Changes in hospital mortality in patients with cancer during the COVID-19 pandemic (ISARIC-CCP-UK): a prospective, multicentre cohort study

BACKGROUND

Patients with cancer are at greater risk of dying from COVID-19 than many other patient groups. However, how this risk evolved during the pandemic remains unclear. We aimed to determine, on the basis of the UK national pandemic protocol, how factors influencing hospital mortality from COVID-19 could differentially affect patients undergoing cancer treatment. We also examined changes in hospital mortality and escalation of care in patients on cancer treatment during the first 2 years of the COVID-19 pandemic in the UK.

METHODS

We conducted a prospective cohort study of patients aged older than 19 years and admitted to 306 health-care facilities in the UK with confirmed SARS-CoV-2 infection, who were enrolled in the International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) WHO Clinical Characterisation Protocol (CCP) across the UK from April 23, 2020, to Feb 28, 2022; this analysis included all patients in the complete dataset when the study closed. The primary outcome was 30-day in-hospital mortality, comparing patients on cancer treatment and those without cancer. The study was approved by the South Central-Oxford C Research Ethics Committee in England (Ref: 13/SC/0149) and the Scotland A Research Ethics Committee (Ref 20/SS/0028), and is registered on the ISRCTN Registry (ISRCTN66726260).

FINDINGS

177 871 eligible adult patients either with no history of cancer (n=171 303) or on cancer treatment (n=6568) were enrolled; 93 205 (52·4%) were male, 84 418 (47·5%) were female, and in 248 (13·9%) sex or gender details were not specified or data were missing. Patients were followed up for a median of 13 (IQR 6-21) days. Of the 6568 patients receiving cancer treatment, 2080 (31·7%) died at 30 days, compared with 30 901 (18·0%) of 171 303 patients without cancer. Patients aged younger than 50 years on cancer treatment had the highest age-adjusted relative risk (hazard ratio [HR] 5·2 [95% CI 4·0-6·6], p<0·0001; vs 50-69 years 2·4 [2·2-2·6], p<0·0001; 70-79 years 1·8 [1·6-2·0], p<0·0001; and >80 years 1·5 [1·3-1·6], p<0·0001) but a lower absolute risk (51 [6·7%] of 763 patients <50 years died compared with 459 [30·2%] of 1522 patients aged >80 years). In-hospital mortality decreased for all patients during the pandemic but was higher for patients on cancer treatment than for those without cancer throughout the study period.

INTERPRETATION

People with cancer have a higher risk of mortality from COVID-19 than those without cancer. Patients younger than 50 years with cancer treatment have the highest relative risk of death. Continued action is needed to mitigate the poor outcomes in patients with cancer, such as through optimising vaccination, long-acting passive immunisation, and early access to therapeutics. These findings underscore the importance of the ISARIC-WHO pandemic preparedness initiative.

FUNDING

National Institute for Health Research and the Medical Research Council.

Patient emergency health-care use before hospital admission for COVID-19 and long-term outcomes in Scotland: a national cohort study

BACKGROUND

It is unclear what effect the pattern of health-care use before admission to hospital with COVID-19 (index admission) has on the long-term outcomes for patients. We sought to describe mortality and emergency readmission to hospital after discharge following the index admission (index discharge), and to assess associations between these outcomes and patterns of health-care use before such admissions.

METHODS

We did a national, retrospective, complete cohort study by extracting data from several national databases and linking the databases for all adult patients admitted to hospital in Scotland with COVID-19. We used latent class trajectory modelling to identify distinct clusters of patients on the basis of their emergency admissions to hospital in the 2 years before the index admission. The primary outcomes were mortality and emergency readmission up to 1 year after index admission. We used multivariable regression models to explore associations between these outcomes and patient demographics, vaccination status, level of care received in hospital, and previous emergency hospital use.

FINDINGS

Between March 1, 2020, and Oct 25, 2021, 33 580 patients were admitted to hospital with COVID-19 in Scotland. Overall, the Kaplan-Meier estimate of mortality within 1 year of index admission was 29·6% (95% CI 29·1-30·2). The cumulative incidence of emergency hospital readmission within 30 days of index discharge was 14·4% (95% CI 14·0-14·8), with the number increasing to 35·6% (34·9-36·3) patients at 1 year. Among the 33 580 patients, we identified four distinct patterns of previous emergency hospital use: no admissions (n=18 772 [55·9%]); minimal admissions (n=12 057 [35·9%]); recently high admissions (n=1931 [5·8%]), and persistently high admissions (n=820 [2·4%]). Patients with recently or persistently high admissions were older, more multimorbid, and more likely to have hospital-acquired COVID-19 than patients with no or minimal admissions. People in the minimal, recently high, and persistently high admissions groups had an increased risk of mortality and hospital readmission compared with those in the no admissions group. Compared with the no admissions group, mortality was highest in the recently high admissions group (post-hospital mortality HR 2·70 [95% CI 2·35-2·81]; p<0·0001) and the risk of readmission was highest in the persistently high admissions group (3·23 [2·89-3·61]; p<0·0001).

INTERPRETATION

Long-term mortality and readmission rates for patients hospitalised with COVID-19 were high; within 1 year, one in three patients had died and a third had been readmitted as an emergency. Patterns of hospital use before index admission were strongly predictive of mortality and readmission risk, independent of age, pre-existing comorbidities, and COVID-19 vaccination status. This increasingly precise identification of individuals at high risk of poor outcomes from COVID-19 will enable targeted support.

FUNDING

Chief Scientist Office Scotland, UK National Institute for Health Research, and UK Research and Innovation.

Prospective validation of the 4C prognostic models for adults hospitalised with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol

PURPOSE

To prospectively validate two risk scores to predict mortality (4C Mortality) and in-hospital deterioration (4C Deterioration) among adults hospitalised with COVID-19.

METHODS

Prospective observational cohort study of adults (age ≥18 years) with confirmed or highly suspected COVID-19 recruited into the International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) WHO Clinical Characterisation Protocol UK (CCP-UK) study in 306 hospitals across England, Scotland and Wales. Patients were recruited between 27 August 2020 and 17 February 2021, with at least 4 weeks follow-up before final data extraction. The main outcome measures were discrimination and calibration of models for in-hospital deterioration (defined as any requirement of ventilatory support or critical care, or death) and mortality, incorporating predefined subgroups.

RESULTS

76 588 participants were included, of whom 27 352 (37.4%) deteriorated and 12 581 (17.4%) died. Both the 4C Mortality (0.78 (0.77 to 0.78)) and 4C Deterioration scores (pooled C-statistic 0.76 (95% CI 0.75 to 0.77)) demonstrated consistent discrimination across all nine National Health Service regions, with similar performance metrics to the original validation cohorts. Calibration remained stable (4C Mortality: pooled slope 1.09, pooled calibration-in-the-large 0.12; 4C Deterioration: 1.00, -0.04), with no need for temporal recalibration during the second UK pandemic wave of hospital admissions.

CONCLUSION

Both 4C risk stratification models demonstrate consistent performance to predict clinical deterioration and mortality in a large prospective second wave validation cohort of UK patients. Despite recent advances in the treatment and management of adults hospitalised with COVID-19, both scores can continue to inform clinical decision making.

TRIAL REGISTRATION NUMBER

ISRCTN66726260.

Genome-wide analysis identifies gallstone-susceptibility loci including genes regulating gastrointestinal motility

BACKGROUND AND AIMS

Genome-wide association studies (GWAS) have identified several risk loci for gallstone disease. As with most polygenic traits, it is likely that many genetic determinants are undiscovered. The aim of this study was to identify genetic variants that represent new targets for gallstone research and treatment.

APPROACH AND RESULTS

We performed a GWAS of 28,627 gallstone cases and 348,373 controls in the UK Biobank, replicated findings in a Scottish cohort (1089 cases, 5228 controls), and conducted a GWA meta-analysis (43,639 cases, 506,798 controls) with the FinnGen cohort. We assessed pathway enrichment using gene-based then gene-set analysis and tissue expression of identified genes in Genotype-Tissue Expression project data. We constructed a polygenic risk score (PRS) and evaluated phenotypic traits associated with the score. Seventy-five risk loci were identified (p < 5 × 10-8 ), of which 46 were new. Pathway enrichment revealed associations with lipid homeostasis, glucuronidation, phospholipid metabolism, and gastrointestinal motility. Anoctamin 1 (ANO1) and transmembrane Protein 147 (TMEM147), both in novel, replicated loci, are expressed in the gallbladder and gastrointestinal tract. Both regulate gastrointestinal motility. The gallstone risk allele rs7599-A leads to suppression of hepatic TMEM147 expression, suggesting that the protein protects against gallstone formation. The highest decile of the PRS demonstrated a 6-fold increased odds of gallstones compared with the lowest decile. The PRS was strongly associated with increased body mass index, serum liver enzymes, and C-reactive protein concentrations, and decreased lipoprotein cholesterol concentrations.

CONCLUSIONS

This GWAS demonstrates the polygenic nature of gallstone risk and identifies 46 novel susceptibility loci. We implicate genes influencing gastrointestinal motility in the pathogenesis of gallstones.

