Overview of clinical lung transplantation

Factors Influencing the Attrition Rate of a 10-Week Multimodal Rehabilitation Program in Patients After Lung Transplant: A Neural Network Analysis

BACKGROUND/OBJECTIVES

Despite the effectiveness of exercise and nutritional interventions to improve aerobic capacity and quality of life in lung transplant (LT) recipients, their compliance is low. Strategies to reduce the high attrition rate (participants lost over time) is a major challenge. Artificial neural networks (ANN) may assist in the early identification of patients with high risk of attrition. The main objective of this study is to evaluate the usefulness of ANNs to identify prognostic factors for high attrition rate of a 10-week rehabilitation program after a LT.

METHODS

This prospective observational study included first-time LT recipients over 18 years of age. The main outcome for each patient was the attrition rate, which was estimated by the amount of missing data accumulated during the study. Clinical variables including malnutrition, sarcopenia, and their individual components were assessed at baseline. An ANN and regression analysis were used to identify the factors determining a high attrition rate.

RESULTS

Of the 41 participants, 17 (41.4%) had a high rate of attrition in the rehabilitation program. Only 23 baseline variables had no missing data and were included in the analysis, from which a low age-dependent body mass index (BMI) was the most important conditioning factor for a high attrition rate (p = 7.08 × 10-5), followed by end-stage respiratory disease requiring PT (p = 0.000111), low health-related quality-of-life (HRQoL) (p = 0.0009078), and low handgrip strength (p = 0.023).

CONCLUSIONS

The prevalence of high attrition rate in LT recipients is high. The profile of patients with a high probability of attrition includes those with chronic obstructive pulmonary disease, low BMI and handgrip strength, and reduced HRQoL.

Cold ischemia time alters cell-type specific senescence leading to loss of cellular integrity in mouse lungs

Purpose: Ischemia-reperfusion injury (IRI) is a major challenge in lung transplantation often causing graft dysfunction and chronic airway illnesses in recipients. To prevent potential transplant related complications, strict guidelines were put in place to choose viable donor lungs with minimal risk of IRI. These regulations deem most of the donor organs unfit for transplant which then are donated for research to understand the mechanisms of health and diseases in human. However, resected organs that are being transported undergo cold ischemia that can negatively affect the tissue architecture and other cellular functions under study. Thus, it is important to assess how cold ischemia time (CIT) affects the physiological mechanism. In this respect, we are interested in studying how CIT affects cellular senescence in normal aging and various pulmonary pathologies. We thus hypothesized that prolonged CIT exhibits cell-type specific changes in lung cellular senescence in mice. Methods: Lung lobes from C57BL/6J (n = 5-8) mice were harvested and stored in UW Belzer cold storage solution for 0, 4-, 9-, 12-, 24-, and 48-h CIT. Lung cellular senescence was determined using fluorescence (C12FdG) assay and co-immunolabelling was performed to identify changes in individual cell types. Results: We found a rapid decline in the overall lung cellular senescence after 4-h of CIT in our study. Co-immunolabelling revealed the endothelial cells to be most affected by cold ischemia, demonstrating significant decrease in the endothelial cell senescence immediately after harvest. Annexin V-PI staining further revealed a prominent increase in the number of necrotic cells at 4-h CIT, thus suggesting that most of the cells undergo cell death within a few hours of cold ischemic injury. Conclusions: We thus concluded that CIT significantly lowers the cellular senescence in lung tissues and must be considered as a confounding factor for mechanistic studies in the future.

Lung Progenitor and Stem Cell Transplantation as a Potential Regenerative Therapy for Lung Diseases

Chronic lung diseases are debilitating illnesses ranking among the top causes of death globally. Currently, clinically available therapeutic options capable of curing chronic lung diseases are limited to lung transplantation, which is hindered by donor organ shortage. This highlights the urgent need for alternative strategies to repair damaged lung tissues. Stem cell transplantation has emerged as a promising avenue for regenerative treatment of the lung, which involves delivery of healthy lung epithelial progenitor cells that subsequently engraft in the injured tissue and further differentiate to reconstitute the functional respiratory epithelium. These transplanted progenitor cells possess the remarkable ability to self-renew, thereby offering the potential for sustained long-term treatment effects. Notably, the transplantation of basal cells, the airway stem cells, holds the promise for rehabilitating airway injuries resulting from environmental factors or genetic conditions such as cystic fibrosis. Similarly, for diseases affecting the alveoli, alveolar type II cells have garnered interest as a viable alveolar stem cell source for restoring the lung parenchyma from genetic or environmentally induced dysfunctions. Expanding upon these advancements, the use of induced pluripotent stem cells to derive lung progenitor cells for transplantation offers advantages such as scalability and patient specificity. In this review, we comprehensively explore the progress made in lung stem cell transplantation, providing insights into the current state of the field and its future prospects.

[Outcomes of respiratory rehabilitation program in lung transplant recipients: a quasi experimental study]

INTRODUCTION

Lung transplant (LT) is the ultimate option for end-stage lung diseases. Malnutrition and sarcopenia, common in LT recipients, can be reversible with adequate exercise and nutrition. This study aims to assess changes in physical performance and aerobic capacity after a 10-week rehabilitation program (RP) in LT recipients, as well as to describe the prevalence of sarcopenia and malnutrition before and after RP and their influence on clinically relevant outcomes.

MATERIALS AND METHODS

Quasi-experimental study, before and after a 10-week PR in first-time TP recipients, aged over 18 years, from January 2022 to September 2023. Aerobic exercise capacity was assessed through the 6-minute walking test (6MWT) and peak oxygen consumption (VO2peak); and physical performance was measured using the Short Physical Performance Battery (SPPB). Additionally, the prevalence of sarcopenia was described according to the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2) and malnutrition according to the criteria of the Global Leadership Initiative on Malnutrition (GLIM).

RESULTS

Of the 41 patients, 56% had sarcopenia and 80% had malnutrition. After RP, the distance walked in the 6MWT increased by 66.3m (p=0.004) in men and 61m (p=0.001) in women. VO2peak increased in men by a mean of 3.1ml/min/kg (p=0.024). Physical performance improved significantly in both men and women according to the Short Physical Performance Battery (SPPB), with clinically relevant differences of 1.6 pts (p<0.001) and 1.2 pts (p=0.012), respectively. The prevalence of sarcopenia decreased to 24% and malnutrition to 61%.

CONCLUSIONS

RP proved to be an effective and safe intervention for LT recipients. In addition to improvements in skeletal muscle strength and exercise capacity, a reduction in the prevalence of sarcopenia and malnutrition was also observed.

The gut microbiome in end-stage lung disease and lung transplantation

Gut dysbiosis has been associated with impaired outcomes in liver and kidney transplant recipients, but the gut microbiome of lung transplant recipients has not been extensively explored. We assessed the gut microbiome in 64 fecal samples from end-stage lung disease patients before transplantation and 219 samples from lung transplant recipients after transplantation using metagenomic sequencing. To identify dysbiotic microbial signatures, we analyzed 243 fecal samples from age-, sex-, and BMI-matched healthy controls. By unsupervised clustering, we identified five groups of lung transplant recipients using different combinations of immunosuppressants and antibiotics and analyzed them in relation to the gut microbiome. Finally, we investigated the gut microbiome of lung transplant recipients in different chronic lung allograft dysfunction (CLAD) stages and longitudinal gut microbiome changes after transplantation. We found 108 species (58.1%) in end-stage lung disease patients and 139 species (74.7%) in lung transplant recipients that were differentially abundant compared with healthy controls, with several species exhibiting sharp longitudinal increases from before to after transplantation. Different combinations of immunosuppressants and antibiotics were associated with specific gut microbial signatures. We found that the gut microbiome of lung transplant recipients in CLAD stage 0 was more similar to healthy controls compared to those in CLAD stage 1. Finally, the gut microbial diversity of lung transplant recipients remained lower than the average gut microbial diversity of healthy controls up to more than 20 years post-transplantation. Gut dysbiosis, already present before lung transplantation was exacerbated following lung transplantation.IMPORTANCEThis study provides extensive insights into the gut microbiome of end-stage lung disease patients and lung transplant recipients, which warrants further investigation before the gut microbiome can be used for microbiome-targeted interventions that could improve the outcome of lung transplantation.

