Photodynamic therapy for human hepatoma-cell-line tumors utilizing biliary excretion properties of indocyanine green

A multiple functional supramolecular system for synergetic treatments of hepatocellular carcinoma

In the current times, achieving specific targeted and controllable drug delivery remains one of the major challenges in the treatment of hepatocellular carcinoma (HCC). The present study reported the development of a multiple functional indocyanine green (ICG)-cyclodextrin (CD) system, wherein loaded etoposide (EPS) was used as the model chemotherapeutic drug. In the developed system, ICG segment served as a photosensitizer for photothermal therapy (PTT) and the targeting moiety, which was primarily attributed to the specific retention properties in HCC tissues. The Ex vivo evaluation showed that ICG-CD@EPS exhibited a laser-triggered release profile with the photothermal efficiency and cytotoxicity towards HepG2 cells. In vivo evaluation suggested that ICG could navigate the systems to HCC tissues and retained at the site for 48 h, producing a drug accumulation in HCC. Further, laser irradiation boosted EPS release and local hyperthermia effects in HCC. Thus, the present study explored a novel and specific HCC targeting mechanism, and provided a feasible and controllable strategy for synergistic PTT and chemotherapy treatments for HCC.

Astragaloside IV suppresses migration and invasion of TGF-β1-induced human hepatoma HuH-7 cells by regulating Nrf2/HO-1 and TGF-β1/Smad3 pathways

Astragaloside IV (AS-IV), one of the major compounds extract from Astragalus membranaceus, has shown attractive anti-cancer effects in certain malignancies. Oxidative stress (OS) is considered as a crucial factor in promoting the progression of hepatocellular carcinoma (HCC). In response to OS, nuclear factor erythroid 2-related factor 2 (Nrf2) upregulates and induces heme oxygenase 1 (HO-1) to combat oxidative damages. The phosphorylation of the COOH-terminal of Smad3 (pSmad3C) activates p21 to resist HCC progression, while the phosphorylation of the linker region of Smad3 (pSmad3L) up-regulates c-Myc transcription to exert promoting effect towards HCC. This study aimed to explore whether AS-IV suppresses migration and invasion of human hepatoma HuH-7 cells by regulating Nrf2/HO-1 and TGF-β₁/Smad3 pathways. HuH-7 cells were induced with TGF-β₁ (9 or 40 pM) to establish HCC model in vitro and pretreated with AS-IV at different concentration (5, 10, and 20 μM) for 24 h. Cell proliferation, migration, invasion, and intracellular reactive oxygen species (ROS) of HuH-7 cells were measured. The expression of Nrf2, pSmad3C, Nrf2/pNrf2, HO-1, pSmad3C/3L, c-Myc, and p21 were detected. Exposure of HuH-7 cells to TGF-β₁ enhanced the cell proliferation, migration, invasion, and ROS production. Pretreatment with AS-IV (5, 10, and 20 μM) significantly reduced the cell proliferation, migration, invasion, and ROS production in HuH-7 cells. Furthermore, AS-IV increased the expressions of Nrf2/pNrf2, HO-1, pSmad3C, and p21, meanwhile reduced the expressions of pSmad3L and c-Myc. In conclusion, our study suggested that AS-IV inhibit HuH-7 cells migration and invasion, which related to activate Nrf2/HO-1 pathway, up-regulation pSmad3C/p21 pathway, and down-regulation pSmad3L/c-Myc pathway. The present research supports the notion that AS-IV may be a latent agent for the treatment of HCC.

