Approximately 4% of horses suffer from one colic episode per year. The outcome is fatal in 11% of cases. F2-isoprostanes are the "gold standard" for assessment of oxidative stress in vivo and have been used extensively to quantify lipid peroxidation in association with risk factors in various diseases in humans. Because horses with colic may have intestinal ischemia and/or inflammation characterized by oxidative stress and increased production of isoprostanes, measurement of isoprostane concentrations in colicky horses may be of clinical value. The purpose of this study was to gather preliminary data on the feasibility of using urine isoprostane concentrations as an early screening tool for the severity of colic and to determine the need for surgery. The long term goal of this investigation is to reduce the number of deaths due to colic by developing a stall-side test capable of identifying horses needing surgery as early as possible and expediting their timely referral. We hypothesized that urine isoprostanes and isoprostane metabolites would be significantly higher in horses with colic compared to normal horses and that they can be used an indicator for the need for surgical intervention. Urine samples were collected from 42 normal horses and 38 horses with colic (21 medical and 22 surgical). Urine isoprostane and isoprostane metabolite concentrations were measured by mass spectrometry and normalized by urine creatinine (Cr) concentrations. Statistical analysis was performed using a one way ANOVA (Tukey's post-hoc comparison) and a 2 sample t-test. Significance was set at P<0.05. Mean (± SD) concentrations of isoprostanes and isoprostane metabolites were significantly higher in urine samples of horses with colic (2.94 ± 1.69 ng/mg Cr and 0.31 ± 0.22 ng/mg Cr, respectively) compared to healthy horses (1.89 ± 1.39 ng/mg Cr and 0.22 ± 0.08 ng/mg Cr, respectively). Urine isoprostane metabolite concentrations were significantly higher in horses undergoing surgery (0.38 ± 0.28 ng/mg Cr) compared to healthy control horses and medically treated colic horses (0.26 ± 0.11 ng/mg Cr). Non-survivors had significantly higher mean urine isoprostane metabolite concentrations (0.47 ± 0.39 ng/mg Cr) compared to healthy control horses and surviving colic horses (0.29 ± 0.24 ng/mg Cr). Since urinary concentrations of isoprostane metabolites are increased in horses suffering from colic and in non-survivor colic horses, the measurement of urine concentrations of isoprostane metabolites may be an important prognostic indicator in equine colic. / Master of Science

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 5 uppsatser.

Background: Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, the mechanisms mediating this association are speculative. Objective: The Postmenopausal Women's Alcohol Study was designed to explore the effects of moderate alcohol consumption on potential risk factors for breast cancer. In the present analysis, we evaluated the relationship of alcohol consumption with antioxidant nutrients and a biomarker of oxidative stress. Design: Participants (n = 53) consumed a controlled diet plus each of three treatments (15 or 30 g alcohol/day or a no-alcohol placebo beverage), during three 8-week periods in random order. We measured the antioxidants, vitamin E (alpha (α)- and gamma (γ-tocopherols), selenium, and vitamin C in fasting blood samples which were collected at the end of diet periods, treated and frozen for assay at the end of the study. We also measured 15-F2t-IsoP isoprostane, produced by lipid peroxidation, which serves as an indicator of oxidative stress and may serve as a biomarker for conditions favorable to carcinogenesis. Results: After adjusting for BMI (all models) and total serum cholesterol (tocopherol and isoprostane models) we observed a significant 4.6% decrease (P=0.02) in α-tocopherol and a marginally significant 4.9% increase (P = 0.07) in isoprostane levels when women consumed 30 g alcohol/day (P = 0.06 and 0.05 for overall effect of alcohol on α-tocopherol and isoprostanes, respectively). The other antioxidants were not significantly modified by the alcohol treatment. Conclusions: These results suggest that moderate alcohol consumption increases some biomarkers of oxidative stress in postmenopausal women.

