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Abstract
Recent investigations have suggested that it might be possible to reverse the pathology of pulmonary arterial hypertension (PAH), a disorder that can be rapidly progressive and fatal despite current treatments including i.v. prostacyclin. This review will address the cellular and molecular processes implicated in clinical, genetic, and experimental studies as underlying the pulmonary vascular abnormalities associated with PAH. Emerging treatments are aimed at inducing apoptosis of abnormal vascular cells that obstruct blood flow and at promoting regeneration of "lost" distal vasculature.
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Affiliation(s)
- Marlene Rabinovitch
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California 94305-5162, USA.
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103
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Rabinovitch M. Pathobiology of pulmonary hypertension. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 2:369-99. [PMID: 18039104 DOI: 10.1146/annurev.pathol.2.010506.092033] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A variety of conditions can lead to the development of pulmonary arterial hypertension (PAH). Current treatments can improve symptoms and reduce the severity of the hemodynamic abnormality, but most patients remain quite limited, and deterioration in their condition necessitates a lung transplant. This review discusses current experimental and clinical studies that investigate the pathobiology of PAH. An emerging theme is the consideration of ways in which one might reverse the advanced occlusive structural changes in the pulmonary circulation causing PAH. The current debate concerning the role of regeneration through stem cells is presented. This review also highlights investigations in a number of laboratories relating the pathobiology of PAH to mutations causing loss of function of bone morphogenetic protein receptor II in patients with familial PAH, as well as sporadic cases.
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Affiliation(s)
- Marlene Rabinovitch
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California 94305, USA.
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104
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Abstract
Pulmonary artery hypertension (PAH) is now considered to be a proliferative disorder characterised by unexplained proliferation of pulmonary artery smooth muscle cells (PA-SMCs) and pulmonary artery endothelial cells (PA-ECs). An abnormal phenotype of PA-SMCs and PA-ECs has been described in PAH and some analogies now appear between pulmonary vascular cells from patients with PAH and cancer cells. Such analogies are discussed here with respect to essential hallmarks of cancer cells and with the hope that new treatments targeted at one or more of these cancer cell abnormalities may be appropriate for PAH.
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Affiliation(s)
- S Adnot
- INSERM U841 and Département de Physiologie, Hôpital H Mondor, AP-HP, Créteil, France.
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105
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Rai PR, Cool CD, King JAC, Stevens T, Burns N, Winn RA, Kasper M, Voelkel NF. The cancer paradigm of severe pulmonary arterial hypertension. Am J Respir Crit Care Med 2008; 178:558-64. [PMID: 18556624 DOI: 10.1164/rccm.200709-1369pp] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The plexiform lesions of severe pulmonary arterial hypertension (PAH) are similar in histologic appearance, whether the disease is idiopathic or secondary. Both forms of the disease show actively proliferating endothelial cells without evidence of apoptosis. Here, we discuss the pathobiology of the atypical, angioproliferative endothelial cells in severe PAH. The concept of the endothelial cell as a "quasi-malignant" cell provides a new framework for antiproliferative, antiangiogenic therapy in severe PAH.
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Affiliation(s)
- Pradeep R Rai
- Department of Pathology, University of Colorado at Denver and Health Sciences Center, Denver, Colorado, USA
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106
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Lu Q. Transforming growth factor-beta1 protects against pulmonary artery endothelial cell apoptosis via ALK5. Am J Physiol Lung Cell Mol Physiol 2008; 295:L123-33. [PMID: 18456797 DOI: 10.1152/ajplung.00402.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transforming growth factor (TGF)-beta1 has been reported to cause endothelial cell apoptosis. However, conflicting data have also demonstrated that TGF-beta1 promotes endothelial cell survival. In this study, the effect of TGF-beta1 on apoptosis of cultured bovine pulmonary artery endothelial cells (PAEC) induced by multiple stimuli was investigated. TGF-beta1 protected against apoptosis of bovine PAEC induced by serum deprivation or the VEGF receptor inhibitor SU-5416, but not by UV light exposure or TNFalpha. Neither caspase-8 nor caspase-12 was activated by serum deprivation or the VEGF receptor blocker. However, blockade of VEGF receptors activated caspase-9, an effect that was abolished by TGF-beta1. Furthermore, serum deprivation and inhibition of VEGF receptors significantly decreased the protein level of Bcl-2, an effect that was also abrogated by TGF-beta1. In addition, the baseline level of Bcl-2 was enhanced by TGF-beta1 and reduced by inhibition of activin receptor-like kinase 5 (ALK5), a TGF-beta1 type I receptor. Furthermore, inhibition of ALK5 caused apoptosis of bovine PAEC. These results suggest that TGF-beta1 signaling is critical for maintenance of bovine PAEC survival. Finally, the protective effects of TGF-beta1 on bovine PAEC apoptosis and Bcl-2 reduction were abolished by ALK5 inhibition, but not by inhibition of non-SMAD signaling pathways. Also, TGF-beta1 activated SMAD2 and SMAD1/5, an effect that was abolished by ALK5 inhibition. The results of this study suggest that TGF-beta1 protects against bovine PAEC apoptosis, possibly through ALK5-mediated Bcl-2 induction and subsequent inhibition of the mitochondria-mediated intrinsic pathway of apoptosis. Understanding the mechanism by which TGF-beta1 promotes endothelial cell survival may provide a better treatment for apoptosis-dependent vascular diseases, such as emphysema.
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Affiliation(s)
- Qing Lu
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, Rhode Island 02908, USA.
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107
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Rubin LJ. Treatment of Pulmonary Arterial Hypertension Due to Scleroderma: Challenges for the Future. Rheum Dis Clin North Am 2008; 34:191-7; viii. [DOI: 10.1016/j.rdc.2007.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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108
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Park DW, Song JM, Han KH, Lee CW, Kang DH, Lee SD, Joo SJ, Song H, Lee JW, Song JK. Different Gene Expression Patterns in the Lungs of Patients with Secondary Pulmonary Hypertension. Korean Circ J 2008. [DOI: 10.4070/kcj.2008.38.1.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Duk-Woo Park
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jong-Min Song
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Ki-Hoon Han
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Cheol Whan Lee
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Duk-Hyun Kang
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sang-Do Lee
- Division of Pulmonology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Suk-Jung Joo
- Division of Cardiac Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyun Song
- Division of Cardiac Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jae Won Lee
- Division of Cardiac Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jae-Kwan Song
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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109
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Meyrick BO, Friedman DB, Billheimer DD, Cogan JD, Prince MA, Phillips JA, Loyd JE. Proteomics of transformed lymphocytes from a family with familial pulmonary arterial hypertension. Am J Respir Crit Care Med 2007; 177:99-107. [PMID: 17932379 DOI: 10.1164/rccm.200703-499oc] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Not all family members with BMPR2 mutations develop pulmonary arterial hypertension (PAH), implying that additional modifier genes or proteins are necessary for full expression of the disease. OBJECTIVES To determine whether protein expression is altered in patients with familial PAH (FPAH) compared with obligate carriers and nondiseased control subjects. METHODS Protein extracts from transformed blood lymphocytes from four patients with FPAH, three obligate carriers, and three married-in control subjects from one family with a known BMPR2 mutation (exon 3 T354G) were labeled with either Cy3 or Cy5. Cy3/5 pairs were separated by standard two-dimensional differential gel electrophoresis using a Cy2-labeled internal standard of all patient samples. Log volume ratios were analyzed using a linear mixed-effects model. Proteins were identified by matrix-assisted laser desorption ionization, time-of-flight mass spectrometry (MALDI-TOF MS) and tandem TOF/TOF MS/MS. MEASUREMENTS AND MAIN RESULTS Hierarchical clustering, heat-map, and principal components analysis revealed marked changes in protein expression in patients with FPAH when compared with obligate carriers. Significant changes were apparent in expression of 16 proteins (P < 0.05) when affected patients were compared with obligates: nine showed a significant increase and seven showed a significant reduction. CONCLUSIONS A series of novel proteins with altered expression were found that could distinguish affected patients from obligate carriers and married-in controls in a single family with a BMPR2 mutation. These differences provide new information highlighting proteins that may be involved in the mechanism(s) that differentiates those individuals with a BMPR2 mutation who develop FPAH from those who do not.
