Citation Details

Journal Article

in vivo imaging; Tumor-associated macrophages

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Journal Article

ProSense; AngioSense; arthritis; in vivo imaging

OBJECTIVE: To test a novel self-activating viridin (SAV) prodrug that slowly releases wortmannin, a potent phosphoinositide 3-kinase inhibitor, in a model of antibody-mediated inflammatory arthritis.

METHODS: The SAV prodrug was administered to K/BxN mice or to C57BL/6 (B6) mice that had been injected with K/BxN serum. Ankle thickness was measured, and histologic changes were scored after a 10-day disease course (serum-transfer arthritis). Protease activity was measured by a near-infrared imaging approach using a cleavable cathepsin-selective probe. Further near-infrared imaging techniques were used to analyze early changes in vascular permeability after serum injection, as well as neutrophil-endothelial cell interactions. Neutrophil functions were assessed using an oxidative burst assay as well as a degranulation assay.

RESULTS: SAV prevented ankle swelling in mice with serum-transfer arthritis in a dose-dependent manner. It also markedly reduced the extent of other features of arthritis, such as protease activity and histology scores for inflammation and joint erosion. Moreover, SAV was an effective therapeutic agent. The underlying mechanisms for the antiinflammatory activity were manifold. Endothelial permeability after serum injection was reduced, as was firm neutrophil attachment to endothelial cells. Endothelial cell activation by tumor necrosis factor alpha was impeded by SAV, as measured by the expression of vascular cell adhesion molecule. Crucial neutrophil functions, such as generation of reactive oxygen species and degranulation of protease-laden vesicles, were decreased by SAV administration.

CONCLUSION: A novel SAV prodrug proved strongly antiinflammatory in a murine model of antibody-induced inflammatory arthritis. Its activity could be attributed, at least in part, to the inhibition of neutrophil and endothelial cell functions.

Journal Article

ProSense; FMT; fluorescence; tomography; proteases; lung; inflammation; in vivo imaging

Biomedical imaging has become an important tool in the study of “-omics” fields by allowing the noninvasive visualization of functional and molecular events using in vivo staining and reporter gene approaches. This capacity can go beyond the understanding of the genetic basis and phenotype of such respiratory conditions as acute bronchitis, adult respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and asthma and investigate the development of disease and of therapeutic events longitudinally and in unperturbed environments. Herein, we show how the application of novel quantitative optical imaging methods, using transillumination and fluorescence molecular tomography (FMT), can allow visualization of pulmonary inflammation in small animals in vivo. The results confirm prior observations using a protease-sensitive probe. We discuss how this approach enables in vivo insights at the system level as to the dynamic role of proteases in respiratory pathophysiology and their potential as therapeutic targets. Overall, the proposed imaging method can be used with a significantly wider range of possible targets and applications in lung imaging.

Journal Article

ProSense; AngioSense; AngioSpark; in vivo imaging; pancreatic cancer

BACKGROUND & AIMS: Surgical management of pancreatic cancer depends on tumor resectability and staging. This study evaluated a new in vivo technique, fiberoptic confocal fluorescence microscopy (FCFM), for detection and staging of pancreatic tumors in rats.

METHODS: FCFM was used with a protease-activated fluorescent marker (ProSense; VisEn Medical Inc, Woburn, MA) for in vivo imaging of solid organs (1.8-microm resolution) in a rat model of pancreatic ductal adenocarcinoma. A preliminary study described the FCFM rendering of normal and pathologic tissues. Subsequently, 2 double-blind studies compared FCFM to standard histology in (1) detection of tumors in rat models of cancer and controls and (2) detection of nodal involvement (splenic, celiac, mesenteric, and colic) 4, 5, and 6 weeks after tumor induction vs controls.

RESULTS: Tumor cells displayed a fluorescent ductal pattern compared with non-fluorescent normal pancreas or normal follicular pattern of lymph nodes (LNs). FCFM detected all the pancreatic tumors (1.7-mm mean diameter) and identified 23 LNs that contained metastases of 99 LNs examined. Standard histologic analyses resulted in 1 false-negative result in tumor detection and 2 false negatives in LN detection, whereas FCFM produced no false-negative results. Additional serial sectioning confirmed all tumors and 16 metastatic LNs; FCFM had a negative predictive value of 100% and a positive predictive value of 69.6%.

CONCLUSIONS: Real-time “virtual biopsy” using FCFM detects tumors and LN metastases with 100% sensitivity and 92.2% specificity in rats, making it a reliable technique for detection and staging of pancreatic cancer.

Journal Article

FMT; in vivo imaging; ProSense

Fluorescent molecular tomographic (FMT) imaging can noninvasively monitor molecular function in living animals using specific fluorescent probes. However, macroscopic imaging methods such as FMT generally exhibit low anatomical details. To overcome this, we report a quantitative technique to image both structure and function by combining FMT and magnetic resonance (MR) imaging. We show that FMT-MR imaging can produce three-dimensional, multimodal images of living mouse brains allowing for serial monitoring of tumor morphology and protease activity. Combined FMT-MR tumor imaging provides a unique in vivo diagnostic parameter, protease activity concentration (PAC), which reflects histological changes in tumors and is significantly altered by systemic chemotherapy. Alterations in this diagnostic parameter are detectable early after chemotherapy and correlate with subsequent tumor growth, predicting tumor response to chemotherapy. Our results reveal that combined FMT-MR imaging of fluorescent molecular probes could be valuable for brain tumor drug development and other neurological and somatic imaging applications.