Wednesday, July 27, 2016

Do Easter Island's statues hold the secrets of the fountain of youth?

It’s been nearly 50 years since scientists first discovered the natural drug hiding within the soil at Easter Island, and now, it’s been hailed by some as the ‘fountain of youth.’

The drug - rapamycin - is a bacterial by-product found in the shadows of the island's famous statues, and has shown to increase lifespan or improve some of the conditions related to aging. These ‘anti-aging’ capabilities have been demonstrated across a range of organisms, from fruit flies and mice, to dogs and even humans.

Rapamycin is named after Rapa Nui, the Polynesian name for Easter Island, which sits isolated in the Pacific Ocean. The soil containing rapamycin was first collected in 1964 by Georges Nógrády, a microbiologist from the University of Montreal. But, this wasn’t the object of the expedition, so the compound itself wasn’t discovered until five years later when the samples were analyzed by scientists at Ayerst Pharmaceutical, Chemical & Engineering News reports.

In 1969, these researchers discovered the powerful immunosuppressant which targets a protein called mTOR, a ‘central hub for nutrient signalling,’ and can stop cancer cells from dividing. Since then, scientists have unravelled far more information on the drug, finding it could help to fight solid tumors, and can prevent organ rejection in transplant patients.

The compound, which binds the proteins FKBP12 and mTOR, blocks the activity of mTORC1, which coordinates nutrient information, according to C&EN.

Later studies on yeast, nematode worms, and fruit flies determined that suppressing the activity of mTOR extended lifespan.

And in a 2009 study, it was found that administering rapamycin to fully grown mice led longer lives in both males and females – an extra six months for male mice, 9% longer than those without the drug, and 14% longer in females.

The drug has since been tested on marmosets, and even humans.

These trials have yielded some positive results, showing improvements in certain aspects of aging, including learning and cognitive function in humans, along with response to the flu vaccine, and proteostasis in marmosets, the maintenance of proteins.

Recently, it was revealed that scientists from the University of Washington are testing the effects of rapamycin on dogs to see if it will slow down the aging process. Researchers were shocked by results of the initial trials, which were revealed this past May, finding that some dogs showed improved heart functionality after just a few weeks.

The study is led by biologist Matt Kaeberlein and his colleague, Daniel Promislow. According to Fusion, the researchers began clinical trials this year.

Dogs age very quickly compared to a human lifespan; most live between 10 and 13 years. This allows researchers to study the entire aging process in a short amount of time.

The team recruited 40 dog-owners, who were each to give their pets three tablets of rapamycin a week, Fusion reports.

After the researchers weeded out dogs with heart conditions and other medical factors, they were left with 24 middle-aged dogs, who would each receive low doses of the drug. This continued over the course of 10 weeks, and the researchers took echocardiograms throughout to determine any changes in the animal’s heart function.

The team discovered that dogs receiving rapamycin showed improved heart functionality, or showed no change. Those who had come in with worse conditions initially saw the most improvement.

But, as research on the ‘fountain of youth’ drug continues, scientists warn that it isn’t yet clear if mTOR inhibitors are safe for long-term use. Rapamycin’s immune system-suppressing capabilities also mean it could leave its user susceptible to infection, scientists warn.

Now, many are working to develop compounds that don’t have a negative effect on the immune system.

‘It’s not optimized for what we want – which is treating disease or slowing aging,’ Brian Kennedy, president and chief executive officer of the Buck Institute for Research on Aging told C&EN, ‘but it’s pretty darn good at what it does, and if we can tweak it in ways that make it better, I think there’s a really exciting opportunity.’

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