ISOTRETINOIN-INDUCED CRANIOFACIAL MALFORMATIONS

拟议的研究涉及使用我们拥有的动物模型， 开发用于研究异维甲酸诱导的畸形 （13-顺式-视黄酸，Accutane）;与 这种药物在人体内引起的症状 自9月推出以来， 1982年，异维A酸已成为一种广泛使用的药物， 用于治疗严重的囊性痤疮。 与其他情况一样， 类维生素A（维生素A），异维A酸已知是致畸的， 实验动物 尽管有怀孕期间使用的警告， 已经有200到300次已知的接触。 在那些 已经被允许进入足月，颅面，心脏 和胸腺异常 我们的动物模型中的畸形与人类中看到的非常相似 新生儿和它已经有可能表明，干扰神经 嵴发育是其发病机制的主要特征。 此外，本发明还提供了一种方法， 我们有证据表明，一种代谢物，4-氧代异维甲酸（达到 血清中母体化合物浓度的3-5倍， 正在接受治疗的患者）也是致畸的。 在本申请中， 我们建议使用扫描EM完成描述性形态学研究， 光学显微镜和透射电镜。 免疫组织学程序将 可以用来帮助识别神经嵴细胞。 异维甲酸和4-氧代异维甲酸的药代动力学研究， 将完成启动。 小鼠中的维持方案 这两种化合物的血液水平与人类治疗水平相似， 水平正在发展。 母体给药后， 这些化合物在胚胎中的含量也将被确定。 关于异维A酸改变细胞内蛋白质的机制的进一步研究 该模型中神经嵴和其他细胞群的发育是 并提出了 这些措施包括使用3 H-异维甲酸和冷冻切片 放射自显影以确定化合物是否集中在波峰 其他研究表明， 使用14 C-维甲酸（14 C-全反式维甲酸）。 细胞改变 使用3 H-胸苷放射自显影术研究增殖。 还将检查纤连蛋白和细胞粘附分子的改变。

The proposed studies are concerned with the use of an animal model we have developed for the study of malformations induced by isotretinoin (13-cis-retinoic acid, Accutane); malformations which are comparable to those induced by this drug in humans. Since its introduction in September 1982, isotretinoin has become a widely used drug which is very effective for the treatment of severe cystic acne. As is the case with other retinoids (vitamin A), isotretinoin was known to be teratogenic in experimental animals. Despite warnings against use during pregnancy, there have been between 200 and 300 known exposures. In the prenancies which have been permitted to go to term, high incidences of craniofacial, heart and thymic abnormalities have occurred. Malformations in our animal model are very similar to those seen in human newborns and it has been possible to show that interference with neural crest development is a major feature in their pathogenesis. In addition, we have evidence that a metabolite, 4-oxo-isotretinoin (which reaches concentrations 3-5 times that of the parent compound in the serum of patients undergoing treatment) is also teratogenic. In this application, we propose to complete descriptive morphological studies using scanning EM, light microscopy and transmission EM. An immunohistological procedure will be utilized to assist in the identification of neural crest cells. Pharmacokinetic studies of isotretinoin and 4-oxo-isotretinoin which have been initiated will be completed. Regimens for maintenance in mice of blood levels of both compounds which are similar to human therapeutic levels are being developed. Following maternal administration, the levels of these compounds in the embryos will also be determined. Further studies concerning the mechanisms by which isotretinoin alters the development of neural crest and other cell populations in this model are also proposed. These include the use of 3H-isotretinoin and frozen section autoradiography to determine whether the compound is concentrated in crest cells at certain stages of their development as suggested by other studies using 14C-tretinoin (14C-all-transretinoic acid). Alterations in cell proliferation will be studied using 3H-thymidine autoradiography. Alterations in fibronectin and cell adhesion molecule will also be examined.