Enhanced cytotoxic potential of alveolar macrophages from cigarette smokers

Cigarette smoking increases the numbers and oxidative metabolism of alveolar macrophages. Increased production of superoxide (O2-) and H2O2 by alveolar macrophages may contribute to the pathogenesis of cigarette-induced lung diseases. The cytotoxicity mediated by alveolar macrophages from smokers (n = 11) and nonsmokers (n = 13) was compared in an in vitro assay in which the target cells were chromium 51-labeled lung explants. The spontaneous cellular cytotoxicity mediated by smoker macrophages was significantly greater than that of nonsmoker macrophages (cytotoxic index 20.3% +/- 1.9% compared with 5.5% +/- 0.9%, P less than 0.001). Phorbol myristate acetate significantly increased the cytotoxic index of nonsmoker macrophages but did not cause further increases in smoker macrophage killing. The antioxidants superoxide dismutase and catalase produced partial inhibition of smoker macrophage cytotoxicity, suggesting that target cell killing was mediated in part by oxidant mechanisms. Supplementation of smokers' diets with high-dose oral vitamin E failed to decrease smoker alveolar macrophage cytotoxicity. These findings demonstrate that smoker alveolar macrophages possess enhanced cytotoxic potential for normal lung parenchymal cells.     

Decreased ceruloplasmin ferroxidase activity in cigarette smokers

Ceruloplasmin is one of the most important antioxidant proteins in serum. Ceruloplasmin functions as a ferroxidase that oxidizes iron to the Fe3+ state, thereby preventing Fe2+-catalyzed lipid peroxidation and cellular damage. Despite increased antigenic amounts of ceruloplasmin, cigarette smoker serum has previously been shown to exhibit significantly less antioxidant activity than non-smoker serum. We demonstrate that the decreased antioxidant activity of cigarette smoker serum may be explained by a decrease in ceruloplasmin ferroxidase activity. Smokers had a 14% decrease in serum ceruloplasmin ferroxidase activity (units per milliliter) compared with nonsmokers. There was a 24% decrease in ferroxidase activity per milligram of ceruloplasmin in smokers compared with nonsmokers (0.32 +/- 0.009 U/mg vs 0.42 +/- 0.020 U/mg, p less than 0.005). Smoker serum also contained significantly less ceruloplasmin-specific antioxidant activity than nonsmoker serum. These observations may explain the decrement in smoker serum antioxidant activity that could predispose cigarette smokers to increased oxidant injury.     

Risk factors for emphysema. Cigarette smoking is associated with a reduction in the association rate constant of lung alpha 1-antitrypsin for neutrophil elastase.

The increased risk of developing emphysema among individuals who smoke cigarettes and who have normal levels of alpha 1-antitrypsin (alpha 1AT) is hypothesized to result from a decrease in the antineutrophil elastase capacity of the lower respiratory tract alpha 1AT of smokers compared with nonsmokers. To evaluate this hypothesis we compared the time-dependent kinetics of the inhibition of neutrophil elastase by lung alpha 1AT from healthy, young cigarette smokers (n = 8) and nonsmokers (n = 12). alpha 1-antitrypsin was purified from lavage fluid using affinity and molecular sieve chromatography, and the association rate constant (k assoc) for neutrophil elastase quantified. The k assoc of smoker plasma alpha 1AT (9.5 +/- 0.5 X 10(6) M-1s-1) was similar to that of nonsmoker plasma (9.3 +/- 0.7 X 10(6) M-1s-1, P greater than 0.5). In marked contrast, the k assoc of smoker lower respiratory tract alpha 1AT was significantly lower than that of nonsmoker alpha 1AT (6.5 +/- 0.4 X 10(6) M-1s-1 vs. 8.1 +/- 0.5 X 10(6) M-1s-1, P less than 0.01). Furthermore, the smoker lower respiratory tract alpha 1AT k assoc was significantly less than that of autologous plasma (P less than 0.01). When considered in the context of the concentration of alpha 1AT in the lower respiratory tract epithelial lining fluid, the inhibition time for neutrophil elastase of smoker lung alpha 1AT was twofold greater than that of nonsmoker lung alpha 1AT (smoker: 0.34 +/- 0.05 s vs. nonsmoker: 0.17 +/- 0.05 s, P less than 0.01). Consequently, for concentrations of alpha 1AT in the lower respiratory tract it takes twice as long for an equivalent amount of neutrophil elastase to be inhibited in the smoker's lung compared with the nonsmoker's lung. These observations support the concept that cigarette smoking is associated with a decrease in the lower respiratory tract neutrophil elastase inhibitory capacity, thus increasing the vulnerability of the lung to elastolytic destruction and thereby increasing the risk for the development of emphysema.     

