Induced hypothermia in experimental pneumococcal meningitis

Pneumococcal meningitis resulting from Streptococcus pneumoniae has a death rate of 28% in adults. In severe head injury and stroke, inflammatory changes and intracranial hypertension are improved by induced hypothermia, which also is neuroprotective. We hypothesized that moderate hypothermia ameliorates inflammatory changes in experimental pneumococcal meningitis. Wistar rats were cooled systemically, and meningitis was induced by pneumococcal cell wall components. The increase of regional cerebral blood flow in the meningitis animals was blocked by hypothermia at 6 hours. The reduction of intracranial pressure correlated with temperature. The influx of leukocytes into the cerebrospinal fluid and levels of tumor necrosis factor alpha in the cerebrospinal fluid were decreased. Cooling the animals 2 hours after meningitis induction to 30.5 degrees C was also protective. We conclude that hypothermia is a new adjuvant approach to reduce meningitis-induced changes, in particular intracranial pressure, in the early phase of the disease.

Multiple sclerosis is associated with an imbalance between tumour necrosis factor-alpha (TNF-alpha)- and IL-10-secreting blood cells that is corrected by interferon-beta (IFN-beta) treatment

The up-regulated B cell responses detectable in cerebrospinal fluid (CSF) and the augmented myelin antigen-specific T cell responses observed in the CSF as well as systematically in patients with multiple sclerosis (MS) suggest the involvement of cytokines in disease development and perpetuation. Here we report on the parallel involvement of TNF-alpha, IL-6, IFN-gamma and IL-10 in MS and controls, using enzyme-linked immunospot (ELISPOT) assays to detect and enumerate cytokine-secreting mononuclear cells (MNC) prepared from blood and, for IL-6 and IL-10, from CSF without in vitro stimulation. MS is associated with elevated levels of TNF-alpha-secreting blood MNC when compared with levels in groups of control patients with myasthenia gravis (MG) and other neurological diseases (OND) or healthy subjects. This elevation was confined to patients with untreated MS and not present in those examined during ongoing treatment with IFN-beta. Untreated patients with MS had lower numbers of IL-10-secreting blood MNC compared with the three control groups. In patients undergoing treatment with IFN-beta, numbers of IL-10-secreting cells were in the same range as in controls. Normalization of TNF-alpha from elevated, and of IL-10 from decreased levels could be one reason for the beneficial effects of IFN-beta in MS, although it remains to be shown whether these changes reflect phenomena primarily involved in MS pathogenesis or secondary changes. In CSF, levels of IL-10-secreting cells were higher than in blood in both MS and OND, with no difference between these groups. Systemic aberrations of IL-6 and IFN-gamma and of IL-6 in CSF in MS versus controls were only minor, irrespective of treatment with IFN-beta.

Traumatic brain injury elevates the Alzheimer's amyloid peptide A beta 42 in human CSF. A possible role for nerve cell injury

The increased risk for Alzheimer's Disease (AD) associated with traumatic brain injury (TBI) suggests that environmental insults may influence the development of this age-related dementia. Recently, we have shown that the levels of the beta-amyloid peptide (A beta 1-42) increase in the cerebrospinal fluid (CSF) of patients after severe brain injury and remain elevated for some time after the initial event. The relationships of elevated A beta with markers of blood-brain barrier (BBB) disruption, inflammation, and nerve cell or axonal injury were evaluated in CSF samples taken daily from TBI patients. This analysis reveals that the rise in A beta 1-42 is best correlated with possible markers of neuronal or axonal injury, the cytoskeletal protein tau, neuron-specific enolase (NSE), and apolipoprotein E (ApoE). Similar or better correlations were observed between A beta 1-40 and the three aforementioned markers. These results imply that the degree of brain injury may play a decisive role in determining the levels of A beta 1-42 and A beta 1-40 in the CSF of TBI patients. Inflammation and alterations in BBB may play lesser, but nonetheless significant, roles in determining the A beta level in CSF after brain injury.

