Clinical and pathological predictors of engraftment for patient-derived xenografts in lung adenocarcinoma.

Patient-derived xenografts (PDXs) are increasingly utilized in preclinical drug efficacy studies due to their ability to retain the molecular, histological, and drug response characteristics of patient tumors. This study aimed to investigate the factors influencing the successful engraftment of PDXs. Lung adenocarcinoma PDXs were established using freshly resected tumor tissues obtained through surgery. Radiological data of pulmonary nodules from this PDX cohort were analyzed, categorizing them into solid tumors and tumors with ground-glass opacity (GGO) based on preoperative CT images. Gene mutation status was obtained from next generation sequencing data and MassARRAY panel. A total of 254 resected primary lung adenocarcinomas were utilized for PDX establishment, with successful initial engraftment in 58 cases (22.8 %); stable engraftment defined as at least three serial passages was observed in 43 cases (16.9 %). The stable engraftment rates of PDXs from solid tumors and tumors with GGO were 22.1 % (42 of 190 cases) and 1.6 % (1 of 64 cases), respectively (P < 0.001). Adenocarcinomas with advanced stage, poor differentiation, solid histologic subtype, and KRAS or TP53 gene mutations were associated with stable PDX engraftment. Avoiding tumors with GGO features could enhance the cost-effectiveness of establishing PDX models from early-stage resected lung adenocarcinomas.

Investigating the effects of a temperature dependent photodynamic dose: A numerical study.

SIGNIFICANCE: Photodynamic therapy (PDT) and photothermal therapy (PTT) show promise as cancer treatments, but challenges in generating large ablative volumes for deep-seated tumours persist. Using simulations, this study investigates combined PDT and PTT to increase treatment volumes, including the impact of a temperature-dependent PDT dose on the treatment volume radius. APPROACH: A finite-element model, using the open-source SfePy package, was developed to simulate combined interstitial photothermal and photodynamic treatments. Results compared an additive dose model to a temperature-dependent dose model with enhanced PDT dosimetry and examined typical clinical scenarios for possible synergistic effects. RESULTS: Findings revealed that the temperature-dependent dose model could significantly expand the damage radius compared to the additive model, depending on the tissue and drug properties. CONCLUSIONS: Characterizing synergistic effects of PDT and PTT could enhance treatment planning. Future work is ongoing to implement additional variables, such as photosensitizer photobleaching, and spatial and temporally varying oxygenation.

Assessment of effectiveness and safety of thrombolytic therapy to pulmonary emboli by endobronchial ultrasound-guided transbronchial needle injection.

Objective: Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) may effectively treat acute pulmonary embolisms (PEs). Here, we assessed the effectiveness of clot dissolution and safety of tissue plasminogen activator (t-PA) injection using EBUS-TBNI in a 1-week survival study of a porcine PE model. Methods: Six pigs with bilateral PEs were used: 3 for t-PA injection using EBUS-TBNI (TBNI group) and 3 for systemic administration of t-PA (systemic group). Once bilateral PEs were created, each 25 mg of t-PA injection using EBUS-TBNI for bilateral PEs (a total of 50 mg t-PA) and 100 mg of t-PA systemic administration was performed on day 1. Hemodynamic parameters, blood tests, and contrast-enhanced computed tomography scans were carried out at several time points. On day 7, pigs were humanely killed to evaluate the residual clot volume in the pulmonary arteries. Results: The average of percent change of residual clot volumes was significantly lower in the TBNI group than in the systemic group (%: systemic group 36.6 ± 22.6 vs TBNI group 9.6 ± 6.1, P < .01) on day 3. Considering the elapsed time, the average decrease of clot volume per hour at pre-t-PA to post t-PA was significantly greater in the TBNI group than in the systemic group (mm3/hour: systemic 68.1 ± 68.1 vs TBNI 256.8 ± 148.1, P < .05). No hemorrhage was observed intracranially, intrathoracically, or intraperitoneally on any contrast-enhanced computed tomography images. Conclusions: This study revealed that t-PA injection using EBUS-TBNI is an effective and safe way to dissolve clots.

