Lung transplantation

Interstitial Lung Disease: A Focused Review for the Emergency Clinician

BACKGROUND

Interstitial lung disease (ILD) is a group of restrictive pulmonary diseases associated with diffuse interstitial and parenchymal inflammation. Patients can present to the emergency department with severe exacerbation.

OBJECTIVE

This narrative review provides emergency clinicians with the most recent evidence concerning acute exacerbation of ILD (AE-ILD).

DISCUSSION

AE-ILD can present as acute respiratory distress in a patient with a pre-existing ILD diagnosis or as a de novo presentation of ILD, and is associated with significant morbidity and mortality. A variety of underlying triggers may result in AE-ILD. Emergency clinicians must first assess for extraneous causes of respiratory decompensation prior to diagnosing AE-ILD. For a de novo presentation of ILD, emergency physicians should also assess for possible reversible causes. AE-ILD is managed with systemic steroids, immunosuppressants, intravenous antibiotics, supplemental oxygen, and extracorporeal membrane oxygenation in severe cases. Given the high mortality rates in the absence of lung transplantation, early referral to transplant centers is essential to increase chances of survival.

CONCLUSIONS

Emergency clinician knowledge of AE-ILD can improve the evaluation and management of these patients.

Novel Role of miR-18a-5p and Galanin in Rat Lung Ischemia Reperfusion-Mediated Response

Lung ischemia reperfusion (IR) is known to occur after lung transplantation or cardiac bypass. IR leads to tissue inflammation and damage and is also associated with increased morbidity and mortality. Various receptors are known to partake in activation of the innate immune system, but the downstream mechanism of tissue damage and inflammation is yet unknown. MicroRNAs (miRNAs) are in the forefront in regulating ischemia reperfusion injury and are involved in inflammatory response. Here, we have identified by high-throughput approach and evaluated a distinct set of miRNAs that may play a role in response to IR in rat lung tissue. The top three differentially expressed miRNAs were validated through quantitative PCRs in the IR rat lung model and an in vitro model of IR of hypoxia and reoxygenation exposed type II alveolar cells. Among the miRNAs, miR-18a-5p showed consistent downregulation in both the model systems on IR. Cellular and molecular analysis brought to light a crucial role of this miRNA in ischemia reperfusion. miR-18a-5p plays a role in IR-mediated apoptosis and ROS production and regulates the expression of neuropeptide Galanin. It also influences the nuclear localization of transcription factor: nuclear factor-erythroid 2-related factor (Nrf2) which in turn may regulate the expression of the miR-18a gene. Thus, we have not only established a rat model for lung IR and enumerated the important miRNAs involved in IR but have also extensively characterized the role of miR-18a-5p. This study will have important clinical and therapeutic implications for and during transplantation procedures.

Simultaneous analysis of drugs administered to lung-transplanted patients using liquid chromatography-tandem mass spectrometry for therapeutic drug monitoring

Several drugs are administered to lung-transplanted patients, which are monitored using therapeutic drug monitoring (TDM). Therefore, we developed and validated a liquid chromatography-tandem mass spectrometry method to simultaneously analyze immunosuppressive drugs such as mycophenolic acid, antifungal drugs such as voriconazole and itraconazole, and its metabolite hydroxyitraconazole. Chromatographic separation was achieved using a C18 column and gradient flow of mobile phase comprising 20 mM aqueous ammonium formate and 20 mM ammonium formate-methanol solution. A simple protein precipitation treatment was performed using acetonitrile/methanol and mycophenolic acid-² H₃ , voriconazole-² H₃ , itraconazole-² H₄ , and hydroxyitraconazole-² H₄ as internal standards. The linearity ranges of mycophenolic acid, voriconazole, itraconazole, and hydroxyitraconazole were 100-20,000, 50-10,000, 5-1000, and 5-1000 ng/mL, respectively. The retention time of each target was less than 2 min. The relative errors in intra- and inter-day were within ±7.6%, the coefficient of variation was 8.9% or less for quality control low, medium, and high, and it was 15.8% or less for lower limit of quantitation. Moreover, the patient samples were successfully quantified, and they were within the linear range of measurements. Therefore, our new method may be useful for TDM in lung-transplanted patients.

