Assessment of serum and synovial fluid MMP-3 and MPO as biomarkers for psoriatic arthritis and their relation to disease activity indices.

Research on biomarkers for the diagnosis and monitoring of psoriatic arthritis (PsA) is ongoing. The purpose of this study was to assess the potential of serum and synovial fluid matrix metalloproteinase-3 (MMP-3) and myeloperoxidase (MPO) as biomarkers for PsA and their relation to disease activity indices. This case-control study involved 156 psoriatic arthritis patients, 50 gonarthrosis patients, and 30 healthy controls. The target parameters were measured with the enzyme-linked immunosorbent assay (ELISA) kits. Serum MMP-3 and MPO levels were elevated in the PsA patients in comparison to the two control groups (p < 0.001) and distinguished PsA from GoA patients and healthy controls with 100% accuracy. Synovial MMP-3 discriminated PsA from GoA patients irrespective of the presence of crystals (AUC = 1.00). PsA patients with crystals in the synovial fluid had elevated synovial MPO (p < 0.001) and were distinguished from PsA patients without crystals with accuracy of 88.50% and from GoA patients with accuracy of 88.30%. Synovial fluid MPO was positively associated with the following indicators of disease activity: VAS (rs = 0.396); DAPSA (rs = 0.365); mCPDAI (rs = 0.323). Synovial MMP-3 showed a weaker positive association with DAPSA (rs = 0.202) and mCPDAI (rs = 0.223). Our results suggest that serum MMP-3 and MPO could serve as biomarkers for PsA. Synovial fluid MMP-3 showed a potential as a biomarker for PsA versus GoA. Synovial MPO could be utilized as a marker for the presence of crystals in PsA patients.

An assessment of potential biomarkers of environment enteropathy and its association with age and microbial infections among children in Bangladesh.

Interventional studies targeting environment enteropathy (EE) are impeded by the lack of appropriate, validated, non-invasive biomarkers of EE. Thus, we aimed to validate the association of potential biomarkers for EE with enteric infections and nutritional status in a longitudinal birth cohort study. We measured endotoxin core antibody (EndoCab) and soluble CD14 (sCD14) in serum, and myeloperoxidase (MPO) in feces using commercially available enzyme-linked immunosorbent assay (ELISA) kits. We found that levels of serum EndoCab and sCD14 increase with the cumulative incidence of enteric infections. We observed a significant correlation between the fecal MPO level in the children at 24 months of age with the total number of bacterial and viral infections, the total number of parasitic infections, and the total number of diarrheal episodes and diarrheal duration. We observed that the levels of serum EndoCab, sCD14, and fecal MPO at 3 months of age were significantly associated with whether children were malnourished at 18 months of age or not. Biomarkers such as fecal MPO, serum EndoCab and sCD14 in children at an early age may be useful as a measure of cumulative burden of preceding enteric infections, which are predictive of subsequent malnutrition status and may be useful non-invasive biomarkers for EE.

Serum catalase, thiol and myeloperoxidase levels in children passively exposed to cigarette smoke.

BACKGROUND: Free radicals found in cigarette smoke can harm all tissues and cellular structures in the human body. Passive smoking increases free radical production, leads to the depletion of antioxidants and increases oxidative stress which causes lipid peroxidation. Many studies have been conducted to determine the effects of passive smoking on antioxidant enzymes and lipid levels in adults, but pediatric studies on this topic are few. In our study, we compared the levels of antioxidants, oxidants, total and LDL cholesterol in children exposed to passive cigarette smoking with a healthy control group that was not exposed to passive smoking. METHODS: A total of 41 children (4-17 years of age, 24 girls and 17 boys) exposed to passive smoking and 18 healthy girls and 12 healthy boys were included in this study. Secondhand smoking was confirmed via measurement of the cotinine/creatinine ratio. Various sociodemographic characteristics of patients were recorded. The levels of catalase, thiol, myeloperoxidase were measured to determine the antioxidant and oxidant levels in children, while the levels of total cholesterol and LDL cholesterol were measured to determine the alterations in lipid profile. RESULTS: The groups were similar in regard to demographic characteristics. Myeloperoxidase levels were significantly higher in the passive cigarette smoking group compared to the non-exposure group; however, catalase and thiol levels were similar. In regard to lipid profile, the levels of total cholesterol and LDL cholesterol were also similar in those with and without exposure to passive smoking. CONCLUSIONS: Our findings suggest that the effects of passive smoking initially influence oxidants (MPO), but not antioxidants (thiol and catalase). However, it is apparent that passive smoking adversely affects oxidative balance in children and this may lead to the development of various diseases which could cause significant morbidity and mortality.

