肠道菌群失衡在结直肠癌发病过程中的作用

结直肠癌是结肠癌和直肠癌的总称,目前其病因和发病机制尚未明确。现认为结直肠癌的发生可能与肠道微环境、宿主遗传易感性和高动物蛋白饮食等因素有关。近年来,随着微生态学的发展,肠道菌群与结直肠癌发病的关系日益受到关注。此文就结直肠癌发生过程中肠道菌群的变化、对结直肠癌的影响以及微生态制剂对结直肠癌的治疗作用等相关研究作一综述。     

饮食结构影响肠道微生态在结直肠肿瘤中的作用

肠道微生态成员在人体内数量巨大,饮食结构是肠型形成的重要影响因素,不同饮食结构能够显著改变肠道微生态的组成和代谢。肠道微生态参与结直肠肿瘤等多种疾病的发生、发展,饮食-肠道微生态-宿主与疾病有显著的相关性和相互作用。西方化饮食增加结直肠肿瘤的发病风险,素食饮食、地中海饮食和生酮饮食可降低其发病风险,其中地中海饮食的保护...     

肠道菌群与结直肠癌的相关性研究

结直肠癌(colorectal cancer,CRC)是常见的恶性肿瘤之一。CRC的发生是由环境、饮食及生活方式与遗传因素协同作用而引起的。近年来,肠道菌群在CRC中的作用越来越受到重视。诸多研究表明,肠道菌群及其代谢产物在结肠黏膜从正常上皮到腺瘤及癌变过程中起重要作用。本文就肠道菌群与CRC的最新研究进展作一概述。     

肠道微生态与饮食

肠道菌群与宿主的关系受饮食因素影响。饮食中的营养物质可影响肠道微生物群落结构并为微生物的代谢提供底物,而微生物代谢产物被宿主吸收后可影响宿主生理功能。因此,肠道微生态与饮食和健康密切相关。本文就肠道微生态与饮食的关系作一综述。     

益生菌对大肠癌的防治作用及机制研究进展

大肠癌(colorectal cancer,CRC)是目前最常见的恶性肿瘤之一,CRC的发生及发展与肠道微生态有密切的关系。肠道菌群对于肠道功能的维持及内环境的平衡具有重要作用。肠道菌群失调可通过多种途径促进CRC的发生。益生菌是调节肠道微生态的主要方法,并可通过多种机制发挥抗肿瘤作用。本文综合目前研究进展,从调节肠道代谢产物、保护肠道黏膜屏障完整性、抑制肠道炎症、调节宿主免疫反应、促进凋亡和细胞分化、抑制细胞增殖等方面总结益生菌对癌前病变及CRC的防治作用及机制,为临床肠道微生态的调节及CRC的防治提供指导。     

结直肠癌的预防

结直肠癌是一种可预防的疾病,目前国际上正在研究可防止腺瘤－癌顺序启动和进展的饮食干预和化学预防策略。愈来愈多的证据表明,内镜下息肉摘除和早期发现可减少结直肠癌的发生率和死亡率。 饮食干预 食物直接与肠道接触,影响其生理和代谢。饮食因素与结直肠癌的确切关系仍有争议,多数证据提示,人均肉类、脂肪和蛋白质消费量与结直肠癌发病率呈正相关,植物性饮食则呈负相关。 一、纤维 以高纤维饮食为主的非洲乡村人群中结直肠癌的发病率较低。纤维的膨胀特性稀释了结肠内的致癌物质,结肠内细菌发酵改变了肠道生理和菌群平衡,从而使…     

肠道微生态在放射性肠炎防治中的研究进展北大核心CSCD

放射性肠炎是放射治疗引起的肠道并发症。辐射引起肠道微生态改变、肠黏膜屏障破坏,肠道共生微生物及其代谢产物通过影响肠道黏膜屏障免疫功能在辐射损伤和辐射抗性中发挥一定作用。以肠微生态为靶点的微生态制剂和菌群移植可能为预防和治疗放射性肠炎提供新的方向。     

