Neurotensin accelerates atherosclerosis and increases circulating levels of short-chain and saturated triglycerides

BACKGROUND AND AIMS

Obesity and type 2 diabetes are significant risk factors for atherosclerotic cardiovascular disease (CVD) worldwide, but the underlying pathophysiological links are poorly understood. Neurotensin (NT), a 13-amino-acid hormone peptide, facilitates intestinal fat absorption and contributes to obesity in mice fed a high-fat diet. Elevated levels of pro-NT (a stable NT precursor produced in equimolar amounts relative to NT) are associated with obesity, type 2 diabetes, and CVD in humans. Whether NT is a causative factor in CVD is unknown.

METHODS

Nt+/+ and Nt-/- mice were either injected with adeno-associated virus encoding PCSK9 mutants or crossed with Ldlr-/- mice and fed a Western diet. Atherosclerotic plaques were analyzed by en face analysis, Oil Red O and CD68 staining. In humans, we evaluated the association between baseline pro-NT and growth of carotid bulb thickness after 16.4 years. Lipidomic profiles were analyzed.

RESULTS

Atherosclerotic plaque formation is attenuated in Nt-deficient mice through mechanisms that are independent of reductions in circulating cholesterol and triglycerides but associated with remodeling of the plasma triglyceride pool. An increasing plasma concentration of pro-NT predicts atherosclerotic events in coronary and cerebral arteries independent of all major traditional risk factors, indicating a strong link between NT and atherosclerosis. This plasma lipid profile analysis confirms the association of pro-NT with remodeling of the plasma triglyceride pool in atherosclerotic events.

CONCLUSIONS

Our findings are the first to directly link NT to increased atherosclerosis and indicate the potential role for NT in preventive and therapeutic strategies for CVD.

Menopause at work-An organisation-based case study

AIM

The aim of the study was to explore and understand the organizational culture of a workplace in terms of support and well-being for staff experiencing perimenopausal and menopausal symptoms at work.

DESIGN

It is widely acknowledged that perimenopause and menopause symptoms are experienced by a large percentage of the female workforce. There is a lack of research into how nurses are supported through menopause (Cronin et al. Issues in Mental Health Nursing, 42, 2021, 541-548). The perimenopause and menopause transition can be a challenging time where many may require symptom management and support (RCN, The Menopause and Work: Guidance for RCN Representatives, 2020). This paper presents a case study research (CSR) approach to examine one healthcare organization.

METHODS

CSR design was used: A survey distributed to all staff employed, a review of the available documentation on menopause and interviews with managers from different levels of the organization. The COREQ consolidated criteria was used for reporting the qualitative research reported this study.

RESULTS

The case study generated both quantitative and qualitative data using surveys, interviews and documentation. Data from the organization (n = 6905) showed a majority female workforce of 81.9% with 40.6% aged between 41 and 55 years old, meaning a third of the organization working through perimenopause and menopause. Survey responses (n = 167) collected biographical and psychometric data on the prevalence of perimenopausal and menopausal symptoms. Seven managers were interviewed highlighting two themes: Access to support and culture of menopause and 13 documents from the organization on menopause were analysed for content. The study design permitted an iterative approach to data collection and providing an in-depth understanding of the needs and support for those experiencing perimenopause and menopause. The findings help healthcare organizations to understand their workforce and take in to account the larger numbers of female employees particularly nurses with the need to provide person-centred support mechanisms and an organizational approach for all employees.

Attitudes of women with gestational diabetes toward diet and exercise: a qualitative study

OBJECTIVE

Gestational diabetes (GDM) refers to glucose intolerance of varying severity first occurring in pregnancy. Following a diagnosis of GDM, exercise and dietary modification has a positive effect on improving glycemic control. Lifestyle changes affected in pregnancies affected by GDM have beneficial effects on long-term health if continued following birth. In addition, the psychological impact of a diagnosis of GDM should not be overlooked. Reports of maternal stress, anxiety, and fear are commonly reported issues in the literature. Support, both socially and from health care professionals, is also linked with higher rates of success in GDM management. Research to date had focused on women's reaction to a diagnosis of GDM, their mood and quality of life following a diagnosis, and their knowledge or opinions on the management of GDM. This qualitative study explored the attitudes of women with GDM toward these lifestyle changes, specifically diet and exercise. Women were also asked to identify advice that would be useful for other women newly diagnosed with GDM.

METHODS

With ethical approval a qualitative study was conducted using semi-structured interviews which were examined using Thematic Analysis. Patients were invited to participate and gave written consent after a discussion with a study researcher. The question plan for semi-structured interviews was designed with the advice of patient advocates. Recurrent themes were developed until the saturation of data.

RESULTS

Thirty-two women took part in the study. Time, convenience, and lack of educational awareness were common barriers to healthy eating and physical activity plans. Enablers for change included meal planning and organization. Women regarded their diets pre-diagnosis as healthy, with small "tweaks" (such as portion control) required to comply with recommendations. Another significant facilitator to change was support from the woman's partner. This also set a benchmark for plans of diet maintenance within the family structure after pregnancy. Unlike dietary changes, a consistent theme was that exercise was considered a "chore" in managing GDM and was unlikely to be continued in the long term. Practical advice offered by participants for other women with GDM included organization, realistic approaches, and lack of self-blame.

CONCLUSION

Women reported that changes in diet would be more achievable in the long term than changes in exercise patterns. Partners and the clinical team were significant sources of support. Women's views are crucial to providing clinicians with a comprehensive and holistic understanding of disease management. Involving women in self-care decisions and empowering women to manage their own health are key contributors to long-term behavior change as well as service provision and policy implementation.

Ticagrelor inhibits platelet aggregation and reduces inflammatory burden more than clopidogrel in patients with stages 4 or 5 chronic kidney disease

BACKGROUND

No study has compared pharmacologic properties of ticagrelor and clopidogrel in non-dialysis patients with stage 4-5 chronic kidney disease (CKD).

METHODS

We conducted a double-blind RCT to compare effects of ticagrelor and clopidogrel in 48 CKD, with the primary outcome of ADP-induced platelet aggregation (WBPA) after 2 weeks of DAPT. In a parallel arm, we compared effects of 2 weeks of ticagrelor plus aspirin on mean changes in WBPA and markers of thromboinflammation among non-CKD controls (n = 26) with that of CKD in the ticagrelor-arm.

