Immunomodulatory effects of mixed hematopoietic chimerism: immune tolerance in canine model of lung transplantation.

Long-term survival after lung transplantation is limited by acute and chronic graft rejection. Induction of immune tolerance by first establishing mixed hematopoietic chimerism (MC) is a promising strategy to improve outcomes. In a preclinical canine model, stable MC was established in recipients after reduced-intensity conditioning and hematopoietic cell transplantation from a DLA-identical donor. Delayed lung transplantation was performed from the stem cell donor without pharmacological immunosuppression. Lung graft survival without loss of function was prolonged in chimeric (n = 5) vs. nonchimeric (n = 7) recipients (p < or = 0.05, Fisher's test). There were histological changes consistent with low-grade rejection in 3/5 of the lung grafts in chimeric recipients at > or =1 year. Chimeric recipients after lung transplantation had a normal immune response to a T-dependent antigen. Compared to normal dogs, there were significant increases of CD4+INFgamma+, CD4+IL-4+ and CD8+ INFgamma+ T-cell subsets in the blood (p < 0.0001 for each of the three T-cell subsets). Markers for regulatory T-cell subsets including foxP3, IL10 and TGFbeta were also increased in CD3+ T cells from the blood and peripheral tissues of chimeric recipients after lung transplantation. Establishing MC is immunomodulatory and observed changes were consistent with activation of both the effector and regulatory immune response.

Heart and lung transplantation in the United States, 1997-2006.

This article highlights trends in heart and lung transplantation between 1997 and 2006, drawing on data from the OPTN and SRTR. The total number of candidates actively awaiting heart transplantation declined by 45% over the last decade, dropping from 2414 patients in 1997 to 1327 patients in 2006. The overall death rates among patients awaiting heart transplantation declined over the same period. The distribution of recipients among the different status groups at the time of heart transplantation changed little between the inception of the new classification system in 1999 and 2005. Deaths in the first year after heart transplantation have steadily decreased. At the end of 2006, 2885 candidates were awaiting a lung transplant, up 10% from the 1997 count. The median time-to-transplant for listed patients decreased by 87% over the decade, dropping from 1053 days in 1997 to 132 days in 2006. Selection for listing and transplantation has shifted toward more urgent patients since the May 2005 implementation of a new lung allocation system based on survival benefit and urgency rather than waiting time. Only 31 heart-lung transplants were performed in 2006, down from a high of 62 in 1997.

Heart and lung transplantation in the United States, 1996-2005.

This article examines the Organ Procurement and Transplantation Network/Scientific Registry of Transplant Recipients data on heart and lung transplantation in the United States from 1996 to 2005. The number of heart transplants performed and the size of the heart waiting list continued to drop, reaching 2126 and 1334, respectively, in 2005. Over the decade, post-transplant graft and patient survival improved, as did the chances for survival while on the heart waiting list. The number of deceased donor lung transplants increased by 78% since 1996, reaching 1407 in 2005 (up 22% from 2004). There were 3170 registrants awaiting lung transplantation at the end of 2005, down 18% from 2004. Death rates for both candidates and recipients have been dropping, as has the time spent waiting for a lung transplant. Other lung topics covered are living donation, recent surgical advances and changes in immunosuppression regimens. Heart-lung transplantation has declined to a small (33 procedures in 2005) but important need in the United States.

Optimizing a canine survival model of orthotopic lung transplantation.

