Retinol-binding protein and retinol analysis in cerebrospinal fluid and serum of patients with and without idiopathic intracranial hypertension

Background: Several studies have implicated vitamin A-related compounds in the pathogenesis of idiopathic intracranial hypertension (IIH). The goal of this study was to compare cerebrospinal fluid (CSF) and serum concentrations of retinol and retinol-binding protein (RBP) in subjects with and without IIH. Methods: CSF and serum samples were collected from 87 subjects. The study population was composed of subjects with IIH (IIH group, n = 28), subjects with non-IIH neurologic conditions (neurology controls, n = 42), and subjects undergoing preoperative lumbar puncture but with no known neurologic conditions (anesthesia controls, n = 17). RBP levels (nM) were determined using radial immunodiffusion, and retinol levels (nM) were determined using high-performance liquid chromatography. Results: The retinol/RBP ratio was greater in CSF than in serum, especially in subjects with IIH. Conclusions: The finding of increased levels of unbound retinol in the CSF of subjects with IIH provides further evidence that vitamin A may be involved in the pathogenesis of 11H. Comparative statistical analyses revealed multivariate relationships that demonstrate the need to further investigate correlations between vitamin A and RBP levels in CSF and serum.