Decreased leukotriene B4 synthesis in smokers' alveolar macrophages in vitro

Radiation Pneumonitis: Old Problem, New Tricks

Radiation therapy is a major treatment modality for management of non-small cell lung cancer. Radiation pneumonitis is a dose limiting toxicity of radiotherapy, affecting its therapeutic ratio. This review presents patient and treatment related factors associated with the development of radiation pneumonitis. Research focusing on reducing the incidence of radiation pneumonitis by using information about lung ventilation, imaging-based biomarkers as well as normal tissue complication models is discussed. Recent advances in our understanding of molecular mechanisms underlying lung injury has led to the development of several targeted interventions, which are also explored in this review.

The Influence of Patient-related Constutional and Environmental Factors on Early Results of a Combined Modality Therapy of Esophageal Cancer

Among many various factors affecting the outcome of cancer treatment one can distinguish patient, tumor- and treatment-related factors. The association of patient-related factors and results of a combined modality therapy of esophageal cancer has not been extensively explored. The aim of the study was to analyze the impact of patient-related constitutional and environmental factors on early results of combined modality therapy of esophageal squamous cell carcinoma.

MATERIAL AND METHODS

We retrospectively analyzed prospectively collected data of 84 patients with esophageal cancer randomly assigned to a combined modality treatment. We evaluated the relationship between early outcome of neoadjuvant therapy (overall toxic events, serious toxic events, treatment-related mortality, clinical and pathological response to the treatment) or surgical treatment (postoperative morbidity, mortality and curative resections - R0) and constitutional (age, gender, height, body mass index, Karnofski Performance Status - KPS, blood type) or environmental (inhabitation, smoking duration and intensity, frequency and amount of alcohol consumption and occupational exposure) patient-related factors.

RESULTS

Significantly more neoadjuvant therapy related deaths were found in patients with KPS 70-80 (p=0.0016). Interestingly, significantly more toxic events (p=0.0034) after neoadjuvant therapy and a higher postoperative morbidity rate (p=0.0293) were observed in nonsmokers. Similarly, significantly more toxic events (p=0.0029) after neoadjuvant therapy and a higher postoperative mortality rate (p=0.0405) were found in light drinkers.

CONCLUSIONS

Smoking and consumption of excessive amount of alcohol may attenuate toxic effect of neoadiuvant and surgical therapy in patients treated due to esophageal cancer. The information regarding the mentioned above addictions should not result in giving up an attempt to provide a curative treatment.

The effect of smoking and major vein resection on post-therapy lymphedema in soft tissue sarcomas treated with neoadjuvant radiation and limb-salvage surgery

BACKGROUND

Neoadjuvant therapy with radiation +/- chemotherapy is an accepted management for soft tissue sarcomas (STS). The incidence of post-therapy lymphedema is around 30%. The purpose of this study was to identify variables that predict for post-therapy lymphedema.

METHODS

From 2000 to 2010, 132 patients with STS were treated with neoadjuvant radiation +/- chemotherapy followed by resection. Patient variables and treatment outcomes were reviewed. Presence of lymphedema was determined by the treating physician. The Fisher exact test was used for univariate analysis and logistic regression was used for multivariate analysis.

RESULTS

Median follow-up was 3.1 years. Of the lower extremity STS, major veins were sacrificed in 34% of patients. Lymphedema occurred in 22.4% of patients. Smoking negatively predicted for lymphedema on univariate analysis (P=0.007), and sacrifice of a major vein was associated with an increased risk of lymphedema (P=0.02). On multivariate analysis, smoking (P=0.02, odds ratio 0.31) negatively predicted for and sacrifice of a major vein (P=0.03, odds ratio 2.7) positively predicted for lymphedema.

CONCLUSIONS

There may be an association between smoking and decrease post-therapy lymphedema. Also, patients who undergo resection of a major vein seem to be more prone to post-therapy lymphedema.

The role of leukotriene B4 in early stages of experimental paracoccidioidomycosis induced in phenotypically selected mouse strains

Paracoccidioidomycosis is a human systemic mycosis caused by the fungus Paracoccidioides brasiliensis. The mechanisms involved in innate immune response to this fungus are not fully elucidated. Leukotrienes are known to be critical for the clearance of various microorganisms, mainly by mediating the microbicidal function of phagocytes. We investigated the involvement of leukotriene B4 in the early stages of experimental paracoccidioidomycosis, which was induced by intratracheal inoculation of the fungus in selected mouse lines. The mouse lines utilized were produced through bi-directional phenotypic selection, endowed with maximal or minimal acute inflammatory reactivity, and designated AIRmax and AIRmin, respectively. AIRmax mice were more resistant to the infection, which was demonstrated by reduced lung fungal loads. However, the two lines produced similar amounts of leukotriene B4, and pharmacological inhibition of this mediator provoked similar fungal load increases in the two lines. The lower fungal load in the AIRmax mice was associated with a more effective inflammatory response, which was characterized by enhanced recruitment and activation of phagocytic cells and an increased production of activator cytokines. This process resulted in an increased release of fungicidal molecules and a diminution of fungal load. In both lines, leukotriene production was associated with a protective response in the lung that was consequent to the effect of this eicosanoid on the influx and activation of phagocytes.

Signal transduction pathways linking the activation of alveolar macrophages with the recruitment of neutrophils to lungs in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem. It is predicted by the World Health Organization to become the third most common cause of death and the fifth most common cause of disability in the world by 2020. COPD is a complex inflammatory disease involving several types of inflammatory cells and multiple inflammatory mediators. Although abnormal numbers of inflammatory cells such as macrophages, dendritic cells, neutrophils, and T lymphocytes have been documented in COPD, the relationship between these cell types and the sequence of their appearance and persistence is largely unknown. Alveolar macrophages have been identified as one of the major cell types that plays a key role in orchestrating the inflammatory events associated with the pathophysiology of COPD. One of the major functions of macrophages is the secretion of chemotactic factors and this function is markedly increased on exposure to cigarette smoke (CS). This enhanced release of chemoattractants results in increased lung neutrophil infiltration, which is thought to be a key event in the development of COPD. The molecular basis for this amplified inflammatory response is not very clear, but it could be due to an alteration in signal transduction pathways within the macrophage. Based on existing literature, an attempt has been made to create a comprehensive review of the signal transduction pathways that link the activation of macrophages with the increased recruitment of neutrophils into the airways. Some of the major stimuli that activate macrophages and cause them to secrete chemotactic factors have been identified as CS, wood smoke, ozone, bacterial endotoxin, and proinflammatory cytokines such as interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. These stimuli seem to activate mainly redox-sensitive transcription factors such as nuclear factor (NF)-kappa B and activator protein (AP)-1, both of which play a major role in the synthesis and secretion of chemotactic factors such as IL-8 and leukotriene B(4) (LTB(4)). The pathways involved in the synthesis and secretion of other factors such as macrophage chemotactic protein-1 (MCP-1) and growth-related oncogene-alpha (Gro-alpha) have also been reviewed.

Corticosteroid suppression of lipoxin A4 and leukotriene B4 from alveolar macrophages in severe asthma

BACKGROUND

An imbalance in the generation of pro-inflammatory leukotrienes, and counter-regulatory lipoxins is present in severe asthma. We measured leukotriene B4 (LTB4), and lipoxin A4 (LXA4) production by alveolar macrophages (AMs) and studied the impact of corticosteroids.

METHODS

AMs obtained by fiberoptic bronchoscopy from 14 non-asthmatics, 12 non-severe and 11 severe asthmatics were stimulated with lipopolysaccharide (LPS,10 microg/ml) with or without dexamethasone (10(-6)M). LTB4 and LXA4 were measured by enzyme immunoassay.

RESULTS

LXA4 biosynthesis was decreased from severe asthma AMs compared to non-severe (p < 0.05) and normal subjects (p < 0.001). LXA4 induced by LPS was highest in normal subjects and lowest in severe asthmatics (p < 0.01). Basal levels of LTB4 were decreased in severe asthmatics compared to normal subjects (p < 0.05), but not to non-severe asthma. LPS-induced LTB4 was increased in severe asthma compared to non-severe asthma (p < 0.05). Dexamethasone inhibited LPS-induced LTB4 and LXA4, with lesser suppression of LTB4 in severe asthma patients (p < 0.05). There was a significant correlation between LPS-induced LXA4 and FEV1 (% predicted) (r(s) = 0.60; p < 0.01).

