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expert reaction to triclosan and heart muscle damage

An antibacterial agent, called triclosan, was found to hamper muscle function in animals and fish in a study published in the Proceedings of the National Academy of Sciences.

 

Prof Tony Dayan, Emeritus Professor of Toxicology, University of London, said:

“Whilst this research is of interest to scientists, it would be totally wrong to extrapolate to humans or wider environmental concerns because these experts were working with extremely high levels of triclosan.

“The authors report a sophisticated study of electrophysiological and ion flux across membranes. The effects they demonstrate under their experimental conditions are very likely to be correct and valid – for their experiment – which is the key point.

“Almost all their work is based on huge doses of triclosan given directly into the body, i.e. intraperitoneal injection, or into the test system in vitro. The concentrations will be far in excess of anything ever achieved in humans or animals that are exposed to triclosan by the conventional routes of oral or dermal exposure, such as from toothpaste, deodorants, socks, nappies etc.

“For example, the researchers gave 12.5mg/kg IP to mice. Absorption would be complete. Whilst they did not cite the blood levels produced, I would expect several μM. In contrast, humans using 0.3% dentifrice three times per day for 15 days had blood levels of 250-450ng/mL (equal to just 0.01-0.02μM).

“Furthermore, many studies of triclosan in mice, including carcinogenicity studies involving daily exposure for more than 78 weeks, and in rats for 2 years at doses up to 100mg/kg/day produced blood levels in low μM range with no clinical or histological evidence of cardiac or other muscle damage.

“In summary, the results found here depend on concentrations 50- to several hundredfold greater than those which were shown to have no harm to muscles of humans or lab animals.

“As with any chemical that is present in the environment, and which may occur in milk including human breast milk, questions will deservedly be asked about the possibility of any effect on development. No risk to man has been identified with triclosan but the scientific community must stay alert and monitor for any effects just in case.”

‘Triclosan impairs excitation–contraction coupling and Ca2+ dynamics in striated muscle’ by Cherednichenko et al., published in PNAS on Monday 13th August.

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