Neurochemical markers of brain damage in cerebrospinal fluid during induction treatment of acute lymphoblastic leukemia in children

BACKGROUND

Central nervous system (CNS) irradiation has been replaced by systemic high-dose methotrexate (MTX) and intrathecal MTX in acute lymphoblastic leukemia treatment due to the risk of late effects. However, treatment without CNS irradiation might also cause brain damage.

PROCEDURE

Cerebrospinal fluid (CSF) was analyzed in 121 patients in an attempt to detect CNS injury. Seventy-three samples were analyzed for neuron-specific enolase (NSE), 108 for glial fibrillary acidic protein (GFAp), 110 for neurofilament protein light chain (NFp), and 70 for ascorbyl radical (AsR). Samples were taken at day 0, 8, 15, and 29 during induction treatment, including intrathecal MTX. Levels at days 8, 15, and 29 were compared with the levels before treatment.

RESULTS

NSE levels were 9.0 (+/-3.5) microg/L (mean (+/-SD)) at day 0, 15.0 (+/-5.3) at day 8 (P < 0.001), 13.6 (+/-4.7) at day 15 (P < 0.001) and 11.1 (+/-4.3) at day 29 (P < 0.001). GFAp were 177 (+/-98) ng/L at day 0, 206 (+/-101) at day 8 (P < 0.001), 200 (+/-106) at day 15 (n.s.) and 228 (+/-137) at day 29 (P < 0.001). NFp were below the detection limit 125 ng/L at day 0 in all 110 CSF samples analyzed, and increased significantly above the detection limit in 6/77 samples at day 8, in 11/84 at day 15 and in 22/91 at day 29. The AsR content did not change significantly.

CONCLUSIONS

Levels of NSE, GFAp, and NFp increased in CSF, which can be interpreted as early signs of brain damage. AsR levels do not show any convincing signs of oxidative stress.

Mid-life adiposity factors relate to blood-brain barrier integrity in late life

OBJECTIVE

We explored the relationship between adiposity factors measured during mid-life and blood-brain barrier (BBB) integrity measured via the cerebrospinal fluid/serum (CSF/S) albumin ratio in late life. Adiposity factors included body mass index and blood levels of sex hormone binding globulin (SHBG) and leptin. Design. Retrospective analyses over 24 years within a longitudinal study.

SETTING

Population-based sample. Subjects. Eighty-one women.

MAIN OUTCOME MEASURES

CSF/S albumin ratio.

RESULTS

The CSF/S albumin ratio measured at age 70-84 years was higher amongst women who were overweight or obese (6.50 +/- 2.79 vs. 5.23 +/- 1.61, age-adjusted P = 0.012), and was inversely correlated with SHBG (age-adjusted r = -0.321, P < 0.005) at age 46-60 years. In stepwise regression models, SHBG predicted the CSF/S albumin ratio (beta = -0.017, R2 = 0.107, P = 0.007). The best model (R2 = 0.187) predicting CSF/S albumin ratio included SHBG, age group (age 46 years versus >46), overweight or obesity, and an age group by SHBG interaction.

CONCLUSIONS

Lower levels of SHBG in mid-life were related to worse BBB integrity in women after 24 years in late life, even considering other adiposity factors. SHBG may be important for understanding sex hormone-mediated mechanisms in brain health or as an independent marker of adipose tissue, the largest endocrine organ.

Serum levels of glial fibrillary acidic protein correlate to tumour volume of high-grade gliomas

OBJECTIVES

To investigate serum levels of glial fibrillary acidic protein (GFAP) and S-100B in patients with newly diagnosed high-grade gliomas.

MATERIALS AND METHODS

GFAP and S-100B were measured by enzyme-linked immunosorbent assay techniques in preoperative serum from 31 patients with high-grade gliomas. A database with clinical, radiological and histological variables was created for statistical analyses.

RESULTS

Mean serum levels of 239 ng/l (range 30-1210 ng/l) for GFAP and 58.3 ng/l (range 22-128 ng/l) for S-100B were found. Of the 31 patients, 16 had elevated levels of GFAP while only two showed increased S-100B concentrations. Tumour size was the only variable significantly associated with serum levels of GFAP (P < 0.0001) with a linear correlation coefficient of 0.67.

CONCLUSIONS

Serum levels of GFAP demonstrated a linear correlation to tumour volume in patients with high-grade gliomas. GFAP seems to be a more reliable biomarker in patients with high-grade gliomas than the commercially available S-100B.

CSF biomarkers in the evaluation of idiopathic normal pressure hydrocephalus

BACKGROUND - To evaluate cerebrospinal fluid (CSF) markers for neuronal degeneration and demyelination in idiopathic normal pressure hydrocephalus (INPH), subcortical arteriosclerotic encephalopathy (SAE), and neurologically healthy subjects. METHODS - Lumbar CSF concentrations of sulfatide, neurofilament protein light (NFL), total-tau (T-tau), hyperphosphorylated tau (P-tau), and beta-amyloid(1-42) (Abeta42) were analyzed in 62 INPH patients, 26 SAE patients, and 23 neurologically healthy controls. In INPH patients, samples before and after shunt surgery were analysed. RESULTS - The CSF concentration of NFL was elevated in INPH and SAE compared with the controls, and levels of T-tau, P-tau, and Abeta42 were lower in INPH compared with SAE and controls. No difference was seen for sulfatide. All markers except Abeta42 were significantly elevated after shunt surgery. CONCLUSIONS - The most striking finding was the power of the combined pattern of NFL, P-tau, and Abeta42 in distinguishing between the clinical diagnoses of INPH, SAE, and neurologically healthy elderly.

The relationship between cerebrospinal fluid biomarkers and depression in elderly women

OBJECTIVE

Cerebrospinal fluid (CSF) biomarkers including the 42 amino-acid form of beta-amyloid (Abeta42), total tau protein (T-tau), and the CSF/serum albumin ratio are markers of brain pathology and metabolism. Abeta42 and T-tau are sometimes used to discriminate geriatric depression from mild forms of Alzheimer disease (AD) in clinical studies. However, studies focusing on the relationship between these CSF biomarkers and geriatric depression are lacking.

METHODS

This was a cross-sectional study with a population-based sample of 84 nondemented elderly women in Sweden. Measurements included neuropsychiatric, physical, and lumbar puncture examinations, with Diagnostic and Statistical Manual of Mental Disorders, Third Revision-based depression diagnoses and measurement of CSF levels of Abeta42, T-tau, albumin, and serum albumin.

RESULTS

Fourteen women (mean age: 72.6 years) had any depression (11 with major depressive disorder [MDD]). Compared to women without depression, women with MDD had higher levels of Abeta42 and the CSF/serum albumin ratio. The CSF/serum albumin ratio was also higher in women with any depression. No differences in T-tau were observed; however, T-tau increased with age.

CONCLUSION

Higher levels of CSF Abeta42 were observed among elderly depressed women, in contrast to lower levels usually observed in AD, indicating potential neuropathological differences between the two disorders. Higher CSF/serum albumin ratios observed in depressed women point to potential vascular processes.

