Fluorescent detection of peritoneal metastasis in human colorectal cancer using 5-aminolevulinic acid

5-aminolevulinic acid induced photodynamic reactions in diagnosis and therapy for female lower genital tract diseases

Since the patients suffering from female lower genital tract diseases are getting younger and younger and the human papilloma virus (HPV) infection is becoming more widespread, the novel non-invasive precise modalities of diagnosis and therapy are required to remain structures of the organ and tissue, and fertility as well, by which the less damage to normal tissue and fewer adverse effects are able to be achieved. In all nucleated mammalian cells, 5-Aminolevulinic acid (5-ALA) is an amino acid that occurs spontaneously, which further synthesizes in the heme biosynthetic pathway into protoporphyrin IX (PpIX) as a porphyrin precursor and photosensitizing agent. Exogenous 5-ALA avoids the rate-limiting step in the process, causing PpIX buildup in tumor tissues. This tumor-selective PpIX distribution after 5-ALA application has been used successfully for tumor photodynamic diagnosis (PDD) and photodynamic therapy (PDT). Several ALA-based drugs have been used for ALA-PDD and ALA-PDT in treating many (pre)cancerous diseases, including the female lower genital tract diseases, yet the ALA-induced fluorescent theranostics is needed to be explored further. In this paper, we are going to review the studies of the mechanisms and applications mainly on ALA-mediated photodynamic reactions and its effectiveness in treating female lower genital tract diseases.

Photodynamic Diagnosis and Therapy in Non-Muscle-Invasive Bladder Cancer

Bladder cancer (BC) possesses distinct molecular profiles that influence progression depending on its biological nature and delivered treatment intensity. Muscle-invasive BC (MIBC) and non-MIBC (NMIBC) demonstrate great intrinsic heterogeneity regarding different prognoses, survival, progression, and treatment outcomes. Transurethral resection of bladder tumor (TURBT) is the standard of care in treating NMIBC and serves both diagnostic and therapeutic purposes despite the prevalent recurrence and progression among many patients. In particular, flat urothelial carcinoma in situ and urothelial carcinoma with lamina propria invasion are the major precursors of MIBC. A new-generation photosensitizer, 5-Aminolevulinic acid (5-ALA), demonstrates high tumor specificity by illuminating the tumor lesion with a specific wavelength of light to produce fluorescence and has been studied for photodynamic diagnosis to detect precise tumor areas by TURBT. Additionally, it has been applied for treatment by producing its cytotoxic reactive oxygen species, as well as screening for urological carcinomas by excreting porphyrin in the blood and urine. Moreover, 5-ALA may contribute to screening before and after TURBT in NMIBC. Here, we summarize the updated evidence and ongoing research on photodynamic technology for NMIBC, providing insight into the potential for improving patient outcomes.

Lymphatic flow mapping during colon cancer surgery using indocyanine green fluorescence imaging

With the development of surgical technology, indocyanine green (ICG) fluorescence navigation systems may be useful in various areas of colorectal surgery, including tumor location confirmation, bowel perfusion, ureter identification, and lymph node mapping. This review provides an overview of the current status of ICG-based navigation surgery in colorectal surgery, emphasizing its role in lymphatic flow mapping. This state-of-the-art approach will allow for appropriate oncological surgeries in the field of colorectal cancer and improve the patient's prognosis.

Comparison of chlorin-e6 detection efficiency by video systems with excitation wavelengths of 405nm and 635nm

BACKGROUND

Fluorescence diagnostics with two different wide field-of-view imaging systems with fluorescence excitation at 405 nm and 635 nm, respectively, were compared. Both systems include fluorescence quantification and experimental geometry normalization algorithms.

METHODS

A newly developed system with an excitation wavelength of 405 nm was tested on intralipid fluorescent tumor phantoms with chlorin-e6. Both, this new system and a second existing system with an excitation wavelength of 635 nm, were used for fluorescent diagnosis in six patients with basal cell carcinoma and cancer of the oral mucosa. For PDT, a red diode laser with a wavelength of 660 nm was used for all 6 patients. One patient received an additional irradiation using the red LED source of the new system RESULTS: The boundaries of the lesions and the fluorescence intensity were successfully determined by both video systems.

CONCLUSIONS

Both fluorescence imaging approaches showed comparable contrast between diseased and healthy tissues. For oral mucosal cancer, a system with violet fluorescence excitation, bispectral frame analysis, and time-resolved background suppression showed better contrast between the tumor and normal tissue and effective elimination of autofluorescence. Moreover, both systems provided efficient quantification of fluorescence and gave fluorescence indices that were weakly dependent on the distance between the device and the tissue.

Brain-derived neurotrophic factor overexpression in taste buds diminishes chemotherapy induced taste loss

Vismodegib is used in patients suffering from advanced basal cell carcinoma (BCC), but 100% of the patients taking it report dysgeusia and 50% discontinue the treatment. Treatment with neurotrophic factors can stimulate neuronal survival and functional improvement in injured organs. Here, we analysed novel transgenic mouse lines in which brain-derived neurotrophic factor (BDNF) is overexpressed in taste buds, to examine whether higher levels of BDNF would reduce or prevent negative side effects of vismodegib in the taste system. BDNF plays crucial roles for development, target innervation, and survival of gustatory neurons and taste buds. The behavioural test in this study showed that vehicle-treated wild-type mice prefered 10 mM sucrose over water, whereas vismodegib treatment in wild-type mice caused total taste loss. Gustducin-BDNF mice had a significantly increased preference for low concentration of sucrose solution over water compared to wild-type mice, and most importantly the transgenic mice were able to detect low concentrations of sucrose following vismodegib treatment. We evaluated taste cell morphology, identity, innervation and proliferation using immunohistochemistry. All drug-treated mice exhibited deficits, but because of a possible functional upcycled priming of the peripheral gustatory system, GB mice demonstrated better morphological preservation of the peripheral gustatory system. Our study indicates that overexpression of BDNF in taste buds plays a role in preventing degeneration of taste buds. Counteracting the negative side effects of vismodegib treatment might improve compliance and achieve better outcome in patients suffering from advanced BCC.

Objective Methods of 5-Aminolevulinic Acid-Based Endoscopic Photodynamic Diagnosis Using Artificial Intelligence for Identification of Gastric Tumors

Positive diagnoses of gastric tumors from photodynamic diagnosis (PDD) images after the administration of 5-aminolevulinic acid are subjectively identified by expert endoscopists. Objective methods of tumor identification are needed to reduce potential misidentifications. We developed two methods to identify gastric tumors from PDD images. Method one was applied to segmented regions in the PDD endoscopic image to determine the region in LAB color space to be attributed to tumors using a multi-layer neural network. Method two aimed to diagnose tumors and determine regions in the PDD endoscopic image attributed to tumors using the convoluted neural network method. The efficiencies of diagnosing tumors were 77.8% (7/9) and 93.3% (14/15) for method one and method two, respectively. The efficiencies of determining tumor region defined as the ratio of the area were 35.7% (0.0–78.0) and 48.5% (3.0–89.1) for method one and method two, respectively. False-positive rates defined as the ratio of the area were 0.3% (0.0–2.0) and 3.8% (0.0–17.4) for method one and method two, respectively. Objective methods of determining tumor region in 5-aminolevulinic acid-based endoscopic PDD were developed by identifying regions in LAB color space attributed to tumors or by applying a method of convoluted neural network.

Fluorescence Molecular Targeting of Colon Cancer to Visualize the Invisible

Colorectal cancer (CRC) is a common cause of cancer and cancer-related death. Surgery is the only curative modality. Fluorescence-enhanced visualization of CRC with targeted fluorescent probes that can delineate boundaries and target tumor-specific biomarkers can increase rates of curative resection. Approaches to enhancing visualization of the tumor-to-normal tissue interface are active areas of investigation. Nonspecific dyes are the most-used approach, but tumor-specific targeting agents are progressing in clinical trials. The present narrative review describes the principles of fluorescence targeting of CRC for diagnosis and fluorescence-guided surgery with molecular biomarkers for preclinical or clinical evaluation.

