Myeloperoxidase in human lung lavage. I. A marker of local neutrophil activity

Identification of pivotal genes and regulatory networks associated with atherosclerotic carotid artery stenosis based on comprehensive bioinformatics analysis and machine learning

Objective

Bioinformatics methods were applied to investigate the pivotal genes and regulatory networks associated with atherosclerotic carotid artery stenosis (ACAS) and provide new insights for the treatment of this disease.

Methods

The study utilized five ACAS datasets (GSE100927, GSE11782, GESE28829, GSE41571, and GSE43292) downloaded from the NCBI GEO database. The first four datasets were combined as the training set (n = 99), while GSE43292 (n = 64) was used as the validation set. Difference analysis and functional enrichment analysis were then performed on the training set. The pathogenic targets of ACAS were screened by protein-protein interaction networks and MCODE analyses, combined with three machine learning algorithms. The results were next verified by analysis of inter-group differences and ROC curve analysis. Next, immune-related function and immune cell correlation analyses were performed, and plaques of human ACAS were applied to verify the results via immunohistochemistry (IH) and immunofluorescence (IF). Finally, the competing endogenous RNAs (ceRNA) and transcription factors (TFs) regulatory networks of the characterized genes were constructed.

Results

A total of 177 differentially expressed genes were identified, including 67 genes downregulated and 110 genes upregulated. Gene set enrichment analysis revealed that five pathways were active in the experimental group, including xenograft rejection, autoimmune thyroid disease, graft-versus-host disease, leishmaniasis infection, and lysosomes. Four key genes were identified, with C3AR1 being upregulated and FBLN5, PPP1R12A, and TPM1 being downregulated. The analysis of inter-group differences demonstrated that the four characterized genes were differentially expressed in both the control and experimental groups. The ROC analysis showed that they had high AUC values in both the training and validation sets. Therefore, a predictive ACAS patient nomogram model based on the screened genes was established. Correlation analysis revealed a positive correlation between C3AR1 expression and neutrophils, which was further validated in IH and IF. One or multiple lncRNAs may compete with the characterized genes for binding miRNAs. Additionally, each characterized gene interacts with multiple TFs.

Conclusion

Four pivotal genes were screened, and relevant ceRNA and TFs were predicted. These molecules may exert a crucial role in ACAS and serve as potential biomarkers and therapeutic targets.

Factors Influencing Venous Remodeling in the Development of Varicose Veins of the Lower Limbs

One of the early symptoms of chronic venous disease (CVD) is varicose veins (VV) of the lower limbs. There are many etiological environmental factors influencing the development of chronic venous insufficiency (CVI), although genetic factors and family history of the disease play a key role. All these factors induce changes in the hemodynamic in the venous system of the lower limbs leading to blood stasis, hypoxia, inflammation, oxidative stress, proteolytic activity of matrix metalloproteinases (MMPs), changes in microcirculation and, consequently, the remodeling of the venous wall. The aim of this review is to present current knowledge on CVD, including the pathophysiology and mechanisms related to vein wall remodeling. Particular emphasis has been placed on describing the role of inflammation and oxidative stress and the involvement of extracellular hemoglobin as pathogenetic factors of VV. Additionally, active substances used in the treatment of VV were discussed.

Anti-interferon-α receptor 1 antibodies attenuate inflammation and organ injury following hemorrhagic shock

BACKGROUND

Hemorrhagic shock (HS) is a life-threatening condition resulting from rapid and significant loss of intravascular volume, leading to hemodynamic instability and death. Inflammation contributes to the multiple organ injury in HS. Type I interferons (IFNs), such as IFN-α and IFN-β, are a family of cytokines that regulate the inflammatory response through binding to IFN-α receptor (IFNAR) which consists of IFNAR1 and IFNAR2 chains. We hypothesized that type I IFNs provoke inflammation and worsen organ injury in HS.

METHODS

Male C57BL/6 mice (20-25 g) underwent hemorrhage by controlled bleeding via the femoral artery to maintain a mean arterial pressure of 27 ± 2.5 mm Hg for 90 minutes, followed by resuscitation for 30 minutes with two times shed blood volume of Ringer's lactate solution containing 1 mg/kg body weight of anti-IFNAR1 antibody (Ab) or control isotype-matched IgG (IgG). Blood and tissue samples were collected at 20 hours after the resuscitation for various analyses.

RESULTS

The expression of IFN-α and IFN-β mRNAs was significantly elevated in lungs and liver of the mice after HS. The IFNAR1-Ab treatment significantly decreased serum levels of organ injury markers lactate dehydrogenase and aspartate aminotransferase, as well as improved the integrity of lung and liver morphology, compared to the IgG control. The protein levels of proinflammatory cytokines TNF-α and IL-6, and mRNA expression of proinflammatory chemokines monocyte chemoattractant protein (MCP)-1, MCP-2, macrophage inflammatory protein 2 (MIP-2), and keratinocyte cytokine (KC) in the lungs of the HS mice were significantly decreased after treated with IFNAR1-Ab. Moreover, the myeloperoxidase activity and number of apoptotic cells in the lungs of HS mice treated with IFNAR1-Ab were decreased in comparison to the IgG control.

CONCLUSION

Administration of IFNAR1-Ab reduces inflammation and tissue injury. Thus, type I IFN signaling may be a potential therapeutic target for mitigating organ dysfunction in patients suffering from HS.

STUDY TYPE

Translational animal model.

Deoxyribonuclease Reduces Tissue Injury and Improves Survival After Hemorrhagic Shock

BACKGROUND

Hemorrhagic shock (HS) caused by rapid loss of a large amount of blood is the leading cause of early death after severe injury. When cells are damaged during HS, many intracellular components including DNA are released into the circulation and function as endogenous damage-associated molecular patterns (DAMPs) that can trigger excessive inflammatory response and subsequently multiple organ dysfunction. We hypothesized that the administration of deoxyribonuclease I (DNase I) could reduce cell-free DNA and attenuate tissue damage in HS.

METHODS

Eight-week-old male C57BL/6 mice underwent HS by controlled bleeding from the femoral artery for 90 min, followed by resuscitation with Ringer's lactate solution (vehicle) or DNase I (10 mg/kg BW).

RESULTS

At 20 h after HS, serum levels of cell-free DNA were increased by 7.6-fold in the vehicle-treated HS mice compared with sham, while DNase I reduced its levels by 47% compared with the vehicle group. Serum levels of tissue injury markers (lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase) and proinflammatory cytokine interleukin 6 were significantly reduced in the DNase I-treated mice. In the lungs, messenger RNA levels of proinflammatory cytokines (interleukin 6 and interleukin 1 β), chemoattractant macrophage inflammatory protein - 2, and myeloperoxidase activity were significantly decreased in HS mice after DNase I. Finally, DNase I significantly improved the 10-day survival rate in HS mice.

CONCLUSIONS

Administration of DNase I attenuates tissue damage and systemic and lung inflammation, leading to improvement of survival in HS mice. Thus, DNase I may potentially serve as an adjunct therapy for managing patients with HS.

Hepatoma-derived growth factor participates in Helicobacter Pylori-induced neutrophils recruitment, gastritis and gastric carcinogenesis

Helicobacter pylori (Hp) infection and overexpression of hepatoma-derived growth factor (HDGF) are involved in gastric carcinogenesis. However, the relationship between Hp-induced gastric diseases and HDGF upregulation is not yet completely clear. This study aimed to elucidate the role of HDGF in Hp-induced gastric inflammation and carcinogenesis. HDGF expression in gastric biopsy and serum from patients was analyzed by immunohistochemical and ELISA analysis, respectively. Hp and gastric cells coculture system was employed to delineate the mechanism underlying HDGF overexpression during Hp infection. The gastric pathologies of wild type and HDGF knockout mice after Hp infection were investigated by immunohistochemical, immunoblot, and immunofluorescence analyses. HDGF level was significantly elevated in patients with Hp infection or intestinal metaplasia (IM, a precancerous lesion), and HDGF overexpression was positively correlated with Hp load, IM, and neutrophil infiltration in gastric biopsy. Consistently, patients with Hp infection or IM had significantly higher serum HDGF level. By using coculture assay, Hp infection led to HDGF upregulation and secretion in gastric cells. In mice model, HDGF ablation significantly suppressed the Hp-induced neutrophil infiltration and inflammatory TNF-α/COX-2 signaling, thereby relieving the tissue damage in stomach. This was further supported by that recombinant HDGF (rHDGF) stimulated the differentiation/chemotaxis of cultured neutrophils and oncogenic behaviors of gastric cells. Time series studies showed that Hp infection elicited an inflammatory TNF-α/HDGF/COX-2 cascade in stomach. HDGF secretion by Hp infection promotes the neutrophils infiltration and relays Hp-induced inflammatory signaling. Thus, HDGF may constitute a novel diagnostic marker and therapeutic target for Hp-induced gastritis and carcinogenesis.

