Fe(III) distribution varies substantially within and between atherosclerotic plaques

Area of Science:

• Cardiovascular Research
• Oxidative Stress Biology
• Medical Imaging and Diagnostics

Background:

• Vulnerable atherosclerotic plaques pose a rupture risk due to structural weakness, potentially linked to oxidative stress.
• Redox-active iron, specifically Fe(III), is implicated in oxidative stress mechanisms within plaques.

Purpose of the Study:

• To investigate the distribution of Fe(III) in carotid atherosclerotic plaques.
• To correlate Fe(III) levels with plaque vulnerability and rupture.

Main Methods:

• Atherosclerotic plaques from 10 patients (symptomatic and asymptomatic) were analyzed.
• Plaque vulnerability assessed via ultrasound and immunohistochemistry.
• Fe(III) quantified using electron paramagnetic resonance spectroscopy.

Main Results:

• Significant intra-plaque Fe(III) concentration variations were observed.
• Symptomatic plaques exhibited higher Fe(III) levels compared to asymptomatic ones (0.36 ± 0.21 vs. 0.06 ± 0.04 nmol Fe(III)/mg tissue).
• Symptomatic plaques showed increased cap rupture and macrophage infiltration (31% ± 11% vs. 2.3% ± 2.3%).

Conclusions:

• Fe(III) distribution is heterogeneous within atherosclerotic plaques.
• Higher Fe(III) concentrations correlate with symptomatic plaques, cap rupture, and increased macrophage activity.
• Fe(III) may serve as a biomarker for atherosclerotic plaque vulnerability.