Near-infrared Fluorescent Agent Research Articles

A Self-Assembled "Albumin-Conjugate" Nanoprobe for Near Infrared Optical Imaging of Subcutaneous and Metastatic Tumors.

The need for in situ accurate identification of tumor assisted real-time image-guided surgical resection calls for new near-infrared fluorescence agents with high tumor-sensitivity and excellent biocompatibility. Here, an albumin-conjugate nanoparticle system HSA-Er-RI-Cl was designed, synthesized, and applied in cancer imaging, which simultaneously achieved the EPR effect, hypoxia-targeting, and EGFR-targeting property. Our novel nanoprobe is composed of human serum albumin (HSA) and double-targeting small molecule conjugate (Er-RI-Cl): a hypoxia-targeting heptamethine carbocyanine dye (RI-Cl) conjugated with a clinic anti-EGFR antagonist (Erlotinib) by covalent bonding. This conjugate could bind to albumin proteins, forming albumin-conjugate complexes, and those complexes self-assemble into particles with diameters of approximately 100 nm in the aqueous solution. The tumor hypoxia and EGFR targeting specificity of HSA-Er-RI-Cl was, respectively, evaluated in vitro and in vivo. Using murine xenograft subcutaneous and brain metastatic tumor models, we demonstrated that HSA-Er-RI-Cl is a highly potent tumor-targeting NIR agent for noninvasive imaging with remarkable tumor localization and excellent pharmacokinetic properties.

P5 FEASIBILITY AND EFFICACY OF INDOCYANINE GREEN ANGIOGRAPHY DURING ESOPHAGECTOMY: A SYSTEMATIC REVIEW

Abstract Aim The aim of this review was to evaluate feasibility and effectiveness of Indocyanine green fluorescence angiography (ICGA) as an assessment tool for gastric tube (GT) perfusion during the construction of the esophago-gastric anastomosis, and as a predictor of anastomotic leakage (AL). Moreover, attention was given to attempts made to quantify this method in esophageal surgery. Background & Methods After an esophagectomy, a GT is most commonly used to restore continuity of the upper gastrointestinal tract. Esophago-gastric anastomoses are known for their complications such as AL, associated with high morbidity and mortality. Graft perfusion is an important predictor for anastomotic integrity. Tissue perfusion assessment is currently based on subjective parameters as tissue color and vessel pulsations. Near infrared fluorescent (NIRF) imaging is an emerging medical imaging modality, requiring penetrating NIR light that excites a NIRF agent within the tissue, generating fluorescence that can then be captured by adapted cameras. Indocyanine green Angiography (ICGA) is such a NIRF imaging technique which can be used as a method to visualize anastomotic perfusion. For this review, 2 reviewers independently searched Pubmed and Embase for studies evaluating intraoperative ICGA perfusion assessment of the GT. Feasibility, complications, intraoperative surgical changes based on ICGA findings, quantification attempts, anatomical data and the impact of ICGA on postoperative anastomotic complications were documented and further analyzed. Results Nineteen studies were included for qualitative analyses. All described ICGA as a safe and easy method for gastric graft perfusion assessment. AL occurred in 13.8% of the entire cohort, 10% in the ICG guided group and 20.6% in the control group (p<.001). AL in the well-perfused group was 6.3% vs. 20.5% in the control group without ICGA (p< .001). The group with an altered surgical plan based on the ICG image had similar AL rates as the well perfused group (6.5% vs. 6.3%) and significantly less than the poorly perfused group (47.8%) (p<.001), suggesting that the technique is able to identify and alter a potential bad outcome. Conclusion the present review suggest that ICGA is a safe and easy method for GT perfusion assessment. Differences in AL rate between the well perfused and poor perfused anastomotic sites suggest that a good fluorescent signal is a predictor of good outcome.

Transcutaneous Measurement of Glomerular Filtration Rate in Rodents.

