Prognostic bioindicators in severe COVID-19 patients.

BACKGROUND: Severe acute respiratory syndrome caused by novel coronavirus 2 (SARS-CoV-2) emerged in Wuhan (China) in December 2019. Here we evaluated a panel of biomarkers to phenotype patients and to define the role of immuno-inflammatory mediators as biomarkers of severity. MATERIALS AND METHODS: Serum samples were obtained from 24 COVID-19 patients on admission to hospital, before any treatment or infusion of intravenous steroids or invasive ventilation. KL-6 IL-6 and C-peptide were measured by chemiluminescent enzyme immunoassay. IL-6 assay was validated for accuracy and precision. The validity of variables used to distinguish severe from mild-to-moderate patients was assessed by areas under curves (AUC) of the receiver operating characteristic (ROC) and logistic regression was performed to combine parameters of the two groups. RESULTS: In the severe group, IL-6, CRP and KL-6 concentrations were significantly higher than in mild-to-moderate patients. KL-6, IL-6 and CRP concentrations were directly correlated with each other. ROC curve analysis of the logistic regression model including IL-6, KL-6 and CRP showed the best performance with an AUC of 0.95. CONCLUSIONS: Besides corroborating previous reports of over-expression of IL-6 in severe COVID-19 patients requiring mechanical ventilation, analytical determination of other mediators showed that IL-6 concentrations were correlated with those of KL-6 and CRP. The combination of these three prognostic bioindicators made it possible to distinguish severe COVID-19 patients with poor prognosis from mild-to-moderate patients.

Regulatory T Cells in Severe Persistent Asthma in the Era of Monoclonal Antibodies Target Therapies.

Asthma is an immunoinflammatory disease characterized by bronchial hyper-reactivity to different external stimuli. New monoclonal target treatments have been developed, but few studies have investigated the role of regulatory T cells in severe asthma and the modulatory effect of biological therapy on regulatory T cell functions. Their dysfunction may contribute to the development and exacerbation of asthma. Here we review the recent literature on the potential immunological role of regulatory T cells in the pathogenesis of severe asthma. The analysis of the role of regulatory T cells was performed in terms of functions and their possible interactions with mechanisms of action of the novel treatment for severe asthma. In an era of biological therapies for severe asthma, little data is available on the potential effects of what could be a new therapy: monoclonal antibody targeting of regulatory T cell numbers and functions.

Omalizumab treatment in Samter's triad: case series and review of the literature.

OBJECTIVE: Samter's triad is the combination of asthma, aspirin sensitization, and nasal polyposis. Few data are available on the use of omalizumab in this disease. The study aimed to describe the impact of omalizumab on clinical and functional parameters and the quality of life of a series of patients with Samter's triad. Moreover, we aimed to provide a review of the literature on this topic. PATIENTS AND METHODS: We retrospectively described four patients with Samter's triad undergoing omalizumab therapy. Clinical, functional, and immunological data of these patients were collected at baseline and follow-up. RESULTS: Reduction of asthma exacerbations and salbutamol rescue therapy were observed in all patients after anti-IgE treatment together with an improvement in the quality of life. A significant improvement in FEV1, FVC, and FEF25-75 was observed. No major side-effects were observed. A total of 14 studies regarding omalizumab in aspirin-exacerbated respiratory diseases were included in the review, comprising 78 patients. All studies reported a good efficacy in improving asthma control; restoration of aspirin tolerance was repeatedly reported. CONCLUSIONS: The results of our case series and review of the literature suggest that omalizumab effectively improves asthma control, lung function tests, and quality of life in patients with Samter's triad.

NK and NKT-like cells in granulomatous and fibrotic lung diseases.