Impact of Recruitment Maneuvers to Cover Adverse Effects of Donor Transfer

OBJECTIVES

Our aim was to investigate the negative effects of transferring brain-dead donors to the intensive care unit on the ratio of PaO₂ to inspired oxygen fraction and the benefits of recruitment maneuvers on its reversal.

MATERIALS AND METHODS

In this randomized trial, we assigned 30 brain-dead donors to an intervention group and a control group. After transfer to the intensive care unit, donors in the intervention group received a lung recruitment maneuver according to protocol for 1 hour, whereas the control group did not receive this intervention. Arterial blood gas was drawn before transfer, immediately aftertransfer, and 3 hours after transfer.

RESULTS

Before transfer to immediately after transfer, the PaO₂-to-inspired oxygen fraction ratio decreased from 281.30 ± 100.33 to 225.03 ± 95.72 mm Hg (P < .01). At 3 hours aftertransfer,the PaO₂-to-inspired oxygen fraction ratio in the intervention and control groups was 280.4 ± 120.4 and 213.4 ± 75.5 mm Hg (P = .017), respectively. The absolute difference in PaO₂-to-inspired oxygen fraction ratio from before to 3 hours after transfer was -16.9 ± 44.1 and 51.8 ± 61.4 mm Hg (P < .001), in the intervention and control groups,respectively. Increasing central venous pressure and/or transfer time further potentiated the decrease ofthe PaO₂-to-inspired oxygen fraction ratio.

CONCLUSIONS

The PaO₂-to-inspired oxygen fraction ratio decreased after transfer of brain-dead donors to the intensive care unit. This was partially reversible by standardized recruitment maneuvers.

Protective effects of a hydrogen-rich solution during cold ischemia in rat lung transplantation

BACKGROUND

Molecular hydrogen can reduce the oxidative stress of ischemia-reperfusion injury in various organs for transplantation and potentially improve survival rates in recipients. This study aimed to evaluate the protective effects of a hydrogen-rich preservation solution against ischemia-reperfusion injury after cold ischemia in rat lung transplantation.

METHODS

Lewis rats were divided into a nontransplant group (n = 3), minimum-ischemia group (n = 3), cold ischemia group (n = 6), and cold ischemia with hydrogen-rich (more than 1.0 ppm) preservation solution group (n = 6). The rats in the nontransplant group underwent simple thoracotomy, and the rats in the remaining 3 groups underwent orthotopic left lung transplantation. The ischemic time was <30 minutes in the minimum-ischemia group and 6 hours in the cold ischemia groups. After 2-hour reperfusion, we evaluated arterial blood gas levels, pulmonary function, lung wet-to-dry weight ratio, and histologic features of the lung tissue. The expression of proinflammatory cytokines was measured using quantitative polymerase chain reaction assays, and 8-hydroxydeoxyguanosine levels were evaluated using enzyme-linked immunosorbent assays.

RESULTS

When compared with the nontransplant and minimum-ischemia groups, the cold ischemia group had lower dynamic compliance, lower oxygenation levels, and higher wet-to-dry weight ratios. However, these variables were significantly improved in the cold ischemia with hydrogen-rich preservation solution group. This group also had fewer signs of perivascular edema, lower interleukin-1β messenger RNA expression, and lower 8-hydroxydeoxyguanosine levels than the cold ischemia group.

CONCLUSIONS

The use of a hydrogen-rich preservation solution attenuates ischemia-reperfusion injury in rat lungs during cold ischemia through antioxidant and anti-inflammatory effects.

