Pulmonary Capillary Hemangiomatosis With Atypical Endotheliomatosis *

Recombinant human endostatin as a potential anti-angiogenic agent: therapeutic perspective and current status

Angiogenesis is the physiological process that results in the formation of new blood vessels develop from pre-existing vasculature and plays a significant role in several physiological and pathological processes. Inhibiting angiogenesis, a crucial mechanism in the growth and metastasis of cancer, has been proposed as a potential anticancer therapy. Different studies showed the beneficial effects of angiogenesis inhibitors either in patients suffering from different cancers, alone or in combination with conventional therapies. Even though there are currently a number of efficient anti-angiogenic drugs, including monoclonal antibodies and kinase inhibitors, the associated toxicity profile and their affordability constraints are prompting researchers to search for a safe and affordable angiostatic agent for cancer treatment. Endostatin is one of the endogenous anti-angiogenic candidates that have been extensively pursued for the treatment of cancer, but even over three decades after its discovery, we have not made much advancement in employing it as an anticancer therapeutic despite of its remarkable anti-angiogenic effect with low toxicity profile. A recombinant human endostatin (rh-Es) variant for non-small cell lung cancer was approved by China in 2006 and has since been used effectively. Several other successful clinical trials related to endostatin for various malignancies are either ongoing or have already been completed with promising results. Thus, in this review, we have provided an overview of existing anti-angiogenic drugs developed for cancer therapy, with a summary of tumour angiogenesis in the context of Endostatin, and clinical status of rh-Es in cancer treatment. Furthermore, we briefly discuss the various strategies to improve endostatin features (poor pharmacokinetic properties) for developing rh-Es as a safe and effective agent for cancer treatment.

North American Study for the Treatment of Recurrent Epistaxis with Doxycycline: The NOSTRIL trial

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a vascular bleeding disorder characterized by mucocutaneous telangiectasias and visceral arteriovenous malformations. A frequently debilitating symptom is spontaneous recurrent epistaxis.

OBJECTIVE

To evaluate whether doxycycline therapy improves epistaxis in HHT by using a prospective, randomized, placebo-controlled crossover study design.

PATIENTS/METHODS

Twenty-two eligible patients between December 2017 and July 2020 at a single center were randomized to one of two study arms: doxycycline treatment followed by placebo, or vice versa. Primary outcomes measured differences in epistaxis severity between treatments. Changes in quality of life, laboratory markers of bleeding, and number of monthly blood transfusions or iron infusions were assessed as secondary endpoints. Additional post hoc endpoints included frequency and duration of dripping epistaxis and gushing epistaxis. A post hoc longitudinal analysis assessed effects of doxycycline over time.

RESULTS/CONCLUSIONS

Doxycycline was safe and well tolerated. However, there was no reduction in the three primary outcome measures, nosebleed frequency (p = .16), nosebleed duration (p = .05), and Epistaxis Severity Score (p = .19). Quality of life, hemoglobin level, and number of blood transfusions and iron infusions did not differ between groups. Post hoc analysis demonstrated reduction in instances of gushing (p = .02) with doxycycline, although this finding is of unclear clinical significance. Post hoc longitudinal analysis showed reduction in frequency (mean estimate of coefficient = -0.19, standard error = 0.07, p = .01) and duration (mean estimate of coefficient = -2.33, standard error = 1.08, p = .03) of epistaxis over time. Post hoc findings suggest possible benefit of doxycycline but should be interpreted with caution given the overall negative study. Further investigation is needed with a larger sample size and a longer treatment duration.

Impact of long-term doxycycline on lung function & exacerbations: A real-world open, prospective pilot observation on chronic obstructive pulmonary disease

Background & objectives:

Upregulation of matrix metalloproteinases (MMPs) is related to the pathogenesis of chronic obstructive pulmonary disease (COPD). We aimed at assessing the tolerability and impact of long-term use of MMP inhibitor doxycycline in COPD.

Methods:

A cohort of COPD patients was randomized to continue a uniform COPD treatment with or without add-on long-term oral doxycycline. The lung exacerbations (spirometry), adverse events and health status (COPD Assessment Test score) were noted at 3, 6, 9 and 12 months of therapy. Measurement of the serum MMP-2, and 9 and high-sensitive C-reactive protein (hs-CRP) levels was done at the start of the study and at three months, whenever possible.

