In vitro evidence suggests probiotics may decrease pro-inflammatory cytokines, oxidative stress, and potentially pathogenic bacterial overgrowth in patients with Parkinson disease
(PD), according to a study in Frontiers in Immunology
. The study was conducted to investigate whether the use of probiotics could benefit patients with PD.
“Despite the great interest that recently arose around the gut-brain axis in health and disease, our study is the first to specifically address the effect of probiotics on mediators of inflammation and oxidative damage in peripheral blood mononuclear cells (PBMCs) of PD patients,” researchers wrote.
A total of 80 participants were enrolled for the study. Half of the participants were patients with PD while the other half were age-matched healthy donors recruited for the study’s control group. The PD group included 15 women and 25 men with a mean age of 70 years while the control group included 18 women and 22 men with a mean age of 68 years. Patients were followed-up regularly at the Movement Disorder Center of Maggiore Hospital in Novara, Italy.
Researchers drew 20 mL of blood, which was stored in vacuum tubes that contained heparin, from participants during clinical assessments. The samples were collected at the same time each visit to avoid confounding factors caused by circadian rhythm. Human PBMCs were isolated from heparinized blood from participants in both groups.
Researchers isolated and co-cultured PBMCs with a selection of probiotics microorganisms belonging to the lactobacillus
genus. The 6 probiotic strains used in the study were Lactobacillus salivarius
, Lactobacillus plantarum
, Lactobacillus acidophilus
, Lactobacillus rhamnosus
, Bifidobacterium animalis
, and Bifidobacterium breve
An enzyme-linked immunoassay kit was used to investigate in vitro release of major pro-inflammatory cytokines, tumor necrosis factor-α and interleukin (IL)-17A, and anti-inflammatory cytokines, IL-4 and IL-10, by PBMCs, as well as the production of reactive oxygen species (ROS). Researchers also assessed the ability of probiotics to influence membrane integrity, antagonize the growth of potential pathogen bacteria, such as Escherichia coli
and Klebsiella pneumoniae
, and encode tyrosine decarboxylase
Researchers found that all probiotic strains inhibited inflammatory cytokines and ROS production in both groups. Out of all their findings, they acknowledged the most striking was that bacterial strains L salivarius
and L acidophilus
significantly reduced pro-inflammatory and increased anti-inflammatory cytokines in patients with PD. Those strains also significantly reduced ROS production in both PD patient and controls. It was found that most strains of bacteria determined restoration of membrane integrity and inhibition of E coli
and K pneumoniae
. Researchers also showed that all the strains didn’t carry the tdc
gene, which has been known to decrease levodopa bioavailability in patients receiving treatment for PD.
The researchers said their findings suggest that probiotics may represent a promising strategy to counteract detrimental immune activation that occurs in PD. They stated that longitudinal studies are required to support the use of bacteriotherapy for patients with PD.
“Overall, our preliminary findings suggest a potential role for probiotic strains in modulating inflammation and oxidative stress and protecting the epithelium from gut permeability.” researchers concluded.
Magistrelli L, Amoruso A, Mogna L, et al. Probiotics may have beneficial effects in Parkinson's disease: in vitro
evidence. Front Immunol
. 2019;10:969. doi: 10.3389/fimmu.2019.00969.