Dose-related inhibition of proinflammatory cytokine release from neutrophils of the newborn by dexamethasone, betamethasone, and hydrocortisone

Plasma exchange and glucocorticoids to delay death or end-stage renal disease in anti-neutrophil cytoplasm antibody-associated vasculitis: PEXIVAS non-inferiority factorial RCT

BACKGROUND

Anti-neutrophil cytoplasm antibody-associated vasculitis is a multisystem, autoimmune disease that causes organ failure and death. Physical removal of pathogenic autoantibodies by plasma exchange is recommended for severe presentations, along with high-dose glucocorticoids, but glucocorticoid toxicity contributes to morbidity and mortality. The lack of a robust evidence base to guide the use of plasma exchange and glucocorticoid dosing contributes to variation in practice and suboptimal outcomes.

OBJECTIVES

We aimed to determine the clinical efficacy of plasma exchange in addition to immunosuppressive therapy and glucocorticoids with respect to death and end-stage renal disease in patients with severe anti-neutrophil cytoplasm antibody-associated vasculitis. We also aimed to determine whether or not a reduced-dose glucocorticoid regimen was non-inferior to a standard-dose regimen with respect to death and end-stage renal disease.

DESIGN

This was an international, multicentre, open-label, randomised controlled trial. Patients were randomised in a two-by-two factorial design to receive either adjunctive plasma exchange or no plasma exchange, and either a reduced or a standard glucocorticoid dosing regimen. All patients received immunosuppressive induction therapy with cyclophosphamide or rituximab.

SETTING

Ninety-five hospitals in Europe, North America, Australia/New Zealand and Japan participated.

PARTICIPANTS

Participants were aged ≥ 16 years with a diagnosis of granulomatosis with polyangiitis or microscopic polyangiitis, and either proteinase 3 anti-neutrophil cytoplasm antibody or myeloperoxidase anti-neutrophil cytoplasm antibody positivity, and a glomerular filtration rate of < 50 ml/minute/1.73 m2 or diffuse alveolar haemorrhage attributable to active anti-neutrophil cytoplasm antibody-associated vasculitis.

INTERVENTIONS

Participants received seven sessions of plasma exchange within 14 days or no plasma exchange. Oral glucocorticoids commenced with prednisolone 1 mg/kg/day and were reduced over different lengths of time to 5 mg/kg/day, such that cumulative oral glucocorticoid exposure in the first 6 months was 50% lower in patients allocated to the reduced-dose regimen than in those allocated to the standard-dose regimen. All patients received the same glucocorticoid dosing from 6 to 12 months. Subsequent dosing was at the discretion of the treating physician.

PRIMARY OUTCOME

The primary outcome was a composite of all-cause mortality and end-stage renal disease at a common close-out when the last patient had completed 10 months in the trial.

RESULTS

The study recruited 704 patients from June 2010 to September 2016. Ninety-nine patients died and 138 developed end-stage renal disease, with the primary end point occurring in 209 out of 704 (29.7%) patients: 100 out of 352 (28%) in the plasma exchange group and 109 out of 352 (31%) in the no plasma exchange group (adjusted hazard ratio 0.86, 95% confidence interval 0.65 to 1.13; p = 0.3). In the per-protocol analysis for the non-inferiority glucocorticoid comparison, the primary end point occurred in 92 out of 330 (28%) patients in the reduced-dose group and 83 out of 325 (26%) patients in the standard-dose group (partial-adjusted risk difference 0.023, 95% confidence interval 0.034 to 0.08; p = 0.5), thus meeting our non-inferiority hypothesis. Serious infections in the first year occurred in 96 out of 353 (27%) patients in the reduced-dose group and in 116 out of 351 (33%) patients in the standard-dose group. The rate of serious infections at 1 year was lower in the reduced-dose group than in the standard-dose group (incidence rate ratio 0.69, 95% confidence interval 0.52 to 0.93; p = 0.016).

CONCLUSIONS

Plasma exchange did not prolong the time to death and/or end-stage renal disease in patients with anti-neutrophil cytoplasm antibody-associated vasculitis with severe renal or pulmonary involvement. A reduced-dose glucocorticoid regimen was non-inferior to a standard-dose regimen and was associated with fewer serious infections.

