Escherichia coli promotes macrophage apoptosis.

BACKGROUND: Escherichia coli is the bacterium most commonly isolated from the urine of patients with urinary tract infection (UTI). Recurrent episodes of UTI lead to renal interstitial scarring. In interstitial fibrosis and scarring, infiltration of mononuclear cells has been reported to play a key role. MATERIALS AND METHODS: We evaluated the effect of two strains of E. coli--the pathogenic BH-5 and the plasmidless, nonfimbriated HB-101-on human monocyte and murine macrophage apoptosis. RESULTS: E. coli BH-5 enhanced apoptosis in a time- and dose-dependent manner. It also promoted necrosis in a time- and dose-dependent manner. Strain HB-101 promoted monocyte apoptosis in a dose-dependent manner. However, the magnitude of HB-101-induced monocyte apoptosis was lower than BH-5-induced macrophage apoptosis. CONCLUSION: The ability of E. coli to induce apoptosis may contribute to its virulence and play a role in renal interstitial scarring.     

粒细胞巨噬细胞集落刺激因子抑制氟尿嘧啶诱导的胃癌细胞凋亡增强耐药性的实验研究

目的通过检测粒细胞巨噬细胞集落刺激因子（GM-CSF）对氟尿嘧啶（5-FU）诱导后胃癌细胞凋亡的影响,初步探讨GM-CSF参与胃癌细胞耐药性的相关机制。 方法体外培养胃癌SGC7901细胞,MTT法检测5-FU作用于胃癌细胞的半致死剂量;将GM-CSF添加到5-FU处理的胃癌细胞中,MTT法和平板克隆实验检测其对细胞活性和克隆增殖的影响,Annexin V-FITC/PI双染法流式细胞术检测细胞凋亡情况。Western blotting检测凋亡相关蛋白Bax和Bcl-2的表达差异。 结果5-FU对胃癌细胞的半致死剂量为（16±0.4）mg/L。5-FU对胃癌细胞的活性和增殖能力有明显的抑制作用,GM-CSF能有效减弱5-FU的抑制效果（P<0.05）。5-FU能显著诱导胃癌细胞凋亡,Bax/Bcl-2比值显著升高,而加入GM-CSF后,5-FU诱导的凋亡被抵抗,Bax/Bcl-2比值升高趋势被抑制（P<0.05）。 结论GM-CSF能够促进胃癌细胞增殖并有效抑制5-FU诱导的胃癌细胞凋亡,在增强胃癌细胞化疗耐药性方面具有重要作用。     

Association of apoptosis inhibitor of macrophage (AIM) expression with urinary protein and kidney dysfunction

Clinical and Experimental Nephrology - Apoptosis inhibitor of macrophage (AIM) expressed on macrophages prolongs inflammation by protecting macrophages from apoptosis. Most circulating AIM...     

Physiologic levels of resistin induce a shift from proliferation to apoptosis in macrophage and VSMC co-culture

Background

Resistin, an adipokine with inflammatory properties, has been associated with plaque vulnerability. Vascular smooth muscle cells and macrophages are the major cellular components in advanced atherosclerotic plaques and interdependently affect plaque stability. The purpose of this study was to examine the effects of resistin on the interactions of vascular smooth muscle cells and macrophages using co-culture systems.

Morphine-induced macrophage apoptosis modulates migration of macrophages: use of in vitro model of urinary tract infection

