Artificial windpipe pioneer and leading stem cell scientist cleared of misconduct charges

Written by Alexandra Thompson

A leading stem cell scientist accused of scientific misconduct by colleagues has been cleared by his institute, after being found guilty earlier in the year by independent investigators

Earlier in the year Paolo Macchiarini was found guilty of misconduct in a preliminary investigation by independent investigators, after accusations by four physicians at the institute. However, after performing their own investigation, the Karolinska Institute has rejected this conclusion, finding the regenerative medicine researcher and artificial windpipe pioneer not guilty of scientific misconduct, although it concluded he sometimes acted without due care.

Macchiarini and colleagues had developed a method of seeding either donated or synthetic wind pipes with patients’ own stem cells for transplantation. He had operated on patients at Karolinska University Hospital, removing diseased or damaged windpipes and implanting replacements made of plastic and treated with stem cells and drugs to encourage the growth of new tissue. Two of the patients eventually died and another has been hospitalized since the operation took place more than 3 years ago. Following inquiry, in May the independent investigators concluded that the resulting scientific papers included misrepresented data that made the trachea transplants appear more successful than they actually were.

In response, Macchiarini and his co-authors submitted more than 1000 pages of documents to the Karolinska Institute, where Macchiarini is a visiting professor, for its own investigation. Anders Hamsten, the author of the latest report and Karolinska vice chancellor, stated on the 28th August that the work in question “does not meet the university’s high quality standards”, but did not find misconduct — overturning the claims of the previous report. He acknowledged that Macchiarini’s work was flawed, “but nothing that can be considered scientific misconduct.” The latest report therefore commented that “the submission of an erratum could therefore be appropriate”.

Macchiarini has been instructed to submit corrected information to the journals that published some of his work to clarify the mistakes highlighted by the university’s inquiry. “To have been falsely accused of serious misconduct is every researcher’s nightmare,” Macchiarini stated in an email. He claimed the accusations were extremely damaging to him and the field of regenerative medicine, which resulted in his grants from the Swedish Research Council being frozen in June. Macchiarini said he would be speaking with Karolinska about getting his grants reinstated.

“I feel it is extremely important that public confidence is restored in this field now,” he said. “It is only through the trust of present patients willing to take part in experimental surgeries that patients of the future will have a chance to benefit.”