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Ruud M, Frisk M, Melleby AO, Norseng PA, Mohamed BA, Li J, Aronsen JM, Setterberg IE, Jakubiczka J, van Hout I, Coffey S, Shen X, Nygård S, Lunde IG, Tønnessen T, Jones PP, Sjaastad I, Gullestad L, Toischer K, Dahl CP, Christensen G, Louch WE. Regulation of cardiomyocyte t-tubule structure by preload and afterload: Roles in cardiac compensation and decompensation. J Physiol 2024. [PMID: 38686538 DOI: 10.1113/jp284566] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
Mechanical load is a potent regulator of cardiac structure and function. Although high workload during heart failure is associated with disruption of cardiomyocyte t-tubules and Ca2+ homeostasis, it remains unclear whether changes in preload and afterload may promote adaptive t-tubule remodelling. We examined this issue by first investigating isolated effects of stepwise increases in load in cultured rat papillary muscles. Both preload and afterload increases produced a biphasic response, with the highest t-tubule densities observed at moderate loads, whereas excessively low and high loads resulted in low t-tubule levels. To determine the baseline position of the heart on this bell-shaped curve, mice were subjected to mildly elevated preload or afterload (1 week of aortic shunt or banding). Both interventions resulted in compensated cardiac function linked to increased t-tubule density, consistent with ascension up the rising limb of the curve. Similar t-tubule proliferation was observed in human patients with moderately increased preload or afterload (mitral valve regurgitation, aortic stenosis). T-tubule growth was associated with larger Ca2+ transients, linked to upregulation of L-type Ca2+ channels, Na+-Ca2+ exchanger, mechanosensors and regulators of t-tubule structure. By contrast, marked elevation of cardiac load in rodents and patients advanced the heart down the declining limb of the t-tubule-load relationship. This bell-shaped relationship was lost in the absence of electrical stimulation, indicating a key role of systolic stress in controlling t-tubule plasticity. In conclusion, modest augmentation of workload promotes compensatory increases in t-tubule density and Ca2+ cycling, whereas this adaptation is reversed in overloaded hearts during heart failure progression. KEY POINTS: Excised papillary muscle experiments demonstrated a bell-shaped relationship between cardiomyocyte t-tubule density and workload (preload or afterload), which was only present when muscles were electrically stimulated. The in vivo heart at baseline is positioned on the rising phase of this curve because moderate increases in preload (mice with brief aortic shunt surgery, patients with mitral valve regurgitation) resulted in t-tubule growth. Moderate increases in afterload (mice and patients with mild aortic banding/stenosis) similarly increased t-tubule density. T-tubule proliferation was associated with larger Ca2+ transients, with upregulation of the L-type Ca2+ channel, Na+-Ca2+ exchanger, mechanosensors and regulators of t-tubule structure. By contrast, marked elevation of cardiac load in rodents and patients placed the heart on the declining phase of the t-tubule-load relationship, promoting heart failure progression. The dependence of t-tubule structure on preload and afterload thus enables both compensatory and maladaptive remodelling, in rodents and humans.
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Affiliation(s)
- Marianne Ruud
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Arne Olav Melleby
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Per Andreas Norseng
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Belal A Mohamed
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Joanna Jakubiczka
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Isabelle van Hout
- Department of Physiology, School of Biomedical Sciences and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ståle Nygård
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Ida G Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Theis Tønnessen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
- Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Peter P Jones
- Department of Physiology, School of Biomedical Sciences and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Lars Gullestad
- Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Karl Toischer
- Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany
| | - Cristen P Dahl
- Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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Chandrasekera D, Shah R, van Hout I, De Jonge W, Bunton R, Parry D, Davis P, Katare R. Combination of precipitation and size exclusion chromatography as an effective method for exosome like extracellular vesicle isolation from pericardial fluids. Nanotheranostics 2023; 7:345-352. [PMID: 37151803 PMCID: PMC10161387 DOI: 10.7150/ntno.82939] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/24/2023] [Indexed: 05/09/2023] Open
Abstract
Extracellular vesicles (EVs), such as exosomes, are nanovesicles that have received significant attention due to their ability to contain various molecular cargos. EVs found in biological fluids have been demonstrated to have therapeutic potential, including as biomarkers. Despite being extensively studied, a significant downfall in EV research is the lack of standardised protocol for its isolation from human biological fluids, where EVs usually exist at low densities. In this study, we tested two well-established EV isolation protocols, precipitation, and size exclusion chromatography (SEC), to determine their efficiency in isolating EVs from the pericardial fluid. Precipitation alone resulted in high yields of low-purity exosomes as tested by DLS analysis, transmission electron microscopy, immunogold labelling and western blotting for the exosomal surface proteins. While EVs isolated by SEC were pure, the concentration was low. Interestingly, the combination of precipitation followed by SEC resulted in high EV yields with good purity. Our results suggest that the combination method can be adapted to isolate EVs from body fluids which have low densities of EV.
