Care Med Research Articles

Halogenated Anesthetics Impairs Biophysical Properties of a Membrane Model of Pulmonary Surfactant

Pulmonary surfactant (PS) is a complex mixture of lipids and proteins responsible to protect the lung tissue from mechanical stress during ventilation, by decreasing alveolar surface tension. Indeed, an appropriate PS function is critical in order to avoid alveolar collapse. There are many causes that produce PS dysfunction, lung damage and alveolar collapse. Our aim was to explore the effect of Halogenated Anesthetics on functional PS. Sevoflurane is widely used in different protocols of anesthesia. However, there is little evidence of the mechanisms that could explain the damage in alveolar space observed in animal models (1). In the present study we evaluate the effect of Sevoflurane in a mixture of synthetic lipids (50:50, DPPC:PC and 20% mol Cholesterol) as a model of PS. Spectroscopic tools were used to determine membrane interface polarity and internal fluidity (dipolar relaxation and anisotropy). Generalized Polarization (3wGP) was determined by the use of Prodan probe in liposome mixtures with and without Sevoflurane and membrane interface polarity was evaluated at different temperatures (20-46°C). In a second set of experiments, we studied the effect of Sevoflurane on the internal core of liposomes, following changes in anisotropy of added diphenylhexatriene. Our results indicate that Sevoflurane (0.3-0.9 mM) increased the 3wGP at temperatures above 30ºC. As a consequence, the melting temperature has an increase of 1-2ºC. This effect, accompanied by changes in the anisotropy could explain in part our previous observations “in vivo”(1). Further research will be needed to have a better understanding of the biophysical mechanism involved. (1) L. Malacrida et al. Am. J. Respir. Crit. Care Med. 181;2010:A3631.

T Cell Receptor Clonotype Influences Epitope Hierarchy in the CD8+ T Cell Response to Respiratory Syncytial Virus Infection

CD8+ T cell responses are important for recognizing and resolving viral infections. To better understand the selection and hierarchy of virus-specific T cell responses, we compared the T cell receptor (TCR) clonotype in parent and hybrid strains of respiratory syncytial virus-infected mice. K(d)M2(82-90) (SYIGSINNI) in BALB/c and D(b)M(187-195) (NAITNAKII) in C57Bl/6 are both dominant epitopes in parent strains but assume a distinct hierarchy, with K(d)M2(82-90) dominant to D(b)M(187-195) in hybrid CB6F1/J mice. The dominant K(d)M2(82-90) response is relatively public and is restricted primarily to the highly prevalent Vβ13.2 in BALB/c and hybrid mice, whereas D(b)M(187-195) responses in C57BL/6 mice are relatively private and involve multiple Vβ subtypes, some of which are lost in hybrids. A significant frequency of TCR CDR3 sequences in the D(b)M(187-195) response have a distinct "(D/E)WG" motif formed by a limited number of recombination strategies. Modeling of the dominant epitope suggested a flat, featureless structure, but D(b)M(187-195) showed a distinctive structure formed by Lys(7). The data suggest that common recombination events in prevalent Vβ genes may provide a numerical advantage in the T cell response and that distinct epitope structures may impose more limited options for successful TCR selection. Defining how epitope structure is interpreted to inform T cell function will improve the design of future gene-based vaccines.

Antimicrobial Peptides Increase Tolerance to Oxidant Stress in Drosophila melanogaster

It is well appreciated that reactive oxygen species (ROS) are deleterious to mammals, including humans, especially when generated in abnormally large quantities from cellular metabolism. Whereas the mechanisms leading to the production of ROS are rather well delineated, the mechanisms underlying tissue susceptibility or tolerance to oxidant stress remain elusive. Through an experimental selection over many generations, we have previously generated Drosophila melanogaster flies that tolerate tremendous oxidant stress and have shown that the family of antimicrobial peptides (AMPs) is over-represented in these tolerant flies. Furthermore, we have also demonstrated that overexpression of even one AMP at a time (e.g. Diptericin) allows wild-type flies to survive much better in hyperoxia. In this study, we used a number of experimental approaches to investigate the potential mechanisms underlying hyperoxia tolerance in flies with AMP overexpression. We demonstrate that flies with Diptericin overexpression resist oxidative stress by increasing antioxidant enzyme activities and preventing an increase in ROS levels after hyperoxia. Depleting the GSH pool using buthionine sulfoximine limits fly survival, thus confirming that enhanced survival observed in these flies is related to improved redox homeostasis. We conclude that 1) AMPs play an important role in tolerance to oxidant stress, 2) overexpression of Diptericin changes the cellular redox balance between oxidant and antioxidant, and 3) this change in redox balance plays an important role in survival in hyperoxia.