RESULTS

Average age of CKD was 53.7 years, with 62% women, 54% African American, and 42% with stage 5 CKD. Ticagrelor generated statistically lower WBPA values post treatment [median 0 Ω (IQR 0, 2)] vs. clopidogrel [median 0 Ω (IQR 0, 5)] (P = 0.002); percent inhibition of WBPA was greater (87 ± 22% vs. 63 ± 50%; P = 0.04; and plasma IL-6 levels were much lower (8.42 ± 1.73 pg/ml vs. 18.48 ± 26.56 pg/ml; P = 0.04). No differences in mean changes in WBPA between CKD-ticagrelor and control groups were observed. Ticagrelor- DAPT reduced levels of IL-1α and IL-1β in CKD-ticagrelor and control groups, attenuated lowering of TNFα and TRAIL levels in CKD-ticagrelor (vs controls), and had global changes in correlation between various cytokines in a subgroup of CKD-ticagrelor subjects not on statins (n = 10). Peak/trough levels of ticagrelor/metabolite were not different between CKD-ticagrelor and control groups.

CONCLUSIONS

We report significant differences in platelet aggregation and anti-inflammatory properties between ticagrelor- and clopidogrel-based DAPT in non-dialysis people with stage 4-5 CKD. These notable inflammatory responses suggest ticagrelor-based DAPT might lower inflammatory burden of asymptomatic patients with stage 4 or 5 CKD. (clinicaltrials.gov # NCT03649711).

Platelet-Dependent Inflammatory Dysregulation in Patients with Stages 4 or 5 Chronic Kidney Disease: A Mechanistic Clinical Study

Background

Chronic kidney disease (CKD) is characterized by dysregulated inflammation that worsens with CKD severity. The role of platelets in modulating inflammation in stage 4 or 5 CKD remains unexplored. We investigated whether there are changes in platelet-derived thromboinflammatory markers in CKD with dual antiplatelet therapy (DAPT; aspirin 81 mg/d plus P2Y12 inhibitor).

Methods

In a mechanistic clinical trial, we compared platelet activation markers (aggregation and surface receptor expression), circulating platelet-leukocyte aggregates, leukocyte composition (monocyte subtypes and CD11b surface expression), and plasma cytokine profile (45 analytes) of non-CKD controls (n=26) and CKD outpatients (n=48) with a glomerular filtration rate (GFR) <30 ml/min per 1.73 m² on 2 weeks of DAPT.

Results

Patients with CKD demonstrated a reduced mean platelet count, elevated mean platelet volume, reduced platelet-leukocyte aggregates, reduced platelet-bound monocytes, higher total non-classic monocytes in the circulation, and higher levels of IL-1RA, VEGF, and fractalkine (all P<0.05). There were no differences in platelet activation markers between CKD and controls. Although DAPT reduced platelet aggregation in both groups, it had multifaceted effects on thromboinflammatory markers in CKD, including a reduction in PDGF levels in all CKD individuals, reductions in IL-1β and TNF-α levels in select CKD individuals, and no change in a number of other cytokines. Significant positive correlations existed for baseline IL-1β, PDGF, and TNF-α levels with older age, and for baseline TNF-α levels with presence of diabetes mellitus and worse albuminuria. Mean change in IL-1β and PDGF levels on DAPT positively correlated with younger age, mean change in TNF-α levels with higher GFR, and mean changes in PDGF, and TRAIL levels correlated with worse albuminuria. Minimum spanning trees plot of cytokines showed platelet-derived CD40L had a large reduction in weight factor after DAPT in CKD. Additionally, platelet-derived IL-1β and PDGF were tightly correlated with other cytokines, with IL-1β as the hub cytokine.

Conclusions

Attenuated interactions between platelets and leukocytes in the CKD state coincided with no change in platelet activation status, an altered differentiation state of monocytes, and heightened inflammatory markers. Platelet-derived cytokines were one of the central cytokines in patients with CKD that were tightly correlated with others. DAPT had multifaceted effects on thromboinflammation, suggesting that there is platelet-dependent and -independent inflammation in stage 4 or 5 CKD.

Trends and Outcomes of Oral Anticoagulation With Direct Current Cardioversion for Atrial Fibrillation/Flutter at an Academic Medical Center

Background

Increasing reports suggest the safe use of direct oral anticoagulants (DOACs) in electrical cardioversion. The aim of this study was to assess the trends and 30-day outcomes associated with anticoagulation for cardioversion.

Methods

Patients who underwent electrical cardioversion from January 2015 to October 2020 with a 30-day follow-up were included; and outcomes including stroke, transient ischemic attack, intracranial hemorrhage (ICH), and major gastrointestinal bleeding were recorded.

Results

Of the 515 patients, 351 (68%) were men and 164 (32%) were women, with a mean CHA2DS2VASc score of 2.6 ± 1.6. Outpatient apixaban use increased from 10% in 2015 to 46% in 2020 (P < 0.001) with a decline in the use of warfarin from 24% in 2015 to 10% in 2020 (P = 0.023). Apixaban use peri-procedurally for cardioversion increased from 32% in 2015 to 35% in 2020 (P = 0.317), while warfarin use decreased from 23% in 2015 to 14% in 2020 (P = 0.164). At discharge, apixaban prescriptions increased from 21% in 2015 to 61% in 2020 (P < 0.001), while warfarin prescriptions declined from 30% in 2015 to 13% in 2020 (P = 0.009). No ICH was recorded in the 30 days after cardioversion. Ischemic stroke occurred in four (0.7%) patients with one (0.29%) of the 338 patients on a DOAC, one (0.8%) of the 124 patients on warfarin and two (5.5%) of the 36 patients not receiving anticoagulation post cardioversion. There were seven (1%) major gastrointestinal bleeding events in patients on oral anticoagulation, of which four (3%) were on warfarin and three (0.8%) were on DOACs.

Conclusions

Our study shows the increasing and safe use of DOACs for the purpose of cardioversion. The rates of 30-day ischemic stroke post cardioversion were low and only occurred in patients admitted in the intensive care unit.

Bioactive lipids and metabolic syndrome-a symposium report

Recent research has shed light on the cellular and molecular functions of bioactive lipids that go far beyond what was known about their role as dietary lipids. Bioactive lipids regulate inflammation and its resolution as signaling molecules. Genetic studies have identified key factors that can increase the risk of cardiovascular diseases and metabolic syndrome through their effects on lipogenesis. Lipid scientists have explored how these signaling pathways affect lipid metabolism in the liver, adipose tissue, and macrophages by utilizing a variety of techniques in both humans and animal models, including novel lipidomics approaches and molecular dynamics models. Dissecting out these lipid pathways can help identify mechanisms that can be targeted to prevent or treat cardiometabolic conditions. Continued investigation of the multitude of functions mediated by bioactive lipids may reveal additional components of these pathways that can provide a greater understanding of metabolic homeostasis.

