Indocyanine Green Accumulation Research Articles

Transcutaneous sentinel lymph node detection in skin melanoma with near-infrared fluorescence imaging using indocyanine green.

The aim of the study is to assess whether indocyanine green (ICG) fluorescence can replace technetium in the preoperative detection of sentinel lymph nodes (SLN) from cutaneous melanoma. The current golden standard for SLN detection is the radioisotope technetium. A promising alternative is fluorescence imaging (FLI) using ICG. In this study, we enrolled patients undergoing sentinel lymph node biopsy (SLNB) for skin melanoma at the Erasmus Medical Center between November 2022 and July 2023. The SLNB procedure was performed as a standard of care. After general anesthesia, ICG was injected intradermally around the primary tumor site. Both the patient and the surgeon were not blinded for the location of the SLN. FLI was performed before incision, in vivo after incision, and ex vivo. Fluorescent SLNs were confirmed using the gamma probe in all cases. Thirty-two patients were included in this study, and a total of 39 SLNs were harvested. The transcutaneous detection rate of ICG was 21.9%. The combined ex vivo ICG fluorescence and technetium uptake was 94.9%. One SLN contained only ICG (2.6%) and one SLN contained only technetium-uptake (2.6%). FLI using ICG resulted in a relatively low transcutaneous detection, which means that exclusive use of this technique in its present form is not feasible. However, we did find a high accumulation of ICG in the SLN, indicating the potential of ICG in combination with other imaging techniques.

An indocyanine green-based liquid biopsy test for circulating tumor cells for pediatric liver cancer.

Hepatoblastoma and HCC are the most common malignant hepatocellular tumors seen in children. The aim of this study was to develop a liquid biopsy test for circulating tumor cells (CTCs) for these tumors that would be less invasive and provide real-time information about tumor response to therapy. For this test, we utilized indocyanine green (ICG), a far-red fluorescent dye used clinically to identify malignant liver cells during surgery. We assessed ICG accumulation in cell lines using fluorescence microscopy and flow cytometry. For our CTC test, we developed a panel of liver tumor-specific markers, including ICG, Glypican-3, and DAPI, and tested it with cell lines and noncancer control blood samples. We then used this panel to analyze whole-blood samples for CTC burden with a cohort of 15 patients with hepatoblastoma and HCC and correlated with patient characteristics and outcomes. We showed that ICG accumulation is specific to liver cancer cells, compared to nonmalignant liver cells, non-liver solid tumor cells, and other nonmalignant cells, and can be used to identify liver tumor cells in a mixed population of cells. Experiments with the ICG/Glypican-3/DAPI panel showed that it specifically tagged malignant liver cells. Using patient samples, we found that CTC burden from sequential blood samples from the same patients mirrored the patients' responses to therapy. Our novel ICG-based liquid biopsy test for CTCs can be used to specifically detect and quantify CTCs in the blood of pediatric patients with liver cancer.

Enhancing Tumor Immunotherapy by Multivalent Anti-PD-L1 Nanobody Assembled via Ferritin Nanocage.

Increasing immunotherapy response rate and durability can lead to significant improvements in cancer care. To address this challenge, a novel multivalent immune checkpoint therapeutic platform is constructed through site-specific ligation of anti-PD-L1 nanobody (Nb) on ferritin (Ftn) nanocage. Nb-Ftn blocks PD-1/PD-L1 interaction and downregulates PD-L1 levels via endocytosis-induced degradation. In addition, the cage structure of Ftn allows encapsulation of indocyanine green (ICG), an FDA-approved dye. Photothermal treatment with Nb-Ftn@ICG induces immunogenic death of tumor cells, which improves systemic immune response via maturation of dendritic cells and enhanced infiltration of T cells. Moreover, Nb-Ftn encapsulation significantly enhances cellular uptake, tumor accumulation and retention of ICG. In vivo assays showed that this nanoplatform ablates the primary tumor, suppresses abscopal tumors and inhibits tumor metastasis, leading to a prolonged survival rate. This work presents a novel strategy for improving cancer immunotherapy using multivalent nanobody-ferritin conjugates as immunological targeting and enhancing carriers.

