CRISPR + sickle cell disease
How gene editing is curing disease.
In human populations, women consistently outlive men, which suggests profound biological foundations for sex differences in survival. Quantifying whether such sex differences are also pervasive in wild mammals is a crucial challenge in both evolutionary biology and biogerontology.
Here, we compile demographic data from 134 mammal populations, encompassing 101 species, to show that the female’s median lifespan is on average 18.6% longer than that of conspecific males, whereas in humans the female advantage is on average 7.8%.
We do not find any consistent sex differences in aging rates. In addition, sex differences in median adult lifespan and aging rates are both highly variable across species. Our analyses suggest that the magnitude of sex differences in mammalian mortality patterns is likely shaped by local environmental conditions in interaction with the sex-specific costs of sexual selection.
FULL TEXT: PNAS
Nutrient and stress sensors mediate lifespan extensions that occur in response to many different environmental and physiological signals. The best known of these signals is dietary restriction, which extends lifespan in many species, from yeast to primates.
Dietary restriction was initially assumed to extend lifespan simply by reducing the rate at which cellular damage accumulates over time as a result of nutrient metabolism. Recently, however, an elegant experiment with Drosophila showed that dietary restriction produces a rapid decrease in the mortality rate (the daily chance of death), suggesting that dietary restriction counteracts the causes of ageing in an acute manner.
We now know that the longevity response to dietary restriction is actively regulated by nutrient-sensing pathways involving the kinase target of rapamycin (TOR), AMP kinase, sirtuins and insulin/insulin-like growth factor (IGF-1) signalling.
Unexpectedly, which nutrient sensor is most important in extending lifespan in response to dietary restriction depends on the way that dietary restriction is imposed. In C. elegans, for example, one nutrient sensor extends lifespan in response to life-long food limitation, another in response to every-other-day feeding and a third if dietary restriction begins in middle age.
SOURCE: Nature (2010)
Here we review two promising interventions, exercise and systemic exposure to young blood, that illustrate the validity of this holistic approach. Nonetheless, given the complexity of the aging process, ultimately we envision a multifaceted approach that targets pro-aging processes at the intracellular, intercellular, and systemic level to combat age-related functional decline.