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Showing 461–480 of 2058 publications.
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Bubb, Kristen J.; Ravindran, Dhanya; Cartland, Si; Finemore, Meghan; Clayton, Zoe E.; Tsang, Michael; Tang, Owen; Kavurma, Mary M.; Patel, Sanjay; Figtree, Gemma A.Aims/Hypothesis: Peripheral arterial disease (PAD) is a major burden, resulting in limb claudication, repeated surgical interventions and amputation. There is an unmet need for improved medical management of PAD that improves quality of life, maintains activities of daily life and reduces complications. Nitric oxide (NO)/redox balance is a key regulator of angiogenesis. We have previously shown beneficial effects of a ?<inf>3</inf> adrenergic receptor (?<inf>3</inf>AR) agonist on NO/redox balance. We hypothesized that ?<inf>3</inf>AR stimulation would have therapeutic potential in PAD by promoting limb angiogenesis. Methods: The effect of the ?<inf>3</inf>AR agonist CL 316,243 (11,000nmol/L in vitro, 1mg/kg/day s. c) was tested in established angiogenesis assays with human endothelial cells and patient-derived endothelial colony forming cells. Post-ischemia reperfusion was determined in streptozotocin and/or high fat diet-induced diabetic and non-diabetic mice in vivo using the hind limb ischemia model. Results: CL 316,243 caused accelerated recovery from hind limb ischemia in non-diabetic and type 1 and 2 diabetic mice. Increased eNOS activity and decreased superoxide generation were detected in hind limb ischemia calf muscle from CL 316, 243 treated mice vs. controls. The protective effect of CL 316,243 in diabetic mice was associated with >50% decreases in eNOS glutathionylation and nitrotyrosine levels. The ?<inf>3</inf>AR agonist directly promoted angiogenesis in endothelial cells in vitro. These pro-angiogenic effects were ?<inf>3</inf>AR and NOS-dependent. Conclusion/Interpretation: ?<inf>3</inf>AR stimulation increased angiogenesis in diabetic ischemic limbs, with demonstrable improvements in NO/redox balance and angiogenesis elicited by a selective agonist. The orally available ?<inf>3</inf>AR agonist, Mirabegron, used for overactive bladder syndrome, makes translation to a clinical trial by repurposing of a ?<inf>3</inf>AR agonist to target PAD immediately feasible. Copyright 2021 Bubb, Ravindran, Cartland, Finemore, Clayton, Tsang, Tang, Kavurma, Patel and Figtree.
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Galougahi, Keyvan Karimi; Shlofmitz, Evan S.; Jeremias, Allen; Gogia, Shawnbir S.; Kirtane, Ajay Jayant; Hill, Jonathan Michael; Karmpaliotis, Dimitri; Mintz, Gary S.; Maehara, Akiko; Stone, Gregg Whitney; Shlofmitz, Richard Alan; Ali, Ziad A.Purpose of Review: Moderate or severe calcification is present in approximately one third of coronary lesions in patients with stable ischemic heart disease and acute coronary syndromes and portends unfavorable procedural results and long-term outcomes. In this review, we provide an overview on the state-of-the-art in evaluation and treatment of calcified coronary lesions. Recent Findings: Intravascular imaging (intravascular ultrasound or optical coherence tomography) can guide percutaneous coronary intervention of severely calcified lesions. New technologies such as orbital atherectomy and intravascular lithotripsy have significantly expanded the range of available techniques to effectively modify coronary calcium and facilitate stent expansion. Summary: Calcium fracture improves lesion compliance and is essential to optimize stent implantation. Intravascular imaging allows for detailed assessment of patterns and severity of coronary calcium that are integrated into scoring systems to predict stent expansion, identifying which lesions require atherectomy for lesion modification. Guided by intravascular imaging, older technologies such as rotational atherectomy and excimer laser can be incorporated with newer technologies such as orbital atherectomy and intravascular lithotripsy into an algorithmic approach for the safe and effective treatment of patients with heavily calcified coronary lesions. 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
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Lowres, Nicole; Suwanwela, Nijasri Charnnarong; Chutinet, Aurauma; Freedman, Ben Ben[No abstract available]
