Parkinson’s Researcher Fabricated Data
Neuroscientist Mona Thiruchelvam agrees to retract two studies linking neurodegeneration to pesticides.

A former assistant professor at the University of Medicine and Dentistry, New Jersey (UMDNJ) committed research misconduct by fabricating data, according to an investigation by the university and the Department of Health and Human Services’ Office of Research Integrity (ORI). The ORI, which announced its findings on Thursday (June 2icon_cool.gif, determined that Mona Thiruchelvam falsified cell count data published in two papers in 2009 in Environmental Health Perspectives and Journal of Biological Chemistry, both of which she has agreed to retract.

Thiruchelvam fabricated stereological cell count data in two studies on how pesticides influence neuronal mechanisms involved in Parkinson’s disease (PD). The studies reported the results of 13 new experiments that supposedly counted nigrostriatal neurons in the brains of mice and rats, but an investigation spearheaded by the UMDNJ determined those counts were never taken. The nigrostriatal pathway is a major dopamine circuit in the brain, and loss of neurons in this area is one of the main features of Parkinson’s disease.

The papers slated for retraction investigate the neurological response to the combined pesticides paraquat and maneb, and suggest the pesticide atrazine also has a role in disrupting dopamine pathways. The false data were used to create several summary bar graphs, which Thiruchelvam modified to support the hypothesis that proteasomal dysfunction is higher in males than females with PD, and that exposure to paraquat and maneb enhances this effect.

Gary Miller, who cited the Environmental Health Perspectives paper (which has been cited 36 times, according to ISI), said his lab has always been skeptical about the association between certain herbicides and Parkinson’s. “There is strong evidence of an association between pesticides and PD, but figuring out exactly which compounds are driving this has been difficult,” he told The Scientist by email. “I suspect some laboratories have pursued studies based on these findings, which is unfortunate. The retraction of these papers doesn’t help the field.”

Deborah Cory-Slechta, a co-author on the same paper, said in an email she was “both shocked and disappointed” by the news. Both papers have had influence in the field, with the Journal of Biological Chemistry study being cited 73 times according to ISI.

A collaborator at UMDNJ first brought the matter to the attention of university research integrity officials a few years after Thiruchelvam joined the university in 2003, when he realized she was publishing cell density data without using his lab as she had done before. An initial inquiry was launched, for which Thiruchelvam provided the name of a researcher in California who she said had provided her with data. The witness, who Thiruchelvam said by that point had moved to England, was called and confirmed the story, but further investigation by UMDNJ revealed that this was a false witness. When investigators got a hold of the actual person Thiruchelvam had named, they learned she still resided in California and that she denied providing any data to Thiruchelvam.