Impaired esophagogastric junction relaxation and lung transplantation outcomes

The implications of impaired esophagogastric junction relaxation (i.e. esophagogastric junction outflow obstruction and achalasia) in lung transplants recipients (LTRs) are unclear. Thus, we examined the prevalence and clinical outcomes of LTRs with an abnormally elevated integrated relaxation pressure (IRP) on high-resolution manometry before lung transplantation (LTx). After IRB approval, we reviewed data on LTRs who underwent LTx between January 2019 and August 2022 with a preoperative median IRP >15 mmHg. Differences in overall survival and chronic lung allograft dysfunction (CLAD)-free survival between LTRs with a normalized median IRP after LTx (N-IRP) and those with persistently high IRP (PH-IRP) were assessed using Kaplan-Meier curves and the log-rank test. During the study period, 352 LTx procedures were performed; 44 (12.5%) LTRs had an elevated IRP before LTx, and 37 (84.1%) completed a postoperative manometry assessment (24 [70.6%] males; mean age, 65.2 ± 9.1 years). The median IRP before and after LTx was 18.7 ± 3.8 mmHg and 12 ± 5.6 mmHg, respectively (P < 0.001); the median IRP normalized after LTx in 24 (64.9%) patients. Two-year overall survival trended lower in the N-IRP group than the PH-IRP group (77.2% vs. 92.3%, P = 0.086), but CLAD-free survival (P = 0.592) and rates of primary graft dysfunction (P = 0.502) and acute cellular rejection (P = 0.408) were similar. An abnormally elevated IRP was common in LTx candidates; however, it normalized in roughly two-thirds of patients after LTx. Two-year survival trended higher in the PH-IRP group, despite similar rates of primary graft dysfunction and acute cellular rejection as well as similar CLAD-free survival between the groups.

Pulmonary and esophageal function in lung transplantation: Fundamental principles and clinical application

The lungs and esophagus have a close anatomical and physiological relationship. Over the years, reflux-induced pulmonary injury has gained wider recognition, but the full effects of pulmonary disease on esophageal function are still unknown. Intrathoracic pressure dynamics potentially affect esophageal function, especially in patients with end-stage lung disease, both obstructive and restrictive. Lung transplantation is the only viable option for patients with end-stage pulmonary disease and has provided us with a unique opportunity to study these effects as transplantation restores the intrathoracic environment. Esophageal and foregut functional testing before and after transplantation provide insights into the pathophysiology of the foregut-pulmonary axis, such as how underlying pulmonary disease and intrathoracic pressure changes affect esophageal physiology. This review summarizes the available literature and shares the research experience of a lung transplant center, covering topics such as pre- and posttransplant foregut function, esophageal motility in lung transplant recipients, immune-mediated mechanisms of graft rejection associated with gastroesophageal reflux, and the role of antireflux surgery in this population.

Assessment of the well-being of significant others of cardiothoracic surgeons

OBJECTIVES

We aimed to evaluate how the current working climate of cardiothoracic surgery and burnout experienced by cardiothoracic surgeons influences their spouses and significant others (SOs).

METHODS

A 33-question well-being survey was developed by the American Association for Thoracic Surgery Wellness Committee and distributed by e-mail to the SOs of cardiothoracic surgeons and to all surgeon registrants of the 2020 and 2021 American Association for Thoracic Surgery Annual Meetings with a request to share it with their SO. The 5-item Likert-scale survey questions were dichotomized, and associations were determined by χ2 or independent samples t tests, as appropriate.

RESULTS

Responses from 238 SOs were analyzed. Sixty-six percent reported that the stress on their cardiothoracic surgeon partner had a moderate to severe influence on their family, and 63% reported that their partner's work demands didn't leave enough time for family. Fifty-one percent reported that their partner rarely had time for intimacy, 27% reported poor work-life balance, and 23% reported that interactions at home were usually or always not good-natured. SOs were most affected when their partner was <5 years out from training, worked in private vs academic practice, and worked longer hours. Having children, particularly younger than age 19 years, and a lack of workplace support resources further diminished well-being.

CONCLUSIONS

The current work culture of cardiothoracic surgeons adversely affects their SOs, and the risk for families is concerning. These data present a major area for exploration as we strive to understand and mitigate the factors that lead to burnout among cardiothoracic surgeons.

Immune responses of lung transplant recipients against SARS-CoV-2 and common respiratory coronaviruses: Evidence for pre-existing cross-reactive immunity

Humoral and cellular immune responses to SARS-CoV-2 and other coronaviruses in lung transplant recipients are unknown. We measured antibodies and T cell responses against the SARS-CoV-2 spike S2 and nucleocapsid antigens and spike antigens from common respiratory coronaviruses (229E, NL63, OC43, and HKU1) after vaccination or infection of LTxRs. 148 LTxRs from single center were included in this study: 98 after vaccination and 50 following SARS-CoV-2 infection. Antibodies were quantified by enzyme-linked immunosorbent assay. The frequency of T cells secreting IL2, IL4, IL10, IL17, TNFα, and IFNγ were enumerated by enzyme-linked immunospot assay. Our results have shown the development of antibodies to SARS-CoV-2 spike protein in infected LTxRs (39/50) and vaccinated LTxRs (52/98). Vaccinated LTxRs had higher number of T cells producing TNFα but less cells producing IFNγ than infected LTxRs in response to the nucleocapsid antigen and other coronavirus spike antigens. We didn't find correlation between the development of antibodies and cellular immune responses against the SARS-CoV-2 spike protein after vaccination. Instead, LTxRs have pre-existing cellular immunity to common respiratory coronaviruses, leading to cross-reactive immunity against SARS-CoV-2 which likely will provide protection against SARS-Cov-2 infection.

Diagnosis and management of anastomotic leaks after Ivor Lewis esophagectomy: a single-center experience

PURPOSE

Esophageal anastomotic leaks (ALs) after esophagectomy are a common and serious complication. The incidence, diagnostic approach, and management have changed over time. We described the diagnosis and management of patients who developed an esophageal AL after an Ivor Lewis esophagectomy at our center.

METHODS

After IRB approval, we queried our prospectively maintained database for patients who developed an esophageal AL after esophagectomy from August 2016 through July 2022. Data pertaining to demographics, comorbidities, surgical and oncological characteristics, and clinical course were extracted and analyzed.

RESULTS

During the study period, 145 patients underwent an Ivor Lewis esophagectomy; 10 (6.9%) developed an AL, diagnosed a median of 7.5 days after surgery, and detected by enteric contents in wound drains (n = 3), endoscopy (n = 3), CT (n = 2), and contrast esophagogram (n = 2). Nine patients (90%) had an increasing white blood cell count and additional signs of sepsis. One asymptomatic patient was identified by contrast esophagography. All patients received enteral nutritional support, intravenous antibiotics, and antifungals. Primary treatment of ALs included endoscopic placement of a self-expanding metal stent (SEMS; n = 6), surgery (n = 2), and SEMS with endoluminal vacuum therapy (n = 2). One patient required surgery after SEMS placement. The median length of ICU and total hospital stays were 11.5 and 22.5 days, respectively. There was no 30-day mortality.

