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Automated patch clamp recordings of action potentials from stem cell derived cardiomyocytes
Abstracts
conclusion, there could be some mechanisms characteristic of drugs which inhibit hERG trafficking. doi:10.1016/j.vascn.2010.11.117
Poster Number: 114 Board Number: 53 Solifenacin induced QTc and hERG channel blockade Maria I. Romana, Jin Zhaib, Ying-Ying Zhoub, Gregory S. Friedrichsb a
Schering Plough, Sparta, NJ, United States Schering Plough Research Institute, Lafayette, NJ, United States
b
Solifenacin is a competitive M3 (1.4 nM), M1 (2.2 nM) and M2 (6.4 nM) muscarinic receptor antagonist that inhibits muscarinic receptors found in the bladder, improving the symptoms of urinary incontinence. Muscarinic receptors are found throughout the body. Frequent side effects of Solifenacin have been identified as expected anticholinergic effects, such as blurred vision or dry mouth. Solifenacin activity on the heart is well tolerated as significant increases in heart rate or blood pressure have not been reported. It was not until recently that a clinical report of QT prolongation and Torsade de Pointes (TdP), a potential fatal polymorphic ventricular arrhythmia, was reported in an elderly woman undergoing Solifenacin treatment (Asajima et al. BJCP, 2008). We tested Solifenacin in conscious telemetered beagle dogs at 1, 3 and 10 mpk. A single oral dose (gavage) study was conducted. Our data show significant prolongation of the PR (8 to 12 msec), QT (23 to 38 msec) and QTc (22 to 30 msec) interval at 10 mg/kg. The mean plasma concentration 6 hrs post-dose was 36.21 ng/ml, which is comparable to the Cmax achieved after the 5 mg/day recommended human dose (Cmax 32.3 ng/ml). No effects were observed follow 3 mpk, exposure achieved at 6 hrs was 4.50 ng/ml. Subsequent voltage clamp studies, using Solifenacin, in L-929 cells transfected with human hERG a subunit, inhibited hERG potassium channel currents in a concentrationdependent manner with an IC50 of 123 nM at room temperature. This represents a 68-fold over the free human Cmax based on 5 mg/day dose. These results suggest that at high Solifenacin doses, blockade of hERG potassium channels may occur and contribute to prolongation of the QT interval with a risk for TdP. doi:10.1016/j.vascn.2010.11.118
Poster Number: 115 Board Number: 54 Automated patch clamp recordings of action potentials from stem cell derived cardiomyocytes Mohamed Kreir, Sonja Stoelzle, Alison Haythornthwaite, Claudia Haarmann, Cecilia Farre, Andrea Brueggemann, David R. Guinot, Michael George, Niels Fertig
e35
derived cardiomyocytes are gaining more interest for safety screening applications since they are considered to represent a more authentic cellular environment compared to using cell lines over-expressing a single ion channel type. Also, since these cells are capable of firing action potentials, investigations of drug effect on the action potentials are possible. In this study, cardiac ion channels and action potentials were recorded from mouse embryonic stem (ES) cell-derived Cor. At cardiomyocytes using a parallel planar patch clamp system recording from up to eight cells simultaneously. Currents from sodium-, potassium-and calcium-channels were identified. In addition, the effect on the action potentials of different compounds were investigated. The data presented show the first parallel recordings of action potentials from an automated patch clamp system and demonstrates the suitability to record ion channels and action potentials for drug screening and safety testing purposes. Data from two different automated patch clamp platforms will be presented. doi:10.1016/j.vascn.2010.11.119
Poster Number: 116 Board Number: 55 Electrophysiological effects of the anti-cancer drug lapatinib on cardiac ion channels Hyang Ae Lee, Sung Ae Hyun, Sung Gurl Park, Ki Suk Kim Korea Institute of Toxicology, KRICT, Daejeon, Republic of Korea Lapatinib is one of several tyrosine kinase inibitors currently undergoing evaluation in clinical trials for use against targeted cancers, such as breast cancer. In the present study patch-clamp techniques for cardiac ion channels were used to determine the effects of lapatinib with respect to the electrophysiological safety of this drug. Lapatinib inhibited the hERG current in a concentrationdependent manner. The half-maximum inhibition concentration (IC50) was 0.82 ± 0.002 μM. In contrast, lapatinib up to 3 μM did not significantly reduce INa, IK1, or ICa amplitudes and inhibited the IKs amplitude only slightly (19.4 ± 4.7%), but still significantly. Previous study showed that when a single 250 mg oral therapeutic dose of lapatinib was administrated, the maximum concentrations (Cmax) and time (Tmax) in plasma were 317 ng/mL (approximately 0.53 μM) and 4 h. This is similar to the IC50 for the hERG current. Based on these experiments, lapatinib has the potential to increase the risk of a life-threatening irregular heart rhythm called QT prolongation. Therefore, all patients taking this drug should be cautiously monitored for clinical signs of long-QT syndrome and severe arrhythmia.
