Cardiovascular disease in Alpha 1 antitrypsin deficiency: an observational study assessing the role of neutrophil proteinase activity and the suitability of validated screening tools.

BACKGROUND: Alpha 1 Antitrypsin Deficiency (AATD) is a rare, inherited lung disease which shares features with Chronic Obstructive Pulmonary Disease (COPD) but has a greater burden of proteinase related tissue damage. These proteinases are associated with cardiovascular disease (CVD) in the general population. It is unclear whether patients with AATD have a greater risk of CVD compared to usual COPD, how best to screen for this, and whether neutrophil proteinases are implicated in AATD-associated CVD. This study had three aims. To compare CVD risk in never-augmented AATD patients to non-AATD COPD and healthy controls (HC). To assess relationships between CVD risk and lung physiology. To determine if neutrophil proteinase activity was associated with CVD risk in AATD. Cardiovascular risk was assessed by QRISK2® score and aortic stiffness measurements using carotid-femoral (aortic) pulse wave velocity (aPWV). Medical history, computed tomography scans and post-bronchodilator lung function parameters were reviewed. Systemic proteinase 3 activity was measured. Patients were followed for 4 years, to assess CVD development. RESULTS: 228 patients with AATD, 50 with non-AATD COPD and 51 healthy controls were recruited. In all COPD and HC participants, QRISK2® and aPWV gave concordant results (with both measures either high or in the normal range). This was not the case in AATD. Once aPWV was adjusted for age and smoking history, aPWV was highest and QRISK2® lowest in AATD patients compared to the COPD or HC participants. Higher aPWV was associated with impairments in lung physiology, the presence of emphysema on CT scan and proteinase 3 activity following adjustment for age, smoking status and traditional CVD risk factors (using QRISK2® scores) in AATD. There were no such relationships with QRISK2® in AATD. AATD patients with confirmed CVD at four-year follow up had a higher aPWV but not QRISK2® at baseline assessment. CONCLUSION: aPWV measured CVD risk is elevated in AATD. This risk is not captured by QRISK2®. There is a relationship between aPWV, lung disease and proteinase-3 activity. Proteinase-driven breakdown of elastin fibres in large arteries and lungs is a putative mechanism and forms a potential therapeutic target for CVD in AATD.

Survival following lung volume reduction procedures: results from the UK Lung Volume Reduction (UKLVR) registry.

INTRODUCTION: Lung volume reduction surgery (LVRS) and endobronchial valve (EBV) placement can produce substantial benefits in appropriately selected people with emphysema. The UK Lung Volume Reduction (UKLVR) registry is a national multicentre observational study set up to support quality standards and assess outcomes from LVR procedures at specialist centres across the UK. METHODS: Data were analysed for all patients undergoing an LVR procedure (LVRS/EBV) who were recruited into the study at participating centres between January 2017 and June 2022, including; disease severity and risk assessment, compliance with guidelines for selection, procedural complications and survival to February 2023. RESULTS: Data on 541 patients from 14 participating centres were analysed. Baseline disease severity was similar in patients who had surgery n=244 (44.9%), or EBV placement n=219 (40.9%), for example, forced expiratory volume in 1 s (FEV1) 32.1 (12.1)% vs 31.2 (11.6)%. 89% of cases had discussion at a multidisciplinary meeting recorded. Median (IQR) length of stay postprocedure for LVRS and EBVs was 12 (13) vs 4 (4) days(p=0.01). Increasing age, male gender and lower FEV1%predicted were associated with mortality risk, but survival did not differ between the two procedures, with 50 (10.8%) deaths during follow-up in the LVRS group vs 45 (9.7%) following EBVs (adjusted HR 1.10 (95% CI 0.72 to 1.67) p=0.661) CONCLUSION: Based on data entered in the UKLVR registry, LVRS and EBV procedures for emphysema are being performed in people with similar disease severity and long-term survival is similar in both groups.

Incidence of depression and antidepressant prescription in patients with COPD: A large UK population-based cohort study.

