Cost-effectiveness of Resonance® metallic ureteral stent compared with standard polyurethane ureteral stents in malignant ureteric obstruction: A cost-utility analysis.

Background: Malignant ureteral obstruction (MUO) is a frequent challenge for urologists. Patients have poor prognoses, treatment aims to improve quality-of-life while optimising renal function. Standard practice in the United Kingdom is to use polyurethane stents, which require frequent surgical replacements for blockages and encrustation. More durable metallic stents are available, although these incur an increased initial purchase price. Aims: We aim to assess whether the use of polyurethane double-J (JJ) or metallic stent, Resonance® is more cost-effective for managing MUO in the UK healthcare setting. Methods: A Markov model was parameterised to 5 years with costs and health-related quality-of-life consequences for treating MUO with Resonance metallic stent (Cook Medical), versus standard JJ stents, from the UK care system perspective, with 3.5% discounting. Deterministic and probabilistic sensitivity analyses were undertaken to assess the effect of uncertainty. Results: Over 5 years, approximately four fewer repeat surgical interventions were estimated in the metallic stent arm compared with the JJ stent, driving a 23.4% reduction in costs. The mean estimates of costs and benefits indicate that treatment of MUO with Resonance for 5 years is dominant over JJ stents. Over 5 years a cost-saving of £2164.74 and a health gain of +0.046 quality-adjusted life years (QALYs) per patient is estimated. With a maximum willingness to pay of £20 k per QALY, a net monetary benefit (NMB) of £3077.83 is estimated. Probabilistic sensitivity analysis at a willingness to pay threshold of £20 000 indicates an 89.3% probability of Resonance being cost-effective over JJ stents. Within 1-year savings of £726.53 are estimated driven by a reduction of two fewer repeat surgical interventions when using the metallic stent. Conclusions: Resonance metallic stents for the treatment of MUO reduce the number of repeat procedures and could be a cost-effective option for the treatment, potentially offering efficiencies to the healthcare system.

The International Working Group on New Developments in Pharmacovigilance: Advancing Methods and Communication in Pharmacovigilance.

PURPOSE: In 2019, the International Working Group (IWG), focusing on New Developments in Pharmacovigilance, was established. This group is coordinated by the Drug Safety Research Unit in the United Kingdom, and the mission of the IWG is to progress pharmacovigilance methodologies and promote the safe and effective use of medicines and vaccines, thereby further protecting patients. Novel therapeutics are continuously being developed to alleviate medical conditions, but with advancing technologies, innovative pharmacovigilance methodologies need to be developed to effectively monitor the use and safety of these products. With reduced timelines proposed for premarketing clinical trials and increased application of real-world evidence supporting regulatory approvals, products may be used in real-world clinical practice in shorter timeframes than before. Therefore, the need for effective methods of monitoring medicines and collecting safety data in real-time is of paramount importance to public health. METHODS: The IWG aims to advance existing methodologies used in the detection, monitoring, and analysis of safety data in pharmacovigilance and to communicate best practice proposals to support decision making in health care. The IWG will identify areas requiring review of current processes or methodologic research and will communicate the output of the IWG through peer-reviewed publications, reports, and presentation of findings at relevant conferences and scientific meetings. FINDINGS: The IWG is currently reviewing two areas in pharmacovigilance; case-level causality assessment and the strengths and limitations of data sources. The IWG is advancing these areas by producing two scoping reviews which will be easily accessible to regulatory agencies, industry, academia, and interested persons or organizations. IMPLICATIONS: The scoping reviews comply with the IWGs mission to progress pharmacovigilance methodologies and promote the safe and effective use of medicines and vaccines. The present article shares details of the objectives of the IWG and provides an overview on the status of IWG activities.

What Residents Want: Perceptions of Learning During a Pediatrics Night Float Rotation.

