Elevated Complement Research Articles

Acute myocardial dysfunction in lupus: outcomes in Asian Indians.

Acute myocardial dysfunction is an uncommon but potentially fatal complication in systemic lupus erythematosus (SLE). We describe the outcome in a small series of Asian Indian patients and examine associated factors. SLE patients who fulfilled the 2012 SLICC criteria and developed new-onset myocardial dysfunction were included in this retrospective case series. Acute myocardial dysfunction was defined as global hypokinesia and left ventricular ejection fraction (LVEF)<50% on echocardiography (with or without symptoms) in patients with SLE. Survival was assessed using Kaplan-Meier survival analysis and Cox regression. This study included 37 patients with mean age 28.2 ± 11.2years and median (range) LVEF of 35% (18-48%) at presentation. A majority had active disease, with SLEDAI-2k ≥ 5 in 26 (of 28). All patients received oral corticosteroids and a majority received additional immunosuppression, including pulse methylprednisolone in 28 and cyclophosphamide in 27. Nine patients died during hospitalisation (25%), a majority due to infections. Death was significantly associated with elevated procalcitonin at presentation (p = 0.05), elevated white cell count (p = 0.02) and low complement C3 (p = 0.03). In those who survived, long-term outcomes were good, with complete myocardial recovery in 14 (64%). A higher ejection fraction at presentation was associated with complete recovery. In this small series of patients of SLE with acute myocardial dysfunction, we report a significant in-hospital mortality due to infections. Many of the patients who died had elevated procalcitonin at presentation. A diligent search for infection seems prudent in lupus patients who present with acute myocardial dysfunction. Key Points • In patients of SLE with acute myocardial dysfunction who were treated with immunosuppression, there was significant short-term mortality due to infections. • This mortality was associated with elevated procalcitonin at baseline and may suggest some of them had pre-existing hidden sepsis. • A prudent search for infections in these patients before immunosuppression may help to decrease short-term mortality.

Elevated C-reactive protein and complement C3 levels are associated with preterm birth: a nested case\u2013control study in Chinese women

BackgroundCurrently, there are many studies researched the associations between maternal serum inflammatory indicators (i.e. ferritin, C-reactive protein [CRP], C3 and C4) and preterm birth (PTB). The results, however, are inconsistent. Therefore, the aim of this study was to estimate the relationship between maternal serum inflammatory indicators and PTB in a nested case-control (NCC)study.MethodsA NCC study was conducted by Guangxi Birth Cohort Study which enrolled a total of 6203 pregnant women between 50/7 and 346/7 weeks of gestational age (wGA) from six cities in China between 2015 and 2016. There were 206women who delivered preterm (< 370/7 wGA), and 412 women who delivered term birth, those women were matched by maternal age, birth place, gender of infants, and wGA at blood collection.The inflammatory indicators were quantified by immunoturbidimetric methods.ResultsHighest quartile concentrations of all inflammatory indicators were determined versus median. After adjusting for maternal age, high levels of CRP (CRP > 16.60 mg/L) are related to the risk of PTB (OR = 2.16, 95% CI: 1.02–4.56, p = 0.044) in the first trimester. The association of C3 was extremely related to those who delivered PTB (OR = 2.53, 95% CI: 1.14–5.64, p = 0.023) in the first trimester. Moreover, no significant associations were found in C4 (p = 0.079) and ferritin (p = 0.067) between PTB.ConclusionsElevated concentrations of CRP and C3 in the first trimester were associated with increased risk of PTB. Inflammatory indicators may act a pivotal part in early diagnosis and prognosis of PTB.

Association of systemic lupus erythematosus disease activity index score with clinical and laboratory parameters in pediatric onset systemic lupus erythematosus.

