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PubMed1993

Pharmacokinetics of recombinant secretory leukoprotease inhibitor aerosolized to normals and individuals with cystic fibrosis.

Recombinant secretory leukoprotease inhibitor (rSLPI), a recombinant form of a natural airway inhibitor of neutrophil elastase (NE), is a potential therapeutic agent for cystic fibrosis (CF), a condition characterized by airway derangement mediated in part by the large burden of NE on the CF respiratory epithelial surface. After in vitro studies that demonstrated that aerosolized rSLPI retains its form and function, rSLPI was administered via aerosol to normal individuals and individuals with CF to determine the pharmacokinetics of in vivo rSLPI augmentation of the anti-NE defenses of the respiratory epithelial surface. After rSLPI aerosolization to normal individuals (100 mg single dose or 100 mg twice daily for 1 wk) there was a marked increase in SLPI levels and anti-NE capacity in airway epithelial lining fluid (ELF) at 1 h, diminishing gradually over 4 to 12 h. Interestingly, the ELF SLPI levels and anti-NE capacity achieved 12 h after 1 wk of rSLPI aerosols were no different than those 12 h after a single dose of rSLPI, suggesting that rSLPI does not accumulate on the respiratory epithelial surface after aerosolization. The ability of rSLPI to suppress NE in vivo was evaluated by aerosolization of rSLPI to individuals with CF, first as an escalating dose to assess safety, and then at doses of 100 mg twice daily for 1 wk or 50 mg twice daily for 2 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed1995

Normal bronchial epithelial cells constitutively produce the anti-inflammatory cytokine interleukin-10, which is downregulated in cystic fibrosis.

Interleukin-10 (IL-10) is a potent regulatory cytokine that decreases inflammatory responses and T-cell stimulation. We have found that respiratory epithelial lining fluid (ELF) from patients with cystic fibrosis (CF) contains significantly less soluble IL-10 than ELF of healthy control subjects. Although macrophages from the chronically infected lungs of CF patients appear to be one source of IL-10, little or no intracellular IL-10 was found in bronchoalveolar lavage macrophages from healthy control subjects, suggesting that there must be another source of this cytokine in healthy lungs. We found that bronchial epithelial cells from healthy control subjects constitutively produce IL-10, which appears to be downregulated in CF patients. It is thus likely that the bronchial epithelium plays an important role in regulating the local immune response, producing IL-10 to decrease inflammation in the healthy lung. Conversely, downregulation of epithelial IL-10 production in CF airways may contribute to enhancing local inflammation and tissue damage.

Adult↗

PubMed1989

Recombinant DNA-produced alpha 1-antitrypsin administered by aerosol augments lower respiratory tract antineutrophil elastase defenses in individuals with alpha 1-antitrypsin deficiency.

Alpha 1-Antitrypsin (alpha 1AT) deficiency is characterized by insufficient amounts of alpha 1AT to protect the lower respiratory tract from neutrophil elastase, resulting in emphysema. Yeast-produced recombinant alpha 1AT (rAAT) has normal antielastase function but is associated with high renal clearance, thus obviating chronic intravenous administration. As an alternative, we evaluated aerosol administration of rAAT to alpha 1AT-deficient individuals. After aerosol administration of single doses of 10-200 mg of rAAT, epithelial lining fluid (ELF) alpha 1AT antineutrophil elastase defenses were augmented in proportion to the dose of rAAT administered. ELF alpha 1AT levels and antineutrophil elastase capacity 4 h after 200 mg rAAT aerosol were increased 40-fold over preaerosol levels, and were fivefold increased over baseline at 24 h after aerosol administration. rAAT was detectable in serum after aerosol, indicating that the lower respiratory tract epithelium may be permeable to rAAT, and that aerosolized rAAT is capable of gaining access to lung interstitium. No adverse clinical effects were noted. These observations demonstrate that aerosol administration of rAAT is safe and results in significant augmentation of lung antineutrophil elastase defenses, suggesting this method is a feasible approach to therapy. Because this approach is clinically unproven, further studies will be necessary to establish the long-term clinical efficacy of aerosol therapy in alpha 1AT deficiency.

Adult↗

PubMed1998

Evidence of potential regulation by interleukin-4 of the soluble intercellular adhesion molecule 1 level in patients with seasonal allergic rhinitis under provocation by a small amount of natural allergen.

