Paolo Macchiarini

Paolo Macchiarini

ITAR-TASS Photo Agency/Alamy Stock Photo

Panel finds misconduct in rat paper by star surgeon Paolo Macchiarini

Scandal-plagued surgeon Paolo Macchiarini, famous for implanting tissue-engineered tracheae into patients, committed misconduct when he and his co-authors published misleading results in a 2014 paper, Sweden’s Central Ethical Review Board (CEPN) said today. In a paper in Nature Communications describing implants of a tissue-engineered esophagus into rats, the authors claimed positive results that were inconsistent with their lab records, the panel said in its paper.

Today’s report is the first of four assessments that the Karolinska Institute (KI) requested from CEPN involving a half-dozen papers co-authored by Macchiarini. It has been submitted to KI’s interim vice-chancellor Karin Dahlman-Wright, who has the final authority to rule whether Macchiarini and his colleagues committed misconduct.

Macchiarini implanted his artificial tracheae, seeded with a patient’s own stem cells, into people with damaged or missing tracheae in Spain, the United Kingdom, Sweden, the United States, and Russia. Three patients received implants at the Karolinska University Hospital while Macchiarini was a visiting professor at KI. Two of them died, and a third has been in intensive care since the implant operation in 2012. Colleagues at the hospital raised questions about Macchiarini’s work in 2014, triggering an ongoing scandal that this week prompted the dismissal of Sweden’s top higher education official and the entire board of KI.

An earlier investigation into the papers found evidence of misconduct, but it was dismissed by vice-chancellor Anders Hamsten. Following a television documentary that examined Macchiarini’s work in Sweden and Russia, KI reopened the investigation. (In the wake of the growing scandal, Hamsten stepped down as chancellor in February.)

Today’s statement by CEPN’s expert group for misconduct in research—which investigates misconduct allegations at the request of Swedish universities—is about a 2014 paper in which Macchiarini and his colleagues gave rats an esophagus implant made from a donor esophagus that had been stripped of its cells and “seeded” with stem cells. (Macchiarini tried the same technique on some of his human trachea patients.)

The panel asked the authors to hand over the data to back up their conclusions, but despite “repeated and clearly defined requests,” it received “incomplete and sporadically incorrect data.” Not providing complete data to support a paper—or being unable to provide it—constitutes misconduct in itself, the panel says. But the paper also presents misleading and incorrect data and conclusions. Although the paper concludes that the implants were successful, the data the panel recovered told a different story, the expert group writes. They found that “the rats lost so much weight and deteriorated so much in condition that the experiment should have been stopped.”

The panel says that, as corresponding author, Macchiarini is primarily responsible for the article content and is therefore guilty of misconduct. His co-authors also bear responsibility, the panel says, although it “has some degree of understanding” for more junior authors who were dependent on Macchiarini and other leaders of the research group. It notes that at the time the paper was published, Macchiarini had “significant support from the management” of KI. Neither Macchiarini nor co-author Philipp Jungebluth, who is singled out in the statement as playing a “key role in the research process,” responded to Science's request for comment.

Although questions about the paper’s accuracy have circulated for more than a year, Nature Communications has not taken any public steps toward retraction, nor flagged the paper as potentially suspect for its online readers. A spokesperson for Nature Communications said the journal is “following established process to investigate the issues” in the paper.

CEPN is expected to issue its second statement, involving Macchiarini’s papers that describe the results of the human implants, next week. The final two statements are expected in late autumn.