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Affiliation(s)
- Barbara O Meyrick
- Department of Pathology, Vanderbilt University Medical Center, MCN T-1218, Nashville, TN 37232-2650, USA.
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110
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Chan SY, Loscalzo J. Pathogenic mechanisms of pulmonary arterial hypertension. J Mol Cell Cardiol 2007; 44:14-30. [PMID: 17950310 DOI: 10.1016/j.yjmcc.2007.09.006] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 09/14/2007] [Indexed: 01/06/2023]
Abstract
Pulmonary arterial hypertension (PAH) is a complex disease that causes significant morbidity and mortality and is clinically characterized by an increase in pulmonary vascular resistance. The histopathology is marked by vascular proliferation/fibrosis, remodeling, and vessel obstruction. Development of PAH involves the complex interaction of multiple vascular effectors at all anatomic levels of the arterial wall. Subsequent vasoconstriction, thrombosis, and inflammation ensue, leading to vessel wall remodeling and cellular hyperproliferation as the hallmarks of severe disease. These processes are influenced by genetic predisposition as well as diverse endogenous and exogenous stimuli. Recent studies have provided a glimpse at certain molecular pathways that contribute to pathogenesis; these have led to the identification of attractive targets for therapeutic intervention. We will review our current understanding of the mechanistic underpinnings of the genetic and exogenous/acquired triggers of PAH. The resulting imbalance of vascular effectors provoking pathogenic vascular changes will also be discussed, with an emphasis on common and overarching regulatory pathways that may relate to the primary triggers of disease. The current conceptual framework should allow for future studies to refine our understanding of the molecular pathogenesis of PAH and improve the therapeutic regimen for this disease.
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Affiliation(s)
- Stephen Y Chan
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
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111
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Upadhyaya SK, Kumar A. Pulmonary hypertension in connective tissue disease. INDIAN JOURNAL OF RHEUMATOLOGY 2007. [DOI: 10.1016/s0973-3698(10)60095-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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112
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Stewart DR, Cogan JD, Kramer MR, Miller WT, Christiansen LE, Pauciulo MW, Messiaen LM, Tu GS, Thompson WH, Pyeritz RE, Ryu JH, Nichols WC, Kodama M, Meyrick BO, Ross DJ. Is Pulmonary Arterial Hypertension in Neurofibromatosis Type 1 Secondary to a Plexogenic Arteriopathy? Chest 2007; 132:798-808. [PMID: 17573495 DOI: 10.1378/chest.06-3017] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is a common disorder of dysregulated tissue growth secondary to mutations in the tumor suppressor gene NF1. Pulmonary arterial hypertension (PAH) in patients with NF1 is hypothesized to be secondary to an underlying vasculopathy. METHODS We describe the entity we term NF1-associated PAH (NF1-PAH) in four new patients and update the data on four previously published reports of patients with PAH and NF1. We performed genetic testing of the bone morphogenic protein receptor 2 (BMPR2) gene, which mutated in 70% of patients with familial PAH and approximately 25% of patients with idiopathic PAH. We report, for the first time, pathologic findings in the autopsy-obtained lung of one patient with NF1-PAH. RESULTS Patients with NF1-PAH have a generally poor long-term prognosis. In four patients, we observed the mosaic pattern of lung attenuation on a CT scan of the chest, a radiographic finding that can be consistent with an underlying vasculopathy. No mutations or rearrangements in the BMPR2 gene were found. We observed complex plexiform lesions in the one available autopsy specimen. Similar lesions are a hallmark of plexogenic pulmonary arteriopathy and are associated with several severe types of PAH. (Plexiform lesions should not be confused with plexiform neurofibromas, which are distinctive tumors seen in NF1.) CONCLUSIONS Our findings suggest that NF1 should be considered as being "associated with PAH as outlined in the Revised Clinical Classification of Pulmonary Hypertension. Understanding the mechanism of PAH in NF1 may inform the pathogenesis of PAH, NF1-PAH itself, and other NF1-associated vasculopathies. The pulmonary vasculature should now be included among the arterial beds affected by NF1 vasculopathy.
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Affiliation(s)
- Douglas R Stewart
- National Human Genome Research Institute, National Institutes of Health, 49 Convent Dr, Building 49, Room 4A62, Bethesda, MD 20892, USA.
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113
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Ramos M, Lamé MW, Segall HJ, Wilson DW. Monocrotaline pyrrole induces Smad nuclear accumulation and altered signaling expression in human pulmonary arterial endothelial cells. Vascul Pharmacol 2007; 46:439-48. [PMID: 17336165 PMCID: PMC2570208 DOI: 10.1016/j.vph.2007.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 01/03/2007] [Accepted: 01/22/2007] [Indexed: 12/31/2022]
Abstract
The mechanistic relationship between the widely used monocrotaline model of primary pulmonary hypertension and altered TGFbeta family signaling due to genetic defects in the Bone Morphogenetic Protein type II receptor in affected humans has not been investigated. In this study we use fluorescent microscopy to demonstrate nuclear translocation of Smad 4 in human pulmonary arterial endothelial cell (HPAEC) cultures treated with monocrotaline pyrrole (MCTP), Bone Morphogenetic Protein (BMP) and TGFbeta. While MCTP induced transient nuclear accumulation of phosphorylated Smad 1 (P-Smad 1) and phosphorylated Smad 2 (P-Smad 2), only expression of P-Smad 1 was significantly altered in western blots. P-Smad 1 expression significantly increased 30 min following treatment with MCTP correlating with P-Smad 1 and Smad 4 nuclear translocation. Although a modest, but significant decrease in P-Smad 1 expression occurred 1 h after treatment, expression was significantly increased at 72 h. Evaluation of components of the signal and response pathway at 72 h showed decreased expression of the BMP type II receptor (BMPrII), no change in TGFbeta Activin Receptor-like Kinase 1 (Alk 1), no change in Smad 4 but increase in the inhibitory Smad 6, decrease in the alternate BMP signaling pathway p38(MAPK) but no change in the psmad1 response element ID 1. Our results suggest transient activation of Smad signaling pathways in initial MCTP endothelial cell toxicity, and a persistent dysregulation of BMP signaling. Electron microscopy of cell membrane caveoli revealed a dramatic decrease in these structures after 72 h. Loss of these structural elements, noted for their sequestration and inhibition of receptor activity, may contribute to prolonged alterations in BMP signaling.
