Octreotide improves human lymphatic fluid transport a translational trial

OBJECTIVES

Chylothorax is a complex condition and many different pharmacological agents have been tried as treatment. Octreotide is used off-label to treat chylothorax, but the efficacy of octreotide remains unclear. A decrease in lymph production is suggested as the mechanism. In this cross-over study, we explore the direct effect of octreotide on human lymphatic drainage.

METHODS

Pre-clinical: the effect of octreotide on force generation was assessed during acute and prolonged drug incubation on human lymphatic vessels mounted in a myograph. Clinical: in a double-blinded, randomized, cross-over trial including 16 healthy adults, we administered either octreotide or saline as an intravenous infusion for 2.5 h. Near-infrared fluorescence imaging was used to examine spontaneous lymphatic contractions and lymph pressure in peripheral lymphatic vessels and plethysmography was performed to assess the capillary filtration rate, capillary filtration coefficient and isovolumetric pressures of the lower leg.

RESULTS

Pre-clinical: human thoracic duct (n = 12) contraction rate was concentration-dependently stimulated by octreotide with a maximum effect at 10 and 100 nmol/l in the myograph chamber. Clinical: spontaneous lymphatic contractions and lymph pressure evaluated by near-infrared fluorescence did not differ between octreotide or placebo (P = 0.36). Plethysmography revealed similar capillary filtration coefficients (P = 0.057), but almost a doubling of the isovolumetric pressures (P = 0.005) during octreotide infusion.

CONCLUSIONS

Octreotide stimulated lymphatic contractility in the pre-clinical setup but did not affect the spontaneous lymphatic contractions or lymph pressure in healthy individuals. Plethysmography revealed a doubling in the isovolumetric pressure. These results suggest that octreotide increases lymphatic drainage capacity in situations with high lymphatic afterload.

A multicenter noninferior randomized controlled study of sentinel lymph node biopsy alone versus sentinel lymph node biopsy plus lymphadenectomy for patients with stage I endometrial cancer, INSEC trial concept

BACKGROUND

Up to the present time, there has remained a lack of strong evidence as to whether sentinel lymph node biopsy can replace lymphadenectomy for early endometrial cancer. The traditional surgery for endometrial cancer includes pelvic lymphadenectomy and paraaortic lymph node resection, but complications often seriously affect patients' quality of life. Two randomized controlled trials with large samples have proved that lymphadenectomy does not improve the overall recurrence rate and survival rate of patients. On the contrary, it increases the incidence of complications and even mortality. The current trial is designed to clarify whether sentinel lymph node biopsy can replace lymphadenectomy for early endometrial cancer patients with negative lymph nodes.

METHODS

This study is a randomized, open-label, multicenter and non-inferiority controlled clinical trial in China. Potential participants will be patients with pathologically confirmed endometrial cancer at the Zhejiang Cancer Hospital, Jiaxing Maternity and Child Health Care Hospital, and the First Hospital of Jiaxing in China. The total sample size for this study is 722. Patients will be randomly assigned in a 1:1 ratio to two groups. Patients in one group will undergo sentinel lymph node biopsy + total hysterectomy + bilateral salpingo-oophorectomy ± paraaortic lymph node resection. Patients in the other group will undergo sentinel lymph node biopsy + total hysterectomy + bilateral salpingo-oophorectomy + pelvic lymphadenectomy ± paraaortic lymph node resection. The 3-year disease-free survival rate, overall survival rate, quality of life (use EORTC QLQ-C30 + QLQ-CX24), and perioperative related indexes of the two groups will be compared.

RESULTS

We expect to find that for patients with early endometrial cancer, the 3-year disease-free survival rate following sentinel lymph node biopsy with indocyanine green combined with near-infrared fluorescence imaging is similar to that following lymphadenectomy. The operation time, as well as incidence of pelvic lymphocyst, lymphedema of lower limb, and edema of vulva in patients who only undergo sentinel lymph node biopsy are expected to be significantly lower than in patients who undergo lymphadenectomy. The quality of life of patients who undergo sentinel lymph node biopsy alone will be significantly better than that of patients who undergo lymph node dissection.

CONCLUSION

This will prove that the prognosis of sentinel lymph node biopsy alone with indocyanine green combined with near-infrared fluorescence imaging is not inferior to that of sentinel lymph node biopsy plus lymphadenectomy for early stage endometrial cancer with negative nodal assessment intraoperatively. In addition, sentinel lymph node biopsy alone with indocyanine green combined with near-infrared fluorescence imaging results in fewer surgical complications and gives patients better quality of life.

TRIAL REGISTRATION

chictr.org.cn, ChiCTR1900023161. Registered 14 May 2019, http://www.chictr.org.cn/edit.aspx?pid=38659&htm=4 .

A novel PSMA targeted dual-function near-infrared fluorescence and PET probe for the image-guided surgery and detection of prostate cancer

PURPOSE

Prostate-specific membrane antigen (PSMA) is a promising diagnostic biomarker for prostate cancer (PCa). NYM016, a novel small-molecule PSMA-targeted fluorescence probe for the surgical navigation of PCa, was designed in this work. Furthermore, the potential of the PET agent [68Ga]Ga-NYM016 for the radionuclide imaging of PCa was evaluated.

METHODS

NYM016 was designed with the near-infrared fluorescent group Cyanine 7 (Cy7) and the chelating group NOTA. The radioactive probe [68Ga]Ga-NYM016 was designed and synthesized on the basis of NYM016. The abovementioned probes were assessed in PSMA-positive xenograft-bearing models and patients diagnosed with PCa.

RESULTS

NYM016 obviously aggregated in the tumor site of the mouse model, and its fluorescence intensity was stable within 24 h. NYM016 was well-tolerated, and no adverse events were found in the clinical study. Moreover, it was also observed in the excised lesions from the patient with PCa, and its fluorescence aggregated at the same site where PSMA was highly expressed. In addition, the PSMA xenograft demonstrated intense [68Ga]Ga-NYM016 uptake at 2.5 min after injection. At 3 h after injection, [68Ga]Ga-NYM016 uptake by the PSMA xenograft gradually increased to 6.40 ± 0.19%ID/g, which was higher that by the blocked and negative groups (2.28 ± 0.07%ID/g, P < 0.05; 2.28 ± 0.22%ID/g, P < 0.05). In the clinical study, [68Ga]Ga-NYM016 was well-tolerated and no adverse events were observed. Substantial accumulation was observed in primary and metastatic lesions in a patient with recurrence with the maximum standardized uptake value of 18.93. Meanwhile, negative [68Ga]Ga-NYM016 uptake was observed at the prostate site of a patient with prostatitis.

CONCLUSION

The novel fluorescence probe NYM016 and the radioactive tracer [68Ga]Ga-NYM016 are promising candidates for the surgical navigation and radionuclide imaging of PCa, respectively.

TRIAL REGISTRATION

The clinical evaluation of this study was registered at Clinicaltrial.gov (NCT05623878) on 21 Dec, 2022.

Advancements in Intraoperative Near-Infrared Fluorescence Imaging for Accurate Tumor Resection: A Promising Technique for Improved Surgical Outcomes and Patient Survival

Clear surgical margins for solid tumor resection are essential for preventing cancer recurrence and improving overall patient survival. Complete resection of tumors is often limited by a surgeon's ability to accurately locate malignant tissues and differentiate them from healthy tissue. Therefore, techniques or imaging modalities are required that would ease the identification and resection of tumors by real-time intraoperative visualization of tumors. Although conventional imaging techniques such as positron emission tomography (PET), computed tomography (CT), magnetic resonance imaging (MRI), or radiography play an essential role in preoperative diagnostics, these cannot be utilized in intraoperative tumor detection due to their large size, high cost, long imaging time, and lack of cancer specificity. The inception of several imaging techniques has paved the way to intraoperative tumor margin detection with a high degree of sensitivity and specificity. Particularly, molecular imaging using near-infrared fluorescence (NIRF) based nanoprobes provides superior imaging quality due to high signal-to-noise ratio, deep penetration to tissues, and low autofluorescence, enabling accurate tumor resection and improved survival rates. In this review, we discuss the recent developments in imaging technologies, specifically focusing on NIRF nanoprobes that aid in highly specific intraoperative surgeries with real-time recognition of tumor margins.

Intraoperative molecular imaging of colorectal lung metastases with SGM-101: a feasibility study

PURPOSE

Metastasectomy is a common treatment option for patients with colorectal lung metastases (CLM). Challenges exist with margin assessment and identification of small nodules, especially during minimally invasive surgery. Intraoperative fluorescence imaging has the potential to overcome these challenges. The aim of this study was to assess feasibility of targeting CLM with the carcinoembryonic antigen (CEA) specific fluorescent tracer SGM-101.

METHODS

This was a prospective, open-label feasibility study. The primary outcome was the number of CLM that showed a true positive fluorescence signal with SGM-101. Fluorescence positive signal was defined as a signal-to-background ratio (SBR) ≥ 1.5. A secondary endpoint was the CEA expression in the colorectal lung metastases, assessed with the immunohistochemistry, and scored by the total immunostaining score.

RESULTS

Thirteen patients were included in this study. Positive fluorescence signal with in vivo, back table, and closed-field bread loaf imaging was observed in 31%, 45%, and 94% of the tumors respectively. Median SBRs for the three imaging modalities were 1.00 (IQR: 1.00-1.53), 1.45 (IQR: 1.00-1.89), and 4.81 (IQR: 2.70-7.41). All tumor lesions had a maximum total immunostaining score for CEA expression of 12/12.

CONCLUSION

This study demonstrated the potential of fluorescence imaging of CLM with SGM-101. CEA expression was observed in all tumors, and closed-field imaging showed excellent CEA specific targeting of the tracer to the tumor nodules. The full potential of SGM-101 for in vivo detection of the tracer can be achieved with improved minimal invasive imaging systems and optimal patient selection.

TRIAL REGISTRATION

The study was registered in ClinicalTrial.gov under identifier NCT04737213 at February 2021.

Identification of a CEACAM5 targeted nanobody for positron emission tomography imaging and near-infrared fluorescence imaging of colorectal cancer

PURPOSE

Here, we aim to identify a CEACAM5-targeted nanobody and demonstrate its application in positron emission tomography (PET) imaging and near-infrared (NIR) fluorescence imaging in colorectal cancer (CRC).

