Respiratory and locomotor muscle blood flow measurements using near-infrared spectroscopy and indocyanine green dye in health and disease.

Measuring respiratory and locomotor muscle blood flow during exercise is pivotal for understanding the factors limiting exercise tolerance in health and disease. Traditional methods to measure muscle blood flow present limitations for exercise testing. This article reviews a method utilising near-infrared spectroscopy (NIRS) in combination with the light-absorbing tracer indocyanine green dye (ICG) to simultaneously assess respiratory and locomotor muscle blood flow during exercise in health and disease. NIRS provides high spatiotemporal resolution and can detect chromophore concentrations. Intravenously administered ICG binds to albumin and undergoes rapid metabolism, making it suitable for repeated measurements. NIRS-ICG allows calculation of local muscle blood flow based on the rate of ICG accumulation in the muscle over time. Studies presented in this review provide evidence of the technical and clinical validity of the NIRS-ICG method in quantifying respiratory and locomotor muscle blood flow. Over the past decade, use of this method during exercise has provided insights into respiratory and locomotor muscle blood flow competition theory and the effect of ergogenic aids and pharmacological agents on local muscle blood flow distribution in COPD. Originally, arterial blood sampling was required via a photodensitometer, though the method has subsequently been adapted to provide a local muscle blood flow index using venous cannulation. In summary, the significance of the NIRS-ICG method is that it provides a minimally invasive tool to simultaneously assess respiratory and locomotor muscle blood flow at rest and during exercise in health and disease to better appreciate the impact of ergogenic aids or pharmacological treatments.

Assessment of liver function-related mRNA expression and fluorescence imaging in outflow-obstructed regions in rats.

PURPOSE: The liver function in outflow-obstructed regions is reportedly impaired; however, the functional decrease has not been quantitatively assessed. We therefore evaluated the uptake of indocyanine green (ICG) into hepatocytes and the mRNA expression associated with the liver function in outflow-obstructed regions using rat models. METHODS: A total of 20 rats with the ligation of the right median hepatic vein to induce outflow obstruction were studied. Five rats each were grouped by the time of re-laparotomy, and the fluorescence intensity (FI) values of ICG. The mRNA expression, including that of Albumin, Cytochrome P450 (Cyp) 1a2, Cyp3a1, Cyp7a1, and Gamma-glutamylcysteine synthetase, in outflow-obstructed (mRNAOut-Ob) and non-outflow-obstructed (mRNANon) regions was assessed. RESULTS: Microscopic fluorescence imaging showed that the FI values were significantly lower in outflow-obstructed regions than in non-outflow-obstructed regions at 12 h, 24 h, and 3 days after ligation of the hepatic vein. The mRNAOut-Ob/mRNANon ratios decreased to approximately 30% at 12 h after the outflow obstruction and increased to approximately 70-80% at 7 days. CONCLUSIONS: The liver function in outflow-obstructed regions was impaired in terms of the uptake of ICG and the mRNA expression. Our findings may help estimate the postoperative functional remnant liver volume by considering the decrease in the liver function in outflow-obstructed regions.

Repair of the Urethral Mucosa Defect Model Using Adipose-Derived Stem Cell Sheets and Monitoring the Fate of Indocyanine Green-Labeled Sheets by Near Infrared-II.

Treatment of urethral mucosa defects is a major challenge in urology. Synthetic materials or autologous mucosa does not provide satisfactory treatment options for long-term or large urethral mucosa defects. In response to this problem, we used autologous adipose-derived stem cells (ADSCs) to synthesize cell sheets in vitro for repairing urethral mucosa defect models. In order to monitor the localization and distribution of cell sheets in vivo, cells and sheets were labeled with indocyanine green (ICG) and the second near-infrared (NIR-II) fluorescence imaging was performed. ICG-based NIR-II imaging can successfully track ADSCs and sheets in vivo up to 8 W. Then, rabbit urethral mucosa defect models were repaired with ICG-ADSCs sheets. At 3 months after operation, retrograde urethrography showed that ADSC sheets could effectively repair urethral mucosa defect and restore urethral patency. Histological analysis showed that in ADSC sheet groups, continuous epithelial cells covered the urethra at the transplantation site, and a large number of vascular endothelial cells could also be seen. In the cell-free sheet group, there was no continuous epithelial cell coverage at the repair site of the urethra, and the expression of pro-inflammatory factor TNF-α was increased. It shows that the extracellular matrix alone without cells is not suitable for repairing urethral defects. Surviving ADSCs in the sheets may play a key role in the repair process. This study provides a new tracing method for tissue engineering to dynamically track grafts using an NIR-II imaging system. The ADSC sheets can effectively restore the structure and function of the urethra. It provides a new option for the repair of urethral mucosa defects.

