Pro-inflammatory alterations and status of blood plasma iron in a model of blast-induced lung trauma

Mechanisms of microRNA-132 in central neurodegenerative diseases: A comprehensive review

MicroRNA-132 (miR-132) is a highly conserved molecule that plays a crucial regulatory role in central nervous system (CNS) disorders. The expression levels of miR-132 exhibit variability in various neurological disorders and have been closely linked to disease onset and progression. The expression level of miR-132 in the CNS is regulated by a diverse range of stimuli and signaling pathways, including neuronal migration and integration, dendritic outgrowth, and complexity, synaptogenesis, synaptic plasticity, as well as inflammation and apoptosis activation. The aberrant expression of miR-132 in various central neurodegenerative diseases has garnered widespread attention. Clinical studies have revealed altered miR-132 expression levels in both chronic and acute CNS diseases, positioning miR-132 as a potential biomarker or therapeutic target. An in-depth exploration of miR-132 holds the promise of enhancing our understanding of the mechanisms underlying CNS diseases, thereby offering novel insights and strategies for disease diagnosis and treatment. It is anticipated that this review will assist researchers in recognizing the potential value of miR-132 and in generating innovative ideas for clinical trials related to CNS degenerative diseases.

High risk and low prevalence diseases: Blast injuries

INTRODUCTION

Blast injury is a unique condition that carries a high rate of morbidity and mortality, often with mixed penetrating and blunt injuries.

OBJECTIVE

This review highlights the pearls and pitfalls of blast injuries, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Explosions may impact multiple organ systems through several mechanisms. Patients with suspected blast injury and multisystem trauma require a systematic evaluation and resuscitation, as well as investigation for injuries specific to blast injuries. Blast injuries most commonly affect air-filled organs but can also result in severe cardiac and brain injury. Understanding blast injury patterns and presentations is essential to avoid misdiagnosis and balance treatment of competing interests of patients with polytrauma. Management of blast victims can also be further complicated by burns, crush injury, resource limitation, and wound infection. Given the significant morbidity and mortality associated with blast injury, identification of various injury patterns and appropriate management are essential.

CONCLUSIONS

An understanding of blast injuries can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Nebulised recombinant activated factor VII (rFVIIa) does not attenuate the haemorrhagic effects of blast lung injury

Introduction

Primary blast lung injury causes intrapulmonary haemorrhage. A number of case reports have suggested the efficacy of recombinant activated factor VII (rFVIIa) in the treatment of diffuse alveolar haemorrhage from a range of medical causes, but its efficacy in blast lung is unknown. The aim of this study was to investigate whether nebulised rFVIIa attenuates the haemorrhagic effects of blast lung injury in an animal model.

Methods

Terminally anaesthetised rabbits subjected to blast lung injury were randomised to receive either rFVIIa or placebo via a nebuliser. The primary outcome was the level of blood iron–transferrin complex, a marker of the extent of blast lung injury, analysed using low temperature electron paramagnetic resonance spectroscopy.

Results

Blast exposure led to a significant fall in iron-bound transferrin in both groups of animals (p<0.001), which remained depressed during the study. There were no significant differences in iron–transferrin between the rFVIIa and placebo treatment groups over the duration of the study (p=0.081), and there was no trend towards elevated iron–transferrin in the rFVIIa-treated group once drug treatment had started. There was suggestive evidence of systemic absorption of rFVIIa given via the inhaled route.

Conclusion

A single dose of nebulised rFVIIa did not attenuate pulmonary haemorrhage in a rabbit model of blast lung injury. As there was some evidence of systemic absorption, the inhaled route does not avoid the concern about potential thromboembolic complications from administration of rFVIIa.

