Systemic and intrathecal immune activation in association with cerebral and cognitive outcomes in paediatric HIV.

Despite treatment, immune activation is thought to contribute to cerebral injury in children perinatally infected with human immunodeficiency virus (HIV). We aimed to characterize immune activation in relation to neuroimaging and cognitive outcomes. We therefore measured immunological, coagulation, and neuronal biomarkers in plasma and cerebrospinal fluid (CSF) samples of 34 perinatally HIV-infected children aged 8-18 years, and in plasma samples of 37 controls of comparable age, sex, ethnicity, and socio-economic status. We then compared plasma biomarker levels between groups, and explored associations between plasma/CSF biomarkers and neuroimaging and cognitive outcomes using network analysis. HIV-infected children showed higher plasma levels of C-reactive protein, interferon-gamma, interferon-gamma-inducible protein-10, and monocyte chemoattractant protein-1 than controls. In HIV-infected participants, plasma soluble CD14 was positively associated with microstructural white matter (WM) damage, and plasma D-dimer was negatively associated with WM blood flow. In CSF, IL-6 was negatively associated with WM volume, and neurofilament heavy-chain (NFH) was negatively associated with intelligence quotient and working memory. These markers of ongoing inflammation, immune activation, coagulation, and neuronal damage could be used to further evaluate the pathophysiology and clinical course of cerebral and cognitive deficits in perinatally acquired HIV.

The inflammatory marker GDF-15 is not independently associated with late-life depression.

OBJECTIVES: Growth differentiation factor-15 (GDF-15) is an inflammatory molecule that reacts to cell stress. Since major depression is associated with inflammation, we examined whether GDF-15 levels are elevated in patients with late-life depression. METHODS: Plasma GDF-15 levels were analyzed in 350 patients diagnosed with major depressive disorder in the last six months and 128 non-depressed controls from the Netherlands Study of Depression in Older persons (age ≥ 60 years). Major depressive disorder and age of onset were assessed with the Composite International Diagnostic Interview. Severity of depressive symptoms was measured with the Inventory of Depressive Symptoms (IDS-30). Multiple linear regression models were applied to study depression (diagnosis, onset age, severity, antidepressant drug use) as determinant of GDF-15 level, adjusted for demographic and clinical variables. RESULTS: Plasma GDF-15 levels were 22% higher in patients with major depression compared to controls. Within the depressed group, levels were higher in patients with older age of onset. GDF-15 levels showed a small, positive correlation to the levels of the inflammatory mediators IL-6 and C-reactive protein (r=0.23, and 0.24, p<0.05). This increase was independent from comorbidities, such as cardiovascular disease, rheumatism and diabetes, and anti-inflammatory drugs. However, this increase was dependent on lifestyle factors as smoking, physical activity and alcohol use. Within the depressed subgroup, neither depression severity or antidepressant drug use was associated with GDF-15 levels in the fully adjusted models. CONCLUSION: The inflammatory factor GDF-15 does not seem to be an independent inflammatory marker for late-life major depressive disorder.

BRI2 ectodomain affects Aß42 fibrillation and tau truncation in human neuroblastoma cells.

Alzheimer's disease (AD) is pathologically characterized by the presence of misfolded proteins such as amyloid beta (Aß) in senile plaques, and hyperphosphorylated tau and truncated tau in neurofibrillary tangles (NFT). The BRI2 protein inhibits Aß aggregation via its BRICHOS domain and regulates critical proteins involved in initiating the amyloid cascade, which has been hypothesized to be central in AD pathogenesis. We recently detected the deposition of BRI2 ectodomain associated with Aß plaques and concomitant changes in its processing enzymes in early stages of AD. Here, we aimed to investigate the effects of recombinant BRI2 ectodomain (rBRI276-266) on Aß aggregation and on important molecular pathways involved in early stages of AD, including the unfolded protein response (UPR), phosphorylation and truncation of tau, as well as apoptosis. We found that rBRI276-266 delays Aß fibril formation, although less efficiently than the BRI2 BRICHOS domain (BRI2 residues 113-231). In human neuroblastoma SH-SY5Y cells, rBRI276-266 slightly decreased cell viability and increased up to two-fold the Bax/Bcl-2 ratio and the subsequent activity of caspases 3 and 9, indicating activation of apoptosis. rBRI276-266 upregulated the chaperone BiP but did not modify the mRNA expression of other UPR markers (CHOP and Xbp-1). Strikingly, rBRI276-266 induced the activation of GSK3ß but not the phosphorylation of tau. However, exposure to rBRI276-266 significantly induced the truncation of tau, indicating that BRI2 ectodomain can contribute to NFT formation. Since BRI2 can also regulate the metabolism of Aß, the current data suggests that BRI2 ectodomain is a potential nexus between Aß, tau pathology and neurodegeneration.

