Endothelial Poldip2 regulates sepsis-induced lung injury via Rho pathway activation.

AIMS: Sepsis-induced lung injury is associated with significant morbidity and mortality. Previously, we showed that heterozygous deletion of polymerase δ-interacting protein 2 (Poldip2) was protective against sepsis-induced lung injury. Since endothelial barrier disruption is thought to be the main mechanism of sepsis-induced lung injury, we sought to determine if the observed protection was specifically due to the effect of reduced endothelial Poldip2. METHODS AND RESULTS: Endothelial-specific Poldip2 knock-out mice (EC-/-) and their wild-type littermates (EC+/+) were injected with saline or lipopolysaccharide (18 mg/kg) to model sepsis-induced lung injury. At 18 h post-injection mice, were euthanized and bronchoalveolar lavage (BAL) fluid and lung tissue were collected to assess leucocyte infiltration. Poldip2 EC-/- mice showed reduced lung leucocyte infiltration in BAL (0.21 ± 0.9×106 vs. 1.29 ± 1.8×106 cells/mL) and lung tissue (12.7 ± 1.8 vs. 23 ± 3.7% neutrophils of total number of cells) compared to Poldip2 EC+/+ mice. qPCR analysis of the lung tissue revealed a significantly dampened induction of inflammatory gene expression (TNFα 2.23 ± 0.39 vs. 4.15 ± 0.5-fold, IκBα 4.32 ± 1.53 vs. 8.97 ± 1.59-fold), neutrophil chemoattractant gene expression (CXCL1 68.8 ± 29.6 vs. 147 ± 25.7-fold, CXCL2 65 ± 25.6 vs. 215 ± 27.3-fold) and a marker of endothelial activation (VCAM1 1.25 ± 0.25 vs. 3.8 ± 0.38-fold) in Poldip2 EC-/- compared to Poldip2 EC+/+ lungs. An in vitro model using human pulmonary microvascular endothelial cells was used to assess the effect of Poldip2 knock-down on endothelial activation and permeability. TNFα-induced endothelial permeability and VE-cadherin disruption were significantly reduced with siRNA-mediated knock-down of Poldip2 (5 ± 0.5 vs. 17.5 ± 3-fold for permeability, 1.5 ± 0.4 vs. 10.9 ± 1.3-fold for proportion of disrupted VE-cadherin). Poldip2 knock-down altered expression of Rho-GTPase-related genes, which correlated with reduced RhoA activation by TNFα (0.94 ± 0.05 vs. 1.29 ± 0.01 of relative RhoA activity) accompanied by redistribution of active-RhoA staining to the centre of the cell. CONCLUSION: Poldip2 is a potent regulator of endothelial dysfunction during sepsis-induced lung injury, and its endothelium-specific inhibition may provide clinical benefit.

The effects of sepsis on endothelium and clinical implications.

ABSTRACT: Sepsis accounts for nearly 700 000 deaths in Europe annually and is caused by an overwhelming host response to infection resulting in organ failure. The endothelium is an active contributor to sepsis and as such represents a major target for therapy. During sepsis, endothelial cells amplify the immune response and activate the coagulation system. They are both a target and source of inflammation and serve as a link between local and systemic immune responses. In response to cytokines produced by immune cells, the endothelium expresses adhesion molecules and produces vasoactive compounds, inflammatory cytokines, and chemoattractants, thus switching from an anticoagulant to procoagulant state. These responses contribute to local control of infection, but systemic activation can lead to microvascular thrombosis, capillary permeability, hypotension, tissue hypoxia, and ultimately tissue damage. This review focuses on the role of the endothelium in leucocyte adhesion and transmigration as well as production of reactive oxygen and nitrogen species, microRNAs and cytokines, formation of signalling microparticles, and disseminated intravascular coagulation. We also discuss alterations in endothelial permeability and apoptosis. Finally, we review the diagnostic potential of endothelial markers and endothelial pathways as therapeutic targets for this devastating disease.