Pathophysiology of primary blast injury

The majority of patients injured in the recent conflicts in Iraq and Afghanistan were as a result of explosion, and terrorist incidents have brought blast injuries to the front door of many civilian hospitals that had not previously encountered such devastation. This article reviews the physics and pathophysiology of blast injury with particular relevance to the presentation and management of primary blast injury, which is the mechanism least familiar to most clinicians and which may cause devastating injury without externals signs.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

Physiological and proteomic responses to corticosteroid treatments in Eurasian perch, Perca fluviatilis: Investigation of immune-related parameters

The comparative effects of cortisol and 11-deoxycorticosterone (DOC), two major corticosteroids in fish, have yet received little attention in teleosts. We evaluated the proteomic and immune responses of Eurasian perch to chronic corticosteroid treatments. We implanted immature perch with cortisol (80mg/kg) or DOC (4mg/kg) and measured the proportions of blood leucocytes, immune indices in the plasma, spleen and liver (complement and lysozyme activity, total immunoglobulin and immune gene expression in the tissues) and differential proteome expression (corticosteroid versus control) in the liver and the spleen on days 2, 4 and 14 post-treatment. Implantation of cortisol decreased the ratio of blood leucocytes and depressed Ig levels in both organs while DOC modulated the proportion of leucocyte sub-populations (increase in lymphocytes and decrease in granulocytes). In contrast, the innate humoral immunity was not strongly influenced by any of corticosteroid implants. The only immune parameter that was significantly affected was lysozyme, after DOC treatment. A number of proteins were differentially regulated by these hormones and some were identified in the liver (21 for cortisol and 8 for DOC) and in the spleen (10 for cortisol and 10 for DOC). None of the proteins was directly linked to immunity, except the natural killer enhancing factor, which was repressed by cortisol in the spleen. Our results also confirm that the proteins involved in energetic and glucose metabolism are affected by corticosteroids. Furthermore, these corticosteroids differently regulate immune status in Eurasian perch and they primarily impact leucocytes, as opposed to innate immune function.

The role of neutrophil gelatinase-associated lipocalin (NGAL) in the detection of blast lung injury in a military population

PURPOSE

To study the relationship between serum neutrophil gelatinase-associated lipocalin (NGAL) and military blast and gunshot wound (GSW) to establish whether potential exists for NGAL as a biomarker for blast lung injury (BLI).

METHOD

Patients from the intensive care unit (ICU) of the Role 3 Medical Treatment Facility at Camp Bastion, Helmand Province, Afghanistan were studied over a five month period commencing in 2012. Age, mechanism, trauma injury severity score (TRISS) and serum NGAL were recorded on ICU admission (NGAL1). Serum NGAL (NGAL2) and PaO₂/FiO₂ ratio (P/F ratio2) were recorded at 24h.

RESULTS

33 patients were injured by blast and 23 by GSW. NGAL1 inversely correlated with TRISS (p=0.020), pH (p=0.002) and P/F ratio 2 (p=0.009) overall. When data was stratified into blast and GSW, NGAL1 also inversely correlated with P/F ratio 2 in the blast injured group (p=0.008) but not GSW group (p=0.27).

CONCLUSION

Raised NGAL correlated with increased severity of injury (worse survival probability i.e. TRISS and low pH) in both patient groups. There was an inverse correlation between admission NGAL and a marker of blast lung injury (low P/F ratio) at 24h in blast injured group but not GSW group that warrants further investigation.

The Role of C-Reactive Protein in Mood Disorders

Recently, a possible relationship between C-Reactive Protein (CRP), a marker of underlying low-grade inflammation, and mood disorders has been proposed by some researchers. The aim of this review is to elucidate the current facts and views about CRP in mood disorders such as Depressive and Bipolar Disorders. Several studies have examined the relationship between affective disorders and CRP, but the majority of the studies in literature have been limited by retrospective, case-controlled study design, and very few studies have examined the relationship between depression and CRP in large study samples. In conclusion, the role of CRP in mood disorders is, to date, intriguing but somewhat unclear. Further prospective studies are needed to introduce the CRP in clinical settings as a marker of affective states and suicidability.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

What's New in Traumatic Brain Injury: Update on Tracking, Monitoring and Treatment

Traumatic brain injury (TBI), defined as an alteration in brain functions caused by an external force, is responsible for high morbidity and mortality around the world. It is important to identify and treat TBI victims as early as possible. Tracking and monitoring TBI with neuroimaging technologies, including functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), positron emission tomography (PET), and high definition fiber tracking (HDFT) show increasing sensitivity and specificity. Classical electrophysiological monitoring, together with newly established brain-on-chip, cerebral microdialysis techniques, both benefit TBI. First generation molecular biomarkers, based on genomic and proteomic changes following TBI, have proven effective and economical. It is conceivable that TBI-specific biomarkers will be developed with the combination of systems biology and bioinformation strategies. Advances in treatment of TBI include stem cell-based and nanotechnology-based therapy, physical and pharmaceutical interventions and also new use in TBI for approved drugs which all present favorable promise in preventing and reversing TBI.