BACKGROUND: Depression is frequently reported in patients with Chronic Obstructive Pulmonary Disease (COPD). However, there is little information available on the incidence of depression following a COPD diagnosis. OBJECTIVE: To determine the incidence of a new diagnosis of depression or antidepressant prescription in people with and without a COPD diagnosis. METHODS: A matched cohort study was conducted using The Health Improvement Network database. Patients with confirmed COPD diagnosis were matched to up to four subjects without a COPD diagnosis by age, sex and GP practice. Cox proportional hazards models were used to assess the incidence rates of depression and antidepressant prescription. RESULTS: 44,362 patients with COPD and 124,140 subjects without COPD were included. The incidence rate of depression per 1000 person-years following COPD diagnosis was greater (11.4; 95% CI: 10.9-11.8) compared to subjects without COPD (5.7; 95% CI: 5.5-5.8) (p < 0.001). Patients with COPD were 42% more likely to have an incident depression (adjusted hazard ratio [aHR]: 1.42; 95% CI: 1.32-1.53; p < 0.001), and 40% more likely to be prescribed an antidepressant (aHR: 1.40; 95% CI: 1.35-1.45; p < 0.001). The incidence to either depression or antidepressant prescription was also greater for patients with COPD (aHR: 1.41; 95% CI: 1.36-1.46; p < 0.001). Patients with COPD and worse breathlessness had a higher risk of incident depression compared to patients with less breathlessness. CONCLUSION: Healthcare providers managing patients with COPD should be alert to the existence of depression and aware of its symptoms and consequences.

Risk of incident dementia and cognitive impairment in patients with chronic obstructive pulmonary disease (COPD): A large UK population-based study.

BACKGROUND: Although cognitive impairment and dementia are common comorbidities in patients with chronic obstructive pulmonary disease (COPD), estimates of incidence following a diagnosis of COPD are inconclusive. OBJECTIVE: To determine the incidence of cognitive impairment and dementia in people with and without a COPD diagnosis. METHODS: A population-based study using UK General Practice (GP) health records from The Health Improvement Network database was conducted. Patients with confirmed COPD diagnosis, ≥40 years old, were matched to up to four subjects without a COPD diagnosis by age, sex and GP practice. Cox proportional hazards models were used to assess the incidence rates of cognitive impairment and dementia. RESULTS: Of patients with COPD (n = 62,148), 9% developed cognitive impairment, compared with 7% of subjects without COPD (n = 230,076), p < 0.001. The incidence of cognitive impairment following COPD diagnosis was greater than in subjects without COPD following index date (adjusted Hazard Ratio (aHR), 1.21; 95% CI: 1.16 ─ 1.26, p < 0.001). The coded incidence of either cognitive impairment or dementia was also greater in patients with COPD following adjustment for confounders (aHR: 1.13, 95% CI: 1.09 ─ 1.18, p < 0.001). Coded incident dementia alone was not different between patients with COPD and subjects without COPD (aHR, 0.91, 95% CI: 0.83 ─ 1.01, p = 0.053). CONCLUSION: Despite the increased incidence of cognitive impairment in patients with COPD, incidence of dementia was not as frequently recorded in patients with COPD. This raises the concern of undiagnosed dementia and emphasises the need for a systematic assessment in this population.

Notch Coordinates Periodontal Ligament Maturation through Regulating Lamin A.

Tooth eruption is a continuous biological process with dynamic changes at cellular and tissue levels, particularly within the periodontal ligament (PDL). Occlusion completion is a significant physiological landmark of dentition establishment. However, the importance of the involvement of molecular networks engaging in occlusion establishment on the final PDL maturation is still largely unknown. In this study, using rat and mouse molar teeth and a human PDL cell line for RNAseq and proteomic analysis, we systematically screened the key molecular links in regulating PDL maturation before and after occlusion establishment. We discovered Notch, a key molecular pathway in regulating stem cell fate and differentiation, is a major player in the event. Intercepting the Notch pathway by deleting its key canonical transcriptional factor, RBP-Jkappa, using a conditional knockout strategy in the mice delayed PDL maturation. We also identified that Lamin A, a cell nuclear lamina member, is a unique marker of PDL maturation, and its expression is under the control of Notch signaling. Our study therefore provides a deep insight of how PDL maturation is regulated at the molecular level, and we expect the outcomes to be applied for a better understanding of the molecular regulation networks in physiological conditions such as tooth eruption and movement and also for periodontal diseases.

Levels of circulating MMP-7 degraded elastin are elevated in pulmonary disorders.