FUTURE WORK

A meta-analysis examining the effects of plasma exchange on kidney outcomes in anti-neutrophil cytoplasm antibody-associated vasculitis is planned. A health-economic analysis of data collected in this study to examine the impact of both plasma exchange and reduced glucocorticoid dosing is planned to address the utility of plasma exchange for reducing early end-stage renal disease rates. Blood and tissue samples collected in the study will be examined to identify predictors of response to plasma exchange in anti-neutrophil cytoplasm in antibody-associated vasculitis. The benefits associated with reduced glucocorticoid dosing will inform future studies of newer therapies to permit further reduction in glucocorticoid exposure. Data from this study will contribute to updated management recommendations for anti-neutrophil cytoplasm antibody-associated vasculitis.

LIMITATIONS

This study had an open-label design which may have permitted observer bias; however, the nature of the end points, end-stage renal disease and death, would have minimised this risk. Despite being, to our knowledge, the largest ever trial in anti-neutrophil cytoplasm antibody-associated vasculitis, there was an insufficient sample size to assess clinically useful benefits on the separate components of the primary end-point: end-stage renal disease and death. Use of a fixed-dose plasma exchange regimen determined by consensus rather than data-driven dose ranging meant that some patients may have been underdosed, thus reducing the therapeutic impact. In particular, no biomarkers have been identified to help determine dosing in a particular patient, although this is one of the goals of the biomarker plan of this study.

TRIAL REGISTRATION

This trial is registered as ISRCTN07757494, EudraCT 2009-013220-24 and Clinicaltrials.gov NCT00987389.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 38. See the NIHR Journals Library website for further project information.

Effects of postnatal hydrocortisone on cytokine profile in extremely preterm infants

BACKGROUND

Systemic hydrocortisone administration has been widely used in preterm infants who are at risk of bronchopulmonary dysplasia (BPD). However, the effects of hydrocortisone on cytokine profiles have not been examined. We aimed to investigate the effects of postnatal hydrocortisone treatment on serum cytokine levels in extremely preterm infants.

METHODS

This is a retrospective study of 29 extremely preterm infants born at <28 weeks of gestational age. We obtained serum from blood samples collected during an early phase (5-20 days) and a late phase (28-60 days) after birth. We measured the levels of proinflammatory cytokines (tumor necrosis factors α and β, interleukin (IL)-1β, and IL-6), T-helper (Th) 1 cytokines (interferon-γ, IL-2, and IL-12p70), Th2 cytokines (IL-4, IL-5, and IL-10), Th17 cytokine IL-17A, and chemokine IL-8. The cytokine levels between the early and late phases were compared between infants who received postnatal hydrocortisone and those who did not.

RESULTS

Thirteen infants (45%) received systemic hydrocortisone treatment at a median age of 15 days (IQR: 10.0-21.5) after birth due to respiratory deterioration. The percentage of BPD was higher in the steroid group than in the non-steroid group (P = 0.008). The ratio of IL-6 for the late-to-early phase was significantly lower in the steroid group than in the non-steroid group (P = 0.04). The concentration of the other cytokines remained unchanged between the phases.

CONCLUSIONS

Although the postnatal hydrocortisone treatment provided for respiratory deterioration did not prevent the BPD development, hydrocortisone treatment might suppress IL-6 overproduction in extremely preterm infants.

Immune System Remodelling by Prenatal Betamethasone: Effects on β-Cells and Type 1 Diabetes

Type 1 diabetes (T1D) is a multifactorial disease of unknown aetiology. Studies focusing on environment-related prenatal changes, which might have an influence on the development of T1D, are still missing. Drugs, such as betamethasone, are used during this critical period without exploring possible effects later in life. Betamethasone can interact with the development and function of the two main players in T1D, the immune system and the pancreatic β-cells. Short-term or persistent changes in any of these two players may influence the initiation of the autoimmune reaction against β-cells. In this review, we focus on the ability of betamethasone to induce alterations in the immune system, impairing the recognition of autoantigens. At the same time, betamethasone affects β-cell gene expression and apoptosis rate, reducing the danger signals that will attract unwanted attention from the immune system. These effects may synergise to hinder the autoimmune attack. In this review, we compile scattered evidence to provide a better understanding of the basic relationship between betamethasone and T1D, laying the foundation for future studies on human cohorts that will help to fully grasp the role of betamethasone in the development of T1D.