Haemodynamic changes in trauma

Trauma is the leading cause of death during the first four decades of life in the developed countries. Its haemodynamic response underpins the patient's initial ability to survive, and the response to treatment and subsequent morbidity and resolution. Trauma causes a number of insults including haemorrhage, tissue injury (nociception) and, predominantly, in military casualties, blast from explosions. This article discusses aspects of the haemodynamic responses to these insults and subsequent treatment. 'Simple' haemorrhage (blood loss without significant volume of tissue damage) causes a biphasic response: mean arterial blood pressure (MBP) is initially maintained by the baroreflex (tachycardia and increased vascular resistance, Phase 1), followed by a sudden decrease in MAP initiated by a second reflex (decrease in vascular resistance and bradycardia, Phase 2). Phase 2 may be protective. The response to tissue injury attenuates Phase 2 and may cause a deleterious haemodynamic redistribution that compromises blood flow to some vital organs. In contrast, thoracic blast exposure augments Phase 2 of the response to haemorrhage. However, hypoxaemia from lung injury limits the effectiveness of hypotensive resuscitation by augmenting the attendant shock state. An alternative strategy ('hybrid resuscitation') whereby tissue perfusion is increased after the first hour of hypotensive resuscitation by adopting a revised normotensive target may ameliorate these problems. Finally, morphine also attenuates Phase 2 of the response to haemorrhage in some, but not all, species and this is associated with poor outcome. The impact on human patients is currently unknown and is the subject of a current physiological investigation.

Glycyrrhizin represses total parenteral nutrition-associated acute liver injury in rats by suppressing endoplasmic reticulum stress

Total parenteral nutrition (TPN) is an artificial way to support daily nutritional requirements by bypassing the digestive system, but long-term TPN administration may cause severe liver dysfunction. Glycyrrhizin is an active component of licorice root that has been widely used to treat chronic hepatitis. The aim of this study is to investigate the hepatoprotective effect of glycyrrhizin on TPN-associated acute liver injury in vivo. Liver dysfunction was induced by intravenous infusion of TPN at a flow rate of 20 mL/kg/h for three h in Sprague Dawley rats. The rats were pretreated with Glycyrrhizin (1, 3 and 10 mg/kg intravenously). After receiving TPN or saline (control group) for three h, the rats were sacrificed, blood samples were collected for biochemical analyses and liver tissue was removed for histopathological and immunohistochemical examination. We found that aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TB) and triglyceride (TG) levels were significantly increased in the TPN group without glycyrrhizin pretreatment and decreased in the glycyrrhizin-pretreated TPN group in a dose-dependent manner. The stained liver sections showed that glycyrrhizin relieved acute liver injury. The upregulation of serum protein biomarkers of reactive nitrogen species, including nitrotyrosine and inducible NO synthase (iNOS), were attenuated by glycyrrhizin pretreatment. Levels of endoplasmic reticulum (ER) stress factors, such as phosphorylation of JNK1/2, p38 MAPK and CHOP, were decreased by glycyrrhizin pretreatment. In summary, our results suggest that glycyrrhizin decreases TPN-associated acute liver injury factors by suppressing endoplasmic reticulum stress and reactive nitrogen stress.

Contribution of systemic factors in the pathophysiology of repeated blast-induced neurotrauma

