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Background Right ventricular (RV) maladaptation to elevated pulmonary afterload is the primary determinant of outcomes in pulmonary artery (PA) hypertension; however, the pathobiological mechanisms underlying RV decompensation remain poorly understood. Methods We performed global untargeted metabolomics on plasma from 55 patients who underwent gold‐standard RV‐PA coupling measurements using multibeat pressure volume loop assessment in a single‐center cohort and from 1027 patients with coupling surrogate measurements in a larger multicenter cohort, the PVDOMICS (Pulmonary Vascular Disease Phenomics) study. Age and sex‐adjusted linear regression was performed to identify associations between metabolites and coupling metrics. Additionally, we performed a metabolic flux analysis using gene expression data from RV tissue in an independent cohort of 32 patients. Partial least squares–discriminant analysis was used to identify metabolites and reactions characteristic of the decompensated RV. Results RV‐PA coupling was negatively associated with tricarboxylic acid (TCA) cycle intermediate levels. Specifically, plasma α‐ketoglutarate and fumarate were significantly associated with all coupling metrics in both cohorts. Metabolic flux analysis indicated that decompensated RVs exhibited aberrant TCA cycle activity, including reduced acetyl coenzyme A entry and increased lactate elimination, suggesting a shift from the TCA cycle toward glycolysis at the RV tissue level. Conclusions We identify an association between circulating TCA cycle intermediate levels and RV‐PA uncoupling in 2 independent cohorts, and dysregulated TCA cycle metabolism in decompensated PA hypertension RVs, suggesting that aberrant TCA cycle metabolism could represent a hallmark of RV maladaptation in PA hypertension. Further study of this pathway is warranted to develop novel biomarkers of RV function or RV‐targeted therapies.

Transbronchial cryobiopsies (CB) are increasingly replacing surgical biopsies (video-assisted thoracoscopic/VATS biopsies) for diagnosing diffuse parenchymal lung disease (interstitial lung disease, ILD), but there is very little guidance for pathologists on CB interpretation. Here we propose a fairly simple approach. First, if the diagnosis can be made on a traditional forceps biopsy, it can be made on a cryobiopsy. Many diseases with specific features will fall into this category (eg, sarcoidosis or Langerhans cell histiocytosis). More problematic are patterns such as usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP), in which low-power architecture is the key to diagnosis. In this circumstance, an adequate sample is crucial to look for features such as fibroblast foci, because a combination of fibroblast foci plus any patchy old fibrosis, fibrotic architectural remodeling, or honeycombing, allows a diagnosis of a UIP pattern. However, in most instances, CB will not separate the UIP patterns seen in idiopathic pulmonary fibrosis, fibrotic hypersensitivity pneumonitis, or connective tissue disease-interstitial lung disease (CTD-ILD), although giant cells/granulomas (uncommon findings) in this setting favor fibrotic hypersensitivity pneumonitis. Fibroblast foci can be difficult to differentiate from organizing pneumonia (OP), but granulation tissue plugs clearly in airspaces favor OP. Absent fibroblast foci, patchy old fibrosis, architectural distortion, and honeycombing by themselves do not allow a specific diagnosis. NSIP in CB microscopically looks like NSIP in VATS biopsies, and the presence of an NSIP or an NSIP+OP pattern is typical of CTD-ILD. All the above diagnoses require correlation with clinical and radiologic findings.

