A natural defense mechanism that the body deploys to combat nerve cell degeneration observed in persons with Alzheimer's disease (AD) has been discovered by a team from the Faculty of Medicine at Université Laval and the research centre at CHUQ (Centre hospitalier universitaire de Québec).

The Investigators Alain R. Simard, Denis Soulet, Genevieve Gowing, Jean-Pierre Julien and Serge Rivest described this major discovery in the February 16th issue of the scientific journal Neuron.

Alzheimer's disease is characterized by the accumulation of amyloid proteins in the brain. These proteins form plaques around which microglia, the central nervous system's immune cells, aggregate. These microglia appear to be incapable of eliminating the plaques, and this has led some researchers to postulate that microglial action produces an inflammation causing neuronal death.

For Serge Rivest and his team, whose research is funded by the Canadian Institutes of Health Research (CIHR), microglia are not part of the problem, but of its solution. These investigators have observed that, although the brain's resident microglia do appear to be poorly equipped for combating amyloid plaques, an entirely different case prevails for another type of microglia: those derived from bone marrow stem cells.

The tests conducted with transgenic mouse models of AD showed that bone marrow-derived microglia infiltrate amyloid plaques and succeed in destroying them most efficiently. These newly-recruited immune cells are specifically attracted by the amyloid proteins that are the most toxic to nerve cells. This discovery is an important step towards a new therapeutic approach to Alzheimer's disease.

Source: [Canadian Institutes of Health Research]