Beneficial role of L-arginine in cardiac matrix remodelling in insulin resistant rats.

BACKGROUND: The study was performed to determine whether sucrose-induced insulin resistance could increase the expression of cardiac matrix metalloproteinases (MMPs), indices of matrix remodelling, and whether the addition of 1.25 g day(-1) of L-arginine (ARG) to a sucrose diet could prevent both the sucrose-induced metabolic abnormalities and elevated cardiac expression of matrix metalloproteinases in an insulin resistant stage that precedes frank type 2 diabetes. MATERIALS AND METHODS: Experiments were performed on 38 male Sprague-Dawley rats, 16 rats maintained a standard chow diet (ST), 12 rats were switched to a sucrose enriched diet (SU) and 10 rats to a sucrose plus L-arginine (1.25 g day(-1)) enriched diet (SU + ARG) for a period of 8 weeks. After 8 weeks of different diets, an intravenous glucose tolerance test (IVGTT) was performed and samples were drawn for the measurements of insulin, glucose, triglycerides, free fatty acids (FFA), plasma cyclic guanosine-monophosphate (c-GMP) and retroperitoneal, omental, epididymal fat pad and heart were dissected and weighed. RESULTS: At the end of the study, retroperitoneal fat, heart weight/body weight ratio, fasting plasma glucose, serum insulin, and serum triglyceride levels and integrated insulin area after IVGTT were significantly higher in SU than in SU + ARG and ST. All these parameters were comparable between SU + ARG and ST animals. FFA levels were significantly different among groups, with highest levels in SU and lowest levels in ST. Fasting plasma c-GMP levels and the integrated c-GMP area after IVGTT, an index of nitric oxide activity, were significantly lower in SU than in SU + ARG and ST, the result was similar in SU + ARG and in ST MMP-9 protein expression increased 10.5-fold, MMP-2 protein expression increased 2.4-fold and the expression of tissue inhibitors of metalloproteinase (TIMP-1) increased 1.7-fold in SU rats as compared to ST animals. This was accompanied with a significant increase of cardiac triglyceride concentrations. In contrast, cardiac MMP-9, MMP-2, and TIMP-1 protein expressions were not different between SU + ARG and ST animals. Cardiac triglyceride levels were not significantly different between SU + ARG and ST rats. CONCLUSIONS: SU rats developed insulin resistance and hyperlipidaemia, accompanied with increased fat deposition in the heart and enhanced MMP protein expression. Conversely, ARG supplementation prevents these metabolic abnormalities and restored MMP/TIMP-1 balance.

Relationship between ARIA classification and drug treatment in allergic rhinitis and asthma.

INTRODUCTION: The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines provide a stepwise treatment to rhinitis, which classifies the disease according to its duration and severity. OBJECTIVES: The aim of the study was to verify whether these variables influence drug prescriptions for rhinitis and asthma. METHODS: A multi-centre cross-sectional pharmaco-epidemiological survey was carried out on 1,610 allergic rhinitis patients and the relationship between the clinical features of rhinitis and drug therapy for rhinitis and asthma was evaluated. RESULTS: A total of 1,321 adult patients were enrolled. Mild intermittent rhinitis was diagnosed in 7.7%of the patients, moderate/severe intermittent in 17.1%, mild persistent in 11.6%, and moderate/severe persistent in 63.6%. A high level of rhinitis-asthma comorbidity (616/1,321 = 46.6%) was found. The majority of patients [1,060 (80.24%)] were treated. Significant associations between the severity of rhinitis and the presence of therapy (P = 0.008), the use of oral antihistamines (P < 0.001), topical nasal steroids (P = 0.020) and systemic steroids (P = 0.005) were found. A weak association was found between the features of rhinitis and the therapy for asthma, and vice versa the comorbidity with asthma increases the prescription of inhalant (P < 0.001) and oral steroids (P = 0.015) to treat rhinitis. CONCLUSION: The severity of rhinitis influences patient request for rhinitis therapy and the type of medication more than the duration. These features of rhinitis seem to poorly influence asthma therapy. As the ARIA classification is able to reveal a relevant impairment notwithstanding therapy, its role in treated patients merits further study.

Degree of control of physician-diagnosed asthma and COPD in Italy.