Abstract Non-tubercular mycobacteria (NTM) present a serious challenge in managing lung transplant candidates and recipients. Pretransplant NTM isolation has been associated with post-transplant NTM infection and significantly increased mortality risk. Strategies for managing pre-transplant NTM isolation vary widely in clinical practice. We present a 35-year-old lung transplant candidate from a tuberculosis-endemic country with severe pulmonary hypertension and Eisenmenger Syndrome due to unrepaired atrial septal defect, who underwent bilateral lung transplantation. Two years prior to transplant, she was successfully treated for pulmonary tuberculosis with six months of an unknown regimen in her home country. After moving to the U.S., she received M. tuberculosis (MTB) clearance from her state tuberculosis board, with three negative sputum samples six months prior to transplant. During her transplant evaluation, multi-drug-resistant M. fortuitum complex was isolated from one mycobacterial sputum culture. There was no clinical or radiographic evidence of active lung infection, and no targeted therapies were added. Standard peri-transplant antibiotics (vancomycin, cefepime, and caspofungin) were given. The patient received basilixamab for induction immunosuppression, and tacrolimus, mycophenolate mofetil, and prednisone for maintenance immunosuppression. Explant pathology showed necrotizing granuloma in the right upper lobe with acid-fast bacilli (AFB). The differential diagnosis included non-viable MTB, viable MTB despite prior clearance, or M. fortuitum. Three bronchoscopy washings were obtained in the first week post-transplant and returned negative for MTB by PCR, AFB stain, and culture. In collaboration with the Mycobacteriology laboratory, broad-range PCR testing was performed on the formalin-fixed paraffin-embedded samples from the explanted right lung, which was positive for MTB complex DNA. In total, the patient completed six sputum samples within the year pre-transplant and six respiratory samples within a month post-transplant, all of which returned negative for MTB by PCR, AFB stain, and culture. Blood flow cytometric (FC) immunoprofiling with mycobacterial antigens and controls was conducted (Escalante et al. 2015). The patient's FC antigen-specific activated T-cell profiling was consistent with a reduced risk of latent TB infection (FC CD4+ CD25+CD134+ T-cells (RD1-peptides-nil) = 0.19%). T-cell reactivity to MTB300 and PPD antigens suggested prior MTB, NTM, and/or BCG vaccination exposures. She progressed well without any preventive therapy for LTBI. FC immunoprofiling one year after transplantation showed similar results. She continues to have good pulmonary function and quality of life in her second-year post-transplant without evidence of NTM or MTB infection. Escalante P, et al. Combinatorial Immunoprofiling in Latent Tuberculosis Infection. Am J Respir Crit Care Med. 2015;192(5):605-17. PMCID: PMC4595688.

Abstract Rationale: Tandem exposure to cannabinoids and nicotine during pregnancy poses significant risks to fetal development and health including low birth weight, preterm birth, and perinatal death. However, the effect of co-exposure with the most prominent cannabinoids found in Cannabis sativa (Trans-Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD)) alongside nicotine on fetal lung development is not well understood. This study aims to investigate the combinatorial impact of CBD, THC, and nicotine, on human lung development through investigating cellular senescence and the potential role of senolytics in alleviating these effects.Methods: Human fetal lung explants from 10 to 16 weeks gestation were cultured on air-liquid interface and treated with various concentrations of nicotine (1µM), CBD, and THC (5µM, or 2.5µM each when used in combination), for 72 hours. To assess the effect of senolytics, the explants were also treated for 48 hours with a combination of CBD, THC, and nicotine. Subsequently, senolytics, Dasatinib (D, 250nM) and Quercetin (Q, 375nM), were added or not for an additional 24 hours. After the 72-hour treatment, explants were collected and either fixed for immunofluorescence staining (IF) analyses or used for RNA extraction and quantitative reverse transcription PCR (qRT-PCR). Additionally, the supernatants were used to evaluate the expression of the senescence-associated secretory phenotype (SASP), conducted by Eve Technologies Corporation-Canada. This study used Luminex xMAP technology for multiplexed quantification of 96 Human cytokines, chemokines, and growth factors.Results: Our results demonstrated that co-exposure to CBD, THC, and nicotine increases the expression of the senescence markers CDKN1A (0.1163±0.02384, p=0.0094, n=8) and CDKN2A (0.005793±0.002157, p=0.0516, n=8) encoding P21 and P16 respectively. Moreover, the IF staining showed increased expression of the DNA damage marker ɣH2A.X following treatment with CBD+THC+nicotine (7.375±2.154% vs 2.245±0.8329%, p=0.0604, n=6). Furthermore, the lung explants treated with cannabinoids and nicotine released cytokines and chemokines involved in immune responses and inflammation among others IL-6, IL-8, M-CSF, MCP-3, MIP-1β, TNFα, MIP-3β, and TSLP (p<0.05). The addition of D+Q reduced SASP secretion and showed a decreasing trend in expression of the senescence genes CDKN1A and CDKN2A compared to the triple treatment.Conclusion: Taken together, our results showed that the combinatorial exposure to CBD, THC, and nicotine increases senescence, DNA damage, and the senescence-associated secretory phenotypes (SASP) secretion. The use of senolytics (D+Q) may prove to be a promising therapeutic option, alleviating several of the negative effects induced by the different substances.