Clinical features and natural history of RASopathy-associated hypertrophic cardiomyopathy in children

Background

The RASopathies are a group of genetic disorders caused by germline mutations in genes encoding components of the RAS/MAPK signalling pathway and frequently associated with hypertrophic cardiomyopathy (HCM). The clinical features and outcomes of RASopathy-related HCM are incompletely understood and most published studies are limited by relatively small numbers and incomplete clinical characterisation.

Purpose

To describe the clinical features outcomes in a large, single-centre cohort of patients with RASopathy-associated HCM diagnosed &lt;18 years.

Methods

Data from 105 patients [68 (64.8%) males] diagnosed in childhood with RASopathy-associated HCM at a single specialist centre between 1985 and 2020 were retrospectively analysed.

Results

The RASopathy diagnosis was Noonan syndrome in 69 patients (65.7%); NSML in 10 (9.5%); CFC in 6 (5.7%); Costello in 5 (4.8%) and 15 patients (14.2%) had another Noonan-like variant. 72 patients (68.6%) had a pathogenic/likely pathogenic variant in a RAS-MAPK gene, most commonly PTPN11 [n=25 (34.7%)], followed by RAF 1 [n=13 (18.1%)]. 100 patients (95.2%) were probands, 9 (8.6%) had family history of cardiomyopathy and 2 (1.9%) family history of sudden cardiac death (SCD). 52 (49.5%) had concomitant congenital heart defects (CHD) [ASD 13 (25%), VSD 6 (11.5%), PDA 1 (1.9%), &gt;1 CHD 32 (61.5%)]. 29 (27.6%) had symptoms at baseline assessment and 56 (53.3%) were on cardiac medication. The distribution of left ventricular hypertrophy (LVH) was concentric in 47 (44.7%); 32 (30.5%) had asymmetric septal hypertrophy (ASH), and undocumented in 25 patients (23.8%). 45 patients (42.9%) had biventricular hypertrophy (BVH). Resting left ventricular outflow tract obstruction (LVOTO) was present in 39 (37.1%) with haemodynamically significant LVOTO (≥50mmHg) in 23 (21.9%). Resting right ventricular outflow tract obstruction (RVOTO) was present in 21 (20%). Over a median follow up time of 6 years, 19 patients (18.1%) died [1 (5.3%) SCD; 2 (10.5%) due to Heart Failure-related death; 1 (5.3%) due to another CVS cause; 5 (26.3%) due to a non-CVS cause and for 10 (52.6%) cause of death was unknown]. Incidence rate of death was calculated at 2.7 deaths per 100 person-years. Surgical septal myectomy was performed in 9 patients (8.6%) and 3 (2.9%) underwent cardiac transplantation. 14 patients (13.3%) suffered arrhythmic events [atrial tachycardia 6 (42.9%), Non-Sustained Ventricular Tachycardia 4 (3.8%), and Ventricular Tachycardia/Ventricular Fibrillation 4 (3.8%)].

Conclusion

To our knowledge, this is the largest cohort of RASopathy-associated HCM. The findings show a heterogeneous clinical presentation with a high prevalence of morbidity and mortality. Further work is needed to determine predictors of outcome in this population.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Onassis Foundation

COVID-19 and biomarkers of thrombosis: focus on von Willebrand factor and extracellular vesicles

COVID-19, caused by the SARS-CoV-2 virus, is responsible for a pandemic of unparalleled portion over the past century. While the acute phase of infection causes significant morbidity and mortality, post-acute sequelae that can affect essentially any organ system is rapidly taking on an equally large part of the overall impact on human health, quality of life, attempts to return to normalcy and the global economy. Herein, we summarize the potential role of von Willebrand Factor and extracellular vesicles toward understanding the pathophysiology, clinical presentation, duration of illness, diagnostic approach and management of COVID-19 and its sequelae.

Identifying Guideline-Practice Gaps to Optimize Evaluation and Management for Patients With Syncope

Syncope is a common and complex symptom that requires efficient evaluation to determine the cause. Recent guidelines focus on high-value testing, but a systematic evaluation of their implementation has not been performed. To this end, we used a mixed-methods approach of surveys, chart reviews, and focus groups to understand current practices relating to the diagnosis and management of patients with syncope and to identify barriers and facilitators to the implementation of guideline-supported recommendations. Surveys were distributed to 1500 providers in the specialties of hospital medicine, cardiology, emergency medicine, and family medicine, and 175 responses were received. Knowledge of class I and III guideline recommendations were assessed with the use of clinical vignettes, which were answered correctly 60%-80% of the time. Chart reviews focused on patient history and testing for syncope. Per the guidelines, < 50% of charts met criteria for bare minimum history and physical examination. Based on the documentation, 25% of echocardiograms and 90% of neurologic testing obtained would not have been appropriate per the guidelines. Self-reported and actual practice patterns were similar in rates of testing. Our results indicate that there remains a gap between guideline-directed management and actual practice for syncope. Focus groups revealed barriers across multiple levels of care that need to be addressed to improve care. Our findings emphasize the need for proactive strategies to improve syncope testing practices, potentially saving millions of dollars in the health care system.

Acute diabetic neuropathy following improved glycaemic control: a case series and review

SUMMARY

We present three cases of acute diabetic neuropathy and highlight a potentially underappreciated link between tightening of glycaemic control and acute neuropathies in patients with diabetes. Case 1: A 56-year-old male with poorly controlled type 2 diabetes (T2DM) was commenced on basal-bolus insulin. He presented 6 weeks later with a diffuse painful sensory neuropathy and postural hypotension. He was diagnosed with treatment-induced neuropathy (TIN, insulin neuritis) and obtained symptomatic relief from pregabalin. Case 2: A 67-year-old male with T2DM and chronic hyperglycaemia presented with left lower limb pain, weakness and weight loss shortly after achieving target glycaemia with oral anti-hyperglycaemics. Neurological examination and neuro-electrophysiological studies suggested diabetic lumbosacral radiculo-plexus neuropathy (DLPRN, diabetic amyotrophy). Pain and weakness resolved over time. Case 3: A 58-year-old male was admitted with blurred vision diplopia and complete ptosis of the right eye, with intact pupillary reflexes, shortly after intensification of glucose-lowering treatment with an SGLT2 inhibitor as adjunct to metformin. He was diagnosed with a pupil-sparing third nerve palsy secondary to diabetic mononeuritis which improved over time. While all three acute neuropathies have been previously well described, all are rare and require a high index of clinical suspicion as they are essentially a diagnosis of exclusion. Interestingly, all three of our cases are linked by the development of acute neuropathy following a significant improvement in glycaemic control. This phenomenon is well described in TIN, but not previously highlighted in other acute neuropathies.

