HMGB1 blockade significantly improves luminal fibrous obliteration in a murine model of bronchiolitis obliterans syndrome

BackgroundAlthough high-mobility group box-1 (HMGB1), which is a nuclear protein, was reported to enhance the allogeneic responses in transplantation, the effect of HMGB1 on bronchiolitis obliterans syndrome (BOS) is unknown.MethodsA murine heterotopic tracheal transplantation model was used. Protein concentrations of HMGB1, interferon-γ (IFN-γ), interleukin (IL)-10, and IL-17 were analyzed in the isografts, allografts, controls, and HMGB1-neutralizing antibody administered allografts (n = 6; Days 1, 3, 5, 7, 14, 21, and 28). The luminal fibrous occlusion was analyzed (n = 6; Days 7, 14, 21, and 28). Infiltrating CD8 and CD4 T lymphocytes around the allografts and serum levels of IFN-γ and IL-10 were evaluated (n = 6; Day 7).ResultsThe HMGB1 levels in the allografts were significantly increased compared with the isografts at Day 7. HMGB1 blockade did not change the IL-17 level, but decreased the IFN-γ/IL-10 ratio in the early phase (Days 5 and 7) and significantly improved the fibrous occlusion in the late phase (Days 14, 21, and 28). HMGB1 blockade significantly suppressed the CD8 T lymphocytes infiltration and decreased the serum IFN-γ/IL-10 ratio compared with the control at Day 7.ConclusionsHMGB1 may be a trigger of the BOS pathogenesis and candidate target for the treatment of the disease.     

Attenuation of airway obliteration by ciprofloxacin in experimental posttransplant bronchiolitis obliterans

BACKGROUND: Ciprofloxacin is widely used to treat respiratory tract infections. Like other fluoroquinolones, ciprofloxacin has immunomodulatory effects; however, it is unknown whether these effects are beneficial in the setting of lung transplantation. We investigated potential immunomodulatory effects of ciprofloxacin in a model of posttransplant bronchiolitis obliterans. METHODS: The heterotopic tracheal transplantation model in rats was used. Three groups received ciprofloxacin and underwent different immunosuppressive regimens of cyclosporine A, that is, no immunosuppression, insufficient immunosuppression, or low-dose immunosuppression. Three groups underwent the same immunosuppressive regimen but had no ciprofloxacin treatment. Tracheas were harvested after 21 days and examined with respect to histology and expression of selected cytokines. RESULTS: The allografts of animals treated with ciprofloxacin showed less airway obliteration compared with allografts of untreated animals. When combined with low-dose immunosuppression ciprofloxacin showed beneficial effects in preventing airway obliteration and rejection of the respiratory epithelium. Cytokine gene expression of the allografts treated with ciprofloxacin was higher with respect to transforming growth factor-beta and equal with respect to tumor necrosis factor-alpha and interferon-gamma compared with controls. When applied in combination with cyclosporine A, ciprofloxacin lowered the expression of transforming growth factor-beta and tumor necrosis factor-alpha and increased interferon-gamma expression. CONCLUSION: Ciprofloxacin attenuates airway rejection after tracheal transplantation. Genetic expression of mediators that are known to play an important role in mediating rejection in this model supports an immunomodulatory and antifibrotic role of ciprofloxacin. These findings suggest that further clinical studies are needed to investigate whether ciprofloxacin in addition to its bactericidal effect might be beneficial in the treatment of human posttransplant bronchiolitis obliterans.     

Prevention of small airway obliteration in a swine heterotopic lung allograft model.

