[Show abstract][Hide abstract] ABSTRACT: In chronic obstructive pulmonary disease (COPD), decreased progenitor cells and impairment of systemic vascular function have been suggested to confer higher cardiovascular risk. The origin of these changes and their relationship with alterations in the pulmonary circulation are unknown.
PLoS ONE 01/2014; 9(8):e106163. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cigarette smoke (CS) and chronic hypoxia (CH) can produce pulmonary hypertension. Similarities and differences between both exposures and their interaction have not been explored. The aim of the present study was to investigate the effects of CS and CH, as single factors or in combination, on the pulmonary circulation in the guinea pig. 51 guinea pigs were exposed to CS for 12 weeks and 32 were sham-exposed. 50% of the animals in each group were additionally exposed to CH for the final 2 weeks. We measured pulmonary artery pressure (P(pa)), and the weight ratio between the right ventricle (RV) and left ventricle plus the septum. Pulmonary artery contractility in response to noradrenaline (NA), endothelium-dependent vasodilatation and distensibility were evaluated in organ bath chambers. The number of small intrapulmonary vessels showing immunoreactivity to smooth muscle (SM) α-actin and double elastic laminas was assessed microscopically. CS and CH induced similar increases of P(pa) and RV hypertrophy (p<0.05 for both), effects that were further enhanced when both factors were combined. CH increased the contractility to NA (p<0.01) and reduced the distensibility (p<0.05) of pulmonary arteries. Animals exposed to CS showed an increased number of small vessels with positive immunoreactivity to SM α-actin (p<0.01) and those exposed to CH a greater proportion of vessels with double elastic laminas (p<0.05). We conclude that CH amplifies the detrimental effects of CS on the pulmonary circulation by altering the mechanical properties of pulmonary arteries and enhancing the remodelling of pulmonary arterioles.
European Respiratory Journal 02/2011; 38(3):617-27. · 6.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Endothelial progenitor cells (EPC) have been shown to repair pulmonary endothelium, although they can also migrate into the arterial intima and differentiate into smooth muscle-like (mesenchymal) cells contributing to intimal hyperplasia. The molecular mechanisms by which this process proceeds have not been fully elucidated. Here, we study whether genes involved in the endothelial-to-mesenchymal transition (EnMT) may contribute to the mesenchymal phenotype acquisition of EPC and we evaluate whether transforming growth factor β1 (TGFβ1) is involved in this process.
Our results show that co-culture of EPC with smooth muscle cells (SMC) increases the expression of the mesenchymal cell markers α-smooth muscle actin, sm22-α, and myocardin, and decreases the expression of the endothelial cell marker CD31. In the same conditions, we also observed a concomitant increase in the gene expression of the EnMT-related transcription factors: slug, snail, zeb1, and endothelin-1. This indicates that mesenchymal phenotype acquisition occurred through an EnMT-like process. Inhibition of TGFβ receptor I (TGFβRI) downregulated snail gene expression, blocked the EnMT, and facilitated the differentiation of EPC to the endothelial cell lineage. Furthermore, TGFβRI inhibition decreased migration of EPC stimulated by SMC without affecting their functionality and adhesion capacity.
These results indicate that EPC may differentiate into SMC-like cells through an EnMT-like process and that TGFβI plays an important role in the fate of EPC.
Cardiovascular Research 12/2010; 88(3):502-11. · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cigarette smoking may contribute to pulmonary hypertension in chronic obstructive pulmonary disease by altering the structure and function of pulmonary vessels at early disease stages. The objectives of this study were to evaluate the effects of long-term exposure to cigarette smoke on endothelial function and smooth muscle-cell proliferation in pulmonary arteries of guinea pigs.
19 male Hartley guinea pigs were exposed to the smoke of 7 cigarettes/day, 5 days/week, for 3 and 6 months. 17 control guinea pigs were sham-exposed for the same periods. Endothelial function was evaluated in rings of pulmonary artery and aorta as the relaxation induced by ADP. The proliferation of smooth muscle cells and their phenotype in small pulmonary vessels were evaluated by immunohistochemical expression of alpha-actin and desmin. Vessel wall thickness, arteriolar muscularization and emphysema were assessed morphometrically. The expression of endothelial nitric oxide synthase (eNOS) was evaluated by Real Time-PCR.
