Journal Article

Adenocarcinoma/*diagnosis; Animals; Colonic Neoplasms/*diagnosis; Contrast Media/pharmacokinetics; Disease Models, Animal; Female; Fluorescent Dyes/pharmacokinetics; Gold/pharmacokinetics; Image Processing, Computer-Assisted; Indocyanine Green/pharmacokinetics; Mammary Neoplasms, Experimental/*diagnosis; Mice; Nanoparticles; Spectrum Analysis/methods; Tomography, Optical/*methods

PURPOSE: To investigate whether multispectral optoacoustic tomography (MSOT) can reveal the heterogeneous distributions of exogenous agents of interest and vascular characteristics through tumors of several millimeters in diameter in vivo. MATERIALS AND METHODS: Procedures involving animals were approved by the government of Upper Bavaria. Imaging of subcutaneous tumors in mice was performed by using an experimental MSOT setup that produces transverse images at 10 frames per second with an in-plane resolution of approximately 150 mum. To study dynamic contrast enhancement, three mice with 4T1 tumors were imaged before and immediately, 20 minutes, 4 hours, and 24 hours after systemic injection of indocyanine green (ICG). Epifluorescence imaging was used for comparison. MSOT of a targeted fluorescent agent (6 hours after injection) and hemoglobin oxygenation was performed simultaneously (4T1 tumors: n = 3). Epifluorescence of cryosections served as validation. The accumulation owing to enhanced permeability and retention in tumors (4T1 tumors: n = 4, HT29 tumors: n = 3, A2780 tumors: n = 2) was evaluated with use of long-circulating gold nanorods (before and immediately, 1 hour, 5 hours, and 24 hours after injection). Dark-field microscopy was used for validation. RESULTS: Dynamic contrast enhancement with ICG was possible. MSOT, in contrast to epifluorescence imaging, showed a heterogeneous intratumoral agent distribution. Simultaneous imaging of a targeted fluorescent agent and oxy- and deoxyhemoglobin gave functional information about tumor vasculature in addition to the related agent uptake. The accumulation of gold nanorods in tumors seen at MSOT over time also showed heterogeneous uptake. CONCLUSION: MSOT enables live high-spatial-resolution observations through tumors, producing images of distributions of fluorochromes and nanoparticles as well as tumor vasculature.

Journal Article

IntegriSense,Animals; Fluorescent Dyes/metabolism; Humans; Nanoparticles/diagnostic use; Optics and Photonics/*methods; Surgery, Computer-Assisted/*methods

In cancer surgery, intra-operative assessment of the tumor-free margin, which is critical for the prognosis of the patient, relies on the visual appearance and palpation of the tumor. Optical imaging techniques provide real-time visualization of the tumor, warranting intra-operative image-guided surgery. Within this field, imaging in the near-infrared light spectrum offers two essential advantages: increased tissue penetration of light and an increased signal-to-background-ratio of contrast agents. In this article, we review the various techniques, contrast agents, and camera systems that are currently used for image-guided surgery. Furthermore, we provide an overview of the wide range of molecular contrast agents targeting specific hallmarks of cancer and we describe perspectives on its future use in cancer surgery.

Journal Article

IntegriSense

A key aspect for the postoperative prognosis of patients with head and neck cancer is complete tumor resection. In current practice, the intraoperative assessment of the tumor-free margin is dependent on visual appearance and palpation of the tumor. Optical imaging has the potential of traversing the gap between radiology and surgery by providing real-time visualization of the tumor, thereby allowing for image-guided surgery. The use of the near-infrared light spectrum offers 2 essential advantages: increased tissue penetration of light and an increased signal-to-background ratio of contrast agents. In this review, the current practice and limitations of image-guided surgery by optical imaging using intrinsic fluorescence or contrast agents are described. Furthermore, we provide an overview of the various molecular contrast agents targeting specific hallmarks of cancer that have been used in other fields of oncologic surgery, and we describe perspectives on its future use in head and neck cancer surgery.

Journal Article

IntegriSense, Animals; Bronchoalveolar Lavage Fluid/chemistry; Ceramides/metabolism; Female; Gene Deletion; Gene Expression Regulation/physiology; Lung/*radiation effects; Lysophospholipids/*chemistry/*pharmacology; Mice; Mice, Inbred C57BL; Mice, Knockout; *Radiation Injuries, Experimental; Receptors, Lysosphingolipid/genetics/metabolism; Sphingolipids/*metabolism; Sphingosine/*analogs & derivatives/chemistry/pharmacology

Clinically significant radiation-induced lung injury (RILI) is a common toxicity in patients administered thoracic radiotherapy. Although the molecular etiology is poorly understood, we previously characterized a murine model of RILI in which alterations in lung barrier integrity surfaced as a potentially important pathobiological event and genome-wide lung gene mRNA levels identified dysregulation of sphingolipid metabolic pathway genes. We hypothesized that sphingolipid signaling components serve as modulators and novel therapeutic targets of RILI. Sphingolipid involvement in murine RILI was confirmed by radiation-induced increases in lung expression of sphingosine kinase (SphK) isoforms 1 and 2 and increases in the ratio of ceramide to sphingosine 1-phosphate (S1P) and dihydro-S1P (DHS1P) levels in plasma, bronchoalveolar lavage fluid, and lung tissue. Mice with a targeted deletion of SphK1 (SphK1(-/-)) or with reduced expression of S1P receptors (S1PR1(+/-), S1PR2(-/-), and S1PR3(-/-)) exhibited marked RILI susceptibility. Finally, studies of 3 potent vascular barrier-protective S1P analogs, FTY720, (S)-FTY720-phosphonate (fTyS), and SEW-2871, identified significant RILI attenuation and radiation-induced gene dysregulation by the phosphonate analog, fTyS (0.1 and 1 mg/kg i.p., 2x/wk) and to a lesser degree by SEW-2871 (1 mg/kg i.p., 2x/wk), compared with those in controls. These results support the targeting of S1P signaling as a novel therapeutic strategy in RILI.

Journal Article

IntegriSense, Angiogenesis Inhibitors/therapeutic use; Animals; Diagnostic Imaging/*methods; Fluorescence; Humans; Luminescence/diagnostic use; Magnetic Resonance Angiography/methods; Magnetic Resonance Imaging/methods; Microscopy/methods; Neoplasms/*blood supply/therapy; *Neovascularization, Pathologic/pathology/ultrasonography; Positron-Emission Tomography/methods; Tomography/methods; Tomography, Emission-Computed, Single-Photon/methods; Tomography, X-Ray Computed/methods; X-Ray Microtomography/methods

Significant advances have been made in understanding the role of tumor angiogenesis and its influence on tumor progression in cancer. Based on this knowledge, a series of inhibitors of angiogenesis have been developed and evaluated in preclinical and clinical trials. Since detailed information of tumor progression in response to therapy is important to assess the efficacy of anti-tumor treatment in vivo, noninvasive imaging techniques emerge more and more as important tools to monitor alterations in tumor growth and vessel recruitment, as well as metastatic spread over time. So far, remarkable efforts have been made to improve the technical capability of these imaging modalities based on better resolution, as well as to implement multimodal approaches combining molecular with anatomical information. Advanced imaging techniques not only allow the detection and monitoring of tumor development, but also facilitate a broad understanding of the cellular and molecular events that propagate tumor angiogenesis, as well as those occurring in response to therapy. This review provides an overview of different imaging techniques in preclinical settings of oncological research and discusses their potential impact on clinical translation. Imaging modalities will be presented that have been implemented to address key biological issues by exploring tumor angiogenic processes and evaluating antiangiogenic therapy.