Metabolic biomarkers related to oxidative stress and antioxidant status in Saudi autistic children Y. Al-Gadani a , A. El-Ansary a, ⁎ , O. Attas a , L. Al-Ayadhi b a Biochemistry Department, Science College, King Saud University, PO Box 22452, Zip code 11495, Riyadh, Saudi Arabia b Autism Research and Treatment Unit, Department of Physiology, Faculty of Medicine King Saud University, Riyadh, Saudi Arabia Received 29 December 2008; received in revised form 23 February 2009; accepted 11 March 2009 Available online 21 March 2009 Abstract Objective: Measurement of oxidative stress and antioxidant-related parameters (enzymatic and non-enzymatic) in Saudi autistic children. Design and methods: 30 autistic children (22 males and 8 females) aged 3–15 years (25/30 of these were below 8 years old), and 30 healthy children as control group were included in this study. Levels of lipid peroxides, vitamin E, vitamin C, glutathione together with enzymatic activities of glutathione peroxidase (GSH-Px), and catalase were determined in plasma while superoxide dismutase (SOD was measured in red blood cells of both groups. Results: Lipid peroxidation was found to be significantly higher in autistic compared to control Saudi children. On the other hand, vitamin E and glutathione were remarkably lower in autistic patients while vitamin C shows non-significant lower values. Regarding the enzymatic antioxidants, both glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were significantly higher in autistic compared to control while catalase recorded more or less similar activities in both groups. Conclusion: Saudi autistic children are under H 2 O 2 stress due to GSH depletion, over expression of SOD together with the unchanged catalase enzyme. This could be helpful in the early diagnosis of young autistic patients and suggesting the possibility of antioxidant supplementation for the early intervention with autistic children. © 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Keywords: Autism; Oxidative stress; Antioxidant status; Lipid peroxides; Vitamin E; Vitamin C; Glutathione; Glutathione peroxidase; Catalase; Superoxide dismutase Introduction Autism is a severe nuerodevelpomental disorder with onset prior to 3 years of age [1]. It is a heterogeneous disorder, both etiologically and phenotypically. Several factors have been implicated in the etiology of autism, including genetic, environmental, and autoimmune factors [2,3]. In addition to behavioral impairment, autistic persons have a high prevalence of gastrointestinal disease and dysbiosis [4], autoimmune disease [5], and mental retardation [6]. Autism also affects many more males than females, occurring at ratio of 4:1. The prevalence of autism has increased over the last several decades, partly as a result of a broadening of diagnostic criteria and greater awareness among health professionals, but it is difficult to ascertain to what degree these factors account for the increase. Prevalence studies have been done in several states of the USA, in the United Kingdom, Europe, and Asia, estimating 3.4 of every 10,000 children of 3–10 years old will have autism [7]. Prevalence of autistic spectrum disorders in Saudi Arabia is 6:1000 (unpublished data, personal communication) [8], and a male to female ratio of 4.2:1 [9]. This increased prevalence will have enormous future public health implications and has stimulated intense research into potential etiologic factors. Despite numerous reports suggesting a high rate of inhe- ritance, no specific single genes have been identified that are more than risk factors [10,11]. Prenatal environmental factors, such as obstetrical sub optimality, alcohol exposure and intrauterine infections, have also been reported to influence the occurrence of autism [12]. One additional mechanism that has received serious consideration is an abnormality of immune Available online at www.sciencedirect.com Clinical Biochemistry 42 (2009) 1032 – 1040 ⁎ Corresponding author. E-mail addresses: afafelansary@yahoo.com, elansary@ksu.edu.sa (A. El-Ansary). 0009-9120/$ - see front matter © 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2009.03.011