Multiple defects in arachidonate metabolism in alveolar macrophages from young asymptomatic smokers

This study was undertaken to localize and determine the relative importance of potential biochemical defects in the release and metabolism of arachidonic acid (AA) in alveolar macrophages (AMs) from asymptomatic smokers. Using high-performance liquid chromatography and radioimmunoassay, we compared the metabolism of both endogenously released and exogenously supplied AA in AMs and autologous peripheral blood monocytes (PBMs) from nine healthy nonsmokers and eight healthy smokers. AMs from both groups incorporated similar amounts of radiolabeled AA into cellular lipids. However, AMs from smokers released only about half as much radioactivity as free AA and its metabolites in response to ionophore A23187, when compared to cells from nonsmokers; this suggests that net phospholipase activity was decreased in smokers. In addition, AMs from smokers synthesized less of total cyclooxygenase and 5-lipoxygenase products than did cells from nonsmokers, both constitutively and in response to A23187 as well as the particulate agonist zymosan. Furthermore the metabolism of exogenous AA to both cyclooxygenase and 5-lipoxygenase products was reduced in smoker cells compared to nonsmoker cells. Inverse relationships between eicosanoid synthesis and intensity of smoking were observed. No differences between smoker and nonsmoker PBMs were found. These results show that the major defect in smoker AMs is at the phospholipase level, with additional defects being present at the levels of the cyclooxygenase and 5-lipoxygenase pathways. All these abnormalities are compartmentalized to the mononuclear phagocyte population of the lung.     

Ascorbic acid content and accumulation by alveolar macrophages from cigarette smokers and nonsmokers

The lung is at risk for injury from inhaled oxidants, including components of cigarette smoke; therefore, maintaining a chemical antioxidant defense would be advantageous. The potential for ascorbic acid to assume this protective role was investigated by comparing the total ascorbate content of alveolar macrophages obtained from human smokers and nonsmokers, from hamsters that were exposed to cigarette smoke for 4 to 6 weeks, and from a control group of unexposed hamsters. The abilities of alveolar macrophages from these four sources to accumulate 14C-labeled ascorbic acid and dehydroascorbate were also compared. The total ascorbate content in hamster macrophages was 19.5 +/- 1.7 and 44.3 +/- 2.8 nmol/10(7) cells for nonsmokers and smokers, (n = 5) and 73.8 +/- 13.1 nmol/10(7) cells (n = 13, p less than 0.1) for nonsmokers and smokers, respectively. In both humans and hamsters, the rates of accumulation of ascorbic acid and dehydroascorbate were significantly greater (p less than 0.05) for alveolar macrophages from smokers compared with nonsmokers of the same species. After internalization, greater than or equal to 70% of the dehydroascorbate was reduced to ascorbic acid by alveolar macrophages from nonsmokers and smokers of both species. An aqueous extract of cigarette smoke oxidized significantly more ascorbic acid to dehydroascorbate in vitro than a comparable volume of phosphate-buffered saline solution without smoke. The increased content of total ascorbate in alveolar macrophages from smokers and their enhanced ability to accumulate ascorbic acid and dehydroascorbate in vitro may reflect protective utilization of ascorbic acid under conditions of increased oxidant stress, compared with nonsmokers. In addition, alveolar macrophages may internalize dehydroascorbate that has been generated by oxidants in the alveolar space and reduce it to ascorbic acid so it can be reused as an antioxidant.     

Specificity of opsonic antibodies to enhance phagocytosis of Pseudomonas aeruginosa by human alveolar macrophages.

