Activation Of Alternative Complement Pathway Research Articles

Complement activation by RPE cells preexposed to TNFα and IFNγ

Age-related macular degeneration (AMD) has been associated with both complement activation and increased levels of circulating cytokines. Here, we sougth to investigate if cytokine-preexposure of retinal pigment epithelial (RPE) leads to increased complement activation and deposition of membrane attack complex (MAC). Primary human RPE and the ARPE19 cell line cultured in serum-free conditions were preexposed to 100 ng/ml interferon-gamma (IFNγ) and 20 ng/ml tumor necrosis factor-alpha (TNFα) for 48 h followed by exposure to diluted serum from healthy donors or complement factor B deficient (CFBd) serum for 70 min. Deposition of membrane attack complexes (MAC) was examined by use of a MAC-ELISA kit and by immunofluorescence. Eculizumab (anti-C5) was examined for its ability to prevent deposition of MAC on RPE cells exposed to serum. Lactatdehydrogenase (LDH) and thiazolyl blue tetrazolium bromide (MTT) assays were used to assess cellular metabolism and survival. MAC was deposited only on RPE preexposed to both IFNγ and TNFα. Lack of complement factor B or inhibition of C5 abrogated the MAC-deposition on RPE cells, while reconstitution of CFBd serum with CFB resulted in MAC-deposition. MAC-deposition resulted in RPE-release of LDH, but unaltered mitochondrial activity estimated by MTT. We conclude that preexposure of primary RPE and ARPE19 with inflammatory cytokines promoted alternative pathway activation of complement and deposition of MAC. This implies that circulating inflammatory mediators may increase susceptibility to local complement activation and MAC-deposition, which may represent an early event in the pathogenesis leading to AMD development.

Lectin and alternative complement pathway activation in cutaneous manifestations of IgA-vasculitis: A new target for therapy?

IgA-vasculitis is a systemic small-vessel leucocytoclastic vasculitis and is associated with a high morbidity. The disease can progress to IgA-vasculitis with nephritis (IgAVN) which can result in chronic renal failure. Complement activation is involved in the pathogenesis of IgA-vasculitis. A recent study has shown that cutaneous C3c deposition in IgA-vasculitis is associated with a higher risk to develop IgAVN. In the current study we investigated the different complement pathways that are activated in cutaneous IgA-vasculitis in order to reveal potential targets for intervention. In addition, we analyzed the association of complement factors with IgAVN and the clinical course of the disease.In this retrospective study, the clinicopathological features of 17 patients with IgA-vasculitis were compared with 25 non-IgA-vasculitis cases. Deposition of immunoglobulins and complement was analyzed by direct immunofluorescence for IgA, IgG, IgM, C1q, C4d, properdin, mannan-binding lectin (MBL), ficolin-2 (FCN2), MBL-associated serine protease 1/3 (MASP1/3), MASP2 and C3c. The vascular intensity and positive area was scored on a nominal scale and cumulative score was calculated by multiplying the intensity x area.Properdin was positive in 82% of IgA-vasculitis cases, reflecting alternative pathway activation. C4d was positive in 88% of IgA-vasculitis cases reflecting classical and/or lectin pathway activation, although only 12% of cases were positive for C1q. Lectin pathway activation was demonstrated by deposition of MBL (47%), MASP1/3 (53%) and MASP2 (6%) while FCN2 was found negative. Significantly more deposition of MASP1/3 was found in IgA-vasculitis versus non-IgA-vasculitis.This study demonstrates for the first time activation of lectin and alternative pathways in cutaneous manifestations of IgA-vasculitis. Hence, drugs that intervene in these complement pathways may be an interesting more targeted alternative to the current drugs, in reducing local cutaneous symptoms of the disease, with potentially less side-effects. No association was found between complement activation and IgAVN and/or response to therapy. Therefore, it is unlikely that intervention in complement activation will lead to a better clinical course of the disease.

