Findings announced in December on a model of Alzheimer'sdisease have been retracted by the study's authors.

Scientists at Mount Sinai Medical Center in New York,collaborating with Yamanouchi Pharmaceutical Co. of Tokyo andthe National Institutes of Health, had published in Nature thatthey had created a transgenic mouse model of the disease.

The mice supposedly had shown degenerative changes thatmore closely mimic the neuronal changes of the human disease,compared to other models. But the histopathology, originallydone at the NIH, could not be reproduced, said the authors in ayet-unpublished letter to the journal.

The mice were given a gene that makes a portion of theamyloid precursor protein (APP). This transgenic aspect of theexperiments was verifiable, in that overexpression of the C-100fragment of the human APP gene occurred.

But a repeat experiment failed to show development of theamyloid plaques, neurofibrillary tangles and cell losscharacteristic of the advanced human disease originallyreported in the Dec. 12 issue.

"While further evaluation is ongoing, at the present time webelieve it is prudent to retract these histopathologic findings,"the scientists wrote. "As for the conclusion of the paper, thatour transgenic animals constitute a useful rodent model ofAlzheimer's disease, that issue remains to be assessed byfurther study."

The letter has yet to appear in Nature, but both Mount Sinaiand the NIH have released statements.

The NIH said that "to resolve the questions raised by thescientific community regarding the findings reported in Nature,the National Institute on Aging has requested that the Office ofIntramural Research ... appoint a committee to look into thematter."

"This in an informal inquiry," said NIH spokeswoman JaneShure.

Other animal models exist. Scios Inc., formerly CaliforniaBiotechnology Inc., of Mountain View, Calif., and Miles ResearchCenter of West Haven, Conn., have colonies of mice thattransmit and express the human gene for APP and betaamyloid, respectively. -- Roberta Friedman, Ph.D.

(c) 1997 American Health Consultants. All rights reserved.