BACKGROUND: In our swine model of obliterative bronchiolitis preventing obliteration by the standard immunosuppression with cyclosporine, methylprednisolone, and azathioprine was not successful. The purpose of this study was to test the ability of a new immunosuppressive regimen to prevent alloimmune reaction and obliteration of the allografts. This regimen includes the novel macrolide SDZ RAD, i.e., 40-O-(2hydroxyethyl)-rapamycin. METHODS: Donor lung allografts of 1 cm3 were implanted sub-cutaneously into 11 random-bred non-related domestic pigs receiving daily oral cyclosporine (10 mg/kg) and methylprednisolone (20 mg). In addition, the animals received either oral azathioprine (2 mg/kg) (Group 1) or oral SDZ RAD (1.5 mg/kg) (Group 2). Histologic alterations were graded from 0 to 3 based on repeatedly removed implants during a follow-up period of 3 months. RESULTS: Total epithelial destruction and permanent luminal obliteration occurred within 37 days in Group 1. After an initial grade of 2.3+/-0.3 destruction, epithelial recovery was evident in Group 2 (P < 0.01), and the bronchi stayed patent. Cartilaginous destruction was milder in Group 2 (P < 0.05) than in Group 1, but chondrocytic proliferation was more intense (P < 0.05). Alveolar tissue and native structures of the bronchial wall were destroyed in Group 1, but preserved in Group 2 with total recovery after a mild-grade initial necrosis. CONCLUSIONS: Unlike the standard triple therapy, SDZ RAD combined with cyclosporine and methylprednisolone preserves the pulmonary allografts and prevents epithelial destruction and subsequent luminal obliteration. This suggests that this regimen might efficiently suppress obliterative bronchiolitis and improve long-term results in lung transplant recipients.     

Blocking the CD28-B7 T-cell costimulatory pathway abrogates the development of obliterative bronchiolitis in a murine heterotopic airway model

BACKGROUND: CTLA4IgG that binds to B7 effectively inhibits the signaling of CD28/B7 pathway and induces antigen-specific T-cell unresponsiveness in vitro and in vivo. We examined whether the development of obliterative bronchiolitis in a murine heterotopic airway transplantation model is T cell dependent and whether CTLA4IgG abrogates the development of obliterative bronchiolitis. METHODS: Tracheae with main bronchi from C3H/He (H2k), BALB/C (H2d), or C57BL/6 (H2b) mice were transplanted heterotopically into subcutaneous pockets on the backs of BALB/C or BALB/C nu/nu mice on day 0. Recipient mice were untreated or intraperitoneally treated with either CTLA4IgG or human IgG with different time and dose schedules. RESULTS: The development of obliterative bronchiolitis, which leads to luminal obliteration by fibrous tissue in a murine heterotopic airway transplantation model, was T cell dependent and the development of obliterative bronchiolitis was significantly abrogated by the CTLA4IgG treatment. However, the normal ciliated columnar respiratory epithelial cells in allografts were lost and replaced by flattened attenuated epithelial cells even after the CTLA4IgG treatment. We further demonstrated that CTLA4IgG treatment did not result in the induction of donor-specific unresponsiveness. CONCLUSIONS: We demonstrated that the development of obliterative bronchiolitis in a murine heterotopic airway model involves both CD28/B7-dependent and -independent processes. The luminal obliteration by fibrous tissue is clearly CD28/B7 dependent and can be inhibited by CTLA4IgG. The luminal obliteration of allografted trachea by fibrous tissues and the loss of ciliated columnar respiratory epithelial cells represent distinct disease processes.     

Risk factors for bronchiolitis obliterans: a systematic review of recent publications.

BACKGROUND: Obliterative bronchiolitis remains the major limitation to long-term survival after lung transplantation. A thorough understanding of the factors that confer high risk of developing obliterative bronchiolitis or its physiologic surrogate bronchiolitis obliterans syndrome is important to help define therapeutic strategies. METHODS: We performed a systematic review of studies published since the beginning of 1990. The review excluded non-human studies, publications before 1990, small (less than 25 patients) studies that were predominantly concerned with investigating the pathogenesis of obliterative bronchiolitis, studies solely concerned with diagnosis or treatment of obliterative bronchiolitis, and overlapping studies from the same center. Onset of bronchiolitis obliterans syndrome or obliterative bronchiolitis was the outcome of interest. RESULTS: Acute rejection plays an important role in obliterative bronchiolitis and bronchiolitis obliterans syndrome onset, and late rejection is a significant risk factor. Lymphocytic bronchitis/bronchiolitis is also a risk factor, with some evidence that late onset is associated with greater risk. The effects of cytomegalovirus, other infectious organisms, and human leukocyte antigen matching are less clear and require further confirmation. There is little evidence that recipient and donor characteristics play a major role. CONCLUSIONS: This systematic review supports the view that obliterative bronchiolitis arises from alloimmunologic injury marked by clinically apparent acute rejection episodes and that inflammatory conditions, including viral infections or ischemic injury, may also play a role. Implications for therapy are discussed.     