Direct Differentiation of Human Embryonic Stem Cells to 3D Functional Hepatocyte-like Cells in Alginate Microencapsulation Sphere.

BACKGROUND: The lack of a stable source of hepatocytes is one of major limitations in hepatocyte transplantation and clinical applications of a bioartificial liver. Human embryonic stem cells (hESCs) with a high degree of self-renewal and totipotency are a potentially limitless source of a variety of cell lineages, including hepatocytes. Many techniques have been developed for effective differentiation of hESCs into functional hepatocyte-like cells. However, the application of hESC-derived hepatocyte-like cells (hESC-Heps) in the clinic has been constrained by the low yield of fully differentiated cells, small-scale culture, difficulties in harvesting, and immunologic graft rejection. To resolve these shortcomings, we developed a novel 3D differentiation system involving alginate-microencapsulated spheres to improve current hepatic differentiation, providing ready-to-use hESC-Heps. METHODS: In this study, we used alginate microencapsulation technology to differentiate human embryonic stem cells into hepatocyte-like cells (hESC-Heps). Hepatic markers of hESC-Heps were examined by qPCR and Western blotting, and hepatic functions of hESC-Heps were evaluated by indocyanine-green uptake and release, and ammonia removal. RESULTS: The maturity and hepatic functions of the hESC-Heps derived from this 3D system were better than those derived from 2D culture. Hepatocyte-enriched genes, such as HNF4α, AFP, and ALB, were expressed at higher levels in 3D hESC-Heps than in 2D hESC-Heps. 3D hESC-Heps could metabolize indocyanine green and had better capacity to scavenge ammonia. In addition, the 3D sodium alginate hydrogel microspheres could block viral entry into the microspheres, and thus protect hESC-Heps in 3D microspheres from viral infection. CONCLUSION: We developed a novel 3D differentiation system for differentiating hESCs into hepatocyte-like cells by using alginate microcapsules.

Sterically Shielded Hydrophilic Analogs of Indocyanine Green.

A modular synthetic process enables two or four shielding arms to be appended strategically over the fluorochromes of near-infrared cyanine heptamethine dyes to create hydrophilic analogs of clinically approved indocyanine green. A key synthetic step is the facile substitution of a heptamethine 4'-Cl atom by a phenol bearing two triethylene glycol chains. The lead compound is a heptamethine dye with four shielding arms, and a series of comparative spectroscopy studies showed that the shielding arms (a) increased dye photostability and chemical stability and (b) inhibited dye self-aggregation and association with albumin protein. In mice, the dye cleared from the blood primarily through the renal pathway rather than the biliary pathway for ICG. This change in biodistribution reflects the much smaller hydrodynamic diameter of the shielded hydrophilic ICG analog compared to the 67 kDa size of the ICG/albumin complex. An attractive feature of versatile synthetic chemistry is the capability to systematically alter the dye's hydrodynamic diameter. The sterically shielded hydrophilic ICG dye platform is well-suited for immediate incorporation into dynamic contrast-enhanced (DCE) spectroscopy or imaging protocols using the same cameras and detectors that have been optimized for ICG.

Triazole-derivatized near-infrared cyanine dyes enable local functional fluorescent imaging of ocular inflammation.

Near-infrared (NIR) chemical fluorophores are promising tools for in-vivo imaging in real time but often succumb to rapid photodegradation. Indocyanine green (ICG) is the only NIR dye with regulatory approval for ocular imaging in humans; however, ICG, when employed for applications such as labelling immune cells, has limited sensitivity and does not allow precise detection of specific inflammatory events, for example leukocyte recruitment during uveitic flare-ups. We investigated the potential use of photostable novel triazole NIR cyanine (TNC) dyes for detecting and characterising activated T-cell activity within the eye. Three TNC dyes were evaluated for ocular cytotoxicity in-vitro using a MTT assay and optimised concentrations for intraocular detection within ex-vivo porcine eyes after topical application or intracameral injections of the dyes. TNC labelled T-cell tracking experiments and mechanistic studies were also performed in-vitro. TNC-1 and TNC-2 dyes exhibited greater fluorescence intensity than ICG at 10 µM, whereas TNC-3 was only detectable at 100 µM within the porcine eye. TNC dyes did not demonstrate any ocular cell toxicity at working concentrations of 10 µM. CD4+T-cells labelled with TNC-1 or TNC-2 were detected within the porcine eye, with TNC-1 being brighter than TNC-2. Detection of TNC-1 and TNC-2 into CD4+T-cells was prevented by prior incubation with dynole 34-2 (50 µM), suggesting active uptake of these dyes via dynamin-dependent processes. The present study provides evidence that TNC dyes are suitable to detect activated CD4+T-cells within the eye with potential as a diagnostic marker for ocular inflammatory diseases.

