Abstract
Mechanical bowel preparation (MBP) is essential for visualisation of the colon during colonoscopy. Previous studies have identified changes in gut microbiota composition after MBP and colonoscopy. Considering the gut microbiota is increasingly implicated in psychiatry, we explored the potential impact of this intervention on mood and the microbiota-gut-brain axis. We conducted a pre-post intervention study in adults, with timepoints of one week before and one month after MBP and colonoscopy. Our primary outcome was change in average Hospital Anxiety and Depression Scale depression sub-scores. We examined changes in average anxiety, stress, and quality of life scores and gut microbiota composition using 16S rRNA sequencing. We further explored associations between changes in depressive symptoms and gut microbiota and conducted post hoc analyses to explore potential effect modifiers. Average depressive symptom scores decreased one month post-procedure compared to baseline (n = 59; adjusted β = -0.64; 95%CI: -1.18, -0.11). Irritable bowel syndrome (IBS) appeared to moderate this relationship (β = 1.78; 95%CI: 0.292, 3.26); depressive symptoms increased in those with, and decreased in those without, IBS. Reduced alpha diversity, modest effects on beta-diversity, and increases in health-associated genera were observed one month post-procedure. Increases in the CLR-transformed abundances of Ruminococcaceae UCG-009 were associated with improvements in depressive symptoms. There is preliminary evidence of a potential mental health effect of MBP and colonoscopy, particularly for those with IBS, which may be associated with changes to the gut microbiota. Further research is required to confirm these findings and their clinical relevance.
Keywords:
bowel preparation; colonoscopy; depression; gut microbiota; microbiota–gut–brain axis.
Grants and funding
This research received no external funding. A.J.M. is funded through the NHMRC supported Centre for Research Excellence for the Development of Innovative Therapies (CREDIT CRE). M.B. is supported by an NHMRC Senior Principal Research Fellowship and Leadership 3 Investigator grant (1156072 and 2017131). M.B. has received Grant/Research Support from the NIH, Cooperative Research Centre, Simons Autism Foundation, Cancer Council of Victoria, Stanley Medical Research Foundation, Medical Benefits Fund, National Health and Medical Research Council, Medical Research Futures Fund, Beyond Blue, Rotary Health, A2 milk company, Meat and Livestock Board, Woolworths, Avant, and the Harry Windsor Foundation; has been a speaker for Abbot, Astra Zeneca, Janssen and Janssen, and Lundbeck and Merck; and served as a consultant to Allergan, Astra Zeneca, Bioadvantex, Bionomics, Collaborative Medicinal Development, Janssen and Janssen, Lundbeck Merck, Pfizer, and Servier—all unrelated to this work. A.L. is supported by a Deakin Dean’s Postdoctoral Research Fellowship. A.L. has received grant, research, or travel support from Deakin University, the University of Melbourne, RMIT University, National Health and Medical Research Council, Australian Academy of Science, the Jack Brockhoff Foundation, Epilepsy Foundation of Australia, and American Epilepsy Society and has received speakers’ honoraria from European Space Agency and Swisse Australia—all unrelated to this work. M.M. has received grant/research support from the NHMRC, Deakin University School of Medicine, Deakin Biostatistics Unit, Institute for Mental and Physical Health and Clinical Translation, Stroke Foundation, and Medibank Health Research Fund. F.N.J. has received competitive grant/research support from the Brain and Behaviour Research Institute, the National Health and Medical Research Council (NHMRC), Australian Rotary Health, the Geelong Medical Research Foundation, the Ian Potter Foundation, and the University of Melbourne; industry support for research from Meat and Livestock Australia, Woolworths Limited, the A2 Milk Company, and Be Fit Foods; philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, and the Waterloo Foundation; and travel support and speakers honoraria from Sanofi-Synthelabo, Janssen Cilag, Servier, Pfizer, Network Nutrition, Angelini Farmaceutica, Eli Lilly, and Metagenics. She is on the Scientific Advisory Board of the Dauten Family Centre for Bipolar Treatment Innovation and Zoe Limited. F.N.J. has written two books for commercial publication. She is currently supported by an NHMRC Investigator Grant L1 (#1194982). The Food & Mood Centre has received grant/research support from the a2 Milk Company, Be Fit Foods, Meat and Livestock Australia, and Woolworths Limited, and philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, and the Waterloo Foundation.