Fibrinogen concentrate for management of bleeding

Fibrinogen concentrate for management of bleeding

Translational Research Efforts in Biomarkers and Biology of Early Transplant-Related Complications

In the time since the first allogeneic hematopoietic stem cell transplantation (HSCT) was performed over 40 years ago, this life-saving procedure has been used increasingly for patients with hematologic, metabolic, and malignant diseases. Despite major advances in our understanding of the immunologic processes (both beneficial and injurious) that are associated with HSCT and improvements in supportive and critical care medicine, successful outcomes are still limited by several serious complications. As such, the establishment of effective therapeutic strategies for these complications will be crucial as increasing numbers of high-risk transplants are performed each year. The development of such approaches is fundamentally dependent upon a basic understanding of pathophysiologic mechanisms of disease and also on our ability to successfully translate these insights back to the bedside. This brief review will highlight breakthroughs in translational research endeavors that have paved the way for the development of novel strategies intended to change the standard of care and optimize outcomes for patients in whom allogeneic HSCT offers the only hope for a cure.

Sphingolipid-mediated Inhibition of Apoptotic Cell Clearance by Alveolar Macrophages

A decreased clearance of apoptotic cells (efferocytosis) by alveolar macrophages (AM) may contribute to inflammation in emphysema. The up-regulation of ceramides in response to cigarette smoking (CS) has been linked to AM accumulation and increased detection of apoptotic alveolar epithelial and endothelial cells in lung parenchyma. We hypothesized that ceramides inhibit the AM phagocytosis of apoptotic cells. Release of endogenous ceramides via sphingomyelinase or exogenous ceramide treatments dose-dependently impaired apoptotic Jurkat cell phagocytosis by primary rat or human AM, irrespective of the molecular species of ceramide. Similarly, in vivo augmentation of lung ceramides via intratracheal instillation in rats significantly decreased the engulfment of instilled target apoptotic thymocytes by resident AM. The mechanism of ceramide-induced efferocytosis impairment was dependent on generation of sphingosine via ceramidase. Sphingosine treatment recapitulated the effects of ceramide, dose-dependently inhibiting apoptotic cell clearance. The effect of ceramide on efferocytosis was associated with decreased membrane ruffle formation and attenuated Rac1 plasma membrane recruitment. Constitutively active Rac1 overexpression rescued AM efferocytosis against the effects of ceramide. CS exposure significantly increased AM ceramides and recapitulated the effect of ceramides on Rac1 membrane recruitment in a sphingosine-dependent manner. Importantly, CS profoundly inhibited AM efferocytosis via ceramide-dependent sphingosine production. These results suggest that excessive lung ceramides may amplify lung injury in emphysema by causing both apoptosis of structural cells and inhibition of their clearance by AM.

Do IFN-γ-release assays predict the risk of TB? New evidence from a study on patients with silicosis

Evaluation of: Leung CC, Yam WC, Yew WW et al. T-SPOT.TB outperforms tuberculin skin test in predicting tuberculosis disease. Am. J. Respir. Crit. Care Med. DOI: 10.1164/rccm.200912-1875OC (2010) (Epub ahead of print).IFN-γ-release assays (IGRAs) are new tools for the diagnosis of latent TB infection which, until recently, relied only on the use of the tuberculin skin test (TST). However, while the positive predictive value of a positive TST for active TB is well established, little evidence on this issue is available for IGRAs. In a study conducted on silicosis patients in Hong Kong, China, Leung et al. found that a positive response to an IGRA, the T-SPOT.TB, was associated with a larger than fourfold increase in the risk of developing TB compared with those who tested negative, while a smaller than twofold increase was observed for TST-positives compared with negatives. This study provides further support to the guidelines from public health agencies recommending the use of IGRAs in place of or in addition to TST. Several issues regarding their optimal use, however, remain open to debate.

