Modulation of cytokine secretion by pentacyclic triterpenes from olive pomace oil in human mononuclear cells

Olive pomace oil, also known as "orujo" olive oil, is a blend of refined-pomace oil and virgin olive oil, fit for human consumption. Maslinic acid, oleanolic acid, erythrodiol, and uvaol are pentacyclic triterpenes, found in the non-glyceride fraction of orujo oil, which have previously been reported to have anti-inflammatory properties. In the present work, we investigated the effect of these minor components on pro-inflammatory cytokine production by human peripheral blood mononuclear cells in six different samples. Uvaol, erythrodiol, and oleanolic acid significantly decreased IL-1 beta and IL-6 production in a dose-dependent manner. All three compounds significantly reduced TNF-alpha production at 100 mu M; however, at 10 mu M, uvaol and oleanolic acid enhanced the generation of TNF-alpha. In contrast, maslinic acid did not significantly alter the concentration of those cytokines, with the exception of a slight inhibitory effect at 100 mu M. All four triterpenes inhibited production of I-309, at 50 mu M and 100 mu M. However, uvaol enhanced I-309 production at 10 mu M. The triterpenic dialcohols had a similar effect on MIG production. In conclusion, this study demonstrates that pentacyclic triterpenes in orujo oil exhibit pro- and anti-inflammatory properties depending on chemical structure and dose, and may be useful in modulating the immune response. (c) 2006 Elsevier Ltd. All rights reserved.

Impact of saturated, polyunsaturated and monounsaturated fatty acid-rich micelles on lipoprotein synthesis and secretion in Caco-2 cells

Meal fatty acids have been shown to modulate the size and composition of triacylglycerol (TAG)-rich lipoproteins influencing the magnitude and duration of the postprandial plasma TAG response. As a result there is considerable interest in the origin of these meal fatty-acid induced differences in particle composition. Caco-2 cells were incubated over 4 days with fatty acid mixtures resembling the composition of saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA)-rich meals fed in a previous postprandial study to determine their impact on lipoprotein synthesis and secretion. The MUFA- and PUFA-rich mixtures supported greater intracellular TAG, but not cholesterol accumulation compared with the SFA-rich mixture (P < 0.001). The MUFA-rich mixture promoted significantly greater TAG and cholesterol secretion than the other mixtures and significantly more apolipoprotein B-100 secretion than the PUFA-rich mixture (P < 0.05). Electron microscopy revealed the SFA-rich mixture had led to unfavourable effects on cellular morphology, compared with the unsaturated fatty acid-rich mixtures. Our findings suggest the MUFA-rich mixture, may support the formation of a greater number of TAG-rich lipoproteins, which is consistent with indirect observations from our human study. Our electron micrographs are suggestive that some endocytotic uptake of MUFA-rich taurocholate micelles may promote greater lipoprotein synthesis and secretion in Caco-2 cells.

Casein and whey exert different effects on plasma amino acid profiles, gastrointestinal hormone secretion and appetite

Protein, generally agreed to be the most satiating macronutrient, may differ in its effects on appetite depending on the protein source and variation in digestion and absorption. We investigated the effects of two milk protein types, casein and whey, on food intake and subjective ratings of hunger and fullness, and on postprandial metabolite and gastrointestinal hormone responses. Two studies were undertaken. The first study showed that energy intake from a buffet meal ad libitum was significantly less 90 min after a 1700 kJ liquid preload containing 48 g whey, compared with an equivalent casein preload (P<0.05). In the second study, the same whey preload led to a 28 % increase in postprandial plasma amino acid concentrations over 3 h compared with casein (incremental area under the curve (iAUC), P<0.05). Plasma cholecystokinin (CCK) was increased by 60 % (iAUC, P<0.005), glucagon-like peptide (GLP)-1 by 65 % (iAUC, P<0.05) and glucose-dependent insulinotropic polypeptide by 36 % (iAUC, P<0.01) following the whey preload compared with the casein. Gastric emptying was influenced by protein type as evidenced by differing plasma paracetamol profiles with the two preloads. Greater subjective satiety followed the whey test meal (P<0.05). These results implicate post-absorptive increases in plasma amino acids together with both CCK and GLP-1 as potential mediators of the increased satiety response to whey and emphasise the importance of considering the impact of protein type on the appetite response to a mixed meal.