OBJECTIVE: Most efforts to improve the educational value of night shifts focus on delivering content through structured sessions. Less is known about aligning curricular efforts with inherent nighttime learning. This study explored interns' nighttime experiences to better understand how learning works for the purpose of designing a curriculum to best support interns' learning at night. METHODS: The authors employed a constructivist grounded theory approach. They conducted semistructured interviews with 12 Family Medicine and Pediatric interns recruited during their first-night float rotation at a tertiary care children's hospital between February 2020 and August 2021. Interviews elicited stories about nighttime experiences on the basis of a modified critical incident technique. Four authors used an inductive approach to data analysis and codebook development, then all authors participated in a thematic review. RESULTS: The authors identified distinctions between interns' perceptions of teaching and learning, with participants reporting rich instances of experiential learning at night. The authors discovered that interns do not want a didactic teaching curriculum at night. Rather, they want support to optimize workplace learning: the opportunity to independently initiate patient assessments, informal teaching arising from patient care, reassurance that support from supervisors is readily available, orientation to resources, and feedback. CONCLUSIONS: Findings suggest informal workplace learning is already occurring at night and historical attempts to implement formal curricula may have a low return on investment. A curricular frameshift is recommended to support learning at night that emphasizes informal teaching responsive to learning needs that arise from patient care, integrating but not emphasizing formal didactics when necessary.

Cost-Effectiveness of PHMB & betaine wound bed preparation compared with standard care in venous leg ulcers: A cost-utility analysis in the United Kingdom.

BACKGROUND: Wounds cost £8.3 billion per year in the United Kingdom (UK) annually. Venous leg ulcers (VLUs) account for 15% of wounds and can be complicated to heal, increasing nurse visits and resource costs. Recent wound bed preparation consensus recommends wound cleansing and biofilm disrupting agents. However, inert cleansers such as tap water or saline are inexpensive, an evaluation of evidence is required to justify the higher upfront costs of treatment with active cleansers. We undertook a cost-effectiveness analysis of the use of a biofilm disrupting and cleansing solution and gel, Prontosan® Solution and Gel X, (PSGX) (B Braun Medical), as compared to the standard practice of using saline solution, for treating VLUs. METHODS: A Markov model was parameterised to one-year costs and health-related quality of life consequences of treating chronic VLUs with PSGX versus saline solution. Costs are viewed from a UK healthcare payer perspective, include routine care and management of complications. A systematic literature search was performed to inform the clinical parameters of the economic model. Deterministic univariate sensitivity analysis (DSA) and probabilistic sensitivity analysis (PSA) were undertaken. RESULTS: For PSGX an Incremental Net Monetary Benefit (INMB) of £1,129.65 to £1,042.39 per patient (with a Maximum Willingness to Pay of £30k and £20k per QALY respectively), of which cost savings are £867.87 and 0.0087 quality-adjusted life years (QALYs) gain per patient. PSA indicates a 99.3% probability of PSGX being cost-effective over saline. CONCLUSIONS: PSGX for the treatment of VLUs is dominant compared with saline solution in the UK with expected cost-savings within a year and improved patient outcomes.

Nurses' Perceptions of Barriers to Out-of-Bed Activities Among Patients Receiving Mechanical Ventilation.

BACKGROUND: Delays in early patient mobility are common in critical care areas. Oral intubation with mechanical ventilation is negatively associated with out-of-bed activities. OBJECTIVES: To explore nurses' mobility practices for patients with oral intubation and mechanical ventilation and identify barriers related to patient, nurse, and environment-of-care factors specific to this population. METHODS: In this cross-sectional, descriptive study in a medical intensive care unit, mobility was defined as standing, sitting in a chair, or walking. A total of 105 patients who met predefined mobility criteria and their 48 nurses were enrolled. Nurses were interviewed about mobility practices at the ends of shifts. Descriptive statistics summarized nurse and patient characteristics and mobility barriers. RESULTS: Patients were deemed ready to begin mobility within a mean (SD) of 41.5 (34.8) hours after oral endotracheal intubation. Two-thirds of nurses reported that they never or rarely got these patients out of bed. Only 12.4% of patients had a clinician's activity order. Common patient-related barriers were uncooperative behavior (21.9%) and active medical issues (15%), even in patients who met mobility criteria. Nurse-related barriers were concerns for patient safety, specifically falls (14.3% of patients) and harm (9.5%). The environment of care posed very few barriers; nurses rarely mentioned that lack of help (13.3% of patients) or lack of clinician's activity order (5.7%) impeded mobility. CONCLUSIONS: Mobility practices were nonexistent in these patients despite patients' being deemed ready to begin out-of-bed activities. Nurses must be attentive to their unit's mobility culture to overcome these barriers.