METHODS

Immunohistochemistry was applied to verify CEACAM5 expression in CRC and metastatic lymph nodes (mLNs). CEACAM5-targeted nanobodies were obtained by immunization of human CEACAM5 protein in a dromedary, followed by several rounds of phage screenings. Immunofluorescence staining and flow cytometry was carried out to determine the binding affinity of the nanobodies. The nanobodies were radiolabeled by coupling 18F-SFB for PET imaging of CRC subcutaneous xenografts and lymph node metastasis (LNM). IRDye800CW (IR800) were conjugated to form NIR probes for NIR imaging in CRC subcutaneous models.

RESULTS

CEACAM5 was overexpressed in either human CRC tissues or mLNs. A CEACAM5 targeted nanobody, Nb41 was successfully generated, with excellent in vitro binding properties. Incorporation of albumin binding domain (ABD) did not affect the affinity of Nb41. In vivo imaging showed that both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed obvious accumulation in the tumor. Due to the longer retention in the blood, 18F-FB-Nb41-ABD enrichment in tumors was significantly delayed but higher compared to 18F-FB-Nb41. Both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed prominent LNM enrichment. Similarly, the IR800-conjugated nanobodies Nb41-IR800 and Nb41-ABD-IR800 exhibited superior imaging effects in subcutaneous models, while Nb41-ABD-IR800 exhibited higher fluorescence intensity in the tumor accompanied with a remarkedly delay compared to Nb41-IR800.

CONCLUSION

Collectively, we presented the identification and in vivo validation of a CEACAM5-targeted nanobody and a fused nanobody with an ABD, which enabled to the non-invasive visualization of malignancy of CRC using PET imaging and NIR imaging in subcutaneous models as well as LNM models.

Detection of Colorectal Liver Metastases Using Near-Infrared Fluorescence Imaging During Hepatectomy: Prospective Single Centre UK Study

INTRODUCTION

Small superficial colorectal liver metastases (CLM) may be difficult to localise intraoperatively, especially during minimally invasive hepatectomy due to reduced tactile feedback and limitations of ultrasound (US). Near-infrared (NIRF) fluorescence imaging is an emerging technology that permits detection of liver tumours after systemic injection of indocyanine green (ICG). Our aim was to report our experience using NIRF to detect CLM.

PATIENTS AND METHODS

Patients with small, superficial resectable CLM received a 10-mg IV bolus of ICG the day before hepatectomy. All patients underwent preoperative liver-specific MRI. CLM were localised intraoperatively using a combination of white light/ultrasound (WL-US) and NIRF. Sensitivity and specificity of NIRF were compared with WL-US.

RESULTS

Between March 2019 and July 2021, NIRF was utilised in 15 patients who underwent hepatectomy (laparoscopic 13, open 2). Thirty-two lesions were detected by MRI (including 3 disappearing CLM), of which 2 were ICG-negative and not resected (1 haemangioma, 1 disappearing CLM). Of 30 resected lesions, the median tumour diameter was 11 mm (range 2-25), median distance from liver surface was 4.5 mm (range 0-20) and all were confirmed CLM on histology (R0 resection rate 71%). Twenty-three of thirty (77%) and twenty-seven of thirty (90%) resected CLM were detected by WL-US and NIRF, respectively. Of 7/30 (23%) resected CLM that were WL-US negative, 5 were ICG-positive. Two resected 'disappearing' CLM were ICG-positive, one of which contained viable cancer cells. Overall, NIRF influenced the operative strategy in 6 patients (43%).

CONCLUSION

Near-infrared fluorescence imaging allows detection of small, superficial colorectal liver metastases that are missed by conventional techniques and warrants further study.

Fluorescence-based sentinel lymph node mapping and lymphography evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

The identification of metastatic lymph nodes is one of the most important prognostic factors in gastrointestinal (GI) cancers. Near-infrared fluorescence (NIRF) imaging has been successfully used in GI tumors to detect the lymphatic pathway and the sentinel lymph node (SLN), facilitating fluorescence image-guided surgery (FIGS) with the purpose to achieve a correct nodal staging. The aim of this study was to analyze the current results of NIRF SLN navigation and lymphography through data collected in the EURO-FIGS registry.

METHODS

Prospectively collected data regarding patients and ICG-guided lymphadenectomies were analyzed. Additional analyses were performed to identify predictors of metastatic SLN and determinants of fluorescence positivity and nodal metastases outside the boundaries of standard lymphadenectomies.

RESULTS

Overall, 188 patients were included by 18 surgeons from 10 different centers. Colorectal cancer was the most reported pathology (77.7%), followed by gastric (19.1%) and esophageal tumors (3.2%). ICG was injected with higher doses (p < 0.001) via extraparietal side (63.3%), and with higher volumes (p < 0.001) via endoluminal side (36.7%). Overall, NIRF SLN navigation was positive in 75.5% of all cases and 95.5% of positive SLNs were retrieved, with a metastatic rate of 14.7%. NIRF identification of lymph nodes outside standard lymphatic stations occurred in 52.1% of all cases, 43.8% of which were positive for metastatic involvement. Positive NIRF SLN identification was an independent predictor of metastasis outside standard lymphatic stations (OR = 4.392, p = 0.029), while BMI independently predicted metastasis in retrieved SLNs (OR = 1.187, p = 0.013). Lower doses of ICG were protective against NIRF identification outside standard of care lymphadenectomy (OR = 0.596, p = 0.006), while higher volumes of ICG were predictive of metastatic involvement outside standard of care lymphadenectomy (OR = 1.597, p = 0.001).

CONCLUSIONS

SLN mapping helps identifying potentially metastatic lymph nodes outside the boundaries of standard lymphadenectomies. The EURO-FIGS registry is a valuable tool to share and analyze European surgeons' practices.

Practical Guidance for Developing Small-Molecule Optical Probes for In Vivo Imaging

The WMIS Education Committee (2019-2022) reached a consensus that white papers on molecular imaging could be beneficial for practitioners of molecular imaging at their early career stages and other scientists who are interested in molecular imaging. With this consensus, the committee plans to publish a series of white papers on topics related to the daily practice of molecular imaging. In this white paper, we aim to provide practical guidance that could be helpful for optical molecular imaging, particularly for small molecule probe development and validation in vitro and in vivo. The focus of this paper is preclinical animal studies with small-molecule optical probes. Near-infrared fluorescence imaging, bioluminescence imaging, chemiluminescence imaging, image-guided surgery, and Cerenkov luminescence imaging are discussed in this white paper.

In vivo near-infrared fluorescence and SPECT-CT imaging of colorectal Cancer using the bradykinin B2R-specific ligand icatibant

Cancer molecular imaging using specific probes designed to identify target proteins in cancer is a powerful tool to guide therapeutic selection, patient management, and follow-up. We demonstrated that icatibant may be used as a targeting probe for the significantly upregulated bradykinin B2R in colorectal cancer (CRC). Icatibant-based probes with high affinity towards bradykinin B2R were identified. The near-infrared (NIR) fluorescent dye conjugate MPA-PEG₃-k-Icatibant and radioconjugate [^99mTc]Tc-HYNIC-PEG₄-Icatibant exhibited favourable selective and specific uptake in tumours when the subcutaneous and orthotopic colorectal tumour-bearing mouse models were imaged using NIR fluorescence imaging and Single-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT), respectively. The tracer of [^99mTc]Tc-HYNIC-PEG₄-Icatibant accumulated in tumours according to biodistribution studies and peaked at 4 h with an uptake value of 3.41 ± 0.27%ID/g in HT29 tumour-bearing nude mice following intravenous injection (i.v.). The tumour-to-colorectal signal ratios were 5.03 ± 0.37, 15.45 ± 0.32, 13.58 ± 1.19 and 11.33 ± 1.73 1, 2, 4 and 6 h after tail-veil injection, respectively. Overall, in the wake of rapid and precise tumour delineation and penetration characteristics, icatibant-based probes represent promising high-contrast molecular imaging probes for the detection of bradykinin B2R.

Comparison of Five Near-Infrared Fluorescent Folate Conjugates in an Ovarian Cancer Model

PURPOSE

Fluorescence imaging (FLI) using targeted near-infrared (NIR) conjugates aids the detection of tumour lesions pre- and intraoperatively. The optimisation of tumour visualisation and contrast is essential and can be achieved through high tumour-specificity and low background signal. However, the choice of fluorophore is recognised to alter biodistribution and clearance of conjugates and is therefore a determining factor in the specificity of target binding. Although ZW800-1, IRDye® 800CW and ICG are the most commonly employed NIR fluorophores in clinical settings, the fluorophore with optimal in vivo characteristics has yet to be determined. Therefore, we aimed to characterise the impact the choice of fluorophore has on the biodistribution, specificity and contrast, by comparing five different NIR fluorophores conjugated to folate, in an ovarian cancer model.

PROCEDURES

ZW800-1, ZW800-1 Forte, IRDye® 800CW, ICG-OSu and an in-house synthesised Cy7 derivative were conjugated to folate through an ethylenediamine linker resulting in conjugates 1-5, respectively. The optical properties of all conjugates were determined by spectroscopy, the specificity was assessed in vitro by flow cytometry and FLI, and the biodistribution was studied in vivo and ex vivo in a subcutaneous Skov-3 ovarian cancer model.

RESULTS

We demonstrated time- and receptor-dependent binding of folate conjugates in vitro and in vivo. Healthy tissue clearance characteristics and tumour-specific signal varied between conjugates 1-5. ZW800-1 Forte (2) revealed the highest contrast in folate receptor alpha (FRα)-positive xenografts and showed statistically significant target specificity. While conjugates 1, 2 and 3 are renally cleared, hepatobiliary excretion and no or very low accumulation in tumours was observed for 4 and 5.

CONCLUSIONS

The choice of fluorophore has a significant impact on the biodistribution and tumour contrast. ZW800-1 Forte (2) exhibited the best properties of those tested, with significant specific fluorescence signal.

Cysteine Cathepsins in Breast Cancer: Promising Targets for Fluorescence-Guided Surgery

The majority of breast cancer patients is treated with breast-conserving surgery (BCS) combined with adjuvant radiation therapy. Up to 40% of patients has a tumor-positive resection margin after BCS, which necessitates re-resection or additional boost radiation. Cathepsin-targeted near-infrared fluorescence imaging during BCS could be used to detect residual cancer in the surgical cavity and guide additional resection, thereby preventing tumor-positive resection margins and associated mutilating treatments. The cysteine cathepsins are a family of proteases that play a major role in normal cellular physiology and neoplastic transformation. In breast cancer, the increased enzymatic activity and aberrant localization of many of the cysteine cathepsins drive tumor progression, proliferation, invasion, and metastasis. The upregulation of cysteine cathepsins in breast cancer cells indicates their potential as a target for intraoperative fluorescence imaging. This review provides a summary of the current knowledge on the role and expression of the most important cysteine cathepsins in breast cancer to better understand their potential as a target for fluorescence-guided surgery (FGS). In addition, it gives an overview of the cathepsin-targeted fluorescent probes that have been investigated preclinically and in breast cancer patients. The current review underscores that cysteine cathepsins are highly suitable molecular targets for FGS because of favorable expression and activity patterns in virtually all breast cancer subtypes. This is confirmed by cathepsin-targeted fluorescent probes that have been shown to facilitate in vivo breast cancer visualization and tumor resection in mouse models and breast cancer patients. These findings indicate that cathepsin-targeted FGS has potential to improve treatment outcomes in breast cancer patients.

