Development of the First Disease Activity Index for Eosinophilic Esophagitis: Update on the EEsAI in 2011

Background a nd Aims: T he international E EsAI study g roupis currently developing the first activity index (EEsAI) specificfor Eosinophilic Esophagitis (EoE). Goal: To develop, evaluateand validate the EEsAI.Methods: T he d evelopment comprises three phases: 1.Selection of candidate items; 2. Evaluation of the activity indexin a f irst patient cohort; and 3. V alidation in a s econd EoEpatient cohort. Focus group interviews with patients were usedin p hase 1 to generate p atient r eported outcomes ( PRO)according to guidelines o f regulatory authorities ( FDA andEMA), whereas the section of biologic items was developed byDelphi r ounds of i nternational E oE experts from E urope andNorth America.Results: The EEsAI has a modular composition to assess thefollowing components o f EoE activity: p atient reportedoutcomes, endoscopic activity, histologic activity, laboratoryactivity, a nd quality of life. D efinitions f or all aspects o fendoscopic and histologic appearance were established byconsensus rounds among EoE experts. Symptom assessmenttools were created that take into account d ifferent foodconsistencies as w ell as f ood avoidance and specificprocessing strategies. T he EEsAI is evaluated in a c ohort ofadult EoE patients since March 2011.Conclusions: After successful validation, the EEsAI will allowto standardize outcome assessment in E oE t rials which w illlikely lead to its wide applicability.

Cysteine 230 is essential for the structure and activity of the cytotoxic ligand TRAIL.

Unlike other tumor necrosis factor family members, the cytotoxic ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo-2L contains an unpaired cysteine residue (Cys(230)) in its receptor-binding domain. Here we show that the biological activity of both soluble recombinant TRAIL and cell-associated, full-length TRAIL is critically dependent on the presence of Cys(230). Mutation of Cys(230) to alanine or serine strongly affected its ability to kill target cells. Binding to its receptors was decreased by at least 200-fold, and the stability of its trimeric structure was reduced. In recombinant TRAIL, Cys(230) was found engaged either in interchain disulfide bridge formation, resulting in poorly active TRAIL, or in the chelation of one zinc atom per TRAIL trimer in the active, pro-apoptotic form of TRAIL.

Role of MIF and glutathione, in association with fetal ovine globin chain (Hbgamma) and LPS, in induction of TNFalpha from cells of young and aged mice, and PBL from healthy human populations.

Previous reports from our group have established that the fetal ovine gamma globin chain (Hbgamma) and LPS can synergize in the induction of pro-inflammatory cytokines, especially TNFalpha, from mouse and human leukocytes. A fetal sheep liver extract (FSLE) which was observed to have marked immunoregulatory properties in vivo and in vitro had independently been observed to contain significant amounts of each of these molecules. However, the biological activity of this extract (hereafter FSLE) was not explained solely by its content of Hbgamma and LPS, and independent analysis confirmed also the presence of migration inhibitory factor, MIF, and glutathione in FSLE. We have investigated whether MIF and the cellular anti-oxidant glutathione can further synergize with Hbgamma and LPS in TNFalpha induction from human cells in vitro, and mouse cells activated in vivo/in vitro. Our data show that indeed there is evidence for such a synergy. Treatment or mouse cells with FSLE produced an enhanced TNFalpha production which could be inhibited independently both by anti-Hbgamma and by anti-MIF, and optimally by a combination of these reagents.

Maturation protéolytique et sécrétion de la rénine: importance fonctionnelle de la pro-région