Wound bed preparation: a case series using polyhexanide and betaine solution and gel-a UK perspective.

OBJECTIVE: The burden of wound care within the NHS is estimated at a cost of £5.3 billion per year and is set to rise annually by 30%. This case series describes the results of using polyhexanide (PHMB) and betaine wound irrigation solution and gels (Prontosan, B.Braun Medical Ltd., UK) across the UK in hard-to-heal (also described as chronic) wounds up to 20 years' duration, with an observation period of greater than one month. Over half of the hard-to-heal wounds were healed and vast improvements to all other wounds were observed. Improvements to wound bed condition were reported as early as two days after commencing initial treatment, with decreases in malodour, exudate, slough and pain reported across the case series. In addition to wound bed improvements, a reduction in dressing change frequency of 55% was observed in hard-to-heal wounds under the new treatment regime.

Particulate matter and the airway epithelium: the special case of the underground?

Airborne particulate matter (PM) is a leading driver of premature mortality and cardiopulmonary morbidity, associated with exacerbations of asthma and chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung cancer. The airway epithelium, as the principal site of PM deposition, is critical to the effects of, and initial response to, PM. A key mechanism by which PM exerts its effects is the generation of reactive oxygen species (ROS), inducing antioxidant and inflammatory responses in exposed epithelial cells. However, much of what is known about the effects of PM is based on research using particulates from urban air. PM from underground railways is compositionally highly distinct from urban PM, being rich in metals associated with wheel, rail and brake wear and electrical arcing and component wear, which endows underground PM with potent ROS-generating capacity. In addition, underground PM appears to be more inflammogenic than urban PM in epithelial cells, but there is a lack of research into effects on exposed individuals, especially those with underlying health conditions. This review summarises current knowledge about the effects of PM on the airway epithelium, how the effects of underground PM may be different to urban PM and the potential health consequences and mitigation strategies for commuters and workers in underground railways.

Testing physiologic monitor alarm customization software to reduce alarm rates and improve nurses' experience of alarms in a medical intensive care unit.

BACKGROUND: Clinicians in intensive care units experience alarm fatigue related to frequent false and non-actionable alarms produced by physiologic monitors. To reduce non-actionable alarms, alarm settings may need to be customized for individual patients; however, nurses may not customize alarms because of competing demands and alarm fatigue. OBJECTIVE: To examine the effectiveness and acceptance of physiologic monitor software to support customization of alarms. METHODS: This pre/post intervention study was conducted in a 56-bed medical intensive care unit. IntelliVue® Alarm Advisor customization support software for alarm limit violations was installed on all monitors and education on its use provided. For 2 months before and after implementation of the software, data were collected on patient characteristics from the electronic health record, alarm counts and duration from the monitoring system, and nurses' experience of alarms from a survey. RESULTS: Medium-priority heart rate, respiratory rate, and arterial pressure alarms were significantly reduced after software implementation (9.3%, 11.8%, and 15.9% reduction respectively; p<0.001 for all). The duration of these alarms was also significantly shorter (7.8%, 13.3%, and 9.3% reduction respectively; p<0.05 for all). The number and duration of SpO2 alarms did not decrease (p>0.05 for both). Patients post-intervention had worse Glasgow Coma Scale scores (p = 0.014), but otherwise were comparable to those pre-intervention. Nurses reported less time spent on non-actionable alarms post-intervention than pre-intervention (p = 0.026). Also lower post-intervention were the proportions of nurses who reported that alarms disturbed their workflow (p = 0.027) and who encountered a situation where an important alarm was ignored (p = 0.043). The majority (>50%) agreed that the software supported setting appropriate alarm limits and was easy to use. CONCLUSION: Alarm customization software was associated with a reduction in alarms. Use of software to support nurses' recognition of trends in patients' alarms and facilitate changes to alarm settings may add value to alarm reduction initiatives.