Blast-induced traumatic brain injury is complex and involves multiple factors including systemic pathophysiological factors in addition to direct brain injuries. We hypothesize that systemic activation of platelets/leukocytes plays a major role in the development and exacerbation of brain injury after blast exposure. A mouse model of repeated blast exposure that results in significant neuropathology, neurobehavioral changes and regional specific alterations in various biomolecules in the brain was used for the proposed study. Activation of platelets was evaluated by flow cytometry and serotonin content was analyzed by ELISA. Expression of myeloperoxidase was analyzed by Western blotting. Histopathology of the brain was used to assess blast-induced cerebral vasoconstriction. The data showed an increase in the activation of platelets at 4h after repeated blast exposures, indicating changes in platelet phenotype in blast neurotrauma. Platelet serotonin concentration showed a significant decrease at 4h after blast with a concurrent increase in the plasma serotonin levels, confirming the early onset of platelet activation after repeated blast exposures. Blood, plasma and brain myeloperoxidase enzyme activity and expression was increased in repeated blast exposed mice at multiple time points. Histopathological analysis of the brains of blast exposed mice showed constriction of blood vessels compared to the respective controls, a phenomenon similar to the reported cerebral vasoconstriction in blast affected victims. These results suggest that repeated blast exposure leads to acute activation of platelets/leukocytes which can augment the pathological effects of brain injury. Platelet/leukocyte targeted therapies can be evaluated as potential acute treatment strategies to mitigate blast-induced neurotrauma.

Modulation of cholinergic pathways and inflammatory mediators in blast-induced traumatic brain injury

Cholinergic activity has been recognized as a major regulatory component of stress responses after traumatic brain injury (TBI). Centrally acting acetylcholinesterase (AChE) inhibitors are also being considered as potential therapeutic candidates against TBI mediated cognitive impairments. We have evaluated the expression of molecules involved in cholinergic and inflammatory pathways in various regions of brain after repeated blast exposures in mice. Isoflurane anesthetized C57BL/6J mice were restrained and placed in a prone position transverse to the direction of the shockwaves and exposed to three 20.6 psi blast overpressures with 1-30 min intervals. Brains were collected at the 6h time point after the last blast exposure and subjected to cDNA microarray and microRNA analysis. cDNA microarray analysis showed significant changes in the expression of cholinergic (muscarinic and nicotinic) and gammaaminobutyric acid and glutamate receptors in the midbrain region along with significant changes in multiple genes involved in inflammatory pathways in various regions of the brain. MicroRNA analysis of cerebellum revealed differential expression of miR-132 and 183, which are linked to cholinergic anti-inflammatory signaling, after blast exposure. Changes in the expression of myeloperoxidase in the cerebellum were confirmed by Western blotting. These results indicate that early pathologic progression of blast TBI involves dysregulation of cholinergic and inflammatory pathways related genes. Acute changes in molecules involved in the modulation of cholinergic and inflammatory pathways after blast TBI can cause long-term central and peripheral pathophysiological changes.

A Multiscale Approach to Blast Neurotrauma Modeling: Part II: Methodology for Inducing Blast Injury to in vitro Models

Due to the prominent role of improvised explosive devices (IEDs) in wounding patterns of U.S. war-fighters in Iraq and Afghanistan, blast injury has risen to a new level of importance and is recognized to be a major cause of injuries to the brain. However, an injury risk-function for microscopic, macroscopic, behavioral, and neurological deficits has yet to be defined. While operational blast injuries can be very complex and thus difficult to analyze, a simplified blast injury model would facilitate studies correlating biological outcomes with blast biomechanics to define tolerance criteria. Blast-induced traumatic brain injury (bTBI) results from the translation of a shock wave in-air, such as that produced by an IED, into a pressure wave within the skull-brain complex. Our blast injury methodology recapitulates this phenomenon in vitro, allowing for control of the injury biomechanics via a compressed-gas shock tube used in conjunction with a custom-designed, fluid-filled receiver that contains the living culture. The receiver converts the air shock wave into a fast-rising pressure transient with minimal reflections, mimicking the intracranial pressure history in blast. We have developed an organotypic hippocampal slice culture model that exhibits cell death when exposed to a 530 ± 17.7-kPa peak overpressure with a 1.026 ± 0.017-ms duration and 190 ± 10.7 kPa-ms impulse in-air. We have also injured a simplified in vitro model of the blood-brain barrier, which exhibits disrupted integrity immediately following exposure to 581 ± 10.0 kPa peak overpressure with a 1.067 ± 0.006-ms duration and 222 ± 6.9 kPa-ms impulse in-air. To better prevent and treat bTBI, both the initiating biomechanics and the ensuing pathobiology must be understood in greater detail. A well-characterized, in vitro model of bTBI, in conjunction with animal models, will be a powerful tool for developing strategies to mitigate the risks of bTBI.