POS-546 EFFICACY AND SAFETY OF IPTACOPAN IN IgA NEPHROPATHY: RESULTS OF A RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROLLED PHASE 2 STUDY AT 6 MONTHS

No approved targeted therapies currently exist for IgA nephropathy (IgAN). Targeting the alternative complement pathway (AP) is an attractive therapeutic strategy given its role in the pathogenesis of IgAN. Iptacopan (LNP023) is a first-in-class, oral, potent and highly selective inhibitor of factor B of AP. This randomized, double-blind, dose-ranging, parallel-group adaptive design Phase 2 study (NCT03373461) enrolled patients with biopsy-confirmed IgAN (within the previous 3 years), urine protein-to-creatinine ratio (UPCR) ≥0.8 g/g or urine protein ≥0.75 g/24 h, and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2. Part 1 of the study enrolled patients for a 3-month treatment period; Part 2 of the study enrolled patients for a 6-month treatment period; both Parts comprised a 3-month treatment-free follow-up. Patients were randomized to one of the four iptacopan arms (10, 50, 100 [in Part 2 only], and 200 mg bid) or placebo. In this analysis, we report efficacy and biomarker data assessed at 6 months and treatment-emergent adverse events (AEs) assessed for the entire study duration. In addition to the pre-specified efficacy analysis of Part 2 at 6 months, Post hoc analyses combining data from Parts 1 and 2 were also performed. 46 and 66 patients were randomized in Parts 1 and 2, respectively. In Part 2, 58 patients completed 6 months of treatment. Demographic and baseline characteristics were generally well-balanced across all arms. The primary analysis yielded a statistically significant dose-response effect (1-sided p=0.038) of iptacopan versus placebo at 3 months, with maximal reduction in UPCR achieved with iptacopan 200 mg bid (23%; 80% CI: 8–34% using MCP-mod; Primary results were presented at 58thERA-EDTA Congress 2021 as late-breaking clinical trial ). UPCR continued to decrease between 3 and 6 months in the higher dosed iptacopan arms in Part 2, albeit with a wider 80% CI reflecting the smaller sample size. To allow better comparison with the primary analysis at 3 months, a Post hoc analysis of pooled data from Parts 1 and 2 was performed. The results indicated UPCR reduction from baseline up to 6 months in iptacopan 200 mg bid arm by up to 40% (80% CI: 16–53% using MCP-mod model) and at least 28% (80% CI: 3–46% using MMRM model) versus placebo (Figure 1). Sustained inhibition of AP biomarkers including plasma Bb, serum Wieslab, and urinary C5b-9 through 6 months was also observed with all doses of iptacopan above 10 mg bid (Figure 2). Iptacopan had a well-tolerated safety profile, with no deaths, no serious adverse events (SAEs) suspected to be treatment-related, and no serious infections caused by encapsulated bacteria. Iptacopan was well tolerated and led to continuous reduction in proteinuria and strong inhibition of AP activity through 6 months in patients with IgAN. These data are consistent with previous findings from the interim analysis at 3 months and support further evaluation of iptacopan in the ongoing Phase 3 APPLAUSE-IgAN trial (NCT04578834).

P053 The intestinal complement system and its role in dysregulation of the intestinal B-cell compartment in Crohn’s Disease patients

Abstract Background For several decades, there is growing evidence that a hyperactive B-cell compartment may be involved in the disturbed mucosal immune response in Crohn’s disease (CD) patients. This is reflected by approximately one third of all CD patients displaying an excessive production of autoantibodies against the intestinal M-cell expressed FimH receptor glycoprotein 2 (GP2) which inhibits induction of adaptive immunity against adherent-invasive flagellated bacteria. However, underlying mechanisms of an imbalanced B-cell compartment in CD patients still remain elusive. Given that the complement system plays a critical role in the detection and clearance of bacteria and promotes B-cell immunity, we asked if the complement system contributes to a dysregulated B-cell response in CD. Methods Systematical expression analyses of the intestinal complement components were performed in IBD patients, including CD and ulcerative colitis (UC) patients, versus non-IBD controls. Additionally, activity of the three activation pathways of complement system was studied in serum samples of CD patients and controls. Further, immunoglobulin levels in intestinal biopsies, sera and fecal samples were analyzed. Results CD patients, but no UC patients, showed increased expression of the early classical complement pathway components C1QA, C1QB, C1S, C2, C3, C4A, CR1 and CR2 in sigmoidal biopsy samples that does not differ significantly between remission and active disease state. This could be verified by immunohistochemistry, displaying an over-representation of mucosal C1q, C3 and B-cell expressed CR2 (also CD21) in colon biopsies of CD patients in remission. In line with this, CD patients in remission present with enhanced activity of the classical as well as alternative pathway of complement activation in serum compared to non-IBD controls. Accordingly, high protein levels of C3 cleavage fragments were detected in fecal samples from CD patients in contrast to non-IBD controls. While there were no differences in systemic immunoglobulin levels in serum, intestinal IgM was increased in CD patients in remission. Notably, fecal IgA levels were strongly diminished in these patients, while expression of the polymeric immunoglobulin receptor was not affected. Conclusion In summary, our findings demonstrate an augmented activation of the intestinal complement system that may potentially be involved in the etiology of CD. Expansion of mucosal IgM+/CR2+ B cells together with a reduced fecal IgA level, points to a locally disturbed induction of intestinal IgA secreting plasma cells in CD patients.

