In vitro/vivo drug release and anti-diabetic cardiomyopathy properties of curcumin/PBLG-PEG-PBLG nanoparticles
Authors: Haiying Jiang
Bo Dong
Fei Tong
Rongkui Chai
Journal: International Journal of Nanomedicine (2018)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: CSE; CaSR; PBLG-PEG-PBLG; curcumin; diabetic cardiomyopathy.
Affiliations: Department of Pathology and Pathophysiology, Provincial Key Discipline of Pharmacology, Jiaxing University Medical College, Jiaxing, Zhejiang, People's Republic of China.

Abstract:  Background: The objective of this study was to survey the therapeutic function of curcumin-encapsulated poly(gamma-benzyl l-glutamate)-poly(ethylene glycol)-poly(gammabenzyl l-glutamate) (PBLG-PEG-PBLG) (P) on diabetic cardiomyopathy (DCM) via cross regulation effect of calcium-sensing receptor (CaSR) and endogenous cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S). Methods: Diabetic rats were preconditioned with 20 mg/kg curcumin or curcumin/P complex continuously for 8 weeks. The blood and myocardiums were collected, the level of serum H2S was observed, and the [Ca2+]i content was measured in myocardial cells, and hematoxylin-eosin, CaSR, CSE, and calmodulin (CaM) expression were detected. Results: Both curcumin and curcumin/P pretreatment alleviated pathological morphological damage of myocardium, increased H2S and [Ca2+]i levels, and upregulated the expression of CaSR, CSE, and CaM as compared to DCM group, while curcumin/P remarkably augmented this effect. Conclusion: PBLG-PEG-PBLG could improve water-solubility and bioactivity of curcumin and curcumin/PBLG-PEG-PBLG significantly alleviated diabetic cardiomyopathy. 

Retracted: Yes

PubPeer comments:
 Microscope Images in Figure 5 appear to overlap (5A(a) and 5A(b)) apparently with different magnification, but described as a different group. Overlap roughly illustrated with red boxes. u201dFigure 5 (A) histopathologic assessment of myocardial damage... Notes: (A) light microscope images (u00d7100) in *sham group (a)*, *DM-4w group (b)*, and DM-8w group (c).u201d *** ![file] , 
 Figure 7F. * Panels a (sham) and e (curcumin+CaRS group) appear to show an area of overlap (shown in purple). * Panels d (curcumin P group) and f (curcumin P+CaRS group) appear to show an area of overlap (shown in blue). For both pairs, aspect ratio and color are different,, suggesting these are more than just simple duplications. ![file] , 
 Figure 8A. * In panel a (Sham), the same group of three cells appears to be visible twice (shown in lime green). * Panels g (curcumin+CaRS+PAG group) and h (curcumin P+CaRS+PAG group) appear to be identical, although color and certain areas in the middle right of the photo might be slightly different. Shown with orange boxes. ![file] , 
 Figure 9A. In panels b and e some cells appear to be visible multiple times within the same photo. Here is a Forensically analysis: ![file] , 
 Figure 9B. Note that panels a through d show the same experiments as shown in Figure 9A, which is confusing, but not of concern here. What is of concern is that all the cells in e and all the cells in f appear to look similar to each other. Shown here in aqua and yellow. ![file] , 
 We thanks the Elisabeth M Bik s comments firstly. We answer the question as following: 1.We thnaks these comments. Thank you very much for careful reading and found out the mistake in the Figures. We carfully checked our original pictures. I remain confident about the validity of the scientific conclusions made in this publication and our worku2019s reproducibility. These tissues in different groups are placed on the same slide glass and are observed in Figure 5A, Figure 7F and Figure 8A. The image in the pictures are a little repeated regions. But these do not affect our results. This phenomenon is found in many literatures . 2.We thnaks these comments. Thank you very much for careful reading and found out the mistake in the Figures. We carfully checked our original pictures. I remain confident about the validity of the scientific conclusions made in this publication and our worku2019s reproducibility. Cell staining is poor and is not clear, so it is deemed to confuse. The result is no problem. , 
 Dear Dr. Dong, I am afraid your confidence in your results does not match my visual observations that several image panels or features within photos appear to look identical.  This phenomenon is found in many literatures also does not match my screening of 80,000 biomedical papers for image duplications (my screening of the first 20,000 was published here: https: mbio.asm.org content 7 3 e00809-16). Rather, these duplications are of severe concern, in my professional opinion. It would help if you could post some higher resolution images straight from the microscope camera. , 
 #6  The image in the pictures are a little repeated regions. But these do not affect our results. This phenomenon is found in many literatures The prevalence of faked results is no excuse. , 
 ![file] Panels c, d, g, h might benefit from a false-colour LUT. , 
 ![file] ![file] , 
 Retracted [25 May 2021] . ------------------------------------ At the request of the authors, the Editor and Publisher of International Journal of Nanomedicine wish to retract the published article. We were notified by the authors of potential issues relating to the reliability of the data in the published article. Specifically: - Figure 5A panel a (Sham group) appears to be duplicated with Figure 5A panel b (DM-4w group). - Figure 7A panel g (Curcumin+CaRI group) appears to be duplicated with Figure 7A panel h (Curcumin P+CaRI group). - Figure 7F panel a (Sham group) appears to be duplicated with Figure 7F panel e (Curcumin+CaRS group). - Figure 7F panel d (Curcumin P group) appears to be duplicated with Figure 7F panel f (Curcumin P+CaRS group). - Figure 8A panel g (Curcumin+CaRS+PAG group) appears to be duplicated with Figure 8A panel h (Curcumin P+CaRS+PAG group). - Figure 9A panels b and e appear to show repeated elements. - Figure 9B panels b, e and f appear to show repeated elements. The authors explained mistakes were made due to carelessness during the preparation of the figures which led to the duplicated images. The authors requested for the article to be retracted and wish to apologise for this error. Our decision-making was informed by our policy on publishing ethics and integrity and the COPE guidelines on retraction. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as u201cRetractedu201d. ,