1
|
Demirel O, Berezin AE, Mirna M, Boxhammer E, Gharibeh SX, Hoppe UC, Lichtenauer M. Biomarkers of Atrial Fibrillation Recurrence in Patients with Paroxysmal or Persistent Atrial Fibrillation Following External Direct Current Electrical Cardioversion. Biomedicines 2023; 11:1452. [PMID: 37239123 PMCID: PMC10216298 DOI: 10.3390/biomedicines11051452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Atrial fibrillation (AF) is associated with atrial remodeling, cardiac dysfunction, and poor clinical outcomes. External direct current electrical cardioversion is a well-developed urgent treatment strategy for patients presenting with recent-onset AF. However, there is a lack of accurate predictive serum biomarkers to identify the risks of AF relapse after electrical cardioversion. We reviewed the currently available data and interpreted the findings of several studies revealing biomarkers for crucial elements in the pathogenesis of AF and affecting cardiac remodeling, fibrosis, inflammation, endothelial dysfunction, oxidative stress, adipose tissue dysfunction, myopathy, and mitochondrial dysfunction. Although there is ample strong evidence that elevated levels of numerous biomarkers (such as natriuretic peptides, C-reactive protein, galectin-3, soluble suppressor tumorigenicity-2, fibroblast growth factor-23, turn-over collagen biomarkers, growth differential factor-15) are associated with AF occurrence, the data obtained in clinical studies seem to be controversial in terms of their predictive ability for post-cardioversion outcomes. Novel circulating biomarkers are needed to elucidate the modality of this approach compared with conventional predictive tools. Conclusions: Biomarker-based strategies for predicting events after AF treatment require extensive investigation in the future, especially in the presence of different gender and variable comorbidity profiles. Perhaps, a multiple biomarker approach exerts more utilization for patients with different forms of AF than single biomarker use.
Collapse
Affiliation(s)
- Ozan Demirel
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| | - Alexander E. Berezin
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
- Internal Medicine Department, Zaporozhye State Medical University, 69035 Zaporozhye, Ukraine
| | - Moritz Mirna
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| | - Elke Boxhammer
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| | - Sarah X. Gharibeh
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| | - Uta C. Hoppe
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| | - Michael Lichtenauer
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (O.D.); (M.M.); (E.B.); (S.X.G.); (U.C.H.); (M.L.)
| |
Collapse
|
2
|
Karaliūtė R, Leleika A, Apanavičiūtė I, Kazakevičius T, Mizarienė V, Zabiela V, Kavoliūnienė A, Ragaišytė N, Urbonienė D, Šakalytė G. Risk Factors of Early Atrial Fibrillation Recurrence Following Electrical Cardioversion When Left Ventricular Ejection Fraction Is Preserved. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:1053. [PMID: 36013520 PMCID: PMC9416115 DOI: 10.3390/medicina58081053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 07/22/2022] [Accepted: 07/30/2022] [Indexed: 11/24/2022]
Abstract
Background and objectives: To identify clinical, echocardiographic, and laboratory parameters that affect the early recurrence of atrial fibrillation (AF) after restoring sinus rhythm (SR) by electrical cardioversion (ECV), and to determine whether left atrial (LA) strain, as a noninvasive indicator reflecting fibrosis, is associated with laboratory indicators affecting the development of fibrosis, interleukin 6 (IL-6) or tumor necrosis factor α (TNF-α). Materials and Methods: The study included 92 persistent AF patients who underwent elective ECV. The effective maintenance of SR was evaluated after 40 ± 10 days of ECV. Echocardiography, inflammatory markers (high-sensitivity c-reactive protein (hs-CRP), IL-6, and TNF-α), and natriuretic peptides (N-terminal pro b-type natriuretic peptide (NT-proBNP) and N-terminal pro a-type natriuretic peptide (NT-proANP)) were assessed. Results: After a 40 ± 10 days observation period, 51 patients (55.4%) were in SR. Patients with AF recurrence had a significantly longer duration of AF (p = 0.008) and of arterial hypertension (p = 0.035), lower LA ejection fraction (p = 0.009), lower LA strain (p < 0.0001), higher left ventricular global longitudinal strain (p = 0.001), and a higher E/e‘ ratio (p < 0.0001). LA strain was an independent predictor of early AF recurrence (OR: 0.65; 95% Cl 0.5−0.9, p = 0.004). LA strain < 11.85% predicted AF recurrence with 70% sensitivity and 88% specificity (AUC 0.855, 95% CI 0.77−0.94, p < 0.0001). LA strain demonstrated the association with NT-proBNP (r = −0.489, p < 0.0001) and NT-proANP (r = −0.378, p = 0.002), as well as with hs-CRP (r = −0.243, p = 0.04). Conclusions: LA strain appeared to be the most accurate predictor of early AF recurrence after ECV in patients with persistent AF. LA strain inversely correlated with NT-proBNP and NT-proANP, but no significant association with any of the inflammatory markers was identified.