Design of a Surgical Pen-Type Probe for Real-Time Indocyanine Green Fluorescence Emission Diagnosis

The advantage of handheld type surgical microscope is that the size of the probe is small and light, and that both the working distance (15–30 cm) and field of view (30 deg) can be adjusted. The shortness working distance will minimize the loss of light source energy. However, the currently developed handheld type surgical microscope is still large, heavy, and uses relatively high energy (600 mW/cm2). To address the aforementioned problems, this study aimed to develop a pen-type surgical fluorescence microscope that is compact, portable, and has an adjustable beam angle and working distance. These features enable real-time diagnosis. The pen-type probe consists of a laser diode, CMOS camera, light source brightness control device, filter, and power switch. The IR-cut filter inside the CMOS camera was removed to facilitate transmission of the fluorescence emission wavelength. In addition, a long-pass filter was attached to the camera so that the external light source was blocked and only the fluorescence emission wavelength was allowed to pass through. The performance of the pen-type probe was tested through a large animal experiment. Indocyanine green (2.5 mg/kg) was injected into a pig's vein. Fluorescence emission of 805-830 nm was achieved by irradiating an external light source (785 nm and 4 mW/cm2), and liver-uptake occurred after 2.4 min. The designed pen-type probe was capable of sufficiently fluorescence expression through low-energy irradiation, and the pen-type probe is small and light and easy to handle by hand because both the pen-based laser device and the camera device are integrated. In addition, it is easy to adjust the working distance and field of view.

Alectinib treatment improves photodynamic therapy in cancer cell lines of different origin

Background

Photodynamic therapy with a photosensitizer such as protoporphyrin-IX, a light sensitive metabolite of heme synthesis, is a highly selective treatment for various carcinomas. In previous studies, we found a significant down regulation of the relevant enzyme ferrochelatase in gastrointestinal carcinomas leading to an accumulation of protoporphyrin-IX within the tumor cells. Recent studies showed that a novel anti-cancer drug, Alectinib, an orally available, highly selective, potent second-generation inhibitor of anaplastic lymphoma tyrosinkinase binds to ferrochelatase. Therefore, we were interested to see whether Alectinib treatment might lead to an accumulation of protoporphyrin IX.

Methods

Tumor cells of different origin were cultured, treated with LED-light and Alectinib. Results were gained by flow cytometry, immunohistochemistry and western blotting. Apoptosis was determined by flow cytometric analysis of Annexin V-FITC stained cells. In addition, cells were counterstained with propidium iodide to distinguish early apoptotic cells and late apoptotic/necrotic cells.

Results

Here, we report that photodynamic treatment of tumor cell lines of different origin in combination with Alectinib increased protoporphyrin-IX specific fluorescence and concomitantly cell death.

Conclusions

The usage of Alectinib could be another step for enhancing the effectiveness of photodynamic therapy. Further experiments will show whether photodynamic therapy in combination with Alectinib could be a new strategy for the treatment of e.g. peritoneal disseminated carcinomas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08667-x.

Matrix metalloprotease-14 is a target enzyme for detecting peritoneal metastasis in gastric cancer

BACKGROUND

Accurate diagnosis of peritoneal metastasis in gastric cancer (GC) is important to determine the appropriate treatment. This study aimed to examine whether matrix metalloprotease-14 (MMP-14) was a candidate enzyme in fluorescence imaging for the diagnosis of peritoneal metastasis in GC.

METHODS

GC and normal peritoneal (NP) tissues from 96 and 20 patients, respectively were evaluated for MMP-14 expression. Live cell imaging of GC cell lines (NUGC4, MKN45, MKN74, HGC-27, and Kato-III) was performed using the MMP-14-activatable fluorescence probe; BODIPY-MMP. Furthermore, the overall survival (OS) was calculated in all patients (n = 96).

RESULTS

MMP-14 expression was significantly higher in GC tissues (median: 3.57 ng/mg protein; range:0.64-24.4 ng/mg protein) than in NP tissues (median: 1.34 ng/mg protein; median: 0.53-3.09 ng/mg protein) (P < 0.01). Receiver operating characteristic curves showed that the area under the curve, sensitivity, and specificity were 0.907, 84.4%, and 90.0%, respectively. In live cell imaging using the BODIPY-MMP, fluorescence was observed in five GC cell lines. In the analysis of OS, the high expression of the MMP-14 group had a significantly poorer OS rate than the low expression of the MMP-14 group (P = 0.02). In the multivariate analyses, MMP-14 expression was an independent risk factor for OS (hazard ratio: 2.33; 95 % confidence interval: 1.05-5.45; P = 0.04).

CONCLUSION

MMP-14 is a promising enzyme in intraoperative fluorescence imaging for peritoneal metastasis in GC, especially in patients with poor prognosis.

A Surgical Pen-Type Probe Design for Real-Time Optical Diagnosis of Tumor Status Using 5-Aminolevulinic Acid

A surgical microscope is large in size, which makes it impossible to be portable. The distance between the surgical microscope and the observation tissue is 15–30 cm, and the adjustment range of the right and left of the camera is a maximum of 30°. Therefore, the surgical microscope generates an attenuation (above 58%) of irradiation of the optical source owing to the long working distance (WD). Moreover, the observation of tissue is affected because of dazzling by ambient light as the optical source power is strong (55 to 160 mW/cm²). Further, observation blind spot phenomena will occur due to the limitations in adjusting the right and left of the camera. Therefore, it is difficult to clearly observe the tumor. To overcome these problems, several studies on the handheld surgical microscope have been reported. In this study, a compact pen-type probe with a portable surgical microscope is presented. The proposed surgical microscope comprises a small and portable pen-type probe that can adjust the WD between the probe and the observed tissue. In addition, it allows the adjustment of the viewing angle and fluorescence brightness. The proposed probe has no blind spots or optical density loss.

iMAP: A Web Server for Metabolomics Data Integrative Analysis

Metabolomics data analysis depends on the utilization of bioinformatics tools. To meet the evolving needs of metabolomics research, several integrated platforms have been developed. Our group has developed a desktop platform IP4M (integrated Platform for Metabolomics Data Analysis) which allows users to perform a nearly complete metabolomics data analysis in one-stop. With the extensive usage of IP4M, more and more demands were raised from users worldwide for a web version and a more customized workflow. Thus, iMAP (integrated Metabolomics Analysis Platform) was developed with extended functions, improved performances, and redesigned structures. Compared with existing platforms, iMAP has more methods and usage modes. A new module was developed with an automatic pipeline for train-test set separation, feature selection, and predictive model construction and validation. A new module was incorporated with sufficient editable parameters for network construction, visualization, and analysis. Moreover, plenty of plotting tools have been upgraded for highly customized publication-ready figures. Overall, iMAP is a good alternative tool with complementary functions to existing metabolomics data analysis platforms. iMAP is freely available for academic usage at https://imap.metaboprofile.cloud/ (License MPL 2.0).

5-aminolaevulinic acid (5-ALA) accumulates in GIST-T1 cells and photodynamic diagnosis using 5-ALA identifies gastrointestinal stromal tumors (GISTs) in xenograft tumor models

Gastrointestinal stromal tumor (GIST) diagnosis using conventional gastrointestinal endoscopy is difficult because such malignancies cannot be distinguished from other types of submucosal tumors. Photodynamic diagnosis (PDD) is based on the preferential uptake of photosensitizers by tumor tissues and its detection by fluorescence emission upon laser excitation. In this study, we investigated whether PDD using 5-aminolevulinic acid (5-ALA), a standard photosensitizer used worldwide, could be used for GIST diagnosis. 5-ALA is metabolized to endogenous fluorescent protoporphyrin IX (PpIX). We examined the accumulation of PpIX in GIST-T1 cells using flow cytometry and immunofluorescent staining. Furthermore, we established GIST-T1 xenograft mouse models and examined PpIX accumulation in the resultant tumors. PpIX accumulated in GIST-T1 cells and was localized mainly to lysosomes. PpIX accumulation was also observed in murine xenograft tumors. Moreover, tumor and normal tissues could be distinctly identified by relative PpIX fluorescence. Thus, our results demonstrated that PDD with 5-ALA has substantial clinical potential for GIST diagnosis.

