Tropoelastin: A novel marker for plaque progression and instability.

Area of Science:

• Biomedical Imaging
• Cardiovascular Research
• Molecular Imaging

Background:

• Atherosclerosis is characterized by tropoelastin accumulation due to impaired elastogenesis.
• Current methods lack specificity for imaging tropoelastin in plaques.
• Tropoelastin imaging may reveal plaque progression and instability.

Purpose of the Study:

• To develop and validate gadolinium-labeled tropoelastin-specific magnetic resonance contrast agents (Gd-TESMAs).
• To assess the utility of Gd-TESMAs for imaging tropoelastin in animal models of atherosclerosis.
• To evaluate Gd-TESMAs for detecting plaque instability in human samples.

Main Methods:

• Peptide selection for tropoelastin targeting.
• In vitro characterization of probes (binding, relaxivity, biodistribution).
• In vivo MRI in ApoE-/- mice and rabbits with stable/rupture-prone plaques.
• Ex vivo MRI of human carotid endarterectomy specimens.

Main Results:

• The selected Gd-TESMA probe specifically targeted tropoelastin.
• In vivo MRI showed increased vascular enhancement and R1 relaxation rate with atherosclerosis progression in mice.
• Gd-TESMA detected rupture-prone plaques in rabbits with high sensitivity and specificity.
• Ex vivo imaging confirmed tropoelastin-specific uptake in human plaques.

Conclusions:

• MRI of tropoelastin using Gd-TESMAs is a promising novel biomarker.
• This technique can non-invasively assess atherosclerotic plaque progression.
• Gd-TESMA imaging may aid in identifying vulnerable plaques for intervention.