Multi-responsive mesoporous polydopamine composite nanorods cooperate with nano-enzyme and photosensitiser for intensive immunotherapy of bladder cancer.

Bladder cancer is a common malignancy in the urinary system. Defects of drug molecules in bladder during treatment, such as passive diffusion, rapid clearance of periodic urination, poor adhesion and permeation abilities, lead to low delivery efficiency of conventional drugs and high recurrence rate of disease. In this study, we designed multi-responsive mesoporous polydopamine (PDA) composite nanorods cooperating with nano-enzyme and photosensitiser for intensive immunotherapy of bladder cancer. The strongly adhesive mesoporous PDA with wheat germ agglutinin on nanoparticles could specifically adhere to epithelial glycocalyx and made the nanoparticles aggregate in urinary pathways. Meanwhile, 2,3-dimethylmaleic anhydride could be hydrolysed in acidic conditions of tumour microenvironment, giving it a positive charge (charge reversal), which is more amenable to enter cancer cells. Afterwards, manganese dioxide nanorods could catalyse the reaction of excess H2 O2 in tumour microenvironment to generate active oxygen, so as to change the hypoxic environment in tumour, and achieve a pH-responsive for slow release of PD-L1. After the ICG was irradiated by infrared light, a large amount of singlet oxygen was generated, thereby enhancing the therapeutic effect and reducing toxicity in vivo. Besides, mesoporous PDA with indocyanine green photothermal agent could have a local heat up quickly under the near-infrared light to kill cancer cells, thereby enhancing therapeutic efficacy. Accordingly, this mesoporous PDA composite nanorods shed a light on bladder tumour treatment.

Aqueous angiography in pre-glaucomatous and glaucomatous ADAMTS10-mutant canine eyes: A pilot study.

OBJECTIVE: To evaluate intravenous scleral and intracameral aqueous angiography in normotensive (n = 4) and hypertensive glaucomatous (n = 6) ADAMTS10-mutant canine eyes. ANIMALS STUDIED: Ten ADAMTS10-mutant dogs were used in this study. PROCEDURES: Dogs were sedated and one eye from each dog underwent scleral angiography following intravenous injection of 0.25% indocyanine green (ICG). After a 24-h recovery period, the same eye underwent aqueous angiography via intracameral administration of ICG. Imaging of identical scleral sectors from the same eye was performed using a Heidelberg Spectralis® Confocal Scanning Laser Ophthalmoscope. Intrascleral vessel depth and lumen diameters were measured using Heidelberg Spectralis® optical coherence tomography and computer software. RESULTS: Scleral angiography permitted visualization of vascular components associated with conventional aqueous humor outflow pathways with an average time from injection to fluorescence of 35.8 ± 10.6 s (mean ± SD). Two normotensive eyes (2/10;20%) demonstrated turbulent dye movement, while 4 hypertensive eyes (4/10;40%) exhibited laminar flow. Aqueous angiography demonstrated dye fluorescence within the post-trabecular conventional aqueous humor outflow pathways in all 10 eyes at 34.3 ± 11.0 s post-injection. Sectoral and dynamic outflow patterns were observed primarily within the superotemporal sector in nine eyes (9/10; 90%). Seven eyes (7/10; 70%) demonstrated pulsatile dye movement and five eyes (5/10; 50%) exhibited laminar flow. The degree of laminar movement of dye was greatest in hypertensive eyes. Vessel lumen diameters measured 133.85 ± 28.36 µm and 161.18 ± 6.02 µm in hypertensive and normotensive eyes, respectively. CONCLUSIONS: Aqueous angiography allowed for visualization of fluorescent dye in the superotemporal sclera. Laminar flow and smaller lumen vessels were observed mainly in hypertensive eyes.

Differences in the safety line of the future liver remnant plasma clearance rate of indocyanine green necessary to prevent post-hepatectomy liver failure associated with underlying diseases.