Photodynamic Diagnosis and Therapy for Peritoneal Carcinomatosis from Gastrointestinal Cancers: Status, Opportunities, and Challenges

Selective accumulation of a photosensitizer and the subsequent response in only the light-irradiated target are advantages of photodynamic diagnosis and therapy. The limited depth of the therapeutic effect is a positive characteristic when treating surface malignancies, such as peritoneal carcinomatosis. For photodynamic diagnosis (PDD), adjunctive use of aminolevulinic acid- protoporphyrin IX-guided fluorescence imaging detects cancer nodules, which would have been missed during assessment using white light visualization only. Furthermore, since few side effects have been reported, this has the potential to become a vital component of diagnostic laparoscopy. A variety of photosensitizers have been examined for photodynamic therapy (PDT), and treatment protocols are heterogeneous in terms of photosensitizer type and dose, photosensitizer-light time interval, and light source wavelength, dose, and dose rate. Although several studies have suggested that PDT has favorable effects in peritoneal carcinomatosis, clinical trials in more homogenous patient groups are required to identify the true benefits. In addition, major complications, such as bowel perforation and capillary leak syndrome, need to be reduced. In the long term, PDD and PDT are likely to be successful therapeutic options for patients with peritoneal carcinomatosis, with several options to optimize the photosensitizer and light delivery parameters to improve safety and efficacy.

Photodynamic Diagnosis and Therapy for Peritoneal Carcinomatosis: Emerging Perspectives

Simple Summary

Peritoneal carcinomatosis, the formation of wide-spread metastases throughout the abdominal cavity, remains challenging to diagnose and treat. Photodynamic diagnosis and photodynamic therapy are promising approaches for the diagnosis and treatment of peritoneal carcinomatosis, which use photosensitizers for fluorescence detection or photochemical treatment of (micro) metastases. With the aim of highlighting the potential of this theranostic approach, this review outlines the clinical state of the art in the use of photodynamic diagnosis and therapy for peritoneal carcinomatosis, identifies the major challenges, and provides emerging perspectives from preclinical studies to address these challenges. We conclude that the development of novel illumination strategies and targeted photonanomedicines may aid in achieving more efficient cytoreductive surgery. In addition to combination treatments with chemo-, and radiotherapy, such approaches hold significant promise to improve the outlook of patients with peritoneal carcinomatosis.

Abstract

Peritoneal carcinomatosis occurs frequently in patients with advanced stage gastrointestinal and gynecological cancers. The wide-spread peritoneal micrometastases indicate a poor outlook, as the tumors are difficult to diagnose and challenging to completely eradicate with cytoreductive surgery and chemotherapeutics. Photodynamic diagnosis (PDD) and therapy (PDT), modalities that use photosensitizers for fluorescence detection or photochemical treatment of cancer, are promising theranostic approaches for peritoneal carcinomatosis. This review discusses the leading clinical trials, identifies the major challenges, and presents potential solutions to advance the use of PDD and PDT for the treatment of peritoneal carcinomatosis. While PDD for fluorescence-guided surgery is practically feasible and has achieved clinical success, large randomized trials are required to better evaluate the survival benefits. Although PDT is feasible and combines well with clinically used chemotherapeutics, poor tumor specificity has been associated with severe morbidity. The major challenges for both modalities are to increase the tumor specificity of the photosensitizers, to efficiently treat peritoneal microtumors regardless of their phenotypes, and to improve the ability of the excitation light to reach the cancer tissues. Substantial progress has been achieved in (1) the development of targeted photosensitizers and nanocarriers to improve tumor selectivity, (2) the design of biomodulation strategies to reduce treatment heterogeneity, and (3) the development of novel light application strategies. The use of X-ray-activated PDT during whole abdomen radiotherapy may also be considered to overcome the limited tissue penetration of light. Integrated approaches that take advantage of PDD, cytoreductive surgery, chemotherapies, PDT, and potentially radiotherapy, are likely to achieve the most effective improvement in the management of peritoneal carcinomatosis.

Hysteroscopic Photodynamic Diagnosis Using 5-Aminolevulinic Acid: A High-Sensitivity Diagnostic Method for Uterine Endometrial Malignant Diseases

STUDY OBJECTIVE

To examine the diagnostic accuracy of hysteroscopic photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5ALA) in patients with endometrial cancer and premalignant atypical endometrial hyperplasia.

DESIGN

A single-center, open-label, exploratory intervention study.

SETTING

University Hospital in Japan.

PATIENTS

Thirty-four patients who underwent hysteroscopic resection in the Department of Obstetrics and Gynecology at Keio University Hospital.

INTERVENTIONS

Patients were given 5ALA orally approximately 3 hours before surgery and underwent observation of the uterine cavity and endometrial biopsy using 5ALA-PDD during hysteroscopic resection. Specimens were diagnosed histopathologically and the diagnostic sensitivity and specificity of hysteroscopic 5ALA-PDD for malignancy in the uterine cavity was determined. Red (R), blue (B), and green (G) intensity values were determined from PDD images, and the relationships of histopathological diagnosis with these values were used to develop a model for objective diagnosis of uterine malignancy.

MEASUREMENTS AND MAIN RESULTS

Three patients were excluded from the study because of failure of the endoscope system. A total of 113 specimens were collected endoscopically. The sensitivity and specificity of 5ALA-PDD for diagnosis of malignancy in the uterine cavity were 93.8% and 51.9%, respectively. The R/B ratio in imaging analysis was highest in malignant lesions, followed by benign lesions and normal uterine tissue, with significant differences among these groups (p <.05). The R/B and G/B ratios were used in a formula for prediction of malignancy based on logistic regression and the area under the receiver operating characteristic curve for this formula was 0.838. At a formula cutoff value of 0.220, the sensitivity and specificity for diagnosis of malignant disease were 90.6% and 65.4%, respectively.

CONCLUSION

To our knowledge, this is the first study of the diagnostic accuracy of 5ALA-PDD for malignancies in the uterine cavity. Hysteroscopic 5ALA-PDD had higher sensitivity and identifiability of lesions. These findings suggest that hysteroscopic 5ALA-PDD may be useful for diagnosis of minute lesions.

First robot-assisted radical prostatectomy in a client-owned Bernese mountain dog with prostatic adenocarcinoma

OBJECTIVE

To describe robot-assisted radical prostatectomy (RARP) and report the short-term outcome of a dog with prostatic cancer treated with RARP.

STUDY DESIGN

Case report ANIMALS: Client-owned 6-year-old male-neutered Bernese mountain dog.

METHODS

Robot-assisted radical prostatectomy was performed with a daVinci Si Surgical System through a transperitoneal approach. An interfascial nerve-sparing approach was used to preserve the neurovascular bundles and increase the likelihood of postoperative urinary continence. Urinary continence was assessed by placing white cloth bedding in the kennel during hospitalization and by owners' observation at home.

RESULTS

The console time was 120 minutes, and the estimated intraoperative blood loss was 30 mL. No intraoperative complications were observed. The urinary catheter was removed after 7 days, at which point the dog urinated normally. Peritoneal carcinomatosis was diagnosed 43 days after surgery, and the dog was euthanized.

CONCLUSION

Robot-assisted radical prostatectomy was successfully completed in a dog with prostatic neoplasia and led to postoperative urinary continence.

CLINICAL SIGNIFICANCE

This single-case report provides evidence to justify further evaluation of RARP in dogs with prostatic neoplasms.

Objective tumor distinction in 5-aminolevulinic acid-based endoscopic photodynamic diagnosis, using a spectrometer with a liquid crystal tunable filter

Background

Recent improvement of the endoscopic system such as image enhancement has led to the better accuracy of the diagnosis of the gastric cancer. However, the objective and efficient detection method of the gastric cancer is still needed because the detection efficiency could sometimes be low due to the fact that the image enhancement diagnosis needs magnification for its full utilization. The photodynamic diagnosis (PDD) with oral intake of 5-aminolevulinic acid (5-ALA) has been widely used for the detection of the cancerous region for bladder cancer and glioblastoma. The application of the 5-ALA based PDD (5-ALA PDD) to the diagnosis of gastric cancer is recently reported. The efficiency of the detection is reported to be good, however, the objectivity of the method can be impaired by the photobleaching effect with fast decreasing of the intensity of the fluorescence under light exposure. In this article, we investigated the fluorescence spectrum of the gastric tumor and non-tumor mucosa of 5-ALA PDD and revealed the property of the photobleaching effect.

