In today’s edition of far-out science, researchers have found evidence that the wafting aroma of food has an effect on an organism’s lifespan–and they’ve demonstrated that interfering with a fruit fly’s sense of smell causes it to live a longer, healthier life. While there’s no guarantee that the trick would work for humans, optimistic researchers suggest that certain odors—or drugs that block us from sensing them—might one day help prevent disease and extend lives [ScienceNOW].
In the past decade, scientists have established a clear connection between extremely low-calorie diets and extended lifespans; studies have demonstrated that yeast, fruit flies, mice, and monkeys on these diets live longer than their peers. While the exact mechanism at work isn’t yet clear, researchers suspect that a near-starvation diet causes an organism’s metabolism to slow down, and triggers other changes that evolved to help organisms survive in times when food was scarce. Now scientists say it may not be just what a creature eats, but also what it smells that has an effect on how long it lives.
In one 2007 study, molecular biologist Scott Pletcher and his colleagues found that completely eliminating fruit flies’ sense of smell caused them to live nearly 20 percent longer than normal flies. They also found that wafting the smell of yeast, a tasty treat for fruit flies, towards flies that were on a low-cal, live-extending diet hastened the death of those flies. This led the scientist to hypothesize that specific odors might be influencing the flies’ lifespans. Luckily, other scientists had identified a receptor in a group of neurons that enable fruit flies to smell carbon dioxide, which signals the presence of a good meal of tasty yeast [ScienceNOW]. So, Pletcher and his team set out to find if the CO2 had anything to do with the duration of the flies’ lives.
Louise Brown, the first baby conceived through in vitro fertilization, will be turning 32 this year, and most people born through IVF are still younger than 30. While the technique has become commonplace for would-be parents struggling with fertility problems, doctors note that the long-term effects of the procedure still aren’t certain. Now, some scientists are saying they see slight differences in the DNA expression of people born via IVF, and that it’s possible they could be at higher risk for conditions like cancer or diabetes later in life.
Says lead researcher Carmen Sapienza said “By and large these children are just fine, it’s not like they have extra arms or extra heads, but they have a small risk of undesirable outcomes” [The Guardian]. Rather, the team found a very subtle impact. In 75 IVF babies and 100 naturally conceived ones, they examined 700 genes that particularly interested the researchers because they are linked to fat cell development, insulin signaling, and other functions associated with diseases for which people tend to be at higher risk as they age. The scientists checked DNA methylation, a modification to DNA which affects gene expression, and found that 5 to 10 percent of IVF babies had abnormal patterns of methylation.
Sapienza’s team published the study in October in Human Molecular Genetics, but his work is picking up attention after he spoke at the American Association of the Advancement of Science meeting in San Diego.
Sure, Botox can banish crows feet, smooth those wrinkles, and lift those frown lines, making the client look more youthful–and somewhat expressionless. But the treatment may have effects that are more than skin deep. A new study suggests that by paralyzing the frown muscles that ordinarily are engaged when we feel angry, Botox short-circuits the emotion itself [Newsweek].
In the now-common cosmetic treatment, a doctor injects botulinum toxin, sold under the brand name Botox, under the skin. The toxin kicks in, temporarily paralyzing facial muscles, smoothing skin out, and making a person look less wrinkly as a result. That paralysis, however, seems to interfere with a known feedback loop, in which smiling adds to your happiness and frowning multiplies your sadness [LiveScience]. And tamping down a person’s emotions seems to interfere with the ability to read emotions in others. Says study leader David Havas: “Botox [also] induces a kind of mild, temporary cognitive blindness to information in the world, social information about the emotions of other people” [Discovery News].
There’s your chronological age, the number that creeps depressingly upward with each passing birthday, and then there’s your biological age, associated with the condition of your body. In a study this week in Nature Genetics, a British team discovered a link between a particular genetic variation and people being several years older in their biological age.
Says study leader Nilesh Samani: “What we studied are structures called telomeres which are parts of one’s chromosomes. Individuals are born with telomeres of certain length and in many cells telomeres shorten as the cells divide and age” [Press Association]. Some people, however, are born with shorter telomeres to begin with, which sets them up to age faster, biologically speaking, and could put them at greater risk for age-related diseases.
Researchers have long sought an answer to burning question of why women live longer on average then men (you know, other than the fact that, as Harry Belafonte puts it, “man smart, woman smarter“). Now a new study in Human Reproduction by Japanese researchers reinforces the argument that the fault lies in men’s genes, a conclusion they reached by taking males completely out of the picture.
They studied mice created with genetic material from two mothers, but no father. This was achieved by manipulating DNA in mouse eggs so the genes behaved like those in sperm [BBC News]. The scientists then implanted those sperm-behaving eggs into female mice, creating 13 “bimaternal” mice. On average, these fatherless mice lived a third longer than those conceived in the usual manner, according to study leader Tomohiro Kono.
