Dysregulation of Ruminococcaceae and Megamonas could be predictive markers for rapid progression of mild cognitive impairment

Intestinal flora dysregulation may affect the development of Alzheimer's disease (AD). However, the correlation between intestinal flora and rapid progression of mild cognitive impairment (MCI) is rarely reported. Our aim was to investigate the features of the intestinal flora in patients with rapidly progressive MCI. A total of 1013 participants were screened, in which 87 patients with MCI were followed up for two years. At the baseline time point, fecal samples of the patients were sequenced via the microbial diversity high-throughput 16 s-rDNA. After a two-year follow-up, 30 patients with MCI presented rapidly progressive cognitive impairment, whereas the 57 patients remained unprogressive. Analyses of their fecal samples showed that the abundance of 11 intestinal microflora were significantly different between the two groups at the baseline time point. Further analyses revealed that the decrease of Ruminococcaceae abundance and the increase of Megamonas abundance were significantly correlated with the progression of MCI. Also, the decreased Ruminococcaceae was independently associated with several factors such as P-tau181, and the increased Megamonas was independently associated with diabetes, low-density lipoprotein, median cell count. The decrease of Ruminococcaceae and the increase of Megamonas could act as predictive markers for the rapidly progressive MCI.