Implementation of corticosteroids in treatment of COVID-19 in the ISARIC WHO Clinical Characterisation Protocol UK: prospective, cohort study

BACKGROUND

Dexamethasone was the first intervention proven to reduce mortality in patients with COVID-19 being treated in hospital. We aimed to evaluate the adoption of corticosteroids in the treatment of COVID-19 in the UK after the RECOVERY trial publication on June 16, 2020, and to identify discrepancies in care.

METHODS

We did an audit of clinical implementation of corticosteroids in a prospective, observational, cohort study in 237 UK acute care hospitals between March 16, 2020, and April 14, 2021, restricted to patients aged 18 years or older with proven or high likelihood of COVID-19, who received supplementary oxygen. The primary outcome was administration of dexamethasone, prednisolone, hydrocortisone, or methylprednisolone. This study is registered with ISRCTN, ISRCTN66726260.

FINDINGS

Between June 17, 2020, and April 14, 2021, 47 795 (75·2%) of 63 525 of patients on supplementary oxygen received corticosteroids, higher among patients requiring critical care than in those who received ward care (11 185 [86·6%] of 12 909 vs 36 415 [72·4%] of 50 278). Patients 50 years or older were significantly less likely to receive corticosteroids than those younger than 50 years (adjusted odds ratio 0·79 [95% CI 0·70-0·89], p=0·0001, for 70-79 years; 0·52 [0·46-0·58], p<0·0001, for >80 years), independent of patient demographics and illness severity. 84 (54·2%) of 155 pregnant women received corticosteroids. Rates of corticosteroid administration increased from 27·5% in the week before June 16, 2020, to 75-80% in January, 2021.

INTERPRETATION

Implementation of corticosteroids into clinical practice in the UK for patients with COVID-19 has been successful, but not universal. Patients older than 70 years, independent of illness severity, chronic neurological disease, and dementia, were less likely to receive corticosteroids than those who were younger, as were pregnant women. This could reflect appropriate clinical decision making, but the possibility of inequitable access to life-saving care should be considered.

FUNDING

UK National Institute for Health Research and UK Medical Research Council.

Genome-Wide Association Study of NAFLD Using Electronic Health Records

Genome-wide association studies (GWAS) have identified several risk loci for nonalcoholic fatty liver disease (NAFLD). Previous studies have largely relied on small sample sizes and have assessed quantitative traits. We performed a case-control GWAS in the UK Biobank using recorded diagnosis of NAFLD based on diagnostic codes recommended in recent consensus guidelines. We performed a GWAS of 4,761 cases of NAFLD and 373,227 healthy controls without evidence of NAFLD. Sensitivity analyses were performed excluding other co-existing hepatic pathology, adjusting for body mass index (BMI) and adjusting for alcohol intake. A total of 9,723,654 variants were assessed by logistic regression adjusted for age, sex, genetic principal components, and genotyping batch. We performed a GWAS meta-analysis using available summary association statistics. Six risk loci were identified (P < 5*10-8 ) (apolipoprotein E [APOE], patatin-like phospholipase domain containing 3 [PNPLA3, transmembrane 6 superfamily member 2 [TM6SF2], glucokinase regulator [GCKR], mitochondrial amidoxime reducing component 1 [MARC1], and tribbles pseudokinase 1 [TRIB1]). All loci retained significance in sensitivity analyses without co-existent hepatic pathology and after adjustment for BMI. PNPLA3 and TM6SF2 remained significant after adjustment for alcohol (alcohol intake was known in only 158,388 individuals), with others demonstrating consistent direction and magnitude of effect. All six loci were significant on meta-analysis. Rs429358 (P = 2.17*10-11 ) is a missense variant within the APOE gene determining ϵ4 versus ϵ2/ϵ3 alleles. The ϵ4 allele of APOE offered protection against NAFLD (odds ratio for heterozygotes 0.84 [95% confidence interval 0.78-0.90] and homozygotes 0.64 [0.50-0.79]). Conclusion: This GWAS replicates six known NAFLD-susceptibility loci and confirms that the ϵ4 allele of APOE is associated with protection against NAFLD. The results are consistent with published GWAS using histological and radiological measures of NAFLD, confirming that NAFLD identified through diagnostic codes from consensus guidelines is a valid alternative to more invasive and costly approaches.

Cytokines profile in neonatal and adult wild-type mice post-injection of U. S. pediatric vaccination schedule

Introduction

A recent study from our laboratory demonstrated a number of neurobehavioral abnormalities in mice colony injected with a mouse-weight equivalent dose of all vaccines that are administered to infants in their first 18 months of life according to the U. S. pediatric vaccination schedule.

Cytokines have been studied extensively as blood immune and inflammatory biomarkers, and their association with neurodevelopmental disorders. Given the importance of cytokines in early neurodevelopment, we aimed to investigate the potential post-administration effects of the U. S. pediatric vaccines on circulatory cytokines in a mouse model.

In the current study, cytokines have been assayed at early and late time points in mice vaccinated early in postnatal life and compared with placebo controls.

Materials and methods

Newborn mouse pups were divided into three groups: i) vaccine (V1), ii) vaccine ​× ​3 (V3) and iii) placebo control. V1 group was injected with mouse weight-equivalent of the current U. S. pediatric vaccine schedule. V3 group was injected with same vaccines but at triple the dose and the placebo control was injected with saline. Pups were also divided according to the sampling age into two main groups: acute- and chronic-phase group. Blood samples were collected at postnatal day (PND) 23, two days following vaccine schedule for the acute-phase group or at 67 weeks post-vaccination for the chronic-phase groups. Fifteen cytokines were analyzed: GM-CSF, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-17A, MCP-1, TNF-α, and VEGF-A. Wilcoxon Rank Sum test or unpaired Student's t-test was performed where applicable.

Results

IL-5 levels in plasma were significantly elevated in the V1 and V3 group compared with the control only in the acute-phase group. The elevation of IL-5 levels in the two vaccine groups were significant irrespective of whether the sexes were combined or analyzed separately. Other cytokines (VEGF-A, TNF-α, IL-10, MCP-1, GM-CSF, IL-6, and IL-13) were also impacted, although to a lesser extent and in a sex-dependent manner. In the acute-phase group, females showed a significant increase in IL-10 and MCP-1 levels and a decrease in VEGF-A levels in both V1 and V3 group compared to controls. In the acute-phase, a significant increase in MCP-1 levels in V3 group and CM-CSF levels in V1 and V3 group and decrease in TNF-α levels in V1 group were observed in treated males as compared with controls. In chronic-phase females, levels of VEGF-A in V1 and V3 group, TNF-α in V3 group, and IL-13 in V1 group were significantly decreased in contrast with controls. In chronic-phase males, TNF-α levels were significantly increased in V1 group and IL-6 levels decreased in V3 group in comparison to controls. The changes in levels of most tested cytokines were altered between the early and the late postnatal assays.

Conclusions

IL-5 levels significantly increased in the acute-phase of the treatment in the plasma of both sexes that were subjected to V1 and V3 injections. These increases had diminished by the second test assayed at week 67. These results suggest that a profound, albeit transient, effect on cytokine levels may be induced by the whole vaccine administration supporting our recently published observations regarding the behavioral abnormalities in the same mice. These observations support the view that the administration of whole pediatric vaccines in a neonatal period may impact at least short-term CNS functions in mice.

O8 Tracking wound infection with smartphone technology (twist): a randomised controlled trial in emergency surgery patients

Introduction

Surgical site infections (SSI) complicate 2%–10% of general surgery cases, and represent a significant burden on acute healthcare services. We aim to investigate if a smartphone-delivered wound assessment tool results in earlier treatment.

Method

This parallel, single-blinded randomised control trial enrolled adult emergency abdominal surgery patients in two tertiary hospitals (ClinicalTrials.gov number, NCT02704897). Patients were randomised (1:1 ratio) between standard postoperative care and additional access to a smartphone-delivered wound assessment tool for 30-days postoperatively. Patients routinely submitted wound questionnaires and photos for surgical review at postoperative days 3, 7, and 15. The primary outcome measure was time-to-diagnosis of SSI (CDC definition) within 30 postoperative days.

Result

492 patients undergoing emergency surgery were randomised (smartphone intervention = 223; standard care = 269). There was no significant difference (P = 0.513) in the 30-day SSI rate between trial arms: 21 (9.4%) in smartphone vs 20 (7.4%) in standard care. While the mean time-to-diagnosis of SSI was 9.3 days (SD = 6.3) in the smartphone group, and 11.8 days (SD = 6.7) in the control group, this did not demonstrate a significant difference for the primary outcome (P = 0.255). However, patients in the smartphone group had 3.7-fold higher odds to be diagnosed in first 7 postoperative days (95% CI: 1.02 to 13.51, P = 0.043).

Conclusion

Digital patient-driven postoperative wound follow-up can be feasibly delivered in a broad cohort of emergency surgery patients. This can facilitate triage of patients to the appropriate level of assessment required, allowing diagnosis of SSI earlier in the postoperative period.

Take-home Message

Digital patient-driven postoperative wound follow-up can be feasibly delivered in a broad cohort of emergency surgery patients. This can facilitate triage of patients to the appropriate level of assessment required, allowing diagnosis of SSI earlier in the postoperative period.

Characterisation of in-hospital complications associated with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol UK: a prospective, multicentre cohort study

BACKGROUND

COVID-19 is a multisystem disease and patients who survive might have in-hospital complications. These complications are likely to have important short-term and long-term consequences for patients, health-care utilisation, health-care system preparedness, and society amidst the ongoing COVID-19 pandemic. Our aim was to characterise the extent and effect of COVID-19 complications, particularly in those who survive, using the International Severe Acute Respiratory and Emerging Infections Consortium WHO Clinical Characterisation Protocol UK.

