Concepts of oxidative stress and antioxidant defense in Crohn’s disease

Abstract

Oxygen free radical and lipid peroxides (oxidative stress) are highly reactive and represent very damaging compounds. Oxidative stress could be a major contributing factor to the tissue injury and fibrosis that characterize Crohn's disease. An imbalance between increased reactive oxygen species levels and decreased antioxidant defenses occurs in Crohn's patients. Decreased blood levels of vitamins C and E and decreased intestinal mucosal levels of CuZn superoxide dismutase, glutathione, vitamin A, C, E, and β-carotene have been reported for Crohn's patients. Increased levels of proinflammatory cytokines, such as interleukin-1 and -8 and tumor necrosis factor, have been detected in inflammatory bowel disease. Oxidative stress significantly increased the production of neutrophils, chemokines, and interleukin-8. These effects were inhibited by antioxidant vitamins and arachidonic acid metabolite inhibitors in human intestinal smooth muscle cells isolated from the bowels of Crohn's disease patients. The main pathological feature of Crohn's disease is an infiltration of polymorphonuclear neutrophils and mononuclear cells into the affected part of the intestine. Activated neutrophils produce noxious substances that cause inflammation and tissue injury. Due to the physiological and biochemical actions of reactive oxygen species and lipid peroxides, many of the clinical and pathophysiological features of Crohn's disease might be explained by an imbalance of increased reactive oxygen species and a net decrease of antioxidant molecules. This review describes the general concepts of free radical, lipid peroxide and antioxidant activities and eventually illustrates their interferences in the development of Crohn's strictures.

Comparative studies on extracts from Hericium erinaceus by different polarity reagents to gain higher antioxidant activities

“…Reactive oxygen species (ROS) and lipid peroxides are damaging compounds involved in the oxidative stress process. An imbalance between ROS levels and antioxidant defenses occurs in various different diseases, such as Crohn's disease (5). Intake of antioxidants is important to sustain an adequate level in order to balance the ROS in vivo.…”

Inflammatory Bowel Disease: Cytochemical Activity of Intracellular Enzymes of Peripheral Blood Neutrophils and Monocytes in Diagnosis

“…В патогенезе ВЗК получены неопровержимые доказательства роли митохондриальной дисфунк-ции. Обнаружение каких-либо признаков оксида-тивного стресса в клетках слизистой оболочки киш-ки, а также лейкоцитарных инфильтратах может указывать на нарушение адекватной работы мито-хондриального аппарата у пациентов с ВЗК [22,23].…”

Effect of tumor necrosis factor-α antagonists on oxidative stress in patients with Crohn’s disease

“…While the etiology is unknown, it is commonly thought that oxidative stress underlies the persistence of a chronic inflammatory process in the gut [1] . Oxidative stress is generally defined as an imbalance between pro-oxidant and anti-oxidant systems [2] .…”

“…The oxidative stress consists of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Excessive ROS attack target molecules such as lipids, proteins, and nucleic acids, and as a consequence can cause protein denaturation, inactivation of enzymes, and modifications to DNA [1,3,4] . Since CD is a disease characterized by neutrophil infiltration in the intestinal wall, there is a large degree of tissue damage because of the release of ROS [1,5] .…”

“…Excessive ROS attack target molecules such as lipids, proteins, and nucleic acids, and as a consequence can cause protein denaturation, inactivation of enzymes, and modifications to DNA [1,3,4] . Since CD is a disease characterized by neutrophil infiltration in the intestinal wall, there is a large degree of tissue damage because of the release of ROS [1,5] . To date, the influence of tumor necrosis factor (TNF)-α, which is the most effective treatment for CD, on oxidative stress, has not been much investigated [6] .…”