Biology subjects

Fay, F.

Publications and source records attributed to Fay, F..

3 recordsLinked to original sources

bioRxiv2024

Cognitive-and lifestyle-related microstructural variation in the ageing human hippocampus

Ageing is a biological process associated with the natural degeneration of various regions of the brain. Alteration of neural tissue in the hippocampus with ageing typically results in cognitive decline that may serve as a risk factor for dementia and other neurodegenerative diseases. Modifiable lifestyle factors may help preserve hippocampal neural tissue (microstructure) and slow down neurodegeneration and thus promote healthy cognition in old age. In this study, we sought to identify potential modifiable lifestyle factors that may help preserve microstructure in the hippocampus. We used data from 494 subjects (36-100 years old) without clinical cognitive impairment from the Human Connectome Project-Aging study. We estimated hippocampal microstructure using myelin-sensitive (T1w/T2w ratio), inflammation-sensitive (MD) and fibre-sensitive (FA) MRI markers. Non-negative matrix factorization was used to integrate the signals of these images into a multivariate spatial signature of microstructure covariance across the hippocampus. The associations between hippocampal microstructural patterns and lifestyle factors & cognition were identified using partial least squares analysis. Our results reveal that the preservation of axon density and myelin in regions corresponding to subicular regions and CA1 to CA3 regions of the hippocampi of younger adults is associated with improved performance in executive function tasks, however, this is also associated with a decreased performance in memory tasks. We also show that microstructure is preserved across the hippocampus when there is normal hearing levels, physical fitness and normal insulin levels in younger adults of our study even in the presence of cardiovascular risk factors like high body mass index, blood pressure, triglycerides and blood glucose known to be associated with hippocampal neurodegeneration. This preservation is not observed in older adults when there are no normal levels of insulin, physical fitness and hearing. Taken together, our results suggest that certain lifestyle factors like normal hearing, physical fitness and normal insulin levels may help preserve hippocampal microstructure which may be useful in maintaining optimum performance on executive function tasks and potentially other modes of cognition.

neuroscience↗

bioRxiv2023

Generation of a robust reference gut microbiome dataset for an urban population in Argentina optimized by a machine learning approach

Robust human microbiome analysis requires robust reference datasets obtained from a population that presents similar habits to the one we are trying to assess. We reported here the construction of a robust reference dataset of healthy individuals from urban and surrounding rural areas of the Argentine population. We screened 200 volunteers with strict inclusion/exclusion criteria. Volunteers were also screened with routine blood clinical test analysis and a complete metabolome profile from blood and urine to remove outliers before inclusion in the Next Generation Sequencing dataset. Sequencing was done on an Illumina MiSeq using the V3-V4 16S rRNA. Using these data, we performed de novo community structure prediction by applying clustering methodology based on seven distance and dissimilarity metrics and two clustering methods to the reference set. Using this approach, we discovered four different enterotypes in this community structure. We then trained a model for the classification of any new sample into the structure of the reference set. Once the new sample was classified, it was compared to the reference ranges of both the enterotype-specific subset and the whole reference set. Finally, we challenged the robustness of this methodology using samples from two test case volunteers with clinically proven gut dysbiosis in a time-series sampling with dietary interventions. Our results pointed to the need to carefully analyze the results of gut microbiome in the context of enterotype-specific rather than to a whole population dataset.

microbiology↗

bioRxiv2017

Case-control study highlights a different gut microbiome in cirrhotic patients with and without hepatocellular carcinoma

BackgroundNo specific microbiome in patients with hepatocellular carcinoma (HCC) has been reported to date.\n\nAimTo compare the gut microbiome found in cirrhotic patients with and without HCC.\n\nMethodsFrom 407 patients with Child Pugh A/B cirrhosis prospectively followed, 25 with HCC (cases) were matched with 25 without HCC (wo-HCC) in a 1:1 ratio according to age, gender, etiology, Child Pugh and severity of portal hypertension. In addition results were also compared with 25 healthy subjects. Faecal stool samples were collected noninvasively, aliquoted for DNA extraction and sequenced for the V3-V4 region of the microbial 16S rRNA (Illumina MiSeq Platform).\n\nResultsThere were no significant clinical differences among cases and controls. We found a differential abundance in family members of Firmicutes with a 3-fold increased of Erysipelotrichaceae and a 5-fold decrease in family Leuconostocaceae in HCC when compared to wo-HCC controls. Genus Fusobacterium was found 5-fold decreased in HCC versus wo-HCC. The ratio bacteriodes/prevotella was increased in HCC due to the significant decrease in the genus prevotella. Genus Odoribacter and Butyricimonas were more differentialy abundant in HCC. This pattern has been previously associated with an inflammatory milieu with a putative increased activation of NOD-like receptor signalling pathways. A Random Forest model trained with differential abundant taxa correctly classifyed HCC individuals with an error of 22%.\n\nConclusionsA pattern of microbiome linked to inflammation was observed in cirrhotic patients with HCC. These findings open the discussion whether or not microbiota has a physiopathologic role in HCC development in cirrhosis.

cancer biology↗