Cryobanking of Human Distal Lung Epithelial Cells for Preservation of Their Phenotypic and Functional Characteristics.

The epithelium lining airspaces of the human lung is maintained by regional stem cells, including basal cells of pseudostratified airways and alveolar type 2 (AT2) pneumocytes of the gas-exchange region. Despite effective techniques for long-term preservation of airway basal cells, procedures for efficient preservation of functional epithelial cell types of the distal gas-exchange region are lacking. Here we detail a method for cryobanking of epithelial cells from either mouse or human lung tissue for preservation of their phenotypic and functional characteristics. Flow cytometric profiling, epithelial organoid-forming efficiency, and single-cell transcriptomic analysis were used to compare cells recovered from cryobanked tissue with those of freshly dissociated tissue. AT2 cells within single-cell suspensions of enzymatically digested cryobanked distal lung tissue retained expression of the pan-epithelial marker CD326 and the AT2 cell surface antigen recognized by monoclonal antibody HT II-280, allowing antibody-mediated enrichment and downstream analysis. Isolated AT2 cells from cryobanked tissue were comparable with those of freshly dissociated tissue both in their single-cell transcriptome and their capacity for in vitro organoid formation in three-dimensional cultures. We conclude that the cryobanking method described herein allows long-term preservation of distal human lung tissue for downstream analysis of lung cell function and molecular phenotype and is ideally suited for the creation of an easily accessible tissue resource for the research community.

Robotic-assisted lung transplantation: First in man.

Lung transplantation remains the best option for patients with end-stage lung disease. However, this operation has historically carried significant potential morbidity. To improve near-term patient outcomes, attempts have been made to decrease invasiveness, but this is limited by the complex nature of the operation and the anatomy of the chest. To facilitate further reduction in incision size and augment our existing minimally invasive approach, we developed a novel technique utilizing the Da Vinci robotic system to implant a right lung in a 69-year-old recipient.

Centralized Static Ex-Vivo Lung Perfusion in the United States.

BACKGROUND: Ex-vivo lung perfusion (EVLP) may improve donor lung utilization but requires significant infrastructure and expertise. Centralized EVLP facilities may mitigate these requirements. METHODS: From the United Network for Organ Sharing database, we identified 345 adults undergoing isolated, first-time lung transplantation using donor lungs perfused by static EVLP (03/01/2018-12/31/2022). Recipients of lungs perfused at centralized EVLP facilities (n=165) were compared to recipients of lungs perfused at individual transplant centers (n=180). Propensity score matching was used to create balanced groups for comparison. RESULTS: Centralized EVLP facilities were increasingly utilized from 2018 to 2022 (35.3 vs. 55.8%, p=0.04) and were more likely used when the annual center volume of EVLP lung transplants was low. Compared to allografts placed on EVLP at individual transplant centers, those placed on EVLP at centralized facilities had longer median ischemic time (11.3 vs. 9.6 hours, p<0.001) and were less likely to come from donation after circulatory death donors (25.4 vs. 39.5%, p=0.003) or be used for double lung transplant (73.3 vs. 83.9%, p=0.02). In 102 well-matched recipients, 2-year survival was equivalent between those receiving allografts perfused at centralized facilities (77.9% [95% CI 68.0-85.1%]) versus individual transplant centers (77.7% [95% CI 67.8-84.9%], p=0.90). Multivariable Cox regression analysis also showed equivalent 2-year survival (adjusted hazard ratio 1.02, 95% CI 0.57-1.84, p=0.95). CONCLUSIONS: Transplanting lung allografts that underwent static EVLP at centralized facilities had similar outcomes compared to transplanting lungs perfused at individual transplant centers. The centralized model of clinical EVLP can potentially improve access to EVLP.

Impact of minimally invasive lung transplantation on early outcomes and analgesia use: A matched cohort study.

