The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Abstract for TestSmart--A Humane and Efficient Approach to Screening Information Data Sets (SIDS) Data

Use of Alternative Tests in the Screening Information Data Sets (SIDS) Battery

Sidney Green1, Alan M. Goldberg2 and Joanne Zurlo2
1Howard University, Washington, D.C.; 2Johns Hopkins Center for Alternatives to Animal Testing, Baltimore, MD

The Johns Hopkins Center for Alternatives to Animal Testing (CAAT) is coordinating an effort to examine the current status of alternative methods for Screening Information Data Sets (SIDS) endpoints and to make recommendations about the use of these methods in the HPV Challenge Program. This effort, "TestSmart", is part of a grant awarded to the Environmental Defense Fund by the Heinz Foundation that includes the University of Pittsburgh, and Carnegie-Mellon University in addition to the Johns Hopkins University. The emphasis with respect to alternatives has been on those endpoints associated with mammalian toxicity. An assessment of the "state of readiness" of the recommended alternatives has also been made preliminarily. Alternatives are defined by the 3Rs of Russell and Burch: replacement, refinement and reduction of animal use.

Recommendations for acute toxicity testing (LD50) are for use of the up and down, the fixed-dose, the acute toxic class and the limit test as alternatives to the classical LD50 as currently accepted by the OECD. These methods are reduction and refinement alternatives to the classical LD50. Cell culture methods such as basal cytotoxicity and neutral red uptake have also been recommended. It is thought that the non-culture methods can be used immediately, whereas the cell culture methods are in need of validational work particularly in the area of metabolic activation.

If emphasis is placed on morbidity, moribundity and cause of death as the endpoints in acute toxicity testing, rather than the LD50 , then target organ toxicity becomes the central focus. Cell cultures of major organ systems could provide some information, such as cultures of liver, vascular, cardiac, respiratory, CNS (autonomic), kidney could be useful. These are in the research/developmental stage and require a considerable amount of work before they can be used as alternatives for acute non-LD50 endpoints.

For repeat dose toxicity, 90 or 28 day, there are few if any replacement alternatives. Reduction strategies appear to be the better approach. However, modeling of repeated exposure using cell cultures of major organs could be undertaken. Organs of interest would be the same as those listed for acute toxicity testing. Research and development need to be undertaken in this area.

In the case of genetic toxicity, there are available a number of alternative methods to the animal procedures; the Ames test for bacterial gene mutation, the mouse lymphoma for mammalian cell gene mutation, the Chinese Hamster Ovary for mammalian cell chromosomal mutations. Development and validation of the in vitro micronucleus would lead to another mammalian method for chromosomal mutations. The Syrian Hamster Embryo assay for transformation could be added to these tests to provide some information as to carcinogenic potential.

For developmental toxicity, FETAX, embryonic stem cells and the Zebra fish assay are undergoing validation currently. Several cell culture methods hold potential and are in need of validational work as well. These methods are the whole embryo and limb bud culture techniques. It has also been recognized that gene chip technology, (analysis of receptors, gene activators, enzymes), could contribute in terms of mechanisms of developmental toxicity. This technology is in the research stage of development.

The most difficult toxicity endpoint in terms of alternatives is that of reproduction. Other than sperm motility and morphology; all other methods are in the research/developmental stage. Sertoli cell lines, sperm penetration, culture of primary follicles fall in this category. Receptor binding assay are in use currently, but would need validational work before use as alternatives.

TEST SMART, a humane and efficient approach to regulatory toxicology issues provides a case study; for the implementation of the 3Rs of alternatives.