Probiotics for the prevention of ventilator-associated pneumonia

Evaluation of: Morrow LE, Kollef MH, Casale TB. Probiotic prophylaxis of ventilator-associated pneumonia: a blinded, randomized, controlled trial. Am. J. Respir. Crit. Care Med. DOI: 10.1164/rccm.200912-1853OC (2010) (Epub ahead of print).In a recently conducted randomized double-blind placebo-controlled trial, probiotics were compared with placebo in mechanically ventilated patients at risk for ventilator-associated pneumonia (VAP). Microbiologically documented VAP, Clostridium difficile-associated diarrhea and colonization by pathogenic bacteria were less frequent in probiotic-treated patients. We used this opportunity to update a relevant meta-analysis of similar trials. Using a random-effects model, we found a nonsignificant trend towards a lower incidence of VAP in patients treated with a probiotic formulation versus controls (seven studies, 994 patients; pooled odds ratio: 0.60; 95% CI: 0.35–1.02); all-cause mortality did not differ (six studies, 786 patients; odds ratio: 0.84; 95% CI: 0.59–1.18).

Immunomodulatory cell therapy in sepsis: have we learnt lessons from the past?

Evaluation of: Mei SH, Haitsma JJ, Dos Santos CC et al. Mesenchymal stem cells reduce inflammation while enhancing bacterial clearance and improving survival in sepsis. Am. J. Respir. Crit. Care Med. DOI: 10.1164/rccm.201001-0010OC (2010) (Epub ahead of print).Sepsis still constitutes a public health challenge worldwide since its incidence constantly increases over time but its related mortality remains more or less constant. There is thus an unquestionable and urgent need to develop innovative and efficacious therapies for the treatment of this deadly disease. In this study, the authors propose that injection of mesenchymal stem cells rescues mice from death after septic shock owing to their potent immunosuppressive and anti-inflammatory properties. The authors conclude that immunomodulatory cell therapy may represent an effective treatment for sepsis. While the potential therapeutic value of these cells is not to be challenged, considering the present lack of convincing data about mesenchymal stem cell use in sepsis, we do not believe that they constitute the next topical clinical trial in the field. Rather, recent evidence indicates that most septic patients actually present with profound immune alterations suggesting that anti-inflammatory approaches could deleteriously amplify this state. Therefore, in this article, we propose hypotheses explaining why the future of clinical trials in sepsis immunology will likely rely on stimulating immune functions for rebalancing immune homeostasis.

Increased Glucocorticoid Receptor Expression and Activity Mediate the LPS Resistance of SPRET/EI Mice

SPRET/Ei mice are extremely resistant to acute LPS-induced lethal inflammation when compared with C57BL/6. We found that in vivo SPRET/Ei mice exhibit strongly reduced expression levels of cytokines and chemokines. To investigate the role of the potent anti-inflammatory glucocorticoid receptor (GR) in the SPRET/Ei phenotype, mice were treated with the GR antagonist RU486 or bilateral adrenalectomy. Under such conditions, both C57BL/6 and SPRET/Ei mice were strongly sensitized to LPS, and the differences in LPS response between SPRET/Ei and C57BL/6 mice were completely gone. These results underscore the central role of GR in the LPS hyporesponsiveness of SPRET/Ei mice. Compared with C57BL/6, SPRET/Ei mice were found to express higher GR levels, which were reflected in increased GR transactivation. Using a backcross mapping strategy, we demonstrate that the high GR transcription levels are linked to the Nr3c1 (GR) locus on chromosome 18 itself. Unexpectedly, SPRET/Ei mice exhibit a basal overactivation of the hypothalamic-pituitary-adrenal axis, namely strongly increased corticosterone levels, ACTH levels, and adrenocortical size. As a consequence of the excess of circulating glucocorticoids (GCs), levels of hepatic gluconeogenic enzymes are increased, and insulin secretion from pancreatic β-cells is impaired, both of which result in hyperglycemia and glucose intolerance in SPRET/Ei mice. We conclude that SPRET/Ei mice are unique as they display an unusual combination of elevated GR expression and increased endogenous GC levels. Hence, these mice provide a new and powerful tool for the study of GR- and GC-mediated mechanisms, including immune repressive functions, neuroendocrine regulation, insulin secretion, and carbohydrate metabolism.