Methods

Example cases of PDD endoscopy of gastric tumor were investigated for cases of endoscopic submucosal dissection (ESD). Newly developed spectrometer using a spectrometer with a liquid crystal tunable filter was used for investigating the fluorescence spectrum of 5-ALA PDD. The assumed tumor region and non-tumor region in gastric mucosa were biopsied and the fluorescence spectrum was measured using the spectrometer consecutively several times, to estimate the photobleaching effect.

Results

The fluorescence spectrum has a primary peak at 630 nm, with a broad peak ranging from 660 to 700 nm. The 630 nm peak diminished quickly upon ultraviolet light exposure, whereas the broad peak from 660 to 700 nm diminished slowly. The sum of the altitudes at 660–700 nm, normalized to the altitude at 600 nm, was not as affected by the photobleaching effect as the 630 nm peak was, and can thus be used for 5-ALA-based PDD.

Conclusions

The 5-ALA PDD using the average fluorescence altitude of 660–700 nm instead of the peak altitude at 630 nm, is shown to be more effective in distinguishing between tumorous and non-tumorous tissues, because of the lower photobleaching effect at this specific spectral range. The finding is expected to greatly improve the objective diagnosis of gastrointestinal cancers by 5-ALA-based photodynamic diagnostic endoscopy.

PINPOINT® can be used for photodynamic diagnosis based on 5-aminolevulinic acid-induced protoporphyrinIX in gastric cancer surgery: Report of a case

•

We have reported the case that underwent laparoscopic total gastrectomy with photodynamic diagnosis based on 5-aminolevulinic acid induced protoporphyrinIX by using PINPOINT®.

•

PINPOINT®, a brightfield color fluorescence camera, could be used for 5-ALA-PDD.

•

Administration of 5-ALA through PTEG for a patient with pyloric stenosis was successfully performed.

Introduction

Photodynamic diagnosis (PDD) using 5-aminolevulinic acid (5-ALA) has been used as a diagnostic procedure for malignant diseases. Dedicated laparoscopes (e.g., an IMAGE1 Camera System®) are used for this procedure. We report a case treated with laparoscopic total gastrectomy with 5-ALA-PDD using the PINPOINT® system.

Presentation of case

A patient in his 80 s with diffuse-type gastric cancer with pyloric stenosis and ascites was admitted to our hospital. Double percutaneous transesophageal gastrotubing (dPTEG) for both gastric decompression and enteral nutrition and two cycles of preoperative chemotherapy with S-1 plus oxaliplatin were performed preoperatively.

Additionally, we preoperatively performed an ex vivo experiment that confirmed that the PINPOINT® system can be used to observed protoporphyrin IX (PpIX) fluorescence.

Three hours before surgery, 5-ALA hydrochloride was administered through dPTEG. Observation was performed by PINPOINT®, and Aladuck® was used as an excitation light source.

Peritoneal nodules and sampled lymph nodes with red fluorescence were observed by 5-ALA-PDD. Accordingly, we gave up a radical operation and laparoscopic total gastrectomy without systematic lymphadenectomy to improve anemia and release pyloric stenosis was performed. The patient’s postoperative course was uneventful.

Discussion

It is possible that the connection with each of the scopes and an exclusive light source (Aladuck®) enable the easy use of 5-ALA-PDD without dedicated laparoscopy.

It is expected that 5-ALA-PDD would show the further spread of gastrointestinal cancer if it could be performed with many types of laparoscopes.

Conclusion

We found that 5-ALA-PDD-guided surgery can be easily performed in a short time using the PINPOINT® system.

Evaluation of Aminolevulinic Acid-Derived Tumor Fluorescence Yields Disparate Results in Murine and Spontaneous Large Animal Models of Lung Cancer

Fluorescence guided surgery is an emerging technology that may improve accuracy of pulmonary resection for non-small cell lung cancer (NSCLC). Herein we explore optical imaging for NSCLC surgery using the well-studied protoporphyrin IX (PPIX)/5-aminiolevulinic acid (5-ALA) system. More specifically, we evaluate fluorescent patterns observed when using (1) commonly utilized in vitro and murine NSCLC models and with (2) spontaneous canine NSCLCs, which closely mimic human disease. Using flow cytometry and fluorescent microscopy, we confirmed that NSCLC models fluoresce after exposure to 5-ALA in vitro. High levels of fluorescence were similarly observed in murine tumors within 2 hours of systemic 5-ALA delivery. When evaluating this approach in spontaneous canine NSCLC, tumor fluorescence was observed in 6 of 7 canines. Tumor fluorescence, however, was heterogenous owing to intratumoral variations in cellularity and necrosis. Margin and lymph node detection was inaccurate. These data demonstrate the importance of incorporating reliable cancer models into preclinical evaluations of optical agents. Utilization of spontaneous large animal models of cancer may further provide an important intermediate in the path to human translation of optical contrast agents.

Rapid detection of metastatic lymph nodes of colorectal cancer with a gamma-glutamyl transpeptidase-activatable fluorescence probe

Rapid diagnosis of metastatic lymph nodes (mLNs) of colorectal cancer (CRC) is desirable either intraoperatively or in resected fresh specimens. We have developed a series of activatable fluorescence probes for peptidase activities that are specifically upregulated in various tumors. We aimed to discover a target enzyme for detecting mLNs of CRC. Among our probes, we found that gGlu-HMRG, a gamma-glutamyl transpeptidase (GGT)-activatable fluorescence probe, could detect mLNs. This was unexpected, because we have previously reported that gGlu-HMRG could not detect primary CRC. We confirmed that the GGT activity of mLNs was high, whereas that of non-metastatic lymph nodes and CRC cell lines was low. We investigated the reason why GGT activity was upregulated in mLNs, and found that GGT was induced under conditions of hypoxia or low nutritional status. We utilized this feature to achieve rapid detection of mLNs with gGlu-HMRG. GGT appears to be a promising candidate enzyme for fluorescence imaging of mLNs.

Design of Bifunctional Dendritic 5-Aminolevulinic Acid and Hydroxypyridinone Conjugates for Photodynamic Therapy

Iron chelators have recently attracted interest in the field of photodynamic therapy (PDT) owing to their role in enhancement of intracellular protoporphyrin IX (PpIX) generation induced by 5-aminolevulinic acid (ALA) via the biosynthetic heme cycle. Although ALA is widely used in PDT, cellular uptake of ALA is limited by its hydrophilicity. In order to improve ALA delivery and enhance the PpIX production, several dendrimers incorporating both ALA and 3-hydroxy-4-pyridinone (HPO) were synthesized. The ability of the dendrimers to enter cells and be metabolized to the PpIX photosensitizer was studied in several human cancer cell lines. The dendrimers were found to be significantly more efficient than ALA alone in PpIX production. The higher intracellular PpIX levels showed a clear correlation with enhanced cellular phototoxicity following light exposure. Dendritic derivatives are therefore capable of efficiently delivering both ALA and HPO, which act synergistically to amplify in vitro PpIX levels and enhance PDT efficacy.

Optimal timing of preoperative indocyanine green administration for fluorescent cholangiography during laparoscopic cholecystectomy using the PINPOINT® Endoscopic Fluorescence Imaging System

INTRODUCTION

The PINPOINT® Endoscopic Fluorescence Imaging System (Novadaq, Mississauga, Canada) allows surgeons to visualize the bile ducts during laparoscopic cholecystectomy. Surgeons can continue operation while confirming the bile ducts' fluorescence with a bright-field/color image. However, strong fluorescence of the liver can interfere with the surgery. Here, we investigated the optimal timing of indocyanine green administration to allow fluorescent cholangiography to be performed without interference from the liver fluorescence.

METHODS

A total of 72 patients who underwent laparoscopic cholecystectomy were included in this study. The timing of indocyanine green administration was set immediately before surgery and at 3, 6, 9, 12, 15, 18, and 24 h before surgery. The luminance intensity ratios of gallbladder/liver, cystic duct/liver, and common bile duct/liver were measured using the ImageJ software (National Institutes of Health, Bethesda, USA). Visibility of the gallbladder and bile ducts was classified into three categories (grades A, B, and C) based on the degree of visibility in contrast to the liver.

