Differential expression of vascular endothelial growth factor isoforms and receptor subtypes in the infarcted heart

Aims

The vascular endothelial growth factor (VEGF) family contains four major isoforms and three receptor subtypes. The expressions of each VEGF isoform and receptor subtype in cardiac repair/remodeling after myocardial infarction (MI) remain uncertain and are investigated in the current study.

Methods and results

Temporal and spatial expressions of VEGF isoforms and VEGFR subtypes were examined in the infarcted rat heart. Sham-operated rats served as controls. We found that the normal myocardium expressed all VEGF isoforms. Following MI, VEGF-A was only increased in the border zone at day 1 and was significantly decreased in the infarcted heart during the 42 day observation period afterwards. VEGF-B was significantly suppressed in the infarcted heart. VEGF-C and VEGF-D were markedly increased in the infarcted heart in both early and late stages of MI. VEGFR-1 and 2 were significantly decreased in the infarcted heart, while VEGFR-3 was significantly increased, which was primarily expressed in blood vessels and myofibroblasts (myoFb).

Conclusions

VEGF isoforms and VEGFR subtypes are differentially expressed in the infarcted heart. Increased VEGF-A in the very early stage of MI suggests the potential role in initiating the cardiac angiogenic response. Suppressed cardiac VEGF-B postMI suggests that it may not be critical to cardiac repair. The presence of enhanced VEGF‐C and VEGF-D along with its receptor, VEGFR-3, in various cell types of the infarcted heart suggest that these isoforms may regulate multiple responses during cardiac repair/remodeling.