Gabriel Schnickel - Academia.edu (original) (raw)

Papers by Gabriel Schnickel

Transplantation, 2007

Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading c... more Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading cause of late death among heart transplant recipients. Strategies to control CAV traditionally have focused on lymphocyte functions. We hypothesized that D-4F, an apoA-I mimetic peptide with potent anti-inflammatory/antioxidant properties, will attenuate CAV. We used a previously characterized murine model of CAV. B6.C-H2 hearts were heterotopically transplanted into C57BL/6 mice. Recipient mice were treated with either 20 microg of D-4F or carrier daily. Donor hearts were harvested on day 24 after transplantation. Treatment of recipients with D-4F reduced the severity of intimal lesions (62.5+/-3.4% vs. 31.1+/-8.7%, P<0.009). Treatment also resulted in a decrease in the number of graft-infiltrating CD4 and CD8 lymphocytes and CXCR3+ T-lymphocyte subsets. Heme oxygenase-1 (HO-1) gene transcript in the donor hearts was up-regulated with D-4F treatment, and HO-1 blockade partially reversed the beneficial effects of D-4F. In vitro studies showed that D-4F reduced allogeneic T-lymphocyte proliferation and effector cytokine production. These processes were HO-1 independent. This study suggests that D-4F, a prototypical apoA-I mimetic peptide, is effective in controlling CAV via induction of HO-1 in the graft and a direct effect on T-lymphocyte function. This class of peptides with anti-inflammatory/antioxidant properties provides a novel strategy in the treatment of CAV.

Transplantation, 2004

The role of CD8 lymphocytes, in chronic rejection or cardiac allograft vasculopathy (CAV), is inc... more The role of CD8 lymphocytes, in chronic rejection or cardiac allograft vasculopathy (CAV), is incompletely understood. The purposes of this study were to determine whether CD8 lymphocytes, in the absence of CD4 lymphocytes, are capable of causing the intimal lesions of CAV; and if so, to define the effector mechanism(s) of CD8 lymphocytes. We modified a previously characterized major histocompatibility complex class II mismatched murine model of CAV. Wild-type CD8 lymphocytes were transferred to nude mice followed by heterotopic heart transplantation. Recipient mice were then treated with a CD40 activating antibody, which is known to provide help for CD8 lymphocyte activation, in the absence of CD4 lymphocytes. Donor hearts were harvested on day 40 posttransplantation and analyzed for cellular infiltrates and intimal thickening. In separate experiments, isolated perforin -/-, Fas ligand (FasL) -/-, and interferon (IFN)-gamma -/- CD8 lymphocytes were transferred to nude mice followed by identical experimented protocol. With adaptive transfer of wild-type CD8 lymphocytes, the donor hearts were infiltrated with activated CD8 lymphocytes and displayed significant intimal lesions. Adoptive transfer of perforin -/- and FasL -/- CD8 lymphocytes to nude mice resulted in similar patterns of CD8 lymphocyte infiltration and similar severity of intimal lesions. The donor hearts from IFN-gamma -/- CD8 lymphocyte reconstituted recipients displayed minimal intimal lesions, although CD8 lymphocytes were present in the allografts. Unprimed CD8 lymphocytes in the absence of CD4 lymphocytes can cause intimal lesions of CAV. CD8 lymphocytes production of IFN-gamma, but not the perforin or the FasL-mediated cytotoxicity, is the critical step in the development of intimal lesions.

Transplantation, 2006

Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading c... more Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading cause of late death among heart transplant recipients. We hypothesized that induction of HO-1 by D4-F, an apoA-I mimetic peptide with potent antiinflammatory/ antioxidant properties, attenuated CAV.