Orthostatic Hypotension and Antihypertensive Treatment in Lung Transplant Recipients: A Cross-Sectional Study

OBJECTIVES

Lung transplant is the ultimate treatment of many end-stage lung diseases. Calcineurin inhibitors, crucial in immunosuppression for lung transplant recipients, are linked to secondary hypertension, necessitating antihypertensive treatment. In addition, lung transplant recipients frequently experience orthostatic hypotension, occasionally stemming from autonomic dysfunction, but also commonly attributed as a negative side effect of antihypertensive treatment. Our study aimed to evaluate the frequency of orthostatic blood pressure irregularities and investigate the involvement of antihypertensive treatment as a potential risk factor in the occurrence among lung transplant recipients.

MATERIALS AND METHODS

Fifty-six consecutive lung transplant recipients, both inpatient and outpatient, at the University Hospital Zurich (Switzerland) were monitored from 1999 to 2013. Transplant recipients underwent a Schellong test (an active standing test). Our evaluation encompassed their initial traits, such as the existence of supine hypertension. We computed the odds ratio for the comparison of the likelihood of experiencing orthostatic hypotension while using a minimum of 1 type of antihypertensive medication versus absence of antihypertensive drugs.

RESULTS

Of the lung transplant recipients, 25% showed a positive Schellong test. Within this group, 64% had supine hypertension, and 29% displayed symptoms of orthostatic hypotension. Among the patients, 71% were using at least 1 type of antihypertensive medication. The odds ratio for showing orthostatic hypotension while taking at least 1 type of antihypertensive drug versus the absence of antihypertensive medications was 1.64 (95% exact CI, 0.39-6.90) with P = .50. This finding remained consistent regardless of age, sex, inpatient or outpatient status, and the duration since transplant.

CONCLUSIONS

Orthostatic blood pressure dysregulation is prevalent among lung transplant recipients, frequently without noticeable symptoms. In our cohort, the use of antihypertensive medications did not elevate the risk of orthostatic hypotension.

Impact of lung transplantation on diastolic dysfunction in recipients with pretransplant pulmonary hypertension

OBJECTIVE

Pulmonary hypertension can cause left ventricular diastolic dysfunction through ventricular interdependence. Moreover, diastolic dysfunction has been linked to adverse outcomes after lung transplant. The impact of lung transplant on diastolic dysfunction in recipients with pretransplant pulmonary hypertension is not defined. In this cohort, we aimed to assess the prevalence of diastolic dysfunction, the change in diastolic dysfunction after lung transplant, and the impact of diastolic dysfunction on lung transplant outcomes.

METHODS

In a large, single-center database from January 2011 to September 2021, single or bilateral lung transplant recipients with pulmonary hypertension (mean pulmonary artery pressure > 20 mm Hg) were retrospectively identified. Those without a pre- or post-transplant echocardiogram within 1 year were excluded. Diastolic dysfunction was diagnosed and graded according to the American Society of Echocardiography 2016 guideline on assessment of diastolic dysfunction (present, absent, indeterminate). McNemar's test was used to examine association between diastolic dysfunction pre- and post-transplant. Kaplan-Meier and Cox regression analysis were used to assess associations between pre-lung transplant diastolic dysfunction and post-lung transplant 1-year outcomes, including mortality, major adverse cardiac events, and bronchiolitis obliterans syndrome grade 1 or higher-free survival.

RESULTS

Of 476 primary lung transplant recipients, 205 with pulmonary hypertension formed the study cohort (mean age, 56.6 ± 11.9 years, men 61.5%, mean pulmonary artery pressure 30.5 ± 9.8 mm Hg, left ventricular ejection fraction < 55% 9 [4.3%]). Pretransplant, diastolic dysfunction was present in 93 patients (45.4%) (grade I = 8, II = 84, III = 1), absent in 16 patients (7.8%), and indeterminate in 89 patients (43.4%), and 7 patients (3.4%) had missing data. Post-transplant, diastolic dysfunction was present in 7 patients (3.4%) (grade I = 2, II = 5, III = 0), absent in 164 patients (80.0%), and indeterminate in 15 patients (7.3%), and 19 patients (9.3%) had missing data. For those with diastolic dysfunction grades in both time periods (n = 180), there was a significant decrease in diastolic dysfunction post-transplant (148/169 patients with resolved diastolic dysfunction; McNemar's test P < .001). Pretransplant diastolic dysfunction was not associated with major adverse cardiac events (hazard ratio [HR], 1.08, 95% CI, 0.72-1.62; P = .71), bronchiolitis obliterans syndrome-free survival (HR, 0.67, 95% CI, 0.39-1.56; P = .15), or mortality (HR, 0.70, 95% CI, 0.33-1.46; P = .34) at 1 year.

CONCLUSIONS

Diastolic dysfunction is highly prevalent in lung transplant candidates with normal left ventricular systolic function and pulmonary hypertension, and resolves in most patients after lung transplant regardless of patient characteristics. Pre-lung transplant diastolic dysfunction was not associated with adverse lung or cardiac outcomes after lung transplant. Collectively, these findings suggest that the presence of diastolic dysfunction in lung transplant recipients with pulmonary hypertension has no prognostic significance, and as such diastolic dysfunction and the associated clinical syndrome of heart failure with preserved ejection fraction should not be considered a relative contraindication to lung transplant in such patients.

Ex vivo lung perfusion and the Organ Care System: a review

With the increasing prevalence of heart failure and end-stage lung disease, there is a sustained interest in expanding the donor pool to alleviate the thoracic organ shortage crisis. Efforts to extend the standard donor criteria and to include donation after circulatory death have been made to increase the availability of suitable organs. Studies have demonstrated that outcomes with extended-criteria donors are comparable to those with standard-criteria donors. Another promising approach to augment the donor pool is the improvement of organ preservation techniques. Both ex vivo lung perfusion (EVLP) for the lungs and the Organ Care System (OCS, TransMedics) for the heart have shown encouraging results in preserving organs and extending ischemia time through the application of normothermic regional perfusion. EVLP has been effective in improving marginal or borderline lungs by preserving and reconditioning them. The use of OCS is associated with excellent short-term outcomes for cardiac allografts and has improved utilization rates of hearts from extended-criteria donors. While both EVLP and OCS have successfully transitioned from research to clinical practice, the costs associated with commercially available systems and consumables must be considered. The ex vivo perfusion platform, which includes both EVLP and OCS, holds the potential for diverse and innovative therapies, thereby transforming the landscape of thoracic organ transplantation.

Long-term outcomes of lung transplantation with ex vivo lung perfusion technique

Ex vivo lung perfusion (EVLP) has demonstrated encouraging short- and medium-term outcomes with limited data available on its long-term outcomes. This study assesses (1) EVLP long-term outcomes and (2) EVLP era-based sub-analysis in addition to secondary outcomes of recipients with EVLP-treated donor lungs compared with recipients of conventionally preserved donor lungs in unmatched and propensity score-matched cohorts. Double lung transplants performed between 1st January 2012 and 31st December 2021 were included. A total of 57 recipients received EVLP-treated lungs compared to 202 unmatched and 57 matched recipients who were subjected to non-EVLP-treated lungs. The EVLP group had a significantly lower mean PaO2/FiO2 ratio and significantly higher mean BMI than the non-EVLP group in the unmatched and matched cohorts. The proportion of smoking history in the unmatched cohort was significantly higher in the EVLP group, while a similar smoking history was demonstrated in the matched cohorts. No difference was demonstrated in overall freedom from death and retransplantation between the groups in the unmatched and matched cohorts (unmatched: hazard ratio (HR) 1.28, 95% confidence interval (CI) 0.79-2.07, P = 0.32; matched: HR 1.06, 95% CI 0.59-1.89). P = 0.89). In the unmatched cohort, overall freedom from chronic allograft dysfunction (CLAD) was significantly different between the groups (HR 1.64, 95% CI 1.07-2.52, P = 0.02); however, the cumulative CLAD incidence was similar (HR 0.72, 95% CI 0.48-1.1, P = 0.13). In the matched cohort, the overall freedom from CLAD (HR 1.69, 95% CI 0.97-2.95, P = 0.06) and cumulative CLAD incidence (HR 0.91, 95% CI 0.37-2.215, P = 0.83) were similar between the groups. The EVLP era sub-analysis of the unmatched cohort in 2012-2014 had a significantly higher cumulative CLAD incidence in the EVLP group; however, this was not demonstrated in the matched cohort. All secondary outcomes were similar between the groups in the unmatched and matched cohorts. In conclusion, transplantation of marginal donor lungs after EVLP evaluation is non-detrimental compared to conventionally preserved donor lungs in terms of mortality, retransplantation, cumulative CLAD incidence, and secondary outcomes. Although the unmatched EVLP era of 2012-2014 had a significantly higher cumulative CLAD incidence, no such finding was demonstrated in the matched cohort of the same era.

