Decline in lung function in lymphangioleiomyomatosis: relation to menopause and progesterone treatment

EPIDEMIOLOGY, PATHOGENESIS and DIAGNOSIS of LYMPHANGIOLEIOMYOMATOSIS

INTRODUCTION

Lymphangioleiomyomatosis (LAM) is a disease of women characterized by cystic lung destruction, lymphatic involvement, and renal angiomyolipomas.

AREAS COVERED

LAM is caused by proliferation of abnormal smooth muscle-like LAM cells containing mutations and perhaps epigenetic modifications of the TSC1 or TSC2 genes, which encode, respectively, hamartin and tuberin, two proteins controlling the mechanistic target of rapamycin (mTOR) signaling pathway. LAM occurs sporadically or in association with tuberous sclerosis complex. LAM may present with dyspnea, recurrent pneumothorax or chylothorax. Pulmonary function tests show reduced flow rates and lung diffusion capacity. Exercise testing may reveal hypoxemia and ventilatory limitation. The severity and progression of disease may be assessed by computer tomography, and pulmonary function and exercise testing. mTOR inhibitors, (e.g., sirolimus) are effective in stabilizing lung function, and reducing the size of chylous effusions, lymphangioleiomyomas, and angiomyolipomas.

EXPERT OPINION

Different clinical phenotypes including variable rates of disease progression and variable responses to therapy are seen in LAM patients. No one test is available that predicts the course of disease at the time of diagnosis. Further research regarding the molecular biology of LAM clinical phenotypes is warranted. Recent advances in the characterization of the pathogenesis of LAM are leading to the development of new therapies.

Reductions in pulmonary function detected in patients with lymphangioleiomyomatosis: An analysis of the Japanese National Research Project on Intractable Diseases database

BACKGROUND

In lymphangioleiomyomatosis (LAM), predicting lung disease progression is essential for treatment planning. However, no previous Japanese studies have attempted to predict the reductions in pulmonary function that occur in LAM patients.

METHODS

The data for 89 LAM patients who had undergone ≥3 spirometry tests and whose data had been registered in the Japanese National Research Project on Intractable Diseases database between October 2009 and March 2014 were analyzed after excluding patients who had undergone (1) a lung transplant; (2) mTOR inhibitor treatment; or (3) thoracic drainage, pleurodesis, surgery, or thoracic duct ligation during the study period. The rates of change (slope) in pulmonary parameters were calculated, and their associations with clinical background factors were investigated.

RESULTS

Among the whole study population, the median (quartiles) slope of forced expiratory volume in one second (FEV1) was -46.7 (-95.2; -15.0)mL per year. Episodes of conservatively treated pneumothorax during the study period were found to be associated with rapid reductions in FEV1 (% predicted). Pregnancy during the study period was associated with a reduction in FEV1 (% predicted). When the patients were divided into those who exhibited initial FEV1 (% predicted) values of >70% (Group A) and ≤70% (Group B), Group B displayed significantly faster reductions in FEV1 (% predicted) than Group A.

CONCLUSIONS

LAM patients whose initial FEV1 (% predicted) values are ≤70% subsequently exhibit rapid reductions in their FEV1 values, and hence, require treatment. However, the FEV1 reduction rate varies markedly among individuals and should be monitored in all cases.

[Pulmonary lymphangioleiomyomatosis: From pathogenesis to management]

INTRODUCTION

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting mainly young women.

BACKGROUND

The respiratory manifestations are characterized by a progressive cystic destruction of the lung parenchyma. Extrapulmonary involvement includes benign renal tumours called angiomyolipomas and abdominal lymphatic masses called lymphangioleiomyomas. At the pathological level, the cellular proliferation found in LAM is in part due to the presence of mutations in the tumour suppressor genes TSC1 and TSC2 (Tuberous Sclerosis Complex). These mutations lead to the activation of the mTOR pathway, which is currently the main therapeutic target. mTOR inhibitors such as sirolimus or everolimus have shown a beneficial effect on the decline in pulmonary function and a reduction of angiomyolipoma size, but are necessary in only some patients.

PERSPECTIVES

LAM cells have migratory properties mediated by the formation of new lymphatic vessels. They are also able to secrete metalloproteases, which enhance their invasiveness. Moreover, the expression of estrogen and progesterone receptors by LAM cells suggests a possible role for sex hormones in the pathogenesis of the disease.

CONCLUSION

A better understanding of mTOR-independent mechanisms would allow the development of novel therapeutic approaches.

The changing face of a rare disease: lymphangioleiomyomatosis

Lymphangioleiomyomatosis is a rare disease characterised by cystic destruction of the lung, lymphatic abnormalities and abdominal tumours. It affects almost exclusively females and can occur sporadically or in patients with tuberous sclerosis complex. In the past decade remarkable progress has been made in understanding of the pathogenesis of this disease leading to a new therapeutic approach. This review summarises recent advances regarding pathogenic mechanisms and clinical manifestations, and highlights the current and the most promising future therapeutic strategies.

Diffuse Cystic Lung Disease. Part I

The diffuse cystic lung diseases (DCLDs) are a group of pathophysiologically heterogenous processes that are characterized by the presence of multiple spherical or irregularly shaped, thin-walled, air-filled spaces within the pulmonary parenchyma. Although the mechanisms of cyst formation remain incompletely defined for all DCLDs, in most cases lung remodeling associated with inflammatory or infiltrative processes results in displacement, destruction, or replacement of alveolar septa, distal airways, and small vessels within the secondary lobules of the lung. The DCLDs can be broadly classified according to underlying etiology as those caused by low-grade or high-grade metastasizing neoplasms, polyclonal or monoclonal lymphoproliferative disorders, infections, interstitial lung diseases, smoking, and congenital or developmental defects. In the first of a two-part series, we present an overview of the cystic lung diseases caused by neoplasms, infections, smoking-related diseases, and interstitial lung diseases, with a focus on lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis.

Everolimus for the treatment of lymphangioleiomyomatosis: a phase II study

Lymphangioleiomyomatosis is a rare, progressive cystic lung disorder characterised by dysregulated activation of mammalian target of rapamycin (mTOR) signalling.

This was a phase IIa, multicentre, open-label study of the mTOR inhibitor everolimus (2.5 mg·day−1 escalated to 10 mg·day−1) in 24 women with lymphangioleiomyomatosis. Primary endpoints were safety, pharmacokinetics and serum vascular endothelial growth factor-D (VEGF-D) levels; secondary endpoints were measures of lung function.

