Relationship between Sonic hedgehog protein, brain-derived neurotrophic factor and oxidative stress in autism spectrum disorders

Abstract

The etiology of autism spectrum disorders (ASD) is not well known but oxidative stress has been suggested to play a pathological role. We report here that the serum levels of Sonic hedgehog (SHH) protein and brain-derived neurotrophic factor (BDNF) might be linked to oxidative stress in ASD. By using the whole blood or polymorphonuclear leukocytes, we demonstrated that autistic children produced a significantly higher level of oxygen free radicals (OFR). In addition, we found significantly higher levels of serum SHH protein in children with mild as well as severe form of autism. We also found that the serum level of BDNF was significantly reduced in autistic children with mild form of the disorder but not with severe form of the disorder. Our findings are the first to report a correlation between SHH, BDNF and OFR in autistic children, suggesting a pathological role of oxidative stress and SHH in autism spectrum disorders.

Fig. 1

Serum levels of BDNF in control and autistic children. BDNF in mild and severe ASD, compared to control subject. BDNF serum level were significantly high in mild but not severe autistic children compared to age and sex matched subjects 442 ± 20 (pg/ml), 290 ± 90 (pg/ml), P < 0.05), respectively

Fig. 2

Serum levels of Sonic hedgehog protein in control and autistic children. Highly statistically significant Sonic hedgehog serum level in mild and severe autism

Fig. 3

Relationship between SHH serum level and CARS score. Serum Level of SHH protein was positively correlated with the severity of autism (r = 0.69)