肠道微生态在放射性肠炎防治中的研究进展

放射性肠炎是放射治疗引起的肠道并发症。辐射引起肠道微生态改变、肠黏膜屏障破坏, 肠道共生微生物及其代谢产物通过影响肠道黏膜屏障免疫功能在辐射损伤和辐射抗性中发挥一定作用。以肠微生态为靶点的微生态制剂和菌群移植可能为预防和治疗放射性肠炎提供新的方向。     

防治结直肠肿瘤的新策略：中草药调控肠道菌群

肠道菌群失调(肠道微生物的组成和功能失衡)是结直肠癌(Colorectal Cancer, CRC)发展的关键因素之一,肠道菌群失调直接或间接诱发了一系列改变,从而影响和促进了结直肠肿瘤的发生和发展。中草药一直被视为一种天然制剂,应用在医学治疗上已经有了上千年历史,并且当前越来越受到重视,已经成为一种抗癌辅助治疗的新发展方向。中草药由于是天然产物,具有多种结构和药理作用,在结直肠癌患者和动物模型中被发现具有改善肠道菌群、修复肠道屏障和减轻炎症等作用。本文综述了中草药通过调节肠道菌群的策略来防治结直肠肿瘤,从一种新的方向提供治疗思路。     

肠道菌群对结直肠癌发生及其诊治作用的研究进展

结直肠癌是人类目前常见的癌症之一,是全球癌症相关死亡的第二大原因。肠道菌群在维持肠道正常生理环境方面发挥重要作用,包括能量代谢、与正常肠道屏障系统相互作用、促进上皮细胞存活等。随着研究的不断深入,越来越多的研究表明,肠道菌群在结直肠癌发生、发展中发挥重要作用。目前普遍认为,肠道菌群诱导的结直肠癌作用机制与细菌产生的毒素释放增强诱导DNA损伤、肠道有益菌衍生代谢物减少、肠道上皮屏障功能障碍或肠道菌群生态失调等因素有关。     

Role of diet and gut microbiota on colorectal cancer immunomodulation

Colorectal cancer(CRC) is one of the most commonly diagnosed cancers, and it is characterized by genetic and epigenetic alterations, as well as by inflammatory cell infiltration among malignant and stromal cells. However, this dynamic infiltration can be influenced by the microenvironment to promote tumor proliferation, survival and metastasis or cancer inhibition. In particular, the cancer microenvironment metabolites can regulate the inflammatory cells to induce a chronic inflammatory response that can be a predisposing condition for CRC retention. In addition, some nutritional components might contribute to a chronic inflammatory condition by regulating various immune and inflammatory pathways. Besides that, diet strongly modulates the gut microbiota composition,which has a key role in maintaining gut homeostasis and is associated with the modulation of host inflammatory and immune responses. Therefore, diet has a fundamental role in CRC initiation, progression and prevention. In particular,functional foods such as probiotics, prebiotics and symbiotics can have a potentially positive effect on health beyond basic nutrition and have antiinflammatory effects. In this review, we discuss the influence of diet on gut microbiota composition, focusing on its role on gut inflammation and immunity.Finally, we describe the potential benefits of using probiotics and prebiotics to modulate the host inflammatory response, as well as its application in CRC prevention and treatment.     

Probiotics,prebiotics and colorectal cancer prevention

Colorectal cancer (CRC), the third major cause of mortality among various cancer types in United States, has been increasing in developing countries due to varying diet and dietary habits and occupational hazards. Recent evidences showed that composition of gut microbiota could be associated with the development of CRC and other gut dysbiosis. Modulation of gut microbiota by probiotics and prebiotics, either alone or in combination could positively influence the cross-talk between immune system and microbiota, would be beneficial in preventing inflammation and CRC. In this review, role of probiotics and prebiotics in the prevention of CRC has been discussed. Various epidemiological and experimental studies, specifically gut microbiome research has effectively improved the understanding about the role of probiotics and microbial treatment as anticarcinogenic agents. A few human studies support the beneficial effect of probiotics and prebiotics; hence, comprehensive understanding is urgent to realize the clinical applications of probiotics and prebiotics in CRC prevention.     