Lung Resection for Non-Small Cell Lung Cancer following Bronchoscopic Lung Volume Reduction for Heterogenous Emphysema

Bronchoscopic lung volume reduction (BLVR) is a minimally invasive treatment for emphysema. Lung cancer may be associated with emphysema due to common risk factors. Thus, a growing number of patients undergoing BLVR may develop lung cancer. Herein, we evaluated the effects of lung resection for non-small cell lung cancer in patients undergoing BLVR. The clinical data of patients undergoing BLVR followed by lung resection for NSCLC were retrospectively reviewed. For each patient, surgical and oncological outcomes were recorded to define the effects of this strategy. Eight patients were included in our series. In all cases but one, emphysema was localized within upper lobes; the tumor was detected during routine follow-up following BLVR and it did not involve the treated lobe. The comparison of pre- and post-BLVR data showed a significant improvement in FEV1 (29.7 ± 4.9 vs. 33.7 ± 6.7, p = 0.01); in FVC (28.5 ± 6.6 vs. 32.4 ± 6.1, p = 0.01); in DLCO (31.5 ± 4.9 vs. 38.7 ± 5.7, p = 0.02); in 6MWT (237 ± 14 m vs. 271 ± 15 m, p = 0.01); and a reduction in RV (198 ± 11 vs. 143 ± 9.8, p = 0.01). Surgical resection of lung cancer included wedge resection (n = 6); lobectomy (n = 1); and segmentectomy (n = 1). No major complications were observed and the comparison of pre- and post-operative data showed no significant reduction in FEV1% (33.7 ± 6.7 vs. 31.5 ± 5.3; p = 0.15) and in DLCO (38.7 ± 5.7 vs. 36.1 ± 5.4; p = 0.15). Median survival was 35 months and no cancer relapses were observed. The improved lung function obtained with BLVR allowed nonsurgical candidates to undergo lung resection for lung cancer.

Lung Transplantation for Pulmonary Artery Hypertension

This manuscript discusses the role of lung transplantation in patients with pulmonary hypertension. The indications and timing for referral to a transplant unit and timing for wait-listing for lung transplantation are discussed. The type of transplantation—isolated (single or double) lung transplantation and situations when combined heart and double lung transplantation is indicated—will be elaborated. Escalation of medical therapy with the need and timing for bridging therapies such as extracorporeal membrane oxygenation until an appropriate organ becomes available will be discussed. Challenges in the postoperative period, specific to lung transplantation for pulmonary artery hypertension, will be reviewed. The outcomes following lung transplantation will also be considered in greater detail.

Immunomodulation of the donor lung with CRISPR-mediated activation of IL-10 expression

BACKGROUND

Inflammatory injury in the donor lung remains a persistent challenge in lung transplantation that limits donor organ usage and post-transplant outcomes. Inducing immunomodulatory capacity in donor organs could address this unsolved clinical problem. We sought to apply clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) technologies to the donor lung to fine-tune immunomodulatory gene expression, exploring for the first time the therapeutic use of CRISPR-mediated transcriptional activation in the whole donor lung.

METHODS

We explored the feasibility of CRISPR-mediated transcriptional upregulation of interleukin 10 (IL-10), a key immunomodulatory cytokine, in vitro and in vivo. We first evaluated the potency, titratability, and multiplexibility of the gene activation in rat and human cell lines. Next, in vivo CRISPR-mediated IL-10 activation was characterized in rat lungs. Finally, the IL-10-activated donor lungs were transplanted into recipient rats to assess the feasibility in a transplant setting.

RESULTS

The targeted transcriptional activation induced robust and titrable IL-10 upregulation in vitro. The combination of guide RNAs also facilitated multiplex gene modulation, that is, simultaneous activation of IL-10 and IL1 receptor antagonist. In vivo profiling demonstrated that adenoviral delivery of Cas9-based activators to the lung was feasible with the use of immunosuppression, which is routinely applied to organ transplant recipients. The transcriptionally modulated donor lungs retained IL-10 upregulation in isogeneic and allogeneic recipients.

CONCLUSIONS

Our findings highlight the potential of CRISPR epigenome editing to improve lung transplant outcomes by creating a more favorable immunomodulatory environment in the donor organ, a paradigm that may be extendable to other organ transplants.

Collagen Type IV Alpha 5 Chain in Bronchiolitis Obliterans Syndrome After Lung Transplant: The First Evidence

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS) is the most common form of CLAD and is characterized by airflow limitation and an obstructive spirometry pattern without parenchymal opacities. The protein signature of BOS lesions concerns extracellular matrix organization and aberrant basement membrane composition. In this pilot study, we investigated the presence of COL4A5 in the serum of patients with BOS.

METHODS

41 patients who had undergone LTX were enrolled. Of these, 27 developed BOS and 14 (control group) were considered stable at the time of serum sampling. Of BOS patients, serum samples were analysed at the time of BOS diagnosis and before the clinical diagnosis (pre-BOS). COL4A5 levels were detected through the ELISA kit.

RESULTS

Serum concentrations of COL4A5 were higher in pre-BOS than in stable patients (40.5 ± 13.9 and 24.8 ± 11.4, respectively, p = 0.048). This protein is not influenced by comorbidities, such as acute rejection or infections, or by therapies. Survival analysis also reveals that a higher level of COL4A5 was also associated with less probability of survival. Our data showed a correlation between concentrations of COL4A5 and FEV1 at the time of diagnosis of BOS.

CONCLUSION

Serum concentrations of COL4A5 can be considered a good prognostic marker due to their association with survival and correlation with functional parameters.

Homelessness, organ donation, transplantation, and a call for equity in the United States

While social justice is a pillar that society seeks to uphold, in the area of organ transplantation, social justice, equity, and inclusion fail in the unbefriended and undomiciled population. Due to lack of social support of the homeless population, such status often renders these individuals ineligible to be organ recipients. Though it can be argued that organ donation by an unbefriended, undomciled patient benefits the greater good, there is clear inequity in the fact that homeless individuals are denied transplants due to inadequate social support. To illustrate such social breakdown, we describe two unbefriended, undomiciled patients brought to our hospitals by emergency services with diagnoses of intracerebral haemorrhage that progressed to brain death. This proposal represents a call to action to remediate the broken system: how the inherent inequity in organ donation by unbefriended, undomiciled patients would be ethically optimized if social support systems were implemented to allow for their candidacy for organ transplantation.

