Asbestos fibres and man made mineral fibres: induction and release of tumour necrosis factor-alpha from rat alveolar macrophages

OBJECTIVES: Mounting evidence suggests that asbestos fibres can stimulate alveolar macrophages to generate the potent inflammatory and fibrogenic mediator, tumour necrosis factor-alpha (TNF-alpha), and that this may play an important part in the onset and development of airway inflammation and lung fibrosis due to asbestos fibre inhalation. Little is known, however, about the ability of other mineral fibres to initiate formation and release of TNF-alpha by alveolar macrophages. Therefore the effects of different fibres (crocidolite, chrysotile A, chrysotile B, two man made mineral fibres (MMVF 21 and MMVF 22), a ceramic fibre (RCF 1), and a silicon carbide whisker fibre (SiCwh)) on formation and release of TNF-alpha by rat alveolar macrophages were examined. METHODS: Cells were isolated and incubated at 37 degrees C with the different fibres, or with culture medium alone (controls), and the amounts of TNF-alpha messenger RNA (mRNA) in the cells and TNF-alpha bioactivity released into the culture medium were measured at different time points. RESULTS: Significantly (P < 0.05 v control) increased amounts of TNF-alpha mRNA were found in cells exposed to crocidolite, chrysotile A, chrysotile B, MMVF 21, RCF 1, or SiCwh for 90 minutes, and significantly (P < 0.05 v control) increased activities of TNF-alpha were found in the medium of macrophages exposed to crocidolite, chrysotile A, chrysotile B, or MMVF 21 for four hours. CONCLUSION: These observations suggest that not only natural mineral fibres but also certain man made mineral fibres are able to induce the formation and release of TNF-alpha by alveolar macrophages in vitro.     

Cotton smoke inhalation primes alveolar macrophages for tumor necrosis factor-alpha production and suppresses macrophage antimicrobial activities

The present study determined the effects of cotton smoke inhalation on the functioning of alveolar macrophages (mphi). Smoke inhalation led to dose-dependent impairment of respiratory gas exchange by 48 h postexposure and pulmonary edema by 96 h. Maximal effects were observed in animals ventilated with 54 breaths of cotton smoke (3-min exposure, 18 breaths/min). Macrophages were obtained at 48 h postexposure by bronchoalveolar lavage of rabbits subjected to 54 breaths of smoke or room air (control). Phagocytosis of opsonized bacteria and adherence to solid substratum were reduced in smoke-exposed mphi. Smoke inhalation primed mphi for release of tumor necrosis factor-alpha (TNF-alpha) induced by lipopolysaccharide (LPS). Smoke-exposed mphi were also primed for TNF-alpha release induced by phorbol myristate acetate, which suggests that the priming event occurred downstream of protein kinase C activation in the signal transduction pathway. Further, smoke exposure attenuated the inhibitory effects of phosphodiesterase inhibitors on LPS-induced TNF-alpha release. Thus, the priming event may be mediated through cAMP and/or protein kinase A. The data indicate that cotton smoke inhalation suppresses the antimicrobial activities of alveolar mphi and can lead to excessive mphi production of TNF-alpha. These mphi effects would be expected to contribute to the pathophysiological abnormalities associated with smoke inhalation injury.     

The effect of antimicrobial agents on the induction of tumour necrosis factor by alveolar macrophages in vitro in response to endotoxin

1. In the present study, we evaluated the role of repeated administration on conditioning place preference (CPP) induced by fencamfamine (FCF) in male rats. 2. Repeated FCF (3.5 mg/kg) or saline once or daily for ten consecutive days enhanced sniffing duration and decreased locomotion and rearing duration. 3. At the 3.5 mg/kg dose, FCF produced a significant place-preference effect. 4. Repeated exposures to FCF intensified its reinforcing properties. 5. These results suggest that repeated FCF administration sensitizes its rewarding effects, as with other addictive substances.     