Dismicrobism in inflammatory bowel disease and colorectal cancer: Changes in response of colocytes

Patients with inflammatory bowel disease (IBD) have an increased risk of 10%-15% developing colorectal cancer (CRC) that is a common disease of high economic costs in developed countries. The CRC has been increasing in recent years and its mortality rates are very high. Multiple biological and biochemical factors are responsible for the onset and progression of this pathology. Moreover, it appears absolutely necessary to investigate the environmental factors favoring the onset of CRC and the promotion of colonic health. The gut microflora, or microbiota, has an extensive diversity both quantitatively and qualitatively. In utero, the intestine of the mammalian fetus is sterile. At birth, the intestinal microbiota is acquired by ingesting maternal anal or vaginal organisms, ultimately developing into a stable community, with marked variations in microbial composition between individuals. The development of IBD is often associated with qualitative and quantitative disorders of the intestinal microbial flora (dysbiosis). The healthy human gut harbours about 10 different bacterial species distributed in colony forming units which colonize the gastrointestinal tract. The intestinal microbiota plays a fundamental role in health and in the progression of diseases such as IBD and CRC. In healthy subjects, the main control of intestinal bacterial colonization occurs through gastric acidity but other factors such as endoluminal temperature, competition between different bacterial strains, peristalsis and drugs can influence the intestinal microenvironment. The microbiota exerts diverse physiological functions to include: growth inhibition of pathogenic microorganisms, synthesis of compounds useful for the trophism of colonic mucosa, regulation of intestinal lymphoid tissue and synthesis of amino acids. Furthermore, mucus seems to play an important role in protecting the intestinal mucosa and maintaining its integrity. Changes in the microbiota composition are mainly influenced by diet and age, as well as genetic factors. Increasing evidence indicates that dysbiosis favors the production of genotoxins and metabolites associated with carcinogenesis and induces dysregulation of the immune response which promotes and sustains inflammation in IBD leading to carcinogenesis. A disequilibrium in gut microflora composition leads to the specific activation of gut associated lymphoid tissue. The associated chronic inflammatory process associated increases the risk of developing CRC. Ulcerative colitis and Crohn’s disease are the two major IBDs characterized by an early onset and extraintestinal manifestations, such as rheumatoid arthritis. The pathogenesis of both diseases is complex and not yet fully known. However, it is widely accepted that an inappropriate immune response to microbial flora can play a pivotal role in IBD pathogenesis.     

肠道微生物群在糖尿病肾病中作用及治疗

目的：综述肠道微生物代谢产物短链脂肪酸理论、胆汁酸、内毒素在DKD中作用及治疗。方法：通过查阅国内外文献,论述肠道微生物代谢产物短链脂肪酸理论、胆汁酸、内毒素与DKD关系,阐述肠道微生物系统在DKD治疗中的影响,强调DKD早期、中晚期其代谢产物通过不同的路径作用,基于此提出DKD最新治疗方式。结果：肠道微生物群通过短链脂肪酸轴、胆汁酸轴、内毒素轴对DKD不同时期影响胰岛素分泌及炎症反应,最新治疗均与肠道微生物相关。结论：肠道微生物通过一系列代谢产物,因此通过影响其代谢产物途径多靶点作用,防止或延缓DKD进展。     

