Modified in vivo lung perfusion allows for prolonged perfusion without acute lung injury

Mapping the metabolic responses to oxaliplatin-based chemotherapy with in vivo spatiotemporal metabolomics

Adjuvant chemotherapy improves the survival outlook for patients undergoing operations for lung metastases caused by colorectal cancer (CRC). However, a multidisciplinary approach that evaluates several factors related to patient and tumor characteristics is necessary for managing chemotherapy treatment in metastatic CRC patients with lung disease, as such factors dictate the timing and drug regimen, which may affect treatment response and prognosis. In this study, we explore the potential of spatial metabolomics for evaluating metabolic phenotypes and therapy outcomes during the local delivery of the anticancer drug, oxaliplatin, to the lung. 12 male Yorkshire pigs underwent a 3 h left lung in vivo lung perfusion (IVLP) with various doses of oxaliplatin (7.5, 10, 20, 40, and 80 mg/L), which were administered to the perfusion circuit reservoir as a bolus. Biocompatible solid-phase microextraction (SPME) microprobes were combined with global metabolite profiling to obtain spatiotemporal information about the activity of the drug, determine toxic doses that exceed therapeutic efficacy, and conduct a mechanistic exploration of associated lung injury. Mild and subclinical lung injury was observed at 40 mg/L of oxaliplatin, and significant compromise of the hemodynamic lung function was found at 80 mg/L. This result was associated with massive alterations in metabolic patterns of lung tissue and perfusate, resulting in a total of 139 discriminant compounds. Uncontrolled inflammatory response, abnormalities in energy metabolism, and mitochondrial dysfunction next to accelerated kynurenine and aldosterone production were recognized as distinct features of dysregulated metabolipidome. Spatial pharmacometabolomics may be a promising tool for identifying pathological responses to chemotherapy.

In vivo lung perfusion for prompt recovery from primary graft dysfunction after lung transplantation

BACKGROUND

No proven treatment after the development of primary graft dysfunction (PGD) is currently available. Here, we established a novel strategy of in vivo lung perfusion (IVLP) for the treatment of PGD. IVLP involves the application of an in vivo isolated perfusion circuit to an implanted lung. This study aimed to explore the effectiveness of IVLP vs conventional post-lung transplant (LTx) extracorporeal membrane oxygenation (ECMO) treatment using an experimental swine LTx PGD model.

METHODS

After 1.5-hour warm ischemia of the donor lungs, a left LTx was performed. Following the confirmation of PGD development, pigs were divided into 3 groups (n = 5 each): control (no intervention), ECMO, and IVLP. After 2 hours of treatment, a 4-hour functional assessment was conducted, and samples were obtained.

RESULTS

Significantly better oxygenation was achieved in the IVLP group (p ≤ 0.001). Recovery was confirmed immediately and maintained during the following 4-hour observation. The IVLP group also demonstrated better lung compliance than the control group (p = 0.045). A histologic evaluation showed that the lung injury score and terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed significantly fewer injuries and a better result in the wet-to-dry weight ratio in the IVLP group.

CONCLUSIONS

A 2-hour IVLP is technically feasible and allows for prompt recovery from PGD after LTx. The posttransplant short-duration IVLP strategy can complement or overcome the limitations of the current practice for donor assessment and PGD management.

In vivo solid phase microextraction for therapeutic monitoring and pharmacometabolomic fingerprinting of lung during in vivo lung perfusion of FOLFOX

In vivo lung perfusion (IVLP) is a novel isolated lung technique developed to enable the local, in situ administration of high-dose chemotherapy to treat metastatic lung cancer. Combination therapy using folinic acid (FOL), 5-fluorouracil (F), and oxaliplatin (OX) (FOLFOX) is routinely employed to treat several types of solid tumours in various tissues. However, F is characterized by large interpatient variability with respect to plasma concentration, which necessitates close monitoring during treatments using of this compound. Since plasma drug concentrations often do not reflect tissue drug concentrations, it is essential to utilize sample-preparation methods specifically suited to monitoring drug levels in target organs. In this work, in vivo solid-phase microextraction (in vivo SPME) is proposed as an effective tool for quantitative therapeutic drug monitoring of FOLFOX in porcine lungs during pre-clinical IVLP and intravenous (IV) trials. The concomitant extraction of other endogenous and exogenous small molecules from the lung and their detection via liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) enabled an assessment of FOLFOX's impact on the metabolomic profile of the lung and revealed the metabolic pathways associated with the route of administration (IVLP vs. IV) and the therapy itself. This study also shows that the immediate instrumental analysis of metabolomic samples is ideal, as long-term storage at -80 °C results in changes in the metabolite content in the sample extracts.

