Improvements in Clinical Trials Information Will Improve the Reproductive Health and Fertility of Cancer Patients

There are a number of barriers that result in cancer patients not being referred for oncofertility care, which include knowledge about reproductive risks of antineoplastic agents. Without this information, clinicians do not always make recommendations for oncofertility care. The objective of this study was to describe the level of reproductive information and recommendations that clinicians have available in clinical trial protocols regarding oncofertility management and follow-up, and the information that patients may receive in clinical trials patient information sheets or consent forms. A literature review of the 71 antineoplastic drugs included in the 68 clinical trial protocols showed that 68% of the antineoplastic drugs had gonadotoxic animal data, 32% had gonadotoxic human data, 83% had teratogenic animal data, and 32% had teratogenic human data. When the clinical trial protocols were reviewed, only 22% of the protocols reported the teratogenic risks and 32% of the protocols reported the gonadotoxic risk. Only 56% of phase 3 protocols had gonadotoxic information and 13% of phase 3 protocols had teratogenic information. Nine percent of the protocols provided fertility preservation recommendations and 4% provided reproductive information in the follow-up and survivorship period. Twenty-six percent had a section in the clinical trials protocol, which identified oncofertility information easily. When gonadotoxic and teratogenic effects of treatment were known, they were not consistently included in the clinical trial protocols and the lack of data for new drugs was not reported. Very few protocols gave recommendations for oncofertility management and follow-up following the completion of cancer treatment. The research team proposes a number of recommendations that should be required for clinicians and pharmaceutical companies developing new trials.

Methylnitrosourea induces neural progenitor cell apoptosis and microcephaly in mouse embryos

BACKGROUND

Prenatal exposure to methylnitrosourea (MNU), an alkylating agent, induces microcephaly in mice. However, its pathogenetic mechanism has not been clarified, especially that in the development of the cerebral cortex.

METHODS

ICR mice were treated with MNU at 10 mg/kg intraperitoneally on day 13.5 or 15.5 of gestation, and the embryos were observed histologically 24 hr after treatment with MNU or at term. To clarify the pathogenesis of microcephaly and histological changes, especially apoptosis, neurogenesis, and neural migration/positioning, we performed histological analysis employing a cell-specific labeling experiment using thymidine-like substances (BrdU, CldU, and IdU) and markers of neurons/neural stem cells.

RESULTS

Histological abnormalities of the dorsal telencephalon, and the excessive cell death of proliferative neural progenitor/stem cells were noted in the MNU-treated embryos. The highest frequencies of cell death occurred at 36 hr after MNU treatment, and little or no neurogenesis was observed in the ventricular zone of the dorsal telencephalon. Abnormality of the radial migration was caused by the reduction of radial fibers in the radial glias. Birth-date analysis revealed the abnormal positioning of neurons and aberrant lamination of the cerebral cortex.

CONCLUSIONS

Our data suggest that prenatal exposure to MNU induces the excessive cell death of neural precursor/stem cells, and the defective development of the cerebral cortex, resulting in microcephalic abnormalities.

Maternal exposure to nitrate from drinking water and diet and risk for neural tube defects

In this population-based case-control study conducted in California between June 1989 and May 1991, the authors investigated the association between maternal periconceptional exposure to nitrate from drinking water and diet and risk for neural tube defects. The mothers of 538 cases and 539 nonmalformed controls were interviewed regarding residential history, consumption of tap water at home, and dietary intake during the periconceptional period. Dietary nitrate exposure was not associated with increased risk for neural tube defects. Exposure to nitrate in drinking water at concentrations above the 45 mg/liter maximum contaminant level was associated with increased risk for anencephaly (odds ratio (OR) = 4.0, 95% confidence interval (CI): 1.0, 15.4), but not for spina bifida. Increased risks for anencephaly were observed at nitrate levels below the maximum contaminant level among groundwater drinkers only (OR = 2.1, 95% CI: 1.1,4.1 for 5-15 mg/liter; OR = 2.3, 95% CI: 1.1, 4.5 for 16-35 mg/liter; and OR = 6.9, 95% CI: 1.9, 24.9 for 36-67 mg/liter compared with <5 mg/liter). Adjustment for identified risk factors for anencephaly did not substantially alter these associations, nor did control for maternal dietary nitrate, total vitamin C intake, and quantity of tap water consumed. The lack of an observed elevation in risk for anencephaly in association with exposure to mixed water containing nitrate at levels comparable with the concentration in groundwater may indicate that something other than nitrate accounts for these findings.

Late-onset cerebellar degeneration in mice induced transplacentally by methylnitrosourea

A late-onset degenerative disease in the cerebellum was produced in the offspring of mice exposed to 1 mg/kg of the direct-acting DNA alkylating agent methylnitrosourea (MNU) on day 16 of gestation. This intrauterine exposure to MNU also provoked a progressive retinal degeneration that was described elsewhere. Mild ataxia in the MNU-exposed animals was expressed by 20 weeks of age. Although animals appeared normal in the immediate post-natal period, quantitative histological evaluation of cerebellar coronal sections indicated that MNU-exposed animals had a significantly greater number of pyknotic Purkinje cells than age-matched controls. The number of pyknotic Purkinje cells declined with age in the drug exposed animals; however, the percentage of pyknotic Purkinje cells to total number of Purkinje cells still was greater in MNU-induced animals at 36 weeks than in controls, suggesting that a slow degenerative process was ongoing in the MNU-exposed animals. Furthermore, the folia were grossly disrupted in 90% of the older MNU-exposed animals (ages greater than 12 weeks), suggesting permanent cerebellar disruption macroscopically. Such intrauterine exposure to low doses of alkylating agents may be potentially useful in modeling degenerative neuronal diseases.

Birth defects and household water supply. Epidemiological studies in the Mount Gambier region of South Australia

We report a descriptive study indicating a localised excess of congenital malformations in Mount Gambier, South Australia, and summary results of a subsequent case-control study showing an association between the occurrence of congenital malformations and the consumption of underground water by pregnant women. The internal cohesion of the data analyses, and the plausibility conferred by experimental evidence, suggests that the underground water, and its elevated concentration of nitrates, may warrant further consideration as a source of human teratogens.

Nucleic acids and protein in brains and cerebella of rats transplacentally exposed to ethylnitrosourea

Female rats were injected (IP) with either 15, 60, 100, or 150 mg/kg N-ethyl-N-nitrosourea (ENU) on gestation day 18. The neurochemical development of the whole brain and the cerebellum was studied in 21- and 60-day old offspring; pups from mothers subjected to 150 mg/kg were examined only at 21 days. Brain weights were significantly reduced in all ENU-exposed groups at 21 days, and the 60 mg/kg group at 60 days. Whole brain DNA and protein concentrations of most ENU groups were elevated at 21 days and RNA content and RNA/DNA ratios were subnormal. Deficits in whole brain DNA content were observed in all ENU groups on day 60. Cerebellar weight was reduced in the 60 and 150 mg/kg groups on day 21 and in the 100 mg/Kg group on day 60. At 21 days, reductions in cerebellar DNA and RNA concentrations and contents were often recorded in several ENU groups. Cerebellar DNA concentration and content of the 60 and 100 mg/kg groups remained subnormal at 60 days of age. In general, a dose-response effect was evident in the number and magnitude of neurochemical alterations produced by ENU. These data suggest that transplacental exposure to ENU, a potent neurotropic carcinogen, affects the biochemical maturation of the brain.