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Recipient iNOS but not eNOS deficiency reduces luminal narrowing in tracheal allografts.

Minamoto K, Pinsky DJ - J. Exp. Med. (2002)

Bottom Line: In contrast, allografts in iNOS(-/-) recipients exhibited reductions in local expression of proinflammatory chemokines and cytokines, graft T cell recruitment and apoptosis, and luminal obliteration (29 +/- 2%, P < 0.05 vs.WT allografts).Recipient eNOS deficiency, however, suppressed neither chemokine expression, lymphocyte infiltration, nor airway occlusion (54 +/- 2%).

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.

ABSTRACT
Chronic airway rejection is characterized by prolonged inflammation, epithelial damage, and eventual luminal obliterative bronchiolitis (OB). In cardiac allografts, the inducible nitric oxide synthase (iNOS) promotes acute rejection but paradoxically reduces neointimal formation, the hallmark of chronic rejection. The specific roles of NOS isoforms in modulating lymphocyte traffic and airway rejection are not known. Using a double lumen mouse tracheal transplant model, tracheal grafts from B10.A (allo) or C57BL/6J (iso) mice were transplanted into cyclosporine-treated wild-type (WT) iNOS(-/-) or endothelial NOS (eNOS)(-/-) recipients. OB was observed in WT tracheal allografts at 3 weeks (53 +/- 2% luminal occlusion vs. 17 +/- 1% for isografts, P < 0.05) with sites of obstructive lesion formation coinciding with areas of CD3(+) CD8(+) T cell-rich lymphocytic bronchitis. In contrast, allografts in iNOS(-/-) recipients exhibited reductions in local expression of proinflammatory chemokines and cytokines, graft T cell recruitment and apoptosis, and luminal obliteration (29 +/- 2%, P < 0.05 vs. WT allografts). Recipient eNOS deficiency, however, suppressed neither chemokine expression, lymphocyte infiltration, nor airway occlusion (54 +/- 2%). These data demonstrate that iNOS exacerbates luminal obliteration of airway allografts in contrast with the known suppression by iNOS of cardiac allograft vasculopathy. Because iNOS(-/-) airways transplanted into WT allograft hosts are not protected from rejection, these data suggest that iNOS expressed by graft-infiltrating leukocytes exerts the dominant influence on airway rejection.

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(A) New model of murine tracheal transplantation. The graft can fulfill its function as an airway by placing the proximal and distal graft anastomoses in the native trachea. This environment allows epithelium in the graft to be exposed to air and drain mucous through the anastomosis. Arrow, tracheal graft; arrowhead, native trachea. (B) Immunostaining for vWf in an allograft from a WT recipient. Arrows, anti–vWf-reactive capillaries. (C) Representative Verhoeff's-Van Gieson staining of transverse sections (low power magnification for a–d, high power magnification for e–h) through WT allografts (right side) with native trachea (left side) revealing the time course of the rejection process. After tracheal transplant (0 wk; a and e), mononuclear cells accumulated in the EL as well as SEL at 3 wk (b and f), with subsequent diminution by 6 wk (c and g). After 6 wk, epithelial cells were observed to dissociate from the basement membrane (BM). By 10 wk (d and h), epithelium appeared flattened with loss of ciliary structures and the subepithelial space was thickened with substantial collagen deposition. The time course of luminal occlusive lesions in the EL and SEL shown in D demonstrates that the intensity of the infiltrate corresponds with subsequent graft luminal (GL) occlusion. Comparing luminal patency with isografts, which exhibited near-complete patency, allografts were maximally occluded 3 wk after transplantation. n = 4 for each group; *, P < 0.05; bar, 50 μm.
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fig1: (A) New model of murine tracheal transplantation. The graft can fulfill its function as an airway by placing the proximal and distal graft anastomoses in the native trachea. This environment allows epithelium in the graft to be exposed to air and drain mucous through the anastomosis. Arrow, tracheal graft; arrowhead, native trachea. (B) Immunostaining for vWf in an allograft from a WT recipient. Arrows, anti–vWf-reactive capillaries. (C) Representative Verhoeff's-Van Gieson staining of transverse sections (low power magnification for a–d, high power magnification for e–h) through WT allografts (right side) with native trachea (left side) revealing the time course of the rejection process. After tracheal transplant (0 wk; a and e), mononuclear cells accumulated in the EL as well as SEL at 3 wk (b and f), with subsequent diminution by 6 wk (c and g). After 6 wk, epithelial cells were observed to dissociate from the basement membrane (BM). By 10 wk (d and h), epithelium appeared flattened with loss of ciliary structures and the subepithelial space was thickened with substantial collagen deposition. The time course of luminal occlusive lesions in the EL and SEL shown in D demonstrates that the intensity of the infiltrate corresponds with subsequent graft luminal (GL) occlusion. Comparing luminal patency with isografts, which exhibited near-complete patency, allografts were maximally occluded 3 wk after transplantation. n = 4 for each group; *, P < 0.05; bar, 50 μm.

