Role of P-selectin in platelet sequestration in pulmonary capillaries during endotoxemia

Background: There is growing evidence that platelets accumulate in the lung and contribute to the pathogenesis of acute lung injury during endotoxemia. The aims of the present study were to localize platelet sequestration in the pulmonary microcirculation and to investigate the role of P-selectin as a molecular mechanism of platelet endothelial cell interaction. Methods: We used in vivo fluorescence microscopy to quantify the kinetics of fluorescently labeled erythrocytes and platelets in alveolar capillary networks in rabbit lungs. Results: Six hours after onset of endotoxin infusion we observed a massive rolling along and firm adherence of platelets to lung capillary endothelial cells whereas under control conditions no platelet sequestration was detected. P-selectin was expressed on the surface of separated platelets which were incubated with endotoxin and in lung tissue. Pretreatment of platelets with fucoidin, a P-selectin antagonist, significantly attenuated the endotoxin-induced platelet rolling and adherence. In contrast, intravenous infusion of fucoidin in endotoxin-treated rabbits did not inhibit platelet sequestration in pulmonary capillaries. Conclusion: We conclude that platelets accumulate in alveolar capillaries following endotoxemia. P-selectin expressed on the surface of platelets seems to play an important role in mediating this platelet-endothelial cell interaction. Copyright (c) 2006 S. Karger AG, Basel

Effectiveness of first and second-line empirical treatment in Italy: Results of the European registry on Helicobacter pylori management.

Background and aims: The optimal management of naïve and not naïve Helicobacter pylori patients remains unclear. Therefore, it is essential to evaluate whether the actual clinical practice mirrors the indications suggested by the guidelines. This study aimed to assess the effectiveness and the safety of the empirical first- and second-line treatments prescribed to patients enroled at Italian centres participating in the European Registry on H. pylori Management (Hp-EuReg). Methods: The Hp-EuReg is an international multicentre prospective non-interventional registry starting in 2013 aiming to evaluate the management of H. pylori infection by European gastroenterologists. Patients were registered in an e-CRF by AEG-REDCap. Variables assessed included demographics, previous eradication attempts, treatment regimen, effectiveness, and tolerance. Results: Overall, 3723 patients from 2013 to February 2021 were included: 2996 and 727 received an empirical first- and second-line treatment, respectively. According to the modified ITT analysis, among the first-line regimens, only the bismuth quadruple therapy with three-in-one-single capsule (BQT-TSC), the concomitant, and the sequential treatment - all lasting 10 days - achieved an eradication rate >90%. Among the second-line regimens, only the 10-day BQT-TSC reported an effectiveness >90%. High-dose PPI twice daily also significantly increased the effectiveness of some therapies. The BQT-TSC was the regimen with the highest incidence of adverse events. Conclusions: Only quadruple therapies lasting at least 10 days achieved over 90% eradication rates among the empirical first- and second-line regimens. It remains unclear whether high-dose PPI twice daily can improve the efficacy of quadruple treatment

Changes in bone marrow lesions in response to weight-loss in obese knee osteoarthritis patients: a prospective cohort study

BACKGROUND: Patients are susceptible for knee osteoarthritis (KOA) with increasing age and obesity and KOA is expected to become a major disabling disease in the future. An important feature of KOA on magnetic resonance imaging (MRI) is changes in the subchondral bone, bone marrow lesions (BMLs), which are related to the future degeneration of the knee joint as well as prevalent clinical symptoms. The aim of this study was to investigate the changes in BMLs after a 16-week weight-loss period in obese subjects with KOA and relate changes in BMLs to the effects of weight-loss on clinical symptoms. METHODS: This prospective cohort study included patients with a body mass index ≥ 30 kg/m(2), an age ≥ 50 years and primary KOA. Patients underwent a 16 weeks supervised diet program which included formula products and dietetic counselling (ClinicalTrials.gov: NCT00655941). BMLs in tibia and femur were assessed on MRI before and after the weight-loss using the Boston-Leeds Osteoarthritis Knee Score. Response to weight-loss in BML scores was dichotomised to patients experiencing a decrease in BML scores (responders) and patients who did not (non-responders). The association of BMLs to weight-loss was assessed by logistic regressions and correlation analyses. RESULTS: 39 patients (23%) were classified as responders in the sum of all BML size scores whereas 130 patients (77%) deteriorated or remained stable and were categorized as non-responders. Logistic regression analyses revealed no association between weight-loss < or ≥ 10% and response in BMLs in the most affected compartment (OR 1.86 [CI 0.66 to 5.26, p=0.24]). There was no association between weight-loss and response in maximum BML score (OR 1.13 [CI 0.39 to 3.28, p=0.81]). The relationship between changes in BMLs and clinical symptoms revealed that an equal proportion of patients classified as BML responders and non-responders experienced an OMERACT-OARSI response (69 vs. 71%, p=0.86). CONCLUSIONS: Weight-loss did not improve the sum of tibiofemoral BML size scores or the maximum tibiofemoral BML score, suggesting that BMLs do not respond to a rapidly decreased body weight. The missing relationship between clinical symptoms and BMLs calls for further investigation