PURPOSE: To evaluate differences in the safety line of the future liver remnant plasma clearance rate of indocyanine green (RemK) necessary to prevent posthepatectomy liver failure (PHLF) associated with liver tumors and comorbidities. METHODS: The subjects of this retrospective study were patients who underwent trisectionectomy, hemihepatectomy, or sectionectomy, other than left lateral sectionectomy, between 2011 and 2018, at the Shizuoka Cancer Center. We analyzed the risk factors for PHLF grades B and C and then evaluated the RemK in these groups, according to various risk factors. RESULTS: A total of 463 patients were selected for the analyses. Among the patients with PHLF grades B and C, those with diabetes mellitus (DM), liver cirrhosis (LC), or hepatocellular carcinoma (HCC) had significantly higher RemK than those without these diseases. Multivariate analysis identified RemK ≤ 0.078, DM, and creatinine clearance rate < 60 mL/min as independent risk factors for PHLF grades B and C. CONCLUSIONS: Hepatectomy for patients with DM, HCC, or LC requires more functional hepatic reserve than that evaluated by RemK.

Assessment of hepatic function, perfusion and parenchyma attenuation with indocyanine green, ultrasound and computed tomography in a healthy rat model: Preliminary determination of baseline parameters in a healthy liver.

BACKGROUND: Defining reference intervals in experimental animal models plays a crucial role in pre-clinical studies. The hepatic parameters in healthy animals provide useful information about type and extension of hepatic damage. However, in the majority of the cases, to obtain them require an invasive techniques. Our study combines these determinations with dynamic functional test and imaging techniques to implement a non-invasive protocol for liver evaluation. The aim of the study was to determine reference intervals for hepatic function, perfusion and parenchyma attenuation with analytical and biochemical blood parameters, indocyanine green, ultrasound and computed tomography in six healthy SD rats. METHODS: Six males healthy SD rats were followed for 4 weeks. To determine hepatic function, perfusion and parenchyma attenuation analytical and biochemical blood parameters, indocyanine green, ultrasound and computed tomography were studied. Results were expressed as Means ± standard error of mean (SEM). The significance of differences was calculated by using student t-test, p < 0.05 was considered statistically significant. RESULTS: Indocyanine green clearance 5 and 10 minutes after its injection was 80.12% and 96.59%, respectively. Approximate rate of decay during the first 5 minutes after injection was 38% per minute. Hepatic perfusion evaluation with the high-frequency ultrasound was related to cardiovascular hemodynamic and renal perfusion. Portal area, hepatic artery resistance index, hepatic artery and portal peak systolic velocity and average between hepatic artery and porta was 3.41 ± 0.62 mm2, 0.57 ± 0.04 mm2/s, 693.24±102.53 mm2/s, 150.72 ± 17.80 mm2/s and 4.82 ± 0.96 mm2/s, respectively. Heart rate, cardiac output, left renal artery diammetre and renal blood flow were 331.01 ± 22.22 bpm, 75.58 ± 8.72 mL/min, 0.88 ± 0.04 mm2 and 13.65 ± 1.95 mm2/s. CT-scan hepatic average volume for each rat were 21.08±3.32, 17.57±2.76, 14.87±2.83 and 13.67±2.45 cm3 with an average attenuation coefficient of 113.51±18.08, 129,19±7.18, 141,47±1.95 y 151,67±1.2 HU. CONCLUSION: Indocyanine green and high-frequency ultrasound could be used in rats as a suitable marker of liver function. Computed tomography, through the study of raw data, help to characterize liver parenchyma, and could be a potential tool for early detection of liver parenchymal alterations and linear follow-up of patients. Further studies in rats with liver disease are necessary to verify the usefulness of these parameters.

Association between the donor to recipient ICG-PDR variation rate and the functional recovery of the graft after orthotopic liver transplantation: A case series.

BACKGROUND: Despite current advances in liver transplant surgery, post-operative early allograft dysfunction still complicates the patient prognosis and graft survival. The transition from the donor has not been yet fully understood, and no study quantifies if and how the liver function changes through its transfer to the recipient. The indocyanine green dye plasma disappearance rate (ICG-PDR) is a simple validated tool of liver function assessment. The variation rate between the donor and recipient ICG-PDR still needs to be investigated. MATERIALS AND METHODS: Single-center retrospective study. ICG-PDR determinations were performed before graft retrieval (T1) and 24 hours after transplant (T2). The ICG-PDR relative variation rate between T1 and T2 was calculated to assess the graft function and suffering/recovering. Matched data were compared with the MEAF model of graft dysfunction. OBJECTIVE: To investigate whether the variation rate between the donor ICG-PDR value and the recipient ICG-PDR measurement on first postoperative day (POD1) can be associated with the MEAF score. RESULTS: 36 ICG-PDR measurements between 18 donors and 18 graft recipients were performed. The mean donor ICG-PDR was 22.64 (SD 6.35), and the mean receiver's ICG-PDR on 1st POD was 17.68 (SD 6.60), with a mean MEAF value of 4.51 (SD 1.23). Pearson's test stressed a good, linear inverse correlation between the ICG-PDR relative variation and the MEAF values, correlation coefficient -0.580 (p = 0.012). CONCLUSION: The direct correlation between the donor to recipient ICG-PDR variation rate and MEAF was found. Measurements at T1 and T2 showed an up- or downtrend of the graft performance that reflect the MEAF values.