A comparison of 7-day versus 10-day course of low-dose dexamethasone for chronically ventilated preterm infants

OBJECTIVE

The objective of the study was to compare the effect of two different dexamethasone regimens on respiratory outcomes of ventilator-dependent preterm infants.

STUDY DESIGN

Retrospective study of ventilated preterm infants <29 weeks gestational age treated with either 7-day or 10-day dexamethasone course. Primary outcome was days to successful extubation. Other outcomes included rate of successful extubation and need for repeat steroid therapy.

RESULTS

Fifty-nine infants were identified; 32 (54%) received 7 days of dexamethasone and 27 (46%) received 10 days of dexamethasone. Both groups had comparable baseline demographics and clinical characteristics. Mean time to successful extubation was similar between the two groups (5.1±2.7 days in 7-day group and 6.0±3.7 days in 10-day group, P=0.42). Successful extubation by end of treatment (56% versus 67%, P=0.44) and need for repeat steroid therapy (47% versus 33%, P=0.43) were also similar.

CONCLUSION

7-day and 10-day course of dexamethasone have comparable efficacy in facilitating extubation of ventilator-dependent preterm infants.

Plasma exchange and glucocorticoid dosing in the treatment of anti-neutrophil cytoplasm antibody associated vasculitis (PEXIVAS): protocol for a randomized controlled trial

BACKGROUND

Granulomatosis with polyangiitis (GPA, Wegener's) and microscopic polyangiitis (MPA) are small vessel vasculitides collectively referred to as anti-neutrophil cytoplasm antibody-associated vasculitis (AAV). AAV is associated with high rates of morbidity and mortality due to uncontrolled disease and treatment toxicity. Small randomized trials suggest adjunctive plasma exchange may improve disease control, while observational evidence suggests that current oral glucocorticoid doses are associated with severe infections in patients with AAV. A randomized study of both plasma exchange and glucocorticoids is required to evaluate plasma exchange and oral glucocorticoid dosing in patients with AAV.

METHODS/DESIGN

PEXIVAS is a two-by-two factorial randomized trial evaluating adjunctive plasma exchange and two oral glucocorticoid regimens in severe AAV. Five hundred patients are being randomized at centers across Europe, North America, Asia, and Australasia to receive plasma exchange or no plasma exchange, and to receive standard or reduced oral glucocorticoid dosing. All patients receive immunosuppression with either cyclophosphamide or rituximab. The primary outcome is the time to the composite of all-cause mortality and end-stage renal disease.PEXIVAS is funded by the National Institute of Health Research (UK), the Food and Drug Administration (USA), the National Institutes of Health (USA), the Canadian Institute of Health Research (Canada), the National Health and Medical Research Council (Australia), and Assistance Publique (France). Additional in-kind supplies for plasma exchange are provided by industry partners (TerumoBCT, Gambro Australia, and Fresenius Australia).

DISCUSSION

This is the largest trial in AAV undertaken to date. PEXIVAS will inform the future standard of care for patients with severe AAV. The cooperation between investigators, funding agencies, and industry provides a model for conducting studies in rare diseases.

TRIAL REGISTRATION

Current Controlled Trials: (ISRCTN07757494) and clinicaltrials.gov: (NCT00987389).