Flow cytometric assessment of myeloperoxidase in bovine blood neutrophils and monocytes.

Myeloperoxidase (MPO) is a lysosomal peroxidase enzyme mainly stored in the azurophilic granules of neutrophils playing an important role in innate immunity for first-line protection against microorganisms in many species including cattle. As such, determination of MPO has become of great interest for the diagnosis of infectious and inflammatory diseases in multiple species such as humans. In cattle, MPO determination is rarely done because methods to assess MPO in this species are limited: functional assays have been described earlier, but so far, the quantification of MPO at the single cell level has not been done yet. In the present paper, an innovative flow cytometric method to assess MPO in blood leukocytes of dairy cattle is described. A commercial anti-bovine MPO was used following density gradient separation to isolate polymorphonuclear (PMN) and mononuclear (MN) leukocytes from blood. Identification of PMN and MN, subdivided in monocytes and lymphocytes, was based on the expression of the surface markers CH138A and CD172A. The optimized protocol was subsequently evaluated on blood samples of 17 Holstein Friesian heifers. Myeloperoxidase expression was measured flow cytometrically and visualized by fluorescence microscopic imaging of sorted PMN and MN populations. We suggest this innovative method to be useful in the field for early detection of cows at higher risk for inflammatory diseases such as mastitis and metritis during the transition period.

Assessment of systemic inflammation by time-trends of blood granulocyte count and plasma myeloperoxidase and elastase concentrations following colic surgery in horses.

OBJECTIVE: To determine changes in blood granulocyte counts and in plasma myeloperoxidase (MPO) and elastase (ELT) concentrations in surgical colic cases, and to determine the relationship between these changes and the surgical procedure performed, occurrence of postoperative ileus, and final outcome. DESIGN: Prospective clinical study conducted over a 12-month period. SETTING: University teaching hospital. ANIMALS: Fifty-three horses undergoing emergency laparotomy and surviving at least 12 hours postoperatively. INTERVENTIONS: Blood samples were taken before surgery, during surgery, at the recovery from anesthesia, and then serially until the 150th hour after the first blood sampling. Granulocyte counts were performed by an automated cell hematology analyzer. Specific ELISAs were performed for the MPO and ELT measurements. Mixed models were used to compare the time-trends of the 3 parameters. MEASUREMENTS AND MAIN RESULTS: Taking all horses together, the time-trends of MPO and ELT were not significantly different from each other, but they were significantly different from the granulocyte time-trend. The type of surgical procedure did not influence the time-trends of the 3 parameters. Significant changes in the granulocyte time-trends were associated with postoperative ileus and outcome. Significant changes in the MPO time-trends were associated with outcome. The ELT time-trends were not influenced by ileus or outcome. CONCLUSIONS: Granulocyte counts and MPO change over time and are related to the severity of the inflammatory reaction in surgical colic cases. These time-trends may allow evaluation of treatment efficacy in an effort to modulate excessive granulocyte activation and degranulation.

Assessment of oxidative stress and inflammation in prediabetes-A hospital based cross-sectional study.

BACKGROUND AND AIM: Prediabetes is associated with dysglycemia, obesity, inflammation and endothelial dysfunction, contributing towards the pathogenesis of cardiovascular diseases rendering them vulnerable for the same. The current study intended to explore the risk of cardiovascular disease (CVD) related with prediabetes by assessing oxidative stress and inflammation using serum interleukin-6 (IL-6), myeloperoxidase (MPO) and urine microalbumin (MA) and their correlation with fasting plasma glucose (FPG) and physical measurements. MATERIALS AND METHODS: Based on FPG values, 80 subjects were grouped into prediabetes and healthy controls. IL-6 and MPO were estimated in serum sample whereas MA was estimated in random urine sample. RESULTS: Prediabetes group had significantly increased (p<0.05) mean anthropometric measurements and IL-6, MPO and MA as compared to healthy controls. MPO had significant correlation with FPG (r-0.388) in the prediabetes group. IL-6 and MPO showed a positive correlation with body mass index (BMI (r-0.339, r-0.327)), waist circumference (WC (r-484, r-0.493)) and waist-to-hip ratio (WHR (r-0.430, r-0.493)) while MA did not correlate with FPG and anthropometric measurements. CONCLUSION: This study suggests that prediabetes is associated with central adiposity, inflammation and oxidative stress predisposing them to an increased risk for CVD.