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Affiliation(s)
- Dhananjie Chandrasekera
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Rishi Shah
- 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
| | - Willow De Jonge
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Richard Bunton
- Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Dominic Parry
- Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Philip Davis
- Cardiothoracic Surgery, 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
- ✉ Corresponding author: Rajesh Katare, MD PhD, Department of Physiology, HeartOtago, University of Otago, 270, Great King Street, Dunedin, 9016, New Zealand. Tel: +64-3-479-7292;
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Ghosh N, Fenton S, van Hout I, Jones GT, Coffey S, Williams MJA, Sugunesegran R, Parry D, Davis P, Schwenke DO, Chatterjee A, Katare R. Therapeutic knockdown of miR-320 improves deteriorated cardiac function in a pre-clinical model of non-ischemic diabetic heart disease. Mol Ther Nucleic Acids 2022; 29:330-342. [PMID: 35950211 PMCID: PMC9356207 DOI: 10.1016/j.omtn.2022.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/08/2022] [Indexed: 11/17/2022]
Abstract
Non-ischemic diabetic heart disease (NiDHD) is characterized by diastolic dysfunction and decreased or preserved systolic function, eventually resulting in heart failure. Accelerated apoptotic cell death because of alteration of molecular signaling pathways due to dysregulation in microRNAs (miRNAs) plays a significant role in the development of NiDHD. Here, we aimed to determine the pathological role of cardiomyocyte-enriched pro-apoptotic miR-320 in the development of NiDHD. We identified a marked upregulation of miR-320 that was associated with downregulation of its target protein insulin growth factor-1 (IGF-1) in human right atrial appendage tissue in the late stages of cardiomyopathy in type 2 diabetic db/db mice and high-glucose-cultured human ventricular cardiomyocytes (AC-16 cells). In vitro knockdown of miR-320 in high-glucose-exposed AC-16 cells using locked nucleic acid (LNA) anti-miR-320 markedly reduced high-glucose-induced apoptosis by restoring IGF-1 and Bcl-2. Finally, in vivo knockdown of miR-320 in 24-week-old type 2 diabetic db/db mice reduced cardiomyocyte apoptosis and interstitial fibrosis while restoring vascular density. This resulted in partial recovery of the impaired diastolic and systolic function. Our study provides evidence that miR-320 is a late-responding miRNA that aggravates apoptosis and cardiac dysfunction in the diabetic heart, and that therapeutic knockdown of miR-320 is beneficial in partially restoring the deteriorated cardiac function.