Dexamethasone and RU24858 Induce Survival and Growth Factor Receptor Bound Protein 2, Leukotriene B4 Receptor 1 and Annexin-1 Expression in Primary Human Neutrophils

Glucocorticoids are widely used anti-inflammatory medication in diseases like asthma and chronic obstructive pulmonary disease. Glucocorticoids can either activate (transactivation) or inhibit (transrepression) transcription. RU24858 was introduced as a “dissociated” glucocorticoid and it has been reported to transrepress but not to transactivate. The aim of this study was to compare the effects of RU24858 and dexamethasone in human neutrophils. RU24858 delayed spontaneous neutrophil apoptosis and further enhanced GM-CSF- induced neutrophil survival to a similar extent as dexamethasone. Like dexamethasone RU24858 also reduced CXCL8 and MIP-1α. Unexpectedly however, RU24858 increased the expression of the glucocorticoid-inducible genes BLT-1, Annexin-1 and Grb-2 in neutrophils to a similar level as seen with dexamethasone. We have shown here that dexamethasone and RU24858 both increase Grb-2, BLT1 and Annexin-1 expression and inhibit CXCL8 and MIP-1α production. This suggests that RU24858 was not able to dissociate between transactivation and transrepression in human neutrophils but enhanced neutrophil survival.

Exogenous porcine surfactants increase the infiltration of leukocytes in the lung of rats

BACKGROUND

Several studies have investigated the influence of exogenous surfactants on inflammatory response in the lung, however results reported about effects of surfactants on the lung infiltration of leukocytes are controversial. Our previous study noticed that treatment of porcine surfactant (PS) significantly increased the lung infiltration of leukocytes in rats with acute lung injury (ALI). The objective of this study was to verify the effect of exogenous PS on the lung infiltration of leukocytes in vivo and investigate the possible mechanisms involved in vitro.

METHODS

The number of leukocytes in bronchoalveolar lavage fluid (BALF) of rats with or without lipopolysaccharide (LPS)-induced ALI was determined after treatment with different concentrations of PS, dexamethasone (Dex) or PS + Dex. The effect of PS and Curosurf, a commercially available porcine surfactant, on human peripheral neutrophil migration was determined by the Boyden Chamber Assay.

RESULTS

Instillation of PS significantly increased the number of leukocytes in BALF of normal rats and rats with LPS-induced ALI. Most of the increased leukocytes were neutrophils. Dex significantly decreased the number of leukocytes and TNF-alpha concentration in BALF caused by LPS, but did not significantly reduce the number of leukocytes increased by PS. In vitro experiments further demonstrated that both PS and Curosurf had direct chemotactic effects on neutrophils.

CONCLUSIONS

These results suggest that PS contain chemoattractant(s) which induce the infiltration of leukocytes, especially neutrophils, into lung.

NFkappaB is persistently activated in continuously stimulated human neutrophils

Increased activation of the transcription factor NFkappaB in the neutrophils has been associated with the pathogenesis of sepsis, acute lung injury (ALI), bronchopulmonary dysplasia (BPD), and other neutrophil-mediated inflammatory disorders. Despite recent progress in analyzing early NFkappaB activation in human neutrophils, activation of NFkappaB in persistently stimulated neutrophils has not been previously studied. Because it is the persistent NFkappaB activation that is thought to be involved in the host response to sepsis and the pathogenesis of ALI and BPD, we hypothesized that continuously stimulated human neutrophils may exhibit a late phase of NFkappaB activity. The goal of this study was to analyze the NFkappaB activation and expression of IkappaB and NFkappaB proteins during neutrophil stimulation with inflammatory signals for prolonged times. We demonstrate that neutrophil stimulation with lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNFalpha) induces, in addition to the early activation at 30-60 min, a previously unrecognized late phase of NFkappaB activation. In LPS-stimulated neutrophils, this NFkappaB activity typically had a biphasic character, whereas TNFalpha-stimulated neutrophils exhibited a continuous NFkappaB activity peaking around 9 h after stimulation. In contrast to the early NFkappaB activation that inversely correlates to the nuclear levels of IkappaBalpha, however, in continuously stimulated neutrophils, NFkappaB is persistently activated despite considerable levels of IkappaBalpha present in the nucleus. Our data suggest that NFkappaB is persistently activated in human neutrophils during neutrophil-mediated inflammatory disorders, and this persistent NFkappaB activity may represent one of the underlying mechanisms for the continuous production of proinflammatory mediators.

