Rapamycin for Azheimer’s patients?


Easter Island Statue
Rapamycin was first isolated from soil samples taken from Rapa Nui (Easter Island)

Image: Flickr - A.www.viajar24h.com

Two recent reports from the University of Texas Health Science Center suggest that rapamycin may find a new use in treating Alzheimer’s disease (AD). The first study, published in the Journal of Biological Chemistry, showed that treatment with rapamycin reduced AD-like pathology in 3xTg-AD mice and the more recent study, published in PLoS ONE, showed that rapamycin also improved spatial learning and memory in PDAPP transgenic mice, another murine model of AD. Earlier studies had shown that rapamycin, which blocks the mTOR pathway and is used as an immunosuppressant to prevent rejection following organ transplants, can extend the lifespan of mice, even if treatment is started relatively late in life.

In both 3xTg-AD and PDAPP mice, treatment with rapamycin was found to lower levels of amyloid peptide, Aβ42, a hallmark feature of AD which is believed to be a major cause of neurotoxicity. The reduction in Aβ42 when mTOR activity is reduced may be a consequence of induction of autophagy by high levels of Aβ42. The improved performance of PDAPP mice treated with rapamycin appeared to result entirely from enhanced cognitive performance with no effect on emotions such as anxiety.

The authors suggest that, if the results with mice are borne out by studies in people, rapamycin could be used to prevent or treat AD but the potential benefits will need to be carefully weighed against increased susceptibility to infection and the possible development of some types of malignancy which could result from prolonged immunosuppression.

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