Collapse
Affiliation(s)
- Rasa Karaliūtė
- Laboratory of Behavioural Medicine, Neuroscience Institute, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
| | - Arnoldas Leleika
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
- Medicine Faculty, Medicine Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Ieva Apanavičiūtė
- Medicine Faculty, Medicine Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Tomas Kazakevičius
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
| | - Vaida Mizarienė
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
| | - Vytautas Zabiela
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Aušra Kavoliūnienė
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
| | - Nijolė Ragaišytė
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
| | - Daiva Urbonienė
- Department of Laboratory Medicine, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| | - Gintarė Šakalytė
- Department of Cardiology, Medical Academy, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
- Kaunas Region Society of Cardiology, 50009 Kaunas, Lithuania
- Institute of Cardiology, Lithuanian University of Health Sciences, 50009 Kaunas, Lithuania
| |
Collapse
|
3
|
Hu D, Jiang J, Ding B, Xue K, Sun X, Qian S. Mechanical Strain Regulates Myofibroblast Differentiation of Human Scleral Fibroblasts by YAP. Front Physiol 2021; 12:712509. [PMID: 34658907 PMCID: PMC8514697 DOI: 10.3389/fphys.2021.712509] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/30/2021] [Indexed: 12/14/2022] Open
Abstract
Scleral extracellular matrix (ECM) remodeling is thought to play a critical role in the pathogenesis of glaucoma. Mechanical strain induced by elevated intraocular pressure can promote myofibroblast differentiation of fibroblasts and result in scleral ECM remodeling; however, the underlying mechanism remains poorly understood. Yes-associated protein (YAP) is a mechanosensory protein and the key downstream transcriptional effector of the Hippo signaling pathway. Here, we investigated the role of YAP in mechanical strain-induced myofibroblast transformation during glaucoma scleral ECM remodeling. Integrative bioinformatics analyses were performed to identify the key pathways for the ECM remodeling of the sclera in glaucoma. Sprague–Dawley rats were used to establish a chronic ocular hypertension model, and the expression of collagen type I (COL1) and YAP in the sclera was analyzed by immunohistochemical analysis and Western blotting. Furthermore, human scleral fibroblasts (HSFs) were cultured and subjected to mechanical strain. In groups with or without the YAP siRNA or YAP inhibitor, cell proliferation, migration capacity, and the expression levels of YAP, COL1, and α-smooth muscle actin (α-SMA) were evaluated by Cell Counting Kit-8 assay, scratch assay, and Western blotting. The interactions between YAP and Smad3 were demonstrated by coimmunoprecipitation, and the expression levels of COL1 and α-SMA were evaluated in groups treated with or without the Smad3 inhibitor. We first revealed that the Hippo signaling pathway may be involved in mechanical strain-induced scleral ECM remodeling through bioinformatics analysis. Furthermore, the in vivo study showed upregulated YAP, COL1, and α-SMA expression in the hypertensive sclera of rats. In vitro, mechanical strain increased YAP and COL1 expression in HSFs and promoted myofibroblast differentiation. After YAP knockdown or inhibition with verteporfin, mechanical strain-induced fibrotic changes in HSFs were markedly suppressed. Additionally, YAP showed a protein interaction with Smad3, and the upregulation of a-SMA and COL1 in response to mechanical strain was also significantly downregulated following the inhibition of Smad3. In conclusion, mechanical strain activated scleral myofibroblast differentiation via YAP. The YAP pathway may play an important role in regulating scleral myofibroblast differentiation and ECM remodeling of the sclera in glaucoma.
Collapse
Affiliation(s)
- Di Hu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China.,Department of Ophthalmology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Junhong Jiang
- The Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Baiyang Ding
- Spine Research Center of Wannan Medical College, Wuhu, China
| | - Kang Xue
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China.,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shaohong Qian
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| |
Collapse
|
4
|
Chow A, McCrea L, Kimball E, Schaub J, Quigley H, Pitha I. Dasatinib inhibits peripapillary scleral myofibroblast differentiation. Exp Eye Res 2020; 194:107999. [PMID: 32179077 DOI: 10.1016/j.exer.2020.107999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/11/2020] [Accepted: 03/09/2020] [Indexed: 12/22/2022]
Abstract
Scleral fibroblast activation occurs in glaucomatous and myopic eyes. Here we perform an unbiased screen to identify kinase inhibitors that reduce fibroblast activation to diverse stimuli in vitro and to in vivo intraocular pressure (IOP) elevation. Primary cultures of peripapillary scleral (PPS) fibroblasts from two human donors were screened using a library of 80 kinase inhibitors to identify compounds that inhibit TGFβ-induced extracellular matrix (ECM) synthesis. Inhibition of myofibroblast differentiation was verified by alpha smooth muscle actin (αSMA) immunoblot and collagen contraction assay. Inhibition of IOP-induced scleral fibroblast proliferation was assessed by ELISA assay for proliferating cell nuclear antigen (PCNA). The initial screen identified 7 inhibitors as showing>80% reduction in ECM binding. Three kinase inhibitors were verified to reduce TGFβ-induced αSMA expression and cellular contractility (rottlerin, PP2, tyrphostin 9). The effect of three Src inhibitors, bosutinib, dasatinib, and SU-6656, on myofibroblast differentiation was evaluated, with only dasatinib significantly inhibiting TGFβ-induced ECM synthesis, αSMA expression, and cellular contractility at nanomolar dosages. Subconjunctival injection of dasatinib reduced IOP-induced scleral fibroblast proliferation compared to control (4.9 ± 11.1 ng/sclera with 0.1 μM versus 88.7 ± 38.6 ng/sclera in control, P < 0.0001). Dasatinib inhibits scleral myofibroblast differentiation and there is pharmacologic evidence that this inhibition is not solely due to Src-kinase inhibition.
