Platelet Count and Platelet Indices in Patients with Stable and Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

Platelets play an important role in the pathophysiology of chronic obstructive pulmonary disease (COPD) by mediating thrombotic, inflammatory, and immune processes in the lung. We conducted a systematic review and meta-analysis of studies investigating the platelet count and three platelet indices, mean platelet volume (MPV), platelet distribution width (PDW), and platelet to lymphocyte ratio (PLR) in stable COPD vs. non-COPD patients and in stable COPD vs. acute exacerbation of COPD (AECOPD) patients (PROSPERO registration number: CRD42021228263). PubMed, Web of Science, Scopus and Google Scholar were searched from inception to December 2020. Twenty-seven studies were included in the meta-analysis, 26 comparing 4,455 stable COPD patients with 7,128 non-COPD controls and 14 comparing 1,251 stable COPD with 904 AECOPD patients. Stable COPD patients had significantly higher platelet counts (weighted mean difference, WMD = 13.39 x109/L, 95% CI 4.68 to 22.11 x109/L; p < 0.001) and PLR (WMD = 59.52, 95% CI 29.59 to 89.44; p < 0.001) than non-COPD subjects. AECOPD patients had significantly higher PLR values than stable COPD patients (WMD = 46.03, 95% CI 7.70 to 84.35; p = 0.02). No significant differences were observed in MPV and PDW. Between-study heterogeneity was extreme. In sensitivity analysis, the effect size was not modified when each study was sequentially removed. The was no evidence of publication bias. In our meta-analysis, specific platelet biomarkers were associated with stable COPD (platelet count and PLR) and AECOPD (PLR). However, the observed heterogeneity limits the generalizability of the findings. Further studies are required to determine their prognostic utility and the effects of targeted interventions in COPD.

Systemic transsulfuration pathway thiol concentrations in chronic obstructive pulmonary disease patients.

BACKGROUND: It is amply reported that patients with chronic obstructive pulmonary disease (COPD) have increased risk of cardiovascular disease (CVD). Recent evidence suggests that COPD patients have elevated concentrations of plasma homocysteine (Hcy), a transsulfuration pathway analyte that is commonly regarded as a CVD risk factor. DESIGN: We comprehensively investigated the plasma concentrations of transsulfuration pathway analytes, and their relationship with markers of oxidative stress and inflammation, to identify which low molecular thiols might play a pathophysiological role both in CVD and in COPD. Hcy, cysteine (Cys), glutathione (GSH), cysteinylglycine (CysGly), glutamylcysteine (GluCys), taurine (Tau), oxidative stress markers (TBARS and protein-SH, PSH) and the inflammation marker kynurenine/tryptophan (Kyn/Trp) ratio were measured in 54 COPD patients and 54 control subjects. RESULTS: We found increased concentrations of total Hcy (P < .01) and total CysGly (P < .05) in COPD patients when compared to controls. Total Hcy and CysGly were also significantly associated with abnormal lung function parameters and COPD severity. In COPD patients, total Hcy was significantly associated with the Kyn/Trp ratio (P = .0017) whereas total CysGly was significantly associated with both PSH (P = .0298) and the Kyn/Trp ratio (P = <.0001). CONCLUSION: Both total Hcy and CysGly concentrations were significantly associated with the presence and severity of COPD and with markers of oxidative stress (total CysGly) and inflammation (total Hcy and CysGly). This suggests that specific low molecular mass thiols might play a role in the inflammatory and oxidative stress pathways involved in both CVD and COPD.

Blood Cell Count Derived Inflammation Indexes in Patients with Idiopathic Pulmonary Fibrosis.

