Increased activation of Iba1+ microglia in pediatric epilepsy patients with Rasmussen's encephalitis compared with cortical dysplasia and tuberous sclerosis complex

Abstract

Microgliosis is prominent in Rasmussen's encephalitis (RE), a disease with severe seizure activity. However, it is unclear if microglial activation is similar with different histopathologic substrates. Iba1-immunolabelled microglial activation was assessed in neocortex from pediatric epilepsy surgery patients with RE (n=8), cortical dysplasia (CD; n=6) and tuberous sclerosis complex (TSC; n=6). Microglial reactivity was increased, in severely affected RE areas (29% labeling) compared with minimally affected areas of RE cases (15%) and cases of TSC (14%) and CD (12%). There was no qualitative association of Iba1 immunolabelling with the presence of CD8 + cytotoxic T-cells and no statistical association with clinical epilepsy variables, such as seizure duration or frequency. Iba1 appears to be an excellent marker for detecting extensive microglial activation in patients with RE. In addition, this study supports the notion that Iba1-labeled microglial activation is increased in patients with active RE, compared with cases of CD and TSC.

Intravenous mesenchymal stem cell administration exhibits therapeutic effects against 6-hydroxydopamine-induced dopaminergic neurodegeneration and glial activation in rats

“…The Images were converted to black and white by Adobe Photoshop CS5.1 (Adobe Systems Inc.) and opened in ImageJ (NIH) for analysis. The area of microglial immunostaining was determined by ImageJ, which provided the absolute area of microglial immunolabeling within each image [23].…”

Microglia: dismantling and rebuilding circuits after acute neurological injury

“…Regardless of the etiology of RE, microglia activation is an essential hallmark of RE, a disease associated with seizures and chronic inflammation. Additionally, rod microglia were documented along neuronal apical dendrites of patients with RE [77], suggesting neuronal:microglial interactions. Furthermore, the magnitude of microglial reactivity in focal cortical dysplasia correlated with the duration of epilepsy and seizure frequency [78].…”

Intimal thickening of meningeal arteries after serial corticectomies for Rasmussen encephalitis

“…If indeed the presence of an exuberant inflammatory reaction in the CNS, regardless of the inciting event, contributes intimal hyperplasia, our findings raise the possibility that this may be a long-term complication in patients with other inflammatory diseases of the CNS, such as aseptic meningitis, other forms of encephalitis, vasculitis, and others [9][10][11][12][13][14][15][16][17][18][19]. Not surprisingly, biopsy or autopsy tissue from patients who have a remote history of these conditions (followed by recovery and some interval between second biopsy or autopsy) is rare at UCLA, making a simple direct observation to support this hypothesis difficult.…”