Characteristics of gut microbiota and its response to a Chinese Herbal Formula in elder patients with metabolic syndrome

Alterations in gut microbiota have been known to play a critical role in metabolic syndrome. However, the microbial features in elderly patients with metabolic syndrome remain unclear. A traditional Chinese Herbal Formula, Yangyin Tiluo Decoction (YTD), can alleviate metabolic syndrome and cardiovascular disease. To characterize gut microbiota in elder patients and effects of YTD on gut microbiota during treatment of metabolic syndrome, 11 healthy elderly persons and 12 elderly persons (aged 60-90 years) with metabolic syndrome were enrolled. The patients were randomly assigned to receive YTD for 4 weeks (200 mL of the decoction two times daily). The microbial composition in healthy control, pre- and post-YTD treatment group were analyzed by 16S rRNA sequencing of fecal DNAs. Biochemical measurements were conducted for elderly patients. The results showed a high inter-individual variation of gut microbiota in elderly persons. The gut microbiota was dominated by phylum Firmicutes and Actinobacteria, which was distinct from the previously defined microbiota in Irish elderly persons. The elderly patients with metabolic syndrome had higher proportions of Lactobacillus and Bifidobacterium, and lower proportions of Anaerostipes, Coprococcus, Ruminococcus than healthy controls. YTD treatment reduced the abundance of genus Bacteroidales Incertae Sedis and species Enterobacteriaceae Incertae Sedis. The concentration of plasma lipoprotein (a) was also reduced, which was negatively correlated with the abundance of an Acinetobacter species. These results reveal a remarkable dominance of Firmicutes and Actinobacteria, and highlight the distinct gut microbiota in elderly patients with metabolic syndrome, which may be involved in pathogenesis. Furthermore, the benefits of YTD treatment were observed, providing an approach to improve metabolic syndrome in elderly patients.