Potentiating effects of caffeine on the cardiovascular teratogenicity of ephedrine in chick embryos

Risk of Major Congenital Malformations Associated with the Use of Japanese Traditional (Kampo) Medicine Containing Ephedra During the First Trimester of Pregnancy

BACKGROUND

Japanese traditional (Kampo) medicines containing ephedra may be used to treat colds during pregnancy. There are reports that ephedrine, a component of ephedra, has a risk of teratogenicity; however, the evidence remains equivocal.

OBJECTIVE

This study aimed to evaluate the risk of major congenital malformations (MCMs) associated with exposure to Kampo medicines containing ephedra during the first trimester of pregnancy using the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study).

METHODS

To 23,730 mother-infant pairs who participated in the TMM BirThree Cohort Study from July 2013 to March 2017, questionnaires in early and middle pregnancy were distributed approximately at weeks 12 and 26 of pregnancy, respectively. Infants' risk of MCMs in women who used Kampo medicines containing ephedra or acetaminophen during the first trimester was assessed, and the odds ratios (ORs) were estimated with unadjusted and adjusted analyses.

RESULTS

Among 20,879 women, acetaminophen and Kampo medicines containing ephedra were used in 665 (3.19%) and 376 (1.80%) women, respectively, in the first trimester. Among the infants born to the mothers who used acetaminophen or Kampo medicine containing ephedra during the first trimester, 11 (1.65%) and 8 (2.13%), respectively, had overall MCMs. OR of overall MCMs was higher in women who used Kampo medicines containing ephedra than in those who used acetaminophen in the first trimester (adjusted OR, 1.45; 95% confidence interval (CIs), 0.57-3.71); however, the difference was not statistically significant.

CONCLUSIONS

In this study, there was no statistically significant association between the use of Kampo medicines containing ephedra during the first trimester of pregnancy and the risk of MCMs. Although some point estimates of ORs exceeded 1.00, the absolute magnitude of any increased risks would be low.

The impact of caffeine on connexin expression in the embryonic chick cardiomyocyte micromass culture system

Cardiomyocytes are electrically coupled by gap junctions, defined as clusters of low-resistance multisubunit transmembrane channels composed of connexins (Cxs). The expression of Cx40, Cx43 and Cx45, which are present in cardiomyocytes, is known to be developmentally regulated. This study investigates the premise that alterations in gap junction proteins are one of the mechanisms by which teratogens may act. Specifically, those molecules known to be teratogenic in humans could cause their effects via disruption of cell-to-cell communication pathways, resulting in an inability to co-ordinate tissue development. Caffeine significantly inhibited contractile activity at concentrations above and including 1500 μm (P < 0.05), while not affecting cell viability and total protein, in the embryonic chick cardiomyocyte micromass culture system. The effects of caffeine on key cardiac gap junction protein (Cx40, Cx43 and Cx45) expression were analysed using immunocytochemistry and in-cell Western blotting. The results indicated that caffeine altered the expression pattern of Cx40, Cx43 and Cx45 at non-cytotoxic concentrations (≥2000 μm), i.e., at concentrations that did not affect total cell protein and cell viability. In addition the effects of caffeine on cardiomyocyte formation and function (contractile activity score) were correlated with modulation of Cxs (Cx40, Cx43 and Cx45) expression, at above and including 2000 μm caffeine concentrations (P < 0.05). These experiments provide evidence that embryonic chick cardiomyocyte micromass culture may be a useful in vitro method for mechanistic studies of perturbation of embryonic heart development. Copyright © 2015 John Wiley & Sons, Ltd.