The naked mole rat is a species with a long list of peculiarities. The mole rat is about the same size as the more hirsute wild mouse, but lives seven times as long, sometimes reaching the ripe old age of 28. The creatures almost never poke their noses beyond the snug confines of their burrows and tunnels, and instead live out their lives underground in the dark. They’re also the only mammals who have a social structure that resembles an ants’ nest or beehive, where only one dominant female mates and reproduces.
Finally–and this is the part that most interests researchers–naked mole rats never get cancer.
A new study in the Proceedings of the National Academy of Sciences probed the mole rats’ robust good health, and determined how they beat cancer. The naked mole rat’s cells hate to be crowded, it turns out, so they stop growing before they can form tumors…. Normal human and mouse cells will grow and divide in a petri dish until they mash tightly against one another in a single, dense layer–a mechanism known as “contact inhibition.” Naked mole rat cells are even more sensitive to their neighbors, the researchers found. The cells stop growing as soon as they touch [ScienceNOW Daily News]. Researchers hope that the mechanism can one day lead to novel treatments for cancer, where cancerous cells won’t stop multiplying and form tumors.
The Nobel Prize for medicine has been awarded to three U.S. researchers who probed the mechanism of cellular division, and whose work opened new avenues both in the fight against cancer and attempts to slow aging. The prize will be shared by Australia-born Elizabeth Blackburn, Carol Greider, and London-born Jack Szostak.
The three researchers solved the mystery of how chromosomes, the rod-like structures that carry DNA, protect themselves from degrading when cells divide. The Nobel citation said the laureates found the solution in the ends of the chromosomes — features called telomeres that are often compared to the plastic tips at the end of shoe laces that keep those laces from unraveling [AP].
Babies born in rich nations today have the best shot at becoming centenarians. That’s if current life expectancy trends continue, according to the study published in The Lancet.
Not only will these babies live longer, but they’ll be healthier well into old age. The researchers based their projections on a case study of Germany that showed that by 2050, its population will be substantially older and smaller than now — a situation it said was now typical of rich nations [Reuters]. In the United States, half of the babies born in 2007 are expected to live to a ripe 104 years old. The authors credited improvements in health care, medicine, and lifestyle, as well as a drop in infant mortality rates, for increased life spans.
Data from more than 30 developed countries shows that since 1950 the probability of surviving past 80 years of age has doubled for both sexes [BBC News]. However, the study cautions that despite improved life expectancies, an increase in cancer, cardiovascular disease and other chronic illnesses has risen with aging populations [ABC News]. As citizens get older and require more medical care, the increased life expectancies may place a burden on society. Already, many countries are pushing to extent the retirement age to grapple with the costs.
80beats: When Laws Save Lives: Cleaner Air Increased Life Expectancy by 5 Months
80beats: A Single Genetic Tweak Gives Mice Longer, Healthier Lives
80beats: Low-Calorie Diet Staves off Aging & Death in Monkeys
Image: flickr / Will Foster
By deleting a single gene from a mouse’s genetic makeup, researchers have created a mighty mouse with a longer, healthier life. The change mimicked the effect of keeping the mice on a calorie-restricted diet. Severely restricting the diets of yeast, bacteria, mice and primates have granted these animals unnaturally long lives. For humans, however, maintaining a diet of near starvation would be difficult at best [Discovery News]. That’s why researchers are actively pursuing drugs that could produce the same anti-aging effect.
Study coauthor Dominic Withers says the effect was striking–but for reasons not yet understood, only the female mice benefited. The mice didn’t just live longer, they also had fewer age-related ailments. “These mice were resistant to type 2 diabetes … and they also appeared to have reduced incidence of the mouse-equivalent of osteoporosis — so they had stronger bones,” Withers said. Balance, strength and coordination all improved in the [female] mice, and they were more inquisitive, suggesting their brains were healthier [Reuters].
One of Britain’s best-known orchestra conductors and his wife have ended their lives at an assisted suicide facility, reigniting the debate over assisted suicide. Helping someone die is a criminal offense in Britain, so Sir Edward Downes, 85, traveled to a “right-to-die” facility near Zurich with his 74-year-old wife, Joan, who had terminal cancer.
Under Britain’s Assisted Suicide Act, helping someone kill him- or herself can bring a penalty of up to 14 years in prison. In Switzerland, however, assisted suicide is legal; the Downeses were not the first Britons who traveled there to legally commit assisted suicide. Since the Zurich clinic run by [the non-profit group] Dignitas was established in 1998 under Swiss laws that allow clinics to provide lethal drugs, British authorities have effectively turned a blind eye to Britons who go there to die…. None of the family members and friends who have accompanied the 117 people living in Britain who have traveled to the Zurich clinic for help in ending their lives have been charged with an offense [The New York Times]. Experts say it’s unlikely that this will change in the case of the Downses’ children, who potentially assisted in their parents’ suicide by traveling with them to the Zurich facility. Still, the fact remains that the couple’s children could potentially be charged with a crime for their involvement in the suicide.