BACKGROUND: Minimally invasive (MI) approaches to lung transplantation (LTx) offer the prospect of faster recovery compared to traditional incisions, however, little data exist describing the impact of surgical technique on early outcomes and analgesia use. METHODS: A prospectively maintained institutional registry identified 170 patients who underwent LTx between January, 2017 and June, 2022. Post-COVID acute respiratory distress syndrome, repeat, and multiorgan transplants were excluded (n = 27) leaving 37 MILTx and 106 traditional LTx patients. Propensity score matching by age, sex, body mass index, diagnosis, lung allocation score, double vs. single lung, hypertension, diabetes, and hospitalization status created 37 pairs. RESULTS: Before matching, MILTx patients were more often male (70% vs 43%) and more likely to receive grafts from younger (31 vs 42 years), circulatory death donors (19% vs 6%) compared with traditional LTx patients (all p < 0.05). After matching, there were no differences in graft warm ischemia or operative duration (both p > 0.05). Postoperatively, MILTx experienced shorter intensive care unit (ICU) (4.3 [IQR 3.1-5.5] vs 8.2 [IQR 3.7-10.8] days) and hospital lengths of stay (LOS) (13 [IQR 11-15] vs 17 [IQR 12-25] days) (both p < 0.05). Among patients surviving to discharge, MILTx patients required fewer opioid prescriptions at discharge (38% vs 66%, p = 0.008) and had improved pulmonary function at 3 months (Forced expiratory volume in 1 second 82 [IQR 72-102] vs 77 [IQR 52-88]% predicted; forced vital capacity 78 [IQR 65-92] vs 70 [IQR 62-80]% predicted] (both p < 0.05). CONCLUSION: Minimally invasive LTx techniques demonstrate potential advantages over traditional approaches, including reduced ICU and hospital LOS, lower opioid use on discharge, and improved early pulmonary function.

Pearls & Oy-sters: Status Epilepticus and Cerebral Edema From Hyperammonemia Due to Disseminated Ureaplasma and Mycoplasma Species.

Nonhepatic hyperammonemia syndrome is a rare cause of neurologic dysfunction and cerebral edema and has most commonly been reported in posttransplant patients. Only recently has opportunistic infection with Ureaplasma species and Mycoplasma hominis been found to be key to the pathogenesis. We describe the cases of 3 immunosuppressed patients who developed hyperammonemia syndrome with new-onset refractory status epilepticus and diffuse cerebral edema. PCR was positive for M hominis in 1 patient and Ureaplasma parvum in the other 2. Despite early diagnostic suspicion and aggressive management with empirical antibiotics, seizure control, hypertonic saline, and ammonia elimination, none of our patients survived this life-threatening infection. Nonhepatic hyperammonemia and new-onset seizures can be presenting features of disseminated Ureaplasma species and M hominis infections in posttransplant patients. Immunosuppression in the absence of organ transplantation is likely sufficient to trigger this entity, as was the case in our third patient. When suspected, empiric combination antibiotics should be used due to high likelihood of resistance. The diagnostic test of choice is PCR. Patients with hyperammonemia syndrome associated with these infections typically have a poor prognosis. Early recognition and aggressive multimodal interventions may be key to ameliorating the high mortality and severe neurologic sequelae from this entity.

Real-time transcription polymerase chain reaction cycle threshold values as criteria for utilization of incidental COVID-19 positive lung donors.

Shortage of organ donors is an ongoing limiting factor in lung transplantation (LT). Despite increasing prevalence of asymptomatic COVID-19 infection, positive COVID-19 testing from a potential donor remains a contraindication at many LT centers. In this report, we present the outcomes of LT utilizing an algorithm based on donor clinical presentation, and COVID-19 real-time reverse transcription polymerase chain reaction (RT-PCR) with cycle threshold (Ct) values evaluation. The Ct value threshold for organ acceptance was >35. A total of 8 COVID-positive donors were included. No donor-to-recipient transmissions of COVID-19 were observed. Short-term outcomes were comparable to those reported in pre-COVID literature. Survival-to-date is 100% with median POD of 161 days. Our findings support the safety and efficacy of utilizing our algorithm including Ct value threshold for selection of donors with incidental COVID-19 positive testing.

Lung transplantation outcomes in patients from socioeconomically distressed communities.

