Microbes implicated in heart disease
Last year, a research team offered some of the first molecular
evidence to support the provocative idea that heart disease
could stem from infections with bacteria that cause chlamydia.
Now, the group suggests that other microbes might cause heart
problems in the same way.
In the earlier work, Josef M. Penninger of the University of
Toronto and his colleagues discovered that part of a protein
made by chlamydia bacteria resembles a piece of a protein in hu-
man heart tissue. Injecting mice with the bacterial protein pro-
duces an immune reaction against their own hearts and blood
vessels. While the illness seen in the animals isn't the same as
atherosclerosis, Penninger suggested that an immune response
against the microbes' heartlike protein might still explain the evi-
dence linking chlamydia infections to human heart disease.
Yet many people with heart disease don't possess the anti-
bodies that would indicate a past chlamydia infection. Penninger
and colleagues now report in the August NATURE MEDICINE that
bacteria, viruses, and other microbes make the protein bit
shared by the human heart and chlamydia bacteria. The re-
searchers isolated the protein bit from nine different microbes,
and in five cases used it to stimulate a heart-directed immune at-
tack in mice. "Chlamydia [bacteria] may just be the beginning of
the story," suggests Penninger. -11: