Fig. 1

Diabetes is associated with cardiac fibrosis and EndMT in the heart. A Trichrome staining shows increased fibrosis around large vessels and in the cardiac interstitium of diabetic patients (scoring 3, in contrast to mostly 1 in non-diabetic individuals). mRNA expressions of endothelial markers B PECAM1 and C CDH5 were significantly decreased, while mRNA expressions of mesenchymal markers D) COL1A1 and E TAGLN were significantly higher in diabetic compared to non-diabetic patients. Expressions of pro-EndMT regulators, F the profibrotic mediator TGFB1 and G the proinflammatory cytokine IL6 were also higher in diabetic patients. H Immunofluorescence showed that the endothelial marker CD31 (green) was highly expressed in the small vessels in the hearts of non-diabetic patients while SM22 (red) showed minimal immunofluorescence in these vessels, indicating minimal expression. Diabetic patients showed weaker CD31 staining and stronger SM22 staining in the small vessels of the heart, they also showed overlapping red-green fluorescence, reflecting co-localization of the two markers, indicating EndMT. [white bar = 200 μm in trichrome; representative images were chosen; mRNA expressions normalized to ACTB mRNA; n = 10 for non-diabetic and n = 28 for diabetic in trichrome and mRNA analyses; data presented as scatter plots with mean ± standard deviation; * = p < 0.05, ** = p < 0.01, *** = p < 0.001, ****p < 0.0001 as determined by Student’s T-test; white bar = 50 μm in fluorescence images; images were uniformly adjusted to reduce background noise; representative images were chosen; n = 7 for non-diabetic and n = 10 for diabetic for fluorescence imaging]