METHODS

We did a prospective, multicentre cohort study in 302 UK health-care facilities. Adult patients aged 19 years or older, with confirmed or highly suspected SARS-CoV-2 infection leading to COVID-19 were included in the study. The primary outcome of this study was the incidence of in-hospital complications, defined as organ-specific diagnoses occurring alone or in addition to any hallmarks of COVID-19 illness. We used multilevel logistic regression and survival models to explore associations between these outcomes and in-hospital complications, age, and pre-existing comorbidities.

FINDINGS

Between Jan 17 and Aug 4, 2020, 80 388 patients were included in the study. Of the patients admitted to hospital for management of COVID-19, 49·7% (36 367 of 73 197) had at least one complication. The mean age of our cohort was 71·1 years (SD 18·7), with 56·0% (41 025 of 73 197) being male and 81·0% (59 289 of 73 197) having at least one comorbidity. Males and those aged older than 60 years were most likely to have a complication (aged ≥60 years: 54·5% [16 579 of 30 416] in males and 48·2% [11 707 of 24 288] in females; aged <60 years: 48·8% [5179 of 10 609] in males and 36·6% [2814 of 7689] in females). Renal (24·3%, 17 752 of 73 197), complex respiratory (18·4%, 13 486 of 73 197), and systemic (16·3%, 11 895 of 73 197) complications were the most frequent. Cardiovascular (12·3%, 8973 of 73 197), neurological (4·3%, 3115 of 73 197), and gastrointestinal or liver (0·8%, 7901 of 73 197) complications were also reported.

INTERPRETATION

Complications and worse functional outcomes in patients admitted to hospital with COVID-19 are high, even in young, previously healthy individuals. Acute complications are associated with reduced ability to self-care at discharge, with neurological complications being associated with the worst functional outcomes. COVID-19 complications are likely to cause a substantial strain on health and social care in the coming years. These data will help in the design and provision of services aimed at the post-hospitalisation care of patients with COVID-19.

FUNDING

National Institute for Health Research and the UK Medical Research Council.

Development and validation of the ISARIC 4C Deterioration model for adults hospitalised with COVID-19: a prospective cohort study

BACKGROUND

Prognostic models to predict the risk of clinical deterioration in acute COVID-19 cases are urgently required to inform clinical management decisions.

METHODS

We developed and validated a multivariable logistic regression model for in-hospital clinical deterioration (defined as any requirement of ventilatory support or critical care, or death) among consecutively hospitalised adults with highly suspected or confirmed COVID-19 who were prospectively recruited to the International Severe Acute Respiratory and Emerging Infections Consortium Coronavirus Clinical Characterisation Consortium (ISARIC4C) study across 260 hospitals in England, Scotland, and Wales. Candidate predictors that were specified a priori were considered for inclusion in the model on the basis of previous prognostic scores and emerging literature describing routinely measured biomarkers associated with COVID-19 prognosis. We used internal-external cross-validation to evaluate discrimination, calibration, and clinical utility across eight National Health Service (NHS) regions in the development cohort. We further validated the final model in held-out data from an additional NHS region (London).

FINDINGS

74 944 participants (recruited between Feb 6 and Aug 26, 2020) were included, of whom 31 924 (43·2%) of 73 948 with available outcomes met the composite clinical deterioration outcome. In internal-external cross-validation in the development cohort of 66 705 participants, the selected model (comprising 11 predictors routinely measured at the point of hospital admission) showed consistent discrimination, calibration, and clinical utility across all eight NHS regions. In held-out data from London (n=8239), the model showed a similarly consistent performance (C-statistic 0·77 [95% CI 0·76 to 0·78]; calibration-in-the-large 0·00 [-0·05 to 0·05]); calibration slope 0·96 [0·91 to 1·01]), and greater net benefit than any other reproducible prognostic model.

INTERPRETATION

The 4C Deterioration model has strong potential for clinical utility and generalisability to predict clinical deterioration and inform decision making among adults hospitalised with COVID-19.

FUNDING

National Institute for Health Research (NIHR), UK Medical Research Council, Wellcome Trust, Department for International Development, Bill & Melinda Gates Foundation, EU Platform for European Preparedness Against (Re-)emerging Epidemics, NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections at University of Liverpool, NIHR HPRU in Respiratory Infections at Imperial College London.

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

BACKGROUND

80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality.

METHODS

This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494.

FINDINGS

Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70-8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39-8·80) and upper-middle-income countries (2·06, 1·11-3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26-11·59) and upper-middle-income countries (3·89, 2·08-7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications.

INTERPRETATION

Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications.

FUNDING

National Institute for Health Research Global Health Research Unit.

Reliability and accuracy of an expert physical therapist as a reference standard for a manual therapy joint mobilization trial

Objective: Previous studies on learning joint mobilization techniques have used expert practitioners as the reference standard as there is no current evidence on what ideal forces would be for effective mobilizations. However, none of these trials have documented the reliability or accuracy of the reference standard. Therefore, the purpose of this study was to report both the reliability and accuracy of an expert physical therapist (PT) acting as a reference standard for a manual therapy joint mobilization trial.Methods: A secondary analysis was performed using data from a published randomized, controlled, crossover study. The mobilization technique studied was the central posterior to anterior (PA) joint mobilization of the L3 vertebra. Reliability and accuracy data for the reference standard were collected over four time periods spanning 16 weeks.Results: Intrarater reliability of the expert PT for R1 and R2 joint forces was excellent (R1 Force ICC_3,3 0.95, 95%CI 0.76-0.99 and R2 Force ICC_3,3 0.90, 95%CI 0.49-0.99). Additionally, the expert PT was 92.3% accurate (mean % error±SD, 7.7 ± 5.5) when finding Grade III mean peak mobilization force and 85.1% accurate (mean % error±SD, 14.9 ± 8.3) when finding Grade IV mean peak mobilization force. Finally, correlations between actual applied forces and computed ideal forces were excellent (Pearson r 0.79-0.92, n = 24, P < 0.01 for all correlations).Discussion: The expert PT in this manual therapy joint mobilization trial showed excellent reliability and accuracy as the reference standard. The study supports the use of implementing quantitative feedback devices into the teaching of joint mobilization when a reliable and accurate reference standard has been identified.Level of Evidence: 2b.

Risk stratification of patients admitted to hospital with covid-19 using the ISARIC WHO Clinical Characterisation Protocol: development and validation of the 4C Mortality Score

OBJECTIVE

To develop and validate a pragmatic risk score to predict mortality in patients admitted to hospital with coronavirus disease 2019 (covid-19).

DESIGN

Prospective observational cohort study.

SETTING

International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) World Health Organization (WHO) Clinical Characterisation Protocol UK (CCP-UK) study (performed by the ISARIC Coronavirus Clinical Characterisation Consortium-ISARIC-4C) in 260 hospitals across England, Scotland, and Wales. Model training was performed on a cohort of patients recruited between 6 February and 20 May 2020, with validation conducted on a second cohort of patients recruited after model development between 21 May and 29 June 2020. PARTICIPANTS: Adults (age ≥18 years) admitted to hospital with covid-19 at least four weeks before final data extraction.

MAIN OUTCOME MEASURE

In-hospital mortality.

RESULTS

35 463 patients were included in the derivation dataset (mortality rate 32.2%) and 22 361 in the validation dataset (mortality rate 30.1%). The final 4C Mortality Score included eight variables readily available at initial hospital assessment: age, sex, number of comorbidities, respiratory rate, peripheral oxygen saturation, level of consciousness, urea level, and C reactive protein (score range 0-21 points). The 4C Score showed high discrimination for mortality (derivation cohort: area under the receiver operating characteristic curve 0.79, 95% confidence interval 0.78 to 0.79; validation cohort: 0.77, 0.76 to 0.77) with excellent calibration (validation: calibration-in-the-large=0, slope=1.0). Patients with a score of at least 15 (n=4158, 19%) had a 62% mortality (positive predictive value 62%) compared with 1% mortality for those with a score of 3 or less (n=1650, 7%; negative predictive value 99%). Discriminatory performance was higher than 15 pre-existing risk stratification scores (area under the receiver operating characteristic curve range 0.61-0.76), with scores developed in other covid-19 cohorts often performing poorly (range 0.63-0.73).

CONCLUSIONS

An easy-to-use risk stratification score has been developed and validated based on commonly available parameters at hospital presentation. The 4C Mortality Score outperformed existing scores, showed utility to directly inform clinical decision making, and can be used to stratify patients admitted to hospital with covid-19 into different management groups. The score should be further validated to determine its applicability in other populations.

STUDY REGISTRATION

ISRCTN66726260.

Can a smartphone-delivered tool facilitate the assessment of surgical site infection and result in earlier treatment? Tracking wound infection with smartphone technology (TWIST): protocol for a randomised controlled trial in emergency surgery patients

INTRODUCTION

National data suggest that surgical site infection (SSI) complicates 2%-10% of general surgery cases, although the patient-reported incidence is much higher. SSIs cause significant patient morbidity and represent a significant burden on acute healthcare services, in a cohort predominantly suitable for outpatient management. Over three-quarters of UK adults now own smartphones, which could be harnessed to improve access to care. We aim to investigate if a smartphone-delivered wound assessment tool results in earlier treatment.