RÉSUMÉ Le système rénine-angiotensine joue un rôle prépondérant dans la régulation de la pression sanguine et de la balance des sels ainsi que dans d'autres processus physiologiques et pathologiques. Lorsque la pression sanguine est trop basse, les cellules juxtaglomérulaires sécrètent la rénine, qui clivera l'angiotensinogène circulant (sécrété majoritairement par le foie) pour libérer l'angiotensine I, qui sera alors transformée en angiotensine II par l'enzyme de conversion de l'angiotensine. Ce système est régulé au niveau de la sécrétion de la rénine par le rein. La rénine est une enzyme de type protéase aspartique. Elle est produite sous la forme d'un précurseur inactif de haut poids moléculaire appelé prorénine, qui peut être transformé en rénine active. Si le rôle de la prorégion de la rénine n'est pas encore connu, plusieurs études ont montré qu'elle pourrait être un auto-inhibiteur. Des travaux menés sur d'autres enzymes protéolytique ont mis en évidence un rôle de chaperon de leurs prorégions. Dans la circulation, la prorénine est majoritaire (90%) et la rénine active ne représente que 10% de la rénine circulante. L'enzyme qui transforme, in vivo, la prorénine en rénine active n'est pas connue. De même, l'endroit précis du clivage n'est pas élucidé. Dans ce travail, nous avons généré plusieurs mutants de la prorénine et les avons exprimés dans deux types cellulaires : les CV1 (modèle constitutif) et AtT-20 (modèle régulé). Nous avons montré que la prorégion joue un rôle important aussi bien dans l'acquisition de l'activité enzymatique que dans la sécrétion de la rénine, mais fonctionne différemment d'un type cellulaire à l'autre. Nous avons montré pour la première fois que la prorégion interagit de façon intermoléculaire à l'intérieur de la cellule. Les expériences de complémentation montre que l'interaction favorable de la rénine avec la prorégion dépend de la taille de cette dernière : prorénine (383 acides aminés) > pro62 (62 acides aminés) > pro43 (43 acides aminés). Par ailleurs nos résultats montrent qu'une faible partie de la rénine est dirigée vers la voie de sécrétion régulée classique tandis que la majorité est dirigée vers les lysosomes. Ceci suggère qu'une internalisation de la rénine circulante via le récepteur mannose-6-phosphate est possible. Cette dernière concernerait essentiellement la prorénine (dont les taux circulants sont 10 fois plus élevés que la rénine active). La suite de ce travail porterait sur la confirmation de cette hypothèse et l'identification de son possible rôle physiologique. SUMMARY The renin-angiotensin system is critical for the control of blood pressure and salt balance and other physiological and pathological processes. When blood pressure is too low, renin is secreted by the juxtaglomerular cells. It will cleave the N-terminus of circulating angiotensinogen (mostly secreted by the liver) to angiotensin-1, which is then transformed in angiotensin-II by the angiotensin-converting-enzyme (ACE). This system is regulated at the level of renin release. Renin, an aspartyl protease, is produced from a larger precursor (called prorenin) which is matured into active renin. Although the role of the renin proregion remains unknown, it has been reported that it could act as an autoinhibitor. Works on other proteolytic enzymes showed that their prorégion can act as chaperones. prorenin is the major circulating form of renin, while active renin represents only 10%. The enzyme which transforms, in vivo, the prorenin into active renin is unknown and the exact cleavage site remains to be elucidated. In this study, we generated some prorenin mutants, which were expressed in CV1 cells (constitutive pathway model) or AtT-20 cells (regulated pathway model). We showed that the proregion plays a pivotal role in the enzymatic activity and secretion of renin in a different manner in the two cell types. For the first time, it has been demonstrated that the proregion acts in an intermolecular way into the cell. Complementation assays showed that interaction between renin and proregion depends on the size of the proregion: prorenin (383 amino acids) > pro62 (62 amino acids) > pro43 (43 amino acids). Furthermore, our results showed that only a small amount of the cellular renin pool is targeted to the "canonical" regulated pathway and that the remaining is targeted to the lysosomes. Those results suggest a possible internalizátion of the circulating renin through the mannose-6-phosphate receptor pathway. This would mostly concern the prorenin (whose levels are ten times higher than active renin). Further studies would confirm or infirm this hypothesis and elucidate a potential physiological role.

The JNK binding domain of islet-brain 1 inhibits IL-1 induced JNK activity and apoptosis but not the transcription of key proapoptotic or protective genes in insulin-secreting cell lines.

