转化生长因子-β在哮喘气道重构中的作用研究进展

转化生长因子-β(TGF-β)是一个结构相关的生长因子大家族的一员,具有广泛调节细胞增殖、分化和凋亡等生物学功能。肺组织中多种细胞如肺泡巨噬细胞和肺纤维原细胞、上皮细胞、内皮细胞和平滑肌细胞均可合成TGF-β。发作期哮喘患者支气管肺泡灌洗液中以及在中度和重度哮喘患者气道黏膜活检标本中,TGF-β为过度表达。TGF-β可加重气道上皮的损害,刺激成纤维细胞、气道平滑肌细胞增殖,通过促进细胞外基质的合成、诱导结缔组织生长因子表达而导致气道上皮下纤维化,在哮喘的气道重构中具有重要的功能,因此针对TGF-β治疗成为防治哮喘气道重构新的研究方向。     

吸烟在肺衰老中的作用

肺衰老是由机体衰老进程(年龄增长)和(或)内外有害环境作用所引起的肺部衰老性变化。吸烟可通过端粒缩短、线粒体功能障碍、蛋白稳态失衡、表观遗传改变、DNA损伤修复异常和细胞外微环境失调等病理改变促进肺衰老, 并参与多种慢性呼吸系统疾病的发生发展。本文从气道上皮、肺泡上皮、血管内皮、成纤维细胞和免疫细胞角度, 对吸烟在肺衰老中的作用进行总结。     

气道上皮屏障功能异常在支气管哮喘发病中的作用

支气管哮喘(哮喘)的主要表现为咳嗽、咳痰、胸闷和喘息,这些症状的病理生理学基础是气道高反应性和气道慢性嗜酸粒细胞炎症。气道上皮细胞是呼吸道的第一道防线,环境因素和炎症作用的影响引起气道上皮反复损伤、修复和再生导致气道黏膜上皮的组织学改变和功能异常。气道上皮的屏障功能与气道上皮细胞因子胸腺基质淋巴细胞生成素,白细胞介素25和白细胞介素33密切相关,哮喘患者气道上皮屏障的损害增强了气道上皮黏膜对异物的通透性,引起气道上皮细胞、树突状细胞和先天性固有淋巴样细胞(ILC2s)的激活。气道上皮细胞的功能异常以及树突状细胞、Th2细胞和ILC2s的激活形成一个免疫病理单元,引起过敏性气道炎症,在哮喘的发病中发挥重要作用。     

慢性支气管炎和肺气肿中的肺内分泌细胞

目前,肺内分泌细胞与疾病的关系越来越受到人们的重视。本文简介正常肺内分泌细胞和支气管炎与肺气肿患者的肺内分泌细胞改变。 Cutz E等曾应用PAP法对正常肺内分泌细胞进行了研究。他们发现肺内分泌细胞中,无论是孤立细胞还是神经上皮小体(N-EBs),均含有5-羟色胺、蛙皮素和降钙素;仅孤立细胞含亮氨酸—脑啡肽。各年龄组中均测出蛙皮素、降钙素和亮氨酸—脑啡肽。含蛙皮素的细胞数目最多,含降钙素的细胞较少,含亮氨酸—脑啡肽的细胞极少。含蛙皮素的细胞散在分布于气道上皮,胎儿肺中见于各级支气管树,而在生后及成人肺组织     

气道上皮与支气管哮喘

本着重介绍了气道上皮的细胞组成、结构以及上皮的粘附机制；气道上皮细胞作为哮喘炎性介质等作用的靶细胞及其在气道高反应性中的作用；气道上皮作为效应细胞在哮喘发病过程的作用。     

气道上皮与支气管哮喘

本文着重介绍了气道上皮的细胞组成、结构以及上皮的粘附机制;气道上皮细胞作为哮喘炎性介质等作用的靶细胞及其在气道高反应性中的作用;气道上皮作为效应细胞在哮喘发病过程的作用。     

