Rat Lung Transplantation Research Articles

Angiotensin-converting enzyme 2 activation attenuates inflammation and oxidative stress in brain death donor followed by rat lung transplantation

Brain death (BD) provides most of the donor organs destined for lung transplantation (LTx). However, the organs may be affected by inflammatory and oxidative processes. Based on this, we hypothesize that the angiotensin-converting enzyme 2 (ACE2) activation can reduce the lung injury associated with LTx. 3 h after BD induction, rats were injected with saline (BD group) or an ACE2 activator (ACE2a group; 15 mg/kg-1) and kept on mechanical ventilation for additional 3 h. A third group included a control ventilation (Control group) prior to transplant. After BD protocol, left LTx were performed, followed by 2 h-reperfusion. ACE2 activation was associated with better oxygenation after BD management (p = 0.01), attenuating edema (p = 0.05) followed by the reduction in tissue resistance (p = 0.01) and increase of respiratory compliance (p = 0.02). Nrf2 expression was also upregulated in the ACE2a group (p = 0.03). After transplantation, ACE2a group showed lower levels of TNF-α (p = 0.02), IL-6 (p = 0.001), IL-1β (p = 0.01), ROS (p = 0.004) and MDA (p = 0.002), in addition to higher CAT activity (p = 0.04). In conclusion, our study suggests that ACE2 activation improves anti-inflammatory and antioxidant activity in a model of LTx.

L-Alanyl-L-Glutamine Alleviated Ischemia-Reperfusion Injury and Primary Graft Dysfunction in Rat Lung Transplants.

Concern of ischemia-reperfusion injury reduces utilization of donor lungs. We hypothesized adding L-alanyl-L-glutamine (L-AG) to preservation solution may protect donor lungs from ischemia-reperfusion injury through its multiple cytoprotective effects. A lung transplantation cell culture model was used on human lung epithelial cells and pulmonary microvascular endothelial cells, and the effects of adding different concentrations of L-AG on basic cellular function were tested. Rat donor lungs were preserved at 4 °C with 8 mmol/L L-AG for 12 h followed by 4 h reperfusion or monitored for 3 d. Lung function, lung histology, inflammation, and cell death biomarker were tested. Computerized tomography scan was used and metabolomic analysis was performed on lung tissues. Cold preservation with L-AG improved cell viability and inhibited apoptosis in cell culture. Rat donor lungs treated with L-AG during cold storage showed decreased peak airway pressure, higher dynamic compliance and oxygenation ability, reduced lung injury, apoptosis, and oxidative stress during reperfusion. L-AG treatment significantly changed 130 metabolites during reperfusion, with enhanced amino acid biosynthesis and tricarboxylic acid cycle. Furthermore, cold storage with L-AG decreased primary graft dysfunction grade, improved oxygenation, reduced pulmonary atelectasis, sign of infection, and pneumothorax in a rat left lung transplant 3-d survival model. Adding L-AG to cold preservation solution reduced lung injury and alleviated primary graft dysfunction by inhibiting inflammation, oxidative stress, and cell death with modified metabolic activities.

A novel rat lung transplantation model using venoarterial extracorporeal membrane oxygenation support

ObjectivesExtracorporeal membrane oxygenation (ECMO) has become an important life support technique during lung transplantation. We aimed to develop a rat model for lung transplantation using venoarterial (VA) ECMO support. MethodsAdult male Sprague-Dawley rats weighing 400 to 450 g were used in this study. ECMO circuits were created by obtaining venous access from the femoral vein with subsequent extracorporeal oxygen exchange, which was then returned to the circulatory system through the left carotid artery (ie, VA-ECMO). Simultaneously, the donor lungs were retrieved and immersed in cold, low-potassium dextran lung preservation solution. Orthotopic left lung transplantation supported by VA-ECMO was performed. Thereafter, a respiratory failure rat model was constructed using ventilation with a hypoxic and hypercapnic gas mixture, consisting of 6% oxygen, 8% carbon dioxide, and 86% nitrogen, before lung transplantation. Similarly, left lung transplantation supported by VA-ECMO was performed in rats with respiratory failure. Arterial blood gas levels were measured at designated time points throughout the experiment. ResultsWe found that VA-ECMO provided sufficient oxygenation and carbon dioxide removal to allow for smooth left lung transplantation in healthy rats and those with respiratory failure. ConclusionsWe established a rat model for lung transplantation using VA-ECMO. Left lung transplantation using VA-ECMO support is also feasible and safe in rat models of respiratory failure. These models provide efficient and economical models for translational medicine for lung transplantation using ECMO. Moreover, it will be invaluable to evaluate the physiological and pathophysiological roles of ECMO during lung transplantation.