The epidemiology of blast lung injury during recent military conflicts: a retrospective database review of cases presenting to deployed military hospitals, 2003-2009

Blast injuries are becoming increasingly common in military conflicts as the nature of combat changes from conventional to asymmetrical warfare and counter-insurgency. This article describes a retrospective database review of cases from the UK joint theatre trauma registry from 2003 to 2009, containing details of over 3000 patients, mainly injured in Iraq and Afghanistan. During this period, 1678 patients were injured by explosion of whom 113 had evidence of blast lung injury. Of the 50 patients who survived to reach a medical facility, 80 per cent required ventilatory support. Injuries caused by explosion are increasing when compared with those caused by other mechanisms, and blast lung represents a significant clinical problem in a deployed military setting. Management of these patients should be optimized from point of wounding to definitive care.

Characterization of the response to primary blast injury

Lung injuries, predominantly arising from blast exposure, are a clinical problem in a significant minority of current military casualties. This special feature consists of a series of articles on lung injury. This first article examines the mechanism of the response to blast lung (primary blast injury to the lung). Subsequent articles examine the incidence of blast lung, clinical consequences and current concepts of treatment, computer (in silico) modelling of lung injury and finally chemical injuries to the lungs. Blast lung is caused by a shock wave generated by an explosion causing widespread damage in the lungs, leading to intrapulmonary haemorrhage. This, and the ensuing inflammatory response in the lung, leads to a compromise in pulmonary gas exchange and hypoxia that can worsen over several hours. There is also a characteristic cardio-respiratory effect mediated via an autonomic reflex causing apnoea (or rapid shallow breathing), bradycardia and hypotension (the latter possibly also due to the release of nitric oxide). An understanding of this response, and the way it modifies other reflexes, can help the development of new treatment strategies for this condition and for the way it influences the patient's response to concomitant injuries.

Spatial coordination of cell-adhesion molecules and redox cycling of iron in the microvascular inflammatory response to pulmonary injury

Transmigration of phagocytic leukocytes (PLCs) from the peripheral blood into injured lung requires a conversion of the microvascular endothelial cells (ECs) to the proinflammatory phenotypes and spatiotemporal interplay of different types of cell adhesion molecules (CAMs) on PLC and endothelium. The present report is focused on involvement of iron-dependent redox signaling in spatial coordination of lung CAM due to either a pulmonary trauma or endotracheal iron administration in rats. Redox alterations, deposition of 3-nitrotyrosine, expression of VE-cadherin, ICAM-1, and the PLC integrins, and the status of thioredoxin, Ref-1, NF-kappaB and Nrf2 redox-sensitive elements in the alveolar microvasculature were assessed with EPR spectroscopy, immunobloting, and confocal microscopy. We demonstrated for the first time in vivo that the presence of catalytically active iron, deposition of myeloperoxidase, and induction of the oxidative stress in the lung-injury models were accompanied by (a) downregulation of VE-cadherin, (b) upregulation and polarization of ICAM-1 and the PLC integrins, and (c) nuclear translocation and interaction of thioredoxin, Ref-1, and NF-kappaB and complex structural changes in EC and PLC at the sites of their contacts. The studies suggested that a part of the proinflammatory action of iron in the lung resulted from its stimulation of the redox-sensitive factors.

IL-1beta induces alkaline phosphatase in human phagocytes

BACKGROUND

Alkaline phosphatase (ALPase) is found in blood plasma or serum and leukocytes and regulates intercellular processes, maintaining phosphoryl metabolites in a steady state, as well as synthesizing and hydrolyzing phosphate esters on membranes. ALPase supervises the active transport of inorganic phosphates, fats, proteins, carbohydrates and the sodium/potassium pump mechanisms. The formed elements of blood such as polymorphonuclear (PMNs) leucocytes, macrophages (MP) and some lymphocytes are high in ALPase concentrations.

METHODS

In this study we have tested whether the interleukin-1 receptor antagonist (IL-lra) could influence ALPase generation in IL-1beta or lipopolysaccharide (LPS)-stimulated neutrophils and MP. Human neutrophils were isolated from heparin-anticoagulated blood drawn from healthy individuals by centrifugation in a two-step gradient, Ficoll-Hypaque. ALPase activity was assessed spectrophotometrically in test tubes containing isolated neutrophils and adherence PBMCs treated with LPS, IL-1beta and IL-1ra, alone or in combination.

