The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymat... more The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymatic properties. Catalytically, it functions as an exopeptidase, modulating biological activity of key chemokines and peptides. Here we investigated the effect of organ-specific inhibition of DPP IV catalytic activity on ischemia/reperfusion injury after extended ischemia in the mouse model of orthotopic single lung transplantation. C57BL/6 mice were syngeneically, transplanted, grafts were perfused and stored in Perfadex with (treated) or without (control) a DPP IV enzymatic activity inhibitor (AB192). Transplantation was performed after 18 h cold ischemia time; following 2-h reperfusion, grafts were analyzed for oxygenation, thiobarbituric acid-reactive substances, histomorphology, and immunohistochemistry was performed for leukocyte Ag 6, myeloperoxidase, hemoxygenase 1, vasoactive intestinal protein (VIP), and real-time PCR for VIP. Treatment with the DPP IV inhibitor AB192 resulted in significant improvement of gas exchange, less lipid oxidation, preservation of parenchymal ultrastructure, reduced neutrophil infiltration, reduced myeloperoxidase expression, increased hemoxygenase 1 expression, pronounced expression of VIP in alveolar macrophages and increased mRNA expression of VIP. Inhibition of intragraft DPP IV catalytic activity with AB192 strikingly ameliorates ischemia/reperfusion injury after extended ischemia. Furthermore, preservation of endogenous intragraft VIP levels correlate with maintaining lung function and structural integrity.
European Journal of Cardio-Thoracic Surgery, Aug 1, 2003
Objective: To date numerous attempts have been undertaken to conquer the challenging problem of r... more Objective: To date numerous attempts have been undertaken to conquer the challenging problem of reconstructing long segmental tracheal defects, as yet without lasting success. Recently, employing concepts of tissue engineering in animals, cartilage-like constructs were transplanted in vivo. However, both the feasibility of fabricating tracheal replacements and the use of human tracheal chondrocytes (HTC) for tissue engineering are still under investigation. In this study, we optimized isolation and cultivation techniques for human tracheal cartilage, assessing the feasibility of seeding these cells onto a novel, three-dimensional (3-D) polyester-urethane polymer (DegraPol w). Methods: Human tracheal cartilage was harvested from the trachea of lung donors, digested in 0.3% collagenase II, and the condrocytes serially passaged every 7-9 days. Cells were also cultivated over agar plate during the total 6-8 weeks expansion phase. Thereafter, chondrocytes were seeded onto DegraPol w (pore sizes 150-200 mm) with a seeding density of 2:4 £ 10 7 =ml, and chondrocyte-polymer constructs maintained during in vitro static culture. Results: HTC displayed stable proliferation kinetics in monolayer culture with positive expression of collagen type II. Following polymer seeding, both cellular proliferation and extracellular matrix (ECM) production, as measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and glycosaminoglycan assays, continued over extended culture. Active growth of HTC on DegraPol w was further demonstrated by Alcian blue staining, with the histomorphological appearance of the construct resembling that of native cartilage. Scanning electron microscopy showed chondrocyte growth and ECM synthesis both on the surface and inside the porous scaffold, with a dense cell layer on the surface of the scaffold and a lower cell distribution in the scaffold's interior. Conclusions: The harvested chondrocytes from human trachea cartilage expand well in vitro and possess the ability to form new cartilage-like tissue when seeded onto DegraPol w matrix. However, improved culture conditions are needed to permit cellular growth throughout cell-polymer constructs.
The Journal of Thoracic and Cardiovascular Surgery, Feb 1, 2009
Progress in studying acute and chronic pulmonary allograft rejection has been hampered by the lac... more Progress in studying acute and chronic pulmonary allograft rejection has been hampered by the lack of feasible experimental animal transplantation models. Contemporary approaches are limited by anatomic applicability (heterotopic tracheal implantation) and lack of genetic variability (rat model). To utilize the breadth of available genetic modifications in a physiologic setup, we optimized and validated a procedure of orthotopically transplanted, perfused, and ventilated single pulmonary transplantation in mice. Methods: C57BL/6 mice served as recipient, with Balb/c as donor. At time of harvest, explanted lungs were perfused with Perfadex, and the heart-lung block excised. Under 30 to 403 magnification, vessels and bronchus were cuffed. Following left thoracotomy in the recipient, hilar structures were incised and cuff-anastomosed with the corresponding donor parts. Allogeneic and syngeneic transplantations (n ¼ 12/group) were performed with a follow-up period of 5 days and up to 90 days, respectively. Results: The success rate of lung transplantation in mice was 87.5% (21/24). Mean cold ischemia time was 32.3 AE 3.7 minutes, and warm ischemia time was 30.8 AE 9.5 minutes. Deaths were due to bleeding during dissection of the hilus and/or caused by thrombosis postoperatively. Allogeneic grafts were rejected by day 5; syngeneic grafts were slightly congested but mainly unchanged up to day 90 posttransplantation. Conclusions: Unilateral lung transplantation in mice can be performed in a standardized and controlled fashion with low mortality, comparable to the rat. Employing transgenic and knockout mice strains, this procedure holds great promise to advance the understanding of immunologic pathways in acute and chronic rejection in a physiologic model of pulmonary transplantation.
Die kostimulatorische Funktion des T-Zell-Antigens (Ag) CD26 ist mit dessen enzymatischer Aktivit... more Die kostimulatorische Funktion des T-Zell-Antigens (Ag) CD26 ist mit dessen enzymatischer Aktivitat (Dipeptidylpeptidase IV, DPP IV) verknupft [1] und wird mit der in-vivo-Immunkompetenz assoziiert [2]. Viele Zytokine, u. a. RANTES, IL-2 und TNF sind Substrate von DPP IV Wir konnten zeigen, das die akute Abstosungsreaktion mit der Auspragung/Enzymaktivitat von CD26 korrelierte. Die Inhibition der spezifischen Enzymaktivitat verhinderte die akute Abstosung und verlangerte das Transplantatuberleben [3]. Ziel dieser Arbeit war die Untersuchung von CD26/DPP IV im Rahmen der Allo-Ag-induzierten Immunantwort bei akuter und akzelerierter Abstosung.
