Development of targeted angiogenic medicine

Strategies to alter angiogenesis have been successfully translated from the bench to bedside. With an estimated number of more than 500 million patients worldwide potentially benefiting from it, it is a prime example of targeted therapy that is increasingly changing the face of clinical medicine. Most efforts to stimulate or inhibit angiogenesis in the past were focused on the key angiogenic factor vascular endothelial growth factor (VEGF), resulting in the approval by the Food and Drug Administration of several drugs for the treatment of cancer and ocular disease. However, mounting clinical evidence reveals that inhibition of VEGF causes resistance and class-specific side effects, while therapeutic angiogenesis by delivering VEGF protein is more challenging than anticipated in human patients. Hence, alternatives are needed, and modulation of oxygen-sensitive enzymes (prolyl hydroxylase domain proteins) and of hypoxia induced transcription factors has recently emerged as a potential novel strategy to treat cancer and ischemic diseases. Furthermore, placental growth factor is a disease-specific angiogenic target, whose inhibition reduces cancer growth without causing major side effects, while its delivery induces revascularization of ischemic tissues. In this review, we summarize recent developments and discuss questions that arise in the exciting, rapidly developing field of angiogenic medicine, including a brief description of its possible implications in neurodegenerative diseases.