Development of Tunable Ferroelectric Ceramic Capacitors

Ferroelectric perovskite ceramics with a high dielectric constant, low loss, high tunability, and high electric breakdown are ideal for Nonlinear Transmission Lines (NLTLs) to generate radio frequency (RF) signals at high-power levels. To achieve the required properties, a comprehensive study of the material phase transitions and the optimal ratio adjustment between the chemical elements in the perovskite crystal structure are required. The advancement of this solid-state technology is the most promising optimization for NLTLs in developing high-power (>100 MW) devices with high tunability (>60%) and high repetition rate (>1 kHz) for soliton generation. The barium strontium zirconium titanate (BSZT) ceramic compositions were synthesized and characterized to maximize material tunability. The composition Ba_0.97Sr_0.03Zr_0.2Ti_0.8O₃ exhibited a high permittivity (>12,200), low loss tangent (<0.01), and an exceptional tunability of the order of 79% at an electric field of 10 kV/mm near the phase temperature transition at 300 K. Ferroelectric ceramic is an outstanding material with promising characteristics for producing RF signals in an NLTL, and here, the BSZT is considered for this application.

Moderate to severe atopic dermatitis in adolescents treated with dupilumab: a multicenter Italian real-world experience

Background

Moderate‐to‐severe atopic dermatitis (AD) in the adolescence is a high burden disease, and its treatment can be very challenging due to paucity of approved systemic drugs for this age and their side‐effects. Dupilumab was recently approved for treatment of adolescent AD.

Objectives

A multicentre, prospective, real‐world study on the effectiveness and safety of dupilumab in adolescents (aged from ≥12 to <18 years) with moderate‐to‐severe AD was conducted. The main AD clinical phenotypes were also examined.

Methods

Data of adolescents with moderate‐to‐severe AD treated with dupilumab at label dosage for 16 weeks were collected. Treatment outcome was assessed by EASI, NRS itch, NRS sleep loss and CDLQI scores at baseline and after 16 weeks of treatment. The clinical scores were also evaluated according to clinical phenotypes.

Results

One hundred and thirty‐nine adolescents were enrolled in the study. Flexural eczema and head and neck eczema were the most frequent clinical phenotypes, followed by hand eczema and portrait‐like dermatitis. Coexistence of more than 1 phenotype was documented in 126/139 (88.5%) adolescents. Three patients (2.1%) contracted asymptomatic SARS‐CoV‐2 infection and 1 of the discontinued dupilumab treatment before the target treatment period. A significant improvement in EASI, NRS itch, NRS sleep loss and CDLQI was observed after 16 weeks of treatment with dupilumab. This outcome was better than that observed in clinical trials. Dupilumab resulted effective in all AD phenotypes, especially in diffuse eczema. Twenty‐eight (20.1%) patients reported adverse events, conjunctivitis and flushing being the most frequent. None of patients discontinued dupilumab due to adverse event.

Conclusions

Dupilumab in adolescent AD showed excellent effectiveness at week 16 with consistent improvement of all clinical scores. Moreover, dupilumab showed a good safety profile also in this COVID‐19 pandemic era.

Abnormal gut motility in inflammatory bowel disease: an update

BACKGROUND

There is substantial evidence linking disturbed gastrointestinal motility to inflammation. Thus, it is not surprising that abnormalities of gastrointestinal motility play a role in inflammatory bowel disease (IBD), affecting patient outcomes. We performed a review of the literature to investigate the relationship between abnormal gut motility and IBD.

METHODS

With an extensive literature search, we retrieved the pertinent articles linking disturbed gut motility to IBD in various anatomical districts.

RESULTS

The evidence in the literature suggests that abnormal gastrointestinal motility plays a role in the clinical setting of IBD and may confuse the clinical picture.

CONCLUSIONS

Abnormal gut motility may be important in the clinical setting of IBD. However, additional data obtained with modern techniques (e.g., magnetic resonance imaging) are needed to individuate in a more precise manner gastrointestinal motor dysfunctions, to understand the nature of clinical manifestations and properly tailor the treatment of patients.

