Review of codelists used to define hypertension in electronic health records and development of a codelist for research.

BACKGROUND AND AIMS: Hypertension is a leading risk factor for cardiovascular disease. Electronic health records (EHRs) are routinely collected throughout a person's care, recording all aspects of health status, including current and past conditions, prescriptions and test results. EHRs can be used for epidemiological research. However, there are nuances in the way conditions are recorded using clinical coding; it is important to understand the methods which have been applied to define exposures, covariates and outcomes to enable interpretation of study findings. This study aimed to identify codelists used to define hypertension in studies that use EHRs and generate recommended codelists to support reproducibility and consistency. ELIGIBILITY CRITERIA: Studies included populations with hypertension defined within an EHR between January 2010 and August 2023 and were systematically identified using MEDLINE and Embase. A summary of the most frequently used sources and codes is described. Due to an absence of Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) codelists in the literature, a recommended SNOMED CT codelist was developed to aid consistency and standardisation of hypertension research using EHRs. FINDINGS: 375 manuscripts met the study criteria and were eligible for inclusion, and 112 (29.9%) reported codelists. The International Classification of Diseases (ICD) was the most frequently used clinical terminology, 59 manuscripts provided ICD 9 codelists (53%) and 58 included ICD 10 codelists (52%). Informed by commonly used ICD and Read codes, usage recommendations were made. We derived SNOMED CT codelists informed by National Institute for Health and Care Excellence guidelines for hypertension management. It is recommended that these codelists be used to identify hypertension in EHRs using SNOMED CT codes. CONCLUSIONS: Less than one-third of hypertension studies using EHRs included their codelists. Transparent methodology for codelist creation is essential for replication and will aid interpretation of study findings. We created SNOMED CT codelists to support and standardise hypertension definitions in EHR studies.

Determining prescriptions in electronic healthcare record data: methods for development of standardized, reproducible drug codelists.

Objective: To develop a standardizable, reproducible method for creating drug codelists that incorporates clinical expertise and is adaptable to other studies and databases. Materials and Methods: We developed methods to generate drug codelists and tested this using the Clinical Practice Research Datalink (CPRD) Aurum database, accounting for missing data in the database. We generated codelists for: (1) cardiovascular disease and (2) inhaled Chronic Obstructive Pulmonary Disease (COPD) therapies, applying them to a sample cohort of 335 931 COPD patients. We compared searching all drug dictionary variables (A) against searching only (B) chemical or (C) ontological variables. Results: In Search A, we identified 165 150 patients prescribed cardiovascular drugs (49.2% of cohort), and 317 963 prescribed COPD inhalers (94.7% of cohort). Evaluating output per search strategy, Search C missed numerous prescriptions, including vasodilator anti-hypertensives (A and B:19 696 prescriptions; C:1145) and SAMA inhalers (A and B:35 310; C:564). Discussion: We recommend the full search (A) for comprehensiveness. There are special considerations when generating adaptable and generalizable drug codelists, including fluctuating status, cohort-specific drug indications, underlying hierarchical ontology, and statistical analyses. Conclusions: Methods must have end-to-end clinical input, and be standardizable, reproducible, and understandable to all researchers across data contexts.

Prevalence of Chronic Obstructive Pulmonary Disease in England from 2000 to 2019.

Background: There is considerable variation in reported chronic obstructive pulmonary disease (COPD) prevalence internationally, partly due to differing definitions in use. Accurate estimates of disease prevalence are important for allocation of health-care resources, yet UK estimates of COPD prevalence have not been updated for a decade. We calculated yearly COPD prevalence in England between 2000 and 2019 using different definitions of COPD. Methods: We used routinely collected primary care electronic healthcare record (EHR) data from the Clinical Practice Research Datalink (CPRD) Aurum database linked with secondary care data from the Hospital Episode Statistics (HES) Admitted Patient Care (APC) database. Mid-year point prevalence was calculated yearly from 2000 to 2019 in English adults aged ≥40 years using 5 definitions: (i) validated COPD, (ii) Quality and Outcomes Framework (QOF) COPD, (iii) COPD symptoms, inhaler prescription, and no asthma diagnosis, (iv) hospitalisation with COPD as any diagnosis, (v) hospitalisation with COPD as primary or secondary diagnosis. Prevalence was further stratified by gender, age group, and region. Results: A total of 12,745,793 people were included over the 20-year period. Annual cohort sizes ranged from 4,373,538 in 2000 to 6,159,496 in 2019. Estimates of COPD prevalence increased every year from 2000 and the difference in estimated prevalence between the validated and QOF definitions has grown over time. In 2019, a COPD prevalence of 4.9% was found using validated events in either primary or secondary care (definition 1 or definition 5). Additionally, including potentially undiagnosed cases (definition 3) in the COPD definition produced an increased prevalence of 6.7%. Conclusion: Common definitions of COPD (eg, QOF codes), may underestimate the true prevalence. The extent of this underestimate has increased over time and could lead to under-allocation of resources where need is estimated based on these definitions. Standardisation of COPD coding in routine EHRs and metrics such as spirometry is key to accurate disease monitoring.