Cerebrospinal fluid neurofilament light levels in amyotrophic lateral sclerosis: impact ofSOD1genotype

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative syndrome with familial and sporadic forms. Most ALS-associated mutations are found in the superoxide dismutase 1 (SOD1) gene. We conducted a study including 60 sporadic and 19 familial ALS patients, 206 reference patients with other neurological disorders and 40 age- and sex-matched healthy controls to test the hypothesis that cerebrospinal fluid (CSF) levels of neurofilament light (NF-L) protein, a marker of axonal degeneration, might provide diagnostic and prognostic information on the disease. All ALS patients were screened for SOD1 mutations. Ten of the familial and five of the sporadic cases carried SOD1 mutations. NF-L concentration [median (range)] was strongly elevated in ALS [2110 (255-10 800) ng/l] compared with reference patients and healthy controls [277 (<125-15 506) and 175 (<125-710) ng/l, respectively, P < 0.001] and correlated inversely with disease duration (Spearman R = -0.518, P = 0.001). NF-L levels were lower in SOD1 mutation-associated ALS compared with SOD1 wild-type (wt) ALS (P = 0.03). In conclusion, CSF NF-L levels may provide both diagnostic and prognostic information, particularly in SOD1 wt ALS.

Picropodophyllin induces downregulation of the insulin-like growth factor 1 receptor: potential mechanistic involvement of Mdm2 and β-arrestin1

The insulin-like growth factor 1 receptor (IGF-1R) is crucial for growth and survival of malignant cells. Experience in targeting IGF-1R in cancer models has shown that strategies promoting downregulation of the receptor are much more efficient in inducing apoptosis than those inhibiting the IGF-1R activity. Recently, we found that the cyclolignan picropodophyllin (PPP) inhibits phosphorylation of IGF-1R and activation of downstream signaling without interfering with the highly homologous insulin receptor (IR). Furthermore, PPP treatment caused strong regression of tumor grafts and prolonged survival of animals with systemic tumor disease. Here we demonstrate that PPP also downregulates the IGF-1R, whereas the IR and several other receptors were not affected. PPP-induced IGF-1R downregulation required expression of the MDM2 E3 ligase, which recently was found to ubiquitinate and cause degradation of the IGF-1R. In addition knockdown of beta-arrestin1, the adaptor molecule known to bridges MDM2 and IGF-1R, prevented downregulation of the receptor and significantly decreased PPP-induced cell death. All together these data suggest that PPP downregulates IGF-1R by interfering with the action of beta-arrestin1/MDM2 as well as the achieved receptor downregulation contributes to the apoptotic effect of PPP.

Elevated Cerebrospinal Fluid Neurofilament Light Protein Concentrations Predict the Development of AIDS Dementia Complex

The light subunit of neurofilament protein (NFL) is a sensitive indicator of central nervous system axonal injury. We retrospectively identified 9 subjects participating in a longitudinal cohort study who developed acquired immunodeficiency syndrome dementia complex (ADC) and who had had a lumbar puncture performed within 2 years before presentation. Elevated cerebrospinal fluid (CSF) NFL concentrations were found in 7 (78%) of the 9 case patients who later developed ADC, compared with 9 (33%) of 27 CD4 cell count-matched HIV-1-infected control subjects. By contrast, no differences were found in CSF HIV-1 RNA or neopterin concentrations between the 2 groups. CSF NFL may prove to be a useful predictive marker for ADC.

No neurochemical evidence for brain injury caused by heading in soccer

BACKGROUND

The possible injurious effect to the brain of heading in soccer is a matter of discussion.

OBJECTIVE

To determine whether standardised headings in soccer are associated with increased levels of biochemical markers for neuronal injury in cerebrospinal fluid (CSF) and serum.

METHODS

23 male amateur soccer players took part in a heading training session involving heading a ball kicked from a distance of 30 m at least 10 m forward. Ten players performed 10 and 13 players performed 20 approved headings. The players underwent lumbar puncture and serum sampling 7-10 days after the headings. The study also included 10 healthy male non-athletic control subjects. CSF was analysed for neurofilament light protein, total tau, glial fibrillary acidic protein, S-100B and albumin concentrations. Serum was analysed for S-100B and albumin.

RESULTS

None of the biomarker levels were abnormal and there were no significant differences between any of the three groups, except for a slightly increased CSF S-100B concentration in controls compared with headers. Biomarker levels did not correlate with the number of headings performed.

CONCLUSION

Repeated low-severity head impacts due to heading in soccer are not associated with any neurochemical signs of injury to the brain.

Serum Glial Fibrillary Acidic Protein Is Related to Focal Brain Injury and Outcome After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Aneurysmal subarachnoid hemorrhage (aSAH) stands out from other subtypes of stroke because of the high early mortality and the risk of complications. Serum glial fibrillary acidic protein (s-GFAP) concentrations are increased after stroke. The aim of this study was to investigate whether s-GFAP could be used as a marker of brain damage and outcome after aSAH.

METHODS

Serum samples were obtained on a regular basis from 116 adults during a 2-week period after aSAH and analyzed using an enzyme-linked immunosorbent assay. The World Federation of Neurological Surgeons scale was used for neurological evaluation. Outcome was assessed after 1 year and categorized according to the Extended Glasgow Outcome Scale.

RESULTS

Increased s-GFAP levels were seen in 81 of the 116 patients. Maximum s-GFAP correlated with World Federation of Neurological Surgeons scale on arrival and on days 10 to 15 (r=0.37, P<0.001 and r=0.47, P<0.001, respectively). Furthermore, maximum s-GFAP levels were increased in the patient group with radiological signs of focal lesions acute or at 1 year, compared with the group without focal lesions (P<0.001 in both comparisons). Patients with secondary events (re-bleeding or ischemia) reached maximum levels later in the series and both maximum and final s-GFAP levels increased compared with the levels in patients without secondary events (P<0.001 in all 3 comparisons). Finally, maximum s-GFAP correlated with outcome (r=-0.48, P<0.001) and s-GFAP was an independent predictor of dichotomized outcome.

CONCLUSIONS

s-GFAP provides information about brain injury severity and outcome after aSAH, which can be useful as a complement to clinical data.

Cerebrospinal fluid beta-amyloid 1-42 concentration may predict cognitive decline in older women

BACKGROUND

Low levels of cerebrospinal fluid (CSF) beta-amyloid 1-42 (Abeta42) and high total tau (T-tau) are diagnostic for manifest Alzheimer's disease. It is not known, however, whether these biomarkers may be risk indicators for cognitive decline in otherwise healthy older people.

METHODS

The longitudinal relationship between CSF markers, Abeta42 and T-tau, measured in 1992, and change in Mini-Mental State Examination (deltaMMSE) score between 1992 and 2002 were investigated in 55 women (aged 70-84 years, mean (SD) MMSE score = 28.3 (1.5)), who were participants in the Prospective Population Study of Women in Gothenburg, Sweden. These women did not have dementia when they experienced lumbar puncture in 1992-3.

RESULTS

Over the 8-year follow-up period, deltaMMSE (range = +3 to -21 points) was correlated with Abeta42 (Spearman's r = 0.40, p = 0.002), such that lower levels of Abeta42 were related to greater decline. This was also observed after excluding 4 women who developed dementia between 1992 and 2002 (Spearman's r = 0.34, p = 0.019). A multivariate logistic regression model predicting a decline of > or = 5 points on the MMSE (observed in six women), or a risk of developing dementia over the 8-year follow-up period (observed in four women), including age, education, Abeta42 and T-tau as covariates, showed that Abeta42 was the sole predictor of significant cognitive decline or dementia (OR per 100 pg/ml Abeta42 = 2.24, 95% CI 1.19 to 4.22, p = 0.013).