Mitigation of Primary Graft Dysfunction in Lung Transplantation: Current Understanding and Hopes for the Future

Primary graft dysfunction (PGD) is a form of acute lung injury that develops within the first 72 hours after lung transplantation. The overall incidence of PGD is estimated to be around 30%, and the 30-day mortality for grade 3 PGD around 36%. PGD is also associated with the development of bronchiolitis obliterans syndrome, a specific form of chronic lung allograft dysfunction. In this article, we will discuss perioperative strategies for PGD prevention as well as possible future avenues for prevention and treatment.

Unilateral Chronic Lung Allograft Dysfunction Assessed by Biphasic Computed Tomographic Volumetry in Bilateral Living-donor Lobar Lung Transplantation

Background

Early diagnosis of unilateral chronic lung allograft dysfunction (CLAD) is difficult because the unaffected contralateral lung functions as a reservoir in bilateral living-donor lobar lung transplantation (LDLLT). We previously reported the usefulness of ¹³³Xe ventilation scintigraphy for detection of unilateral change, but the supply of ¹³³Xe has been stopped globally. The present study aimed to examine the usefulness of inspiratory and expiratory computed tomography (I/E CT) volumetry for detection of unilateral change in CLAD patients.

Methods

This was a retrospective single-center, observational study using prospectively collected data. A total of 58 patients who underwent bilateral LDLLT from August 2008 to February 2017 were analyzed. Respiratory function tests, I/E CT were prospectively conducted. ΔLung volume was defined as the value obtained by subtracting expiratory lung volume from inspiratory lung volume.

Results

Fourteen (24%) cases were clinically diagnosed with CLAD, of which 10 (71%) were diagnosed as unilateral CLAD. ΔLung volume of bilateral lungs strongly correlated with forced vital capacity (r = 0.92, P < 0.01) and forced expiratory volume in 1 second (r = 0.80, P < 0.01). Regardless the phenotypes (bronchiolitis obliterans syndrome or restrictive allograft syndrome) of CLAD, Δlung volume onset/baseline significantly decreased compared with that in the non-CLAD group. Among the 10 unilateral CLAD patients, 3 with clinically suspected unilateral rejection yet did not show a 20% decline in forced expiratory volume in 1 second. In 2 of these, Δlung volume of unilateral lungs on the rejection side decreased by 20% or more.

Conclusions

Our findings suggest that I/E CT volumetry may be useful for assessment and early diagnosis of unilateral CLAD after bilateral LDLLT.

Pulmonary fibrosis, part II: state-of-the-art patient management

INTRODUCTION

While many pharmacologic therapies for the treatment of idiopathic pulmonary fibrosis (IPF) have been evaluated via randomized, placebo-controlled clinical trials (RCTs) conducted over the past two decades, most therapies have been shown to be ineffective or even potentially harmful. However, a number of recently completed RCTs have shown significant efficacy for pirfenidone and nintedanib for the treatment of IPF. Areas covered: This manuscript reviews recent advances in the management of IPF and other forms of fibrosing interstitial lung disease (ILD) with an emphasis on IPF. The material upon which this discussion is based was obtained from various published texts and manuscripts identified via literature searching (e.g. PubMed). Expert commentary: Anti-fibrotic drugs are now available for clinical use and perceived as standard-of-care therapies that have the potential to blunt disease progression for many patients with IPF. However, these agents do not necessarily stop disease progression or have a significant impact on mortality, and more effective pharmacologic therapies are needed for patients with IPF. Additionally, whether anti-fibrotic agents can be effective therapies for other forms of pulmonary fibrosis, which often have radiologic and histopathologic manifestations that mimic IPF, is being evaluated in a number of RCTs.

