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BackgroundHaemostasis is a crucial process by which the body stops bleeding. It is achieved by the formation of a platelet plug, which is strengthened by formation of a fibrin mesh mediated by the coagulation cascade. In proinflammatory and prothrombotic conditions, multiple interactions of the complement system and the coagulation cascade are known to aggravate thromboinflammatory processes and increase the risk of arterial and venous thrombosis. Whether those interactions also play a relevant role during the physiological process of haemostasis is not yet completely understood. The aim of this study was to investigate the potential role of complement components and activation during the haemostatic response to mechanical vessel injury.MethodsWe used a microvascular bleeding model that simulates a blood vessel, featuring human endothelial cells, perfusion with fresh human whole blood, and an inducible mechanical injury to the vessel. We studied the effects of complement inhibitors against components of the lectin (MASP-1, MASP-2), classical (C1s), alternative (FD) and common pathways (C3, C5), as well as a novel triple fusion inhibitor of all three complement pathways (TriFu). Effects on clot formation were analysed by recording of fibrin deposition and the platelet activation marker CD62P at the injury site in real time using a confocal microscope.ResultsWith the inhibitors targeting MASP-2 or C1s, no significant reduction of fibrin formation was observed, while platelet activation was significantly reduced in the presence of the FD inhibitor. Both common pathway inhibitors targeting C3 or C5, respectively, were associated with a substantial reduction of fibrin formation, and platelet activation was also reduced in the presence of the C3 inhibitor. Triple inhibition of all three activation pathways at the C3-convertase level by TriFu reduced both fibrin formation and platelet activation. When several complement inhibitors were directly compared in two individual donors, TriFu and the inhibitors of MASP-1 and C3 had the strongest effects on clot formation.ConclusionThe observed impact of complement inhibition on reducing fibrin clot formation and platelet activation suggests a role of the complement system in haemostasis, with modulators of complement initiation, amplification or effector functions showing distinct profiles. While the interactions between complement and coagulation might have evolved to support haemostasis and protect against bleeding in case of vessel injury, they can turn harmful in pathological conditions when aggravating thromboinflammation and promoting thrombosis.

Many viral antigens have been identified in patients with COVID-19 patients, but which of these result in meaningful immune responses is unclear. Here the authors identify a range of SARS-CoV-2 CD8+ T cell responses across patients including a response targeting an epitope of ORF1ab with immunodominant properties.

The logistics and transport industry is currently facing the major challenge of having a global shortage of skilled workers. To address this challenge, this paper evaluates the application of gamification in combination with augmented reality (AR) as a new approach to attract the interest of people of all ages to the logistics sector. The aim of the paper is to determine whether a gamified AR-based application called Logistify is a feasible approach to make logistics jobs more attractive. We used a qualitative approach in three phases by collecting and analysing data from different perspectives of players, teachers, instructors, and programmers about the application: (1) analysing game characteristics with programmers and workshops instructors, (2) collecting feedback from players and teachers, and (3) evaluating game scores. The evaluation shows that gamification in combination with augmented reality is a promising tool to attract people to the logistics sector and to change their perception of logistics professions. It can be concluded that the gamified AR approach is capable of increasing interest in jobs in a particular sector.

In a knowledge society knowledge is dynamic, distributed and dependent on social context. The variety of professional communities of practice (CoP) and their individual knowledge needs are a challenge for community information systems for learning and knowledge exchange. Social Micro-Learning is an approach that allows the co-creation of new individualized knowledge artifact types for specific needs of a certain CoP. In this paper we propose a co-creation approach for Social Micro-Learning and evaluate it in workshops with four different CoPs in the professional domain. Our results confirm our assumptions about the diversity of knowledge needs and show that our co-creation process is highly appreciated.