doi:10.1016/j.vascn.2010.11.120
Poster Number: 117 Board Number: 56
Nanion Technologies, Munich, Germany Patch clamp electrophysiology remains the gold-standard for ion channel research. However, the required skills and low throughput make this technique rather unsuitable for screening purposes. Automated planar patch clamp have made the technique accessible to a wider audience and due to the high throughput and high quality data also allow patch clamp based screening earlier in the drug discovery process, for example for early safety profiling of promising drug candidates to prevent late and costly drug drop-outs. Stem cell
Myocardial Ca2+ dysregulation in guinea pig cardiomyocytes and mouse ESC-derived (Cor. At) cells to reveal cardiotoxicity Liang Guo, Jian Yong Qian Hoffmann-La Roche Inc., Nutley, NJ, United States Alteration in intracellular Ca2+ (Ca2+i) regulation has long been implicated in drug-induced cardiomyopathy and arrhythmogenesis. Thus, analysis of myocardial Ca2+i dynamics may be useful in
conclusion, there could be some mechanisms characteristic of drugs which inhibit hERG trafficking. doi:10.1016/j.vascn.2010.11.117
Poster Number: 114 Board Number: 53 Solifenacin induced QTc and hERG channel blockade Maria I. Romana, Jin Zhaib, Ying-Ying Zhoub, Gregory S. Friedrichsb a
Schering Plough, Sparta, NJ, United States Schering Plough Research Institute, Lafayette, NJ, United States
b
Solifenacin is a competitive M3 (1.4 nM), M1 (2.2 nM) and M2 (6.4 nM) muscarinic receptor antagonist that inhibits muscarinic receptors found in the bladder, improving the symptoms of urinary incontinence. Muscarinic receptors are found throughout the body. Frequent side effects of Solifenacin have been identified as expected anticholinergic effects, such as blurred vision or dry mouth. Solifenacin activity on the heart is well tolerated as significant increases in heart rate or blood pressure have not been reported. It was not until recently that a clinical report of QT prolongation and Torsade de Pointes (TdP), a potential fatal polymorphic ventricular arrhythmia, was reported in an elderly woman undergoing Solifenacin treatment (Asajima et al. BJCP, 2008). We tested Solifenacin in conscious telemetered beagle dogs at 1, 3 and 10 mpk. A single oral dose (gavage) study was conducted. Our data show significant prolongation of the PR (8 to 12 msec), QT (23 to 38 msec) and QTc (22 to 30 msec) interval at 10 mg/kg. The mean plasma concentration 6 hrs post-dose was 36.21 ng/ml, which is comparable to the Cmax achieved after the 5 mg/day recommended human dose (Cmax 32.3 ng/ml). No effects were observed follow 3 mpk, exposure achieved at 6 hrs was 4.50 ng/ml. Subsequent voltage clamp studies, using Solifenacin, in L-929 cells transfected with human hERG a subunit, inhibited hERG potassium channel currents in a concentrationdependent manner with an IC50 of 123 nM at room temperature. This represents a 68-fold over the free human Cmax based on 5 mg/day dose. These results suggest that at high Solifenacin doses, blockade of hERG potassium channels may occur and contribute to prolongation of the QT interval with a risk for TdP. doi:10.1016/j.vascn.2010.11.118
Poster Number: 115 Board Number: 54 Automated patch clamp recordings of action potentials from stem cell derived cardiomyocytes Mohamed Kreir, Sonja Stoelzle, Alison Haythornthwaite, Claudia Haarmann, Cecilia Farre, Andrea Brueggemann, David R. Guinot, Michael George, Niels Fertig
e35