The human lung mucosa drives differential Mycobacterium tuberculosis infection outcome in the alveolar epithelium

Mycobacterium tuberculosis (M.tb) is deposited into the alveolus where it first encounters the alveolar lining fluid (ALF) prior contacts host cells. We demonstrated that M.tb-exposure to human ALF alters its cell surface, driving better M.tb infection control by professional phagocytes. Contrary to these findings, our results with non-professional phagocytes alveolar epithelial cells (ATs) define two distinct subsets of human ALFs; where M.tb exposure to Low (L)-ALF or High(H)-ALF results in low or high intracellular bacterial growth rates in ATs, respectively. H-ALF exposed-M.tb growth within ATs was independent of M.tb-uptake, M.tb-trafficking, and M.tb-infection induced cytotoxicity; however, it was associated with enhanced bacterial replication within LAMP-1⁺/ABCA1⁺ compartments. H-ALF exposed-M.tb infection of ATs decreased AT immune mediator production, decreased AT surface adhesion expression, and downregulated macrophage inflammatory responses. Composition analysis of H-ALF vs. L-ALF showed H-ALF with higher protein tyrosine nitration and less functional ALF-innate proteins important in M.tb pathogenesis. Replenishment of H-ALF with functional ALF-innate proteins reversed the H-ALF-M.tb growth rate to the levels observed for L-ALF-M.tb. These results indicate that dysfunctionality of innate proteins in the H-ALF phenotype promotes M.tb replication within ATs, while limiting inflammation and phagocyte activation, thus potentiating ATs as a reservoir for M.tb replication and survival.

PYR-41, A Ubiquitin-Activating Enzyme E1 Inhibitor, Attenuates Lung Injury in Sepsis

During sepsis, systemic inflammation is observed and is associated with multiple organ failure. Activation of NF-κB is crucial for inducing inflammation, which is controlled by degradation of inhibitor molecules (IκB). The ubiquitination proteasome pathway is responsible for the regulation of protein turnover. In this study, we hypothesized that administration of 4[4-(5-nitro-furan-2-ylmethylene)-3, -dioxo-pyrazolidin-1-yl]-benzoic acid ethyl ester (PYR-41), an inhibitor of ubiquitination, could reduce inflammation and organ injury in septic mice. PYR-41 prevented the reduction of IκB protein levels and inhibited release of tumor necrosis factor (TNF)-α in mouse macrophage RAW264.7 cells at 4 h after lipopolysaccharide stimulation dose-dependently. Male C57BL/6 mice were subjected to cecal ligation and puncture (CLP) to induce sepsis. PYR-41 (5 mg/kg) or dimethyl sulfoxide in saline (vehicle) was injected intravenously immediately after CLP. At 20 h after CLP, PYR-41 treatment significantly decreased serum levels of proinflammatory cytokines (TNF-α, interleukin [IL]-1β, and IL-6) and organ injury markers (aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase). PYR-41 significantly improved microscopic structure, and reduced myeloperoxidase activity, number of apoptotic cells and caspase-3 degradation in the lungs of septic mice. The reduced protein levels of IκB in the lungs after CLP were restored by PYR-41 treatment. PYR-41 inhibited the expression of cytokines (IL-1β and IL-6), chemokines (keratinocyte-derived chemokine and macrophage inflammatory protein 2), and inflammatory mediators (cyclooxygenase-2 and inducible nitric oxide synthase) in the lungs of septic mice. Importantly, PYR-41 significantly increased 10-day survival in septic mice from 42% to 83%. Therefore, targeting ubiquitination by PYR-41 to inhibit NF-κB activation may represent a potential strategy of sepsis therapeutics.

Inhibition of ubiquitin-activating enzyme protects against organ injury after intestinal ischemia-reperfusion

Intestinal ischemia-reperfusion (I/R) occurs in various clinical settings, such as transplantation, acute mesenteric arterial occlusion, trauma, and shock. I/R injury causes severe systemic inflammation, leading to multiple organ dysfunction associated with high mortality. The ubiquitin proteasome pathway has been indicated in the regulation of inflammation, particularly through the NF-κB signaling pathway. PYR-41 is a small molecular compound that selectively inhibits ubiquitin-activating enzyme E1. A mouse model of intestinal I/R injury by clamping the superior mesenteric artery for 45 min was performed to evaluate the effect of PYR-41 treatment on organ injury and inflammation. PYR-41 was administered intravenously at the beginning of reperfusion. Blood and organ tissues were harvested at 4 h after reperfusion. PYR-41 treatment improved the morphological structure of gut and lung after I/R, as judged by hematoxylin and eosin staining. It also reduced the number of apoptotic terminal deoxynucleotidyl transferase dUTP nick end-labeling-positive cells and caspase-3 activity in the organs. PYR-41 treatment decreased the expression of proinflammatory cytokines IL-6 and IL-1β as well as chemokines keratinocyte chemoattractant and macrophage inflammatory protein-2 in the gut and lung, which leads to inhibition of neutrophils infiltrating into these organs. The serum levels of IL-6, aspartate aminotransferase, and lactate dehydrogenase were reduced by the treatment. The IκB degradation in the gut increased after I/R was inhibited by PYR-41 treatment. Thus, ubiquitination may be a potential therapeutic target for treating patients suffering from intestinal I/R. NEW & NOTEWORTHY Excessive inflammation contributes to organ injury from intestinal ischemia-reperfusion (I/R) in many clinical conditions. NF-κB signaling is very important in regulating inflammatory response. In an experimental model of gut I/R injury, we demonstrate that administration of a pharmacological inhibitor of ubiquitination process attenuates NF-κB activation, leading to reduction of inflammation, tissue damage, and apoptosis in the gut and lungs. Therefore, ubiquitination process may serve as a therapeutic target for treating patients with intestinal I/R injury.

Evaluation of oxidative stress in caprine bronchoalveolar lavage fluid of pneumonic and normal lungs

Research in the area of oxidative stress in pneumonic pathology still requires attention in small ruminants especially with the use of bronchoalveolar lavage (BAL) which may be a more sensitive indicator of respiratory diseases than blood. This investigation evaluates the role of oxidative stress in the pathogenesis of caprine pneumonia using BAL fluid (BALf) from healthy and pneumonic goats. A BALf from 192 goats (whose pneumonic histopathology had been characterized using standard techniques) was biochemically assayed for anti-oxidants and pro-oxidants. Malondialdehyde (MDA), hydrogen peroxide generation (H₂O₂), myeloperoxidase (MPO) and reduced glutathione (GSH) contents were measured to assess free radical activity in the BALf. Superoxide dismutase (SOD), Glutathione transferase (GST) and Glutathione peroxidase (GPx) activity were also determined colourimetrically. There were significant increases in the BALf supernatant of MDA, H₂O₂ and MPO with decreases in GSH level and SOD activity in the pneumonic goats (P < 0.05). There was also significant correlation of BALf oxidative assay to the type and severity of pneumonia. The levels of MDA, H₂O_2, and MPO increased significantly (P < 0.05) in bronchopneumonia and bronchointerstitial pneumonia than other pneumonic conditions and normal lungs. The management of caprine pneumonia should often incorporate antioxidant supplementation to correct the imbalance in pro-oxidant and anti-oxidant levels.

Effects of doxycycline on local and systemic inflammation in stable COPD patients, a randomized clinical trial

Neutrophilic inflammation plays a causal role in Chronic Obstructive Pulmonary Disease (COPD). Neutrophil derived myeloperoxidase(MPO) matrix metalloproteinases(MMP's), and elastases are thought to contribute to the perpetuation of the disease. The tetracycline analogue doxycycline has been shown to inhibit neutrophil-mediated inflammation. It was thus reasoned that doxycycline may attenuate neutrophil-mediated inflammation in COPD.

METHODS

In this double blind randomized controlled trial the effect of a 3-week course of doxycycline on sputum and systemic inflammatory parameters was evaluated in stable COPD patients. In order to exclude inflammation by bacterial colonisation patients must have 2 negative sputum cultures in the previous year. The effect of doxycycline treatment on inflammatory markers (TNF-α, IL-1β and IL-6) and neutrophil specific markers in sputum (MPO, MMP's, and IL-8) and serum C-reactive protein was evaluated. Sputum was obtained by sputum induction with hypertonic saline.

RESULTS

A total of 41 patients were included. Ten patients were excluded as they were not able to produce sputum at the first or second visit. Baseline characteristics were similar in the two groups. In the remaining patients doxycycline did not influence sputum MPO concentrations. Also MMP-8 and 9, IL-6 and IL-8 concentrations as well as lung function parameters were not affected by doxycycline. Systemic inflammation by means of CRP was also not influenced by doxycycline.

CONCLUSION

A three week course of doxycycline did not influence MPO sputum levels nor any of the other inflammatory sputum and systemic markers.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00857038 URL: clinicaltrials.gov.

Stimulation of Brain AMP-Activated Protein Kinase Attenuates Inflammation and Acute Lung Injury in Sepsis

Sepsis and septic shock are enormous public health problems with astronomical financial repercussions on health systems worldwide. The central nervous system (CNS) is closely intertwined in the septic process but the underlying mechanism is still obscure. AMP-activated protein kinase (AMPK) is a ubiquitous energy sensor enzyme and plays a key role in regulation of energy homeostasis and cell survival. In this study, we hypothesized that activation of AMPK in the brain would attenuate inflammatory responses in sepsis, particularly in the lungs. Adult C57BL/6 male mice were treated with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR, 20 ng), an AMPK activator, or vehicle (normal saline) by intracerebroventricular (ICV) injection, followed by cecal ligation and puncture (CLP) at 30 min post-ICV. The septic mice treated with AICAR exhibited elevated phosphorylation of AMPKα in the brain along with reduced serum levels of aspartate aminotransferase, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), compared with the vehicle. Similarly, the expressions of TNF-α, IL-1β, keratinocyte-derived chemokine and macrophage inflammatory protein-2 as well as myeloperoxidase activity in the lungs of AICAR-treated mice were significantly reduced. Moreover, histological findings in the lungs showed improvement of morphologic features and reduction of apoptosis with AICAR treatment. We further found that the beneficial effects of AICAR on septic mice were diminished in AMPKα2 deficient mice, showing that AMPK mediates these effects. In conclusion, our findings reveal a new functional role of activating AMPK in the CNS to attenuate inflammatory responses and acute lung injury in sepsis.

