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Advanced Neurology Microglia in autism spectrum disorder

Figure 3. Treatment of autism spectrum disorder (ASD) through inflammatory and metabolic methods. Loss of omega-3 polyunsaturated fatty acids
(n-3 PUFAs) leads to changes in the lipid composition and oxygen-lipid characteristics of progeny microglia, ultimately polarizing microglia toward the
phagocytic phenotype and resulting in the secretion of neuroinflammatory cytokines that impair spine density and/or synaptic pruning, such as tumor
necrosis factor-α, interleukin (IL)-1β, and IL-6. Supplementation of n-3 PUFAs from weaning to adulthood improves ASD-like social deficits in a mouse
ASD model. Therefore, fish-oil capsules, containing n-3 fatty acids, with vitamin E supplements may be one of the key treatments for ASD patients. Shifting
the polarization from M1 to M2 has potential application using different kinds of drugs.
[70]
microglia produce a cascade of neuroinflammation neuropsychiatric symptoms associated with ASD . It has
cytokines that impair spine refinement or synaptic pruning. been suggested that p-Cresol, which is derived from Blautia
Supplementing with n-3 PUFAs from weaning to adulthood hydrogenotrophica and Clostridium spp., induces microglia
has led to significant improvements in ASD-like social activation and neuroinflammation . Recolonizing
[71]
deficits in ASD mouse models . Therefore, n-3 PUFAs patients with various microbiota or feeding SCFAs can
[69]
supplementation through fish-oil capsules containing sufficiently modulate microglia activation and alleviate
eicosapentaenoic acid (EPA) and docosahexaenoic acid ASD syndrome .
[72]
(DHA) with vitamin E may be a pivotal treatment for ASD
patients (Figure 3). 5. Challenges
4.3. Gut-brain axis and microglia ASD is a psychosocial condition that persists throughout
life. ASD patients experience social, speech, and behavioral
The gut-brain axis plays an intrinsic role in brain changes that can severely disrupt their daily life and work.
homeostasis. Microbiome-microglia crosstalk research has At present, there are many challenges in the treatment and
generated novel therapeutic approaches for ASD patients. prevention of ASD. Since the disorder cannot be cured, it
There have been reports of several microbiota metabolisms becomes a lifelong problem for patients. Furthermore, the
that impact the physiological characteristics of microglia. As detection of ASD is not feasible at an early stage or through
bacterial metabolites derived from microbial fermentation, pregnancy screening. The diagnosis of ASD mainly relies
the three main short-chain fatty acids (SCFAs) – propionate, on behavioral observations, and its symptoms cannot be
butyrate, and acetate – can be beneficial or detrimental for detected under the age of three, thus missing the critical
ASD treatments . Using antibiotics against Clostridia period of intervention.
[63]
and Bacteroidetes, the main producers of propionate
can help prevent the increased activation of microglia. MIA during pregnancy is one of the well-recognized
The treatment with butyrate or its byproducts generated mechanisms that have been successfully used to construct
by Clostridium butyricum promotes anti-inflammatory animal models. Altered cytokine expressions could
effects in microglia, contributing to the improvement of facilitate the identification of ASD phenotypes and provide

Volume 1 Issue 3 (2022) 7 https://doi.org/10.36922/an.v1i3.167