Amiodarone-induced pulmonary toxicity in Fischer rats: release of tumor necrosis factor alpha and transforming growth factor beta by pulmonary alveolar macrophages

Amiodarone is an antiarrhythmic drug with numerous side effects, the most serious being the development of pulmonary toxicity. We have previously reported that a single intratracheal instillation of amiodarone to Fischer 344 rats results in pulmonary fibrosis within 6 wk of treatment. Presently, the mechanism of amiodarone-induced pulmonary toxicity is unknown. Cytokines that stimulate fibroblast proliferation and/or collagen production may play a role in amiodarone-induced pulmonary toxicity. To investigate this possibility, female rats were given a single intratracheal instillation of amiodarone (6.25 mg/kg), its metabolite desethylamiodarone (5 mg/kg), or vehicle (sterile water). At 1, 2, 3, or 6 wk after treatment the lungs were lavaged and the recovered cells were counted and identified. The alveolar macrophages were isolated by attachment to plastic petri dishes, cultured overnight, and the spent media collected for tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) analyses. Desethylamiodarone treatment resulted in a neutrophilic alveolitis, but the levels of TNF-alpha and TGF-beta were not significantly different from control animals. In contrast, amiodarone treatment resulted in a lymphocytic alveolitis and significantly higher amounts of TNF-alpha were observed at 3 and 6 wk after treatment. A trend toward higher levels of TGF-beta was also noted in the amiodarone-treated group at wk 1-3 but the values were not significantly different from those of controls. In conclusion, the release of TNF-alpha may play a role in the development of amiodarone-induced pulmonary toxicity.     

Effects of interferons on tumour necrosis factor alpha production from human keratinocytes

Interferons (IFNs) have been reported to have pleiotrophic effects including the ability to induce the production of other cytokines in several cell types. Tumour necrosis factor alpha (TNF-alpha) is pro-inflammatory cytokine a known to be produced by a variety of cells including human keratinocytes. In the present study, we sought to determine the effects of IFNs on TNF-alpha production from human keratinocytes. IFN-gamma (50-100 ng/ml) induced TNF-alpha production dose dependently, but no induction of TNF-alpha was observed with IFN-alpha or IFN-beta. Since in the epidermis cytokines often work with in a cascade fashion and keratinocytes are a source of primary cytokine, IL-1 alpha, whether combined treatment with IFN-gamma and IL-1 alpha had a synergistic effect on TNF-alpha production was examined. Combined treatment with IFN-gamma (100 ng/ml) and IL-1 alpha (10 ng/ml) induced 2-3-fold higher level of TNF-alpha than IL-1 alpha alone. These results suggest that IFN-gamma is a positive regulator for the production of TNF-alpha from human keratinocytes and likely to increase skin inflammation.     

Effects of phagocytosis of mineral dusts on elastase secretion by alveolar and peritoneal exudative macrophages

Peritoneal exudative and alveolar macrophages secrete a nonlysosomal neutral protease which hydrolyses particulate elastin suspended in agar. A variety of particles were administered to macrophages in culture to determine their effect on the secretion of this elastase. Among the particles were silica, two types of asbestos, and kaolinite--all minerals implicated in the production of lung diseases accompanied by reorganization of connective tissue. Peritoneal exudative macrophages increased their secretion of elastase in response to phagocytosis of all the pathogenic particles examined. The increase, however, was not as great as that observed with latex beads, the most inert particles. Although these same particle types were phagocytized by cultured alveolar macrophages, none of them augmented the elastase secretion of alveolar macrophages above the resting level, and many decreased it. The lessened stimulation of elastase secretion by peritoneal macrophages and the decrease in the resting level of elastase secretion of alveolar macrophages probably reflect the cytotoxicity of the particles.     

Effect of cyclosporin A on inflammatory cytokine production by human alveolar macrophages

