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Paudel P, van Hout I, Bunton RW, Parry DJ, Coffey S, McDonald FJ, Fronius M. Epithelial Sodium Channel δ Subunit Is Expressed in Human Arteries and Has Potential Association With Hypertension. Hypertension 2022; 79:1385-1394. [PMID: 35510563 DOI: 10.1161/hypertensionaha.122.18924] [Citation(s) in RCA: 2] [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] [Indexed: 12/18/2022]
Abstract
BACKGROUND Elevated expression and increased activity of vascular epithelial sodium channel (ENaC) can result in vascular dysfunction in small animal models. However, there is limited or no knowledge on expression and function of ENaC channels in human vasculature. Hence, this study explored the expression and function of ENaC in human arteries and their association with hypertension. METHODS Human internal mammary artery (IMA) and aorta were obtained from cardiovascular patients undergoing coronary artery bypass graft surgery. Expression of the ENaC subunit was analyzed by polymerase chain reaction, Western blot, and immunohistochemistry. ENaC function was observed by patch-clamp electrophysiology in endothelial cells isolated from IMA. Levels of ENaC subunit expression levels were compared between arteries from normotensive, uncontrolled hypertensive, and controlled hypertensive patients. RESULTS For the first time, expression of α, β, γ, and δ was detected at mRNA and protein levels in human IMA and aorta. Single-channel patch-clamp recordings identified both αβγ- and δβγ-like channel conductance in primary endothelial cells isolated and cultured from IMA. Reduced expression of the δ subunit was observed in controlled hypertensive IMA, whereas reduced expression of γ-ENaC was observed in controlled hypertensive aorta. CONCLUSIONS These data suggest that functional ENaC channels are expressed in human arteries and their expression levels are associated with hypertension.
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Affiliation(s)
- Puja Paudel
- Department of Physiology, School of Biomedical Sciences (P.P., I.v.H., F.J.M., M.F.), University of Otago, Dunedin, New Zealand.,HeartOtago (P.P., I.v.H., S.C., M.F.), University of Otago, Dunedin, New Zealand
| | - Isabelle van Hout
- Department of Physiology, School of Biomedical Sciences (P.P., I.v.H., F.J.M., M.F.), University of Otago, Dunedin, New Zealand.,HeartOtago (P.P., I.v.H., S.C., M.F.), University of Otago, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Otago Medical School, Dunedin Hospital, New Zealand (R.W.B., D.J.P.)
| | - Dominic J Parry
- Department of Cardiothoracic Surgery, Otago Medical School, Dunedin Hospital, New Zealand (R.W.B., D.J.P.)
| | - Sean Coffey
- HeartOtago (P.P., I.v.H., S.C., M.F.), University of Otago, Dunedin, New Zealand.,Department of Medicine, Otago Medical School (S.C.), University of Otago, Dunedin, New Zealand
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences (P.P., I.v.H., F.J.M., M.F.), University of Otago, Dunedin, New Zealand
| | - Martin Fronius
- Department of Physiology, School of Biomedical Sciences (P.P., I.v.H., F.J.M., M.F.), University of Otago, Dunedin, New Zealand.,HeartOtago (P.P., I.v.H., S.C., M.F.), University of Otago, Dunedin, New Zealand
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2
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Coffey S, Dixit P, Saw EL, Babakr AA, van Hout I, Galvin IF, Saxena P, Bunton RW, Davis PJ, Lamberts RR, Katare R, Williams MJA. Thiamine increases resident endoglin positive cardiac progenitor cells and atrial contractile force in humans: A randomised controlled trial. Int J Cardiol 2021; 341:70-73. [PMID: 34461161 DOI: 10.1016/j.ijcard.2021.08.039] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/13/2021] [Accepted: 08/24/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND The heart has an intrinsic ability to regenerate, orchestrated by progenitor or stem cells. However, the relative complexity of non-resident cardiac progenitor cell (CPC) therapy makes modulation of resident CPCs a more attractive treatment target. Thiamine analogues improve resident CPC function in pre-clinical models. In this double blinded randomised controlled trial (identifier: ACTRN12614000755639), we examined whether thiamine would improve CPC function in humans. METHODS AND RESULTS High dose oral thiamine (one gram twice daily) or matching placebo was administered 3-5 days prior to coronary artery bypass surgery (CABG). Right atrial appendages were collected at the time of CABG, and CPCs isolated. There was no difference in the primary outcome (proliferation ability of CPCs) between treatment groups. Older age was not associated with decreased proliferation ability. In exploratory analyses, isolated CPCs in the thiamine group showed an increase in the proportion of CD34-/CD105+ (endoglin) cells, but no difference in CD34-/CD90+ or CD34+ cells. Thiamine increased maximum force developed by isolated trabeculae, with no difference in relaxation time or beta-adrenergic responsiveness. CONCLUSION Thiamine does not improve proliferation ability of CPC in patients undergoing CABG, but increases the proportion of CD34-/CD105+ cells. Having not met its primary endpoint, this study provides the impetus to re-examine CPC biology prior to any clinical outcome-based trial examining potential beneficial cardiovascular effects of thiamine.