These studies compared the ability of specific secretory IgA (sIgA) and IgG antibodies to promote phagocytosis of viable pseudomonas aeruginosa by human alveolar macrophages. Macrophages were obtained by lung lavage of normal adult smoker and nonsmoker volunteers and were maintained as in vitro cell monolayers. Both immune sIgA and IgG agglutinating antibodies were demonstrated to coat and opsonize viable bacteria, whereas similar nonimmune immunoglobulin preparations did not. When alveolar macrophages were challenged with viable opsonized 14C-labeled Pseudomonas IgG-reacted bacteria were ingested better and killed more readily than sIgA-opsonized organisms. Phagocytic responses were not significantly different between macrophages obtained from smokers and nonsmokers. Although sIgA and IgG antibodies can be found in respiratory secretions and both are undoubtedly important in pulmonary host defense, IgG opsonic antibody was superior in enhancing the uptake of Pseudomonas by in vitro-cultured alveolar macrophages. It may be the more important respiratory antibody for certain bacterial infections.     

Decreased leukotriene B4 synthesis in smokers' alveolar macrophages in vitro

Recent studies have shown that alveolar macrophages (AM) are able to release leukotrienes (LTs). Since cigarette smoking inhibits the cyclooxygenase pathway of arachidonic acid metabolism in the AM, we evaluated the LT production by AM from smokers and nonsmokers. AM were obtained from 35 volunteers, 16 nonsmokers, and 19 smokers. The cells were incubated under various conditions including stimulation with 30 microM arachidonic acid, 2 microM ionophore A23187, or both. Each experiment was performed in parallel using cells from a smoker and a nonsmoker. Lipoxygenase products were analyzed by reverse-phase high performance liquid chromatography. After stimulation, nonsmokers' AM produced LTB4 and 5-hydroxy-eicosatetraenoic acid (5-HETE). In incubations of AM with arachidonic acid and ionophore, the amounts of products formed were: LTB4, 317 +/- 56 pmol/10(6) cells and 5-HETE, 1,079 +/- 254, mean +/- SEM. No metabolites were generated under control conditions (no stimulation). In all incubations performed, the peptido-LTs (LTC4, LTD4, and LTE4) were undetectable. In comparison with AM from nonsmokers, those from smokers showed a 80-90% reduction of 5-HETE and LTB4 synthesis (P less than 0.05 to P less than 0.001 according to stimulatory conditions). This defective lipoxygenase metabolite production in AM from smokers was observed over a wide range of stimuli concentrations and incubation times; AM from smokers also had lower levels of intracellular (esterified) 5-HETE than nonsmokers' AM. We also studied blood polymorphonuclear leukocytes (PMNL) and no difference in the synthesis of 5-lipoxygenase products in these cells was noticed between smokers and nonsmokers. These data show that cigarette smoking causes a profound inhibition of the 5-lipoxygenase pathway in AM but not in blood PMNL.     

Alpha-1-antitrypsin content in the serum, alveolar macrophages, and alveolar lavage fluid of smoking and nonsmoking normal subjects.

The content of alpha-1-antitrypsin in the serum, alveolar lavage fluid, and alveolar macrophages of smokers and nonsmokers was studied. Bronchoalveolar lavage was used to obtain alveolar fluid and macrophages from normal volunteers, and alpha-1-antitrypsin and albumin were measured using the electroimmunodiffusion technique. The serum level of inhibitor was not different between the two groups, while the total lavage fliud content of alpha-1-antitrypsin was increased in the smokers. The level of alpha-1-antitrypsin was also significantly greater (P less than 0.001) in the alveolar macrophages of the smokers suggesting the possibility of chronically increased alveolar levels in the cigarette smoker as a possible protective mechanism against proteolysis.     

The effect of smoking on bone metabolism: maternal and cord blood bone marker levels

BACKGROUND: To clarify the effect of smoking on bone metabolism in the fetus, we measured osteocalcin (OC), bone isoenzyme of alkaline phosphatase (BALP), procollagen type 1 C-terminal propeptide (PICP) in maternal serum and umbilical cord blood. METHODS: 15 active smoker, 14 passive smoker, 15 nonsmoker women and their newborn were included in this study. OC, BALP, PICP were determined by enzyme immunoassay. RESULTS: Of the bone markers tested only OC was different in the serum of the three groups of women. Infants of smoker women have significantly lower umbilical cord blood OC levels than those of infants from both passive smoker and nonsmoker women.(25.6 +/- 6.6, 35.8 +/- 10.4, 37.2 +/- 16.1 ng/mL respectively, p < 0.05). Infants of smoker women have significantly lower umbilical cord blood BALP levels than those of infants from nonsmoker women. (46 +/- 12, 57 +/- 15 U/L p < 0.05). All bone markers except total ALP were significantly higher in umbilical cord blood as compared to maternal blood levels (p < 0.001 for all). CONCLUSION: High umbilical cord blood bone marker levels may reflect the altered bone metabolism of fetus. Moreover, chronic hypoxia due to smoking may cause the suppression of bone matrix synthesis or placental synthesis as reflected by low OC and BALP levels in umbilical cord blood of infants from smoker women.     