Assessment of a multi-assay biological diagnostic test for mood disorders in a Japanese population.

The current diagnostic tests for mood disorders, including major depressive disorder (MDD) and bipolar disorder (BD), have limitations. Inflammatory markers, growth factors, and oxidative stress markers are involved in the pathophysiology of mood disorders. A multi-assay biological diagnostic test combining these biomarkers might improve diagnostic efficiency. The plasma levels of soluble tumor necrosis factor receptor 2 (sTNFR2), epidermal growth factor (EGF), and myeloperoxidase were measured in 40 MDD patients, 40 BD patients and 40 controls in a Japanese population. We also investigated the plasma levels of these markers in 40 patients with schizophrenia to determine the utility of these markers in differential diagnosis. The plasma levels of sTNFR2 were significantly higher in BD and schizophrenia patients than in controls. The plasma levels of EGF and myeloperoxidase were significantly higher in patients with BD than in controls. The correct classification rate obtained from discriminant analysis with sTNFR2 and EGF between controls and mood disorders was 69.2%, with a sensitivity and specificity of 62.5% and 82.5%, respectively. The correct classification rate obtained from discriminant analysis with sTNFR2 and EGF between controls and BD was 85.0%, with a sensitivity and specificity of 77.6% and 92.5%, respectively. Our results suggest that sTNFR2 and EGF could be biological markers of BD. Further studies are needed to determine the utility of these markers in diagnostic tests for mood disorders.

Dual chronoamperometric detection of enzymatic biomarkers using magnetic beads and a low-cost flow cell.

In this work we report on the production of a low cost microfluidic device for the multiplexed electrochemical detection of magneto bioassays. As a proof of concept, the device has been used to detect myeloperoxidase (MPO), a cardiovascular biomarker. With this purpose, two bioassays have been optimized in parallel onto magnetic beads (MBs) for the simultaneous detection of MPO endogenous peroxidase activity and quantification of total MPO. Since the two bioassays produced signals of different magnitude for each concentration of MPO tested, two detection strategies have been compared, which entailed registering steady state currents (Iss) under substrate flow, and measuring the peak currents (Ip) produced in a stopped flow approach. As it will be shown, appropriate tuning of the detection and flow conditions can provide extremely sensitive detection, but also allow simultaneous detection of assays or parameters that would produce signals of different orders of magnitude when measured by a single detection strategy. In order to demonstrate the feasibility of the detection strategy reported, a dual MPO mass and activity assay has been finally applied to the study of 10 real plasma samples, allowing patient classification according to the risk of suffering a cardiovascular event.

The economic impact of implementing a multiple inflammatory biomarker-based approach to identify, treat, and reduce cardiovascular risk.

OBJECTIVES: To develop an economic model to estimate the change in the number of events and costs of non-fatal myocardial infarction (MI) and non-fatal ischemic stroke (IS) as a result of implementing routine risk-stratification with a multiple inflammatory biomarker approach. METHODS: Reductions in the numbers of non-fatal MI and non-fatal IS events and in related per-member-per-month (PMPM) and 5-year costs (excluding test costs) due to biomarker testing were modeled for a US health plan with one million beneficiaries. Inputs for the model included literature-based MI and IS incidence rates, healthcare costs associated with MI and IS, laboratory results of biomarker testing, MI and IS hazard ratios related to biomarker levels, patient monitoring and intervention costs and use/costs of preventative pharmacotherapy. Preventative pharmacotherapy inputs were based on an analysis of pharmacy claims data. Costs savings (2013 USD) were assessed for patients undergoing biomarker testing compared to the standard of care. Data from MDVIP and Cleveland Heart Lab supported two critical inputs: (1) treatment success rates and (2) the population distribution of biomarker testing. Incidence rates, hazard ratios, and other healthcare costs were obtained from the literature. RESULTS: For a health plan with one million members, an estimated 21,104 MI and 22,589 IS events occurred in a 5-year period. Routine biomarker testing among a sub-group of beneficiaries ≥35 years old reduced non-fatal MI and IS events by 2039 and 1869, respectively, yielding cost savings of over $187 million over 5 years ($3.13 PMPM), excluding test costs. Results were sensitive to changes in treatment response rates. Nonetheless, cost savings were observed for all input values. CONCLUSIONS: This study suggests that health plans can realize substantial cost savings by preventing non-fatal MI and IS events after implementation of routine biomarker testing. Five-year cost savings before test costs could exceed $3.13 PMPM.

