Oral chromium picolinate impedes hyperglycemia-induced atherosclerosis and inhibits proatherogenic protein TSP-1 expression in STZ-induced type 1 diabetic ApoE−/− mice
Authors: Priya Raman
Rituparna Ganguly
Rebecca Haney
Siri Yalamanchili
Vahagn Ohanyan
Soumyadip Sahu
Ronaldo J Chavez
Shivani Shah
Journal: Scientific Reports (2017)
Discipline: Multidisciplinary
Keywords: thrombospondin-1; TSP-1; chromium picolinate; atherosclerosis; diabetes
Affiliations: Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272, USA.

Abstract:  Increasing evidence suggests thrombospondin-1 (TSP-1), a potent proatherogenic matricellular protein, as a putative link between hyperglycemia and atherosclerotic complications in diabetes. We previously reported that the micronutrient chromium picolinate (CrP), with long-standing cardiovascular benefits, inhibits TSP-1 expression in glucose-stimulated human aortic smooth muscle cells in vitro. Here, we investigated the atheroprotective action of orally administered CrP in type 1 diabetic apolipoprotein E-deficient (ApoE-/-) mice and elucidated the role of TSP-1 in this process. CrP decreased lipid burden and neointimal thickness in aortic root lesions of hyperglycemic ApoE-/- mice; also, smooth muscle cell (SMC), macrophage and leukocyte abundance was prevented coupled with reduced cell proliferation. Attenuated lesion progression was accompanied with inhibition of hyperglycemia-induced TSP-1 expression and reduced protein O-glycosylation following CrP treatment; also, PCNA and vimentin (SMC synthetic marker) expression were reduced while SM-MHC (SMC contractile marker) levels were increased. To confirm a direct role of TSP-1 in diabetic atherosclerosis, hyperglycemic TSP-1-/-/ApoE-/- double knockout mice were compared with age-matched hyperglycemic ApoE-/- littermates. Lack of TSP-1 prevented lesion formation in hyperglycemic ApoE-/- mice, mimicking the atheroprotective phenotype of CrP-treated mice. These results suggest that therapeutic TSP-1 inhibition may have important atheroprotective potential in diabetic vascular disease. 

Retracted: No

PubPeer comments:
 Images in Figure 5 appear unexpectedly similar when flipped vertically (green boxes). *** ![file] *** Caption ![file] , 
 #1 Thank you for reaching out. The marked images (green boxes) indeed represent the same H E image corresponding to sections taken from the same animal and stained for CD68 and CD45 (shown in Fig 5a and 5c). The H E image shown for STZ+CrP group in Fig 5c was flipped to match with the orientation of the corresponding CD45-stained image for clarity of presentation. Sincerely, P. Raman , 
 #2 Thank you for clarifying. , 
 #2 Many thanks Dr Raman, From your own Methods section:  Briefly, tissue sections were incubated in ice-cold acetone (5u201310u2009mins) and blocked with 5% donkey or goat serum (90u2009mins) at room temperature. Following an overnight incubation with primary antibodies (anti-PCNA-1:200; anti-u03b1-SMA-1:200; anti-CD68u20131:50; anti-CD45u20131:150; anti-Ki67-1:100) at 4u2009u00b0C, sections were incubated with Alexa Fluor 488 goat anti-mouse (for u03b1-SMA) or Alexa Flour 594 donkey anti-rabbit IgG secondary antibodies (1:1000 or 1:500) and mounted on DAPI-containing mounting media (Vectashield, Vector Laboratories). For co-staining experiments, consecutive slides from serial sections were sequentially stained first with PCNA antibody followed by u03b1-SMA antibody.  In brief, CD68 and CD45 are not co-stainings, but two separate stainings on separate sections. Which in theory cannot look so identical. ,