Biased IL-2 signals induce Foxp3-rich pulmonary lymphoid structures and facilitate long-term lung allograft acceptance in mice

Transplantation of solid organs can be life-saving in patients with end-stage organ failure, however, graft rejection remains a major challenge. In this study, by pre-conditioning with interleukin-2 (IL-2)/anti-IL-2 antibody complex treatment biased toward IL-2 receptor α, we achieved acceptance of fully mismatched orthotopic lung allografts that remained morphologically and functionally intact for more than 90 days in immunocompetent mice. These allografts are tolerated by the actions of forkhead box p3 (Foxp3)⁺ regulatory T (Treg) cells that home to the lung allografts. Although counts of circulating Treg cells rapidly return to baseline following cessation of IL-2 treatment, Foxp3⁺ Treg cells persist in peribronchial and peribronchiolar areas of the grafted lungs, forming organized clusters reminiscent of inducible tertiary lymphoid structures (iTLS). These iTLS in lung allografts are made of Foxp3⁺ Treg cells, conventional T cells, and B cells, as evidenced by using microscopy-based distribution and neighborhood analyses. Foxp3-transgenic mice with inducible and selective deletion of Foxp3⁺ cells are unable to form iTLS in lung allografts, and these mice acutely reject lung allografts. Collectively, we report that short-term, high-intensity and biased IL-2 pre-conditioning facilitates acceptance of vascularized and ventilated lung allografts without the need of immunosuppression, by inducing Foxp3-controlled iTLS formation within allografts.

Development of nintedanib nanosuspension for inhaled treatment of experimental silicosis

Silicosis is an irreversible and progressive fibrotic lung disease caused by massive inhalation of crystalline silica dust at workplaces, affecting millions of industrial workers worldwide. A tyrosine kinase inhibitor, nintedanib (NTB), has emerged as a potential silicosis treatment due to its inhibitory effects on key signaling pathways that promote silica-induced pulmonary fibrosis. However, chronic and frequent use of the oral NTB formulation clinically approved for treating other fibrotic lung diseases often results in significant side effects. To this end, we engineered a nanocrystal-based suspension formulation of NTB (NTB-NS) possessing specific physicochemical properties to enhance drug retention in the lung for localized treatment of silicosis via inhalation. Our NTB-NS formulation was prepared using a wet-milling procedure in presence of Pluronic F127 to endow the formulation with nonadhesive surface coatings to minimize interactions with therapy-inactivating delivery barriers in the lung. We found that NTB-NS, following intratracheal administration, provided robust anti-fibrotic effects and mechanical lung function recovery in a mouse model of silicosis, whereas a 100-fold greater oral NTB dose given with a triple dosing frequency failed to do so. Importantly, several key pathological phenotypes were fully normalized by NTB-NS without displaying notable local or systemic adverse effects. Overall, NTB-NS may open a new avenue for localized treatment of silicosis and potentially other fibrotic lung diseases.

Determining the impact of ex-vivo lung perfusion on hospital costs for lung transplantation: A retrospective cohort study

INTRODUCTION

Ex-vivo lung perfusion (EVLP) has improved organ utilization for lung transplantation, but it is not yet known whether the benefits of this technology offset its additional costs. We compared the institutional costs of lung transplantation before vs after EVLP was available to identify predictors of costs and determine the health-economic impact of EVLP.

METHODS

We performed a retrospective, before-after, propensity-score weighted cohort study of patients wait-listed for lung transplant at University Health Network (UHN) in Ontario, Canada, between January 2005 and December 2019 using institutional administrative data. We compared costs, in 2019 Canadian Dollars ($), between patients referred for transplant before EVLP was available (Pre-EVLP) to after (Modern EVLP). Cumulative costs were estimated using a novel application of multistate survival models. Predictors of costs were identified using weighted log-gamma generalized linear regression.

RESULTS

A total of 1,199 patients met inclusion criteria (352 Pre-EVLP; 847 Modern EVLP). Mean total costs for the transplant hospitalization were $111,878 ($94,123-$130,767) in the Pre-EVLP era and $110,969 ($87,714-$136,000) in the Modern EVLP era. Cumulative five-year costs since referral were $278,777 ($82,575-$298,135) in the Pre-EVLP era and $293,680 ($252,832-$317,599) in the Modern EVLP era. We observed faster progression to transplantation when EVLP was available. EVLP availability was not a predictor of waitlist (cost ratio [CR] 1.04 [0.81-1.37]; p = 0.354) or transplant costs (CR 1.02 [0.80-1.29]; p = 0.425) but was associated with lower costs during posttransplant years 1&2 (CR 0.75 [0.58-1.06]; p = 0.05) and posttransplant years 3+ (CR 0.43 [0.26-0.74]; p = 0.001).

CONCLUSIONS

At our center, EVLP availability was associated with faster progression to transplantation at no significant marginal cost.

Testing the delivery of human organ transportation with drones in the real world

Last-mile transportation of human donor lungs in a densely populated urban environment has been made possible with drones.

Roles of electrical impedance tomography in lung transplantation

Lung transplantation is the preferred treatment method for patients with end-stage pulmonary disease. However, several factors hinder the progress of lung transplantation, including donor shortages, candidate selection, and various postoperative complications. Electrical impedance tomography (EIT) is a functional imaging tool that can be used to evaluate pulmonary ventilation and perfusion at the bedside. Among patients after lung transplantation, monitoring the graft’s pulmonary function is one of the most concerning issues. The feasible application of EIT in lung transplantation has been reported over the past few years, and this technique has gained increasing interest from multidisciplinary researchers. Nevertheless, physicians still lack knowledge concerning the potential applications of EIT in lung transplantation. We present an updated review of EIT in lung transplantation donors and recipients over the past few years, and discuss the potential use of ventilation- and perfusion-monitoring-based EIT in lung transplantation.

Correlation between Neutrophil Extracellular Traps (NETs) Expression and Primary Graft Dysfunction Following Human Lung Transplantation

Primary graft dysfunction (PGD) is characterized by alveolar epithelial and vascular endothelial damage and inflammation, lung edema and hypoxemia. Up to one-third of recipients develop the most severe form of PGD (Grade 3; PGD3). Animal studies suggest that neutrophils contribute to the inflammatory process through neutrophil extracellular traps (NETs) release (NETosis). NETs are composed of DNA filaments decorated with granular proteins contributing to vascular occlusion associated with PGD. The main objective was to correlate NETosis in PGD3 (n = 9) versus non-PGD3 (n = 27) recipients in an exploratory study. Clinical data and blood samples were collected from donors and recipients pre-, intra- and postoperatively (up to 72 h). Inflammatory inducers of NETs' release (IL-8, IL-6 and C-reactive protein [CRP]) and components (myeloperoxidase [MPO], MPO-DNA complexes and cell-free DNA [cfDNA]) were quantified by ELISA. When available, histology, immunohistochemistry and immunofluorescence techniques were performed on lung biopsies from donor grafts collected during the surgery to evaluate the presence of activated neutrophils and NETs. Lung biopsies from donor grafts collected during transplantation presented various degrees of vascular occlusion including neutrophils undergoing NETosis. Additionally, in recipients intra- and postoperatively, circulating inflammatory (IL-6, IL-8) and NETosis biomarkers (MPO-DNA, MPO, cfDNA) were up to 4-fold higher in PGD3 recipients compared to non-PGD3 (p = 0.041 to 0.001). In summary, perioperative elevation of NETosis biomarkers is associated with PGD3 following human lung transplantation and these biomarkers might serve to identify recipients at risk of PGD3 and initiate preventive therapies.

Health-Related Quality of Life Outcomes Following Single or Bilateral Lung Transplantation: A Systematic Review

BACKGROUND

Lung transplantation is the definitive treatment for end-stage lung disease. There has been uncertainty regarding whether single or bilateral lung transplantation confers patients' greater health-related quality of life. This systematic review was performed to evaluate the impact of single lung transplantation (SLTx) against bilateral lung transplantation on short- and long-term health-related quality of life.

METHODS

A literature search was conducted on PubMed for studies matching the eligibility criteria between January 2000 and January 2022. OVID (MEDLINE), Google Scholar, EBSCOhost (EMBASE), and bibliographies of included studies were reviewed. Inclusion of studies was based on predetermined eligibility criteria. Quality appraisal and data tabulation were performed using predetermined forms. Results were synthesized by narrative review. The structure of this systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This systematic review was prospectively registered in the PROSPERO register (CRD42022344389).

RESULTS

Ten studies (1916 patients) were included. Within 12 mo posttransplantation, there was no evidence of the improved health-related quality of life with respect to the type of lung transplantation procedure. Bilateral lung transplantation patients reported significantly greater scores in both the physical and mental health domains of health-related quality of life. Bilateral lung transplantation offered significantly better health-related quality of life outcomes at later follow-up periods. Bilateral lung transplantation showed a significantly slower reduction in health-related quality of life physical composite scores relative to SLTx.