A long-term follow-up in conservative management of unilateral ureteropelvic junction obstruction with poor drainage and good renal function

The aim of the study was to retrospectively review the outcome of neonatal ureteropelvic junction obstruction with a good renal function and a poor drainage at a first diuretic renal scan, in cases where surgery was recommended on the basis of a loss of renal function, worsening of hydronephrosis or occurrence of clinical symptoms. Hydronephrosis was graded from 1 to 4 or as ureteral tract dilatation (UTD) P1 to UTD P3. During follow-up, 15 out of 38 patients (34.2%) required surgery while 25 out of 38 (65.8%) could have been managed conservatively. In patients with grade 2, 3, and 4 hydronephrosis, the ureteropelvic junction obstruction resolved or improved spontaneously in 100%, 63%, and 33% of cases (in 100% of UTD P1, 67% of UTD P2, and 50% of UTD P3), respectively. The median of follow-up was 14 years. Chi-square test showed a significant relationship between initial grade of hydronephrosis or UTD and the possibility of an efficient conservative management (p = 0.0088 and p = 0.0460).Conclusion: Conservative management can be safely achieved in ureteropelvic junction obstruction with poor drainage. Scheduled controls are needed for early discovery of functional renal deterioration. High-grade hydronephrosis is unlikely to resolve spontaneously and is often accompanied by a loss of renal function during the first years of life. What is Known: • There is controversy about which management should be adopted in infants with unilateral ureteropelvic junction obstruction with poor drainage but good differential renal function. What is New: • Long-term follow-up suggests that conservative management can be safely achieved also in unilateral ureteropelvic junction obstruction with poor drainage in more than 60% of cases, even if high-grade hydronephrosis is unlikely to resolve spontaneously and it is often accompanied by a loss of renal function during the first years of life. In our experience, surgical intervention was required in more than 50% of cases before 1 year of life and in all cases before 3 years of life.

Celiac disease, non-celiac gluten sensitivity and inflammatory bowel disease

Celiac disease (CD) and inflammatory bowel disease (IBD), such as Crohn's disease (CrD) and ulcerative colitis (UC), are chronic inflammatory condition of the gastro-intestinal tract. The prevalence of IBD in celiac patients has been reported as 5-10 times higher than in the general population. The possibility of the presence of CD in IBD should be considered in IBD patients with long-term iron deficiency anemia (IDA) not responsive to iron supplementation. Non-celiac gluten sensitivity (NCGS) is characterized by intestinal and extra intestinal symptoms due to the ingestion of gluten-containing food in subject without CD and/or wheat allergy. Patients with Crohn's disease and SR-NCGS were more significantly affected by joint pains compared to UC patients (50% versus 11.1%). In Crohn's patients, a higher percentage of fatigue (50% versus 38.9%) and headache (27.3% versus 22.2%) was evident. For the association between NCGS and IBD new studies are warranted and, at this moment, a gluten free diet (GFD) may be useful more in CrD than in UC.

Enteric nervous system abnormalities in inflammatory bowel diseases

Various studies have described abnormalities of the enteric nervous system (ENS) in tissue samples from patients with chronic idiopathic inflammatory bowel diseases (IBD). The distribution of density of the different cell types of the ENS was however not studied in a systematic way. The aim of this study was to examine the density of neurons, enteroglial cells and interstitial cells of Cajal (ICC) in the different plexuses of the ENS in samples from patients with Crohn's disease (CD), ulcerative colitis (UC) and controls. Tissue samples from 16 patients with CD (ileum) and 16 patients with UC obtained in involved and non-involved areas were studied using immunohistochemistry with antibodies directed against neuron-specific enolase, S100, C-Kit and CD3. Sections were analysed blindly by two pathologists and the number of positive cells was counted for each type. Overall, an increase was noted for neuronal cell bodies, enteroglia and ICC in the deep muscular plexus in CD. In uninvolved areas of CD patients, the number of enteroglial cells was decreased. In UC, an increase of ICC in the muscularis propria and enteroglial cells was observed in diseased tissue. The study confirms the presence of abnormalities of the different cells of the ENS in IBD. The presence of lesions in samples from uninvolved areas, such as a reduction of enteroglia, supports a pathogenetic role of the ENS.

A simplified method for anal ultrasonography: assessment of patient satisfaction and the simplicity of the procedure

BACKGROUND

Anal endosonography reliably visualizes and identifies anal sphincter abnormalities. However, dedicated probes are quite expensive. We evaluated a simple and less-costly procedure for anal endosonography involving the insertion of the endoscope through a disposable anoscope filled with standard ultrasound gel in terms of patient satisfaction and the simplicity of the procedure in comparison with the standard technique in a unit that already had echoendoscopes available.