LEARNING POINTS

A link between acute tightening of glycaemic control and acute neuropathies has not been well described in literature. Clinicians caring for patients with diabetes who develop otherwise unexplained neurologic symptoms following a tightening of glycaemic control should consider the possibility of an acute diabetic neuropathy. Early recognition of these neuropathies can obviate the need for detailed and expensive investigations and allow for early institution of appropriate pain-relieving medications.

Changes in thromboinflammatory profiles across the generations of transcatheter aortic heart valves

The transcatheter aortic valve replacement (TAVR) procedure was developed to provide patients with severe aortic stenosis an alternative to the surgical aortic valve replacement. Since the approval of the original SAPIEN the technology has rapidly evolved. While several approaches can be used for valve deployment, as delivery systems have become smaller and more flexible, the transfemoral approach has become the dominant technique for valve deployment. One hundred and forty five patients undergoing TAVR receiving one of four valve types (Sapien, Sapien XT, Sapien3 or CoreValve) via the femoral artery were included in this study. Platelet count, white blood cells count (WBC), Interleukin-6 (IL-6), and Serum Amyloid A (SAA) were determined before and after TAVR. Platelet counts declined after the procedure regardless of the valve type and were dependent upon the baseline platelet count. Use of conscious sedation blunted the decline in platelet count. With the newer generation valves, the rise in WBC post-TAVR was lower than observed with the Sapien, in keeping with less systemic inflammation. Consistent with WBC, IL-6 levels were lower following deployment of the newer generation valves. Elevations in plasma SAA, which occur following myocardial injury, were not reduced with the newer valves. Evolution of the TAVR technology has occurred rapidly over the last 5 years. The newer devices and smaller delivery systems are associated with less systemic inflammation, as reflected in WBC and plasma IL-6 levels. However, the acute phase reactant SAA remains unchanged, possibly reflecting different triggers for SAA following TAVR.

Early signatures of bleeding and mortality in patients on left ventricular assist device support: novel methods for personalized risk-stratification

Background: Left ventricular assist devices (LVADs) provide support for patients with end-stage heart failure. The aims of this study were to determine whether baseline analysis and early trends in routine laboratory data, platelet activity, and thromboinflammatory biomarkers following LVAD implantation reveal trends that predict personalized risks of one-year gastrointestinal (GI) bleeding, stroke, pump thrombosis, drive-line infections and mortality in patients on LVAD support. Methods: We performed an observational study at the University of Kentucky with 61 participants who underwent first-time LVAD implantation. Blood was collected at baseline and post-op days 0, 1, 3 and 6 as well as clinical follow-up. Demographics, clinical characteristics, one-year adverse events and routine laboratory data were collected from electronic medical records. Platelet function and plasma biomarkers were profiled. Results: Evaluation of routine laboratory results revealed that sustained thrombocytopenia and increased mean platelet volume (MPV) were associated with development of GI bleeding and mortality. Platelet function at follow-up visit predicted one-year bleeding events. Thrombotic biomarker sCD40L strongly predicted one-year GI bleeding at baseline before implantation and within the first week following LVAD implant. Conclusions: Early trends in routine bloodwork and platelet function may serve as novel signatures of patients at risk to experience adverse events.

Temporal trends, characteristics and outcomes of fibrinolytic therapy for ST-elevation myocardial infarction among patients 80 years or older

BACKGROUND

Pharmacologic reperfusion therapy is a recommended and effective strategy in patients with ST-elevation myocardial infarction (STEMI) when percutaneous coronary intervention (PCI) is not available. This study investigates temporal trends and outcomes of fibrinolytic therapy (FT) in elderly patients with STEMI.

METHODS

Using the Nationwide Inpatient Sample database, we extracted patients ≥80 years a primary diagnosis of STEMI admitted between 2010 and 2014. Using ICD codes, we identified patients who underwent FT. We performed temporal trend analysis, then compared characteristics and inpatient outcomes in the FT group versus no-FT group. Our primary outcome of interest was hemorrhagic stroke (HS). We also assessed the impact of HS on mortality and discharge to skilled nursing facility (SNF).

RESULTS

Of the 917,307 patients with STEMI, 16.1% (n = 147,874) were aged 80 or older. Primary PCI was performed in 46.2%, 2.4% underwent FT, and 51.3% had neither pharmacologic nor mechanical revascularization. The rate of FT increased (1.9%-2.4%) in a nonlinear trend over the five years of the study. The FT group was eight times more likely to suffer HS (P < 0.001). FT was an independent predictor of HS (OR 7.90, 95% CI 4.36-14.30; P < 0.001), whether they underwent PCI or not. HS was an independent predictor of mortality and SNF discharge.

CONCLUSION

FT in patients 80 years or older presenting with STEMI was associated with an eight-fold increase in HS and no associated mortality advantage, both with or without PCI. These data underscore the increased risk of FT in the elderly.

Ticagrelor Reduces Thromboinflammatory Markers in Patients With Pneumonia

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As expected, ticagrelor reduced ex-vivo ADP-induced aggregation in patients with pneumonia compared with placebo.

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Ticagrelor reduced platelet–leukocyte interactions as well as plasma interleukin-6 within 24 h in patients with pneumonia compared with placebo.

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Ticagrelor acutely altered NETosis biomarkers, whereas placebo had no effect.

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Ticagrelor improved lung function and reduced need for supplemental oxygen in patients with pneumonia compared with placebo.

Despite treatment advances for sepsis and pneumonia, significant improvements in outcome have not been realized. Antiplatelet therapy may improve outcome in pneumonia and sepsis. In this study, the authors show that ticagrelor reduced leukocytes with attached platelets as well as the inflammatory biomarker interleukin (IL)-6. Pneumonia patients receiving ticagrelor required less supplemental oxygen and lung function tests trended toward improvement. Disruption of the P2Y₁₂ receptor in a murine model protected against inflammatory response, lung permeability, and mortality. Results indicate a mechanistic link between platelets, leukocytes, and lung injury in settings of pneumonia and sepsis, and suggest possible therapeutic approaches to reduce complications.(Targeting Platelet-Leukocyte Aggregates in Pneumonia With Ticagrelor [XANTHIPPE]; NCT01883869)

Sex differences in the contemporary management of HIV patients admitted for acute myocardial infarction

BACKGROUND

Studies have reported sex differences in the management of patients with acute myocardial infarction (AMI) in the general population. This observational study is designed to evaluate whether sex differences exist in the contemporary management of human immunodeficiency virus (HIV) patients admitted for diagnosis of AMI.

HYPOTHESIS

There is no difference in management of HIV patients with AMI.

METHODS

Using the National Inpatient Sample database, we identified patients with a primary diagnosis of AMI and a secondary diagnosis of HIV. We described baseline characteristics and outcomes using NIS documentation. Our primary areas of interest were revascularization and mortality.