CONCLUSION

Bilateral lung transplant (BLTx) recipients perceive the greater health-related quality of life beyond 1-y post-lung transplantation. BLTx recipients better retain their health-related quality of life long-term posttransplantation than those receiving SLTx.

Outcomes of Patients on the Lung Transplantation Waitlist in Korea: A Korean Network for Organ Sharing Data Analysis

BACKGROUND

The demand for lung transplants continues to increase in Korea, and donor shortages and waitlist mortality are critical issues. This study aimed to evaluate the factors that affect waitlist outcomes from the time of registration for lung transplantation in Korea.

METHODS

Data were obtained from the Korean Network for Organ Sharing for lung-only registrations between September 7, 2009, and December 31, 2020. Post-registration outcomes were evaluated according to the lung disease category, blood group, and age.

RESULTS

Among the 1,671 registered patients, 49.1% had idiopathic pulmonary fibrosis (group C), 37.0% had acute respiratory distress syndrome and other interstitial lung diseases (group D), 7.2% had chronic obstructive pulmonary disease (group A), and 6.6% had primary pulmonary hypertension (group B). Approximately half of the patients (46.1%) were transplanted within 1 year of registration, while 31.8% died without receiving a lung transplant within 1 year of registration. Data from 1,611 patients were used to analyze 1-year post-registration outcomes, which were classified as transplanted (46.1%, n = 743), still awaiting (21.1%, n = 340), removed (0.9%, n = 15), and death on waitlist (31.8%, n = 513). No significant difference was found in the transplantation rate according to the year of registration. However, significant differences occurred between the waitlist mortality rates (P = 0.008) and the still awaiting rates (P = 0.009). The chance of transplantation after listing varies depending on the disease category, blood type, age, and urgency status. Waitlist mortality within 1 year was significantly associated with non-group A disease (hazard ratio [HR], 2.76, P < 0.001), age ≥ 65 years (HR, 1.48, P < 0.001), and status 0 at registration (HR, 2.10, P < 0.001).

CONCLUSION

Waitlist mortality is still higher in Korea than in other countries. Future revisions to the lung allocation system should take into consideration the high waitlist mortality and donor shortages.

Ischemia reperfusion injury facilitates lung allograft acceptance through IL-33-mediated activation of donor-derived IL-5 producing group 2 innate lymphoid cells

Pathways regulating lung alloimmune responses differ from most other solid organs and remain poorly explored. Based on our recent work identifying the unique role of eosinophils in downregulating lung alloimmunity, we sought to define pathways contributing to eosinophil migration and homeostasis. Using a murine lung transplant model, we have uncovered that immunosuppression increases eosinophil infiltration into the allograft in an IL-5-dependent manner. IL-5 production depends on immunosuppression-mediated preservation of donor-derived group 2 innate lymphoid cells (ILC2). We further describe that ischemia reperfusion injury upregulates the expression of IL-33, which functions as the dominant and nonredundant mediator of IL-5 production by graft-resident ILC2. Our work thus identifies unique cellular mechanisms that contribute to lung allograft acceptance. Notably, ischemia reperfusion injury, widely considered to be solely deleterious to allograft survival, can also downregulate alloimmune responses by initiating unique pathways that promote IL-33/IL-5/eosinophil-mediated tolerance.

Reduction of primary graft dysfunction using cytokine adsorption during organ preservation and after lung transplantation

Despite improvements, lung transplantation remains hampered by both a scarcity of donor organs and by mortality following primary graft dysfunction (PGD). Since acute respiratory distress syndrome (ARDS) limits donor lungs utilization, we investigated cytokine adsorption as a means of treating ARDS donor lungs. We induced mild to moderate ARDS using lipopolysaccharide in 16 donor pigs. Lungs were then treated with or without cytokine adsorption during ex vivo lung perfusion (EVLP) and/or post-transplantation using extracorporeal hemoperfusion. The treatment significantly decreased cytokine levels during EVLP and decreased levels of immune cells post-transplantation. Histology demonstrated fewer signs of lung injury across both treatment periods and the incidence of PGD was significantly reduced among treated animals. Overall, cytokine adsorption was able to restore lung function and reduce PGD in lung transplantation. We suggest this treatment will increase the availability of donor lungs and increase the tolerability of donor lungs in the recipient.

Lung transplantation is hindered by the scarcity of organs and by mortality following primary graft dysfunction. Here, the authors show that cytokine absorption can be used in donor lungs during ex vivo lung perfusion and post-transplant, and leads to restored lung function and reduced primary graft dysfunction in animal models.

Emerging Paradigms in Bioengineering the Lungs

In end-stage lung diseases, the shortage of donor lungs for transplantation and long waiting lists are the main culprits in the significantly increasing number of patient deaths. New strategies to curb this issue are being developed with the help of recent advancements in bioengineering technology, with the generation of lung scaffolds as a steppingstone. There are various types of lung scaffolds, namely, acellular scaffolds that are developed via decellularization and recellularization techniques, artificial scaffolds that are synthesized using synthetic, biodegradable, and low immunogenic materials, and hybrid scaffolds which combine the advantageous properties of materials in the development of a desirable lung scaffold. There have also been advances in the design of bioreactors in terms of providing an optimal regenerative environment for the maturation of functional lung tissue over time. In this review, the emerging paradigms in the field of lung tissue bioengineering will be discussed.

Nursing experience of abdominal massage intervention for gastrointestinal dysfunction after lung transplantation

BACKGROUND

Lung transplantation is the only effective way to treat end-stage lung disease. Severe gastrointestinal complications are common after lung transplantation and are associated with increased mortality. Early identification and active intervention are necessary to avoid treatment delays. Abdominal massage belongs to the category of external treatment of traditional Chinese medicine (TCM), which is often used in the treatment of internal diseases. It has an excellent effect in treating stomachache, bloating, anorexia, and constipation.

CASE PRESENTATION

The patient developed gastrointestinal dysfunction 16 days after lung transplantation. Through the implementation of abdominal massage intervention, symptoms were significantly relieved, weight gain occurred, and the curative effect was good.

CONCLUSION

Abdominal massage can relieve gastrointestinal symptoms and promote the recovery of gastrointestinal function after lung transplantation and has good curative effects. This method is worth promoting in patients who have had lung transplantation.

Awakening in extracorporeal membrane oxygenation as a bridge to lung transplantation

Although the rate of lung transplantation (LTx), the last treatment option for end-stage lung disease, is increasing, some patients waiting for LTx need a bridging strategy for LTx due to the limited number of available donor lungs. For a long time, mechanical ventilation has been employed as a bridge to LTx because the outcome of using extracorporeal membrane oxygenation (ECMO) as a bridging strategy has been poor. However, the outcome after mechanical ventilation as a bridge to LTx was poor compared with that in patients without bridges. With advances in technology and the accumulation of experience, the outcome of ECMO as a bridge to LTx has improved, and the rate of ECMO use as a bridging strategy has increased over time. However, whether the use of ECMO as a bridge to LTx can achieve survival rates similar to those of non-bridged LTx patients remains controversial. In 2010, one center introduced awake ECMO strategy for LTx bridging, and its use as a bridge to LTx has been showing favorable outcomes to date. Awake ECMO has several advantages, such as maintenance of physical activity, spontaneous breathing, avoidance of endotracheal intubation, and reduced use of sedatives and analgesics, but it may cause serious problems. Nonetheless, several studies have shown that awake ECMO performed by a multidisciplinary team is safe. In cases where ECMO or mechanical ventilation is required due to unavoidable exacerbation in patients awaiting LTx, the application of awake ECMO performed by an appropriately trained ECMO multi-disciplinary team can be useful.

Multi-omics profiling predicts allograft function after lung transplantation

RATIONALE

Lung transplantation is the ultimate treatment option for patients with end-stage respiratory diseases but bears the highest mortality rate among all solid organ transplantations due to chronic lung allograft dysfunction (CLAD). The mechanisms leading to CLAD remain elusive due to an insufficient understanding of the complex post-transplant adaptation processes.