Glomerular filtration rate (GFR) is considered the gold standard to test kidney function. However, the serial blood and/or urine sample collection required for the calculation of the GFR is stressful for the animal and time consuming for the experimenter. Here, we describe a transcutaneous assessment of renal function in conscious animals that does not require plasma or urine sampling and/or deep anesthesia. For the measurement, we use a near-infrared (NIR) device that records the excretion kinetic of the renal marker ABZWCY-HPβCD. ABZWCY-HPβCD is a new hydrophilic, stable, and nontoxic NIR fluorescent agent that can be used as a renal marker as it is filtrated and completely excreted through the kidneys into the urine without reabsorption or secretion and without accumulation in the skin. The data recorded in the device are then analyzed with "GFRmeasure," an open-source, freely downloadable, and user-friendly software.

A cationic near infrared fluorescent agent and ethyl-cinnamate tissue clearing protocol for vascular staining and imaging

Understanding vascular structures and dysfunction is a fundamental challenge. This task has been approached by using traditional methodologies such as microscopic computed tomography and magnetic resonance imaging. Both techniques are not only expensive but also time-consuming. Here, we present a new method for visualizing vascular structures in different organs in an efficient manner. A cationic near infrared (NIR) fluorescent dye was developed with attractive features to specifically stain blood vessels. Furthermore, we refined the process of organ staining and harvesting by retrograde perfusion and optimized the subsequent dehydration and clearing process by the use of an automatic tissue processor and a non-toxic substance, ethyl-cinnamate. Using this approach, the time interval between organ harvesting and microscopic analysis can be reduced from day(s) or weeks to 4 hours. Finally, we have demonstrated that the new NIR fluorescent agent in combination with confocal or light-sheet microscopy can be efficiently used for visualization of vascular structures, such as the blood vessels in different organs e.g. glomeruli in kidneys, with an extremely high resolution. Our approach facilitates the development of automatic image processing and the quantitative analysis to study vascular and kidney diseases.

Tumor-specific intraoperative detection of pancreatic ductal adenocarcinoma using multimodal molecular imaging

Background: Two major predictors of long term survival of pancreatic cancer are the ability to resect tumor with cancer free margins and absence of systemic metastases. Unfortunately, margin positive resections are a frequent phenomenon as is the emergence of distant metastases soon after surgery. The use of tumor targeted molecular imaging has the potential to provide crucial information to surgeon, both in the form of fluorescent and photoacoustic imaging. Here, we report the use of Cetuximab-IRDye800, a near-infrared fluorescent agent, that binds to EGFR for intraoperative detection of pancreatic cancer. Methods: A dose escalation study of Cetuximab conjugated to IRDye800 was performed in patients (n=7) undergoing surgical resection of pancreatic cancer. Safety and pharmacokinetic data were obtained up to 30 days after infusion. Multi-instrument fluorescence and photoacoustic imaging was performed both in the operating room and ex vivo. Results: There were no grade 2 or higher adverse events attributable to the intravenous injection of cetuximab-IRDye800. Fluorescence imaging successfully differentiated tumor and positive lymph nodes from normal tissue during resection with average tumor-to-background ratio of 8.7. Ex vivo fluorescence, photoacoustic and pathologic examination confirmed correlation between tumor and fluorescent and photoacoustic signal. Conclusion: This study demonstrates safety and feasibility of tumor-specific Cetuximab-IRDye800 for multimodal molecular intraoperative imaging of pancreatic cancer.

Development and preclinical validation of an Integrin αvβ6-targeting imaging agent for near-infrared fluorescent-guided surgery in pancreatic cancer