PURPOSE: Inflammation and immunity play a pivotal but yet unclear role in idiopathic pulmonary fibrosis (IPF), a chronic disorder characterized by progressive damage of lung parenchyma and severe loss of lung function despite optimal treatment. However, the pathophysiological and predictive role of combined blood cell count indexes of inflammation in IPF is uncertain. METHODS: Seventy-three patients with IPF and 62 healthy subjects matched for age, gender and smoking status were included in this cross-sectional study. RESULTS: We found significant differences in neutrophil to lymphocyte ratio (NLR), derived neutrophil to lymphocyte ratio (dNLR), monocyte to lymphocyte ratio (MLR), platelet to lymphocyte ratio (PLR), systemic inflammation response index (SIRI) and aggregate index of systemic inflammation (AISI) between IPF patients and healthy controls. In logistic regression, all combined blood inflammation indexes, barring PLR, were independently associated with the presence of IPF after adjusting for age, gender, body mass index and smoking status. Furthermore, significant associations between FVC% and NLR, LMR, SIRI and AISI, and between DLCO% and NLR, dNLR, LMR, SIRI and AISI, were observed. CONCLUSIONS: In conclusion, our data indicate significant alterations of combined blood cell count indexes of inflammation in IPF.

Systemic concentrations of asymmetric dimethylarginine (ADMA) in chronic obstructive pulmonary disease (COPD): state of the art.

Experimental evidence suggests that oxidative stress (OS) may increase the activity of arginine methylating enzymes that produce the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA). In addition, it is well documented that OS can significantly decrease the synthesis and/or activity of ADMA degrading enzymes, thus causing ADMA accumulation in biological fluids. Recent reports have focused on circulating methylated arginine concentrations in chronic obstructive pulmonary disease, a disease characterized by a significant increase in OS. This review discusses the results of these studies and the opportunities for further research in this area.

Blood global DNA methylation is decreased in non-severe chronic obstructive pulmonary disease (COPD) patients.

BACKGROUND: Alterations in global DNA methylation have been associated with oxidative stress (OS). Since chronic obstructive pulmonary disease (COPD) is characterized by increased oxidative stress we aimed to evaluate the levels of global DNA methylation in this patient group. METHODS: We assessed methylcytosine (mCyt) levels in DNA from blood collected in 43 COPD patients (29 with mild and 14 with moderate disease) and 43 age- and sex-matched healthy controls. RESULTS: DNA methylation was significantly lower in COPD patients vs. controls (4.20 ± 0.18% mCyt vs. 4.29 ± 0.18% mCyt, p = 0.02). Furthermore, DNA methylation in COPD patients with moderate disease was significantly lower than that in patients with mild disease (4.14 ± 0.15% mCyt vs. 4.23 ± 0.19% mCyt, p < 0.05). Univariate logistic regression analysis showed that lower DNA methylation levels were associated with presence of COPD (crude OR = 0.06, 95% CI 0.00 to 0.67, p = 0.023). This relationship remained significant after adjusting for several confounders (OR 0.03, 95% CI 0.00 to 0.67; p = 0.028). Receiver operating characteristics (ROC) curve analysis demonstrated the area under the curve of mCyt was 0.646, with 46.6% sensitivity and 79.1% specificity for presence of COPD. CONCLUSIONS: There were no significant correlations between methylation and OS indices. The presence and severity of COPD is associated with progressively lower DNA methylation in blood. However, this epigenetic alteration seems independent of oxidative stress.

Identification of the Main Intermediate Precursor of l-Ergothioneine Biosynthesis in Human Biological Specimens.

A capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) has been used to make a qualitative determination of hercynine-the main precursor of l-ergothioneine biosynthesis-in some key human biological specimens, such as urine, whole blood, plasma, and saliva. From semiquantitative analysis results, the highest concentrations of hercynine were detected in saliva and whole blood, whereas much lower concentrations were measured in urine and plasma. Whole blood was the biological matrix with the highest concentration of l-ergothioneine followed by plasma, saliva, and urine. The antioxidant effects attributed to l-ergothioneine, along with its peculiar antioxidant mechanism, offer a possible explanation for the presence of the hercynine, as well as its concentration, in the considered biological matrices.

Simultaneous determination of aromatic amino acids in human blood plasma by capillary electrophoresis with UV-absorption detection.

