肠道菌群对结直肠癌发生、发展和诊疗影响的研究进展

结直肠癌是全球三大恶性肿瘤之一,具有高发病率和高死亡率。肠道菌群失调会引发一系列疾病包括肠道肿瘤。大量研究结果表明结直肠癌的发生、发展和诊疗与肠道菌群密切相关。本文就肠道菌群在结直肠癌发生、发展中的作用以及益生菌在结直肠癌诊断和治疗中的应用作一综述。     

肠道菌群在结直肠癌发病与治疗中的研究进展

结直肠癌是常见的消化道恶性肿瘤.近年来有关肠道菌群的研究结果显示,肠道菌群结构、丰度和功能的改变与很多疾病密切相关,如炎症性肠病、自身免疫性疾病、消化道肿瘤等.肠道菌群失调可通过菌群移位、"驱动-乘客"模型、"毒性"肠道细菌模型等机制导致结直肠癌的发生发展.而补充膳食纤维与益生菌,应用肠道微生物移植技术可通过抑制肿瘤血...     

肠道菌群在结直肠癌发生发展的机制研究

目的 结直肠癌已经成为了世界上最常见的致命癌症之一。近年来的研究结果显示肠道微生物群失衡与结直肠癌(CRC)之间密切相关。本文综述了肠道微生物群在结直肠癌中的相关机制,通过一些突出的微生物如pks+大肠杆菌、产肠毒素脆弱拟杆菌(ETBF)、核梭杆菌(F.nucleatum)、粪球杆菌来讨论肠道微生物活动与致癌作用联系起来的具体机制如DNA损伤、炎症、免疫、氧化应激、代谢物调节等,对未来肠道微生物群临床干预结直肠癌的发生发展有着积极的影响。     

益生菌与结直肠癌发病的关系

肠道菌群与人体健康有密切联系,炎症性肠病、结直肠癌等均与肠道菌群失调有关。摄入益生菌制剂是调节肠道菌群及其功能较为常用的方法。研究表明补充益生菌可能通过调节肠道黏膜免疫和炎症、抑制致病菌定植和繁殖、修复肠上皮屏障功能、抑制肿瘤细胞增殖、抑制致癌化学物活性以及抗氧化作用等．对结直肠肿瘤产生一定预防和治疗作用。本文就益生菌与结直肠癌发病的关系作一综述。     

炎症性肠病发病机制及治疗的研究进展

炎症性肠病(IBD)是一种肠道的特发性、慢性和复发性炎性疾病,其发病机制非常复杂,受到遗传、环境和微生物因素之间相互作用的影响,目前生物制剂治疗存在诸多缺陷。结直肠慢性炎性反应是结直肠癌发生发展的关键因素,IBD与结直肠癌高度相关,早期防治IBD对于预防癌变具有重要意义。     

肠道菌群失调对结直肠癌发生的影响

结直肠癌是世界常见的肿瘤之一，其发病率有逐年增长趋势，对人类健康危害很大。目前，大量研究表明肠道菌群失调在结直肠癌发生中可能起到重要作用。肠道菌群失调可通过引起肠道上皮细胞基因改变、肠道炎症反应、肠道微环境紊乱等机制促使肿瘤发生。诸多研究发现一部分特定微生物如球形梭菌、牛链球菌生物型Ⅰ型、产肠毒素脆弱拟杆菌、侵袭性大肠杆菌、人乳头状瘤病毒等在结直肠癌的发生中可能起到非常重要的作用。本文就肠道菌群在结直肠癌发生中的影响及具体机制进行综述。     

肠道菌群及防御素在结直肠癌发病中的作用

结直肠癌是消化系常见的恶性肿瘤之一.近年来,我国结直肠癌的发病率和死亡率呈持续上升趋势,造成沉重的医疗负担,但其确切病因仍然未知.因此,推进结直肠癌病因和发病机制的相关研究,进而开展早期预防,有效筛查和靶向治疗是一项迫切的医学任务.目前,肠道菌群与结直肠癌的相关性研究不断深入,而防御素(defensin)作为肠道菌群与肠道黏膜相互作用的介质之一,其在结直肠癌发生发展中的潜在地位也逐渐引起关注.本文对人体肠道菌群及防御素进行了简要介绍,并对二者在结直肠癌发病中的作用及其可能机制相关研究进展进行了回顾,另外还初步探索了二者之间的相互影响作用.     

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。     

肠道菌群在结直肠癌中的研究进展

人体肠道菌群是一个复杂的系统,由大量的微生物构成.肠道菌群和人类健康与疾病密切相关,且始终保持着动态平衡.肠道菌群之间相互作用,同时与机体共同维持消化,吸收,代谢等功能.近年来,肠道菌群始终是研究的一大热点,有大量研究表明肠道菌群与结直肠癌的发生发展密切相关.本文就肠道菌群与结直肠癌的关系,发病机制及防治作用进行综述,为结直肠癌的研究提供一些新思路.     

肠道微生态在大肠癌精准治疗中作用的研究进展

近年来,肠道微生态在疾病中的作用日益得到关注,尤其是在作为肠道微生态载体的结直肠(大肠)中的研究,更是取得了一定进展,肠道微生态在结直肠癌(colorectal cancer,C R C)发生、发展过程中的作用逐步被阐明.越来越多的研究表明肠道微生态在临床已取得一定疗效的CRC相关精准治疗方式如肿瘤免疫疗法、肿瘤化学疗法、肿瘤益生菌干预等方法中发挥关键作用,其机制仍有待进一步探索.本文就CRC中与微生态相关的精准治疗方式及其潜在机制进行简要综述.     

