CD68 and Alzheimer disease: The fecal bEV effects on microglia was further investigated by IBA1 and CD68 co-immunostaining, showing that higher CD68 immunoreactivity was detected in GF housed AppNL-G-F AD mice administered with SPF housed WT or AppNL-G-F bEVs- compared to the control treated GF housed AppNL-G-F AD mice (Figure 7(e,f)).