Effect of Combined Perftoran and Indocyanine Green-Photodynamic Therapy on HypoxamiRs and OncomiRs in Lung Cancer Cells

Indocyanine green (ICG) is a nontoxic registered photosensitizer used as a diagnostic tool and for photodynamic therapy (PDT). Hypoxia is one the main factors affecting PDT efficacy. Perfluorodecalin emulsion (Perftoran®) is a known oxygen carrier. This study investigated the effect of Perftoran® on ICG/PDT efficacy in presence and absence of Perftoran® via evaluation of phototoxicity by MTT; hypoxia estimation by pimonidazole, HIF-1α/β by ELISA, and 17 miRNAs (tumor suppressors, oncomiRs, and hypoxamiRs) were analyzed by qPCR. Compared to ICG/PDT, Perftoran®/ICG/PDT led to higher photocytotoxicity, inhibited pimonidazole hypoxia adducts, inhibited HIF-1α/β concentrations, induced the expression of tumor-suppressing miRNAs let-7b/d/f/g, and strongly inhibited the pro-hypoxia miRNA let-7i. Additionally, Perftoran®/ICG/PDT suppressed the expression of the oncomiRs miR-155, miR-30c, and miR-181a and the hypoxamiRs miR-210 and miR-21 compared to ICG/PDT. In conclusion, Perftoran® induced the phototoxicity of ICG/PDT and inhibited ICG/PDT-hypoxia via suppressing HIF-α/β, miR-210, miR-21, let-7i, miR-15a, miR-30c, and miR-181a and by inducing the expression of let-7d/f and miR-15b.

Advances in Nanoliposomes for the Diagnosis and Treatment of Liver Cancer

The mortality rate of liver cancer is gradually increasing worldwide due to the increasing risk factors such as fatty liver, diabetes, and alcoholic cirrhosis. The diagnostic methods of liver cancer include ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), among others. The treatment of liver cancer includes surgical resection, transplantation, ablation, and chemoembolization; however, treatment still faces multiple challenges due to its insidious development, high rate of recurrence after surgical resection, and high failure rate of transplantation. The emergence of liposomes has provided new insights into the treatment of liver cancer. Due to their excellent carrier properties and maneuverability, liposomes can be used to perform a variety of functions such as aiding in imaging diagnoses, combinatorial therapies, and integrating disease diagnosis and treatment. In this paper, we further discuss such advantages.

Evaluation of photodynamic effect of Indocyanine green (ICG) on the colon and glioblastoma cancer cell lines pretreated by cold atmospheric plasma

BACKGROUND

Cold Atmospheric Plasma (CAP) has been proposed as a new approach based on its anticancer potential. However, its biological effects in combination with other physical modalities may also enhance efficiency and expand the applicability of the CAP method Photodynamic Therapy (PDT) may be improved by the use of indocyanine green (ICG) photosensitizer with absorption wavelength in the near infrared region to allow for deeper treatment depth.. In this study, the effectiveness of cold atmospheric helium plasma (He-CAP) as a pretreatment on the efficiency of ICG mediated PDT was investigated.

METHODS AND MATERIAL

First, toxicity of different concentrations of ICG on HT-29 and U-87MG cell lines was examined for 24 h. IC₁₀ and IC₃₀ of ICG were determined and then cells were treated with this ICG concentrations with different plasma radiation doses and light exposures for 48 h. Finally, MTT assay was performed for all treatment groups. The experiments were repeated at least 4 times at each group for two cell lines, separately. In order to compare the results, several indicators such as treatment efficiency, synergistic ratio, and the amount of optical exposure required for 50% cell death (ED₅₀) were also defined. Finally, SPSS 20 software is used for statistical analysis of data.

RESULTS

Pretreatment with CAP could significantly reduce cell survival in both cell lines (P<0.05). Also concentrations, irradiation time with CAP, and appropriate light exposure in both cell lines increased therapeutic efficiency compared to either treatment alone (P<0.05). While increasing the efficiency of photodynamic therapy varied between the two cell lines, the improvement in the PDT process was demonstrated by pretreatment with CAP.

CONCLUSION

Synergistic effect in the cell death with PDT were observed following He-CAP treatment and the results indicated that pretreatment with He-CAP improves the efficiency of photodynamic therapy.

