Endothelial Effects of VEGF Inhibition In Vivo in Man

Developments in chemotherapy have improved the prognosis for patients with cancer.1,2 Angiogenesis is essential for tumour growth and metastasis and vascular endothelial growth factor (VEGF) is fundamental to this process.3,4 Chemotherapeutic VEGF inhibitor (VEGFI) drugs have revolutionised therapy and improved the prognosis and survival of patients with previously untreatable malignancies.1,2 Blood pressure elevation is a common complication that occurs in up to 80% of patients treated with VEGFI and almost all patients have an absolute increase in blood pressure, with 30-60% developing frank hypertension.1,5 Patients are at risk of acute hypertensive complications, including stroke, acute coronary syndrome or reversible leukoencephalopathy and the development of VEGFI-associated hypertension may mandate the premature discontinuation of these important anti-cancer therapies. Those who survive their cancer are at risk of developing end-organ damage leading to ischaemic heart disease, heart failure, renal failure and stroke.1,5 Indeed, with substantially increased cancer survivorship patients often survive long enough to allow cardiovascular morbidity to take precedence over their initial cancer diagnosis. Mechanisms contributing to the development of VEGFI-associated hypertension may include endothelial dysfunction, capillary rarefaction and vascular remodelling.1,5 Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor and is strongly implicated in the pathogenesis of hypertension and endothelial dysfunction. 3,6,7 However, the effects of VEGFI on endothelial function and the role of ET-1 in VEGFI-associated hypertension are incompletely defined. Indeed, there is a paucity of information on mechanisms contributing to VEGFI-induced hypertension and our study will address this key issue.