Department of Genetics, Physiology and Microbiology (Animal Physiology Unit), School of Biology, Complutense University of Madrid. Institute of Investigation of Hospital 12 de Octubre (i+12), Madrid, Spain.
J Alzheimers Dis. 2021;81(4):1345-1360. doi: 10.3233/JAD-201587.
Trillions of commensal microbes live in our body, the majority in the gut. This gut microbiota is in constant interaction with the homeostatic systems, the nervous, immune and endocrine systems, being fundamental for their appropriate development and function as well as for the neuroimmunoendocrine communication. The health state of an individual is understood in the frame of this communication, in which the microbiota-gut-brain axis is a relevant example. This bidirectional axis is constituted in early age and is affected by many environmental and lifestyle factors such as diet and stress, among others, being involved in the adequate maintenance of homeostasis and consequently in the health of each subject and in his/her rate of aging. For this, an alteration of gut microbiota, as occurs in a dysbiosis, and the associated gut barrier deterioration and the inflammatory state, affecting the function of immune, endocrine and nervous systems, in gut and in all the locations, is in the base of a great number of pathologies as those that involve alterations in the brain functions. There is an age-related deterioration of microbiota and the homeostatic systems due to oxi-inflamm-aging, and thus the risk of aging associated pathologies such as the neurodegenerative illness. Currently, this microbiota-gut-brain axis has been considered to have a relevant role in the pathogenesis of Alzheimer's disease and represents an important target in the prevention and slowdown of the development of this pathology. In this context, the use of probiotics seems to be a promising help.
数以万亿计的共生微生物生活在我们的体内，其中大部分存在于肠道中。这些肠道微生物群与内稳态系统（包括神经系统、免疫系统和内分泌系统）不断相互作用，对其适当的发育和功能以及神经免疫内分泌通讯至关重要。个体的健康状态就是在这种通讯的框架内理解的，其中微生物群-肠道-大脑轴是一个重要的例子。这个双向轴在早期形成，并受到许多环境和生活方式因素的影响，如饮食和压力等，参与维持内稳态的适当性，从而影响每个个体的健康和衰老速度。为此，肠道微生物群的改变，如发生在肠道菌群失调时，以及相关的肠道屏障恶化和炎症状态，会影响免疫、内分泌和神经系统的功能，无论是在肠道还是在所有部位，都与许多疾病有关，如涉及大脑功能改变的疾病。由于氧化-炎症-衰老，微生物群和内稳态系统会随着年龄的增长而恶化，因此与衰老相关的疾病（如神经退行性疾病）的风险也会增加。目前，这个微生物群-肠道-大脑轴被认为在阿尔茨海默病的发病机制中具有重要作用，并且是预防和减缓这种病理发展的一个重要靶点。在这种情况下，使用益生菌似乎是一种很有前途的帮助。