[Genetic and biochemical mechanisms of involvement of antioxidant defense enzymes in the development of bronchial asthma]

In the present review we have analyzed and summarized recent literature data on genetic and biochemical mechanisms responsible for involvement of antioxidant defense enzymes in the etiology and pathogenesis of bronchial asthma. It has been shown that the mechanisms of asthma development are linked with genetically determined abnormalities in the functioning of antioxidant defense enzymes. These alterations are accompanied by a systemic imbalance between oxidative and anti-oxidative reactions with the shift of the redox state toward increased free radical production and oxidative stress, a key element in the pathogenesis of bronchial asthma.

Pyocyanina contributory factor in haem acquisition and virulence enhancement of Porphyromonas gingivalis in the lung [corrected]

Several recent studies show that the lungs infected with Pseudomonas aeruginosa are often co-colonised by oral bacteria including black-pigmenting anaerobic (BPA) Porphyromonas species. The BPAs have an absolute haem requirement and their presence in the infected lung indicates that sufficient haem, a virulence up-regulator in BPAs, must be present to support growth. Haemoglobin from micro-bleeds occurring during infection is the most likely source of haem in the lung. Porphyromonas gingivalis displays a novel haem acquisition paradigm whereby haemoglobin must be firstly oxidised to methaemoglobin, facilitating haem release, either by gingipain proteolysis or capture via the haem-binding haemophore HmuY. P. aeruginosa produces the blue phenazine redox compound, pyocyanin. Since phenazines can oxidise haemoglobin, it follows that pyocyanin may also facilitate haem acquisition by promoting methaemoglobin production. Here we show that pyocyanin at concentrations found in the CF lung during P. aeruginosa infections rapidly oxidises oxyhaemoglobin in a dose-dependent manner. We demonstrate that methaemoglobin formed by pyocyanin is also susceptible to proteolysis by P. gingivalis Kgp gingipain and neutrophil elastase, thus releasing haem. Importantly, co-incubation of oxyhaemoglobin with pyocyanin facilitates haem pickup from the resulting methemoglobin by the P. gingivalis HmuY haemophore. Mice intra-tracheally challenged with viable P. gingivalis cells plus pyocyanin displayed increased mortality compared to those administered P. gingivalis alone. Pyocyanin significantly elevated both methaemoglobin and total haem levels in homogenates of mouse lungs and increased the level of arginine-specific gingipain activity from mice inoculated with viable P. gingivalis cells plus pyocyanin compared with mice inoculated with P. gingivalis only. These findings indicate that pyocyanin, by promoting haem availability through methaemoglobin formation and stimulating of gingipain production, may contribute to virulence of P. gingivalis and disease severity when co-infecting with P. aeruginosa in the lung.

Dietary advanced glycation end-products, its pulmonary receptor, and high mobility group box 1 in aspiration lung injury

BACKGROUND

Gastric aspiration is a significant cause of acute lung injury and acute respiratory distress syndrome. Environmental risk factors, such as a diet high in proinflammatory advanced glycation end-products (AGEs), may render some patients more susceptible to lung injury after aspiration. We hypothesized that high dietary AGEs increase its pulmonary receptor, RAGE, producing an amplified pulmonary inflammatory response in the presence of high mobility group box 1 (HMGB1), a RAGE ligand and an endogenous signal of epithelial cell injury after aspiration.

MATERIALS AND METHODS

CD-1 mice were fed either a low AGE or high AGE diet for 4 wk. After aspiration injury with acidified small gastric particles, bronchoalveolar lavage and whole-lung tissue samples were collected at 5 min, 1 h, 5 h, and 24 h after injury. RAGE, soluble RAGE (sRAGE), HMGB1, cytokine and chemokine concentrations, albumin levels, neutrophil influx, and lung myeloperoxidase activity were measured.

RESULTS

We observed that high AGE-fed mice exhibited greater pulmonary RAGE levels before aspiration and increased bronchoalveolar lavage sRAGE levels after aspiration compared with low AGE-fed mice. Lavage HMGB1 levels rose immediately after aspiration, peaking at 1 h, and strongly correlated with sRAGE levels in both dietary groups. High AGE-fed mice demonstrated higher cytokine and chemokine levels with increased pulmonary myeloperoxidase activity over 24 h versus low AGE-fed mice.

CONCLUSIONS

This study indicates that high dietary AGEs can increase pulmonary RAGE, augmenting the inflammatory response to aspiration in the presence of endogenous damage signals such as HMGB1.

Tetomilast attenuates elastase-induced pulmonary emphysema through inhibition of oxidative stress in rabbits

Tetomilast was originally identified as a potent inhibitor of superoxide production in human neutrophils, and is of interest because it may relieve oxidative stress related to chronic obstructive pulmonary disease (COPD). Our objective was to determine whether tetomilast effectively protects against the development of porcine pancreatic elastase (PPE)-induced emphysema in rabbits. Rabbits were divided into three groups (sham n=19, PPE n=19, PPE/Tetomilast n=18). The rabbits were once daily orally administered vehicle solution or tetomilast 5 d/week for 4 weeks before the PPE instillation. We compared pulmonary function, inflammatory cell infiltration, oxidative stress, and the incidences of apoptosis among the three groups. Tetomilast suppressed PPE-induced increases in the incidence of apoptosis and the production of 8-hydroxy-deoxyguanosine (8-OHdG) in lung tissues. PPE-instilled rabbits treated with tetomilast showed significantly less mean linear intercept and significantly better pulmonary function than rabbits administered PPE alone. Tetomilast may inhibit the development of emphysema by attenuating pulmonary inflammation and apoptosis caused by PPE-induced oxidative stress.

Common genetic variants in the myeloperoxidase and paraoxonase genes and the related cancer risk: a review

Modern approaches in health care are moving toward the model of "personalized medicine." Today, current research in molecular biology and medicine is focused on developing genomic markers with predictive, therapeutic, and prognostic significance. One of the most widespread and significant genomic markers is the single nucleotide polymorphism (SNP), which represents a variation in DNA sequence when a single nucleotide differs between members of a biological species or paired chromosomes in an individual. Antioxidant defense enzymes break down dangerous reactive compounds, called reactive oxygen species, and prevent DNA strand from carcinogen-specific mutations. It is well known that inherited variations in genes that encode antioxidant defense enzymes may modulate individual susceptibility to cancer. In our previous study we have determined the predictive significance of several SNPs of superoxide dismutase (SOD) and glutathione peroxidase gene families in the context of cancer risk. The present review includes a summary and discussion of the current findings evaluating the role of SNPs of the myeloperoxidase (MPO) and paraoxanase (PON) genes in cancer occurrence and development. We suggest that rs2333227 (MPO_ -463G/A) and rs854560 polymorphisms have a great predictive significance; they could probably be utilized as cancer predictors in the future. Also, we recommend further in-depth research for rs11079344 (MPO), rs8178406 (MPO), rs2243828 (MPO), rs662 (PON1), rs705379 (PON1), and PON1_304A/G polymorphisms. These SNPs may become significant cancer-associated biomarkers.

Delayed asthmatic response to bronchial challenge with allergen-mediators, eicosanoids, eosinophil and neutrophil constituents in the blood and urine

BACKGROUND

In patients with allergic bronchial asthma, different immunologic mechanisms may participate and lead to different types of asthmatic response to allergen challenge, such as immediate/early (IAR/EAR), late (LAR) or delayed asthmatic response (DYAR).

OBJECTIVES

In 55 of 397 asthmatics, DYAR has been recorded (p < 0.001) and confirmed by repeated bronchial challenge with the same allergen (p < 0.001). DYAR began between 26 and 32 h, reached a maximum between 32 and 48 h and resolved within 56 h after the challenge. DYAR was associated with various clinical symptoms and diagnostic parameters having diverged from those recorded during the IARs/EARs and LARs.

METHODS

In 25 of 55 patients, repeated DYAR has been supplemented with the recording of leukotriene B(4) (LTB(4)), LTC(4), LTE(4), prostaglandin D(2) (PGD(2)), PGE(2), PGF(2)(α), thromboxane B(2), lipoxin A(4), eosinophil cationic protein, eosinophil-derived neurotoxin/eosinophil protein X, eosinophilic peroxidase, myeloperoxidase, histamine and tryptase in peripheral blood, and of LTC(4), thromboxane B(2), eosinophil-derived neurotoxin and 9α,11β-PGF(2) in urine, before and up to 72 h after the bronchial allergen challenge, by means of enzyme-linked immunoassay (ELISA/EIA) or ImmunoCAP.

RESULTS

DYAR was accompanied by a significant increase in the plasma concentrations of LTB(4) (p < 0.05) and myeloperoxidase (p < 0.05) at 24, 36 and 48 h after the challenge, whereas the plasma/serum or urine concentrations of the other factors did not demonstrate any significant changes (p > 0.05).