Lack of endotoxin tolerance with respect to TNF alpha production in the subarachnoid space

To study endotoxin tolerance in the subarachnoid space 0.1 mg of endotoxin derived from Neisseria meningitidis was injected intracisternally into rabbits on 2 consecutive days. On day 1 the maximum peak level of TNF alpha was 7 ng/ml 2 h after injection, whereas on day 2 the highest levels were 3.6 ng/ml and 3.7 ng/ml, respectively, 1 and 2 h after injection. Pretreatment with intravenous endotoxin 5 or 21 h before consecutive intracisternal endotoxin did not affect the cerebrospinal fluid (CSF) levels of TNF alpha. In contrast, there was a marked endotoxin tolerance with respect to TNF alpha in the systemic circulation. Cells appearing in the CSF 5, 12 and 20 h after intracisternal injection of endotoxin were harvested, cultured, and then stimulated with 0.1 mg/ml of endotoxin. In 10 experiments a marked TNF alpha production in the range 10-70 ng/ml was detected in the supernatants, whereas unstimulated cells did not produce TNF alpha. We conclude that tolerance to endotoxin does not develop in the subarachnoid space as evaluated by the present experimental design. The pattern of TNF alpha production and endotoxin tolerance is distinctly different in the subarachnoid space and systemic circulation.

Matrix metalloproteinases contribute to brain damage in experimental pneumococcal meningitis

The present study was performed to evaluate the role of matrix metalloproteinases (MMP) in the pathogenesis of the inflammatory reaction and the development of neuronal injury in a rat model of bacterial meningitis. mRNA encoding specific MMPs (MMP-3, MMP-7, MMP-8, and MMP-9) and the inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) were significantly (P < 0.04) upregulated, compared to the beta-actin housekeeping gene, in cortical homogenates at 20 h after infection. In parallel, concentrations of MMP-9 and TNF-alpha in cerebrospinal fluid (CSF) were significantly increased in rats with bacterial meningitis compared to uninfected animals (P = 0.002) and showed a close correlation (r = 0.76; P < 0. 001). Treatment with a hydroxamic acid-type MMP inhibitor (GM6001; 65 mg/kg intraperitoneally every 12 h) beginning at the time of infection significantly lowered the MMP-9 (P < 0.02) and TNF-alpha (P < 0.02) levels in CSF. Histopathology at 25.5 +/- 5.7 h after infection showed neuronal injury (median [range], 3.5% [0 to 17.5%] of the cortex), which was significantly (P < 0.01) reduced to 0% (0 to 10.8%) by GM6001. This is the first report to demonstrate that MMPs contribute to the development of neuronal injury in bacterial meningitis and that inhibition of MMPs may be an effective approach to prevent brain damage as a consequence of the disease.

Expression of TNFalpha and TGFbeta1 in Guillain-Barré syndrome: correlation of a low TNFalpha-/TGFbeta1-mRNA ratio with good recovery and signs for immunoregulation within the cerebrospinal fluid compartment

In the pathogenesis of Guillain-Barré syndrome (GBS) a dysregulation of cytokines is supposed. The protein concentration and mRNA expression of TNFalpha and TGFbeta1 were investigated in cerebrospinal fluid (CSF) and blood in 10 patients with GBS. TNFalpha-mRNA was increased at the beginning of the disease and demonstrated a decline during the time course (P = 0.001). The level of TNFalpha protein was elevated in only a few patients. TGFbeta1-mRNA (P = 0.001) and the active TGFbeta1 protein (P < 0.05) increased during the course of GBS, and the level of total TGFbeta1 protein was temporarily elevated (P = 0.005). A low ratio of TNFalpha-/TGFbeta-mRNA expression correlated to a good clinical course (P < 0.05). The results indicate an association of TNFalpha with disease activity. TGFbeta1 seems to terminate and limit the inflammatory reactions and to promote the healing course of GBS. In addition the investigations show that in GBS immunoregulatory mechanisms also take place in the CSF compartment itself and that CSF cells are involved in the production of pro-inflammatory as well as immunosuppressive cytokines.

Cerebrospinal fluid tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-8 as diagnostic markers of cerebrospinal fluid infection in neurosurgical patients

OBJECTIVE

To evaluate whether cerebrospinal fluid concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, or IL-8 may be used as diagnostic markers for the differential diagnosis of aseptic vs. bacterial meningitis and/or ventriculitis in neurosurgical patients.

DESIGN

Prospective, observational study.

SETTING

University teaching hospital.

SUBJECTS

A total of 112 cerebrospinal fluid samples from 14 asymptomatic patients with normal cerebrospinal fluid after neurosurgery, 27 asymptomatic and 19 symptomatic patients with postneurosurgical aseptic meningitis, 32 patients with postneurosurgical cerebrospinal fluid infection, and 20 with severe subarachnoid and/or cerebral hemorrhage.