BACKGROUND: It is important for the Italian National Health Service to obtain data on the degree of control of asthma and chronic obstructive pulmonary disease (COPD) in the general population in Italy in order for balanced planning of future investments in these diseases to be made. Currently, precise estimates of these parameters are not available in literature. OBJECTIVES: In collaboration with the Italian Academy of General Practitioners (SIMG; www.simg.it) we have investigated the degree of control of physician-diagnosed asthma and COPD in Italy. METHODS: A standardised questionnaire on asthma and COPD has been self-administered to a sample of 1937 Italian family physicians (representing around 5% of all the Italian doctors involved in general practice) chosen to cover all the Italian counties. RESULTS: We have collected questionnaire data from 19,917 patients with asthma and COPD followed in their practice and 12,438 (62.4%) were correctly filled in enabling evaluation. We selected the number of emergency room visits, hospitalisations and intensive care unit admissions for asthma and COPD in the last 12 months as objective measures of the degree of asthma and COPD morbidity in these patients. The figures were respectively 12.4% (emergency room visits), 17.3% (hospitalisations) and 1.2% (intensive care unit admissions) of all patients with physician-diagnosed asthma and COPD. CONCLUSIONS: This data suggests that in Italy the morbidity of asthma and COPD remains high; representing a significant burden for the Italian National Health Service. There is a clear necessity for further studies to investigate the causes of this incomplete control.

Allergic rhinitis and asthma comorbidity: ARIA classification of rhinitis does not correlate with the prevalence of asthma.

BACKGROUND: Allergic rhinitis and asthma comorbidity is supported by both the similar underlying pathogenesis and immunologic mechanisms. The aim of this study was to verify whether the characteristics of rhinitis classified according to the new Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines correlate with the prevalence of asthma. METHODS: From 1 March to 30 June 2002, a multi-centre cross-sectional study was conducted by 154 allergists chosen from throughout Italy. Duration, severity of rhinitis (according to the ARIA classification) and the type of allergic sensitizations were compared with the prevalence of asthma. RESULTS: One thousand three hundred and twenty-one consecutive rhinitis-allergic patients aged 18 years or older were enrolled for the study. The majority of patients, 1060 (80.24%), were on medication at the time of their specialist visit. Mild intermittent rhinitis was diagnosed in 7.7% of patients, moderate/severe intermittent in 17.1%, mild persistent in 11.6%, and moderate/severe persistent in 63.6%. The prevalence of asthma was 48% in patients with mild intermittent rhinitis, 49.6% in moderate-severe intermittent rhinitis, 36.6% in mild persistent rhinitis and 47.5% in moderate severe persistent patients. No correlation between the ARIA categories of rhinitis and the prevalence of asthma was found. A multivariate analysis, after adjustment for age, sex, type of sensitization, level of severity and duration of rhinitis classified according to the ARIA guidelines, demonstrated that age, over 41 years [risk ratio (RR) 1.260, 95% confidence interval (CI) 1.072-1.482] and especially over 51 years (RR 1.460, 95% CI 1.237-1.723), sensitization to indoor allergens (mite and cat), (RR 1.203, 95% CI 1.060-1.366), and polysensitization (RR 1.178, 95% CI 1.004-1.383) are significant risk factors for asthma. CONCLUSION: In allergic rhinitis (AR) patients referred to a specialist, the features of AR as defined by the ARIA classification are not able to predict the presence of asthma, therefore all such patients should be assessed for asthma.

Effects of low doses of inhaled fluticasone propionate on inflammation and remodelling in persistent-mild asthma.

In asthma a dysregulation of eosinophil apoptosis and an imbalance of metalloproteinase-9 (MMP-9) and tissue inhibitor metalloproteinase-1 (TIMP-1) play an important role in airway inflammation and remodelling. We evaluated the effects of a low dose of inhaled fluticasone proprionate (FP) (100 microg bid by Diskus) for 4 weeks in 24 steroid naive patients with mild persistent asthma, symptomatic and with a sputum eosinophilia >or=3% on clinical outcomes and inflammatory markers such as the induced sputum eosinophils, the induced sputum apoptotic eosinophils, the levels of MMP-9 and TIMP-1 and their molar ratio in the induced sputum supernatants. After FP treatment forced expiratory volume (FEV1) and FEV1/forced vital capacity values, PEF (L/min), sputum apoptotic eosinophils, and MMP-9/TIMP-1 molar ratio in sputum supernatants of asthmatic subjects were significantly increased in comparison with baseline, while sputum eosinophils significantly decreased. Change (Delta) in FEV1 after treatment with FP negatively correlated with the Delta in sputum eosinophils, while the Delta in MMP-9 values positively correlated with Delta in TIMP-1 values. This study shows that the clinical improvement achieved by the use of low doses of FP in asthmatics is related, at least in part, to the resolution of eosinophilic inflammation and the downregulation of remodelling markers.