大鼠供肾转染反义ERK2基因减缓肾移植后慢性移植肾肾病的作用及机制

目的 研究腺病毒介导的反义ERK2(A-dant-ERl(2)基因转染供肾对减缓肾移植后发生慢性移植肾肾病(CAN)的作用及机制.方法 建立大鼠间肾移植模型.按供肾移植前处理方式的不同分为对照组、空载病毒组和基因转染组,每组6只.对照组供肾灌注无菌HTK液0.5 ml,空载病毒组供肾灌注含5x109>pfu LaeZ基因腺病毒(Ad-LacZ)的HTK液0.5 ml,基因转染组供肾灌注含5x 109>pfu Adanti-ERK2的HTK液0.5 ml.肾移植术后24周行移植肾的病理学观察,免疫组织化学法观察肾小管上皮细胞表面标志蛋白E-Cadherin、Vimentin、TβRⅠ的表达以及CD4+、CD8+T淋巴细胞和ED-1+细胞的浸润情况;酶联免疫法检测受者血清中转化生长因子β1>(TGF-β1>)的含量.结果 肾移植术后24周,对照组和空载病毒组移植肾呈CAN表现;肾小球硬化,肾小管萎缩明显,伴严重间质纤维化以及明显的CD4+、CD8+T淋巴细胞和ED-1+细胞浸润;病变区肾小管上皮细胞E-Cadherin表达减少,Vimentin、TβRⅠ表达显著增多.基因转染组移植肾间质内仅有少量CD4+、CD8+T淋巴细胞和ED-1+细胞浸润;肾小管上皮细胞E-Cadherin表达正常.对照组和空载病毒组血清中TGF-β1>,含量明显高于基因转染组.结论 Adanti-ERK2基因转染移植肾可减缓CAN的发生,对移植肾具有保护作用.这种保护机制可能与减少炎症细胞的浸润、下调TGF-β1>,等致纤维化因子的表达以及抑制肾小管上皮细胞向间充质细胞的转化有关.     

Azithromycin reduces airway inflammation in a murine model of lung ischaemia reperfusion injury.

Clinical studies revealed that azithromycin reduces airway neutrophilia during chronic rejection after lung transplantation. Our aim was to investigate the possible effect of azithromycin on ischaemia-reperfusion injury. Azithromycin or water was administered to mice every other day during 2 weeks (n = 6/group). On the 14th day, the left lung was clamped to induce ischaemia (90 min). In two additional groups, animals underwent the same protocol, followed by 4 h of reperfusion. Two control groups were included with thoracotomy only. Inflammatory parameters and oxidative stress were measured in broncho-alveolar lavage of the left lung. Leukocytes, lymphocytes, neutrophils, 8-isoprostane and IL-1beta levels after ischaemia and reperfusion were significantly reduced in mice treated with azithromycin. There was a trend towards lower IL-6 and KC levels. A significant correlation was seen between 8-isoprostanes and neutrophils (Pearson r = 0.72; P = 0.0086), IL-6 (Pearson r = 0.84; P = 0.0006), KC (Pearson r = 0.88; P = 0.0002) and IL-1beta (Pearson r = 0.62; P = 0.0326). We conclude (i) that azithromycin reduces inflammation and oxidative stress in our IRI model, and (ii) that oxidative stress is correlated with the number of neutrophils and IL-6, KC and IL-1beta levels after ischaemia and reperfusion. Azithromycin should be further investigated as a novel drug to prevent lung ischaemia-reperfusion injury.     

