1
|
Gluvic Z, Obradovic M, Stewart AJ, Essack M, Pitt SJ, Samardzic V, Soskic S, Gojobori T, Isenovic ER. Levothyroxine Treatment and the Risk of Cardiac Arrhythmias - Focus on the Patient Submitted to Thyroid Surgery. Front Endocrinol (Lausanne) 2021; 12:758043. [PMID: 34803920 PMCID: PMC8600254 DOI: 10.3389/fendo.2021.758043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 02/05/2023] Open
Abstract
Levothyroxine (LT4) is used to treat frequently encountered endocrinopathies such as thyroid diseases. It is regularly used in clinical (overt) hypothyroidism cases and subclinical (latent) hypothyroidism cases in the last decade. Suppressive LT4 therapy is also part of the medical regimen used to manage thyroid malignancies after a thyroidectomy. LT4 treatment possesses dual effects: substituting new-onset thyroid hormone deficiency and suppressing the local and distant malignancy spreading in cancer. It is the practice to administer LT4 in less-than-high suppressive doses for growth control of thyroid nodules and goiter, even in patients with preserved thyroid function. Despite its approved safety for clinical use, LT4 can sometimes induce side-effects, more often recorded with patients under treatment with LT4 suppressive doses than in unintentionally LT4-overdosed patients. Cardiac arrhythmias and the deterioration of osteoporosis are the most frequently documented side-effects of LT4 therapy. It also lowers the threshold for the onset or aggravation of cardiac arrhythmias for patients with pre-existing heart diseases. To improve the quality of life in LT4-substituted patients, clinicians often prescribe higher doses of LT4 to reach low normal TSH levels to achieve cellular euthyroidism. In such circumstances, the risk of cardiac arrhythmias, particularly atrial fibrillation, increases, and the combined use of LT4 and triiodothyronine further complicates such risk. This review summarizes the relevant available data related to LT4 suppressive treatment and the associated risk of cardiac arrhythmia.
Collapse
Affiliation(s)
- Zoran Gluvic
- Clinic for Internal Medicine, Department of Endocrinology and Diabetes, Zemun Clinical Hospital, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Milan Obradovic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Alan J. Stewart
- School of Medicine, University of St Andrews, St Andrews, United Kingdom
| | - Magbubah Essack
- King Abdullah University of Science and Technology (KAUST), Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia
| | - Samantha J. Pitt
- School of Medicine, University of St Andrews, St Andrews, United Kingdom
| | - Vladimir Samardzic
- Clinic for Internal Medicine, Department of Endocrinology and Diabetes, Zemun Clinical Hospital, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Sanja Soskic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Takashi Gojobori
- King Abdullah University of Science and Technology (KAUST), Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia
| | - Esma R. Isenovic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| |
Collapse
|
2
|
Amino M, Yoshioka K, Kamada T, Furusawa Y. The Potential Application of Heavy Ion Beams in the Treatment of Arrhythmia: The Role of Radiation-Induced Modulation of Connexin43 and the Sympathetic Nervous System. Int J Part Ther 2018; 5:140-150. [PMID: 31773026 DOI: 10.14338/ijpt-18-00022.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/12/2018] [Indexed: 11/21/2022] Open
Abstract
It has been known that heart disease-such as myocardial infarction (MI), cardiac hypertrophy, or heart failure-alters the molecular structure and function of the gap junction, which can lead to an abnormal heart rhythm. Radiation has been shown to modulate intercellular communication in the skin and lungs by increasing connexin43 (Cx43) expression. Understanding how Cx43 upregulation is induced in a diseased heart can help provide a new perspective to radiation therapy for arrhythmias. In a recent study with rabbits after MI, carbon ions were accelerated to 290 MeV/u and extracted in the air; a biologically (cell kill) uniform 6-cm spread-out Bragg peak beam was generated, and beam tissue depth was set to 30 mm with energy degraders to the depth position. Targeted heavy ion irradiation (THIR) with 15 Gy to the left ventricle increased Cx43 expression, improved conductivity, decreased the spatial heterogeneity of repolarization, and reduced the vulnerability of rabbit hearts to ventricular arrhythmias after MI. In clinically normal rabbits, THIR > = 10 Gy caused a significant dose-dependent increase of Cx43 protein and messenger RNA 2 weeks after irradiation. The left (irradiated) and right (nonirradiated) ventricles exhibited circumferential upregulation of Cx43 lasting for at least 1 year. There were no significant changes in electrocardiograms and echocardiograms, indicating no apparent injury for 1 year. A single exposure of 135 MeV/u THIR with 15 Gy to a dog heart attenuated vulnerability to ventricular arrhythmia after the induction of MI for at least 1 year through the modulation of Cx43 expression. This long-lasting remodeling effect on gap junctions may lay the groundwork to novel therapies against life-threatening ventricular arrhythmias in structural heart disease. To date, there have been few investigations into the effects of carbon-ion irradiation on electrophysiological properties in the human heart. Patients with mediastinum cancer were investigated for 5 years after treatment that included irradiation to the heart, and investigators found that carbon-ion beam irradiation to the heart is not immediately cardiotoxic and demonstrates consistent signals of arrhythmia reduction. Its practical application in non-cancer treatment, such as in arrhythmia treatment, is highly anticipated.