Hyperacute experimental model of rat lung transplantation using a coronary shunt cannula.

Lung transplantation is a well-established treatment of end-stage lung disease. A rodent model is an inexpensive way to collect biological data from a living model after lung transplantation. However, mastering the surgical technique takes time owing to the small organ size. To conduct rat lung transplantation using a shunt cannula (SC) or modified cannula (MC) and assess their efficacy. Rat lung transplantation was performed in 11 animals in the SC group and 12 in the MC group. We devised a method of rat lung transplantation using a coronary SC for coronary artery bypass surgery as an anastomosis of pulmonary arteriovenous vessels and bronchioles. The same surgeon performed all surgical procedures in the donor and recipient rats without using a magnifying glass. The success rate of lung transplantation, operating time, and PaO2 values were compared after 2-h reperfusion after transplantation. Ten and 12 lungs were successfully transplanted in the SC and MC groups, respectively. In the SC group, one animal had cardiac arrest within 1 h after reperfusion owing to bleeding during pulmonary vein anastomosis. The operating time for the removal of the heart-lung block from the donor and preparation of the left lung graft was 26.8 ± 2.3 and 25.7 ± 1.3 min in the SC and MC groups, respectively (P = 0.21). The time required for left lung transplantation in the recipients was 37.5 ± 2.8 min and 35.9 ± 1.4 min in the SC and MC groups, respectively (P = 0.12). PaO2 values at 2 h after reperfusion were 456.2 ± 25.5 and 461.2 ± 21.5 mmHg in the SC and MC groups, respectively (P = 0.63), without difference between the groups. A hyperacute rat lung transplantation model using a coronary SC was created using a simple technique. The MC was inexpensive, easy to prepare, and simple to operate.

Donor Inhalation of Nebulized Dexmedetomidine Alleviates Ischemia-Reperfusion Injury in Rat Lung Transplantation

Introduction: The occurrence of lung ischemia-reperfusion injury (LIRI) after lung transplantation results in primary graft dysfunction (PGD) in more than 50% of cases, which seriously affects the prognosis of recipients. Currently, donor lung protection is the focus of research on improving graft survival in lung transplant recipients. Dexmedetomidine (Dex) is a widely used general anesthesia adjuvant in clinical practice to alleviate ischemia-reperfusion injury in the lungs, liver, heart, kidneys, and brain. However, intravenous infusion of Dex can cause negative effects on the cardiovascular system. Inhaling nebulized Dex can directly act on the alveolar tissue and alleviate its cardiovascular inhibitory effect by reducing drug intake. This study aimed to investigate the effect of donor nebulized Dex inhalation on LIRI after lung transplantation in rats. Methods: We randomly divided the male Sprague-Dawley rats into donor rats and recipient rats, and allowed the donor rats to inhale nebulized Dex or physiological saline 15 min before surgery. The donor lung was refrigerated for 8 h before each single-lung transplant. After 2 h of reperfusion of the transplanted lung, serum and transplanted lung tissue were collected. The wet-to-dry weight ratio of the lung tissue was measured, arterial blood gas was detected, and histopathology changes, oxidative stress, inflammatory reactions, and apoptosis were evaluated. Results: Pretransplant inhalation of Dex through the donor’s lung reduced the injury of the transplanted lung, increased the levels of malondialdehyde and myeloperoxidase, and decreased the levels of superoxide dismutase and glutathione in the lung tissue. Moreover, nebulized Dex inhalation of the donor lung inhibited LIRI-induced tumor necrosis factor-α, interleukin-6, and inducible nitric oxide synthase expression and also suppressed nuclear factor kappa B phosphorylation. Nebulized Dex inhalation reduced the rate of cell apoptosis in the transplanted lung tissue by inhibiting the upregulation of Bax, downregulation of Bcl-2, and increase in caspase-3 lysis caused by LIRI. Conclusion: Inhalation of atomized Dex is a potential donor lung protection strategy, which can be used to reduce LIRI after lung transplantation and may be helpful to improve the occurrence of PGD and prognosis of lung transplant recipients.