INTRODUCTION: While acute models of orthotopic lung transplantation have been described in dogs, the technical considerations of developing a survival model in this species have not been elaborated. Herein, we describe optimization of a canine survival model of orthotopic lung transplantation. METHODS: Protocols of orthotopic left lung transplantation and single lung ventilation were established in acute experiments (n=9). Four dogs, serving as controls, received autologous, orthotopic lung transplants. Allogeneic transplants were performed in 16 DLA-identical and 16 DLA-mismatched unrelated recipient dogs. Selective right lung ventilation was utilized in all animals. A Malecot tube was left in the pleural space connected to a Heimlich valve for up to 24 hours. To date, animals have been followed up to 24 months by chest radiography, pulmonary function tests, bronchoscopy with lavage, and open biopsies. RESULTS: Long-term survival was achieved in 34/36 animals. Two recipients died intraoperatively secondary to cardiac arrest. All animals were extubated on the operating table, and in all cases the chest tube was removed within 24 hours. Major complications included thrombosis of the pulmonary artery and subcritical stenosis of bronchial anastamosis. One recipient underwent successful treatment of a small bowel intussusception. CONCLUSIONS: We report our experience in developing a survival canine model of orthotopic single lung transplantation. While short-term survival following canine lung transplantation is achievable, we report particular considerations that facilitate animal comfort, early extubation, and lung reexpansion in the immediate postoperative period, further optimizing use of this species for experimental modeling of long-term complications after lung transplantation.

Decreased lung ischemia-reperfusion injury in rats after preoperative administration of cyclosporine and tacrolimus.

OBJECTIVES: Calcineurin inhibitors reduce experimental reperfusion injury in the liver, brain, heart, kidney, and small bowel. These studies were undertaken to determine whether these agents are similarly protective against lung ischemia-reperfusion injury. METHODS: Left lungs of male rats were rendered ischemic for 90 minutes and reperfused for as long as 4 hours. Treated animals received cyclosporine A (INN: ciclosporin; 1 or 5 mg/kg) or tacrolimus (0.2 mg/kg) 6 hours before ischemia, at reperfusion, or 2 hours after reperfusion. Injury was quantitated in terms of tissue polymorphonuclear leukocyte accumulation (myeloperoxidase content), vascular permeability (iodine 125-labeled bovine serum albumin extravasation), and bronchoalveolar lavage leukocyte content. Separate tissue samples were processed for nuclear protein and cytokine messenger RNA. RESULTS: Treatment with cyclosporine (5 mg/kg) or tacrolimus (0.2 mg/kg) 6 hours before reperfusion reduced lung vascular permeability by 54% and 56% relative to control animals (P <.03). The protective effects of cyclosporine and tacrolimus treatment before reperfusion correlated with 42% and 43% reductions in tissue polymorphonuclear leukocyte (myeloperoxidase) content (P <.008) and marked reductions in bronchoalveolar lavage leukocyte accumulation (P <.01). Administration of cyclosporine or tacrolimus at the time of reperfusion or 2 hours into the reperfusion period offered little or no protection. Animals treated before reperfusion also demonstrated marked reductions in nuclear factor kappaB activation and expression of proinflammatory cytokine messenger RNA. CONCLUSION: Cyclosporine and tacrolimus treatment before reperfusion was protective against lung ischemia-reperfusion injury in rats. The mechanism of these protective effects may involve the inhibition of nuclear factor kappaB, a central transcription factor mediating inflammatory injury. The decreased expression of cytokine messenger RNA indicates that both cyclosporine and tacrolimus may exert their protective effects at the pretranscriptional level.

Anatomical considerations in the surgical management of blunt thoracic aortic injury.

PURPOSE: Blunt aortic injury (BAI) involving the thoracic aorta is usually described as occurring at the isthmus. We hypothesized that injuries 1 cm or less from the inferior border of the left subclavian artery (LSCA) are associated with an increased mortality rate compared with injuries that are more distal. METHODS: A retrospective review of patients admitted with the diagnosis of BAI was performed. Injuries were divided into two groups: group I, injuries that were 1 cm or less from the junction of the LSCA and the thoracic aorta; group II, injuries that were more than 1 cm from the LSCA. Primary outcome measures included cross-clamp time, rupture, and death. RESULTS: In a 14-year period, 122 patients were admitted with BAI. The anatomy relative to the LSCA could be determined in 91 patients who underwent operative repair. Forty-two injuries (46%) were classified as group I, and 49 injuries were classified as group II. Group I injuries were characterized by an increased mortality rate (18/42 or 43% in group I vs 11/49 or 22% in group II, P = .04), intraoperative rupture rate (7/42 or 17% in group I vs 1/49 or 2% in group II, P = .003), and cross-clamp time (39.5 +/- 21.9 minutes in group I vs 28.4 +/- 13 minutes in group II, P = .04). Three ruptures occurred while proximal control was being obtained. CONCLUSION: Increased technical difficulty and risk of rupture characterize injuries that occur proximally in the descending thoracic aorta, 1 cm from the LSCA. These injuries may be better managed by instituting bypass before attempting to obtain proximal control and by routinely clamping proximal to the LSCA.