An acceleration in hypertension-related mortality for middle-aged and older Americans, 1999-2016: An observational study.

BACKGROUND: Hypertension-related mortality has been increasing in recent years; however, limited information exists concerning rate, temporal, secular, and geographic trends in the United States. METHODS AND RESULTS: Using CDC death certificate data spanning 1999-2016, we sought to delineate trends in deaths attributable to an underlying cause of hypertension using joinpoint regression and proportion testing. From 1999-2016, the hypertension-related mortality rate increased by 36.4% with an average annual percent change (AAPC) of 1.8% for individuals ≥ 35 years of age. Interestingly, there was a notable acceleration in the AAPC of hypertension mortality between 2011 and 2016 (2.7% per year). This increase was due to a significant uptick in mortality for individuals ≥ 55 years of age with the greatest AAPC occurring in individuals 55-64 (4.5%) and 65-74 (5.1%) years of age. Increased mortality and AAPC were pervasive throughout sex, ethnicity, and White and American Indian or Alaska Native race, but not Black or African American race. From 2011-2016, there were significant increases in AAPC for hypertension-related mortality with contributing causes of atrial fibrillation, heart failure, diabetes, obesity, and vascular dementia. Elevated mortality was observed for conditions with a contributing cause of hypertension that included chronic obstructive pulmonary disease, diabetes, Alzheimer's, Parkinson's, and all types of falls. Geographically, increases in AAPCs and mortality rates were observed for 25/51 States between 2011 and 2016. CONCLUSIONS: Our results indicate hypertension-related mortality may have accelerated since 2011 for middle-aged and older Americans, which may create new challenges in care and healthcare planning.

Platelet microRNAs and vascular injury.

Vascular smooth muscle cell (VSMC) phenotype switching from a contractile state to a synthetic phenotype has been implicated in intimal remodeling during vascular injury. While multiple studies have focused on dedifferentiation of VSMCs, prevention of VSMC-mediated excessive repair remains poorly understood. In this issue of the JCI, Zeng et al. identified a mechanism by which platelet-derived microRNA-223 (miRNA-223) reverses VSMC dedifferentiation. The authors show that suppression of proliferation occurs after platelet internalization by VSMCs. Moreover, they demonstrate that miRNA-223 inhibits dedifferentiation and intimal hyperplasia in diabetic mice by decreasing PDGFRß expression in VSMCs. Together, these results identify platelet-derived miRNA-223 as a potential therapeutic target in vascular injury.

Common Coding Variants in SCN10A Are Associated With the Nav1.8 Late Current and Cardiac Conduction.

BACKGROUND: Genetic variants at the SCN5A/SCN10A locus are strongly associated with electrocardiographic PR and QRS intervals. While SCN5A is the canonical cardiac sodium channel gene, the role of SCN10A in cardiac conduction is less well characterized. METHODS: We sequenced the SCN10A locus in 3699 European-ancestry individuals to identify variants associated with cardiac conduction, and replicated our findings in 21,000 individuals of European ancestry. We examined association with expression in human atrial tissue. We explored the biophysical effect of variation on channel function using cellular electrophysiology. RESULTS: We identified 2 intronic single nucleotide polymorphisms in high linkage disequilibrium (r 2=0.86) with each other to be the strongest signals for PR (rs10428132, ß=-4.74, P=1.52×10-14) and QRS intervals (rs6599251, QRS ß=-0.73; P=1.2×10-4), respectively. Although these variants were not associated with SCN5A or SCN10A expression in human atrial tissue (n=490), they were in high linkage disequilibrium (r 2≥0.72) with a common SCN10A missense variant, rs6795970 (V1073A). In total, we identified 7 missense variants, 4 of which (I962V, P1045T, V1073A, and L1092P) were associated with cardiac conduction. These 4 missense variants cluster in the cytoplasmic linker of the second and third domains of the SCN10A protein and together form 6 common haplotypes. Using cellular electrophysiology, we found that haplotypes associated with shorter PR intervals had a significantly larger percentage of late current compared with wild-type (I962V+V1073A+L1092P, 20.2±3.3%, P=0.03, and I962V+V1073A, 22.4±0.8%, P=0.0004 versus wild-type 11.7±1.6%), and the haplotype associated with the longest PR interval had a significantly smaller late current percentage (P1045T, 6.4±1.2%, P=0.03). CONCLUSIONS: Our findings suggest an association between genetic variation in SCN10A, the late sodium current, and alterations in cardiac conduction.

