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Nilsson, Mats F
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Publications (9 of 9) Show all publications
Ritchie, H. E., Svensson, C. H., Nilsson, M. F. & Webster, W. S. (2014). A comparison of drug-induced cardiotoxicity in rat embryos cultured in human serum or protein free media. Journal of pharmacological and toxicological methods, 70(3), 276-282
Open this publication in new window or tab >>A comparison of drug-induced cardiotoxicity in rat embryos cultured in human serum or protein free media
2014 (English)In: Journal of pharmacological and toxicological methods, ISSN 1056-8719, E-ISSN 1873-488X, Vol. 70, no 3, p. 276-282Article in journal (Refereed) Published
Abstract [en]

Introduction: Although much reproductive toxicology research is performed in live animals there is increasing use of in vitro techniques primarily to identify potential hazards with human exposure. As many in vitro studies are undertaken using protein free media, the standard protocol is to compare the effect concentration determined in vitro with the predicted therapeutic free plasma concentration in humans. The aim of the present study was to test this rationale by comparing the effect of a small number of therapeutic drugs on heart rate of rodent embryos cultured in human sera or protein free serum. Methods: Whole rat embryos were cultured in protein-free media or human serum to which drugs (amiodarone, citalopram, dofetilide, haloperidol, paroxetine, quetiapine, or trazodone) known to induce embryonic bradycardia were added. Embryonic heart rate was observed before and after addition of drugs. Results: Most of the tested drugs (5/7) caused a greater decrease in embryonic heart rate in human sera than predicted based on the protein binding of the drug. Discussion: The results suggest that there is less unbound drug in the protein free media and/or more unbound drug in the human sera than predicted. Variables such as saturated protein binding and pH cannot fully explain our results. Since the results did not validate the original rationale, reproductive toxicity results obtained using protein free in vitro techniques may not have the large safety factors predicted on the basis of protein binding. Crown Copyright (C) 2014 Published by Elsevier Inc. All rights reserved.

Keywords
In vitro screens, Teratogenicity, Pharmaceuticals, Methods, Whole rat embryo culture amiodarone, Citalopram, Dofetilide
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:uu:diva-241535 (URN)10.1016/j.vascn.2014.07.008 (DOI)000346091500010 ()
Available from: 2015-01-13 Created: 2015-01-13 Last updated: 2018-01-11Bibliographically approved
Nilsson, M. F. & Webster, W. S. (2014). Effects of Macrolide Antibiotics on Rat Embryonic Heart Function In Vitro. Birth defects research. Part B. Developmental and reproductice toxicology, 101(2), 189-198
Open this publication in new window or tab >>Effects of Macrolide Antibiotics on Rat Embryonic Heart Function In Vitro
2014 (English)In: Birth defects research. Part B. Developmental and reproductice toxicology, ISSN 1542-9733, E-ISSN 1542-9741, Vol. 101, no 2, p. 189-198Article in journal (Refereed) Published
Abstract [en]

The Swedish Medical Product Agency (MPA) has listed erythromycin as a suggested human teratogen, causing cardiovascular malformations. It is further suggested that this may be a class effect of macrolide antibiotics. The proposed teratogenic mechanism is blockade of the human ether-a-go-go-related (hERG)/I-Kr current in the embryonic heart causing bradycardia and arrhythmia resulting in altered cardiac blood flow and/or embryonic hypoxia. To test this hypothesis, we examined the effect of three macrolide antibiotics on the function of the rat embryonic heart. Gestational day 13 rat embryos in vitro were exposed to erythromycin (25-500 mu M), clarithromycin (25-500 mu M), or azithromycin (100 mu M to 1mM) for 3 hr. The effect on the embryonic heart was monitored every hour. The results showed that erythromycin and clarithromycin caused a concentration-dependent bradycardia. Twenty-five micromolar was a no-effect concentration for erythromycin and was close to a no-effect concentration for clarithromycin. Azithromycin only caused significant bradycardia at 1mM. Additional studies were performed with the embryos cultured at 40 degrees C instead of 38 degrees C, to mimic fever. The increased temperature increased the number of arrhythmias but did not worsen the drug-induced bradycardia. The results support the concept that erythromycin and clarithromycin can adversely affect the embryonic heart but only at concentrations well outside expected embryonic exposure in the human

Keywords
embryonic cardiac function, hERG/IKr-blocking drugs, macrolide antibiotics, teratogenicity
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:uu:diva-225070 (URN)10.1002/bdrb.21107 (DOI)000334677000009 ()
Available from: 2014-06-23 Created: 2014-05-27 Last updated: 2018-01-11Bibliographically approved
Webster, W. S., Nilsson, M. & Ritchie, H. (2014). Therapeutic Drugs that Slow the Heart Rate of Early Rat Embryos. Is there a Risk for the Human?. Current pharmaceutical design, 20(34), 5364-5376
Open this publication in new window or tab >>Therapeutic Drugs that Slow the Heart Rate of Early Rat Embryos. Is there a Risk for the Human?
2014 (English)In: Current pharmaceutical design, ISSN 1381-6128, E-ISSN 1873-4286, Vol. 20, no 34, p. 5364-5376Article in journal (Refereed) Published
Abstract [en]