Following 26 weeks of everolimus treatment, forced vital capacity exhibited stability, while forced expiration volume in 1 s improved from baseline, with mean changes (95% confidence interval) of 10 mL (−111–132) and 114 mL (11–217), respectively; 6-min walk distance improved by 47 m. Median VEGF-D and collagen IV levels decreased from baseline, from 1730 pg·mL−1 to 934.5 pg·mL−1, and 103 ng·mL−1 to 80.5 ng·mL−1, respectively. Adverse events were mostly grade 1−2; mouth ulceration, headache, nausea, stomatitis and fatigue were common. Serious adverse events suspected to be treatment related included peripheral oedema, pneumonia, cardiac failure and Pneumocystis jirovecii infection. Everolimus blood levels increased dose proportionally.

In this study, everolimus improved some measures of lung function and exercise capacity and reduced serum VEGF-D and collagen IV. Side effects were generally consistent with known toxicities of mTOR inhibitors, although some were severe.

Lymphangioleiomyomatosis: New Treatment Perspectives

Lymphangioleiomyomatosis (LAM) is a rare multisystem disease, occurs in women, usually premenopausal, caused by the proliferation of neoplastic smooth muscle-derived cells. Mutations in the tuberous sclerosis complex genes, lead to the activation of mammalian target of rapamycin kinase (mTOR), results in proliferation of LAM cells, its increasing motility, and survival. Polycystic lung destruction, extensive involvement of lymphatic channels, chylothorax, chyloperitoneum, and renal angiomyolipomas can develop in LAM patients. The new, promising treatment strategies have been recently introduced due to discovery of the genetic and molecular mechanisms of LAM. Comprehension of the disease pathogenesis has resulted in the implementation of other therapeutic agents such as mTOR inhibitors, VEGF-D inhibitors, statins, interferon, chloroquine analogs, cyclin-dependent kinase inhibitors, matrix metalloproteinase inhibitors, aromatase inhibitors, and their combinations. The mTOR inhibitors appear to be the most important, and the efficacy of sirolimus in LAM treatment has been proved. The article discussed the new control studies with mTOR inhibitors, doxycycline, simvastatin, and combination of them in LAM patients.

Clinical features, epidemiology, and therapy of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a multisystem disease of women, characterized by proliferation of abnormal smooth muscle-like LAM cells, leading to the formation of lung cysts, fluid-filled cystic structures in the axial lymphatics (eg, lymphangioleiomyomas), and renal angiomyolipomas. LAM is caused by mutations of the TSC1 or TSC2 genes, which encode, respectively, hamartin and tuberin, two proteins with a major role in control of the mammalian target of rapamycin (mTOR) signaling pathway. LAM occurs sporadically or in association with tuberous sclerosis complex, an autosomal-dominant syndrome characterized by widespread hamartomatous lesions. LAM may present with progressive dyspnea, recurrent pneumothorax, or chylothorax. Pulmonary function tests show reduced flow rates (forced expiratory volume in the first second) and diffusion capacity. Exercise testing may reveal gas exchange abnormalities, ventilatory limitation, and hypoxemia. The severity and progression of disease may be assessed by lung histology scores, quantification of computed tomography, pulmonary function testing, 6-minute walk tests, cardiopulmonary exercise testing, and measurement of serum vascular endothelial growth factor D levels. Sirolimus and everolimus, two mTOR inhibitors, are effective in stabilizing lung function and reducing the size of chylous effusions, lymphangioleiomyo-mas, and angiomyolipomas. However, inhibition of mTOR complex 1 increases autophagy, possibly enhancing LAM cell survival. Inhibition of autophagy with hydroxychloroquine, in combination with sirolimus, has been proposed as a possible treatment for LAM. Deficiency of tuberin results in increased RhoA GTPase activity and cell survival, an effect that is mediated through mTOR complex 2 signaling. Because sirolimus and everolimus only affect the activity of mTOR complex 1, therapies targeting RhoA GTPases with simvastatin, which inhibits Rho GTPases and promotes apoptosis, are being investigated. As in the case of cancer, LAM may be best treated with multiple drugs targeting signaling pathways considered important in the pathogenesis of disease.

Primary abdominal lymphangioleiomyomatosis: report of a case

Lymphangioleiomyomatosis is an uncommon progressive disease characterized by hamartomatous smooth muscle proliferation of the airways within the lungs as well as the lymph nodes, lymphatics, and blood vessels of the lungs, mediastinum, and abdomen. The most common manifestations of lymphangioleiomyomatosis are pulmonary symptoms. Primary abdominal lymphangioleiomyomatosis without any pathological changes in the respiratory system is extremely unusual. We report a case of primary abdominal lymphangioleiomyomatosis located between the left hepatic and gastric antrum of a 29-year-old woman. The patient had no typical symptoms of lymphangioleiomyomatosis (dyspnea, pneumothorax) or abdominal pain. All physical examination findings were normal. Laboratory test results, including routine blood examination, liver and kidney function, tumor markers, blood coagulation function, and urine and stool examinations, were all normal. She found abdominal cyst in an annual medical examination by ultrasonography and confirmed by computed tomography. For a clear diagnosis, a laparoscopic abdominal mass resection was performed. The postoperative pathohistological examination findings allowed for the definitive diagnosis. This case report may advance the understanding of primary peritoneal lymphatic leiomyoma and reduce the number of mistakenly diagnosed patients.

Management of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM), a multisystem disease affecting almost exclusively women, is characterized by cystic lung destruction and presents with dyspnea, recurrent pneumothoraxes, chylous effusions, lymphangioleiomyomas, and angiomyolipomas. It is caused by the proliferation of a cancer-like LAM cell that possesses a mutation in either the tuberous sclerosis complex (TSC)1 or TSC2 genes. This article reviews current therapies and new potential treatments that are currently undergoing investigation. The major development in the treatment of LAM is the discovery of two mammalian target of rapamycin (mTOR) inhibitors, sirolimus and everolimus, as effective drugs. However, inhibition of mTOR increases autophagy, which may lead to enhanced LAM cell survival. Use of autophagy inhibitors, for example, hydroxychloroquine, in combination with sirolimus is now the subject of an ongoing drug trial (SAIL trial). Another consequence of mTOR inhibition by sirolimus is an increase in Rho activity, resulting in reduced programmed cell death. From these data, the concept evolved that a combination of sirolimus with disruption of Rho activity with statins (e.g. simvastatin) may increase TSC-null cell death and reduce LAM cell survival. A combined trial of sirolimus with simvastatin is under investigation (SOS trial). Since LAM occurs primarily in women and TSC-null cell survival and tumor growth is promoted by estrogens, the inhibition of aromatase to block estrogen synthesis is currently undergoing study (TRAIL trial). Other targets, for example, estrogen receptors, mitogen-activated protein kinase inhibitors, vascular endothelial growth factor-D signaling pathway, and Src kinase, are also being studied in experimental model systems. As in the case of cancer, combination therapy may become the treatment of choice for LAM.