Journal of Vascular Surgery, 2003

Purpose: We undertook this study to document the functional natural history of patients undergoin... more Purpose: We undertook this study to document the functional natural history of patients undergoing major amputation in an academic vascular surgery and rehabilitation medicine practice. Methods: A retrospective review was conducted of consecutive patients undergoing major lower extremity amputation and rehabilitation in a university and Department of Veterans Affairs hospital. Main outcome variables included operative mortality, follow-up, survival, median time to incision healing, secondary operative procedures for wound management, and conversion from below-knee amputation (BKA) to above-knee amputation (AKA). For surviving patients, quality of life was determined by degree of ambulation, eg, outdoors, indoors only, or no ambulation; use of a prosthesis; and independence, eg, community housing or nursing facility. Results: From August 1997 through March 2002, 154 patients (130 men; median age, 62 years) underwent 172 major amputations, 78 AKA and 94 BKA, because of either critical limb ischemia (87%) or diabetic neuropathy (13%). Thirty-day operative mortality was 10%. Mean follow-up was 14 months. Healing at 100 and 200 days, as determined with the Kaplan-Meier method, was 55% and 83%, respectively, for BKA, and 76% and 85%, respectively, for AKA. Twenty-three BKA and 16 AKA required additional operative revision, and 18 BKA ultimately were converted to AKA. Survival was 78% at 1 year and 55% at 3 years. Function in surviving patients at 10 and 17 months, respectively, was as follows: 21% and 29% of patients ambulated outdoors, 28% and 25% ambulated indoors only, and 51% and 46% of patients were nonambulatory; 32% and 42% of patients used prosthetic limbs; and 17% and 8% of patients who lived in the community before amputation required care in a nursing facility. Conclusions: We were surprised to find that vascular patients in a contemporary setting who require major lower extremity amputation and rehabilitation often remain independent despite infrequent prosthesis use and outdoor ambulation. Although any hope for postoperative ambulation in this population requires salvaging the knee joint, because of the morbidity incurred in both wound healing and rehabilitation efforts, aggressive effort should be reserved for selected patients at good risk. Ability to predict ambulation after BKA in the vascular population is poor. (J Vasc Surg 2003;38: 7-14.)

The Journal of Thoracic and Cardiovascular Surgery, 2006

Severe primary graft dysfunction occurs in 10% to 20% of lung transplant recipients and is the le... more Severe primary graft dysfunction occurs in 10% to 20% of lung transplant recipients and is the leading cause of early death after lung transplantation. We hypothesized that altering the content of the initial reperfusate and maintaining a low reperfusion pressure after surgical implantation would lead to a low incidence of primary graft dysfunction. We analyzed the records of all patients who underwent lung transplantation at our institution from March 1, 2000, to August 30, 2004. The modified reperfusion technique involved the insertion of a catheter into the main or individual pulmonary artery after implantation. The recipient blood was depleted of leukocytes; supplemented with nitroglycerin; adjusted for pH and calcium level; enriched with aspartate, glutamate, and dextrose; and then administered into the pulmonary arteries of the newly transplanted lung(s) for the first 10 minutes of reperfusion. Severe primary graft dysfunction was defined as a PaO2/inspired oxygen fraction of less than 150 with diffuse infiltrate on the radiograph in absence of other causes. During this interval, 100 patients underwent lung transplantation with the modified reperfusion technique. Forty-two patients underwent single-lung transplantation, of which 5 patients required cardiopulmonary bypass for the procedure. Fifty-eight patients underwent double-lung transplantation; all double-lung transplantation procedures were performed with patients on cardiopulmonary bypass. There were no technical complications associated with the modified reperfusion. The mean PaO2/inspired oxygen fraction at 6 hours in this cohort was 252 +/- 123 mm Hg. The median number of days on the ventilator was 2. More importantly, the incidence of severe primary graft dysfunction in this cohort was 2.0%. The early survival (30-day or in-hospital mortality) of this group of patients was 97%. The technique of modified reperfusion in human lung transplantation is associated with a low incidence of severe primary graft dysfunction and favorable short-term outcomes.