Comparison of COPD primary care in England, Scotland, Wales, and Northern Ireland.

Currently the National Asthma and COPD audit programme (NACAP) only undertakes audit of COPD primary care in Wales due to its near complete data coverage. We aimed to determine if the quality of COPD primary care in the other UK nations is comparable with Wales. We found that English, Scottish, and Northern Irish practices were significantly worse than Welsh practices at recording coded lung function parameters used in COPD diagnosis (ORs: 0.51 [0.43-0.59], 0.29 [0.23-0.36], 0.42 [0.31-0.58], respectively) and referring appropriate patients for pulmonary rehabilitation (ORs: 0.10 [0.09-0.11], 0.12 [0.11-0.14], 0.22 [0.19-0.25], respectively). Completing national audits of primary care in Wales only may have led to improvements in care, or at least improvements in the recording of care in Wales that are not occurring elsewhere in the UK. This highlights the potential importance of audit in improving care quality and accurate recording of that care.

"NEWS2" as an Objective Assessment of Hospitalised COPD Exacerbation Severity.

Introduction: There is currently no accepted way to risk-stratify hospitalised exacerbations of chronic obstructive pulmonary disease (COPD). We hypothesised that the revised UK National Early Warning Score (NEWS2) calculated at admission would predict inpatient mortality, need for non-invasive ventilation (NIV) and length-of-stay. Methods: We included data from 52,284 admissions for exacerbation of COPD. Data were divided into development and validation cohorts. Logistic regression was used to examine relationships between admission NEWS2 and outcome measures. Predictive ability of NEWS2 was assessed using area under receiver operating characteristic curves (AUC). We assessed the benefit of including other baseline data in the prediction models and assessed whether these variables themselves predicted admission NEWS2. Results: 53% of admissions had low risk, 24% medium risk and 23% a high risk NEWS2 in the development cohort. The proportions dying as an inpatient were 2.2%, 3.6% and 6.5% by NEWS2 risk category, respectively. The proportions needing NIV were 4.4%, 9.2% and 18.0%, respectively. NEWS2 was poorly predictive of length-of-stay (AUC: 0.59[0.57-0.61]). In the external validation cohort, the AUC (95% CI) for NEWS2 to predict inpatient death and need for NIV were 0.72 (0.68-0.77) and 0.70 (0.67-0.73). Inclusion of patient demographic factors, co-morbidity and COPD severity improved model performance. However, only 1.34% of the variation in admission NEWS2 was explained by these baseline variables. Conclusion: The generic NEWS2 risk assessment tool, readily calculated from simple physiological data, predicts inpatient mortality and need for NIV (but not length-of-stay) at exacerbations of COPD. NEWS2 therefore provides a classification of hospitalised COPD exacerbation severity.

Deriving a Standardised Recommended Respiratory Disease Codelist Repository for Future Research.