Background: Margin positive resections or early recurrence due to occult metastases after surgery of pancreatic ductal adenocarcinoma (PDAC) are common. Intraoperative near-infrared fluorescent (NIRF) imaging allows cancer visualization to improve surgical accuracy, however targeted agents are lacking. Integrin αvβ6 is a target specific for PDAC, able to detect positive lymph nodes and differentiate between pancreatitis and PDAC. We developed R01-MG-IRDye800, a clinically translatable αvβ6-targeting NIRF agent, based on a cysteine knot peptide, to visualize PDAC. Methods: The applicability of the tracer was tested for cell and tissue binding using cell-based plate assays, and subcutaneous (BxPC-3, αvβ6 positive), orthotopic pancreatic (AsPC-1, αvβ6 positive), and spontaneous transgenic PDAC-mouse models. The agent was compared to a scrambled control peptide. NIRF signals were visualized using PEARL imaging system. Results: R01-MG-IRDye800 accumulated selectively in PDAC with highest tumor-to-background ratios of 7.6, which proved suitable for intraoperative detection and delineation of PDAC and small tumor nodules in mice, between 6 and 24 hr postinjection. The agent outperformed the control peptide. Ex vivo fluorescence and pathologic examination confirmed tumor specificity and distribution. Conclusion: Our Results indicate that R01-MG-IRDye800 shows promise to recognize PDAC for fluorescent-guided surgery. This tracer can help improve the stratification of patients for potentially curative, margin-negative resection.

A Novel Near-Infrared Fluorescent Probe TMTP1-PEG4-ICG for in Vivo Tumor Imaging.

Molecular imaging agents are considered to be promising tracers for tumor imaging and guided therapy. TMTP1 was screened through the FliTrx bacterial peptide display system in our laboratory previously and shown to specifically target to primary tumors and metastatic foci. In this study, small peptide TMTP1 was designed to conjugate to a near-infrared fluorescent agent ICG derivative ICG-OSu through PEG4, forming the novel probe TMTP1-PEG4-ICG. It was successfully synthesized and certified. CCK-8 assay showed that it was nontoxic to normal cells and cancerous cells. Dynamics study indicated that the probe was cleared through the liver-intestine and kidney-bladder pathway. Tumor targeting capability of this probe in vitro was evaluated on 4T1, SiHa, HeLa, S12, and HaCaT cells by flow cytometry. In vivo imaging of 4T1 and HeLa tumor-bearing mice further identified the tumor homing ability. As we had expected, the probe showed excellent affinity to cancer cells not only in vitro but also in vivo, whether in murine tumor or humanized tumor. In conclusion, TMTP1-PEG4-ICG demonstrated ideal imaging effects on tumor-bearing mice model, providing new opportunities for tumor diagnostic or guiding resection.

Image-Guided Surgery in Patients with Pancreatic Cancer: First Results of a Clinical Trial Using SGM-101, a Novel Carcinoembryonic Antigen-Targeting, Near-Infrared Fluorescent Agent

BackgroundNear-infrared (NIR) fluorescence is a promising novel imaging technique that can aid in intraoperative demarcation of pancreatic cancer (PDAC) and thus increase radical resection rates. This study investigated SGM-101, a novel, fluorescent-labeled anti-carcinoembryonic antigen (CEA) antibody. The phase 1 study aimed to assess the tolerability and feasibility of intraoperative fluorescence tumor imaging using SGM-101 in patients undergoing a surgical exploration for PDAC.MethodsAt least 48 h before undergoing surgery for PDAC, 12 patients were injected intravenously with 5, 7.5, or 10 mg of SGM-101. Tolerability assessments were performed at regular intervals after dosing. The surgical field was imaged using the Quest NIR imaging system. Concordance between fluorescence and tumor presence on histopathology was studied.ResultsIn this study, SGM-101 specifically accumulated in CEA-expressing primary tumors and peritoneal and liver metastases, allowing real-time intraoperative fluorescence imaging. The mean tumor-to-background ratio (TBR) was 1.6 for primary tumors and 1.7 for metastatic lesions. One false-positive lesion was detected (CEA-expressing intraductal papillary mucinous neoplasm). False-negativity was seen twice as a consequence of overlying blood or tissue that blocked the fluorescent signal.ConclusionThe use of a fluorescent-labeled anti-CEA antibody was safe and feasible for the intraoperative detection of both primary PDAC and metastases. These results warrant further research to determine the impact of this technique on clinical decision making and overall survival.