No-reflow reversibility: a study based on serial assessment of multiple biomarkers.

No-reflow after primary percutaneous coronary intervention (pPCI) may be reversible. 40 patients undergoing pPCI were evaluated by assessing either improvement or lack of changes regarding angiographic and electrocardiographic indexes of no-reflow between admission and pre-discharge. Myeloperoxidase (MPO; in nanograms per milliliter), C-reactive protein (CRP; in milligrams per liter), endothelin-1 (ET-1; in nanograms per milliliter), angiopoietin-2 (Ang-2, in picograms per milliliter), and their pre-discharge/basal values variations (Δ) were related to no-reflow evolution. ΔMPO and ΔCRP were greater in patients with sustained no-reflow or lack of ST-segment resolution (STR) as compared with those with reversible no-reflow or lack of STR (p = 0.033, p = 0.04, p < 0.001, and p = 0.001, respectively), whereas ΔET-1 was similar in the two groups. ΔAng-2 was greater in patients with sustained no-reflow or lack of STR as compared with those with reversible no-reflow or lack of STR (p = 0.01 and 0.044, respectively). Bigger ΔMPO, ΔCRP (increasing levels), and ΔAng-2 (decreasing levels) are associated with sustained no-reflow, thus they might have a role in no-reflow evolution.

Assessment of a multi-assay, serum-based biological diagnostic test for major depressive disorder: a pilot and replication study.

Despite decades of intensive research, the development of a diagnostic test for major depressive disorder (MDD) had proven to be a formidable and elusive task, with all individual marker-based approaches yielding insufficient sensitivity and specificity for clinical use. In the present work, we examined the diagnostic performance of a multi-assay, serum-based test in two independent samples of patients with MDD. Serum levels of nine biomarkers (alpha1 antitrypsin, apolipoprotein CIII, brain-derived neurotrophic factor, cortisol, epidermal growth factor, myeloperoxidase, prolactin, resistin and soluble tumor necrosis factor alpha receptor type II) in peripheral blood were measured in two samples of MDD patients, and one of the non-depressed control subjects. Biomarkers measured were agreed upon a priori, and were selected on the basis of previous exploratory analyses in separate patient/control samples. Individual assay values were combined mathematically to yield an MDDScore. A 'positive' test, (consistent with the presence of MDD) was defined as an MDDScore of 50 or greater. For the Pilot Study, 36 MDD patients were recruited along with 43 non-depressed subjects. In this sample, the test demonstrated a sensitivity and specificity of 91.7% and 81.3%, respectively, in differentiating between the two groups. The Replication Study involved 34 MDD subjects, and yielded nearly identical sensitivity and specificity (91.1% and 81%, respectively). The results of the present study suggest that this test can differentiate MDD subjects from non-depressed controls with adequate sensitivity and specificity. Further research is needed to confirm the performance of the test across various age and ethnic groups, and in different clinical settings.

Race-specific associations of myeloperoxidase with atherosclerosis in a population-based sample: the Dallas Heart Study.

OBJECTIVE: Myeloperoxidase (MPO) is a leukocyte-derived enzyme that appears to be directly involved in atherosclerosis development. We evaluated the association of circulating MPO with coronary and aortic atherosclerosis in a large, multiethnic population. METHODS AND RESULTS: Plasma levels of MPO were measured in 3294 subjects participating in the Dallas Heart Study, a probability-based population sample. Coronary artery calcification (CAC) was measured by EBCT, and abdominal aorta plaque prevalence (AP) and burden (APB), as well as abdominal aorta wall thickness (AWT) were determined by MRI. Associations between MPO and atherosclerosis phenotypes were assessed in multivariable analyses adjusting for traditional atherosclerosis risk factors. MPO levels in the 4th compared with 1st quartile independently associated with prevalent AP (OR 1.41, 95% CI 1.08-1.84), APB (beta coefficient 0.23, p = 0.02), and AWT (beta coefficient 0.04, p = 0.03), but not with prevalent CAC (OR 0.84, 95% CI 0.61-1.17). MPO remained associated with aortic atherosclerosis phenotypes but not coronary calcification after adjustment for other inflammatory biomarkers. A significant interaction was observed between race/ethnicity, MPO and AP (p(interaction) = 0.038), such that MPO levels in the 4th vs 1st quartile associated with prevalent AP in African Americans, (OR 1.81, 95% CI 1.23-2.65) but not in White or Hispanic participants (OR 0.99, 95% CI 0.68-1.44). CONCLUSION: Higher levels of MPO associated with aortic but not coronary atherosclerosis, with significant associations limited to African American participants. These findings suggest that MPO might be a novel risk factor contributing to racial disparities in peripheral vascular disease.

