Hong Kong Med J 2013;19(Suppl 8):S34-8
Impact of melamine-tainted milk on foetal kidneys and disease development later in life
H El-Nezami, PKH Tam, Y Chan, ASY Lau, FCC Leung, SF Chen, LCL Lan, MF Wang
School of Biological Sciences, The University of Hong Kong
1. Melamine has very low cytotoxicity on kidney cells of a susceptible species (canine), and the presence of its main degradation product cyanuric acid did not influence its cytotoxicity. This indicates that the toxicity of melamine is mainly due to the formation of kidney stones rather than a direct toxic effect on kidney cells.
2. Ingestion of melamine alone failed to induce kidney stones even under conditions of restricted drinking water access. In mice administrated with melamine together with cyanuric acid, no renal stones were formed when the supply of drinking water was unrestricted. However, when drinking water was limited, stone formation was observed.
3. Melamine was detected in the foetal circulation of perfused human placenta and easily transferred through it. The presence of cyanuric acid did not influence the transfer of melamine from the maternal to the foetal side.
4. Administration of melamine and cyanuric acid to pregnant mice did not cause any noticeable develop- mental or reproductive abnormalities.
5. No melamine crystals were detected in kidneys of the embryos or breastfed pubs, despite the mothers having melamine crystals in their kidneys and renal failure.