RESULTS

Among 2 977 387 patients presenting from 2010 to 2014 with a primary diagnosis of AMI, 10907 (0.4%) had HIV (mean age, 54.1 ± 9.3 years; n = 2043 [18.9%] female). Females were younger, more likely to be black, and more likely to have hypertension, diabetes, obesity, and anemia. Although neither males nor females were more likely to undergo coronary angiography in multivariate analysis, revascularization was performed less frequently in females than in males (45.4% vs 62.7%; P < 0.01), driven primarily by lower incidence of PCI. In a multivariate model, females were less likely to undergo revascularization (OR: 0.59, 95% CI: 0.45-0.78, P < 0.01), a finding driven solely by PCI (OR: 0.64, 95% CI: 0.49-0.83, P < 0.01). All-cause mortality was similar in both groups.

CONCLUSIONS

AMI was more common in males than females with HIV. Females with HIV were more likely to be younger and black and less likely to be revascularized by PCI.

Structure and Function of Murine αIIbβ3 (GPIIb/IIIa): Studies Using Monoclonal Antibodies and β3-null Mice

The αIIbβ3 receptor (GPIIb/IIIa) is the only platelet-specific integrin receptor and the most abundant adhesion/aggregation receptor on the surface of human platelets. Since mice are increasingly being used as models of human disease, we analyzed the structure and function of murine platelet αIIbβ3, utilizing both β3 integrin-deficient mice, who have a phenotype that resembles Glanzmann thrombasthenia, and our hamster monoclonal antibody (mAb) 1B5 to murine αIIbβ3. By immunoblot analysis, flow cytometry, and mAb binding studies, mouse platelets express abundant amounts of αIIbβ3 (60-80,000 copies/platelet). Like their human counterparts, murine αIIb and β3 exhibit different electrophoretic motilities under nonreducing (αIIb 135k Da; β3 92k Da) and reducing (αIIb 120k Da; β3 108k Da) conditions, and the αIIbβ3 complex is dissociated by EDTA at pH 8 and 37 ºC. Murine β3 is less susceptible to proteolysis by plasmin than is human β3. In addition to defective platelet aggregation, mouse platelets lacking αIIbβ3 and αVβ3 are unable to adhere to fibrinogen and prothrombin, but retain the ability to adhere to fibronectin and collagen. Following platelet activation, β3-null platelets express slightly less P-selectin than do wild-type mouse platelets. Moreover, β3-null platelets have altered tyrosine phosphorylation patterns following thrombinand collagen-induced aggregation. These results suggest fundamental similarities between human and mouse platelet activation and aggregation, but delineate subtle differences that need to be considered when comparing studies from mice and humans.

A Hamster Antibody to the Mouse Fibrinogen Chain Inhibits Platelet-fibrinogen Interactions and FXIIIa-mediated Fibrin Cross-linking, and Facilitates Thrombolysis

Murine models employing genetically altered mice have the potential to provide important new information about the hemostatic system, but before such data can be extrapolated to humans it is necessary to define the similarities and differences between murine and human hemostasis. After establishing the similarities of murine fibrinogen to human fibrinogen in its pattern of proteolysis in response to plasmin and its cross-linking by factor XIIIa, we studied a new hamster monoclonal antibody (mAb) 7E9 that reacts with the γ chain of mouse fibrinogen. This antibody inhibits platelet adhesion to fibrinogen, platelet-mediated clot retraction, platelet aggregation, and FXIIIa-mediated cross-linking of fibrin; it also facilitates tissue plasminogen activator (tPA)-mediated lysis of fibrin formed either in the absence or presence of platelets. These data provide evidence that the C-terminus of mouse fibrinogen γ chain, like that of human fibrinogen, is involved in fibrinogen binding to platelets and FXIIIa-mediated cross-linking of fibrin. Our data raise the possibility that a therapeutic agent that targets the C-terminus of the γ chain in human fibrinogen might have broad antithrombotic and profibrinolytic effects.

Acute Effects of Implantable Cardioverter-Defibrillator Shocks on Biomarkers of Myocardial Injury, Apoptosis, Heart Failure, and Systemic Inflammation

BACKGROUND

Implantable cardioverter-defibrillator (ICD) shocks are potentially associated with myocardial injury, altered hemodynamics, apoptosis, and inflammatory signaling. Their precise cellular impact can be explored after defibrillation testing (DFT) via biomarkers. We evaluated changes in biomarkers after ICD shocks during DFT.

METHODS

We prospectively enrolled outpatients presenting for first implantation of a cardiac device. Biomarkers indicative of myocardial injury, inflammation, and apoptosis were measured before and after implantation, and compared between patients receiving DFT (DFT+) to those not (DFT-).

RESULTS

Sixty-three patients were enrolled, 40 in the DFT+ group and 23 in the DFT- group. Average levels of troponin I, hsCRP, Calprotectin, N-terminal pro B-type natriuretic peptide (NTproBNP), and sFas increased by >50% after cardiac device implantation compared to baseline. Increase in troponin never exceeded the 50-fold upper limit of normal (2 ng/mL). Troponin trended higher in the DFT+ group at 8 hours (median 0.18 ng/mL, interquartile range [IQR] 0.11-0.48) versus the DFT- group (0.10 ng/mL, IQR 0.06-0.28, P = 0.0501); NTproBNP had a similar trend (P = 0.0581). sFas significantly increased in the DFT+ group from baseline (median 4663 pg/mL, IQR 2908-5679) to 24 hours (5039 pg/mL, IQR 3274-6261; P = 0.0338) but not in the DFT- group (P = 0.4705).

CONCLUSION

DFT testing is associated with acutely increased plasma levels of troponin and sFas, a biomarker of apoptosis, along with a trend toward higher NTproBNP.

Abstract 467: Lipid Phosphate Phosphatase 3 in Smooth Muscle Cells Suppresses the Development of Atherosclerosis

Lipid phosphate phosphatase3 (LPP3) encoded by the PPAP2B gene, is an integral membrane enzyme that degrades bioactive lysophospholipids including lysophosphatidic acid (LPA), sphingosine-1-phosphate (S1P) and related bioactive lipids. These bioactive lipids regulate a wide variety of cellular functions such as proliferation, apoptosis and differentiation. We suggest that LPP3 hydrolysis of LPA is a critical step in regulating pathophysiological important responses in vascular cells. To test this hypothesis, we generated mice lacking LPP3 by breeding Ppap2B fl / fl mice (fl/fl) animals expressing Cre recombinase under control of the SM22 promoter on the LDLr-/- background. At weaning, littermate SM22-Δ and fl/fl mice were fed Western Diet (WD) for 12 weeks. LPP3 expression in aortic SMCs was reduced (0.139 ± 0.0246 vs 1.0 ± 0; P < 0.001) and LPA content was significantly higher (9.32 ± 4.66 vs 5.66 ± 2.65; P < 0.05) in the aortic arch in SM22-Δ mice compared to control fl/fl mice. SM22-Δ mice demonstrated increased atherosclerotic lesions (18.98 ± 7.11% vs 6.06 ± 4.01%; P < 0.001), measured by en face analysis, of the aorta and significantly higher IL-6 expression (18.83 ± 2.87 vs 3.59 ± 8.92; P < 0.05) in the aortic arch. Sections of aorta at the level of the aortic root indicated that the loss of LPP3 upregulate CD68 and α-SMA staining. These results reveal that LPP3 normally functions to suppress atherosclerosis. LPP3 deficiency increases vascular LPA content, may promote the infiltration of inflammatory cells as macrophages into lesions and smooth muscle cell proliferation to accelerate the development of atherosclerosis.

