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Ritchie HE, Polson JW, Xia A, Webster W. Effect of vinpocetine on embryonic heart rate in vitro. Curr Res Toxicol 2023; 5:100125. [PMID: 37753450 PMCID: PMC10518341 DOI: 10.1016/j.crtox.2023.100125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/11/2023] [Accepted: 09/14/2023] [Indexed: 09/28/2023] Open
Abstract
Vinpocetine is a readily available nutritional supplement claimed to improve memory and weight loss. However, it blocks the Ikr current essential for cardiac action potential repolarisation and Ikr inhibition can cause "torsade de pointes" arrhythmias and sudden death. Moreover, Ikr blockers have exhibited teratogenic effects in reproductive toxicology studies, leading to increased birth defects and embryonic mortality. The FDA advises against vinpocetine use in pregnant and prospective mothers based on animal studies showing dose-dependent fetal mortality in rats and rabbits, and cardiovascular malformations in surviving fetuses. However, the mechanisms responsible for vinpocetine's fetal toxicity remain unclear. The present study used rat embryo culture to evaluate vinpocetine and its major metabolite, apovincaminic acid, on embryonic heart rate, a possible causative factor behind its adverse effects. Both compounds induced embryonic bradycardia in a concentration-dependent manner, with vinpocetine proving more potent. The minimum vinpocentine concentration to induce bradycardia was 100 nM, a level unlikely to be reached in humans following typical doses. Embryonic arrhythmias were also observed at the highest concentrations. These results suggest that the FDA's cautionary statement may generate undue anxiety, although re-evaluation of teratogenicity risk associated with vinpocetine should be revisited if a link to cardiac arrhythmias in adults is established.
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Affiliation(s)
- Helen Elizabeth Ritchie
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, Australia
| | - Jaimie W. Polson
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, Australia
| | - Andrea Xia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, Australia
| | - William Webster
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, Australia
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Ritchie HE, Abela D, Ababneh D, Howe AM, Farrell E, Hegedus E. The effect of phenytoin on embryonic heart rate in Vivo. Reprod Toxicol 2021; 106:109-114. [PMID: 34653594 DOI: 10.1016/j.reprotox.2021.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/07/2021] [Accepted: 10/09/2021] [Indexed: 10/20/2022]
Abstract
Phenytoin is a known human teratogen with unknown etiology. Several mechanisms have been proposed including disturbances in folate metabolism, induction of embryonic hypoxia following phenytoin-induced bradycardia, free radical formation following re-oxygenation and phenytoin-induced maternal hyperglycemia. Using high frequency ultrasound, we demonstrated that phenytoin induced a dramatic decrease in the heart rate of embryos. This coincided with a moderate transient decrease in maternal heart rate and blood glucose levels. Embryonic heart rate had not fully recovered 24 h later in some embryos despite normal maternal physiological parameters. In a separate study, extent of hypoxia was measured using the marker pimonidazole. Phenytoin-exposed embryos did not demonstrate increased hypoxia compared to control embryos at 2, 4, 8 or 24 h dosing. Together our results show that phenytoin induces malformations as a result of a combination of insults: embryonic bradycardia, maternal bradycardia and maternal hyperglycemia. However, this does not appear to result in measurable embryonic hypoxia in our animal model.
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Affiliation(s)
- Helen E Ritchie
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia.
| | - Dominqiue Abela
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Deena Ababneh
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Andrew M Howe
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Emma Farrell
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Elizabeth Hegedus
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
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Ritchie HE, Oakes D, Farrell E, Ababneh D, Howe A. Fetal hypoxia and hyperglycemia in the formation of phenytoin-induced cleft lip and maxillary hypoplasia. Epilepsia Open 2019; 4:443-451. [PMID: 31440725 PMCID: PMC6698684 DOI: 10.1002/epi4.12352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Phenytoin exposure during the first trimester of pregnancy increases the risk of maxillary hypoplasia and cleft lip. The etiology of phenytoin embryopathy is unknown. Interestingly, phenytoin is also known to induce hyperglycemia in humans as well as rats. This study uses a rat model of fetal phenytoin syndrome to examine the role of hyperoxia, hyperglycemia, and arachidonic acid deficiency in the development of cleft lip and maxillary hypoplasia. METHODS Pregnant rats were dosed with phenytoin during the critical period of lip development (day 11 of pregnancy) with or without supplemental oxygen, insulin, or arachidonic acid. The fetuses from all studies were examined at term. RESULTS The frequency of cleft lip and maxillary hypoplasia was reduced by treating dams at the time of phenytoin exposure with either increased oxygen or insulin. However, in fetuses from phenytoin-treated dams dosed with arachidonic acid, the incidence of severe lip deformities remained the same although there was an increase in normal and mildly affected fetuses. Interestingly, this occurred in embryos from hyperglycemic dams. SIGNIFICANCE Together, the results from these experiments suggest phenytoin-induced malformations may be a multifactorial process as malformations were not solely linked to a hyperglycemic state of the dam.