Potential of Cyanine Derived Dyes in Photodynamic Therapy

Photodynamic therapy (PDT) is a method of cancer treatment that leads to the disintegration of cancer cells and has developed significantly in recent years. The clinically used photosensitizers are primarily porphyrin, which absorbs light in the red spectrum and their absorbance maxima are relatively short. This review presents group of compounds and their derivatives that are considered to be potential photosensitizers in PDT. Cyanine dyes are compounds that typically absorb light in the visible to near-infrared-I (NIR-I) spectrum range (750-900 nm). This meta-analysis comprises the current studies on cyanine dye derivatives, such as indocyanine green (so far used solely as a diagnostic agent), heptamethine and pentamethine dyes, squaraine dyes, merocyanines and phthalocyanines. The wide array of the cyanine derivatives arises from their structural modifications (e.g., halogenation, incorporation of metal atoms or organic structures, or synthesis of lactosomes, emulsions or conjugation). All the following modifications aim to increase solubility in aqueous media, enhance phototoxicity, and decrease photobleaching. In addition, the changes introduce new features like pH-sensitivity. The cyanine dyes involved in photodynamic reactions could be incorporated into sets of PDT agents.

Near-Infrared Fluorescence Imaging and Photodynamic Therapy for Liver Tumors

Surgery with fluorescence equipment has improved to treat the malignant viscera, including hepatobiliary and pancreatic neoplasms. In both open and minimally invasive surgeries, optical imaging using near-infrared (NIR) fluorescence is used to assess anatomy and function in real time. Here, we review a variety of publications related to clinical applications of NIR fluorescence imaging in liver surgery. We have developed a novel nanoparticle (indocyanine green lactosome) that is biocompatible and can be used for imaging cancer tissues and also as a drug delivery system. To date, stable particles are formed in blood and have an ~10–20 h half-life. Particles labeled with a NIR fluorescent agent have been applied to cancer tissues by the enhanced permeability and retention effect in animals. Furthermore, this article reviews recent developments in photodynamic therapy with NIR fluorescence imaging, which may contribute and accelerate the innovative treatments for liver tumors.

In-vitro investigation of cold atmospheric plasma induced photodynamic effect by Indocyanine green and Protoporphyrin IX

BACKGROUND

Photodynamic therapy (PDT) is one of the non-invasive methods for the treatment of superficial malignant cancers. One of the limiting challenges of PDT is the hypoxic conditions during treatment that reduces PDT Efficiency. Because of ROS and free radicals in plasma flame output, Cold atmospheric plasma (CAP) may improve treatment efficiency. In this study, the effect of plasma-induced photodynamic effect of two Photosensitizers (PSs) include Indocyanine green (ICG) and Protoporphyrin IX (PPIX) on two cell lines (MCF-7 and HT-29) was investigated.

METHODS

First, toxicity of different concentrations of PSs (5-50 μM) were examined on cell lines. After that, we surveyed low toxicity of PSs concentrations with different plasma radiation doses. To quantitative of cell survival, MTT assay was performed after 48 h. Finally, in order to statistical analysis of data, we used SPSS software (version 20) and also in order to better comparison the results, we used indexes such as Plasma sensitivity index and Synergism index.

RESULTS

The results indicate that in most irradiant conditions; for ICG + CAP group, PSI > 1 and SI < 1 in the both of cell line (P < 0.05). Also for PPIX + CAP group in most irradiant conditions, only in the HT-29 cell line can it be said with certainty that both indexes (PSI and SI) are higher than 1 (P < 0-05).

CONCLUSION

The results show that the plasma-induced photodynamic therapy with ICG and PPIX has more effective results on MCF-7 (breast cancer) and HT-29 (colon cancer) cell line, respectively. Also, the synergistic effect was observed only for PPIX in the HT-29 cell line.