Results:

There were 27, 19, 13 and 10 patients with add-on doxycycline group and 22, 19, 11 and 7 patients with COPD treatment alone at 3, 6, 9 and 12 months of treatment respectively. The improvement was obviousaconsistent and serial improvement of health st nd mostly (at 6 and 12 months) significant (P>0.05) for lung function parameters [forced expiratory volume in one second (FEV₁), FEV₁/forced vital capacity (FVC) and forced expiratory flow at 25-75% of FVC (FEF_25-75)] and universal for health status at all measurements, with an overall 26.69 per cent reduction in exacerbations. The analysis with the lung function changes in the available population with protocol violation also supported the same trend. The concomitant reduction in serum MMP-9 (P=0.01), MMP-2 (P=0.01) and hs-CRP (P=0.0001) levels (n=21) at three months was also significant. The adverse reactions with add-on doxycycline appeared acceptable.

Interpretation & conclusions:

Long-term doxycycline appears well tolerated and seems to improve lung function, health status and exacerbations in COPD. The claim needs further scientific validations.

Hydrops Fetalis and Congenital Pulmonary Capillary Haemangiomatosis in a Premature Infant - A Case Report and Literature Review

Pulmonary capillary haemangiomatosis (PCH) is a rare disorder of the lung, well described in adult literature. PCH is characterized by capillary proliferation, infiltrating the interstitium and alveolar walls. This leads to development of respiratory distress and to end-stage pulmonary hypertension. Mostly young adults are affected. The affection of newborn is described in less than ten cases in literature in the past forty years. PCH is a mostly deadly ending disease. We present a preterm born infant with antepartal diagnosed hydrops fetalis, who died 30 minutes after birth. Autopsy revealed PCH as lethal reason and not cardial disease as presumed before.

Tetracyclines Modify Translation by Targeting Key Human rRNA Substructures

Apart from their antimicrobial properties, tetracyclines demonstrate clinically validated effects in the amelioration of pathological inflammation and human cancer. Delineation of the target(s) and mechanism(s) responsible for these effects, however, has remained elusive. Here, employing quantitative mass spectrometry-based proteomics, we identified human 80S ribosomes as targets of the tetracyclines Col-3 and doxycycline. We then developed in-cell click selective crosslinking with RNA sequence profiling (icCL-seq) to map binding sites for these tetracyclines on key human rRNA substructures at nucleotide resolution. Importantly, we found that structurally and phenotypically variant tetracycline analogs could chemically discriminate these rRNA binding sites. We also found that tetracyclines both subtly modify human ribosomal translation and selectively activate the cellular integrated stress response (ISR). Together, the data reveal that targeting of specific rRNA substructures, activation of the ISR, and inhibition of translation are correlated with the anti-proliferative properties of tetracyclines in human cancer cell lines.

Vasoproliferative process resembling pulmonary capillary hemangiomatosis in a cat

BACKGROUND

Pulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species.

CASE PRESENTATION

A 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis.

CONCLUSION

This is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.

Pulmonary veno-occlusive disease: Two children with gradual disease progression

Pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis are rare forms of pulmonary vascular disease. We report two cases of affected children who had evidence of pulmonary hypertension 3–5 years before developing radiographic findings of pulmonary veno-occlusive disease or pulmonary capillary hemangiomatosis. Both patients experienced a moderate decrease in pulmonary arterial pressure during acute vasodilator testing. Both patients experienced an improvement in six-minute walk performance without an increase in pulmonary edema when treated with targeted therapy for pulmonary hypertension. In some patients, pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis may progress slowly over a period of months to years. A favorable acute vasodilator response may identify patients who will tolerate, and demonstrate transient clinical improvement with, medical therapy.

Infantile pulmonary capillary haemangiomatosis: a lethal form of pulmonary hypertension

We describe the cases of two children who both presented in infancy with recurrent severe pulmonary hypertensive crises. Exhaustive clinical work-up failed to identify an underlying aetiology. The patients had no clinical response to steroids, immunoglobulins, or pulmonary vasodilators. Post-mortem examination revealed extensive invasive pulmonary capillary haemangiomatosis. There was no evidence of pulmonary venous occlusive disease. Given the lethal nature of this condition, early consideration of referral to a lung transplant centre should be considered in selected patients.