Interleukin-17 stimulates release of interleukin-8 by human airway smooth muscle cells in vitro: a potential role for interleukin-17 and airway smooth muscle cells in bronchiolitis obliterans syndrome.

Bronchiolitis obliterans syndrome is the major constraint on the long-term survival after lung transplantation. Both neutrophils and interleukin (IL)-8, a potent neutrophil attractant, have been shown to play an important role in the pathophysiology of obliterative bronchiolitis. We investigated the potential role of human airway smooth muscle cells in obliterative bronchiolitis by studying their release of IL-8 after stimulation with IL-17, a novel T-cell-derived chemokine capable of attracting and activating neutrophils. We demonstrated a significant increase in IL-8 release, reaching a concentration of 86.6 ng/ml (SEM 1.9 ng/ml) with 100 ng/ml IL-17 (p < 0.01, n = 4), as compared with non-stimulated cells. This IL-17-mediated IL-8 release could not be inhibited by dexamethasone. We conclude that human airway smooth muscle cells may play an important pro-inflammatory role in neutrophilic inflammatory diseases such as chronic rejection after lung transplantation; furthermore, IL-17 may be the link between lymphocytes and neutrophils.     

Growth factor expression in a murine model of cryoglobulinemia

BACKGROUND: Increased expression of growth factors including platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) are thought to play pivotal roles during mesangial expansion and glomerulosclerosis. Thymic stromal lymphopoietin (TSLP) transgenic mice develop mixed cryoglobulinemia and a membranoproliferative glomerulonephritis (MPGN). Here we describe the renal expression of isoforms of PDGF and TGF-beta in relation to changes in extracellular matrix (ECM) components and markers of cell proliferation and activation in this model. METHODS: A total of 123 mice, including 61 TSLP transgenic mice and 62 wild-type controls, were sacrificed at defined intervals. PDGF-A chain, -B chain, PDGF alpha- and beta-receptor (beta-R) and TGF-beta1 mRNA were analyzed by in situ hybridization. Expression of alpha smooth muscle actin (alphaSMA), collagen type I, collagen type IV, laminin, and a marker of proliferating cells (PCNA) were assessed by immunohistochemistry. Slides also were studied by combined immunohistochemistry and in situ hybridization with an antibody that recognizes monocytes/macrophage and with riboprobes that detect PDGF B-chain, PDGF beta-R or TGF-beta1 mRNA. RESULTS: Increased numbers of proliferating glomerular cells appeared early in the disease course, associated with de novo expression of alphaSMA. Expression of PDGF B-chain and beta-R mRNA was increased in the mesangium and in parietal epithelial cells of TSLP transgenic mice and correlated with the number of PCNA positive cells. Increased TGF-beta1 mRNA expression paralleled the deposition of type IV collagen. A significant proportion of Mac-2 positive macrophages expressed TGF-beta1 mRNA, while only a small percentage of glomerular macrophages expressed PDGF B-chain mRNA. No PDGF beta-R mRNA expression by macrophages was detected. CONCLUSION: TSLP transgenic mice develop a membranoproliferative glomerulonephritis in which glomerular cell proliferation and matrix deposition are associated with an increased expression of PDGF B-chain, PDGF beta-R and TGF-beta1. These findings extend the paradigms covering these growth factors established in the rat Thy 1 model of mesangiolysis and repairs to a murine model of progressive glomerulonephritis closely resembling human MPGN.     

