Overcoming Barriers to Health and Wellbeing : Community Assets in North East Essex

The Overcoming Barriers to Health and Wellbeing report presents research carried out by Public Health and Social Science researchers at Anglia Ruskin University. Colchester Borough Council commissioned this independent study with funding from the North East Essex Health and Wellbeing Alliance. The aim of the research is to provide Local Authorities and health and wellbeing commissioners with insight into the public health benefits of community assets from the perspective of citizens who access them in their local communities. This report provides an evidence-based rationale for the support of community assets to improve the health and wellbeing outcomes of citizens in North East Essex. There is a focus on populations considered to be at increased risk of poor health and wellbeing outcomes, and on addressing populations in places where there are areas of comparative social deprivation in the context of growing health inequalities in the region

Distinct phenotypes of platelet, monocyte, and neutrophil activation occur during the acute and convalescent phase of COVID-19

SARS-CoV-2 has spread rapidly worldwide, causing the COVID-19 pandemic. Platelet activation and platelet-leukocyte complex formation are proposed to contribute to disease progression. Here, we report platelet and leukocyte activation during acute and convalescent COVID-19 in patients recruited between May-July 2020. Blood samples were analyzed by flow cytometry and ELISA using paired comparison between inclusion (day 0) and 28 days later. The majority of patients were mildly or moderately ill with significantly higher cytokine levels (IL-6 and IL-10) on day 0 as compared with day 28. Platelet activation and granule release were significantly higher on day 0 compared with day 28, as determined by ADP- or thrombin-induced surface CD62P expression, baseline released CD62P, and thrombin-induced platelet-monocyte complex formation. Monocyte activation and procoagulant status at baseline and post activation were heterogeneous but generally lower on day 0 compared with day 28. Baseline and thrombin- or fMLF-induced neutrophil activation and procoagulant status were significantly lower on day 0 compared with day 28. We demonstrate that during the acute phase of COVID-19 compared with the convalescent phase, platelets are more responsive while neutrophils are less responsive. COVID-19 is associated with thromboembolic events where platelet activation and interaction with leukocytes may play an important role

IdeS: A Bacterial Proteolytic Enzyme with Therapeutic Potential

Background: IdeS, a proteinase from Streptococcus pyogenes, cleaves immunoglobulin (Ig)G antibodies with a unique degree of specificity. Pathogenic IgG antibodies constitute an important clinical problem contributing to the pathogenesis of a number of autoimmune conditions and acute transplant rejection. To be able to effectively remove such antibodies is therefore an important clinical challenge. Methodology/Principal Findings: IdeS was found to specifically and efficiently cleave IgG in human blood in vitro (20 mg of IdeS caused a complete degradation of IgG in one ml of human whole blood in 15 minutes) and to clear IgG from the blood stream of rabbits in vivo (no IgG was detected six hours following an intravenous injection of 5 mg of IdeS) without any side effects. In a mouse model of immune thrombocytopenic purpura (ITP), polyclonal IgG antibodies against platelet surface antigens were used to induce a lethal disease. These profoundly thrombocytopenic animals were treated and cured by a single injection of IdeS. Conclusions/Significance: Novel information is provided concerning the IgG-cleaving activity of IdeS in vitro and in vivo. The highly specific and rapid elimination of IgG in vivo, the dramatic effect in a mouse model of ITP, and the lack of sid

Protein C Inhibitor—A Novel Antimicrobial Agent

Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which subsequently leads to their permeabilization. As shown by negative staining electron microscopy, treatment of Escherichia coli or Streptococcus pyogenes bacteria with PCI triggers membrane disruption followed by the efflux of bacterial cytosolic contents and bacterial killing. The antimicrobial activity of PCI is located to the heparin-binding site of the protein and a peptide spanning this region was found to mimic the antimicrobial activity of PCI, without causing lysis or membrane destruction of eukaryotic cells. Finally, we show that platelets can assemble PCI on their surface upon activation. As platelets are recruited to the site of a bacterial infection, these results may explain our finding that PCI levels are increased in tissue biopsies from patients suffering from necrotizing fasciitis caused by S. pyogenes. Taken together, our data describe a new function for PCI in innate immunity

Platelet and Neutrophil Responses to Gram Positive Pathogens in Patients with Bacteremic Infection