ABTRACT: Background The pathogenetic and regulatory roles of natural killer (NK) and natural killer T-like cells in interstitial lung diseases (ILDs), fibrotic and granulomatous of unknown etiology are unclear. Objectives Here we investigated NK and NKT-like cells in peripheral blood (PB) and Bronchoalveolar lavage (BAL) from patients with ILDs. Method 190 patients (94 male mean age 61 ± 14.3 years) and 8 controls undergoing bronchoscopy for ILD diagnostic work-up were enrolled consecutively; 115 patients sarcoidosis, 24 chronic fibrotic hypersensitivity pneumonitis and 43 patients other ILDs [32 idiopathic pulmonary fibrosis (IPF) and 11 non-specific interstitial pneumonia (NSIP)]. PB and BAL were processed by flow cytometry using monoclonal antibodies to differentiate NK and NKT-like cells. Results NK% in BAL was significantly different among ILDs (p = 0.02). Lower NK% was observed in BAL from sarcoidosis than other ILDs (p < 0.05). Similar findings were observed for NKT-like, whereas no differences were found for PB NK%. Difference of NK% was observed between BAL and PB in all groups (p < 0.001). Sarcoidosis patients reported the best area under the curve for NKT-like (AUC = 0.678, p = 0.0015) and NK cells (AUC = 0.61, p = 0.001). In the IPF-NSIP subgroup, NK% cell was inversely correlated with FVC% (r = - 0.34, p = 0.03) and DLCO% (r = - 0.47, p = 0.0044). Conclusions NK and NKT-like were expressed differently in BAL from patients with different ILD and were significantly depleted in sarcoidosis respect to other ILDs. This suggests that these cells may play a protective role in the pathogenesis of sarcoidosis.

A functional proteomics approach to the comprehension of sarcoidosis.

Pulmonary sarcoidosis (Sar) is an idiopathic disease histologically typified by non-caseating epitheliod cell sarcoid granulomas. A cohort of 37 Sar patients with chronic persistent pulmonary disease was described in this study. BAL protein profiles from 9 of these Sar patients were compared with those from 8 smoker (SC) and 10 no-smoker controls (NSC) by proteomic approach. Principal Component Analysis was performed to clusterize the samples in the corresponding conditions highlighting a differential pattern profiles primarily in Sar than SC. Spot identification reveals thirty-four unique proteins involved in lipid, mineral, and vitamin Dmetabolism, and immuneregulation of macrophage function. Enrichment analysis has been elaborated by MetaCore, revealing 14-3-3ε, α1-antitrypsin, GSTP1, and ApoA1 as "central hubs". Process Network as well as Pathway Maps underline proteins involved in immune response and inflammation induced by complement system, innate inflammatory response and IL-6signalling. Disease Biomarker Network highlights Tuberculosis and COPD as pathologies that share biomarkers with sarcoidosis. In conclusion, Sar protein expression profile seems more similar to that of NSC than SC, conversely to other ILDs. Moreover, Disease Biomarker Network revealed several common features between Sar and TB, exhorting to orientate the future proteomics investigations also in comparative BALF analysis of Sar and TB.

Exhaled nitric oxide and carbon monoxide in lung transplanted patients.

BACKGROUND: Exhaled nitric oxide (eNO) and carbon monoxide (eCO) are markers of pulmonary inflammation associated with acute graft rejection and lung infections in lung transplant (LTX) recipients. Regarding eNO and eCO levels in LTX patients affected by bronchiolitis obliterans syndrome (BOS), published data are discordant. OBJECTIVES: We aim to evaluate eNO at multiple flows, alveolar concentration of nitric oxide (CalvNO), maximum conducting airway wall flux (J'awNO) and eCO levels in LTX patients to assess the potential role of these parameters in BOS evaluation. METHODS: Fractional exhaled nitric oxide (FeNO), CalvNO and J'awNO were analysed in 30 healthy subjects and 27 stable LTX patients (12 BOS patients). Pulmonary function tests were performed after eNO and eCO assessment. Receiver operating characteristic (ROC) curves were conducted to evaluate diagnostic accuracy for BOS of eNO parameters. RESULTS: LTX patients reported higher values of FeNO at flow rates of 50 (p < 0.01), 150 (p < 0.05), 350 ml/s (p < 0.001), and CalvNO (p < 0.0001) than healthy controls. BOS patients showed higher FeNO at flow rates of 150 (p < 0.05) and 350 ml/s (p < 0.01) and CalvNO (p < 0.001) than non-BOS patients. CalvNO reported a remarkable diagnostic accuracy for BOS (AUC: 0.82). There were no significant differences of eCO levels between LTX patients and healthy controls. CONCLUSION: LTX patients affected by BOS showed higher levels of FeNO 150 and 350, and CalvNO than non-BOS LTX patients, probably due to chronic airway inflammation and fibrotic remodelling. CalvNO may be a potential biomarker of BOS in LTX patients.

