The effects of pre–B-cell colony–enhancing factor on the human fetal membranes by microarray analysis

Involvement of Novel Adipokines, Chemerin, Visfatin, Resistin and Apelin in Reproductive Functions in Normal and Pathological Conditions in Humans and Animal Models

It is well known that adipokines are endocrine factors that are mainly secreted by white adipose tissue. Their central role in energy metabolism is currently accepted. More recently, their involvement in fertility regulation and the development of some reproductive disorders has been suggested. Data concerning the role of leptin and adiponectin, the two most studied adipokines, in the control of the reproductive axis are consistent. In recent years, interest has grown about some novel adipokines, chemerin, visfatin, resistin and apelin, which have been found to be strongly associated with obesity and insulin-resistance. Here, we will review their expression and role in male and female reproduction in humans and animal models. According to accumulating evidence, they could regulate the secretion of GnRH (Gonadotropin-Releasing Hormone), gonadotropins and steroids. Furthermore, their expression and that of their receptors (if known), has been demonstrated in the human and animal hypothalamo-pituitary-gonadal axis. Like leptin and adiponectin, these novel adipokines could thus represent metabolic sensors that are able to regulate reproductive functions according to energy balance changes. Therefore, after investigating their role in normal fertility, we will also discuss their possible involvement in some reproductive troubles known to be associated with features of metabolic syndrome, such as polycystic ovary syndrome, gestational diabetes mellitus, preeclampsia and intra-uterine growth retardation in women, and sperm abnormalities and testicular pathologies in men.

Gestational tissue inflammatory biomarkers at term labor: A systematic review of literature

Parturition at term is characterized by inflammatory overload in both feto-maternal tissues. Despite the large number of individual studies on changes in inflammatory biomarkers linked to labor, a comprehensive profile of them in each of the uterine compartments is not available to better understand their mechanistic contributions to labor. This systematic review investigated the pro- and anti-inflammatory biomarkers reported in intra-uterine tissues (amnion, chorion, decidua, placenta, and myometrium) at term labor. We conducted a systematic review of studies on pro- and anti-inflammatory biomarkers (mRNA and/or protein) reported in feto-maternal tissues during normal human term labor, published in English (1980-2016), in 3 electronic data bases. From a total of 3712 citations, 172 were included for final review. Each tissue expresses a unique set of biomarkers at the time of term labor, but there is significant overlap between tissues. All tissues had IL-6, IL-8, IL-1β, COX-2, PGE-2, TNF-α, and hCAP18 in common at term labor. Common and unique inflammatory biomarkers are expressed in various feto-maternal compartments at term labor. Increase in pro-inflammatory markers in all gestational tissue signifies their harmonious functional role in promoting labor. Anti-inflammatory markers at term labor are hardly reported.

Aberrant Expression of TIMP-2 and PBEF Genes in the Placentae of Cloned Mice Due to Epigenetic Reprogramming Error

Cloned mice derived from somatic or ES cells show placental overgrowth (placentomegaly) at term. We had previously analyzed cloned and normal mouse placentae by using two-dimensional gel electrophoresis and mass spectrometry to identify differential protein expression patterns. Cloned placentae showed upregulation of tissue inhibitor of metalloproteinase-2 (TIMP-2), which is involved in extracellular matrix degradation and tissue remodeling, and downregulation of pre-B cell colony enhancing factor 1 (PBEF), which inhibits apoptosis and induces spontaneous labor. Here, we used Western blotting to further analyze the protein expression levels of TIMP-2 and PBEF in cloned placentae derived from cumulus cells, TSA-treated cumulus cells, intracytoplasmic sperm injection (ICSI), and natural mating (NM control). Cloned and TSA-treated cloned placentae had higher expression levels of TIMP-2 compared with NM control and ICSI-derived placentae, and there was a positive association between TIMP-2 expression and the placental weight of cloned mouse concepti. Conversely, PBEF protein expression was significantly lower in cloned and ICSI placentae compared to NM controls. To examine whether the observed differences were due to abnormal gene expression caused by faulty epigenetic reprogramming in clones, we investigated DNA methylation and histone modification in the promoter regions of the genes encoding TIMP-2 and PBEF. Sodium bisulfite sequencing did not reveal any difference in DNA methylation between cloned and NM control placentae. However, ChIP assays revealed that the level of H3-K9/K14 acetylation at the TIMP-2 locus was higher in cloned placentae than in NM controls, whereas acetylation of the PBEF promoter was lower in cloned and ICSI placenta versus NM controls. These results suggest that cloned placentae appear to suffer from failure of histone modification-based reprogramming in these (and potentially other) developmentally important genes, leading to aberrant expression of their protein products. These changes are likely to be involved in generating the abnormalities seen in cloned mouse placentae, including enlargement and/or a lack of proper placental function.

Visfatin/Nampt and SIRT1: Roles in Postterm Delivery in Pregnancies Associated With Obesity

Visfatin is both a systemic adipocytokine and the cytosolic enzyme, nicotinamide phosphoribosyl transferase (Nampt). This is a longevity protein, which extends the lifespan of human cells by activating sirtuin 1 (SIRT1). In this study, we sought a role for these proteins in obese pregnant women, who experience more postterm deliveries. Thus, 78 women (26 lean, 24 overweight, and 28 obese) were recruited and maternal blood and placental tissue collected prior to term labor. Plasma levels were measured by enzyme-linked immunosorbent assay and quantitative immunohistochemistry used for placenta. We confirmed maternal plasma interleukin 6 increased according to prepregnancy body mass index (BMI; P < .0001) and showed a linear relationship between BMI and syncytiotrophoblast visfatin/Nampt (P = .021) but not with its levels in maternal plasma. Both systemic and placental visfatin/Nampt were significantly associated with placental SIRT1 levels (P = .028 and .017). Thus, higher visfatin/Nampt may prevent a labor-associated decrease in SIRT1 leading to postterm delivery in obesity.

