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Yurista SR, Chong CR, Badimon JJ, Kelly DP, de Boer RA, Westenbrink BD. Therapeutic Potential of Ketone Bodies for Patients With Cardiovascular Disease: JACC State-of-the-Art Review. J Am Coll Cardiol 2021; 77:1660-1669. [PMID: 33637354 DOI: 10.1016/j.jacc.2020.12.065] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 12/14/2020] [Indexed: 12/19/2022]
Abstract
Metabolic perturbations underlie a variety of cardiovascular disease states; yet, metabolic interventions to prevent or treat these disorders are sparse. Ketones carry a negative clinical stigma as they are involved in diabetic ketoacidosis. However, evidence from both experimental and clinical research has uncovered a protective role for ketones in cardiovascular disease. Although ketones may provide supplemental fuel for the energy-starved heart, their cardiovascular effects appear to extend far beyond cardiac energetics. Indeed, ketone bodies have been shown to influence a variety of cellular processes including gene transcription, inflammation and oxidative stress, endothelial function, cardiac remodeling, and cardiovascular risk factors. This paper reviews the bioenergetic and pleiotropic effects of ketone bodies that could potentially contribute to its cardiovascular benefits based on evidence from animal and human studies.
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Affiliation(s)
- Salva R Yurista
- University Medical Center Groningen, University of Groningen, Department of Cardiology, Groningen, the Netherlands. https://twitter.com/salvareverentia
| | - Cher-Rin Chong
- Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Australia; Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Juan J Badimon
- AtheroThrombosis Research Unit, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Daniel P Kelly
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rudolf A de Boer
- University Medical Center Groningen, University of Groningen, Department of Cardiology, Groningen, the Netherlands. https://twitter.com/Rudolf_deboer
| | - B Daan Westenbrink
- University Medical Center Groningen, University of Groningen, Department of Cardiology, Groningen, the Netherlands.
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Ong GJ, Nguyen TH, Kucia A, Liu SF, Surikow SY, Girolamo O, Chong CR, Chirkov YY, Schenck-Gustafsson K, Frenneaux MP, Horowitz JD. Takotsubo Syndrome: Finally Emerging From the Shadows? Heart Lung Circ 2020; 30:36-44. [PMID: 33168470 DOI: 10.1016/j.hlc.2020.10.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/20/2022]
Abstract
It is now 30 years since Japanese investigators first described Takotsubo Syndrome (TTS) as a disorder occurring mainly in ageing women, ascribing it to the impact of multivessel coronary artery spasm. During the intervening period, it has become clear that TTS involves relatively transient vascular injury, followed by prolonged myocardial inflammatory and eventually fibrotic changes. Hence symptomatic recovery is generally slow, currently an under-recognised issue. It appears that TTS is induced by aberrant post-β2-adrenoceptor signalling in the setting of "surge" release of catecholamines. Resultant activation of nitric oxide synthases and increased inflammatory vascular permeation lead to prolonged myocardial infiltration with macrophages and associated oedema formation. Initially, the diagnosis of TTS was made via exclusion of relevant coronary artery stenoses, plus the presence of regional left ventricular hypokinesis. However, detection of extensive myocardial oedema on cardiac MRI imaging offers a specific basis for diagnosis. No adequate methods are yet available for definitive diagnosis of TTS at hospital presentation. Other major challenges remaining in this area include understanding of the recently demonstrated association between TTS and antecedent cancer, the development of effective treatments to reduce risk of short-term (generally due to shock) and long-term mortality, and also to accelerate symptomatic recovery.
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Affiliation(s)
- Gao Jing Ong
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia; Central Adelaide Local Health Network, Adelaide, SA, Australia
| | - Thanh Ha Nguyen
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Angela Kucia
- University of South Australia, North Terrace, Adelaide, SA, Australia; Northern Adelaide Local Health Network, Adelaide, SA, Australia
| | - Sai-Fei Liu
- University of Adelaide, North Terrace, Adelaide, SA, Australia; Central Adelaide Local Health Network, Adelaide, SA, Australia; University of South Australia, North Terrace, Adelaide, SA, Australia
| | - Sven Y Surikow
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; Northern Adelaide Local Health Network, Adelaide, SA, Australia
| | - Olivia Girolamo
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Cher-Rin Chong
- Central Adelaide Local Health Network, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Yuliy Y Chirkov
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia
| | | | | | - John D Horowitz
- Basil Hetzel Institute, Queen Elizabeth Hospital, Adelaide, SA, Australia; University of Adelaide, North Terrace, Adelaide, SA, Australia.
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Liu S, Ngo D, Chirkov Y, Stansborough J, Chong CR, Horowitz JD. Prolonged suppression of the anti-oxidant/anti-inflammatory effects of BNP post-Takotsubo syndrome. ESC Heart Fail 2020; 7:2250-2257. [PMID: 32597024 PMCID: PMC7524045 DOI: 10.1002/ehf2.12729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 03/12/2020] [Accepted: 04/03/2020] [Indexed: 01/02/2023] Open
Abstract
AIMS Takotsubo syndrome (TTS) episodes are primarily initiated by 'pulse' release of catecholamines inducing neutrophil infiltration and myocardial inflammation in susceptible individuals (largely ageing women). Evidence of myocardial inflammation and associated energetic impairment persists for ≥ 3 months post-acute TTS episodes, suggesting the existence of additional 'perpetuating' mechanisms. The effects of B-type natriuretic peptide (BNP) in suppressing superoxide (O2 - ) release from neutrophils are transiently impaired in acute heart failure. We also evaluated the extent and duration of BNP-induced suppression of O2 - release post-TTS. METHODS AND RESULTS TTS patients were studied acutely (n = 34) and 3 months thereafter (n = 13) and compared with control subjects (n = 25). O2 - generation from neutrophils, triggered by N-formyl-methionyl-leucyl-phenylalanine and phorbol myristate acetate, and its suppression by BNP, were measured in vitro. Determinants of variability in BNP effect were sought via univariate and multivariate analyses. Relative to control subjects, in TTS patients, BNP suppression of both phorbol myristate acetate and N-formyl-methionyl-leucyl-phenylalanine-induced O2 - release was impaired acutely (P < 0.05 for both); this did not improve over the 3-month recovery period, despite treatment with conventional anti-failure medication in 85% of patients. No significant correlates of BNP effect (other than TTS) were identified. CONCLUSIONS (1) While TTS is associated with marked and prolonged release of BNP, there is virtually total loss of the ability of BNP to suppress neutrophil O2 - release and its impact on tissue inflammation. (2) BNP responses do not recover for at least 3 months post-attacks, suggesting that this might contribute to perpetuation of myocardial inflammation in TTS patients.