CONCLUSIONS

These results would indicate an active and prominent involvement of neutrophils, in addition to the previously demonstrated role of the Th1 lymphocytes, in the clinical DYAR.

Dampness and 2-ethyl-1-hexanol in floor construction of rehabilitation center: Health effects in staff

The authors evaluated changes of symptoms and biomarkers in health care staff (N = 18) for people with different physical dysfunctions and similarly in an external office control group in a nondamp building (N = 15). The first workplace had verified dampness in the floor construction, with formation of 2-ethyl-1-hexanol from water-based glue. Tear film break up time (BUT), nasal patency, biomarkers in nasal lavage (NAL), and dynamic spirometry were measured. Both buildings had low indoor air levels of CO2 (510 to 630 ppm), low levels of respirable particles (6 to 7 microg/m3) and formaldehyde (<5 microg/m3), and no indication of microbial growth. Pronounced increase of butanols and 2-ethyl-1-hexanol levels were found in the damp floor material samples, but very low air levels of 2-ethyl-1-hexanol. The staff had been previously exposed to floor construction with alkaline degradation of floor glue, as well as formation of 2-ethyl-1-hexanol. This led to an increase in their ocular, nasal, and respiratory symptoms, a decrease in nasal patency, and slight airway obstruction after 2 days of reexposure, possibly related to neutrophilic inflammation, after a 4-month exposure-free period.

Genetic variation of myeloperoxidase gene contributes to atopic asthma susceptibility: a preliminary association study in Russian population

BACKGROUND

Recently, we have shown that both antioxidant and oxidant genes are proper candidates for asthma susceptibility genes.

OBJECTIVES

In the present study we investigated whether a common polymorphism -463G > A in the promoter of myeloperoxidase (MPO) gene, an enzyme producing hypohalogenic oxidants, is associated with the risk of bronchial asthma.

METHODS

We studied 429 unrelated Russian subjects including 215 asthmatic patients and 214 sex- and age-matched healthy controls from Central Russia. The genotyping of the polymorphism -463G > A in the MPO gene was performed by the polymerase chain reaction and the restriction fragment length polymorphism assays.

RESULTS

It was found that a carriage of a -463A allele is associated with decreased risk of asthma (OR 0.64 95%CI 0.44-0.91, p = 0.013). Furthermore, variant genotypes (-463GA + AA) of the MPO gene were associated with decreased risk of asthma (OR adjusted by age, gender, and immunoglobulin E (IgE) level was 0.63 95%CI 0.42-0.95), but at a borderline statistical significance (Bonferroni corrected p = 0.017). Further analysis revealed that both a -463A allele and the -463GA/AA genotypes are significantly associated with decreased risk of atopic asthma (p = 0.01). No association of the -463G > A polymorphism of the MPO gene with non-atopic asthma has been revealed. We also found that the allele -463A (OR = 0.47 95%CI 0.27-0.81, p = 0.01) and the -463GA + AA genotypes (OR 0.43 95%CI 0.24-0.78, p = 0.005) are significantly associated with decreased risk of late-onset atopic asthma (the disease onset after 30 years). No association of both allele and genotypes of the polymorphism -463G > A of the MPO gene with early-onset of atopic and non-atopic asthma (the disease before 30 years) was seen.

CONCLUSIONS

The results of this study provide novel insights into pathogenesis of bronchial asthma. We put forward a suggestion about a possible mechanism by which the -463G > A polymorphism of the MPO gene is involved into pathogenesis of asthma.

Myeloperoxidase-mediated lipoprotein carbamylation as a mechanistic pathway for atherosclerotic vascular disease

There is an emerging and significant body of research that suggests that MPO (myeloperoxidase) may be a critical mediator in dysfunctional lipoprotein formation and, hence, atherogenic initiation and progression. MPO is a haem peroxidase found in leucocytes and is abundant in macrophages surrounding atherosclerotic lesions. Several lines of evidence support the role of MPO-mediated carbamylation of proteins in atherogenesis. The generic mechanism of MPO-mediated protein carbamylation has been elucidated recently and has been identified as a potentially crucial pathway that links smoking, inflammation and atherogenesis. HDL (high-density lipoprotein) exerts a physiologically beneficial effect of reducing arterial cholesterol deposition; however, there are considerable gaps in current understanding of the molecular basis of dysfunctional HDL formation. Especially deserving of attention is a contextual understanding of dysfunctional pro-atherogenic HDL formation in light of inflammatory changes in atheroma. The present review is especially timely in light of the solved structures of nascent and discoidal HDL and integrates the biochemical significance of MPO carbamylation in the context of these structures. Various avenues of experimental investigation are explored which will be crucial in understanding the vascular consequences of dysfunctional HDL formation and the identification of novel mechanistic pathways in vascular disease. It is anticipated that further knowledge on the intricacies of dysfunctional HDL formation, potentially by an MPO-driven pathway, will lead to considerable progress in identifying novel drug targets for atherosclerosis and characterization of the primary atherogenic process.

Liver transcriptome profiles associated with strain-specific Ehrlichia chaffeensis-induced hepatitis in SCID mice

Infection of humans with Ehrlichia chaffeensis, the etiologic agent of human monocytic ehrlichiosis, can cause hepatitis of various levels of severity. When the three human isolates of E. chaffeensis, each belonging to a different genogroup, are inoculated into severe combined immunodeficiency mice, the order of severity of clinical signs and bacterial burden detected in the liver is as follows (from greatest to least severity and highest to lowest burden): strain Wakulla, followed by strain Liberty, followed by strain Arkansas. In this article, we used microarray analysis to define transcriptional profiles characteristic of the histopathological features in the mouse liver. Cytokine and chemokine profiles and their receptor profiles were strikingly different among the three strains of E. chaffeensis: gamma interferon, CCL5, CXCL1, CXCL2, CXCL7, CXCL9, interleukin 2 receptor gamma (IL2Rgamma), IL21R, CCR2, and CXCR6 were highly upregulated with strain Arkansas; and tumor necrosis factor (TNF), CCL2, CCL3, CCL5, CCL6, CCL12, CCL20, CXCL2, CXCL7, CXCL9, CXCL13, TNF receptor superfamily 9 (TNFRSF9), TNFRSF13beta, IL1R2, IL2Rgamma, IL20Rbeta, IL21R, CCR1, CCR2, and CXCR4 were highly upregulated with strain Wakulla. With strain Liberty, only CXCL13 was highly upregulated, and IL13Ralpha2 was downregulated. In livers infected with the Arkansas strain, monocytes/macrophages and NK cells were enriched in the granulomas and an increase in NK cell marker mRNAs was detected. Livers infected with the Wakulla strain displayed infiltration of significantly more neutrophils and an increase in neutrophil marker mRNAs. Genes commonly upregulated in liver tissue infected with the three strains are other host innate immune and inflammatory response genes, including those encoding several acute-phase proteins. Genes downregulated commonly are related to host physiologic functions. The results suggest that marked modulation of host cytokine and chemokine profiles by E. chaffeensis strains underlies the distinct host liver disease.

NQO1, MPO, and the risk of lung cancer: a HuGE review

The aim of this study is to summarize the available molecular epidemiologic studies of lung cancer and metabolic genes, such as NAD(P)H quinone reductase 1 (NQO1) and myeloperoxidase (MPO). NQO1 plays a dual role in the detoxification and activation of procarcinogens whereas MPO has Phase I activity by converting lipophilic carcinogens into hydrophilic forms. Variant genotypes of both NQO1 Pro187 Ser and MPO G-463A polymorphisms may be related to low enzyme activity. The Pro/Ser and Ser/Ser genotypes combined of NQO1 was significantly associated with decreased risk of lung cancer in Japanese [random effects odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.56-0.88] among whom the variant allele is common. The variant genotype of MPO was associated with decreased risk of lung cancer among Caucasians (random effects OR = 0.70, 95% CI = 0.47-1.04). Gene-environment interactions in both polymorphisms may be hampered by inaccurate categorization of tobacco exposure. Evidence on gene-gene interactions is extremely limited. As lung cancer is a multifactorial disease, an improved understanding of such interactions may help identify individuals at risk for developing lung cancer. Such a study should include larger sample size and other polymorphisms in the metabolism of tobacco-derived carcinogens and address interactions with smoking status. The effects of polymorphisms are best represented by their haplotypes. In future studies on lung cancer, the development of haplotype-based approaches will facilitate the evaluation of haplotypic effects, either for selected polymorphisms physically close to each other or for multiple genes within the same drug-metabolism pathway.

Nasal complaints and signs of disease in farmers--a methodological study

CONCLUSION

The methods used in this study are suitable for field studies that involve examinations of groups of workers. For individual examinations, there is no gold standard method that can discriminate work-related discomfort from other causes of rhinitis.

OBJECTIVES

Studies of the effects of occupation on farmers' health have mainly focused on lower airways; few studies have examined effects on upper airways. This study investigated nasal functions in three groups of farmers (swine, milk and grain producers) and a control group using different methods, suitable for field studies.

SUBJECTS AND METHODS

Health-related complaints were examined and several functional tests, such as expirogram, olfactory threshold test, acoustic rhinometry, nasal lavage with biomarkers of inflammation (eosinophilic cationic proteins (ECP), myeloperoxidase (MPO), tryptase, albumin) and allergy tests were performed. The different tests were correlated to nasal complaints and to each other.