Application of photodynamic therapy for liver malignancies

Liver malignancies include primary and metastatic tumors. Limited progress has been achieved in improving the survival rate of patients with advanced stage liver cancer and who are unsuitable for surgery. Apart from surgery, chemoradiotherapy, trans-arterial chemoembolization and radiofrequency ablation, a novel therapeutic modality is needed for the clinical treatment of liver cancer. Photodynamic therapy (PDT) is a novel strategy for treating patients with advanced cancers; it uses a light-triggered cytotoxic photosensitizer and a laser light. PDT provides patients with a potential treatment approach with minimal invasion and low toxicity, that is, the whole course of treatment is painless, harmless, and repeatable. Therefore, PDT has been considered an effective palliative treatment for advanced liver cancers. To date, PDT has been used to treat hepatocellular carcinoma, cholangiocarcinoma, hepatoblastoma and liver metastases. Clinical outcomes reveal that PDT can be considered a promising treatment modality for all liver cancers to improve the quality and quantity of life of patients. Despite the advances achieved with this approach, several challenges still impede the application of PDT to liver malignancies. In this review, we focus on the recent advancements and discuss the future prospects of PDT in treating liver malignancies.

Near-infrared fluorescence imaging and photodynamic therapy with indocyanine green lactosomes has antineoplastic effects for gallbladder cancer

BACKGROUND: The diagnostic use and therapeutic effect of near infrared fluorescence (NIF) imaging and photodynamic therapy (PDT) was investigated for gallbladder cancer using indocyanine green (ICG)-lactosomes. RESULTS: PDT was toxic for NOZ cells treated with ICG-lactosomes. Fluorescence intensity in the tumor region of mice administered ICG-lactosomes, but not ICG alone, was higher than the healthy contralateral region ≥24 hours after injection. PDT exerted immediate and continuous phototoxic effects in NOZ implanted mice injected with ICG-lactosomes. Enhanced antitumor effects were observed in the twice irradiated group compared with the once irradiated group. METHOD: ICG or ICG-lactosomes were added to the human gallbladder cancer cell line NOZ followed by PDT and cell viability was measured. Mass spectrometry of ICG and ICG-lactosomes was performed after PDT. ICG or ICG-lactosomes were intravenously administered to BALB/c nude mice implanted subcutaneously with NOZ cells and fluorescence was evaluated by NIF imaging. Implanted tumors underwent PDT and antitumor effects were analyzed after performing irradiation once or twice in ICG-lactosome groups. CONCLUSIONS: ICG-lactosomes accumulated in xenograft tumors and PDT had an antitumor effect on these malignant tumors. NIF imaging with ICG-lactosomes and PDT may be useful diagnostic and/or therapeutic agents for gallbladder cancer.

A novel liver-specific fluorescent anti-cancer drug delivery system using indocyanine green

Indocyanine green (ICG) accumulates only in hepatocytes and their malignant counterpart, hepatocellular carcinoma (HCC). We have developed ICG-conjugated anti-cancer drugs and noted their significant accumulation in HCC cells both in vitro and in vivo. ICG-conjugated gemcitabine was less toxic to normal cells and it had superior anti-tumor action compared to gemcitabine alone in a subcutaneous tumor xenograft. ICG conjugation can provide a novel fluorescent drug delivery system for treatment of liver cancer and this system can be used to both diagnose and treat HCC.

Utilisation of antimicrobial photodynamic therapy as an adjunctive tool for open flap debridement in the management of chronic periodontitis: A randomized controlled clinical trial

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) has proved to be an effective adjunctive modality with potential benefits in the management of chronic periodontitis. The combination of photothermal and photodynamic effects of Indocyanine green (ICG) dye, when it is photoactivated with a diode laser of 810 nm wavelength, has been well documented in literature.

AIM

This study was conducted to evaluate whether a single session of antimicrobial photodynamic therapy using ICG dye-810 nm diode laser combination can provide a substantial benefit when it is utilised as an adjunct to open flap debridement (OFD) in the management of chronic periodontitis.

