Inflammation & Allergy-Drug Targets (Discontinued) - Volume 12, Issue 5, 2013

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen, which is the major cause of severe chronic lung infection in cystic fibrosis patients. It is also responsible for systemic infections in immunocompromised individuals and those presenting with significant pulmonary conditions in intensive care units. This microorganism has the capacity to initiate severe inflammation in infected lungs resulting in detrimental tissue damage. We have hypothesized that Syk protein tyrosine kinase mediates lung epithelial cellular responses to P. aeruginosa infection, and that a naturally occurring non-toxic Syk inhibitor piceatannol can protect infected human cells against the deleterious effects associated with this infection. We infected Syk-positive H292 or Syk-negative A549 human lung epithelial cell lines with P. aeruginosa and assessed the resulting cellular responses, i.e. production of proinflammatory cytokines, adhesion molecule expression, generation of reactive oxygen species, and apoptosis of infected cells, utilizing a multiplex bead-based immunoassay and flow cytometry. We also studied the internalization of P. aeruginosa using the gentamicin exclusion assay. We found that the piceatannol treatment significantly suppressed inflammation, oxidative stress and apoptosis in H292, but not in A549 cells implicating Syk participation in the regulation of the pathological processes induced by P. aeruginosa infection. Intriguingly, piceatannol was able to down-regulate the internalization of P. aeruginosa by both Syk-positive and Syk-negative cell lines, implying that the mechanisms of action of this compound extend beyond Syk inhibition. As piceatannol can interfere with several mechanisms of bacterial pathogenesis this natural compound deserves further study as a potential therapeutic option in P. aeruginosa infection.

Accumulating evidence suggests that Green tea polyphenolic catechins, especially the (-)-epigallocatechin gallate (EGCG), can be cross-linked to many proteins, and confer a wide range of anti-bacterial activities possibly by damaging microbial cytoplasmic lipids and proteins. At the doses that conferred protection against lethal polymicrobial infection (induced by cecal ligation and puncture), EGCG significantly reduced bacterial loads particularly in the liver and lung. To elucidate its bactericidal mechanisms, we determined whether EGCG affected the fluorescence intensities of bacteria-conjugated Alexa Fluor 488 or 594 dyes. When mixed with unconjugated Alexa Fluor 488 or 594 dyes, EGCG or analogs did not affect the fluorescence intensity of these dyes. In a sharp contrast, EGCG and some analogs (e.g., Catechin Gallate, CG), markedly reduced the fluorescence intensity of Gram-positive Staphylococcus aureus-conjugated Alexa 594 and Gram-negative Escherichia coli-conjugated Alexa 488. Interestingly, co-treatment with ethanol impaired the EGCG-mediated fluorescence quenching of the G+ S. aureus, but not of the G- E. coli-conjugated Alexa Flour dyes. In light of the notion that Alexa Fluor dyes can be quenched by aromatic amino acids, it is plausible that EGCG exerts antimicrobial activities possibly by altering microbial protein conformations and functions. This possibility can now be explored by screening other fluorescence-quenching agents for possible antimicrobial activities.

Interleukin-6 is a multifunctional cytokine that has been shown to be increased in some pathological conditions involving the respiratory system such as those experimentally induced in animals or spontaneously occurring in humans. Experimental data demonstrating that interleukin-6 plays a significant role in commonly occurring respiratory system inflammatory diseases are reviewed here. Those diseases, i.e. asthma and chronic obstructive pulmonary disease, are characterised by mechanical derangements of the respiratory system, for the most part due to increased elastance and airway resistance. Recent findings showing that interleukin-6 has a causative role in determining an increase in airway resistance are reviewed. The end-inflation occlusion method was used to study the mechanical properties of the respiratory system before and after interleukin-6 administration. The cytokine was shown to induce significant, dose-dependent increments in both the resistive pressure dissipation due to frictional forces opposing the airflow in the airway (ohmic resistance) and the additional resistive pressure dissipation due to the visco-elastic properties of the system, i.e. stress relaxation (visco-elastic resistance). There were no alterations in respiratory system elastance. Even when administered to healthy mammals, interleukin-6 determines a significant effect on respiratory system resistance causing an increase in the mechanical work of breathing during inspiration. IL-6 hypothetically plays an active role in the pathogenesis of respiratory system diseases and the mechanisms that may be involved are discussed here.