Correlation Between mMINDS and CIWA-Ar Scoring Tools in Patients With Alcohol Withdrawal Syndrome.

BACKGROUND: Many alcohol withdrawal scoring tools are used in hospitalized patients to assess the severity of alcohol withdrawal and guide treatment. The revised Clinical Institute Withdrawal Assessment (CIWA-Ar) and the modified Minnesota Detoxification Scale (mMINDS) are commonly used but have never been correlated. OBJECTIVE: To determine the strength of correlation between the CIWA-Ar and mMINDS scoring tools in patients with alcohol withdrawal syndrome. METHODS: A single-center, prospective correlation study conducted at a large academic medical center. Patients treated for alcohol withdrawal syndrome according to the Yale Alcohol Withdrawal Protocol were identified daily, and both the CIWA-Ar and mMINDS were administered at each time point required by the protocol. Clinical data were obtained from the electronic medical records. RESULTS: A total of 185 CIWA-Ar and mMINDS scores were collected in 30 patients. The Pearson correlation coefficient across all scores was 0.82, indicating a strong correlation. The Pearson correlation coefficient was 0.87 for CIWA-Ar scores of 10 or less and 0.52 for CIWA-Ar scores above 10. Strong correlations were also shown for tremor (0.98), agitation (0.84), and orientation (0.87). CONCLUSIONS: The correlation between the CIWA-Ar and mMINDS tools is strong and appears to be most robust in patients with CIWA-Ar scores of 10 or less.

Non-flushing of IV administration sets: an under-recognised under-dosing risk.

BACKGROUND: intravenous (IV) drugs are administered widely and under-dosing can result in therapy failure. The aim of this study was to quantify frequency, volume and dose of drug discarded within administration sets in the clinical setting. METHODS: residual volume for 24 different administration sets was measured under controlled conditions in a laboratory. Clinical assessment of current practice regarding post-infusion flushing occurred in 6 departments of one teaching hospital in the UK over 7 days. Details of drug last infused, (concentration, diluent and volume) and type and brand of administration set were collected. RESULTS: 74% of administration sets were not flushed. Non-flushing exceeded 90% and 61% for gravity and pump infusions respectively (p<0.001) in all areas excluding oncology. Oncology was the only area where flushing was standard practice for all infusions (p<0.001). Mean residual volume of the administration sets was 13.1 ml and 16.7 ml for gravity and pump sets respectively. Antibiotics were commonly infused and up to 21% of antibiotic dose was frequently discarded. CONCLUSIONS: the findings suggest disposal of substantial volumes of drugs occurs frequently in general hospital areas. Without clear national and local policies this unrecognised under-dosing will continue.

Extracellular granzyme K mediates endothelial activation through the cleavage of protease-activated receptor-1.

Granzymes are a family of serine proteases that were once thought to function exclusively as mediators of cytotoxic lymphocyte-induced target cell death. However, non-apoptotic roles for granzymes, including granzyme K (GzK), have been proposed. As recent studies have observed elevated levels of GzK in the plasma of patients diagnosed with clinical sepsis, we hypothesized that extracellular GzK induces a proinflammatory response in endothelial cells. In the present study, extracellular GzK proteolytically activated protease-activated receptor-1 leading to increased interleukin 6 and monocyte chemotactic protein 1 production in endothelial cells. Enhanced expression of intercellular adhesion molecule 1 along with an increased capacity for adherence of THP-1 cells was also observed. Characterization of downstream pathways implicated the mitogen-activated protein kinase p38 pathway for intercellular adhesion molecule 1 expression, and both the p38 and the extracellular signal-regulated protein kinases 1 and 2 pathways in cytokine production. GzK also increased tumour necrosis factor α-induced inflammatory adhesion molecule expression. Furthermore, the physiological inhibitor of GzK, inter-α-inhibitor protein, significantly inhibited GzK activity in vitro. In summary, extracellular GzK promotes a proinflammatory response in endothelial cells.