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Affiliation(s)
- Sean Coffey
- Department of Medicine - HeartOtago, Dunedin School of Medicine, University of Otago, New Zealand; Department of Cardiology, Southern District Health Board, New Zealand.
| | - Parul Dixit
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Eng Leng Saw
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Aram A Babakr
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Isabelle van Hout
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Ivor F Galvin
- Department of Cardiothoracic Surgery, Southern District Health Board, New Zealand
| | - Pankaj Saxena
- Department of Cardiothoracic Surgery, Southern District Health Board, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Southern District Health Board, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Southern District Health Board, New Zealand
| | - Regis R Lamberts
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Rajesh Katare
- Department of Physiology - HeartOtago, School of Biomedical Sciences, University of Otago, New Zealand
| | - Michael J A Williams
- Department of Medicine - HeartOtago, Dunedin School of Medicine, University of Otago, New Zealand; Department of Cardiology, Southern District Health Board, New Zealand
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3
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Aitken-Buck HM, Krause J, van Hout I, Davis PJ, Bunton RW, Parry DJ, Williams MJA, Coffey S, Zeller T, Jones PP, Lamberts RR. Long-chain acylcarnitine 18:1 acutely increases human atrial myocardial contractility and arrhythmia susceptibility. Am J Physiol Heart Circ Physiol 2021; 321:H162-H174. [PMID: 34085842 DOI: 10.1152/ajpheart.00184.2021] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-chain acylcarnitines (LCACs) are known to directly alter cardiac contractility and electrophysiology. However, the acute effect of LCACs on human cardiac function is unknown. We aimed to determine the effect of LCAC 18:1, which has been associated with cardiovascular disease, on the contractility and arrhythmia susceptibility of human atrial myocardium. Additionally, we aimed to assess how LCAC 18:1 alters Ca2+ influx and spontaneous Ca2+ release in vitro. Human right atrial trabeculae (n = 32) stimulated at 1 Hz were treated with LCAC 18:1 at a range of concentrations (1-25 µM) for a 45-min period. Exposure to the LCAC induced a dose-dependent positive inotropic effect on myocardial contractility (maximal 1.5-fold increase vs. control). At the 25 µM dose (n = 8), this was paralleled by an enhanced propensity for spontaneous contractions (50% increase). Furthermore, all LCAC 18:1 effects on myocardial function were reversed following LCAC 18:1 washout. In fluo-4-AM-loaded HEK293 cells, LCAC 18:1 dose dependently increased cytosolic Ca2+ influx relative to vehicle controls and the short-chain acylcarnitine C3. In HEK293 cells expressing ryanodine receptor (RyR2), this increased Ca2+ influx was linked to an increased propensity for RyR2-mediated spontaneous Ca2+ release events. Our study is the first to show that LCAC 18:1 directly and acutely alters human myocardial function and in vitro Ca2+ handling. The metabolite promotes proarrhythmic muscle contractions and increases contractility. The exploratory findings in vitro suggest that LCAC 18:1 increases proarrhythmic RyR2-mediated spontaneous Ca2+ release propensity. The direct effects of metabolites on human myocardial function are essential to understand cardiometabolic dysfunction.NEW & NOTEWORTHY For the first time, the fatty acid metabolite, long-chain acylcarnitine 18:1, is shown to acutely increase the arrhythmia susceptibility and contractility of human atrial myocardium. In vitro, this was linked to an influx of Ca2+ and an enhanced propensity for spontaneous RyR2-mediated Ca2+ release.
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Affiliation(s)
- Hamish M Aitken-Buck
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Julia Krause
- University Heart and Vascular Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Otago Medical School-Dunedin Campus, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Otago Medical School-Dunedin Campus, Dunedin Hospital, Dunedin, New Zealand
| | - Dominic J Parry
- Department of Cardiothoracic Surgery, Otago Medical School-Dunedin Campus, Dunedin Hospital, Dunedin, New Zealand
| | - Michael J A Williams
- Department of Medicine, Heart Otago, Otago Medical School-Dunedin Campus, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine, Heart Otago, Otago Medical School-Dunedin Campus, University of Otago, Dunedin, New Zealand
| | - Tanja Zeller
- University Heart and Vascular Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Peter P Jones
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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4
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Daniels LJ, Annandale M, Koutsifeli P, Li X, Bussey CT, van Hout I, Bunton RW, Davis PJ, Coffey S, Katare R, Lamberts RR, Delbridge LMD, Mellor KM. Elevated myocardial fructose and sorbitol levels are associated with diastolic dysfunction in diabetic patients, and cardiomyocyte lipid inclusions in vitro. Nutr Diabetes 2021; 11:8. [PMID: 33558456 PMCID: PMC7870957 DOI: 10.1038/s41387-021-00150-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 01/05/2021] [Accepted: 01/13/2021] [Indexed: 12/22/2022] Open
Abstract
Diabetes is associated with cardiac metabolic disturbances and increased heart failure risk. Plasma fructose levels are elevated in diabetic patients. A direct role for fructose involvement in diabetic heart pathology has not been investigated. The goals of this study were to clinically evaluate links between myocardial fructose and sorbitol (a polyol pathway fructose precursor) levels with evidence of cardiac dysfunction, and to experimentally assess the cardiomyocyte mechanisms involved in mediating the metabolic effects of elevated fructose. Fructose and sorbitol levels were increased in right atrial appendage tissues of type 2 diabetic patients (2.8- and 1.5-fold increase respectively). Elevated cardiac fructose levels were confirmed in type 2 diabetic rats. Diastolic dysfunction (increased E/e’, echocardiography) was significantly correlated with cardiac sorbitol levels. Elevated myocardial mRNA expression of the fructose-specific transporter, Glut5 (43% increase), and the key fructose-metabolizing enzyme, Fructokinase-A (50% increase) was observed in type 2 diabetic rats (Zucker diabetic fatty rat). In neonatal rat ventricular myocytes, fructose increased glycolytic capacity and cytosolic lipid inclusions (28% increase in lipid droplets/cell). This study provides the first evidence that elevated myocardial fructose and sorbitol are associated with diastolic dysfunction in diabetic patients. Experimental evidence suggests that fructose promotes the formation of cardiomyocyte cytosolic lipid inclusions, and may contribute to lipotoxicity in the diabetic heart.
