Multimodal optical and Gd-based nanoparticles for imaging in inflammatory arthritis

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Rheumatology

Background:

• Inflammatory arthritis, such as collagen-induced arthritis (CIA), affects joint health.
• Accurate imaging of inflamed synovium is crucial for diagnosis and monitoring.
• Current contrast agents may have limitations in dual-modality applications.

Purpose of the Study:

• To evaluate a multimodal nanoparticle (MNP) contrast agent for imaging inflamed synovium in a CIA model.
• To assess the dual-modality capabilities (optical and magnetic resonance) of MNPs.
• To determine the cellular localization and correlation with disease severity.

Main Methods:

• DBA-1J mice were induced with CIA and subsequently imaged.
• Intravenous administration of MNPs followed by optical and magnetic resonance imaging.
• Clinical scoring, immunofluorescence, and confocal microscopy were performed on hindlimb sections.

Main Results:

• MNP optical luminescence correlated with disease severity in a dose-dependent manner.
• Immunofluorescence confirmed MNP localization to monocytes/macrophages within the inflamed synovium.
• Magnetic resonance imaging showed decreased T2 signal in inflamed joints, more pronounced earlier in disease.

Conclusions:

• MNPs with embedded luminophores and gadolinium chelates act as effective dual-modality contrast agents.
• These MNPs specifically target monocytes/macrophages in the inflamed synovium.
• MNPs show potential for diagnosing and monitoring inflammatory arthritis.