Rhinitis in pre-school children: prevalence, association with allergic diseases and risk factors.

BACKGROUND: The aim of our study was to assess the prevalence of rhinitis, sneezing, runny or blocked nose apart from colds in a pre-school children population and to evaluate the risk factors and relationship with allergic diseases and sensitization. METHODS: Eighteen nursery schools were randomly selected. The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire (WQ) was distributed and filled by parents of pre-school children (3-5 years). The allergic sensitization to common aeroallergens and foods was evaluated by skin prick test (SPT). chi2 tests were used to compare proportions between rhinitic and non-rhinitic children. RESULTS: One thousand four hundred and two (92%) valuable questionnaires were returned. Prevalence of rhinitis in the last 12 months was 16.8%. Rhinitic children compared to non-rhinitic children presented a significant increase of diagnosed asthma (20.8% vs. 6.2%, P<0.001), lifetime wheezing (43.2% vs. 21.6%, P<0.001), wheezing in the last 12 months (25.0% vs. 9.4%, P<0.001), atopic dermatitis (22.9% vs. 13.9%, P<0.001) and allergic sensitization (29.9% vs. 13.7%, P<0.001). Sensitization to grass pollen and house dust mites were significant risk factors for rhinitis (P<0.01). A family history of atopy, having pets at home, male gender and greater age were significant risk factors for rhinitis, but not smoking exposure, sharing a bedroom or breastfeeding. CONCLUSIONS: In pre-school children rhinitis has a strong association with wheezing symptoms, asthma and atopic dermatitis. Allergic sensitization is a risk factor for rhinitis and should be evaluated even in pre-school children.

Cytokine release and adhesion molecule expression by stimulated human bronchial epithelial cells are downregulated by salmeterol.

Summary beta2-adrenoreceptor agonists are able to modulate various aspects of airway cell functions involved in the inflammatory and repair processes characterizing a variety of respiratory disorders. Human bronchial epithelial cells (HBECs), which can act as immune effector cells and express beta2-adrenoreceptors, were used to test the effects of different concentrations (0.1-100.0 nM) of salmeterol (Salm) on adhesion molecule expression and chemokine/cytokine release. HBECs, freshly isolated from resected bronchi at the time of surgery in ex-smokers with lung cancer, constitutively expressed over 3 times more ICAM-1 than VCAM-1 (P<0.05) and secreted greater amounts of IL-8 than of GM-CSF or RANTES (P<0.001). Stimulation of HBECs with IL-4, TNF-alpha or IL-4 plus TNF-alpha-upregulated ICAM-1 expression (P<0.05) and increased GM-CSF and IL-8 secretion (P<0.05). Similarly, VCAM-1 expression was significantly increased by IL-4 plus TNF-alpha, while RANTES release was significantly enhanced by IL-4 or by IL-4 plus TNF-alpha (P<0.05), but not by TNF-alpha alone (P>0.05). Dose-response curves showed that Salm, at concentration >1.0 nM, was effective in inhibiting adhesion molecule expression and cytokine release by HBECs (P<0.05). At a Salm concentration of 10 nM the degree of inhibition observed was similar for ICAM-1 and VCAM-1 expression (37.2 +/- 9.3% and 32.9 +/- 9.6%, respectively; P>0.05), but higher for RANTES (88.4 +/- 4.4%), as compared to IL-8 (21.8 +/- 7.0%) or GM-CSF (30.1 +/- 6.6%; P<0.05, each comparison). Thus, adhesion molecules and cytokines may be expressed/released at very different levels by unstimulated or stimulated HBECs and those activities appear to be modulated by Salm.

Asthma prevalence and drug prescription in asthmatic children.

A cross-sectional study was conducted on among 28,856 children aged from birth to 14 years to determine the prevalence of asthma and assess its treatment in a sample of asthmatic children. Children diagnosed with asthma were identified by a sensitive algorithm applied to the information stored in the computerized medical records between 1997 and 1998. Pediatricians then reviewed and validated the diagnosis. Specific information was obtained, after age stratification under 5 yrs and over 6 ys, from the medical records and by interview regarding their personal details and treatment of asthmatic patients. In all, 1,263 cases of asthma were identified (64% males) with a prevalence of 6.3% among males and 4% among females in under 5 year-olds, and 3.9% for males and 2.1% for females in over 6 year-olds. The prevalence of asthma diagnosed directly by the pediatrician was consequently higher among under 5 year-olds, in both genders, than among the older children. Contrary to the international guidelines, pediatricians prescribed more oral corticosteroids and nebulized short-acting beta-2 agonists for children under 5 ys olds than for over 6 year-olds (13.3% Vs 4.8% and 25% Vs 10.9%, respectively, p < 0.001). For the > or = 6 year-olds, the most commonly prescribed treatments were oral antihistamines (13.9% Vs 12.6%), inhaled corticosteroids via metered-dose inhaler (30.8% Vs 28.7%) and sodium cromoglycate (12.1% Vs 4.8%, p < 0.001).