RESULTS

IL-lbeta or LPS enhanced ALPase in both PMNs and MP, whereas IL-1ra could not inhibit ALPase activity. We performed time course experiments at 0 min, 5 min, 1 h, 24 h, and 43 h (LPS 20 microg/mL, IL-1beta 10 ng/mL). No significant increase in ALPase activity was seen until 1 h; however, there was a rapid rise over the next few hours. In another set of experiments using IL-1ra (500 ng/mL), there was no difference between treated cells and control cells. The combination of IL-1beta plus IL-1ra did not reduce the ability of IL-1beta to induce ALPase activity.

CONCLUSIONS

These data suggest that IL-1beta stimulates ALPase through other mechanisms than the release of arachidonic acid products, which are inhibited by IL-lra.

Expression and secretion of RANTES (CCL5) in granulomatous calcified tissue before and after lipopolysaccharide treatment in vivo

RANTES (regulated on activation, normal T cell-expressed and secreted) is a CC chemokine appearing to be involved in the recruitment of leukocytes at inflammation sites. RANTES is produced by CD8(+) T cells, epithelial cells, fibroblasts, and platelets. It acts in vitro in leukocyte activation and human immunodeficiency virus suppression, but its role in vivo is still uncertain. In our study, we established the involvement of RANTES in an in vivo model of chronic inflammation induced by potassium permanganate, leading to calcified granulomas. In our rat model, RANTES expression (mRNA and protein) was significantly upregulated in granulomatous tissue; RANTES expression was further increased upon i.p. injection of lipopolysaccharide (LPS), while it was kept at basal levels by dexamethasone (Dex) given 18 hours before sacrifice. LPS and Dex increased and decreased, respectively, the recruitment of mononuclear cells in granulomatous tissue compared with control granulomas from phosphate-buffered saline (PBS)-treated animals. In granuloma tissue, levels of RANTES were higher in LPS-treated rats and lower in the Dex group compared to controls. RANTES was also found in the conditioned medium of granuloma tissue from treated (LPS or Dex) and untreated (PBS) rats. When LPS was added in vitro for 18 hours, RANTES was further increased, except in the Dex group (P > 0.05). On serum analysis, RANTES levels were higher in the LPS group and lower in the Dex group compared to controls. This study shows for the first time that RANTES is produced in vivo in chronic, experimental inflammatory states, an effect increased by LPS and inhibited by Dex.

Pulmonary biochemical and histological alterations after repeated low-level blast overpressure exposures

Blast overpressure (BOP), also known as high energy impulse noise, is a damaging outcome of explosive detonations and firing of weapons. Exposure to BOP shock waves alone results in injury predominantly to the hollow organ systems such as auditory, respiratory, and gastrointestinal systems. In recent years, the hazards of BOP that once were confined to military and professional settings have become a global societal problem as terrorist bombings and armed conflicts involving both military and civilian populations increased significantly. We have previously investigated the effects of single BOP exposures at different peak pressures. In this study, we examined the effects of repeated exposure to a low-level BOP and whether the number of exposures or time after exposure would alter the injury outcome. We exposed deeply anesthetized rats to simulated BOP at 62 +/- 2 kPa peak pressure. The lungs were examined immediately after one exposure (1 + 0), or 1 h after one (1 + 1), two (2 + 1), or three (3 + 1) consecutive exposures at 3-min interval. In one group of animals, we examined the effects of repeated exposure on lung weight, methemoglobin, transferrin, antioxidants, and lipid peroxidation. In a second group, the lungs were fixed inflated at 25 cm water, sectioned, and examined histologically after one to three repeated exposures, or after one exposure at 1, 6, and 24 h. We found that single BOP exposure causes notable changes after 1 h, and that repeating BOP exposure did not add markedly to the effect of the first one. However, the effects increased significantly with time from 1 to 24 h. These observations have biological and occupational implications, and emphasize the need for protection from low-level BOP, and for prompt treatment within the first hour following BOP exposure.

Lung Injury and Recovery After Exposure to Blast Overpressure

BACKGROUND

A critical immediate determinant of survival after exposure to blast overpressure (BOP) is pulmonary damage, but mechanisms of injury and the course of recovery are not well understood. The objective of this study was to characterize the progression of oxidative and inflammatory responses in lungs as well as the activation of consequent protective mechanisms after exposure to medium intensity BOP.