Despite the impact of chronic rejection (CR) on long-term outcomes, clinically relevant experimen... more Despite the impact of chronic rejection (CR) on long-term outcomes, clinically relevant experimental models are sparse, often including a design of subcutaneous implantation of tracheal segments. However, this latter site lacks anatomic correlation, adequate perfusion, and ventilatory function. In this study, we compared the spatial and sequential course of CR in models of orthotopic single lung transplantation (LT) versus heterotopically implanted tracheal segments in rats. We performed 30 orthotopic left single LTs from Fisher 344 (F344) to Wistar Kyoto (WKY) rats for comparison with the outcomes of 3 tracheal segments implanted subcutaneously in every recipient. As a control group, 3 syngeneic tracheal segments were implanted into 12 WKY rats. For histopathologic examinations, tracheal segments and pulmonary allografts were harvested between days 1 and 112 and between weeks 4 and 18, respectively. Allogeneic tracheal segments showed rapid fragmentation of the respiratory epithelium, with complete luminal occlusion by week 4, whereas the lumen in isografts remained unobstructed. In contrast, bronchioles from orthotopically transplanted lungs did not show epithelial changes before week 14. However, marked lymphocytic sequestration into bronchioles occurred by week 8 with sequential destruction of all layers of the small airways, with loss of respiratory epithelium by week 16. Based on the different histomorphologic dynamics of CR, direct comparison between those 2 models is limited. When investigating CR in future studies, initial findings based on tracheal implantation experiments should be expanded in the site of orthotopic pulmonary transplantation.
Macrophages and T cells have a pivotal role in orchestrating the acute lung allograft rejection r... more Macrophages and T cells have a pivotal role in orchestrating the acute lung allograft rejection response. We investigated the spatial and temporal distribution of these immune cells and the synthesis patterns of the T(h)1- and T(h)2-cytokine IL-12 and IL-10 during the early course after transplantation (Tx). Orthotopic single-lung Tx was performed in Lewis to Lewis (syngrafts) and Brown Norway/Lewis F(1) hybrid to Lewis (allografts). Naïve lungs, syngrafts after 5 days and allografts after 3 and 5 days were analyzed for CD68+, CD163+ and CD3+ cells by immunohistochemistry and IL-12 and IL-10 were detected by immunofluorescence. CD68+ macrophages increased in number after allogeneic Tx compared to syngeneic Tx on day 5 (P<.001), CD163+ macrophages sequestrated early around veins (day 3) compared to the accumulation around arteries and bronchioles (P<.001) while CD3+ T cells were scarce. There was a predominance of IL-12 over IL-10 on day 5 after allogeneic Tx (P<.001). CD68+ macrophages were the most abundant cells during acute pulmonary rejection and CD163+ macrophages showed a characteristic distribution pattern over time around vessels and bronchioles. The up-regulation of IL-12 reflects an early response after allo-antigen exposure, indicating a strong impact of the initiation of the T(h)1 pathway at an early phase during acute lung rejection.
European Journal of Cardio-Thoracic Surgery, Jun 1, 2009
The coming of age of lung transplantation is accompanied by an immunosuppressive armamentarium th... more The coming of age of lung transplantation is accompanied by an immunosuppressive armamentarium that has been brought forward from other transplant indications. Widely employed on the basis of few small randomized studies, and mostly single-center experience or empirical expert knowledge, anti-rejection therapeutic strategies in pulmonary transplantation have hardly been rigorously evaluated in large-scale prospective international trials. This review compiles the available findings on the use of current immunosuppressants in clinical lung transplantation, accentuating high level-of-evidence study results. Reporting on recent meeting and registry data, and assembling ongoing relevant trials from international databases, this article serves as an update on the state of the art of immunosuppression in lung transplantation.
We compared the diagnostic accuracy of integrated positron-emission tomography (PET) and computed... more We compared the diagnostic accuracy of integrated positron-emission tomography (PET) and computed tomography (CT) with that of CT alone, that of PET alone, and that of conventional visual correlation of PET and CT in determining the stage of disease in non-small-cell lung cancer. methods In a prospective study, integrated PET-CT was performed in 50 patients with proven or suspected non-small-cell lung cancer. CT and PET alone, visually correlated PET and CT, and integrated PET-CT were evaluated separately, and a tumor-node-metastasis (TNM) stage was assigned on the basis of image analysis. Nodal stations were identified according to the mapping system of the American Thoracic Society. The standard of reference was histopathological assessment of tumor stage and node stage. Extrathoracic metastases were confirmed histopathologically or by at least one other imaging method. A paired sign test was used to compare integrated PET-CT with the other imaging methods. results Integrated PET-CT provided additional information in 20 of 49 patients (41 percent), beyond that provided by conventional visual correlation of PET and CT. Integrated PET-CT had better diagnostic accuracy than the other imaging methods. Tumor staging was significantly more accurate with integrated PET-CT than with CT alone (P=0.001), PET alone (P<0.001), or visual correlation of PET and CT (P=0.013); node staging was also significantly more accurate with integrated PET-CT than with PET alone (P=0.013). In metastasis staging, integrated PET-CT increased the diagnostic certainty in two of eight patients. conclusions Integrated PET-CT improves the diagnostic accuracy of the staging of non-small-cell lung cancer.