METHODS

The two techniques were used in 35 subjects without anal abnormalities and data on the simplicity of the procedures, patient discomfort, the quality of images, and the time needed to perform the procedures were compared.

RESULTS

All the variables under investigation scored significantly better with the modified technique compared to the standard one. No differences in thickness of either the internal or the external anal sphincter were found between the two methods.

CONCLUSIONS

This simple and less-costly adaptation of anal ultrasonography allows good quality examinations to be performed with better patient comfort in units with echoendoscopes already available, avoiding the need for a more expensive dedicated probe.

Inter- and intraobserver variability in sonographic measurement of the lower uterine segment after a previous Cesarean section

OBJECTIVE

To evaluate the reproducibility of sonographic measurement of the lower uterine segment in pregnant women at term.

METHODS

Two independent observers performed transabdominal sonography on 129 women between 36 and 38 weeks of gestation who had had a previous Cesarean section. Sonography was performed when the patients had a full and a half-full bladder; in 100 patients, the measurements were also performed transvaginally, with the patients having an empty bladder. Agreement was quantified by the intraclass correlation coefficient and, using a cut-off of 3.5 mm, by the kappa coefficient.

RESULTS

The intraobserver agreement was generally high (intraclass correlation coefficient > 0.90). The interobserver agreement was higher on transvaginal (intraclass correlation coefficient, 0.94) compared with transabdominal (0.70 and 0.84, with full and half-full bladder, respectively) ultrasound. The kappa coefficient was 0.75 transvaginally, compared with 0.34 and 0.54 using the transabdominal approach, with full and half-full bladder, respectively.

CONCLUSION

The agreement between two observers for sonographic transvaginal measurement of the lower uterine segment can be considered good, compared with poor to moderate agreement using the transabdominal approach.

The giant umbilical cord

The giant umbilical cord is a rare malformation of the umbilical cord that can easily be diagnosed on prenatal scans and is unmistakable postnatally. We report a case to highlight issues of this rare finding. Visual diagnosis is easy and surgical repair is usually required.

D-dimer levels during delivery and the postpartum

BACKGROUND

D-dimer (DD) measurement has proved to be very useful to exclude venous thromboembolism (VTE) in outpatients. However, during pregnancy, the progressive increase as well as the interindividual variations of DD means that in this instance they are of poor value to rule out VTE. Only a few studies have reported measurements of DD levels in the postpartum.

OBJECTIVES

To measure DD sequentially in the puerperium in order to determine when DD levels return to values obtained in non-pregnant women and can again be used in the exclusion of VTE.

PATIENTS AND METHODS

After uncomplicated pregnancies, 150 women delivering at term either vaginally (n = 100) or by cesarean section (n = 50) were included. DD levels were measured immediately following delivery and next at days 1, 3, 10, 30 and 45.

RESULTS

There was a marked elevation of DD at delivery, especially when instrumental. All DD measurements were above 500 ng mL(-1) at delivery, at day 1 and at day 3 postpartum. A sharp decrease in DD was observed between day 1 and day 3, followed by a slight increase at day 10. At day 30 and day 45, respectively, 79% and 93% of women in the vaginal delivery group and 70% and 83% in the cesarean group had levels below 500 ng mL(-1). Bleeding, breastfeeding and heparin prophylaxis did not modify DD levels significantly.

CONCLUSION

Using the Vidas DD new assay, our study provides reference intervals for DD in the postpartum period. Using a cut-off at 500 ng mL(-1), DD measurement for ruling out VTE was found to be useful again 4 weeks after delivery.

[Gynaecology-obstetrics. Invasive prenatal diagnosis and in utero surgical treatments: what is new?]

Early ultrasonographic antenatal diagnosis permits to perform intrauterine treatment to improve the prognosis of the fetus. These interventions are, however, invasive and associated with risks. In 2004, the results of the randomized trial comparing treatment options in the case of twin-to-twin transfusion syndrome were published. We summarize in this article the current knowledge on invasive fetal therapy.

Sonographic detection of fluid collections and postoperative morbidity following Cesarean section and hysterectomy

OBJECTIVES

To evaluate the clinical significance of sonographically detected fluid collections following Cesarean section and hysterectomy, and to identify risk factors associated with their formation.

