Bistability in orbital trajectories of a chiral self-propelled particle interacting with an external field

In this paper, the dynamics of a self-propelled stochastic particle under the influence of an axisymmetric light field is experimentally studied. The particle under consideration has the main characteristic of carrying a light sensor in an eccentric location. For the chosen experimental conditions, the emerging trajectories are orbital, and, more interestingly, they suggest the existence of bistability. A mathematical model incorporating the key experimental components is introduced. By means of numerical simulations and theoretical analysis, it is found that, in addition to the orbiting behavior, the sensor location could produce trapped or diffusive behaviors. Furthermore, the study reveals that stochastic perturbation and the eccentric location of the sensor are responsible for inducing bistability in the orbital trajectories, supporting experimental observations.

Properties of balanced flows with bottlenecks: Common stylized facts in finance and vibration-driven vehicles

We study experimentally the properties of the flow of mechanical vibration-driven vehicles confined in two chambers connected through a narrow opening. We report that the density of particles around the opening presents critical behavior and scaling properties. By mapping this density to the financial market price, we document that the main stylized facts observed in financial systems have their counterparts in the mechanical system. The experimental model accurately reproduces financial properties such as scaling of the price fluctuation, volatility clustering, and multiscaling.

Clogging Transition of Vibration-Driven Vehicles Passing through Constrictions

We report experimental results on the competitive passage of elongated self-propelled vehicles rushing through a constriction. For the chosen experimental conditions, we observe the emergence of intermittencies similar to those reported previously for active matter passing through narrow doors. Noteworthy, we find that, when the number of individuals crowding in front of the bottleneck increases, there is a transition from an unclogged to a clogged state characterized by a lack of convergence of the mean clog duration as the measuring time increases. It is demonstrated that this transition-which was reported previously only for externally vibrated systems such as colloids or granulars-appears also for self-propelled agents. This suggests that the transition should also occur for the flow through constrictions of living agents (e.g., humans and sheep), an issue that has been elusive so far in experiments due to safety risks.

Dysregulated MicroRNA Expression and Chronic Lung Allograft Rejection in Recipients With Antibodies to Donor HLA

The pathogenesis of chronic rejection, Bronchiolitis Obliterans Syndrome (BOS) following lung transplantation (LT) is poorly understood. We hypothesized that development of antibodies to HLA (DSA) is associated with dysregulation of microRNA (miRNA) that predisposes BOS. Towards this, miRNA profiling of mononuclear cells from 10 stable LT (DSA(-) BOS(-) ), 10 LT with DSA(+) BOS(-) (DSA group) and 10 LT with DSA(+) BOS(+) (BOS group) were performed. Prediction by mirPath indicated that differential miRNAs in DSA(+) BOS(-) compared to stable are significantly up-regulated (relative fold >2, p < 0.05) for TGF-β and B cell receptor signal pathways. A total of seventy-four miRNAs were up-regulated and six miRNAs were down regulated in LT with DSA(+) BOS(+) when compared to stable (relative fold >2, p < 0.05). There was also significant enrichment of cell cycle and gap junction pathways. An inverse correlation between expression of two key miRNAs and their target genes were observed: miR-369-5p and miR-548d were down regulated in DSA(+) LT while their gene targets in TGF-β signal pathways were up-regulated. In addition, miR-628-5p and miR-134 were down regulated and their target genes (B cell development) were up-regulated. Therefore, we conclude that alloimmunity induced changes in miRNAs affecting the TGF-β and B cell receptor signal pathways play important roles in BOS development.

Numerical and experimental study of stochastic resistive switching

In this paper we study the role of noise in the context of resistive switching phenomena by means of experiments and numerical simulations. Experiments are conducted on a manganite sample. We show that the addition of external Gaussian noise to a small amplitude driving signal yields a contrast ratio between low- and high-resistance states, comparable to that obtained by the application of a large amplitude noiseless signal. Furthermore, excellent agreement between numerical simulation and measurement allows us to study resistive switching under varying input conditions and, thus, properly characterize the beneficial role of noise. We believe these results might be of relevance in the area of memory devices where the large scale of electronic integration renders the presence of noise unavoidable.

T regulatory cells play a significant role in modulating MHC class I antibody-induced obliterative airway disease

The molecular mechanisms leading to the development of chronic lung allograft dysfunction following de novo development of antibodies to mismatched donor MHC remain undefined. We demonstrated that intrabronchial administration of antibodies to MHC class I resulted in induction of both innate and adaptive cellular immune responses characterized by a predominance of Th17 specific to lung associated self-antigens Kα1-tubulin and Collagen-V leading to the development of obliterative airway lesions (OAD), correlate of chronic rejection following human lung transplantation. To determine the role of regulatory T cells (Treg) in the pathogenesis of OAD, we administered anti-MHC class I to mice, in which Treg were depleted by conditional ablation of FoxP3+cells. Under this condition, we observed a threefold increase in pulmonary cellular infiltration, luminal occlusion and fibrous deposition when compared anti-MHC class I Ab administered mice maintaining FoxP3. OAD lesions were accompanied with enhanced accumulation of neutrophils along with self-antigen-specific Th17 and humoral responses. However, IL-17-blockade or adoptive transfer of Treg abrogated OAD. We conclude that Treg exerts a suppressive effect on anti-MHC induced IL-8-mediated neutrophil infiltration and innate immune responses that leads to inhibition of Th17 immune responses to lung associated self-antigens which is critical for development of OAD.

Antibodies to K-α 1 tubulin and collagen V are associated with chronic rejection after lung transplantation

Bronchiolitis obliterans syndrome (BOS), the clinical correlate of chronic rejection after lung transplantation, is the leading obstacle to better long-term outcomes. We previously instituted a clinical protocol to screen for donor-specific human leukocyte antigen (HLA) antibodies (DSA) and a preemptive antibody-directed therapy protocol consisting of rituximab and/or intravenous immune globulin. In this study, we retrospectively analyzed serum samples from lung transplant recipients (n = 108) for antibodies to self-antigens (K-α 1 tubulin and collagen V) before and after antibody-directed therapy and correlated the results with the subsequent development of BOS. Seventy-two of the 108 recipients developed antibodies to self-antigens. There was a correlation between the development of antibodies to self-antigens and DSA. Sixteen of the 54 patients who had antibodies to self-antigens and were treated with antibody-directed therapy cleared the antibodies, and they were significantly less likely to develop BOS than those who had persistent antibodies. Furthermore, those who cleared DSA after treatment but had persistent antibodies to self-antigens were significantly more likely to develop BOS than those who cleared these antibodies. We conclude that antibodies to self-antigens are an important risk factor for the development of BOS.

CCR2 regulates monocyte recruitment as well as CD4 T1 allorecognition after lung transplantation

Graft rejection remains a formidable problem contributing to poor outcomes after lung transplantation. Blocking chemokine pathways have yielded promising results in some organ transplant systems. Previous clinical studies have demonstrated upregulation of CCR2 ligands following lung transplantation. Moreover, lung injury is attenuated in CCR2-deficient mice in several inflammatory models. In this study, we examined the role of CCR2 in monocyte recruitment and alloimmune responses in a mouse model of vascularized orthotopic lung transplantation. The CCR2 ligand MCP-1 is upregulated in serum and allografts following lung transplantation. CCR2 is critical for the mobilization of monocytes from the bone marrow into the bloodstream and for the accumulation of CD11c(+) cells within lung allografts. A portion of graft-infiltrating recipient CD11c(+) cells expresses both recipient and donor MHC molecules. Two-photon imaging demonstrates that recipient CD11c(+) cells are associated with recipient T cells within the graft. While recipient CCR2 deficiency does not prevent acute lung rejection and is associated with increased graft infiltration by T cells, it significantly reduces CD4(+) T(h)1 indirect and direct allorecognition. Thus, CCR2 may be a potential target to attenuate alloimmune responses after lung transplantation.