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Affiliation(s)
- M Ramos
- Department of Veterinary Medicine, Pathology, Immunology, Microbiology, University of California, Davis, Davis, California 95616, USA
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114
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Abstract
The secondary role of pathology in the present clinical management of pulmonary hypertension (PH) reflects to some extent the limitations of the current understanding of the disease. Ample room exists for the diagnostic translation of the pathobiologic studies, with the goal of improving the diagnostic and prognostic power of the pathologic assessment of pulmonary vascular remodeling. This article seeks to show the complementarities of the pathology and pathobiology of PH.
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Affiliation(s)
- Rubin M Tuder
- Division of Cardiopulmonary Pathology, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Research Building, Baltimore, MD 21217, USA.
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115
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Abstract
Pulmonary arterial hypertension (PAH), a rare disease involving the pulmonary vascular circuit, is defined as an elevation in pulmonary arterial pressures and is characterized by symptoms of dyspnea, chest pain, and syncope. If left untreated, the disease carries a high mortality rate, with the most common cause of death being decompensated right heart failure. Over the past 5 years, there have been significant advances in this field in regards to understanding the pathogenesis, diagnosis, and classification of PAH. The availability of newer drugs has resulted in a radical change in the management of this disease with significant improvement in both quality of life and mortality. Ongoing research promises to lead to a more comprehensive understanding of the genetics, etiology, and pathogenesis of pulmonary arterial hypertension, which may ultimately translate into more effective therapeutic options.
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Affiliation(s)
- Anne V LaRaia
- Pulmonary Critical Care Unit and the Critical Care Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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116
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Abstract
Chronic lung diseases like COPD, severe progressive pulmonary hypertension (PH), and interstitial lung diseases all have a lung vascular disease component. Cellular and molecular mechanisms of pulmonary vascular remodeling have been experimentally explored in many animal models, and it is now clear that microvessels are involved. In emphysema patients, there is a loss of lung microvessels, and in many forms of severe PH there is obliteration of precapillary arterioles by angioproliferation. Thus, COPD/emphysema and severe angioproliferative PH are on the opposite ends of a spectrum of vascular biology responses. Animal experiments have provided insight regarding some of the initiating events that shape the various forms of pulmonary vascular remodeling. In pulmonary fibrosis and in the postinjury phase of acute lung injury, the angiogenic/angiostatic balance is also affected. This review will therefore discuss angiogenesis in several chronic lung diseases and will speculate on how altered vascular homeostasis may contribute to lung disease development.
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Affiliation(s)
- Norbert F Voelkel
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO.
| | - Ivor S Douglas
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO
| | - Mark Nicolls
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO
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117
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House SJ, Ginnan RG, Armstrong SE, Singer HA. Calcium/calmodulin-dependent protein kinase II-delta isoform regulation of vascular smooth muscle cell proliferation. Am J Physiol Cell Physiol 2007; 292:C2276-87. [PMID: 17267544 DOI: 10.1152/ajpcell.00606.2006] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is accumulating evidence that Ca(2+)-dependent signaling pathways regulate proliferation and migration of vascular smooth muscle (VSM) cells, contributing to the intimal accumulation of VSM that is a hallmark of many vascular diseases. In this study we investigated the role of the multifunctional serine/threonine kinase, calmodulin (CaM)-dependent protein kinase II (CaMKII), as a mediator of Ca(2+) signals regulating VSM cell proliferation. Differentiated VSM cells acutely isolated from rat aortic media express primarily CaMKIIgamma gene products, whereas passaged primary cultures of de-differentiated VSM cells express primarily CaMKIIdelta(2), a splice variant of the delta gene. Experiments examining the time course of CaMKII isoform modulation revealed the process was rapid in onset following initial dispersion and primary culture of aortic VSM with a significant increase in CaMKIIdelta(2) protein and a significant decrease in CaMKIIgamma protein within 30 h, coinciding with the onset of DNA synthesis and cell proliferation. Attenuating the initial upregulation of CaMKIIdelta(2) in primary cultured cells using small-interfering RNA (siRNA) resulted in decreased serum-stimulated DNA synthesis and cell proliferation in primary culture. In passaged VSM cells, suppression of CaMKIIdelta(2) activity by overexpression of a kinase-negative mutant, or suppression of endogenous CaMKII content using multiple siRNAs, significantly attenuated serum-stimulated DNA synthesis and cell proliferation. Cell cycle analysis following either inhibitory approach indicated decreased proportion of cells in G1, an increase in proportion of cells in G2/M, and an increase in polyploidy, corresponding with accumulation of multinucleated cells. These results indicate that CaMKIIdelta(2) is specifically induced during modulation of VSM cells to the synthetic phenotypic and is a positive regulator of serum-stimulated proliferation.
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Affiliation(s)
- Suzanne J House
- Center for Cardiovascular Sciences, Albany Medical College, 47 New Scotland Ave., Albany, NY 12208-3479, USA
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118
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Ra SW, Lee SD. Cellular and Molecular Pathophysiology of Idiopathic Pulmonary Arterial Hypertension. Tuberc Respir Dis (Seoul) 2007. [DOI: 10.4046/trd.2007.63.6.475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Seung Won Ra
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sang-Do Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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119
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Fischer C, Schneider M, Carmeliet P. Principles and therapeutic implications of angiogenesis, vasculogenesis and arteriogenesis. Handb Exp Pharmacol 2006:157-212. [PMID: 16999228 DOI: 10.1007/3-540-36028-x_6] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The vasculature is the first organ to arise during development. Blood vessels run through virtually every organ in the body (except the avascular cornea and the cartilage), assuring metabolic homeostasis by supplying oxygen and nutrients and removing waste products. Not surprisingly therefore, vessels are critical for organ growth in the embryo and for repair of wounded tissue in the adult. Notably, however, an imbalance in angiogenesis (the growth of blood vessels) contributes to the pathogenesis of numerous malignant, inflammatory, ischaemic, infectious and immune disorders. During the last two decades, an explosive interest in angiogenesis research has generated the necessary insights to develop the first clinically approved anti-angiogenic agents for cancer and blindness. This novel treatment is likely to change the face of medicine in the next decade, as over 500 million people worldwide are estimated to benefit from pro- or anti-angiogenesis treatment. In this following chapter, we discuss general key angiogenic mechanisms in health and disease, and highlight recent developments and perspectives of anti-angiogenic therapeutic strategies.