Cot/tpl2 (MAP3K8) Mediates Myeloperoxidase Activity and Hypernociception following Peripheral Inflammation*

Cot/tpl2 (also known as MAP3K8) has emerged as a new and potentially interesting therapeutic anti-inflammatory target. Here, we report the first study of Cot/tpl2 involvement in acute peripheral inflammation in vivo. Six hours after an intraplantar injection of zymosan, Cot/tpl2(-/-) mice showed a 47% reduction in myeloperoxidase activity, concomitant with a 46% lower neutrophil recruitment and a 40% decreased luminol-mediated bioluminescence imaging in vivo. Accordingly, Cot/tpl2 deficiency provoked a 25-30% reduction in luminol-mediated bioluminescence and neutrophil recruitment together with a 65% lower macrophage recruitment 4 h following zymosan-induced peritonitis. Significantly impaired levels of G-CSF and GM-CSF and of other cytokines such as TNFα, IL-1β, and IL-6, as well as some chemokines such as MCP-1, MIP-1β, and keratinocyte-derived chemokine, were detected during the acute zymosan-induced intraplantar inflammatory response in Cot/tpl2(-/-) mice. Moreover, Cot/tpl2 deficiency dramatically decreased the production of the hypernociceptive ligand NGF at the inflammatory site during the course of inflammation. Most importantly, Cot/tpl2 deficiency significantly reduced zymosan-induced inflammatory hypernociception in mice, with a most pronounced effect of a 50% decrease compared with wild type (WT) at 24 h following intraplantar injection of zymosan. At this time, Cot/tpl2(-/-) mice showed significantly reduced NGF, TNFα, and prostaglandin E(2) levels compared with WT littermates. In conclusion, our study demonstrates an important role of Cot/tpl2 in the NGF, G-CSF, and GM-CSF production and myeloperoxidase activity in the acute inflammatory response process and its implication in inflammatory hypernociception.

Loss of Function of Transient Receptor Potential Vanilloid 1 (TRPV1) Genetic Variant Is Associated with Lower Risk of Active Childhood Asthma

Transient receptor potential cation channels of the vanilloid subfamily (TRPV) participate in the generation of Ca(2+) signals at different locations of the respiratory system, thereby controlling its correct functioning. TRPV1 expression and activity appear to be altered under pathophysiological conditions such as chronic cough and airway hypersensitivity, whereas TRPV4 single nucleotide polymorphisms (SNP) are associated with chronic obstructive pulmonary disease. However, to date, there is no information about the genetic impact of either TRPV1 or TRPV4 on asthma pathophysiology. We now report on the association of two functional SNPs, TRPV1-I585V and TRPV4-P19S, with childhood asthma. Both SNPs were genotyped in a population of 470 controls without respiratory symptoms and 301 asthmatics. Although none of the SNPs modified the risk of suffering from asthma, carriers of the TRPV1-I585V genetic variant showed a lower risk of current wheezing (odds ratio = 0.51; p = 0.01), a characteristic of active asthma, or cough (odds ratio = 0.57; p = 0.02). Functional analysis of TRPV1-I585V, using the Ca(2+)-sensitive dye fura-2 to measure intracellular [Ca(2+)] concentrations, revealed a decreased channel activity in response to two typical TRPV1 stimuli, heat and capsaicin. On the other hand, TRPV4-P19S, despite its loss-of-channel function, showed no significant association with asthma or the presence of wheezing. Our data suggest that genetically determined level of TRPV1 activity is relevant for asthma pathophysiology.