BACKGROUND: Electronic health record (EHR) databases provide rich, longitudinal data on interactions with healthcare providers and can be used to advance research into respiratory conditions. However, since these data are primarily collected to support health care delivery, clinical coding can be inconsistent, resulting in inherent challenges in using these data for research purposes. METHODS: We systematically searched existing international literature and UK code repositories to find respiratory disease codelists for asthma from January 2018, and chronic obstructive pulmonary disease and respiratory tract infections from January 2020, based on prior searches. Medline searches using key terms provided in article lists. Full-text articles, supplementary files, and reference lists were examined for codelists, and codelists repositories were searched. A reproducible methodology for codelists creation was developed with recommended lists for each disease created based on multidisciplinary expert opinion and previously published literature. RESULTS: Medline searches returned 1126 asthma articles, 70 COPD articles, and 90 respiratory infection articles, with 3%, 22% and 5% including codelists, respectively. Repository searching returned 12 asthma, 23 COPD, and 64 respiratory infection codelists. We have systematically compiled respiratory disease codelists and from these derived recommended lists for use by researchers to find the most up-to-date and relevant respiratory disease codelists that can be tailored to individual research questions. CONCLUSION: Few published papers include codelists, and where published diverse codelists were used, even when answering similar research questions. Whilst some advances have been made, greater consistency and transparency across studies using routine data to study respiratory diseases are needed.

Does pay-for-performance improve patient outcomes in acute exacerbation of COPD admissions?

BACKGROUND: The COPD Best Practice Tariff (BPT) is a pay-for-performance scheme in England that incentivises review by a respiratory specialist within 24 hours of admission and completion of a list of key care components prior to discharge, known as a discharge bundle, for patients admitted with acute exacerbation of COPD (AECOPD). We investigated whether the two components of the COPD BPT were associated with lower 30-day mortality and readmission in people discharged following AECOPD. METHODS: Longitudinal study of national audit data containing details of AECOPD admissions in England and Wales between 01 February 2017 and 13 September 2017. Data were linked with national admissions and mortality data. Mixed-effects logistic regression, using a random intercept for hospital to adjust for clustering of patients, was used to determine the relationship between the COPD BPT criteria (combined and separately) and 30-day mortality and readmission. Models were adjusted for age, sex, socioeconomic status, length of stay, smoking status, Charlson comorbidity index, mental illness and requirement for oxygen or noninvasive ventilation during admission. RESULTS: 28 345 patients discharged from hospital following AECOPD were included. 37% of admissions conformed to the two COPD BPT criteria. No relationship was observed between BPT conforming admissions and 30-day mortality (OR: 1.09 (95% CI 0.92 to 1.29)) or readmissions (OR: 0.96 (95% CI 0.90 to 1.02)). No relationship was observed between either of the individual COPD BPT components and 30-day mortality or readmissions. However, a specialist review at any time during admission was associated with lower inpatient mortality (OR: 0.69 (95% CI 0.58 to 0.81)). CONCLUSION: Completion of the combined COPD BPT criteria does not appear associated with a reduction in 30-day mortality or readmission. However, specialist review was associated with reduced inpatient mortality. While it is difficult to argue that discharge bundles do not improve care, this analysis questions whether the pay-for-performance model improves mortality or readmissions.

Predictors of pulmonary rehabilitation completion in the UK.

INTRODUCTION: Pulmonary rehabilitation has been shown to improve dyspnoea, fatigue, quality of life and exercise capacity in individuals with chronic obstructive pulmonary disease (COPD). Our aim was to determine the characteristics of people with COPD associated with completion of pulmonary rehabilitation. METHODS: This was a cross-sectional analysis of 7060 people with COPD enrolled in pulmonary rehabilitation between January 1, 2017 and March 31, 2017. Data were from a UK national audit of COPD care. Factors associated with pulmonary rehabilitation completion were determined using mixed effects logistic regression with a random intercept for pulmonary rehabilitation service. Factors chosen for assessment based on clinical judgement and data availability were age, sex, country, socioeconomic status, body mass index, referral location, programme type, start within 90 days, smoking status, oxygen therapy, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, Medical Research Council (MRC) dyspnoea grade, any exercise test and any health status questionnaire. RESULTS: 4635 (66%) people with COPD completed a pulmonary rehabilitation programme. People that were aged ≥60 years, resident in Wales, referred within 90 days, an ex- or never-smoker, received an exercise test, or received a health status questionnaire had significantly greater odds of completing pulmonary rehabilitation. People that were in the most deprived quintile, underweight or very severely obese, enrolled in a rolling rather than a cohort programme, had a higher GOLD stage and had a higher MRC grade had significantly lower odds of completing pulmonary rehabilitation. CONCLUSIONS: People with COPD were more likely to complete pulmonary rehabilitation when best practice guidelines were followed. People with more severe COPD symptoms and those enrolled in rolling rather than cohort programmes were less likely to complete pulmonary rehabilitation. Referring people with COPD in the earlier stages of disease, ensuring programmes follow best practice guidelines and favouring cohort over rolling programmes could improve rates of pulmonary rehabilitation completion.