BACKGROUND: Previous studies have demonstrated racial and gender disparities in lung allocation, but contemporary data regarding socioeconomic disparities in post-transplant outcomes are lacking. We evaluated the impact of a composite socioeconomic disadvantage index on post-transplant outcomes. METHODS: The Scientific Registry of Transplant Recipients identified 27,763 adult patients undergoing isolated primary lung transplantation between 2005 and 2020. Zip code-level socioeconomic distress was characterized using the Distressed Communities Index (DCI: 0-no distress, 100-severe distress) based on education level, poverty, unemployment, housing vacancies, median income, and business growth, and patients were stratified into high (DCI ≥60) or low (DCI <60) distressed groups. RESULTS: Recipients from high-distress communities (n = 8006, 28.8%) were younger (59years [interquartile range {IQR} 50-64] vs 61years [IQR 52-66]), less often white (73 vs 85%), less likely to have a college degree (45 vs 59%), and more likely to have public insurance (57 vs 49%, all p < 0.001) compared to those from low-distress communities. Additionally, high-distress recipients were more likely to have group A diagnoses (32 vs 27%) and undergo bilateral lung transplants (72.4 vs 69.3%, all p < 0.001). Post-transplant survival at 5years was 55.7% (95% confidence interval [CI]: 54.4-56.9) in high-distress recipients and 58.2% (95% CI: 57.4-58.9) in low-distress recipients (p = 0.003). After adjustment, high distress level was independently associated with an increased risk of 5-year mortality (hazard ratio:1.09, 95% CI:1.04-1.15). CONCLUSIONS: Recipients from distressed communities are at increased mortality risk following lung transplantation. Efforts should be focused on increased resource allocation and further study to better understand factors which may mitigate this disparity.

Simultaneous Lung-Kidney Transplantation in the United States.

BACKGROUND: Simultaneous lung-kidney transplantation is rarely performed. Contemporary national practice trends and outcomes are unclear. METHODS: From the United Network for Organ Sharing database, we identified 108 lung-kidney transplant recipients (2005-2022). They were compared with isolated lung recipients with pretransplantation dialysis or estimated glomerular filtration rate (eGFR) ≤30 mL/min per 1.73 m2 (n = 372) and isolated non-dialysis-dependent lung recipients with 30 < eGFR < 50 mL/min per 1.73 m2 (n = 1416), respectively. Lung-kidney recipients were also compared with recipients of the contralateral kidney from the same donors (n = 90). RESULTS: Lung-kidney transplantation was performed by 36 centers, with increasing annual volume (1 in 2005, 16 in 2022; P < .01). Forty percent (44/108) of lung-kidney recipients received pretransplantation dialysis, and of those without pretransplantation dialysis, median eGFR was 30.7 mL/min per 1.73 m2. Lung-kidney recipients had improved survival compared with isolated lung recipients with eGFR ≤30 mL/min per 1.73 m2 or pretransplantation dialysis (adjusted hazard ratio, 0.59; 95% CI, 0.38-0.92). However, no survival benefit was observed when lung-kidney recipients were compared with isolated lung recipients with 30 < eGFR < 50 mL/min per 1.73 m2 and no pretransplantation dialysis (adjusted hazard ratio, 0.88; 95% CI, 0.55-1.41). Compared with isolated kidney recipients using the contralateral kidney from the same donors, lung-kidney recipients had a higher risk of kidney allograft loss (adjusted hazard ratio, 3.27; 95% CI, 1.22-8.78), a difference largely accounted for by patient death with a functioning kidney allograft. CONCLUSIONS: Recipients of lung-kidney transplants had improved survival compared with isolated lung recipients with eGFR ≤30 mL/min per 1.73 m2 or pretransplantation dialysis. However, lung-kidney recipients had a higher rate of kidney allograft loss than recipients of the contralateral kidney allograft from the same donors.

Donor hyperoxia is a novel risk factor for severe cardiac primary graft dysfunction.