Acute allograft rejection (AR) remains a major problem in solid organ transplantation. The pivota... more Acute allograft rejection (AR) remains a major problem in solid organ transplantation. The pivotal mechanism hinges on alloantigen recognition by recipient T helper (T h) cells that differentiate into T h 1 and T h 2. This study investigated the association of mRNA levels of the transcription factors T-box expressed in T cells and GATA-binding protein 3 with the development of T h 1/T h 2-directed immune responses. We investigated the expression of T-bet and GATA-3 mRNA levels and the protein levels of their marker cytokines interleukin (IL)-2 and IL-4 in orthotopically transplanted rat lungs during AR. We observed a nonsignificant increase in T-bet expression following allografting at days 3 and 5 but there was a significant reduction in GATA-3 expression on day 5 compared with controls. The ratio of T-bet to GATA-3 expression showed a trend to increase at day 3 following allografting reaching significance at 5 days. These changes were associated with a significant increase in the expression of IL-2 over IL-4 on days 3 and 5. This study suggests that T h 1 responses play a major role during AR in the rat lung, and that this differentiation can be monitored by measuring mRNA levels of T-bet and GATA-3. A CUTE REJECTION (AR) of a pulmonary allograft continues to markedly impact early morbidity and mortality. Within the first year after transplantation up to 50% of recipients experience at least 1 AR episode warranting treatment. 1 Although the actual risk of death from AR has been declining during the last decade, the incidence of AR episodes constitutes one of the major risk factors for the development of bronchiolitis obliterans, the hallmark of From the Division of Thoracic Surgery (W.
Immunosuppressive effects of human CTLA4Ig in a non-human primate model of allogeneic pancreatic ... more Immunosuppressive effects of human CTLA4Ig in a non-human primate model of allogeneic pancreatic islet transplantation.
This study reports on the potent cytocidal and interleukin-1 releasing properties of Escherichia ... more This study reports on the potent cytocidal and interleukin-1 releasing properties of Escherichia coli hemolysin (ECH) on human monocytes. Nanomolar concentrations of purified ECH (250-2,000 ng/ml) caused rapid and irreversible depletion of cellular ATP to levels below 20% of controls within 60 min. Subcytocidal doses (10-200 ng/ml) of ECH induced rapid release within 60-120 min of large amounts of interleukin 1,8 (IL-1(3) from cultured monocytes. IL-103 release occurred in the presence of actinomycin D and cycloheximide, and was thus probably due to processing and export of intracellular IL-1, precursor. Incubation of toxin-producing E. coli at ratios of only 0.3-3 colony-forming units per monocyte evoked 50% depletion of total cellular ATP within 90 min. Toxin producers also stimulated synthesis and release of large amounts of interleukin 1, but not of tumor necrosis factor within the same time span. In contrast, non-toxin producers caused neither cell death nor rapid interleukin 1 release. Stimulation of rapid interleukin 1 release coupled with potent cytocidal effects on cells of monocytic origin may represent pathogenetically significant events incurred by bacterial strains that produce ECH and related cytolysins.
The use of Cyclosporine A (CsA) as rejection prophylaxis following organ transplantation is limit... more The use of Cyclosporine A (CsA) as rejection prophylaxis following organ transplantation is limited by its nephrotoxicity. CsA induces renal damage that is associated with tubulo-interstitial injury and parenchymal sequestration of macrophages, perpetuating pro-inflammatory processes. Furthermore, CsA exerts a diabetogenic effect by damaging pancreatic islet cell integrity. Continuous Erythropoietin Receptor Activator (CERA) was shown to mediate tissue-protective and anti-inflammatory effects in various settings of organ injury. Here, we investigated the effect of low dose CERA in a model of CsA-induced renal and pancreatic injury. Rats were exposed to medium-dose CsA for 28 days. Low-dose CERA was given to the treatment group (CERA) (n = 6) once per week vs. a CsA-treated control group (CONTROL) (n = 6). The effect of CERA on renal and pancreatic injuries was analyzed by organ function, histology, immunohistochemistry (CD68 +macrophages, insulin), ELISA (TGF-β1) and RT-PCR (TGF-β1, Osteopontin, IL-10). CsA induced functional kidney damage. Low dose CERA did not lead to improved kidney function in the treatment group. However, low dose CERA showed a trend toward upregulation of osteopontin accompanied by increased renal macrophageinfiltration and enhanced parenchymal TGF-β1 and IL-10 when compared to controls. Moreover, CERA treated animals showed amelioration of pancreatic islet cell injury. In this model of acute CsA-mediated renal injury, low dose CERA administration was associated with anti-inflammatory effects and preservation of pancreatic islet cell viability.
Enzymatic activity inhibition of CD26/dipeptidylpeptidase IV (CD26/DPP IV) attenuated short-term ... more Enzymatic activity inhibition of CD26/dipeptidylpeptidase IV (CD26/DPP IV) attenuated short-term post-Tx (transplantation) ischemia-reperfusion injury after 18-hr-ischemia. Here, we investigated the effect of intragraft CD26/DPP IV catalytic inhibition on primary graft dysfunction during 7 day post-Tx, following extended ischemia. A syngeneic rat (LEW [Lewis abstract]) orthotopic lung Tx model was used, grafts exposed to 18 hr cold ischemia before Tx. Controls were flushed and preserved in Perfadex, and harvested after 1 day (CON1) or 7 day (CON7) post-Tx. Investigational groups IN1, IN3, and IN7 grafts were perfused with and stored in Perfadex + inhibitor (AB192) and harvested at 1, 3, and 7 days post-Tx, respectively. Blood gas analysis, peak airway pressure (PAwP), wet/dry weight ratio, myeloperoxidase thiobarbituric acid reactive substances (TBARS), and staining for vasoactive intestinal peptide (VIP) were analyzed. IN1 versus CON1 showed preserved histology, increased pO2 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), lowered PAwP (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), less edema (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and decreased TBARS (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Survival was better for IN7 versus CON7 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). The course of AB192-perfused grafts from 1 to 7 days displayed improved values for pO2 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), PAwP (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), edema (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), TBARS (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), and myeloperoxidase (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Compared with controls, VIP was preserved during 18 hr ischemia in alveolar macrophages (P=0.0001) and respiratory epithelial cells (P=0.001). Perfusion with an inhibitor of CD26/DPP IV enzymatic activity significantly reduced the incidence and severity of pulmonary primary graft dysfunction and enabled recovery after extended ischemia. This is the first report that CD26/DPPIV inhibitor treatment increases local pulmonary VIP levels, which correlate with preserved ventilatory function and pulmonary structural integrity.
