BDNF content and catalase activity in the blood of children with autism spectrum disorders

BACKGROUND: With the increasing prevalence of autism spectrum disorders worldwide, it is relevant to study the mechanisms contributing to their development and progression. The participation of brain-derived neurotrophic factor and oxidative stress in the pathogenesis of the disease is considered, however, their role in this process remains unclear. The relationship between BDNF levels and oxidative stress in the blood of patients with autism spectrum disorders has not been studied. AIM: The aim was to evaluate the content of brain neurotrophic factor, BDNF, and catalase, an antioxidant defense enzyme, in children with various clinical forms of autism spectrum disorders. MATERIALS AND METHODS: BDNF content and catalase activity were assessed in the blood plasma of 78 children with autism spectrum disorders, including 41 patients with childhood autism, 19 children with atypical autism, 6 patients with Aspergers syndrome, and 12 patients with other general developmental disorders (with elements of autism). The control group consisted of 20 conditionally healthy children. The diagnosis was established in accordance with the ICD-10. The severity of disorders was determined using the Childhood Autism Rating Scale. The content of BDNF was evaluated using the method of enzyme immunoassay, catalase activity was determined by colorimetric method. RESULTS: The content of BDNF in blood plasma was reduced in children with autism spectrum disorders compared to its levels in control group subjects. BDNF levels depended on the clinical form of the disease: the content of BDNF was reduced in patients with childhood autism, atypical autism, Aspergers syndrome compared to control group subjects; in patients with atypical autism it is lower than in patients with childhood autism; BDNF levels in the group of patients with other general developmental disorders and in control group did not differ. The content of BDNF did not depend on gender, age and severity of autism spectrum disorders. A negative correlation was found between BDNF levels and the age of control group children. There were no differences in the activity of catalase in the blood of children with autism spectrum disorders and in control group. A positive correlation was found between BDNF levels and catalase activity in children with autism spectrum disorders and control group subjects. CONCLUSIONS: A decrease in the content of BDNF in the blood of children with autism spectrum disorders was revealed. Neurotrophin content differed in children with separate clinical forms of the disease. To varying degrees the decrease in BDNF levels in patients with childhood autism, atypical autism, Aspergers syndrome and the absence of changes in patients with other general developmental disorders compared with controls could be associated with a different contribution of neurotrophin to the pathogenesis of clinical forms of autism spectrum disorders. In children with autism spectrum disorders, there were no age-related changes in neurotrophin levels, while in healthy children a negative correlation was found between the content of BDNF and age. The absence of changes in the activity of catalase in the blood of children with autism spectrum disorders indicated the safety of the antioxidant defense system in terms of this indicator. The positive correlation between BDNF levels and catalase activity in the blood of patients with autism spectrum disorders and control group subjects reflected the protective role of neurotrophin from the damaging effects of oxidative stress.