Collapse
Affiliation(s)
- Amanda Chow
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Liam McCrea
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Elizabeth Kimball
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Julie Schaub
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Harry Quigley
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Ian Pitha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
| |
Collapse
|
5
|
Zhang X, Lu H, Xie S, Wu C, Guo Y, Xiao Y, Zheng S, Zhu H, Zhang Y, Bai Y. Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in kidneys via proliferation-related signalling pathways. Br J Pharmacol 2019; 176:4745-4759. [PMID: 31454852 PMCID: PMC6965682 DOI: 10.1111/bph.14842] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Renal fibrosis acts as the common pathway leading to the development of end-stage renal disease. Previous studies have shown that resveratrol has anti-fibrotic activity, but its potential molecular mechanisms of action are not well understood. EXPERIMENTAL APPROACH The anti-fibrotic effects of resveratrol were assayed in a rat model of unilateral ureteral obstruction (UUO) in vivo and in fibroblasts and tubular epithelial cells (TECs) stimulated by TGF-β1 in vitro. Gene and protein expression levels were analysed by PCR, Western blotting, and immunohistochemical staining. KEY RESULTS Resveratrol inhibits the myofibroblastic phenotype and fibrosis formation in UUO kidneys by targeting fibroblast-myofibroblast differentiation (FMD) and epithelial-mesenchymal transition (EMT). The anti-fibrotic effects of resveratrol correlated with decreased proliferation of TECs in the interstitium and tubules, resulting in suppressed activity of the proliferation-related signalling pathways, including that of the MAPK, PI3K/Akt, Wnt/β-catenin, and JAK2/STAT3 pathways. Resveratrol treatment suppressed TGF-β1-induced FMD and the expression of the myofibroblastic phenotype in fibroblasts in vitro by antagonizing the activation of proliferation-related signalling. Similarly, TGF-β1-mediated overactivation of the proliferation-related signalling in TECs induced EMT, and the myofibroblastic phenotype was suppressed by resveratrol. The anti-fibrotic and anti-proliferative effects of resveratrol were associated with the inactivation of Smad2/3 signalling and resulted in a partial reversal of FMD and EMT and the inhibition of the myofibroblastic phenotype. CONCLUSIONS AND IMPLICATIONS Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in vivo and in vitro via proliferation-related pathways, making it a potential therapeutic agent for preventing renal fibrosis.
Collapse
Affiliation(s)
- Xing Zhang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
- Zhejiang University School of MedicineHangzhouChina
| | - Hong Lu
- Department of Laboratory MedicineThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | | | - Cunzao Wu
- Department of TransplantationThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Yangyang Guo
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Yanyi Xiao
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Shizhang Zheng
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Hengyue Zhu
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Yan Zhang
- Department of TransplantationThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
- Institute of Kidney Health, Center for Health AssessmentWenzhou Medical UniversityWenzhouChina
| | - Yongheng Bai
- Key Laboratory of Diagnosis and Treatment of Severe Hepato‐Pancreatic Diseases of Zhejiang ProvinceThe First Affiliated Hospital of Wenzhou Medical UniversityWenzhouChina
- Institute of Kidney Health, Center for Health AssessmentWenzhou Medical UniversityWenzhouChina
| |
Collapse
|
6
|
Moreno-Ruiz LA, Madrid-Miller A, Martínez-Flores JE, González-Hermosillo JA, Arenas-Fonseca J, Zamorano-Velázquez N, Mendoza-Pérez B. Left atrial longitudinal strain by speckle tracking as independent predictor of recurrence after electrical cardioversion in persistent and long standing persistent non-valvular atrial fibrillation. Int J Cardiovasc Imaging 2019; 35:1587-1596. [PMID: 30993507 PMCID: PMC6700045 DOI: 10.1007/s10554-019-01597-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 04/03/2019] [Indexed: 11/01/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in humans. After successful cardioversion, there is a recurrence of 60% due to atrial remodeling, and it has been shown that the global peak atrial longitudinal strain (GPALS) is decreased in these subjects. The aim of this study was to evaluate the predictive value of GPALS for AF recurrence. A prospective cohort of patients with persistent (PnVAF) and long standing persistent non-valvular AF (LSPnVAF) which underwent electrical cardioversion was evaluated with standard echocardiographic variables and GPALS quantification. The primary endpoint was AF recurrence at 6 months. We included PnVAF (n = 50, aged 68.4 ± 10.2 years, female 