Elevated plasma visfatin levels correlate with conversion of laparoscopic cholecystectomy to open surgery in acute cholecystitis

Visfatin correlates with inflammation and its levels in peripheral blood are associated with some inflammatory diseases. This study aimed to assess the relationship between plasma visfatin levels and conversion of laparoscopic cholecystectomy to open surgery in acute cholecystitis. One hundred and forty-six acute cholecystitis patients and 146 sex- and age-matched healthy controls were recruited and their plasma visfatin levels were determined using an enzyme immunoassay. 17 patients (11.6%) underwent conversion. Plasma visfatin levels were statistically significantly elevated in all patients (97.2±41.8ng/mL), those with (161.4±71.3ng/mL) or without conversion (88.7±26.9ng/mL), compared to controls (40.3±13.3ng/mL, all P<0.001). A linear regression analysis showed that plasma visfatin levels were positively associated with plasma C-reactive protein levels (t=0.510, P<0.001). A logistic-regression analysis showed that age [odds ratio (OR) 1.160, 95% confidence interval (CI) 1.011-1.332, P=0.035] and plasma visfatin levels (OR 1.035, 95% CI 1.005-1.066, P=0.022) appeared to be the independent predictors of conversion. A receiver operating characteristic curve analysis found that plasma visfatin levels predicted conversion with high area under curve (AUC) (AUC, 850; 95% CI, 0.781-0.903). The AUC of the visfatin concentration was similar to that of age (AUC, 0.738; 95% CI, 0.659-0.807) (P=0.188). Visfatin improved the AUC of age to 0.914 (95% CI, 0.856-0.954) (P=0.011) using a combined logistic-regression model. Thus, high plasma levels of visfatin are associated with systemic inflammation, and may independently predict conversion of laparoscopic cholecystectomy to open surgery in acute cholecystitis.

Elevated plasma visfatin levels correlate with poor prognosis of gastric cancer patients

Visfatin is a proinflammmatory cytokine with accumulating evidence for its rise in circulation of cancer patients. This study aimed to evaluate the relationship between preoperative plasma visfatin level and prognosis of gastric cancers. Preoperative plasma visfatin levels of 262 patients with gastric cancers and plasma visfatin levels of 262 healthy individuals were determined using enzyme-linked immunosorbent assay. Preoperative plasma visfatin level was substantially higher in patients than in healthy subjects. Plasma visfatin levels were associated with invasion depth, lymph node metastasis, distant metastasis, peritoneal dissemination, tumor size and tumor node metastasis stage. Multivariate analysis revealed that high plasma visfatin level was an independent factor for death. Receiver operating characteristic curve analysis showed that plasma visfatin level predicted death with high area under curve. Multivariate Cox regression analysis identified plasma visfatin level as an independent predictor of overall survival. Thus, our results suggest that high preoperative plasma visfatin level is associated with prognostic factors for gastric cancer as well as may play a role as prognostic biomarker in gastric cancer survival.

Adipokines in gestational diabetes

Gestational diabetes is characterised by glucose intolerance with onset or first recognition during pregnancy. The disease shows facets of the metabolic syndrome including obesity, insulin resistance, and dyslipidaemia. Adipokines are a group of proteins secreted from adipocytes, which are dysregulated in obesity and contribute to metabolic and vascular complications. Recent studies have assessed the role of various adipokines including leptin, adiponectin, tumour necrosis factor α (TNFα), adipocyte fatty acid-binding protein (AFABP), retinol-binding protein 4 (RBP4), resistin, NAMPT, SERPINA12, chemerin, progranulin, FGF-21, TIMP1, LCN2, AZGP1, apelin (APLN), and omentin in gestational diabetes. This Review provides an overview of these key adipokines, their regulation in, and potential contribution to gestational diabetes. Based on the evidence so far, the adipokines adiponectin, leptin, TNFα, and AFABP seem to be the most probable candidates involved in the pathophysiology of gestational diabetes.

Immunomodulatory effects of sex hormones: requirements for pregnancy and relevance in melanoma

Similarities between the pathologic progression of cancer and the physiologic process of placentation (eg, proliferation, invasion, and local/systemic tolerance) have been recognized for many years. Sex hormones such as human chorionic gonadotropin, estrogens, progesterone, and others contribute to induction of immunologic tolerance at the beginning of gestation. Sex hormones have been shown to play contributory roles in the growth of cancers such as breast cancer, prostrate cancer, endometrial cancer, and ovarian cancer, but their involvement as putative mediators of the immunologic escape of cancer is still being elucidated. Herein, we compare the emerging mechanism by which sex hormones modulate systemic immunity in pregnancy and their potentially similar role in cancer. To do this, we conducted a PubMed search using combinations of the following keywords: "immune regulation," "sex hormones," "pregnancy," "melanoma," and "cancer." We did not limit our search to specific publication dates. Mimicking the maternal immune response to pregnancy, especially in late gestation, might aid in design of better therapies to reconstitute endogenous antitumor immunity and improve survival.

Pre-B cell colony enhancing factor (PBEF), a cytokine with multiple physiological functions

Pre-B cell colony enhancing factor (PBEF) is regarded as a proinflammatory cytokine. Named for its first discovered function as a pre-B cell colony enhancing factor, it has since been found to have many other functions relating to cell metabolism, inflammation, and immune modulation. It has also been found to have intracellular and extracellular forms, with the two overlapping in function. Most of the intracellular functions of PBEF are due to its role as a nicotinamide phosphoribosyltransferase (Nampt). It has been found in human endothelial cells, where it is able to induce angiogenesis through upregulation of VEGF and VEGFR and secretion of MCP-1. In human umbilical endothelial cells, PBEF increases levels of the protease MMP 2/9. PBEF has also been found in a variety of immune cells other than B cells and has been shown to inhibit apoptosis of macrophages. Extracellular PBEF has been shown to increase inflammatory cytokines, such as TNF-α, IL-1β, IL-16, and TGF-β1, and the chemokine receptor CCR3. PBEF also increases the production of IL-6, TNF-α, and IL-1β in CD14(+) monocyctes, macrophages, and dendritic cells, enhances the effectiveness of T cells, and is vital to the development of both B and T lymphocytes. The purpose of this review is to summarize the recent advances in PBEF research.

Potential mechanisms of exercise in gestational diabetes

Gestational diabetes mellitus (GDM) is defined as glucose intolerance first diagnosed during pregnancy. This condition shares same array of underlying abnormalities as occurs in diabetes outside of pregnancy, for example, genetic and environmental causes. However, the role of a sedentary lifestyle and/or excess energy intake is more prominent in GDM. Physically active women are less likely to develop GDM and other pregnancy-related diseases. Weight gain in pregnancy causes increased release of adipokines from adipose tissue; many adipokines increase oxidative stress and insulin resistance. Increased intramyocellular lipids also increase cellular oxidative stress with subsequent generation of reactive oxygen species. A well-planned program of exercise is an important component of a healthy lifestyle and, in spite of old myths, is also recommended during pregnancy. This paper briefly reviews the role of adipokines in gestational diabetes and attempts to shed some light on the mechanisms by which exercise can be beneficial as an adjuvant therapy in GDM. In this regard, we discuss the mechanisms by which exercise increases insulin sensitivity, changes adipokine profile levels, and boosts antioxidant mechanisms.

