Dairy cows are increasingly predisposed to diseases in the periparturient time period due in part to immunosuppression. Dystocia amplifies the disease risk due to the increased tissue trauma and stress the animal endures during the lengthened parturition. To decrease the increased inflammatory response seen in dystocic animals and improve their well-being in the postpartum period, we administered either a potent steroid, dexamethasone (DEX), or a saline control (CON) to cows within 12 hours after a dystocic parturition. The inflammatory marker haptoglobin was measured as well as behavioral and production measures. We observed that primiparous DEX cows exhibited a greater haptoglobin concentration on d 3 and d 7 postpartum compared to primiparous CON cows. Behavior was seen to be altered between the treatments, with DEX cows having reduced locomotion and increased lying times in the week following parturition. These measures could indicate pain reduction, suggesting improved comfort. Milk yield was affected, with a reduction of 7.3 kg/d in multiparous DEX cows in comparison to CON cows for almost the entirety of the first month following dexamethasone treatment. No treatment effects were seen for milk production of primiparous cows. Additional research is needed for further investigation of the immunological and production effects of steroids on postpartum dairy cows, especially between parities. / Master of Science in Life Sciences / Dairy cows are most likely to develop metabolic diseases in the weeks leading up and following calving. This risk can be heightened in cows that experience a difficult calving process, most likely due to an increased inflammatory response. A potent steroid, dexamethasone, was assessed after a difficult calving to see if postpartum animal recovery is accelerated through dampening of the inflammatory response. Dairy cows were given either dexamethasone (DEX) or saline control (CON) within 12 hours after a difficult birth to counter the inflammatory response. Our study found that primiparous cows that received dexamethasone, exhibited a greater concentration of the inflammatory marker, haptoglobin, on d 3 and d 7 postpartum than in CON cows. This may be attributed to increased tissue trauma in first time calvings since there was no treatment difference in multiparous cows. Cows that received dexamethasone also had a reduction in locomotion and an increased amount of total lying time in the days following calving. Additionally, multiparous cows that received dexamethasone exhibited a reduction in milk production by 7.3 kg/d for almost the entirety of the first month following treatment. Future research needs to examine the long-term effects of dexamethasone on the mammary gland and the inflammatory response in different parity cows postpartum.

Master of Science / Department of Clinical Sciences / Elizabeth G. Davis / Objective: To determine pharmacokinetic and pharmacodynamic properties of oral dexamethasone solution and powder compared to intravenous dexamethasone solution in healthy horses. Animals: 6 horses, 13-27 years if age, 385-630 kg Procedures: In a randomized, cross-over block design six healthy adult horses each received the following treatments 1) dexamethasone solution IV 0.05 mg/kg, 2) dexamethasone solution orally (PO) 0.05 mg/kg, and 3) dexamethasone powder PO 0.05 mg/kg all in the fed and fasted state. Each horse acted as an untreated control as secretion of cortisol was monitored for normal circadian rhythm. Quantification of plasma dexamethasone concentration and serum cortisol activity was determined by LC/MS and chemiluminescent enzyme immunoassay, respectively. Results: Each horse exhibited a circadian rhythm in cortisol secretion; however there was variation present between each horse. Mean cortisol concentrations at 6:00 AM and 8:00 AM were significantly higher than concentrations at 8:00 PM and 10:00PM. Cortisol concentrations were significantly less than base-line starting 1 hour post-administration of dexamethasone through 72 hours for the fasted treatment groups, and 2 hours through 48 hours for the fed groups. Pharmacokinetic modeling resulted in a two compartment model for the IV administration with elimination from the central compartment, and a one compartment model for orally administered dexamethasone. Oral, fasted, compounded powder achieved a significantly higher maximum concentration (Cmax) than both fasted and fed oral dexamethasone solutions. The AUC0inf for the orally administered compounded powder was significantly different when comparing fasted versus fed treatment groups. Bioavailability ranged between 33% and 70% among treatment groups, but due to the high variability there was not a significant difference. Conclusions and Clinical Relevance: Hospitalization of the horses did not have an effect on their circadian rhythm of cortisol secretion. Oral and intravenous administration of dexamethasone resulted in adrenal suppression with cortisol concentrations returning to base-line 48-72 hours post-administration. Although bioavailability was variable cortisol suppression was similar among all treatment groups. The variability in oral absorption will need to be taken in to account for oral dosing of dexamethasone.