RESULTS

The luminance intensity ratio for the gallbladder/liver, cystic duct/liver, and common bile duct/liver was ≥1 in the 15-, 18-, and 24-h groups. The proportion of cases in which evaluators classified the visibility of the gallbladder and bile ducts as grade A (best visibility) reached a peak in the 15-h group and decreased thereafter.

CONCLUSIONS

In the present study, the optimal timing of indocyanine green administration for fluorescent cholangiography during laparoscopic cholecystectomy using the PINPOINT Endoscopic Fluorescence Imaging System was 15 h before surgery.

Photodynamic diagnosis of peritoneal metastasis in human pancreatic cancer using 5-aminolevulinic acid during staging laparoscopy

Peritoneal metastasis is an important prognostic factor for pancreatic cancer. The present study evaluated the possibility of diagnosing peritoneal metastasis by a photodynamic diagnosis using 5-aminolevulinic acid (5-ALA-PDD). In vitro, protoporphyrin IX (PpIX) accumulation was examined in the AsPC-1-GFP cell line following 5-ALA hydrochloride administration. In vivo, AsPC-1-GFP cells were injected into the peritoneal cavities of mice. Three weeks later 5-ALA hydrochloride was intraperitoneally administered to the mice. The peritoneal nodules were observed under fluorescence excitation. A total of 34 patients were enrolled in the present study who were clinically diagnosed with pancreatic malignancy. 5-ALA hydrochloride was orally administered to the patients prior to surgery. During the operation the abdominal cavity was observed under white light and fluorescence. In vitro and in vivo, it was confirmed that PpIX-induced red fluorescence. In 9 patients peritoneal nodules suspected to be peritoneal metastasis were observed under white light. In 4 of the 9 patients nodules were detected on the basis of the fluorescence images. Fluorescent nodules were histopathologically diagnosed as metastatic. In the present study it was confirmed that 5-ALA-PDD holds promise for the rapid diagnosis of peritoneal metastasis in patients with pancreatic cancer.

A next-generation bifunctional photosensitizer with improved water-solubility for photodynamic therapy and diagnosis

Photodynamic therapy (PDT) exploits light interactions and photosensitizers to induce cytotoxic reactive oxygen species. Photodynamic diagnosis (PDD) uses the phenomenon of photosensitizer emitting fluorescence to distinguish some tumors from normal tissue. The standard photosensitizer used for PDD is 5-aminolevulinic acid (5-ALA), although it is not entirely satisfactory. We previously reported glucose-conjugated chlorin (G-chlorin) as a more effective photosensitizer than another widely used photosensitizer, talaporfin sodium (TS); however, G-chlorin is hydrophobic. We synthesized oligosaccharide-conjugated chlorin (O-chlorin) with improved water-solubility. We report herein on its accumulation and cytotoxicity. O-chlorin was synthesized and examined for solubility. Flow cytometric analysis was performed to evaluate O-chlorin accumulation in cancer cells. To evaluate the intracellular localization of photosensitizer, cells were stained with O-chlorin and organelle-specific fluorescent probes. We then measured the in vitro fluorescence of various photosensitizers and the half-maximal inhibitory concentrations to evaluate effects in PDD and PDT, respectively. Xenograft tumor models were established, and antitumor and visibility effects were analyzed. O-chlorin was first shown to be hydrophilic. Flow cytometry then revealed a 20- to 40-times higher accumulation of O-chlorin in cancer cells than of TS, and a 7- to 23-times greater fluorescence than 5-ALA. In vitro, the cytotoxicity of O-chlorin PDT was stronger than that of TS PDT, and O-chlorin tended to accumulate in lysosomes. In vivo, O-chlorin showed the best effect in PDT and PDD compared to other photosensitizers.

O-chlorin was hydrophilic and showed excellent tumor accumulation and fluorescence. O-chlorin is promising as a next-generation bifunctional photosensitizer candidate for both PDT and PDD.

Precise integrin-targeting near-infrared imaging-guided surgical method increases surgical qualification of peritoneal carcinomatosis from gastric cancer in mice

Peritoneal carcinomatosis from gastric cancer represents a common recurrent gastric cancer that seriously affects the survival, prognosis, and quality of life of patients at its advanced stage. In recent years, complete cytoreduction surgery in combination with hyperthermic intraperitoneal chemotherapy has been demonstrated to improve the survival and prognosis of patients with malignant tumors including peritoneal carcinomatosis from gastric cancer. Establishing viable methods of accurately assessing the tumor burden in patients with peritoneal carcinoma and correctly selecting suitable patients in order to improve cytoreduction surgical outcomes and reduce the risk of postoperative complications has become a challenge in the field of peritoneal carcinoma research. Here, we investigated peritoneal carcinomatosis from gastric cancer in a mouse model by using our self-developed surgical navigation system that combines optical molecular imaging with an integrin-targeting Arg-Gly-Asp-indocyanine green (RGD-ICG) molecular probe. The results showed that our diagnostic method could achieve a sensitivity and specificity of up to 93.93% and 100%, respectively, with a diagnostic index (DI) of 193.93% and diagnostic accuracy rate of 93.93%.Furthermore, the minimum tumor diameter measured during the surgery was 1.8 mm and the operative time was shortened by 3.26-fold when compared with the conventionally-treated control group. Therefore, our surgical navigation system that combines optical molecular imaging with an RGD-ICG molecular probe, could improve the diagnostic accuracy rate for peritoneal carcinomatosis from gastric cancer, shorten the operative time, and improve the quality of the cytoreduction surgery for peritoneal carcinomatosis from gastric cancer, thus providing a solid foundation for its future clinical development and application.

Protoporphyrinogen oxidase is involved in the fluorescence intensity of 5-aminolevulinic acid-mediated laser-based photodynamic endoscopic diagnosis for early gastric cancer

BACKGROUND/AIM

Laser-based photodynamic endoscopic diagnosis (LPDED) is a type of endoscopic diagnosis that uses the fluorescence caused by the photochemical reaction that occurs when a fluorescent substance is irradiated by a light of a specific wavelength. Although 5-aminolevulinic acid (5-ALA) can detect early gastric cancer (EGC) during LPDED, there is an unresolved issue of the differences in fluorescence intensity among histopathological types of gastric cancer. Thus, the aim of the present study was to assess whether protoporphyrinogen oxidase (PPOX), involved in the activation of protoporphyrin IX, can affect the fluorescence intensity in EGC.

METHODS

Thirty-three gastric tumor lesions in 30 patients were assessed by LPDED using a prototype endoscope equipped with a blue laser ray to cause excitation following oral 5-ALA administration. The tumors were then resected by endoscopic submucosal dissection or laparoscopic surgery. PPOX expression was examined immunohistochemically in the excised specimens. To explore the mechanisms of histopathological diversity in PPOX and coproporphyrinogen oxidase (CPOX) expression of EGC, immunohistochemical analysis was performed using 75 surgically resected specimens of diverse EGCs.

RESULTS

Among the 33 lesions, 26 tumors were detectable by LPDED, whereas seven were undetectable. Between the LPDED-positive and negative groups, there was a significant difference in histopathology. The expression of PPOX was higher in tubular adenocarcinoma (tub) than in signet-ring cell carcinoma (sig). There were significant differences in PPOX and CPOX expression scores of the surgically resected specimens among tub, poorly differentiated adenocarcinoma (por), and sig.

CONCLUSION

PPOX protein expression could be involved in the fluorescence intensity of LPDED in EGC, possibly reflecting histopathological features.

Fluorescence-guided surgery for cancer patients: a proof of concept study on human xenografts in mice and spontaneous tumors in pets

Surgery is often the first treatment option for patients with cancer. Patient survival essentially depends on the completeness of tumor resection. This is a major challenge, particularly in cases of peritoneal carcinomatosis, where tumors are widely disseminated in the large peritoneal cavity. Any development to help surgeons visualize these residual cells would improve the completeness of the surgery. For non-disseminated tumors, imaging could be used to ensure that the tumor margins and the draining lymph nodes are free of tumor deposits.