BACKGROUND: Primary graft dysfunction (PGD) is a major cause of early mortality following heart transplant (HT). Donor risk factors for the development of PGD are incompletely characterized. Donor management goals (DMG) are predefined critical care endpoints used to optimize donors. We evaluated the relationship between DMGs as well as non-DMG parameters, and the development of PGD after HT. METHODS: A cohort of HT recipients from 2 transplant centers between 1/1/12 and 12/31/19 was linked to their respective donors in the United Network for Organ Sharing (UNOS) DMG Registry (n = 1,079). PGD was defined according to modified ISHLT criteria. Variables were subject to univariate and multivariable multinomial modeling with development of mild/moderate or severe PGD as the outcome variable. A second multicenter cohort of 4,010 donors from the DMG Registry was used for validation. RESULTS: Mild/moderate and severe PGD occurred in 15% and 6% of the cohort. Multivariable modeling revealed 6 variables independently associated with mild/moderate and 6 associated with severe PGD, respectively. Recipient use of amiodarone plus beta-blocker, recipient mechanical circulatory support, donor age, donor fraction of inspired oxygen (FiO2), and donor creatinine increased risk whereas predicted heart mass ratio decreased risk of severe PGD. We found that donor age and FiO2 ≥ 40% were associated with an increased risk of death within 90 days post-transplant in a multicenter cohort. CONCLUSIONS: Donor hyperoxia at heart recovery is a novel risk factor for severe primary graft dysfunction and early recipient death. These results suggest that excessive oxygen supplementation should be minimized during donor management.

A randomized controlled trial of presatovir for respiratory syncytial virus after lung transplant.

BACKGROUND: Respiratory syncytial virus (RSV) infection in lung transplant recipients is associated with high morbidity. This study evaluated the RSV fusion inhibitor presatovir in RSV-infected lung transplant recipients. METHODS: In this international Phase 2b, randomized, double-blind, placebo-controlled trial (NCT02534350), adult lung transplant recipients with symptomatic confirmed RSV infection for ≤7 days received oral presatovir 200 mg on day 1 and 100 mg daily on days 2 to 14, or placebo (2:1), with follow-up through day 28. There were 2 coprimary endpoints: time-weighted average change in nasal RSV load from day 1 to 7, calculated from nasal swabs, in the full analysis set ([FAS]; all patients who received study drug and had quantifiable baseline nasal RSV load) and time-weighted average change in nasal RSV load from day 1 to 7 in the subset of patients with pretreatment symptom duration at the median or shorter of the FAS. Secondary endpoints were changes in respiratory infection symptoms assessed using the Influenza Patient-Reported Outcomes questionnaire and lung function measured by spirometry. RESULTS: Sixty-one patients were randomized, 40 received presatovir, 20 placebo, and 54 were included in efficacy analyses. Presatovir did not significantly improve the primary endpoint in the FAS (treatment difference [95% CI], 0.10 [-0.43, 0.63] log10 copies/ml; p = 0.72) or the shorter symptom-duration subgroup (-0.12 [-0.94, 0.69] log10 copies/ml; p = 0.76). Secondary endpoints were not different between presatovir and placebo groups. Presatovir was generally well tolerated. CONCLUSIONS: Presatovir treatment did not significantly improve change in nasal RSV load, symptoms, or lung function in lung transplant recipients.

Using Bronchoscopic Lung Cryobiopsy and a Genomic Classifier in the Multidisciplinary Diagnosis of Diffuse Interstitial Lung Diseases.