MEASUREMENTS AND MAIN RESULTS

Specific ELISA kits were used to analyze TNF-alpha, IL-1beta, IL-6, and IL-8 concentrations on cerebrospinal fluid samples. Elevations in cerebrospinal fluid concentrations of TNF-alpha, IL-1beta, IL-6, and IL-8 were induced by different diseases or neurosurgical procedures, but cerebrospinal fluid bacterial infection induced the highest concentrations. To discriminate between aseptic cerebrospinal fluid pleocytosis and cerebrospinal fluid infection with a specificity of 95%, cerebrospinal fluid leukocyte count >1700/mL, TNF-alpha >150 pg/mL, and IL-1beta >90 pg/mL showed sensitivities of 51%, 74%, and 90%, respectively. Sufficiently sensitive and specific cutoff points could not be found for cerebrospinal fluid IL-6 or IL-8.

CONCLUSION

Cerebrospinal fluid IL-1beta appears to be the best biochemical marker of cerebrospinal fluid infection in neurosurgical patients.

Blood interleukin-6 and tumor necrosis factor-alpha elevation after intracerebroventricular injection of Escherichia coli endotoxin in the rat is determined by two opposing factors: peripheral induction by LPS transferred from brain to blood and inhibition of peripheral response by a brain-mediated mechanism

Following intracerebroventricular injection of LPS in rats, IL-6 and TNF-alpha appear in peripheral blood. To determine whether these changes are mediated by passage of the injected LPS from the brain to the blood, the time course of appearance in blood of bioactive LPS after intracerebroventricular injection was compared with the time course of appearance of IL-6 and of TNF-alpha in blood. Bioactive LPS was detected 30 min after intracerebroventricular injection, the first time interval tested. TNF-alpha appeared in peripheral blood at 30 min, IL-6 at 60 min and both cytokines as well as LPS achieved highest levels at 120 min. To determine pharmacokinetics of LPS transfer from brain to blood more precisely, radioiodinated LPS was injected intracerebroventricularly. (125)I-LPS was detected in blood as early as 5 min after intracerebroventricular injection, reached peak levels at about 2 h, and was transferred from brain to blood at a rate corresponding to bulk flow (% of brain content per min was 1.40 +/- 0.58 and 1.00 +/- 0.21% in series 1 and 2, respectively). 70.0% of total injected LPS had entered blood by 4 h. However, when administered intravenously (by a programmed pump) at the same rate that it enters the blood after intracerebroventricular injection LPS induced a much greater cytokine response than when given intracerebroventricularly. This paradoxical response was shown in further studies to be due to the simultaneous central inhibitory effect of LPS; coinjection of intracerebroventricular LPS markedly reduced the peripheral cytokine response to intravenous LPS infusion.

Cerebrospinal fluid nitric oxide levels in childhood bacterial meningitis

The role of nitric oxide (NO) in childhood bacterial meningitis was investigated by determining the levels of nitrate/nitrite, stable end products of NO metabolism, in cerebrospinal fluid (CSF). Eighteen children with bacterial meningitis and 18 as a control group were included in the study. Mean (+/- SD) CSF nitrate/nitrite levels were 27.6 +/- 26 micromol/l in the bacterial meningitis group and 3.2 +/- 1.8 micromol/l in the control group (p = 0.0005). We found no correlation between CSF nitrate/nitrite levels and CSF white blood cell count (r = 0.22), protein (r = 0.26) or tumour necrosis factor alpha (TNF-alpha) levels (r = 0.046), but a moderate negative correlation between CSF nitrate/nitrite and glucose levels (r = -0.46).

IL-10 levels in cerebrospinal fluid and serum of patients with severe traumatic brain injury: relationship to IL-6, TNF-alpha, TGF-beta1 and blood-brain barrier function

