Proteomic analysis of the cerebrospinal fluid of patients with restless legs syndrome/Willis-Ekbom disease.

BACKGROUND: Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a sensorimotor disorder that causes patients to experience overwhelming and distressing sensations in the legs compelling the patient to move their legs to provide relief. The purpose of this study was to determine if biomarkers in the cerebrospinal fluid can distinguish RLS/WED patients from neurological controls. METHODS: We obtained CSF samples by lumbar puncture from 5 early-onset RLS/WED patients and 5 controls. We performed 2-dimensional difference in-gel electrophoresis (2D-DIGE). Proteins that were significantly altered were identified by Student's t-test. Protein spots that were differentially expressed (p ≤ 0.05, Av. Ratio ≥ 2.0) between RLS/WED and control CSF samples were identified using MALDI-TOF-MS. Statistical analyses of the validation immunoblot assays were performed using Student's t-test. RESULTS: In this discovery study we identified 6 candidate CSF protein markers for early-onset RLS/WED. Four proteins (Cystatin C, Lipocalin-type Prostaglandin D2 Synthase, Vitamin D binding Protein, and ß-Hemoglobin) were increased and 2 proteins (Apolipoprotein A1 and α-1-acid Glycoprotein) were decreased in RLS/WED patients. CONCLUSIONS: Our results reveal a protein profile in the RLS/WED CSF that is consistent with clinical findings of disruptive sleep, cardiovascular dysfunction and painful symptoms. Moreover, protein profiles are consistent with neuropathological findings of activation of hypoxia inducible factor (HIF) pathways and alterations in dopaminergic systems. These data indicate the CSF of RLS/WED patients may provide information relevant to biological basis for RLS/WED, treatment strategies and potential new treatment targets.

CSF proteomic analysis reveals persistent iron deficiency-induced alterations in non-human primate infants.

Iron deficiency (ID) anemia during infancy results in long-term neurological consequences, yet the mediating mechanisms remain unclear. Infant monkeys often become naturally anemic during the first 6 months of life, presenting an opportunity to determine the effect of developmental iron deficiency. After weaning, animals were chosen randomly for supplementation with oral iron or, fed a standard commercial chow diet. The control group was never iron deficient. ID anemia was corrected by 12 months in both groups, as indicated by hematological parameters. CSF was collected for proteomic analysis at 12 months of age to assess the impact of developmental ID on the brain. The CSF proteome for both formerly iron deficient groups was similar and revealed 12 proteins with expression levels altered at least twofold. These proteins were identified by matrix assisted laser desorption ionization time-of-flight spectrometry and included prostaglandin D synthase, olfactory receptors and glial fibrillary acidic protein. Thus the proteomic analysis reveals a persistent effect of ID and provides insights into reports of disturbed sleep, hypomyelination and other behavioral alterations associated with ID. Furthermore, alterations in the CSF proteome despite normal hematologic parameters indicate that there is a hierarchical system that prioritizes repletion of red cell mass at the expense of the brain.