Nontuberculous mycobacterial and Aspergillus infections among cadaveric lung transplant recipients in Japan

BACKGROUND

Lung transplantation is an effective treatment modality for respiratory failure. Chronic lung infections, including infections caused by nontuberculous mycobacteria (NTM) and Aspergillus, are difficult to control, and uncontrolled infections are relative contraindications for lung transplantation. However, few reports have documented the incidence and outcome of these infections in lung transplant recipients.

METHODS

To quantify the incidence and outcomes of colonization and disease caused by NTM and aspergillosis in recipients before and after lung transplantation, we reviewed the medical records and microbiology data from 240 consecutive cadaveric lung transplant recipients between 2000 and 2014.

RESULTS

Before lung transplantation, NTM and Aspergillus species were isolated from five (2.1%) and six (2.5%) patients, respectively, out of the total 240 recipients. All patients with NTM infection received treatment, resulting in culture conversion. They had no recurrence after lung transplantation. All patients with aspergillosis received treatment, one of whom had recurrence after lung transplantation. Over a median follow-up period of 3.3 years, NTM species were isolated after transplantation from eight of 240 patients (3.3%). Five of these patients met the criteria for NTM disease, and four of them received treatment. Four patients survived without a worsening of NTM disease. Over the same median follow-up period, Aspergillus species were isolated from seven of 240 patients (2.9%), six of whom received treatment.

CONCLUSIONS

Isolation of NTM or Aspergillus species from lung transplant recipients is uncommon. Adequate pre-transplant control and post-transplant management of NTM and Aspergillus infections allows for safe lung transplantation.

Pneumatosis intestinalis after lung transplantation for pulmonary graft-versus-host disease

Pneumatosis intestinalis, which could complicate a spectrum of clinical conditions ranging from benign to life-threatening, is a rarely encountered complication after lung transplantation (LT). We describe two cases in which PI developed as a complication following LT for pulmonary graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation (HSCT). In addition to the long-term immunosuppression administered for pulmonary GVHD, the intense immunosuppression needed after LT might increase the risk of PI in lung transplant recipients after HSCT. Conservative therapy should be considered for the treatment of PI developing after LT.

Successful Lung Transplantation for Pulmonary Disease Associated With Erdheim-Chester Disease

A 53-year-old man with pulmonary fibrosis associated with Erdheim-Chester disease achieved long-term survival after lung transplantation. Major clinical manifestations included lung and bone injuries, and other vital organs were functionally unaffected by the disease. After a careful observation for the disease progression, he underwent bilateral deceased-donor lung transplantation. He has returned to his normal social life and is doing well without recurrence of Erdheim-Chester disease in the lung allograft or progression in other organs 5 years after transplant. Lung transplantation is a potentially reasonable treatment option for Erdheim-Chester disease involving the lungs if the functions of other vital organs remain stable.

High Frequency of Acute Adverse Cardiovascular Events After Lung Transplantation in Patients With Pulmonary Arterial Hypertension Receiving Preoperative Long-Term Intravenous Prostacyclin

Adverse cardiovascular events after lung transplantation (LT) increase the mortality in patients with pulmonary arterial hypertension (PAH). Long-term intravenous prostacyclin is the usual treatment in severe patients with PAH, but it may increase the risk of hemorrhage due to its antiplatelet aggregation effect or thrombocytopenia. We investigated the impact of length of intravenous prostacyclin therapy on acute adverse cardiovascular events including hemorrhagic complication after LT. We retrospectively compared the incidence of adverse events (death, intrathoracic hematoma and bleeding, cardiac congestion or shock, cerebral infarction and pulmonary embolism) within 30 days after LT between no/short-term (median 0.6 years, n = 13) and long-term (median 3.7 years, n = 15) intravenous prostacyclin groups. There were no differences in the dose of intravenous prostacyclin and pulmonary artery pressure between the two groups. Among 22 adverse events (0.8 ± 1.1 events/patient), 4 events occurred in the no/short-term intravenous prostacyclin group and 18 occurred in the long-term intravenous prostacyclin group. The event rate per patient in the long-term intravenous prostacyclin group (1.2 ± 1.3 events/patient) was significantly higher than that in the no/short-term intravenous prostacyclin group (0.3 ± 0.5 events/patient) (P < 0.05). Intrathoracic hematoma and bleeding was the most frequent adverse event (9 events, 41%). Preoperative long-term intravenous prostacyclin therapy increases acute adverse cardiovascular events after LT in patients with PAH.