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Affiliation(s)
- C Fischer
- Centre for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, KULeuven, Campus Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium
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120
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Machado RD, Aldred MA, James V, Harrison RE, Patel B, Schwalbe EC, Gruenig E, Janssen B, Koehler R, Seeger W, Eickelberg O, Olschewski H, Elliott CG, Glissmeyer E, Carlquist J, Kim M, Torbicki A, Fijalkowska A, Szewczyk G, Parma J, Abramowicz MJ, Galie N, Morisaki H, Kyotani S, Nakanishi N, Morisaki T, Humbert M, Simonneau G, Sitbon O, Soubrier F, Coulet F, Morrell NW, Trembath RC. Mutations of the TGF-beta type II receptor BMPR2 in pulmonary arterial hypertension. Hum Mutat 2006; 27:121-32. [PMID: 16429395 DOI: 10.1002/humu.20285] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulmonary arterial hypertension (PAH) is clinically characterized by a sustained elevation in mean pulmonary artery pressure leading to significant morbidity and mortality. The disorder is typically sporadic, and in such cases the term idiopathic PAH (IPAH) is used. However, cases that occur within families (familial PAH (FPAH)) display similar clinical and histopathological features, suggesting a common etiology. Heterozygous mutations of a type II member of the TGF-beta cell signaling superfamily known as BMPR2 on chromosome 2q33 have been identified in many kindreds with FPAH, yet display both reduced penetrance and sex bias. This report presents the compilation of data for 144 distinct mutations that alter the coding sequence of the BMPR2 gene identified in 210 independent PAH subjects. This large data set characterizes the extent of sequence variation and reveals that the majority (71%) of mutations in FPAH and IPAH comprise nonsense, frameshift, and splice-site defects, and gene rearrangements. These predict premature termination of the transcript with likely loss through the process of nonsense-mediated decay (NMD). A total of 44 missense mutations were identified that substitute amino acid residues at highly conserved sites within recognized functional domains of the mature receptor. We assess this category of mutations in the context of their heterogeneous effects on cell signaling when assayed by in vitro cell-based systems. Disease-causing mutation hot-spots within BMPR2 are summarized. Taken together, these observations are likely to aid in the development of targeted mutation detection strategies relevant for patient management. Finally, we examine the age- and sex-dependent reduced penetrance of BMPR2 mutations by reviewing bmpr2 animal models and the requirement for additional genetic and/or environmental modifiers of disease. In conclusion, these data provide compelling genetic evidence that haploinsufficiency is the predominant molecular mechanism underlying disease predisposition, and support the concept of a critical threshold of signaling activity below which disease may be precipitated.
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Affiliation(s)
- Rajiv D Machado
- Division of Medical Genetics, Department of Genetics, University of Leicester, Leicester, United Kingdom
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121
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Abstract
Pulmonary arterial hypertension is a disease of the small pulmonary arteries characterized by vascular narrowing and increased pulmonary vascular resistance, which eventually leads to right ventricular failure. Vasoconstriction, vascular proliferation, remodeling of the pulmonary vessels, and thrombosis are all contributing factors to the increased vascular resistance seen in this disease. Pulmonary arterial hypertension develops as a sporadic disease (idiopathic), as an inherited disorder (familial), or in association with certain conditions (collagen vascular diseases, portal hypertension, human immunodeficiency virus infection, congenital systemic-to-pulmonary shunts, ingestion of drugs or dietary products, or persistent fetal circulation). The pathogenesis of pulmonary arterial hypertension is a complicated, multifactorial process. It seems doubtful that any one factor alone is sufficient to activate the necessary pathways leading to the development of this disease. Rather, clinically apparent pulmonary arterial hypertension most likely develops after a second insult occurs in an individual who is already susceptible owing to genetic factors, environmental exposures, or acquired disorders. Currently, there is no cure for pulmonary arterial hypertension but several novel therapeutic options are now available that can improve symptoms and increase survival.
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Affiliation(s)
- Azad Raiesdana
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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122
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Montani D, Yaïci A, Jaïs X, Sztrymf B, Cabrol S, Hamid A, Parent F, Sitbon O, Dartevelle P, Simonneau G, Humbert M. Hypertension artérielle pulmonaire. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1155-195x(06)43390-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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123
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Pulmonary Arterial Hypertension. Vasc Med 2006. [DOI: 10.1016/b978-0-7216-0284-4.50063-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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124
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Gillespie MN, Ziel KA, Grishko V, Campbell CC, Wilson GL. Genomic threats from physiological signals in lung vascular cells. Chest 2005; 128:611S-612S. [PMID: 16373863 DOI: 10.1378/chest.128.6_suppl.611s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Mark N Gillespie
- Department of Pharmacology, College of Medicine and Center for Lung Biology, University of South Alabama, Mobile, AL 36688, USA
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125
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Abstract
The pathobiology of pulmonary arterial hypertension (PAH) includes endothelial cell dysfunction and proliferation and migration of VSMCs. As PDGF has been implicated in these processes, Schermuly et al. hypothesized that altered PDGF signaling may be involved in the vascular remodeling observed in PAH. To explore this notion further, the authors evaluated the effects of the PDGF receptor inhibitor STI571 in 2 different animal models of pulmonary hypertension. In both models, after development of pulmonary vascular disease, administration of STI571 reversed pulmonary vascular changes. These studies provide preclinical proof of concept for the clinical development of a PDGF inhibitor as a targeted therapy for PAH patients.
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Affiliation(s)
- Robyn J Barst
- New York Presbyterian Pulmonary Hypertension Center, Columbia University College of Physicians & Surgeons, New York, New York 10032, USA.
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126
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Caldwell RL, Gadipatti R, Lane KB, Shepherd VL. HIV-1 TAT represses transcription of the bone morphogenic protein receptor-2 in U937 monocytic cells. J Leukoc Biol 2005; 79:192-201. [PMID: 16282533 DOI: 10.1189/jlb.0405194] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The bone morphogenetic protein receptor-2 (BMPR2) is a member of the transforming growth factor-beta receptor family and is expressed on the surface of several cell types including endothelial cells and macrophages. Recently, a cause for familial primary pulmonary hypertension (FPPH) has been identified as mutations in the gene encoding BMPR2. Three forms of pulmonary hypertension (PH) exist, including PPH, FPPH, and PH secondary to other etiologies (sporadic PH) such as drug abuse and human immunodeficiency virus (HIV) infection. It is interesting that these subtypes are histologically indistinguishable. The macrophage is a key target cell for HIV-1, significantly altering macrophage cell function upon infection. HIV-1 trans-activator of transcription (Tat), an immediate-early product of the HIV-1 lifecycle, plays an important role in mediating HIV-induced modulation of host cell function. Our laboratory has previously shown that Tat represses mannose receptor transcription in macrophages. In the current study, we examined activity from the BMPR2 promoter in the macrophage cell line U937 and potential regulation by Tat. Transfection of U937 cells with BMPR2 promoter-reporter constructs revealed dose-dependent repression of BMPR2 promoter activity in the presence of Tat. Experiments using truncations of the BMPR2 promoter localized Tat-mediated repression to the first 208 bases of the promoter. Decreased BMPR2 transcription resulted in altered downstream signaling. Similar to mothers against decapentaplegics (SMAD) phosphorylation and SMAD6 expression, in response to BMP2 treatment, were down-regulated after Tat treatment. Finally, HIV-1 infection and treatment with Tat protein of the U937 human monocytic cell line resulted in a decreased, endogenous BMPR2 transcript copy number.
