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Characterization of sinoatrial automaticity in Microcebus murinus to study the effect of aging on cardiac activity and the correlation with longevity. Sci Rep 2023; 13:3054. [PMID: 36810863 PMCID: PMC9944915 DOI: 10.1038/s41598-023-29723-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
Microcebus murinus, or gray mouse lemur (GML), is one of the smallest primates known, with a size in between mice and rats. The small size, genetic proximity to humans and prolonged senescence, make this lemur an emerging model for neurodegenerative diseases. For the same reasons, it could help understand how aging affects cardiac activity. Here, we provide the first characterization of sinoatrial (SAN) pacemaker activity and of the effect of aging on GML heart rate (HR). According to GML size, its heartbeat and intrinsic pacemaker frequencies lie in between those of mice and rats. To sustain this fast automaticity the GML SAN expresses funny and Ca2+ currents (If, ICa,L and ICa,T) at densities similar to that of small rodents. SAN automaticity was also responsive to β-adrenergic and cholinergic pharmacological stimulation, showing a consequent shift in the localization of the origin of pacemaker activity. We found that aging causes decrease of basal HR and atrial remodeling in GML. We also estimated that, over 12 years of a lifetime, GML generates about 3 billion heartbeats, thus, as many as humans and three times more than rodents of equivalent size. In addition, we estimated that the high number of heartbeats per lifetime is a characteristic that distinguishes primates from rodents or other eutherian mammals, independently from body size. Thus, cardiac endurance could contribute to the exceptional longevity of GML and other primates, suggesting that GML's heart sustains a workload comparable to that of humans in a lifetime. In conclusion, despite the fast HR, GML replicates some of the cardiac deficiencies reported in old people, providing a suitable model to study heart rhythm impairment in aging. Moreover, we estimated that, along with humans and other primates, GML presents a remarkable cardiac longevity, enabling longer life span than other mammals of equivalent size.
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Perera T, Pius C, Niort B, Radcliffe EJ, Dibb KM, Trafford AW, Pinali C. Serial block face scanning electron microscopy reveals region-dependent remodelling of transverse tubules post-myocardial infarction. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210331. [PMID: 36189812 PMCID: PMC9527908 DOI: 10.1098/rstb.2021.0331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The highly organized transverse tubule (t-tubule) network facilitates cardiac excitation-contraction coupling and synchronous cardiac myocyte contraction. In cardiac failure secondary to myocardial infarction (MI), changes in the structure and organization of t-tubules result in impaired cardiac contractility. However, there is still little knowledge on the regional variation of t-tubule remodelling in cardiac failure post-MI. Here, we investigate post-MI t-tubule remodelling in infarct border and remote regions, using serial block face scanning electron microscopy (SBF-SEM) applied to a translationally relevant sheep ischaemia reperfusion MI model and matched controls. We performed minimally invasive coronary angioplasty of the left anterior descending artery, followed by reperfusion after 90 min to establish the MI model. Left ventricular tissues obtained from control and MI hearts eight weeks post-MI were imaged using SBF-SEM. Image analysis generated three-dimensional reconstructions of the t-tubular network in control, MI border and remote regions. Quantitative analysis revealed that the MI border region was characterized by t-tubule depletion and fragmentation, dilation of surviving t-tubules and t-tubule elongation. This study highlights region-dependent remodelling of the tubular network post-MI and may provide novel localized therapeutic targets aimed at preservation or restoration of the t-tubules to manage cardiac contractility post-MI. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Tharushi Perera
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Charlene Pius
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Barbara Niort
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Emma J Radcliffe
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
| | - Christian Pinali
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, 46 Grafton Street, Manchester M13 9NT, UK
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Liu W, Nguyen-Truong M, Ahern M, Labus KM, Puttlitz CM, Wang Z. Different Passive Viscoelastic Properties Between the Left and Right Ventricles in Healthy Adult Ovine. J Biomech Eng 2021; 143:1115540. [PMID: 34350934 DOI: 10.1115/1.4052004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Indexed: 01/03/2023]
Abstract
Ventricle dysfunction is the most common cause of heart failure, which leads to high mortality and morbidity. The mechanical behavior of the ventricle is critical to its physiological function. It is known that the ventricle is anisotropic and viscoelastic. However, the understanding of ventricular viscoelasticity is much less than that of its elasticity. Moreover, the left and right ventricles (LV&RV) are different in embryologic origin, anatomy, and function, but whether they distinguish in viscoelastic properties is unclear. We hypothesized that passive viscoelasticity is different between healthy LVs and RVs. Ex vivo cyclic biaxial tensile mechanical tests (1, 0.1, 0.01 Hz) and stress relaxation (strain of 3, 6, 9, 12, 15%) were performed for ventricles from healthy adult sheep. Outflow track direction was defined as the longitudinal direction. Hysteresis stress-strain loops and stress relaxation curves were obtained to quantify the viscoelastic properties. We found that the RV had more pronounced frequency-dependent viscoelastic changes than the LV. Under the physiological frequency (1 Hz), the LV was more anisotropic in the elasticity and stiffer than the RV in both directions, whereas the RV was more anisotropic in the viscosity and more viscous than the LV in the longitudinal direction. The LV was quasi-linear viscoelastic in the longitudinal but not circumferential direction, and the RV was nonlinear viscoelastic in both directions. This study is the first to investigate passive viscoelastic differences in healthy LVs and RVs, and the findings will deepen the understanding of biomechanical mechanisms of ventricular function.