46%, lasted AF 6 months) and LSPnVAF (n = 81, aged 66.5 ± 13.1 years, female 36%, lasted AF 18 months). At 6 months there were a 68% of recurrence of AF in PnVAF and 53% in LSPnVAF group. GPALS was lower in recurrence 7.8 ± 2.0% versus 21.2 ± 8.9% (p < 0.001) for PnVAF and 7.3 ± 2.7% versus 20.7 ± 7.6% (p < 0.001) in LSPnVAF. GPALS ≤ 10.75% discriminates recurrence at 6 months with a sensitivity of 85%, specificity 99%, PPV 85%, NPV 90%, LR + 8.5 and LR- 0.17. The independent predictors of recurrence in PnVAF were GPALS ≤ 10.75% HR 8.89 [(2.2-35.7), p < 0.01] meanwhile in LSPnVAF were age HR 1.039 [(1.007-1.071), p = 0.01], and GPALS ≤ 10.75% HR 28.1 [(7.2-109.1), p < 0.001]. In subjects with PnVAF and LSPnVAF with successful electrical cardioversion, GPALS ≤ 10.75% predicts arrhythmia recurrence at 6-month follow-up.
Collapse
Affiliation(s)
- Luis Antonio Moreno-Ruiz
- Division of Cardiology, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico.
| | - Alejandra Madrid-Miller
- Direction of Education and Research, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico
| | - Jerónimo Enrique Martínez-Flores
- Department of Electrophysiology, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico
| | - Jesús Antonio González-Hermosillo
- Medical Subadrees of Innovation and Development Project, Instituto Nacional de Cardiología "Ignacio Chávez", 1 Juan Badiano, Sección XVI, Tlalpan, 14080, Mexico City, Mexico
| | - Jorge Arenas-Fonseca
- Department of Echocardiography, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico
| | - Noé Zamorano-Velázquez
- Department of Echocardiography, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico
| | - Beatriz Mendoza-Pérez
- Division of Cardiology, UMAE Hospital de Cardiología, Centro Médico Nacional Siglo XXI, IMSS, 330 Cuauhtémoc Av, Doctores, Cuauhtémoc, 06720, Mexico City, Mexico
| |
Collapse
|
7
|
Kaur K, Jalife J. Is TGF-β 1 (Transforming Growth Factor-β 1) an Enabler of Myofibroblast-Cardiomyocyte Cross Talk? Circ Arrhythm Electrophysiol 2019; 10:e005289. [PMID: 28500179 DOI: 10.1161/circep.117.005289] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kuljeet Kaur
- From the Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor (K.K., J.J.); Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain (J.J.); and Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares, Spain (J.J.)
| | - José Jalife
- From the Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor (K.K., J.J.); Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain (J.J.); and Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares, Spain (J.J.).
| |
Collapse
|
8
|
Pitha I, Oglesby E, Chow A, Kimball E, Pease ME, Schaub J, Quigley H. Rho-Kinase Inhibition Reduces Myofibroblast Differentiation and Proliferation of Scleral Fibroblasts Induced by Transforming Growth Factor β and Experimental Glaucoma. Transl Vis Sci Technol 2018; 7:6. [PMID: 30479877 PMCID: PMC6238981 DOI: 10.1167/tvst.7.6.6] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/16/2018] [Indexed: 01/07/2023] Open
Abstract
Purpose We evaluated prevention of transforming growth factor β (TGFβ)–induced transdifferentiation of cultured scleral fibroblasts to myofibroblasts by rho-associated protein kinase (ROCK) inhibitors. Additionally, we tested whether local delivery of ROCK inhibitors reduced scleral fibroblast proliferation in response to chronic intraocular pressure (IOP) elevation. Methods Primary human peripapillary sclera (PPS) fibroblasts were cultured and treated with TGFβ to induce myofibroblast transdifferentiation, as determined by immunoblot assessment of α smooth muscle actin (SMA) levels and collagen gel contraction. Cells were treated with the ROCK inhibitors Y27632, fasudil, and H1152 before TGFβ treatment. ROCK activity in TGFβ-treated fibroblasts and sclera from ocular hypertensive mice was assessed by measuring phosphorylation of the ROCK substrate MYPT1 at Thr696. Fibroblast proliferation following IOP elevation and ROCK inhibitor treatment was assessed by an enzyme-linked immunosorbent (ELISA) assay. Results ROCK inhibitors H1152 (10μM), Y27632 (10 μM), and fasudil (5μM) reduced SMA expression 72%, 85%, and 68%, respectively. Collagen gel contraction was reduced by 36% (P < 0.001), 27% (P = 0.0003), and 33% (P = 0.0019) following treatment with fasudil (25 μM), Y27632 (10 μM), and H1152 (10μM). ROCK activity induced by TGFβ rose 4.74 ± 1.9 times over control at 4 hours (P = 0.0004) and 2.4 ± 0.47-fold (P = 0.0016) in sclera after IOP elevation. Proliferation of scleral fibroblasts after chronic IOP elevation was reduced 77% by Y27632 (P = 0.001) and 84% by fasudil (P = 0.0049). Conclusions ROCK inhibitors reduce TGFβ-induced myofibroblast transdifferentiation and glaucoma-induced scleral cell proliferation. Translational Relevance These findings suggest altered fibroblast activity promoted by ROCK inhibitors could modify scleral biomechanics and be relevant to glaucoma treatment.