CONCLUSION

The incidence of esophageal ALs at our center is similar to that of other high-volume centers. Most ALs can be managed without surgery; however, ALs remain a significant source of postoperative morbidity despite clinical advancements that have improved mortality.

Cytosolic EpCAM cooperates with H-Ras to regulate epithelial to mesenchymal transition through ZEB1

Next generation sequencing of human cancer mutations has identified novel therapeutic targets. Activating Ras oncogene mutations play a central role in oncogenesis, and Ras-driven tumorigenesis upregulates an array of genes and signaling cascades that can transform normal cells into tumor cells. In this study, we investigated the role of altered localization of epithelial cell adhesion molecule (EpCAM) in Ras-expressing cells. Analysis of microarray data demonstrated that Ras expression induced EpCAM expression in normal breast epithelial cells. Fluorescent and confocal microscopy showed that H-Ras mediated transformation also promoted epithelial-to-mesenchymal transition (EMT) together with EpCAM. To consistently localize EpCAM in the cytosol, we generated a cancer-associated EpCAM mutant (EpCAM-L240A) that is retained in the cytosol compartment. Normal MCF-10A cells were transduced with H-Ras together with EpCAM wild-type (WT) or EpCAM-L240A. WT-EpCAM marginally effected invasion, proliferation, and soft agar growth. EpCAM-L240A, however, markedly altered cells and transformed to mesenchymal phenotype. Ras-EpCAM-L240A expression also promoted expression of EMT factors FRA1, ZEB1 with inflammatory cytokines IL-6, IL-8, and IL1. This altered morphology was reversed using MEK-specific inhibitors and to some extent JNK inhibition. Furthermore, these transformed cells were sensitized to apoptosis using paclitaxel and quercetin, but not other therapies. For the first time, we have demonstrated that EpCAM mutations can cooperate with H-Ras and promote EMT. Collectively, our results highlight future therapeutic opportunities in EpCAM and Ras mutated cancers.

Downregulation of a tumor suppressor gene LKB1 in lung transplantation as a biomarker for chronic murine lung allograft rejection

BACKGROUND

We recently demonstrated decreased tumor suppressor gene liver kinase B1 (LKB1) level in lung transplant recipients diagnosed with bronchiolitis obliterans syndrome. STE20-related adaptor alpha (STRADα) functions as a pseudokinase that binds and regulates LKB1 activity.

METHODS

A murine model of chronic lung allograft rejection in which a single lung from a B6D2F1 mouse was orthotopically transplanted into a DBA/2J mouse was employed. We examined the effect of LKB1 knockdown using CRISPR-CAS9 in vitro culture system.

RESULTS

Significant downregulation of LKB1 and STRADα expression was found in donor lung compared to recipient lung. STRADα knockdown significantly inhibited LKB1, pAMPK expression but induced phosphorylated mammalian target of rapamycin (mTOR), fibronectin, and Collagen-I, expression in BEAS-2B cells. LKB1 overexpression decreased fibronectin, Collagen-I, and phosphorylated mTOR expression in A549 cells.

CONCLUSIONS

We demonstrated that downregulation of LKB1-STRADα pathway accompanied with increased fibrosis, results in development of chronic rejection following murine lung transplantation.

Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury. Notably, aged human-Igfbp2 transgenic mice reveal reduced senescence and senescent-associated secretory phenotype factors in alveolar epithelial type 2 (AEC2) cells and they ameliorated bleomycin-induced lung fibrosis. Finally, we demonstrate that IGFBP2 expression is significantly suppressed in AEC2 cells isolated from fibrotic lung regions of patients with IPF and/or pulmonary hypertension compared with patients with hypersensitivity pneumonitis and/or chronic obstructive pulmonary disease. Altogether, our study provides insights into how IGFBP2 regulates AEC2-cell-specific senescence and that restoring IGFBP2 levels in fibrotic lungs can prove effective for patients with IPF.

Antireflux surgery versus medical management of gastro-oesophageal reflux after lung transplantation

OBJECTIVES

Gastro-oesophageal reflux disease after lung transplantation may be associated with chronic lung allograft dysfunction. Aspiration may continue on medical management of reflux, but antireflux surgery potentially reduces all reflux. We compared outcomes between medical and surgical management of reflux in lung recipients.

METHODS

Lung recipients with an elevated DeMeester score (≥14.72) on post-transplant reflux testing between 2015 and 2020 were included. Patients were divided into 2 groups: group A (underwent surgery) and group B (medically managed). Endpoints were pulmonary function, allograft dysfunction-free survival and overall survival. Further analysis included subgroups: A1 (early surgery, <6 months) and A2 (late surgery, >6 months), and B1 (DeMeester <29.9) and B2 (DeMeester ≥30).

RESULTS

A total of 186 included subjects were divided into groups A [n = 46 (A1, n = 36; A2, n = 10)] and B [n = 140 (B1, n = 78; B2, n = 62)]. Compared to medically managed patients, patients who underwent surgery had a higher prevalence of hiatal hernia (P < 0.001) and a lower prevalence of oesophageal motility disorders (P = 0.036). Recipients who underwent surgery had superior pulmonary function at 5 years compared to group B (P < 0.05) and longer allograft dysfunction-free survival than subgroup B2 (P = 0.028). Furthermore, early surgery was associated with longer survival than late surgery (P = 0.021).

CONCLUSIONS

Antireflux surgery in recipients with reflux improved long-term allograft function, and early surgery showed a survival benefit. Allograft dysfunction-free survival of lung recipients who underwent surgery was significantly better than that of medically managed patients with DeMeester ≥30. We present an algorithm for appropriate selection of candidates for antireflux surgery after lung transplantation.

A potential mechanism by which aspiration of duodenogastric fluid augments the risk for bronchiolitis obliterans syndrome after lung transplantation

OBJECTIVE

Aspiration of duodenogastric refluxate may damage the respiratory epithelium of lung allografts in transplant recipients. We sought to define a mechanism by which aspiration of duodenogastric fluid augments the risk of bronchiolitis obliterans syndrome after lung transplant in a murine model.

METHODS

We analyzed the immunological effects of acute aspiration of duodenogastric fluid (0.5 mL/kg) on transplant naive (strain DBA/2J) and transplanted mice (strain B6D2F1/J to strain DBA/2J). Serum antibodies to the lung self-antigens (SAgs) K-alpha1 tubulin and collagen-V were determined by enzyme-linked immunosorbent assay. Exosomes were isolated from serum, and immunoblot membranes were probed for antibodies to lung SAgs. Lung sections were assessed for fibrotic burden and obliterative bronchiolitis lesions by histologic and immunohistochemical analyses, including trichrome staining.