derived cardiomyocytes are gaining more interest for safety screening applications since they are considered to represent a more authentic cellular environment compared to using cell lines over-expressing a single ion channel type. Also, since these cells are capable of firing action potentials, investigations of drug effect on the action potentials are possible. In this study, cardiac ion channels and action potentials were recorded from mouse embryonic stem (ES) cell-derived Cor. At cardiomyocytes using a parallel planar patch clamp system recording from up to eight cells simultaneously. Currents from sodium-, potassium-and calcium-channels were identified. In addition, the effect on the action potentials of different compounds were investigated. The data presented show the first parallel recordings of action potentials from an automated patch clamp system and demonstrates the suitability to record ion channels and action potentials for drug screening and safety testing purposes. Data from two different automated patch clamp platforms will be presented. doi:10.1016/j.vascn.2010.11.119
Poster Number: 116 Board Number: 55 Electrophysiological effects of the anti-cancer drug lapatinib on cardiac ion channels Hyang Ae Lee, Sung Ae Hyun, Sung Gurl Park, Ki Suk Kim Korea Institute of Toxicology, KRICT, Daejeon, Republic of Korea Lapatinib is one of several tyrosine kinase inibitors currently undergoing evaluation in clinical trials for use against targeted cancers, such as breast cancer. In the present study patch-clamp techniques for cardiac ion channels were used to determine the effects of lapatinib with respect to the electrophysiological safety of this drug. Lapatinib inhibited the hERG current in a concentrationdependent manner. The half-maximum inhibition concentration (IC50) was 0.82 ± 0.002 μM. In contrast, lapatinib up to 3 μM did not significantly reduce INa, IK1, or ICa amplitudes and inhibited the IKs amplitude only slightly (19.4 ± 4.7%), but still significantly. Previous study showed that when a single 250 mg oral therapeutic dose of lapatinib was administrated, the maximum concentrations (Cmax) and time (Tmax) in plasma were 317 ng/mL (approximately 0.53 μM) and 4 h. This is similar to the IC50 for the hERG current. Based on these experiments, lapatinib has the potential to increase the risk of a life-threatening irregular heart rhythm called QT prolongation. Therefore, all patients taking this drug should be cautiously monitored for clinical signs of long-QT syndrome and severe arrhythmia.
doi:10.1016/j.vascn.2010.11.120
Poster Number: 117 Board Number: 56
Nanion Technologies, Munich, Germany Patch clamp electrophysiology remains the gold-standard for ion channel research. However, the required skills and low throughput make this technique rather unsuitable for screening purposes. Automated planar patch clamp have made the technique accessible to a wider audience and due to the high throughput and high quality data also allow patch clamp based screening earlier in the drug discovery process, for example for early safety profiling of promising drug candidates to prevent late and costly drug drop-outs. Stem cell
Myocardial Ca2+ dysregulation in guinea pig cardiomyocytes and mouse ESC-derived (Cor. At) cells to reveal cardiotoxicity Liang Guo, Jian Yong Qian Hoffmann-La Roche Inc., Nutley, NJ, United States Alteration in intracellular Ca2+ (Ca2+i) regulation has long been implicated in drug-induced cardiomyopathy and arrhythmogenesis. Thus, analysis of myocardial Ca2+i dynamics may be useful in