Phenylalanine, tyrosine, and tryptophan, also known as aromatic amino acids, are involved in many physiological and pathophysiological conditions and are indicative of the liver and kidney function. In this work, we describe a simple and accurate method for their simultaneous quantification, in a single capillary electrophoresis run. This method requires minimal sample manipulation, no derivatization procedures, and methyl tryptophan as internal standard. The human blood plasma sample was precipitated using sulfosalicylic acid and the supernatant was used for the analysis. All the analytes were baseline resolved within 16 min and detected at 200 nm using Tris phosphate 80 mmol/L at pH 1.4 as the background electrolyte. The proposed method showed good linearity (r = 0.998) and repeatability (intra-assay RSD < 2.78%, interassay RSD < 5.4%) for all the analytes. The limit of quantification was 13 µmol/L for phenylalanine and 5 µmol/L for tyrosine and tryptophan. The method suitability was tested measuring aromatic amino acids level in 20 chronic kidney disease patients at basal level and after simvastatin/ezetimibe treatment.

IC4: a new combined predictive index of mortality in idiopathic pulmonary fibrosis.

BACKGROUND: While a number of individual patient characteristics are associated with survival in idiopathic pulmonary fibrosis (IPF), their incorporation into combined indexes, such as the GAP index, has been shown to increase the predictive capacity. It is unknown whether the predictive capacity of GAP-derived indexes that also include anthropometric and exercise parameters is superior to the original instrument. METHODS: We tested the four-year survival predictive capacity of a modified, adimensional and multiplicative GAP index (IC4) that included percent forced vital capacity (FVC%), diffusing capacity of the lung for carbon monoxide (DLCO%), Body Mass Index (BMI), and six-minute walk distance (6MWD) in 90 IPF patients recruited from two centers in France and Italy. RESULTS: In ROC comparisons, the AUC of the IC4 (0.859, 95% CI 0.770-0.924 P<0.0001) was significantly higher than the AUCs of the individual components, their two-three component combinations, and the original GAP index, with 77% sensitivity and 89% specificity. Mean survival was 14.0±11.7, 23.2±12.7, 34.9±14.8, and 40.8±12.9 months, and survival rate was 0%, 14%, 39% and 73%, in IC4 quartile 1, 2, 3, and 4, respectively. CONCLUSIONS: The IC4, a combined non-dimensional index incorporating FVC%, DLCO%, BMI and 6MWD, provides superior capacity to predict mortality, when compared to its individual components, their other combinations, and the GAP index, in patients with IPF.

Serum Albumin Concentrations in Stable Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a progressive condition characterized by chronic airway inflammation and lung parenchyma damage. Systemic inflammation and oxidative stress also play a role in the pathogenesis of COPD. Serum albumin is a negative acute-phase protein with antioxidant effects and an important marker of malnutrition. The aim of this meta-analysis was to investigate differences in serum albumin concentrations between patients with stable COPD and non-COPD subjects. METHODS: A systematic search was conducted, using the terms "albumin" and "chronic obstructive pulmonary disease" or "COPD", in the electronic databases PubMed and Web of Science, from inception to May 2020. RESULTS: Twenty-six studies were identified on a total of 2554 COPD patients and 2055 non-COPD controls. Pooled results showed that serum albumin concentrations were significantly lower in COPD patients (standard mean difference, SMD = -0.50, 95% CI -0.67 to -0.32; p < 0.001). No significant differences were observed in SMD of serum albumin concentrations between COPD patients with forced expiratory volume in the 1st second (FEV1) < 50% and those with FEV1 > 50%. CONCLUSIONS: Our systematic review and meta-analysis showed that serum albumin concentrations are significantly lower in patients with stable COPD compared to non-COPD controls. This supports the presence of a deficit in systemic anti-inflammatory and antioxidant defense mechanisms in COPD.

Systematic Review and Meta-Analysis of the Blood Glutathione Redox State in Chronic Obstructive Pulmonary Disease.

The aim of this systematic review and meta-analysis was to assess the blood concentrations of the total and reduced forms of the low-molecular-weight antioxidant thiol glutathione (GSH) in chronic obstructive pulmonary disease (COPD) patients in comparison to healthy individuals. A literature search was conducted in the PubMed and Web of Science databases from inception until June 2020. In the 18 studies identified (involving a total of 974 COPD patients and 631 healthy controls), the pooled reduced GSH concentrations were significantly lower in patients with COPD than controls (SMD = -3.04, 95% CI = -4.42 to -1.67; p < 0.001). By contrast, the pooled total GSH concentrations were significantly higher in patients with COPD than controls (SMD = 0.42, 95% CI = 0.11 to 0.73; p = 0.009). Our meta-analysis showed that the blood concentrations of reduced GSH, even in the presence of higher total GSH concentrations, were significantly lower in patients with COPD when compared to healthy controls. This suggests that an impaired antioxidant defense system plays an important role in the pathogenesis of COPD.