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Affiliation(s)
- Lorna J Daniels
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Marco Annandale
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Parisa Koutsifeli
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Xun Li
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Carol T Bussey
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Rajesh Katare
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Lea M D Delbridge
- Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Kimberley M Mellor
- Department of Physiology, University of Auckland, Auckland, New Zealand. .,Department of Physiology, University of Melbourne, Melbourne, Australia. .,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
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5
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Aitken-Buck HM, Babakr AA, Fomison-Nurse IC, van Hout I, Davis PJ, Bunton RW, Williams MJA, Coffey S, Jones PP, Lamberts RR. Inotropic and lusitropic, but not arrhythmogenic, effects of adipocytokine resistin on human atrial myocardium. Am J Physiol Endocrinol Metab 2020; 319:E540-E547. [PMID: 32715745 DOI: 10.1152/ajpendo.00202.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The adipocytokine resistin is released from epicardial adipose tissue (EAT). Plasma resistin and EAT deposition are independently associated with atrial fibrillation. The EAT secretome enhances arrhythmia susceptibility and inotropy of human myocardium. Therefore, we aimed to determine the effect of resistin on the function of human myocardium and how resistin contributes to the proarrhythmic effect of EAT. EAT biopsies were obtained from 25 cardiac surgery patients. Resistin levels were measured by ELISA in 24-h EAT culture media (n = 8). The secretome resistin concentrations increased over the culture period to a maximal level of 5.9 ± 1.2 ng/mL. Coculture with β-adrenergic agonists isoproterenol (n = 4) and BRL37344 (n = 13) had no effect on EAT resistin release. Addition of resistin (7, 12, 20 ng/mL) did not significantly increase the spontaneous contraction propensity of human atrial trabeculae (n = 10) when given alone or in combination with isoproterenol. Resistin dose-dependently increased trabecula-developed force (maximal 2.9-fold increase, P < 0.0001), as well as the maximal rates of contraction (2.6-fold increase, P = 0.002) and relaxation (1.8-fold increase, P = 0.007). Additionally, the postrest potentiation capacity of human trabeculae was reduced at all resistin doses, suggesting that the inotropic effect induced by resistin might be due to altered sarcoplasmic reticulum Ca2+ handling. EAT resistin release is not modulated by common arrhythmia triggers. Furthermore, exogenous resistin does not promote arrhythmic behavior in human atrial trabeculae. Resistin does, however, induce an acute dose-dependent positive inotropic and lusitropic effect.
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Affiliation(s)
- Hamish M Aitken-Buck
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Aram A Babakr
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ingrid C Fomison-Nurse
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Isabelle van Hout
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Michael J A Williams
- Department of Medicine and HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Peter P Jones
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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6
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Lal S, Gray A, Kim E, Bunton RW, Davis P, Galvin IF, Williams MJ. Frailty in Elderly Patients Undergoing Cardiac Surgery Increases Hospital Stay and 12-Month Readmission Rate. Heart Lung Circ 2020; 29:1187-1194. [DOI: 10.1016/j.hlc.2019.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/16/2019] [Accepted: 10/13/2019] [Indexed: 01/09/2023]
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7
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Babakr AA, Fomison-Nurse IC, van Hout I, Aitken-Buck HM, Sugunesegran R, Davis PJ, Bunton RW, Williams MJA, Coffey S, Stiles MK, Jones PP, Lamberts RR. Acute interaction between human epicardial adipose tissue and human atrial myocardium induces arrhythmic susceptibility. Am J Physiol Endocrinol Metab 2020; 318:E164-E172. [PMID: 31821041 DOI: 10.1152/ajpendo.00374.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epicardial adipose tissue (EAT) deposition has a strong clinical association with atrial arrhythmias; however, whether a direct functional interaction exists between EAT and the myocardium to induce atrial arrhythmias is unknown. Therefore, we aimed to determine whether human EAT can be an acute trigger for arrhythmias in human atrial myocardium. Human trabeculae were obtained from right atrial appendages of patients who have had cardiac surgery (n = 89). The propensity of spontaneous contractions (SCs) in the trabeculae (proxy for arrhythmias) was determined under physiological conditions and during known triggers of SCs (high Ca2+, β-adrenergic stimulation). To determine whether EAT could trigger SCs, trabeculae were exposed to superfusate of fresh human EAT, and medium of 24 h-cultured human EAT treated with β1/2 (isoproterenol) or β3 (BRL37344) adrenergic agonists. Without exposure to EAT, high Ca2+ and β1/2-adrenergic stimulation acutely triggered SCs in, respectively, 47% and 55% of the trabeculae that previously were not spontaneously active. Acute β3-adrenergic stimulation did not trigger SCs. Exposure of trabeculae to either superfusate of fresh human EAT or untreated medium of 24 h-cultured human EAT did not induce SCs; however, specific β3-adrenergic stimulation of EAT did trigger SCs in the trabeculae, either when applied to fresh (31%) or cultured (50%) EAT. Additionally, fresh EAT increased trabecular contraction and relaxation, whereas media of cultured EAT only increased function when treated with the β3-adrenergic agonist. An acute functional interaction between human EAT and human atrial myocardium exists that increases the propensity for atrial arrhythmias, which depends on β3-adrenergic rather than β1/2-adrenergic stimulation of EAT.
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Affiliation(s)
- Aram A Babakr
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ingrid C Fomison-Nurse
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Hamish M Aitken-Buck
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ramanen Sugunesegran
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Michael J A Williams
- Department of Medicine, HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine, HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Martin K Stiles
- Department of Cardiology, Waikato District Health Board, Hamilton, New Zealand
- Waikato Clinical School, University of Auckland, Hamilton, New Zealand
| | - Peter P Jones
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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8
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Aitken-Buck HM, Moharram M, Babakr AA, Reijers R, Van Hout I, Fomison-Nurse IC, Sugunesegran R, Bhagwat K, Davis PJ, Bunton RW, Williams MJA, Stiles MK, Jones PP, Coffey S, Lamberts RR. Relationship between epicardial adipose tissue thickness and epicardial adipocyte size with increasing body mass index. Adipocyte 2019; 8:412-420. [PMID: 31829077 PMCID: PMC6948959 DOI: 10.1080/21623945.2019.1701387] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Macroscopic deposition of epicardial adipose tissue (EAT) has been strongly associated with numerous indices of obesity and cardiovascular disease risk. In contrast, the morphology of EAT adipocytes has rarely been investigated. We aimed to determine whether obesity-driven adipocyte hypertrophy, which is characteristic of other visceral fat depots, is found within EAT adipocytes. EAT samples were collected from cardiac surgery patients (n = 49), stained with haematoxylin & eosin, and analysed for mean adipocyte size and non-adipocyte area. EAT thickness was measured using echocardiography. A significant positive relationship was found between EAT thickness and body mass index (BMI). When stratified into standardized BMI categories, EAT thickness was 58.7% greater (p = 0.003) in patients from the obese (7.3 ± 1.8 mm) compared to normal (4.6 ± 0.9 mm) category. BMI as a continuous variable significantly correlated with EAT thickness (r = 0.56, p < 0.0001). Conversely, no correlation was observed between adipocyte size and either BMI or EAT thickness. No difference in the non-adipocyte area was found between BMI groups. Our results suggest that the increased macroscopic EAT deposition associated with obesity is not caused by adipocyte hypertrophy. Rather, alternative remodelling via adipocyte proliferation might be responsible for the observed EAT expansion.
