Expression and activation of 15-lipoxygenase pathway in severe asthma: relationship to eosinophilic phenotype and collagen deposition

BACKGROUND: Although 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), a product of 15-lipoxygenase (15-LO), may be involved in mild to moderate asthma, little is known about its potential roles in severe asthma. OBJECTIVES: This study was performed to evaluate 15(S)-HETE levels in bronchoalveolar lavage fluid (BALF) from severe asthmatics with and without airway eosinophils and from the control groups. In addition, 15-LO protein expression was examined in endobronchial biopsy, while its expression and activation were evaluated in BAL cells. RESULTS: While 15(S)-HETE levels in BALF were significantly higher in all severe asthmatics than normal subjects, severe asthmatics with airway eosinophils had the highest levels compared with mild, moderate asthmatics and normal subjects. 15(S)-HETE levels were associated with tissue eosinophil numbers, sub-basement membrane thickness and BALF tissue inhibitor of metalloproteinase-1 levels, and were accompanied by increased 15-LO expression in bronchial epithelium. In addition, activation of 15-LO was suggested by the increased proportion of 15-LO in the cytoplasmic membrane of alveolar macrophages from severe asthmatics. CONCLUSION: The data suggest that severe asthmatics with persistent airway eosinophils manifest high levels of 15(S)-HETE in BALF, which may be associated with airway fibrosis. It is likely that 15-LO expression and activation by airway cells explain the increased 15(S)-HETE levels.     

C4d Deposition and Clearance in Cardiac Transplants Correlates With Alloantibody Levels and Rejection in Rats

Antibody-mediated rejection of human cardiac transplants is correlated with C4d deposits and macrophage infiltrates in capillaries of endomyocardial biopsies. We produced an antibody to rat C4d to study C4d deposition and clearance in Lewis rats that were sensitized with a blood transfusion from DA rats 7, 14 or 21 days before cardiac transplantation. Cyclosporin A (CsA) immunosuppression was initiated after transplantation at a dose that inhibited graft rejection, antibody production and C4d deposition in unsensitized recipients. Blood transfusion elicited high levels of circulating IgG alloantibodies, predominantly of the complement-activating IgG2b subclass, that peaked 14 days after transplantation. At this time, macrophages accumulated in capillaries, and C4d deposits were diffuse and intense on arteries, capillaries and veins. Grafts that survived 90 days in sensitized recipients still had deposits of C4d that were associated with increased interstitial fibrosis and vasculopathy in arteries. Clearance of C4d was determined by retransplanting DA cardiac allografts from Lewis recipients back to DA recipients. C4d deposits were decreased to minimal levels within 5 days after retransplantation. Thus, C4d deposition is not limited to the capillaries, but extends throughout the arterial tree, and despite formation of a covalent bond, C4d is cleared within days.     

Axotomy of the rat facial nerve leads to increased CR3 complement receptor expression by activated microglial cells

Axotomy of the rat facial nerve leads to mitotic divisions of microglial cells without developing into phagocytes. In order to study the functional characteristics of those activated, i.e., proliferating but nonphagocytic, microglia we investigated the expression of monocyte/macrophage antigens by these cells. Our results show that activated microglia lack monocyte/macrophage antigens recognized by the monoclonal antibodies Ox-41, ED1, ED2, and Ki-M2R but express high levels of CR3 complement receptors in situ.     

Nonbronchoscopic approach to bronchoalveolar lavage in children with artificial airways.

Bronchoalveolar lavage (BAL) performed with a fiberoptic bronchoscope (FOB) is a useful method for sampling alveolar contents. Since the smallest FOB with a channel has a diameter of 3.6 mm, BAL is difficult to accomplish through artificial airways (AA) less than 5.0 mm I.D. We used a 4F balloon wedge pressure catheter to perform BAL through small AA. Supplemental O2 or ventilatory support was delivered via an adaptor through which the catheter was introduced. After it was passed distal to the AA, the balloon was inflated with normal saline (NS) to a predetermined volume, and advanced until resistance was felt. The balloon was deflated, advanced slightly, and then reinflated to achieve airway occlusion. Five aliquots of 0.75 mL/kg of NS were used for BAL. The procedure was performed in 20 children from 1 month (950 g) to 6 1/2 years of age (median, 9 months). All specimens contained abundant alveolar macrophages, indicating good recovery of alveolar contents. Clinically significant information was obtained in 17 (85%) cases, and no patient required an open lung biopsy. In conclusion, nonbronchoscopic bronchoalveolar lavage is a valuable method for obtaining alveolar contents in children with small AA that preclude the use of an FOB, and it obviates the need for open lung biopsy in many patients. This technique could be used as a research tool for measuring constituents of alveolar contents in infants and small animals.     