CONCLUSIONS

Decreased LXA4 and increased LTB4 generation plus impaired corticosteroid sensitivity of LPS-induced LTB4 but not of LXA4 support a role for AMs in establishing a pro-inflammatory balance in severe asthma.

Survey of the level of anti-HBs antibody titer in vaccinated Iranian general dentists

Hepatitis B is an infectious disease to which dentists are susceptible. The main aim of this study was to determine the level of antibody titer and immunity in vaccinated Iranian general dentists. A total of 861 general dentists were invited to participate in this study; 598 persons who could recall their history of vaccination and consented to have blood samples taken were recruited. Demographic and work-related data were recorded, and anti-Hepatitis B surface antigen (anti-HBs-Ag) evaluations were measured using the enzyme-linked immunosorbent assay (ELISA). Of the 598 participants, 35 (5.9%) were nonimmune (anti-HBs <10 IU/l), 101 (16.9%) were relatively immune (anti-HBs = 10-99 IU/l), and 462 (77.3%) were completely immune (anti-HBs > or =100 IU/l). Only 218 (36.5%) of the dentists knew their HBs antibody titer. Fourteen (2.3%) persons reported receiving one dose and 65 (10.9%) had received two doses. The number of those who had received the three recommended doses totaled 519 (86.8%), 491 (82.1%) of them receiving their vaccine on schedule. Age, city, pack-years of smoking, years of smoking, and the interval between the last vaccination and the commencement of the study had a significant relationship to the antibody titer level, whereas sex, marital status, place of practice, smoking, and vaccination schedule were not related. Only 36.5% of the general dentists had checked their antibody titer. We, therefore, recommend that dentists, as a potential high-risk group, should know their level of anti-HBs antibody titer so that those who require revaccination can get treatment.

Phosphorylation of serine 271 on 5-lipoxygenase and its role in nuclear export

The enzyme 5-lipoxygenase (5-LO) initiates the biosynthesis of leukotrienes, inflammatory mediators involved in immune diseases and defense. The subcellular localization of 5-LO is regulated, with nuclear import commonly leading to increased leukotriene production. We report here that 5-LO is constitutively phosphorylated on Ser-271 in transfected NIH 3T3 cells. This residue is nested in a classical nuclear export sequence, and phosphorylated Ser-271 5-LO was exclusively found in the nucleus by immunofluorescence and by fractionation techniques. Mutation of Ser-271 to Ala allowed nuclear export of 5-LO that was blocked by the specific nuclear export inhibitor leptomycin b, suggesting that phosphorylation of Ser-271 serves to interfere with exportin-1-mediated nuclear export. Consistent with previous reports that purified 5-LO can be phosphorylated on Ser-271 in vitro by MAPK-activated protein kinase 2, the nuclear export of 5-LO was increased by either treatment with the p38 inhibitor SB 203,580 or co-expression of a kinase-deficient p38 MAPK. Nuclear export of 5-LO can also be induced by KN-93, an inhibitor of Ca2+/calmodulin-dependent kinase II, and the effects of SB 203,580 plus KN-93 are additive. Finally, HeLa cells, which lack nuclear 5-LO, also lack constitutive phosphorylation of Ser-271. Taken together, these results indicate that the phosphorylation of Ser-271 serves to inhibit the nuclear export of 5-LO. This action works in concert with nuclear import, which is regulated by phosphorylation on Ser-523, to determine the subcellular distribution of 5-LO, which in turn regulates leukotriene biosynthesis.

Dose-volume thresholds and smoking status for the risk of treatment-related pneumonitis in inoperable non-small cell lung cancer treated with definitive radiotherapy

PURPOSE

To identify clinical risk factors and dose-volume thresholds for treatment-related pneumonitis (TRP) in patients with non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Data were retrospectively collected from patients with inoperable NSCLC treated with radiotherapy with or without chemotherapy. TRP was graded according to Common Terminology Criteria for Adverse Events, version 3.0, with time to grade > or = 3 TRP calculated from start of radiotherapy. Clinical factors and dose-volume parameters were analyzed for their association with risk of TRP.

RESULTS

Data from 576 patients (75% with stage III NSCLC) were included in this study. The Kaplan-Meier estimate of the incidence of grade > or = 3 TRP at 12 months was 22%. An analysis of dose-volume parameters identified a threshold dose-volume histogram (DVH) curve defined by V(20) < or = 25%, V(25) < or = 20%, V(35) < or = 15%, and V(50) < or = 10%. Patients with lung DVHs satisfying these constraints had only 2% incidence of grade > or = 3 TRP. Smoking status was the only clinical factor that affected the risk of TRP independent of dosimetric factors.

CONCLUSIONS

The risk of TRP varied significantly, depending on radiation dose-volume parameters and patient smoking status. Further studies are needed to identify biological basis of smoking effect and methods to reduce the incidence of TRP.

Leukotrienes: underappreciated mediators of innate immune responses

Leukotrienes are bronchoconstrictor and vasoactive lipid mediators that are targets in the treatment of asthma. Although they are increasingly recognized to exert broad proinflammatory effects, their role in innate immune responses is less well appreciated. These molecules are indeed synthesized by resident and recruited leukocytes during infection. Acting via cell surface G protein-coupled receptors and subsequent intracellular signaling events, they enhance leukocyte accumulation, phagocyte capacity for microbial ingestion and killing, and generation of other proinflammatory mediators. Interestingly, a variety of acquired states of immunodeficiency, such as HIV infection and malnutrition, are characterized by a relative deficiency of leukotriene synthesis. The data reviewed herein point to leukotrienes as underappreciated yet highly relevant mediators of innate immunity.

Distinct roles of eicosanoids in the immune response to viral encephalitis: or why you should take NSAIDS

Prostaglandins (PGs) and leukotrienes (LTs) are important proinflammatory mediators. They are both derived from arachidonic acid (AA). Cyclooxygenase (COX), the key enzyme in transforming AA into PGs, has two isoforms: COX-1 is constitutively expressed, and COX-2, is inducible. Lipoxygenase (5-LO) is the key enzyme for LT production. PGs and LTs have been intensively studied. Release of these molecules is associated with mucus secretion, redness, pain, fever and other inflammatory manifestations. Both PGs and LTs are involved in host defense against various pathogens. In addition to mediating inflammatory symptoms, PGs might suppress some innate immune factors, including nitric oxide (NO) production. PGs also suppress a TH1 response. LTs have pathologic potential, especially in asthma. LTs also have been found to have positive roles in host defense, either against virus or bacteria. Finally, PGs and LTs might regulate the production of each other, possibly at the level of substrate competition by their enzymes. Because they are clinically important molecules, a further understanding of the roles that PGs and LTs played in host defense will have great impact on therapeutic research.

Increased levels of interleukin-8 in BAL fluid from smokers susceptible to pulmonary emphysema

BACKGROUND

It has previously been shown that smokers with computed tomographic (CT) evidence of subclinical emphysema have signs of neutrophil activation, despite having no appreciable increase in the number of neutrophils in their bronchoalveolar lavage (BAL) fluid.

METHODS

The levels of the following chemoattractants in BAL fluid from 61 community based older volunteers classified into four groups according to current smoking status and the presence or absence of emphysema were determined: interleukin 8 (IL-8), epithelial neutrophil activating protein 78 (ENA-78) and leukotriene B(4) (LTB(4)) which are primarily chemotactic for neutrophils; monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) which are predominantly chemotactic for mononuclear leucocytes.

RESULTS

Of the five chemoattractants studied, only the level of IL-8 in BAL fluid clearly distinguished between subjects with and without emphysema among current smokers (median values 34.7 and 12.2 pg/ml, respectively, p<0.01). In addition, the levels of IL-8 and neutrophil elastase-alpha(1) protease inhibitor complex in BAL fluid were significantly correlated (r=0.65, p<0.01). There was no difference in either the release of IL-8 from cultured alveolar macrophages at 24 hours or the expression of IL-8 messenger RNA of alveolar macrophages in the two groups of current smokers with and without emphysema.

