Francesca Fumagalli

Cysteinyl-leukotrienes receptor activation in brain inflammatory reactions and cerebral edema formation: a role for transcellular biosynthesis of cysteinyl-leukotrienes

We studied the effect of intravascular activation of human neutrophils on the synthesis of cysteinyl leukotrienes (cysLT) and the formation of cerebral edema in guinea‐pig brains. Challenge with the chemotactic formylated tripeptide fMLP (0.1 µM) of neutrophil‐perfused brain in vitro resulted in blood‐brain barrier disruption associated with a significant increase of cysLT. Both events were completely prevented by neutrophil pretreatment with a specific 5‐lipoxygenase (5‐LO) inhibitor. Perfusion with the 5‐LO metabolite leukotriene B4 (10 nM), together with neutrophils treated with the 5‐LO inhibitor, did not restore the alteration in permeability observed upon perfusion with untreated and activated neutrophils. The dual cysLT1‐cysLT2 receptor antagonist BAYu9773 was more potent and more effective than a selective cysLT1 antagonist in preventing the brain permeability alteration induced by neutrophil activation. RT‐PCR showed significant expression of cysLT2 receptor mRNA in human umbilical vein endothelial cells. Intravital microscopy in mice showed that inhibition of leukotriene synthesis significantly reduced firm adhesion of neutrophils to cerebral vessels without affecting rolling. These data support the hypothesis that neutrophil and endothelial cells cooperate toward the local synthesis of cysLT within the brain vasculature and, acting via the cysLT2 receptor on endothelial cells, may represent a contributing pathogenic mechanism in the development of cerebral inflammation and edema.

Amplitude spectrum area to guide resuscitation—A retrospective analysis during out-of-hospital cardiopulmonary resuscitation in 609 patients with ventricular fibrillation cardiac arrest☆

INTRODUCTION The capability of amplitude spectrum area (AMSA) to predict the success of defibrillation (DF) was retrospectively evaluated in a large database of out-of-hospital cardiac arrests. METHODS Electrocardiographic data, including 1260 DFs, were obtained from 609 cardiac arrest patients due to ventricular fibrillation. AMSA sensitivity, specificity, accuracy, and positive and negative predictive values (PPV, NPV) for predicting DF success were calculated, together with receiver operating characteristic (ROC) curves. Successful DF was defined as the presence of spontaneous rhythm ≥40bpm starting within 60s from the DF. In 303 patients with chest compression (CC) depth data collected with an accelerometer, changes in AMSA were analyzed in relationship to CC depth. RESULTS AMSA was significantly higher prior to a successful DF than prior to an unsuccessful DF (15.6±0.6 vs. 7.97±0.2mV-Hz, p<0.0001). Intersection of sensitivity, specificity and accuracy curves identified a threshold AMSA of 10mV-Hz to predict DF success with a balanced sensitivity, specificity and accuracy of almost 80%. Higher AMSA thresholds were associated with further increases in accuracy, specificity and PPV. AMSA of 17mV-Hz predicted DF success in two third of instances (PPV of 67%). Low AMSA, instead, predicted unsuccessful DFs with high sensitivity and NPV >97%. Area under the ROC curve was 0.84. CC depth affected AMSA value. When depth was <1.75in., AMSA decreased for consecutive DFs, while it increased when the depth was >1.75in. (p<0.05). CONCLUSIONS AMSA could be a useful tool to guide CPR interventions and predict the optimal timing of DF.

