Do Animals Age Like We Do?
Weighing more makes you live longer. At least this is true when we compare body mass and lifespans between species: the bowhead whale weighs more than 1,000 tons and lives more than 200 years whereas an Etruscan shrew weighs 1.8 grams and lives only 3.2 years. However, when comparing within species, this correlation holds true only for animals with short lifespans, not for species that live longer. This suggests that different mechanisms regulate lifespan for different animals. Because most pro-longevity interventions are based on studies of short-lived species such as mice and worms (e.g. c. Elegans), it is necessary to establish which are the shared and distinct mechanisms of lifespan modulation.
To do this, a group of researchers at Harvard University analyzed age-related changes in gene expression in 3 different tissues (brain, kidney and liver) across 41 species. The changes convey which molecular mechanisms are altered in cells and tissues due to aging. Across the analyzed tissues, they saw similar gene expression signatures with age, suggesting that different organs age in similar ways. However, when comparing across species they found both shared and divergent aging mechanisms. Processes involved in maintaining the cell’s genetic and structural integrity regulated longevity in short- and long-lived species. Conversely, inflammatory and metabolic processes regulated longevity in short-lived species only. Indeed, treatment with anti-inflammatory factors improved markers of cellular health in mice but not in human cells. By targeting a shared aging mechanism across species, the authors identified a secret compound, KU0063794, that promoted lifespan in mice as well as in primates.
Hence, these findings suggest the length of a species’ life dictates the mechanisms driving aging in their bodies. We might age more similarly to an elephant than a mouse. Hence, to develop successful pro-health and lifespan interventions, conserved molecular mechanisms across species must be targeted. However, the paper never addresses how healthspan is differently regulated across species. Looking at shared mechanisms that regulate health across animals should be a future goal of the group, as living longer is not always better if health is lacking.
This research was conducted at the Harvard Medical School in the Genetics Department by senior scientist Alexander Tyshkovskiy in the lab of Vadim Gladyshev, Professor of Medicine at Brigham and Women’s Hospital.
Corresponding Author: Allegra Carlotta Scarpa
Press Article: The evolution of aging and lifespan
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