Multimodal VEGF-Targeted Contrast-Enhanced Ultrasound and Photoacoustic Imaging of Rats with Inflammatory Arthritis: Using Dye-VEGF-Antibody-Loaded Microbubbles

Abstract

Owing to the heavy health burdens from rheumatoid arthritis, a sensitive and objective imaging method is needed for early diagnosis and accurate evaluation of the disease. We aimed to fabricate vascular epithelial growth factor (VEGF)Àtargeted microbubbles (MBs) to evaluate the expression levels of VEGF within the inflammatory lesions of rats with adjuvant-induced arthritis (AIA) using a multimodal photoacoustic (PA)/ ultrasound (US) imaging system. Fluorescein isothiocyanateÀbiotin double-labeled vascular endothelial growth factor receptor 2 antibodies and Cy5.5Àbiotin double-labeled VEGF2 antibodies were added to the avidinlabeled MBs to synthesize VEGF-targeted MBs. The antibodies could specifically bind to the MBs according to the flow cytometry and fluorescence imaging. In vitro experiments on the cellular uptake of the target MBs also validated the interaction of the VEGF antibodies and the MBs. Multimodal contrast-enhanced US (CEUS)/PA imaging was performed in sequence on the inflamed paws of the AIA rats with a single PA/US imaging system after the injection of the targeted MBs. The CEUS and PA signals were then quantified and verified by the pathologic results. A CEUS pattern of fast wash in and slow washout was observed in the AIA rats after injection of targeted MBs. Compared with AIA rats injected with unconnected VEGF antibodies and naked MBs, AIA rats injected with targeted MBs presented a higher peak intensity (p = 0.0079 and 0.0079 respectively) and a longer time to peak (p = 0.0117 and 0.0117, respectively). The PA signals were also significantly enhanced after injection of targeted MBs (p = 0.0112 and 0.0119, respectively), which was in accordance with the pathologic and immunohistochemical results. In conclusion, VEGF-targeted MBs can be used as agents for multimodal CEUS/PA imaging and to detect VEGF expression in the inflammatory lesions of AIA rats in vivo. This strategy may be useful in imaging evaluation of arthritis by identifying inflammation-related molecules in different imaging modes.

Looking deep inside tissue with photoacoustic molecular probes: a review

“… 274 Hence, efforts have been made to combine micro/nanobubbles with optical agents, so they can be used for dual-modal US/PA imaging. 261 , 275 For example, Zhao et al. 275 reported a dual-modal contrast agent that was composed of microbubbles loaded with vascular epithelial growth factor (VEGF) antibodies and fluorescent dyes.…”

“… 261 , 275 For example, Zhao et al. 275 reported a dual-modal contrast agent that was composed of microbubbles loaded with vascular epithelial growth factor (VEGF) antibodies and fluorescent dyes. As the expression level of VEGF in the synovial tissues of rheumatoid arthritis (RA) patients is very high, VEGF can be regarded as a specific biomarker for the RA disease.…”

Nanomaterials for Biomedical Applications: Production, Characterisations, Recent Trends and Difficulties

“…Nanobubbles can skip normal cells and expand the intracellular internalisation of the medication by the tumour cells. Likewise, they have an extra advantage of allowing imaging of the tumour by ultrasound techniques [49]. A successful trial for nanobubbles being used as carriers for doxorubicin as an anticancer drug on the basis of in vitro and in vivo studies was reported by Rapaport et al [50].…”

Optoacoustic Imaging in Inflammation

“…Similarly, Fournelle et al used an antitumor necrosis factor-α (TNF-α) antibody-coupled to gold nanorods as nanoprobes for confirming the overexpression of TNF-α in arthritic knees [ 87 ]. Instead of using nanoparticles, dye-VEGF-antibody-loaded microbubbles enabled multimodal OAI and US imaging of rats with inflammatory arthritis [ 88 ].…”