METHODS

Rats were exposed to a moderate (approximately 120 kPa) level of BOP in a pneumatically driven shock tube. At different times (2-192 hours) after exposure, lungs were examined for pathologic signs of injury, markers of inflammatory responses, and indicators of oxidative and nitrative damage.

RESULTS

The results showed a postblast activation of inflammatory response (increase of myeloperoxidase activity, CINC-1, ICAM-1, and iNOS), increase in protein oxidation and nitration, and development of gross diffused hemorrhage in lungs. The initial phase of lung damage that peaked at 24 to 48 hours after exposure to BOP was followed by gradual dissolution of inflammation and oxidation that were complete by 192 hours. Resolution of morphologic damage and inflammation in lungs concurred with activation of expression of antioxidant enzymes heme oxygenase-1 (HO-1) and manganese superoxide dismutase (MnSOD). Plasma level of gelsolin, a marker of acute lung damage was decreased at 24 hours postblast and later returned to the control level.

CONCLUSIONS

The study shows the role of adaptive anti-oxidant and anti- inflammatory mechanisms in lung recovery after injury caused by exposure to BOP.

Inhibitory effect of quercetin on tryptase and MCP-1 chemokine release, and histidine decarboxylase mRNA transcription by human mast cell-1 cell line

Mast cells are important in reactions of allergic disease and are also involved in a variety of neuroinflammatory diseases. Mast cells can be immunologically activated by IgE through their Fc receptors, as well as by neuropeptides and cytokines to secrete mediators. Here we used a human mast cell-1 (HMC-1) cell line cultured and treated with a physiological activator, anti-IgE, and a nonphysiological activator, calcium ionophore A23187, for tryptase and MCP-1 generation and transcription of histidine decarboxylase. We used quercetin, a potent antioxidant, cytoprotective and anti-inflammatory compound capable of inhibiting histamine and some cytokines released from several cell types, as an inhibitor of immunological and nonimmunological stimulus for mast cells. In this study quercetin inhibits, in a dose-response manner, tryptase and MCP-1. Moreover, using RT-PCR quercetin inhibited the transcription of histidine decarboxylase, the rate-limiting enzyme responsible for the generation of histamine from histidine, and MCP-1. Our data suggest that quercetin is an important and good candidate for reducing the release of pro-inflammatory mast cell mediators activated by physiological and nonphysiological stimulators.

Inflammatory leukocytes and iron turnover in experimental hemorrhagic lung trauma

To monitor cascade of events following alveolar extravasation of blood due to exposure to shock wave (SW), we conducted spatiotemporal assessment of myeloperoxidase (MPO), heme oxygenase 1 (HO-1), Cu,Zn superoxide dismutase (SOD-1), transferrin (TRF), 3-nitrotyrosine (3NTyr), alveolar endothelial cadherin (VE-CDH), and the CD11b adhesion molecules on leukocytes using electron microscopy, electron paramagnetic resonance spectroscopy, immunofluorescence imaging, and immunoblotting. Accumulation of HO-1, MPO, 3NTyr, and SOD-1 in HIL at the first 12 h was associated with transmigration of inflammatory leucocytes (ILK) into hemorrhagic lesions (HLs). Biodegradation of extravasated hemoglobin (exvHb) and deposition of iron in alveoli occurred at 3-56 h post-exposure and was preceded by LKC degranulation and accumulation of MPO, HO-1, and SOD-1 in HLs. These alterations were accompanied by appearance of heme and non-heme iron complexes in HLs. A significant increase in TRF-bound [Fe(3+)] (i.e., 14.6 +/- 5.3 microM vs. 4.8 +/- 2.1 microM immediately after exposure) and non-TRF complexes of [Fe(3+)] (i.e., 4.5 +/- 1.8 microM vs. < 0.3 microM immediately after exposure) occurred at 24 h post-exposure. Transmigrations of ILK, nitroxidative stress, and iron deposition in endothelial and epithelial cells were accompanied by destruction of endothelial integrity at 3 h post-exposure, and alveolar capillary network and necrotic changes in the pulmonary epithelial cells at 24-56 h post-exposure.