Laser interstitial thermal therapy of lung lesions near large vessels: a numerical study.

Objective.Laser interstitial thermal therapy (LITT) is an evolving hyperthermia-based technology that may offer a minimally invasive alternative to inoperable lung cancer. LITT of perivascular targets is challenged by higher risk of disease recurrence due to vascular heat sinks, as well as risk of damage to these vascular structures. The objective of this work is to examine the impact of multiple vessel parameters on the efficacy of the treatment and the integrity of the vessel wall in perivascular LITT.Approach.A finite element model is used to examine the role of vessel proximity, flow rate, and wall thickness on the outcome of the treatment. Main result. The simulated work indicates that vessel proximity is the major factor in driving the magnitude of the heat sink effect. Vessels situated near the target volume may act as a protective measure for reducing healthy tissue damage. Vessels with thicker walls are more at risk of damage during treatment. Interventions to reduce the flow rate may reduce the vessel's heat sink effect but may also result in increased risk of vascular wall damage. Lastly, even at reduced blood flow rates, the volume of blood reaching the threshold of irreversible damage (>43 °C) is negligible compared to the volume of blood flow throughout the treatment duration.Significance.This investigative simulation yields results that may help guide clinicians on treatment planning near large vessels.

Transbronchial real-time lung tumor localization with folate receptor-targeted near-infrared molecular imaging: A proof of concept study in animal models.

OBJECTIVE: The diagnostic yield of bronchoscopy is not satisfactory, even with recent navigation technologies, especially for tumors located outside of the bronchial lumen. Our objective was to perform a preclinical assessment of folate receptor-targeted near-infrared imaging-guided bronchoscopy to detect peribronchial tumors. METHODS: Pafolacianine, a folate receptor-targeted molecular imaging agent, was used as a near-infrared fluorescent imaging agent. An ultra-thin composite optical fiberscope was used for laser irradiation and fluorescence imaging. Subcutaneous xenografts of KB cells in mice were used as folate receptor-positive tumors. Tumor-to-background ratio was calculated by the fluorescence intensity value of muscle tissues acquired by the ultra-thin composite optical fiberscope system and validated using a separate spectral imaging system. Ex vivo swine lungs into which pafolacianine-laden KB tumors were transplanted at various sites were used as a peribronchial tumor model. RESULTS: With the in vivo murine model, tumor-to-background ratio observed by ultra-thin composite optical fiberscope peaked at 24 hours after pafolacianine injection (tumor-to-background ratio: 2.56 at 0.05 mg/kg, 2.03 at 0.025 mg/kg). The fluorescence intensity ratios between KB tumors and normal mouse lung parenchyma postmortem were 6.09 at 0.05 mg/kg and 5.08 at 0.025 mg/kg. In the peribronchial tumor model, the ultra-thin composite optical fiberscope system could successfully detect fluorescence from pafolacianine-laden folate receptor-positive tumors with 0.05 mg/kg at the carina and those with 0.025 mg/kg and 0.05 mg/kg in the peripheral airway. CONCLUSIONS: Transbronchial detection of pafolacianine-laden folate receptor-positive tumors by near-infrared imaging was feasible in ex vivo swine lungs. Further in vivo preclinical assessment is needed to confirm the feasibility of this technology.

Anatomic evaluation of Pancoast tumors using three-dimensional models for surgical strategy development.