Interleukin-4 (IL-4) and intercellular adhesion molecule 1 (ICAM-1) are assumed to be involved in the pathogenesis of allergic disease. In this study, we examined the potential link between IL-4 and soluble ICAM-1 (sICAM-1) levels in patients with allergic rhinitis. The levels of sICAM-1 and IL-4 in sera and in nasal epithelial lining fluids (ELF) from 12 patients with Japanese cedar pollinosis were measured preseason through postseason, and the results were compared with those from 7 healthy subjects. In sera from the allergic subjects, the levels of sICAM- 1 were upregulated during the early part of the season and downregulated during the middle of the season, with upregulation of the IL-4 levels. Moreover, a negative correlation was found between the serum sICAM-1 levels and serum IL-4 levels during the middle (r = -.80) and late (r = -.73) parts of the season. In ELF from allergic subjects, the levels of sICAM-1 were significantly upregulated during the early and middle parts of the season, and began to be downregulated during the late part of the season, with upregulation of the levels of IL-4. In conclusion, IL-4 possibly acts as a potential suppressor of sICAM-1 in the pathogenesis of seasonal allergic rhinitis, at least under provocation by a small amount of natural allergen.

Adult↗

PubMed2005

Penetration of ertapenem into different pulmonary compartments of patients undergoing lung surgery.

Ertapenem is approved for the treatment of community-acquired pneumonia (CAP), but its in vivo penetration into lung tissue (LT), epithelial lining fluid (ELF), and alveolar cells (AC) is unknown. Fifteen patients undergoing thoracotomy were treated with 1 g intravenously for perioperative prophylaxis. Bronchoalveolar lavage was performed 1, 3, and 5 hours after ertapenem infusion. Normal LT was sampled at the time of lung extraction. Blood was collected before and at different time points up to 24 hours after infusion. Mean concentrations of ertapenem in plasma, ELF, and AC were at 1.0 hour, 63.1, 4.06, 0.004 mg/L; at 3.0 hours, 39.7, 2.59, 0.003 mg/L; and at 5.0 hours, 27.2, 2.83, 0.007 mg/L. Mean (range) concentration in LT was 7.60 (2.5-19.4) mg/kg tissue 1.5 to 4.5 hours after infusion. In plasma, ertapenem exhibited a Cmax of 94.7 +/- 23.3 mg/L and an AUC(0-last) of 501.1 +/- 266.3 mg x h/L. These results, combined with the reported (MIC)90 of most CAP bacteria, support the previously observed clinical efficacy of ertapenem in the treatment of CAP.

Adult↗

PubMed2004

Cellular effects of electromagnetic fields.

Studies at the cellular level are needed to reveal the cellular and molecular biological mechanisms underlying the biological effects and possible health implications of non-ionising radiation, such as extremely low frequency (ELF) magnetic fields (MFs) and radiofrequency (RF) fields. Our research group has studied the effects of 50 Hz ELF MFs (caused by power lines and electric devices) and 872 MHz or 900 MHz RFs (emitted by mobile phones and their base stations) on cellular ornithine decarboxylase activity, cell cycle kinetics, cell proliferation, and necrotic or apoptotic cell death. For RFs, pulse-modulated (217 Hz modulation frequency corresponding a global system for mobile communication-type signal) or continuous wave (unmodulated) signals were used. To expose the cell cultures to MFs or RFs, specially developed exposure systems were used, where levels of electromagnetic field exposure and the conditions of cell culture could be precisely controlled. A coexposure approach was used in many studies, i.e. the cell cultures were exposed to other stressors in addition to MFs or RFs. Ultraviolet radiation, serum deprivation, or fresh medium addition, were used as co-exposures. The results presented in this short review show that the effects of mere MFs or RF on cell culture models are quite minor, but that various co-exposure approaches warrant additional study.

Animal Testing Alternatives↗

PubMed2000

New insight into the clinical pharmacokinetics of cefaclor: tissue penetration.

The serum pharmacokinetic data presented are generally in agreement with those obtained by other authors with both the cefaclor IR (immediate release) and AF (advanced formulation) or MR (modified release) formulations. With the new sustained-release formulation, the time of peak (Tmax) and mean residence time (MRT) values are significantly longer than those observed with the standard cefaclor IR. For the first time the penetration of the MR formulation of cefaclor was determined both in suction blister fluid (SBF) and alveolar epithelial lining fluid (ELF). Cefaclor demonstrated a high tissue distribution, with a high penetration index (PI) into blister fluid, which is at least representative of a relatively large volume of fluid-filled spaces and in part of highly vascularized tissues. SBF and ELF concentrations were higher than blood levels starting at the 4th-6th hour after dose, with longer elimination half-lives from the extravascular compartment than from serum. Cefaclor has a favorable pharmacokinetic profile, especially the new sustained-release formulation, which maintains effective concentrations for a longer time than the IR preparation. The MR formulation improves the kinetic properties of the cefaclor molecule with a prolonged MRT which allows a daily dosage of 750 mg every 12 h.