Determination of the surgical margin in laparoscopic liver resections using infrared indocyanine green fluorescence.

Laparoscopic liver resection is increasingly used to treat patients with hepatic tumor. However, during laparoscopic resection, information obtained by palpation using laparoscopic forceps or from intraoperative ultrasonography is extremely limited, which may pose a risk for positive surgical margins. This study aimed to investigate the feasibility and clinical application of near-infrared (NIR) fluorescence imaging to guide laparoscopic liver resection of a liver tumor and secure the surgical margins. A preliminary study in 25 patients was conducted. NIR imaging was used intraoperatively during laparoscopic liver resection. The liver tumors were preoperatively labeled by intravenously injecting the patients with indocyanine green dye (0.5mg/kg), an NIR fluorescence agent. During the surgical procedure, the PINPOINT Endoscopic Fluorescence Imaging System was used to assess the surgical margin by using real-time endoscopic high-definition visible and NIR fluorescence imaging. All tumors were identified and resected laparoscopically by using the PINPOINT system, and all resections successfully secured the surgical margin. The pathological findings of all tumors indicated negative margins, defined as R0. This technique showed the potential to improve the intraoperative identification and demarcation of tumors. Its use could potentially reduce the number of positive resection margins.

Noninvasive photoacoustic and fluorescent tracking of optical dye labeled T cellular activities of diseased sites at new depth.

The migration of immune cells is crucial to the immune response. Visualization of these processes has previously been limited because of the imaging depth. We developed a deep-penetrating, sensitive and high-resolution method to use fast photoacoustic tomography (PAT) to image the dynamic changes of T cells in lymph node and diseases at new depth (up to 9.5 mm). T cells labeled with NIR-797-isothiocyanate, an excellent near-infrared photoacoustic and fluorescent agent, were intravenously injected to the mice. We used fluorescence imaging to determine the location of T cells roughly and photoacoustic imaging is used to observe T-cell responses in diseased sites deeply and carefully. The dynamic changes of T cells in lymph node, acute disease (bacterial infection) and chronic disease (tumor) were observed noninvasively by photoacoustic and fluorescence imaging at different time points. T cells accumulated gradually and reached a maximum at 4 hours and declined afterwards in lymph node and bacterial infection site. At tumor model, T cells immigrated to the tumor with a maximum at 12 hours. Our study can not only provide a new observing method for immune activities tracking, but also enable continuous monitoring for therapeutic interventions.

Intraoperative Pancreatic Cancer Detection using Tumor-Specific Multimodality Molecular Imaging.

Operative management of pancreatic ductal adenocarcinoma (PDAC) is complicated by several key decisions during the procedure. Identification of metastatic disease at the outset and, when none is found, complete (R0) resection of primary tumor are key to optimizing clinical outcomes. The use of tumor-targeted molecular imaging, based on photoacoustic and fluorescence optical imaging, can provide crucial information to the surgeon. The first-in-human use of multimodality molecular imaging for intraoperative detection of pancreatic cancer is reported using cetuximab-IRDye800, a near-infrared fluorescent agent that binds to epidermal growth factor receptor. A dose-escalation study was performed to assess safety and feasibility of targeting and identifying PDAC in a tumor-specific manner using cetuximab-IRDye800 in patients undergoing surgical resection for pancreatic cancer. Patients received a loading dose of 100mg of unlabeled cetuximab before infusion of cetuximab-IRDye800 (50mg or 100mg). Multi-instrument fluorescence imaging was performed throughout the surgery in addition to fluorescence and photoacoustic imaging ex vivo. Seven patients with resectable pancreatic masses suspected to be PDAC were enrolled in this study. Fluorescence imaging successfully identified tumor with a significantly higher mean fluorescence intensity in the tumor (0.09 ± 0.06) versus surrounding normal pancreatic tissue (0.02 ± 0.01), and pancreatitis (0.04 ± 0.01; p < 0.001), with a sensitivity of 96.1% and specificity of 67.0%. The mean photoacoustic signal in the tumor site was 3.7-fold higher than surrounding tissue. The safety and feasibilty of intraoperative, tumor-specific detection of PDAC using cetuximab-IRDye800 with multimodal molecular imaging of the primary tumor and metastases was demonstrated.