METHODS

This was a prospective study including 280 women, 145 of whom had undergone a Cesarean section and 135 of whom had undergone abdominal or vaginal hysterectomy. Ultrasound examinations were carried out on all women on day 4 after surgery to assess the presence of abdominal wall or pelvic fluid collections. The sonographers were unaware of the clinical course before the examination and were not involved in any clinical decision-making. Ultrasound findings were correlated with clinical data and postoperative morbidity.

RESULTS

A fluid collection was found in 69 (48%) women after Cesarean section, and in 59 (44%) women who had undergone hysterectomy. No risk factors for the development of fluid collections after Cesarean section or hysterectomy were identified. The risk of developing febrile morbidity was not related to the presence, location or size of fluid collections.

CONCLUSIONS

Postoperative fluid collections are common after Cesarean section and hysterectomy. As fluid collections detected by sonography were not associated with postoperative morbidity, this finding is unlikely to be useful in the workup for postoperative fever.

Nitric oxide and portal hypertension: a nitric oxide-releasing derivative of ursodeoxycholic acid that selectively releases nitric oxide in the liver

Portal hypertension, a common consequence of chronic liver diseases, is directly responsible for most complications of cirrhosis. In liver microcirculation, nitric oxide is considered a major fine tuner of vascular tone by counterbalancing vasoconstrictors (sympathetic nervous activity, the renin-angiotensin system, and endothelin-1) in normal and cirrhotic livers. The deficiency of endothelial nitric oxide release is a key factor in the hemodynamic abnormalities associated with the dynamic component of portal hypertension. Conventional nitric oxide donors release nitric oxide into the blood stream, causing systemic hypotension and progression of vasodilatory syndrome in cirrhotic patients. NCX1000 is a nitric oxide-releasing derivative of ursodeoxycholic acid-derived compounds, being capable of selectively releasing nitric oxide into the liver circulation. Administration of NCX1000 to portal hypertensive rats decreases intrahepatic resistance providing a novel therapy for the treatment of portal hypertension.

Nitric oxide-releasing NSAIDs: a review of their current status

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely prescribed drugs worldwide owing to their anti-inflammatory, antipyretic and analgesic properties. However, their use is hampered by gastrointestinal (GI) toxicity, the most common drug-related serious adverse event in industrialised nations. Nitric oxide (NO)-releasing NSAIDs, a recently described class of drugs, are generated by adding a nitroxybutyl or a nitrosothiol moiety to the parent NSAID via a short-chain ester linkage. While efficacy of nitrosothiol-NO-NSAIDs still awaits investigation, nitroxybutyl-NO-NSAIDs have been extensively studied in animals, thus the abbreviation NO-NSAIDs used here refers to the latter group of NSAID derivatives. NO-NSAIDs retain the anti-inflammatory and antipyretic activity of original NSAIDs, although they exhibit markedly reduced gastrointestinal toxicity. NO-NSAIDs are nonselective cyclo-oxygenase (COX) inhibitors, and they also exert COX-independent activities that are NO-dependent. Indeed, NO-NSAIDs suppress production of the cytokines interleukin (IL)-1beta, IL-18 and interferon-gamma by causing the S-nitrosilation/inhibition of caspase-1. In acute and chronic animal models of inflammation, it has been demonstrated that NO-NSAIDs abrogated prostaglandin E2 as well as thromboxane B2 generation. In a murine model, NO-naproxen was approximately 10-fold more potent than naproxen in reducing animal writhing after intraperitoneal injection of acetic acid. Similar data have been obtained in chronic models of pain such as rat adjuvant arthritis. In vivo and in vitro studies suggest that NO-aspirin (acetylsalicylic acid) exerts more potent antithrombotic action than aspirin, probably by coupling the ability to inhibit COX-1 with the anti-adhesive effect of NO. Moreover, in a model of renal injury NO-flurbiprofen not only has been demonstrated to be devoid of nephrotoxicity but also to ameliorate renal function. Finally, in an animal model of chronic neurodegenerative disease, NO-flurbiprofen and NO-aspirin attenuated the brain inflammatory response. The GI toxicity of NO-flurbiprofen and NO-naproxen is currently being investigated in healthy individuals.

