Mária Szilasi

Mitogen-Activated Protein Kinases Regulate Susceptibility to Ventilator-Induced Lung Injury

Background Mechanical ventilation causes ventilator-induced lung injury in animals and humans. Mitogen-activated protein kinases have been implicated in ventilator-induced lung injury though their functional significance remains incomplete. We characterize the role of p38 mitogen-activated protein kinase/mitogen activated protein kinase kinase-3 and c-Jun-NH2-terminal kinase-1 in ventilator-induced lung injury and investigate novel independent mechanisms contributing to lung injury during mechanical ventilation. Methodology and Principle Findings C57/BL6 wild-type mice and mice genetically deleted for mitogen-activated protein kinase kinase-3 (mkk-3 −/−) or c-Jun-NH2-terminal kinase-1 (jnk1 −/−) were ventilated, and lung injury parameters were assessed. We demonstrate that mkk3 −/− or jnk1 −/− mice displayed significantly reduced inflammatory lung injury and apoptosis relative to wild-type mice. Since jnk1−/− mice were highly resistant to ventilator-induced lung injury, we performed comprehensive gene expression profiling of ventilated wild-type or jnk1−/− mice to identify novel candidate genes which may play critical roles in the pathogenesis of ventilator-induced lung injury. Microarray analysis revealed many novel genes differentially expressed by ventilation including matrix metalloproteinase-8 (MMP8) and GADD45α. Functional characterization of MMP8 revealed that mmp8−/− mice were sensitized to ventilator-induced lung injury with increased lung vascular permeability. Conclusions We demonstrate that mitogen-activated protein kinase pathways mediate inflammatory lung injury during ventilator-induced lung injury. C-Jun-NH2-terminal kinase was also involved in alveolo-capillary leakage and edema formation, whereas MMP8 inhibited alveolo-capillary protein leakage.

Pathology of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease is one of the leading causes of death and morbidity worldwide. Despite intensive investigation, its pathology and pathophysiology are not well understood. The hallmarks of the disease are irreversible airflow limitation and chronic inflammation. Small airway obstruction due to progressive inflammation and fibrosis, and the loss of elastic recoil mediated by elastolysis and apoptosis equally contribute to pathologic changes. However, it is debated to what extent the obstruction of large airways leads to altered lung function. Three morphologic entities are described in the literature under one disease; chronic bronchitis, obstructive bronchiolitis and emphysema may appear in the same patient at the same time. The authors review pathologic changes observed in chronic obstructive pulmonary disease, including acute exacerbations and secondary pulmonary hypertension as severe but common complications of the disease. Furthermore, we detail recent scientific evidences for major cellular and molecular inflammatory pathway activation. These mechanisms result in accelerated apoptosis, remodeling and increased proinflammatory cytokine release. Targeting intracellular pathological changes may lead to the discovery of a new generation of drugs that could reduce chronic obstruction before airway irreversibility is established.

Serum human epididymis protein 4 (HE4) as a tumor marker in men with lung cancer

Abstract Background: Human epididymis protein 4 (HE4) is a reliable tumor marker for ovarian cancer, but only limited data are available on HE4 levels in lung malignancies. Methods: HE4 levels were measured at diagnosis in 98 men with lung cancer at different stages of the disease, and these results were compared to an age-matched healthy male cohort (n=98). The concentrations of classical tumor markers were also determined, and their efficacy was compared to that of HE4. Results: Compared to healthy controls, patients with lung neoplasm showed significantly higher HE4 levels [118.2 (80.6–150.1) pmol/L vs. 62.2 (47.2–76.1) pmol/L; p<0.001]. Although age and smoking modulated HE4 levels in the healthy cohort, no such effect was observed in the patient population. The area under the receiver operating characteristic curve (ROC-AUC) for HE4 was 0.848 (95% CI 0.792–0.904) for differentiating lung cancer patients from healthy controls, with a cut-off value of 97.6 pmol/L (sensitivity: 64.3%, specificity: 95.9%). HE4 levels were significantly elevated in all stages of lung cancer, and even in patients without clinical symptoms (p<0.05), but no difference was found between the different histological subgroups. A significant correlation was found between HE4 values and the tumor size determined by CT/MRI (Spearman’s ρ=0.227, p=0.030). The combination of HE4 with CEA and CA 125 considerably enhanced the diagnostic efficacy [ROC-AUC: 0.963 (95% CI 0.937–0.990), sensitivity: 91.8%, specificity: 92.8%]. Conclusions: Our data suggest that serum HE4, especially in combination with CEA and CA 125, qualifies as a surrogate diagnostic marker in men with lung cancer.