La prééclampsie est caractérisée par une hypertension gestationnelle accompagnée d’une protéinurie détectable après 20 semaines de grossesse. Une invasion anormale de l’endomètre par le placenta est à l’origine de la pathophysiologie. L’apparition d’une condition hypoxique placentaire est associée à un stress oxydatif ainsi qu’à un dérèglement de la synthèse et du transport des acides gras polyinsaturés vers le fœtus. L’oxydation non enzymatique de l’acide arachidonique, un acide gras insaturé oméga-6, mène à la formation potentielle de soixante-quatre isomères de F₂-isoprostanes. Ces derniers sont d’excellents biomarqueurs du stress oxydatif et peuvent jouer un rôle de vasoconstricteurs, lorsque libérés des phospholipides des membranes cellulaires par les phospholipases A₂. J’ai étudié les niveaux d’acides gras intacts et oxydés libérés par les phospholipases A₂ ainsi que la voie du thromboxane A₂ dans le placenta de grossesses normotensives et prééclamptiques. Mes travaux ont mis en lumière que le plasmalogène, une classe particulière de phospholipides riche en acides gras polyinsaturés, est augmenté dans le placenta en prééclampsie. De plus, les F₂-isoprostanes libres se retrouvent en plus grandes concentrations dans le placenta des grossesses prééclamptiques. Parallèlement, l’expression génique de certaines phospholipases A₂ est plus élevée dans le placenta en prééclampsie que chez les contrôles. En résumé, une augmentation des F₂-isoprostanes à effet vasoconstricteur, additionné à une augmentation de l’expression génique du récepteur au thromboxane A₂, pourraient jouer un rôle important dans l’hypertension locale placentaire en cas de prééclampsie. / Preeclampsia is a complex disorder during pregnancy. It is characterized by hypertension and proteinuria detectable after twenty weeks of gestation. An abnormal placental development/invasion is believed to be the first step of the pathophysiology. Preeclampsia is associated with an hypoxic condition, oxidative stress and the deregulation of polyunsaturated fatty acid synthesis and transfer to the growing fetus. Lipid peroxidation of arachidonic acid, an omega-6 fatty acid, lead potentially to the formation of sixty-four isomers of F₂-isoprostanes. F₂-isoprostanes are reliable biomarkers of oxidative stress and some are vasoconstrictors when released from the phospholipids membranes by phospholipases A₂. I have studied intact and oxidized fatty acids liberated by phospholipases A₂ and the thromboxane A₂ pathways in the placenta of normotensives and preeclamptic placentas. We have observed that plasmalogen, a sub-class of phospholipids enriched in polyunsaturated fatty acids, is elevated in the placenta of preeclamptic pregnancies. Furthermore, concentration of free F₂-isoprostanes is higher in preeclamptic placentas compared to controls. The latter was accompanied by elevated mRNA expression of specific phospholipases A₂ in preeclamptic placentas when compared to normotensive controls. In brief, elevated levels of free F₂-isoprostanes in addition to higher expression of thromboxane A₂ receptors could be involved in the local placental hypertension in preeclampsia.

Fresh isolated erythrocyte ghost membranes and erythrocyte suspensions were incubated with an organic hydroperoxide, tert-butyl hydroperoxide, to establish the in vitro oxidative stress models. Circulating erythrocytes from normal individuals were fractionated into subpopulations of different ages by ultracentrifugation and used as an in vivo model. In these models, membrane iPF2alpha-III content accumulation was proportional to oxidative stress and correlated with decreased membrane fluidity. In circulating erythrocytes, membrane iPF2alpha-III increased with age and inversely correlated with membrane fluidity only in the core region. / Oxidative stress is involved in the pathophysiology of a wide variety of human diseases. Isoprostanes, a family of prostaglandin derivatives, are mainly derived from free radical peroxidation of specific polyunsaturated fatty acids (PUFA). Measurement of F2-isoprostanes (F2-iPs) or one specific biologically active isomer (iPF2alpha-III) is considered to be a reliable lipid peroxidation marker in human diseases. However, the association observed between increased plasma/urine F2-iPs and diseases does not necessarily reflect tissue oxidative damages. Circulating erythrocytes, a tissue with limited biosynthetic capacity and poor repair mechanism, would offer a number of advantages for assessment of in vivo oxidative damages. In this thesis, human erythrocyte membrane iPF2alpha-III content was investigated as a new marker for in vivo oxidative stress assessment. Membrane fluidity was used as an indirect marker of cellular function. / To use membrane iPF2alpha-III in a human disease with known oxidative stress burden, 49 Chinese patients on long-term haemodialysis and 31 healthy Chinese subjects were recruited. Both plasma and membrane iPF 2alpha-III showed that haemodialysis patients had increased oxidative stress. Only membrane iPF2alpha-III, but not the conventional used plasma iPF2alpha-III, correlated with membrane fluidity. Furthermore, the significant inverse correlation between membrane iPF 2alpha-III and the core region of membrane fluidity was observed for this group of patients too. Since membrane iPF2alpha-III was shown to provide a link between oxidative stress and erythrocyte function, it would be considered as a new marker of in vivo erythrocyte oxidative stress assessment. (Abstract shortened by UMI.) / Yu Xiongwen. / "July 2005." / Advisers: Wai Kei Christopher Lam; Chung Shun Ho. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3724. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 198-223). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