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Thompson, Peter Lindsay[No abstract available]
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Liu, Chiachi; Zhang, Yunjia; Makris, Angela; Rasmussen, Helge H.; Hennessy, AnnemarieContext: Reduced Na+-K+ pump activity is widely reported in preeclampsia and may be caused by a reversible oxidative modification that is a novel pathological feature of preeclampsia. Objective: This work aims to determine whether ? 1 subunit (GSS-? 1) protein glutathionylation of the Na+-K + pump occurs in preeclampsia. Methods: The GSS-?1 of the Na+-K+ pump and its subunit expression in human placentas were compared between women with healthy pregnancies and women with preeclampsia. Human placental samples of pregnant women with preeclampsia (n = 11, mean gestational age 36.5 weeks) were used to examine the GSS-? 1 of the Na+-K+ pump, compared to healthy pregnancies (n = 11, mean gestational age 39 weeks). The potential pathogenetic role of GSS-? 1-mediated Na+-K+ pump dysfunction in preeclampsia was investigated. Results: Protein expression of the ? 1 subunit was unchanged in placentas from women with preeclampsia vs those with normotensive pregnancies. Preeclamptic placentas had a significantly increased GSS-? 1 of the Na+-K+ pump compared to those from healthy pregnancies, and this was linked to a decrease in ? 1/? 1 subunit coimmunoprecipitation. The cytosolic p47phox nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase subunit and its coimmunoprecipitation with the ? 1 Na+-K+ pump subunit was increased in preeclamptic placentas, thus implicating NADPH oxidase-dependent pump inhibition. Conclusions: The high level of ? 1 pump subunit glutathionylation provides new insights into the mechanism of Na+-K+ pump dysfunction in preeclampsia. 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Zhang, Jennifer Qin Jing; Saravanabavan, Sayanthooran; Cheng, Kaiman; Raghubanshi, Aarya; Chandra, Ashley N.; Munt, Alexandra E.; Rayner, Benjamin Saul; Zhang, Yunjia; Chau, Katrina; Wong, Annette T.Y.; Rangan, Gopala K.Augmentation of endogenous nitric oxide (NO) synthesis, either by the classical L-arginine-NO synthase pathway, or the recently discovered entero-salivary nitrate-nitrite-NO system, may slow the progression of autosomal dominant polycystic kidney disease (ADPKD). To test this hypothesis, the expression of NO in human ADPKD cell lines (WT 9-7, WT 9-12), and the effect of L-arginine on an in vitro model of three-dimensional cyst growth using MDCK cells, was examined. In addition, groups of homozygous Pkd1RC/RC mice (a hypomorphic genetic ortholog of ADPKD) received either low, moderate or high dose sodium nitrate (0.1, 1 or 10 mmol/kg/day), or sodium chloride (vehicle; 10 mmol/kg/day), supplemented drinking water from postnatal month 1 to 9 (n = 12 per group). In vitro, intracellular NO, as assessed by DAF-2/DA fluorescence, was reduced by >70% in human ADPKD cell lines, and L-arginine and the NO donor, sodium nitroprusside, both attenuated in vitro cyst growth by up to 18%. In contrast, in Pkd1RC/RC mice, sodium nitrate supplementation increased serum nitrate/nitrite levels by ~25-fold in the high dose group (P<0.001), but kidney enlargement and percentage cyst area was not altered, regardless of dose. In conclusion, L-arginine has mild direct efficacy on reducing renal cyst growth in vitro, whereas long-term sodium nitrate supplementation was ineffective in vivo. These data suggest that the bioconversion of dietary nitrate to NO by the entero-salivary pathway may not be sufficient to influence the progression of renal cyst growth in ADPKD. : 2021 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Khandkar, Chinmay; Madhavan, Mahesh V.; Weaver, James C.; Celermajer, David S.; Galougahi, Keyvan KarimiThe atherothrombotic substrates for acute coronary syndromes (ACS) consist of plaque ruptures, erosions and calcified nodules, while the non-atherothrombotic etiologies, such as spontaneous coronary artery dissection, coronary artery spasm and coronary embolism are the rarer causes of ACS. The purpose of this comprehensive review is to (1) summarize the histopathologic insights into the atherothrombotic plaque subtypes in acute ACS from postmortem studies; (2) provide a brief overview of atherogenesis, while mainly focusing on the events that lead to plaque destabilization and disruption; (3) summarize mechanistic data from clinical studies that have used intravascular imaging, including high-resolution optical coherence tomography, to assess culprit plaque morphology and its underlying pathobiology, especially the newly described role of innate and adaptive immunity in ACS secondary to plaque erosion; (4) discuss the utility of intravascular imaging for effective treatment of patients presenting with ACS by percutaneous coronary intervention; and (5) discuss the opportunities that these mechanistic and imaging insights may provide for more individualized treatment of patients with ACS. 