Testing for 'threads' and leucocyte esterase in first-void urine to exclude the diagnosis of non-specific urethritis in asymptomatic men.

Recent evidence suggests that asymptomatic nonspecific urethritis (NSU), which is not routinely tested for, is a clinically significant pathology.The aim of this pilot study was to determine if testing for urinary threads, leucocyte esterase (LE) or both in asymptomatic men is a good screening tool for NSU. Of the126 asymptomatic men, 8% met microscopic criteria for the diagnosis of NSU. The positive predictive value for NSU was 71% (95% confidence interval (CI): 29.3-95.5%) and the negative predictive value was 96% (95% CI: 92.8-99.5%). The absence of threads and negative LE makes urethritis highly unlikely, making urinary chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) testing sufficient. Incidental findings of further pathology occurred in 7%.

Differential expression of apoptosis related genes in selected strains of Aedes aegypti with different susceptibilities to dengue virus.

Aedes aegypti is the principal vector of Dengue viruses worldwide. We identified field collected insects with differential susceptibility to Dengue-2 virus (DENv-2) and used isofemale selection to establish susceptible and refractory strains based on midgut infection barriers. Previous experiments had identified higher expression of apoptosis-related genes in the refractory strain. To identify potential molecular mechanisms associated with DENv susceptibility, we evaluated the differential expression of Caspase-16, Aedronc, Aedredd, Inhibitor of apoptosis (AeIAP1) and one member of the RNAi pathway, Argonaute-2 in the midguts and fat body tissues of the selected strains at specific times post blood feeding or infection with DENv-2. In the refractory strain there was significantly increased expression of caspases in midgut and fatbody tissues in the presence of DENv-2, compared to exposure to blood alone, and significantly higher caspase expression in the refractory strain compared with the susceptible strain at timepoints when DENv was establishing in these tissues. We used RNAi to knockdown gene expression; knockdown of AeIAP1 was lethal to the insects. In the refractory strain, knockdown of the pro-apoptotic gene Aedronc increased the susceptibility of refractory insects to DENv-2 from 53% to 78% suggesting a contributing role of this gene in the innate immune response of the refractory strain.

Confirmation of association of FCGR3B but not FCGR3A copy number with susceptibility to autoantibody positive rheumatoid arthritis.

The FCGR locus encoding the low-affinity Fcγ receptors (FcγR) for immunoglobulin G has largely been missed by genome-wide association studies due to complications with structural variation and segmental duplication. Recently identified copy number variants (CNVs) affecting FCGR3A and FCGR3B have been linked to a number of autoimmune disorders. We have developed and validated a novel quantitative sequence variant assay in combination with an adapted paralogue ratio test to examine independent CNVs carrying FCGR3A and FCGR3B in rheumatoid arthritis (RA) compared with healthy volunteers (n = 1,115 and 654, respectively). Implementation of a robust statistical analysis framework (CNVtools) allowed for systematic batch effects and for the inherent uncertainty of copy number assignment, thus avoiding two major sources of false positive results. Evidence for association with neither duplications nor deletions of FCGR3A was found; however, in line with previous studies, there was evidence of overrepresentation of FCGR3B deletions in RA (odds ratio [OR] 1.50, P = 0.028), which was more apparent in rheumatoid factor positive disease (OR 1.61, P = 0.011). The level of FcγRIIIb, encoded by FCGR3B, expression on neutrophils was shown to correlate with gene copy number. Thus, our results may highlight an important role for neutrophils in the pathogenesis of RA, potentially through reduced FcγRIIIb-mediated immune complex clearance.

FcγRIIIa expression on monocytes in rheumatoid arthritis: role in immune-complex stimulated TNF production and non-response to methotrexate therapy.