Quantitative Radionuclide Imaging Analysis of Enhanced Drug Delivery Induced by Photoimmunotherapy.

Photoimmunotherapy (PIT) is an upcoming potential cancer treatment modality, the effect of which is improved in combination with chemotherapy. PIT causes a super-enhanced permeability and retention (SUPR) effect. Here, we quantitatively evaluated the SUPR effect using radiolabeled drugs of varying molecular weights (18F-5FU, 111In-DTPA, 99mTc-HSA-D, and 111In-IgG) to determine the appropriate drug size. PIT was conducted with an indocyanine green-labeled anti-HER2 antibody and an 808 nm laser irradiation. Mice were subcutaneously inoculated with HER2-positive cells in both hindlimbs. The tumor on one side was treated with PIT, and the contralateral side was not treated. The differences between tumor accumulations were evaluated using positron emission tomography or single-photon emission computed tomography. Imaging studies found increased tumor accumulation of agents after PIT. PIT-treated tumors showed significantly increased uptake of 18F-5FU (p < 0.001) and 99mTc-HSA-D (p < 0.001). A tendency toward increased accumulation of 111In-DTPA and 111In-IgG was observed. These findings suggest that some low- and medium-molecular-weight agents are promising candidates for combined PIT, as are macromolecules; hence, administration after PIT could enhance their efficacy. Our findings encourage further preclinical and clinical studies to develop a combination therapy of PIT with conventional anticancer drugs.

An adaptable and non-invasive method for tracking Bifidobacterium animalis subspecies lactis 420 in the mouse gut.

Probiotic strains from the Bifidobacterium or Lactobacillus genera improve health outcomes in models of metabolic and cardiovascular disease. Yet, underlying mechanisms governing these improved health outcomes are rooted in the interaction of gut microbiota, intestinal interface, and probiotic strain. Central to defining the underlying mechanisms governing these improved health outcomes is the development of adaptable and non-invasive tools to study probiotic localization and colonization within the host gut microbiome. The objective of this study was to test labeling and tracking efficacy of Bifidobacterium animalis subspecies lactis 420 (B420) using a common clinical imaging agent, indocyanine green (ICG). ICG was an effective in situ labeling agent visualized in either intact mouse or excised gastrointestinal (GI) tract at different time intervals. Quantitative PCR was used to validate ICG visualization of B420, which also demonstrated that B420 transit time matched normal murine GI motility (~8 hours). Contrary to previous thoughts, B420 did not colonize any region of the GI tract whether following a single bolus or daily administration for up to 10 days. We conclude that ICG may provide a useful tool to visualize and track probiotic species such as B420 without implementing complex molecular and genetic tools. Proof-of-concept studies indicate that B420 did not colonize and establish residency align the murine GI tract.

Intraoperative quality assessment of tissue perfusion with indocyanine green (ICG) in a porcine model of mesenteric ischemia.

BACKGROUND: Mesenteric ischemia is a severe and potentially lethal event. Assessment of intestine perfusion is eminently depending on the skills, and the experience of the surgeon. Thus, the therapy is biased by the right evaluation. Aim of this study is to determine the applicability, and the usefulness of fluorescent-imaging (FI) with indocyanine green (ICG) in a porcine model of mesenteric ischemia. Second end-point is the verification of a visual and quantitative assessment tool of the intestinal perfusion. METHODS: In 18 pigs (54,2 ±2,9kg) an occlusion of a side-branch of the mesenteric artery was performed for 3 (group I, n = 7), 6 (group II, n = 7), and 10 hours (group III, n = 4). After reperfusion a 60 minutes observation period was carried out. 3 regions of interest were defined: ischemic bowel (D1), transitional zone (D2), and non-ischemic bowel (D3). ICG-FI was performed during baseline (T0), occlusion (T1), reperfusion (T2) and after an observation period of 60 minutes (T4). RESULTS: All experiments could be finished successfully. ICG-FI was assessed using assessment of background-subtracted peak fluorescence intensity (BSFI), slope of fluorescence intensity (SFI), and a baseline adjusted ratio of both parameters. ICG-FI confirmed loss of perfusion in D1, decreased perfusion in D2, and increased perfusion in D3. After reperfusion ICG-FI increased in group 2 due to a severe tissue damage resulting in a capillary leakage. In group I ICG-FI was equal to baseline values indicating the totally reversible loss of perfusion. CONCLUSION: Using ICG-FI to estimate intestine perfusion after different durations of ischemia is viable using a porcine model of mesenteric ischemia. Even small differences in perfusion can be reliably determined by ICG-FI. Thus, ICG-FI is an encouraging method to evaluate intestine perfusion intraoperatively.

