IgE sensitization to food allergens and airborne allergens in relation to biomarkers of type 2 inflammation in asthma.

BACKGROUND: We have recently reported that sensitization to food allergens and sensitization to airborne allergens had independent associations with increased fraction of exhaled nitric oxide (FeNO) and blood eosinophils in middle-aged adults and in young subjects with asthma. OBJECTIVE: To investigate the relation between IgE sensitization and several type 2 inflammation biomarkers in adult asthmatics. METHODS: FeNO, urinary eosinophil-derived neurotoxin (U-EDN), serum eosinophil cationic protein (S-ECP) and periostin were measured in 396 asthmatics, aged 17-76 years, from the Swedish GA2LEN study. Sensitization to airborne allergens was examined with skin prick tests (≥3 mm wheal) and sensitization to food allergens with measurement of specific IgE (≥0.35 kU/L). RESULTS: Asthmatics sensitized to food allergens had higher FeNO, 22.3 ppb (18.6, 26.7) vs 16.1 ppb (14.2, 18.2) (P = .005), S-ECP, 17.7 mg/L (14.8, 21.1) vs 12.8 mg/L (10.9, 14.9) (P = .01), and periostin, 73.7 (67.5, 80.3) ng/mL vs 59.9 (55.8, 64.2) ng/mL (P = .003), than non-sensitized subjects. Periostin levels in this group were also significantly higher than in the group sensitized only to airborne allergens (P = .01). Sensitization to food allergens related independently to FeNO (P = .02), S-ECP (P = .006) and periostin (P = .004), whereas sensitization only to airborne allergens related only to FeNO (P = .02) after adjustments for age, sex, height, weight and smoking history. FeNO correlated weakly with S-ECP (r = .17, P < .001), periostin (r = .19, P < .001) and U-EDN (0.16, P < .001). S-ECP also correlated weakly with U-EDN (r = .12, P = .02). None of the correlations between the remaining pairs of markers of type 2 inflammation were significant. CONCLUSIONS & CLINICAL RELEVANCE: Sensitization to food allergens related to several local and systemic type 2 inflammation markers, such as FeNO, S-ECP and periostin. Assessing the profile of allergic sensitization, including to food allergens, might improve the understanding and interpretation of inflammatory markers and potentially improve asthma management.

Patient-reported signs of dampness at home may be a risk factor for chronic rhinosinusitis: A cross-sectional study.

BACKGROUND: An association between dampness at home and respiratory conditions has been convincingly demonstrated in children. Fewer studies have been performed in adults, and data are lacking for chronic rhinosinusitis (CRS). With a prevalence of 10.9% in Europe, CRS imposes a significant burden on quality of life, as well as economy. OBJECTIVE: Our aim was to study CRS and other respiratory conditions in relation to dampness at home in a representative sample of adults. METHODS: The Swedish GA2 LEN questionnaire was answered by 26 577 adults (16-75 years) and included questions on respiratory symptoms, smoking, education and environmental exposure. CRS was defined according to the EP3 OS criteria. Dampness was defined as reporting water damage, floor dampness or visible moulds in the home during the last 12 months. The dampness score was ranked from 0 to 3, counting the number of signs of dampness reported. RESULTS: Dampness at home was reported by 11.3% and was independently related to respiratory conditions after adjustment for demographic and socio-economic factors and smoking: CRS odds ratio (OR) 1.71; allergic rhinitis OR 1.24; current asthma OR 1.21; wheeze OR 1.37; nocturnal dyspnoea OR 1.80; nocturnal coughing OR 1.34; and chronic bronchitis OR 1.64. The risk of CRS and most of the other respiratory conditions was further elevated in subjects reporting multiple signs of dampness. CONCLUSIONS AND CLINICAL RELEVANCE: This study demonstrated an independent association between dampness at home and CRS in adults. The high burden of this and the other respiratory conditions studied is a strong argument in favour of countering indoor dampness by improving building standards.

Serum periostin relates to type-2 inflammation and lung function in asthma: Data from the large population-based cohort Swedish GA(2)LEN.