Development and Preclinical Validation of a Cysteine Knottin Peptide Targeting Integrin αvβ6 for Near-infrared Fluorescent-guided Surgery in Pancreatic Cancer.

Purpose: Intraoperative near-infrared fluorescence (NIRF) imaging could help stratification for the proper primary treatment for patients with pancreatic ductal adenocarcinoma (PDAC), and achieve complete resection, as it allows visualization of cancer in real time. Integrin αvβ6, a target specific for PDAC, is present in >90% of patients, and is able to differentiate between pancreatitis and PDAC. A clinically translatable αvβ6-targeting NIRF agent was developed, based on a previously developed cysteine knottin peptide for PET imaging, R01-MG, and validated in preclinical mouse models.Experimental Design: The applicability of the agent was tested for cell and tissue binding characteristics using cell-based plate assays, subcutaneous, and orthotopic pancreatic models, and a transgenic mouse model of PDAC development (Pdx1-Cretg/+;KRasLSL G12D/+;Ink4a/Arf-/-). IRDye800CW was conjugated to R01-MG in a 1:1 ratio. R01-MG-IRDye800, was compared with a control peptide and IRDye800 alone.Results: In subcutaneous tumor models, a significantly higher tumor-to-background ratio (TBR) was seen in BxPC-3 tumors (2.5 ± 0.1) compared with MiaPaCa-2 (1.2 ± 0.1; P < 0.001), and to the control peptide (1.6 ± 0.4; P < 0.005). In an orthotopic tumor model, tumor-specific uptake of R01-MG-IRDye800 was shown compared with IRDye800 alone (TBR 2.7 vs. 0.86). The fluorescent signal in tumors of transgenic mice was significantly higher, TBR of 3.6 ± 0.94, compared with the normal pancreas of wild-type controls, TBR of 1.0 ± 0.17 (P < 0.001).Conclusions: R01-MG-IRDye800 shows specific targeting to αvβ6, and holds promise as a diagnostic and therapeutic tool to recognize PDAC for fluorescence-guided surgery. This agent can help improve the stratification of patients for a potentially curative, margin-negative resection. Clin Cancer Res; 24(7); 1667-76. ©2018 AACR.

Mitochondria-targeted fluorescent carbon nano-platform for NIR-triggered hyperthermia and mitochondrial inhibition

Abstract We report mitochondria-targeted photothermal nanoparticles with the blocker 3-bromopyruvate (BP), delocalized lipophilic triphenylphosphonium (TPP) cations to target them to the mitochondrial membrane, and folic acid (FA) to target cancer cells. The carbonized polyethylene glycol grafted poly (dimethyl aminoethyl methacrylate)-q-catechol (F-PEG- g -PDMA-CCDP) was crosslinked with boronic acid-grafted polyethylene glycol-g-poly (dimethyl aminoethyl methacrylate) conjugated with IR825 as a near-infrared (NIR) responsive fluorescent agent, FA, TPP, BP (PEG- g -PDMA-FA/IR/TPP/BP). The F-PEG- g -PDMA-CCDP@PEG- g -PDMA-FA/IR/TPP/BP (F-FNP) showed in vitro anticancer activity to normal and cancer cell under NIR light treatments. The blocking of metabolic activity in mitochondria with a photothermal system might represent a new pathway for cancer therapy.