RESULTS

Nasal blockage complaints were more common among farmers; overall, nasal polyps were more frequent in grain producers. Objective parameters showed more pronounced mucosal swelling in farmers and higher concentrations of ECP in nasal lavage compared with controls. Lung function, olfactory threshold, atopy frequency and allergen-specific IgE to the storage mite Lepidoglyphus destructor did not differ between farmers and controls. Mucosal swelling measured with acoustic rhinometry was more pronounced in subjects with nasal complaints, hypersensitivity, nasal polyps and symptoms from lower airways. There was a correlation between biomarkers in nasal lavage (MPO, albumin and ECP).

Atopy, symptoms and indoor environmental perceptions, tear film stability, nasal patency and lavage biomarkers in university staff

OBJECTIVE

Study associations between airway symptoms, complaints on environmental perceptions, atopy definitions and biomarkers including tear film stability (BUT), nasal patency and nasal lavage (NAL). Personal predictors (gender, age, smoking, infections) for the biomarkers as well as associations between the biomarkers were also assessed.

METHODS

A cross-sectional study of 173 employees in four university buildings, response rate 86%. Tear film break up time (BUT) was measured by a non-invasive method (NIBUT) and self-reported (SBUT). NAL-analysis included eosinophilic cationic protein (ECP), myeloperoxidase (MPO), lysozyme and albumin. Total serum IgE, and specific IgE using Phadiatop was measured. Data on subjective symptoms, environmental perceptions and background data were collected by use of a questionnaire. Multiple regression analyses were applied.

RESULTS

Mean age was 43 years, 21% had weekly ocular, 21% nasal, and 17% laryngeal symptoms. Women had more complaints on environmental perceptions, shorter BUT and less nasal patency. Neither atopy (Phadiatop) nor Total IgE or allergy in the family, but asthma and hay fever was associated with mucosal symptoms or perceptions. Subjects with positive Phadiatop had higher levels of all NAL-biomarkers. Those with ocular symptoms had shorter BUT. Nasal symptoms were related to respiratory infections and laryngeal symptoms to NAL-lysozyme. Perceiving dry air was associated with lower BUT and reduced nasal volume difference before and after decongestion. Older subjects had greater nasal patency, and less atopy. All NAL-biomarkers were positively correlated. Higher lysozyme level was associated with less nasal patency and greater nasal decongestion.

CONCLUSIONS

BUT and NAL-lysozyme was associated with ocular, nasal, laryngeal symptoms and indoor environmental perceptions. Ever having had asthma and ever having had hay fever were predictors for symptoms and perceived air quality, respectively. Phadiatop, Total IgE, familiar allergy and ever eczema were not associated to symptoms or perceived environments. Age, gender and Phadiatop were main predictors for ocular and nasal biomarkers.

Pet keeping and dampness in the dwelling: associations with airway infections, symptoms, and physiological signs from the ocular and nasal mucosa

The aim was to utilize data from a study of occupational indoor environments to analyze symptoms and physiological signs in relation to the home environment. A medical investigation was performed at the workplace among university staff (n = 173) from four university buildings in Bergen, in March 2004. Tear film break up time (BUT) was measured by two methods. Nasal patency was measured by acoustic rhinometry. Nasal lavage fluid analysis (NAL) included eosinophilic cationic protein (ECP); myeloperoxidase (MPO), lysozyme and albumin. Atopy was assessed by total serum IgE and specific IgE (Phadiatop). Totally 21%, 21%, 18%, 11%, and 27% had weekly ocular, nasal, facial dermal symptoms, headache and tiredness, respectively, 15% had a damp dwelling, and 20% had a cat or dog. Multiple linear or logistic regressions were applied, controlling for age gender, smoking, and environmental factors. Building dampness was associated with increased NAL-lysozyme (P = 0.02) and an increase of airway infections [odd ratio (OR) = 3.14, P = 0.04]. Pet keeping was associated with difficulties to concentrate (OR = 5.10, P = 0.001), heavy headedness (OR = 4.35, P = 0.004), four more days with tiredness per month (P = 0.04), and less airway infections (OR = 0.32; P = 0.02). In conclusion, pet keeping was associated with more central nervous system (CNS)-symptoms but less airway infections. Dampness in the dwelling may have inflammatory effects on the airway mucosa, possibly mediated via increased infection proneness.

PRACTICAL IMPLICATIONS

The main health focus on pet keeping has been allergen exposure. Our study indicates that effects on airway infections and other types of symptoms should also be considered. The findings support the view that measures should be taken to reduce building dampness in dwellings.

Changes of symptoms, tear film stability and eosinophilic cationic protein in nasal lavage fluid after re-exposure to a damp office building with a history of flooding

The aim was to study health effects in office workers (N = 18) in a medical case book archive with dampness caused by flooding. They were first investigated in a building without dampness (exposure free for 10 days). Then all returned to the damp building, and were re-investigated after 2 days. We measured tear film break up time (BUT), nasal patency, biomarkers in nasal lavage (NAL), and dynamic spirometry. Both buildings had low CO(2) (380-600 ppm), low levels of respirable particles (8-10 microg/m(3)), and formaldehyde (5-7 microg/m(3)). The flooded building had slightly higher (149 ng/m(3) vs. 94 ng/m(3)) levels of microbial volatile organic compounds (MVOC). After 2 days of re-exposure, there was an increase of ocular (P < 0.001), nasal (P = 0.002), and throat symptoms (P < 0.001), dyspnea (P = 0.006), headache (P = 0.002), nausea (P = 0.04), and tiredness (P = 0.01). The median BUT decreased from 16 to 8 s (P = 0.003), and eosinophilic cationic protein (ECP) in NAL increased slightly (P = 0.04). A separate test of the weekday effect showed slight improvements, or no change of symptoms and signs from Monday to Wednesday. In conclusion, subjects previously exposed to building dampness had an increase of symptoms, reduced tear film stability, and signs of eosinophilic inflammation in the nasal mucosa after 2 days of re-exposure.

PRACTICAL IMPLICATIONS

The study is in agreement with previous cross-sectional studies, suggesting that building dampness may cause mucosal irritation, general symptoms such as headache and tiredness, impaired tear film stability, and eosinophilic inflammation in the airway mucosa. From a preventive point of view, health consequences of water leakage and flooding should not be neglected. The measurements of molds and microbial volatile organic compounds could not identify any obvious exposure contrast between the damp building and the dry control building. This illustrates the limitations of air measurements of microbial exposures in damp buildings.

IL-23-dependent IL-17 production is essential in neutrophil recruitment and activity in mouse lung defense against respiratory Mycoplasma pneumoniae infection

IL-23 induces IL-17 production in activated CD4+ T cells and participates in host defense against many encapsulated bacteria. However, whether the IL-23/IL-17 axis contributes to a Mycoplasma pneumoniae (Mp)-induced lung inflammation (e.g., neutrophils) has not been addressed. Using an acute respiratory Mp infection murine model, we found significantly up-regulated lung IL-23p19 mRNA in the early phase of infection (4h), and alveolar macrophages were an important cell source of Mp-induced IL-23. We further showed that Mp significantly increased IL-17 protein levels in bronchoalveolar lavage (BAL). Lung gene expression of IL-17, IL-17C and IL-17F was also markedly up-regulated by Mp in vivo. IL-17 and IL-17F were found to be derived mainly from lung CD4+ T cells, and were increased upon IL-23 stimulation in vitro. In vivo blocking of IL-23p19 alone or in combination with IL-23/IL-12p40 resulted in a significant reduction of Mp-induced IL-17 protein and IL-17/IL-17F mRNA expression, which was accompanied by a trend toward reduced lung neutrophil recruitment, BAL neutrophil activity, and Mp clearance. However, IL-23 neutralization had no effect on Mp-induced lung IL-17C mRNA expression. These results demonstrate that IL-17/IL-17F production is IL-23-dependent in an acute Mp infection, and contributes to neutrophil recruitment and activity in the lung defense against the infection.

Roles of the host oxidative immune response and bacterial antioxidant rubrerythrin during Porphyromonas gingivalis infection

The efficient clearance of microbes by neutrophils requires the concerted action of reactive oxygen species and microbicidal components within leukocyte secretory granules. Rubrerythrin (Rbr) is a nonheme iron protein that protects many air-sensitive bacteria against oxidative stress. Using oxidative burst-knockout (NADPH oxidase-null) mice and an rbr gene knockout bacterial strain, we investigated the interplay between the phagocytic oxidative burst of the host and the oxidative stress response of the anaerobic periodontal pathogen Porphyromonas gingivalis. Rbr ensured the proliferation of P. gingivalis in mice that possessed a fully functional oxidative burst response, but not in NADPH oxidase-null mice. Furthermore, the in vivo protection afforded by Rbr was not associated with the oxidative burst responses of isolated neutrophils in vitro. Although the phagocyte-derived oxidative burst response was largely ineffective against P. gingivalis infection, the corresponding oxidative response to the Rbr-positive microbe contributed to host-induced pathology via potent mobilization and systemic activation of neutrophils. It appeared that Rbr also provided protection against reactive nitrogen species, thereby ensuring the survival of P. gingivalis in the infected host. The presence of the rbr gene in P. gingivalis also led to greater oral bone loss upon infection. Collectively, these results indicate that the host oxidative burst paradoxically enhances the survival of P. gingivalis by exacerbating local and systemic inflammation, thereby contributing to the morbidity and mortality associated with infection.