BACKGROUND: Periostin has been suggested as a novel, phenotype-specific biomarker for asthma driven by type 2 inflammation. However, large studies examining relationships between circulating periostin and patient characteristics are lacking and the suitability of periostin as a biomarker in asthma remains unclear. AIM: To examine circulating periostin in healthy controls and subjects with asthma from the general population with different severity and treatment profiles, both with and without chronic rhinosinusitis (CRS), in relation to other biomarkers and clinical characteristics. METHODS: Serum periostin was examined by ELISA in 1100 subjects aged 17-76 from the Swedish Global Allergy and Asthma European Network (GA(2)LEN) study, which included 463 asthmatics with/without chronic rhinosinusitis (CRS), 98 individuals with CRS only, and 206 healthy controls. Clinical tests included measurement of lung function, Fraction of exhaled NO (FeNO), IgE, urinary eosinophil-derived neurotoxin (U-EDN), and serum eosinophil cationic protein (S-ECP), as well as completion of questionnaires regarding respiratory symptoms, medication, and quality of life. RESULTS: Although median periostin values showed no differences when comparing disease groups with healthy controls, multiple regression analyses revealed that periostin was positively associated with higher FeNO, U-EDN, and total IgE. In patients with asthma, an inverse relationship with lung function was also observed. Current smoking was associated with decreased periostin levels, whereas increased age and lower body mass index (BMI) related to higher periostin levels in subjects both with and without asthma. CONCLUSION: We confirm associations between periostin and markers of type 2 inflammation, as well as lung function, and identify novel constitutional factors of importance to the use of periostin as a phenotype-specific biomarker in asthma.

Important non-disease-related determinants of exhaled nitric oxide levels in mild asthma - results from the Swedish GA(2) LEN study.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) has a potential clinical role in asthma management. Constitutive factors such as age, height and gender, as well as individual characteristics, such as IgE sensitization and smoking, affect the levels of FeNO in population-based studies. However, their effect on FeNO in subjects with asthma has been scarcely studied. OBJECTIVE: To study the effects on FeNO of these commonly regarded determinants, as demonstrated in healthy subjects, as well as menarche age and parental smoking, in a population of asthmatics. MATERIAL AND METHODS: Fractional exhaled nitric oxide was measured in 557 subjects with asthma from the Swedish GA(2) LEN study. Allergic sensitization was assessed by skin prick tests to most common aeroallergens. Upper airway comorbidities, smoking habits, smoking exposure during childhood and hormonal status (for women) were questionnaire-assessed. RESULTS: Male gender (P < 0.001), greater height (P < 0.001) and sensitization to both perennial allergens and pollen (P < 0.001) are related to higher FeNO levels. Current smoking (P < 0.001) and having both parents smoking during childhood, vs. having neither (P < 0.001) or only one parent smoking (P = 0.002), are related to lower FeNO. Women with menarche between 9 and 11 years of age had lower FeNO than those with menarche between 12 and 14 years of age (P = 0.03) or 15 and 17 years of age (P = 0.003). CONCLUSIONS AND CLINICAL RELEVANCE: Interpreting FeNO levels in clinical practice is complex, and constitutional determinants, as well as smoking and IgE sensitisation, are of importance in asthmatic subjects and should be accounted for when interpreting FeNO levels. Furthermore, menarche age and parental smoking during childhood and their effects on lowering FeNO deserve further studies.

Health-related quality of life in children with objectively diagnosed staple food allergy assessed with a disease-specific questionnaire.

AIM: Among Swedish children of 0-12 years old, we investigated various food allergy-related exposures associated with health-related quality of life using a food allergy-specific questionnaire among children allergic to the staple foods cow's milk, hen's egg and/or wheat, and contextualised worse food allergy-associated health-related quality of life using a generic questionnaire versus controls. METHODS: In total, 85 children with objectively diagnosed allergy to the staple foods were included as cases, and 94 children matched for age and sex were included as controls. We administered a food allergy-specific parent-completed questionnaire originally developed by EuroPrevall to cases only, and a generic health-related quality of life questionnaire (EuroQol Health Questionnaire, 5 Dimensions; EQ 5-D); to both cases and controls. RESULTS: Hen's egg was the most common offending staple food, affecting 76% of cases. Approximately 7% of cases were allergic to all three staple foods. Parent-reported respiratory and cardiovascular symptoms were associated with worse health-related quality of life. Elements of disease severity [previous anaphylaxis (p < 0.001); epinephrine autoinjector prescription (p < 0.003)] were negatively associated with health-related quality of life. Cases had worse health-related quality of life measured by the EQ-5D compared to controls (p < 0.01). CONCLUSION: The use of a disease-specific questionnaire revealed that disease severity in children with objectively diagnosed allergy to the staple foods cow's milk, hen's egg and/or wheat is associated with worse health-related quality of life. The use of a generic questionnaire confirmed that cases have worse health-related quality of life than controls.

