The effectiveness of Reslizumab in severe asthma treatment: a real-world experience.

BACKGROUND: Increased numbers of blood and sputum eosinophils are associated with higher exacerbation frequency and increased asthma severity. In clinical trials, targeting Interleukin-5 has been shown to be a useful therapeutic strategy for patients with severe eosinophilic asthma. METHODS: Twenty-six patients have been commenced on Reslizumab in our institution since early 2017. Safety and clinical efficacy parameters were recorded at regular intervals. RESULTS: Mean ACQ-6 score at the start of treatment was 3.5. The average number of exacerbations in the year preceding treatment was 8.3 per person. 30% of patients had been admitted to hospital at least once over the 12 months preceding therapy. 54% of our patients were on long term oral steroid. Our data showed sustained improvement of Asthma control (Mean improvement in ACQ-6 was 1.7 at 1 year, and 2.0 at 2 years, P = 0.0001). Of the patients who were on long term systemic steroids, 35.7% discontinued steroids completely, with a mean reduction of prednisolone dose of 5.2 mg at 1 year. There was a 79% reduction in the annual exacerbation frequency at 1 year, and 88% at 2 years (P = < 0.0001). Modest, albeit statistically significant increases in creatine kinase which seemed to plateau by 1 year were noted. CONCLUSIONS: Overall, Reslizumab was well tolerated with discontinuation of treatment due to side effects recorded in only one patient. Our data confirm the utility of anti-IL5 therapy in a carefully selected phenotype of severe asthma with evidence of eosinophilic airway inflammation.

Gastric Aspiration and Its Role in Airway Inflammation.

Gastro-Oesophageal Reflux (GOR) has been associated with chronic airway diseases while the passage of foreign matter into airways and lungs through aspiration has the potential to initiate a wide spectrum of pulmonary disorders. The clinical syndrome resulting from such aspiration will depend both on the quantity and nature of the aspirate as well as the individual host response. Aspiration of gastric fluids may cause damage to airway epithelium, not only because acidity is toxic to bronchial epithelial cells but also due to the effect of digestive enzymes such as pepsin and bile salts. Experimental models have shown that direct instillation of these factors to airways epithelia cause damage with a consequential inflammatory response. The pathophysiology of these responses is gradually being dissected, with better understanding of acute gastric aspiration injury, a major cause of acute lung injury, providing opportunities for therapeutic intervention and potentially, ultimately, improved understanding of the chronic airway response to aspiration. Ultimately, clarification of the inflammatory pathways which are related to micro-aspiration via pepsin and bile acid salts may eventually progress to pharmacological intervention and surgical studies to assess the clinical benefits of such therapies in driving symptom improvement or reducing disease progression.

The influence of rosuvastatin on the gastrointestinal microbiota and host gene expression profiles.

Statins are the most widely prescribed medications worldwide for the treatment of hypercholesterolemia. They inhibit the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-R), an enzyme involved in cholesterol synthesis in higher organisms and in isoprenoid biosynthesis in some bacteria. We hypothesized that statins may influence the microbial community in the gut through either direct inhibition or indirect mechanisms involving alterations to host responses. We therefore examined the impact of rosuvastatin (RSV) on the community structure of the murine gastrointestinal microbiota. RSV was orally administered to mice and the effects on the gut microbiota, host bile acid profiles, and markers of inflammation were analyzed. RSV significantly influenced the microbial community in both the cecum and feces, causing a significant decrease in α-diversity in the cecum and resulting in a reduction of several physiologically relevant bacterial groups. RSV treatment of mice significantly affected bile acid metabolism and impacted expression of inflammatory markers known to influence microbial community structure (including RegIIIγ and Camp) in the gut. This study suggests that a commonly used statin (RSV) leads to an altered gut microbial composition in normal mice with attendant impacts on local gene expression profiles, a finding that should prompt further studies to investigate the implications of statins for gut microbiota stability and health in humans.NEW & NOTEWORTHY This work demonstrates that rosuvastatin administration in mice affects the gastrointestinal microbiota, influences bile acid metabolism, and alters transcription of genes encoding factors involved in gut homeostasis and immunity in the gastrointestinal tract.

Differential expression of key regulators of Toll-like receptors in ulcerative colitis and Crohn's disease: a role for Tollip and peroxisome proliferator-activated receptor gamma?

