What is asthma?

Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways, leading to difficulty breathing. It is a common condition that affects people of all ages, but it often begins during childhood. Asthma can vary in severity and can be triggered by various factors, including allergens, respiratory infections, exercise, cold air, and irritants such as smoke or pollution.


In individuals with asthma, the airways become inflamed and swollen, making them more sensitive to certain triggers. When exposed to these triggers, the muscles surrounding the airways can tighten (bronchoconstriction), and the airways may produce excess mucus, further narrowing the air passages. This results in symptoms such as:


  • Wheezing: A whistling or squeaky sound when breathing, particularly during exhalation.


  • Shortness of breath: Difficulty breathing, with a feeling of tightness in the chest.


  • Coughing: A persistent cough, which may worsen at night or with exposure to triggers.


  • Chest tightness: A sensation of pressure or constriction in the chest, often described as feeling like a heavy weight on the chest.


Asthma symptoms can range from mild to severe and may vary over time. Some individuals may have occasional symptoms, while others may experience frequent or persistent symptoms that interfere with daily activities and quality of life.


What is the relationship between asthma and oxidative stress?

Overall, oxidative stress plays a significant role in the pathogenesis and exacerbation of asthma. For example:

  • Inflammation and Oxidative Stress: Asthma is characterized by chronic inflammation of the airways, which involves the activation of immune cells and the release of inflammatory mediators. This inflammatory response can lead to increased production of reactive oxygen species (ROS) and oxidative stress within the airways. ROS can damage cells and tissues, exacerbating airway inflammation and contributing to asthma symptoms such as airway narrowing and mucus production.


  • Antioxidant Defenses: The body has natural antioxidant defenses to neutralize ROS and prevent oxidative damage. However, in individuals with asthma, there may be an imbalance between ROS production and antioxidant defenses, leading to increased oxidative stress. Studies have shown that levels of antioxidants, such as glutathione and vitamin C, may be reduced in the airways of individuals with asthma, further contributing to oxidative stress and airway inflammation.


  • Airway Remodeling: Chronic oxidative stress in the airways can also contribute to structural changes known as airway remodeling, which may include thickening of the airway walls, increased smooth muscle mass, and alterations in the extracellular matrix. Airway remodeling can lead to permanent changes in lung function and worsen asthma symptoms over time.


  • Triggering Asthma Symptoms: Oxidative stress can trigger asthma symptoms and exacerbations by promoting bronchoconstriction (narrowing of the airways), increasing mucus production, and enhancing airway inflammation. Environmental factors such as air pollution, allergens, respiratory infections, and cigarette smoke exposure can also contribute to oxidative stress and exacerbate asthma symptoms in susceptible individuals.