What is Kawasaki Disease (KD)?
Kawasaki disease (KD), also known as Kawasaki syndrome, is a rare but serious illness that primarily affects children, typically those under the age of 5. It is characterized by inflammation of the blood vessels (vasculitis) throughout the body, leading to a range of symptoms, including fever, rash, swelling of the hands and feet, and irritation and redness of the eyes.
The exact cause of Kawasaki disease is unknown, but it is believed to involve a combination of genetic predisposition and environmental triggers. It is thought to be an autoimmune disorder, where the body’s immune system mistakenly attacks its own tissues, particularly the blood vessels. However, no specific genetic or environmental factors have been definitively identified as the cause.
What is the relationship between KD and oxidative stress?
The relationship between Kawasaki disease (KD) and oxidative stress is an area of ongoing research, and while the exact mechanisms are not fully understood, there is evidence to suggest that oxidative stress may play a role in the pathophysiology of the disease. Here are some potential connections:
- Endothelial Dysfunction: KD is characterized by inflammation of the blood vessels (vasculitis), particularly affecting medium-sized arteries. Endothelial dysfunction, which involves impairment of the endothelial cells lining the blood vessels, is a key feature of vasculitis. Oxidative stress can contribute to endothelial dysfunction by promoting the production of reactive oxygen species (ROS) and impairing nitric oxide (NO) bioavailability, a molecule involved in regulating vascular tone and function.
- Inflammatory Response: Oxidative stress is closely linked to inflammation, and KD is considered to be an inflammatory disorder. During the acute phase of KD, there is an excessive activation of the immune system, leading to the release of pro-inflammatory cytokines and recruitment of inflammatory cells to the affected blood vessels. Inflammatory cells, such as neutrophils and macrophages, produce ROS as part of their antimicrobial defense mechanisms. Excessive ROS production during inflammation can contribute to tissue damage and exacerbate the inflammatory response.
- Antioxidant Defenses: Antioxidant defenses, including enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase, play a crucial role in protecting cells from oxidative damage. Studies have shown alterations in antioxidant enzyme activity and antioxidant capacity in children with KD, suggesting an imbalance between ROS production and antioxidant defenses. This imbalance may contribute to oxidative stress and tissue injury in KD.
- Coronary Artery Involvement: One of the most serious complications of KD is the development of coronary artery abnormalities, including dilation, aneurysm formation, and coronary artery inflammation (vasculitis). Oxidative stress has been implicated in the pathogenesis of coronary artery disease, and there is evidence to suggest that oxidative damage to the endothelium and vascular smooth muscle cells may contribute to the development of coronary artery abnormalities in KD.
In summary, while the precise role of oxidative stress in the pathogenesis of Kawasaki disease is still being elucidated, there is growing evidence to suggest that oxidative stress may contribute to endothelial dysfunction, inflammation, and coronary artery involvement in KD.