(177) - AAV Delivery of PD-L1 with Concomitant CTLA-4 Immunoglobulin Attenuates Acute Cellular Rejection in a Rat Lung Transplant Model

(177) - AAV Delivery of PD-L1 with Concomitant CTLA-4 Immunoglobulin Attenuates Acute Cellular Rejection in a Rat Lung Transplant Model

Metformin alleviates lung ischemia–reperfusion injury in a rat lung transplantation model

Background: Lung ischemia–reperfusion injury (LIRI) is among the complications observed after lung transplantation and is associated with morbidity and mortality. Preconditioning of the donor lung before organ retrieval may improve organ quality after transplantation. We investigated whether preconditioning with metformin (Met) ameliorates LIRI after lung transplantation. Methods: Twenty Lewis rats were randomly divided into the sham, LIRI, and Met groups. The rats in the LIRI and Met groups received saline and Met, respectively, via oral gavage. Subsequently, a donor lung was harvested and kept in cold storage for 8 h. The LIRI and Met groups then underwent left lung transplantation. After 2 h of reperfusion, serum and transplanted lung tissues were examined. Results: The partial pressure of oxygen (PaO2) was greater in the Met group than in the LIRI group. In the Met group, wet-to-dry (W/D) weight ratios, inflammatory factor levels, oxidative stress levels and apoptosis levels were notably decreased. Conclusions: Met protects against ischemia–reperfusion injury after lung transplantation in rats, and its therapeutic effect is associated with its anti-inflammatory, antioxidative, and antiapoptotic properties.

Protective Effect of Calpain Inhibition During Cold Ischemia on Ischemia-reperfusion Injury After Lung Transplantation.

Necroptosis, one of the types of regulated necrosis, causes ischemia-reperfusion (IR) lung injury. N-acetyl-leucyl-leucyl-norleucinal (ALLN), a calpain inhibitor, is known to attenuate necroptosis and apoptosis, and the purpose of this study was to evaluate the protective effect of ALLN during cold ischemia against IR injury in a rat lung transplant model. Male Lewis rats (250-350 g) were divided into 3 groups: sham group (n = 4), nontransplantation; control group (n = 8), transplantation with IR lung injury; and ALLN group (n = 8), transplantation with IR lung injury/ALLN. Rats in the sham group underwent a simple thoracotomy, and the remaining 2 groups of rats underwent an orthotopic left lung transplant. Cold ischemic time was 15 h. After 2 h of reperfusion, physiological function, inflammatory cytokine expression, pathway activation, and the degrees of necroptosis and apoptosis were evaluated. Lung gas exchange (PaO 2 /FiO 2 ) was significantly better, and pulmonary edema was significantly improved in the ALLN group compared with the control group ( P = 0.0009, P = 0.0014). Plasma expression of interleukin-1β was significantly lower in the ALLN group than in the control group ( P = 0.0313). The proportion of necroptotic and apoptotic cells was significantly lower in the ALLN group than in the control group ( P = 0.0009), whereas the proportion of apoptotic cells remained unchanged ( P = 0.372); therefore, the calpain inhibitor was thought to suppress necroptosis. The administration of ALLN during cold ischemia appears to improve IR lung injury in a lung transplant animal model via the inhibition of necroptosis.

Effect of β-Nicotinamide Adenine Dinucleotide on Acute Allograft Rejection After Rat Lung Transplantation.

Rat single-lung transplantation was performed in 2 groups (n = 8 per group), using Brown-Norway donors and major histocompatibility complex-mismatched Lewis recipients. Recipients of the NAD+ group received 1000 mg/kg NAD+ intraperitoneally before transplantation and daily thereafter until euthanasia, whereas the control group received saline solution. At autopsy on day 5, blood samples were analyzed and the lung allograft was assessed by bronchioalveolar lavage, histology, and immunochemistry. The NAD+ group maintained an intact compliant lung tissue, a strong trend of lower acute cellular rejection (A3 versus A3-A4) and significantly less lymphocytic bronchiolitis (B0-B2R versus B1R-Bx). In addition, a trend of fewer alveolar CD68+ macrophages and significantly fewer interstitial CD163+ macrophages was observed. Bronchoalveolar lavage in the NAD+ group showed significantly fewer proinflammatory cytokines interleukin (IL)-6, IL-13, TNFα, and a protective IL-6/IL-10-ratio. In blood samples, we observed significantly fewer neutrophils, and proinflammatory GRO/KC in the NAD+ group. NAD+ might be a promising substance in prevention of acute allograft rejection in lung transplantation.