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Affiliation(s)
- Saifei Liu
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, 28 Woodville Road, Woodville South, South Australia, 5011, Australia.,Department of Cardiology, The Queen Elizabeth Hospital, South Australia, Australia
| | - Doan Ngo
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, 28 Woodville Road, Woodville South, South Australia, 5011, Australia.,School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, New South Wales, Australia
| | - Yuliy Chirkov
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, 28 Woodville Road, Woodville South, South Australia, 5011, Australia.,Department of Cardiology, The Queen Elizabeth Hospital, South Australia, Australia
| | | | - Cher-Rin Chong
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, 28 Woodville Road, Woodville South, South Australia, 5011, Australia.,Department of Cardiology, The Queen Elizabeth Hospital, South Australia, Australia
| | - John D Horowitz
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, 28 Woodville Road, Woodville South, South Australia, 5011, Australia
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Horowitz JD, Chong CR. Matrix metalloproteinase-2 activation: critical to myocardial contractile dysfunction following ischaemia-reperfusion. Cardiovasc Res 2020; 116:876-878. [PMID: 31800010 DOI: 10.1093/cvr/cvz271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- John D Horowitz
- Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Woodville Road, Woodville, SA 5011, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Cher-Rin Chong
- Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Woodville Road, Woodville, SA 5011, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, Australia
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Kadir AA, Chong C, Clarke K, Evans R. Anaplerosis from asparagine increases ketone oxidation in isolated rat hearts in the absence of pyruvate precursors. J Mol Cell Cardiol 2020. [DOI: 10.1016/j.yjmcc.2019.11.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Drury NE, Yim I, Patel AJ, Oswald NK, Chong CR, Stickley J, Jones TJ. Cardioplegia in paediatric cardiac surgery: a systematic review of randomized controlled trials. Interact Cardiovasc Thorac Surg 2019; 28:144-150. [PMID: 29947787 DOI: 10.1093/icvts/ivy199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 05/24/2018] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Cardioplegia is the primary method for myocardial protection during cardiac surgery. We conducted a systematic review of randomized controlled trials of cardioplegia in children to evaluate the current evidence base. METHODS We searched MEDLINE, CENTRAL and LILACS and manually screened retrieved references and systematic reviews to identify all randomized controlled trials comparing cardioplegia solutions or additives in children undergoing cardiac surgery published in any language; secondary publications and those reporting inseparable adult data were excluded. Two or more reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases. RESULTS We identified 26 trials randomizing 1596 children undergoing surgery; all were single-centre, Phase II trials, recruiting few patients (median 48, interquartile range 30-99). The most frequent comparison was blood versus crystalloid in 10 (38.5%) trials, and the most common end points were biomarkers of myocardial injury (17, 65.4%), inotrope requirements (15, 57.7%) and length of stay in the intensive care unit (11, 42.3%). However, the heterogeneity of patients, interventions and reported outcome measures prohibited meta-analysis. Overall risk of bias was high in 3 (11.5%) trials, unclear in 23 (88.5%) and low in none. CONCLUSIONS The current literature on cardioplegia in children contains no late phase trials. The small size, inconsistent use of end points and low quality of reported trials provide a limited evidence base to inform practice. A core outcome set of clinically important, standardized, validated end points for assessing myocardial protection in children should be developed to facilitate the conduct of high-quality, multicentre trials. PROSPERO registration CRD42017080205.
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Affiliation(s)
- Nigel E Drury
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK.,Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK
| | - Ivan Yim
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK
| | - Akshay J Patel
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK
| | - Nicola K Oswald
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK
| | - Cher-Rin Chong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - John Stickley
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK
| | - Timothy J Jones
- Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, UK
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Drury NE, Patel AJ, Oswald NK, Chong CR, Stickley J, Barron DJ, Jones TJ. Randomized controlled trials in children's heart surgery in the 21st century: a systematic review. Eur J Cardiothorac Surg 2018; 53:724-731. [PMID: 29186478 PMCID: PMC5848812 DOI: 10.1093/ejcts/ezx388] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/27/2017] [Accepted: 10/17/2017] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES Randomized controlled trials are the gold standard for evaluating health care interventions, yet are uncommon in children's heart surgery. We conducted a systematic review of clinical trials in paediatric cardiac surgery to evaluate the scope and quality of the current international literature. METHODS We searched MEDLINE, CENTRAL and LILACS, and manually screened retrieved references and systematic reviews to identify all randomized controlled trials reporting the effect of any intervention on the conduct or outcomes of heart surgery in children published in any language since January 2000; secondary publications and those reporting inseparable adult data were excluded. Two reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases. RESULTS We identified 333 trials from 34 countries randomizing 23 902 children. Most were early phase (313, 94.0%), recruiting few patients (median 45, interquartile range 28-82), and only 11 (3.3%) directly evaluated a surgical intervention. One hundred and nine (32.7%) trials calculated a sample size, 52 (15.6%) reported a CONSORT diagram, 51 (15.3%) were publicly registered and 25 (7.5%) had a Data Monitoring Committee. The overall risk of bias was low in 22 (6.6%), high in 69 (20.7%) and unclear in 242 (72.7%). CONCLUSIONS The recent literature in children's heart surgery contains few late-phase clinical trials. Most trials did not conform to the accepted standards of reporting, and the overall risk of bias was low in few studies. There is a need for high-quality, multicentre clinical trials to provide a robust evidence base for contemporary paediatric cardiac surgical practice.