Collapse
Affiliation(s)
- Ian Pitha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ericka Oglesby
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Amanda Chow
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elizabeth Kimball
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mary Ellen Pease
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Julie Schaub
- Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Harry Quigley
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
9
|
Computational Approaches to Understanding the Role of Fibroblast-Myocyte Interactions in Cardiac Arrhythmogenesis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:465714. [PMID: 26601107 PMCID: PMC4637154 DOI: 10.1155/2015/465714] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/10/2015] [Accepted: 04/29/2015] [Indexed: 11/18/2022]
Abstract
The adult heart is composed of a dense network of cardiomyocytes surrounded by nonmyocytes, the most
abundant of which are cardiac fibroblasts. Several cardiac diseases, such as myocardial infarction or dilated
cardiomyopathy, are associated with an increased density of fibroblasts, that is, fibrosis. Fibroblasts play a
significant role in the development of electrical and mechanical dysfunction of the heart; however the underlying
mechanisms are only partially understood. One widely studied mechanism suggests that fibroblasts produce
excess extracellular matrix, resulting in collagenous septa. These collagenous septa slow propagation, cause
zig-zag conduction paths, and decouple cardiomyocytes resulting in a substrate for arrhythmia. Another
emerging mechanism suggests that fibroblasts promote arrhythmogenesis through direct electrical interactions
with cardiomyocytes via gap junctions. Due to the challenges of investigating fibroblast-myocyte coupling in
native cardiac tissue, computational modeling and in vitro experiments have facilitated the investigation into the
mechanisms underlying fibroblast-mediated changes in cardiomyocyte action potential morphology, conduction
velocity, spontaneous excitability, and vulnerability to reentry. In this paper, we summarize the major findings of
the existing computational studies investigating the implications of fibroblast-myocyte interactions in the normal
and diseased heart. We then present investigations from our group into the potential role of voltage-dependent
gap junctions in fibroblast-myocyte interactions.
Collapse
|
10
|
Meens MJ, Kwak BR, Duffy HS. Role of connexins and pannexins in cardiovascular physiology. Cell Mol Life Sci 2015; 72:2779-92. [PMID: 26091747 PMCID: PMC11113959 DOI: 10.1007/s00018-015-1959-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 12/26/2022]
Abstract
Connexins and pannexins form connexons, pannexons and membrane channels, which are critically involved in many aspects of cardiovascular physiology. For that reason, a vast number of studies have addressed the role of connexins and pannexins in the arterial and venous systems as well as in the heart. Moreover, a role for connexins in lymphatics has recently also been suggested. This review provides an overview of the current knowledge regarding the involvement of connexins and pannexins in cardiovascular physiology.
Collapse
Affiliation(s)
- Merlijn J. Meens
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
| | - Brenda R. Kwak
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
| | | |
Collapse
|
11
|
Xiao X, Huang C, Zhao C, Gou X, Senavirathna LK, Hinsdale M, Lloyd P, Liu L. Regulation of myofibroblast differentiation by miR-424 during epithelial-to-mesenchymal transition. Arch Biochem Biophys 2014; 566:49-57. [PMID: 25524739 DOI: 10.1016/j.abb.2014.12.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/21/2014] [Accepted: 12/08/2014] [Indexed: 12/15/2022]
Abstract
Idiopathic pulmonary fibrosis (IPF) is one of the most common and severe interstitial lung diseases. Epithelial-to-mesenchymal transition (EMT) is a process whereby epithelial cells undergo transition to a mesenchymal phenotype. This process has been shown to contribute to IPF. MicroRNAs (miRNAs) are small non-coding RNAs of 18-24 nucleotides in length which regulate gene expression. Several studies have implicated miRNAs in EMT; however, specific miRNAs that regulate EMT in IPF have not yet been identified. In this study, we identified 6 up-regulated and 3 down-regulated miRNAs in a human lung epithelial cell EMT model using miRNA microarray and real-time PCR. Overexpression of one of these up-regulated miRNAs, miR-424, increased the expression of α-smooth muscle actin, an indicator of myofibroblast differentiation, but had no effects on the epithelial or mesenchymal cell markers. miR-424 enhanced the activity of the TGF-β signaling pathway, as demonstrated by a luciferase reporter assay. Further experiments showed that miR-424 decreased the protein expression of Smurf2, a negative regulator of TGF-β signaling, indicating that miR-424 exerts a forward regulatory loop in the TGF-β signaling pathway. Our results suggest that miR-424 regulates the myofibroblast differentiation during EMT by potentiating the TGF-β signaling pathway, likely through Smurf2.