BACKGROUND: Challenges remain for establishing a specific diagnosis in cases of interstitial lung disease (ILD). Bronchoscopic lung cryobiopsy (BLC) has impacted the diagnostic impression and confidence of multidisciplinary discussions (MDDs) in the evaluation of ILD. Reports indicate that a genomic classifier (GC) can distinguish usual interstitial pneumonia (UIP) from non-UIP. RESEARCH QUESTION: What is the impact of sequentially presented data from BLC and GC on the diagnostic confidence of MDDs in diagnosing ILD? STUDY DESIGN AND METHODS: Two MDD teams met to discuss 24 patients with ILD without a definitive UIP pattern. MDD1 sequentially reviewed clinical-radiologic findings, BLC, and GC. MDD2 sequentially reviewed GC before BLC. At each step in the process the MDD diagnosis and confidence level were recorded. RESULTS: MDD1 had a significant increase in diagnostic confidence, from 43% to 93% (P = .023), in patients with probable UIP after the addition of GC to BLC. MDD2 had an increase in diagnostic confidence, from 27% to 73% (P = .074), after the addition of BLC to GC. The concordance coefficients and percentage agreement of categorical idiopathic pulmonary fibrosis (IPF) and non-IPF diagnoses were as follows: GC vs MDD1: 0.92, 96%; GC vs MDD2: 0.83, 92%; BLC1 vs MDD1: 0.67, 83%; BLC2 vs MDD2: 0.66, 83%. INTERPRETATION: GC increased diagnostic confidence when added to BLC for patients with a probable UIP pattern, and in appropriate clinical settings can be used without BLC. In contrast, BLC had the greatest impact regarding a specific diagnosis when the likelihood of UIP was considered low following clinical-radiographic review.

Lung Transplantation and the Routine Use of Cardiopulmonary Bypass and Median Sternotomy: Experience at the Ochsner Multi-Organ Transplant Institute.

BACKGROUND: From 1990-2005 at Ochsner Medical Center in New Orleans, LA, cardiopulmonary bypass (CPB) was used only when necessary during lung transplantation surgeries. Ochsner's lung transplant program was closed for more than 4 years after Hurricane Katrina, and since the program's reestablishment in 2010, the majority of lung transplantation surgeries have been performed with the patient on CPB and with a median sternotomy incision. The purpose of this study was to compare the outcomes of the CPB and non-CPB groups. METHODS: After institutional review board approval, we conducted a retrospective review of the entire program using the Ochsner lung transplant database to identify patients in the non-CPB group from 1990-2005 and in the CPB group from 2010-2014. We calculated 1- and 3-year survival rates for each patient and reviewed medical records for evidence of stroke, the need for operative reexploration, and venous stenosis. We also performed a subgroup analysis of the first 20 consecutive patients undergoing lung transplantation on CPB with median sternotomy from February 2010 through April 2011 to examine intraoperative blood product use, the quantity of blood products administered, CPB cannulation and pump complications, ischemic time, and primary graft dysfunction. RESULTS: Of the 208 patients in the non-CPB group, 74% had 1-year graft survival and 55% had 3-year survival following transplantation. After February 2010, 79 patients underwent lung transplantation on CPB with median sternotomy, and 90% of those patients had 1-year graft survival. Of the 46 patients available for 3-year follow-up, 59% were alive with functional grafts. The difference in 1-year survival rates between the 2 cohorts was statistically significant. Two deaths, 3 strokes, and 5 reexplorations of the chest for bleeding occurred during the perioperative time period in the CPB group, but no mortality was associated with these perioperative events. One patient who had perioperative complications died within the first year; the death was attributable to gastric perforation. CONCLUSION: Patients' early outcomes appear to have improved with the use of CPB and median sternotomy; however, 3-year survival is similar to the non-CPB group. Technical benefits of CPB with median sternotomy include decreased warm ischemia time during graft implantation, controlled hemodynamics and reperfusion, avoidance of single-lung ventilation of a freshly implanted graft, and the option to open the left atrium for implantation of a venous cuff without using a clamp. The surgical exposure facilitated by CPB with median sternotomy for lung transplantation appears to be a safe and feasible approach for lung transplantations.

Lung transplantation: an overview of candidacy and outcomes.

BACKGROUND: Various factors must be taken into account when considering lung transplantation, including candidacy, contraindications, and outcomes. METHODS: This article presents a review of the data and literature on lung transplantation, tracking the evolution of the treatment as it applies to different conditions, as well as an examination of patient survival rates in relation to pathology and treatment. RESULTS: Timely referral and careful selection of candidates for lung transplantation maximize the outcomes of the procedure, resulting in a longer lifespan with improved physical health for patients. CONCLUSION: Lung transplantation is a therapeutic option for patients with various lung diseases. Adapting treatment options and follow-up treatment to the individual patient's lifestyle and pathology optimizes patient survival rates after transplantation.