RHEOPHERESIS IN THE TREATMENT OF AGE-RELATED MACULAR DEGENERATION.

Evaluation of the long-term effect of rheopheresis treatment of dry form of age-related macular degeneration (AMD). The treatment group consisted of 65 patients and 55 patients in the control group, with a minimum follow-up period of 60 months. The basic treatment consisted of 8 rheopheresis procedures, and the additional treatment (booster therapy) of 2 rheopheresis procedures 1.5-2 years after the basic treatment. We evaluated changes in best corrected visual acuity, anatomical effect, electrical activity of the retina, haematological, biochemical and immunological parameters. Rheopheresis treatment contributed significantly: 1) to stabilisation of best corrected visual acuity of the treated patients, which initially showed an insignificant increased during the 2-years follow-up period, and then slightly decreased. By contrast, visual acuity decreased in the control group, to an insignificant degree up to 4 years, then statistically significantly. 2) to an improvement of the morphological findings in 62.4% of treated patients compared to 7.5% in the control group, while disease progression to stage 3 (neovascular form of the disease or geographic atrophy) with a significant decrease of visual acuity occurred in only 7.1% of treated patients, versus 37.0% in the control group. 3) to regression, even to the attachment of drusenoid pigment epithelial detachment (DPED). To a reduction of the area of DPED in 80.4% of treated patients, in contrast with ansteaincrease in the area of DPED in 47.1% of patients in the control group, and the development of new DPED in only 2 eyes of treated patients compared with 16 eyes of patients in the control group. 4) to a preservation of the integrity of the ellipsoid layer in the fovea in 68.2% of the treated patients, while by contrast we found a damaged ellipsoid layer in the fovea in 66.6% of the control patients. 5) to a stabilisation of the activity of ganglion cells, the pineal system and the activity of the central area of the retina, with eccentricity between 1.8° and 30° in the treated patients, compared to alteration in the control group manifested mainly after 3.5 years of the follow-up period. 6) to a statistically significant improvement in rheological parameters, thereby increasing flow in microcirculation and positively influencing the metabolism in the retina. Also to a positive effect on the classical, alternative and lectin pathway of complement activation, a reduction in the level of proprotein convertase subtilisin kexin 9 (PCSK9), and thus also the level of LDLcholesterol, and 7) Additional treatment with 2 RHF procedures (so-called "booster therapy") seems to be a safe and suitable method of prolonging the stabilisation phase, or even improving visual acuity, anatomical and functional findings. We demonstrated positive changes in anatomical, functional and humoral parameters upon rheopheresis treatment of AMD. Their correlation provides a real possibility to identify patients at risk and to manage an individualised regime of rheopheresis therapy. This method of treatment is effective and safe, with a low percentage of non-serious adverse effects.

Effects of terrestrial lipid blend on the growth performance, body composition, nonspecific immunity, antioxidant status and stress resistance when the dietary n‐3 long‐chain polyunsaturated fatty acids requirements are met in juvenile Japanese sea bass ( Lateolabrax japonicus )

This study was conducted to investigate the effects of replacing dietary lipid source FO with a terrestrial lipid blend (LB) on the growth performance, body composition and immunity of juvenile Japanese sea bass when the dietary n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) requirements are met (Lateolabrax japonicus). Two types of experimental diets were formulated with the total FO (the control) or the LB (linseed oil and lard = 1:1). A 56-day feeding trial was conducted in floating cages with three replicates for each treatment. The results indicated that a significantly higher specific growth rate (SGR) and feed efficiency ratio (FER) occurred in fish that were fed the LB diet compared with the control group (p < 0.05). There was no significant difference in the survival rate, body composition or body indicates between the groups (p > 0.05). The respiratory burst, alternative complement pathway activity, lysozyme activity, cytokine genes expression and air exposure test results indicated that the replacement of FO with LB did not significantly affect the nonspecific immunity or stress resistance (p > 0.05). The serum antioxidant enzyme activities and liver tissue antioxidant-related gene expression were significantly higher in the control group than in the other group (p < 0.05). Therefore, the terrestrial lipid blends from linseed and lard (1:1) could be used as an alternative for dietary fish oil without compromising the growth performance, nonspecific immunity and resistance to stress in juvenile Japanese sea bass.