Transvenous Pulmonary Chemoembolization and Optional Microwave Ablation for Colorectal Lung Metastases

(1) Purpose: To evaluate tumor response and survival of patients with colorectal pulmonary metastases treated by transvenous pulmonary chemoembolization (TPCE) alone with palliative intent or TPCE followed by microwave ablation (MWA) with potentially curative intent. (2) Material and methods: A total of 164 patients (64 women and 100 men; mean age: 61.8 ± 12.7 years) with unresectable colorectal lung metastases and not responding to systemic chemotherapy, who either received repetitive TPCE (Group A) or TPCE followed by MWA (Group B), were retrospectively enrolled. The revised response evaluation criteria in solid tumors were used to assess treatment response in Group A. The oncological response in Group B was divided into local tumor progression (LTP) and intrapulmonary distant recurrence (IDR) after MWA. (3) Results: The 1-, 2-, 3-, and 4-year survival rates were 70.4%, 41.4%, 22.3%, and 5%, respectively, for all patients. In Group A; the rates of stable disease; progressive disease; and partial response were at 55.4%, 41.9%, and 2.7%, respectively. The rates of LTP and IDR were 3.8%, and 63.5%, respectively, in Group B. Conclusion: TPCE is an effective treatment for colorectal lung metastases, which can be performed alone or combined with MWA.

The metabolic fate of oxaliplatin in the biological milieu investigated during in vivo lung perfusion using a unique miniaturized sampling approach based on solid-phase microextraction coupled with liquid chromatography-mass spectrometry

Adjuvant chemotherapy after pulmonary metastasectomy for colorectal cancer may reduce recurrence and improve survival rates; however, the benefits of this treatment are limited by the significant side effects that accompany it. The development of a novel in vivo lung perfusion (IVLP) platform would permit the localized delivery of high doses of chemotherapeutic drugs to target residual micrometastatic disease. Nonetheless, it is critical to continuously monitor the levels of such drugs during IVLP administration, as lung injury can occur if tissue concentrations are not maintained within the therapeutic window. This paper presents a simple chemical-biopsy approach based on sampling with a small nitinol wire coated with a sorbent of biocompatible morphology and evaluates its applicability for the near-real-time in vivo determination of oxaliplatin (OxPt) in a 72-h porcine IVLP survival model. To this end, the pigs underwent a 3-h left lung IVLP with 3 doses of the tested drug (5, 7.5, and 40 mg/L), which were administered to the perfusion circuit reservoir as a bolus after a full perfusion flow had been established. Along with OxPt levels, the biocompatible solid-phase microextraction (SPME) probes were employed to profile other low-molecular-weight compounds to provide spatial and temporal information about the toxicity of chemotherapy or lung injury. The resultant measurements revealed a rather heterogeneous distribution of OxPt (over the course of IVLP) in the two sampled sections of the lung. In most cases, the OxPt concentration in the lung tissue peaked during the second hour of IVLP, with this trend being more evident in the upper section. In turn, OxPt in supernatant samples represented ∼25% of the entire drug after the first hour of perfusion, which may be attributable to the binding of OxPt to albumin, its sequestration into erythrocytes, or its rapid nonenzymatic biotransformation. Additionally, the Bio-SPME probes also facilitated the extraction of various endogenous molecules for the purpose of screening biochemical pathways affected during IVLP (i.e., lipid and amino acid metabolism, steroidogenesis, or purine metabolism). Overall, the results of this study demonstrate that the minimally invasive SPME-based sampling approach presented in this work can serve as (pre)clinical and precise bedside medical tool.

