Validating Blood Biomarkers of Brain Immune and Metabolic Dysfunction in Gulf War Illness

Nearly 30 years later, veterans with Gulf War Illness (GWI) continue to suffer from this persistent and debilitating illness, which remains difficult to diagnose due to the heterogeneity of clinical presentation and the complexity of biological responses to hazardous chemicals to which GW veterans were exposed during the 1990-1991 Gulf War (GW). Brain imaging studies of veterans with GWI and pre-clinical animal studies of rodents with GWI show that impaired bioenergetics and inflammation can be attributed to the atrophy of the axonal white matter tracts that link the cortical gray matter regions, and the alterations of lipid/metabolite levels. The investigators recent work shows that disturbed lipid profiles in the brain and blood after GW pesticide exposure in rodents accompany neurobehavioral and bioenergetics deficits and inflammation. The mechanisms of neurotoxicity after pesticide exposure include increases in the inactivation of lipid metabolizing enzymes. This may consequently result in accumulation of lipids in the body compartments that limit their availability for use as energy substrates, contributing to bioenergetic impairments and inflammation. These metabolic changes have also been linked to individuals who possess the apolipoprotein E (APOE) ε4 allele, a risk factor of aging related cognitive decline and neurodegenerative conditions, such as Alzheimer's disease (AD). Several studies have shown a correlation between lipid transport deficits and presence of the ε4 allele. The identification of specific lipids/metabolites and the APOE ε4 allele as important biomarkers of GWI would serve to objectively assess the brain pathology of GWI and identify subgroups of GWI based on symptom patterns and GW exposures.