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。     

Effect of probiotic administration on the intestinal microbiota,current knowledge and potential applications

Although it is now known that the human body is colonized by a wide variety of microbial populations in different parts(such as the mouth, pharynx and respiratory system, the skin, the gastro- and urogenital tracts), many effects of the complex interactions between the human host and microbial symbionts are still not completely understood. The dysbiosis of the gastrointestinal tract microbiota is considered to be one of the most important contributing factors in the development of many gastrointestinal diseases such as inflammatory bowel disease, irritable bowel syndrome and colorectal cancer, as well as systemic diseases like obesity, diabetes, atherosclerosis and non-alcoholic fatty liver disease. Fecal microbial transplantations appear to be promising therapies for dysbiosis-associated diseases; however, probiotic microorganisms have been growing in popularity due to increasing numbers of studies proving that certain strains present health promoting properties, among them the beneficial balance of the intestinal microbiota. Inflammatory bowel diseases andobesity are the pathologies in which there are more studies showing this beneficial association using animal models and even in human clinical trials.In this review,the association of the human gut microbiota and human health will be discussed along with the benefits that probiotics can confer on this symbiotic activity and on the prevention or treatment of associated diseases.     

Microbial-gut interactions in health and disease. Irritable bowel syndrome

The intestinal microbiota interacts with several aspects of gastrointestinal function that may affect the expression or progression of disease. For example, a role for bacterial metabolism of bile acids and food has been linked to colorectal cancer development. Studies have also shown a potential role of the intestinal microbiota in the modulation of inflammation in the intestine and joints. Normal gut physiology is molded by the interaction between the intestinal microbiota and the host's gastrointestinal tissues, including motility, absorption and secretion, and intestinal permeability. Early studies in axenic mice demonstrated gross morphological abnormalities and gut motor dysfunction related to the absence of a normal microflora, raising the possibility that shifts in commensal bacterial populations could play a role in the development of altered motility states including functional disorders of the gut. This chapter concentrates on the experimental evidence for a role of intestinal microbiota and the potential therapeutic value of probiotics in functional diseases such as irritable bowel syndrome.     

肠道菌群与疾病关系的研究进展

多种疾病与肠道菌群失衡有关。肠道微生物参与宿主新陈代谢和免疫系统的调节,并与环境因子相互作用决定机体的健康和疾病状态。本文就肠道菌群与代谢综合征、炎症性肠病和结直肠癌等疾病关系的研究进展作一综述,进一步揭示了肠道微生物在人类健康中起到的重要作用,并通过介绍益生菌和粪菌移植等方法,为探索治疗诸多疾病提供新的方向。     

Therapeutic methods of gut microbiota modification in colorectal cancer management – fecal microbiota transplantation,prebiotics, probiotics,and synbiotics

ABSTRACT

The link between gut microbiota and the development of colorectal cancer has been investigated. An imbalance in the gut microbiota promotes the progress of colorectal carcinogenesis via multiple mechanisms, including inflammation, activation of carcinogens, and tumorigenic pathways as well as damaging host DNA. Several therapeutic methods are available with which to alter the composition and the activity of gut microbiota, such as administration of prebiotics, probiotics, and synbiotics; these can confer various benefits for colorectal cancer patients. Nowadays, fecal microbiota transplantation is the most modern way of modulating the gut microbiota. Even though data regarding fecal microbiota transplantation in colorectal cancer patients are still rather limited, it has been approved as a clinical method of treatment-recurrent Clostridium difficile infection, which may also occur in these patients. The major benefits of fecal microbiota transplantation include modulation of immunotherapy efficacy, amelioration of bile acid metabolism, and restoration of intestinal microbial diversity. Nonetheless, more studies are needed to assess the long-term effects of fecal microbiota transplantation. In this review, the impact of gut microbiota on the efficiency of anti-cancer therapy and colorectal cancer patients’ overall survival is also discussed.     

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.     

Emerging roles of lactic acid bacteria in protection against colorectal cancer

Colorectal cancer(CRC)is the third leading cause of cancer deaths worldwide and the fourth most common cancer diagnosed among men and women in the United States.Considering the risk factors of CRC,dietary therapy has become one of the most effective approaches in reducing CRC morbidity and mortality.The use of probiotics is increasing in popularity for both the prevention and treatment of a variety of diseases.As the most common types of microbes used as probiotics,lactic acid bacteria(LAB)are comprised of an ecologically diverse group of microorganisms united by formation of lactic acid as the primary metabolite of sugar metabolism.LAB have been successfully used in managing diarrhea,food allergies,and inflammatory bowel disease.LAB also demonstrated a host of properties in preventing colorectal cancer development by inhibiting initiation or progression through multiple pathways.In this review,we discuss recent insights into cellular and molecular mechanisms of LAB in CRC prevention including apoptosis,antioxidant DNA damages,immune responses,and epigenetics.The emerging experimental findings from clinical trials as well as the proposed mechanisms of gut microbiota in carcinogenesis will also be briefly discussed.     

肠道微生物、表观遗传修饰与肿瘤防治的研究进展

肠道微生物是人体最庞大、最复杂的微生态系统,在调节人体健康方面发挥着重要作用。肠道微生物可以调控相关信号通路及表观遗传修饰,进而在促进或抑制多种肿瘤的生长、扩散和转移中发挥重要作用。本文以肠道微生物为出发点,综述了粪菌移植和益生菌2种直接调控肠道微生物的方式,以及肠道微生物对表观遗传修饰的影响,为肿瘤防治提供新的策略。     

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.