Exhaled nitric oxide in interstitial lung diseases.

Nitric oxide (NO) is a biomarker of nitrosative stress, which is involved in the pathogenesis of idiopathic interstitial pneumonias (IIP). This study evaluates exhaled NO levels in IIP patients and relates alveolar concentrations of NO (CalvNO) to pulmonary function test (PFT) and 6-minute walking test (6MWT) parameters. We measured fractional exhaled nitric oxide (FeNO), CalvNO and maximum conducting airway wall flux (J'awNO) in 30 healthy subjects and 30 patients with IIP (22 idiopathic pulmonary fibrosis and 8 idiopathic non-specific interstitial pneumonias). IIP patients had higher FeNO at flow rates of 50-100-150 ml/s and higher CalvNO levels than healthy controls (p<0.0001). CalvNO was significantly correlated with 6-minute walking distance (p<0.0001), recovery time (p<0.0005), TLC (p<0.001), FVC (p=0.01) and TLCO (p<0.01). IIP patients showed abnormal nitric oxide production, probably due to lung fibrosis and oxidative-mediated lung injury. CalvNO was correlated with PFT and 6MWT parameters and is proposed as a potential biomarker of lung fibrosis and exercise tolerance.

Serum analysis of coagulation factors in IPF and NSIP.

Recent literature and our previous proteomic findings prompted us to study the coagulation system in idiopathic pulmonary fibrosis (IPF), the pathogenesis of which remains unclear. The aim of this study was to compare coagulation factors in idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia (NSIP) patients and healthy controls. Thirty-three IPF patients (23 acute exacerbation and 10 stable IPF patients), 7 NSIP patients, and 44 controls were enrolled. Concentrations of D-dimer, homocysteine, functional protein C, protein C antigen, free and total protein S antigen and activity, fibrinogen and factor VIIIc were analyzed in serum of patients and controls. The lupus anticoagulant (LAC) test was also performed. Factor VIIIc levels were significantly higher in acute exacerbation IPF patients than controls (p = 0.0001) and in stable IPF patients than controls (p = 0.002). Factor VIIIc levels were higher and PT levels were lower in acute exacerbation IPF patients who died after exacerbation than in patients who survived (p = 0.04 and p = 0.003, respectively). D-dimer, fibrinogen, and homocysteine levels were also significantly higher in IPF patients than controls (p < 0.01). Protein C activity was increased in acute exacerbation IPF patients than controls (p = 0.005). The LAC test was positive in seven IPF patients and negative in controls. Procoagulant status was demonstrated in IPF patients (mainly in acute exacerbation/IPF) than controls and NSIP patients, probably due to endothelial activation and microvascular injury. These preliminary results are of interest because of their potential implications in the pathogenesis and treatment of this disease.

Pulmonary hypertension in idiopathic pulmonary fibrosis: prevalence and clinical progress.

