Evolving Concepts in the Pathogenesis of NASH: Beyond Steatosis and Inflammation

Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis and inflammation and, in some patients, progressive fibrosis leading to cirrhosis. An understanding of the pathogenesis of NASH is still evolving but current evidence suggests multiple metabolic factors critically disrupt homeostasis and induce an inflammatory cascade and ensuing fibrosis. The mechanisms underlying these changes and the complex inter-cellular interactions that mediate fibrogenesis are yet to be fully elucidated. Lipotoxicity, in the setting of excess free fatty acids, obesity, and insulin resistance, appears to be the central driver of cellular injury via oxidative stress. Hepatocyte apoptosis and/or senescence contribute to activation of the inflammasome via a variety of intra- and inter-cellular signalling mechanisms leading to fibrosis. Current evidence suggests that periportal components, including the ductular reaction and expansion of the hepatic progenitor cell compartment, may be involved and that the Th17 response may mediate disease progression. This review aims to provide an overview of the pathogenesis of NASH and summarises the evidence pertaining to key mechanisms implicated in the transition from steatosis and inflammation to fibrosis. Currently there are limited treatments for NASH although an increasing understanding of its pathogenesis will likely improve the development and use of interventions in the future.     

Potential Roles of Selectins in Periodontal Diseases and Associated Systemic Diseases: Could They Be Targets for Immunotherapy?

Periodontal diseases are predisposing factors to the development of many systemic disorders, which is often initiated via leukocyte infiltration and vascular inflammation. These diseases could significantly affect human health and quality of life. Hence, it is vital to explore effective therapies to prevent disease progression. Periodontitis, which is characterized by gingival bleeding, disruption of the gingival capillary’s integrity, and irreversible destruction of the periodontal supporting bone, appears to be caused by overexpression of selectins in periodontal tissues. Selectins (P-, L-, and E-selectins) are vital members of adhesion molecules regulating inflammatory and immune responses. They are mainly located in platelets, leukocytes, and endothelial cells. Furthermore, selectins are involved in the immunopathogenesis of vascular inflammatory diseases, such as cardiovascular disease, diabetes, cancers, and so on, by mediating leukocyte recruitment, platelet activation, and alteration of endothelial barrier permeability. Therefore, selectins could be new immunotherapeutic targets for periodontal disorders and their associated systemic diseases since they play a crucial role in immune regulation and endothelium dysfunction. However, the research on selectins and their association with periodontal and systemic diseases remains limited. This review aims to discuss the critical roles of selectins in periodontitis and associated systemic disorders and highlights the potential of selectins as therapeutic targets.     

结核菌H37Ra在小鼠体内诱导的免疫应答

目的检测结核菌H37Ra免疫小鼠后产生的特异性细胞免疫和体液免疫应答水平。方法将BALB/c小鼠随机分为H37Ra组、BCG组和生理盐水(NS)组,分别进行免疫,免疫8周后处死小鼠,分离血清,ELISA间接法测定血清特异性抗PPDIgG抗体的水平,流式细胞分析仪检测脾脏T淋巴细胞亚群的变化。脾淋巴细胞经体外培养、PPD刺激后,MTT法检测脾淋巴细胞的刺激指数,ELISA法检测培养上清液中IFN-γ和IL-4的水平。结果H37Ra免疫小鼠血清中抗PPDIgG抗体、脾脏CD3+T细胞和CD4+T细胞的百分率、脾淋巴细胞刺激指数、IFN-γ和IL-4水平均显著高于NS对照组,但与BCG组差异无显著意义。各组间脾脏CD8+T细胞、CD4+T/CD8+T比值差异均无显著意义。结论H37Ra免疫小鼠后,可以产生特异性的细胞免疫和体液免疫应答,有望成为结核疫苗的候选抗原。     

人巨细胞病毒ISCOMs对小鼠细胞免疫应答的调节作用

应用人巨细胞病毒被膜蛋白制备实验型免疫刺激复活物 (ISCOMs)疫苗能诱发细胞免疫反应。对小鼠 1次接种ISCOMs未能诱生明显细胞毒性T细胞 (Tc)及自然杀伤细胞 (NK)细胞活性增加 ,但能使L3T4及其与LyT2的比值增加。第 2次免疫后小鼠Tc及NK细胞活性明显增加。提示该疫苗有可能在预防人巨细胞病毒 (HC MV)原发感染中发挥作用。     

Mold,Mycotoxins and a Dysregulated Immune System: A Combination of Concern?