A descriptive study to provide evidence of the teratogenic and cellular effects of sibutramine and ephedrine on cardiac- and liver-tissue of chick embryos

Exposure to drugs during pregnancy is a major concern, as some teratogenic compounds can influence normal foetal development. Although the use of drugs during pregnancy should generally be avoided, exposure of the developing foetus to teratogens may occur unknowingly since these compounds may be hidden in products that are being marketed as "all natural." The aim of the current study was to investigate the possible teratogenic and cellular effects of sibutramine-a serotonin-norepinephrine reuptake inhibitor used in the treatment of obesity-on the heart and liver tissue of chick embryos. Ephedrine was used as a positive control. The chick embryo model was chosen because it has been used in studying developmental and experimental biology and teratology with great success. The embryos were exposed to three different concentrations of sibutramine and ephedrine respectively. The results obtained revealed that both compounds exhibited embryotoxicity when compared to the control groups. Liver and heart tissue of the exposed embryos was severely affected by these compounds in a dose-related manner. Morphology similar to that of muscle dystrophy was observed in the heart, where the muscle tissue was infiltrated by adipose and connective tissue. Severe liver steatosis was also noted. A more in-depth investigation into the molecular pathways involved might provide more information on the exact mechanism of toxicity of these products influencing embryonic development.

Nitrosatable drug exposure during the first trimester of pregnancy and selected congenital malformations

BACKGROUND

Nitrosatable drugs can react with nitrite in the stomach to form N-nitroso compounds, and results from animal studies suggest that N-nitroso compounds are teratogens. With data from the National Birth Defects Prevention Study, the relation between prenatal exposure to nitrosatable drugs and limb deficiencies, oral cleft, and heart malformations in offspring was examined.

METHODS

Maternal reports of drugs taken during the first trimester of pregnancy were classified with respect to nitrosatability for mothers of 741 babies with limb deficiencies, 2774 with oral cleft malformations, 8091 with congenital heart malformations, and 6807 without major congenital malformations. Nitrite intake was estimated from maternal responses to a food frequency questionnaire.

RESULTS

Isolated transverse limb deficiencies and atrioventricular septal defects were associated with secondary amine drug exposures (adjusted odds ratios [aORs], 1.51; 95% confidence limit [CI], 1.11-2.06 and aOR, 1.97; 95% CI, 1.19-3.26, respectively). Tertiary amines were associated with hypoplastic left heart syndrome (aOR, 1.50; 95% CI, 1.10-2.04) and single ventricle (aOR, 1.61; 95% CI, 1.06-2.45). These two malformations were also significantly associated with amide drugs. For several malformations, the strongest associations with nitrosatable drug use occurred among mothers with the highest estimated dietary nitrite intake, especially for secondary amines and atrioventricular septal defects (highest tertile of nitrite, aOR, 3.30; 95% CI, 1.44-7.58).

CONCLUSION

Prenatal exposure to nitrosatable drugs may be associated with several congenital malformations, especially with higher nitrite intake. The possible interaction between nitrosatable drugs and dietary nitrite on risk of congenital malformations warrants further attention.

Developmental toxicity of Citrus aurantium in rats

BACKGROUND

Ephedra was commonly used in herbal products marketed for weight loss until safety concerns forced its removal from products. Even before the ban, manufacturers had begun to replace ephedra with other compounds, including Citrus aurantium, or bitter orange. The major component in the bitter orange extract is synephrine which is chemically similar to ephedrine. The purpose of this study was to determine if relatively pure synephrine or synephrine present as a constituent of a bitter orange extract produced developmental toxicity in rats.

METHOD

Sprague-Dawley rats were dosed daily by gavage with one of several different doses of synephrine from one of two different extracts. Caffeine was added to some doses. Animals were sacrificed on GD 21, and fetuses were examined for the presence of various developmental toxic endpoints.

RESULTS AND CONCLUSION

At doses up to 100 mg synephrine/kg body weight, there were no adverse effects on embryolethality, fetal weight, or incidences of gross, visceral, or skeletal abnormalities. There was a decrease in maternal weight at 50 mg synephrine/kg body weight when given as the 6% synephrine extract with 25 mg caffeine/kg body weight; there was also a decrease in maternal weight in the caffeine only group. This decrease in body weight may have been due to decreased food consumption which was also observed in these two groups. Overall, doses of up to 100 mg synephrine/kg body weight did not produce developmental toxicity in Sprague-Dawley rats.