Plasma visfatin, associated with a genetic polymorphism -1535C>T, is correlated with C-reactive protein in Chinese Han patients with traumatic brain injury

Visfatin is a newly identified pro-inflammatory adipokine and a genetic polymorphism -1535 C>T located in the visfatin gene promoter has been suggested to be associated with the regulation of visfatin expression in some inflammatory illness. However, there were some conflicting results regarding whether this variant is functional or not. This study aimed to examine the relations of the -1535 C>T single nucleotide polymorphism (SNP) of visfatin gene to the plasma visfatin and C-reactive protein concentrations in traumatic brain injury (TBI). 318 Chinese Han patients with TBI were recruited in this study. Plasma visfatin and C-reactive protein levels were significantly different between the genotypes in the SNP-1535 C>T even after adjustment for age, sex and body mass index. The genotype C-C had the highest plasma visfatin and C-reactive protein concentrations. The plasma visfatin and C-reactive protein concentrations between the variant genotypes C-T and T-T did not differ significantly. Plasma visfatin level was significantly associated with plasma C-reactive protein level using multivariate linear regression. Thus, the SNP-1535 C>T of visfatin gene seemed to be potentially involved in the inflammatory component of TBI through a decreased production of visfatin.

High concentrations of visfatin in the peripheral blood of patients with acute basal ganglia hemorrhage are associated with poor outcome

Higher plasma visfatin concentration has been associated with clinical outcomes of traumatic brain injury. No published information exists to date about change in plasma visfatin after intracerebral hemorrhage. This study included one hundred and twenty-eight healthy controls and 128 patients with intracerebral hemorrhage. The unfavorable outcome was defined as modified Rankin Scale score >2 at 6 months. The patients had higher plasma visfatin measurements than control subjects. Plasma visfatin levels were highly correlated with National Institutes of Health Stroke Scale score and plasma C-reactive protein levels in the patients. A multivariate analysis identified plasma visfatin level as an independent predictor for 6-month mortality and unfavorable outcome. According to receiver operating characteristic curve analysis, the predictive value of the plasma visfatin concentration was similar to National Institutes of Health Stroke Scale score. In a combined logistic-regression model, visfatin improved the predictive value of National Institutes of Health Stroke Scale score for 6-month unfavorable outcome. Thus, increased plasma visfatin level is associated with 6-month clinical outcomes after intracerebral hemorrhage.

Change in plasma visfatin level after severe traumatic brain injury

Higher plasma visfatin concentration has been associated with ischemic stroke. Thus, we sought to investigate change in plasma visfatin level after traumatic brain injury and to evaluate its relation with disease outcome. Seventy-six healthy controls and 98 patients with acute severe traumatic brain injury were recruited. Twenty-seven patients (27.6%) died and 48 patients (49.0%) suffered from unfavorable outcome (Glasgow outcome scale score of 1-3) in 6 months. On admission, plasma visfatin level was increased in patients than in healthy controls and was highly correlated with Glasgow Coma Scale score. A multivariate analysis identified plasma visfatin level as an independent predictor for 6-month mortality and unfavorable outcome. According to receiver operating characteristic curve analysis, the predictive value of the plasma visfatin concentration was similar to Glasgow Coma Scale score's. In a combined logistic-regression model, visfatin did not improve the predictive value of Glasgow Coma Scale score. Thus, increased plasma visfatin level is associated with 6-month clinical outcomes after severe traumatic brain injury.

Leptin, adiponectin and other adipokines in gestational diabetes mellitus and pre-eclampsia

Proteins secreted from adipocytes - so-called adipokines - influence metabolic and vascular function. Recent data suggest that various adipokines are dysregulated in gestational diabetes mellitus (GDM) and pre-eclampsia (PE) and might be of pathophysiological and prognostic significance in these complications of pregnancy. This review gives an overview on the regulation and pathophysiology of leptin and adiponectin in GDM and PE. Furthermore, data on novel adipokines including resistin, visfatin, retinol-binding protein 4 and vaspin are summarized.

Epigenetic characterization of the PBEF and TIMP-2 genes in the developing placentae of normal mice

Reprogramming errors, which appear frequently in cloned animals, are reflected by aberrant gene expression. We previously reported the aberrant expression of TIMP-2 and PBEF in cloned placenta and differential expression of PBEF genes during pregnancy. To examine the epigenetic modifications that regulate dynamic gene expression in developing placentae, we herein analyzed the mRNA and protein expression levels of PBEF and TIMP-2 in the placentae of normal mice during pregnancy and then examined potential correlations with epigenetic modifications. DNA methylation pattern analysis revealed no difference, but ChIP assays using antibodies against H3-K9/K14 and H4-K5 histone acetylation revealed that the H3-K9/K14 acetylation levels, but not the H4-K5 acetylation levels, of the TIMP-2 and PBEF loci were significantly correlated with their gene expression levels during placentation in normal mice. These results suggest that epigenetic changes may regulate gene expression level in the developing placentae of normal mice and that inappropriate epigenetic reprogramming might be one cause of the abnormal placentae seen in cloned animals.

Maternal and neonatal circulating visfatin concentrations in patients with pre-eclampsia and a small-for-gestational age neonate

OBJECTIVE

Maternal circulating visfatin concentrations are higher in patients with a small-for-gestational-age (SGA) neonate than in those who delivered an appropriate-for-gestational age (AGA) neonate or in those with pre-eclampsia. It has been proposed that enhanced transfer of visfatin from the foetal to maternal circulation may account for the high concentrations of maternal visfatin observed in patients with an SGA neonate. The aims of this study were: (1) to determine whether cord blood visfatin concentrations differ between normal neonates, SGA neonates and newborns of pre-eclamptic mothers; and (2) to assess the relationship between maternal and foetal circulating visfatin concentrations in patients with an SGA neonate and those with pre-eclampsia.

STUDY DESIGN

This cross-sectional study included 88 pregnant women and their neonates, as well as 22 preterm neonates in the following groups: (1) 44 normal pregnant women at term and their AGA neonates; (2) 22 normotensive pregnant women and their SGA neonates; (3) 22 women with pre-eclampsia and their neonates; and (4) 22 preterm neonates delivered following spontaneous preterm labour without funisitis or histologic chorioamnionitis, matched for gestational age with infants of pre-eclamptic mothers. Maternal plasma and cord blood visfatin concentrations were determined by ELISA. Non-parametric statistics were used for analyses.

