To investigate the changes of intestinal flora and serum amino acid levels in elderly patients with Parkinson's disease(PD)at different stages, and to provide evidence for diagnosis, prevention and treatment of PD.

A total of 140 elderly PD patients diagnosed and treated in our hospital from January 2018 to August 2019 were enrolled and divided into PD course <5 years group(n=70)and PD course≥5 years group(n=70). Ninety subjects without PD confirmed by medical examination in our hospital were included as the control group.Real-time fluorescence quantitative PCR of 16S rDNA gene was used to detect levels of Bifidobacterium, Lactobacillus, Clostridium prasus, Enterococcus, Enterobacter, Prevotella copri and Akkermansia muciniphila bacteria in the gut, and the high-performance liquid chromatography was used to detect the serum amino acids in the three groups.

Compared with the control group, the levels of Bifidobacterium, Lactobacillus, Clostridium prasalis and Prevotella copri in the intestines were decreased and Enterobacter level was increased in PD course <5 years group and PD course≥5 year group( F=20.863, 32.251, 23.166, 24.683 and 10.136, all P<0.001). The serum levels of methionine, tryptophan, lysine and glutamate in PD course <5 years and PD course≥5 year group were decreased as compared with the control group(F=5.858, 5.877, 4.183 and 25.462, all P<0.05). Spearman correlation analysis showed that serum glutamate level was positively correlated withClostridium prastia in the intestine(r=0.647, P=0.002)and negatively correlated with Prevotella copri(r=-0.559, P=0.010). Multivariate Logistic regression analysis showed that the protective factors in the intestines of elderly PD patients were Bifidobacterium(OR=0.186, 95%CI: 0.054-0.637, P=0.007), Lactobacillus(OR=0.283, 95%CI: 0.098-0.816, P=0.020), Clostridium prastia(OR=0.232, 95%CI: 0.063-0.851, P=0.028), and Prevotella copri(OR=0.222, 95%CI: 0.058-0.851, P=0.028), and the risk factor was Enterobacter(OR=5.119, 95%CI: 1.406-18.636, P=0.013).

The decreases of Bifidobacterium, Lactobacillus, Clostridium, Prevotella copri and Enterobacter levels in the intestinal tract of PD patients, and the decrease of serum glutamate level may be correlated to the progression of PD.

Parkinson disease; Intestinal flora; Amino acids