Collapse
Affiliation(s)
- Xiao Xiao
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Chaoqun Huang
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Chunling Zhao
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA; Department of Physiology, Luzhou Medical College, Luzhou, Sichuan, People's Republic of China
| | - Xuxu Gou
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Lakmini K Senavirathna
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Myron Hinsdale
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Pamela Lloyd
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Lin Liu
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| |
Collapse
|
12
|
Veeraraghavan R, Gourdie RG, Poelzing S. Mechanisms of cardiac conduction: a history of revisions. Am J Physiol Heart Circ Physiol 2014; 306:H619-27. [PMID: 24414064 DOI: 10.1152/ajpheart.00760.2013] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac conduction is the process by which electrical excitation spreads through the heart, triggering individual myocytes to contract in synchrony. Defects in conduction disrupt synchronous activation and are associated with life-threatening arrhythmias in many pathologies. Therefore, it is scarcely surprising that this phenomenon continues to be the subject of active scientific inquiry. Here we provide a brief review of how the conceptual understanding of conduction has evolved over the last century and highlight recent, potentially paradigm-shifting developments.
Collapse
Affiliation(s)
- Rengasayee Veeraraghavan
- Virginia Tech Carilion Research Institute, and Center for Heart and Regenerative Medicine, Virginia Polytechnic University, Roanoke, Virginia; and
| | | | | |
Collapse
|
13
|
Acute slowing of cardiac conduction in response to myofibroblast coupling to cardiomyocytes through N-cadherin. J Mol Cell Cardiol 2014; 68:29-37. [PMID: 24412534 DOI: 10.1016/j.yjmcc.2013.12.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 12/24/2013] [Accepted: 12/31/2013] [Indexed: 01/06/2023]
Abstract
The electrophysiological consequences of cardiomyocyte and myofibroblast interactions remain unclear, and the contribution of mechanical coupling between these two cell types is still poorly understood. In this study, we examined the time course and mechanisms by which addition of myofibroblasts activated by transforming growth factor-beta (TGF-β) influence the conduction velocity (CV) of neonatal rat ventricular cell monolayers. We observed that myofibroblasts affected CV within 30 min of contact and that these effects were temporally correlated with membrane deformation of cardiomyocytes by the myofibroblasts. Expression of dominant negative RhoA in the myofibroblasts impaired both myofibroblast contraction and myofibroblast-induced slowing of cardiac conduction, whereas overexpression of constitutive RhoA had little effect. To determine the importance of mechanical coupling between these cell types, we examined the expression of the two primary cadherins in the heart (N- and OB-cadherin) at cell-cell contacts formed between myofibroblasts and cardiomyocytes. Although OB-cadherin was frequently found at myofibroblast-myofibroblast contacts, very little expression was observed at myofibroblast-cardiomyocyte contacts. The myofibroblast-induced slowing of cardiac conduction was not prevented by silencing of OB-cadherin in the myofibroblasts, and could be reversed by inhibitors of mechanosensitive channels (gadolinium or streptomycin) and cellular contraction (blebbistatin). In contrast, N-cadherin expression was commonly observed at myofibroblast-cardiomyocyte contacts, and silencing of N-cadherin in myofibroblasts prevented the myofibroblast-dependent slowing of cardiac conduction. We propose that myofibroblasts can impair the electrophysiological function of cardiac tissue through the application of contractile force to the cardiomyocyte membrane via N-cadherin junctions.
Collapse
|
14
|
Mehner C, Radisky DC. Triggering the landslide: The tumor-promotional effects of myofibroblasts. Exp Cell Res 2013; 319:1657-62. [PMID: 23528452 DOI: 10.1016/j.yexcr.2013.03.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 03/13/2013] [Indexed: 12/30/2022]
Abstract
Cancers become significantly more dangerous when the tumor progresses from in situ, or contained, to an invasive state, in which the cancer cells acquire the ability to pass through the surrounding basement membrane (BM), a specialized extracellular matrix (ECM) that provides structure and contextual information to the underlying tissue. While the majority of tumors are carcinomas, derived from epithelial cells, it is the stromal cells surrounding the epithelial-derived tumor cells, including fibroblasts and myofibroblasts, vasculature, and immune cells, that are largely responsible for the production and remodeling of the ECM. Here, we will discuss myofibroblasts as key effectors of tumor progression, focusing on recent advances in breast and pancreatic carcinoma, showing how myofibroblasts may function properly in normal tissue remodeling and wound-healing processes, how in the tumor context they can drive cancer invasion and metastasis, and how the pathogenic functions of myofibroblasts may be targeted therapeutically.
