Researchers have corrected three studies published in the journal Diabetes after users flagged issues with the images on PubPeer.
All three papers share a number of authors, including the same last and corresponding author, Aimin Xu, from The University of Hong Kong.
Since the corrections appear relatively extensive, we asked the journal if retractions were ever on the table. According to Chris Kohler, associate publisher, scholarly journals at American Diabetes Association, which publishes Diabetes, an ethical panel reviewed the papers before allowing the authors to issue the errata, all of which were published online this month:
The corresponding author’s request to amend the three articles was reviewed by the American Diabetes Association’s Panel on Ethical Scientific Programs (ESP). After reviewing the corresponding author’s source materials, lab notes, responses to questions raised by the ESP, etc., the Panel approved the author’s request to publish errata to address the issues cited on PubPeer.com for these three papers.
Xu told Retraction Watch in an email:
As explained in the statements of errata, the mistakes were made during the image assembly. For the 2011 Diabetes paper, an extra blank lane was included, which does not affect conclusion at all. For 2007 and 2011 Diabetes paper, we have kept all the original records including autographs and original images, and submitted all the original records to the journal for inspections.
He noted:
The corrected images are based on our original records, and all these corrections do not alter the conclusions at all.
Here’s the first erratum for “Adiponectin-Induced Endothelial Nitric Oxide Synthase Activation and Nitric Oxide Production Are Mediated by APPL1 in Endothelial Cells:”
In the article listed above, several erroneous duplications were made during the process of image assembly. The duplications occurred in lanes 4 and 5 of the total AMPK strip in Fig. 4B; lanes 4 and 5 of the total eNOS strip in Fig. 4B; lanes 5 and 6 in the eNOS strip in Fig. 5; lanes 3–5 and 6–8 in the eNOS strip in Fig. 6A; lanes 1, 3, 5, and 7 of the immunoprecipitated eNOS strip in Fig. 6A; and lanes 1 and 3 in HSP90 strips in Fig. 6A. In these strips, splicing between some of the bands was performed within the same gel to remove extra lanes or to rearrange the order of the samples. The authors have now provided the correctly assembled images with a clear indication of spliced bands using a dividing line in Figs. 4B, 5, and 6A. The figure legends remain unchanged. The authors apologize to the readers for any confusion.
This 2007 paper has been cited 160 times, according to Clarivate Analytics’ Web of Science, formerly part of Thomson Reuters. Here is its associated PubPeer thread.
Here’s the next erratum:
In the article listed above, the quantitative bar graph in Fig. 5C was from real-time PCR analysis using SYBR Green dye, whereas the gel images inserted in this panel were from a separate set of reverse transcription (RT)-PCR analyses to confirm the specificity of the primers used, but not for real-time PCR. An additional lane at the right end of the gels (lane 7) was erroneously included. The revised version of Fig. 5C includes corrected gel images. The dividing line between lanes 5 and 6 of p16 PCR products shows splicing within the same gel. In the legend of Fig. 5C, the statement “The representative gel is shown on the top of the bar chart” is now changed to “The gel images on the top of the bar chart are RT-PCR products for p16 and actin.” The authors apologize to the readers for any confusion.
This 2010 paper, “Adiponectin Prevents Diabetic Premature Senescence of Endothelial Progenitor Cells and Promotes Endothelial Repair by Suppressing the p38 MAP Kinase/p16INK4A Signaling Pathway,” has accumulated 60 citations. Here is the relevant PubPeer thread.
And here’s the final erratum:
In the article listed above, an erroneous duplication was made during the process of image assembly for total ERK1/2 in Fig. 4A. Lanes 4 and 5 in the original experiment were duplicated by mistake when loading the samples during SDS-PAGE. In order to remove lane 5 for a unified presentation in Fig. 4A, the authors created a new file to assemble the image by copying and pasting the first four lanes in the STD group and the last four lanes in the HFD group. However, the last four lanes were copied twice by mistake. The right panel in this revised version shows the correctly assembled image for total ERK1/2 from the original data, which is shown in the left panel. This error was unintentional. In addition to total ERK1/2, total Akt and α-actin are appropriate as loading controls for this experiment. The authors apologize to the readers for any confusion.
The 2011 paper, “APPL1 Counteracts Obesity-Induced Vascular Insulin Resistance and Endothelial Dysfunction by Modulating the Endothelial Production of Nitric Oxide and Endothelin-1 in Mice,” has garnered 28 citations. Here is its PubPeer thread.
Paul Vanhoutte, Yu Wang, Wing-Tak Wong and Donghai Wu are each listed as authors on two of the now-corrected papers.
Several other papers by corresponding author Xu are being questioned on PubPeer, all for image-related issues.
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