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Affiliation(s)
- Hamish M. Aitken-Buck
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Mohammed Moharram
- Department of Medicine, HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Aram A Babakr
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Robin Reijers
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Isabelle Van Hout
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ingrid C. Fomison-Nurse
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ramanen Sugunesegran
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Krishna Bhagwat
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Phillip J Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W. Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Michael J. A. Williams
- Department of Medicine, HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Martin K. Stiles
- Department of Cardiology, Waikato District Health Board, Hamilton, New Zealand
- Waikato Clinical School, University of Auckland, Hamilton, New Zealand
| | - Peter P. Jones
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine, HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Regis R. Lamberts
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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9
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Rawal S, Nagesh PT, Coffey S, Van Hout I, Galvin IF, Bunton RW, Davis P, Williams MJA, Katare R. Early dysregulation of cardiac-specific microRNA-208a is linked to maladaptive cardiac remodelling in diabetic myocardium. Cardiovasc Diabetol 2019; 18:13. [PMID: 30696455 PMCID: PMC6352455 DOI: 10.1186/s12933-019-0814-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 01/14/2019] [Indexed: 02/08/2023] Open
Abstract
Background The diabetic heart undergoes remodelling contributing to an increased incidence of heart failure in individuals with diabetes at a later stage. The molecular regulators that drive this process in the diabetic heart are still unknown. Methods Real-time (RT) PCR analysis was performed to determine the expression of cardiac specific microRNA-208a in right atrial appendage (RAA) and left ventricular (LV) biopsy tissues collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery. To determine the time-dependent changes, cardiac tissue were collected from type 2 diabetic mice at different age groups. A western blotting analysis was conducted to determine the expression of contractile proteins α- and β-myosin heavy chain (MHC) and thyroid hormone receptor-α (TR-α), the negative regulator of β-MHC. To determine the beneficial effects of therapeutic modulation of miR-208a, high glucose treated adult mouse HL-1 cardiomyocytes were transfected with anti-miR-208a. Results RT-PCR analysis showed marked upregulation of miR-208a from early stages of diabetes in type 2 diabetic mouse heart, which was associated with a marked increase in the expression of pro-hypertrophic β-MHC and downregulation of TR-α. Interestingly, upregulation of miR-208a preceded the switch of α-/β-MHC isoforms and the development of diastolic and systolic dysfunction. We also observed significant upregulation of miR-208a and modulation of miR-208a associated proteins in the type 2 human diabetic heart. Therapeutic inhibition of miR-208a activity in high glucose treated HL-1 cardiomyocytes prevented the activation of β-MHC and hence the hypertrophic response. Conclusion Our results provide the first evidence that early modulation of miR-208a in the diabetic heart induces alterations in the downstream signaling pathway leading to cardiac remodelling and that therapeutic inhibition of miR-208a may be beneficial in preventing diabetes-induced adverse remodelling of the heart.
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Affiliation(s)
- Shruti Rawal
- Department of Physiology-HeartOtago, Otago School of Medical Sciences, University of Otago, 270, Great King Street, Dunedin, 9010, New Zealand.,New York University, New York, USA
| | - Prashanth Thevakar Nagesh
- Department of Microbiology & Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.,New York University, New York, USA
| | - Sean Coffey
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Isabelle Van Hout
- Department of Physiology-HeartOtago, Otago School of Medical Sciences, University of Otago, 270, Great King Street, Dunedin, 9010, New Zealand
| | - Ivor F Galvin
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Philip Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Michael J A Williams
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Rajesh Katare
- Department of Physiology-HeartOtago, Otago School of Medical Sciences, University of Otago, 270, Great King Street, Dunedin, 9010, New Zealand.
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10
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Munasinghe PE, Riu F, Dixit P, Edamatsu M, Saxena P, Hamer NSJ, Galvin IF, Bunton RW, Lequeux S, Jones G, Lamberts RR, Emanueli C, Madeddu P, Katare R. Data supporting the activation of autophagy genes in the diabetic heart. Data Brief 2015; 5:269-75. [PMID: 26543890 PMCID: PMC4589802 DOI: 10.1016/j.dib.2015.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/04/2015] [Accepted: 09/04/2015] [Indexed: 11/14/2022] Open
Abstract
This data article contains full list of autophagy related genes that are altered in diabetic heart. This article also shows data from in vitro cultured cardiomyocytes that are exposed the high glucose treatment to simulate hyperglycemic state in vitro. The interpretation of these data and further extensive insights into the regulation of SG biogenesis by AMPK can be found in “Type-2 diabetes increases autophagy in the human heart through promotion of Beclin-1 mediated pathway” (Munasinghe et al., in press) [1].
