functions as an ’emergency brake’ used by damaged cells to stop dividing. While halting cell division of these cells is important for cancer prevention, it has been theorized that once the ’emergency brake’ has been pulled, these cells are no longer necessary.
When we are young, the immune system removes these defunct cells regularly; an ability that is gradually lost as we age. Accumulation of the worn-out cells in turn affects our health, damaging normal cells and also causing chronic inflammation in tissues and muscles. For the research, the scientists genetically programmed the mice to produce a special cell-killing protein, known as caspase. The protein, as the team points out, attacks another protein, called p16, that is generated by the senescent cells.
The protein is synthesized only when a specially-developed drug, called AP20187, is injected into the mice. The team administered the drug twice a week in rodents aged 12 months, which is equivalent to around 40 years in humans. According to the team, the treatment helped delay the onset of senescene, extending the animals’ lifespan by 17 to about 35-percent. In general, they were found to be healthier than the untreated controls, and showed less signs of inflammation.
The researchers are currently trying to solve some of the issues that arose during the treatment. For instance, the drug failed to eliminate the senescent cells entirely, especially those inside the liver and the colon. Furthermore, the animals undergoing treatment were found to have reduced wound healing capacity, as compared to the controls. Nevertheless, the scientists believe that the study could one day bring about great improvements in human life. Baker added:
The advantage of targeting senescent cells is that clearance of just 60 to 70 percent can have significant therapeutic effects. If translatable, because senescent cells do not proliferate rapidly, a drug could efficiently and quickly eliminate enough of them to have profound impacts on healthspan and lifespan.
The team has already started working with an American company, known as Unity Biotechnology, with the hopes that the research would eventually help develop safe and effective anti-aging medicines for humans.
Source: Mayo Clinic