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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

COUNTERREGULATORY EFFECTS OF PTX3 ON INFLAMMATION AND CELLULAR AGING

Slusher, Aaron L. 01 January 2018 (has links)
Pentraxin 3 (PTX3) is a vital regulator of innate immune function that has been shown to counterregulate pro-inflammatory signaling and protect against the development of cardiovascular disease (CVD). Less is known about how PTX3 may mitigate against CVD risk by regulating the pro-inflammatory response at the cellular level. Therefore, this dissertation details four manuscripts which aimed to examine the capacity of PTX3 to regulate the innate immune response of peripheral blood mononuclear cells (PBMCs) isolated from healthy adults. Manuscript 1 examined the capacity of PTX3 to alter the inflammatory milieu following in vitro stimulation of isolated PBMCs with the pro-inflammatory lipid palmitate. In addition, Manuscript 2 sought to examine how participation in acute exercise, a powerful anti-inflammatory behavior that reduces CVD risk, alters the inflammatory phenotype and response of mononuclear cells following ex vivo stimulation with lipopolysaccharide (LPS). Manuscript 3 aimed to further elucidate the potential impact of cardiorespiratory fitness on the capacity of PTX3 to stimulate an innate immune response prior to and immediately following acute exercise in aerobically trained and untrained individuals. Finally, Manuscript 4 investigated the impact of healthy aging on plasma PTX3 concentrations and its relationship with telomere length in middle-aged compared to young adults. The capacity of isolated PBMCs to express a key cellular mechanism involved in maintaining longer telomere lengths, human telomerase reverse transcriptase (hTERT), following cellular stimulation with LPS, PTX3, and PTX3+LPS was also examined to address a mechanism that might explain how persistent exposure of circulating immune cells to the age-related pro-inflammatory milieu contributes to the shortening of telomere lengths.
2

Pentraxin 3 in the lung and neutrophils

2013 August 1900 (has links)
Respiratory diseases are a major cause of human morbidity and mortality and are a leading cause of economic loss to livestock producers. The respiratory tract is constantly in contact with dust, bacteria, fungi, viruses and other pathogenic agents that are found in the air. Normally, the body has the ability to clear these foreign particles. However, physiological and environmental stresses can impair airway defense mechanisms resulting in establishment of pulmonary infections. The microbes and their products engage various receptors in the lung to activate epithelium, endothelium, macrophages, neutrophils and other cells. The activation of inflammatory cascade in the lung results in recruitment of neutrophils, damage to air-blood barrier and development of edema. Although there have been significant advances in our understanding of mechanisms of lung inflammation, there have been a lack of any significant advances in the development of new therapeutics to manage lung disease, which may suggest that our understanding of the inflammatory mechanisms is still incomplete. Pentraxin 3 (PTX3) is an innate immune protein which has been implicated in a diverse range of inflammatory processes, such as recruitment of cells and production of cytokines. PTX3 is an acute phase protein, with low or undetectable levels in the circulation of healthy humans and animals, and rapid, dramatic increase in inflammatory diseases. The expression and function of this protein has not been characterized in the lungs of domestic animal species. Because of potential implications of PTX3 in lung inflammation, I studied the expression of PTX3 in normal and inflamed lungs of calves, pigs, horses, foals and humans. Lungs from all of these species showed expression of PTX3 in airway epithelium, alveolar septa, vascular endothelium and inflammatory cells. Western blot performed on homogenates from normal and inflamed lungs from calves and pigs show an increased expression of PTX3 in inflamed lungs (P<0.05). Because protein function is influenced by its location in the cell, I clarified the subcellular expression of PTX3 with immuno-electron microscopy on normal and inflamed calf and horse lungs. PTX3 was localized on pulmonary intravascular macrophages, monocytes, neutrophils and, unexpectedly, platelets. PTX3 was also present in the nuclei of neutrophils, monocytes and pulmonary intravascular macrophages. Neutrophils are critical regulators of acute lung inflammation. Having observed PTX3 in neutrophils, I investigated the effect of E. coli lipopolysaccharide-induced activation on PTX3 in neutrophils in vitro. Neutrophils challenged with E. coli LPS were examined at 30, 60, 90 and 120 minutes after the treatment. Normal peripheral blood neutrophils showed PTX3 expression. Neutrophils activated with LPS appeared ruffled and showed loss of PTX3 expression at 30 minutes followed by recovery of the expression. Western blots performed on normal and activated neutrophil homogenates did not show any differences (P=0.05). Collectively, the data show PTX3 in normal and inflamed lungs across multiple species. PTX3 was also detected in normal and activated neutrophils. While the function of intriguing localization of PTX3 in the nuclei as well as in platelets is not known, the similarity of expression across the species suggest a role for PTX3 in lung inflammation.
3