RESULTS

Transplanted mice that received duodenogastric fluid developed higher levels of antibodies to the lung SAgs K-alpha1 tubulin and collagen-V and exosomes with lung SAgs on posttransplant days 14 and 28 than transplanted mice with sham aspiration or transplant naive mice (with and without aspiration). All lung allografts demonstrated severe grade A4 rejection on posttransplant day 14, with the highest mean fibrotic burden and mean number of obliterative bronchiolitis-like lesions per microscopic field on day 28 in recipients with aspiration.

CONCLUSIONS

This study links aspiration of duodenogastric fluid after lung transplant to higher autoimmune responses to lung SAgs and the release of circulating exosomes with lung SAgs, which together promote sustained immune responses leading to extensive lung parenchymal damage and, ultimately, severe obliterative bronchiolitis-the histologic hallmark of bronchiolitis obliterans syndrome.

Hospitalized patients with irreversible lung injury from COVID-19 have higher morbidity but similar 1-year survival after lung transplant compared to hospitalized patients transplanted for restrictive lung disease

BACKGROUND

Hospitalized lung transplant (LT) recipients (LTRs) have higher post-LT morbidity and mortality than those who are well enough to wait for transplant at home. Outcomes after LT for COVID-19-associated acute respiratory distress syndrome (CARDS) may be even worse; thus, we compared post-LT outcomes between hospitalized LTRs transplanted for CARDS and those transplanted for restrictive lung disease (RLD).

METHODS

Between 2014 and 2021, hospitalized LTRs ≥18 years old with CARDS or RLD were included. Primary and secondary outcomes were 1-year post-LT survival and postoperative morbidity. For each patient in the CARDS group, an analysis of 1-to-1 matched patients from the RLD group was performed using logistic regression modeling.

RESULTS

Of 764 LTRs, 163 (21.3%) were hospitalized at the time of LT; 132 met the inclusion criteria: 11 (8.3%) were transplanted for CARDS and 121 (91.7%) for RLD. LTRs with CARDS were younger with longer pre-LT hospitalization stays and higher rates of pretransplant mechanical ventilation, dialysis, and ECMO as a bridge to transplant. A propensity-matched analysis demonstrated comparable rates of intrathoracic adhesions, posttransplant duration of mechanical ventilation, PGD3 at 72 hours, and delayed chest closure. Compared to LTRs with RLD, those with CARDS had significantly longer posttransplant hospital stays and a higher prevalence of ACR ≥A2 and DSA >2000 MFI, but comparable 1-year survival rates.

CONCLUSION

Even with careful selection, LT for patients with CARDS was associated with significant morbidity; however, 1-year survival of recipients with CARDS was comparable to that of matched hospitalized recipients with RLD.

Association Between Antibodies Against Lung Self-Antigens and Gastroesophageal Reflux in Lung Transplant Candidates

Gastroesophageal reflux (GER) and pretransplant antibodies against lung self-antigens (SAbs) collagen-V and/or k-alpha 1 tubulin are both independently associated with allograft dysfunction after lung transplantation (LTx). The role of GER in inducing lung injury and SAbs is unknown. We aimed to study the association between pre-LTx GER and SAbs. After IRB approval, we retrieved SAb assays conducted between 2015 and 2019 and collected 24 hour GER data for these patients. Patients were divided into 2 groups: no reflux (GER-) and pathologic reflux (GER+) to compare the prevalence of SAbs. Multivariate analysis was used to study the association between GER and SAbs in the whole cohort and in restrictive lung disease (RLD) and obstructive lung disease (OLD) subsets. Proximal esophageal reflux (PER) events ≥5 was considered abnormal. Patients (n = 134; 73 men) were divided into groups: GER- (54.5%, n = 73) and GER+ (45.5%, n = 61). The prevalence of GER was higher in the RLD than in the OLD subset (p < 0.001). The overall prevalence of SAbs was 53.7% (n = 72), higher in the GER+ than the GER- group (65.6% vs 43.8%, p = 0.012), but comparable between RLD and OLD subsets. Overall, SAbs were associated with GER (p = 0.012) and abnormal PER (p = 0.017). GER and abnormal PER increased the odds of SAbs in the RLD subset (OR [95% CI]: 2.825 [1.033-7.725], p = 0.040 and OR [95% CI]: 3.551 [1.271-9.925], p = 0.014, respectively) but not in the OLD subset. LTx candidates have a high prevalence of SAbs, which are significantly associated with GER and abnormal PER in patients with RLD.

Morbidity of antireflux surgery in lung transplant and matched nontransplant cohorts is comparable

BACKGROUND

Safety data on perioperative outcomes of laparoscopic antireflux surgery (LARS) after lung transplantation (LT) are lacking. We compared the 30-day readmission rate and short-term morbidity after LARS between LT recipients and matched nontransplant (NT) controls.

METHODS

Adult patients who underwent LARS between January 1, 2015, and October 31, 2021, were included. The participants were divided into two groups: LT recipients and NT controls. First, we compared 30-day readmission rates after LARS between the LT and NT cohorts. Next, we compared 30-day morbidity after LARS between the LT cohort and a 1-to-2 propensity score-matched NT cohort.

RESULTS

A total of 1328 patients (55 LT recipients and 1273 NT controls) were included. The post-LARS 30-day readmission rate was higher in LT recipients than in the overall NT controls (14.5% vs. 2.8%, p < 0.001). Compared to matched NT controls, LT recipients had a lower prevalence of paraesophageal hernia, a smaller median hernia size, and higher peristaltic vigor. Also compared to the matched NT controls, the LT recipients had a lower median operative time but a longer median length of hospital stay. The proportion of patients with a post-LARS event within 30 postoperative days was comparable between the LT and matched NT cohorts (21.8% vs 14.5%, p = 0.24).

CONCLUSIONS

Despite a higher perceived risk of comorbidity burden, LT recipients and matched NT controls had similar rates of post-LARS 30-day morbidity at our large-volume center with expertise in transplant and foregut surgery. LARS after LT is safe.