Dietary sodium intake among US adults with hypertension, 1999-2012.

OBJECTIVE: Excess sodium consumption has strong links with hypertension and cardiovascular disease with Food and Drug Association calling to limit sodium intake. However, little is known regarding the trends of sodium intake among hypertensive patients in the United States. METHODS: Data from The National Health and Nutrition Examination Survey (1999-2012) were used to identify adults older than 20 years with self-reported hypertension. Sodium intake was measured through 24-h dietary recall. Linear regression was used to assess the time trends of sodium intake. RESULTS: Between the years of 1999 and 2012, sodium consumption increased 14.2% among all adults with hypertension (P = 0.012). The increase was seen in both sexes (by 13.3%, P = 0.023 for male, and by 12.1%, P = 0.015 for female). A significant increase was seen in the amount of sodium consumption among Hispanic (by 26.2%, P = 0.021) and African-American (by 20%, P = 0.031) participants, but not among non-Hispanic whites (by 2%, P = 0.096) during the study period. Participants with higher level of education (3487 ±â€Š1678 vs. 3230 ±â€Š1785 mg, P = 0.002) and household income (3527 ±â€Š1770 vs. 3301 ±â€Š1726 mg, P = 0.009) were found to consume more sodium, which remained significant after adjustment for age. CONCLUSION: Sodium intake has increased over the last two decades among individuals with hypertension. The increase was especially marked for Hispanics and African-Americans. Improved population-based interventions, including more effective strategies and aggressive approaches to reduce the sodium consumption among hypertensive adults, are needed.

Suicidal ideation among adults with cardiovascular disease: The National Health and Nutrition Examination Survey.

OBJECTIVE: Previous studies have shown a possible link between cardiovascular disease (CVD) and suicidal ideation (SI). However, limited information exists regarding the association between different subtypes of CVD and SI and the role of depression. METHODS: Data were used from the National Health and Nutrition Examination Survey for cycles 2009-2010 and 2011-2012. SI was assessed by item 9 of the Patient Health Questionnaire 9. Data regarding sociodemographic factors, and comorbid conditions were collected and examined as potential correlates. Logistic regression analyses were used to examine the relationship between CVD and subtypes and suicidal ideation. RESULTS: Among a total of 11,678 participants, suicidal ideation was significantly higher among patients with CVD compared to participants without a history of CVD (5.4% vs 3.6%, P<0.001). A subset of patients with CVD with a history of congestive heart failure (CHF) and prior myocardial infarction (MI) had the highest percentage of SI (10.6%). The association between CVD and SI remained significant after adjusting for baseline characteristics and associated comorbidities including depression (OR 1.40, 95% CI 1.10-2.09, P=0.006). CONCLUSION: CVD is an independent risk factor for SI. The identification of a subset of patients with CVD at greatest risk of SI underlines the importance of screening in this vulnerable population.

Diminished PRRX1 Expression Is Associated With Increased Risk of Atrial Fibrillation and Shortening of the Cardiac Action Potential.

