Monday’s Lillehei Forum highlighted basic research

 

The Lillehei Forum is a series of presentations on basic research by residents in the field of cardiothoracic surgery.

A targeted near-infrared contrast agent specific for lung adenocarcinomas was assessed for effectiveness during intraoperative molecular imaging (IMI) in animal models. Use of the contrast agent proved significantly more effective at detecting positive margins than did surgery alone, according to a study presented by Jarrod D. Predina, MD.

Initial human experiences with IMI for NSCLC using a fluorescent contrast agent have been limited by technical hurdles including high background noise in inflammatory tissues and low signal output, according to Dr. Predina. As an alternative, he and his colleagues at the University of Pennsylvania hypothesized that a targeted near-infrared contrast agent specific for lung adenocarcinomas would improve sensitivity and specificity during surgery.

Using a mouse surgical model of non–small cell lung cancer (NSCLC) that recapitulates local and systemic post-operative recurrences, Dr. Predina and his colleagues at the University of Pennsylvania injected 140 mice intravenously prior to resection with a near-infrared imaging agent (OTL0038). This agent is specific for pulmonary adenocarcinomas due to its high affinity binding of the folate receptor alpha. Tumor-bearing mice were randomized to surgery with or without IMI. Suspicious residual disease was resected and analyzed by immunohistochemistry, flow cytometry, and immunofluorescence. Based on this data, OTL0038 was tested in a pilot study of five canines with spontaneously occurring lung cancer.

In a local recurrence model system, of 80 mice assessed, surgeons identified 10 positive margins in those randomized to imaging with IMI vs. three positive margins in mice undergoing surgery alone, a significant difference. In systemic recurrence models (60 mice), the mean number of pulmonary nodules located with IMI was 7.2 vs. 3.4 in controls, also a significant difference, according to Dr. Predina.

In five canines with a presumed diagnosis of NSCLC, no toxicity was observed. Four of five canines had fluorescent tumors; the non-fluorescing tumor was discovered to be a metastatic mammary tumor on final pathologic analysis. In one canine, an otherwise undetectable 8-mm pulmonary adenocarcinoma was discovered with IMI.

“Our data suggest that a targeted near-infrared contrast agent may improve IMI technology. Ultimately, this will enable accurate identification of residual disease that may otherwise be overlooked. These results are the basis of an ongoing phase I human trial,” concluded Dr. Predina.

The complexity of the lung has limited the prospects of bioengineering strategies utilizing stem cells and fully decellularized or bioartificial scaffolds, according to Brandon A. Guenthart, MD, of Columbia University.

Dr. Guenthart recently reported on a new strategy to expand the potential pool of transplantable lungs using ex vivo lung perfusion (EVLP) coupled with a technique called cell replacement in porcine and human lungs. This strategy, rather than attempting to engineer a whole lung from an empty scaffold, aims to replace a sub-set of cells in targeted regions of damaged lungs to aid in the recovery of lung function or reverse a disease phenotype.

Using standard protocols, Dr. Guenthart and his colleagues procured human lungs rejected for transplantation on the basis of standard clinical criteria. Lungs were placed on a custom-built EVLP system, ventilated and perfused. Utilizing video bronchoscopy, real-time transpleural imaging, and a custom designed micro-catheter delivery and occlusion system, the team delivered a decellularization solution into targeted lung regions that resulted in the selective removal of airway epithelium.

Human airway epithelial cells or human-derived alveolar progenitor cells were labeled (with a quantum dot or a near-infrared dye) and delivered into decellularized lung regions. Following delivery, EVLP was continued for 4-6 hours to allow for cell engraftment. Lung wedge samples were collected at each time point for histologic analysis.

Following decellularization, hematoxylin and eosin staining confirmed removal of pseudostratified and columnar epithelium in proximal airways and removal of type I and II pneumocytes in the distal lung. Delivered cells were retained in the lung after EVLP and fixation, and cellular morphology and distribution within the alveoli indicated early engraftment.

“Bioengineering human lungs utilizing advanced therapeutic interventions such as cell replacement may help combat the critical shortage of transplantable lungs,” said Dr. Guenthart. “Additionally, in the future, targeted intervention and patient-specific cell replacement strategies may have translational applications in vivo and eliminate the need for transplantation in select patients,” he concluded.

J. Hunter Mehaffey, MD, of the University of Virginia, presented the results of a study that he and his colleagues performed in order to test an adjunct treatment to improve the results of ECMO for acute respiratory distress syndrome (ARDS). They developed a novel method of isolated in vivo lung perfusion (IVLP), which was able to successfully rehabilitate damaged lungs in a porcine model of sepsis-induced injury.