Enzyme-based intravascular defense against organophosphorus neurotoxins: Synergism of dendritic-enzyme complexes with 2-PAM and atropine

Novel, enzyme-complexed, nano-delivery systems have been developed to antagonize the lethal effects of organophosphorus (OP) molecules such as diisopropylfluorophosphate and paraoxon. Polymeric nanocapsules can be used to deliver metabolizing enzymes to the circulation, often increasing the enzymes efficacy by extending their circulatory life and, in some cases, enhancing their specific activity. The bacterial enzymes organophosphorus hydrolase (OPH) and organophosphorus anhydrolase (OPAA) were encapsulated within a nanocapsule, polyoxazoline-based dendritic polymer carrier and employed in combination with the OP antagonists pralidoxime (2-PAM) and atropine. The effective doses for OPH and OPAA, respectively, were 500–550 and 1500–1650 units/kg mice; the size of the entire complex is approximately 200 nm in diameter. These studies compare the efficacy of the two enzymes as prophylactic systems encapsulated within the dendritic polymer. When used in combination with 2-PAM and atropine, the dendritic encapsuled OPAA provided a 25×LD50 protection against DFP intoxication, while the similarly constructed OPH complex showed a more dramatic protection (780×LD50) against paraoxon intoxication in Balb/c mice. The studies demonstrate a synergistic enhancement of the antagonist, since the antidotal protection of 2-PAM+atropine against DFP and paraoxon is approximately 8 and 60×LD50, respectively.

Characterization of liposomal vesicles encapsulating rhodanese for cyanide antagonism.

The major mechanism of removing cyanide from the body is its enzymatic conversion by a sulfurtransferase, e.g. rhodanese, to the less toxic thiocyanate in the presence of a sulfur donor. Earlier results demonstrated that externally administered encapsulated rhodanese significantly enhances the in vivo efficacy of the given sulfur donor. Present studies are focused on liposomal carrier systems encapsulating rhodanese. Physicochemical properties, e.g. membrane rigidity, size distribution, surface potential, osmolarity, and viscosity, were determined for various liposomal lipid compositions and hydrating buffers to establish in vitro stability and in vivo fate. Lipid composition was also optimized to achieve maximum encapsulation efficiency.

Nanoencapsulated and microencapsulated enzymes in drug antidotal therapy.

A catalytic bioscavenger for the therapeutic and prophylactic defense against recognized chemical threat agents has been a long-standing objective of civilian and military research. Among the toxic agents, organophosphate molecules and cyanide have been widely studied. In order to overcome the limitations of traditional antidotal therapies, isolated, purified, recombinant enzymes with bacterial origin possessing fast catalytic activity were used in in vitro and in vivo experiments. However, the fast degradation, excretion and adverse immunologic reaction against enzymes limit their in vivo use. Development of biodegradable, nontoxic carrier systems, microparticles, and nanoparticles—offering advantageous pharmacokinetic parameters was suggested. Present work deals with the perspectives of carrier systems, such as resealed and annealed erythrocytes and sterically stabilized liposomes. Dendritic polymers and polymer-conjugated enzymes, being in the focus of extensive research efforts nowadays, are also discussed.

Concerning the importance of changes in hemorheological parameters caused by acid-base and blood gas alterations in experimental surgical models

Acid-base equilibrium and pH of blood have important clinical consequences in numerous diseases and pathophysiological conditions. The micro-rheological parameters of blood, such as red blood cell deformability and red blood cell aggregation are influenced by several metabolic factors, and provide information regarding inflammatory, septic and tissue or organ ischemia-reperfusion processes. Despite the anticipated logical relation of the blood acid-base condition, blood gas parameters and pH to red blood cell deformability and aggregation, controversial data can be found in the literature. Furthermore, related to ischemia-reperfusion hemorheological studies little is known about this issue. In this paper we aimed to thought-provokingly overview some aspect of acid-base changes, blood pH and hemorheological parameters, discussing certain results from ischemia-reperfusion experimental surgical models (local versus systemic changes), laboratory technical and experimental design protocols related to in vitro and in vivo studies.

