Dipak Kumar Das (1946-2013) who faked data about resveratrol – the magic red wine ingredient that cures everything?

Overview

Dipak Das was a professor and leading cardiovascular researcher at the University of Connecticut Health Center in Farmington, in the USA. Much of his later published work was related to the health benefits of natural products including resveratrol, a compound found in grape-skins, peanuts and some berries. Many of the speculative health benefits of red wine consumption have been attributed to resveratrol although the very small amounts found in most red wines make this a doubtful proposition. In January 2012, the University of Connecticut announced that a three year investigation had found Das guilty of 145 counts of fabrication and falsification of data and that it had frozen all research grants related to Das and declined very substantial sums that were yet to be received. It had also notified 11 journals which had published his work about these accusations and had begun dismissal proceedings against him. Das began proceedings for defamation against the University and was asking for $35million in damages but died on 19th September 2013 before this case was resolved.

Career achievements and influence

Dipak Das trained as a biochemist at Jadavpur University in Kolkata, India and moved to the USA in 1971. He gained a PhD from New York University and in 1982 he joined the faculty of the University of Connecticut where he remained until his dismissal in 2012. He rose within the University of Connecticut to become director of the Cardiovascular Research Center at Farmington. An online biography credits him with publishing over 500 peer reviewed publications, over 100 review articles and book chapters and fifteen books. The PubMed database lists 672 publications for “Das DK” and the Scopus database lists 479 documents that can confidently be attributed to this particular Das. According to Scopus these Das publications were cited 13,566 times by other authors; he was producing some papers that had respectable citation rates but none were highly influential citation classics.

Das was editor in chief of the journal Antioxidant and Redox Signalling and he is said to have played a role in establishing the journal as one of its founding editors; two of his retracted papers were published in this journal. Once accusations of research fraud were made, he was dismissed as editor and his name was removed from the journal masthead. In an editorial announcing the dismissal of Das, his co-editor Dr Chandan Sen sought to play down the influence that Das had had on the journal. His death was announced in the journal in 2013 in a one line statement in which the editor-in-chief and publishers merely note the passing of one of its founding editors. He was said to have served as an associate editor of the prestigious American Journal of Physiology: Heart and Circulatory Physiology in which four of his retracted papers were published. He was also a consulting editor for the journal Cellular and Molecular Biochemistry where he co-authored up to 20 publications.

There is no doubt that Das attracted substantial grant funding during his time at the University of Connecticut; in its announcement of January 2012 the University said that it had declined to accept an additional $890,000 in funding from the US National Institute of Health, NIH. He received several awards from the NIH and from other sources including the American Heart Association and Hungarian government agencies.

Latterly, Das focused on the cardio-protective effect of natural products especially a substance called resveratrol which is found in grape skins and red wine and also substances called tocotrienols found in palm oil. His work suggested that these substances not only reduced the likelihood of a heart attack but, if present before a heart attack occurred, also reduced the subsequent oxidative damage to heart muscle. If resveratrol was administered to animals before an experimentally induced heart attack, he argued that this reduced the subsequent damage and improved the chances of surviving the heart attack. In an experimental heart attack, Das argued that much of the damage occurred when blood flow was restored after a period of occlusion i.e. was caused by so-called re-perfusion injury. This re-perfusion, he argued, generated many damaging oxygen free radicals and this damage could be reduced by an antioxidant such as resveratrol. There are 60 publications by Das related to resveratrol and 10 relating to tocotrienols listed on PubMed and others claiming that other natural products like garlic, broccoli, marigold extract and yam could have similar cardio-protective effects.

The resveratrol story

There is no doubt that there has been considerable interest and controversy about the potential of resveratrol to treat or prevent a variety of diseases and also perhaps to slow the ageing process and extend life expectancy. The growth in scientific interest in resveratrol can be illustrated by figure 1 below which shows the great increase over the last 20 years in the number of publications relating to resveratrol.

resveratrol timeline

On a web-site of a company that produces a resveratrol-based product, Longevinex, Das was quoted by Bill Sardi as suggesting that this resveratrol-based supplement might replace aspirin as the most widely used heart protecting therapeutic agent. A PubMed search using the term Longevinex produced 10 hits and 6 of these listed Das as a co-author. An even more optimistic view of the potential of this supplement is summed up by quotes from Longevinex spokesman Bill Sardi later in this case-study.