增加受者体内一氧化碳含量在减轻小鼠移植心缺血再灌注损伤中的作用和机制

目的 观察心脏移植前用二氯甲烷(MC)灌胃增加受者体内一氧化碳含量在减轻小鼠移植心缺血再灌注损伤中的作用及其机制.方法 以Balb/c小鼠作为供、受者,建立颈部异位心脏移植模型.实验共分为4组,分别为MC 100 mg组(n=10)、MC 500 mg组(n=12)、橄榄油组(n=10)和正常对照组(n=5).前3组在麻醉前3 h分别用经橄榄油稀释的MC 100 nag/kg、MC 500mg/kg及单纯橄榄油0.15 ml对受者进行灌胃处理,然后行颈部异位心脏移植;正常对照组小鼠仅作麻醉处理,不进行心脏移植.分别于灌胃后0、1、3、6、12和24 h剪尾采血,测定血液中CO的含量[用碳氧血红蛋白(COHb)占总血红蛋白的百分比表示],并于相应时间点取心肌组织,检测心肌组织中CO的含量;各组移植后3和24 h分别处死半数受者,检测移植后3和24 h血清中肌钙蛋白I(cT-nI)、心肌组织中肿瘤坏死因子α(TNF-α)、白细胞介素10(IL-10)、细胞凋亡与相关基因Bcl-2和Bax mRNA以及核因子κB(NF-κB)的表达,并观察移植心心肌的超微结构.结果 与橄榄油组比较,MC 100 mg和MC 500 mg组受者血液中COHb浓度与心肌组织中CO含量明显升高,均在灌胃后3h达到峰值;MC 100 mg组和MC 500mg组受者心脏移植后3和24h,能显著降低血清中cTnI水平(P<0.01),并以MC 500 mg组降低最为明显;可明显下调促炎症基因TNF-α mRNA水平(P<0.01),而抗炎症基因IL-10 mRNA上调不明显(P>0.05),同时可以显著上调抗凋亡基因Bcl-2 mRNA水平(P<0.01),并抑制促凋亡基因Bax mRNA的转录(P<0.01);心肌超微结构损伤明显减轻.正常对照组可见少量NF-κB表达,而橄榄油组、MC 100 mg组和MC 500 mg组NF-κB活性均显著增强(P<0.01),但后三组之间NF-κB活性的差异无统计学意义(P>0.05).结论 诱导受者体内增加CO含量能通过其抗炎症和抗凋亡功能而减轻移植心缺血再灌注损伤;但与抑制NF-κB信号转导通路无关.     

Anti-HLA antibody binding to hla class I molecules induces proliferation of airway epithelial cells: a potential mechanism for bronchiolitis obliterans syndrome

OBJECTIVE: Development of anti-HLA antibodies is associated with development of bronchiolitis obliterans syndrome after lung transplantation. We sought to determine the mechanism by which anti-HLA antibodies affect the development of bronchiolitis obliterans syndrome. We postulated that anti-HLA antibodies bind to the donor lung epithelium and stimulate phosphorylation and proliferation. METHODS: The A549 lung epithelial carcinoma cell line was cultured in serum-deficient medium to produce static growth. Then the cells were treated with anti-HLA sera from lung transplant recipients, pooled anti-HLA serum from highly sensitized patients, or normal human serum. The cells were also treated with the W6/32 mouse anti-HLA class I monoclonal antibody or control mouse IgG. Tritiated thymidine uptake was determined at 24, 48, and 72 hours. In parallel experiments the cells were treated as described above, and the levels of tyrosine phosphorylation were determined by Western blot analysis. RESULTS: Cells treated with anti-HLA serum or the W6/32 monoclonal antibody exhibited significantly greater proliferation and tyrosine phosphorylation of proteins of approximately 170, 130, 110, and 70 kd compared with cells treated with normal human serum or mouse IgG, respectively. CONCLUSIONS: These data indicate that anti-HLA antibodies have the ability to stimulate airway epithelial cell proliferation and that they may play an important role in the development of bronchiolitis obliterans syndrome. Prevention of HLA sensitization and immunosuppression with agents capable of blocking indirect antigen presentation and the humoral immune response against the allograft may be pivotal in preventing the development of bronchiolitis obliterans syndrome after lung transplantation.