OBJECTIVES

To better understand these lung adaptation processes after transplantation and to investigate their association with future changes in allograft function.

METHODS

We performed an exploratory cohort study of bronchoalveolar lavage samples from 78 lung recipients and donors. We analysed the alveolar microbiome using 16S rRNA sequencing, the cellular composition using flow cytometry, as well as metabolome and lipidome profiling.

MEASUREMENTS AND MAIN RESULTS

We established distinct temporal dynamics for each of the analysed data sets. Comparing matched donor and recipient samples, we revealed that recipient-specific as well as environmental factors, rather than the donor microbiome, shape the long-term lung microbiome. We further discovered that the abundance of certain bacterial strains correlated with underlying lung diseases even after transplantation. A decline in forced expiratory volume during the first second (FEV1) is a major characteristic of lung allograft dysfunction in transplant recipients. By using a machine learning approach, we could accurately predict future changes in FEV1 from our multi-omics data, whereby microbial profiles showed a particularly high predictive power.

CONCLUSION

Bronchoalveolar microbiome, cellular composition, metabolome and lipidome show specific temporal dynamics after lung transplantation. The lung microbiome can predict future changes in lung function with high precision.

Economic evaluations and costing studies of lung transplantation: A scoping review

BACKGROUND

Evaluation of the joint clinical and economic impacts of lung transplant and associated technologies is crucial for evidence-informed decision-making and wise allocation of scarce healthcare resources. We performed a scoping review to summarize and categorize the available evidence of the costs and cost-effectiveness of lung transplantation.

METHODS

A systematic search of MEDLINE, EMBASE, NHS EED, and EconLit was performed to identify studies involving lung transplantation for adults that measured costs, cost-effectiveness, or which described themselves as economic evaluations. A scoping review was performed in adherence to the framework described by Arksey & O'Malley. Risk of bias was assessed in included studies using the ECOBIAS and CHEC-list tools.

RESULTS

In total, 324 studies were identified, of which 28 met inclusion criteria. Cost-utility estimates of lung transplant versus waitlist, from the healthcare payer perspective and a time-horizon of at least 10-years ranged between $42,459 and $154,051 per quality-adjusted life year. Common topics of study included lung transplant versus waitlist care, immunosuppression, organ retrieval and allocation, and mechanical life support.

CONCLUSIONS

Sources of variation in costs-assessments and economic evaluations included differences in the type of study performed, payer perspective adopted, study time horizon, and variation in clinical practice. The best available cost-utility estimates for lung transplant versus waitlist may represent cost-effectiveness under some circumstances, but high-quality evidence is lacking. Further cost-utility analyses, with sufficient methodologic rigour, are required to overcome the observed variation in results and confirm cost-effectiveness of the current standard of care in lung transplantation.

Blocking hyaluronan synthesis alleviates acute lung allograft rejection

Lung allograft rejection results in the accumulation of low–molecular weight hyaluronic acid (LMW-HA), which further propagates inflammation and tissue injury. We have previously shown that therapeutic lymphangiogenesis in a murine model of lung allograft rejection reduced tissue LMW-HA and was associated with improved transplant outcomes. Herein, we investigated the use of 4-Methylumbelliferone (4MU), a known inhibitor of HA synthesis, to alleviate acute allograft rejection in a murine model of lung transplantation. We found that treating mice with 4MU from days 20 to 30 after transplant was sufficient to significantly improve outcomes, characterized by a reduction in T cell–mediated lung inflammation and LMW-HA content and in improved pathology scores. In vitro, 4MU directly attenuated activation, proliferation, and differentiation of naive CD4⁺ T cells into Th1 cells. As 4MU has already been demonstrated to be safe for human use, we believe examining 4MU for the treatment of acute lung allograft rejection may be of clinical significance.

Looking Beyond the Allograft Survival: Long-Term, 5-Year Renal Outcome in Lung Transplant Recipients

With the increased incidence and survival of lung transplant (LTx) recipients, the risk for chronic sequelae such as chronic kidney disease (CKD) is on the rise. Data on the long-term renal outcome are scarce. We performed a retrospective chart review of 171 adults with LTx from January 1, 2014, to January 1, 2019. Primary outcomes were prevalence of CKD/end-stage renal disease, acute kidney injury (AKI) as a risk factor for future CKD, and all-cause mortality in recipients with CKD compared with the non-CKD group. Secondary outcomes were frequency of utilization of modalities for CKD (urinalysis, imaging, biopsy, nephrology consultations). Baseline median creatinine and estimated glomerular filtration rate (eGFR) were 0.8 mg/dL and 90 mL/min/1.73 m², respectively. Of the participants, 60% (96 of 161), 67% (102 of 153), 79% (37 of 47), 86% (10 of 12) had CKD at the end of 6, 12, 36, and 60 months, respectively, and 16% were on dialysis at the end of the study period; 3% received a subsequent renal transplant, and 27% mortality was noted over a 5-year follow-up period. The odds of CKD development in patients with an AKI during index hospitalization vs no AKI was 6.22 (2.87 to 13.06, P < .0001). The odds ratio of all-cause mortality in patients with CKD compared with non-CKD was 3.36 (95% confidence interval, 1.44-8.64, P = .005). Measurement of hematuria/proteinuria, imaging, and renal biopsy were infrequently used. Given the high prevalence of AKI and CKD in this population, a multidisciplinary team approach with an early nephrology consultation will be key to improve the overall and renal outcomes in LTx recipients.

Decellularized human-sized pulmonary scaffolds for lung tissue engineering: a comprehensive review

The ultimate goal of lung bioengineering is to produce transplantable lungs for human beings. Therefore, large-scale studies are of high importance. In this paper, we review the investigations on decellularization and recellularization of human-sized lung scaffolds. First, studies that introduce new ways to enhance the decellularization of large-scale lungs are reviewed, followed by the investigations on the xenogeneic sources of lung scaffolds. Then, decellularization and recellularization of diseased lung scaffolds are discussed to assess their usefulness for tissue engineering applications. Next, the use of stem cells in recellularizing acellular lung scaffolds is reviewed, followed by the case studies on the transplantation of bioengineered lungs. Finally, the remaining challenges are discussed, and future directions are highlighted.

Osteopontin and Transplantation: Where Are We Now?

Organ transplantation represents the optimal therapeutic tool for patients with end-stage organ failure. Hematopoietic stem cell transplantation (HSCT) is likewise an effective therapy for a wide range of malignant and non-malignant diseases. Better understanding of transplantation immunology and the use of multi-modal immunosuppression protocols, can decrease the risk of graft failure and graft-versus-host disease (GVHD) after HSCT. Nevertheless, a major challenge of modern transplantology still seems to be finding non-invasive biomarkers for recipients selection, monitoring of allograft function, and diagnosis of rejection. Since proinflammatory cytokine osteopontin (OPN) is closely involved in regulating both adaptive and innate immune responses, as well as the pathogenesis of inflammatory and autoimmune diseases, it is likely to play an important role in organ and HSC transplantation. This review is to summarize recent advances in our knowledge about OPN function in the kidney, heart, liver, lung, and HSC transplantation. Most studies found that elevated OPN is associated with poorer graft function in kidney, heart, liver and lung recipients. Moreover, some reports suggested that this protein can play role in GVHD pathogenesis. However, due to relatively small number of similar studies, as well as some inconclusive results, future investigation in this field is needed to verify if OPN can serve as a biomarker of organ and HSC transplantation. The knowledge about such markers will promote our understanding of the mechanisms underlying graft dysfunction and posttransplant mortality. In addition, such knowledge may be helpful in the development of new treatment strategies and identification of recipients with increased risk of allograft failure.

Evolution of Recipient Characteristics Over 3 Decades and Impact on Survival After Lung Transplantation

BACKGROUND

Lung transplantation (LTx) is a definitive treatment for end-stage lung disease. Herein, we reviewed our center experience over three decades to examine the evolution of recipient characteristics and contemporary predictors of survival for LTx.

