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Margaret D. Allen - One of the best experts on this subject based on the ideXlab platform.
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Cobalt Protoporphyrin Pretreatment Protects Human Embryonic Stem Cell-Derived Cardiomyocytes From Hypoxia/Reoxygenation Injury In Vitro and Increases Graft Size and Vascularization In Vivo
Stem cells translational medicine, 2014Co-Authors: Jun Luo, Matthew S. Weaver, Baohong Cao, James E. Dennis, Benjamin Van Biber, Michael A. Laflamme, Margaret D. AllenAbstract:Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate infarcted myocardium. However, when implanted into acutely infarcted hearts, few cells survive the first week postimplant. To improve early Graft survival, hESC-CMs were pretreated with cobalt protoporphyrin (CoPP), a transcriptional activator of cytoprotective heme oxygenase-1 (HO-1). When hESC-CMs were challenged with an in vitro hypoxia/reoxygenation injury, mimicking cell transplantation into an ischemic site, survival was significantly greater among cells pretreated with CoPP versus phosphate-buffered saline (PBS)-pretreated controls. Compared with PBS-pretreated cells, CoPP-pretreated hESC-CM preparations exhibited higher levels of HO-1 expression, Akt phosphorylation, and vascular endothelial growth factor production, with reduced apoptosis, and a 30% decrease in intracellular reactive oxygen species. For in vivo translation, 1 × 107 hESC-CMs were pretreated ex vivo with CoPP or PBS and then injected intramyocardially into rat hearts immediately following acute infarction (permanent coronary ligation). At 1 week, hESC-CM content, assessed by quantitative polymerase chain reaction for human Alu sequences, was 17-fold higher in hearts receiving CoPP- than PBS-pretreated cells. On histomorphometry, cardiomyocyte Graft Size was 2.6-fold larger in hearts receiving CoPP- than PBS-pretreated cells, occupying up to 12% of the ventricular area. Vascular density of host-perfused human-derived capillaries was significantly greater in Grafts composed of CoPP- than PBS-pretreated cells. Taken together, these experiments demonstrate that ex vivo pretreatment of hESC-CMs with a single dose of CoPP before intramyocardial implantation more than doubled resulting Graft Size and improved early Graft vascularization in acutely infarcted hearts. These findings open the door for delivery of these, or other, stem cells during acute interventional therapy following myocardial infarction or ischemia.
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cobalt protoporphyrin pretreatment protects human embryonic stem cell derived cardiomyocytes from hypoxia reoxygenation injury in vitro and increases Graft Size and vascularization in vivo
Stem Cells Translational Medicine, 2014Co-Authors: Jun Luo, Matthew S. Weaver, Baohong Cao, James E. Dennis, Benjamin Van Biber, Michael A. Laflamme, Margaret D. AllenAbstract:Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate infarcted myocardium. However, when implanted into acutely infarcted hearts, few cells survive the first week postimplant. To improve early Graft survival, hESC-CMs were pretreated with cobalt protoporphyrin (CoPP), a transcriptional activator of cytoprotective heme oxygenase-1 (HO-1). When hESC-CMs were challenged with an in vitro hypoxia/reoxygenation injury, mimicking cell transplantation into an ischemic site, survival was significantly greater among cells pretreated with CoPP versus phosphate-buffered saline (PBS)-pretreated controls. Compared with PBS-pretreated cells, CoPP-pretreated hESC-CM preparations exhibited higher levels of HO-1 expression, Akt phosphorylation, and vascular endothelial growth factor production, with reduced apoptosis, and a 30% decrease in intracellular reactive oxygen species. For in vivo translation, 1 × 107 hESC-CMs were pretreated ex vivo with CoPP or PBS and then injected intramyocardially into rat hearts immediately following acute infarction (permanent coronary ligation). At 1 week, hESC-CM content, assessed by quantitative polymerase chain reaction for human Alu sequences, was 17-fold higher in hearts receiving CoPP- than PBS-pretreated cells. On histomorphometry, cardiomyocyte Graft Size was 2.6-fold larger in hearts receiving CoPP- than PBS-pretreated cells, occupying up to 12% of the ventricular area. Vascular density of host-perfused human-derived capillaries was significantly greater in Grafts composed of CoPP- than PBS-pretreated cells. Taken together, these experiments demonstrate that ex vivo pretreatment of hESC-CMs with a single dose of CoPP before intramyocardial implantation more than doubled resulting Graft Size and improved early Graft vascularization in acutely infarcted hearts. These findings open the door for delivery of these, or other, stem cells during acute interventional therapy following myocardial infarction or ischemia.
Hiroshi Higashiyama - One of the best experts on this subject based on the ideXlab platform.
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Graft Size‐matching in living related partial liver transplantation in relation to tissue oxygenation and metabolic capacity
Transplant International, 1996Co-Authors: Akira Tanaka, Seiji Sato, Yasutsugu Takada, Toshiyuki Kitai, Atsuo Tokuka, Takuya Inomoto, Hisashi Shinohara, Koichi Tanaka, Etsuro Hatano, Hiroshi HigashiyamaAbstract:The influence of Graft Size-matching on tissue oxygenation and metabolic capability was studied in living related partial liver transplantations for 47 pediatric patients. Their age ranged from 4 months to 17 years 3 months, their body weight from 4.0 to 58.0 kg, Graft weight from 191 to 440 g, and Graft weight/recipient body weight ratio from 0.61% to 6.0%. Tissue oxygenation and its heterogeneity were investigated by measuring oxygen saturation of hemoglobin in the liver sinusoid (SO2), coefficient of variation of SO2, and arterial ketone body ratio. The metabolic capacity of the Graft was investigated by measuring bilirubin clearance, recovery of cholesterol esterification, and ketone body production. In infants with a relatively large liver Graft, both intra- and extracellular oxygenation remained low soon after reperfusion but recovered to the control value by the end of the operation. In adolescent recipients of a relatively small Graft, by contrast, synthetic and detoxification capacities were relatively deficient; however, these improved with time. These results indicate that sufficient tissue oxygenation and liver regeneration are essential for successful liver transplantation with relatively large and small Grafts, respectively.
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Graft Size matching in living related partial liver transplantation in relation to tissue oxygenation and metabolic capacity
Transplant International, 1996Co-Authors: Akira Tanaka, Seiji Sato, Yasutsugu Takada, Toshiyuki Kitai, Atsuo Tokuka, Takuya Inomoto, Hisashi Shinohara, Koichi Tanaka, Etsuro Hatano, Hiroshi HigashiyamaAbstract:The influence of Graft Size-matching on tissue oxygenation and metabolic capability was studied in living related partial liver transplantations for 47 pediatric patients. Their age ranged from 4 months to 17 years 3 months, their body weight from 4.0 to 58.0 kg, Graft weight from 191 to 440 g, and Graft weight/recipient body weight ratio from 0.61% to 6.0%. Tissue oxygenation and its heterogeneity were investigated by measuring oxygen saturation of hemoglobin in the liver sinusoid (SO2), coefficient of variation of SO2, and arterial ketone body ratio. The metabolic capacity of the Graft was investigated by measuring bilirubin clearance, recovery of cholesterol esterification, and ketone body production. In infants with a relatively large liver Graft, both intra- and extracellular oxygenation remained low soon after reperfusion but recovered to the control value by the end of the operation. In adolescent recipients of a relatively small Graft, by contrast, synthetic and detoxification capacities were relatively deficient; however, these improved with time. These results indicate that sufficient tissue oxygenation and liver regeneration are essential for successful liver transplantation with relatively large and small Grafts, respectively.
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Graft Size assessment by preoperative computed tomography in living related partial liver transplantation
The British journal of surgery, 1993Co-Authors: Hiroshi Higashiyama, Koichi Tanaka, T. Yamaguchi, K. Mori, Yoshihisa Nakano, Tadashi Yokoyama, Naritaka Yamamoto, Yoshio Yamaoka, Kaoru Kumada, Kazue OzawaAbstract:The Size of segmental liver Grafts assessed by preoperative computed tomography (CT) volumetry was evaluated in relation to surgical outcome in 14 living related partial liver transplantations (LRLTs). The aim was to show that Graft Size can be accurately assessed before operation and to estimate the lower safety limit of Graft Size in assessing subsequent Graft function and survival. The relationship between calculated CT volume and weight of the liver was linear in the recipient (r=0.97) and donor (r=0.98). The mean(s.e.m.) modified liver weight ratio (MLWR; ratio of Graft weight to recipient's expected liver weight based on body-weight) was 0.59(0.07) (range 0.27-1.09)
Koichi Tanaka - One of the best experts on this subject based on the ideXlab platform.