The aims of the present study are to define the prevalence of pulmonary hypertension (PH) in a cohort of idiopathic pulmonary fibrosis (IPF) patients, to investigate any correlations between systolic pulmonary artery pressure (PAPs) and functional data, to evaluate clinical progress and to compare long-term survival in IPF patients with and without PH. A population of 126 IPF patients was recruited. A high prevalence of PH (39.7%, 50/126), evaluated by echocardiography on the basis of PAPs greater than 36 mmHg, was mainly observed in smokers and female patients. Regression analysis revealed a significant correlation between PAPs greater than 50 mmHg and DLCO/VA (p = 0.0294). Mean PAPs was significantly greater one year after onset of PH (p = 0.01). 11/21 patients with FVC less than 50% had a significant increase in PAPs one year after onset of PH (p = 0.02). There was a highly significant difference between survival of IPF patients with and without PH (p = 0.0001; hazard ratio = 3.56). This study revealed that PH has a high prevalence in patients with IPF and is associated with increased risk of mortality. Early diagnosis of IPF patients with pulmonary hypertension is important, so that they can be enrolled in waiting lists for lung transplant as soon as possible.

Utility of spiral CAT scan in the follow-up of patients with pulmonary Langerhans cell histiocytosis.

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare disease that occurs almost exclusively in smokers, generally young adults between 20 and 40 years old. Prognostic biomarkers of the disease are lacking. This study describes the clinical-radiological features of a group of PLCH patients and applies a semi-quantitative CT score of the chest to verify the prognostic value of radiological findings in this disease. Clinical-radiological and immunological data from 12 Caucasian patients (6M, 7 smokers and 5 ex-smokers, mean age 36±8 years) were recorded at onset and after a follow-up period of 4 years. Application of the semi-quantitative CT score revealed a prevalently cystic pattern at onset and follow-up in the majority of the patients. Patients with a prevalently nodular pattern developed cystic lesions during follow-up. Interestingly, significant correlations were found between the extent of cystic lesions and DLCO values at onset (time 0: p<0.05) and at the end of follow-up (time 1, p<0.05) and with FEV1 values at time 0 (p<0.05) and time 1 (p<0.05). Patients with progressive functional decline were those with CT evidence of severe cystic alterations. The results suggest that high resolution CT scan of the chest is mandatory for characterizing PLCH patients at diagnosis and during follow-up. The proposed CT score of the chest showed potential prognostic value.

Exhaled carbon monoxide in sarcoidosis.

BACKGROUND: Exhaled Carbon monoxide has been proposed as a non-invasive marker in several inflammatory diseases of the lung, but no data are available in patients with sarcoidosis. METHODS: We evaluated the levels of exhaled CO in 78 nonsmoker patients with sarcoidosis and we compared the results with 25 healthy non smoker controls, of 25 patients with a variety of interstitial lung diseases, and 77 smokers. RESULTS: Mean value of exhaled CO in sarcoidosis was 3.3 (2.9-3.8) ppm (GM with 95% CI in parenthesis), resulting significantly higher than both normal controls, 1.4 (1.2-1.7) ppm (p<0.001), and clinical controls, 2.1 (1.7-2.7) ppm (p<0.02). All these levels, however, were markedly lower than those observed in smokers, 14.6 (12.7-16.9) ppm. No correlation was found with radiological stage, steroid therapy, respiratory function, or serum ACE activity. Using an upper normal value of 4 ppm, an increased level of exhaled CO was found in 50% of patients with sarcoidosis, in 24% of clinical controls, and in 97% of smokers. CONCLUSIONS: Our data indicate that significant release of endogenous CO occurs in sarcoidosis. It is unlikely that the measurement of exhaled CO could be of diagnostic usefulness, due to its low specificity and to the possible influence by occasional or passive smoke.

Different effects of inhaled aspirinlike drugs on allergen-induced early and late asthmatic responses.