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Affiliation(s)
- Nigel E Drury
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK
| | - Akshay J Patel
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
| | - Nicola K Oswald
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
| | - Cher-Rin Chong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - John Stickley
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
| | - David J Barron
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
| | - Timothy J Jones
- Department of Paediatric Cardiac Surgery, Birmingham Children’s Hospital, Birmingham, UK
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Ajaero CN, Chong CR, Procter NEK, Liu S, Chirkov YY, Heresztyn T, Chan WPA, Arstall MA, McGavigan AD, Frenneaux MP, Horowitz JD. Does cardiac resynchronization therapy restore peripheral circulatory homeostasis? ESC Heart Fail 2017; 5:129-138. [PMID: 29030923 PMCID: PMC5793973 DOI: 10.1002/ehf2.12211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/24/2017] [Accepted: 08/09/2017] [Indexed: 11/17/2022] Open
Abstract
Aims To evaluate whether peripheral circulatory ‘remodelling’ as measured by changes in vascular compliance and in markers of nitric oxide signalling contributes to patient response to cardiac resynchronization therapy (CRT). Methods and results Effects of CRT were evaluated in 33 patients pre‐procedure and 6 months post‐procedure. Peak oxygen consumption, 6 min walk distance, New York Heart Association class, and quality of life score were evaluated. Augmentation index and its interactions with nitric oxide (NO) were evaluated by applanation tonometry. Platelet NO responsiveness and content of thioredoxin‐interacting protein were assessed. Plasma concentrations of N‐terminal proBNP, asymmetric and symmetric dimethylarginine (SDMA), high sensitivity C‐reactive protein, catecholamines, and matrix metalloproteinases‐2 and ‐9 were assessed. Despite significant improvement in 6 min walk distance (P = 0.005), New York Heart Association class (P < 0.001), quality of life (P = 0.001), and all echocardiographic parameters post‐CRT, there were no significant changes in augmentation index measurements, thioredoxin‐interacting protein content, and platelet NO response. Significant falls in N‐terminal proBNP (P = 0.008) and SDMA (P = 0.013; independent of renal function) occurred. Falls in SDMA predicted reduction in high‐sensitivity C‐reactive protein (P = 0.04) and increases in peak oxygen consumption (P = 0.04). There were no correlations between changes in echocardiographic parameters and those in vascular function. Conclusions These data suggest that the beneficial effects of CRT over 6 months are independent of any change in peripheral NO‐related signalling. However, there is evidence that suppression of inflammation occurs, and its magnitude predicts extent of clinical improvement.
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Affiliation(s)
- Chukwudiebube N Ajaero
- The Queen Elizabeth Hospital, Adelaide, Australia.,The University of Adelaide, Adelaide, Australia.,Flinders Medical Centre, Adelaide, Australia
| | - Cher-Rin Chong
- Cardiac Metabolism Research Group, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,School of Medicine, The University of Adelaide, Adelaide, Australia
| | - Nathan E K Procter
- Bob Champion Research and Education Building, University of East Anglia, Norwich, UK
| | - Saifei Liu
- Basil Hetzel Institute, Adelaide, Australia
| | - Yuliy Y Chirkov
- The University of Adelaide, Adelaide, Australia.,Basil Hetzel Institute, Adelaide, Australia
| | | | - Wai Ping Alicia Chan
- The Queen Elizabeth Hospital, Adelaide, Australia.,The University of Adelaide, Adelaide, Australia.,The Lyell McEwin Hospital, Adelaide, Australia
| | - Margaret A Arstall
- The University of Adelaide, Adelaide, Australia.,Northern Adelaide Local Health Network, Adelaide, Australia
| | - Andrew D McGavigan
- Flinders Medical Centre, Adelaide, Australia.,Flinders University, Adelaide, Australia
| | - Michael P Frenneaux
- Bob Champion Research and Education Building, University of East Anglia, Norwich, UK
| | - John D Horowitz
- The Queen Elizabeth Hospital, Adelaide, Australia.,The University of Adelaide, Adelaide, Australia
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Abstract
Diabetes is a risk factor for heart failure and cardiovascular mortality with specific changes to myocardial metabolism, energetics, structure, and function. The gradual impairment of insulin production and signalling in diabetes is associated with elevated plasma fatty acids and increased myocardial free fatty acid uptake and activation of the transcription factor PPARα. The increased free fatty acid uptake results in accumulation of toxic metabolites, such as ceramide and diacylglycerol, activation of protein kinase C, and elevation of uncoupling protein-3. Insulin signalling and glucose uptake/oxidation become further impaired, and mitochondrial function and ATP production become compromised. Increased oxidative stress also impairs mitochondrial function and disrupts metabolic pathways. The diabetic heart relies on free fatty acids (FFA) as the major substrate for oxidative phosphorylation and is unable to increase glucose oxidation during ischaemia or hypoxia, thereby increasing myocardial injury, especially in ageing female diabetic animals. Pharmacological activation of PPARγ in adipose tissue may lower plasma FFA and improve recovery from myocardial ischaemic injury in diabetes. Not only is the diabetic heart energetically-impaired, it also has early diastolic dysfunction and concentric remodelling. The contractile function of the diabetic myocardium negatively correlates with epicardial adipose tissue, which secretes proinflammatory cytokines, resulting in interstitial fibrosis. Novel pharmacological strategies targeting oxidative stress seem promising in preventing progression of diabetic cardiomyopathy, although clinical evidence is lacking. Metabolic agents that lower plasma FFA or glucose, including PPARγ agonism and SGLT2 inhibition, may therefore be promising options.