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Impact of Graft Size mismatching on Graft prognosis in liver transplantation from living donors.
Transplantation, 1999Co-Authors: Tetsuya Kiuchi, Mureo Kasahara, Kenji Uryuhara, Yukihiro Inomata, Shinji Uemoto, Katsuhiro Asonuma, Hiroto Egawa, Shiro Fujita, Michihiro Hayashi, Koichi TanakaAbstract:Background. Although living donor liver transplantation for small pediatric patients is increasingly accepted, its expansion to older/larger patients is still in question because of the lack of sufficient information on the impact of Graft Size mismatching. Methods. A total of 276 cases of living donor liver transplantation, excluding ABO-incompatible, auxiliary, or secondary transplants, were reviewed from Graft Size matching. Forty-three cases were highly urgent cases receiving intensive care preoperatively. Cases were categorized into five groups by Graft-to-recipient weight ratio (GRWR): extra-small-for-Size (XS; GRWR
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impact of Graft Size mismatching on Graft prognosis in liver transplantation from living donors
Transplantation, 1999Co-Authors: Tetsuya Kiuchi, Mureo Kasahara, Kenji Uryuhara, Yukihiro Inomata, Shinji Uemoto, Katsuhiro Asonuma, Hiroto Egawa, Shiro Fujita, Michihiro Hayashi, Koichi TanakaAbstract:Background. Although living donor liver transplantation for small pediatric patients is increasingly accepted, its expansion to older/larger patients is still in question because of the lack of sufficient information on the impact of Graft Size mismatching. Methods. A total of 276 cases of living donor liver transplantation, excluding ABO-incompatible, auxiliary, or secondary transplants, were reviewed from Graft Size matching. Forty-three cases were highly urgent cases receiving intensive care preoperatively. Cases were categorized into five groups by Graft-to-recipient weight ratio (GRWR): extra-small-for-Size (XS; GRWR<0.8%, 17 elective and 4 urgent cases), small (S; 0.8
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Direct measurement of Graft and recipient liver fossa Size by computed tomography for avoiding problems due [correction of clue] to large Graft Size in living-related liver transplantation.
Clinical transplantation, 1998Co-Authors: Tetsuro Hirose, Takuya Inomoto, Akira Tanaka, Yukihiro Inomata, Shinji Uemoto, Masaaki Awane, Yoshiharu Shirakata, Takayuki Nada, Fuminori Moriyasu, Koichi TanakaAbstract:We investigated the incidence and manifestation of problems associated with large Graft Size in living-related liver transplantations and assessed the usefulness of determining volume and dimensions of the Graft and recipient's liver fossa by computed tomography to indicate the risk. Five of 150 living related liver transplantations had Grafts that were too large, resulting in difficulty in primary abdominal closure or in sudden worsening of hemodynamics during primary closure. No significant difference existed in recipient age, sex, body weight, selection of the Graft segment, hepatic vein reconstruction, recipient resected liver weight, Graft volumetry value, the ratio of body weight of donor relative to recipient, and the percentage of Graft weight relative to recipient body weight, between the groups with and without these problems. Mean +/- SEM of maximal dimensional ratio, defined as the maximum of the ratios of 3 dimensions of the Graft relative to recipient liver fossa, were 2.36 +/- 0.64 for patients with Grafts that were too large and 1.00 +/- 0.02 for the cases without Size problems. The mean +/- SEM of liver fossa index, defined as the product of 3 dimensions of recipient liver fossa, were (25.03 +/- 7.18) x 10(4) mm3 and (127.54 +/- 5.07) x 10(4) mm3, respectively. These two indices clearly indicated the risk of problems due to large Graft Size, and will help to protect recipients and provide a basis for evaluating Graft Size in reductions.