Der p 5 Crystal Structure Provides Insight into the Group 5 Dust Mite Allergens

Group 5 allergens from house dust mites elicit strong IgE antibody binding in mite-allergic patients. The structure of Der p 5 was determined by x-ray crystallography to better understand the IgE epitopes, to investigate the biologic function in mites, and to compare with the conflicting published Blo t 5 structures, designated 2JMH and 2JRK in the Protein Data Bank. Der p 5 is a three-helical bundle similar to Blo t 5, but the interactions of the helices are more similar to 2JMH than 2JRK. The crystallographic asymmetric unit contains three dimers of Der p 5 that are not exactly alike. Solution scattering techniques were used to assess the multimeric state of Der p 5 in vitro and showed that the predominant state was monomeric, similar to Blo t 5, but larger multimeric species are also present. In the crystal, the formation of the Der p 5 dimer creates a large hydrophobic cavity of approximately 3000 A(3) that could be a ligand-binding site. Many allergens are known to bind hydrophobic ligands, which are thought to stimulate the innate immune system and have adjuvant-like effects on IgE-mediated inflammatory responses.

Risk of stroke from sleep apnea in men and women

Evaluation of: Redline S, Yenokyan G, Gottlieb D et al. Evaluation of obstructive sleep apnea hypopnea and incident stroke: The Sleep Heart Health Study. Am. J. Respir. Crit. Care Med. DOI: 10.1164/rccm.200911-1746OC (2010).Obstructive sleep apnea (OSA) is a common sleep disorder, and research on the effects of sleep apnea is important to gain insight into how sleep affects health. Untreated OSA has been associated with important health consequences, such as an increased risk for hypertension, cardiovascular disease and diabetes. Previous studies have shown that OSA also represents a risk factor for stroke. The relationship between OSA and stroke is particularly relevant, as stroke is the second leading cause of death globally. The reviewed article presents new data from the Sleep Heart Health Study, a longitudinal cohort study, which shows an association between incident stroke and untreated OSA of varying severity for men and possibly more severe OSA for women. The study is discussed in the context of the current state of knowledge about OSA, in particular its health consequences, and the general limitations in conducting research with OSA patients.

Zinc Released from Injured Cells Is Acting via the Zn2+-sensing Receptor, ZnR, to Trigger Signaling Leading to Epithelial Repair

A role for Zn(2+) in accelerating wound healing is established, yet, the signaling pathways linking Zn(2+) to tissue repair are not well known. We show that in the human HaCaT keratinocytes extracellular Zn(2+) induces a metabotropic Ca(2+) response that is abolished by silencing the expression of the G-protein-coupled receptor GPR39, suggesting that this Zn(2+)-sensing receptor, ZnR, is mediating the response. Keratinocytic-ZnR signaling is highly selective for Zn(2+) and can be triggered by nanomolar concentrations of this ion. Interestingly, Zn(2+) was also released following cellular injury, as monitored by a specific non-permeable fluorescent Zn(2+) probe, ZnAF-2. Chelation of Zn(2+) and scavenging of ATP from conditioned medium, collected from injured epithelial cultures, was sufficient to eliminate the metabotropic Ca(2+) signaling. The signaling triggered by Zn(2+), via ZnR, or by ATP further activated MAP kinase and induced up-regulation of the sodium/proton exchanger NHE1 activity. Finally, activation of ZnR/GPR39 signaling or application of ATP enhanced keratinocytes scratch closure in an in vitro model. Thus our results indicate that extracellular Zn(2+), which is either applied or released following injury, activates ZnR/GPR39 to promote signaling leading to epithelial repair.