Progesterone and estradiol synergistically promote the lung metastasis of tuberin-deficient cells in a preclinical model of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a female-predominant lung disease that can lead to respiratory failure. LAM cells typically have inactivating tuberous sclerosis 2 (TSC2) mutations, leading to mTORC1 hyperactivation. The gender specificity of LAM suggests that female hormones contribute to disease progression. Clinical findings indicate that estradiol exacerbates LAM behaviors and symptoms. Although hormonal therapy with progesterone has been employed, the benefit in LAM improvement has not been achieved. We have previously found that estradiol promotes the survival and lung metastasis of cells lacking tuberin in a preclinical model of LAM. In this study, we hypothesize that progesterone alone or in combination with estradiol promotes metastatic behaviors of TSC2-deficient cells. In cell culture models of TSC2-deficient LAM patient-derived and rat uterine leiomyoma-derived cells, we found that progesterone treatment or progesterone plus estradiol resulted in increased phosphorylation of Protein Kinase B (Akt) and Extracellular signal-regulated kinases1/2 (ERK1/2), induced the proliferation, and enhanced the migration and invasiveness. In addition, treatment of progesterone plus estradiol synergistically decreased the levels of reactive oxygen species and enhanced cell survival under oxidative stress. In a murine model of LAM, treatment of progesterone plus estradiol promoted the growth of xenograft tumors; however, progesterone treatment did not affect the development of xenograft tumors of Tsc2-deficient cells. Importantly, treatment of progesterone plus estradiol resulted in alteration of lung morphology and significantly increased the number of lung micrometastases of Tsc2-deficient cells compared with estradiol treatment alone. Collectively, these data indicate that progesterone increases the metastatic potential of Tsc2-deficient LAM patient-derived cells in vitro and lung metastasis in vivo. Thus, targeting progesterone-mediated signaling events may have therapeutic benefit for LAM and possibly other hormonally dependent cancers.

"Getting stuck with LAM": patients perspectives on living with lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease that affects almost exclusively women and is most often diagnosed before menopause. The main symptom of LAM is shortness of breath. LAM patients' perceptions of how the disease impacts their lives is largely unknown, but such information could be useful to generate patient reported outcome measures for use in drug trials (or other research studies) and to formulate interventions aimed at easing the burdens LAM imposes on patients.

OBJECTIVE

To capture patients' perceptions of how LAM affects their lives.

METHODS

We used reflexive team analysis to analyze transcripts from semi-structured focus groups conducted with LAM patients at LAMposium 2013. We sought to determine what patients perceive as the primary symptoms of LAM and how the disease affects them in their daily lives.

RESULTS

The 37 participants described seven primary symptoms of LAM and five common psychological experiences from living with the disease. Shortness of breath and low energy (or fatigue) dominated the symptomatic picture; cough, sensations in the chest, difficulty sleeping, gastrointestinal issues, and mild cognitive difficulties were less common. The common psychological experiences participants reported included frustration, worry, loss of identity, embarrassment, and in some participants, a healthy defiance against the disease.

CONCLUSIONS

Patients perceive the physical symptoms from LAM to be intrusive and limiting. Women living with LAM are frustrated by their physical limitations, and they worry about what the future will be like if the disease progresses. Therapeutic interventions should take aim at improving these perceptions.

Palliative management of lymphangioleiomyomatosis: Using video-assisted thoracoscopic surgery

Lymphangioleiomyomatosis (LAM) is a rare, progressive systemic disease of unknown etiology, insidious onset, often fatal, and underdiagnosed. It is exclusively found among women. LAM mainly involves the lungs where, as its name suggests, lymphatic (lymph), blood vessel (angio), and airways are surrounded by smooth muscle (leiomyoma) proliferation. It may be associated with tuberous sclerosis with clinical manifestations varying from simple cough to the development of recurrent pneumothoraces, haemoptysis, and pleural effusions. There is currently no treatment or cure. We present a rare case of a 41-year-old female, who presented with recurrent pneumothoraces, whose high-resolution computed tomography findings that were suggestive of multiple bullous lung disease, and the thoracoscopic biopsy revealed features of LAM. She was offered video-assisted thoracoscopic surgery in form of bullectomy and pleurodesis to reduce the volume of abnormal tissue and treated with progesterone hormonal therapy. The present case aims to focus on clinical-radiologic and pathologic findings and the treatment modalities available in developing countries like India where lung transplantation is seldom performed.

Doxycycline use in patients with lymphangioleiomyomatosis: biomarkers and pulmonary function response

OBJECTIVE

To assess blockade of matrix metalloproteinase (MMP)-2 and MMP-9, as well as the variation in FEV1, in patients with lymphangioleiomyomatosis (LAM) treated with doxycycline (a known MMP inhibitor) for 12 months.

METHODS

An open-label, single-arm, interventional clinical trial in which LAM patients received doxycycline (100 mg/day) for 12 months. Patients underwent full pulmonary function testing, a six-minute walk test, and quality of life assessment, as well as blood and urine sampling for quantification of MMP-2, MMP-9, and VEGF-D levels-at baseline, as well as at 6 and 12 months after the initiation of doxycycline.

RESULTS

Thirty-one LAM patients received doxycycline for 12 months. Although there was effective blockade of urinary MMP-9 and serum MMP-2 after treatment, there were no significant differences between pre- and post-doxycycline serum levels of MMP-9 and VEGF-D. On the basis of their response to doxycycline (as determined by the variation in FEV1), the patients were divided into two groups: the doxycycline-responder (doxy-R) group (n = 13); and the doxycycline-nonresponder (doxy-NR) group (n = 18). The patients with mild spirometric abnormalities responded better to doxycycline. The most common side effects were mild epigastric pain, nausea, and diarrhea.

CONCLUSIONS

In patients with LAM, doxycycline treatment results in effective MMP blockade, as well as in improved lung function and quality of life in those with less severe disease. However, these benefits do not seem to be related to the MMP blockade, raising the hypothesis that there is a different mechanism of action. (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-6g8yz9 [http://www.ensaiosclinicos.gov.br]).