OBJECTIVES: Oromandibular dystonia (OMD) is a focal dystonia manifested by involuntary muscle contractions producing repetitive, patterned mouth, jaw, and tongue movements. Dystonia is usually idiopathic (primary), but in some cases it follows peripheral injury. Peripherally induced cervical and limb dystonia is well recognised, and the aim of this study was to characterise peripherally induced OMD. METHODS: The following inclusion criteria were used for peripherally induced OMD: (1) the onset of the dystonia was within a few days or months (up to 1 year) after the injury; (2) the trauma was well documented by the patient's history or a review of their medical and dental records; and (3) the onset of dystonia was anatomically related to the site of injury (facial and oral). RESULTS: Twenty seven patients were identified in the database with OMD, temporally and anatomically related to prior injury or surgery. No additional precipitant other than trauma could be detected. None of the patients had any litigation pending. The mean age at onset was 50.11 (SD 14.15) (range 23-74) years and there was a 2:1 female preponderance. Mean latency between the initial trauma and the onset of OMD was 65 days (range 1 day-1 year). Ten (37%) patients had some evidence of predisposing factors such as family history of movement disorders, prior exposure to neuroleptic drugs, and associated dystonia affecting other regions or essential tremor. When compared with 21 patients with primary OMD, there was no difference for age at onset, female preponderance, and phenomenology. The frequency of dystonic writer's cramp, spasmodic dysphonia, bruxism, essential tremor, and family history of movement disorder, however, was lower in the post-traumatic group (p<0.05). In both groups the response to botulinum toxin treatment was superior to medical therapy (p<0.005). Surgical intervention for temporomandibular disorders was more frequent in the post-traumatic group and was associated with worsening of dystonia. CONCLUSION: The study indicates that oromandibular-facial trauma, including dental procedures, may precipitate the onset of OMD, especially in predisposed people. Prompt recognition and treatment may prevent further complications.     

Inhibition of tumour necrosis factor (TNF) production by antimalarial drugs used in cerebral malaria

A pseudoaneurysm after percutaneous coronary angioplasty (PTCA) of the left anterior descending coronary artery is reported in a 52-year-old woman who underwent PTCA for exertional angina and a significant isolated stenosis of the left anterior descending coronary artery. Intravascular ultrasonography during repeat coronary angiography clearly identified a localized coronary dilation at the PTCA site in conventional coronary angiography as a pseudoaneurysm that was confirmed during surgery.     

Production of tumor necrosis factor alpha and interleukin-6 by alveolar macrophages from patients with rheumatoid arthritis and interstitial pulmonary disease

The aim of this study was to measure the production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) by alveolar macrophages in patients with rheumatoid arthritis and interstitial lung disease (ILD). Rheumatoid arthritis patients diagnosed by ACR criteria (n = 8) with associated ILD documented by pulmonary function tests and high resolution computerized tomography scanning, and 12 healthy volunteers (6 smokers and 6 nonsmokers). We determined the spontaneous and induced production of bacterial lipopolysaccharides (LSP), TNF-alpha and IL-6 by alveolar macrophages obtained by bronchoalveolar lavage. The macrophages were isolated by Ficoll-Hypaque gradient centrifugation and plastic adherence and cultured in serum-containing medium (low endotoxin) in the presence and absence of LPS (100 ng/ml). TNF-alpha and IL-6 levels contents were determined in supernatants by ELISA. In the patient group both spontaneous and induced production of TNF-alpha were significantly higher than in controls (p < 0.01). Macrophages stimulated with LPS in patients with rheumatoid arthritis and ILD also released greater amounts of IL-6 than did those of the healthy controls. IL-6 spontaneous and induced production was significantly lower in smokers than in nonsmokers. TNF-alpha and IL-6 production in patients with rheumatoid arthritis and ILD, studied in bronchoalveolar lavage specimens reveals that alveolar macrophages are hyperreactive in these patients, who are possibly sensitized as a consequence of the inflammatory lung process inherent to the disease. Further study is needed to define the pathogenic role of these mediators.     

Effects and interactions of tumour necrosis factor alpha and bradykinin on interleukin-1 production in gingival fibroblasts

We examined the association of serum albumin concentration with diabetes mellitus and other cardiovascular risk factors, prevalent cardiovascular disease, and ultrasonographically assessed carotid artery intima-media thickness using data from 45- to 64-year-old adults in the Atherosclerosis Risk in Communities (ARIC) Study. The mean albumin concentration was 0.04 to 0.12 g/L lower in participants with diabetes and 0.02 to 0.06 g/L lower in those with cardiovascular disease, compared to participants without these conditions. However, lower serum albumin level was also correlated with most traditional risk factors and hemostatic variables. On adjustment for these, there was essentially no association between serum albumin and prevalent cardiovascular disease. Likewise, there was no association between albumin and carotid intima-media thickness (a marker of atherosclerosis). While hypoalbuminemia may be a marker for chronic disease and perhaps renal loss of albumin, it seems unlikely that it is an important cause of atherosclerosis.     