Collapse
Affiliation(s)
- Mari Amino
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | - Koichiro Yoshioka
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | - Tadashi Kamada
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | | |
Collapse
|
3
|
Szeiffová Bačová B, Egan Beňová T, Viczenczová C, Soukup T, Rauchová H, Pavelka S, Knezl V, Barančík M, Tribulová N. Cardiac connexin-43 and PKC signaling in rats with altered thyroid status without and with omega-3 fatty acids intake. Physiol Res 2017; 65 Suppl 1:S77-90. [PMID: 27643942 DOI: 10.33549/physiolres.933413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Thyroid hormones are powerful modulators of heart function and susceptibility to arrhythmias via both genomic and non-genomic actions. We aimed to explore expression of electrical coupling protein connexin-43 (Cx43) in the heart of rats with altered thyroid status and impact of omega-3 polyunsaturated fatty acids (omega-3) supplementation. Adult male Lewis rats were divided into following six groups: euthyroid controls, hyperthyroid (treated with T(3)) and hypothyroid (treated with methimazol) with or without six-weeks lasting supplementation with omega-3 (20 mg/100 g/day). Left and right ventricles, septum and atria were used for immunoblotting of Cx43 and protein kinase C (PKC). Total expression of Cx43 and its phosphorylated forms were significantly increased in all heart regions of hypothyroid rats compared to euthyroid controls. In contrast, the total levels of Cx43 and its functional phosphorylated forms were decreased in atria and left ventricle of hyperthyroid rats. In parallel, the expression of PKC epsilon that phosphorylates Cx43, at serine 368, was increased in hypothyroid but decreased in hyperthyroid rat hearts. Omega-3 intake did not significantly affect either Cx43 or PKC epsilon alterations. In conclusion, there is an inverse relationship between expression of cardiac Cx43 and the levels of circulating thyroid hormones. It appears that increased propensity of hyperthyroid while decreased of hypothyroid individuals to malignant arrhythmias may be in part attributed to the changes in myocardial Cx43.
Collapse
Affiliation(s)
- B Szeiffová Bačová
- Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovak Republic.