Effects of in vitro treatment with fluticasone propionate on natural killer and lymphokine-induced killer activity in asthmatic and healthy individuals.

BACKGROUND: Topical corticosteroids are beneficial in the treatment of allergic respiratory disorders; they exert effects on a number of cells involved in allergic inflammatory reactions. On the other hand, major histocompatibility complex (MHC)-unrestricted cytotoxicity (i.e., natural killer [NK] cell activity) may play a role in the inflammatory allergic reaction. The objective was to gain insight into the mechanisms of the therapeutic effects of fluticasone propionate (FP), an inhaled corticosteroid used in asthma and rhinitis therapy. Therefore, we evaluated the NK and lymphokine-activated killer (LAK) activity of effector cells in vitro treated or not with FP. METHODS: Evaluations were made on peripheral blood mononuclear cells (PBMNCs), obtained from healthy volunteers (n = 10) and from asthmatic atopic subjects (n = 10) with allergy to Parietaria. RESULTS: Asthmatic patients had significantly increased NK activity (P= 0.0008), and interleukin (IL)-2- (P=0.0005) and interferon (IFN)-alpha-induced LAK activities (P=0.0005). In both groups, FP 10(-7) M significantly reduced NK activity (P<0.0001), IL-2-induced LAK activity (P<0.0001), and IFN-alpha-induced LAK activity (P<0.0001). Similar results were obtained with FP 10(-8) M. CONCLUSIONS: Since MHC-unrestricted cytotoxicity has been implicated in the development of allergen-induced eosinophilic airway inflammation, inhibition of NK and LAK activity by FP may contribute to the steroid therapeutic effect in asthma.

Cytotoxicity, cellular uptake and DNA binding of the novel trinuclear platinun complex BBR 3464 in sensitive and cisplatin resistant murine leukemia cells.

BBR 3464 is a novel trinuclear platinum anticancer agent designed on the hypothesis that new clinically useful platinum based anticancer agents should have novel structures unrelated to those of agents currently used in the clinic. BBR 3464 shows outstanding cytotoxicity both against sensitive (L1210) and cisplatin (CDDP) resistant (L1210/CDDP) murine leukemia cell lines. In fact, BBR 3464 is 30 times more cytotoxic than CDDP against the L1210 cell line and also shows a complete lack of cross-resistance in L1210/CDDP (resistance index 0.8). BBR 3464 and CDDP cellular uptake in L1210 and L1210/CDDP eells and binding to nuclear DNA were studied after incubation with 3.34 microM BBR 3464 and 66.7 microM CDDP, respectively, for up to 4 hours with 133.4 and 266.8 microM of CDDP and 6.68, 13.36 microM of BBR 3464 for 2 hours to determine concentration-cellular uptake and concentration-DNA binding relationships. CDDP and BBR 3464 cellular uptake and their extent of binding to DNA increased as function of time and in a concentration dependent manner in both cell lines. CDDP uptake and binding to DNA were higher in L1210 eells than in L1210/CDDP cells whereas BBR 3464 uptake and binding to DNA were similar in both cell lines. In L1210/CDDP murine leukemia cells BBR 3464 seems to overcome the CDDP cross-resistance related to impaired accumulation and reduction of binding to DNA.

The effects of toluene diisocyanate and of capsaicin on human bronchial smooth muscle in vitro.