Determination of Optical Properties and Photodynamic Threshold of Lung Tissue for Treatment Planning of In Vivo Lung Perfusion Assisted Photodynamic Therapy

BACKGROUND

Isolated lung metastases in sarcoma and colorectal cancer patients are inadequately treated with current standard therapies. In Vivo Lung Perfusion, a novel platform, could overcome limitations to photodynamic therapy treatment volumes by using low cellular perfusate, removing blood, theoretically allowing greater light penetration. To develop personalized photodynamic therapy protocols requires in silico light propagation simulations based on optical properties and maximal permissible photodynamic threshold dose of lung tissue. This study presents quantification of optical properties for two perfusates and the photodynamic threshold for 5-ALA and Chlorin e6.

METHODS

Porcine and human lungs were placed on Ex Vivo Lung Perfusion, and perfused with acellular solution or blood. Isotropic diffusers were placed within bronchi and on lung surface for light transmission measurements, from which absorption and light scattering properties were calculated at multiple wavelengths. Separately, pigs were injected with 5-ALA or Chlorin e6, and lung tissue was irradiated at increasing doses. Resultant lesion sizes were measured by CT and histology to quantify the photodynamic threshold.

RESULTS

Low cellular perfusate reduced the tissue absorption coefficient significantly, increasing penetration depth of light by 3.3 mm and treatment volumes 3-fold. The photodynamic threshold for lung exposed to 5-ALA was consistent with other malignancies. Chlorin e6 levels were undetectable in lung tissue and did not demonstrate photodynamic-induced necrosis.

CONCLUSIONS

Light penetration with low cellular perfusate is significantly greater and could enable treatments for diffuse disease. This data aids photodynamic treatment planning and will guide clinical translation of photodynamic therapy protocols in the lung, especially during lung perfusion.

Effects of blood oxygen saturation on pulmonary artery remodeling in an in vitro perfusion circuit model

Background

Patients with transposition of the great arteries are likely to survive surgery despite severe pulmonary artery hypertension. However, the underlying mechanisms remain largely unknown. The present study aimed to test the hypothesis that high blood oxygen saturation may protect the pulmonary artery from remodeling.

Methods

An in vitro pulmonary artery perfusion model was successfully performed by connecting rabbit pulmonary artery to a closed perfusion circuit. Twenty-five rabbits were divided randomly into 5 groups according to exposure conditions: Normal Control (NC) group (unperfused normal pulmonary artery), High Saturation (HS) group (oxygen saturation range: 90–100%), Medium Saturation (MS) group (oxygen saturation: 65–75%); Low Saturation (LS) group (oxygen saturation: 40–50%), and anti-hypoxia inducible factor-1α (anti-HIF-1α) group (oxygen saturation range: 40–50%, and LW6, which is a novel HIF-1α inhibitor; was added). By staining and optical microscopy examination, pathological morphology was analyzed, and the protein expression levels of HIF-1α, angiotensin-II (Ang-II), endothelin-1 (ET-1), Rho-associated protein kinase-1 (Rock-1), and matrix metallopeptidase-2 (MMP-2) were determined by Western blotting.

Results

The amounts of elastin, muscle, and collagen and the protein levels of ET-1, HIF-1α, Rock-1, and MMP-2, increased significantly with decreased oxygen saturation in the perfusion circuit. A significant improvement in pathological morphology was observed in the anti-HIF1α group. The expression of HIF-1α, ET-1, Ang-II, Rock-1, and MMP-2 in the anti-HIF1α group was also significantly lower than that in the LS group.

Conclusions

In the closed perfusion model, high blood oxygen saturation alleviated pulmonary vascular structural remodeling. Similar beneficial effects were observed when inhibiting the HIF-1α protein, suggesting a key role for HIF-1α in pulmonary artery remodeling.