Socioeconomic evaluation of well-characterized allergy to staple foods in adults.

BACKGROUND: The aim of the present study was to evaluate if total, direct, indirect, and intangible costs differ between a cohort of adults with well-characterized allergy to staple foods ('cases') and controls. METHODS: Swedish adults with objectively diagnosed food allergy to cow's milk, hen's egg, and/or wheat were recruited at an outpatient allergy clinic. Controls age- and sex-matched to cases were recruited from the same geographic area. For assessing the household costs of food allergy, a disease-specific socioeconomic questionnaire, developed within EuroPrevall, was utilized. RESULTS: Overall annual total costs at the household level were significantly higher among adults with food allergy compared with controls (the difference amounted to 8164 €), whereas direct costs did not differ between cases and controls. However, household healthcare costs and costs for medicines were significantly higher for cases vs controls. Furthermore, indirect costs were significantly higher for households with food-allergic adults vs households without food-allergic adults. Specifically, more time was spent on performing domestic tasks due to a family member's food-allergy-related illness, as well as shopping and preparing food, and seeking food-allergy-related information. Presence of food allergy also affected intangible costs. Adults with food allergy experienced overall lower health status compared with controls. CONCLUSIONS: Swedish adults with allergy to staple foods have higher total costs determined as direct, indirect, and intangible costs using the disease-specific socioeconomic questionnaire. Thus, total costs were 8164 € higher per year in households with at least one adult allergic to staple foods compared with controls.

Staphylococcus aureus enterotoxin-specific IgE is associated with asthma in the general population: a GA(2)LEN study.

BACKGROUND: Specific IgE to Staphylococcus aureus enterotoxins (SE-IgE) has been associated with asthma. In the general population, we aimed to determine the prevalence of and risk factors for serum SE-IgE and to examine the association with asthma. METHODS: A postal questionnaire was sent to a random sample of adults in 19 centers across Europe. A random sample of respondents was invited for clinical examination upon which they answered a questionnaire, underwent skin prick tests (SPTs) for common aeroallergens, and provided blood for measurement of total IgE and SE-IgE. Risks were analyzed within centers using weighted logistic regression, and overall estimates calculated using fixed-effects meta-analysis. RESULTS: 2908 subjects were included in this analysis. Prevalence of positive SE-IgE was 29.3%; no significant geographic variation was observed. In contrast to positive skin prick tests, SE-IgE was more common in smokers (<15 pack-year: OR 1.11, P = 0.079, ≥15 pack-year: OR 1.70, P < 0.001), and prevalence did not decrease in older age-groups or in those with many siblings. Total IgE concentrations were higher in those with positive SE-IgE than in those with positive SPT. SE-IgE was associated with asthma (OR 2.10, 95% confidence interval [1.60-2.76], P = 0.001) in a concentration-dependent manner. This effect was independent of SPT result and homogeneous across all centers. CONCLUSIONS: We report for the first time that SE-IgE is common in the general population throughout Europe and that its risk factors differ from those of IgE against aeroallergens. This is the first study to show that SE-IgE is significantly and independently associated with asthma in the general population.

Chronic rhinosinusitis in asthma is a negative predictor of quality of life: results from the Swedish GA(2)LEN survey.