METHODS AND ANALYSIS

This is a randomised controlled trial aiming to recruit 500 patients across National Health Service (NHS) hospitals. All emergency abdominal surgery patients over the age of 16 who own smartphones will be considered eligible, with the exclusion of those with significant visual impairment. Participants will be randomised in a 1:1 ratio between standard postoperative care and the intervention - use of the smartphone tool in addition to standard postoperative care. The main outcome measure will be time-to-diagnosis of SSI with secondary outcome measures considering use of emergency department and general practitioner services and patient experience. Follow-up will be conducted by clinicians blinded to group allocation. Analysis of time-to-diagnosis will be by comparison of means using an independent two sample t-test.

ETHICS AND DISSEMINATION

This is the first randomised controlled trial on the use of a smartphone-delivered wound assessment tool to facilitate the assessment of SSI and the impact on time-to-diagnosis. The intervention is being used in addition to standard postoperative care. The study design and protocol were reviewed and approved by Southeast Scotland Research and Ethics Committee (REC Ref: 16/SS/0072 24/05/2016). Study findings will be presented at academic conferences, published in peer-reviewed journals and are expected in 2020. A written lay summary will be available to study participants on request.

TRIAL REGISTRATION NUMBER

NCT02704897; Pre-results.

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

BACKGROUND

Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.

METHODS

This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.

FINDINGS

Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p<0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05-2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p<0·001).

INTERPRETATION

Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication.

FUNDING

DFID-MRC-Wellcome Trust Joint Global Health Trial Development Grant, National Institute of Health Research Global Health Research Unit Grant.

Decision modeling in donation after circulatory death liver transplantation

Donation after circulatory death (DCD) liver allografts are increasingly used for transplantation. However, the posttransplantation clinical and quality of life outcomes of DCD recipients are traditionally considered to be inferior compared with donation after brain death (DBD) allograft recipients. Decision making for such marginal organs can be difficult. This study investigated the optimal decision to accept or decline a DCD liver allograft for a patient based on their current health. A Markov decision process model was constructed to predict the 5-year clinical course of patients on the liver transplant waiting list. Clinical outcomes were determined from the UK transplant registry or appropriate literature. Quality-adjusted life years (QALYs) were determined using the condition-specific short form of liver disease quality of life (SF-LDQoL) questionnaire. There were 293/374 (78.3%) eligible patients who completed the SF-LDQoL questionnaire. A total of 73 respondents (24.9%) were before transplant and 220 were after transplant (DBD recipient, 56.3%; DCD recipient, 8.5%; ischemic cholangiopathy patient, 2.4%; retransplant recipient, 7.9%). Predictive modeling indicated that QALYs gained at 5 years were significantly higher in DCD recipients (3.77; 95% confidence interval [CI], 3.44-4.10) compared with those who remained on the waiting list for a DBD transplant with Model for End-Stage Liver Disease (MELD) scores of 15-20 (3.36; 95% CI, 3.28-3.43), or >20 (3.07; 95% CI, 3.00-3.14). There was no significant advantage for individuals with MELD scores <15 (3.55; 95% CI, 3.47-3.63). In conclusion, this model predicts that patients on the UK liver transplant waiting list with MELD scores >15 should receive an offered DCD allograft based on the QALYs gained at 5 years. This analysis only accounts for donor-recipient risk pairings seen in current practice. The optimal decision for patients with MELD scores <15 remains unclear. However, a survival benefit was observed when a DCD organ was accepted. Liver Transplantation 23 594-603 2017 AASLD.

Individual surgeon mortality rates: can outliers be detected? A national utility analysis

OBJECTIVES

There is controversy on the proposed benefits of publishing mortality rates for individual surgeons. In some procedures, analysis at the level of an individual surgeon may lack statistical power. The aim was to determine the likelihood that variation in surgeon performance will be detected using published outcome data.

DESIGN

A national analysis surgeon-level mortality rates to calculate the level of power for the reported mortality rate across multiple surgical procedures.

SETTING

The UK from 2010 to 2014.

PARTICIPANTS

Surgeons who performed colon cancer resection, oesophagectomy or gastrectomy, elective aortic aneurysm repair, hip replacement, bariatric surgery or thyroidectomy.

OUTCOMES

The likelihood of detecting an individual with a 30-day, 90-day or in-patient mortality rate of up to 5 times the national mean or median (as available). This was represented using a novel heat-map approach.

RESULTS

Overall mortality rates for the procedures ranged from 0.07% to 4.5% and mean/median surgeon volume was between 23 and 75 cases. The national median case volume for colorectal (n=55) and upper gastrointestinal (n=23) cancer resections provides around 20% power to detect a mortality rate of 3 times the national median, while, for hip replacement, this is a rate 5 times the national average. At the mortality rates reported for thyroid (0.08%) and bariatric (0.07%) procedures, it is unlikely a surgeon would perform a sufficient number of procedures in his/her entire career to stand a good chance of detecting a mortality rate 5 times the national average.

CONCLUSIONS

At present, surgeons with increased mortality rates are unlikely to be detected. Performance within an expected mortality rate range cannot be considered reliable evidence of acceptable performance. Alternative approaches should focus on commonly occurring meaningful outcome measures, with infrequent events analysed predominately at the hospital level.

Protein corona formation in bronchoalveolar fluid enhances diesel exhaust nanoparticle uptake and pro-inflammatory responses in macrophages

In biological fluids nanoparticles bind a range of molecules, particularly proteins, on their surface. The resulting protein corona influences biological activity and fate of nanoparticle in vivo. Corona composition is often determined by the biological milieu encountered at the entry portal into the body, and, can therefore, depend on the route of exposure to the nanoparticle. For environmental nanoparticles where exposure is by inhalation, this will be lung lining fluid. This study examined plasma and bronchoalveolar fluid (BALF) protein binding to engineered and environmental nanoparticles. We hypothesized that protein corona on nanoparticles would influence nanoparticle uptake and subsequent pro-inflammatory biological response in macrophages. All nanoparticles bound plasma and BALF proteins, but the profile of bound proteins varied between nanoparticles. Focusing on diesel exhaust nanoparticles (DENP), we identified proteins bound from plasma to include fibrinogen, and those bound from BALF to include albumin and surfactant proteins A and D. The presence on DENP of a plasma-derived corona or one of purified fibrinogen failed to evoke an inflammatory response in macrophages. However, coronae formed in BALF increased DENP uptake into macrophages two fold, and increased nanoparticulate carbon black (NanoCB) uptake fivefold. Furthermore, a BALF-derived corona increased IL-8 release from macrophages in response to DENP from 1720 ± 850 pg/mL to 5560 ± 1380 pg/mL (p = 0.014). These results demonstrate that the unique protein corona formed on nanoparticles plays an important role in determining biological reactivity and fate of nanoparticle in vivo. Importantly, these findings have implications for the mechanism of detrimental properties of environmental nanoparticles since the principle route of exposure to such particles is via the lung.

Platelet activation independent of pulmonary inflammation contributes to diesel exhaust particulate-induced promotion of arterial thrombosis

BACKGROUND

Accelerated thrombus formation induced by exposure to combustion-derived air pollution has been linked to alterations in endogenous fibrinolysis and platelet activation in response to pulmonary and systemic inflammation. We hypothesised that mechanisms independent of inflammation contribute to accelerated thrombus formation following exposure to diesel exhaust particles (DEP).

METHODS

Thrombosis in rats was assessed 2, 6 and 24 h after administration of DEP, carbon black (CB; control carbon nanoparticle), DQ12 quartz microparticles (to induce pulmonary inflammation) or saline (vehicle) by either intra-tracheal instillation (0.5 mg, except Quartz; 0.125 mg) or intravenous injection (0.5 mg/kg). Thrombogenicity was assessed by carotid artery occlusion, fibrinolytic variables and platelet-monocyte aggregates. Measures of inflammation were determined in plasma and bronchoalveolar lavage fluid. Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI)-1 were measured following direct in vitro exposure of human umbilical vein endothelial cells (HUVECs) to DEP (10-150 μg/mL).

RESULTS

Instillation of DEP reduced the time to thrombotic occlusion in vivo, coinciding with the peak of DEP-induced pulmonary inflammation (6 h). CB and DQ12 produced greater inflammation than DEP but did not alter time to thrombotic occlusion. Intravenous DEP produced an earlier (2 h) acceleration of thrombosis (as did CB) without pulmonary or systemic inflammation. DEP inhibited t-PA and PAI-1 release from HUVECs, and reduced the t-PA/PAI-1 ratio in vivo; similar effects in vivo were seen with CB and DQ12. DEP, but not CB or DQ12, increased platelet-monocyte aggregates.

CONCLUSION

DEP accelerates arterial thrombus formation through increased platelet activation. This effect is dissociated from pulmonary and systemic inflammation and from impaired fibrinolytic function.