Pulmonary capillary hemangiomatosis: the role of invasive cardiopulmonary exercise testing

Pulmonary capillary hemangiomatosis (PCH) is a rare form of pulmonary arterial hypertension (PAH) characterized by pulmonary capillary proliferation and pseudoinvasion of collagenous septal structures. PCH is often accompanied by veno-occlusive changes and pulmonary hypertensive arterial remodeling. The clinical and pathological diagnosis of PCH can be subtle and easily missed. Most reported cases of PCH have been associated with resting PAH. We report the cases of 3 patients who initially presented with exertional dyspnea with normal to mildly elevated resting pulmonary arterial pressures and marked intrapulmonary shunting. In all 3 patients, invasive cardiopulmonary exercise testing was suggestive of pulmonary vascular disease. Owing to abnormalities on invasive exercise testing, lung biopsies were performed; these were diagnostic of PCH, and the patients were referred for lung transplantation. We describe unique features of these 3 cases-including novel pathological findings and the presence of intrapulmonary shunting in all 3 patients-and we discuss the role of cardiopulmonary exercise testing in the evaluation of PCH.

Pulmonary capillary hemangiomatosis: a focus on the EIF2AK4 mutation in onset and pathogenesis

Pulmonary capillary hemangiomatosis (PCH) is a pulmonary vascular disease that mainly affects small capillaries in the lung, and is often misdiagnosed as pulmonary arterial hypertension or pulmonary veno-occlusive disease due to similarities in their clinical presentations, prognosis, and management. In patients who are symptomatic, there is a high mortality rate with median survival of 3 years after diagnosis. Both idiopathic and familial PCH cases are being reported, indicating there is genetic component in disease etiology. Mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene were identified in familial and idiopathic PCH cases, suggesting EIF2AK4 is a genetic risk factor for PCH. EIF2AK4 mutations were identified in 100% (6/6) of autosomal recessively inherited familial PCH and 20% (2/10) of sporadic PCH cases. EIF2AK4 is a member of serine/threonine kinases. It downregulates protein synthesis in response to a variety of cellular stress such as hypoxia, viral infection, and amino acid deprivation. Bone morphogenetic protein receptor 2 (BMPR2) is a major genetic risk factor in pulmonary arterial hypertension and EIF2AK4 potentially connects with BMPR2 to cause PCH. L-Arginine is substrate of nitric oxide synthase, and L-arginine is depleted during the production of nitric oxide, which may activate EIF2AK4 to inhibit protein synthesis and negatively regulate vasculogenesis. Mammalian target of rapamycin and EIF2α kinase are two major pathways for translational regulation. Mutant EIF2AK4 could promote proliferation of small pulmonary arteries by crosstalk with mammalian targets of the rapamycin signaling pathway. EIF2AK4 may regulate angiogenesis by modulating the immune system in PCH pathogenesis. The mechanisms of abnormal capillary angiogenesis are suggested to be similar to that of tumor vascularization. Specific therapies were developed according to pathogenesis and are proved to be effective in reported cases. Targeting the EIF2AK4 pathway may provide a novel therapy for PCH.

Role of doxycycline to resolve different types of non-malignant lung and pleural pathology: The results of a pilot observation

BACKGROUND

Lung lesions may develop from tissue reactions to known or unknown stimuli and present with different morphological descriptions. The pathogenesis may be induced and maintained by different bioactive substances, of which, the upregulation matrix metalloproteinases (MMPs) play a vital role. Inhibition of the MMPs, therefore, may be a prospective mode of therapy for such lesions.

MATERIALS AND METHODS

A number of patients with lung lesions of different morphologies and presentations were treated empirically with long-term oral doxycycline (100 mg BID) upon exclusion of malignancy and infection in an open, single-arm, prospective, observational pilot study. The effect of the treatment was recorded on serial x-rays/computed tomography (CT) scans and the impact of treatment was measured with a visual analog scale (VAS) or a Likert-like scale. Furthermore, six independent pulmonologists' opinion (expressed on a '0' to '100' scale) were pooled with regard to the significance and the expectedness of such a change.