Near-infrared fluorescence imaging has been shown to be one of the most convenient imaging modalities. Our aim was to evaluate the efficacy of a near-infrared fluorescent probe targeting the αvβ3 integrins (Angiostamp™) for intraoperative detection of tumors using the Fluobeam® device.

We determined whether different human tumor nodules from various origins could be detected in xenograft mouse models using both cancer cell lines and patient-derived tumor cells. We found that xenografts could be imaged by fluorescent staining irrespective of their integrin expression levels. This suggests imaging of the associated angiogenesis of the tumor and a broader potential utilization of Angiostamp™. We therefore performed a veterinary clinical trial in cats and dogs with local tumors or with spontaneous disseminated peritoneal carcinomatosis. Our results demonstrate that the probe can specifically visualize both breast and ovarian nodules, and suggest that Angiostamp™ is a powerful fluorescent contrast agent that could be used in both human and veterinary clinical trials for intraoperative detection of tumors.

Novel potential photodynamic therapy strategy using 5-Aminolevulinic acid for ovarian clear-cell carcinoma

BACKGROUND

Photodynamic therapy (PDT) is known as a minimally invasive treatment for cancer. 5-Aminolevulinic acid (ALA) is a precursor of the photosensitizing agent protoporphyrin IX (PpIX). Patients with ovarian clear-cell carcinoma (CCC) have poorer prognoses than those of patients with other histological CCC types. We evaluated the efficacy of ALA-PDT on CCC cells in vitro.

METHODS

We used seven human CCC cell lines to measure the cytotoxicity of ALA-PDT. PpIX production in cancer cells was measured using a micro-plate reader. Quantitative real-time PCR was performed to assess the mRNA levels of genes involved in the accumulation of PpIX in cancer cells. Additionally, we measured the enhancement in cytotoxicity with the use of an ABCG2 inhibitor.

RESULTS

We found that three cell lines were highly sensitive to ALA-PDT. In contrast, one cell line was resistant to ALA-PDT. The cytotoxicity of ALA-PDT varied among CCC cell lines. The IC50 values of ALA-PDT for the CCC cell lines had a wide range (30-882μM). The cytotoxicity of ALA-PDT was correlated with the intracellular PpIX accumulation. The cell lines sensitive to ALA-PDT expressed PEPT1 (an ALA uptake transporter). The cell line resistant to ALA-PDT expressed ABCG2 (a PpIX export transporter). In the resistant cell line, a combination treatment with both ALA and an ABCG2 inhibitor resulted in the promotion of cytotoxic sensitivity.

CONCLUSION

The present study revealed the efficacy of ALA-PDT against CCC with chemoresistance in vitro.

Towards dosimetry for photodynamic diagnosis with the low-level dose of photosensitizer

BACKGROUND

Contemporary medicine does not concern the issue of dosimetry in photodynamic diagnosis (PDD) but follows the photosensitizer (PS) producers recommendation. Most preclinical and clinical PDD studies indicate a considerable variation in the possibility of visualization and treatment, as e.g. in case of cervix lesions. Although some of these variations can be caused by the different histological subtypes or various tumor geometries, the issue of varying PS concentration in the tumor tissue volume is definitely an important factor. Therefore, there is a need to establish the objective and systematic PDD dosimetry protocol regarding doses of light and photosensitizers.

METHODS

Four different irradiation sources investigated in PDD (literature) were used for PS excitation. The PS luminescence was examined by means of the non-imaging (spectroscopic) and imaging (wide- and narrow-field of view) techniques. The methodology for low-level intensity photoluminescence (PL) characterization and dedicated image processing algorithm for PS luminescence images analysis were proposed. Further, HeLa cells' cultures penetration by PS was studied by a confocal microscopy.

RESULTS

Reducing the PS dose with the choice of proper photoexcitation conditions decreases the PDD procedure costs and the side effects, not affecting the diagnostic efficiency. We determined in vitro the minimum incubation time and photosensitizer concentration of Photolon for diagnostic purposes, for which the Photolon PL can still be observed. It was demonstrated that quantification of PS concentration, choice of proper photoexcitation source, appropriate adjustment of light dose and PS penetration of cancer cells may improve the low-level luminescence photodynamic diagnostics performance.

CONCLUSIONS

Practical effectiveness of the PDD strongly depends on irradiation source parameters (bandwidth, maximum intensity, half-width) and their optimization is the main conditioning factor for low-level intensity and low-cost PDD.

Stable archaeal tetraether lipid liposomes for photodynamic application: transfer of carboxyfluorescein to cultured T84 tumor cells

Background: Archaeal membranes have phytanyl ether lipids instead of common fatty acid-glycerol esters in bacterial and eukaryotic cells. Sulfolobus and Thermoplasma species have unique membrane-spanning tetraether lipids (TEL), which form stable liposomes. Recently, we cultured Thermoplasma species from the Indonesian volcano Tangkuban Perahu and isolated TEL. The purpose of this in vitro study is to investigate the transfer of fluorescent dye from stable TEL liposomes to cultured colon carcinoma cells.Methods: TEL was extracted from cultured cells with chloroform-methanol (1:1), then it was fractionated and purified via diethylaminoethyl-cellulose-acetate columns and activated charcoal for the formation of stable liposomes. For the fluorescence exchange assay, TEL liposomes were loaded with water-soluble carboxyfluorescein (CF). Staining experiments were conducted with various cell cultures, and T84 colon carcinoma cells were chosen for the main experiments. Liposome stability was tested by light scattering and electron microscopic size determinations as well as by unspecific CF release at low pH (6.0–7.4) and increased temperature  (4–50°C/70°C).Results: TEL liposomes exhibit high stability and extremely low proton permeability at low pH. CF staining of cultured T84 colon carcinoma cells appeares more intensive from TEL liposomes than from dipalmitoylphosphatidylcholine liposomes.Conclusion: The results of this in vitro study demonstrate CF staining of colon carcinoma cells and high stability of TEL liposomes at low pH, matching the condition in the gastro-intestinal (GI) route and in the urogentital (UG) tract. For this reason, in vivo studies on liposomal fluorescent photosensitizers for topical application of photodynamic cancer therapy in the GI and UG tracts should be carried out.

The impact of electrode resistance on the biogalvanic characterisation technique

Measurement of a tissue-specific electrical resistance may offer a discriminatory metric for evaluation of tissue health during cancer surgery. With a move toward minimally-invasive procedures, applicable contact sensing modalities must be scalable, fast and robust. A passive resistance characterisation method utilising a biogalvanic cell as an intrinsic power source has been proposed as a potentially suitable solution. Previous work has evaluated this system with results showing effective discrimination of tissue type and damage (through electroporation). However, aspects of the biogalvanic cell have been found to influence the characterisation performance, and are not currently accounted for within the system model. In particular, the electrode and salt-bridge resistance are not independently determined, leading to over-predictions of tissue resistivity.

This paper describes a more comprehensive model and characterisation scheme, with electrode parameters and salt-bridge resistivity being evaluated independently. In a generalised form, the presented model illustrates how the relative resistive contributions from the electrodes and medium relate to the existing characterisation method efficacy. We also describe experiments with physiologically relevant salt solutions (1.71, 17.1, 154 mM), used for validation and comparison. The presented model shows improved performance over the current biogalvanic measurement technique at the median conductivity. Both the proposed and extant system models become unable to predict conductivity accurately at high conductivity due to the dominance of the electrodes. The characterisation techniques have also been applied to data collected on freshly excised human colon tissue (healthy and cancerous). The findings suggest that the resistance of the cell under the test conditions is electrode dominated, leading to erroneous tissue resistance determination. Measurement optimisation strategies and the surgical applicability of the biogalvanic technique are discussed in light of these findings.

Biliary tract visualization using near-infrared imaging with indocyanine green during laparoscopic cholecystectomy: results of a systematic review

Background

Near-infrared imaging with indocyanine green (ICG) has been extensively investigated during laparoscopic cholecystectomy (LC). However, methods vary between studies, especially regarding patient selection, dosage and timing. The aim of this systematic review was to evaluate the potential of the near-infrared imaging technique with ICG to identify biliary structures during LC.