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Amino M, Yoshioka K, Furusawa Y, Tanaka S, Kawabe N, Hashida T, Tsukada T, Izumi M, Inokuchi S, Tanabe T, Ikari Y. Inducibility of Ventricular Arrhythmia 1 Year Following Treatment with Heavy Ion Irradiation in Dogs with Myocardial Infarction. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2017; 40:379-390. [PMID: 28158934 DOI: 10.1111/pace.13031] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/06/2017] [Accepted: 01/23/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Targeted external heavy ion irradiation (THIR) of rabbit hearts 2 weeks after myocardial infarction (MI) reduced the vulnerability of fatal ventricular tachyarrhythmias (VT/VF) in association with the increased connexin43 (Cx43). Increased Cx43 was maintained for at least 1 year in normal rabbits, but the long-term antiarrhythmic effects in the MI model are unknown. We investigated the propensity for late potentials and VT/VF inducibility. METHODS Intracoronary injection of microspheres was performed to induce nontransmural MI in anesthetized eight beagles. Four beagles were treated with THIR (12 C6+ , 15 Gy) 2 weeks later (MI + THIR group), and four without THIR served as controls (MI group). Signal-averaged electrocardiography, programmed electrical stimulation, immunohistochemical analysis, and echocardiograms were performed at 1 year. RESULTS Filtered QRS duration was exacerbated after MI and remained unchanged for 1 year in the MI group (118 ± 1.4 ms), but significantly returned toward baseline in the MI + THIR group (109 ± 6.9 ms). Similarly, root mean square voltage of the last 40 ms was exacerbated after MI, but recovered after THIR. VT/VF inducibility decreased to 25% in the MI + THIR group compared with 100% in the MI group. Immunostaining Cx43 expression in cardiac tissues significantly increased by 24-45% in the MI + THIR group. Left ventricular ejection fractions remained within the normal range in both groups. CONCLUSION A single exposure of the dog heart to 12 C irradiation attenuated vulnerability to ventricular arrhythmia after the induction of MI for at least 1 year through the modulation of Cx43 expression.
Collapse
Affiliation(s)
- Mari Amino
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | - Koichiro Yoshioka
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | | | - Sachie Tanaka
- Support Center for Medical Research and Education, Tokai University, Shimokasuya, Japan
| | - Noboru Kawabe
- Support Center for Medical Research and Education, Tokai University, Shimokasuya, Japan
| | - Tadashi Hashida
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | | | | | - Sadaki Inokuchi
- Department of Critical Care and Medicine, Tokai University, Isehara, Japan
| | - Teruhisa Tanabe
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| | - Yuji Ikari
- Department of Cardiovascular Medicine, Tokai University, Isehara, Japan
| |
Collapse
|
5
|
Bačová BS, Vinczenzová C, Žurmanová J, Kašparová D, Knezl V, Beňová TE, Pavelka S, Soukup T, Tribulová N. Altered thyroid status affects myocardial expression of connexin-43 and susceptibility of rat heart to malignant arrhythmias that can be partially normalized by red palm oil intake. Histochem Cell Biol 2016; 147:63-73. [DOI: 10.1007/s00418-016-1488-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2016] [Indexed: 01/25/2023]
|
6
|
Asiri AM, Marwani HM, Khan SB, Webster TJ. Understanding greater cardiomyocyte functions on aligned compared to random carbon nanofibers in PLGA. Int J Nanomedicine 2014; 10:89-96. [PMID: 25565806 PMCID: PMC4275055 DOI: 10.2147/ijn.s74173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Previous studies have demonstrated greater cardiomyocyte density on carbon nanofibers (CNFs) aligned (compared to randomly oriented) in poly(lactic-co-glycolic acid) (PLGA) composites. Although such studies demonstrated a closer mimicking of anisotropic electrical and mechanical properties for such aligned (compared to randomly oriented) CNFs in PLGA composites, the objective of the present in vitro study was to elucidate a deeper mechanistic understanding of how cardiomyocyte densities recognize such materials to respond more favorably. Results showed lower wettability (greater hydrophobicity) of CNFs embedded in PLGA compared to pure PLGA, thus providing evidence of selectively lower wettability in aligned CNF regions. Furthermore, the results correlated these changes in hydrophobicity with increased adsorption of fibronectin, laminin, and vitronectin (all proteins known to increase cardiomyocyte adhesion and functions) on CNFs in PLGA compared to pure PLGA, thus providing evidence of selective initial protein adsorption cues on such CNF regions to promote cardiomyocyte adhesion and growth. Lastly, results of the present in vitro study further confirmed increased cardiomyocyte functions by demonstrating greater expression of important cardiomyocyte biomarkers (such as Troponin-T, Connexin-43, and α-sarcomeric actin) when CNFs were aligned compared to randomly oriented in PLGA. In summary, this study provided evidence that cardiomyocyte functions are improved on CNFs aligned in PLGA compared to randomly oriented in PLGA since CNFs are more hydrophobic than PLGA and attract the adsorption of key proteins (fibronectin, laminin, and vironectin) that are known to promote cardiomyocyte adhesion and expression of important cardiomyocyte functions. Thus, future studies should use this knowledge to further design improved CNF:PLGA composites for numerous cardiovascular applications.