BACKGROUND: Asthma and chronic rhinosinusitis (CRS) both impair quality of life, but the quality-of-life impact of comorbid asthma and CRS is poorly known. The aim of this study was to evaluate the impact of CRS and other relevant factors on quality of life in asthmatic subjects. METHODS: This Swedish cohort (age 17-76 years) consists of 605 well-characterized asthmatics with and without CRS, 110 individuals with CRS only, and 226 controls and is part of the Global Allergy and Asthma European Network (GA(2) LEN) survey. The Mini Asthma Quality of Life Questionnaire (mAQLQ), the Euro Quality of Life (EQ-5D) health questionnaire, spirometry, skin prick test (SPT), exhaled nitric oxide (FeNO), smell test, and peak nasal inspiratory flow were used. RESULTS: Subjects having both asthma and CRS have lower mAQLQ scores in all domains (P < 0.001) and a lower EQ-5D index value and EQ-5D VAS value (P < 0.001) compared to those with asthma only. Asthmatics with CRS have significantly lower FEV1%pred and FVC%pred (88.4 [85.1-91.7] and 99.9 [96.7-103.0], respectively) compared with asthma only (91.9 [90.3-93.4] and 104.0 [102.5-105.5], respectively P < 0.05). Multiple regression analysis shows that low asthma quality of life is associated with having CRS (P < 0.0001), lower lung function (P = 0.008), current smoking (P = 0.01), BMI > 30 kg/m2 (P = 0.04), high age (P = 0.03), and a negative SPT (P = 0.04). CONCLUSIONS: Comorbid CRS was a significant and independent negative predictor of quality of life in asthmatics. Other negative factors were lower lung function, current smoking, obesity, advanced age, and having nonatopic asthma.

Asthma symptoms and nasal congestion as independent risk factors for insomnia in a general population: results from the GA(2)LEN survey.

BACKGROUND: Asthma and rhinitis have been related to insomnia. The aim of this study was to further analyse the association between asthma, nasal symptoms and insomnia and to identify risk factors for sleep disturbance among patients with asthma, in a large population-based set of material. METHOD: In 2008, a postal questionnaire was sent to a random sample of 45 000 adults in four Swedish cities. The questionnaire included questions on insomnia, asthma, rhinitis, weight, height, tobacco use and physical activity. RESULTS: Twenty-five thousand six hundred and ten subjects participated. Asthma was defined as either current medication for asthma or at least one attack of asthma during the last 12 months, and 1830 subjects (7.15%) were defined as asthmatics. The prevalence of insomnia symptoms was significantly higher among asthmatics than non-asthmatics (47.3% vs 37.2%, <0.0001). In the subgroup reporting both asthma and nasal congestion, 55.8% had insomnia symptoms compared with 35.3% in subjects without both asthma and nasal congestion. The risk of insomnia increased with the severity of asthma, and the adjusted OR for insomnia was 2.65 in asthmatics with three symptoms compared with asthmatics without symptoms. Nasal congestion (OR 1.50), obesity (OR 1.54) and smoking (OR 1.71) also increased the risk of insomnia. CONCLUSION: Insomnia remains a common problem among asthmatics. Uncontrolled asthma and nasal congestion are important, treatable risk factors for insomnia. Lifestyle factors, such as smoking and obesity, are also risk factors for insomnia among asthmatics.

Assessment of problematic severe asthma in children.

Assessment of problematic severe asthma in children should be performed in a step-wise manner to ensure an optimal approach. A four-step assessment scheme is proposed. First, a full diagnostic work-up is performed to exclude other diseases which mimic asthma. Secondly, a multi-disciplinary assessment is performed to identify issues that may need attention, including comorbidities. Thirdly, the pattern of inflammation is assessed, and finally steroid responsiveness is documented. Based upon these four steps an optimal individualised treatment plan is developed. In this article the many gaps in our current knowledge in all these steps are highlighted, and recommendations for current clinical practice and future research are made. The lack of good data and the heterogeneity of problematic severe asthma still limit our ability to optimise the management on an individual basis in this small, but challenging group of patients.

Endotoxin-induced shock in the pig--limited effects of low and high concentrations of inhaled nitric oxide.