Two Hours of In Vivo Lung Perfusion Improves Lung Function in Sepsis-Induced Acute Respiratory Distress Syndrome

Sepsis is the leading cause of acute respiratory distress syndrome (ARDS) in adults and carries a high mortality. Utilizing a previously validated porcine model of sepsis-induced ARDS, we sought to refine our novel therapeutic technique of in vivo lung perfusion (IVLP). We hypothesized that 2 hours of IVLP would provide non-inferior lung rehabilitation compared to 4 hours of treatment. Adult swine (n = 8) received lipopolysaccharide to develop ARDS and were placed on central venoarterial extracorporeal membrane oxygenation. Animals were randomized to 2 vs 4 hours of IVLP. The left pulmonary vessels were cannulated to IVLP using antegrade Steen solution. After IVLP treatment, the left lung was decannulated and reperfused for 4 hours. Total lung compliance and pulmonary venous gases from the right lung (control) and left lung (treatment) were sampled hourly. Biochemical analysis of tissue and bronchioalveolar lavage was performed along with tissue histologic assessment. Throughout IVLP and reperfusion, treated left lung PaO2/FiO2 ratio was significantly higher than the right lung control in the 2-hour group (332.2 ± 58.9 vs 264.4 ± 46.5, P = 0.01). In the 4-hour group, there was no difference between treatment and control lung PaO2/FiO2 ratio (258.5 ± 72.4 vs 253.2 ± 90.3, P = 0.58). Wet-to-dry weight ratios demonstrated reduced edema in the treated left lungs of the 2-hour group (6.23 ± 0.73 vs 7.28 ± 0.61, P = 0.03). Total lung compliance was also significantly improved in the 2-hour group. Two hours of IVLP demonstrated superior lung function in this preclinical model of sepsis-induced ARDS. Clinical translation of IVLP may shorten duration of mechanical support and improve outcomes.

Ex vivo lung perfusion in lung transplantation

Lung transplantation is an established life-saving intervention for patients with end-stage lung diseases. The success of lung transplantation mainly depends on the quality and function of the implanted donor lungs, which are frequently subject to brain-death-induced lung injuries and intensive care unit (ICU)-related complications before transplantation. Recent innovations, particularly the development of ex vivo lung perfusion (EVLP), in which donor lungs are ventilated and perfused under normothermic conditions outside the body, have allowed clinicians to more accurately assess the donor lung function prior to transplantation. Therefore, EVLP has been successfully translated into clinical practice with the expansion of the donor lung pool, leading to favorable post-transplant outcomes in a growing number of transplant centers worldwide. The EVLP system and techniques, following the Toronto protocol, have recently been applied for the assessment of extended criteria brain-death donors in clinical lung transplantation in Japan. The advancement of EVLP from organ assessment to organ treatment will be the next challenging stage not only to expand donor lung pool, but also to improve graft survival and long-term outcomes after transplantation.

Isolated Lung Perfusion in the Management of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality, and current management has a dramatic impact on healthcare resource utilization. While our understanding of this disease has improved, the majority of treatment strategies remain supportive in nature and are associated with continued poor outcomes. There is a dramatic need for the development and breakthrough of new methods for the treatment of ARDS. Isolated machine lung perfusion is a promising surgical platform that has been associated with the rehabilitation of injured lungs and the induction of molecular and cellular changes in the lung, including upregulation of anti-inflammatory and regenerative pathways. Initially implemented in an ex vivo fashion to evaluate marginal donor lungs prior to transplantation, recent investigations of isolated lung perfusion have shifted in vivo and are focused on the management of ARDS. This review presents current tenants of ARDS management and isolated lung perfusion, with a focus on how ex vivo lung perfusion (EVLP) has paved the way for current investigations utilizing in vivo lung perfusion (IVLP) in the treatment of severe ARDS.

Solid phase microextraction chemical biopsy tool for monitoring of doxorubicin residue during in vivo lung chemo-perfusion

Development of a novel in vivo lung perfusion (IVLP) procedure allows localized delivery of high-dose doxorubicin (DOX) for targeting residual micrometastatic disease in the lungs. However, DOX delivery via IVLP requires careful monitoring of drug level to ensure tissue concentrations of this agent remain in the therapeutic window. A small dimension nitinol wire coated with a sorbent of biocompatible morphology (Bio-SPME) has been clinically evaluated for in vivo lung tissue extraction and determination of DOX and its key metabolites. The in vivo Bio-SPME-IVLP experiments were performed on pig model over various (150 and 225 mg/m²) drug doses, and during human clinical trial. Two patients with metastatic osteosarcoma were treated with a single 5 and 7 μg/mL (respectively) dose of DOX during a 3-h IVLP. In both pig and human cases, DOX tissue levels presented similar trends during IVLP. Human lung tissue concentrations of drug ranged between 15 and 293 μg/g over the course of the IVLP procedure. In addition to DOX levels, Bio-SPME followed by liquid chromatography-mass spectrometry analysis generated 64 metabolic features during endogenous metabolite screening, providing information about lung status during drug administration. Real-time monitoring of DOX levels in the lungs can be performed effectively throughout the IVLP procedure by in vivo Bio-SPME chemical biopsy approach. Bio-SPME also extracted various endogenous molecules, thus providing a real-time snapshot of the physiology of the cells, which might assist in the tailoring of personalized treatment strategy.