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Affiliation(s)
- Cher-Rin Chong
- 1 Department of Physiology, Anatomy and Genetics, University of Oxford
| | - Kieran Clarke
- 1 Department of Physiology, Anatomy and Genetics, University of Oxford
| | - Eylem Levelt
- 2 Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital
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Abstract
INTRODUCTION Angina pectoris, or symptomatic myocardial ischaemia, reflects an impairment of coronary blood flow, and usually a deficiency of available myocardial energetics. Treatment options vary with the precise cause, which may vary with regards to the roles of increased myocardial oxygen demand versus reduced supply. Traditionally, organic nitrates, β-adrenoceptor antagonists, and non-dihydropyridine calcium antagonists were the only commonly used prophylactic anti-anginal agents. However, many patients failed to respond adequately to such therapy, and/or were unsuitable for their use. Areas covered: A number of 'new' agents have been shown to represent ancillary forms of prophylactic anti-anginal therapy and are particularly useful in patients who are relatively unsuitable for either percutaneous or surgical revascularisation. These include modulators of myocardial metabolic efficiency, such as perhexiline, trimetazidine and ranolazine, as well as high dose allopurinol, nicorandil and ivabradine. The advantages and disadvantages of these various agents are summarized. Expert opinion: 'Optimal' medical treatment of angina pectoris now includes use of agents primarily intended to reduce risk of infarction (e.g. statins, aspirin, ACE inhibitors). In patients whose angina persists despite the use of 'standard' anti-anginal therapy, and who are not ideal for invasive revascularization options, a number of emerging drugs offer prospects of symptomatic relief.
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Affiliation(s)
- Cher-Rin Chong
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia.,b Pharmacy Department , Queen Elizabeth Hospital , Woodville South , SA , Australia
| | - Gao J Ong
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia
| | - John D Horowitz
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia
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Horowitz JD, Chong CR, Ngo DT, Sverdlov AL. Effects of acute hyperglycaemia on cardiovascular homeostasis: does a spoonful of sugar make the flow-mediated dilatation go down? J Thorac Dis 2016; 7:E607-11. [PMID: 26793371 DOI: 10.3978/j.issn.2072-1439.2015.12.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- John David Horowitz
- Cardiology and Clinical Pharmacology Units, the Queen Elizabeth Hospital and Basil Hetzel Institute, University of Adelaide, Woodville, SA, Australia
| | - Cher-Rin Chong
- Cardiology and Clinical Pharmacology Units, the Queen Elizabeth Hospital and Basil Hetzel Institute, University of Adelaide, Woodville, SA, Australia
| | - Doan T Ngo
- Cardiology and Clinical Pharmacology Units, the Queen Elizabeth Hospital and Basil Hetzel Institute, University of Adelaide, Woodville, SA, Australia
| | - Aaron Leonid Sverdlov
- Cardiology and Clinical Pharmacology Units, the Queen Elizabeth Hospital and Basil Hetzel Institute, University of Adelaide, Woodville, SA, Australia
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Procter NEK, Ball J, Heresztyn T, Nooney VB, Liu S, Chong CR, Ngo DTM, Isenberg JS, Chirkov YY, Stewart S, Horowitz JD. Subtle renal dysfunction and bleeding risk in atrial fibrillation: symmetric dimethylarginine predicts HAS-BLED score. Am J Cardiovasc Dis 2015; 5:101-109. [PMID: 26309773 PMCID: PMC4539096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 07/01/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND Risk of substantial haemorrhage represents a critically important limitation to effective anti-thrombotic treatment in patients with atrial fibrillation (AF). While it is known that this risk is increased in anticoagulated patients either in the presence of anti-aggregatory drugs or concomitant renal insufficiency, there are currently few data on the potential interactions between endogenous platelet aggregability and bleeding risk. OBJECTIVE We therefore evaluated in a cohort of AF patients: (1), the putative relationship between platelet aggregability and HAS-BLED score; (2), the potential biochemical bases for such a relationship. METHODS Patients were included as part of SAFETY, a randomised controlled trial evaluating outpatient management of AF patients. Platelet response to ADP was evaluated via whole blood impedance aggregometry; clinical and biochemical correlates of platelet aggregation were sought via univariate and multivariate analysis. RESULTS Platelet aggregation correlated inversely (r=-0.220, p<0.05) with HAS-BLED score. Univariate biochemical correlates of decreased platelet aggregation were plasma concentrations of symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). On multivariate analyses, plasma SDMA concentration (β=-0.318, p<0.01), platelet content of thioredoxin-interacting protein (Txnip, β=0.261, p<0.05) and plasma thrombospondin-1 (TSP-1, β=0.249, p<0.05) concentration were predictive of platelet ADP response. Consistent with previous reports, plasma SDMA concentrations were strongly and inversely correlated with estimated glomerular filtration rate (eGFR, r=-0.780, p<0.001). CONCLUSIONS These data therefore suggest that (1), physiologically impaired, like pharmacologically impaired, platelet aggregability may increase bleeding risk in anticoagulated AF patients; (2), the biochemical basis for this may include impaired effects of nitric oxide (via Txnip, TSP-1) but also concomitant renal dysfunction.
