In-vivo confocal real-time mini-microscopy in animal models of human inflammatory and neoplastic diseases

Background and study aims: Although various improvements in tissue imaging modalities have recently been achieved, in-vivo molecular and subsurface imaging in the field of gastroenterology remains a technical challenge. In this study we evaluated a newly developed, handheld, miniaturized confocal laser microscopy probe for realtime in-vivo molecular and subsurface imaging in rodent models of human disease. Materials and methods: The minimicroscope uses a 488-nm, single line laser for fluorophore excitation. The optical slice thickness is 7 mu m, the lateral resolution 0.7 mu m. The range of the z-axis is 0 - 250 mu m below the tissue surface. Imaging was performed using different fluorescent staining protocols; 5-carboxyfluorescein-labeled octreotate was synthesized for targeted molecular imaging. Results: Cellular and subcellular details of the gastrointestinal tract could be visualized in vivo at high resolution. Confocal real-time microscopy allowed in-vivo identification of tumor vessels and liver metastases, as well as diagnosis of focal hepatic inflammation, necrosis, and associated perfusion anomalies. Somatostatin-receptor targeting permitted in-vivo molecular staining of AR42-J-induced carcinoma and pancreatic islet cells. Conclusions: Confocal mini-microscopy allows rapid in-vivo molecular and subsurface imaging of normal and pathological tissue in the gastrointestinal tract at high resolution. Because this technology is applicable to humans, it might impact on future in-vivo microsocpic and molecular diagnosis of diseases such as cancer and inflammation.