L’étude des marqueurs biologiques dans la broncho-pneumopathie chronique obstructive (BPCO) et l'asthme, deux maladies respiratoires chroniques affectant des millions de personnes dans le monde, pourrait améliorer leur diagnostic, leur traitement et leur prévention.Cette thèse comprend deux parties. La première visait à évaluer l'association entre un marqueur spécifique des poumons, la protéine surfactant D (SP-D) sérique, et la BPCO, et à trouver un seuil de SP-D capable de discriminer les patients BPCO des témoins. Elle a été réalisée dans le cadre d’une étude cas-témoin au Liban incluant des patients BPCO (n=90), des asthmatiques (n=124) et des témoins (n=180). La deuxième partie visait à évaluer les associations chez les adultes des marqueurs de l’inflammation systémique (protéine C-réactive ultra-sensible, hs-CRP (n=252), et des cytokines (n=283)) et des marqueurs de dommages dus au stress oxydant (8-isoprostanes 8-IsoPs (n=258) du condensat de l’air exhalé) avec les phénotypes de l’asthme.Elle a été réalisée dans le cadre de l'étude épidémiologique longitudinale Française des facteurs génétiques et environnementaux de l'asthme (EGEA).Les résultats ont montré que les niveaux de SP-D sériques étaient associés positivement avec la BPCO et des seuils des niveaux de SP-D chez ces patients ont été identifiés avec d'excellentes valeurs discriminantes. Dans EGEA, aucune association n'a été trouvée entre les niveaux de hs-CRP sériques et le contrôle de l’asthme. Des profils de cytokines sériques (identifiés par analyse en composante principale) avec des niveaux élevés d’interleukine(IL)-1Ra et d’IL-10 ont été associés avec moins de crises d'asthme et un risque plus faible d'un mauvais contrôle de l'asthme sept ans plus tard. Les résultats des analyses préliminaires sur les associations entre les niveaux de 8-IsoPs et les phénotypes de l'asthme sont également présentés.Globalement, ces résultats ont montré l'utilité d'étudier les marqueurs biologiques en lien avec la BPCO et l'asthme. / Studying the biological markers in chronic obstructive pulmonary disease (COPD) and asthma, two chronic respiratory diseases affecting millions of individuals around the world, could improve their diagnosis, their treatment and their prevention.This thesis includes two parts. The first aimed to assess the association between a lung-specific biomarker, serum Surfactant Protein D (SP-D), and COPD, and to find cut-off points able to discriminate COPD patients from controls using SP-D levels. It was performed in a case-control study in Lebanon including COPD (n=90) and asthma patients (n=124) and controls (n=180). The second part aimed to assess the cross-sectional and longitudinal associations in adults for systemic inflammatory biomarkers (high sensitivity C reactive protein hs-CRP (n=252) and cytokines (n=283) as well as biomarkers of damage due to oxidative stress (8-Isoprostanes 8-IsoPs (n=258) from the exhaled breath condensate) and asthma outcomes.It was performed in the French longitudinal epidemiological study on the genetics and environmental factors of asthma (EGEA).Results showed that serum SP-D levels were positively associated with COPD and thresholds for SP-D levels in these patients were identified with excellent discriminant values. In EGEA, no association was found between serum hs-CRP levels and asthma control. Serum cytokine profiles (identified by principal component analysis) with high levels of interleukin (IL)-1Ra and IL-10 were associated with less asthma attacks and lower risk of poor asthma control in adults seven years later. The results of the preliminary analyses on the associations between the levels of 8-IsoPs and asthma outcomes are also presented.Overall, these results have shown the usefulness of studying the biological markers related to COPD and asthma.