Vaccine-associated varicella and rubella infections in severe combined immunodeficiency with isolated CD4 lymphocytopenia and mutations in IL7R detected by tandem whole exome sequencing and chromosomal microarray

In areas without newborn screening for severe combined immunodeficiency (SCID), disease-defining infections may lead to diagnosis, and in some cases, may not be identified prior to the first year of life. We describe a female infant who presented with disseminated vaccine-acquired varicella (VZV) and vaccine-acquired rubella infections at 13 months of age. Immunological evaluations demonstrated neutropenia, isolated CD4 lymphocytopenia, the presence of CD8(+) T cells, poor lymphocyte proliferation, hypergammaglobulinaemia and poor specific antibody production to VZV infection and routine immunizations. A combination of whole exome sequencing and custom-designed chromosomal microarray with exon coverage of primary immunodeficiency genes detected compound heterozygous mutations (one single nucleotide variant and one intragenic copy number variant involving one exon) within the IL7R gene. Mosaicism for wild-type allele (20-30%) was detected in pretransplant blood and buccal DNA and maternal engraftment (5-10%) demonstrated in pretransplant blood DNA. This may be responsible for the patient's unusual immunological phenotype compared to classical interleukin (IL)-7Rα deficiency. Disseminated VZV was controlled with anti-viral and immune-based therapy, and umbilical cord blood stem cell transplantation was successful. Retrospectively performed T cell receptor excision circle (TREC) analyses completed on neonatal Guthrie cards identified absent TREC. This case emphasizes the danger of live viral vaccination in severe combined immunodeficiency (SCID) patients and the importance of newborn screening to identify patients prior to high-risk exposures. It also illustrates the value of aggressive pathogen identification and treatment, the influence newborn screening can have on morbidity and mortality and the significant impact of newer genomic diagnostic tools in identifying the underlying genetic aetiology for SCID patients.

Pulmonary diesel particulate increases susceptibility to myocardial ischemia/reperfusion injury via activation of sensory TRPV1 and β1 adrenoreceptors

BACKGROUND

Clinical studies have now confirmed the link between short-term exposure to elevated levels of air pollution and increased cardiovascular mortality, but the mechanisms are complex and not completely elucidated. The present study was designed to investigate the hypothesis that activation of pulmonary sensory receptors and the sympathetic nervous system underlies the influence of pulmonary exposure to diesel exhaust particulate on blood pressure, and on the myocardial response to ischemia and reperfusion.

METHODS & RESULTS

6 h after intratracheal instillation of diesel exhaust particulate (0.5 mg), myocardial ischemia and reperfusion was performed in anesthetised rats. Blood pressure, duration of ventricular arrhythmia, arrhythmia-associated death, tissue edema and reperfusion injury were all increased by diesel exhaust particulate exposure. Reperfusion injury was also increased in buffer perfused hearts isolated from rats instilled in vivo, excluding an effect dependent on continuous neurohumoral activation or systemic inflammatory mediators. Myocardial oxidant radical production, tissue apoptosis and necrosis were increased prior to ischemia, in the absence of recruited inflammatory cells. Intratracheal application of an antagonist of the vanilloid receptor TRPV1 (AMG 9810, 30 mg/kg) prevented enhancement of systolic blood pressure and arrhythmia in vivo, as well as basal and reperfusion-induced myocardial injury ex vivo. Systemic β1 adrenoreceptor antagonism with metoprolol (10 mg/kg) also blocked enhancement of myocardial oxidative stress and reperfusion injury.

CONCLUSIONS

Pulmonary diesel exhaust particulate increases blood pressure and has a profound adverse effect on the myocardium, resulting in tissue damage, but also increases vulnerability to ischemia-associated arrhythmia and reperfusion injury. These effects are mediated through activation of pulmonary TRPV1, the sympathetic nervous system and locally generated oxidative stress.

Diesel exhaust particulate increases the size and complexity of lesions in atherosclerotic mice

Objective

Diesel exhaust particulate (DEP), a major component of urban air pollution, has been linked to atherogenesis and precipitation of myocardial infarction. We hypothesized that DEP exposure would increase and destabilise atherosclerotic lesions in apolipoprotein E deficient (ApoE^−/−) mice.

Methods

ApoE^−/− mice were fed a ‘Western diet’ (8 weeks) to induce ‘complex’ atherosclerotic plaques, with parallel experiments in normal chow fed wild-type mice. During the last 4 weeks of feeding, mice received twice weekly instillation (oropharyngeal aspiration) of 35 μL DEP (1 mg/mL, SRM-2975) or vehicle (saline). Atherosclerotic burden was assessed by en-face staining of the thoracic aorta and histological examination of the brachiocephalic artery.

Results

Brachiocephalic atherosclerotic plaques were larger in ApoE^−/− mice treated with DEP (59±10%) than in controls (32±7%; P = 0.017). In addition, DEP-treated mice had more plaques per section of artery (2.4±0.2 vs 1.8±0.2; P = 0.048) and buried fibrous layers (1.2±0.2 vs 0.4±0.1; P = 0.028). These changes were associated with lung inflammation and increased antioxidant gene expression in the liver, but not with changes in endothelial function, plasma lipids or systemic inflammation.

Conclusions

Increased atherosclerosis is caused by the particulate component of diesel exhaust producing advanced plaques with a potentially more vulnerable phenotype. These results are consistent with the suggestion that removal of the particulate component would reduce the adverse cardiovascular effects of diesel exhaust.

Nanoparticles and the cardiovascular system: a critical review

Nanoparticles (NPs) are tiny particles with a diameter of less than 100 nm. Traffic exhaust is a major source of combustion-derived NPs (CDNPs), which represent a significant component in urban air pollution. Epidemiological, panel and controlled human chamber studies clearly demonstrate that exposure to CDNPs is associated with multiple adverse cardiovascular effects in both healthy individuals and those with pre-existing cardiovascular disease. NPs are also manufactured from a large range of materials for industrial use in a vast array of products including for use as novel imaging agents for medical use. There is currently little information available on the impacts of manufactured NPs in humans, but experimental studies demonstrate similarities to the detrimental cardiovascular actions of CDNPs. This review describes the evidence for these cardiovascular effects and attempts to resolve the paradox between the adverse effects of the unintentional exposure of CDNPs and the intentional delivery of manufactured NPs for medical purposes.

From particles to patients: oxidative stress and the cardiovascular effects of air pollution

Air pollution, especially airborne particulate matter (PM), is associated with an increase in both morbidity and mortality from cardiovascular disease, although the underlying mechanisms remain incompletely established. The one consistent observation that links the pulmonary and cardiovascular effects of inhaled PM is oxidative stress. This article examines the evidence for the role of oxidative stress in the cardiovascular effects of air pollution, beginning with observations from epidemiological and controlled exposure studies and then exploring potential mechanistic pathways involving free radical generation from PM itself, to effects of PM on cell cultures, isolated organs, healthy animals and animal models of disease. Particular emphasis is placed on the vascular and atherosclerotic effects of urban air pollution and diesel exhaust emissions as rich sources of environmental ultrafine particles.

Integrated copy number and gene expression analysis detects a CREB1 association with Alzheimer's disease

Genetic variation, both single-nucleotide variations and copy number variations (CNV), contribute to changes in gene expression. In some cases these variations are meaningfully correlated with disease states. We hypothesized that in a genetically heterogeneous disorder such as sporadic Alzheimer's disease (AD), utilizing gene expression as a quantitative trait and CNVs as a genetic marker map within the same individuals in the context of case-control status may increase the power to detect relevant loci. Using this approach an 8-kb deletion was identified that contains a PAX6-binding site on chr2q33.3 upstream of CREB1 encoding the cAMP responsive element-binding protein1 transcription factor. The association of the CNV to AD was confirmed by a case-control association study consisting of the Texas Alzheimer Research and Care Consortium and NIA-LOAD Family Study data sets.

In vivo mononuclear cell tracking using superparamagnetic particles of iron oxide: feasibility and safety in humans

BACKGROUND

Cell therapy is an emerging and exciting novel treatment option for cardiovascular disease that relies on the delivery of functional cells to their target site. Monitoring and tracking cells to ensure tissue delivery and engraftment is a critical step in establishing clinical and therapeutic efficacy. The study aims were (1) to develop a Good Manufacturing Practice-compliant method of labeling competent peripheral blood mononuclear cells with superparamagnetic particles of iron oxide (SPIO), and (2) to evaluate its potential for magnetic resonance cell tracking in humans.

METHODS AND RESULTS

Peripheral blood mononuclear cells 1-5 × 10(9) were labeled with SPIO. SPIO-labeled cells had similar in vitro viability, migratory capacity, and pattern of cytokine release to unlabeled cells. After intramuscular administration, up to 10(8) SPIO-labeled cells were readily identifiable in vivo for at least 7 days using magnetic resonance imaging scanning. Using a phased-dosing study, we demonstrated that systemic delivery of up to 10(9) SPIO-labeled cells in humans is safe, and cells accumulating in the reticuloendothelial system were detectable on clinical magnetic resonance imaging. In a healthy volunteer model, a focus of cutaneous inflammation was induced in the thigh by intradermal injection of tuberculin. Intravenously delivered SPIO-labeled cells tracked to the inflamed skin and were detectable on magnetic resonance imaging. Prussian blue staining of skin biopsies confirmed iron-laden cells in the inflamed skin.

CONCLUSIONS

Human peripheral blood mononuclear cells can be labeled with SPIO without affecting their viability or function. SPIO labeling for magnetic resonance cell tracking is a safe and feasible technique that has major potential for a range of cardiovascular applications including monitoring of cell therapies and tracking of inflammatory cells. Clinical Trial Registration- URL: http://www.clinicaltrials.gov; Unique identifier: NCT00972946, NCT01169935.