Sars-Cov-2 Induced Endotheliopathy and the Impact on Clinical Outcomes in Critically Ill Pediatric Patients

Background: Coronavirus disease-19 (COVID-19) is an acute respiratory illness caused by the SARS-COV-2 virus. Patients with COVID-19 infection can present with thrombosis in the setting of inflammation (thromboinflammation), presumably from endothelial dysfunction, or “endotheliopathy”.Yu et al demonstrated in vitro that the spike protein subunit of SARS-COV2 acts as a potent activator of the alternative complement pathway (AP), one of three complement pathways within the innate immune system. Satyam et alreported the deposition of complement components on lung tissue of patients who succumbed to COVID-19, consistent with activation of classical and alternate pathways. These studies suggest complement dysregulation potentially causing endotheliopathy in COVID-19 patients.Thrombomodulin (TM) is an endothelial glycoprotein that plays two crucial roles in maintaining a healthy endothelium - as a natural anticoagulant and a negative regulator of complement. TM shed into the circulation due to endothelial injury can be measured in the plasma as soluble TM (sTM). Goshua et al showed elevated sTM in an adult cohort of patients with COVID-19. However, it is yet to be demonstrated if there is any correlation between endothelial injury and AP activation in COVID-19, or if either play a role in clinical outcome in the pediatric population.Objective: To 1) assess endothelial injury and AP activation in a cohort of critically ill pediatric patients with COVID-19 by measuring sTM and Ba (an AP activation product); 2) determine the correlation between endothelial injury and AP activation; and 3) analyze the utility of sTM and Ba in predicting pediatric clinical outcomes.Methods:We collected plasma samples of patients admitted to the Pediatric Intensive Care Unit and found to be positive for SARS-CoV-2 between Dec 2, 2020 and Jan 22, 2021 at Texas Children's Hospital. For controls, we collected plasma samples from pediatric patients undergoing preoperative clearance, all at their baseline state of health.sTM levels and Ba levels were measured in plasma samples using commercially available TM and Ba ELISA kits. sTM greater than 7.6 ng/ml (based on the assay range in adults) and Ba greater than 1080 ng/ml (based on data from adult healthy controls) were considered elevated.Data regarding demographics, length of ICU stay, clinical indicators of end organ damage- mechanical ventilation, dialysis, use of vasopressors, ECMO, mortality were obtained retrospectively via chart review. Inclusion criteria included all patients with a positive SARS-COV2 PCR admitted to the ICU. Exclusion criteria was age greater than 21 years, pregnant female, patients with known inflammatory or complement-mediated disorders.Statistical analysis: For sTM and Ba levels between control and COVID-19 patients, mean +/- standard deviation was calculated and significance determined with an unpaired t-test. Fischer exact test, Wilcoxon rank sum and Pearson product-moment correlation tests were used for statistical analysis of clinical outcomes as appropriate. A p-value <0.05 was considered statistically significant.Results:A total of 38 control patients and 33 COVID-19 patients were enrolled. Ba and sTM levels were both significantly higher in the COVID-19 pediatric patients compared to the controls (Fig. 1). Within the COVID-19 patient cohort, 61% (n=20) had elevated sTM and 42% (n=14) had elevated Ba levels. There was a moderately positive correlation between sTM and plasma Ba levels in the COVID-19 cohort (Fig. 2).Within the COVID-19 patients' cohort, though higher Ba levels were not associated with an increased rate of intubation, they were associated with an increased duration of mechanical ventilation (p=.039) for those intubated (Table 1). Elevated sTM was associated with increased vasopressor use (p=.011). Although other clinical outcome variables did not reach statistical significance likely owing to small numbers, overall trend indicated worse outcomes in patients with elevated sTM.Conclusions:Our findings are consistent with the hypothesis that SARS-COV-2 activates AP and causes endothelial injury in children. The positive correlation between sTM and Ba suggest interplay between inflammation, coagulation and endotheliopathy supporting thromboinflammation in COVID-19. Higher sTM and Ba levels indicated worse clinical outcomes in children, but larger studies are needed to confirm our findings. [Display omitted] DisclosuresSartain: Alexon Pharamaceuticals: Membership on an entity's Board of Directors or advisory committees.