Choice of venous cannulation for bypass during repair of traumatic rupture of the aorta.

BACKGROUND: Choices for venous cannulation for left heart bypass, to assist repair of traumatic rupture of the thoracic aorta, are between the left atrial appendage and pulmonary veins. METHODS: A retrospective chart review was performed of patients who underwent operative repair of ruptured aorta. RESULTS: Over a 15-year period between March 1985 and February 2000, 133 patients were admitted to a level I trauma center with aortic rupture. Of the 50 procedures performed with left heart bypass, the left atrial appendage was cannulated in 19 and pulmonary veins in 31 (four superior, 27 inferior). Complications occurred in 7 of the 19 patients who underwent venous cannulation via the atrial appendage (two ventricular fibrillation, three atrial fibrillation, one pericardial effusion leading to tamponade, and one phrenic nerve injury). Complications occurred in 2 patients who underwent cannulation via pulmonary vein (one atrial fibrillation, one pericardial effusion requiring tapping) (p = 0.02). CONCLUSIONS: Cannulation via the pulmonary veins is associated with a decrease in complication rates compared with cannulation of the atrial appendage.

Cardiopulmonary bypass with deep hypothermic circulatory arrest for a patient with sickle cell anemia: a case report.

A 36-year-old sickle cell anemia patient undergoing a pulmonary thromboendarterectomy required the use of cardiopulmonary bypass incorporating deep hypothermic circulatory arrest. Being aware of reported incidences of sickling crises, a team of the surgeon, anesthesiologist, hematologist, and perfusionist met to devise a plan of treatment. Treatment included preoperative and intraoperative exchange transfusion, optimal blood gas management, and increased blood flows during bypass. The surgical procedure was performed and was successful in reducing pulmonary hypertension, incorporating a team approach and utilizing these techniques. No incidence of adverse sickling events was observed during this procedure.

Endoscopic management of airway complications after lung transplantation.

Airway complications remain a source of significant morbidity after lung transplantation. The current incidence of such complications is 12% to 15%. The associated mortality is 2% to 3%. Extensive necrosis and anastomotic dehiscence have become rare, but granulation tissue accumulation, stenosis, and bronchomalacia persist. The major factors that increase the risk for such complications are those that aggravate anastomotic ischemia. Because blood flow to the donor main-stem bronchus is derived from collateral circulation from the pulmonary arteries, minimizing pulmonary inflammation, optimizing pulmonary blood flow, and limiting exposure to positive pressure ventilation are important considerations. Attention to organ preservation techniques and perioperative management is critically important. Controversy remains regarding the optimal anastomotic technique, but properly done, end-to-end anastomosis is readily reproducible and is associated with a low incidence of complications. Attempts to restore the bronchial circulation surgically are not associated with significant reductions in airway complications. Similarly, the routine use of vascularized soft tissue reinforcement no longer seems justified. Most complications can be managed readily with a combination of endoscopic techniques, including débridement (with or without laser or cryotherapy), dilation, and stent placement. Resective procedures rarely are indicated, and retransplantation should be reserved for exceptional cases.

Role of RANTES in experimental cardiac allograft rejection.