Objective:To determine the association of systemic lupus erythematosus disease activity index (SLEDAI) score in pediatric onset SLE (p-SLE) with clinical and laboratory parameters.Methods:This cross sectional observational study was conducted at Division of Rheumatology, Fatima Memorial Hospital, Lahore from November 2018 to January 2019. Total 23 patients diagnosed with p-SLE having onset of symptoms at ≤ 18 years of age, irrespective of their current age at presentation, of either gender, fulfilling criteria of 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria were enrolled. Patients’ clinical symptoms and laboratory parameters were reviewed, SLEDAI scores were calculated. Collected Data were entered in proforma and analyzed on SPSS version 23.Results:There were 91.3% females. Mean age at diagnosis was 11years ± 4years. At presentation patients had hematological involvement 69.6% followed by mucocutaneous symptoms 65.2% and renal involvement 21.6%. ANA by IFA was positive in all, while anti-ds-DNA was positive in 78.3% patients. SLEDAI score was ≥6 in 87% patients, average SLEDAI score was higher in patients with renal involvement (p=0.06). Elevated ESR (r=0.48, p=0.02), Anti-dsDNA (r=0.44, p=0.05) and low complement levels (p=0.03) were significantly positively correlated, while hemoglobin (r= -0.43, p=0.04) was negatively correlated with the SLEDAI score.Conclusion:In this study, patients with Lupus Nephritis had high SLEDAI scores. Elevated Anti-dsDNA titer, ESR, low complement levels and hemoglobin were significantly associated with high SLEDAI scores. We recommend that SLEDAI score should be calculated in p-SLE patients for stringent disease monitoring and treatment.

Herpes zoster laryngitis

Herpes zoster infection is due to reactivation of the latent varicella zoster virus. It is often seen in persons with impaired immunity or stress and characterized by one-side herpetic vesicular eruptions and neuralgia. A 45-year-old male presented with sore throat, hiccups, voice changes, and dry cough. Laryngeal examinations showed edema and eruptions over the left side of the larynx. He had herpetic vesicles over the left concha and external auditory canal. Elevated complement fixation titer confirmed the diagnosis of the herpes zoster. The patient was treated with acyclovir and steroid. Patients improved symptomatically after 10 days of treatment. This clinical condition should be kept in mind when the patient will present with unilateral sore throat, voice changes, and hiccups.

The complement cascade in Alzheimer's disease: a systematic review and meta-analysis.

Genetic evidence implicates a causal role for the complement pathway in Alzheimer's disease (AD). Since studies have shown inconsistent differences in cerebrospinal fluid (CSF) and peripheral blood complement protein concentrations between AD patients and healthy elderly, this study sought to summarize the clinical data. Original peer-reviewed articles measuring CSF and/or blood concentrations of complement or complement regulator protein concentrations in AD and healthy elderly control (HC) groups were included. Of 2966 records identified, means and standard deviations from 86 studies were summarized as standardized mean differences (SMD) by random effects meta-analyses. In CSF, concentrations of clusterin (NAD/NHC = 625/577, SMD = 0.53, Z8 = 8.81, p < 0.005; I2 < 0.005%) and complement component 3 (C3; NAD/NHC = 299/522, SMD = 0.45, Z3 = 3.21, p < 0.005; I2 = 68.40%) were significantly higher in AD, but differences in C1q, C-reactive protein (CRP), serum amyloid protein (SAP), and factor H concentrations were not significant. In peripheral blood, concentrations of CRP were elevated in AD (NAD/NHC = 3404/3332, SMD = 0.44, Z43 = 3.43, p < 0.005; I2 = 93.81%), but differences between groups in C3, C4, C1-inhibitor, SAP, factor H and clusterin concentrations were not significant,and inconsistent between studies. Of 64 complement pathway proteins or regulators in the quantitative synthesis, trends in C1q, factor B, C4a, and late-stage complement pathway components (e.g. C9) in blood, C4 in CSF, and the membrane attack complex in blood and CSF, might be investigated further. The results collectively support elevated complement pathway activity in AD, which was best characterized by increased CSF clusterin concentrations and less consistently by CSF C3 concentrations. Complement activity related to anADdiagnosis was not reflected consistently by the peripheral blood proteins investigated.