Application of serum natalizumab levels during plasma exchange in MS patients with progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a severe complication of natalizumab treatment. Restoring immune function by plasmapheresis/immunoadsorption (PLEX/IA) is important for the outcome of PML. We report on four multiple sclerosis (MS) patients whom developed PML during natalizumab treatment, in whom we measured serum natalizumab concentrations before and during PLEX. Depending on the serum natalizumab concentration at the time of PML diagnosis, the number of PLEX treatments necessary to reach subtherapeutic serum natalizumab concentrations is variable. Measuring serum natalizumab concentrations before and during PLEX is helpful to determine the optimum number of PLEX treatments in individual MS patients with PML.

Brain-specific fatty acid-binding protein is elevated in serum of patients with dementia-related diseases.

BACKGROUND: There is a need for biomarkers in accessible matrices, such as blood, for the diagnosis of neurodegenerative diseases. The aim of this study was to measure the serum levels of brain-type fatty acid-binding protein (FABP) and heart-type FABP in patients with dementia-involving diseases. METHODS: Brain- and heart-type FABP were measured in serum samples from patients with either Alzheimer's disease (AD) (n = 31), Parkinson's disease (PD, n = 43), or other cognitive disorders (OCD, n = 42) and in 52 healthy controls. The localization of brain- and heart-type FABP was determined in brain sections by immunohistochemistry. RESULTS: Brain-type FABP levels were elevated in serum of 29%, 35%, and 24% of the patients with AD, PD, and OCD, respectively, and in 2% of the healthy donors. Heart-type FABP serum levels were not different amongst the patient groups. Brain-type and heart-type FABP expression was observed in reactive astrocytes in brain sections of patients with AD. CONCLUSIONS: In contrast to heart-type FABP, serum levels of brain-type FABP are elevated in a significant proportion of patients with various neurodegenerative diseases and can therefore have importance for defining subgroups of these patients.

EFNS guidelines on disease-specific CSF investigations.

We reviewed the literature for disease-specific markers in cerebrospinal fluid (CSF) and evaluated their diagnostic and prognostic relevance in neurological diseases. High tau protein in combination with low amyloid beta levels has a high sensitivity (80%) and specificity (90%) for Alzheimer's disease (AD) against normal aging and can predict conversion of mild cognitive impairment to AD. The detection of 14-3-3 has a high sensitivity (80-90%) and specificity (90%) for the diagnosis of CJD. Low or undetectable CSF hypocretin-1 (orexin-1) levels constitute a diagnostic biomarker for narcolepsy with cataplexy. Detection of beta-2-transferrin indicates CSF contamination in oto- and rhinorrhoe with a sensitivity of > 79% at a specificity of 95% similar to the beta-trace protein (sensitivity > 90%, specificity 100%). However, beta-trace protein is faster and cheaper to perform. Possible future biomarkers are: elevated levels of vascular endothelial growth factor are relatively sensitive (51-100%) and specific (73-100%) for leptomeningeal metastases from solid tumors and are associated with a poor prognosis in this condition. Elevated CSF neurofilament (Nf) levels probably reflect acute neuronal degeneration. The prognostic value of CSF Nf levels is highest in acute conditions such as subarachnoid hemorrhage, acute optic neuritis and neuromyelitis optica.

Immunological consequences of laparoscopic versus open transhiatal resection for malignancies of the distal esophagus and gastroesophageal junction.