Disturbances in morning cortisol secretion in association with maternal postnatal depression predict subsequent depressive symptomatology in adolescents

Background: We have previously reported higher and more variable salivary morning cortisol in 13-year-old adolescents whose mothers were depressed in the postnatal period, compared with control group adolescents whose mothers did not develop postnatal depression (PND). This observation suggested a biological mechanism by which intrafamilial risk for depressive disorder may be transmitted. In the current article, we examined whether the cortisol disturbances observed at 13 years could predict depressive symptornatology in adolescents at 16 years of age. Methods: We measured self-reported depressive symptoms in 16-year-old adolescents who had (n = 48) or had not (n = 39) been exposed to postnatal maternal depression and examined their prediction by morning and evening cortisol indices obtained via 10 days of salivary collections at 13 years. Results: Elevated morning cortisol secretion at 13 years, and particularly the maximum level recorded over 10 days of collection, predicted elevated depressive symptoms at 16 years over and above 13-year depressive symptom levels and other possible confounding factors. Morning cortisol secretion mediated an association between maternal PND and symptornatology in 16-year-old offspring. Conclusions: Alterations in steroid secretion observed in association with maternal PND may provide a mechanism by which risk for depression is transmitted from mother to offspring.

Serum vitamin D concentration does not predict insulin action or secretion in European subjects with the metabolic syndrome

OBJECTIVE To investigate the relation between serum concentration of 25-hydroxyvitamin D [25(OH)D] and insulin action and secretion. RESEARCH DESIGN AND METHODS In a cross-sectional study of 446 Pan-European subjects with the metabolic syndrome, insulin action and secretion were assessed by homeostasis model assessment (HOMA) indexes and intravenous glucose tolerance test to calculate acute insulin response, insulin sensitivity, and disposition index. Serum 25(OH)D was measured by high-performance liquid chromatography/mass spectrometry. RESULTS The 25(OH)D3 concentration was 57.1 ± 26.0 nmol/l (mean ± SD), and only 20% of the subjects had 25(OH)D3 levels ≥75 nmol/l. In multiple linear analyses, 25(OH)D3 concentrations were not associated with parameters of insulin action or secretion after adjustment for BMI and other covariates. CONCLUSIONS In a large sample of subjects with the metabolic syndrome, serum concentrations of 25(OH)D3 did not predict insulin action or secretion. Clear evidence that D vitamin status directly influences insulin secretion or action is still lacking.

Disturbances in early parenting of depressed mothers and cortisol secretion in offspring: A preliminary study

Background: Disturbances in cortisol secretion are associated with risk for psychiatric disorder, including depression. Animal research indicates that early care experiences influence hypothalamic-pituitary-adrenal (HPA) axis functioning in offspring. Similar effects are suggested in human development, but evidence of longitudinal associations between observed early parenting and offspring cortisol secretion is extremely limited. We studied associations between parenting disturbances occurring in the context of maternal postnatal depression (PND), and elevations in morning cortisol secretion in the adolescent offspring of PND mothers. Methods: We observed maternal parenting behaviour on four occasions through the first year and at five-year follow up in postnatally depressed (n = 29) and well (n = 20) mothers. Observations were coded for maternal sensitivity and withdrawal. Basal offspring salivary cortisol secretion was measured at 13-years, using collections over 10-days. Results: Postnatal, but not five-year, maternal withdrawal predicted elevated mean and maximum morning cortisol secretion in 13-year-old offspring. There were no significant associations between maternal sensitivity and offspring cortisol secretion. Limitations: The sample size was relatively small, and effects tended to be reduced to trend level when covariates were considered. The correlational nature of the study (albeit longitudinal) limits conclusions regarding causality. Conclusions: Individual differences in early maternal parenting behaviour may influence offspring cortisol secretion, and thereby risk for depression. Parenting interventions that facilitate active maternal engagement with the infant may be indicated for high risk populations.

Impact of gut passage and mucus secretion by the earthworm Lumbricus terrestris on mobility and speciation of arsenic in contaminated soil

Earthworms inhabiting arsenic contaminated soils may accelerate the leaching of As into surface and ground waters. We carried out three experiments to determine the impact of passage of As contaminated soil (1150 mgAs kg−1) through the gut of the earthworm Lumbricus terrestris on the mobility and speciation of As and the effects of earthworm mucus on As mobility. The concentration of water soluble As in soil increased (from 1.6 to 18 mg kg−1) after passage through the earthworm gut. Casts that were aged for 56 days still contained more than nine times greater water soluble As than bulk earthworm inhabited soil. Changes were due to increases in As(V) mobility, with no change in As(III). Dilute mucus extracts reduced As mobility through the formation of As-amino acid-iron oxide ternary complexes. More concentrated mucus extracts increased As mobility. These changes, together with those due to the passage through the gut, were due to increases in pH, phosphate and soluble organic carbon. The mobilisation of As from contaminated soils in the environment by cast production and mucus secretion may allow for accelerated leaching or uptake into biota which is underestimated when bulk soil samples are analysed and the influence of soil biota ignored.