OBJECTIVE: Pancoast tumor resection planning requires precise interpretation of 2-dimensional images. We hypothesized that patient-specific 3-dimensional reconstructions, providing intuitive views of anatomy, would enable superior anatomic assessment. METHODS: Cross-sectional images from 9 patients with representative Pancoast tumors, selected from an institutional database, were randomly assigned to presentation as 2-dimensional images, 3-dimensional virtual reconstruction, or 3-dimensional physical reconstruction. Thoracic surgeons (n = 15) completed questionnaires on the tumor extent and a zone-based algorithmic surgical approach for each patient. Responses were compared with surgical pathology, documented surgical approach, and the optimal "zone-specific" approach. A 5-point Likert scale assessed participants' opinions regarding data presentation and potential benefits of patient-specific 3-dimensional models. RESULTS: Identification of tumor invasion of segmented neurovascular structures was more accurate with 3-dimensional physical reconstruction (2-dimensional 65.56%, 3-dimensional virtual reconstruction 58.52%, 3-dimensional physical reconstruction 87.50%, P < .001); there was no difference for unsegmented structures. Classification of assessed zonal invasion was better with 3-dimensional physical reconstruction (2-dimensional 67.41%, 3-dimensional virtual reconstruction 77.04%, 3-dimensional physical reconstruction 86.67%; P = .001). However, selected surgical approaches were often discordant from documented (2-dimensional 23.81%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .084) and "zone-specific" approaches (2-dimensional 33.33%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .501). All surgeons agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction benefit surgical planning. Most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction would facilitate patient and interdisciplinary communication. Finally, most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction's benefits outweighed potential delays in care for model construction. CONCLUSIONS: Although a consistent effect on surgical strategy was not identified, patient-specific 3-dimensional Pancoast tumor models provided accurate and user-friendly overviews of critical thoracic structures with perceived benefits for surgeons' clinical practices.

Repeated photodynamic therapy mediates the abscopal effect through multiple innate and adaptive immune responses with and without immune checkpoint therapy.

In combination with immune checkpoint inhibitors, photodynamic therapy can induce robust immune responses capable of preventing local tumor recurrence and delaying the growth of distant, untreated disease (ie. the abscopal effect). Previously, we found that repeated photodynamic therapy (R-PDT) using porphyrin lipoprotein (PLP) as a photosensitizer, without the addition of an immune checkpoint inhibitor, can induce the abscopal effect. To understand why PLP mediated R-PDT alone can induce the abscopal effect, and how the addition of an immune checkpoint inhibitor can further strengthen the abscopal effect, we investigated the broader immune mechanisms facilitated by R-PDT and combination R-PDT + anti-PD-1 monoclonal antibody (αPD-1) in a highly aggressive, subcutaneous AE17-OVA mesothelioma dual tumor-bearing C57BL/6 mice. We found a 46.64-fold and 61.33-fold increase in interleukin-6 (IL-6) after R-PDT and combination R-PDT + αPD-1 relative to PBS respectively, suggesting broad innate immune activation. There was a greater propensity for antigen presentation in the spleen and distal, non-irradiated tumor draining lymph nodes, as dendritic cells and macrophages had increased expression of MHC class II, CD80, and CD86, after R-PDT and combination R-PDT + αPD-1. Concurrently, there was a shift in the proportions of CD4+ T cell subsets in the spleen, and an increase in the frequency of CD8+ T cells in the distal, non-irradiated tumor draining lymph nodes. While R-PDT had an acceptable safety profile, combination R-PDT + αPD-1 induced 1.26-fold higher serum potassium and 1.33-fold phosphorus, suggestive of mild laboratory tumor lysis syndrome. Histology revealed an absence of gross inflammation in critical organs after R-PDT and combination R-PDT + αPD-1 relative to PBS-treated mice. Taken together, our findings shed light on how the abscopal effect can be induced by PDT and strengthened by combination R-PDT + αPD-1, and suggests minimal toxicities after R-PDT.

Optimization of thrombolytic dose for treatment of pulmonary emboli using endobronchial ultrasound-guided transbronchial needle injection.