RESULTS

Twenty-six patients (mean age 49.33 years and male: female ratio = 10:3) with different types of pulmonary parenchymal/pleural lesions were treated with long-term oral doxycycline for a mean duration of 386.88 days related to the available radiological comparison. They showed a mean improvement of 3.99 on the Likert-like scale and 78% on the VAS scale. The mean significance of the change was 83.33%, with a mean expectedness of 18% as per the pooled opinion of the pulmonologists.

INFERENCE

The significant and unexpected resolution of different tissue lesions from long-term doxycycline appears to be a novel observation. This needs proper scientific validation.

EIF2AK4 mutations in pulmonary capillary hemangiomatosis

BACKGROUND

Pulmonary capillary hemangiomatosis (PCH) is a rare disease of capillary proliferation of unknown cause and with a high mortality. Families with multiple affected individuals with PCH suggest a heritable cause although the genetic etiology remains unknown.

METHODS

We used exome sequencing to identify a candidate gene for PCH in a family with two affected brothers. We then screened 11 unrelated patients with familial (n = 1) or sporadic (n = 10) PCH for mutations.

RESULTS

Using exome sequencing, we identified compound mutations in eukaryotic translation initiation factor 2 α kinase 4 (EIF2AK4) (formerly known as GCN2) in both affected brothers. Both parents and an unaffected sister were heterozygous carriers. In addition, we identified two EIF2AK4 mutations in each of two of 10 unrelated individuals with sporadic PCH. EIF2AK4 belongs to a family of kinases that regulate angiogenesis in response to cellular stress.

CONCLUSIONS

Mutations in EIF2AK4 are likely to cause autosomal-recessive PCH in familial and some nonfamilial cases.

Pulmonary capillary haemangiomatosis - An unusual cause of hypoxia

We describe the case of a 58-year-old man who presented with progressive dyspnoea on exertion and severe exertional hypoxia. There was a paucity of radiological findings, mild pulmonary hypertension, and no demonstrable anatomical shunt. Post mortem examination of lung tissue suggested a diagnosis of pulmonary capillary haemangiomatosis. The case is unusual in displaying few radiological findings. We postulate that the severe hypoxia was due to shunting through the abnormal capillary proliferations.

[Histopathological aspects of pulmonary hypertension]

In pulmonary hypertension there is a discrepancy between the dramatic but unspecific clinical presentation and the remodeling of mostly only limited segments of the vascular compartment of pulmonary parenchyma. Clinical diagnosis relies for the most part on invasive procedures, such as right heart catheterization. Therefore, morphology can provide a reliable etiopathogenetic classification only in close cooperation with the clinical partner disciplines involved. Moreover, the histopathological approach requires intimate knowledge of the vascular anatomy of the lungs and assessment of the parenchyma to be able to diagnose pulmonary hypertension and differentiate between the various types.

Familial pulmonary capillary hemangiomatosis early in life

Background. Pulmonary capillary hemangiomatosis (PCH) is a rare disease, especially in infancy. Four infants have been reported up to the age of 12 months. So far, no familial patients are observed at this age. Patients. We report three siblings, two female newborns and a foetus of 15-week gestation of unrelated, healthy parents suffering from histologically proven PCH. The first girl presented with increased O₂ requirements shortly after birth and patent ductus arteriosus (PDA). She subsequently developed progressive respiratory failure and pulmonary hypertension and died at the age of five months. The second girl presented with clinical signs of bronchial obstruction at the age of three months. The work-up showed a PDA—which was surgically closed—pulmonary hypertension, and bronchial wall instability with stenosis of the left main bronchus. Transient oxygen therapy was required with viral infections. The girl is now six years old and clinically stable without additional O₂ requirements. Failure to thrive during infancy and a somewhat delayed development may be the consequence of the disease itself but also could be attributed to repeated episodes of respiratory failure and a long-term systemic steroid therapy. The third pregnancy ended as spontaneous abortion. The foetus showed histological signs of PCH. Conclusion. Despite the differences in clinical course, the trias of PCH, PDA, and pulmonary hypertension in the two life born girls suggests a genetic background.