RESULTS

(1) The median visfatin concentration was lower in umbilical cord blood than in maternal circulation, in normal pregnancy, SGA and pre-eclampsia groups (p<0.001 for all comparisons); (2) the median cord blood visfatin concentrations did not differ significantly between term AGA or SGA neonates, infants of mothers with pre-eclampsia and their gestational-age-matched preterm AGA neonates; (3) maternal and cord blood visfatin concentrations correlated only in the normal term group (r=0.48, p=0.04).

CONCLUSION

Circulating visfatin concentrations are lower in the foetal than in the maternal circulation and did not significantly differ between the study groups. Thus, it is unlikely that the foetal circulation is the source of the high maternal visfatin concentrations reported in patients with an SGA neonate.

Could alterations in maternal plasma visfatin concentration participate in the phenotype definition of preeclampsia and SGA?

OBJECTIVE

Women with preeclampsia and those who delivered a small-for-gestational-age (SGA) neonate share several mechanisms of disease, including chronic uteroplacental ischemia and failure of physiologic transformation of the spiral arteries. However, the clinical manifestation of these obstetrical syndromes is remarkably different. It has been proposed that an altered maternal metabolic state, as well as a unique circulating cytokines milieu, predispose women to develop either preeclampsia or SGA. Compelling evidence suggests that adipose tissue orchestrates both metabolic pathways and immunological responses via the production of adipokines. Visfatin is a novel adipocytokine with metabolic and immunomodulating properties. The objective of this study was to determine whether preeclampsia and SGA are associated with alterations in maternal circulating visfatin concentrations.

METHODS

This cross-sectional study included pregnant women in the following groups: (1) normal pregnancy (n = 158); (2) patients with preeclampsia (n = 43) of which 32 had an AGA and 11 had an SGA neonate; (3) patients without preeclampsia who delivered an SGA neonate (n = 55). Maternal plasma visfatin concentrations were measured by ELISA. Nonparametric tests and multiple linear regression analysis were used.

RESULTS

(1) Women who delivered an SGA neonate had a higher median maternal plasma visfatin concentration than those with a normal pregnancy (20.0 ng/ml, interquartile range: 17.2-24.6 vs. 15.2 ng/ml, 12.1-19.2, respectively; P < 0.001) and than those with preeclampsia (14.5 ng/ml, 12.5-18.7; P < 0.001); (2) the median maternal plasma visfatin concentration did not differ significantly between patients with preeclampsia and those with a normal pregnancy (P = 0.8); (3) among patients with preeclampsia, there was no significant difference in the median maternal plasma visfatin concentration between those with or without an SGA neonate (P = 0.5); (4) in a linear regression model, delivery of an SGA neonate and pregestational body mass index were independently associated with increased visfatin concentration after adjustment for confounding factors (maternal age, smoking, gestational age at blood collection and the presence of preeclampsia or SGA).

CONCLUSION

(1) Patients with SGA, but not those with preeclampsia, had a higher maternal plasma visfatin concentration than those with a normal pregnancy; (2) this finding suggests differential involvement of visfatin in SGA and preeclampsia; (3) we propose that changes in circulating maternal visfatin concentration may be implicated in the phenotypic definitions and distinction of preeclampsia and SGA.

Stretch and inflammation-induced Pre-B cell colony-enhancing factor (PBEF/Visfatin) and Interleukin-8 in amniotic epithelial cells

Preterm birth continues to be a growing problem in the USA. Although approximately half of preterm births are caused by intrauterine infection, uterine over-distension is also a cause. In this study we have compared the effects of static stretch, cyclic stretch/release and an inflammatory stimulus alone and in combination on the expression of Pre-B cell colony-enhancing factor (PBEF) and IL-8 in primary amniotic epithelial cells (AEC). We then sought to identify some of the mechanism(s) by which these cells respond to stretching stimuli. We show that cyclic stretch/release is a more robust stimulus for both PBEF and IL-8 than static stretch. Cyclic stretch/release increased both intracellular and secreted PBEF and a combination of both types of stretch was a more robust stimulus to PBEF that IL-8. However, when an inflammatory stimulus (IL-1beta) was added to either kind of stretch, the effect on IL-8 was much greater than that on PBEF. Thus, different kinds of stretch affect the expression of these two cytokines from AEC, but inflammation is a much stronger stimulus of IL-8 than PBEF, agreeing with its primary role as a chemokine. Although the AEC showed morphological signs of increased cellular stress during stretching, blocking reactive oxygen species (ROS) had little effect. However, blocking integrin binding to fibronectin significantly reduced the responses of both PBEF and IL-8 to cyclic stretch/release. The increased PBEF, both intracellularly and secreted, suggests that it functions both to increase the metabolism of the cells, at the same time as stimulating further the cytokine cascade leading to parturition.

Lack of direct insulin-like action of visfatin/Nampt/PBEF1 in human adipocytes

Visfatin, a protein identified as a secretion product of visceral fat in humans and mice, is also expressed in different anatomical locations, and is known as pre-B cell-colony enhancing factor (PEBF1). It is also an enzyme displaying nicotinamide phosphoribosyltransferase activity (Nampt). The evidence that levels of visfatin correlate with visceral fat mass has been largely debated and widely extended to other regulations in numerous clinical studies and in diverse animal models. On the opposite, the initial findings regarding the capacity of visfatin/Nampt/PEBF1 to bind and to activate the insulin receptor have been scarcely reproduced, and even were contradicted in recent reports. Since the putative insulin mimicking effects of visfatin/Nampt/PEBF1 have never been tested on mature human adipocytes, at least to our knowledge, we tested different human visfatin batches on human fat cells freshly isolated from subcutaneous abdominal fat and exhibiting high insulin responsiveness. Up to 10 nM, visfatin was devoid of clear activatory action on glucose transport in human fat cells while, in the same conditions, insulin increased by more than threefold the basal 2-deoxyglucose uptake. Moreover, visfatin was unable to mimic the lipolysis inhibition induced by insulin. Visfatin definitively cannot be considered as a direct activator of insulin signalling in human fat cells. Nevertheless itsin vivo effects on insulin release and on glucose handling deserve to further study the role of this multifunctional extracellular enzyme in obese and diabetic states.

