Cooler conditions can extend the lives of some animals, but the reason may involve more than a slower metabolism. A study published in Nature by researchers at the University of Cologne identifies a chemical signal that helps explain the effect in roundworms.
A signal from muscle to other tissues
The team studied Caenorhabditis elegans, a microscopic worm commonly used in aging research. Worms shifted from 20°C to 15°C during adulthood lived longer. Researchers traced part of this response to dihydrobiopterin, or BH2, a molecule produced in greater amounts by muscle tissue in cooler conditions.
BH2 can travel to tissues including the intestine and nervous system, where it is converted into BH4. This pathway supports the production of tyrosine, an amino acid involved in a range of biological processes.
Benefits observed without cooling
When researchers increased BH2 production in the worms, their lifespans increased at cooler, standard and warmer laboratory temperatures. Providing tyrosine also extended lifespan in some experiments. Activating the pathway was linked to less age-related protein damage, including fewer harmful protein clumps.
The researchers also observed related effects in human cells carrying proteins associated with Huntington's disease and ALS. These laboratory findings do not show that the approach can extend human lifespan or treat disease. People regulate their body temperature differently from worms, and the results do not support using tyrosine supplements as an anti-aging treatment.
By identifying a chemical pathway behind cold-related longevity in worms, the study offers researchers a new way to investigate how tissues communicate during aging. Further work will be needed to determine whether any part of this mechanism is relevant to human health.