The innate immune system is currently seen as the probable initiator of events which culminate in the development of inflammatory bowel disease (IBD) with Toll-like receptors (TLRs) known to be involved in this disease process. Many regulators of TLRs have been described, and dysregulation of these may also be important in the pathogenesis of IBD. The aim of this study was to perform a co-ordinated analysis of the expression levels of both key intestinal TLRs and their inhibitory proteins in the same IBD cohorts, both ulcerative colitis (UC) and Crohn's disease (CD), in order to evaluate the potential roles of these proteins in the pathogenesis of IBD. Of the six TLRs (TLRs 1, 2, 4, 5, 6 and 9) examined, only TLR-4 was increased significantly in IBD, specifically in active UC. In contrast, differential alterations in expression of TLR inhibitory proteins were observed. A20 and suppressor of cytokine signalling 1 (SOCS1) were increased only in active UC while interleukin-1 receptor-associated kinase 1 (IRAK-m) and B cell lymphoma 3 protein (Bcl-3) were increased in both active UC and CD. In contrast, expression of both peroxisome proliferator-activated receptor gamma (PPARγ) and Toll interacting protein (Tollip) was decreased in both active and inactive UC and CD and at both mRNA and protein levels. In addition, expression of both PPARγ and A20 expression was increased by stimulation of a colonic epithelial cell line Caco-2 with both TLR ligands and commensal bacterial strains. These data suggest that IBD may be associated with distinctive changes in TLR-4 and TLR inhibitory proteins, implying that alterations in these may contribute to the pathogenesis of IBD.

Bifidobacterium infantis suppression of Peyer's patch MIP-1α and MIP-1ß secretion during Salmonella infection correlates with increased local CD4+CD25+ T cell numbers.

The outcome following infection depends on the generation of an immune response that results in control of the pathogenic microorganism, while limiting inflammatory collateral damage to the host. Bifidobacterium infantis 35624 was shown to be protective against Salmonella associated host injury via a Treg-dependent mechanism. In this study, we further examined the mechanisms by which B. infantis-induced Tregs protect against Salmonella-associated inflammation. B. infantis 35624 feeding to Salmonella-infected mice significantly reduced Peyer's patch MIP-1α and MIP-1ß secretion. Chemokine secretion was significantly inversely correlated with Peyer's patch CD4+CD25+ cell numbers. In vitro, CD25+ T cells, but not CD25- T cells, specifically inhibited TNF-α and IFN-γ secretion. However, both CD25+ and CD25- T cells suppressed MIP-1α and MIP-1ß secretion to the same extent. This study suggests that although B. infantis 35624-induced Tregs correlate with inhibition of chemokine secretion within the mucosa of pathogen infected animals, indirect cellular mechanisms may play a role.

Bacterial strain-specific induction of Foxp3+ T regulatory cells is protective in murine allergy models.

BACKGROUND: The incidence of atopic disease has increased dramatically during recent decades and the potential immunoregulatory influence of the microbiota in these individuals is under investigation. OBJECTIVE: The aim of our study was to identify a bacterial strain that is protective in murine allergy models and to determine if microbial induction of T regulatory cells was associated with protection from allergic inflammation. METHODS: Three microbes (Bifidobacterium breve AH1205, B. longum AH1206 and Lactobacillus salivarius AH102) of human origin were fed to newborn, adult and germ-free animals. Induction of Foxp3(+) T regulatory cells was assessed by flow cytometry. Gene array analysis was performed on Peyer's patches. Strains were also examined for their protective effects in the ovalbumin (OVA) respiratory allergy model and the OVA-cholera toxin dietary allergy model. RESULTS: Bifidobacterium longum AH1206 consumption resulted in increased numbers of Foxp3(+) T regulatory cells in infant, adult and germ-free animals. B. breve AH1205 induced Foxp3(+) T regulatory cell expansion only in infant mice while L. salivarius AH102 did not alter T regulatory cell numbers in any animal model tested. B. longum AH1206 reduced the Peyer's patch gene expression associated with antigen presentation, TLR signalling and cytokine production while increasing the expression of genes associated with retinoic acid metabolism. B. longum AH1206 protected against airway inflammation in OVA-sensitized animals and B. longum AH1206 blocked the induction of IgE to orally administered OVA. Neither B. breve AH1205 nor L. salivarius AH102 had a protective effect in either model. CONCLUSION: Bacterial strain-specific induction of Foxp3(+) T regulatory cells in vivo is associated with protection from respiratory and oral allergy.

Asymptomatic carriage of Clostridium difficile in an Irish continuing care institution for the elderly: prevalence and characteristics.