Background: Resection for localized bronchiectasis is a well established therapy. However, there ... more Background: Resection for localized bronchiectasis is a well established therapy. However, there is little information on the role of surgery in non-localized bronchiectasis. Methods: Between January 1992 and April 2001, 55 patients without cystic fibrosis underwent resection. Forty-eight patients (mean age 45 (range 23-74) years; 32 women) were available for long-term followup. Twenty-five patients underwent resection for localized disease (group 1) and 23 had bronchiectasis in at least two different lobes (group 2). Results: Thirty-one of the 48 patients were treated by Video Assisted Thoracoscopic Surgery (VATS) resection. There was no 30-day mortality. Mean duration of hospital stay was 10•9 (range 6-31) days in group 1 and 11•1 (range 5-19) days in group 2. Three of 25 patients in group 1 required reoperation. Only minor complications occurred in group 2 (three patients). Mean follow-up for both groups was 37 (range 6-97) months. Twenty-three of 25 patients in group 1 and 16 of 23 in group 2 reported satisfaction at 6 months after the operation. Recurrent infection was noted in three patients in each group. Haemoptysis recurred in only one patient in group 2. Conclusion: The surgical treatment of selected patients with non-localized bronchiectasis was safe and most patients were satisfied with the outcome.
European Journal of Cardio-Thoracic Surgery, Feb 1, 2009
Anastomotic complications following lung transplantation (LuTx) have been described in up to 15% ... more Anastomotic complications following lung transplantation (LuTx) have been described in up to 15% of patients. Challenging to treat, they are associated with high morbidity and a mortality rate of 2-5%. The aim of this study was to analyze the incidence of complications in a consecutive series of bronchial anastomosis after LuTx at our center and to delineate the potential risk factors. Methods: Between 1992 and 2007, 441 bronchial anastomoses were performed in 235 patients. Indications for transplantation were cystic fibrosis (35.7%) emphysema (28.1%) pulmonary fibrosis (12.8%) and pulmonary hypertension (7.7%). There were 206 sequential bilateral and 28 single transplants including lobar engraftments in 20 cases. The donor bronchus was shortened to the plane of the lobar carina including the medial wall of the intermediate bronchus. Peribronchial tissue was left untouched. Anastomosis was carried out using a continuous absorbable running suture (PDS 4/0) at the membranous and interrupted sutures at the cartilaginous part. Six elective surveillance bronchoscopies were done monthly during the first halfyear post-LuTx, with detailed assessment of the pre-and post-anastomotic airways. Results: One-year survival since 2000 was 90.5%. In all 441 anastomoses performed, no significant dehiscence was observed. In one patient, a small fistula was detected and closed surgically on postoperative day five. Fungal membranes were found in 50% of the anastomoses at 1 month and in 14% at 6 months. Discrete narrowing of the anastomotic lumen without need for intervention was found in 4.9% of patients at 1 month and in 2.4% at 6 months. Age, cytomegalovirus status, induction therapy, immunosuppressive regimen, ischemic time, and ventilation time had no influence on bronchial healing. Conclusions: Clinically relevant bronchial anastomotic complications after LuTx can be avoided by use of a simple standardized surgical technique. Aggressive antibiotic and antifungal therapy might play an important supportive role.
The CD26 antigen, one of the major costimulatory molecules in T cell activation, was shown to pos... more The CD26 antigen, one of the major costimulatory molecules in T cell activation, was shown to possess dipeptidyl peptidase IV (DPP IV) activity. Previously, we demonstrated that immunosuppressed kidney transplant patients exhibit lower DPP IV serum activity as compared with healthy individuals. In the present study, we analyzed the role of CD26/DPP IV in the immune cascade triggered by organ transplantation and leading to acute rejection of cardiac allografts in rat recipients. Transplantation of hearts from (Lewis x Brown Norway)F1 donors into Lewis hosts resulted in an early (24 hr) increase in cellular CD26 expression, followed by a rise in DPP IV serum activity, which peaked at day 6, i.e., before the time of actual graft loss. Specific targeting of DPP IV activity with a novel, low-molecular-weight inhibitor of the diphenyl-phosphonate group (prodipine) abrogated acute rejection and prolonged cardiac allograft survival to 14.0+/-0.9 days (P&amp;amp;lt;0.0001). Prodipine treatment prevented the early peak of cellular CD26 expression and thoroughly suppressed systemic DPP IV activity. The inhibition of DPP IV was associated with severely impaired host cytotoxic T lymphocyte responses in vitro. These results demonstrate the role of CD26/DPP IV in alloantigen-mediated immune regulation in vivo and provide the first direct evidence that CD26/DPP IV plays an important role in the mechanism of allograft rejection. The model of targeting CD26/DPP IV may reveal essential interactions on the level of costimulatory alternate T cell activation pathways, allowing a more subtle approach for more selective immunosuppression in transplant recipients.