Incidentally Detected Malignancies in Lung Explants

Introduction: Incidentally detected malignancies in lung explants portend risk of early cancer recurrence and metastases with posttransplant immunosuppression. We present a series of lung transplant recipients with previously unverified malignancies in native lung explants. Design: We reviewed the histopathology, radiographic imaging, and management of lung explant malignancies at our institution over 10 years (2011-2020). Endpoints were survival and allograft rejection. Results: An explant malignancy was found in 1.3% (11/855) of lung transplant recipients (6 [55%] men; median age 68 years; 6 [55%] ex-smokers [median pack-years, 25]). Nine (82%) were adenocarcinoma, 1 (9%) was squamous cell carcinoma (SCC), and 1 (9%) was follicular lymphoma. Three patients (27%) had multifocal involvement (≥3 lobes), 4 (36%) had nodal involvement, and the median (range) tumor size was 2.7 (0.4-19) cm. The median interval between last imaging and transplant was 58 (29-144) days. Mycophenolate mofetil was discontinued or reduced in all; everolimus was used in 2 patients, and cisplatin-pemetrexed chemotherapy was used in 2 patients. The prevalence of acute cellular rejection and chronic rejection was 27% and 9%, respectively. Lung recipients with cancer had significantly lower survival than those without (36.4% vs 67.3%, p = 0.002); median survival was 27 (17, 65) months in 4 recipients who were alive and cancer-free at the end of the study period. Conclusions: Unidentified malignancies, commonly adenocarcinoma, can be detected in explanted native lungs. Pneumonectomy may be curative in SCC, lymphoproliferative disorders, and stage I adenocarcinoma. Modulating immunosuppression to prevent allograft rejection and tumor proliferation is warranted.

Well-being of Cardiothoracic Surgeons in the Time of COVID-19: A Survey by the Wellness Committee of the American Association for Thoracic Surgery

The prevalence of burnout among physicians has been increasing over the last decade, but data on burnout in the specialty of cardiothoracic surgery are lacking. We aimed to study this topic through a well-being survey. A 54-question well-being survey was developed by the Wellness Committee of the American Association for Thoracic Surgery (AATS) and sent by email from January through March of 2021 to AATS members and participants of the 2021 annual meeting. The 5-item Likert-scale survey questions were dichotomized, and associations were determined by Chi-square tests or independent samples t-tests, as appropriate. The results from 871 respondents (17% women) were analyzed. Many respondents reported at least moderately experiencing: 1) a sense of dread coming to work (50%), 2) physical exhaustion at work (58%), 3) a lack of enthusiasm at work (46%), and 4) emotional exhaustion at work (50%). Most respondents (70%) felt that burnout affected their personal relationships at least "some of the time," and many (43%) experienced a great deal of work-related stress. Importantly, most respondents (62%) reported little to no access to workplace resources for emotional support, but those who reported access reported less burnout. Most respondents (57%) felt that the COVID-19 pandemic has negatively affected their well-being. On a positive note, 80% felt their career was fulfilling and enjoyed their day-to-day job at least "most of the time." Cardiothoracic surgeons experience high levels of burnout, similar to that of other medical professionals. Interventions aimed at mitigating burnout in this profession are discussed.

Surgical Complications of Lung Transplantation

Lung transplantation is a life-saving intervention and the most effective therapy for select patients with irreversible lung disease. Despite the effectiveness of lung transplantation, it is a major operation with several opportunities for complications. For example, recipient and donor factors, technical issues, early postoperative events, and immunology can all contribute to potential complications. This article highlights some of the key surgery-related complications that can undermine a successful lung transplantation. The authors offer their expert opinion and experience to help practitioners avoid such complications and recognize and treat them early should they occur.

Novel role for tumor suppressor gene, liver kinase B1, in epithelial-mesenchymal transition leading to chronic lung allograft dysfunction

Epithelial-mesenchymal transition (EMT) has been implicated to play a role in chronic lung allograft dysfunction (CLAD). Liver kinase B1 (LKB1), a tumor suppressor gene, can regulate EMT. However, its role in CLAD development following lung transplantation remains unknown. Using qRT-PCR, biopsies from lung transplant recipients with bronchiolitis obliterans syndrome (BOS) demonstrated significant downregulation of LKB1 (p = .0001), compared to stable biopsies. To determine the role of LKB1 in EMT development, we analyzed EMT in human bronchial epithelial cell line BEAS-2B. Knockdown of LKB1 by siRNA significantly dysregulated mesenchymal markers expression in BEAS-2B cells. Following incubation of human primary bronchial epithelial cell or BEAS-2B cells with exosomes isolated from BOS or stable lung transplant recipients, LKB1 expression was inhibited when incubated with BOS-exosome. Incubation with BOS-exosomes also decreased LKB1 expression and induced EMT markers in air-liquid interface culture method. Our results provide novel evidence that exosomes released from transplanted lungs undergoing chronic rejection are associated with inactivated tumor suppressor gene LKB1 and this loss induces EMT leading to the pathogenesis of CLAD following human lung transplantation.

Lung Transplant Candidates With Pretransplant Gastroesophageal Reflux and Antibodies to Lung Self-antigens Have Shorter CLAD-free Survival After Transplant

Pre–lung transplant (LTx) gastroesophageal reflux (GER) and circulating antibodies against the lung self-antigens (SAbs) collagen V and K-alpha-1 tubulin may predispose recipients to chronic lung allograft dysfunction (CLAD). We aimed to study the association of pre-LTx GER or pre-LTx SAbs with CLAD.

Restrictive allograft syndrome vs bronchiolitis obliterans syndrome: Immunological and molecular characterization of circulating exosomes

BACKGROUND

Chronic lung allograft dysfunction in lung transplant recipients (LTxRs) has 2 phenotypes: obstructive bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Our goal was to define distinct immunologic markers of exosomes from LTxRs with BOS or RAS.

METHODS

Plasma was collected from LTxRs with BOS (n = 18), RAS (n = 13), and from stable LTxRs (n = 5). Antibodies to lung self-antigens (SAgs) were determined by ELISA. Exosomes were isolated by ultracentrifugation. Donor specific antibodies to HLA were quantified using Luminex. Exosomes were characterized for lung SAgs, transcription factors, 20S proteasome, HLA class I and II, and polymeric immunoglobulin receptor protein using western blot. Exosome miRNA was analyzed using NanoString. The exosome-induced immune response was determined in mice.

RESULTS

LTxRs with RAS, but not BOS, had donor specific antibodies at diagnosis. CIITA, NFkB, polymeric immunoglobulin receptor protein, 20S proteasome, HLA-DQ, and HLA-DR were significantly higher in RAS exosomes than in BOS exosomes. RAS plasma had high levels of proinflammatory cytokines and distinct exosomal miRNA. Immunization of C57BL/6 mice with RAS exosomes showed severe inflammation and peribronchial fibrosis, whereas BOS exosomes induced patchy inflammation and fibrosis.

CONCLUSION

LTxRs with BOS or RAS had exosomes with distinct molecular and immunologic profiles. RAS samples had a higher concentration of proinflammatory factors, HLA class II, lung SAgs, and antibodies to HLA class II molecules, indicating severe allograft injury. Mice immunized with RAS exosomes developed lesions in airways, pleura, interlobular septum, and alveoli, whereas BOS exosomes induced mild to patchy inflammation with lung fibrosis.