BACKGROUND: Morphine has been reported to alter immune function. Morphine-induced macrophage apoptosis has been shown to contribute to altered immune status in an opiate milieu. We studied the effect of morphine-induced macrophage apoptosis on the migration of macrophages. Because urinary tract infection (UTI) is one of the commonest infections to evoke an inflammatory response; i.e., migration of neutrophils and monocytes to the site of infection, we used an in vitro model of UTI to test our hypothesis. MATERIALS AND METHODS: We carried out both in vivo and in vitro studies. Mice of the FVB/N strain were treated with morphine for short (three doses, 24 hours) and long (11 doses, 96 hours) durations, and their bone marrow cells were isolated. In addition, apoptotic macrophages were prepared by heat treatment. To simulate the in vitro model of UTI, E. coli-activated tubular cell (TC)-conditioned medium containing transforming growth factor-beta (TGF-beta) and macrophage-monocyte chemoattractant protein-1 (MCP-1) was used to test migration of macrophages across a filter in a modified Boyden chamber. In addition, migration of macrophages into the peritoneal cavity was evaluated in both control and morphine-treated states. The effect of morphine on apoptosis as well as migration was studied in murine macrophages and bone marrow cells. RESULTS: Morphine not only promoted apoptosis of bone marrow cells (20% apoptotic cells) but also inhibited their migration across the filter. Control cells showed minimal apoptosis but displayed greater migration. Similarly, heat-treated (apoptotic) cells showed minimal migration. In peritoneal macrophage studies, morphine treatment retarded migration. CONCLUSION: Morphine inhibits macrophage migration both in vivo and in vitro. This attenuated transmigration of macrophages seems to be secondary to the apoptotic effect of morphine.     

烟雾吸入性损伤对大鼠肺泡巨噬细胞吞噬功能及炎细胞凋亡的影响

目的 探讨烟雾吸人性损伤对大鼠肺泡巨噬细胞吞噬功能及炎细胞凋亡的影响。方法 选用54只Wistar大鼠，取其中6只作为正常对照组，其余48只制成烟雾吸人伤模型，作为吸人伤组。吸人伤组分别于致伤后2、6、12、24h及2、3、4、5d行支气管肺泡灌洗，获取肺泡巨噬细胞。观察(1)肺泡巨噬细胞体外对鸡红细胞吞噬功能的动态变化；(2)利用髓过氧化物酶(MPO)染色法观察肺泡巨噬细胞的染色阳性率；(3)利用流式细胞仪观察支气管肺泡灌洗液中炎细胞凋亡的动态变化。结果 (1)烟雾吸人伤早期(2～6h)肺泡巨噬细胞吞噬鸡红细胞功能受损，吞噬率下降，12h后逐渐恢复正常。(2)肺泡巨噬细胞MPO染色阳性率在吸人伤后逐渐升高，24h达峰值，2～5d逐渐下降。(3)支气管肺泡灌洗液中细胞凋亡率在3．02％～12．95％之间，以伤后24h凋亡率最高。结论 气管肺泡灌洗液中炎细胞凋亡增加，中性粒细胞凋亡及肺泡巨噬细胞吞噬凋亡细胞参与了烟雾吸人伤大鼠恢复期肺内炎症消散的过程。     

Effect of pamidronate on the stimulation of macrophage TNF-alpha release by ultra-high-molecular-weight polyethylene particles: a role for apoptosis.

The demonstration that one of the mechanisms of action of bisphosphonates (BPs) is the induction of osteoclast and macrophage apoptosis, suggests a potent therapeutic role for the BPs and other apoptosis-modulating agents in the management of periprosthetic osteolysis. The purpose of this study was to improve our understanding of the basic underlying molecular events leading to the inhibitory effect of pamidronate on the macrophage response to ultra-high-molecular-weight polyethylene (UHMWPE) particles. Murine J774 macrophages were incubated for 0-72 h in the presence of UHMWPE particles and/or pamidronate. TNF-alpha release was measured by ELISA while poly(ADP-ribose)polymerase (PARP) expression was measured by Western blot. DNA was analyzed on agarose. The appearance of PARP fragment and the fragmentation of DNA were used as markers of apoptosis. We observed a dose-dependent response to UHMWPE particles with TNF-alpha release reaching 4, 10, and 19 times control with 10, 25, and 125 particles/macrophage, respectively. UHMWPE particles (25 particles/macrophage) stimulate TNF-alpha release by a factor of 10, 7, and 6 after 24, 48, and 72 h, respectively, indicating a rapid stimulating effect of UHMWPE particles on TNF-alpha release. Our results also showed that at 10 particles/macrophage, pamidronate inhibits UHMWPE-induced TNF-alpha release by 12%, 14%, and 23% respectively after 24, 48, and 72 h (p<0.05 vs. 24 and 48 h). With 25 particles/macrophage, the inhibition of TNF-alpha reached 9%, 12%, and 15% after 24, 48, and 72 h (p<0.05 vs. 24 h), respectively. There is no significant difference between the inhibition by pamidronate of TNF-alpha release induced by 125 particles/macrophages at 24, 48, and 72 h. When cells are pre-incubated for 48 h with pamidronate prior to addition of UHMWPE particles for 24 h, we observed an increased inhibition of TNF-alpha compared to the co-incubation protocol. The inhibiting effect of pamidronate reaches 56% when pre-incubated with macrophages prior to incubation with 10 particles of UHMWPE/macrophage (p<0.05 vs. co-incubation).Co-incubation of pamidronate with UHMWPE particles also led to the appearance of the proteolytic PARP fragment after 24 h incubation. We also demonstrated the stimulation of DNA fragmentation (DNA laddering) after 48-72 h with pamidronate. The proteolytic cleavage of PARP, an early event in the induction of apoptosis, precedes the inhibition of UHMWPE particle-induced TNF-alpha release by pamidronate whereas the fragmentation of DNA, a late apoptotic event, parallels this inhibition. Our results suggest the induction of macrophage apoptosis is associated with the inhibitory effect of pamidronate on TNF-alpha release. There is a need for the development of medical management of periprosthetic osteolysis. The demonstration that drugs such as pamidronate induce specific apoptosis-related pathways in macrophages contributes data for a rational approach in the treatment and/or prevention of periprosthetic osteolysis.     