Coccidioidomycosis in solid organ transplant recipients.

The purpose of the review is an update of diagnosis and treatment of coccidioidomycosis infection in solid organ transplant (SOT) patients. Endemic fungal infections continue to be a cause of serious morbidity and mortality in transplant recipients. In transplant patients there are recommendations regarding screening in areas that are endemic for coccidioidomycosis. This screening involves serologic testing and chest imaging. In endemic areas pretransplant seropositivity varies from 1.4 to 5.6%. In immunocompromised patients with elevated complement fixation titers, evaluation of cerebrospinal fluid is recommended even in the absence of symptoms. Although coccidioidomycosis can be a self-limited disease in immunocompotent patients, all SOT patients should be treated regardless of severity. This may include intravenous amphotericin B in severe cases and fluconazole therapy in milder episodes. In those SOT recipients with evidence of prior coccidioidomycosis, lifelong secondary prophylaxis with fluconazole given risk of recurrent disease. Coccidioidomycosis continues to be a cause of serious morbidity and mortality in transplant recipients but with proper screening and treatment can be successfully managed.

Elevated surface-bound complement FH alters the function of platelets and monocytes in FHR1/3 null healthy individuals

Complement factor H (FH) and FH-related proteins (FHRs), structurally similar proteins are involved in the regulation of complement activation. Homozygous deletion of FHR 1 and 3 proteins (FHR1/3−/−) is known as a risk factor for disorders such as aHUS and SLE, characterised by thrombo-inflammatory complications. Interestingly, FHR1/3−/− genotype also exists as polymorphism in healthy population of various ethnicities around the world including 8–10% Indians. In an effort to understand the functional role of this polymorphism, we describe in this study an elevated surface-bound FH on platelets and monocytes, but not other blood cells in FHR1/3 −/− healthy individuals. The FHR1/3−/− platelets displayed diminish ability to form aggregates in response to agonists in vitro. The FHR1/3−/− monocytes displayed elevated secretion of TNFα, IL1β, IL6 and IL10 in response to TLR ligands. However, exogenous FH limits platelet aggregates formation as well as cytokine secretion in monocytes. Therefore, observations together suggest a differential regulation of platelets and monocytes by FH-FHR1/3 axis in healthy individuals. While these findings will need more detailed investigation, it is clear that the connection between FH-FHR axis and thrombo-inflammatory complications is likely to be complex in diseases including aHUS and SLE, and provide interesting new directions for future study.

Complement Factor H Modulates Splenic B Cell Development and Limits Autoantibody Production.

Complement factor H (CFH) has a pivotal role in regulating alternative complement activation through its ability to inhibit the cleavage of the central complement component C3, which links innate and humoral immunity. However, insights into the role of CFH in B cell biology are limited. Here, we demonstrate that deficiency of CFH in mice leads to altered splenic B cell development characterized by the accumulation of marginal zone (MZ) B cells. Furthermore, B cells in Cfh−/− mice exhibit enhanced B cell receptor (BCR) signaling as evaluated by increased levels of phosphorylated Bruton's tyrosine kinase (pBTK) and phosphorylated spleen tyrosine kinase (pSYK). We show that enhanced BCR activation is associated with uncontrolled C3 consumption in the spleen and elevated complement receptor 2 (CR2, also known as CD21) levels on the surface of mature splenic B cells. Moreover, aged Cfh−/− mice developed splenomegaly with distorted spleen architecture and spontaneous B cell-dependent autoimmunity characterized by germinal center hyperactivity and a marked increase in anti-double stranded DNA (dsDNA) antibodies. Taken together, our data indicate that CFH, through its function as a complement repressor, acts as a negative regulator of BCR signaling and limits autoimmunity.

