Pulmonary lymphangiomatosis: a report of two cases.
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Lymphangiomatosis, a rare diseases of controversial origin, occurs in individuals of any age, regardless of gender, but is predominantly seen in younger individuals. It often presents with thoracic involvement, although, the bones, spleen and liver can also be affected. Histologically, the pulmonary involvement includes proliferation, complex anastomoses and secondary dilatation of the lymphatic vessels. Clinically, the presentation is variable. Although radiographic findings can be suggestive of the disease, the final diagnosis is made histologically. We report two cases of lymphangiomatosis, both in females: one was oligosymptomatic and is being treated for the disease; the other had a more progressive form, was diagnosed quite late and ultimately died of the disease. (+info)
Lymphangioleiomyomatosis diagnosed by immunocytochemical and genetic analysis of lymphangioleiomyomatosis cell clusters found in chylous pleural effusion.
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A 37-year-old woman presented with a cough and discomfort in the chest. Computed tomography revealed the right pleural effusion and a number of cysts in the lungs. Thoracentesis revealed LAM cell clusters (LCC) in chylous pleural effusion, confirmed by immunocytochemical examinations showing that the cells at the center of cluster were LAM cells positive for alpha-smooth muscle actin and HMB45 and the outer layer was lymphatic endothelium cells. When LCC were cultured in vitro, the loss of heterozygosity of TSC2 markers was detected. This case illustrates that LAM can be diagnosed by the identification of LCC without an invasive biopsy if complicated with chylous effusion. (+info)
Pulmonary artery pressure in lymphangioleiomyomatosis: an echocardiographic study.
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BACKGROUND: Exercise-induced hypoxemia is frequent in patients with lymphangioleiomyomatosis (LAM) and could be associated with pulmonary hypertension. The aims of this study were to determine the prevalence of pulmonary hypertension in patients with LAM, to identify physiologic parameters associated with its occurrence, and to evaluate the effect of oxygen on response to exercise. METHODS: Studies were performed in 120 patients. Complete data, including exercise echocardiography, pulmonary function testing, and standard cardiopulmonary exercise testing, were obtained in 95 patients. RESULTS: Resting pulmonary artery pressure (PAP) was 26+/-0.7 mm Hg (mean+/-SEM). Eight patients had pulmonary hypertension (43+/-3 mm Hg), and two patients had right ventricular dilatation. Ninety-five patients exercised (room air, n=64; oxygen, n=31) to a power of 58+/-2 W (49% of predicted) and an estimated peak oxygen uptake of 938+/-30 mL/min (56% of predicted). Sixty-one patients had a decline in arterial oxygen saturation (SaO2)>3%, and 56 patients had an elevation in PAP>40 mm Hg. Peak exercise PAP was negatively correlated with exercise Sao2 (p=0.0005). Multivariate analysis showed that exercise SaO2 was the best predictor of exercise PAP (p=0.012). CONCLUSIONS: Although resting pulmonary hypertension is rare in patients with LAM, a rise in PAP at low exercise levels occurs frequently, in part related to exercise-induced hypoxemia. Optimization of oxygen administration during activities of daily living should be undertaken in patients with LAM to prevent hypoxemia and exercise-induced pulmonary hypertension. (+info)
TSC2 loss in lymphangioleiomyomatosis cells correlated with expression of CD44v6, a molecular determinant of metastasis.
