Activities of key glycolytic enzymes in the plasma of Saudi autistic patients

A El-Ansary¹, S Al-Daihan¹, A Al-Dabas¹, L Al-Ayadhi²

¹Biochemistry Department, Science College, ²Autism Research and Treatment Unit, Department of Physiology, Faculty of Medicine, King Saud University, Riyadh, Saudi Arabia

Objective: Measurement of plasma levels of lactate, lactate oxidase (LOX), pyruvate kinase (PK), and hexokinase (HK) as possible glycolytic parameters to assess brain damage in autistic patients.

Design and methods: Plasmatic levels of lactate, LOX, PK, and HK were determined in 20 autistic children aged 3–15 years and 20 age-matching healthy control subjects.

Results: Plasmatic levels of lactate and LOX were significantly higher in autistic patients compared to healthy subjects and that of PK and HK were significantly lower in these patients as compared to controls. This could reflect the impaired metabolism of astrocytes, the brain cells responsible for the production and provision of lactate, as the primary metabolic fuel for neurons.

Conclusion: Remarkably different levels of plasma glycolytic parameters were recorded in Saudi autistic patients. This could be correlated to the impairment of energy metabolism, glutathione depletion, and lead intoxication previously detected in the same investigated samples. The identification of biochemical markers related to autism would be advantageous for earlier clinical diagnosis and intervention.

Keywords: autism, glycolysis, lactate, lactate oxidase, pyruvate kinase, hexokinase