Fungi represent one of the most diverse and abundant eukaryotes on earth. The interplay between mold exposure and the host immune system is still not fully elucidated. Literature research focusing on up-to-date publications is providing a heterogenous picture of evidence and opinions regarding the role of mold and mycotoxins in the development of immune diseases. While the induction of allergic immune responses by molds is generally acknowledged, other direct health effects like the toxic mold syndrome are controversially discussed. However, recent observations indicate a particular importance of mold/mycotoxin exposure in individuals with pre-existing dysregulation of the immune system, due to exacerbation of underlying pathophysiology including allergic and non-allergic chronic inflammatory diseases, autoimmune disorders, and even human immunodeficiency virus (HIV) disease progression. In this review, we focus on the impact of mycotoxins regarding their impact on disease progression in pre-existing immune dysregulation. This is complemented by experimental in vivo and in vitro findings to present cellular and molecular modes of action. Furthermore, we discuss hypothetical mechanisms of action, where evidence is missing since much remains to be discovered.     

甲型肝炎减毒活疫苗(H2株)和灭活疫苗(L8株)诱导小鼠体液及细胞免疫应答

目的评估甲型肝炎减毒活疫苗和灭活疫苗的免疫学效果。方法用甲型肝炎减毒活疫苗(H2株)和灭活疫苗(L8株)分别经腹腔免疫BALBc小鼠后,用ELISA法检测血清中抗HAVIgG、TNFα、IFNγ和IL2;用流式细胞仪对全血中T细胞亚群分类;3HTdR掺入法检测T淋巴细胞增殖。结果减毒活疫苗组在初免后诱导的体液和细胞免疫水平均低于灭活疫苗组,加强免疫后,与灭活疫苗相当。灭活疫苗组IFNγ的峰值出现时间较减毒活疫苗组晚,但水平较高。结论两种疫苗均可诱导体液和细胞免疫应答,减毒活疫苗进行加强免疫后可诱导更好的系统免疫应答。     

Iodine Excess as an Environmental Risk Factor for Autoimmune Thyroid Disease

The global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to poor monitoring, is currently a more frequent occurrence than iodine deficiency. Iodine excess is a precipitating environmental factor in the development of autoimmune thyroid disease. Excessive amounts of iodide have been linked to the development of autoimmune thyroiditis in humans and animals, while intrathyroidal depletion of iodine prevents disease in animal strains susceptible to severe thyroiditis. Although the mechanisms by which iodide induces thyroiditis are still unclear, several mechanisms have been proposed: (1) excess iodine induces the production of cytokines and chemokines that can recruit immunocompetent cells to the thyroid; (2) processing excess iodine in thyroid epithelial cells may result in elevated levels of oxidative stress, leading to harmful lipid oxidation and thyroid tissue injuries; and (3) iodine incorporation in the protein chain of thyroglobulin may augment the antigenicity of this molecule. This review will summarize the current knowledge regarding excess iodide as an environmental toxicant and relate it to the development of autoimmune thyroid disease.     

Etiology of IBD—Is It Still a Mystery?

Inflammatory bowel diseases (IBD), including colitis ulcerosa and Crohn’s disease, are chronic diseases of the gastrointestinal tract for which the cause has not been fully understood. However, it is known that the etiology is multifactorial. The multidirectional network of interactions of environmental, microbiological and genetic factors in predisposed persons lead to an excessive and insufficiently inhibited reaction of the immune system, leading to the development of chronic inflammation of the gastrointestinal walls, the consequence of which is the loss of the function that the intestine performs, inter alia, through the process of fibrosis. Detailed knowledge of the pathways leading to chronic inflammation makes it possible to pharmacologically modulate disorders and effectively treatthese diseases. In this review, we described the primary and adaptive immune system response in the gut and the known immune pathogenetic pathways leading to the development of IBD. We also described the process leading to intestinal tissue fibrosis, which is an irreversible consequence of untreated IBD.