Difference Between Angiogenesis and Neovascularization

The key difference between angiogenesis and neovascularization is that angiogenesis primarily refers to the formation of new blood vessels from pre-existing blood vessels, while neovascularization is the process of de novo formation of blood vessels or formation of new blood vessels from pre-existing blood vessels.

Angiogenesis and neovascularization are two terms related to the formation of new blood vessels. Angiogenesis is the formation of new blood vessels from pre-existing blood vessels. Neovascularization, on the other hand, is the natural formation of new blood vessels through mechanisms such as de novo formation of blood vessels or the formation of new blood vessels from pre-existing blood vessels. Remodelling of existing vasculature to create collateral arteries can also be explained as a type of neovascularization process.

CONTENTS

1. Overview and Key Difference
2. What is Angiogenesis 
3. What is Neovascularization
4. Similarities Between Angiogenesis and Neovascularization
5. Side by Side Comparison – Angiogenesis vs Neovascularization in Tabular Form
6. Summary

What is Angiogenesis?

Angiogenesis is the most common type of new blood vessel formation during growth and development. Angiogenesis takes place through the formation of new vessels from pre-existing vessels. This process occurs through the sprouting of new capillaries from post-capillary venules. It requires precise coordination of multiple steps. This process involves multiple cell types participating and communicating.

This complex process is initiated by the local response to tissue ischemia or hypoxia. It leads to realising of angiogenic factors such as vascular endothelial growth factor (VEGF) and hypoxia-inducible factors (HIFs). The vascular endothelial growth factor is a signal protein produced by fibroblast, which stimulates the formation of new blood vessels. Hypoxia-inducible factors are transcription factors that respond to the reduction in available oxygen in the cellular environment. And, releasing these factors leads to vasodilation and increased vascular permeability. This process stimulates either sprouting angiogenesis or intussusceptive angiogenesis.

Angiogenesis is a normal vital process in growth and development. It also helps in wound healing and in the formation of granulation tissue. However, it is also the fundamental step to the transition of benign cancer to a malignant one. Scientists use angiogenesis inhibitors in the treatment of cancer.

What is Neovascularization?

Neovascularization is a natural process of forming new blood vessels in the body through both de novo formation and pre-existing blood vessels. The term vasculogenesis is the de novo formation of new blood vessels. This primarily takes place in developing embryos, but it also occurs with post-natal vascularization. Neovascularization comprises three different pathways: vasculogenesis, angiogenesis, and arteriogenesis. Angiogenesis is the most typical type of neovascularization observed in development and growth. The process of flow-related remodelling of existing vasculature to create collateral arteries is known as arteriogenesis.

The growth factors that inhibit neovascularization include those that affect the processes of endothelial cell division and differentiation. These growth factors can act as autocrine or paracrine methods. The above growth factors include fibroblast growth factor, placental growth factor, insulin-like growth factor, hepatocyte growth factor and platelet-derived endothelial growth factor.

What are the Similarities Between Angiogenesis and Neovascularization?

• They are two mechanisms of new blood vessels formation.
• Both mechanisms are very important to distribute oxygen and nutrients throughout the body.
• Growth factors play a pivotal role in both processes
• Both processes may trigger cancers when they become abnormal.

What is the Difference Between Angiogenesis and Neovascularization?

Angiogenesis primarily refers to the formation of new blood vessels from pre-existing blood vessels. In contrast, neovascularization is the de novo formation of blood vessels or the formation of new blood vessels from pre-existing blood vessels. So, this is the key difference between angiogenesis and neovascularization. Furthermore, angiogenesis increases 2-3X increase in blood flow. In contrast, neovascularization increases more than a 20-30X increase in blood flow.

Moreover, the growth factors mainly involved in angiogenesis are vascular endothelial growth factor and hypoxia-inducible factors, while the growth factors involved in neovascularization are fibroblast growth factor, placental growth factor, insulin-like growth factor, hepatocyte growth factor and platelet-derived endothelial growth factor. Thus, this is another important difference between angiogenesis and neovascularization.

Below is a list of differences between angiogenesis and neovascularization in tabular form for side by side comparison.

Summary – Angiogenesis vs Neovascularization

Angiogenesis refers to the formation of new blood vessels from pre-existing blood vessels, while neovascularization is the natural formation of new blood vessels through mechanisms such as de novo formation of blood vessels or the formation of new blood vessels from pre-existing blood vessels. This is also a way of remodelling the existing vasculature to create collateral arteries. Thus, this is the summary of the difference between angiogenesis and neovascularization.

Reference:

1. “Angiogenesis.” Wikipedia, Wikimedia Foundation, 28 Feb. 2021, Available here.
2. “Neovascularization.” Wikipedia, Wikimedia Foundation, 14 Jan. 2021, Available here.

Image Courtesy:

1. “Angiogenesis 2” By Вячеслав Евдокимов – Own work (CC BY-SA 3.0) via Commons Wikimedia

2. “Choroidal neovascularization” By NIH Image Gallery (CC BY-NC 2.0) via Flickr