NFkappaB is persistently activated in continuously stimulated human neutrophils

Increased activation of the transcription factor NFkappaB in the neutrophils has been associated with the pathogenesis of sepsis, acute lung injury (ALI), bronchopulmonary dysplasia (BPD), and other neutrophil-mediated inflammatory disorders. Despite recent progress in analyzing early NFkappaB activation in human neutrophils, activation of NFkappaB in persistently stimulated neutrophils has not been previously studied. Because it is the persistent NFkappaB activation that is thought to be involved in the host response to sepsis and the pathogenesis of ALI and BPD, we hypothesized that continuously stimulated human neutrophils may exhibit a late phase of NFkappaB activity. The goal of this study was to analyze the NFkappaB activation and expression of IkappaB and NFkappaB proteins during neutrophil stimulation with inflammatory signals for prolonged times. We demonstrate that neutrophil stimulation with lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNFalpha) induces, in addition to the early activation at 30-60 min, a previously unrecognized late phase of NFkappaB activation. In LPS-stimulated neutrophils, this NFkappaB activity typically had a biphasic character, whereas TNFalpha-stimulated neutrophils exhibited a continuous NFkappaB activity peaking around 9 h after stimulation. In contrast to the early NFkappaB activation that inversely correlates to the nuclear levels of IkappaBalpha, however, in continuously stimulated neutrophils, NFkappaB is persistently activated despite considerable levels of IkappaBalpha present in the nucleus. Our data suggest that NFkappaB is persistently activated in human neutrophils during neutrophil-mediated inflammatory disorders, and this persistent NFkappaB activity may represent one of the underlying mechanisms for the continuous production of proinflammatory mediators.

Interleukin-10 production after pro-inflammatory stimulation of neutrophils and monocytic cells of the newborn. Comparison to exogenous interleukin-10 and dexamethasone levels needed to inhibit chemokine release

BACKGROUND

Neutrophils followed by monocytic cells are recruited into the lung during the early development of bronchopulmonary dysplasia (BPD).

OBJECTIVES

We determined: (1) the capacity of polymorphonuclear leukocytes (PMNs) and peripheral blood monocytic cells (PBMCs) of the newborn to produce and release the anti-inflammatory cytokine, interleukin (IL)-10, after stimulation by lipopolysaccharide (LPS) or tumor necrosis factor (TNF), and (2) the levels of exogenous IL-10 and/or dexamethasone (DEX) needed to inhibit the release of the pro-inflammatory chemokine IL-8 from stimulated cells.

METHODS

PMNs and PBMCs were isolated from cord blood of healthy term infants. RT-PCR and ELISA were used to detect mRNA and cytokine levels from culture media, respectively.

RESULTS

We found that PMNs did not produce IL-10 mRNA or release IL-10 but did produce IL-8 mRNA by 1 h. PBMCs did produce IL-10 mRNA after 4 h (with IL-8 mRNA expression by 1 h). LPS-stimulated PBMCs released IL-10 to a maximum of 1,038 pg/ml/5 million cells (56 femtomolar). Equimolar doses of exogenous IL-10 or DEX produced up to 83% inhibition of IL-8 from PMNs. Exogenous IL-10 was more potent than DEX, on an equimolar basis, with regard to IL-8 release from PBMCs (90 vs. 33% respectively at a 10 nanomolar level). No inhibition of IL-8 release by IL-10 or DEX was observed at 100 femtomolar level. IL-10 and DEX did not have an additive inhibitory effect on IL-8 release.

CONCLUSIONS

We conclude that for the newborn: (1) PBMCs produce IL-10 far below the level needed to inhibit a submaximal release of IL-8 from PMNs or PBMCs, and (2) exogenous IL-10 was equipotent or more potent than therapeutic levels of DEX on inhibition of IL-8 from these cells. Further studies are needed to determine if exogenous IL-10 may be useful in the treatment of BPD or other inflammatory disorders of the newborn.

Proinflammatory cytokine levels in saliva before and after treatment of (erosive) oral lichen planus with dexamethasone

OBJECTIVE

To explore the potential of detecting the level of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-1-alpha (IL-1-alpha), IL-6, and IL-8 in whole unstimulated saliva (WUS) in monitoring the therapeutic effects of topical dexamethasone on these salivary cytokines in subjects with erosive oral lichen planus (OLP).