CONCLUSION

An accelerated response of IL-8 to chronic smoking is a factor that characterises those smokers who are susceptible to pulmonary emphysema, although the cellular source of IL-8 remains to be determined.

Leukotrienes play protective roles early during experimental VSV encephalitis

Leukotrienes (LT) are potent lipid mediators of inflammation. 5-Lipoxygenase (5-LO) is the key enzyme in the conversion of arachidonic acid to LT. There are four LT: LTB(4), LTC(4), LTD(4) and LTE(4). LT have been extensively studied in airway inflammation but little is known about their roles in viral infection in the CNS. LTB(4) is a chemoattractant for neutrophils. In this work, we studied the roles of LT in acute vesicular stomatitis virus (VSV) encephalitis. Two methods were used to disrupt 5-LO activity: mice were treated with Zileuton, an enzyme antagonist, or 5-LO genetic knockout mice were used. We found that inhibition or deletion of 5-LO resulted in: (a) impaired process of neutrophil infiltration into the CNS early during viral infection; (b) fewer neurons expressed nitric oxide synthase-1 (NOS-1); (c) higher viral titers 1 day after viral infection; and (d) increased disruption of blood brain barrier (BBB). Our studies suggest that LT are important innate immune players during VSV pathogenesis and are beneficial to the host in early control of viral replication in the CNS.

Activation of the Phosphatidylinositol 3-Kinase-Akt/Protein Kinase B Signaling Pathway in Arachidonic Acid-stimulated Human Myeloid and Endothelial Cells

Although arachidonic acid has been demonstrated to stimulate a wide variety of cellular functions, the responsible mechanisms remain poorly defined. We now report that arachidonic acid stimulated the activity of class Ia phosphatidylinositol 3-kinase (PI3K) in human umbilical vein endothelial cells, HL60 cells, and human neutrophils. Pretreatment of endothelial cells with AG-1478, an inhibitor of the ErbB receptor family, resulted in the suppression of PI3K activation by arachidonic acid. The fatty acid enhanced the tyrosine phosphorylation of ErbB4 but not of ErbB2 or ErbB3. The ability of arachidonic acid to stimulate PI3K activity in neutrophils was suppressed by indomethacin and nordihydroguaiaretic acid, inhibitors of the cyclooxygenases and lipoxygenases, respectively, but not by 17-octadecynoic acid, an inhibitor of omega-hydroxylation of arachidonic acid by cytochrome P450 monooxygenases. Consistent with this, the activity of PI3K in neutrophils was stimulated by 5-hydroxyeicosatetraenoic acid. Arachidonic acid also transiently stimulated the phosphorylation of Akt on Thr-308 and Ser-473. Although PI3K was not required for the activation of the mitogen-activated protein kinases, ERK1, ERK2, and p38, in arachidonic acid-stimulated neutrophils, the fatty acid acted via PI3K to stimulate the respiratory burst. These results not only define a novel mechanism through which some of the actions of arachidonic acid are mediated but also demonstrate that, in addition to ErbB1 (epidermal growth factor receptor), ErbB4 can also be transactivated by a non-epidermal growth factor-like ligand.

Effects of cigarette smoking on gastric ulcer formation and healing: possible mechanisms of action

Epidemiologic studies have shown that cigarette smoking is closely related to peptic ulcer disease. The mechanisms by which cigarette smoking adversely affects gastric mucosa have been suggested and elucidated. This article reviews some of the mechanisms involved in cigarette smoking-related gastric ulceration and healing. Experimental findings suggest that cigarette smoking increases xanthine oxidase activity, leukotrienes, and nitric oxide production and also neutrophil infiltration in the gastric mucosa. On the other hand, it reduces blood flow, prostaglandin production, epithelial cell proliferation, and formation of blood vessels in the tissue. These actions are important for ulcer formation and healing. The evidence thus far available strengthens the hypothesis that cigarette smoke is indeed harmful to gastric mucosa through defined mechanisms.

5-Lipoxygenase reaction products modulate alveolar macrophage phagocytosis of Klebsiella pneumoniae

The leukotrienes are potent lipid mediators of inflammation formed by the 5-lipoxygenase-catalyzed oxidation of arachidonic acid. Although the effects of leukotrienes on neutrophil chemotaxis and activation have been established, their role in modulating innate host defense mechanisms is poorly understood. In a previous study (M. Bailie, T. Standiford, L. Laichalk, M. Coffey, R. Strieter, and M. Peters-Golden, J. Immunol. 157:5221-5224, 1996), we used 5-lipoxygenase knockout mice to establish a critical role for endogenous leukotrienes in pulmonary clearance and alveolar macrophage phagocytosis of Klebsiella pneumoniae. In the present study, we investigated the role of specific endogenous leukotrienes in phagocytosis of K. pneumoniae and explored the possibility that exogenous leukotrienes could restore phagocytosis in alveolar macrophages with endogenous leukotriene synthesis inhibition and enhance this process in leukotriene-competent cells. Rat alveolar macrophages produced leukotriene B4 (LTB4), LTC4, and 5-hydoxyeicosatetraenoic acid (5-HETE) during the process of phagocytosis, and the inhibition of endogenous leukotriene synthesis with zileuton and MK-886 dramatically attenuated phagocytosis. We also observed a reduction in phagocytosis when we treated alveolar macrophages with antagonists to the plasma membrane receptors for either LTB4, cysteinyl-leukotrienes, or both. In leukotriene-competent cells, LTC4 augmented phagocytosis to the greatest extent, followed by 5-HETE and LTB4. These 5-lipoxygenase reaction products demonstrated similar relative abilities to reconstitute phagocytosis in zileuton-treated rat alveolar macrophages and in alveolar macrophages from 5-lipoxygenase knockout mice. We conclude that endogenous synthesis of all major 5-lipoxygenase reaction products plays an essential role in phagocytosis. The restorative and pharmacologic effects of LTC4, LTB4, and 5-HETE may provide a basis for their exogenous administration as an adjunctive treatment for patients with gram-negative bacterial pneumonia.

Effects of ongoing smoking on the development of radiation-induced pneumonitis in breast cancer and oesophagus cancer patients

PURPOSE

To investigate the influence of smoking on the development of radiation-induced pneumonitis in patients treated for breast and oesophagus cancer.

MATERIALS AND METHODS

This is a retrospective study on 405 females diagnosed with primary unilateral breast cancer stages 1 and 2 and 201 oesophagus carcinoma patients. The possibilities in Sweden to obtain detailed information from different medical records were used to collect data on smoking habits, radiation treatment and spontaneously reported pneumonitis. Radiation-induced pneumonitis was defined as a combination of roentgenographic infiltrate in the lung field involving an irradiated area on the chest X-ray and clinical symptoms such as non-productive cough and dyspnoea.

RESULTS

Six breast cancer patients had spontaneously reported pneumonitis. Five of them were non-smokers (P = 0.182) and the other was a former smoker. Eight of the oesophagus cancer patients had spontaneously reported radiation-induced clinical pneumonitis and they were all non-smokers (P = 0.022), except one, who was a pipe smoker. None of the patients who were cigarette smokers were recorded as developing clinical pneumonitis after irradiation.

CONCLUSION

These data could support the previous clinical observations and experimental studies that smoking depresses the frequency of radiation-induced pneumonitis. The present study as well as earlier observations could justify further studies concerning the possibility of an interaction of smoking with cancer treatment, both from the view of therapeutic failures and reduced adverse effects.

Release of prostaglandin E2 and leukotriene B4 by alveolar macrophages from patients with sarcoidosis

BACKGROUND

Mediators released by alveolar macrophages, as well as by T cells, play an important part in modulating local immune processes in sarcoidosis. Among alveolar macrophage secretory products, arachidonic acid metabolites are known to regulate inflammatory and immune reactions. It has been suggested that cyclo-oxygenase and lipoxygenase pathway metabolites of arachidonic acid modulate the evolution of the granulomatous inflammatory response in the lung differently.