Influence of beta-endorphin on the production of reactive oxygen and nitrogen intermediates by rabbit alveolar macrophages

We have compared the cuffed oropharyngeal airway (COPA), a modified Guedel airway device with a specially designed cuff at its distal end, with the laryngeal mask airway (LMA), on haemodynamic and electroencephalographic (EEG) responses to insertion. In addition, we examined the haemodynamic and EEG changes during initiation of the effect-compartment controlled infusion. We studied 35 female patients undergoing ambulatory gynaecological surgery allocated randomly to received an LMA or COPA to manage the airway. After premedication with midazolam 0.03 mg kg-1 i.v. and low-dose alfentanil (0.01 mg kg-1), anaesthesia was induced and maintained with propofol, using an effect-compartment controlled infusion set at an effect-site concentration of 4 micrograms ml-1. After intercompartmental equilibration, the LMA (group I) or COPA (group II) was inserted and haemodynamic (arterial pressure, heart rate) and EEG (bispectral index (BIS)) responses to insertion studied. The effect-compartment controlled infusion of propofol caused only mild haemodynamic changes during induction. Changes in arterial pressure and heart rate after insertion were similar in both groups and not significantly different from baseline values before insertion. Changes in BIS after insertion were minor and similar between groups.     

Synergistic antitumour effect of recombinant human tumour necrosis factor alpha with melphalan in isolated limb perfusion in the rat

The efficacy of isolated limb perfusion (ILP) for 'intransit' metastases from malignant melanoma and irresectable soft tissue sarcoma has been improved considerably by the addition of tumour necrosis factor (TNF) alpha. A rat sarcoma tumour model was, therefore, developed to evaluate the effects of TNF-alpha, melphalan and the combination of these drugs in the treatment of sarcoma. In BN rats bearing the non-immunogenic BN 175 sarcoma ILPs were performed with perfusate only, TNF-alpha, melphalan alone, or in combination when tumours had grown to approximately 1.5 cm in diameter. All rats treated with sham perfusion or perfusion with 50 micrograms TNF-alpha showed progressive disease. After perfusion with 40 micrograms melphalan no change in tumour diameter was observed in any rats at 4 days. After a combined perfusion with 40 micrograms melphalan and 50 micrograms TNF-alpha complete remission was noted in 12 of 16 rats. This synergistic effect in vivo between relatively ineffective doses of TNF-alpha and melphalan was not observed in vitro.     

Smoking and preterm labor: effect of a cigarette smoke extract on the secretion of platelet-activating factor-acetylhydrolase by human decidual macrophages

OBJECTIVE: Maternal smoking in pregnancy is associated with a significant increase in the incidence of preterm labor, premature rupture of membranes, and premature delivery. Our aim was to clarify the cause underlying this association. STUDY DESIGN: The effect of cigarette smoke extract on the secretion of platelet-activating factor-acetylhydrolase by both decidual macrophages and peripheral blood monocytes and macrophages was investigated. RESULTS: The cigarette smoke extract inhibited the platelet-activating factor-acetylhydrolase secretion by these cells. The inhibitory effect of cigarette smoke extract on the secretion was a hundred times more potent compared with its direct effect on the plasma enzyme. Glutathione and dithiothreitol blocked the inhibition, whereas catalase or superoxide dismutase did not. Nicotine and cotinine have no effect on the secretion. CONCLUSION: The presence in cigarette smoke extract of a potent inhibitor(s) of platelet-activating factor-acetylhydrolase secretion by decidual macrophages may provide an insight into the pathogenesis of preterm labor, premature rupture of membranes, and premature delivery in women who smoke during pregnancy.     