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Affiliation(s)
- Nathan EK Procter
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Jocasta Ball
- Centre for The Heart and Mind, Mary MacKillop Institute for Health Research, Australian Catholic UniversityMelbourne, Australia
| | - Tamila Heresztyn
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Vivek B Nooney
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of South AustraliaAustralia
| | - Saifei Liu
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Cher-Rin Chong
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Doan TM Ngo
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Jeffrey S Isenberg
- Heart, Lung, Blood and Vascular Medicine Institute, Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of PittsburghPittsburgh, Pennsylvania, U.S.
| | - Yuliy Y Chirkov
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
| | - Simon Stewart
- National Health and Medical Research Council (NHMRC) Centre of Excellence to Reduce Inequality in Heart Disease, Mary MacKillop Institute for Health Research, Australian Catholic UniversityMelbourne, Australia
- Baker IDI Heart and Diabetes InstituteMelbourne, Australia
| | - John D Horowitz
- Basil Hetzel Institute, The Queen Elizabeth Hospital, University of AdelaideAustralia
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Chong CR, Chan WPA, Nguyen TH, Liu S, Procter NEK, Ngo DT, Sverdlov AL, Chirkov YY, Horowitz JD. Thioredoxin-interacting protein: pathophysiology and emerging pharmacotherapeutics in cardiovascular disease and diabetes. Cardiovasc Drugs Ther 2015; 28:347-60. [PMID: 25088927 DOI: 10.1007/s10557-014-6538-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The thioredoxin system, which consists of thioredoxin (Trx), nicotinamide adenine dinucleotide phosphate (NADPH) and thioredoxin reductase (TrxR), has emerged as a major anti-oxidant involved in the maintenance of cellular physiology and survival. Dysregulation in this system has been associated with metabolic, cardiovascular, and malignant disorders. Thioredoxin-interacting protein (TXNIP), also known as vitamin D-upregulated protein or thioredoxin-binding-protein-2, functions as a physiological inhibitor of Trx, and pathological suppression of Trx by TXNIP has been demonstrated in diabetes and cardiovascular diseases. Furthermore, TXNIP effects are partially Trx-independent; these include direct activation of inflammation and inhibition of glucose uptake. Many of the effects of TXNIP are initiated by its dissociation from intra-nuclear binding with Trx or other SH-containing proteins: these effects include its migration to cytoplasm, modulating stress responses in mitochondria and endoplasmic reticulum, and also potentially activating apoptotic pathways. TXNIP also interacts with the nitric oxide (NO) signaling system, with apparent suppression of NO effect. TXNIP production is modulated by redox stress, glucose levels, hypoxia and several inflammatory activators. In recent studies, it has been shown that therapeutic agents including insulin, metformin, angiotensin converting enzyme inhibitors and calcium channel blockers reduce TXNIP expression, although it is uncertain to what extent TXNIP suppression contributes to their clinical efficacy. This review addresses the role of TXNIP in health and in cardiovascular and metabolic disorders. Finally, the potential advantages (and disadvantages) of pharmacological suppression of TXNIP in cardiovascular disease and diabetes are summarized.
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Affiliation(s)
- Cher-Rin Chong
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
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Singh K, Chong CR, Nguyen TH, Stansborough J, Horowitz JD. Reply: Takotsubo Syndrome is a Systemic, rather than Merely a Cardiac, Disease: Possible Effects on the Systemic and Pulmonary Vasculature. Heart Lung Circ 2015; 24:417-8. [DOI: 10.1016/j.hlc.2014.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 10/24/2014] [Indexed: 10/24/2022]
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Chong CR, Liu S, Licari G, Heresztyn T, Chirkov YY, Ngo DT, Horowitz JD. Reversal of hyperglycemia: effects on nitric oxide signaling. Am J Med 2015; 128:427-30. [PMID: 25460870 DOI: 10.1016/j.amjmed.2014.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 11/05/2014] [Accepted: 11/05/2014] [Indexed: 01/25/2023]
Abstract
BACKGROUND Hyperglycemia in patients with acute coronary syndromes is associated with poor outcomes, and its rapid correction with insulin infusion has been shown to restore platelet responsiveness to nitric oxide and to suppress superoxide (O2(-)) generation. Thioredoxin-interacting protein has emerged recently as a pivotal modulator of hyperglycemia-induced inflammation, O2(-) production, and impairment of nitric oxide signaling, but it is not known whether its expression in platelets can be downregulated rapidly. METHODS In 12 hyperglycemic patients with acute coronary syndrome, we evaluated the putative role of thioredoxin-interacting protein suppression in the platelet nitric oxide response after reversal of hyperglycemia with insulin infusion. RESULTS Insulin infusion for 13.0 ± 0.8 (standard error of the mean) hours decreased blood glucose level from 16.6 ± 1.6 mmol/L to 8.7 ± 1.4 mmol/L (P = .002). This induced (1) sensitization of antiaggregatory response to nitric oxide (from 6.5% ± 7.7% to 39.7% ± 7.0%, P < .0001); (2) improved endothelial progenitor cell function (from a median of 45 to 180 colony-forming units, P < .05); and (3) decreases of whole blood reactive oxygen species content (P < .05). However, there was no significant suppression of platelet thioredoxin-interacting protein expression (mean decrease, 59 arbitrary units; 95% confidence interval, -193 to +74). CONCLUSIONS Correction of hyperglycemia in patients with acute coronary syndrome rapidly reverses oxidative stress, restoring both platelet nitric oxide responsiveness and endothelial progenitor cell function, but this process is largely or entirely independent of thioredoxin-interacting protein.