MATERIALS AND METHOD

Following thorough scaling and root planing, a comparative split mouth randomized controlled clinical trial was carried out on 20 recruited subjects who provided one test (OFD + aPDT) and one control site (OFD alone) each (total 40 treatment sites). The test group was subjected to a single episode of aPDT using ICG photosensitiser dye (1 mg/ml) activated with 810 nm diode laser. The laser was used in a continuous wave, non-contact mode at a power output of 100 mW applied for 30 s/spot (the total of 4 spots per tooth) and delivered by 400 μm fibre, to provide a fluence (energy density) value of 0.0125 J/cm² per spot and generate a total energy of 3 J. The following clinical parameters were assessed at baseline and 3 months: probing pocket depth (PPD), relative attachment level (RAL), relative gingival margin level (RGML), plaque index (PI), gingival index (GI), and gingival bleeding index (GBI). Intragroup and intergroup comparison was performed using paired t-test and independent samples t-test respectively.

RESULTS

Intragroup comparison revealed a statistically significant improvement from baseline visit (p < 0.05). Intergroup comparison showed a statistically significant improvement in RAL, RGML and GI in the test group (p < 0.05).

CONCLUSION

Utilisation of ICG dye activated with 810 nm diode laser, which mediated aPDT, has demonstrated surplus clinical improvement following OFD in the management of chronic periodontitis.

Innovative treatment for hepatocellular carcinoma (HCC)

Indocyanine green (ICG) is not new in the field of liver surgery. Early studies performed in the 1980s and 1990s revealed the value of the ICG clearance test in predicting post-hepatectomy morbidity and mortality. ICG clearance and retention tests are crucial for determining precise liver function before liver surgery and offer several benefits for safe surgery. Whereas ICG is well-known and has long history in medicine, recent progress in infrared light technology over the last decade has highlighted another feature of ICG. For example, ICG fluorescence-guided surgery may change the next generation of liver surgery. In the near future, ICG with near-infrared (NIR) light photodynamic therapy (PDT) is expected to become a new treatment method for hepatocellular carcinoma (HCC). Furthermore, several aspects of the mechanisms of ICG accumulation in HCC cells have been revealed by important basic research studies. New imaging technologies and mechanistic findings keep ICG in the spotlight. In this article, we review three recently described topics of ICG which may contribute to the development of innovative and new treatments method for HCC, fluorescence-guided surgery, mechanism of ICG accumulation in HCC cells, PDT for HCC.

Stability and degradation of indocyanine green in plasma, aqueous solution and whole blood

Fluorescence-based imaging has evolved into an important technology during recent years. Specifically indocyanine green (ICG) has invaded most fields of diagnostic and interventional medicine. Considering the numerous advantages of the substance like the rapid degradation and rare adverse reactions, ICG is currently the most commonly used fluorescing agent. High-performance liquid chromatography (HPLC) was used for measuring absorbance and fluorescence of ICG and its potential degradation compounds. Stability and degradation were evaluated under light exposure or in darkness at various temperatures. Under these conditions, degradation of ICG was evaluated over a period of 11 days. Additional, stability measurements of ICG were performed in EDTA whole blood samples at 37 °C incubation temperature while monitoring. Furthermore, we used mass spectrometric (MS) and nuclear magnetic resonance (NMR) analyses for the identification of supposed ICG degradation compound. Potential quenching effect of ICG was examined in aqueous and plasma solutions at concentrations ranging from 0.01-100 μg ml-1. When diluted in water and stored at 4 °C in the dark, ICG is stable for three days with only 20% of fluorescence intensity lost in this time-span. ICG incubated at 37 °C in whole blood under light exposure is stable for 5 h. In our study we observed the degradation of ICG into two degradation compounds with a mass of m/z 785.32 and m/z 1501.57, respectively. Based on our observations we suggest that ICG should be used within one or two days after preparation, if the ICG solution is stored at 4 °C.

A novel nano-superparamagnetic agent for photodynamic and photothermal therapies: An in-vitro study

BACKGROUND

In this study, iron oxide nanoparticles (SPIONs) were synthesized and coated by GA (SG) and then SG was encapsulated by ICG (SGI). After identifying specifications and cytotoxicity of the agents, the potential of SGI for photodynamic therapy (PDT) and photothermal therapy (PTT) was studied.