Diesel exhaust particulate induces pulmonary and systemic inflammation in rats without impairing endothelial function ex vivo or in vivo

Background

Inhalation of diesel exhaust impairs vascular function in man, by a mechanism that has yet to be fully established. We hypothesised that pulmonary exposure to diesel exhaust particles (DEP) would cause endothelial dysfunction in rats as a consequence of pulmonary and systemic inflammation.

Methods

Wistar rats were exposed to DEP (0.5 mg) or saline vehicle by intratracheal instillation and hind-limb blood flow, blood pressure and heart rate were monitored in situ 6 or 24 h after exposure. Vascular function was tested by administration of the endothelium-dependent vasodilator acetylcholine (ACh) and the endothelium-independent vasodilator sodium nitroprusside (SNP) in vivo and ex vivo in isolated rings of thoracic aorta, femoral and mesenteric artery from DEP exposed rats. Bronchoalveolar lavage fluid (BALF) and blood plasma were collected to assess pulmonary (cell differentials, protein levels & interleukin-6 (IL-6)) and systemic (IL-6), tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP)) inflammation, respectively.

Results

DEP instillation increased cell counts, total protein and IL-6 in BALF 6 h after exposure, while levels of IL-6 and TNFα were only raised in blood 24 h after DEP exposure. DEP had no effect on the increased hind-limb blood flow induced by ACh in vivo at 6 or 24 h. However, responses to SNP were impaired at both time points. In contrast, ex vivo responses to ACh and SNP were unaltered in arteries isolated from rats exposed to DEP.

Conclusions

Exposure of rats to DEP induces both pulmonary and systemic inflammation, but does not modify endothelium-dependent vasodilatation. Other mechanisms in vivo limit dilator responses to SNP and these require further investigation.

Mechanisms of aluminum adjuvant toxicity and autoimmunity in pediatric populations

Immune challenges during early development, including those vaccine-induced, can lead to permanent detrimental alterations of the brain and immune function. Experimental evidence also shows that simultaneous administration of as little as two to three immune adjuvants can overcome genetic resistance to autoimmunity. In some developed countries, by the time children are 4 to 6 years old, they will have received a total of 126 antigenic compounds along with high amounts of aluminum (Al) adjuvants through routine vaccinations. According to the US Food and Drug Administration, safety assessments for vaccines have often not included appropriate toxicity studies because vaccines have not been viewed as inherently toxic. Taken together, these observations raise plausible concerns about the overall safety of current childhood vaccination programs. When assessing adjuvant toxicity in children, several key points ought to be considered: (i) infants and children should not be viewed as “small adults” with regard to toxicological risk as their unique physiology makes them much more vulnerable to toxic insults; (ii) in adult humans Al vaccine adjuvants have been linked to a variety of serious autoimmune and inflammatory conditions (i.e., “ASIA”), yet children are regularly exposed to much higher amounts of Al from vaccines than adults; (iii) it is often assumed that peripheral immune responses do not affect brain function. However, it is now clearly established that there is a bidirectional neuro-immune cross-talk that plays crucial roles in immunoregulation as well as brain function. In turn, perturbations of the neuro-immune axis have been demonstrated in many autoimmune diseases encompassed in “ASIA” and are thought to be driven by a hyperactive immune response; and (iv) the same components of the neuro-immune axis that play key roles in brain development and immune function are heavily targeted by Al adjuvants. In summary, research evidence shows that increasing concerns about current vaccination practices may indeed be warranted. Because children may be most at risk of vaccine-induced complications, a rigorous evaluation of the vaccine-related adverse health impacts in the pediatric population is urgently needed.

Abstract P312: Tracheal Instillation of Diesel Exhaust Particles Exacerbates Myocardial Ischaemia and Reperfusion Injury in Rats

Episodes of increased air pollution are associated with higher cardiovascular mortality. The adverse effects of air pollution have been attributed to particulate matter, especially ultrafine particles. This study addresses the hypothesis that ultrafine diesel exhaust particles (DEP) exacerbate myocardial ischaemia reperfusion (I/R) injury secondary to induction of a systemic inflammatory response. Wistar rats (n=5–6/group) received DEP (0.5 mg) or saline vehicle by intratracheal instillation. 6h later I/R was induced either in vivo or ex vivo in isolated buffer perfused hearts. Lung inflammation was confirmed 6h after DEP instillation by increased levels of neutrophils, total protein and IL-6 in bronchoalveolar lavage fluid. However, there was no evidence for systemic inflammation as assessed by plasma cytokine levels (IL-6, TNF-α, and CRP) or by neutrophil priming (CD11b expression) or activation (CD62L expression). In vivo , systolic blood pressure was significantly higher in DEP-instilled rats (129 ± 7 mmHg) than in saline controls (92 ± 3 mmHg, P<0.01), consistent with increased autonomic activation. Arrhythmias occurred intermittently after induction of ischaemia (in total 8.2±1.2 s in the saline group) and were more prevalent in DEP-instilled rats (32.9±5.0s, P<0.001). Fatal arrhythmias occurred in 60% of rats receiving DEP but not at all in saline controls. Following reperfusion, infarct size (extent of triphenyltetrazolium chloride staining) was significantly increased after DEP (34.7 ± 1.2% left ventricle) vs saline-instilled (10.3 ± 1.2%, P<0.001). Infarct size was similarly potentiated in hearts isolated from DEP instilled rats and perfused ex-vivo . Histological examination confirmed the absence of inflammatory infiltrate in hearts prior to I/R. Prior exposure to pollution in vivo thus renders the heart more vulnerable to I/R injury, either in situ in the body or ex vivo when the heart is isolated from systemic mediators and cells. Systemic inflammation does not appear to be necessary for this ‘priming’ effect of DEP. The role of autonomic activation in promoting cardiac arrythmia in vivo after DEP instillation and in determining the ability of the heart to withstand subsequent I/R injury merits further investigation.

Aluminum vaccine adjuvants: are they safe?

Aluminum is an experimentally demonstrated neurotoxin and the most commonly used vaccine adjuvant. Despite almost 90 years of widespread use of aluminum adjuvants, medical science's understanding about their mechanisms of action is still remarkably poor. There is also a concerning scarcity of data on toxicology and pharmacokinetics of these compounds. In spite of this, the notion that aluminum in vaccines is safe appears to be widely accepted. Experimental research, however, clearly shows that aluminum adjuvants have a potential to induce serious immunological disorders in humans. In particular, aluminum in adjuvant form carries a risk for autoimmunity, long-term brain inflammation and associated neurological complications and may thus have profound and widespread adverse health consequences. In our opinion, the possibility that vaccine benefits may have been overrated and the risk of potential adverse effects underestimated, has not been rigorously evaluated in the medical and scientific community. We hope that the present paper will provide a framework for a much needed and long overdue assessment of this highly contentious medical issue.

Olfactory copy number association with age at onset of Alzheimer disease

OBJECTIVES

Copy number variants (CNVs) have been recognized as a source of genetic variation that contributes to disease phenotypes. Alzheimer disease (AD) has high heritability for occurrence and age at onset (AAO). We performed a cases-only genome-wide CNV association study for age at onset of AD.

METHODS

The discovery case series (n = 40 subjects with AD) was evaluated using array comparative genome hybridization (aCGH). A replication case series (n = 507 subjects with AD) was evaluated using Affymetrix array (n = 243) and multiplex ligation-dependent probe amplification (n = 264). Hazard models related onset age to CNV.

RESULTS

The discovery sample identified a chromosomal segment on 14q11.2 (19.3-19.5 Mb, NCBI build 36, UCSC hg18 March 2006) as a region of interest (genome-wide adjusted p = 0.032) for association with AAO of AD. This region encompasses a cluster of olfactory receptors. The replication sample confirmed the association (p = 0.035). The association was found for each APOE4 gene dosage (0, 1, and 2).

CONCLUSION

High copy number in the olfactory receptor region on 14q11.2 is associated with younger age at onset of AD.

Differential susceptibility to nitric oxide-evoked apoptosis in human inflammatory cells

Apoptosis of neutrophils and their subsequent phagocytosis is critical to the successful resolution of inflammation. During inflammation, activated inflammatory cells generate reactive oxygen and nitrogen species, including nitric oxide (NO) and superoxide anion (O(2)(•-)), which rapidly combine to generate peroxynitrite (ONOO(-)). NO and ONOO(-) are proapoptotic in human neutrophils. This study examines the effects of NO and ONOO(-) on caspase activation and mitochondrial permeability in human neutrophils and determines the ability of these species to evoke apoptosis in human monocyte-derived macrophages (MDMs). NO or ONOO(-) release from donor compounds was characterized by electrochemistry and electron paramagnetic resonance. Neutrophils and MDMs isolated from the peripheral blood of healthy volunteers were exposed to NO or ONOO(-) before analysis of apoptosis by caspase activation, mitochondrial permeability, and annexin V binding. Both NO and ONOO(-) induced apoptosis via rapid activation of caspases 2 and 3 in neutrophils. In contrast, only ONOO(-) promoted apoptosis in MDMs, whereas a variety of NO donors were ineffective at inducing apoptosis in this cell type. We propose that human macrophages are refractory to NO-stimulated apoptosis in order that they persist long enough within the inflammatory focus to phagocytose apoptotic neutrophils, thereby ensuring successful resolution of inflammation.