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Affiliation(s)
- Cher-Rin Chong
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia
| | - Saifei Liu
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia
| | - Giovanni Licari
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia
| | - Tamila Heresztyn
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia
| | - Yuliy Y Chirkov
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia
| | - Doan T Ngo
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia
| | - John D Horowitz
- Cardiology and Clinical Pharmacology Department, Basil Hetzel Institute, the Queen Elizabeth Hospital, Woodville, South Australia, Australia; University of Adelaide, Adelaide, Australia.
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Liu S, Ngo DTM, Chong CR, Amarasekera AT, Procter NEK, Licari G, Dautov RF, Stewart S, Chirkov YY, Horowitz JD. Suppression of neutrophil superoxide generation by BNP is attenuated in acute heart failure: a case for 'BNP resistance'. Eur J Heart Fail 2015; 17:475-83. [PMID: 25684282 DOI: 10.1002/ejhf.242] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 12/18/2014] [Accepted: 01/09/2015] [Indexed: 11/08/2022] Open
Abstract
AIMS The release of the B-type natriuretic peptide (BNP) is increased in heart failure (HF), a condition associated with oxidative stress. BNP is known to exert anti-inflammatory effects including suppression of neutrophil superoxide (O2(-)) release. However, BNP-based restoration of homeostasis in HF is inadequate, and the equivocal clinical benefit of a recombinant BNP, nesiritide, raises the possibility of attenuated response to BNP. We therefore tested the hypothesis that BNP-induced suppression of neutrophil O2(-) generation is impaired in patients with acute HF. METHODS AND RESULTS We have recently characterized suppression of neutrophil O2(-) generation (PMA- or fMLP-stimulated neutrophil burst) by BNP as a measure of its physiological activity. In the present study, BNP response was compared in neutrophils of healthy subjects (n = 29) and HF patients (n = 45). Effects of BNP on fMLP-induced phosphorylation of the NAD(P)H oxidase subunit p47phox were also evaluated. In acute HF patients, the suppressing effect of BNP (1 µmol/L) on O2(-) generation was attenuated relative to that in healthy subjects (P < 0.05 for both PMA and fMLP). Analogously, BNP inhibited p47phox phosphorylation in healthy subjects but not in HF patients (P < 0.05). However, O2(-)-suppressing effects of the cell-permeable cGMP analogue (8-pCPT-cGMP) were preserved in acute HF. Conventional HF treatment for 5 weeks partially restored neutrophil BNP responsiveness (n = 25, P < 0.05), despite no significant decrease in plasma NT-proBNP levels. CONCLUSIONS BNP inhibits neutrophil O2(-) generation by suppressing NAD(P)H oxidase assembly. This effect is impaired in acute HF patients, with partial recovery during treatment.
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Affiliation(s)
- Saifei Liu
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The Queen Elizabeth Hospital, The University of Adelaide, South Australia, Australia
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Drury NE, Licari G, Chong CR, Howell NJ, Frenneaux MP, Horowitz JD, Pagano D, Sallustio BC. Relationship between plasma, atrial and ventricular perhexiline concentrations in humans: insights into factors affecting myocardial uptake. Br J Clin Pharmacol 2015; 77:789-95. [PMID: 24117487 DOI: 10.1111/bcp.12254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/22/2013] [Indexed: 11/28/2022] Open
Abstract
AIM Little is known regarding the steady-state uptake of drugs into the human myocardium. Perhexiline is a prophylactic anti-anginal drug which is increasingly also used in the treatment of heart failure and hypertrophic cardiomyopathy. We explored the relationship between plasma perhexiline concentrations and its uptake into the myocardium. METHODS Blood, right atrium ± left ventricle biopsies were obtained from patients treated with perhexiline for a median of 8.5 days before undergoing coronary surgery in the perhexiline arm of a randomized controlled trial. Perhexiline concentrations in plasma and heart tissue were determined by HPLC. RESULTS Atrial biopsies were obtained from 94 patients and ventricular biopsies from 28 patients. The median plasma perhexiline concentration was within the therapeutic range at 0.24 mg l⁻¹ (IQR 0.12-0.44), the median atrial concentration was 6.02 mg kg⁻¹ (IQR 2.70-9.06) and median ventricular concentration was 10.0 mg kg⁻¹ (IQR 5.76-13.1). Atrial (r² = 0.76) and ventricular (r² = 0.73) perhexiline concentrations were closely and directly correlated with plasma concentrations (both P < 0.001). The median atrial : plasma ratio was 21.5 (IQR 18.1-27.1), ventricular : plasma ratio was 34.9 (IQR 24.5-55.2) and ventricular : atrial ratio was 1.67 (IQR 1.39-2.22). Using multiple regression, the best model for predicting steady-state atrial concentration included plasma perhexiline, heart rate and age (r² = 0.83). Ventricular concentrations were directly correlated with plasma perhexiline concentration and length of therapy (r² = 0.84). CONCLUSIONS This study demonstrates that plasma perhexiline concentrations are predictive of myocardial drug concentrations, a major determinant of drug effect. However, net myocardial perhexiline uptake is significantly modulated by patient age, potentially via alteration of myocardial:extracardiac drug uptake.
