Circulating endothelial progenitor cells do not contribute to plaque endothelium in murine atherosclerosis

Area of Science:

• Cardiovascular Biology
• Cell Biology
• Atherosclerosis Research

Background:

• Endothelial progenitor cells (EPCs) are proposed to aid arterial repair after injury.
• The role of circulating EPCs in atherosclerosis, a major arterial disease, remains unclear.
• This study investigates EPC contribution to plaque endothelium in a mouse model.

Purpose of the Study:

• To determine if circulating EPCs contribute to plaque endothelium during atherogenesis.
• To assess EPC involvement in reendothelialization after plaque disruption.

Main Methods:

• Utilized lethally irradiated apolipoprotein E-deficient (apoE(-/-)) mice reconstituted with enhanced green fluorescent protein (eGFP) transgenic bone marrow.
• Examined carotid artery plaques and mechanically disrupted plaques using high-resolution microscopy.
• Employed sex-mismatched transplants and Y chromosome tracking for cell origin analysis.

Main Results:

• Only 1 eGFP+ endothelial cell was identified among 4232 analyzed in atherosclerotic plaques.
• Similarly, only 1 eGFP+ endothelial cell was found among 3170 analyzed after plaque disruption.
• Cell tracking confirmed a very low contribution of circulating EPCs to plaque endothelium.

Conclusions:

• Circulating EPCs seldom contribute to plaque endothelium in apoE(-/-) mice.
• These findings question the established theory of EPCs' significant role in atherogenesis.
• The study suggests limited therapeutic potential for circulating EPCs in treating atherosclerosis.