| 1. |
- Barazanji, Nawroz, et al.
(author)
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Irritable bowel syndrome in women: Association between decreased insular subregion volumes and gastrointestinal symptoms
- 2022
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In: NeuroImage. - : Elsevier. - 2213-1582. ; 35
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Journal article (peer-reviewed)abstract
- Irritable bowel syndrome (IBS) is a chronic pain disorder characterized by disturbed interactions between the gut and the brain with depression as a common comorbidity. In both IBS and depression, structural brain alterations of the insular cortices, key structures for pain processing and interoception, have been demonstrated but the specificity of these findings remains unclear. We compared the gray matter volume (GMV) of insular cortex (IC) subregions in IBS women and healthy controls (HC) and examined relations to gastrointestinal (GI) symptoms and glutamate + glutamine (Glx) concentrations. We further analyzed GMV of IC subregions in women with major depression (MDD) compared to HC and addressed possible differences between depression, IBS, IBS with depression and HC.
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| 2. |
- Simon, Rozalyn, 1979-, et al.
(author)
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Magnetotactic bacteria from the human gut microbiome associated with orientation and navigation regions of the brain
- 2021
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In: Journal of Oceanology and Limnology. - : Springer Nature. - 2096-5508 .- 2523-3521. ; 39:6, s. 2044-2052
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Journal article (peer-reviewed)abstract
- Magnetotactic bacteria (MTB), ubiquitous in soil and fresh and saltwater sources have been identified in the microbiome of humans and many animals. MTB endogenously produce magnetic nanocrystals enabling them to orient and navigate along geomagnetic fields. Similar magnetite deposits have been found throughout the tissues of the human brain, including brain regions associated with orientation such as the cerebellum and hippocampus, the origins of which remain unknown. Speculation over the role and source of MTB in humans, as well as any association with the brain, remain unanswered. We performed a metagenomic analysis of the gut microbiome of 34 healthy females as well as grey matter volume analysis in magnetite-rich brain regions associated with orientation and navigation with the goal of identifying specific MTB that could be associated with brain structure in orientation and navigation regions. We identified seven MTB in the human gut microbiome: Magnetococcus marinus, Magnetospira sp. QH-2, Magnetospirillum magneticum, Magnetospirillum sp. ME-1, Magnetospirillum sp. XM-1, Magnetospirillum gryphiswaldense, and Desulfovibrio magneticus. Our preliminary results show significant negative associations between multiple MTB with bilateral flocculonodular lobes of the cerebellum and hippocampus (adjusted for total intracranial volume, uncorrected P<0.05). These findings indicate that MTB in the gut are associated with grey matter volume in magnetite-rich brain regions related to orientation and navigation. These preliminary findings support MTB as a potential biogenic source for brain magnetite in humans. Further studies will be necessary to validate and elucidate the relationship between these bacteria, magnetite concentrations, and brain function.
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| 3. |
- Simon, Rozalyn, et al.
(author)
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Vasoactive intestinal polypeptide plasma levels associated with affective symptoms and brain structure and function in healthy females
- 2021
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In: Scientific Reports. - : Nature Research. - 2045-2322. ; 11:1
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Journal article (peer-reviewed)abstract
- Vasoactive intestinal polypeptide (VIP) is a neuroendocrine peptide distributed throughout the human body, including the CNS, where it is particularly abundant in brain regions associated with anxiety and depression. Based on earlier studies indicating that peripheral VIP may cross through the blood-brain barrier, we hypothesized plasma VIP levels to be associated with symptoms of anxiety and depression, as well as brain volume and resting-state functional connectivity in the amygdala, hippocampus, parahippocampus, and orbitofrontal cortex. Plasma VIP concentrations and anxiety/depression symptoms were measured in 37 healthy females. Functional and structural magnetic resonance imaging were used to evaluate functional connectivity and brain volume respectively, and their associations with VIP concentrations within brain regions associated with anxiety and depression. Negative correlations were found between VIP levels and symptoms of anxiety (r=- 0.44, p=0.002) and depression (r=- 0.50, p=0.001). Functional connectivity demonstrated significant VIP-dependent positive associations between the amygdala seed region with both the right parahippocampus (t((33))=3.1, p(FDR)=0.02) and right lateral orbitofrontal cortex (OFC; t((33))=2.9, p(FDR)=0.02). Moreover, VIP concentrations were significantly, positively correlated with brain volume in the left amygdala (r=0.28, p=0.007) and left lateral OFC (r=0.29, p=0.004). The present findings highlight a potential role for VIP in the neurobiology of affective symptoms.
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