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Affiliation(s)
- Nigel E Drury
- Departments of Clinical Pharmacology and Cardiology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville, SA, Australia; The Discipline of Surgery, University of Adelaide, Adelaide, SA, Australia; Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, Birmingham, UK
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Procter N, Chong CR, Sverdlov A, Chan W, Chirkov Y, Horowitz J. Aging of Platelet Nitric Oxide Signaling: Pathogenesis, Clinical Implications, and Therapeutics. Semin Thromb Hemost 2014; 40:660-8. [DOI: 10.1055/s-0034-1389082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Nathan Procter
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Cher-Rin Chong
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Aaron Sverdlov
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Wai Chan
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - Yuliy Chirkov
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
| | - John Horowitz
- Department of Cardiology, Basil Hetzel Institute, Queen Elizabeth Hospital, University of Adelaide, Adelaide, Australia
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Singh K, Neil CJ, Nguyen TH, Stansborough J, Chong CR, Dawson D, Frenneaux MP, Horowitz JD. Dissociation of early shock in takotsubo cardiomyopathy from either right or left ventricular systolic dysfunction. Heart Lung Circ 2014; 23:1141-8. [PMID: 25043578 DOI: 10.1016/j.hlc.2014.06.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 06/09/2014] [Accepted: 06/13/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND Takotsubo cardiomyopathy (TTC) is often associated with hypotension and shock. However, development of hypotension/shock in TTC is not closely related to extent of left ventricular (LV) hypokinesis. We sought to determine whether additional right ventricular (RV) involvement in TTC might contribute to hypotension and shock development and thus to prolonged hospital stay (PHS). METHODS We evaluated 102 consecutive TTC patients with acute transthoracic echocardiography (TTE) to detect RV hypokinesis. Correlates of hypotension, shock and PHS were identified by univariate and multivariate analyses. RESULTS Of the 102 patients evaluated, 33% had RV hypokinesis but only 9% had extensive RV involvement. Within the first 24 hours of admission, severe hypotension (systolic blood pressure (SBP) ≤ 90 mmHg) occurred in 21% of the patients and shock (hypotension + peripheral organ hypo-perfusion) in 16.6% of cases. RV involvement was a univariate but not a multivariate correlate of either hypotension or shock and did not result in PHS. On the other hand, RV involvement predicted more extensive LV hypokinesis and LV systolic dysfunction. CONCLUSIONS In TTC, RV hypokinesis occurs in approximately 33% of cases and correlates with more severe LV wall motion abnormality but not with development of hypotension or shock. These data therefore reinforce previous findings that hypotension/shock in TTC are not purely by impaired cardiac output.
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Affiliation(s)
- Kuljit Singh
- Department of Cardiology, Queen Elizabeth Hospital, Adelaide, Australia.
| | - Christopher J Neil
- Department of Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | - Thanh Ha Nguyen
- Department of Cardiology, Queen Elizabeth Hospital, Adelaide, Australia
| | | | - Cher-Rin Chong
- Department of Cardiology, Queen Elizabeth Hospital, Adelaide, Australia
| | - Dana Dawson
- Department of Medicine, University of Aberdeen, Aberdeen, United Kingdom
| | | | - John D Horowitz
- Department of Cardiology, Queen Elizabeth Hospital, Adelaide, Australia
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Phuong H, Choi B, Raman B, Chong CR, Horowitz JD. PM482 Safety profile of long-term myocardial metabolic agent perhexiline. Glob Heart 2014. [DOI: 10.1016/j.gheart.2014.03.1800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Chong CR, Liu S, Nooney VB, Hurst N, Licari G, Ngo DT, Chirkov Y, Horowitz JD. PM220 Hyperglycaemia, rather than diabetes per se, engenders impaired platelet nitric oxide signaling. Glob Heart 2014. [DOI: 10.1016/j.gheart.2014.03.1601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Chong CR, Drury NE, Licari G, Frennaux M, Horowitz J, Pagano D, Sallustio B. PM076 Determinants of acute uptake of the myocardial metabolic modulator perhexiline into human myocardium. Glob Heart 2014. [DOI: 10.1016/j.gheart.2014.03.1484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Neil CJ, Nguyen TH, Sverdlov AL, Chirkov YY, Chong CR, Stansborough J, Beltrame JF, Kucia AM, Zeitz CJ, Frenneaux MP, Horowitz JD. Can we make sense of takotsubo cardiomyopathy? An update on pathogenesis, diagnosis and natural history. Expert Rev Cardiovasc Ther 2014; 10:215-21. [DOI: 10.1586/erc.11.190] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Chong CR, Neil CJ, Nguyen TH, Singh K, Horowitz JD. Reply: To PMID 23585361. Clin Cardiol 2013; 36:E33. [PMID: 23929811 PMCID: PMC6649504 DOI: 10.1002/clc.22186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/04/2013] [Indexed: 10/14/2023] Open
Affiliation(s)
- Cher-Rin Chong
- Clinical Pharmacology and Cardiology Department, Queen Elizabeth Hospital Discipline of Medicine, University of Adelaide Adelaide, Australia
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Chong CR, Horowitz JD. Letters to the Editor. Clin Cardiol 2013; 36:492-3. [DOI: 10.1002/clc.22161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 11/07/2022] Open
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Chong CR, Neil CJ, Nguyen TH, Stansborough J, Law GW, Singh K, Horowitz JD. Dissociation between severity of takotsubo cardiomyopathy and presentation with shock or hypotension. Clin Cardiol 2013; 36:401-6. [PMID: 23585361 DOI: 10.1002/clc.22129] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 03/17/2013] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Takotsubo cardiomyopathy (TTC) is increasingly well-recognized as a cause of chest-pain syndromes, especially in aging females. The most common complications of TTC occur in the first 24 hours post onset of symptoms and include shock and/or arrhythmias. HYPOTHESIS We tested the hypothesis that the severity of early hypotension in TTC reflects the extent of myocardial involvement and dysfunction. METHODS In 80 consecutive TTC patients, correlates of blood pressure on the day of admission were sought via univariate followed by multivariate analysis. RESULTS Mean systolic blood pressure (SBP) on day 1 was 120 ± 24 (SD) mm Hg. During the first 3 days of admission, 39% of patients had SBP <90 mm Hg, and 9% died and/or required intra-aortic balloon pump insertion. The extent of release of N-terminal pro-brain natriuretic peptide, with its potential correlate of associated vasodilator activity, varied inversely with pulmonary-artery saturation, a measure of cardiac output. However, there was no significant relationship between normetanephrine release and SBP. On multivariate analyses there was no significant relationship between SBP and (1) wall-motion score index (as an index of left-ventricular systolic dysfunction) or (2) T2 enhancement on cardiac magnetic resonance imaging and peak N-terminal pro-brain natriuretic peptide (as indices of myocardial inflammation). CONCLUSIONS Although severe hypotension and shock occur commonly during acute stages of TTC, these complications are multifactorial in origin, probably representing a combination of impaired inotropic state and vasodilatation. Importantly, initial hypotension does not imply severe left ventricular inflammation or systolic dysfunction.