Elevated serum complement levels and higher gene copy number of complement C4B are associated with hypertension and effective response to statin therapy in childhood-onset systemic lupus erythematosus (SLE)

ObjectiveSystemic lupus erythematosus (SLE) features high frequency of cardiovascular disease (CVD) and fluctuating complement levels. The clinical trial Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) aimed to evaluate whether atorvastatin...

Elevated Complement C3 and C4 Levels are Associated with Postnatal Pregnancy-Related Venous Thrombosis.

High levels of complement C3 are associated with venous thrombosis (VT) in the general population. We investigated if high C3 and C4 levels were associated with pregnancy-related VT. We undertook the Norwegian VIP study, a case-control study of VT in pregnancy or within 3 months postpartum (cases, n = 313) and women without pregnancy-related VT (controls, n = 353). Determinants of C3 and C4 in the control women were investigated with linear regression and the odds ratio (OR) for pregnancy-related VT was calculated with logistic regression. We found that levels of C3 and C4 were associated with body mass index (BMI), C-reactive protein (CRP); with the coagulation factors (F) fibrinogen, FVIII, and FIX; and with the coagulation inhibitors antithrombin, protein C, protein S, and tissue factor pathway inhibitor. These associations were influenced by CRP levels. The crude OR for pregnancy-related VT was 1.8 (95% confidence interval [CI], 1.1-3.0) for C3 above the 90th percentile and 2.0 (95% CI, 1.2-3.2) for C4 above the 90th percentile. Stratification in antenatal and postnatal VT showed that C3 and C4 were only associated with postnatal VT with an OR for high C3 of 3.0 (95% CI, 1.8-5.0), and for high C4 of 2.6 (95% CI, 1.5-4.6). Adjustment for high FIX and BMI reduced the ORs. We conclude that the association between postnatal VT and C3 and C4 suggests that there is clinically relevant crosstalk between the complement and the coagulation system.

Neuroinflammation in Gulf War Illness is linked with HMGB1 and complement activation, which can be discerned from brain-derived extracellular vesicles in the blood

Cognitive dysfunction and neuroinflammation are conspicuously observed in Gulf War Illness (GWI). We investigated whether brain inflammation in GWI is associated with activation of high mobility group box-1 (HMGB1) and complement-related proteins in neurons and astrocytes, and brain inflammation can be tracked through neuron-derived extracellular vesicles (NDEVs) and astrocyte-derived EVs (ADEVs) found in the circulating blood. We exposed animals to GWI-related chemicals pyridostigmine bromide, DEET and permethrin, and moderate stress for 28 days. We performed behavioral tests 10 months post-exposure and quantified activated microglia and reactive astrocytes in the cerebral cortex. Then, we measured the concentration of HMGB1, proinflammatory cytokines, and complement activation-related proteins in the cerebral cortex, and NDEVs and ADEVs in the circulating blood. Cognitive impairments persisted in GWI rats at 10 months post-exposure, which were associated with increased density of activated microglia and reactive astrocytes in the cerebral cortex. Moreover, the level of HMGB1 was elevated in the cerebral cortex with altered expression in the cytoplasm of neuronal soma and dendrites as well as the extracellular space. Also, higher levels of proinflammatory cytokines (TNFa, IL-1b, and IL-6), and complement activation-related proteins (C3 and TccC5b-9) were seen in the cerebral cortex. Remarkably, increased levels of HMGB1 and proinflammatory cytokines observed in the cerebral cortex of GWI rats could also be found in NDEVs isolated from the blood. Similarly, elevated levels of complement proteins seen in the cerebral cortex could be found in ADEVs. The results provide new evidence that persistent cognitive dysfunction and chronic neuroinflammation in a model of GWI are linked with elevated HMGB1 concentration and complement activation. Furthermore, the results demonstrated that multiple biomarkers of neuroinflammation could be tracked reliably via analyses of NDEVs and ADEVs in the circulating blood. Execution of such a liquid biopsy approach is especially useful in clinical trials for monitoring the remission, persistence or progression of brain inflammation in GWI patients with drug treatment.