OBJECTIVE: The expression of FcγRIIIa/CD16 may render monocytes targets for activation by IgG-containing immune complexes (IC). We investigated whether FcγRIIIa/CD16 was upregulated in rheumatoid arthritis (RA), associated with TNF production in response to IC-stimulation, and if this predicted response to methotrexate therapy. METHODS: FcγRIIIa/CD16 expression on CD14(low) and CD14++ monocytes was measured by flow cytometry in healthy controls and RA patients (early and long-standing disease). Intracellular TNF-staining was carried out after in vitro LPS or heat-aggregated immunoglobulin (HAG) activation. FcγRIIIa/CD16 expression pre- and post-steroid/methotrexate treatment was examined. RESULTS: Increased FcγRIIIa/CD16 expression on CD14++ monocytes in long-standing RA patients compared to controls was demonstrated (p = 0.002) with intermediate levels in early-RA patients. HAG-induced TNF-production in RA patients was correlated with the percentage of CD14++ monocytes expressing FcγRIIIa/CD16 (p<0.001). The percentage of CD14++ monocytes expressing FcγRIIIa/CD16 at baseline in early DMARD-naïve RA patients was negatively correlated with DAS28-ESR improvement 14-weeks post-methotrexate therapy (p = 0.003) and was significantly increased in EULAR non-responders compared to moderate (p = 0.01) or good responders (p = 0.003). FcγRIIIa/CD16 expression was not correlated with age, presence of systemic inflammation or autoantibody titers. CONCLUSION: Increased FcγRIIIa/CD16 expression on CD14++ monocytes in RA may result in a cell that has increased responsiveness to IC-stimulation. This monocyte subset may contribute to non-response to methotrexate therapy.

Proteinase inhibitor 9 is reduced in human atherosclerotic lesion development.

BACKGROUND: Granzyme B, a proapoptotic serine protease, is abundant in advanced, unstable atherosclerotic plaques, and it is suggested to contribute to plaque instability by inducing vascular smooth muscle cells apoptosis and by degrading plaque extracellular matrix. Proteinase inhibitor 9, the only known endogenous inhibitor of granzyme B in humans, confers protection against granzyme-B-induced apoptosis. However, the role of proteinase inhibitor 9 in atherosclerotic lesion development has yet to be determined. We hypothesized that atherosclerotic lesions have lower proteinase inhibitor 9 expression levels that will increase their susceptibility to granzyme-B-induced apoptosis. METHODS: Serial sections of human coronary arteries exhibiting different stages of lesion development were assessed by immunohistochemistry for proteinase inhibitor 9, α-smooth muscle cells actin, granzyme B, CD8, and active caspase-3. Frozen samples were analyzed by Western blot to evaluate total proteinase inhibitor 9 levels. RESULTS: Vascular smooth muscle cells express less proteinase inhibitor 9 as disease severity increases, and a significant difference in proteinase inhibitor 9 expression is observed between medial and intimal smooth muscle cells. High granzyme B levels colocalize with CD8+ cells and foam cells in the shoulder region and necrotic core area of advanced lesions. In advanced lesions, increased expression of activated caspase-3 in intimal SMC was associated with reduced proteinase inhibitor 9 expression in the presence of granzyme B. CONCLUSION: Reduced proteinase inhibitor 9 expression in human vascular smooth muscle cells is associated with atherosclerotic disease progression and is inversely related to the extent of apoptosis within the intima. Reduced proteinase inhibitor 9 expression may contribute to increased smooth muscle cell susceptibility to granzyme-B-induced apoptosis within the plaque.

Adapting to the new consensus guidelines for managing hyperglycemia during critical illness: the updated Yale insulin infusion protocol.

