Scientists have discovered a clue as to why some children survived the
melamine-contaminated milk scandal in China.
In 2008, nearly 300,000 Chinese
children were hospitalized with kidney problems after ingesting powdered milk
that had been deliberately contaminated with melamine. Six babies eventually
died from kidney damage.
Melamine, rich in nitrogen and a
component of a type of plastic, had been added to the powdered milk to boost
the apparent protein content. Melamine was found to combine with uric acid in
the children’s bodies to produce harmful kidney stones. However, why some
children were more badly affected than others was a mystery.
In a study led by Prof. Wei Jia
at the University of North Carolina in collaboration with scientists from
Shanghai Jiao Tong University and Imperial College London, the scientists
examined melamine-induced kidney stone formation in rats to understand the
development of disease and the role that gut microbes could play in this
process.
The team first fed rats
antibiotics to kill off selected microbial populations in the gut, then fed the
rats melamine. Rats treated with antibiotics had fewer kidney stones and were
less affected by the melamine.
They were found to excrete double
the amount of melamine than rats that did not receive antibiotic treatment.
Publishing their results in the
journal Science
Translational Medicine, the team report that certain species of gut
microbes are responsible for converting melamine into cyanuric acid. This then
accelerates the rate at which kidney stones are formed.
Microbes of the Klebsiella family
tend to facilitate the process of melamine conversion, potentially making them
key players in the formation of kidney stones. The scientists believe that the
make-up of gut microbes in the poisoned animal or person affects the eventual
outcome.
According to Prof. Nicholson from
Imperial College London and co-author of the study:
“The metabolic activities of gut
microbes strongly influence human health in profound ways and have been linked
to the development of multiple medical problems ranging from autoimmune
diseases, obesity, diabetes, and cardiovascular disease.”
“The specific implication of this
research is that the expression of the kidney disease in the Chinese
contaminated milk scandal is likely to have been mediated by gut bacteria in
affected children. The more general implication is that gut microbial status
affects the outcome to exposures to environmental and food contaminants.”
The article can be found
at: Zheng X et al. (2013)
Melamine-Induced Renal Toxicity Is Mediated by the Gut Microbiota.
Source: Imperial
College London;
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