呼吸道上皮在移植后闭塞性细支气管炎中的作用研究进展

肺移植术后移植物的长期存活受限于闭塞性细支气管炎（obliterative bronchiolitis,OB）的出现。近年来研究发现,呼吸道上皮是OB发生的始发和核心环节。上皮损伤后启动机体的体液和细胞免疫,失去对成纤维细胞的抑制,促进OB的发生。减轻气道上皮的损伤可以减轻OB的程度。转换气道上皮的表型可以使移植物获得长期的免疫耐受,为临床上OB的治疗提供新的方法。     

先天免疫与COPD

2001年发表的“慢性阻塞性肺疾病全(COPD)球防治创议(GOLD)”和2002年我国发表的“慢性阻塞性肺疾病诊治指南”为COPD制定了新的定义,认为COPD是一种以气流受限为特征的疾病,气流受限通常呈进行性发展,不完全可逆,多与肺部对有害颗粒或有害气体的异常炎症反应有关。该定义突出了不完全可逆的气流受限和气道的炎症特征,当各种有害颗粒或气体进入气道后,首先引发气道上皮的防御反应,导致多种炎症细胞的集聚活化,并通过自分泌和旁分泌方式释放各种炎性介质,作用于各种气道结构细胞,包括上皮细胞、平滑肌细胞、基质细胞等,发生气道重构,…     

微血管通透性在哮喘发病机理中的作用

哮喘时,是炎性细胞还是介质起主要作用,尚有争议,但是介质作用于特异的肺靶组织已得到公认。靶组织中除了气道平滑肌、气道上皮、腺体和传入(可能还有传出)神经外,也应该包括气道的微血管系,特别是毛细血管后小静脉的炎性变化引入注目,在介质作用下小静脉的内皮细胞间形成间隙,大量血浆蛋白渗出到间质内,产生粘膜和粘膜下水肿。渗出物进入气道腔内,粘附在上皮层上,影响纤毛上皮层的功能。【微血管通透性与粘膜上皮通透性不同】哮喘病人气道粘膜上皮对各种吸入性刺激物通透性     

支气管哮喘小气道炎症及结构变化

通过对哮喘患者的尸检和活体组织检查,发现哮喘患者的气道有炎症浸润和结构改变。但在这些研究中都注意的是大气道的变化。哮喘患者小气道的病理变化是否与大气道相同,炎症反应是否导致小气道的结构改变。是人们极为关注的问题。 炎症细胞:研究观察了大、小气道的炎症细胞数量,通常把直径小于2mm的气道定义为小气道。Synek等对死于哮喘的患者,与患有哮喘但死于其他原因的患者的气道上皮及支气管壁中的白细胞数量进行了比较。结果表明,嗜酸粒细胞在支气管上皮的浸润遍及大小气道。急性重症哮喘患者近端气道浸润严重。在一组死于急性、窒息性哮喘的5例患者中有同样发现。其T细胞、嗜酸粒细胞和巨噬细胞的数量在近端气道高于直径小于1mm的气道。对切除的肺组织     

中性粒细胞弹性蛋白酶及其抑制剂与肺癌关系的研究进展

肿瘤转移作为一系列复杂事件的结果,这一过程需要很多酶的参与.中性粒细胞弹性蛋白酶在肺癌侵袭和转移中发挥重要作用,在生理条件下,中性粒细胞弹性蛋白酶有很多特殊的作用底物,过量的中性粒细胞弹性蛋白酶可导致弹力蛋白的降解,还可导致细胞外基质的降解.肺癌组织中的中性粒细胞弹性蛋白酶的量不仅可作为肺癌预后的独立指标,而且在重度联合免疫缺陷小鼠的肺癌种植模型中,一种特殊的中性粒细胞弹性蛋白酶抑制剂ONO-5046完全抑制了肺癌细胞的生长.中性粒细胞弹性蛋白酶免疫抑制剂的应用有望成为阻止肺癌侵袭和转移的有效方法.     