Controlling the extent of inflammatory responses following brain injury may be beneficial since posttraumatic intracranial inflammation has been associated with adverse outcome. In order to elucidate the potential role of anti-inflammatory mediators, the production of interleukin-10 (IL-10) was monitored in paired cerebrospinal fluid (CSF) and serum of 28 patients with severe traumatic brain injury (TBI) and compared to control samples. The pattern of IL-10 was analyzed with respect to the patterns of IL-6, tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) in both fluids during a time period of up to 22 days. In parallel, the function/dysfunction of the blood-brain barrier (BBB) was monitored using the CSF-/serum-albumin quotient (Q(A)) and compared to intrathecal cytokine levels. Mean IL-10 concentration in CSF was elevated in 26 out of 28 TBI patients (range: 1.3-41.7 pg/ml) compared to controls (cut-off: 1.06 pg/ml), whereas only seven patients had elevated mean IL-10 concentration in serum (range: 5.4-23 pg/ml; cut-off: 5.14 pg/ml). The time course of IL-10 was similar in both fluids, showing a peak during the first days and a second, lower rise in the second week. Intrathecal IL-10 synthesis is hypothesized since CSF-IL-10 levels exceeded serum-IL-10 levels in most of the patients, IL-10-index (CSF/serum-IL-10/QA) was elevated in 23 individuals, and elevation of CSF-IL-10 showed to be independent from severe BBB dysfunction. Neither CSF nor serum IL-10 values correlated with the dysfunction of the BBB. IL-10, IL-6 and TGF-beta1 showed similar patterns in CSF over time, whereas rises of TNF-alpha corresponded to declines of IL-10 levels. Our results suggest that IL-10 is predominantly induced intrathecally after severe TBI where it may downregulate inflammatory events following traumatic brain damage.

Assessing multiple sclerosis activity: is the in vitro production of tumor necrosis factor-alpha, interleukins 2, 6, 4, and 10, and immunoglobulin G of value?

Tumor necrosis factor (TNF) alpha, interleukins (IL) 2, 4, 6, and 10, and IgG oligoclonal bands (IgG OB) in vitro production was assessed, after whole-blood stimulation with lipopolysaccharide or concanavalin A, in 61 patients presenting with relapsing-remitting, relapsing-progressive, or chronic progressive multiple sclerosis. Multiple sclerosis patients were receiving no treatment or azathioprine (AZA), cyclosporin, cyclophosphamide, subcutaneous interferon (IFN) beta 1 a, or corticosteroids (CST). Statistical correlations significantly showed that: (a) AZA lowers TNF-alpha (P = 0.002) and increases IL-4 production (P = 0.0024), and IFN-beta 1 a increases TNF-alpha and decreases IL-4 levels; (b) CST has a negative effect on TNF-alpha, IL-6, and IL-4 synthesis; and (c) AZA, IFN-beta 1 a, and CST diminish IgG OB synthesis (P = 0.001). Although our study of the dynamics of TNF-alpha, IL-2, IL-4, IL-6, and IL-10 in vitro production generally found no statistically significant correlations (partly explained by the limited number of values in the various groups), IL-6 was shown to drop during the periods surrounding relapse (P = 0.05) in the absence of treatment, while TNF-alpha (P = 0.04) and IL-6 (P < 0.05) dropped before exacerbation in the presence of AZA. In vitro production of TNF-alpha was closely and positively correlated with that of IL-6, independently of clinical features. The enhanced production of IL-10 detected before or at relapse with AZA and IFN-beta 1 a (trends) may interfere with initiation of the immune reaction and with the development of new CNS lesions. Some discrepancies with previously published results stress the difficulties in studying the state of stimulation of different populations of leukocytes by using a variety of in vitro stimuli and in establishing a correlation between mRNA studies and the amount of final or active protein produced.

Tumor necrosis factor-alpha and its soluble receptors in plasma and cerebrospinal fluid of multiple sclerosis patients treated with methylprednisolone

Demyelination is the main pathological feature of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. Tumor necrosis factor-alpha (TNF-alpha) can cause myelin damage and contribute to MS pathogenesis. We measured plasma and cerebrospinal fluid (CSF) levels of TNF-alpha and its soluble receptors, TNF-sRp55 and TNF-sRp75, in 18 patients with active MS, and in neurological and healthy controls. The same determinations were repeated on plasma and on CSF samples that were collected after the MS patients had ended a six-day treatment with high-dose methylprednisolone (MP). Pre- and post-treatment plasma and CSF TNF-alpha levels, when detectable, and those of TNF-sRp75, did not vary, and were similar to those of controls. CSF TNF-sRp55 levels were higher in acute MS patients than in controls. Post-treatment CSF TNF-sRp55 levels were higher than in the active phase of the disease. The MS patients, who clinically improved, tended to have the highest CSF TNF-sRp55 levels. The increase was due to intrathecal TNF-sRp55 synthesis. Although it is involved in MS pathogenesis, TNF-alpha is not detectable in plasma or in CSF samples from MS patients in various phases of the disease. A better marker of disease activity seems to be CSF TNF-sRp55 levels. The increased CSF levels of TNF-sRp55 in response to MP circumstantially suggest that this receptor could partially account for the beneficial effects of MP in acute MS.