Protection against lung damage in reduced-size liver transplantation

OBJECTIVE

This study examined the effect of ischemic preconditioning on pulmonary damage associated with reduced-size orthotopic liver transplantation (ROLT) and attempted to identify the underlying protective mechanisms.

DESIGN

Randomized and controlled animals study.

SETTING

Experimental laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Lung damage was evaluated in ROLT with or without preconditioning. Nitric oxide and interleukin (IL)-1 actions were altered pharmacologically.

MEASUREMENTS AND MAIN RESULTS

IL-1, tumor necrosis factor (TNF)-alpha, soluble TNF receptors (sTNFR), and inflammatory response in lung were measured after ROLT. Our results indicate the involvement of IL-1 in the lung damage following ROLT. Ischemic preconditioning, mediated by nitric oxide, reduced IL-1 release and protected against lung damage. Nitric oxide synthesis inhibition in the preconditioned group led to increased IL-1 levels and increased lung damage following ROLT, whereas the addition of IL-1 receptor antagonist protected against the injurious effects of nitric oxide inhibition. In addition, nitric oxide pretreatment gave similar results in terms of IL-1alpha and lung protection to those found in preconditioning. The benefits to the lung attributable to IL-1 inhibition might be linked to the effect of this cytokine on sTNFR, an endogenous mechanism that modulates systemic TNF actions. In fact, strategies aimed at inhibiting IL-1 action, including IL-1 receptor antagonist, ischemic preconditioning, and nitric oxide donor, increased systemic sTNFR2 and decreased free TNF, following ROLT. Similarly, nitric oxide synthesis inhibition in the preconditioned group, which increased IL-1alpha and lung damage, reduced systemic sTNFR2 and increased free TNF levels. These injurious effects were avoided when IL-1 action was inhibited.

CONCLUSIONS

Ischemic preconditioning and pharmacologic strategies that simulate its benefits protected against lung damage in an experimental model of ROLT. Our results also suggest a potential relationship between nitric oxide, IL-1, and TNF/sTNF in the benefits of preconditioning on the lung damage associated with ROLT.

Opposing effects of emphysema, hay fever, and select genetic variants on lung cancer risk

The authors compared histories of nonmalignant respiratory diseases (asthma, bronchitis, emphysema, hay fever, and pneumonia) in 1,553 lung cancer patients and 1,375 healthy controls enrolled in a Texas case-control study from 1995 to 2003. They incorporated data on two biologically relevant polymorphic genes, matrix metalloproteinase-1 and myeloperoxidase. Emphysema was associated with a statistically significant increased lung cancer risk (odds ratio (OR) = 2.87, 95% confidence interval (CI): 2.20, 3.76), while hay fever had a significant protective effect (OR = 0.58, 95% CI: 0.48, 0.70). Odds ratios were consistent after exclusion of respiratory disease diagnoses made up to 10 years before interview. There was little association between other respiratory diseases and lung cancer risk. Among carriers of "protective" genotypes, emphysema was associated with a 1.7-fold increased risk (95% CI: 0.84, 3.50), as compared with the substantially higher risk for persons possessing one (OR = 4.98, 95% CI: 2.94, 8.44) or two (OR = 4.23, 95% CI: 1.84, 9.73) "adverse" genotypes. For hay fever, significantly decreased risks were evident with one (OR = 0.32, 95% CI: 0.21, 0.50) or two (OR = 0.35, 95% CI: 0.19, 0.66) protective genotypes as compared with none (OR = 0.69, 95% CI: 0.30, 1.59). The biologic role of respiratory disease in lung cancer is unclear. Further study may yield new insights for identification of susceptible subgroups.

In vivo suppressive effect of nuclear factor-κB inhibitor on neutrophilic inflammation of grafts after orthotopic liver transplantation in rats

AIM: To investigate the effect of pyrrolidine dithiocarbamate (PDTC), a novel nuclear factor-κB (NF-κB) inhibitor, on expression of multiple inflammatory mediators and neutrophilic inflammation of cold preserved grafts after rat liver transplantation and its significance.

METHODS: Orthotopic liver transplantation (OLT) was performed after 24 h of cold storage using University of Wisconsin solution with varied concentrations of PDTC. We determined the time course of NF-κB activation and expression of multiple inflammatory signals, such as tumor necrosis factor-α (TNF-α), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM-1) by ELISA methods. Serum alanine aminotransferase (ALT), intrahepatic myeloperoxidase (MPO)/WBC (a measure of neutrophil accumulation) and Mac-1 expression (a measure of circulating neutrophil activity) were also evaluated.

RESULTS: PDTC decreased NF-κB activation induced by prolonged cold preservation in a dose dependent manner (from 20 mmol/L to 60 mmol/L), diminished TNF-α, CINC, ICAM-1 proteins in the grafts, and reduced the expression of increases in plasma TNF-α levels induced by prolonged cold preservation. Neutrophilic inflammation of the graft was significantly suppressed after preservation with PDTC (P < 0.05). The total neutrophil accumulation in PDTC (40 mmol/L) group (7.04 ± 0.97) was markedly reduced compared to control group (14.07 ± 1.31) (P < 0.05). Mac-1 expression was significantly reduced in PDTC (40 mmol/L) group (181 ± 11.3%) compared with the control group (281 ± 13.2%) (P < 0.05) at 6 h after reperfusion. Furthermore, PDTC inhibited the increased serum ALT levels after liver transplantation.

CONCLUSION: PDTC can inhibit B NF-κB activation and expression of the inflammatory mediators, which are associated with improved graft viability via inhibiting intrahepatic neutrophilic inflammation. Our study suggests that a therapeutic strategy directed at inhibition of NF-κB activation in the transplanted liver might be effective in reducing intrahepatic neutrophilic inflammation, and would be beneficial to cold preserved grafts.

Is ischemic preconditioning a useful strategy in steatotic liver transplantation?

This study examined the effect of preconditioning on steatotic livers for transplantation and attempted to identify the underlying protective mechanisms. Blood flow alterations, neutrophil accumulation, tumor necrosis factor alpha release and lipid peroxidation were observed in nonsteatotic livers after transplantation. Steatotic and nonsteatotic liver grafts were similar in their blood flow, neutrophil accumulation, and TNF release after transplantation. However, in the presence of steatosis, lipid peroxidation and hepatic injury increased. In addition, recipients of steatotic liver grafts were more vulnerable to lung damage associated with transplantation. The conversion of xanthine dehydrogenase to xanthine oxidase and the accumulation of xanthine during cold ischemia was greater in steatotic than in nonsteatotic liver grafts. The results obtained with xanthine oxidase inhibitors indicated that xanthine/xanthine oxidase could be responsible for the increased lipid peroxidation as well as the exacerbated liver and lung damage associated with transplantation of steatotic livers. Preconditioning reduced the xanthine accumulation and percentage of xanthine oxidase seen in steatotic liver grafts during cold ischemia, and conferred protection against liver and lung damage following transplantation. The benefits of preconditioning could be mediated by nitric oxide. These findings suggest that preconditioning could be a relevant new strategy to protect against the inherent risk of steatotic liver failure following transplantation.

Myeloperoxidase (MPO) −463G→A Reduces MPO Activity and DNA Adduct Levels in Bronchoalveolar Lavages of Smokers

The myeloperoxidase (MPO) −463G→A genetic polymorphism is associated with a reduced risk for lung cancer, but the underlying mechanism is not yet elucidated. Therefore, the impact of this polymorphism on MPO activity and lipophilic DNA adducts was studied in respectively bronchoalveolar lavage (BAL) fluid and cells, from 106 smoking Caucasian lung patients. MPO activity was determined spectrophotometrically, aromatic DNA adducts by 32P-postlabeling and MPO genotypes by RFLP analysis. Frequencies of MPO −463AA (13%), MPO −463AG (36%), and MPO −463GG (51%) were in line with earlier observations. MPO activity/neutrophil was lower in MPO −463AA (median 0.04 pU/cell) than in MPO −463AG (median 0.07 pU/cell) and MPO −463GG (median 0.14 pU/cell; P = 0.059) individuals. DNA adducts in BAL cells were measured in 11 MPO −463AA subjects and equal numbers of MPO −463AG and MPO −463GG subjects matched for smoking, age, gender, and clinical diagnosis. DNA adduct levels in MPO −463AA individuals (median 0.62 adducts/108 nucleotides) were lower than in MPO −463AG (median 1.51 adducts/108 nucleotides) and MPO −463GG (median 3.26 adducts/108 nucleotides; P = 0.003) subjects. Overall, no significant correlation was observed between amount of inhaled tar/day and DNA adduct levels. However, correlations improved considerably on grouping according to the MPO genotype; MPO −463AA subjects were the least responsive (R2 = 0.73, slope = 0.4, P = 0.01) followed by MPO −463AG subjects (R2 = 0.70, slope = 1.3, P = 0.01) and MPO −463GG patients (R2 = 0.67, slope = 2.8, P = 0.02). These data demonstrate that MPO −463AA/AG genotypes are associated with (a) reduced MPO activity in BAL fluid and (b) reduced smoking-related DNA adduct levels in BAL cells in a gene-dose manner. These data provide a plausible biological explanation for the reduced risk for lung cancer as observed in MPO −463AA/AG compared with MPO −463GG subjects.