Predictors of Referral to Pulmonary Rehabilitation from UK Primary Care.

Background: A large proportion of people with COPD are not referred to pulmonary rehabilitation (PR) despite its proven benefits. No previous studies have examined predictors of referral to PR. Objective: To determine the characteristics of people with COPD associated with referral to PR. Methods: Cross-sectional analysis of a primary care cohort of 82,696 Welsh people with COPD generated as part of a UK national audit of COPD care. Data represent care received by patients as of 31/03/2017. Referral to PR was defined as any code in the patient record indicating referral to PR in the last 3 years. Potential predictors of referral to PR were chosen based on clinical judgement and data availability. Independent predictors of PR referral were determined using backward stepwise mixed-effects logistic regression with a random effect for practice. Variables assessed were: age, gender, deprivation, MRC recorded in past year, MRC grade, smoking status recorded in past year, smoking status, number of exacerbations in past year, inhaled therapy prescription, influenza vaccination, and comorbidities of diabetes, hypertension, coronary heart disease, stroke, heart failure, lung cancer, asthma, bronchiectasis, depression, anxiety, severe mental illness, osteoporosis, and painful condition. Results: A total of 13,297 people (16%) with COPD were referred from primary care for PR. Patients with a comorbidity of bronchiectasis or depression, MRC recorded in the last year, higher MRC grade, more exacerbations in the last year, a greater level of inhaled therapy, an influenza vaccination, or were an ex-smoker had significantly higher odds of referral to PR. Patients that were older, female, more deprived, or had a comorbidity of diabetes, asthma, or painful condition had significantly lower odds of referral to PR. Conclusion: Generally appropriate patients are being prioritised for PR referral; however, it is concerning that women, current smokers, and more deprived patients appear to have lower odds of referral.

Validation of acute exacerbation of chronic obstructive pulmonary disease (COPD) recording in electronic health records: a systematic review protocol.

INTRODUCTION: Many patients with chronic obstructive pulmonary disease (COPD) experience a sustained worsening in symptoms termed an acute exacerbation (AECOPD). AECOPDs impact on patients' quality of life and lung function, are costly to health services and are an important topic for research. Electronic health records (EHR) are increasingly being used to study AECOPD, requiring accurate detection of AECOPD in EHRs to ensure generalisable results. The aim of this protocol is to provide an overview of studies that validate AECOPD definitions used in EHRs and administrative claims databases. METHODS AND ANALYSIS: Medline and Embase will be searched for terms related to COPD exacerbation, EHRs and validation. All studies published between 1 January 1990 and 30 September 2019 written in English that validate AECOPD in EHRs and administrative claims databases will be considered. INCLUSION CRITERIA: EHR data must be routinely collected; the AECOPD detection algorithm must be compared against a reference standard; and a measure of validity must be calculable. Two independent reviewers will screen articles for inclusion, extract study details and assess risk of bias using QUADAS-2. Disagreements will be resolved by consensus or arbitration by a third reviewer. This protocol has been developed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols checklist. ETHICS AND DISSEMINATION: This will be a review of previously published literature therefore no ethical approval is required. Results from this review will be published in a peer-reviewed journal. The results can be used in future research to identify occurrences of AECOPD. PROSPERO REGISTRATION NUMBER: CRD42019130863.

Code sets for respiratory symptoms in electronic health records research: a systematic review protocol.