Little is known about the anti-asthmatic effects of powerful anti-inflammatory agents such as aspirin-like drugs. We compared the effects of two aspirin-like drugs with different pharmacologic activities, sodium salicylate (SSA) and indomethacin, with the effect of lysine acetylsalicylate (LASA), inhaled 30 min before challenge, on the early and the late asthmatic response induced by a single dose of allergen causing a 25% decrease in FEV1 in a preliminary challenge. Inhaled SSA partially prevented both the early and late response, providing a protection with respect to placebo of 22 +/- 6% in the early phase and 23 +/- 9% in the late phase of the response. These values were lower (but not significantly) than those of LASA (41 +/- 9% and 39 +/- 11%, respectively). In a second group of patients, indomethacin failed to affect the early response, while LASA provided a protection of 31 +/- 7%. However, these two drugs were equally effective in reducing the late response (44 +/- 18% and 39 +/- 17% protection for LASA and indomethacin, respectively). In subjects with an early response, despite being ineffective in preventing allergen-induced bronchoconstriction, indomethacin blocked the allergen-induced increase in bronchial hyperresponsiveness measured 2 h after challenge. We conclude that inhaled salicylates, but not indomethacin, exert a protective activity against the early allergic response. This difference is not explained by the different pattern of cyclooxygenase inhibitory activity of these drugs.

Protective effect of inhaled lysine acetylsalicylate on allergen-induced early and late asthmatic reactions.

Conflicting results have been reported on the effect of non-steroidal antiinflammatory drugs on allergen-induced asthmatic responses. The aim of this study was to investigate the effect of inhaled lysine acetylsalicylate (LASA) on the early and late allergen-induced responses. We studied 16 patients with mild, stable asthma who had an early asthmatic response and 10 patients with a dual (early and late) response. Each patient underwent two challenges with a single dose of allergen assessed in a preliminary test, after inhalation of either 720 mg of LASA in 4 ml of saline solution or placebo, according to a randomized, double-blind protocol. Allergen-induced hyperreactivity to methacholine was measured in six patients from each of the early and the dual response groups 2 hours and 24 hours after the challenge, respectively. In the patients with early response, the maximum fall in FEV1 after challenge was 24% +/- 1% after inhalation of placebo and 14% +/- 2% after inhalation of LASA (p < 0.005). No protection was observed in four patients who received the drug orally instead of by inhalation. In the patients with a dual response, the maximum FEV1 decrease during the early response was 27% +/- 2% after placebo and 21% +/- 2% after LASA (p < 0.025). During the late response (between 3 and 8 hours), the maximum decrease in FEV1 was 28% +/- 4% after placebo and 16% +/- 4% after LASA (p < 0.005). In both groups allergen challenge caused a significant reduction in methacholine PD20 after treatment with placebo but not with LASA. Without allergen challenge, LASA had no effect on methacoline reactivity. We conclude that inhaled LASA significantly reduces both the early and the late asthmatic response to allergen challenge and that it prevents the allergen-induced airway hyperresponsiveness that follows these responses.

Attenuation of aspirin-induced bronchoconstriction by sodium cromoglycate and nedocromil sodium.

The protective activity of nedocromil sodium and of sodium cromoglycate against aspirin-induced asthma has never been investigated in controlled studies. Because it has been reported that aspirin-induced platelet-mediated cytotoxic activity in vitro is inhibited after treatment in vivo with nedocromil but not with cromoglycate, we investigated whether these compounds also exhibit a different protective activity against aspirin-induced bronchoconstriction. Ten patients with aspirin-induced asthma underwent three bronchial challenges with a single dose of lysine acetylsalicylate (LASA) that caused a decrease in FEV1 of 25% or more in a preliminary dose-response test 30 min after inhalation of 4 mg nedocromil sodium, 10 mg sodium cromoglycate, or placebo. FEV1 and SRaw were recorded at intervals for 195 min. After placebo, LASA caused a maximal decrease in FEV1 of 42 +/- 4% of baseline. After cromoglycate and nedocromil the maximal decrease in FEV1 was reduced to 20 +/- 3% and 18 +/- 4%, respectively (p < 0.01 versus placebo for both treatments), without significant differences between the two treatments. Similar results were observed with SRaw. We conclude that, at the recommended therapeutic doses, sodium cromoglycate and nedocromil sodium are equally effective in attenuating aspirin-induced bronchoconstriction and that it is unlikely that platelet activation participates in the pathogenesis of aspirin-induced asthma.

