Cerebrospinal fluid and plasma lipopolysaccharide (LPS) levels in HIV-1 infection and associations with inflammation, blood-brain barrier permeability and neuronal injury
HIV infection is associated with increased systemic microbial translocation, neuro-inflammation and occasionally neuronal injury. Whether systemic LPS penetrates into the brain and contributes to neuro-inflammation remain unknown in HIV. Here, we measured plasma and cerebrospinal fluid (CSF) LPS levels along with biomarkers of neuro-inflammation (white blood cell counts and 40 soluble markers) and neurofilament light chain (NfL). Notably, CSF LPS was undetectable in all samples, including three HIV-infected individuals with dementia. Increased plasma LPS, neuro-inflammation, and blood-brain barrier (BBB) dysfunction were found in untreated HIV-infected individuals, but not in healthy or treated HIV-infected individuals. Plasma LPS levels were directly correlated with various markers of inflammation in both plasma and CSF, as well as with degree of BBB permeability but not with CSF NfL in HIV-infected subjects. These results suggest that the magnitude of microbial translocation associates with neuro-inflammation and BBB permeability in HIV without direct penetration into the central nervous system (CNS)