Methods

A comprehensive systematic literature search was performed. Prospective trials examining the use of ICG during LC were included. Primary outcome was biliary tract visualization. Risk of bias was assessed using ROBINS-I. Secondly, a meta-analysis was performed comparing ICG to intraoperative cholangiography (IOC) for identification of biliary structures. GRADE was used to assess the quality of the evidence.

Results

Nineteen studies were included. Based upon the pooled data from 13 studies, cystic duct (Lusch et al. in J Endourol 28:261–266, 2014) visualization was 86.5% (95% CI 71.2–96.6%) prior to dissection of Calot’s triangle with a 2.5-mg dosage of ICG and 96.5% (95% CI 93.9–98.4%) after dissection. The results were not appreciably different when the dosage was based upon bodyweight. There is moderate quality evidence that the CD is more frequently visualized using ICG than IOC (RR 1.16; 95% CI 1.00–1.35); however, this difference was not statistically significant.

Conclusion

This systematic review provides equal results for biliary tract visualization with near-infrared imaging with ICG during LC compared to IOC. Near-infrared imaging with ICG has the potential to replace IOC for biliary mapping. However, methods of near-infrared imaging with ICG vary. Future research is necessary for optimization and standardization of the near-infrared ICG technique.

Electronic supplementary material

The online version of this article (doi:10.1007/s00464-016-5318-7) contains supplementary material, which is available to authorized users.

Rapid Cancer Fluorescence Imaging Using A γ-Glutamyltranspeptidase-Specific Probe For Primary Lung Cancer

BACKGROUND: We set out to examine the activity of γ-glutamyltranspeptidase (GGT) in lung cancer and the validity of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) for intraoperative imaging of primary lung cancer. METHODS: GGT activities and mRNA expression levels of GGT1 (one of the GGT subtypes) in five human lung cancer cell lines were examined by fluorescence imaging and quantitative reverse transcription polymerase chain reaction. In vivo imaging of an orthotopic A549 xenograft model in nude mice was performed to confirm its applicability to intraoperative imaging. Furthermore, ex vivo imaging of 73 specimens from lung cancer patients were performed and analyzed to calculate the sensitivity/specificity of gGlu-HMRG for lung cancer diagnosis. RESULTS: GGT activities and mRNA expression levels of GGT1 are diverse depending on cell type; A549, H441, and H460 showed relatively high GGT activities and expression levels, whereas H82 and H226 showed lower values. In the in vivo mouse model study, tiny pleural dissemination and hilar/mediastinal lymph node metastasis (less than 1 mm in diameter) were clearly detected 15 minutes after topical application of gGlu-HMRG. In the ex vivo study of specimens from patients, the sensitivity and specificity of gGlu-HMRG were calculated to be 43.8% (32/73) and 84.9% (62/73), respectively. When limited to female patients, never smokers, and adenocarcinomas, these values were 78.9% (15/19) and 73.7% (14/19), respectively. CONCLUSIONS: Although GGT activity of lung cancer cells vary, gGlu-HMRG can serve as an intraoperative imaging tool to detect small foci of lung cancer when such cells have sufficient GGT activity.

Simplified and optimized multispectral imaging for 5-ALA-based fluorescence diagnosis of malignant lesions

5-aminolevulinic acid (5-ALA)-based fluorescence diagnosis is now clinically applied for accurate and ultrarapid diagnosis of malignant lesions such as lymph node metastasis during surgery. 5-ALA-based diagnosis evaluates fluorescence intensity of a fluorescent metabolite of 5-ALA, protoporphyrin IX (PPIX); however, the fluorescence of PPIX is often affected by autofluorescence of tissue chromophores, such as collagen and flavins. In this study, we demonstrated PPIX fluorescence estimation with autofluorescence elimination for 5-ALA-based fluorescence diagnosis of malignant lesions by simplified and optimized multispectral imaging. We computationally optimized observation wavelength regions for the estimation of PPIX fluorescence in terms of minimizing prediction error of PPIX fluorescence intensity in the presence of typical chromophores, collagen and flavins. By using the fluorescence intensities of the optimized wavelength regions, we verified quantitative detection of PPIX fluorescence by using chemical mixtures of PPIX, flavins, and collagen. Furthermore, we demonstrated detection capability by using metastatic and non-metastatic lymph nodes of colorectal cancer patients. These results suggest the potential and usefulness of the background-free estimation method of PPIX fluorescence for 5-ALA-based fluorescence diagnosis of malignant lesions, and we expect this method to be beneficial for intraoperative and rapid cancer diagnosis.

Animal models of colorectal peritoneal metastasis

Colorectal cancer remains an important cause of mortality worldwide. The presence of peritoneal carcinomatosis (PC) causes significant symptoms and is notoriously difficult to treat. Therefore, informative preclinical research into the mechanisms and possible novel treatment options of colorectal PC is essential in order to improve the prognostic outlook in these patients. Several syngeneic and xenograft animal models of colorectal PC were established, studying a wide range of experimental procedures and substances. Regrettably, more sophisticated models such as those giving rise to spontaneous PC or involving genetically engineered mice are lacking. Here, we provide an overview of all reported colorectal PC animal models and briefly discuss their use, strengths, and limitations.

Highly sensitive fluorescence detection of metastatic lymph nodes of gastric cancer with photo-oxidation of protoporphyrin IX

BACKGROUND

The establishment of a precise and rapid method to detect metastatic lymph nodes (LNs) is essential to perform less invasive surgery with reduced gastrectomy along with reduced lymph node dissection. We herein describe a novel imaging strategy to detect 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence in excised LNs specifically with reduced effects of tissue autofluorescence based on photo-oxidation of PpIX. We applied the method in a clinical setting, and evaluated its feasibility.

METHODS

To reduce the unfavorable effect of autofluorescence, we focused on photo-oxidation of PpIX: Following light irradiation, PpIX changes into another substance, photo-protoporphyrin, via an oxidative process, which has a different spectral peak, at 675 nm, whereas PpIX has its spectral peak at 635 nm. Based on the unique spectral alteration, fluorescence spectral imaging before and after light irradiation and subsequent originally-developed image processing was performed. Following in vitro study, we applied this method to a total of 662 excised LNs obtained from 30 gastric cancer patients administered 5-ALA preoperatively.

RESULTS

Specific visualization of PpIX was achieved in in vitro study. The method allowed highly sensitive detection of metastatic LNs, with sensitivity of 91.9% and specificity of 90.8% in the in vivo clinical trial. Receiver operating characteristic analysis indicated high diagnostic accuracy, with the area under the curve of 0.926.

CONCLUSIONS

We established a highly sensitive and specific 5-ALA-induced fluorescence imaging method applicable in clinical settings. The novel method has a potential to become a useful tool for intraoperative rapid diagnosis of LN metastasis.

Recent advances in photodynamic diagnosis of gastric cancer using 5-aminolevulinic acid

Photodynamic diagnosis based on 5-aminolevulinic acid-induced protoporphyrin IX has been clinically applied in many fields based upon its evidenced efficacy and adequate safety. In order to establish a personalized medicine approach for treating gastric cancer patients, rapid intraoperative detection of malignant lesions has become important. Feasibility of photodynamic diagnosis using 5-aminolevulinic acid for gastric cancer patients has been investigated, especially for the detection of peritoneal dissemination and lymph node metastasis. This method enables intraoperative real-time fluorescence detection of peritoneal dissemination, exhibiting higher sensitivity than white light observation without histopathological examination. The method also enables detection of metastatic foci within excised lymph nodes, exhibiting a diagnostic accuracy comparable to that of a current molecular diagnostics technique. Although several complicating issues still need to be resolved, such as the effect of tissue autofluorescence and the insufficient depth penetration of excitation light, this simple and rapid method has the potential to become a useful diagnostic tool for gastric cancer, as well as urinary bladder cancer and glioma.

A novel multiple electrode direct current technique for characterisation of tissue resistance during surgery

Electrochemical and electrical characteristics have the potential to help differentiate between, and assess the health state of, different biological tissues. However, measurement and interpretation of these characteristics is non-trivial. We propose a new DC galvanostatic sensing method for application to laparoscopic cancer surgery. This presents a simple and cost-effective measurement coupled with straightforward data interpretation. This paper describes the electrochemical and electrical theory underpinning the technique. Additionally, we describe a measurement system employing this technique and present an investigation into the feasibility of using it for measuring the resistance of different tissue types. Measurements were performed on ex vivo porcine liver, colon and rectum tissues. Outputs were consistent with theory and showed a significant difference between the resistance of the different tissue types, (one-way ANOVA, F(2, 28) = 1369, p <; 0.01). These findings indicate that this novel technique may be viable as a low cost method for the discrimination and health assessment of tissues in clinical scenarios.