METHODS

We retrospectively reviewed the data of LTx procedures performed at our institution from 1/1990 to 1/2019 (n=1819). The cohort is divided into three eras; I: 1990-1998 (n=152), II: 1999-2008 (n=521), III: 2009-2018 (n=1146). Uni- and multivariate analyses of survival in era III were performed.

RESULTS

Pulmonary fibrosis has become the leading indication for LTx (13% in Era I, 57% in Era III). Median recipient age increased (Era I: 46 years - Era III: 61 years) as well as intraoperative mechanical circulatory support (Era I: 0% - Era III: 6%). Higher lung allocation score (LAS) was associated with primary graft dysfunction (PGD) (p<0.0001), postoperative ECMO (p<0.0001), and in-hospital mortality (p=0.002). In Era III, hypoalbuminemia, thrombocytopenia, and high PGD grade were multivariate predictors of early mortality. The 5-year survival in Era II (55%) and III (55%) were superior to Era I (40%, p<0.001). Risk factors for late mortality in era III included recipient age, chronic allograft dysfunction, renal dysfunction, high MELD score, and single LTx.

CONCLUSIONS

In this longitudinal single-center study, recipient characteristics have evolved to include sicker patients with greater complexity of procedures and risk for postoperative complications but without significant impact on hospital mortality or long-term survival. With advancing surgical techniques and perioperative management, there is room for further progress in the field.Supplemental Visual Abstract; http://links.lww.com/TP/C191.

Kidney failure after lung transplantation in systemic scleroderma: a case report with literature review

Background

Systemic scleroderma (SSc) involves multiple organs including the skin, the lung, the kidney, and the esophagus. Nowadays, patient life prognosis has substantially improved due to more appropriate management of lung complications, including lung transplantation. However, the extension of their survival may increase SSc patients with chronic kidney diseases and requiring renal replacement therapy (RRT).

Case presentation

A 51-year-old female with SSc who underwent unilateral deceased-donor lung transplantation was referred because of progressive renal dysfunction. Despite no episodes of scleroderma renal crisis, her renal function gradually deteriorated for 2 years with her serum creatinine level increasing from 0.5 mg/dL at transplantation to 4.3 mg/dL. Although we reinforced antihypertensive treatment and reduced calcineurin inhibitor dose, she thereafter developed symptomatic uremia. Due to impaired manual dexterity with contracture of the interphalangeal joints, no caregivers at home, and kidney transplantation donor unavailability, maintenance hemodialysis was chosen as RRT modality. Further, due to the narrowing of superficial vessels in the sclerotic forearm skin and post-transplant immunocompromised status, the native left brachiocephalic arteriovenous fistula was created. Post-operative course was uneventful while any sign of cutaneous infection and pulmonary hypertension was closely monitored. Our literature review also indicates several difficulties with initiating and maintaining RRT in patients with SSc although case reports of kidney failure after lung transplanation in SSc were not accumulated.

Conclusions

With respect to initiating RRT for post-lung transplant patients with SSc, the clinical course of our case exemplifies recent complex trends of renal management. The optimal modality with secured initiation of RRT should be carefully determined based on the severity and risk for the cardiopulmonary, peripheral vascular, cutaneous, and systemic or local infectious complications.

Mitochondria as Therapeutic Targets in Transplantation

Advances in surgical procedures, technology, and immune suppression have transformed organ transplantation. However, the metabolic changes that occur during organ retrieval, storage, and implantation have been relatively neglected since the developments many decades ago of cold storage organ preservation solutions. In this review we discuss how the metabolic changes that occur within the organ during transplantation, particularly those associated with mitochondria, may contribute to the outcome. We show how a better understanding of these processes can lead to changes in surgical practice and the development of new drug classes to improve the function and longevity of transplanted grafts, while increasing the pool of organs available for transplantation.

Review 1: Lung transplant-from donor selection to graft preparation

For various end-stage lung diseases, lung transplantation remains one of the only viable treatment options. While the demand for lung transplantation has steadily risen over the last few decades, the availability of donor grafts is limited, which have resulted in progressively longer waiting lists. In the early years of lung transplantation, only the 'ideal' donor grafts are considered for transplantation. Due to the donor shortages, there is ongoing discussion about the safe use of 'suboptimal' grafts to expand the donor pool. In this review, we will discuss the considerations around donor selection, donor-recipient matching, graft preparation and graft optimisation.

Review 2: Primary graft dysfunction after lung transplant-pathophysiology, clinical considerations and therapeutic targets

Primary graft dysfunction (PGD) is one of the most common complications in the early postoperative period and is the most common cause of death in the first postoperative month. The underlying pathophysiology is thought to be the ischaemia–reperfusion injury that occurs during the storage and reperfusion of the lung engraftment; this triggers a cascade of pathological changes, which result in pulmonary vascular dysfunction and loss of the normal alveolar architecture. There are a number of surgical and anaesthetic factors which may be related to the development of PGD. To date, although treatment options for PGD are limited, there are several promising experimental therapeutic targets. In this review, we will discuss the pathophysiology, clinical management and potential therapeutic targets of PGD.

First Lung Transplantation in Jehovah's Witness Patient in Latin America

Lung transplantation is a life-saving alternative for patients with end-stage lung disease. The procedure itself has a high risk of bleeding. Jehovah’s Witness patients refuse to accept blood products due to religious beliefs. A 48-year-old Jehovah’s Witness woman presented with an 8-year history of cough, dyspnea along with progressive worsening of her functional class and quality of life. A diagnosis of autoimmune interstitial lung disease was made, for which cyclophosphamide was administered without improvement of symptoms, and the patient was accepted as a transplant candidate. Transplantation was performed without complications, nor blood products requirement, intraoperative cell salvage was performed, and pharmacological agents were used preoperatively for bleeding prevention. The patient only developed anemia after administration of immunosuppressor therapy, which was treated with erythropoietin in the outpatient setting.

National Trends in Extended Criteria Donor Utilization and Outcomes for Lung Transplantation

BACKGROUND

Extended criteria donor (ECD) for lung transplantation (LTx) have been implemented due to the donor organ shortage. The impact on recipient survival is under investigation. We report trends in the use of extended criteria lungs in the modern era and its association with survival outcomes using a large national database.

METHODS

We performed a retrospective analysis of all adult LTx from May 2005 to December 2018 using the United Network for Organ Sharing database. ECD were defined by 2 or more variances from standard criteria: age ≥ 55 years, pO2 ≤ 300, pack years ≥ 20, diabetes, purulent bronchoscopy, blood infection, or abnormal chest radiographs. Transplant centers were dichotomized based on volume. Recipient survival was analyzed using lung allocation score as a covariate.

RESULTS

Of 24,888 LTx, 80% had extended criteria; 42% had 2 or more extensions and were deemed ECD in this analysis. Both LTx volume (2005: 1352; 2018: 2495) and use of ECD (2005: 27% ECD, 2018: 50% ECD) have increased over the study period. Survival of LTx recipients has steadily increased (2005: 82% 1-year survival in 2005; 2017: 90% 1-year survival). High-volume centers (>47 annual LTx) utilized ECD in 46% of transplants compared with 40% ECD among other centers. Recipients of ECD and standard criteria organs had no difference in 1-year survival.

CONCLUSIONS

Donor supply limits the number of LTx performed. Extension of donor criteria has occurred alongside increased overall LTx volume. Use of ECD did not compromise 30-day, 90-day, nor 1-year survival. Further studies are warranted to define long-term outcomes.

Use of modified Custodiol-N as perfusion solution in ex vivo lung perfusion

OBJECTIVES

Ex vivo Lung Perfusion (EVLP) is a promising tool to increase the donor pool for lung transplantation. Custodiol-N solution was originally designed for organ preservation during cold static preservation (CSP) and was successfully used for machine perfusion in kidneys. It was the aim of this study to compare the lung functional outcomes after 4 hours of EVLP using modified Custodiol-N or STEEN Solution^TM as perfusion solution.

