Individuals with autism have higher 8-Iso-PGF2α levels than controls, but no correlation with quantitative assay of Paraoxonase 1 serum levels

NMR-Based Metabolomics of Rat Hippocampus, Serum, and Urine in Two Models of Autism

Autism spectrum disorders (ASDs) are increasingly diagnosed as developmental disabilities of unclear etiology related to genetic, epigenetic, or environmental factors. The diagnosis of ASD in children is based on the recognition of typical behavioral symptoms, while no reliable biomarkers are available. Rats in whom ASD-like symptoms are due to maternal administration of the teratogenic drugs valproate or thalidomide on critical day 11 of pregnancy are widely used models in autism research. The present studies, aimed at detecting changes in the levels of hydrophilic and hydrophobic metabolites, were carried out on 1-month-old rats belonging to the abovementioned two ASD models and on a control group. Analysis of both hydrophilic and hydrophobic metabolite levels gives a broader view of possible mechanisms involved in the pathogenesis of autism. Hippocampal proton magnetic resonance (MRS) spectroscopy and ex vivo nuclear magnetic resonance (NMR) analysis of serum and urine samples were used. The results were analyzed using advanced statistical tests. Both the results of our present MRS studies of the hippocampus and of the NMR studies of body fluids in both ASD models, particularly from the THAL model, appeared to be consistent with previously published NMR results of hippocampal homogenates and data from the literature on autistic children. We detected symptoms of disturbances in neurotransmitter metabolism, energy deficit, and oxidative stress, as well as intestinal malfunction, which shed light on the pathogenesis of ASD and could be used for diagnostic purposes. These results confirm the usefulness of the noninvasive techniques used in ASD studies.

The association of stem cell factor and soluble c-Kit (s-cKit) receptor serum concentrations with the severity and risk prediction of autism spectrum disorders

S tem cell factor (SCF) and its receptor (c-kit) signaling play important role in normal brain physiology including neurogenesis, synapse formation and spatial learning function of the hippocampal region of the brain. Autism spectrum disorder (ASD) is believed to result from abnormal development of neuronal networks and synaptic function. The aim of this study was to evaluate the SCF and its soluble receptor (s-ckit) serum concentrations in ASD. We also studied the serum SCF and s-ckit concentration with the severity of ASD (Levels 1-3; Mild, Moderate and severe, respectively). Ninety five patients with ASD (Mild; n=33, Moderate; n=32 and severe; n=30) and 82 normal controls age matched were included in this study. The serum concentration of SCF and s-ckit were measured by enzyme-linked immunosorbent assay (ELISA). The SCF serum concentration in control subjects was 3.45±1.06 ng/ml and in ASD was 3.41±0.92 ng/ml (P=0.88). The serum levels of s-ckit in control and ASD groups were 56.82±13.22 ng/ml and 67.11±12.00, respectively (P=001). We have also studied serum SCF and s-ckit concentrations with the severity of ASD. The serum concentration of SCF in mild, moderate and severe ASD groups was 3.45±0.93, 3.4±0.87 and 3.43±0.98 ng/ml, respectively (P>0.05) and for s-ckit was 48.77±9.28, 61.66±12.18 and 93.11±14.81ng/ml, respectively (P<0.05). The result of this study suggests that serum s-cKit concentrations may provide a reliable and practical indicator of ASD and positively correlated with disease severity. It is also concluded that s-cKit might be involved in the pathophysiology of ASD.

Developmental and social deficits and enhanced sensitivity to prenatal chlorpyrifos in PON1-/- mouse pups and adults

The levels and activity of the enzyme paraoxonase 1 affect the vulnerability to the teratogenic effects of organophosphate pesticides. Mutant mice lacking the gene for paraoxonase1 (PON1^-/-) are more susceptible to the toxic effects of chlorpyrifos, and were hypothesized to be more vulnerable to social behavior deficits induced by exposure to chlorpyrifos during gestation. Three experiments were performed comparing PON1^-/- mice to PON1^+/+ mice born to dams treated with 0.5 mg/kg chlorpyrifos or cornoil vehicle on gestational days 12–15. Chlofpyrifos-exposed male PON1^-/- mouse pups had delayed development of reflexes in in the first experiment. In the second experiment, adult male and female PON1^-/- mice and the female PON1^+/+ mice all displayed lower social preference than the male vehicle-treated PON1^+/+ mice. The PON1^-/- mice and the female PON1^+/+ mice displayed lower social preference compared to the PON1^+/+ male mice. Male adult mice that had been exposed in utero to chlorpyrifos showed less conditioned social preference regardless of genotype. In the third study, the delayed reflex development was replicated in male and female PON1^-/- mice, but chlorpyrifos did not augment this effect. Nest Odor Preference, a test of early social attachment to dam and siblings, was lower in PON1^-/- mouse pups compared to PON1^+/+ pups. This study shows for the first time that PON1^-/- mice have a behavioral phenotype that indicates impaired reflex development and social behavior. Chlorpyrifos exposure during gestation tended to augment some of these effects.