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Affiliation(s)
- Nilanjan Ghosh
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sonya Fenton
- 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
| | - Gregory T Jones
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | | | | | - Dominic Parry
- Department of Cardiothoracic Surgery, University of Otago, Dunedin, New Zealand
| | - Philip Davis
- Department of Cardiothoracic Surgery, University of Otago, Dunedin, New Zealand
| | - Daryl O Schwenke
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Anirudha Chatterjee
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.,Honorary Professor, UPES University, Dehradun, India
| | - Rajesh Katare
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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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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Yee-Goh AS, Yamauchi A, van Hout I, Bellae Papannarao J, Sugunesegran R, Parry D, Davis P, Katare R. Cardiac Progenitor Cells and Adipocyte Stem Cells from Same Patients Exhibit In Vitro Functional Differences. Int J Mol Sci 2022; 23:ijms23105588. [PMID: 35628402 PMCID: PMC9141982 DOI: 10.3390/ijms23105588] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/12/2022] [Accepted: 05/15/2022] [Indexed: 02/05/2023] Open
Abstract
Cardiac progenitor cells (CPCs) and adipocyte stem cells (ASCs) are widely tested for their efficacy in repairing the diseased heart with varying results. However, no study has directly compared the functional efficacy of CPCs and ASCs collected from the same patient. CPCs and ASCs were isolated from the right atrial appendage and epicardial adipose tissue of the same patients, using explant culture. The flow cytometry analysis confirmed that both the cell types express common mesenchymal stem cells markers CD90 and CD105. ASCs, in addition, expressed CD29 and CD73. The wound-healing assay demonstrated that CPCs migrate faster to cover the wound area. Both cell types were resistant to hypoxia-induced cell death when exposed to hypoxia and serum deprivation; however, the ASCs showed increased proliferation. Conditioned medium (CM) collected after culturing serum-deprived CPCs and ASCs showed differential secretion patterns, with ASC CM showing an increased IGF-1 level, while CPC CM showed an increased FGF level. Only CPC CM reduced hypoxia-induced apoptosis in AC-16 human ventricular cardiomyocytes, while vascular network formation by endothelial cells was comparable between CPC and ASC CM. In conclusion, ASCs and CPCs exhibit differential characteristics within the same patient, and in vitro studies showed that CPCs have marginally superior functional efficacy.
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Affiliation(s)
- Anthony Soonseng Yee-Goh
- Department of Physiology, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (A.S.Y.-G.); (A.Y.); (I.v.H.); (J.B.P.)
| | - Atsushi Yamauchi
- Department of Physiology, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (A.S.Y.-G.); (A.Y.); (I.v.H.); (J.B.P.)
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (A.S.Y.-G.); (A.Y.); (I.v.H.); (J.B.P.)
| | - Jayanthi Bellae Papannarao
- Department of Physiology, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (A.S.Y.-G.); (A.Y.); (I.v.H.); (J.B.P.)
| | - Ramanen Sugunesegran
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (R.S.); (D.P.); (P.D.)
| | - Dominic Parry
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (R.S.); (D.P.); (P.D.)
| | - Philip Davis
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (R.S.); (D.P.); (P.D.)
| | - Rajesh Katare
- Department of Physiology, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin 9010, New Zealand; (A.S.Y.-G.); (A.Y.); (I.v.H.); (J.B.P.)
- Correspondence: ; Tel.: +64-3-4797292
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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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7
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Frisk M, Le C, Shen X, Røe ÅT, Hou Y, Manfra O, Silva GJJ, van Hout I, Norden ES, Aronsen JM, Laasmaa M, Espe EKS, Zouein FA, Lambert RR, Dahl CP, Sjaastad I, Lunde IG, Coffey S, Cataliotti A, Gullestad L, Tønnessen T, Jones PP, Altara R, Louch WE. Etiology-Dependent Impairment of Diastolic Cardiomyocyte Calcium Homeostasis in Heart Failure With Preserved Ejection Fraction. J Am Coll Cardiol 2021; 77:405-419. [PMID: 33509397 PMCID: PMC7840890 DOI: 10.1016/j.jacc.2020.11.044] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/26/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Whereas heart failure with reduced ejection fraction (HFrEF) is associated with ventricular dilation and markedly reduced systolic function, heart failure with preserved ejection fraction (HFpEF) patients exhibit concentric hypertrophy and diastolic dysfunction. Impaired cardiomyocyte Ca2+ homeostasis in HFrEF has been linked to disruption of membrane invaginations called t-tubules, but it is unknown if such changes occur in HFpEF. OBJECTIVES This study examined whether distinct cardiomyocyte phenotypes underlie the heart failure entities of HFrEF and HFpEF. METHODS T-tubule structure was investigated in left ventricular biopsies obtained from HFrEF and HFpEF patients, whereas cardiomyocyte Ca2+ homeostasis was studied in rat models of these conditions. RESULTS HFpEF patients exhibited increased t-tubule density in comparison with control subjects. Super-resolution imaging revealed that higher t-tubule density resulted from both tubule dilation and proliferation. In contrast, t-tubule density was reduced in patients with HFrEF. Augmented collagen deposition within t-tubules was observed in HFrEF but not HFpEF hearts. A causative link between mechanical stress and t-tubule disruption was supported by markedly elevated ventricular wall stress in HFrEF patients. In HFrEF rats, t-tubule loss was linked to impaired systolic Ca2+ homeostasis, although diastolic Ca2+ removal was also reduced. In contrast, Ca2+ transient magnitude and release kinetics were largely maintained in HFpEF rats. However, diastolic Ca2+ impairments, including reduced sarco/endoplasmic reticulum Ca2+-ATPase activity, were specifically observed in diabetic HFpEF but not in ischemic or hypertensive models. CONCLUSIONS Although t-tubule disruption and impaired cardiomyocyte Ca2+ release are hallmarks of HFrEF, such changes are not prominent in HFpEF. Impaired diastolic Ca2+ homeostasis occurs in both conditions, but in HFpEF, this mechanism for diastolic dysfunction is etiology-dependent.