During the organogenic period of development the cardiovascular system of the embryo fulfills several functions including delivery of oxygen and nutrients and a hemodynamic role necessary for cardiac morphogenesis, angiogenesis and hematopoiesis. It is expected that at each stage of embryonic development there is an ideal embryonic heart rate and contractility that maintains the optimal blood flow and pressure to fulfill these various functions. In vitro rat embryo culture studies have revealed that many therapeutic drugs (antiarrhythmics, antidepressants, antipsychotics and anticonvulsants), that may be taken during human pregnancy, cause a concentration-dependent slowing of the embryonic heart and irregular heart rate at higher concentrations. The concentrations causing bradycardia in vitro are often close to human therapeutic plasma concentrations and raise concern that these drugs can potentially cause embryonic death or malformations, and that current reproductive toxicity testing does not adequately examine possible effects of drugs on the embryo's cardiac function.

Keywords
Bradycardia, arrhythmia, antidepressants, hERG, antipsychotics, pregnancy, first trimester, heart, embryo, fetal, rat, human, cardiac, ion channels
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:uu:diva-235212 (URN)10.2174/1381612820666140205151146 (DOI)000342004400002 ()24502593 (PubMedID)
Available from: 2014-10-29 Created: 2014-10-29 Last updated: 2018-01-11Bibliographically approved
Nilsson, M. (2013). Assessment of Drug-Induced Cardiotoxicity during Rat Embryo Development. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Assessment of Drug-Induced Cardiotoxicity during Rat Embryo Development
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The potassium ion channel (hERG/IKr) is important for normal heart function and drug-induced blockade of the channel in adult humans can lead to irregular heart rhythms (arrhythmia).  The ion channel is also essential for early cardiac function in the embryo and therapeutic drugs which block this channel have been shown to cause birth defects in animal studies.  A wide range of birth defects have been seen including cleft lip/palate, distal limb defects and heart malformations.

These malformations are associated with periods of hypoxia and altered blood flow in the embryo associated with the drug-induced heart rhythm disorders and bradycardia. It is also well known that other experimental procedures causing periods of hypoxia in the embryo can give rise to similar defects as those seen with drugs that block the hERG/IKr channel. Paper I on the thesis deals with risk assessment for use in pregnancy of drugs which block hERG/IKr.   Evaluation of the risk of birth defects is largely based on the results of experimental studies on animals. Guidelines for how such standard tests are to be performed were determined by regulatory authorities several decades ago. However, there are examples where safety studies for drugs blocking hERG/IKr, although fulfilling regulatory guidelines, have been carried out at a suboptimal dose range and failed to detect teratogenicity.  A consequence of this is that the teratogenic potential of hERG/IKr blocking drugs have been missed in standard safety testing. The results of the paper I show that the teratogenic properties of the drug astemizole (withdrawn from the market several years ago because of fatal cardiac arrhythmias in adults related to the blockade of hERG/IKr) were missed in the initial safety studies.

Paper II shows that several drugs that block cardiac ion channels other than hERG/IKr can also disrupt fetal cardiac function during embryonic development. However, the concentrations required to cause these changes are much higher than is likely to occur during normal use of the medicines and based on these results that are not considered a risk when taken during pregnancy.

Paper III deals with the possible teratogenicity of erythromycin.  From the Swedish Birth Defects Register there have been signals that use of erythromycin (which has hERG/IKr-blocking properties) during pregnancy is associated with an increased risk of cardiovascular malformations. Paper III shows that the levels of erythromycin needed to disrupt fetal cardiac function during embryonic development are unlikely to occur after normal oral treatment with erythromycin.

Paper IV shows that the embryonic rat heart undergoes major changes in sensitivity to blockade of specific cardiac ion channels during the organogenic period. This is an important observation from the perspective that there may be periods during embryonic development when the embryo is more or less sensitive to the effect of drugs that affect specific ion channels.

