Relationship between Autism and Microbiota

DEFINITIONS:

• Autism: It is a complex behavioral syndrome characterized by speech and language disorders, mental impairment, and learning and motor dysfunctions.
• Gastro Intestinal System (GIS): It describes the entire digestive system from the mouth to the anus.
• Microbiota: Microbiota is “ecological communities formed by commensal, symbiotic and pathogenic microorganisms” and are found on the inner and outer surfaces of all multicellular organisms that have been studied, from plants to animals. The microbiota includes bacteria, archaea, protists, fungi and viruses. Depending on their location, they are named as “Intestinal Microbiota” or “Intraoral Microbiota”. Where they are found and settled is not a coincidence. Each of them has functions specific to the region in which it is located. Briefly, we can define it as the sum of microorganisms (bacteria, fungi, virus and protozoa families) that live in our body and are not human cells. It is also called FLORA.
• Micromyoma: It defines the genome structure that forms the microbiota.
• Leaky Gut Syndrome (GBS) / Leaky Gut Syndrome (LGS): Our intestines have selective permeability, thanks to the barriers on the intestinal absorption surface. As a result of the decrease in microbiota biodiversity, the increase in pathogenic microorganisms (Dysbiosis), the excessive increase in bacteria in the small intestines (SIBO DISEASE) and the inability to maintain quality mucus secretion, our intestines lose their “SELECTIVE PERMEABLE” feature. The umbrella definition of diseases presenting with this picture is LEAKY GUT SYNDROME.
• Dysbiosis: It describes the increase of pathogenic microorganisms instead of beneficial microorganisms (FLORA) in the intestines.
• Trimester: It is the name given to each 3-month period of the 9-month gestation period in humans.
• Fetus: 9-40 days of pregnancy. It is the name given to the living thing in the womb between weeks and weeks. The first eight weeks are called the embryonal period.
• Commensalism: It is a type of life in which two organisms live together, where one organism benefits and the other is not affected by this partnership.
• Symbiosis: Two organisms living together by helping each other as a single organism.
• Pathogen: Any organism or substance that causes disease.

AUTISM is a disease characterized by unusual behaviors, difficulties in communicating and establishing relationships with the environment, and indifference or hypersensitivity responses to sensory signals from the environment (1). The diagnosis of autism is usually made at the age of 2-3, after the child is taken to the doctor due to lack of communication and skills. Both genetic and environmental factors play a role in autism, but most cases of autism are idiopathic (cause unknown) (2). Autism is observed more in men than women (3). In large-scale studies, it is known that one in every 46 live births is autistic (4). There are many factors blamed for the development of autism. A significant portion of these are associated with situations encountered in embryonal and fetal life, some are related to the type of birth, and some are associated with postnatal processes. Maternal infection during pregnancy can lead to changes in the microbial composition as well as an increased risk of autism. It was determined that women who were hospitalized due to infection during pregnancy had a higher risk of giving birth to autistic children. Viral infections in the first trimester of pregnancy and bacterial infections in the second trimester are associated with a higher risk of giving birth to an autistic child (5).

In their study, Kang et al. reported that autistic children experienced significantly shorter breastfeeding duration (6). In the study conducted by Swedish scientists Urran et al., using information obtained from a population-based registry including approximately 2.6 million children, they reported that the risk of autism development in the child is 20% higher in cesarean births compared to natural vaginal birth (7). It is also known that many autistic children receive high doses of oral antibiotics in the first years of their lives(2). Premature birth, mode of delivery, and breastfeeding affect the intestinal microbial composition of newborns. Vaginally born babies who are breastfed have the healthiest microbiota composition. (8). Taken together, it has been observed that the risk of developing autism is higher in children born prematurely with very low birth weight, born by cesarean section, and not breastfed ( 9 ). Autism is diagnosed at a much higher rate in those who have been hospitalized for a long time, in those who have been treated with antibiotics for a long time, or in those whose mothers had an infection during pregnancy (5, 10). In a broad-based epigenetic study conducted by Alam et al., it was reported that infections during pregnancy may cause changes in myelination in the brain and possibly behavioral changes as observed in autism (11).

The relationship between autism and microbiota has been demonstrated by many studies. Our intestines have selective permeability and thanks to this barrier, we are protected from many harmful factors. The intestinal barrier consists of commensal intestinal microbiota, mucus layer, and epithelial cells connected by tight junctions (12). It has been shown in many clinical studies that this barrier is more impaired in autistic individuals than in non-autistic individuals, microbiota (FLORA) biodiversity is reduced, and dysbiosis and SIBO are more common. It has also been shown that decreased microbiota diversity in the mother, SIBO and Dysbiosis are directly related to the development of autism in the child.