Data-Driven Identification of Targets for Fluorescence-Guided Surgery in Non-Small Cell Lung Cancer

PURPOSE

Intraoperative identification of lung tumors can be challenging. Tumor-targeted fluorescence-guided surgery can provide surgeons with a tool for real-time intraoperative tumor detection. This study evaluated cell surface biomarkers, partially selected via data-driven selection software, as potential targets for fluorescence-guided surgery in non-small cell lung cancers: adenocarcinomas (ADC), adenocarcinomas in situ (AIS), and squamous cell carcinomas (SCC).

PROCEDURES

Formalin-fixed paraffin-embedded tissue slides of resection specimens from 15 patients with ADC and 15 patients with SCC were used and compared to healthy tissue. Molecular targets were selected based on two strategies: (1) a data-driven selection using > 275 multi-omics databases, literature, and experimental evidence; and (2) the availability of a fluorescent targeting ligand in advanced stages of clinical development. The selected targets were carbonic anhydrase 9 (CAIX), collagen type XVII alpha 1 chain (collagen XVII), glucose transporter 1 (GLUT1), G protein-coupled receptor 87 (GPR87), transmembrane protease serine 4 (TMPRSS4), carcinoembryonic antigen (CEA), epithelial cell adhesion molecule (EpCAM), folate receptor alpha (FRα), integrin αvβ6 (αvβ6), and urokinase-type plasminogen activator receptor (uPAR). Tumor expression of these targets was assessed by immunohistochemical staining. A total immunostaining score (TIS, range 0-12), combining the percentage and intensity of stained cells, was calculated. The most promising targets in ADC were explored in six AIS tissue slides to explore its potential in non-palpable lesions.

RESULTS

Statistically significant differences in TIS between healthy lung and tumor tissue for ADC samples were found for CEA, EpCAM, FRα, αvβ6, CAIX, collagen XVII, GLUT-1, and TMPRSS4, and of these, CEA, CAIX, and collagen XVII were also found in AIS. For SCC, EpCAM, uPAR, CAIX, collagen XVII, and GLUT-1 were found to be overexpressed.

CONCLUSIONS

EpCAM, CAIX, and Collagen XVII were identified using concomitant use of data-driven selection software and clinical evidence as promising targets for intraoperative fluorescence imaging for both major subtypes of non-small cell lung carcinomas.

Preclinical Development and Validation of ASP5354: A Near-Infrared Fluorescent Agent for Intraoperative Ureter Visualization

PURPOSE

Iatrogenic ureteral injury (IUI) can complicate minimally invasive and open abdominopelvic surgery. The incidence of IUI is low and dependent on the type of surgery (< 10 %), but it is associated with high morbidity. Therefore, intraoperative visualization of the ureter is critical to reduce the incidence of IUI, and some methodologies for ureter visualization have been developed. Amongst these, near-infrared fluorescence (NIRF) visualization is thought to bring an advantage with real-time retroperitoneal visualization through the retroperitoneum. We investigated an indocyanine green (ICG) derivative, ASP5354, which emits NIRF at 820 nm when exposed to near-infrared light at a wavelength of 780 nm, in a rodent and porcine model.

PROCEDURES

Wistar rats and Göttingen minipigs under anesthesia were laparotomized and then administered ASP5354 chloride intravenously at dose of 0.03 and 0.3 mg/kg for rats and 0.001 and 0.01 mg/kg for minipigs, respectively. Videos of the abdominal cavity in minipigs were taken using a near-infrared fluorescent camera (pde-neo) and assessed visually by three independent clinicians. Toxicological evaluation was demonstrated with cynomolgus monkeys.

RESULTS

The proportion of animals whose ureters were visible up to 3 h after administration of ASP5354 chloride were 33 % at 0.001 mg/kg and 100 % at 0.01 mg/kg, respectively. In a toxicological study in cynomolgus monkeys, ASP5354 chloride demonstrated no significant toxicity, suggesting that 0.01 mg/kg provides an optimal dose when used clinically and could allow for ureter visualization during routine surgical procedures.

CONCLUSIONS

The dose of 0.01 mg/kg provided an optimal dose for ureter visualization up to 3 h after administration. ASP5354 shows promise for ureter visualization during abdominopelvic surgery, which may potentially lower the risk of IUI.

Quantitative perfusion assessment using indocyanine green during surgery - current applications and recommendations for future use

PURPOSE

Incorrect assessment of tissue perfusion carries a significant risk of complications in surgery. The use of near-infrared (NIR) fluorescence imaging with Indocyanine Green (ICG) presents a possible solution. However, only through quantification of the fluorescence signal can an objective and reproducible evaluation of tissue perfusion be obtained. This narrative review aims to provide an overview of the available quantification methods for perfusion assessment using ICG NIR fluorescence imaging and to present an overview of current clinically utilized software implementations.

METHODS

PubMed was searched for clinical studies on the quantification of ICG NIR fluorescence imaging to assess tissue perfusion. Data on the utilized camera systems and performed methods of quantification were collected.

RESULTS

Eleven software programs for quantifying tissue perfusion using ICG NIR fluorescence imaging were identified. Five of the 11 programs have been described in three or more clinical studies, including Flow® 800, ROIs Software, IC Calc, SPY-Q™, and the Quest Research Framework®. In addition, applying normalization to fluorescence intensity analysis was described for two software programs.

CONCLUSION

Several systems or software solutions provide a quantification of ICG fluorescence; however, intraoperative applications are scarce and quantification methods vary abundantly. In the widespread search for reliable quantification of perfusion with ICG NIR fluorescence imaging, standardization of quantification methods and data acquisition is essential.

Indocyanine green fluorescence imaging during laparoscopic rectal cancer surgery could reduce the incidence of anastomotic leakage: a single institutional retrospective cohort study

BACKGROUND

There is insufficient evidence on whether indocyanine green (ICG) fluorescence angiography can reduce the incidence of anastomotic leakage (AL). This retrospective cohort study aimed to evaluate the effect of ICG fluorescence angiography on AL rates in laparoscopic rectal cancer surgery at a single institution.

METHODS

Patients who underwent laparoscopic low anterior resection or intersphincteric resection with ICG fluorescence angiography (ICG group; n = 73) and patients who underwent a similar surgical procedure for rectal cancer without ICG fluorescence (non-ICG group; n = 114) were enrolled consecutively in this study. ICG fluorescence angiography was performed prior to transection of the proximal colon, and anastomosis was performed with sufficient perfusion using ICG fluorescence imaging. AL incidence was compared between both groups, and the risk factors for AL were analyzed.

RESULTS

AL occurred in 3 (4.1%) and 14 (12.3%) patients in the ICG and non-ICG groups, respectively. In the ICG group, the median perfusion time from ICG injection was 34 s, and 5 patients (6.8%) required revision of the proximal transection line. None of the patients requiring revision of the proximal transection line developed AL. In univariate analysis, longer operating time (odds ratio: 2.758; 95% confidence interval: 1.023-7.624) and no implementation of ICG fluorescence angiography (odds ratio: 3.266; 95% confidence interval: 1.038-11.793) were significant factors associated with AL incidence, although the creation of a diverting stoma or insertion of a transanal tube was insignificant.

CONCLUSION

ICG fluorescence angiography was associated with a significant reduction in AL during laparoscopic rectal cancer surgery. Changes in the surgical plan due to ICG fluorescence visibility may help improve the short-term outcomes of patients with rectal cancer.

Functional insights from targeted imaging BACE1: the first near-infrared fluorescent probe for Alzheimer's disease diagnosis

BACKGROUND

β-Secretase (BACE1) is the vital enzyme in the pathogenic processes of Alzheimer's disease (AD). However, the development of a powerful tool with sensitivity for BACE1 determination in vivo is a challenge.

METHODS

A novel NIR fluorescent probe HBAE was synthetized from 2-hydroxy-3-methylbenzaldehyde and 2-amino-benzenethiol by 5 steps. The fluorescence mechanism in the ESIPT systems of HBAE probe was insighted with time-dependent density functional theory (TD-DFT) at the TDPBE0 level with the def2-TZVP approach. The corresponding docking between HBAE and BACE1 (PDB: 5I3Y) was performed through the ducking method by DOCK6.8. Then the BBB permeability of HBAE is verified by transwell orifice plate. 22-month-old male AD-model (5XFAD) mice and age-matched wild-type mice were employed to observe the brain kinetics by intravenous injection. Finally, Immunohistochemistry was performed on the AD brain section to reveal the levels of BACE1 in hippocampus and cortex areas and other regions in AD mice through the brain tissue slices by HBAE.

RESULTS

The NIR fluorescent probe HBAE was successfully applied in imaging BACE1 in AD model mice. The capability of HBAE in reflecting different level of BACE1 was performed by the specific imaging of the hippocampus region.

CONCLUSIONS

We reported the first ESIPT near-infrared fluorescence probe HBAE for monitoring endogenous BACE1 in the AD live model mice, thus offering a versatile chemical tool for visualizing in the pathological processes of AD live brains. Remarkably, high resolution images showed the localization of red fluorescence stains in hippocampus of the AD brain. This study provides a promising way for functional insights from protein BACE1 in vivo.