OBJECTIVE: Severe pulmonary embolism is often managed with thrombolysis. We sought to determine whether endobronchial ultrasound (EBUS)-guided transbronchial thrombolysis remained effective at lower alteplase doses, with the goal of minimizing potential bleeding risk. METHODS: Yorkshire pigs were anesthetized and ventilated. Preformed autologous blood clots were administered into bilateral pulmonary arteries via EBUS-guided transbronchial injection. After documenting baseline clot sizes, alteplase was injected into the clots using a 25-gauge transbronchial needle and clot dissolution was monitored over 30 minutes. The study was performed in 2 phases. First, alteplase doses of 5 and 12.5 mg were evaluated. These results informed dose selection for the second phase. Results were compared with 25-mg dose data using EBUS from a previous study. RESULTS: In the first phase, 3 clots were evaluated. Distilled water, 5 mg, and 12.5 mg alteplase were administered. The dissolved clot volume (Vdis) and percentage clot volume loss (Rdis) were -10.9, 111.6, and 160.3 mm3, and -1.6%, 11.0%, and 59.3%, respectively. In the second phase, alteplase doses of 5, 10, and 15 mg were evaluated in 12 clots across 6 pigs. The Vdis were 247.5 mm3 (Rdis, 20.1%), 910.8 mm3 (Rdis, 80.9%), and 798.3 mm3 (Rdis, 76.0%) for 5, 10, and 15 mg alteplase, respectively. Remakably reduced performance was observed with 5 mg alteplase versus 10 mg (Vdis: P < .001, Rdis: P < .001), and 15 mg (Vdis: P = .004; Rdis: P < .001). No complications were observed. CONCLUSIONS: Alteplase doses ≥10 mg were optimal for EBUS-guided transbronchial thrombolysis. This technique might represent an effective alternative therapy for central pulmonary embolism.

Preclinical feasibility of bronchoscopic fluorescence-guided lung sentinel lymph node mapping.

OBJECTIVE: Lung sentinel lymph node mapping, where peritumorally injected material is tracked through the lymphatics, aims to find the first potential sites of nodal metastasis. We sought to evaluate the preclinical feasibility of bronchoscopic fluorescence-guided sentinel lymph node mapping. METHODS: Healthy Yorkshire pigs were used; sentinel lymph node mapping was performed with indocyanine green. The primary fluorescence imaging method was an ultrathin composite fiberscope placed in the bronchoscope working channel. Secondary methods used a fluorescence thoracoscope placed in the trachea (rigid bronchoscopy) and pretracheal fascial plane (mediastinoscopy) to validate ultrathin composite fiberscope settings for sentinel lymph node detection. A tracheostomy was created, and the pig was placed in a lateral decubitus position. Transbronchial intraparenchymal indocyanine green injection was performed primarily in the right lower lobe. Ultrathin composite fiberscope and rigid bronchoscopy were performed with (n = 6) or without (n = 2) mediastinoscopy, with the former group guiding dose and ultrathin composite fiberscope optimization. Fluorescent targets were interrogated by endobronchial ultrasound before ultrathin composite fiberscope-guided transbronchial needle aspiration. Specimen fluorescence was documented before creating cytological smears. Pigs were killed postprocedure for nodal dissection. RESULTS: A total of 100 µL of 10 mg/mL indocyanine green generated strong transbronchial fluorescence with low risk of indocyanine green contamination. Fluorescence was detectable by 10 minutes postinjection. There was concordance among ultrathin composite fiberscope, rigid bronchoscopy, and mediastinoscopy. Except for 1 pig with airway contamination, ultrathin composite fiberscope-guided endobronchial ultrasound transbronchial needle aspiration obtained fluorescent material in all pigs. Specimen fluorescence was associated with specimen adequacy. CONCLUSIONS: Bronchoscopic fluorescence-guided sentinel lymph node mapping was feasible, with specimen fluorescence providing real-time feedback on sentinel lymph node biopsy success. If translated to clinical practice, attention must be paid to minimizing indocyanine green leakage.

Preclinical evaluation of thin convex probe endobronchial ultrasound-guided transbronchial needle aspiration for intrapulmonary lesions.