Abstract RATIONALE: Susceptibility to severe COVID-19 and long COVID may be influenced by pre-existing lung structure. ECG-gated, non-contrast cardiac CT scans, originally acquired for assessing coronary artery calcium, are available in multiple longitudinal cohort studies and have been previously validated against lung CT scans for densitometry; however, protocol variation across cohorts may hinder direct comparison. To address this, we developed a quality control (QC) rubric to grade cardiac CT scans for standardized quantitative lung measures across cohorts. METHODS: C4R assessed SARS-CoV-2 infection and outcomes in 14 NHLBI cohorts, of which 10 (six community-based and four longitudinal case-control studies) included CT scans (12,459 participants with lung and 13,752 with cardiac CTs). Logic rules were applied to categorize scans (Table): Grade “A-B” scans had 2-3.5mm slice thickness, at least 20 axial slices, no lung cropping in axial view and lung and airway volumes greater than the cohort-specific 1st percentile. “C-D” scans had one lung obscured by cropping around the heart, so quantitative measures were restricted to the lung in complete view. “F-H” scans were deemed unusable, suffering from low slice count (<20), severe image cropping, low lung or airway volumes (< 1st%ile). Visual inspection was performed on a sample from each category to ensure accuracy. Percent of lung voxels in low attenuation areas < -950 HU (LAA950), high attenuation areas (-600 to -250 HU, HAA) and 15th percentile HU value (perc15) were measured. Within-participant variability was quantified using the intraclass correlation coefficient (ICC). RESULTS: We performed QC on cardiac CT scans from an initial sample of 6,275 participants from three C4R cohorts (ARIC, CARDIA, MASALA), imaged with GE or Siemens scanners. Of these, 5,125 (81.7%) were graded “A-B”, 496 (7.9%) were “C-D” and 654 (10.4%) were “F-H”. The percentage of “F-H” scans varied widely across cohorts [<1% to 26%] due to image cropping. Among the 5,621 cardiac CT scans graded A-D, the mean±SD for LAA950, HAA and perc15 respectively were 1.1±2.1%, 7.2±4.7% and -887±33 HU. Repeated imaging was available for 107 participants (time interval 5.1±0.7y). For paired scans in grades A-B (n=101/107), the within-participant correlation for LAA950, HAA and perc15 were 0.91, 0.38 and 0.74 respectively. CONCLUSION: Initial application of QC to cardiac CT scans identified scans with high reproducibility, with the aim to provide valid quantitative lung metrics on over 20,000 highly characterized participants in C4R.

Abstract Introduction: Hemolytic uremic syndrome (HUS) is especially uncommon in adults and can manifest as devasting complications including severe acute kidney injury (AKI) and microangiopathic hemolytic anemia (MAHA). Transfusion-related acute lung injury (TRALI) is a rare complication of blood product transfusion that is characterized by the rapid development of noncardiogenic pulmonary edema. We present a rare case of HUS complicated by TRALI requiring mechanical ventilation. Case Description: A 41-year-old female farmer, who occasionally drank raw cow's milk, was admitted with abdominal pain and distension, bloody diarrhea, poor appetite, decreased urine output and fatigue. She was found to have MAHA and stage 3 AKI. Imaging demonstrated pancolitis and workup revealed Shiga toxin-producing E. coli, O157:H7 serotype which was consistent with a diagnosis of HUS. Tests for DIC, TTP and atypical HUS were negative. She was not a candidate for dialysis, plasma exchange or eculizumab. With supportive measures including 3 units of packed red blood cell (pRBC), her symptoms, renal function, and bicytopenia improved and she was discharged. Two days post-discharge, she presented to the ED for unilateral vision changes, left hemiparesis, and lower extremity tremor. After negative neurological evaluation, this was attributed to encephalopathy secondary to HUS. She received 1 unit of pRBCs for a hemoglobin of 6.8. Within 3 hours of transfusion, she developed acute respiratory distress requiring intubation and ICU transfer. CT chest angiogram was negative for pulmonary embolism but demonstrated diffuse bilateral lower lobe dependent consolidations concerning for TRALI (Figure 1). After diuresis, she was able to be extubated within 48 hours with return to her respiratory and neurologic baselines soon after. Discussion: The pathophysiology of TRALI involves neutrophil sequestration and priming in the pulmonary vasculature with subsequent neutrophil activation by donor blood product factors where active infection is a known risk factor. Active HUS likely contributed to neutrophil priming through endothelial damage and systemic inflammation, predisposing this patient to TRALI. There are few reports of similar cases in the literature. TRALI can be subdivided into type I and type II; type I has no risk factors for acute respiratory distress syndrome (ARDS) while type II does. TRALI must also be distinguished from ARDS and transfusion-associated circulatory overload; these distinctions are predominantly made based on timing of respiratory symptom onset. This case highlights the importance of keeping TRALI in the differential for all patients with active or recent infection, including HUS, who develop acute-onset respiratory decompensation after transfusion.