INTRODUCTION: Asthma and chronic obstructive pulmonary disease (COPD) are common respiratory conditions, which result in significant morbidity worldwide. These conditions are associated with a range of non-specific symptoms, which in themselves are a target for health research. Such research is increasingly being conducted using electronic health records (EHRs), but computable phenotype definitions, in the form of code sets or code lists, are required to extract structured data from these large routine databases in a systematic and reproducible way. The aim of this protocol is to specify a systematic review to identify code sets for respiratory symptoms in EHRs research. METHODS AND ANALYSIS: MEDLINE and Embase databases will be searched using terms relating to EHRs, respiratory symptoms and use of code sets. The search will cover all English-language studies in these databases between January 1990 and December 2017. Two reviewers will independently screen identified studies for inclusion, and key data will be extracted into a uniform table, facilitating cross-comparison of codes used. Disagreements between the reviewers will be adjudicated by a third reviewer. This protocol has been produced in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines. ETHICS AND DISSEMINATION: As a review of previously published studies, no ethical approval is required. The results of this review will be submitted to a peer-reviewed journal for publication and can be used in future research into respiratory symptoms that uses electronic healthcare databases. PROSPERO REGISTRATION NUMBER: CRD42018100830.

Moderate-dose sedation and analgesia during targeted temperature management after cardiac arrest.

BACKGROUND: Sedation and analgesia regimens during targeted temperature management (TTM), after cardiac arrest varies widely, are poorly described in the literature and may have a negative impact on outcome. Since implementing TTM in 2005, we have used moderate-dose sedation and describe our experience with this approach. METHODS: In this retrospective review, we included patients treated with TTM for cardiac arrest at our institution for 2008-2012. Patients received TTM if they did not follow verbal commands following cardiac arrest, regardless of place of arrest or rhythm. Utstein-compatible data were prospectively entered into the International Cardiac Arrest Registry, supplemented by review of nursing, pharmacy, and physical therapy records. We report analgesic and sedative medications and doses during the 24 h of active TTM at 33 °C, resource utilization, and important clinical events. RESULTS: 166 patients treated with TTM after in- and out-of-hospital cardiac arrest with complete data were included. Overall survival was 42 %, median time to following commands was 3 h after rewarming (-6, 14), time to spontaneous breathing trial was 19 h (5-35), time to extubation was 28 h (9-60), and 59 % of survivors were discharged directly home at 13 (10-20) days. The incidence of seizure was 6 %, septic shock 4 %, and pneumonia 32 %. Four survivors required tracheostomy at 8, 8, 12, and 16 days. CONCLUSIONS: A moderate-dose sedation and analgesia regimen was well tolerated and effective during therapeutic hypothermia after cardiac arrest and is an effective alternative to very deep sedation. We recommend more complete description of sedation and analgesia protocols in future studies, including expanded outcome reporting to include variables affected by sedation therapy. Further study is required to define which sedation approach for TTM may be best.

Feasibility of bispectral index monitoring to guide early post-resuscitation cardiac arrest triage.

INTRODUCTION: Triage after resuscitation from cardiac arrest is hindered by reliable early estimation of brain injury. We evaluated the performance of a triage model based on early bispectral index (BIS) findings and cardiac risk classes. METHODS: Retrospective evaluation of serial patients resuscitated from cardiac arrest, unable to follow commands, and undergoing hypothermia. Patients were assigned to a cardiac risk group: STEMI, VT/VF shock, VT/VF no shock, or PEA/asystole, and to a neurological dysfunction group, based on the BIS score following first neuromuscular blockade (BISi), and classified as BISi>20, BISi 10-20, or BISi<10. Cause of death was described as neurological or circulatory. RESULTS: BISi in 171 patients was measured at 267(±177)min after resuscitation and 35(±1.7)°C. BISi<10 suffered 82% neurological-cause and 91% overall mortality, BISi 10-20 35% neurological and 55% overall mortality, and BISi>20 12% neurological and 36% overall mortality. 33 patients presented with STEMI, 15 VT/VF-shock, 41 VT/VF-no shock, and 80 PEA/asystole. Among BISi>20 patients, 75% with STEMI underwent urgent cardiac catheterization (cath) and 94% had good outcome. When BISi>20 with VT/VF and shock, urgent cath was infrequent (33%), and 4 deaths (44%) were uniformly of circulatory etiology. Of 56 VT/VF patients without STEMI, 24 were BISi>20 but did not undergo urgent cath - 5(20.8%) of these had circulatory-etiology death. Circulatory-etiology death also occurred in 26.5% BIS>20 patients with PEA/asystole. When BISi<10, a neurological etiology death dominated independent of cardiac risk group. CONCLUSIONS: Neurocardiac triage based on very early processed EEG (BIS) is feasible, and may identify patients appropriate for individualized post-resuscitation care. This and other triage models warrant further study.