Aged↗

PubMed2001

Pulmonary disposition of lomefloxacin in patients with acute exacerbation of chronic obstructive pulmonary disease. A multiple-dose study.

In this study we have measured the concentrations of lomefloxacin at steady state in serum and in the intrapulmonary region at specified intervals for 24 h following administration of the last dose of drug in patients suffering from acute exacerbation of chronic obstructive pulmonary disease (COPD). Twenty subjects were enrolled. They received lomefloxacin 400 mg orally once-daily for 5 consecutive days. All patients were divided into five groups, with 4 subjects in each group, according to sampling times (2, 4, 8, 12, and 24 h after the last dose). At bronchoscopy, bronchial biopsies and bronchoalveolar lavage (BAL) were performed. At 12 h after the last dose, serum concentration of lomefloxacin was >1.0 microg/mL and at 24 h it was still detectable, but, at all times, the concentrations in bronchial secretion, bronchial mucosa, and epithelial lining fluid (ELF) were greater than the concentrations in serum [bronchial secretions (pg/mL) = 2.5+/-1.2; 2.2+/-1.0: 2.0+/-1.1; 1.8+/-1.1; 0.6+/-0.3. bronchial mucosa (microg/g) = 5.9+/-2.1; 6.2+/-1.8; 2.6+/-2.2; 1.9+/-1.5; 1.0+/-0.9. ELF (microg/mL) = 6.9+/-2.8; 5.9+/-2.6; 3.1+/-1.9; 2.2+/-1.0; 0.8+/-1.3. serum (microg/mL) = 3.2+/-1.4; 2.8+/-0.9: 2.1+/-1.5; 1.2+/-1.1; 0.4+/-0.81. We must stress that we observed a large inter-individual variability in concentrations. Our data show that lomefloxacin once-daily induces high and sustained concentrations in the various potential sites of pulmonary infection and clearly indicate that the pharmacokinetic behavior of this fluoroquinolone permits once-daily administration in patients with acute exacerbations of COPD.

Administration, Oral↗

PubMed1995

Increased oxidation of extracellular glutathione by bronchoalveolar inflammatory cells in diffuse fibrosing alveolitis.

An unbalanced oxidative stress is thought to be an important element in the pathogenesis of diffuse fibrosing alveolitis (DFA). The purpose of our study was to investigate the role of reactive oxygen metabolites (ROMs) released from cultured bronchoalveolar inflammatory cells (BA-cells) on glutathione oxidation. We studied bronchoalveolar lavage samples from 10 healthy controls and from 20 patients with diffuse fibrosing alveolitis (all were nonsmokers). BA-cells obtained by bronchoalveolar lavage (BAL) were incubated with 50 microM of reduced glutathione (GSH). Oxidation of GSH to glutathione disulphide (GSSG) by BA-cell derived oxidants was detected as a decline of GSH in the supernatants. Total glutathione (GSHtot = GSH + 2 GSSG) and GSSG in the epithelial lining fluid (ELF), and methionine sulphoxide (Met(O)) content of BAL proteins were determined. In diffuse fibrosing alveolitis the oxidative activity of BA-cells was enhanced, GSHtot and GSH were decreased, whereas the GSSG:GSH ratio was increased. The oxidative activity of BA-cells correlated positively with the GSSG:GSH ratio, but not with the methionine sulphoxide content. The methionine sulphoxide content was elevated in diffuse fibrosing alveolitis and inversely correlated with GSHtot. The methionine sulphoxide content also correlated positively with the percentage of BAL neutrophils. We conclude that BA-cell-derived reactive oxygen species are capable of oxidizing extracellular GSH in vitro. The positive correlation between the BA-cell oxidative activity in vitro and GSSG:GSH ratio in ELF suggests that a similar oxidative effect on extracellular GSH may also occur in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1999

Clinical and immunoregulatory effects of roxithromycin therapy for chronic respiratory tract infection.