Reduced concentrations of HIV-RNA and TNF-alpha coexist in CSF of AIDS patients with progressive multifocal leukoencephalopathy

OBJECTIVES

To confirm reduced human immunodeficiency virus type-1 (HIV-1) burden in the CSF of patients with progressive multifocal leukoencephalopathy (PML) and to verify whether this viral load coincides with the absence of inflammatory changes in the CSF.

METHODS

Paired CSF and plasma samples from 17 patients with PML, 26 with non-PML cerebral opportunistic infections, nine with HIV-1 leukoencephalopathy (HIVE), and 12 neurologically asymptomatic AIDS patients were subjected to HIV-RNA titration. Tumour necrosis factor (TNF)-alpha was also measured and the CSF albumin: serum albumin ratio (Q(Alb)) was calculated.

RESULTS

The CSF HIV-1 burden of patients with PML did not differ from that of neurologically asymptomatic patients (p=0.21), but was significantly lower than CSF burden of the remaining patients (non-PML opportunistic infections, p<0.001; HIVE, p<0.001). Q(Alb) was normal for all neurologically asymptomatic patients, for 86.6% patients with PML, and 62.5% patients with HIVE (p=0.09). Q(Alb) was altered in 91.6% patients with non-PML opportunistic infections. TNF-alpha in CSF was higher in patients with non-PML opportunistic infections (p<0.001) and those with HIVE (p<0.001) than in patients with PML who consistently had TNF-alpha concentrations<10 pg/ml.

CONCLUSIONS

These results, while indicating a reduced HIV replication in CSF of patients with PML which might serve as a disease marker, emphasise the increased CSF HIV-RNA concentration in patients with HIVE and patients with non-PML opportunistic infections. Low concentrations of HIV-RNA in CSF coincide with reduced TNF-alpha concentrations, possibly due to particular features of PML compared with other opportunistic infections as it develops without detectable inflammatory changes in the CSF.

Cytokine profiles in the central nervous system and the spleen during the early course of experimental African trypanosomiasis

Cytokines are important signalling proteins, which have been shown to contribute to immunopathogenesis of several inflammatory and infectious diseases such as African trypanosomiasis. The present study was conducted in order to evaluate the early induction of five potential cytokines in the central nervous system (CNS) and spleens from Trypanosoma brucei brucei (T. b. brucei)-inoculated and uninfected control Sprague-Dawley rats. In brain, choroid plexus and spleen, cytokine levels were examined by in situ hybridization and immunohistochemistry, while ELISA was used to measure cytokine levels in cerebrospinal fluid (CSF). Our results showed that interferon (IFN)-gamma and transforming growth factor (TGF)-beta were highly expressed in all compartments, but low interleukin (IL)-4, IL-10 and tumour necrosis factor (TNF)-alpha mRNA levels were registered. The pattern of these cytokines is in context with the severity of the disease because (i) IFN-gamma was previously demonstrated to promote parasite growth (ii) TNF-alpha was previously demonstrated to kill the parasites and (iii) IL-4 was previously demonstrated to promote antibody production necessary for elimination of the infection. These data support the hypothesis that cytokines may have a role in developing the disease either by enhancing the parasite growth or by suppressing the immune response.

HIV type 1 Nef protein is a viral factor for leukocyte recruitment into the central nervous system

Recombinant HIV-1 Nef protein, but not Tat, gp120, and gp160, provoked leukocyte recruitment into the CNS in a rat model. The strong reduction of bioactivity by heat treatment of Nef, and the blocking effect of the mAb 2H12, which recognizes the carboxy-terminal amino acid (aa) residues 171-190 (but not of mAb 3E6, an anti-Nef Ab of the same isotype, which maps the aa sequence 168-175, as well as a mixture of mAbs to CD4) provided evidence for the specificity of the observed Nef effects. Using a modified Boyden chamber technique, Nef exhibited chemotactic activity on mononuclear cells in vitro. Coadministration of the anti-Nef mAb 2H12, as well as treatment of Nef by heat inhibited Nef-induced chemotaxis. Besides soluble Nef, chemotaxis was also induced by a Nef-expressing human astrocytoma cell line, but not by control cells. These data suggest a direct chemotactic activity of soluble Nef. The detection of elevated levels of IL-6, TNF-alpha, and IFN-gamma in rat cerebrospinal fluid 6 h after intracisternal Nef injection hint at the additional involvement of indirect mechanisms in Nef-induced leukocyte migration into rat CNS. These data propose a mechanism by which HIV-1 Nef protein may be essential for AIDS neuropathogenesis, as a mediator of the recruitment of leukocytes that may serve as vehicles of the virus and perpetrators for disease through their production of neurotoxins.