CONCLUSIONS

Low levels of CSF Abeta42 may predict cognitive decline among older women without dementia.

CSF neurofilament protein (NFL) — a marker of active HIV-related neurodegeneration

BACKGROUND AND METHODS

The light subunit of the neurofilament protein (NFL), a major structural component of myelinated axons, is a sensitive indicator of axonal injury in the central nervous system (CNS) in a variety of neurodegenerative disorders. Cerebrospinal fluid (CSF) NFL concentrations were measured by ELISA (normal < 250 ng/l) in archived samples from 210 HIV-infected patients not taking antiretroviral treatment: 55 with AIDS dementia complex (ADC), 44 with various CNS opportunistic infections/tumours (CNS OIs), 95 without neurological symptoms or signs, and 16 with primary HIV infection (PHI). The effect of highly active antiretroviral treatment (HAART) was studied by repeated CSF sampling in four of the ADC patients initiating treatment.

RESULTS

CSF NFL concentrations were significantly higher in patients with ADC (median 2590 ng/l, IQR 780-7360) and CNS OIs (2315 ng/l, 985-7390 ng/l) than in neuroasymptomatic patients (<250 ng/l, <250-300) or PHI (<250 ng/l, <250-280), p < 0.001. Among patients with ADC, those with more severe disease (stage 2-4) had higher levels than those with milder disease (stage 0.5-1), p < 0.01. CSF NFL declined during HAART to the limit of detection in parallel with virological response and neurological improvement in ADC.CSF NFL concentrations were higher in neuroasymptomatic patients with lower CD4-cell strata than higher, p < 0.001. This increase was less marked than in the ADC patients and noted in 26/58 neuroasymptomatic patients with CD4 counts <200/microl compared to 1/37 with CD4-cells > or =200/microl.

CONCLUSIONS

The findings of this study support the value of CSF NFL as a useful marker of ongoing CNS damage in HIV infection. Markedly elevated CSF NFL concentrations in patients without CNS OIs are associated with ADC, follow the grade of severity, and decrease after initiation of effective antiretroviral treatment. Nearly all previously suggested CSF markers of ADC relate to immune activation or HIV viral load that do not directly indicate brain injury. By contrast NFL is a sensitive marker of such injury, and should prove useful in evaluating the presence and activity of ongoing CNS injury in HIV infection.

Multilevel somatosensory evoked potentials and cerebrospinal proteins: indicators of spinal cord injury in thoracoabdominal aortic aneurysm surgery

OBJECTIVE

Multilevel somatosensory evoked potentials (SSEP) and the release of biochemical markers in cerebrospinal fluid (CSF) were investigated to identify patients with spinal cord ischemia during thoracoabdominal aortic repair and/or a vulnerable spinal cord during the postoperative period.

METHODS

Thirty-nine consecutive patients undergoing elective aneurysm repair using distal aortic perfusion and cerebrospinal fluid drainage were studied. Continuous SSEP were monitored using nerve stimulation of the right and left posterior tibial nerves with signal recording at the level of both common peroneal nerves, the cervical cord and at the cortical level. CSF concentrations of the markers glial fibrillary acidic protein (GFAp), the light subunit of neurofilament triplet protein (NFL), and S100B were determined at different time points from before surgery until 3 days postoperatively.

RESULTS

SSEP indicated spinal cord ischemia in two patients leading to additional intercostal artery reattachments. In one of them the signal loss was permanent and the patient woke up with paraplegia. In the other the signal returned but the patient later developed delayed paraplegia. Three patients without SSEP indications of spinal cord ischemia during surgery later developed delayed paraplegia. The patients with spinal cord symptoms had significant increases, during the postoperative period of CSF biomarkers GFAp (571-fold), NFL (14-fold) and S100B (18-fold) compared to asymptomatic patients. GFAp increased before or in parallel to onset of symptoms in the patients with delayed paraplegia.

CONCLUSIONS

Peroperative multilevel SSEP has a high specificity in detecting spinal cord ischemia but does not identify all patients with a postoperative vulnerable spinal cord. Biochemical markers in CSF increase too late for intraoperative monitoring but GFAp is promising for identifying patients at risk for postoperative delayed paraplegia.

Elevated cerebrospinal fluid F2-isoprostane levels indicating oxidative stress in healthy siblings of multiple sclerosis patients

Lipid peroxidation has been implicated in the pathogenesis of multiple sclerosis (MS). Isoprostanes, isomers of prostaglandins, are produced by free radical-mediated peroxidation of fatty acids in vivo and can be quantified in biological fluids. This study examines the levels of cerebrospinal fluid (CSF) F2-isoprostanes (F2-iPs) in MS patients (n=46), their healthy siblings (n=46) and unrelated controls (n=50). The median CSF F2-iP concentration (range) was significantly higher in siblings of MS patients, as compared to healthy controls (40.0 [7.1-68.7] and 29.1 [6.4-60.3] pg/mL, respectively, p=0.031). MS patients demonstrated F2-iP levels intermediate between siblings and controls. F2-iP levels in MS patients and siblings correlated significantly (R=0.360, p=0.012). These results suggest that siblings of MS patients have an increased oxidative stress response to environmental and/or genetic factors that may be involved in MS pathogenesis.

Initial CSF total tau correlates with 1-year outcome in patients with traumatic brain injury

OBJECTIVE

We investigated if tau, microtubular binding protein, in serum and ventricular CSF (vCSF) in patients with severe traumatic brain injury (TBI) during the initial posttraumatic days correlated to 1-year outcome.

METHODS

Patients with severe TBI (n = 39, Glasgow Coma Scale score <or=8) were included. We measured serum and vCSF total tau on days 0 to 14, using ELISA. vCSF total tau correlated to 1-year Extended Glasgow Outcome Scale (GOSE), the NIH Stroke Scale (NIHSS) neurologic status, and the Bartel Daily Living Index. Patients (n = 20) with normal pressure hydrocephalus (NPH) served as reference.

RESULTS

Higher levels of tau were found in TBI patients vs patients with NPH. A correlation was found between initial vCSF total tau and GOSE levels (R = 0.42, p < 0.001) but not between vCSF total tau and NIHSS or Bartel scores at 1 year. A vCSF total tau level of >2,126 pg/mL on days 2 to 3 discriminated between dead and alive (sensitivity of 100% and a specificity of 81%). A vCSF total tau level of >702 pg/mL on days 2 to 3 discriminated between bad (GOSE 1 to 4) and good (GOSE 5 to 8) outcome (sensitivity of 83% and a specificity of 69%). Patients with GOSE 1 (dead) had higher vCSF total tau levels on days 2 to 3 (p < 0.001) vs both surviving patients (GOSE 2 to 8) and those with NPH. Total tau was not detected in serum throughout the study.

CONCLUSION

The increase in ventricular CSF (vCSF) total tau probably reflects axonal damage, known to be a central pathologic mechanism in traumatic brain injury (TBI). These results suggest that vCSF total tau may be an important early biochemical neuromarker for predicting long-term outcome in patients with a severe TBI.

Neurochemical aftermath of amateur boxing

BACKGROUND

Little solid information is available on the possible risks for neuronal injury in amateur boxing.

OBJECTIVE

To determine whether amateur boxing and severity of hits are associated with elevated levels of biochemical markers for neuronal injury in cerebrospinal fluid.

DESIGN

Longitudinal study.

