Suddenly, water is becoming more common in the solar system, and perhaps the universe, than we thought. Large deposits of nearly pure water-ice have now been suggested by new images taken by Nasa’s Mars Reconnaissance Orbiter. Last week’s discovery of water in the topsoil of the Moon triggered a renewed interest in the Earth’s satellite.

Who would have thought it? The quest for eternal life, or at least prolonged youthfulness, has now migrated from the outer fringes of alternative medicine to the halls of Harvard Medical School.

At a conference on aging held in Boston last week, the medical school’s dean, Jeffrey Flier, was to be seen greeting participants who ranged from members of the 120 club (they intend to live at least that long) to devotees of very low calorie diets.

The heavyweight at the conference was Sirtris Pharmaceu-ticals. The company is developing drugs that mimic resveratrol, a chemical found in some red wines. Resveratrol has been found to activate proteins called sirtuins, from which the company derives its name. Activation of sirtuins is thought to help the body ride out famines.

Mice and rats put on a diet with 30 per cent fewer calories can live up to 40 per cent longer. They seem to do so by avoiding the usual degenerative diseases of aging and so gain not just longer life but more time in good health. Sirtris’s researchers think that drugs that activate sirtuins mimic this process, strengthening the body’s resistance to the diseases of aging.

In mice, sirtuin activators are effective against lung and colon cancer, melanoma, lymphoma, Type 2 diabetes, cardiovascular disease and Alzheimer’s disease, said David Sinclair, a Harvard Medical School researcher and co-founder of Sirtris. The drugs reduce inflammation, and if they have the same effects in people, could help combat many diseases that have an inflammatory component, like irritable bowel syndrome and glaucoma.

Any sirtuin activator that averted all these diseases in people would be a rather remarkable drug. So there is considerable interest in how well Sirtris’s drug trials are going. Sirtris’s senior director of corporate development, Brian Gallagher, said at the conference that four active clinical trials were under way.

SRT-501, the company’s special formulation of resveratrol, is being tested against two cancers, multiple myeloma and colon cancer that has spread to the liver. A chemical mimic of resveratrol, known as SRT-2104, is in a Phase 2 or efficacy trial for Type 2 diabetes, and in a Phase 1 or safety trial in elderly patients.

Gallagher said that unpublished tests in mice showed that another chemical mimic, SRT-1720, increased both health and lifespan: after two years, twice as many mice taking the drug were alive compared with the undosed animals. Resveratrol itself has not been shown to increase lifespan in normal mice, although it does so in obese mice, laboratory roundworms and flies.

Sirtris has so far been doubly fortunate. No severe side effects have yet emerged from the clinical trials. Besides the sirtuins, several other proteins are now known to influence longevity, energy use and the response to caloric restriction. These include the receptors for insulin and for another hormone called IGF-1, and a protein of increasing interest called TOR (“target of rapamycin”). Rapamycin is an antimicrobial that was recently found to extend lifespan significantly, even when given to mice at an advanced age. Since TOR is involved in the response to caloric restriction, rapamycin may extend life through this pathway.

Sirtuins may not be the most important genes for longevity, Sinclair conceded at the conference, because the pathways controlled by the sirtuins, TOR and the others “all talk to each other, often by feedback loops.”

Many theories of aging attribute senescence to the inexorable buildup of mutations in a person’s DNA. Sinclair said that in his view “aging can be reversed” because the DNA mutations did not directly cause aging. Rather, they induce the sirtuin molecules that help control the genome to divert to the site of damage. With the sirtuins absent from their usual post, genes are not regulated efficiently, and the cells’ performance degrades. Diversion of the sirtuins should be a reversible process, in Sinclair’s view, unlike DNA damage, which is not.

“In five or six or seven years,” said Christoph Westphal, Sirtris’s other co-founder, “there will be drugs that prolong longevity.” Sirtris’s quest for longevity drugs is founded on promising research. But most drugs fail at some stage during trials. So there is no guarantee that any of Sirtris’s candidate compounds will work in people. But it is a pleasant thought that, just possibly, a single drug might combat every degenerative disease in the world.

—International Herald Tribune