Abstract Introduction: We present a case of constrictive bronchiolitis with paraneoplastic autoimmune multi-organ syndrome (PAMS) treated with lung transplantation. To our knowledge, this is the first reported case of PAMS with constrictive bronchiolitis managed with this approach. Presentation: A 45-year-old woman presented with 3 months of dyspnea. PFTs showed severe airflow obstruction with air trapping and no immediate bronchodilator response. [FEV1 0.94L (z: -3.9), FVC 2.98L (z: -0.515), TLC 4.89L (z: 1.0), RV 1.70L (z: 2.4) and DLCO 22 ml/min/mmhg (z: 0.58)] CT chest with expiratory views showed air trapping in the left upper lobe and ground glass opacities, consistent with constrictive bronchiolitis. 6 months prior, she was diagnosed with abdominal grade 1 follicular lymphoma, treated with Bendamustine and Rituximab. One month into treatment, she developed a lichenoid rash involving the oro-gential mucosa and erythematous papular skin eruptions. Her eruptions and constrictive bronchiolitis were consistent with PAMS with pulmonary involvement. The rash improved with oral steroids and topical therapies, but her pulmonary symptoms did not. The likelihood of progression was low, so lymphoma was not a contraindication for lung transplantation. To ensure complete metabolic remission, she was further treated with R-CHOP and maintained on Rituximab. During transplant evaluation, FEV1 was 30% with NYHA class II, Karnofsky score 60 and she required 4L oxygen. She grew mycobacterium abscessus subspecies abscessus on 3 different sets of induced sputum. Secondary to radiographic findings consistent with NTM-PD (bronchial wall thickening and mucoid impaction) and pending lung transplant, she was treated with omadacycline, tedizolid, amikacin and clofazimine until sputum culture negativity (3-months). She underwent lung transplantation and received pre-operative Mycophenolate and Methylprednisolone without induction immunosuppression. Post-operatively she was started on Tacrolimus, Mycophenolate Mofetil and Prednisone. M. Abscessus therapy continued for 2 months post-transplant. At 6 months post-transplant, she is well, and PFTs are improving without evidence of organ rejection, lymphoma recurrence, or M. abscessus infection. Discussion: Pulmonary involvement in PAMS is associated with high mortality and is not reversed by treatment of the neoplasm, due to non-reversible destruction of small airways. The only disease modifying therapy is lung transplant. Her lymphoma recurrence risk was very low after 2 years of remission following initial treatment, and as her lymphoma was not associated with immunosuppression, post-transplant immunosuppression likely does not increase risk of recurrence. Additionally, while mycobacterium abscessus poses significant risks, intensive treatment in the peri-transplant period can help allow for safe transplantation.