Collapse
Affiliation(s)
- Abdullah M Asiri
- Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hadi M Marwani
- Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sher Bahadar Khan
- Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Thomas J Webster
- Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia ; Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| |
Collapse
|
7
|
Abstract
Existing methods for human induced pluripotent stem cell (hiPSC) cardiac differentiation are efficient but require complex, undefined medium constituents that hinder further elucidation of the molecular mechanisms of cardiomyogenesis. Using hiPSCs derived under chemically defined conditions on synthetic matrices, we systematically developed an optimized cardiac differentiation strategy, using a chemically defined medium consisting of just three components: the basal medium RPMI 1640, L-ascorbic acid 2-phosphate and rice-derived recombinant human albumin. Along with small molecule-based induction of differentiation, this protocol produced contractile sheets of up to 95% TNNT2(+) cardiomyocytes at a yield of up to 100 cardiomyocytes for every input pluripotent cell and was effective in 11 hiPSC lines tested. This chemically defined platform for cardiac specification of hiPSCs will allow the elucidation of cardiomyocyte macromolecular and metabolic requirements and will provide a minimal system for the study of maturation and subtype specification.
Collapse
|
8
|
Givvimani S, Pushpakumar S, Veeranki S, Tyagi SC. Dysregulation of Mfn2 and Drp-1 proteins in heart failure. Can J Physiol Pharmacol 2014; 92:583-91. [PMID: 24905188 DOI: 10.1139/cjpp-2014-0060] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Therapeutic approaches for cardiac regenerative mechanisms have been explored over the past decade to target various cardiovascular diseases (CVD). Structural and functional aberrations of mitochondria have been observed in CVD. The significance of mitochondrial maturation and function in cardiomyocytes is distinguished by their attribution to embryonic stem cell differentiation into adult cardiomyocytes. An abnormal fission process has been implicated in heart failure, and treatment with mitochondrial division inhibitor 1 (Mdivi-1), a specific inhibitor of dynamin related protein-1 (Drp-1), has been shown to improve cardiac function. We recently observed that the ratio of mitofusin 2 (Mfn2; a fusion protein) and Drp-1 (a fission protein) was decreased during heart failure, suggesting increased mitophagy. Treatment with Mdivi-1 improved cardiac function by normalizing this ratio. Aberrant mitophagy and enhanced oxidative stress in the mitochondria contribute to abnormal activation of MMP-9, leading to degradation of the important gap junction protein connexin-43 (Cx-43) in the ventricular myocardium. Reduced Cx-43 levels were associated with increased fibrosis and ventricular dysfunction in heart failure. Treatment with Mdivi-1 restored MMP-9 and Cx-43 expression towards normal. In this review, we discuss mitochondrial dynamics, its relation to MMP-9 and Cx-43, and the therapeutic role of fission inhibition in heart failure.
Collapse
Affiliation(s)
- Srikanth Givvimani
- Department of Physiology & Biophysics, School of Medicine, University of Louisville, KY 40202, USA
| | | | | | | |
Collapse
|
9
|
Marchlewska K, Kula K, Walczak-Jedrzejowska R, Kula W, Oszukowska E, Filipiak E, Moszura T, Slowikowska-Hilczer J. Maturational changes in connexin 43 expression in the seminiferous tubules may depend on thyroid hormone action. Arch Med Sci 2013; 9:139-45. [PMID: 23515877 PMCID: PMC3598133 DOI: 10.5114/aoms.2013.33074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 04/12/2011] [Accepted: 05/02/2011] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Connexin 43 (Cx43) mediates the effect of thyroid hormone on Sertoli cell maturation in vitro. We investigated the influence of triiodothyronine (T3) administration on Cx43 expression in relation to the progress in seminiferous tubule maturation. MATERIAL AND METHODS Male rats were daily injected with 100 µg T3/kg body weight from birth until postnatal day (pnd) 5 (transient treatment - tT3) or until pnd 15 (continuous treatment - cT3) or solvent - control (C). On pnd 16 serum hormone levels, body and testes weight, seminiferous tubule morphometry, Cx43 immunostaining and germ cell degeneration were investigated. Cx43 expression was also assessed in six 50-day-old adult untreated rats. RESULT tT3 increased 2.6-fold serum level of T3, testes weight, and seminiferous tubule diameter, and induced maturation-like dislocation of Cx43 expression from the apical to the peripheral region of Sertoli cell cytoplasm. In addition, incidence of Cx43-positive tubules declined from 86% in C to 46% after tT3, being similar to the adult value (30% of tubules Cx43-positive). In turn, cT3 increased serum T3 level 12-fold, and decreased body weight. Seminiferous tubules became shortened and distended, Sertoli cell cytoplasm vacuolated, Cx43 expression had minimal intensity and germ cell degeneration increased. CONCLUSIONS Cx43 might intermediate a short and transient stimulatory effect of T3 on seminiferous tubule maturation that disappeared together with exposure to the toxic effect of a continuously high level of the hormone.