Primary Graft Dysfunction after Lung Transplantation

Primary graft dysfunction (PGD) is a severe form of acute lung injury that is a major cause of early morbidity and mortality encountered after lung transplantation. PGD is diagnosed by pulmonary oedema with diffuse alveolar damage that manifests clinically as progressive hypoxemia with radiographic pulmonary infiltrates. Inflammatory and immunological response caused by ischaemia and reperfusion is important with regard to pathophysiology. PGD affects short- and long-term outcomes, the donor organ is the leading factor affecting these adverse ramifications. To minimize the risk of PGD, reduction of lung ischaemia time, reperfusion optimisation, prostaglandin level regulation, haemodynamic control, hormone replacement therapy, ventilator management are carried out; for research regarding donor lung preparation strategies, certain procedures are recommended. In this review, recent updates in epidemiology, pathophysiology, molecular and genetic biomarkers and technical developments affecting PGD are described.

Practical guidelines: lung transplantation in patients with cystic fibrosis

There are no European recommendations on issues specifically related to lung transplantation (LTX) in cystic fibrosis (CF). The main goal of this paper is to provide CF care team members with clinically relevant CF-specific information on all aspects of LTX, highlighting areas of consensus and controversy throughout Europe. Bilateral lung transplantation has been shown to be an important therapeutic option for end-stage CF pulmonary disease. Transplant function and patient survival after transplantation are better than in most other indications for this procedure. Attention though has to be paid to pretransplant morbidity, time for referral, evaluation, indication, and contraindication in children and in adults. This review makes extensive use of specific evidence in the field of lung transplantation in CF patients and addresses all issues of practical importance. The requirements of pre-, peri-, and postoperative management are discussed in detail including bridging to transplant and postoperative complications, immune suppression, chronic allograft dysfunction, infection, and malignancies being the most important. Among the contributors to this guiding information are 19 members of the ECORN-CF project and other experts. The document is endorsed by the European Cystic Fibrosis Society and sponsored by the Christiane Herzog Foundation.

Calcineurin inhibitors: 40 years later, can't live without

Calcineurin inhibitors (CNIs) revolutionized the field of organ transplantation and remain the standard of care 40 years after the discovery of cyclosporine. The early impressive results of cyclosporine in kidney transplant recipients led to its subsequent use in other organ transplant recipients and for treatment of a variety of autoimmune diseases as well. In this review, we examine the discovery of CNIs, their mechanism of action, preclinical and clinical studies with CNIs, and the usage of CNIs in nontransplant recipients. We review the mechanisms of renal toxicity associated with CNIs and the recent efforts to avoid or reduce usage of these drugs. Although minimization strategies are possible, safe, and of potential long-term benefit, complete avoidance of CNIs has proven to be more challenging than initially thought.

Diagnosis and management of interstitial lung disease

The complex tasks of making a confident diagnosis of a specific form of interstitial lung disease (ILD) and formulating a patient-centered, personalized management plan in an attempt to achieve remission or stabilization of the disease process can pose formidable challenges to clinicians. When patients are evaluated for suspected ILD, an accurate diagnosis of the specific form of ILD that a patient has developed must be made to provide the patient with useful prognostic information and to formulate an appropriate management plan that can relieve symptoms and restore or significantly improve quality of life. A well-performed patient history and physical examination provides invaluable information that can be combined with appropriate laboratory testing, imaging, and, if needed, tissue biopsy to reach a confident ILD diagnosis, and high-resolution computed tomography (HRCT) of the thorax is usually a key component of the diagnostic evaluation. If treatment is indicated, many forms of ILD can respond significantly to immunosuppressive anti-inflammatory therapies. However, ILD accompanied by extensive fibrosis may be difficult to treat, and the identification of an effective pharmacologic therapy for idiopathic pulmonary fibrosis (IPF) has remained elusive despite the completion of many phase 3 clinical trials over the past decade. Nonetheless, patients with IPF or advanced forms of non-IPF ILD can benefit significantly from detection and treatment of various co-morbid conditions that are often found in patients (especially the elderly patient), and supportive care (oxygen therapy, pulmonary rehabilitation) can have a beneficial impact on quality of life and symptom palliation. Finally, lung transplantation is an option for patients with progressive, advanced disease that does not respond to other therapies, but only a relatively small subset of patients with end-stage ILD are able to meet wait listing requirements and eventually undergo successful lung transplantation.