Clinical characteristics of Japanese candidates for lung transplant for interstitial lung disease and risk factors for early death while on the waiting list

BACKGROUND

Lung transplants have produced very favorable outcomes for patients with interstitial lung disease (ILD) in Japan. However, because of the severe donor lung shortage, patients must wait approximately 2.5 years before they can undergo transplantation and many candidates die before allocation. We reveal the clinical characteristics of Japanese patients with ILD who are candidates for lung transplants and the risk factors for early death while on the waiting list.

METHODS

We retrospectively reviewed the clinical data of patients registered in the Japan Organ Transplant Network from Okayama University Hospital who are candidates for cadaveric lung transplants for ILD between 1999 and 2015.

RESULTS

Fifty-three patients with ILD were included (24 patients with idiopathic pulmonary fibrosis and 29 others). They had severe pulmonary dysfunction and low exercise tolerability. The median waiting time for transplantation was 462 days, and 22 patients died before allocation. Patients who died before 462 days without undergoing transplantation had more severe dyspnea, shorter 6-minute walk distance (6MWD), and lower performance status than those who waited ≥462 days.

CONCLUSIONS

Japanese candidates for cadaveric lung transplants for ILD have severe pulmonary dysfunction. Severe dyspnea, short 6MWD, and low performance status are risk factors for early death while on the waiting list.

High resolution x-ray absorption and emission spectroscopy of Li x CoO2 single crystals as a function delithiation

The effect of delithiation in Li _x CoO₂ is studied by high resolution Co K-edge x-ray absorption and x-ray emission spectroscopy. Polarization dependence of the x-ray absorption spectra on single crystal samples is exploited to reveal information on the anisotropic electronic structure. We find that the electronic structure of Li _x CoO₂ is significantly affected by delithiation in which the Co ions oxidation state tending to change from 3+  to 4+. The Co intersite (intrasite) 4p-3d hybridization suffers a decrease (increase) by delithiation. The unoccupied 3d t _2g orbitals with a _1g symmetry, containing substantial O 2p character, hybridize isotropically with Co 4p orbitals and likely to have itinerant character unlike anisotropically hybridized 3d e _g orbitals. Such a peculiar electronic structure could have significant effect on the mobility of Li in Li _x CoO₂ cathode and hence the battery characteristics.

Balloon-expandable Metallic Stents for Airway Diseases

Stent placement is an essential treatment for airway diseases. Although self-expandable metallic stents and silicone stents are commonly applied for the treatment of airway diseases, these stents are unsuitable for the treatment of small airway diseases encountered in pediatric patients and lung transplant recipients with airway complications. Currently, only vascular balloon-expandable metallic stents are available for the treatment of small airway diseases; however, little research has been conducted on the use of these stents in this field. We have launched a prospective feasibility study to clarify the safety and efficacy of balloon-expandable metallic stents for the treatment of airway diseases.

[Overview of Clinical Issues after Lung Transplantation]

Lung allograft encounters changeable issues over the pre-and postransplant period. It is important to realize individual problems in each specific peritransplant stage and share the awareness between transplant team and patients. Long-sighted management policy is encouraged throughout posttransplant care because morbidities in each stage trigger each other and graft condition and management in acute posttransplant period have a considerable impact on long-term recipient survival after lung transplantation. The specific issues at hand are reviewed by going through the current important literature.

Visualization of bronchial circulation at bronchial anastomotic site using bronchial fluorescein angiography technique

OBJECTIVES

Successful bronchial healing after a bronchoplastic procedure mainly depends on bronchial circulation at the anastomostic site. We developed a bronchial fluorescein angiography (B-FAG) technique for visualizing circulation on the bronchial surface. The technique was evaluated in animals.