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Affiliation(s)
- Helen E. Ritchie
- School of Medical Sciences, Faculty of Medicine and HealthUniversity of SydneySydneyNew South WalesAustralia
| | - Diana Oakes
- School of Medical Sciences, Faculty of Medicine and HealthUniversity of SydneySydneyNew South WalesAustralia
| | - Emma Farrell
- School of Medical Sciences, Faculty of Medicine and HealthUniversity of SydneySydneyNew South WalesAustralia
| | - Deena Ababneh
- Department of Basic Engineering Sciences, College of EngineeringImam Abdulrahman bin Faisal UniversityDammamSaudi Arabia
| | - Andrew Howe
- School of Medical Sciences, Faculty of Medicine and HealthUniversity of SydneySydneyNew South WalesAustralia
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The effect of anti-emetic drugs on rat embryonic heart activity. Reprod Toxicol 2019; 87:140-145. [PMID: 31199962 DOI: 10.1016/j.reprotox.2019.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/05/2019] [Accepted: 06/10/2019] [Indexed: 02/07/2023]
Abstract
Nausea and vomiting of pregnancy (NVP) is the most common medical complaint during pregnancy affecting up to 70% of pregnant women worldwide. Some antiemetic medications (AEM) (droperidol, domperidone, granisetron, metoclopramide and trifluoperazine) used to treat NVP have the unwanted side effect of hERG blockade. The hERG potassium channel is essential for normal heart rhythm in both the adult human and the human and rat embryo. Animal studies show hERG blockade in the embryo causes bradycardia and arrhythmia leading to cardiovascular malformations and other birth defects. Whole rat embryo in vitro culture was used to determine the effect of the above listed AEM and meclizine on the heart rate of Gestational day 13 rat embryos. These embryos are similar in size and heart development to 5-6-week human embryo. The results showed that all of the AEMs caused a concentration-dependent bradycardia. Droperidol had the lowest margin of safety.
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Ritchie HE, Telenius C, Gustaffson E, Webster WS. The effects of nifedipine and ivabradine on the functionality of the early rat embryonic heart. Are these drugs a risk in early human pregnancy? Birth Defects Res 2019; 111:281-288. [PMID: 30653849 DOI: 10.1002/bdr2.1457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/10/2018] [Accepted: 12/28/2018] [Indexed: 01/13/2023]
Abstract
BACKGROUND When the human heart begins its earliest contractions from day 21, it lacks a functional autonomic nerve supply. Instead, contractions are generated by regular calcium transients later augmented by the funny current (If ) produced by sinoatrial-like cells. This study examined effects of blocking these currents in the early rat embryonic heart. METHODS Rat embryos were incubated in vitro with either the calcium channel blocker nifedipine and/or the funny current (If ) blocker ivabradine for 1 hr to examine the effects of these drugs on the activity of the embryonic heart. RESULTS On gestational day (GD) 10, nifedipine (0.45-1.8 μM) caused asystole at high concentrations (8/10 embryos at 1.8 μM and 3/10 embryos at 0.9 μM) and markedly increased embryonic heart rate (EHR) in all surviving embryos but likely reduced blood flow due to weak contractions. Ivabradine (1.5 μM) caused a 29% reduction in EHR in GD 10 embryos and a greater than 50% reduction in EHR for GD 11-14 embryos. Combined exposure to both nifedipine and ivabradine resulted in an additive effect. The increased EHR due to nifedipine was reduced by the ivabradine. CONCLUSION The results suggest that exposure to nifedipine in human pregnancy 3-4 weeks postfertilization may cause a direct effect on the embryonic heart resulting in reduced blood flow leading to abnormal heart and/or blood vessel development and/or embryonic death. Accidental exposure to ivabradine in the organogenic period would be expected to cause embryonic bradycardia, hypoxia, malformations, and embryonic death. This drug is currently contraindicated in pregnancy.