Genetic abnormalities in biopsy-proven, adult-onset hemolytic uremic syndrome and C3 glomerulopathy

Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) have been linked to mutations in many of the proteins that are involved in alternative complement pathway activation. Age and etiology confounded, the prevalence of such mutations has been reported to be over 30 to 50% in these diseases. However, the cohorts studied included many children or individuals with a familial history of complement-related disorders and genetic tests were usually limited to exome sequencing of known causative or risk-associated genes. In this study, a retrospective adult cohort of 35 patients with biopsy-proven thrombotic microangiopathy (the largest in Canada) and 10 patients with C3 glomerulopathy was tested through an extended exome panel to identify causative defects in associated or candidate genes including those of the alternative and terminal complement pathways. A variant of unknown significance was also analyzed for pathogenicity through in vitro studies. To our surprise, the prevalence of known causative or risk-associated variants in either of these cohorts was found to be less than ~ 15% overall. However, the panel used and analyses carried out allowed to identify novel variants of potential clinical significance and a number of candidate genes. The prevalence of known genetic defects in adult-onset aHUS and C3G is thus probably much lower than 30 to 50%. Our results also point towards the importance of investigating diseases of the alternative complement pathway through extended exome panels and in vitro analyses.Key messagesThe alternative complement pathway plays a major role in the pathogenesis of hemolytic uremic syndrome and C3 glomerulopathy.Based on previous studies, both disorders have been commonly linked to variants in the various intermediates that sustain or regulate this pathway.The prevalence of such mutations in the adult-onset and sporadic forms of these diseases is probably much lower than expected based on larger series.The sporadic forms of complementopathies are likely to involve additional genes that are yet to be uncovered.

The effects of various organic fertilizers with or without adsorbents on the productivity, antioxidant status and immune responses of Nile tilapia raised in cement ponds

The present study investigated the role of fish sludge (FS) as an organic fertilizer in fish ponds alone or in combined with some industrial wastes such as sawdust (SD) and sugar beet pulp (SBP) and their influences on productivity, blood biochemistry, antioxidant and immune status of Nile tilapia compared to the well-known fertilizer cow dung. Fish were distributed into the following experimental groups: control group (with no fertilizers); CD group (cow dung fertilized group); FS group (fish sludge fertilized group); FS + SD (fertilized with fish sludge combined with sawdust); FS + SBP group (fertilized with fish sludge combined with sugar beet pulp) in 3 replicates ponds per each. Fish raised in ponds fertilized with FS + SD, FS, and FS + SBP respectively, recorded higher final weight (FW), weight gain (WG), specific growth rate (SGR), and protein efficiency ratio (PER) values and the lowest feed conversion ratio (FCR) values when compared to the control group. Fish raised in CD fertilized ponds showed significantly higher alanine aminotransferase (ALT) levels. While, FS + SD group had the highest GSH content followed by FS and FS + SBP groups. The catalase (CAT) activity was also significantly higher in FS, FS + SD and FS + SB groups compared to control and CD groups. FS significantly reduced the Malondialdehyde (MDA) content than control and CD groups and a more significant reduction was recorded in FS + SD and FS + SBP groups. The highest total antioxidant activity (TAC) was recorded in the FS + SBP group. The results also showed that FS + SBP followed by FS + SD obtained the highest Alternative Complement pathway (ACH50) activity. FS, FS + SD and FS + SBP groups showed significantly higher lysozyme activity than the CD group. All added fertilizers significantly increased the NBT value compared to the control group. In conclusion, fish sludge showed a more promising property as an organic fertilizer in fish ponds than cow dung, particularly in the presence of adequate water purifying material such as sawdust or sugar beet pulp.

Complement factor B in high glucose–induced podocyte injury and diabetic kidney disease

The role and mechanisms for upregulating complement factor B (CFB) expression in podocyte dysfunction in diabetic kidney disease (DKD) are not fully understood. Here, analyzing Gene Expression Omnibus GSE30528 data, we identified genes enriched in mTORC1 signaling, CFB, and complement alternative pathways in podocytes from patients with DKD. In mouse models, podocyte mTOR complex 1 (mTORC1) signaling activation was induced, while blockade of mTORC1 signaling reduced CFB upregulation, alternative complement pathway activation, and podocyte injury in the glomeruli. Knocking down CFB remarkably alleviated alternative complement pathway activation and DKD in diabetic mice. In cultured podocytes, high glucose treatment activated mTORC1 signaling, stimulated STAT1 phosphorylation, and upregulated CFB expression, while blockade of mTORC1 or STAT1 signaling abolished high glucose–upregulated CFB expression. Additionally, high glucose levels downregulated protein phosphatase 2Acα (PP2Acα) expression, while PP2Acα deficiency enhanced high glucose–induced mTORC1/STAT1 activation, CFB induction, and podocyte injury. Taken together, these findings uncover a mechanism by which CFB mediates podocyte injury in DKD.