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MESH Headings
- Bone Morphogenetic Protein Receptors, Type II/biosynthesis
- Bone Morphogenetic Protein Receptors, Type II/genetics
- Down-Regulation
- Endothelial Cells/metabolism
- Gene Products, tat/metabolism
- Gene Products, tat/pharmacology
- HIV Infections/genetics
- HIV Infections/metabolism
- HIV-1
- Humans
- Hypertension, Pulmonary/genetics
- Lectins, C-Type/biosynthesis
- Lectins, C-Type/genetics
- Macrophages/metabolism
- Macrophages/virology
- Mannose Receptor
- Mannose-Binding Lectins/biosynthesis
- Mannose-Binding Lectins/genetics
- Mutation
- Phosphorylation
- Protein Processing, Post-Translational
- Receptors, Cell Surface/biosynthesis
- Receptors, Cell Surface/genetics
- Response Elements/genetics
- Signal Transduction
- Smad6 Protein/biosynthesis
- Smad6 Protein/genetics
- U937 Cells
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Robert L Caldwell
- Department of Pathology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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127
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Zaiman A, Fijalkowska I, Hassoun PM, Tuder RM. One hundred years of research in the pathogenesis of pulmonary hypertension. Am J Respir Cell Mol Biol 2005; 33:425-31. [PMID: 16234331 PMCID: PMC2715349 DOI: 10.1165/rcmb.f307] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/15/2005] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ari Zaiman
- Department of Pathology, Division of Cardiopulmonary Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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128
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Majka SM, Beutz MA, Hagen M, Izzo AA, Voelkel N, Helm KM. Identification of novel resident pulmonary stem cells: form and function of the lung side population. Stem Cells 2005; 23:1073-81. [PMID: 15987674 DOI: 10.1634/stemcells.2005-0039] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Resident lung stem cells function to replace all lineages of pulmonary tissue, including mesenchyme, epithelium, and vasculature. The phenotype of the lung side population (SP) cells is currently under investigation; their function is currently unknown. Recent data suggest lung SP cells are an enriched tissue-specific source of organ-specific pulmonary precursors and, therefore, a source of adult stem cells. The adult lung SP cell population has been isolated and characterized for expression of markers indicative of stem cell, epithelial, and mesenchymal lineages. These studies determined that the adult mouse lung SP has epithelial and mesenchymal potential that resides within a CD45- mesenchymal subpopulation, as well as limited hematopoietic ability, which resides in the bone marrow-derived CD45+ subpopulation. The ability to identify these adult lung precursor cells allows us to further study the potential of these cells and their role in the regulation of tissue homeostasis and response to injury. The identification of this target population will potentially allow earlier treatment and, long term, a functional restoration of injured pulmonary tissue and lung health.
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Affiliation(s)
- Susan M Majka
- Department of Medicine, Cardiovascular Pulmonary Research Section, University of Colorado Health Sciences Center, 4200 East 9th Avenue, SOM 3811, mail stop B-133, Denver, Colorado 80262, USA.
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129
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Abstract
The combined effects of vasoconstriction, remodelling of the pulmonary vessel walls and in situ thrombosis contribute to the increase in pulmonary vascular resistance during pulmonary arterial hypertension. Vascular remodelling involves all the sheaths of the vessel wall and all the cell types of which it is composed (endothelial cells, smooth muscle cells, fibroblasts, inflammatory cells and platelets). Excessive vasoconstriction has been related to a defect in the function of expression of the potassium channels and endothelial dysfunction. This leads to chronic insufficiency in the production of vasodilators, notably nitrogen monoxide and prostacyclin and the excessive production of vasoconstrictors such as endotheline-1. These defects contribute to the increase in vascular tonus and pulmonary vascular remodelling and represent pertinent pharmacological targets. Certain growth factors, including those of the super-family of transforming growth factor beta, angiopoietine-1 and serotonin, may play a part in the pathogenesis of pulmonary arterial hypertension.
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Affiliation(s)
- Frédéric Perros
- Service de pneumologie et réanimation respiratoire, Centre des maladies vasculaires pulmonaires, UPRES EA 2705, Institut Paris Sud sur les cytokines, Hôpital Antoine Béclère, Université Paris-Sud, 157 rue de la porte de Trivaux, 92140 Clamart, France
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130
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Lu J, Shimpo H, Shimamoto A, Chong AJ, Hampton CR, Spring DJ, Yada M, Takao M, Onoda K, Yada I, Pohlman TH, Verrier ED. Specific inhibition of p38 mitogen-activated protein kinase with FR167653 attenuates vascular proliferation in monocrotaline-induced pulmonary hypertension in rats. J Thorac Cardiovasc Surg 2005; 128:850-9. [PMID: 15573069 DOI: 10.1016/j.jtcvs.2004.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES p38 mitogen-activated protein kinase is associated with many clinical entities characterized by inflammation. We postulated that inhibition of p38 mitogen-activated protein kinase with FR167653 attenuates inflammation and the development of pulmonary hypertension in monocrotaline-treated rats. METHODS Rats were divided into 4 groups: (1) the control group (daily 0.9% saline), (2) the FR group (daily FR167653, 2 mg . kg(-1) . d(-1)), (3) the MCT group (daily 0.9% saline the day after a single monocrotaline dose, 60 mg/kg), and (4) the MCT+FR group (daily FR167653, 2 mg . kg(-1) . d(-1), the day after a single MCT dose). Body weight, pulmonary artery pressure, and morphometric changes of the pulmonary artery with the histopathologic method were observed weekly for 4 weeks. Also, p38 mitogen-activated protein kinase activity and inflammatory cytokine expression in the lung were measured. RESULTS Four weeks after monocrotaline administration, mean pulmonary artery pressure in the MCT+FR group was lower than in the MCT group (MCT+FR vs MCT: 24.7 +/- 1.9 vs 36.5 +/- 2.1 mm Hg; P < .05). In morphometric analysis the percentage of medial wall thickness and the percentage of muscularization in the MCT+FR group were reduced compared with those in the MCT group after 4 weeks (P < .05); however, the number of macrophages was not significantly different. p38 mitogen-activated protein kinase activity was significantly attenuated in the MCT+FR group compared with in the MCT group (7.2 +/- 0.52 vs 2.1 +/- 0.23 fold-increase, P < .05, at 1 week). Although mRNA levels of tumor necrosis factor alpha and interleukin 1beta were reduced in the MCT+FR group compared with in the MCT group (tumor necrosis factor alpha: 1.18 +/- 0.36 vs 3.05 +/- 1.12 fold-increase, P < .05, at 2 weeks; interleukin 1beta: 2.2 +/- 0.34 vs 4.4 +/- 1.09 fold-increase, P < .05, at 1 week), FR167653 did not suppress increased monocyte chemotactic protein 1 mRNA expression induced by monocrotaline (3.2 +/- 0.62 vs 3.1 +/- 0.42 fold-increase, at 1 week). CONCLUSION FR167653 significantly attenuates the expression of inflammatory cytokines, ultimately preventing the progression of pulmonary hypertension. These results suggest that p38 mitogen-activated protein kinase might play a central role in the molecular events that underlie the development and progression of pulmonary hypertension.
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Affiliation(s)
- Jun Lu
- Departmrent of Thoracic and Cardiovascular Surgery, Mie University School of Medicine, Tsu, Japan
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131
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Carreira PE. Pulmonary hypertension in autoimmune rheumatic diseases. Autoimmun Rev 2004; 3:313-20. [PMID: 15246028 DOI: 10.1016/j.autrev.2003.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Accepted: 11/08/2003] [Indexed: 12/16/2022]
Abstract
Arterial pulmonary hypertension (PH) might be a complication of some autoimmune rheumatic diseases, specially systemic sclerosis. This form of arterial PH is indistinguishable from primary PH, characterised by the presence of plexiform lesions. Although for many years plexiform lesions have been considered end-stage scarring lesions, they are composed by actively proliferating endothelial cells that share many features with cancer cells. Endothelial cells within plexiform lesions in all forms of arterial PH show a decrease in the expression of vasodilator and anti-proliferative factors, and an increase in the expression of vasoconstrictor and angiogenic and mitogenic factors. These cells also show important alterations in growth and apoptosis key regulatory genes. Plexiform lesions are surrounded by inflammatory cell infiltrates, probably providing cytokines that may contribute to the endothelial cell proliferative process. All these data suggest that arterial PH might be seen as a proliferative endothelial cell process, which would open new therapeutic approaches for this devastating disease.
