"Long before it's in the papers"
October 14, 2015


Differences in longevity may show up at middle age

Oct. 14, 2015
Courtesy of the American Chemical Society
and World Science staff

Or­gan­isms with life­span-boosting genes may start to show that ad­van­tage most strongly af­ter hit­ting mid­dle age, if a new study with ti­ny worms is any in­dica­t­ion.

Why some peo­ple live much long­er than oth­ers is largely a mys­tery. The new study re­ports that in round­worms, char­act­er­istics of their met­a­bol­ism may ac­cu­rately pre­dict how long they live.

Worms with a longe­vity-conferring muta­t­ion, it ap­peared, are “are met­a­bol­ic­ally youth­ful com­pared to wild-type worms, but... this rel­a­tive youth only ap­pears in mid­dle age,” the re­search­ers wrote, re­port­ing their find­ings Sept. 18 in the Jour­nal of Pro­teome Re­search. The sci­en­tists say fur­ther work is needed to in­ves­t­i­gate how this hap­pens.

Oth­er than ad­dress­ing our cu­ri­os­ity and fears about grow­ing old, pre­dicting longe­vity has prac­ti­cal ap­plica­t­ions for re­tire­ment in­vesting and health care plan­ning, not to men­tion insur­ance com­pa­nies. 

Cur­rent tech­niques that es­ti­mate how long peo­ple will live weigh fac­tors in­clud­ing where they live, family med­i­cal his­to­ries and lifestyle choices. To im­prove these pre­dictions, re­search­ers have started draw­ing from ge­net­ics, but DNA only tells part of the sto­ry. 

The sci­en­tists, Ar­mand M. Leroi of Im­pe­ri­al Col­lege Lon­don and col­leagues, stud­ied the met­a­bol­ic pro­files of the ti­ny worm Caenorhab­di­tis el­e­gans to see if they could find pat­terns re­lat­ed to life ex­pect­an­cy.

The re­search­ers com­pared met­a­bol­ic changes in nor­mal worms with those of long-lived ones that had a ge­net­ic muta­t­ion known as daf-2(m41). By pro­fil­ing 26 metabo­lites, or break­down prod­ucts of me­tab­o­lism, the in­ves­ti­ga­tors said they could pre­dict the worms’ life­spans. 

The team al­so found that the two types of worms aged at dif­fer­ent rates. When the worms with a nor­mal life­span hit mid­dle age, their met­a­bol­ic pro­files in­dicated that they started get­ting old­er about 40 per­cent faster than when their long-lived coun­ter­parts hit mid­dle age.

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Organisms with lifespan-boosting genes may start to show that advantage most strongly after hitting middle age, if a new study with tiny worms is any indication. Why some people live much longer than others is a mystery. The new study reports that in the roundworms, metabolic profiles may accurately predict how long they live. Worms with a longevity-conferring mutation, it appeared, are “are metabolically youthful compared to wild-type worms, but that this relative youth only appears in middle age,” the researchers wrote, reporting their findings Sept. 18 in the Journal of Proteome Research. The scientists say further work is needed to investigate how this happens. Other than addressing our curiosity and fears about growing old, predicting longevity has practical applications for retirement investing and health care planning, not to mention insurance companies. Current techniques that estimate how long people will live weigh a number of factors, including location, family medical histories and lifestyle choices. To improve these predictions, researchers have started drawing from genetics, but DNA only tells part of the story. The scientists, Armand M. Leroi of Imperial College London and colleagues, studied the metabolic profiles of the tiny worm Caenorhabditis elegans to see if they could find patterns related to life expectancy. The researchers compared metabolic changes in normal worms with those of long-lived ones that had a genetic mutation, known as daf-2(m41). By profiling 26 metabolites, or breakdown products of metabolism, the investigators said they could predict the worms’ lifespans. The team also found that the two types of worms aged at different rates. When the worms with a normal lifespan hit middle age, their metabolic profiles indicated that they started getting older about 40 percent faster than when their long-lived counterparts hit middle age.