They used a previously validated porcine lung injury model of intravenous lipopolysaccharide (LPS) to induce a systemic inflammatory response and subsequent severe ARDS requiring ECMO support. A total of eight mature adult swine were administered LPS via the external jugular vein followed by sternotomy and central 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 isolate the left lung, which then underwent 4 hours normorthermic IVLP with Steen Solution followed by 4 hours of lung reperfusion after IVLP decannulation.

Dr. Mehaffey and his colleagues then compared the right (LPS control) and left lungs (LPS+IVLP) of the same animal.

All animals demonstrated a significant reduction in PaO₂/FiO₂ ratio and total lung compliance 2 hours after the start of LPS infusion. During IVLP, the left (treated) pulmonary vein oxygenation was superior to right (control) pulmonary vein oxygenation. After reperfusion and IVLP decannulation, six (75%) animals had improved lung function allowing for ECMO decannulation.

The left lung showed significant improvement of lung-specific oxygenation compared to the right control at 4 hours of reperfusion. Similarly, total lung compliance improved after targeted rehabilitation of the left lung, according to Dr. Mehaffey. In addition, the wet-to-dry ratio of lung tissue demonstrated significantly reduced edema in the rehabilitated left lungs compared to right controls.

Dr. Mehaffey and his colleagues concluded that IVLP may reduce the duration of ECMO and ventilator support resulting in major reduction in morbidity, mortality, and health care–related costs in patients with ARDS.

 

The Lillehei Forum is a series of presentations on basic research by residents in the field of cardiothoracic surgery.

A targeted near-infrared contrast agent specific for lung adenocarcinomas was assessed for effectiveness during intraoperative molecular imaging (IMI) in animal models. Use of the contrast agent proved significantly more effective at detecting positive margins than did surgery alone, according to a study presented by Jarrod D. Predina, MD.

Initial human experiences with IMI for NSCLC using a fluorescent contrast agent have been limited by technical hurdles including high background noise in inflammatory tissues and low signal output, according to Dr. Predina. As an alternative, he and his colleagues at the University of Pennsylvania hypothesized that a targeted near-infrared contrast agent specific for lung adenocarcinomas would improve sensitivity and specificity during surgery.

Using a mouse surgical model of non–small cell lung cancer (NSCLC) that recapitulates local and systemic post-operative recurrences, Dr. Predina and his colleagues at the University of Pennsylvania injected 140 mice intravenously prior to resection with a near-infrared imaging agent (OTL0038). This agent is specific for pulmonary adenocarcinomas due to its high affinity binding of the folate receptor alpha. Tumor-bearing mice were randomized to surgery with or without IMI. Suspicious residual disease was resected and analyzed by immunohistochemistry, flow cytometry, and immunofluorescence. Based on this data, OTL0038 was tested in a pilot study of five canines with spontaneously occurring lung cancer.

In a local recurrence model system, of 80 mice assessed, surgeons identified 10 positive margins in those randomized to imaging with IMI vs. three positive margins in mice undergoing surgery alone, a significant difference. In systemic recurrence models (60 mice), the mean number of pulmonary nodules located with IMI was 7.2 vs. 3.4 in controls, also a significant difference, according to Dr. Predina.

In five canines with a presumed diagnosis of NSCLC, no toxicity was observed. Four of five canines had fluorescent tumors; the non-fluorescing tumor was discovered to be a metastatic mammary tumor on final pathologic analysis. In one canine, an otherwise undetectable 8-mm pulmonary adenocarcinoma was discovered with IMI.

“Our data suggest that a targeted near-infrared contrast agent may improve IMI technology. Ultimately, this will enable accurate identification of residual disease that may otherwise be overlooked. These results are the basis of an ongoing phase I human trial,” concluded Dr. Predina.

The complexity of the lung has limited the prospects of bioengineering strategies utilizing stem cells and fully decellularized or bioartificial scaffolds, according to Brandon A. Guenthart, MD, of Columbia University.

Dr. Guenthart recently reported on a new strategy to expand the potential pool of transplantable lungs using ex vivo lung perfusion (EVLP) coupled with a technique called cell replacement in porcine and human lungs. This strategy, rather than attempting to engineer a whole lung from an empty scaffold, aims to replace a sub-set of cells in targeted regions of damaged lungs to aid in the recovery of lung function or reverse a disease phenotype.