Apyrase treatment prevents ischemia-reperfusion injury in rat lung isografts

OBJECTIVE

Endothelial cells express the ectoenzyme ectonucleoside adenosine triphosphate diphosphohydrolase, an apyrase that inhibits vascular inflammation by catalyzing the hydrolysis of adenosine triphosphate and adenosine diphosphate. However, ectonucleoside adenosine triphosphate diphosphohydrolase expression is rapidly lost following oxidative stress, leading to the potential for adenosine triphosphate and related purigenic nucleotides to exacerbate acute solid organ inflammation and injury. We asked if administration of a soluble recombinant apyrase APT102 attenuates lung graft injury in a cold ischemia reperfusion model of rat syngeneic orthotopic lung transplantation.

METHODS

Male Fisher 344 donor lungs were cold preserved in a low-potassium dextrose solution in the presence or absence of APT102 for 18 hours prior to transplantation into syngeneic male Fisher 344 recipients. Seven minutes after reperfusion, lung transplant recipients received either a bolus of APT102 or vehicle (saline solution). Four hours after reperfusion, APT102- and saline solution-treated groups were evaluated for lung graft function and inflammation.

RESULTS

APT102 significantly reduced lung graft extracellular pools of adenosine triphosphate and adenosine diphosphate, improved oxygenation, and protected against pulmonary edema. Apyrase treatment was associated with attenuated neutrophil graft sequestration and less evidence of tissue inflammation as assessed by myeloperoxidase activity, expression of proinflammatory mediators, and numbers of apoptotic endothelial cells.

CONCLUSIONS

Administration of a soluble recombinant apyrase promotes lung function and limits the tissue damage induced by prolonged cold storage, indicating that extracellular purigenic nucleotides play a key role in promoting ischemia-reperfusion injury following lung transplantation.

Costimulatory blockade-mediated lung allograft acceptance is abrogated by overexpression of Bcl-2 in the recipient

Lung allografts are considered to be more immunogenic than other solid organs. Little is known about the effectiveness of immunosuppressive regimens after lung transplantation. Herein, we describe a novel model of murine vascularized orthotopic lung transplantation we used to study the effects of costimulatory blockade on lung rejection. Transplants were performed in the Balb --> B6 strain combination. Recipients were either not immunosuppressed or received perioperative CD40/CD40L and CD28/B7 costimulatory blockade. Nonimmunosupressed Balb/c --> B6 lung transplants had severe acute rejection 7 days after transplantation and CD8(+) T cells outnumbered CD4(+) T cells within the allografts. Alternatively, B6 recipients that received perioperative costimulatory blockade had minimal inflammation and there were nearly equal numbers of CD8(+) and CD4(+) T cells in these grafts. Approximately one third of graft-infiltrating CD4(+) T cells expressed Foxp3. CD4(+) T cells isolated from these grafts induced apoptosis of alloreactive CD8(+) T cells that were stimulated with donor splenocytes in vitro. In contrast with wild-type B6 recipient mice, we observed severe rejection of Balb/c lungs 7 days after transplantation into Bcl-2 transgenic B6 recipients that had received costimulatory blockade. CD8(+) T cells outnumbered CD4(+) T cells in these immunosuppressed Bcl-2 transgenic recipients and, compared with immunosuppressed wild-type B6 recipients, a lower percentage of graft-infiltrating CD4(+) T cells expressed Foxp3, and a higher percentage of graft-infiltrating CD8(+) T cells expressed intereferon-gamma. Thus, our results show that perioperative blockade of the CD40/CD40L and CD28/B7 costimulatory pathways markedly ameliorates acute rejection of lung allografts in wild type but not Bcl-2 transgenic recipients.

Monocyte differentiation is controlled by MyD88 after mouse orthotopic lung transplantation

In lung grafts, ischemia-reperfusion signals rapidly induce the recruitment and differentiation of host monocytes into macrophages and dendritic cells. The nature of ischemia-reperfusion signals are antigen independent, but have been hypothesized to initiate Toll-like receptor (TLR) and interleukin (IL)-1R-mediated signaling pathways that are thought to potentiate alloimmune responses. We wondered whether MyD88, an adaptor molecule critical for both TLR and IL-1R-mediated inflammatory responses, regulated monocyte differentiation in a mouse model of vascularized orthotopic lung transplantation. Orthotopic left lung transplants were performed in the following syngeneic combinations: CD45.1(+) B6 --> CD45.2(+) MyD88(-/-) and CD45.1(+) B6 --> CD45.2(+) B6. One day later, recipient-derived dendritic cells and macrophage numbers were assessed in the bronchiolar lavage by FACS analysis. Compared with the bronchiolar lavage of wildtype recipients, MyD88(-/-) recipients had lower numbers of dendritic cells in lung graft airways that were of recipient origin. Lower numbers of newly differentiated lung graft dendritic cells was coincident with the appearance of higher numbers of undifferentiated monocytes in the lung airways of MyD88(-/-) recipients as compared with wild-type recipients. Moreover, adoptive transfer experiments demonstrated that MyD88(-/-) monocytes were poorer at differentiating into lung dendritic cells as compared with wild-type monocytes. Taken together, these data show that MyD88 regulates graft-infiltrating monocyte differentiation and suggests a mechanism by which TLR/IL-1R-signaling pathways control adaptive responses in lung allografts through controlling monocyte fate.

Late primary graft dysfunction after lung transplantation and bronchiolitis obliterans syndrome

Primary graft dysfunction (PGD) is a common early complication after lung transplantation. We conducted a retrospective cohort study of 334 recipients to evaluate the impact of PGD graded at 24, 48 and 72 h on the risk of bronchiolitis obliterans syndrome (BOS) development (stage 1) and progression (stages 2 and 3). We constructed multivariable Cox proportional hazards models to determine the risk of BOS attributable to PGD in the context of other potential risk factors including acute rejection, lymphocytic bronchitis and respiratory viral infections. All grades of PGD at all time points were significant risk factors for BOS development and progression independent of acute rejection, lymphocytic bronchitis and respiratory viral infections. Specifically, PGD grade 1 at T24 was associated with a relative risk of BOS stage 1 of 1.93, grade 2 with a relative risk of 2.29 and grade 3 with a relative risk of 3.31. Furthermore, this direct relationship between the severity of PGD and the risk of BOS persisted at all time points. We conclude that all grades of PGD at all time points are independent risk factors for BOS development and progression. Future strategies that might attenuate the severity of PGD may mitigate the risk of BOS.