Collapse
Affiliation(s)
- Christine Mehner
- Mayo Clinic Cancer Center, Jacksonville, FL 32225, United States.
| | - Derek C Radisky
- Mayo Clinic Cancer Center, Jacksonville, FL 32225, United States.
| |
Collapse
|
15
|
Kaur K, Zarzoso M, Ponce-Balbuena D, Guerrero-Serna G, Hou L, Musa H, Jalife J. TGF-β1, released by myofibroblasts, differentially regulates transcription and function of sodium and potassium channels in adult rat ventricular myocytes. PLoS One 2013; 8:e55391. [PMID: 23393573 PMCID: PMC3564808 DOI: 10.1371/journal.pone.0055391] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/21/2012] [Indexed: 12/19/2022] Open
Abstract
Cardiac injury promotes fibroblasts activation and differentiation into myofibroblasts, which are hypersecretory of multiple cytokines. It is unknown whether any of such cytokines are involved in the electrophysiological remodeling of adult cardiomyocytes. We cultured adult cardiomyocytes for 3 days in cardiac fibroblast conditioned medium (FCM) from adult rats. In whole-cell voltage-clamp experiments, FCM-treated myocytes had 41% more peak inward sodium current (INa) density at −40 mV than myocytes in control medium (p<0.01). In contrast, peak transient outward current (Ito) was decreased by ∼55% at 60 mV (p<0.001). Protein analysis of FCM demonstrated that the concentration of TGF-β1 was >3 fold greater in FCM than control, which suggested that FCM effects could be mediated by TGF-β1. This was confirmed by pre-treatment with TGF-β1 neutralizing antibody, which abolished the FCM-induced changes in both INa and Ito. In current-clamp experiments TGF-β1 (10 ng/ml) prolonged the action potential duration at 30, 50, and 90 repolarization (p<0.05); at 50 ng/ml it gave rise to early afterdepolarizations. In voltage-clamp experiments, TGF-β1 increased INa density in a dose-dependent manner without affecting voltage dependence of activation or inactivation. INa density was −36.25±2.8 pA/pF in control, −59.17±6.2 pA/pF at 0.1 ng/ml (p<0.01), and −58.22±6.6 pA/pF at 1 ng/ml (p<0.01). In sharp contrast, Ito density decreased from 22.2±1.2 pA/pF to 12.7±0.98 pA/pF (p<0.001) at 10 ng/ml. At 1 ng/ml TGF-β1 significantly increased SCN5A (NaV1.5) (+73%; p<0.01), while reducing KCNIP2 (Kchip2; −77%; p<0.01) and KCND2 (KV4.2; −50% p<0.05) mRNA levels. Further, the TGF-β1-induced increase in INa was mediated through activation of the PI3K-AKT pathway via phosphorylation of FOXO1 (a negative regulator of SCN5A). TGF-β1 released by myofibroblasts differentially regulates transcription and function of the main cardiac sodium channel and of the channel responsible for the transient outward current. The results provide new mechanistic insight into the electrical remodeling associated with myocardial injury.
Collapse
Affiliation(s)
- Kuljeet Kaur
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Manuel Zarzoso
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Daniela Ponce-Balbuena
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Guadalupe Guerrero-Serna
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Luqia Hou
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Hassan Musa
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - José Jalife
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
| |
Collapse
|
16
|
Bapat A, Nguyen TP, Lee JH, Sovari AA, Fishbein MC, Weiss JN, Karagueuzian HS. Enhanced sensitivity of aged fibrotic hearts to angiotensin II- and hypokalemia-induced early afterdepolarization-mediated ventricular arrhythmias. Am J Physiol Heart Circ Physiol 2012; 302:H2331-40. [PMID: 22467308 DOI: 10.1152/ajpheart.00094.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Unlike young hearts, aged hearts are highly susceptible to early afterdepolarization (EAD)-mediated ventricular fibrillation (VF). This differential may result from age-related structural remodeling (fibrosis) or electrical remodeling of ventricular myocytes or both. We used optical mapping and microelectrode recordings in Langendorff-perfused hearts and patch-clamp recordings in isolated ventricular myocytes from aged (24-26 mo) and young (3-4 mo) rats to assess susceptibility to EADs and VF during either oxidative stress with ANG II (2 μM) or ionic stress with hypokalemia (2.7 mM). ANG II caused EAD-mediated VF in 16 of 19 aged hearts (83%) after 32 ± 7 min but in 0 of 9 young hearts (0%). ANG II-mediated VF was suppressed with KN-93 (Ca(2+)/calmodulin-dependent kinase inhibitor) and the reducing agent N-acetylcysteine. Hypokalemia caused EAD-mediated VF in 11 of 11 aged hearts (100%) after 7.4 ± 0.4 min. In 14 young hearts, however, VF did not occur in 6 hearts (43%) or was delayed in onset (31 ± 22 min, P < 0.05) in 8 hearts (57%). In patch-clamped myocytes, ANG II and hypokalemia (n = 6) induced EADs and triggered activity in both age groups (P = not significant) at a cycle length of >0.5 s. When myocytes of either age group were coupled to a virtual fibroblast using the dynamic patch-clamp technique, EADs arose in both groups at a cycle length of <0.5 s. Aged ventricles had significantly greater fibrosis and reduced connexin43 gap junction density compared with young hearts. The lack of differential age-related sensitivity at the single cell level in EAD susceptibility indicates that increased ventricular fibrosis in the aged heart plays a key role in increasing vulnerability to VF induced by oxidative and ionic stress.