OBJECTIVES: Elastin is a signature protein of the lungs. Matrix metalloproteinase-7 (MMP-7) is important in lung defence mechanisms and degrades elastin. However, MMP-7 activity in regard to elastin degradation has never been quantified serologically in patients with lung diseases. An assay for the quantification of MMP-7 generated elastin fragments (ELM7) was therefore developed to investigate MMP-7 derived elastin degradation in pulmonary disorders such as idiopathic pulmonary fibrosis (IPF) and lung cancer. DESIGN AND METHODS: Monoclonal antibodies (mABs) were raised against eight carefully selected MMP-7 cleavage sites on elastin. After characterisation and validation of the mABs, one mAB targeting the ELM7 fragment was chosen. ELM7 fragment levels were assessed in serum samples from patients diagnosed with IPF (n=123, baseline samples, CTgov reg. NCT00786201), and lung cancer (n=40) and compared with age- and sex-matched controls. RESULTS: The ELM7 assay was specific towards in vitro MMP-7 degraded elastin and the ELM7 neoepitope but not towards other MMP-7 derived elastin fragments. Serum ELM7 levels were significantly increased in IPF (113%, p<0.0001) and lung cancer (96%, p<0.0001) compared to matched controls. CONCLUSIONS: MMP-7-generated elastin fragments can be quantified in serum and may reflect pathological lung tissue turnover in several important lung diseases.

Chronic disease influences over 40 major life-changing decisions (MLCDs): a qualitative study in dermatology and general medicine.

BACKGROUND: Chronic disease not only impairs patients' psycho-social well-being but also influences major life-changing decisions (MLCDs). There is little information about the types of MLCDs affected and the long-term consequences. OBJECTIVES: The aims were to identify the MLCDs influenced by chronic disease, to define 'MLCD' and to suggest support strategies for patients taking MLCDs. METHODS: Adult dermatology patients explained how their chronic disease had influenced MLCDs in individual interviews. Adult patients from other medical specialities gave similar information by postal survey. NVivo8 software was used for qualitative analysis of data. Themes were categorized through a coding-recoding iterative process. RESULTS: There were 308 evaluable responses (male 55.2%; mean age = 51.8 years, mean disease duration = 19 years) from the 365 (55.7%) responses to the 655 patient invitations. These were used to generate themes to conceptualize 'MLCDs'. The most frequently reported MLCDs in the dermatology interviews concerned career choice (66%), job (58%), choice of clothing (54%), relationships (52%), education (44%), stopping swimming (34%), moving abroad (32%), not socializing (34%), wearing make-up (22%) and having children (22%). In the postal survey early retirement (40.6%), impact on job (29.4%), having children (24.8%), career choice (22.4%) and relationships (15.5%) were most commonly reported. The number of MLCDs reported by individuals was inversely related to age. Forty-one affected MLCD themes were grouped into 18 MLCD categories. A definition of MLCD was developed and strategies suggested to support patients. CONCLUSIONS: Chronic diseases influence a wide range of MLCDs. MLCDs are a novel domain in disease burden assessment. Clinicians' knowledge about this is important in patient management.

Evaluation of the Effects of Sativex (THC BDS: CBD BDS) on Inhibition of Spasticity in a Chronic Relapsing Experimental Allergic Autoimmune Encephalomyelitis: A Model of Multiple Sclerosis.

This study investigated the antispasticity potential of Sativex in mice. Chronic relapsing experimental allergic encephalomyelitis was induced in adult ABH mice resulting in hind limb spasticity development. Vehicle, Sativex, and baclofen (as a positive control) were injected intravenously and the "stiffness" of limbs assessed by the resistance force against hind limb flexion. Vehicle alone caused no significant change in spasticity. Baclofen (5 mg/kg) induced approximately a 40% peak reduction in spasticity. Sativex dose dependently reduced spasticity; 5 mg/kg THC + 5 mg/kg CBD induced approximately a 20% peak reduction; 10 mg/kg THC + 10 mg/kg CBD produced approximately a 40% peak reduction in spasticity. Sativex has the potential to reduce spasticity in an experimental mouse model of multiple sclerosis (MS). Baclofen reduced spasticity and served as a positive control. Sativex (10 mg/kg) was just as effective as baclofen, providing supportive evidence for Sativex use in the treatment of spasticity in MS.

Increased augmentation index in patients with cystic fibrosis.