The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymat... more The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymatic properties. Catalytically, it functions as an exopeptidase, modulating biological activity of key chemokines and peptides. Here we investigated the effect of organ-specific inhibition of DPP IV catalytic activity on ischemia/reperfusion injury after extended ischemia in the mouse model of orthotopic single lung transplantation. C57BL/6 mice were syngeneically, transplanted, grafts were perfused and stored in Perfadex with (treated) or without (control) a DPP IV enzymatic activity inhibitor (AB192). Transplantation was performed after 18 h cold ischemia time; following 2-h reperfusion, grafts were analyzed for oxygenation, thiobarbituric acid-reactive substances, histomorphology, and immunohistochemistry was performed for leukocyte Ag 6, myeloperoxidase, hemoxygenase 1, vasoactive intestinal protein (VIP), and real-time PCR for VIP. Treatment with the DPP IV inhibitor AB192 resulted in significant improvement of gas exchange, less lipid oxidation, preservation of parenchymal ultrastructure, reduced neutrophil infiltration, reduced myeloperoxidase expression, increased hemoxygenase 1 expression, pronounced expression of VIP in alveolar macrophages and increased mRNA expression of VIP. Inhibition of intragraft DPP IV catalytic activity with AB192 strikingly ameliorates ischemia/reperfusion injury after extended ischemia. Furthermore, preservation of endogenous intragraft VIP levels correlate with maintaining lung function and structural integrity.
European Journal of Cardio-Thoracic Surgery, Aug 1, 2003
Objective: To date numerous attempts have been undertaken to conquer the challenging problem of r... more Objective: To date numerous attempts have been undertaken to conquer the challenging problem of reconstructing long segmental tracheal defects, as yet without lasting success. Recently, employing concepts of tissue engineering in animals, cartilage-like constructs were transplanted in vivo. However, both the feasibility of fabricating tracheal replacements and the use of human tracheal chondrocytes (HTC) for tissue engineering are still under investigation. In this study, we optimized isolation and cultivation techniques for human tracheal cartilage, assessing the feasibility of seeding these cells onto a novel, three-dimensional (3-D) polyester-urethane polymer (DegraPol w). Methods: Human tracheal cartilage was harvested from the trachea of lung donors, digested in 0.3% collagenase II, and the condrocytes serially passaged every 7-9 days. Cells were also cultivated over agar plate during the total 6-8 weeks expansion phase. Thereafter, chondrocytes were seeded onto DegraPol w (pore sizes 150-200 mm) with a seeding density of 2:4 £ 10 7 =ml, and chondrocyte-polymer constructs maintained during in vitro static culture. Results: HTC displayed stable proliferation kinetics in monolayer culture with positive expression of collagen type II. Following polymer seeding, both cellular proliferation and extracellular matrix (ECM) production, as measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and glycosaminoglycan assays, continued over extended culture. Active growth of HTC on DegraPol w was further demonstrated by Alcian blue staining, with the histomorphological appearance of the construct resembling that of native cartilage. Scanning electron microscopy showed chondrocyte growth and ECM synthesis both on the surface and inside the porous scaffold, with a dense cell layer on the surface of the scaffold and a lower cell distribution in the scaffold's interior. Conclusions: The harvested chondrocytes from human trachea cartilage expand well in vitro and possess the ability to form new cartilage-like tissue when seeded onto DegraPol w matrix. However, improved culture conditions are needed to permit cellular growth throughout cell-polymer constructs.
The Journal of Thoracic and Cardiovascular Surgery, Feb 1, 2009
Progress in studying acute and chronic pulmonary allograft rejection has been hampered by the lac... more Progress in studying acute and chronic pulmonary allograft rejection has been hampered by the lack of feasible experimental animal transplantation models. Contemporary approaches are limited by anatomic applicability (heterotopic tracheal implantation) and lack of genetic variability (rat model). To utilize the breadth of available genetic modifications in a physiologic setup, we optimized and validated a procedure of orthotopically transplanted, perfused, and ventilated single pulmonary transplantation in mice. Methods: C57BL/6 mice served as recipient, with Balb/c as donor. At time of harvest, explanted lungs were perfused with Perfadex, and the heart-lung block excised. Under 30 to 403 magnification, vessels and bronchus were cuffed. Following left thoracotomy in the recipient, hilar structures were incised and cuff-anastomosed with the corresponding donor parts. Allogeneic and syngeneic transplantations (n ¼ 12/group) were performed with a follow-up period of 5 days and up to 90 days, respectively. Results: The success rate of lung transplantation in mice was 87.5% (21/24). Mean cold ischemia time was 32.3 AE 3.7 minutes, and warm ischemia time was 30.8 AE 9.5 minutes. Deaths were due to bleeding during dissection of the hilus and/or caused by thrombosis postoperatively. Allogeneic grafts were rejected by day 5; syngeneic grafts were slightly congested but mainly unchanged up to day 90 posttransplantation. Conclusions: Unilateral lung transplantation in mice can be performed in a standardized and controlled fashion with low mortality, comparable to the rat. Employing transgenic and knockout mice strains, this procedure holds great promise to advance the understanding of immunologic pathways in acute and chronic rejection in a physiologic model of pulmonary transplantation.
Die kostimulatorische Funktion des T-Zell-Antigens (Ag) CD26 ist mit dessen enzymatischer Aktivit... more Die kostimulatorische Funktion des T-Zell-Antigens (Ag) CD26 ist mit dessen enzymatischer Aktivitat (Dipeptidylpeptidase IV, DPP IV) verknupft [1] und wird mit der in-vivo-Immunkompetenz assoziiert [2]. Viele Zytokine, u. a. RANTES, IL-2 und TNF sind Substrate von DPP IV Wir konnten zeigen, das die akute Abstosungsreaktion mit der Auspragung/Enzymaktivitat von CD26 korrelierte. Die Inhibition der spezifischen Enzymaktivitat verhinderte die akute Abstosung und verlangerte das Transplantatuberleben [3]. Ziel dieser Arbeit war die Untersuchung von CD26/DPP IV im Rahmen der Allo-Ag-induzierten Immunantwort bei akuter und akzelerierter Abstosung.