St. George's Respiratory Questionnaire has longitudinal construct validity in lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is an uncommon, progressive, cystic lung disease that causes shortness of breath, hypoxemia, and impaired health-related quality of life (HRQL). Whether St. George's Respiratory Questionnaire (SGRQ), a respiratory-specific HRQL instrument, captures longitudinal changes in HRQL in patients with LAM is unknown.

METHODS

Using data from the Multicenter International Lymphangioleiomyomatosis Efficacy and Safety of Sirolimus trial, we performed analyses to examine associations between SGRQ scores and values for four external measures (anchors). Anchors included (1) FEV₁, (2) diffusing capacity of the lung for carbon monoxide, (3) distance walked during the 6-min walk test, and (4) serum vascular endothelial growth factor-D.

RESULTS

SGRQ scores correlated with the majority of anchor values at baseline, 6 months, and 12 months. Results from longitudinal analyses demonstrated that SGRQ change scores tracked changes over time in values for each of the four anchors. At 12 months, subjects with the greatest improvement from baseline in FEV₁ experienced the greatest improvement in SGRQ scores (Symptoms domain, -13.4 ± 14.6 points; Activity domain, -6.46 ± 8.20 points; Impacts domain, -6.25 ± 12.8 points; SGRQ total, -7.53 ± 10.0 points). Plots of cumulative distribution functions further supported the longitudinal validity of the SGRQ in LAM.

CONCLUSIONS

In LAM, SGRQ scores are associated with variables used to assess LAM severity. The SGRQ is sensitive to change in LAM severity, particularly when change is defined by FEV₁, perhaps the most clinically relevant and prognostically important variable in LAM. The constellation of results here supports the validity of the SGRQ as capable of assessing longitudinal change in HRQL in LAM.

Uterine-specific loss of Tsc2 leads to myometrial tumors in both the uterus and lungs

Lymphangioleiomyomatosis (LAM) is a rare disease characterized by proliferation of abnormal smooth-muscle cells in the lungs, leading to functional loss and sometimes lung transplantation. Although the origin of LAM cells is unknown, several features of LAM provide clues. First, LAM cells contain inactivating mutations in genes encoding Tsc1 or Tsc2, proteins that limit mTORC1 activity. Second, LAM tumors recur after lung transplantation, suggesting a metastatic pathogenesis. Third, LAM is found almost exclusively in women. Finally, LAM shares features with uterine leiomyomas, benign tumors of myometrial cells. From these observations, we proposed that LAM cells might originate from uterine leiomyomas containing Tsc mutations. To test our hypothesis, and to develop mouse models for leiomyoma and LAM, we targeted Tsc2 deletion primarily in uterine cells. In fact, nearly 100% of uteri from uterine-specific Tsc2 knockout mice developed myometrial proliferation and uterine leiomyomas by 12 and 24 weeks, respectively. Myometrial proliferation and mTORC1/S6 activity were abrogated by the mTORC1 inhibitor rapamycin or by elimination of sex steroid production through ovariectomy or aromatase inhibition. In ovariectomized Tsc2 null mice, mTORC1/S6 activity and myometrial growth were restored by estrogen but not progesterone. Thus, even without Tsc2, estrogen appears to be required for myometrial mTORC1/S6 signaling and proliferation. Finally, we found Tsc2 null myometrial tumors in lungs of older Tsc2 uterine-specific knockout females, suggesting that lung LAM-like myometrial lesions may indeed originate from the uterus. This mouse model may improve our understanding of LAM and leiomyomas and might lead to novel therapeutic strategies for both diseases.

Lymphatics in lymphangioleiomyomatosis and idiopathic pulmonary fibrosis

The primary function of the lymphatic system is absorbing and transporting macromolecules and immune cells to the general circulation, thereby regulating fluid, nutrient absorption and immune cell trafficking. Lymphangiogenesis plays an important role in tissue inflammation and tumour cell dissemination. Lymphatic involvement is seen in lymphangioleiomyomatosis (LAM) and idiopathic pulmonary fibrosis (IPF). LAM, a disease primarily affecting females, involves the lung (cystic destruction), kidney (angiomyolipoma) and axial lymphatics (adenopathy and lymphangioleiomyoma). LAM occurs sporadically or in association with tuberous sclerosis complex (TSC). Cystic lung destruction results from proliferation of LAM cells, which are abnormal smooth muscle-like cells with mutations in the TSC1 or TSC2 gene. Lymphatic abnormalities arise from infiltration of LAM cells into the lymphatic wall, leading to damage or obstruction of lymphatic vessels. Benign appearing LAM cells possess metastatic properties and are found in the blood and other body fluids. IPF is a progressive lung disease resulting from fibroblast proliferation and collagen deposition. Lymphangiogenesis is associated with pulmonary destruction and disease severity. A macrophage subset isolated from IPF bronchoalveolar lavage fluid (BALF) express lymphatic endothelial cell markers in vitro, in contrast to the same macrophage subset from normal BALF. Herein, we review lymphatic involvement in LAM and IPF.

Targeted approaches toward understanding and treating pulmonary lymphangioleiomyomatosis (LAM)

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease found almost exclusively in women that is characterized by neoplastic growth of atypical smooth muscle-like cells in the lung, destruction of lung parenchyma, and obstruction of lymphatics. These processes lead to the formation of lung cysts, rupture of which results in spontaneous pneumothorax. Progression of LAM often results in loss of pulmonary function and death. LAM affects predominantly women of childbearing age and is exacerbated by pregnancy. The only proven treatment for LAM is lung transplantation, and even then LAM cells will often return to the transplanted lung. However, methodical and targeted approaches toward understanding LAM pathophysiology have led to the discovery of new potential therapeutic avenues. For example, the mutational inactivation of tumor suppressor complex genes tuberous sclerosis complex 1 or tuberous sclerosis complex 2 has been shown to be present in lung LAM cells. These mutations occur sporadically or in association with inherited hamartoma syndrome tuberous sclerosis (TSC). Since TSC genes function as negative regulators of the mammalian target of rapamycin, a major controller of cell growth, metabolism, and survival, rapamycin analogs have recently been used to treat LAM patients with promising results. Similarly, studies focusing on the importance of estrogen in LAM progression have suggested that anti-estrogen therapy might prove to be an alternative means of treating LAM. This minireview summarizes recent progress in understanding LAM pathophysiology, including the latest preclinical and clinical studies, and insights regarding the role of hormones in LAM.