Cyclo-oxygenase isoenzymes. Structural basis for selective inhibition of cyclo-oxygenases by anti-inflammatory agents

Cyclo-oxygenase (prostaglandin endoperoxide synthase) is the enzyme which metabolizes the conversion of arachidonic acid to prostaglandin. It exists in at least two isoforms: the constitutive (cyclo-oxygenase-1) and the inducible (cyclo-oxygenase-2) which is controlled by a number of factors, including cytokines and intracellular messengers. These enzymes are the therapeutic targets of non-steroidal anti-inflammatory drugs such as aspirin and ibuprofen. The cyclo-oxygenase active site is a long, hydrophobic, channel where the substrate arachidonic acid gains access to the active site. Cyclo-oxygenase-2 differs form cyclo-oxygenase-1 in certain key characteristics, particularly important is the valine/leucine substitution at position 523 that creates a defect in the inner shell of the cyclo-oxygenase-2 enzyme channel leaving a side pocket by which drugs selective for cyclo-oxygenase-2 gain access. Although cyclo-oxygenase-1 seems to be expressed in physiological conditions and cyclo-oxygenase-2 in inflammatory conditions, it is not yet possible to identify all their different roles. Cyclo-oxygenase-2 may be expressed constitutively, whereas the generation of prostaglandin by cyclo-oxygenase-2 may replace that by cyclo-oxygenase-1 in some situations (or vice-versa). Both cyclo-oxygenase isoenzymes contribute to mucosal defence and the inhibition of the two isoforms contributes to the pathogenesis of non-steroidal anti-inflammatory drug-induced gastric damage.

Analgesia and cyclo-oxygenase inhibitors

Non-steroidal anti-inflammatory drugs are among the most commonly used medications and they are a mainstay in the treatment of inflammatory diseases. Non-steroidal anti-inflammatory drugs are widely used to reduce pain associated with acute or chronic inflammation. Recently, a new class of inhibitors of the inducible enzyme cyclo-oxygenase-2 have become available. These inhibitors selectively target the inducible enzyme and have been shown to spare the gastrointestinal tract. While a role of cyclo-oxygenase-2 in the development of chronic inflammation has been well established, its role in pain perception is still unclear. Recent experimental data led to the hypothesis that cyclo-oxygenase-1 plays an important role in pain perception. This short review addresses some recent preclinical data as well as some clinical evidence showing that cyclo-oxygenase-1 is an important component of inflammatory pain.

Mechanism of non-steroidal anti-inflammatory drug-gastropathy

Non-steroidal anti-inflammatory drugs are recognized to cause gastrointestinal damage impairing the defense ability of gastric mucosal barrier. A variety of mechanisms due to non-steroidal anti-inflammatory drugs direct irritant (topical) action and to their main pharmacological (systemic) effect, is involved in the pathogenesis of non-steroidal anti-inflammatory drugs induced gastropathy. The systemic activity comprises the inhibition of cyclo-oxygenase, but an increasing body of evidence suggests that cyclo-oxygenase-independent mechanisms are involved in the development of gastric injury. In line with this concept, neither cyclo-oxygenase-1 nor cyclo-oxygenase-2 deficient mice develop spontaneous gastrointestinal ulcers and pharmacological inhibition of cyclo-oxygenase-1 or cyclo-oxygenase-2 with selective inhibitors doesn't elicit gastrointestinal damage; suggesting that both isoforms of cyclo-oxygenase enzymes have to be inhibited to induce ulcers. Moreover non-steroidal anti-inflammatory drugs administration in rats, induces the systemic release of tumor necrosis factor-alpha and drives gastric epithelial cells to apoptosis activating the pro-apoptotic cascade of caspases. In response to non-steroidal anti-inflammatory drugs, neutrophils are recruited into the gastric microcirculation through a process that requires activation of adhesion molecules. Although there is virtually no information regarding the regulation of expression of gastric endothelial cell adhesion molecules in response to non steroidal anti-inflammatory drugs, the nuclear factor-kB may represent a potential modulator. Supporting this view, selective proteasome inhibitors inhibit nuclear translocation of nuclear factor-kB induced by tumor necrosis factor-alpha in human endothelial cells in vitro and reduce indomethacin-induced gastric mucosal injury in vivo.

