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ROLE OF ALLOGENIC IMMUNE RESPONSE IN THE RECRUITMENT OF HOST-DERIVED SMOOTH MUSCLE CELLS IN TRANSPLANT ARTERIOSCLEROSIS
Poster Abstracts / Cardiovascular Pathology 13 (2004) S80–S138 CAD) and graft failure suggesting that a proinflammatory microenvironment within the allografts plays a major role in patient’s outcome. We investigated whether high-sensitivity CRP (hsCRP) levels were associated with other proinflammatory molecules such as tumor necrosis factor-a (TNF-a), interleukin-1b (IL-1b) and interferon-g (IFN-g), known to activate endothelium, and with increased levels of intercellular adhesion molecule-1 (ICAM-1). Methods: hsCRP, TNF-a, IL-1b, IFN-g and soluble ICAM-1 levels were determined using ELISA in serial serum samples (Median: 7; Range: 1 – 7) obtained during the first 3 months post-transplant from 120 patients. Patients with different levels of hsCRP were compared for the association with the different cytokine levels and levels of soluble ICAM-1. Results: Patients ( N = 120) were grouped according to the hsCRP percentile levels. Groups under the 25th percentile (< 1.1 mg/L), between the 25th and 75th percentiles (1.1 – 6.2 mg/L) and over the 75th percentile ( > 6.2 mg/L) were compared to evaluate differences in cytokine levels and soluble ICAM-1. A significant association was found between hsCRP levels and TNF-a ( p = .01) and soluble ICAM-1 ( p < .01). No significant association was found between hsCRP levels and IL-1b ( p = .153) or IFN-g ( p = .38). Patients with increased levels of hsCRP had concomitantly increased levels of serum TNF-a and soluble ICAM-1. hsCRP and soluble ICAM1 levels were associated with development and severity of Tx-CAD and with allograft failure. Conclusions: The present data show the association between hsCRP levels and TNF-a and between hsCRP and soluble ICAM-1 in heart transplant patients. Further studies are needed in order to demonstrate if the role of hsCRP on the activation of endothelium within the transplanted heart is mediated through increased expression of TNF-a. All these processes may eventually lead to development of Tx-CAD and graft failure. Funded by: Showalter Foundation, Indianapolis, IN
P379 C-REACTIVE PROTEIN AND MICROVASCULAR PROTHROMBOGENICITY IN HEART TRANSPLANT PATIENTS. Carlos Labarrere, Hector DiCarlo, Miguel Ortiz, Colin Terry, Douglas Pitts, David Hormuth. Methodist Research Institute, Clarian Health Partners, Indianapolis, IN, Clarian Health Transplant Center, Clarian Health Partners, Indianapolis, IN Introduction: Increased serum levels of C-reactive protein (CRP) and activation of endothelium are risk factors for transplant coronary artery disease (Tx-CAD) and graft failure, suggesting that a proinflammatory microenvironment within the allografts plays a significant role in patient’s outcome. Since endothelial activation is associated with a procoagulant status in the microvasculature, we investigated whether elevated levels of high-sensitivity CRP (hsCRP) were associated with the presence of a procoagulant microvasculature. Methods: hsCRP levels were determined using ELISA in serial serum samples (Median: 7; Range: 1 – 7) obtained during the first 3 months following heart transplantation from 120 patients. All patients were evaluated for the presence of a prothrombogenic microvasculature (i.e., lack of microvascular antithrombin, depletion of arteriolar tissue plasminogen activator and presence of microvascular fibrin) within the allografts. Results: Patients ( N = 120) were grouped according to the hsCRP percentile levels. Groups under the 25th percentile ( < 1.1 mg/L), between the 25th and 75th percentiles (1.1 – 6.2 mg/L) and over the 75th percentile ( > 6.2 mg/L) were compared to evaluate differences in the procoagulant status of the microvasculature. A significant association was found between hsCRP levels and levels of vascular antithrombin reactivity ( p < .001), arteriolar tissue plasminogen activator reactivity ( p < .001) and microvascular fibrin deposits ( p < .001), indicating that increased levels of hsCRP were associated with the presence of a procoagulant microvasculature. Each one of these factors was
S137
independently associated with development and severity of Tx-CAD ( p = .01). Conclusions: The present data show that elevated levels of hsCRP are associated with the presence of a procoagulant microvasculature and suggest that this vascular environment promotes development of Tx-CAD and allograft failure. These data emphasize the need to understand the role of CRP in endothelial activation and coagulation in order to further intervene and affect the outcome of heart transplant patients. Showalter Foundation, Indianapolis, IN
P380 POSITIVE REMODELING IN VENOUS BYPASS GRAFTS: NOVEL IMPLICATIONS FOR VEIN GRAFT DISEASE. Amy P. Wong, Zane S. Jackson, Nafiseh Nili, Beiping Qiang, Howard Leong-Poi, Yves LeClerc, Ehud Ranaani, Bradley H. Strauss. University of Toronto. Veins are commonly used as conduits in human coronary artery bypass grafts but often fail within 10 years of grafting due to vein graft atherosclerosis. To date, intimal hyperplasia has been regarded as the principle mechanism responsible for subsequent vein graft disease. The objectives of this study were to determine the extent of lumen remodeling during vein graft repair and the accompanying extracellular matrix and cellular changes in the vein graft wall. Reversed jugular vein-to-common carotid artery interposition grafts were constructed in 65 male New Zealand White rabbits fed a normal diet. Animals were sacrificed at 1, 4 or 12 weeks post surgery. Lumen area, measured by serial intravascular ultrasound, did not change during the first 4 weeks post grafting. However, there was a significant 40% increase in lumen area between 4 and 12 weeks. This positive remodeling temporally corresponded to increased MMP and decreased TIMP activity. This period also corresponded to peak apoptosis rates, maximal macrophage infiltration and marked increases in LDL uptake ( > 3-fold). Positive remodeling is a novel mechanism of vein graft response to the arterial circulation. The accompanying inflammatory and proteolytic response and marked increase in LDL uptake suggest that positive remodeling changes in vein grafts may contribute to susceptibility to accelerated atherosclerosis and premature graft failure.