Expression profiling of human donor lungs to understand primary graft dysfunction after lung transplantation

Lung transplantation is the treatment of choice for end-stage pulmonary diseases. A limited donor supply has resulted in 4,000 patients on the waiting list. Currently, 10-20% of donor organs offered for transplantation are deemed suitable under the selection criteria, of which 15-25% fail due to primary graft dysfunction (PGD). This has spawned efforts to re-examine the current selection criteria as well as search for alternative donor lungs selection criteria. In this study, we attempt to further our understanding of PGD by observing the changes in gene expression across donor lungs that developed PGD versus those that did not. From our analysis, we have obtained differentially expressed transcripts that were involved in signaling, apoptosis and stress-activated pathways. Results also indicate that metallothionein 3 was over expressed in lungs that didn't develop PGD. This is the first such attempt to perform expression profiling of actual human lungs used for transplantation, for the identification of a molecular signature for PGD.

A mouse model of orthotopic vascularized aerated lung transplantation

Outcomes after lung transplantation are markedly inferior to those after other solid organ transplants. A better understanding of cellular and molecular mechanisms contributing to lung graft injury will be critical to improve outcomes. Advances in this field have been hampered by the lack of a mouse model of lung transplantation. Here, we report a mouse model of vascularized aerated single lung transplantation utilizing cuff techniques. We show that syngeneic grafts have normal histological appearance with minimal infiltration of T lymphocytes. Allogeneic grafts show acute cellular rejection with infiltration of T lymphocytes and recipient-type antigen presenting cells. Our data show that we have developed a physiological model of lung transplantation in the mouse, which provides ample opportunity for the study of nonimmune and immune mechanisms that contribute to lung allograft injury.

Sphingosine 1-phosphate inhibits ischemia reperfusion injury following experimental lung transplantation

Ischemia reperfusion (I/R) injury following lung transplantation is exacerbated by the destruction of the endothelial cell barrier leading to pulmonary edema and dysregulated activated lymphocyte migration. Sphingosine 1-phosphate (S1P), a G-coupled protein receptor (GPCR) agonist, has been previously shown to promote endothelial cell tight junction formation and prevent monocyte chemotaxis. We asked if S1P treatment could improve pulmonary function and attenuate I/R injury following syngeneic rat lung transplantation. In comparison to vehicle-treated recipients, S1P administered before reperfusion significantly improved recipient oxygenation following transplantation. Improved graft function was associated with reduced inflammatory signaling pathway activation along with attenuated intragraft levels of MIP-2, TNF-alpha and IL-1beta. Moreover, S1P-treated recipients had significantly less apoptotic endothelial cells, pulmonary edema and graft accumulation of neutrophils than did vehicle-treated recipients. Thus our data show that S1P improves lung tissue homeostasis following reperfusion by enhancing endothelial barrier function and blunting monocytic graft infiltration and inflammation.

CD4+25+ regulatory T cells limit Th1-autoimmunity by inducing IL-10 producing T cells following human lung transplantation

Chronic human lung allograft rejection is manifested by bronchiolitis obliterans syndrome (BOS). BOS has a multifactorial etiology. Previous studies have indicated that both cellular and humoral alloimmunity play a significant role in the pathogenesis of BOS. Recently, autoimmunity has also been demonstrated to contribute to lung allograft rejection in animal models. However, the significance of autoimmunity in BOS remains unknown. In this report, we investigated the role of naturally occurring CD4(+)CD25(+) regulatory T cells (T-regs) in modulating cellular autoimmunity to collagen type V (col-V), a 'sequestered' yet immunogenic self-protein present in the lung tissue, following lung transplantation (LT). We demonstrated that col-V reactive CD4(+) T cells could be detected in the peripheral blood of lung transplant recipients. There was a predominance of IL-10 producing T cells (T(IL-10)) reactive to col-V with significantly lower levels of IFN-gamma and IL-2 producing T cells (Th1 cells). The col-V specific T(IL-10) cells suppressed the proliferation and expansion of col-V specific Th1 cells by IL-10-dependent and contact-independent pathways. The T(IL-10) cells were distinct but their development was dependent on the presence of T-regs. Furthermore, during chronic lung allograft rejection there was a significant decline of T(IL-10) cells with concomitant expansion of col-V-specific IFN-gammaproducing Th1 cells.

Immune mechanisms in the pathogenesis of bronchiolitis obliterans syndrome after lung transplantation

Lung transplantation is recognized as the only viable treatment option in a variety of end-stage pulmonary diseases. However, the long-term survival after lung transplantation is limited by the development of obliterative bronchiolitis, and its clinical correlate bronchiolitis obliterans syndrome (BOS), which is considered to represent chronic lung allograft rejection. Histopathologically, BOS is an inflammatory process that leads to fibrous scarring of the terminal and respiratory bronchioles and subsequent total occlusion of the airways. The specific etiology and pathogenesis of BOS are not well understood. The current premise is that BOS represents a common lesion in which different inflammatory insults such as ischemia-reperfusion, rejection, and infection can lead to a similar histological and clinical outcome. However, the low incidence of BOS in non-transplanted individuals and the observation that early development of BOS is predicted by the frequency and severity of acute rejection episodes indicate that alloimmune-dependent mechanisms play a crucial role in the pathogenesis of BOS. The evidence presented in this review indicates that BOS is the result of humoral and cellular immune responses developed against major histocompatibility complex molecules expressed by airway epithelial cells of the lung allograft. This process is aggravated by alloimmune-independent mechanisms such as ischemia-reperfusion and infection. Currently, treatment of BOS is frequently unsuccessful. Therefore, a better understanding of the immunopathogenesis of BOS is of paramount importance toward improving long-term patient and graft survival after lung transplantation.

Strategies to increase limited donor resources

A number of strategies have been advocated to increase the number of lung donors including: 1) improvement in donor resuscitation; 2) better methods of lung preservation; 3) extension of the lung donor selection criteria; 4) development of a living-related lung donor programme; and 5) utilisation of nonheart beating donors. Other strategies such as the split-lung technique and techniques of lung reduction to accommodate large lungs into a small-size recipient have also been used successfully. In this article, each of these strategies have been reviewed and some recommendations are suggested based on the authors' own experience and that of the literature.

Use of cyclosporine in lung transplantation

Prior to the cyclosporine (CsA) era, there were no long-term survivors from lung transplantation as the immunosuppressive drugs made patients very susceptible to opportunistic infections and anastomotic complications. CsA is a calcineurin inhibitor that binds to cyclophilins and inhibits transcription of interleukin 2 in T cells, thereby preventing proliferation of activated T cells. The initial immunosuppressive regimen at our institution includes CsA, azathioprine, and steroids. Blood levels of CsA (whole blood, TDx assay) are maintained between 250 and 350 ng/mL for 0 to 6 months, 200 to 300 ng/mL for 6 to 12 months, and around 200 ng/mL beyond 12 months following lung transplantation. Nephrotoxicity, hypertension, susceptibility to infections, and malignancy are some of the serious side effects of CsA that limit its therapeutic usefulness. Acute rejection is relatively common with this regimen, and about 60% of all lung transplant recipients are treated for an episode of acute rejection within the first 12 months after lung transplantation. Acute rejection is a probable risk factor for chronic rejection, and obliterative bronchiolitis develops in about 50% of the patients who survive 5 years. Treatment of chronic rejection continues to be a challenge in lung transplantation. CsA and tacrolimus seem to have equivalent results in lung transplantation, although a few patients may benefit from the use of tacrolimus.