Despite the impact of chronic rejection (CR) on long-term outcomes, clinically relevant experimen... more Despite the impact of chronic rejection (CR) on long-term outcomes, clinically relevant experimental models are sparse, often including a design of subcutaneous implantation of tracheal segments. However, this latter site lacks anatomic correlation, adequate perfusion, and ventilatory function. In this study, we compared the spatial and sequential course of CR in models of orthotopic single lung transplantation (LT) versus heterotopically implanted tracheal segments in rats. We performed 30 orthotopic left single LTs from Fisher 344 (F344) to Wistar Kyoto (WKY) rats for comparison with the outcomes of 3 tracheal segments implanted subcutaneously in every recipient. As a control group, 3 syngeneic tracheal segments were implanted into 12 WKY rats. For histopathologic examinations, tracheal segments and pulmonary allografts were harvested between days 1 and 112 and between weeks 4 and 18, respectively. Allogeneic tracheal segments showed rapid fragmentation of the respiratory epithelium, with complete luminal occlusion by week 4, whereas the lumen in isografts remained unobstructed. In contrast, bronchioles from orthotopically transplanted lungs did not show epithelial changes before week 14. However, marked lymphocytic sequestration into bronchioles occurred by week 8 with sequential destruction of all layers of the small airways, with loss of respiratory epithelium by week 16. Based on the different histomorphologic dynamics of CR, direct comparison between those 2 models is limited. When investigating CR in future studies, initial findings based on tracheal implantation experiments should be expanded in the site of orthotopic pulmonary transplantation.
Macrophages and T cells have a pivotal role in orchestrating the acute lung allograft rejection r... more Macrophages and T cells have a pivotal role in orchestrating the acute lung allograft rejection response. We investigated the spatial and temporal distribution of these immune cells and the synthesis patterns of the T(h)1- and T(h)2-cytokine IL-12 and IL-10 during the early course after transplantation (Tx). Orthotopic single-lung Tx was performed in Lewis to Lewis (syngrafts) and Brown Norway/Lewis F(1) hybrid to Lewis (allografts). Naïve lungs, syngrafts after 5 days and allografts after 3 and 5 days were analyzed for CD68+, CD163+ and CD3+ cells by immunohistochemistry and IL-12 and IL-10 were detected by immunofluorescence. CD68+ macrophages increased in number after allogeneic Tx compared to syngeneic Tx on day 5 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001), CD163+ macrophages sequestrated early around veins (day 3) compared to the accumulation around arteries and bronchioles (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001) while CD3+ T cells were scarce. There was a predominance of IL-12 over IL-10 on day 5 after allogeneic Tx (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;.001). CD68+ macrophages were the most abundant cells during acute pulmonary rejection and CD163+ macrophages showed a characteristic distribution pattern over time around vessels and bronchioles. The up-regulation of IL-12 reflects an early response after allo-antigen exposure, indicating a strong impact of the initiation of the T(h)1 pathway at an early phase during acute lung rejection.
European Journal of Cardio-Thoracic Surgery, Jun 1, 2009
The coming of age of lung transplantation is accompanied by an immunosuppressive armamentarium th... more The coming of age of lung transplantation is accompanied by an immunosuppressive armamentarium that has been brought forward from other transplant indications. Widely employed on the basis of few small randomized studies, and mostly single-center experience or empirical expert knowledge, anti-rejection therapeutic strategies in pulmonary transplantation have hardly been rigorously evaluated in large-scale prospective international trials. This review compiles the available findings on the use of current immunosuppressants in clinical lung transplantation, accentuating high level-of-evidence study results. Reporting on recent meeting and registry data, and assembling ongoing relevant trials from international databases, this article serves as an update on the state of the art of immunosuppression in lung transplantation.
We compared the diagnostic accuracy of integrated positron-emission tomography (PET) and computed... more We compared the diagnostic accuracy of integrated positron-emission tomography (PET) and computed tomography (CT) with that of CT alone, that of PET alone, and that of conventional visual correlation of PET and CT in determining the stage of disease in non-small-cell lung cancer. methods In a prospective study, integrated PET-CT was performed in 50 patients with proven or suspected non-small-cell lung cancer. CT and PET alone, visually correlated PET and CT, and integrated PET-CT were evaluated separately, and a tumor-node-metastasis (TNM) stage was assigned on the basis of image analysis. Nodal stations were identified according to the mapping system of the American Thoracic Society. The standard of reference was histopathological assessment of tumor stage and node stage. Extrathoracic metastases were confirmed histopathologically or by at least one other imaging method. A paired sign test was used to compare integrated PET-CT with the other imaging methods. results Integrated PET-CT provided additional information in 20 of 49 patients (41 percent), beyond that provided by conventional visual correlation of PET and CT. Integrated PET-CT had better diagnostic accuracy than the other imaging methods. Tumor staging was significantly more accurate with integrated PET-CT than with CT alone (P=0.001), PET alone (P<0.001), or visual correlation of PET and CT (P=0.013); node staging was also significantly more accurate with integrated PET-CT than with PET alone (P=0.013). In metastasis staging, integrated PET-CT increased the diagnostic certainty in two of eight patients. conclusions Integrated PET-CT improves the diagnostic accuracy of the staging of non-small-cell lung cancer.