METHODS

Alveolar macrophages recovered from the bronchoalveolar lavage (BAL) fluid of 32 patients with sarcoidosis in different states of disease activity and 10 normal subjects were evaluated for their ability to release prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). Alveolar macrophages were cultured in the presence or absence of opsonised zymosan (500 micrograms/ml), and PGE2 and LTB4 levels in the culture supernatants were determined by enzyme immunoassay (EIA).

RESULTS

Stimulated alveolar macrophages from patients with active sarcoidosis released higher LTB4 levels than those from normal subjects, but no differences in PGE2 release were observed between the two groups. The time course of LTB4 release by activated alveolar macrophages showed that normal cells produced similar levels of the hydroxyacid during the early and late times of culture while LTB4 release by activated cells from patients with sarcoidosis increased markedly after 60 minutes of culture, remaining elevated until 24 hours. Indomethacin (3 x 10(6) M) caused the expected inhibition of PGE2 formation without affecting LTB4 release.

CONCLUSIONS

These results suggest that alveolar macrophages from the BAL fluid of patients with active sarcoidosis are primed to release LTB4, which may contribute to the locally heightened immune response.

Evaluation of the effects of steroids on experimental septic lung injury

To evaluate the clinical usefulness of steroids for septic lung injury, we investigated the effects of methylprednisolone (MP) on this disorder using an experimental rat model of cecal ligation and puncture (CLP). While 92% of the rats that underwent CLP (CLP rats) died within 30 h, those given high-dose MP (30 mg/kg) just after the operation (CLP + MP rats) survived for a significantly longer period (p < 0.01). Concentrations of endotoxin (ET) in arterial blood were significantly higher in the CLP + MP rats than in the CLP rats, while those in the bronchoalveolar lavage fluid (BALF) were significantly lower. Alveolar macrophages (AM) obtained from the CLP rats (CLP-AM) generated more O2-than did AM from sham-operated rats (sham-AM) following stimulation. However, the administration of MP did not reduce the upregulated generation of O2-by CLP-AM. While CLP-AM produced less leukotriene (LT)B4 than did sham-AM following stimulation with A23187, the administration of MP further reduced LTB4 production. When AM were cultured with [3H]arachidonic acid (3H-AA), the uptake of the isotope and the 3H release were significantly less in CLP-AM than in sham-AM. The administration of MP did not cause recoveries in the uptake and release of 3H-AA by CLP-AM. Although the survival time of CLP rats was significantly prolonged and the translocation of ET into BALF was reduced by steroid administration, the steroid effects were not explained by those on altered AM function. The upregulated generation of O2- and reduced LTB4 production from CLP-AM were not reversed by the treatment of this drug.

Reduction in leukotriene B4 generation by bronchoalveolar lavage cells in asthma

BACKGROUND

Leukotrienes are inflammatory mediators implicated in the pathogenesis of asthma. The capacity of inflammatory cells within the airways to generate leukotrienes may be altered in asthma. This hypothesis was tested using bronchoalveolar lavage (BAL) to sample cells within the airways from atopic asthmatic and normal subjects, and by measuring their capacity to generate leukotriene B4 (LTB4) and leukotriene C4 (LTC4) in response to A23187, a potent stimulus of leukotriene generation.

METHODS

Bronchoalveolar lavage was performed in 12 mild asymptomatic atopic asthmatic patients and 12 normal subjects. Mixed BAL cell aliquots (approximately 80% alveolar macrophages) were incubated with 0-20 microM A23187 for 10 minutes and with 4 microM A23187 for 0-30 minutes, and leukotrienes were measured by radioimmunoassay and high performance liquid chromatography.

RESULTS

Mixed BAL cells from asthmatic subjects generated less LTB4 than cells from normal subjects in dose response and time course experiments (area under the curve 81.5 (0.0-228.5) ng.min.10(-6) cells in asthmatic subjects and 197.9 (13.9-935.6) ng.min.10(-6) cells in normal subjects. There were no differences in LTC4 generation between BAL cells from asthmatic and normal subjects.

CONCLUSIONS

Generation of LTB4 by BAL cells from atopic asthmatic subjects in response to A23187 was reduced. As the alveolar macrophage is the major source of LTB4 in BAL cells, these results probably reflect reduced generation of LTB4 by alveolar macrophages from asthmatic patients. This may be a consequence of monocyte migration into the lung, or altered alveolar macrophage function in asthma, or both.

Effect of 3'-hydroxyfarrerol on airway hyperreactivity induced by acute cigarette smoke exposure in guinea pigs

The (+/-)-3'-hydroxyfarrerol (IdB 1031) is a new drug endowed with an interesting mucokinetic activity. In this study the effectiveness of IdB 1031 has been verified in a model of airway hyperreactivity and lung inflammation induced in anaesthetized guinea pig by active cigarette smoke exposure. IdB 1031 (500 mg/kg per os) completely inhibited the capacity of cigarette smoke to induce airway hyperreactivity. IdB 1031 also inhibited the recruitment of proinflammatory cells within the airway lumen as showed in bronchoalveolar lavage fluids. In line with these experiments IdB 1031 inhibited 5-lipoxygenase with an IC50 of 7.36 x 10(-6) M in human leukocytes challenged by A-23187 (2 microM). A significant reduction of the above parameters was observed also in animals exposed to smoke after repeated treatment with IdB 1031 at 200 mg/kg per os for 15 days. These results show that IdB 1031 is a promising drug with a favourable spectrum of activities on the respiratory tract.

Seasonal variation in the function of blood monocytes obtained from healthy nonsmokers, asymptomatic smokers, and smokers with chronic bronchitis

The present study focused on two questions: What effects do cigarette smoking and chronic bronchitis have on the function of the precursors of alveolar macrophages, the blood monocytes? Can seasonal variations affect the function of these cells? Phagocytic activity (the proportion of yeast-ingesting cells and the mean number of yeast particles per ingesting cell) and metabolism of arachidonic acid [secretion of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in zymosan-stimulated cultures] were studied as markers of monocyte function during three seasons: spring (May-June), autumn (November-December), and winter (February). Smokers with chronic bronchitis (SCBs) and asymptomatic smokers (ASs) had a lower proportion (p < 0.05) of ingesting monocytes than healthy nonsmokers (HNSs) during spring, but not during the other two seasons. The secretion of PGE2 was highest during autumn and lowest during spring in the monocytes of all three groups. In autumn, LTB4 secretion was increased in the monocytes of HNSs (p < 0.05) but not in those of ASs and SCBs. LTB4 secretion was similar in all groups during the other two seasons. Cigarette smoking and chronic bronchitis seem to impair the function of monocytes and may thereby affect the systemic host defense activity. Cells collected during autumn were generally more active than those sampled in spring, indicating marked seasonal variation in the function of monocytes from all three groups.

Effects of benzo(a)pyrene and nicotine on prostaglandin synthesis in buccal pouch and submandibular glands of the Syrian hamster

Adult male Syrian hamsters were treated by swabbing the apex of the buccal pouch with corn oil (control, C), 1 mM benzo(a)pyrene (BP), nicotine (NC), or BP+NC in corn oil, twice daily, 5 days a week. After a 4-week treatment, the pouches and submandibular glands were dissected and used for the determination of endogenous prostaglandin (PG) production and studies on in vitro PG synthesis. Of the three PGs analysed (PGE2, PGF2 alpha and 6-keto-PGF1 alpha), PGE2 was predominant in the pouch and the glands. BP or NC alone had only a weak effect on PG synthesis in both tissues. However, the combination of BP and NC had a synergistic effect, causing diminished PG synthesis in both tissues. In buccal pouch, BP+NC significantly decreased the concentrations of endogenous PGE2 and PGF2 alpha (PGE2: 0.669 +/- 0.254 versus 1.698 +/- 0.460, PGF2 alpha: 0.273 +/- 0.090 versus 0.625 +/- 0.272 ng/g tissue; BP+NC versus C; mean +/- SD, n = 5, p < 0.05). Similarly significant results were also found for in vitro PG synthesis (PGE2: 0.541 +/- 0.249 versus 1.399 +/- 0.340, PGF2 alpha: 1.045 +/- 0.428 versus 2.133 +/- 0.510 ng/g tissue; BP+NC versus C; mean +/- SD, n = 5, p < 0.05). In submandibular glands, BP+NC significantly diminished the concentration of endogenous PGE2 (1.183 +/- 0.175 versus 2.379 +/- 0.488 ng/g tissue; BP+NC versus C; mean +/- SD, n = 5, p < 0.05). The synthesis of 6-keto-PGF1 alpha in both tissues, and the synthesis of PGF2 alpha in submandibular gland, were slightly decreased with all treatments.