Current status of lung transplantation

Two decades have passed since the first successful clinical lung transplant was performed in 1983, and, in the interim, lung transplantation has become the preferred treatment option for a variety of end-stage pulmonary diseases. Remarkable progress has been made in the field through refinement of technique and improved understanding of transplant immunology and microbiology. Unfortunately, donor shortages continue to limit the more widespread application of lung transplantation. In order to address this issue, marginal donors, living lobar and split lung donor techniques, and nonheartbeating donors have been used clinically to increase the number of donor lungs available. Chronic rejection of the lung allograft is currently the major hurdle limiting longterm survival. To date, prevention of known risk factors and treatment strategies have not lessened the devastating toll this process has on lung transplant survival. Better understanding of the cause of chronic rejection is needed in order to develop novel strategies for its treatment. Promotion of immune tolerance is a promising area that could potentially eliminate chronic rejection. The present article discusses recent advances in lung transplantation. It also details the major issues facing the field today. Only through continued clinical and experimental investigation will lung transplantation eventually reach its full potential.

Chronic obstructive pulmonary disease. 10: Bullectomy, lung volume reduction surgery, and transplantation for patients with chronic obstructive pulmonary disease

There are currently three surgical treatments for emphysema: bullectomy, lung transplantation, and lung volume reduction surgery (LVRS). Unfortunately, most emphysema patients are poor candidates for any surgical intervention. A meticulous selection process is favoured in which indications and contraindications are considered and the best solution is devised for each patient. Patients with giant bullae filling half the thoracic volume and compressing relatively normal adjacent parenchyma are offered bullectomy; those with hyperinflation, heterogeneous distribution of destruction, forced expiratory volume in 1 second (FEV(1)) >20%, and a normal carbon dioxide tension (PCO(2)) are offered LVRS; and patients with diffuse disease, lower FEV(1), hypercapnia, and associated pulmonary hypertension are directed towards transplantation. Using these criteria, few patients are serious candidates for surgical procedures. Combinations of LVRS and lung transplantation, either simultaneously or sequentially, are possible but rarely necessary.

Lung transplantation and bronchiolitis obliterans: an evolution in understanding

Major advancements in the field of lung transplantation have occurred over the past thirty-five years. Despite these advancements, limitations in our ability to obtain sufficient numbers of organs and in our comprehension of the problems associated with the procedure persist. The purpose of this article is to review the current understanding of both the surgical procedure and its most unfortunate complication, bronchiolitis obliterans. Even now, after over three decades of experience, this complication remains the most significant cause of morbidity and mortality following lung transplantation. This article is not meant to be an exhaustive review, and certainly there are important topics not covered herein. We have focused the discussion on ongoing studies, which attempt to understand bronchiolitis obliterans at both the clinical as well as the immunopathological level.

Lymphoproliferative disease after lung transplantation: comparison of presentation and outcome of early and late cases

BACKGROUND

Post-transplantation lymphoproliferative disease (PTLD) after lung transplantation has not been fully characterized. In previous studies, the incidence has varied substantially, and most cases have been reported during the first year after transplantation. The purpose of this study was to review our center's experience with PTLD and to analyze the pattern of disease and determinants of outcome.

METHODS

Among 494 adult lung (n = 491) or heart-lung (n = 3) recipients, 30 cases of PTLD were retrospectively identified. The cases were classified by site(s) of involvement, histology and time of onset (early, < or =1 year, and late, >1 year after transplantation). The outcome of each case was ascertained, and risk factors for death were analyzed in a multivariate model.

RESULTS

PTLD was identified in 30 (6.1%) of the recipients during 1,687 patient-years (median 2.8 years) of follow-up. The incidence density was 1.8 cases per 100 patient-years. Fourteen cases were diagnosed during the first year after transplantation, and 16 cases in subsequent years. The incidence density was significantly higher in the first year than in later years (3.3 cases/100 patient-years versus 1.3 cases/100 patient years; p <.008). Presentation in the thorax and involvement of the allograft were significantly more common in the early cases (thorax: 12 of 14, 86%; allograft: 9 of 14, 64%) than in the late cases (thorax: 2 of 16, 12%; allograft: 2 of 16, 12%). There was no difference in survival after the diagnosis of PTLD between the early and late cases, but survival time after diagnosis was significantly longer in cases with, than those without, allograft involvement (median 2.6 years vs 0.2 year, respectively; log rank p = 0.007). The presentation and pattern of organ involvement of PTLD after lung transplantation is related to the time of onset.

CONCLUSIONS

Disease in the thorax and involvement of the allograft are common in the first year after transplantation, but other sites, especially the gastrointestinal tract, predominate later. PTLD that is confined to the allograft appears to have a somewhat better prognosis than disease that involves other sites.

Indirect allorecognition of mismatched donor HLA class II peptides in lung transplant recipients with bronchiolitis obliterans syndrome

A correlation between indirect allorecognition of mismatched donor HLA class I peptides and development of bronchiolitis obliterans syndrome (BOS) after lung transplantation has been previously observed. The aim of this study was to determine whether there was a correlation between indirect allorecognition of mismatched donor HLA class II peptides and development of BOS after lung transplantation. Peripheral blood mononuclear cells from nine BOS+ and nine BOS-lung transplant recipients were cultured with synthetic peptides corresponding to the beta-chain hypervariable region of a mismatched donor HLA-DR molecule. Then, proliferative alloreactivity as well as frequency of alloreactive T cells were determined. In addition, the immunodominant epitopes from the donor HLA-DR molecules were identified in selected patients. T cells from BOS+ patients showed a dose-dependent proliferative alloreactivity against donor HLA-DR peptides that was significantly higher than that observed in BOS- patients (p=0.001). Similarly, the frequency of HLA-DR alloreactive T cells was significantly higher in BOS+ patients than in BOS- patients (p=0.001). This T-cell alloreactivity was directed against a single immunodominant HLA-DR peptide. These results suggest that indirect alloreactivity to donor HLA class II molecules may play a role in the pathogenesis of BOS after lung transplantation.

Current trends in lung transplantation

Lung transplantation provides very good short- and acceptable long-term survival for patients with advanced lung disease. More widespread use of marginal and distant donors can be employed in selected recipients without compromising early or late results. Lack of suitable donor lungs and the development of BOS represent the biggest obstacles to more widespread application and long-term success of lung transplantation. The high rate of acute rejection and subsequent BOS clearly indicates that current immunosuppression strategies are inadequate. Further clinical and laboratory research into the pathogenesis of BOS will perhaps reveal new treatment options.

Outcome of bilateral lung volume reduction in patients with emphysema potentially eligible for lung transplantation

OBJECTIVE

Between January 1993 and May 1998, we performed 200 consecutive bilateral lung volume reduction operations. After initial assessment, 99 of these patients were eligible for lung volume reduction and potentially eligible for immediate or eventual lung transplantation on the basis of age and absence of contraindications. All chose to proceed with lung volume reduction surgery. The outcomes of these 99 patients are reviewed to assess the consequences of proceeding with lung volume reduction surgery on patients potentially eligible for lung transplantation.

METHODS

A retrospective study was performed with the use of a prospectively assembled computer database.