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Affiliation(s)
- Wenqiang Liu
- School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523
| | - Michael Nguyen-Truong
- School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523
| | - Matt Ahern
- School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523
| | - Kevin M Labus
- Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery,Fort Collins, CO 80523
| | - Christian M Puttlitz
- School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523; Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523; Department of Clinical Sciences, Colorado State University, 1678 Campus Delivery, Fort Collins, CO 80523
| | - Zhijie Wang
- Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523; School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523; 1301 Campus Delivery, Fort Collins, CO 80523
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Fuentes S, Gonzalez Viejo C, Chauhan SS, Joy A, Tongson E, Dunshea FR. Non-Invasive Sheep Biometrics Obtained by Computer Vision Algorithms and Machine Learning Modeling Using Integrated Visible/Infrared Thermal Cameras. SENSORS (BASEL, SWITZERLAND) 2020; 20:E6334. [PMID: 33171995 PMCID: PMC7664231 DOI: 10.3390/s20216334] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 01/05/2023]
Abstract
Live sheep export has become a public concern. This study aimed to test a non-contact biometric system based on artificial intelligence to assess heat stress of sheep to be potentially used as automated animal welfare assessment in farms and while in transport. Skin temperature (°C) from head features were extracted from infrared thermal videos (IRTV) using automated tracking algorithms. Two parameter engineering procedures from RGB videos were performed to assess Heart Rate (HR) in beats per minute (BPM) and respiration rate (RR) in breaths per minute (BrPM): (i) using changes in luminosity of the green (G) channel and (ii) changes in the green to red (a) from the CIELAB color scale. A supervised machine learning (ML) classification model was developed using raw RR parameters as inputs to classify cutoff frequencies for low, medium, and high respiration rate (Model 1). A supervised ML regression model was developed using raw HR and RR parameters from Model 1 (Model 2). Results showed that Models 1 and 2 were highly accurate in the estimation of RR frequency level with 96% overall accuracy (Model 1), and HR and RR with R = 0.94 and slope = 0.76 (Model 2) without statistical signs of overfitting.
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Affiliation(s)
- Sigfredo Fuentes
- Digital Agriculture, Food and Wine Sciences Group, School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; (C.G.V.); (E.T.)
| | - Claudia Gonzalez Viejo
- Digital Agriculture, Food and Wine Sciences Group, School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; (C.G.V.); (E.T.)
| | - Surinder S. Chauhan
- Animal Nutrition and Physiology, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville 3010, Australia; (S.S.C.); (A.J.); (F.R.D.)
| | - Aleena Joy
- Animal Nutrition and Physiology, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville 3010, Australia; (S.S.C.); (A.J.); (F.R.D.)
| | - Eden Tongson
- Digital Agriculture, Food and Wine Sciences Group, School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; (C.G.V.); (E.T.)
| | - Frank R. Dunshea
- Animal Nutrition and Physiology, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville 3010, Australia; (S.S.C.); (A.J.); (F.R.D.)
- Faculty of Biological Sciences, The University of Leeds, Leeds LS2 9JT, UK
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Konold T, Phelan LJ, Donnachie BR, Chaplin MJ, Cawthraw S, González L. Codon 141 polymorphisms of the ovine prion protein gene affect the phenotype of classical scrapie transmitted from goats to sheep. BMC Vet Res 2017; 13:122. [PMID: 28472956 PMCID: PMC5418773 DOI: 10.1186/s12917-017-1036-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 04/21/2017] [Indexed: 11/14/2022] Open
Abstract
Background A study to investigate transmission of classical scrapie via goat milk was carried out in sheep: firstly, lambs were challenged orally with goat scrapie brain homogenate to confirm transmission of scrapie from goats to sheep. In the second study phase, milk from scrapie-infected goats was fed to lambs. Lambs were selected according to their prion protein gene (PRNP) genotype, which was either VRQ/VRQ or ARQ/ARQ, with or without additional polymorphisms at codon 141 (FF141, LF141 or LL141) of the ovine PRNP. This report describes the clinical, pathological and molecular phenotype of goat scrapie in those sheep that progressed to clinical end-stage. Results Ten sheep (six VRQ/VRQ and four ARQ/ARQ, of which three FF141 and one LL141) challenged with one of two scrapie brain homogenates, and six pairs of sheep (ARQ, of which five LL141 and seven LF141) fed milk from six different goats, developed clinical disease, which was characterised by a pruritic (all VRQ/VRQ and LL141 sheep) or a non-pruritic form (all LF141 and FF141 sheep). Immunohistochemical (IHC) examination revealed that the pattern of intra- and extracellular accumulation of disease-associated prion protein in the brain was also dependent on PRNP polymorphisms at codon 141, which was similar in VRQ and LL141 sheep but different from LF141 and FF141 sheep. The influence of codon 141 was also seen in discriminatory Western blot (WB), with LF141 and FF141 sheep showing a bovine spongiform encephalopathy-like profile (diminished reactivity with P4 antibody) on brain tissue. However, discriminatory WB in lymphoid tissues, and IHC pattern and profile both in lymphoid and brain tissue was consistent with classical scrapie in all sheep. Conclusions This study provided further evidence that the clinical presentation and the pathological and molecular phenotypes of scrapie in sheep are influenced by PRNP polymorphisms, particularly at codon 141. Differences in the truncation of disease-associated prion protein between LL141 sheep and those carrying the F141 allele may be responsible for these observations. Electronic supplementary material The online version of this article (doi:10.1186/s12917-017-1036-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Timm Konold
- Animal Sciences Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK.
| | - Laura J Phelan
- Animal Sciences Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK
| | - Ben R Donnachie
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, UK
| | - Melanie J Chaplin
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, UK
| | - Saira Cawthraw
- Central Sequencing Unit, Animal and Plant Health Agency Weybridge, Addlestone, UK
| | - Lorenzo González
- Pathology Department, Animal and Plant Health Agency Lasswade, Penicuik, UK
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