Own experience of indocyanine green use in the diagnosis and treatment of breast cancer in N.N. Petrov NMRC of Oncology

To evaluate the possibility of using the method of sentinel lymph nodes (SLN) detection with indocyanine green (ICG) in patients with early breast cancer and its informativeness. A «Determination of sentinel lymph nodes by fluorescence method intraoperatively with the use of indocyanine green» study, in which 168 patients are currently included, is being conducted in the clinic of the N.N. Petrov NMRC of Oncology from 2017 through the present. All patients who underwent biopsy of sentinel lymph nodes (BSLN) were primary with a T1-2N0M0 stage of process. The average number of axillary lymph nodes removed in BSLN was 3 (1-5). Accumulation of ICG was found in 147 (88%) patients, accumulation of labeled radiocolloid - in 137 (82%), in combination of ICG/radiocolloid - in 167 (99%) based on the results of imaging. The obtained results prove that the informativeness and relative simplicity of this method use allow its application in any hospital where breast cancer is surgically treated, as well as in the absence of radioisotopic equipment.

First experience of applying domestic video fluorescent equipment for visualization and blood flow evaluation of the parathyroid glands

In recent years, predictive methods for assessing the preservation of the parathyroid glands have been actively implemented. The article describes the first experience of evaluating the blood supply of the parathyroid glands by quantitative determination of the indocyanine green (ICG) accumulation index in real time in 6 patients before and after a thyroidectomy with central neck lymph node dissection for papillary thyroid cancer. Intraoperative fluorescent angiography was performed by using domestic equipment with a fluorescent module, as well as by using a domestic medication of ICG. Intraoperative values of the ICG accumulation index were compared with the levels of ionized calcium and parathyroid hormone perioperatively. No clinical manifestations of hypocalcemia were detected in the postoperative period. The obtained results showed the informativeness of the numerical assessment of the intensity of ICG fluorescence. The evaluation of the distribution (accumulation) of ICG has prospects for practical application in thyroid surgery in the formation of tactics for preserving the parathyroid glands and predicting postoperative hypoparathyreosis.

Cell Membrane Coated pH-Responsive Intelligent Bionic Delivery Nanoplatform for Active Targeting in Photothermal Therapy.

To produce pH-responsive bionic high photothermal conversion nanoparticles actively targeting tumors for sensitizing photothermal therapy (PTT). The bionic nanoparticles (ICG-PEI@HM NPs) were prepared by electrostatic adsorption of indocyanine green (ICG) coupled to polyethyleneimine (PEI) and modified with tumor cell membranes. In vitro and in vivo experiments were conducted to investigate the efficacy of ICG-PEI@HM-mediated PTT. The intelligent responsiveness of ICG-PEI@HM to pH promoted the accumulation of ICG and enhanced the PTT performance of ICG-PEI@HM NPs. Compared with free ICG, NPs exhibited great photothermal stability, cellular uptake, and active tumor targeting for PTT. ICG-PEI@HM NPs can enhance the efficacy of PTT and can be used as a new strategy for the construction of photothermal agents.

Radioactive nanosized colloids and indocyanine green identify the same sentinel lymph nodes in oral squamous cell carcinoma