STUDY DESIGN

Thirteen definitively diagnosed OLP subjects were enrolled in the study as were 13 age- and sex-matched controls. The OLP subjects were treated with 0.1% dexamethasone oral rinse for 6 weeks. Prior to treatment and at the end of clinical trial, the visual analog scale (VAS) for symptoms was recorded, WUS was collected and these proinflammatory cytokines were analyzed by ELISA.

RESULTS

Following the dexamethasone treatment, the levels of TNF-alpha, IL-1-alpha, IL-6, and IL-8 were decreased significantly, and IL-1-alpha and IL-8 were detected at a level without a statistically significant difference from controls. VAS value was decreased significantly and was found to significantly correlate with the decrease in IL-1-alpha and IL-8 levels.

CONCLUSIONS

These preliminary results indicate that salivary analysis of NF-kappaB-dependent cytokines may be applied to monitoring the therapeutic response of OLP.

Effect of dexamethasone on B7 regulation and T cell activation in neonates and adults

The safety of dexamethasone for neonates has been questioned, partly because of its multiple unspecific effects on the immune system. Specific effects of dexamethasone on co-stimulatory and immune suppressive functions of neonatal compared with adult macrophages (MPhi) are not known. We evaluated the effect of dexamethasone on the expression and regulation of MPhi B7 family receptors (B7-1, CD80; B7-2, CD86) and on their ability to co-stimulate T cells. Cord blood macrophages (CBMPhi) and MPhi from healthy adults (PBMPhi) were isolated, and cell surface markers were phenotyped by flow cytometry. In tissue culture, cells were exposed to dexamethasone, interferon-gamma (IFN-gamma), cAMP, or a T cell mitogen (alphaCD3) and examined for their capacity to activate or destroy T cells. CBMPhi were less able to up-regulate CD80 and CD86 than PBMPhi (p < 0.05). Dexamethasone inhibited the up-regulation of CD80, CD86, and HLA-DR on PBMPhi and even more so on CBMPhi (p < 0.05 versus PBMPhi for CD80 and CD86). In the presence of dexamethasone, stimulation with alphaCD3 MAb enhanced cytotoxic functions of PMBMPhi and CB(mu)phi with an increase in deleted T cells, a reduced fraction of enlarged T cells, and an inhibition of T cell CD28 up-regulation, which again were more pronounced with CBMPhi (p < 0.05 versus PBMPhi). In conclusion, neonatal MPhi are exquisitely sensitive to the inhibitory effects of dexamethasone on B7 expression. Although perhaps producing the desired therapeutic effect, dexamethasone may do so in newborns at the expense of a near complete paralysis of MPhi-dependent T cell function.

Therapeutic potential of macrolide immunosuppressants in dermatology

Dermatologists are frequently presented with inflammatory dermatoses that are responsive to treatment with immunomodulating drugs. Corticosteroids, particularly when applied topically, have been the mainstay of treatment in the past. Their undoubted efficacy, however, has been undermined by problems with repeated use including tachyphylaxis and side effects such as skin atrophy and hypertension. Macrolide immunosuppressive drugs, originally used for prophylaxis of organ transplant rejection, have been shown to be effective in the treatment of inflammatory dermatoses. The original drugs used in dermatology in this class have their own limitations including poor absorption when used topically and their distinct side-effect profiles. A search for other immunosuppressive macrolide antibiotics has led to the development of new agents, which have enhanced profiles for the treatment of skin disease. This review discusses the main dermatoses that may be targeted by this class of drugs and summarises the topical and systemic macrolides either currently in use, in clinical trials or preclinical development.

