Conditional hypovascularization and hypoxia in islets do not overtly influence adult β-cell mass or function

Diabetes. 2013 Dec;62(12):4165-73. doi: 10.2337/db12-1827. Epub 2013 Aug 23.

Abstract

It is generally accepted that vascularization and oxygenation of pancreatic islets are essential for the maintenance of an optimal β-cell mass and function and that signaling by vascular endothelial growth factor (VEGF) is crucial for pancreas development, insulin gene expression/secretion, and (compensatory) β-cell proliferation. A novel mouse model was designed to allow conditional production of human sFlt1 by β-cells in order to trap VEGF and study the effect of time-dependent inhibition of VEGF signaling on adult β-cell fate and metabolism. Secretion of sFlt1 by adult β-cells resulted in a rapid regression of blood vessels and hypoxia within the islets. Besides blunted insulin release, β-cells displayed a remarkable capacity for coping with these presumed unfavorable conditions: even after prolonged periods of blood vessel ablation, basal and stimulated blood glucose levels were only slightly increased, while β-cell proliferation and mass remained unaffected. Moreover, ablation of blood vessels did not prevent β-cell generation after severe pancreas injury by partial pancreatic duct ligation or partial pancreatectomy. Our data thus argue against a major role of blood vessels to preserve adult β-cell generation and function, restricting their importance to facilitating rapid and adequate insulin delivery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Hypoxia / metabolism
  • Hypoxia / physiopathology*
  • Insulin / metabolism
  • Insulin-Secreting Cells / physiology*
  • Ischemia / metabolism
  • Ischemia / physiopathology*
  • Islets of Langerhans / blood supply*
  • Islets of Langerhans / metabolism
  • Islets of Langerhans / physiopathology
  • Mice
  • Neovascularization, Pathologic / metabolism
  • Neovascularization, Pathologic / physiopathology*
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor Receptor-1 / metabolism

Substances

  • Insulin
  • Vascular Endothelial Growth Factor A
  • Flt1 protein, mouse
  • Vascular Endothelial Growth Factor Receptor-1