AIM: This study was carried out to study the prophylactic effects of inhalation of nitric oxide (NO) before and during the induction of endotoxic shock. METHODS: Eighteen anaesthetized pigs received an infusion of 10-20 microg kg(-1) endotoxin during 2 h after pre-treatment with the cortisol-synthesis inhibitor metyrapone. Three groups were tested (n = 6 each) and received 0, 0.2 or 20 ppm inhaled NO from 30 min before start of endotoxin infusion until 4 h after start of endotoxin. Both 0.2 and 20 ppm NO were able to improve blood gas values. RESULTS: Area above curve values of arterial P2/FiO2 from 0 to 4 h were 0.83 +/- 0.09 kPa h (control), 0.78 +/- 0.22 (0.2 ppm NO, non-significant) and 0.31 +/- 0.06 (20 ppm NO, P < 0.01, Mann-Whitney U-test, compared to control). Area under curve values of PCO2 from 0 to 4 h were 3.96 +/- 0.66 kPa h (control), 1.20 +/- 0.46 (0.2 ppm NO, P < 0.05, Mann-Whitney U-test, compared to control) and 2.78 +/- 1.06 (20 ppm NO group, non-significant). The increase in pulmonary arterial pressure (PAP) was partly prevented by 20 ppm NO, but not by 0.2 ppm NO at 4 h. Inhaled NO did not affect the levels of BAL fluid total protein, tumour necrosis factor-alpha, interleukin-8 and neutrophil counts. CONCLUSIONS: The addition of a high (20 ppm), but not a low (0.2 ppm), concentration of NO to the inhaled air during endotoxin shock improves arterial oxygen tension and reduces pulmonary artery pressure. Neither dose affects lung mechanics or inflammatory indices, in spite of being given prophylactically.

Luminal nitric oxide and epithelial expression of inducible and endothelial nitric oxide synthase in collagenous and lymphocytic colitis.

BACKGROUND: Colonic nitric oxide (NO) production in collagenous colitis (CC) has been studied in a small number of patients and found increased. The cellular source of NO is believed to be the colonic epithelial cells. The aim of this study was to investigate colonic NO levels in patients with CC and lymphocytic colitis (LC), to compare with the histopathological status and with the clinical activity, and to assess the epithelial expression of inducible and endothelial nitric oxide synthase (iNOS and eNOS). METHODS: We included 19 patients with CC, 8 patients with LC and 15 controls. During colonoscopy, luminal gas was sampled and NO levels were measured using the chemiluminescence technique. Mucosal biopsies were obtained for routine histopathologic examination and immunohistochemical studies of iNOS and eNOS. Clinical activity, as measured by the mean frequency of daily bowel movements during the week prior to colonoscopy, was assessed. RESULTS: Luminal NO levels, median (25-75 percentiles), in the patients with CC and LC were greatly increased compared to the controls, 1673 (145-8143) parts per billion (ppb) and 1838 (1065-2694) ppb versus 28 (20-46) ppb (P < 0.005, both). A positive association was seen between NO levels and histopathological status as well as clinical activity. Strong expression of iNOS was seen in the surface epithelium in 5 of 6 patients with CC and in 2 of 5 patients with LC. CONCLUSIONS: The fact that luminal NO levels are related to histopathological status and correlate with clinical activity indicates that NO is involved in the pathophysiology of CC and LC. The epithelial cells are the most likely source of luminal NO.

Responses of the bronchial and pulmonary circulations to short-term nitric oxide inhalation before and after endotoxaemia in the pig.

The physiological responses of the bronchial circulation to acute lung injury and endotoxin shock are largely unexplored territory. This study was carried out to study the responsiveness of the bronchial circulation to nitric oxide (NO) inhalation before and after endotoxaemia, in comparison with the pulmonary circulation, as well as to study changes in bronchial blood flow during endotoxaemia. Six anaesthetized pigs (pre-treated with the cortisol-synthesis inhibitor metyrapone) received an infusion of 10 microg/kg endotoxin during 2 h. Absolute bronchial blood flow was measured via an ultrasonic flow probe around the bronchial artery. The pigs received increasing doses of inhaled NO over 5 min each (0, 0.2, 2 and 20 ppm) before and after 4 h of endotoxaemia. The increase in bronchial vascular conductance during 5 min of inhalation of 20 ppm NO before endotoxin shock was significantly higher (area under curve (AUC) 474.2 +/- 84.5% change) than after endotoxin shock (AUC 118.2 +/- 40.4%, P < 0.05 Mann-Whitney U-test). The reduction of the pulmonary arterial pressure by 20 ppm NO was not different. A short rebound effect of the pulmonary arterial pressure occurred after discontinuation of inhaled NO before endotoxaemia (AUC values above baseline 54.4 +/- 19.7% change), and was virtually abolished after endotoxaemia (AUC 6.1 +/- 4.0%, P = 0.052, Mann-Whitney U-test). Our results indicate that the responsiveness of the bronchial circulation to inhalation of increasing doses of inhaled NO during endotoxin shock clearly differ from the responsiveness of the pulmonary circulation. The reduced responsiveness of the bronchial circulation is probably related to decreased driving pressure for the bronchial blood flow. The absence of the short rebound effect on pulmonary arterial pressure (PAP) after induction of shock could be related to maximum constriction of the pulmonary vessels at 4 h.