Der epitheliale Natriumtransport in der postnatalen Lunge ist für einen ausgeglichenen Flüssigkeitstransport und eine gesunde Lungenfunktion unabdingbar. Eine bedeutende Rolle spielt hierbei der epitheliale Natriumkanal (ENaC). Es ist bereits bekannt, dass unter dem Einfluss von weiblichen Sexualhormonen, wie Progesteron, oder durch die Substitution von Glukokortikoiden, wie Dexamethason, die mRNA-Expression des ENaC und dessen elektrophysiologische Aktivität erhöht wird. Zur Lungenreifeinduktion werden bei Frühgeburtlichkeitsbestrebungen hohe Dosen von Glukokortikoiden verabreicht, die im fetalen Kreislauf auf hohe Progesteronkonzentrationen treffen. Die Auswirkung dieser Hormonkombination auf den epithelialen Natriumtransport ist bisher unbekannt. Um dieser Frage nachzugehen, wurden alveoläre Epithelzellen von Rattenfeten auf permeablen Membranen gezüchtet und mit unterschiedlichen Konzentrationen von Progesteron und Dexamethason inkubiert. Anschließend wurde die mRNA-Expression der drei Untereinheiten des ENaC (α, β, γ) mittels Real-Time PCR analysiert. Mit Hilfe von Ussing-Kammer Messungen wurden die Einflüsse auf den epithelialen Natriumtransport ermittelt. Durch die Experimente konnte der stimulierende Einfluss beider Hormone auf die mRNA-Expression bestätigt werden, wobei Dexamethason einen deutlich stärkeren Effekt erreichte. Durch die Kombination beider Hormone kam es zu einer signifikant geringeren mRNA-Expression und einem verminderten funktionellen Natriumtransport im Vergleich zur reinen Dexamethasoninkubation. Der Einsatz von Hormonrezeptor-Antagonisten zeigte, dass eine Blockierung des Progesteronrezeptors die mRNA-Expression erhöhte, wohingegen die Hemmung des Glukokortikoidrezeptors die mRNA-Expression der ENaCUntereinheiten verminderte. Zusammenfassend zeigen die Ergebnisse, dass Glukokortikoide und weibliche Geschlechtshormone, die einzeln zur Erhöhung der Natriumabsorption führen, durch die Kombination beider Hormone ihren Einfluss auf den Natriumtransport reduzieren.

Dexamethasone has been shown to inhibit IgE-mediated mast cell activation, and the present research investigated its role in suppressing IL-33-mediated mast cell activation. We have found that micromolar concentrations of Dexamethasone are capable of suppressing IL-33-mediated mast cell cytokine production, on several genetic backgrounds, and in not only bone marrow derived mast cells, but also peritoneal mast cells. Intracellular staining demonstrated that Dexamethasone significantly reduces expression of the IL-33 receptor, T1/ST2, in mast cells; however, the cytokine suppression is independent of T1/ST2 downregulation. At the same time, Dexamethasone pretreatment significantly reduced ERK phosphorylation, but our data suggests that inhibition occurs even prior to ERK blockade. Finally, Dexamethasone treatment in vivo reduced IL-33-mediated cytokine production and neutrophil infiltration in the murine peritoneum. Thus, Dexamethasone, a well-established therapy for inflammatory disease, can suppress IL-33-mediated mast cell activation, and may therefore be effective for treating diseases now being attributed to IL-33 effects.

As estrongiloidíases são parasitoses intestinais causadas por várias espécies do gênero Strongyloides e apresentam distribuição cosmopolita. O objetivo deste estudo foi investigar a interferência do tratamento diário com dexametasona no ciclo pulmonar durante a infecção por Strongyloides venezuelensis em ratos. Investigamos o efeito do tratamento com glicocorticóides na migração de eosinófilos, mastócitos e macrófagos no parênquima pulmonar. Demonstramos ainda, como os efeitos do tratamento diário com a dexametasona atuam na formação do granulomas. Três principais aspectos foram encontrados: 1) Aumento da inflamação hemorrágica, provocado pela passagem das larvas para o espaço alveolar; 2) Significante redução da migração de eosinófilos e mastócitos no eixo axial pulmonar e, 3) Interferência crucial na migração de eosinófilos para os focos de passagem das larvas e, conseqüente, impedimento da organização do granuloma, sugerindo que a formação da rede de fibras reticulares deve ter um papel crucial no aprisionamento do parasita, favorecendo um melhor desempenho das células inflamatórias na eliminação do mesmo. Este trabalho mostrou que o uso de drogas com ação imuno-modulatória, tais como a dexametasona, pode interferir na morbidade no ciclo pulmonar durante a infecção por S. venezuelensis, contribuindo para revelar os mecanismos envolvidos na sua patogênese. / The aim of this study was investigate the interference of dexamethasone treatment in the pulmonary cycle of Strongyloides venezuelensis infection in rats. The immunomodulatory effects on the inflammatory process generated by the passage of the larvae into pulmonary parenchyma during their migration were analyzed. Three principal effects were found: 1) Increased alveolar hemorrhagic inflammation provoked by the passage of larvae into the alveolar spaces; 2) Significant decrease of eosinophil and mast cell migration to the axial septum of the lungs and 3) Impaired eosinophil migration to the parasite foci and deficient formation of the reticular fiber network, interfering with the granuloma organization. This study demonstrated that the use of drugs with immunomodulatory actions, such as dexamethasone, in addition to interfere with the morbidity from the pulmonary cycle of S. venezuelensis infection, can contribute to reveal the mechanisms involved in its pathogenesis.