Resveratrol serves as an antibacterial or antifungal agent in grapes. Das focused mainly focused on its potential protective effects upon the heart. He claimed that it reduced not only risk of a heart attack but also because of its antioxidant effects reduced the damage caused by a heart attack . Professor David Sinclair of Harvard University is probably the most high profile researcher in the resveratrol field. He suggested that resveratrol increased the production of an enzyme known as Sirt1. These Sirt enzymes remove acetyl groups from proteins and thus regulate their functions. The precise role of Sirt1 in humans is still being debated but the enzyme’s activity has been shown to be low in insulin resistant animals (type 2 diabetics) and high in mice whose lifespan has been increased by calorie restriction. Calorie restriction is regarded as an established way of increasing the lifespan of mice and so the observation that resveratrol seems to mimic one of the effects of calorie restriction led to it being dubbed as a potential anti-ageing pill.

In 2004, David Sinclair co-founded a biotechnology company Sirtris Pharmaceuticals whose focus was on potential drugs, including resveratrol, that might activate Sirt enzymes and thus have potential for treating diabetes, cancer and perhaps even slowing the ageing process. In 2008, this company was purchased by the pharmaceutical giant Glaxo Smith Kline (GSK) for $720million. They were probably attracted by the potential of compounds like resveratrol as potential anti-diabetic drugs. There has since then been an ongoing and sometimes acrimonious debate about the therapeutic potential of resveratrol. The complex issues of what exactly resveratrol does and does not do is beyond the scope of this article but it would be fair to say that there has been a substantial reduction in the enthusiasm about this compound in the last few years. In 2013, GSK announced that it was closing its Sirtis research facility in Cambridge Massachusetts (the home of Harvard University) and absorbing the company into the parent company and moving some of the Sirtis research team to its site in Philadelphia. The medical media interpreted this as a sign of the company’s waning enthusiasm and confidence in the immediate financial potential of resveratrol and other Sirt1 activating compounds. The concentration of resveratrol in most red wines is usually well below 2mg per litre and even the positive effects seen in experimental studies with resveratrol require doses that could not reasonably be obtained from drinking red wine. It seems increasingly improbable that any putative health benefits of moderate red wine consumption could be due to its resveratrol content.

How important was Das to resveratrol?

In November 2014, Scopus listed just over 5000 publications with “resveratrol” in the title and Das was the single name most commonly associated with these papers even though his career effectively ended around four years earlier. Papers from Das were restricted to the cardiovascular effects of resveratrol and were not generally very highly cited. Despite his numerical prominence, some others working in the resveratrol field sought to play down the importance of his work to the field after his fraudulent activity was exposed. According to Tom Bartlett writing in the Chronicle of Higher Education they implied that the discrediting of his work would cause limit impact on the field of resveratrol research. Professor Sinclair initially said, when interviewed just after the news of the scandal broke, that he had to look up who Dipak Das was, although it later turned out that he had cited Das in his own papers and had served on a committee with him in the past. He also questioned the impact of his work because it was not published in leading molecular biology journals. Dr Linda Partridge of University College London, an expert on ageing research who had recently published a paper about resveratrol in Nature, also said that she had not heard of Das and doubted that his disgrace would have much impact except maybe to put some people off studying resveratrol. Richard Miller of the University of Michigan at Ann Arbor also said that although he was familiar with the field he had not heard of Das before the allegations became public. His take on the whole field of resveratrol research was generally sceptical and he said that he thought that;

“Dr Das’s troubles will not have much impact on the juggernaut of resveratrol research”

Joseph Baur, an assistant professor at the University of Pennsylvania also did not think that the discrediting of Das’s work would have much effect on the field. He said that Das published mainly on the cardiovascular effects of resveratrol and even then “the cardiovascular benefits of red wine were not built upon Dipak Das’s work”. Baur was a past graduate student of David Sinclair’s and had recently published a negative report on the ability of resveratrol to extend lifespan in normal lean mice.

The accusations against Das

I have derived most of the material in this section from a hard copy of the official report of the investigation into the Das affair by the University of Connecticut. This was supplied to me after a request citing the State of Connecticut’s Freedom of Information legislation.

