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Zünkler BJ, Wos-Maganga M, Bohnet S, Kleinau A, Manns D, Chatterjee S. Intracellular Binding of Terfenadine Competes with Its Access to Pancreatic ß-cell ATP-Sensitive K + Channels and Human ether-à-go-go-Related Gene Channels. J Membr Biol 2023; 256:63-77. [PMID: 35763054 PMCID: PMC9884252 DOI: 10.1007/s00232-022-00252-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/02/2022] [Indexed: 02/07/2023]
Abstract
Most blockers of both hERG (human ether-à-go-go-related gene) channels and pancreatic ß-cell ATP-sensitive K+ (KATP) channels access their binding sites from the cytoplasmic side of the plasma membrane. It is unknown whether binding to intracellular components competes with binding of these substances to K+ channels. The whole-cell configuration of the patch-clamp technique, a laser-scanning confocal microscope, and fluorescence correlation spectroscopy (FCS) were used to study hERG channels expressed in HEK (human embryonic kidney) 293 cells and KATP channels from the clonal insulinoma cell line RINm5F. When applied via the pipette solution in the whole-cell configuration, terfenadine blocked both hERG and KATP currents with much lower potency than after application via the bath solution, which was not due to P-glycoprotein-mediated efflux of terfenadine. Such a difference was not observed with dofetilide and tolbutamide. 37-68% of hERG/EGFP (enhanced green-fluorescent protein) fusion proteins expressed in HEK 293 cells were slowly diffusible as determined by laser-scanning microscopy in the whole-cell configuration and by FCS in intact cells. Bath application of a green-fluorescent sulphonylurea derivative (Bodipy-glibenclamide) induced a diffuse fluorescence in the cytosol of RINm5F cells under whole-cell patch-clamp conditions. These observations demonstrate the presence of intracellular binding sites for hERG and KATP channel blockers not dialyzable by the patch-pipette solution. Intracellular binding of terfenadine was not influenced by a mutated hERG (Y652A) channel. In conclusion, substances with high lipophilicity are not freely diffusible inside the cell but steep concentration gradients might exist within the cell and in the sub-membrane space.
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Affiliation(s)
- Bernd J Zünkler
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany.
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany.
| | - Maria Wos-Maganga
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Stefanie Bohnet
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Anne Kleinau
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Detlef Manns
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Shivani Chatterjee
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
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Brennan S, Esposito S, Abdelaziz MIM, Martin CA, Makwana S, Sims MW, Squire IB, Sharma P, Chadwick AE, Rainbow RD. Selective protein kinase C inhibition switches time-dependent glucose cardiotoxicity to cardioprotection. Front Cardiovasc Med 2022; 9:997013. [PMID: 36158799 PMCID: PMC9489859 DOI: 10.3389/fcvm.2022.997013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/15/2022] [Indexed: 12/03/2022] Open
Abstract
Hyperglycaemia at the time of myocardial infarction has an adverse effect on prognosis irrespective of a prior diagnosis of diabetes, suggesting glucose is the damaging factor. In ex vivo models of ischaemia, we demonstrated that deleterious effects of acutely elevated glucose are PKCα/β-dependent, and providing PKCα/β are inhibited, elevated glucose confers cardioprotection. Short pre-treatments with high glucose were used to investigate time-dependent glucose cardiotoxicity, with PKCα/β inhibition investigated as a potential mechanism to reverse the toxicity. Freshly isolated non-diabetic rat cardiomyocytes were exposed to elevated glucose to investigate the time-dependence toxic effects. High glucose challenge for >7.5 min was cardiotoxic, proarrhythmic and lead to contractile failure, whilst cardiomyocytes exposed to metabolic inhibition following 5-min high glucose, displayed a time-dependent protection lasting ∼15 min. This protection was further enhanced with PKCα/β inhibition. Cardioprotection was measured as a delay in contractile failure and KATP channel activation, improved contractile and Ca2+ transient recovery and increased cell survival. Finally, the effects of pre-ischaemic treatment with high glucose in a whole-heart coronary ligation protocol, where protection was evident with PKCα/β inhibition. Selective PKCα/β inhibition enhances protection suggesting glycaemic control with PKC inhibition as a potential cardioprotective therapeutics in myocardial infarction and elective cardiac surgery.