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Graft Size‐matching in living related partial liver transplantation in relation to tissue oxygenation and metabolic capacity
Transplant International, 1996Co-Authors: Akira Tanaka, Seiji Sato, Yasutsugu Takada, Toshiyuki Kitai, Atsuo Tokuka, Takuya Inomoto, Hisashi Shinohara, Koichi Tanaka, Etsuro Hatano, Hiroshi HigashiyamaAbstract:The influence of Graft Size-matching on tissue oxygenation and metabolic capability was studied in living related partial liver transplantations for 47 pediatric patients. Their age ranged from 4 months to 17 years 3 months, their body weight from 4.0 to 58.0 kg, Graft weight from 191 to 440 g, and Graft weight/recipient body weight ratio from 0.61% to 6.0%. Tissue oxygenation and its heterogeneity were investigated by measuring oxygen saturation of hemoglobin in the liver sinusoid (SO2), coefficient of variation of SO2, and arterial ketone body ratio. The metabolic capacity of the Graft was investigated by measuring bilirubin clearance, recovery of cholesterol esterification, and ketone body production. In infants with a relatively large liver Graft, both intra- and extracellular oxygenation remained low soon after reperfusion but recovered to the control value by the end of the operation. In adolescent recipients of a relatively small Graft, by contrast, synthetic and detoxification capacities were relatively deficient; however, these improved with time. These results indicate that sufficient tissue oxygenation and liver regeneration are essential for successful liver transplantation with relatively large and small Grafts, respectively.
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Graft Size matching in living related partial liver transplantation in relation to tissue oxygenation and metabolic capacity
Transplant International, 1996Co-Authors: Akira Tanaka, Seiji Sato, Yasutsugu Takada, Toshiyuki Kitai, Atsuo Tokuka, Takuya Inomoto, Hisashi Shinohara, Koichi Tanaka, Etsuro Hatano, Hiroshi HigashiyamaAbstract:The influence of Graft Size-matching on tissue oxygenation and metabolic capability was studied in living related partial liver transplantations for 47 pediatric patients. Their age ranged from 4 months to 17 years 3 months, their body weight from 4.0 to 58.0 kg, Graft weight from 191 to 440 g, and Graft weight/recipient body weight ratio from 0.61% to 6.0%. Tissue oxygenation and its heterogeneity were investigated by measuring oxygen saturation of hemoglobin in the liver sinusoid (SO2), coefficient of variation of SO2, and arterial ketone body ratio. The metabolic capacity of the Graft was investigated by measuring bilirubin clearance, recovery of cholesterol esterification, and ketone body production. In infants with a relatively large liver Graft, both intra- and extracellular oxygenation remained low soon after reperfusion but recovered to the control value by the end of the operation. In adolescent recipients of a relatively small Graft, by contrast, synthetic and detoxification capacities were relatively deficient; however, these improved with time. These results indicate that sufficient tissue oxygenation and liver regeneration are essential for successful liver transplantation with relatively large and small Grafts, respectively.
Joseph M. Arcidi - One of the best experts on this subject based on the ideXlab platform.
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Methods for Graft Size selection in aortic valve-sparing operations
The Annals of thoracic surgery, 2000Co-Authors: Donald B. Doty, Joseph M. ArcidiAbstract:Simple and reproducible methods for accurate restoration of aortic root dimensions during aortic valve-sparing operations are described. The methods are based on choice of an appropriate Size vascular Graft based on the measured or desired diameter of the aortic annulus.
Jun Luo - One of the best experts on this subject based on the ideXlab platform.
