Abstracts

Rationale:
Individuals who experience recurrent spontaneous seizures are at a high risk for bone fractures and an increased likelihood of a comorbid diagnosis of Autism spectrum disorder. Additionally, individuals with epilepsy could have vitamin D deficiencies, as common antiepileptic drugs have been shown to decrease vitamin D levels. Previous work in our lab has shown that neural subset-specific (NS) Pten knockout (KO) mice, a mouse model of cortical dysplasia, has an epileptic phenotype and displays autistic-like behaviors. The NS-Pten KO mouse also has a significant reduction in bone mineral density (BMD) in the proximal tibial metaphysis and midshaft compared to WT mice. Therefore, this model will allow us to determine treatments that could reverse autistic-like behaviors and bone phenotypes.
Method:
Beginning at 4 weeks of age, mice received either a vitamin D enriched chow equivalent to 20,000 IU/kg or remained on the same diet that contained approximately 1.5 IU/g of vitamin D and remained on this diet for a total of 5 weeks. In the 3rd week of dietary manipulation, mice began behavioral testing as follows: Open Field, Elevated Plus Maze, Nose Poke Assay, Social Partition, Delayed Fear Conditioning. After behavioral testing, mice were sacrificed, and tissue was collected. A vivaCT40 microCT scanner at 10.5 μm voxel resolution was used to measure the proximal and mid diaphysis of the mouse femur. Analysis of trabecular parameters in the tibial metaphysis and cortical parameters in the tibial midshaft were also performed.
Results:
In the open field, loss of NS-Pten resulted in reduced total distance compared to WT animals (p < 0.05), and this effect was attenuated in males by exposure to vitamin D (p > 0.05). Vitamin D also decreased anxiety in the EPM (p < 0.05). NS-Pten KO animals exhibited a reduction in sociability (p < 0.001), however in male wildtype mice, vitamin D increased sociability (p < 0.05). There was a significant effect of genotype and death (p < 0.01) and between diet and death (p < 0.01), finding that only CTL KO animals died. In addition, KO animals had a reduction in BMD (p < 0.01) and an increase in trabecular volume (p < 0.001) in the proximal metaphysis compared to WT animals. Interestingly, this effect was not rescued by exposure to vitamin D (p > 0.05).
Conclusion:
Our findings suggest that a diet enriched in vitamin D could provide therapeutic benefit by attenuating behavioral impairments observed in NS-Pten KO mice. Specifically, the current study found that a vitamin D enriched diet attenuated activity alterations, reduced anxiety levels in male KOs, and increased sociability in WT male animals. Additionally, there was a significant effect on percent survivability as we found a mortality rate of about 26% in KO animals on the control diet, whereas none of the KO animals on the vitamin D enriched diet died during testing. Vitamin D has been shown in clinical studies aid in numerous health benefits including seizure control as well as targeting some behavioral abnormalities. This current study adds to the growing evidence of the importance of vitamin D in brain development and function and could be considered as a supplemental therapeutic treatment.
Funding:
:National Institutes of Health (NIH) [Grant Number: NS088776]