SETTING

Referral center specializing in evaluation of neurodegenerative disorders.

PARTICIPANTS

Fourteen amateur boxers (11 men and 3 women) and 10 healthy male nonathletic control subjects.

INTERVENTIONS

The boxers underwent lumbar puncture 7 to 10 days and 3 months after a bout. The control subjects underwent LP once.

MAIN OUTCOME MEASURES

Neurofilament light protein, total tau, glial fibrillary acidic protein, phosphorylated tau, and beta-amyloid protein 1-40 (Abeta([1-40])) and 1-42 (Abeta([1-42])) concentrations in cerebrospinal fluid were measured.

RESULTS

Increased levels after a bout compared with after 3 months of rest from boxing were found for 2 markers for neuronal and axonal injury, neurofilament light protein (mean +/- SD, 845 +/- 1140 ng/L vs 208 +/- 108 ng/L; P = .008) and total tau (mean +/- SD, 449 +/- 176 ng/L vs 306 +/- 78 ng/L; P = .006), and for the astroglial injury marker glial fibrillary acidic protein (mean +/- SD, 541 +/- 199 ng/L vs 405 +/- 138 ng/L; P = .003). The increase was significantly higher among boxers who had received many hits (>15) or high-impact hits to the head compared with boxers who reported few hits. In the boxers, concentrations of neurofilament light protein and glial fibrillary acidic protein, but not total tau, were significantly elevated after a bout compared with the nonathletic control subjects. With the exception of neurofilament light protein, there were no significant differences between boxers after 3 months of rest from boxing and the nonathletic control subjects.

CONCLUSIONS

Amateur boxing is associated with acute neuronal and astroglial injury. If verified in longitudinal studies with extensive follow-up regarding the clinical outcome, analyses of cerebrospinal fluid may provide a scientific basis for medical counseling of athletes after boxing or head injury.

Normalisation of cerebrospinal fluid biomarkers parallels improvement of neurological symptoms following HAART in HIV dementia--case report

Background

Since the introduction of HAART the incidence of HIV dementia has declined and HAART seems to improve neurocognitive function in patients with HIV dementia. Currently, HIV dementia develops mainly in patients without effective treatment, though it has also been described in patients on HAART and milder HIV-associated neuropsychological impairment is still frequent among HIV-1 infected patients regardless of HAART. Elevated cerebrospinal fluid (CSF) levels of markers of neural injury and immune activation have been found in HIV dementia, but neither of those, nor CSF HIV-1 RNA levels have been proven useful as diagnostic or prognostic pseudomarkers in HIV dementia.

Case presentation

We report a case of HIV dementia (MSK stage 3) in a 57 year old antiretroviral naïve man who was introduced on zidovudine, lamivudine and ritonavir boosted indinavir, and followed with consecutive lumbar punctures before and after two and 15 months after initiation of HAART. Improvement of neurocognitive function was paralleled by normalisation of CSF neural markers (NFL, Tau and GFAP) levels and a decline in CSF and serum neopterin and CSF and plasma HIV-1 RNA levels.

Conclusion

The value of these CSF markers as prognostic pseudomarkers of the effect of HAART on neurocognitive impairment in HIV dementia ought to be evaluated in longitudinal studies.

Defining and evaluating HIV-related neurodegenerative disease and its treatment targets: a combinatorial approach to use of cerebrospinal fluid molecular biomarkers

There are a number of reasons that the accomplishments of clinical trials related to HIV-related neurodegenerative disease (HRND) and the AIDS dementia complex (ADC) have had such limited impact on clinical practice. These include: rapid evolution and progress in the treatment of systemic HIV infection that has quickly outpaced neurological efforts and has markedly reduced disease incidence; ethical constraints that (rightly) demand neurologically compromised patients receive the best available treatment before experimental therapeutics; complicated backgrounds and comorbidities of patients now most susceptible to HRND; and reluctance of general AIDS clinicians and drug companies to look beyond systemic or pivotal outcomes. However, the field has also been slow to adopt methods that better exploit advances in understanding of the pathogenesis of central nervous system (CNS) infection and brain injury, and that might circumvent some of these constraints. Using a simple model of pathogenesis, we propose an approach to characterizing patients, selecting treatment targets, and evaluating outcomes that emphasize a combination of cerebrospinal fluid (CSF) markers. This model begins by using three markers related to cardinal components of HRND: CNS HIV infection (measurement of CSF HIV RNA), intrathecal immunoactivation (CSF neopterin), and brain injury [CSF light chain neurofilament (NFL)]. Careful analysis of this and other marker combinations promises more rational trial design and more rapid progress in managing CNS HIV infection and HRND using both antiviral and adjuvant treatment approaches.

CSF –Neurofilament correlates with outcome after aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating event. Following the bleeding, a number of pathophysiological changes and clinical factors determine outcome. Not surprisingly, attempts to predict outcome based on a single factor have failed. The neurological status graded at admission to hospital and distributions of the blood on CT are the strongest predictors. There is evidence that cerebrospinal fluid (CSF) proteins may serve as markers of the extent of brain damage. The present study is focused on the light unit of neurofilament protein (NFL), previously not evaluated in aSAH. Lumbar puncture (LP), neurological grading according to World Federation of Neurological Surgeons (WFNS) and neurological examination according to the National Institute of Health Stroke Scale (NIHSS) were performed in 48 consecutive patients with aSAH 10-14 days after the hemorrhage. CSF-NFL concentrations were analyzed using an ELISA. Outcome was assessed after 1 year and categorised according to the extended Glasgow Outcome Scale (GOSE). A significant correlation between CSF-NFL and GOSE was detected at follow up after 1 year. CSF-NFL also correlated with WFNS and NIHSS on the day of the lumbar puncture. CSF-NFL is a biochemical marker of brain damage correlating to neurological status and long-term outcome after aneurysmal subarachnoid hemorrhage.

Exposure of Cultured Astroglial and Microglial Brain Cells to 900 MHz Microwave Radiation

The rapid rise in the use of mobile communications has raised concerns about health issues related to low-level microwave radiation. The head and brain are usually the most exposed targets in mobile phone users. In the brain, two types of glial cells, the astroglial and the microglial cells, are interesting in the context of biological effects from microwave exposure. These cells are widely distributed in the brain and are directly involved in the response to brain damage as well as in the development of brain cancer. The aim of the present study was to investigate whether 900 MHz radiation could affect these two different glial cell types in culture by studying markers for damage-related processes in the cells. Primary cultures enriched in astroglial cells were exposed to 900 MHz microwave radiation in a temperature-controlled exposure system at specific absorption rates (SARs) of 3 W/kg GSM modulated wave (mw) for 4, 8 and 24 h or 27 W/kg continuous wave (cw) for 24 h, and the release into the extracellular medium of the two pro-inflammatory cytokines interleukin 6 (Il6) and tumor necrosis factor-alpha (Tnfa) was analyzed. In addition, levels of the astroglial cell-specific reactive marker glial fibrillary acidic protein (Gfap), whose expression dynamics is different from that of cytokines, were measured in astroglial cultures and in astroglial cell-conditioned cell culture medium at SARs of 27 and 54 W/kg (cw) for 4 or 24 h. No significant differences could be detected for any of the parameters studied at any time and for any of the radiation characteristics. Total protein levels remained constant during the experiments. Microglial cell cultures were exposed to 900 MHz radiation at an SAR of 3 W/kg (mw) for 8 h, and I16, Tnfa, total protein and the microglial reactivity marker ED-1 (a macrophage activation antigen) were measured. No significant differences were found. The morphology of the cultured astroglial cells and microglia was studied and appeared to be unaffected by microwave irradiation. Thus this study does not provide evidence for any effect of the microwave radiation used on damage-related factors in glial cells in culture.