The clinical and immunoregulatory effects of long-term macrolide antibiotic therapy for patients with chronic lower respiratory tract infections (CLRTI) were investigated. Clinical parameters and neutrophil chemotactic mediators in the epithelial lining fluid (ELF) of CLRTI patients (n = 10) were examined before and after 3 months oral administration of roxithromycin (RXM). The in vitro effects of RXM were also examined on the release of these mediators from alveolar macrophages (AM) and neutrophils. Arterial oxygen tension (p<0.05), vital capacity (VC) (p<0.001), %VC (p<0.05) and forced expiratory volume in one second (p<0.01) were improved after RXM treatment, but airway bacteria were not eradicated. Among the mediators, the levels of interleukin (IL)-8, neutrophil elastase (NE) and leukotriene B4 (LTB4) were higher in ELF than in plasma of CLRTI patients and they decreased after RXM treatment (n = 7, p<0.05 for each). RXM concentrations were significantly increased in the bronchoalveolar lavage cells of the treated patients. In in vitro experiments, RXM showed inhibitory effects on IL-8 release from AM and neutrophils. In conclusion, interleukin-8, neutrophil elastase and leukotriene B4 contribute to the neutrophilic inflammation in the airways of chronic lower respiratory tract infection patients and the clinical effects of roxithromycin may, in part, be attributable to the suppression of excess release of the chemotactic mediators from inflammatory cells.

Anti-Bacterial Agents↗

PubMed1998

[Flow cytometric analysis of the effects of 50 Hz magnetic fields on mouse spermatogenesis].

The cellular effects of an extremely-low-frequency (ELF) magnetic field on mouse spermatogenesis were assessed by DNA flow cytometry and serum testosterone. Seven week old male ICR mice were exposed to a 50 Hz magnetic field the strength of which was 1.0 m Tesla. Seven mice per treatment group were exposed for 13, 26, 39 or 52 days. For each experimental point, an equal number of mice per sham-treated group were used as a control and were exposed only to the background field below 1 mu Tesla in the same room as the treatment group. In the control mice, the testis cellular DNA content distribution by flow cytometory was characterized by four quantifiable populations; round spermatids (1C), spermatogonia and other diploid cells (2C), spermatogonial cells synthesizing DNA (S-phase) and primary spermatocytes (4C). In animals exposed for 26 days the number of cells in the 4C and the 4C:2C ratio was significantly lower, and the 1C:4C ratio (meiotic transformation) was significantly higher than the corresponding control groups. In animals exposed for 52 days the cell population in 1C and the 1C:2C ratio (total germ-cell transformation) was significantly higher, and the cell population in 2C was significantly lower than the corresponding control groups. The concentration of serum testosterone in animals exposed for 13 days was significantly higher than in the corresponding control group. These changes suggest that long-term exposure to an ELF magnetic field had a possible effect on the proliferation and differentiation of spermatogonia.

Animals↗

PubMed2004

Alveolar granulocyte colony-stimulating factor and alpha-chemokines in relation to serum levels, pulmonary neutrophilia, and severity of lung injury in ARDS.

OBJECTIVES: To determine granulocyte colony-stimulating factor (G-CSF), epithelial neutrophil-activating peptide (ENA)-78, and interleukin (IL)-8 in BAL fluid (BALF), epithelial lining fluid (ELF), and serum for establishing the concentration gradient of G-CSF, ENA-78, and IL-8 between the blood and the alveolar space in ARDS and acute lung injury (ALI); and to evaluate the relationship of G-CSF, IL-8, and ENA-78 to pulmonary neutrophilia and severity of lung injury. DESIGN: Prospective study. SETTING: An adult trauma/surgical ICU. PATIENTS: Nineteen patients with ARDS and 10 patients with ALI. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: BAL and blood sampling simultaneously within 12 h and 24 h after onset of ARDS/ALI; G-CSF was detected in BALF in 18 of 19 patients with ARDS, in 7 of 10 patients with ALI, and in all serum samples. G-CSF in BALF and serum was significantly higher in ARDS than in ALI. ENA-78 was detected in BALF in 14 of 19 patients with ARDS, in 8 of 10 patients with ALI, and in serum of all patients. Levels in BALF and serum were not different between ARDS and ALI. IL-8 was detected in all patients; concentrations in BALF in ARDS were significantly higher than in ALI. Concentrations of G-CSF, ENA-78, and IL-8 in ELF were significantly higher than in serum. G-CSF in BALF and serum and IL-8 in BALF correlated positively with pulmonary neutrophilia. G-CSF in serum and IL-8 in BALF correlated negatively with PaO(2)/fraction of inspired oxygen (FIO(2)) ratio. However, ENA-78 did not show a correlation with neutrophil count or with PaO(2)/FIO(2) ratio. CONCLUSIONS: G-CSF may be pathophysiologically important for accumulation and activation of neutrophils in ARDS. Local G-CSF production is the likely driving force for neutrophils rather than elevation of circulating levels. In comparison to ENA-78, IL-8 seems to be the predominant neutrophil chemoattractant in the early phase of ARDS.

