Fig. 1

Study design. A Human adipocyte derived mesenchymal stem cells (MSCs) were cultured and extracellular vesicles were isolated from the culture media. B After 2 weeks of starting the hyperammonemic diet, HA and control rats were intravenously injected in the tail vein either with 50 µg of protein of isolated vesicles from MSCs or PBS as vehicle. A second injection was performed one week later. Behavioral tests (Y-maze, novel object location, novel object recognition and 8-radial maze) were performed 10–20 days after first injection to assess cognitive function. Rats were killed during week 6 of hyperammonemia to extract the brain for neuroinflammation analysis. C We injected fluorescently labeled EVs into different rats with 4 weeks of HA (n = 2). Rats were killed after 3 days and hippocampi were extracted to assess whether fluorescent EVs reach this area. D Ex vivo experiments were performed to investigate the molecular pathways involved: control and HA rats were killed and the hippocampi were dissected and sliced. Hippocampal slices from HA rats were incubated with EVs derived from MSCs during 30 min. Control and HA slices without EVs incubation were included as reference. Additional pre-treatments of the MSC-EVs and controls were included (see “Materials and methods” section). After the incubation, slices were processed for neurotransmission and neuroinflammation analysis