Genetic predisposition to type 2 diabetes is associated with impaired insulin secretion but does not modify insulin resistance or secretion in response to an intervention to lower dietary saturated fat

Genome-wide association studies have identified SNPs reproducibly associated with type 2 diabetes (T2D). We examined the effect of genetic predisposition to T2D on insulin sensitivity and secretion using detailed phenotyping in overweight individuals with no diagnosis of T2D. Furthermore, we investigated whether this genetic predisposition modifies the responses in beta-cell function and insulin sensitivity to a 24-week dietary intervention. We genotyped 25 T2D-associated SNPs in 377 white participants from the RISCK study. Participants underwent an IVGTT prior to and following a dietary intervention that aimed to lower saturated fat intake by replacement with monounsaturated fat or carbohydrate. We composed a genetic predisposition score (T2D-GPS) by summing the T2D risk-increasing alleles of the 25 SNPs and tested for association with insulin secretion and sensitivity at baseline, and with the change in response to the dietary intervention. At baseline, a higher T2D-GPS was associated with lower acute insulin secretion (AIRg 4% lower/risk allele, P = 0.006) and lower insulin secretion for a given level of insulin sensitivity, assessed by the disposition index (DI 5% lower/risk allele, P = 0.002), but not with insulin sensitivity (Si). T2D-GPS did not modify changes in insulin secretion, insulin sensitivity or the disposition index in response to the dietary interventions to lower saturated fat. Participants genetically predisposed to T2D have an impaired ability to compensate for peripheral insulin resistance with insulin secretion at baseline, but this does not modify the response to a reduction in dietary saturated fat through iso-energetic replacement with carbohydrate or monounsaturated fat.

Transcriptional regulators of the GAD acid stress island are carried by effector protein-encoding prophages and indirectly control type III secretion in enterohemorrhagic Escherichia coli O157:H7

P>Type III secretion (T3S) plays a pivotal role in the colonization of ruminant hosts by Enterohemorrhagic Escherichia coli (EHEC). The T3S system translocates effector proteins into host cells to promote bacterial attachment and persistence. The repertoire and variation in prophage regions underpins differences in the pathogenesis and epidemiology of EHEC strains. In this study, we have used a collection of deletions in cryptic prophages and EHEC O157 O-islands to screen for novel regulators of T3S. Using this approach we have identified a family of homologous AraC-like regulators that indirectly repress T3S. These prophage-encoded secretion regulator genes (psr) are found exclusively on prophages and are associated with effector loci and the T3S activating Pch family of regulators. Transcriptional profiling, mutagenesis and DNA binding studies were used to show that these regulators usurp the conserved GAD acid stress resistance system to regulate T3S by increasing the expression of GadE (YhiE) and YhiF and that this regulation follows attachment to bovine epithelial cells. We further demonstrate that PsrA and effectors encoded within cryptic prophage CP933-N are required for persistence in a ruminant model of colonization.

Type III secretion homologs are present in Brucella melitensis, B-ovis, and B-suis biovars 1, 2, and 3

Protein sequences from characterized type III secretion (TTS) systems were used as probes in silico to identify several TTS gene homologs in the genome sequence of Brucella suis biovar 1 strain 1330. Four of the genes, named flhB, fliP, fliR, and fliF on the basis of greatest homologies to known flagellar apparatus proteins, were targeted in PCR and hybridization assays to determine their distribution among other Brucella nomen species and biovars. The results indicated that flhB, fliP, fliR and fliF are present in Brucella melitensis, Brucella ovis, and Brucella suis biovars 1, 2 and 3. Similar homologos have been reported previously in Brucella abortus. Using RT-PCR assays, we were unable to detect any expression of these genes. It is not yet known whether the genes are the cryptic remnants of a flagellar system or are actively involved in a process contributing to pathogenicity or previously undetected motility, but they are distributed widely in Brucella and merit further study to determine their role.

