Angelo Fasoli

Cellular and biochemical characteristics of bronchoalveolar lavage fluid in symptomatic nonallergic asthma

We have undertaken cellular and biochemical examination of bronchoalveolar lavage fluid from nonallergic patients with asthma to determine the nature and degree of inflammatory process in symptomatic asthma. Six patients with asthma (mean methacholine provocative concentration causing a 20% fall in FEV1 was 0.26 mg/ml) and six control subjects underwent fiberoptic bronchoscopy with bronchoalveolar wash. The patients with asthma shed a higher number of epithelial cells into lavage fluid than normal control subjects (p less than 0.05). Their lavage fluid also contained increased numbers of neutrophils (p less than 0.025), eosinophils (p less than 0.025), and basophilic cells (p less than 0.025), and increased proportion of activated T cells (p less than 0.05). The basophilic cells were mast cells, as indicated by positive labeling with the monoclonal antibody MCG35. Biochemical analysis of lavage fluid demonstrated exudation of protein molecules in airways of patients with asthma with increased contents of albumin (p less than 0.05) and fibronectin (p less than 0.05). In the lavage fluid of patients with asthma, there were also increased amounts of interleukin-1-beta (IL-1-beta) (p less than 0.025), interleukin-6 (IL-6) (p less than 0.025), and granulocyte-macrophage, colony-stimulating factor (GM-CSF) (p less than 0.05), as compared with lavage fluid of normal control subjects. Immunocytochemical evaluation of lavage cells demonstrated that IL-1-beta, IL-6, and GM-CSF were mostly produced by nonciliated epithelial cells and/or monocytes. IL-1, IL-6, and GM-CSF can prime granulocytes to respond to other stimuli and can promote T cell activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Levels of endothelin in the bronchoalveolar lavage fluid of patients with symptomatic asthma and reversible airflow obstruction

We have previously demonstrated that human bronchial smooth muscle cells possess a single class of specific binding sites for the potent bronchoconstrictive peptide, endothelin 1, and that human bronchial epithelial cells constitutively release an endothelin-like material in culture, which binds to smooth muscle cell receptors with a kinetic analogous to that observed with the authentic peptide. To evaluate the potential role of endothelin in the pathogenesis of asthma, we examined in this study the release of endothelin in the airways of six patients with asthma, both at the time when they were symptomatic and had reversible airflow obstruction and during the remission phase of the disease induced by treatment. Five normal volunteers and five patients with chronic bronchitis and airflow obstruction unaffected by bronchodilators were tested as control subjects. The release of endothelin in airway mucosa was assessed by RIA with the bronchoalveolar lavage fluid recovered during bronchoscopy. Patients with asthma had increased amounts of immunoreactive endothelin in bronchoalveolar lavage fluid than normal control subjects or subjects with chronic bronchitis (p less than 0.05) in absence of any significant alteration in the levels of circulating peptide. Treatment of patients with asthma with oral corticosteroids and inhaled beta-agonists for 15 days resulted in improvement of airflow obstruction and in more than threefold reduction in the contents of endothelin in lavage fluid. Our findings indicate that the potent bronchoconstrictive substance, endothelin, may contribute to the pathogenesis of airflow obstruction in asthma.

Human bronchial epithelial cells modulate CD3 and mitogen-induced DNA synthesis in T cells but function poorly as antigen-presenting cells compared to pulmonary macrophages

This study was undertaken to investigate the ability of bronchial epithelial cells (ECs) to function as accessory cells. Pulmonary monocytes were our reference cells. ECs and pulmonary monocytes were isolated from the bronchial mucosa and pulmonary parenchyma of subjects undergoing lobectomy for standard clinical reasons. Circulating autologous T cells were rigorously depleted of accessory cells to the extent that they lost the capacity to respond to mitogenic lectins alone. ECs restored mitogen-induced DNA synthesis and DNA synthesis triggered by CD3 cross-linking in T cells, as did pulmonary macrophages, and this was unrelated to HLA-DR expression. The ability of promoting T cell proliferation after CD3 cross-linking was, in part, due to the secretory products of ECs, since their supernatants were also effective. Interferon-gamma-treated ECs were capable of presenting antigens to autologous T cells. This was an HLA-DR-restricted phenomenon, but EC efficiency in this system was less than 40% of efficiency demonstrated by pulmonary monocytes. However, ECs greatly upregulated antigen-specific responses supported by pulmonary monocytes.

Nedocromil Sodium Prevents the Release of 15-Hydroxyeicosatetraenoic Acid from Human Bronchial Epithelial Cells Exposed to Toluene Diisocyanate in vitro

The in vivo exposure to an asthmogenic stimulus, toluene diisocyanate (TDI), causes airway epithelial damage associated with inflammation and increased bronchial hyperresponsiveness. The latter mechanisms might partly be mediated by the release of eicosanoids from bronchial epithelial cells. We have previously demonstrated that the in vitro exposure of bronchial epithelial cells to TDI results in the release of immunoreactive 15-hydroxyeicosatetraenoic acid (15-HETE), a product of activation of the 15-lipoxygenase pathway with inflammatory properties. In the present study we show that TDI-induced release of 15-HETE from epithelial cells can be prevented by nedocromil sodium, an anti-asthmatic drug with anti-inflammatory properties. This mode of action of the compound may explain its clinical effectiveness in asthma.