PurposeNear-infrared fluorescence imaging using indocyanine green (ICG) combined with radioactive markers has the potential to improve sentinel lymph-node (SLN) mapping in oral squamous cell carcinoma (OSCC). This study aimed to evaluate the ability of 99mTc and ICG in identifying the sentinel lymph nodes in patients with early stage OSCC.MethodsData were collected prospectively, and a retrospective analysis of 15 patients with early stage OSCC and a cN0 neck was performed. All patients received peritumoral injection of 99mTc the day before surgery and ICG was administered intraoperatively. Intentionally, the application of the two different tracers were done by two different physicians with varying degrees of experience. The number of identified lymph nodes positive for 99mTc and ICG, the overlap or possible discrepancies of both methods, and the time until fluorescence signals of ICG were detected were noted.ResultsIn all patients, a 100% agreement in sentinel lymph-node identification was achieved, regardless of both the exact location of the peritumoral injection and the experience of the injecting surgeon. Time until ICG accumulation in the sentinel lymph node was consistently found to be between 1 and 3 min.ConclusionICG constitutes a viable and useful addition to 99mTc for intraoperative sentinel lymph-node detection in this study.

Vascular permeability in HPV+ oropharyngeal cancers aids in fluorescent image-guided transoral robotic surgery using indocyanine green.

Indocyanine green (ICG) fluorescent image (FI)-guided surgery has demonstrated success in improving intraoperative visualization and tumor resections. The objectives were to evaluate the use of IGC in FI-guided transoral robotic surgery (TORS) and the underlying molecular mechanism. HPV+ oropharyngeal squamous cell carcinoma (OPSCCa) patient (n = 10) undergoing TORS were enrolled in this prospective study. Participants received intravenous ICG. Excised tissues were evaluated for ICG accumulation, tumor demarcation, and pathological characteristics using In-vivo imaging system (IVIS), histology, and RNA sequencing. ICG accumulation was significantly increased in primary tumor and pathological lymph nodes compared with normal tissues (p < 0.001). IVIS was 91.3% accurate in identifying OPSCCa in excised tissues; the correlation between IVIS- and histologically determined tumor tissues was significant (R2 = 0.8301; p = 0.001). Genes associated with vascular and angiogenic signaling pathways were significantly upregulated in OPSCCa tissues. ICG effectively demarcates tumor margins in OPSCCa, due to the increased upregulation of genes associated with vascular permeability.

Abstract A008: An indocyanine green-based liquid biopsy test for circulating tumor cells for hepatoblastoma

Abstract Introduction: Hepatoblastoma (HB) is the most common pediatric primary liver tumor and has the fastest rising incidence of all pediatric solid tumors. Tumor progression is monitored with MRI, chest CT, and serum levels of Alpha fetoprotein. Unfortunately, these assays involve exposing children to radiation and anesthesia and are not always accurate. The goal of this work is to develop and validate a liquid biopsy test for circulating tumor cells (CTCs) with a panel of HB-specific markers to provide a less invasive and more accurate way of assessing disease. Methods: We first explored accumulation of the far-red fluorescent dye indocyanine green (ICG) in widely available cell lines (HepG2, Huh-6, Hep3B, HepRG, 293T, SH-SY5Y, A549), our own HB patient-derived cell line (HB17), and primary fibroblasts. We assessed ICG accumulation with fluorescence microscopy and flow cytometry, including standard flow cytometry on a BD Symphony instrument and imaging flow cytometry on the Amnis ImageStream X MK II instrument. Based on this data, we then developed a new method for quantifying CTC burden from patient whole blood samples using HB-specific markers ICG, Glypican-3 (GPC3), and DAPI with fluorescence microscopy and flow cytometry readouts. We tested this panel with cell lines and non-cancer control blood samples, as well as blood samples from mice harboring intrahepatic patient-derived xenograft (PDX) tumors representing HB. Finally, we used this panel to analyze whole blood samples for CTC burden with a cohort of HB patients and correlated with patient characteristics and outcomes. Results: First, we showed that ICG accumulation is specific to liver cancer cells (HepG2, Huh-6, Hep3B, HB17), compared to non-malignant liver cells (HepRG), non-liver solid tumor cells (SH-SY5Y, A549), and non-malignant cells (293T, primary fibroblasts). In addition, we found that ICG+ liver tumor cells remain positive for at least 96 hours after uptake. We also showed that ICG accumulation can be used to identify HepG2 HB cells in a mixed population of cells down to a dilution of 1:100 (2.7% ICG+ in the HepG2/SH-SY5Y mix versus 1.9% ICG+ in the SH-SY5Y control). Flow cytometry with HepG2 and A549 cell lines with the ICG/GPC3/DAPI panel showed 94.4% of HepG2 cells were triple ICG+/GPC3+/DAPI+ while 0% of A549 cells were triple ICG+/GPC3+/DAPI+. With non-cancer control blood samples, we identified less than 1 ICG+ cell per ml of blood. We showed the presence of triple ICG+/GPC3+/DAPI+ cells in the blood of animals harboring PDX tumors. Most importantly, with a low-risk HB patient sample, we found 2.25 triple ICG+/GPC3+/DAPI+ cells per ml of blood; with a high-risk sample we counted 17.25 triple ICG+/GPC3+/DAPI+ cells per ml of blood. Conclusions: This work shows the translation from the use of ICG to identify HB lesions in patients during surgery to its role in a novel liquid biopsy test for CTCs, which has the real potential to improve the standard of care by offering a more accurate and less invasive means of monitoring disease. Citation Format: Andres F. Espinoza, Roma H. Patel, Bryan W. Armbruster, Pavan Kureti, Saiabhiroop R. Govindu, Sanjeev A. Vasudevan, Sarah E. Woodfield. An indocyanine green-based liquid biopsy test for circulating tumor cells for hepatoblastoma [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A008.