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Affiliation(s)
- Cher-Rin Chong
- Clinical Pharmacology and Cardiology Department, Queen Elizabeth Hospital, Adelaide, Australia
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van Aalten DM, Chong CR, Joshua-Tor L. Crystal structure of carboxypeptidase A complexed with D-cysteine at 1.75 A - inhibitor-induced conformational changes. Biochemistry 2000; 39:10082-9. [PMID: 10955996 DOI: 10.1021/bi000952h] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
D-Cysteine differs from the antiarthritis drug D-penicillamine by only two methyl groups on the beta-carbon yet inhibits carboxypeptidase A (CPD) by a distinct mechanism: D-cysteine binds tightly to the active site zinc, while D-penicillamine catalyzes metal removal. To investigate the structural basis for this difference, we solved the crystal structure of carboxypeptidase A complexed with D-cysteine (D-Cys) at 1.75-A resolution. D-Cys binds the active site zinc with a sulfur ligand and forms additional interactions with surrounding side chains of the enzyme. The structure explains the difference in potency between D-Cys and L-Cys and provides insight into the mechanism of D-penicillamine inhibition. D-Cys binding induces a concerted motion of the side chains around the zinc ion, similar to that found in other carboxypeptidase-inhibitor crystal structures and along a limited path. Analysis of concerted motions of CPD and CPD-inhibitor crystal structures reveals a clustering of these structures into distinct groups. Using the restricted conformational flexibility of a drug target in this type of analysis could greatly enhance efficiency in drug design.
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Affiliation(s)
- D M van Aalten
- W. M. Keck Structural Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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Abstract
Zinc metalloprotease inhibitors are usually designed to inactivate the enzyme by forming a stable ternary complex with the enzyme and active-site zinc. D-Cysteine inhibits carboxypeptidase, ZnCPD, by forming such a complex, with a K(i) of 2.3 microM. In contrast, the antiarthritis drug D-penicillamine, D-PEN, which differs from D-Cys only by the presence of two methyl groups on the beta-carbon, inhibits ZnCPD by promoting the release of the active-site zinc. We have given the name catalytic chelator to such inhibitors. Inhibition is a two-step process characterized by formation of a complex with the enzyme (K(i(initial)) = 1.2 mM) followed by release of the active-site zinc at rates up to 420-fold faster than the spontaneous release. The initial rate of substrate hydrolysis at completion of the second step also depends on D-PEN concentration, reflecting formation of a thermodynamic equilibrium governed by the stability constants of chelator and apocarboxypeptidase for zinc (K(i(final)) = 0.25 mM). The interaction of D-PEN and D-Cys with the active-site metal has been examined by replacing the active-site zinc by a chromophoric cobalt atom. Both inhibitors perturb the d-d transitions of CoCPD in the 500-600 nm region within milliseconds of mixing but only the CoCPD.D-Cys complex displays a strong S --> Co(II) charge-transfer band at 340 nm indicative of a metal-sulfur bond. While the D-Cys complex is stable, the CoCPD.D-PEN complex breaks down to apoenzyme and Co(D-PEN)(2) with a half-life of 0.5 s. D-PEN is the first drug found to inhibit a metalloprotease by increasing the dissociation rate constant of the active-site metal. The ability of D-PEN to catalyze metal removal from carboxypeptidase A and other zinc proteases suggests a possible mechanism of action in arthritis and Wilson's disease and may also underlie complications associated with its clinical use.
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Affiliation(s)
- C R Chong
- Center for Biochemical and Biophysical Sciences and Medicine and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
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Abstract
We measured levels of glucose and glycated hemoglobin in the blood of three of the world's smallest nectarivorous birds, the Anna's (Calypte anna), Costa's (Calypte costae), and ruby-throated hummingbirds (Archilochus colubris). Plasma glucose levels of hummingbirds that were fasted overnight (17 mM) were higher than those in any mammal and are among the highest ever measured in a fasting vertebrate. Glucose levels in hummingbirds just after feeding were extreme, rising as high as 42 mM. The surprisingly high blood glucose concentrations in hummingbirds were accompanied by glycated hemoglobin levels that are the highest ever measured in birds but are lower than those of non-diabetic humans. How hummingbirds tolerate blood glucose levels that cause serious neurological and microvascular pathologies in diabetic humans and animals remains unknown.
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Affiliation(s)
- C A Beuchat
- Department of Physiology, University of Arizona, Tucson 85724, USA.
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