Myeloperoxidase
Myeloperoxidase (MPO) is a peroxidase enzyme. MPO is most abundantly expressed in neutrophil granulocytes (a subtype of white blood cells). It is a lysosomal protein stored in the neutrophil. MPO has a heme (blood like) pigment, which causes its green color in secretions rich in neutrophils (immune cells that can destroy pathogens), such as pus and some forms of mucus.
Recent studies have reported an association between myeloperoxidase levels and the severity of coronary artery disease. It has been suggested that myeloperoxidase plays a significant role in the development of the atherosclerotic lesion and rendering plaques unstable. Again, inflammation is implicated in atherosclerosis and plaque buildup, thus a connection between inflammation and myeloperoxidase clearly exists.
A Cleveland Clinic Foundation 2003 study suggested that MPO could serve as a sensitive predictor for myocardial infarction (heart attack) in patients having chest pain [35]. Since then, there have been over 100 published studies documenting the utility of MPO testing. Most recently, a Canadian group reported that elevated MPO levels more than doubled the risk for cardiovascular mortality over a 13-year period, and measuring both MPO and CRP provided added benefit for risk prediction than just measuring CRP alone [36].
Alzheimer’s, Parkinson’s, and MS all have a MPO connection. In an article by Texas scientists titled, Microglia and myeloperoxidase: A deadly partnership in neurodegenerative disease, the authors reiterate the connection between these diseases and inflammation [37]. “The presence of [MPO] in these diseased brains has been reported by a number of investigators,” they stated. They also believe that MPO is involved in the perpetuation of inflammation and is a likely target for treatment. This has yet to be proven, and MPO should be viewed as a marker for inflammation, rather than a target, pending more definitive research. However, with an association between MPO, cardiovascular disease and Alzheimer’s illuminated, it makes sense to perform both the MPO and CRP tests together, to get a better picture of current or future disease risk. If an MPO and CRP combination test is more instructive compared to a single test, imagine the diagnostic power of combining more of these tests into your health portfolio.