Researchers have created a new tool that could accurately predict lifespan of organisms and assess their current health state.
They have also discovered the regulatory mechanism that extends "healthspan" - the time in which an organism is at its optimal health.
Researchers at South Korea's Institute for Basic Science Centre for Plant Ageing Research and Princeton University in US have created their own health assessment for Caenorhabditis elegans roundworms (C elegans), modelled after the Short Physical Performance Battery (SPPB), one of the most widely used tests of physical performance in elderly humans, which can accurately predict their future health.
Among other things, the SPPB measures walking speed which was the inspiration for the C elegans version of the test. The scientists recorded the maximum velocity (MV) of wild-type C elegans worms during timed 30 second sessions for a life time.
In the experiment, the worms all showed a decrease in MV from day 6 and onwards just as the movement ability of humans starts to decline at some point of our later life and onwards.
Additionally, they found that at day nine (midlife), the median lifespan of worms in the high MV group (23 days) was 35.3 per cent longer than that of the worms in the low MV group (17 days).
They concluded that MV of wild-type worms at day nine of adulthood is a reliable predictor of longevity. Another factor they observed was the state of C elegans mitochondria.
Elderly humans have weaker muscles and less strength resulted from mitochondrial defects which occur later in life.
C elegans with lower MV exhibit similar defects by midlife but there are far fewer defects in worms with higher MV at the same age.
These observations indicate that MV correlates with mitochondrial health expression, suggesting that MV can be a reliable indicator of the actual physical state.
The findings show that MV of C elegans is a reliable indicator of age-related physical decline, accurately reports movement ability and if measured in mid-adulthood, is predictive of future longevity.
The findings contradict the conclusions of a previous study that daf-2(e1370) insulin/IGF-1 signalling (IIS) mutants are less healthy than wild-type animals, disproportionately extending their "unhealthy" lifetime.
The daf-2 mutation affects the insulin/IGF-1 signalling (IIS) pathway which in turn has a direct effect on longevity through its control of the metabolism of nutrients and enhances many physiological functions with age.
Tests with daf-2 mutants showed that they had a higher MV than wild-type worms with age, especially at day 10 and after.
Even after all the wild-type worms had died at day 26 of adulthood, the daf-2 mutants still maintained on average 36 per cent of MV.