Collapse
Affiliation(s)
| | - Krzysztof Kula
- Department of Andrology, Medical University of Lodz, Poland
| | | | - Wojciech Kula
- Chair of Clinical and Experimental Physiology, Medical University of Lodz, Poland
| | | | - Eliza Filipiak
- Department of Reproductive Endocrinology, Medical University of Lodz, Poland
| | - Tomasz Moszura
- Department of Cardiology, Polish Mother’s Memorial Hospital, Lodz, Poland
| | | |
Collapse
|
10
|
Stout DA, Yoo J, Santiago-Miranda AN, Noemi Santiago-Miranda A, Webster TJ. Mechanisms of greater cardiomyocyte functions on conductive nanoengineered composites for cardiovascular application. Int J Nanomedicine 2012. [PMID: 23180962 PMCID: PMC3501399 DOI: 10.2147/ijn.s34574] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background Recent advances in nanotechnology (materials with at least one dimension between 1 nm and 100 nm) have led to the use of nanomaterials in numerous medical device applications. Recently, nanomaterials have been used to create innovative biomaterials for cardiovascular applications. Specifically, carbon nanofibers (CNF) embedded in poly(lactic-co-glycolic-acid) (PLGA) have been shown to promote cardiomyocyte growth compared with conventional polymer substrates, but the mechanisms involved in such events remain unknown. The aim of this study was to determine the basic mechanism of cell growth on these novel nanocomposites. Methods CNF were added to biodegradable PLGA (50:50 PGA:PLA weight ratio) to increase the conductivity, mechanical and cytocompatibility properties of pure PLGA. For this reason, different PLGA to CNF ratios (100:0, 75:25, 50:50, 25:75, and 0:100 wt%) with different PLGA densities (0.1, 0.05, 0.025, and 0.0125 g/mL) were used, and their compatibility with cardiomyocytes was assessed. Results Throughout all the cytocompatibility experiments, cardiomyocytes were viable and expressed important biomarkers, including cardiac troponin T, connexin-43, and alpha-sarcomeric actin (α-SCA). Adhesion and proliferation experiments indicated that a PLGA density of 0.025 g/mL with a PLGA to CNF ratio of 75:25 and 50:50 (wt%) promoted the best overall cell growth, ie, a 55% increase in cardiomyocyte density after 120 hours compared with pure PLGA and a 75% increase compared with the control at the same time point for 50:50 (wt%). The PLGA:CNF materials were conductive, and their conductivity increased as greater amounts of CNF were added to pure PLGA, from 0 S · m−1 for pure PLGA (100:0 wt%) to 5.5 × 10−3 S · m−1 for pure CNF (0:100 wt%), as compared with natural heart tissue (ranging from 0.16 S · m−1 longitudinally to 0.005 S · m−1 transversely). Tensile tests showed that the addition of CNF increased the tensile strength to mimic that of natural heart tissue, ie, 0.15 MPa for 100% PLGA to 5.41 MPa for the 50:50 (PLGA to CNF [wt%:wt%]) ratio at 0.025 g/mL. Atomic force microscopy indicated that the addition of CNF to PLGA increased the material surface area from 10% (100:0 [PLGA to carbon nanofiber (wt%:wt%)]) to over 60% (50:50 [PLGA to carbon nanofibers (wt%:wt%)]). Lastly, the adsorption of specific proteins (fibronectin and vitronectin) showed significantly more adsorption for the 50:50 PLGA to CNF (wt%:wt%) ratio at 0.025 g/mL PLGA compared with pure PLGA, which may be why cardiomyocyte function increased on CNF-enriched composites. Conclusion This study demonstrates that cardiomyocyte function was enhanced on 50:50 PLGA to CNF (wt%:wt%) composite ratios at 0.025 g/mL PLGA densities because they mimicked native heart tissue tensile strength/conductivity and increased the adsorption of proteins known to promote cardiomyocyte function.
