How does the microbiota influence the brain?

06/11/2023 at 04:11:59

Have you heard of microbiota? Do you know the relationship of microbiota to brain function?

It has long been known that anxiety or stress situations can cause abdominal discomfort, such as the famous “butterflies in the stomach” when you fall in love with someone or pain before an important performance. Recent studies have shown that there is a sophisticated and complex relationship between the brain and the gastrointestinal system [1]. Thus, it is important to define the concept of microbiota and how it influences our brain.

What is microbiota?

The term "microbiota" refers to the set of microorganisms in a given environment. Therefore, the human microbiota refers to microorganisms that reside in the human organism and bring mutual benefits, since they fulfill several functions such as: stimulate the immune system, break down food compounds with potential toxicity and synthesize some vitamins and amino acids that would not be synthesized in the body. human. [2,3].

An adult individual has about trillions of microorganisms and this microbiota is related to a series of fundamental processes for survival such as prevention against pathogenic microorganisms [4]. Communication between the brain and the gut happens in a two-way way: behavior alters gut flora and gut behavior alters [1]. Thus, the population of intestinal microorganisms may affect emotional well-being and the onset of psychological and psychiatric disorders.

So what is the relationship of microbiota with behavioral disorders?

Recent studies have shown that gut microbiota imbalance can cause a number of diseases, not just linked to the digestive system; it may also be part of the etiology of neurodevelopmental disorders [4].

People with depression have a different intestinal flora than those without depression. In a study by a group of Chinese researchers, mice that had no germ free received fecal transplantation of depressed mice, and it was observed that they began to show symptoms, so it was possible to infer that the microbiome Bowel disease may have a causal role in the development of depressive-type behaviors [5].

In 2015, an analysis was conducted with more than 100,000 children. Children diagnosed with autistic spectrum disorder (ASD) have been found to have more bowel problems such as constipation, diarrhea, intolerance or allergies [6].

Microbiota and sociability

Sociality can facilitate mutually beneficial outcomes such as division of labor, cooperative assistance and increased immunity, but sociality can also promote negative outcomes, including aggression and coercion. Evidence suggests that the microbiota residing in the gastrointestinal system may influence neurodevelopment and the programming of social behaviors in various animal species. Sociability comprises a complex range of interactive behaviors that can be cooperative, neutral or antagonistic. Throughout the animal kingdom, the level of sociability an animal exhibits is variable; some are highly social (eg, primates, termites and bees), living in cooperative communities, while others have a mostly solitary existence (eg, bears) [7].

The relationship between host and microbes suggests that host-microbiota interactions may have influenced the evolution of social behaviors. Although these connections between intestinal bacteria and neurodevelopmental disorders are currently an intriguing area of research, any role of microbiota in the evolution of social behavior in animals does not replace other contributing factors. Instead, it adds an additional perspective on how these complex behaviors emerged [7].

Understanding this relationship between microbiota and social behavior is important both in the sphere of evolution of brain physiology and behavior, but also in terms of providing a better understanding of the identification of pathways for the treatment of social disorders in humans.

Autor Erik Rodrigues

References

[1] OLIVEIRA, Sophia La Banca de; MORAES, Eduardo Cruz. A microbiota intestinal influencia o comportamento. 2018. Disponível em: <http://www.comciencia.br/microbiota-intestinal-influencia-o-comportamento/>.

[2] GONÇALVES, M. A. P. Microbiota – implicações na imunidade e no metabolismo. 2014. 53p. Dissertação (Mestrado em Ciências Farmacêuticas). Universidade Fernando Pessoa, Porto, Portugal, 2014. Disponível em: <http://bdigital.ufp.pt/bitstream/10284/4516/1/PPG_21951.pdf>

[3] FÁBIO, André Cabette. O que é microbiota e por que ela tem sido foco de pesquisas. 2018. Disponível em: <https://www.nexojornal.com.br/expresso/2018/11/14/O-que-é-microbiota-e-por-que-ela-tem-sido-foco-de-pesquisas>.

[4] LOUZADA, Fernando. Alterações na composição de microrganismos podem estar associadas à gênese do transtorno do espectro autista. 2019. Disponível em: <https://www.revistaeducacao.com.br/neurodesenvolvimento-autista/>.

[5] ZHENG, P et al. Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host’s metabolism. Molecular Psychiatry, [s.l.], v. 21, n. 6, p.786-796, 12 abr. 2016. Springer Nature. http://dx.doi.org/10.1038/mp.2016.44.

[6] BRESNAHAN, Michaeline et al. Association of Maternal Report of Infant and Toddler Gastrointestinal Symptoms With Autism. Jama Psychiatry, [s.l.], v. 72, n. 5, p.466-483, 1 maio 2015. American Medical Association (AMA). http://dx.doi.org/10.1001/jamapsychiatry.2014.3034.

[7] SHERWIN, Eoin et al. Microbiota and the social brain. Science, [s.l.], v. 366, n. 6465, p.1-15, 31 out. 2019. American Association for the Advancement of Science (AAAS). http://dx.doi.org/10.1126/science.aar2016.

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How does the microbiota influence the brain?