METHODS

In a porcine DCD model, lungs were perfused either with STEEN Solution^TM (Standard SS, n=8) or modified Custodiol-N with added 1.1 g/l glucose monohydrate and 50 g/l dextran 40 (CD, n=8). For a third group 7 g/l albumin was supplemented to modified Custodiol-N (CDA, n=8). During four hours of EVLP pulmonary gas exchange and activities of lactate dehydrogenase (LDH) and alkaline phosphatase (AP) in perfusate were recorded.

RESULTS

Lungs that underwent EVLP with modified Custodiol-N showed significantly higher oxygen capacity (ΔpO₂ averaged over four hours of EVLP: SS: 236.28 ± 47.26 mmHg, CD: 402.79 ± 30.33 mmHg, CDA: 414.86 ± 9.77 mmHg) than lungs perfused with STEEN Solution^TM. The addition of albumin did not have a significant effect on lung function but these lungs showed lower wet/dry ratio.

CONCLUSION

In a porcine DCD model of 9 hours CSP followed by four hours of EVLP the use of modified Custodiol-N as perfusion solution was feasible and associated with higher oxygen capacity than STEEN Solution^TM. The addition of albumin seems to further stabilize lung function.

Effects of immediate versus delayed ex-vivo lung perfusion in a porcine cardiac arrest donation model

OBJECTIVE

Ex-vivo lung perfusion is a promising tool to evaluate and recondition marginal donor lungs usually after a cold static preservation. The concept of continuous organ perfusion is supposed to reduce ischemic damage; however, the optimal perfusion protocol has not been established yet. The aim of this study was to compare immediate ex-vivo lung perfusion (I-EVLP) to delayed ex-vivo lung perfusion (D-EVLP) after a certain cold static preservation period on lung function in a large animal model.

METHODS

In a porcine model, lungs were procured after circulatory death and 60 min of no-touch warm ischemia. Lungs were preserved with single-flush cold low potassium dextran solution and prepared either for I-EVLP (n = 8) or stored cold for 9 h with subsequent D-EVLP (n = 8). Functional outcomes and morphology were compared during 4 h of ex-vivo lung perfusion, using STEEN Solution^TM as perfusion solution.

RESULTS

Pulmonary functional data, perfusate activities of lactate dehydrogenase, alkaline phosphatase, and products of lipid peroxidation did not differ significantly. There was a trend toward lower wet-dry ratio (I-EVLP: 13.4 ± 2.9; D-EVLP: 9.1 ± 2.5) and higher ΔpO₂ in D-EVLP group (I-EVLP: 209 ± 51.6 mmHg; D-EVLP: 236.3 ± 47.3 mmHg).

CONCLUSION

In this donation-after-circulatory-death model, 9 h of cold static preservation followed by ex-vivo lung perfusion results in comparable pulmonary function to I-EVLP as indicated by oxygenation capacities and wet-dry ratio. Our findings indicate that prolonged cold static preservation prior to ex-vivo lung perfusion is as safe and effective as I-EVLP in the procurement of donor lungs.

Vein Suturing Results in Worse Lung Graft Outcomes Compared to the Cuff Method

BACKGROUND

The rat orthotopic lung transplant model is not widely used yet because of the complexity of the procedure, in particular, venous anastomosis. Here, we performed a rat orthotopic lung transplantation using either the suture (ST) or cuff (CT) method for vein anastomosis.

OBJECTIVES

To compare the vein ST and CT techniques in terms of operative time, success, recipient survival, and early histological outcomes was the objective of this study.

METHODS

A total of 24 left lung transplants in rats were performed. Twelve syngeneic (Lewis to Lewis) and 12 allogeneic (Brown-Norway to Lewis) lung transplants were performed using either the vein ST or the CT procedure. Arterial and bronchial anastomoses were performed with the CT technique. Graft histological damage was evaluated 3-7 days post-transplant in all rat lungs.

RESULTS

The surgical success rate was 75% in both the ST and CT groups. Failures related mainly to vein bleeding (n = 2 in the ST group) and thrombosis (n = 1 in the ST group; n = 2 in the CT group). Total ischemia time was longer in the ST group (122 ± 25 min in ST group vs. 83 ± 10 min in CT group, mean ± SD), due to prolonged warm ischemia time (60 ± 12 min in the ST group vs. 21 ± 5 min in the CT group, mean ± SD), reflecting the time required to complete the vein ST procedure. The prolonged warm ischemia time resulted in significantly higher vascular inflammation in syngeneic grafts (2.3 ± 1.2 ST group vs. 0 in the CT group, mean ± SD) and in increased severity of ischemia/reperfusion injury and acute graft rejection (3.6 ± 0.4 in the ST group vs. 2.6 ± 0.4 in the CT group, mean ± SD) in allogeneic lung transplants.

CONCLUSIONS

The vein ST technique is a more time-consuming procedure than the CT method and the prolonged anastomosis time has a deleterious impact on transplant outcomes. These findings suggest that warm ischemia time - one of the modifiable transplant factors - should be considered a major risk factor in lung transplantation, particularly in the setting of donation after cardiac death.

A potential role of microvesicle-containing miR-223/142 in lung inflammation

BACKGROUND

Uncontrolled lung inflammation is one of the prominent features in the pathogenesis of lung infection- associated acute lung injury (ALI). Microvesicles (MVs) are extracellular nanovesicles that are generated via direct membrane budding.

METHODS

Bronchoalveolar lavage fluid (BALF) samples were collected from mice with or without intratracheal lipopolysaccharide (LPS) instillation. BALF MVs were characterised and MV-containing microRNA (miRNA) profiles were assessed and confirmed. Secretion and function of MV-containing miR-223/142 (MV-miR-223/142) were analysed in vivo.

RESULTS

In BALF, MVs are mainly derived from macrophages in response to LPS. After intratracheal instillation (i.t.) of LPS or Klebsiella pneumoniae, MV-containing miR-223/142 are dramatically induced in both BALF and serum. Mechanistically, miRNA 3' end uridylation mediates the packing of miR-223/142 into MVs. To investigate the functional role of MV-miR-223/142, we loaded miR-223/142 mimics into unstimulated MVs and delivered them into the murine lungs via i.t. The miR-223/142 mimics-enriched MVs selectively targeted lung macrophages and suppressed the inflammatory lung responses that were triggered by LPS or K. pneumoniae. Mechanistically, miR-223 and miR-142 synergistically suppress Nlrp3 inflammasome activation in macrophages via inhibition of Nlrp3 and Asc, respectively.

CONCLUSIONS

In the pathogenesis of lung macrophage-mediated inflammatory responses, MV-miR-223/142 secretion is robustly enhanced and detectable in BALF and serum. Furthermore, restoration of intracellular miR-223/142 via vesicle-mediated delivery suppresses macrophage activation and lung inflammation via inhibition of Nlrp3 inflammasome activation.

A Summary of Transplantation Activity in Hungary

The first kidney transplantation was performed in Hungary by András Németh in 1962. It was a living donor procedure. After many years of silence, organized cadaveric programs were established in Budapest (1973), Szeged (1979), Debrecen (1991), and Pécs (1993). The heart program was initiated by Professor Zoltán Szabó in 1992 and the liver transplant program by Professor Ferenc Perner in 1993. The pancreas transplantation program was started in Pécs in 1998 by Károly Kalmár-Nagy, followed another in Budapest by Robert Langer in 2004. The lung transplant program was started in cooperation with Vienna in 1996. This fruitful collaboration continues today, even though that the national Hungarian program was established by Ferenc Rényi-Vámos and Professor György Lang in 2015, as it is detailed in this special issue. As a framework, the Hungarian Society of Organ Transplantation was founded in 1997 to give a scientific background for the transplant professionals. The coordination and organ allocation from deceased donors is carried out in collaboration with Eurotransplant. Usually more than 200 potential cadaveric donors are reported yearly, and 168 actual donation after brain death (DBD) donors (17.17 pmp) were utilized in 2018. The multiorgan donor rate was 65.5% among all DBDs in 2018; 505 organs were donated for transplant purposes. To date, more than 10,000 organ transplantations have been performed. The living related kidney transplant program was established in all transplant centers, led by Budapest. In this paper the authors summarize the activity of the Hungarian transplant community and of the Society over the last few decades.