Collapse
Affiliation(s)
- David A Stout
- School of Engineering, Brown University, Providence, RI, USA
| | | | | | | | | |
Collapse
|
11
|
Firestone GL, Kapadia BJ. Minireview: regulation of gap junction dynamics by nuclear hormone receptors and their ligands. Mol Endocrinol 2012; 26:1798-807. [PMID: 22935924 DOI: 10.1210/me.2012-1065] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gap junctions are plasma membrane channels comprising connexin proteins that mediate intercellular permeability and communication. The presence, composition, and function of gap junctions can be regulated by diverse sets of physiological signals. Evidence from many hormone-responsive tissues has shown that connexin expression, modification, stability, and localization can be targeted by nuclear hormone receptors and their ligands through both transcriptional and nontranscriptional mechanisms. The focus of this review is to discuss molecular, cellular, and physiological studies that directly link receptor- and ligand-triggered signaling pathways to the regulation of gap junction dynamics.
Collapse
Affiliation(s)
- Gary L Firestone
- Department of Molecular and Cell Biology, 591 LSA, The University of California at Berkeley, Berkeley, California 94720-3200, USA.
| | | |
Collapse
|
12
|
Jiang XY, Feng XH, Li GY, Zhao Q, Yin HQ. Differential expression of connexin 43 in human autoimmune thyroid disease. Acta Histochem 2010; 112:278-83. [PMID: 19321193 DOI: 10.1016/j.acthis.2009.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/27/2009] [Accepted: 02/02/2009] [Indexed: 11/19/2022]
Abstract
Gap junctions provide a pathway for cell-to-cell communication. Reduced thyroid epithelial cell-cell communication has been reported in some animal models of autoimmune thyroid disease. In order to assess whether this change was similar to human autoimmune thyroid disease, we identified some connexin proteins and their corresponding mRNA in human thyroid gland. The aim of our study was to explore the expression of connexin 43 (Cx43) in the thyroid gland from normal and diseased human thyroid tissue by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). The expression levels of Cx43 in Grave's disease were significantly increased in comparison with those of normal thyroid tissue. There was a significant decrease in expression of Cx43 in Hashimoto's thyroiditis, compared with normal thyroid tissue. These data indicate that changes of Cx43 expression in human autoimmune thyroid disease were associated with variations in thyroid function and hormone secretion.
Collapse
Affiliation(s)
- Xiao-Yan Jiang
- Department of Endocrinology, The First Clinical Hospital of Harbin Medical University, Harbin 150001, China
| | | | | | | | | |
Collapse
|
13
|
Thyroid hormones and cardiac arrhythmias. Vascul Pharmacol 2009; 52:102-12. [PMID: 19850152 DOI: 10.1016/j.vph.2009.10.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/05/2009] [Indexed: 01/09/2023]
Abstract
Thyroid hormone plays an important role in cardiac electrophysiology and Ca2+ handling through both genomic and nongenomic mechanisms of action, while both actions can interfere. Chronic changes in the amount of circulating thyroid hormone due to thyroid dysfunction or systemic disease result in structural, electrophysiological and Ca2+ handling remodeling, while acute changes may affect basal activity of cardiac cells membrane systems. Consequently, long-term or rapid modulation of sarcolemmal ion channels, Ca2+ cycling proteins and intercellular communicating channels by thyroid hormone may affect heart function as well as susceptibility of the heart to arrhythmias. This aspect including pro- and anti-arrhythmic potential of thyroid hormone is highlighted in this review.