Low serum potassium in mid life associated with decreased cerebrospinal fluid Abeta42 in late life

Low serum potassium increases risk of hypertension and stroke, and cardiovascular factors increase the risk of Alzheimer disease (AD). We examined the association between serum potassium and the biologic marker cerebrospinal fluid amyloid-beta (Abeta42), which is decreased in Alzheimer disease patients. Psychiatric examinations, laboratory and other tests were conducted on a population-based sample of 1080 women aged 46 to 60 in 1968, with follow-ups in 1974, 1980, and 1992. In 1992, cerebrospinal fluid Abeta42 levels were obtained from 81 women. Increasing serum potassium in 1968 was associated with increasing cerebrospinal fluid Abeta42 (beta = 153.9, P = 0.041) in 1992 using age-adjusted linear regression. Compared with the lowest tertile of potassium, the middle (beta = 95.3, P = 0.138) and highest tertiles (beta = 193.5, P = 0.004) had incrementally increased cerebrospinal fluid Abeta42 levels. Associations remained after controlling for blood pressure and other factors, and were similar among the 17 women in 1974 with available serum potassium. Potassium in 1980 and 1992 was not associated with cerebrospinal fluid Abeta42. Findings suggest low serum potassium in mid life, but not late life, is associated with low cerebrospinal fluid Abeta42 levels in late life. It is possible potassium co-varies with another variable that is associated with cerebrospinal fluid Abeta42. Nonetheless, serum potassium is a modifiable risk factor and further examination of the potassium-dementia relationship is warranted.

Temporarily controlled HIV-1 replication after intravenous immunoglobulin treatment of Guillain-Barré syndrome

HIV establishes a latent infection in resting CD4(+) T-lymphocytes. A possible strategy to eliminate cellular reservoirs in long-lived, HIV-1-infected quiescent CD4(+) T-lymphocytes might be to add T-cell-activating agents to potent antiretroviral therapy. In this report we describe a patient with Guillain-Barré syndrome treated with high dose intravenous immunoglobulin (IVIG) in addition to antiretroviral therapy. A transiently increased viral load and immunoactivation during the IVIG treatment suggest activation of latently infected cells and increased turnover rate of the latent viral reservoir. HIV replication was controlled with plasma viral load <20 copies/ml, for at least 3 months after antiretroviral treatment interruption. CSF neural markers reflecting degenerative processes in the brain during the symptomatic period and follow-up were also analysed. Very high CSF sulfatide concentrations were found indicating that the pathology involves severe demyelination.We hypothesize that IVIG in this case contributed to an activation of latently infected cells, which led to a transient increase in plasma HIV-1 RNA during the IVIG treatment and a long period of undetectable viral load after antiretroviral treatment interruption. Further, this is the first time, to our knowledge, that detailed CSF findings are described in HIV-1 associated GBS.

Increased serum-GFAP in patients with severe traumatic brain injury is related to outcome

OBJECTIVES

Several studies have established the relevance of S-100 in blood as a marker of brain damage after traumatic brain injury. However, a more specific marker is required and glial fibrillary acidic protein (GFAP) is considered to be a good candidate.

METHODS

In order to assess the increase of GFAP in serum (s-GFAP) after a severe traumatic brain injury (TBI) we collected daily serum samples from 59 patients with severe TBI starting on the day of the trauma. S-GFAP was measured using a sandwich ELISA. The Glasgow outcome scale (GOS) assessed outcome after 1 year.

RESULTS

All but one patient had maximal s-GFAP values above the laboratory reference value (median increased 10-fold). The highest detected levels were seen during the first days after TBI and then decreased gradually. Patients with unfavourable outcome had significantly (p<0.001) higher maximal s-GFAP values in the acute phase compared with patients with favourable outcome. All patients (n=5) with s-GFAP>15.04 microg /L died (reference level<0.15 microg/L). We found no significant difference in the maximal s-GFAP levels of patients with isolated brain injury in comparison with patients with multiple traumas.

CONCLUSION

Serum-GFAP is increased during the first days after a severe traumatic brain injury and related to clinical outcome.

Incidence and pathogenesis of clinical relapse after herpes simplex encephalitis in adults

OBJECTIVES

To study the occurrence of relapse of herpes simplex encephalitis (HSE) and to find out whether soluble activity markers in cerebrospinal fluid (CSF) indicate direct viral or immune- mediated events.

METHODS

A consecutive series of 32 adult survivors of HSE were followed to determine the incidence of clinical relapse of HSE. Four patients had neurological deterioration interpreted as relapsing HSE. Four non-relapsing HSE cases were selected as matched controls. Fifty nine batched, paired CSF and serum samples from the eight HSE patients were analysed for soluble activity markers, predominantly cytokines and mediators (interferon-gamma, soluble CD8, tumour necrosis factor-alpha, and interleukin-10), amount of HSV-DNA and markers of glial and neuronal destruction (neurofilament protein, glial fibrillary acidic protein, S-100-beta, and neuron specific enolase).

RESULTS

Relapse of HSE was diagnosed in 3 of 26 (12 %) acyclovir-treated patients (5 episodes during 6.1 years of followup) and in 1 of 6 vidarabine-recipients. All relapses occurred from 1 to 4 months after acute HSE, except for a second relapse after 3.3 years in one patient. Computer tomography at relapses revealed few abnormalities apart from those found during the primary disease. Intravenous acyclovir and corticosteroids were given for 7-21 days in all the relapse patients. All relapse patients seemed to recover to the pre-relapse condition. HSV-DNA was demonstrated in CSF in all patients during the acute stage but not in any of 13 CSF samples taken during relapse phases. The HSV viral load during the acute stage of HSE was not higher or of longer duration in the relapsing patients than in the non-relapsing HSE controls. The levels of sCD8 were increased in nearly all CSF samples tested with peaks of sCD8 at one month of acute HSE. In all episodes of relapse, sCD8 peaks were detected during the first week at high levels. CSF levels of neuron-specific enolase, S-100 and glial fibrillary acidic protein were markedly lower at relapse than at the acute stage of HSV-1 encephalitis.

CONCLUSION

The lack of demonstrable HSV DNA in CSF, the lack of acute CSF signs and the lack of signs of neural and glia cells destruction indicate that a direct viral cytotoxicity is not the major pathogenic mechanism in relapse. Instead, the pronounced CSF proinflammatory immunological response and the relative lack of CSF anti-inflammatory cytokine IL-10 response suggest immunologically-mediated pathogenicity.

Increased levels of GFAP in the cerebrospinal fluid in three subtypes of genetically confirmed Alexander disease

GFAP levels in the CSF were highly elevated in three genetically confirmed cases of Alexander disease clinically conforming with infantile, early and late juvenile forms. No other CSF abnormalities were detected. Assay of CSF-GFAP may prove to be a rapid and cost-effective screening test in clinical variants of Alexander disease and an indicator of GFAP gene mutations.