Exposure to inhomogeneous static magnetic field beneficially affects allergic inflammation in a murine model

Previous observations suggest that static magnetic field (SMF)-exposure acts on living organisms partly through reactive oxygen species (ROS) reactions. In this study, we aimed to define the impact of SMF-exposure on ragweed pollen extract (RWPE)-induced allergic inflammation closely associated with oxidative stress. Inhomogeneous SMF was generated with an apparatus validated previously providing a peak-to-peak magnetic induction of the dominant SMF component 389 mT by 39 T m−1 lateral gradient in the in vivo and in vitro experiments, and 192 mT by 19 T m−1 in the human study at the 3 mm target distance. Effects of SMF-exposure were studied in a murine model of allergic inflammation and also in human provoked skin allergy. We found that even a single 30-min exposure of mice to SMF immediately following intranasal RWPE challenge significantly lowered the increase in the total antioxidant capacity of the airways and decreased allergic inflammation. Repeated (on 3 consecutive days) or prolonged (60 min) exposure to SMF after RWPE challenge decreased the severity of allergic responses more efficiently than a single 30-min treatment. SMF-exposure did not alter ROS production by RWPE under cell-free conditions, while diminished RWPE-induced increase in the ROS levels in A549 epithelial cells. Results of the human skin prick tests indicated that SMF-exposure had no significant direct effect on provoked mast cell degranulation. The observed beneficial effects of SMF are likely owing to the mobilization of cellular ROS-eliminating mechanisms rather than direct modulation of ROS production by pollen NAD(P)H oxidases.

Association of pre-eclampsia with or without superimposed chronic hypertension in pregnant women with the risk of congenital abnormalities in their offspring: a population-based case-control study

OBJECTIVE To investigate the association of pre-eclampsia (PE) or PE with superimposed chronic hypertension (PE+SCH) in pregnant women with the risk of various structural birth defects (i.e. congenital abnormalities) in their offspring. STUDY DESIGN A population-based case-control study using the Hungarian Case-Control Surveillance of Congenital Abnormalities data set (1980-1996), including 22,843 cases with congenital abnormalities and 38,151 matched controls without any congenital abnormalities. The incidence of PE and PE+SCH was compared in women who had offspring with congenital abnormalities (cases) and women who had offspring without any congenital abnormalities (controls). RESULTS The incidence of PE was examined in 585 cases and 1017 controls, and the incidence of PE+SCH was examined in 154 cases and 269 controls. None of the 25 studied types of congenital abnormality was found to be more likely among the offspring of women with PE. However, the risks of renal dysgenesis [odds ratio (OR) 4.7, 95% confidence interval (CI) 1.7-12.8], esophageal atresia/stenosis (OR 4.6, 95% CI 1.8-12.2) and rectal/anal stenosis (OR 3.7, 95% CI 1.6-8.5) were higher in the offspring of pregnant women with PE+SCH. CONCLUSIONS PE in pregnant women was not associated with a higher risk of any congenital abnormalities in their offspring, but PE+SCH was associated with a higher risk of renal dysgenesis, esophageal atresia/stenosis and rectal/anal stenosis. These findings need confirmation in other studies.

Nano-intercalated rhodanese in cyanide antagonism

Abstract Present studies have focused on nano-intercalated rhodanese in combination with sulfur donors to prevent cyanide lethality in a prophylactic mice model for future development of an effective cyanide antidotal system. Our approach is based on the idea of converting cyanide to the less toxic thiocyanate before it reaches the target organs by utilizing sulfurtransferases (e.g., rhodanese) and sulfur donors in a close proximity by injecting them directly into the blood stream. The inorganic thiosulfate (TS) and the garlic component diallydisulfide (DADS) were compared as sulfur donors with the nano-intercalated rhodanese in vitro and in vivo. The in vivo and in vitro experiments showed that DADS is not a more efficient sulfur donor than TS. However, the utilization of external rhodanese significantly enhanced the in vivo efficacy of both sulfur donor-nitrite combinations, indicating the potential usefulness of enzyme nano-delivery systems in developing antidotal therapeutic agents.