Le diabète de type 2 résulte d’un déséquilibre entre les capacités de sécrétion de l’insuline par les cellules bêta-pancréatiques et son action au niveau de ses tissus cibles. Dans le prédiabète, l’hypersécrétion d’insuline compense l’insulino-résistance et cet état est généralement associé à l’obésité et à l’accumulation de tissu adipeux.L’objectif de ma thèse a été d’étudier la biocommunication entre le tissu adipeux viscéral et la cellule bêta-pancréatique lors du prédiabète et du diabète de type 2, en me focalisant sur deux médiateurs originaux, les isoprostanes et les miARNs. Nous avons observé une diminution de la sécrétion d’isoprostanes par le tissu adipeux péripancréatique au cours de l’obésité chez le rat Zucker fa/fa. Spécifiquement observé dans ce tissu adipeux ectopique, ce résultat s’explique par une induction des principales enzymes antioxydantes et une réduction de l’expression de la sPLA2 IIA chez les animaux obèses. Remarquablement, une des isoprostanes, la 15-F2t-Isoprostane ainsi que son épimère aux concentrations de 10 nM et 10 μM inhibent la sécrétion d’insuline gluco-stimulée dans les îlots pancréatiques isolés de rat Wistar. Cet effet pourrait s’expliquer par la liaison de cette isoprostane avec le récepteur au thromboxane A2, dont l’expression génétique et protéique a été mise en évidence pour la première fois dans les îlots de Langerhans et les cellules bêta. La réduction de l’inhibition de la sécrétion d’insuline chez le rat Zucker fa/fa, par une biocommunication paracrine, pourrait favoriser les mécanismes de compensation bêta-cellulaire. Par ailleurs, la production de miARNs, contenus dans des vésicules extracellulaires, par le tissu adipeux omental a été analysée chez l’homme par small RNAseq. Chez des patients obèses, la production de miARNs est modifiée lors de l’insulino-résistance et du diabète de type 2 avec des conséquences possibles sur la fonctionnalité des cellules bêta. Des miARNs différentiellement exprimés lors du diabète de type 2 pourraient ainsi participer à son apparition et représenter de nouveaux biomarqueurs et cibles thérapeutiques. Pour conclure, ces travaux de thèse ont permis de mettre en évidence de nouveaux mécanismes de biocommunication entre le tissu adipeux et les cellules bêta-pancréatiques. / Type 2 diabetes occurs as a result of an unability of pancreatic beta-cells to meet the insulin demand in its target tissues. During prediabetes insulin hypersecretion compensate for insulin resistance and this state is usually associated with obesity and excess body fat.The aim of my thesis was to study the biocommunication between visceral adipose tissue and pancreatic beta-cells during prediabetes and type 2 diabetes, with a focus on two original mediators, isoprostanes and miRNAs. We observed a decrease in isoprostane secretion by peripancreatic adipose tissue during obesity in Zucker fa/fa rats. In this ectopic adipose tissue, this observation may be related to an induction of some antioxidant enzymes and a reduction of the expression of sPLA2 IIA in obese animals. Remarkably, 15-F2t-Isoprostane as well as its epimer used at concentrations of 10 nM and 10 μM inhibited glucose-stimulated insulin secretion in isolated pancreatic islets. This effect could be explained by the binding of isoprostanes to the thromboxane A2 receptor, whose gene and protein expression has been demonstrated for the first time in islets and beta-cells. In Zucker fa/fa rats, less inhibition of insulin secretion through a paracrine biocommunication, could favor beta-cell compensatory mechanisms. Furthermore, the production of miRNAs, contained in extracellular vesicles released by omental adipose tissue, was analyzed in humans by small RNAseq. In obese patients, miRNAs production is altered during insulin resistance and type 2 diabetes with possible consequences for beta-cell function. Differentially expressed miRNAs in type 2 diabetes may participate in its development and represent novel biomarkers and therapeutic targets. In conclusion, this thesis highlighted new biocommunication mechanisms between adipose tissue and beta-pancreatic cells.

CONTEXT: Recent studies have considered the role of inflammation in the development of both cardiovascular disease (CVD) and musculoskeletal conditions, such as rheumatoid arthritis. Studies suggest that inflammation plays a significant role in the development of cardiovascular disease. In conditions of chronic pain, as with rheumatoid arthritis, inflammation has also been noted through elevated levels of inflammatory markers. There are currently no studies that examine the possible connection between inflammatory markers related to increased risk of cardiovascular disease and nonspecific chronic musculoskeletal pain (NCMP). OBJECTIVE: The purpose of this study was to determine whether urinary levels of microalbumin (MA) and F2-isoprostanes (F2-isoPs), inflammatory biomarkers associated with increased CVD risk, are elevated in persons with NCMP compared to nonpain case controls. NCMP refers to pain present for more than 3 days per week and for more than 12 weeks. This type of pain is not due to injury but is associated with interference of normal function. DESIGN: Nonrandomized observational study. METHODS: A cross-sectional study with 120 participants (60 pain subjects, 60 nonpain case-controls). A single first-morning void urine sample was collected from each subject. Urine specific gravity and total volume were measured and then a sample was sent to a lab for analysis of MA and F2-isoPs. Inflammatory biomarker levels in the pain and nonpain groups were compared. RESULTS: There were no significant differences in F2-isoPs levels between the chronic pain group (0.65ng/mg ± 0.05) and the nonpain group (0.80ng/mg ± 0.07) (95% CI (-0.32, 0.03)). However, MA levels were significantly higher in the chronic pain group (2.41mg/g ± 0.24) compared to the nonpain group (1.88mg/g ± 0.14) (95% CI (0.34, 1.68)). MACR levels were also significantly higher in the chronic pain group (2.07mg/g ± 0.31) compared to the nonpain group (1.14mg/g ± 0.14) (95% CI (0.32, 1.64)). CONCLUSION: These findings suggest a possible link between at least one inflammatory marker (microalbumin) and NCMP. This in turn allows for a limited but reasonable inference that NCMP may be a risk factor for cardiovascular disease, mediated through the MA inflammatory biomarker. Further research is needed to more fully understand the possible connection between NCMP and CVD.