The novel phosphodiesterase 4 inhibitor, CI-1044, inhibits LPS-induced TNF-alpha production in whole blood from COPD patients

Chronic obstructive pulmonary disease (COPD) is a common, progressive respiratory disease that causes great morbidity and mortality despite treatment. Tumor necrosis factor alpha (TNF-alpha) plays a central role as a pro-inflammatory cytokine in COPD. TNF-alpha release is markedly inhibited by phosphodiesterase type 4 (PDE4) inhibitors that have proven efficacious in COPD clinical trials. The aim of this study was to compare the in vitro activities of the novel selective PDE4 inhibitors CI-1044 compared to well-known PDE4 inhibitors, rolipram and cilomilast, and to the glucocorticoid dexamethasone at reducing lipopolysaccharide (LPS)-induced TNF-alpha release in whole blood from COPD patients and healthy subjects. In the whole blood from COPD patients pre-incubation with PDE4 inhibitors or dexamethasone resulted in a dose-dependent inhibition of LPS-induced TNF-alpha release with IC(50) values of 1.3+/-0.7, 2.8+/-0.9 microM, higher to 10 microM and lesser than 0.03 microM for CI-1044, rolipram, cilomilast and dexamethasone, respectively. We observed a similar inhibition in the whole blood from healthy volunteers with, however, higher IC(50) values. These results indicate that CI-1044 inhibits in vitro LPS-induced TNF-alpha release in whole blood from COPD patients better than rolipram and cilomilast and suggested that it could be a useful anti-inflammatory therapy in COPD.

Interleukin-10 inhibits proinflammatory chemokine release by neutrophils of the newborn without suppression of nuclear factor-kappa B

An increase in polymorphonuclear leukocytes (PMNs) and proinflammatory chemokines, such as IL-8 and macrophage inflammatory protein-1 alpha (MIP), are found in the airways during early stages of bronchopulmonary dysplasia. We determined whether IL-10 produces a dose-related inhibition of proinflammatory chemokine release from stimulated neutrophils of the newborn and whether the mechanism involves the pivotal transcription factor, nuclear factor-kappa B. PMNs isolated from the cord blood of healthy newborns were stimulated submaximally with either lipopolysaccharide (n = 5) or tumor necrosis factor (n = 4), with and without IL-10 (0.01-1000 ng/mL). IL-8 and MIP release were measured in cell culture supernatants at 18 h. The presence or absence of nuclear factor-kappa B activity and inhibitor-kappa B alpha degradation was measured at 30 min and 3 h after PMN stimulation began. During lipopolysaccharide stimulation, IL-10 significantly reduced IL-8 levels from 50 +/- 16 ng/mL to 7 +/- 3 ng/mL, and MIP levels from 14 +/- 5 to 0.7 +/- 0.1 ng/mL (mean +/- SEM, p < 0.01). IL-10 produced an insignificant reduction in IL-8 and MIP levels after stimulation of PMNs with tumor necrosis factor. IL-10 did not inhibit nuclear factor-kappa B activation and inhibitor-kappa B alpha degradation in PMNs stimulated with tumor necrosis factor or lipopolysaccharide for 30 min. After PMN stimulation for 3 h, inhibitor-kappa B alpha cytoplasmic levels were restored; however, they were unaffected by IL-10. We conclude that IL-10 is a potent inhibitor of lipopolysaccharide-stimulated release of IL-8 and MIP from neutrophils of the newborn via a mechanism not involving nuclear factor-kappa B activity. Further work is needed to determine whether exogenous IL-10 may be useful for suppressing inflammation in bronchopulmonary dysplasia.

Okadaic acid induces sustained activation of NFkappaB and degradation of the nuclear IkappaBalpha in human neutrophils

Human neutrophils differ from other cells by containing high amount of IkappaBalpha in the nucleus, and this increased nuclear IkappaBalpha accumulation is associated with the inhibition of NFkappaB activity and increased apoptosis. However, the mechanisms regulating NFkappaB activation and IkappaBalpha degradation in human neutrophils are little understood. The objective of this study was to provide a further insight into the mechanisms regulating NFkappaB activity and IkappaBalpha degradation in human neutrophils. We show that okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, induces sustained activation of NFkappaB and degradation of the nuclear IkappaBalpha, and increases interleukin-8 expression in the neutrophils. Furthermore, inhibitors of protein kinase C-delta (PKCdelta) and IkappaB kinase (IKK) inhibit the OA-induced activation of NFkappaB. Collectively, our results indicate that in human neutrophils, the sustained activation of NFkappaB is regulated by a continuous phosphorylation and degradation of the nuclear IkappaBalpha.