Increased large artery stiffness occurs in a range of inflammatory conditions indicating an ageing of the vasculature and additionally being an independent risk factor for cardiovascular events. We determined large artery parameters in adults with cystic fibrosis (CF). 50 clinically stable adult patients with CF (mean+/-sd age 28.0+/-8.2 yrs) and 26 controls matched for age, sex and body mass index were studied. Central aortic blood pressure, augmentation index (AIx) and aortic pulse wave velocity (PWV) were determined using applanation tonometry. Lung function, diabetic status and C-reactive protein (CRP) were also determined. Mean+/-sd AIx was greater in patients than controls, 8.5+/-11.1% and -1.8+/-13.1%, respectively (p<0.001), while PWV was similar. Although AIx was greatest in the sub-group with CF-related diabetes (CFRD), it was also increased in the non-CFRD sub-group when compared with controls. In patients, AIx was related to log(10) CRP (r = 0.33) and forced vital capacity (r = -0.34; both p<0.05), and CRP remained predictive in multiple regression. AIx is increased in adults with CF, in the presence of a normal blood pressure and independent of diabetic status. AIx was related to the systemic inflammatory status. These findings have implications for management and require further exploration so that cardiovascular health can be maintained.

Circulating matrix metalloproteinase-9 and osteoporosis in patients with chronic obstructive pulmonary disease.

Matrix metalloproteinase-9 (MMP-9) has been implicated in airways injury in chronic obstructive pulmonary disease (COPD). Osteoporosis is common in patients with COPD, and MMP-9 is an indicator of activated osteoclasts. We hypothesized that circulating MMP-9 would be related to bone mineral density (BMD) in COPD. We explored the relationship between MMP-9, tissue inhibitors of metalloproteinases (TIMP)-1 and -2, and BMD status in patients with COPD. A total of 70 clinically stable patients with confirmed COPD and 39 control subjects underwent spirometry, dual-energy x-ray absorptiometry to determine BMD, and venous sampling for measurement of cytokines and MMP-9 and TIMP-1 and -2. In patients, circulating MMP-9 was increased: mean (SD) 38.5 (2.2) compared with control subjects 20.1 (2.0) ng/mL, P < 0.001, whereas TIMP-1 and -2 were not different. In the patients, MMP-9 was greater in those with osteoporosis, compared with those with osteopenia, no bone disease or control subjects, and patients with osteopenia had greater MMP-9 than control subjects. The adjusted receiver operating characteristics curve area for MMP-9 detecting osteoporosis was 0.86. Patients had elevated systemic inflammatory mediators compared with control subjects, but these were unrelated to bone status. Increased circulating MMP-9 in patients with COPD was related to the presence of osteoporosis and not to lung function. MMP-9 may be a biomarker of increased bone resorption.

The discovery of critical illness polyneuropathy.

In 1892 Osler described 'rapid loss of flesh' in prolonged sepsis. Thereafter, for years, limb weakness was attributed to cachectic myopathy, and difficulty weaning from mechanical ventilation was attributed to diaphragmatic fatigue. In 1961 Mertens described 'coma-polyneuropathies', and in 1971 Henderson and colleagues described polyneuropathy in patients with burns. In 1984 Bolton and colleagues, in a series of reports, defined the clinical, electrophysiological and morphological features of septic encephalopathy and critical illness polyneuropathy. Evidence suggested that polyneuropathy was due to the 'toxic' effects of sepsis. Polyneuropathy was a common cause of difficulty in weaning when lung and cardiac cause had been excluded. Since 1984, cases of critical illness polyneuropathy have been reported from several countries. Moreover, a number of investigators reported instances of critical illness myopathy. Comprehensive studies by Latronico and colleagues indicated that polyneuropathy and myopathy often occurred together in the same patient. With successful treatment of sepsis, improvement often occurred in encephalopathy, polyneuropathy and myopathy, except in very severe cases.

What community measurements can be used to predict bone disease in patients with COPD?

BACKGROUND: Osteoporosis is common in patients with COPD. Previously we have reported that loss of fat-free mass (FFM), measured by dual X-ray absorptiometry (DXA) is associated with loss of bone mineral density (BMD). In addition, in patients with a low body mass index (BMI) and a low FFM, all had evidence of bone thinning, 50% having osteopenia and 50% osteoporosis. We explored the utility of different anthropometric measures in detecting osteoporosis in a community-based COPD population. METHODS: Patients with confirmed COPD and not on long-term oral corticosteroids (n=58) performed spirometry. They underwent nutritional assessment by skinfold anthropometry, midarm circumference, calculation of both % ideal body weight (IBW) and BMI. All had DXA assessment of BMD. RESULTS: A total of 58 COPD patients had anthropometric measurements taken, with a mean age of 66.8 (SD 8.7) years, 31 (58%) were male, with a forced expiratory volume in 1s (FEV(1)) of 54.17 (20.18)% predicted. Osteoporosis was present at either the hip or lumbar region in 14 patients (24%). The useful anthropometric measurements identifying those with osteoporosis were both % IBW and BMI. The adjusted odds ratio for %IBW was 0.93 (95% confidence interval (CI) 0.87, 0.99), p=0.016 and for BMI: 0.79 (0.64-0.98), p=0.03. The receiver operating characteristics (ROC) score for both was 0.88, indicating a good fit. CONCLUSION: Osteoporosis is common, even in patients with mild airways obstruction. Nutritional assessment, incorporating a calculation of their BMI or %IBW may confer an additional benefit in detecting those at risk of osteoporosis and guide referral for BMD measurement.