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MESH Headings
- Angiopoietin-1/metabolism
- Animals
- Apoptosis/genetics
- Autoimmune Diseases
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Humans
- Hypertension, Pulmonary/complications
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Hypertension, Pulmonary/physiopathology
- Inflammation/physiopathology
- Rheumatic Diseases
- Scleroderma, Systemic/immunology
- Scleroderma, Systemic/pathology
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Patricia E Carreira
- Servicio de reumatología, Hospital 12 de Octubre, Avda. de Córdoba S/N, 28041 Madrid, Spain.
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132
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Richter A, Yeager ME, Zaiman A, Cool CD, Voelkel NF, Tuder RM. Impaired transforming growth factor-beta signaling in idiopathic pulmonary arterial hypertension. Am J Respir Crit Care Med 2004; 170:1340-8. [PMID: 15361368 DOI: 10.1164/rccm.200311-1602oc] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mutations in transforming growth factor-beta family receptor-II, bone morphogenetic protein receptor-2, and activin-like kinase-1 have been associated with pulmonary hypertension. In the present study, we determined that pulmonary arteries in normal lungs and in lungs of patients with emphysema and idiopathic pulmonary arterial hypertension comparably expressed transforming growth factor-beta receptors I and II, Smad(1, 5, 8), Smad2, Smad3, Smad4, phosphorylated Smad(1, 5, 8), and phosphorylated Smad2 (the latter two both indicative of active in vivo signaling) in endothelial cells, as assessed by immunohistochemistry and quantitative morphometry. Medial or intimal smooth muscle cells had weak or absent expression of these molecules. In clear contrast to endothelial cell expression in pulmonary arteries and in endothelial cells lining incipient vessels within plexiform lesions of hypertensive lungs, endothelial cells present in the core of the lesions lacked expression of all examined members of the signaling molecules. These findings were made irrespective of the mutation status of bone morphogenetic protein receptor-2 in hypertensive patients. Our findings suggest that pulmonary artery endothelial cells in both normal and severely hypertensive lungs have active transforming growth factor-beta family signaling, and that loss of signaling might contribute to the abnormal growth of endothelial cells in plexiform lesions in idiopathic pulmonary arterial hypertension.
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Affiliation(s)
- Amy Richter
- Division of Cardiopulmonary Pathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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133
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Humbert M, Yaïci A, Sztrymf B, Montani D. [Pulmonary hypertension: from genetics to treatments]. REVUE DE PNEUMOLOGIE CLINIQUE 2004; 60:196-201. [PMID: 15545947 DOI: 10.1016/s0761-8417(04)72099-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Pulmonary hypertertension (PHT) is a rare disease defined by increased resistance of the pulmonary arteries inevitably leading to right heart failure if specific treatment is not given. This disease can occur sporadically (idiopathic or primary PHT), within a familial context (familial PHT, BMPR2 gene mutation), or occur as a complication of other diseases (connective tissue disease, congenital cardiomyopathy, human immunodeficiency virus infection, portal hypertension, use of anorexigenic agents). The incidence of primary PHT is 2 million cases per year, probably an underestimation due to the low specificity of clinical signs, predominantly exercise-induced dyspnea. Recent therapeutic advances (prostacyclin and endothelin receptor antagonists administered in continuous infusion) have improved the prognosis of this orphan disease. Inhaled iloprost and type 5 phosphodiesterase inhibitors should be evaluated for this indication. Lung transplantation is reserved for patients unresponsive to medical treatment.
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Affiliation(s)
- M Humbert
- Service de Pneumologie et Réanimation Respiratoire, Centre des Maladies Vasculaires Pulmonaires, UPRES EA 2705, Réseau INSERM-AFM sur l'hypertension artérielle pulmonaire, Hôpital Antoine-Béclère, Clamart.
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134
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Owens GK, Kumar MS, Wamhoff BR. Molecular regulation of vascular smooth muscle cell differentiation in development and disease. Physiol Rev 2004; 84:767-801. [PMID: 15269336 DOI: 10.1152/physrev.00041.2003] [Citation(s) in RCA: 2531] [Impact Index Per Article: 126.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The focus of this review is to provide an overview of the current state of knowledge of molecular mechanisms/processes that control differentiation of vascular smooth muscle cells (SMC) during normal development and maturation of the vasculature, as well as how these mechanisms/processes are altered in vascular injury or disease. A major challenge in understanding differentiation of the vascular SMC is that this cell can exhibit a wide range of different phenotypes at different stages of development, and even in adult organisms the cell is not terminally differentiated. Indeed, the SMC is capable of major changes in its phenotype in response to changes in local environmental cues including growth factors/inhibitors, mechanical influences, cell-cell and cell-matrix interactions, and various inflammatory mediators. There has been much progress in recent years to identify mechanisms that control expression of the repertoire of genes that are specific or selective for the vascular SMC and required for its differentiated function. One of the most exciting recent discoveries was the identification of the serum response factor (SRF) coactivator gene myocardin that appears to be required for expression of many SMC differentiation marker genes, and for initial differentiation of SMC during development. However, it is critical to recognize that overall control of SMC differentiation/maturation, and regulation of its responses to changing environmental cues, is extremely complex and involves the cooperative interaction of many factors and signaling pathways that are just beginning to be understood. There is also relatively recent evidence that circulating stem cell populations can give rise to smooth muscle-like cells in association with vascular injury and atherosclerotic lesion development, although the exact role and properties of these cells remain to be clearly elucidated. The goal of this review is to summarize the current state of our knowledge in this area and to attempt to identify some of the key unresolved challenges and questions that require further study.
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MESH Headings
- Aging/metabolism
- Animals
- Arteriosclerosis/genetics
- Cell Differentiation
- Cellular Senescence
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Humans
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/embryology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Phenotype
- Vascular Diseases/genetics
- Vascular Diseases/metabolism
- Vascular Diseases/pathology
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Affiliation(s)
- Gary K Owens
- Dept. of Molecular Physiology and Biological Physics, Univ. of Virginia School of Medicine, 415 Lane Rd., Medical Research Building 5, Rm. 1220, PO Box 801394, Charlottesville, VA 22908, USA.
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135
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Abstract
This article briefly discusses the traditional concepts of severe pulmonary hypertension and then details how the concept of severe pulmonary hypertension has moved from a vasoconstrictive to an angioproliferative disorder.
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Affiliation(s)
- Norbert F Voelkel
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Pathology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA.
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136
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Glaus TM, Soldati G, Maurer R, Ehrensperger F. Clinical and pathological characterisation of primary pulmonary hypertension in a dog. Vet Rec 2004; 154:786-9. [PMID: 15233456 DOI: 10.1136/vr.154.25.786] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Primary pulmonary hypertension was diagnosed in an eight-year-old labrador retriever on the basis of echocardiographic findings of severe right ventricular eccentric hypertrophy, abnormally high systolic and diastolic pulmonary arterial pressures calculated by applying the modified Bernoulli equation to the tricuspid and pulmonary insufficiency peak velocities, and the absence of any underlying disease known to cause secondary pulmonary hypertension. The clinical abnormalities developed gradually, from exercise intolerance starting early in life to terminal right-sided congestive heart failure. Consistent histopathological findings were severe intimal and medial thickening of small arteries and arterioles that led to vascular obliteration.
