Lymphangioleiomyomatosis: New Treatment Perspectives

Single lung transplantation for lymphangioleiomyomatosis: a single-center experience in Japan

PURPOSE

Lung transplantation is accepted as an effective modality for patients with end-stage pulmonary lymphangioleiomyomatosis (LAM). Generally, bilateral lung transplantation is preferred to single lung transplantation (SLT) for LAM because of native lung-related complications, such as pneumothorax and chylothorax. It remains controversial whether SLT is a suitable surgical option for LAM. The objective of this study was to evaluate the morbidity, mortality and outcome after SLT for LAM in a lung transplant center in Japan.

METHODS

We reviewed the records of 29 patients who underwent SLT for LAM in our hospital between March, 2000 and November, 2017. The data collected included the pre-transplant demographics of recipients, surgical characteristics, complications, morbidity, mortality and survival after SLT for LAM.

RESULTS

The most common complication after SLT for LAM was contralateral pneumothorax (n = 7; 24.1%). Six of these recipients were treated successfully with chest-tube placement and none required surgery for the pneumothorax. The second-most common complication was chylous pleural effusion (n = 6; 20.7%) and these recipients were all successfully treated by pleurodesis. The 5-year survival rate after SLT for LAM was 79.5%.

CONCLUSION

LAM-related complications after SLT for this disease can be managed. SLT is a treatment option and may improve access to lung transplantation for patients with end-stage LAM.

Metabolic Impact of Rapamycin (Sirolimus) and B-Estradiol Using Mouse Embryonic Fibroblasts as a Model for Lymphangioleiomyomatosis

INTRODUCTION

Lymphangioleiomyomatosis (LAM) is a rare, progressive cystic lung disease that predominantly affects women of childbearing age. Exogenous rapamycin (sirolimus) has been shown to improve clinical outcomes and was recently approved to treat LAM, whereas estrogen (E₂) is implicated in disease progression. No consistent metabolic model currently exists for LAM, therefore wild-type mouse embryonic fibroblasts (MEF +/+) and TSC2 knockout cells (MEF -/-) were used in this study as a model for LAM.

METHODS

Oxygen consumption rates (OCR) and redox potential were measured to determine metabolic state across control cells, MEF +/+ and -/- cells treated with rapamycin (Rapa), and MEF +/+ and -/- cells treated with E₂. An XF96 extracellular flux analyzer from Seahorse Bioscience^® was used to measure OCR, and a RedoxSYS™ ORP was used to measure redox potential.

RESULTS

OCR of MEF -/- cells treated with rapamycin (MEF -/- Rapa) versus MEF -/- control were significantly lower across all conditions. The static oxidation reduction potential of the MEF -/- Rapa group was also lower, approaching significance. The coupling efficiency and ratio of ATP-linked respiration to maximum respiration were statistically lower in MEF -/- Rapa compared to MEF +/+ Rapa. There were no significant metabolic findings across any of the MEF cells treated with E₂. MEF -/- control cells versus MEF +/+ control cells were not found to significantly differ.

CONCLUSION

MEF cells are thought to be a feasible metabolic model for LAM, which has implications for future pharmacologic and biologic testing.

Multiple cystic lung disease

Multiple cystic lung disease represents a diverse group of uncommon disorders that can present a diagnostic challenge due to the increasing number of diseases associated with this presentation. High-resolution computed tomography of the chest helps to define the morphological aspects and distribution of lung cysts, as well as associated findings. The combination of appearance upon imaging and clinical features, together with extrapulmonary manifestations, when present, permits confident and accurate diagnosis of the majority of these diseases without recourse to open-lung biopsy. The main diseases in this group that are discussed in this review are lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis and folliculin gene-associated syndrome (Birt–Hogg–Dubé); other rare causes of cystic lung disease, including cystic metastasis of sarcoma, are also discussed. Disease progression is unpredictable, and understanding of the complications of cystic lung disease and their appearance during evolution of the disease are essential for management. Correlation of disease evolution and clinical context with chest imaging findings provides important clues for defining the underlying nature of cystic lung disease, and guides diagnostic evaluation and management.