Involvement of peritoneal macrophage in the induction of cytotoxicity due to apoptosis in ascitic fluid associated with severe acute pancreatitis

The aim of this study was to assess the significance of peritoneal macrophage in inducing cytotoxicity in ascitic fluid associated with severe acute pancreatitis. The involvement of peritoneal macrophage was examined experimentally in rats by macrophage depletion with peritoneal lavage prior to the development of pancreatitis. More than 94% of the cellular components collected from peritoneal cavities by the lavage are macrophages. Although the ascitic fluid collected from the rats with necrotizing pancreatitis showed cytocidal effects via apoptosis on Madin-Darby canine kidney cells in a dose- and time-dependent manner, cytotoxicity or apoptosis-inducing activity almost disappeared from the ascitic fluid by the preceding peritoneal lavage. The ascitic fluid did not show significant differences by the lavage in osmolarity and in concentrations of albumin, bilirubin, amylase, and lipase. Although a slight reduction of tumor necrosis factor-alpha was noted with the lavage, tumor necrosis factor-alpha failed to induce apoptotic cell death in the cells, and the neutralization by antibody ameliorated neither cell death nor apoptosis. We conclude that peritoneal macrophages secrete apoptosis-inducing factor(s) into pancreatitis-associated ascitic fluid, other than tumor necrosis factor-alpha.     

Acidification enhances peritoneal macrophage phagocytic activity

BACKGROUND: Laparoscopic surgery is currently used in an array of diverse clinical situations, including cases with potential bacterial contamination. Previous studies have shown that CO2 insufflation during laparoscopic procedures modulates the immune response due to the acidification of the peritoneum. In the present study, we investigated whether exposure of macrophages to an acidic environment, such as that produced by CO2 insufflation, could affect phagocytosis, which is the fundamental process for bacterial clearance. MATERIALS AND METHODS: A murine peritoneal macrophage line (J774) was pre-incubated at pH levels of 6.0 or 7.4 for 3 h at 37 degrees C and returned to neutral pH (7.4). Phagocytosis was evaluated by incubation with fluorescein isothiocyanate-conjugated IgG-opsonized bacterial particles, IgG-opsonized fluorescent latex beads, and non-opsonized fluorescent latex beads at 37 degrees C, pH 7.4. The intensity of the internalized signal was measured by using a fluorometer. RESULTS: Pre-incubation of macrophages at a pH of 6.0 resulted in a significant increase of phagocytic activity of opsonized particles. However, it did not change the uptake of non-opsonized particles. This effect was due to the internalization process since there were no differences in foreign particle binding of cells exposed to acidic or neutral pH levels. CONCLUSIONS: This study demonstrates that environmental acidification increases the phagocytosis of opsonized particles by macrophages. These results suggest that CO2 insufflation during laparoscopic surgery may be beneficial for the clearance of pathogens, particularly in cases where there is a high risk of potential intra-abdominal infections.     