The stress-activated protein kinase c-Jun NH2-terminal kinase (JNK) is a central signal for interleukin-1beta (IL-1beta)-induced apoptosis in insulin-producing beta-cells. The cell-permeable peptide inhibitor of JNK (JNKI1), that introduces the JNK binding domain (JBD) of the scaffold protein islet-brain 1 (IB1) inside cells, effectively prevents beta-cell death caused by this cytokine. To define the molecular targets of JNK involved in cytokine-induced beta-cell apoptosis we investigated whether JNKI1 or stable expression of JBD affected the expression of selected pro- and anti-apoptotic genes induced in rat (RIN-5AH-T2B) and mouse (betaTC3) insulinoma cells exposed to IL-1beta. Inhibition of JNK significantly reduced phosphorylation of the specific JNK substrate c-Jun (p<0.05), IL-1beta-induced apoptosis (p<0.001), and IL-1beta-mediated c-fos gene expression. However, neither JNKI1 nor JBD did influence IL-1beta-induced NO synthesis or iNOS expression or the transcription of the genes encoding mitochondrial manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase rho (GSTrho), heat shock protein (HSP) 70, IL-1beta-converting enzyme (ICE), caspase-3, apoptosis-inducing factor (AIF), Bcl-2 or Bcl-xL. We suggest that the anti-apoptotic effect of JNK inhibition by JBD is independent of the transcription of major pro- and anti-apoptotic genes, but may be exerted at the translational or posttranslational level.

Peroxisomal and microsomal lipid pathways associated with resistance to hepatic steatosis and reduced pro-inflammatory state.

Accumulation of fat in the liver increases the risk to develop fibrosis and cirrhosis and is associated with development of the metabolic syndrome. Here, to identify genes or gene pathways that may underlie the genetic susceptibility to fat accumulation in liver, we studied A/J and C57Bl/6 mice that are resistant and sensitive to diet-induced hepatosteatosis and obesity, respectively. We performed comparative transcriptomic and lipidomic analysis of the livers of both strains of mice fed a high fat diet for 2, 10, and 30 days. We found that resistance to steatosis in A/J mice was associated with the following: (i) a coordinated up-regulation of 10 genes controlling peroxisome biogenesis and β-oxidation; (ii) an increased expression of the elongase Elovl5 and desaturases Fads1 and Fads2. In agreement with these observations, peroxisomal β-oxidation was increased in livers of A/J mice, and lipidomic analysis showed increased concentrations of long chain fatty acid-containing triglycerides, arachidonic acid-containing lysophosphatidylcholine, and 2-arachidonylglycerol, a cannabinoid receptor agonist. We found that the anti-inflammatory CB2 receptor was the main hepatic cannabinoid receptor, which was highly expressed in Kupffer cells. We further found that A/J mice had a lower pro-inflammatory state as determined by lower plasma levels and IL-1β and granulocyte-CSF and reduced hepatic expression of their mRNAs, which were found only in Kupffer cells. This suggests that increased 2-arachidonylglycerol production may limit Kupffer cell activity. Collectively, our data suggest that genetic variations in the expression of peroxisomal β-oxidation genes and of genes controlling the production of an anti-inflammatory lipid may underlie the differential susceptibility to diet-induced hepatic steatosis and pro-inflammatory state.

A-kinase anchoring protein-Lbc promotes pro-fibrotic signaling in cardiac fibroblasts