Adult↗

PubMed1991

[Electromagnetic fields: their biological effects and regulation].

Concern over the effects of humans of ELF-(extremely low frequency; less than 300 Hz) electromagnetic fields has rapidly increased in recent years. The effects seem to be related to gene level aberrations such as carcinogenesis and developmental malformations, but it is difficult to obtain experimental evidences on field effects. Several safety guidelines or permissible doses have been proposed for electromagnetic wave, but they mainly cover the range of microwave frequencies. Three of the guidelines made in 1989-1990 included ELF-electromagnetic fields and two newly approved guidelines on power-frequency electromagnetic fields appeared in 1990. However, they adopted considerably different values based on different theoretical standpoints. Generally, the concept of electromagnetic fields appears to be confused with that of magnetic field and thus the ideas for protective measures conflict between the two. The author first presented the concepts of electromagnetic and magnetic fields, then briefly discussed their biological effects together with the underlying mechanism, and lastly described these drafts on safety standards or permissible doses. Since subtle and difficult problems remain to be resolved, further investigation will be required in order to put these guidelines into practice.

Electromagnetic Fields↗

PubMed2005

The sensitivity of children to electromagnetic fields.

In today's world, technologic developments bring social and economic benefits to large sections of society; however, the health consequences of these developments can be difficult to predict and manage. With rapid advances in electromagnetic field (EMF) technologies and communications, children are increasingly exposed to EMFs at earlier and earlier ages. Consistent epidemiologic evidence of an association between childhood leukemia and exposure to extremely low frequency (ELF) magnetic fields has led to their classification by the International Agency for Research on Cancer as a "possible human carcinogen." Concerns about the potential vulnerability of children to radio frequency (RF) fields have been raised because of the potentially greater susceptibility of their developing nervous systems; in addition, their brain tissue is more conductive, RF penetration is greater relative to head size, and they will have a longer lifetime of exposure than adults. To evaluate information relevant to children's sensitivity to both ELF and RF EMFs and to identify research needs, the World Health Organization held an expert workshop in Istanbul, Turkey, in June 2004. This article is based on discussions from the workshop and provides background information on the development of the embryo, fetus, and child, with particular attention to the developing brain; an outline of childhood susceptibility to environmental toxicants and childhood diseases implicated in EMF studies; and a review of childhood exposure to EMFs. It also includes an assessment of the potential susceptibility of children to EMFs and concludes with a recommendation for additional research and the development of precautionary policies in the face of scientific uncertainty.

Brain Neoplasms↗

PubMed2005

Stereological analysis of thyroid mast cells in rats after exposure to extremely low frequency electromagnetic field and the following "off" field period.

Influence of extremely low frequency electromagnetic field (ELF-EMF) on thyroid gland mast cells was investigated on male Mill Hill rats. Animals were exposed to EMF (50 Hz, 50 microT to 500 microT, 10 V/m) from 24 hours after birth, 7 hours/day, 5 days/week for three months when a part of animals (group I) was sacrificed, while the rest of them were subjected to recovery evaluation and sacrificed after one (group II), two (group II) and three (group IV) weeks following the exposure. Stereological analysis on toluidine blue-stained paraffin sections showed increased volume density of degranulated mast cells in all groups and, except in group III, and numerical density as well, implicating the sensitivity of thyroidal mast cells to power frequency EMFs. Since in our previous investigations, morphofunctional alterations of thyroid gland in rats exposed to ELF-EMF were found the contribution of released mast cell mediators to these changes could be presumed.

Animals↗

PubMed2000

Induction of interleukin-8 release by lung epithelium with cystic fibrosis epithelial lining fluid is marginally affected by inhibitors of interleukin-1beta.