Journal of the American College of Surgeons, 2005

The Journal of Immunology, 2008

Chemokine-chemokine receptor interactions orchestrate mononuclear cells recruitment to the allogr... more Chemokine-chemokine receptor interactions orchestrate mononuclear cells recruitment to the allograft, leading to acute and chronic rejection. Despite biologic redundancy, several experimental studies have demonstrated the importance of CXCR3 and CCR5 in acute rejection of allografts. In these studies, deficiency or blockade of CXCR3 or CCR5 led to prolongation of allograft survival, yet allografts were ultimately lost to acute rejection. Given the above findings and the specificity of mononuclear cells bearing CXCR3 and CCR5, we hypothesized that combined blockade of CXCR3 and CCR5 will lead to indefinite (>100 days) graft survival in a full MHC-mismatched murine cardiac allograft model. The donor hearts in the control group were rejected in 6 +/- 1 days after transplantation. Combined blockade of CXCR3 and CCR5 prolonged allograft survival >15-fold vs the control group; all allografts survived for >100 days. More importantly, the donor hearts did not display any intimal lesions characteristic of chronic rejection. Further analysis of the donor hearts in the CXCR3/CCR5 blockade group demonstrated graft infiltration with CD4(+)CD25(+) T cells expressing the Foxp3 gene. Depletion of CD25(+) cells in the combined CXCR3 and CCR5 blockade group resulted in acute rejection of the allografts in 22 +/- 2 days. Combined CXCR3 and CCR5 blockade also reduced alloantigen-specific T lymphocyte proliferation. Combined CXCR3 and CCR5 blockade is effective in preventing acute and chronic rejection in a robust murine model. This effect is mediated, in part, by CD25(+) regulatory T cell recruitment and control of T lymphocyte proliferation.

The Journal of Heart and Lung Transplantation, 2005

We have previously demonstrated that immunizing MHC inbred miniature swine with synthetic polymor... more We have previously demonstrated that immunizing MHC inbred miniature swine with synthetic polymorphic peptides spanning the ␣1 domain of an allogeneic donor-derived swine leukocyte antigen class I gene leads to the accelerated acute and chronic rejection of class I disparate hearts. Here, we examine whether treating recipients with autologous immature dendritic cells (DCs) pulsed with synthetic class I peptides could down regulate an alloresponse. Methods: T cells were obtained from an animal that had been immunized with the synthetic peptides and used as responders to monocyte-derived immature DCs pulsed with the peptides in a standard peptide proliferation assay. Autologous monocyte-derived immature DCs were pulsed with synthetic donor class I peptides and administered i.v. and s.c. to a recipient of a class I disparate heart on days Ϫ14 and Ϫ7. The recipient then received a 12-day post-operative course of cyclosporine as single agent immunosuppression. Results: T cells stimulated with peptide-pulsed APCs demonstrated a stimulation index of 25.5, while stimulation with peptide-pulsed immature DCs resulted in a stimulation index of 1.9. If the peptidepulsed DCs were matured with LPS and used as stimulators, the stimulation index rose to 5.3. In vivo studies in a single recipient showed that treatment with donor peptide-pulsed autologous DCs did not sensitize the animal to the peptides. Heart allograft survival in the recipient treated with donor peptide-pulsed DCs was not prolonged compared to untreated controls (survival time 35 days vs. survival times of 35-55 days in untreated controls). However, in contrast to recipients primed with allopeptide alone and unprimed controls which developed CAV by 5 days and 28 days, respectively, no intimal proliferation was seen in this heart. Conclusions: These preliminary data suggest that autologous immature DCs pulsed with allopeptides may be able to down-regulate alloresponses in large animals.

The Journal of Heart and Lung Transplantation, 2009

Purpose: The prevention of chronic allograft vasculopathy (CAV) after heart transplantation remai... more Purpose: The prevention of chronic allograft vasculopathy (CAV) after heart transplantation remains a major problem for long-term success. Epsilon protein kinase C (⑀PKC) is a PKC isoform that plays pivotal roles in myocardial infarction and in heart failure. Here we investigate whether PKC epsilon activation is also involved in the development of intimal hyperplasia. Methods and Materials: Rats underwent balloon denudation of the abdominal aorta and received either 3mM ⑀PKC activator (yeRACK), 3mM ⑀PKC inhibitor (⑀V1-2), the carrier control (TAT 47-57 ), or saline by osmotic pump at ϳ3mg/kg/day for 4 weeks (6 rats/group). The treatment began intraoperatively). Aortas were harvested for histologic evaluation, and luminal obliteration and intima/media ratios were analyzed using computer morphometry. Results: Histology of untreated animals revealed marked intimal hyperplasia with moderate luminal obliteration (19.9Ϯ9%). Neointima formation was significantly increased by the ⑀PKC activator (32Ϯ5.5%; pϭ0.017 vs. untreated) and significantly decreased by the ⑀PKC inhibitor (9.1Ϯ4.3%; pϭ0.016 vs. untreated). No difference was observed between the untreated control and the TAT carrier peptide contol groups (pϭ0.43). The intima/media ratio was significantly higher in the ⑀PKC activator group compared to the ⑀PKC inhibitor group (0.67Ϯ0.46 and 0.25Ϯ0.46, respectively; pϭ0.034). Treatment with either of the ePKC regulators was very well tolerated and the animals in the ⑀PKC activator as well as the ⑀PKC inhibitor groups gained weight during the 4 week treatment period (105Ϯ1.9% and 102Ϯ3.4%, respectively; pϭns). No differences in creatinine, BUN, cholesterol, triglycerides, ALT, and AST were observed between the four groups. Conclusions: These data suggest that ⑀PKC activity contributes to the non-immunological development of intimal hyperplasia and that an ⑀PKC-selective inhibitor, such as ⑀V1-2, could augment current therapeutic strategies to suppress the development of vascular stenosis.

