This is an EC-funded project (LSHB-CT-2006-037575), coordinated by me, to develop high throughput versions of the comet assay for measuring DNA damage. This 3-year project (2007-2009) had 15 partners – universities, research institutes, a regulatory body, and SMEs. We developed versions of the popular comet assay (single cell gel electrophoresis) to analyse 6-10x as many samples per experiment as with the standard method.
NewGeneris – Newborns and genotoxic exposure risks
Also an EC-funded project (FOOD-CT-2005-016320). Leader of Workpackage 11, on phenotypic markers of DNA damage and repair. Several mother-and-child cohorts in Europe have provided samples of maternal and cord blood, and we have analysed DNA damage and repair in isolated lymphocytes. The overall aim is to look for associations between such biomarkers and maternal exposure to food-borne mutagens and also protective factors.
DNA damage and repair in the human eye
This is a collaboration with Prof. Bjørn Nicolaissen and colleagues in the Ophthalmology Dept, Ullevål sykehus. We have received samples of lens epithelium, and corneal epi- and endothelium. Single cell suspensions are easily obtained, and the comet assay has given clear indications of the levels of oxidative damage to DNA in these cells.
We have set up a collaborative project which has been joined by almost 100 researchers throughout the world who already use the comet assay in human biomonitoring. The aims are: to collate existing published and unpublished data from these researchers; to carry out a ‘pooled analysis’ of these data; to standardise the comet assay; to investigate inter-laboratory variation in results with standard samples; and to set up parallel population studies in different countries to investigate international differences in DNA damage and repair.
Enzyme-linked genotoxicity assay
The comet assay, as used at present in genotoxicity testing, is excellent at identifying chemicals that cause DNA strand breaks, but many agents cause base damage without breaking the phosphodiester chain. We have found in preliminary experiments that including enzymes such as formamidopyrimidine DNA glycosylase (FPG) in the assay greatly increases its sensitivity. By systematic testing of recognised genotoxins, negative controls, and chemicals that are known to give ambiguous results, we are assessing the value of this modification of the assay in comparison with other, established, genotoxicity assays.
With support from Inven2 and NILU, we recently set up a spin-off company, Comet BioTech, to apply the comet assay and other DNA damage and mutation assays to the testing of chemicals for genotoxicity, and to investigating the effects of mutagens (and protective factors) on human populations and the natural environment.