A decline in club cell secretory proteins in lung transplantation is associated with release of natural killer cells exosomes leading to chronic rejection

BACKGROUND

In human lung transplant recipients, a decline in club cell secretory protein (CCSP) in bronchoalveolar lavage fluid has been associated with chronic lung allograft dysfunction (CLAD) as well as the induction of exosomes and immune responses that lead to CLAD. However, the mechanisms by which CCSP decline contributes to CLAD remain unknown.

METHODS

To define the mechanisms leading to CCSP decline and chronic rejection, we employed two mouse models: 1) chronic rejection after orthotopic single lung transplantation and 2) anti-major histocompatibility complex (MHC) class I-induced obliterative airway disease.

RESULTS

In the chronic rejection mouse model, we detected circulating exosomes with donor MHC (H2b) and lung self-antigens and also development of antibodies to H2b and lung self-antigens and then a decline in CCSP. Furthermore, DBA2 mice that received injections of these exosomes developed antibodies to donor MHC and lung self-antigens. In the chronic rejection mouse model, natural killer (NK) and CD8 T cells were the predominant graft-infiltrating cells on day 14 of rejection followed by exosomes containing NK cell-associated and cytotoxic molecules on day 14 and 28. When NK cells were depleted, exosomes with NK cell-associated and cytotoxic molecules as well as fibrosis decreased.

CONCLUSIONS

Induction of exosomes led to immune responses to donor MHC and lung self-antigens, resulting in CCSP decline, leading to NK cell infiltration and release of exosomes from NK cells. These results suggest a novel role for exosomes derived from NK cells in the pathogenesis of chronic lung allograft rejection.

Cutting Edge: Circulating Exosomes with COVID Spike Protein Are Induced by BNT162b2 (Pfizer-BioNTech) Vaccination prior to Development of Antibodies: A Novel Mechanism for Immune Activation by mRNA Vaccines

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) causes severe acute respiratory syndrome. mRNA vaccines directed at the SARS-CoV-2 spike protein resulted in development of Abs and protective immunity. To determine the mechanism, we analyzed the kinetics of induction of circulating exosomes with SARS-CoV-2 spike protein and Ab following vaccination of healthy individuals. Results demonstrated induction of circulating exosomes expressing spike protein on day 14 after vaccination followed by Abs 14 d after the second dose. Exosomes with spike protein, Abs to SARS-CoV-2 spike, and T cells secreting IFN-γ and TNF-α increased following the booster dose. Transmission electron microscopy of exosomes also demonstrated spike protein Ags on their surface. Exosomes with spike protein and Abs decreased in parallel after four months. These results demonstrate an important role of circulating exosomes with spike protein for effective immunization following mRNA-based vaccination. This is further documented by induction of humoral and cellular immune responses in mice immunized with exosomes carrying spike protein.

Outcomes after lung transplantation in recipients aged 70 years or older

BACKGROUND

The proportion of lung transplant (LTx) recipients older than 70 years is increasing, thus we assessed long-term survival after LTx in this cohort relative to younger counterparts.

PATIENTS AND METHODS

We retrospectively reviewed charts of patients who underwent LTx between 2012 and 2016 at our center and divided patients by age: group A (<65 years), B (65-69 years), and C (≥70 years). Survival statistics were evaluated using the Kaplan-Meier method and Cox regression.

RESULTS

The study included 375 LTx recipients: 221 (58.9%) in group A, 109 (29.1%) in group B, and 45 (12.0%) in group C. Group C was mostly men (37/45 [82.2%]; P = 0.003) and had the highest mean serum creatinine at listing (P = 0.02). Survival at 1, 3, and 5 years after transplant in group A (93.2%, 70.1%, 58.8%) was significantly higher than group B (83.5%, 59.6%, 44.0%; P = 0.005, 0.028, 0.006, log-rank test) and was similar to group C (86.7%, 64.4%, 57.8%), although trended higher at 1 year (P = 0.139, 0.274, 0.489, log-rank test). Groups B and C had comparable survival at all time points.

CONCLUSIONS

Although survival decreased after age 65, long-term survival was comparable between LTx recipients aged 65-69 years and recipients ≥70 years.

Circulating exosomes induced by respiratory viral infections in lung transplant recipients activate cellular stress, innate immune pathways and epithelial to mesenchymal transition

BACKGROUND

Chronic lung transplant rejection occurs in over 50% of lung transplant recipients and mechanism of chronic rejection is unknown. Evaluation of potential mechanism of exosomes from lung transplant recipients diagnosed with respiratory viral infection (RVI) in inducing chronic lung allograft dysfunction (CLAD).

METHOD

Exosomes were isolated from lung transplant recipients followed by DNA and RNA isolation from exosomes. Cell signaling mechanisms were studied by co-culturing exosomes with human epithelial cells. Mice were immunized with exosomes and lung homogenates were studied for immune signaling proteins.

RESULTS

Exosomes from lung transplant recipients with RVI carry nucleic acids which are capable of inducing innate immune signaling, endoplasmic reticulum stress, and epithelial mesenchymal transition.

CONCLUSION

Therefore, we propose that RVI can lead to induction of exosomes that initiate the process leading to CLAD in mice models. These novel findings identified the molecular mechanisms by which RVI increases the risk of CLAD.

Inpatient Lung Transplant Evaluation Is Associated With Increased Risk of Morbidity, Mortality, and Cost of Care After Transplant

Lung transplantation is an important option for patients with end-stage lung disease. Many of these patients deteriorate rapidly and require inpatient care at the time of the transplant evaluation.

RESEARCH QUESTION

How does the setting of lung transplant evaluation relate to perioperative outcomes, short-term postoperative outcomes, and healthcare costs accrued after transplant?

DESIGN

We reviewed the records of patients who underwent primary, bilateral lung transplantation at our center between January 1, 2014 and May 31, 2016. Patient evaluation setting was categorized as inpatient, outpatient, or combined. Demographics, clinical characteristics, and cost of care were assessed.

RESULTS

The study included 207 patients: 40 (19.3%) evaluated as inpatients, 146 (70.5%) as outpatients, and 21 (10.1%) as combined. Inpatients had the highest mean lung allocation scores (71.2 vs 49.7 [combined] and 40.8 [outpatient]; P < 0.001), lowest functional status at listing (P < 0.001), highest number of blood products used during surgery (P < 0.001), highest incidence of re-exploration for bleeding (P = 0.006), and longest posttransplant hospital stays (median, 35 vs 15 days [combined] and 12 days [outpatient]; P < 0.001). One-year survival trended lower for inpatients (log-rank, P = 0.056). Inpatient evaluations had the highest total, variable, and fixed costs of posttransplant care (P < 0.001).

CONCLUSION

Inpatient lung transplant evaluation was associated with longer hospital stays, higher perioperative morbidity, and lower 1-year survival. Partial or complete inpatient evaluation was associated with a higher cost of care posttransplant.