Abstract 396: Diet-derived Lysophosphatidic Acid and Obesity-associated Cardiovascular Disease Risk

Diet-dependent obesity is a risk factor for coronary artery disease and a powerful risk factor for some cancers particularly in women. One mechanism that has been proposed to link diet-dependent obesity to disease is that diets high in fats and lipids promote the formation of bioactive lipid metabolites that increase disease risk. Lysophosphatidic acid (LPA) is a family of bioactive lysophospholipids that elicit broadly mitogenic and proinflammatory responses in multiple cell types, primarily through actions at cell surface G-protein coupled receptors. LPA promotes vascular smooth muscle cell differentiation and migration, decreases vascular barrier endothelial function, activates platelets and myeloid cells all of which could contribute to the development of atherosclerosis. In mice, genetic and pharmacological targeting of LPA receptors inhibits atherosclerosis. We conducted studies to investigate the impact of fasting and high fat feeding on circulating levels, metabolic sources and distribution of plasma LPA in both humans and mice. After overnight fasting, blood was drawn from human volunteers to obtain baseline LPA levels before being given a drink supplemented with fats to provide approximately 50% of daily energy requirement. Blood was subsequently drawn at intervals to prepare plasma. In mice, after overnight fasting, the animals were gavaged with olive oil either with or without a tracer phosphatidylcholine. These studies were extended to mice with genetically induced hyperlipidemia fed models of diet. Changes in plasma LPA levels were measured by using HPLC ESI multistage mass spectrometry. We found that plasma LPA levels in mice and humans are acutely sensitive to fasting and high fat feeding. In mice plasma LPA levels are dramatically increased by a combination of feeding a high fat atherogenic diet and genetic induction of hyperlipidemia by inactivation of the LDLr or apoE genes. In addition, in mice, plasma LPA can be formed from dietary phosphatidylcholine. These results provide support for the concept that high fat atherogenic diets promote the formation of circulating LPA and have led to development and characterization of mouse models that can be used to define the role of LPA in obesity in other disease processes including cancer.

Abstract 576: The Role of Adipose Derived Autotaxin on Inflammation Associated with Cardiovascular Disease

Obesity is an established risk factor for cardiovascular disease (CVD) and stroke, and the cardiovascular complications of obesity are a leading cause of potentially preventable death. Recent evidence suggests that increased cardiovascular mortality in patients with obesity may not be fully explained by associated risk factors such as dyslipidemia, hyperglycemia, insulin resistance and hypertension. In addition to contributing to traditional CVD risk factors, obesity is also characterized by a chronic sub-acute inflammatory state termed “metainflammation” involving increased circulating inflammatory cytokines. Autotaxin (ATX), encoded by the ecto-nucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) gene, is a potent cell motility-stimulating factor that is secreted by adipose tissue. ATX hydrolyzes lysophosphatidylcholine (LPC), a lipid that is abundant in the circulation, to lysophosphatidic acid (LPA). The main objective of this study was to explore whether adipose ATX contributes to systemic inflammatory responses in obesity. We established two animal models with reduced ATX expression: MX-1 Cre-mediated deletion of the ENPP2 gene to generate a global ATX loss (Mx1) and Adipoq-Cre mediated loss of ATX expression in adipocytes (AdipoQ). Mice were fed a high fat diet for up to 20 weeks. No differences in body weight between the ENPP2 loss and littler mate controls were found. RNA and proteins were extracted, qPCR and western blots were performed for ATX and inflammatory cytokines; MCP, TNF and IFN. Results demonstrate that mice lacking global or adipose-derived ATX display approx 2 fold lower adipose inflammation. Furthermore, LPS was used to provoke a systemic response in mice that had been on a HFD for 10 weeks. Six hours after LPS injection, RNA was extracted and qPCR performed for IL6, IL1beta and IFN gamma. In response to a LPS challenge, AdipoQ mice showed a 2 fold reduction in inflammatory response in adipose tissue. The data generated from these experiments will provide important insight into potential mechanisms of how ATX and adipose tissue influence obesity induced inflammation and results from this and future projects may identify potential therapeutic targets to prevent and treat obesity induced inflammation and CVD.

Abstract 45: Characterization of a Novel Integrin Binding Protein that is Essential for αIIbβ3 Outside-in Signaling and Hemostasis

Integrins are heterodimeric (α/β) membrane proteins that play fundamental roles in many biological processes, e.g. cell adhesion and spreading, which are important for platelet function and hemostasis. Integrin function is modulated by bi-directional transmembrane signaling: inside-out and outside-in, which is mediated through the interactions between integrin cytoplasmic tails and intracellular, regulatory proteins. Here, we show that VPS33B, a member of the Sec1/Munc18 (SM) family and component of the Class C core of the CORVET/HOPS sorting complexes, binds directly to the β subunit. Overexpression of VPS33B in CHO cells potentiated α IIb β 3 outside-in signaling but not inside-out signaling. Platelets, from megakaryocyte- and platelet-specific VPS33B conditional knockout mice we generated, had normal morphology yet their spreading on fibrinogen was impaired and they failed to support clot retraction. Platelet aggregation and ATP secretion in response to low-dose thrombin were reduced in the VPS33B knockout mice. α IIb β 3 -mediated endocytosis of fibrinogen was also defective. Tail bleeding times were prolonged in the VPS33B knockout mice. Furthermore, VPS33B acted upstream of the RhoA-ROCK-MLC and Rac1 dependent pathways that leads to clot retraction and cell spreading, respectively. Our work demonstrates that vesicular trafficking complexes are a novel class of modifiers of integrin function and in hemostasis. Our data also provide insights into the molecular mechanism and treatment of ARC syndrome.

