Methods for Analysis of Matrix Metalloproteinase Regulation of Neutrophil-Endothelial Cell Adhesion

Recent evidence indicates novel role for matrix metalloproteinases (MMPs), in particular gelatinase A (MMP-2), in the regulation of vascular biology that are unrelated to their well-known proteolytic breakdown of matrix proteins. We have previously reported that MMP-2 can modulate vascular reactivity by cleavage of the Gly32-Leu33 bound in big endothelin-1 (ET-1) yielding a novel vasoactive peptide ET-1[1-32]. These studies were conducted to investigate whether gelatinolytic MMPs could affect neutrophil-endothelial cell attachment. ET-1[1-32] produced by MMP-2 up-regulated CD11b/CD18 expression on human neutrophils, thereby promoted their adhesion to cultured endothelial cells. ET-1[1-32] evoked release of gelatinase B (MMP-9), which in turn cleaved big ET-1 to yield ET-1[1-32], thus revealing a self-amplifying loop for ET-1[1-32] generation. ET-1[1-32] was rather resistant to cleavage by neutrophil proteases and further metabolism of ET-1[1-32] was not a prerequisite for its biological actions on neutrophils. The neutrophil responses to ET-1[1-32] were mediated via activation of ET(A)receptors through activation of the Ras/Raf-1/MEK/ERK signaling pathway. These results suggest a novel role for gelatinase A and B in the regulation of neutrophil functions and their interactions with endothelial cells. Here we describe the methods in detail as they relate to our previously published work

Intimate Pride: a Tri-Nation Study on Associations between Positive Minority Identity Aspects and Relationship Quality in Sexual Minorities from German-Speaking Countries

Investigations into the intimate relationships of sexual minorities are proliferating, but often adopt a deficit-oriented and US-centered perspective. In this tri-nation online study with sexual minority participants from Austria, Germany, and Switzerland (N = 571), we (i) assessed the construct validity of the German version of a well-known measure for positive minority identity aspects (the Lesbian, Gay, Bisexual Positive Identity Measure; LGB-PIM), and (ii) explored associations between these aspects (self-awareness, authenticity, community, capacity for intimacy, and social justice) and self-reported relationship quality. Model fit of the German version of the LGB-PIM was deemed acceptable. Higher levels of positive minority identity aspects showed small to moderate associations with higher levels of relationship quality in bivariate analyses, but only capacity for intimacy was linked to relationship quality in higher-order models (controlling for country, age, sexual orientation, gender identity, relationship length, and psychological distress). Results remained robust in several sensitivity analyses. Our results highlight the differential role of positive identity aspects for relationship functioning, with capacity for intimacy as a fruitful leverage point for therapeutic work

Generation tourism: towards a common identity

The purpose of this article is to highlight the implications of the indiscipline of tourism academia for a new generation of tourism academics. Generation Tourism is characterised by scholars with a multi-disciplinary education associated with a broad field of study and commonly considered to lack the advantages of a discipline-focused education with its strong theoretical and methodological foundations. The problem this article addresses relates to how new generations of scholars and their views on knowledge creation achieve ascendancy in ways that move on from existing paradigms and earlier cohorts of scholars. Our main argument is that Generation Tourism scholars would benefit from a more clearly developed and common academic identity. To begin the critical conversation around the identity of Generation Tourism we outline five possible points of departure. These points are: (1) learning from historical developments in parent disciplines; (2) spearheading inter-disciplinary scholarship; (3) working towards theoretical developments; (4) embracing mediating methodologies and (5) forming tourism nodes and networks. Recognising these as starting points rather than final statements, we hope that the conversation about Generation Tourism identity will continue in other forums

Internalisierte Transnegativität, Resilienzfaktoren und psychische Gesundheit in einer Stichprobe geschlechtlicher Minderheiten in Deutschland und der Schweiz