Bilateral Lung Transplant for a Connective Tissue Disorder: Esophageal Motility and 3-year Survival

Connective tissue disorders (CTDs) are associated with esophageal dysmotility and gastroesophageal reflux disease, which may diminish survival after lung transplantation (LTx). We studied LTx outcomes in patients with a CTD stratified by esophageal motility. We identified patients who underwent bilateral LTx from 2012 to 2017. Patients with a CTD were classified by pre-LTx diagnosis: absent esophageal motility (AEM), ineffective esophageal motility (IEM), or preserved esophageal motility (PEM). The primary endpoint was 3-year survival. Sub-analysis compared survival between the AEM group and a propensity-matched (lung allocation score), non-CTD control group. Kaplan-Meier method and log-rank test were used. In total, 495 patients underwent LTx; 33 (6.7%) had a CTD. Median (IQR) age was 62 years (55.5-67.0); 24 (72.7%) were women. Survival trended lower for recipients with a CTD than without a CTD at 1-year (84.8% vs 91.8%; p = 0.2) and 3-years (66.7% vs 73.5%; p = 0.5). Within the CTD cohort, 1- and 3-year survival was significantly higher in the PEM (100%, 87.5%) and IEM (100%, 85.7%) groups than in the AEM group (50%, 20%; p < 0.001). The AEM group had significantly lower survival at 1-year (50% vs 92.5%) and 3-years (20% vs 65%) than a lung allocation score-matched cohort of patients without a CTD. LTx recipients with a CTD and AEM had significantly lower survival than those with PEM or IEM as well as significantly lower survival than that of a propensity-matched cohort of patients without a CTD. Patients with a CTD and AEM should be considered for LTx with extreme caution and counseled appropriately.

Esophagogastric Junction Outflow Obstruction: Are We Missing Anything?

GOALS

The authors aimed to compare preperistaltic distal esophageal pressure in patients with esophagogastric junction outflow obstruction (EGJOO) with and without reported dysphagia.

BACKGROUND

Manometric EGJOO is characterized by elevated integral relaxation pressure (>15 mm Hg) without achalasia. The nomenclature inherently implies that it should be associated with impaired food bolus transit and should theoretically present clinically as dysphagia.

STUDY

The authors queried an esophageal functional test database to identify patients diagnosed with EGJOO. They excluded patients who presented with ≥2 swallows with abnormal (ie, weak, failed or hypercontractile) esophageal body motility. To elucidate differences in manometric findings, the authors formed 2 cohorts of patients on the basis of a standard esophageal symptom questionnaire: those without dysphagia and those with severe or very severe dysphagia. All studies were reanalyzed to determine the distal esophageal pressure before each peristaltic wave (ie, the preperistaltic pressure) for individual swallows. The Mann-Whitney U test was used to compare categorical variables between groups. The level of significance was set to P<0.05.

RESULTS

In total, 149 patients were diagnosed with EGJOO during the study period. Of these, 42 patients with ≥9 (out of 10) peristalsis (20 without dysphagia and 22 with severe/very severe dysphagia) formed the study cohorts. Patients with severe dysphagia had significantly higher median preperistaltic pressures in the distal esophagus. Preperistaltic pressure measurements showed better sensitivity and specificity for dysphagia than integral relaxation pressure.

CONCLUSIONS

Elevated preperistaltic pressure is noted in symptomatic EGJOO patients. Inclusion of preperistaltic pressure in the diagnostic criteria for EGJOO may increase the clinical relevance of manometric classification.

Clinical spectrum and presentation of patients with absent contractility

Background

Primary absent contractility is an uncommon finding on high-resolution manometry (HRM). The goal of this study was to describe the clinical spectrum and presentation of patients with primary absent contractility.

Methods

We queried a prospectively maintained esophageal testing registry to identify patients with absent contractility who presented between August 2016 and September 2018. Patients with poor quality studies and patients with insufficient clinical records as well as those with a history of previous foregut surgery or esophagram consistent with achalasia were excluded.

Results

A total of 2068 patients underwent HRM during the study period. Of these, 66 patients (3.2%) met the inclusion criteria and formed the study cohort; 52 patients in the cohort had an upper gastrointestinal contrast study, 50 had endoscopy, and 51 completed a foregut symptom questionnaire. Thirty-eight patients (57.6%) were women. The mean age was 56.6±13.86 years, and the mean body mass index was 26.37±5.7 kg/m². Almost half of the patients (29/66, 43.9%) were undergoing lung transplant evaluation, and 22 patients (37.3%) had a history of autoimmune immune-mediated or myopathic diseases. On the symptom questionnaire, 42 of 51 patients (82.3%) reported heartburn, 24 of 51 (47.1%) reported dysphagia, and 23 of 51 patients (45.1%) reported both. On ambulatory pH monitoring, 23 of 37 patients (62.2%) had pathological esophageal acid exposure (acid exposure time >6%).

Conclusions

Absent contractility on HRM is uncommon and is frequently associated with connective tissue, myopathic or autoimmune disorders. The usual clinical presentation is reflux, dysphagia or both.

An update on current treatment strategies for managing bronchiolitis obliterans syndrome after lung transplantation

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS), a subtype of chronic lung allograft dysfunction, is quite common, with up to half of all lung recipients developing BOS within 5 years of transplantation. Preventive efforts are aimed at alleviating known risk factors of BOS development, while the primary goal of treatment is to delay the irreversible, fibrotic airway changes, and progressive loss of lung function.

AREAS COVERED

This narrative review will briefly discuss the updated definition, clinical presentation, pathogenesis, risk factors, and survival after BOS while paying particular attention to the salient evidence for optimal preventive strategies and treatments based on investigations in the modern era.

EXPERT OPINION

Future translational research focused on further characterizing the complex interplay between immune and nonimmune mechanisms mediating chronic lung rejection is the first step toward mitigating risk of allograft injury, improving early disease detection with noninvasive biomarkers, and ultimately, developing an effective, targeted therapy that can extend the life of the lung allograft.

A Collective Review of Gore Bio-A Absorbable Synthetic Mesh in Cruroplasty Reinforcement

Background: Laparoscopic repair of hiatal hernia (HH) is associated with a considerable failure rate. Compared to suture repair alone, mesh-reinforced cruroplasty may be associated with fewer short-term recurrences, yet its use remains controversial. The aim of this study was to analyze the current literature assessing the use of Bio-A absorbable synthetic mesh in the reinforcement of primary crural closure after laparoscopic HH repair. Methods: A systematic review of primary literature in the MEDLINE and PubMed databases was conducted. We searched for investigations reporting patient outcomes in laparoscopic HH repair with onlay Gore Bio-A tissue reinforcement (W. L. Gore & Associates, Inc.) published between January 2008 and December 2019. The primary outcome was anatomical recurrence rate. Secondary outcomes were complication rate, symptomatic outcomes, and mortality. Results: Eight studies met inclusion criteria. There were two prospective and six retrospective cohort studies. In the included studies, laparoscopic HH repair was performed with Bio-A absorbable synthetic mesh in 734 patients. The anatomical recurrence data were extracted across all studies, and an objective recurrence was identified in 21/280 (7.5%) patients. There was only 1 (0.17%) mesh-related complication in the included studies. Conclusions: The use of Bio-A absorbable synthetic mesh in the repair of HHs may be promising, as it offers low rates of anatomical recurrence and mesh-related complications, but more data are still necessary to validate these findings. This collective review of literature is a basis for future randomized controlled trials to identify the most effective and safe mesh in the long term.

