Hearing loss and its association with the proteome of perilymph, cerebrospinal fluid, and tumor tissue in patients with vestibular schwannoma.

This study examined the association between hearing loss in sporadic vestibular schwannoma patients and the proteome of perilymph (PL), cerebrospinal fluid (CSF), and vestibular schwannoma. Intraoperative sampling of PL and of CSF, and biopsy of vestibular schwannoma tissue, was performed in 32, 32, and 20 patients with vestibular schwannoma, respectively. Perilymph and CSF in three patients with meningioma and normal hearing were also sampled. The proteomes were identified by liquid chromatography coupled to high-resolution tandem mass spectrometry. Preoperative hearing function of the patients was evaluated with pure tone audiometry, with mean values at frequencies of 500, 1000, 2000, and 4000 Hz (PTA4) in the tumor-affected ear used to delineate three hearing groups. Analysis of the PL samples revealed significant upregulation of complement factor H-related protein 2 (CFHR2) in patients with severe to profound hearing loss after false discovery rate correction. Pathway analysis of biofunctions revealed higher activation scores in the severe/profound hearing loss group of leukocyte migration, viral infection, and migration of cells in PL. Upregulation of CFHR2 and activation of these pathways indicate chronic inflammation in the cochlea of vestibular schwannoma patients with severe to profound hearing loss compared with patients with normal hearing or mild hearing loss.

Protein profiling of cerebrospinal fluid from patients undergoing vestibular schwannoma surgery and clinical significance.

Vestibular schwannoma (VS) is a common disease in the region of the cerebellopontine angle in the posterior cranial fossa. Large VS and its surgical management usually lead to severe cranial nerve dysfunction and affect the patient's quality of life. We aimed to find some possible progression markers of VS. Here, we sought to characterize the cerebrospinal fluid (CSF) proteome of patients with different VS grades and recurrence to identify biomarkers predictive of VS growth or recurrence. CSF was collected intraoperatively prior to removal of untreated VS, including grade I-V and recurrence. Isobaric tags for relative and absolute quantitation-based proteomic analysis of CSF from 43 VS patients and 3 control patients was used to identify candidate proteins. Ninety-three overlapping proteins were found to display differential expression in grade I, II, III, IV, and V VS patients compared with the control group. Nine proteins were chosen for validation with enzyme-linked immunosorbent assay. VS was distinguished from control patients based on the expression patterns of six proteins (ATP-binding cassette subfamily A member 3 [ABCA3], secretogranin-1 [SCG1], Krueppel-like factor 11 [KLF11], voltage-dependent calcium channel subunit alpha-2/delta-1 [CA2D1], brain acid soluble protein 1 [BASP1], and peroxiredoxin-2 [PRDX2]. ABCA3 and KLF11 were positively correlated with the size of early-phase of VS, while BASP1 and PRDX2 showed a negative correlation. ABCA3, CA2D1, and KLF11 were upregulated, while BASP1 and PRDX2 were downregulated in the CSF from VS recurrence. But SCG1 was increased only at early-phase. These data suggest that increased ABCA3 and KLF11 and decreased BASP1 and PRDX2 in CSF are associated with VS growth at the early phase or recurrence.

Quantitative Proteomics of Vestibular Schwannoma Cerebrospinal Fluid: A Pilot Study.

This pilot study aimed to identify candidate proteins for future study that are differentially expressed in vestibular schwannoma (VS) cerebrospinal fluid (CSF) and to compare such proteins with those previously identified in perilymph and specimen secretions. CSF was collected intraoperatively prior to removal of untreated sporadic VS (3 translabyrinthine, 3 middle cranial fossa approaches) and compared with reference CSF samples. After proteolytic digestion and iTRAQ labeling, tandem mass spectrometry with ProteinPilot was used to identify candidate proteins. Of the 237 proteins detected, 13 were dysregulated in ≥3 of the 6 VS patients versus controls, and 13 were dysregulated (12 up, 1 down) in samples from patients with class D versus class B hearing. Four perilymph proteins of interest were dysregulated in ≥1 VS CSF samples. Thus, 26 candidate VS CSF biomarkers were identified that should be considered in future VS biomarker and tumor pathophysiology investigations.

Hydrocephalus associated with vestibular schwannomas: perioperative changes in cerebrospinal fluid.

