BACKGROUND: Species-specific differences in astrocytes and their Alzheimer disease-associated pathology may influence cellular responses to other insults. Herein, human glial chimeric mice were generated to evaluate how Alzheimer disease predisposing genetic background in human astrocytes contributes to behavioral outcome and brain pathology after cortical photothrombotic ischemia.METHODS: Neonatal (P0) immunodeficient mice of both sexes were transplanted with induced pluripotent stem cell-derived astrocyte progenitors from Alzheimer disease patients carrying PSEN1 exon 9 deletion (PSEN1 ΔE9), with isogenic controls, with cells from a healthy donor, or with mouse astrocytes or vehicle. After 14 months, a photothrombotic lesion was produced with Rose Bengal in the motor cortex. Behavior was assessed before ischemia and 1 and 4 weeks after the induction of stroke, followed by tissue perfusion for histology. RESULTS:Open field, cylinder, and grid-walking tests showed a persistent locomotor and sensorimotor impairment after ischemia and female mice had larger infarct sizes; yet, these were not affected by astrocytes with PSEN1 ΔE9 background. Staining for human nuclear antigen confirmed that human cells successfully engrafted throughout the mouse brain. However, only a small number of human cells were positive for astrocytic marker GFAP (glial fibrillary acidic protein), mostly located in the corpus callosum and retaining complex human-specific morphology with longer processes compared with host counterparts. While host astrocytes formed the glial scar, human astrocytes were scattered in small numbers close to the lesion boundary. Aβ (beta-amyloid) deposits were not present in PSEN1 ΔE9 astrocyte-transplanted mice. CONCLUSIONS:Transplanted human cells survived and distributed widely in the host brain but had no impact on severity of ischemic damage after cortical photothrombosis in chimeric mice. Only a small number of transplanted human astrocytes acquired GFAP-positive glial phenotype or migrated toward the ischemic lesion forming glial scar. PSEN1 ΔE9 astrocytes did not impair behavioral recovery after experimental stroke.

Introduction There are no published data on prospective clinical studies on drug treatment options for sleep‐related epileptiform spiking in Alzheimer's disease (AD). Methods Using video‐EEG with hippocampal electrodes in 17 APP/PS1 transgenic male mice we assessed the effects of donepezil and memantine, anti‐seizure drugs levetiracetam and lamotrigine, gamma‐secretase inhibitor semagacestat, anti‐inflammatory minocycline and adenosine receptor antagonist istradephylline on density of cortical and hippocampal spikes during sleep. Results Levetiracetam decreased the density of hippocampal giant spikes and cortical spikes. Lamotrigine reduced cortical single spikes and spike‐wave discharges but dramatically increased hippocampal giant spikes. Memantine increased cortical single spikes and spike‐wave discharges dose‐dependently. Memantine and istradephylline decreased total sleep time while levetiracetam increased it. Lamotrigine decreased REM sleep duration. Other drugs had no significant effects. Discussion Levetiracetam appears promising for treating sleep‐related epileptiform spiking in AD while lamotrigine should be used with caution. Donepezil at low doses appeared neutral but the memantine effects warrant further studies.