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Affiliation(s)
- Helen E Ritchie
- Discipline of Biomedical Sciences, Sydney School of Medical Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Carolina Telenius
- Discipline of Anatomy and Histology, Sydney School of Medical Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Elin Gustaffson
- Discipline of Anatomy and Histology, Sydney School of Medical Science, The University of Sydney, Sydney, New South Wales, Australia
| | - William S Webster
- Discipline of Anatomy and Histology, Sydney School of Medical Science, The University of Sydney, Sydney, New South Wales, Australia
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Ritchie HE, Oakes DJ, Kennedy D, Polson JW. Early Gestational Hypoxia and Adverse Developmental Outcomes. Birth Defects Res 2018; 109:1358-1376. [PMID: 29105381 DOI: 10.1002/bdr2.1136] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/01/2017] [Indexed: 12/14/2022]
Abstract
Hypoxia is a normal and essential part of embryonic development. However, this state may leave the embryo vulnerable to damage when oxygen supply is disturbed. Embryofetal response to hypoxia is dependent on duration and depth of hypoxia, as well as developmental stage. Early postimplantation rat embryos were resilient to hypoxia, with many surviving up to 1.5 hr of uterine clamping, while most mid-gestation embryos were dead after 1 hour of clamping. Survivors were small and many had a range of defects, principally terminal transverse limb reduction defects. Similar patterns of malformations occurred when embryonic hypoxia was induced by maternal hypoxia, interruption of uteroplacental flow, or perfusion and embryonic bradycardia. There is good evidence that high altitude pregnancies are associated with smaller babies and increased risk of some malformations, but these results are complicated by increased risk of pre-eclampsia. Early onset pre-eclampsia itself is associated with small for dates and increased risk of atrio-ventricular septal defects. Limb defects have clearly been associated with chorionic villus sampling, cocaine, and misoprostol use. Similar defects are also observed with increased frequency among fetuses who are homozygous for thalassemia. Drugs that block the potassium current, whether as the prime site of action or as a side effect, are highly teratogenic in experimental animals. They induce embryonic bradycardia, hypoxia, hemorrhage, and blisters, leading to transverse limb defects as well as craniofacial and cardiovascular defects. While evidence linking these drugs to birth defects in humans is not compelling, the reason may methodological rather than biological. Birth Defects Research 109:1358-1376, 2017.© 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Helen E Ritchie
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Sydney, NSW
| | - Diana J Oakes
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Sydney, NSW
| | | | - Jaimie W Polson
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Sydney, NSW
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Prestipino L, Polson JW, Brolin E, Ritchie HE. Long-term programming effects on blood pressure following gestational exposure to the I Kr blocker Dofetilide. Physiol Rep 2018; 6:e13621. [PMID: 29504284 PMCID: PMC5835481 DOI: 10.14814/phy2.13621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 11/24/2022] Open
Abstract
A slow embryonic heart rate in early-mid gestation is associated with increased risk of embryonic death and malformation, however, the long-term consequences remain unknown. We administered Dofetilide (Dof, 2.5 mg/kg), a drug that produces embryo-specific bradycardia, to pregnant rats from gestational days 11-14. Embryonic heart rate and rhythm were determined using embryo culture. Cardiovascular function was assessed in surviving adult offspring at rest, during acute psychological stress (air jet stress, AJS), and after 7 days of repeated AJS. Dof reduced embryonic HR by 40% for ~8 h on each of the treatment days. On postnatal day 3, Dof offspring were ~10% smaller. Blood pressure was elevated in adult Dof rats (systolic blood pressure, night: 103.8 ± 3.9 vs. 111.2 ± 3.0 mmHg, P = 0.01). While the pressor response to AJS was similar in both groups (control 17.7 ± 3.4; Dof 18.9 ± 0.9 mmHg, P = 0.74), after 7 days repeated AJS, clear habituation was present in control (P = 0.0001) but not Dof offspring (P = 0.48). Only Dof offspring showed a small increase in resting blood pressure after 7 days repeated stress (+3.9 ± 1.7 mmHg, P = 0.05). The results indicate that embryonic bradycardia programs hypertension and impaired stress adaptation, and have implications for the maternal use of cardioactive drugs during pregnancy.