Human alveolar macrophages have 15-lipoxygenase and generate 15(S)-hydroxy-5,8,11-cis-13-trans-eicosatetraenoic acid and lipoxins

Eicosanoids derived from lipoxygenase (LO)-catalyzed reactions play important roles in pulmonary inflammation. Here, we examined formation of LO-derived products by human alveolar macrophages (HAM). HAM converted [1-14C]-arachidonic acid to a product carrying 14C-radiolabel that was identified as 15(S)-hydroxy-5,8,11-cis-13-trans-eicosatetraenoic acid (15-HETE) by physical methods. 15-LO mRNA was demonstrated in HAM by reverse transcription-polymerase chain reaction. Incubation of HAM for 3 d with interleukin 4(IL-4) before exposure to [1-14C]arachidonic acid led to both increased mRNA for 15-LO and a 4-fold increase in 15-HETE formation. In contrast, 5(S)-hydroxy-6-trans-8,11,14-cis-eicosatetraenoic acid generation was not significantly altered by prior exposure to IL-4. Additionally, lipoxins (LXA4 and LXB4) were detected from endogenous substrate, albeit in lower levels than leukotriene B4 (LTB4), in electrochemical detection/high performance liquid chromatography profiles from HAM incubated in the presence and absence of the chemotactic peptide (FMLP) or the calcium ionophore (A23187). Exposure of HAM to leukotriene A4 (LTA4) resulted in a 2-fold increase in LXA4 and 10-fold increase in LXB4. These results demonstrate the presence of 15-LO mRNA and enzyme activity in HAM and the production of LXA4 and LXB4 by these cells. Along with 5-LO-derived products, the biosynthesis of 15-LO-derived eicosanoids by HAM may also be relevant in modulating inflammatory responses in the lung.

Lipopolysaccharide primes human alveolar macrophages for enhanced release of superoxide anion and leukotriene B4: self-limitations of the priming response with protein synthesis

Human alveolar macrophages (AM) can produce potent reactive oxygen intermediates (ROI) and arachidonic acid metabolites (eicosanoids), which have important roles in host defense and the pathogenesis of some diseases of the lung. Bacterial lipopolysaccharide (LPS) is believed to cause profound lung injury and can prime mouse peritoneal macrophages for the enhanced secretion of ROI and eicosanoids. Therefore, we investigated the effect of LPS pretreatment on the ability of AM to release superoxide anions (O2-) and leukotriene B4 (LTB4). LPS can prime AM for the enhanced secretion of O2- and LTB4, regardless of whether they are derived from nonsmokers or smokers. Moreover, judging from the time-response characteristics, this priming for LTB4 release could be inhibited in the later stages of pretreatment, when the O2(-)-releasing capacity was enhanced. The priming inhibition was prevented, at least in part, by cycloheximide, but not by SOD and/or catalase. In addition, cycloheximide also inhibited the priming for O2- release. Hence, protein synthesis might be necessary for the priming for O2- release and for inhibiting the priming for LTB4 release. This phenomenon of self-limiting the priming response with LPS seems to be very important when we consider the high oxygen tension in the lungs and the many bacterial substances inspired into alveoli.

Effects of tobacco-smoke on radiation-induced pneumonitis in rats

To investigate the effect of exposure to tobacco smoke (TS) on the development of irradiation-induced pneumonitis in rats, five groups of animals were investigated including controls (C), tobacco smoke exposed (S), irradiated (RNS) and irradiated and tobacco smoke exposed (RS). An additional group (RS/NS) was exposed to tobacco before irradiation but not afterwards. Rats were exposed to diluted mainstream cigarette smoke at a concentration of about 0.4 mg/l in a nose-only exposure system for 1/day, 5 days/week for 10 weeks. Exposure to TS started 3 weeks before irradiation in which the basal one-third of both lungs was exposed to a single dose of 28 Gy. In previous studies this dose had been shown to cause significant pneumonitis. All the animals were killed at 7 weeks after irradiation. Examination of the morphology of lung sections showed less pulmonary inflammation in the RS group than in the RNS group. This was also reflected in the results of bronchoalveolar lavage (BAL) which showed a decline in cell recovery and a marked decrease in the numbers of mast cells and neutrophils in the RS rats compared with the RNS animals. The concentration of hyaluronan in lavage fluid was increased in the RNS and RS/NS group while no increase was found in the RS group. A marked increase in BAL protein was also seen in the RNS and RS/NS groups as compared with the RS group but all were significantly higher than in unirradiated controls. This indicates that smoking suppresses the radiation-induced inflammation but to a lesser degree affects the radiation-induced increase in membrane permeability as reflected by increased protein levels in BAL. Moreover, the marked effects on the numbers of mast cells and neutrophils in the RS group may indicate that these cells play an important role in the mechanism by which tobacco smoke modulates the effects of irradiation. When exposure to tobacco smoke was terminated immediately after irradiation (RS/NS), the inflammatory response was unaffected.

In vivo effect of lipopolysaccharide on alveolar and peritoneal macrophages of rats: superoxide anion generation and 5-lipoxygenase metabolism of arachidonic acid

Influences of the intravenous administration of Escherichia coli lipopolysaccharide, 3 mg/kg, on the production of superoxide anion (O2-) and 5-lipoxygenase metabolites of arachidonic acid (AA) were evaluated in alveolar macrophages (AM) and peritoneal macrophages (PM) on days 1 and 3 after injection. The dose selected was that found to induce a significant leakage of [125I]bovine serum albumin in the pulmonary vasculature. AM obtained 1 day after LPS injection generated smaller amounts of O2- on stimulation with C5a but generated similar amounts with wheat germ lectin (WGA) or AA compared with control AM. This result suggested a prior complement activation. On day 3, on the contrary, their production of O2- significantly exceeded that by control AM with either of the three stimuli. PM collected on day 1 after LPS injection generated a significantly greater amount of O2- on stimulation with either WGA or AA than did control PM. The amount of O2-, however, decreased from day 1 to day 3. AM collected 1 day after the injection of LPS generated significantly more leukotriene B4 (LTB4) and 5-HETE on stimulation with A23187 alone and in combination with AA than did the cells from untreated rats. Such activities returned to the control levels in the AM collected on day 3. In contrast, the PM collected on day 1 produced amounts of LTB4 and 5-HETE similar to those of the control PM, but the cells on day 3 produced significantly more LTB4.(ABSTRACT TRUNCATED AT 250 WORDS)

Leukotriene B4 level in stimulated blood neutrophils and alveolar macrophages from healthy and asthmatic subjects. Effect of beta-2 agonist therapy

Leukotriene B4 levels were measured after stimulation by calcium ionophore A23187: (i) in peripheral, neutrophils (PMN) from allergic asthmatics, rhinitis and healthy subjects; (ii) in macrophages collected by bronchoalveolar lavage. LTB4 levels in PMNs were significantly higher in non-treated allergic asthmatics and non-treated subjects with rhinitis compared to controls. Beta-2 agonist-treated asthmatics showed a significantly decreased LTB4 production which was not different from those of controls. In vitro, LTB4 production decreased significantly after PMN incubation with Salbutamol (10(-6) mol l-1). LTB4 produced by AM collected by BAL was measured in non-treated (n = 5) and treated (n = 11) asthmatics with inhaled beta-2 agonist. AM collected from all controls and non-treated asthmatics produced LTB4. By contrast, no production of LTB4 was observed in the treated group. LTB4 production decreased when normal AM were incubated in vitro with Salbutamol (10(-8) mol l-1). These results suggest that biochemical differences occur in PMN and macrophages from subjects treated with beta-2 agonist, presumably in changing the 5-lipoxygenase pathway.