Lymphangioleiomyomatosis - a wolf in sheep's clothing

Lymphangioleiomyomatosis (LAM) is a rare progressive lung disease of women. LAM is caused by mutations in the tuberous sclerosis genes, resulting in activation of the mTOR complex 1 signaling network. Over the past 11 years, there has been remarkable progress in the understanding of LAM and rapid translation of this knowledge to an effective therapy. LAM pathogenic mechanisms mirror those of many forms of human cancer, including mutation, metabolic reprogramming, inappropriate growth and survival, metastasis via blood and lymphatic circulation, infiltration/invasion, sex steroid sensitivity, and local and remote tissue destruction. However, the smooth muscle cell that metastasizes, infiltrates, and destroys the lung in LAM arises from an unknown source and has an innocent histological appearance, with little evidence of proliferation. Thus, LAM is as an elegant, monogenic model of neoplasia, defying categorization as either benign or malignant.

Clinical utility of diagnostic guidelines and putative biomarkers in lymphangioleiomyomatosis

Background

Lymphangioleiomyomatosis is a rare disease occurring almost exclusively in women. Diagnosis often requires surgical biopsy and the clinical course varies between patients with no predictors of progression. We evaluated recent diagnostic guidelines, clinical features and serum biomarkers as diagnostic and prognostic tools.

Methods

Serum vascular endothelial growth factor-D (VEGF-D), angiotensin converting enzyme (ACE), matrix metalloproteinases (MMP) -2 and -9, clinical phenotype, thoracic and abdominal computerised tomography, lung function and quality of life were examined in a cohort of 58 patients. 32 healthy female controls had serum biomarkers measured.

Results

Serum VEGF-D, ACE and total MMP-2 levels were elevated in patients. VEGF-D was the strongest discriminator between patients and controls (median = 1174 vs. 332 pg/ml p < 0.0001 with an area under the receiver operating characteristic curve of 0.967, 95% CI 0.93-1.01). Application of European Respiratory Society criteria allowed a definite diagnosis without biopsy in 69%. Adding VEGF-D measurement to ERS criteria further reduced the need for biopsy by 10%. VEGF-D was associated with lymphatic involvement (p = 0.017) but not the presence of angiomyolipomas.

Conclusions

Combining ERS criteria and serum VEGF-D reduces the need for lung biopsy in LAM. VEGF-D was associated with lymphatic disease but not lung function.

Multicenter phase 2 trial of sirolimus for tuberous sclerosis: kidney angiomyolipomas and other tumors regress and VEGF- D levels decrease

BACKGROUND

Tuberous sclerosis (TSC) related tumors are characterized by constitutively activated mTOR signaling due to mutations in TSC1 or TSC2.

METHODS

We completed a phase 2 multicenter trial to evaluate the efficacy and tolerability of the mTOR inhibitor, sirolimus, for the treatment of kidney angiomyolipomas.

RESULTS

36 adults with TSC or TSC/LAM were enrolled and started on daily sirolimus. The overall response rate was 44.4% (95% confidence intervals [CI] 28 to 61); 16/36 had a partial response. The remainder had stable disease (47.2%, 17/36), or were unevaluable (8.3%, 3/36). The mean decrease in kidney tumor size (sum of the longest diameters [sum LD]) was 29.9% (95% CI, 22 to 37; n = 28 at week 52). Drug related grade 1-2 toxicities that occurred with a frequency of >20% included: stomatitis, hypertriglyceridemia, hypercholesterolemia, bone marrow suppression (anemia, mild neutropenia, leucopenia), proteinuria, and joint pain. There were three drug related grade 3 events: lymphopenia, headache, weight gain. Kidney angiomyolipomas regrew when sirolimus was discontinued but responses tended to persist if treatment was continued after week 52. We observed regression of brain tumors (SEGAs) in 7/11 cases (26% mean decrease in diameter), regression of liver angiomyolipomas in 4/5 cases (32.1% mean decrease in longest diameter), subjective improvement in facial angiofibromas in 57%, and stable lung function in women with TSC/LAM (n = 15). A correlative biomarker study showed that serum VEGF-D levels are elevated at baseline, decrease with sirolimus treatment, and correlate with kidney angiomyolipoma size (Spearman correlation coefficient 0.54, p = 0.001, at baseline).

CONCLUSIONS

Sirolimus treatment for 52 weeks induced regression of kidney angiomyolipomas, SEGAs, and liver angiomyolipomas. Serum VEGF-D may be a useful biomarker for monitoring kidney angiomyolipoma size. Future studies are needed to determine benefits and risks of longer duration treatment in adults and children with TSC.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00126672.

Evolução da função pulmonar após tratamento com goserelina em pacientes com linfangioleiomiomatose

Nas células musculares lisas atípicas características da linfangioleiomiomatose (LAM) encontram-se receptores de estrogênio e progesterona, de modo que o tratamento anti-hormonal pode ser considerado uma opção, mas ainda com resultados controversos. O objetivo deste trabalho foi avaliar retrospectivamente parâmetros hormonais e espirométricos em nove mulheres com LAM após o tratamento com goserelina por um ano. Houve um aumento médio de 80 mL e 130 mL, respectivamente, em VEF1 e CVF, assim como bloqueio hormonal efetivo. Ainda não se pode excluir um potencial efeito favorável da utilização de análogos de hormônio liberador de gonadotrofina em pacientes com LAM, reforçando a necessidade de ensaios randomizados

Efficacy and safety of sirolimus in lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a progressive, cystic lung disease in women; it is associated with inappropriate activation of mammalian target of rapamycin (mTOR) signaling, which regulates cellular growth and lymphangiogenesis. Sirolimus (also called rapamycin) inhibits mTOR and has shown promise in phase 1-2 trials involving patients with LAM.

METHODS

We conducted a two-stage trial of sirolimus involving 89 patients with LAM who had moderate lung impairment--a 12-month randomized, double-blind comparison of sirolimus with placebo, followed by a 12-month observation period. The primary end point was the difference between the groups in the rate of change (slope) in forced expiratory volume in 1 second (FEV(1)).

RESULTS

During the treatment period, the FEV(1) slope was -12±2 ml per month in the placebo group (43 patients) and 1±2 ml per month in the sirolimus group (46 patients) (P<0.001). The absolute between-group difference in the mean change in FEV(1) during the treatment period was 153 ml, or approximately 11% of the mean FEV(1) at enrollment. As compared with the placebo group, the sirolimus group had improvement from baseline to 12 months in measures of forced vital capacity, functional residual capacity, serum vascular endothelial growth factor D (VEGF-D), and quality of life and functional performance. There was no significant between-group difference in this interval in the change in 6-minute walk distance or diffusing capacity of the lung for carbon monoxide. After discontinuation of sirolimus, the decline in lung function resumed in the sirolimus group and paralleled that in the placebo group. Adverse events were more common with sirolimus, but the frequency of serious adverse events did not differ significantly between the groups.