The role of miRNA-155 in the immunopathogenesis of obliterative airway disease in mice induced by circulating exosomes from human lung transplant recipients with chronic lung allograft dysfunction

Human lung transplant recipients undergoing rejection induce circulatory exosomes with lung self-antigens (SAgs), K-alpha 1 Tubulin and Collagen V, and immunization of C57BL/6 mice with exosomes induced obliterative airway disease (HEI-OAD). We analyzed whether exosomes with SAgs induced immunity in microRNA-155 knockout mice (miR-155KO), as microRNA-155 is an immune regulator. C57BL/6 and miR-155KO were immunized with exosomes from stable or chronic rejection (bronchiolitis obliterans syndrome (BOS) and on day 30, induction of exosomes, antibodies (Abs) to SAgs and cellular immunity were determined. C57BL/6 immunized with exosomes from BOS developed OAD. These immunized animals also developed Abs to SAgs and increased frequency of SAg-specific IFNγ and IL17- producing cells. In contrast, Abs to SAgs did not develop in miR-155KO and there was reduction in frequency of cells producing IL10. Upregulation of suppressor of cytokine signaling for lung inflammation was also noted resulting in abrogation of induction of exosomes with SAgs OAD.

Circulating exosomes with lung self-antigens as a biomarker for chronic lung allograft dysfunction: A retrospective analysis

BACKGROUND

Exosomes isolated from plasma of lung transplant recipients (LTxRs) with bronchiolitis obliterans syndrome (BOS) contain human leukocyte antigens and lung self-antigens (SAgs), K-alpha 1 tubulin (Kα1T) and collagen type V (Col-V). The aim was to determine the use of circulating exosomes with lung SAgs as a biomarker for BOS.

METHODS

Circulating exosomes were isolated retrospectively from plasma from LTxRs at diagnosis of BOS and at 6 and 12 months before the diagnosis (n = 41) and from stable time-matched controls (n = 30) at 2 transplant centers by ultracentrifugation. Exosomes were validated using Nanosight, and lung SAgs (Kα1T and Col-V) were detected by immunoblot and semiquantitated using ImageJ software.

RESULTS

Circulating exosomes from BOS and stable LTxRs demonstrated 61- to 181-nm vesicles with markers Alix and CD9. Exosomes from LTxRs with BOS (n = 21) showed increased levels of lung SAgs compared with stable (n = 10). A validation study using 2 separate cohorts of LTxRs with BOS and stable time-matched controls from 2 centers also demonstrated significantly increased lung SAgs-containing exosomes at 6 and 12 months before BOS.

CONCLUSIONS

Circulating exosomes isolated from LTxRs with BOS demonstrated increased levels of lung SAgs (Kα1T and Col-V) 12 months before the diagnosis (100% specificity and 90% sensitivity), indicating that circulating exosomes with lung SAgs can be used as a non-invasive biomarker for identifying LTxRs at risk for BOS.

Management and Outcomes of Diverticulitis After Lung Transplantation

INTRODUCTION

Most lung transplant patients are older than 50 years. Complications from colonic diverticula are not uncommon, especially with chronic immunosuppression. However, limited data exist regarding the optimal management of these patients. We sought to investigate the incidence, risk factors, and outcomes of diverticulitis after lung transplant.

METHODS

We conducted a retrospective study to review patients undergoing lung transplant between 2007 and 2016 with posttransplant acute colonic diverticulitis. Patients were grouped based on medical or surgical management.

RESULTS

Of 512 transplant recipients, 17 (3.32%) developed 26 episodes of diverticulitis over a median follow-up of 39 months. Nine patients had documented diverticulosis on pretransplant colonoscopy. These patients had a higher incidence of surgical intervention for diverticulitis, were more likely to have recurrent diverticulitis, and had longer lengths of stay than patients without pretransplant diverticulosis. Six (35.3%) of 17 patients required surgery (ie, Hartmann procedure; 4 during the initial episode and 2 during their third and fourth episodes); 11 patients (64.7%) were managed with antibiotics alone. Patients in the surgical group presented earlier posttransplant (P = .004) and were on higher doses of tacrolimus (P = .03). Six (46.1%) of 13 patients with medically managed first episodes of diverticulitis experienced recurrence. No recurrence occurred after surgical management. No deaths were attributable to diverticulitis in either group.

CONCLUSIONS

Patients with pretransplant diverticulosis experienced earlier, more complicated episodes of diverticulitis posttransplant than patients without. Surgical patients received higher doses of tacrolimus and presented earlier than medical patients. Uncomplicated diverticulitis in posttransplant patients can be managed medically, even in the case of recurrent, uncomplicated disease.

Global Proteomics Analysis of Circulating Extracellular Vesicles Isolated from Lung Transplant Recipients

Lung transplant recipients (LTxRs) with acute rejection (AR) and chronic rejection (bronchiolitis obliterans syndrome [BOS]) induce circulating exosomes known to contain donor human leukocyte antigens and lung-associated self-antigens. Here, we sought to identify proteomic signatures in circulating extracellular vesicles (EVs) that differentiate LTxRs in 4 groups: stable, AR, BOS, or respiratory viral infection (RVI). EVs were isolated from plasma from patients in each group via ultracentrifugation. EV protein cargoes were prepared for shotgun proteomics using liquid chromatography-tandem mass spectrometry. We identified 2 unique proteins for AR, 4 for RVI, 24 for BOS, and 8 for stable LTxRs. Differential analysis of AR, BOS, RVI, and stable proteins identified significantly deregulated proteins (p < 0.05, log₂(fold change) > ±1) in each condition (31, 2, and 2, respectively). EVs from LTxRs with AR contained proteins involved in immunoglobulin, complement regulation, coagulation, and innate and adaptive immune response pathways. EVs from LTxRs with BOS revealed enriched immunoglobulin receptors and a carboxypeptidase N catalytic chain. EVs from LTxRs with RVI had an enriched macrophage-stimulating factor. We found unique signatures in LTxRs with AR, BOS, and RVI, highlighting complex immune mechanisms underlying lung allograft rejection. Proteomic signatures in LTxRs' circulating EVs provided insights into immunological mechanisms of graft rejection and RVI.