Alteration of platelet activating factor (PAF) metabolism in rat pulmonary alveolar macrophages and plasma by cigarette smoking

The pathophysiological role of platelet activating factor (PAF) in smoking-induced disorders was examined in rats exposed daily to smoke for 10, 18 and 26 weeks. The concentration of PAF in bronchoalveolar lavage fluid and the activities of PAF biosynthetic and catabolic enzymes in alveolar macrophages and in plasma were determined. The concentration of PAF in lavage fluid of the smoke-exposed group was significantly lower than that in the sham group for each duration of smoke exposure. The PAF biosynthetic enzyme, acetyl transferase, activity in alveolar macrophages of smoked group was less than that in the sham group although the difference was not statistically significant. PAF catabolic enzyme, acetyl hydrolase, activities in alveolar macrophages and in plasma were all significantly higher in every smoked group than in the sham group. These data indicate that cigarette smoking alters PAF metabolism in the respiratory tract and in plasma and such an alteration may contribute, at least in part, to smoking induced cardiopulmonary disorders.

Cigarette smoking reduces human salivary eicosanoids

The effect of cigarette smoking on salivary eicosanoid levels was investigated in 10 smoker and 10 non-smoker volunteers. The smokers consumed an average of 20 cigarettes/day for the past 5 years or longer. The smoking status was validated by salivary cotinine level. Eicosanoids were extracted from saliva with ethanol, and the radioimmunoassay was performed to determine the concentrations of four major eicosanoids, i.e. prostaglandin E2 (PGE2), PGF2 alpha, 6-sulphidopeptide-containing leukotrienes (LTs) and 12-hydroxyeicosatetraenoic acid (12-HETE). The levels of PGE2, PGF2 alpha, and LTs were significantly lower in the saliva of smokers as compared to that of the non-smokers (1.74 +/- 0.32 vs 2.41 +/- 0.64, p = 0.006; 0.36 +/- 0.12 vs 0.54 +/- 0.18, p = 0.04; 2.24 +/- 0.96 vs 4.92 +/- 1.29, p = 0.006; mean +/- SD, ng/ml saliva). No significant differences were found in the levels of 12-HETE between the two groups. The results suggest that cigarette smoking reduces the concentrations of both the cyclooxygenase and 5-lipoxygenase products in saliva.

Enhanced esterification process of 5-hydroxyeicosatetraenoic acid (5-HETE) in PMN from asthmatic patients

Polymorphonuclear neutrophils (PMN) generate 5-HETE which can be retained within cells as free metabolites or esterified into cellular lipids. Since this metabolite has been shown to have certain inflammatory properties, we compared the generation and distribution profile of 5-HETE in A 23187-stimulated PMN from asthmatic patients (AP) and normal subjects (NS). 5-HETE was analyzed using RP-HPLC. After 5 min, total 5 HETE generation was similar in the two populations. However, esterified 5-HETE was significantly enhanced in AP (72 +/- 3% versus 47 +/- 2% of the total synthesis, p less than 0.005), whereas intracellular free 5-HETE was decreased (13 +/- 3% versus 37 +/- 4%, p less than 0.005) and similar low release was observed. Kinetic studies showed that PMN from AP esterified 5-HETE more rapidly and to a greater extent than PMN from NS. By contrast, more intracellular free 5-HETE was recovered in PMN from NS. Esterification seems to be the major pathway of 5-HETE metabolism in PMN from AP. Moreover, we showed that most of the 5-HETE added exogenously was esterified into cellular lipids. In these experimental conditions, PAF-induced migration of PMN was increased. The enhanced ability of PMN to migrate could be due to the increase of 5-HETE esterification process.

Eicosanoid levels in bronchoalveolar lavage fluid of young female smokers and non-smokers

To evaluate indicators of inflammatory changes in the airways of young smokers we have measured the levels of several eicosanoids in bronchoalveolar lavage (BAL) fluid of 18 female smokers (age 33 +/- 2 years) and 9 female non-smokers (age 29 +/- 2 years) who were hospitalized for treatment not related to any pulmonary disease. In each BAL specimen the following eicosanoids were determined by radioimmunoassay: prostaglandin (PG) E2; PGF2 alpha; 9 alpha, 11 beta-PGF2, a metabolite of PGD2; 6-keto PGF1 alpha, a metabolite of prostacyclin; thromboxane (Tx) B2, a metabolite of TxA2; the 5-lipoxygenase products 5-hydroxy-eicosa-tetraenoic acid (HETE), leukotriene (LT) B4 and LTC4; the 12-lipoxygenase product 12-HETE; and the 15-lipoxygenase product 15-HETE. The concentrations of the cyclooxygenase products (pg ml-1) in the BAL fluid of the non-smokers were: PGE2 15.4 +/- 1.9, PGF2 alpha 7.6 +/- 1.0, 9 alpha, 11 beta-PGF2 8.7 +/- 1.8, TxB2 8.8 +/- 1.3, and 6-keto PGF1 alpha only 1.5 +/- 0.8. The concentration of the lipoxygenase products were: 15-HETE 781 +/- 200, 12-HETE 193 +/- 33, 5-HETE 14.0 +/- 3.1, LTC4 9.5 +/- 3.1, LTB4 6.2 +/- 1.4. BAL fluid from smokers contained two- to three-fold higher levels of TxB2 and PGF2 alpha (P less than 0.05). The levels of TxB2 and PGF2 alpha were positively correlated to the number of package years (rs = 0.55 and rs = 0.65, P less than 0.02). The concentrations of 5-, 12- and 15-HETE tended to be higher in BAL fluid from smokers, but this was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma, inflammation, eosinophils and bronchial hyperresponsiveness

Asthmatics can have a blood eosinophilia which in some studies correlates with the severity of the disease. However, an increased number and percentage of activated eosinophils can be present in the blood without asthma. The eosinophils that contribute to asthma will be those in the lung. In the BAL fluids collected from asthmatics there is usually no change in total cell number, but there are changes in the differential cell count. A consistent finding is an increase in percentage of mast cells and eosinophils with a tendency for an increase in lymphocytes and epithelial cells and a decrease in percentage of macrophages. As with the blood eosinophilia, an increase in number of eosinophils can be present in BAL fluids without asthma. The site of localization and activation of the eosinophils in the lung may be critical. In bronchial biopsies, taken from asthmatics, increased number of mast cells, eosinophils and lymphocytes have been demonstrated in the bronchial mucosa together with shedding of columnar epithelial cells. However these changes have not been found, or have not reached significance, in all studies. An increase in number of activated eosinophils and T-lymphocytes has been demonstrated but an increase in number of degranulating mast cells has been disputed. A consistent finding has been thickening below the basement membrane. Attempts to correlate the changes in the BAL or lung biopsies with the severity of asthma, lung airways function or bronchial responsiveness have given inconsistent results. Treatment of asthmatics with inhaled steroids can reduce the cellular infiltration in the bronchial biopsies to normal levels but this produces a trivial reduction in bronchial responsiveness. It is possible that infiltration of inflammatory cells into the bronchial mucosa is intermittent, at least in mild asthma, but this produces changes leading to a long lasting bronchial hyperresponsiveness.

Time-dependent alterations of leukotriene production and catabolism in rat peritoneal macrophages following intraperitoneal injection of thioglycollate broth

Alterations of leukotriene (LT) productivity in peritoneal macrophages (PM) from untreated rats (control) as well as from rats treated i.p. with thioglycollate broth (TG) were investigated on days 3, 7 and 14 after TG administration. The resident PM from the untreated rats produced mainly LTB4 and 5-HETE with small amounts of 12-HETE and LTD4 with only a trace of LTC4 when stimulated with the calcium ionophore A23187. The PM elicited from rats on days 3 and 7 produced more LTC4 than did the resident PM but fewer other lipoxygenase metabolites. On day 14, however, the elicited PM resembled the resident PM in terms of lipoxygenase metabolite production. Similar results were achieved in the presence of arachidonic acid and A23187. A decrease in lipoxygenase metabolism in the elicited PM was also suggested by using opsonized zymosan. Catabolism studies indicated a reduction in r-glutamyl transpeptidase activity in the elicited PM and suggested a reduction in catabolism for LTB4 in the former cells. The authors conclude that the TG-elicited PM generate fewer lipoxygenase metabolites than the resident PM following stimulation, but show a preferential conversion of LTA4 to sulfidopeptide LTs rather than to LTB4. The elicited PM also show a reduced catabolism for LTC4 and LTB4.