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Affiliation(s)
| | - Federica Riu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Parul Dixit
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Midori Edamatsu
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Pankaj Saxena
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Nathan S J Hamer
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Ivor F Galvin
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Richard W Bunton
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | | | - Greg Jones
- Department of Surgery, University of Otago, New Zealand
| | - Regis R Lamberts
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Costanza Emanueli
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Paolo Madeddu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Rajesh Katare
- Department of Physiology-HeartOtago, University of Otago, New Zealand
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11
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Munasinghe PE, Riu F, Dixit P, Edamatsu M, Saxena P, Hamer NSJ, Galvin IF, Bunton RW, Lequeux S, Jones G, Lamberts RR, Emanueli C, Madeddu P, Katare R. Type-2 diabetes increases autophagy in the human heart through promotion of Beclin-1 mediated pathway. Int J Cardiol 2015; 202:13-20. [PMID: 26386349 DOI: 10.1016/j.ijcard.2015.08.111] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Diabetes promotes progressive loss of cardiac cells, which are replaced by a fibrotic matrix, resulting in the loss of cardiac function. In the current study we sought to identify if excessive autophagy plays a major role in inducing this progressive loss. METHODS AND RESULTS Immunofluorescence and western blotting analysis of the right atrial appendages collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery showed a marked increase in the level of autophagy in the diabetic heart, as evidenced by increased expression of autophagy marker LC3B-II and its mediator Beclin-1 and decreased expression of p62, which incorporates into autophagosomes to be efficiently degraded. Moreover, a marked activation of pro-apoptotic caspase-3 was observed. Electron microscopy showed increased autophagosomes in the diabetic heart. In vivo measurement of autophagic flux by choloroquine injection resulted in further enhancement of LC3B-II in the diabetic myocardium, confirming increased autophagic activity in the type-2 diabetic heart. Importantly, in-vitro genetic depletion of beclin-1 in high glucose treated adult rat cardiomyocytes markedly inhibited the level of autophagy and subsequent apoptotic cell death. CONCLUSIONS These findings demonstrate the pathological role of autophagy in the type-2 diabetic heart, opening up a potentially novel therapeutic avenue for the treatment of diabetic heart disease.
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MESH Headings
- Animals
- Apoptosis/genetics
- Apoptosis Regulatory Proteins/biosynthesis
- Apoptosis Regulatory Proteins/genetics
- Autophagy/genetics
- Beclin-1
- Blotting, Western
- Cells, Cultured
- Diabetes Mellitus, Experimental
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diabetic Cardiomyopathies/genetics
- Diabetic Cardiomyopathies/metabolism
- Diabetic Cardiomyopathies/pathology
- Female
- Gene Expression Regulation
- Humans
- In Situ Nick-End Labeling
- Male
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Mice
- Mice, Obese
- Microscopy, Electron
- Myocardium/metabolism
- Myocardium/ultrastructure
- RNA/genetics
- RNA, Small Interfering/genetics
- Rats
- Rats, Zucker
- Signal Transduction/genetics
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Affiliation(s)
| | - Federica Riu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Parul Dixit
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Midori Edamatsu
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Pankaj Saxena
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Nathan S J Hamer
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Ivor F Galvin
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Richard W Bunton
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | | | - Greg Jones
- Department of Surgery, University of Otago, New Zealand
| | - Regis R Lamberts
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Costanza Emanueli
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Paolo Madeddu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Rajesh Katare
- Department of Physiology-HeartOtago, University of Otago, New Zealand.
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12
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Bussey CT, Hughes G, Saxena P, Galvin IF, Bunton RW, Noye MK, Coffey S, Williams MJA, Baldi JC, Jones PP, Lamberts RR. Chamber-specific changes in calcium-handling proteins in the type 2 diabetic human heart with preserved ejection fraction. Int J Cardiol 2015; 193:53-5. [PMID: 26005176 DOI: 10.1016/j.ijcard.2015.05.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 05/09/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Carol T Bussey
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Gillian Hughes
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Pankaj Saxena
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Ivor F Galvin
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Marilyn K Noye
- Department of Medicine - HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine - HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand; NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, United Kingdom
| | - Michael J A Williams
- Department of Medicine - HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - J Chris Baldi
- Department of Medicine - HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Peter P Jones
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
| | - Regis R Lamberts
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
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13
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Lamberts RR, Lingam SJ, Wang HY, Bollen IAE, Hughes G, Galvin IF, Bunton RW, Bahn A, Katare R, Baldi JC, Williams MJA, Saxena P, Coffey S, Jones PP. Impaired relaxation despite upregulated calcium-handling protein atrial myocardium from type 2 diabetic patients with preserved ejection fraction. Cardiovasc Diabetol 2014; 13:72. [PMID: 24708792 PMCID: PMC3997226 DOI: 10.1186/1475-2840-13-72] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/26/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Diastolic dysfunction is a key factor in the development and pathology of cardiac dysfunction in diabetes, however the exact underlying mechanism remains unknown, especially in humans. We aimed to measure contraction, relaxation, expression of calcium-handling proteins and fibrosis in myocardium of diabetic patients with preserved systolic function. METHODS Right atrial appendages from patients with type 2 diabetes mellitus (DM, n = 20) and non-diabetic patients (non-DM, n = 36), all with preserved ejection fraction and undergoing coronary artery bypass grafting (CABG), were collected. From appendages, small cardiac muscles, trabeculae, were isolated to measure basal and β-adrenergic stimulated myocardial function. Expression levels of calcium-handling proteins, sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) and phospholamban (PLB), and of β1-adrenoreceptors were determined in tissue samples by Western blot. Collagen deposition was determined by picro-sirius red staining. RESULTS In trabeculae from diabetic samples, contractile function was preserved, but relaxation was prolonged (Tau: 74 ± 13 ms vs. 93 ± 16 ms, non-DM vs. DM, p = 0.03). The expression of SERCA2a was increased in diabetic myocardial tissue (0.75 ± 0.09 vs. 1.23 ± 0.15, non-DM vs. DM, p = 0.007), whereas its endogenous inhibitor PLB was reduced (2.21 ± 0.45 vs. 0.42 ± 0.11, non-DM vs. DM, p = 0.01). Collagen deposition was increased in diabetic samples. Moreover, trabeculae from diabetic patients were unresponsive to β-adrenergic stimulation, despite no change in β1-adrenoreceptor expression levels. CONCLUSIONS Human type 2 diabetic atrial myocardium showed increased fibrosis without systolic dysfunction but with impaired relaxation, especially during β-adrenergic challenge. Interestingly, changes in calcium-handling protein expression suggests accelerated active calcium re-uptake, thus improved relaxation, indicating a compensatory calcium-handling mechanism in diabetes in an attempt to maintain diastolic function at rest despite impaired relaxation in the diabetic fibrotic atrial myocardium. Our study addresses important aspects of the underlying mechanisms of diabetes-associated diastolic dysfunction, which is crucial to developing new therapeutic treatments.
