Adriamycin produces a reproducible teratogenic model of gastrointestinal atresia in the mouse.

Gastrointestinal atresia is a major cause of bowel obstruction in the newborn. Experimental models and clinical observations have demonstrated the heterogeneous nature of its pathogenesis. A proportion is due to late intra-uterine vascular insults and some are genetic in nature. Epidemiological studies have found gastrointestinal atresia to occur with other birth defects, in particular VACTERL anomalies, suggesting that a subset of cases may result from an early disturbance to intestinal morphogenesis. Adriamycin is teratogenic in rats, producing gastrointestinal atresia and VACTERL anomalies. The mouse is the foremost mammal studied by developmental biologists, offering an expanding wealth of knowledge and scientific research techniques. The aim of this study was to create an Adriamycin mouse model for investigating the development of gastrointestinal atresia. CBA/Ca mice were accurately time-mated (n = 30). Four different doses of Adriamycin (0-saline control, 4, 5 and 6 mg/kg) at three different timings of injections were compared (12 groups). Dams received two intraperitoneal injections, 24 h apart, commencing on day 7, 7.5 or 8. Foetuses were harvested on day 18. Gastrointestinal atresia and VACTERL anomalies were examined using a dissecting microscope. Adriamycin produced type IIIa gastrointestinal atresia in six treatment groups. The effect of Adriamycin depended on the timing and dose of the injections. VACTERL anomalies were only found in four treatment groups, proposing overlapping critical embryological windows for these malformations. Gastrointestinal atresia can be induced by the teratogen Adriamycin, occurring with and without VACTERL anomalies. This produces a reproducible mouse model in which the molecular pathogenesis of gastrointestinal atresia may be studied.

Notochord-gut failure of detachment and intestinal atresia.

A spectrum of congenital anomalies have been described in an adriamycin-treated model with common features to the human pattern. Multiple intestinal atresias was part of this spectrum occurring in 25% of full-term experimental rat fetuses. The aim of this study was to examine the underlying developmental mechanism that results in intestinal atresia. Virgin timed-pregnant Sprague-Dawley rats were injected with Adriamycin i.p. at a dose of 2 mg/kg on days 6-9 of gestation. Embryos were removed on different gestational days during organogenesis and serial transverse histologic sections were examined and compared with control specimens. In experimental embryos, hindgut atresia was seen in day 12 embryos. Attachment of the intestine with the notochord was obvious observation resulting in abnormal position of the intestine. In some specimens the atretic intestine was splitting the dorsal aorta or even located behind the dorsal aorta. It is concluded that in the adriamycin-animal model, notochord-intestinal failure of detachment resulted in intestinal atresia during the beginning of organogenesis period. The possible underlying mechanisms are pinching of some endodermal cells as well as interference with normal intestinal circulation resulting in ischemic necrosis.

Jejunal atresia related to the use of toluidine blue in genetic amniocentesis in twins.

Since 1990 avoidance of methylene blue as a dye in diagnostic amniocentesis is recommended. This is the result of the observation that a high incidence of jejuno-ileal atresia appeared in twin pregnancies following intraamniotic injection of methylene blue. We report a case of jejunal atresia in twins after injection of toluidine blue. We describe the clinical course, discuss possible teratogenic mechanisms and emphasize that no synthetic dyes should be used in second trimester amniocentesis.

Midgut atresias result from abnormal development of the notochord in an Adriamycin rat model.

BACKGROUND/PURPOSE: Prenatal exposure to Adriamycin in a rat model (ARM) has been reported to lead to a spectrum of tracheoesophageal and associated malformations of the gastrointestinal tract, including multiple intestinal atresias. An abnormal relationship of the notochord with the foregut has been implicated in the formation of esophageal atresias. The authors hypothesised that midgut atresias arise from abnormal notochord development in the region of the midgut. This study was designed to examine the gut-notochord relationship during early embryonic development. METHODS: Timed pregnant Wistar rats were given 1.75 mg/kg of Adriamycin intraperitoneally on days 7, 8, and 9 of gestation. Embryos were recovered at 12-hour intervals from days 9.5 to 14, and at term. A control group was given saline instead of Adriamycin. Embryos were embedded in resin or wax, sectioned, and studied using light microscopy, paying particular attention to the notochord and surrounding structures. RESULTS: The notochord appeared identical in controls and experimental embryos on day 9.5. However, on day 10.5 the notochord was diffusely abnormal in ARM, distorted, and tethered to foregut as well as midgut compared with controls. This abnormality was not seen in control embryos. On day 12 the notochord abnormalities were more exaggerated in the region of the midgut in ARM embryos. Full-term ARM animals had esophageal and multiple intestinal atresias. CONCLUSIONS: The notochord is abnormal in the region of the developing midgut, and this may account for the occurrence of atresias found in this region.