Abstract Rationale Non-cystic fibrosis bronchiectasis (hereafter bronchiectasis) is a chronic and progressive respiratory disease. Neutrophilic inflammation plays a key role in the pathophysiology of bronchiectasis. Neutrophil serine proteases (NSPs), especially neutrophil elastase, have been associated with disease progression and poorer clinical outcomes. Brensocatib, an oral, selective, competitive, and reversible inhibitor of dipeptidyl peptidase 1, prevents activation of NSPs. In the phase 3, randomized, double-blind ASPEN trial (NCT04594369), treatment with once-daily brensocatib 10- or 25-mg significantly reduced the annualized rate of adjudicated pulmonary exacerbations over 52 weeks vs placebo; brensocatib 25-mg also significantly reduced lung function decline and improved patient-reported symptoms. Here, we further evaluate the impact of brensocatib on lung function in patients with bronchiectasis. Methods ASPEN enrolled patients with bronchiectasis and a history of pulmonary exacerbations in the 12 months prior to screening (adults [18-85 years], ≥2; adolescents [12-<18 years], ≥1). Patients were randomized to receive once-daily brensocatib (10- or 25-mg) or matching placebo for 52 weeks (adults, 1:1:1; adolescents, 2:2:1). Post-hoc analyses were conducted to evaluate the extent of lung function response to treatment, as measured by change from baseline in post-bronchodilator (BD) forced expiratory volume in 1 second (FEV1) over the 52-week treatment period in patients who did vs did not have ≥1 on-study pulmonary exacerbation, and the level of change in post-BD FEV1 and forced vital capacity (FVC) at week 52. Results A total of 583 patients received brensocatib 10-mg, 575 received brensocatib 25-mg, and 563 received placebo. Overall, a greater decline in FEV1 was observed among patients with ≥1 on-study pulmonary exacerbation vs those without. Treatment with brensocatib 10-mg or 25-mg led to less FEV1 decline at week 52 vs placebo for patients regardless of on-study exacerbation (no exacerbation: -42mL, -8mL, vs -48mL; ≥1 exacerbation: -59mL, -41mL, vs -70mL, for 10-mg, 25-mg brensocatib and placebo, respectively [Figure]). In the overall population, no change or an improvement (≥0 mL difference vs baseline) in post-BD FEV1 at week 52 was observed in 38.7%, 45.4%, and 31.2% of patients in the brensocatib 10-mg, 25-mg, and placebo groups, respectively. Similar impacts of brensocatib were observed in FVC (no change or improvement, 10-mg: 41.3%; 25-mg: 48.9%; placebo: 31.8%). Conclusions Overall, greater lung function decline was observed in patients who had on-study pulmonary exacerbations vs those who did not. Brensocatib 25-mg reduced lung function decline vs placebo regardless of whether patients had on-study exacerbations, consistent with overall ASPEN results.

Abstract Rationale: Fibrotic interstitial lung diseases (f-ILDs) often lead to increased dyspnea and decreased physical activity, negatively impacting patient quality of life. While center-based pulmonary rehabilitation (PR) provides known benefits, access and adherence may be limited. This study investigates the implementation of a home-based pulmonary rehabilitation program with telephonic health coaching to improve physical activity and respiratory-related quality of life (RR-QOL) over 12 weeks. Methods: This prospective, single-center, non-randomized study enrolled patients with various f-ILD subtypes and severities over two years. Participants engaged in video-based exercises (25 minutes/day, 6 days per week) with weekly telephonic health coaching. Primary outcomes included changes in average daily steps, dyspnea (modified Medical Research Council (mMRC)), and self-reported RR-QOL (Chronic Respiratory Questionnaire (CRQ)- Physical and Emotional Summary domain scores). Minimal Clinically Important Differences (MCID) for study endpoints were defined as ≥600 steps per day, 1-point change in mMRC, and 0.5-point change in CRQ Physical and Emotional Summary scores, used to stratify patient responses to intervention as improved, stable, or worsened. Pre- and post-intervention summary results were compared using paired two-sample t-tests. The percentage of patients reaching MCID thresholds for improvement in primary endpoints was also reported. Results: 88 patients completed the program (mean age 70.2 years, 54% male, and mean FVC 66.9%). Mean CRQ Physical Summary scores improved from baseline 4.09 to 4.35 (mean improvement of 0.26 with 95% CI [0.06, 0.46]). 35% of patients achieved MCID change in the CRQ Physical Summary score, 34% in the CRQ Emotional score, and 22% in mMRC. Although 24% of patients increased their daily steps by 600 or more, average daily steps declined from 7,594 to 7,103 (mean decrease of 492 with 95% CI [101, 883]). When stratified by outcome responses to intervention (improved, stable, or worsened), lower baseline DLCO% was associated with decreased CRQ Physical Summary Scores and daily steps. Conclusion: Home-based PR may improve self-reported quality of life in f-ILD patients, as evidenced by improved CRQ Physical Summary scores. DLCO% may be associated with poorer response to PR intervention, as lower values were associated with declines in CRQ Physical Summary scores and daily steps. These findings support the potential utility of home-based rehabilitation and customizing individual strategies according to baseline characteristics and background disease progression.