The host response to alloantigen results in upregulation of Class II MHC antigens and associated cytokine production (especially IL-2 and interferon-gamma (IFN-gamma)) as well as lymphocytic infiltration and cellular activation which leads to graft damage/destruction. RANTES (Regulated upon Activation, Normal T-cell Expressed and presumably Secreted) is a member of the beta subfamily (CC) of chemokines and has been shown to function as a lymphocyte chemoattractant. We now describe the requirement for RANTES in cardiac heterotopic allograft (brown Norway into Lewis rats) rejection in rats. By Northern blot analysis, mRNA could be detected in allografts at 6 and 8 days post-transplantation but not in isogenic (Lewis) grafts. RANTES protein could be demonstrated by Western blot analysis in homogenates from allografts at day 8 but not at day 0 and could not be identified in isogenic cardiac transplants. By immunostaining, RANTES protein was present in mononuclear cells of allografts at day 6 but was absent in the isogenic transplants. When rats were treated with anti-RANTES serum, there was a significant delay in rejection time (cessation of beating) of the allografts. These data demonstrate that expression of RANTES in rat cardiac allografts is linked to the rejection phenomenon.

Regulatory role of Th-2 cytokines, IL-10 and IL-4, in cardiac allograft rejection.

The host response to alloantigen results in T- and B-cell activation, upregulation of Class II MHC antigens, and cytokine production by Th-1 cells, resulting in generation of IL-2 and IFN gamma. Th-2 cell responses produce IL-4 and IL-10 which may shift the immune response from the Th-1 pathway to Th-2 responses, favoring Ig production. This could imply that Th-2-related cytokines protect allografts. In the following studies, employing cardiac heterotopic allografts in rats (Brown Norway into Lewis), we investigated regulatory roles of Th-2-related cytokines IL-4 and IL-10. Two strategies were used in animals receiving allografts: antibody-induced blocking of endogenous IL-4 or IL-10 and exogenous administration of either interleukin. Antibody to IL-4 failed to alter the rejection time, whereas anti-IL-10 greatly accelerated the rejection process. Northern blot analysis of RNA from allografted hearts revealed mRNA for both IL-4 and IL-10, while immunostaining showed strong staining for IL-10 and very weak staining for IL-4. Exogenous administration of either IL-4 or 10 caused prolongation of allograft rejection times. These findings suggest that in rat cardiac allografts intrinsic IL-10 functions to attenuate the rejection process.

Anti-inflammatory effects of mutant forms of secretory leukocyte protease inhibitor.

The secretory leukocyte protease inhibitor (SLPI) is found in a variety of secreted fluids in mammals and is a known inhibitor of serine proteases. Wild-type (WT) SLPI has recently been shown to block nuclear factor kappaB (NF-kappaB) activation in rat lungs and to interfere with the ensuing inflammatory response and recruitment of neutrophils after an intrapulmonary deposition of IgG immune complexes. In this study, WT SLPI and SLPI mutants with various degrees of protease-inhibitory capacity (for trypsin, chymotrypsin, and elastase) were evaluated for their ability to suppress the lung-vascular leak, neutrophil accumulation, and NF-kappaB activation in the lung inflammatory model. The SLPI mutant with Gly(72) (replacing Leu(72) ) lost its ability to block in vivo activation of NF-kappaB, as well as its ability to suppress the lung vascular leak and neutrophil recruitment. The Phe(72) and Gly(20) mutants were as effective as the WT SLPI in suppressing NF-kappaB activation and neutrophil recruitment. The Lys(72) mutant had the most suppressive effects of the lung vascular leak and for neutrophil recruitment into the lung. The in vivo suppressive effects of SLPI mutants on lung vascular permeability, neutrophil recruitment, and NF-kappaB activation appear to be most closely related to their trypsin-inhibiting activity. These data suggest that the suppressive effects of SLPI on the intrapulmonary activation of NF-kappaB and neutrophil recruitment into the lung may be linked to their antiprotease activity, directed, perhaps, at the intracellular proteases.

Role of CC chemokines (macrophage inflammatory protein-1 beta, monocyte chemoattractant protein-1, RANTES) in acute lung injury in rats.