<p>Septic shock is frequently seen in intensive care units and is associated with significant mortality. Endotoxin – a major mediator of the pathophysiologic responses – is released during lysis of Gram-negative bacteria. These responses can be mimicked in the endotoxaemic pig.</p><p>This thesis focuses on the following topics: the inflammatory and pathophysiological responses to various endotoxin doses and infusion patterns; covariations between endotoxin induced inflammatory and pathophysiological responses; whether the biological effects of endotoxin can be modulated by clopidogrel and whether tobramycin or ceftazidime reduce plasma cytokine levels.</p><p>Endotoxin induced linear log-log cytokine and F2-isoprostane responses. Leukocyte and platelet responses, pulmonary compliance, circulatory variables as well as indicators of plasma leakage and hypoperfusion exhibited log-linear responses to the endotoxin dose. Biological responses to endotoxaemia such as inflammation, hypotension, hypoperfusion and organ dysfunction were more expressed when the organism was exposed to endotoxin at a higher rate. These results may facilitate the possibility to choose relevant endotoxin administration, when experiments are set up in order to evaluate certain responses to endotoxaemia.</p><p>Correlation studies between cytokines, leukocytes, platelets and the endotoxin dose were in agreement with the well-known ability of endotoxin to induce cytokine expression and to activate both primary haemostasis and leukocytes. Free radical mediated lipid peroxidation and COX-mediated inflammation correlated to cytokine expression and organ dysfunction in endotoxaemic shock. </p><p>Endotoxaemic pigs pretreated with clopidogrel, exhibited a trend towards less expressed deterioration of renal function, although blocking of ADP-induced primary haemostasis is not a key mediator of endotoxin induced deterioration of renal function.</p><p>Tobramycin did not neutralise the biological effects of endotoxin or the plasma levels of endotoxin, suggesting that these antibiotics do not bind to endotoxin.</p><p>Reduction in IL-6 was greater in pigs treated with ceftazidime and tobramycin as compared with those given saline, indicating a possible anti-inflammatory effect of both antibiotics.</p>

Septic shock is frequently seen in intensive care units and is associated with significant mortality. Endotoxin – a major mediator of the pathophysiologic responses – is released during lysis of Gram-negative bacteria. These responses can be mimicked in the endotoxaemic pig. This thesis focuses on the following topics: the inflammatory and pathophysiological responses to various endotoxin doses and infusion patterns; covariations between endotoxin induced inflammatory and pathophysiological responses; whether the biological effects of endotoxin can be modulated by clopidogrel and whether tobramycin or ceftazidime reduce plasma cytokine levels. Endotoxin induced linear log-log cytokine and F2-isoprostane responses. Leukocyte and platelet responses, pulmonary compliance, circulatory variables as well as indicators of plasma leakage and hypoperfusion exhibited log-linear responses to the endotoxin dose. Biological responses to endotoxaemia such as inflammation, hypotension, hypoperfusion and organ dysfunction were more expressed when the organism was exposed to endotoxin at a higher rate. These results may facilitate the possibility to choose relevant endotoxin administration, when experiments are set up in order to evaluate certain responses to endotoxaemia. Correlation studies between cytokines, leukocytes, platelets and the endotoxin dose were in agreement with the well-known ability of endotoxin to induce cytokine expression and to activate both primary haemostasis and leukocytes. Free radical mediated lipid peroxidation and COX-mediated inflammation correlated to cytokine expression and organ dysfunction in endotoxaemic shock. Endotoxaemic pigs pretreated with clopidogrel, exhibited a trend towards less expressed deterioration of renal function, although blocking of ADP-induced primary haemostasis is not a key mediator of endotoxin induced deterioration of renal function. Tobramycin did not neutralise the biological effects of endotoxin or the plasma levels of endotoxin, suggesting that these antibiotics do not bind to endotoxin. Reduction in IL-6 was greater in pigs treated with ceftazidime and tobramycin as compared with those given saline, indicating a possible anti-inflammatory effect of both antibiotics.