Effects of Pirfenidone and Nintedanib on Markers of Systemic Oxidative Stress and Inflammation in Patients with Idiopathic Pulmonary Fibrosis: A Preliminary Report.

INTRODUCTION: In vitro evidence suggests that pirfenidone and nintedanib, approved agents for the treatment of idiopathic pulmonary fibrosis (IPF), exert anti-inflammatory and anti-oxidant effects. We aimed to investigate such effects in vivo in IPF patients. METHODS: Systemic circulating markers of oxidative stress [nuclear factor erythroid 2-related factor 2 (Nrf2), thiobarbituric acid- reactive substances (TBARS), homocysteine (Hcy), cysteine (Cys), asymmetric dimethylarginine (ADMA) and ADMA/Arginine ratio, glutathione (GSH), plasma protein -SH (PSH), and taurine (Tau)] and inflammation [Kynurenine (Kyn), Tryptophan (Trp) and Kyn/Trp ratio] were measured at baseline and after 24-week treatment in 18 IPF patients (10 treated with pirfenidone and 8 with nintedanib) and in 18 age- and sex-matched healthy controls. RESULTS: Compared to controls, IPF patients had significantly lower concentrations of reduced blood GSH (457 ± 73 µmol/L vs 880 ± 212 µmol/L, p < 0.001) and plasma PSH (4.24 ± 0.95 µmol/g prot vs 5.28 ± 1.35 µmol/g prot, p = 0.012). Pirfenidone treatment significantly decreased the Kyn/Trp ratio (0.030 ± 0.011 baseline vs 0.025 ± 0.010 post-treatment, p = 0.048) whilst nintedanib treatment significantly increased blood GSH (486 ± 70 µmol/L vs 723 ± 194 µmol/L, p = 0.006) and reduced ADMA concentrations (0.501 ± 0.094 vs. 0.468 ± 0.071 µmol/L, p = 0.024). CONCLUSION: pirfenidone and nintedanib exert beneficial effects on specific markers of oxidative stress and inflammation in IPF patients.

A Capillary Electrophoresis UV Detection-Based Method for Global Genomic DNA Methylation Assessment in Human Whole Blood.

Quantitative analysis of DNA methylation patterns is of special importance in several developmental and pathological situations. The development of simple and robust methods to assess DNA methylation is required to facilitate its measurement and interpretation in clinical practice. We describe a highly reproducible CE-UV method for the separation and detection of cytosine and methylcytosine, after formic acid hydrolysis of DNA extracted from human whole blood. Hydrolyzed samples were dried and successively dissolved with water and then injected into the capillary without sample derivatization procedures. The use of a run buffer containing 50 mmol/L BIS-TRIS propane (BTP) phosphate buffer at pH 3.25 and 60 mmol/L sodium acetate buffer at pH 3.60 (4:1, v/v) allowed a baseline analytes separation within 12 min. Precision tests indicated an elevated reproducibility with an inter-assay CV of 1.98%.

Plasma Proteomic Signatures in Early Chronic Obstructive Pulmonary Disease.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation and abnormal inflammatory response of the lungs to inhaled noxious particles or gases. We used a proteomic approach with 2-DE followed by MALDI TOF-MS analyses in order to identify potential biomarkers in the early stages of the disease: global initiative for chronic obstructive pulmonary disease (GOLD) stage mild and moderate. EXPERIMENTAL DESIGN: Blood plasma was collected from 43 patients with mild and moderate COPD as well as from 43 age- and sex-matched control subjects. Proteome analysis was based on 2D-Page followed by MALDI-TOF MS identifications. Validation was made on two significant proteins by western blotting. RESULTS: The analyses revealed 29 between-group differences in expressed spots, belonging to 20 unique proteins. These proteins are involved in inflammation (haptoglobin, Ig alpha-1 chain C), blood coagulation and complement pathways (prothrombin, complement 4-B, ApoH), oxidative stress (ceruloplasmin, vitamin D binding protein, and serotransferrin), and lipoprotein/lipid metabolism (apolipoprotein A-I, and apolipoprotein E). CONCLUSION AND CLINICAL RELEVANCE: These results indicate that specific proteomic signatures can be detected and useful in terms of treatment selection and in early COPD patient monitoring.