BACKGROUND: Atrial fibrillation (AF) affects over 33 million individuals worldwide. Genome-wide association studies have identified at least 30 AF loci, but the mechanisms through which individual variants lead to altered disease risk have remained unclear for the majority of these loci. At the 1q24 locus, we hypothesized that the transcription factor PRRX1 could be a strong candidate gene as it is expressed in the pulmonary veins, a source of AF in many individuals. We sought to identify the molecular mechanism, whereby variation at 1q24 may lead to AF susceptibility. METHODS AND RESULTS: We sequenced a ≈158 kb region encompassing PRRX1 in 962 individuals with and without AF. We identified a broad region of association with AF at the 1q24 locus. Using in silico prediction and functional validation, we identified an enhancer that interacts with the promoter of PRRX1 in cells of cardiac lineage. Within this enhancer, we identified a single-nucleotide polymorphism, rs577676, which alters enhancer activity in a mouse atrial cell line and in embryonic zebrafish and differentially regulates PRRX1 expression in human left atria. We found that suppression of PRRX1 in human embryonic stem cell-derived cardiomyocytes and embryonic zebrafish resulted in shortening of the atrial action potential duration, a hallmark of AF. CONCLUSIONS: We have identified a functional genetic variant that alters PRRX1 expression, ultimately resulting in electrophysiological alterations in atrial myocytes that may promote AF.

Left Ventricular Mechanical Support with the Impella during Extracorporeal Membrane Oxygenation.

Background: Venoarterial extracorporeal membrane oxygenation (ECMO) provides systemic arterial support without directly unloading the left heart, which causes an elevated left ventricular (LV) pressure. The aim of the present study was to investigate the adjunctive application of the Impella device for LV unloading in patients during ECMO. Methods: This retrospective cohort study included patients who received Impella support in addition to venoarterial ECMO between April 2012 and December 2015. ECMO cannulation was performed peripherally or centrally, while the Impella device was surgically inserted into the femoral artery or the right axillary artery. Results: Among 62 patients, 10 (16.1%) received an Impella device during ECMO support. Following Impella support, right atrial pressure improved from a median of 18 (IQR, 14-24) mmHg to 13 (IQR, 10-15) mmHg and pulmonary wedge pressure improved from 30 (IQR, 26-35) mmHg to 16 (IQR, 12-19) mmHg in all the patients (p value < 0.001). Follow-up transthoracic echocardiograms (n = 6) showed a median decrease of 0.8 cm in LV end-diastolic volume (p value = 0.021). There were 5 (50%) in-hospital deaths due to sustained brain injury (n = 3) and refractory cardiogenic shock (n = 2). The remaining 5 patients were discharged and successfully bridged to more permanent LV assist device (n = 2) or heart transplantation (n = 3). Conclusion: The findings of the present study indicate that the application of the Impella device during ECMO support is effective in LV unloading and confers optimal hemodynamic support.

Chordae Tendineae Rupture in the United States: Trends of Outcomes, Costs and Surgical Interventions.

OBJECTIVES: To describe national trends in the incidence and outcomes of patients with chordae tendineae rupture (CTR). METHODS: Patients who were diagnosed with CTR between 2000 and 2012 were identified in National (Nationwide) Inpatient Sample (NIS) registry. CTR was defined using validated International Classification of Diseases, 9th Edition, Clinical Modification diagnosis (ICD9-CM) codes. Results: A total of 37,287 (14,833 mitral valve repair, 7780 mitral valve replacement) CTR cases were identified. Overall, in-hospital mortality in CTR decreased by 3% from 2000 to 2012 (P < 0.001). From 2000 to 2012, the rate of mitral valve repair increased from 27.2% to 46.4%, (P < 0.001) with a concurrent decrease in the rate of mitral valve replacement (from 27.8 to 17.7%, P < 0.001). After multivariate adjustment, patient age (OR = 1.04, 95% CI 1.03-1.06, P < 0.001), congestive heart failure (CHF) (OR = 2.08, 95% CI 1.19-3.64, P = 0.01), myocardial infarction (MI) (OR = 3.58, 95% CI 2.10-6.11, P < 0.001), Deyo/Charlson comorbidity index (OR = 1.23, 95% CI 1.07-1.41, P < 0.003) and use of the intra aortic balloon pump (IABP) (OR = 4.81 95% CI 2.71-8.55, P < 0.001) were found to be independently associated with greater odds of mortality in these patients. Additionally, mitral valve replacement was significantly associated with higher costs of hospitalization (coefficient 15693, 95% CI 12638-18749, P < 0.001)Conclusion: Mitral valve repair is associated with reduced inpatient mortality and costs compared with mitral valve replacement. A substantial increase in the percentage of cases undergoing mitral valve repair with a concurrent decrease in cases undergoing mitral valve replacement were observed. Increasing age and comorbidity index, history of CHF and MI, and use of IABP were identified as factors that could increase the risk of mortality in patients with CTR.