Abstract 158: PPAP2B Expression Regulates the Development of Atherosclerosis

Coronary artery disease (CAD) is the leading cause of death in both men and women worldwide. The bioactive lipid lysophosphatidic acid (LPA) accumulates in human atheroma compared to levels in healthy control tissue. LPA can be degraded by the membrane protein lipid phosphate phosphatase 3 (LPP3), encoded by the gene PPAP2B. Noncoding polymorphisms in PPAP2B associate with CAD risk, and gene expression analysis indicates that individuals possessing the risk allele exhibit lower levels of PPAP2B mRNA in leukocytes and vascular cells. We hypothesize that decreased LPP3, as a result of low PPAP2B expression, accelerates experimental atherosclerosis. Murine models of tissue specific LPP3 knockdown were generated using the Cre-Lox system driven by either the MX-1 promoter (MX-1Δ) or the smooth muscle cell specific SM22 promoter (SM22Δ) in mice on the atherogenic LDLr -/- background. Following 12 weeks on Western diet, knockdown of LPP3 in both the MX-1Δ and the SM22Δ mice resulted in significantly more atherosclerosis by en face analysis compared to LPP3-fl/fl littermate controls. LPA content determined using LC/MS/MS tended to be higher in the proximal aortas of MX-1Δ and SM22Δ knockdown mice compared to controls. Significantly higher macrophage gene expression was observed in the MX-1Δ mice while IL-6 levels were significantly higher in the SM22Δ mice compared to controls. Finally, targeting LPP3 expression in the MX-1Δ, but not the SM22Δ, mice resulted in significantly higher circulating levels of LPA compared to controls. These results are consistent with accelerated atherosclerosis in LPP3 knockdown mice and suggest a protective role for LPP3 in CAD. Increased vascular LPA content, as a consequence of decreased LPP3 expression, may promote the infiltration of monocyte/macrophages into lesions as well as exacerbate inflammation to accelerate the development of CAD. Our findings provide mechanistic insight into the genome wide association studies that linked genetic variation in PPAP2B with risk of CAD and focus attention on the LPA/ LPP3 signaling nexus as a novel therapeutic strategy to prevent atherosclerosis.

Abstract 656: Lipid Phosphate Phosphatase-3 Mediated Inflammation and Angiogenesis

A recent meta-analysis of genome-wide association studies (GWAS) of coronary artery disease (CAD) involving over 86,000 individuals identified PPAP2B (gene that encodes lipid phosphate phosphatase-3; LPP3) as 1 of 13 new loci that associate with CAD. The PPAP2B loci independently predicted CAD (P = 3.81 X 10-19) and lacked association with traditional risk factors. The lipid phosphate phosphatase 3 is a cell surface integral membrane protein that regulates the bio availability of major bioactive lysophospholipids, like lysophosphatidic acid (LPA). Our group also made the surprising discovery that tissue-specific deficiency of LPP3 exaggerates vascular inflammation and promotes the development of neointima after vascular injury. Here we present evidence that enothelial cell LPP3 serves as an intrinsic negative regulator of vascular inflammation, promotes endothelial barrier function. Our results suggest that loss of LPP3 by siRNA mediated knockdown enhanced proliferation with elevated pErk signaling whereas migration was inhibited in human microvascular endothelial cells (HMEC). The endothelial cells that were silenced for LPP3 were further subjected LPA receptor knockdown and we found that although LPA-induced Erk phosphorylation was similar between LPA 1 and LPA 4 silencing, LPA 4 silencing resulted in enhancement of Akt phosphorylation at Thr-308 in response to LPA. Dual inhibition of LPA 1 and LPA 4 abolished LPA mediated migration in LPP3 silenced HMEC suggesting that the signaling response is mediated through the LPA 1 receptor. Rac activation in response to LPA was barely detectable in LPP3 silenced HMEC, which correlated with its weak migratory response. In contrast, a prominent increase in Rac-GTP levels was observed upon LPA 4 silencing under these conditions. Activation of HMEC with LPA increased phosphorylation of MSK downstream of p38, and CREB phosphorylation was inhibited upon LPA 4 receptor blockade in LPP3 silenced endothelial cells.

Metabolic abnormalities among people diagnosed with schizophrenia: a literature review and implications for mental health nurses

Metabolic abnormalities such as diabetes, obesity and dyslipidaemia are found in much higher rates in people with a diagnosis of schizophrenia when compared with the general population. This review discusses the most prevalent metabolic abnormalities associated with schizophrenia, their frequency and implications for mental health nurses (MHN). This review illuminates the need for MHN to acquire added awareness, knowledge and practical strategies in managing people at high risk of developing metabolic abnormalities associated with MetS. By doing this, it contributes to the literature by highlighting practical strategies for MHN in assessment and ongoing monitoring of metabolic abnormalities in clinical practice. This review highlights the need for MHN to be vigilant in monitoring a person's physical state on commencement and throughout treatment with antipsychotics. There is a need for an early detection monitoring system for people who are potentially at risk of developing metabolic abnormalities. The literature review aimed to investigate metabolic abnormalities associated with metabolic syndrome (MetS) in people diagnosed with schizophrenia; they are almost twice as likely to have metabolic risk factors and die approximately 20 years younger than the general population. MetS has become an issue of growing concern in mental health nursing. A comprehensive literature review was conducted utilizing various databases to address the reviews aim. Databases such as CINAHL Plus with full text (via EBSCO), MEDLINE(R) (OVID), PsycINFO and the COCHRANE library were accessed. The main metabolic abnormalities that emerged were: diabetes, obesity and dyslipidaemia. Antipsychotic medication also plays a vital role in a person's susceptibility to the development of MetS. It is critical that MHN has access to training and education in managing people at high risk of developing metabolic abnormalities associated with MetS. This review contributes to the literature by highlighting practical strategies for MHN in assessment and ongoing monitoring of metabolic abnormalities in clinical practice.

