[Spontaneous tumors in Syrian golden hamsters (author's transl)]

Tesaglitazar, a dual PPAR-α/γ agonist, hamster carcinogenicity, investigative animal and clinical studies

Tesaglitazar was developed as a dual peroxisome proliferator-activated receptor (PPARα/γ). To support the clinical program, a hamster carcinogenicity study was performed. The only neoplastic findings possibly related to treatment with tesaglitazar were low incidences of hemangioma and hemangiosarcoma in the liver of male animals. A high-power, two-year investigative study with interim necropsies was performed to further elucidate these findings. Treatment with tesaglitazar resulted in changes typical for exaggerated PPARα pharmacology in rodents, such as hepatocellular hypertrophy and hepatocellular carcinoma, but not an increased frequency of hemangiosarcomas. At the highest dose level, there was an increased incidence of sinusoidal dilatation and hemangiomas. No increased endothelial cell (EC) proliferation was detected in vivo, which was confirmed by in vitro administration to ECs. Immunohistochemistry and gene expression analyses indicated increased cellular stress and vascular endothelial growth factor (VEGF) expression in the liver, which may have contributed to the sinusoidal dilatation. A two-fold increase in the level of circulating VEGF was detected in the hamster at all dose levels, whereas no effect on VEGF was observed in patients treated with tesaglitazar. In conclusion, investigations have demonstrated that tesaglitazar does not produce hemangiosarcomas in hamster despite a slight effect on vascular morphology in the liver.

Tumors and hyperplastic lesions in Syrian hamsters following transplacental and neonatal treatment with cigarette smoke condensate

Cigarette smoke condensate (CSC) in olive oil was injected into outbred Syrian hamsters: in adults i.p. on the 10th--14th days of gestation, total dose 1.5--2.5 mg/g b.w.; in 12 to 14-days-old animals s.c., total dose 0.5--1.5 mg/animal. Following 15--25 months of observation benign and malignant neoplasms of various location were found in 2/58 (3.4%) females, treated during pregnancy; in 17/51 (33.3%) of their transplacentally exposed offsprings; in 5/53 (9.4%) of neonatally treated hamsters. In the last two groups females were more affected than males. Most frequently occurred tumors of adrenal glands, pancreas, female sex organs, and liver. No tumors appeared in controls, either untreated or injected with olive oil. In addition, hyperplastic lesions, in particular multiple liver cysts and cholangiomatosis were also observed, mainly in animals exposed transplacentally and as neonates.