Background: Conventional flexible bronchoscopy has not achieved the high diagnostic yield for intrapulmonary lesions as seen with image-guided transthoracic biopsy. A thin convex probe endobronchial ultrasound bronchoscope (TCP-EBUS) with a 5.9-mm tip was designed to improve peripheral access over conventional EBUS bronchoscopes to facilitate real-time sampling of intrapulmonary lesions under ultrasound guidance. Methods: TCP-EBUS was inserted into the distal airways of ex-vivo human lungs to assess bronchial accessibility relative to clinically available bronchoscopes. The short- (≤1 h) and medium-term (≤10 d) safety of TCP-EBUS insertion and EBUS-guided transbronchial needle aspiration (TBNA) using a 25-gauge needle were evaluated physiologically and radiologically in live pigs. TCP-EBUS-guided TBNA feasibility was assessed in-vivo with pig intrapulmonary pseudo-tumors and ex-vivo with resected human lung cancer specimens. Results: For bronchial accessibility, TCP-EBUS demonstrated greater reach than the 6.6-mm convex probe endobronchial ultrasound (CP-EBUS) in all bronchi, as well as surpassed a 5.5-mm conventional bronchoscope in 63% (131/209) and a 4.8-mm conventional bronchoscope in 27% (57/209) of assessed bronchi. The median bronchial generation and the mean diameter of bronchi TCP-EBUS reached was 4 (range, 3-7) and 3.3±0.7 mm, respectively. No major complications related to TCP-EBUS-guided TBNA in distal airways were observed in the live pigs. Scattered mucosal erythema of the bronchial walls was observed immediately after TCP-EBUS insertion; this self-resolved by day 10. TCP-EBUS could successfully reach and visualize intrapulmonary targets via ultrasound, with no difficulty in needle deployment or sampling. Conclusions: TCP-EBUS has the potential to facilitate safe real-time transbronchial sampling of intrapulmonary lesions in the central and middle lung fields.

Development of a minimally invasive pulmonary porcine embolism model via endobronchial ultrasound.

Background: Current massive pulmonary embolism (PE) animal models use central venous access to deliver blood clots, which have features of random clot distribution and potentially fatal hemodynamic compromise. A clinically relevant preclinical model for generating pulmonary emboli in a more controlled fashion would be of value for a variety of research studies, including initial evaluation of novel therapeutic approaches. Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) is a newly established approach for peri-tracheal/bronchial targets. The purpose of the present work was to establish a minimally invasive PE model in swine via a transbronchial approach. Methods: In anesthetized Yorkshire pigs, a 21-G EBUS-guided transbronchial needle aspiration (EBUS-TBNA) needle was introduced into the pulmonary artery under EBUS guidance. Autologous blood clots were administered into the right and left lower pulmonary arteries sequentially (PE1 and PE2, respectively). Hemodynamic and biochemical responses were evaluated. Results: Ten pigs were evaluated; all 20 blood clots (6.3±1.9 mL) were successfully injected. After injection, mean pulmonary artery pressure (mPAP; mmHg) increased (baseline: 16.6±5.6 vs. PE1: 24.5±7.6, P<0.0001 vs. PE2: 26.9±6.7, P<0.0001), and a positive correlation was observed between clot volume and change in mPAP (PE1: r=0.69, P=0.025; PE1 + PE2: r=0.60, P=0.063). Mean arterial pressure (MAP; mmHg) (baseline: 57.5±5.1 vs. PE1: 59.0±9.1, P=0.918 vs. PE2: 60.9±9.6, P=0.664) remained stable. No complications were observed. Conclusions: EBUS allows minimally invasive, precise, and reliable generation of pulmonary emboli in pigs. This model may serve as an important tool for new PE-related diagnostic and therapeutic research.