BCX9930, an Oral Factor D Inhibitor in Development for Treatment of Complement-Mediated Diseases, Inhibits Complement Alternative Pathway (AP) Activity in Healthy Subjects

BCX9930, an Oral Factor D Inhibitor in Development for Treatment of Complement-Mediated Diseases, Inhibits Complement Alternative Pathway (AP) Activity in Healthy Subjects

Profile of Immunoglobulin G N-Glycome in COVID-19 Patients: A Case-Control Study.

Coronavirus disease 2019 (COVID-19) remains a major health challenge globally. Previous studies have suggested that changes in the glycosylation of IgG are closely associated with the severity of COVID-19. This study aimed to compare the profiles of IgG N-glycome between COVID-19 patients and healthy controls. A case-control study was conducted, in which 104 COVID-19 patients and 104 age- and sex-matched healthy individuals were recruited. Serum IgG N-glycome composition was analyzed by hydrophilic interaction liquid chromatography with the ultra-high-performance liquid chromatography (HILIC-UPLC) approach. COVID-19 patients have a decreased level of IgG fucosylation, which upregulates antibody-dependent cell cytotoxicity (ADCC) in acute immune responses. In severe cases, a low level of IgG sialylation contributes to the ADCC-regulated enhancement of inflammatory cytokines. The decreases in sialylation and galactosylation play a role in COVID-19 pathogenesis via the activation of the lectin-initiated alternative complement pathway. IgG N-glycosylation underlines the complex clinical phenotypes of SARS-CoV-2 infection.

Clinical epidemiological study on the association between neutrophil extracellular traps and acute myocardial infarction among coronary atherosclerotic heart disease

Objective To investigate the change and its roles of neutrophil extracellular traps (NETs) in peripheral blood from patients with coronary atherosclerotic heart disease (CAHD) during their acute myocardial infarction (AMI) and post operation of coronary artery bypass graft (CABG), and to proride effective prevention and control of CAHD and AMI. Methods A total of 52 patients with AMI and 52 healthy controls (HCs) were involved in this study. The levels of NETs, fragment a of the factor B (Ba), fragment a of the 5th complement (C5a) and myeloperoxidase (MPO) in peripheral blood were detected by enzyme linked immunosorbent assay (ELISA) at the onset of AMI [pre-treatment (PRT) group], post-operative treatment group (POT group) and in HC group. Their differences between the groups were detected by t test while the relationships between the parameters in PRT group were tested by Pearson correlation analysis. Results All the parameters from PRT and POT group were higher than those in the HC group, respectively. The levels of cardiac troponin I (cTnI), NETs, Ba, C5a and MPO in PRT group were higher than those in POT group [(0.279±0.132) ng/ml vs.(0.016±0.008) ng/ml, P Conclusions The persistent high level of NETs and its related high activity of complement alternative pathway in CAHD during the onset of AMI and post-treatment of CABG might contribute to the progression of the disease and the recurrence of myocardial infarction. Intervention on the formation of NETs might be one of the potential pathways to prevent the progression of CHAD and the occurrence of AMI.

Complement Alternative and Mannose-Binding Lectin Pathway Activation Is Associated With COVID-19 Mortality.