Cerebrospinal fluid signs of neuronal damage after antiretroviral treatment interruption in HIV-1 infection

Background

The neurofilament is a major structural component of myelinated axons. Increased cerebrospinal fluid (CSF) concentrations of the light chain of the neurofilament protein (NFL) can serve as a sensitive indicator of central nervous system (CNS) injury. To assess whether interrupting antiretroviral treatment of HIV infection might have a deleterious effect on the CNS, we measured NFL levels in HIV-infected subjects interrupting therapy.

We identified subjects who had CSF HIV RNA concentrations below 50 copies/mL at the time combination antiretroviral therapy was interrupted, and for whom CSF samples were available before and after the interruption.

Results

A total of 8 subjects were studied. The median (range) CSF NFL level at baseline was <125 (<125–220) ng/L (normal <250 ng/L). All 8 subjects exhibited an increase in CSF and plasma HIV RNA after stopping therapy, accompanied by intrathecal immunoactivation as evidenced by CSF lymphocytic pleocytosis (7/8 patients) and increased CSF neopterin concentration (5/6 patients). Three subjects showed a consistent increase in CSF NFL, rising from <125 ng/L to a maximum of 880 (at day 148), 1,010 (day 58) and 10,930 ng/L (day 101). None exhibited new neurological symptoms or signs, or experienced functional deterioration during the period off treatment; of 5 who underwent brief quantitative neurological testing, none showed worsening performance.

Conclusion

These findings suggest that resurgence of active HIV replication may result in measurable, albeit subclinical, CNS injury. Further studies are needed to define the frequency and pathobiological importance of the increase in CSF NFL.

Simultaneous measurement of beta-amyloid(1-42), total tau, and phosphorylated tau (Thr181) in cerebrospinal fluid by the xMAP technology

BACKGROUND

To simultaneously study several biomarkers for Alzheimer disease (AD), we used the xMAP technology to develop and evaluate a multiparametric bead-based assay for quantification of beta-amyloid((1-42)) [Abeta((1-42))], total tau (T-TAU), and hyperphosphorylated tau [P-TAU((181P))] in cerebrospinal fluid (CSF).

METHODS

We compared the new multianalyte assay format with established ELISA techniques for the same proteins. We then performed a clinical study using CSF samples from patients with AD or mild cognitive impairment with progression to AD, healthy controls, and patients with other neurologic disorders.

RESULTS

The INNO-BIA AlzBio3 selectively and specifically measured Abeta((1-42)), T-TAU, and P-TAU((181P)) in the CSF. The new assay format had intra- and interassay CVs <10% for all analytes, even at low concentrations. The measurement range of the new assay was 3 to 4 logs compared with 1 to 2 logs for ELISAs. By plotting the mean of the values obtained in ELISA and the xMAP technology against the difference, we found that a correction factor could be used to convert xMAP results to ELISA values. The clinical study demonstrated that the new multiparametric assay could accurately distinguish patients with AD from patients with other neurologic disorders or control patients, with the diagnostic accuracy reaching recommended consensus criteria for specificity and sensitivity.

CONCLUSION

The new multiparametric method may be able to replace the corresponding ELISA methods.

Neurofilament and glial fibrillary acidic protein in multiple sclerosis

OBJECTIVE

To evaluate levels of neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) in CSF from patients with multiple sclerosis (MS) in relation to clinical progress of the disease.

METHODS

CSF levels of NFL and GFAP were determined by sensitive ELISAs in 99 patients with different subtypes of MS, classified in terms of "ongoing relapse" or "clinically stable disease," and 25 control subjects. Levels were compared with paraclinical data such as immunoglobulin G index and inflammatory cell count in the CSF, and the levels were related to Expanded Disability Status Scale score and progression index at clinical follow-up evaluations later in the disease course.

RESULTS

NFL and GFAP levels were elevated in MS patients as compared with control subjects (p < 0.001). The NFL levels were higher at relapses, whereas GFAP levels were unaffected. High NFL levels correlated with progression in patients with an active relapse (r = 0.49; p < 0.01) and in clinically stable patients (r = 0.29; p < 0.05). GFAP correlated to progression in the total patient cohort (r = 0.24; p < 0.05). Moreover, a strong correlation between NFL levels and inflammatory cell counts was evident in the group of patients with an ongoing relapse (r = 0.52; p = 0.001).

CONCLUSIONS

CSF levels of neurofilament light and glial fibrillary acidic protein may have prognostic value in multiple sclerosis.

Cerebrospinal fluid biomarkers in experimental spinal nerve root injury

STUDY DESIGN

Cerebrospinal fluid biomarkers were evaluated in a setup using established pig models to mimic clinical disc herniation.

OBJECTIVES

To investigate biomarkers for nerve tissue injury, inflammation, and pain in cerebrospinal fluid after mechanical compression and/or nucleus pulposus application to spinal nerve roots.

SUMMARY OF BACKGROUND DATA

The association between mechanical compression, biochemical effects of nucleus pulposus, and nerve root injury in degenerative disc disorders is incompletely investigated.

METHODS

The unilateral S1 nerve root was exposed in 20 pigs. The animals were divided into four groups (n = 5 each): 1) slow-onset mechanical compression with an ameroid constrictor; 2) autologous nucleus pulposus application; 3) mechanical compression plus nucleus pulposus; and 4) sham operation. After 1 week, 6 mL of cerebrospinal fluid was collected, and four structural nerve proteins, neurofilaments, S-100, glial fibrillary acidic protein, neuron-specific enolase, the proinflammatory cytokine interleukin-8, the neurotransmitter nociceptin, and substance P endopeptidase activity were analyzed using immunoassays.

RESULTS

The concentration of neurofilament was increased in the mechanical compression group (17.0 microg/L +/- 5.0) and in the mechanical compression plus nucleus pulposus group (19.8 +/- 12.1 microg/L) compared with the sham group (0.9 +/- 0.9 microg/L) and the nucleus pulposus group (0.4 +/- 0.1 microg/L) (P < 0.01 for both). The concentration of nociceptin was increased significantly in the mechanical compression group (24.0 +/- 8.6 fm/mL) and in the mechanical compression plus nucleus pulposus group (31.2 +/- 6.6 fm/mL) compared with the sham group (7.0 +/- 1.3 fm/mL) (P < 0.05 and P < 0.01, respectively). A correlation was found between concentrations of neurofilament and nociceptin (r = 0.50, P < 0.05). There were no intergroup differences regarding glial fibrillary acidic protein, neuron-specific enolase, S-100, interleukin-8, or substance P endopeptidase activity.

CONCLUSIONS

The present study demonstrates increased concentrations of neurofilament and nociceptin in cerebrospinal fluid after nerve root compression. A simultaneous application of nucleus pulposus did not increase the response.