An alternative therapy for idiopathic pulmonary fibrosis by doxycycline through matrix metalloproteinase inhibition

BACKGROUND

Idiopatiic pulmonary fibrosis (IPF) is a disease of dysregulated fibrogenesis with abnormal matrix metalloproteinase (MMPs) activity, angiogenesis, and profibrotic milieu wherein MMPs inhibition appears to be target-based therapy. We evaluated the role of doxycycline as a nonspecific inhibitor of MMPs in IPF patients.

MATERIALS AND METHODS

Patients of IPF diagnosed on the basis of ATS-ERS consensus criteria were put on oral doxycycline in an open prospective trial. They were followed up for long term with spirometry, 6 min walk test (6MWT), St. Georges respiratory questionnaire (SGRQ), forced vital capacity (FVC), and repeat bronchoscopy while on doxycycline monotherapy for over 24 weeks. Both the initial and follow-up broncho alveolar lavage fluids (BALF) from IPF patients (n = 6) and control subjects (n = 6) were looked for MMP-9, -3, tissue inhibitor of metalloproteinase (TIMP)-1 and vascular endothelial growth factor (VEGF) expression. Additionally, doxycycline's action on MMP activities in vitro was tested in BALF of IPF patients.

RESULTS

Doxycycline intervention showed significant improvement in IPF patients in terms of change in 6MWT, SGRQ, FVC, and quality of life. The level of MMP-9, -3, TIMP-1 and VEGF in the BALF were found significantly higher in the IPF patients compared to the controls while doxycycline therapy reduced those parameters nearer to control value. Doxycycline also showed a significant dose-dependent reduction in the in vitro MMPs activities in BALF.

CONCLUSION

Doxycycline shows significant prospect in the treatment of IPF through its anti MMPs activities. This is the first report on a case series of long-term doxycycline monotherapy in IPF patients.

The role of long-term doxycycline in patients of idiopathic pulmonaryfibrosis: The results of an open prospective trial

Objective:

To evaluate the effect of long term use of doxycycline in IPF patients.

Materials and Methods:

Patients of IPF, selected randomly from out patient services and diagnosed on the basis of HRCT chest, were put on doxycycline in an open prospective trial. They were followed up with monitoring of subjective well being along with measurement of pulse rate and arterial oxygen saturation at rest and after a fixed and certain exercise, forced vital capacity, six minutes walk test, St Georges Respiratory questionnaire, and serial chest X-rays.

Results:

Out of seven patients put on doxycycline, six of them continued the drug for a mean period of 531.43 (± 328.88 days). All the patients tolerated the drug well and had shown uniform subjective and overall objective improvement in all the parameters concerned; the change in the radiological parameter being statistically significant.

Conclusion:

Doxycycline merits an appropriate clinical trial in the management of idiopathic pulmonary fibrosis. This widely used and relatively safe drug can add a new dimension to the therapeutic regimen. However, further in-depth studies will be required to evaluate its role in the management of IPF.

A 7-year-old with pulmonary hypertension

The authors discuss the case of a 7-year-old female who presented with exertional cyanosis and was found to have pulmonary arterial hypertension. Despite normal left-sided heart function, the patient developed pulmonary oedema in response to pulmonary vasodilator therapy, increasing suspicion for pathology in the pulmonary capillaries and veins. Lung biopsy confirmed a diagnosis of pulmonary capillary haemangiomatosis (PCH), a rare cause of pulmonary hypertension in both children and adults. The diagnosis requires lung biopsy and is often made postmortem. She was treated with interferon α-2a and doxycycline for their antiangiogenic properties and reports of disease regression. Although she initially demonstrated improvement in her pulmonary hypertension in response to these medications, she succumbed to the disease within the time frame previously reported for PCH.

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.

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.

Non-congenital heart disease associated pediatric pulmonary arterial hypertension

Recognition of causes of pulmonary hypertension other than congenital heart disease is increasing in children. Diagnosis and treatment of any underlying cause of pulmonary hypertension is crucial for optimal management of pulmonary hypertension. This article discusses the available knowledge regarding several disorders associated with pulmonary hypertension in children: idiopathic pulmonary arterial hypertension (IPAH), pulmonary capillary hemangiomatosis, pulmonary veno-occlusive disease, hemoglobinopathies, hepatopulmonary syndrome, portopulmonary hypertension and HIV. Three classes of drugs have been extensively studied for the treatment of IPAH in adults: prostanoids (epoprostenol, treprostinil, iloprost, beraprost), endothelin receptor antagonists (bosentan, sitaxsentan, ambrisentan), and phosphodiesterase inhibitors (Sildenafil, tadalafil). These medications have been used in treatment of children with pulmonary arterial hypertension, although randomized clinical trial data is lacking. As pulmonary vasodilator therapy in certain diseases may be associated with adverse outcomes, further study of these medications is needed before widespread use is encouraged.

