title: Decreased total antioxidant capacity has a larger effect size than increased oxidant levels in urine in individuals with autism spectrum disorder.
abstract: Oxidant/antioxidant imbalance may contribute to the pathophysiology of autism spectrum disorder (ASD). We assayed urinary levels of oxidative stress related biomarkers, hexanoyl-lysine (HEL), total antioxidant capacity (TAOC), the DNA methylation biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG), and plasma levels of superoxide dismutase (SOD), which is major antioxidant enzyme. We examined the relationship between these four biomarkers and social responsiveness in 20 individuals with ASD and in 11 healthy controls. The sex (ASD group, 7/13 vs. control group, 4/7) and age distributions (ASD group, 10.7 ± 5.0 years vs. control group, 14.7 ± 6.3 years) were not significantly different between the groups. Social responsiveness was assessed using the social responsiveness scale (SRS). We used standardized regression coefficients to measure the effect size. The ASD group exhibited significantly lower urinary TAOC levels and significantly elevated urinary HEL levels than the control group. Urinary 8-OHdG levels and plasma SOD levels were not significantly different between the groups. The ASD group showed significantly higher SRS scores than the control group. Plasma SOD levels correlated significantly with urinary TAOC levels. Standardized regression coefficients revealed that TAOC levels had a larger effect size than HEL levels in urine. This study firstly reveals that an imbalance between urinary HEL and TAOC levels in favor of urinary TAOC levels may contribute to impaired social responsiveness in individuals with ASD. Plasma SOD levels may also affect urinary TAOC levels.
authors.affiliation: Department of Pediatrics, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi, 321-0293, Japan. yui16@bell.ocn.ne.jp.|Department of Drug Evaluation and Informatics, School of Pharmaceutical Science, University of Shizuoka, Shizuoka, 422-8526, Japan. yui16@bell.ocn.ne.jp.
authors.forename: Kunio
authors.initials: K
authors.lastname: Yui
authors.affiliation: Department of Pediatrics, Tokyo Metropolitan Fuchu Medical Center for the Disabled, Tokyo, 183-8553, Japan.
authors.forename: Nasoyuki
authors.initials: N
authors.lastname: Tanuma
authors.affiliation: Department of Drug Evaluation and Informatics, School of Pharmaceutical Science, University of Shizuoka, Shizuoka, 422-8526, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Drug Evaluation and Informatics, School of Pharmaceutical Science, University of Shizuoka, Shizuoka, 422-8526, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kawasaki
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000293:Adolescent; D000975:Antioxidants / Q000032:analysis*; D000067877:Autism Spectrum Disorder / Q000523:psychology / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D002648:Child; D002675:Child, Preschool; D003849:Deoxyguanosine / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D008297:Male; D016877:Oxidants; D018384:Oxidative Stress; D012919:Social Behavior
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D016877:Oxidants; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine
keywords: Autism spectrum disorder; Endogenous antioxidant capacity; HEL and 8-OHdG levels; Potential effects size; Standardized regression coefficients; Total antioxidant power in urine