The International Society of Heart and Lung Transplantation Guidelines for the care of heart transplant recipients

Institutional Affiliations Chair Costanzo MR: Midwest Heart Foundation, Lombard Illinois, USA Task Force 1 Dipchand A: Hospital for Sick Children, Toronto Ontario, Canada; Starling R: Cleveland Clinic Foundation, Cleveland, Ohio, USA; Anderson A: University of Chicago, Chicago, Illinois, USA; Chan M: University of Alberta, Edmonton, Alberta, Canada; Desai S: Inova Fairfax Hospital, Fairfax, Virginia, USA; Fedson S: University of Chicago, Chicago, Illinois, USA; Fisher P: Ochsner Clinic, New Orleans, Louisiana, USA; Gonzales-Stawinski G: Cleveland Clinic Foundation, Cleveland, Ohio, USA; Martinelli L: Ospedale Niguarda, Milano, Italy; McGiffin D: University of Alabama, Birmingham, Alabama, USA; Parisi F: Ospedale Pediatrico Bambino Gesu, Rome, Italy; Smith J: Freeman Hospital, Newcastle upon Tyne, UK Task Force 2 Taylor D: Cleveland Clinic Foundation, Cleveland, Ohio, USA; Meiser B: University of Munich/Grosshaden, Munich, Germany; Baran D: Newark Beth Israel Medical Center, Newark, New Jersey, USA; Carboni M: Duke University Medical Center, Durham, North Carolina, USA; Dengler T: University of Hidelberg, Heidelberg, Germany; Feldman D: Minneapolis Heart Institute, Minneapolis, Minnesota, USA; Frigerio M: Ospedale Niguarda, Milano, Italy; Kfoury A: Intermountain Medical Center, Murray, Utah, USA; Kim D: University of Alberta, Edmonton, Alberta, Canada; Kobashigawa J: Cedar-Sinai Heart Institute, Los Angeles, California, USA; Shullo M: University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Stehlik J: University of Utah, Salt Lake City, Utah, USA; Teuteberg J: University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Uber P: University of Maryland, Baltimore, Maryland, USA; Zuckermann A: University of Vienna, Vienna, Austria. Task Force 3 Hunt S: Stanford University, Palo Alto, California, USA; Burch M: Great Ormond Street Hospital, London, UK; Bhat G: Advocate Christ Medical Center, Oak Lawn, Illinois, USA; Canter C: St. Louis Children Hospital, St. Louis, Missouri, USA; Chinnock R: Loma Linda University Children's Hospital, Loma Linda, California, USA; Crespo-Leiro M: Hospital Universitario A Coruna, La Coruna, Spain; Delgado R: Texas Heart Institute, Houston, Texas, USA; Dobbels F: Katholieke Universiteit Leuven, Leuven, Belgium; Grady K: Northwestern University, Chicago, Illlinois, USA; Kao W: University of Wisconsin, Madison Wisconsin, USA; Lamour J: Montefiore Medical Center, New York, New York, USA; Parry G: Freeman Hospital, Newcastle upon Tyne, UK; Patel J: Cedar-Sinai Heart Institute, Los Angeles, California, USA; Pini D: Istituto Clinico Humanitas, Rozzano, Italy; Pinney S: Mount Sinai Medical Center, New York, New York, USA; Towbin J: Cincinnati Children's Hospital, Cincinnati, Ohio, USA; Wolfel G: University of Colorado, Denver, Colorado, USA Independent Reviewers Delgado D: University of Toronto, Toronto, Ontario, Canada; Eisen H: Drexler University College of Medicine, Philadelphia, Pennsylvania, USA; Goldberg L: University of Pennsylvania, Philadelphia, Pennsylvania, USA; Hosenpud J: Mayo Clinic, Jacksonville, Florida, USA; Johnson M: University of Wisconsin, Madison, Wisconsin, USA; Keogh A: St Vincent Hospital, Sidney, New South Wales, Australia; Lewis C: Papworth Hospital Cambridge, UK; O'Connell J: St. Joseph Hospital, Atlanta, Georgia, USA; Rogers J: Duke University Medical Center, Durham, North Carolina, USA; Ross H: University of Toronto, Toronto, Ontario, Canada; Russell S: Johns Hopkins Hospital, Baltimore, Maryland, USA; Vanhaecke J: University Hospital Gasthuisberg, Leuven, Belgium.