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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Sawant, Sonia; Tucker, Bradley; Senanayake, Praween; Waters, David D.; Patel, Sanjay; Rye, Kerry Anne; Ong, Kwok Leung; Cochran, Blake J.Background: Relationships between dyslipidaemia and leukocyte counts have been investigated in several studies, demonstrating limited evidence of associations in humans. As such, studying a diverse range of cohorts will ensure evidence is robust. This study focused on investigating cross-sectional and longitudinal relationships in three large-scale cohorts. Methods: The cross-sectional analysis included a total of 27,566 participants with valid data on lipid measures and leukocyte counts from three study cohorts: National Health and Nutrition Survey (NHANES), Korean National Health and Nutrition Survey (KNHANES) and Treating to New Targets (TNT) trial. The longitudinal analysis included 9323 participants with valid data on lipid measures and leukocyte counts at baseline and one year with statin treatment. Associations between lipid levels and leukocyte counts were analysed by multivariable linear regression and adjusted for basic demographic and cardiovascular risk factors. Results: Cross-sectional data from NHANES demonstrated the association of lower high-density lipoprotein (HDL) cholesterol and higher triglycerides with higher leukocyte count (0.9% lower and 0.3% higher count per 10 mg/dL increase in HDL cholesterol and triglycerides respectively, both p < 0.001). Similar trends were found in TNT trial (both p < 0.001), but not in KNHANES. In the TNT trial, 10 mg/dL increase in triglycerides over one year was also associated with a 0.09 103/?L increase in leukocyte count over the same period. Conclusions: The findings of this study are consistent with those of previous human studies, supporting weak yet noteworthy associations between dyslipidaemia and leukocytosis. 2021 The Authors
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Peng, Kangyu; Salim, Malinda; Pelle, Joseph; Ramirez, Gisela; Boyd, Ben J.Liquid chromatography tandem mass spectrometry (LC/MS) and other mass spectrometric technologies have been widely applied for triacylglycerol profiling. One challenge for targeted identification of fatty acyl moieties that constitute triacylglycerol species in biological samples is the numerous combinations of 3 fatty acyl groups that can form a triacylglycerol molecule. Manual determination of triacylglycerol structures based on peak intensities and retention time can be highly inefficient and error-prone. To resolve this, we have developed TAILOR-MS, a Python (programming language) package that aims at assisting: (1) the generation of targeted LC/MS methods for triacylglycerol detection and (2) automating triacylglycerol structural determination and prediction. To assess the performance of TAILOR-MS, we conducted LC/MS triacylglycerol profiling of bovine milk and two infant formulas. Our results confirmed dissimilarities between bovine milk and infant formula triacylglycerol composition. Furthermore, we identified 247 triacylglycerol species and predicted the possible existence of another 317 in the bovine milk sample, representing one of the most comprehensive reports on the triacylglycerol composition of bovine milk thus far. Likewise, we presented here a complete infant formula triacylglycerol profile and reported >200 triacylglycerol species. TAILOR-MS dramatically shortened the time required for triacylglycerol structural identification from hours to seconds and performed decent structural predictions in the absence of some triacylglycerol constituent peaks. Taken together, TAILOR-MS is a valuable tool that can greatly save time and improve accuracy for targeted LC/MS triacylglycerol profiling.
