Tryptophan metabolism is differently regulated between large and small dogs

Area of Science:

• Gerontology and comparative physiology.
• Metabolomics and biomarker discovery.
• Animal models for human aging research.

Background:

• Companion dogs are increasingly used as aging models due to shared physiology and environment with humans.
• Dogs exhibit a size-longevity trade-off, with smaller breeds living longer than larger ones.
• Mechanisms behind this trade-off, like growth hormone/IGF-I pathways, are partially understood but require further investigation.

Purpose of the Study:

• To investigate the metabolomic differences across dog populations of varying sizes and ages.
• To identify potential physiological mechanisms underlying the size-longevity relationship in dogs.
• To explore the utility of companion dogs in understanding aging and metabolic processes.

Main Methods:

• Global metabolomic profiling was performed on a cohort of companion dogs from three US cities.
• Data analysis controlled for location, age, breed, and sex to identify significant metabolic signals.
• Statistical associations between specific metabolic pathways and dog weight were examined.

Main Results:

• Metabolomic profiles showed a strong geographical influence, surpassing signals from age, breed, or sex.
• After accounting for location, tryptophan metabolism was significantly associated with dog weight.
• Smaller dogs exhibited higher levels of metabolites within the tryptophan pathway compared to larger dogs.

Conclusions:

• Dog metabolomes are influenced by geographic location, highlighting environmental factors.
• Tryptophan metabolism is a key pathway linked to body size and potentially longevity in dogs.
• Companion dogs serve as a valuable model for exploring metabolic complexities, particularly the tryptophan network, in aging.