Introduction: The cardiovascular magnetic resonance (CMR) pattern of Churg-Strauss syndrome (CSS) includes myopericarditis, diffuse subendocardial vasculitis or myocardial infarction with or without cardiac symptoms and is usually associated with lack of antineutrophil cytoplasmic antibodies (ANCA). Aim: To correlate the CMR pattern with ANCA in CSS, compare it with healthy controls and systemic lupus erythematosus (SLE) patients and re-evaluate 2 yrs after the first CMR. Patients-Methods: 28 consecutive CSS, aged 42±7 yrs, were referred for CMR and 2 yrs re-evaluation. The CMR included left ventricular ejection fraction (LVEF), T2-weighted (T2-W), early (EGE) and late gadolinium enhanced (LGE) imaging. Their results were compared with 28 systemic lupus erythematosus (SLE) under remission and 28 controls with normal myocardial perfusion, assessed by scintigraphy. Results: CMR revealed acute cardiac lesions in all ANCA (-) CSS with active disease and acute cardiac symptoms and only in one asymptomatic ANCA (+) CSS, with active disease. Diffuse subendocardial fibrosis (DSF) or past myocarditis was identified in both ANCA(+) and ANCA (-) CSS, but with higher incidence and fibrosis amount in ANCA (-) CSS (p<0.05). In comparison to SLE, both ANCA (+) and ANCA (-) CSS had higher incidence of DSF, lower incidence of myocarditis and no evidence of myocardial infarction, due to coronary artery disease (p<0.05). In 2 yrs CMR follow up, 1/3 of CSS with DSF presented LV function deterioration and one died, although immunosuppressive treatment was given early after CSS diagnosis. Conclusions: Cardiac involvement either as DSF or myocarditis, can be detected in both ANCA (+) and ANCA (-) CSS, although more clinically overt in ANCA (-). DSF carries an ominous prognosis for LV function. CMR, due to its capability to detect disease severity, before cardiac dysfunction takes place, is an excellent tool for CSS risk stratification and treatment individualization.

Novel carrier-linked azo prodrugs of 4 and 5-aminosalicylic acids (4-ASA and 5-ASA respectively) using the same drugs as carriers in different permutations and combinations were designed for targeting colon affected with inflammatory bowel disease (IBD). Improved hydrophilic nature of the prodrugs assisted in minimizing their absorption in upper GIT and efficient delivery of the active drugs to colon as evidenced from their stability in aqueous buffers (pH 1.2 and 7.4) and upper GIT homogenates with 68-91% release on incubation with rat cecal matter. Amongst the series, 4A4AAZ (prodrug of 4-ASA with 4-ASA) at a dose of 53 mg/Kg was found to be the most promising candidate as it substantially alleviated the quantifying markers of colonic inflammation in TNBS-induced experimental colitis in Wistar rats. Moreover it displayed significantly lower GI toxicity (at ten times higher dose). 5-ASA- induced pancreatitis and sulfapyridine-induced adverse effects on liver that are characteristic of sulfasalazine were not observed with 4A4AAZ. It could be explored further as a potential candidate for IBD patients intolerant to pancreatitis induced by oral administration of 5-ASA.

Inflammation is viewed as one of the major causes for the development of different diseases like cancer, cardiovascular disease, diabetes, obesity, osteoporosis, rheumatoid arthritis, inflammatory bowel disease, asthma, and CNS related diseases such as depression and parkinson’s disease; and this fervent phenomenon provides space for understanding different inflammatory markers. Increasing evidences have elucidated the outcome of inflammatory pathways dysregulation resulting in many symptoms of chronic diseases. The detection of transcription factors such as nuclear factor kappa-B (NF-κB), STAT and their gene products such as COX-2, cytokines, chemokines and chemokine receptors has laid molecular foundation for the important role of inflammation in chronic diseases in which the NF-κB is reported as a major mediator which makes a possible way for the development of new therapeutic approaches using synthetic and natural compounds that might eventually decrease the prevalence of these diseases. Even if many inflammatory markers like TNF-α, IL-1, IL-6, IL-8 and C-reactive protein (CRP) are reported to be the major key factors with proved role in several inflammatory diseases, IL-1 and TNF-α are the important cytokines that can induce the expression of NF-κB which is the potential target in these inflammatory diseases. This review aims to explore and summarize that how some drugs and natural compounds show their modulatory activity in inflammatory pathways and chronic inflammatory markers in these inflammatory diseases.

The association between autoimmune rheumatic diseases and obstructive sleep apnea (OSA) is complex. Systemic inflammation secondary to OSA may underlie this association. It is possible that OSA-related inflammation may trigger the occurrence of autoimmune rheumatic disease in genetically susceptible individuals. On the other hand, autoimmune rheumatic diseases can lead to OSA or worsen preexisting OSA. Temporomandibular joint destruction, cervical spine subluxation and brainstem compression are the factors responsible for the above observation. Future studies are needed to clarify whether OSA is an independent risk factor for the development of autoimmune disease and whether OSA management will lead to a reduction in the incidence of autoimmune disease. On the other hand, it is important to treat autoimmune rheumatic disease promptly, to reduce the risk of complications, with OSA being one of these.