Tumor necrosis factor soluble receptor 75: the principal receptor form released by human alveolar macrophages and monocytes in the presence of interferon gamma

Tumor necrosis factor alpha(TNF alpha), a proinflammatory cytokine secreted predominantly by monocytemacrophages, interacts with two cell-surface receptors: TNF-R55 and TNF-R75. Few studies have been devoted to their modulation on human alveolar macrophages (AM). Both source and target of TNF(alpha), AM also release its inhibitors, the soluble receptors, following the cleavage of the extracellular domain of TNF-R55 and TNF-R75. Because in vivo AM are subject to activation by exogenous or endogenous stimuli, we analyzed the release of both receptors into the cell culture supernatant in response to lipopolysaccharide (LPS), phorbol myristate acetate (PMA), and cytokines such as interleukin 2(IL-2), IL-4, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon gamma (IFN-gamma). Results were compared with those obtained on peripheral blood monocytes (Mo), and the role of receptor recycling was investigated using inhibitors such as monensin and chloroquine. In our culture conditions, basal release by unstimulated AM amounted to 0.3 +/- 0.1 and 0.5 +/- 0.1 ng/ml for TNF-sR55 and TNF-sR75, respectively. In the same conditions, Mo released 1.2 +/- 1.2 ng/ml of TNF-sR55 and 5.1 +/- 0.1 ng/ml of TNF-sR75. PMA slightly increased mRNA expression and release of TNF-sR55, but those of TNF-sR75 were enhanced approximately 4-fold. After 24 h of culture, the release of TNF-sR75 was 2.5-fold higher on Mo than on AM. Of the cytokines tested on AM, IFN-gamma increased the release of TNF-sR75 3-fold, but that of TNF-sR55 only between 1.5- and 2-fold. GM-CSF enhanced them to a lower extent (approximately 1.5-fold). Shedding occurred despite the presence of chloroquine, monensin and colchicine, suggesting that cleavage takes place on the cell surface rather than after internalization. Addition of colchicine increased the release of TNF-sR75 induced by LPS and IFN-gamma, but not by PMA. In conclusion, Mo and AM differ in their ability to release TNF(alpha) and TNF-sR. On AM the release of each receptor appears to be regulated separately. Finally, IFN-gamma was among the most efficacious cytokines to induce the release of both receptors, with TNF-sR75 being more liable to shedding. Thus, the two TNF-R seem to be ruled by separate mechanisms and to differ in terms of release sensitivity.     

Effects of human immunodeficiency virus and colony-stimulating factors on the production of interleukin 6 and tumor necrosis factor alpha by monocyte/macrophages

Patients infected with human immunodeficiency virus (HIV) frequently have increased production of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha), and these cytokines may in turn contribute to the disease pathogenesis. It has been hypothesized that secretion of these cytokines by HIV-exposed mononuclear cells or HIV-infected monocyte/macrophages (M/Ms) is the principal source of their overproduction in HIV-infected patients, and the present study was undertaken to explore this issue. We observed that in the absence of endotoxin or cytokines, M/Ms productively infected by HIV do not produce detectable IL-6 or TNF-alpha. However, granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine that enhances HIV replication in M/Ms and is frequently used to propagate monocytotropic strains of HIV, can induce the relatively long-term production of IL-6 (up to 47 U/ml) and TNF-alpha (up to 47 pg/ml) by M/Ms, even in the absence of HIV. Also, HIV induced production of a relatively small (< or = 9 U/ml) quantity of IL-6 in M/Ms stimulated with macrophage-colony stimulating factor (M-CSF). Finally, while highly concentrated HIV induced production of both cytokines by either M/Ms or peripheral blood mononuclear cells (PBMCs), this production was almost completely eliminated when care was taken to avoid contamination of HIV by endotoxin. These data suggest that the excess IL-6 and TNF-alpha in HIV-infected patients does not simply result from their production by HIV-infected M/Ms and that alternative mechanisms are involved in this process.     