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Affiliation(s)
- Sean Brennan
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Sean Brennan,
| | - Simona Esposito
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Muhammad I. M. Abdelaziz
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Christopher A. Martin
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Samir Makwana
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Mark W. Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
| | - Iain B. Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom
- Leicester NIHR Biomedical Research Centre, Glenfield General Hospital, Leicester, United Kingdom
| | - Parveen Sharma
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Amy E. Chadwick
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, Liverpool, United Kingdom
| | - Richard D. Rainbow
- Department of Cardiovascular, Metabolic Medicine and Liverpool Centre for Cardiovascular Sciences, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- Richard D. Rainbow,
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Effect of hyperglycaemia in combination with moxifloxacin on cardiac repolarization in male and female patients with type I diabetes. Clin Res Cardiol 2022; 111:1147-1160. [PMID: 35596784 PMCID: PMC9525410 DOI: 10.1007/s00392-022-02037-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022]
Abstract
Background Patients with Type 1 diabetes mellitus have been shown to be at a two to ten-fold higher risk of sudden cardiac death (SCD) (Svane et al., Curr Cardiol 2020; 22:112) than the general population, but the underlying mechanism is unclear. Hyperglycaemia is a recognised cause of QTc prolongation; a state patients with type 1 diabetes are more prone to, potentially increasing their risk of ventricular arrhythmia. Understanding the QTc prolongation effect of both hyperglycaemia and the concomitant additive risk of commonly prescribed QTc-prolonging drugs such as Moxifloxacin may help to elucidate the mechanism of sudden cardiac death in this cohort. This single-blinded, placebo-controlled study investigated the extent to which hyperglycaemia prolongs the QTc in controlled conditions, and the potential additive risk of QTc-prolonging medications. Methods 21 patients with type 1 diabetes mellitus were enrolled to a placebo-controlled crossover study at a single clinical trials unit. Patients underwent thorough QTc assessment throughout the study. A ‘hyperglycaemic clamp’ of oral and intravenous glucose was administered with a target blood glucose of > 25 mM and maintained for 2 h on day 1 and day 3, alongside placebo on day 1 and moxifloxacin on day 3. Day 2 served as a control day between the two active treatment days. Thorough QTc assessment was conducted at matched time points over 3 days, and regular blood sampling was undertaken at matched time intervals for glucose levels and moxifloxacin exposure. Results Concentration-effect modelling showed that acute hyperglycaemia prolonged the QTc interval in female and male volunteers with type 1 diabetes by a peak mean increase of 13 ms at 2 h. Peak mean QTc intervals after the administration of intravenous Moxifloxacin during the hyperglycaemic state were increased by a further 9 ms at 2 h, to 22 ms across the entire study population. Regression analysis suggested this additional increase was additive, not exponential. Hyperglycaemia was associated with a significantly greater mean QTc-prolonging effect in females, but the mean peak increase with the addition of moxifloxacin was the same for males and females. This apparent sex difference was likely due to the exclusive use of basal insulin in the male patients, which provided a low level of exogenous insulin during the study assessments thereby mitigating the effects of hyperglycaemia on QTc. This effect was partially overcome by Moxifloxacin administration, suggesting both hyperglycaemia and moxifloxacin prolong QTc by different mechanisms, based on subinterval analysis. Conclusions Hyperglycaemia was found to be a significant cause of QTc prolongation and the additional effect of a QTc-prolonging positive control (moxifloxacin) was found to be additive. Given the high risk of sudden cardiac death in type 1 diabetes mellitus, extra caution should be exercised when prescribing any medication in this cohort for QTc effects, and further research needs to be undertaken to elucidate the exact mechanism underlying this finding and explore the potential prescribing risk in diabetes. Trial Registration NCT number: NCT01984827. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s00392-022-02037-8.
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Yoshimatsu Y, Ishizaka T, Chiba K, Mori K. Usefulness of simultaneous and sequential monitoring of glucose level and electrocardiogram in monkeys treated with gatifloxacin under conscious and nonrestricted conditions. Exp Anim 2018; 67:281-290. [PMID: 29311442 PMCID: PMC5955759 DOI: 10.1538/expanim.17-0136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Drug-induced cardiac electrophysiological abnormalities accompanied by hypoglycemia or
hyperglycemia increase the risk for life-threatening arrhythmia. To assess the
drug-induced cardiotoxic potential associated with extraordinary blood glucose (GLU)
levels, the effect of gatifloxacin (GFLX) which was frequently associated with GLU
abnormality and QT/QTc prolongations in the clinic on blood GLU and electrocardiogram
(ECG) parameters was investigated in cynomolgus monkeys (n=4) given GFLX orally in an
ascending dose regimen (10, 30, 60 and 100 mg/kg). Simultaneous and sequential GLU and ECG
monitoring with a continuous GLU monitoring system and Holter ECG, respectively, were
conducted for 24 h under free-moving conditions. Consequently, GFLX at 30 and 60 mg/kg
dose-dependently induced a transient decrease in GLU without any ECG abnormality 2–4 h
postdose. Highest dose of 100 mg/kg caused severe hypoglycemia with a mean GLU of <30
mg/dL, accompanied by remarkable QT/QTc prolongations by 20–30% in all animals. In
contrast, hyperglycemia without QT/QTc prolongations was noted 24 h after dosing in one
animal. A close correlation between GLU and QTc values was observed in animals treated
with 100 mg/kg, suggesting that GFLX-induced hypoglycemia enhanced QT/QTc prolongations.