Timing of Mesenchymal Stromal Cell Therapy Defines its Immunosuppressive Effects in a Rat Lung Transplantation Model

Cell therapy using mesenchymal stromal cells (MSCs) is being studied for its immunosuppressive effects. In organ transplantation, the amount of MSCs that accumulate in transplanted organs and other organs may differ depending on administration timing, which may impact their immunosuppressive effects. In vitro, adipose-derived mesenchymal stem cells (ADMSCs) suppress lymphocyte activation under cell-to-cell contact conditions. However, in vivo, it is controversial whether ADMSCs are more effective in accumulating in transplanted organs or in secondary lymphoid organs. Herein, we aimed to investigate whether the timing of ADMSC administration affects its immunosuppression ability in a rat lung transplantation model. In the transplantation study, rats were intramuscularly administered half the usual dose of tacrolimus (0.5 mg/kg) every 24 h after lung transplantation. ADMSCs (1 × 106) were administered via the jugular vein before (PreTx) or after (PostTx) transplantation. Cell tracking using quantum dots was performed. ADMSCs accumulated predominantly in the lung and liver; fewer ADMSCs were distributed in the grafted lung in the PreTx group than in the PostTx group. The rejection rate was remarkably low in the ADMSC-administered groups, particularly in the PostTx group. Serum tumor necrosis factor-α (TNF-α), interferon-γ, and interleukin (IL)-6 levels showed a greater tendency to decrease in the PreTx group than in the PostTx group. The proportion of regulatory T cells in the grafted lung 10 days after transplantation was higher in the PostTx group than in the PreTx group. PostTx administration suppresses rejection better than PreTx administration, possibly due to regulatory T cell induction by ADMSCs accumulated in the transplanted lungs, suggesting a mechanism different from that in heart or kidney transplantation that PreTx administration is more effective than PostTx administration. These results could help establish cell therapy using MSCs in lung transplantation.

Donor and Recipient Adipose-Derived Mesenchymal Stem Cell Therapy for Rat Lung Transplantation

Mesenchymal stem cells (MSCs) are beginning to be proven as immunosuppressant in the field of organ transplantation. However, the effects of MSC origin (donor or recipient) on immunosuppression are not clear. Hence, we investigated the effects of recipient and donor adipose-derived MSCs (ADMSCs) on immunosuppression in a rat lung transplantation model. Subjects were divided into no treatment, tacrolimus administration, recipient ADMSC administration, donor ADMSC administration, and mixed donor and recipient ADMSC administration groups. ADMSC-administered groups were also treated with tacrolimus. Histologic study, immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay, and polymerase chain reaction were used for various analyses. Fluorescently labeled ADMSCs were predominant in the grafted donor lung, but not in the recipient lung, on day 5. On day 7, the pathologic rejection grades of the grafted donor lung were significantly lower in the ADMSC-administered groups (P < .05) and did not differ among these groups. Although serum hepatocyte growth factor and vascular endothelial growth factor levels did not differ among the groups, interleukin 10 level was slightly higher in the ADMSC-administered groups. The numbers of infiltrating regulatory T cells in the grafted lung were significantly higher in the ADMSC-administered groups (P < .05) but did not differ with cell origin. Transcriptional analysis suggested interleukin 6 suppression to be the main overlapping immunosuppressive mechanism, regardless of origin. Therefore, a donor or recipient origin may not influence the immunosuppressive efficacy of ADMSCs in our rat lung transplantation model. Collectively, the results indicate that allogenic ADMSCs, regardless of their origin, may exert similar immunosuppressive effects in clinical organ transplantation.