CONCLUSIONS

In patients with LAM, sirolimus stabilized lung function, reduced serum VEGF-D levels, and was associated with a reduction in symptoms and improvement in quality of life. Therapy with sirolimus may be useful in selected patients with LAM. (Funded by the National Institutes of Health and others; MILES ClinicalTrials.gov number, NCT00414648.).

Lymphangioleiomyomatosis: what do we know and what are we looking for?

Lymphangioleiomyomatosis (LAM) is a rare disease characterised by proliferation of abnormal smooth muscle-like cells (LAM cells) leading to progressive cystic destruction of the lung, lymphatic abnormalities and abdominal tumours. It affects predominantly females and can occur sporadically or in patients with tuberous sclerosis complex. This review describes the recent progress in our understanding of the molecular pathogenesis of the disease and LAM cell biology. It also summarises current therapeutic approaches and the most promising areas of research for future therapeutic strategies.

Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disease that mainly affects women, particularly at fertile age. It is sporadic or associated with tuberous sclerosis complex. It is characterised by an abnormal proliferation of immature smooth muscle cells (SMC), which grow aberrantly in the airway, parenchyma, lymphatics and pulmonary blood vessels and which can gradually lead to respiratory failure. It affects several systems, affecting the lymphatic ganglia and causing abdominal tumours. Given its very low prevalence, a difficult to establish early diagnosis, absence of curative treatment and the difficulty in obtaining information, places LAM under the heading of the so-called Rare Diseases. There is a growing interest in the study of this disease which has led to the setting up of patient registers and an exponential growth in LAM research, both at a clinical level and cellular level.

Lymphangioleiomyomatosis (LAM): molecular insights lead to targeted therapies

LAM is a rare lung disease, found primarily in women of childbearing age, characterized by cystic lung destruction and abdominal tumors (e.g., renal angiomyolipoma, lymphangioleiomyoma). The disease results from proliferation of a neoplastic cell, termed the LAM cell, which has mutations in either of the tuberous sclerosis complex (TSC) 1 or TSC2 genes. Molecular phenotyping of LAM patients resulted in the identification of therapeutic targets for drug trials. Loss of TSC gene function leads to activation of mammalian target of rapamycin (mTOR), and thereby, effects on cell size and number. The involvement of mTOR in LAM pathogenesis is the basis for initiation of therapeutic trials of mTOR inhibitors (e.g., sirolimus). Occurrence of LAM essentially entirely in women is consistent with the hypothesis that anti-estrogen agents might prevent disease progression (e.g., gonadotropin-releasing hormone analogues). Levels of urinary matrix metalloproteinases (MMPs) were elevated in LAM patients, and MMPs were found in LAM lung nodules. In part because of these observations, effects of doxycycline, an anti-MMP, and anti-angiogenic agent, are under investigation. The metastatic properties of LAM cells offer additional potential for targets. Thus, insights into the molecular and biological properties of LAM cells and molecular phenotyping of patients with LAM have led to clinical trials of targeted therapies. Funded by the Intramural Research Program, NIH/NHLBI.

Effect of doxycycline on proliferation, MMP production, and adhesion in LAM-related cells

Matrix metalloproteinases (MMPs) have been implicated in lung cyst formation in lymphangioleiomyomatosis (LAM). As doxycycline inhibits MMP activity in vivo, some patients take doxycycline, as one report has suggested a possible benefit in LAM. However, there have been no randomized controlled clinical trials of doxycycline for LAM, and any mechanism of action is unclear. Here, we examine previously proposed mechanisms of actions. Cell proliferation and adhesion were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and Cytomatrix cell adhesion kits. Apoptosis was examined by TdT-mediated dUTP nick end labeling (TUNEL) assay. MMP-2 expression was examined by quantitative real-time PCR and zymography in doxycycline-treated ELT3 cells and tumor growth using angiomyolipoma-derived tumor xenografts in nude mice. In ELT3 cells, >or=25 microg/ml doxycycline decreased proliferation, increased apoptosis, and caused a change in cell morphology associated with redistribution of actin stress filaments. Reduction in proliferation was also seen in human angiomyolipoma-derived cells. Cell adhesion to ECM proteins was decreased by doxycycline at 50 microg/ml and prevented detachment of already adherent cells. There was no effect of doxycycline on MMP-2 expression or activity in vitro. In the xenograft model, doxycycline (30 mg*kg(-1)*day(-1)) had no effect on tumor growth, final tumor weight, or tumor lysate MMP levels. Doxycycline at doses >or= 25 microg/ml inhibited cell proliferation and adhesion, possibly by a toxic effect. Doxycycline had no effect on MMP-2 expression or activity or tumor growth in the xenograft model. Any possible in vivo effect is unlikely to be mediated by MMP-2 or reduced cell proliferation.

Clinical analysis of patients with pulmonary lymphangioleiomyomatosis (PLAM) in mainland China

BACKGROUND AND OBJECTIVE

There have been no clinical reports on pulmonary lymphangioleiomyomatosis (PLAM) based on large studies or epidemiological surveys in mainland China. The purpose of this study was to provide a retrospective analysis of PLAM patients in mainland China by reviewing the clinical data of PLAM cases reported.

METHODS

The China Academic Journals Full-text Database search engine was used to collect related cases in mainland China through the end of 2008. 120 cases met the study's inclusion criteria and were reviewed for this analysis.

RESULTS

The average age of the 120 patients upon confirmed diagnosis was 37.3+/-6.4 years. The average duration from onset of symptoms to a confirmed diagnosis was 29.6+/-35.8 months, with 80 person-time patients having experienced misdiagnosis before the confirmed diagnosis. The major clinical manifestations of PLAM included progressive dyspnea, recurrent pneumatothorax, refractory chylothorax. Pulmonary function abnormalities included obstructive pulmonary ventilation disorders and degenerated diffusing capacity. Ten patients were found to be complicated with renal angiomyolipoma and 17 with abdominal or pelvic lymphangioleiomyoma. Half of the patients had undergone antiestrogen therapies such as progesterone, and four patients received pulmonary transplantation. The average duration from the confirmed diagnosis to death was 36.4+/-48.9 months among the 28 cases of death.

CONCLUSIONS

Doctors in mainland China are becoming increasingly vigilant to PLAM, although misdiagnosis or missed diagnosis still exists. Provider attention to the correlation between PLAM and tuberous sclerosis complex, as well as to the possible involvement of multiple organs, is insufficient.