Multifunctional nanotheranostics for near infrared optical imaging-guided treatment of brain tumors

Malignant brain tumors, a heterogeneous group of primary and metastatic neoplasms in the central nervous system (CNS), are notorious for their highly invasive and devastating characteristics, dismal prognosis and low survival rate. Recently, near-infrared (NIR) optical imaging modalities including fluorescence imaging (FLI) and photoacoustic imaging (PAI) have displayed bright prospect in innovation of brain tumor diagnoses, due to their merits, like noninvasiveness, high spatiotemporal resolution, good sensitivity and large penetration depth. Importantly, these imaging techniques have been widely used to vividly guide diverse brain tumor therapies in a real-time manner with high accuracy and efficiency. Herein, we provide a systematic summary of the state-of-the-art NIR contrast agents (CAs) for brain tumors single-modal imaging (e.g., FLI and PAI), dual-modal imaging (e.g., FLI/PAI, FLI/magnetic resonance imaging (MRI) and PAI/MRI) and triple-modal imaging (e.g., MRI/FLI/PAI and MRI/PAI/computed tomography (CT) imaging). In addition, we update the most recent progress on the NIR optical imaging-guided therapies, like single-modal (e.g., photothermal therapy (PTT), chemotherapy, surgery, photodynamic therapy (PDT), gene therapy and gas therapy), dual-modal (e.g., PTT/chemotherapy, PTT/surgery, PTT/PDT, PDT/chemotherapy, PTT/chemodynamic therapy (CDT) and PTT/gene therapy) and triple-modal (e.g., PTT/PDT/chemotherapy, PTT/PDT/surgery, PTT/PDT/gene therapy and PTT/gene/chemotherapy). Finally, we discuss the opportunities and challenges of the CAs and nanotheranostics for future clinic translation.

Indocyanine green fluorescence-guided surgery in head and neck cancer: A systematic review

OBJECTIVE

To assess the feasibility and effectiveness of indocyanine green (ICG) for image-guided resection of head and neck cancer (HNC).

DATA SOURCES

PubMed, Embase, and Scopus databases.

REVIEW METHODS

Searches were conducted from database inception to February 2022. Patient and study characteristics, imaging parameters, and imaging efficacy data were extracted from each study.

RESULTS

Nine studies met inclusion criteria, representing 103 head and neck tumors. Weighted mean ICG dose and imaging time were 1.27 mg/kg and 11.77 h, respectively. Among the five studies that provided quantitative metrics of imaging efficacy, average ICG tumor-to-background ratio (TBR) was 1.56 and weighted mean ONM-100 TBR was 3.64. Pooled sensitivity and specificity across the five studies were 91.7 % and 71.9 %, respectively.

CONCLUSION

FGS with ICG may facilitate real-time tumor-margin delineation to improve margin clearance rates and progression-free survival. Future studies with validated, quantitative metrics of imaging success are necessary to further evaluate the prognostic benefit of these techniques.

[Application of near infrared fluorescence imaging in detection of residual cancer in oral squamous cell carcinoma]

Objective: Local recurrence is the main cause of treatment failure in patients with oral squamous cell carcinoma (OSCC). This study was proposed to investigate the feasibility of near infrared fluorescence (NIF) via indocyanine green (ICG) for monitoring surgical marginal in operation for OSCC patients. Methods: In 35 patients with OSCC treated surgically in the Department of Oral and Maxillofacial Surgery, Nanjing University School of Medicine, from January 2019 to June 2020, ICG (0.75 mg/kg) was administered intravenously via elbow vein at (12±1) hours before surgery, and NIF was performed intraoperatively on the surgical field and the cut edge of the surgically excised specimen, and fluorescence intensity was measured for OSCC tissue and normal oral mucosa, abnormal fluorescence signals were taken and subjected to rapid cryopathological examination. Correlation between NIF tumor boundary grading and pathological tumor boundary grading was analyzed by Spearman correlation analysis. Results: Clear ICG NIF was obtained for tumor lesions in all 35 patients, with a positive rate of 100%. The fluorescence intensity of OSCC tissue was (412.73±146.56) au, which was higher than that of normal oral mucosa tissue [(279.38±82.56) au, P<0.01]. Abnormal fluorescence signals were detected at the tumor bed and the cut edge of the surgical resection specimen in 4 patients, of which 2 cases were pathologically confirmed as cancer cell residue and 2 cases as inflammatory cell infiltration. The rate of positive detection of cut margins using ICG NIF technique in OSCC was 5.7% (2/35). Twenty of the 35 OSCC patients had grade 1, 11 of grade 2, and 4 of grade 3 tumor borders revealed by NIF of surgical resection specimens, which was positively correlated with pathological tumor border (r=0.809, P<0.001). Conclusions: ICG NIF technique can effectively detect the residual cancer cells at the incision margin, which is of great clinical value in reducing local recurrence of OSCC after surgery due to intraoperative cancer residue.

Host-guest interactions of indocyanine green with β-cyclodextrin permit real-time characterization of the rat lymphatic system

Objective

Fluorescence contrast technology using indocyanine green (ICG) could be useful for the rapid, dynamic, and objective assessment of blood vessels and the surrounding tissues when combined with near-infrared (NIR) imaging. Although ICG is a clinically available NIR fluorescence imaging probe, it can easily aggregate and is, thus, unstable. In the present study, we examined the efficacy of a host–guest ICG–β-cyclodextrin (CD) complex, which is used in pharmaceutics to improve the water solubility, stability, and bioavailability of hydrophobic molecules, for NIR imaging after hind footpad administration in a rat model.

Methods

To verify the performance of the ICG-β-CD complex with the host–guest self-assembly method in vivo, we performed simultaneous small animal (IVIS Spectrum system; PerkinElmer, Waltham, MA) and clinical (DIGI-MIH-001 near-infrared fluorescence imaging system; Beijing Digital Precision Medical Technology Co, Ltd, Beijing, China) imaging and evaluated the fluorescent properties of the ICG-β-CD complex in the hind footpad model of Sprague-Dawley male rats.

Results

We successfully prepared the ICG-β-CD complex. Compared with ICG, in vivo experiments showed that this complex had reduced absorbance at 710 nm and increased absorbance at 780 nm, indicating that it could prevent the dimeric aggregation of ICG, and a significantly higher fluorescence intensity at 730 nm excitation. After injection of 1.25 mg/mL of ICG or ICG-β-CD complex solutions into the rat hind footpad, fluorescent NIR lymphatic images were observed with both imaging systems. During the 12-hour observation period, the signal background ratio of ICG-β-CD showed a greater acute increase and a higher signal background ratio compared with ICG. The signal background ratio of ICG-β-CD was 125 to 100 from 260 to 540 minutes. These in vivo data suggest that ICG-β-CD has greater diffusion from the injection site and faster transport to the lymphatic system compared with ICG.

Conclusions

ICG-β-CD showed faster lymphatic transport than ICG, allowing for more rapid lymphatic NIR imaging. Thus, the ICG-β-CD complex might be a promising fluorescent agent for clinical lymphatic NIR imaging.

The lymphatic system plays a crucial role in maintaining tissue fluid homeostasis by draining protein-rich fluid from the perivascular interstitial spaces back into the circulation. The lymphatic system also plays a variety of roles in the progression of some peripheral vascular diseases, including venous leg ulcers, atherosclerotic vascular disease, and severe foot infection. Understanding the dynamic changes of the lymphatic fluid is indispensable for a variety of clinical situations and research areas. We investigated the potential feasibility of the indocyanine green–β-cyclodextrin complex in clinical applications using clinically available near-infrared fluorescence imaging equipment.

Intraoperative near-infrared fluorescence imaging can identify pelvic nerves in patients with cervical cancer in real time during radical hysterectomy

Purpose

Radical hysterectomy combined with pelvic lymphadenectomy is the standard treatment for early-stage cervical cancer, but unrecognized pelvic nerves are vulnerable to irreversible damage during surgery. This early clinical trial investigated the feasibility and safety of intraoperative near-infrared (NIR) fluorescence imaging (NIR-FI) with indocyanine green (ICG) for identifying pelvic nerves during radical hysterectomy for cervical cancer.

Methods

Sixty-six adults with cervical cancer were enrolled in this prospective, open-label, single-arm, single-center clinical trial. NIR-FI was performed in vivo to identify genitofemoral (GN), obturator (ON), and hypogastric (HN) nerves intraoperatively. The primary endpoint was the presence of fluorescence in pelvic nerves. Secondary endpoints were the ICG distribution in a nerve specimen and potential underlying causes of fluorescence emission in pelvic nerves.

Results

In total, 63 patients were analyzed. The ON was visualized bilaterally in 100% (63/63) of patients, with a mean fluorescence signal-to-background ratio (SBR) of 5.3±2.1. The GN was identified bilaterally in 93.7% (59/63) of patients and unilaterally in the remaining 4 patients, with a mean SBR of 4.1±1.9. The HN was identified bilaterally in 81.0% (51/63) of patients and unilaterally in 7.9% (5/63) of patients, with a mean SBR of 3.5±1.3. ICG fluorescence was detected in frozen sections of a nerve specimen, and was mainly distributed in axons. No ICG-related complications were observed.

Conclusion

This early clinical trial demonstrated the feasibility and safety of NIR-FI to visualize pelvic nerves intraoperatively. Thus, NIR-FI may help surgeons adjust surgical decision-making, avoid nerve damage, and improve surgical outcomes.

Trial registration

ClinicalTrials.gov NCT04224467

Near-infrared fluorescence imaging with indocyanine green for assessment of donor livers in a rat model of ischemia-reperfusion

BACKGROUND

Although marginal donor livers expand the donor pool, an ideal method for quantitatively evaluating the quality of donor livers has not been developed. This study aimed to explore the feasibility of indocyanine green (ICG) fluorescence imaging for estimating liver function in an ischemia-reperfusion model.

METHODS

Forty-eight rats were randomly and evenly divided into 8 groups: the control group and the experimental groups (I-VII). The portal vein blocking period was 0 min, 10 min, 20 min, 30 min, 40 min, 50 min and 60 min. After blood flow was reestablished and the hemodynamics stabilized, ICG was injected through the dorsal penile vein as a bolus, and the fluorescence signal was recorded for 30 min in real time. The fluorescence intensity (FI) curve of the liver was fitted with an asymptotic regression model. Fresh liver tissues and serum were obtained from the middle lobe of the liver on postoperative day (POD) 1 and POD 7 for histopathological evaluation and liver function tests.

RESULTS

The growth rate of the FI curve, parameter b3, decreased from groups I to VII. According to the two sudden changes in b3 (20 min, 50 min), the experimental groups could be classified into 3 groups (A, B and C). Hepatocytes in groups I-II showed slight edema, group III began to show obvious hepatocyte edema and vacuolar degeneration, and in groups VI-VII, severe hepatocyte degeneration, necrosis and large inflammatory cell infiltration were observed. Suzuki's scores in the 3 groups were also significantly different (P < 0.01). At the same time, the serum liver function in the experimental groups showed a significant increase on POD 1 and a decrease on POD 7. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TB) levels of groups A, B, and C were significantly different on POD 1 (P < 0.05), and the ALT and direct bilirubin (DB) levels were significantly different on POD 7 (P < 0.05); the lactic dehydrogenase (LDH) level of the group C was significantly higher than that of the groups A and B on POD 1 and POD 7. Meanwhile, the 7-day survival rate of the rats in group C was poor compared to that of the rats in groups A and B (58.3% vs. 100% vs. 100%).