A prospective cohort study of pregnancy outcomes of women inadvertently exposed to methylephedrine in the 1st trimester of pregnancy

No information is currently available on the safety of methylephedrine, a component of various cold medications available in South Korea. With previous approval by an Institutional Review Board, 349 women inadvertently exposed to methylephedrine during the 1st trimester of pregnancy and an age- and gravidity-matched control group, were enrolled in a prospective cohort study. Study outcomes, for example gestational age at birth, birth weight and major and minor malformations were evaluated in 282 cases and 280 controls. Exposure to methylephedrine was at a gestational age of 4.0 weeks (median), at doses ranging from 52.5 to 1,575 mg/day, for a median duration of 3 (range: 1-30) days. No differences were observed between cases and controls in any of the pregnancy outcomes studied. There were 4/265 (1.5%) babies born with major malformations in the case group and 4/260 (1.5%) in the control group. In conclusion, inadvertent exposure to methylephedrine as a component of over-the counter oral cold remedies in early pregnancy was not associated with an increased rate of adverse pregnancy outcomes. Co-exposure with acetaminophen, cigarette smoking or alcohol did not appear to modify the outcomes.

Teratogen update: pseudoephedrine

Pseudoephedrine is contained in decongestants such as the Sudafed line of products. It is an alpha-adrenergic receptor agonist, which causes blood vessel constriction, including the therapeutic effect of reducing airflow resistance in the nasal cavity. Pseudoephedrine is one of the most commonly used medications in pregnancy, with an estimated 25% of women exposed. It has been demonstrated that alpha-adrenergic receptor agonists slow uterine blood flow, but their effects have not been studied in relation to most reproductive outcomes in animals or humans. Two analyses of health maintenance organization pharmacy data identified 9 malformed infants among 902 first-trimester pseudoephedrine exposures, suggesting no association with birth defects overall; however, studies of such data sets often lack sufficient power to identify risks for specific birth defects. The related compounds, epinephrine, ephedrine, and phenylephrine, have been associated with hemorrhages and cardiovascular and limb malformations in animal models. Risk of ventricular septal defects was associated with decongestant use in pregnant women in 1 recent study. The vasoconstrictive effects of these drugs raise the hypothesis that their use in early pregnancy might increase the risk of vascular disruption defects. Case-control studies, which often do have power to identify risks related to specific birth defects, have explored this hypothesis. Decongestant use in the first trimester has been associated with small increases in risks of 3 defects thought to arise, at least in some instances, from vascular disruption-gastroschisis, small intestinal atresia, and hemifacial microsomia. These findings are somewhat consistent in terms of magnitude of effect and suggest that risks are even greater among women also exposed to the vasoconstrictive effects of cigarette smoking. There are, however, limitations to these studies, including the possibilities of inaccurate recall of exposures and confounding by indication. In addition, the majority of decongestant use is in oral form and the question of whether intranasal formulations carry risk has not been adequately addressed.

Decrease in calcitonin-containing cells in truncus arteriosus

Experimental studies in chick embryos have demonstrated that truncus arteriosus (TA), a form of conotruncal cardiac defect, is due to abnormalities in the cranial neural crest. However, no data are available to support this hypothesis in humans with isolated TA. In the present study, the assessment of calcitonin immunoreactive cells (C-cells) has been employed to evaluate whether or not the proportion of thyroid cells derived from the cranial neural crest is normal in patients with isolated TA. Thyroid sections from 15 such patients in which no other extracardiac malformations were neither clinically nor pathologically found, and from 11 control age-matched patients were studied immunohistochemically at autopsy in order to determine the number and distribution of calcitonin-containing cells. The volume density of C-cells (0.888%) and the number of C-cells per follicle (0.991) was significantly lower in patients with TA than in control patients (3.475%, and 2.367, respectively). The decrease of neural crest-derived cells in the thyroid of patients with "isolated" TA documents more extent abnormalities than clinically suspected and supports the hypothesis of neural crest disturbance as the pathogenetic factor responsible for this heart malformation.

Potentiating effects of forskolin on the cardiovascular teratogenicity of ephedrine in chick embryos

The effects of forskolin on the teratogenicity of ephedrine in the developing chick heart were studied. Forskolin was administered to 4-day chick embryos (Hamburger-Hamilton stage 24) together with ephedrine at doses at which each agent alone caused minimal embryotoxicity. The embryos were examined for malformations on day 14 of incubation. The frequency of malformed embryos exposed to ephedrine (0.5 or 5 mumol) alone was 8 and 26%, respectively, and significantly increased to 47-72% in the presence of 1 nmol forskolin. Forskolin (1 nmol) alone did not induce a significant number of cardiac malformations. These results suggest that the increase in cAMP through stimulation of adenylate cyclase by forskolin is associated with the potentiation of ephedrine-induced cardiovascular malformations in the chick.

