Identification of a specific pattern of downregulation in expression of isoforms of vascular endothelial growth factor in dilated cardiomyopathy.

Recent work suggests that myocardial hypoxia or ischaemia are also pathophysiologic factors in idiopathic dilated cardiomyopathy (IDC). Besides several other factors (increased wall stress, endothelial dysfunction, decreased coronary reserve), the observed decreased capillarisation in IDC, disproportionate to the rate of hypertrophy, may further contribute to this oxygen demand–supply mismatch. The reason for this seemingly decreased angiogenic capacity remains unclear, however a role for microvascular abnormalities in heart failure is now recognised. Hypoxia is the key factor in the induction of vascular endothelial growth factor (VEGF). Increased expression of VEGF causes angiogenesis, and expression level of VEGF could therefore mediate the capillarisation in IDC. Recently, data have been reported on this issue, and the authors found a downregulation of VEGF165 and VEGF189 isoforms. The VEGF121 however was not investigated, although it has been suggested that this isoform in particular has powerful angiogenic capacities. Additionally, it is unclear whether VEGF expression is related to the severity of the disease.