CONCLUSION

ICG fluorescence imaging is effective for estimating the degree of liver damage and grading in an ischemia-reperfusion model. It probably has the potential for use in assessing the quality of the donor liver in liver transplantation.

Intra-operative assessment of the vascularisation of a cross section of the meniscus using near-infrared fluorescence imaging

PURPOSE

The purpose of this study was to assess whether the vascularisation of the meniscus could be visualised intra-operatively using near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) in patients undergoing total knee arthroplasty (TKA).

METHODS

The anterior horn (i.e., Cooper classification: zones C and D) of the meniscus that was least affected (i.e., least degenerative) was removed during TKA surgery in ten patients to obtain a cross section of the inside of the meniscus. Thereafter, 10 mg of ICG was injected intravenously, and vascularisation of the cross section of the meniscus was assessed using the Quest spectrum NIRF camera system. We calculated the percentage of patients in whom vascularisation was observed intra-operatively using NIRF imaging compared to immunohistochemistry.

RESULTS

Meniscal vascularisation using NIRF imaging was observed in six out of eight (75%) patients in whom vascularisation was demonstrated with immunohistochemistry. The median extent of vascularisation was 13% (interquartile range (IQR) 3-28%) using NIRF imaging and 15% (IQR 11-23%) using immunohistochemistry.

CONCLUSION

This study shows the potential of NIRF imaging to visualise vascularisation of the meniscus, as vascularisation was observed in six out of eight patients with histologically proven meniscal vascularisation.

LEVEL OF EVIDENCE

IV.

Monodisperse ZIF-8@dextran nanoparticles co-loaded with hydrophilic and hydrophobic functional cargos for combined near-infrared fluorescence imaging and photothermal therapy

Impressive developments have been achieved with the use of zeolitic imidazolate framework-8 (ZIF-8) as nanocarriers for tumor theranostics in recent decades by incorporating imaging agents and therapeutic drugs within ZIF-8. However, the simultaneous immobilization of hydrophilic and hydrophobic functional molecules into ZIF-8 nanoparticles in water or organic solvents still presents a daunting challenge. Herein, we developed a new synthesis/encapsulation two-in-one (denoted as one-pot) approach to synthesize uniform dextran-modified Cy5.5&ICG@ZIF-8-Dex nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) during the same step. It was confirmed that the one-pot approach in this mixed solvents facilitated the loading of ICG and Cy5.5 molecules. Moreover, the encapsulation of Cy5.5 and ICG within ZIF-8 nanoparticles endowed them with fluorescence imaging capability and photothermal conversion capacity, respectively. The in vivo near-infrared (NIR) fluorescent images of A549-bearing mice injected with Cy5.5&ICG@ZIF-8-Dex demonstrated sufficient accumulations of Cy5.5 at tumor sites due to the enhanced permeability and retention effect. Most impressively, the fluorescent intensity of Cy5.5&ICG@ZIF-8-Dex at tumor site was approximately 40-fold higher than that of free Cy5.5. Additionally, the results of in vivo infrared imaging and photothermal therapy of Cy5.5&ICG@ZIF-8-Dex showed enhanced therapeutic efficiency in comparison with free ICG, further confirming its tumor-targeting capability and photothermal capacity. Therefore, this multifunctional system based on ZIF-8 nanocarriers offered a potential nanoplatform for tumor-targeting theranostics, thus broadening the synthesis and applications of ZIF-8 composite nanoparticles for NIR fluorescence imaging and photothermal therapy in the biomedical field. STATEMENT OF SIGNIFICANCE: Simultaneous immobilization of hydrophilic and hydrophobic molecules into ZIF-8 nanoparticles still remains a daunting challenge. Therefore, we have developed a new synthesis/encapsulation two-in-one approach to synthesize uniform Cy5.5&ICG@ZIF-8-Dex composite nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) functional molecules during a single step. The results showed that the co-loading of Cy5.5 and ICG within the ZIF-8 nanoparticles endowed them with a remarkable fluorescence imaging capability and photothermal conversion capacity. Based on their enhanced convenience and efficacy to simultaneously encapsulate hydrophilic and hydrophobic molecules, the multifunctional nanocarriers that were prepared in the DMSO/H₂O mixed solvents provide a potential nanoplatform toward fluorescence imaging and photothermal therapy for tumor theranostics.

Tracking macrophages in diabetic neuropathy with two-color nanoemulsions for near-infrared fluorescent imaging and microscopy

Background

The incidence of diabetes and diabetic peripheral neuropathy continues to rise, and studies have shown that macrophages play an important role in their pathogenesis. To date, macrophage tracking has largely been achieved using genetically-encoded fluorescent proteins. Here we present a novel two-color fluorescently labeled perfluorocarbon nanoemulsion (PFC-NE) designed to monitor phagocytic macrophages in diabetic neuropathy in vitro and in vivo using non-invasive near-infrared fluorescent (NIRF) imaging and fluorescence microscopy.

Methods

Presented PFC-NEs were formulated with perfluorocarbon oil surrounded by hydrocarbon shell carrying two fluorescent dyes and stabilized with non-ionic surfactants. In vitro assessment of nanoemulsions was performed by measuring fluorescent signal stability, colloidal stability, and macrophage uptake and subsequent viability. The two-color PFC-NE was administered to Lepr^db/db and wild-type mice by tail vein injection, and in vivo tracking of the nanoemulsion was performed using both NIRF imaging and confocal microscopy to assess its biodistribution within phagocytic macrophages along the peripheral sensory apparatus of the hindlimb.

Results

In vitro experiments show two-color PFC-NE demonstrated high fluorescent and colloidal stability, and that it was readily incorporated into RAW 264.7 macrophages. In vivo tracking revealed distribution of the two-color nanoemulsion to macrophages within most tissues of Lepr^db/db and wild-type mice which persisted for several weeks, however it did not cross the blood brain barrier. Reduced fluorescence was seen in sciatic nerves of both Lepr^db/db and wild-type mice, implying that the nanoemulsion may also have difficulty crossing an intact blood nerve barrier. Additionally, distribution of the nanoemulsion in Lepr^db/db mice was reduced in several tissues as compared to wild-type mice. This reduction in biodistribution appears to be caused by the increased number of adipose tissue macrophages in Lepr^db/db mice.

Conclusions

The nanoemulsion in this study has the ability to identify phagocytic macrophages in the Lepr^db/db model using both NIRF imaging and fluorescence microscopy. Presented nanoemulsions have the potential for carrying lipophilic drugs and/or fluorescent dyes, and target inflammatory macrophages in diabetes. Therefore, we foresee these agents becoming a useful tool in both imaging inflammation and providing potential treatment in diabetic peripheral neuropathy.

Fluorescence-based bowel anastomosis perfusion evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

Anastomotic leakage (AL) is one of the dreaded complications following surgery in the digestive tract. Near-infrared fluorescence (NIRF) imaging is a means to intraoperatively visualize anastomotic perfusion, facilitating fluorescence image-guided surgery (FIGS) with the purpose to reduce the incidence of AL. The aim of this study was to analyze the current practices and results of NIRF imaging of the anastomosis in digestive tract surgery through the EURO-FIGS registry.

METHODS

Analysis of data prospectively collected by the registry members provided patient and procedural data along with the ICG dose, timing, and consequences of NIRF imaging. Among the included upper-GI, colorectal, and bariatric surgeries, subgroup analysis was performed to identify risk factors associated with complications.

RESULTS

A total of 1240 patients were included in the study. The included patients, 74.8% of whom were operated on for cancer, originated from 8 European countries and 30 hospitals. A total of 54 surgeons performed the procedures. In 83.8% of cases, a pre-anastomotic ICG dose was administered, and in 60.1% of cases, a post-anastomotic ICG dose was administered. A significant difference (p < 0.001) was found in the ICG dose given in the four pathology groups registered (range: 0.013-0.89 mg/kg) and a significant (p < 0.001) negative correlation was found between the ICG dose and BMI. In 27.3% of the procedures, the choice of the anastomotic level was guided by means of NIRF imaging which means that in these cases NIRF imaging changed the level of anastomosis which was first decided based on visual findings in conventional white light imaging. In 98.7% of the procedures, the use of ICG partly or strongly provided a sense of confidence about the anastomosis. A total of 133 complications occurred, without any statistical significance in the incidence of complications in the anastomoses, whether they were ICG-guided or not.

CONCLUSION

The EURO-FIGS registry provides an insight into the current clinical practice across Europe with respect to NIRF imaging of anastomotic perfusion during digestive tract surgery.

A pilot study of near-infrared fluorescence guided surgery for primary tumor localization and lymph node mapping in colorectal cancer

Background

This pilot study aimed to evaluate the feasibility of near-infrared fluorescence imaging for primary tumor localization, lymph node mapping, and metastatic lymph node detection in colorectal cancer (CRC) using indocyanine green (ICG).

Methods

A total of 11 patients with CRC were prospectively enrolled. ICG (25 mg dissolved in 30 mL sterile water) was intravenously injected preoperatively, and the fluorescence intensity of the primary tumor, lymph nodes, and normal tissues, as well as the signal-to-background ratio (SBR) and contrast-to-noise ratio (CNR) were measured at 0.5, 1, 2, 4, and 24 h after ICG injection.

Results

The primary tumor could be located intraoperatively, and the tumor boundary was clear at 2–4 h. There was good contrast in the fluorescence intensity between tumor and normal tissues (SBR =2.11±0.36, CNR =8.74±0.35). The lymph node detection rate was 95% (38/40), and the SBR threshold of lymph nodes was 1.13.

Conclusions

This pilot study showed that primary tumor localization and lymph node mapping in CRC is feasible using near-infrared fluorescence imaging technology, though metastatic lymph nodes cannot be discriminated from benign ones. In addition, cancer nodules missed by both white light mode and palpation by the surgeon were unexpectedly found, resulting in a change in the surgical prognosis in 9.1% (1/11) of patients.

Near-infrared fluorescence imaging-guided lymphatic mapping in thoracic esophageal cancer surgery

PURPOSE

Identifying the lymphatic drainage pathway is important for accurate lymph node (LN) dissection in esophageal cancer (EC). This study aimed to assess lymphatic drainage mapping in thoracic EC using near-infrared fluorescent (NIRF) imaging with indocyanine green (ICG) and identify its feasibility for intraoperative LN drainage visualization and dissection.