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Affiliation(s)
- Louise Prestipino
- School of Medical Sciences and Bosch InstituteSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Jaimie W. Polson
- School of Medical Sciences and Bosch InstituteSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Elisabeth Brolin
- School of Medical Sciences and Bosch InstituteSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Helen E. Ritchie
- School of Medical Sciences and Bosch InstituteSydney Medical SchoolThe University of SydneySydneyNSWAustralia
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Ritchie HE, Moore NP, Webster WS. Editor’s Highlight: Ethylene Glycol Teratogenicity: A Role for Embryonic Acidosis? Toxicol Sci 2017; 161:421-430. [DOI: 10.1093/toxsci/kfx225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Ritchie HE, Ragnerstam C, Gustafsson E, Jonsson JM, Webster WS. Control of the heart rate of rat embryos during the organogenic period. HYPOXIA 2016; 4:147-159. [PMID: 27878135 PMCID: PMC5108485 DOI: 10.2147/hp.s115050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to gain insight into whether the first trimester embryo could control its own heart rate (HR) in response to hypoxia. The gestational day 13 rat embryo is a good model for the human embryo at 5–6 weeks gestation, as the heart is comparable in development and, like the human embryo, has no functional autonomic nerve supply at this stage. Utilizing a whole-embryo culture technique, we examined the effects of different pharmacological agents on HR under normoxic (95% oxygen) and hypoxic (20% oxygen) conditions. Oxygen concentrations ≤60% caused a concentration-dependent decrease in HR from normal levels of ~210 bpm. An adenosine agonist, AMP-activated protein kinase (AMPK) activator and KATP channel opener all caused bradycardia in normoxic conditions; however, putative antagonists for these systems failed to prevent or ameliorate hypoxia-induced bradycardia. This suggests that the activation of one or more of these systems is not the primary cause of the observed hypoxia-induced bradycardia. Inhibition of oxidative phosphorylation also decreased HR in normoxic conditions, highlighting the importance of ATP levels. The β-blocker metoprolol caused a concentration-dependent reduction in HR supporting reports that β1-adrenergic receptors are present in the early rat embryonic heart. The cAMP inducer colforsin induced a positive chronotropic effect in both normoxic and hypoxic conditions. Overall, the embryonic HR at this stage of development is responsive to the level of oxygenation, probably as a consequence of its influence on ATP production.
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Affiliation(s)
- Helen E Ritchie
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Lidcombe
| | - Carolina Ragnerstam
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Elin Gustafsson
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Johanna M Jonsson
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - William S Webster
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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Ritchie H, Oakes D, Hung TT, Hegedus E, Sood S, Webster W. The Effect of Dofetilide on the Heart Rate of GD11 and GD13 Rat Embryos, in vivo, Using Ultrasound. ACTA ACUST UNITED AC 2015; 104:196-203. [DOI: 10.1002/bdrb.21162] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/28/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Helen Ritchie
- Discipline of Biomedical Science; University of Sydney; New South Wales Australia
| | - Diana Oakes
- Discipline of Biomedical Science; University of Sydney; New South Wales Australia
| | - Tzong-tyng Hung
- Biological Resources Imaging Laboratory; University of New South Wales; New South Wales Australia
| | - Elizabeth Hegedus
- Discipline of Biomedical Science; University of Sydney; New South Wales Australia
| | - Shreya Sood
- Discipline of Biomedical Science; University of Sydney; New South Wales Australia
| | - William Webster
- Department of Anatomy and Histology; The University of Sydney; New South Wales Australia
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Ritchie HE, Hung TT, Hegedus E. The effect of dofetilide on embryonic heart rate of rat embryos during early development using high-resolution ultrasound. Reprod Toxicol 2015. [DOI: 10.1016/j.reprotox.2015.07.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chen H, Chan JYW, Li S, Liu JJ, Wyman IW, Lee SMY, Macartney DH, Wang R. In vivo reversal of general anesthesia by cucurbit[7]uril with zebrafish models. RSC Adv 2015. [DOI: 10.1039/c5ra09406b] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate for the first time that cucurbit[7]uril effectively reversed general anesthesia induced by tricaine in zebrafish models.
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Affiliation(s)
- Huanxian Chen
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Taipa
- China
| | - Judy Y. W. Chan
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Taipa
- China
| | - Shengke Li
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Taipa
- China
| | | | - Ian W. Wyman
- Department of Chemistry
- Queen's University
- Kingston
- Canada
| | - Simon M. Y. Lee
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Taipa
- China
| | | | - Ruibing Wang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Taipa
- China
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