Zusammenfassung: Theoretischer Hintergrund: Trans*, inter* und nichtbinäre Personen erfahren Diskriminierung und weisen im Vergleich zur Gesamtpopulation eine höhere Prävalenz von affektiven und Angststörungen auf. Fragestellung: Diese präregistrierte Studie überprüft basierend auf dem Minderheiten-stressmodell den Zusammenhang zwischen Selbststigmatisierung (internalisierte Transnegativität) und psychischer Gesundheit und untersucht Resilienzfaktoren als Moderatoren. Methode: In einer Stichprobe deutscher und Schweizer trans*, inter* und nichtbinärer Personen ( N = 243) wurden multiple lineare Regressions- und Moderationsanalysen berechnet, um Zusammenhänge zwischen internalisierter Transnegativität und Angst- und depressiver Symptomatik sowie Resilienzfaktoren zu prüfen. Ergebnisse: Die Ergebnisse zeigen positive Zusammenhänge zwischen internalisierter Transnegativität und Angst- und depressiver Symptomatik. Die Resilienzfaktoren soziale Unterstützung und Verbundenheit mit der LGBT+ Community sind negativ mit internalisierter Transnegativität assoziiert. Keiner der Resilienzfaktoren moderierte die Zusammenhänge zwischen internalisierter Transnegativität und psychischer Gesundheit. Schlussfolgerungen: Die Studie bestätigt internationale Befunden zum Zusammenhang zwischen internalisierter Transnegativität und psychischer Gesundheit. Mehr Forschung ist nötig, um die Rolle der Resilienzfaktoren im Minderheitenstressmodell zu klären

Endothelin 1 levels in relation to clinical presentation and outcome of Henoch Schonlein purpura

<p>Abstract</p> <p>Background</p> <p>Henoch Schonlein purpura (HSP) is a common vasculitis of small vessels whereas endothelin-1 (ET-1) is usually reported elevated in vasculities and systematic inflammation. The aim of the present study was to investigate whether ET-1 levels are correlated with the clinical presentation and the outcome of HSP.</p> <p>Methods</p> <p>The study sample consisted of thirty consecutive patients with HSP. An equal number of healthy patients of similar age and the same gender were served as controls. The patients' age range was 2–12.6 years with a mean ± SD = 6.3 ± 3 years. All patients had a physical examination with a renal, and an overall clinical score. Blood and urinary biochemistry, immunology investigation, a skin biopsy and ET-1 measurements in blood and urine samples were made at presentation, 1 month later and 1 year after the appearance of HSP. The controls underwent the same investigation with the exception of skin biopsy.</p> <p>Results</p> <p>ET-1 levels in plasma and urine did not differ between patients and controls at three distinct time points. Furthermore the ET-1 were not correlated with the clinical score and renal involvement was independent from the ET-1 measurements. However, the urinary ET-1 levels were a significant predictor of the duration of the acute phase of HSP (HR = 0.98, p = 0.032, CI0.96–0.99). The ET-1 levels did not correlate with the duration of renal involvement.</p> <p>Conclusion</p> <p>Urinary ET-1 levels are a useful marker for the duration of the acute phase of HSP but not for the length of renal involvement.</p

The role of endothelin-1 in hyperoxia-induced lung injury in mice

BACKGROUND: As prolonged hyperoxia induces extensive lung tissue damage, we set out to investigate the involvement of endothelin-1 (ET-1) receptors in these adverse changes. METHODS: Experiments were performed on four groups of mice: control animals kept in room air and a group of mice exposed to hyperoxia for 60 h were not subjected to ET-1 receptor blockade, whereas the dual ETA/ETB-receptor blocker tezosantan (TEZ) was administered via an intraperitoneal pump (10 mg/kg/day for 6 days) to other groups of normal and hyperoxic mice. The respiratory system impedance (Zrs) was measured by means of forced oscillations in the anesthetized, paralyzed and mechanically ventilated mice before and after the iv injection of ET-1 (2 μg). Changes in the airway resistance (Raw) and in the tissue damping (G) and elastance (H) of a constant-phase tissue compartment were identified from Zrs by model fitting. RESULTS: The plasma ET-1 level increased in the mice exposed to hyperoxia (3.3 ± 1.6 pg/ml) relative to those exposed to room air (1.6 ± 0.3 pg/ml, p < 0.05). TEZ administration prevented the hyperoxia-induced increases in G (13.1 ± 1.7 vs. 9.6 ± 0.3 cmH(2)O/l, p < 0.05) and H (59 ± 9 vs. 41 ± 5 cmH(2)O/l, p < 0.05) and inhibited the lung responses to ET-1. Hyperoxia decreased the reactivity of the airways to ET-1, whereas it elevated the reactivity of the tissues. CONCLUSION: These findings substantiate the involvement of the ET-1 receptors in the physiopathogenesis of hyperoxia-induced lung damage. Dual ET-1 receptor antagonism may well be of value in the prevention of hyperoxia-induced parenchymal damage