Spontaneous hydrogen peroxide release from alveolar macrophages of some cigarette smokers

Alveolar macrophages were retrieved by bronchoalveolar lavage (BAL) from 30 patients, 24 smokers and six nonsmokers. The macrophages were separated from other cells in the BAL fluid by glass adherence. The amount of hydrogen peroxide released into the media by these macrophages was then measured by a new method of determining hydrogen peroxide concentration. Two groups were found. Group 1, who did not spontaneously release hydrogen peroxide, were mostly nonsmokers (six of nine), and group 2, who spontaneously secreted hydrogen peroxide (87.5 +/- 17.08 nmol/10(6) macrophages [mean +/- SEM]), were all smokers (21 of 21). When the alveolar macrophages in group 1 were stimulated with phorbol myristate acetate, they secreted as much hydrogen peroxide as the stimulated macrophages of group 2 (group 1: 125.0 +/- 92.08 nmol/10(6) macrophages, group 2: 116.7 +/- 14.82 nmol/10(6) macrophages). We conclude that there is a subset of smokers whose alveolar macrophages spontaneously release hydrogen peroxide.     

Iron binding, internalization, and fate in human alveolar macrophages

Chronic inflammation in such diseases as rheumatoid arthritis has been associated with the accumulation of iron in mononuclear phagocytes. Cigarette smoking, which also produces chronic pulmonary inflammation, may be associated with iron accumulation in alveolar macrophages (AM). We have examined the total iron content in human AM and found it to be 43.0 +/- 7.7 (mean +/- SEM) and 12.8 +/- 1.3 nmol/1 X 10(6) cells (P less than 0.01) from smokers and nonsmokers, respectively. Because the higher iron content in smokers' macrophages may reflect increased internalization, the binding and uptake of iron-saturated transferrin was examined in cells from smokers and nonsmokers. However, no significant differences were found between the two groups. The smoking-related alteration in iron content may instead reflect differences in the fate of internalized iron. Iron internalized by AM as iron 59 initially bound to transferrin was distributed to a cytoplasmic, largely ferritin-associated, pool more slowly in smokers than in nonsmokers, during a 24-hour incubation in vitro. Significantly less newly internalized iron was returned to the culture medium by AM from smokers, which by 24 hours had released 11.0% +/- 3.7% of the initially internalized 59Fe compared with 36.0% +/- 2.3% for nonsmokers (P less than 0.01). The increased accumulation of iron by AM in the alveolar space of smokers may modulate hydroxyl radical production in the microenvironment of these cells.     

Antioxidant macromolecules in the epithelial lining fluid of the normal human lower respiratory tract.

We hypothesized that the alveolar structures may contain extracellular macromolecules with antioxidant properties to defend against oxidants. To evaluate this 51Cr-labeled human lung fibroblasts (HFL-1) and cat lung epithelial cells (AKD) were exposed to a H2O2-generating system and alveolar epithelial lining fluid (ELF) from healthy nonsmokers was tested for its ability to protect the lung cells from H2O2-mediated injury. The ELF provided marked antioxidant protection, with most from a H2O-soluble fraction in the 100-300-kD range. Plasma proteins with anti-H2O2 properties were in insufficient concentrations to provide the antioxidant protection observed. However, catalase, a normal intracellular antioxidant, was present in sufficient concentration to account for most of the observed anti-H2O2 properties of ELF. Depletion of ELF with an anticatalase antibody abolished the anti-H2O2 macromolecular defenses of ELF. Since catalase is not normally released by cells, a likely explanation for its presence in high concentrations in normal ELF is that it is released by lung inflammatory and parenchymal cells onto the epithelial surface of the lower respiratory tract during their normal turnover and collects there due to the slow turnover of ELF. It is likely that catalase in the ELF of normal individuals plays a role in protecting lung parenchymal cells against oxidants present in the extracellular milieu.     