Pilot study using virtual 4-D tracking electromagnetic navigation bronchoscopy in the diagnosis of pulmonary nodules: a single center prospective study.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) is a navigation technology intended to improve the diagnostic yield of pulmonary nodules. However, nodule displacement due to respiratory motion may compromise the accuracy of the navigation guidance. The Veran SPiNDrive ENB system employs respiratory-gating (4D-tracking) to compensate for this motion. The aim of the present study was to evaluate the diagnostic performance and safety of the Veran SPiNDrive system for biopsy of pulmonary nodules. METHODS: Adult patients with pulmonary nodules of ≥1 cm were enrolled at a single center. Both conventional bronchoscopy and 4D-tracking ENB were performed in one procedure session under general anesthesia, with the procedure order being randomly assigned. Radial probe endobronchial ultrasound and fluoroscopy were used in both groups. The diagnostic performance, safety, total procedure time, and total fluoroscopy time of the ENB phase were compared to the corresponding conventional bronchoscopy phase. RESULTS: The study was terminated due to poor accrual; a total of eleven patients were enrolled. The mean size of pulmonary nodules was 2.1 cm. The sensitivity for malignancy was 67% (6/9) and 56% (5/9) with conventional bronchoscopy and with 4D-tracking ENB, respectively. Two cases developed minor bleeding after conventional bronchoscopy, while no complications were observed after 4D-tracking ENB. The mean procedure time was 16.1 and 21.7 min (P=0.090), and the mean duration time for fluoroscopy use was 77 and 44 sec (P=0.056) for the conventional bronchoscopy and the 4D-tracking ENB phases, respectively. CONCLUSIONS: The diagnostic performance of the Veran SPiNDrive 4D-tracking ENB did not exceed that of conventional bronchoscopy for pulmonary nodules. No complications were seen during 4D-tracking ENB. A study with a larger number of participants is required for further assessment.

Thrombolysis of Pulmonary Emboli via Endobronchial Ultrasound-Guided Transbronchial Needle Injection.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) is a novel technique for treating peribronchial targets. The aim of this study was to evaluate preliminary feasibility of thrombolysis of pulmonary emboli via EBUS-TBNI. METHODS: Yorkshire pigs (30-48 kg) were anesthetized and mechanically ventilated. Pre-formed autologous clots were injected sequentially into bilateral lower pulmonary arteries in bilateral models (PE1 and PE2, respectively) or into 1 side in unilateral models using a 21-gauge EBUS-TBNA needle under EBUS guidance. In the bilateral model, 2 hours after clot injection either 25 mL of tissue-plasminogen activator (t-PA; 1mg/mL) or distilled water were administered into each embolus via 25-gauge EBUS-TBNA needle. In the unilateral model, 25 mg t-PA was administered intravenously. Hemodynamic parameters were monitored continuously, and clot dissolved volume was evaluated by EBUS 30 minutes post-treatment administration. RESULTS: All clots (6.1 ± 1.7 mL) were successfully injected as documented by EBUS Doppler imaging. Clot injection in the bilateral model (n = 6) increased pulmonary arterial pressure (mm Hg: Baseline 19.2 ± 5.9 vs PE1: 26.7 ± 9.1, P = .005 vs PE2 29.9 ± 7.1, P = .0007). After t-PA TBNI in the bilateral model (n = 6), pulmonary arterial pressure at 30 minutes post-injection showed improvement (mm Hg: PE2 29.9 ± 7.1 vs post-t-PA 24.4 ± 3.9, P = .0283). Treatment with t-PA TBNI demonstrated superior clot dissolution at 30 minutes post-treatment (dissolved mm3: t-PA TBNI 625.4 ± 156.6 vs t-PA intravenously: 181.6 ± 94.3, P = .0003 vs distilled water TBNI 42.5 ± 33.0, P < .0001). There were no complications. CONCLUSIONS: EBUS-guided transbronchial thrombolysis may be a feasible approach for treating central pulmonary emboli.