Thrombotic Microangiopathy after Pediatric Allogeneic Stem Cell Transplant: Potential Early Markers to Predict Individuals at High-Risk

Background Transplant associated thrombotic microangiopathy (TMA) is a severe complication of stem cell transplant (SCT), characterized by endothelial damage leading to microangiopathic hemolytic anemia, thrombocytopenia and organ damage. Mild cases of TMA do not require treatment, but severe cases are associated with organ damage and mortality. Soluble suppression of tumorigenicity-2 (ST2) is a member of the interleukin 1 receptor family and has been associated with cardiac as well as endothelial injury. Elevated soluble terminal complement complex (sC5b-9) has recently been shown to be associated with high-risk TMA. We hypothesize that both complement activation (indicated by increased Sc5b9) and endothelial injury (indicated by increased ST2) occur early in the transplant process, setting up later tissue injury and organ damage, and these markers may be used to predict individuals at high-risk of later TMA, perhaps even before the start of the conditioning regimen. Methods We evaluated 276 consecutive pediatric allogeneic SCT patients at our center. Patients were diagnosed with high-risk TMA if they received eculizumab therapy and demonstrated laboratory and clinical markers of TMA on at least two consecutive tests, including evidence of complement activation, or the patient demonstrated evidence of microangiopathy on a tissue specimen. We compared early serum levels of ST2 and sC5b-9 between patients who later developed or did not develop high-risk TMA at two-time points: prior to the start of the chemotherapy/radiation (baseline) and 7 days after stem cell infusion (Day +7). Results 42 patients (15%) developed high-risk TMA requiring eculizumab at a median of 23 days (IQR: 10-46) post-SCT. Demographics were similar between the groups (Table 1). Patients with high-risk TMA were more likely to receive grafts from mismatched unrelated donors (52% vs. 29%, p=0.013). Patients with high-risk TMA had increased rates of acute GVHD at day 100 (33% vs 11%, p=0.001) and 1-year all-cause mortality (31 vs. 14%, 0.013). ST2 and sC5b-9 levels were significantly higher at baseline and day +7 in patients with high risk-TMA (Table 2). The area under the curve for high risk TMA using a log fold change in ST2 and sC5b-9 from baseline to day +7 was 0.802 (Figure 1). Discussion Plasma levels of sC5b-9 and ST2 are increased at baseline and 7 days after SCT in allogeneic recipients who develop high-risk TMA compared with those who do not. These data suggest complement activation and endothelial injury associated with high-risk TMA may occur before SCT and/or early on after the initiation of therapy. These markers could be used to identify high risk persons for increased screening and we are investigating whether genetic susceptibility, diagnosis of prior therapy might lead to increased baseline complement activity and pre-existing endothelial injury that might be ameliorated prior to start of transplant.

Pathological significance of urinary complement activation in diabetic nephropathy: A full view from the development of the disease.

Aims/IntroductionThe aim of the present study was to obtain a full view of the changes of urinary complement activation products in the development of diabetic nephropathy and explore their possible significance in the disease process.Materials and methodsA total of 62 patients at different stages of diabetic nephropathy, 20 diabetes patients without nephropathy and 20 healthy persons were enrolled. Urinary complement activation products, including C3a, C5a and C5b‐9, were measured, and their associations with the progression of the disease were analyzed.ResultsThe urinary complement activation products increased markedly since the proteinuria stage, and were parallel with the progression of diabetic nephropathy. More severe renal tubular damage was observed in patients with higher levels of urinary complement activation products. The urinary complement activation products levels correlated closely with renal tubulointerstitial injury score and relative tubular interstitial volume. Multivariate regression analysis showed that elevated urinary complement activation products were independent risk factors for tubular injury in diabetic nephropathy patients.ConclusionsUrinary complement activation might have a role in renal tubular interstitial injury in patients with diabetic nephropathy, especially in patients at a later stage of the disease.

