Association between Plasma Myeloperoxidase and Free 3-Nitrotyrosine Levels in Patients with Coronary Artery Disease

Abstract

<span style="font-size:10.0pt;font-family:;" "=""><strong>Objective</strong></span><span style="font-size:10.0pt;font-family:;" "=""><strong>:</strong></span><span style="font-size:10.0pt;font-family:;" "=""> Myeloperoxidase (MPO) is an inflammatory enzyme that is mainly released by activated neutrophils and monocytes. 3-nitrotyrosine (NT) is a stable inflammatory end product of MPO that </span><span style="font-size:10.0pt;font-family:;" "="">is</span><span style="font-size:10.0pt;font-family:;" "=""> produced through nitrosylation of free and protein-bound tyrosines. Determination of the exact levels of free NT is technically a challenging matter. Also, there is limited information about the relationship between MPO and free NT levels and elevation of them in the plasma of patients with coronary artery disease (CAD). Therefore, we sought to determine the exact level of plasma free NT with a simple and exquisite technique in CAD patients. <strong>Methods:</strong><span></span><span></span> This study included 50 stable angina, 50 unstable angina patien</span><span style="font-size:10.0pt;font-family:;" "="">t</span><span style="font-size:10.0pt;font-family:;" "="">s, and 50 control subjects. Plasma MPO concentration was measured with an immunoassay method. Plasma free NT level was determined by a modified HPLC-fluorescence method. Lipid profile, high sensitivity C-re</span><span style="font-size:10.0pt;font-family:;" "="">active protein (hsCRP) and other clinical risk factors of patients were also assigned. <strong>Results:</strong> Plasma level of free NT was</span><span style="font-size:10.0pt;font-family:;" "=""> efficiently measured by the HPLC-fluorescence method. Plasma levels of MPO and NT were significantly higher in patients with stable and unstable CAD than in control subjects (P < 0.001). There was a significant correlation between the two substances in CAD patients (P < 0.001). <strong>Conclusions:</strong> We determined plasma free NT levels with a sensitive HPLC-fluorescence method with some modifications in a clinical scale. Plasma levels of MPO and NT </span><span style="font-size:10.0pt;font-family:;" "="">we</span><span style="font-size:10.0pt;font-family:;" "="">re profoundly elevated in CAD patients. The significant relationships of the two substances and elevation of them may have useful clinical implication in patients with stable and unstable CAD</span><span style="font-size:10.0pt;font-family:;" "="">.</span

3-Nitrotyrosine quantification methods: Current concepts and future challenges

“…Since 3-NT is not a fluorescent compound, it can only be detected using a fluorescence detector after structural modifications, such as the reaction of the amino group of 3-NT with a suitable derivatizing reagent [80]. For instance, Pourfarzam et al [32] used 4-fluoro-7-nitrobenzo-2-oxal,3-diazole (NBD-F) as derivatization reagent. This reagent has been reported in several studies and the results obtained were comparable among them [32].…”

“…For instance, Pourfarzam et al [32] used 4-fluoro-7-nitrobenzo-2-oxal,3-diazole (NBD-F) as derivatization reagent. This reagent has been reported in several studies and the results obtained were comparable among them [32]. The fluorescent dyes used in the derivatization step of amino acids significantly improve the sensitivity and specificity of detection.…”

“…Among the pathological conditions, there is a wide range of cardiovascular diseases, such as myocardial inflammation, heart failure and arteriosclerosis [5,27e30]. For instance, Shishehbor et al [31] and Poufarzam et al [32] demonstrated that 3-NT plasma levels are elevated in coronary artery disease (CAD) patients. Regarding atherosclerosis, it was found that atherosclerotic arteries have higher 3-NT levels than non-atherosclerotic blood vessels [33].…”

Protein Tyrosine Nitration in Plant Nitric Oxide Signaling

“…Besides MS-based methods, a wide array of chromatographic, immunochemical, and bio-sensing techniques has been reported to be useful for the identification and quantification of protein Tyr-nitration (recently reviewed in Bandookwala et al, 2020 ). After HPLC, nitrated proteins have been quantified also by UV detection ( Yang et al, 2010 ); by electrochemical detection with sensitivity and selectivity compared to immunodetection methods ( Vujacic-Mirski et al, 2020 ); by fluorescence detection after derivatization ( Pourfarzam et al, 2013 ); and also by photodiode array detection ( Teixeira et al, 2017 ). Size exclusion chromatography coupled to reverse phase-HPLC with diode array detection has been also developed to evaluate protein nitration ( Liu et al, 2017 ).…”

A highly selective and sensitive spectrofluorimetric method for the assessment of 3-nitrotyrosine in serum using (Eu(TTA)3Phen) photo probe

“…The results obtained by the proposed method are agreed with the results of the reference method. The comparison of the proposed photo probe for the determination of 3-nitrotyrosine with other published methods 43–49 is summarized in Table 3. It was revealed that the developed method exhibited good stability, lower limit of detection (8.6 × 10 −10 mol L −1 ) and wide linear range (2.3 × 10 −4 to 1.0 × 10 −9 mol L −1 ).…”