CD11b-Based Pre-Targeted SPECT/CT Imaging Allows for the Detection of Inflammation in Aortic Aneurysm

Area of Science:

• Biomedical imaging
• Molecular imaging
• Radiochemistry

Background:

• Inflammatory aortic aneurysm (AA) is a serious condition.
• Accurate imaging of CD11b expression is crucial for assessing AA inflammation.
• Current imaging methods may have limitations in sensitivity and specificity.

Purpose of the Study:

• To evaluate a pre-targeted imaging strategy for detecting CD11b expression in AA.
• To utilize the cycloaddition reaction between 1,2,4,5-terazine (Tz) and trans-cyclooctene (TCO).
• To employ single photon emission computed tomography/computed tomography (SPECT/CT) for in vivo imaging.

Main Methods:

• AA models were established in C57BL/6J mice.
• Anti-CD11b-TCO and 99mTc-HYNIC-PEG11-Tz probes were synthesized.
• In vitro affinity and specificity of probes were assessed.
• Pre-targeted SPECT/CT was performed in vivo.
• Ex vivo analyses included gamma imaging, Western blot, and immunohistochemistry.

Main Results:

• The pre-targeting strategy successfully identified inflammatory AA in mice.
• High AA-to-background ratios were achieved with the pre-targeted SPECT/CT.
• In vitro and in vivo probe characteristics demonstrated high efficiency and specificity.
• Ex vivo results confirmed the SPECT/CT findings.

Conclusions:

• The developed anti-CD11b-TCO/Tz-PEG11-HYNIC-99mTc pre-targeting imaging strategy is feasible.
• This method enables effective detection of inflammation in progressive AA.
• This approach holds promise for future diagnostic applications in AA.