NCX-1000, a NO-releasing derivative of ursodeoxycholic acid, selectively delivers NO to the liver and protects against development of portal hypertension

Portal hypertension resulting from increased intrahepatic resistance is a common complication of chronic liver diseases and a leading cause of death in patients with liver cirrhosis, a scarring process of the liver that includes components of both increased fibrogenesis and wound contraction. A reduced production of nitric oxide (NO) resulting from an impaired enzymatic function of endothelial NO synthase and an increased contraction of hepatic stellate cells (HSCs) have been demonstrated to contribute to high intrahepatic resistance in the cirrhotic liver. 2-(Acetyloxy) benzoic acid 3-(nitrooxymethyl) phenyl ester (NCX-1000) is a chemical entity obtained by adding an NO-releasing moiety to ursodeoxycholic acid (UDCA), a compound that is selectively metabolized by hepatocytes. In this study we have examined the effect of NCX-1000 and UDCA on liver fibrosis and portal hypertension induced by i.p. injection of carbon tetrachloride in rats. Our results demonstrated that although both treatments reduced liver collagen deposition, NCX-1000, but not UDCA, prevented ascite formation and reduced intrahepatic resistance in carbon tetrachloride-treated rats as measured by assessing portal perfusion pressure. In contrast to UDCA, NCX-1000 inhibited HSC contraction and exerted a relaxing effect similar to the NO donor S-nitroso-N-acetylpenicillamine. HSCs were able to metabolize NCX-1000 and release nitrite/nitrate in cell supernatants. In aggregate these data indicate that NCX-1000, releasing NO into the liver microcirculation, may provide a novel therapy for the treatment of patients with portal hypertension.

Low-amplitude propagated contractile waves: a relevant propulsive mechanism of human colon

BACKGROUND

Human colonic motility is still poorly understood, especially as far as concerns its propulsive function. Available data refer almost exclusively to the forceful propulsive activity, which is recognized as high-amplitude propagated contractions, the manometric equivalent of mass movements. By contrast, information on less vigorous propulsive contractions is still lacking.

AIMS

To investigate the presence and behaviour of low-amplitude propagated contractile waves (less than 50 mmHg in amplitude) in the colon of healthy humans during a 24-hour study period.

SUBJECTS AND METHODS

A series of 16 healthy volunteers of both sexes entered the study, and were investigated by a standard technique involving a colonoscopically-positioned manometric catheter. During the study, two standard 1,000 kcal mixed meal and a 450 kcal breakfast were served. The recordings were, therefore, scanned for the presence of low-amplitude propagated contractile waves (waves of less than 50 mmHg in amplitude, propagated over at least three consecutive recording ports), their daily distribution, and their relationship with physiological events.

RESULTS

Low-amplitude propagated contractile waves were constantly present in all the tracings, with an average of about 61 events/subject/day and a mean amplitude of about 20 mmHg. More than 80% of these events appeared during the day, with a significant (p<0.05) increase after meals and after morning awakening. In 25% of subjects, these waves were accompanied by emission of flatus.

CONCLUSIONS

In the human colon, low-amplitude propagated contractile waves are a constant physiological propulsive pattern, which is generally related to sleep-wake cycles and meal ingestion.

NO-aspirin protects from T cell-mediated liver injury by inhibiting caspase-dependent processing of Th1-like cytokines

BACKGROUND & AIMS

Concanavalin A (con A)-induced hepatitis is an immunomediated disease in which assembly of CD4(+) T cells and T helper (Th)1-like cytokines causes Fas-mediated liver cell death. Nitric oxide (NO) modulates Th1 response in vitro. NCX-4016 is an NO-aspirin derivative that spares the gastrointestinal tract and shares molecular targets with NO. The aim of this study was to investigate whether this NO-aspirin modulates Th1-like response induced by con A.

METHODS

BALB/c mice were injected with 0.3 mg con A per mouse alone or in combination with NO-aspirin (18-100 mg/kg) or aspirin (10-55 mg/kg).

RESULTS

NO-aspirin, but not aspirin, caused a dose-dependent protection against liver damage induced by con A. At a dose of 100 mg/kg, NO-aspirin caused a 40%-80% reduction of interleukin (IL)-1beta, IL-12, IL-18, interferon (IFN)-gamma, and tumor necrosis factor alpha production without affecting cytokine messenger RNA expression. NO-aspirin prevented Fas, Fas ligand, and IL-2 receptor up-regulation on spleen lymphocytes and Fas ligand on hepatocytes and caused the S-nitrosylation/inhibition of IL-1beta-converting enzyme-like cysteine proteases (caspases) involved in the processing and maturation of IL-1beta and IL-18. IL-18 immunoneutralization prevented IFN-gamma release and protected from liver injury induced by con A. In contrast to a selective caspase 1 inhibitor, zVAD.FMK, a pancaspase inhibitor, prevented IFN-gamma release and protected the liver from injury.

