Content area
Full Text
Currently, there is much interest in the value of natural medicinal products, functional foods and "nutriceuticals" to prevent or treat illness. Unfortunately, current evidence of the scientific validity of many of these traditional and commercial compounds is severely limited.
One such product is zinc carnosine (ZnC), which is an artificially produced derivative of carnosine, where zinc and carnosine are linked in a one-to-one ratio to provide a polymeric structure. This product is currently marketed by several companies as a zinc dietary supplement with "added value for gastric health". Combining zinc with carnosine could theoretically provide added benefits over simple zinc supplementation as carnosine is a dipeptide (comprising β-alanine and l -histidine) that is naturally present in long-living cells such as muscle and nerves, where, among other actions, it probably has a role as an antioxidant. 1
To examine further its potential biological actions in a scientific setting, we have performed a series of studies to analyse ZnC in regard to its effects on various mechanisms of gut integrity and repair using well-validated in vitro and in vivo models, and in a clinical trial.
MATERIALS AND METHODS
All chemicals were purchased from Sigma (Poole, Dorset, UK) unless otherwise stated. ZnC was provided by Lonza Nutrition (USA).
Ethics
All animal experiments were approved by local animal ethics committees and covered by the appropriate licences under the Home Office Animals Procedures Acts, 1986. The clinical trial was approved by a local ethics committee and conformed to national requirements.
Study series A: Effect of ZnC on in vitro models of repair
Background to methods
One of the earliest repair responses after injury to tissue is the migration of surviving cells over any denuded area to re-establish epithelial integrity. As it is extremely difficult to study this effect in a human or animal, cell culture models are commonly used as surrogate markers of this pro-migratory response.
Cell migration as a model of wound repair
Cell migration assays were performed using our previously published methods. 2 Two cell lines were assessed: the human colonic carcinoma cell line HT29 and the canine epithelial kidney cell line MDCK.
Cells were grown to confluence in six-well plates in Dulbecco's modified Eagle medium (DMEM) containing 10% fetal calf serum at 37°C in 5% CO2