RESULTS

The 61 men and 38 women were 55 +/- 7 years old at evaluation for lung volume reduction. Mean values for first second expired volume, total lung capacity, and residual volume were 24% +/- 8%, 141% +/- 19%, and 294% +/- 54% predicted. There were 4 operative deaths and 17 late deaths. Two-year and 5-year survival after evaluation for lung volume reduction are 92% and 75%. The 32 patients who have been listed for transplantation after lung volume reduction include 15 who have undergone transplantation, 14 who remain on the list, and 3 who have been removed from the list. All 15 transplant recipients survived transplantation and 3 have subsequently died of rejection or late infection. The 12 living recipients have a median post-transplantation follow-up of 1.7 years. The age at transplantation was 58 +/- 5 years with transplantation occurring 3.8 +/- 1.1 years after lung volume reduction. Sixteen of 99 patients underwent lower lobe volume reduction with an increased rate of listing (63%, P =.008) and transplantation (38%, P =.003) compared with patients undergoing upper lobe volume reduction. Patients listed for transplantation were younger, more impaired, and experienced less benefit from lung volume reduction than patients not yet listed for transplantation.

CONCLUSIONS

The preliminary use of lung volume reduction in patients potentially suitable for transplantation does not appear to jeopardize the chances for subsequent successful transplantation.

Lipid-mediated ex vivo gene transfer of viral interleukin 10 in rat lung allotransplantation

BACKGROUND

Recent studies suggest that viral interleukin 10 suppresses alloimmune response in transplantation and that cationic lipids are one of the most promising nonviral vehicles for gene therapy. The aim of this study was to examine the effect of ex vivo lipid-mediated viral IL10 gene transfer into rat lung allografts on subsequent rejection.

METHODS

Male F344 rats (RT1lvl) underwent left lung transplantation with allografts from Brown Norway rats (RT1n). Allografts were transvascularly transfected 15 minutes after harvest with 5 mL of 1:20-diluted (group 1, n = 7) or 1:40-diluted (group 2, n = 6) GL67-pCMVievIL-10 complex. Group 3 (n = 7), serving as the control group, received 1:40-diluted GL67-pCF1-chloramphenicol acetyltransferase complex. All allografts were preserved for 3 hours at 10 degrees C before transplantation. In all groups recipients were killed on postoperative day 5. Transgene expression of viral interleukin 10 was assessed by means of both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Histologic rejection score, allograft gas exchange, exhaled nitric oxide level, and allograft cytokine mRNA expression were also assessed.

RESULTS

Dose-dependent transgene expression of viral interleukin 10 was detected by means of both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Allograft gas exchange (PaO2) in groups 1 (114.06 +/- 61.1 mm Hg) and 2 (108.58 +/- 35.7 mm Hg) was significantly better than that in group 3 (66.4 +/- 8.22 mm Hg; P =.020 and P =.023, respectively). The vascular rejection score in group 1 was significantly lower than that in group 3 (P =.032, Kruskal-Wallis test). Exhaled nitric oxide levels in group 2 (5.150 +/- 6.38 ppb) were significantly lower than those in group 3 (13.517 +/- 10.4 ppb; P =.039). Allograft interleukin 2 mRNA expression levels in group 1 (1.123 +/- 0.23 relative units) were significantly lower than those in group 3 (1.753 +/- 0.71 relative units; P =.038 vs group 3).

CONCLUSIONS

Lipid-mediated ex vivo viral IL10 gene transfer into rat lung allografts improved graft gas exchange, reduced histologic rejection scores, downregulated graft interleukin 2 mRNA expression, and reduced exhaled nitric oxide levels by postoperative day 5. These results suggest a therapeutic potential of graft viral IL10 gene transfer as an effective immunosuppressive strategy against lung allograft rejection.

Recipient intramuscular gene transfer of active transforming growth factor-beta1 attenuates acute lung rejection

BACKGROUND

Gene transfer into the donor graft has been demonstrated to be feasible in reducing ischemia-reperfusion injury and rejection in lung transplantation. This study was undertaken to determine whether intramuscular gene transfer into the recipient can also reduce subsequent lung graft rejection.

METHODS

Brown Norway rats served as donors and F344 rats as recipients. Recipient animals were injected with 10(10) plaque-forming units of adenovirus encoding active transforming growth factor beta1 (group I, n = 6), beta-galactosidase as adenoviral controls (group II, n = 6), or normal saline without adenovirus (group III, n = 6) into both gluteus muscles 2 days before transplantation. Gene expression was confirmed by enzyme-linked immunosorbent assay. Graft function was assessed on postoperative day 5.

RESULTS

Successful gene transfection and expression were confirmed by the presence of active transforming growth factor beta1 protein in muscle and plasma. Oxygenation was significantly improved in group I (group I vs II and III, 353.6 +/- 63.0 mm Hg vs 165.7 +/- 39.9 and 119.1 +/- 41.5 mm Hg; p = 0.02 and 0.004). The muscle transfected with the transforming growth factor beta1 showed granulation tissue with fibroblast accumulation.

CONCLUSIONS

Intramuscular adenovirus-mediated gene transfer of active transforming growth factor beta1 into the recipients attenuates acute lung rejection as manifested by significantly improved oxygenation in transplanted lung allografts. This intramuscular transfection approach as a cytokine therapy is feasible in transplantation and may be useful in reducing rejection as well as reperfusion injury.

ACTIVATION OF HUMAN AIRWAY EPITHELIAL CELLS BY NON-HLA ANTIBODIES DEVELOPED AFTER LUNG TRANSPLANTATION: A POTENTIAL ETIOLOGICAL FACTOR FOR BRONCHIOLITIS OBLITERANS SYNDROME1

BACKGROUND

The main cause of morbidity and mortality after lung transplantation (LT) is bronchiolitis obliterans syndrome (BOS). Anti-HLA antibodies development after LT has been shown to play an important role in BOS pathogenesis. However, the nature of non-HLA antibodies developed after LT and their role in BOS pathogenesis have not been determined.

METHODS

Sera from 16 BOS+ patients and 11 BOS- patients were collected at 12, 24, 36, and 48 months after LT. Anti-HLA class I and class II antibodies were absorbed with pooled human platelets and pooled human lymphoblastoid cell lines, respectively. Then, the presence of non-HLA antibodies against several cell lines from different origin was determined by flow cytometric analysis. Antibody-positive samples were tested for induction of proliferation and growth factor production in two selected airway epithelial cell (AEC) lines.

RESULTS

Five of 16 BOS+ patients (31.2%) and 0 of 11 BOS- patients (0%) developed anti-AEC antibodies after LT (P=0.05). No reactivity against endothelial cells, lymphocytes, monocytes, or granulocytes was detected. Further analysis of two selected sera demonstrated the development of reactivity against a 60-kDa antigen expressed by 60% of AEC lines and only 12% of cell lines from other tissues. Antibody binding to this antigen induced intracellular Ca++ influx, tyrosine phosphorylation, proliferation, and up-regulation of transforming growth factor-beta and heparin-binding epidermal growth factor mRNA transcription in AECs.

CONCLUSIONS

These results indicate that anti-AEC antibodies may play a role in the immunopathogenesis of BOS in the absence of anti-HLA antibodies.

Endobronchial transfection of naked viral interleukin-10 gene in rat lung allotransplantation

BACKGROUND

Recent studies suggest that viral interleukin-10 (vIL-10) suppresses alloimmune response in transplantation. Tissue mRNA expression of inducible nitric oxide synthase (iNOS) and exhaled nitric oxide (NO) levels have been observed to increase in lung allograft rejection. The aims of this study were to examine the feasibility of vIL-10 gene transfer into rat lung allografts and to investigate its effect on subsequent allograft rejection.