Envolvimento da pentraxina 3 (PTX3) na patogÃnese da cistite hemorrÃgica induzida por ifosfamida em camundongos / Involvement of pentraxin 3 (PTX3) in the patogenesis of hemorrhagic cystitis induced by iphosphamide in mice

Markus Andret Cavalcante Gifoni 16 February 2008 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A cistite hemorrÃgica (CH) à um fenÃmeno inflamatÃrio frequentemente associado à quimioterapia com oxazafosforinas. Trata-se de uma resposta inflamatÃria inata à aÃÃo da AcroleÃna (ACR), metabÃlito hepÃtico comum à Ifosfamida (IFO) e à ciclofosfamida (CTX). O papel da resposta ao recrutamento de receptores toll-like (TLR) e do estÃmulo por TNF-&#945; e IL-1&#946; com envolvimentto de iNOS e COX-2 tem sido demonstrado neste fenÃmeno. Estudos recentes demonstram que a Pentraxina 3 (PTX3) assume papel de mediador inflamatÃrio em modelos de resposta inflamatÃria inata in vivo, sobretudo relacionada ao recrutamento de TLR. Desta forma, o presente estudo pretende investigar o possÃvel envolvimento de PTX3 na patogÃnese da CH induzida por ifosfamida em camundongos. Para isso, foi realizada quantificaÃÃo de RNAm por RT-PCR para PTX3 e IL-1&#946; em camundongos C57/ BL6 tratados com ifosfamida e salina. Em seguida, o modelo experimental da CH induzida por ifosfamida foi reproduzido em grupos de camundongos com hiperexpressÃo e nocauteados para PTX3 em comparaÃÃo com os respectivos controles do tipo selvagem e com grupos controle tratados com salina para posterior obtenÃÃo dos pesos vesicais Ãmidos (PVU), realizaÃÃo de anÃlise histomorfomÃtrica, imunohistoquÃmica e quantificaÃÃo de RNAm por RT-PCR para PTX3, IL-1&#946;, TNF-&#945; e iNOS. Os animais transgÃnicos e seus controles foram sacrificados com tempos de 3h e 12h apÃs o tratamento, enquanto os nocauteados e seus controles foram sacrificados com 12 horas do tratamento. Finalmente, a CH em animais C57/ BL6 foi modulada com o prÃ-tratamento com Talidomida, Pentoxifilina, MESNA, Amifostina e Aminoguanidina para a posterior marcaÃÃo imunohistoquÃmica com PTX3, IL-1&#946;, TNF-&#945; e iNOS. Observou-se que o RNAm de PTX3 està cerca de 70 vezes mais expresso em animais com CH, contra uma razÃo de expressÃo de 10 para IL-1&#946;. Animais trangÃnicos para PTX3 tÃm reduÃÃo inicial da resposta inflamatÃria com expressÃo inferior de PTX3 e TNF-&#945; e expressÃo aumentada de iNOS e intensificaÃÃo da inflamaÃÃo ao tempo de 12 horas, com expressÃo superior dos mediadores. NÃo houve diferenÃas significativas de intensidade da CH em animais KO em relaÃÃo aos controles. A modulaÃÃo da CH por talidomida e MESNA produziu reduÃÃo importante sobre a expressÃo de PTX3, enquanto a inibiÃÃo da CH por amifostina nÃo teve reduÃÃo expressiva da pentraxina. Em conjunto, estes dados apontam para um envolvimento