The role of the CC chemokines, macrophage inflammatory protein-1 beta (MIP-1 beta), monocyte chemotactic peptide-1 (MCP-1), and RANTES, in acute lung inflammatory injury induced by intrapulmonary deposition of IgG immune complexes injury in rats was determined. Rat MIP-1 beta, MCP-1, and RANTES were cloned, the proteins were expressed, and neutralizing Abs were developed. mRNA and protein expression for MIP-1 beta and MCP-1 were up-regulated during the inflammatory response, while mRNA and protein expression for RANTES were constitutive and unchanged during the inflammatory response. Treatment of rats with anti-MIP-1 beta Ab significantly decreased vascular permeability by 37% (p = 0.012), reduced neutrophil recruitment into lung by 65% (p = 0.047), and suppressed levels of TNF-alpha in bronchoalveolar lavage fluids by 61% (p = 0.008). Treatment of rats with anti-rat MCP-1 or anti-rat RANTES had no effect on the development of lung injury. In animals pretreated intratracheally with blocking Abs to MCP-1, RANTES, or MIP-1 beta, significant reductions in the bronchoalveolar lavage content of these chemokines occurred, suggesting that these Abs had reached their targets. Conversely, exogenously MIP-1 beta, but not RANTES or MCP-1, caused enhancement of the lung vascular leak. These data indicate that MIP-1 beta, but not MCP-1 or RANTES, plays an important role in intrapulmonary recruitment of neutrophils and development of lung injury in the model employed. The findings suggest that in chemokine-dependent inflammatory responses in lung CC chemokines do not necessarily demonstrate redundant function.

The CXC chemokine, monokine induced by interferon-gamma, inhibits non-small cell lung carcinoma tumor growth and metastasis.

Angiogenesis is an absolute requirement for tumor growth beyond 2 mm3 in size. The balance in expression between opposing angiogenic and angiostatic factors controls the angiogenic process. The CXC chemokines are a group of chemotactic cytokines that possess disparate activity in the regulation of angiogenesis. Non-small cell lung carcinoma (NSCLC) has an imbalance in expression of ELR+ (angiogenic) compared with ELR- (angiostatic) CXC chemokines that favors angiogenesis and progressive tumor growth. We found that the level of the ELR- CXC chemokine MIG (monokine induced by interferon gamma) in human specimens of NSCLC was not significantly different from that found in normal lung tissue. These results suggested that the increased expression of ELR+ CXC chemokines found in these tumor samples is not counterregulated by a concomitant increase in the expression of the angiostatic ELR-CXC chemokine MIG. This would result in an even more profound imbalance in the expression of regulatory factors of angiogenesis that would favor neovascularization. We hypothesized that MIG might be an endogenous inhibitor of NSCLC tumor growth in vivo and that reconstituion of MIG in the tumor microenvironment would result in the inhibition of tumor growth and metastasis. In support of this hypothesis, we demonstrate here that overexpression of the ELR-CXC chemokine MIG, by three different strategies including gene transfer, results in the inhibition of NSCLC tumor growth and metastasis via a decrease in tumor-derived vessel density. These findings support the importance of the ELR- CXC chemokine MIG in inhibiting NSCLC tumor growth by attenuation of tumor-derived angiogenesis. Furthermore, these findings demonstrate the potential of gene therapy as an alternative means to deliver and overexpress a potent angiostatic CXC chemokine.

Endothelial targeting and enhanced antiinflammatory effects of complement inhibitors possessing sialyl Lewisx moieties.