IL-6 Receptor Inhibition by Tocilizumab Attenuated Expression of C5a Receptor 1 and 2 in Non-ST-Elevation Myocardial Infarction.

Background: Elevated interleukin-6 (IL-6) and complement activation are associated with detrimental effects of inflammation in coronary artery disease (CAD). The complement anaphylatoxins C5a and C3a interact with their receptors; the highly inflammatory C5aR1, and the C5aR2 and C3aR. We evaluated the effect of the IL-6 receptor (IL-6R)-antagonist tocilizumab on the expression of the anaphylatoxin receptors in whole blood from non-ST-elevation myocardial infarction (NSTEMI) patients. Separately, anaphylatoxin receptor expression in peripheral blood mononuclear cells (PBMC) from patients with different entities of CAD was investigated.Materials and Methods: NSTEMI patients were randomized to one dose of tocilizumab (n = 28) or placebo (n = 32) and observed for 6 months. Whole blood samples drawn at inclusion, at day 2, 3 and after 6 months were used for mRNA isolation. Plasma was prepared for analysis of complement activation measured as sC5b-9 by ELISA. Furthermore, patients with different CAD entities comprising stable angina pectoris (SAP, n = 22), non-ST-elevation acute coronary syndrome (NSTE-ACS, n = 21) and ST-elevation myocardial infarction (STEMI, n = 20) were included. PBMC was isolated from blood samples obtained at admission to hospital and mRNA isolated. Anaphylatoxin-receptor-expression was analyzed with qPCR using mRNA from whole blood and PBMC, respectively.Results: Our main findings were (i) Tocilizumab decreased C5aR1 and C5aR2 mRNA expression significantly (p < 0.001) and substantially (>50%) at day 2 and 3, whereas C3aR expression was unaffected. (ii) Tocilizumab did not affect complement activation. (iii) In analyzes of different CAD entities, C5aR1 expression was significantly increased in all CAD subgroups compared to controls with the highest level in the STEMI patients (p < 0.001). For C5aR2 and C3aR the expression compared to controls were more moderate with increased expression of C5aR2 in the STEMI group (p < 0.05) and C3aR in the NSTE-ACS group (p < 0.05).Conclusion: Expression of C5aR1 and C5aR2 in whole blood was significantly attenuated by IL-6R-inhibition in NSTEMI patients. These receptors were significantly upregulated in PBMC CAD patients with particularly high levels of C5aR1 in STEMI patients.

CblC Type Methylmalonic Aciduria with a Novel Homozygous Mutation: A Case Report

Background CombinedMethylmalonic Aciduria (MMA), and homocystinuria CblC type is the most common inborn error of cobalamin metabolism with 77 mutations identified till date in the MMACHC gene. The disease has early and late presentations with varied clinical features. Case report A pair of preterm monochorionic twins was born to non-consanguineous parents with history of 2 previous infant deaths with suspected MMA. The twins became symptomatic in second week with severe neutropenia, thrombocytopenia, progressive encephalopathy and eczema without anemia, metabolic acidosis or hyperammonemia. Investigation revealed elevated plasma Complement 3 (C3) acyl carnitine and very high MMA levels in urine. Genetic testing revealed a novel large deletion mutation in chromosome 1 which comprised of the whole MMACHC gene confirming the diagnosis of CblC type of MMA. The mutation was homozygous despite parents being unrelated and was identified in both parents later. Both twins responded transiently to treatment with hydroxycobalamin. Conclusion Large deletion in the MMACHC genewhich was identified in a homozygous state in our twins is previously unreported. The phenotypic features are described.