METHODS

An SGI size of 12-13 nm was determined by TEM images and its zeta potential was measured at -23.8 ± 5.8 mV. MCF-7 and HT-29 cells were exposed to a non-coherent light source at a wavelength of 730 nm and a range of 3.9-124.8 J/cm² under two different concentrations of agents. The viability of treated cells was determined via MTT assay. To analyze the effects of different irradiation conditions, some indices such as Coefficient of Light Effect, Synergism Index, Addition Ratio, Treatment Efficacy and ED₅₀ were defined.

RESULTS

Cell survival at the highest power of irradiation in the absence of any agent was decreased to 93% and 73% for HT-29 and MCF-7, respectively. In both cell lines, the cellular survival dropped by increasing the light source intensity. The maximum cell death recorded for SG, ICG and SGI was 63 ± 2%, 63 ± 2% and 21 ± 2% for MCF-7 cells and 67 ± 2%, 78 ± 1% and 53 ± 1% for HT-29 cells, respectively.

CONCLUSION

SGI had a significant photodynamic and photothermal effect on cells. This is a promising outcome, which can help enhance the effectiveness of a minimally invasive treatment. Moreover, SPIONs can be used to apply magnetic hyperthermia or act as a contrast agent in MRI images.

Leveraging Engineering of Indocyanine Green-Encapsulated Polymeric Nanocomposites for Biomedical Applications

In recent times, photo-induced therapeutics have attracted enormous interest from researchers due to such attractive properties as preferential localization, excellent tissue penetration, high therapeutic efficacy, and minimal invasiveness, among others. Numerous photosensitizers have been considered in combination with light to realize significant progress in therapeutics. Along this line, indocyanine green (ICG), a Food and Drug Administration (FDA)-approved near-infrared (NIR, >750 nm) fluorescent dye, has been utilized in various biomedical applications such as drug delivery, imaging, and diagnosis, due to its attractive physicochemical properties, high sensitivity, and better imaging view field. However, ICG still suffers from certain limitations for its utilization as a molecular imaging probe in vivo, such as concentration-dependent aggregation, poor in vitro aqueous stability and photodegradation due to various physicochemical attributes. To overcome these limitations, much research has been dedicated to engineering numerous multifunctional polymeric composites for potential biomedical applications. In this review, we aim to discuss ICG-encapsulated polymeric nanoconstructs, which are of particular interest in various biomedical applications. First, we emphasize some attractive properties of ICG (including physicochemical characteristics, optical properties, metabolic features, and other aspects) and some of its current limitations. Next, we aim to provide a comprehensive overview highlighting recent reports on various polymeric nanoparticles that carry ICG for light-induced therapeutics with a set of examples. Finally, we summarize with perspectives highlighting the significant outcome, and current challenges of these nanocomposites.

Near-infrared photothermal/photodynamic therapy with indocyanine green induces apoptosis of hepatocellular carcinoma cells through oxidative stress

Indocyanine green (ICG) is a photothermal agent, photosensitizer, and fluorescence imaging probe which shows specific accumulation in hepatocellular carcinoma (HCC) cells. We recently developed a photodynamic therapy (PDT) using ICG and near-infrared (NIR) laser as a new anti-cancer treatment for HCC. However, the molecular mechanism underlying this effect needs to be elucidated. HuH-7 cells, a well-differentiated human HCC cell line, were transplanted subcutaneously into BALB/c-nu/nu mice for in vivo experiment. ICG was administered 24 h before NIR irradiation. The irradiation was performed at three tumor locations by 823-nm NIR laser on days 1 and 7. The temperature of HuH-7 xenografts increased to 48.5 °C 3 minutes after ICG-NIR irradiation start. Reactive oxygen species (ROS) production was detected after ICG-NIR irradiation both in vitro and in vivo. There was certain anti-tumor effect and ROS production even under cooling conditions. Repeated NIR irradiation increased the cell toxicity of ICG-NIR therapy; the mean tumor volume on day 9 was significantly smaller after ICG-NIR irradiation compared to tumor without irradiation (87 mm³ vs. 1332 mm³; p = 0.01) in HCC mice xenografts model. ICG-NIR therapy induced apoptosis in HCC cells via a photothermal effect and oxidative stress. Repeated ICG-NIR irradiation enhanced the anti-tumor effect.