Selective protective effects of nitric oxide inhalation on allergen-induced acute airway reactions in the pig.

BACKGROUND: Nitric oxide (NO) is thought to be an important mediator of inflammatory processes during allergic reactions in the respiratory tract. OBJECTIVE: This study was undertaken to investigate the effects of inhalation of NO on the allergen-induced acute airway reactions in the pig. METHODS: Specific pathogen-free pigs were sensitized with Ascaris suum antigen and challenged with an allergen aerosol during mechanical ventilation and anaesthesia. One group (n = 8) was treated with inhaled NO (20 ppm) which was given from 30 min before allergen challenge until the experiments were completed at 120 min after challenge. A control group (n = 8) did not receive NO (< 0.001 ppm). RESULTS: Inhalation of 20 ppm NO prevented the fall in arterial pO2/FiO2 levels that was observed in the control group (areas under the curve between 0 and 120 min were 3.7 +/- 1.4 kPa/min in NO-treated pigs vs. 15.9 +/- 3.4 in controls, P < 0.01, Mann-Whitney U-test) and it decreased baseline pulmonary arterial pressure (change from time-point - 30-0 was 3.1 +/- 5.3% in the control and - 19.9 +/- 3.5% in the NO group, P < 0.01), which in turn resulted in a lower pulmonary arterial pressure during allergen challenge. NO also caused vasodilatation in the bronchial circulation, resulting in increased bronchial vascular conductance throughout the experiment. NO inhalation caused a small, but non-significant, reduction in the allergen-induced bronchoconstrictor response, whereas histamine release, as detected in urine, was not changed. Total protein levels in bronchoalveolar lavage (BAL) fluid were significantly decreased in the NO group at 120 min after challenge compared with 45 min (373 +/- 101 microg/mL vs. 631 +/- 184, respectively, P < 0.05, Wilcoxon matched pairs test), whereas levels in the control group did not change between these two time-points (513 +/- 282 vs. 599 +/- 354, not significant). CONCLUSION: These findings indicate that NO inhalation improves ventilation/perfusion matching and causes some bronchodilatation during the allergen-induced acute airway reaction, whereas histamine release is not affected. Moreover, NO inhalation enhanced the clearance of extravasated protein in the airways, possibly through increased bronchial blood flow. Even though some protective effects were seen, this study does not support a therapeutic role for exogenous NO in acute allergic reactions.

Limitation of infarct size and attenuation of myeloperoxidase activity by an endothelin A receptor antagonist following ischaemia and reperfusion.

It has previously been shown that endothelin (ET) receptor antagonists limit myocardial ischaemia/reperfusion (I/R) injury. The mechanism behind this effect is still unclear. The aim of this study was to elucidate the possible relationship between cardioprotection by an ET(A) receptor antagonist and inhibition of neutrophil accumulation or activation in the myocardium determined as myeloperoxidase (MPO) activity during I/R. Anaesthetised pigs were subjected to 45 min ischaemia by ligation of the left anterior descending coronary artery (LAD) followed by 4 h of reperfusion. Infiltration of MPO-containing cells, presumably neutrophils, into the ischaemic area was confirmed with an immunohistochemical technique using antibodies against porcine MPO. Vehicle (n = 7) or the selective ET(A) receptor antagonist LU 135252 (LU; n = 7) were given into the LAD during the last 10 min of ischaemia and the first 5 min of reperfusion. There were no significant differences in LAD flow, mean arterial pressure, heart rate, or rate pressure product between the groups during I/R. The area at risk was similar in the two groups. LU reduced the final infarct size to 40+/-6% of the area at risk compared to 80+/-6% in the vehicle group (P < 0.001). Endothelin-like immunoreactivity increased 2-fold in the ischaemic area in the vehicle group (P < 0.01), but not in the group given LU. MPO activity was higher (2.5x) in the ischaemic than in the non-ischaemic myocardium of the vehicle group. The MPO activity in the ischaemic myocardium was significantly lower in the group given LU (7.0+/-1.2 units g(-1)) than in the vehicle group (14.2+/-1.9 units g(-1); P < 0.01). There was a significant correlation between the infarct size and MPO activity (P < 0.01, r = 0.68). In conclusion, local administration of the selective ET(A) receptor antagonist LU during the last period of ischaemia and early reperfusion reduces the extent of myocardial necrosis and MPO activity. This suggests that LU may exert its cardioprotective effect by inhibiting neutrophil-mediated injury.

