Table 5 Microbial therapies for PD

Probiotics

[263]

Probiotics treatment: 25

Placebo: 25

Lactobacillus acidophilus, Bifidobacterium bifidum, L. reuteri, and L. fermentum

12 weeks

Downregulated the gene expression of IL-1, IL-8, and TNF-α and upregulated TGF-β and PPAR-γ in PBMC

[264]

Probiotics treatment: 30

Placebo: 30

L. acidophilus, B. bifidum, L. reuteri, and L. fermentum

12 weeks

Decreased MDS-UPDRS, hs-CRP, and malondialdehyde, enhanced glutathione, and improved insulin sensitivity

[265]

Probiotics treatment: 34

Placebo: 38

L. acidophilus, L. reuteri, L. gasseri, L. rhamnosus, B. bifidum, B. longum, Enterococcus faecalis, E. faecium

4 weeks

Improved constipation symptoms

[266]

Probiotics treatment: 23

Placebo: 23

Bacillus licheniformis, L. acidophilus, B. longum, E. faecalis

12 weeks

Improved constipation symptoms and positively affected gut microbiota

Prebiotics

[267]

PD: 19

A diet rich in insoluble fiber

2 months

Improved constipation symptoms and increased plasma levodopa bioavailability and motor function

[268]

Resistant starch: 32 PD, 30 control

Solely dietary instructions: 25 PD

Resistant starch

8 weeks

Improved nonmotor symptom scores, increased fecal butyrate, and decreased fecal calprotectin levels

[191]

Newly diagnosed, non-medicated PD: 10

Treated PD: 10

Prebiotic fiber

10 days

Prebiotic intervention was well tolerated and safe, associated with beneficial biological changes in microbiota, SCFA, inflammation, and neurofilament light chain, and may improve clinical symptoms (i.e., gastrointestinal symptoms and UPDRS)

Synbiotics

[269]

Multiple probiotic strains and prebiotic fiber: 80

Placebo: 40

Multiple probiotic strains: Streptococcus salivarius subsp. thermophilus, E. faecium, L. rhamnosus GG, L. acidophilus, L. plantarum, L. paracasei, L. delbrueckii subsp. bulgaricus, and Bifidobacterium

Prebiotic fiber: fructo-oligosaccharides

4 weeks

Improved constipation symptoms

[270]

Multi-strain probiotic (Hexbio®): 22

Placebo: 26

Multi-strain probiotic (Lactobacillus sp. and Bifidobacterium sp.) with fructo-oligosaccaride

8 weeks

Improved bowel opening frequency and whole gut transit time

Fecal microbiota transplantation

[271]

PD: 15

Purified fecal microbiota suspension

Once

Relieved motor and nonmotor symptoms with acceptable safety

[272]

PD: 6

Fecal suspension

Once

Relieved motor and nonmotor symptoms, including constipation

[273]

PD: 11

Frozen fecal microbiota

Once

Reconstructed gut microbiota and improved motor and nonmotor symptoms

[274]

PD: 12

FMT capsules (n = 8)

placebo (n = 4)

Twice weekly for 12 weeks

Improved subjective motor and non-motor complaints, intestinal microbiota diversity, gut transit, and motility