Continuous organ perfusion monitoring using indocyanine green in a piglet model.

Unrecognized organ hypoperfusion may cause major postoperative complications with detrimental effects for the patient. The use of Indocyanine Green (ICG) to detect organ hypoperfusion is emerging but the optimal methodology is still uncertain. The purpose of this study was to determine the feasibility of real-time continuous quantitative perfusion assessment with Indocyanine Green (ICG) to monitor organ perfusion during minimally invasive surgery using a novel ICG dosing regimen and quantification software. In this experimental porcine study, twelve subjects were administered a priming dose of ICG, followed by a regimen of high-frequency (1 dose per minute), low-dose bolus injections with weight-adjusted (0.008mg/kg) ICG allowing for continuous perfusion monitoring. In each pig, one randomly assigned organ of interest [stomach (n = 3), ascending colon (n = 3), rectum (n = 3) and spleen (n = 3)] was investigated with varying camera conditions. Video recording was performed with the 1588 AIM Stryker camera platform and subsequent quantitative analysis of the ICG signal were performed using a research version of a commercially available surgical real-time analysis software. Using a high-frequency, low-dose bolus ICG regimen, fluorescence visualization and quantification in abdominal organs were successful in the stomach (3/3), ascending colon (1/3), rectum (2/3), and the spleen (3/3). ICG accumulation in the tissue over time did not affect the quantification process. Considerable variation in fluorescence signal was observed between organs and between the same organ in different subjects. Of the different camera conditions investigated, the highest signal was achieved when the camera was placed 7.5cm from the target organ. This proof-of-concept study finds that real-time continuous perfusion monitoring in different abdominal organs using ICG is feasible. However, the study also finds a large variation in fluorescence intensity between organs and between the same organ in different subjects while using a fixed weight-adjusted dosing regimen using the same camera setting and placement.

Near-infrared fluorescence imaging during ex vivo lung perfusion: Noninvasive real-time evaluation of regional lung perfusion and edema

