A cell-free extract from human adipose stem cells protects mice against epilepsy

Summary Purpose: Stem cell–based therapies are being considered for various neurologic diseases, such as epilepsy. Recent studies have suggested that some effects of transplanted stem cells are due to bystander effects that modulate the host environment, rather than direct effects of cell replacement. The extract from human adipose stem cells (ASCs) that secrete multiple growth factors including cytokines and chemokines may be a potential source of bystander effects for the treatment of epilepsy, in which inflammation is thought to play an important role. Here, we investigated the effects of a cytosolic extract of human ASCs (ASCs-E) in a mouse model of epilepsy. Methods: Human ASCs-E, boiled ASCs-E, or fibroblast-extract (fibroblast-E) was intraperitoneally administrated to C57BL/6 mice 15 min before pilocarpine-induced status epilepticus (SE) or during chronic epileptic stage. Blood–brain barrier (BBB) leakage was evaluated by measuring Evans blue dye extravasation. Spontaneous recurrent seizure (SRS) was investigated by long-term video–electroencephalography (EEG) monitoring. The mice performed elevated plus maze, open-field, light/dark transition, and novel object recognition tasks. Key Findings: Acute application of human ASCs-E before SE led to earlier attenuation of seizure spike activities after treatment with diazepam, reduction of BBB leakage, and inhibition of the development of epilepsy. Human ASCs-E treatment (for 7 days) during the chronic epileptic stage suppressed SRS and reduced abnormal epileptic behavioral phenotypes. However, neither boiled ASCs-E nor fibroblast-E had any effects in the experimental epilepsy model. Significance: Our results demonstrate that human ASCs-E prevents or inhibits epileptogenesis and SRS in mice. They also suggest a stem cell–based, noninvasive therapy for the treatment of epilepsy.