Collapse
|
14
|
Almeida NAS, Cordeiro A, Machado DS, Souza LL, Ortiga-Carvalho TM, Campos-de-Carvalho AC, Wondisford FE, Pazos-Moura CC. Connexin40 messenger ribonucleic acid is positively regulated by thyroid hormone (TH) acting in cardiac atria via the TH receptor. Endocrinology 2009; 150:546-54. [PMID: 18787025 DOI: 10.1210/en.2008-0451] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Thyroid hormone (TH) regulates many cardiac genes via nuclear thyroid receptors, and hyperthyroidism is frequently associated with atrial fibrillation. Electrical activity propagation in myocardium depends on the transfer of current at gap junctions, and connexins (Cxs) 40 and 43 are the predominant junction proteins. In mice, Cx40, the main Cx involved in atrial conduction, is restricted to the atria and fibers of the conduction system, which also express Cx43. We studied cardiac expression of Cx40 and Cx43 in conjunction with electrocardiogram studies in mice overexpressing the dominant negative mutant thyroid hormone receptor-beta Delta337T exclusively in cardiomyocytes [myosin heavy chain (MHC-mutant)]. These mice develop the cardiac hypothyroid phenotype in the presence of normal serum TH. Expression was also examined in wild-type mice rendered hypothyroid or hyperthyroid by pharmacological treatment. Atrial Cx40 mRNA and protein levels were decreased (85 and 55%, respectively; P < 0.001) in MHC-mt mice. Atrial and ventricular Cx43 mRNA levels were not significantly changed. Hypothyroid and hyperthyroid animals showed a 25% decrease and 40% increase, respectively, in Cx40 mRNA abundance. However, MHC-mt mice presented very low Cx40 mRNA expression regardless of whether they were made hypothyroid or hyperthyroid. Atrial depolarization velocity, as represented by P wave duration in electrocardiograms of unanesthetized mice, was extremely reduced in MHC-mt mice, and to a lesser extent also in hypothyroid mice (90 and 30% increase in P wave duration). In contrast, this measure was increased in hyperthyroid mice (19% decrease in P wave duration). Therefore, this study reveals for the first time that Cx40 mRNA is up-regulated by TH acting in cardiac atria via the TH receptor and that this may be one of the mechanisms contributing to atrial conduction alterations in thyroid dysfunctions.
Collapse
Affiliation(s)
- Norma A S Almeida
- Laboratório de Endocrinologia Molecular, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Gilleron J, Nebout M, Scarabelli L, Senegas-Balas F, Palmero S, Segretain D, Pointis G. A potential novel mechanism involving connexin 43 gap junction for control of sertoli cell proliferation by thyroid hormones. J Cell Physiol 2006; 209:153-61. [PMID: 16823880 DOI: 10.1002/jcp.20716] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is strong evidence that thyroid hormones through triiodothyronine (T3) regulate Sertoli cell proliferation and differentiation in the neonatal testis. However, the mechanism(s) by which they are able to control Sertoli cell proliferation is unclear. In the present study in vivo approaches (PTU-induced neonatal hypothyroidism known to affect Sertoli cell proliferation) associated with in vitro experiments on a Sertoli cell line were developed to investigate this question. We demonstrated that the inhibitory effect of T3 on Sertoli cell growth, analyzed by evaluating DNA-incorporated [3H] thymidine, was associated with a time and dose-dependent increase in the levels of Cx43, a constitutive protein of gap junctions, known to participate in the control of cell proliferation and the most predominant Cx in the testis. These Cx43 changes were associated with increased gap junction communication measured by gap FRAP. Consistent with these results two specific inhibitors of gap junction coupling, AGA and oleamide, were able to significantly reverse the T3 inhibitory effect on Sertoli cell proliferation. The present data also revealed a nongenomic effect of T3 on Cx43 Sertoli cells that was evidenced by a rapid up-regulation of gap junction plaque number as identified in Cx43-GFP transfected cells exposed to the hormone. This process appears mediated through actin cytoskeleton since incubation of the cells with cytochalasin D totally reversed the T3 stimulatory effect on Cx43-GFP gap junction plaques. Based on these data, we propose a working hypothesis in which Cx43 could be an intermediate target for T3 inhibition of neonatal Sertoli cell proliferation.