ObjectiveEx vivo lung perfusion (EVLP) is an excellent platform to evaluate donor lung function before transplantation, but novel methods are needed to accurately confirm transplant quality. Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) has been used in various clinical perioperative applications to evaluate tissue perfusion. We used NIRF imaging during pig and human EVLP to evaluate donor lung perfusion and edema. MethodsPig lungs with various degrees of lung injury (n = 10) and human lungs rejected from clinical transplantation (n = 3) were imaged during EVLP using intravascular ICG and a SPY Elite (Stryker) NIRF imaging unit. Optimal ICG and imaging conditions, and perfusion and edema quantification methods, were established. Pig lung transplants with extended graft preservation (n = 5) and control native lungs (n = 6) were also imaged. ResultsA single ICG dose resulted in sustained donor lung NIRF throughout the EVLP. Even and homogenous ICG signal was demonstrated in areas of normal lung. Low NIRF was present in regions with poor tissue perfusion, and rapid, intense ICG accumulation occurred in damaged and edematous areas. Segmental perfusion defects were common in the peripheral and elevated regions of the lungs, and serial imaging showed gradual perfusion recovery during EVLP. Impaired microvascular reperfusion, indicated by a decreased NIRF ingress rate, was detected in transplanted pig lungs early after reperfusion. ConclusionsNIRF imaging enables noninvasive real-time evaluation of lung perfusion and edema during EVLP. Prospective clinical studies are needed to determine the role of NIRF imaging in donor lung assessment and selection, and prediction of posttransplant outcomes.

Vascular permeability in chronic rhinosinusitis enhances accumulation and retention of nanoscale pegylated liposomes

Chronic rhinosinusitis (CRS) is a debilitating inflammatory disorder of the sinonasal mucosa that substantially diminishes patient quality of life. Progress surrounding management of this disease has been crippled by a lack of therapeutic innovation. It has been posited that increased vascularity within the diseased sinuses of patients with CRS may allow for improved systemic drug delivery via nanoscale liposomal carriers. Such a system could enhance drug distribution, accumulation, and retention within the sinuses, ultimately leading to improved patient outcomes. PEGylated liposomes loaded with indocyanine green (ICG) were synthesized, characterized and systemically administered in a mouse model of CRS. Accumulation and retention of ICG in sinonasal tissue were evaluated. Compared to healthy controls, CRS mice showed significant sinonasal tissue accumulation and retention of PEGylated liposomal ICG for up to 21 days (P < 0.001). Conversely, free ICG was eliminated from the body after 24 h in both groups.

Usability of Indocyanine Green in Robot-Assisted Hepatic Surgery.

Recent developments in robotic surgery have led to an increasing number of robot-assisted hepatobiliary procedures. However, a limitation of robotic surgery is the missing haptic feedback. The fluorescent dye indocyanine green (ICG) may help in this context, which accumulates in hepatocellular cancers and around hepatic metastasis. ICG accumulation may be visualized by a near-infrared camera integrated into some robotic systems, helping to perform surgery more accurately. We aimed to test the feasibility of preoperative ICG application and its intraoperative use in patients suffering from hepatocellular carcinoma and metastasis of colorectal cancer, but also of other origins. In a single-arm, single-center feasibility study, we tested preoperative ICG application and its intraoperative use in patients undergoing robot-assisted hepatic resections. Twenty patients were included in the final analysis. ICG staining helped in most cases by detecting a clear lesion or additional metastases or when performing an R0 resection. However, it has limitations if applied too late before surgery and in patients suffering from severe liver cirrhosis. ICG staining may serve as a beneficial intraoperative aid in patients undergoing robot-assisted hepatic surgery. Dose and time of application and standardized fluorescence intensity need to be further determined.

Difficult HCC of segment 1 in retrocaval position laparoscopic liver resection using ICG and CEIOUS