Exposure to cigarette smoke reduced endothelium-dependent vasodilatation in pulmonary arteries (ANOVA p < 0.05) but not in the aorta. Endothelial dysfunction was apparent at 3 months of exposure and did not increase further after 6 months of exposure. Smoke-exposed animals showed proliferation of poorly differentiated smooth muscle cells in small vessels (p < 0.05) after 3 months of exposure. Prolonged exposure resulted in full muscularization of small pulmonary vessels (p < 0.05), wall thickening (p < 0.01) and increased contractility of the main pulmonary artery (p < 0.05), and enlargement of the alveolar spaces. Lung expression of eNOS was decreased in animals exposed to cigarette smoke.
In the guinea pig, exposure to cigarette smoke induces selective endothelial dysfunction in pulmonary arteries, smooth muscle cell proliferation in small pulmonary vessels and reduced lung expression of eNOS. These changes appear after 3 months of exposure and precede the development of pulmonary emphysema.
Respiratory research 09/2009; 10:76. · 3.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Studies in pulmonary arteries (PA) of patients with chronic obstructive pulmonary disease (COPD) suggest that bone marrow-derived endothelial progenitor cells (CD133(+)) may infiltrate the intima and differentiate into smooth muscle cells (SMC). This study aimed to evaluate the plasticity of CD133(+) cells to differentiate into SMC and endothelial cells (EC) in both cell culture and human isolated PA.
Plasticity of granulocyte-colony stimulator factor (G-CSF)-mobilized peripheral blood CD133(+) cells was assessed in co-cultures with primary lines of human PA endothelial cells (PAEC) or SMC (PASMC) and in isolated human PA. We also evaluated if the phenotype of differentiated progenitor cells was acquired by fusion or differentiation.
The in vitro studies demonstrated CD133(+) cells may acquire the morphology and phenotype of the cells they were co-cultured with. CD133(+) cells co-incubated with human isolated PA were able to migrate into the intima and differentiate into SMC. Progenitor cell differentiation was produced without fusion with mature cells.
We provide evidence of plasticity of CD133(+) cells to differentiate into both endothelial cells and SMC, reinforcing the idea of their potential role in the remodeling process of PA in COPD. This process was conducted by transdifferentiation and not by cell fusion.
Cardiovascular Research 01/2008; 76(3):517-27. · 5.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Vascular progenitor cells (VPC) have shown in vitro and in vivo their ability to differentiate into endothelial cells (EC). Some evidence suggests that the plasticity of these cells to differentiate into other cell types might contribute not only to angiogenesis but also to perpetuate vascular lesions. Studies done in pulmonary arteries (PA) of patients with COPD have demonstrated the presence of VPC infiltrating the intima. Since intimal thickening is mainly constituted by smooth muscle cells (SMC), we asked whether VPC could play a role in wall thickening. Accordingly, the objective was to evaluate in vitro the plasticity of VPC to differentiate into SMC and EC of human PA. G-CSF-mobilized peripheral blood CD133+ cells from a commercial primary line were expanded and labelled with acetylated-LDL-DiI for tracking cell purposes. Then, cells were co-cultured with commercial primary lines of human PA EC or SMC (n = 3). As control, CD133+ cells were cultured alone, with minimal medium with or without VEGF (50ng·ml–1). After 6 and 12 days of growth, the phenotype of cultures was characterized by immunofluorescence with: lectin, -actin and CD31. Cells were also evaluated morphologically. After 6 days, VPC acquired the morphology and the phenotype of the cells with which they were co-cultured, EC (lectin+, CD31+, alpha-actin-) or SMC (alpha-actin+, lectin-, CD31-). VPC cultured 12 days alone or with VEGF did not acquire typical morphology and markers of mature EC or SMC of PA. We conclude that VPC have the potential to differentiate in vitro into SMC, and that this plasticity could contribute to perpetuate pulmonary vascular remodelling in COPD.