Evaluating the Effect of Intraoperative Near-Infrared Observation on Anastomotic Leakage After Stapled Side-to-Side Anastomosis in Colon Cancer Surgery Using Propensity Score Matching.

BACKGROUND: Recent studies have clarified that near-infrared observation using indocyanine green has the advantage of evaluating perfusion of the anastomotic site, especially in rectal cancer surgery, resulting in a reduction in anastomotic leak. OBJECTIVE: The aim of this study was to evaluate the efficacy of near-infrared observation for reducing the anastomotic leak after stapled side-to-side anastomosis in colon cancer surgery. DESIGN: This was a retrospective propensity score case-matched study. SETTINGS: The study was conducted at 3 institutions in the Yokohama Clinical Oncology Group. PATIENTS: From January 2011 to December 2019, patients who underwent colon cancer surgery with stapled side-to-side anastomosis were included. MAIN OUTCOME MEASURES: The main outcome was the percentage of anastomotic leak within 30 days after surgery. RESULTS: A total of 1034 patients were collected. There were 532 patients who underwent near-infrared observation and 502 who did not. A total of 370 patients were matched to the near-infrared and non-near-infrared groups. In the near-infrared group, 12 patients (3.2%) were judged to have poor perfusion (4 patients) and no perfusion (8 patients), so the planned transection point was changed. There were no cases of anastomotic leak among these 12 patients. The anastomotic leak rates were 3.5% (13/370) in the non-near-infrared group and 0.8% (3/370) in the near-infrared group. The anastomotic leak and reoperation rates were significantly lower in the near-infrared group than in the non-near-infrared group (OR, 0.224; 95% CI, 0.063-0.794, p = 0.001; OR, 0.348; 95% CI, 0.124-0.977, p = 0.036). LIMITATIONS: Although we reduced selection bias by performing propensity score matching, this was a retrospective study and was not randomized. CONCLUSION: This large-scale case-matched study showed that assessing perfusion by near-infrared observation significantly reduced the anastomotic leak and reoperation rates after stapled side-to-side anastomosis in colon cancer surgery and may be better suited to colo-colonic anastomosis. Video Abstract at http://links.lww.com/DCR/B513.Japanese Clinical Trials Registry: UMIN-CTR000039977. EVALUACIN DEL EFECTO DE LA OBSERVACIN INTRAOPERATORIA CON INFRARROJO CERCANO SOBRE LA FUGA ANASTOMTICA DESPUS DE UNA ANASTOMOSIS LATEROLATERAL CON ENGRAPADORA EN LA CIRUGA DE CNCER DE COLON MEDIANTE EL EMPAREJAMIENTO POR PUNTAJES DE PROPENSIN: ANTECEDENTES:Estudios recientes han aclarado que la observación con infrarrojo cercano con verde de indocianina tiene la ventaja de evaluar la perfusión del sitio anastomótico, especialmente en la cirugía de cáncer de recto, lo que resulta en una reducción de la fuga anastomótica.OBJETIVO:El objetivo de este estudio fue evaluar la eficacia de la observación con infrarrojo cercano para reducir la fuga anastomótica después de una anastomosis latero-lateral con engrapadora en la cirugía de cáncer de colon.DISEÑO:Este fue un estudio retrospectivo emparejado con puntaje de propensión.AJUSTE:El estudio se llevó a cabo en tres instituciones del Grupo de Oncología Clínica de Yokohama.PACIENTES:Desde enero de 2011 hasta diciembre de 2019, se incluyeron pacientes que se sometieron a cirugía de cáncer de colon con anastomosis latero-lateral con engrapadora.PRINCIPALES MEDIDAS DE RESULTADO:El resultado principal fue el porcentaje de fuga anastomótica dentro de los 30 días posteriores a la cirugía.RESULTADOS:Se recogió un total de 1034 pacientes. Hubo 532 pacientes que se sometieron a observación con infrarrojo cercano y 502 que no. Un total de 370 pacientes fueron emparejados con los grupos de infrarrojo cercano y no infrarrojo cercano. En el grupo de infrarrojo cercano, se consideró que 12 casos (3,2%) tenían mala perfusión (4 casos) y ninguna perfusión (8 casos), por lo que se cambió el punto de transección planificado. No hubo casos de fuga anastomótica entre estos 12 casos. Las tasas de fuga anastomótica fueron del 3,5% (13/370) en el grupo sin infrarrojo cercano y del 0,8% (3/370) en el grupo con infrarrojo cercano. Las tasas de fuga anastomótica y de reintervención fueron significativamente menores en el grupo con infrarrojo cercano que en el grupo sin infrarrojo cercano (razón de posibilidades 0,224, intervalo de confianza del 95% 0,063-0,794, p = 0,001; razón de posibilidades 0,348, intervalo de confianza del 95% 0,124 -0,977, p = 0,036, respectivamente).LIMITACIONES:Aunque se redujo el sesgo de selección al realizar el emparejamiento por puntaje de propensión, este fue un estudio retrospectivo y no fue aleatorio.CONCLUSIÓN:Este estudio de casos emparejados a gran escala demostró que la evaluación de la perfusión mediante la observación con infrarrojo cercano redujo significativamente la fuga anastomótica y las tasas de reintervención después de la anastomosis latero-lateral con engrapadora en la cirugía de cáncer de colon y puede ser más adecuada para la anastomosis colo-colónica. Consulte Video Resumen en http://links.lww.com/DCR/B513.Registro japonés de ensayos clínicos: UMIN-CTR000039977.