Near-Infrared Heptamethine Cyanine Based Iron Oxide Nanoparticles for Tumor Targeted Multimodal Imaging and Photothermal Therapy

Near-infrared fluorescent (NIRF) imaging modality holds great promise for tumor detection and offers several advantages of bioimaging, such as high tissue penetration with less background scattering. The disadvantage of NIRF bioimaging is that it has very low spatial resolution. Thus, the combination of NIRF with magnetic resonance imaging (MRI) is a good option because MRI can provide anatomical information with a higher resolution. Heptamethine cyanine dye (MHI-148) has been reported to have tumor-targeting capability which was used here as the NIRF agent. DSPE-SPION nanoparticles were synthesized by the solvent hydration method and conjugated with MHI-148 dye to form a MRI/NIRF dual imaging probe. The size and charge of the MHI-DSPE-SPION were found to be about 84 ± 6 nm and 3.7 mV by DLS & Zeta Potential analysis. In vivo MRI of the SCC7 tumor showed an enhanced accumulation of MHI-DSPE-SPION, peaking at day 1, compared to 4 hrs with the control DSPE-SPION. An in vivo photothermal tumor reduction study was done on the SCC7 tumor of BALB/c nude mice. Tumor reduction study showed complete tumor removal after 8 days. In conclusion, MHI-DSPE-SPION can be used as a cancer theranostics material because it provides MRI-optical imaging capabilities and the photothermal therapy (PTT) effect.

Improving Surgical Resection of Metastatic Liver Tumors With Near-Infrared Optical-Guided Fluorescence Imaging.

Objective The aim of this study was to investigate the feasibility and future clinical applications of near-infrared (NIR) fluorescence imaging to guide liver resection surgery for metastatic cancer to improve resection margins. Summary Background Data A subset of patients with metastatic hepatic tumors can be cured by surgery. The degree of long-term and disease-free survival is related to the quality of surgery, with the best resection defined as "R0" (complete removal of all tumor cells, as evidenced by microscopic examination of the margins). Although intraoperative ultrasonography can evaluate the surgical margins, surgeons need a new tool to perfect the surgical outcome. Methods A preliminary study was performed on 3 patients. We used NIR imaging postoperatively "ex vivo" on the resected liver tissue. The liver tumors were preoperatively labelled by intravenously injecting the patient with indocyanine green (ICG), a NIR fluorescent agent (24 hours before surgery, 0.25 mg/kg). Fluorescent images were obtained using a miniaturized fluorescence imaging system (FluoStic, Fluoptics, Grenoble, France). Results After liver resection, the surgical specimens from each patient were sliced into 10-mm sections in the operating room and analyzed with the FluoStic. All metastatic tumors presented rim-type fluorescence. Two specimens had incomplete rim fluorescence. The pathologist confirmed the presence of R1 margins (microscopic residual resection), even though the ultrasonographic analysis indicated that the result was R0. Conclusions Surgical liver resection guided by NIR fluorescence can help detect potentially uncertain anatomical areas that may be missed by preoperative imaging and by ultrasonography during surgery. These preliminary results will need to be confirmed in a larger prospective patient series.

A Novel Tumor-Specific Agent for Intraoperative Near-Infrared Fluorescence Imaging: A Translational Study in Healthy Volunteers and Patients with Ovarian Cancer.

Completeness of cytoreductive surgery is a key prognostic factor for survival in patients with ovarian cancer. The ability to differentiate clearly between malignant and healthy tissue is essential for achieving complete cytoreduction. Using current approaches, this differentiation is often difficult and can lead to incomplete tumor removal. Near-infrared fluorescence imaging has the potential to improve the detection of malignant tissue during surgery, significantly improving outcome. Here, we report the use of OTL38, a near-infrared (796 nm) fluorescent agent, that binds folate receptor alpha, which is expressed in >90% of epithelial ovarian cancers. We first performed a randomized, placebo-controlled study in 30 healthy volunteers. Four single increasing doses of OTL38 were delivered intravenously. At fixed times following drug delivery, tolerability and blood/skin pharmacokinetics were assessed. Next, using the results of the first study, three doses were selected and administered to 12 patients who had epithelial ovarian cancer and were scheduled for cytoreductive surgery. We measured tolerability and blood pharmacokinetics, as well as the ability to detect the tumor using intraoperative fluorescence imaging. Intravenous infusion of OTL38 in 30 healthy volunteers yielded an optimal dosage range and time window for intraoperative imaging. In 12 patients with ovarian cancer, OTL38 accumulated in folate receptor alpha-positive tumors and metastases, enabling the surgeon to resect an additional 29% of malignant lesions that were not identified previously using inspection and/or palpation. This study demonstrates that performing real-time intraoperative near-infrared fluorescence imaging using a tumor-specific agent is feasible and potentially clinically beneficial. Clin Cancer Res; 22(12); 2929-38. ©2016 AACR.

