Mass spectral measurements of the apoHDL in horse (Equus caballus) cerebrospinal fluid.

As a continuation of our proteogenomic studies of equine apolipoproteins, we have obtained molecular masses for several of the apolipoproteins associated with the HDL in horse cerebrospinal fluid (CSF). Using electrospray-ionization mass spectrometry (ESI-MS), we report on values for apolipoproteins, A-I and A-II, as well as acylated apoA-I. In comparison with our previously published data on equine plasma apolipoproteins, there appears to be a higher percentage of acylated apoA-I in the CSF than in plasma. As was the case in plasma, apoA-II circulates as a homodimer. These studies also revealed a protein with a mass of 34,468Da that we are speculating is the value for horse apoE.

Identification of apolipoprotein A-II in cerebrospinal fluid of pediatric brain tumor patients by protein expression profiling.

BACKGROUND: Our aim was to detect differences in protein expression profiles of cerebrospinal fluid (CSF) from pediatric patients with and without brain tumors. METHODS: We used surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry and Q10 ProteinChip arrays to compare protein expression profiles of CSF from 32 pediatric brain tumor patients and 70 pediatric control patients. A protein with high discriminatory power was isolated and identified by subsequent anion-exchange and reversed-phase fractionation, gel electrophoresis, and mass spectrometry. The identity of the protein was confirmed by Western blotting and immunohistochemistry. RESULTS: Of the 247 detected protein peak clusters, 123 were differentially expressed between brain tumor and control patients with a false discovery rate of 1%. Double-loop classification analysis gave a mean prediction accuracy of 88% in discriminating brain tumor patients from control patients. From the 123 clusters, a highly overexpressed protein peak cluster in CSF from brain tumor patients was selected for further analysis and identified as apolipoprotein A-II. Apolipoprotein A-II expression in CSF was correlated with the CSF albumin concentration, suggesting that the overexpression of apolipoprotein A-II is related to a disrupted blood-brain barrier. CONCLUSIONS: SELDI-TOF mass spectrometry can be successfully used to find differentially expressed proteins in CSF of pediatric brain tumor and control patients. Apolipoprotein A-II is highly overexpressed in CSF of pediatric brain tumor patients, which most likely is related to a disrupted blood-brain barrier. Ongoing studies are aimed at finding subtype specific proteins in larger groups of pediatric brain tumor patients.

Levels of apolipoprotein A-II in cerebrospinal fluid in patients with neuroborreliosis are associated with lipophagocytosis.

Levels of most of the examined proteins in cerebrospinal fluid (CSF) of 107 patients with neuroborreliosis were associated with cytological findings, the status of hematoencephalic barrier as evaluated by Qalb (cerebrospinal fluid to serum quotient) and the intrathecal synthesis of immunoglobulins. Cytological findings consisted of normal cytology, or both oligocytosis and pleocytosis of monocytes or lymphocytes. The lipophagic elements were present in 20% of samples. Concentrations of apolipoproteins A-I and A-II in the CSF were correlated with the concentration of albumin without regard to the CSF cytology. The levels of apolipoprotein B were increased only in samples with lymphocytic pleocytosis and Qalb > 7.4. The presence of lipophages in the CSF was significantly associated with the CSF concentration of apolipoprotein A-II.