Extracorporeal Membrane Oxygenation in Massive Pulmonary Embolism.

BACKGROUND: Extracorporeal Membrane Oxygenation (ECMO) has been suggested for cardiopulmonary support in patients with massive pulmonary embolism (PE) refractory to other treatment or as bridging to embolectomy. The survival benefit from ECMO in patients with massive PE remains unclear. METHODS: Here, we describe 5 cases in which ECMO was used as cardiopulmonary support following massive near-fatal pulmonary embolism. RESULTS: The overall mortality in patients with massive PE that received ECMO support was 40%. Death occurred secondary to ECMO-related complication in one case and due to inability to maintain adequate cerebral perfusion despite ECMO support in the second case. CONCLUSIONS: ECMO can be considered as a treatment modality for patients with massive PE.

Impact of Hospital Teaching Status on Mortality, Length of Stay and Cost Among Patients With Cardiac Arrest in the United States.

Limited data exist regarding the in-hospital outcomes in patients with cardiac arrest (CA) in teaching versus nonteaching hospital settings. Using the Nationwide (National) Inpatient Sample (2008 to 2012), 731,107 cases of CA were identified using International Classification of Diseases, Ninth Edition codes. Among these patients, 348,368 (47.6%) were managed in teaching hospitals and 376,035 (51.4%) in nonteaching hospitals. Patients in teaching hospitals with CA were younger (62.42 vs 68.08 years old), had less co-morbidities (p <0.001), were less likely to be white (54.6% vs 65.5%) and more likely to be uninsured (9.1% vs 7.6%). Mortality in patients with CA was significantly lower in teaching hospitals than in nonteaching hospitals (55.3% vs 58.8%; all p <0.001). The mortality remained significantly lower after adjusting for baseline patient and hospital characteristics (odds ratio 0.917, CI 0.899 to 0.937, p <0.001). However, the survival benefit was no longer present after adjusting for in-hospital procedures (OR 0.997, CI 0.974 to 1.02, p = 0.779). In conclusion, teaching status of the hospital was associated with decreased in-hospital mortality in patients with CA. The differences in mortality disappeared after adjusting for in-hospital procedures, indicating that routine application of novel therapeutic methods in patients with CA in teaching hospitals could translate into improved survival outcomes.

Discovery and validation of sub-threshold genome-wide association study loci using epigenomic signatures.

Genetic variants identified by genome-wide association studies explain only a modest proportion of heritability, suggesting that meaningful associations lie 'hidden' below current thresholds. Here, we integrate information from association studies with epigenomic maps to demonstrate that enhancers significantly overlap known loci associated with the cardiac QT interval and QRS duration. We apply functional criteria to identify loci associated with QT interval that do not meet genome-wide significance and are missed by existing studies. We demonstrate that these 'sub-threshold' signals represent novel loci, and that epigenomic maps are effective at discriminating true biological signals from noise. We experimentally validate the molecular, gene-regulatory, cellular and organismal phenotypes of these sub-threshold loci, demonstrating that most sub-threshold loci have regulatory consequences and that genetic perturbation of nearby genes causes cardiac phenotypes in mouse. Our work provides a general approach for improving the detection of novel loci associated with complex human traits.