Collapse
Affiliation(s)
- Jerome Gilleron
- INSERM U 670, Faculté de Médecine, Université de Paris V René Descartes, Paris, France
| | | | | | | | | | | | | |
Collapse
|
16
|
Xia HJ, Dai DZ, Dai Y. Up-regulated inflammatory factors endothelin, NFκB, TNFα and iNOS involved in exaggerated cardiac arrhythmias in l-thyroxine-induced cardiomyopathy are suppressed by darusentan in rats. Life Sci 2006; 79:1812-9. [PMID: 16822527 DOI: 10.1016/j.lfs.2006.06.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 05/17/2006] [Accepted: 06/09/2006] [Indexed: 11/18/2022]
Abstract
The exaggerated cardiac arrhythmias in cardiomyopathy induced by L-thyroxine treatment are related to ion channelopathies and to an abnormal endothelin (ET) pathway. It was hypothesized that an increased incidence of ventricular fibrillation (VF) could be mediated by inflammatory factors including the ET pathway, nuclear factor kappa B (NFkappaB), tumor necrosis factor-alpha (TNFalpha) and inducible nitric oxide synthase (iNOS). Abnormal expression of NFkappaB, TNFalpha, iNOS and enhanced VF are linked with the activated ET pathway and a significant reversion could be achieved by the selective endothelin A receptor antagonist darusentan. Cardiomyopathy in rats was produced by L-thyroxine treatment (0.3 mg kg(-1) d(-1), sc) for 10 days. The mRNA expression of the ET pathway, NFkappaB, TNFalpha, iNOS and the activity of the redox system were assayed in association with the incidence of VF produced by coronary ligation/reperfusion. Darusentan was administered on days 6-10 of L-thyroxine treatment. The VF incidence, which was higher in the l-thyroxine cardiomyopathy group, was suppressed by darusentan. The mRNA levels of preproET-1, endothelin converting enzyme, endothelin receptor A (ET(A)R), endothelin receptor B (ET(B)R), NFkappaB, TNFalpha and iNOS in left ventricle were up-regulated in the cardiomyopathic heart. There was significant oxidative stress in this cardiomyopathy model. Darusentan suppressed the up-regulated mRNA levels of ET(A)R, ET(B)R, NFkappaB, TNFalpha, and iNOS. These results indicate that the high incidence of VF which is related to up-regulation of inflammatory factors in the cardiomyopathic myocardium is significantly suppressed by selective ET(A)R blockade.
Collapse
Affiliation(s)
- Hui-Jing Xia
- Research Division of Pharmacology, China Pharmaceutical University, Nanjing, China
| | | | | |
Collapse
|
17
|
Salameh A, Dhein S. Pharmacology of gap junctions. New pharmacological targets for treatment of arrhythmia, seizure and cancer? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1719:36-58. [PMID: 16216217 DOI: 10.1016/j.bbamem.2005.09.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 08/25/2005] [Accepted: 09/06/2005] [Indexed: 11/26/2022]
Abstract
Intercellular communication in many organs is maintained via intercellular gap junction channels composed of connexins, a large protein family with a number of isoforms. This gap junction intercellular communication (GJIC) allows the propagation of action potentials (e.g., in brain, heart), and the transfer of small molecules which may regulate cell growth, differentiation and function. The latter has been shown to be involved in cancer growth: reduced GJIC often is associated with increased tumor growth or with de-differentiation processes. Disturbances of GJIC in the heart can cause arrhythmia, while in brain electrical activity during seizures seems to be propagated via gap junction channels. Many diseases or pathophysiological conditions seem to be associated with alterations of gap junction protein expression. Thus, depending on the target disease opening or closure of gap junctions may be of interest, or alteration of connexin expression. GJIC can be affected acutely by changing gap junction conductance or--more chronic--by altering connexin expression and membrane localisation. This review gives an overview on drugs affecting GJIC.
Collapse
Affiliation(s)
- Aida Salameh
- Clinic I for Internal Medicine, Department of Cardiology, University of Leipzig, Johannisallee 32, 04103 Leipzig, Germany.
| | | |
Collapse
|