Furthermore, the 24-h sequential GLU monitoring data clearly distinguished between
GFLX-induced GLU abnormality and physiological GLU changes influenced by feeding
throughout the day. In conclusion, the combined assessment of continuous GLU and ECG
monitoring is valuable in predicting the drug-induced cardio-electrophysiological risk
associated with both GLU and ECG abnormalities.
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Affiliation(s)
- Yu Yoshimatsu
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Tomomichi Ishizaka
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Katsuyoshi Chiba
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Kazuhiko Mori
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
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Kimura S, Nakao S, Kitaura A, Iwamoto T, Houri K, Matsushima M, Hamasaki S. Sevoflurane causes greater QTc interval prolongation in chronically hyperglycemic patients than in normoglycemic patients. PLoS One 2017; 12:e0188555. [PMID: 29194447 PMCID: PMC5711029 DOI: 10.1371/journal.pone.0188555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/13/2017] [Indexed: 11/30/2022] Open
Abstract
QTc interval prolongation is a serious diabetic complication and increases mortality rate. Hyperglycemia inhibits the rapid component of delayed rectifier potassium channel currents (Ikr) and prolongs the QTc interval on electrocardiograms. Sevoflurane also inhibits the Ikr and causes QTc interval prolongation. In fact, torsade de pointes occurred in a patient with poorly controlled diabetes mellitus during sevoflurane anesthesia. We enrolled 74 patients, including 37 normoglycemic patients (glycated hemoglobin [HbA1c]: <6.5%) (NG group) and 37 chronically hyperglycemic patients (HbA1c: ≥6.5%) (HG group). Anesthesia was induced with 2 mg/kg propofol and 0.3 μg/kg/min remifentanil, and maintained with 2% sevoflurane in 40% O2 and 0.2-0.3 μg/kg/min remifentanil. The QT interval and Tp-e interval (from the peak to the end of the T wave) were measured before and at 5, 10, 30, 60, 90, and 120 min after the administration of sevoflurane and adjusted for the patient's heart rate (QTc and Tp-ec, respectively). P-values of <0.05 were considered statistically significant. The QTc and the Tp-ec intervals of the two groups did not differ significantly before the administration of sevoflurane. The QTc interval gradually increased with time in both groups and was significantly longer than the baseline value at 10 min after the administration of sevoflurane in both groups. The QTc interval of the HG group was significantly longer than that of the NG group at 90 min and 120 min after the administration of sevoflurane. The Tp-ec interval was not affected by sevoflurane in either group.We have demonstrated that sevoflurane significantly prolongs the QTc interval, and that the extent of the prolongation is significantly greater in chronically hyperglycemic patients than in normoglycemic patients. Although Tp-ec is not affected by sevoflurane, it should be noted that the simultaneous blockade of potassium channels would increase the risk of arrhythmias.
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Affiliation(s)
- Seishi Kimura
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Shinichi Nakao
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Atsuhiro Kitaura
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Tatushige Iwamoto
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Kei Houri
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Mayuka Matsushima
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
| | - Shinichi Hamasaki
- Department of Anesthesiology, Kindai University Faculty of Medicine, OsakaSayama, Osaka, Japan
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Inter-individual variability and modeling of electrical activity: a possible new approach to explore cardiac safety? Sci Rep 2016; 6:37948. [PMID: 27901061 PMCID: PMC5128803 DOI: 10.1038/srep37948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/02/2016] [Indexed: 11/08/2022] Open
Abstract
Safety pharmacology aims to predict rare side effects of new drugs. We explored whether rare pro-arrhythmic effects could be linked to the variability of the effects of these drugs on ion currents and whether taking into consideration this variability in computational models could help to better detect and predict cardiac side effects. For this purpose, we evaluated how intra- and inter-individual variability influences the effect of hERG inhibition on both the action potential duration and the occurrence of arrhythmias. Using two computer simulation models of human action potentials (endocardial and Purkinje cells), we analyzed the contribution of two biological parameters on the pro-arrhythmic effects of several hERG channel blockers: (i) spermine concentration, which varies with metabolic status, and (ii) L-type calcium conductance, which varies due to single nucleotide polymorphisms or mutations. By varying these parameters, we were able to induce arrhythmias in 1 out of 16 simulations although conventional modeling methods to detect pro-arrhythmic molecules failed. On the basis of our results, taking into consideration only 2 parameters subjected to intra- and inter-individual variability, we propose that in silico computer modeling may help to better define the risks of new drug candidates at early stages of pre-clinical development.
