Types of Angiogenesis
- Sprouting angiogenesis is the first identified form of angiogenesis and occurs in several stages.
- Intussusceptive angiogenesis involves splitting an existing blood vessel into two.
- Coalescent angiogenesis involves the fusion of capillaries to form larger blood vessels.
Physiology of Angiogenesis
- Mechanical stimulation of angiogenesis is not well characterised.
- Chemical stimulation involves angiogenic proteins and growth factors.
- Increased muscle contractions and nitric oxide produced during exercise may increase angiogenesis.
Angiogenic Factors
- FGF-2, FGF-1, and FGF-2 stimulate angiogenesis and wound healing.
- VEGF and VEGFR-2 play a major role in increasing the number of capillaries.
- Angiopoietins Ang1 and Ang2 are required for the formation of mature blood vessels.
- MMPs are involved in the degradation of proteins during angiogenesis.
Regulation of Angiogenesis
- Dll4 negatively regulates angiogenesis and inhibiting its signaling hinders endothelial cell proliferation and sprouting.
- Class 3 semaphorins (SEMA3s) modulate endothelial cell behavior and VEGF signaling.
- The relative expression levels of SEMA3s and VEGF-A are important for angiogenesis.
Applications and Implications
- Angiogenesis is a therapeutic target for diseases characterised by poor vascularization or abnormal vasculature.
- Tumor angiogenesis is necessary for tumor growth and can be targeted for antiangiogenic therapy.
- Angiogenesis is important in cardiovascular disease, exercise, macular degeneration, and tissue engineering.
- Accurate quantification of angiogenesis is important for studying its role in various diseases and therapies.
Note: The content has been organised into comprehensive groups, combining identical concepts and keeping facts, statistics, and detailed points.
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature mainly by processes of sprouting and splitting, but processes such as coalescent angiogenesis, vessel elongation and vessel cooption also play a role. Vasculogenesis is the embryonic formation of endothelial cells from mesoderm cell precursors, and from neovascularization, although discussions are not always precise (especially in older texts). The first vessels in the developing embryo form through vasculogenesis, after which angiogenesis is responsible for most, if not all, blood vessel growth during development and in disease.
| Angiogenesis | |
|---|---|
 Angiogenesis following vasculogenesis | |
| Anatomical terminology |
Angiogenesis is a normal and vital process in growth and development, as well as in wound healing and in the formation of granulation tissue. However, it is also a fundamental step in the transition of tumors from a benign state to a malignant one, leading to the use of angiogenesis inhibitors in the treatment of cancer. The essential role of angiogenesis in tumor growth was first proposed in 1971 by Judah Folkman, who described tumors as "hot and bloody," illustrating that, at least for many tumor types, flush perfusion and even hyperemia are characteristic.
From angio- + -genesis.
angiogenesis (plural angiogeneses)