Clozapine-induced Fos-protein expression in rat forebrain regions: differential effects of adrenalectomy and corticosterone supplement.

Unlike classical antipsychotic drugs, clozapine activates the hypothalamo-pituitary-adrenal axis and induces a specific regional pattern of Fos-protein expression in the rat forebrain. Whether corticosterone plays a role in the clozapine-induced Fos response is the subject of this study. Some rats were adrenalectomized and in a number, including intact animals, a corticosterone pellet (100 mg s.c.) was implanted; after 1 week, a single dose of clozapine (20 mg kg(-1) i.p.) was administered. The clozapine-induced Fos response was not affected by adrenalectomy, apart from the nucleus accumbens shell, the subfornical organ and the supraoptic nucleus; there was an increased response in the nucleus accumbens shell, while other regions showed less Fos immunoreactivity. Implantation of the corticosterone pellet in both sham-operated and adrenalectomized animals, reduced the clozapine-induced Fos responses strongly in the hypothalamic paraventricular nucleus, the subfornical organ and possibly in the prefrontal cortex; in the supraoptic nucleus, this effect was seen only in intact animals. The effect of clozapine on plasma corticosterone levels was also diminished by supplemental corticosterone treatment. These results imply that the effects of clozapine are partially dependent upon hypothalamo-pituitary-adrenal axis integrity and activation. The efficacy of clozapine in the treatment of polydipsia and hyponatremia in chronic psychiatric patients may involve clozapine-mediated activation of the cellular activity in the subfornical organ.

Synergistic septicemic action of the gram-positive bacterial cell wall components peptidoglycan and lipoteichoic acid in the pig in vivo.

Despite the fact that gram-positive infections constitute around 50% of all cases leading to septic shock, little is yet known about the mechanisms involved. This study was carried out to find out more about the effects of cell wall components peptidoglycan (PepG) and lipoteichoic acid (LTA) of the gram-positive bacterium Streptococcus pyogenes in the pig. Specific pathogen-free pigs (20 kg bodyweight) were pretreated with metyrapone (a cortisol-synthesis inhibitor) and then were given 2-h infusions of 160 microg/kg of PepG (n = 5), 160 microg/kg LTA (n=5), or a combination of both (LTA + PepG, 160 microg/kg each, n = 5). Four hours after start of the infusions, the PepG, LTA, and LTA + PepG groups showed decreases in mean arterial pressure (change of -11%, -25%, and -47% from baseline, respectively), dynamic lung compliance (-18%, -24%, and -38%), arterial oxygen tension (-10%, -16%, and -37%), changes in blood leukocyte numbers (+11%, -27%, and -67%), and increases in pulmonary vascular resistance index (+7%, +106%, and +307% from baseline) and metabolic acidosis (base excess values decreased with 1.8, 2.3 and 8.1 units). The differences between the PepG and LTA + PepG groups were statistically significant (P < 0.05, Kruskal-Wallis tests), but not between LTA and LTA + PepG groups. However, no changes in systemic nitric oxide (NO) production could be detected, which is much in contrast to studies on lower order animals. Moreover, comparison of the results obtained using this model with those obtained in a model of endotoxin-induced septic shock showed distinct difference in the mechanisms by which gram-positive and gram-negative bacterial components exert their actions. For example, a marked fall in systemic blood pressure and dynamic lung compliance is seen in both models, but in the present gram-positive sepsis model, much less interleukin-8 and tumor necrosis factor-alpha are produced. In conclusion, this study showed that PepG and LTA act synergistically to cause respiratory failure and septic shock in the pig. The infusion of the combination of PepG and LTA in the pig could serve as a new, well-controlled model for studies of gram-positive sepsis.