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Cobalt Protoporphyrin Pretreatment Protects Human Embryonic Stem Cell-Derived Cardiomyocytes From Hypoxia/Reoxygenation Injury In Vitro and Increases Graft Size and Vascularization In Vivo
Stem cells translational medicine, 2014Co-Authors: Jun Luo, Matthew S. Weaver, Baohong Cao, James E. Dennis, Benjamin Van Biber, Michael A. Laflamme, Margaret D. AllenAbstract:Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate infarcted myocardium. However, when implanted into acutely infarcted hearts, few cells survive the first week postimplant. To improve early Graft survival, hESC-CMs were pretreated with cobalt protoporphyrin (CoPP), a transcriptional activator of cytoprotective heme oxygenase-1 (HO-1). When hESC-CMs were challenged with an in vitro hypoxia/reoxygenation injury, mimicking cell transplantation into an ischemic site, survival was significantly greater among cells pretreated with CoPP versus phosphate-buffered saline (PBS)-pretreated controls. Compared with PBS-pretreated cells, CoPP-pretreated hESC-CM preparations exhibited higher levels of HO-1 expression, Akt phosphorylation, and vascular endothelial growth factor production, with reduced apoptosis, and a 30% decrease in intracellular reactive oxygen species. For in vivo translation, 1 × 107 hESC-CMs were pretreated ex vivo with CoPP or PBS and then injected intramyocardially into rat hearts immediately following acute infarction (permanent coronary ligation). At 1 week, hESC-CM content, assessed by quantitative polymerase chain reaction for human Alu sequences, was 17-fold higher in hearts receiving CoPP- than PBS-pretreated cells. On histomorphometry, cardiomyocyte Graft Size was 2.6-fold larger in hearts receiving CoPP- than PBS-pretreated cells, occupying up to 12% of the ventricular area. Vascular density of host-perfused human-derived capillaries was significantly greater in Grafts composed of CoPP- than PBS-pretreated cells. Taken together, these experiments demonstrate that ex vivo pretreatment of hESC-CMs with a single dose of CoPP before intramyocardial implantation more than doubled resulting Graft Size and improved early Graft vascularization in acutely infarcted hearts. These findings open the door for delivery of these, or other, stem cells during acute interventional therapy following myocardial infarction or ischemia.
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cobalt protoporphyrin pretreatment protects human embryonic stem cell derived cardiomyocytes from hypoxia reoxygenation injury in vitro and increases Graft Size and vascularization in vivo
Stem Cells Translational Medicine, 2014Co-Authors: Jun Luo, Matthew S. Weaver, Baohong Cao, James E. Dennis, Benjamin Van Biber, Michael A. Laflamme, Margaret D. AllenAbstract:Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) can regenerate infarcted myocardium. However, when implanted into acutely infarcted hearts, few cells survive the first week postimplant. To improve early Graft survival, hESC-CMs were pretreated with cobalt protoporphyrin (CoPP), a transcriptional activator of cytoprotective heme oxygenase-1 (HO-1). When hESC-CMs were challenged with an in vitro hypoxia/reoxygenation injury, mimicking cell transplantation into an ischemic site, survival was significantly greater among cells pretreated with CoPP versus phosphate-buffered saline (PBS)-pretreated controls. Compared with PBS-pretreated cells, CoPP-pretreated hESC-CM preparations exhibited higher levels of HO-1 expression, Akt phosphorylation, and vascular endothelial growth factor production, with reduced apoptosis, and a 30% decrease in intracellular reactive oxygen species. For in vivo translation, 1 × 107 hESC-CMs were pretreated ex vivo with CoPP or PBS and then injected intramyocardially into rat hearts immediately following acute infarction (permanent coronary ligation). At 1 week, hESC-CM content, assessed by quantitative polymerase chain reaction for human Alu sequences, was 17-fold higher in hearts receiving CoPP- than PBS-pretreated cells. On histomorphometry, cardiomyocyte Graft Size was 2.6-fold larger in hearts receiving CoPP- than PBS-pretreated cells, occupying up to 12% of the ventricular area. Vascular density of host-perfused human-derived capillaries was significantly greater in Grafts composed of CoPP- than PBS-pretreated cells. Taken together, these experiments demonstrate that ex vivo pretreatment of hESC-CMs with a single dose of CoPP before intramyocardial implantation more than doubled resulting Graft Size and improved early Graft vascularization in acutely infarcted hearts. These findings open the door for delivery of these, or other, stem cells during acute interventional therapy following myocardial infarction or ischemia.
