Airway inflammation is associated with mucous cell metaplasia and increased intraepithelial stored mucosubstances in horses.

The research examines the relationship between airway inflammation and mucus production in horses, and suggests that a single lung biopsy may be useful for diagnosing diseases that affect the lungs generally.

Objective and Methodology

• The main aim of the research was to verify if a peripheral sample from the lung biopsy site adequately represents the whole lung. Additionally, it sought to gain insights into the connection between airway inflammation and mucus generation in the peripheral airways of horses.
• The study was conducted on lung tissue samples procured from five regions of the lung in two groups of horses – control and those affected by ‘heaves’. ‘Heaves’ is a chronic, non-infectious lung disease in horses, similar to human asthma, and is often triggered by the dust in stables. The categorization of horse groups was based on their clinical response to stabling.
• The research utilized tissue sections for semi-quantitative lesion scoring, quantifying the amount of stored mucosubstances (Vs) within the epithelium, counting the number of airways and the epithelial cells in the terminal airways.

Findings

• No noteworthy differences were discovered between lung regions or groups of horses which implied that the peripheral biopsy sample could be representative of the entire lung. This finding indicates that a peripheral sample can be used for diagnosis and study of diffusely affected lungs.
• A correlation was found between airway inflammation and mucous cell metaplasia (transformation of cells) and Vs (stored mucosubstances). The accumulation of these substances is related to an increase in the number of mucosal cells. This means that mucus buildup in horses is partly due to an increased number of mucus cells and is linked to airway inflammation.
• An important inference from this study is the potential therapeutic strategy for managing excessive mucus accumulation in horses. Given the correlation found between airway inflammation and mucus accumulation, therapies that aim to reduce airway inflammation could effectively minimize excessive mucus accumulation in horses.