Rapamycin: Extended Lifespan, Extended Decline?

Ever since 2009, it has been known that the drug rapamycin extends the lifespan of mice.  The journal Science identified this discovery as one of the top 10 research breakthroughs for that year.  The news was all the more exciting because rapamycin already has FDA approval for other uses.

So researchers want to know just how rapamycin extends the lifespan.  Does it actually slow the entire aging process?  Or does it just slow down certain diseases, such as cancer?  

New research testing the effects of rapamycin on mice suggests that the drug probably does not slow the aging process itself.  It does slow the development of cancer and a few other diseases.  But rapamycin is no fountain of youth.  In fact, if it were used just by itself to extend the lifespan of human beings, it might merely draw out the aging process.  In other words, it might extend the lifespan but not extend the healthspan.

Photo: Public domain through Wikimedia. Thanks to Rama.

The research was conducted by a team led by Dan Ehninger and his colleagues at the German Center for Neurodegenerative Diseases. It is published in the August 2013 issue of The Journal of Clinical Investigation, which is freely available online.  In addition to the research article, the journal is publishing an expert commentary that warns about any drug that brings an increase in lifespan that “is accompanied by more disability and disease and a greater loss of physiological functions, i.e., a reduced quality of life.”  By itself, rapamycin could do just that.

On the bright side, the new study shows even more conclusively that rapamycin extends the lifespan of mice by the equivalent of almost a decade of human life.  It also provides a small benefit for cognitive function.  So despite the mixed results, the journal commentary advocates clinical trials involving human patients, perhaps those with dementia.  According to the journal article, the research supports “the feasibility of clinical trials to study the efficacy of rapamycin in treating diseases of the elderly, especially those that are debilitating and for which no current treatment is known, such as Alzheimer’s disease and other neurodegenerative diseases.”

Advocates of anti-aging research will see this new study as something of a set-back, but it is not likely to slow down basic work in the field.  Opponents of anti-aging research are likely to renew their warnings about the prospect of more years of declining health.  Any effort to enhance our humanity, whether it is by increasing cognitive ability or extending the lifespan, is always accompanied by a down-side, by side effects so costly that true enhancement is impossible.  The warning is serious, but advocates of human enhancement are not likely to be convinced.   

The research article is entitled “Rapamycin Extends Murine Lifespan but Has Limited Effects on Aging.”  The commentary is entitled “Rapamycin, Anti-aging, and Avoiding the Fate of Tithonus.”  Both are available free to the public in the August 2013 issue of The Journal of Clinical Investigation.

Did Neandertals Wear Ornaments?

A small but tantalizing find provides further evidence for Neandertal culture.  Working in the foothills of the Alps just north of Venice, Italy, researchers have discovered and analyzed a small marine shell that originally came from about 60 miles away.  It was thinly coated with a dark red substance that turns out to be pure hematite and was most likely used as a pigment.  One possibility is that the shell was used as an ornament.

The paper, freely available online in the journal PLoS One, dates the shell’s pigmentation to a period just before 45,000 years ago, right before the arrival of so-called “modern” humans in Europe. 

Photo Caption: A shell possibly "painted" by Neandertals about 45,000 years ago.  Photo available from PLoS One.

According to the paper, “deliberate transport and coloring of an exotic object, and perhaps its use as pendant, was a component of Neandertal symbolic culture, well before the earliest appearance of the anatomically modern humans in Europe.”

Quoting more of the paper, “this discovery adds to the ever-increasing evidence that Neandertals had symbolic items as part of their culture.”

Debates about Neandertal culture have intensified recently, in part because of genetic evidence of interbreeding between Neandertals and the modern humans coming into Asia and Europe.  While these modern humans began their migration out of Africa about 80,000 years ago and probably interbred around 55,000 years ago, they did not reach Europe until more like 40,000 years ago.  If all these dates hold up in future research, this shell does provide a small but intriguing hint about the culture of Neandertals at just about the time of their encounter with “modern” humans. 

So who exactly is modern?  The differences between ourselves (the humans we like to call “modern”) and the Neandertals are not as great than we once imagined.  The paper ends with these words: “Future discoveries will only add to our appreciation of Neandertals shared capacities with us.”

The paper, entitled "An Ochered Fossil Marine Shell From the Mousterian of FumaneCave, Italy," appears in the current issue of PLoS One and is freely available online.

The Rise of Agriculture: New Findings, Added Complexity

In the grand story of human origins, the invention of agriculture is one of the most pivotal chapters.  It is generally agreed that farming first arose in the Fertile Crescent about 12,000 years ago.  But did it arise in at one end of the Crescent and spread to the other?  Or did it arise independently in various locations across the entire region, from modern Israel to modern Iran? 

Photo caption: Hordeum spontaneum, wild barley from Chogha Golan, Iran. [Image courtesy of TISARP]

New research suggests that agriculture arose independently at various locations. While the newly developed agricultural techniques and selected grains probably spread quickly, newly published evidence suggests that the inventive process itself was widespread.  The research, conducted by Simone Riehl from the University of Tübingen in Germany along with colleagues from the Tübingen Senckenberg Center for Human Evolution and Paleoecology, is published in the July 5, 2013 issue of the journal Science.

A key debate in human evolution is whether momentous changes such as agriculture occur in big, rapid, and isolated bursts, or whether such grand changes are the cumulative result of smaller changes widely distributed over vast areas and long periods of time.  This new evidence seems to support the view that changes are distributed and cumulative rather than rapid.

Field work in Chogha Golan, Iran, led Riehl’s team to the discovery of wild, progenitor versions of barley, lentil, and wheat.  At the same site, early domesticated forms of these same plants are found, suggesting that the domestication occurred onsite.  Domesticated plants and animals form the core of agriculture and the economic basis for the rise of human cities and civilization.  

Tools and figurines were also found, dating from 12,000 to around 9,800 years before the present. The rise of agriculture in this region during this period set the stage for the growth of human population, the development of cities, and the rise of ever-more complex cultures.

The article is entitled "Emergence of Agriculture in the Foothills of the Zagros Mountains of Iran."  It appears in the 5 July 2013 issue of the journal Science.