The Journal of thoracic and cardiovascular surgery

Inhaled nitric oxide has been shown to reduce pulmonary vascular resistance in patients undergoin... more Inhaled nitric oxide has been shown to reduce pulmonary vascular resistance in patients undergoing cardiothoracic surgery, but it is limited by toxicity, the need for special monitoring, and cost. Inhaled prostacyclin also decreases pulmonary artery pressure, is relatively free of toxicity, requires no specific monitoring, and is less expensive. The objective of this study was to compare nitric oxide and prostacyclin in the treatment of pulmonary hypertension, refractory hypoxemia, and right ventricular dysfunction in thoracic transplant recipients in a prospective, randomized, crossover pilot trial. Heart transplant and lung transplant recipients were randomized to nitric oxide or prostacyclin as initial treatment, followed by a crossover to the other agent after 6 hours. Pulmonary vasodilators were initiated in the operating room for pulmonary hypertension, refractory hypoxemia, or right ventricular dysfunction. Nitric oxide was administered at 20 ppm, and prostacyclin was adminis...

Transplantation, 2007

Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading c... more Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading cause of late death among heart transplant recipients. Strategies to control CAV traditionally have focused on lymphocyte functions. We hypothesized that D-4F, an apoA-I mimetic peptide with potent anti-inflammatory/antioxidant properties, will attenuate CAV. We used a previously characterized murine model of CAV. B6.C-H2 hearts were heterotopically transplanted into C57BL/6 mice. Recipient mice were treated with either 20 microg of D-4F or carrier daily. Donor hearts were harvested on day 24 after transplantation. Treatment of recipients with D-4F reduced the severity of intimal lesions (62.5+/-3.4% vs. 31.1+/-8.7%, P<0.009). Treatment also resulted in a decrease in the number of graft-infiltrating CD4 and CD8 lymphocytes and CXCR3+ T-lymphocyte subsets. Heme oxygenase-1 (HO-1) gene transcript in the donor hearts was up-regulated with D-4F treatment, and HO-1 blockade partially reversed the beneficial effects of D-4F. In vitro studies showed that D-4F reduced allogeneic T-lymphocyte proliferation and effector cytokine production. These processes were HO-1 independent. This study suggests that D-4F, a prototypical apoA-I mimetic peptide, is effective in controlling CAV via induction of HO-1 in the graft and a direct effect on T-lymphocyte function. This class of peptides with anti-inflammatory/antioxidant properties provides a novel strategy in the treatment of CAV.

