Altered microbiomes distinguish Alzheimer’s disease from amnestic mild cognitive impairment and health in a Chinese cohort

Fecal Microbiota Transplantation in Neurological Disorders

“…In recent years, numerous publications on the relation between AD and the gut microbiota have become available. AD patients have a different gut microbiota composition compared to healthy controls or elderly without dementia (Vogt et al, 2017;Zhuang et al, 2018;Haran et al, 2019;Li B. et al, 2019;Liu et al, 2019), but α-diversity measures show contrasting results (Vogt et al, 2017;Li B. et al, 2019;Liu et al, 2019;Saji et al, 2019). Hypotheses on the role of the gut microbiota include direct actions of bacteria, indirect actions or aging-related processes (Angelucci et al, 2019).…”

“…Several studies suggest an important role of the gut microbiota in the pathophysiology of neurological disorders. A different human gut microbiota composition compared to healthy controls has been reported for several neurological disorders, such as Parkinson's disease (Hasegawa et al, 2015;Keshavarzian et al, 2015;Scheperjans et al, 2015;Unger et al, 2016), multiple sclerosis (Miyake et al, 2015;Chen et al, 2016;Jangi et al, 2016;Cosorich et al, 2017), autism spectrum disorder (Finegold et al, 2002(Finegold et al, , 2010De Angelis et al, 2013Kang et al, 2013;Ma et al, 2019), Alzheimer's disease (Vogt et al, 2017;Zhuang et al, 2018;Haran et al, 2019;Li B. et al, 2019;Liu et al, 2019), neuromyelitis optica (Cree et al, 2016), Rett syndrome (Strati et al, 2016), epilepsy (Xie et al, 2017;Peng et al, 2018;Lindefeldt et al, 2019), amyotrophic lateral sclerosis (Fang et al, 2016;Rowin et al, 2017;Mazzini et al, 2018), cerebral infarction (Karlsson et al, 2012;Yin et al, 2015), spinal cord injury (Gungor et al, 2016), and multiple system atrophy (Tan et al, 2018). However, data on microbiota composition are frequently inconsistent and numerous potential confounders are involved.…”

Dysregulated Gut Homeostasis Observed Prior to the Accumulation of the Brain Amyloid-β in Tg2576 Mice

“…Loss of bacterial diversity, a commonly used marker of dysbiosis (defined as shift in gut microbiome composition that is accompanied by disease-like events [48]) is associated with multiple diseases such as inflammatory bowel disease (IBD) [49], obesity and metabolic syndrome [50], and hospital-acquired pseudomembranous colitis [51]. Loss of gut microbiota diversity has been reported in AD patients [52,53]. Our data showed a significantly reduced alpha-(within-sample) diversity as well as a significantly different beta-(between-sample) diversity at the symptomatic timepoint, which were not present pre-symptomatically, when compared to age-matched controls.…”

The Links Between the Gut Microbiome, Aging, Modern Lifestyle and Alzheimer's Disease

“…There is data indicating that melatonin and the circadian rhythms regulate the intestinal microbial flora (Zhu et al, 2018;Parkar et al, 2019), and that circadian rhythm disruption by abnormal light-dark (LD) cycles results in the dysfunction of the intestinal barrier and increases the number Ruminococcus torques but reduces that of Lactobacillus johnsonii (Deaver et al, 2018). In addition, circadian disruption affects functional gene composition of gut microbiome leading to downregulation of the genes involved in promoting host beneficial immune responses and upregulation of the genes involved in the synthesis and transportation of lipopolysaccharides (LPS) (Deaver et al, 2018), which is similar to the changes of the functional composition of the gut microbiome in AD patients (Liu et al, 2019a).…”

“…Irrespective of bacterial taxa, the functional composition of the gut microbiota may also be important (Lozupone et al, 2012). In this regards, Liu et al conducted function analysis of microbiome in AD patients, patients with amnestic mild cognitive impairment (aMCI) and healthy controls (HC) based on Kyoto Encyclopedia of Genes and Genomes (KEGG) functional pathway (Liu et al, 2019a). They identified 5 altered functional orthologs in AD patients using level 3 KEGG pathways.…”