Collapse
Affiliation(s)
- Aneesh Bapat
- Translational Arrhythmia Research Section, University of California-Los Angeles Cardiovascular Research Laboratory, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
Desroches BR, Zhang P, Choi BR, King ME, Maldonado AE, Li W, Rago A, Liu G, Nath N, Hartmann KM, Yang B, Koren G, Morgan JR, Mende U. Functional scaffold-free 3-D cardiac microtissues: a novel model for the investigation of heart cells. Am J Physiol Heart Circ Physiol 2012; 302:H2031-42. [PMID: 22427522 DOI: 10.1152/ajpheart.00743.2011] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
To bridge the gap between two-dimensional cell culture and tissue, various three-dimensional (3-D) cell culture approaches have been developed for the investigation of cardiac myocytes (CMs) and cardiac fibroblasts (CFs). However, several limitations still exist. This study was designed to develop a cardiac 3-D culture model with a scaffold-free technology that can easily and inexpensively generate large numbers of microtissues with cellular distribution and functional behavior similar to cardiac tissue. Using micromolded nonadhesive agarose hydrogels containing 822 concave recesses (800 μm deep × 400 μm wide), we demonstrated that neonatal rat ventricular CMs and CFs alone or in combination self-assembled into viable (Live/Dead stain) spherical-shaped microtissues. Importantly, when seeded simultaneously or sequentially, CMs and CFs self-sorted to be interspersed, reminiscent of their myocardial distribution, as shown by cell type-specific CellTracker or antibody labeling. Microelectrode recordings and optical mapping revealed characteristic triangular action potentials (APs) with a resting membrane potential of -66 ± 7 mV (n = 4) in spontaneously contracting CM microtissues. Under pacing, optically mapped AP duration at 90% repolarization and conduction velocity were 100 ± 30 ms and 18.0 ± 1.9 cm/s, respectively (n = 5 each). The presence of CFs led to a twofold AP prolongation in heterogenous microtissues (CM-to-CF ratio of 1:1). Importantly, Ba(2+)-sensitive inward rectifier K(+) currents and Ca(2+)-handling proteins, including sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a, were detected in CM-containing microtissues. Furthermore, cell type-specific adenoviral gene transfer was achieved, with no impact on microtissue formation or cell viability. In conclusion, we developed a novel scaffold-free cardiac 3-D culture model with several advancements for the investigation of CM and CF function and cross-regulation.
Collapse
Affiliation(s)
- B R Desroches
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital, Providence, RI 02903, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Note on a possible proarrhythmic property of antiarrhythmic drugs aimed at improving gap-junction coupling. Biophys J 2012; 102:231-7. [PMID: 22339859 DOI: 10.1016/j.bpj.2011.11.4015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 11/18/2011] [Accepted: 11/22/2011] [Indexed: 01/02/2023] Open
Abstract
Reduced conduction velocity (CV) in the myocardium is well known to increase the probability of arrhythmia and can be caused by structural changes, reduced excitability of individual myocytes, or decreased electrical coupling in the tissue. Recently, investigators have developed antiarrhythmic drugs that target the connections between individual myocytes with the goal of restoring tissue CV, specifically through increasing gap-junction coupling. In a simple but qualitatively relevant mathematical model, we show here that the introduction of a drug that improves intercellular conductance will indeed increase the CV. However, conditions that would require such a drug, such as fibrotic remodeling, may also increase the load of fibroblasts. Fibroblasts may couple to myocytes in much the same way as myocytes couple to each other, and therefore the use of such an agent may also improve coupling between myocytes and fibroblasts. We present numerical examples illustrating that when the load of coupled fibroblasts on myocytes is low or nonexistent, the drug works as expected, i.e., the drug increases CV. On the other hand, when the fibroblast load is high, changes in CV are nonmonotonic, i.e., the CV first increases and then decreases with an increase in dosage. The existence of coupled fibroblasts may therefore impair the effect of the drug, and under unfortunate conditions may be proarrhythmic.
Collapse
|