Using standard protocols, Dr. Guenthart and his colleagues procured human lungs rejected for transplantation on the basis of standard clinical criteria. Lungs were placed on a custom-built EVLP system, ventilated and perfused. Utilizing video bronchoscopy, real-time transpleural imaging, and a custom designed micro-catheter delivery and occlusion system, the team delivered a decellularization solution into targeted lung regions that resulted in the selective removal of airway epithelium.

Human airway epithelial cells or human-derived alveolar progenitor cells were labeled (with a quantum dot or a near-infrared dye) and delivered into decellularized lung regions. Following delivery, EVLP was continued for 4-6 hours to allow for cell engraftment. Lung wedge samples were collected at each time point for histologic analysis.

Following decellularization, hematoxylin and eosin staining confirmed removal of pseudostratified and columnar epithelium in proximal airways and removal of type I and II pneumocytes in the distal lung. Delivered cells were retained in the lung after EVLP and fixation, and cellular morphology and distribution within the alveoli indicated early engraftment.

“Bioengineering human lungs utilizing advanced therapeutic interventions such as cell replacement may help combat the critical shortage of transplantable lungs,” said Dr. Guenthart. “Additionally, in the future, targeted intervention and patient-specific cell replacement strategies may have translational applications in vivo and eliminate the need for transplantation in select patients,” he concluded.

J. Hunter Mehaffey, MD, of the University of Virginia, presented the results of a study that he and his colleagues performed in order to test an adjunct treatment to improve the results of ECMO for acute respiratory distress syndrome (ARDS). They developed a novel method of isolated in vivo lung perfusion (IVLP), which was able to successfully rehabilitate damaged lungs in a porcine model of sepsis-induced injury.

They used a previously validated porcine lung injury model of intravenous lipopolysaccharide (LPS) to induce a systemic inflammatory response and subsequent severe ARDS requiring ECMO support. A total of eight mature adult swine were administered LPS via the external jugular vein followed by sternotomy and central 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 isolate the left lung, which then underwent 4 hours normorthermic IVLP with Steen Solution followed by 4 hours of lung reperfusion after IVLP decannulation.

Dr. Mehaffey and his colleagues then compared the right (LPS control) and left lungs (LPS+IVLP) of the same animal.

All animals demonstrated a significant reduction in PaO₂/FiO₂ ratio and total lung compliance 2 hours after the start of LPS infusion. During IVLP, the left (treated) pulmonary vein oxygenation was superior to right (control) pulmonary vein oxygenation. After reperfusion and IVLP decannulation, six (75%) animals had improved lung function allowing for ECMO decannulation.

The left lung showed significant improvement of lung-specific oxygenation compared to the right control at 4 hours of reperfusion. Similarly, total lung compliance improved after targeted rehabilitation of the left lung, according to Dr. Mehaffey. In addition, the wet-to-dry ratio of lung tissue demonstrated significantly reduced edema in the rehabilitated left lungs compared to right controls.

Dr. Mehaffey and his colleagues concluded that IVLP may reduce the duration of ECMO and ventilator support resulting in major reduction in morbidity, mortality, and health care–related costs in patients with ARDS.

 

The Lillehei Forum is a series of presentations on basic research by residents in the field of cardiothoracic surgery.

A targeted near-infrared contrast agent specific for lung adenocarcinomas was assessed for effectiveness during intraoperative molecular imaging (IMI) in animal models. Use of the contrast agent proved significantly more effective at detecting positive margins than did surgery alone, according to a study presented by Jarrod D. Predina, MD.

Initial human experiences with IMI for NSCLC using a fluorescent contrast agent have been limited by technical hurdles including high background noise in inflammatory tissues and low signal output, according to Dr. Predina. As an alternative, he and his colleagues at the University of Pennsylvania hypothesized that a targeted near-infrared contrast agent specific for lung adenocarcinomas would improve sensitivity and specificity during surgery.

Using a mouse surgical model of non–small cell lung cancer (NSCLC) that recapitulates local and systemic post-operative recurrences, Dr. Predina and his colleagues at the University of Pennsylvania injected 140 mice intravenously prior to resection with a near-infrared imaging agent (OTL0038). This agent is specific for pulmonary adenocarcinomas due to its high affinity binding of the folate receptor alpha. Tumor-bearing mice were randomized to surgery with or without IMI. Suspicious residual disease was resected and analyzed by immunohistochemistry, flow cytometry, and immunofluorescence. Based on this data, OTL0038 was tested in a pilot study of five canines with spontaneously occurring lung cancer.