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Affiliation(s)
- Regis R Lamberts
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Shivanjali J Lingam
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Heng-Yu Wang
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Ilse AE Bollen
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Gillian Hughes
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Ivor F Galvin
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Richard W Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Andrew Bahn
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Rajesh Katare
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - J Chris Baldi
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Michael JA Williams
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Pankaj Saxena
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine – HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Peter P Jones
- Department of Physiology - HeartOtago, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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14
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Moore A, Shindikar A, Fomison-Nurse I, Riu F, Munasinghe PE, Ram TP, Saxena P, Coffey S, Bunton RW, Galvin IF, Williams MJA, Emanueli C, Madeddu P, Katare R. Rapid onset of cardiomyopathy in STZ-induced female diabetic mice involves the downregulation of pro-survival Pim-1. Cardiovasc Diabetol 2014; 13:68. [PMID: 24685144 PMCID: PMC4073808 DOI: 10.1186/1475-2840-13-68] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/21/2014] [Indexed: 02/06/2023] Open
Abstract
Background Diabetic women are five times more likely to develop congestive heart failure compared with two fold for men. The underlying mechanism for this gender difference is not known. Here we investigate the molecular mechanisms responsible for this female disadvantage and attempt safeguarding cardiomyocytes viability and function through restoration of pro-survival Pim-1. Methods and Results Diabetes was induced by injection of streptozotocin in CD1 mice of both genders. Functional and dimensional parameters measurement using echocardiography revealed diastolic dysfunction in female diabetic mice within 8 weeks after STZ-induced diabetes. This was associated with significant downregulation of pro-survival Pim-1 and upregulation of pro-apoptotic Caspase-3, microRNA-1 and microRNA-208a. Male diabetic mice did not show any significant changes at this time point (P < 0.05 vs. female diabetic). Further, the onset of ventricular remodelling was quicker in female diabetic mice showing marked left ventricular dilation, reduced ejection fraction and poor contractility (P < 0.05 vs. male diabetic at 12 and 16 weeks of STZ-induced diabetes). Molecular analysis of samples from human diabetic hearts confirmed the results of pre-clinical studies, showing marked downregulation of Pim-1 in the female diabetic heart (P < 0.05 vs. male diabetic). Finally, in vitro restoration of Pim-1 reversed the female disadvantage in diabetic cardiomyocytes. Conclusions We provide novel insights into the molecular mechanisms behind the rapid onset of cardiomyopathy in female diabetics. These results suggest the requirement for the development of gender-specific treatments for diabetic cardiomyopathy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Rajesh Katare
- Department of Physiology-HeartOtago, Otago School of Medical Sciences, University of Otago, PO Box 913, Dunedin 9054, New Zealand.
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15
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Ahmadi O, Saxena P, Wilson BKJ, Bunton RW. First rib fracture and Horner's syndrome: a rare clinical entity. Ann Thorac Surg 2012; 95:355. [PMID: 23272863 DOI: 10.1016/j.athoracsur.2012.03.114] [Citation(s) in RCA: 6] [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] [Received: 09/24/2011] [Revised: 03/03/2012] [Accepted: 03/23/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Omid Ahmadi
- Department of Cardiothoracic Surgery, Dunedin Hospital, Dunedin, New Zealand
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16
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Abstract
A combination of cardiac surgery and thyroidectomy as a single stage operation has rarely been reported in the literature. We report on the management of a 64-year-old female undergoing a combined aortic valve replacement and excision of a primary (ectopic) intrathoracic goiter. The literature on combined cardiac surgery and thyroidectomy is also reviewed.
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Affiliation(s)
- Annika Sjoeholm
- Department of Cardiothoracic Surgery, Dunedin Hospital, Dunedin, New Zealand
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17
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Galvin SD, Celi LA, Thomas KN, Clendon TR, Galvin IF, Bunton RW, Ainslie PN. Effects of age and coronary artery disease on cerebrovascular reactivity to carbon dioxide in humans. Anaesth Intensive Care 2010; 38:710-7. [PMID: 20715736 DOI: 10.1177/0310057x1003800415] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alterations in cerebrovascular reactivity to CO2, an index of cerebrovascular function, have been associated with increased risk of stroke. We hypothesised that cerebrovascular reactivity is impaired with increasing age and in patients with symptomatic coronary artery disease (CAD). Cerebrovascular and cardiovascular reactivity to CO2 was assessed at rest and during hypercapnia (5% CO2) and hypocapnia (hyperventilation) in subjects with symptomatic CAD (n=13) and age-matched old (n=9) and young (n=20) controls without CAD. Independent of CAD, reductions in middle cerebral artery blood velocity (transcranial Doppler) and cerebral oxygenation (near-infrared spectroscopy) were correlated with increasing age (r = -0.68, r = -0.51, respectively, P < 0.01). In CAD patients, at rest and during hypercapnia, cerebral oxygenation was lower (P < 0.05 vs. young). Although middle cerebral artery blood velocity reactivity was unaltered in the hypercapnic range, middle cerebral artery blood velocity reactivity to hypocapnia was elevated in the CAD and age-matched controls (P < 0.01 vs. young), and was associated with age (r = 0.62, P < 0.01). Transient drops in arterial PCO2 occur in a range of physiological and pathophysiological situations, therefore, the elevated middle cerebral artery blood velocity reactivity to hypocapnia combined with reductions in middle cerebral artery blood velocity may be important mechanisms underlying neurological risk with aging. In CAD patients, additional reductions in cerebral oxygenation may place them at additional risk of cerebral ischaemia.