METHODS

From November 2019 to August 2020, esophagectomy was performed using intraoperative NIRF navigation with ICG injected into the esophageal submucosa by endoscopy. All LNs were divided into four groups according to the NIRF status and presence of metastasis: NIRF⁺LN⁺, NIRF⁺LN^-, NIRF^-LN⁺, and NIRF^-LN^-.

RESULTS

Regional LNs were detected in all 84 enrolled patients with thoracic EC. A total of 2164 LNs were removed, and the mean number of dissected LNs was 25.68 ± 12.00. NIRF⁺ LNs were observed in all patients and distributed at 19 LN stations, which formed lymphatic drainage maps. The top five LN stations of NIRF⁺ probability in upper thoracic EC were No. 7, 106ecR, 107, 1, and 106recL; in middle thoracic EC, they were No. 107, 7, 110, 1, and 105; and in lower thoracic EC, they were No. 107, 7, 110, 106recR, and 1. There were no cases of ICG-related adverse events or chylothorax. The 30-day mortality rate was 0%. Major complications included anastomotic fistula (7.14%), pneumonia (4.76%), pleural effusion (13.10%), atelectasis (3.75%), hoarseness (8.33%), and arrhythmia (4.76%).

CONCLUSION

Regional LN mapping of thoracic EC was performed using ICG/NIRF imaging, which showed different preferred LN drainage stations in various anatomical locations of the thoracic esophagus. ICG/NIRF imaging is feasible for intraoperative LN drainage visualization and dissection.

CLINICAL TRIAL REGISTRATION

The clinical trial registration number is NCT04173676 ( http://www.clinicaltrials.gov/ ).

Relation Between Early Disturbance of lymphatic transport Visualized With Lymphofluoroscopy and Other Clinical Assessment Methods in Patients With Breast Cancer

INTRODUCTION

Lymphedema of the upper extremity is one of the most feared complications following breast cancer treatment. Lymphofluoroscopy is a sensitive instrument for detection of lymphedema and visualization of superficial lymphatic transport, thus suitable for early detection. Early detection of lymphedema is important as it can prevent lymphedema to progress into more severe stages and minimalize impact on quality of life and medical costs.

OBJECTIVE

To determine agreement between the presence of early disturbance of the lymphatic transport and outcome of clinical measurement tools evaluating the development of lymphedema.

METHODS

A prospective study was conducted in 128 breast cancer patients scheduled for breast cancer surgery. Patients were evaluated before surgery and 1, 3-, 6-, 9-, and 12-months' post-surgery. Cohen's Kappa was used to determine agreement between presence of early disturbance in lymphatic transport and presence of pitting/increased skinfold thickness/increased Percentage Water Content ratio (PWC)/increased arm-hand volume (circumference measures and water displacement).

RESULTS

For pitting status (Kappa 0.23), for skinfold thickness (Kappa 0.29) and the PWC ratio (Kappa 0.21) a minimal agreement was found. The circumference measurement had a minimal agreement for 5% volume difference (Kappa 0.22) and no agreement for 3% volume difference (Kappa 0.19). Sensitivity was weak for all clinical assessments. The specificity was excellent for pitting status, skinfold thickness, PWC ratio, and for 5% volume difference. For 3% a high specificity was found.

CONCLUSION

The clinical tools assessed in this study were not able to predict an early disturbance of the lymphatic transport seen on lymphofluoroscopy.

Effect of Formalin Fixation for Near-Infrared Fluorescence Imaging with an Antibody-Dye Conjugate in Head and Neck Cancer Patients

PURPOSE

This study evaluated the effect of formalin fixation for near-infrared (NIR) fluorescence imaging of an antibody-dye complex (panitumumab-IRDye800CW) that was intravenously administered to patients with head and neck squamous cell carcinoma (HNSCC) scheduled to undergo surgery of curative intent.

PROCEDURES

HNSCC patients were infused with 25 or 50 mg of panitumumab-IRDye800CW followed by surgery 1-5 days later. Following resection, primary tumor specimens were imaged in a closed-field fluorescence imaging device, before and after formalin fixation. The fluorescence images of formalin-fixed specimens were compared with images prior to formalin fixation. Regions of interest were drawn on the primary tumor and on the adjacent normal tissue on the fluorescence images. The mean fluorescence intensity (MFI) and tumor-to-background ratios (TBRs) of the fresh and formalin-fixed tissues were compared.

RESULTS

Of the 30 enrolled patients, 20 tissue specimens were eligible for this study. Formalin fixation led to an average of 10 % shrinkage in tumor specimen size (p < 0.0001). Tumor MFI in formalin-fixed specimens was on average 10.9 % lower than that in the fresh specimens (p = 0.0002). However, no statistical difference was found between the TBRs of the fresh specimens and those of the formalin-fixed specimens (p = 0.85).

CONCLUSIONS

Despite the 11 % decrease in MFI between fresh and formalin-fixed tissue specimens, the relative difference between tumor and normal tissue as measured in TBR remained unchanged. This data suggests that evaluation of formalin-fixed tissue for assessing the accuracy of fluorescence-guided surgery approaches could provide a valid, yet more flexible, alternative to fresh tissue analysis.

TRIAL REGISTRATION

NCT02415881.

Oral absorption mechanism of the polysaccharides from Gastrodia elata Blume base on fluorescence labeling

The mechanisms of action of polysaccharides in vivo have been widely elucidated. However, the systematic research of its absorption and transport mechanisms remains unclear. Herein, we extracted a polysaccharide fraction (GEP) from Gastrodia elata by water extraction and alcohol precipitation and aimed to reveal its oral absorption processes through animal models and Caco-2 cells monolayer models. Our research data showed that GEP-Cy5.5 could be absorbed through the small intestine and the main absorption intestinal segment was the ileum (the absorption rate constant [Ka]: (3.64 ± 0.70) × 10^-4 cm/s; the effective apparent permeability [Papp value]: (4.88 ± 1.02) × 10^-5 cm/s). The ligated intestinal loops also revealed that GEP-Cy5.5 could pass through the villi of the small intestine and the mucosal barrier into the submucosa. Furthermore, GEP-Cy5.5 was readily absorbed into the blood through the gastrointestinal tract, then distributed in the liver and the kidney. The Papp value of in vitro transport study was (1.29 ± 0.08) × 10^-6 cm/s, which was a time-dependent process. Notably, GEP-Cy5.5 was transported through the endocytosis process mediated by clathrin and macropinocytosis. The underlying absorptive mechanisms of GEP in vivo and in vitro were clarified, which provided the guidance for clinical medicine administration and could deepen the biological understanding of oral polysaccharides.

Pre-clinical study of IRDye800CW-nimotuzumab formulation, stability, pharmacokinetics, and safety

Background

Epidermal growth factor receptor (EGFR) is a target for cancer therapy as it is overexpressed in a wide variety of cancers. Therapeutic antibodies that bind EGFR are being evaluated in clinical trials as imaging agents for positron emission tomography and image-guided surgery. However, some of these antibodies have safety concerns such as infusion reactions, limiting their use in imaging applications. Nimotuzumab is a therapeutic monoclonal antibody that is specific for EGFR and has been used as a therapy in a number of countries.

Methods

Formulation of IRDye800CW-nimotuzumab for a clinical trial application was prepared. The physical, chemical, and pharmaceutical properties were tested to develop the specifications to determine stability of the product. The acute and delayed toxicities were tested and IRDye800CW-nimotuzumab was determined to be non-toxic. Non-compartmental pharmacokinetics analysis was used to determine the half-life of IRDye800CW-nimotuzumab.

Results

IRDye800CW-nimotuzumab was determined to be non-toxic from the acute and delayed toxicity study. The half-life of IRDye800CW-nimotuzumab was determined to be 38 ± 1.5 h. A bi-exponential analysis was also used which gave a t_1/2 alpha of 1.5 h and t_1/2 beta of 40.8 h.

Conclusions

Here, we show preclinical studies demonstrating that nimotuzumab conjugated to IRDye800CW is safe and does not exhibit toxicities commonly associated with EGFR targeting antibodies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08003-3.

Self-assembled heptamethine cyanine dye dimer as a novel theranostic drug delivery carrier for effective image-guided chemo-photothermal cancer therapy

Near-infrared (NIR)-induced dye-based theranostic drug delivery carriers are used for critical image-guided chemo-photothermal cancer therapy. However, most carriers fail to deliver sufficient heat and fluorescence efficiently due to direct π-π stacking of the aromatic rings of the NIR dye and drug. In the work reported herein, we examined a self-assembled heptamethine cyanine dye dimer (CyD) with improved heat and fluorescence delivery that was developed by manipulating the unique structural and optical properties of the dimer. The H-aggregation of CyD in an aqueous solution generated a great amount of heat by transforming the energy of the excited electrons into non-radiative energy. Moreover, the disulfide bond of CyD assisted nanoparticles with a drug by minimizing the interaction between the NIR dye and drug, and also by releasing the drug in a redox environment. As a result, DOX encapsulated within CyD (CyD/DOX) showed strong heat generation and fluorescence imaging in tumor-bearing mice, allowing detection of the tumor site and inhibition of tumor growth by chemo-photothermal therapy. The multiplicity of features supplied by the newly developed CyD demonstrated the potential of CyD/DOX as an NIR dye-based theranostic drug-delivery carrier for effective chemo-photothermal cancer therapy.

Magnetic mesoporous silica nanoparticles-aided dual MR/NIRF imaging to identify macrophage enrichment in atherosclerotic plaques

Active foamy macrophage enrichment drives atherosclerotic plaque initiation and evolution, and is the prominent target for precisely identifying vulnerable plaque. Precise imaging of high-risk plaque allows promotion of treatment and prevention of vascular pathema. However, current iron oxide (IO) nanoparticles-based magnetic resonance (MR) imaging of plaque is often limited by insufficient perfusion and nonspecific accumulation of peri-aortic lymph nodes. Besides that, intrinsic defects of MR also impede its use for accurately identifying plaque details. Herein, by conjugating with PP1 peptide, a novel magnetic mesoporous silica nanoparticle (PIMI) loaded with near-infrared fluorescence (NIRF) dye (IR820) was fabricated to specifically target and quantify macrophage enrichment of atherosclerotic plaque in ApoE^-/- mice using dual MR/NIRF imaging. Biocompatibility experiments ulteriorly confirmed the high safety of PIMI nanoparticles in vivo, which lays the foundation of next-generation contrast agent for recognizing macrophage-rich plaque in the near future.

Near-infrared fluorescence imaging compared to standard sentinel lymph node detection with blue dye in patients with vulvar cancer - a randomized controlled trial

OBJECTIVE

The aim of this study was to assess the superiority of ICG-^99mTc-nanocolloid for the intraoperative visual detection of sentinel lymph nodes (SLNs) in vulvar squamous cell carcinoma (VSCC) patients compared to standard SLN detection using ^99mTc-nanocolloid with blue dye.

