325 research outputs found
MyD88-dependent interplay between myeloid and endothelial cells in the initiation and progression of obesity-associated inflammatory diseases.
Low-grade systemic inflammation is often associated with metabolic syndrome, which plays a critical role in the development of the obesity-associated inflammatory diseases, including insulin resistance and atherosclerosis. Here, we investigate how Toll-like receptor-MyD88 signaling in myeloid and endothelial cells coordinately participates in the initiation and progression of high fat diet-induced systemic inflammation and metabolic inflammatory diseases. MyD88 deficiency in myeloid cells inhibits macrophage recruitment to adipose tissue and their switch to an M1-like phenotype. This is accompanied by substantially reduced diet-induced systemic inflammation, insulin resistance, and atherosclerosis. MyD88 deficiency in endothelial cells results in a moderate reduction in diet-induced adipose macrophage infiltration and M1 polarization, selective insulin sensitivity in adipose tissue, and amelioration of spontaneous atherosclerosis. Both in vivo and ex vivo studies suggest that MyD88-dependent GM-CSF production from the endothelial cells might play a critical role in the initiation of obesity-associated inflammation and development of atherosclerosis by priming the monocytes in the adipose and arterial tissues to differentiate into M1-like inflammatory macrophages. Collectively, these results implicate a critical MyD88-dependent interplay between myeloid and endothelial cells in the initiation and progression of obesity-associated inflammatory diseases
Identifying predictable foraging habitats for a wide-ranging marine predator using ensemble ecological niche models
Aim
Ecological niche modelling can provide valuable insight into species' environmental preferences and aid the identification of key habitats for populations of conservation concern. Here, we integrate biologging, satellite remote-sensing and ensemble ecological niche models (EENMs) to identify predictable foraging habitats for a globally important population of the grey-headed albatross (GHA) Thalassarche chrysostoma.
Location
Bird Island, South Georgia; Southern Atlantic Ocean.
Methods
GPS and geolocation-immersion loggers were used to track at-sea movements and activity patterns of GHA over two breeding seasons (n = 55; brood-guard). Immersion frequency (landings per 10-min interval) was used to define foraging events. EENM combining Generalized Additive Models (GAM), MaxEnt, Random Forest (RF) and Boosted Regression Trees (BRT) identified the biophysical conditions characterizing the locations of foraging events, using time-matched oceanographic predictors (Sea Surface Temperature, SST; chlorophyll a, chl-a; thermal front frequency, TFreq; depth). Model performance was assessed through iterative cross-validation and extrapolative performance through cross-validation among years.
Results
Predictable foraging habitats identified by EENM spanned neritic ( 0.5 mg mā3) and frequent manifestation of mesoscale thermal fronts. Our results confirm previous indications that GHA exploit enhanced foraging opportunities associated with frontal systems and objectively identify the APFZ as a region of high foraging habitat suitability. Moreover, at the spatial and temporal scales investigated here, the performance of multi-model ensembles was superior to that of single-algorithm models, and cross-validation among years indicated reasonable extrapolative performance.
Main conclusions
EENM techniques are useful for integrating the predictions of several single-algorithm models, reducing potential bias and increasing confidence in predictions. Our analysis highlights the value of EENM for use with movement data in identifying at-sea habitats of wide-ranging marine predators, with clear implications for conservation and management
Nitrated Fibrinogen is A Biomarker of Oxidative Stress in Venous Thromboembolism
The pathogenesis of venous thromboembolism (VTE) is linked to inflammation and oxidant production, although specific markers for these pathways with pathological relevance to VTE have not been explored. The coagulant protein fibrinogen is posttranslationally modified by nitric oxide-derived oxidants to nitrated fibrinogen in both acute and chronic inflammatory states. Therefore, nitrated fibrinogen may serve as a marker of inflammation and oxidative stress in VTE. To test this hypothesis we enrolled subjects (n=251) presenting with suspected VTE at the University of Pennsylvania Hospital emergency department, 50 (19.9%) of whom were positive by imaging or 90-day follow-up. Mean nitrated fibrinogen was elevated in VTE-positive (62.7 nM, 95% CI 56.6ā68.8) compared to VTE-negative patients (54.2 nM, 95% CI 51.4ā57.1; P\u3c0.01). Patients in the highest quartile of nitrated fibrinogen had an increased risk of VTE compared with patients in the lowest quartile (OR 3.30; 95% CI 1.25ā8.68; P\u3c0.05). This risk persisted after univariate adjustment for age, active cancer, and recent surgery, but not after multivariate adjustment. Mean fibrinogen levels measured either by the Clauss assay or by ELISA were not different between VTE-negative and VTE-positive patients. These data indicate that nitrated fibrinogen is an oxidative risk marker in VTE, providing a novel mechanistic link between oxidant production, inflammation, and VTE