Background: Contrast-enhanced intraoperative ultrasonography (CEIOUS) is a well known technique used in liver surgery to improve identification and resection of hepatocellular carcinoma ( HCC ) nodules. In recent years , the use of indocyanine green (ICG ) fluorescence has grown in hepatobiliary surgery 1,2 . The range of applications of ICG is various, from the ability to identify biliary anatomy during cholecystectomy to the visualization of HCC nodules based on the accumulation of ICG in cancerous tissues. The combinations of the two technologies could increase tumor detection and the radicality of resection. In this video we present a case of ICG- and CEIOUS-guided laparoscopic liver resection of HCC located in segment 1. Materials and Methods: We present the case of a 81-year-old patient with a history of hypertension and treated hepatitis C infection with a sustained serological response from 2018 and a previous laparotomic resection for a HCC in segment 8. During his regular hepatological follow-up a 25 mm nodule is segment 1 was detected in a retrocaval position. Considering clinical presentation, good liver function (Child A5 - MELD 8 ) and imaging, the patient was scheduled for laparoscopic liver resection. Results and Conclusions: We performed a ICG and CEIOUS guided LLR of segment 1. Surgical specimen margins were free from disease and the patient was discharged in postoperative day 4. CEIOUS and ICG can be combined to help the surgeon to detect the exact position of a deep nodule, covered by the caval vein, allowing better oncological results. Further studies are needed to assess the real benefits of the synchronous application of those technologies.

Intravital study of lymphatic drainage in lung cancer using indocyanine green

Introduction . The knowledge of lymph efflux and its features seems to be significant for diagnosis and treatment of cancer diseases. The purpose of this paper is exploration of the lymph efflux from lungs by infrared fluorescence in patients with lung cancer. Materials and methods . Indocyanine green (ICG) was injected peritumorally during the lung resection in 92 patients with non-small cells lung cancer (NSCLC). We managed to reliably visualize ICG fluorescence in at least 1 regional lymph node (LN) of the lung root or mediastinum in 70 patients (76%), they are included in the study. Results . The accumulation of ICG was detected in 63% of patients in the LN of the root and mediastinum, in 27% of cases - in the mediastinum only, in 10% of patients - in the hilar nodes only. There was no correlation between lesion of lymph node group and ICG injection in any lung lobe. Conclusions . The lymph efflux from different lung lobe is variable in patients with lung cancer. The lymph can run toward the nodes of both lung root and mediastinum.

Evaluation of Lung Quality by Near-Infrared Fluorescent Imaging during Ex Vivo Lung Perfusion

Improved real-time assessment of donor lung quality during Ex Vivo Lung Perfusion (EVLP) could enhance safe utilization of lungs for transplantation. Near-infrared (NIR) fluorescent imaging with indocyanine green (ICG) has been used in various clinical intraoperative applications to evaluate tissue perfusion. We investigated the feasibility of NIR imaging during EVLP and aimed to detect and quantify lung perfusion and permeability. Pig lungs with extended 24-hour cold ischemia (n=4) and human lungs rejected from clinical transplantation (n=2) were assessed with NIR imaging during EVLP. Serial NIR imaging was performed with SPY Elite imaging system after ICG (0.3, 0.6 or 1.0 mg) administration through pulmonary artery (Fig A). Tissue perfusion was quantified using SPYQ analysis software, and tissue ICG accumulation was correlated with lung damage. Strong NIR signal was detected immediately after ICG administration with 0.6 mg (pig lungs) or 1.0 mg (human lungs) doses resulting in optimal fluorescence for tissue perfusion evaluation. In contrast to the transient kinetics and fast liver metabolism during clinical in vivo ICG administration, a single ICG dose during EVLP resulted in stable NIR signal for over 10 hours. Perfusion quantification of pig lungs with extended cold preservation revealed peripheral areas with compromised tissue perfusion that gradually recovered over time with recruitment of additional pulmonary vascular beds (Fig B). ICG accumulation was detected in sites with damage and increased vascular permeability in pig and human lungs (Fig C and D). NIR imaging with a clinically-approved intravascularly-delivered ICG fluorescent probe can dynamically quantify tissue perfusion and detect damage-induced vascular permeability. This novel and promising imaging modality could be used during EVLP to assess lung quality, or to determine effects of therapeutics that target tissue perfusion and vascular permeability.

Indocyanine Green-Coated Polycaprolactone Micelles for Fluorescence Imaging of Tumors.