Abstract 656: In Vivo Plaque Inflammation and Endothelial Permeability Independently Predict Atherosclerosis Progression: A Serial Multimodality Imaging Study

Background: Atheroma inflammation impairs plaque stability and promotes plaque progression and complications. However, it is unknown how measures of plaque biology relate to changes in plaque burden, and whether plaque biology can independently predict plaque progression in coronary-sized arteries. This study evaluated the ability of intravascular near-infrared fluorescence (NIRF) biological imaging to inform experimental atheroma progression in vivo. Methods: Atherosclerosis was induced by balloon-injury in the aorta of 14 cholesterol-fed rabbits. Serial intravascular ultrasound (IVUS) and dual-modality intravascular NIRF - optical coherence tomography (OCT) imaging was performed following injection of a NIRF molecular imaging agent of plaque inflammatory protease activity (ProSense VM110; n=7), or impaired plaque endothelial permeability (indocyanine green (ICG); n=7). Plaque progression was further assessed by IVUS change in plaque burden. Regression analysis was used to evaluate the association of NIRF with plaque progression. In vivo imaging results were corroborated by ex vivo fluorescence reflectance imaging, fluorescence microscopy, and histopathology. Results: Quantitative analysis of 1,811 axial images spanning individual plaques, the change in NIRF plaque biological signals from 8 to 12 weeks strongly correlated with IVUS plaque burden from 8 to 12 weeks (ProSense VM110: r=0.774; ICG: r=0.572; p&lt;0.0001). This finding remained significant on multivariate analysis adjusted for IVUS plaque burden, lumen area, and remodeling index (p&lt;0.001). In additional multivariate analyses, the baseline NIRF signal at 8 weeks further predicted the magnitude of plaque progression even after adjustment for baseline plaque burden (p&lt;0.001 for Prosense VM110; p=0.004 for ICG). Histology demonstrated NIRF agent uptake in inflamed, lipid-rich plaques. Conclusion: Plaque pathobiology and plaque burden progress in concert as assessed by translatable intravascular NIRF imaging technology. The baseline NIRF inflammation and impaired plaque permeability signals independently predict plaque progression. Integrated biological-microstructural imaging may enhance the ability to detect high-risk plaques at risk of progression.

Abstract 591: Development of Near-infrared Fluorescent Probe for Targeted Uptake by Atherosclerotic Plaque Macrophages

Macrophages are a pivotal element in the development of atherosclerotic plaques and their polarization strongly affects plaque stability. Development of molecular imaging techniques to identify vulnerable plaques in atherosclerotic vessel walls will be a valuable diagnostic tool to assess patients` risk of myocardial infarction or stroke and to adjust therapy. Imaging of unstable plaques has so far been performed by using PET imaging agent [ 18 F] FDG. Fluorescence imaging using near-infrared fluorescent agents offers several advantages, as they are simple to use and minimally invasive. We have developed an activable near-infrared fluorescent probe using either peptide-linked ICG dye (indocyanine green) or free ICG as cargo in liposomes. The liposomes were labeled with phosphatidyl serine in order to trigger phagocytic uptake by macrophages. We have investigated the properties of our liposome probes in order to assess their suitability for screening of atherosclerosis risk patients in a wide array of different experimental models including cell culture and various animals (apoE -/- mice, WHHL rabbits and macaca fascicularis monkeys). Cell culture experiments using the human monocytic cell line THP-1 after differentiation into macrophages using the phorbol ester PMA and polarization of the macrophages by either LPS/IFNγ for M1 polarization or IL-4/ IL-13 for M2 polarization have shown considerable differences in uptake efficiency for the liposomes. M2 macrophages were found to show highest phagocytic activity while not polarized M0 were intermediate and M1 macrophages were least active. Polarization was confirmed by measuring known marker genes (TNFA, CCL3, MRC1) of macrophage polarization by RT-qPCR. In the animal studies we observed enrichment of ICG-labeled liposomes in atherosclerotic plaques of apoE -/- mice as well as WHHL rabbits. Macaca fascicularis experiments attempted to simulate final application in human subjects by detecting atherosclerotic plaques within the carotid aorta. Preliminary results indicate promising potential for liposome probes.