BACKGROUND: Cerebrospinal fluid (CSF) protein levels are known to increase in patients with vestibular schwannomas (VS) with concomitant hydrocephalus, however the only information available on perioperative changes in CSF in these patients comes from case reports. Here, we investigated the relation between CSF protein and hydrocephalus in a large series of patients undergoing resection of VS. METHOD: We classified 376 patients undergoing resection for VS at our institute into two groups, namely VS and no hydrocephalus (control, n = 319) and VS with concomitant hydrocephalus (n = 57), and compared clinical parameters. Among the 57 patients diagnosed with hydrocephalus, hydrocephalus status was examined by lumbar puncture in 20 patients with communicative hydrocephalus, and pre- and postoperative scores in CSF properties were compared. RESULTS: Patients in the hydrocephalus group were significantly older than those in the control group (mean, 55.8 vs. 43.8 years), and had a longer disease duration (median, 76 vs. 12 months), larger tumors (median, 15.6 vs. 5.5 ml), and a higher protein concentration in CSF (median, 147.3 vs. 65.1 mg/dl). Perioperative CSF samples of hydrocephalus patients showed a significantly decrease in cerebrospinal pressure after tumor removal (median, -75mmH2O), followed by a decrease in CSF protein (median, -74.5 mg/dl). No patients required the placement of a shunt. CONCLUSIONS: Extended disease duration and elevated CSF protein secondary to the presence of a tumor contribute to the occurrence of hydrocephalus. Primary maximal tumor removal for VS with coexisting hydrocephalus avoids an unnecessary shunt.

Large and giant vestibular schwannomas: does cisterna magna hyperproteinorrhachia influence visual status?

BACKGROUND: Hyperproteinorrhachia associated with vestibular schwannomas (VSs) may influence visual status independent of the effect caused by raised intracranial pressure. The role of cisterna magna CSF protein levels (CMCP) in determining visual outcome in patients with large to giant vestibular schwannomas (VSs) was prospectively investigated. METHODS: The mean CMCP levels in VSs and control group; and, levels in VSs with or without visual deterioration were compared. Spearman's rank correlation coefficient tested for relationships between CMCP level with symptom duration and tumour volume (Kawamoto's method). Vision was regarded as normal when visual acuity was >6/18; and, deteriorated when it was between 6/18 and PL negative in the worse eye. Papilloedema (n = 26)/secondary optic atrophy (n = 6) and hydrocephalus (based on Evan's ratio, mild to moderate: n = 22; none: n = 18) were also recorded. The analysis of factors predicting diminished vision was done using logistic regression analysis (p < 0.05 significant). FINDINGS: There was a significant difference (p < 0.001) in mean CMCP levels between VS (456.3 SD 213.6 mg/dl) and control groups (96.3 SD 74.3 mg/dl). The mean CMCP levels in the VS group were also markedly higher than the ventricular mean protein levels. The CMCP levels in patients with visual diminution (<6/18 to PL negative; n = 23) was 561.4 SD 186.9 mg/dl and those without visual loss (n = 17) was 314.2 SD 160.8 mg/dl (p < 0.001). Their grade of visual diminution had a positive correlation with mean CMCP levels (p < 0.001). There was a negative correlation between total duration of symptoms and CMCP levels (p < 0.015). Logistic regression analysis using five independent factors (symptom duration, papilloedema/secondary optic atrophy, tumour volume, hydrocephalus and mean CMCP level) revealed that only CMCP level had a significant association with visual diminution. CONCLUSION: Elevated cisternal CSF proteins may play an important role in determining visual outcome in large to giant VSs. Ventricular CSF analysis is often unable confirm the presence of VS-associated cisternal hyperproteinorrhachia. High CMCP levels may influence decision-making while instituting a permanent CSF diversion for postoperative hydrocephalus or recalcitrant pseudomeningocoele.

Less than 1% cerebrospinal fluid leakage in 1,803 translabyrinthine vestibular schwannoma surgery cases.