Recently, near-infrared (NIR) fluorescent dyes such as indocyanine green (ICG) have received tremendous interest as contrast agents for use in fluorescence-guided, intraoperative cancer resection surgery. However, despite showing great promise, ICG has many shortcomings such as rapid clearance and poor tumor accumulation. To improve the selective accumulation of ICG within tumors, numerous groups have formulated ICG into nanoparticles, but these approaches can suffer from rapid leakage of ICG, use of materials that exhibit poor or incomplete excretion, or complex chemistries that are not easily amenable to scale up for clinical use. Here, we developed a simple one-step method to prepare ICG-based fluorescent micelles that are composed solely of unmodified ICG and polycaprolactone (PCL), two clinically used materials with well-characterized safety profiles. The ICG-PCL micelles are prepared via oil-in-water emulsions, and the resulting micelles exhibit a uniform size, good reproducibility, and high loading efficiency. In vivo fluorescence imaging demonstrated that the ICG-PCL micelles led to a significant improvement in the accumulation and retention of ICG, in four different tumor models, compared with free dye, making them an attractive option for image-guided surgery.

Real-time surgical margin assessment using ICG-fluorescence during minimally invasive resections of colorectal liver metastases

Background: Achieving a radical resection with >1 mm margin is associated with improved overall survival in patients with colorectal liver metastases (CRLM). Nonetheless, almost a third of surgeries end up being margin-positive in both open and minimally invasive procedures. Near-infrared fluorescent (NIRF) guidance using indocyanine green (ICG) as a contrast agent has been studied to identify additional metastases during surgery. NIRF imaging shows a characteristic fluorescent ‘rim’ surrounding the CRLM, caused by accumulation of ICG in the surrounding hepatocytes(fig. 1a, b). We hypothesize that by using NIRF image-guidance to remove a metastasis with the entire surrounding fluorescent rim, the surgeon can effectively acquire margin negative resections (fig. 1c). Methods: A balanced cohort was composed from the institute’s database by selecting 15 lesions (out of 13 patients), which were resected by minimally-invasive approach using ICG. Target lesions were identified in vivo using the fluorescent rim. NIRF images were acquired during surgery from both the resection specimen and the wound bed to identify potential positive margins. NIRF images were correlated on a later stage to the histopathological findings. Results: Seven robot-assisted and six laparoscopic procedures were included. A total of 8 lesions were reported as a positive margin after histopathological examination. The median lesion size was 21 mm (range: 8 - 37) All lesions which were NIRF negative in vivo were reported as negative margins (fig. 1d). Lesions which showcased a protruding rim in vivo were diagnosed as a positive margin in 87.5% of cases (fig 1e). Three of these lesions also showed residual rim in the wound bed (fig. 1f). Conclusion: Image-guided surgery using real-time ICG-fluorescence has the potential to aid surgeons in achieving a negative margin in minimal invasive liver metastasectomies. A nationwide prospective study, the MIMIC-Trial, is already open for inclusion to further study this technique.

Passive Distribution of Indocyanine-Green via the Enhanced Permeability and Retention Effect Demonstrates Similar Tumor Sensitivity and Specificity Compared to Tumor-Targeting 5-Aminolevulinic Acid in Rodent Allograft and Human Brain Tumors