Reduced Neutrophil Apoptosis in Diabetic Mice during Staphylococcal Infection Leads to Prolonged Tnfα Production and Reduced Neutrophil Clearance

Diabetes is a frequent underlying medical condition among individuals with Staphylococcus aureus infections, and diabetic patients often suffer from chronic inflammation and prolonged infections. Neutrophils are the most abundant inflammatory cells during the early stages of bacterial diseases, and previous studies have reported deficiencies in neutrophil function in diabetic hosts. We challenged age-matched hyperglycemic and normoglycemic NOD mice intraperitoneally with S. aureus and evaluated the fate of neutrophils recruited to the peritoneal cavity. Neutrophils were more abundant in the peritoneal fluids of infected diabetic mice by 48 h after bacterial inoculation, and they showed prolonged viability ex vivo compared to neutrophils from infected nondiabetic mice. These differences correlated with reduced apoptosis of neutrophils from diabetic mice and were dependent upon the presence of S. aureus and a functional neutrophil respiratory burst. Decreased apoptosis correlated with impaired clearance of neutrophils by macrophages both in vitro and in vivo and prolonged production of proinflammatory tumor necrosis factor alpha by neutrophils from diabetic mice. Our results suggest that defects in neutrophil apoptosis may contribute to the chronic inflammation and the inability to clear staphylococcal infections observed in diabetic patients

Therapeutic efficacy of TBC3711 in monocrotaline-induced pulmonary hypertension

Background: Endothelin-1 signalling plays an important role in pathogenesis of pulmonary hypertension. Although different endothelin-A receptor antagonists are developed, a novel therapeutic option to cure the disease is still needed. This study aims to investigate the therapeutic efficacy of the selective endothelin-A receptor antagonist TBC3711 in monocrotaline-induced pulmonary hypertension in rats. Methods: Monocrotaline-injected male Sprague-Dawley rats were randomized and treated orally from day 21 to 35 either with TBC3711 (Dose: 30 mg/kg body weight/day) or placebo. Echocardiographic measurements of different hemodynamic and right-heart hypertrophy parameters were performed. After day 35, rats were sacrificed for invasive hemodynamic and right-heart hypertrophy measurements. Additionally, histologic assessment of pulmonary vascular and right-heart remodelling was performed. Results: The novel endothelin-A receptor antagonist TBC3711 significantly attenuated monocrotaline-induced pulmonary hypertension, as evident from improved hemodynamics and right-heart hypertrophy in comparison with placebo group. In addition, muscularization and medial wall thickness of distal pulmonary vessels were ameliorated. The histologic evaluation of the right ventricle showed a significant reduction in fibrosis and cardiomyocyte size, suggesting an improvement in right-heart remodelling. Conclusion: The results of this study suggest that the selective endothelin-A receptor antagonist TBC3711 demonstrates therapeutic benefit in rats with established pulmonary hypertension, thus representing a useful therapeutic approach for treatment of pulmonary hypertension

Blood neutrophil activation markers in severe asthma: lack of inhibition by prednisolone therapy

BACKGROUND: Neutrophils are increased in the airways and in induced sputum of severe asthma patients. We determined the expression of activation markers from circulating neutrophils in severe asthma, and their supressibility by corticosteroids. METHODS: We compared blood neutrophils from mild, moderate-to-severe and severe steroid-dependent asthma, and non-asthmatics (n = 10 each). We examined the effect of adding or increasing oral prednisolone (30 mg/day;1 week). RESULTS: Flow cytometric expression of CD35 and CD11b, but not of CD62L or CD18, was increased in severe asthma. F-met-leu-phe increased CD11b, CD35 and CD18 and decreased CD62L expression in all groups, with a greater CD35 increase in severe asthma. In severe steroid-dependent asthma, an increase in prednisolone dose had no effect on neutrophil markers particularly CD62L, but reduced CD11b and CD62L on eosinophils. Phorbol myristate acetate-stimulated oxidative burst and IL-8 release by IL-1β, lipopolysaccharide and GM-CSF in whole blood from mild but not severe asthmatics were inhibited after prednisolone. There were no differences in myeloperoxidase or neutrophil elastase release from purified neutrophils. CONCLUSION: Because blood neutrophils in severe asthma are activated and are not inhibited by oral corticosteroids, they may be important in the pathogenesis of severe asthma