Near-infrared fluorescence imaging and photodynamic therapy with indocyanine green lactosome has antineoplastic effects for hepatocellular carcinoma

Background

Anticancer agents and operating procedures have been developed for hepatocellular carcinoma (HCC) patients, but their prognosis remains poor. It is necessary to develop novel diagnostic and therapeutic strategies for HCC to improve its prognosis. Lactosome is a core-shell-type polymeric micelle, and enclosing labeling or anticancer agents into this micelle enables drug delivery. In this study, we investigated the diagnostic and therapeutic efficacies of indocyanine green (ICG)-loaded lactosome for near-infrared fluorescence (NIF) imaging and photodynamic therapy (PDT) for HCC.

Methods

The human HCC cell line HuH-7 was treated with ICG or ICG-lactosome, followed by PDT, and the cell viabilities were measured (in vitro PDT efficiency). For NIF imaging, HuH-7 cells were subcutaneously transplanted into BALB/c nude mice, followed by intravenous administration of ICG or ICG-lactosome. The transplanted animals were treated with PDT, and the antineoplastic effects were analyzed (in vivo PDT efficiency).

Results

PDT had toxic effects on HuH-7 cells treated with ICG-lactosome, but not ICG alone. NIF imaging revealed that the fluorescence of tumor areas in ICG-lactosome-treated animals was higher than that of contralateral regions at 24 h after injection and thereafter. PDT exerted immediate and continuous phototoxic effects in the transplanted mice treated with ICG-lactosome.

Conclusions

Our results demonstrate that ICG-lactosome accumulated in xenograft tumors, and that PDT had antineoplastic effects on these malignant implants. NIF imaging and PDT with ICG-lactosome could be useful diagnostic and/or therapeutic strategies for HCC.

Evaluation of fluorescence imaging with indocyanine green in hepatocellular carcinoma

Background

We hypothesized that indocyanine green (ICG) fluorescence patterns using Clairvivo OPT in resected liver specimens could confirm hepatocellular carcinoma (HCC) better than earlier commercial imaging systems. This preclinical trial evaluated the effectiveness of fluorescence imaging as an intraoperative cancer navigation tool.

Methods

ICG fluorescence images of resected specimens from 190 patients with HCC were classified into two groups according to whether high fluorescence was seen in the HCC (high cancerous [HC] group) or in the surrounding liver tissue (high surrounding [HS] group). The HC and HS groups were sub-classified into whole and partial types and whole and ring types, respectively.

Results

The HC group had significantly higher prevalence of esophageal or gastric varices, and worse liver function than patients in the HS group. The HC group also had a higher percentage of limited resection cases than did the HS group. Cirrhotic liver histology was significantly more common in the HC group than in the HS group. Multivariate analysis revealed that the HC group was a predictive factor for cirrhosis in HCC patients. Among the HC patients, a higher percentage of well-differentiated HCC cases were seen in the partial-type subgroup than in the whole-type subgroup (23/48 (48 %) vs. 7/68 (10 %)). In the HS group, the ring-type subgroup had a higher percentage of poorly differentiated HCC cases than did the whole-type subgroup (6/37 (16 %) vs. 0/37 (0 %)).

Conclusion

Tumor differentiation and fibrosis in the non-cancerous liver parenchyma could affect ICG fluorescence imaging in HCC. ICG fluorescence imaging may be a good indication for fibrosis stage. In future, we will try to evaluate fluorescence imaging with ICG for intraoperative cancer navigation in HCC, using a portable near-infrared fluorescence imaging system.