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Secondary pharmacology: screening and interpretation of off-target activities – focus on translation. Drug Discov Today 2016; 21:1232-42. [DOI: 10.1016/j.drudis.2016.04.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/22/2016] [Accepted: 04/22/2016] [Indexed: 12/19/2022]
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Jackson R, Brennan S, Fielding P, Sims MW, Challiss RAJ, Adlam D, Squire IB, Rainbow RD. Distinct and complementary roles for α and β isoenzymes of PKC in mediating vasoconstrictor responses to acutely elevated glucose. Br J Pharmacol 2016; 173:870-87. [PMID: 26660275 DOI: 10.1111/bph.13399] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/23/2015] [Accepted: 11/30/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE We investigated the hypothesis that elevated glucose increases contractile responses in vascular smooth muscle and that this enhanced constriction occurs due to the glucose-induced PKC-dependent inhibition of voltage-gated potassium channels. EXPERIMENTAL APPROACH Patch-clamp electrophysiology in rat isolated mesenteric arterial myocytes was performed to investigate the glucose-induced inhibition of voltage-gated potassium (Kv ) current. To determine the effects of glucose in whole vessel, wire myography was performed in rat mesenteric, porcine coronary and human internal mammary arteries. KEY RESULTS Glucose-induced inhibition of Kv was PKC-dependent and could be pharmacologically dissected using PKC isoenzyme-specific inhibitors to reveal a PKCβ-dependent component of Kv inhibition dominating between 0 and 10 mM glucose with an additional PKCα-dependent component becoming evident at concentrations greater than 10 mM. These findings were supported using wire myography in all artery types used, where contractile responses to vessel depolarization and vasoconstrictors were enhanced by increasing bathing glucose concentration, again with evidence for distinct and complementary PKCα/PKCβ-mediated components. CONCLUSIONS AND IMPLICATIONS Our results provide compelling evidence that glucose-induced PKCα/PKCβ-mediated inhibition of Kv current in vascular smooth muscle causes an enhanced constrictor response. Inhibition of Kv current causes a significant depolarization of vascular myocytes leading to marked vasoconstriction. The PKC dependence of this enhanced constrictor response may present a potential therapeutic target for improving microvascular perfusion following percutaneous coronary intervention after myocardial infarction in hyperglycaemic patients.
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Affiliation(s)
- Robert Jackson
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Peter Fielding
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Mark W Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - R A John Challiss
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - David Adlam
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Iain B Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Richard D Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
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Abstract
BACKGROUND The QT interval on an electrocardiogram represents ventricular repolarization time. Increased length of this interval, known as corrected QT (QTc) prolongation, can be a precursor to torsade de pointes, a potentially life-threatening ventricular dysrhythmia. An association exists between blood glucose and QTc interval in ambulatory populations. Because both hyperglycemia and QTc prolongation are common in critically ill patients, we sought to examine the relationship between blood glucose, QTc interval prolongation, and all-cause mortality in critically ill patients. METHODS We studied adult patients admitted to cardiac monitoring units. Blood glucose and other clinical variables were abstracted from the medical record. Corrected QT measurements were automatically derived from continuous bedside cardiac monitoring systems. RESULTS Twenty-five percent (233/940) of the patients had QTc prolongation, and 53% had elevated blood glucose (>140 mg/dL) during hospitalization. Adjusted odds for QTc prolongation were 2.1 (95% confidence interval, 1.5-3.1) for moderately elevated blood glucose (140-180 mg/dL) and 3.7 (95% confidence interval, 2.5-5.4) for severely elevated blood glucose (>180 mg/dL). Mortality rate was highest (16%) in patients experiencing both severely elevated blood glucose (>180 mg/dL) and QTc interval prolongation. CONCLUSIONS Hyperglycemia is linked with QTc prolongation, and both are associated with increased odds of mortality in critically ill patients. Further studies are needed to extrapolate the relationship between glucose and ventricular repolarization, as well as appropriate glucose control parameters and QTc interval monitoring in critical care units.
