Hepatic ammonia metabolism declines with age through mitochondrial dysfunction and disrupted metabolic regulation, compromising the liver's capacity to maintain nitrogen homeostasis and triggering inflammatory and fibrogenic remodeling. This pathway represents a mechanistic link between liver aging and systemic dysfunction across multiple organ systems.
Key Points
- Mitochondrial dysfunction impairs ureagenesis and ammonia detoxification during aging
- Ammonia functions as a bioactive stress signal triggering senescence and inflammation
- Dysregulation affects liver-brain, liver-muscle, and liver-gut communication pathways
Longevity Analysis
Ammonia metabolism sits at the intersection of energy production and detoxification—two systems that deteriorate together during aging. When mitochondria lose efficiency, they cannot process nitrogen waste effectively, causing ammonia to accumulate systemically. This isn't merely a metabolic inconvenience; elevated ammonia acts as a stress signal that accelerates cellular senescence, disrupts protein quality control, and amplifies inflammation. The liver's declining ability to handle ammonia also compromises its communication with the brain, skeletal muscle, and gut microbiota, cascading effects that accelerate multiple aspects of aging. Therapeutic strategies targeting ammonia metabolism—whether through metabolic optimization, senescence intervention, or microbiota modulation—address a root mechanism rather than a symptom, offering a leverage point for extending both healthspan and lifespan.
Original published by Wiley Aging Cell, by Heng Zhang, Guangyu Liang, Anding Liu .