BACKGROUND/AIM: Surgery remains the only curative therapy for esophageal cancer. The objective of the current study was to evaluate the impact of laparoscopic transhiatal esophagectomy versus open transhiatal esophagectomy on both inflammatory and immunological responses. METHODS: Seventeen patients undergoing laparoscopic or open surgery were included in the study. The postoperative inflammatory response was assessed by measuring WBC count and CRP, IL-6, IL-8, soluble TNF I and II receptor, and elastase levels. The postoperative immune function was assessed by measuring the monocyte HLA-DR expression. LPS-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI) were measured to evaluate bacterial translocation. RESULTS: The IL-6 level increased significantly more in the patients who received open surgery as compared with the laparoscopic group. Both LBP and BPI increased predominantly in the laparoscopic group as compared with the group who received open surgery. No difference was found in HLA-DR expression between the two groups. CONCLUSION: Although both laparoscopic and conventional esophageal resections result in an activation of the inflammatory response, this study suggests that this response could be less pronounced after the laparoscopic approach. However, in the laparoscopic group higher LBP and BPI levels were seen, suggesting an increased endotoxemia. We postulate that the persistently elevated abdominal pressure results in a loss of mucosal barrier function, resulting in bacterial translocation. The cellular acidification of the cells of the peritoneum induced by CO(2) insufflation, however, blunts the expected inflammatory response.

24S-hydroxycholesterol in relation to disease manifestations of acute experimental autoimmune encephalomyelitis.

Levels of the brain-specific cholesterol metabolite 24S-hydroxycholesterol are proposed as possible biomarkers for multiple sclerosis (MS). It is not yet clear for which aspect of the MS disease manifestations 24S-hydroxycholesterol is a reflection. We studied the relation of serum levels of 24S-hydroxycholesterol and other sterols to the disease characteristics of acute experimental autoimmune encephalomyelitis (EAE), an animal model for MS. Serum was analyzed for cholesterol precursors, oxysterols, and plant sterols during the course of disease development. Significantly increased levels of the cholesterol metabolites 24S-hydroxycholesterol and 27-hydroxycholesterol were observed on day 9, before the onset of clinical signs. The serum levels of these oxysterols gradually increased up to 193% and 415%, respectively, at day 17, when clinical symptoms had recovered. Total cholesterol levels were slightly but significantly decreased on day 9 and day 17 in treated animals. Serum levels of cholesterol precursors and plant sterols decreased gradually from day 11 and day 14, respectively. Immunostaining of the 24S-hydroxycholesterol-forming enzyme Cyp46 was shown in macrophage infiltrates. In vitro experiments confirmed the presence of Cyp46 in macrophages and showed a decreased expression after LPS treatment. The data indicate that changes in serum oxysterols occur early in EAE and can be formed by macrophages. These early changes indicate an important role for oxysterols in the development of EAE.

Growth-associated protein 43 in lesions and cerebrospinal fluid in multiple sclerosis.

Axonal damage in multiple sclerosis (MS) is correlated to disease progression. Early axonal damage may be compensated for by regenerative processes. Growth-associated protein 43 (GAP-43) is a marker for axonal growth and synaptogenesis in various neurodegenerative diseases. We investigated the expression of GAP-43 in 48 MS grey and white matter lesions of different stages. Decreased GAP-43 expression was found in 74% of the white matter lesions, independent of the lesion stage. In 19 out of 35 white matter lesions, areas of increased GAP-43 expression were present immediately adjacent to the lesions. Increased or unaltered expression was observed in remyelinated lesions. GAP-43 was expressed in neurofilament-positive structures. GAP-43 expression appeared unchanged in grey matter lesions. Macrophages were present in the areas of changed GAP-43 expression. cerebrospinal fluid GAP-43 levels were negatively correlated with magnetic resonance imaging measures of whole-brain atrophy (r = -0.30). In conclusion, these results indicate that decreased GAP-43 immunopositivity reflects axonal damage in MS lesions, which may again be reflected in decreased cerebrospinal fluid levels. The increased levels of GAP-43 in remyelinated or nondemyelinated white matter close to MS lesions may reflect regenerative attempts by damaged axons.