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Affiliation(s)
- S D Galvin
- Department of Cardiothoracic Surgery, Section of Surgery, University of Otago and Dunedin Hospital, New Zealand
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18
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Galvin SD, Wademan B, Chu J, Bunton RW. Benign Metastasizing Leiomyoma: A Rare Metastatic Lesion in the Right Ventricle. Ann Thorac Surg 2010; 89:279-81. [DOI: 10.1016/j.athoracsur.2009.06.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 05/22/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
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19
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Parry DJ, Winburn IC, Wilkins GT, Bunton RW. Expanding Retrograde Saphenous Vein Graft Aneurysm Treated With Endovascular Coiling. Ann Thorac Surg 2005; 80:2374-6. [PMID: 16305919 DOI: 10.1016/j.athoracsur.2004.07.083] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Revised: 07/06/2004] [Accepted: 07/14/2004] [Indexed: 10/25/2022]
Abstract
Saphenous vein graft aneurysm is a potentially fatal complication of coronary artery bypass grafting and usually requires surgery. This report describes endovascular coiling of a saphenous vein graft aneurysm that developed after redo coronary artery bypass grafting. The aneurysm occurred in a proximally occluded saphenous vein graft after revascularization of the same target vessel. The procedure required a retrograde approach through a patent left internal mammary and left anterior descending artery to reach and successfully thrombose the aneurysm.
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20
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Abstract
Two cases of primary pulmonary sarcoma which were initially diagnosed as pulmonary thromboembolism are presented. The clinical and radiologic features of pulmonary sarcoma are reviewed, with special emphasis on the features which distinguish it from thromboembolism.
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21
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Couper GS, Bunton RW, Birjiniuk V, DiSesa VJ, Fallon MP, Collins JJ, Cohn LH. Relative risks of left ventricular aneurysmectomy in patients with akinetic scars versus true dyskinetic aneurysms. Circulation 1990; 82:IV248-56. [PMID: 2225412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
From 1971 to 1988, 303 patients underwent left ventricular aneurysm resection. We analyzed preoperative and procedure-related variables to ascertain risk factors for surgery. A distinction was made between akinetic and dyskinetic aneurysms to assess potential relation with postoperative outcome. Indications for surgery were arrhythmia in 20 patients, congestive heart failure in 81, angina in 133, congestive heart failure and angina in 42, and other combinations in the remaining 27 patients. The left ventricular aneurysm was dyskinetic in 180 patients and akinetic in 121. Risk factors and surgical procedures were similar in both groups. Left ventricular ejection fraction was less than or equal to 30% in 98 patients. Coronary bypass grafting was performed in 269 patients, with an average of 2.3 grafts per patient. Mitral valve replacement, the most common concomitant procedure, was performed in 16 patients. Intra-aortic balloon assist was required postoperatively in 47 patients. Overall operative mortality was 13% (38 patients) and was due to low cardiac output in 23 patients and arrhythmia in 12 patients. Univariate and multivariate analyses related early mortality to New York Heart Association functional classification of heart failure, the predominant indications of arrhythmia or congestive heart failure, left ventricular ejection fraction less than or equal to 30%, the need for intra-aortic balloon support, and the excision of an akinetic (18%) rather than dyskinetic (8%) left ventricular aneurysm. Over a follow-up period averaging nearly 5 years, the actuarial survival at 5 years was 63% in the dyskinetic group and 51% in the akinetic group.(ABSTRACT TRUNCATED AT 250 WORDS)
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22
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Bunton RW, Xabregas AA, Miller AP. Pericardial closure after cardiac operations. An animal study to assess currently available materials with particular reference to their suitability for use after coronary artery bypass grafting. J Thorac Cardiovasc Surg 1990; 100:99-107. [PMID: 2195238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An experimental study to assess the performance of currently available pericardial substitutes is described with particular reference to their use after coronary artery bypass grafting. Seventy-two ewes, (six groups of 12 animals) had a 7 x 5 cm portion of the pericardium excised. Each group had either the defect left open, primarily resutured, replaced with coarse Dexon No. 2 mesh (American Cyanamid Co., Danbury, Conn.), replaced with fine Dexon No. 8 mesh, replaced with glutaraldehyde-preserved bovine pericardium, or replaced with polytetrafluoroethylene 0.1 mm surgical membrane. Six animals from each group were assessed at 3 months and the remaining six animals were assessed at 6 months. The open-defect and resutured groups served as control animals. None of the substitutes proved superior to the open-defect group in the prevention of chest wall/lung-to-pericardium adhesions at either 3 or 6 months. The limitations of the animal model in assessing this aspect of substitute performance are discussed. Whereas the bovine pericardium, polytetrafluorethylene, and Dexon No. 8 mesh groups were superior to the resutured group in the prevention of pericardium-to-epithelium adhesions in the area of the patch, this advantage was lost at 6 months when resuturing proved as effective as polytetrafluoroethylene and bovine pericardium. In all groups there was little tendency to produce generalized pericardial adhesions. At 3 months Dexon No. 8 mesh and bovine pericardium produced the least amount of significant epicardial reaction. In two animals in the 3-month polytetrafluoroethylene group and in one animal in the 6-month polytetrafluoroethylene group, a "fibrous peel" was encountered on the inner surface of the patch, which had also become adherent to the epicardium and had obscured the underlying anatomy. At 6 months the open-defect, resutured, and bovine pericardium groups had produced no significant epicardial reaction. In one animal at 6 months the bovine pericardium had become markedly thickened and degenerative. We do not recommend routine closure of the pericardium after coronary artery operations with any of the substitutes investigated in our study.