Evidence for differential regulation of the adipokine visfatin in the maternal and fetal compartments in normal spontaneous labor at term

OBJECTIVE

Visfatin, a novel adipokine with metabolic and immunoregulatory properties, has been implicated in the regulation of fetal growth, as well as in preterm labor. A gap in knowledge is whether spontaneous labor at term is associated with changes in the maternal and fetal concentrations of visfatin. The aim of this study was to determine if the presence of labor at term is associated with alterations in maternal and neonatal plasma visfatin concentrations.

STUDY DESIGN

This cross-sectional study included 50 normal pregnant women at term and their appropriate-for-gestational age (AGA) neonates in the following groups: 1) 25 mother-neonate pairs delivered by elective cesarean section without spontaneous labor, and 2) 25 mother-neonate pairs who delivered vaginally following spontaneous labor. Maternal plasma and cord blood visfatin concentrations were determined by ELISA. Non-parametric statistics were used for analyses.

RESULTS

1) The median visfatin concentration was higher in umbilical cord plasma of neonates born following a spontaneous labor at term than that of those who were born by an elective cesarean section (P=0.02); 2) in contrast, the median maternal plasma visfatin concentration did not differ significantly between patients with and without labor (P=0.44); and 3) there was a significant correlation between umbilical cord plasma concentration of visfatin and both maternal visfatin concentration (r=0.54, P=0.005) and gestational age (GA) at delivery (r=0.58; P=0.002) only in the absence of labor.

CONCLUSION

Term labor is associated with increased fetal, but not maternal, circulating visfatin concentrations. Previous reports indicate that preterm labor leading to preterm delivery is characterized by an increase in maternal plasma concentrations of visfatin. The observations reported herein support the view that there are fundamental differences in the endocrine and metabolic adaptations in normal labor at term and preterm labor.

Maternal plasma visfatin in preterm labor

OBJECTIVE

Visfatin, a novel adipokine with diabetogenic and immunoregulatory properties, has been implicated in the pathophysiology of insulin resistance, as well as in various acute and chronic inflammatory disorders. We have previously reported that amniotic fluid concentrations of visfatin are higher in patients with preterm labor (PTL) and intra-amniotic infection than in patients with PTL without infection. The aim of this study was to determine whether spontaneous PTL with intact membranes and intra-amniotic infection/inflammation (IAI) is associated with changes in maternal plasma circulating visfatin concentrations.

STUDY DESIGN

This cross-sectional study included patients in the following groups: (1) normal pregnant women (n = 123); (2) patients with an episode of PTL and intact membranes without IAI who delivered at term (n = 57); (3) PTL without IAI who delivered preterm (n = 47); and (4) PTL with IAI who delivered preterm (n = 57). Plasma visfatin concentrations were determined by ELISA. Non-parametric statistics were used for analysis.

RESULTS

(1) PTL with IAI leading to preterm delivery was associated with a higher median maternal plasma concentration of visfatin than normal pregnancy; (2) among patients with PTL, those with IAI had the highest median maternal concentration of visfatin; (3) the changes in maternal plasma visfatin remained significant after adjusting for maternal age, body mass index, gestational age at sampling, and birth weight.

CONCLUSION

(1) PTL with IAI is characterized by high maternal circulating visfatin concentrations; (2) these findings suggest that visfatin plays a role in the regulation of the metabolic adaptations to insults resulting in PTL in the context of IAI.

Visfatin in gestational diabetes: serum level and mRNA expression in fat and placental tissue

AIMS AND METHODS

In this study we measured: (1) serum visfatin concentrations in pregnant women with normal glucose tolerance (NGT) and gestational diabetes mellitus (GDM) between 26 and 33 weeks of gestation, using two immunoassays: EIA and ELISA; (2) serum visfatin levels (ELISA) and its mRNA expression (quantitative real-time PCR) in subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and placental tissue from women with NGT and GDM at term.

RESULTS

Visfatin concentrations (measured by EIA and ELISA) did not differ in the women with GDM and NGT between 26 and 33 weeks of gestation but were significantly lower in GDM than in NGT subjects at term (2.7 [0.7-4.6] vs 5.2 [3.7-5.9]ng/ml, p=0.02). There was no difference in visfatin mRNA expression in fat and placental tissue between the two subgroups. Regression analysis revealed that visfatin mRNA expression was significantly related to interleukin-6 and tumour necrosis factor-alpha mRNA expression in SAT (beta=0.39, p=0.009 and beta=0.47, p=0.002) and placental tissue (beta=0.37, p=0.03 and beta=0.49, p=0.005).

CONCLUSIONS

Circulating visfatin was significantly lower in the GDM than in the NGT subjects at term, although no differences in its mRNA expression in fat and placental tissues were observed.

Visfatin in human pregnancy: maternal gestational diabetes vis-à-vis neonatal birthweight

OBJECTIVE

Adipose tissue dysfunction, characterized by dysregulation of adipokines production and/or secretion, has been implicated in the pathophysiology of type-2 diabetes mellitus, a metabolic complication closely related to gestational diabetes mellitus (GDM). Recently, an association between circulating maternal visfatin, a novel adipokine with metabolic and immunoregulatory properties, and impaired glucose metabolism as well as with altered fetal growth, has been proposed. The aims of this study were to determine whether there is an association between maternal plasma visfatin concentration, GDM, and a large-for-gestational-age (LGA) newborn.

STUDY DESIGN

This cross-sectional study, included pregnant women at term in the following groups: 1) normal pregnancy and an appropriate-for-gestational-age (AGA) neonate (n=54); 2) normal pregnancy and an LGA newborn (n=47); 3) GDM and an AGA newborn (n=56); 4) GDM and an LGA newborn (n=45). The study population was further stratified by first trimester BMI (<25 vs. > or =25 kg/m(2)). Maternal plasma visfatin concentration was determined by ELISA. Parametric and non-parametric statistics were used for analysis.

RESULTS

1) Among women who delivered an AGA neonate, the median maternal plasma concentration of visfatin was higher in patients with GDM than in those with a normal pregnancy; 2) Among women with a normal pregnancy, those who delivered an LGA neonate had a higher median maternal plasma visfatin concentration than those who delivered an AGA neonate; 3) among patients with normal BMI, there were no significant differences in the median maternal plasma visfatin concentration between the four study groups; and 4) maternal GDM, as well as delivery of an LGA neonate were independently associated with a higher maternal plasma visfatin concentrations.

CONCLUSION

The linkage between increased maternal circulating visfatin and the presence of GDM or delivery of an LGA neonate supports the hypothesis that perturbation of adipokines homeostasis may play a role in the pathophysiology of GDM or excess fetal growth.