Little benefit from mild hypothermia therapy for severely head injured patients with low intracranial pressure

OBJECT

This study was performed to determine whether mild hypothermia therapy is essential for the treatment of severely head injured patients in whom intracranial pressure (ICP) can be maintained below 20 mm Hg by using conventional therapies.

METHODS

Sixteen consecutive severely head injured patients fulfilled the following criteria: the patient's ICP was maintained below 20 mm Hg by using fluid restriction, hyperventilation, and high-dose barbiturate therapy; and the patient had a Glasgow Coma Scale score of 8 or less on admission. After conventional therapies had been applied, the patients were divided randomly into two groups: the mild hypothermia group (HT group; eight patients) and the normothermia group (NT group; eight patients). The HT group received mild hypothermia (intracranial temperature 34 degrees C) therapy for 48 hours followed by rewarming at 1 degree C per day for 3 days, whereas the NT group received normothermia (intracranial temperature 37 degrees C) therapy for 5 days. Specimens of cerebrospinal fluid (CSF) taken from an intraventricular catheter every 24 hours were analyzed for the presence of excitatory amino acids ([EAAs] glutamate, aspartate, and glycine) and cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-6, IL-8, and IL-10). The two groups did not differ significantly in patient age, neurological status, or level of ICP. There were no significant differences in daily changes in CSF concentrations of EAAs and cytokines between the two groups. The incidence of pneumonia was slightly higher in the HT group compared with the NT group (p = 0.059). The incidence of diabetes insipidus associated with hypernatremia was significantly higher in the HT group compared with that in the NT group (p < 0.01). The two groups did not differ with respect to their clinical outcomes.

CONCLUSIONS

The authors recommend normothermia therapy for the treatment of severely head injured patients in whom ICP can be maintained at lower than 20 mm Hg by using conventional therapies, because mild hypothermia therapy does not convey any advantage over normothermia therapy in such patients.

Detection of influenza virus RNA by reverse transcription-PCR and proinflammatory cytokines in influenza-virus-associated encephalopathy

Eleven children with acute encephalopathy associated with an influenza virus infection were treated during the 1997-1998 influenza season. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the viral genome in peripheral blood and cerebrospinal fluid (CSF) samples. The results were compared with those of control influenza patients without neurological complications. Viral RNA was detected only in the peripheral blood mononuclear cells of one patient with influenza-virus-associated encephalopathy (1 of 9; 11%) and in the CSF of another patient (1 of 11;9%). RT-PCR was negative in the blood of all the controls, but the percentage of RT-PCR-positive samples in the two groups was not significantly different. Cytokines and soluble cytokine receptors in plasma and CSF were then quantified using an enzyme-linked immunosorbent assay. The CSF concentrations of soluble tumor necrosis factor receptor-1 were elevated in two patients and interleukin-6 (IL-6) was elevated in one patient with influenza-virus-associated encephalopathy. On the other hand, the plasma concentrations of IL-6 were elevated in four of nine patients. The number of encephalopathy patients who had elevated plasma concentrations of IL-6 100 pg/ml was significantly higher than that of controls (P= .01). In conclusion, the infrequent detection of the viral genome in the CSF and blood showed that direct invasion of the virus into the central nervous system was an uncommon event. Proinflammatory cytokines and soluble cytokine receptors may mediate the disease. The high plasma concentration of IL-6 could be an indicator of the progression to encephalopathy.

Cerebrospinal fluid cytokine levels and dexamethasone therapy in bacterial meningitis

OBJECTIVES

cerebrospinal fluid (CSF) levels of interleukin (IL)-1 beta and tumor necrosis factor (TNF) alpha were measured to assess the effect and application of dexamethasone (Dex) therapy for bacterial meningitis.

METHODS

associations between clinical findings and CSF parameters were first investigated, and prognosis was compared between 25 patients with Dex and 12 without Dex therapy.