A model to assess acute and delayed lung toxicity of oxaliplatin during in vivo lung perfusion

OBJECTIVES

To determine the dose-limiting toxicity of oxaliplatin chemotherapy delivered by in vivo lung perfusion (IVLP). To allow assessment of subacute toxicities, we aimed to develop a 72-hour porcine IVLP survival model.

METHODS

In total, 12 Yorkshire male pigs were used. Left lung IVLP was performed for 3 hours. At 72 hours postoperatively, computed tomography imaging of the lungs was performed before the pigs were killed. Lung physiology, airway dynamics, gross appearance, and histology were assessed before and during IVLP, at reperfusion, and when the pigs were euthanized. An accelerated titration dose-escalation study design was employed whereby oxaliplatin doses were sequentially doubled provided no clinically significant toxicity was observed, defined as an arterial partial pressure of oxygen to fraction of inspired oxygen ratio <300 mm Hg or severe acute lung injury on biopsy.

RESULTS

After an initial training phase, no mortality or adverse events related to the procedure were observed. There was no lung injury observed at the time of IVLP for any case. At sacrifice, clinically significant lung injury was observed at 80 mg/L oxaliplatin, with an arterial partial pressure of oxygen to fraction of inspired oxygen ratio of 112 mm Hg. Mild and subclinical lung injury was observed at 40 mg/L, with this dose being repeated to confirm safety.

CONCLUSIONS

A stable and reproducible porcine 3-day IVLP survival model was established that will allow toxicity assessment of agents delivered by IVLP. Oxaliplatin delivered by IVLP showed delayed-onset toxicity that was not apparent at the time of reperfusion, with a maximal-tolerated dose of 40 mg/L. This information will inform initiation of a clinical trial examining IVLP delivery of oxaliplatin at our institution.

Implementation of an experimental isolated lung perfusion model on surgically resected human lobes

Isolated lung perfusion (ILP) is an ideal model to study treatment effects on a variety of pathologies. As published research mostly relies on rejected donor lungs or animal organs, this study investigates the use of surgically resected human lobes as an alternative and novel model for personalized experimental research. Ten surgically resected lobes were perfused in acellular and normothermic condition. The indication for surgery was lung cancer. Perfusion and ventilation were adapted to the size of the lobes and both functional and metabolic parameters were assessed during ILP. Patients (age 67.5 y (59–81)|♀n = 3|♂n = 7) underwent anatomic pulmonary lobectomy. Ischemic time between arterial ligation and ILP was 226 minutes (161–525). Median duration of ILP was 135 (87–366) minutes. Gas exchange and mechanical respiratory parameters remained steady during ILP (pulmonary venous pO₂ 196(151–219) mmHg | peak AWP: 14.5(11–22) cmH₂O). Metabolism stayed constant during ILP (Glucose consumption: 1.86 mg/min/L_TLC (95%CI: −2.09 to −1.63) | lactate production: 0.005 mmol/min/ L_TLC (95%CI: 0.004 to 0.007)). ILP of surgically resected human lobes is a feasible and promising method. By maintaining a near physiological setting, this model may pave the way for future experimental lung research including cancer research, transplantation, physiology, pharmacology and mechanical ventilation.

In vivo lung perfusion rehabilitates sepsis-induced lung injury

BACKGROUND

Sepsis is the leading cause of lung injury in adults and can lead to acute respiratory distress syndrome (ARDS). Using a novel technique of isolated in vivo lung perfusion (IVLP), we hypothesized that normothermic IVLP will improve oxygenation and compliance in a porcine model of sepsis-induced lung injury.

