Low-Dose Molecular Ultrasound Imaging with E-Selectin-Targeted PBCA Microbubbles

Area of Science:

• Biomedical Engineering
• Molecular Imaging
• Oncology

Background:

• E-selectin is a key marker in tumor angiogenesis and inflammation.
• Molecular ultrasound imaging offers a non-invasive method for detecting molecular targets.
• Poly n-butyl cyanoacrylate (PBCA)-shelled microbubbles (MBs) can be functionalized for targeted imaging.

Purpose of the Study:

• To determine the lowest diagnostically effective dose of E-selectin-targeted PBCA-shelled microbubbles.
• To evaluate the utility of these microbubbles for monitoring antiangiogenic therapy in cancer models.

Main Methods:

• E-selectin-targeted PBCA-shelled microbubbles were administered to mice with carcinoma xenografts.
• Microbubble dosage was systematically reduced to identify the minimum effective dose using ultrasound.
• Enzyme-linked immunosorbent assay (ELISA) and immunohistological analyses confirmed E-selectin expression and therapy effects.

Main Results:

• The minimum effective dose was determined to be 7 × 10^7 MBs/kg body weight.
• This dose enabled E-selectin detection in high-expressing tumors, with lower-expressing tumors requiring higher doses.
• A significant decrease in E-selectin binding was observed under antiangiogenic therapy, correlating with histological findings.

Conclusions:

• Molecular ultrasound imaging using E-selectin-targeted microbubbles is feasible at a dose of 7 × 10^7 MBs/kg.
• This approach effectively monitors antiangiogenic therapy response by assessing changes in E-selectin expression.
• Further improvements in targeting, microbubble composition, and detection methods could enhance sensitivity for clinical translation.