ABSTRACT
BACKGROUND: There is increasing in vitro evidence to support a role for vascular endothelial growth factor (VEGF), a major regulator of angiogenesis, as a mediator of fibrosis associated with neovascularization. OBJECTIVE: We tested the hypothesis that VEGF is involved both in increased airway mucosal vascularity and in the subepithelial fibrosis of asthmatic patients. METHODS: Bronchial biopsies were performed in 24 asthmatic patients and eight healthy controls. Immunostaining, using computerized image analysis, was performed using monoclonal antibodies against VEGF(+) cells, type IV collagen, to outline the basement membrane thickness, and tryptase and EG2, to identify mast cells and eosinophils, respectively. RESULTS: The counts of VEGF(+) cells (P<0.05), mast cells and EG2(+) cells (both P<0.01) were higher in asthmatics than in controls. The number of vessels, the vascular area in the lamina propria, and the basement membrane thickness were significantly higher in asthmatics than in healthy volunteers (P<0.01). Moreover, in asthmatic patients, the number of VEGF(+) cells was significantly related to the number of vessels (P<0.01), to mast cells (P<0.01) and to basement membrane thickness (P<0.01). A colocalization study also revealed that mast cells were a relevant cellular source of VEGF. High doses of inhaled fluticasone propionate significantly reduced VEGF(+) cells (P<0.05), vessel number (P<0.05), vascular area (P<0.05) and basement membrane thickness (P<0.05) in a subgroup of asthmatic patients. CONCLUSIONS: This study shows that VEGF, in addition to being involved in the vascular component of airway remodelling, may play a role in the thickening of the basement membrane in asthma.
Subject(s)
Asthma/pathology , Bronchi/pathology , Vascular Endothelial Growth Factor A/metabolism , Administration, Inhalation , Adult , Androstadienes/administration & dosage , Asthma/drug therapy , Asthma/metabolism , Basement Membrane/blood supply , Basement Membrane/metabolism , Basement Membrane/pathology , Biopsy/methods , Bronchi/blood supply , Bronchi/metabolism , Bronchodilator Agents/administration & dosage , Bronchoscopy/methods , Cell Count , Eosinophils/metabolism , Eosinophils/pathology , Female , Fibrosis , Fluticasone , Humans , Male , Mast Cells/metabolism , Mast Cells/pathology , Mucous Membrane/blood supply , Mucous Membrane/metabolism , Mucous Membrane/pathology , Up-Regulation/physiologyABSTRACT
Parathyroid hormone-related protein (PTHrP) is critical for normal mammary development and is overexpressed by breast cancers. PTHrP is a peptide hormone that undergoes extensive post-translational processing, and PTHrP(38-94)-amide is one of the mature secretory forms of the peptide. In this study, we explored the effect of PTHrP(38-94)-amide in a panel of six breast cancer cell lines "in vitro" and in MDA-MB231 cells "in vivo" specifically examining cell viability, proliferation, invasiveness, and growth in nude mice. PTHrP(38-94)-amide markedly inhibited proliferation and also caused striking toxicity and accelerated cell death in breast cancer cells. In addition, direct injection of PTHrP(38-94)-amide into MDA-MB231 breast cancer cells passaged in immunodeficient mice produced a marked reduction in tumor growth. These studies (i) indicate breast cancer cells are one of the few tissues in which specific effects of midregion PTHrP have been established to date, (ii) support a role for midregion secretory forms of PTHrP in modulating not only normal but also pathological mammary growth and differentiation, (iii) add further evidence for the existence of a specific midregion PTHrP receptor, and (iv) provide a novel molecule for modeling of small molecule analogues that may have anti-breast cancer effects.