To conclude, papers I-IV show that the study of drug effects on the gestation day 13 rat embryonic heart, together with the use of computational assisted image analysis of the cardiac response, provides an in vitro model for hazard identification of compounds with the potential to adversely affect heart function in the developing embryo.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. p. 77
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 177
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:uu:diva-206882 (URN)978-91-554-8745-4 (ISBN)
Public defence
2013-10-18, A1:107a, Biomedicinskt Centrum, Husargatan 3, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2013-09-27 Created: 2013-09-05 Last updated: 2018-01-11
Nilsson, M. F., Skold, A.-C., Ericson, A.-C., Annas, A., Villar, R. P., Cebers, G., . . . Webster, W. S. (2013). Comparative effects of sodium channel blockers in short term rat whole embryo culture. Toxicology and Applied Pharmacology, 272(2), 306-312
Open this publication in new window or tab >>Comparative effects of sodium channel blockers in short term rat whole embryo culture
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2013 (English)In: Toxicology and Applied Pharmacology, ISSN 0041-008X, E-ISSN 1096-0333, Vol. 272, no 2, p. 306-312Article in journal (Refereed) Published
Abstract [en]

This study was undertaken to examine the effect on the rat embryonic heart of two experimental drugs (AZA and AZB) which are known to block the sodium channel Nav1.5, the hERG potassium channel and the L-type calcium channel. The sodium channel blockers bupivacaine, lidocaine, and the L-type calcium channel blocker nifedipine were used as reference substances. The experimental model was the gestational day (GD) 13 rat embryo cultured in vitro. In this model the embryonic heart activity can be directly observed, recorded and analyzed using computer assisted image analysis as it responds to the addition of test drugs. The effect on the heart was studied for a range of concentrations and for a duration up to 3 h. The results showed that AZA and AZB caused a concentration-dependent bradycardia of the embryonic heart and at high concentrations heart block. These effects were reversible on washout. In terms of potency to cause bradycardia the compounds were ranked AZB > bupivacaine > AZA > lidocaine > nifedipine. Comparison with results from previous studies with more specific ion channel blockers suggests that the primary effect of AZA and AZB was sodium channel blockage. The study shows that the short-term rat whole embryo culture (WEC) is a suitable system to detect substances hazardous to the embryonic heart.

Keywords
Embryonic physiology, Cardiac function, Hazard identification, Sodium channel blocker, Drugs during pregnancy
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-211025 (URN)10.1016/j.taap.2013.06.023 (DOI)000325905500006 ()
Available from: 2013-11-20 Created: 2013-11-19 Last updated: 2017-12-06Bibliographically approved
Nilsson, M. F., Helen, R. & Webster, W. S. (2013). The effect on rat embryonic heart rate of Na+-, K+ and Ca2+ channel blockers, and the human teratogen phenytoin, changes with gestational age. Birth defects research. Part B. Developmental and reproductice toxicology, 98(5), 416-427
Open this publication in new window or tab >>The effect on rat embryonic heart rate of Na+-, K+ and Ca2+ channel blockers, and the human teratogen phenytoin, changes with gestational age
2013 (English)In: Birth defects research. Part B. Developmental and reproductice toxicology, ISSN 1542-9733, E-ISSN 1542-9741, Vol. 98, no 5, p. 416-427Article in journal (Refereed) Published
Abstract [en]

To determine the changes in dependence on ion channels during rat cardiac development we compared the effects of four ion channel blockers on rat embryonic heart function during the organogenic period from gestational day (GD) 10-15. Rat embryos in culture were exposed to either the hERG potassium channel blocker dofetilide (400 nM), the sodium channel blocker lidocaine (250 μM) the L-type calcium channel blocker nifedipine (1.8 μM), or the multi-channel blocker phenytoin (200 μM). Lidocaine slowed the heart rate (HR) with the effect becoming more severe with increasing GD. Dofetilide slowed the embryonic HR and caused arrhythmias with the most severe effect on GD 11-13. Nifedipine primarily caused a negative inotropic effect except on GD 10 when it stopped the heart in most embryos. Phenytoin stopped the heart of most GD 10-12 embryos while on GD 13-15 phenytoin it slowed the heart. The results demonstrate that as the rat heart develops during the organogenic period its functional dependence on ion channels changes markedly. These changes are important for understanding drug effects on the embryo during pregnancy and the methodology used provides a simple procedure for assessing drug effects on the developing heart.

National Category
Pharmacology and Toxicology
Research subject
Behavioural Neuroscience; Toxicology
Identifiers
urn:nbn:se:uu:diva-206881 (URN)10.1002/bdrb.21084 (DOI)000328470100005 ()
Available from: 2013-09-05 Created: 2013-09-05 Last updated: 2018-01-11Bibliographically approved
Niazi, M. K., Ibrahim, M. T., Nilsson, M. F., Sköld, A.-C., Guan, L. & Nyström, I. (2011). Robust Signal Generation and Analysis of Rat Embryonic Heart Rate In Vitro using Laplacian Eigenmaps and Empirical Mode Decomposition. In: Computer analysis of images and patterns: 14th International Conference, CAIP 2011, pt 2. Paper presented at 14th International Conference on Computer Analysis of Images and Patterns (CAIP) AUG 29-31, 2011 Seville, SPAIN (pp. 523-530). Springer-Verlag
Open this publication in new window or tab >>Robust Signal Generation and Analysis of Rat Embryonic Heart Rate In Vitro using Laplacian Eigenmaps and Empirical Mode Decomposition
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2011 (English)In: Computer analysis of images and patterns: 14th International Conference, CAIP 2011, pt 2, Springer-Verlag , 2011, p. 523-530Conference paper, Published paper (Refereed)
Abstract [en]