Maternal visfatin concentration in normal pregnancy

OBJECTIVE

Adipose tissue has now emerged as a powerful endocrine organ via the production of adipokines. Visfatin, a novel adipokine with diabetogenic and immuno-modulatory properties has been implicated in the pathophysiology of insulin resistance in patients with obesity and Type-2 diabetes mellitus. The aim of this study was to determine whether there are changes in the maternal plasma concentration of visfatin with advancing gestation and as a function of maternal weight.

STUDY DESIGN

In this cross-sectional study, maternal plasma concentrations of visfatin were determined in normal weight and overweight/obese pregnant women in the following gestational age groups: 1) 11-14 weeks (n=52); 2) 19-26 weeks (n=68); 3) 27-34 weeks (n=93); and 4) >37 weeks (n=60). Visfatin concentrations were determined by ELISA. Non parametric statistics were used for analysis.

RESULTS

1) The median maternal plasma visfatin concentration was higher in pregnant women between 19-26 weeks of gestation than that of those between 11-14 weeks of gestation (P<0.01) and those between 27-34 weeks of gestation (P<0.01); 2) among normal weight pregnant women, the median plasma visfatin concentrations of women between 19-26 weeks of gestation was higher than that of those between 11-14 weeks (P<0.01) and those between 27-34 weeks (P<0.01); and 3) among overweight/obese patients, the median maternal visfatin concentration was similar between the different gestational age groups.

CONCLUSION

The median maternal plasma concentration of visfatin peaks between 19-26 and has a nadir between 27-34 weeks of gestation. Normal and overweight/obese pregnant women differed in the pattern of changes in circulating visfatin concentrations as a function of gestational age.

Pre-B cell colony-enhancing factor in lower vertebrates: first evidence of this cytokine being involved in antioxidant activity by reconstruction of a novel NAD salvage pathway in E. coli

The pre-B cell colony-enhancing factor identified in mammals is an important cytokine involved in multiple functions, such as immunoregulation, cellular proliferation and differentiation. However, little is known about its existence and function in lower vertebrates; therefore, we investigated the characterization, expression and especially the biofunction of this factor in Tetraodon nigroviridis, a model organism of lower vertebrates. We focus on the question of whether the pre-B cell colony-enhancing factor of lower vertebrates contributes to the NAD mediated antioxidant activity by its involvement in the biosynthesis of NAD through pyridine nucleotide cycles. Experimental data demonstrated that by transforming fish pre-B cell colony-enhancing factor into Escherichia coli cells, the amounts of NAD and NADP significantly increased, and cellular antioxidant activity greatly improved. This is the first report about vertebrate pre-B cell colony-enhancing factor acting as a nicotinamide phosphoribosyltransferase to reconstruct a pyridine nucleotide cycle III pathway in E. coli and playing an important role in antioxidant stress by up-regulation of NAD biosynthesis. We hope that our observations may enrich the study of pre-B cell colony-enhancing factor, and contribute to a better understanding of the molecular and functional evolution of the pre-B cell colony-enhancing factor family in both lower vertebrates and mammals as a whole.

Visfatin/Pre-B cell colony-enhancing factor in amniotic fluid in normal pregnancy, spontaneous labor at term, preterm labor and prelabor rupture of membranes: an association with subclinical intrauterine infection in preterm parturition

OBJECTIVE

Visfatin, a novel adipokine originally discovered as a pre-B-cell colony enhancing factor, is expressed by amniotic epithelium, cytotrophoblast, and decidua and is over-expressed when fetal membranes are exposed to mechanical stress and/or pro-inflammatory stimuli. Visfatin expression by fetal membranes is dramatically up-regulated after normal spontaneous labor. The aims of this study were to determine if visfatin is detectable in amniotic fluid (AF) and whether its concentration changes with gestational age, spontaneous labor, preterm prelabor rupture of membranes (preterm PROM) and in the presence of microbial invasion of the amniotic cavity (MIAC).

METHODS

In this cross-sectional study, visfatin concentration in AF was determined in patients in the following groups: 1) mid-trimester (n=75); 2) term not in labor (n=27); 3) term in spontaneous labor (n=51); 4) patients with preterm labor with intact membranes (PTL) without MIAC who delivered at term (n=35); 5) patients with PTL without MIAC who delivered preterm (n=52); 6) patients with PTL with MIAC (n=25); 7) women with preterm PROM without MIAC (n=26); and 8) women with preterm PROM with MIAC (n=26). Non-parametric statistics were used for analysis.

RESULTS

1) The median AF concentration of visfatin was significantly higher in patients at term than in mid-trimester; 2) Among women with PTL who delivered preterm, the median visfatin concentration was significantly higher in patients with MIAC than those without MIAC; 3) Similarly, patients with PTL and MIAC had a higher median AF visfatin concentration than those with PTL who delivered at term; 4) Among women with preterm PROM, the median AF visfatin concentration was significantly higher in patients with MIAC than those without MIAC.

CONCLUSIONS

1) Visfatin is a physiologic constituent of AF; 2) The concentration of AF visfatin increases with advancing gestational age; 3) AF visfatin concentration is elevated in patients with MIAC, regardless of the membrane status, suggesting that visfatin participates in the host response against infection.

Gene organization, alternate splicing and expression pattern of porcine visfatin gene

Visfatin is a newly discovered visceral fat-specific adipocytokine. It is upregulated in obesity and exerts insulin-mimetic effects in various tissues in human and mouse. We reported here the cloning and characterization of porcine visfatin, its three alternate splicing variants. Sequence analysis indicated that variant 1 is the predominant form among species, which contains an open reading frame of 1473 bp encoding a 52-kDa protein of 491 amino acids. While the other two variants were predicted to encode two 3' truncated proteins due to early termination. The nucleotide and amino acid sequences deduced from variant 1 were conservative across species. The porcine visfatin gene was composed of 11 exons at least and had exactly the same exon/intron structure as the human orthologs. Nested PCR showed that variants 1 and 3 were ubiquitously expressed in porcine tissues and that variant 2 was expressed in most tissues examined with exception of testis and liver. The discovery of the three variants of visfatin in porcine would be useful to the further investigation of the function of the visfatin gene.