Myeloperoxidase is not useful for the early assessment of patients with chest pain.

BACKGROUND: Myeloperoxidase (MPO) has been listed as a potentially useful risk marker in acute coronary syndrome. However, its clinical utility in patients with acute chest pain is not yet defined. DESIGN AND METHODS: MPO (Architect, Abbott Diagnostics) was measured in 120 healthy controls and 303 chest pain patients who had been admitted to the coronary care units of three Swedish hospitals. RESULTS: Chest pain patents had significantly higher median MPO levels compared to healthy controls (120.6 vs. 78. 9 pmol/L; p<0.001). However, MPO was not useful for the diagnosis of myocardial infarction (c-statistics 0.61 [95% CI 0.54-0.67]), and Cox regression analysis revealed no independent association between MPO and mortality (adjusted hazard ratio 1.3 [95% CI 0.8-2.0]) or the composite endpoint (adjusted hazard ratio 1.1 [95% CI 0.8-1.5]) after a median follow-up of 4.9 years. CONCLUSIONS: MPO provided no clinically relevant information in the present population of chest pain patients.

Iridium oxide nanomonitors: clinical diagnostic devices for health monitoring systems.

The objective of this research is to demonstrate the potential of iridium oxide (IrOx) nanowires based device towards detection of proteins that are disease biomarkers. This device is based on electrical detection of protein biomarkers wherein an immunoassay is built onto the iridium oxide nanowires that in turn undergoes specific electrical parameter perturbations during each binding event associated with the immunoassay. Detection of two inflammatory proteins C-reactive protein (CRP) and Myeloperoxidase (MPO) that are biomarkers of cardiovascular diseases is demonstrated. The performance metrics of the device in response to the two biomarkers in pure form and in serum samples were evaluated and compared to standard ELISA assays. The methodology that has been adopted is based on measuring impedance and calibrating its change in magnitude with concentration of proteins. We demonstrate the following performance metrics: limits of detection up to 1 ng/ml for CRP and 500 pg/ml for MPO in pure and serum samples; linear dynamic range of detection from 10 ng/ml to 100 microg/ml for CRP and 1 ng/ml to 1 microg/ml for MPO and cross-reactivity contained at less than 10% of selective binding for both the inflammatory proteins. Iridium oxide has an ability to detect very small changes to the surface charge and this capability is utilized for achieving the performance metrics and forms the basis of the key innovations of this technology, which are, improving the selectivity and sensitivity of detection.

Investigation of a multimarker approach to the initial assessment of patients with acute chest pain.

Early identification of acute coronary syndrome (ACS) is important to guide therapy at a time when it is most likely to be of value. In addition, predicting future risk helps identify those most likely to benefit from ongoing therapy. Cardiac troponin T (cTnT) is useful for both purposes although cannot reliably rule out ACS until 12 hours after pain onset and does not fully define future risk. In this review article we summarize our previously published research, which assessed the value of myocyte injury, vascular inflammation, hemostatic, and neurohormonal markers in the early diagnosis of ACS and risk stratification of patients with ACS. In addition to cTnT, we measured heart fatty acid binding protein (H-FABP), glycogen phosphorylase-BB, high-sensitivity C-reactive protein, myeloperoxidase, matrix metalloproteinase 9, pregnancy-associated plasma protein-A, D-dimer, soluble CD40 ligand, and N-terminal pro-brain natriuretic peptide (NT-proBNP). Of the 664 patients enrolled, 415 met inclusion criteria for the early diagnosis of acute myocardial infarction (MI) analysis; 555 were included in the risk stratification analysis and were followed for 1 year from admission. In patients presenting <4 hours from pain onset, initial H-FABP had higher sensitivity for acute MI than cTnT (73% vs. 55%; P=0.043) but was of no benefit beyond 4 hours when compared to cTnT. On multivariate analysis, H-FABP, NT-proBNP, and peak cTnT were independent predictors of 1-year death/MI. Our research demonstrated that, in patients presenting within 4 hours from pain onset, H-FABP may improve detection of ACS. Measuring H-FABP and proBNP may help improve long-term risk stratification.

