A study examining astroglia and neurotrophic markers in the plasma of 20 PTSD veterans and 20 age-matched healthy control veterans reported low levels of neurotrophic factors (BDNF and NGF-β) as well as increased levels of glial fibrillary acidic protein (GFAP), TNF-α and IL-6 in PTSD veterans. This evidence concerns the gene BDNF and post-traumatic stress disorder.