Hemoperfusion with an immobilized polymyxin B column reduces the blood level of neutrophil elastase

BACKGROUND: We investigated whether direct hemoperfusion with an immobilized polymyxin B column (DHP with PMX) could reduce the blood level of neutrophil elastase. METHODS: 20 sepsis patients were enrolled in the study. DHP with PMX was performed twice within a 24-hour period. Neutrophil elastase was measured 7 times. RESULTS: Neutrophil elastase was 468 +/- 75.1 microg/l, while it was 1,531 +/- 201.7 microg/l immediately after the first session, declined to 351 +/- 73.9 microg/l before the second session of DHP with PMX, and increased again to 599.3 +/- 112.7 microg/l immediately after the second session, 328 +/- 73.7 microg/l at 24 h, 264 +/- 39.3 microg/l at 48 h, and 230 +/- 36.1 microg/l at 72 h after DHP with PMX. The levels from 48 h onwards were significantly lower compared with that before treatment. CONCLUSION: DHP with PMX has an overall effect that reduces circulating neutrophil elastase levels.     

Gut luminal neutrophil migration is influenced by the anatomical site of Crohn's disease

BACKGROUND: Clinical differences between small- and large-bowel Crohn's disease have been demonstrated. Neutrophil migration and degranulation are important effector mechanisms in gut damage. Granulocyte elastase, a neutrophil-bound enzyme, interleukin 8 and 1beta can be detected in whole-gut lavage fluid. We aimed to assess differences between large- and small-bowel Crohn's disease. METHODS: A total of 167 patients with active inflammatory bowel disease (118 Crohn's disease, 49 ulcerative colitis) underwent whole-gut lavage with a polyethylene glycol electrolyte solution. Granulocyte elastase was assayed using an enzyme substrate reaction, IL-8 and IL-1beta by ELISA. RESULTS: Twenty-seven of 36 patients with isolated colonic Crohn's disease had detectable granulocyte elastase (median 0.259 pKat/l, range < 0.039-2.742 microKat/l), whereas 3 of 15 with small-bowel involvement alone had detectable granulocyte elastase (median < 0.039 microKat/l, range < 0.039-0.266 microKat/l; P < 0.0001). Granulocyte elastase levels were significantly higher in patients with ileocolonic disease and post-ileocaecal resection compared with small-bowel disease alone. IL-8 (P< 0.0001) and IL-1beta (P < 0.04) levels differed between colonic and ileal distributions. No variations were seen in ulcerative colitis. CONCLUSIONS: Neutrophil migration to the gut lumen in Crohn's disease is a feature of colonic disease irrespective of associated ileal lesions. This suggests that bacterial-derived chemo-attractants may play a role. High levels of IL-8 in colonic disease are consistent with this hypothesis.     

Activated Neutrophils Impair Gastric Cytoprotection: Role of Neutrophil Elastase

Neutrophil elastase decreases production of PGI₂ by cultured endothelial cells. Thus, neutrophil elastase may play an important role in gastric mucosal injury by decreasing the tissue level of PGI₂, an important gastric cytoprotective substance. We examined whether activated neutrophils inhibit gastric PGI₂ production in rats subjected to water-immersion restraint stress. Gastric 6-keto-PGF₁ levels were determined by enzyme immunoassay. Gastric mucosal blood flow was determined by laser–Doppler flowmeter. Gastric microvascular permeability was determined by Evans blue leakage. Gastric levels of 6-keto-PGF₁ were transiently increased 0.5 hr after the stress, followed by a decrease to below baseline at 6 hr, when mucosal blood flow fell to 60% of baseline. Gastric levels of 6-keto-PGF₁ were significantly higher in animals with nitrogen mustard-induced leukocytopenia than in controls 1 and 6 hr after the stress. In leukocytopenic animals, levels 6 hr after stress were not lower than those preceding stress. Leukocytopenia markedly limited both the decrease in mucosal blood flow and the increase in gastric microvascular permeability. The level of gastric mucosal injury observed 6 hr after the stress was markedly attenuated by leukocytopenia. Pretreatment with neutrophil elastase inhibitors (ONO-5046 and Eglin C) or an anti-P-selectin monoclonal antibody produced effects similar to leukocytopenia. Neutrophil elastase is involved in the stress-induced gastric mucosal injury by decreasing gastric production of PGI₂. Thus, pharmacologic inhibition of neutrophil elastase should help to prevent stress-induced gastric mucosal injury.     