Transplantation, 2004

The role of CD8 lymphocytes, in chronic rejection or cardiac allograft vasculopathy (CAV), is inc... more The role of CD8 lymphocytes, in chronic rejection or cardiac allograft vasculopathy (CAV), is incompletely understood. The purposes of this study were to determine whether CD8 lymphocytes, in the absence of CD4 lymphocytes, are capable of causing the intimal lesions of CAV; and if so, to define the effector mechanism(s) of CD8 lymphocytes. We modified a previously characterized major histocompatibility complex class II mismatched murine model of CAV. Wild-type CD8 lymphocytes were transferred to nude mice followed by heterotopic heart transplantation. Recipient mice were then treated with a CD40 activating antibody, which is known to provide help for CD8 lymphocyte activation, in the absence of CD4 lymphocytes. Donor hearts were harvested on day 40 posttransplantation and analyzed for cellular infiltrates and intimal thickening. In separate experiments, isolated perforin -/-, Fas ligand (FasL) -/-, and interferon (IFN)-gamma -/- CD8 lymphocytes were transferred to nude mice followed by identical experimented protocol. With adaptive transfer of wild-type CD8 lymphocytes, the donor hearts were infiltrated with activated CD8 lymphocytes and displayed significant intimal lesions. Adoptive transfer of perforin -/- and FasL -/- CD8 lymphocytes to nude mice resulted in similar patterns of CD8 lymphocyte infiltration and similar severity of intimal lesions. The donor hearts from IFN-gamma -/- CD8 lymphocyte reconstituted recipients displayed minimal intimal lesions, although CD8 lymphocytes were present in the allografts. Unprimed CD8 lymphocytes in the absence of CD4 lymphocytes can cause intimal lesions of CAV. CD8 lymphocytes production of IFN-gamma, but not the perforin or the FasL-mediated cytotoxicity, is the critical step in the development of intimal lesions.

Transplantation, 2006

Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading c... more Chronic rejection in transplanted hearts or cardiac allograft vasculopathy (CAV) is the leading cause of late death among heart transplant recipients. We hypothesized that induction of HO-1 by D4-F, an apoA-I mimetic peptide with potent antiinflammatory/ antioxidant properties, attenuated CAV.

Journal of Vascular Surgery, 2003

Purpose: We undertook this study to document the functional natural history of patients undergoin... more Purpose: We undertook this study to document the functional natural history of patients undergoing major amputation in an academic vascular surgery and rehabilitation medicine practice. Methods: A retrospective review was conducted of consecutive patients undergoing major lower extremity amputation and rehabilitation in a university and Department of Veterans Affairs hospital. Main outcome variables included operative mortality, follow-up, survival, median time to incision healing, secondary operative procedures for wound management, and conversion from below-knee amputation (BKA) to above-knee amputation (AKA). For surviving patients, quality of life was determined by degree of ambulation, eg, outdoors, indoors only, or no ambulation; use of a prosthesis; and independence, eg, community housing or nursing facility. Results: From August 1997 through March 2002, 154 patients (130 men; median age, 62 years) underwent 172 major amputations, 78 AKA and 94 BKA, because of either critical limb ischemia (87%) or diabetic neuropathy (13%). Thirty-day operative mortality was 10%. Mean follow-up was 14 months. Healing at 100 and 200 days, as determined with the Kaplan-Meier method, was 55% and 83%, respectively, for BKA, and 76% and 85%, respectively, for AKA. Twenty-three BKA and 16 AKA required additional operative revision, and 18 BKA ultimately were converted to AKA. Survival was 78% at 1 year and 55% at 3 years. Function in surviving patients at 10 and 17 months, respectively, was as follows: 21% and 29% of patients ambulated outdoors, 28% and 25% ambulated indoors only, and 51% and 46% of patients were nonambulatory; 32% and 42% of patients used prosthetic limbs; and 17% and 8% of patients who lived in the community before amputation required care in a nursing facility. Conclusions: We were surprised to find that vascular patients in a contemporary setting who require major lower extremity amputation and rehabilitation often remain independent despite infrequent prosthesis use and outdoor ambulation. Although any hope for postoperative ambulation in this population requires salvaging the knee joint, because of the morbidity incurred in both wound healing and rehabilitation efforts, aggressive effort should be reserved for selected patients at good risk. Ability to predict ambulation after BKA in the vascular population is poor. (J Vasc Surg 2003;38: 7-14.)

