Angiogenesis is the process by which your body grows new blood vessels from existing ones. It happens throughout your life, from embryonic development to wound healing, and plays a central role in both health and disease. When angiogenesis works correctly, it delivers oxygen and nutrients to tissues that need them. When it goes wrong, it can fuel cancer growth, cause vision loss, or contribute to chronic disease.
How New Blood Vessels Form
Your body builds new blood vessels through a tightly coordinated sequence. It starts when cells in an area become starved of oxygen. Those oxygen-deprived cells release signaling proteins, the most important being VEGF (vascular endothelial growth factor). VEGF acts like a chemical beacon, attracting the cells that line nearby blood vessels and telling them to start dividing and migrating toward the signal.
The cells lining your blood vessels, called endothelial cells, respond by proliferating, stretching outward, and forming tiny tubes. These tubes eventually connect, mature, and become functional blood vessels capable of carrying blood. The whole process is governed by a balance between pro-angiogenic signals (like VEGF) that encourage vessel growth and anti-angiogenic signals that keep it in check. Your body naturally produces inhibitors like endostatin, angiostatin, and thrombospondin-1, all of which act as brakes on vessel formation. When the balance tips too far in either direction, problems arise.
When Your Body Needs New Blood Vessels
Healthy angiogenesis is essential at several points in life. During embryonic development, it builds the entire circulatory system from scratch. In adults, it kicks in during wound healing: when you cut your skin, new vessels sprout to deliver immune cells and nutrients to the injury site. In women, angiogenesis occurs monthly as the uterine lining rebuilds during the menstrual cycle. It also drives placental development during pregnancy, ensuring the growing fetus receives adequate blood supply.
Outside of these situations, angiogenesis in healthy adults is relatively quiet. Most blood vessels in your body are stable and long-lived. This is why abnormal angiogenesis, either too much or too little, is such a reliable marker of disease.
The Angiogenic Switch in Cancer
Cancer’s relationship with angiogenesis is one of the most significant discoveries in modern oncology. In 1970, surgeon Judah Folkman proposed that tumors depend on new blood vessel growth to survive and spread. The idea was initially met with skepticism, but it has since transformed cancer treatment.
Here’s how it works: a small cluster of cancer cells can survive on its own only up to a point. Without a dedicated blood supply, a tumor cannot grow beyond roughly 100 to 500 microns (smaller than a grain of sand) because oxygen and nutrients can’t diffuse any further from the nearest capillary. Many early-stage tumors remain in this dormant state for years. Prostatic intraepithelial neoplasia, for instance, is found in about 16% of men who undergo prostate biopsies, and these growths may never progress.
The turning point, called the “angiogenic switch,” occurs when tumor cells begin releasing large amounts of VEGF and other growth factors. As cancer cells at the center of a growing mass become starved of oxygen, they ramp up production of these signals. New blood vessels sprout toward the tumor, delivering the nutrients it needs to expand aggressively. These new vessels don’t just feed the tumor. They also provide an escape route: cancer cells can enter the newly formed blood vessels and travel to distant organs, which is how metastasis begins. In general, the more blood vessels a tumor develops, the greater the chance that cancer cells will break away and spread.
Angiogenesis and Vision Loss
The same process that feeds tumors can also destroy eyesight. In wet age-related macular degeneration (wet AMD), abnormal blood vessels grow beneath the retina from the choroid layer underneath. These vessels are fragile and leak fluid, which disrupts the delicate layers of the macula responsible for sharp central vision. The result is swelling, tissue damage, and sometimes focal retinal detachment.
Wet AMD accounts for roughly 10 to 25% of people with early signs of macular degeneration, but it causes far more severe and rapid vision loss than the dry form. Without treatment, about 16% of people who develop wet AMD become legally blind within two years. Treatments that block VEGF, delivered as injections into the eye, have dramatically improved outcomes by starving the abnormal vessels of their growth signals.
Anti-Angiogenic Cancer Treatments
The realization that tumors need blood vessels to grow led to an entirely new class of cancer drugs. These medications work by blocking the signals that drive vessel formation, essentially cutting off the tumor’s supply lines. Most target VEGF or the receptors it binds to on endothelial cells.
Over a dozen anti-angiogenic drugs are now on the market. They fall into two broad categories. Some, like ramucirumab and aflibercept, directly trap or block VEGF before it can reach its target. Others are small molecules that interfere with the internal signaling machinery of endothelial cells. Drugs like sunitinib, sorafenib, and lenvatinib block multiple growth factor receptors simultaneously, which makes it harder for tumors to find alternative pathways to build blood vessels. These treatments are used across a range of cancers, including kidney, liver, thyroid, and colorectal cancers.
Anti-angiogenic drugs typically don’t cure cancer on their own. They’re most effective when combined with other treatments like chemotherapy or immunotherapy, slowing tumor growth and making other therapies more effective.
Promoting Angiogenesis for Heart Disease
While blocking blood vessel growth is the goal in cancer and eye disease, the opposite strategy is being pursued for heart disease. When coronary arteries become blocked, parts of the heart muscle are starved of oxygen. Therapeutic angiogenesis aims to coax the body into growing new vessels around the blockage, restoring blood flow without surgery.
Clinical trials have tested several approaches, including injecting VEGF directly into heart tissue and transplanting bone marrow-derived cells that can stimulate vessel growth. Results have been mixed but encouraging. In one approach, delivering VEGF via a viral carrier into heart muscle during a coronary procedure improved blood flow to the affected area. Bone marrow cell therapies have shown safety and, in some trials, meaningful improvements in heart function. A phase III study called RENEW found that injecting certain stem cells into the heart muscle improved exercise tolerance and reduced chest pain frequency in patients with chronic blockages.
These strategies remain largely experimental, and single-therapy approaches have produced modest results. Researchers believe combining multiple growth factors or cell types will be necessary to achieve consistent, clinically meaningful benefits.
Diet and Natural Angiogenesis Regulation
Several compounds found in everyday foods have shown the ability to influence angiogenesis in laboratory and animal studies. These aren’t replacements for medical treatment, but the research is noteworthy for understanding how diet intersects with blood vessel biology.
Genistein, found in soy products, has been shown to inhibit VEGF signaling in endothelial cells and simultaneously boost the body’s own anti-angiogenic proteins, including endostatin, angiostatin, and thrombospondin-1. EGCG, the primary active compound in green tea, and resveratrol, found in red grapes and berries, have both demonstrated effects on cancer stem cell populations and angiogenic pathways in lab settings. Quercetin, present in onions, apples, and berries, affects endothelial cell proliferation and migration and reduces the activity of enzymes that tumors use to break through surrounding tissue during vessel formation.
The gap between laboratory results and real-world dietary effects remains significant. Concentrations used in cell and animal studies are often much higher than what you’d get from food alone. Still, these findings add biological plausibility to the broader evidence linking plant-rich diets with lower cancer risk.