Initial bispectral index may identify patients who will awaken during therapeutic hypothermia after cardiac arrest: a retrospective pilot study.

AIM: Patients sustain a range of neurologic injuries after cardiac arrest, and determining which patients should be treated with therapeutic hypothermia (TH) is complex, often confounded by sedation and neuromuscular blockade (NMB). We evaluated bispectral index (BIS) monitoring as a tool to identify adult patients that awakened during therapeutic hypothermia. METHODS: Review of prospectively collected registry data, with retrospective chart review of patient descriptions during hypothermia. Data are presented as median (interquartile range). RESULTS: 7 of 309 patients (2.2%) treated with TH over 6 years awoke (followed commands) prior to completing hypothermia. Median age was 58 (54-66) years; 71% were male, cardiac arrest was witnessed in 6 (86%) and out-of-hospital in 6 (86%), and 4 patients (57%) were transferred from another hospital. 5 patients (71%) had an initial rhythm of ventricular tachycardia or fibrillation, time to return of spontaneous circulation was 17 (12-23)min. The BIS value after first NMB dose during TH was 63, 45, 43, 52, 62, 54, and 42 (median 52, IQR 44-58, 95% confidence interval 46-58). The median BIS value in the remaining data set (n=302) was 18 (6-36), p<0.001, and only 6% of BIS1 values were >46. CONCLUSION: Patients who awakened early had higher BIS values after the first dose of NMB. Processed EEG values after cardiac arrest may provide additional information that could assist with determining best treatment.

Transgenic expression of an altered angiotensin type I AT1 receptor resulting in marked modulation of vascular type I collagen.

The angiotensin II (AngII) type I receptor (AT1) was modified by replacing its third intracellular loop and C-terminal tail with the corresponding regions from the bradykinin B2 receptor. Transgenic mice were produced that overexpress this mutated receptor (AB3T). Considerably less collagen content in the intact aorta and in primary aortic smooth muscle cells (aSMCs) cultures was observed in the transgenic mice. On the other hand, elastin content remained unchanged as measured by Western blot, and insoluble amino acid quantitation. The contraction of isolated aortas also remained unaltered. The aSMCs derived from the transgenic mice showed a reduction in AngII responsive type I collagen production. In aSMCs from transgenic mice, the cascade of Akt to the mammalian target rapamycin (mTOR) to p70 S6 kinase (p70S6K) was not AngII activated, while in the aSMCs from wild-type (WT) mice the cascade was AngII activated. Angiotensin activation of Smad2 and Stat3 was also reduced in the AB3T aSMCs. However, no change in the effect of transforming growth factor ß (TGFß) on type I collagen production was observed. Also, the activation of ERK and JNK and G-protein linked signaling remained unaltered in response to AngII. Akt and PI3K activation inhibitors blocked AngII-stimulated type I collagen expression in WT aSMCs, whereas ERK inhibitor had no such effect. Our results point to an Akt/mTOR/p70S6K regulation of collagen production by AngII with participation of Smad2 and Stat3 cascades in this process.

Stratigraphy of the Anthropocene.

The Anthropocene, an informal term used to signal the impact of collective human activity on biological, physical and chemical processes on the Earth system, is assessed using stratigraphic criteria. It is complex in time, space and process, and may be considered in terms of the scale, relative timing, duration and novelty of its various phenomena. The lithostratigraphic signal includes both direct components, such as urban constructions and man-made deposits, and indirect ones, such as sediment flux changes. Already widespread, these are producing a significant 'event layer', locally with considerable long-term preservation potential. Chemostratigraphic signals include new organic compounds, but are likely to be dominated by the effects of CO(2) release, particularly via acidification in the marine realm, and man-made radionuclides. The sequence stratigraphic signal is negligible to date, but may become geologically significant over centennial/millennial time scales. The rapidly growing biostratigraphic signal includes geologically novel aspects (the scale of globally transferred species) and geologically will have permanent effects.

Circulating galectin-3 promotes metastasis by modifying MUC1 localization on cancer cell surface.

