====== Gut microbiome ====== {{ ::gut-flora.jpg?400|}} The [[gut]] [[microbiome]] refers to the collection of microorganisms, including bacteria, viruses, fungi, and other microbes, that live in the human [[gastrointestinal tract]]. These microorganisms play important roles in maintaining digestive health, modulating the immune system, and producing certain nutrients. The gut microbiome has also been linked to a variety of health conditions, including obesity, inflammatory bowel disease, and even neurological disorders such as depression and autism. Research in this area is ongoing, and scientists are working to better understand the complex interactions between the gut microbiome and human health. ---- ---- Accumulating evidence has indicated that intestinal [[microbiota]] is involved in the development of various human [[disease]]s, including [[cardiovascular]] [[disease]]s (CVDs). Both human and animal [[experiment]]s have revealed that alterations in the composition and function of intestinal [[flora]], recognized as gut microflora dysbiosis, can accelerate the progression of CVDs. Moreover, intestinal flora metabolizes the [[diet]] ingested by the [[host]] into a series of [[metabolite]]s, including [[trimethylamine]] N-oxide, short chain [[fatty acid]]s, secondary bile acid and indoxyl sulfate, which affects the host physiological processes by activation of numerous [[signalling pathway]]s. The aim of a review was to summarize the role of gut microbiota in the pathogenesis of CVDs, including coronary artery disease, hypertension and heart failure, which may provide valuable insights into potential therapeutic strategies for CVD that involve interfering with the composition, function and metabolites of the intestinal flora ((Jin M, Qian Z, Yin J, Xu W, Zhou X. The role of intestinal microbiota in cardiovascular disease. J Cell Mol Med. 2019 Feb 3. doi: 10.1111/jcmm.14195. [Epub ahead of print] Review. PubMed PMID: 30712327. )). ---- Xu et al., explored the role of the intestinal microbiota on oxidative stress and autophagy in stroke, and Astragaloside IV (AS-IV) reversed the changes induced by intestinal microbiota. We determined the characteristics of the intestinal microbiota of AIS and transient ischaemic attack (TIA) patients by 16S sequencing and found that the structure and diversity of the intestinal microbiota in patients with AIS and TIA were significantly different from those in healthy subjects. Specifically, the abundance of genus Bifidobacterium, Megamonas, Blautia, Holdemanella, and Clostridium, content of homocysteine and triglyceride was increased significantly, thus it may be as a potential mechanism of AIS and TIA. Furthermore, germ-free mice were infused intracolonically with fecal supernatants of TIA and AIS with/without feed AS-IV for 12 weeks, and we found that the feces of AIS up-regulated the autophagy markers Beclin-1, light chain 3 (LC3)-II and autophagy-related gene (Atg)12, and the expression of reactive oxygen species (ROS) and NADPH oxidase 2/4 (NOX2/4), malondialdehyde (MDA), however, the expression of total antioxidant capacity (T-AOC) and activity of superoxide dismutase (SOD) and glutathione (GSH) was down-regulated in brain tissue, the content of homocysteine and free fatty acids (FFA) in serum of the mice. Meanwhile, AS-IV could reverse the above phenomenon, however, it does not affect the motor function of mice. AS-IV reversed these changes and it may be a potential drug for AIS therapeutics ((Xu N, Kan P, Yao X, Yang P, Wang J, Xiang L, Zhu Y. Astragaloside IV reversed the autophagy and oxidative stress induced by the intestinal microbiota of AIS in mice. J Microbiol. 2018 Nov;56(11):838-846. doi: 10.1007/s12275-018-8327-5. Epub 2018 Oct 24. PubMed PMID: 30353470. )). ---- The gut [[microbiota]] has recently gained attention as a possible modulator of [[brain activity]]. A number of reports suggest that the [[microbiota]] may be associated with neuropsychiatric conditions such as [[major depressive disorder]], [[autism]], and [[anxiety]]. The [[gut]] microbiota is thought to influence the brain via [[vagus nerve]] signaling, among other possible mechanisms. The [[insula]] processes and integrates these vagal signals. To determine if microbiota diversity and structure modulate brain activity. Curtis et al., collected [[fecal]] samples and examined insular function using [[resting state]] [[functional connectivity]] (RSFC). Thirty healthy participants (non-smokers, tobacco smokers, and electronic cigarette users, n=10 each) were studied. They found that the RSFC between the insula and several regions ([[frontal pole]] left, lateral occipital cortex right, [[lingual gyrus]] right, and [[cerebellum]] and vermis) were associated with bacterial microbiota diversity and structure. In addition, two specific bacteria genera, [[Prevotella]] and [[Bacteroides]], were specifically different in [[tobacco]] smokers and also associated with insular connectivity. In conclusion, they showed that insular connectivity is associated with [[microbiome]] diversity, structure, and at least two specific bateria genera. Furthemore, this association is potentially modulated by tobacco smoking, although the sample sizes for the different smoking groups were small and this result needs validation in a larger cohort. While replication is necessary, the microbiota is a readily accesible therapeutic target for modulating insular connectivity, which has previously been shown to be abnormal in [[anxiety]] and [[tobacco]] use [[disorder]]s ((Curtis K, Stewart CJ, Robinson M, Molfese DL, Gosnell SN, Kosten TR, Petrosino JF, De La Garza R II, Salas R. Insular Resting State Functional Connectivity is Associated with Gut Microbiota Diversity. Eur J Neurosci. 2018 Dec 16. doi: 10.1111/ejn.14305. [Epub ahead of print] PubMed PMID: 30554441. )). ===== Gut Microbiome and Cerebral Vasospasm ===== [[Gut Microbiome and Cerebral Vasospasm]] ===== References =====