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Affiliation(s)
- T M Glaus
- Division of Cardiology, Department of Small Animal Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
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137
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Humbert M, Morrell NW, Archer SL, Stenmark KR, MacLean MR, Lang IM, Christman BW, Weir EK, Eickelberg O, Voelkel NF, Rabinovitch M. Cellular and molecular pathobiology of pulmonary arterial hypertension. J Am Coll Cardiol 2004; 43:13S-24S. [PMID: 15194174 DOI: 10.1016/j.jacc.2004.02.029] [Citation(s) in RCA: 1090] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Accepted: 02/03/2004] [Indexed: 12/16/2022]
Abstract
Pulmonary arterial hypertension (PAH) has a multifactorial pathobiology. Vasoconstriction, remodeling of the pulmonary vessel wall, and thrombosis contribute to increased pulmonary vascular resistance in PAH. The process of pulmonary vascular remodeling involves all layers of the vessel wall and is complicated by cellular heterogeneity within each compartment of the pulmonary arterial wall. Indeed, each cell type (endothelial, smooth muscle, and fibroblast), as well as inflammatory cells and platelets, may play a significant role in PAH. Pulmonary vasoconstriction is believed to be an early component of the pulmonary hypertensive process. Excessive vasoconstriction has been related to abnormal function or expression of potassium channels and to endothelial dysfunction. Endothelial dysfunction leads to chronically impaired production of vasodilators such as nitric oxide and prostacyclin along with overexpression of vasoconstrictors such as endothelin (ET)-1. Many of these abnormalities not only elevate vascular tone and promote vascular remodeling but also represent logical pharmacological targets. Recent genetic and pathophysiologic studies have emphasized the relevance of several mediators in this condition, including prostacyclin, nitric oxide, ET-1, angiopoietin-1, serotonin, cytokines, chemokines, and members of the transforming-growth-factor-beta superfamily. Disordered proteolysis of the extracellular matrix is also evident in PAH. Future studies are required to find which if any of these abnormalities initiates PAH and which ones are best targeted to cure the disease.
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MESH Headings
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Humans
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Hypertension, Pulmonary/physiopathology
- Molecular Biology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- Pulmonary Artery/physiopathology
- Vascular Resistance/physiology
- Vasoconstriction/physiology
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Affiliation(s)
- Marc Humbert
- Service de Pneumologie et Réanimation Respiratoire, Centre des Maladies Vasculaires Pulmonaires, UPRES EA2705, Hôpital Antoine-Béclère, Université Paris-Sud, Clamart, France.
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138
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Abstract
Gender differences in pulmonary vascular diseases, as exemplified by primary pulmonary hypertension and scleroderma-related pulmonary hypertension, are not well-explained; however, in general terms, they seem to be related to a combination of genetic predispositions and gender-specific environmental triggers. More information is needed in both areas with respect to mechanisms of disease. More information also is needed about possible gender differences in disease presentation,course, and response to treatments.
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139
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Pietra GG, Capron F, Stewart S, Leone O, Humbert M, Robbins IM, Reid LM, Tuder RM. Pathologic assessment of vasculopathies in pulmonary hypertension. J Am Coll Cardiol 2004; 43:25S-32S. [PMID: 15194175 DOI: 10.1016/j.jacc.2004.02.033] [Citation(s) in RCA: 433] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Accepted: 02/03/2004] [Indexed: 11/21/2022]
Abstract
Pulmonary arterial hypertension (PAH) includes various forms of pulmonary hypertension of different etiology but similar clinical presentation and functional derangement. Histopathological vascular changes in all forms of PAH are qualitatively similar but with quantitative differences in the distribution and prevalence of pathological changes in various portions of the pulmonary vascular bed. The documentation of these topographic variations in the response of the pulmonary vasculature to injury may be important to understand the pathogenesis of the various subsets of PAH. To standardize the precise histopathological documentation of the pulmonary vasculopathy in PAH we propose a histopathological classification that includes both the predominant segment of the pulmonary vasculature affected and the possible coexistence of pathological changes in other vascular segments.
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Affiliation(s)
- Giuseppe G Pietra
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, Pennsylvania, USA.
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140
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Frid MG, Aldashev AA, Crossno JT, Jorgensen JM, Kale VA, Stenmark KR. Yin and Yang of an endothelial cell: from normal to the extreme in growth, secretion, and transdifferentiation capabilities. Paediatr Respir Rev 2004; 5 Suppl A:S253-7. [PMID: 14980281 DOI: 10.1016/s1526-0542(04)90048-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Maria G Frid
- Pediatric Critical Care, University of Colorado Health Sciences Center, Box B131, 4200 E 9th Avenue, Denver, CO 80262, USA.
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141
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Abstract
Blood vessels nourish organs with vital nutrients and oxygen and, thus, new vessels form when the embryo needs to grow or wounds are to heal. However, forming new blood vessels is a complex and delicate process, which, unfortunately, is often derailed. Thus, when insufficient vessels form, the tissue becomes ischaemic and stops to function adequately. Conversely, when vessels grow excessively, malignant and inflamed tissues grow faster. It is now becoming increasingly evident that abnormal vessel growth contributes to the pathogenesis of numerous malignant, ischaemic, inflammatory, infectious and immune disorders. With an in-depth molecular understanding, we should be better armamented to combat such angiogenic disorders in the future. That such therapeutic strategies might change the face of medicine is witnessed by initial evidence of success in the clinic.
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Affiliation(s)
- Peter Carmeliet
- Center for Transgene Technology and Gene Therapy, Flanders Interuniversitary Institute for Biotechnology, KU Leuven, Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.
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142
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Abstract
The pathogenesis of primary pulmonary hypertension (PPH) remains poorly understood. Molecular genetic studies have identified that mutations within the gene BMPR2 on the long arm of chromosome 2 underlie familial PPH. This review explores the significance of the PPH gene identification and examines additional genetic determinants, emphasizing the immediate implications for assessment and management of patients and their relatives.
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Affiliation(s)
- Richard C Trembath
- Division of Medical Genetics, Department of Medicine, Leicester University, Leicester, LE1 7RH, UK.
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143
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Abstract
Blood vessels constitute the first organ in the embryo and form the largest network in our body but, sadly, are also often deadly. When dysregulated, the formation of new blood vessels contributes to numerous malignant, ischemic, inflammatory, infectious and immune disorders. Molecular insights into these processes are being generated at a rapidly increasing pace, offering new therapeutic opportunities that are currently being evaluated.
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Affiliation(s)
- Peter Carmeliet
- Center for Transgene Technology and Gene Therapy, Flanders Interuniversitary Institute for Biotechnology, KULeuven, Campus Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium.
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144
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Abstract
Primary pulmonary hypertension (PPH) is a rare disorder characterised by raised pulmonary-artery pressure in the absence of secondary causes. Precapillary pulmonary arteries are affected by medial hypertrophy, intimal fibrosis, microthrombosis, and plexiform lesions. Most individuals present with dyspnoea or evidence of right heart failure. Echocardiography is the best non-invasive test to screen for suspected pulmonary hypertension. The discovery of mutations in the coding region of the gene for bone morphogenetic protein receptor 2 in patients with familial and sporadic PPH may help not only to elucidate pathogenesis but also to direct future treatment options. The pathogenesis is not completely understood, but recent investigations have revealed many possible candidate modifier genes. Without treatment, the disorder progresses in most cases to right heart failure and death. With current therapies such as epoprostenol, progression of disease is slowed, but not halted. Many promising new therapeutic options, including prostacyclin analogues, endothelin-1-receptor antagonists, and phosphodiesterase inhibitors, improve clinical function and haemodynamic measures and may prolong survival.