Guanosine stimulates neurite outgrowth in PC12 cells via activation of heme oxygenase and cyclic GMP

Undifferentiated rat pheochromocytoma (PC12) cells extend neurites when cultured in the presence of nerve growth factor (NGF). Extracellular guanosine synergistically enhances NGF-dependent neurite outgrowth. We investigated the mechanism by which guanosine enhances NGF-dependent neurite outgrowth. Guanosine administration to PC12 cells significantly increased guanosine 3-5-cyclic monophosphate (cGMP) within the first 24 h whereas addition of soluble guanylate cyclase (sGC) inhibitors abolished guanosine-induced enhancement of NGF-dependent neurite outgrowth. sGC may be activated either by nitric oxide (NO) or by carbon monoxide (CO). \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$N^{\omega }$$ \end{document}-Nitro-l-arginine methyl ester (l-NAME), a non-isozyme selective inhibitor of nitric oxide synthase (NOS), had no effect on neurite outgrowth induced by guanosine. Neither nNOS (the constitutive isoform), nor iNOS (the inducible isoform) were expressed in undifferentiated PC12 cells, or under these treatment conditions. These data imply that NO does not mediate the neuritogenic effect of guanosine. Zinc protoporphyrin-IX, an inhibitor of heme oxygenase (HO), reduced guanosine-dependent neurite outgrowth but did not attenuate the effect of NGF. The addition of guanosine plus NGF significantly increased the expression of HO-1, the inducible isozyme of HO, after 12 h. These data demonstrate that guanosine enhances NGF-dependent neurite outgrowth by first activating the constitutive isozyme HO-2, and then by inducing the expression of HO-1, the enzymes responsible for CO synthesis, thus stimulating sGC and increasing intracellular cGMP

Infected erythrocyte-derived extracellular vesicles alter vascular function via regulatory Ago2-miRNA complexes in malaria

Malaria remains one of the greatest public health challenges worldwide, particularly in sub-Saharan Africa. The clinical outcome of individuals infected with Plasmodium falciparum parasites depends on many factors including host systemic inflammatory responses, parasite sequestration in tissues and vascular dysfunction. Production of pro-inflammatory cytokines and chemokines promotes endothelial activation as well as recruitment and infiltration of inflammatory cells, which in turn triggers further endothelial cell activation and parasite sequestration. Inflammatory responses are triggered in part by bioactive parasite products such as hemozoin and infected red blood cell-derived extracellular vesicles (iRBC-derived EVs). Here we demonstrate that such EVs contain functional miRNA-Argonaute 2 complexes that are derived from the host RBC. Moreover, we show that EVs are efficiently internalized by endothelial cells, where the miRNA-Argonaute 2 complexes modulate target gene expression and barrier properties. Altogether, these findings provide a mechanistic link between EVs and vascular dysfunction during malaria infection

Analyzing GPCR-Ligand Interactions with the Fragment Molecular Orbital (FMO) Method

G-protein-coupled receptors (GPCRs) have enormous physiological and biomedical importance, and therefore it is not surprising that they are the targets of many prescribed drugs. Further progress in GPCR drug discovery is highly dependent on the availability of protein structural information. However, the ability of X-ray crystallography to guide the drug discovery process for GPCR targets is limited by the availability of accurate tools to explore receptor-ligand interactions. Visual inspection and molecular mechanics approaches cannot explain the full complexity of molecular interactions. Quantum mechanics (QM) approaches are often too computationally expensive to be of practical use in time-sensitive situations, but the fragment molecular orbital (FMO) method offers an excellent solution that combines accuracy, speed, and the ability to reveal key interactions that would otherwise be hard to detect. Integration of GPCR crystallography or homology modelling with FMO reveals atomistic details of the individual contributions of each residue and water molecule toward ligand binding, including an analysis of their chemical nature. Such information is essential for an efficient structure-based drug design (SBDD) process. In this chapter, we describe how to use FMO in the characterization of GPCR-ligand interactions

