A probe by the University of Maryland, Baltimore has led to the retraction of four studies that explored the effect of maternal diabetes on neural tube formation. The university’s internal investigation identified image duplications and other data integrity issues in the studies, according to the retraction notices.
The studies are among a group of 25 papers that data sleuths flagged as having potentially duplicated or manipulated images, The Transmitter reported in June 2025. Since then, sleuths have flagged a total of 44 studies on PubPeer.
This set of retractions “raises red flags about validity” of the entire body of work by the team, says Mary Loeken, associate professor of medicine at Harvard University. “My lab has spent time trying to reproduce data from their lab, and we can’t.”
Peixin Yang, endowed professor of obstetrics, gynecology and reproductive sciences at the University of Maryland, Baltimore, is listed as the corresponding author on all four retracted studies and is the only common author across all 44 flagged studies. Two of the retracted studies are co-authored by both E. Albert Reece and Wei-Bin Shen, professor and associate professor, respectively, in the same department as Yang, and they each co-authored one of the two remaining studies.
The retraction notice for one of the studies, published in 2022 in Communications Biology, states that “The Editors have retracted this article at the recommendation of the University of Maryland, Baltimore (UMB). … The UMB also informed the journal that the investigation committee could not confirm the integrity of the data because not all of the relevant original data was available for inspection during the investigation.” UMB policy states that researchers must retain the original data and all project records for at least three years after submission of the final report or award termination.
The other retractions include a 2015 Biochemical and Biophysical Research Communications study, a 2019 Reproductive Toxicology study and a 2020 Cell Death and Disease study.
Yang, Reece and Shen did not respond to The Transmitter’s requests for comment for the 2025 story. On 3 September 2026, The Transmitter received a letter from Yang’s attorney, Alexa Millinger of Hinckley Allen in Hartford, Connecticut, demanding that The Transmitter’s article be corrected and retracted because it “creates the false impression that Dr. Yang engaged in misconduct, and has caused direct harm to Dr. Yang’s career.” The story’s statement that Robert Cabrera, associate professor of molecular and cellular biology at Baylor College of Medicine, could not replicate Yang’s findings on the benefits of rapamycin was incorrect because Cabrera used a different mouse model than Yang did, the letter states.
The Transmitter responded via email on 14 September with questions about the UMB investigation and the retractions, and requesting an interview with Yang. In a second letter, dated 18 September, Millinger did not reply to a question about whether Yang agreed with the retractions. “We would also respectfully note that the three retraction notices [for the 2019, 2020 and 2022 studies] do not state that Dr. Yang was found to have committed research misconduct,” she wrote in the follow-up letter.
The letter also included email correspondence between Cabrera and Yang, dated 30 July 2025, in which Cabrera confirmed that he and his colleagues “were unable to reproduce a rescue [by rapamycin] in our model, at least in part, because the dosing is developmentally toxic” and cited two other studies that showed rapamycin lethality at the same dose. Millinger wrote that Yang declined to be interviewed by The Transmitter for this story. Cabrera, Reece and Shen did not reply to requests for comment.
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he scope and target of the UMB investigation is unclear. The university denied The Transmitter’s public-records request for copies of the inquiry or investigation report, citing an “ongoing personnel matter.” Millinger also declined to provide the report. It is also unclear which other journals, if any, the UMB contacted.Spokespeople for three journals—Science Signaling, the Journal of Neurochemistry and Developmental Biology—that published flagged papers by Yang and his colleagues told The Transmitter they were not aware of the concerns data sleuths had posted on PubPeer. “This is the first we hear of this,” wrote Ondine Cleaver, editor-in-chief of Developmental Biology, in an email to The Transmitter.
The large number of concerns across so many studies hints at a larger problem, says Elisabeth Bik, a data-integrity consultant who initially raised some of the concerns about the studies by Yang and his colleagues.
Although the retractions represent a positive move in trying to correct the record, there are still studies with problematic figures that have yet to be corrected or retracted, Bik says. “In combination with the university investigation, [journals] did take a pretty hard stance. I think that’s a good outcome.” But it is still incomplete, she adds.
In particular, one 2017 Nature Communications study contains pictures of developing embryos stained for apoptotic cells that seem to have similar elements repeated across the tissue, Bik says. “Clearly, cells are not expected to end up in the same constellations so many times,” she says. “There’s multiple duplications here.” That same study also contains an image of a Western blot that looks similar to a blot used in a previous study showing another protein, Bik adds. “This [study] should be retracted.”
“We are investigating concerns, with support from the Springer Nature Research Integrity team, following an established process and will take editorial action as appropriate,” Stéphane Larochelle, editorial director for biological sciences at the journal, wrote in an email to The Transmitter.
“Some concerns were investigated by journals and found not to warrant retraction, correction, or expression of concern,” Yang’s attorney wrote in her 3 September letter to The Transmitter. The sole example provided in that letter was that the American Journal of Obstetrics and Gynecology concluded that a retraction, correction or expression of concern was not required for a 2013 study after Elsevier’s Research Integrity & Publishing Ethics Centre of Expertise reviewed the concerns and consulted an independent scientist.
Yet in addition to having concerns about duplications, Loeken’s lab has not been able to induce the adverse effects of maternal diabetes in the C57BL/6 mouse strain that Yang’s team uses in their work or reproduce pathways that they see in their model, she says. “In our hands, the same background [on] the same diet is just resistant [to the effects of maternal diabetes],” she says. “When there is questionable methodology and oversight, it calls into question everything that’s come out of their lab.”