Amplitude Spectrum Area to Guide Defibrillation A Validation on 1617 Patients With Ventricular Fibrillation

Background— This study sought to validate the ability of amplitude spectrum area (AMSA) to predict defibrillation success and long-term survival in a large population of out-of-hospital cardiac arrests. Methods and Results— ECGs recorded by automated external defibrillators from different manufacturers were obtained from patients with cardiac arrests occurring in 8 city areas. A database, including 2447 defibrillations from 1050 patients, was used as the derivation group, and an additional database, including 1381 defibrillations from 567 patients, served as validation. A 2-second ECG window before defibrillation was analyzed, and AMSA was calculated. Univariable and multivariable regression analyses and area under the receiver operating characteristic curve were used for associations between AMSA and study end points: defibrillation success, sustained return of spontaneous circulation, and long-term survival. Among the 2447 defibrillations of the derivation database, 26.2% were successful. AMSA was significantly higher before a successful defibrillation than a failing one (13±5 versus 6.8±3.5 mV-Hz) and was an independent predictor of defibrillation success (odds ratio, 1.33; 95% confidence interval, 1.20–1.37) and sustained return of spontaneous circulation (odds ratio, 1.22; 95% confidence interval, 1.17–1.26). Area under the receiver operating characteristic curve for defibrillation success prediction was 0.86 (95% confidence interval, 0.85–0.88). AMSA was also significantly associated with long-term survival. The following AMSA thresholds were identified: 15.5 mV-Hz for defibrillation success and 6.5 mV-Hz for defibrillation failure. In the validation database, AMSA ≥15.5 mV-Hz had a positive predictive value of 84%, whereas AMSA ⩽6.5 mV-Hz had a negative predictive value of 98%. Conclusions— In this large derivation-validation study, AMSA was validated as an accurate predictor of defibrillation success. AMSA also appeared as a predictor of long-term survival.Background— This study sought to validate the ability of amplitude spectrum area (AMSA) to predict defibrillation success and long-term survival in a large population of out-of-hospital cardiac arrests. Methods and Results— ECGs recorded by automated external defibrillators from different manufacturers were obtained from patients with cardiac arrests occurring in 8 city areas. A database, including 2447 defibrillations from 1050 patients, was used as the derivation group, and an additional database, including 1381 defibrillations from 567 patients, served as validation. A 2-second ECG window before defibrillation was analyzed, and AMSA was calculated. Univariable and multivariable regression analyses and area under the receiver operating characteristic curve were used for associations between AMSA and study end points: defibrillation success, sustained return of spontaneous circulation, and long-term survival. Among the 2447 defibrillations of the derivation database, 26.2% were successful. AMSA was significantly higher before a successful defibrillation than a failing one (13±5 versus 6.8±3.5 mV-Hz) and was an independent predictor of defibrillation success (odds ratio, 1.33; 95% confidence interval, 1.20–1.37) and sustained return of spontaneous circulation (odds ratio, 1.22; 95% confidence interval, 1.17–1.26). Area under the receiver operating characteristic curve for defibrillation success prediction was 0.86 (95% confidence interval, 0.85–0.88). AMSA was also significantly associated with long-term survival. The following AMSA thresholds were identified: 15.5 mV-Hz for defibrillation success and 6.5 mV-Hz for defibrillation failure. In the validation database, AMSA ≥15.5 mV-Hz had a positive predictive value of 84%, whereas AMSA ≤6.5 mV-Hz had a negative predictive value of 98%. Conclusions— In this large derivation-validation study, AMSA was validated as an accurate predictor of defibrillation success. AMSA also appeared as a predictor of long-term survival. # CLINICAL PERSPECTIVE {#article-title-40}

Postresuscitation treatment with argon improves early neurological recovery in a porcine model of cardiac arrest.

