Long-Term Treatment of Azathioprine in Rats Induces Vessel Mineralization

Medial vascular calcification (mVC) is closely related to cardiovascular disease, especially in patients suffering from chronic kidney disease (CKD). Even after successful kidney transplantation, cardiovascular mortality remains increased. There is evidence that immunosuppressive drugs might influence pathophysiological mechanisms in the vessel wall. Previously, we have shown in vitro that mVC is induced in vascular smooth muscle cells (VSMCs) upon treatment with azathioprine (AZA). This effect was confirmed in the current study in an in vivo rat model treated with AZA for 24 weeks. The calcium content increased in the aortic tissue upon AZA treatment. The pathophysiologic mechanisms involve AZA catabolism to 6-thiouracil via xanthine oxidase (XO) with subsequent induction of oxidative stress. Proinflammatory cytokines, such as interleukin (IL)-1ß and IL-6, increase upon AZA treatment, both systemically and in the aortic tissue. Further, VSMCs show an increased expression of core-binding factor α-1, alkaline phosphatase and osteopontin. As the AZA effect could be decreased in NLRP3^−/− aortic rings in an ex vivo experiment, the signaling pathway might be, at least in part, dependent on the NLRP3 inflammasome. Although human studies are necessary to confirm the harmful effects of AZA on vascular stiffening, these results provide further evidence of induction of VSMC calcification under AZA treatment and its effects on vessel structure.

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.

Dose-response relationships of rat fetal skeleton variations: Relevance for risk assessment

In developmental toxicity studies, skeleton abnormalities found in fetuses at term are classified as variations or malformations. The relevance of skeleton variations for human risk assessment, however, is a controversial issue. This paper is a contribution to the discussion on the interpretation of fetal skeleton variations in the context of risk assessment. Dose-response relationships of skeleton variations and malformations induced by three antineoplastic drugs (FUDR: 5-fluoro-2'-deoxyuridine, HU: hydroxyurea and 6-MPr: 6-mercaptopurine-riboside) were evaluated. FUDR (0, 3, 14, 25, 35, 45, 55 and 65mg/kg body wt sc) and HU (0, 250, 300, 350, 400, 450, 500 and 550mg/kg body wt ip) were administered to rats on gestation day 11 (GD 11) while 6-MPr (0, 3, 7, 10 and 14mg/kg body wt sc) was given on GD 11, or on GD 12. Caesarean sections were performed on GD 21 and all fetuses were cleared and stained with alizarin red S for skeleton examination. Drugs given on GD 11 increased the incidence of thoracic and lumbar vertebra (dumbbell-shaped and bipartite ossification center (o.c.) and sternum (misaligned sternebrae) variations in a dose-dependent manner. Occurrence of zygomatic bone fused with maxilla (a variation in our rats) was also increased by HU and 6-MPr (GD 11) but it was not altered by FUDR. Spontaneous occurrence of wavy ribs was reduced by all treatments. Malformations such as cleft palate, tympanic bone absent and tibia absent were also increased in a dose-dependent manner by the three compounds. No observed effect levels (NOEL) for variations, irrespective of the compound administered, were generally lower than NOELs for malformations. In the discussion, we supported the view that any dose-related increase in the incidence of variations should be taken into account for determination of NOELs in routine studies. Increased occurrences of skeleton variations in term fetuses are also to be considered in risk assessment, unless experimental evidence exists that a particular change has no detrimental effect on the animal survival or health after birth or that it does not occur in humans.