To develop an accurate and suitable method for measuring the embryonic heart rate in vitro, a system combining Laplacian eigenmaps and empirical mode decomposition has been proposed. The proposed method assess the heart activity in two steps; signal generation and heart signal analysis. Signal generation is achieved by Laplacian eigenmaps (LEM) in conjunction with correlation co-efficient, while the signal analysis of the heart motion has been performed by the modified empirical mode decomposition (EMD). LEM helps to find the template for the atrium and the ventricle respectively, whereas EMD helps to find the non-linear trend term without defining any regression model. The proposed method also removes the motion artifacts produced due to the the non-rigid deformation in the shape of the embryo, the noise induced during the data acquisition, and the higher order harmonics. To check the authenticity of the proposed method, 151 videos have been investigated. Experimental results demonstrate the superiority of the proposed method in comparison to three recent methods.

Place, publisher, year, edition, pages
Springer-Verlag, 2011
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 6855
National Category
Computer Vision and Robotics (Autonomous Systems)
Identifiers
urn:nbn:se:uu:diva-155123 (URN)000300567300062 ()978-3-642-23677-8 (ISBN)
Conference
14th International Conference on Computer Analysis of Images and Patterns (CAIP) AUG 29-31, 2011 Seville, SPAIN
Available from: 2011-06-16 Created: 2011-06-16 Last updated: 2018-01-12Bibliographically approved
Abela, D., Ritchie, H., Ababneh, D., Gavin, C., Nilsson, M. F., Niazi, M. K., . . . Webster, W. (2010). The effect of drugs with ion channel-blocking activity on the early embryonic rat heart. Birth defects research. Part B. Developmental and reproductice toxicology, 89(5), 429-440
Open this publication in new window or tab >>The effect of drugs with ion channel-blocking activity on the early embryonic rat heart
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2010 (English)In: Birth defects research. Part B. Developmental and reproductice toxicology, ISSN 1542-9733, E-ISSN 1542-9741, Vol. 89, no 5, p. 429-440Article in journal (Refereed) Published
Abstract [en]

This study investigated the effects of a range of pharmaceutical drugs with ion channel-blocking activity on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the blockade of the IKr/hERG channel, that is highly important for the normal functioning of the embryonic rat heart, would cause bradycardia and arrhythmia. Concomitant blockade of other channels was expected to modify the effects of hERG blockade. Fourteen drugs with varying degrees of specificity and affinity toward potassium, sodium, and calcium channels were tested over a range of concentrations. The rat embryos were maintained for 2 hr in culture, 1 hr to acclimatize, and 1 hr to test the effect of the drug. All the drugs caused a concentration-dependent bradycardia except nifedipine, which primarily caused a negative inotropic effect eventually stopping the heart. A number of drugs induced arrhythmias and these appeared to be related to either sodium channel blockade, which resulted in a double atrial beat for each ventricular beat, or IKr/hERG blockade, which caused irregular atrial and ventricular beats. However, it is difficult to make a precise prediction of the effect of a drug on the embryonic heart just by looking at the polypharmacological action on ion channels. The results indicate that the use of the tested drugs during pregnancy could potentially damage the embryo by causing periods of hypoxia. In general, the effects on the embryonic heart were only seen at concentrations greater than those likely to occur with normal therapeutic dosing.

Keywords
embryo/fetal physiology, in vitro screens, mechanisms of teratogenesis, pharmaceuticals
National Category
Computer Vision and Robotics (Autonomous Systems) Pharmaceutical Sciences
Research subject
Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-141481 (URN)10.1002/bdrb.20270 (DOI)000283911500008 ()20973055 (PubMedID)
Available from: 2011-01-12 Created: 2011-01-12 Last updated: 2018-01-12Bibliographically approved
Nilsson, M. F. & Webster, W. S. Comparative effects of erythromycin and clarithromycin on rat embryonic heart function in vitro.
Open this publication in new window or tab >>Comparative effects of erythromycin and clarithromycin on rat embryonic heart function in vitro
(English)Article in journal (Refereed) Submitted
National Category
Pharmacology and Toxicology
Research subject
Toxicology
Identifiers
urn:nbn:se:uu:diva-206880 (URN)
Available from: 2013-09-05 Created: 2013-09-05 Last updated: 2018-01-11Bibliographically approved
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