Increased kynurenine plasma concentrations and kynurenine-tryptophan ratio in mild-to-moderate chronic obstructive pulmonary disease patients.

AIM: Since an increase in kynurenine (Kyn) plasma concentrations has been proposed as marker of immune system activation, we studied the associations between the Kyn levels and presence and severity of chronic obstructive pulmonary disease (COPD). METHODS & RESULTS: Plasma Kyn, tryptophan (Trp) and Kyn/Trp ratio were measured in 43 COPD patients with clinically defined mild (n = 29) or moderate (n = 14) disease and 43 age- and sex-matched healthy controls. When compared with controls, COPD patients had significantly higher plasma Kyn concentrations and Kyn/Trp ratios. In multiple logistic regression analysis, after adjusting for clinical and demographic confounders, the Kyn/Trp ratio was independently associated with COPD severity. DISCUSSION & CONCLUSION: Kyn and Kyn/Trp ratio might represent a new, sensitive, biomarker of systemic inflammation in COPD patients.

Evaluation of Global Genomic DNA Methylation in Human Whole Blood by Capillary Electrophoresis UV Detection.

Alterations in global DNA methylation are implicated in various pathophysiological processes. The development of simple and quick, yet robust, methods to assess DNA methylation is required to facilitate its measurement and interpretation in clinical practice. We describe a highly sensitive and reproducible capillary electrophoresis method with UV detection for the separation and detection of cytosine and methylcytosine, after formic acid hydrolysis of DNA extracted from human whole blood. Hydrolysed samples were dried and resuspended with water and directly injected into the capillary without sample derivatization procedures. The use of a run buffer containing 50 mmol/L BIS-TRIS propane (BTP) phosphate buffer at pH 3.25 and 60 mmol/L sodium acetate buffer at pH 3.60 (4 : 1, v/v) allowed full analyte identification within 11 min. Precision tests indicated an elevated reproducibility with an interassay CV of 1.98% when starting from 2 µg of the extracted DNA. The method was successfully tested by measuring the DNA methylation degree both in healthy volunteers and in reference calf thymus DNA.

Effect of cholesterol lowering treatment on plasma markers of endothelial dysfunction in chronic kidney disease.

The elevated cardiovascular morbidity and mortality in chronic kidney disease (CKD) is linked with endothelial dysfunction secondary to the pro-inflammatory and pro-oxidative state typical of this pathology. In consideration of the well-known pleiotropic effect of statins, we investigated the effect of cholesterol lowering treatment on endothelial dysfunction markers (MED), asymmetric dimethylarginine (ADMA), vascular cell (VCAM) and intercellular (ICAM) adhesion molecule. Plasma MED concentrations, inflammation and oxidative stress indices [Kynurenine/Tryptophan (Kyn/Trp) ratio, malondialdehyde (MDA) and allantoin/uric acid (All/UA) ratio] were measured in 30 CKD patients randomized to three cholesterol lowering regimens for 12 months (simvastatin 40mg/day, ezetimibe/simvastatin 10/20mg/day, or ezetimibe/simvastatin 10/40mg/day). Treatment significantly reduced ADMA concentrations in all patients [0.694µmol/L (0.606-0.761) at baseline vs. 0.622µmol/L (0.563-0.681) after treatment, p<0.001]. ADMA reduction was paralleled by a significant decrease of MDA, All/AU ratio and Kyn/Trp ratio, but not VCAM and ICAM plasma concentrations. Cholesterol lowering treatment was associated with a significant reduction in plasma ADMA concentrations in CKD patients. This might be mediated by reduced oxidative stress and inflammation.