Assessment of myeloperoxidase and oxidative alpha1-antitrypsin in patients on hemodialysis.

BACKGROUND AND OBJECTIVES: The present study assesses the effects of the oxidative stress marker, myeloperoxidase (MPO), and the possible MPO-related oxidative stress marker, oxidative alpha(1)-antitrypsin (oxAT), on carotid intima-media thickness (CIMT) and protein-energy wasting (PEW) in patients on hemodialysis (HD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Blood samples were obtained from 383 patients before HD to measure WBC count, serum albumin, lipids, high-sensitivity C-reactive protein (CRP), alpha(1)-antitrypsin (AT), interleukin-6, oxidative LDL-C, MPO, and oxAT. We assessed both CIMT and the geriatric nutritional risk index (GNRI) in this cross-sectional competitive study. RESULTS: Levels of MPO and oxAT correlated. Myeloperoxidase was associated with max-CIMT, and oxAT correlated with max-CIMT and GNRI. Multivariate linear regression models showed that MPO and oxAT were independent predictors of increasing max-CIMT, whereas oxAT, but not MPO, independently correlated with GNRI. In four combined MPO and oxAT groups classified according to median values, a multinomial logistic regression model showed that high MPO together with high oxAT was independently associated with increased max-CIMT. Moreover, the OR for max-CIMT with positive PEW and high MPO was significantly increased in the four groups with combined MPO and PEW. CONCLUSIONS: High MPO with high oxAT and high MPO with PEW seem to contribute to plaque formation in patients on HD, whereas elevated MPO or oxAT alone might not predict increasing CIMT. In contrast, a high oxAT value seems to be an independent predictor of PEW in patients on HD.

Assessment of the multiple-biomarker approach for diagnosis of myocardial infarction in patients presenting with symptoms suggestive of acute coronary syndrome.

BACKGROUND: Cardiac troponin is the preferred biomarker for detecting acute myocardial injury and infarction (MI). We studied whether multiple biomarkers of numerous pathophysiological pathways would increase the diagnostic accuracy for detecting MI. METHODS: Seven biomarkers [myeloperoxidase, soluble CD40 ligand, placental growth factor, matrix metalloproteinase 9 (MMP-9), high-sensitivity C-reactive protein (hsCRP), cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic peptide] and estimated glomerular filtration rate were measured in 457 patients presenting on admission with symptoms suggestive of acute coronary syndrome. Twenty-five patients (5.4%) received MI diagnoses. Clinical sensitivities and specificities were evaluated from 99th-percentile reference values. Forward and backward stepwise logistic regression modeling techniques were used to identify biomarkers that were independently predictive of MI. RESULTS: Biomarker sensitivities ranged from 20% to 96%, and specificities ranged from 19% to 89%. MMP-9 had the highest sensitivity, but its specificity was 19%. cTnI demonstrated a sensitivity of 72% (95% CI, 51%-88%) and a specificity of 89% (95% CI, 85%-92%). In multivariate models, cTnI (P < 0.001) and either hsCRP (P = 0.009) or MMP-9 (P = 0.03) were independently predictive of MI. Addition of hsCRP or MMP-9 increased the specificity to 95% (95% CI, 92%-97%) or 91% (95% CI, 88%-94%), respectively, but reduced the sensitivity to 56% (95% CI, 35%-76%) and 68% (95% CI, 47%-85%) relative to cTnI alone. CONCLUSIONS: Our findings indicate that the most clinically accurate biomarker for the early diagnosis of MI is the use of cTnI alone, rather than a multiple-biomarker approach, when an analytically robust cardiac troponin assay based on the 99th percentile is used.

Assessment of serum myeloperoxidase in children with bronchial asthma.