Pulmonary capillary hemangiomatosis imaging findings and literature update

Pulmonary capillary hemangiomatosis (PCH) is a rare and an only recently described vascular disease. As one of the causes of primary pulmonary hypertension, the need for the establishment of helpful diagnostic radiological criteria for this condition has become imperative. However, the unstable hemodynamic condition of patients with primary pulmonary hypertension often denies pathological sampling as a definitive diagnostic tool. This diagnostic dilemma can be fatal to those patients with PCH treated for pulmonary hypertension because a fatal pulmonary edema may occur. We report a case of PCH in a 26-year-old patient who died of severe circulatory compromise while undergoing transplant evaluation. A discussion of the computed tomography findings, a review of the pathological features, and a review of the relatively limited imaging literature available on this subject are conducted.

From the Archives of the AFIP: pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis

Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are two unusual idiopathic disorders that almost uniformly manifest to the clinician as pulmonary arterial hypertension (PAH). Impressive clinical signs and symptoms often obscure the true underlying capillary or postcapillary disorder, thus severely compromising timely and appropriately directed therapy. The hemodynamics of PVOD and PCH are the consequence of a widespread vascular obstructive process that originates in either the alveolar capillary bed (in cases of PCH) or the pulmonary venules and small veins (in PVOD). Since the earliest descriptions of PVOD and PCH, there has been a debate as to whether these are two distinct diseases or varied expressions of a single disorder. The cause of PVOD or PCH has not yet been identified, although there are several reported associations. Without curative lung or heart-lung transplantation, patients with these conditions face inexorable clinical deterioration and death within months to a few short years of initial presentation. Surgical lung biopsy is the definitive diagnostic test, but it is a risky undertaking in such critically ill patients. The imaging manifestations of PVOD and PCH often reflect the underlying hemodynamic derangements, and these findings may assist the clinician in discerning PAH from an underlying capillary or postcapillary process with findings of septal lines, characteristic ground-glass opacities, and occasionally pleural effusion.

Platelet-Derived Growth Factor Is Increased in Pulmonary Capillary Hemangiomatosis

BACKGROUND

Pulmonary capillary hemangiomatosis (PCH) is a rare cause of pulmonary arterial hypertension with no effective medical therapy and a high risk of mortality. The pathogenesis of PCH is unknown.

METHODS

We used gene expression analysis to compare lung tissue samples from two patients with PCH to those from seven control subjects. The nodules of proliferating capillaries in PCH patients were needle microdissected from cryostat sections. RNA extraction and labeling were followed by hybridization to U95Av2 oligonucleotide arrays (Affymetrix; Santa Clara, CA). In situ hybridization and immunohistochemistry were also performed.

RESULTS

The gene expression profile of PCH allowed for unsupervised clustering from the profile of the lung tissue samples of control subjects. Platelet-derived growth factor (PDGF)-B gene (PDGFB), PDGF receptor (PDGFR)-beta gene (PDGFR-beta), mast cell-related genes, and type 2 pneumocyte-related genes were found to be overexpressed in PCH lesions. In situ hybridization as well as immunohistochemistry for PDGFB showed expression by type 2 pneumocytes and endothelial cells. Immunohistochemical staining for PDGFR-beta localized to pericytic/vascular smooth muscle cells surrounding the proliferating capillaries. CD117 staining confirmed an abundance of mast cells in the lesions, which also stained heavily for PDGFR-beta.

CONCLUSIONS

The expression of the PDGFB and PDGFR-beta genes characterizes the nodular proliferations of PCH. Increased numbers of mast cells, pericytes, and type II pneumocytes accompany the endothelial proliferation. The up-regulation of these important angiogenic and antiapoptotic genes suggests a mechanism and potential therapeutic approaches for PCH.