An allegation of research misconduct was made to the US Office of Research Integrity (ORI) relating to a, now retracted, 2008 paper about resveratrol published in the journal Free Radical Biology and Medicine. Notification of this allegation was sent to the University of Connecticut who set up a special review board to investigate not only the specific allegations relating to this so-called index paper but also 101 other publications by Das published in the six years before the allegation. They also looked at two PhD theses awarded by the University of Debrecen in Hungary but which were partly conducted under Das’s supervision in Connecticut i.e. those of Dr Samarjit Das and Dr Norbert Nagy. The special review board also considered the integrity of a number of grant applications made by Das.

The initial allegations suggested two of the images of what are called western blots in the index paper had been improperly manipulated; image fraud has become a major reason for complaints made to the ORI in the USA. Western blotting is a technique used to separate proteins and these proteins, when appropriately stained, show up as a series of dark bands which can be attributed to specific proteins. The initial allegations of manipulation of these bands in the index paper were confirmed by the review board which contained senior academics with expertise in western blotting. The committee decided to focus on 26 of the more than 100 papers designated for scrutiny and to look specifically at the western blot images in these papers. In total the review board were unanimously agreed that at least 145 western blot images have been manipulated in a manner that constituted research misconduct and these images were spread over 25 publications and 3 grant applications. The review board believed it was probable that other images had been manipulated as well as those where they were confident that this had occurred. They concluded that several different types of manipulation of real western blot images had been executed using Adobe Photoshop software. These manipulations included:

• Splicing together of different western blot images and then presenting them as if they had been produced from the same experiment
• Pasting bands into an otherwise normal blot and then presenting them as if they had been generated during the experiment
• Completely or partly erasing or otherwise modifying specific bands in a blot.

They concluded that Das was the major culprit in generating these images and they list several reasons for this conclusion including those below.

• He was the only common author on all affected papers and in all but one case he was the senior author.
• Images at various stages of manipulation were found on a computer to which it was said that Das had sole access and he appeared to be the final person to access the manipulated images.
• E-mail correspondence on his computer seemed to be asking more junior staff to alter western blot images in specific and improper ways.
• Many of those performing experiments and who were first authors on some papers were not involved in the final biochemical analyses and generation of the western blot images.
• Some of the papers with the worst examples of image manipulation were submitted some considerable time after the first authors had left the university.
• Some members of the then current staff did not know who had made the images for papers on which they were first authors and they claim not to have seen drafts of these papers until after they were published.

A preliminary review of the two PhD theses partly conducted in Connecticut but with awards from the University of Debrecen contained images that showed evidence of similar manipulation to those found in the papers assessed in detail; these concerns were passed on but they restricted themselves to considering the actions of Dipak Das. The committee also considered that other members of the staff working with Das might have committed acts of research misconduct but their names have understandably been redacted from my copy of the report.

Das was dismissed in early 2012 and the Board of Trustees of the University of Connecticut unanimously affirmed that decision in August of that year. Das denied any wrongdoing and filed a $35 million claim for compensation for defamation of his character. This legal case was unresolved at the time of his death. His response to the draft report of the University’s special board was made public. In two letters in the summer of 2010 he denies all of the accusations against him. He complains that he has been asked to respond to thousands of pages of material at a time when his health has been poor and adversely affected by the stress of the allegations against him. He claims that the initial complaint to the ORI which triggered the investigation was made by a person with a grudge against him and who might have had access to his computer. In a rambling 7 page letter in June 2010 he alleges that there was prejudice against Indian scientists by some of the senior staff at the University and that the findings against him were motivated by this specific racism against Indians but not members of staff from other ethnic minorities; he suggests that there had been a long standing conspiracy against him and other Indian members of his team.

Bill Sardi wrote a long defence of Das, shortly after the accusations against him were made public and this was reprinted in an article by Larry Husten in CardioBrief . Das and Sardi were attending the same conference on resveratrol in Kolkata, India when the news story broke. He claims that his rebuttal of the allegations was based upon detailed discussions with Das and two of his ex-students and co-authors who were also attending the conference. The long defence of Das makes the following claims.

• The allegedly faulty tests did not materially affect the main findings of Das and his research group in relation to resveratrol.
• The main findings of Das and his group had been confirmed in other studies.
• That the initial whistle-blower who contacted the ORI was someone who worked in Das’s lab and may have had a grudge against him.
• Das’s computer was actually accessible to others and not just Das as claimed by the University of Connecticut review board; these others were said to include the alleged whistle-blower.
• According to Dr Das it was normal practice to alter western blot images for publication.