inequÃvoco de PTX3 na fisiopatologia da inflamaÃÃo inata em modelo de CH murino com Ãntima relaÃÃo coma expressÃo de TNF-&#945; / The Hemorrhagic Cystitis (HC) is an inflammatory reaction usually associated with Cancer Chemotherapy with Oxazaphosphorines. It is an innate inflammatory response to vesical irritation by Acrolein, an hepatic metabolite of the treatment with Iphosphamide and Cyclophosphamide. The role of toll-like receptor (TLR) engagement and TNF-&#945; and IL-1&#946; expression and the involvement of iNOS and COX-2 in the pathogenesis has been well demonstrated in a murine model of HC. Recent data configure pentraxin 3 (PTX3) as an inflammatory mediator in several experimental models of innate immune response in vivo, with a straight relation with TLR engagement. Because of that, this study looks at the involvement of PTX3 in the pathogenesis of iphosphamideâinduced HC in mice. For this purpose, the mRNA to PTX3 and IL-1&#946; t was quantified by RT-PCR in groups of C57BL6 mice treated with Iphosphamide or Saline. After that, groups of transgenic and Knock-Out mice to PTX3 and its respectives wild-type controls were treated with Iphosphamide or saline with intention to measure the Bladder Wet Weight (BWW), histomorphometric scores and Immunohistochemistry and RT-PCR to PTX3, IL-1&#946;, TNF-&#945; e iNOS analysis. The transgenic mice and its controls were killed in 3h and 12h after the treatment, while the PTX3 KO and its controls were killed after 12 hours. Finally, the experimental HC was modulated by pretreatment with Talidomide, Pentoxiphiline, MESNA, Amifostine and Aminoguanidine and the bladders submitted to immunohistochemistry assay (PTX3, TNF-&#945;, IL-1&#946; and iNOS). By RT-PCR quantification, mRNA for PTX3 was expressed 70 times more in mice treated with iphosphamide than in controls, while IL-1&#946; RNAm had an expression rate of 10 times. PTX3 transgenic mice had initial reduction of the inflammatory response with less expression of PTX3 and TNF-&#945; and greater expression of iNOS. In the other hand, after 12 hours, the PTX3 transgenic mice had more inflammatory signs with superior expression of all the mediators. There was no difference between the PTX3 KO mice and its controls in the HC intensity although differences between groups were seen in cytokines expression. Talidomide and MESNA produced substantial reduction on the PTX3 expression, the same was seen to TNF-&#945;, while the amifostine marked inhibition of HC had low effect on PTX3 expression. These data as a whole, point to an unequivocal involvement of PTX3 in the pathogenesis of innate inflammatory response of HC in mice with close relation with TNF-&#945; engagement
4

Structural, biophysical and cellular analysis of synaptic receptors and organizers