Inhaled PGE2 prevents aspirin-induced bronchoconstriction and urinary LTE4 excretion in aspirin-sensitive asthma.

Bronchial overproduction of leukotrienes and inhibition of prostaglandin synthesis are involved in the pathogenesis of aspirin-induced asthma. We investigated whether inhaled prostaglandin E2 (PGE2) attenuates the response to bronchial challenge with lysine acetylsalicylate (LASA) and the associated increase in urinary leukotriene E4 (u-LTE4) in seven aspirin-sensitive subjects with asthma. Each subject performed two challenges with a single dose of LASA that caused a decrease in FEV1 of 20% or more in a preliminary test, immediately after inhaling 100 micrograms PGE2 in 4 ml saline or placebo, according to a randomized double-blind protocol. FEV1 was recorded at 30-min intervals for 4 h. u-LTE4 was measured by combined high-performance liquid chromatography enzyme immunoassay at 2-h intervals. After placebo, LASA caused an obstructive reaction in all patients, with a maximum decrease in FEV1 of 35 +/- 5% with respect to baseline. u-LTE4 rose from 911 +/- 261 picograms (pg)/mg creatinine at baseline to a maximum value of 2249 +/- 748 after challenge. Inhaled PGE2 provided almost complete protection in all patients. Baseline u-LTE4 was 883 +/- 243 pg/mg creatinine and did not change significantly during the test, reaching a maximum value of 864 +/- 290 (p < 0.05 versus placebo). These results confirm that PGE2 is highly effective in preventing aspirin-induced asthma and suggest that this effect is mediated by inhibition of sulfidopeptide leukotriene production.

Steroid-sparing effect of inhaled lysine acetylsalicylate and furosemide in high-dose beclomethasone-dependent asthma.

BACKGROUND: Inhaled lysine acetylsalicylate and furosemide exert a mutually potentiating protective activity on experimentally induced bronchoconstriction in asthma. OBJECTIVE: Our purpose was to investigate the clinical effectiveness of combined treatment of asthma with inhaled lysine acetylsalicylate and furosemide. METHODS: We performed a randomized, double-blind, crossover study in nine patients with chronic asthma requiring a high dose (2 mg/day) of inhaled beclomethasone for clinical control. Patients were treated with a combination of 720 mg inhaled lysine acetylsalicylate and 40 mg furosemide twice daily, or with matched placebo in addition to inhaled steroids. The dose of inhaled steroids was reduced by half every 15 days and eventually suspended unless a patient's respiratory condition worsened. RESULTS: During treatment with placebo, all patients had worsening of asthma at dosages of 1 or 0.5 mg/day beclomethasone (mean +/- SE, 833 +/- 83 micrograms/day). During combined treatment complete suspension of inhaled steroids in two patients and reduction to 0.5 to 0.25 mg in the remaining seven patients (mean, 250 +/- 72 micrograms/day) was achieved, with a mean reduction of 71% +/- 7%. Forced expiratory volume in 1 second, weekly peak expiratory flow rate, symptom score, and bronchodilator intake remained significantly better with combined treatment than with placebo. CONCLUSIONS: Treatment with inhaled lysine acetylsalicylate and furosemide allows a considerable sparing of inhaled steroids without significant side effects in patients with severe asthma.

Time-limited protective effect of inhaled frusemide against aspirin-induced bronchoconstriction in aspirin-sensitive asthmatics.

