Pro-inflammatory gene expression profile in obese adults with high plasma GIP levels.

BACKGROUND: Glucose-dependent insulinotropic peptide (GIP) provides a novel link between the immune system and the gut, although results from different experimental and observational studies are contradictory, ranging from anti-inflammatory, through neutral to pro-inflammatory action of GIP. Thus, the aim of this study was to analyze inflammatory pathways on the level of gene expression and circulating inflammatory markers in relation to plasma GIP level. SUBJECTS/METHODS: The study included 128 obese adults. Two groups of obese subjects were created according to fasting GIP levels, with cutoff point at the 66th percentile and compared in respect with molecular and circulating markers of inflammation. GIP, interleukin (IL)-6 and adipokines: leptin, adiponectin, visfatin were measured by enzyme-linked immunosorbent assay. Inflammatory markers: monocyte chemoattractant protein-1 (MCP-1), sE-Selectin, sVCAM-1, sPECAM-1 were studied at fasting and after nutrient challenges. Gene expression in blood cells was determined by human gene microarray. RESULTS: Obese patients with high GIP levels had elevated fasting glucose (Q2 (Q1-Q3): 5.6 (5.0-6.0) vs 5.0 (4.8-5.4), P<0.001), homeostasis model assessment of insulin resistance (Q2 (Q1-Q3): 3.68 (2.72-5.42) vs 2.70 (2.13-4.33), P=0.021), thus increased markers of insulin resistance as well as elevated inflammatory markers Il-6 (Q2 (Q1-Q3): 1.34 (1.0-2.04) vs 1.12 (0.76-1.64), P=0.045), MCP-1 (Q2 (Q1-Q3): 363 (287-447) vs 323 (263-389), P=0.026). Leptin to adiponectin ratio was significantly associated with fasting plasma GIP levels (ß (95% CI): 0.84 (0.10-1.59)) independently of glucose levels. sE-Selectin was found to be a factor influencing GIP response to oral glucose intake (ß (95% CI): 0.47 (0.14-0.81)) and sVCAM was found to be a factor influencing GIP response to high-fat meal intake (ß (95% CI): 0.19 (0.01-0.37)). We identified 32 genes of inflammatory pathways differentially expressed in subjects with a high plasma GIP level compared to low GIP. Most upregulated genes play a role in leukocyte chemotaxis and tissue infiltration. CONCLUSIONS: These findings support the hypothesis that increased GIP signaling has a role in chronic low-grade inflammation.

Assessment of incretins in oral glucose and lipid tolerance tests may be indicative in the diagnosis of metabolic syndrome aggravation.

Incretins stimulated by oral meals are claimed to be protective for the pancreatic beta cells, to increase insulin secretion, to inhibit glucagon release, slow gastric emptying (glucagon-like peptide-1) and suppress appetite. Recently it has however been suggested that glucagon-like peptide-1 (GLP-1) is putative early biomarker of metabolic consequences of the obesity associated proinflammatory state. The study was aimed to compare the release of incretins and some of early markers of inflammation at the fasting and postprandial period induced by functional oral glucose as well as lipid load in healthy controls and patients with metabolic syndrome (MS) to see if functional tests may be helpful in searching for the inflammatory status of patients. Fifty patients with MS and 20 healthy volunteers (C) participated in this study. The 3-hour oral glucose (OGTT) and the 8-hour oral lipid (OLTT) tolerance tests were performed. At fasting leptin and adiponectin, as well as every 30 minutes of OGTT and every 2 hours of OLTT blood concentration of GLP-1, glucose-dependent insulinotropic polypeptide (GIP), glucose, insulin, triglycerides, free fatty acids, glutathione peroxidase, interleukin-6, sE-selectin, monocyte chemoattractant protein-1 (MCP1) and visfatin were measured. At fasting and during both OGTT and OLTT the level of incretins did not differ between the MS and the C group. Both glucose and lipids reach food activated incretins secretion. Glucose was the main GLP-1 release activator, while the lipid load activated evidently GIP secretion. A significantly larger AUC-GIP after the lipid-rich meal over the carbohydrate meal was observed, while statistically bigger value of AUC-GLP-1 was noticed in OGTT than in OLTT (P < 0.001) within each of the investigated groups. In patients with the highest fasting plasma GIP concentration (3(rd) tertile), IL-6, MCP-1, sE-selectin and visfatin blood levels were increased and correlated with glutathione peroxydase, leptin/adiponectin ratio, higher visfatin and interleukin-6 levels. The fat containing meals stimulate the long-lasting release of incretins, mainly GIP, parallel to the increase of the markers of low grade inflammation associating obesity in metabolic syndrome. The possibility of use of the postprandial (OLTT) GIP release measurement for the low grade inflammation progress in MS patients is suggested.

Influence of oxy-LDL and interleukin-8 on the platelet/PMNs adhesion and on chemotaxis-mediated induction of iNOS in neutrophils.

Selectin-P expression on platelets stimulated with thrombin was measured in terms of formation of "rosettes" according to Jungi et al. [9]. Selectin-P-mediated platelet/PMNs adhesion was inhibited by iloprost (IC50 = 5.0 nM), sodium nitroprusside (NaNP, IC50 = 0.93 microM) and interleukin-8 (IL-8, IC50 = 88 ng/ml), but activated dose-dependently by oxy-LDL (3-15 micrograms/ml). Glycogen-induced peritonitis in rats up-regulated the iNOS activity measured by the 2,3-[3H]-citrulline formation by the abdominal cavity PMNs up to 6 h after insult. Pretreatment with IL-8 (3 micrograms/300 g iv) decreased the amount of PMNs in ascites as well as its iNOS activity. Chemotaxis mediated iNOS gene expression of PMNs were measured by Northern blot hybridization. IL-8 (100 ng/ml) did not influence the PMNs iNOS gene expression induced by chemotaxis. We conclude that the decrease in iNOS activity by IL-8 involves postranslational modification of the enzyme activity.

Luminol-chemiluminescence in free peritoneal cells in hemorrhagic shock in rats treated with PAF-receptor-antagonist BN 52021.

The activity of rat peritoneal cells were assessed by the phorbol mirystinian acetate (PMA)-induced luminol chemiluminescence (LCL). Results in control groups (0 - no manipulation, and I - carotid artery cannulation) were compared with those in the untreated hemorrhagic shock (group II), in the shock treated with the standard polyelectrolyte solution (PES) (group III), and in shock treated with PAF receptor-antagonist BN 52021 + PES (group IV). The maximal and the most rapid LCL was observed in the group treated with BN 52021 (group IV), while chemiluminescent response in the the untreated shock (group II) and in shock treated with PES was minimally expressed and late. The findings indicate for a rapid activation of peritoneal cells during ca 1 hour of hemorrhagic shock. This leads to exhausting their ability to the superoxide anion generation 15 minutes later. Peritoneal cells obtained from the group treated with the BN 52021 revealed a preserved ability to the respiratory burst. It can be concluded that BN 52021 effectively inhibits activation of the PC during hemorrhagic shock.

Seasonal variations in male mice at the time of sexual maturation.

The sexual maturation of male mice reared under constant laboratory conditions was studied in animals born in different months of the year. The body weights were significantly affected by the month of birth. Males born in March and May were heavier at 4 and 5 weeks of age than those born in autumn and winter. As indicated by the relative weights of accessory glands, males born in spring matured earlier compared with animals born in other months of the year. Variation in the relative testicular weights during maturation was not influenced by the month of birth. Female mice also showed a significant relationship between the month of birth and sexual maturation. Females born in March reached puberty, as measured by the age of vaginal opening and first oestrus, earlier than those born in other months of the year.