It was a joke my dude , I jokingly said he was being carried <| sep |> It is not like the BBB is infallible . Systemic LPS can also induce brain or CNS cytokine production and alter behavior without the necessity of systemic cytokine involvement , with some research indicating a direct LPS to CNS communication via brain endothelial cells . Indeed , systemic LPS can compromise the integrity of the normal bloodbrain barrier BBB and facilitate the passage of a host of potential agents environmental toxins , pathogens etc . as well as LPS itself . To make matters worse , the ability to remove potentially harmful neurotoxins e . g . amyloid betaderived neurotoxins from the brain through normally functioning efflux mechanisms at the BBB is also compromised by LPS . Among those with depression , the subsequent risk of dementia or mild cognitive impairment is up to 2 fold higher , and researchers continue to evaluate lowgrade inflammation as a primary driver of cognitive decline . Permeability of the bloodbrain barrier and the intestinal barrier is , at least in part , controlled by endocannabinoid modulation .