Clayton, Amber Jayne January 2013 (has links)
No description available.
5

Evolution of C-Reactive Protein

Pathak, Asmita, Agrawal, Alok 01 January 2019 (has links)
C-reactive protein (CRP) is an evolutionarily conserved protein. From arthropods to humans, CRP has been found in every organism where the presence of CRP has been sought. Human CRP is a pentamer made up of five identical subunits which binds to phosphocholine (PCh) in a Ca2+-dependent manner. In various species, we define a protein as CRP if it has any two of the following three characteristics: First, it is a cyclic oligomer of almost identical subunits of molecular weight 20–30 kDa. Second, it binds to PCh in a Ca2+-dependent manner. Third, it exhibits immunological cross-reactivity with human CRP. In the arthropod horseshoe crab, CRP is a constitutively expressed protein, while in humans, CRP is an acute phase plasma protein and a component of the acute phase response. As the nature of CRP gene expression evolved from a constitutively expressed protein in arthropods to an acute phase protein in humans, the definition of CRP became distinctive. In humans, CRP can be distinguished from other homologous proteins such as serum amyloid P, but this is not the case for most other vertebrates and invertebrates. Literature indicates that the binding ability of CRP to PCh is less relevant than its binding to other ligands. Human CRP displays structure-based ligand-binding specificities, but it is not known if that is true for invertebrate CRP. During evolution, changes in the intrachain disulfide and interchain disulfide bonds and changes in the glycosylation status of CRP may be responsible for different structure-function relationships of CRP in various species. More studies of invertebrate CRP are needed to understand the reasons behind such evolution of CRP. Also, CRP evolved as a component of and along with the development of the immune system. It is important to understand the biology of ancient CRP molecules because the knowledge could be useful for immunodeficient individuals.
6

MECHANISMS OF NEURODEGENERATION IN A MOUSE MODEL OF SANDHOFF DISEASE: ROLES OF INFLAMMATION, EXCITOTOXICITY, AND APOPTOSIS / MECHANISMS OF NEURODEGENERATION IN A MOUSE MODEL OF SANDHOFF DISEASE

Hooper, Alexander William Maurice January 2016 (has links)
Lysosomal storage disorders are a group of rare neurodegenerative diseases that are collectively common, sharing many aspects with other neurodegenerative disorders, including substrate build-up and neuroinflammation. The GM2 Gangliosidoses, Tay-Sachs disease and Sandhoff disease, are pathologically overlapping lysosomal storage disorders, with high prevalence within specific ethnicities. Their effects are neurologically devastating and often fatal at young ages. Current treatments only slow or stall an inevitable decline in health. Novel treatment targets are needed for these disorders, and others with similar pathologies. In these works we demonstrate the negative effect the inflammatory cytokine tumour necrosis factor-alpha has on survival of a model of Sandhoff disease. We demonstrate its role in the upregulation of astrogliosis, and apoptosis, and we present evidence that this effect on astrogliosis occurs through an upregulation of the JAK-2/STAT3 pathway. Though fruitful, a singular focus on inflammation/gliosis in these diseases has left a vacuum in the research into neuron specific molecular processes. We observe the development of inflammation, astrogliosis and neuronal processes in our model, and demonstrate a bi-phasic disease progression, in which early onset microgliosis precedes terminal astrogliosis, apoptosis, and a decline in excitatory glutamate receptors, suggesting neuron-specific malfunction. Furthermore, we show that knockout of the synaptic protein neuronal pentraxin 1 retards neurodegeneration and extends the lifespan of Sandhoff disease mice, independent of inflammation or astrogliosis. Through electrophysiology, we provide evidence of dysregulation of glutamate receptors in Sandhoff disease, and show that knockout of neuronal pentraxin 1 provides rescue from this dysregulation. This work expands on research into gliosis in GM2 gangliosidoses, presents the finding of a novel protein isoform, and presents a new focus on non-glial disease mechanisms and treatments for these and other neurodegenerative disorders. / Thesis / Doctor of Philosophy (PhD) / Lysosomal storage disorders are a group of neurological diseases that are debilitating, and often fatal at a young age. Two diseases of this group- Tay-Sachs disease and Sandhoff disease – are similar in their causes and symptoms. Current treatments for these diseases only slow or stall an inevitable decline in health. New targets for treatment are required, and we provide data suggesting several proteins that may fit this criterion. We also provide evidence of the discovery of a new form of one of these proteins, which is found in high levels in the disease, indicating it may be important in these and other neurodegenerative diseases. Finally, we provide findings indicating that a certain cell type, which is largely ignored in current research for these diseases, may be important in the disease progress. These findings increase our knowledge of Tay-Sachs disease and Sandhoff disease, and open new avenues for medicinal intervention.
7

