Gut microbiota and autism: what is the connection?

Abstract (as presented by the authors of the scientific work):

"Gastrointestinal (GI) symptoms are a common comorbidity in patients with autism spectrum disorder (ASD), but the underlying mechanisms are unknown. Many studies have shown alterations in the composition of the fecal flora and metabolic products of the gut microbiome in patients with ASD. The gut microbiota influences brain development and behaviors through the neuroendocrine, neuroimmune and autonomic nervous systems. In addition, an abnormal gut microbiota is associated with several diseases, such as inflammatory bowel disease (IBD), ASD and mood disorders. Here, we review the bidirectional interactions between the central nervous system and the gastrointestinal tract (brain-gut axis) and the role of the gut microbiota in the central nervous system (CNS) and ASD. Microbiome-mediated therapies might be a safe and effective treatment for ASD."


Covered topics (the letter size corresponds to the frequency of mentioning in the text):

Conclusion (as presented by the authors of the scientific work):

"In this review, we summarize the information from multiple studies showing that an abnormal gut microbiota is related to ASD. First, we reviewed the relationship between the gut microbiota and the CNS. Second, we defined the role of the gut microbiota in ASD. Finally, we described some potential therapies for modulating the gut microbiota in patients with ASD. Many recent clinical studies have shown that treatments that regulate the gut microbiota result in improvements in ASD symptoms (Critchfield et al., 2011; Tomova et al., 2015). However, well-designed research studies with more participants are needed to provide more evidence that supports the effectiveness of these treatments."


Full-text access of the referenced scientific work:

Li Q, Han Y, Dy ABC, Hagerman RJ. The Gut Microbiota and Autism Spectrum
Disorders. Front Cell Neurosci. 2017 Apr 28;11:120. doi:
10.3389/fncel.2017.00120. eCollection 2017. Review. PubMed PMID: 28503135; PubMed
Central PMCID: PMC5408485.
http://journal.frontiersin.org/article/10.3389/fncel.2017.00120/full


Further reading:

Autism spectrum disorder (MedlinePlus): "Autism spectrum disorder (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a person's life. It affects how a person acts and interacts with others, communicates, and learns. It includes what used to be known as Asperger syndrome and pervasive developmental disorders.
It is called a "spectrum" disorder because people with ASD can have a range of symptoms. People with ASD might have problems talking with you, or they might not look you in the eye when you talk to them. They may also have restricted interests and repetitive behaviors. They may spend a lot of time putting things in order, or they may say the same sentence again and again. They may often seem to be in their "own world."
At well-child checkups, the health care provider should check your child's development. If there are signs of ASD, your child will have a comprehensive evaluation. It may include a team of specialists, doing various tests and evaluations to make a diagnosis.
The causes of ASD are not known. Research suggests that both genes and environment play important roles.
There is currently no one standard treatment for ASD. There are many ways to increase your child's ability to grow and learn new skills. Starting them early can lead to better results. Treatments include behavior and communication therapies, skills training, and medicines to control symptoms.
...read more".

Gut microbiota (Wikipedia): "Gut flora (gut microbiota, or gastrointestinal microbiota) is the complex community of microorganisms that live in the digestive tracts of humans and other animals, including insects. The gut metagenome is the aggregate of all the genomes of gut microbiota.[1] The gut is one niche that human microbiota inhabit.[2]
In humans, the gut microbiota has the largest numbers of bacteria and the greatest number of species compared to other areas of the body.[3] In humans the gut flora is established at one to two years after birth, and by that time the intestinal epithelium and the intestinal mucosal barrier that it secretes have co-developed in a way that is tolerant to, and even supportive of, the gut flora and that also provides a barrier to pathogenic organisms.[4][5]
The relationship between some gut flora and humans is not merely commensal (a non-harmful coexistence), but rather a mutualistic relationship.[2]:700 Some human gut microorganisms benefit the host by fermenting dietary fiber into short-chain fatty acids (SCFAs), such as acetic acid and butyric acid, which are then absorbed by the host.[3][6] Intestinal bacteria also play a role in synthesizing vitamin B and vitamin K as well as metabolizing bile acids, sterols, and xenobiotics.[2][6] The systemic importance of the SCFAs and other compounds they produce are like hormones and the gut flora itself appears to function like an endocrine organ,[6] and dysregulation of the gut flora has been correlated with a host of inflammatory and autoimmune conditions.[3][7]
The composition of human gut flora changes over time, when the diet changes, and as overall health changes.[3][7] A systematic review from 2016 examined the preclinical and small human trials that have been conducted with certain commercially available strains of probiotic bacteria and identified those that had the most potential to be useful for certain central nervous system disorders.[8]... read more".

Inflammatory bowel disease (Mayo Clinic): "Inflammatory bowel disease (IBD) involves chronic inflammation of all or part of your digestive tract. IBD primarily includes ulcerative colitis and Crohn's disease. Both usually involve severe diarrhea, pain, fatigue and weight loss. IBD can be debilitating and sometimes leads to life-threatening complications.
Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease that causes long-lasting inflammation and sores (ulcers) in the innermost lining of your large intestine (colon) and rectum.
Crohn's disease is an IBD that cause inflammation of the lining of your digestive tract. In Crohn's disease, inflammation often spreads deep into affected tissues. The inflammation can involve different areas of the digestive tract — the large intestine, small intestine or both.
Collagenous (kuh-LAJ-uh-nus) colitis and lymphocytic colitis also are considered inflammatory bowel diseases but are usually regarded separately from classic inflammatory bowel disease.
.... read more".


Webmaster:

Prof. Atanas G. Atanasov (Dr. habil., PhD)
https://about.me/Atanas_At


Keywords relevant for this post: gut microbiota, probiotics, gut bacteria, gut flora, probiotic supplements, prebiotics, stomach bacteria, intestinal flora, bacteria in stomach, autism, autism spectrum disorder, autism spectrum, signs of autism, autism symptoms, open access, journal, open access journals, science journal, free journal publication, online journal, open access publishing, open access articles, science magazine, journal science, journal of science, treatment, remedy, relief, therapy, medicine, medication, medical treatment, relieve symptoms.