Parkinson's disease: Are gut microbes involved?

Abstract

Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by motor and gastrointestinal (GI) deficits. Despite its prevalence, the pathophysiology of PD is not well understood. Recent studies highlight the role of gut microbiota in neurological disorders. In this review, we summarize the potential role of gut microbiota in the pathophysiology of PD. We first describe how gut microbiota can be influenced by factors predisposing individuals to PD, such as environmental toxins, aging, and host genetics. We then highlight the effect of gut microbiota on mechanisms implicated in the pathophysiology of PD, including disrupted microbiota gut brain axis (GBA), barrier dysfunction, and immune dysfunction. It is too early to connect the dots between gut microbiota and PD to establish causation, and experiments focused on investigating interrelationship between gut microbiota and associated metabolites on GBA, barrier dysfunction, and immune activation will be crucial to fill in the gaps.

Keywords: Parkinson’s disease; gut brain axis; gut microbiota.

Conflict of interest statement

P. Kashyap is a member of the Advisory Board of Novome and a consultant for Otsuka Pharmaceuticals, Pendulum Therapeutics, and IP Group, Inc. Y. Bhattarai is a scientist at Takeda Pharmaceuticals.

Figures

Graphical abstract

Fig. 1.

Figure highlights gut microbiota-associated mechanistic pathways that regulate gastrointestinal and motor dysfunction in Parkinson’s disease. Environmental toxins consumption alters gut microbiota composition and leads to disruption in epithelial barrier (1), alteration in immune activation (2), and disrupted microbiota-gut-brain axis communication through vagal and nonvagal pathways (3) to cause gastrointestinal and motor dysfunction in Parkinson’s disease. TLRs, Toll-like receptors; ZO-1, zona occludins 1.