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Affiliation(s)
- Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway. https://twitter.com/IEMRLouch
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Åsmund T Røe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Yufeng Hou
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ornella Manfra
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Gustavo J J Silva
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Einar S Norden
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Bjørknes College, Oslo, Norway
| | - J Magnus Aronsen
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Martin Laasmaa
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Emil K S Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Fouad A Zouein
- Department of Pharmacology and Toxicology, American University of Beirut Medical Center, Faculty of Medicine, Riad El-Solh, Beirut, Lebanon
| | - Regis R Lambert
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Christen P Dahl
- Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Department of Cardiology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Ida G Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Alessandro Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Lars Gullestad
- Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Theis Tønnessen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway; Department of Cardiothoracic Surgery, Oslo University Hospital Ullevål, Oslo, Norway
| | - Peter P Jones
- Department of Physiology, HeartOtago, University of Otago, Otago, New Zealand
| | - Raffaele Altara
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway. https://twitter.com/IEMRLouch
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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8
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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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9
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Purvis N, Kumari S, Chandrasekera D, Bellae Papannarao J, Gandhi S, van Hout I, Coffey S, Bunton R, Sugunesegran R, Parry D, Davis P, Williams MJA, Bahn A, Katare R. Diabetes induces dysregulation of microRNAs associated with survival, proliferation and self-renewal in cardiac progenitor cells. Diabetologia 2021; 64:1422-1435. [PMID: 33655378 DOI: 10.1007/s00125-021-05405-7] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS Diabetes mellitus causes a progressive loss of functional efficacy in stem cells, including cardiac progenitor cells (CPCs). The underlying molecular mechanism is still not known. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate genes at the post-transcriptional level. We aimed to determine if diabetes mellitus induces dysregulation of miRNAs in CPCs and to test if in vitro therapeutic modulation of miRNAs would improve the functions of diabetic CPCs. METHODS CPCs were isolated from a mouse model of type 2 diabetes (db/db), non-diabetic mice and human right atrial appendage heart tissue. Total RNA isolated from mouse CPCs was miRNA profiled using Nanostring analysis. Bioinformatic analysis was employed to predict the functional effects of altered miRNAs. MS analysis was applied to determine the targets, which were confirmed by western blot analysis. Finally, to assess the beneficial effects of therapeutic modulation of miRNAs in vitro and in vivo, prosurvival miR-30c-5p was overexpressed in mouse and human diabetic CPCs, and the functional consequences were determined by measuring the level of apoptotic cell death, cardiac function and mitochondrial membrane potential (MMP). RESULTS Among 599 miRNAs analysed in mouse CPCs via Nanostring analysis, 16 miRNAs showed significant dysregulation in the diabetic CPCs. Using bioinformatics tools and quantitative real-time PCR (qPCR) validation, four altered miRNAs (miR-30c-5p, miR-329-3p, miR-376c-3p and miR-495-3p) were identified to play an important role in cell proliferation and survival. Diabetes mellitus significantly downregulated miR-30c-5p, while it upregulated miR-329-3p, miR-376c-3p and miR-495-3p. MS analysis revealed proapoptotic voltage-dependent anion-selective channel 1 (VDAC1) as a direct target for miR-30c-5p, and cell cycle regulator, cyclin-dependent protein kinase 6 (CDK6), as the direct target for miR-329-3p, miR-376c-3p and miR-495-3p. Western blot analyses showed a marked increase in VDAC1 expression, while CDK6 expression was downregulated in diabetic CPCs. Finally, in vitro and in vivo overexpression of miR-30c-5p markedly reduced the apoptotic cell death and preserved MMP in diabetic CPCs via inhibition of VDAC1. CONCLUSIONS/INTERPRETATION Our results demonstrate that diabetes mellitus induces a marked dysregulation of miRNAs associated with stem cell survival, proliferation and differentiation, and that therapeutic overexpression of prosurvival miR-30c-5p reduced diabetes-induced cell death and loss of MMP in CPCs via the newly identified target for miR-30c-5p, VDAC1.