Antioxidants and polyunsaturated fatty acids in multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Oligodendrocyte damage and subsequent axonal demyelination is a hallmark of this disease. Different pathomechanisms, for example, immune-mediated inflammation, oxidative stress and excitotoxicity, are involved in the immunopathology of MS. The risk of developing MS is associated with increased dietary intake of saturated fatty acids. Polyunsaturated fatty acid (PUFA) and antioxidant deficiencies along with decreased cellular antioxidant defence mechanisms have been observed in MS patients. Furthermore, antioxidant and PUFA treatment in experimental allergic encephalomyelitis, an animal model of MS, decreased the clinical signs of disease. Low-molecular-weight antioxidants may support cellular antioxidant defences in various ways, including radical scavenging, interfering with gene transcription, protein expression, enzyme activity and by metal chelation. PUFAs may not only exert immunosuppressive actions through their incorporation in immune cells but also may affect cell function within the CNS. Both dietary antioxidants and PUFAs have the potential to diminish disease symptoms by targeting specific pathomechanisms and supporting recovery in MS.

Combination of serum markers related to several mechanisms in Alzheimer's disease.

Alzheimer's disease (AD) probably involves several pathobiochemical mechanisms and this may be reflected by changes in different serum components. The present study investigated whether the combined analysis of serum molecules related to different mechanisms improves the discrimination of AD patients from healthy controls. Serum of patients with AD was analyzed for a broad spectrum of marker molecules, including 11 inflammatory proteins, 12 sterol intermediates and phytosterols, 2 brain-specific proteins and 4 constituents involved in homocysteine homeostasis. The serum molecule concentrations were combined in a logistic regression model, using a forward stepwise inclusion mode. The results showed that the combination of interleukin-6 (IL-6) receptor, protein alpha1 fraction, cysteine and cholesterol concentrations improved the discrimination between AD patients and healthy controls compared to the single markers. In conclusion, the results of this study have shown that the complex pathology in AD is reflected in a pattern of altered serum concentrations of several marker molecules related to several pathobiochemical mechanisms.

Transport and metabolism of glutathione conjugates of menadione and ethacrynic acid in confluent monolayers of rat renal proximal tubular cells.

Confluent monolayers of primary rat renal proximal tubular (RPT) cells were used to compare transepithelial transport and concomitant metabolism of two different glutathione (GSH) S-conjugates. For the GSH-conjugated quinone compound, [35S]GSH-conjugated menadione (MGNQ), no specific transepithelial transport was observed. Most likely, [35S]MGNQ passed the monolayer via paracellular leakage as the result of a reduction in monolayer integrity due to toxicity via extensive redox cycling of the quinone under the culture conditions. RPT cell monolayers metabolise MGNQ into a cysteinylglycine conjugate, which after intramolecular cyclization yields 2H-(3-glycinyl)-9-hydroxy-10-methyl-1,4-naphthothiazine. Acivicin, an inhibitor of gamma-glutamyltranspeptidase, inhibited the formation of this 1,4-napthothiazine adduct. The second product formed is 1,4-napthothiazine formed by loss of glycine via the action of dipeptidases. Similarly, no basolateral (B) to apical (A) transport of a GSH-conjugated alpha, beta unsaturated ketone, [14C]ethacrynic acid (EASG), occurred. However, net transport of [14C] radioactivity could be observed from A=>B direction. After 8 h, 23% of total [14C] radioactivity was transported from the apical to the basolateral chamber. In both the apical and basolateral chambers, free, unconjugated ethacrynic acid (EA) was observed. gamma GT-mediated metabolism of EASG to the much more unstable cysteinylglycine conjugate leads to relatively large amounts of free EA. Thus, the GSH conjugate is not transported but rather the cysteine adduct and/or free, unconjugated EA. In agreement with this, acivicin reduced A=>B transport of EASG and inhibited the formation of free EA. In conclusion, the confluent monolayers of RPT cells do not or no longer possess active basolateral transport systems for GSH conjugates. However, they are still quite useful for studying biotransformation reactions of thioether conjugates.