METHODS

Male Lewis rats (RT1l) underwent left lung transplantation with allografts from Brown Norway rats (RT1n). The donor rats were endobronchially transfected 2 minutes before harvest with 400 microg (group I, n = 5), 600 microg (group II, n = 5), or 800 microg (group III, n = 5) of naked pCMVievIL-10. Group IV (n = 5) animals, serving as control, received 400 microg of naked pCF1-CAT. All recipients were sacrificed on postoperative day 5. Transgene expression of vIL-10 was assessed by both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Allograft gas exchange, exhaled NO level, histologic rejection score, and mRNA expression of graft cyokines were also assessed.

RESULTS

Transgene expression of lung graft vIL-10 was detected by both reverse transcriptase-polymerase chain reaction and immunohistochemistry. The iNOS mRNA expression in groups I, II, and III was significantly lower than that of group IV (p < 0.05, analysis of variance). Exhaled NO levels in groups I, II, and III were significantly lower than in group IV (p < 0.01, analysis of variance). There was no significant difference between groups with respect to gas exchange, peak airway pressure, or histologic rejection score.

CONCLUSIONS

It appears that endobronchial transfection of naked vIL-10 plasmid in a rat lung allotransplant model is feasible and suppresses lung iNOS mRNA expression and exhaled NO levels. An association between iNOS upregulation and high exhaled NO levels in lung allograft resection was also noted.

Lung transplantation versus lung volume reduction as surgical therapy for emphysema

There are currently two surgical therapies aimed at crippling, end-stage emphysema: lung transplantation and lung volume reduction surgery (LVRS). Unfortunately, most emphysema patients are poor candidates for any surgical intervention. The authors favor a meticulous selection process in which indications and contraindications are considered and the best solution is devised for each patient. Patients with ideal circumstances for LVRS--hyperinflation, heterogeneous distribution of disease, FEV1 of more than 20%, and normal PCO2--are offered LVRS. Patients with diffuse disease, low FEV1, hypercapnia, and associated pulmonary hypertension are directed toward transplantation. LVRS has not been a satisfactory option for patients with a1-antitrypsin deficiency, and we prefer a transplant in most of these patients. With these considerations, we find that few patients are serious candidates for both procedures. Combinations of lung volume reduction and lung transplantation, simultaneously or sequentially, are possible but rarely necessary.

Perioperative complications after living donor lobectomy

OBJECTIVE

Clinical lung transplantation has been limited by availability of suitable cadaveric donor lungs. Living donor lobectomy provides right and left lower lobes from a pair of living donors for each recipient. We reviewed our experience with living donor lobectomy from July 1994 to February 2000.

METHODS

Sixty-two donor lobectomies were performed. The hospital and outpatient records of these 62 donors were retrospectively analyzed to examine the incidence of perioperative complications.

RESULTS

Twenty-four (38.7%) of 62 donors had no perioperative complications and had a median length of hospital stay of 5.0 days. Thirty-eight (61.3%) of 62 donors had postoperative complications. Twelve major complications occurred in 10 patients and included pleural effusions necessitating drainage (n = 4), bronchial stump fistulas (n = 3), bilobectomy (n = 1), hemorrhage necessitating red cell transfusion (n = 1), phrenic nerve injury (n = 1), atrial flutter ultimately necessitating electrophysiologic ablation (n = 1), and bronchial stricture necessitating dilatation (n = 1). These 38 donors had 55 minor complications including persistent air leaks (n = 9), pericarditis (n = 9), pneumonia (n = 8), arrhythmia (n = 7), transient hypotension necessitating fluid resuscitation (n = 4), atelectasis (n = 3), ileus (n = 3), subcutaneous emphysema (n = 3), urinary tract infections (n = 2), loculated pleural effusions (n = 2), transfusion (n = 2), Clostridium difficile colitis (n = 1), puncture of a saline breast implant (n = 1), and severe contact dermatitis secondary to adhesive tape (n = 1). There were no postoperative deaths and only 1 donor required surgical re-exploration.

CONCLUSIONS

Living donor lobectomy can be performed with low mortality and remains an important alternative for potential recipients unable to wait for cadaveric lung allografts. However, morbidity is high and must be considered when potential living donors are being counseled.

Adenovirus-mediated gene transfer of human interleukin 10 ameliorates reperfusion injury of rat lung isografts

OBJECTIVE

The objective of this study was to examine the feasibility of human interleukin 10 gene transfer into rat lung isografts and to investigate the effect of gene transfer on subsequent ischemia-reperfusion injury.

METHODS

Male F344 rats were divided into 4 groups and underwent left lung isotransplantation. Twenty-four hours before harvest, 5 x 10E9 pfu (group I, n = 6) or 1 x 10E10 pfu (group II, n = 7) of AdRSVhIL-10 was intravenously administered to donor rats. In group I-C (n = 6) and group II-C (n = 6), serving as controls, 5 x 10E9 pfu and 1 x 10E10 pfu of AdCMVLacZ were administered, respectively. Grafts were preserved for 18 hours at 4 degrees C before implantation and assessed 24 hours after reperfusion. Transgene expression of human interleukin 10 was assessed by both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Graft inducible nitric oxide synthase, tumor necrosis factor alpha, intercellular adhesion molecule-1, growth-regulated gene product/cytokine-induced neutrophil chemoattractant-1, and monocyte chemotactic protein-1 mRNA expression were assessed by reverse transcriptase-polymerase chain reaction. Isograft gas exchange, exhaled nitric oxide, and myeloperoxidase activity were also analyzed.

RESULTS

Dose-dependent transgene expression was detected by reverse transcriptase-polymerase chain reaction and immunohistochemistry. Arterial PO (2) in groups I (164.72 +/- 85.3 mm Hg) and II (153.19 +/- 113 mm Hg) was significantly higher than in groups I-C (82.37 +/- 19.1 mm Hg) and II-C (77.95 +/- 33.4 mm Hg) (P =.022 and P =.031, respectively). Arterial PCO (2) in group I (33.40 +/- 6.80 mm Hg) was significantly lower than in group I-C (51.23 +/- 11.9 mm Hg) (P =.0096). Myeloperoxidase activity in group II (0.083 +/- 0.031 DeltaOD. min(-1). mg(-1)) was significantly lower than in group II-C (0.117 +/- 0.028 DeltaOD. min(-1). mg(-1)) (P =.044). The inducible nitric oxide synthase mRNA expression in group II (0.627 +/- 0.28) was significantly lower than in group II-C (1.125 +/- 0.63) (P =. 039).

CONCLUSION

Adenovirus-mediated human interleukin 10 gene transfer in vivo into lung isografts ameliorates subsequent ischemia-reperfusion injury. This results in improved graft gas exchange, reduced neutrophil sequestration, and down-regulation of graft inducible nitric oxide synthase mRNA expression.

Lung transplantation is warranted for stable, ventilator-dependent recipients

BACKGROUND

Lung transplantation for patients on ventilators is a controversial use of scarce donor lungs. We have performed 500 lung transplants in 12 years and 21 of these have been in ventilator-dependent patients.

