Mitochondrial dysfunction in autism spectrum disorders: a systematic review and meta-analysis

A comprehensive literature search was performed to collate evidence of mitochondrial dysfunction in autism spectrum disorders (ASDs) with two primary objectives. First, features of mitochondrial dysfunction in the general population of children with ASD were identified. Second, characteristics of mitochondrial dysfunction in children with ASD and concomitant mitochondrial disease (MD) were compared with published literature of two general populations: ASD children without MD, and non-ASD children with MD. The prevalence of MD in the general population of ASD was 5.0% (95% confidence interval 3.2, 6.9%), much higher than found in the general population (∼0.01%). The prevalence of abnormal biomarker values of mitochondrial dysfunction was high in ASD, much higher than the prevalence of MD. Variances and mean values of many mitochondrial biomarkers (lactate, pyruvate, carnitine and ubiquinone) were significantly different between ASD and controls. Some markers correlated with ASD severity. Neuroimaging, in vitro and post-mortem brain studies were consistent with an elevated prevalence of mitochondrial dysfunction in ASD. Taken together, these findings suggest children with ASD have a spectrum of mitochondrial dysfunction of differing severity. Eighteen publications representing a total of 112 children with ASD and MD (ASD/MD) were identified. The prevalence of developmental regression (52%), seizures (41%), motor delay (51%), gastrointestinal abnormalities (74%), female gender (39%), and elevated lactate (78%) and pyruvate (45%) was significantly higher in ASD/MD compared with the general ASD population. The prevalence of many of these abnormalities was similar to the general population of children with MD, suggesting that ASD/MD represents a distinct subgroup of children with MD. Most ASD/MD cases (79%) were not associated with genetic abnormalities, raising the possibility of secondary mitochondrial dysfunction. Treatment studies for ASD/MD were limited, although improvements were noted in some studies with carnitine, co-enzyme Q10 and B-vitamins. Many studies suffered from limitations, including small sample sizes, referral or publication biases, and variability in protocols for selecting children for MD workup, collecting mitochondrial biomarkers and defining MD. Overall, this evidence supports the notion that mitochondrial dysfunction is associated with ASD. Additional studies are needed to further define the role of mitochondrial dysfunction in ASD

Adverse Effects of Selected Markers on the Metabolic and Endocrine Profiles of Obese Women With and Without PCOS

The aim of the present study, is to investigate the influence of obesity, with and without polycystic ovarian syndrome (PCOS), on the levels of kisspeptin, vitamin D (Vit D), and vascular endothelial growth factor (VEGF) and to explore the relationship between these parameters and endocrine and metabolic variables. The study group included 126 obese Saudi females. Of these 63 were suffering from PCOS while the rest were normo-ovulatory obese women (non-PCOS obese). In the obese PCOS, VEGF was almost four times as high as in the non-PCOS obese, while kisspeptin and Vit D did not differ. A highly significant elevation was recorded in the waist/hip (WHR), cholesterol, LDL-C, fasting glucose, LH, LH/FSH ratio, estradiol (E2), and testosterone, while hip circumference, leptin, progesterone, and sex hormone binding globulin (SHBG) were lower in the obese PCOS subjects. BMI, HDL-C, ghrelin, insulin, and FSH levels did not differ significantly between the two groups. The obese PCOS had the same level of insulin resistance as the non-PCOS group, as judged by QUICK Index. Correlation studies showed a significant negative correlation between kisspeptin and glucose and LH levels, and a positive correlation with LH/FSH ratio in obese PCOS while in the non-PCOS obese, the kisspeptin correlated positively with glucose, and there was no correlation with LH or LH/FSH. VEGF negatively correlated with FSH and positively with LH/FSH ratio in the non-PCOS obese but this was lost in the obese PCOS. PCOS had no effect on the correlation between Vit D and all studied parameters. Multiple regression analysis showed triglyceride as predictor variable for kisspeptin as a dependent variable, while, leptin is a predictor variable for VEGF as a dependent variable. ROC studies showed the highest sensitivity and specificity for VEGF (AOC=1.00), followed by LH/FSH ratio (AOC=0.979). In conclusion, our study shows that PCOS results in significant elevation of VEGF in obese females, while kisspeptin and Vit D levels are not affected. It also leads to elevation in several of the lipid and hormonal abnormalities in the obese females. In addition, PCOS influences relationship between Kisspeptin and VEGF and some parameters such as glucose, LH or FSH and LH/FSH ratio in obese females, but does not affect Vit D relationship with other parameter.</jats:p

Relationship between absolute and relative ratios of glutamate, glutamine and GABA and severity of autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental pathology characterized by an impairment in social interaction, communication difficulties, and repetitive behaviors. Glutamate signaling abnormalities are thought to be considered as major etiological mechanisms leading to ASD. The search for amino-acidic catabolytes related to glutamate in patients with different levels of ASD might help current research to clarify the mechanisms underlying glutamate signaling and its disorders, particularly in relation to ASD. In the present study, plasma levels of the amino acids and their derivatives glutamate, glutamine, and γ-aminobutyric acid (GABA), associated with their relative ratios, were evaluated using an enzyme-linked immunosorbent assay (ELISA) technique in 40 male children with ASD and in 38 age- and gender-matched neurotypical health controls. The Social Responsiveness Scale (SRS) was used to evaluate social cognition, and the Childhood Autism Rating Scale (CARS) was used to assess subjects' behaviors. Children with ASD exhibited a significant elevation of plasma GABA and glutamate/glutamine ratio, as well as significantly lower levels of plasma glutamine and glutamate/GABA ratios compared to controls. No significant correlation was found between glutamate levels and the severity of autism, measured by CARS and SRS. In receiver operating characteristic (ROC) curve analysis, the area under the curve for GABA compared to other parameters was close to one, indicating its potential use as a biomarker. Glutamine appeared as the best predictive prognostic markers in the present study. The results of the present study indicate a disturbed balance between GABAergic and glutamatergic neurotransmission in ASD. The study also indicates that an increased plasma level of GABA can be potentially used as an early diagnostic biomarker for ASD