Pregnancy experiences among women with lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare lung disease affecting women. Following case reports that pregnancy exacerbates LAM, patients are frequently advised to avoid pregnancy. Our objective was to determine pregnancy and health outcomes in LAM to provide better evidence with which to council patients contemplating pregnancy. We surveyed 328 women with LAM regarding pregnancy outcomes, pulmonary function, subjective and psychological functioning, quality of life, dyspnoea and fatigue. Amongst childless women the main reason not to attempt pregnancy was based on concerns about potential effects of pregnancy on LAM. Almost two thirds of patients had been pregnant, the majority before LAM was diagnosed, in whom pregnancy outcome was generally favourable. Women diagnosed with LAM (n=15) during pregnancy had high rates of pneumothorax (67%), miscarriage (7%) and premature birth (47%). The group diagnosed with LAM before or during pregnancy (n=12) had lower mean FEV(1), FVC and DLCO after pregnancy compared with those diagnosed following pregnancy or never pregnant. There were no differences in subjective or psychological functioning, quality of life, dyspnoea or fatigue scores between groups. In newly diagnosed LAM patients there was a high incidence of premature birth and pneumothorax. These adverse outcomes may be a marker of aggressive LAM.

Lymphangioleiomyomatosis and tuberous sclerosis complex

Lymphangioleiomyomatosis (LAM) is a rare multisystemic disease of women of child-bearing age and affects mainly the lungs, promoting cystic destruction of lung parenchyma or leading to abdominal tumor formation (e.g., angiomyolipomas, lymphangioleiomyomas). LAM can arise sporadically or in association with tuberous sclerosis complex (TSC), an autosomal inherited syndrome characterized by hamartoma-like tumor growth and pathologic features that are distinct from manifestations of pulmonary LAM. A substantial body of evidence has now been gathered suggesting that the two diseases share a common genetic origin. TSC is caused by mutations in two genes, TSC1 on chromosome 9q34 and TSC2 on 16p13. Both of these genes are tumor suppressor genes encoding hamartin (TSC1) and tuberin (TSC2). Sporadic LAM is correlated with a mutation in the TSC2 gene and tuberin appears to play a central role in the pathogenesis of the disease. A TSC2 loss or mutation leads to disruption of the tuberin-hamartin heteromer and dysregulation of S6K1 activation leading to aberrant cell proliferation seen in LAM disease. The extremely diverse clinical and radiologic features of the disease and the complex therapeutic approach are reviewed in detail. Although new therapeutic agents have been tested, to date no effective treatment has been proposed and the prognosis of patients with LAM remains poor. As long as newer therapeutic agents do not change this picture, lung transplantation remains the last hope for patients with respiratory failure at the advanced stage of the disease.

Effect of a gonadotrophin-releasing hormone analogue on lung function in lymphangioleiomyomatosis

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.

The epidemiology of lymphangioleiomyomatosis in Japan: a nationwide cross-sectional study of presenting features and prognostic factors

BACKGROUND AND OBJECTIVE

To evaluate the characteristics and prognostic factors of Japanese patients with lymphangioleiomyomatosis (LAM).

METHODS

A nationwide survey to identify patients with LAM was conducted by questionnaire. Survival probability was estimated using the Kaplan-Meier method, and the prognostic factors were analysed by Cox regression.

RESULTS

Data were collected on 173 patients with pulmonary LAM. The major presenting features were pneumothorax (43%) and exertional dyspnoea (37%). The survival probabilities for patients presenting with exertional dyspnoea (Group A) were 85%, 60% and 47% after 5, 10 and 15 years, respectively, and for patients presenting with pneumothorax (Group B) were 95%, 89% and 89%, respectively. Although the age at symptom onset was higher among patients in Group A than in Group B, Cox regression revealed that the presenting feature was a prognostic factor independent of age at symptom onset (Group A/B hazard ratio = 5.732, P < 0.01). In the subgroup of patients whose initial FEV(1) was >1000 mL, or FEV(1)/FVC >40%, or %DL(CO) >40%, the rate of deterioration in these tests was greater in Group A than in Group B (P < 0.01 for FEV(1), P < 0.05 for FEV(1)/FVC and %DL(CO)).

CONCLUSIONS

There are two possible subgroups of LAM patients. One subgroup that presented with pneumothorax, had onset of symptoms at a younger age and a more favourable prognosis; the other presented with exertional dyspnoea, had onset of symptoms at an older age and a poorer prognosis.

Challenges in pulmonary fibrosis. 3: Cystic lung disease

Cystic lung disease is a frequently encountered problem caused by a diverse group of diseases. Distinguishing true cystic lung disease from other entities, such as cavitary lung disease and emphysema, is important given the differing prognostic implications. In this paper the features of the cystic lung diseases are reviewed and contrasted with their mimics, and the clinical and radiographic features of both diffuse (pulmonary Langerhans' cell histiocytosis and lymphangioleiomyomatosis) and focal or multifocal cystic lung disease are discussed.

[Pulmonary lymphangioleiomyomatosis with or without tuberous sclerosis]

INTRODUCTION

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting young women and presenting with recurrent pneumothorax.

BACKGROUND

Other lesions such as chylothorax or renal angiomyolipoma may suggest the diagnosis. The condition is related to a proliferation of abnormal smooth muscle cells staining for the monoclonal antibody HMB45. LAM can appear sporadically or be associated with tuberous sclerosis with abnormalities of the TSC2 suppressor gene. High resolution thoracic CT scanning shows bilateral, thin walled pulmonary cysts. Pulmonary function tests reveal bronchial obstruction and over-inflation with a reduced DLCO being the earliest abnormality.

VIEWPOINT

Although there are non-progressive forms, LAM usually leads to chronic respiratory insufficiency within a few, or ten or so years. In the absence of a controlled clinical trial hormone therapy has not been shown to be effective. Lung transplantation is the last therapeutic resort; recurrences in the transplanted lung have been occasionally reported.

CONCLUSIONS

Analysis of the molecular mechanisms induced by mutations of the TSC2 suppressor gene and the demonstration of the migratory properties of smooth muscle cells, whose origin may be extra-thoracic, reveal new specific antiproliferative therapeutic options.

Lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a rare disease that is characterized by proliferation of abnormal smooth muscle-like cells (LAM cells), which leads to the formation of lung cysts, fluid-filled cystic structures in the axial lymphatics, and abdominal tumors. It primarily affects women.

METHODS

The authors present a review of large series, registries, and protocols to highlight the prevalence, pathology, clinical features, diagnosis, and treatment options for patients with LAM.