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Tatsuishi W, Adachi H, Murata M, Tomono J, Okonogi S, Okada S, Hasegawa Y, Ezure M, Kaneko T, Ohshima S. Postoperative hyperglycemia and atrial fibrillation after coronary artery bypass graft surgery. Circ J 2014; 79:112-8. [PMID: 25392072 DOI: 10.1253/circj.cj-14-0989] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Postoperative atrial fibrillation (AF) is a common complication following coronary artery bypass grafting (CABG). We investigated the risk factors for postoperative AF and analyzed the relationship between blood sugar concentration (BS) and AF after CABG. METHODS AND RESULTS A total of 199 consecutive patients who underwent isolated CABG were retrospectively examined and classified according to the presence (n=95) or absence (n=104) of postoperative AF. On univariate analysis mean postoperative BS (P<0.001), postoperative drainage volume (P<0.001), age (P=0.034), presence of diabetes mellitus (DM; P=0.004), and postoperative estimated glomerular filtration rate (P=0.032) were significant risk factors for postoperative AF. On multivariate analysis mean postoperative BS (OR, 1.041; 95% CI: 1.008-1.079; P<0.001), postoperative drainage volume (OR, 1.003; 95% CI: 1.001-1.006; P=0.001), and age (OR, 1.040; 95% CI: 1.002-1.083; P=0.041) were significant risk factors for postoperative AF. Postoperative AF often occurred in patients with high postoperative BS, irrespective of DM. The BS cut-off that predicted postoperative AF occurrence was 180 mg/dl. A strong positive correlation existed between the time of the maximum postoperative BS and AF onset time (ρ=0.746). CONCLUSIONS Mean postoperative BS and postoperative drainage volume are risk factors for AF after CABG. AF was strongly associated with maximum postoperative BS. Intensive glycemic control could reduce AF occurrence after CABG.
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Affiliation(s)
- Wataru Tatsuishi
- Department of Cardiovascular Surgery, Tokyo Women's Medical University, Medical Center East, Tokyo; Department of Cardiovascular Surgery, Gunma Prefectural Cardiovascular Center, Maebashi, Japan.
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Sims MW, Winter J, Brennan S, Norman RI, André Ng G, Squire IB, Rainbow RD. PKC-mediated toxicity of elevated glucose concentration on cardiomyocyte function. Am J Physiol Heart Circ Physiol 2014; 307:H587-97. [DOI: 10.1152/ajpheart.00894.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
While it is well established that mortality risk after myocardial infarction (MI) increases in proportion to blood glucose concentration at the time of admission, it is unclear whether there is a direct, causal relationship. We investigated potential mechanisms by which increased blood glucose may exert cardiotoxicity. Using a Wistar rat or guinea-pig isolated cardiomyocyte model, we investigated the effects on cardiomyocyte function and electrical stability of alterations in extracellular glucose concentration. Contractile function studies using electric field stimulation (EFS), patch-clamp recording, and Ca2+ imaging were used to determine the effects of increased extracellular glucose concentration on cardiomyocyte function. Increasing glucose from 5 to 20 mM caused prolongation of the action potential and increased both basal Ca2+ and variability of the Ca2+ transient amplitude. Elevated extracellular glucose concentration also attenuated the protection afforded by ischemic preconditioning (IPC), as assessed using a simulated ischemia and reperfusion model. Inhibition of PKCα and β, using Gö6976 or specific inhibitor peptides, attenuated the detrimental effects of glucose and restored the cardioprotected phenotype to IPC cells. Increased glucose concentration did not attenuate the cardioprotective role of PKCε, but rather activation of PKCα and β masked its beneficial effect. Elevated extracellular glucose concentration exerts acute cardiotoxicity mediated via PKCα and β. Inhibition of these PKC isoenzymes abolishes the cardiotoxic effects and restores IPC-mediated cardioprotection. These data support a direct link between hyperglycemia and adverse outcome after MI. Cardiac-specific PKCα and β inhibition may be of clinical benefit in this setting.
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Affiliation(s)
- Mark W. Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - James Winter
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Robert I. Norman
- Department of Medical and Social Care Education, University of Leicester, Leicester, United Kingdom
| | - G. André Ng
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Iain B. Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
| | - Richard D. Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, United Kingdom; and
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Caillier B, Pilote S, Patoine D, Levac X, Couture C, Daleau P, Simard C, Drolet B. Metabolic syndrome potentiates the cardiac action potential-prolonging action of drugs: A possible ‘anti-proarrhythmic’ role for amlodipine. Pharmacol Res 2012; 65:320-7. [DOI: 10.1016/j.phrs.2011.11.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 11/21/2011] [Accepted: 11/22/2011] [Indexed: 12/14/2022]
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