PON1 and Alzheimer disease: As plasma HDL-bound PON1 and PON3 participate in cholesterol efflux from macrophages to HDL, the suggested presence of PON1 and PON3 in brain astrocytes does not seem coincidental, and could suggest a role of PON1 and PON3 in astrocyte cholesterol efflux that is highly dysregulated by AD pathology.