The complement inhibitor soluble complement receptor type 1 (sCR1) and a truncated form of sCR1, sCR1[desLHR-A], have been generated with expression of the selectin-reactive oligosaccharide moiety, sialyl Lewisx (sLex), as N-linked oligosaccharide adducts. These modified proteins, sCR1sLex and sCR1[desLHR-A]sLex, were assessed in the L-selectin- and P-selectin-dependent rat model of lung injury following systemic activation of complement by cobra venom factor and in the L-selectin-, P-selectin-, and E-selectin-dependent model of lung injury following intrapulmonary deposition of IgG immune complexes. In the cobra venom factor model, sCR1sLex and sCR1[desLHR-A]sLex caused substantially greater reductions in neutrophil accumulation and in albumin extravasation in lung when compared with the non-sLex-decorated forms. In this model, increased lung vascular binding of sCR1sLex and sCR1[desLHR-A]sLex occurred in a P-selectin-dependent manner, in contrast to the absence of any increased binding of sCR1 or sCR1[desLHR-A]. In the IgG immune complex model, sCR1[desLHR-A]sLex possessed greater protective effects relative to sCR1[desLHR-A], based on albumin extravasation and neutrophil accumulation. Enhanced protective effects correlated with greater lung vascular binding of sCR1[desLHR-A]sLex as compared with the non-sLex-decorated form. In TNF-alpha-activated HUVEC, substantial in vitro binding occurred with sCR1[desLHR-A]sLex (but not with sCR1[desLHR-A]). This endothelial cell binding was blocked by anti-E-selectin but not by anti-P-selectin. These data suggest that sLex-decorated complement inhibitors have enhanced antiinflammatory effects and appear to have enhanced ability to localize to the activated vascular endothelium.

Cytokine and adhesion molecule requirements for neutrophil recruitment during glycogen-induced peritonitis.

OBJECTIVE: Requirements for cytokines and adhesion molecules for peritoneal neutrophil recruitment during glycogen-induced peritonitis in rats were systematically defined. SUBJECTS: Male Long Evans rats (275-300 g). METHODS: Four hours after intraperitoneal injection of 25 mg oyster glycogen, neutrophilic exudates were harvested. Effects of blocking reagents (injected intravenously) to rat E-, L- and P-selectins, beta1 (VLA-4) and beta2 integrins (LFA-1 and Mac-1), ICAM-1, and the cytokines TNFalpha, IL- and IL-8 were assessed. RESULTS: Administration of synthetic sialyl Lewis(x) oligosaccharide reduced neutrophil recruitment to the peritoneum by 26%. Antibody to E-selectin reduced neutrophil accumulation by 71%, while anti-L-selectin reduced neutrophil accumulation by 59%, and anti-P-selectin was without an effect. Similar patterns of inhibition were found when selectin-Ig chimeras were employed. Antibodies to LFA-1 (CD11a), Mac-1 (CD11b) or CD18 reduced neutrophil accumulation by 62 percent, 59 percent and 86%, respectively, while anti-VLA-4 was without effect. Anti-ICAM-1 reduced cell influx by 65%. IL-1 receptor antagonist and antibodies to IL-1 and human IL-8 reduced neutrophil accumulation by 43alpha, 40% and 62 percent, respectively. Unexpectedly, blockade of TNFalpha had no effect. CONCLUSIONS: These studies identify requirements for selectins, beta2 integrins, IL-1 and a rat chemokine(s) similar to human IL-8 for neutrophil recruitment during glycogen-induced peritonitis. The lack of participation of VLA-4, P-selectin and TNFalpha suggests organ-specific cytokine and adhesion molecule requirements for neutrophil recruitment.

Cytokine and adhesion molecule requirements for lung injury induced by anti-glomerular basement membrane antibody.

Acute hemorrhagic lung injury occurs in humans with anti-GBM antibody (Goodpasture's syndrome), however, the mechanism of this injury is still largely unknown. To date, treatment has been confined to steroids and plasmaphoresis. Infusion of anti-GBM antibody into rats caused lung injury with intra-alveolar hemorrhage and intrapulmonary accumulation of neutrophils. Lung injury was dependent on the presence of neutrophils and complement and required both TNF alpha and IL-1. Experiments employing blocking antibodies to adhesion molecules demonstrated requirements for the beta 1 integrin VLA-4, beta 2 integrins LFA-1 and Mac-1, and L-selection. The endothelial cell adhesion molecules, E-selectin and ICAM-1, were also required for the full development of lung injury. Inhibition of TNF alpha or IL-1 or adhesion molecules reduced both lung injury and tissue neutrophil accumulation. Thus, this study underscores cytokine and adhesion molecule requirements for neutrophil mediated injury in lung and kidney caused by anti-GBM, suggesting potential targets for the treatment of Goodpasture's syndrome in humans.