Some studies suggest that eating more than one egg daily may increase risk of death from cardiovascular disease. The objective of this study was to determine the effects of consuming eggs on various serum markers associated with cardiovascular disease (CVD). Forty-five independently living adults diagnosed with early macular degeneration, but healthy otherwise were recruited into the study. Subjects were placed into the Intervention (n = 27) or Control group (n = 18) based on whether or not they would consume eggs. The Intervention group consumed 12 eggs per week while the Control group refrained from consuming any whole egg products for 1 year. Serum concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glucose, apolipoprotein (apo) A-1 and apo B, lipoprotein (Lp)a and high-sensitive C reactive protein (hsCRP) were measured at baseline, 6, and 12 months. Serum low-density lipoprotein cholesterol (LDL-C) concentration was calculated via the Friedewald equation. Serum TC, TG, HDL-C, LDL-C, apo A-1, apo B, Lpa and hsCRP concentrations did not change at any time in both the Intervention and Control groups compared to baseline nor were there any differences between the two treatment. Serum glucose concentrations did increase significantly in the Intervention group at 6 months compared to baseline (23%, P

To discriminate between self and non-self surfaces and facilitate immune surveillance, the complement system relies on the interplay between surface-directed activators and regulators. The dimeric modulator FHR-1 is hypothesized to competitively remove the complement regulator FH from surfaces that strongly fix opsonic C3b molecules—a process known as “deregulation.” The C-terminal regions of FH and FHR-1 provide the basis of this competition. They contain binding sites for C3b and host surface markers and are identical except for two substitutions: S1191L and V1197A (i.e., FH “SV”; FHR-1 “LA”). Intriguingly, an FHR-1 variant featuring the “SV” combination of FH predisposes to atypical hemolytic uremic syndrome (aHUS). The functional impact of these mutations on complement (de)regulation, and their pathophysiological consequences, have largely remained elusive. We have addressed these questions using recombinantly expressed wildtype, mutated, and truncated versions of FHR-1 and FH. The “SV” to “LA” substitutions did not affect glycosaminoglycan recognition and had only a small effect on C3b binding. In contrast, the two amino acids substantially affected the binding of FH and FHR-1 to α2,3-linked sialic acids as host surfaces markers, with the S-to-L substitution causing an almost complete loss of recognition. Even with sialic acid-binding constructs, notable deregulation was only detected on host and not foreign cells. The aHUS-associated “SV” mutation converts FHR-1 into a sialic acid binder which, supported by its dimeric nature, enables excessive FH deregulation and, thus, complement activation on host surfaces. While we also observed inhibitory activities of FHR-1 on C3 and C5 convertases, the high concentrations required render the physiological impact uncertain. In conclusion, the SV-to-LA substitution in the C-terminal regions of FH and FHR-1 diminishes its sialic acid-binding ability and results in an FHR-1 molecule that only moderately deregulates FH. Such FH deregulation by FHR-1 only occurs on host/host-like surfaces that recruit FH. Conversion of FHR-1 into a sialic acid binder potentiates the deregulatory capacity of FHR-1 and thus explains the pathophysiology of the aHUS-associated FHR-1 “SV” variant.

Factor H (FH), a member of the regulators-of-complement-activation (RCA) family of proteins, circulates in human plasma at concentrations of 180–420 mg/L where it controls the alternative pathway (AP) of complement in the fluid phase and on cell surfaces. When the regulatory function of FH is impaired, complement-mediated tissue injury and inflammation occur, leading to diseases such as atypical hemolytic uremic syndrome (a thrombotic microangiopathy or TMA), C3 glomerulopathy (C3G) and monoclonal gammopathy of renal significance (MGRS). A pathophysiological cause of compromised FH function is the development of autoantibodies to various domains of the FH protein. FH autoantibodies (FHAAs) are identified in 10.9% of patients with aHUS, 3.2% of patients with C3G, and rarely in patients with MGRS. The phenotypic variability of FHAA-mediated disease reflects both the complexity of FH and the epitope specificity of FHAA for select regions of the native protein. In this paper, we have characterized FHAA epitopes in a large cohort of patients diagnosed with TMA, C3G or MGRS. We explore the epitopes recognized by FHAAs in these diseases and the association of FHAAs with the genetic deletion of both copies of the CFHR1 gene to show how these disease phenotypes are associated with this diverse spectrum of autoantibodies.