Introduction Effects of postresuscitation treatment with argon on neurologic recovery were investigated in a porcine model of cardiac arrest (CA) with an underlying acute myocardial infarction. Methods The left anterior descending coronary artery was occluded in 12 pigs, and CA was induced. After 8 min of untreated CA, cardiopulmonary resuscitation was performed for 5 min before defibrillation. Following resuscitation, animals were subjected to 4-h ventilation with 70% argon/30% oxygen or 70% nitrogen/30% oxygen. Myocardial function was echocardiographically assessed, and serum neuron-specific enolase was measured. Animals were observed up to 72 h for assessment of survival and neurologic recovery. Results All the animals were resuscitated and survived for 72 h, except for a control pig. Ventilation with argon did not have any detrimental effects on hemodynamics and respiratory gas exchange. All the six argon-treated animals had a fast and complete 72-h neurologic recovery, in contrast to only two of the six controls (P < 0.05). Seventy-two-hour neurologic alertness score and neurologic deficit score were, respectively, 100 and 0 in the argon group and 79 and 29 in the control one (P < 0.01 and P < 0.05). Significantly lower increases in serum neuron-specific enolase (12% vs. 234%) and minimal histological brain injury (neuronal degeneration: 0 vs. 1) were also observed in argon-treated animals, in comparison to controls. Conclusions In this model, postresuscitation treatment with argon allowed for a faster and complete neurologic recovery, without detrimental effects on hemodynamics and respiratory gas exchanges.

Hydroxytyrosol attenuates peripheral neuropathy in streptozotocin-induced diabetes in rats

Peripheral neuropathy is one of the most frequent and severe complications of diabetes. Hydroxytyrosol (HT), the major antioxidant polyphenolic compound of olive oil, has been investigated as a new potential treatment to counteract the progression of peripheral diabetic neuropathy in rats. An established model of streptozotocin-induced diabetes has been used. After confirmation of hyperglycemia, diabetic and nondiabetic animals were randomized to receive either a low dose or a high dose of HT, or the corresponding vehicle, for 6 weeks. At the end of the 6-week period of treatment, HT blunted plasma thiobarbituric acid-reactive substances increase (p < 0.05) and significantly reduced nerve conduction velocity (p < 0.05) and thermal nociception impairment in diabetic rats (p < 0.05). Sciatic nerve Na(+), K(+)-ATPase activity reduction was also abolished by HT (p < 0.05). The present study provides evidence of the therapeutic potential of the natural substance hydroxytyrosol in the early stage of diabetic neuropathy.

Bronchodilators Modulate Inflammation In Chronic Obstructive Pulmonary Disease Subjects

Chronic obstructive pulmonary disease (COPD) is characterized by neutrophilic airway inflammation and oxidative stress. Leukotriene B₄ (LTB₄), a potent proinflammatory mediator, is synthesized by 5-lipoxygenase (5-LO), which is activated by the presence of lipid hydroperoxides resulting from oxidative stress on biological membranes. We proposed to evaluate the effect of a four week treatment with two different bronchodilators of common practice in COPD treatment, on the production of reactive oxygen species (ROS), in particular superoxide anions, and of LTB₄ by peripheral blood neutrophils obtained from COPD subjects. 24 subjects among the COPD outpatients were enrolled, and randomized to receive either formoterol (12 μg bid) or tiotropium (18 μg od). Peripheral blood neutrophils were obtained at the start and at the end of the treatment, and production of superoxide anions and of LTB₄ were evaluated as previously published. The results obtained showed a decrease in the unstimulated production of superoxide by isolated neutrophils in both groups, but tiotropium only was effective in modulating the production of LTB₄, while formoterol caused an increased production of superoxide in response to fMLP, when compared to values obtained before treatment. In conclusion, tiotropium showed a better antiinflammatory activity profile when compared to formoterol in a clinical setting, reducing superoxide and LTB₄ production by peripheral neutrophils obtained from COPD subjects.

The Potential Role of Tocopherol in Asthma and Allergies Modification of the Leukotriene Pathway

