The role of complement C3 in the outcome of regional myocardial infarction.

Coronary heart disease leading to myocardial ischemia is a major cause of heart failure. A hallmark of heart failure is myocardial fibrosis. Using a murine model of myocardial ischemia/reperfusion injury (IRI), we showed that, following IRI, in mice genetically deficient in the central factor of complement system, C3, myocardial necrosis was reduced compared with WT mice. Four weeks after the ischemic period, the C3-/- mice had significantly less cardiac fibrosis and better cardiac function than the WT controls. Overall, our results suggest that innate immune response through complement C3 plays an important role in necrotic cell death, which contributes to the cardiac fibrosis that underlies post-infarction heart failure.

Circulating complement factor H levels are associated with disease severity and relapse in autoimmune hepatitis.

Background & Aims: The complement system plays pivotal roles in innate immunity. Mannose-binding lectin-associated serine protease (MASP)-2 plays essential roles in the activation of the lectin complement pathway. Complement factor H acts as a critical negative regulator of the alternative complement pathway. The association of circulating MASP-2 and factor H with the clinical features of patients with autoimmune hepatitis (AIH) is unclear. Methods: A total of 63 patients with AIH were recruited for this study. The serum levels of MASP-2, factor H, and C3a were measured, and their associations with the clinical features of AIH were analyzed. Results: The circulating C3a levels were higher in patients with AIH than in the controls. The circulating MASP-2 and factor H levels were decreased depending on the severity of AIH. Multivariate logistic analysis showed that low circulating factor H levels were associated with features of severe AIH (odds ratio 0.36; 95% CI 0.15-0.84; p = 0.018). Multivariate Cox proportional hazards model analysis showed that low circulating factor H levels were associated with a high incidence of relapse (hazard ratio: 5.19; 95% CI 1.07-25.2; p = 0.041). Patients with low circulating factor H levels showed higher rates of relapse than the controls (log-rank, p = 0.006). Conclusion: Circulating factor H levels were associated with severe disease and with the incidence of relapse, suggesting a role for the complement system in the pathophysiology of AIH. Lay summary: Autoimmune hepatitis is an immune-mediated liver disease. Despite effective treatments, patients often relapse, which can lead to clinical deterioration and adverse outcomes. Herein, we studied the importance of the complement system (a form of innate immunity) in patients with autoimmune hepatitis. We found that the levels of a protein called factor H, which regulates the complement system, could be a potential biomarker of disease severity and relapse, and could even have therapeutic potential for patients with AIH.

Estimation of associations between 10 common gene polymorphisms and gastric cancer: evidence from a meta-analysis.

AIMS: Associations between polymorphisms in cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4)/mannose-binding lectin (MBL)/interleukin-4 (IL-4)/interleukin-6 (IL-6)/phospholipase C ε-1 (PLCE1) and gastric cancer (GC) were already reported by many studies, yet the conclusions of these studies were somehow controversial. The aim of this meta-analysis was to better clarify associations between polymorphisms in CTLA-4/MBL/IL-4/IL-6/PLCE1 and GC by combing the results of all relevant studies. METHODS: Eligible studies were searched from PubMed, Embase, WOS and CNKI. We used Review Manager to combine the results of individual studies. RESULTS: Forty-three studies were included in this meta-analysis. Combined results revealed that CTLA-4 rs5742909 (dominant comparison: OR: 1.58, 95 % CI: 1.01 to 2.48; allele comparison: OR: 1.69, 95 % CI: 1.12 to 2.56) and PLCE1 rs2274223 (dominant comparison: OR: 0.84, 95 % CI: 0.72 to 0.98; recessive comparison: OR: 1.23, 95 % CI: 1.08 to 1.40; over-dominant comparison: OR: 1.16, 95 % CI: 1.00 to 1.34; allele comparison: OR 0.88, 95 % CI 0.78 to 0.99) polymorphisms were significantly associated with GC in the general population. We also obtained similar significant associations with GC for rs5742909 and rs2274223 polymorphisms in East Asians. Nevertheless, no positive results were observed for the other eight investigated polymorphisms. CONCLUSION: Collectively, this meta-analysis demonstrated that CTLA-4 rs5742909 and PLCE1 rs2274223 polymorphisms may confer susceptibility to GC, especially for East Asians.

The role of oligosaccharides and polysaccharides of xylan and mannan in gut health of monogastric animals.

Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.

Development of a C3c-based ELISA method for the determination of anti-complementary potency of Bupleurum polysaccharides.

Traditionally, determination of inhibitory potency of complement inhibitors is performed by the hemolytic assay. However, this assay is not applicable to the lectin pathway, thus impeding the understanding of complement inhibitors against the overall function of the complement system. The main objective of our study was to develop a specific enzyme-linked immunosorbent assay (ELISA) as an alternative method to assess the anti-complement activity, particularly against the lectin pathway. By using respective coating substrates against different activation pathways, followed by capturing the stable C3c fragments, our ELISA method can be used to screen complement inhibitors against the classical pathway and the lectin pathway. The inhibitory effect of suramin on the classical pathway, as measured by our hemolytic assay is consistent with previous reports. Further assessment of suramin and Bupleurum polysaccharides against the lectin pathway showed a good reproducibility of the method. Comparison of the lectin pathway IC50 between Bupleurum smithii var. parvifolium polysaccharides (1.055 mg/mL) and Bupleurum chinense polysaccharides (0.98 mg/mL) showed that, similar to the classical and alterative pathway, these two Bupleurum polysaccharides had comparable anti-complementary properties against the lectin pathway. The results demonstrate that the described ELISA assay can compensate for the shortcomings of the hemolytic assay in lectin pathway.