Leukotriene B4 and Kawasaki disease

The role of LTB4 in Kawasaki disease as a chemo-attractant and immunomodulator is reviewed through our own experience and reports by other investigators. In our experiment using 19 patients, we measured calcium ionophore-stimulated LTB4 synthesis in PMNs obtained in three different stages of the illness (acute, convalescent and recovered phases). LTB4 synthesis was significantly increased in the convalescent phase of the illness. Other investigators showed increased serum-LTB4 concentration in acute as well as convalescent phases, suggesting that LTB4 participated in the inflammatory process of Kawasaki disease as an inflammatory mediator and immunomodulator. However, no difference was found in LTB4 synthetic activity in PMNs in any phases of the illness between the patients with and without coronary lesions, which indicated that LTB4 was not a parameter of coronary aneurysm formation. Therapeutic use of high-dose gamma-globulin showed a tendency to decreased LTB4 synthesis in PMNs, although it is not conclusive.

Smoking, humoral immunity, and ulcerative colitis

Since ulcerative colitis predominantly affects non-smokers and ex-smokers we have examined the possibility that smoking modifies the humoral immune response to an antigenic challenge from the gut lumen. Gut lavage was used in healthy subjects and patients with ulcerative colitis, including both smokers and non-smokers. Antibodies in the intestinal fluid to Escherichia coli (five pooled serotypes), Candida albicans, gliadin, ovalbumin, and beta lactoglobulin were measured by ELISA to determine specific antibody concentrations of IgG, IgA, and IgM classes. Total IgG, IgA, and IgM were also measured in intestinal secretions and serum. In addition, circulating antibody concentrations of IgG, IgA, and IgM to three gut commensals - E coli (five pooled serotypes) C albicans, and Poroteus mirabilis were measured. There was a significant reduction in the IgA concentration in intestinal fluid of smokers with ulcerative colitis compared with healthy non-smoking controls. No other significant differences were found between the groups. Overall, these data are not consistent with the idea that smoking suppresses immune responses in the gut and suggest that the effect of smoking in colitis is mediated by another mechanism.

Neutrophil accumulation in the lung in alpha 1-antitrypsin deficiency. Spontaneous release of leukotriene B4 by alveolar macrophages

The emphysema of alpha 1-antitrypsin (alpha 1AT) deficiency is conceptualized to result from insufficient alpha 1AT allowing neutrophil elastase to destroy lung parenchyma. In addition to the deficiency of alpha 1AT in these individuals resulting from mutations in the alpha 1AT gene, it is recognized that, for unknown reasons, there are also increased numbers of neutrophils in their lungs compared with normal individuals. With the knowledge that alveolar macrophages have surface receptors for neutrophil elastase, we hypothesized that the neutrophil accumulation in the lower respiratory tract in alpha 1AT deficiency may result, in part, from release of neutrophil chemotactic activity by alveolar macrophages as they bind uninhibited neutrophil elastase. Consistent with this hypothesis, alpha 1AT-deficient alveolar macrophages spontaneously released nearly threefold more neutrophil chemotactic activity than normal alveolar macrophages. Analysis of alpha 1AT-deficient macrophage supernates by reverse-phase HPLC, molecular sieve chromatography, radioimmunoassay, and absorption with anti-LTB4 antibody revealed that the majority of the chemotactic activity was leukotriene B4 (LTB4), a mediator absent from normal macrophage supernates. Consistent with this hypothesis, incubation of normal macrophages with human neutrophil elastase resulted in the release of the same neutrophil chemotactic mediator. Furthermore, purified human alpha 1AT was able to prevent the neutrophil elastase from stimulating the macrophages to release the chemotactic factor. Together, these findings suggest that the absence of a normal antineutrophil elastase screen in the lower respiratory tract permits free neutrophil elastase to bind to alveolar macrophages, resulting in the release of LTB4, a process which attracts neutrophils to the alveoli of alpha 1AT deficient individuals, thus accelerating the lung destruction that characterizes this disorder.

Macrophages cultured in vitro release leukotriene B4 and neutrophil attractant/activation protein (interleukin 8) sequentially in response to stimulation with lipopolysaccharide and zymosan

The capacity of lipopolysaccharide (LPS), zymosan, and calcium ionophore A23187 to induce neutrophil chemotactic activity (NCA), leukotriene B4 (LTB4), and neutrophil attractant/activation protein (NAP-1) release from human alveolar macrophages (AM) retrieved from normal nonsmokers was evaluated. LPS induced a dose-dependent release of LTB4 that began by 1 h, 4.0 +/- 3.2 ng/10(6) viable AM; peaked at 3 h, 24.7 +/- 13.5 ng/10(6) viable AM; and decreased by 24 h, 1.2 +/- 1.0 ng/10(6) viable AM (n = 8). Quantities of LTB4 in cell-free supernatants of AM stimulated with LPS were determined by reverse-phase high-performance liquid chromatography and corresponded well with results obtained by radioimmunoassay. By contrast, NAP-1 release began approximately 3-5 h after stimulation of AM with LPS, 197 +/- 192 ng/ml, and peaked at 24 h, 790 +/- 124 ng/ml. Release of NAP-1 was stimulus specific because A23187 evoked the release of LTB4 but not NAP-1, whereas LPS and zymosan induced the release of both LTB4 and NAP-1. The appearance of neutrophil chemotactic activity in supernatants of AM challenged with LPS for 3 h could be explained completely by the quantities of LTB4 present. After stimulation with LPS or zymosan for 24 h, AM had metabolized almost all generated LTB4. Preincubation of AM with nordihydroguiaretic acid (10(-4) M) completely abolished the appearance of NCA, LTB4, and NAP-1 in supernatants of AM challenged with LPS. Therefore, LPS and zymosan particles were potent stimuli of the sequential release of LTB4 and NAP-1 from AM.

Enhanced leukotriene C4 synthase activity in thioglycollate-elicited peritoneal macrophages

The utilization of LTA4 by peritoneal macrophages (MO) obtained from untreated rats (control) as well as by those elicited from rats was investigated at designated intervals (on days 3, 7, and 14) following the intraperitoneal injection of thioglycollate (TG). On day 7 following the injection the elicited MO converted LTA4 to LTC4 at the highest rate while the resident MO showed the lowest rate. The conversion of LTA4 to LTC4 and LTB4 was next examined by using each MO lysate. The apparent LTC4 synthase activity was significantly higher in the MO lysate both on day 3 and day 7, with the latter being the highest value obtained. The GSH S-transferase activity in each lysate using as the substrate, DNCB was significantly lower on day 3 but significantly higher on day 7 as compared to control values. However, this elevated activity was less variable than that observed with LTC4 synthase. The possible implication for these observations is discussed.

Chemoattractant and leukotriene B4 production from rat alveolar macrophages exposed to nitrogen dioxide

The present study examined the hypothesis that exposure of alveolar macrophages to nitrogen dioxide (NO2) resulted in enhanced production of a lipophilic chemotactic agent for neutrophils, possibly leukotriene B4 (LTB4). Neutrophil migration was significantly increased in response to the reconstituted ethyl acetate extract of the medium surrounding macrophages exposed for 1 h to 5 or 20 ppm NO2. Compared with air-treated macrophages, production of LTB4 was found to be significantly increased by exposure to 5 ppm NO2, but unchanged by exposure to 20 ppm NO2. Treatment of macrophages with the calcium ionophore A23187 at a concentration of 2 microM for 15 min following a 1-h exposure to 5 ppm NO2 led to a significant increase in the production of LTB4 compared with A23187-treated air controls; however, LTB4 production in response to the calcium ionophore was unchanged following exposure to 20 ppm NO2. Thus, while increased neutrophil migration in response to products from macrophages exposed to 5 ppm NO2 correlated with the increased production of LTB4, increased migration in response to products from macrophages exposed to 20 ppm NO2 suggested the presence of another chemotactic lipid. Lipid peroxidation processes induced by NO2 at 5 ppm may lead to the formation of hydroperoxides that enhance the formation of LTB4; yet at 20 ppm, significantly higher concentrations of hydroperoxides may be responsible for impaired LTB4 formation. Phorbol ester-stimulated macrophage superoxide production was significantly inhibited in a dose-dependent manner following exposure to NO2 concentrations of 1, 5, or 20 ppm.

