Gene Expression Profile of Vascular Endothelial Growth Factors (VEGFs) and Platelet-derived Growth Factors (PDGFs) in the Normal Cornea

Background/Aim: Angiogenic growth factors expression is not known in the normal cornea. The aim was to study corneal gene expression profile of VEGF and PDGF pathways influencing the avascular state of cornea. Materials and Methods: cDNA synthesis was performed from mRNA extracted from five fresh pig corneas followed by cDNA synthesis and analysis of VEGF and PDGF pathways by TaqMan Array gene expression profile. Results: Normal pig cornea lacks VEGFR2 and VEGFR3 gene expression. MK2 and AKT1 genes were significantly overexpressed (p=0.000684, p=0.050995, respectively). Six PDGF pathway genes were overexpressed: TIAM1 (p=0.047), PIK3CA (p=0.00005), IKBKG (p=0.000006), PAK4 (p=0.034), RAC1 (p=0.000006 and PTGS2, p=0.00375). PDGF A was up regulated, but not with a statistical significance (p=0.79911), while PDGFR alpha was down-regulated and PDGFR beta was not expressed. Conclusion: Normal cornea avascularity is given by growth factor receptors down-regulation. Rapid corneal neovascularisation is induced by activation of the main angiogenic growth factors that induce angiogenic cascade and vessel recruitment.

Automated summary

The study on gene expression profile of normal pig cornea revealed the lack of VEGFR2 and VEGFR3 gene expression, while MK2 and AKT1 genes were significantly overexpressed. Multiple genes in the PDGF pathway were also found to be overexpressed, indicating the avascular state of the cornea is related to the down-regulation of growth factor receptors.