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Vascular endothelial growth factor is increased in devascularized rat islets of Langerhans in vitro.
Journal article

Vascular endothelial growth factor is increased in devascularized rat islets of Langerhans in vitro.

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  • 1997-02-15
Published in:
  • Transplantation. - 1997
Animals
Cell Separation
Endothelial Growth Factors
Hypoxia
Insulinoma
Islets of Langerhans
Lymphokines
Neovascularization, Physiologic
Pancreatic Neoplasms
Rats
Rats, Inbred Strains
Tumor Cells, Cultured
Vascular Endothelial Growth Factor A
Vascular Endothelial Growth Factors
English Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen with potent angiogenic and vascular permeability-inducing properties, both of which may be important for the function of islets of Langerhans. In this study, we have examined the expression of VEGF and its tyrosine kinase receptors (flt and flk-1) in isolated rat islets of Langerhans in vitro. When analyzed by in situ hybridization, islet tissue showed a significant 4.6-fold increase in VEGF mRNA expression over time in culture from 0 to 7 days. Islet tissue exposed to hypoxic/anoxic conditions for a period of 8 hr showed a 3.7-fold increase in VEGF mRNA when analyzed by Northern blot hybridization. Reverse transcriptase-polymerase chain reaction revealed the presence of both flt and flk-1 in freshly isolated islets, and two VEGF isoforms, namely VEGF120 and VEGF164. Three rodent beta-cell lines derived from insulinomas (RINm5F-2A, INS-1, and MIN6) were also found to express VEGF by Northern blot hybridization. However, neither hypoxia/anoxia nor low (0.3 g/L)- or high (3.0 g/L)-glucose culture conditions modulated their expression of VEGF. VEGF derived from RINm5F-2A cells was bioactive in a three-dimensional in vitro model of angiogenesis, which assays for endothelial cell invasion and capillary morphogenesis. These findings demonstrate, first, that devascularization increases VEGF expression in isolated islet tissue, and they point to VEGF as a potentially important endogenous angiogenic stimulus for subsequent revascularization in vivo. Second, our observations raise the possibility that survival of transplanted islets may be improved by increasing VEGF expression before transplantation.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.ch/global/documents/195449
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