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Lymphangioleiomyomatosis (LAM), a rare multisystem disease found primarily in women of childbearing age, is characterized by the proliferation of abnormal smooth muscle-like cells, LAM cells, that form nodules in the pulmonary interstitium. Proliferation of LAM cells results, in part, from dysfunction in tuberous sclerosis complex (TSC) genes TSC1 (hamartin) and/or TSC2 (tuberin). Identification of LAM cells in donor lungs, their isolation from blood, and their presence in urine, chylous ascites, and pleural effusions are consistent with their ability to metastasize. Here, we investigated the presence on LAM cells of the hyaluronic acid receptor CD44 and its splice variants associated with metastasis. The heterogeneous populations of cells grown from lungs of 12 LAM patients contain cells expressing mRNA for the variant CD44v6. Histologically, CD44v6 was present in LAM lung nodules, but not in normal vascular smooth muscle cells. CD44v6-positive sorted cells showed loss of heterozygosity at the TSC2 locus; binding of CD44v6 antibody resulted in loss of cell viability. Levels of CD44 were higher in cultured Eker rat (Tsc2-/-) cells than in Tsc2+/+ cells, but unlike human LAM cells, the Tsc2-/- Eker rat cells did not contain CD44v6 splice variant mRNA. CD44 splicing and signaling is regulated by osteopontin. Plasma from LAM patients contained higher concentrations of osteopontin than plasma of healthy, age-, and sex-matched volunteers (P = 0.00003) and may be a biomarker for LAM. The cell surface receptor CD44 and its splice variant CD44v6 may contribute to the metastatic potential of LAM cells. (+info)
Effect of a gonadotrophin-releasing hormone analogue on lung function in lymphangioleiomyomatosis.
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BACKGROUND: Lymphangioleiomyomatosis (LAM), a multisystem disease occurring primarily in women, is characterized by cystic lung destruction, and kidney and lymphatic tumors, caused by the proliferation of abnormal-appearing cells (ie, LAM cells) with a smooth muscle cell phenotype that express melanoma antigens and are capable of metastasizing. Estrogen receptors are present in LAM cells, and this finding, along with reports of disease progression during pregnancy or following exogenous estrogen administration, suggest the involvement of estrogens in the pathogenesis of LAM. Consequently, antiestrogen therapies have been employed in treatment. The goal of this prospective study was to evaluate the efficacy of triptorelin, a gonadotrophin-releasing hormone analogue, in 11 premenopausal women with LAM. METHODS: Patients were evaluated at baseline and every 3 to 6 months thereafter, for a total of 36 months. Hormonal assays, pulmonary function tests, 6-min walk tests, high-resolution CT scans of the chest, and bone mineral density studies were performed. RESULTS: Gonadal suppression was achieved in all patients. Overall, a significant decline in lung function was observed; two patients underwent lung transplantation 1 year after study enrollment, and another patient was lost to follow-up. Treatment with triptorelin was associated with a decline in bone mineral density. CONCLUSIONS: Triptorelin appears not to prevent a decline in lung function in patients with LAM. Its use, however, may be associated with the loss of bone mineral density. (+info)
Interferon beta augments tuberous sclerosis complex 2 (TSC2)-dependent inhibition of TSC2-null ELT3 and human lymphangioleiomyomatosis-derived cell proliferation.
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Lymphangioleiomyomatosis (LAM), a rare pulmonary disorder, manifests as an abnormal neoplastic growth of smooth muscle-like cells within the lungs. Mutational inactivation of tumor suppressor tuberous sclerosis complex 2 (TSC2) in LAM constitutively activates the mammalian target of rapamycin (mTOR)/p70 S6 kinase 1 (S6K1) signaling pathway and promotes neoplastic growth of LAM cells. In many cell types, type I interferon beta (IFNbeta) inhibits proliferation and induces apoptosis through signal transducers and activators of transcription (STAT)-dependent and STAT-independent signaling pathways, one of which is the mTOR/S6K1 signaling pathway. Our study shows that IFNbeta is expressed in LAM tissues and LAM-derived cell cultures; however, IFNbeta attenuates LAM-derived cell proliferation only at high concentrations, 100 and 1000 U/ml (IC(50) value for IFNbeta is 20 U/ml compared with 1 U/ml for normal human mesenchymal cells, human bronchus fibroblasts and human airway smooth muscle cells). Likewise, IFNbeta only attenuates proliferation of smooth muscle TSC2-null ELT3 cells. Analysis of IFNbeta signaling in LAM cells showed expression of IFNbeta receptor alpha (IFNbetaRalpha) and IFNbetaRbeta, activation and nuclear translocation of STAT1, and phosphorylation of STAT3 and p38 mitogen-activated protein kinase (MAPK), but IFNbeta had little effect on S6K1 activity. However, the re-expression of TSC2 or inhibition of mTOR/S6K1 with rapamycin (sirolimus) augmented antiproliferative effects of IFNbeta in LAM and TSC2-null ELT3 cells. Our study demonstrates that IFNbeta-dependent activation of STATs and p38 MAPK is not sufficient to fully inhibit proliferation of cells with TSC2 dysfunction and that TSC2-dependent inhibition of mTOR/S6K1 cooperates with IFNbeta in inhibiting human LAM and TSC2-null ELT3 cell proliferation. (+info)
Smooth muscle-like cells in pulmonary lymphangioleiomyomatosis.