In response to stress or injury the heart undergoes an adverse remodeling process associated with cardiomyocyte hypertrophy and fibrosis. Transformation of cardiac fibroblasts to myofibroblasts is a crucial event initiating the fibrotic process. Cardiac myofibroblasts invade the myocardium and secrete excess amounts of extracellular matrix proteins, which cause myocardial stiffening, cardiac dysfunctions and progression to heart failure. While several studies indicate that the small GTPase RhoA can promote profibrotic responses, the exchange factors that modulate its activity in cardiac fibroblasts are yet to be identified. In the present study, we show that AKAP-Lbc, an A-kinase anchoring protein (AKAP) with an intrinsic Rho-specific guanine nucleotide exchange factor (GEF) activity, is critical for activating RhoA and transducing profibrotic signals downstream of type I angiotensin II receptors (AT1Rs) in cardiac fibroblasts. In particular, our results indicate that suppression of AKAP-Lbc expression by infecting adult rat ventricular fibroblasts with lentiviruses encoding AKAP-Lbc specific short hairpin (sh) RNAs strongly reduces the ability of angiotensin II to promote RhoA activation, differentiation of cardiac fibroblasts to myofibroblasts, collagen deposition as well as myofibroblast migration. Interestingly, AT1Rs promote AKAP-Lbc activation via a pathway that requires the α subunit of the heterotrimeric G protein G12. These findings identify AKAP-Lbc as a key Rho-guanine nucleotide exchange factor modulating profibrotic responses in cardiac fibroblasts.

Connexin36 contributes to INS-1E cells survival through modulation of cytokine-induced oxidative stress, ER stress and AMPK activity.

Cell-to-cell communication mediated by gap junctions made of Connexin36 (Cx36) contributes to pancreatic β-cell function. We have recently demonstrated that Cx36 also supports β-cell survival by a still unclear mechanism. Using specific Cx36 siRNAs or adenoviral vectors, we now show that Cx36 downregulation promotes apoptosis in INS-1E cells exposed to the pro-inflammatory cytokines (IL-1β, TNF-α and IFN-γ) involved at the onset of type 1 diabetes, whereas Cx36 overexpression protects against this effect. Cx36 overexpression also protects INS-1E cells against endoplasmic reticulum (ER) stress-mediated apoptosis, and alleviates the cytokine-induced production of reactive oxygen species, the depletion of the ER Ca(2+) stores, the CHOP overexpression and the degradation of the anti-apoptotic protein Bcl-2 and Mcl-1. We further show that cytokines activate the AMP-dependent protein kinase (AMPK) in a NO-dependent and ER-stress-dependent manner and that AMPK inhibits Cx36 expression. Altogether, the data suggest that Cx36 is involved in Ca(2+) homeostasis within the ER and that Cx36 expression is downregulated following ER stress and subsequent AMPK activation. As a result, cytokine-induced Cx36 downregulation elicits a positive feedback loop that amplifies ER stress and AMPK activation, leading to further Cx36 downregulation. The data reveal that Cx36 plays a central role in the oxidative stress and ER stress induced by cytokines and the subsequent regulation of AMPK activity, which in turn controls Cx36 expression and mitochondria-dependent apoptosis of insulin-producing cells.

Development of the first disease activity index for eosinophilic esophagitis: update on the EEsAI in 2012

Background and Aims: The international E EsAI s tudy g roup is currently d eveloping the first activity index ( EEsAI) specific for E osinophilic Esophagitis (EoE). G oal: T o develop, e valuate and validate the EEsAI. Methods: T he development c omprises three p hases: 1. Selection of c andidate items ( completed); 2. Evaluation of t he activity index i n a first patient cohort (in progress, p atient recruitment completed); and 3. Validation in a s econd EoE patient cohort. F ocus group interviews with patients were used in p hase 1 to g enerate patient r eported outcomes (PRO) according to g uidelines o f regulatory authorities (FDA a nd EMA), whereas the section of biologic items was developed by Delphi rounds o f international E oE experts from E urope and North America. Results: T he EEsAI has a modular c omposition to a ssess the following components o f EoE activity: p atient r eported outcomes, e ndoscopic activity, histologic activity, laboratory activity, a nd quality of l ife (QoL). Definitions for a ll aspects o f endoscopic and histologic appearance were e stablished by consensus r ounds a mong E oE experts. S ymptom a ssessment tools were c reated that t ake into account d ifferent food consistencies as w ell as f ood avoidance and specific processing strategies. The EEsAI i s currently e valuated in a cohort of a dult EoE patients since M arch 2 011 (patient recruitment completed). Conclusions: The EEsAI standardizes outcome assessment in EoE t rials. T he collaboration with i nternational E oE e xperts a s well as f ollowing o f the guidelines f rom regulatory authorities will lead to its wide applicability.