Proteasome subunit deficiency influences the innate immune response to Streptococcus pneumoniae

Kirschner, Felicia Claudia 19 January 2016 (has links)
Proteasomen, die die proteolytisch aktiven Untereinheiten LMP7, LMP2 und MECL1 inkorporieren, nennt man Immunoproteasomen. Während einer Immunreaktion führen diese regulierende sowie modulierende Funktionenaus. Sie sind konstitutiv exprimiert in Zellen hämatopoetischen Ursprungs, ein Bestandteil des angeborenen Immunsystems, die die erste Angriffsfront gegen pathogene Mikroorganismen ausbilden. Um die Bedeutung des Immunoproteasoms für die angeborene Immunantwort bei einer Streptococcus pneumoniae Infektion auf zu zeigen, charakterisierten wir den Krankheitsverlauf einer bakteriellen Pneumonie und analysierten lokale aber auch systemische Immunreaktionen in LMP7 ko Mäusen mit Hilfe eines S. pneumoniae Infektionsmodels. Die hier generierten Daten zeigten einen fortgeschrittenen Krankheitsverlauf in LMP7 ko Mäuse, der in einer systemischen inflammatorischen Immunreaktion endete und sich in klinischen Parametern, wie physiologische Kondition, spezifische diagnostische Marker und Immunsuppression, andeutete. Der Zustand der Sepsis entwickelte sich vermutlich aufgrund einer erhöhten bakteriellen Last im Blut und führte zu einer vorzeitigen Mortalität infizierter LMP7 ko Tiere. Obwohl die Fähigkeit von LMP7 ko Leukozyten ex vivo Bakterien zu eliminieren nicht beeinträchtigt war, zeigten LMP7 ko Mäuse in vivo eine verminderte Genexpression immunmodulierender Moleküle, wie Pentraxine, Fikoline und Kollektine. Diese Moleküle fördern die Aufnahme, Elimination und Degradation pathogener Mikroorganismen. Die reduzierte Expression opsonierender Moleküle wurde begleitet von einer veränderten proteasomalen Zusammensetzung in murinen Makrophagen und Lebergewebe. Zusammengefasst lässt sich sagen, dass diese Ergebnisse eine bisher unbekannte Rolle von Immunoproteasomalen Untereinheiten bei der Regulierung der angeborenen Immunantwort auf extrazelluläre bakterielle Infektionen unterstreichen. / Immunoproteasomes, harboring the active site subunits LMP7, LMP2, and MECL1 exert protective, regulatory or modulating functions during infection-induced immune responses. Immunoproteasomes are constitutively expressed in hematopoietic derived cells, constituting the first line of defense against invading pathogens. To clarify the impact of immunoproteasomes on the innate immune response against Streptococcus pneumoniae, we characterized the progression of disease and analyzed the local as well as systemic innate immune response in LMP7 ko mice by using a S. pneumoniae infection model. Data showed that mice deficient in LMP7 suffered from a more severe case of pneumonia which ended in a systemic inflammatory response indicated by aggravated clinical signs, diagnostic parameters, and immune suppression. The systemic inflammatory response probably established in consequence of an increased bacteremia and resulted in early mortality. Although, bacterial killing efficiency of LMP7 ko leukocytes was unaffected ex vivo, LMP7 ko mice exhibited a reduction in the transcription of genes encoding immune modulating molecules such as pentraxins, ficolins, and collectins, which facilitate opsonophagocytosis. The reduced expression of opsonins was accompanied by an affected subunit composition of proteasomes in murine macrophages and liver. In summary these results highlight an unsuspected role for immuno-subunits in modulating the innate immune response to extracellular bacterial infections.
8

Oxidative Stress, Angiogenesis and Inflammation in Normal Pregnancy and Postpartum

