Anthocyanin-rich purple corn extract inhibit diabetes-associated glomerular angiogenesis

PLoS One. 2013 Nov 20;8(11):e79823. doi: 10.1371/journal.pone.0079823. eCollection 2013.

Abstract

Diabetic nephropathy (DN) is one of the major diabetic complications and the leading cause of end-stage renal disease. Abnormal angiogenesis results in new vessels that are often immature and play a pathological role in DN, contributing to renal fibrosis and disrupting glomerular failure. Purple corn has been utilized as a daily food and exerts disease-preventive activities. This study was designed to investigate whether anthocyanin-rich purple corn extract (PCE) prevented glomerular angiogenesis under hyperglycemic conditions. Human endothelial cells were cultured in conditioned media of mesangial cells exposed to 33 mM high glucose (HG-HRMC-CM). PCE decreased endothelial expression of vascular endothelial growth factor (VEGF) and hypoxia inducible factor (HIF)-1α induced by HG-HRMC-CM. Additionally, PCE attenuated the induction of the endothelial marker of platelet endothelial cell adhesion molecule (PECAM)-1 and integrin β3 enhanced in HG-HRMC-CM. Endothelial tube formation promoted by HG-HRMC-CM was disrupted in the presence of PCE. In the in vivo study employing db/db mice treated with 10 mg/kg PCE for 8 weeks, PCE alleviated glomerular angiogenesis of diabetic kidneys by attenuating the induction of VEGF and HIF-1α. Oral administration of PCE retarded the endothelial proliferation in db/db mouse kidneys, evidenced by its inhibition of the induction of vascular endothelium-cadherin, PECAM-1 and Ki-67. PCE diminished the mesangial and endothelial induction of angiopoietin (Angpt) proteins under hypeglycemic conditions. The induction and activation of VEGF receptor 2 (VEGFR2) were dampened by treating PCE to db/db mice. These results demonstrate that PCE antagonized glomerular angiogenesis due to chronic hyperglycemia and diabetes through disturbing the Angpt-Tie-2 ligand-receptor system linked to renal VEGFR2 signaling pathway. Therefore, PCE may be a potent therapeutic agent targeting abnormal angiogenesis in DN leading to kidney failure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthocyanins / metabolism
  • Antigens, CD / metabolism
  • Blotting, Western
  • Cadherins / metabolism
  • Cell Line
  • Cell Proliferation / drug effects
  • Diabetes Mellitus / drug therapy*
  • Enzyme-Linked Immunosorbent Assay
  • Human Umbilical Vein Endothelial Cells / drug effects
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • In Vitro Techniques
  • Integrin beta3 / metabolism
  • Kidney Glomerulus / blood supply*
  • Kidney Glomerulus / cytology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neovascularization, Pathologic / drug therapy
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use*
  • Platelet Endothelial Cell Adhesion Molecule-1 / metabolism
  • Thrombospondin 1 / metabolism
  • Vascular Endothelial Growth Factor A / metabolism
  • Zea mays / chemistry*

Substances

  • Anthocyanins
  • Antigens, CD
  • Cadherins
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Integrin beta3
  • Plant Extracts
  • Platelet Endothelial Cell Adhesion Molecule-1
  • Thrombospondin 1
  • Vascular Endothelial Growth Factor A
  • cadherin 5

Grants and funding

This study was supported by the National Research Foundation of Korea through the Human Resource Training Project for Regional Innovation (2012-01-A-05-003-12-010100) and by a grant from the Ministry for Food, Agriculture, Forestry and Fisheries through the Korea Institute of Planning and Evaluation for Technology of Food, Agriculture, Forestry and Fisheries (109163-03-1-SB030). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.