RESUMO
BACKGROUND: Apolipoprotein E (apoE) is closely involved in the pathogenesis of apoE-related diseases, such as Alzheimer's disease and cardiovascular disease. The redox modulation of cysteine-thiols in a protein is involved in various pathophysiological regulations; however, that of apoE has not been studied in detail. Herein, we devised an analytical method to determine the redox status of serum apoE and assessed its relation to serum cholesterol levels and apoE phenotype. METHODS: The present method was based on a band shift assay, using a photocleavable maleimide-conjugated polyethylene glycol. RESULTS: The basic characteristics of the present method were found to be satisfactory to determine the redox status of serum apoE quantitatively. Serum apoE was separated into its reduced-form (r-), non-reduced-form (nr-), apoE-AII complex, and homodimer using this method. R-apoE could be detected as a 40-kDa band, whereas nr-apoE remained as monomeric apoE. R-apoE displayed a preference for VLDL; however, the levels showed the correlation with HDL-cholesterol levels (p<0.005). Redox status of serum apoE was significantly different among apoE phenotypes. The quantitative ratios of nr-apoE to total apoE in serum from subjects with apoE4/E3 were higher than in serum from subjects with apoE3/E3 (p<0.0001) and apoE3/E2 (p<0.001). CONCLUSION: The redox status of serum apoE might be related to the synthesis of HDL. The information concerning the redox status of serum apoE provided by the present method may be a potent indicator to evaluate various apoE-related diseases.
Assuntos
Apolipoproteínas E/sangue , HDL-Colesterol/sangue , Apolipoproteína A-II/sangue , Apolipoproteína A-II/química , Apolipoproteína A-II/isolamento & purificação , Apolipoproteína E2/sangue , Apolipoproteína E2/química , Apolipoproteína E2/isolamento & purificação , Apolipoproteína E3/sangue , Apolipoproteína E3/química , Apolipoproteína E3/isolamento & purificação , Apolipoproteína E4/sangue , Apolipoproteína E4/química , Apolipoproteína E4/isolamento & purificação , Apolipoproteínas E/química , Apolipoproteínas E/isolamento & purificação , HDL-Colesterol/química , Cisteína/química , Diamida/química , Dimerização , Ditiotreitol/química , Ensaio de Desvio de Mobilidade Eletroforética , Células HEK293 , Humanos , Indicadores e Reagentes/química , Peso Molecular , Oxirredução , Processos Fotoquímicos , Polietilenoglicóis/química , Solubilidade , Reagentes de Sulfidrila/química , Raios UltravioletaRESUMO
A 64-year-old woman with diffuse large B-cell Lymphoma (DLBCL) complained of double vision and pain sensation in her limbs after eight cycles of chemotherapy. F-fluorodexyglucose-positron emission tomography (FDG-PET) 7 days after the onset of double vision showed no abnormal accumulation and confirmed remission of DLBCL according to the international criteria. However, she developed limb weakness and severe paresthesia. The second FDG-PET 41 days after onset showed increased uptake at the both the brachial and lumbar plexuses, suggesting neurolymphomatosis. Although FDG-PET appears to be a highly sensitive diagnostic method for neurolymphomatosis, it is sometimes difficult to detect neurolymphomatosis in early diagnose, such as with this case. Therefore, multiple examinations are necessary to determine neurolymphomatosis.