Lower respiratory tract iron burden is increased in association with cigarette smoking

Iron, by catalyzing the generation of the hydroxyl radical via the Haber-Weiss reaction, may participate in oxidant tissue injury. To determine whether iron might contribute to cigarette smoke-induced lung injury, we estimated the iron content of the lower respiratory tract by measuring intracellular iron content of pulmonary macrophages and extracellular iron content of bronchoalveolar lavage fluid from cigarette smokers and nonsmokers. Bronchoalveolar lavage was performed by using methods that allow for recovery of samples enriched for bronchial and alveolar contents. The intracellular iron content of the alveolar macrophages was determined by staining cytocentrifuged, air-dried pulmonary macrophages with a modified Prussian blue stain and assigning a score of 0 to 3 (0 = no stain, 3 = dense staining throughout the cytoplasm) to 100 macrophages. The extracellular iron level of bronchoalveolar lavage fluid was determined by using modifications of the Ferrozine method of Carter. Macrophage intracellular iron content was measured in a group of cigarette smokers with chronic bronchitis (n = 17), in smokers without chronic bronchitis (n = 15), and in normal volunteers (n = 15). Extracellular iron concentration was determined in a subset of the subjects with chronic bronchitis (n = 12) and in a separate group of normal volunteers (n = 5). The intracellular iron score was elevated in the bronchial sample lavage fluid in both the smokers with chronic bronchitis (45.3 +/- 13.9) and the asymptomatic smokers (26.6 +/- 8.0) compared with the normal individuals (8.1 +/- 1.7, p less than 0.03, both comparisons), but did not differ between the two groups of cigarette-smoking subjects (p = 0.68).(ABSTRACT TRUNCATED AT 250 WORDS)     

Antibiotic uptake by alveolar macrophages of smokers.

Cigarette smoking, particularly when associated with chronic pulmonary disease, increases the risk of respiratory tract infection. Thus, we elevated the uptake of antibiotics by alveolar macrophages (AM) obtained by bronchoalveolar lavage from persons who smoke and have associated pulmonary abnormalities, circumstances which adversely affect certain macrophage functions. The entry of radiolabeled drugs into AM was determined by a velocity-gradient centrifugation technique, and uptake was expressed as the ratio of cellular to extracellular antibiotic concentration (C/E). Cefamandole and penicillin G were taken up poorly by the AM obtained from smokers (C/E less than or equal to 1). Cellular levels of isoniazid, gentamicin, and tetracycline were similar to their extracellular concentrations. The lipid-soluble drugs lincomycin, chloramphenicol, and rifampin were concentrated severalfold by the AM from smokers (C/E = 3 to 11). Ethambutol also entered macrophages readily (C/E = 11). Erythromycin and clindamycin were massively concentrated by the AM from smokers (C/E = 23 to 56). The AM of smokers accumulated a lipid-soluble antibiotic (rifampin) and actively transported agents (erythromycin propionate, clindamycin) more avidly than did the AM of nonsmokers. Augmented uptake of these antibiotics by the AM of smokers may be related to structural and functional alterations induced by smoking.     

Effect of smoking on plasma neutrophil elastase levels

Plasma elastase is considered to indicate neutrophil elastase that has been released in vivo and has complexed with plasma inhibitors. Because smoking may play a pathogenetic role in emphysema by inducing elastase release in the lung, which may be reflected in the plasma elastase level, we evaluated the effect of smoking on plasma elastase in healthy men by using an enzyme-linked immunosorbent assay. No significant difference was found in plasma elastase levels between 30 smokers and 29 nonsmokers (103 +/- 23 [SD] ng/ml vs. 97 +/- 23 ng/ml). We found no significant change in plasma elastase level in eight heavy smokers when we compared morning with afternoon plasma samples taken about 7 hours later, while the subjects continued to smoke ad libitum in the interval. However, we found a significant rise in plasma elastase level in 12 healthy smokers who were tested after 8 hours of abstinence from smoking and then immediately and 1/2, 1, and 2 hours after intense smoking (eight cigarettes smoked over a period of 2 hours). Neutrophil count increased from a baseline of 3.8 +/- 0.7 X 10(3)/mm3 to 8.0 +/- 2.5 X 10(3)/mm3 at 1 hour, and 8.8 +/- 3.1 X 10(3)/mm3 at 2 hours. Plasma elastase level increased significantly (P less than 0.02) from a baseline of 111 +/- 30 ng/ml to 141 +/- 24 ng/ml at 1 hour after completion of smoking, but was not significantly different from baseline 2 hours after smoking (130 +/- 34 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Intrapulmonary pharmacokinetics of clarithromycin and of erythromycin.