Pre-B-cell Colony-enhancing Factor (PBEF/Visfatin) Gene Expression is Modulated by NF-κB and AP-1 in Human Amniotic Epithelial Cells

A localized intrauterine inflammatory response is often associated with the initiation of normal human parturition, whereas infection causes a similar but more florid response initiating preterm labor. Pre-B-cell colony-enhancing factor (PBEF) is expressed in the human fetal membranes and is up-regulated by labor, severe infection and inflammatory stimuli. The aim of this study was to determine the involvement of the transcription factors NF-kappaB and AP-1 in the response of PBEF to an inflammatory stimulus and compare it with IL-8. The results showed that this treatment of amniotic epithelial-like cells (WISH) and primary amniotic epithelial cells increased expression of PBEF and IL-8, but IL-8 responded 100-fold more than PBEF. IL-1beta treatment together with a panel of NF-kappaB and AP-1 inhibitors demonstrated the involvement of these transcription factors in the up-regulation of PBEF. These data show that an inflammatory stimulus in the fetal membranes inducing NF-kappaB and AP-1 would up-regulate PBEF as well as IL-8.

Visfatin/pre-B-cell colony-enhancing factor: a protein with various suggested functions

Pre-B-cell colony-enhancing factor (PBEF) was recently found in high levels in visceral fat, and was therefore renamed visfatin. This new adipocytokine exerts insulin-mimetic effects in mice and in cultured cells by binding to and activating the insulin receptor. Despite some recent studies on this topic, the proposed role of visfatin in metabolism remains largely unknown. Initially, PBEF/visfatin was discovered as a cytokine for the differentiation of B-cells. Pre-B-cell colony-enhancing factor was also shown to inhibit apoptosis of neutrophils in sepsis and was discussed as a novel biomarker for acute lung injury (ALI). Although PBEF is missing a signal sequence, its secretion and function as a molecule involved in the regulation of inflammatory processes was reported in several studies. Investigations of PBEF/visfatin in gestational membranes suggest a function in the physiologic and pathologic pathways leading to labor. Furthermore, it was found upregulated in colorectal cancer and was brought into connection with the regulation of the cell cycle. Intra-cellular, PBEF/visfatin acts as a cytosolic enzyme involved in nicotinamide adenine dinucleotide (NAD) synthesis. This activity was shown to be important for vascular smooth muscle cell (SMC) maturation, indicating a possible involvement in vascular pathology. The important physiologic role of PBEF/visfatin is also underlined by its evolutionary highly conserved gene in different species. This review summarizes the current knowledge of the various functions of PBEF/visfatin towards involvements in pathophysiology of several diseases.

Human spontaneous labor without histologic chorioamnionitis is characterized by an acute inflammation gene expression signature

OBJECTIVE

The purpose of this study was to identify which biological processes may be involved in normal labor.

STUDY DESIGN

Transcriptional profiles for chorioamniotic membranes (n = 24) and blood (n = 20) were generated from patients at term with no labor (TNL) and in labor (TIL).

RESULTS

Expression of 197 transcripts (P < or = .02) differentiated TIL and TNL chorioamniotic membrane samples. Gene Ontology analysis indicated that TIL samples had increased expression of multiple chemokines and transcripts associated with neutrophil and monocyte recruitment. Microarray results were verified using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) with independent samples. Transcriptional profiles from blood RNA revealed no Gene Ontology category enrichment of discriminant probe sets.

CONCLUSION

Labor induces gene expression changes consistent with localized inflammation, despite the absence of histologically detectable inflammation.

Microarray analysis of regional cellular responses to local mechanical stress in acute lung injury

Human acute lung injury is characterized by heterogeneous tissue involvement, leading to the potential for extremes of mechanical stress and tissue injury when mechanical ventilation, required to support critically ill patients, is employed. Our goal was to establish whether regional cellular responses to these disparate local mechanical conditions could be determined as a novel approach toward understanding the mechanism of development of ventilator-associated lung injury. We utilized cross-species genomic microarrays in a unilateral model of ventilator-associated lung injury in anesthetized dogs to assess regional cellular responses to local mechanical conditions that potentially contribute pathogenic mechanisms of injury. Highly significant regional differences in gene expression were observed between lung apex/base regions as well as between gravitationally dependent/nondependent regions of the base, with 367 and 1,544 genes differentially regulated between these regions, respectively. Major functional groupings of differentially regulated genes included inflammation and immune responses, cell proliferation, adhesion, signaling, and apoptosis. Expression of genes encoding both acute lung injury-associated inflammatory cytokines and protective acute response genes were markedly different in the nondependent compared with the dependent regions of the lung base. We conclude that there are significant differences in the local responses to stress within the lung, and consequently, insights into the cellular responses that contribute to ventilator-associated lung injury development must be sought in the context of the mechanical heterogeneity that characterizes this syndrome.

Pre-B-cell-colony-enhancing factor is critically involved in thrombin-induced lung endothelial cell barrier dysregulation

Prior genomic and genetic studies identified pre-B-cell colony-enhancing factor (PBEF) as a novel candidate gene and biomarker in acute lung injury (ALI). As increased vascular permeability is a cardinal feature of ALI, we assessed the role of PBEF in in vitro vascular barrier regulation using confluent human pulmonary artery endothelial cell (HPAEC) monolayers. Reductions in PBEF protein expression (>70%) by siRNA significantly attenuated EC barrier dysfunction induced by the potent edemagenic agent, thrombin, reflected by reductions in transendothelial electric resistance (TER, approximately 60% reduction). Furthermore, PBEF siRNA blunted thrombin-mediated increases in Ca(2+) entry, polymerized actin formation, and myosin light chain phosphorylation, events critical to the thrombin-mediated permeability response. Finally, PBEF siRNA also significantly inhibited thrombin-stimulated increase of IL-8 secretion in HPAEC, a chemokine known to induce actin fiber formation and intercellular gap formation of endothelial cells. Taken together, these studies demonstrate that PBEF may be required for complete expression of the thrombin-induced inflammatory response and reveal potentially novel role for PBEF in the regulation of EC Ca(2+)-dependent cytoskeletal rearrangement and endothelial barrier dysfunction. Ongoing studies will continue to address the molecular mechanisms by which PBEF contributes to ALI susceptibility.

Pre-B-cell colony-enhancing factor is a secreted cytokine-like protein from the human amniotic epithelium

OBJECTIVE

The purpose of this study was to determine whether pre-B-cell colony-enhancing factor is a secreted cytokine in the human amnion and to study its chemotaxic and antiapoptotic properties.

