In vitro assessment of respiratory toxicity: selection of a suitable cell line
With the human lung having more than 60 different cell types and a variety of different cell functions present, the in vitro assessment of respiratory toxicity is a challenging endeavor. Each cell type and the function it performs represents a potential target for a toxic mechanism of action. The first question when selecting a suitable cell line for in vitro studies of respiratory toxicity is therefore which factors are responsible for the susceptibility of the lung and which of these
Toxicological risk assessment (TRA)
A toxicological risk assessment or TRA is a multi-step process that estimates the risk of adverse health events from exposure to leachable substances from a medical device. It encompasses the scientific review and evaluation of all relevant scientific data on the toxicity of, and the exposure to, a certain compound or mixture (Younes, 2014). Components of a toxicological risk assessment are shown in the figure. Toxicological risk assessment services conducted by Medical Matters (MM) highlight possible adverse risks to patients’ health such
Intra- and Inter-assay variability of cytotoxicity testing
The viability of cells in cytotoxicity assays is always calculated relative to untreated control cells that undergo the same seeding and exposure procedure but receive only crude extraction media that has been incubated without the test item. Moreover, the spectrometric signal measured for a specific well in the assay is always corrected by blanks in the assay where the absorption background is measured in wells that received the assay reagent but incubation took place without cell. The variability of the measured absorption
In vitro alternatives for skin sensitization testing of medical devices
Besides cytotoxicity and irritation, sensitization is one of the three biological endpoints that must be evaluated for all medical devices independent of type and duration of their body contact (ISO 10993-1). In contrast to irritation (ISO 10993-23) and cytotoxicity (ISO 10993-5), validated in vitro methods that are qualified and well established in routine use are still lacking for the sensitization endpoint (ISO 10993-11). However, the ISO 10993 series of standards explicitly encourages the use of in vitro methods over the use of
Intralaboratory comparability of cytotoxicity testing conducted according to ISO 10993-5
In vitro cytotoxicity testing is an essential part of the biocompatibility assessment of new materials. However, the ISO 10993-5 standard allows a high degree of variability in the choice of test conditions between individual tests. It is therefore not always possible to directly compare test results between tests without taking the actual test conditions into account. In order to evaluate the effects of the test conditions on the results of the cytotoxicity tests, Jablonská et al. investigated amongst others, different serum concentrations, different media
Interlaboratory comparability of cytotoxicity testing conducted according to ISO 10993-5
The ISO standard for the performance of cytotoxicity assays for medical devices does not explicitly specify the type of cytotoxicity assay to be used and also allows a high degree of freedom in the choice of exact test parameters. This may lead to significant differences in test results among laboratories and depending on the type of test and parameters chosen. An interlaboratory study coordinated by Gruber S. and Nickel A. therefore compared test results of 52 international laboratories for two