The translation of drug efficacy from in vivo models to human disease with special reference to experimental autoimmune encephalomyelitis and multiple sclerosis.

The search for new drugs to treat human disease is strongly reliant on the use of in vivo animal models to generate pre-clinical data. However, drug efficacy in experimental disease models does not often translate effectively to the human condition. Multiple sclerosis (MS) is a disease of the human central nervous system that has features duplicated in the animal model experimental autoimmune encephalomyelitis (EAE). Many compounds have shown activity in EAE and some have progressed to clinical trials in MS but only a small number of treatments have proved beneficial. This article describes compounds with dual activity in EAE and MS and considers the possible reasons for transference of drug effects from the model to the human disease. Prerequisites to ensure robust pharmacological efficacy in EAE are discussed with the aim of improving the success rate for pre-clinically active compounds being of benefit in the treatment of MS.

Randomized, double-blind study comparing the efficacy of moderate-dose metoclopramide and ondansetron for the prophylactic control of postoperative vomiting in children after tonsillectomy.

BACKGROUND: Postoperative vomiting (POV) is a major cause of morbidity after tonsillectomy in children. It has been well established that anti-serotinergic agents are effective for the prophylactic control of POV in this patient group. It has been suggested that at moderate doses (0.5 mg kg(-1)), metoclopramide is also an effective agent. No study has been performed comparing the efficacy of an anti-serotinergic agent and moderate-dose metoclopramide. METHODS: A total of 557 children undergoing tonsillectomy with or without adenoidectomy were randomly allocated to receive either ondansetron 0.1 mg kg(-1) or metoclopramide 0.5 mg kg(-1). All received a standardized muscle-relaxant anaesthetic and dexamethasone 0.1 mg kg(-1). The primary outcome was any vomit in the immediate postoperative period. Comparisons were made of the proportion in each group reaching the primary outcome and the time until their first vomit. The study was designed to detect equivalence. RESULTS: The incidence of vomiting in the group receiving ondansetron (25.3%) was 12% lower (95% CI 4.4-19.7) than those in metoclopramide (37.3%). The time until first vomit was significantly longer in the group receiving ondansetron (hazard ratio 0.61, 95% CI 0.45-0.82). CONCLUSIONS: Although the incidence of vomiting was similar, when these results are compared with a pre-specified zone of equivalence of 0-15%, it cannot be concluded that the effect of metoclopramide is equivalent to ondansetron. Survival analysis indicated that those in the metoclopramide group vomited substantially earlier. It is concluded, therefore, that ondansetron 0.1 mg kg(-1) is a superior drug to metoclopramide 0.5 mg kg(-1) for the prophylactic control of POV in children undergoing tonsillectomy.

Insulin resistance and inflammation - A further systemic complication of COPD.

Chronic obstructive pulmonary disease (COPD) is associated with a continuous systemic inflammatory response. Furthermore, COPD is associated with an excess risk for cardiovascular disease and type II diabetes. Systemic inflammation in other populations is a factor in atherogenesis and has been associated with insulin resistance. We assessed the association between systemic inflammation and insulin resistance in non-hypoxaemic patients with COPD. Fasting plasma glucose, insulin and inflammatory mediators were measured in 56 patients and 29 healthy subjects. Body mass index (BMI) and height squared fat- and fat-free-mass index were similar between subject groups. Using homeostatic modelling techniques, mean (SD) insulin resistance was greater in the patients, 1.68 (2.58) and 1.13 (2.02) in healthy subjects, p=0.032. Fasting plasma insulin was increased in patients while glucose was similar to that in healthy subjects. Patients had increased circulating inflammatory mediators. Insulin resistance was related to interleukin-6 (IL-6), r=0.276, p=0.039, and tumour necrosis factor alpha soluble receptor I, r=0.351, p=0.008. Both IL-6 and BMI were predictive variables of insulin resistance r(2)=0.288, p<0.05. We demonstrated greater insulin resistance in non-hypoxaemic patients with COPD compared with healthy subjects, which was related to systemic inflammation. This relationship may indicate a contributory factor in the excess risk of cardiovascular disease and type II diabetes in COPD.