Expression of neutrophil elastase and myeloperoxidase mRNA in patients with newly diagnosed type 2 diabetes mellitus

Background and aimsNeutrophil elastase and myeloperoxidase enzymes protect us from infection by killing pathogens. However, exaggerated activities of these enzymes can induce tissue damage, inflammation and oxidative stress. The present study was aimed to explore the expressions of neutrophil elastase and myeloperoxidase mRNA in the peripheral blood leukocytes (PBL) in patients with newly diagnosed type 2 diabetes mellitus.MethodsIn this cross-sectional study, 104 participants including 65 normoglycemic control subjects and 39 newly diagnosed type 2 diabetes patients were recruited. Glycemic and metabolic markers were evaluated from fasting blood samples. The mRNA levels of neutrophil elastase and myeloperoxidase genes in the PBL were quantified by real-time quantitative PCR.ResultsCompared to control subjects, diabetes patients showed a significant down regulation of both neutrophil elastase (p = 0.039) and myeloperoxidase (p = 0.023) mRNA expressions in the PBL. The neutrophil elastase and myeloperoxidase mRNA levels showed a negative trend with fasting glucose levels but did not show any significant correlations with HbA1c, insulin level, insulin resistance or sensitivity status.ConclusionsIt was concluded that type 2 diabetes mellitus is associated with a decrease in neutrophil elastase and myeloperoxidase gene expression in the PBL.     

The contribution of leukocyte proteases to fibrinolysis

Summary Polymorphonuclear leukocytes accumulate within blood clots and may contribute to fibrinolysis. The primary fibrinolytic enzymes of neutrophils are cathepsin G and elastase. Fibrin can be exposed to these granular enzymes as a result of cell lysis, phagocytosis of fibrin, or secretion of the enzymes from the cells. Neutrophil secretion occurs in association with blood coagulation and is dependent upon a plasma factor(s) and calcium. After secretion, the enzymes can degrade fibirn within a plasma environment. This is demonstrated by the inhibition of fibrinolysis by specific inhibitors of elastase and the augmentation of fibrinolysis by neutralization of the primary plasma inhibitor of elastase, ₁-proteinase inhibitor. A radioimmunoassay which discriminates elastase from plasmic degradation products of fibrinogen has been developed. In this assay, elastase elicited degradation products of fibrin(ogen) were detected in certain pathophysiologic plasma samples. Taken together, these findings indicate a role for leukocyte proteases in physiological fibrinolysis.Abbreviations PMN polymorphonuclear leukocytes - PK prekallikrein - FDP fibrin(ogen) degradation products This work was supported by HL 17 964 from the National Heart, Lung and Blood Institute     

Destruction of articular cartilage by alpha2 macroglobulin elastase complexes: role in rheumatoid arthritis