Donor extracellular vesicle trafficking via the pleural space represents a novel pathway for allorecognition after lung transplantation

Restoration of lymphatic drainage across the bronchial anastomosis after lung transplantation requires several weeks. As donor antigen and antigen presenting cell trafficking via lymphatics into graft-draining lymph nodes is an important component of the alloresponse, alternative pathways must exist that account for rapid rejection after pulmonary transplantation. Here, we describe a novel allorecognition pathway mediated through donor extracellular vesicle (EV) trafficking to mediastinal lymph nodes via the pleural space. Pleural fluid collected early after lung transplantation in rats and humans contains donor-specific EVs. In a fully MHC mismatched rat model of lung transplantation, we demonstrate EVs carrying donor antigen preferentially accumulate in mediastinal lymph nodes and colocalize with MHC II expressing cells within 4h of engraftment. Injection of allogeneic EVs into pleural space of syngeneic lung transplant recipients confirmed their selective trafficking to mediastinal lymph nodes and resulted in activation of T cells in mediastinal, but not peripheral lymph nodes. Thus, we have uncovered an alternative pathway of donor antigen trafficking where pulmonary EVs released into the pleural space traffic to locoregional lymph nodes via pleural lymphatics. This pathway obviates the need for restoration of lymphatics across the bronchial anastomosis for trafficking of donor antigen to draining lymph nodes.

Improvement of surgical techniques for orthotopic single lung transplantation in rats.

BackgroundAlthough orthotopic single lung transplantation in rats has long been established, this model is still highly challenging. Therefore, we made several modifications in anesthesia, lung extraction, vascular clamp, and transplantation procedures for this model.MethodsFifty cases of rat left lung transplantation were performed using traditional procedures and modified surgical techniques, respectively. Two hundred Sprague Dawley male rats, half as donors and half as recipients, were randomized equally to the two groups. The modifications included orotracheal intubation via a video laryngoscope, retrograde perfusion following anterograde perfusion, a Rummel tourniquet for the occlusion of pulmonary vessels, flushing the vessels and cuffs before anastomosis with heparin, and a simple pleural drainage. The surgical time, warm and cold ischemia time, vascular complications, and survival rate on postoperative day seven were compared between the two groups.ResultsThe modified surgical techniques significantly reduced the surgical duration (35.7 vs. 46.3 min, P<0.01), warm ischemia time (16.3 vs. 28.8 min, P<0.01), and vascular complications (2% vs. 16%, P=0.04). Moreover, the survival rate on postoperative day 7 was higher in the improved surgical techniques group (96% vs. 80%, P=0.03).ConclusionsWe described the improvement of surgical techniques for orthotopic single lung transplantation in rats, which could shorten anastomoses time, reduce vascular complications, and improve survival rate.

Noninvasive monitoring of allograft rejection in a rat lung transplant model: Application of machine learning-based 18F-fluorodeoxyglucose positron emission tomography radiomics.

Standardized uptake values (SUVs) derived from 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) are valuable but insufficient for detecting lung allograft rejection (AR). Using a rat lung transplantation (LTx) model, we investigated correlations of AR with the SUVmax and PET-derived radiomics and further evaluated the performance of machine learning (ML)-based radiomics for monitoring AR. LTx was performed on 4 groups of rats: isograft, allograft-cyclosporinecontinuous (CsAcont), allograft-CsAdelayed, and allograft-CsA1week. Each rat underwent 18F-FDG PET at week 3 or 6. The SUVmax and radiomic features were extracted from the PET images. Least absolute shrinkage and selection operator regression was used to construct a radiomics score (Rad-score). Ten modeling algorithms with 7 feature selection methods were performed to develop 70 radiomics models (49 ML models and 21 logistic regression models) for monitoring AR, validated using the bootstrap method. In total, 837 radiomic features were extracted from each PET image. The SUVmax and Rad-score showed significant positive correlations with histopathology (p < .05). The area under the curve (AUC) of SUVmax for detecting AR was 0.783. The median AUC of ML models was 0.921, which was superior to that of logistic regression models (median AUC, 0.721). The optimal ML model using a random forest modeling algorithm with random forest feature selection method exhibited the highest AUC of 0.982 (95% confidence interval, 0.875-1.000) in all models. SUVmax provided a good correlation with AR, but ML-based PET radiomics further strengthened the power of 18F-FDG PET functional imaging for monitoring AR in LTx.

