New Reports Point Ways to Extend Longevity – at
Least for Naked Mole Rats and Roundworms
Naked mole rats live longer with better protein
creation; roundworms find fountain of youth in niacin (vitamin B3) that
tricks body into thinking it is exercising
Sept. 30, 2013 – It there is anything that grabs
the attention of senior citizens it is probably information about
longevity – ways to extend our lives There are two research reports out
today on success at extending life, at least when it comes to naked mole
rates and roundworms.
Naked mole rats have what any animal would want.
They live long lives - about 30 years - and stay healthy until the very
end. Now biologists at the University of Rochester have new insights
into the animal's longevity - better-constructed proteins.
Proteins are involved in nearly all functions of an
animal cell, and consequently, are essential to all organisms. But
before proteins can do their job, they must fold into the appropriate
shapes that allow them to connect to and interact with other structures
in the cell.
In a paper published this week in the
Proceedings of the National Academy of Sciences, Vera Gorbunova and
Andrei Seluanov describe their discovery of the process in naked mole
rats that leads to virtually perfect proteins.
"While this is basic research," said Gorbunova, "we
hope our findings encourage further studies on better protein
Their work focused on naked mole rat ribosomes -
the site of protein creation in the animal's cells - and began by
happenstance. The researchers were working with ribosome RNA (rRNA) when
they made a discovery. After applying a dye to a sample, they studied it
under ultraviolet light only to find three dark bands - representing
concentrations of different rRNA molecules -not the two bands that are
characteristic of all other animals, suggesting that there is a "hidden
break" in the naked mole rat rRNA.
Since rRNA is an essential part of the
protein-creation mechanism, the two biologists decided to see if the
broken rRNA affects the quality of naked mole rat proteins.
Ribosome RNA strands act as scaffolds on the
ribosome, a protein synthesis machine. Changing the shape of the
scaffold can have a profound effect on the organization of the ribosome
Gorbunova and Seluanov discovered that the naked
mole rat's rRNA scaffold is indeed unique. The rRNA strands split at two
specific locations and discard the intervening segment. Instead of
floating off on their own, the two remaining pieces from each strand
stay close to each other and act as a scaffold on which ribosomal
proteins are assembled to create a functional ribosome—a molecular
machine that puts amino acids together to create proteins. And the
results are impressive.
When the ribosome connects amino acids together to
create a protein a mistake is occasionally introduced when an incorrect
amino acid is inserted. Gorbunova and Seluanov found that the proteins
made by naked mole rat cells are up to 40 times less likely to contain
such mistakes than the proteins made by mouse cells.
"This is important because proteins with no
aberrations help the body to function more efficiently," said Seluanov.
The next step for the biologists is to split mouse
rRNA in the same way to see if it would lead to improved protein
The two biologists hope their work will eventually
result in pharmaceutical treatments that modulate protein synthesis in
humans, though any medical solution is a long way off.
Niacin, the fountain of youth for roundworms
The vitamin niacin has a life-prolonging effect, as
Michael Ristow has demonstrated in roundworms. From his study, the
ETH-Zurich professor also concludes that so-called reactive oxygen
species are healthy, not only disagreeing with the general consensus,
but also many of his peers.
would not want to live a long and healthy life? A freely available food
supplement could help in this respect, scientists from ETH Zurich have
demonstrated in roundworms. Vitamin B3 – also known as niacin – and its
metabolite nicotinamide in the worms’ diet caused them to live for about
one tenth longer than usual.
As an international team of researchers headed by
Michael Ristow, a professor of energy metabolism, has now experimentally
demonstrated, niacin and nicotinamide take effect by promoting formation
of so-called free radicals. “In roundworms, these reactive oxygen
species prolong life,” says Ristow.
“No scientific evidence for usefulness of
This might seem surprising as reactive oxygen
species are generally considered to be unhealthy. Ristow’s view also
contradicts the textbook opinion championed by many other scientists.
Reactive oxygen species are known to damage somatic cells, a condition
referred to as oxidative stress. Particular substances, so-called
antioxidants, which are also found in fruit, vegetables and certain
vegetable oils, are capable of neutralising these free radicals. Many
scientists believe that antioxidants are beneficial to health.
“The claim that intake of antioxidants, especially
in tablet form, promotes any aspect of human health lacks scientific
support,” says Ristow. He does not dispute that fruit and vegetables are
healthy. However, this may rather be caused by other compounds contained
therein, such as so-called polyphenols.
“Fruit and vegetables are
healthy, despite the fact that they contain antioxidants,” says the
ETH-Zurich professor. Based on the current and many previous findings he
is convinced that small amounts of reactive oxygen species and the
oxidative stress they trigger have a health-promoting impact. “Cells can
cope well with oxidative stress and neutralise it,” says Ristow.
Substance mimics endurance sport
In earlier studies on humans, Ristow demonstrated
that the health-enhancing effect of endurance sports is mediated via an
increased formation of reactive oxygen species – and that antioxidants
abolish this effect. Based on the present study, he concludes that
niacin brings about a similar metabolic condition to exercise.
“Niacin tricks the body into believing that it is
exercising – even when this is not the case,” says Ristow. Such
compounds are known as “exercise mimetics”.
The researchers conducted their experiments on the
model organism Caenorhabditis elegans.
This worm, which is merely one millimetre in length, can be
easily maintained and has a lifespan of only a month, making it the
ideal model organism for ageing research.
Also relevant for humans
The results of the study may also be of relevance
for humans, says Ristow. After all, the metabolic pathway initiated by
niacin is very similar in roundworms and higher organisms. Whether
niacin has similar effects on the life expectancy of mice is the subject
of Ristow’s current research. Previous studies also suggest a
health-enhancing effect of niacin in humans with elevated blood
Niacin and nicotinamide have been approved as
dietary supplements for decades. Ristow could easily envisage the
substances being used broadly for therapeutic purposes in the future. A
whole series of foods naturally contain niacin, including meat, liver,
fish, peanuts, mushrooms, rice and wheat bran. Whether nutritional
uptake is sufficient for a health-enhancing or lifespan-extending
effect, however, remains to be demonstrated, says Ristow.
Disputed impact of enzymes
The latest study on the effects of niacin and
nicotinamide is based on a particular class of enzymes, the sirtuins,
which convert niacin into nicotinamide. Moreover, they are also involved
in gene regulation, helping to down regulate the activity of certain
genes. Until today, scientists have been disputing whether sirtuins have
a life-prolonging impact.
Ristow and his team’s work now suggests that the
activity of sirtuins actually prolongs life in roundworms. According to
the study, however, the life-prolonging effect is not down to gene
regulation, as has often been supposed in the past. Instead, the effect
is due to the conversion of niacin into nicotinamide.
Studying genetically modified roundworms that were
unable to convert nicotinamide into certain other metabolic products,
the scientists did not observe any lifespan extension, even after
overexpression of sirtuins, which otherwise lead to an increased life
> Nursing Home Abuse,
> Personal Injury
Our Experienced Lawyers Can Help
"We win because we care, we prepare
and we have no fear," Beth Janicek, board certified personal