Transfer of 99mTc DTPA and bronchoalveolar lavage findings in patients with asymptomatic extrinsic allergic alveolitis

An investigation was performed to determine whether symptom free patients with previously diagnosed extrinsic allergic alveolitis had signs of inflammation in the lung. Pulmonary clearance of inhaled technetium-99m labelled diethylene triamine penta-acetic acid (DTPA) was measured in seven patients with a history of extrinsic allergic alveolitis but with no symptoms at the time of the study and in 12 control subjects. Monoexponential clearance curves were obtained in all 12 control subjects. In contrast, lung clearance was abnormal in five of the seven patients: biexponential clearance curves were noted in four and an abnormally rapid monoexponential curve in one. Bronchoalveolar lavage was performed in all patients. Fluid from the second and third aliquots showed increased concentrations of albumin and urea in fluids from the patients, suggesting increased plasma leakage through the alveolocapillary membranes. More eosinophils and more eosinophil cationic protein were also found in the lavage fluid from the patients. The trend towards increased numbers of eosinophils in patients with abnormal lung clearance of DTPA suggests that this may be due to a continuing inflammatory reaction. Lung inflammation was also suggested by the fact that less leukotriene B4 was secreted by cultured alveolar macrophages obtained from patients than by control macrophages. It is concluded that symptom free patients with previous extrinsic allergic alveolitis have continuing alveolar disease as shown by lung clearance and lavage findings.

Inhibition of production of LTB4 and chemotactic agent from rat alveolar macrophages treated with t-butyl hydroperoxide is independent of ATP depletion

In rat alveolar macrophages treated with 100 microM t-butyl hydroperoxide (tBOOH), leukotriene B4 (LTB4) synthesis was significantly lower than the basal level while levels of cyclooxygenase pathway products were increased. LTB4, 5,6-dihydroxyeicosatetraenoic acid (5,6-DiHETEs), and 5-hydroxyeicosatetraenoic acid (5-HETE) production in macrophages was significantly stimulated by 2 microM A23187, but this was suppressed 40% by simultaneous addition of 10 microM tBOOH and completely abolished by 100 microM tBOOH. Basal and A23187-stimulated macrophage production of chemotactic agents were similarly suppressed by addition of tBOOH; this effect paralleled depression of cellular LTB4 synthesis. In contrast to the significant depression of A23187-stimulated formation of 5-lipoxygenase products by 10 microM tBOOH, cellular adenosine triphosphate (ATP) was unchanged. Macrophages pretreated with KCN led to a 42% decline in ATP levels; however, LTB4, 5,6-DiHETEs, and 5-HETE production in response to A23187 was not suppressed. The results indicate that inhibition of 5-lipoxygenase pathway products in macrophages treated with tBOOH did not occur by depletion of cellular ATP levels.

Enhanced superoxide anion generation but reduced leukotriene B4 productivity in thioglycollate-elicited peritoneal macrophages

Lipoxygenase metabolism of arachidonic acid was compared between peritoneal macrophages from untreated rats and those from rats on day 7 after intraperitoneal injection of thioglycollate broth (TG). Resident macrophages (M phi) from untreated rats produced mainly LTB4 (303 +/- 25 pmol/5 x 10(6) cells) and 5-HETE (431 +/- 56 pmol/5 x 10(6) cells) when stimulated with 5 micrograms/ml calcium ionophore A23187 for 20 min at 37 degrees C. On the other hand, TG-elicited M phi generated less amounts of lipoxygenase metabolites (157 +/- 10 pmol LTB4 and 319 +/- 19 pmol 5-HETE/5 x 10(6) cells) with the same stimulus. Then, leukotriene productivity was examined by using subcellular fractions of each M phi lysate and an unstable epoxide intermediate, leukotriene A4. LTA4 hydrolase activity was mainly contained in soluble fractions from the both groups of M phi. The cytosol fraction from the resident M phi exhibited the following specific and total activity; 2.2 +/- 0.1 nmol LTB4/mg protein/5 min and 12.2 +/- 0.5 nmol LTB4/5 min per 10(8) cells. On the contrary, the cytosol fraction from the TG-elicited M phi showed 1.9 +/- 0.1 nmol LTB4/mg protein/5 min and 9.6 +/- 0.3 nmol LTB4/5 min per 10(8) cells. The resident M phi, however, generated 0.14 +/- 0.04 nmol O2-/min/4 x 10(5) cells whereas the TG-elicited M phi did 0.49 +/- 0.13 nmol O2-/min/4 x 10(5) cells when stimulated with wheat germ lectin. These results suggest that the TG-elicited macrophages show enhanced superoxide production but generate less lipoxygenase metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of an inhaled corticosteroid, budesonide, on alveolar macrophage function in smokers

Selected functions of alveolar macrophages obtained by bronchoalveolar lavage of 12 healthy smokers were examined before and after eight weeks' treatment with an inhaled glucocorticosteroid, budesonide (400 micrograms twice daily). After budesonide treatment spontaneous as well as opsonised zymosan triggered prostaglandin E2 (PGE2) secretion from harvested cells was reduced; no such reduction in opsonised zymosan triggered leukotriene B4 (LTB4) production was observed. Neither the capacity to phagocytose opsonised yeast particles nor the superoxide radical generation triggered by the calcium ionophore A23187, 4 beta-phorbol 12-myristate 13-acetate (PMA), or opsonised zymosan ex vivo were more than marginally affected by the glucocorticosteroid treatment in vivo. Lavage fluid concentrations of angiotensin converting enzyme (ACE), however, after treatment were twice those before treatment and concentrations of fibronectin were reduced to half. Albumin concentrations in lavage fluid were not affected by the glucocorticosteroid treatment. In separate experiments treatment of alveolar macrophages with 10(-7) or 10(-6) M budesonide overnight in vitro did not affect their superoxide radical or PGE2 generation but significantly blocked LTB4 release. These data indicate that inhaled gluco-corticosteroid treatment may affect synthesis or release (or both) of ACE and fibronectin by alveolar macrophages from healthy smokers whereas other functions of these cells, such as the generation of reactive oxygen derived products ex vivo, are only marginally affected.

Inhibitory effects of MK-886 on arachidonic acid metabolism in human phagocytes

1. We have investigated the inhibitory activity of compound MK-886 (formerly L-663,536), an indole derivative, on 5-lipoxygenase product synthesis in various human phagocytes stimulated with either the ionophore A23187, in the presence and absence of exogenous arachidonic acid, or platelet-activating factor (PAF). The lipoxygenase products were analysed by reversed-phase h.p.l.c. 2. MK-886 inhibited the formation of 5-hydroxy-eicosatetraenoic acid (5-HETE), leukotriene B4 (LTB4), its omega-oxidation products and 6-trans-isomers with an IC50 value of 10-14 nM in A23187-stimulated neutrophils. In the same system, nordihydroguaiaretic acid (NDGA), AA-861 and L-655,240 showed IC50 values of 250-510, 110-420 nM and 1.7-3.9 microM, respectively. 3. MK-886 inhibited 5-lipoxygenase product synthesis in A23187-stimulated blood eosinophils and monocytes, and in neutrophils primed with granulocyte-macrophage colony-stimulating factor and stimulated with PAF with IC50 values of 1-13 nM. 4. The inhibitory activity of MK-886 was not reversed by addition of 10 microM arachidonic acid to A23187-stimulated neutrophils. 5. Compound MK-886 had no effect on 15-lipoxygenase product synthesis in blood eosinophils and neutrophils up to a concentration of 1 microM. 6. At 100 nM compound MK-886 had no significant effects on calcium ion mobilization, superoxide anion production and actin polymerization in neutrophils. 7. In conclusion, MK-886 is a very potent and specific inhibitor of both LTB4 and LTC4 synthesis in various types of human phagocytes.