Dr. Yoichiro Sugiyama

Abstract:

Airway reflexes are essential physiological responses that involve the coordinated activities of respiratory-related muscles in both the upper airway and the alimentary tract. Dysphagia is critical not only for ensuring adequate nutrition but also for managing respiratory conditions, thereby supporting overall homeostasis. Additionally, airway protective reflexes, such as coughing, are necessary for clearing the airways, which is vital for effective breathing and maintaining the swallowing reflex.

Oxidative stress can lead to DNA damage and changes in other biomolecules within peripheral tissues and the central nervous system. This stress may be linked to the pathological conditions of dysphagia, particularly in chronic respiratory diseases and cerebrovascular and neurodegenerative disorders. Aging also affects swallowing function due to the diminished activity of swallowing-related muscles and reduced sensitivity of the larynx in inducing the swallowing reflex, which is likely related to decreased antioxidant levels.

The central nervous system, particularly the brainstem, plays a critical role in regulating the mechanisms of swallowing and coughing to ensure the effective transfer of food to the stomach and to protect the airway. Therefore, understanding the neuronal mechanisms involved in these functions is essential for assessing swallowing functions and managing effective treatment strategies for patients with dysphagia.

Moreover, exploring the relationship between the pathophysiology of dysphagia and oxidative stress could provide significant insights into improving swallowing function after cerebrovascular events, neurodegenerative diseases, and damage to peripheral tissues in the alimentary tract. This review aims to highlight the fundamental mechanisms of airway protective reflexes and their relations to oxidative stress while also addressing the clinical management of dysphagia. Additionally, we will examine the potential therapeutic effects of antioxidants, such as Twendee X®, on dysphagia and the deterioration of other airway protective reflexes.