This last suggestion is hard to accept given the nature of the manipulations that are said to have been made. Whilst it may be acceptable to enhance an image to make it clearer in a printed paper (e.g. by altering the contrast), making changes that materially alter the image and change its interpretation (e.g. removing or adding bands or splicing together different images) would be unacceptable. It would have to be explicitly stated in the paper exactly what changes had been made and why they were justified.

• That a conspiracy by medical and pharmaceutical interests was seeking to suppress evidence that the resveratrol products like that produced by his company could effectively replace some expensive drugs and treatments.

He quotes several anecdotal examples of people who have been cured by use of his product and some examples of where these vested interests have warned off or suppressed researchers trying to test the efficacy of the product. In one part of this letter he makes the following statement:

Resveratrol is an antidepressant, an anti-inflammatory, an anti-bacterial, antifungal, anti-viral, anti-cancer, cholesterol-lowering, liver cleansing, brain enhancing molecule. If Americans embraced resveratrol pills en masse, many prescription drugs would not be needed. Modern pharmacology and its model of developing a single synthetically-made molecule to treat every disease, would become antiquated.”

I would not recommend panic selling of your shares in pharmaceutical companies as a result of this piece but I might be tempted to take the occasional precautionary glass of good red wine! In his CardioBrief article Husten quotes from a 2011 scientific review article which lists Dipak Das as one of the co-authors:

“The overall conclusion is that published evidence is not sufficiently strong to justify a recommendation for the administration of resveratrol to humans, beyond the dose that can be obtained from dietary sources.”  Ahmad and colleagues, 2011.

At the end of his statement Sardi argues that long term placebo-controlled trials would unreasonably deprive many people of this panacea during the course of these studies which are unnecessary because the product is natural and safe. He argues that it would cost much time and money to get evidence that this natural product, sold as a dietary supplement, was an effective drug in the treatment of a single condition. He also doubts whether he could rely upon doctors to honestly conduct studies on a product that might effectively put them out of business. He seems to be suggesting that his company’s resveratrol preparation must be safe as it is a natural product and that we should assume that it is effective to avoid delaying its use! After his death, Sardi also wrote a very pro-Das obituary which suggests that he was a major contributor to medical knowledge and that he had been vindicated over allegations of scientific fraud.

My assessment

Having read the main body of the report of the University of Connecticut Health Center Special Review Board, I am satisfied beyond reasonable doubt that multiple acts of research misconduct were committed in the production of papers and grant applications with which Dipak Das was involved. The only realistic alternative is that several members of this committee wilfully conspired to discredit Das on the basis of false or exaggerated evidence. The report also convinces me that Das was the main perpetrator of these fraudulent activities although the issue of whether others within the Center may also have acted improperly is not resolved and the review board made clear that they had left resolution of this issue to others. In terms of sheer numbers of papers, Das certainly was a significant contributor to the field of resveratrol research in the specific area of the cardiovascular benefits of resveratrol. The conclusions from the review of Ahmad and colleagues that there is little justification for taking supplementary doses of resveratrol was made before the retraction of the generally favourable reports by Das.

A bizarre footnote to this affair

Das died on 19th September 2013 and the web-site RETRACTIONWATCH highlighted an odd footnote to this tale. A paper was published in January 2014 that listed Das both as the senior author and the corresponding author. The paper was apparently revised on 18th October 2013 (i.e. a month after his death) but he is still listed as corresponding author and his e-mail address given for correspondence. It would not be unusual for co-authors in these circumstances to send back the revised manuscript but it would be normal to change the contact address to that of one of the living authors and to note the death of the senior author. It is disturbing that four of the references cited in this paper are on the list of retracted papers by Das and they were all retracted before the revised manuscript was sent back and three of them were retracted before the original version was submitted.

The RETRACTIONWATCH web-site also noticed another oddity about this affair. In the same October 2012 issue of the Journal of Cellular and Molecular Biology there were two retraction notices for papers by Das as well as a new paper with him as the senior author. This new paper was accepted a year earlier i.e. before the results of the University of Connecticut investigation were made public. Nevertheless it seems rather bizarre that no-one with editorial oversight saw any problem with printing two retractions for fraudulent activity in the same issue as another paper from the same disgraced author. This paper also cites three of his now retracted papers

Bibliography

University of Connecticut Health Center. Special Review Board Report. Investigation of allegation of research misconduct. Office of Research Integrity Case #DIO 3995.

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