Development of Total Lymphoid Irradiation (TLI)-Dedicated Shielding and Image-Guided System and Dose Evaluation Using 3D-Printed Rat Phantom.

PurposeThe purpose of this study is to propose a technique for delivering accurate doses in an image-guided system by developing an experimental setup optimized for total lymphoid irradiation (TLI) in rat lung transplantation.Materials and MethodsIn this study, a position-controlled shielding system was developed, and the dose was quantitatively evaluated using a 3D rat phantom and Gafchromic EBT3 film. In addition, we made our own image-guided system that allows the position of the rat and the shielding system to be confirmed during TLI.ResultsAs a result of using the position-controlled shielding system, it was found that the doses to the head and lungs were reduced by 93.1 and 87.4%, respectively, of the prescribed doses. In addition, it was shown that the position of the shielding system can be easily confirmed by using the image guidance system.ConclusionA shielding apparatus that can control dose delivery according to the size of the rat can optimize the dose for TLI in rat lung transplantation.

Reduction of Donor Mononuclear Phagocytes During Ex Vivo Lung Perfusion Attenuates Ischemia-Reperfusion Injury in a Rat Lung Transplantation Model

<h3>Purpose</h3> Mononuclear phagocytes (MPs) play a key role in post-lung transplantation (LTx) ischemia-reperfusion injury (IRI). Clodronate-liposome is a promising drug for the depletion of MPs. We hypothesized that the administration of clodronate-liposome into the perfusate during <i>ex vivo</i> lung perfusion (EVLP) could reduce MPs and attenuate IRI in a rat LTx model. <h3>Methods</h3> Lewis rat lungs were flushed with Perfadex® solution and stored for 15 h at 4°C. In Experiment I, grafts were allocated to two groups: control and clodronate (n = 5 each). In the clodronate group, 3 mL of clodronate-liposome was administered into the perfusate before EVLP. After 4 h of EVLP, the amounts of MPs in the perfusate and digested lung tissue were measured via flow cytometry. In Experiment II, grafts were similarly allocated to two groups: control and clodronate (n = 6 each). After 4 h of EVLP, left lungs were transplanted and reperfused for 2 h. Lung function was then evaluated, and samples were collected. The Mann-Whitney U test was used for comparing the two groups. Repeated measures analysis of variance was used for comparing data obtained during EVLP. <h3>Results</h3> In Experiment I, the amounts of MPs were significantly reduced in the clodronate group (<i>P</i>=0.008, Figure 1A). In Experiment II, compliance and vascular resistance during EVLP were significantly better in the clodronate group than in the control group (<i>P</i><0.001 and <i>P</i><0.001, respectively). Two hours after reperfusion, the PaO₂/FiO₂ ratio from the pulmonary vein was significantly higher in the clodronate group (<i>P</i>=0.015, Figure 1B), whereas the wet-to-dry weight ratio was significantly lower (<i>P</i>=0.026). Regarding scoring of histological findings, less lung injury was observed in the clodronate group than in the control group (<i>P</i>=0.013). <h3>Conclusion</h3> The administration of clodronate-liposome into the perfusate during EVLP demonstrated significant attenuation of MPs in the donor lungs and IRI post-LTx.

Right lung transplantation with a left-to-right inverted anastomosis in a rat model

ObjectiveRight lung transplantation in rats has been attempted occasionally, but the technical complexity makes it challenging to apply routinely. Additionally, basic research on inverted lobar lung transplantation is scarce because of the lack of a cost-effective experimental model. We first reported right lung transplantation in a rat model using left-to-right inverted anastomosis to imitate the principle of clinically inverted lung transplantation. MethodsRight lung transplantation was performed in 10 consecutive rats. By using a 3-cuff technique, the left lung of the donor rat was implanted into the right thoracic cavity of the recipient rat. The rat lung graft was rotated 180° along the vertical axis to achieve anatomic matching of right hilar structures. Another 10 consecutive rats had received orthotopic left lung transplantation as a control. ResultsAll lung transplantation procedures were technically successful without intraoperative failure. One rat (10%) died of full pulmonary atelectasis after right lung transplantation, whereas all rats survived after left lung transplantation. No significant difference was observed in heart-lung block retrieval (8.6 ± 0.8 vs 8.4 ± 0.9 minutes), cuff preparation (8.3 ± 0.9 vs 8.7 ± 0.9 minutes), or total procedure time (58.2 ± 2.6 vs 56.6 ± 2.1 minutes) between the right lung transplantation and standard left lung transplantation groups (P > .05), although the cold ischemia time (14.2 ± 0.9 vs 25.5 ± 1.7 minutes) and warm ischemia time (19.8 ± 1.5 vs 13.7 ± 1.8 minutes) were different (P < .001). ConclusionsRight lung transplantation with a left-to-right inverted anastomosis in a rat model is technically easy to master, expeditious, and reproducible. It can potentially imitate the principle of clinically inverted lung transplantation and become an alternative to standard left lung transplantation.