Structurally symmetric near-infrared fluorophore IRDye78-protein complex enables multimodal cancer imaging.

Rationale: Most contemporary cancer therapeutic paradigms involve initial imaging as a treatment roadmap, followed by the active engagement of surgical operations. Current approved intraoperative contrast agents exemplified by indocyanine green (ICG) have a few drawbacks including the inability of pre-surgical localization. Alternative near-infrared (NIR) dyes including IRDye800cw are being explored in advanced clinical trials but often encounter low chemical yields and complex purifications owing to the asymmetric synthesis. A single contrast agent with ease of synthesis that works in multiple cancer types and simultaneously allows presurgical imaging, intraoperative deep-tissue three-dimensional visualization, and high-speed microscopic visualization of tumor margins via spatiotemporally complementary modalities would be beneficial. Methods: Due to the lack of commercial availability and the absence of detailed synthesis and characterization, we proposed a facile and scalable synthesis pathway for the symmetric NIR water-soluble heptamethine sulfoindocyanine IRDye78. The synthesis can be accomplished in four steps from commercially-available building blocks. Its symmetric resonant structure avoided asymmetric synthesis problems while still preserving the benefits of analogous IRDye800cw with commensurable optical properties. Next, we introduced a low-molecular-weight protein alpha-lactalbumin (α-LA) as the carrier that effectively modulates the hepatic clearance of IRDye78 into the preferred renal excretion pathway. We further implemented 89Zr radiolabeling onto the protein scaffold for positron emission tomography (PET). The multimodal imaging capability of the fluorophore-protein complex was validated in breast cancer and glioblastoma. Results: The scalable synthesis resulted in high chemical yields, typically 95% yield in the final step of the chloro dye. Chemical structures of intermediates and the final fluorophore were confirmed. Asymmetric IRDye78 exhibited comparable optical features as symmetric IRDye800cw. Its well-balanced quantum yield affords concurrent dual fluorescence and optoacoustic contrast without self-quenching nor concentration-dependent absorption. The NHS ester functionality modulates efficient covalent coupling to reactive side-chain amines to the protein carrier, along with desferrioxamine (DFO) for stable radiolabeling of 89Zr. The fluorophore-protein complex advantageously shifted the biodistribution and can be effectively cleared through the urinary pathway. The agent accumulates in tumors and enables triple-modal visualization in mouse xenograft models of both breast and brain cancers. Conclusion: This study described in detail a generalized strategic modulation of clearance routes towards the favorable renal clearance, via the introduction of α-LA. IRDye78 as a feasible alternative of IRDye800cw currently in clinical phases was proposed with a facile synthesis and fully characterized for the first time. This fluorophore-protein complex with stable radiolabeling should have great potential for clinical translation where it could enable an elegant workflow from preoperative planning to intraoperative deep tissue and high-resolution image-guided resection.

Timing of indocyanine green injection prior to laparoscopic colorectal surgery for tumor localization: a prospective case series.