Abstract INTRODUCTION Fluorescence-guided-surgery can potentially facilitate maximal safe resection of high-grade-gliomas. 5-aminolevulinic-acid (5-ALA) leads to enzymatic accumulation of protoporphyrin-IX (PpIX) in high-grade neoplastic cells. A high-dose infusion of indocyanine-green (ICG) (Second-Window-ICG or SWIG) relies primarily on the passive accumulation of ICG in neoplastic tissue via enhanced-permeability-and-retention. In this study, we compare 5-ALA and SWIG in a murine allograft HGG model and human patients with HGG. METHODS Six-week-old C57/BL6 mice underwent intracranial implantation of GL261 cells and received 5 mg/kg ICG (24-h pre-euthanasia) and 200 mg/kg 5-ALA (3-h pre-euthanasia) once tumors developed. Fresh brain coronal sections were imaged for PpIX and ICG fluorescence and H&amp;E stains were performed on fixed specimens. The fluorescence images and H&amp;E images were overlaid and multiple region-of-interest (ROIs) were sampled at random to calculate the receiver operating-characteristic for each fluorophore. Furthermore, 3 patients with HGG were administered 5 mg/kg ICG 24-h preoperatively and 20 mg/kg 5-ALA 3-h preoperatively. Intraoperatively, tumor specimens were imaged for both ICG and PpIX fluorescence. RESULTS Four-hundred ROIs were sampled from 25 coronal slices (217 neoplastic). PpIX fluorescence signal-to-background (SBR) was significantly higher in neoplastic ROIs (2.21 vs 1.33, P-value &lt; .0001). 5-ALA accuracy was 79.1% (95% confidence interval 74.5-83.6%). SWIG SBR was significantly higher for neoplastic ROIs (4.25 vs 1.91, P-value &lt; .0001). SWIG accuracy was higher than 5-ALA’s at 88.2% (95% confidence interval 84.7-91.7%) (P-value &lt; .0001). The optimal SBR cutoffs for 5-ALA and SWIG were 1.5 and 2.15, respectively. The most distinct difference between 5-ALA and SWIG distribution was seen in areas of necrosis/hemorrhage, which often showed weak/no PpIX fluorescence but strong SWIG fluorescence. 5-ALA accuracy was lower in necrotic tumors than in non-necrotic tumors (67.8% vs 86.3%, P-value = .0001). In 3 HGG patients who received both 5-ALA and SWIG, 17 biopsy specimens were obtained (15 neoplastic). Near-infrared imaging revealed 14 true-positive, 2 true-negative, and 1 false-negative signals, while PpIX imaging revealed 12 true-positives, 1 true-negative, 1 false-positive, and 3 false-negative signals. CONCLUSION In this first comparative study of 5-ALA and SWIG, we demonstrate similar diagnostic utility of a passive permeability dye (ICG) to an enzymatic functional dye (5-ALA) in HGG. Considering the benefits of near-infrared fluorophores over visible-spectrum fluorophores, further comparative studies in clinical settings are warranted.

Reactive oxygen species and near-infrared light dual-responsive indocyanine green-loaded nanohybrids for overcoming tumour multidrug resistance

The nucleus is in charge of the metabolism and heredity of the cell, and genetic mutations are closely related with tumour multidrug resistance (MDR). Indocyanine green (ICG), the FDA-approved photosensitizer, is widely used for tumour photodynamic therapy (PDT) and photothermal therapy (PTT). Few studies have clarified the cellular distribution of ICG in MDR tumour cells. In the study, ICG distribution was detected in the whole tumour cells of MCF-7 and MCF-7/ADR, especially in the nucleus, which led us to question whether increasing cellular accumulation and nuclear distribution of ICG could be a potential method to overcome MDR. Therefore, a reactive oxygen species (ROS) and near-infrared (NIR) light dual-responsive nanohybrid was constructed with diselenide cross-linked polyamidoamine-Poloxamer 188 and graphene oxide with ICG as payloads (ICG/GPP). The nanohybrid enhanced the stability of ICG and showed an ROS-sensitive release behaviour. More ICG was delivered by ICG/GPP to the MCF-7/ADR cells. After escaping from the lysosome, nuclear accumulation of ICG was increased. Under NIR laser irradiation, ICG/GPP showed increased cytotoxicity for the combined PTT and PDT in MCF-7/ADR cells. Moreover, the expression of P-glycoprotein (P-gp) was suppressed to overcome tumour MDR. The ROS- and NIR- responsive GPP shows potential for the nuclear delivery of drugs to combat tumour MDR.