OBJECTIVE: Neutrophil elastase accounts for the ability of some fresh rheumatoid synovial fluids to degrade cartilage matrix in vitro. The aim of this study was to determine if enzyme activity could result from depletion of synovial fluid inhibitors or protection of the enzyme from inhibition. METHODS: The ability of synovial fluids to inhibit porcine pancreatic elastase was investigated together with chemical pretreatments capable of inactivating alpha 1 protease inhibitor (alpha 1PI) or preventing formation of alpha 2 macroglobulin (alpha 2M) elastase complexes. Subsequently, complexes of human neutrophil elastase with alpha 2M were prepared and applied to frozen sections of cartilage. Proteoglycan loss was quantified by alcian blue staining and scanning and integrating microdensitometry. Parallel studies were carried out using a low molecular weight chromogenic elastase substrate. The effects of alpha 1PI and SF on these systems were investigated. Finally, synovial fluids were subjected to gel filtration and the fractions assayed for elastase activity. High molecular weight fractions were pooled, concentrated, and tested for their ability to degrade cartilage sections. RESULTS: All synovial fluids reduced the activity of porcine pancreatic elastase, the inhibition mainly being attributable to alpha 1PI, whereas remaining activity resulted from complexes of elastase with alpha 2M. Complexes of human neutrophil elastase with alpha 2M were shown to cause proteoglycan degradation in frozen sections of human articular cartilage. Alpha 1PI prevented alpha 2M elastase complexes from degrading cartilage but not the chromogenic substrate. The data suggested that alpha 1PI does not inhibit elastase bound to alpha 2M but sterically hinders the complex. However, only one of five synovial fluids was able to completely block the actions of alpha 2M elastase complexes against cartilage. Gel filtration of rheumatoid synovial fluids showed elastase and cartilage degrading activity to be associated with fractions that contained alpha 2M, and not with fractions expected to contain free enzyme. CONCLUSIONS: The data suggest that synovial fluid alpha 2M elastase complexes can degrade cartilage matrix in rheumatoid arthritis.     

Neutrophil-elastase in chronic inflammatory bowel disease: a marker of disease activity?

BACKGROUND/AIMS: Neutrophil elastase is a proteinase which exists in granulocytes and plays an important role in the pathogenesis of inflammatory disorders. In inflammatory bowel disease there is a leukocyte infiltration of the bowel mucosa. The purpose of this study was to examine whether plasma elastase represents a reliable laboratory marker for establishing the activity of chronic inflammatory bowel disease. METHODOLOGY: We measured plasma elastase concentrations in 61 patients suffering from either Crohn's disease or ulcerative colitis and compared these data with other clinical and laboratory findings and with elastase concentrations in 40 healthy controls. The sensitivity and specificity of the elastase values in chronic IBD were calculated with the use of concomitant measurements of CRP and ESR. RESULTS: Plasma levels were found to be significantly higher in patients (49 micrograms/l) compared with healthy controls (23 micrograms/l). Patients with active disease had higher plasma levels than patients in remission. In general, the sensitivity of elastase to detect active inflammatory bowel disease was about 60%; the specificity was 65%. For patients in remission, the sensitivity was higher than 80%. However, there was a wide range of overlapping values between chronic inactive patients and those with moderately active disease. CONCLUSIONS: We conclude that plasma elastase is a useful independent marker of disease activity in inflammatory bowel disease. Especially for identifying patients in remission, the measurements of elastase seem to be more suitable than other parameters of inflammation, like CRP or ESR.     

Neutrophil elastase-releasing factors in bronchoalveolar lavage from patients with adult respiratory distress syndrome

Bronchoalveolar lavage fluid (BAL) was obtained from patients with adult respiratory distress syndrome (ARDS). Controls included BAL from normal subjects and from patients with sarcoidosis or pulmonary fibrosis. Neutrophil elastase measured immunologically was found in all BAL samples, but it was strikingly greater in BAL from patients with ARDS than in the BAL from normal subjects or patients with sarcoidosis. There was no significant difference in the neutrophil elastase antigen concentrations in BAL samples from patients with ARDS and those with pulmonary fibrosis. No elastolytic activity was found in either group. The alpha-1-antitrypsin and the bronchial mucus inhibitor were greater in BAL from patients with ARDS. There was a highly significant correlation between the alveolar-arterial oxygen tension difference and the neutrophil elastase concentration in BAL from the patients with ARDS. Kallikrein, prekallikrein, factor XIa-like activity, and high molecular weight kininogen antigen were found in BAL of patients with ARDS, suggesting that the kallikrein-kinin cascade may be activated in the lungs of patients with ARDS. Kallikrein-like activity in the BAL from the patients with ARDS was significantly correlated with the number of neutrophils in the BAL, the neutrophil elastase concentration, and the ability of the BAL to release elastase from cytochalasin-B-treated neutrophils. There was no correlation between these variables and C5a concentration. These studies demonstrated an association between BAL neutrophil elastase and the clinical state of patients with ARDS.