Marked increase of ?-amyloid(1?42) and amyloid precursor protein in ventricular cerebrospinal fluid after severe traumatic brain injury

Severe traumatic brain injury (TBI) may result in widespread damage to axons, termed diffuse axonal injury. Alzheimer's disease (AD) is characterised by synaptic and axonal degeneration together with senile plaques (SP). SP are mainly composed of aggregated beta-amyloid (Abeta), which are peptides derived from the amyloid precursor protein (APP). Apart from TBI in itself being considered a risk factor for AD, severe head injury seems to initiate a cascade of molecular events that are also associated with AD. We have therefore analysed the 42 amino acid forms of Abeta (Abeta1-42) and two soluble forms of APP (alpha-sAPP and ss-sAPP) in ventricular cerebrospinal fluid (VCSF) and Abeta(1-42) in plasma from 28 patients in a serial samples 0-11 days after TBI. The levels of alpha-sAPP, ss-sAPP and Abeta(1-42) were determined using ELISA assays. After TBI, there was a significant stepwise increase in VCSF-Abeta(1-42) up to 1173 % from day 0-1 to day 5-6 and in VCSF-beta-sAPP up to 2033 % increase from day 0-1 to day 7-11. There was also a slight but significant increase of VCSF-beta-sAPP from day 0-1 to day 5-6 and day 7-11. By contrast, the plasma- Abeta(1-42) level is unchanged after injury. The marked increase in VCSFAbeta(1-42) implies that increased Abeta expression may occur as a secondary phenomenon after TBI with axonal damage. The unchanged level of plasma-Abeta(1-42) in contrast to the marked increase in VCSF-Abeta(1-42) after severe TBI, supports the suggestion that plasma Abeta(1-42) does not reflect Abeta metabolism in the central nervous system (CNS).

CSF levels of neurofilament is a valuable predictor of long-term outcome after cardiac arrest

AIMS

Prognostication of brain damage after cardiac arrest mainly relies on clinical observations. Recently, it has been shown that biochemical markers of brain damage measured in serum aid in this process. In the present study, we wanted to test the usefulness of CSF determinations of a neuronal protein, the neurofilament protein (NFL).

METHODS AND RESULTS

Lumbar punctures were performed during week 2 or 3 in 22 patients surviving cardiac arrests. CSF NFL concentrations were analysed using an ELISA. Levels were increased in cardiac arrest patients. Patients with poor outcome according to the Glasgow outcome scale (GOS), low performance at a mini mental state examination (MMSE) and dependent according to Katz at 1 year follow up had the highest NFL levels. The NFL levels correlated well with anoxia time and coma depth. High positive and negative predictive values, particularly for poor outcome according to GOS were observed.

CONCLUSIONS

Levels of CSF NFL give a reliable measure of the brain damage following cardiac arrest and the levels are highly predictive of poor outcome. This observation urges the development of sensitive serum assays of this marker to be used in the clinical setting.

Neurofilament light protein and glial fibrillary acidic protein as biological markers in MS

OBJECTIVE

To determine if CNS-derived proteins present in the CSF of multiple sclerosis (MS) patients reflect different pathologic processes of MS and if these proteins could be useful as biologic markers of disease activity.

METHODS

Concentrations of the neurofilament light protein (NFL), glial fibrillary acidic protein (GFAP), S100B, and the neuron-specific enolase protein (NSE) were determined in the CSF of 66 MS patients and 50 healthy control subjects with immunoassays.

RESULTS

The mean levels of the NFL were increased during all stages of MS compared with controls (p < 0.001), peaking almost 10 times higher during acute relapses. The highest levels of GFAP were found during the secondary progressive course (p < 0.001) with a strong correlation with neurologic deficits (Expanded Disability Status Scale score, r = 0.73, p < 0.001). No increase of S100B or NSE protein was found in the CSF of MS patients compared with control subjects.

CONCLUSIONS

Increased level of NFL is a general feature of MS, indicating continuous axonal damage during the entire course of the disease with the most profound damage during acute relapses. GFAP may serve as a biomarker for disease progression, probably reflecting the increasing rate of astrogliosis.

Cerebrospinal fluid markers in MS patients and their healthy siblings

In a previous study we found that nine of 47 siblings to multiple sclerosis (MS) patients with a normal neurological examination carry an intrathecal oligoclonal immunopathy with limited specificity, a condition we termed MS immunopathic trait. The purpose of this study is to further characterize the MS immunopathic trait phenotype. We found that the neurofilament light protein (NFL) and glial fibrillary acidic protein (GFAp) concentrations were increased in the group of patients with clinically definite MS (n = 47) in latent or slowly progressive phases. There was no increase in GFAp and NFL in cerebrospinal fluid in the healthy siblings of MS patients (n = 47), nor in the subgroup of these siblings with MS immunopathic trait (n = 9) compared with a group of healthy control subjects (n = 50). Thus, there was no indication of presymptomatic CNS parenchymal involvement in MS immunopathic trait.

Elevated neurofilament levels in neurological diseases

Neurofilaments, a major cytoskeletal constituent of neuronal cells, can be released into the cerebrospinal fluid during several neurodegenerative diseases. By means of a new sensitive ELISA capable of measuring 60 ng/l of neurofilament light, significant elevations were observed for different neurological disorders. Cerebral infarction presented levels of 19800+/-9100 ng/l, amyothropic lateral sclerosis 3600+/-1200 ng/l, 'relapsing-remitting' MS 2500+/-1500 ng/l, extrapyramidal symptoms 1100+/-300 ng/l, late onset AD 300+/-100 ng/l and vascular dementia 1400+/-800 ng/l. In patients with no signs of neurological diseases the upper normal level and cut-off values was determined to be below 100 ng/l. NF-L determinations will be a valuable complement in identifying neuronal degradation and can be used clinically for diagnostic and monitoring purposes.

Biochemical markers of cerebrospinal ischemia after repair of aneurysms of the descending and thoracoabdominal aorta

OBJECTIVE

To investigate the clinical potential of several markers of spinal cord ischemia in cerebrospinal fluid (CSF) and serum during aneurysm repair of the descending thoracic or thoracoabdominal aorta.

DESIGN

Observational study of consecutive patients. Nonblinded, nonrandomized.

SETTING

University hospital thoracic surgical unit.

PARTICIPANTS

Eleven consecutive elective patients.

INTERVENTIONS

Distal extracorporeal circulation and maintenance of CSF pressure <10 mmHg until intrathecal catheter removal.

MEASUREMENTS AND MAIN RESULTS

CSF and serum levels of S100B (and its isoforms S100A1B and S100BB), neuronal-specific enolase (NSE), and the CSF levels of glial fibrillary acidic protein (GFAp) and lactate were determined. Two patients had postoperative neurologic deficit. One with a stroke showed a 540-fold increased GFAp, a 6-fold NSE, and S100B increase in CSF. One with paraplegia had a 270-fold increase in GFAp, a 2-fold increase in NSE, and 5-fold increased S100B in CSF. One patient without deficit increased GFAp 10-fold, NSE 4-fold, and S100B 23-fold in CSF. CSF lactate increased >50% in 6 of 9 patients without neurologic deficit. Serum S100B increased within 1 hour of surgery in all patients without any concomitant increase in CSF. S100A1B was about 70% of total S100B in both serum and CSF in patients with or without neurologic defects. S100B in CSF increased 3-fold in 3 of 9 asymptomatic patients.

CONCLUSIONS

In patients with neurologic deficit, GFAp in CSF showed the most pronounced increase. Biochemical markers in CSF may increase without neurologic symptoms. There is a significant increase in serum S100B from surgical trauma alone without any increase in CSF.