P381 ROLE OF ALLOGENIC IMMUNE RESPONSE IN THE RECRUITMENT OF HOST-DERIVED SMOOTH MUSCLE CELLS IN TRANSPLANT ARTERIOSCLEROSIS. Piotr Religa, Krzysztof Bojakowski, Maria Bojakowska, Zbigniew Gaciong, Johan Thyberg, Ulf Hedin. Department of Internal Medicine and Hypertension, Medical University of Warsaw, Warsaw, Poland, Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden, Department of Surgical Sciences, Karolinska Institutet, Stockholm, Sweden. Objective: Transplant arterisclerosis involves intimal hyperplasia of smooth muscle cells (SMCs) derived both from the graft and the host. The study explored mechanisms behind accumulation of host-derived SMCs into the neointima. Methods: Intimal hyperplasia was studied after transplantation of infrarenal aorta from female Fischer to male Lewis rats with or without immunosuppression by cyclosporine A (CsA). Infiltration of SMCs and inflammatory cells into the grafts, cell proliferation, and apoptosis were analyzed by immunostaining and laser microdissection followed by real-time PCR for the SRY gene to determine cellular origin. In addition, the effect of alloserum and alloleukocytes on survival of SMCs in vitro was analyzed. Results: Proliferating graft SMCs and infiltrating leukocytes were observed in the intima early after transplantation as indicated by staining
S138
Poster Abstracts / Cardiovascular Pathology 13 (2004) S80–S138
for cyclin D1, proliferating cell nuclear antigen, SMC a-actin, and different leukocyte antigens. Subsequently, proliferating host-derived SMCs were observed together with medial destruction and inflammatory markers. After 8 weeks, the neointima was composed of host-derived SMCs in 80%. Immunosupression with CsA significantly decreased the number of SRY-positive SMCs in the lesions to 37% and restricted
medial destruction. Alloserum significantly increased apoptosis of SMCs in cultures. Conclusions: Development of intimal thickenings during transplant vasculopathy is a dynamic process involving recruitment and proliferation of host-derived SMC and apoptosis of resident graft SMCs triggered by an allogenic immune response.