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Affiliation(s)
- R W Bunton
- Department of Cardiothoracic Surgery, University of Otago, Dunedin, New Zealand
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Monro JL, Bunton RW, Sutherland GR, Keeton BR. Correction of interrupted aortic arch. J Thorac Cardiovasc Surg 1989; 98:421-7. [PMID: 2770323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Twelve consecutive infants with interrupted aortic arch, ventricular septal defect, and persistent ductus arteriosus have had the anomaly repaired without the use of synthetic grafts. In two infants (5 and 9 months) the ductus arteriosus was used for the arch repair. In three patients (mean age 14 days) the left carotid artery was turned down to form the new arch. In the remaining seven (mean age 12 days) a direct anastomosis was achieved, but one of these patients died at operation. Two others in this group also had persistent truncus arteriosus. Five patients have required another operation (two for stenosis of the anastomosis with one death). The 10 survivors (mean follow-up 5 years) are well and support our belief that complete repair without the use of synthetic grafts is the treatment of choice in this rare and difficult group.
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MESH Headings
- Anastomosis, Surgical/methods
- Aorta, Thoracic/abnormalities
- Aorta, Thoracic/diagnostic imaging
- Aorta, Thoracic/surgery
- Ductus Arteriosus, Patent/complications
- Ductus Arteriosus, Patent/diagnostic imaging
- Ductus Arteriosus, Patent/surgery
- Female
- Heart Septal Defects, Ventricular/complications
- Heart Septal Defects, Ventricular/diagnostic imaging
- Heart Septal Defects, Ventricular/surgery
- Humans
- Infant
- Infant, Newborn
- Male
- Prostaglandins/therapeutic use
- Radiography
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Affiliation(s)
- J L Monro
- Department of Cardiac Surgery, General Hospital, Southampton, England
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Affiliation(s)
- N Hollis
- Department of Anaesthesia and Intensive Care, Dunedin Public Hospital, New Zealand
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Bunton RW. Value of serum magnesium estimation in diagnosing myocardial infarction and predicting dysrhythmias after coronary artery bypass grafting. Thorax 1983; 38:946-50. [PMID: 6607548 PMCID: PMC459703 DOI: 10.1136/thx.38.12.946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Serial serum magnesium estimations, beginning before operation, were performed on 200 patients who underwent coronary artery bypass grafting. The results indicate that serum magnesium concentration is of no value in the diagnosis of myocardial infarction in the postoperative patient or in predicting which patients are susceptible to postoperative dysrhythmias. There was no statistically significant difference in serum magnesium values between those patients who had an uncomplicated course and patients who had sustained either myocardial infarction or postoperative dysrhythmia or both.
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Bunton RW. Reintroduction of anti-inflammatory drug therapy after drug-associated gastrointestinal disturbances. N Z Med J 1983; 96:144. [PMID: 6572312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Borrie J, Bunton RW. Jejunal bypass of the cardia for benign stricture: report of six cases. Thorax 1983; 38:31-5. [PMID: 6845259 PMCID: PMC459480 DOI: 10.1136/thx.38.1.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Jejunal bypass has restored normal swallowing in six patients with benign intractable lower oesophageal stricutre resulting from (1) full-thickness reflux oesophagitis and hiatal hernia, (2) reflux associated with columnar-cell-lined oesophagus, (3) ingestion of lye, and (4) achalasia with retort-shaped oesophagus. In this technique a segment of jejunum is joined to oesophagus and stomach without resection of the stricture. The procedure is of greatest value in elderly patients with persistent dysphagia and poor respiratory reserve and when previous surgical procedures have failed to relieve the obstruction caused by a benign stricture. Though the number of such patients is small their needs are great and this procedure has provided excellent relief of symptoms during a follow-up period ranging from three to nine years.
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Bunton RW, Feint JA, Molloy PJ. Heterograft valve replacement experience. Aust N Z J Surg 1982; 52:550-3. [PMID: 6984648 DOI: 10.1111/j.1445-2197.1982.tb06108.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Survey of implantation of porcine heterograft valves in the Dunedin Cardiac Surgical Unit has been reviewed covering 140 patients and 166 valves with a follow-up ranging from 1-55 months. The low mortality, minimal complication rate and absence of long term anticoagulants in the post operative regime are emphasized. Discussion centres on the low rate of complications and the usefulness of this valve. As with all biological valves durability is still in question.
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Bunton RW, Barrett DC, Palmer DG. Reintroduction of anti-inflammatory drug therapy after drug-associated gastro-intestinal disturbances. N Z Med J 1982; 95:582-4. [PMID: 6982441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The relative risks associated with anti-inflammatory drug prescription for patients with an earlier history of drug-associated gastro-intestinal disturbance have been investigated in a retrospective study. Under these circumstances ibuprofen was well tolerated. The risks associated with modified salicylates (principally aspirin in enteric-coated form) and indomethacin suppositories also appeared to be relatively slight. Retreatment with phenylbutazone, oral indomethacin, naproxen and combination therapy was hazardous.
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Abstract
Localized pleural fibromas are a definite clinical entity. Their origin is much debated. Though most arise from the mesothelial cell, occasionally some arise from the pleural fibroblast. The former retain the potential to become malignant. Distinguishing between the two origins can aid prognosis after treatment. The characteristic cell is a spindle-shaped fibroblast. Slits or clefts lined by flattened cells are often present in the tumor. Clinically, pleural fibromas are usually asymptomatic, space-occupying lesions. Chest symptoms are nonspecific. Extrathoracic symptoms, especially arthritis, are not uncommon and occur only in the benign variety. Excision is the treatment of choice, but long-term follow-up is essential, for recurrence is not unknown and is often heralded by the region of arthritic symptoms. Recurrences may be benign or malignant, the latter having a poor prognosis, with most patients dying within 2 years. Experience with benign pleural fibromas seen in 6 patients over a 25-year period is presented.
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Abstract
Two patients with lateral subluxation of the atlas resulting from rheumatoid disease involving the upper cervical spine have been described. The deformity can be suspected on clinical grounds and in one of our two patients spinal cord damage was a sequel. Erosion of the opposing surfaces of the odontoid and lateral masses of the atlas with detachment of the transverse ligament and deeper fibres of the posterior longitudinal ligament appear to underlie this deformity. Radiological confirmation may require AP views with the head tilted to one or other side.
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