Experimental arteriosclerosis. I. Fibrous plaque formation in primates, an electron microscope study

Area of Science:

• Vascular biology
• Pathology
• Atherosclerosis research

Background:

• Arteriosclerosis involves complex cellular and molecular changes in blood vessels.
• Understanding the early stages of lesion formation is crucial for developing effective treatments.
• Animal models are essential for studying the pathogenesis of vascular diseases.

Purpose of the Study:

• To investigate the development and potential reversibility of arteriosclerotic lesions in non-human primates.
• To elucidate the role of vascular endothelium injury in smooth muscle cell migration and proliferation.
• To establish a relevant animal model for studying preatherosclerotic intimal hyperplasia.

Main Methods:

• Induction of arteriosclerotic lesions in Macaca nemestrina monkeys using an intra-arterial balloon catheter to selectively remove vascular endothelium.
• Monitoring of lesion development and vascular repair over time (up to 6 months).
• Histological analysis to characterize cellular changes, extracellular matrix deposition, and lesion morphology.

Main Results:

• De-endothelialization triggered immediate platelet aggregation, followed by re-endothelialization within 7 days.
• Smooth muscle cells migrated into the intima and proliferated starting day 4, forming hyperplastic lesions by 28 days.
• Lesions showed significant regression by 6 months in the absence of continued injury, indicating potential reversibility.

Conclusions:

• Endothelial injury is a critical factor initiating smooth muscle cell migration and proliferation, leading to intimal lesion formation.
• The observed lesions closely resemble human fibromusculo-elastic lesions and preatherosclerotic intimal hyperplasia.
• This primate model provides a valuable tool for further research into atherosclerosis pathogenesis and therapeutic strategies.