Acute allograft rejection (AR) remains a major problem in solid organ transplantation. The pivota... more Acute allograft rejection (AR) remains a major problem in solid organ transplantation. The pivotal mechanism hinges on alloantigen recognition by recipient T helper (T h) cells that differentiate into T h 1 and T h 2. This study investigated the association of mRNA levels of the transcription factors T-box expressed in T cells and GATA-binding protein 3 with the development of T h 1/T h 2-directed immune responses. We investigated the expression of T-bet and GATA-3 mRNA levels and the protein levels of their marker cytokines interleukin (IL)-2 and IL-4 in orthotopically transplanted rat lungs during AR. We observed a nonsignificant increase in T-bet expression following allografting at days 3 and 5 but there was a significant reduction in GATA-3 expression on day 5 compared with controls. The ratio of T-bet to GATA-3 expression showed a trend to increase at day 3 following allografting reaching significance at 5 days. These changes were associated with a significant increase in the expression of IL-2 over IL-4 on days 3 and 5. This study suggests that T h 1 responses play a major role during AR in the rat lung, and that this differentiation can be monitored by measuring mRNA levels of T-bet and GATA-3. A CUTE REJECTION (AR) of a pulmonary allograft continues to markedly impact early morbidity and mortality. Within the first year after transplantation up to 50% of recipients experience at least 1 AR episode warranting treatment. 1 Although the actual risk of death from AR has been declining during the last decade, the incidence of AR episodes constitutes one of the major risk factors for the development of bronchiolitis obliterans, the hallmark of From the Division of Thoracic Surgery (W.
Immunosuppressive effects of human CTLA4Ig in a non-human primate model of allogeneic pancreatic ... more Immunosuppressive effects of human CTLA4Ig in a non-human primate model of allogeneic pancreatic islet transplantation.
This study reports on the potent cytocidal and interleukin-1 releasing properties of Escherichia ... more This study reports on the potent cytocidal and interleukin-1 releasing properties of Escherichia coli hemolysin (ECH) on human monocytes. Nanomolar concentrations of purified ECH (250-2,000 ng/ml) caused rapid and irreversible depletion of cellular ATP to levels below 20% of controls within 60 min. Subcytocidal doses (10-200 ng/ml) of ECH induced rapid release within 60-120 min of large amounts of interleukin 1,8 (IL-1(3) from cultured monocytes. IL-103 release occurred in the presence of actinomycin D and cycloheximide, and was thus probably due to processing and export of intracellular IL-1, precursor. Incubation of toxin-producing E. coli at ratios of only 0.3-3 colony-forming units per monocyte evoked 50% depletion of total cellular ATP within 90 min. Toxin producers also stimulated synthesis and release of large amounts of interleukin 1, but not of tumor necrosis factor within the same time span. In contrast, non-toxin producers caused neither cell death nor rapid interleukin 1 release. Stimulation of rapid interleukin 1 release coupled with potent cytocidal effects on cells of monocytic origin may represent pathogenetically significant events incurred by bacterial strains that produce ECH and related cytolysins.
The use of Cyclosporine A (CsA) as rejection prophylaxis following organ transplantation is limit... more The use of Cyclosporine A (CsA) as rejection prophylaxis following organ transplantation is limited by its nephrotoxicity. CsA induces renal damage that is associated with tubulo-interstitial injury and parenchymal sequestration of macrophages, perpetuating pro-inflammatory processes. Furthermore, CsA exerts a diabetogenic effect by damaging pancreatic islet cell integrity. Continuous Erythropoietin Receptor Activator (CERA) was shown to mediate tissue-protective and anti-inflammatory effects in various settings of organ injury. Here, we investigated the effect of low dose CERA in a model of CsA-induced renal and pancreatic injury. Rats were exposed to medium-dose CsA for 28 days. Low-dose CERA was given to the treatment group (CERA) (n = 6) once per week vs. a CsA-treated control group (CONTROL) (n = 6). The effect of CERA on renal and pancreatic injuries was analyzed by organ function, histology, immunohistochemistry (CD68 +macrophages, insulin), ELISA (TGF-β1) and RT-PCR (TGF-β1, Osteopontin, IL-10). CsA induced functional kidney damage. Low dose CERA did not lead to improved kidney function in the treatment group. However, low dose CERA showed a trend toward upregulation of osteopontin accompanied by increased renal macrophageinfiltration and enhanced parenchymal TGF-β1 and IL-10 when compared to controls. Moreover, CERA treated animals showed amelioration of pancreatic islet cell injury. In this model of acute CsA-mediated renal injury, low dose CERA administration was associated with anti-inflammatory effects and preservation of pancreatic islet cell viability.
Enzymatic activity inhibition of CD26/dipeptidylpeptidase IV (CD26/DPP IV) attenuated short-term ... more Enzymatic activity inhibition of CD26/dipeptidylpeptidase IV (CD26/DPP IV) attenuated short-term post-Tx (transplantation) ischemia-reperfusion injury after 18-hr-ischemia. Here, we investigated the effect of intragraft CD26/DPP IV catalytic inhibition on primary graft dysfunction during 7 day post-Tx, following extended ischemia. A syngeneic rat (LEW [Lewis abstract]) orthotopic lung Tx model was used, grafts exposed to 18 hr cold ischemia before Tx. Controls were flushed and preserved in Perfadex, and harvested after 1 day (CON1) or 7 day (CON7) post-Tx. Investigational groups IN1, IN3, and IN7 grafts were perfused with and stored in Perfadex + inhibitor (AB192) and harvested at 1, 3, and 7 days post-Tx, respectively. Blood gas analysis, peak airway pressure (PAwP), wet/dry weight ratio, myeloperoxidase thiobarbituric acid reactive substances (TBARS), and staining for vasoactive intestinal peptide (VIP) were analyzed. IN1 versus CON1 showed preserved histology, increased pO2 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), lowered PAwP (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), less edema (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and decreased TBARS (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Survival was better for IN7 versus CON7 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). The course of AB192-perfused grafts from 1 to 7 days displayed improved values for pO2 (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), PAwP (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01), edema (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), TBARS (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), and myeloperoxidase (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Compared with controls, VIP was preserved during 18 hr ischemia in alveolar macrophages (P=0.0001) and respiratory epithelial cells (P=0.001). Perfusion with an inhibitor of CD26/DPP IV enzymatic activity significantly reduced the incidence and severity of pulmonary primary graft dysfunction and enabled recovery after extended ischemia. This is the first report that CD26/DPPIV inhibitor treatment increases local pulmonary VIP levels, which correlate with preserved ventilatory function and pulmonary structural integrity.