Toluene diisocyanate contracts guinea-pig bronchial smooth muscle through a mechanism involving capsaicin-sensitive sensory nerves. In the present study, we investigated the effects of toluene diisocyanate, capsaicin and tachykinins on isolated human bronchi. In 44 rings, toluene diisocyanate (0.3 mM) produced a relaxation which averaged 16.9 +/- 1.1%, in ten rings it produced a shortening that was 15.1 +/- 3.3% and in ten preparations it gave no response. A second administration of toluene diisocyanate (0.3 mM) always produced a relaxation (n = 13, 18.1 +/- 3.9%). Capsaicin (0.03 mM) produced shortening in 15 (35 +/- 6.6%) and relaxation in 11 preparations (41 +/- 6.8%), whereas a second administration caused shortening in nine (25.1 +/- 6.1%) and relaxation in 16 rings (36.4 +/- 4.9%). When toluene diisocyanate was given after two consecutive capsaicin administrations, we observed shortening in two rings (10.0 +/- 3.6%), relaxation in ten rings (15.9 +/- 3.6%), and no response in four preparations. To test the role of NK1 and NK2 receptors in these conflicting responses, we performed concentration-response curves to different tachykinins. Substance P, neurokinin A and neurokinin A-(4-10), a specific NK2 receptor agonist, gave a concentration-dependent shortening, with neurokinin A being the most effective and neurokinin A-(4-10) the least. The specific NK1 receptor agonist, [Sar9, Met(O2)11]substance P, produced both shortening and relaxation. We conclude that toluene diisocyanate and capsaicin may produce both shortening and relaxation in isolated human bronchi through NK1 receptors.

Steady-state dependence of stress on cross-bridge phosphorylation in the swine carotid media.

Tonic contractions of the swine carotid media are typically characterized by initial transients in myoplasmic [Ca2+] and cross-bridge phosphorylation followed by force maintenance with reduced intracellular [Ca2+] and cross-bridge phosphorylation ("latch"). The presence of effective mechanisms in the carotid media to limit steady-state myoplasmic [Ca2+] and cross-bridge phosphorylation to modest increases over resting values has limited experimental attempts to determine the dependence of active stress (force/tissue cross-sectional area) on cross-bridge phosphorylation. In this study, we employed stimulation protocols that combined effective contractile agonists with inhibitors of Ca2+ extrusion or sequestration to achieve high steady-state levels of cross-bridge phosphorylation (up to 60%). Increases in cross-bridge phosphorylation from 30 to 60% were not associated with significant increases in stress in agreement with the predictions of Hai and Murphy [Am. J. Physiol. 254 (Cell Physiol. 23): C99-C106, 1988] four-state cross-bridge model for the carotid media. Thus cross-bridge phosphorylation may suffice to determine force generation in vascular smooth muscle if both phosphorylated and dephosphorylated attached cross bridges (or latch bridges) contribute to active stress.

Response to acetylcholine and myosin content of isolated canine airways.

Contractility of tracheal smooth muscle strips and spiral strips of fourth to fifth generation bronchi was studied in organ baths. The relationship among contractility, airway smooth muscle myosin, and smooth muscle thickness was also examined. The trachea was divided into three segments, each consisting of 12-14 rings. Smooth muscle strips from each of the three regions (top, middle, and bottom of the trachea) and from fourth to fifth generation bronchi were studied. Acetylcholine (ACh) sensitivity (-log EC50) was 8.1, 7.1, 7.9, and 6.1 for the top, middle, and bottom of the trachea and the bronchi, respectively. At P = 0.01, the EC50 ACh value of the top of the trachea differed from the EC50 value of the bronchi. Maximal tension (Tmax) generated in bronchi (3.2 g) was lower (P less than 0.01) than in the top (10.4 g), middle (7.1 g), and bottom of the trachea (5.1 g). Differences between trachea and bronchi disappeared when Tmax was corrected for smooth muscle myosin content. Thickness of smooth muscle in bronchi was less (P less than 0.01) than in the three regions of trachea. Tmax was significantly correlated with airway smooth muscle thickness (r = 0.56; P less than 0.05). These results suggest that in mongrel dogs sensitivity to ACh shows a gradient from the top of the trachea to the bronchi and that Tmax is greater in the trachea than in the bronchi and is significantly correlated with thickness of smooth muscle.

Airway smooth muscle biochemistry and asthma.

The contractile properties of muscle cells are related to the molecular structure of myosin. The molecular structure and the antigenicity of myosin isoforms is different in skeletal, cardiac, and smooth muscle. We investigated whether different isoforms of myosin heavy chains are present in smooth muscle from human lungs. We observed that the distribution of three isoforms of smooth muscle myosin heavy chains is different in airways compared to pulmonary arteries, and in central airways and arteries compared to lung parenchyma. We also observed that asthmatic subjects have a similar distribution, but different immunoreactivity of myosin heavy chains in bronchial smooth muscle compared to normal subjects. These data suggest that changes in the contractile properties of smooth muscle in human lungs may be associated with changes in myosin heavy chain isoforms.