Nitric oxide synthase inhibition augments acute allergic reactions in the pig airways in vivo.

The aim of this study was to examine the effects of nitric oxide synthase inhibition on antigen- and histamine-induced acute airway reactions, in order to clarify the possible modulating role of NO. Twelve specific-pathogen-free pigs (sensitized with Ascaris suum antigen) were challenged with an antigen aerosol during mechanical ventilation and anaesthesia. Six pigs were pretreated with N(G)-nitro-L-arginine (L-NA, 10 mg x kg(-1)), a NO synthase inhibitor, 30 min before challenge. In separate experiments, seven sensitized pigs received histamine (5 mg) aerosols before and after L-NA treatment. It was found that pretreatment with L-NA resulted in an enhanced airways resistance response to antigen (areas under the curve 0-90 min were (mean+/-SEM) 1,119+/-160 versus 555+/-56 (cmH2O x L(-1) x s(-1) x min for controls, p<0.05 (Mann-Whitney U-test), whereas this response to histamine was not affected by L-NA. Moreover, L-NA pretreatment significantly enhanced total protein (1.85+/-0.43 versus 0.31+/-0.06 g x L(-1), p<0.01) and histamine levels (42.8+/-16.0 versus 2.6+/-0.8 nM, p<0.05) in bronchoalveolar lavage fluid 45 min after antigen challenge. In conclusion, this study showed that N(G)-nitro-L-arginine enhanced reactions occurring during the acute allergic reaction in pigs in vivo. This indicates a protective role of nitric oxide, which might occur through downregulation of histamine release from mast cells rather than a direct bronchodilating effect of nitric oxide.

Effect of cortisol-synthesis inhibition on endotoxin-induced porcine acute lung injury, shock, and nitric oxide production.

In the process of developing a model of Escherichia coli endotoxin-induced acute lung injury and shock in specific pathogen-free pigs, the effects of pretreatment with metyrapone (a cortisol-synthesis inhibitor) were examined. Metyrapone was administered 1.5 h before start of endotoxin infusion at t = 0 h (MET-ETOX group, n = 6). At the end of the experiments (t = 4 h) a bronchoalveolar lavage (BAL) was performed. Control animals received only endotoxin (CON-ETOX group, n = 6) or metyrapone (MET-CON group, n = 4). The following results are presented as means +/- SEM. It was found that metyrapone successfully blocked endogenous cortisol synthesis (plasma cortisol levels were 41.0 +/- 5.9 nM in MET-ETOX vs. 339.0 +/- 37.7 nM in CON-ETOX at t = 4 h, P <0.01). At t = 4 h the MET-ETOX animals had substantially increased systemic hypotension compared to the CON-ETOX group (mean arterial pressure 26.7 +/- 4.3 vs. 77.7 +/- 12.2 mmHg, P <0.01), decreased dynamic lung compliance (10.9 +/- 0.7 vs. 13.7 +/- 0.6 ml/cmH2O, P <0.01), increased percentage of BAL neutrophils (28.4 +/- 6.5 vs. 6.6 +/-1.8, P <0.01), pulmonary edema (BAL total protein 0.82 +/- 0.21 vs. 0.42 +/- 0.09 mg/mL, P <0.05), elevated levels of interleukin-8 (1924 +/- 275 vs. 324 +/- 131 pg/mL, P <0.01) and acidosis (pH 7.11 +/- 0.03 vs. 7.23 +/- 0.06, P <0.05). The MET-ETOX group also showed an increased pulmonary hypertension between 2 and 3 h after start of endotoxin infusion and a trend toward significantly increased levels of plasma interleukin-8 (P = 0.052). Arterial pCO2, pO2/FiO2, plasma endothelin-1, plasma TNFalpha, and blood leukocytes were not markedly influenced by the plasma cortisol levels. Nitric oxide production did not seem to be altered by endotoxin infusion in this model, in contrast to other animal studies; this discrepancy could be thought to be due to endotoxin-dosage differences or species differences. It is concluded that if endogenous cortisol production is blocked by metyrapone, the reactions occurring as a result of the endotoxin-induced acute lung injury and shock are greatly enhanced and that therefore pretreatment with metyrapone might be an important addition to this model with specific pathogen-free pigs.