Heiko Golpon

Gene Expression Patterns in the Lungs of Patients With Primary Pulmonary Hypertension A Gene Microarray Analysis

Abstract— Primary pulmonary hypertension (PPH) is a disease of unknown etiology characterized by lumen-obliterating endothelial cell proliferation and vascular smooth muscle hypertrophy of the small precapillary pulmonary arteries. Because the vascular lesions are homogeneously distributed throughout the entire lung, we propose that a tissue fragment of the lung is representative of the whole lung. RNA extracted from the fragments is likely to provide meaningful information regarding the changes in gene expression pattern in PPH when compared with structurally normal lung tissue. We hypothesize that the lung tissue gene expression pattern of patients with PPH has a characteristic profile when compared with the gene expression pattern of structurally normal lungs and that this characteristic gene expression profile provides new insights into the pathobiology of PPH. Using oligonucleotide microarray technology, we characterized the expression pattern in the lung tissue obtained from 6 patients with primary pulmonary hypertension (PPH)—including 2 patients with the familial form of PPH (FPPH)—and from 6 patients with histologically normal lungs. For the data analysis, gene clusters were generated and the gene expression pattern differences between PPH and normal lung tissue and between PPH and FPPH lung tissue were compared. All PPH lung tissue samples showed a decreased expression of genes encoding several kinases and phosphatases, whereas several oncogenes and genes coding for ion channel proteins were upregulated in their expression. Importantly, we could distinguish by pattern comparison between sporadic PPH and FPPH, because alterations in the expression of transforming growth factor-&bgr; receptor III, bone morphogenic protein 2, mitogen-activated protein kinase kinase 5, RACK 1, apolipoprotein C-III, and the gene encoding the laminin receptor 1 were only found in the samples from patients with sporadic PPH, but not in FPPH samples. We conclude that the microarray gene expression technique is a new and useful molecular tool that provides novel information pertinent to a better characterization and understanding of the pathobiology of the distinct clinical phenotypes of pulmonary hypertension.

Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) Expression Is Decreased in Pulmonary Hypertension and Affects Endothelial Cell Growth

Abstract— PPAR&ggr; is a member of a family of nuclear receptors/ligand–dependent transcription factors, which bind to hormone response elements on target gene promoters. An antiproliferative and proapoptotic action profile of PPAR&ggr; has been described and PPAR&ggr; may function as a tumor suppressor gene, but little is known about the role of PPAR&ggr; in vascular remodeling. One group of human diseases that shows impressive vascular remodeling exclusively in the lungs is the group of severe pulmonary hypertensive disorders, which is characterized by complex, endothelial cell–proliferative lesions of lung precapillary arterioles composed of clusters of phenotypically altered endothelial cells that occlude the vessel lumen and contribute to the elevation of the pulmonary arterial pressure and reduce local lung tissue blood flow. In the present study, we report the ubiquitous PPAR&ggr; expression in normal lungs, and in contrast, a reduced lung tissue PPAR&ggr; gene and protein expression in the lungs from patients with severe PH and loss of PPAR&ggr; expression in their complex vascular lesions. We show that fluid shear stress reduces PPAR&ggr; expression in ECV304 endothelial cells, that ECV304 cells that stably express dominant-negative PPAR&ggr; (DN-PPAR&ggr; ECV304) form sprouts when placed in matrigel and that DN-PPAR&ggr; ECV304 cells, after tail vein injection in nude mice, form lumen-obliterating lung vascular lesions. We conclude that fluid shear stress decreases the expression of PPAR&ggr; in endothelial cells and that loss of PPAR&ggr; expression characterizes an abnormal, proliferating, apoptosis-resistant endothelial cell phenotype.

Life after corpse engulfment: phagocytosis of apoptotic cells leads to VEGF secretion and cell growth

Removal of apoptotic cells by neighboring viable cells or professional phagocytes is essential for the maintenance of tissue homeostastis. Here we show that the phagocytosis of apoptotic Jurkat T cells by mouse epithelial cells (HC‐11) and peritoneal macrophages leads to the secretion of growth and survival factors. We characterized VEGF as one of these factors which subsequently promote the proliferation of endothelial cells. Further we demonstrate that the phagocytosis of apoptotic bodies inhibits both spontanous and UV‐irradiation‐induced apoptosis in endothelial and epithelial cells. These effects were not observed when phagocytes had been exposed to viable or necrotic Jurkat T cells. We conclude that phagocytosis of apoptotic cells leads to secretion of growth and survival factors by phagocytes that represents a new form of life‐promoting cell‐cell interaction.

Long-term azithromycin for bronchiolitis obliterans syndrome after lung transplantation.

