The gut microbiome is associated with brain structure and function in schizophrenia

Abstract

The effect of the gut microbiome on the central nervous system and its possible role in mental disorders have received increasing attention. However, knowledge about the relationship between the gut microbiome and brain structure and function is still very limited. Here, we used 16S rRNA sequencing with structural magnetic resonance imaging (sMRI) and resting-state functional (rs-fMRI) to investigate differences in fecal microbiota between 38 patients with schizophrenia (SZ) and 38 demographically matched normal controls (NCs) and explored whether such differences were associated with brain structure and function. At the genus level, we found that the relative abundance of Ruminococcus and Roseburia was significantly lower, whereas the abundance of Veillonella was significantly higher in SZ patients than in NCs. Additionally, the analysis of MRI data revealed that several brain regions showed significantly lower gray matter volume (GMV) and regional homogeneity (ReHo) but significantly higher amplitude of low-frequency fluctuation in SZ patients than in NCs. Moreover, the alpha diversity of the gut microbiota showed a strong linear relationship with the values of both GMV and ReHo. In SZ patients, the ReHo indexes in the right STC (r = − 0.35, p = 0.031, FDR corrected p = 0.039), the left cuneus (r = − 0.33, p = 0.044, FDR corrected p = 0.053) and the right MTC (r = − 0.34, p = 0.03, FDR corrected p = 0.052) were negatively correlated with the abundance of the genus Roseburia. Our results suggest that the potential role of the gut microbiome in SZ is related to alterations in brain structure and function. This study provides insights into the underlying neuropathology of SZ.

Involvement of Gut Microbiota in Schizophrenia and Treatment Resistance to Antipsychotics

“…The presence of a distinct signature of gut microbiota components in patients affected by SCZ compared to HC is consistent with emerging evidence that molecular substrates of social, cognitive and emotional domains, known to be altered in SCZ, might be influenced by life-long microbiota–gut–brain axis signaling [ 41 ]. Indeed, a recent study showed that the higher relative abundance of genus Roseburia in SCZ patients, compared to HC, was negatively correlated with the regional homogeneity indexes of brain regions putatively involved in the pathophysiology of SCZ, such as the right superior temporal cortex, the left cuneus and the right medial temporal cortex [ 42 ].…”

Compositional and functional alterations in the oral and gut microbiota in patients with psychosis or schizophrenia: A systematic review

“…A smaller number of studies explore the predicted or actual functional alterations in microbial genes or metabolic pathways associated with these differences [41][42][43] . Changes in microbiota composition in psychosis and schizophrenia have been correlated with altered brain structure and function, altered immunity, altered metabolic pathways and symptom severity.…”

“…Growing evidence suggests that there are differences in the alpha and beta diversity in the microbial composition of people with psychosis and schizophrenia as compared with controls 21 , 23 , 40 . A smaller number of studies explore the predicted or actual functional alterations in microbial genes or metabolic pathways associated with these differences 41 – 43 . Changes in microbiota composition in psychosis and schizophrenia have been correlated with altered brain structure and function, altered immunity, altered metabolic pathways and symptom severity.…”

The Microbiota/Microbiome and the Gut–Brain Axis: How Much Do They Matter in Psychiatry?

“…Moreover, a comparison of MRI images highlighted significant differences in both the volume of gray matter and the regional homogeneity amongst the two groups and higher amplitudes of low-frequency fluctuation in SZ patients. Finally, both changes in gray matter volume and regional homogeneity correlated with the diversity of the gut microbiota [ 171 ]. In a similar fashion, significant changes in the volume of the right middle frontal gyrus seem to be related to the specific composition of gut microbiota in SZ [ 163 ].…”