Mentions: Recipient mice were similarly anesthetized. After shaving a small area on the anterior neck and preparing with iodine alcohol solution, the whole trachea was exposed and two round buttons of tissue were removed (matched in size and aligned with the open ends of the donor tracheal segment; see Fig. 1 A). The distal recipient orifice was positioned in the sixth intercartilaginous space and the proximal orifice was placed immediately subjacent to the cricoid cartilage area. Distal and proximal tracheal anastomoses were performed end to side using continuous 10-0 polypropylene sutures. Surgical wounds were repaired with a two-layer closer technique (anterior cervical muscles and skin). This new model of tracheal transplantation permits airflow through the tracheal lumen as well as the elimination of inspissated mucous and is therefore more likely to be physiologic than the standard model (38, 39) in which a tracheal segment is transplanted into subcutaneous tissue in the recipient's back.


Recipient iNOS but not eNOS deficiency reduces luminal narrowing in tracheal allografts.

Minamoto K, Pinsky DJ - J. Exp. Med. (2002)

(A) New model of murine tracheal transplantation. The graft can fulfill its function as an airway by placing the proximal and distal graft anastomoses in the native trachea. This environment allows epithelium in the graft to be exposed to air and drain mucous through the anastomosis. Arrow, tracheal graft; arrowhead, native trachea. (B) Immunostaining for vWf in an allograft from a WT recipient. Arrows, anti–vWf-reactive capillaries. (C) Representative Verhoeff's-Van Gieson staining of transverse sections (low power magnification for a–d, high power magnification for e–h) through WT allografts (right side) with native trachea (left side) revealing the time course of the rejection process. After tracheal transplant (0 wk; a and e), mononuclear cells accumulated in the EL as well as SEL at 3 wk (b and f), with subsequent diminution by 6 wk (c and g). After 6 wk, epithelial cells were observed to dissociate from the basement membrane (BM). By 10 wk (d and h), epithelium appeared flattened with loss of ciliary structures and the subepithelial space was thickened with substantial collagen deposition. The time course of luminal occlusive lesions in the EL and SEL shown in D demonstrates that the intensity of the infiltrate corresponds with subsequent graft luminal (GL) occlusion. Comparing luminal patency with isografts, which exhibited near-complete patency, allografts were maximally occluded 3 wk after transplantation. n = 4 for each group; *, P < 0.05; bar, 50 μm.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2193988&req=5