Engineering Corynebacterium glutamicum to produce 5-aminolevulinic acid from glucose

BACKGROUND

Corynebacterium glutamicum is generally regarded as a safe microorganism and is used to produce many biochemicals, including L-glutamate. 5-Aminolevulinic acid (ALA) is an L-glutamate derived non-protein amino acid, and is widely applied in fields such as medicine and agriculture.

RESULTS

The products of the gltX, hemA, and hemL genes participate in the synthesis of ALA from L-glutamate. Their annotated C. glutamicum homologs were shown to be functional using heterologous complementation and overexpression techniques. Coexpression of hemA and hemL in native host led to the accumulation of ALA, suggesting the potential of C. glutamicum to produce ALA for research and commercial purposes. To improve ALA production, we constructed recombinant C. glutamicum strains expressing hemA and hemL derived from different organisms. Transcriptome analysis indicated that the dissolved oxygen level and Fe(2+) concentration had major effects on ALA synthesis. The downstream pathway of heme biosynthesis was inhibited using small molecules or introducing genetic modifications. Small-scale flask cultures of engineered C. glutamicum produced 1.79 g/L of ALA.

CONCLUSION

Functional characterization of the key enzymes indicated complex regulation of the heme biosynthetic pathway in C. glutamicum. Systematic analysis and molecular genetic engineering of C. glutamicum may facilitate its development as a system for large-scale synthesis of ALA.

Enhanced Reality and Intraoperative Imaging in Colorectal Surgery

Colorectal surgery is one of the most common procedures performed around the world with more than 600,000 operations each year in the United States, and more than a million worldwide. In the past two decades, there has been a clear trend toward minimal access and surgeons have embraced this evolution. Widespread adoption of advanced minimally invasive procedures is often limited by procedural complexity and the need for specific technical skills. Furthermore, the loss of 3D vision, limited overview of the surgical field, and diminished tactile sensation make major colorectal procedures more challenging and have an impact on the surgeons' learning curves. New technologies are emerging that can compensate for some of the sensory losses associated with laparoscopy. High-definition picture acquisition, 3D camera systems, and the use of biomarkers will allow improved identification of the target structures and help differentiate them from surrounding tissues. In this article, we describe some of the new technologies available and, in particular, focus on the possible implications of biomarkers and fluorescent laparoscopic imaging.

Incidence and treatment of recurrent disease after cytoreductive surgery and intraperitoneal chemotherapy for peritoneally metastasized colorectal cancer: A systematic review

INTRODUCTION

The optimal treatment for peritoneal carcinomatosis (PC) of colorectal origin is a combination of cytoreductive surgery and intraperitoneal chemotherapy (CRS + IPC). Although 5-year survival rates of up to 40% have been reported, recurrent disease remains common and is estimated to be a strong negative prognostic factor for survival. This systematic review elaborates on the incidence of recurrent disease and the possibilities to prevent and treat recurrence.

METHODS

Two searches were performed. To identify the magnitude of recurrent the disease, a search was performed in Pubmed and EMBASE until September 2014. A second search was performed in Pubmed to identify treatment of recurrent disease with secondary CRS + IPC.

RESULTS

The first search resulted in 139 and 94 articles in Pubmed and EMBASE respectively. Among those, 28 were included. Overall recurrence rates ranged from 22.5 to 82%. Local, systemic and combined local-systemic recurrence ranged from 6 to 42.5%, 10.4-43% and 5.8-21.5%. Median time to recurrence varied from 9 to 23 months, three-year disease free survival ranged from 14 to 41.5%. The second search resulted in 140 articles among which 17 met the inclusion criteria. A total of 190 patients underwent secondary CRS. Median survival after the second procedure ranged from 18 to 55.7 months. One, two and three-year survival ranged between 66 and 94, 44-50 and 0-66%.

CONCLUSION

Recurrence is very common after cytoreductive surgery and intraperitoneal chemotherapy for PC of colorectal origin. Repeat cytoreductive surgery suggests a potential survival benefit for a highly selected group. Therefore, strategies to prevent recurrence are of the utmost importance.

Plasma protoporphyrin IX following administration of 5-aminolevulinic acid as a potential tumor marker

Exogenously administered 5-aminolevulinic acid (ALA) is metabolized to protoporphyrin IX (PpIX), which specifically accumulates in cancer cells and emits red fluorescence by blue light irradiation. These phenomena are applied for the intraoperative diagnosis of cancer. Based on the fact that accumulated PpIX in cancer cells is exported extracellularly via the ATP-binding cassette transporter G2, we hypothesized that the measurement of plasma PpIX concentrations could be applied as a tumor marker for cancer screening. In the present study, the use of plasma samples from bladder cancer patients were evaluated as a tumor marker. ALA, 1.0 g, was orally administered to bladder cancer patients and healthy adults. The plasma concentration of PpIX was measured using a high-performance liquid chromatography system. The plasma PpIX concentration following ALA administration was significantly higher in bladder cancer patients than that in the healthy adults, suggesting the effectiveness of plasma PpIX analysis following ALA administration for cancer screening. Additionally, 4 h after ALA administration, plasma PpIX showed high sensitivity (94.4%) and high specificity (80.0%).

Photodynamic diagnosis for detection of peritoneal carcinomatosis

BACKGROUND

Peritoneal carcinomatosis is the dissemination of cancer in the peritoneal cavity secondary to abdominal or extra-abdominal malignancies. Accurate assessment of the disease's burden is a challenge because of the complexity of the peritoneal cavity and the small size of the metastatic nodules. Photodynamic diagnosis (PDD) is an emerging technology in tumor diagnosis. A photosensitizer is administered, which is preferentially taken up by cancer cells. The photosensitizer emits fluorescence when exposed to a light of a specific wavelength. This helps distinguish cancer from normal tissues.

METHODS

We systematically reviewed the evidence for using PDD in detecting peritoneal carcinomatosis in both animal and human literature. Both Medline and EMBASE databases were searched (November 2014). The titles and the abstracts of all retrieved citations were inspected, and the full articles of the relevant articles were obtained.

RESULTS

A total of 12 human and 18 animal studies were included. Clinical studies have shown PDD to be a safe modality with no significant adverse effects. It increases the detection of malignant peritoneal nodules by 21%-34% in comparison with white light alone. The sensitivity and specificity of PDD were reported at 83%-100% and 95%-100%, respectively. These findings were supported by multiple animal studies, which have shown an increase in the sensitivity of tumor detection when using PDD (72%-91%) in comparison with white light alone (39%).

CONCLUSIONS

PDD is a promising modality, which improves the detection of peritoneal carcinomatosis lesions. Further research, however, should investigate the impact of PDD on the patients' therapeutic management and final outcomes.

Sulforaphane attenuates homocysteine-induced endoplasmic reticulum stress through Nrf-2-driven enzymes in immortalized human hepatocytes

In the present study, we investigated the potential efficacy of cruciferous vegetable-derived sulforaphane (SFN) in improving homocysteine (HCY)-stressed cells. After human hepatocyte line HHL-5 was preincubated with SFN and subsequently with 10 mmol/L HCY, SFN improved the pathologic changes which are caused by HCY, including cell morphological abnormality, endoplasmic reticulum (ER) swelling, excessive generation of reactive oxygen species (ROS), the increased malondialdehyde (MDA) levels, as well as the increased activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Phase II enzymes, thioredoxin reductase-1 (TrxR-1) and

NAD(P)H

quinone oxidoreductase 1 (NQO1), were involved in the protective effect of SFN against injury by HCY. The ER stress-specific proteins, such as glucose-regulated protein-78 (GRP78) and protein kinase RNA (PKR)-like ER kinase (PERK), were strikingly abolished by SFN. Furthermore, Nrf-2 translocation was enhanced by SFN, which lead to the induction of TrxR-1and NQO1.