Palm, Maria January 2012 (has links)
The aims were to investigate oxidative stress (I), angiogenesis (II) and inflammation (III-IV) in healthy women during pregnancy and postpartum. Oxidative stress was estimated by measurement of 8-iso-PGF2α and the antioxidants α- and γ-tocopherol. The angiogenic factors PlGF, VEGF-A and the antiangiogenic factor sFlt1 were measured to estimate angiogenesis. PTX3, IL-6, TNF-α and a PGF2α metabolite were measured to estimate inflammation. Out of 52 included women, 15 had minor pregnancy complications and 37 were classified as normal. In study III data from all 52 women were used. For the other studies (I, II and IV) only data from the 37 women with normal pregnancy were used. Pregnancy was associated with increased levels of 8-iso-PGF2α with advancing gestational age. The median postpartum value corresponded to values observed in early gestation and a significant decrease was observed from late pregnancy to postpartum. Lipid-adjusted α- and γ-tocopherol levels decreased with advancing gestational age (I). PlGF increased from early pregnancy until weeks 29–30 and thereafter decreased until week 40. sFlt1 levels were relatively constant until weeks 29–30, when they increased, reaching a peak at weeks 39–40. Postpartum levels were low. The sFlt1:PlGF ratio decreased from weeks 9–12, was constantly low from weeks 19–20 to 37–38 and then increased to weeks 39–40. VEGF-A was detectable in only 8 % of the samples during pregnancy and in 64 % postpartum (II). There was a continuous increase of PTX3 as pregnancy progressed. The increase was most evident after week 31 with the highest levels just before delivery (III). IL-6 increased throughout pregnancy and remained high postpartum. No change in TNF-α could be seen with advancing gestational age or postpartum. The PGF2α metabolite levels increased throughout pregnancy and decreased postpartum (IV). In conclusion, normal pregnancy is associated with mild oxidative stress and inflammation. This might have physiological effects for normal pregnancy development. By delineating how these mediators of oxidative stress, angiogenesis and inflammation fluctuate throughout normal pregnancy and postpartum, we have established a reference for studies of these factors in pregnancy complications.
9

Characterization of proteins found in serum and sputum samples from ventilator associated pneumonia patients

Yenuga, Hima Priya 29 May 2020 (has links)
No description available.
10

Estudo do efeito do inibidor da enzima adenosina desaminase, EHNA, sobre a enterite induzida pela toxina a do Clostridium difficile em alÃa ileal isolada de camundongos / The effect of the adenosine deaminase inhibitor, EHNA, on Clostridium difficile toxin-A-induced enteritis in murine ileal loops