OBJECTIVE: To determine the incidence rate of cerebrospinal fluid (CSF) leak after translabyrinthine vestibular schwannoma surgery since the alteration of the surgical procedure. To compare with previous series and other series in literature. STUDY DESIGN: Database analysis. SETTING: Tertiary referral neurotologic private practice. PATIENTS: A series of 1,803 patients who underwent translabyrinthine vestibular schwannoma surgery between 1993 and 2009. The result of this group was compared with corresponding series. INTERVENTION: Translabyrinthine and extended translabyrinthine vestibular schwannoma surgery. Literature review and comparison. MAIN OUTCOME MEASURES: Rates of CSF leak in this series and historical perspective of the outcome. RESULTS: Fifteen patients (0.8%) of 1,803 cases had CSF leaks. The method used since 1993 has shown a significant improvement compared with major case series of the last 10 years. CONCLUSION: The methods used in translabyrinthine vestibular schwannoma surgery in our center can reduce CSF leakage to an absolute minimum. Compared with all large series, this could be a new era of translabyrinthine vestibular schwannoma surgery.

Etiopathological factors related to hydrocephalus associated with vestibular schwannoma.

OBJECTIVE: We retrospectively analyzed various clinical factors to determine whether or not these factors are etiopathologically related to the development of hydrocephalus in patients with vestibular schwannomas. METHODS: There were 68 patients (29 men, 39 women) in this study who underwent resection of a vestibular schwannoma. The age at the time of surgery ranged from 19 to 76 years (mean age, 51.4 yr). The maximum diameter of the tumor in the cerebellopontine cistern ranged from 0 (localized within the internal auditory canal) to 56 mm (mean, 32.0 +/- 12.9 mm). Cerebrospinal fluid (CSF) protein concentration in the cerebellomedullary cistern was measured intraoperatively in all patients. RESULTS: Sixteen (23.5%) of the 68 patients exhibited radiographic evidence of hydrocephalus. Univariate analysis of various factors revealed that both tumor size and CSF protein concentration were positively related to development of hydrocephalus (P < 0.05 and P < 0.01, respectively). However, in multiple logistic regression analysis, only the CSF protein concentration was predictive for development of hydrocephalus (P = 0.022). There was a trend toward increased CSF protein concentration in patients with a large tumor (> or = 40 mm) compared with those with a small tumor (< 40 mm) (P = 0.06). CONCLUSION: A high CSF protein concentration in fluid from the cerebellomedullary cistern is one of the most important factors contributing to hydrocephalus associated with vestibular schwannoma. It is important to judge whether or not any further treatment is required for hydrocephalus, in addition to tumor resection, especially in patients with communicating hydrocephalus.

Dissemination of fat in CSF: a common finding following translabyrinthine acoustic neuroma surgery*.

OBJECTIVES: Following translabyrinthine craniotomy the temporal bone defect is commonly obliterated using a free autologous fat graft. In this series the dura was put back in place but not closed primarily. As the fat graft remains in direct contact with the cerebro spinal fluid (CSF) there is potential for dispersal of fat within the CSF space. This paper aims to determine the frequency of such CSF fat dissemination and its clinical significance. DESIGN: A retrospective review of translabyrinthine acoustic neuroma removal with free fat autograft obliteration of the temporal bone defect between the years 1997 and 2000. SETTING: Tertiary referral oto-neurosurgical centre. Postoperative magnetic resonance (MR) imaging. PARTICIPANTS: All translabyrinthine patients who had postoperative MR imaging were included. Twenty-six cases were identified. Age range was 13-70 years. Fourteen were male patients. MAIN OUTCOME MEASURES: Evidence of CSF fat dissemination on MR and patients' clinical findings. RESULTS: Twenty-two of the 26 scans (85%) demonstrated evidence of fat dissemination into the subarachnoid CSF spaces in the form of microemboli. The cerebellopontine angle was the most common site involved. No evidence of ventricular dilation or any other abnormality was noted. There was no relationship between the presence or extent of fat microembolization and the patients' clinical course. CONCLUSIONS: This study suggests that free fat placed in temporal bone defects commonly migrate into the subarachnoid space and subsequently move around in these spaces. This is not associated with any complications such as hydrocephalus, meningitis or prolonged postoperative headache.

[The permeability of the hemato-encephalic barrier in neurological cancer patients in the postoperative period]. / Pronitsaemost' gematoéntsefalicheskogo bar'era u neiroonkologicheskikh bol'nykh v posleoperatsionnom periode.

The permeability of the blood-brain barrier was studied in 48 patients by examining the protein indices of cerebrospinal fluid. The types of changes in the indices were identified, which reflected the level of the permeability and correlate with good and poor postoperative outcomes. Possible ways of correcting hypertransudation across the barrier were defined.

