The scientific journal Nature Wednesday retracted two stem cell papers that received national attention when they were published in January.

The paper by researchers from Harvard University and Japan’s RIKEN Institute described a new method of producing versatile stem cells without altering their DNA – a process that promised to make it easier to use stem cells in research and treatment.

Stem cell researchers immediately raised questions about these new cells, called STAP cells, and have tried unsuccessfully for months to reproduce the process of making the cells, as described by the papers.

One author, Teruhiko Wakayama from RIKEN, has been calling since March for a retraction in light of the concerns. The first author, Haruko Obokata, a junior scientist at RIKEN, was accused by her institution in April of scientific misconduct after errors were found in the images, and some of the descriptions in the paper were found to be plagiarized.

Harvard stem cell and tissue engineering biologist Charles Vacanti, who helped lead the research and was the last of the authors to call for a retraction, said Wednesday that he still believes in the existence of STAP cells but can no longer stand behind the papers.

“Although there has been no information that cast doubt on the existence of the stimulus-triggered acquisition of pluripotency (STAP) cell phenomenon itself, I am concerned that the multiple errors that have been identified impair the credibility of the manuscript as a whole,” he said in a prepared statement.

Stem cells have long been seen as the future of medical care, offering the possibility of mending damaged hearts, replacing brain cells lost to Alzheimer’s or repairing paralyzed spinal cords. But that potential has been limited – first by the controversial need to destroy embryos for research, then by the cumbersome and expensive techniques used to make stem cells without embryos.

In the January papers in Nature, researchers showed they could turn mature cells into STAP cells cheaply and easily, essentially by bathing skin or other cells in acid..

If STAP cells worked, researchers could easily make stem cells from a person’s own skin or blood, as therapy for a wide range of ailments.

In theory, a doctor could, say, scrape some cells off the arm of a heart attack patient and turn them into stem cells, which could then become healthy heart cells. Eventually they could be implanted in the heart where they could take over for damaged ones.

Paul Knoepfler, a stem cell researcher at the University of California, Davis, said the incident also shows the growing power of social media in scientific research.

“Social media greatly accelerated the process by which the acid bath claims were tested and the troubles with these papers were revealed,” said Knoepfler, an active science blogger. “You can expect social media more broadly to have an increasingly powerful role in science.”

In the retraction, Nature outlined additional problems with the initial research, making it “clear that data that were an essential part of the authors’ claims had been misrepresented,” according to an editorial published along with the retractions.

The papers’ authors outlined five newly caught errors, including mislabeling of images and photographs that purported to show two different things, but actually showed the same thing.

“We apologize for the mistakes included in the Article and Letter,” they wrote in a statement signed by all the original authors. “These multiple errors impair the credibility of the study as a whole and we are unable to say without doubt whether the STAP-SC phenomenon is real.”

The papers will continue to be available to the public but will carry a notation that they have been retracted, the journal said.

Rudolf Jaenisch, a stem cell biologist at the Massachusetts Institute of Technology, said he thought the retraction was overdue and he was “surprised it took so long.” Although he doubted from the outset that STAP stem cells were real, researchers in his lab had unsuccessfully tried to create them following the protocol laid out in the papers.

“People wasted time, people wasted resources to reproduce this,” he said. “Science is built on trust.”

Intentionally misrepresenting data hurts the credibility of all science, said Ian Chambers, a professor of stem cell biology at the University of Edinburgh in Scotland.

“Events like this undermine public confidence,” he said, adding that he was glad that RIKEN had acted responsibly by launching an investigation into the research. “On the one hand the misconduct is damaging, but the way that the doubt was dealt with is reassuring.”