METHODS

Mature adult swine (n = 8) were administered lipopolysaccharide (LPS; 50 μg/kg over 2 hours) via the external jugular vein, followed by sternotomy and central extracorporeal membrane oxygenation (ECMO) cannulation (right atrium to ascending aorta). The left pulmonary artery (inflow) and left superior and inferior pulmonary veins (outflow) were dissected out and cannulated to deliver isolated perfusion to the left lung. After 4 hours of normothermic IVLP with Steen solution, the left lung then underwent 4 hours of reperfusion after IVLP decannulation. Airway pressures and lung-specific pulmonary vein blood gases from the right lung (LPS control) and left lung (LPS + IVLP) of the same animal were compared.

RESULTS

All animals demonstrated a significant reduction in the ratio of partial pressure of oxygen in arterial blood (PaO₂)/fraction of inspired oxygen (FiO₂) (P/F ratio) and total lung compliance at 2 hours after the start of LPS infusion (mean, 469 ± 19.7 mm Hg vs 222.2 ± 21.4 mm Hg; P < .0001). After reperfusion, 6 animals (75%) exhibited improved lung function, allowing for ECMO decannulation. Lung-specific oxygenation was superior in the left lung after 4 hours of reperfusion (mean, 310.5 ± 54.7 mm Hg vs 201.1 ± 21.7 mm Hg; P = .01). Similarly, total lung compliance improved after IVLP of the left lung. The lung wet weight to dry weight ratio demonstrated reduced edema in rehabilitated left lungs (mean, 6.5 ± 0.3 vs 7.5 ± 0.4; P = .04).

CONCLUSIONS

IVLP successfully rehabilitated LPS-injured lungs compared to ECMO support alone in this preclinical porcine model.

Porcine pulmonary auto-transplantation for ex vivo therapy as a model for new treatment strategies

OBJECTIVES

Lung auto-transplantation is the surgical key step in experiments involving ex vivo therapy of severe or end-stage lung diseases. Ex vivo therapy has become a clinical reality because of systems such as the Organ Care System (OCS) Lung, which is the only commercially available portable lung perfusion system. However, survival experiments involving porcine lung auto-transplantation pose special surgical and anaesthesiological challenges. This current study was designed to describe the development of surgical techniques and aneasthesiological management strategies that facilitate lung auto-transplantation survival surgery including a follow-up period of 4 days.

METHODS

Left pneumonectomy was performed in 12 Mini-Lewe miniature pigs. After ex vivo treatment of the harvested lungs within the OCS Lung for 2 h, the lungs were retransplanted into the same animal (auto-transplantation). Four animals were used to develop the optimal techniques and establish an experimental protocol. According to the final protocol, eight additional animals were operated. The follow-up period was 4 days.

RESULTS

There were four severe intraoperative surgical complications [anatomical variant of the superior vena cava (two times), a complication related to the bronchial anastomosis and a complication related to the pulmonary arterial anastomosis]. The major postoperative problems were hyperkalaemia, prolonged recovery from anaesthesia and pulmonary oedema after reperfusion. Establishment of the surgical technique showed that using a pericardial tube to facilitate the anastomosis of the thin left superior pulmonary vein should be considered to prevent thrombosis. However, routine use of the patch technique to construct venous and arterial anastomoses is not necessary. Furthermore, traction on the venous anastomoses can be avoided by performing the bronchial anastomosis first.

CONCLUSIONS

Lung auto-transplantation is a feasible experimental model for ex vivo therapy of lung diseases and is applicable for experimental questions concerning human lung transplantation.

Novel Technologies for Isolated Lung Perfusion: Beyond Lung Transplant

Isolated lung perfusion (ILP) has been examined and developed in lung transplantation and thoracic oncology research. In lung transplantation, ILP has been used to assess physiologic integrity of donor lungs after removal from the donor, and it has also been proposed as a method for active treatment and repair of injured unsuitable donor organs ex vivo. ILP is attractive as a concept to deliver high-dose chemotherapy to treat pulmonary metastatic disease, referred to as in vivo lung perfusion. This article focuses on the rationale, technical aspects, and experimental and clinical experience of in vivo lung perfusion. A perspective on the future application of these techniques is described.