The protective effect of frusemide on the generation of superoxide anions by human bronchial epithelial cells and pulmonary macrophages in vitro

Inhaled frusemide has been shown to inhibit bronchoconstriction induced by immunological and nonimmunological stimuli in asthmatic patients. The mechanisms by which this compound exerts its effect in asthmatic airways are unknown, but an inhibitory action on the activation of inflammatory cells or on the responsiveness of sensory epithelial nerves may be involved. In this study, we give evidence that frusemide prevents in part the activation of bronchial epithelial cells and pulmonary macrophages, as it reduces the rate of superoxide anion generation induced by IgE receptor cross-linking and by phorbol myristate acetate by 40-60%. The effect was not specific since we used stimuli which activate different signal transduction pathways for NADPH oxidase stimulation and frusemide was equally effective.

Effects of slow release bezafibrate on the lipid pattern and on blood glucose of type 2 diabetic patients with hyperlipidaemia

Ninety-eight type 2 diabetic patients with hyperlipidaemia in stable metabolic control with diet alone (41) or diet plus hypoglycaemic agents (57) were divided into two groups: group 1 was put on treatment with slow release bezafibrate 400 mg a day, while group 2 was considered as control. In group 1, after 1 month of bezafibrate, serum triglycerides fell by 47% and cholesterol by 13%. HDL cholesterol showed a non-significant trend toward an increase. Fasting blood glucose significantly decreased by 6%, fructosamine and glycated haemoglobin by 5%. During OGTT, the area under the curve of both serum C-peptide and blood glucose showed a trend toward a decrease after bezafibrate. However, the difference did not reach statistical significance. Thirty-six patients continued the treatment with the drug for 4 months and 23 for 8 months, without further changes of the lipid pattern and glycaemic control. In the control group no significant variation of the lipid levels occurred and diabetic control slightly worsened during the study. Bezafibrate has been proved to be effective in the treatment of hyperlipidaemia in type 2 diabetic patients. The drug seems moreover to improve glycaemic control. The mechanism by which bezafibrate produces this latter effect remains to be elucidated, though an increase of peripheral insulin sensitivity might be suggested.

Bezafibrate inhibits HMG-CoA reductase activity in incubated blood mononuclear cells from normal subjects and patients with heterozygous familial hypercholesterolaemia.

In incubated blood mononuclear cells from normal subjects bezafibrate inhibited the incorporation of 14C-acetate into squalene, methylsterols and cholesterol. Similarly, the drug produced a sharp decrease of the incorporation of labelled 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) into non-saponifiable lipids, while the incorporation of 14C-mevalonate was unaffected by the presence of bezafibrate in the incubation mixture. This strongly suggests that bezafibrate inhibits HMG-CoA reductase activity. In cultured cells from patients with heterozygous familial hypercholesterolaemia the presence of bezafibrate in the incubation medium resulted in an inhibition of the incorporation of labelled acetate into non-saponifiable lipids. Bezafibrate then inhibits cholesterol biosynthesis in cells from normal and hypercholesterolaemic patients and this effect is likely, to contribute to the hypocholesterolaemic activity of the drug.

Fenofibrate therapy of hypertriglyceridaemias. Differential effects on LDL cholesterol level in Type IV and in Type IIb primary hyperlipoproteinaemia

SummaryTwenty five hypertriglyceridaemic patients (16 Type IV and 9 Type IIb) were treated with fenofibrate 300 mg/d. In Type IV patients serum triglycerides and VLDL cholesterol decreased, while LDL and HDL cholesterol rose significantly. In Type IIb patients, triglycerides and total, VLDL, IDL and LDL cholesterol were significantly reduced by the treatment. The correction of hypertriglyceridaemia by fenofibrate seems, therefore, to induce different changes in lipoproteins in Type IIb and in Type IV hyperlipoproteinaemic patients. The practical implications of these results are discussed.

Low-fat diet versus low-carbohydrate diet in the treatment of type IV hyperlipoproteinaemia.

The response to dietary management was studied in 24 hypertriglyceridaemic out-patients. Fourteen patients were kept on a diet low in fat and cholesterol and high in polyunsaturated fatty acids; 10 of these patients subsequently followed a period of low-carbohydrate diet. At the end of the first period a significant decrease of serum triglyceride, cholesterol and beta-lipoproteins was observed; after the second feeding period no substantial change of serum lipoprotein pattern occurred. Ten patients were given a low-carbohydrate diet that produced a significant fall of the levels of triglycerides and pre-beta-lipoproteins. Six of these subjects continued the experiment with the low-fat diet; during this period a further trend toward reduction of serum triglyceride, cholesterol and beta-lipoproteins was observed which, however, was not statistically significant. We conclude that serum triglyceride levels can be lowered both by a low-carbohydrate diet and by a low-fat diet, but the latter has the advantage of also producing a significant fall of serum cholesterol and beta-lipoproteins.

Inactivation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in cultured human blood mononuclear cells by procetofenic acid.

Summary The effect of procetofenic acid on 3-hydroxy-3-methylglutaryl Coenzyme A reductase (HMG-CoA reductase) activity has been studied on cultured human blood mononuclear cells. The drug produced a sharp decrease in enzyme activity both when it was added to the incubation medium and when it was added to the HMG-CoA reductase assay mixture. These findings strongly suggest that procetofenic acid inhibits HMG-CoA reductase activity by inactivating enzyme protein or by interfering with enzyme-substrate interaction. Since HMG-CoA reductase is a rate-limiting enzyme in cholesterol biosynthesis, its inhibition may explain, at least in part, the hypocholesterolemic effect of the drug.