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Affiliation(s)
- Nima Purvis
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sweta Kumari
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Dhananjie Chandrasekera
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Jayanthi Bellae Papannarao
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sophie Gandhi
- 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
| | - Sean Coffey
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Richard Bunton
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Ramanen Sugunesegran
- Department of Cardiothoracic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Dominic Parry
- 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
| | - Andrew Bahn
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
| | - Rajesh Katare
- Department of Physiology-HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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10
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Munro ML, van Hout I, Aitken-Buck HM, Sugunesegran R, Bhagwat K, Davis PJ, Lamberts RR, Coffey S, Soeller C, Jones PP. Human Atrial Fibrillation Is Not Associated With Remodeling of Ryanodine Receptor Clusters. Front Cell Dev Biol 2021; 9:633704. [PMID: 33718369 PMCID: PMC7947344 DOI: 10.3389/fcell.2021.633704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 11/26/2020] [Accepted: 02/08/2021] [Indexed: 12/02/2022] Open
Abstract
The release of Ca2+ by ryanodine receptor (RyR2) channels is critical for cardiac function. However, abnormal RyR2 activity has been linked to the development of arrhythmias, including increased spontaneous Ca2+ release in human atrial fibrillation (AF). Clustering properties of RyR2 have been suggested to alter the activity of the channel, with remodeling of RyR2 clusters identified in pre-clinical models of AF and heart failure. Whether such remodeling occurs in human cardiac disease remains unclear. This study aimed to investigate the nanoscale organization of RyR2 clusters in AF patients – the first known study to examine this potential remodeling in diseased human cardiomyocytes. Right atrial appendage from cardiac surgery patients with paroxysmal or persistent AF, or without AF (non-AF) were examined using super-resolution (dSTORM) imaging. Significant atrial dilation and cardiomyocyte hypertrophy was observed in persistent AF patients compared to non-AF, with these two parameters significantly correlated. Interestingly, the clustering properties of RyR2 were remarkably unaltered in the AF patients. No significant differences were identified in cluster size (mean ∼18 RyR2 channels), density or channel packing within clusters between patient groups. The spatial organization of clusters throughout the cardiomyocyte was also unchanged across the groups. RyR2 clustering properties did not significantly correlate with patient characteristics. In this first study to examine nanoscale RyR2 organization in human cardiac disease, these findings indicate that RyR2 cluster remodeling is not an underlying mechanism contributing to altered channel function and subsequent arrhythmogenesis in human AF.