METHODS

In this multicenter, randomized controlled trial, VSCC patients underwent either the standard SLN procedure or with the hybrid tracer ICG-^99mTc-nanocolloid. The primary endpoint was the percentage of fluorescent SLNs compared to blue SLNs. Secondary endpoints were successful SLN procedures, surgical outcomes and postoperative complications.

RESULTS

Forty-eight patients were randomized to the standard (n = 24) or fluorescence imaging group (n = 24) using ICG-^99mTc-nanocolloid. The percentage of blue SLNs was 65.3% compared to 92.5% fluorescent SLNs (p < 0.001). A successful SLN procedure was obtained in 92.1% of the groins in the standard group and 97.2% of the groins in the fluorescence imaging group (p = 0.33). Groups did not differ in surgical outcome, although more short-term postoperative complications were documented in the standard group (p = 0.041).

CONCLUSIONS

Intraoperative visual detection of SLNs in patients with VSCC using ICG-^99mTc-nanocolloid was superior compared to ^99mTc-nanocolloid and blue dye. The rate of successful SLN procedures between both groups was not significantly different. Fluorescence imaging has potential to be used routinely in the SLN procedure in VSCC patients to facilitate the search by direct visualization.

CLINICAL TRIAL REGISTRATION

Netherlands Trial Register (Trial ID NL7443).

Near-Infrared Fluorescence Imaging in the Identification of Parathyroid Glands in Thyroidectomy

OBJECTIVES/HYPOTHESIS

To assess the ability of near-infrared fluorescence imaging (NIFI) to identify parathyroid glands (PGs) among histologically proven PG/non-PG specimens compared with a surgeon's visual acumen, and to determine NIFI sensitivity in detecting incidentally resected PGs from thyroidectomy specimens, compared to the surgeon's visual inspection.

STUDY DESIGN

Prospective study.

METHODS

With mean age of 61 years, 36 patients with various thyroid diseases were enrolled. Possible PGs (n = 28) and lymph nodes (n = 32) were identified by the experienced surgeon's visual inspection. Using NIFI, 15 PGs were further identified from thyroidectomy specimens. For these 75 specimens, the surgeon's judgments (PG vs. non-PG) were recorded. Histological evaluation was performed after examining the NIFI auto-fluorescence of each specimen.

RESULTS

There were no significant differences in sensitivity, specificity, positive predictive value, and negative predictive value between the surgeon's visual inspection and NIFI in identifying PGs, with values of 100%/97.1%, 85.0%/87.5%, 85.4%/87.2%, and 100%/97.2%, respectively. The sensitivity of NIFI (82.9%) for detection of PGs from thyroidectomy specimens was significantly higher than that of the surgeon's visual inspection (61.0%). False negative specimens contained bleeding/congestion and/or encapsulation by thick tissues, whereas false positive specimens contained electrocoagulated tissues.

CONCLUSIONS

NIFI showed results comparable to the experienced surgeon's visual inspection in identifying PGs. This could benefit novice surgeons. NIFI may be useful for experienced surgeons to locate incidentally resected PGs within thyroidectomy specimens for auto-transplantation. Prevention of intra-gland bleeding and congestion, careful removal of thick capsules, and bloodless surgeries without electrocoagulation are important for reducing false positive and false negative results. Laryngoscope, 131:1188-1193, 2021.

Sentinel lymph node mapping using ICG fluorescence and cone beam CT - a feasibility study in a rabbit model of oral cancer

BACKGROUND

Current sentinel lymph node biopsy (SLNB) techniques, including use of radioisotopes, have disadvantages including the use of a radioactive tracer. Indocyanine green (ICG) based near-infrared (NIR) fluorescence imaging and cone beam CT (CBCT) have advantages for intraoperative use. However, limited literature exists regarding their use in head and neck cancer SLNB.

METHODS

This was a prospective, non-randomized study using a rabbit oral cavity VX2 squamous cell carcinoma model (n = 10) which develops lymph node metastasis. Pre-operatively, images were acquired by MicroCT. During surgery, CBCT and NIR fluorescence imaging of ICG was used to map and guide the SLNB resection.

RESULTS

Intraoperative use of ICG to guide fluorescence resection resulted in identification of all lymph nodes identified by pre-operative CT. CBCT was useful for near real time intraoperative imaging and 3D reconstruction.

CONCLUSIONS

This pre-clinical study further demonstrates the technical feasibility, limitations and advantages of intraoperative NIR-guided ICG imaging for SLN identification as a complementary method during head and neck surgery.

Near-infrared fluorescence imaging-guided focused ultrasound-mediated therapy against Rheumatoid Arthritis by MTX-ICG-loaded iRGD-modified echogenic liposomes

Rheumatoid arthritis (RA), a common inflammatory disorder of the joints characterized by synovitis and pannus formation, often results in irreversible joint erosion and disability. Methotrexate (MTX) is the first-line drug against RA, but the therapeutic effects are sub-optimal due to its poor retention at the target sites and systemic side effects. Multifunctional nanoparticles are highly promising agents for minimally invasive, traceable and effective targeted therapy.

Methods: This study developed iRGD peptide-functionalized echogenic liposomes (iELPs) which encapsulates MTX and indocyanine green (ICG) fluorescent probe through the thin film-hydration method.

Results: The resulting iELPs showed high affinity for endothelial cells overexpressing αvβ3 integrin, favorable acoustic response and fluorescence tracking properties. Also, near-infrared (NIR) fluorescence imaging of iELPs and ultrasound-triggered drug release of MTX were proved in a mouse RA model, greatly improving the therapeutic efficacy and reducing MTX side effects. Histological assessment of the articular tissues further revealed significantly lower inflammatory cell infiltration and angiogenesis in the iELPs-treated and sonicated mice.

Conclusion: Our study provides a promising nanoplatform for integrating ultrasound-controlled drug release and NIR fluorescence imaging for RA treatment.

Upstaging nodal status in colorectal cancer using ex vivo fluorescence sentinel lymph node mapping: preliminary results

BACKGROUND

Sentinel lymph node (SLN) mapping using near-infrared fluorescence (NIRF) imaging is a recent technique to improve nodal staging in several tumors. The presence of colorectal cancer (CRC) micro-metastases has recently been defined as N1 disease and no longer as N1mi, determining the need for adjuvant chemotherapy. In CRC, the reported rate of SLN micro-metastases detected by ultrastaging techniques is as high as 30%. The aim of this prospective study is to report the preliminary results of the sensitivity analysis of NIRF imaging for ex vivo SLN mapping and the research of micro-metastases in CRC, in patients with node-negative disease (NND).

MATERIAL AND METHODS

On the specimen of 22 CRC patients, 1 mL of ICG (5 mg/mL) was injected submucosally around the tumor to identify SLNs. NND SLNs were further investigated with ultrastaging techniques.

RESULTS

Three-hundred and sixty-three lymph nodes were retrieved (59 SLNs; mean per case: 2.7). The detection, sensitivity and false-negative rate were 100%, 100% and 0% respectively. Ultrastaging investigations showed no micro-metastases in the NND SLNs.

CONCLUSIONS

The ex vivo SLN fluorescence-based detection in CRC was confirmed to be easy to perform and reliable. In this preliminary results report of an ongoing study, the SLN assay was congruent with the nodal status, as confirmed by histological investigations.

Perioperative and 1-year patient-reported outcomes of Freyer versus Millin versus Madigan robot-assisted simple prostatectomy

PURPOSE

Robotic-assisted simple prostatectomy (RASP) is an established surgical procedure for the management of obstructive symptoms caused by large adenomas. Traditionally, this is performed according to the trans-vescical (Freyer) or trans-capsular (Millin) technique. We recently described a novel urethra-sparing (Madigan) robotic technique which showed promising preliminary results. In this study, we compared the above techniques for perioperative and 1-year patient-reported outcomes.

METHODS

We retrospectively collected data from patients who underwent RASP across the three techniques, performed by two experienced surgeons in our center. We assessed patient self-reported pre-operative and post-operative functional outcomes with validated questionnaires: IPSS, IIEF short form, ICIQ short form, MSHQ Short Form. Continuous and categorical variables were compared between groups using the Mood's median test and the Chi-square tests, respectively.

RESULTS

Millin, Madigan and Freyer procedures were performed in 23 (51%), 14 (31%) and 8 (18%) cases, respectively. No significant differences were observed for baseline ASA score, BMI, prostate volume, IPSS, IIEF, ICIQ and MSHQ scores (all p ≥ 0.2), as well as post-operative obstructive symptoms relief (IPSS: p = 0.25), continence (ICIQ: p = 0.54), complication rates (p = 0.32) and hospital stay (p = 0.23). Operative time was longer for Madigan procedures (p = 0.05). The 1-year MSHQ and IIEF scores were significantly higher in the Madigan cohort (p = 0.008 and p = 0.04, respectively).

CONCLUSION

RASP proved to be a safe surgical approach, providing an effective and durable relief of obstructive symptoms at mid-term follow-up regardless of the technique used. The Madigan technique provided significant benefits in terms of self-assessed quality of sexual function.

ICG-induced NIR fluorescence mapping in patients with head & neck tumors after the previous radiotherapy

BACKGROUND

The distinction between tumor and healthy tissues is complicated in the areas previously subjected to radiation therapy (RT). This is related to the fact that tissues can undergo delayed and irreversible deterioration such as inflammation, vascular alteration and fibrosis. The trials related to the fluorescence -guided surgery (FSG) in Head and Neck Squamous Cell Carcinoma (HNSCC) patients, previously subjected to RT, have not yet been reported. The present study addresses for the first time the possibilities of tumor near-infrared (NIR) imaging using Indocynaine Green (ICG) in irradiated areas.

METHODS

Four patients with histologically confirmed HNSCC were included in this study. All included patients were previously treated with RT with at least 50 Gy. RT-radiation fields from original treatment fully encompassed the second tumor or recurrence. ICG was injected via cephalic vein 45 min before the images were captured using a NIR camera system Artemis. The images were also captured before ICG injection serving as background signal. The fluorescence intensity measurements were carried out using specially designed software.

RESULTS

ICG fluorescence clearly demonstrated a significant difference in fluorescence intensity between healthy and tumor tissues in 2 of 4 patients. Histology post-resection analysis confirmed a complete tumor resection with safe surgical margins. No difference between tumor and surrounding healthy tissue was detected in patients with an epidermoid carcinoma developed from sclerohypertrophic lichen.