fig1: (A) New model of murine tracheal transplantation. The graft can fulfill its function as an airway by placing the proximal and distal graft anastomoses in the native trachea. This environment allows epithelium in the graft to be exposed to air and drain mucous through the anastomosis. Arrow, tracheal graft; arrowhead, native trachea. (B) Immunostaining for vWf in an allograft from a WT recipient. Arrows, anti–vWf-reactive capillaries. (C) Representative Verhoeff's-Van Gieson staining of transverse sections (low power magnification for a–d, high power magnification for e–h) through WT allografts (right side) with native trachea (left side) revealing the time course of the rejection process. After tracheal transplant (0 wk; a and e), mononuclear cells accumulated in the EL as well as SEL at 3 wk (b and f), with subsequent diminution by 6 wk (c and g). After 6 wk, epithelial cells were observed to dissociate from the basement membrane (BM). By 10 wk (d and h), epithelium appeared flattened with loss of ciliary structures and the subepithelial space was thickened with substantial collagen deposition. The time course of luminal occlusive lesions in the EL and SEL shown in D demonstrates that the intensity of the infiltrate corresponds with subsequent graft luminal (GL) occlusion. Comparing luminal patency with isografts, which exhibited near-complete patency, allografts were maximally occluded 3 wk after transplantation. n = 4 for each group; *, P < 0.05; bar, 50 μm.
Mentions: Recipient mice were similarly anesthetized. After shaving a small area on the anterior neck and preparing with iodine alcohol solution, the whole trachea was exposed and two round buttons of tissue were removed (matched in size and aligned with the open ends of the donor tracheal segment; see Fig. 1 A). The distal recipient orifice was positioned in the sixth intercartilaginous space and the proximal orifice was placed immediately subjacent to the cricoid cartilage area. Distal and proximal tracheal anastomoses were performed end to side using continuous 10-0 polypropylene sutures. Surgical wounds were repaired with a two-layer closer technique (anterior cervical muscles and skin). This new model of tracheal transplantation permits airflow through the tracheal lumen as well as the elimination of inspissated mucous and is therefore more likely to be physiologic than the standard model (38, 39) in which a tracheal segment is transplanted into subcutaneous tissue in the recipient's back.

Bottom Line: In contrast, allografts in iNOS(-/-) recipients exhibited reductions in local expression of proinflammatory chemokines and cytokines, graft T cell recruitment and apoptosis, and luminal obliteration (29 +/- 2%, P < 0.05 vs.WT allografts).Recipient eNOS deficiency, however, suppressed neither chemokine expression, lymphocyte infiltration, nor airway occlusion (54 +/- 2%).

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.

ABSTRACT
Chronic airway rejection is characterized by prolonged inflammation, epithelial damage, and eventual luminal obliterative bronchiolitis (OB). In cardiac allografts, the inducible nitric oxide synthase (iNOS) promotes acute rejection but paradoxically reduces neointimal formation, the hallmark of chronic rejection. The specific roles of NOS isoforms in modulating lymphocyte traffic and airway rejection are not known. Using a double lumen mouse tracheal transplant model, tracheal grafts from B10.A (allo) or C57BL/6J (iso) mice were transplanted into cyclosporine-treated wild-type (WT) iNOS(-/-) or endothelial NOS (eNOS)(-/-) recipients. OB was observed in WT tracheal allografts at 3 weeks (53 +/- 2% luminal occlusion vs. 17 +/- 1% for isografts, P < 0.05) with sites of obstructive lesion formation coinciding with areas of CD3(+) CD8(+) T cell-rich lymphocytic bronchitis. In contrast, allografts in iNOS(-/-) recipients exhibited reductions in local expression of proinflammatory chemokines and cytokines, graft T cell recruitment and apoptosis, and luminal obliteration (29 +/- 2%, P < 0.05 vs. WT allografts). Recipient eNOS deficiency, however, suppressed neither chemokine expression, lymphocyte infiltration, nor airway occlusion (54 +/- 2%). These data demonstrate that iNOS exacerbates luminal obliteration of airway allografts in contrast with the known suppression by iNOS of cardiac allograft vasculopathy. Because iNOS(-/-) airways transplanted into WT allograft hosts are not protected from rejection, these data suggest that iNOS expressed by graft-infiltrating leukocytes exerts the dominant influence on airway rejection.

Show MeSH
Related in: MedlinePlus