Free radicals, specifically reactive oxygen species (ROS) and reactive nitrogen species (RNS), are implicated in a wide range of disorders beyond the commonly discussed conditions affecting the cardiovascular system, brain, kidneys, and muscles.
Their dual role as both necessary signaling molecules and potentially damaging agents is a theme that extends into various other diseases and conditions.
Below, we explore some additional disorders where free radicals play a significant role.
Autoimmune Diseases
In autoimmune conditions such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), oxidative stress contributes to the pathogenesis and progression of disease.
In RA, for instance, ROS are involved in the inflammation of joints, leading to the destruction of cartilage and bone.
Antioxidant defense mechanisms are often compromised in autoimmune diseases, exacerbating tissue damage.
Respiratory Diseases
Chronic obstructive pulmonary disease (COPD) and asthma are characterized by chronic inflammation in the airways, where ROS play a key role.
In COPD, oxidative stress contributes to lung tissue damage, mucus production, and airway remodeling.
Similarly, in asthma, ROS are involved in airway inflammation, hyperresponsiveness, and remodeling, affecting breathing and lung function.
Skin Disorders
Skin is the largest organ of the body and is directly exposed to environmental sources of ROS, including UV radiation and pollution.
Conditions such as psoriasis, atopic dermatitis, and skin aging are associated with oxidative stress.
For example, ROS contribute to the inflammation and cell damage observed in psoriasis and can accelerate the aging process in the skin by degrading collagen and elastin fibers.
Gastrointestinal Disorders
Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is associated with increased oxidative stress.
ROS are involved in the inflammation of the gastrointestinal tract, leading to tissue damage and the typical symptoms of IBD.
Antioxidants have been explored as potential adjunct therapies to reduce oxidative damage in these conditions.
Eye Disorders
Oxidative stress is implicated in various eye diseases, including age-related macular degeneration (AMD), cataracts, and glaucoma.
In AMD, ROS damage the macula, leading to loss of central vision.
Oxidative stress contributes to the opacification of the lens observed in cataracts.
In glaucoma, increased oxidative damage is associated with the degeneration of retinal ganglion cells.
Metabolic Disorders
Obesity and metabolic syndrome are associated with increased oxidative stress, contributing to the development of insulin resistance and type 2 diabetes mellitus.
ROS are involved in the dysfunction of adipocytes and the development of fatty liver disease, exacerbating metabolic imbalances.
Neurodegenerative Diseases
Beyond Alzheimer's and Parkinson's disease, oxidative stress is implicated in other neurodegenerative conditions like Huntington's disease and amyotrophic lateral sclerosis (ALS).
In these diseases, ROS contribute to the degeneration of specific neuronal populations, leading to progressive loss of motor or cognitive functions.