BackgroundThe SARS-CoV-2 infection triggers excessive immune response resulting in increased levels of pro-inflammatory cytokines, endothelial injury, and intravascular coagulopathy. The complement system (CS) activation participates to this hyperinflammatory response. However, it is still unclear which activation pathways (classical, alternative, or lectin pathway) pilots the effector mechanisms that contribute to critical illness. To better understand the immune correlates of disease severity, we performed an analysis of CS activation pathways and components in samples collected from COVID-19 patients hospitalized in Grenoble Alpes University Hospital between 1 and 30 April 2020 and of their relationship with the clinical outcomes.MethodsWe conducted a retrospective, single-center study cohort in 74 hospitalized patients with RT-PCR-proven COVID-19. The functional activities of classical, alternative, and mannose-binding lectin (MBL) pathways and the antigenic levels of the individual components C1q, C4, C3, C5, Factor B, and MBL were measured in patients’ samples during hospital admission. Hierarchical clustering with the Ward method was performed in order to identify clusters of patients with similar characteristics of complement markers. Age was included in the model. Then, the clusters were compared with the patient clinical features: rate of intensive care unit (ICU) admission, corticoid treatment, oxygen requirement, and mortality.ResultsFour clusters were identified according to complement parameters. Among them, two clusters revealed remarkable profiles: in one cluster (n = 15), patients exhibited activation of alternative and lectin pathways and low antigenic levels of MBL, C4, C3, Factor B, and C5 compared to all the other clusters; this cluster had the higher proportion of patients who died (27%) and required oxygen support (80%) or ICU care (53%). In contrast, the second cluster (n = 19) presented inflammatory profile with high classical pathway activity and antigenic levels of complement components; a low proportion of patients required ICU care (26%) and no patient died in this group.ConclusionThese findings argue in favor of prominent activation of the alternative and MBL complement pathways in severe COVID-19, but the spectrum of complement involvement seems to be heterogeneous requiring larger studies.

Quantitative Alterations in Complement Alternative Pathway and Related Genetic Analysis in Severe Phenotype Preeclampsia.

Preeclampsia and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome share many clinical and biologic features with thrombotic microangiopathy syndromes caused by complement abnormalities. Our hypothesis was that similar functional and genetic alterations in the complement alternative pathway (CAP) are present in these disorders of pregnancy. We conducted quantitative analysis of proteins involved in CAP using ELISA and nephelometry on prospectively collected blood samples from patients with severe phenotype preeclampsia (defined as delivery ≤34 weeks due to preeclampsia), HELLP syndrome, or eclampsia, and matched normotensive controls (n=25 in each arm) between 2011 and 2016. Sequencing was performed to interrogate 14 genes encoding CAP components. Both groups were similar in age, gravidity, parity, marital status, and race. The study group had a higher BMI (mean±SD, 32±8 versus 25±4 kg/m2; P=0.002) and earlier gestational age at delivery (32.5±3.6 versus 40.3±1 weeks; P<0.001). Serologic studies demonstrated elevated Bb subunit (median [range], 1.2 [0.5-4.3] versus 0.6 [0.5-1] μg/ml; P<0.001), complement C5 concentration (28 [18-33] versus 24 [15-34] mg/dl; P=0.03), and sMAC (371 [167-761] versus 184 [112-249] ng/ml; P<0.001) concentrations in patients with preeclampsia. Two thirds of patients with preeclampsia had at least one nonsynonymous sequence variant in CAP genes. Patients with severe phenotype preeclampsia manifest functional alterations in CAP activation. Genetic variants in the CAP genes were detected in several patients, but a larger population study is necessary to fully evaluate genetic risk. Genetic screening and complement-targeted treatment may be useful in risk stratification and novel therapeutic approaches.

Fermented goat's milk modulates immune response during iron deficiency anemia recovery.

Iron deficiency and iron overload can affect the normal functioning of the innate and adaptive immune responses. Fermented milk products may enhance immune functions, but little is known about the effect of fermented milks on modulation of the immune response during iron deficiency anemia and recovery with normal or high dietary iron intake. Eighty male Wistar rats were randomly assigned to a control group fed a standard diet or to an anemic group fed a diet deficit in iron. Control and anemic groups were fed for 30 days with diets based on a fermented goat's or cow's milk product, with normal iron content or iron overload. In general, during anemia recovery lectin and alternative complement pathway activity and lactoferrin decreased, because it improves iron homeostasis, which is critically important in immune system functions. Fermented goat's milk diet enhanced immune function during iron deficiency recovery, suppressed oxidant-induced eotaxin and fractalkine expression due to the concurrent reduction of free radical production and pro-inflammatory cytokines, and decreased monocyte chemoattractant protein-1 and monocyte migration and adhesion. The increase in interferon-γ can confer immunological colonization of gut microbiota and downregulate inflammation. Fermented goat's milk consumption enhances immune function, modifying complement pathway activity and decreasing pro-inflammatory cytokines as well as lactoferrin concentration, due to the improvement of iron homeostasis, which is critically important in the normal function of the immune system. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Genome-wide association studies for production, respiratory disease, and immune-related traits in Landrace pigs