RESULTS

patients with the presence of disturbed consciousness showed higher CSF levels of TNF alpha (mean: 3015 pg/ml) or protein (mean: 215 mg/dl) than those without it (both, P < 0.O5). Simultaneous increase of TNF alpha (> 1000 pg/ml) and protein (> 100 g/dl) was observed in 80%, of patients with profoundly disturbed consciousness. Patients with Dex therapy presented higher TNF alpha/protein levels at diagnosis than those without Dex therapy (P < 0.05). Despite worse conditions at diagnosis, only one of 14 Dex-treated patients whose initial CSF TNF alpha levels exceeded 1000 pg/ml developed deafness. On the other hand, two of four patients without Dex therapy who had the same TNF alpha level suffered from psychomotor retardation. The differences in the frequency of sequelae between those with and without Dex therapy were significant in patients showing high TNF alpha level (P < O.05), but not in those showing high CSF levels of IL-1 beta or protein. The logistic regression analysis indicated that high CSF protein level (P < O.0001), or no Dex therapy (P=0.0001) was the independent risk factor for sequelae.

CONCLUSIONS

although the study number was small, our observations suggested that CSF TNF alpha/protein levels reflected the neurologic severity, and implied that early Dex therapy might be beneficial for patients with prominently high TNF alpha levels.

[Immunological markers of disease activity in the course of 2-CDA treatment of multiple sclerosis]

52 clinically definite multiple sclerosis (MS) patients were treated with subcutaneous injection of 5 mg 2-CDA in 5 consecutive days. The injection courses were repeated 6 times in one month interval. The MRI pattern and immunological markers were studied in serum and CSF before and after 6 months of treatment. The obtained results suggest that treatment with 2-CDA has not any significant effect on humoral immunological events in multiple sclerosis, what is in contrast to some normalization of cellular immunopathological processes.

Intracerebral production of tumor necrosis factor-alpha, a local neuroprotective agent, in Alzheimer disease and vascular dementia

The local pattern of proinflammatory cytokine release was studied in Alzheimer disease (AD) and vascular dementia (VAD), by measuring intrathecal levels of IL-1 beta, IL-6, TNF-alpha, and its naturally occurring antagonists, soluble TNF receptors I and II. The cytokine levels were related to neuronal damage, as measured by the intrathecal tau concentration, to cerebral apoptosis assessed by levels of Fas/APO-1 and bcl-2, and to clinical variables. In vitro analysis was performed to study the effect of TNF-alpha on the production of bcl-2, an antiapoptotic factor, by human neuronal cells. Patients with both AD and VAD displayed significantly higher intrathecal levels of TNF-alpha compared to controls. In addition, patients with AD showed significantly negative correlations between the intrathecal levels of TNF-alpha and the levels of Fas/APO-1 as well as of tau protein. The level of bcl-2 in supernatants of TNF-alpha-exposed cultures of human neuronal cells was up to three times higher than in control supernatants. Our study demonstrates intrathecal production of TNF-alpha in patients with dementias, suggesting that this cytokine may have a neuroprotective role in these neurodegenerative conditions as evidenced by negative correlations between this cytokine and (i) levels of intrathecal Fas/APO-1 and (ii) levels of tau protein, both parameters closely related to brain damage. Our in vitro data suggest that TNF-alpha exerts its neuroprotective effect by stimulating neuronal cells to express bcl-2, a molecule which downregulates apoptosis.

[Investigation of mechanisms of neuro-protective effect of semax in acute period of ischemic stroke]

Semax is the first domestic nootropic drug of an unexhausted type from the group of neuropeptides. In experimental studies it showed angioprotective, antihypoxic and neurotrophic activity in the doses 100-150 micrograms/kg. A combined clinical-electrophysiologic study revealed its high efficiency in acute ischemic stroke. A clinical trial was performed of immunobiochemical mechanisms of neuroprotective properties of Semax in acute period of ischemic stroke. A retrospective comparative clinicoimmunobiochemical analysis provided objective data on the molecular level on activating influence of Semax on antiinflammatory postischemic reactions in the brain. Shifting neuromediatory balance toward a prevalence of the antiinflammatory agents (interleukin-10, tumor necrosis factor-alpha) over the factors maintaining the inflammation (interleukin-8, C-reactive protein).