P379 C-REACTIVE PROTEIN AND MICROVASCULAR PROTHROMBOGENICITY IN HEART TRANSPLANT PATIENTS. Carlos Labarrere, Hector DiCarlo, Miguel Ortiz, Colin Terry, Douglas Pitts, David Hormuth. Methodist Research Institute, Clarian Health Partners, Indianapolis, IN, Clarian Health Transplant Center, Clarian Health Partners, Indianapolis, IN Introduction: Increased serum levels of C-reactive protein (CRP) and activation of endothelium are risk factors for transplant coronary artery disease (Tx-CAD) and graft failure, suggesting that a proinflammatory microenvironment within the allografts plays a significant role in patient’s outcome. Since endothelial activation is associated with a procoagulant status in the microvasculature, we investigated whether elevated levels of high-sensitivity CRP (hsCRP) were associated with the presence of a procoagulant microvasculature. Methods: hsCRP levels were determined using ELISA in serial serum samples (Median: 7; Range: 1 – 7) obtained during the first 3 months following heart transplantation from 120 patients. All patients were evaluated for the presence of a prothrombogenic microvasculature (i.e., lack of microvascular antithrombin, depletion of arteriolar tissue plasminogen activator and presence of microvascular fibrin) within the allografts. Results: Patients ( N = 120) were grouped according to the hsCRP percentile levels. Groups under the 25th percentile ( < 1.1 mg/L), between the 25th and 75th percentiles (1.1 – 6.2 mg/L) and over the 75th percentile ( > 6.2 mg/L) were compared to evaluate differences in the procoagulant status of the microvasculature. A significant association was found between hsCRP levels and levels of vascular antithrombin reactivity ( p < .001), arteriolar tissue plasminogen activator reactivity ( p < .001) and microvascular fibrin deposits ( p < .001), indicating that increased levels of hsCRP were associated with the presence of a procoagulant microvasculature. Each one of these factors was
S137
independently associated with development and severity of Tx-CAD ( p = .01). Conclusions: The present data show that elevated levels of hsCRP are associated with the presence of a procoagulant microvasculature and suggest that this vascular environment promotes development of Tx-CAD and allograft failure. These data emphasize the need to understand the role of CRP in endothelial activation and coagulation in order to further intervene and affect the outcome of heart transplant patients. Showalter Foundation, Indianapolis, IN
P380 POSITIVE REMODELING IN VENOUS BYPASS GRAFTS: NOVEL IMPLICATIONS FOR VEIN GRAFT DISEASE. Amy P. Wong, Zane S. Jackson, Nafiseh Nili, Beiping Qiang, Howard Leong-Poi, Yves LeClerc, Ehud Ranaani, Bradley H. Strauss. University of Toronto. Veins are commonly used as conduits in human coronary artery bypass grafts but often fail within 10 years of grafting due to vein graft atherosclerosis. To date, intimal hyperplasia has been regarded as the principle mechanism responsible for subsequent vein graft disease. The objectives of this study were to determine the extent of lumen remodeling during vein graft repair and the accompanying extracellular matrix and cellular changes in the vein graft wall. Reversed jugular vein-to-common carotid artery interposition grafts were constructed in 65 male New Zealand White rabbits fed a normal diet. Animals were sacrificed at 1, 4 or 12 weeks post surgery. Lumen area, measured by serial intravascular ultrasound, did not change during the first 4 weeks post grafting. However, there was a significant 40% increase in lumen area between 4 and 12 weeks. This positive remodeling temporally corresponded to increased MMP and decreased TIMP activity. This period also corresponded to peak apoptosis rates, maximal macrophage infiltration and marked increases in LDL uptake ( > 3-fold). Positive remodeling is a novel mechanism of vein graft response to the arterial circulation. The accompanying inflammatory and proteolytic response and marked increase in LDL uptake suggest that positive remodeling changes in vein grafts may contribute to susceptibility to accelerated atherosclerosis and premature graft failure.
P381 ROLE OF ALLOGENIC IMMUNE RESPONSE IN THE RECRUITMENT OF HOST-DERIVED SMOOTH MUSCLE CELLS IN TRANSPLANT ARTERIOSCLEROSIS. Piotr Religa, Krzysztof Bojakowski, Maria Bojakowska, Zbigniew Gaciong, Johan Thyberg, Ulf Hedin. Department of Internal Medicine and Hypertension, Medical University of Warsaw, Warsaw, Poland, Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden, Department of Surgical Sciences, Karolinska Institutet, Stockholm, Sweden. Objective: Transplant arterisclerosis involves intimal hyperplasia of smooth muscle cells (SMCs) derived both from the graft and the host. The study explored mechanisms behind accumulation of host-derived SMCs into the neointima. Methods: Intimal hyperplasia was studied after transplantation of infrarenal aorta from female Fischer to male Lewis rats with or without immunosuppression by cyclosporine A (CsA). Infiltration of SMCs and inflammatory cells into the grafts, cell proliferation, and apoptosis were analyzed by immunostaining and laser microdissection followed by real-time PCR for the SRY gene to determine cellular origin. In addition, the effect of alloserum and alloleukocytes on survival of SMCs in vitro was analyzed. Results: Proliferating graft SMCs and infiltrating leukocytes were observed in the intima early after transplantation as indicated by staining
S138
Poster Abstracts / Cardiovascular Pathology 13 (2004) S80–S138
for cyclin D1, proliferating cell nuclear antigen, SMC a-actin, and different leukocyte antigens. Subsequently, proliferating host-derived SMCs were observed together with medial destruction and inflammatory markers. After 8 weeks, the neointima was composed of host-derived SMCs in 80%. Immunosupression with CsA significantly decreased the number of SRY-positive SMCs in the lesions to 37% and restricted
medial destruction. Alloserum significantly increased apoptosis of SMCs in cultures. Conclusions: Development of intimal thickenings during transplant vasculopathy is a dynamic process involving recruitment and proliferation of host-derived SMC and apoptosis of resident graft SMCs triggered by an allogenic immune response.