Intestinal Microbiota-Dependent Phosphatidylcholine Metabolites, Diastolic Dysfunction, and Adverse Clinical Outcomes in Chronic Systolic Heart Failure
Background: Trimethylamine-N-oxide (TMAO) has been linked to increased cardiovascular risk. We aimed to determine the prognostic value of TMAO and its dietary precursors, choline and betaine, in heart failure (HF). Methods and Results: In 112 patients with chronic systolic HF with comprehensive echocardiographic evaluation, we measured plasma TMAO, choline, and betaine by mass spectrometry. Median (interquartile range) TMAO levels, choline, and betaine levels were 5.8 (3.6ā12.1) Ī¼mol/L, 10.9 (8.4ā14.0) Ī¼mol/L, and 43.8 (37.1ā53.0) Ī¼mol/L, respectively, and were correlated with each other (all P \u3c .0001 for both). TMAO levels were significantly higher in patients with diabetes mellitus (9.4 [4.9ā13.2] vs 4.8 [3.4ā9.8] Ī¼mol/L; P = .005) and in subjects with New York Heart Association functional class III or greater (7.0 [4.7ā14.8] vs 4.7 [3.4ā11.3] Ī¼mol/L; P = .02). Elevated TMAO, choline, and betaine levels were each associated with higher plasma N-terminal proāB-type natriuretic peptide (NT-proBNP) levels and more advanced left ventricular diastolic dysfunction, but not systolic dysfunction or inflammatory and endothelial biomarkers. Higher choline (hazard ratio [HR] 1.64, 95% CI 1.22ā2.20; P = .001), betaine (HR 1.51, 95% CI 1.10ā2.08; P = .01), and TMAO (HR 1.48, 95% CI 1.10ā1.96; P = .01) predicted increased risk for 5-year adverse clinical events (death/transplantation). Only higher TMAO levels predicted incident adverse clinical events independently from age, estimated glomerular filtration rate, mitral E/septal Ea, and NT-proBNP levels (HR 1.46, 95% CI 1.03ā2.14; P = .03). Conclusion: Elevated plasma TMAO, choline, and betaine levels are each associated with more advanced left ventricular diastolic dysfunction and portend poorer long-term adverse clinical outcomes in chronic systolic HF. However, only higher plasma TMAO was associated with poor prognosis after adjustment for cardiorenal indices
Immunoglobulins Against Tyrosine-Nitrated Epitopes in Coronary Artery Disease
BackgroundāSeveral lines of evidence support a pathophysiological role of immunity in atherosclerosis. Tyrosine-nitrated proteins, a footprint of oxygen- and nitrogen-derived oxidants generated by cells of the immune system, are enriched in atheromatous lesions and in circulation of patients with coronary artery disease (CAD). However, the consequences of possible immune reactions triggered by the presence of nitrated proteins in subjects with clinically documented atherosclerosis have not been explored. Methods and ResultsāSpecific immunoglobulins that recognize 3-nitrotyrosine epitopes were identified in human lesions, as well as in circulation of patients with CAD. The levels of circulating immunoglobulins against 3-nitrotyrosine epitopes were quantified in patients with CAD (n=374) and subjects without CAD (non-CAD controls, n=313). A 10-fold increase in the mean level of circulating immunoglobulins against protein-bound 3-nitrotyrosine was documented in patients with CAD (3.75Ā±1.8 Ī¼g antibody Eq/mL plasma versus 0.36Ā±0.8 Ī¼g antibody Eq/mL plasma), and was strongly associated with angiographic evidence of significant CAD. ConclusionsāThe results of this cross-sectional study suggest that posttranslational modification of proteins via nitration within atherosclerotic plaque-laden arteries and in circulation serve as neo-epitopes for the elaboration of immunoglobulins, thereby providing an association between oxidant production and the activation of the immune system in CAD
Trimethylamine-N-Oxide, a Metabolite Associated with Atherosclerosis, Exhibits Complex Genetic and Dietary Regulation