Adhesion of circulating tumor cells to the blood vessel endothelium is a critical step in cancer metastasis. We show in this study that galectin-3, the concentration of which is greatly increased in the circulation of cancer patients, increases cancer cell adhesion to macrovascular and microvascular endothelial cells under static and flow conditions, increases transendothelial invasion, and decreases the latency of experimental metastasis in athymic mice. These effects of galectin-3 are shown to be a consequence of its interaction with cancer-associated MUC1, which breaks the "protective shield" of the cell-surface MUC1 by causing MUC1 polarization, leading to exposure of smaller cell-surface adhesion molecules/ligands including CD44 and ligand(s) for E-selectin. Thus, the interaction in the bloodstream of cancer patients between circulating galectin-3 and cancer cells expressing MUC1 bearing the galectin-3 ligand TF (Galbeta1,3GalNAc-) promotes metastasis. This provides insight into the molecular regulation of metastasis and has important implications for the development of novel therapeutic strategies for prevention of metastasis.

Identification of a phenotypically and functionally distinct population of long-lived neutrophils in a model of reverse endothelial migration.

Recent studies have demonstrated that neutrophils are not a homogenous population of cells. Here, we have identified a subset of human neutrophils with a distinct profile of cell-surface receptors [CD54(high), CXC chemokine receptor 1(low) (CXCR1(low))], which represent cells that have migrated through an endothelial monolayer and then re-emerged by reverse transmigration (RT). RT neutrophils, when in contact with endothelium, were rescued from apoptosis, demonstrate functional priming, and were rheologically distinct from neutrophils that had not undergone transendothelial migration. In vivo, 1-2% of peripheral blood neutrophils in patients with systemic inflammation exhibit a RT phenotype. A smaller population existed in healthy donors ( approximately 0.25%). RT neutrophils were distinct from naïve circulatory neutrophils (CD54(low), CXCR1(high)) and naïve cells after activation with formyl-Met-Leu-Phe (CD54(low), CXCR1(low)). It is important that the RT phenotype (CD54(high), CXCR1(low)) is also distinct from tissue-resident neutrophils (CD54(low), CXCR1(low)). Our results demonstrate that neutrophils can migrate in a retrograde direction across endothelial cells and suggest that a population of tissue-experienced neutrophils with a distinct phenotype and function are present in the peripheral circulation in humans in vivo.

Differing mechanisms of leukocyte recruitment and sensitivity to conditioning by shear stress for endothelial cells treated with tumour necrosis factor-alpha or interleukin-1beta.

The cytokines tumour necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1B) induce endothelial cells to recruit leukocytes. However, the exact adhesion and activation mechanisms induced by each cytokine, and their relative sensitivities to modulation by endothelial exposure to shear stress remain unclear. We cultured human umbilical vein endothelial cells (HUVEC) in glass capillaries at various shear stresses, with TNFalpha or IL-1B added for the last 4 h. Subsequently, human neutrophils were perfused over the HUVEC, and adhesion and migration were recorded. Both cytokines induced dose-dependent capture of neutrophils. However, while conditioning of HUVEC by increasing shear stress for 24 h diminished their response to TNFalpha, the response of HUVEC to IL-1B was similar at all shear stresses. The differing sensitivities were evident at levels of adhesive function and mRNA for adhesion molecules and chemokines. Analysis of nuclear factor kappaB (NF-kappaB)/Rel family of transcription factors showed that their expression and activation were modified by exposure to shear stress, but did not obviously explain differential responses to TNFalpha and IL-1B. Antibodies against selectins were effective against capture of neutrophils on TNFalpha-treated but not IL-1B-treated HUVEC. Stable adhesion was supported by beta2-integrins in each case. Activation of neutrophils occurred dominantly through CXC-chemokine receptor 2 (CXCR2) for TNFalpha-treated HUVEC, while blockade of CXCR1, CXCR2 and of platelet-activating factor receptors caused additive inhibition of migration on IL-1B-treated HUVEC. The mechanisms which underlie neutrophil recruitment, and their modulation by the haemodynamic environment, differ between cytokines. Interventions aimed against leukocyte recruitment may not operate equally in different inflammatory milieu.