Use of a Single-Chain Antibody Library for Ovarian Cancer Biomarker Discovery

The discovery of novel early detection biomarkers of disease could offer one of the best approaches to decrease the morbidity and mortality of ovarian and other cancers. We report on the use of a single-chain variable fragment antibody library for screening ovarian serum to find novel biomarkers for the detection of cancer. We alternately panned the library with ovarian cancer and disease-free control sera to make a sublibrary of antibodies that bind proteins differentially expressed in cancer. This sublibrary was printed on antibody microarrays that were incubated with labeled serum from multiple sets of cancer patients and controls. The antibodies that performed best at discriminating disease status were selected, and their cognate antigens were identified using a functional protein microarray. Overexpression of some of these antigens was observed in cancer serum, tumor proximal fluid, and cancer tissue via dot blot and immunohistochemical staining. Thus, our use of recombinant antibody microarrays for unbiased discovery found targets for ovarian cancer detection in multiple sample sets, supporting their further study for disease diagnosis.

Dendritic cell vaccination as a treatment modality for mesothelioma

Evaluation of: Hegmans JP, Veltman JD, Lambers ME et al. Consolidative dendritic cell-based immunotherapy elicits cytotoxicity against malignant mesothelioma. Am. J. Respir. Crit. Care Med. DOI: 10.1164/rccm.200909-1465OC (2010) (Epub ahead of print).Malignant mesothelioma is caused by the neoplastic transformation of mesothelial cells and occurs predominantly in the pleura, but also less frequently in the peritoneum, pericardium or tunica vaginalis testis. Exposure to asbestos, a mineral fiber, is the major causative factor. Median survival is approximately 9 months from the onset of clinical symptoms. Median survival is only increased by about 2 months after treatment with currently validated chemotherapy, with the median time to progression also increased by 2 months. All other therapeutic strategies have shown no, or limited, survival benefit. Because of the limited success of conventional treatments, novel therapeutic regimens are being investigated, including immunotherapy. A new vaccine, developed as an adjuvant to chemotherapy in the treatment of malignant mesothelioma, was described in a recent issue of The American Journal of Respiratory and Critical Care Medicine. This vaccine has been proposed to induce the activation of an immune response against the cancer cells. A group from The Netherlands has demonstrated that this immunotherapy is able to favor an anti-tumor response, associated with objective clinical evidence.

Invited Commentary

Invited Commentary

Inhibition of Glycogen Synthase Kinase 3β (GSK3β) Decreases Inflammatory Responses in Brain Endothelial Cells

Immune mediators and leukocyte engagement of brain microvascular endothelial cells (BMVECs) contribute to blood-brain barrier impairment during neuroinflammation. Glycogen synthase kinase 3beta (GSK3beta) was recently identified as a potent regulator of immune responses in in vitro systems and animal models. However, the role of GSK3beta in regulation of immune endothelial functions remains undetermined. Here we evaluated the effect of GSK3beta inhibition on the regulation of inflammatory responses in BMVECs. A focused PCR gene array of 84 genes was performed to identify the cytokine and chemokine gene expression profile in tumor necrosis factor (TNF) alpha-stimulated BMVECs after GSK3beta inactivation by specific inhibitors. Fifteen of 39 genes induced by TNFalpha stimulation were down-regulated after GSK3beta inhibition. Genes known to contribute to neuroinflammation that were most negatively affected by GSK3beta inactivation included IP-10/CXCL10, MCP-1/CCL2, IL-8/CXCL8, RANTES/CCL5, and Groalpha/CXCL1. GSK3beta suppression resulted in diminished secretion of these proinflammatory mediators by inflamed BMVECs detected by ELISA. GSK3beta inhibition in BMVECs reduced adhesion molecule expression as well as monocyte adhesion to and migration across cytokine stimulated BMVEC monolayers. Interactions of monocytes with TNFalpha-activated BMVECs led to barrier disruption, and GSK3beta suppression in the endothelium restored barrier integrity. GSK3beta inhibition in vivo substantially decreased leukocyte adhesion to brain endothelium under inflammatory conditions. In summary, inhibition of GSK3beta emerges as an important target for stabilization of the blood-brain barrier in neuroinflammation.