Interleukin-1beta (IL-1beta) and neutrophil elastase (NE) are present in the epithelial lining fluid (ELF) of patients with cystic fibrosis (CF). Both factors activate surrounding cells including lung epithelial cells, causing release of IL-8, a potent chemoattractant for neutrophils. Previous studies showed up-regulation of IL-8 release by lung epithelial cells as a function of NE in CF; however, few studies addressed the relationship between IL-1beta and activation of lung epithelial cells in CF lungs. Confluent layers of A549 cells, a type II-like human lung epithelial cell line, were incubated overnight with IL-1beta (0-5 ng/ml) or NE (100 nM), and supernatants were analyzed for IL-8 by enzyme-linked immunosorbent assay (ELISA). Both IL-1beta and NE led to a significant increase in IL-8: 12.8 +/- 2.8 ng/ml and 0.8 +/- 0.3 ng/ml, respectively. Next, bronchoalveolar lavage (BAL) samples were obtained from one healthy adult volunteer and six patients with CF and measured for IL-8 and IL-1beta concentrations by ELISA. Both IL-8 (range 169.00 +/- 56.57 to 1742.04 +/- 338.98 pg/ml) and IL-1beta (range 0-24.26 +/- 0.52 pg/ml) were detected in CF specimens, whereas neither was detected in the volunteer's specimen. Normal and CF BALs then were incubated overnight at a 1:10 dilution with confluent A549 cells. Analysis by ELISA of cell-free supernatants revealed increased IL-8 production from cells stimulated with CF BALs only. Similar experiments were performed with BAL supernatants that had been incubated with soluble IL-1 type II receptor, soluble IL-1 receptor antagonist, or a peptide inhibitor of NE. Addition of IL-1 inhibitors had a marginal effect on the amount of IL-8 release after incubation with CF BAL samples, whereas inhibition of NE had no effect. Our results indicate that other factors present in ELF in CF account for IL-8 release from lung epithelial cells.

Adolescent↗

PubMed2000

Suppression of a differentiation response in MC-3T3-E1 osteoblast-like cells by sustained, low-level, 30 Hz magnetic-field exposure.

Extremely low-frequency (ELF) magnetic fields have been reported to be capable of influencing both tissue remodeling and cell phenotypic expression in culture. However, whether the cells or tissues respond directly to the magnetic flux or to the electric field induced by the time-changing magnetic flux remains a controversial topic. To address this question, we developed an osteoblast cell assay based on the activity of alkaline phosphatase, an enzyme whose activity is up-regulated during the differentiation of bone cells. MC-3T3-E1 cells plated at a confluent density were allowed to proceed through the differentiation process for 3 days, after which they were exposed to a 30 Hz, 1.8-mT r.m.s. magnetic field inducing a spatially varying electric field with a maximum intensity of 0.9 mV/m r.m.s. In situ assays of alkaline phosphatase activity at 4, 8, 16 and 64 h demonstrated a progressive inhibition of enzyme activity, the pattern of which maps to the intensity of the induced electric field (R(2) = 0.5, P<0.001). We interpret these results to indicate that cells are capable of responding to ELF induced electric fields at intensities below 1 mV/m, and that the principal effect on cells is an inhibition of differentiation.

Alkaline Phosphatase↗

PubMed2001

Plasma and bronchoalveolar fluid concentrations of nitric oxide and localization of nitric oxide synthesis in the lungs of horses with summer pasture-associated obstructive pulmonary disease.

OBJECTIVE: To determine concentrations of nitric oxide (NO) in plasma and bronchoalveolar lavage fluid (BALF) and localize nitric oxide synthesis in the lungs of horses with summer pasture-associated obstructive pulmonary disease (SPAOPD). ANIMALS: 7 adult horses with SPAOPD and 6 clinically normal adult horses. PROCEDURE: Severity of SPAOPD was determined by use of clinical scores, change in intrapleural pressure (APpl) during tidal breathing, cytologic analysis of BALF, and histologic evaluation of lung specimens obtained during necropsy. Nitric oxide concentrations in plasma, BALF and epithelial lining fluid (ELF) were determined by use of a chemiluminescent method. Inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT) were localized in formalin-fixed lung specimens by use of immunohistochemical staining, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) activity was localized in cryopreserved specimens by use of histochemical staining. RESULTS: Plasma concentration of NO in affected horses was slightly but not significantly greater than concentration in nonaffected horses. Nitric oxide concentrations in BALF or ELF did not differ between groups. Immunoreactivity of iNOS in bronchial epithelial cells of 3 of 5 lung lobes was greater in horses with SPAOPD, compared with nonaffected horses. However, staining for NT and NADPHd activity did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Expression of iNOS was greater in bronchial epithelial cells of horses with SPAOPD, compared with nonaffected horses, suggesting that NO may play a role in amplifying the inflammatory process in the airways of horses with this disease.

Animals↗