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Affiliation(s)
- Michelle L Munro
- 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
| | - Hamish M Aitken-Buck
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | | | - Krishna Bhagwat
- Department of Cardiothoracic Surgery, Dunedin Hospital, Dunedin, New Zealand
| | - Philip J Davis
- Department of Cardiothoracic Surgery, Dunedin Hospital, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sean Coffey
- Department of Medicine and HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Christian Soeller
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Peter P Jones
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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11
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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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12
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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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13
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Moharram MA, Aitken-Buck HM, Reijers R, Hout IV, Williams MJ, Jones PP, Whalley GA, Lamberts RR, Coffey S. Correlation between epicardial adipose tissue and body mass index in New Zealand ethnic populations. N Z Med J 2020; 133:22-32. [PMID: 32525859] [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] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
AIM We aimed to investigate the correlation between epicardial adipose tissue (EAT) and body mass index (BMI) in different ethnic groups in New Zealand. METHODS The study included 205 individuals undergoing open heart surgery. Māori and Pacific groups were combined to increase statistical power. EAT was measured using 2D echocardiography. RESULTS There were 164 New Zealand Europeans (NZE) and 41 Māori/Pacific participants. The mean (SD) age of the study group was 67.9 (10.1) years, 69.1 (9.5) for NZE and 63.5 (11.4) for Māori/Pacific. BMI was 29.6 (5.5) kg/m2 for NZE and 31.8 (6.2) for Māori/Pacific. EAT thickness was 6.2 (2.2) mm and 6.0 (1.8) mm for NZE and Māori/Pacific, respectively. Using univariate linear regression, BMI showed moderate correlation with EAT in NZE (R2=0.26, p<0.001); however, there was no significant correlation between BMI and EAT in Māori/Pacific patients (R2=0.05, p=0.17). Using multivariate analysis, BMI remained a significant predictor of EAT thickness in NZE (R2 =0.27, p<0.001). CONCLUSIONS BMI was associated with EAT thickness in NZE patients, but not in Māori/Pacific patients. The same level of BMI can carry different connotations of risk in different ethnic groups, with BMI likely being an inconsistent measure of obesity in in Māori/Pacific patients.
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Affiliation(s)
- Mohammed A Moharram
- Department of Medicine, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin
| | - Hamish M Aitken-Buck
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin
| | - Robin Reijers
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin
| | - Isabelle van Hout
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin
| | - Michael Ja Williams
- Department of Medicine, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin
| | - Peter P Jones
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin
| | - Gillian A Whalley
- Department of Medicine, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin
| | - Regis R Lamberts
- Department of Physiology, HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin
| | - Sean Coffey
- Department of Medicine, HeartOtago, Dunedin School of Medicine, University of Otago, Dunedin
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14
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Bussey CT, Babakr AA, Iremonger RR, van Hout I, Wilkins GT, Lamberts RR, Erickson JR. Carvedilol and metoprolol are both able to preserve myocardial function in type 2 diabetes. Physiol Rep 2020; 8:e14394. [PMID: 32170823 PMCID: PMC7070160 DOI: 10.14814/phy2.14394] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/13/2020] [Accepted: 02/16/2020] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Increasing cohorts of patients present with diabetic cardiomyopathy, and with no targeted options, treatment often rely on generic pharmaceuticals such as β-blockers. β-blocker efficacy is heterogenous, with second generation β-blocker metoprolol selectively inhibiting β1 -AR, while third generation β-blocker carvedilol has α1 -AR inhibition, antioxidant, and anti-apoptotic actions alongside nonselective β-AR inhibition. These additional properties have led to the hypothesis that carvedilol may improve cardiac contractility in the diabetic heart to a greater extent than metoprolol. The present study aimed to compare the efficacy of metoprolol and carvedilol on myocardial function in animal models and cardiac tissue from patients with type 2 diabetes and preserved ejection fraction. METHODS Echocardiographic examination of cardiac function and assessment of myocardial function in isolated trabeculae was carried out in patients with and without diabetes undergoing coronary artery bypass grafting (CABG) who were prescribed metoprolol or carvedilol. Equivalent measures were undertaken in Zucker Diabetic Fatty (ZDF) rats following 4 weeks treatment with metoprolol or carvedilol. RESULTS Patients receiving carvedilol compared to metoprolol had no difference in cardiac function, and no difference was apparent in myocardial function between β-blockers. Both β-blockers similarly improved myocardial function in diabetic ZDF rats treated for 4 weeks, without significantly affecting in vivo cardiac function. CONCLUSIONS Metoprolol and carvedilol were found to have no effect on cardiac function in type 2 diabetes with preserved ejection fraction, and were similarly effective in preventing myocardial dysfunction in ZDF rats.
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Affiliation(s)
- Carol T Bussey
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Aram A Babakr
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Rachael R Iremonger
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Isabelle van Hout
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Gerard T Wilkins
- Department of Medicine-HeartOtago, Dunedin School of Medicine, Dunedin Hospital, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Jeffrey R Erickson
- Department of Physiology-HeartOtago, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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15
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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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