Measurement of soluble CD59 in CSF in demyelinating disease: Evidence for an intrathecal source of soluble CD59

Background: CD59, a broadly expressed glycosylphosphatidylinositol-anchored protein, is the principal cell inhibitor of complement membrane attack on cells. In the demyelinating disorders, multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), elevated complement protein levels, including soluble CD59 (sCD59), were reported in cerebrospinal fluid (CSF). Objectives: We compared sCD59 levels in CSF and matched plasma in controls and patients with MS, NMOSD and clinically isolated syndrome (CIS) and investigated the source of CSF sCD59 and whether it was microparticle associated. Methods: sCD59 was quantified using enzyme-linked immunosorbent assay (ELISA; Hycult; HK374-02). Patient and control CSF was subjected to western blotting to characterise anti-CD59-reactive materials. CD59 was localised by immunostaining and in situ hybridisation. Results: CSF sCD59 levels were double those in plasma (CSF, 30.2 ng/mL; plasma, 16.3 ng/mL). Plasma but not CSF sCD59 levels differentiated MS from NMOSD, MS from CIS and NMOSD/CIS from controls. Elimination of microparticles confirmed that CSF sCD59 was not membrane anchored. Conclusion: CSF levels of sCD59 are not a biomarker of demyelinating diseases. High levels of sCD59 in CSF relative to plasma suggest an intrathecal source; CD59 expression in brain parenchyma was low, but expression was strong on choroid plexus (CP) epithelium, immediately adjacent the CSF, suggesting that this is the likely source.

In Vitro and In Vivo Biocompatibility Evaluation of Polyallylamine and Macromolecular Heparin Conjugates Modified Alginate Microbeads

Host reactivity to biocompatible immunoisolation devices is a major challenge for cellular therapies, and a human screening model would be of great value. We designed new types of surface modified barium alginate microspheres, and evaluated their inflammatory properties using human whole blood, and the intraperitoneal response after three weeks in Wistar rats. Microspheres were modified using proprietary polyallylamine (PAV) and coupled with macromolecular heparin conjugates (Corline Heparin Conjugate, CHC). The PAV-CHC strategy resulted in uniform and stable coatings with increased anti-clot activity and low cytotoxicity. In human whole blood, PAV coating at high dose (100 µg/ml) induced elevated complement, leukocyte CD11b and inflammatory mediators, and in Wistar rats increased fibrotic overgrowth. Coating of high dose PAV with CHC significantly reduced these responses. Low dose PAV (10 µg/ml) ± CHC and unmodified alginate microbeads showed low responses. That the human whole blood inflammatory reactions paralleled the host response shows a link between inflammatory potential and initial fibrotic response. CHC possessed anti-inflammatory activity, but failed to improve overall biocompatibility. We conclude that the human whole blood assay is an efficient first-phase screening model for inflammation, and a guiding tool in development of new generation microspheres for cell encapsulation therapy.

C-Reactive Protein Binds to Cholesterol Crystals and Co-Localizes with the Terminal Complement Complex in Human Atherosclerotic Plaques

Inflammation is a part of the initial process leading to atherosclerosis and cholesterol crystals (CC), found in atherosclerotic plaques, which are known to induce complement activation. The pentraxins C-reactive protein (CRP), long pentraxin 3 (PTX3), and serum amyloid P component (SAP) are serum proteins associated with increased risk of cardiovascular events and these proteins have been shown to interact with the complement system. Whether the pentraxins binds to CC and mediate downstream complement-dependent inflammatory processes remains unknown. Binding of CRP, PTX3, and SAP to CC was investigated in vitro by flow cytometry and fluorescence microscopy. CRP, PTX3, and SAP bound to CC in a concentration-dependent manner. CRP and PTX3 interacted with the complement pattern recognition molecule C1q on CC by increasing the binding of both purified C1q and C1q in plasma. However, CRP was the strongest mediator of C1q binding and also the pentraxin that most potently elevated C1q-mediated complement activation. In a phagocytic assay using whole blood, we confirmed that phagocytosis of CC is complement dependent and initiated by C1q-mediated activation. The pathophysiological relevance of the in vitro observations was examined in vivo in human atherosclerotic plaques. CRP, PTX3, and SAP were all found in atherosclerotic plaques and were located mainly in the cholesterol-rich necrotic core, but co-localization with the terminal C5b-9 complement complex was only found for CRP. In conclusion, this study identifies CRP as a strong C1q recruiter and complement facilitator on CC, which may be highly relevant for the development of atherosclerosis.