METHODS

A retrospective review of patient records and computerized database was performed. Living patients were contacted to confirm their health and functional status.

RESULTS

Patients included 13 men and 8 women with a mean age of 43 years. Sixteen patients were considered stable awaiting lung transplant, whereas 5 patients were unstable with acute graft failure after prior lung transplantation. Stable patients had been ventilated for a mean of 57 +/- 46 days whereas unstable patients had been supported for 10 +/- 9 days. Half of the patients required cardiopulmonary bypass support during the transplant, and there was no statistical difference in the frequency of CPB in stable and unstable patients (p = 0.61). Three hospital deaths included 0 of 16 of the stable patients and 3 of 5 of the unstable patients (p = 0.01). Long-term actuarial survival was significantly better in stable versus unstable patients (p = 0.02), with 5-year survival 40% for stable patients and 0% for unstable patients.

CONCLUSIONS

Lung transplantation can be successfully conducted in stable patients who have become ventilator dependent after listing for transplantation. Acute retransplantation for early lung dysfunction is high risk and has produced poor long-term results.

Clotrimazole inhibits lung fibroblast proliferation in vitro: implications for use in the prevention and treatment of obliterative bronchiolitis after lung transplantation

BACKGROUND

Immunosuppressive therapy has limited activity against the mesenchymal cell proliferation of obliterative bronchiolitis. Clotrimazole (CLT) has been shown to inhibit proliferation in normal and cancer cell lines. Here we investigate whether CLT inhibits the proliferation of lung mesenchymal cells.

METHODS

Proliferation of human lung fibroblasts (MRC-5) in the presence of CLT was determined by [3H]thymidine incorporation. Messenger ribonucleic acid (mRNA) expression of platelet-derived growth factor (PDGF)-B and transforming growth factor (TGF)-beta after treatment with CLT was measured by reverse transcriptase-polymerase chain reaction.

RESULTS

Treatment of MRC-5 cells with CLT resulted in a significant reduction in proliferation as assessed by DNA incorporation and cell counts compared with dimethylsulfoxide alone. There was no cytotoxic effect associated with CLT treatment. Reverse transcriptase-polymerase chain reaction demonstrated a marked decrease in PDGF-B and TGF-beta mRNA levels in cells treated with CLT compared with those treated with dimethylsulfoxide.

CONCLUSION

CLT inhibits proliferation of human lung fibroblasts. This inhibitory effect is associated with decreased levels of PDGF-B and TGF-beta mRNA expression and may have value in the prevention and treatment of obliterative bronchiolitis.

Increased expression of inflammatory cytokines and adhesion molecules by alveolar macrophages of human lung allograft recipients with acute rejection: decline with resolution of rejection

BACKGROUND

Alveolar macrophages (AM) are the major population in bronchoalveolar lavage (BAL) cells; we assessed their role in human lung allograft recipients by correlating the expression of adhesion molecules and inflammatory cytokines with clinical outcome of allograft.

METHODS

We obtained BAL samples from patients and enriched them for AM in plastic petri dish for 2 hours at 37 degrees C in 5% CO(2). Expression of intercellular adhesion molecule-1 (ICAM-1, CD54), platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31), and CD11c was assessed by flow cytometry using monoclonal antibodies. We assessed cytokine profile using Multi-Probe RNase protection assay.

RESULTS

Alveolar macrophages that express CD11c, CD31 and CD54 were increased in patients with either rejection or infection compared with those without rejection and infection. The difference in the percentage of AM expressing CD11c and CD31 between the rejection group and patients without rejection and infection group was statistically significant (CD11c, p < 0.01; CD31, p < 0.03). Interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist (IL-1Ra), and IL-6 expression was higher in the rejection group than in patients without rejection. Five out of 9 patients in the rejection group expressed high levels of IL-15 and tumor necrosis factor-alpha compared with patients without rejection and infection. The increased number of AM expressing adhesion molecules and elevated expression of cytokines observed during acute rejection declined to basal levels after successful treatment and resolution of rejection. This study demonstrates that lung allograft rejection is associated with increased expression of adhesion molecules and inflammatory cytokines by AM, which could facilitate mononuclear cell adhesion and extravasation contributing to the allograft injury in lung transplant recipients.

Evidence for cytotoxic T lymphocyte response against human lung cancer: reconstitution of antigenic epitope with peptide eluted from lung adenocarcinoma MHC class I

BACKGROUND

Cancer-associated, major histocompatibility complex (MHC)-restricted peptide antigens have been elucidated in human melanomas and ovarian, breast, and renal carcinomas; but relatively little is known about lung cancer antigens.

METHODS

To work toward delineation of lung cancer-associated antigens, we developed tumor infiltrating lymphocytes (TILs), peripheral blood mononuclear cell-derived cytolytic T cell lines (CTL), autologous lung cancer cell lines, and normal lung cell lines from 17 patients undergoing lung cancer resections. The TILs and CTL lines were subsequently evaluated for markers of activation and specific lysis of autologous or allogeneic lung cancer cell lines or both.

RESULTS

Freshly isolated TILs contained a more activated T cell population compared with the patients' peripheral blood T cells as evidenced by an increased expression of HLA-DR, CD25, and CD45RO. TILs isolated from 15 patients lysed allogeneic lung cancer lines. TILs lysed autologous lung cancer but not autologous normal lung or Epstein-Barr virus transformed B cell lines (B-LCL) in 4 of 8 cases tested, suggesting tumor specificity. A CTL line (RHPBL57.1) was generated from peripheral blood mononuclear cells of an HLA-A24(+) patient by stimulation against an established HLA-A24(+) allogeneic lung cancer cell line. RHPBL57.1 lysed the lung cancer cell line in an HLA-A24-restricted manner. Moreover, RHPBL57.1 specifically lysed autologous B-LCL pulsed with peptides, eluted from MHC class I and isolated from the HLA-A24(+) lung cancer cell line.

CONCLUSIONS

TILs isolated from patients with lung cancer are predominantly an activated population of T cells with evidence of tumor and MHC class I-restricted lysis. Furthermore, we provide evidence for a lung cancer-associated, MHC class I-bound peptide antigen(s) that reconstitutes the epitope recognized by a lung cancer specific CD8(+) T cell line derived from a patient with lung cancer.

Selective use of extracorporeal membrane oxygenation is warranted after lung transplantation

OBJECTIVES

Early allograft dysfunction after lung transplantation ranges from subclinical x-ray abnormalities to pulmonary edema, hypoxemia, hypercarbia, and pulmonary hypertension. Management may include extracorporeal circulation to allow recovery of the acute lung injury. We reviewed our experience with extracorporeal membrane oxygenation after lung transplantation to assess the utility of this therapy.

METHODS

A retrospective chart review was performed. Single or bilateral lung transplantation was performed in 444 adults from July 1988 to July 1998. Twelve (2.7%) patients experienced allograft dysfunction severe enough to require extracorporeal membrane oxygenation after failure of conventional therapy, including sedation, paralysis, and inhaled nitric oxide.