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Brieger, David B.; Freedman, Ben Ben[No abstract available]
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Wachter, Rolf; Freedman, Ben Ben[No abstract available]
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Wild, Johannes; Jung, Rebecca; Knopp, Tanja; Efentakis, Panagiotis; Benaki, Dimitra C.; Grill, Alexandra; Wegner, Joanna; Molitor, Michael; Garlapati, Venkata S.; Rakova, Natalia; Mark Lajos; Marton, Adriana; Mikros, Emmanuel; Mzel, Tomas F.; Kossmann, Sabine; Rauh, Manfred; Nakano, Daisuke; Kitada, Kento; Luft, Friedrich C.; Waisman, Ari; Wenzel, Philip; Titze, Jens M.; Karbach, Susanne HelenaAim: Recent evidence suggests that arterial hypertension could be alternatively explained as a physiological adaptation response to water shortage, termed aestivation, which relies on complex multi-organ metabolic adjustments to prevent dehydration. Here, we tested the hypothesis that chronic water loss across diseased skin leads to similar adaptive water conservation responses as observed in experimental renal failure or high salt diet. Methods: We studied mice with keratinocyte-specific overexpression of IL-17A which develop severe psoriasis-like skin disease. We measured transepidermal water loss and solute and water excretion in the urine. We quantified glomerular filtration rate (GFR) by intravital microscopy, and energy and nitrogen pathways by metabolomics. We measured skin blood flow and transepidermal water loss (TEWL) in conjunction with renal resistive indices and arterial blood pressure. Results: Psoriatic animals lost large amounts of water across their defective cutaneous epithelial barrier. Metabolic adaptive water conservation included mobilization of nitrogen and energy from muscle to increase organic osmolyte production, solute-driven maximal anti-diuresis at normal GFR, increased metanephrine and angiotensin 2 levels, and cutaneous vasoconstriction to limit TEWL. Heat exposure led to cutaneous vasodilation and blood pressure normalization without parallel changes in renal resistive index, albeit at the expense of further increased TEWL. Conclusion: Severe cutaneous water loss predisposes psoriatic mice to lethal dehydration. In response to this dehydration stress, the mice activate aestivation-like water conservation motifs to maintain their body hydration status. The circulatory water conservation response explains their arterial hypertension. The nitrogen-dependency of the metabolic water conservation response explains their catabolic muscle wasting. 2021 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.
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Lowres, Nicole; Giskes, Katrina; Freedman, Ben Ben[No abstract available]
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Guan, Ivy A.; Williams, Kayla; Pan, Jolyn; Liu, XuyuThere has been tremendous progress in covalent inhibitors as evidenced by the ascent of innovative electrophilic warheads with suppressed non-specific reactivity but enhanced capacity for proximity-driven covalent reactions with nucleophilic residues in the targeted site. Kinases, a central player in cancers, autoimmune disorders and chronic diseases, represent a highly targeted class of enzymes by covalent inhibitors. However, innovative strategies to afford high selectivity in target recognition remain a pressing need. This minireview focuses on four promising strategies to achieve superior target selectivity through rational design of the covalent engagement. Special emphasis is placed on examples where the selectivity had arisen by complementing the reactivity of protein cysteines with electrophilic warheads specified for distinct covalent chemistry, or inspired from native electrophile signalling in cells. 2021 Wiley-VCH GmbH
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Vernon, Stephen Thomas; Tang, Owen; Kim, Taiyun; Chan, Adam S.; Kott, Katharine A.; Park, John; Hansen, Thomas S.; Koay, Yen Chin; Grieve, Stuart M.; OSullivan, John F.; Yang, Jean Yee Hwa; Figtree, Gemma A.Despite effective prevention programs targeting cardiovascular risk factors, coronary artery disease (CAD) remains the leading cause of death. Novel biomarkers are needed for improved risk stratification and primary prevention. To assess for independent associations between plasma metabolites and specific CAD plaque phenotypes we performed liquid chromatography mass-spec-trometry on plasma from 1002 patients in the BioHEART-CT study. Four metabolites were exam-ined as candidate biomarkers. Dimethylguanidino valerate (DMGV) was associated with presence and amount of CAD (OR) 1.41 (95% Confidence Interval [CI] 1.121.79, p = 0.004), calcified plaque, and obstructive CAD (p < 0.05 for both). The association with amount of plaque remained after adjustment for traditional risk factors, coefficient 0.17 (95% CI 0.020.32, p = 0.026). Glutamate was associated with the presence of non-calcified plaque, OR 1.48 (95% CI 1.092.01, p = 0.011). Phenyl-alanine was associated with amount of CAD, coefficient 0.33 (95% CI 0.040.62, p = 0.025), amount of calcified plaque, (coefficient 0.88, 95% CI 0.231.53, p = 0.008), and obstructive CAD, OR 1.84 (95% CI 1.013.31, p = 0.046). Trimethylamine N-oxide was negatively associated non-calcified plaque OR 0.72 (95% CI 0.530.97, p = 0.029) and the association remained when adjusted for traditional risk factors. In targeted metabolomic analyses including 53 known metabolites and controlling for a 5% false discovery rate, DMGV was strongly associated with the presence of calcified plaque, OR 1.59 (95% CI 1.262.01, p = 0.006), obstructive CAD, OR 2.33 (95% CI 1.593.43, p = 0.0009), and amount of CAD, coefficient 0.3 (95% CI 0.140.45, p = 0.014). In multivariate analyses the lipid and nucleotide metabolic pathways were both associated with the presence of CAD, after adjustment for traditional risk factors. We report novel associations between CAD plaque pheno-types and four metabolites previously associated with CAD. We also identified two metabolic pathways strongly associated with CAD, independent of traditional risk factors. These pathways war-rant further investigation at both a biomarker and mechanistic level. 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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Wang, Cuihua; Cheng, David; Jalali Motlagh, Negin; Kuellenberg, Enrico Giovanni; Wojtkiewicz, Gregory J.; Schmidt, Stephen Paul; Stocker, Roland; Chen, John W.Myeloperoxidase (MPO) is a key component of innate immunity but can damage tissues when secreted abnormally. We developed a new generation of a highly efficient MPO-activatable MRI probe (heMAMP) to report MPO activity. heMAMP has improved Gd stability compared to bis-5-HT-Gd-DTPA (MPO-Gd) and demonstrates no significant cytotoxicity. Importantly, heMAMP is more efficiently activated by MPO compared to MPO-Gd, 5HT-DOTA(Gd), and 5HT-DOTAGA-Gd. Molecular docking simulations revealed that heMAMP has increased rigidity via hydrogen bonding intramolecularly and improved binding affinity to the active site of MPO. In animals with subcutaneous inflammation, activated heMAMP showed a 2-3-fold increased contrast-to-noise ratio (CNR) compared to activated MPO-Gd and 4-10 times higher CNR compared to conventional DOTA-Gd. This increased efficacy was further confirmed in a model of unstable atherosclerotic plaque where heMAMP demonstrated a comparable signal increase and responsiveness to MPO inhibition at a 3-fold lower dosage compared to MPO-Gd, further underscoring heMAMP as a potential translational candidate. 2021 American Chemical Society. All rights reserved.
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Freedman, Ben Ben; Hindricks, Gerhard; Banerjee, Amitava; Baranchuk, Adri Marco; Ching, Chikeong; Du, Xin; Fitzsimons, D.; Healey, Jeff S.; Ikeda, Takanori; Lobban, Trudie C.A.; Mbakwem, Amam Chinyere; Narasimhan, Calambur; Neubeck, Lis; Noseworthy, Peter A.; Philbin, Daniel M.; Pinto, Fausto J.; Rwebembera, Joselyn; Schnabel, Renate B.; Svendsen, Jesper Hastrup; Aguinaga, Luis Enrique; Arbelo, Elena; Bm, Michael; Farhan, Hasan Ali; Hobbs, FD Richard; Martez-Rubio, Antonio; Militello, Claudio A.; Naik, Nitish; Noubiap, Jean Jacques; Perel, Pablo A.; Piiro, Daniel Jos Ribeiro, Antonio L.; St?pi?ska, JaninaThe World Heart Federation (WHF) commenced a Roadmap initiative in 2015 to reduce the global burden of cardiovascular disease and resultant burgeoning of healthcare costs. Roadmaps provide a blueprint for implementation of priority solutions for the principal cardiovascular diseases leading to death and disability. Atrial fibrillation (AF) is one of these conditions and is an increasing problem due to ageing of the worlds population and an increase in cardiovascular risk factors that predispose to AF. The goal of the AF roadmap was to provide guidance on priority interventions that are feasible in multiple countries, and to identify roadblocks and potential strategies to overcome them. Since publication of the AF Roadmap in 2017, there have been many technological advances including devices and artificial intelligence for identification and prediction of unknown AF, better methods to achieve rhythm control, and widespread uptake of smartphones and apps that could facilitate new approaches to healthcare delivery and increasing community AF awareness. In addition, the World Health Organisation added the non-vitamin K antagonist oral anticoagulants (NOACs) to the Essential Medicines List, making it possible to increase advocacy for their widespread adoption as therapy to prevent stroke. These advances motivated the WHF to commission a 2020 AF Roadmap update. Three years after the original Roadmap publication, the identified barriers and solutions were judged still relevant, and progress has been slow. This 2020 Roadmap update reviews the significant changes since 2017 and identifies priority areas for achieving the goals of reducing death and disability related to AF, particularly targeted at low-middle income countries. These include advocacy to increase appreciation of the scope of the problem; plugging gaps in guideline management and prevention through physician education, increasing patient health literacy, and novel ways to increase access to integrated healthcare including mHealth and digital transformations; and greater emphasis on achieving practical solutions to national and regional entrenched barriers. Despite the advances reviewed in this update, the task will not be easy, but the health rewards of implementing solutions that are both innovative and practical will be great. 2021 The Author(s).
