Evaluation of plasma GRP78 levels in patients with autism spectrum disorder

Abstract

Objective: The role of endoplasmic reticulum (ER) stress in the pathogenesis of autism spectrum disorder (ASD) has been previously reported in both experimental and postmortem studies. However, no circulating marker of ER stress has been identified so far in ASD patients. In the present study, the plasma level of glucose-regulated protein 78 (GRP78) was investigated in ASD patients as a potential marker for ER stress. Method: Plasma samples taken from healthy control subjects (n=26) and ASD patients (n=29) were used to evaluate circulating GRP78 levels. Plasma GRP78 concentrations were measured by ELISA. The severity of the disease in the ASD group was determined by the childhood autism rating scale. Results: There was no significant difference between the median values of plasma GRP78 levels in ASD (12.40) and healthy control groups (11.11) (p<0.218). Plasma GRP78 concentration was 12.81 +/- 4.90 ng/mL in the ASD group and was not significantly different from the control values (11.12 +/- 3.83 ng/mL). Conclusion: Although ER stress was associated with ASD, our results showed that plasma levels of GRP78 did not change in ASD patients. Our results suggest that GRP78 is not an appropriate circulatory marker to evaluate ER stress in ASD patients.