Interventions for helping people recognise early signs of recurrence in bipolar disorder.

BACKGROUND: Recurrence rates for bipolar disorder are high despite effective treatments with mood stabiliser drugs. Self-help treatments and psychological treatments that teach patients to recognise and manage early warning symptoms and signs (EWS) of impending manic or depressive episodes are popular with patients. The main aim of such interventions is to intervene early and prevent bipolar episodes, thereby increasing the time to the next recurrence and preventing hospitalisation. OBJECTIVES: To compare the effectiveness of an EWS intervention plus treatment as usual (TAU ) versus TAU (involving and not involving a psychological therapy) on time to manic, depressive and all bipolar episodes (the primary outcome), hospitalisation, functioning, depressive and manic symptoms. SEARCH STRATEGY: Relevant studies identified by searching Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Registers (CCDANCTR-Studies and CCDANCTR-References - searched on 20/10/2005), supplemented with hand searching the journal Bipolar Disorders, searching the UK National Research Register, checking reference lists of included studies and contacting authors. SELECTION CRITERIA: Only randomised controlled trials (RCTs) were included. Participants were adults with a diagnosis of bipolar disorder based on standardised psychiatric criteria. DATA COLLECTION AND ANALYSIS: Two reviewers independently rated trials for inclusion. Data were extracted from included trials by reviewers using a data extraction sheet. Authors of all the included studies were contacted for any additional information required. Time to recurrence data was summarised as log hazard ratios, dichotomous data as relative risk and continuous data as weighted mean difference, using random effects models to calculate effect size only when there was heterogeneity in the data. MAIN RESULTS: Eleven RCTs were identified, but only six provided primary outcome data. All six RCTs were of high quality. Time to first recurrence of any type (RE, hazards ratio 0.57, 95% CI 0.39 to 0.82), time to manic/hypomanic episode, time to depressive episode, and percentage of people hospitalised and functioning favoured the intervention group. Neither depressive nor hypomanic symptoms differed between intervention and control groups. AUTHORS' CONCLUSIONS: This review shows a beneficial effect of EWS in time to recurrence, percentage of people hospitalised and functioning in people with bipolar disorder. However, the absence of data on the primary outcome measure in so many included studies is a source of concern and a potential source of bias. Mental health services should consider routinely providing EWS interventions to adults with bipolar disorder, as they appear to reduce hospitalisation and therefore may be cost-effective.

Glutamate-stimulated peroxynitrite production in a brain-derived endothelial cell line is dependent on N-methyl-D-aspartate (NMDA) receptor activation.

There is accumulating and convincing evidence indicating a role for glutamate in the pathogenesis of the human demyelinating disease multiple sclerosis (MS). Studies in experimental autoimmune encephalomyelitis (EAE), the animal model of MS, demonstrate that pharmacological inhibition of specific glutamate receptors suppresses neurological symptoms and prevents blood-brain barrier (BBB) breakdown. The mechanisms through which glutamate influences BBB function during EAE remain unclear. Glutamate triggers the production of nitric oxide and superoxide, which can lead to the formation of peroxynitrite (ONOO(-)). Recent studies have implicated ONOO(-) in the loss of neurovascular integrity during EAE. We propose that glutamate contributes to BBB breakdown via the actions of ONOO(-). The present investigation examined glutamate-induced ONOO(-) formation in the b.End3 brain-derived endothelial cell line. b.End3 cells were incubated with a concentration range of glutamate and ONOO(-) production was assessed over time. Results showed a concentration- and time-dependent increase in ONOO(-) levels in glutamate-treated cells that were suppressed by selective and non-selective inhibitors of ONOO(-)-mediated reactions. Specific activation of b.End3-associated NMDA receptors also resulted in a concentration-dependent increase in ONOO(-) production. The ability of b.End3 cells to respond to the presence of glutamate was confirmed through the detection of NMDA receptor immnuoreactivity in cell extracts. In addition, the use of the NMDA receptor antagonists MK-801 and memantine reduced glutamate-mediated ONOO(-) generation from b.End3 cells. The data reinforce the important relationship between glutamate and the NMDA receptor, positioned at neurovascular sites, which may be of particular relevance to the pathogenesis of demyelinating disease.