Sensory decline in aging and neurodegeneration: A mitochondrial perspective

Sensory organs (touch, sight, hearing, smell, and taste) are the primary way humans perceive the environment. Accordingly, sensory decline deleteriously affects patients' quality of life, and it is often associated with a worse prognosis of related pathologies. This decline has been broadly described in aging and in the main aging-related neurodegenerative disorders, even though it is often understudied and considered a minor symptom. The molecular pathways that drive aging-associated sensory decline are broad and diverse; however, mitochondrial dysfunction has been described at the intersection of many of these mechanisms. Mitochondria have robust mechanisms to maintain their homeostasis. These mechanisms include, for example, the unfolded protein response, the antioxidant systems, and mitophagy. During aging, these mechanisms are dysregulated, which contributes to the dysfunction of the organelle. For example, increased reactive oxygen species generation and mitochondrial DNA mutations are present in cells and tissues, the dysregulation of which is crucial for the onset of sensory decline. In this bibliographical review, we systematically and comprehensively discuss the most significant and recent findings in the field. The studies we describe here suggest that targeting mitochondrial dysfunction could be a valid, innovative, and promising pharmacological target against sensory decline in aging and aging-related neurodegenerative disorders. Moreover, targeting mitochondrial dysfunction might have positive effects on other symptoms of aging and associated pathologies, including Parkinson's and Alzheimer's Diseases. Further research in the field could significantly contribute to decreasing sensory decline, which could positively impact both lifespan and healthspan.