Gut microbiota in common elderly diseases affecting activities of daily living

Gut microbiota are involved in the development or prevention of various diseases such as type 2 diabetes,fatty liver, and malignancy such as colorectal cancer,breast cancer and hepatocellular carcinoma. Alzheimer'sdisease, osteoporosis, sarcopenia, atherosclerotic stroke and cardiovascular disease are major diseases associated with decreased activities of daily living(ADL), especially in elderly people. Recent analyses have revealed the importance of gut microbiota in the control of these diseases. The composition or diversity of these microbiota is different between patients with these conditions and healthy controls, and administration of probiotics or prebiotics has been shown effective in the treatment of these diseases. Gut microbiota may affect distant organs through mechanisms that include regulating the absorption of nutrients and/or the production of microbial metabolites, regulating and interacting with the systemic immune system, and translocating bacteria/bacterial products through disrupted mucosal barriers.Thus, the gut microbiota may be important regulators in the development of diseases that affect ADL. Although adequate exercise and proper diet are important for preventing these diseases, their combination with interventions that manipulate the composition and/or diversity of gut microbiota could be a promising strategy for maintaining health condition and preserving ADL. This review thus summarizes current understanding of the role of gut microbiota in the development or prevention of diseases closely associated with the maintenance of ADL.     

Diet and Gut Microbial Function in Metabolic and Cardiovascular Disease Risk

Over the past decade, the gut microbiome has emerged as a novel and largely unexplored source of variability for metabolic and cardiovascular disease risk, including diabetes. Animal and human studies support several possible pathways through which the gut microbiome may impact health, including the production of health-related metabolites from dietary sources. Diet is considered important to shaping the gut microbiota; in addition, gut microbiota influence the metabolism of many dietary components. In the present paper, we address the distinction between compositional and functional analysis of the gut microbiota. We focus on literature that highlights the value of moving beyond surveys of microbial composition to measuring gut microbial functioning to delineate mechanisms related to the interplay between diet and gut microbiota in cardiometabolic health.     

Bacteria-related changes in host DNA methylation and the risk for CRC

SUMMARY

Colorectal cancer (CRC) is the second most common cause of cancer deaths in men and women combined. Colon-tumor growth is multistage and the result of the accumulation of spontaneous mutations and epigenetic events that silence tumor-suppressor genes and activate oncogenes. Environmental factors are primary contributors to these somatic gene alterations, which account for the increase in incidence of CRC in western countries. In recent decades, gut microbiota and their metabolites have been recognized as essential contributing factors to CRC, and now serve as biomarkers for the diagnosis and prognosis of CRC. In the present review, we highlight holistic approaches to understanding how gut microbiota contributes to CRC. We particularly focus herein on bacteria-related changes in host DNA methylation and the risk for CRC.     

Mechanisms of gut microbiota-mediated bone remodeling

The mechanisms underlying the systemic effects mediated by gut microbiota are under active investigation. In addition to local, direct effects of gut microbiota on the host, metabolic products from microbiota may act peripherally, reaching distal organs through the circulation. In our recent publication we demonstrated that gut microbiota influence bone remodeling distally, promoting both bone resorption and formation. We proposed that these effects are mediated, at least in part, by the induction of insulin like growth factor (IGF-1) by the microbiota metabolite short chain fatty acids (SCFA). Here we explore additional mechanisms by which microbial metabolites could directly or indirectly alter host bone remodeling. We discuss whether SCFA directly modulate bone resorption by their actions on osteoclasts, and test the possibility that serotonin is another gut microbiota derived long-distance mediator of effects on bone remodeling. A detailed understanding of the mechanisms of microbiota effect on bone remodeling could help establish potential therapeutic strategies to promote bone health.     

Gut microbiota and metabolic syndrome

Symbiosis is the result of the relationship between gut microbiota and human surfaces; in fact, it regulates many functions such as metabolic and protective ones. It is widely known that any changes in the microbes in gut microbiota (dysbiosis) and the regulation of mucosal and systemic host’s immunity have been linked to different diseases such as metabolic syndromes and associated disorders. Recent studies report an aberrant gut microbiota and an alteration of gut microbial metabolic activities in obese subjects, with an important influence of a number of human physiological functions. Most studies suggest that diet, especially the high-fat low-fiber western-style diet, dramatically impacts on gut microbiota composition and functions in those patients with metabolic syndrome. A deeper knowledge of a specific microbiota profile associated with increased risk of metabolic disease and its subsequent modification induced by prebiotics, probiotics or targeted antibiotics will be necessary for the development of new therapeutic approaches in the treatment of metabolic disease.