Unchanged levels of interleukins, neopterin, interferon-gamma and tumor necrosis factor-alpha in cerebrospinal fluid of patients with dementia of the Alzheimer type

Several histopathological studies suggest that amyloidogenesis in dementia of the Alzheimer type is accompanied by activated glia and glia-derived cytokines, leading to chronic, self-propagating, cytokine-mediated molecular and cellular reactions. As studies regarding inflammatory changes in cerebrospinal fluid of patients with dementia of the Alzheimer type has been inconclusive, we set up a prospective study to assess cerebrospinal fluid levels of interleukin-1beta, interleukin-6, interleukin-10, interleukin-12, soluble interleukin-2 receptor, interferon-gamma, tumor necrosis factor-alpha and neopterin in 20 patients with dementia of the Alzheimer type and 20 age- and sex-matched controls. Comparing both groups, no significant differences in concentrations and specific activities could be revealed. An additional 22 patients were included to enlarge the study population. No statistically significant differences were shown comparing patients (n=42) with the control group (n=20). We conclude that the immune-mediated inflammatory changes found in histopathological studies are not reflected in cerebrospinal fluid of patients with dementia of the Alzheimer type. Probably, cytokine production appears very localized in the central nervous system, not allowing representative detection in cerebrospinal fluid. Further studies assessing cytokine levels in various regions of central nervous system of patients with dementia of the Alzheimer type will be of interest to confirm this hypothesis.

Effects of microbial invasion on cerebral hemodynamics and oxygenation monitored by near infrared spectroscopy in experimental Escherichia coli meningitis in the newborn piglet

This study was carried out to elucidate the pathophysiologic mechanism of cerebral hyperemia observed during the early phase of bacterial meningitis. We tested the hypothesis that microbial invasion through the blood-brain barrier is responsible for cerebral vasodilation and hyperemia in meningitis. Escherichia coli was given either intravenously (i.v.) or intracisternally (i.c.) to closely mimic the primary or secondary bacterial invasion occurring in meningitis and newborn piglets were grouped according to their invasion results (+ or -); 12 in the i.v. (+) group, 14 in the i.v. (-) group, 13 in the i.c. (+) group, 15 in the i.c. (-) group. The results were compared with eight animals in the control group. Near infrared spectroscopy (NIRS) was employed to monitor changes in total hemoglobin (HbT), oxygenated hemoglobin (HbO), deoxygenated hemoglobin (Hb), deduced hemoglobin (HbD), and oxidized cytochrome aa3 (Cyt aa3). HbT, as an index of cerebral blood volume, increased progressively in both i.v. (+) and i.v. (-) groups and became significantly different from control and baseline values at 2 h. Hb significantly increased only in i.v. (+) group. HbD, as an index of cerebral blood flow, decreased significantly in i.v. (+), i.v.(-) and i.c. (-) groups and this change was mitigated in i.c. (+) group, HbO was reduced in i.c. (-) group and this decrease was attenuated in i.c. (+) group. Increased Cyt aa3 was observed in all experimental groups after bacterial inoculation. Changes in ICP, blood pressure, cerebral perfusion pressure, blood or CSF glucose or lactate, CSF TNF-alpha level, or CSF leukocytes number were not associated with changes in NIRS findings. These findings suggest that primary or secondary bacterial invasion across the blood-brain barrier is primarily responsible for cerebral vasodilation and hyperemia observed during the early phase of bacterial meningitis.

Efficacy of anti-tumor necrosis factor-alpha antibody as an adjunctive therapy in experimental Escherichia coli meningitis in the newborn piglet

This study was done to evaluate the efficacy of anti-tumor necrosis factor alpha (anti-TNF-alpha) antibody as an adjunctive therapy in neonatal bacterial meningitis. Newborn piglets were divided into three groups: 8 in the control group, 13 in the meningitis group (MG), and 10 in the meningitis with anti-TNF-alpha antibody group (AG). Meningitis was induced by intracisternal injection of 10(8) colony-forming units of Escherichia coli in 100 microl of saline. In the AG, 200 microl of anti-TNF-alpha antibody was also given intracisternally. In the AG, the elevated cerebrospinal fluid TNF-alpha level observed in the MG was completely abolished, and increased intracranial pressure, hypoglycorrhachia, and CSF pleocytosis observed in the MG were downmodulated. But blood, brain, and CSF lactate levels remained elevated in both MG and AG. Increased brain cell membrane lipid peroxidation products and decreased Na+,K+-ATPase activity observed in the MG were not attenuated in the AG. These results indicate that anti-TNF-alpha antibody was not particularly effective as an adjunctive therapy in attenuating acute inflammatory responses and ameliorating brain damage in neonatal bacterial meningitis.