BACKGROUND: Accurate identification of tumor sites during laparoscopic colorectal surgery helps to optimize oncological clearance. We aimed to assess the timing of the local injection preoperatively and clarify the usefulness and limitation of tumor site marking using indocyanine green (ICG) fluorescence imaging. METHODS: Consecutive patients who underwent primary colorectal cancer surgery from September 2017 to January 2019 were included. Preoperatively, lower endoscopy was used to inject the ICG solution into the submucosal layer near the tumor. During laparoscopic surgery, ICG fluorescence marking as the tumor site marking was detected using a laparoscopic near-infrared camera system. The detection rate and factors associated with successful intraoperative ICG fluorescence visualization including the interval between local injection and surgery were evaluated. RESULTS: One hundred sixty-five patients were enrolled. Using the laparoscopic near-infrared system, the intraoperative detection rates of ICG marking were 100% for ICG injection within 6 days preoperatively, 60% for injection between 7 and 9 days preoperatively, and 0% for injection earlier than 10 days preoperatively. There were no complications associated with ICG marking. Additionally, this method did not disturb the progress of the surgical procedure because injected ICG in the submucosal layer did not cause any tissue inflammation, and if ICG spilled into the serosa, it was invisible by white light. CONCLUSION: Advantages of ICG fluorescence tumor site marking were high visibility of infrared imaging during laparoscopic colorectal surgery and minimal adverse events of surgery. One of the most important findings regarding practical use was a rapid decrease in fluorescence marking visibility if one week passed from the time of ICG local injection.

Folic Acid-Modified Erythrocyte Membrane Loading Dual Drug for Targeted and Chemo-Photothermal Synergistic Cancer Therapy.

To overcome the challenges of systemic toxicity and weak tumor selectivity caused by traditional antitumor drugs, numerous nanocarrier systems have been developed in recent decades, and their therapeutic effect has been improved to varying degrees. However, because of the drug resistance effect and metastasis involved in tumor recurrence, a single chemotherapy can no longer satisfy the diversified treatment needs. Recently, the application of chemotherapy in combination with thermotherapy as a synergistic approach has been proven to be more effective, and it provides a new strategy for cancer therapy. In this work, by utilizing the unique properties of erythrocytes, a surface-modified erythrocyte membrane was constructed as a novel nanocarrier system (DOX and ICG-PLGA@RBC nanoparticles, DIRNPs for short) for the simultaneous transportation of chemotherapeutic drugs (doxorubicin, DOX) and photothermal agents (indocyanine green, ICG) to achieve the effects of long-term circulation, active tumor targeting, and triggered drug release. The results indicated that DIRNPs have a nanoscale particle size of 158.4 nm with a narrow size distribution and a negative surface charge of -5.79 mV. No particle aggregation or remarkable drug leakage was observed during the 30 day storage test, and because of the excellent photothermal conversion ability of ICG, the local temperature of DIRNPs could dramatically increase from 33.7 to 49.8 °C in 10 min under near-infrared (NIR) laser irradiation. The in vitro drug dissolution data demonstrated that the DOX release from the DIRNPs was pH-dependent and NIR-triggered. Folic acid modifications of the erythrocyte membrane effectively facilitated the intracellular uptake of DIRNPs by HepG2 cells and, as a result, it significantly inhibited tumor cell growth, promoted reactive oxygen species levels, induced cell apoptosis, and restricted cell recovery and migration. In vivo pharmacokinetics and biodistribution studies indicated that the DIRNPs prolonged the half-life of DOX from 6.03 to 17.6 h and remarkably reduced the DOX level in the heart to avoid drug-related cardiotoxicity. More importantly, the DIRNPs exerted excellent in vivo antitumor efficacy against H22 tumors with superior safety. In conclusion, utilizing the advantageous properties of erythrocytes to construct a tumor-targeted biomimetic nanocarrier for codelivery of chemotherapeutics and photothermal agents to produce synergistic effects is considered an effective method for cancer therapy.

Synthesis, characterization and optimization of in vitro properties of NIR-fluorescent cyclic α-MSH peptides for melanoma imaging.

Melanoma are malignant tumors derived from melanocytes being responsible for the majority of skin cancer deaths with an increasing rate of incidence. The Melanocortin-1 receptor (MC1R) has been recognized as a molecular target for melanoma detection. Here, we report on the development and optimization of molecular probes which are based on novel conjugates of near-infrared (NIR) fluorescent indocyanine dyes and an MC1R-targeting peptide intended for optical fluorescence imaging enabling an early, specific, accurate and sensitive diagnosis of malignant melanomas. The introduction of anionic groups into the aromatic ring of the indolenine substructure of the conjugated dyes has shown to result in a strong fluorescence in aqueous solution and a concomitant increase of binding affinities of the peptide conjugates to the target receptor. The length and flexibility of the PEG chain introduced as a linker, as well as the nature of its attachment to the dye also affect the binding affinities, albeit to a lower extent. The conjugates have been successfully applied in the MC1R-specific staining of B16F10 melanoma cells, both in cell cultures and in microtome sections of solid tumors.