A preclinical research platform to evaluate photosensitizers for transbronchial localization and phototherapy of lung cancer using an orthotopic mouse model.

BACKGROUND: Establishing the efficacy of novel photosensitizers (PSs) for phototherapy of lung cancer requires in vivo study prior to clinical evaluation. However, previously described animal models are not ideal for assessing transbronchial approaches with such PSs. METHODS: An ultra-small parallel-type composite optical fiberscope (COF) with a 0.97 mm outer diameter tip. The integration of illumination and laser irradiation fibers inside the COF allows simultaneous white-light and fluorescence imaging, as well as real-time monitoring of tip position during laser phototherapy. An orthotopic lung cancer mouse model was created with three human lung cancer cell lines transbronchially inoculated into athymic nude mice. The COF was inserted transbronchially into a total of 15 mice for tumor observation. For in vivo fluorescence imaging, an organic nanoparticle, porphysome, was used as a PS. Laser excitation through the COF was performed at 50 mW using a 671 nm source. RESULTS: The overall success rate for creating orthotopic lung tumors was 71%. Transbronchial white light images were successfully captured by COF. Access to the left main bronchus was successful in 87% of mice (13/15), the right main bronchus to the cranial lobe bronchus level in 100% (15/15), and to the right basal trifurcation of the middle lobe, caudal lobe and accessory lobe in 93% (14/15). For transbronchial tumor localization of orthotopic lung cancer tumors, PS-laden tumor with the strong signal was clearly contrasted from the normal bronchial wall. CONCLUSIONS: The ultra-small COF enabled reliable transbronchial access to orthotopic human lung cancer xenografts in vivo. This method could serve as a versatile preclinical research platform for PS evaluation in lung cancer, enabling transbronchial approaches in in vivo survival models inoculated with human lung cancer cells.

Repeated porphyrin lipoprotein-based photodynamic therapy controls distant disease in mouse mesothelioma via the abscopal effect.

While photodynamic therapy (PDT) can induce acute inflammation in the irradiated tumor site, a sustained systemic, adaptive immune response is desirable, as it may control the growth of nonirradiated distant disease. Previously, we developed porphyrin lipoprotein (PLP), a ∼20 nm nanoparticle photosensitizer, and observed that it not only efficiently eradicated irradiated primary VX2 buccal carcinomas in rabbits, but also induced regression of nonirradiated metastases in a draining lymph node. We hypothesized that PLP-mediated PDT can induce an abscopal effect and we sought to investigate the immune mechanism underlying such a response in a highly aggressive, dual subcutaneous AE17-OVA+ mesothelioma model in C57BL/6 mice. Four cycles of PLP-mediated PDT was sufficient to delay the growth of a distal, nonirradiated tumor four-fold relative to controls. Serum cytokine analysis revealed high interleukin-6 levels, showing a 30-fold increase relative to phosphate-buffered solution (PBS) treated mice. Flow cytometry revealed an increase in CD4+ T cells and effector memory CD8+ T cells in non-irradiated tumors. Notably, PDT in combination with PD-1 antibody therapy prolonged survival compared to monotherapy and PBS. PLP-mediated PDT shows promise in generating a systemic immune response that can complement other treatments, improving prognoses for patients with metastatic cancers.

Photoacoustic imaging to localize indeterminate pulmonary nodules: A preclinical study.