The induction of dominant lethal mutations upon chronic administration of khat (Catha edulis) in albino mice

The mutagenicity of a methanolic extract of khat has been evaluated on male germ cells using the dominant lethal test in albino mice. An aqueous solution of khat extract was administered orally in doses of 50, 100 and 200 mg/kg body wt., respectively, to 3 different groups of male mice for a period of 6 weeks. At the end of treatment each male mouse was allowed to mate with 2 different groups of 3 females each, on 2 consecutive weeks. These females were necropsied on the 13th day of their presumptive mating, and the number of implants in each female and the ratio of live and dead embryos were determined. The results of this study showed that the treatment of male mice over a period of 6 weeks produced a dose-dependent reduction in the rate of fertility in the first week after mating, which was irreversible in the second week at the highest dose (200 mg/kg). Khat extract also induced post-implantation loss during the first week following treatment. However, a comparison of the results of the first and second weeks showed a reversible pattern of dominant lethality.

The teratogenic effect of forskolin on cardiovascular development in the chick embryo

The cardiovascular teratogenicity and embryotoxicity of forskolin, a potent activator of adenylate cyclase, was studied in the chick embryo. The drug was topically applied to the surface of the chorioallantoic membrane in the vicinity of the embryonic heart on the 4th day of incubation (Hamburger-Hamilton developmental stage 24). Cardiovascular malformations were induced in 51% of embryos treated with forskolin doses larger than 1 x 10(-8) mol/egg. Major malformations included remnant of the left 4th aortic arch and ventricular septal defect. These results indicate that forskolin induces cardiovascular malformations in the chick embryo and suggest that increased levels of cyclic 3',5'-adenosine monophosphate produced by forskolin may be related to the malformations observed.

Cytological effects of khat (Catha edulis) in somatic and male germ cells of mice

Cytological effects of khat (Catha edulis), a popular drug of abuse from Southern Arabia and Eastern Africa, have been studied in Swiss albino mice. The studies on the somatic system involved the use of micronucleus test and the cytological analysis of the mitotic index in the femoral cells of mice. In the micronucleus test, the mice were treated with different doses of khat extract (125, 250 and 500 mg/kg, p.o.) 30 and 6 hours before sacrificing the animals. The polychromatic erythrocytes were screened for the induction of micronuclei. For the analysis of bone marrow cytotoxicity, the mice were treated with the dose of 125, 250 and 500 mg/kg, body weight, p.o. daily for 5 consecutive days. The animals were sacrificed and the femoral cells were microscopically examined for the mitoses. Following the same schedule of treatment, studies on the cytogenetic analysis of meiotic chromosomal aberrations and the sperm head abnormality were undertaken. Khat extract significantly increased the frequency of micronucleated polychromatic erythrocytes, induced bone marrow depression and reduced the mitotic index of the somatic cells. It induced significant chromosomal aberrations viz., aneuploids, autosomal univalents, univalents of the sex chromosomes and polyploids. The frequency of abnormal sperms was also increased.

Clastogenic evaluation of cathinone and amphetamine in somatic cells of mice

Clastogenic effects of cathinone, the active principle from khat (Catha edulis) and amphetamine, a compound having similar chemical structure and pharmacological activity, have been studied on the somatic cells of mice. Both of them produced marked clastogenic activity and affected the cell proliferation in the bone marrow of mice. They induced a significant increase in the frequency of micronucleated polychromatic erythrocytes at higher doses. These results substantiate our earlier observations on the clastogenic and mitodepressive activity of cathinone on the meristematic region of Allium cepa, and indicate that cathinone may be responsible for the mutagenic effect of khat reported by other workers. The clastogenic effects of amphetamine are being reported for the first time. Further studies are required to substantiate these findings and to study whether cathinone and amphetamine produce a direct clastogenic effect or whether they act as spindle poisons.