Effect of exposure of guinea pigs to cigarette smoke on elastolytic activity of pulmonary macrophages

STUDY OBJECTIVE: To determine the effect of exposure to cigarette smoke on the elastolytic activity of guinea pigs' alveolar macrophages (AMs), and to compare elastolytic activity of AMs obtained by BAL with that of lung macrophages (LMs) obtained from minced lung tissue. METHODS: AMs were obtained by BAL from seven adult guinea pigs exposed to cigarette smoke for 5 d/wk during 6 weeks, as well as from age-matched control guinea pigs. From each animal, one lung was used to obtain LMs by mincing and teasing the lung, followed by enzymatic digestion and isolation of mononuclear cells by Hypaque-Ficoll separation. The other lung was inflated and fixed to quantitate emphysema by the destructive index (DI). Elastolytic activity (microgram of elastin degraded by 10(6) macrophages) was determined at 24, 48, and 72 h, by culturing AMs and LMs (1 x 10(6) cells in 1 mL of medium) in 3H-elastin-coated wells. RESULTS: In animals exposed to cigarette smoke, the total number of BAL cells (8.6+/-2.1 x 10(6)) and DI (21.8+/-8.1) were significantly higher than in nonexposed animals (6.4+/-1.8 x 10(6), p<0.05 for cells, and 12.1+/-4.1, p<0.01 for DI). Elastolytic activity of AMs from smoke-exposed guinea pigs was significantly higher at 24, 48, and 72 h than elastolytic activity of AMs from control animals (19.0+/-9.4 vs 10.0+/-5.3, p<0.05 at 72 h). Likewise, elastolytic activity of LMs was significantly higher in exposed than nonexposed guinea pigs (11.8+/-7.7 vs 7.4+/-5.0 at 72 h, p<0.05). Elastolytic activity of LMs was not significantly different from elastolytic activity of AMs, both in exposed guinea pigs (11.8+/-7.7 vs 19.0+/-9.4 at 72 h) and nonexposed animals (7.4+/-5.0 vs 10.0+/-5.3 at 72 h). CONCLUSIONS: These results indicate that elastolytic activity of both AMs and LMs of guinea pigs increases significantly after exposure to cigarette smoke and that AMs and LMs have similar elastolytic activities.     

Synergistic effects of prostaglandin F2alpha and tumor necrosis factor to induce luteolysis in the pig

Telomerase activity was detected in germ cells, stem cells and cancer cells. In tumors of the ovary, an organ that contains germ cells, the authors examined availability to detect telomerase activity. Telomerase activity of malignant tumors was extremely high compared with that of normal ovaries and benign tumors. Strength and frequency of telomerase activity in malignant tumors was significant different from that in benign tumors. Telomere length tended to be smaller for malignant tumors of advanced stage, but no significant relationship between telomere length and telomerase activity and tumor stage could be recognized. Telomerase activity may be a useful marker for the diagnosis of ovarian tumors.     

Chronic smoke exposure alters the phenotype pattern and the metabolic response in human alveolar macrophages

PURPOSE: To investigate the regional differences in small intestinal (SI) metabolism and permeability for several compounds and to ascertain the potential significance of these differences on the reported reductions in regional bioavailability in humans. METHODS: The regional SI metabolism and permeability of captopril, didanosine (ddI), mannitol, ofloxacin and zidovudine (ZDV) were investigated in rats using a Single Pass Perfusion (SPIP) procedure or intestinal homogenates. RESULTS: ddI was metabolized to a greater extent in the upper SI whereas captopril was metabolized to a greater extent in the lower SI. Relatively low homogenate concentrations resulted in significant degradation of captopril in the upper and lower SI. All other compounds were stable and changes in the buffer system or the initial concentration did not affect the results. The SI permeabilities of all compounds, with the exception of mannitol, decreased linearly with respect to SI location and the slopes of the corresponding normalized regression lines were not significantly different. CONCLUSIONS: It has been reported that captopril and ddI demonstrate regional intestinal bioavailability in several species including humans. The current results suggest that the reported reduction in the lower SI bioavailability of captopril may be a result of a reduction in permeability and an increase in intestinal metabolism whereas for ddI, the reduction in the lower SI bioavailability appears to be attributable to a reduction in intestinal permeability. Other factors such as luminal metabolism may also significantly effect regional differences in the intestinal bioavailability of ddI or captopril. Based on these results, a strong possibility exists that ofloxacin and ZDV may also demonstrate regional differences in intestinal bioavailability.