Nervous Tissue Damage Markers in Cerebrospinal Fluid after Cervical Spine Injuries and Whiplash Trauma

Clinical examination is the only tool available to assess the extent of the nerve tissue damage after a spinal cord injury, and it is well known that the reliability of classification based on clinical examination is not satisfactory, especially in cases with incomplete motor injuries. There is a need to evaluate new methods in order to improve the possibilities of classifying and prognosticating spinal cord injuries. Methods for assessing central nervous system (CNS) damage using markers in cerebrospinal fluid (CSF) have recently been developed. Previous studies have reported glial fibrillary acidic protein (GFAp) and neurofilament protein (NFL) levels in non-traumatic diseases in the central nervous system. The present study is the first report of GFAp and NFL levels in CSF after trauma to the cervical spine. Six cases with cord damage and pronounced neurological deficit showed significantly increased concentrations of both GFAp and NFL in the CSF. Patients with tetrapareses showed higher values than those with incomplete injuries. Three of the 17 whiplash cases had increased levels of NFL, but normal GFAp. Assessment of nervous tissue markers in CSF will probably improve possibilities to classify and prognosticate spinal cord injuries and also to evaluate pharmacological intervention. The increased levels of NFL in three whiplash cases indicate neural damage in a proportion of the cases with neurological deficit. Neurological examinations are presently the only tools for grading and prognostication of spinal cord injuries. Assessment of nervous tissue markers in CSF makes it possible to quantify the degree of nerve cell damage after different types of cervical spine injury ranging from spinal cord lesions to whiplash injuries.

Regional oxygenation and systemic inflammatory response during cardiopulmonary bypass: influence of temperature and blood flow variations

OBJECTIVE

To evaluate the role of target temperature (28 degrees or 34 degrees C) in cardiac surgery on regional oxygenation during hypothermia and rewarming and systemic inflammatory response.

DESIGN

Prospective, controlled, and randomized clinical study.

SETTING

University hospital.

PARTICIPANTS

Elderly patients (mean age 70 +/- 2 years) with acquired heart disease with an anticipated bypass time exceeding 120 minutes (n = 30).

INTERVENTIONS

The patients were cooled to either 28 degrees C (n = 15) or 34 degrees C (n = 15). At hypothermia, bypass blood flow was reduced twice from full flow (2.4 L/min/m(2) body surface area [BSA]) to 2.0 L/min/m(2).

MEASUREMENTS AND MAIN RESULTS

Hepatic and jugular venous oxygen tension and saturation were higher at 28 degrees C than at 34 degrees C. In comparison with the preoperative values, at 28 degrees C hepatic venous values were higher; whereas at 34 degrees C, they were lower. The reduction of pump blood flow during hypothermia, from 2.4 to 2.0 L/min/m(2)was accompanied by reductions of central, jugular, and hepatic oxygenation at both target temperatures. During rewarming, central and regional venous oxygenation decreased irrespective of the preceding temperature. The decrease was most pronounced in hepatic venous blood, with the lowest individual values <10%. Serum concentrations of C3a and IL-6 increased during hypothermia and increased further during rewarming irrespective of the preceding temperature.

CONCLUSION

During cardiopulmonary bypass, hypothermia at 28 degrees C increases regional and central venous oxygenation better than at 34 degrees C. In contrast, venous oxygenation decreases during rewarming irrespective of the preceding temperature. No significant difference in the systemic inflammatory response associated with target temperature was detected.

Cerebrospinal fluid Abeta42 is reduced in multiple system atrophy but normal in Parkinson's disease and progressive supranuclear palsy

The 42-amino-acid isoform of beta-amyloid Abeta42 in the cerebrospinal fluid (CSF) has recently been proposed as a biochemical marker for Alzheimer's disease (AD) and subcortical white-matter dementia (SWD). In both of these conditions, concentration of CSF-Abeta42 is reduced. We quantified CSF-Abeta42 from patients fulfilling strict clinical criteria for multiple system atrophy (MSA; n = 36), Parkinson's disease (PD; n = 48) and progressive supranuclear palsy (PSP; n = 15). The study groups were consecutively recruited among patients referred to a movement disorder unit, and 32 healthy, age-matched volunteers were used as controls. The CSF concentration of Abeta42 was significantly reduced in the MSA group (P < 0.001), whereas the PD and PSP groups did not differ from controls. On an individual basis, low content of Abeta42 was seen in 9 MSA patients regardless of age and disease duration. Three PD patients with long disease duration also had low concentrations but all PSP patients were normal. We conclude that the reduced CSF-Abeta42 concentration may be a clue to the pathogenesis of MSA. There is a decreased production, or more possible, an increased consumption of CSF-Abeta42. The analysis of this protein may also become a supplement to the clinical differentiation of parkinsonian syndromes in a movement disorder unit.

Bradycardic response during submersion in infant swimming

The diving response involves reflex bradycardia, apnoea and peripheral vasoconstriction and is known to exist in human infants. The response diminishes with increasing age and has been reported to disappear by the age of 6 mo. This study was performed to analyse the physiological events during natural diving of full-term healthy infants and describe how these events alter with maturation. Thirty-six infants were studied during diving exercises in infant swimming. All of the infants who participated showed an immediate decrease in heart rate when submerged. On average, the heart rate decreased by 25% (range -5.0% to -50.7%, p <0.0001). The bradycardia was sustained during the dive and for some seconds afterwards. The response was often followed by a tachycardia as the bradycardia ceased. A decline of reflex bradycardia was observed with increasing age (p = 0.03), but the response was still clearly evident in infants over the age of 6 mo.

CONCLUSION

This study demonstrates the existence of a diving response in infants, which includes an immediate bradycardic response, suggesting vagal mediation. Although the bradycardic response gradually decreases, the study shows that a clear-cut response exists in children older than has previously been reported.

Neurological signs are common in patients with urodynamically verified "idiopathic" bladder overactivity

Overactive bladder dysfunction is an expression of defective neuromuscular control of the lower urinary tract. The causes and the way to classify this problem are currently under debate. In some patients the overactive bladder is one sign of a neurological disorder, in so called "idiopathic detrusor instability" the cause is less obvious. That an overactive bladder has a neurogenic cause is a reasonable hypothesis. We made a detailed neurological investigation in 45 patients with idiopathic overactive bladder. Cerebrospinal fluid (CSF) was examined and blood tests for vitamin B(12)and folic acid deficiency were checked, too. In 37 of the 45 patients (82%) pathological signs were observed in the neurological tests. The most common finding was central or peripheral paresis of the legs appearing in 24 patients (53%). Of the 45 patients, eight received a neurological diagnosis, definite or possible MS or dorsal column sensation neuropathy. The results of this study give an indication of the importance of the neurological examination and suggest that neuropathy might not be uncommon in patients with so-called idiopathic detrusor instability. This also invites to reconsideration of the current classification. It is possible that a new classification based on a functional view could provide a better fundament in the search of etiologic and pathogenetic factors and also guide in the selection of the treatment most optimal for the individual patient.

Monoclonal antibodies selective for low molecular weight neurofilaments

Neurofilaments are necessary for the maintenance of axonal caliber and structural organization of nerve cells. The low molecular weight form of neurofilament, the neurofilament light protein, which serves as the core of the filament, was used as immunogen for generation of hybridomas with selective reactivity with this form of the filament. Six hybridomas, out of approximately 100 tested clones, were highly discriminatory. All involved epitopes were localized to the rod region of the antigen, as determined by alpha-chymotrypsin digestion of the purified filament and enzymatic peptide mapping. Synthetic peptides (20 mers) covering the entire rod region did not react with the antibodies. A phage display peptide library was used to identify four consensus sequences for the antibodies. The results indicate that all epitopes were of conformational type. Pair-wise BIAcore data furthermore indicated that the epitopes were independent. The access to such specific reagents is a prerequisite for further elucidation of the biology of the low molecular weight form of neurofilaments proteins.