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Kurup, Rahul; Galougahi, Keyvan Karimi; Figtree, Gemma A.; Misra, Ashish K.; Patel, SanjayColchicine, an inexpensive immunomodulatory drug used traditionally to treat gout and familial Mediterranean fever, is rapidly accumulating basic and clinical evidence for a therapeutic role in atherosclerotic cardiovascular disease. Its athero-protective properties are thought to be mainly related to its effect on tubulin polymerisation, enabling a broad range of effect on multiple atherosclerotic plaque cell types and cellular processes, including cell division, cell migration as well as pro-inflammatory cytokine and chemokine secretion. These properties indicate the potential to favourably affect all stages of atherosclerotic plaque development including formation, progression, destabilisation, and plaque rupture. This review focusses on the pharmacology of colchicine, the mechanisms by which it modulates atherosclerosis pathobiology, and summarises the current clinical evidence for its use along with the upcoming clinical trial landscape. Given the current lack of primary immunomodulatory drugs in the treatment of atherosclerosis, colchicine is a promising candidate to fill this therapeutic gap. 2020
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Galougahi, Keyvan Karimi; Chadban, Steven James; Mehran, Roxana; Bangalore, Sripal; Chertow, Glenn Matthew; Ali, Ziad A.Coronary artery disease (CAD) is highly prevalent in chronic kidney disease (CKD). CKD modifies the effects of traditional risk factors on atherosclerosis, with CKD-specific mechanisms, such as inflammation and altered mineral metabolism, playing a dominant pathophysiological role as kidney function declines. Traditional risk models and cardiovascular screening tests perform relatively poorly in the CKD population, and medical treatments including lipid-lowering therapies have reduced efficacy. Clinical presentation of cardiac ischemia in CKD is atypical, whereas invasive therapies are associated with higher rates of complications than in with patients with normal or near normal kidney function. The main focus of the present review is on the invasive approach to management of CAD in late-stage CKD, with an in-depth discussion of the findings of the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA)-CKD trial, and their implications for therapeutic approach and future research in this area. We also briefly discuss the existing evidence in the epidemiology, pathogenesis, diagnosis, and medical management of CAD in late-stage CKD, end-stage kidney disease (ESKD), and kidney transplant recipients. We enumerate the evidence gap left by the frequent exclusion of patients with CKD from randomized controlled trials and highlight the priority areas for future research in the CKD population. 2021 International Society of Nephrology
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Bubb, Kristen J.; Tang, Owen; Gentile, Carmine; Moosavi, Seyed M.; Hansen, Thomas S.; Liu, Chiachi; Di Bartolo, Belinda Ann; Figtree, Gemma A.Nitric oxide (NO) production by eNOS (endothelial NO synthase) is critical for vascular health. Oxidative stress-induced uncoupling of eNOS leads to decreased NO bioavailability, compounded by increased superoxide generation. FXYD1 (FXYD domain containing ion transport regulator 1), a caveolar protein, protects against oxidative inhibition of the Na+-K+-ATPase. We hypothesized that FXYD1 may afford a similar inhibition of oxidative dysregulation of eNOS, providing a broader protection within caveolae. FXYD1-eNOS colocalization was demonstrated by co-immunoprecipitation in heart protein and by proximity ligation assay in human umbilical vein endothelial cells. The functional nature of this partnership was shown by silencing FXYD1 in human umbilical vein endothelial cells, where 50% decreased NO and 2-fold augmented superoxide was shown. Three-dimensional cocultured cardiac spheroids generated from FXYD1 knockout mice were incapable of acetylcholine-induced NO production. Overexpression of FXYD1 in HEK293 cells revealed a possible mechanism, where FXYD1 protected against redox modification of eNOS cysteines. In vivo, vasodilation in response to increasing doses of bradykinin was impaired in knockout mice, and this was rescued in mice by delivery of FXYD1 protein packaged in exosomes. Bloods vessels extracted from knockout mice exhibited increased oxidative and nitrosative stress with evidence of reduce eNOS phosphorylation. Impaired vascular function and augmented superoxide generation were also evident in diabetic knockout mice. Despite this, blood pressure was similar in wildtype and knockout mice, but after chronic angiotensin II infusion, knockout of FXYD1 was associated with a heightened blood pressure response. FXYD1 protects eNOS from dysregulated redox signaling and is protective against both hypertension and diabetic vascular oxidative stress. 2021 Lippincott Williams and Wilkins. All rights reserved.