The intrapulmonary pharmacokinetics of orally administered clarithromycin (500 mg every 12 h for five doses) or erythromycin (250 mg every 6 h for nine doses) were studied in 32 healthy adult volunteers. Four of the subjects, two in the clarithromycin group and two in the erythromycin group, were smokers. Bronchoscopy, bronchoalveolar lavage, and venipuncture were performed at 4, 8, 12, 24, and 48 h after administration of the last dose of clarithromycin and at 4, 8, and 12 h after administration of the last dose of erythromycin. Clarithromycin was measured by high-performance liquid chromatography, and erythromycin was measured by a microbiological assay. No systemic sedation was used. There were no major adverse events. The concentrations of antibiotics in epithelial lining fluid (ELF) were calculated by the urea dilution method. The volumes (mean +/- standard deviation) of ELF were 1.9 +/- 2.0 ml and 1.5 +/- 0.7 ml in the clarithromycin and erythromycin groups, respectively (P > 0.05). There was no effect of smoking on the amount of bronchoalveolar lavage fluid recovered, the volume of ELF, or the number of erythrocytes present in the lavage fluid (P > 0.05 for all comparisons). The total number of alveolar cells, however, was almost threefold greater in the smokers versus that in the nonsmokers (P < 0.05). Clarithromycin was concentrated in ELF (range, 72.1 +/- 73.0 micrograms/ml at 8 h to 11.9 +/- 3.6 micrograms/ml at 24 h) and alveolar cells (range, 505.8 +/- 293.1 micrograms/ml at 4 h to 17.0 +/- 34.0 micrograms/ml at 48 h). 14-(R)-Hydroxyclarithromycin was also present in these compartments, but at lower concentrations than the parent compound. The concentrations of erythromycin in ELF and alveolar cells were low at 4, 8, and 12 h following the last dose of drug (range, 0 to 0.8 +/- microgram/ml in ELF and 0 to 0.8 +/- 1.3 microgram/ml in alveolar cells). The clinical significance of any antibiotic concentrations in these compartments in unclear. The data suggest, and we conclude, that clarithromycin may be a useful drug in the treatment of pulmonary infections, particularly those caused by intracellular organisms.     

Aerosolized beta(2)-adrenergic agonists achieve therapeutic levels in the pulmonary edema fluid of ventilated patients with acute respiratory failure

OBJECTIVE: Experimental studies demonstrate that beta-adrenergic agonists markedly stimulate alveolar fluid clearance if concentrations of 10(-6) M are achieved in alveolar fluid. However, no studies have determined whether aerosolized beta-adrenergic agonists are delivered to the distal air spaces of the lung in therapeutic concentrations in patients with pulmonary edema. DESIGN AND SETTING: This retrospective study measured albuterol levels in the pulmonary edema fluid and plasma from mechanically ventilated patients with pulmonary edema from a hydrostatic mechanism ( n=10) or from acute lung injury ( n=12). MEASUREMENTS AND RESULTS: After a total aerosolized albuterol dose of 4.2+/-3.2 mg in the prior 6 h the median pulmonary edema fluid albuterol level was 1,250 ng/ml (10(-6) M) in patients with hydrostatic pulmonary edema; after 3.5+/-2.6 mg the figure was 1,240 ng/ml (10(-6) M) in patients with pulmonary edema from acute lung injury. Plasma albuterol levels were much lower, with a median of 5.2 ng/ml (0.01 x 10(-6) M) in patients with hydrostatic pulmonary edema and 3.1 ng/ml (0.01 x 10(-6) M) in patients with pulmonary edema from acute lung injury. CONCLUSIONS: These results provide the first evidence that levels of beta-adrenergic agonists that are physiologically efficacious in experimental models can be achieved with conventional delivery systems in ventilated, critically ill patients with acute respiratory failure from pulmonary edema.     

