Al proliferation of the upstream bronchial arteries. Potential mechanisms include growth factor transit from ischemic parenchyma with fluid movement, inflammatory cell migration from ischemic parenchyma or recruitment through the perfusing artery, and a paracrine effect of cells within the left bronchus, the niche where arteriogenesis takes place. The goal of this study was focused on collecting information concerning each of these three potential mechanisms to better understand the early initiators of bronchial arteriogenesis. Angiogenesis in the lung has been shown to be induced largely during inflammatory states [3,17,18]. Unlike other organs where tissue hypoxia plays the predominant role in inducing release of growth factors, the Ll Em-myc) Mtap+/+mouse 370 322 329 331 336 353 309 343 369 341 320CD19 + + + + + 2 + + + + + +AA4.1 + + + + + 2 + + + + + +PNA ++ ++ ++ ++ ++ 2 ++ ++ ++ ++ ++ ++IgM 2 +/2 ++ ++ ++ 2 2 2 2 +/2 ++ ++IgD 2 2 +/2 2 2 nd 2 2 2 2 +/2 +/CD ventilated lung appears to be most sensitive to inflammatory cell burden. Others have shown that treatment with anti-inflammatory agents can limit angiogenesis [19]. The synthetic glucocorticoid dexamethasone has been shown to modulate, among several signaling molecules, pro-inflammatory cytokines such as CCL2 (MCP-1) and sub-members of the CXCL8 family, of which the CINC proteins are members [20,21]. In the present study we also sought to validate the effectiveness of dexamethasone therapy to negatively modulate the inflammatory response in the ischemic lung and to probe the mechanism of growth factor access to large bronchial vessels. Our results confirm the presence of CXC chemokines within bronchoAcute Ischemia and CXC Chemokinesalveolar lavage fluid as well as within bronchial tissue. Despite significant reduction in lung injury and inflammation with dexamethasone treatment, chemokine expression within the bronchial tissue as well as angiogenesis were not affected. Our results suggest that early changes within bronchial tissue itself contribute to subsequent neovascularization during pulmonary ischemia.Methods AnimalsOur animal protocol was approved by the Johns Hopkins Animal Care and Use Committee (Protocol # 298690-60-5 web RA11M47). Sprague-Dawley male rats (125?50 g; Harlan, Indianapolis, IN) were anesthetized, intubated, and ventilated (90 breaths/min, 8 ml/kg/breath) with an anesthetic-gas mixture (3 isoflurane in O2). Left pulmonary artery ligation (LPAL) was performed as previously described [12]. After left lateral thoracotomy between the fourth and the fifth intercostal space, the left pulmonary artery was ligated. The thoracotomy was closed and bupivicaine (2 mg/ kg) was injected at the incision site for analgesia. After closing the skin incision with methyl acrylamide adhesive, buprenorphine (0.05 mg/kg ip) was given for additional analgesia, the rat was removed from the ventilator, extubated, and allowed to recover. After specified times following LPAL, anesthetized rats were euthanized by exsanguination.(Epcam/G8.8 clone, Biolegend, San Diego,CA; Gro-beta #ab97777, Abcam,, Cambridge, MA; CXCR2 #ab14935, Abcam, and RECA-1 # MCA970GA, Serotec, Raleigh, NC. After washing, sections were incubated with biotin anti-rabbit antibody followed by streptavidin labeled with Alexa Fluor 488, Alexa Fluor 594 and counterstained with DAPI (all from Invitrogen). Tissue stained without primary antibody was used as control. Sections were visualized and photographed using an Olympus IX51 microscope and SensiCam high performance digital camera (Cooke, Auburn Hills, 1676428 MI).Bronchial endothelial cell proliferationMorphometric assessment of bronchial endothelial cell proliferation was determined as an index of early angiogenesi.Al proliferation of the upstream bronchial arteries. Potential mechanisms include growth factor transit from ischemic parenchyma with fluid movement, inflammatory cell migration from ischemic parenchyma or recruitment through the perfusing artery, and a paracrine effect of cells within the left bronchus, the niche where arteriogenesis takes place. The goal of this study was focused on collecting information concerning each of these three potential mechanisms to better understand the early initiators of bronchial arteriogenesis. Angiogenesis in the lung has been shown to be induced largely during inflammatory states [3,17,18]. Unlike other organs where tissue hypoxia plays the predominant role in inducing release of growth factors, the ventilated lung appears to be most sensitive to inflammatory cell burden. Others have shown that treatment with anti-inflammatory agents can limit angiogenesis [19]. The synthetic glucocorticoid dexamethasone has been shown to modulate, among several signaling molecules, pro-inflammatory cytokines such as CCL2 (MCP-1) and sub-members of the CXCL8 family, of which the CINC proteins are members [20,21]. In the present study we also sought to validate the effectiveness of dexamethasone therapy to negatively modulate the inflammatory response in the ischemic lung and to probe the mechanism of growth factor access to large bronchial vessels. Our results confirm the presence of CXC chemokines within bronchoAcute Ischemia and CXC Chemokinesalveolar lavage fluid as well as within bronchial tissue. Despite significant reduction in lung injury and inflammation with dexamethasone treatment, chemokine expression within the bronchial tissue as well as angiogenesis were not affected. Our results suggest that early changes within bronchial tissue itself contribute to subsequent neovascularization during pulmonary ischemia.Methods AnimalsOur animal protocol was approved by the Johns Hopkins Animal Care and Use Committee (Protocol # RA11M47). Sprague-Dawley male rats (125?50 g; Harlan, Indianapolis, IN) were anesthetized, intubated, and ventilated (90 breaths/min, 8 ml/kg/breath) with an anesthetic-gas mixture (3 isoflurane in O2). Left pulmonary artery ligation (LPAL) was performed as previously described [12]. After left lateral thoracotomy between the fourth and the fifth intercostal space, the left pulmonary artery was ligated. The thoracotomy was closed and bupivicaine (2 mg/ kg) was injected at the incision site for analgesia. After closing the skin incision with methyl acrylamide adhesive, buprenorphine (0.05 mg/kg ip) was given for additional analgesia, the rat was removed from the ventilator, extubated, and allowed to recover. After specified times following LPAL, anesthetized rats were euthanized by exsanguination.(Epcam/G8.8 clone, Biolegend, San Diego,CA; Gro-beta #ab97777, Abcam,, Cambridge, MA; CXCR2 #ab14935, Abcam, and RECA-1 # MCA970GA, Serotec, Raleigh, NC. After washing, sections were incubated with biotin anti-rabbit antibody followed by streptavidin labeled with Alexa Fluor 488, Alexa Fluor 594 and counterstained with DAPI (all from Invitrogen). Tissue stained without primary antibody was used as control. Sections were visualized and photographed using an Olympus IX51 microscope and SensiCam high performance digital camera (Cooke, Auburn Hills, 1676428 MI).Bronchial endothelial cell proliferationMorphometric assessment of bronchial endothelial cell proliferation was determined as an index of early angiogenesi.