RESULTS

LAM commonly presents with progressive breathlessness or with recurrent pneumothorax, chylothorax, or sudden abdominal hemorrhage. Computed tomography (CT) scans show numerous thin-walled cysts throughout the lungs, abdominal angiomyolipomas, and lymphangioleiomyomas. Pulmonary function tests show decreased forced expiratory volume in 1 second (FEV1) and diffusion capacity for carbon monoxide (DLCO). Exercise testing shows gas-exchange abnormalities, ventilatory limitation, and hypoxemia that may occur with near-normal lung function.

CONCLUSIONS

No effective treatment currently exists for this progressive disorder. However, recent progress in cancer and smooth muscle cell biology and a better understanding of the factors regulating angiogenesis and lymphangiogenesis may provide a foundation for the development of new therapeutic strategies.

Vascular endothelial growth factor-D is increased in serum of patients with lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a rare destructive lung disease characterized by an abnormal proliferation of smooth muscle-like cells (LAM cells) in the lung and along the axial lymphatics. LAM demonstrates a heterogeneous clinical course, but there is no serum surrogate marker available for assessing the disease severity or predicting the disease progression. Since the authors have recently demonstrated the extensive LAM-associated lymphangiogenesis and its potential role in progression and metastasis of LAM cells, they hypothesized that serum levels of lymphangiogenic growth factors might be increased in LAM and become a surrogate marker for disease severity.

METHODS AND RESULTS

VEGF-A, VEGF-C, and VEGF-D in serum of 44 patients with LAM were measured by enzyme-linked immunosorbant assay. Only VEGF-D was significantly increased in LAM patients as compared with age- and gender-matched healthy volunteers (n=24) (LAM vs. control, geometric mean 95% CI; 1069.3 pg/mL (809.4 approximately 1412.6) vs. 295.9 pg/mL (262.6 approximately 333.5), p<0.0001). Serum VEGF-D levels negatively correlated with variables of pulmonary function tests, FEV1/FVC (forced expiratory volume in one second/forced vital capacity) (r=-0.365, p<0.05) and %DLco/VA (the percentage of diffusing capacity for carbon monoxide/alveolar volume to the predicted value) (r=-0.560, p<0.001). As expected, the group who received hormone therapy showed more deteriorated pulmonary function with higher serum VEGF-D levels than the group who was just observed without hormone therapy. Immunohistochemical examination of lung specimens demonstrated the positive immunoreactivity of LAM cells for VEGF-D.

CONCLUSION

Serum VEGF-D levels may be a valuable surrogate marker for evaluating the disease severity in LAM.

Pleural disease in lymphangioleiomyomatosis

Pleural disease is a common complication of lymphangioleiomyomatosis (LAM). The incidence and recurrence rates of secondary spontaneous pneumothorax in LAM are the highest among chronic pulmonary disorders. Most patients have at least one pneumothorax before LAM is diagnosed, and pneumothorax is often the sentinel event that leads to the diagnosis. Although early, definitive treatment for recurrent pneumothorax by pleurodesis is recommended, the failure rate for chemical and surgical approaches is high. Chylothorax occurs owing to obstruction of lymphatics by proliferating smooth muscle cells and often requires pleurodesis to control expanding and recurrent effusions. Because of the rarity of the LAM, few data exist on whether the occurrence of pleural complications in LAM accelerates functional decline or portends a worse prognosis.

The prevalence of acute response to bronchodilator in pulmonary lymphangioleiomyomatosis

OBJECTIVE

The objective of this study was to evaluate the prevalence of acute bronchodilator responses in patients who were evaluated for pulmonary lymphangioleiomyomatosis.

METHODOLOGY

This study was a retrospective review of the medical records of 50 patients, who were assessed for lymphangioleiomyomatosis from 1978 to 2002 at Mayo Clinic in Rochester, Minnesota, and Jacksonville, Florida, USA. Each medical record was reviewed for pertinent clinical and pulmonary function test data, including results for lung volume and flow, diffusing capacity and response to bronchodilator.

RESULTS

At initial testing, the mean FEV(1)/FVC ratio for the whole group was 60%; 35 patients (70%) had airflow obstruction; five patients (10%) had only restriction; and 10 (20%) had neither restriction nor obstruction. Three patients (6%) showed a positive response to bronchodilator at initial testing and only one patient showed a positive response at 1 year. Pulmonary function testing at 1-year follow up was available in a subgroup of this cohort (23 patients; 46%), and only one patient (2%) had a positive response to bronchodilator. Although there was a statistically significant decrease in the FEV(1)/FVC ratio (from 64% to 62%; P = 0.02), no other differences were found at 1-year follow up.

CONCLUSIONS

In its advanced state, lymphangioleiomyomatosis produces irreversible airflow obstruction. A positive response to bronchodilator was unusual. Other measures of pulmonary function showed little or no change over a 12-month period.

The NHLBI lymphangioleiomyomatosis registry: characteristics of 230 patients at enrollment

RATIONALE

Pulmonary lymphangioleiomyomatosis is a progressive cystic lung disease that is associated with infiltration of atypical smooth muscle-like cells. Previous descriptions of clinical characteristics of subjects with lymphangioleiomyomatosis have been based on a limited number of patients.

OBJECTIVES

To describe the clinical characteristics of subjects with pulmonary lymphangioleiomyomatosis, both sporadic and tuberous sclerosis-related forms.

METHODS

Over a 3-yr period, from 1998 to 2001, 243 subjects with pulmonary lymphangioleiomyomatosis were enrolled into a national registry; 13 subjects who had already undergone lung transplantation were excluded for the purposes of this report.

MEASUREMENTS AND MAIN RESULTS

All 230 subjects were women, aged 18 to 76 yr (mean +/- SE, 44.5 +/- 0.65 yr). The average age at onset of symptoms was 38.9 +/- 0.73 yr and at diagnosis was 41.0 +/- 0.65 yr. Tuberous sclerosis complex was present in 14.8% of subjects. Pulmonary manifestations, most commonly spontaneous pneumothorax, were the primary events leading to the diagnosis in 86.5% of cases. Nearly 55% of the subjects were being treated with a progesterone derivative. An obstructive pattern on pulmonary function testing was observed in 57.3% of the subjects, whereas 33.9% had normal spirometric results. Women with tuberous sclerosis-related lymphangioleiomyomatosis were younger and had less impaired lung function compared with those with the sporadic form.

CONCLUSIONS

The age range of women afflicted with pulmonary lymphangioleiomyomatosis is broader than previously appreciated and the degree of pulmonary function can be quite variable, with one-third of subjects having normal spirometry at enrollment into this registry.