The Journal of Thoracic and Cardiovascular Surgery, 2006

Severe primary graft dysfunction occurs in 10% to 20% of lung transplant recipients and is the le... more Severe primary graft dysfunction occurs in 10% to 20% of lung transplant recipients and is the leading cause of early death after lung transplantation. We hypothesized that altering the content of the initial reperfusate and maintaining a low reperfusion pressure after surgical implantation would lead to a low incidence of primary graft dysfunction. We analyzed the records of all patients who underwent lung transplantation at our institution from March 1, 2000, to August 30, 2004. The modified reperfusion technique involved the insertion of a catheter into the main or individual pulmonary artery after implantation. The recipient blood was depleted of leukocytes; supplemented with nitroglycerin; adjusted for pH and calcium level; enriched with aspartate, glutamate, and dextrose; and then administered into the pulmonary arteries of the newly transplanted lung(s) for the first 10 minutes of reperfusion. Severe primary graft dysfunction was defined as a PaO2/inspired oxygen fraction of less than 150 with diffuse infiltrate on the radiograph in absence of other causes. During this interval, 100 patients underwent lung transplantation with the modified reperfusion technique. Forty-two patients underwent single-lung transplantation, of which 5 patients required cardiopulmonary bypass for the procedure. Fifty-eight patients underwent double-lung transplantation; all double-lung transplantation procedures were performed with patients on cardiopulmonary bypass. There were no technical complications associated with the modified reperfusion. The mean PaO2/inspired oxygen fraction at 6 hours in this cohort was 252 +/- 123 mm Hg. The median number of days on the ventilator was 2. More importantly, the incidence of severe primary graft dysfunction in this cohort was 2.0%. The early survival (30-day or in-hospital mortality) of this group of patients was 97%. The technique of modified reperfusion in human lung transplantation is associated with a low incidence of severe primary graft dysfunction and favorable short-term outcomes.

Journal of the American College of Surgeons, 2005

The Journal of Immunology, 2008

Chemokine-chemokine receptor interactions orchestrate mononuclear cells recruitment to the allogr... more Chemokine-chemokine receptor interactions orchestrate mononuclear cells recruitment to the allograft, leading to acute and chronic rejection. Despite biologic redundancy, several experimental studies have demonstrated the importance of CXCR3 and CCR5 in acute rejection of allografts. In these studies, deficiency or blockade of CXCR3 or CCR5 led to prolongation of allograft survival, yet allografts were ultimately lost to acute rejection. Given the above findings and the specificity of mononuclear cells bearing CXCR3 and CCR5, we hypothesized that combined blockade of CXCR3 and CCR5 will lead to indefinite (>100 days) graft survival in a full MHC-mismatched murine cardiac allograft model. The donor hearts in the control group were rejected in 6 +/- 1 days after transplantation. Combined blockade of CXCR3 and CCR5 prolonged allograft survival >15-fold vs the control group; all allografts survived for >100 days. More importantly, the donor hearts did not display any intimal lesions characteristic of chronic rejection. Further analysis of the donor hearts in the CXCR3/CCR5 blockade group demonstrated graft infiltration with CD4(+)CD25(+) T cells expressing the Foxp3 gene. Depletion of CD25(+) cells in the combined CXCR3 and CCR5 blockade group resulted in acute rejection of the allografts in 22 +/- 2 days. Combined CXCR3 and CCR5 blockade also reduced alloantigen-specific T lymphocyte proliferation. Combined CXCR3 and CCR5 blockade is effective in preventing acute and chronic rejection in a robust murine model. This effect is mediated, in part, by CD25(+) regulatory T cell recruitment and control of T lymphocyte proliferation.

The Journal of Heart and Lung Transplantation, 2005

We have previously demonstrated that immunizing MHC inbred miniature swine with synthetic polymor... more We have previously demonstrated that immunizing MHC inbred miniature swine with synthetic polymorphic peptides spanning the ␣1 domain of an allogeneic donor-derived swine leukocyte antigen class I gene leads to the accelerated acute and chronic rejection of class I disparate hearts. Here, we examine whether treating recipients with autologous immature dendritic cells (DCs) pulsed with synthetic class I peptides could down regulate an alloresponse. Methods: T cells were obtained from an animal that had been immunized with the synthetic peptides and used as responders to monocyte-derived immature DCs pulsed with the peptides in a standard peptide proliferation assay. Autologous monocyte-derived immature DCs were pulsed with synthetic donor class I peptides and administered i.v. and s.c. to a recipient of a class I disparate heart on days Ϫ14 and Ϫ7. The recipient then received a 12-day post-operative course of cyclosporine as single agent immunosuppression. Results: T cells stimulated with peptide-pulsed APCs demonstrated a stimulation index of 25.5, while stimulation with peptide-pulsed immature DCs resulted in a stimulation index of 1.9. If the peptidepulsed DCs were matured with LPS and used as stimulators, the stimulation index rose to 5.3. In vivo studies in a single recipient showed that treatment with donor peptide-pulsed autologous DCs did not sensitize the animal to the peptides. Heart allograft survival in the recipient treated with donor peptide-pulsed DCs was not prolonged compared to untreated controls (survival time 35 days vs. survival times of 35-55 days in untreated controls). However, in contrast to recipients primed with allopeptide alone and unprimed controls which developed CAV by 5 days and 28 days, respectively, no intimal proliferation was seen in this heart. Conclusions: These preliminary data suggest that autologous immature DCs pulsed with allopeptides may be able to down-regulate alloresponses in large animals.