The Renin prosequence enhances constitutive secretion of Renin and optimizes Renin activity.

Renin is cleaved from its precursor prorenin into mature renin. We investigated the impact of the renin proregion on the generation and secretion of enzymatically active renin. We compared the effects of the following sequences of human prorenin with those of wild type prorenin[1-383]: prosequence [1-43], hinge sequence [1-62], Des[1-43]prorenin ("renin"), Des[1-62]prorenin and prorenin[N260]. These sequences were individually expressed in CV1 cells (constitutive pathway model) and AtT20 cells (regulated and constitutive pathways model), and Des[1-43]prorenin was also coexpressed together with the different prosequences. Renin concentration and activity were measured in cell extracts and culture media. Deletion of the prosequence reduces renin activity in both cell types, but it leaves (total) renin concentration unchanged. Coexpression of the prosequence with renin enhances renin secretion in both cell types: Constitutively secreted renin is enhanced by coexpression of renin together with any of the prosequence containing molecules [1-43], [1-62] or prorenin[N260]. Immunofluorescence in AtT20 cells shows lysosomal typical labeling of prorenin and Des[1-43]prorenin. In AtT20 cells expressing prorenin[1-383], stimulation of regulated secretion increases prorenin but not renin release. The renin prosequence [1-43] optimizes renin activity possibly through appropriate protein folding and it enhances the constitutive secretion of (pro)renin. The major part of generated renin may be targeted to lysosomes.

Work motivation and pro-social behavior in the delivery of public services : theoretical and empirical insights

This Ph.D. dissertation seeks to study the work motivation of employees in the delivery of public services. The questioning on work motivation in public services in not new but it becomes central for governments which are now facing unprecedented public debts. The objective of this research is twofold : First, we want to see if the work motivation of employees in public services is a continuum (intrinsic and extrinsic motivations cannot coexist) or a bi-dimensional construct (intrinsic and extrinsic motivations coexist simultaneously). The research in public administration literature has focused on the concept of public service motivation, and considered motivation to be uni-dimensional (Perry and Hondeghem 2008). However, no study has yet tackled both types of motivation, the intrinsic and extrinsic ones, in the same time. This dissertation proposes, in Part I, a theoretical assessment and an empirical test of a global work motivational structure, by using a self-constructed Swiss dataset with employees from three public services, the education sector, the security sector and the public administrative services sector. Our findings suggest that work motivation in public services in not uni-dimensional but bi-dimensional, the intrinsic and extrinsic motivations coexist simultaneously and can be positively correlated (Amabile et al. 1994). Our findings show that intrinsic motivation is as important as extrinsic motivation, thus, the assumption that employees in public services are less attracted by extrinsic rewards is not confirmed for this sample. Other important finding concerns the public service motivation concept, which, as theoretically predicted, represents the major motivational dimension of employees in the delivery of public services. Second, the theory of public service motivation makes the assumption that employees in public services engage in activities that go beyond their self-interest, but never uses this construct as a determinant for their pro-social behavior. In the same time, several studies (Gregg et al. 2011 and Georgellis et al. 2011) bring evidence about the pro-social behavior of employees in public services. However, they do not identify which type of motivation is at the origin of this behavior, they only make the assumption of an intrinsically motivated behavior. We analyze the pro-social behavior of employees in public services and use the public service motivation as determinant of their pro-social behavior. We add other determinants highlighted by the theory of pro-social behavior (Bénabou and Tirole 2006), by Le Grand (2003) and by fit theories (Besley and Ghatak 2005). We test these determinants on Part II and identify for each sector of activity the positive or the negative impact on pro-social behavior of Swiss employees. Contrary to expectations, we find, for this sample, that both intrinsic and extrinsic factors have a positive impact on pro-social behavior, no crowding-out effect is identified in this sample. We confirm the hypothesis of Le Grand (2003) about the positive impact of the opportunity cost on pro-social behavior. Our results suggest a mix of action-oriented altruism and out-put oriented altruism of employees in public services. These results are relevant when designing incentives schemes for employees in the delivery of public services.

