Intestinal inflammation and compromised barrier function in idiopathic parkinsonism: scenario captured by systematic review

Abstract

This article is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Abstract Aim: To address how common are intestinal inflammation and compromised barrier function in idiopathic parkinsonism (IP), any potential treatment benefits, outcome of not treating, and whether screening is worthwhile. This may provide the missing link between systemic/brain inflammation in IP and implicated gastrointestinal microbiota/specific pathogens. Methods: Search strategy was based on PRISMA guidelines. Fifteen of the 1395 articles (1995-2020) identified met the inclusion criteria. Seven gave results on more than one intestinal modality: inflammation, permeability, integrity, and bacterial translocation. Results: The interrelationship of IP with intestinal inflammation and bacterial translocation is firmly established, lacking only random sample surveys to meet Level-1 Oxford Centre for Evidence-Based Medicine evidence. Evidence for reduced integrity is limited to 2 small studies of tight-junction proteins in colonic biopsies. No overall conclusion can be drawn from studies of faecal and circulating markers of integrity: evidence based on an assay that recognizes wider zonulin family, not the specific peptide exclusively, was censored. Evidence for increased permeability is