Abstract
A growing body of evidence supports an important role for alterations in the brain-gut-microbiome axis in the aetiology of depression and other psychiatric disorders. The potential role of the oral microbiome in mental health has received little attention, even though it is one of the most diverse microbiomes in the body and oral dysbiosis has been linked to systemic diseases with an underlying inflammatory aetiology. This study examines the structure and composition of the salivary microbiome for the first time in young adults who met the DSM-IV criteria for depression (n = 40) and matched controls (n = 43) using 16S rRNA gene-based next generation sequencing. Subtle but significant differences in alpha and beta diversity of the salivary microbiome were observed, with clear separation of depressed and healthy control cohorts into distinct clusters. A total of 21 bacterial taxa were found to be differentially abundant in the depressed cohort, including increased Neisseria spp. and Prevotella nigrescens, while 19 taxa had a decreased abundance. In this preliminary study we have shown that the composition of the oral microbiome is associated with depression in young adults. Further studies are now warranted, particuarly investigations into whether such shifts play any role in the underling aetiology of depression.
Highlights
This data highlights the potential of the human oral microbiome as a source of novel diagnostic and therapeutic response biomarkers for mood and anxiety disorders
As expected, smoking significantly altered microbiome composition (Fig. 2C).The first canonical axis displays a negative correlation with daily smoking, while the second was positively correlated with depression
Given the well described body of evidence to support the critical role of the gut microbiome in mood disorders, in conjunction with the significant overlap that exists between the taxa in the gut and oral sites, we hypothesised that depression would be associated with measurable changes in the oral microbiome
Summary
This data highlights the potential of the human oral microbiome as a source of novel diagnostic and therapeutic response biomarkers for mood and anxiety disorders. We used bacterial 16S ribosomal RNA (16S rRNA) gene-based generation sequencing (NGS) to profile the bacterial composition of saliva in young adults with depression versus healthy matched controls, and evaluate if changes to the structure and composition of the oral microbiota were associated with depression.
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