In vivo fluorescence imaging of E‐selectin: Quantitative detection of endothelial activation in a mouse model of arthritis

Abstract

Objective. In vivo optical imaging can delineate at the macroscopic level processes that are occurring at the cellular and molecular levels. E-selectin, a leukocyte adhesion molecule expressed on endothelium, is induced by tumor necrosis factor ␣ (TNF␣) and other cytokines involved in the pathogenesis of rheumatoid arthritis (RA). Collagen-induced arthritis (CIA) in mice is widely used to study the disease mechanisms and identify new treatments for RA. The purpose of this study was to demonstrate E-selectin-targeted fluorescence imaging in vivo in a mouse model of paw edema generated by local injection of TNF␣ as well as in mice with CIA.Methods. Animals with either CIA or TNF␣-induced paw edema were injected with anti-E-selectin or control antibodies labeled with a DyLight 750-nm near-infrared (NIR) probe. In vivo imaging studies were undertaken using an NIR optical imaging system, and images were coregistered with plain radiographic images.Results. The mean fluorescence intensity measured over the time-course of TNF␣-induced edema demonstrated a 1.97-fold increase (P < 0.001) in signal in inflamed paws at 8 hours following injection of anti-E-selectin antibody, as compared to that in the isotype control. In the CIA model, a 2.34-fold increase in E-selectin-targeted signal was demonstrated (P < 0.01). Furthermore, significant E-selectin-targeted signal was observed in the paws of animals immunized with collagen that did not display overt signs of arthritis.Conclusion. E-selectin-targeted fluorescence in vivo imaging is a quantifiable method of detecting endothelial activation in arthritis and can potentially be applied to the quantification of disease and the investigation of the effects of new therapies. Importantly, this approach may also be useful for the detection of subclinical disease in RA.

Alarmin S100A8/S100A9 as a biomarker for molecular imaging of local inflammatory activity

“…In CIA, E-selectin-targeted optical imaging has been demonstrated to reflect inflammatory activity with similar SNR to our data29. Interestingly, S100A9 has been shown to induce the expression of E-selectin in endothelial cells30, indicating that both methods address different target cells within closely linked inflammatory mechanisms.…”

SPECT Imaging of Joint Inflammation with Nanobodies Targeting the Macrophage Mannose Receptor in a Mouse Model for Rheumatoid Arthritis

“…In addition, 64 Cu antibodies were able to visualize glucose-6-phosphate isomerase in joints of mice from the K/BxN mouse model of arthritis using small-animal PET (28). More specific attention was paid to markers associated with inflammatory conditions in studies using near-infrared antibody-guided imaging to visualize E-selectin (29), present on activated endothelium, and F4/80 (30), present on macrophages and eosinophils. Furthermore, Turk et al demonstrated accumulation of activated macrophages in joints of rats with adjuvant-induced arthritis by g-scintigraphy using folic acid-99m Tc conjugates, which bind to the high-affinity folate receptor (31).…”

Molecular imaging of rheumatoid arthritis: emerging markers, tools, and techniques

“…These mechanisms commence early in the pathogenesis of arthritis. Fluorescently labeled anti-E-selectin antibodies were successfully used for imaging in a mouse model for RA, enabling detection of subclinical manifestations, monitoring effects of therapy, and quantification of disease [61]. In patients with RA, 99m Tc-anti-E-selectin-Fab appeared to be suitable for scintigraphic imaging of synovitis and showed a higher specificity than 99m Tc- hydroxymethylene diphosphonate bone imaging [60].…”