Inhaled frusemide effectively prevents the bronchial obstructive response to allergens and to a number of nonallergic stimuli. In most of the experimental models in which it has been tested, the protective effect of frusemide has been evaluated for only a short time after administration. In aspirin-sensitive patients, acetylsalicylic acid causes an asthmatic reaction which typically lasts for 2 h or more after exposure. We investigated the presence and duration of the protective effect of inhaled frusemide against the bronchial response to aspirin in sensitive patients, using a specific inhalation challenge with lysine acetylsalicylate (LASA). In the first study, eight subjects with aspirin-asthma underwent two bronchial challenges with a single dose of lysine acetylsalicylate administered through a jet nebulizer, after treatment with 40 mg inhaled frusemide or placebo, according to a randomized, double-blind protocol. Forced expiratory volume in one second (FEV1) was monitored for 120 min after challenge. In the second study in eight patients, the protocol was modified by the use of a dosimeter for delivery of lysine acetylsalicylate, by reducing the dose of lysine acetylsalicylate to avoid intense reactions, and by extending the follow-up to 4 h. In the first study, after placebo, FEV1 gradually decreased, reaching a maximum decrement of 39 +/- 3% at 120min. Inhaled frusemide exerted a significant protection at all time-points, although this activity appeared to decrease with time. In the second study, after placebo, inhaled lysine acetylsalicylate caused a gradual decrease in FEV1, which reached a maximum decrement at 180 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of the antireactive, antiasthmatic effect of inhaled furosemide by inhaled lysine acetylsalicylate.

Nonsteroid antiinflammatory drugs interfere with the diuretic activity of furosemide, implying that this effect is at least partially dependent on renal prostaglandin synthesis. To investigate whether prostaglandin production could also modulate the bronchial antireactive activity of this diuretic drug, we investigated the effect of inhaled lysine acetylsalicylate (162 mg) and of furosemide (18 mg), alone and in combination, on the bronchial obstructive response to ultrasonically nebulized water in asthmatic patients. The study was also prompted by the conflicting results obtained in previous studies of oral nonsteroid antiinflammatory drugs. Fifteen asthmatic patients underwent bronchial challenge with a mist of ultrasonically nebulized distilled water at the same time of day on four occasions, 2-4 days apart, 15 min after premedication according to a double-blind, randomized protocol. After placebo, mean PD15 to water mist did not differ from a preliminary test (2.1 +/- 0.2 and 2.5 +/- 0.4 ml, M +/- SE, respectively). After lysine acetylsalicylate, mean PD15 rose to 5.0 +/- 0.7 ml (2.8 +/- 0.6 times higher than placebo); after furosemide, to 9.0 +/- 1.5 ml (4.4 +/- 0.9 times over placebo); and after the two drugs in combination, to 32.2 +/- 5.6 ml (16.3 +/- 3.0 times higher than placebo). Similar results were obtained with inhaled indomethacin, whereas sodium salicylate had no effect. These data indicate that the bronchial antireactive activity of inhaled furosemide is greatly enhanced by inhaled lysine acetylsalicylate through a mechanism which probably involves inhibition of the local synthesis of prostaglandins, and could have therapeutic implications.

Inhaled loop diuretics as potential new anti-asthmatic drugs.

The observation that changes in bronchial osmolarity can induce bronchoconstriction in asthma inspired the experimental studies which, unexpectedly, revealed that frusemide is an effective bronchoprotective agent against a variety of osmotic and non osmotic stimuli. Although the mechanism of this protective effect is not fully understood, studies in vivo and in vitro suggest that frusemide may inhibit the activation of different cell types induced by bronchoconstrictor stimuli. Other loop diuretics also exert bronchoprotective activity, but frusemide appears to be the more effective bronchoprotective agent of this family, regardless of their diuretic potency and lipid solubility. Despite the relatively large amount of experimental evidence, there is currently little information on the clinical effectiveness of frusemide in asthma and a long-term controlled study is currently in progress. The observations that treatment with a combination of inhaled acetylsalicylate and frusemide results in a markedly increased bronchoprotective effect compared to either drug alone, opens a new perspective in the possible clinical use of these drugs. Preliminary studies suggest that the association of these drugs is well tolerated and may result in a remarkable steroid sparing effect in patients with steroid dependent asthma, for whom a convenient alternative to long-term steroid therapy is not currently available.