CONCLUSIONS

Th1-like response induced by con A is mediated by IL-18 and requires activation of multiple caspases. NCX-4016 causes the S-nitrosylation/inhibition of caspases involved in cytokine production. Inhibition of Th1-like response is a new anti-inflammatory mechanism of action of NO-aspirin.

Pathogenesis of non-steroidal anti-inflammatory drug gastropathy

Although non-steroidal anti-inflammatory drugs (NSAIDs) may impair the defensive ability of the gastric mucosal barrier through topical actions, recent evidence suggests that microcirculation disturbance plays a pivotal role in the genesis of gastric mucosal damage. In particular, attention has been drawn to the role exerted by those cytokine (TNF alpha and IL-1 beta) and adhesion molecules (LFA-1, Mac-1, ICAM-1) that regulate interactions between leukocyte and endothelial cells leading to gastric microvessels occlusion and ischaemic/hypoxic endothelial-epithelial cell damage. In recent years the role of prostaglandin synthesis inhibition in the pathogenesis of NSAID-gastropathy has been reconsidered, highlighting the immunomodulatory and pro-inflammatory consequences of prostanoids suppression. The awareness that mucosal damage is due to the non-discriminatory effect of NSAIDs on cyclo-oxygenase (COX) isoenzymes, has lead to the development of more selective, safer, COX-2 inhibitors. On the other hand, the observation that NO exerts a predominant physiological role in the maintenance of mucosal integrity has raised the opportunity to develop a new generation of NO-releasing NSAID derivatives with a reduced gastrointestinal toxicity.

Gastrointestinal safety of nitric oxide-derived aspirin is related to inhibition of ICE-like cysteine proteases in rats

BACKGROUND & AIMS

Caspases, a class of cysteine proteases, modulate apoptosis. Nitric oxide (NO)-releasing nonsteroidal anti-inflammatory drugs (NSAIDs) are a new class of NSAID derivatives with reduced gastrointestinal toxicity. The aim of this study was to investigate whether cysteine endoproteases are involved in the pathogenesis of NSAID gastropathy and are target for NO-aspirin (NCX-4016).

METHODS

Rats were treated orally with aspirin or equimolar doses of NCX-4016. Caspase activities were measured by fluorometric assay. Apoptosis was quantified by an enzyme-linked immunosorbent assay for histone-associated DNA, DNA ladder on agarose gel, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay. A primary culture of gastric chief cells was used to investigate whether NCX-4016 modulates guanosine 3',5'-cyclic monophosphate (cGMP)-dependent pathways.

RESULTS

Short- and long-term (7 days) aspirin administration resulted in a time- and dose-dependent gastric injury that was associated with apoptosis and caspase up-regulation. Z-VAD.FMK, a pancaspase inhibitor, and NO donors protected from acute damage induced by aspirin. NCX-4016 spared the gastric mucosa and caused caspase inactivation by S-nitrosylation. Inhibition of tumor necrosis factor (TNF)-alpha release or activity by TAPI-2 or anti-TNF-alpha receptor monoclonal antibodies protected against mucosal damage and caspase activation. NCX-4016 protected gastric chief cells from toxicity induced by TNF-alpha by activating cGMP-dependent pathways.

CONCLUSIONS

Aspirin administration leads to a TNF-alpha-dependent activation of gastric caspases. NO-aspirin spares the gastric mucosa and inhibits caspase activity through cGMP-dependent and -independent pathways.

Nitric oxide-releasing NSAIDs inhibit interleukin-1beta converting enzyme-like cysteine proteases and protect endothelial cells from apoptosis induced by TNFalpha

BACKGROUND

Nitric oxide (NO)-releasing NSAIDs are a new class of NSAID derivatives with markedly reduced gastrointestinal toxicity. Although it has been demonstrated that NO-NSAIDs spare gastric mucosal blood flow, molecular determinants involved in this effect are unknown.

AIM

To investigate the effect of aspirin, naproxen and flurbiprofen, and their NO-derivatives, on gastric apoptosis and endothelial cell damage induced by tumour necrosis factor-alpha (TNFalpha). In other systems, TNFalpha-induced apoptosis is mediated by caspases, a growing family of cysteine proteases similar to the IL-1beta converting enzyme (ICE), and so we have investigated whether NO-NSAIDs modulate ICE-like endopeptidases.