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Affiliation(s)
- James R Runo
- Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, T-1217 Medical Center North, Nashville, TN 37232-2650, USA
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145
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Abstract
Pulmonary arterial hypertension occurs in up to 15% of patients who have systemic sclerosis (SSc) and has a high mortality. It can develop as an isolated complication or secondary to pulmonary fibrosis. There have been significant advances in assessment and therapy for this complication. Patients should be screened regularly by Doppler-echocardiography and pulmonary function tests. Right heart catheterization provides important diagnostic and prognostic information. Drawing from experience with treating primary pulmonary hypertension, treatment in the context of SSc is now possible. Patients should receive oral anticoagulation and oxygen supplementation. Calcium channel blockers are rarely effective, but parenteral prostacyclin analogs improve functional capacity and pulmonary hemodynamics. The oral endothelin-receptor blocker, bosentan, was shown to be an effective therapy for established symptomatic pulmonary hypertension in SSc. The next major challenge is to improve diagnosis and treatment of early stage or presymptomatic pulmonary hypertension with the goal of preventing this important cause of premature SSc-related mortality.
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146
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Abstract
Pulmonary involvement is common in patients with portal hypertension and can manifest in diverse manners. Changes in pulmonary arterial resistance, manifesting either as the hepatopulmonary syndrome or portopulmonary hypertension (PPHTN), have been increasingly recognized in these patients in recent years. This review summarizes the clinicopathologic features, diagnostic criteria, as well as the latest concepts in the pathogenesis and management of PPHTN, which is defined as an elevated pulmonary artery pressure in the setting of an increased pulmonary vascular resistance and a normal wedge pressure in a patient with portal hypertension.
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Affiliation(s)
- Rohit Budhiraja
- Pulmonary and Critical Care Division, Department of Medicine, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA, USA
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147
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Michelakis ED, McMurtry MS, Sonnenberg B, Archer SL. The NO − K+ Channel Axis in Pulmonary Arterial Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 543:293-322. [PMID: 14713130 DOI: 10.1007/978-1-4419-8997-0_21] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The prognosis of patients with pulmonary arterial hypertension (PAH) is poor. Available therapies (Ca(++)-channel blockers, epoprostenol, bosentan) have limited efficacy or are expensive and associated with significant complications. PAH is characterized by vasoconstriction, thrombosis in-situ and vascular remodeling. Endothelial-derived nitric oxide (NO) activity is decreased, promoting vasoconstriction and thrombosis. Voltage-gated K+ channels (Kv) are downregulated, causing depolarization, Ca(++)-overload and PA smooth muscle cell (PASMC) contraction and proliferation. Augmenting the NO and Kv pathways should cause pulmonary vasodilatation and regression of PA remodeling. Several inexpensive oral treatments may be able to enhance the NO axis and/or K+ channel expression/function and selectively decrease pulmonary vascular resistance (PVR). Oral L-Arginine, NOS' substrate, improves NO synthesis and functional capacity in humans with PAH. Most of NO's effects are mediated by cyclic guanosine-monophosphate (c-GMP). cGMP causes vasodilatation by activating K+ channels and lowering cytosolic Ca++. Sildenafil elevates c-GMP levels by inhibiting type-5 phosphodiesterase, thereby opening BK(Ca). channels and relaxing PAs. In PAH, sildenafil (50 mg-po) is as effective and selective a pulmonary vasodilator as inhaled NO. These benefits persist after months of therapy leading to improved functional capacity. 3) Oral Dichloroacetate (DCA), a metabolic modulator, increases expression/function of Kv2.1 channels and decreases remodeling and PVR in rats with chronic-hypoxic pulmonary hypertension, partially via a tyrosine-kinase-dependent mechanism. These drugs appear safe in humans and may be useful PAH therapies, alone or in combination.
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Affiliation(s)
- Evangelos D Michelakis
- University of Alberta Hospitals, 2C2 Walker C McKenzie Health Sciences, Centre, Edmonton, Canada
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148
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Abstract
Primary pulmonary hypertension (PPH) is a serious pulmonary vascular disease occurring mostly in adult women. Although its occurrence in families was reported within a few years after the original clinical report, PPH was formerly believed rarely to have a genetic basis. Recent progress has not only clarified a basic molecular mechanism for PPH in families, but has also identified mutations of the same gene in many sporadic PPH patients, suggesting that its basis is commonly genetic. Extensive investigations in many centers are now in progress to provide a complete dissection of all the pathogenetic mechanisms of PPH.
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Affiliation(s)
- James E Loyd
- Department of Pulmonary and Critical Care Medicine, Vanderbilt Medical Center North, Nashville, TN 37232, USA.
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149
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Jeffery TK, Morrell NW. Molecular and cellular basis of pulmonary vascular remodeling in pulmonary hypertension. Prog Cardiovasc Dis 2002; 45:173-202. [PMID: 12525995 DOI: 10.1053/pcad.2002.130041] [Citation(s) in RCA: 221] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Clinical pulmonary hypertension is characterized by a sustained elevation in pulmonary arterial pressure. Pulmonary vascular remodeling involves structural changes in the normal architecture of the walls of pulmonary arteries. The process of vascular remodeling can occur as a primary response to injury, or stimulus such as hypoxia, within the resistance vessels of the lung. Alternatively, the changes seen in more proximal vessels may arise secondary to a sustained increase in intravascular pressure. To withstand the chronic increase in intraluminal pressure, the vessel wall becomes thickened and stronger. This "armouring" of the vessel wall with extra-smooth muscle and extracellular matrix leads to a decrease in lumen diameter and reduced capacity for vasodilatation. This maladaptive response results in increased pulmonary vascular resistance and consequently, sustained pulmonary hypertension. The process of pulmonary vascular remodeling involves all layers of the vessel wall and is complicated by the finding that cellular heterogeneity exists within the traditional compartments of the vascular wall: intima, media, and adventitia. In addition, the developmental stage of the organism greatly modifies the response of the pulmonary circulation to injury. This review focuses on the latest advances in our knowledge of these processes as they relate to specific forms of pulmonary hypertension and particularly in the light of recent genetic studies that have identified specific pathways involved in the pathogenesis of severe pulmonary hypertension.
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Affiliation(s)
- T K Jeffery
- Respiratory Medicine Unit, Department of Medicine, Addenbrooke's Hospital, University of Cambridge School of Clinical Medicine, Cambridge, UK
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150
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Abstract
Severe pulmonary hypertension is a fatal condition associated with marked alterations of the cellular components of pulmonary arteries. In this review, we discuss the component of endothelial cell proliferation present in pulmonary arteries in patients with severe pulmonary hypertension. Because these proliferated endothelial cells exhibit markers of angiogenesis, we have named this process as "disordered or misguided angiogenesis." We also discuss the recent evidence that germline or somatic inactivating mutations in tumor suppressor or proapoptotic genes may play a significant role in the abnormal proliferation of pulmonary endothelial cells. The unraveling of the pathobiology of severe pulmonary hypertension may lead us to novel therapies and approaches to better diagnose the disease.
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Affiliation(s)
- Rubin M Tuder
- Division of Cardiopulmonary Pathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA.
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