Water-induced modulation of Helicobacter pylori virulence properties

While the influence of water in Helicobacter pylori culturability and membrane integrity has been extensively studied, there are little data concerning the effect of this environment on virulence properties. Therefore, we studied the culturability of water-exposed H. pylori and determined whether there was any relation with the bacterium’s ability to adhere, produce functional components of pathogenicity and induce inflammation and alterations in apoptosis in an experimental model of human gastric epithelial cells. H. pylori partially retained the ability to adhere to epithelial cells even after complete loss of culturability. However, the microorganism is no longer effective in eliciting in vitro host cell inflammation and apoptosis, possibly due to the non-functionality of the cag type IV secretion system. These H. pylori-induced host cell responses, which are lost along with culturability, are known to increase epithelial cell turnover and, consequently, could have a deleterious effect on the initial H. pylori colonisation process. The fact that adhesion is maintained by H. pylori to the detriment of other factors involved in later infection stages appears to point to a modulation of the physiology of the pathogen after water exposure and might provide the microorganism with the necessary means to, at least transiently, colonise the human stomach.FCT (SFRH/BD/24579/2005) (to NMG

Analysis of antimicrobial susceptibility and virulence factors in Helicobacter pylori clinical isolates

BACKGROUND: In this study, we evaluated the prevalence of primary resistance of Brazilian H. pylori isolates to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone. In addition, the vacA, iceA, cagA and cagE genotypes of strains isolated from Brazilian patients were determined and associated with clinical data in an effort to correlate these four virulence markers and antibiotic resistance. METHODS: H. pylori was cultured in 155 H. pylori-positive patients and MICs for metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone were determined by the agar dilution method. Genomic DNA was extracted, and allelic variants of vacA, iceA, cagA and cagE were identified by the polymerase chain reaction. RESULTS: There was a strong association between the vacA s1/cagA -positive genotype and peptic ulcer disease (OR = 5.42, 95% CI 2.6–11.3, p = 0.0006). Additionally, infection by more virulent strains may protect against GERD, since logistic regression showed a negative association between the more virulent strain, vacA s1/cagA-positive genotype and GERD (OR = 0.26, 95% CI 0.08–0.8, p = 0.03). Resistance to metronidazole was detected in 75 patients (55%), to amoxicillin in 54 individuals (38%), to clarithromycin in 23 patients (16%), to tetracycline in 13 patients (9%), and to furazolidone in 19 individuals (13%). No significant correlation between pathogenicity and resistance or susceptibility was detected when MIC values for each antibiotic were compared with different vacA, iceA, cagA and cagE genotypes. CONCLUSION: The analysis of virulence genes revealed a specific association between H. pylori strains and clinical outcome, furthermore, no significant association was detected among pathogenicity and resistance or susceptibility

Helicobacter pylori infection might be responsible for the interconnection between type 1 diabetes and autoimmune thyroiditis

<p>Abstract</p> <p>Background</p> <p>Higher serological prevalence rates of helicobacter pylori (H. pylori) infection have been reported in patients with type 1 diabetes (T1DM) and autoimmune thyroiditis (AT). Patients with T1DM are at increased risk for developing other autoimmune diseases, most commonly AT. It is unknown whether H. pylori infection could explain the high prevalence of thyroid autoantibodies and AT in T1DM. The aim of the current study was to evaluate anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) autoantibodies in correlation with anti-H. pylori IgG and IgA in young patients with T1DM.</p> <p>Methods</p> <p>Anti-H. Pylori IgG, IgA, anti-TPO and anti-Tg antibodies titers were measured in 162 euthyroid patients with T1DM and 80 healthy controls matched for age, sex and socioeconomic status.</p> <p>Results</p> <p>Seroprevalence of H. pylori was significantly higher in patients with T1DM than in healthy controls; 79% vs. 51.2%, p < 0.001. Anti H. pylori IgG was positive in 61.1% of patients with T1DM and 30% of controls, p < 0.001, anti H. pylori IgA was positive in 74% of patients with T1DM and 32.5% of controls, p < 0.001. Thyroid autoimmunity was also significantly higher in patients with T1DM than in controls; 56.7% vs. 6.2%, p < 0.001. Anti-TPO was positive in 25.3% of patients with T1DM and 3.7% of controls, p < 0.001, anti-Tg was positive in 47.5% of patients with T1DM and 6.2% of controls, p < 0.001. With simple and multiple regression analysis anti-H. pylori IgG and IgA titers were positively and significantly correlated with Anti-TPO and anti-Tg titers in patients with T1DM.</p> <p>Conclusion</p> <p>our results support the idea of a connection between H. pylori infection and the occurrence of anti-TPO, anti-Tg autoantibodies and AT in young patients with T1DM. So, H. pylori infection could be considered as an environmental trigger for development of AT in T1DM. Young patients with T1DM should be screened for H. pylori infection.</p