Delta-Opioid Receptor (δOR) Targeted Near-Infrared Fluorescent Agent for Imaging of Lung Cancer: Synthesis and Evaluation In Vitro and In Vivo.

In the United States, lung cancer is the leading cause of cancer death and ranks second in the number of new cases annually among all types of cancers. Better methods or tools for diagnosing and treating this disease are needed to improve patient outcomes. The delta-opioid receptor (δOR) is reported to be overexpressed in lung cancers and not expressed in normal lung. Thus, we decided to develop a lung cancer-specific imaging agent targeting this receptor. We have previously developed a δOR-targeted fluorescent imaging agent based on a synthetic peptide antagonist (Dmt-Tic) conjugated to a Cy5 fluorescent dye. In this work, we describe the synthesis of Dmt-Tic conjugated to a longer wavelength near-infrared fluorescent (NIRF) dye, Li-cor IR800CW. Binding affinity of Dmt-Tic-IR800 for the δOR was studied using lanthanide time-resolved fluorescence (LTRF) competitive binding assays in cells engineered to overexpress the δOR. In addition, we identified lung cancer cell lines with high and low endogenous expression of the δOR. We confirmed protein expression in these cell lines using confocal fluorescence microscopy imaging and used this technique to estimate the cell-surface receptor number in the endogenously expressing lung cancer cell lines. The selectivity of Dmt-Tic-IR800 for imaging of the δOR in vivo was shown using both engineered cell lines and endogenously expressing lung cancer cells in subcutaneous xenograft models in mice. In conclusion, the δOR-specific fluorescent probe developed in this study displays excellent potential for imaging of lung cancer.

Gold nanorods/mesoporous silica-based nanocomposite as theranostic agents for targeting near-infrared imaging and photothermal therapy induced with laser.

Photothermal therapy (PTT) is widely regarded as a promising technology for cancer treatment. Gold nanorods (GNRs), as excellent PTT agent candidates, have shown high-performance photothermal conversion ability under laser irradiation, yet two major obstacles to their clinical application are the lack of selective accumulation in the target site following systemic administration and the greatly reduced photothermal conversion efficiency caused by self-aggregating in aqueous environment. Herein, we demonstrate that tLyp-1 peptide-functionalized, indocyanine green (ICG)-containing mesoporous silica-coated GNRs (I-TMSG) possessed dual-function as tumor cells-targeting near-infrared (NIR) fluorescent probe and PTT agents. The construction of the nanostructure began with synthesis of GNRs by seed-mediated growth method, followed by the coating of mesoporous silica, the chemical conjugation of PEG and tLyp-1 peptide, and the enclosure of ICG as an NIR imaging agent in the mesoporous. The as-prepared nanoparticles could shield the GNRs against their self-aggregation, improve the stability of ICG, and exhibit negligible dark cytotoxicity. More importantly, such a theranostic nanocomposite could realize the combination of GNRs-based photothermal ablation under NIR illumination, ICG-mediated fluorescent imaging, and tLyp-1-enabled more easy endocytosis into breast cancer cells. All in all, I-TMSG nanoparticles, in our opinion, possessed the strong potential to realize the effective diagnosis and PTT treatment of human mammary cancer.