Metabolic biomarkers related to energy metabolism in Saudi autistic children O.A. Al-Mosalem a , A. El-Ansary a, ⁎ , O. Attas a , L. Al-Ayadhi b a Biochemistry Department, Science College, King Saud University, P.O Box 22452, Zip code 11495, Riyadh, Saudi Arabia b Autism Research and Treatment Centre, Physiology Department, College of Medicine, King Saud University, Saudi Arabia Received 6 January 2009; received in revised form 4 April 2009; accepted 11 April 2009 Available online 17 April 2009 Abstract Objectives: Energy metabolism is usually manipulated in many neurodegenerative diseases. Autism is considered a definable systemic disorder resulting in a number of diverse factors that may affect the brain development and functions both pre and post natal. The increased prevalence of autism will have enormous future public implications and has stimulated intense research into potential etiologic factors. This study aims to establish a connection between autism and the deterioration accompanied it, especially in the brain cognitive areas through a postulation of energy manipulation. Materials and methods: The biochemical changes in activities of enzymes and pathways that participate in the production of ATP as the most important high-energy compound needed by the human brain were measured in Saudi autistic children. Na + /K + ATPase, ectonucleotidases (NTPDases) (ADPase and ATPase) and creatine kinase (CK), were assessed in plasma of 30 Saudi autistic patients and compared to 30 age-matching control samples. In addition, adenosine mono, di and trinucleotides (ATP, ADP, and AMP) were measured calorimetrically in the red blood cells of both groups and the adenylate energy charge (AEC) was calculated. Moreover, lactate concentration in plasma of both groups was monitored. Results: The obtained data recorded 148.77% and 72.35% higher activities of Na + /K + ATPase and CK respectively in autistic patients which prove the impairment of energy metabolism in these children compared to age and sex matching healthy controls. While ADPase was significantly higher in autistic patients, ATPase were non-significantly elevated compared to control. In spite of the significant increase of Na + /K + ATPase activity in autistic patients, there was no significant difference in the levels of ATP, ADP, and AMP in both groups and the calculated AEC values were 0.814 ± 0.094 and 0.806 ± 0.081 for autistic and control groups respectively. The unchanged AEC value in autistic patients was easily correlated with the induced activity of CK and ADPase as two enzymes playing a critical role in the stabilization of AEC. Lactate as an important energy metabolite for the brain was significantly higher in autistic patients compared to control showing about 40% increase. Conclusion: The present study confirmed the impairment of energy metabolism in Saudi autistic patients which could be correlated to the oxidative stress previously recorded in the same investigated samples. The identification of biochemical markers related to autism would be advantageous for earlier clinical diagnosis and intervention. © 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Keywords: Autism; Energy metabolism; Na + /K + ATPase; Creatine kinase; Ectonucleotidases; Adenylate energy charge; Lactate Introduction Autism is a complex disorder that appears in the early years of childhood and is considered as a neuron developmental disorder. It is also accompanied with epileptic episodes at early age of life [1]. Autism is the most common form of pervasive developmental disorders (PDDs) and it affects boys more than girls by a ratio of 4:1 [2]. Prevalence studies have been done in several states of the USA, in the United Kingdom, Europe and Asia, estimated 3.4 of every 10,000 children of 3–10 years old will have autism [3]. This increased prevalence will have enormous future public health implications and has stimulated intense research into potential etiologic factors and candidate genes [4]. It is considered a definable systemic disorder resulting in a number of diverse factors that may affect the brain development and functions both pre and post natal [5]. Available online at www.sciencedirect.com Clinical Biochemistry 42 (2009) 949 – 957 ⁎ 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.2009.04.006