Arteriogenesis versus angiogenesis: similarities and differences

Area of Science:

• Cardiovascular Biology
• Vascular Biology
• Regenerative Medicine

Background:

• Cardiovascular diseases are a leading cause of mortality globally.
• Therapies promoting blood vessel growth offer an alternative to surgery.
• Blood vessel growth occurs via angiogenesis (hypoxia-driven) and arteriogenesis (shear stress-driven).

Purpose of the Study:

• To investigate the mechanisms of blood vessel growth, focusing on the role of circulating cells.
• To challenge the traditional view of structural integration of cells into vessel walls.

Main Methods:

• Review of existing literature on angiogenesis and arteriogenesis.
• Analysis of studies implicating circulating cells, particularly monocytes/macrophages, in vascular repair.
• Evaluation of evidence regarding the contribution of bone-marrow derived stem cells and endothelial progenitors.

Main Results:

• Arteriogenesis, driven by fluid shear stress, involves remodeling of existing vessels.
• Circulating monocytes and macrophages contribute to vascular growth primarily through paracrine signaling (releasing growth factors, chemokines, proteases).
• Evidence increasingly challenges the hypothesis that circulating cells structurally integrate into growing vessel walls.

Conclusions:

• The role of circulating cells, especially monocytes, in vascular growth is predominantly paracrine, not structural.
• Understanding these paracrine mechanisms is crucial for developing novel pro-angiogenic therapies.
• Future research should focus on the signaling pathways involved in cell-mediated vascular repair.