A novel trafficking-defective HCN4 mutation is associated with early-onset atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia, and a recent genome-wide association study identified the hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) as a novel AF susceptibility locus. HCN4 encodes for the cardiac pacemaker channel, and HCN4 mutations are associated with familial sinus bradycardia and AF. OBJECTIVE: The purpose of this study was to determine whether novel variants in the coding region of HCN4 contribute to the susceptibility for AF. METHODS: We sequenced the coding region of HCN4 for novel variants from 527 cases with early-onset AF from the Massachusetts General Hospital AF Study and 443 referents from the Framingham Heart Study. We used site-directed mutagenesis, cellular electrophysiology, immunocytochemistry, and confocal microscopy to functionally characterize novel variants. RESULTS: We found the frequency of novel coding HCN4 variants was 2-fold greater for individuals with AF (7 variants) compared to the referents (3 variants). We determined that of the 7 novel HCN4 variants in our AF cases, 1 (p.Pro257Ser, located in the amino-terminus adjacent to the first transmembrane spanning domain) did not traffic to cell membrane, whereas the remaining 6 were not functionally different from wild type. In addition, the 3 novel variants in our referents did not alter function compared to wild-type. Coexpression studies showed that the p.Pro257Ser mutant channel failed to colocalize with the wild-type HCN4 channel on the cell membrane. CONCLUSION: Our findings are consistent with HCN4 haploinsufficiency as the likely mechanism for early-onset AF in the p.Pro257Ser carrier.

Gene expression and genetic variation in human atria.

BACKGROUND: The human left and right atria have different susceptibilities to develop atrial fibrillation (AF). However, the molecular events related to structural and functional changes that enhance AF susceptibility are still poorly understood. OBJECTIVE: The purpose of this study was to characterize gene expression and genetic variation in human atria. METHODS: We studied the gene expression profiles and genetic variations in 53 left atrial and 52 right atrial tissue samples collected from the Myocardial Applied Genomics Network (MAGNet) repository. The tissues were collected from heart failure patients undergoing transplantation and from unused organ donor hearts with normal ventricular function. Gene expression was profiled using the Affymetrix GeneChip Human Genome U133A Array. Genetic variation was profiled using the Affymetrix Genome-Wide Human SNP Array 6.0. RESULTS: We found that 109 genes were differentially expressed between left and right atrial tissues. A total of 187 and 259 significant cis-associations between transcript levels and genetic variants were identified in left and right atrial tissues, respectively. We also found that a single nucleotide polymorphism at a known AF locus, rs3740293, was associated with the expression of MYOZ1 in both left and right atrial tissues. CONCLUSION: We found a distinct transcriptional profile between the right and left atrium and extensive cis-associations between atrial transcripts and common genetic variants. Our results implicate MYOZ1 as the causative gene at the chromosome 10q22 locus for AF.

'Scheduled' dosing of lornoxicam provides analgesia superior to that provided by 'on request' dosing following craniotomy.

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the efficacy of 'scheduled' analgesia with analgesia 'on request in patients after craniotomy. PATIENTS AND METHODS: We performed a prospective randomized study comparing 'scheduled' analgesia with analgesia 'on request' on 126 patients aged 16-70 years undergoing craniotomy for a variety of reasons. Patients were randomized to one of two groups; group 1 (68 patients) received lornoxicam 'on request', and group 2 (58 patients) received 8 mg of lornoxicam preoperatively, immediately after intubation, then 8 mg again 6-8 h after the first injection and 8 mg repeated every 8 h for 48 h postoperatively. Subgroup analysis was performed for patients with supratentorial and infratentorial craniotomy. We measured pain scores (visual analogue scale), mean blood pressure and heart rate at 6, 18, 30, 42 and 54 h after surgery and compared differences in these parameters between groups and amongst subgroups. RESULTS AND DISCUSSION: Group 1 visual analogue pain scale scores were significantly higher than those in group 2 (P < 0.05). Group 1 patients with infratentorial craniotomy showed higher pain scores than supratentorial craniotomy patients (P < 0.05). No significant differences were observed in mean blood pressure between groups and subgroups (P > 0.05). We found no correlation between visual analogue scale scores, mean blood pressure and heart rate (P > 0.05). CONCLUSION: 'Scheduled' analgesia with lornoxicam was more effective for treating post-craniotomy pain than 'on request' analgesia with lornoxicam.