INFLAMMATION IS A KEY FACTOR IN CLINICAL MANIFESTATIONS OF AUTISM

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Analyses of a variety of clinical manifestations show that inflammation, directly or indirectly, is an etiopathogenetic factor underlying the clinical picture of autism. Hearing problems, including central auditory processing disorders, are inflammatory and associated with elevated expression of proinflammatory cytokines and microglial activation[1]. The Inflammation of the vestibular nerve can be followed by demyelination and loss of function[2]. Prolonged nasal inflammation can damage the epithelial and neuronal cells lining the olfactory mucosa and olfactory sensory neurons, leading to hyposmia or anosmia[3]. Neuroinflammation can affect both the eye and the CNS visual system leading to many vision dysfunctions[4]. The motor problems and some other autistic symptoms and signs in children with ASD, can be explained by inflammation in the cerebellum, a brain region responsible for motor control and higher cognitive functions used in language, social skills, and emotional regulation[5] [6]. In depression, inflammation is likely a critical disease modifier and promotor capable of increasing susceptibility to this neuropathology[7] and inflammatory cytokines are among the causative factors in the etiology of depression[8]. Evidence suggests that the gut microbiome plays a facilitating role in inflammation, stress response, anxiety, and depression[9]. The study of inflammation in fear- and anxiety-based disorders indicates that pro-inflammatory markers can directly modulate affective behavior[10]. The inflammatory diseases and a pro-inflammatory state have been associated with ADHD, bipolar disorder, and anxiety[11]. Evidence shows an interplay between immune dysregulation, inflammation, anxiety, and an altered acute neuroendocrine stress response that may exist in these disorders[12]. The data indicate that immune system and inflammatory processes are involved in obsessive-compulsive disorder (OCD)[13].

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[6] New Research Shows How Brain Inflammation in Children May Cause Neurological Disorders Such as Autism or Schizophrenia. (2023). University of Maryland School of Medicine. [25 April 2024] https://www.medschool.umaryland.edu/news/2023/new-research-shows-how-brain-inflammation-in-children-may-cause-neurological-disorders-such-as-autism-or-schizophrenia.html

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[8] Harsanyi S, Kupcova I, Danisovic L, Klein M. Selected Biomarkers of Depression: What Are the Effects of Cytokines and Inflammation? Int J Mol Sci. 2022 Dec 29;24(1):578. doi: 10.3390/ijms24010578. PMID: 36614020; PMCID: PMC9820159.

[9] Peirce JM, Alviña K. The role of inflammation and the gut microbiome in depression and anxiety. J Neurosci Res. 2019 Oct;97(10):1223-1241. doi: 10.1002/jnr.24476. Epub 2019 May 29. PMID: 31144383.

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[11] Saccaro LF, Schilliger Z, Perroud N, Piguet C. Inflammation, Anxiety, and Stress in Attention-Deficit/Hyperactivity Disorder. Biomedicines. 2021 Sep 24;9(10):1313. doi: 10.3390/biomedicines9101313. PMID: 34680430; PMCID: PMC8533349.

[12] Saccaro LF, Schilliger Z, Dayer A, Perroud N, Piguet C. Inflammation, anxiety, and stress in bipolar disorder and borderline personality disorder: A narrative review. Neurosci Biobehav Rev. 2021 Aug;127:184-192. doi: 10.1016/j.neubiorev.2021.04.017. Epub 2021 Apr 27. PMID: 33930472.

[13] Marazziti D, Palermo S, Arone A, Massa L, Parra E, Simoncini M, Martucci L, Beatino MF, Pozza A. Obsessive-Compulsive Disorder, PANDAS, and Tourette Syndrome: Immuno-inflammatory Disorders. Adv Exp Med Biol. 2023;1411:275-300. doi: 10.1007/978-981-19-7376-5_13. PMID: 36949315.