Abstracts

Rationale: In Sturge-Weber syndrome (SWS), seizures affect 75% to 90% of cases, and approximately 60% lead to refractory epilepsy. However, the mechanism by which SWS leads to epilepsy is unclear. In our laboratory, from an analysis of intracranial brain wave data performed on SWS, we have reported the possibility that ischemia in the cerebral cortex directly below a pia mater angioma can induce epilepsy. In the present research, we performed immunohistostaining of SWS brain tissue obtained during surgical procedures for refractory epilepsy in an attempt to aid the search for the mechanism by which SWS causes epilepsy. Methods: The subjects were 4 cases of SWS accompanied by refractory epilepsy (ages 1.8 to 4 years), and in all the cases the seizure symptoms were motionless staring and respiratory distress. With regard to the surgical treatment, if the location of the angioma was localized to the temporal lobe, parietal lobe, or occipital lobe then a posterior quadrantectomy was performed, but if it had advanced to the frontal lobe then a frontal disconnection or hemisphere disconnection was also performed. We used paraffin to fix the brain tissue that had been excised in parts from the focal point of the epilepsy during the disconnection procedures and performed pathology analysis with immunohistostaining. For the immunohistostaining we used MAP2, GFAP, Glut5, HMGB1, TLR4, and ssDNA. Results: The seizure control effect after surgical treatment was grade 1 in the Engel classification. In the evaluation of immunostaining, for MAP2 staining the immunostaining of dendrites showed a tendency to decrease, there was an eosinophilic change in neuron cytoplasm, and pyknotic neurons were found. For activated microglia and TLR4 staining, the finding was that immunoreaction was found such as in glia cells and interneurons, so this finding suggests the involvement of inflammation mediators (the HGMG1-TLR4 pathway). In cases of greater age at the time of surgery stronger gliosis was found, as well as a tendency for remarkable proliferation of reactive astrocytes. Conclusions: Many pyknotic neurons were found in the SWS pathology findings, and we infer that mechanisms for conferring the ability to cause epilepsy may include the involvement of ischemic anemic infarction as well as inflammation mediators, inducing changes in neural network excitability. Funding: None