Ana FlÃvia Torquato de AraÃjo Junqueira 06 June 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O Clostridium difficile tem como principal fator de virulÃncia a toxina A (TxA), a qual provoca inflamaÃÃo e destruiÃÃo tecidual aguda em intestinos de animais experimentais e de pacientes com a doenÃa induzida por esta bactÃria. Em locais de injÃria tecidual, adenosina à produzida em altas concentraÃÃes, onde exerce uma sÃrie de efeitos antiinflamatÃrios, limitados por sua rÃpida degradaÃÃo pela enzima adenosina desaminase. O objetivo deste trabalho foi investigar o efeito da inibiÃÃo da enzima adenosina desaminase pelo EHNA (eritro-9-(2-hidrÃxi-3-nonil)-adenina) sobre a enterite induzida pela TxA do C. difficile em alÃa ileal de camundongos. Para isto, injetamos EHNA (90 &#956;mol/kg) ou PBS i.p. 30 minutos antes da administraÃÃo de TxA (10 a 100 &#956;g) ou PBS na alÃa ileal isolada. Os animais foram sacrificados 3 horas depois da induÃÃo da enterite e as alÃas foram retiradas para estudo. As razÃes peso/comprimento da alÃa e volume de secreÃÃo/comprimento da alÃa foram calculadas e amostras de tecido foram coletadas para histopatologia, dosagem de atividade de mieloperoxidase (MPO), dosagem de TNF-&#945;, IL-1&#946; e IL-10 por ELISA, imunohistoquÃmica para TNF-&#945;, IL-1&#946;, NOS induzÃvel e PTX3, e PCR para TNF-&#945;, IL-1&#946; e PTX3. A injeÃÃo de TxA (10 a 100 &#956;g) nas alÃas ileais aumentou significativamente (p<0,05) as razÃes peso/comprimento da alÃa e volume de secreÃÃo/comprimento da alÃa com resultados consistentes a partir de 50 &#956;g. A TxA promoveu significativa (p<0,05) destruiÃÃo tecidual, edema, infiltraÃÃo de cÃlulas inflamatÃrias, aumento das citocinas TNF-&#945; e IL-1&#946;, e elevaÃÃo de iNOS e PTX3. Todos esses parÃmetros foram significativamente revertidos com o uso do EHNA (p<0,05). Em adiÃÃo, a TxA nÃo alterou os nÃveis de IL-10 em relaÃÃo ao controle, mas o prÃ-tratamento com EHNA promoveu uma elevaÃÃo nos nÃveis desta citocina. Assim, concluÃmos que na enterite induzida pela TxA em camundongos o EHNA demonstrou um potente efeito antiinflamatÃrio, reduzindo consideravelmente a lesÃo tecidual, a migraÃÃo neutrofÃlica, a expressÃo e os nÃveis de citocinas prÃinflamatÃrias (TNF-&#945;, IL-1&#946;) e produzindo um aumento nos nÃveis de IL-10. AlÃm disso, a administraÃÃo de TxA induziu um aumento na expressÃo da proteÃna PTX3 e no nÃmero de cÃlulas imunomarcadas para iNOS no tecido ileal, ambos revertidos pelo EHNA / The main factor of virulence in Clostridium difficile is toxin A (TxA), which can induce inflammation and acute tissue injury in the bowels of animals and humans affected by this organism. The high concentration of adenosine generated upon injury produces a number of antiinflammatory effects limited by rapid degradation by adenosine deaminase. The objective of this study was to determine the effect of EHNA (erythro-9-(2-hydroxy-3-nonyl)-adenine) inhibition of adenosine deaminase upon TxA-induced ileal loop enteritis in mice. EHNA (90 &#956;mol/kg) or PBS was injected i.p. 30 minutes prior to TxA (10-100 &#956;g) or PBS instillation into the ligated ileal loop. The animals were euthanized 3 hours after enteritis induction and the ileal loops were retrieved for analysis. The weight/length ratio and the secretion volume/length ratio were calculated and tissue samples were submitted to histopathological study, myeloperoxidase assay (MPO), measurement of TNF-&#945;, IL-1&#946; and IL-10 levels with ELISA, immunohistochemical tests for TNF-&#945;, IL-1&#946;, inducible NOS and PTX3, and PCR assay for TNF-&#945;, IL-1&#946; and PTX3. The instillation of TxA (10-100 &#956;g) into the ileal loop significantly increased (p<0.05) the weight/length ratio and the secretion volume/length ratio with consistent results above 50 &#956;g. TxA induced a significant amount (p<0.05) of histological damage, edema and inflammatory cell infiltration and increased the production of TNF-&#945;, IL-1&#946;, iNOS and PTX3. All changes were significantly reverted by treatment with EHNA (p<0.05). Moreover, IL-10 levels remained unchanged in animals treated with TxA, but increased in animals receiving EHNA. In conclusion, in mice with TxA-induced enteritis EHNA produced considerable antiinflammatory effects, reducing tissue injury, neutrophil migration, the expression and levels of proinflammatory cytokines (TNF-&#945; and IL-1&#946;) and producing an increase in IL-10 levels. In addition, TxA instillation increased PTX3 expression and the number of cells immunolabeled for iNOS in the ileal tissue, both of which were reverted by EHNA

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