Agmatine ameliorates valproic acid-induced depletion of parvalbumin-positive neuron

Autism spectrum disorder (ASD) is a widespread neurodevelopmental disorder with unknown etiology. Dysfunction of several brain areas including the prefrontal cortex (PFC), hippocampus, and cerebellum is involved in cognitive and behavioral deficits associated with ASD. Several studies have reported a reduction in the number of parvalbumin-immunoreactive (PV+) neurons in brain areas of ASD patients and animal models such as a shank mutant mouse model and rodents receiving fetal valproic acid (VPA) administration. Developing therapeutic interventions that restore PV interneurons can be the future therapeutic approach to ASD. The present study examined the possible effect of agmatine (AG), an endogenous NMDA antagonist, on the number of PV+ neurons in a VPA animal model of autism. The therapeutic effects of AG in ameliorating ASD-like behaviors were previously reported in VPA rats. AG was gavaged at dosages of 0.001, 0.01, and 0.1 mg/kg from gestational day (GD) 6.5 to 18.5, and the number of PV interneurons was analyzed by immunohistochemistry in the 1-month-old rats. Prenatal VPA (GD 12.5) or AG led to a decrease of PV neurons in the PFC, Cornu ammonia (CA1), and molecular layers (MLs) of the cerebellum. However, exposure to AG restored the PV population induced by VPA. AG may modify underlying neuronal mechanisms resulting in the increased survival or restoration of the PV population.

Autistic-like behaviors are attenuated by agmatine consumption during pregnancy: Assessment of oxidative stress profile and histopathological changes in the prefrontal cortex and CA1 region of the hippocampus

Objectives

Due to the crucial role of polyamines during fetal growth and development, we aimed to determine the effect of prenatal administration of agmatine, an endogenous active metabolite of arginine, and a nutritional supplement, on autistic-like behaviors, oxidative-anti-oxidative profile, and histopathological changes of the prefrontal cortex (PFC) and CA1 area of the hippocampus in valproic acid (VPA) model of autism in male rats.

Materials and Methods

VPA was injected intraperitoneally on embryonic days (ED) 12.5, and the pregnant rats were gavaged with agmatine between E6.5 to E18.5 (13 days), at doses of 0.001, 0.01, and 0.1 mg/kg. The autism-like behaviors and memory of male pups were analyzed via open-field, three-chamber, and novel object recognition tests. Serum oxidative stress and the histological changes in the PFC and CA1 were assessed at the end of the study.

Results

The results suggest that prenatal agmatine reduced autistic-like behaviors by decreasing cell loss in CA1 and PFC. We observed no alterations in superoxide dismutase (SOD) level and total anti-oxidant capacity (TAC) between groups. VPA decreased catalase (CAT) activities, while agmatine decreased malondialdehyde (MDA) activity.

Conclusion

Overall, this investigation suggests that agmatine may be a potential candidate for the early treatment and even prevention of appearance of autism symptoms.

DNMT3B -149 C>T and -579 G>T Polymorphisms and Risk of Gastric and Colorectal Cancer: a Meta-analysis

BACKGROUND

Numerous studies have investigated associations of DNA methyltransferase (DNMT) -149 C>T and -579 G>T polymorphisms with gastric cancer (GC) and colorectal cancer (CRC) susceptibility; however, the findings are inconsistent prompting the present meta-analysis.

MATERIALS AND METHODS

Related studies were identified from PubMed, Google scholar, and SID until 10 October 2015. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations.

RESULTS

Eleven studies were included based on the search criteria for CRC and GC related to the DNMT3B 149 C>T (3,353 cases and 4,936 controls) and DNMT3B 579 G>T (1,387 cases and 2,064 controls) polymorphisms. There was no significant association overall between DNMT3B -149 and 579 polymorphisms and the risk of cancer. In the stratified analysis by cancer type, DNMT3B 579G>T polymorphism was associated with the risk of CRC and GC. While the DNMT3B -149C/T polymorphism was related with a significantly increased risk of CRC in two tested models, dominant (GG+GT vs. TT: OR 0.51, 95 % CI 0.38-0.69; P = 0.00, Pheterogeneity=0.69, I2= 0 %) and heterozygote (GT vs. TT: OR 0.50, 95 % CI 0.37-0.69; P=0.00, Pheterogeneity=0.41, I2= 0 %), no evidence of any association with GC risk was observed as in the pooled analyses.

CONCLUSIONS

More studies are needed to assess associations of DNMT3B -149C/T and DNMT3B 579G>T polymorphisms with cancer in different ethnicities with large population sizes to generate comprehensive conclusions.