ATLA 38.2, May 2010

//ATLA 38.2, May 2010

News & Views

ATLA Staff Writer

Human Gene Expression Database Available to Scientists
Nanotechnology and Regulations
Research May Help Dogs and Their Owners
Improvement of Stem Cell Cultures
Human Genetic Studies on Agerelated Macular Degeneration
Toxicity of ZnO Nanoparticles
The Use of Medical Records for Research
Animal Experiment Publication Bias
You need to register (for free) to download this article. Please log in/register here.
2017-01-09T06:38:03+00:00 Tags: |

ECVAM News & Views

ATLA Staff Writer

Progress Toward Regulatory Acceptance
Third International Conference on Alternatives for Developmental Neurotoxicity Testing (DNT)
32nd Meeting of the ECVAM Scientific Advisory Committee
Meeting the Partner Organisations
You need to register (for free) to download this article. Please log in/register here.
2017-01-09T06:38:03+00:00 Tags: |

Prevalidation of the Rat CFU-GM Assay for In Vitro Toxicology Applications

Augusto Pessina, Arianna Bonomi, Loredana Cavicchini, Beatriz Albella, Laura Cerrato, Dominique Parent-Massin, Yann Sibiril, Ralph Parchment, Holger Behrsing, Paolo Verderio, Sara Pizzamiglio, Manuela Giangreco, Carolina Baglio, Valentina Coccè, Francesca Sisto and Laura Gribaldo

In vitro haematotoxicity assays are thought to have the potential to significantly reduce and refine the use of animals for haematotoxicity testing. These assays are used successfully in all types of studies — however, their use is not so common in human toxicology studies in the preclinical setting, as they are not required for regulatory testing in this case. Furthermore, these assays could play a key role in bridging the gap between preclinical toxicology studies in animal models and clinical investigations. In previous studies, the Colony Forming Unit-Granulocyte Macrophage (CFU-GM) assay has been validated for testing drug haematotoxicity (with both mouse bone-marrow and human cord blood) and for predicting the in vivo human maximal tolerated dose (MTD) by adjusting in vivo data on mouse toxicity. Recently, a Colony Forming Unit-Megakaryocyte (CFU-MK) assay has also been prevalidated for testing drug toxicity toward megakaryocytes. The rat CFU-GM assay has been used by many researchers for its ability to evaluate in vitrohaematotoxicity. Although it is not yet available, a standardised procedure for data comparison could be very important, since the rat is the most widely-used species for the in vivo testing of toxicants. This report presents the results of the prevalidation study developed to analyse the intra-laboratory and inter-laboratory variability of a standardised operating procedure for this assay and its performance for the in vitro determination of the inhibitory concentration (IC) values of drugs on rat myeloid progenitors (CFU-GM). The results demonstrate that the CFU-GM assay can be performed with cryopreserved rat bone-marrow cells (rBMC). The assay represents a useful tool for evaluating the toxicity of a compound, in terms of both relative toxicity (when different molecules are compared) and the prediction of the degree of in vivo toxicity. The use of this assay could greatly reduce the number of rats used in experimental procedures, and could also contribute to the accumulation of more toxicity data on compounds to be registered according to the criteria established by the European Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) programme.
You need to register (for free) to download this article. Please log in/register here.

Responses of Human Gingival and Periodontal Fibroblasts to a Low-Zinc Environment

Emil Rudolf and Miroslav Červinka

Morphology, motility, proliferation rate and markers of oxidative stress in primary human gingival fibroblasts (GF) and periodontal ligamental fibroblasts (PDL-F) grown in zinc-deficient cultivation medium (ZDM), were studied over a 5-week culture period. A low-zinc environment effectively reduced the total, as well as the free, intracellular zinc content in both cell types, over the course of the experiment. Decreased intracellular zinc content resulted in altered cellular morphology, reduced motility, and rearrangement of actin and tubulin in the cytoskeleton. In addition, fibroblasts with low zinc content exhibited decreased proliferation, accompanied by changes in cell cycle distribution, expression of specific biochemical markers, increased oxidative stress and the activation of caspase-3. Supplementation of ZDM with exogenous zinc prevented the loss of intracellular zinc, while also restoring the morphology, cell proliferation and mitogenic signalling of the cultured cells. Moreover, such supplemented cells were protected against oxidative stress and cell death. Of the two primary cell cultures examined, GF were more sensitive to decreased intracellular zinc content, when compared to PDL-F. The results obtained suggest that the human primary cell cultures can be useful for the longer-term evaluation of the effects of nutritional factors originating from the environment.
You need to register (for free) to download this article. Please log in/register here.