Abstract S6-10: Identification of a Novel Tumor Suppressor Network Reveals a Role for Proto-Oncogenic Receptor Tyrosine Kinases in Triple-Negative Breast Cancer

Breast cancer is a collection of diseases with distinct clinical behaviors and underlying genetic causes. Triple-negative breast cancer (TNBC) is a common subtype of breast cancer that confers a particularly poor prognosis and is refractory to current targeted therapies. Unfortunately, the molecular determinants driving this aggressive malignancy are poorly understood. Using an unbiased genetic screen, we have identified a novel tumor suppressor network that governs proliferation and transformation of TNBCs in vitro and in vivo. We define SECT21 as a core component in this network and a commonly inactivated tumor suppressor in TNBC. SECT21 is a potent suppressor of human mammary epithelial cell proliferation and transformation. SECT21 function is frequently compromised in human TNBCs by inactivating mutations, deletion, or loss of protein expression. Mechanistically, SECT21 is a tyrosine phosphatase that suppresses cellular transformation by interacting with and inhibiting several oncogenic receptor tyrosine kinases including HER2, EGFR, and PDGFR. Notably, the tumorigenic and metastatic potential of SECT21-deficient TNBCs is severely impaired by restoring SECT21 function or by inhibiting kinase targets of SECT21, suggesting that TNBCs are dependent on the proto-oncogenic tyrosine kinases constrained by SECT21. Collectively, these data identify SECT21 as a commonly inactivated tumor suppressor and provide a rationale for combinatorially targeting tyrosine kinases in TNBC and other cancers based on their profile of tyrosine phosphatase activity.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S6-10.

Diesel exhaust particulate--exposed macrophages cause marked endothelial cell activation

Exposure to air pollution containing diesel exhaust particulate (DEP) is linked to adverse cardiovascular events. This study tested the hypothesis that DEP not only causes direct endothelial cell injury, but also induces indirect endothelial cell activation via the release of soluble proinflammatory cytokines from macrophages. Human umbilical vein endothelial cells (HUVECs) and monocyte-derived macrophages (MDMs) were incubated with DEP (1-100 μg/ml; 24 h). Supernatants were analyzed for monocyte chemotactic protein (MCP)-1, IL6, IL8, and TNF-α. Indirect actions of DEP were investigated by incubating HUVECs with conditioned media from DEP-exposed MDMs in the presence and absence of the TNF-α inhibitor, etanercept. A modified Boyden chamber assay was used to determine whether HUVECs treated in this manner induced monocyte chemotaxis. Direct incubation with DEP induced a modest increase in MCP-1 concentration, but had no effect on IL-6 or IL-8 release from HUVECs. In contrast, direct treatment of MDMs with DEP had no effect on MCP-1, but elevated IL-8 and TNF-α concentrations. Incubation with conditioned media from DEP-exposed MDMs caused a dramatic amplification in MCP-1 and IL-6, but not IL-8, release from HUVECs. The potentiation of HUVEC activation was suppressed by TNF-α inhibition. MCP-1- and IL-6-containing HUVEC supernatants caused increased monocyte chemotaxis that was not inhibited by anti-MCP-1 antibodies. We conclude that DEP has only modest direct endothelial effects. In contrast, proinflammatory cytokines released from particle-laden MDMs appear to exacerbate endothelial activation after DEP exposure.

First record of giant anteater (xenarthra, myrmecophagidae) in north america

A right metacarpal III represents the first North American record of the giant anteater (Myrmecophaga tridactyla). Recovered in northwestern Sonora, Mexico, with a rich vertebrate fauna of early Pleistocene (Irvingtonian) age, it belongs to a cohort of large mammals that dispersed from South America to North America along a savanna corridor. Presumably habitat and climatic changes have subsequently driven this mammalian family more than 3000 kilometers back into Central America from its former expansion into temperate North America.

Cyclic GMP protects human macrophages against peroxynitrite-induced apoptosis

Background

Nitric oxide (NO) can be both pro- and anti-apoptotic in various cell types, including macrophages. This apparent paradox may result from the actions of NO-related species generated in the microenvironment of the cell, for example the formation of peroxynitrite (ONOO^-). In this study we have examined the ability of NO and ONOO^- to evoke apoptosis in human monocyte-derived macrophages (MDMϕ), and investigated whether preconditioning by cyclic guanosine monophosphate (cGMP) is able to limit apoptosis in this cell type.

Methods

Characterisation of the NO-related species generated by (Z)-1- [2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA/NO) and 1,2,3,4-oxatriazolium, 5-amino-3-(3,4-dichlorophenyl)-, chloride (GEA-3162) was performed by electrochemistry using an isolated NO electrode and electron paramagnetic resonance (EPR) spectrometry. Mononuclear cells were isolated from peripheral blood of healthy volunteers and cultured to allow differentiation into MDMϕ. Resultant MDMϕ were treated for 24 h with DETA/NO (100 – 1000 μM) or GEA-3162 (10 – 300 μM) in the presence or absence of BAY 41–2272 (1 μM), isobutylmethylxanthine (IBMX; 1 μM), 1H- [1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ; 20 μM) or 8-bromo-cGMP (1 mM). Apoptosis in MDMϕ was assessed by flow cytometric analysis of annexin V binding in combination with propidium iodide staining.

Results

Electrochemistry and EPR revealed that DETA/NO liberated free NO radical, whilst GEA-3162 concomitantly released NO and O₂^-, and is therefore a ONOO^- generator. NO (DETA/NO) had no effect on cell viability, but ONOO^- (GEA-3162) caused a concentration-dependent induction of apoptosis in MDMϕ. Preconditioning of MDMϕ with NO in combination with the phosphodiesterase inhibitor, 3-Isobutyl-1-methylxanthine (IBMX), or the NO-independent stimulator of soluble guanylate cyclase, BAY 41–2272, significantly attenuated ONOO^--induced apoptosis in a cGMP-dependent manner.

Conclusion

These results demonstrate disparities between the ability of NO and ONOO^- to induce apoptosis in human MDMϕ. Furthermore, this study provides evidence for a novel cGMP-dependent pre-conditioning mechanism to limit ONOO^--induced apoptosis in human MDMϕ.

Direct impairment of vascular function by diesel exhaust particulate through reduced bioavailability of endothelium-derived nitric oxide induced by superoxide free radicals

BACKGROUND

Diesel exhaust particulate (DEP) is a key arbiter of the adverse cardiovascular effects of air pollution.

OBJECTIVES

We assessed the in vitro effects of DEP on vascular function, nitric oxide (NO) availability, and the generation of oxygen-centered free radicals.

METHODS

We assessed the direct vascular effects of DEP (10-100 microg/mL) in isolated rat aortic rings using myography. We investigated NO scavenging and oxygen-centered free radical generation using an NO electrode and electron paramagnetic resonance (EPR) with the Tempone-H (1-hydroxyl-2,2,6,6-tetramethyl-4-oxo-piperidine) spin trap, respectively.

RESULTS

Acetylcholine-induced relaxation was attenuated by DEP (maximum relaxation reduced from 91 +/- 4% to 49 +/- 6% with 100 microg/mL DEP; p < 0.001) but was restored by superoxide dismutase (SOD; maximum relaxation, 73 +/- 6%; p < 0.001). DEP caused a modest inhibition of relaxation to NO donor drugs, an effect that could be reversed by SOD (p < 0.01). At 10 microg/mL, DEP did not affect verapamil-induced relaxation (p = 0.73), but at 100 microg/mL DEP inhibited relaxation (p < 0.001) by a mechanism independent of SOD. NO concentrations generated by 2-(N,N-diethylamino)-diazenolate-2-oxide (DEA/NO; 10 microM) were reduced by DEP (100 microg/mL; from 5.2 +/- 0.4 to 3.3 +/- 0.4 microM; p = 0.002). Free radical generation was increased by DEP (10 microg/mL; 9-fold increase in EPR spectra; p = 0.004) in a manner that could be attenuated by SOD (p = 0.015).

CONCLUSIONS

DEP caused oxidative stress through the generation of oxygen-centered free radicals that reduced the bioavailability of endothelium-derived NO without prior interaction with the lung or vascular tissue. These findings provide a mechanism for the adverse cardiovascular effects of particulate air pollution.

Dominant versus recessive traits conveyed by allelic mutations - to what extent is nonsense-mediated decay involved?

Mutations in ROR2, encoding a receptor tyrosine kinase, can cause autosomal recessive Robinow syndrome (RRS), a severe skeletal dysplasia with limb shortening, brachydactyly, and a dysmorphic facial appearance. Other mutations in ROR2 result in the autosomal dominant disease, brachydactyly type B (BDB1). No functional mechanisms have been delineated to effectively explain the association between mutations and different modes of inheritance causing different phenotypes. BDB1-causing mutations in ROR2 result from heterozygous premature termination codons (PTCs) in downstream exons and the conveyed phenotype segregates as an autosomal dominant trait, whereas heterozygous missense mutations and PTCs in upstream exons result in carrier status for RRS. Given that the distribution of PTC mutations revealed a correlation between the phenotype and the mode of inheritance conveyed, we investigated the potential role for the nonsense-mediated decay (NMD) pathway in the abrogation of possible aberrant effects of selected mutant alleles. Our experiments show that triggering or escaping NMD may cause different phenotypes with a distinct mode of inheritance. We generalize these findings to other disease-associated genes by examining PTC mutation distribution correlation with conveyed phenotype and inheritance patterns. Indeed, NMD may explain distinct phenotypes and different inheritance patterns conveyed by allelic truncating mutations enabling better genotype-phenotype correlations in several other disorders.