Activation of peroxisome proliferator-activated receptor beta/delta inhibits lipopolysaccharide-induced cytokine production in adipocytes by lowering nuclear factor-kappaB activity via extracellular signal-related kinase 1/2.

OBJECTIVE: Chronic activation of the nuclear factor-kappaB (NF-kappaB) in white adipose tissue leads to increased production of pro-inflammatory cytokines, which are involved in the development of insulin resistance. It is presently unknown whether peroxisome proliferator-activated receptor (PPAR) beta/delta activation prevents inflammation in adipocytes. RESEARCH DESIGN AND METHODS AND RESULTS: First, we examined whether the PPARbeta/delta agonist GW501516 prevents lipopolysaccharide (LPS)-induced cytokine production in differentiated 3T3-L1 adipocytes. Treatment with GW501516 blocked LPS-induced IL-6 expression and secretion by adipocytes and the subsequent activation of the signal transducer and activator of transcription 3 (STAT3)-Suppressor of cytokine signaling 3 (SOCS3) pathway. This effect was associated with the capacity of GW501516 to impede LPS-induced NF-kappaB activation. Second, in in vivo studies, white adipose tissue from Zucker diabetic fatty (ZDF) rats, compared with that of lean rats, showed reduced PPARbeta/delta expression and PPAR DNA-binding activity, which was accompanied by enhanced IL-6 expression and NF-kappaB DNA-binding activity. Furthermore, IL-6 expression and NF-kappaB DNA-binding activity was higher in white adipose tissue from PPARbeta/delta-null mice than in wild-type mice. Because mitogen-activated protein kinase-extracellular signal-related kinase (ERK)1/2 (MEK1/2) is involved in LPS-induced NF-kappaB activation in adipocytes, we explored whether PPARbeta/delta prevented NF-kappaB activation by inhibiting this pathway. Interestingly, GW501516 prevented ERK1/2 phosphorylation by LPS. Furthermore, white adipose tissue from animal showing constitutively increased NF-kappaB activity, such as ZDF rats and PPARbeta/delta-null mice, also showed enhanced phospho-ERK1/2 levels. CONCLUSIONS: These findings indicate that activation of PPARbeta/delta inhibits enhanced cytokine production in adipocytes by preventing NF-kappaB activation via ERK1/2, an effect that may help prevent insulin resistance.

Development and validation of a symptom-based activity index for adults with eosinophilic esophagitis.

BACKGROUND & AIMS: Standardized instruments are needed to assess the activity of eosinophilic esophagitis (EoE) and to provide end points for clinical trials and observational studies. We aimed to develop and validate a patient-reported outcome (PRO) instrument and score, based on items that could account for variations in patient assessments of disease severity. We also evaluated relationships between patient assessment of disease severity and EoE-associated endoscopic, histologic, and laboratory findings. METHODS: We collected information from 186 patients with EoE in Switzerland and the United States (69.4% male; median age, 43 y) via surveys (n = 135), focus groups (n = 27), and semistructured interviews (n = 24). Items were generated for the instruments to assess biologic activity based on physician input. Linear regression was used to quantify the extent to which variations in patient-reported disease characteristics could account for variations in patient assessment of EoE severity. The PRO instrument was used prospectively in 153 adult patients with EoE (72.5% male; median age, 38 y), and validated in an independent group of 120 patients with EoE (60.8% male; median age, 40.5 y). RESULTS: Seven PRO factors that are used to assess characteristics of dysphagia, behavioral adaptations to living with dysphagia, and pain while swallowing accounted for 67% of the variation in patient assessment of disease severity. Based on statistical consideration and patient input, a 7-day recall period was selected. Highly active EoE, based on endoscopic and histologic findings, was associated with an increase in patient-assessed disease severity. In the validation study, the mean difference between patient assessment of EoE severity (range, 0-10) and PRO score (range, 0-8.52) was 0.15. CONCLUSIONS: We developed and validated an EoE scoring system based on 7 PRO items that assess symptoms over a 7-day recall period. Clinicaltrials.gov number: NCT00939263.