Macrophage-like cells from explant cultures of rat sciatic nerve produce apolipoprotein E

Apolipoprotein E is synthesized and secreted by degenerating peripheral nerve, but the role of resident endoneurial cells in this process is not clear. To exclude the involvement of nonresident cells, we examined the cellular source of endoneurial apolipoprotein E in explant cultures of rat sciatic nerve. The cellular outgrowth from these explant cultures released apolipoprotein E into the culture medium. The cellular outgrowth contained fibroblasts, Schwann cells, and a population of cells with many phenotypic characteristics of macrophages, including the production of apolipoprotein E. No other cell type in the cultures appeared to contribute to this production. These data suggest that apolipoprotein E is produced by resident endoneurial cells in explant cultures and that these cells are macrophages.     

欧芹素乙和异欧芹素乙对小鼠腹腔巨噬细胞体外释放肿瘤坏死因子的抑制作用

研究了欧芹素乙（Ｉｍｐｅｒａｔｏｒｉｎ，Ｉｍｐ）和异欧芹素乙（Ｉｓｏ－ｉｍｐｅｒａｔｏｒｉｎ，Ｉｓｉ）及对照药物维拉帕米（Ｖｅｒａｐａｍｉｌ，Ｖｅｒ）对小鼠腹腔巨噬细胞体外释放肿瘤坏死因子（Ｔｕｍｏｒｎｅｃｒｏｓｉｓｆａｃｔｏｒ，ＴＮＦ）的影响。结果表明：Ｉｍｐ、Ｉｓｉ及Ｖｅｒ对小鼠腹腔巨噬细胞体外释放ＴＮＦ具有显著的抑制作用。药物浓度在１０－６～１０－４ｍｏｌ／Ｌ范围内，该抑制作用呈剂量依赖性：药物浓度达１０－４ｍｏｌ／Ｌ时，则可完全抑制ＴＮＦ的释放。     

杂多阴离子对SiO_2细胞毒性的拮抗作用

本文采用离体细胞培养法,以细胞存活率、乳酸脱氢酶活性和酸性磷酸酶活性为指标,研究了几种α-Keggin结构的杂多阴离子对石英粉尘细胞毒性的影响。结果表明,与对照组比较,所用杂多阴离子无细胞毒性(P>0.05),石英尘经杂多阴离子作用后,细胞毒性显著降低,与石英尘组比较,上述三项指标差异均有显著意义(P<0.01),由此表明杂多阴离子对石英的细胞毒性有明显的拮抗作用。     

Surface coat of sheep pulmonary intravascular macrophages: Reconstitution,and implication of a glycosyl-phosphatidylinositol anchor

Background: Pulmonary intravascular macrophages (PIMs) of sheep have a globular surface coat that facilitates endocytosis of tracer particles and Escherichia coli lipopolysaccharide, and is disrupted by the heparin and Brefeldin A treatments. The present study investigated the in vivo dynamics of the coat globules following heparin-mediated removal, and the mechanism of globule organization on the plasma membrane of PIMs in vitro. Methods: Sheep were administered heparin at a dose of 50 IU/kg body weight IV, and euthanised at 30 min, 3, 6, 12, 48, and 120 hr (n = 2 for each treatment) after the treatment. Control sheep (n = 2) were injected with normal saline solution. The tissues were processed for an ultrastructural examination and acid phosphatase (ACPase) cytochemistry. Heparintreated lungs were subjected to morphometric analysis of the coat globules. Lung tissues from normal sheep (n = 2) were incubated with phosphatidylinositol-specific-phospholipase C (PIPLC; 2 IU/ml PBS) in vitro for 30 and 75 min. Results: Heparin study: The ultrastructural and morphometric data showed that the coat globules were removed at 30 min and reconstituted within 48 hr of the treatment. The PIMs showed priminent Golgi complexes associated with secretory vesicles, microtubules, and centriole between 3–12 hr of heparin treatment. Acid phosphatase cytochemistry also demonstrated secretory activity in the Golgi complexes of PIMs during the coat reconstitution. PIPLC study: The coat globules of PIMs were removed in a time-dependent mode by the PIPLC treatment without damage to other cell organelles. Conclusions: This study demonstrates a time-dependent reconstitution of the coat of PIMs in conjunction with secretory activity following heparinmediated removal, probably through sequenstration of the globules from blood. This ability is of functional significance as the coat mediates particle endocytosis by the PIMs. The results also suggest the presence of a glycosyl-phosphatidylinositol (GPI) anchor in tethering of globules on the plasma membrane of PIMs to offer a structural basis for their integrity in pulmonary vascular flow. © 1995 Wiley-Liss, Inc.     

营养缺乏及补充维生素A对大鼠肺巨噬细胞功能的影响

采用Ｗｉｓｔａｒ大鼠，从怀孕１６天进行限食喂养直到生后４５天，干预组从生后第３６天及第４２天分别给予维生素Ａ灌胃，每次２０００ＩＵ。结果表明，补充维生素Ａ可明显增加大鼠的胸腺重量、肺巨噬细胞的数目、巨噬细胞的吞噬功能及ＮＯ－２的分泌。维生素Ａ可部分纠正营养缺乏导致的免疫缺陷、胸腺萎缩，活化肺巨噬细胞功能，其作用机制有待于进一步研究。