Increased nitric oxide elimination from the airways after smoking cessation

Smokers have been found to have low exhaled nitric oxide (NO) levels. The aim of the present study was to investigate where in the respiratory system the decrease in NO occurs, and whether this decrease was affected by smoking cessation. Measurements of exhaled NO were carried out in smokers (n=20) and non-smoking control subjects (n=30). In nine of the smokers, exhaled NO was analysed 1, 2 and 4 weeks after smoking cessation. The level of exhaled NO at a flow rate of 0.1 litre/s was significantly lower in smokers (4+/-2 p.p.b.) than in non-smokers (7+/-5 p.p.b.; P=0.007). A calculation of the contributions from different areas of the lung showed that the NO flux from the airways was significantly lower (14+/-10 compared with 36+/-26 nl/min; P=0.0001) and the alveolar fraction was significantly higher (2.1+/-0.8 compared with 1.5+/-0.9 p.p.b.; P=0.006) in smokers than in non-smokers. Nine smoking subjects refrained from smoking for 4 weeks, and this resulted in increased NO flux from the airways of 28+/-17 nl/min, which was no longer significantly different from controls. In conclusion, endogenous production of NO in the airways is decreased in smokers, but can be restored to normal values by 4 weeks after cessation of smoking. Smokers have an increased alveolar fraction of NO, and this might be a diagnostic sign of lung damage. Thus NO monitoring can be used to indicate improvements when a smoker decides to stop smoking.     

Human alveolar macrophages: comparison of phagocytic ability, glucose utilization, and ultrastructure in smokers and nonsmokers

Phagocytic ability, glucose utilization, and ultrastructural morphology were studied in human alveolar macrophages in smokers and nonsmokers. The macrophages were obtained by bronchopulmonary lavage and the studies were carried out in vitro in the absence of smoke. Phagocytic ability was measured as the decrease in the number of viable Staphylococcus albus organisms incubated with the macrophages. Measurements of (14)CO(2) formation from glucose-U-(14)C were made in a resting state. 90-95% of the cells obtained by lavage were large mononuclear macrophages of which approximately 90% remained viable at the end of the experiment. Smokers yielded many more macrophages per lavage (mean 46.4 x 10(6) +/-7.4) compared to the nonsmokers (mean 10.2 x 10(6) +/-2.3). The decline in viable organisms was the same in each group, indicating phagocytic competence of alveolar macrophages removed from smokers. However, the mean glucose utilization for the smokers was 4.3 +/-0.2 mmumoles/10(6) cells and 1.4 +/-0.7 mmumoles/10(6) cells for the nonsmokers. This very significant difference (P < 0.0001) suggests that smokers' macrophages have a higher resting energy requirement than those of nonsmokers. Comparison of the ultrastructural morphology of the alveolar macrophages from each group reveals that the cells from smokers differ from those of nonsmokers in that they are slightly larger, and contain more golgi vesicles, endoplasmic reticulum, and residual bodies. The residual bodies in smokers' cells contain distinctive fiber-like inclusions.     

Induction of aryl hydrocarbon hydroxylase in human pulmonary alveolar macrophages by cigarette smoking

Pulmonary alveolar macrophages were obtained from healthy volunteers by saline pulmonary lavage, and aryl hydrocarbon hydroxylase was measured in the cells. Enzyme activity was low in cells from five nonsmokers with a mean of 0.008±0.004 U/10⁶ cells. Cells obtained from nine cigarette smokers contained higher enzyme levels, with a mean of 0.095±0.024 U/10⁶ cells. A former cigarette smoker was lavaged on five occasions. Enzyme activity during two lavages 4 mo apart were 0.010 and 0.009 U/10⁶ cells, respectively. 1 wk after smoking was resumed, the enzyme activity rose slightly to 0.013, and reached 0.041 U/10⁶ cells by 1 mo. Upon cessation of smoking, the enzyme activity returned to control levels by the next lavage, 2 mo later. These data indicate that aryl hydrocarbon hydroxylase may be induced in pulmonary alveolar macrophages of subjects chronically exposed to cigarette smoke.