The Journal of Heart and Lung Transplantation, 2009

Purpose: The prevention of chronic allograft vasculopathy (CAV) after heart transplantation remai... more Purpose: The prevention of chronic allograft vasculopathy (CAV) after heart transplantation remains a major problem for long-term success. Epsilon protein kinase C (⑀PKC) is a PKC isoform that plays pivotal roles in myocardial infarction and in heart failure. Here we investigate whether PKC epsilon activation is also involved in the development of intimal hyperplasia. Methods and Materials: Rats underwent balloon denudation of the abdominal aorta and received either 3mM ⑀PKC activator (yeRACK), 3mM ⑀PKC inhibitor (⑀V1-2), the carrier control (TAT 47-57 ), or saline by osmotic pump at ϳ3mg/kg/day for 4 weeks (6 rats/group). The treatment began intraoperatively). Aortas were harvested for histologic evaluation, and luminal obliteration and intima/media ratios were analyzed using computer morphometry. Results: Histology of untreated animals revealed marked intimal hyperplasia with moderate luminal obliteration (19.9Ϯ9%). Neointima formation was significantly increased by the ⑀PKC activator (32Ϯ5.5%; pϭ0.017 vs. untreated) and significantly decreased by the ⑀PKC inhibitor (9.1Ϯ4.3%; pϭ0.016 vs. untreated). No difference was observed between the untreated control and the TAT carrier peptide contol groups (pϭ0.43). The intima/media ratio was significantly higher in the ⑀PKC activator group compared to the ⑀PKC inhibitor group (0.67Ϯ0.46 and 0.25Ϯ0.46, respectively; pϭ0.034). Treatment with either of the ePKC regulators was very well tolerated and the animals in the ⑀PKC activator as well as the ⑀PKC inhibitor groups gained weight during the 4 week treatment period (105Ϯ1.9% and 102Ϯ3.4%, respectively; pϭns). No differences in creatinine, BUN, cholesterol, triglycerides, ALT, and AST were observed between the four groups. Conclusions: These data suggest that ⑀PKC activity contributes to the non-immunological development of intimal hyperplasia and that an ⑀PKC-selective inhibitor, such as ⑀V1-2, could augment current therapeutic strategies to suppress the development of vascular stenosis.

The Journal of thoracic and cardiovascular surgery

Inhaled nitric oxide has been shown to reduce pulmonary vascular resistance in patients undergoin... more Inhaled nitric oxide has been shown to reduce pulmonary vascular resistance in patients undergoing cardiothoracic surgery, but it is limited by toxicity, the need for special monitoring, and cost. Inhaled prostacyclin also decreases pulmonary artery pressure, is relatively free of toxicity, requires no specific monitoring, and is less expensive. The objective of this study was to compare nitric oxide and prostacyclin in the treatment of pulmonary hypertension, refractory hypoxemia, and right ventricular dysfunction in thoracic transplant recipients in a prospective, randomized, crossover pilot trial. Heart transplant and lung transplant recipients were randomized to nitric oxide or prostacyclin as initial treatment, followed by a crossover to the other agent after 6 hours. Pulmonary vasodilators were initiated in the operating room for pulmonary hypertension, refractory hypoxemia, or right ventricular dysfunction. Nitric oxide was administered at 20 ppm, and prostacyclin was adminis...