The alternative pathway regulator Factor H-like protein 1 (FHL-1) is composed of the first 7 N-terminal complement control protein domains of Factor H (FH) and protects host surfaces from uncontrolled complement attack. Although FHL-1 shares the N-terminal regulatory domains with FH, it was thought to be a weaker regulator. Recently, the regulatory activity of FHL-1 was shown to be comparable to FH. Nonetheless, the question remained whether FHL-1 is an indispensable, unique regulator. The discovery that FHL-1 is the predominant regulator on Bruch’s membrane, a critical site for the onset and progression of age-related-macular degeneration (AMD), showed that FHL-1 is essential for complement regulation. A common single nucleotide polymorphism in FH/FHL-1 that predisposes for AMD underlines the important role of FHL-1 in this context. Reports that some cancer tissues specifically upregulate FHL-1 expression, thereby evading immune surveillance, suggests a pronounced regulatory activity of the splice variant. Several microorganisms specifically recruit FHL-1 to evade complement attack. From a phylogenetic point of view, FHL-1 appears much later than other complement regulators, which could imply a specific role that is possibly not systemic but rather tissue specific. This review focuses on the current knowledge of FHL-1 and its physiological and pathophysiological roles.

ObjectiveThe purpose of this study was to determine the prevalence of components of the metabolic syndrome in adolescents with spinal cord injury (SCI) and spina bifida (SB), and their associations with obesity in subjects with and without SCI and SB.MethodsFifty-four subjects (20 SCI and 34 SB) age 11 to 20 years with mobility impairments from lower extremity paraparesis were recruited from a hospital-based clinic. Sixty able-bodied subjects who were oversampled for obesity served as controls (CTRL). Subjects were categorized as obese if their percent trunk fat measured by dual x-ray absorptiometry (DXA) was > 30.0% for males and > 35.0% for females. Ten SCI, 24 SB, and 19 CTRL subjects were classified as obese. Fasting serum samples were collected to determine serum glucose, insulin, and lipid concentrations. Metabolic syndrome was defined as having > or =3 of the following components: (a) obesity; (b) high-density lipoprotein (HDL) or =95th percentile for age/ height/gender, and (e) insulin resistance determined by either fasting serum glucose 100-125 mg/dL; fasting insulin > or =20 microU /mL; or homeostasis model assessment of insulin resistance > or = 4.0.ResultsMetabolic syndrome was identified in 32.4% of the SB group and 55% of the SCI group. Metabolic syndrome occurred at a significantly higher frequency in obese subjects (SB = 45.8%, SCI = 100%, CTRL = 63.2%) than nonobese subjects (SB = 0%, SCI = 10%, CTRL = 2.4%).ConclusionsThe prevalence of metabolic syndrome in adolescents with SB/SCI is quite high, particularly in obese individuals. These findings have important implications due to the known risks of cardiovascular diseases and diabetes mellitus associated with metabolic syndrome in adults, particularly those with spinal cord dysfunction.

Background: Eculizumab blocks the lytic complement pathway by inhibiting C5 and has become the standard of care for certain complement-mediated diseases. Previously, we have shown that strong complement activation in vitro overrides the C5 inhibition by Eculizumab, which accounts for residual terminal pathway activity.Results: Here we show that the levels of residual hemolysis in ex vivo assays differ markedly (up to 3.4-fold) across sera collected from different paroxysmal nocturnal hemoglobinuria (PNH) patients on Eculizumab treatment. This large variability of residual activity was also found in sera of healthy donors, thus cross-validating the findings in patients. While PNH patients with residual lytic activities of 11–30% exhibited hemolysis levels around the upper limit of normal (i.e., plasma LDH of ~250 u/L), as expected for PNH patients on Eculizumab therapy, we found sustained and markedly increased LDH levels of around 400 u/L for the patient with the highest residual activity of 37%. Furthermore, the clinical history of nine out of 14 PNH patients showed intravascular breakthrough hemolysis at the time of documented infections despite ample amounts of administered Eculizumab and/or experimentally determined excess over C5.Conclusion: The occurrence of extraordinary high levels of residual terminal pathway activity in PNH patients receiving Eculizumab is rare, but can impair the suppression of hemolysis. The commonly observed low levels of residual terminal pathway activity seen for most PNH patients can exacerbate during severe infections and, thus, can cause pharmacodynamic breakthrough hemolysis in PNH patients treated with Eculizumab.