Effect of cold-ischemia time on nuclear factor-κB activation and inflammatory response in graft after orthotopic liver transplantation in rats

AIM: To study the mechanism and effect of nuclear factor-κB (NF-κB) activation and inflammatory response on the extended cold-preserved graft injury after orthotopic liver transplantation (OLT).

METHODS: OLT was performed in rats with varying time of cold ischemia grafts (6, 18 and 24 h in University Wisconsin solution at 4 °C). We determined the time of NF-κB activation and expression of tumor necrosis factor-α(TNF-α), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM-1) within 6 h after reperfusion. Serum alarming aminotransferase (ALT), neutrophil sequestration, circulating neutrophil CD11b and L- selectin expression were also evaluated.

RESULTS: The accumulation of neutrophils in the graft was significantly increased in the 18 h and 24 h cold-ischemia groups within 0.5 h after reperfusion, compared with the 6 h group. But the strongly activated neutrophils was slightly increased at 2 h after reperfusion and remained at high levels 4 h after reperfusion, which was synchronized with the common situation of recipients after transplantation. Prolonged cold-preservation did not affect neutrophil accumulation and activation. NF-κB activation preceded the expression of TNF-α, CINC, and ICAM-1 in the liver, which was significantly increased with prolonged cold preservation. In prolonged cold preserved grafts, prominently elevated NF-κB activation occurred at 0.5 h and 1 h, compared with that at 2 h after reperfusion, which was consistent with greatly increased intrahepatic TNF-α response.

CONCLUSION: NF-κB activation is correlated with the expression of TNF-α, CINC, and ICAM-1 in vivo in OLT rats. Extended cold preservation of grafts might up-regulate TNF-α, CINC, and ICAM-1 expression in the grafts, most probably through elevated NF-κB activation, and might contribute to neutrophil infiltration in the grafts after reperfusion. Elevated NF-κB activity is harmful to inflammatory response in the grafts, and inhibited NF-κB activity might protect against early graft injury after liver transplantation.

Combined effect of MPO, GSTM1 and GSTT1 polymorphisms on chromosome aberrations and lung cancer risk

The role of myeloperoxidase (MPO), and glutathione S-transferase mu and theta (GSTM1 and GSTT1) genetic polymorphisms on lung cancer risk was investigated in 110 Caucasian patients and 119 matched controls. Single genotype variants were not significantly associated with lung cancer risk. However, inheritance of the combined GSTM1 and GSTT1 null genotypes showed a significant increase in risk (crude OR = 2.32, 95% CI = 1.01-6.04). Based on adjustment by age, gender and smoking history, the MPO GA interacted with the presence of GSTM1 and GSTT1 genotypes to significantly reduce the risk (OR = 0.17, 95% CI = 0.03-0.98). From the chromosome aberration (CA) study in a subgroup of 79 patients and 69 matched controls, patients had significantly more CA than the controls. Among the patients, GSTM1 null was associated with a significant increase of CA and MPO AA was associated with a significant decrease of CA compared to their respective wild-type genotypes. After stratifying by smoking history (< or = and > 40 pack-years) and genotype, patients still had significantly more CA than the respective controls in most genotype categories. This indicates that the patients had additional contributing factors such as other susceptibility genes and/or different styles of smoking compared with the controls. In conclusion, our study indicates that CA is a useful biomarker to show the functional characteristics of genotypes and the interactive effects from combined genotypes. Therefore, our study strengthens the combined use of genotype and biomarkers for genetic susceptibility to environmental cancer.

Relationship between myeloperoxidase promotor polymorphism and disease severity in sarcoidosis

BACKGROUND

Previously, we demonstrated that the number of polymorphonuclear neutrophils (PMNs) in bronchoalveolar lavage fluid (BALF) is useful in distinguishing sarcoidosis patients with a favorable outcome from those having a more severe course of disease. Neutrophils contain the oxidant-generating enzyme myeloperoxidase (MPO). Cellular levels of MPO can be influenced by functional promotor polymorphisms, ?463G/A and ?129G/A, which may modify disease severity.

METHODS

In the present study, we investigated two MPO promotor polymorphisms in 110 sarcoidosis patients and in 191 ethnically matched controls. Pulmonary disease severity was evaluated by means of radiographic staging, HRCT scoring, lung function, and exercise capacity testing.

RESULTS

No significant differences were found between sarcoidosis patients and healthy controls with regard to either polymorphism. Nor was any association observed between ?463 G/A and ?129 G/A polymorphism and the severity of sarcoidosis.

CONCLUSIONS

The functional MPO promotor polymorphisms ?463G/A and ?129G/A did not explain disease severity in the sarcoidosis population studied. Future studies are needed to identify predictive features useful in guiding therapeutic strategies and to determine difficult-to-treat cases.

The effect of recombinant interleukin-8 on eosinophils' and neutrophils' migration in vivo and in vitro

BACKGROUND

Interleukin-8 (IL-8) is a chemokine that causes chemotaxis of neutrophils, eosinophils and lymphocytes in vitro; however, its role as a chemoattractant in allergic inflammation is unclear. The objective of this study was to investigate the effect of nasal instillation of IL-8 on the influx of inflammatory cells.

METHODS

Twelve patients suffering from seasonal allergic rhinitis hypersensitive to grass pollens, with average age 30.1 +/- 2.67 years were challenged both with diluent for IL-8 and IL-8 on a subsequent day, in two phases: before the pollen season (unprimed mucosa) and during the season (primed mucosa). The number of neutrophils, eosinophils and myeloperoxydase (MPO) levels in the nasal fluid collected after IL-8 or placebo challenge were determined.

RESULTS

Challenge with IL-8 of primed nasal mucosa induced a significant influx of neutrophils (29 x 10(4) cells/ml at 0.5 h, 251 x 10(4) at 2 h and 334 x 10(4) at 3 h). Number of eosinophils in comparison with diluent challenge was not significant. There was no difference in MPO levels in the nasal lavage between IL-8 and diluent challenge of unprimed and primed mucosa. We did not find the relationship between MPO levels and the neutrophils number in the lavage (rank Spearman factor, RS = 0.258, P = 0.42).

CONCLUSION

We have demonstrated that IL-8 causes influx of neutrophils but not eosinophils into nasal mucosa in vivo. MPO level seems to be of little value as a marker of neutrophil influx into nasal mucosa.

Genetic polymorphism in myeloperoxidase but not GSTM1 is associated with risk of lung squamous cell carcinoma in a Chinese population

Myeloperoxidase (MPO), an enzyme derived from neutrophils, metabolically activates a wide range of carcinogens, whereas glutathione S-transferase M1 (GSTM1) detoxifies various electrophilic metabolites. A -463G-->A polymorphism in the promoter region of the MPO gene diminishes the expression of MPO and has been consistently shown to be associated with reduced risk of lung cancer in different ethnic populations. In our study, we have assessed the role of this polymorphism in lung cancer risk in a Chinese population. Genotypes of MPO and GSTM1 were determined by PCR-SSCP and multiplex PCR in 314 patients with lung cancer and 320 frequency-matched controls. The allele frequency for MPO -463A was found to be 0.155 in controls and 0.114 in cases. Subjects with the MPO -463GG genotype were at an increased risk of squamous cell carcinoma (SCC) of the lung compared to those having at least one -463A variant allele (adjusted odds ratio [OR] 2.35; 95% confidence interval [CI] 1.40-3.94). Stratified analysis suggested an interaction between heavy smoking (> or =26 pack-years) and the MPO-463GG genotype. The adjusted OR of lung SCC for those having MPO-463GG genotype and smoked > or =26 pack-years was 20.50 (95% CI 5.58-75.33) compared to 6.22 (95% CI 1.72-22.47) for those smoked > or =26 pack-years but having at least one variant A allele (p = 0.023, test for homogeneity). This effect of the MPO polymorphism was not observed in lung adenocarcinoma. GSTM1 deletion was quite common in both controls (49.4%) and cases (50.3%) but was not associated with risk of lung cancer alone or in combination with the MPO polymorphism. Our results confirm the previous reports showing that the variant A allele of MPO has a protective effect against risk of lung cancer.

Are women more sensitive than men to 2-propanol and m-xylene vapours?

AIMS

To evaluate possible differences between men and women in acute health effects after controlled short term chamber exposure to vapours of two common organic solvents.

METHODS

Fifty six healthy volunteers (28 per sex) were exposed to 150 ppm 2-propanol, 50 ppm m-xylene, and clean air for two hours at rest. The subjects rated symptoms on a visual analogue scale before, during, and after the exposure. Blinking frequency was measured continuously during exposure. Pulmonary function, nasal swelling, inflammatory markers (lysozyme, eosinophilic cationic protein, myeloperoxidase, albumin) in nasal lavage and colour vision (Lanthony D-15 desaturated panel) were measured before and at 0 and 3 hours after the exposure.

RESULTS

There were no significant sex differences in response to solvent exposure with respect to blinking frequency, lung diffusing capacity, nasal area and volume, inflammatory markers in nasal lavage, and colour vision. Increased symptoms were rated by both sexes for nearly all 10 questions during exposure to 2-propanol or m-xylene, most increases being significant at one time point at least. The rating of "discomfort in the throat or airways" increased more in women during exposure to 2-propanol or m-xylene. During exposure to 2-propanol the rating of "fatigue" was more increased in men after one hour, but more increased in women after two hours of exposure. With regard to pulmonary function, women had small but significant decreases in FVC, FEV(1)/FVC, and FEF(75) three hours after exposure to m-xylene, but only the decrease in FVC was significantly different from that in men.