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.

Molecular pathogenesis of lymphangioleiomyomatosis: lessons learned from orphans

Lymphangioleiomyomatosis (LAM) is a rare progressive cystic lung disease affecting young women. The pivotal observation that LAM occurs both spontaneously and as part of the tuberous sclerosis complex (TSC) led to the hypothesis that these disorders share common genetic and pathogenetic mechanisms. In this review we describe the evolution of our understanding of the molecular and cellular basis of LAM and TSC, beginning with the discovery of the TSC1 and TSC2 genes and the demonstration of their involvement in sporadic (non-TSC) LAM. This was followed by rapid delineation of the signaling pathways in Drosophila melanogaster with confirmation in mice and humans. This knowledge served as the foundation for novel therapeutic approaches that are currently being used in human clinical trials.

Angiogenesis

Angiogenesis inhibitors for the treatment of cancer have now been approved by the Food and Drug Administration in the United States, and in 28 other countries including China. Clinical application of this new class of drugs is informed by certain principles from angiogenesis research. Oncogenic mutations initiate tumorigenesis, but angiogenesis is necessary for expansion of tumor mass. Two angiogenesis inhibitors have been developed that have a broad spectrum of anticancer activity, yet virtually no side effects. Endogenous angiogenesis inhibitors act as tumor suppressor proteins. The angiogenic response in vivo is based on the genetic background of the host. Several types of angiogenesis inhibitors reveal a biphasic, U-shaped curve of efficacy. "Antiangiogenic chemotherapy" is a novel approach to the treatment of drug resistance.

Hemangiomatose capilar pulmonar, uma rara causa de hipertensão pulmonar: primeiro caso brasileiro

A hemangiomatose capilar pulmonar é uma doença rara, caracterizada por proliferação de capilares que invadem o interstício pulmonar e o septo alveolar. Documentamos o primeiro caso brasileiro: um paciente do sexo masculino, de 21 anos, com hipertensão pulmonar grave, que evoluiu para óbito. Na tomografia computadorizada de alta resolução apresentava pequenas opacidades intersticiais nodulares maldefinidas, bilateralmente. Foi realizada biópsia pulmonar post-mortem e encontrada intensa proliferação multifocal de capilares nas paredes alveolares, septos interlobulares e tecido conjuntivo peribrônquico. O diagnóstico de hemangiomatose capilar pulmonar deve ser considerado nos pacientes com hipertensão pulmonar e alterações sugestivas na tomografia computadorizada de alta resolução.

Increased expression of urinary matrix metalloproteinases parallels the extent and activity of vascular anomalies

OBJECTIVE

Matrix metalloproteinases (MMPs) and the angiogenic proteins basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have been implicated in mechanisms of human cancer and metastasis. Assays were conducted on the urine of patients with vascular anomalies (tumors and malformations), relatively common and occasionally life-threatening disorders for which few therapies exist. We sought to determine whether these angiogenesis modulators are present in the urine and whether their expression is associated with the extent and clinical course of the vascular lesion.

METHODS

A total of 217 patients with vascular anomalies and 74 age-matched control subjects participated. Urinary MMP expression was determined by substrate gel electrophoresis. Urinary bFGF and VEGF levels were measured by enzyme-linked immunosorbent assay. Each patient was assigned to 1 of 2 categories (tumor or malformation) and 1 of 9 specific groups. Extent of the vascular lesion and activity were scored by a blinded clinician.

RESULTS

Urinary high molecular weight (hMW) MMPs and bFGF were significantly increased in patients with vascular tumors (53%) and vascular malformations (41%), compared with control subjects (22%). These percentages increased as a function of extent of the lesion and disease activity. hMW MMPs were increased in 4 groups: infantile hemangioma, other vascular neoplasms, lymphatic malformation and capillary-lymphaticovenous malformations, and extensive and unremitting capillary malformation and arteriovenous malformation. No significant differences among the groups were detected for low molecular weight MMPs or VEGF.

CONCLUSIONS

Expression patterns of hMW MMPs and bFGF in the urine of patients with tumors and malformations are consistent with their different clinical behavior. These data represent the first evidence that MMPs are elevated in the urine of children with vascular anomalies. These data also suggest that the increased expression of urinary MMPs parallels the extent and activity of vascular anomalies in children. In addition to tumors, vascular malformations are angiogenesis dependent, suggesting that progression of a vascular malformation might be suppressed by angiogenic inhibitors, which would target bFGF and MMPs.