CONCLUSIONS

In our pilot study, we clearly established the feasibility of using NIR FGS with ICG to delineate tumor and healthy tissues in irradiated areas in infiltrating lichen-free tumors.

Optical Imaging of Triple-Negative Breast Cancer Cells in Xenograft Athymic Mice Using an ICAM-1-Targeting Small-Molecule Probe

PURPOSE

The development of early, accurate diagnostic strategies for triple-negative breast cancer (TNBC) remains a significant challenge. Intercellular adhesion molecule-1 (ICAM-1) overexpressed in human TNBC cells is a potential molecular target and biomarker for diagnosis. In this study, small-molecule probe (denoted as γ3-Cy5.5) constructed with a short 17-mer linear peptide (γ3) and near-infrared fluorescence (NIRF) dye cyanine 5.5 (Cy5.5) was used to detect the expression of ICAM-1 in vitro and in vivo, and to diagnose TNBC via NIRF imaging.

PROCEDURES

Western blotting and flow cytometric analysis were used for the detection of ICAM-1 expression in MDA-MB-231 and MCF-7 cells. The cytotoxicity of the small-molecule probe γ3-Cy5.5 was detected using the CCK8 assay. The in vitro targeting of the small-molecule probe γ3-Cy5.5 was verified via flow cytometry and a laser scanning confocal microscope. Finally, the targeting of small-molecule probe in vivo and ex vivo was observed by NIRF imaging.

RESULTS

Western blotting and flow cytometry demonstrate that ICAM-1 was highly expressed in the MDA-MB-231 TNBC cell line. Laser confocal microscopy and flow cytometry results show that TNBC cells have an increased cellular uptake of γ3-Cy5.5 compared to the control probe γ3S-Cy5.5. With in vivo NIRF, a significantly higher Cy5.5 signal appeared in the tumors of mice administered γ3-Cy5.5 than those treated with γ3S-Cy5.5. The target-to-background ratio observed on the NIRF images was significantly higher in the γ3-Cy5.5 group (10.2, 13.6) compared with the γ3S-Cy5.5 group (4.4, 4.0) at 1 and 2 h, respectively.

CONCLUSIONS

This is the first report of the use of ICAM-1-specific small-molecule probe for in vivo NIRF optical imaging of TNBC. This method provides a noninvasive and specific strategy for the early diagnosis of TNBC.

Real-time surveillance of surgical margins via ICG-based near-infrared fluorescence imaging in patients with OSCC

Background

Local recurrence is the main cause of death among patients with oral squamous cell carcinoma (OSCC). This study assessed near-infrared fluorescence (NIF) imaging and spectroscopy to monitor surgical margins intraoperatively for OSCC.

Methods

Cytological and animal experiments were first performed to confirm the feasibility of monitoring surgical margins with NIF imaging and spectroscopy. Then, 20 patients with OSCC were included in the clinical trials. At 6–8 h after 0.75 mg/kg indocyanine green (ICG) injection, all patients underwent surgery with NIF imaging. During the surgery, both NIF images and quantified fluorescence intensity were acquired to monitor the surgical margins.

Results

In cytological and animal experiments, the results showed it was feasible to monitor surgical margins with NIF imaging and spectroscopy. Fluorescence was detected in primary tumors in all patients. The fluorescence intensities of the tumor, peritumoral, and normal tissues were 398.863 ± 151.47, 278.52 ± 84.89, and 274.5 ± 100.93 arbitrary units (AUs), respectively (P < 0.05). The SBR of tumor to peritumoral tissue and normal tissues was computed to be 1.45 ± 0.36 and 1.56 ± 0.41, respectively. After primary tumor excision, the wounds showed abnormal fluorescence in four patients (4/20), and residual cancer cells were confirmed by pathological examination in two patients (2/20).

Conclusion

These findings confirmed the complementary value of NIF imaging during radical tumor resection of OSCC. Before tumor resection, we could utilize the fluorescence margin produced by ICG NIF imaging to determine the surgical margin. Moreover, after tumor blocks were removed, the status of surgical margin could also be evaluated rapidly by ICG NIF imaging of tumor bed and in vitro specimens.

Transferrin receptor 1 targeted optical imaging for identifying glioma margin in mouse models

OBJECTIVE

Optical molecular imaging technology that indiscriminately detects intracranial glioblastoma (GBM) can help neurosurgeons effectively remove tumor masses. Transferrin receptor 1 (TfR 1) is a diagnostic and therapeutic target in GBM. A TfR 1-targeted peptide, CRTIGPSVC (CRT), was shown to cross the blood brain barrier (BBB) and accumulate at high levels in GBM tissues. In this study, we synthesized a TfR 1-targeted near-infrared fluorescent (NIRF) probe, Cy5-CRT, for identifying the GBM tissue margin in mouse models.

METHODS

We initially confirmed the overexpression of TfR 1 in GBM and the tumor-specific homing ability of Cy5-CRT in subcutaneous and orthotopic GBM mouse models. We then examined the feasibility of Cy5-CRT for identifying the tumor margin in orthotopic GBM xenografts. Finally, we compared Cy5-CRT with the clinically used fluorescein sodium in identifying tumor margins.

RESULTS

Cy5-CRT specifically accumulated in GBM tissues and detected the tumor burden with exceptional contrast in mice with orthotopic GBM, enabling fluorescence-guided GBM resection under NIRF live imaging conditions. Importantly, Cy5-CRT recognized the GBM tissue margin more clearly than fluorescein sodium.

CONCLUSIONS

The TfR 1-targeted optical probe Cy5-CRT specifically differentiates tumor tissues from the surrounding normal brain with high sensitivity, indicating its potential application for the precise surgical removal of GBM.

Evaluation of a novel ovarian cancer-specific fluorescent antibody probe for targeted near-infrared fluorescence imaging

Background

To meet clinical needs, fluorescence-guided surgery has emerged as a new technique that guides surgeons in the resection of cancerous tissue by highlighting tumour lesions during surgery. We aimed to evaluate the novel ovarian cancer-specific antibody fluorescent probe COC183B2-800 (COC183B2 conjugated with IRDye800CW) in tumour-specific imaging to determine if it can help surgeons remove malignant lesions under fluorescence guidance.

Methods

The expression of OC183B2 antigen in epithelial ovarian cancer (EOC) tissues and cell lines was determined using immunohistochemistry (IHC). Western blotting was used to verify the expression of OC183B2 in SKOV3-Luc tumours. Antibodies against OC183B2 and mouse immunoglobulin G1 (IgG1) were conjugated with IRDye800CW to develop the antibody fluorescent probes COC183B2-800 and IgG-800 (immunoglobulin G1 conjugated with IRDye800CW). A subcutaneous mouse tumour model of SKOV3-Luc cells was constructed. Bioluminescent imaging (BLI) was conducted to detect the tumour location. Near-infrared fluorescence (NIRF) imaging was performed after the mice were injected with imaging agents. The mice were sacrificed 96 h postinjection, and the biodistribution assays were performed using NIRF imaging.

Results

In 69 EOC patients, the total positive rate of OC183B2 in EOC tissues was 89.9% (62/69). Expression of the OC183B2 antigen was positive in SKOV3-Luc, 3AO, ES2 and A2780 cells. The OC183B2 antigen could be detected in SKOV3-Luc tumours. NIRF imaging of the COC183B2-800 probe at different doses showed a high fluorescent signal at the tumour location that was in line with the site detected by bioluminescent imaging. The tumour background ratio (TBR) was significantly higher in the COC183B2-800 group than in the IgG-800, IRDye800CW and PBS groups. The fluorescent probe COC183B2-800 is metabolized mainly through the liver and does not accumulate in other organs.

Conclusions

COC183B2-800 shows effective tumour-specific targeting of EOC and is a promising diagnostic and therapeutic tool for fluorescence-guided surgery.

Surface-Registration Frameless Stereotactic Navigation Is Less Accurate During Prone Surgeries: Intraoperative Near-Infrared Visualization Using Second Window Indocyanine Green Offers an Adjunct

BACKGROUND

Frameless neuronavigation allows neurosurgeons to visualize and relate the position of surgical instruments to intracranial pathologies based on preoperative tomographic imaging. However, neuronavigation can often be inaccurate. Multiple factors have been proposed as potential causes, and new technologies are needed to overcome these challenges.

OBJECTIVE

To evaluate the accuracy of neuronavigation systems compared to near-infrared (NIR) fluorescence imaging using Second Window Indocyanine Green, a novel technique, and to determine factors that lead to neuronavigation errors.

METHODS

A retrospective analysis was conducted on 56 patients who underwent primary resections of intracranial tumors. Patients received 5 mg/kg ICG approximately 24 h preoperatively. Intraoperatively, neuronavigation was used to plan craniotomies to place the tumors in the center. After craniotomy, NIR imaging visualized tumor-specific NIR signals. The accuracy of neuronavigation and NIR fluorescence imaging for delineating the tumor boundary prior to durotomy was compared.

RESULTS

The neuronavigation centers and NIR centers were 23.0 ± 7.7 % and 2.6 ± 1.1 % deviated from the tumor centers, respectively, relative to the craniotomy sizes. In 12 cases, significant changes were made to the planned durotomy based on NIR imaging. Patient position was a significant predictor of neuronavigation inaccuracy on both univariate and multivariate analysis, with the prone position having significantly higher inaccuracy (29.2 ± 8.1 %) compared to the supine (16.2 ± 8.1 %, p value < 0.001) or the lateral (17.9 ± 5.1 %, p value = 0.003) positions.

CONCLUSION

Patient position significantly affects neuronavigation accuracy. Intraoperative NIR fluorescence imaging before durotomy offers an opportunity to readjust the neuronavigation image space to better align with the patient space.

A lysosome specific, acidic-pH activated, near-infrared Bodipy fluorescent probe for noninvasive, long-term, in vivo tumor imaging

Long-term, in vivo, fluorescent cell tracking probes are useful for understanding complex cellular processes including tissue regeneration, communication, development, invasion, and cancer metastasis. A near-infrared fluorescent, water-soluble probe is particularly important for studying these biological events and processes. Herein, a lysosome specific, near-infrared Bodipy probe with increased fluorescent intensity in the acidic, lysosome environment is reported. This Bodipy probe is packaged in a nanoparticle using DSPE-PEG₂₀₀₀. The resulting nanoparticle is intravenously delivered to a tumor xenograft, where the fluorescent Bodipy becomes useful for non-invasive, long-term, in vivo fluorescent tumor imaging for periods greater than 36 days. These long-term, in vitro and in vitro tracking data indicate that the described Bodipy nanoparticles hold great potential for monitoring biological processes.