BACKGROUND: Many Gram-positive pathogens aggregate and activate platelets in vitro and this has been proposed to contribute to virulence. Platelets can also form complexes with neutrophils but little is however known about platelet and platelet-neutrophil responses in bacterial infection. METHODOLOGY/PRINCIPAL FINDINGS: We added isolates of Gram-positive bacteria from 38 patients with a bacteremic infection to blood drawn from the same patient. Aggregometry and flow cytometry were used to assess platelet aggregation and to quantify activation of platelets, neutrophils, and platelet-neutrophils complexes (PNCs) induced by the bacteria. Fifteen healthy persons served as controls. Most isolates of Staphylococcus aureus, beta hemolytic streptococci, and Enterococcus faecalis induced aggregation of platelets from their respective hosts, whereas pneumococci failed to do so. S. aureus isolates induced platelet aggregation more rapidly in patients than in controls, whereas platelet activation by S. aureus was lower in patients than in controls. PNCs were more abundant in baseline samples from patients than in healthy controls and most bacterial isolates induced additional PNC formation and neutrophil activation. CONCLUSION/SIGNIFICANCE: We have demonstrated for the first time that bacteria isolated from patients with Gram-positive bacteremia can induce platelet activation and aggregation, PNC formation, and neutrophil activation in the same infected host. This underlines the significance of these interactions during infection, which could be a target for future therapies in sepsis

Antibodies against a Surface Protein of Streptococcus pyogenes Promote a Pathological Inflammatory Response

Streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes is a clinical condition with a high mortality rate despite modern intensive care. A key feature of STSS is excessive plasma leakage leading to hypovolemic hypotension, disturbed microcirculation and multiorgan failure. Previous work has identified a virulence mechanism in STSS where M1 protein of S. pyogenes forms complexes with fibrinogen that activate neutrophils to release heparin-binding protein (HBP), an inducer of vascular leakage. Here, we report a marked inter-individual difference in the response to M1 protein–induced HBP release, a difference found to be related to IgG antibodies directed against the central region of the M1 protein. To elicit massive HBP release, such antibodies need to be part of the M1 protein–fibrinogen complexes. The data add a novel aspect to bacterial pathogenesis where antibodies contribute to the severity of disease by promoting a pathologic inflammatory response

Determining platelet activation and aggregation in response to bacteria

Many pathogenic bacteria have been reported to interact with human platelets to mediate platelet activation and aggregation. The importance of these interactions to the immune response or pathogenesis of bacterial infection has not been clarified. It may therefore be valuable to assess platelet responses mediated by diverse strains of bacteria. Here, I describe a method to study platelet integrin activation and granule release using flow cytometry, and a complementary method to study platelet aggregation using a dedicated platelet aggregometer. The combination of these methods represents a rapid and cost-effective strategy to provide mechanistic insight on the type of platelet response mediated by the bacteria

Biological effects of extracellular fibrinogen binding protein (Efb) in staphylococcus aureus infection

Staphylococcus aureus is a leading cause of human and animal infection. The increasing incidence of antibiotic resistance among strains has complicated treatment of these infections. In order to develop new treatment strategies, it is important to identify and characterise bacterial factors that contribute to infection. S. aureus produces a diverse array of virulence factors, among these Extracellular fibrinogen binding protein, Efb. Efb is one of several fibrinogen-binding proteins produced by S. aureus. Efb is produced in vivo during infection and contributes to the pathogenesis of severe S. aureus wound infection in an animal model. This thesis has been focussed on characterising the biological function of Efb in S. aureus infection. We have shown that Efb interacts with the Aalpha chain of fibrinogen, at a site of functional importance for the interaction between fibrinogen and platelets. We have studied the effect of Efb on platelet function in vitro and in vivo. Efb bound specifically to a receptor on activated platelets, however fibrinogen was not involved in mediating this binding. Efb stimulated a novel type of fibrinogen binding to the platelet, which did not involve the normal platelet fibrinogen receptor, GPIIb/IIIa. We propose that fibrinogen can also bind to the platelet via Efb and this generates the novel fibrinogen binding mediated by Efb. In the presence of Efb, platelet activation was diminished and Efb also inhibited platelet aggregation in response to various platelet agonists. This antiplatelet effect of Efb was confirmed in vivo. Intravenous Efb significantly prolonged bleeding time but had no effect on the coagulation system. This confirms that Efb specifically inhibits platelet function. Moreover, in a mouse model, intravenous Efb rescued 100% of animals from death due to acute thrombosis. This reflects the inability of the platelets to aggregate in the presence of Efb, an effect so powerful that Efb can counteract the massive thrombosis generated in this model. We have also studied the immune response against Efb and characterised a protective antibody response. Hyperimmune IgG against Efb neutralised Efb and blocked the various biological effects of Efb in vitro. IgG against Efb blocked Efb binding to fibrinogen, neutralised Efb and returned platelet aggregation in the presence of Efb to normal. Furthermore, immunization with Efb protected against the development of severe infection in an animal model of S. aureus infection. The animals in the vaccinated group developed high titre, specific antibodies against Efb and had significantly less severe infection than those in the unvaccinated group. This establishes Efb as a worthy vaccine candidate for S. aureus infection. Collectively, in this thesis we have elucidated the biological function of Efb and confirmed its importance in S. aureus wound infection. Efb is a powerful antiplatelet agent, which impairs haemostasis and wound healing. Efb also represents a worthwhile vaccine candidate for certain S. aureus infections