Plasma lipoprotein-associated phospholipase A2 activity in Alzheimer's disease, amnestic mild cognitive impairment, and cognitively healthy elderly subjects: a cross-sectional study.

ABSTRACT: INTRODUCTION: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a circulating enzyme with pro-inflammatory and oxidative activities associated with cardiovascular disease and ischemic stroke. While high plasma Lp-PLA2 activity was reported as a risk factor for dementia in the Rotterdam study, no association between Lp-PLA2 mass and dementia or Alzheimer's disease (AD) was detected in the Framingham study. The objectives of the current study were to explore the relationship of plasma Lp-PLA2 activity with cognitive diagnoses (AD, amnestic mild cognitive impairment (aMCI), and cognitively healthy subjects), cardiovascular markers, cerebrospinal fluid (CSF) markers of AD, and apolipoprotein E (APOE) genotype. METHODS: Subjects with mild AD (n = 78) and aMCI (n = 59) were recruited from the Memory Clinic, University Hospital, Basel, Switzerland; cognitively healthy subjects (n = 66) were recruited from the community. Subjects underwent standardised medical, neurological, neuropsychological, imaging, genetic, blood and CSF evaluation. Differences in Lp-PLA2 activity between the cognitive diagnosis groups were tested with ANOVA and in multiple linear regression models with adjustment for covariates. Associations between Lp-PLA2 and markers of cardiovascular disease and AD were explored with Spearman's correlation coefficients. RESULTS: There was no significant difference in plasma Lp-PLA2 activity between AD (197.1 (standard deviation, SD 38.4) nmol/min/ml) and controls (195.4 (SD 41.9)). Gender, statin use and low-density lipoprotein cholesterol (LDL) were independently associated with Lp-PLA2 activity in multiple regression models. Lp-PLA2 activity was correlated with LDL and inversely correlated with high-density lipoprotein (HDL). AD subjects with APOE-ε4 had higher Lp-PLA2 activity (207.9 (SD 41.2)) than AD subjects lacking APOE-ε4 (181.6 (SD 26.0), P = 0.003) although this was attenuated by adjustment for LDL (P = 0.09). No strong correlations were detected for Lp-PLA2 activity and CSF markers of AD. CONCLUSION: Plasma Lp-PLA2 was not associated with a diagnosis of AD or aMCI in this cross-sectional study. The main clinical correlates of Lp-PLA2 activity in AD, aMCI and cognitively healthy subjects were variables associated with lipid metabolism.

Pharmacological inhibition of nicotinamide phosphoribosyltransferase/visfatin enzymatic activity identifies a new inflammatory pathway linked to NAD.

Nicotinamide phosphoribosyltransferase (NAMPT), also known as visfatin, is the rate-limiting enzyme in the salvage pathway of NAD biosynthesis from nicotinamide. Since its expression is upregulated during inflammation, NAMPT represents a novel clinical biomarker in acute lung injury, rheumatoid arthritis, and Crohn's disease. However, its role in disease progression remains unknown. We report here that NAMPT is a key player in inflammatory arthritis. Increased expression of NAMPT was confirmed in mice with collagen-induced arthritis, both in serum and in the arthritic paw. Importantly, a specific competitive inhibitor of NAMPT effectively reduced arthritis severity with comparable activity to etanercept, and decreased pro-inflammatory cytokine secretion in affected joints. Moreover, NAMPT inhibition reduced intracellular NAD concentration in inflammatory cells and circulating TNFalpha levels during endotoxemia in mice. In vitro pharmacological inhibition of NAMPT reduced the intracellular concentration of NAD and pro-inflammatory cytokine secretion by inflammatory cells. Thus, NAMPT links NAD metabolism to inflammatory cytokine secretion by leukocytes, and its inhibition might therefore have therapeutic efficacy in immune-mediated inflammatory disorders.