Maternal medication use and risks of gastroschisis and small intestinal atresia.

Gastroschisis and small intestinal atresia (SIA) are birth defects that are thought to arise from vascular disruption of fetal mesenteric vessels. Previous studies of gastroschisis have suggested that risk is increased for maternal use of vasoactive over-the-counter medications, including specific analgesics and decongestants. This retrospective study evaluated the relation between maternal use of cough/cold/analgesic medications and risks of gastroschisis and SIA. From 1995 to 1999, the mothers of 206 gastroschisis cases, 126 SIA cases, and 798 controls in the United States and Canada were interviewed about medication use and illnesses. Risks of gastroschisis were elevated for use of aspirin (odds ratio = 2.7, 95% confidence interval: 1.2, 5.9), pseudoephedrine (odds ratio = 1.8, 95% confidence interval: 1.0, 3.2), acetaminophen (odds ratio = 1.5, 95% confidence interval: 1.1, 2.2), and pseudoephedrine combined with acetaminophen (odds ratio = 4.2, 95% confidence interval: 1.9, 9.2). Risks of SIA were increased for any use of pseudoephedrine (odds ratio = 2.0, 95% confidence interval: 1.0, 4.0) and for use of pseudoephedrine in combination with acetaminophen (odds ratio = 3.0, 95% confidence interval: 1.1, 8.0). Reported fever, upper respiratory infection, and allergy were not associated with risks of either defect. These findings add more evidence that aspirin use in early pregnancy increases risk of gastroschisis. Although pseudoephedrine has previously been shown to increase gastroschisis risk, findings of this study raise questions about interactions between medications and possible confounding by underlying illness.

Embryogenesis of adriamycin-induced hindgut atresia in rats.

It was proposed that the pathogenesis of multiple intestinal atresias (MIA) in human fetuses is a consequence of malformative processes of the gastrointestinal tract rather than an ischemic process. Recently, MIA has been described in adriamycin-exposed rat fetuses. The aim of this study was to describe the embryogenesis of hindgut atresia (HA) in the adriamycin animal model. Timed-pregnant Sprague-Dawley rats were injected with adriamycin on days 6-9 of gestation. Embryos were removed on different gestational days during organogenesis and histologic sections were examined and compared with control specimens. In experimental embryos, HA was seen on day 13; however, the lumen was patent on day 12. HA was associated with abnormal vascular anatomy that was obvious on days 12 and 13. It is concluded that HA in adriamycin-exposed embryos occurs at the beginning of organogenesis. Although it was associated with an obvious vascular anomaly, further studies are required to find out whether it is ischemic in origin.

Subfertility and atresias of the alimentary tract.

In a descriptive study on alimentary tract atresias (ATA), a protective effect at parity 2 compared to parity 1 led us to expect an increased rate of fertility problems in mothers of these infants. To test the hypothesis we looked at sex hormones exposures around conception in 811 cases collected between 1982 and 1993 by the France Central-East registry of malformations. Exposure to progestins was compared for combined ATA (at two or more different levels) vs. single ATA with an odds ratio of 2.51 (95% CI 0.43-9.96). Although not statistically significant, this odds ratio raises the question of an association that would be interesting to test elsewhere. Combined ATA also occurred after stimulation of ovulation more often than did isolated forms of ATA: OR = 3.52 (95% CI 0.98-10.31). Stimulation of ovulation was more often reported for infants with ATA than for those with other malformations: OR = 1.87 (95% CI: 1.24-2.81). These indications in favor of an increased risk of ATA for infants born to subfertile mothers/couples should encourage other groups to test the hypothesis on available data sets.

Intestinal atresia following intraamniotic use of dyes.

Since 1990 avoidance of methylene blue as a dye in diagnostic amniocentesis is recommended. This is a result of the observation that a high incidence of jejunoileal atresia appeared in twin pregnancies following intraamniotic injection of methylene blue. We report four further cases of jejunoileal atresia in twins after intraamniotic injection of dyes since 1991. We describe the clinical course, discuss possible teratogenic mechanisms and emphasize again that synthetic dyes should not be used in second trimester amniocentesis.

Defects and disabilities of thalidomide children.

The range of defects and disabilities in thalidomide children is very much wider than is generally realized. The defects of 154 children are described and classified. Their disabilities range from incapacitating to negligible.