Infectious retrovirus is inactivated by serum but not by cerebrospinal fluid or fluid from tumor bed in patients with malignant glioma.

Intravenous gene transfer using recombinant retroviruses tends to suffer from a low infectious viral titer when conducted in vivo. This is, in part, caused by complement-mediated proteolytic inactivation of the retrovirus in human serum. However, if the retroviruses were directly injected into the brain, they might not be inactivated. Supernatant from amphotropic retrovirus-producing cells harboring the BAG vectors was incubated with sera or cerebrospinal fluid (CSF) of patients with gliomas or unrelated disorders. The retroviruses were severely inactivated in sera. However, no such inactivation was noted in CSF or fluid from the tumor bed of glioma patients. These data suggest that gene transfer using recombinant retroviruses could be done into the cavity after removal of the tumor in glioma patients.

Accumulation of nerve growth factor in cerebrospinal fluid and biological activity following neurosurgery.

Perioperative nerve growth factor (NGF) levels in cerebrospinal fluid (CSF) of patients with acoustic neurinoma (14 cases), tentorial meningioma (1 case), or subarachnoid hemorrhage (1 case) were examined. Preoperative NGF levels in CSF were below the level of detection in all patients. However, NGF was found to accumulate transiently in CSF following neurosurgery. Pre- and postoperative CSF obtained from a patient with acoustic neurinoma enhanced the proliferation of astrocytes in neuronal cell cultures derived from embryonic rat cortex grown in serum-free defined medium, and increased choline acetyltransferase activity of cholinergic neurons derived from embryonic rat septal area and brainstem. The effect of postoperative CSF on septal and brainstem neurons was more potent than that of preoperative CSF. These results indicate that NGF and non-NGF-type neurotrophic activities accumulate in the CSF following neurosurgery. These neurotrophic activities are probably important in the regeneration of damaged neural networks in the central nervous system.

Long term monitoring of immunoreactive endothelin-1 and endothelin-3 in ventricular cerebrospinal fluid, plasma, and 24-h urine of patients with subarachnoid hemorrhage.

Endothelins (ETs), peptides that were originally isolated from endothelial cells, have extremely potent and long-lasting vasoconstricting effects on cerebral vessels in vitro and in vivo. Observations that astrocytes produce these peptides and that their ET production can be stimulated, e.g. by thrombin, and potentiated via a self-enhancing autoregulatory mechanism may have shed new light upon the pathogenesis of cerebrovasospasm (CVS). ETs are present at low levels in normal human cerebrospinal fluid (CSF). Few and contradictory reports exist on ET levels in subarachnoid hemorrhage (SAH)-associated CVS. We monitored ventricular CSF, plasma, and 24-h urine levels of immunoreactive endothelin-1 (ET-1) and endothelin-3 (ET-3) in seven patients with SAH, who did (five) or did not (two) develop CVS in the course of their disease, as well as in two patients with different conditions (acoustic neuroma/postoperative meningitis; hydro-/hematocephalus) over 7-19 days. A distinct peak of both ET-1 and ET-3 in CSF of patients with SAH coincided with clinically documented signs of CVS and was absent in CSF of patients with SAH but no CVS. CSF levels of ET-1 and ET-3 displayed a striking parallelism in all subjects. Plasma ET-1 levels were essentially in the normal range. ET-3 was not detectable in plasma under our assay conditions. The excretion profiles of ET-1 and ET-3 in 24-h urine revealed again a predominantly parallel behavior of the two peptides. Interestingly, patients with high ET levels in CSF showed simultaneous peaks in urinary ET excretion, expressed as nanograms per gram of creatinine. Our findings support an association of ETs with the pathogenic events following SAH. The well-documented effects of these peptides on cerebral vessels suggest they are mediators rather than markers of disease.

Identification of perilymph proteins by two-dimensional gel electrophoresis.

Perilymph has a total protein component that is quantitatively distinct from serum and cerebrospinal fluid (CSF). The goal of this research was to determine if perilymph contains any qualitatively unique protein constituents that will distinguish it from serum or CSF. To test this hypothesis, matched sets of perilymph, serum, and CSF were obtained from 18 guinea pigs and seven human subjects. The purity of each sample was assured by measurement of the protein concentration of each sample and comparison of this parameter to known normal values for perilymph, serum, and CSF. Each sample was then subjected to two-dimensional gel electrophoresis, separating proteins by isoelectric point in the horizontal dimension and by relative molecular weight in the vertical dimension. All gels were processed under precisely identical physical conditions by use of a diamine silver stain. A small number of perilymph proteins not found in plasma were identified in both the guinea pig and the human specimens. The finding of unique perilymph proteins may permit the development of a sensitive marker that will aid in the diagnosis of perilymph fistula.