BACKGROUND: The role of neutrophils and myeloperoxidase (MPO) - assumed to be a marker of neutrophil activation - in bronchial asthma is still unclear, and the literature is controversial. METHODS: To investigate the participation of neutrophils and their products in childhood asthma, we assessed neutrophil counts and serum MPO in 175 children with bronchial asthma. Ninety of them were asymptomatic, and 85 of them were symptomatic within the last 2 weeks before examination. Bacterial infection of the lower respiratory tract (LRTI) was present in 34 and viral infection in 49 patients. As controls, 45 patients with cystic fibrosis, 23 patients with bacterial LRTI, and 87 healthy children were recruited. RESULTS: Median neutrophil counts (3135 cells/microl) and serum MPO levels (352 microg/l) were not different in children with bronchial asthma from healthy controls (2220 cells/microl and 401 microg/l, respectively), whereas in patients with cystic fibrosis and bacterial LRTI, neutrophil counts and MPO levels were increased. Asthmatic children with bacterial infection had significantly higher serum MPO and neutrophil counts then asthmatic children with viral infection or without infection. In addition, a significant correlation was found between serum MPO and neutrophil counts and C-reactive protein (CRP), and between neutrophil counts and CRP, but no relationship was detected for serum MPO and disease activity or lung function. CONCLUSIONS: Our data indicate that serum MPO - a marker of neutrophil activation - does not contribute to the assessment of the inflammatory process in childhood asthma. In addition, measurement of serum MPO appears not to be useful in assessing the participation of the neutrophil in asthmatic children. However, assessment of MPO may be useful to distinguish between bacterial and viral infection.

Assessment of myeloperoxidase activity in renal tissue after ischemia/reperfusion.

We have shown that a photometric assay of myeloperoxidase derived from rat blood polymorphonucleocytes employing 3,3',5,5'-tetramethylbenzidine as substrate is more sensitive than an established assay employing o-dianisidine. We went on to demonstrate that rat renal tissue is capable of inhibiting peroxidase activity. This activity approached 100% when the rat renal supernate was incubated at 60 degree C for 2 h and the assay was conducted in the presence of a 10-fold higher concentration of hydrogen peroxide (H2O2). Rat kidneys undergoing 45 min ischaemia and 1,3 and 6 h reperfusion in vivo, exhibited significant increases in myeloperoxidase activity, indicating tissue polymorphonucleocyte accumulation. Monoclonal antibodies against rat intercellular adhesion molecule 1 (ICAM-1) and CD18 of beta 2-integrins administered both 5 min before a period of 45 min renal ischaemia (20 micrograms/kg i.v.) and at the commencement of 1 h reperfusion (20 micrograms/kg i.v.) reduced renal tissue polymorphonucleocyte accumulation. However, similar treatment with the parent murine antibody immunoglobulin G1 (IgG1) and an unrelated murine antibody, IgG2a, also significantly reduced renal tissue polymorphonucleocyte accumulation. In conclusion, we demonstrate that the rat renal suppression of peroxidase activity can be overcome by a combination of heat inactivation and the provision of excess assay H2O2. In addition, the available evidence suggests that murine monoclonal antibodies against rat adhesion molecules may exert non-specific actions in our model of renal ischaemia/reperfusion in vivo.

Blood levels of reduced/oxidized glutathione and plasma concentration of ascorbic acid during eccentric and concentric exercises of similar energy cost.

In an attempt to assess the possible oxidative stress associated with the transient exercise-induced activation of polymorphonuclear neutrophils (PMN), we compared the effects of eccentric and concentric exercises (downhill run: DR and uphill walk: UW, respectively) of equal duration (35 min) and similar energy cost (60% VO2max) on plasma levels of ascorbic acid ([AA]) and blood concentration of reduced ([GSH]) and oxidized ([GSSG]) glutathione. Eight healthy male subjects took part in this study. Plasma concentration of myeloperoxidase ([MPO]) was used as a specific marker of PMN activation. While there were no significant changes in [MPO] and [AA] in UW experiments, [MPO] increased (+80%) and [AA] decreased significantly during DR tests (P < 0.01 and P < 0.05, respectively). A significant negative relationship was observed between [AA] and [MPO] in DR experiments only (r = -0.49; P < 0.01). Mean (+/- SEM) basal GSH and GSSG concentrations, calculated by pooling the values measured before both tests, were 0.54 +/- 0.02 and 0.12 +/- 0.007 mM, respectively. The blood concentration of these compounds remained practically unchanged in both exercise tests. These results confirm the role played by the eccentric component of muscle contraction in transient exercise-induced PMN activation and suggest that this activation was partly involved in the decrease in [AA] observed in DR experiments. The oxidant stress associated with the exercise protocol used in this study was insufficient to alter blood levels of reduced and oxidized glutathione.