Photoacoustic tomography of human hepatic malignancies using intraoperative indocyanine green fluorescence imaging

Recently, fluorescence imaging following the preoperative intravenous injection of indocyanine green has been used in clinical settings to identify hepatic malignancies during surgery. The aim of this study was to evaluate the ability of photoacoustic tomography using indocyanine green as a contrast agent to produce representative fluorescence images of hepatic tumors by visualizing the spatial distribution of indocyanine green on ultrasonographic images. Indocyanine green (0.5 mg/kg, intravenous) was preoperatively administered to 9 patients undergoing hepatectomy. Intraoperatively, photoacoustic tomography was performed on the surface of the resected hepatic specimens (n = 10) under excitation with an 800 nm pulse laser. In 4 hepatocellular carcinoma nodules, photoacoustic imaging identified indocyanine green accumulation in the cancerous tissue. In contrast, in one hepatocellular carcinoma nodule and five adenocarcinoma foci (one intrahepatic cholangiocarcinoma and 4 colorectal liver metastases), photoacoustic imaging delineated indocyanine green accumulation not in the cancerous tissue but rather in the peri-cancerous hepatic parenchyma. Although photoacoustic tomography enabled to visualize spatial distribution of ICG on ultrasonographic images, which was consistent with fluorescence images on cut surfaces of the resected specimens, photoacoustic signals of ICG-containing tissues decreased approximately by 40% even at 4 mm depth from liver surfaces. Photoacoustic tomography using indocyanine green also failed to identify any hepatocellular carcinoma nodules from the body surface of model mice with non-alcoholic steatohepatitis. In conclusion, photoacoustic tomography has a potential to enhance cancer detectability and differential diagnosis by ultrasonographic examinations and intraoperative fluorescence imaging through visualization of stasis of bile-excreting imaging agents in and/or around hepatic tumors. However, further technical advances are needed to improve the visibility of photoacoustic signals emitted from deeply-located lesions.

Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green-photodynamic eye imaging

BACKGROUND

To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated.

METHODS

ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation.

RESULTS

Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%.

CONCLUSION

ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection.

Mechanistic background and clinical applications of indocyanine green fluorescence imaging of hepatocellular carcinoma

BACKGROUND

Although clinical applications of intraoperative fluorescence imaging of liver cancer using indocyanine green (ICG) have begun, the mechanistic background of ICG accumulation in the cancerous tissues remains unclear.

METHODS

In 170 patients with hepatocellular carcinoma cells (HCC), the liver surfaces and resected specimens were intraoperatively examined by using a near-infrared fluorescence imaging system after preoperative administration of ICG (0.5 mg/kg i.v.). Microscopic examinations, gene expression profile analysis, and immunohistochemical staining were performed for HCCs, which showed ICG fluorescence in the cancerous tissues (cancerous-type fluorescence), and HCCs showed fluorescence only in the surrounding non-cancerous liver parenchyma (rim-type fluorescence).

RESULTS

ICG fluorescence imaging enabled identification of 273 of 276 (99%) HCCs in the resected specimens. HCCs showed that cancerous-type fluorescence was associated with higher cancer cell differentiation as compared with rim-type HCCs (P < 0.001). Fluorescence microscopy identified the presence of ICG in the canalicular side of the cancer cell cytoplasm, and pseudoglands of the HCCs showed a cancerous-type fluorescence pattern. The ratio of the gene and protein expression levels in the cancerous to non-cancerous tissues for Na(+)/taurocholate cotransporting polypeptide (NTCP) and organic anion-transporting polypeptide 8 (OATP8), which are associated with portal uptake of ICG by hepatocytes that tended to be higher in the HCCs that showed cancerous-type fluorescence than in those that showed rim-type fluorescence.

CONCLUSIONS

Preserved portal uptake of ICG in differentiated HCC cells by NTCP and OATP8 with concomitant biliary excretion disorders causes accumulation of ICG in the cancerous tissues after preoperative intravenous administration. This enables highly sensitive identification of HCC by intraoperative ICG fluorescence imaging.