Mutation of toxB and a truncated version of the efa-1 gene in Escherichia coli O157 : H7 influences the expression and secretion of locus of enterocyte effacement-encoded proteins but not intestinal colonization in calves or sheep

Enterohemorrhagic Escherichia coli (EHEC) strains comprise a broad group of bacteria, some of which cause attaching and effacing (AE) lesions and enteritis in humans and animals. Non-O157:H7 EHEC strains contain the gene efa-1 (referred to in previous publications as efa1), which influences adherence to cultured epithelial cells. An almost identical gene in enteropathogenic E. coli (lifA) mediates the inhibition of lymphocyte proliferation and proinflammatory cytokine synthesis. We have shown previously that significantly lower numbers of EHEC 05 and 0111 efa-1 mutants are shed in feces following experimental infection in calves and that these mutants exhibit reduced adherence to intestinal epithelia compared with isogenic wild-type strains. E. coli O157:H7 strains lack efa-1 but encode a homolog on the pO157 plasmid (toxB/l7095) and contain a truncated version of the efa-1 gene (efa-1'/z4332 in O island 122 of the EDL933 chromosome). Here we report that E. coli O157:H7 toxB and efa-1' single and double mutants exhibit reduced adherence to cultured epithelial cells and show reduced expression and secretion of proteins encoded by the locus of enterocyte effacement (LEE), which plays a key role in the host-cell interactions of EHEC. The activity of LEE1, LEE4, and LEE5 promoters was not significantly altered in E. coli O157:H7 strains harboring toxB or efa-1' mutations, indicating that the effect on the expression of LEE-encoded secreted proteins occurs at a posttranscriptional level. Despite affecting type III secretion, mutation of toxB and efa-1' did not significantly affect the course of fecal shedding of E. coli O157:H7 following experimental inoculation of 10- to 14-day-old calves or 6-week-old sheep. Mutation of tir caused a significant reduction in fecal shedding of E. coli O157:H7 in calves, indicating that the formation of AE lesions is important for colonization of the bovine intestine.

Agonists of protease-activated receptors 1 and 2 stimulate electrolyte secretion from mouse gallbladder

Cholecystitis is one of the most common gastrointestinal diseases. Inflammation induces the activation of proteases that can signal to cells by cleaving protease-activated receptors (PARs) to induce hemostasis, inflammation, pain, and repair. However, the distribution of PARs in the gallbladder is unknown, and their effects on gallbladder function have not been fully investigated. We localized immunoreactive PAR(1) and PAR(2) to the epithelium, muscle, and serosa of mouse gallbladder. mRNA transcripts corresponding to PAR(1) and PAR(2), but not PAR(4), were detected by RT-PCR and sequencing. Addition of thrombin and a PAR(1)-selective activating peptide (TFLLRN-NH(2)) to the serosal surface of mouse gallbladder mounted in an Ussing chamber stimulated an increase in short-circuit current in wild-type but not PAR(1) knockout mice. Similarly, serosally applied trypsin and PAR(2) activating peptide (SLIGRL-NH(2)) increased short-circuit current in wild-type but not PAR(2) knockout mice. Proteases and activating peptides strongly inhibited electrogenic responses to subsequent stimulation with the same agonist, indicating homologous desensitization. Removal of HCO(3)(-) ions from the serosal buffer reduced responses to thrombin and trypsin by >80%. Agonists of PAR(1) and PAR(2) increase intracellular Ca(2+) concentration in isolated and cultured gallbladder epithelial cells. The COX-2 inhibitor meloxicam and an inhibitor of CFTR prevented the stimulatory effect of PAR(1) but not PAR(2). Thus PAR(1) and PAR(2) are expressed in the epithelium of the mouse gallbladder, and serosally applied proteases cause a HCO(3)(-) secretion. The effects of PAR(1) but not PAR(2) depend on generation of prostaglandins and activation of CFTR. These mechanisms may markedly influence fluid and electrolyte secretion of the inflamed gallbladder when multiple proteases are generated.

6-Alkyl-3,4-dihydro-2H-pyrans: Chemical Secretion Compounds in Neotropical Harvestmen

The defensive, secretions, of five neotropical) species of harvestmen, (Opiliones: Gonyleptidae) from the Brazilian Atlantic Forest were analyzed and chemically characterized by GC-MS and NMR Methods. Three of the species, Cobania picea, Roweria virescens, and Serracutisoma proximum, secrete a mixture of 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3methyl-1,4,4-benzoquinone. The secretions produced,by the Other two species Iporangaia pustulosa and Neosadocus maximus, contain 1-hepten-3-one, 5-methyl-1-hexen-3-one, and 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone. (1)as major components, as well as,2,3-dimethyl-1.,4-benzoquinone and 2-ethyl-3 methyl-1,4-benzoquinone as minor,constituents. The. dihydropyran 1-(6-butyl-3,4-dihydro-2H-pyran-2-yl)pentanone (1) is a new natural product, composed of two 1-hepten-3-one, subunits formally linked in a hetero-Diels-Alder reaction. The natural product was proven to be racemic, and its biogenetic origin is discussed.