In a local recurrence model system, of 80 mice assessed, surgeons identified 10 positive margins in those randomized to imaging with IMI vs. three positive margins in mice undergoing surgery alone, a significant difference. In systemic recurrence models (60 mice), the mean number of pulmonary nodules located with IMI was 7.2 vs. 3.4 in controls, also a significant difference, according to Dr. Predina.

In five canines with a presumed diagnosis of NSCLC, no toxicity was observed. Four of five canines had fluorescent tumors; the non-fluorescing tumor was discovered to be a metastatic mammary tumor on final pathologic analysis. In one canine, an otherwise undetectable 8-mm pulmonary adenocarcinoma was discovered with IMI.

“Our data suggest that a targeted near-infrared contrast agent may improve IMI technology. Ultimately, this will enable accurate identification of residual disease that may otherwise be overlooked. These results are the basis of an ongoing phase I human trial,” concluded Dr. Predina.

The complexity of the lung has limited the prospects of bioengineering strategies utilizing stem cells and fully decellularized or bioartificial scaffolds, according to Brandon A. Guenthart, MD, of Columbia University.

Dr. Guenthart recently reported on a new strategy to expand the potential pool of transplantable lungs using ex vivo lung perfusion (EVLP) coupled with a technique called cell replacement in porcine and human lungs. This strategy, rather than attempting to engineer a whole lung from an empty scaffold, aims to replace a sub-set of cells in targeted regions of damaged lungs to aid in the recovery of lung function or reverse a disease phenotype.

Using standard protocols, Dr. Guenthart and his colleagues procured human lungs rejected for transplantation on the basis of standard clinical criteria. Lungs were placed on a custom-built EVLP system, ventilated and perfused. Utilizing video bronchoscopy, real-time transpleural imaging, and a custom designed micro-catheter delivery and occlusion system, the team delivered a decellularization solution into targeted lung regions that resulted in the selective removal of airway epithelium.

Human airway epithelial cells or human-derived alveolar progenitor cells were labeled (with a quantum dot or a near-infrared dye) and delivered into decellularized lung regions. Following delivery, EVLP was continued for 4-6 hours to allow for cell engraftment. Lung wedge samples were collected at each time point for histologic analysis.

Following decellularization, hematoxylin and eosin staining confirmed removal of pseudostratified and columnar epithelium in proximal airways and removal of type I and II pneumocytes in the distal lung. Delivered cells were retained in the lung after EVLP and fixation, and cellular morphology and distribution within the alveoli indicated early engraftment.

“Bioengineering human lungs utilizing advanced therapeutic interventions such as cell replacement may help combat the critical shortage of transplantable lungs,” said Dr. Guenthart. “Additionally, in the future, targeted intervention and patient-specific cell replacement strategies may have translational applications in vivo and eliminate the need for transplantation in select patients,” he concluded.

J. Hunter Mehaffey, MD, of the University of Virginia, presented the results of a study that he and his colleagues performed in order to test an adjunct treatment to improve the results of ECMO for acute respiratory distress syndrome (ARDS). They developed a novel method of isolated in vivo lung perfusion (IVLP), which was able to successfully rehabilitate damaged lungs in a porcine model of sepsis-induced injury.

They used a previously validated porcine lung injury model of intravenous lipopolysaccharide (LPS) to induce a systemic inflammatory response and subsequent severe ARDS requiring ECMO support. A total of eight mature adult swine were administered LPS via the external jugular vein followed by sternotomy and central 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 isolate the left lung, which then underwent 4 hours normorthermic IVLP with Steen Solution followed by 4 hours of lung reperfusion after IVLP decannulation.

Dr. Mehaffey and his colleagues then compared the right (LPS control) and left lungs (LPS+IVLP) of the same animal.

All animals demonstrated a significant reduction in PaO₂/FiO₂ ratio and total lung compliance 2 hours after the start of LPS infusion. During IVLP, the left (treated) pulmonary vein oxygenation was superior to right (control) pulmonary vein oxygenation. After reperfusion and IVLP decannulation, six (75%) animals had improved lung function allowing for ECMO decannulation.

The left lung showed significant improvement of lung-specific oxygenation compared to the right control at 4 hours of reperfusion. Similarly, total lung compliance improved after targeted rehabilitation of the left lung, according to Dr. Mehaffey. In addition, the wet-to-dry ratio of lung tissue demonstrated significantly reduced edema in the rehabilitated left lungs compared to right controls.

Dr. Mehaffey and his colleagues concluded that IVLP may reduce the duration of ECMO and ventilator support resulting in major reduction in morbidity, mortality, and health care–related costs in patients with ARDS.