RESULTS

Seven of 12 patients requiring extracorporeal membrane oxygenation were discharged from the hospital. Mean and median times to extracorporeal membrane oxygenation support were 1.2 days and 0 days, respectively. Mean length of support was 4.2 days. Four patients died while receiving extracorporeal membrane oxygenation support. One patient was weaned from extracorporeal membrane oxygenation but died during the hospitalization. Two patients required acute retransplantation while receiving extracorporeal membrane oxygenation, and one survived to discharge. Three patients continued to receive extracorporeal membrane oxygenation support for more than 4 days, and all 3 died. All survivors had begun receiving extracorporeal membrane oxygenation support by post-transplantation day 1. Three of 7 patients discharged from the hospital died 12 months, 13 months, and 72 months after transplantation because of bronchiolitis obliterans syndrome (n = 2) or lymphoma (n = 1). Four patients are alive 2, 12, 25, and 54 months after transplantation.

CONCLUSIONS

Extracorporeal membrane oxygenation provides effective therapy for acute post-transplantation lung dysfunction. The frequency and pattern of our extracorporeal membrane oxygenation use reflects bias toward early extracorporeal membrane oxygenation support for isolated graft failure in otherwise intact and uninfected recipients.

Single versus bilateral lung transplantation for idiopathic pulmonary fibrosis: a ten-year institutional experience

OBJECTIVE

Between July 1988 and July 1998, we performed 433 lung transplants. Forty-five patients had idiopathic pulmonary fibrosis, and operations for these patients included 32 single lung transplants and 13 bilateral sequential lung transplants. This study reviews this experience and compares single lung transplantation and bilateral lung transplantation for pulmonary fibrosis.

METHODS

We performed a retrospective review, including inpatient hospital charts, outpatient clinic records, and telephone contact with patients to verify current health status.

RESULTS

Perioperative mortality was 4 (8.9%) patients. One patient underwent redo bilateral lung transplantation for reperfusion injury and graft failure after single lung transplantation. The median hospitalization was 22 days. Actuarial survival at 1 and 5 years was 75.5% and 53.5%, respectively, which was not significantly different from our survival for all recipients (85.5% and 56.4%, respectively). Seventeen (41%) of 41 operative survivors have died. Late causes of death included obliterative bronchiolitis with respiratory failure (9), malignancy (3), and cytomegalovirus pneumonitis (2). Hospital mortality was 3 (9.4%) of 32 after single lung transplantation and 1 (7.7%) of 13 after bilateral lung transplantation. There was no difference between single and bilateral lung transplantation with regard to hospital stay. Four (12.5%) of the 32 patients undergoing single lung transplantation required tracheostomy, whereas 3 (23%) of 13 recipients undergoing bilateral lung transplantation required tracheostomy.

CONCLUSION

Single or bilateral lung transplantations offer viable therapy for patients with pulmonary fibrosis. We demonstrate no benefit of bilateral over single lung transplantation for patients with this diagnosis. Survival after transplantation appears better than that of historic control subjects receiving standard medical care at other institutions.

Toxicity of cationic liposome-DNA complex in lung isografts

BACKGROUND

Cationic lipids have been successfully employed as vectors for gene transfer in lung grafts, yet those lipid vectors have potential toxicity. Furthermore, the optimal concentration of cationic lipids for gene transfection to lung grafts has not been determined. We evaluated liposome concentration/toxicity relationships in an in vivo rat lung transplantation model.

METHODS

Left lungs were harvested and infused via the pulmonary artery with chloramphenicol acetyl-transferase (CAT)-DNA/lipid 67 (cationic lipid)/dioleoylphosphatidylethanolamine complex (4:1:2 in a final concentration ratio). Donor lungs were allocated into six groups according to lipid 67 concentration: group 1, 0 microM (control); group 2, 10 microM; group 3, 50 microM; group 4, 100 microM; group 5, 250 microM; group 6, 500 microM. Forty-eight hours after orthotopic transplantation, the recipient contralateral right main pulmonary artery and bronchus were ligated. The graft was ventilated with 100% oxygen for 5 min. Arterial blood gas analysis (PaO2, PaCO2), peak airway pressure (PAP), and CAT activity of the grafts were measured.

RESULTS

Recipient survival, and PaO2, PAP, and CAT levels correlated with the lipid-DNA complex concentration. The grafts in groups 4-6 were more injured as evidenced by decreased PaO2 and increased PAP levels in comparison to the control group. CAT level was significantly lower in group 2 than in groups 3-6.

CONCLUSIONS

The pulmonary toxicity of cationic lipid is dose-dependent. The balance between lung graft function and transgene expression is optimal at a lipid 67 concentration of 50 microM.

Transforming growth factor-beta1 gene transfer ameliorates acute lung allograft rejection

BACKGROUND

The aim of the current work was to study the feasibility of functional gene transfer using the gene encoding for transforming growth factor-beta1, a known immunosuppressive cytokine, on rat lung allograft function in the setting of acute rejection.

METHODS

The rat left lung transplant technique was used in all experiments, with Brown Norway donor rats and Fischer recipient rats. After harvest, left lungs were transfected ex vivo with either sense or antisense transforming growth factor-beta1 constructs complexed to cationic lipids, then implanted into recipients. On postoperative days 2, 5, and 7, animals were put to death, arterial oxygenation measured, and acute rejection graded histologically.

RESULTS

On postoperative day 2, there were no differences in acute rejection or lung function between animals treated with transforming growth factor-beta1 and control animals. On postoperative day 5, oxygenation was significantly improved in grafts transfected with the transforming growth factor-beta1 sense construct compared with antisense controls (arterial oxygen tension = 411 +/- 198 vs 103 +/- 85 mm Hg, respectively; P =.002). Acute rejection scores from lung allografts were also significantly improved, corresponding to decreases in both vascular and airway rejection (vascular rejection scores: 2.0 +/- 0. 5 vs 2.8 +/- 0.6; P =.04; airway rejection scores: 1.3 +/- 0.7 vs 2. 3 +/- 0.8, respectively; P =.02). The amelioration of acute rejection was temporary and decreased by postoperative day 7.

CONCLUSIONS

The feasibility of using gene transfer techniques to introduce novel functional genes in the setting of lung transplantation is demonstrated. In this model of rat lung allograft rejection, gene transfer of transforming growth factor-beta1 resulted in temporary but significant improvements in lung allograft function and acute rejection pathology.

Development of bronchiolitis obliterans syndrome despite blood chimerism in human lung transplant recipients

Bronchiolitis Obliterans Syndrome (BOS) remains the overwhelming obstacle to the success of lung transplantations (LTx). The presence of donor-specific microchimerism (DSM) and its association with lung allograft function is not well defined. To investigate the relationship between chimerism and BOS, blood was obtained from 21 LTx recipients. Genomic DNA was isolated from patient blood, and PCR-based techniques were used to identify recipient and donor HLA-DR. Fifty percent of the LTx recipients with BOS exhibited DSM at "T1" time post transplant, and 40% at one year follow-up (T2). However, 54% exhibited DSM in the BOS-free group at T1, and 44% at T2. Of the BOS-free, DSM-positive patients at T1, 29% developed BOS by T2. In contrast, 50% of BOS-free DSM-negative patients 50% developed BOS (P > 0.05). Double LTx had a higher prevalence of DSM (73%) and a lower prevalence of BOS (46%) than single LTx (50% and 80% respectively, P > 0.05). One-HLA-DR-antigen-matched LTx recipients show a low prevalence of DSM compared to non-matched (P < 0.05). This study demonstrates that the development of BOS in LTx recipients could also occur in the presence of blood chimerism.