Reproducing human and cross-species drug toxicities using a Liver-Chip

Nonclinical rodent and nonrodent toxicity models used to support clinical trials of candidate drugs may produce discordant results or fail to predict complications in humans, contributing to drug failures in the clinic. Here, we applied microengineered Organs-on-Chips technology to design a rat, dog, and human Liver-Chip containing species-specific primary hepatocytes interfaced with liver sinusoidal endothelial cells, with or without Kupffer cells and hepatic stellate cells, cultured under physiological fluid flow. The Liver-Chip detected diverse phenotypes of liver toxicity, including hepatocellular injury, steatosis, cholestasis, and fibrosis, and species-specific toxicities when treated with tool compounds. A multispecies Liver-Chip may provide a useful platform for prediction of liver toxicity and inform human relevance of liver toxicities detected in animal studies to better determine safety and human risk.

The c-Met Tyrosine Kinase Inhibitor JNJ-38877605 Causes Renal Toxicity through Species-Specific Insoluble Metabolite Formation

PURPOSE

The receptor tyrosine kinase c-Met plays an important role in tumorigenesis and is a novel target for anticancer treatment. This phase I, first-in-human trial, explored safety, pharmacokinetics, pharmacodynamics, and initial antitumor activity of JNJ-38877605, a potent and selective c-Met inhibitor.

EXPERIMENTAL DESIGN

We performed a phase I dose-escalation study according to the standard 3+3 design.

RESULTS

Even at subtherapeutic doses, mild though recurrent renal toxicity was observed in virtually all patients. Renal toxicity had not been observed in preclinical studies in rats and dogs. Additional preclinical studies pointed toward the rabbit as a suitable toxicology model, as the formation of the M10 metabolite of JNJ-38877605 specifically occurred in rabbits and humans. Additional toxicology studies in rabbits clearly demonstrated that JNJ-38877605 induced species-specific renal toxicity. Histopathological evaluation in rabbits revealed renal crystal formation with degenerative and inflammatory changes. Identification of the components of these renal crystals revealed M1/3 and M5/6 metabolites. Accordingly, it was found that humans and rabbits showed significantly increased systemic exposure to these metabolites relative to other species. These main culprit insoluble metabolites were generated by aldehyde oxidase activity. Alternative dosing schedules of JNJ-3877605 and concomitant probenecid administration in rabbits failed to prevent renal toxicity at dose levels that could be pharmacologically active.

CONCLUSIONS

Combined clinical and correlative preclinical studies suggest that renal toxicity of JNJ-38877605 is caused by the formation of species-specific insoluble metabolites. These observations preclude further clinical development of JNJ-38877605.

IGF-I enhances survival of embryonic chick ciliary ganglion neurons in a calcium-dependent way

We have shown that neurons from embryonic chick ciliary ganglia in primary culture possess receptors for insulin-like growth factor I (IGF-I). When added to serum- and insulin-free culture medium, the factor potently enhanced neuronal survival as observed after 24 and 48 h of culture. The effect saturated at 5 ng/ml. Laminin was not necessary for the trophic effects of IGF-I; in the absence of the factor, it had no effect on neuronal survival. Insulin exerted a trophic effect similar to that observed with IGF-I, but at higher doses. The trophic effect of IGF-I was sharply and specifically reduced when either a membrane-permeable calcium chelating agent or blockers of voltage-dependent calcium channels were added to the medium.

Immunohistochemistry for light microscopy in safety evaluation of therapeutic agents: an overview

The history of immunohistochemistry started in 1941 when Coons identified pneumococci using a direct fluorescent method. Then followed the indirect method, the addition of horseradish peroxidase, the peroxidase anti-peroxidase technique of 1979 and the use of the Avidin and Biotin complex in the early 1980s. This sequence of events can help one appreciate the differences in these various techniques and their increased sophistication and sensitivity. The technique has been applied in the field of safety evaluation of new pharmaceutical products. Examples of current projects are used to illustrate the scope of the application. The use of an antibody to detect proliferating cell nuclear antigen has, in a pilot study with the popliteal lymph node assay, provided a method of differentiating an irritant response to acetone from an immune response to hydrazine. In hydrazine-treated rats the proliferation is mainly in the follicular region whilst it is mainly sinusoidal in animals treated with acetone. In the guinea-pig maximisation test, initial work with dinitrochlorobenzene suggests that detection of Langerhans cells may aid the differentiation of an irritant from an immune response. The preclinical assessment of antibodies intended for therapeutic use in man requires immunohistochemistry to be used to identify any human tissues which show a cross-reactivity. The major problems are not in the test itself but in obtaining suitable material. Identification of hormones is a useful tool for assessing the effects of releasing factors and has proved useful in aiding tumour identification in routine carcinogenicity studies. In a rare case, detection of prolactin in cell deposits in the lungs of a rat confirmed that this was a metastasis from a pituitary carcinoma. The application of immunohistochemical techniques to preclinical assessment of drugs should always be considered. In particular, it is recommended that appropriate samples should be conserved from routine studies in order to permit these techniques to be performed, if considered appropriate in the light of findings during routine histological examination.

Immunohistochemical investigation of gamma-aminobutyric acid ontogeny and transient expression in the central nervous system of Xenopus laevis tadpoles

The ontogeny of the gamma-aminobutyric acid (GABA)-positive neurons in the brain of Xenopus laevis tadpoles was investigated by means of immunohistochemistry, using specific antibodies both against GABA and its biosynthetic enzyme, glutamate decarboxylase (GAD). The results obtained with the two antisera were comparable. The GABA system differentiates very early during development. At stages 35/36, numerous GABA-positive neurons were seen throughout the prosencephalon and formed two main bilateral clusters within the lateral walls of the forebrain that ran caudally toward the hindbrain. Other GABA-immunolabeled cell bodies, together with a conspicuous network of GABAergic fibers, were seen in the posterior hypothalamus. In the spinal cord, the lateral marginal zone was GABA-positive, as were Rohon-Beard neurons, interneurons, and Kolmer-Agdhur cells. A very rich GABA innervation was observed in the pars intermedia of the pituitary. At stage 50, plentiful immunopositive neurons and fibers were found in the telencephalic hemispheres, the diencephalon, and the mesencephalon (optic tectum and tegmentum). By stage 54, the number of GABA-immunoreactive neurons in the posterior hypothalamus had decreased, so that, at stage 58, there were very few GABA-labeled cell bodies in the dorsolateral walls of the infundibulum, despite a strong GABAergic innervation within the median eminence and the pars intermedia. From stage 58 to stage 66, the distribution pattern was very similar to that described in the adult X. laevis and in other amphibian species. These results point to transient GABA expression within the hypothalamus, possibly related to either 1) a naturally occurring cell death or 2) a phenotypic switch.

Aminophylline treatment of preterm labor

Prevention of neonatal mortality linked to prematurity may be achieved by treating preterm labor, thus allowing fetal lungs to spontaneously develop, or by administering drugs able to enhance pulmonary maturation. The methylxantine derivative aminophylline has been reported to reduce uterine contractility and increase the concentrations of saturated phosphatidylcholine in fetal lungs. Its effectiveness in treating preterm labor and preventing respiratory distress syndrome (RDS) has been evaluated in comparison to the widely used drug ritodrine. In 39 pregnant women with preterm labor the efficacy of aminophylline and ritodrine in delaying the delivery seemed similar. However, while two of the babies born from ritodrine treated mothers died because of RDS, all babies born from aminophylline-treated mothers survived. These data might then confirm the effectiveness of aminophylline treatment to prevent RDS.