Evaluation of serum galectin-1, galectin-3, galectin-8 and galectin-9 levels in children with attention deficit hyperactivity disorder

Objective: Attention Deficit Hyperactivity Disorder (ADHD) is the most common neurodevelopmental disorder in childhood. While genetic and environmental factors are known to play a role in its etiology, the exact etiological causes have not been fully elucidated. Recent research suggests that neuroinflammation and immune system dysfunction may play a role in the pathophysiology of ADHD. Galectins are lectin-like proteins that particularly play a role in cellular adhesion and signal transduction. Galectin-1, galectin-3, galectin-8, and galectin-9 are particularly known to be associated with the Central Nervous System (CNS). Studies have shown that there are changes in galectin levels in neurodevelopmental disorders. Although no studies have been found investigating the relationship between ADHD and galectin-1, galectin-8, or galectin-9 levels, there are very few studies examining the relationship with galectin-3. This study aims to compare serum levels of galectin-1, galectin-3, galectin-8, and galectin-9 in children and adolescents diagnosed with ADHD with healthy controls and to explore the possible relationships between ADHD severity, clinical features, and the serum levels of these galectins. Method: The study was conducted between December 2023 and July 2024 at the Department of Child and Adolescent Psychiatry, Faculty of Medicine, Karadeniz Technical University.The clinical evaluation process was based on the DSM-5 diagnostic criteria and semi-structured interviews with the Turkish adaptation of the Affective Disorders and Schizophrenia Interview Schedule for School-Age Children-Present and Lifetime Version (K-SADS-PL). Accordingly, 45 children who were diagnosed with ADHD, agreed to participate in the study and met the eligibility criteria were determined as the case group; 40 children matched with these children in terms of gender and age were included in the control group. The Conners' Parent Rating Scale-Revised Short Form (CPRS-R: S) and the Conners' Teacher Rating Scale (CTRS-28) were used to assess the symptoms and the severity of ADHD symptoms in the ADHD group. In the control group, only the CPRS-R: S was used. Both groups were administered the Wechsler Intelligence Scale for Children-Revised (WISC-R). Serum galectin-1, galectin-3, galectin-8 and galectin-9 levels were measured by Enzyme Linked Immuno Sorbent Assay (ELISA) method in the case and control groups. Results: Serum levels of galectin-1 and galectin-9 were statistically significantly higher (p < 0.001; p < 0.001) and galectin-8 was statistically significantly lower (p < 0.001) in the ADHD group compared to the control group. However, no significant difference was found between ADHD and control groups in terms of galectin-3 serum levels (p = 0.812).While there was a moderate and statistically significant negative correlation between serum galectin-9 level and CPRS-R: S total score (p = 0.007), no correlation was found between serum galectin-1, galectin-3 and galectin-8 levels and ADHD severity (p = 0.386; 0.223; 0.217). Conclusion: The data in this study indicate that significant differences in serum galectin-1, galectin-8 and galectin-9 levels may be related to the etiopathogenesis of ADHD.Further studies are needed to evaluate galectin-1, galectin-3, galectin-8 and galectin-9 as potential biomarkers in the diagnosis and etiology of ADHD. Keywords: Attention deficit hyperactivity disorder, galectin-1, galectin-3, galectin-8, galectin-9, neuroinflammation