Dietary arachidonic acid affects immune function and fatty acid composition in cultured rabbitfish Siganus rivulatus

The marbled spinefoot rabbitfish (Siganus rivulatus) is an economically valuable fish species that has potential for commercial production in aquaculture. To overcome challenges in its sustainable production, a formulated diet is required for imparting health and robustness. This study evaluates the effect of dietary supplementation with arachidonic acid (ARA; 20:4n-6) on growth, survival, immune function and fatty acid composition of red blood cells (RBCs) in rabbitfish. We conducted two feeding trials using juvenile fish (to evaluate growth and survival) and adults (to evaluate immune function and fatty acid incorporation). Fish were fed diets supplemented with three different levels of ARA (in % of total fatty acids): 0.6 (unsupplemented control), 2.6 (moderate) and 4.7 (high). The fish fed with moderate ARA levels exhibited improved (p < 0.05) growth over the control and the high ARA level groups. During an outbreak of Streptococcus iniae, fish fed with moderate ARA survived significantly (p < 0.05) better (89%) than the control and the high ARA groups (59% and 48%, respectively). Moderate ARA supplementation resulted in elevated lysozyme and complement levels in the plasma of rabbitfish. A significant increase in the total serum immunoglobulin levels was observed in both the medium and the high ARA level groups; however, a decrease in antiprotease activity was recorded in the supplemented groups as compared to the control.Fatty acid analysis in fish red blood cells revealed a significant (p < 0.05) increase in the proportion of ARA of total fatty acids in the groups fed with the medium and the high ARA level diets (9.5% and 11.2%, respectively, compared to 7.1% in the control). Concomitantly, there was a decrease in the proportion of eicosapentaenoic acid (EPA; 20:5n-3), dihomo-γ linolenic acid (DGLA; 20:3n-6) and several 18-carbon unsaturated fatty acids in these groups.In conclusion, ARA in rabbitfish feeds improved growth, survival as well as innate and acquired humoral immune functions. Thus ARA supplementation in the diet of this species could be a valuable step towards establishing the commercial culture of rabbitfish.

Bipolar disorder patients display reduced serum complement levels and elevated peripheral blood complement expression levels.

Bipolar disorder (BD) patients have recently been shown to exhibit increased proinflammatory cytokine levels indicating the role of inflammation in this disease. As inflammatory responses often include complement level alterations and complement production is influenced by cytokines, we aimed to find out whether complement system is activated in BD in a time-dependent manner and complement factors are involved in BD pathogenesis. Serum C4, factor B, sC5b-9 and neuron-specific enolase levels were measured by enzyme-linked immunosorbent assay, whereas peripheral blood mononuclear cell messenger RNA (mRNA) expression levels of C1q, C4, factor B and CD55 were measured by real-time polymerase chain reaction in chronic BD patients (n=22), first episode BD patients (n=24) and healthy controls (n=19). Serum complement levels were significantly reduced in chronic BD patients as compared with first episode BD patients and healthy controls. Serum levels of complement factors showed significant inverse correlation with disease duration, severity of manic symptoms and serum neuron-specific enolase levels. In chronic BD patients, peripheral blood mononuclear cell mRNA expression levels of C1q, C4 and factor B were significantly elevated, whereas the mRNA expression level of the complement inhibitor CD55 was significantly reduced. Our results suggest that complement factor levels are reduced in BD presumably due to overconsumption of the complement system and complement production is increased at mRNA level possibly as a compensation measure. Complement factors might potentially be used as indicators of disease severity, neuronal loss and cognitive dysfunction.