Neighbourhood environment as a risk factor for adverse health outcomes through association with the microbiome: protocol for a scoping review.

INTRODUCTION: The connection of the microbiome to human health intersects with the physical environment of humans. Each microbiome location can be influenced by environmental conditions that relate to specific geographical locations, which in turn are influenced by social determinants of health such as a neighbourhood. The objective of this scoping review is to explore the current evidence on the relationships between microbiome and neighbourhood to explain microbiome-related health outcomes. METHODS AND ANALYSIS: Arksey and O'Malley's literature review framework will be employed throughout the process, as well as Page, et al's 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis updated workflow to process search results. The literature search will be completed using PubMed/Medline (NLM), Embase (Elsevier), Web of Science, Core Collection (Clarivate Analytics), Scopus (Elsevier), medRxiv preprint server and Open Science Framework server. The search will be conducted using a list of pre-identified Medical Subject Headings (MeSH) terms relating to neighbourhood, microbiome and individual characteristics. There will be no date or language restrictions used in the search. In order to be included in the study, a piece must include an evaluation of the relationship between microbiome diversity and neighbourhood (including at least one measurement of the neighbourhood and at least one human microbiome site). Excluded from the review will be those works that do not include all of these measures, literature reviews based on secondary sources and postmortem populations with no report of premortem health factors. The review itself will be an iterative process completed by two reviewers, with a third individual identified to break ties. Documents will be undergoing a risk assessment of bias in order for the authors to comment on the quality of the literature in this area. Finally, results will be discussed with identified stakeholders, including individuals connected to neighbourhoods facing structural inequity and experts in the topics of study through a community advisory board, for their feedback and knowledge transfer. ETHICS AND DISSEMINATION: This review does not require ethical approval. Results of this search will be disseminated through peer-reviewed publications. Furthermore, this work is completed in conjunction with a community advisory board so as to ensure dissemination to multiple stakeholders.

An exploratory study of pro-inflammatory cytokines in individuals with alcohol use disorder: MCP-1 and IL-8 associated with alcohol consumption, sleep quality, anxiety, depression, and liver biomarkers.

Background: High levels of sleep disturbances reported among individuals with alcohol use disorder (AUD) can stimulate inflammatory gene expression, and in turn, may alter pro-inflammatory cytokines levels. We aimed to investigate associations between pro-inflammatory cytokine markers with subjective measures of sleep quality, psychological variables and alcohol consumption among individuals with AUD. Methods: This exploratory study is comprised of individuals with AUD (n = 50) and healthy volunteers (n = 14). Spearman correlation was used to investigate correlations between plasma cytokine levels and clinical variables of interest (liver and inflammatory markers, sleep quality, patient reported anxiety/depression scores, and presence of mood and/or anxiety disorders (DSM IV/5); and history of alcohol use variables. Results: The AUD group was significantly older, with poorer sleep quality, higher anxiety/depression scores, and higher average drinks per day as compared to controls. Within the AUD group, IL-8 and MCP-1 had positive significant correlations with sleep, anxiety, depression and drinking variables. Specifically, higher levels of MCP-1 were associated with poorer sleep (p = 0.004), higher scores of anxiety (p = 0.006) and depression (p < 0.001), and higher number of drinking days (p = 0.002), average drinks per day (p < 0.001), heavy drinking days (p < 0.001) and total number of drinks (p < 0.001). The multiple linear regression model for MCP-1 showed that after controlling for sleep status and heavy drinking days, older participants (p = 0.003) with more drinks per day (p = 0.016), and higher alkaline phosphatase level (p = 0.001) had higher MCP-1 level. Conclusion: This exploratory analysis revealed associations with cytokines MCP-1 and IL-8 and drinking consumption, sleep quality, and anxiety and depression in the AUD group. Furthermore, inflammatory and liver markers were highly correlated with certain pro-inflammatory cytokines in the AUD group suggesting a possible relationship between chronic alcohol use and inflammation. These associations may contribute to prolonged inflammatory responses and potentially higher risk of co-morbid chronic diseases.

Examining the Relationships Between Sleep Physiology and the Gut Microbiome in Preclinical and Translational Research: Protocol for a Scoping Review.

BACKGROUND: Sleep is an instrumental behavioral state with evidence supporting its active role in brain function, metabolism, immune function, and cardiovascular systems. Research supports that there are pathways underlying the bidirectional communication between the brain and gastrointestinal system, also known as the "gut-brain axis." Primary research examining sleep and gut microbiome relationships continues to increase. Although current data include both preclinical and clinical research, gut microbiome results are reported through a wide range of metrics (alpha diversity, beta diversity, and bacterial compositional changes), which makes cross-study comparison challenging. Therefore, a synthesis of the research examining sleep and gut microbiome relationships is necessary to understand the state of the science and address gaps in the literature for future research. OBJECTIVE: In this paper, we outline a scoping review protocol to evaluate and synthesize preclinical and clinical primary research focused on the associations between sleep and the gut microbiome. METHODS: The search strategy was facilitated through a medical research librarian and involved electronic databases including PubMed/MEDLINE, Embase, Scopus, Web of Science, CENTRAL trials database, BIOSIS Citation Index, and the Zoological Record. Gray literature sources including medRxiv and bioRxiv preprint servers were also searched. Studies were screened according to the aims and exclusion and inclusion criteria of the protocol. After screening, data will be extracted and synthesized from the included studies according to predefined sleep and microbiome methodology metrics. RESULTS: The search strategy yielded 4622 references that were imported for study screening, and source screening was completed in May 2022 by 2 independent investigators, resulting in a total of 93 sources for data extraction and synthesis. The data synthesis table is expected to be completed by August 2022, and the results will be disseminated through paper submission by December 2022 and presented at conferences related to neuroscience, sleep physiology, bioinformatics, and the microbiome. CONCLUSIONS: A scoping review of preclinical and clinical research is needed to synthesize the growing data focused on the relationships between sleep and the gut microbiome. We expect the results of this synthesis will identify gaps in the literature and highlight pathways linking the gut-brain axis and sleep physiology to stimulate future research questions. TRIAL REGISTRATION: Open Science Framework 69TBR; https://osf.io/69tbr. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/38605.