STUDY DESIGN

Pre-B-cell colony-enhancing factor secretion was studied from amniotic epithelial-like WISH cells and primary amniotic epithelial cells that were seeded on squares of immobilon-P membrane and stimulated with lipopolysaccharide or tumor necrosis factor-alpha, respectively. The pre-B-cell colony-enhancing factor protein was detected both intracellularly and after secretion, as bound to the membrane, by immunostaining and densitometry. Medium and cell lysates that were obtained from WISH cells that were treated with lipopolysaccharide alone or together with a pre-B-cell colony-enhancing factor antisense oligonucleotide to block pre-B-cell colony-enhancing factor translation were also analyzed for secreted pre-B-cell colony-enhancing factor by Western blotting and densitometry. A chemotaxic effect of pre-B-cell colony-enhancing factor on human neutrophils was compared with the chemoattractants interleukin-8 and N-Formyl-Met-Leu-Phe methyl ester in a rapid fluorescence-based neutrophil migration assay. Apoptosis was induced in primary amniotic epithelial cells and fibroblasts by actinomycin D (1 microg/mL); the antiapoptotic effects of pre-B-cell colony-enhancing factor on early apoptosis were measured by the annexin V assay, and the late effects were determined by measurement of nuclear matrix protein in the media.

RESULTS

Treatment of amnion cells that adhered to immobilon-P membrane to induce the secretion of pre-B-cell colony-enhancing factor showed significantly (P<.05) more pre-B-cell colony-enhancing factor protein surrounding the cells compared with the controls. Although the addition of lipopolysaccharide to cultured WISH cells caused the secretion of pre-B-cell colony-enhancing factor into the medium, co-treatment with an antisense oligonucleotide to pre-B-cell colony-enhancing factor obliterated it. Analysis of the cell lysates showed no significant change, which suggests that most of the pre-B-cell colony-enhancing factor protein had been secreted. No significant chemotaxic effects of pre-B-cell colony-enhancing factor were observed; however, pre-B-cell colony-enhancing factor treatment (100 ng/mL), together with actinomycin D, cancelled the early induction of apoptosis, although there was a dose-dependent and significant late antiapoptotic effect on primary amnion epithelial cells (P<.001) and fibroblasts (P<.01).

CONCLUSION

Pre-B-cell colony-enhancing factor is a secreted protein from amniotic epithelial cells. Although it had no chemotaxic effects, it was antiapoptotic for both amniotic epithelial cells and fibroblasts and may protect these cells against apoptosis that is induced by chronic distension, labor, or infection.

Pre-B-cell colony-enhancing factor regulates NAD+-dependent protein deacetylase activity and promotes vascular smooth muscle cell maturation

Conversion of vascular smooth muscle cells (SMCs) from a proliferative state to a nonproliferative, contractile state confers vasomotor function to developing and remodeling blood vessels. Using a maturation-competent human SMC line, we determined that this shift in phenotype was accompanied by upregulation of pre-B-cell colony-enhancing factor (PBEF), a protein proposed to be a cytokine. Knockdown of endogenous PBEF increased SMC apoptosis and reduced the capacity of synthetic SMCs to mature to a contractile state. In keeping with these findings, human SMCs transduced with the PBEF gene had enhanced survival, an elongated bipolar morphology, and increased levels of h-caldesmon, smoothelin-A, smoothelin-B, and metavinculin. Notwithstanding some prior reports, PBEF did not have attributes of a cytokine but instead imparted the cell with increased nicotinamide phosphoribosyltransferase activity. Intracellular nicotinamide adenine dinucleotide (NAD+) content was increased in PBEF-overexpressing SMCs and decreased in PBEF-knockdown SMCs. Furthermore, NAD+-dependent protein deacetylase activity was found to be essential for SMC maturation and was increased by PBEF. Xenotransplantation of human SMCs into immunodeficient mice revealed an increased capacity for PBEF-overexpressing SMCs to mature and intimately invest nascent endothelial channels. This microvessel chimerism and maturation process was perturbed when SMC PBEF expression was lowered. These findings identify PBEF as a regulator of NAD+-dependent reactions in SMCs, reactions that promote, among other potential processes, the acquisition of a mature SMC phenotype.

Molecular Cloning and Characterization of Canine Pre-B-Cell Colony-Enhancing Factor

During our previous attempt to search for the candidate genes to acute lung injury (ALI), we unexpectedly identified PBEF as the most highly upregulated gene in a canine model of ALI by crosshybridizing canine lung cRNA to the Affymetrix human gene chip HG-U133A. The result suggested that PBEF may be a potential biomarker in ALI. To extend and translate that finding, we have performed the molecular cloning and characterization of canine PBEF cDNA in this study. Deduced amino acid sequence alignment revealed that the PBEF gene is evolutionarily highly conserved, with the canine PBEF protein sequence 96% identical to human PBEF and 94% identical to both murine and rat PBEF counterparts. Canine PBEF protein was successfully expressed both by in vitro transcription coupled with translation in a cell-free system and by transfection of canine PBEF cDNA into the human lung type II alveolar adenocarcinoma cell line A549. The expressed canine PBEF protein was visualized by either an anti-V5 tag peptide polyclonal antibody or an anti-canine PBEF peptide polyclonal antibody. RT-PCR assay indicates that canine PBEF is expressed in canine lung, brain, heart, liver, spleen, kidney, pancreas, and muscle, with liver showing the highest expression,followed by muscle. Isolation of the canine PBEF cDNA and expression of its recombinant protein may provide molecular tools to study the molecular mechanism of ALI in the canine model and to elucidate the potential role of PBEF as an ALI biomarker.

Pre-B-cell colony-enhancing factor as a potential novel biomarker in acute lung injury

Although the pathogenic and genetic basis of acute lung injury (ALI) remains incompletely understood, the identification of novel ALI biomarkers holds promise for unique insights. Expression profiling in animal models of ALI (canine and murine) and human ALI detected significant expression of pre-B-cell colony-enhancing factor (PBEF), a gene not previously associated with lung pathophysiology. These results were validated by real-time polymerase chain reaction and immunohistochemistry studies, with PBEF protein levels significantly increased in both bronchoalveolar lavage fluid and serum of ALI models and in cytokine- or cyclic stretch-activated lung microvascular endothelium. We genotyped two PBEF single-nucleotide polymorphisms (SNPs) in a well characterized sample of white patients with sepsis-associated ALI, patients with severe sepsis, and healthy subjects and observed that carriers of the haplotype GC from SNPs T-1001G and C-1543T had a 7.7-fold higher risk of ALI (95% confidence interval 3.01-19.75, p < 0.001). The T variant from the SNP C-1543T resulted in a significant decrease in the transcription rate (1.8-fold; p < 0.01) by the reporter gene assay. Together, these results strongly indicate that PBEF is a potential novel biomarker in ALI and demonstrate the successful application of robust genomic technologies in the identification of candidate genes in complex lung disease.

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