Simultaneous determination of the main amino thiol and thione in human whole blood by CE and LC.

BACKGROUND: Two precolumn fluorescence derivatization procedures by two different sulfhydryl-reactive iodoacetyl reagents were established to measure simultaneously glutathione and l-ergothioneine in human whole blood by means of CE and LC. MATERIALS & METHODS: Separations were achieved in <5 min on a reverse-phase column (100 mm × 4.6 mm Zorbax Eclipse Plus C18 3.5 µm) for LC analysis, and on an uncoated fused-silica capillary (60 cm × 50 µm) for CE analysis, monitoring the fluorescence of derivatives. RESULTS: Performance of the assays was good in terms of linearity, recovery, intra- and inter-day precision and LOD and LOQ. CONCLUSION: This novel approach allows rapid assessment of circulating glutathione and l-ergothioneine concentrations for clinical and research purposes.

Effects of Ramipril and Telmisartan on Plasma Concentrations of Low Molecular Weight and Protein Thiols and Carotid Intima Media Thickness in Patients with Chronic Kidney Disease.

Hypertension, a common feature in chronic kidney disease (CKD), is an independent risk factor for CKD progression and cardiovascular disease. Although inhibitors of the renin-angiotensin system (RAS) exert salutary effects on blood pressure control and proteinuria in CKD patients, their activity towards traditional and novel oxidative markers is largely unknown. We studied the effects of 6-month treatment with telmisartan versus a combination of telmisartan and ramipril on plasma concentrations of low molecular mass (LMW, including homocysteine and cysteine) and protein thiols (PSH) plasma concentration and their relationships with carotid intima media thickness (IMT), in 24 hypertensive CKD patients (age 60 ± 12 years, 8 females and 16 males). Pretreatment PSH concentrations were independently associated with IMT (r = -0.42, p = 0.039). Neither treatment affected plasma LMW thiols, in both reduced and total form. By contrast, both treatments increased PSH plasma concentrations and reduced IMT, although significant differences were only observed in the combined treatment group. Our results suggest that the beneficial effects of combined RAS inhibitor treatment on IMT in hypertensive CKD patients may be mediated by a reduction of oxidative stress markers, particularly PSH.

Arginines Plasma Concentration and Oxidative Stress in Mild to Moderate COPD.

BACKGROUND: Elevated plasma concentrations of the endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) have been observed in respiratory conditions such as asthma and cystic fibrosis. Since oxidative stress has been shown to increase the activity of arginine methylating enzymes, hence increased ADMA synthesis, and to reduce ADMA degrading enzymes, hence increased ADMA concentrations, we assessed methylated arginines concentrations in chronic obstructive pulmonary disease (COPD), a disease characterized by increased oxidative stress. METHODS: Plasma arginine, ADMA and symmetric dimethylarginine (SDMA), oxidative stress markers (thiobarbituric acid reactive substances, TBARS, and plasma proteins SH, PSH) and antioxidants (taurine and paraoxonase 1, PON1, activity) were measured in 43 COPD patients with mild (n = 29) or moderate (n = 14) disease and 43 age- and sex-matched controls. RESULTS: TBARS significantly increased with COPD presence and severity (median 2.93 vs 3.18 vs 3.64 µmol/L, respectively in controls, mild and moderate group, p<0.0001 by ANOVA) whereas PSH decreased (6.69±1.15 vs 6.04±0.85 vs 5.33±0.96 µmol/gr prot, p<0.0001 by ANOVA). Increased ADMA/arginine ratio, primarily due to reduced arginine concentrations, was also observed with COPD presence and severity (median 0.0067 vs 0.0075 vs 0.0100, p<0.0001 by ANOVA). In multiple logistic regression analysis, only TBARS (OR 0.44, 95% CI 0.25-0.77; p = 0.0045) and ADMA/Arginine ratio (OR 1.72, 95% CI 2.27-13.05; p = 0.02) were independently associated with COPD severity. CONCLUSION: COPD presence and severity are associated with increased oxidative stress and alterations in arginine metabolism. The reduced arginine concentrations in COPD may offer a new target for therapeutic interventions increasing arginine availability.