Pulmonary capillary haemangiomatosis in a premature infant

Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant.

Inhibition by doxycycline of angiogenesis in the chicken chorioallantoic membrane (CAM)

Doxycycline, a tetracycline derivative, has many properties in addition to its antibiotic activity, including inhibition of matrix metalloproteinases (MMPs) and the ability to chelate divalent cations including Ca(2+). It has been shown to inhibit endothelial cell growth in vitro, and reduce the development of experimental tumours, especially bone metastasis in a model of breast cancer. We examined the effects of doxycycline on angiogenesis in the chicken chorioallantoic membrane (CAM) model, and showed that doxycycline will cause loss of the chorionic plexus in CAMs when applied at day 8 of incubation, and the duration of this inhibition was dose-dependent. Repeated doses prolonged the inhibition, but following removal of the doxycycline there was rapid recovery of the chorionic plexus. The effects of doxycycline are in part mimicked by the MMP inhibitor 1,10-phenanthroline, and more closely by the Ca(2+)-chelating agent EGTA. Doxycycline was equally effective in causing loss of the chorionic plexus by day 11 in CAMs, a time at which the blood vessels are established. Doxycycline has important potential as an antiangiogenic treatment. It is capable of inhibiting angiogenesis in an in vivo model, including the removal of comparatively mature endothelial cells. The response is sensitive to the dosing regimen and the effect is rapidly reversible.

Endogenous angiogenesis inhibitors

When the FDA commissioner announced in February 2004 the approval of Avastin for the treatment of patients with colon cancer, he called angiogenesis inhibitors a fourth modality of anti-cancer therapy. Because angiogenesis inhibitors are relatively less toxic than conventional chemotherapy and have a lower risk of drug resistance, they may also represent a new class of anti-cancer agents, some of which have sufficiently reduced toxicity that they may be safely used long term. These include immunotherapy, vaccines, telomerase inhibitors, apoptosis inducers, low dose metronomic chemotherapy, novel hormonal therapies, gene therapy and others. However, at least 16 endogenous angiogenesis inhibitors have been discovered in the circulation, and/or in the extracellular matrix. These may become the safest and least toxic of anti-cancer therapies. Four are already being administered by injection in clinical trials for cancer. Recently, it has been reported that at least two endogenous angiogenesis inhibitors can be significantly increased in humans (endostatin), and in mice (thrombospondin), by oral administration of small molecules which themselves are already FDA approved for other uses. This finding suggests several new clinical applications for the future, including the possibility of guiding the use of angiogenesis inhibitors by blood or urinary biomarkers, currently being developed, that may detect the presence of cancer before it is symptomatic, or before it can be located by conventional methods.

Pulmonary capillary haemangiomatosis in children and adolescents: report of a new case and a review of the literature

Pulmonary capillary haemangiomatosis (PCH) in childhood is a rarity, characterised by the uncontrolled proliferation of pulmonary microvessels which may invade pulmonary, bronchial and vascular structures, resulting in diffuse alveolar haemorrhage, manifesting clinically in haemoptysis, dyspnoea and symptoms of pulmonary hypertension (PH). A 14-year-old boy with some particular features (pericardial effusion and thrombocytopenia) is presented and 14 paediatric/adolescent cases from the literature are surveyed. The diagnostic problems and difficulties are discussed, including the importance of imaging (high-resolution CT) and histopathological studies, with the aim of providing a clear-cut distinction of PCH from other conditions such as primary PH (PPH). The literature data can be regarded as ambiguous: both similarities and relatively sharp distinctions between PCH and PPH are to be found. New developments in the field of genetics are also discussed. The early coexistence of PCH and other (vascular) disorders and associations, involving focal or diffuse, disseminated forms is summarised briefly. Conclusion. The diagnosis of this progressive disorder may lead to effective therapy. Treatment possibilities include the rapidly evolving field of anti-angiogenic therapy, but at present lung transplantation is universally accepted as the final definitive treatment for pulmonary capillary haemangiomatosis.