Background. Bronchiolitis obliterans syndrome (BOS) is a major cause of morbidity and mortality after lung transplantation (LTx). Macrolides are a promising treatment option for BOS. The objective of this study was to determine long-term results of azithromycin treatment in patients with BOS. Variables to predict treatment response were evaluated. Methods. An observational study in a single center was performed. Eighty-one adult LTx-recipients (single, double, combined, and re-do) with at least BOS stage 0p (mean forced expired volume in 1 second [FEV1] 55±19%) were included. For treatment, 250 mg of oral azithromycin was administered three times per week. Results. Twenty-four of 81 (30%) patients showed improvement in FEV1 after 6 months, 22/24 already after 3 months of treatment. By univariate analysis, responders at 6 months had higher pretreatment bronchoalveolar lavage (BAL) neutrophils (51±29 vs. 21±24%). A cutoff value of <20% in pretreatment BAL had a negative predictive value of 0.91 for treatment response. Thirty-three patients (40%) showed disease progression during follow-up (491±165 days). Cox regression analysis identified a rapid pretreatment decline in FEV1 and comedication of an mammalian target of rapamycin inhibitor as positive predictors and proton pump inhibitor comedication and a treatment response at 3 months as negative predictors for disease progression (FEV1 <90% baseline). Conclusions. Azithromycin can improve airflow limitation in a significant proportion of patients with even long-standing BOS. The majority of responders were identified after 3 months of treatment. Results indicate the predictive value of BAL neutrophilia for treatment response and pretreatment course of FEV1 as a variable for disease progression. Beneficial effects on gastroesophageal reflux disease may be a mechanism of action.

Circulating endothelial cells in pulmonary hypertension

The pulmonary endothelium plays a significant role in the pathobiology of Primary Pulmonary Hypertension. A number of diseases, related by a history of vascular injury, are associated with increased numbers of circulating endothelial cells (CECs). We hypothesized that patients with pulmonary hypertension would also have an increased number of circulating endothelial cells due to the high pressures and increased shear stress present within the pulmonary vasculature. We isolated the CECs from 14 patients with pulmonary hypertension, (5 primary and 11 secondary) and compared them to the cells from 12 normal controls. There was a significant increase in the number of CECs in peripheral blood in patients with both PPH and secondary pulmonary hypertension (SPH) when compared to normal volunteers (33.1 +/- 1.9 [PPH] and 27.2 +/- 6.9 [SPH] vs. 3.5 +/- 1.3 [controls], p < 0.001). The number of circulating endothelial cells in the patients peripheral blood correlated significantly with the systolic, diastolic and mean pulmonary artery pressures of the individual. Approximately 50% of the CECs from patients with pulmonary hypertension expressed CD36, a marker of microvascular origin and 25% expressed E-selectin, a marker of endothelial cell activation. Although the origin of the CECs in patients with PH requires further investigation, one possible source is the pulmonary vasculature, and in patients with plexogenic pulmonary hypertension, the plexiform lesions. CECs may provide a non-invasive mean of accessing cells important to the pathobiology of severe pulmonary hypertension.

Severe pulmonary hypertension after the discovery of the familial primary pulmonary hypertension gene

The recent discoveries of the familial primary pulmonary hypertension gene and somatic mutations in key cell growth and cell death regulatory genes in primary pulmonary hypertension have added a new dimension to severe pulmonary hypertension research. These findings have already impacted on how the disease is viewed, and ultimately, how severe pulmonary hypertension is diagnosed and treated. However, this new information raises several fundamental questions related to the role of bone morphogenetic protein receptor signalling in the control of lung vascular cell function. Furthermore, additional genes and gene products may also be involved in the pathogenesis of the disease. The way severe pulmonary hypertension is viewed and studied is on the verge of shifting from a vasoconstrictive to a cell growth paradigm.

Therapy preferences of patients with lung and colon cancer: a discrete choice experiment

Objectives There is increasing interest in studies that examine patient preferences to measure health-related outcomes. Understanding patients’ preferences can improve the treatment process and is particularly relevant for oncology. In this study, we aimed to identify the subgroup-specific treatment preferences of German patients with lung cancer (LC) or colorectal cancer (CRC). Methods Six discrete choice experiment (DCE) attributes were established on the basis of a systematic literature review and qualitative interviews. The DCE analyses comprised generalized linear mixed-effects model and latent class mixed logit model. Results The study cohort comprised 310 patients (194 with LC, 108 with CRC, 8 with both types of cancer) with a median age of 63 (SD =10.66) years. The generalized linear mixed-effects model showed a significant (P<0.05) degree of association for all of the tested attributes. “Strongly increased life expectancy” was the attribute given the greatest weight by all patient groups. Using latent class mixed logit model analysis, we identified three classes of patients. Patients who were better informed tended to prefer a more balanced relationship between length and health-related quality of life (HRQoL) than those who were less informed. Class 2 (LC patients with low HRQoL who had undergone surgery) gave a very strong weighting to increased length of life. We deduced from Class 3 patients that those with a relatively good life expectancy (CRC compared with LC) gave a greater weight to moderate effects on HRQoL than to a longer life. Conclusion Overall survival was the most important attribute of therapy for patients with LC or CRC. Differences in treatment preferences between subgroups should be considered in regard to treatment and development of guidelines. Patients’ preferences were not affected by sex or age, but were affected by the cancer type, HRQoL, surgery status, and the main source of information on the disease.