Vitamin D improves vascular function and decreases monoamine oxidase A expression in experimental diabetes

Mol Cell Biochem. 2019 Mar;453(1-2):33-40. doi: 10.1007/s11010-018-3429-2. Epub 2018 Aug 30.


The active form of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)2D3), was reported to improve vascular function in patients with diabetes, yet the underlying mechanisms remain to be fully elucidated. Monoamine oxidase (MAO), a mitochondrial enzyme, with two isoforms (A and B) that generates hydrogen peroxide (H2O2) as by-product, has been recently reported to contribute to the pathogenesis of endothelial dysfunction in diabetes. The present study assessed the interaction between vitamin D and MAO in the vascular wall in the setting of type 1 experimental diabetes. To this aim, diabetes was induced in male Wistar rats via a single injection of streptozotocin (STZ, 50 mg/kg, IP) and 1 month later thoracic aortas were harvested and used for organ bath studies and H2O2 measurements. MAO expression was assessed by immunohistochemistry and RT-PCR. Endothelial function was evaluated in isolated aortic rings in the absence vs. presence of 1,25(OH)2D3 (100 nM, 24 h incubation). In diabetic animals, we found a significant reduction in the endothelial-dependent relaxation to acetylcholine and an increased expression of the MAO-A isoform, respectively. Vitamin D significantly improved vascular function, mitigated oxidative stress and decreased MAO-A expression in diabetic vascular preparations. In conclusion, MAO-A is induced in diabetic aortas and vitamin D can improve diabetes-induced endothelial dysfunction by modulating the MAO-A expression.

Keywords: Endothelial dysfunction; Experimental diabetes mellitus; Monoamine oxidase; Vitamin D.

MeSH terms

  • Animals
  • Aorta / enzymology*
  • Aorta / pathology
  • Calcitriol / pharmacology*
  • Diabetes Mellitus, Experimental / enzymology*
  • Diabetes Mellitus, Experimental / pathology
  • Endothelial Cells / enzymology*
  • Endothelial Cells / pathology
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Male
  • Monoamine Oxidase / biosynthesis*
  • Rats
  • Rats, Wistar


  • Monoamine Oxidase
  • Calcitriol