19 research outputs found
Lung Transplantation in a Patient with COVID-19-Associated Acute Respiratory Failure
Coronavirus disease 2019 (COVID-19) is currently a significant cause of acute respiratory failure worldwide, leading to irreversible fibrotic lung disease. In patients with persistent respiratory failure after acute COVID-19 infection, lung transplant is an emerging option. Here, we have presented a case where the patient required venovenous extracorporeal membrane oxygenation (VV-ECMO) support for 33 days until a bilateral lung transplant was performed on day 71 after the initial COVID-19 infection. The early outcomes have been favorable. Currently, no guidelines exist for an acceptable time period after initial COVID-19 infection, duration of negative COVID polymerase chain reaction (PCR) testing, or negative Vero cell culture in the setting of persistent positive COVID PCR testing before listing for a lung transplant. Due to a lack of standardized guidelines, this patient was not listed for a lung transplant until the COVID-19 PCRs came negative on days 47 and 49 after the infection
Pregabalin-Induced Myopathy in a Double Lung Transplant Recipient
Pregabalin is a gamma-aminobutyric acid (GABA) derivative that was commercially approved by the Food and Drug Administration (FDA) in 2004. It is commonly used in the treatment of diabetic neuropathy, peripheral neuropathy, and spinal cord injury. We present the case of a 36-year-old Caucasian male double lung transplant recipient who presented with an 18-month history of fatigue and muscle weakness. He had elevated creatinine kinase level and his muscle biopsy showed evidence of drug-induced myopathy that improved after the cessation of pregabalin. We present a case of drug-induced myopathy as a rare complication of pregabalin therapy in a double lung transplant recipient
Report of the ISHLT Working Group on Primary Lung Graft Dysfunction Part III: Mechanisms: A 2016 Consensus Group Statement of the International Society for Heart and Lung Transplantation
Inspiratory muscle strength training improves weaning outcome in failure to wean patients: a randomized trial
Pleural mesothelial cell transformation into myofibroblasts and haptotactic migration in response to TGF-β1 in vitro
Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology characterized by the development of subpleural foci of myofibroblasts that contribute to the exuberant fibrosis noted in the pulmonary parenchyma. Pleural mesothelial cells (PMC) are metabolically dynamic cells that cover the lung and chest wall as a monolayer and are in intimate proximity to the underlying lung parenchyma. The precise role of PMC in the pathogenesis of pulmonary parenchymal fibrosis remains to be identified. Transforming growth factor (TGF)-β1, a cytokine known for its capacity to induce proliferative and transformative changes in lung cells, is found in significantly higher quantities in the lungs of patients with IPF. High levels of TGF-β1 in the subpleural milieu may play a key role in the transition of normal PMC to myofibroblasts. Here we demonstrate that PMC activated by TGF-β1 undergo epithelial-mesenchymal transition (EMT) and respond with haptotactic migration to a gradient of TGF-β1 and that the transition of PMC to myofibroblasts is dependent on smad-2 signaling. The EMT of PMC was marked by upregulation of α-smooth muscle actin (α-SMA), fibroblast specific protein-1 (FSP-1), and collagen type I expression. Cytokeratin-8 and E-cadherin expression decreased whereas vimentin remained unchanged over time in transforming PMC. Knockdown of smad-2 gene by silencing small interfering RNA significantly suppressed the transition of PMC to myofibroblasts and significantly inhibited the PMC haptotaxis. We conclude that PMC undergo EMT when exposed to TGF-β1, involving smad-2 signaling, and PMC may be a possible source of myofibroblasts in IPF
Purification and biochemical characterization of taxadiene synthase from bacillus koreensis and stenotrophomonas maltophilia
Taxadiene synthase (TDS) is the rate-limiting enzyme of Taxol biosynthesis that cyclizes the geranylgeranyl pyrophosphate into taxadiene. Attenuating Taxol productivity by fungi is the main challenge impeding its industrial application; it is possible that silencing the expression of TDS is the most noticeable genomic feature associated with Taxol-biosynthetic abolishing in fungi. As such, the characterization of TDS with unique biochemical properties and autonomous expression that is independent of transcriptional factors from the host is the main challenge. Thus, the objective of this study was to kinetically characterize TDS from endophytic bacteria isolated from different plants harboring Taxol-producing endophytic fungi. Among the recovered 23 isolates, Bacillus koreensis and Stenotrophomonas maltophilia achieved the highest TDS activity. Upon using the Plackett–Burman design, the TDS productivity achieved by B. koreensis (18.1 µmol/mg/min) and S. maltophilia (14.6 µmol/mg/min) increased by ~2.2-fold over the control. The enzyme was purified by gel-filtration and ion-exchange chromatography with ~15 overall folds and with molecular subunit structure 65 and 80 kDa from B. koreensis and S. maltophilia, respectively. The chemical identity of taxadiene was authenticated from the GC-MS analyses, which provided the same mass fragmentation pattern of authentic taxadiene. The tds gene was screened by PCR with nested primers of the conservative active site domains, and the amplicons were sequenced, displaying a higher similarity with tds from T. baccata and T. brevifolia. The highest TDS activity by both bacterial isolates was recorded at 37–40 °C. The Apo-TDSs retained ~50% of its initial holoenzyme activities, ensuring their metalloproteinic identity. The activity of purified TDS was completely restored upon the addition of Mg2+, confirming the identity of Mg2+ as a cofactor. The TDS activity was dramatically reduced upon the addition of DTNB and MBTH, ensuring the implementation of cysteine-reactive thiols and ammonia groups on their active site domains. This is the first report exploring the autonomous robust expression TDS from B. koreensis and S. maltophilia with a higher affinity to cyclize GGPP into taxadiene, which could be a novel platform for taxadiene production as intermediary metabolites of Taxol biosynthesis
Two Decades of Lung Retransplantation: A Single-Center Experience
Lung retransplantation (ReTx) comprises an increasing share of lung transplants and recently has shown improved outcomes. The aim of this study was to identify risk factors affecting overall survival after pulmonary ReTx.
The United Network for Organ Sharing database was used to identify patients undergoing lung transplantation at our institution from 1995 to 2014. Of the total 542 lung transplants performed, 87 (16.1%) were ReTxs. The primary outcome was overall survival. Multivariate Cox regression models were used to assess the effect of recipient and donor characteristics on survival.
Of the patients who underwent ReTx, median survival was 2 years. Predictors of worse survival include recipient age between 50 and 60 years (relative risk, 4.3; p = 0.02) or older than 60 years (relative risk, 10.2; p < 0.001), and time to ReTx of less than 2 years (relative risk, 3.8; p = 0.01). ReTx for bronchiolitis obliterans syndrome had longer median survival than for restrictive chronic lung allograft dysfunction (2.7 years vs 0.9 years; p = 0.055). Overall survival of ReTx patients after initiation of the lung allocation score was not significantly different (p = 0.21).
Lung ReTx outcomes are significantly worse than for primary transplantation but may be appropriate in well-selected patients with certain diagnoses. Lung ReTx in patients older than 50 years or within 2 years of primary lung transplantation was associated with decreased survival. Further work is warranted to identify patients who benefit most from ReTx