INTRODUCTION: Clostridium difficile is an increasing cause of nosocomial diarrhoea and colitis. The aim of this study was to identify the prevalence and characteristics of asymptomatic C. difficile carriage in a continuing care institution for the elderly. METHODS: Stool samples were collected from 100 asymptomatic patients, whose median age was 83 years. Samples were tested for C. difficile using traditional culturing methods, 16s rDNA and 16s-23s intergenic spacer (IGS) rDNA sequencing, and analysed for toxin production and toxin genes. RESULTS: The prevalence of C. difficile carriage was 10/100 (10%) following culture and 16s and IGS sequencing. An additional seven isolates, initially identified as C. difficile, were subsequently identified by IGS rDNA sequencing as C. sordellii of the 10% that tested positive for C. difficile, seven tested positive for toxin A and B. A significant number of C. difficile carriers had recent antibiotic exposure compared with non-carriers, P = 0.046. CONCLUSION: The prevalence of asymptomatic C. difficile carriage in this institution was 10%, 7% of which were toxin positive. This study underscores the importance of increased vigilance for C. difficile using microbial and molecular methodology and identifies patients at increased risk following antibiotic administration.

Portrait of a canine probiotic Bifidobacterium--from gut to gut.

The gastrointestinal environment is a complex interactive system involving the host, ingested dietary components, and numerous microbial species. We hypothesized that isolation and screening of Lactobacilli and Bifidobacteria adherent to healthy canine gastrointestinal tissue would yield strains with commensal activity in canines. The aims of this study were (1) to isolate a bank of commensal organisms from the canine gastrointestinal tract; (2) to screen these novel microbial isolates for potential probiotic effects; (3) to select one organism from these screens and test its impact on the canine microbiota. Lactic acid bacteria (LAB) were isolated from resected canine gastrointestinal tissue and screened in vitro for putative probiotic activities. Murine studies examined gastrointestinal transit and inhibition of Salmonella typhimurium translocation. One strain was progressed to a canine study where its impact on the gastrointestinal microbiota was determined. Of the 420 isolates from the canine gut, 62 strains were characterised as LAB. Following assessment of the strain bank with regard to pH sensitivity, bile resistance, pathogen inhibition and survival following freeze-drying, four Lactobacillus strains and two Bifidobacteria strains were selected for further examination. Bifidobacterium animalis AHC7 adhered to epithelial cells, transited the murine gastrointestinal tract to high numbers and significantly reduced S. typhimurium translocation. B. animalis AHC7 consumption significantly reduced the carriage of Clostridia, in particular Clostridium difficile, in dogs. This study describes the isolation and screening of canine-derived bacterial strains with commensal traits. The results demonstrate that B. animalis AHC7 has significant potential for improving canine gastrointestinal health.

Role of interleukin (IL-10) in probiotic-mediated immune modulation: an assessment in wild-type and IL-10 knock-out mice.

While the impact of Bifidobacterium infantis 35624 and other probiotics on cytokines has been shown in established colitis, the effects of B. infantis consumption in pre-inflammation of interleukin (IL)-10 knock-out (KO) mice and on the wild-type (WT) C57Bl/6 mice have not been well demonstrated. The objective of this study was to examine cytokine responses in mucosal and systemic lymphoid compartments of IL-10 KO mice early in disease and to compare with control WT mice. Mice were fed B. infantis or placebo for 5 weeks and culled prior to the onset of chronic intestinal inflammation (12-14 weeks). The spleen, Peyer's patches and intestinal mucosa were removed and stimulated with various bacterial stimuli. Cytokine levels were measured by enzyme-linked immunosorbent assay. While basal intestinal and systemic cytokine profiles of WT and IL-10 KO mice were similar, transforming growth factor (TGF)-beta was reduced in the spleen of IL-10 KO mice. Following probiotic consumption, interferon (IFN)-gamma was reduced in the Peyer's patch of both WT and IL-10 KO mice. Alterations in IFN-gamma in the Peyer's patches of WT mice (enhancement) versus IL-10 KO (reduction) were observed following in vitro stimulation with salmonella. Differential IL-12p40, CCL2 and CCL5 responses were also observed in IL-10 KO mice and WT mice. The cytokine profile of IL-10 KO mice in early disease was similar to that of WT mice. The most pronounced changes occurred in the Peyer's patch of IL-10 KO mice, suggesting a probiotic mechanism of action independent of IL-10. This study provides a rationale for the use of B. infantis 35624 for the treatment of gastrointestinal inflammation.