Myeloperoxidase as an Active Disease Biomarker: Recent Biochemical and Pathological Perspectives

Abstract

Myeloperoxidase (MPO) belongs to the family of heme-containing peroxidases, produced mostly from polymorphonuclear neutrophils. The active enzyme (150 kDa) is the product of the MPO gene located on long arm of chromosome 17. The primary gene product undergoes several modifications, such as the removal of introns and signal peptides, and leads to the formation of enzymatically inactive glycosylated apoproMPO which complexes with chaperons, producing inactive proMPO by the insertion of a heme moiety. The active enzyme is a homodimer of heavy and light chain protomers. This enzyme is released into the extracellular fluid after oxidative stress and different inflammatory responses. Myeloperoxidase is the only type of peroxidase that uses H2O2 to oxidize several halides and pseudohalides to form different hypohalous acids. So, the antibacterial activities of MPO involve the production of reactive oxygen and reactive nitrogen species. Controlled MPO release at the site of infection is of prime importance for its efficient activities. Any uncontrolled degranulation exaggerates the inflammation and can also lead to tissue damage even in absence of inflammation. Several types of tissue injuries and the pathogenesis of several other major chronic diseases such as rheumatoid arthritis, cardiovascular diseases, liver diseases, diabetes, and cancer have been reported to be linked with MPO-derived oxidants. Thus, the enhanced level of MPO activity is one of the best diagnostic tools of inflammatory and oxidative stress biomarkers among these commonly-occurring diseases.

Anti–Inflammatory and Antioxidant Properties of the Ethanol Extract of Clerodendrum Cyrtophyllum Turcz in Copper Sulfate-Induced Inflammation in Zebrafish

“…Activated neutrophils, monocytes, and some tissue macrophages release MPO at the site of inflammation. MPO catalyzes the reaction between hydrogen peroxide (H 2 O 2 ) and physiological halides (such as Cl − ) to form reactive oxidants such as hypochlorous acid (HOCl) [31]. In this study, EE effectively inhibited the expression of mpo at 20 and 40 µg/mL at 24 h. This suggests that EE has an anti-inflammatory role through the inhibition of leukocyte infiltration.…”

The prospective curative role of lipoxin A4 in induced gastric ulcer in rats: Possible involvement of mitochondrial dynamics signaling pathway

“…MPO is an indicator for neutrophil infiltration . The activation of the neutrophils causes increment of ROS production with subsequent gastric damage .…”

Exercise Training Enhances Platelet Mitochondrial Bioenergetics in Stroke Patients: A Randomized Controlled Trial

“…Prominent increases of TNF α and IL-1 occur within few hours in the inflammatory cascade and may be inadequate for the study for chronic stroke patients [29]. Therefore, IL-6 and MPO were reviewed in the study because they have been reported to be associated with chronic low-grade inflammation and good responses to exercise related anti-inflammatory effects [29,30].…”