OBJECTIVE: To report our preliminary experience with the revised, more conservative Yale insulin infusion protocol (IIP) that targets blood glucose concentrations of 120 to 160 mg/dL. METHODS: We prospectively tracked clinical responses to the new IIP in our medical intensive care unit (ICU) by recording data on the first 115 consecutive insulin infusions that were initiated. All blood glucose values; insulin doses; nutritional support including intravenous dextrose infusions; caloric values for enteral and parenteral nutrition; and use of vasopressors, corticosteroids, and hemodialysis or continuous venovenous hemodialysis were collected from the hospital record. RESULTS: The IIP was used 115 times in 90 patients (mean age, 62 [±14 years]; 51% male; 35% ethnic minorities; 66.1% with history of diabetes). The mean admission Acute Physiology and Chronic Health Evaluation II score was 24.4 (±7.5). The median duration of insulin infusion was 59 hours. The mean baseline blood glucose concentration was 306.1 (±89.8) mg/dL, with the blood glucose target achieved after a median of 7 hours. Once the target was reached, the mean IIP blood glucose concentration was 155.9 (±22.9) mg/dL (median, 150 mg/dL). The median insulin infusion rate required to reach and maintain the target range was 3.5 units/h. Hypoglycemia was rare, with 0.3% of blood glucose values recorded being less than 70 mg/dL and only 0.02% being less than 40 mg/dL. In all cases, hypoglycemia was rapidly corrected using intravenous dextrose with no evident untoward outcomes. CONCLUSIONS: The updated Yale IIP provides effective and safe targeted blood glucose control in critically ill patients, in compliance with recent national guidelines. It can be easily implemented by hospitals now using the original Yale IIP.

Granzyme K activates protease-activated receptor-1.

Granzyme K (GrK) is a trypsin-like serine protease that is elevated in patients with sepsis and acute lung inflammation. While GrK was originally believed to function exclusively as a pro-apoptotic protease, recent studies now suggest that GrK may possess other non-cytotoxic functions. In the context of acute lung inflammation, we hypothesized that GrK induces pro-inflammatory cytokine release through the activation of protease-activated receptors. The direct effect of extracellular GrK on PAR activation, intracellular signaling and cytokine was assessed using cultured human lung fibroblasts. Extracellular GrK induced secretion of IL-6, IL-8 and MCP-1 in a dose- and time-dependent manner in lung fibroblasts. Heat-inactivated GrK did not induce cytokine release indicating that protease activity is required. Furthermore, GrK induced activation of both the ERK1/2 and p38 MAP kinase signaling pathways, and significantly increased fibroblast proliferation. Inhibition of ERK1/2 abrogated the GrK-mediated cytokine release. Through the use of PAR-1 and PAR-2 neutralizing antibodies, it was determined that PAR-1 is essential for GrK-induced IL-6, IL-8 and MCP-1 release. In summary, extracellular GrK is capable of activating PAR-1 and inducing fibroblast cytokine secretion and proliferation.

Perforin-independent extracellular granzyme B activity contributes to abdominal aortic aneurysm.

Granzyme B (GZMB) is a serine protease that is abundantly expressed in advanced human atherosclerotic lesions and may contribute to plaque instability. Perforin is a pore-forming protein that facilitates GZMB internalization and the induction of apoptosis. Recently a perforin-independent, extracellular role for GZMB has been proposed. In the current study, the role of GZMB in abdominal aortic aneurysm (AAA) was assessed. Apolipoprotein E (APOE)(-/-) x GZMB(-/-) and APOE(-/-) x perforin(-/-) double knockout (GDKO, PDKO) mice were generated to test whether GZMB exerted a causative role in aneurysm formation. To induce aneurysm, mice were given angiotensin II (1000 ng/kg/min) for 28 days. GZMB was found to be abundant in both murine and human AAA specimens. GZMB deficiency was associated with a decrease in AAA and increased survival compared with APOE-KO and PDKO mice. Although AAA rupture was observed frequently in APOE-KO (46.7%; n = 15) and PDKO (43.3%; n = 16) mice, rupture was rarely observed in GDKO (7.1%; n = 14) mice. APOE-KO mice exhibited reduced fibrillin-1 staining compared with GDKO mice, whereas in vitro protease assays demonstrated that fibrillin-1 is a substrate of GZMB. As perforin deficiency did not affect the outcome, our results suggest that GZMB contributes to AAA pathogenesis via a perforin-independent mechanism involving extracellular matrix degradation and subsequent loss of vessel wall integrity.