Metabolism of arachidonic acid via the 5-lipoxygenase (5-LO) pathway leads to the formation of hydroperoxyeicosatetraenoic acids (HPETEs) and leukotriene (LT) A4. This unstable allylic epoxide can be further converted by secondary enzymes into LTB4 and cysteinyl LTs. LTs represent a family of potent biologically active compounds synthesised by specific cell types and by transcellular biosynthetic mechanisms. Cysteinyl LTs are involved in the pathogenesis of asthma, and recent data indicate that individuals with asthma may have enhanced basal excretion of urinary LTE4 compared with normal individuals.Tocopherol (vitamin E) and tocopherol acetate strongly inhibit potato 5-LO in an irreversible and noncompetitive way, and, by affecting the redox state of cells possessing 5-LO, they may influence the production of biologically active LTs. It has been reported that normal plasma levels of tocopherol may enhance the lipoxygenation of arachidonic acid, whereas higher tocopherol levels exert a suppressive effect that is consistent with its role as a hydroperoxide scavenger.Receptor-mediated activation of neutrophils in individuals with asthma results in the synthesis of LTs. This activation is inhibited by tocopherol in a concentration-dependent manner. Additional controlled studies are needed to assess the effect of tocopherol on leukotriene production in asthmatic individuals. The results of these studies may be useful in developing new therapeutic approaches in asthmatic/allergic patients.

A new class of nitric oxide-releasing derivatives of cetirizine; pharmacological profile in vascular and airway smooth muscle preparations

The pharmacological properties of compounds NCX 1512 and NCX 1514, synthesized by linking the histamine H1‐receptor antagonist cetirizine to NO‐releasing spacer groups, are reported. The aim was to establish if the compounds retained the antihistamine action of the parent compound, to assess their efficacy as NO donors and to test if they had broader antiallergic activity than cetirizine in the lung.

Early kynurenine pathway activation following cardiac arrest in rats, pigs, and humans

AIM OF THE STUDY Kynurenine pathway (KP) is a major route of the tryptophan (TRP) catabolism. In the present study, TRP and KP metabolites concentrations were measured in plasma from rats, pigs and humans after cardiac arrest (CA) in order to assess KP activation and its potential role in post-resuscitation outcome. METHODS Plasma was obtained from: (A) 24 rats, subjected to 6 min CA and 6 min of cardiopulmonary resuscitation (CPR); (B) 10 pigs, subjected to 10 min CA and 5 min CPR; and (C) 3 healthy human volunteers and 5 patients resuscitated from CA. KP metabolites were quantified by liquid chromatography multiple reaction monitoring mass spectrometry. Assessments were available at baseline, and 1-4h, and 3-5 days post-CA. RESULTS KP was activated after CA in rats, pigs, and humans. Decreases in TRP occurred during the post-resuscitation period and were accompanied by significant increases in its major metabolites, 3-hydroxyanthranilic acid (3-HAA) and kynurenic acid in each species, that persisted up to 3-5 days post-CA (p<0.01). In rats, changes in KP metabolites reflected changes in post-resuscitation myocardial function. In pigs, changes in TRP and increases in 3-HAA were significanlty related to the severity of cerebral histopathogical injuries. In humans, KP activation was observed, together with systemic inflammation. Post-CA increases in 3-HAA were greater in patients that did not survive. CONCLUSION In this fully translational investigation, the KP was activated early following resuscitation from CA in rats, pigs, and humans, and might have contributed to post-resuscitation outcome.

Specific disgust processing in the left insula: New evidence from direct electrical stimulation

Neuropsychological and neuroimaging studies yielded controversial results concerning the specific role of the insula in recognizing the facial expression of disgust. To verify whether the insula has a selective role in facial disgust processing, emotion recognition was studied in thirteen patients during intraoperative stimulation of the insula in awake surgery performed for removal of a glioma close to this structure. Direct electrical stimulation of the left insula produced a general decrease in emotion recognition but only in the case of disgust there was a statistically significant detrimental effect (p=0.004). Happiness and anger were the best and the worst recognized emotion, respectively. The worst baseline performance with anger and, partly, fear could be explained with the involvement of the left temporal regions, striatum, and the connection between the striatum and the frontal lobe, as suggested in previous studies. Therefore, upon these intra-operative evidences, we argue for a selective role of the left insula in disgust recognition, although a (non significant) decrease in the recognition of other negative emotions was found. However, additional networks can develop, as demonstrated by the fact that disgust recognition was not impaired after surgery even in patients with insular resection in the current as in previous studies.