Cytotoxic macrophage in graft-versus-host reaction.

Peritoneal macrophages of F1 hybrid mice injected with parental strain spleen cells 8-14 days previously ("early" graft-versus-host (GVH) macrophages) develop an increased ability to destroy in vitro bystanding target cells of syngeneic, allogeneic, and xenogeneic origin. At later stages of GVH reaction, the nonspecific cytotoxicity of macrophages wanes ("late" GVH macrophages) and does not differ much from that of control macrophages. Trypsinization of early GVH macrophages or iodoacetate treatment significantly reduces their cytotoxicity, whereas anti-theta serum and complement have only a moderate effect. Antimouse IgM antibody significantly enhanced the cytotoxic potential of early GVH macrophages, but had no effect either on normal or late GVH macrophages. In contrast, antimouse IgG antibody enhanced, although slightly, only the cytotoxic activity of late GVH macrophages. Two possible explanations of the increased cytotoxicity of early GVH macrophages are offered: (1) cytophilic antibody of IgM type, directed against host antigens, renders macrophages capable of damaging nonspecifically bystanding target cells upon contact with antigen; (2) IgM alloantibody produced by parental cells changes the surface properties of macrophages and contributes to the cytotoxicity of these cells.     

巨噬细胞及粒巨细胞-集落刺激因子对大鼠腹壁皮瓣成活的影响

目的 研究巨噬细胞及粒巨细胞-集落刺激因子(GM-CSF)对大鼠腹壁动脉穿支(deep epigastric perforator,DEP)皮瓣模型的影响.方法 建立SD大鼠DEP皮瓣模型,分别给予大鼠GM-CSF(Ⅰ组)、腹腔巨噬细胞(Ⅱ组)、GM-CSF联合巨噬细胞(Ⅲ组)及乍理盐水(Ⅳ组).术后第7天取皮瓣检测成活而积、组织学观察、微血管密度(MVD)、皮瓣内胶原含量.结果 皮瓣成活率Ⅰ组(53.08%±8.76%)和Ⅱ组(47.95%±4.92%)间无差异,均高于Ⅳ组(43.28%±5.27%)而低于Ⅲ组(61.68%±6.60%),P<0.05.皮瓣MVD Ⅰ组(24.82±4.18)和Ⅱ组(24.30±3.02)间差异无统计学意义,均显著高于Ⅳ组(21.37±2.65),低于Ⅲ组(29.82±4.74).胶原含量Ⅰ组(17.25%±2.85%)高于Ⅳ组(14.41%±2.89%),P<0.05.Ⅱ组(12.69%±3.55%)稍低于Ⅳ组.Ⅲ组(20.31%±3.01%)较Ⅰ组显著增高,P<0.05.结论 重组大鼠GM-CSF和巨噬细胞均能够促进大鼠DEP皮瓣成活,联合应用可发挥协同作用促进皮瓣存活、血管生成以及胶原沉积.     

Alveolar macrophage dysfunction in malignant lung tumours

Alveolar macrophage chemotaxis was measured in 129 individuals--13 normal volunteers, 15 tumour free patients with recent bronchopulmonary infections, 10 patients with chronic bronchitis, 29 patients with endothoracic sarcoidosis, 48 patients with primary bronchial carcinoma and 14 patients with pulmonary metastases from various origins. Chemotaxis was tested in the presence of either zymosan activated autologous serum, N-formyl-methionine-leucyl-phenylalanine (F-Met-Leu-Phe), or zymosan activated human AB serum. Alveolar macrophage chemotaxis was significantly less in patients with bronchial carcinoma than in healthy volunteers (p less than 0.01). Chemotaxis was significantly more depressed in samples obtained from the neighbourhood of the tumour than in samples from the opposite lung. Defective chemotaxis was also found in patients with sarcoidosis. In contrast, the presence of lung metastases did not affect chemotaxis. A recent bronchopulmonary infection was associated with significantly increased (p less than 0.02) chemotaxis in tumour free patients but not in patients with a primary lung tumour. The findings suggest that an intrinsic functional defect of alveolar macrophages might favour the development of bronchogenic carcinoma.