METHODS

Fluorescein was used as a contrast agent and an autofluorescence imaging (AFI) bronchoscope as a detector. The left main pulmonary artery (PA) and main bronchus of 10 pigs were isolated. After transection of the left main bronchus and bronchial arteries and re-anastomosis of the bronchus, the pigs were randomly divided into two groups: the PA- group (n = 5), in which the pulmonary artery was transected; and the PA+ group (n = 5), in which the pulmonary artery was preserved. Following intravenous injection of fluorescein, the distal anastomotic site was observed for 30 min with autofluorescence imaging bronchoscopy. Bronchial specimens sampled 2 days after the surgical intervention were histologically evaluated.

RESULTS

In the PA- group, there was no fluorescein enhancement in the distal bronchus throughout the observation time. However, enhancement, which turned the bronchial surface from magenta to bright green, was clearly observed in less than 207 ± 102.5 s in the PA+ group. The enhancement status detected by bronchial fluorescein angiography was related to the extent of tissue damage, as was proven histologically in the acute healing stage.

CONCLUSIONS

Bronchial fluorescein angiography clearly visualized the circulatory status promptly after the anastomosis procedure at the central bronchus. This technique is a potentially practical approach to predict ischaemic airway complications following bronchial anastomosis.

Lung transplantation for diffuse panbronchiolitis: 5 cases from a single centre

Diffuse panbronchiolitis is a rare complex genetic disease predominantly affecting East Asians, and is characterized by chronic inflammation of the respiratory bronchioles and sinobronchial infection. Although long-term macrolide therapy has been shown to significantly improve the survival in patients with diffuse panbronchiolitis, some patients continue to deteriorate, eventually requiring lung transplantation. However, lung transplantation for diffuse panbronchiolitis has rarely been reported and the outcome in these patients remains unknown. We describe our experience of lung transplantation for diffuse panbronchiolitis. A total of 5 patients received long-term macrolide therapy and had airway colonization by Pseudomonas aeruginosa preoperatively. Three patients had undergone sinus surgery for chronic rhinosinusitis before the transplantation. Bilateral cadaveric lung transplantation was performed in 4 patients, and living-donor lung transplantation in 1. After the lung transplantation, 1 patient developed an A3 acute rejection episode; however, none of the recipients developed severe pneumonia or any fatal infections. One recipient developed chronic lung allograft dysfunction 3 years after the transplantation; however, none developed recurrence of diffuse panbronchiolitis. All of the 5 patients were still surviving after a median follow-up period of 4.9 years (3.7-12.3 years). Lung transplantation is a viable option for the treatment of progressive diffuse panbronchiolitis resistant to long-term macrolide therapy.

Isolation and characterization of dental epithelial cells derived from amelogenesis imperfecta rat

OBJECTIVE

Disruption of the third zinc finger domain of specificity protein 6 (SP6) presents an enamel-specific defect in a rat model of amelogenesis imperfecta (AMI rats). To understand the molecular basis of amelogenesis imperfecta caused by the Sp6 mutation, we established and characterized AMI-derived rat dental epithelial (ARE) cells.

MATERIALS AND METHODS

ARE cell clones were isolated from the mandibular incisors of AMI rats, and amelogenesis-related gene expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Localization of wild-type SP6 (SP6WT) and mutant-type SP6 (SP6AMI) was analyzed by immunocytochemistry. SP6 transcriptional activity was monitored by rho-associated protein kinase 1 (Rock1) promoter activity with its specific binding to the promoter region in dental (G5 and ARE) and non-dental (COS-7) epithelial cells.

RESULTS

Isolated ARE cells were varied in morphology and gene expression. Both SP6WT and SP6AMI were mainly detected in nuclei. The promoter analysis revealed that SP6WT and SP6AMI enhanced Rock1 promoter activity in G5 cells but that enhancement by SP6AMI was weaker, whereas no enhancement was observed in the ARE and COS-7 cells, even though SP6WT and SP6AMI bound to the promoter in all instances.

CONCLUSION

ARE cell clones can provide a useful in vitro model to study the mechanism of SP6-mediated amelogenesis imperfecta.