SummaryCirculating trimethylamine-N-oxide (TMAO) levels are strongly associated with atherosclerosis. We now examine genetic, dietary, and hormonal factors regulating TMAO levels. We demonstrate that two flavin mono-oxygenase family members, FMO1 and FMO3, oxidize trimethylamine (TMA), derived from gut flora metabolism of choline, to TMAO. Further, we show that FMO3 exhibits 10-fold higher specific activity than FMO1. FMO3 overexpression in mice significantly increases plasma TMAO levels while silencing FMO3 decreases TMAO levels. In both humans and mice, hepatic FMO3 expression is reduced in males compared to females. In mice, this reduction in FMO3 expression is due primarily to downregulation by androgens. FMO3 expression is induced by dietary bile acids by a mechanism that involves the farnesoid X receptor (FXR), a bile acid-activated nuclear receptor. Analysis of natural genetic variation among inbred strains of mice indicates that FMO3 and TMAO are significantly correlated, and TMAO levels explain 11% of the variation in atherosclerosis
Nitrated Fibrinogen is A Biomarker of Oxidative Stress in Venous Thromboembolism
The pathogenesis of venous thromboembolism (VTE) is linked to inflammation and oxidant production, although specific markers for these pathways with pathological relevance to VTE have not been explored. The coagulant protein fibrinogen is posttranslationally modified by nitric oxide-derived oxidants to nitrated fibrinogen in both acute and chronic inflammatory states. Therefore, nitrated fibrinogen may serve as a marker of inflammation and oxidative stress in VTE. To test this hypothesis we enrolled subjects (n=251) presenting with suspected VTE at the University of Pennsylvania Hospital emergency department, 50 (19.9%) of whom were positive by imaging or 90-day follow-up. Mean nitrated fibrinogen was elevated in VTE-positive (62.7 nM, 95% CI 56.6ā68.8) compared to VTE-negative patients (54.2 nM, 95% CI 51.4ā57.1; P\u3c0.01). Patients in the highest quartile of nitrated fibrinogen had an increased risk of VTE compared with patients in the lowest quartile (OR 3.30; 95% CI 1.25ā8.68; P\u3c0.05). This risk persisted after univariate adjustment for age, active cancer, and recent surgery, but not after multivariate adjustment. Mean fibrinogen levels measured either by the Clauss assay or by ELISA were not different between VTE-negative and VTE-positive patients. These data indicate that nitrated fibrinogen is an oxidative risk marker in VTE, providing a novel mechanistic link between oxidant production, inflammation, and VTE
Gender Specific Differences in the Pros and Cons of Smoking among Current Smokers in Eastern Kentucky: Implications for Future Smoking Cessation Interventions
This study investigated gender differences in the perceived āprosā and āconsā of smoking using the constructs of decisional balance (DB) and stage of change from the Transtheoretical Model. The population distribution for stage of change among a population-based, cross-sectional survey of 155 current smokers over 40 years was: precontemplation (22.6%), contemplation (41.9%), preparation (35.5%). Results of stepwise regression models indicated significant gender differences in DB were in the preparation stage of change; scores on the DB measure increased 3.94 points (95% CI: 1.94, 5.93) for male smokers. Interventions targeting the āprosā and āconsā of smoking may need to be gender specific
Wild Blueberries 1999 CSREES Progress Reports
The 1999 edition of the Wild Blueberries CSREES Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
1. Effects of QF Processing on Microbiological Quality of Maine Wild Blueberries
2. Separation of Maggot-Infested Blueberries in the IQF Processing Line
3. Determination of Pesticide Residue Levels in Fresh and Processed Wild Blueberries
4. Control Tactics for Blueberry Pest Insects
5. IPM Strategies
6. Biology and Ecology of Blueberry Pest Insects
7. Survey of Stem Blight and Leaf Spot Diseases in Lowbush Blueberry Fields
8. Phosphorus/Nitrogen Fertilizer Ratio
9. Effect of Fertilizer Timing on Lowbush Blueberry Growth and Productivity
10. Effect of Soil pH on Nutrient Uptake
11. Effect of Boron Application Methods on Boron Uptake in Lowbush Blueberries
12. Effect of Nutri-Phite P+K on growth and yield of lowbush blueberry
13. Effect of Crop-Set on growth and yield of lowbush blueberry
14. Crop year fertilization of lowbush blueberry
15. Alternative Methods of Grass Control
16. Cultural Weed Management Using pH
17. Investigation of Hexazinone Alternatives for Weed Control
18. Comparison of Sulfosate and Glyphosate for Weed Control
19. Evaluation of VC1447 for Weed Control in Wild blueberries
20. Blueberry/ Cranberry Extension Education Program in 1999
21. Effect of Rate, Formulation and Application Method on Efficacy and Phytotoxicity of Granular Hexazinone in Wild Blueberry Fields
22. 1999 Fungicide Evaluation Field Trial
23. 1999 Hexazinone Groundwater Survey Pollination
24. Sustainable Pollination of Wild Blueberr
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