A Rat Lung Transplantation Model of Warm Ischemia/Reperfusion Injury: Optimizations to Improve Outcomes.

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods for choosing appropriate cuff sizes for the pulmonary vein (PV), pulmonary artery (PA), or bronchus (Br) are varied, thus making the determination of proper cuff size during rat lung transplantation an exercise of trial and error. By standardizing the cuffing technique to use the smallest effective cuff appropriate for the size of the vessel or bronchus, one can make the transplantation procedure safer, faster, and more successful. Since diameters of the PV, PA, and Br are related to the body weight of the rat, we present a strategy to choosing an appropriate size using a weight-based guide. Since lung volume is also related to body weight, we recommend that this relationship should also be considered when choosing the proper volume of air for donor lung inflation during warm ischemia as well as for the proper volume of PBS to be instilled during bronchoalveolar lavage (BAL) fluid collection. We also describe methods for 4th intercostal space dissection, wound closure, and sample collection from both the native and transplanted lobes.

A Rat Lung Transplantation Model of Warm Ischemia/Reperfusion Injury: Optimizations to Improve Outcomes

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods for choosing appropriate cuff sizes for the pulmonary vein (PV), pulmonary artery (PA), or bronchus (Br) are varied, thus making the determination of proper cuff size during rat lung transplantation an exercise of trial and error. By standardizing the cuffing technique to use the smallest effective cuff appropriate for the size of the vessel or bronchus, one can make the transplantation procedure safer, faster, and more successful. Since diameters of the PV, PA, and Br are related to the body weight of the rat, we present a strategy to choosing an appropriate size using a weight-based guide. Since lung volume is also related to body weight, we recommend that this relationship should also be considered when choosing the proper volume of air for donor lung inflation during warm ischemia as well as for the proper volume of PBS to be instilled during bronchoalveolar lavage (BAL) fluid collection. We also describe methods for 4th intercostal space dissection, wound closure, and sample collection from both the native and transplanted lobes.

Application of Radiomics Based on 18F-fluorodeoxyglucose Positron Emission Tomography for Predicting of Allograft Rejection in a Rat Lung Transplantation Model

Purpose The 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) has the potential of a noninvasive method for lung allograft rejection (AR) detection, but the accuracy is unsatisfied. Radiomics has been shown to improve the accuracy of diagnosis and treatment response assessment in other fields. Using a rat model of lung transplantation (LTx), we aim to assess the correlation between 18F-FDG PET-based radiomics and lung AR, and compare the predictive power to standardized uptake values (SUVs). Methods Twenty-eight rats were included in three groups at week 3 (Syngeneic, Immunosuppression and AR) and four groups (Syngeneic, Immunosuppression, Hybrid and AR) at week 6. The PyRadiomics package was used to extract the radiomic features from the PET images. The least absolute shrinkage and selection operator (LASSO) algorithm was used to establish the AR-related radiomics signature. A radiomics signature-based nomogram was created to visualize the outcome prediction. We compared the predictive performance of the radiomics signature and SUVs using the area under the receiver operator characteristic curve (AUC). Histopathology results served as a reference. Results From the PET images, a total of 110 radiomic features were extracted, and most of the radiomic features had an acceptable correlation with the histopathological results (P Conclusion The 18F-FDG PET-based radiomics is a potential noninvasive and accurate method to predict lung AR in a rat model of an orthotopic LTx. The radiomics signature showed a better predictive power than SUVs.