A group of researchers from Weill Cornell Medicine – Qatar (WCM-Q) have examined the relationship between neurodevelopmental and gastrointestinal disorders, and the natural bacteria and fungi found within the body.

People suffering from neurodevelopmental illnesses like autism and attention deficit hyperactivity disorders often experience gastrointestinal issues, and conversely, patients with gastrointestinal diseases are more likely to have issues with anxiety.

Bacteriomes and mycobiome

To try to understand this, researchers at WCM-Q conducted a pilot study involving 55 volunteers to look at their individual bacteriomes (the bacteria living naturally in their bodies) and mycobiome (the fungi found naturally in their bodies). Each volunteer had either neurodevelopment or gastrointestinal issue, along with a control group of individuals who had neither. Variables such as diet and intake of probiotic samples were also taken into consideration.

Each volunteer answered a questionnaire and provided a stool sample. The different species of bacteria and fungi in each sample were analysed.

Dr Ghizlane Bendriss, a lecturer in biology at WCM-Q received a grant from Qatar National Research Fund back in 2017 to lead the research. The project won interest in 2020 after winning first place in the annual UREP competition.

According to Dr Bendriss, the role of gut microbiota, which includes bacteria and fungi along with protists, viruses and archaea, is increasingly recognised to have a significant impact on health. Imbalances in the diversity and abundance of microbial communities have been consistently linked to a variety of modern diseases, including neurodegenerative illnesses, cancers and autoimmune diseases.

Most studies, however, have focused on the bacteriome, while neglecting the mycobiome, despite fungi being naturally found throughout the human body.

She said that the body’s microbiome is affected by a range of lifestyle factors including sleep, diet, antibiotic intake and physical activity. Processed carbohydrates like white flour, breakfast cereals, white bread and sugar have been shown to have a particularly strong effect on the microbiome, greatly altering its composition.

But despite Qatar having a relatively high rate of autism spectrum disorders at 1.81% compared to a global average of 0.6-1%, no studies have analysed the microbial signatures of affected individuals.

WCM-Q researchers

Dr Bendriss conducted the study with fellow WCM-Q faculty members Dr Noha Yousri, Dr Dalia Zakaria and Dr Ali Chaari. Students Ibrahim Laswi (first author), Ameena Shafiq, Dana Al Ali, Nada Mhaimeed, Mohammed Salameh, Zain Burney, and Krishnadev Pillai also worked on the project.

The publication, titled ‘A Comparative Pilot Study of Bacterial and Fungal Dysbiosis in Neurodevelopmental Disorders and Gastrointestinal Disorders: Commonalities, Specificities and Correlations with Lifestyle’, has been published in the journal Microorganisms.

Antibiotics and autism

It found that for neurodevelopmental illnesses, the fungal diversity of the microbiome actually increased, while the variety of bacteria decreased. For gastrointestinal diseases, there were only a small number of significant differences in the bacteriome but there was an increase of 10 different species of fungus compared to the control group, and a further eight species that were increased in number compared to the samples from the neurodevelopmental group. It was also found that probiotic intake, diet and exposure to antibiotics had a much greater effect on the mycobiome than the bacteriome.

The results of this study support previously published data that suggested a statistically significant association between exposure to antibiotics in the early years of life – between 0 and three years old – and the development of neurodevelopmental disorders such as autism. Further research now needs to be conducted on the interactions between the gut, external factors and the development of certain diseases.

Dr Bendriss said that as the interest in the mechanisms underlying pathologies relating to the microbiome grows, comparing the gut composition of those with neurodevelopmental disorders and gastrointestinal diseases is essential to further understand the relationship between these two sets of disorders. In addition, exploring both the bacteriome and the mycobiome is necessary, as is the role of external factors like diet, exercise and probiotic intake.

For more information about WCM-Q, visit qatar-weill.cornell.edu

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