Identification of a quantitative trait locus (QTL) related to a chronic respiratory disease such as Mycoplasmal pneumonia of swine (MPS) and immune-related traits is important for the genetic improvement of disease resistance in pigs. The objective of this study was to detect a novel QTL for a total of 22 production, respiratory disease, and immune-related traits in Landrace pigs. A total of 874 Landrace purebred pigs, which were selected based on MPS resistance, were genotyped using the Illumina PorcineSNP60 BeadChip. We performed single nucleotide polymorphism (SNP)-based and haplotype-based genome-wide association studies (GWAS) to detect a novel QTL and to evaluate the possibility of a pleiotropic QTL for these traits. SNP-based GWAS detected a total of six significant regions in backfat thickness, ratio of granular leucocytes to lymphatic cells, plasma concentration of cortisol at different ages, and complement alternative pathway activity in serum. The significant region detected by haplotype-based GWAS was overlapped across the region detected by SNP-based GWAS. Most of these detected QTL regions were novel regions with some candidate genes located in them. With regard to a pleiotropic QTL among traits, only three of these detected QTL regions overlapped among traits, and many detected regions independently affected the traits.

Effects of dietary butyric acid glycerides on growth performance, haemato‐immunological and antioxidant status of yellowfin seabream (Acanthopagrus latus) fingerlings

Sixty-day research was conducted to investigate the effects of dietary butyric acid glyceride (BAG) on the performance of Acanthopagrus latus fingerlings (8.59 ± 0.33 g). Experimental feeds were prepared by supplementing a commercial feed (crude protein: 50%, crude lipid: 15%) with graded levels of BAG including 0 (control), 0.25% (BAG0.25), 0.5% (BAG0.5) and 1% (BAG 1). One hundred and twenty fish (10 fish in each tank) were stocked in twelve 300-L tanks then fed with the experimental feeds twice daily. Growth and feed utilization in fish fed BAG-supplemented diets were better than the control (p < 0.05). Fish fed BAG1 diet had more red and white blood cells counts than the other groups. Total immunoglobulin content and lysozyme activity in the skin mucus increased by increasing dietary BAG. Fish in BAG1 group had more skin mucosal alternative complement pathway activity than the other groups (p < 0.05). Liver catalase and glutathione S transferase activities increased in a dose–response manner to dietary BAG level. Fish in BAG1 group showed higher liver glutathione reductase activity than the other treatments. According to the findings of this study, supplementing diet with 1% of BAG can promote growth performance and health conditions in A. latus fingerlings.

Influence of the Immunomodulator AVIGEN to Broiler Chicken Humoral Immune Factors

The nonspecific immune response plays an important role in organism's defense against a variety of pathogens. Two major factors in this process are blood serum lysozyme and alternative pathway of complement activation (APCA). Over the past few decades, the application of various substances, targeting improved levels of natural immunity have become part of the mainstream trends in livestock rearing programs. The current study examined the influence of the polybacterial immunomodulator AVIGEN on the performance of the aforementioned immune factors among broiler chicken hybrids. The experimental group demonstrated better overall performance for both parameters of interest. APCA activity for the treated group (549.10±19.69 CH50) was significantly higher compared to the result obtained for the controls (377.40±9.58 CH50), (P<0.001). Results for the other parameter were even more indicative. The measured concentration of the serum lysozyme for the treated group was twice as high compared to the control birds - 6.17±0.49 mg/L vs. 2.99±0.27 mg/L, respectively. Therefore, the introduction of the AVIGEN immunomodulator to animals' diet has strong potential to improve natural humoral immunity in poultry farming.

A small fragment of factor B as a potential inhibitor of complement alternative pathway activity

BackgroundThe complement system is a key player in innate immunity and a modulator of the adaptive immune system. Among the three pathways of complement, the alternative pathway (AP) accounts for most of the complement activation. Factor B (FB) is a major protease of the AP, making it a promising target to inhibit the AP activity in conditions of uncontrolled complement activation. MethodsBased on the data obtained from sequence analysis and conformational changes associated with FB, we expressed and purified a recombinant FB fragment (FBfr). We tested the inhibitory activity of the protein against the AP by in vitro assays. ResultsFBfr protein was proven to inhibit the complement AP activity when tested by C3b deposition assay and rabbit erythrocyte hemolytic assay. ConclusionOur recombinant FBfr was able to compete with the native human FB, which allowed it to inhibit the AP activity. This novel compound is a good candidate for further characterization and testing to be used in complement diagnostic tests and as a drug lead in the field of complement therapeutics.