Background: Resection for localized bronchiectasis is a well established therapy. However, there ... more Background: Resection for localized bronchiectasis is a well established therapy. However, there is little information on the role of surgery in non-localized bronchiectasis. Methods: Between January 1992 and April 2001, 55 patients without cystic fibrosis underwent resection. Forty-eight patients (mean age 45 (range 23-74) years; 32 women) were available for long-term followup. Twenty-five patients underwent resection for localized disease (group 1) and 23 had bronchiectasis in at least two different lobes (group 2). Results: Thirty-one of the 48 patients were treated by Video Assisted Thoracoscopic Surgery (VATS) resection. There was no 30-day mortality. Mean duration of hospital stay was 10•9 (range 6-31) days in group 1 and 11•1 (range 5-19) days in group 2. Three of 25 patients in group 1 required reoperation. Only minor complications occurred in group 2 (three patients). Mean follow-up for both groups was 37 (range 6-97) months. Twenty-three of 25 patients in group 1 and 16 of 23 in group 2 reported satisfaction at 6 months after the operation. Recurrent infection was noted in three patients in each group. Haemoptysis recurred in only one patient in group 2. Conclusion: The surgical treatment of selected patients with non-localized bronchiectasis was safe and most patients were satisfied with the outcome.
European Journal of Cardio-Thoracic Surgery, Feb 1, 2009
Anastomotic complications following lung transplantation (LuTx) have been described in up to 15% ... more Anastomotic complications following lung transplantation (LuTx) have been described in up to 15% of patients. Challenging to treat, they are associated with high morbidity and a mortality rate of 2-5%. The aim of this study was to analyze the incidence of complications in a consecutive series of bronchial anastomosis after LuTx at our center and to delineate the potential risk factors. Methods: Between 1992 and 2007, 441 bronchial anastomoses were performed in 235 patients. Indications for transplantation were cystic fibrosis (35.7%) emphysema (28.1%) pulmonary fibrosis (12.8%) and pulmonary hypertension (7.7%). There were 206 sequential bilateral and 28 single transplants including lobar engraftments in 20 cases. The donor bronchus was shortened to the plane of the lobar carina including the medial wall of the intermediate bronchus. Peribronchial tissue was left untouched. Anastomosis was carried out using a continuous absorbable running suture (PDS 4/0) at the membranous and interrupted sutures at the cartilaginous part. Six elective surveillance bronchoscopies were done monthly during the first halfyear post-LuTx, with detailed assessment of the pre-and post-anastomotic airways. Results: One-year survival since 2000 was 90.5%. In all 441 anastomoses performed, no significant dehiscence was observed. In one patient, a small fistula was detected and closed surgically on postoperative day five. Fungal membranes were found in 50% of the anastomoses at 1 month and in 14% at 6 months. Discrete narrowing of the anastomotic lumen without need for intervention was found in 4.9% of patients at 1 month and in 2.4% at 6 months. Age, cytomegalovirus status, induction therapy, immunosuppressive regimen, ischemic time, and ventilation time had no influence on bronchial healing. Conclusions: Clinically relevant bronchial anastomotic complications after LuTx can be avoided by use of a simple standardized surgical technique. Aggressive antibiotic and antifungal therapy might play an important supportive role.
The CD26 antigen, one of the major costimulatory molecules in T cell activation, was shown to pos... more The CD26 antigen, one of the major costimulatory molecules in T cell activation, was shown to possess dipeptidyl peptidase IV (DPP IV) activity. Previously, we demonstrated that immunosuppressed kidney transplant patients exhibit lower DPP IV serum activity as compared with healthy individuals. In the present study, we analyzed the role of CD26/DPP IV in the immune cascade triggered by organ transplantation and leading to acute rejection of cardiac allografts in rat recipients. Transplantation of hearts from (Lewis x Brown Norway)F1 donors into Lewis hosts resulted in an early (24 hr) increase in cellular CD26 expression, followed by a rise in DPP IV serum activity, which peaked at day 6, i.e., before the time of actual graft loss. Specific targeting of DPP IV activity with a novel, low-molecular-weight inhibitor of the diphenyl-phosphonate group (prodipine) abrogated acute rejection and prolonged cardiac allograft survival to 14.0+/-0.9 days (P&amp;amp;lt;0.0001). Prodipine treatment prevented the early peak of cellular CD26 expression and thoroughly suppressed systemic DPP IV activity. The inhibition of DPP IV was associated with severely impaired host cytotoxic T lymphocyte responses in vitro. These results demonstrate the role of CD26/DPP IV in alloantigen-mediated immune regulation in vivo and provide the first direct evidence that CD26/DPP IV plays an important role in the mechanism of allograft rejection. The model of targeting CD26/DPP IV may reveal essential interactions on the level of costimulatory alternate T cell activation pathways, allowing a more subtle approach for more selective immunosuppression in transplant recipients.
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Papers by Stephan Korom