[Elevation of intracranial pressure during hemodialysis--continuous measurement of cerebrospinal fluid pressure in a patient with acoustic neurinoma].

Intracranial pressure (ICP) was continuously monitored in a thirty-two-year-old female of acoustic neurinoma complicated with chronic renal failure. Severe headache with vomiting has begun to appear during hemodialysis for several months, prompting a diagnosis of an obstructive hydrocephalus. Continuous ventricular drainage was placed after admission and changes of ICP were monitored during hemodialysis. Dynamic changes of electrolytes, protein, sugar, urea nitrogen, and creatinine levels in the cerebrospinal fluid (CSF) as well as osmolarity were measured every one hour during the hemodialysis. An increment of ICP started to occur gradually after initiation of hemodialysis reaching the maximum value 23 minutes later. It was spontaneously decreased to the initial level 8 minutes later followed by fluctuations thereafter consisting of the changes of 20 to 30 mmHg. A remarkable rise in osmotic pressure in CSF has been observed corresponding to the rise of ICP which created a large difference from the blood osmotic pressure that consistently decreased following the onset of hemodialysis. Whereas, the absolute values of all measured factors including electrolytes and urea nitrogen in CSF have decreased consistently which did not seem to contribute intermittent increment of osmotic pressure of CSF. The cause of ICP increment in our case was considered mainly due to increase of water content in the brain tissue caused by the widening of osmotic gradient between the CSF and blood, although the substances responsible to the actual increase of CSF osmotic pressure remained unclear.

Cerebrospinal fluid and acoustic neurinoma specific proteins in perilymph.

White rabbits were immunized with pooled and concentrated cerebro-spinal fluid (CSF) and with tumour homogenate concentrate from specimens taken from five patients with acoustic neurinoma. The absorbed anti-CSF-antitumour antiserum was tested with the micro-immunodiffusion test against normal human serum (NHS), CSF, perilymph and CSF from tumour patients and tumour homogenate. NHS showed no precipitates in any of the tests. One protein band was observed in all the other four reactants. Tumour tissue and perilymph had two proteins in common. Diffusion from the CSF space into the perilymph can thus occur via both the cochlear aqueduct and the internal acoustic meatus.

Spinal proteins in patients with acoustic neuromas.

The values of total spinal protein in cerebrospinal fluid (CSF), used as normal material, from 98 persons are presented. These values showed that the previously used reference limits (0.20-0.40 g/l) for total protein in CSF were too low, and consequently the new reference values 0.20-0.85 g/l are used. 77 patients with surgically verified acoustic neuromas had total protein determined in CSF prior to operation, and 63% of patients with tumours less than 25 mm in diameter had normal total protein values, while only 3% of patients with tumours larger than 25 mm had normal values. Since the large tumours can be easily diagnosed by the non-invasive computer tomography, it is concluded that CSF total protein determination is only of limited value in the search for acoustic neuromas. A more quantitated examination of CSF proteins (albumin, alpha 2-macroglobulin, IgA, IgG and IgM) showed significantly increased values among the tumour patients, but the findings were not of any significant clinical value in the diagnosis of tumours.

CSF total protein: normal values. A re-appraisal and discussion of its value in diagnosis of acoustic neuromas.

A reference material of total cerebrospinal fluid protein (CSF protein) from 53 men and 45 women is presented. Lowry's Folin-phenol method for determining CSF protein has been used unchanged in this laboratory since 1964, with normal values ranging from 0.2 to 0.4 g/l. In this new reference material higher values were found with the 0.05--0.95 fractile interval for normal CSF protein determined to 0.29--0.88 g/l. This implies that the value of determining CSF protein in diagnosis of acoustic neuromas is most questionable. Among the medium sized tumours there were statistically significant increased values, but no clinical significance. The large tumours showed both statistically as well as clinically significant increased protein, but these tumours can be easily diagnosed by other means. A more detailed determination of CSF protein is discussed.