August 29, 2010

USA: Two new books show why aging - and anti-aging - science matters

WASHINGTON / The Washington Post /  Outlook & Opinions / August 29, 2010

The scientific quest to combat aging -- two books take sides

By Susan Okie

It's striking that two new books on the same subject -- science's current efforts to slow aging and lengthen the human lifespan -- view a single body of research through such different lenses.

The Strange Science of Immortality
By Jonathan Weiner
Ecco. 310 pp. $27.99

In "Long for This World," Pulitzer Prize-winning science writer Jonathan Weiner surveys the field as if from a mountaintop:

He's intrigued, yet detached and skeptical, frequently digressing from science to discuss how religions and cultures have dealt with the problem of mortality and to ponder whether humans' lust for ever-longer lives is a good thing.

In "The Youth Pill," science and business journalist David Stipp hunkers down in the trenches with researchers as they test compounds, such as resveratrol, rapamycin and their chemical cousins, that offer the hope (based mainly on animal studies) of warding off many of the ills that afflict aging bodies.

Scientists at the Brink of an
Anti-Aging Revolution
By David Stipp
Current. 308 pp. $26.95

Although no drug has been shown to extend the human lifespan, David Stipp argues that such remedies are potentially just around the corner -- and that the federal government should fund clinical trials to speed their arrival on pharmacy shelves.

Meanwhile, resveratrol, found in small amounts in red wine, is being marketed as a dietary supplement, even though no studies have established whether taking large doses over long periods is safe and effective.

Weiner usually structures his books around the work and ideas of individual scientists, and for this one he has chosen Aubrey de Grey, a brilliant but eccentric Cambridge computer scientist who has become an acknowledged leader in devising strategies to vanquish aging. As a protagonist, de Grey is unappealing: He's good at seeing the big picture, but he's described as an arrogant man who takes pleasure only in working, swilling beer and punting on the River Cam.

Weiner uses their encounters to lay out current theories about why we age. Aging is not a biological constant: Some organisms (hydras and sponges, for example) seem to be virtually immortal, while some closely related groups of animals (such as bats and mice) have dramatically different lifespans. Human aging stems from progressive damage to our cells and their DNA -- caused by threats from within, such as dangerous byproducts of metabolic reactions, and from without, such as exposure to radiation or mutagenic chemicals. It's also thought to result from inherited mutations that have persisted in our genomes because they improve our reproductive success, though they take a toll later in life.

De Grey simplifies aging to a list of the "deadly things" that eventually happen to everyone: the accumulation of junk inside and outside cells, harmful mutations, a loss of certain crucial cells and an oversupply of others, and the progressive cross-linking of molecules in connective tissue that leads to wrinkled skin, stiff tissues and organ damage. Fix those problems, he argues, and a human being could live to be 1,000.

Sound far-fetched? I agree -- yet discoveries during the past two decades suggest that some of these processes can at least be postponed. Despite his overly cheerleading tone, Stipp does a better job than Weiner of explaining this recent progress and conveying the mounting excitement of scientists in the field. His central character is David Sinclair, a brash Harvard researcher whose 2006 study of resveratrol's life-extending effects in mice ignited the interest of investors, drug companies and the public. Stipp, a former reporter for Fortune and the Wall Street Journal, also interviewed other scientists on the forefront of the search for compounds that, like resveratrol, appear to activate genes involved in animals' response to environmental stress. Some of these genes were discovered in mutant worms or fruit flies that lived unusually long; others were found by researchers exploring why restricting food intake lengthens lifespan and conserves vigor in virtually every species that's been studied.

Calorie restriction itself isn't a practical therapy: It shrinks muscles, causes fatigue and infertility, and makes people miserably hungry. But compounds that selectively activate some of the genes that are activated by calorie restriction may slow aging without these side effects. In a study sponsored by the National Institute on Aging, one such compound, rapamycin, increased the maximum lifespan of mice by around 10 percent; small trials have been conducted in people with heart disease and cancer, but rapamycin's net effect on human health is unknown.

The past two centuries have already seen a doubling of average life expectancy, with most of the progress in the past 50 years coming from improvements in the lives of older adults.

"The number of centenarians on the planet has more or less doubled with every decade since 1960," Weiner notes. Longer lifespans in developed countries are strongly associated with lower birthrates, leading to changes in population makeup and raising questions about the impact on national economies.

While Stipp suggests that anti-aging drugs could deliver a "free lunch," it seems more likely that there will be costs -- for the individual, for society, for the planet. As Weiner writes, "No other scientific program raises so many enormous and imponderable questions, and they are so blithely dismissed by the engineers who would build the dam in the valley of the shadow of death."

Susan Okie is a physician, a freelance medical journalist and a former Washington Post reporter and editor.

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