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Proliferation, migration, and differentiation of smooth muscle (SM)-like lymphangioleiomyomatosis (LAM) cells in the lungs are pathologic manifestations of pulmonary LAM, a rare lung disease predominantly afflicting women and exacerbated by pregnancy. LAM cells form nodules throughout the lung without any predominant localization, but can also form small cell clusters dispersed within lung parenchyma. LAM cells have the appearance of "immature" SM-like cells, irregularly distributed within the nodule in contrast to organized SM cell layers in airways and vasculature. Progressive growth of LAM cells leads to the cystic destruction of the lung parenchyma, obstruction of airways and lymphatics, and loss of pulmonary function. Pathogenetically, LAM occurs from somatic or genetic mutations of tumor suppressor genes tuberous sclerosis complex 1 (TSC1) or TSC2. The TSC1/TSC2 protein complex is an integrator of signaling networks regulated by growth factors, insulin, nutrients, and energy. The observation that the TSC1/TSC2 functions as a negative regulator of the mammalian target of rapamycin (mTOR)/p70 S6 kinase (S6K1) signaling pathway yielded the first rapamycin clinical trial for LAM. Although LAM is a rare lung disease, the elucidation of disease-relevant mechanisms of LAM will provide a better understanding of not only SM-like cell growth, migration, and differentiation in LAM but may also offer insights into other metabolic diseases such as cardiovascular diseases, diabetes, and cancer. In this article, we will summarize the progress made in our understanding of LAM, and we will focus on how dysregulation of TSC1/TSC2 signaling results in abnormal proliferation and migration of SM-like LAM cells. (+info)
Lung transplantation in the management of patients with lymphangioleiomyomatosis: baseline data from the NHLBI LAM Registry.
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BACKGROUND: In 1997, the National Heart, Lung, and Blood Institute of the National Institutes of Health established a Registry to better characterize the demographic, clinical, physiologic and radiographic features of patients with lymphangioleiomyomatosis (LAM). Herein we report data collected at enrollment from patients who had either undergone transplant prior to enrollment, underwent transplant during the 5-year study, or were evaluated/wait-listed for lung transplant during the 5-year study. METHODS: The LAM Registry enrolled patients from six clinical centers between August 1998 and October 2001. On entry, patients filled-out questionnaires covering their medical history, symptoms, treatment and quality of life (SF-36 and St. George's Respiratory Questionnaire). Enrollees underwent blood laboratory work and testing for arterial blood gases and pulmonary function. Follow-up was done at 6-month and/or yearly intervals. Diagnoses were confirmed by biopsy or typical clinical presentation plus computerized tomography (CT) findings confirmed by independent expert radiologists. A total of 243 women were enrolled. Of these, 13 (5.3%) had been transplanted at time of entry (Group A), 21 (8.6%) were transplanted during the study (Group B), and 48 (19.8%) were either wait-listed for transplant or underwent evaluation after enrollment during the study period (Group C). The remaining 161 (66.3%) registrants were neither considered for nor listed for transplant during the Registry period (Group D). RESULTS: One-third of patients in a large sample of LAM patients had either been transplanted or were being considered for transplant. At enrollment, patients who had already been transplanted and those not in need of transplant (Groups A and D) had better pulmonary function and quality-of-life scores compared with patients who subsequently underwent lung transplant during the Registry period (Group B). CONCLUSIONS: In this large Registry of LAM patients, lung transplantation appears to be associated both with significantly improved lung function and quality of life compared with patients with advanced disease. (+info)