Chronic exposure to dietary sterol glucosides is neurotoxic to motor neurons and induces an ALS-PDC phenotype

Epidemiological studies of the Guamanian variants of amyotrophic lateral sclerosis (ALS) and parkinsonism, amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC), have shown a positive correlation between consumption of washed cycad seed flour and disease occurrence. Previous in vivo studies by our group have shown that the same seed flour induces ALS and PDC phenotypes in out bred adult male mice. In vitro studies using isolated cycad compounds have also demonstrated that several of these are neurotoxic, specifically, a number of water insoluble phytosterol glucosides of which beta-sitosterol beta-D: -glucoside (BSSG) forms the largest fraction. BSSG is neurotoxic to motor neurons and other neuronal populations in culture. The present study shows that an in vitro hybrid motor neuron (NSC-34) culture treated with BSSG undergoes a dose-dependent cell loss. Surviving cells show increased expression of HSP70, decreased cytosolic heavy neurofilament expression, and have various morphological abnormalities. CD-1 mice fed mouse chow pellets containing BSSG for 15 weeks showed motor deficits and motor neuron loss in the lumbar and thoracic spinal cord, along with decreased glutamate transporter labelling, and increased glial fibrillary acid protein reactivity. Other pathological outcomes included increased caspase-3 labelling in the striatum and decreased tyrosine-hydroxylase labelling in the striatum and substantia nigra. C57BL/6 mice fed BSSG-treated pellets for 10 weeks exhibited progressive loss of motor neurons in the lumbar spinal cord that continued to worsen even after the BSSG exposure ended. These results provide further support implicating sterol glucosides as one potential causal factor in the motor neuron pathology previously associated with cycad consumption and ALS-PDC.

Magnetic resonance microscopy and immunohistochemistry of the CNS of the mutant SOD murine model of ALS reveals widespread neural deficits

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that primarily affects motor neurons and descending motor tracts of the CNS. We have evaluated the CNS of a murine model of familial ALS based on the over-expression of mutant human superoxide dismutase (mSOD; G93A) using magnetic resonance microscopy (MRM) and immunohistochemistry (IHC). Three-dimensional volumetric analysis was performed from 3D T2*-weighted images acquired at 17.6 T at isotropic resolutions of 40 mum. Compared to controls, mSOD mice had significant reductions in the volumes of total brain, substantia nigra, striatum, hippocampus, and internal capsule, with decreased cortical thickness in primary motor and somatosensory cortices. In the spinal cord, mSOD mice had significantly decreased volume of both the total grey and white matter; in the latter case, the volume change was confined to the dorsal white matter. Increased apoptosis, GFAP positive astrocytes, and/or activated microglia were observed in all those CNS regions that showed volume loss except for the hippocampus. The MRM findings in mSOD over-expressing mice are similar to data previously obtained from a model of ALS-parkinsonism dementia complex (ALS-PDC), in which neural damage occurred following a diet of washed cycad flour containing various neurotoxins. The primary difference between the two models involves a significantly greater decrease in spinal cord white matter volume in mSOD mice, perhaps reflecting variations in degeneration of the descending motor tracts. The extent to which several CNS structures are impacted in both murine models of ALS argues for a reevaluation of the nature of the pathogenesis of ALS since CNS structures involved in Parkinson's and Alzheimer's diseases appear to be affected as well.

Sildenafil reduces alcohol-induced gastric damage: just say 'NO'

Although sildenafil (Viagra) and other phosphodiesterase V (PDE V) inhibitors are increasingly recognized for their use in the treatment of male erectile dysfunction and perhaps more recently pulmonary artery hypertension, less is known of their potential beneficial effects in other situations. Medeiros et al., in the current issue of the British Journal of Pharmacology, report that sildenafil dramatically reduces alcohol-induced gastric damage in rats. The authors provide convincing evidence that such protection not only occurs via the nitric oxide (NO)/cGMP pathway, but also involves regulation of ATP-sensitive potassium channels. Therefore, in addition to exerting anti-impotence efficacy, PDE V inhibitors may provide significant beneficial effects from mucosal injury induced by alcohol.

Taurine release in developing mouse hippocampus is modulated by glutathione and glutathione derivatives

Glutathione (reduced form GSH and oxidized form GSSG) constitutes an important defense against oxidative stress in the brain, and taurine is an inhibitory neuromodulator particularly in the developing brain. The effects of GSH and GSSG and glycylglycine, gamma-glutamylcysteine, cysteinylglycine, glycine and cysteine on the release of [(3)H]taurine evoked by K+-depolarization or the ionotropic glutamate receptor agonists glutamate, kainate, 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) were now studied in slices from the hippocampi from 7-day-old mouse pups in a perfusion system. All stimulatory agents (50 mM K(+), 1 mM glutamate, 0.1 mM kainate, 0.1 mM AMPA and 0.1 mM NMDA) evoked taurine release in a receptor-mediated manner. Both GSH and GSSG significantly inhibited the release evoked by 50 mM K+. The release induced by AMPA and glutamate was also inhibited, while the kainate-evoked release was significantly activated by both GSH and GSSG. The NMDA-evoked release proved the most sensitive to modulation: L-Cysteine and glycine enhanced the release in a concentration-dependent manner, whereas GSH and GSSG were inhibitory at low (0.1 mM) but not at higher (1 or 10 mM) concentrations. The release evoked by 0.1 mM AMPA was inhibited by gamma-glutamylcysteine and cysteinylglycine, whereas glycylglycine had no effect. The 0.1 mM NMDA-evoked release was inhibited by glycylglycine and gamma-glutamylcysteine. In turn, cysteinylglycine inhibited the NMDA-evoked release at 0.1 mM, but was inactive at 1 mM. Glutathione exhibited both enhancing and attenuating effects on taurine release, depending on the glutathione concentration and on the agonist used. Both glutathione and taurine act as endogenous neuroprotective effectors during early postnatal life.

Late appearance of glutamate transporter defects in a murine model of ALS–parkinsonism dementia complex

Excitotoxicity has been widely hypothesized to play a major role in various neurodegenerative diseases. We have used a mouse model of ALS-parkinsonism dementia complex (ALS-PDC) of the Western Pacific to explore this hypothesis. Mice fed washed cycad flour, the major epidemiological link to ALS-PDC, showed significant and progressive motor, cognitive, and sensory behavioural deficits [Wilson, J.M., Khabazian, I., Wong, M.C., Seyedalikhani, A., Bains, J.S., Pasqualotto, B.A., Williams, D.E., Andersen, R.J., Simpson, R.J., Smith, R., Craig, U.K., Kurland, L.T., Shaw, C.A., 2002. Behavioral and neurological correlates of ALS-parkinsonism dementia complex in adult mice fed washed cycad flour. Neuromol. Med. 1 (3), 207-221]. In addition, glutamate transporter (GLT-1/EAAT2) levels measured by immunohistochemistry with antibodies specific for two glial glutamate transporter splice variants (GLT-1alpha and GLT-1B) were significantly down-regulated showing a 'patchy' loss of antibody label centered on blood vessels [Wilson, J.M., Khabazian, I., Pow, D.V., Craig, U.K., Shaw, C.A., 2003. Decrease in glial glutamate transporter variants and excitatory amino acid receptor down-regulation in a murine model of ALS-PDC. Neuromol. Med. 3 (2), 105-118]. Receptor binding assays showed decreased NMDA and AMPA receptor levels combined with increased GABA(A) receptor levels in various CNS regions. The alterations in GLT-1 variants and the ionotropic receptors are consistent with an increased level of extracellular glutamate. The interaction between environmental toxicity and genetic susceptibility was also tested using mice expressing various Apolipoprotein E (ApoE) genotypes. Mice lacking the ApoE gene showed relative resistance to cycad-induced toxicity as measured by GLT-1B labeling, but all mice expressing the human ApoE isoforms showed a similar loss of GLT-1B. We have further shown that an isolated cycad toxin (beta-sitosterol-beta-d-glucoside, BSSG), previously shown to release glutamate in vitro [Wilson, J.M., Khabazian, I., Wong, M.C., Seyedalikhani, A., Bains, J.S., Pasqualotto, B.A., Williams, D.E., Andersen, R.J., Simpson, R.J., Smith, R., Craig, U.K., Kurland, L.T., Shaw, C.A., 2002. Behavioral and neurological correlates of ALS-parkinsonism dementia complex in adult mice fed washed cycad flour. Neuromol. Med. 1 (3), 207-221], can be directly toxic to motor neurons in vivo [Wilson, J.M., Petrik, M.S., Moghadasian, M.H., Shaw, C.A., 2005. Examining the interaction of apo E and neurotoxicity on a murine model of ALS-PDC. Can. J. Physiol. Pharmacol. 83 (2), 131-141]. However, BSSG-fed mice did not show altered GLT-1B labeling in the spinal cord suggesting that an initial excitotoxic mechanism may not be responsible for the final neuronal loss observed. While glutamate-mediated excitotoxicity is likely involved in the outcomes following cycad/BSSG exposure, the precise location in the cascade of events ultimately leading to neuronal death remains to be determined.