CONCLUSION

Our results suggest that women are slightly more sensitive than men to the acute irritative effects of 2-propanol and m-xylene vapours.

Preconditioning protects liver and lung damage in rat liver transplantation: role of xanthine/xanthine oxidase

This study was designed to evaluate whether ischemic preconditioning could confer protection against liver and lung damage associated with liver transplantation. The effect of preconditioning on the xanthine/xanthine oxidase (XOD) system in liver grafts subjected to 8 and 16 hours of cold ischemia was also evaluated. Increased xanthine levels and marked conversion of xanthine dehydrogenase (XDH) to XOD were observed after hepatic cold ischemia. Xanthine/XOD could play a role in the liver and lung damage associated with liver transplantation. This assumption is based on the observation that inhibition of XOD reduced postischemic reactive oxygen species (ROS) generation and hepatic injury as well as ensuing lung inflammatory damage, including neutrophil accumulation, oxidative stress, and edema formation. Ischemic preconditioning reduced xanthine accumulation and conversion of XDH to XOD in liver grafts during cold ischemia. This could diminish liver and lung damage following liver transplantation. In the liver, preconditioning prevented postischemic ROS generation and hepatic injury as well as the injurious effects in the lung following liver transplantation. Administration of xanthine and XOD to preconditioned rats led to hepatic ROS and transaminase levels similar to those found after reperfusion and abolished the protective effect of preconditioning on the lung inflammatory damage. In conclusion, ischemic preconditioning reduces both liver and lung damage following liver transplantation. This endogenous protective mechanism is capable of blocking xanthine/XOD generation in liver grafts during cold ischemia.

Genetic polymorphisms and lung cancer susceptibility: a review

Lung cancer is a major cause of cancer-related death in the developed countries and the overall survival rate has still an extremely poor. Cigarette smoking is an established risk factor for lung cancer although a possible role for genetic susceptibility in the development of lung cancer has been inferred from familial clustering of the disease and segregation analyzes. Everyone may have a unique combination of polymorphic traits that modify genetic susceptibility and response to drugs, chemicals and carcinogens. Developments in molecular biology have led to growing interest in investigation of biological markers, which may increase predisposition to lung carcinogenesis. Therefore, the high-risk genotype of an individual could be determined easily. As there are the great number of carcinogen-activating and -detoxifying enzymes, the variation in their expression and the complexity of exposures to tobacco carcinogens, the existence of multiple alleles at loci of those enzymes may result in differential susceptibilities of individuals. This review summarize data addressing the relationships of lung cancer to markers of genetic susceptibility genes, including metabolic polymorphisms other than well-investigated cytochrome P450s or glutathione S-transferases, DNA repair genes and the p53 tumor suppressor gene. Among genetic polymorphisms reviewed here, myeloperoxidase gene (a G to A mutation) and microsomal epoxide hydrolase exon 4 polymorphism (substitution of Arg for His) were significantly associated with lung cancer risk. As lung cancer is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci may help identify individuals who are at increased risk for lung cancer. Hopefully, in the future we will be able to screen for lung cancer susceptibility by using specific biomarkers.

Ischemic preconditioning increases the tolerance of Fatty liver to hepatic ischemia-reperfusion injury in the rat

Hepatic steatosis is a major risk factor in ischemia-reperfusion. The present study evaluates whether preconditioning, demonstrated to be effective in normal livers, could also confer protection in the presence of steatosis and investigates the potential underlying protective mechanisms. Fatty rats had increased hepatic injury and decreased survival after 60 minutes of ischemia compared with lean rats. Fatty livers showed a degree of neutrophil accumulation and microcirculatory alterations similar to that of normal livers. However, in presence of steatosis, an increased lipid peroxidation that could be reduced with glutathione-ester pretreatment was observed after hepatic reperfusion. Ischemic preconditioning reduced hepatic injury and increased animal survival. Both in normal and fatty livers, this endogenous protective mechanism was found to control lipid peroxidation, hepatic microcirculation failure, and neutrophil accumulation, reducing the subsequent hepatic injury. These beneficial effects could be mediated by nitric oxide, because the inhibition of nitric oxide synthesis and nitric oxide donor pretreatment abolished and simulated, respectively, the benefits of preconditioning. Thus, ischemic preconditioning could be an effective surgical strategy to reduce the hepatic ischemia-reperfusion injury in normal and fatty livers under normothermic conditions, including hepatic resections, and liver transplantation.

Association between asbestos exposure, cigarette smoking, myeloperoxidase (MPO) genotypes, and lung cancer risk

BACKGROUND

As observed in tobacco-associated carcinogenesis, genetic factors such as the polymorphic metabolic/oxidative enzyme myeloperoxidase (MPO) could modulate individual susceptibility to asbestos-associated carcinogenesis.

METHODS

RFLP-PCR analysis identified the MPO genotypes in 375 Caucasian lung cancer cases and 378 matched controls. An epidemiological interview elicited detailed information regarding smoking history and occupational history and exposures.

RESULTS

Asbestos exposure was associated with a significantly elevated risk estimate (OR = 1.45; 95% CI 1.04-2.02). On stratified analysis, we found the MPO genotypes modified the effect of asbestos exposure on lung cancer risk. Specifically, G/G carriers who were exposed to asbestos had an odds ratio (OR) of 1.72 (95% CI; 1.09-2.66), while A-allele carriers (G/A + A/A) exposed to asbestos exhibited a reduced OR of 0.89 (95% CI; 0.56-1.44). The OR was further reduced to 0.73 (0.49-1.06) for A-allele carriers not exposed to asbestos. A similar trend was observed for the joint effects between the MPO genotypes and pack-years smoking. Next, all three risk factors (MPO genotypes, asbestos exposure, and smoking) were analyzed simultaneously for joint effects. Heavy smokers with the G/G genotype and a history of asbestos exposure demonstrated a statistically significant elevated risk estimate (OR = 2.19; 95% CI 1.16-4.11), while the A-allele carriers with the same exposure profile were at a lower risk for lung cancer (OR = 1.18; 95% CI 0.58-2.38). The A-allele genotypes demonstrated similar protective effects for the other three exposure profiles.

CONCLUSIONS

For a similar level of exposure to established carcinogens, individuals with the MPO A-allele genotypes appear to have a reduced risk of lung cancer.

Generation of reactive oxygen metabolites by the varicose vein wall

OBJECTIVES

to evaluate the content of lipid peroxidation products (expressed by the concentration of thiobarbituric acid-reactive substances; TBARS), the content of myeloperoxidase (MPO), and the localisation of xanthine oxidase (XO) in varicose veins (vv), varicose veins with superficial thrombophlebitis and unchanged saphenous veins.

METHODS

varicose saphenous veins, varicose veins with superficial thrombophlebitis and normal saphenous veins obtained during varicose vein surgery on 36 patients as well as healthy saphenous veins from cadaver organ donors (control). Homogenates were prepared in which TBARS concentration and MPO content were determined. Immunohistochemical staining to detect XO was also performed.

RESULTS

the highest concentration of TBARS occurred in vv with superficial thrombophlebitis, the lowest in donor vein. The highest content of MPO was observed in vv and slightly lower - in varicose veins with thrombophlebitis. A positive reaction for XO was seen in vv wall endothelium. Specimens of vv with thrombophlebitis revealed strong, intense staining in endothelium as well as in vasa vasorum.

CONCLUSIONS

varicose veins, especially those complicated with superficial thrombophlebitis revealed increased free radical generation. Its sources might be neutrophils, and in vv complicated with superficial thrombophlebitis-xanthine oxidase.

The combination of ischemic preconditioning and liver Bcl-2 overexpression is a suitable strategy to prevent liver and lung damage after hepatic ischemia-reperfusion

The present study evaluates the effectiveness of ischemic preconditioning and Bcl-2 overexpression against the liver and lung damage that follow hepatic ischemia-reperfusion and investigates the underlying protective mechanisms. Preconditioning and Bcl-2, respectively, reduced the increased tumor necrosis factor (TNF) and macrophage inflammatory protein-2 (MIP)-2 levels observed after hepatic reperfusion. Bcl-2 overexpression or anti-MIP-2 pretreatment seems to be more effective than preconditioning or anti-TNF pretreatment against inflammatory response, microcirculatory disorders, and subsequent hepatic ischemia-reperfusion injury. Furthermore, each one of these strategies individually was unable to completely inhibit hepatic injury. The combination of preconditioning and Bcl-2 overexpression as well as the combined anti-TNF and anti-MIP-2 pretreatment totally prevented hepatic injury, whereas the benefits of preconditioning and Bcl-2 were abolished by TNF and MIP-2. In contrast to preconditioning, Bcl-2 did not modify lung damage induced by hepatic reperfusion. This could be explained by the differential effect of both treatments on TNF release. Anti-TNF therapy or preconditioning, by reducing TNF release, reduced pulmonary inflammatory response, whereas the benefits of preconditioning on lung damage were abolished by TNF. Thus, the induction of both Bcl-2 overexpression in liver and preconditioning, as well as pharmacological strategies that simulated their benefits, such as anti-TNF and anti-MIP-2 therapies, could be new strategies aimed to reduce lung damage and inhibit the hepatic injury associated with hepatic ischemia-reperfusion.