The effect of level of crude protein and available lysine on finishing pig performance, nitrogen balance and nutrient digestibility

Two trials were conducted to investigate the effect of decreasing the crude protein (CP) content of diets for finishing pigs containing two levels of available lysine on nutrient digestibility, nitrogen (N) balance and production performance. Ten finishing diets containing five levels of CP (on average 144, 155, 168, 182 and 193 g/kg fresh basis) and two levels of available lysine (6.9 and 8.2 g/kg fresh basis) were formulated. The diets were offered to pigs on a performance trial (n = 800 Large White (LW)×Landrace (LR) pigs) from 10 wk of age until finish at 21 wks+5 d of age. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. In addition, a digestibility/N balance trial was conducted using pigs (n = 80 LW×LR) housed in metabolism crates. Digestibility of dry matter (DM), CP, oil, fibre and energy was determined. N balance values were determined through analysis of N content of urine and faeces (‘as determined’). N balance values were also calculated using ADG values and assuming that 16% of growth is protein deposition (“as calculated”). Pig performance was poor between 10 and 13 wk of age which indicated that the dietary treatments were nutritionally inadequate for pigs less than 40 kg. There was a significant (p<0.01) quadratic effect of increasing CP level on feed intake, ADG and FCR from 10 to 13 wk which indicated that the lower CP levels did not supply adequate levels of essential or non-essential amino acids. There was no effect of increasing available lysine level throughout the early period, which in conjunction with the response in older pigs, suggested that both 8.2 and 6.9 g/kg available lysine were insufficient to drive optimum growth. There was a positive response (p<0.05) to increasing available lysine level from 13 wk to finish which indicated that 6.9 g/kg available lysine was not adequate for finishing pigs. Energy digestibility decreased with decreasing CP level of diets containing 6.9 g/kg available lysine which may be attributed to the higher fibre content of the lower CP diets. Nitrogen excretion (g/d) was lowered when dietary CP was reduced regardless of whether the values were determined through balance or calculated using ADG. Calculated N excretion decreased linearly (p<0.001) and quadratically (p<0.001) with decreasing dietary CP content. When the N balance figures calculated in this study were compared with those quoted in the Northern Ireland and English Nitrates Directive Action Programmes, N excretion was less per pig (wean to finish) offered a 169 g/kg CP, 8.2 g/kg available lysine diet (2.39 kg vs 3.41 kg (Northern Ireland) and 2.93 kg (England)).

QRS duration predicts death and hospitalization among patients with atrial fibrillation irrespective of heart failure: evidence from the AFFIRM study

AIMS

The association of QRS duration (QRSd) with morbidity and mortality is understudied in patients with atrial fibrillation (AF). We sought to assess any association of prolonged QRS with increased risk of death or hospitalization among patients with AF.

METHODS AND RESULTS

QRS duration was retrieved from the baseline electrocardiograms of patients enroled in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study and divided into three categories: <90, 90-119, ≥120 ms. Cox models were applied relating the hazards of mortality and hospitalizations to QRSd. Among 3804 patients with AF, 593 died and 2305 were hospitalized. Compared with those with QRS < 90 ms, patients with QRS ≥ 120 ms, had an increased mortality [hazard ratio (HR) 1.61, 95% confidence interval (CI): 1.29-2.03, P < 0.001] and hospitalizations (HR 1.14, 95% CI: 1.07-1.34, P = 0.043) over an average follow-up of 3.5 years. Importantly, for patients with QRS 90-119 ms, mortality and hospitalization were also increased (HR 1.31, P = 0.005 and 1.11, P = 0.026, respectively). In subgroup analysis based on heart failure (HF) status (previously documented or ejection fraction <40%), mortality was increased for QRS ≥ 120 ms patients with (HR 1.87, P < 0.001) and without HF (HR 1.63, P = 0.02). In the QRS 90-119 ms group, mortality was increased (HR 1.38, P = 0.03) for those with HF, but not significantly among those without HF (HR 1.23, P = 0.14).

CONCLUSION

Among patients with AF, QRSd ≥ 120 ms was associated with a substantially increased risk for mortality (all-cause, cardiovascular, and arrhythmic) and hospitalization. Interestingly, an increased mortality was also observed among those with QRS 90-119 ms and concomitant HF.

Increased mortality among patients taking digoxin--analysis from the AFFIRM study

AIMS

Digoxin is frequently used for rate control of atrial fibrillation (AF). It has, however, been associated with increased mortality. It remains unclear whether digoxin itself is responsible for the increased mortality (toxic drug effect) or whether it is prescribed to sicker patients with inherently higher mortality due to comorbidities. The goal of our study was to determine the relationship between digoxin and mortality in patients with AF.

METHODS AND RESULTS

The association between digoxin and mortality was assessed in patients enrolled in the AF Follow-Up Investigation of Rhythm Management (AFFIRM) trial using multivariate Cox proportional hazards models. Analyses were conducted in all patients and in subsets according to the presence or absence of heart failure (HF), as defined by a history of HF and/or an ejection fraction <40%. Digoxin was associated with an increase in all-cause mortality [estimated hazard ratio (EHR) 1.41, 95% confidence interval (CI) 1.19-1.67, P < 0.001], cardiovascular mortality (EHR 1.35, 95% CI 1.06-1.71, P = 0.016), and arrhythmic mortality (EHR 1.61, 95% CI 1.12-2.30, P = 0.009). The all-cause mortality was increased with digoxin in patients without or with HF (EHR 1.37, 95% CI 1.05-1.79, P = 0.019 and EHR 1.41, 95% CI 1.09-1.84, P = 0.010, respectively). There was no significant digoxin-gender interaction for all-cause (P = 0.70) or cardiovascular (P = 0.95) mortality.

CONCLUSION

Digoxin was associated with a significant increase in all-cause mortality in patients with AF after correcting for clinical characteristics and comorbidities, regardless of gender or of the presence or absence of HF. These findings call into question the widespread use of digoxin in patients with AF.

Abstract 228: Secretion of Bone Marrow--Derived Cells Contributes to Pressure-Overload--Induced Left Ventricular Hypertrophy

Bone marrow derived cells, especially inflammatory cells, may contribute to the pathological progression of pressure overload induced left ventricular (LV) hypertrophy and cardiac fibrosis. Previously, we reported that inflammatory cell accumulation and upregulation of cytokines in hearts of mice that had undergone transverse aortic constriction (TAC) surgery predicted later cardiac hypertrophic and fibrotic remodeling. However, the underlining mechanisms are still not clear. One potential mechanism for inflammatory cells to modulate their environment and affect surrounding cells is through release of cargo stored in granules. Jinx mice - which contain a single point mutation in Unc13d encoding the Munc13-4 protein, a limiting factor in vesicular priming and fusion - have defects in granular secretion in hematopoietic cells, such as platelets, NK cells, and neutrophils. In the current study, we investigated the role of bone marrow cell granule secretion in TAC-induced LV remodeling by creating with bone marrow transplantation chimeric mice specifically lacking Munc13-4 in marrow derived cells. Both wild-type mice (WT) that were transplanted with WT bone marrow and WT mice that received Jinx bone marrow developed LVH and a classic fetal reprogramming response early (7 days) after TAC. However, at later times (5 weeks), mice lacking Munc13-4 in bone marrow-derived cells failed to sustain the cardiac hypertrophy observed in mice with WT bone marrow. No difference in cardiac fibrosis was observed at early or late times. These results suggest that sustained LVH in the setting of pressure overload depends on factor(s) secreted from bone marrow-derived cells, likely from either platelets, NK cells and/or neutrophils. Inhibiting granule cargo release may represent a novel therapeutic target to prevent the development of LVH.