Microbiota has an important role in maintaining the physiological (healthy) structure in the Gastro Intestinal System (GIS), that is, throughout the digestive system from the mouth to the anus, and some digestive systems (Food Allergy, IBS, Celiac Disease, Gluten Sensitivity, Ulcerative Colitis, Crohn’s Disease, etc.) .) and non-digestive diseases (Autism, Autoimmune Arthritis, Autoimmune Vasculitis, Psoriasis, Dermatitis, Vitiligo, Depression, Type 2 Diabetes, etc.) have been shown in the clinical study conducted by Mangiola et al. that there are qualitative and quantitative changes in the INTESTINAL FLORA (microbiota). (13). In the research conducted by Mangiola and his colleagues, they revealed that disruption of the intestinal microbiota is extremely important in the formation of autism and in the management and treatment of existing autism. Available evidence shows that disruption of the gut microbiota plays a key role in the development of autism and mood disorders (13). Accumulating evidence has demonstrated a link between changes in the composition of the gut microbiota and both gastrointestinal and neurobehavioral symptoms in children with autism. Gut dysbiosis in autism has been widely demonstrated. (14). Many children with autism have abnormalities in GI physiology, including increased intestinal permeability, general microbiota changes, and intestinal infection. Moreover, autistics are described as “picky eaters” and the presence of certain sensory patterns in autistic patients may represent one of the main elements that inhibit feeding. GI disorders are associated with the altered composition of the gut microbiota. The gut microbiome can communicate with brain activities through microbiota-derived signaling molecules, immune system elements and gut hormones, as well as vagal and spinal afferent neurons (15).

Microbiota is a group of microorganisms that colonize the human body, and the composition of this group is not accidental; The term microbiome covers the genomes of all microorganisms in a particular environment. This complex ecosystem is characterized by a network of positive and negative relationships that significantly influence the health of the host ( 16 ). Each member of the microbiota biodiversity has special functions. So far, 1054 different types of FLORA (microbiota) bacteria have been identified throughout the digestive system. No member settles or lives outside the localization to which it belongs (17). Microbial composition varies with age, diet, diseases, geography, and shared environment ( 18 ).

The Gastro Intestinal System (GIS), the largest surface of the body, contains trillions of microorganisms separated by the intestinal barrier. The number of FLORA bacteria living in our intestines alone is 10 times greater than all the cells in our body (19). 90% of all microorganisms in the GIT colonize the initial parts of the small and large intestines (20).

Many eating habits and food-related aggressive behaviors in autism are directly related to FLORA. In addition to dysbiosis, GI symptoms are four times more common in children with ASD compared to the normal population. It was determined that the most common gastrointestinal symptom in children with autism was constipation. The same authors also found a link between rigid persistent behavior and the occurrence of constipation ( 21 ). It has been reported that GI problems in autistic children cause more tantrums, aggressive behavior and sleep disorders, and worsen the behavior compared to autistic individuals without GI symptoms (22). A study suggests that behavioral changes such as aggression, self-harm or sleep disturbance observed in autistic children may be an expression of abdominal discomfort (23).

The intestinal microbiota performs many important functions in our body. First, it maintains the proper functioning of the intestines, ensuring proper pH, proper intestinal peristalsis, and regular bowel movement rhythm. Microorganisms colonizing the intestines not only participate in the digestion of food by secreting digestive enzymes or converting complex nutrients into simpler organic compounds and fat metabolism, but also contribute to the absorption of digested food. In addition to the functions mentioned above, the intestinal microbiota is also responsible for synthesizing some vitamins, especially the B group (24). Through anaerobic fermentation of indigestible carbohydrates (mostly dietary fiber), intestinal microorganisms produce short-chain fatty acids, which are the primary energy source for the epithelial cell of the colon (colonocytes) (25). Another important role of the intestinal microbiota is the neutralization of toxins and carcinogenic compounds (26). In addition, intestinal microorganisms protect our body against the penetration of pathogenic factors by creating the intestinal barrier (27). According to Azouz et al., it was reported that 82.5% of a group of 40 autistic children aged between 3 and 12 had gastrointestinal symptoms (28). Children with autism have a wide range of gastrointestinal symptoms, including constipation, diarrhea, bloating, abdominal pain, reflux, vomiting, excessive intestinal gas, foul-smelling stools, and food allergies (29). In the study conducted by Kang et al., it was determined that the low bacterial diversity found in autistic children was associated with the severity of gastrointestinal symptoms (2).

Otizmli hastaların sindirim sistemi problemlerini tedavi etmenin en etkin ve kalıcı yöntemi FLORA NAKLİDİR (30). Sağlıklı ve biyoçeşitliliği yüksek en az bir donörden yapılacak flora nakli ile hastanın sindirim sistemi mikrobiyotası yeniden tesis edilmiş olur. Flora nakli hakkındaki tüm teknik detaylara https://www.docdrmuratkanlioz.com/flora-nakli/ linki tıklayarak ulaşabilirsiniz.

Assoc. Prof. Murat KANLIÖZ

General surgery specialist

SOURCE:

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