METHODS

Rats were treated orally with aspirin, naproxen and flurbiprofen, or their NO-releasing derivatives in equimolar doses, and were killed 3 h later to assess mucosal damage and caspase activity. Endothelial cells (HUVECs) were obtained from human umbilical cord by enzymatic digestion. Caspase 1 and 3 activities were measured by a fluorimetric assay using selective peptides as substrates and inhibitors. Apoptosis was quantified by ELISA specific for histone-associated DNA fragments and by the terminal transferase nick-end translation method (TUNEL).

RESULTS

In vivo NSAID administration caused a time-dependent increase in gastric mucosal damage and caspase activity. NCX-4016, NO-naproxen and NO-flurbiprofen did not cause any mucosal damage and prevented cysteine protease activation. NSAIDs and NO-NSAIDs stimulated TNFalpha release. Exposure to TNFalpha resulted in a time- and concentration-dependent HUVEC apoptosis, an effect that was prevented by pretreating the cells with NCX-4016, NO-naproxen, NO-flurbiprofen, SNP or Z-VAD.FMK, a pan-caspase inhibitor. The activation of ICE-like cysteine proteases was required to mediate TNFalpha-induced apoptosis of HUVECs. Exogenous NO donors inhibited TNFalpha-induced cysteine protease activation. Inhibition of caspase activity was due to S-nitrosylation of ICE/CPP32-like proteases. NO-NSAIDs prevented IL-1beta release from endotoxin-stimulated macrophages.

CONCLUSIONS

NO-releasing NSAIDs are a new class of non-peptide caspase inhibitors. Inhibition of ICE-like cysteine proteases prevents endothelial cell damage induced by pro-inflammatory agents and might contribute to the gastro-protective effects of NO-NSAIDs.

TNFalpha processing enzyme inhibitors prevent aspirin-induced TNFalpha release and protect against gastric mucosal injury in rats

BACKGROUND

Although previous studies indicate that prevention of tumour necrosis factor alpha (TNFalpha) release protects against NSAID-induced gastric mucosal injury, intracellular pathways by which aspirin causes TNFalpha release are unknown. TNFalpha is synthesized as a precursor which is proteolytically cleaved by a specific converting enzyme, TACE, to release the mature cytokine. TACE inhibitors prevent TNFalpha release and protect against TNFalpha-mediated disease.

AIM

To investigate: (i) molecular events that regulate TNFalpha secretion in response to aspirin in vivo and in vitro; (ii) whether TNFalpha secretion inhibitors prevent aspirin-induced TNFalpha release and protect against gastric mucosal damage; and (iii) whether TNFalpha exerts a direct cytotoxic effect on gastric epithelial cells.

METHODS

In vitro studies were carried out on mouse macrophages and rat gastric mucosal cells. Gastric mucosal damage was induced in rats by oral administration of 300 mg/kg aspirin. TNFalpha cytotoxicity on gastric mucosal cells was examined by treating rats with lipopolysaccharide to release TNFalpha or by incubating dispersed gastric mucosal cells with increasing concentrations of TNFalpha.

RESULTS

Aspirin increases intracellular calcium (Ca2+) levels and causes a time and concentration dependent increase in macrophage TNFalpha mRNA accumulation and cytokine release. Agents that cause Ca2+ mobilization with a receptor-independent mechanism, such as ionomycin and thapsigargin, stimulate TNFalpha release. Incubating the macrophages in a Ca2+ free medium inhibited TNFalpha secretion. Agents that prevent TNFalpha mRNA transcription, e.g. lisophylline, PGE2, interleukin-10 and 8-BrcAMP, or TACE inhibitors, e.g. EDTA, TAPI-2 and BB-3103, inhibit TNFalpha release and protect rats against gastric mucosal injury induced by oral administration of aspirin. TNFalpha exerts a direct cytotoxic effect on gastric epithelial cells as demonstrated by the reduced viability observed in gastric mucosal cells prepared from rats treated with lipopolysaccharide, or directly incubated with increasing concentrations of TNFalpha.

CONCLUSIONS

(i) Aspirin directly stimulates TNFalpha gene transcription; (ii) TACE inhibitors protect against aspirin-induced gastric mucosal injury; and (iii) TNFalpha exerts a direct cytotoxic effect on gastric epithelial cells.