New investigations into the genotoxicity of cobalt compounds and their impact on overall assessment of genotoxic risk.

The genotoxicity of cobalt metal and cobalt compounds has been widely studied. Several publications show induction of chromosomal aberrations, micronuclei or DNA damage in mammalian cells in vitro in the absence of S9. Mixed results were seen in gene mutation studies in bacteria and mammalian cells in vitro, and in chromosomal aberration or micronucleus assays in vivo. To resolve these inconsistencies, new studies were performed with soluble and poorly soluble cobalt compounds according to OECD-recommended protocols. Induction of chromosomal damage was confirmed in vitro, but data suggest this may be due to oxidative stress. No biologically significant mutagenic responses were obtained in bacteria, Tk(+/-) or Hprt mutation tests. Negative results were also obtained for chromosomal aberrations (in bone marrow and spermatogonia) and micronuclei at maximum tolerated doses in vivo. Poorly soluble cobalt compounds do not appear to be genotoxic. Soluble compounds do induce some DNA and chromosomal damage in vitro, probably due to reactive oxygen. The absence of chromosome damage in robust GLP studies in vivo suggests that effective protective processes are sufficient to prevent oxidative DNA damage in whole mammals. Overall, there is no evidence of genetic toxicity with relevance for humans of cobalt substances and cobalt metal.

Safety evaluation of a whey protein fraction containing a concentrated amount of naturally occurring TGF-ß2.

TM0601p is a whey protein isolate derived from cow milk, containing a concentrated amount of transforming growth factor ß2 (TGF-ß2), and is intended for nutritional use in infants and adults. In vivo and in vitro studies have been performed to evaluate the safety of this product. In a 13-week toxicity study, treatment of adult Sprague-Dawley rats by gavage at up to 2000mg/kg/day did not result in any significant findings other than minor non-adverse changes in urinary parameters in females. The no-observed-adverse-effect level (NOAEL) was established as 2000mg/kg/day. In a juvenile toxicity study, rat pups received 600mg/kg/day by gavage from postnatal day (PND) 7 to PND 49. Transient lower bodyweight gain in the pre-weaning period was attributed to gastrointestinal effects of the viscous test material; following weaning, bodyweight gain was comparable to the vehicle controls. Reduced eosinophil counts and changes in urinary parameters (females) were recorded in treated pups at PND 49, and higher thymus weights were recorded in males only at the end of the recovery period (Day 77). None of the findings were considered adverse. There were no other significant findings and the NOAEL was established as 600mg/kg/day. No evidence of genotoxicity was seen in the bacterial reverse mutation test or the in vitro micronucleus test. Overall the results obtained present a reassuring safety profile for TM0601p.