Simple Manometric Index for Comprehensive Esophagogastric Junction Barrier Competency Against Gastroesophageal Reflux

BACKGROUND

The esophagogastric junction (EGJ) is an anatomic and physiologic barrier against gastroesophageal reflux. Comprehensive evaluation of EGJ barrier parameters using high-resolution manometry in patients with GERD has not been well established. We propose a simple index for comprehensive EGJ antireflux competency.

STUDY DESIGN

Patients who underwent high-resolution manometry and 24-hour pH monitoring between January 2017 and September 2018 were included. Of these, patients with normal esophageal motility were selected. EGJ antireflux competency was assessed based on the following 3 categories: anatomic configuration of the EGJ complex (ie EGJ morphology), backflow-preventive pressure on the lower esophageal sphincter (LES) (ie LES pressure integral), and backflow-promotive pressure across the LES (ie thoracoabdominal pressure gradient). Each category was scored on a scale of 0 to 2, applying clinically meaningful divisions, and a cumulative score was calculated (EGJ index: 0 to 6 points). DeMeester score > 14.72 indicated GERD.

RESULTS

In total, 259 patients met study criteria. Of these, GERD was noted in 109 patients (42.1%). The pH parameters were gradually exacerbated, depending on the EGJ index. Good correlations were seen between EGJ index and previously proposed parameters for EGJ disruption, including LES length, LES pressure, and LES pressure integral (area under the curve > 0.9 [excellent validation]). No patient had GERD if the EGJ index score was 0. However, GERD was seen in as high as 85.7% of patients with the highest score of 6.

CONCLUSIONS

EGJ disruption severity was clearly graded based on a simple scoring method, which can improve evaluation and development of clinical strategies for GERD.

Clinical Symptom Presentation of Hypercontractile Peristalsis in the Era of High-Resolution Manometry: A Single-Center Experience

BACKGROUND

Hypercontractile motility of the esophagus is occasionally noted on high-resolution manometry (HRM), but its clinical correlations are unclear. We compared symptom severity and clinical presentation of patients with hypercontractile motility of the esophagus.

METHODS

This was a retrospective cohort study. We queried a prospectively maintained database for patients who underwent esophageal function testing from October 1, 2016, to October 30, 2018. We included patients with jackhammer esophagus (JE; ≥2 swallows with distal contractile integral [DCI] ≥8,000 mm Hg∙cm∙s), nutcracker esophagus (NE; mean DCI 5,000-8,000 mm Hg∙cm∙s without meeting JE criteria), or esophagogastric junction outflow obstruction ([EGJOO]: abnormal median integrated relaxation pressure (>15 mm Hg) without meeting achalasia criteria, with JE [EGJOO-h], or normal motility [EGJOO-n]). HRM, endoscopy, barium esophagram, ambulatory pH studies, and symptom questionnaires were reevaluated for further analysis. Clinical parameters were analyzed using Spearman Rho correlation. Categorical variables were assessed with Fisher exact or chi-square test.

RESULTS

Altogether, 85 patients met inclusion criteria. They were divided into 4 subgroups: 28 with JE, 18 with NE, 15 with EGJOO-h, and 24 with EGJOO-n. Patients with EGJOO-h were the most symptomatic overall. No correlation was seen between symptoms and mean DCI (p ≥ 0.05 all groups) or number of hypercontractile swallows (≥8,000 mm Hg∙cm∙s, p ≥ 0.05). A significant correlation was noted between dysphagia and lower esophageal sphincter pressure (LESP) and LESP integral (p ≤ 0.05).

CONCLUSION

The number of hypercontractile swallows and mean DCI were not associated with patient-reported symptoms. Elevated LESP may be a more relevant contributor to dysphagia.

Respiratory viral infection in lung transplantation induces exosomes that trigger chronic rejection

BACKGROUND

Respiratory viral infections can increase the risk of chronic lung allograft dysfunction after lung transplantation, but the mechanisms are unknown. In this study, we determined whether symptomatic respiratory viral infections after lung transplantation induce circulating exosomes that contain lung-associated self-antigens and assessed whether these exosomes activate immune responses to self-antigens.

METHODS

Serum samples were collected from lung transplant recipients with symptomatic lower- and upper-tract respiratory viral infections and from non-symptomatic stable recipients. Exosomes were isolated via ultracentrifugation; purity was determined using sucrose cushion; and presence of lung self-antigens, 20S proteasome, and viral antigens for rhinovirus, coronavirus, and respiratory syncytial virus were determined using immunoblot. Mice were immunized with circulating exosomes from each group and resulting differential immune responses and lung histology were analyzed.

RESULTS

Exosomes containing self-antigens, 20S proteasome, and viral antigens were detected at significantly higher levels (p < 0.05) in serum of recipients with symptomatic respiratory viral infections (n = 35) as compared with stable controls (n = 32). Mice immunized with exosomes from recipients with respiratory viral infections developed immune responses to self-antigens, fibrosis, small airway occlusion, and significant cellular infiltration; mice immunized with exosomes from controls did not (p < 0.05).

CONCLUSIONS

Circulating exosomes isolated from lung transplant recipients diagnosed with respiratory viral infections contained lung self-antigens, viral antigens, and 20S proteasome and elicited immune responses to lung self-antigens that resulted in development of chronic lung allograft dysfunction in immunized mice.

Factors associated with skin cancer in lung transplant recipients: A single-center experience

BACKGROUND

Skin cancer is common after solid organ transplantation, but few have investigated it after lung transplant (LTx).

OBJECTIVE

We assessed incidence and predictors of non-melanoma skin cancer (NMSC) post-LTx.

METHODS

We studied patients who underwent LTx at our center from 2012 to 2015.

RESULTS

Of 287 patients, mean age was 59.6 ± 11 years, 170 (59.2%) were men, and 231 (80.5%) were white. Seventy-six (26.5%) developed NMSC over a median follow-up of 32 months (IQR, 23-45). Of those with NMSC, 37% developed subsequent skin cancer of the same type. Independent predictors of decreased odds of NMSC and squamous cell carcinoma (SCC) were non-white race (P = .002; P = .003) and body mass index >30 kg/m² compared with underweight patients (P = .001, P = .009). Patients with skin cancer pre-LTx had higher risk of post-LTx skin cancer (P = .02). Voriconazole use ≥100 days was associated with increased risk of SCC (P = .03), but not increased risk of basal cell carcinoma. Out of 76, 4 (5.3%) died from skin cancer.

LIMITATIONS

Retrospective, single-center study.

CONCLUSION

Squamous cell carcinoma risk post-LTx may increase with prolonged voriconazole use in white patients with pre-LTx history of skin cancer, whereas excess body weight may be protective from NMSC. Regular pre- and post-LTx skin cancer screenings and guidelines are warranted.