PURPOSE: Diagnosis and resection of indeterminate pulmonary nodules (IPNs) is a growing challenge with increased utilization of chest computed tomography. Photoacoustic (PA) -guided surgical resection with local injection of indocyanine green (ICG) may have utility for IPNs that are suspicious for lung cancer. This preclinical study explores the potential of PA imaging (PAI) to detect ICG-labeled tumors. MATERIALS AND METHODS: ICG uptake by H460 lung cancer cells was evaluated in vitro. A phantom study was performed to analyze PA signal intensity according to ICG concentration and tissue thickness/depth using chicken breast. PA signals were measured up to 48 hours after injection of ICG (mixed with 5% agar) into healthy subcutaneous tissue, subcutaneous H460 tumors and right healthy lung in nude mice. RESULTS: Intracellular ICG fluorescence was detected in H460 cells co-incubated with ICG in vitro. The concentration dependence of the PA signal was logarithmic, and PA signal decline was exponential with increasing tissue depth. The PA signal of 2 mg/mL ICG was still detectable at a depth of 22 mm in chicken breast. The PA signal from ICG mixed with agar was detectable 48 hours post injection into subcutaneous tissue and subcutaneous H460 tumors in nude mice. Similar features of PA signals from ICG-agar in mice lung were obtained. CONCLUSION: The results from this preclinical study suggests that PAI of injected ICG-agar may be beneficial for identifying deeply located tumors. These features may be valuable for IPNs.

Endobronchial Ultrasound-Guided Radiofrequency Ablation of Lung Tumors and Mediastinal Lymph Nodes: A Preclinical Study in Animal Lung Tumor and Mediastinal Adenopathy Models.

Radiofrequency ablation (RFA) can be a therapeutic option in medically inoperable lung cancer patients. In this study, we evaluated a prototype bipolar RFA device applicator that can be deployed from a standard endobronchial ultrasound (EBUS) bronchoscope to determine feasibility and histopathological analysis in animal models. Rabbit lung cancers were created by transbronchial injection of VX2 rabbit cancer cells. Once the tumors were developed, they were ablated transpleurally, under EBUS guidance using the prototype RFA device. The animals were then sacrificed for specimen resection. Pig inflammatory lung pseudo-tumors and lymphadenopathy were created by transbronchial injection of a talc paste and ablated transbronchially under EBUS guidance. Pigs were evaluated at 5 days, 2 weeks, and 4 weeks following ablation by bronchoscopy and cone beam computed tomography before necropsy. Nicotinamide adenine dinucleotide hydrogen diaphorase staining was employed to measure the ablation area. Twenty-four VX2 rabbit tumors were ablated. The total ablated area ranged from 0.6 to 3.0 cm2 (mean: 1.8 cm2), corresponding to a total energy range of 1 to 6 kJ. Six pig lung pseudo-tumors and 5 mediastinal lymph nodes were ablated. Adjacent airway ulceration was observed in 3 ablations of lymph nodes. These airway complications resolved within 4 weeks of RFA without any treatment. There was no hemoptysis, air embolism, respiratory distress, or other serious complication noted. In these 2 animal models, we provide evidence that EBUS-guided bipolar RFA is feasible and histopathology shows that can ablate lung tumors and mediastinal lymph nodes under real-time ultrasound guidance.

In situ tissue pathology from spatially encoded mass spectrometry classifiers visualized in real time through augmented reality.

Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. Spatially encoded pathology classifications are displayed at the site of laser sampling as color-coded pixels in an augmented reality video feed of the surgical field of view. This is enabled by two-way communication between surgical navigation and mass spectrometry data analysis platforms through a custom-built interface. Performance of the system was evaluated using murine models of human cancers sampled in situ in the presence of body fluids with a technical pixel error of 1.0 ± 0.2 mm, suggesting a 84% or 92% (excluding one outlier) cancer type classification rate across different molecular models that distinguish cell-lines of each class of breast, brain, head and neck murine models. Further, through end-point immunohistochemical staining for DNA damage, cell death and neuronal viability, spatially encoded PIRL-MS sampling is shown to produce classifiable mass spectral data from living murine brain tissue, with levels of neuronal damage that are comparable to those induced by a surgical scalpel. This highlights the potential of spatially encoded PIRL-MS analysis for in vivo use during neurosurgical applications of cancer type determination or point-sampling in vivo tissue during tumor bed examination to assess cancer removal. The interface developed herein for the analysis and the display of spatially encoded PIRL-MS data can be adapted to other hand-held mass spectrometry analysis probes currently available.