Further Verification of an In Vitro Tier System for the Identification of Cosmetic Ingredients that are Not Ocular Irritants

Shigenobu Hagino, Yuuko Okazaki, Masato Kitagaki and Hiroshi Itagaki

A tier evaluation system for the identification of cosmetic ingredients that are not ocular irritants was applied to 59 cosmetic ingredients, for which in vivo data were available. The tier system employs monolayer cultures of SIRC cells, an established cell line originally derived from rabbit cornea, and a threedimensional living dermal model (LDM; MATREX™), which consists of human dermal fibroblasts in a contracted collagen lattice. The effects of ingredients on monolayer cultures of SIRC cells were determined by Crystal Violet staining (in the SIRC-CVS assay), and the effects on the LDM were measured by using 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (in the LDM-MTT assay). The classifications of eye irritancy predicted by the in vitro system were compared with previously reported data obtained with the in vivo Draize rabbit eye test. The in vivo classification was based on appearance of corneal damage, or a maximal average score (MAS) of 15 as the cut-off point. The SIRC-CVS assay was effective in the prediction of compounds that would be non-irritants at a concentration of 10%, while the subsequent LDM-MTT assay could predict non-irritancy at various lower and higher concentrations, including 10%. The tier system gave very few false-negative predictions, though false positives were unavoidable. Performing the LDM-MTT assay with an additional 73 ingredients gave similar results in the prediction of non-irritancy at various concentrations. Our findings indicate that the tier system may be suitable for the safety assessment of eye irritancy of ingredients intended to be used in cosmetics and medicated cosmetics in Japan
You need to register (for free) to download this article. Please log in/register here.

Comparing In Vivo, In Vitro and In Silico Methods and Integrated Strategies for Chemical Assessment: Problems and Prospects

Emilio Benfenati, Giuseppina Gini, Sebastian Hoffmann and Robert Luttik

The RAINBOW workshop addressed the background for the integration of in vivo, in vitro and computer-based (in silico) methods, to facilitate the study of the toxic properties of chemicals. On the basis of these discussions, we prepared the present paper, outlining the strengths, weaknesses, opportunities and threats of each approach, both alone and integrated into a single testing strategy. The current scheme for evaluation of chemicals needs to be reshaped, in the face of the much larger numbers of chemicals which need to be examined and the availability of a diversified set of tools.
You need to register (for free) to download this article. Please log in/register here.

A Gold Standard Publication Checklist to Improve the Quality of Animal Studies, to Fully Integrate the Three Rs, and to Make Systematic Reviews More Feasible

Carlijn R. Hooijmans, Marlies Leenaars and Merel Ritskes-Hoitinga

Systematic reviews are generally regarded by professionals in the field of evidence-based medicine as the highest level of medical evidence, and they are already standard practice for clinical studies. However, they are not yet widely used nor undertaken in the field of animal experimentation, even though there is a lot to be gained from the process. Therefore, a gold standard publication checklist (GSPC) for animal studies is presented in this paper. The items on the checklist have been selected on the basis of a literature analysis and the resulting scientific evidence that these factors are decisive in determining the outcome of animal studies. In order to make future systematic reviews and meta-analyses of animal studies possible, to allow others to replicate and build on work previously published, diminish the number of animals needed in animal experimentation (reduction), improve animal welfare (refinement) and, above all, improve the quality of scientific papers on animal experimentation, this publication checklist needs to be used and followed. We have discussed and optimised this GSPC through feedback from interviews with experts in the field of animal experimentation. From these interviews, it became clear that scientists will adopt this GSPC when journals demand it. The GSPC was compared with the current instructions for authors from nine different journals, selected on the basis that they featured a high number of publications on animal studies. In general, the journals’ demands for the description of the animal studies are so limited that it is not possible to repeat the studies, let alone carry out a systematic review. By using the GSPC for animal studies, the quality of scientific papers will be improved. The use of the GSPC and the concomitant improvement in the quality of scientific papers will also contribute to decreased variation and increased standardisation and, as a consequence, a reduction in the numbers of animals used and a more reliable outcome of animal studies. It is of major importance that journal editors become convinced of and adopt these recommendations, because only then will scientists follow these guidelines to the full extent.
You need to register (for free) to download this article. Please log in/register here.