O estudo investigou a influência do fator de transformação de crescimento beta1 (TGFb1) sobre células osteogênicas induzidas com fatores mineralizantes (dexametasona Dex), comparando a viabilidade e a proliferação celular, a mineralização, e a expressão de proteínas não colágenas da matriz osteopontina (OPN), sialoproteína óssea (BSP) e fibronectina (FN). A morfologia foi examinada por microscopia eletrônica de transmissão (MET). O TGFb1 diminuiu a viabilidade e a proliferação celular, mesmo com Dex. A mineralização da matriz foi positivo apenas no grupo tratado com Dex, e negativo nos grupos tratados TGFb1 e TGFb1+Dex. OPN e BSP não foram imunoreativas apenas para o controle negativo, já a FN foi imunoexpressa em todos os grupos. A mineralização foi confirmada, tanto no controle positivo quanto no tratado com Dex, e alterações morfológicas foram observadas nas células tratadas com TGFb1 e TGFb1+Dex, através da MET. Esse estudo mostrou que TGFb1 inibe a mineralização, alterando a viabilidade e proliferação, bem como a morfologia celular, mesmo quando tratadas com Dex. / The study investigated the influence of transforming growth factor beta1 (TGFb1) on osteogenic cells induced with mineralizing factors (dexamethasone Dex), comparing the viability and proliferation cellular, the formation of mineral nodules in vitro, and the expression of the noncollagenous matrix proteins osteopontin (OPN), bone sialoprotein (BSP), and fibronectin (FN). The morphology was examined by transmission electron microscopy (TEM). The TGFb1 decreased the viability and proliferation cellular, even when combined with Dex. The mineralization of matrix was positive only in the group treated with Dex, and negative in the groups treated with TGFb1 and TGFb1+Dex. OPN and BSP were not immunoreactive only negative, already the FN was immunoreactive in all groups.The mineralizing was confirmed in the positive control and Dex, through TEM. Some morphological changes were seen in cells treated with TGFb1 and TGFb1+Dex. This study showed that TGFb1 inhibits the mineralization, changing the viability, proliferation and cell morphology, even when treated with Dex.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / IntroduÃÃo: A mucosite induzida por antineoplÃsicos à um fator limitante na terapia anticÃncer. Mucosite à um termo clÃnico que descreve uma sÃndrome caracterizada por reaÃÃo inflamatÃria da mucosa de todo o trato digestivo com ulceraÃÃes. A mucosite intestinal por antineoplÃsicos desencadeia alteraÃÃes da motilidade digestiva. A dexametasona à um glicocorticÃide cujo principal efeito farmacolÃgico decorre de sua aÃÃo antiinflamatÃria e imunossupressora Objetivos: Investigar a dismotilidade gastrintestinal associada à mucosite intestinal induzida por irinotecano em camundongos, bem como avaliar o efeito da modulaÃÃo farmacolÃgica da resposta inflamatÃria sobre estas alteraÃÃes motoras. MÃtodos: Camundongos Swiss machos (20â25g) foram tratados do D1-D4 com irinotecano (75 mg/Kg, i.p.) ou com salina (0,1ml, i.p.), o sacrificio foi realizado no sÃtimo dia experimental. Afim de estudar alteraÃÃes relacionadas à mucosite intestinal, amostras do duodeno, jejuno e Ãleo, foram removidas para avaliar a injÃria epitelial por morfometria, escores histolÃgicos, e atividade de MPO, tendo a diarrÃia sido avaliada antes do sacrifÃcio. Para avaliaÃÃo de citocinas amostras de duodeno foram retiradas e pelo mÃtodo de ELISA foi determinada a concentraÃÃo de TNF-, IL-1, KC e IL-10. Para avaliar a motilidade digestiva, os animais foram deixados em jejum de 18 horas do D6 para o D7. No D7, foram administrados 350ÂL da soluÃÃo glicosada (5%) contendo vermelho de fenol (VF) a 0,75 mg/ml em cada animal antes do sacrifÃcio. ApÃs os tempos de 10, 20 e 30 min, os animais foram sacrificados e submetidos a uma laparotomia mediana, sendo o estÃmago retirado completamente e o intestino delgado divido em 3 partes iguais: proximal, medial e distal. A seguir o esvaziamento gÃstrico, trÃnsito intestinal e transito gastrintestinal (centro geomÃtrico) foram determinados por espectofotometria. A seguir, em outro grupo experimental, foi avaliado se a modulaÃÃo farmacolÃgica do processo inflamatÃrio poderia reverter Ãs alteraÃÃes da motilidade digestiva associadas à mucosite por irinotecano. Para tanto, dexametasona (2,5mg/kgm s.c.) ou metoclopramida (10mg/kg i.p.) do D1-D7, foram administradas 30 minutos antes da administraÃÃo de irinotecano. A seguir foram avaliados todos os parÃmetros descritos acima. Resultados: O tratamento com irinotecano foi capaz de induzir uma lesÃo intestinal com um importante comprometimento da barreira epitelial funcional com a presenÃa das seguintes alteraÃÃes: diarrÃia, leucopenia, encurtamento acentuado das vilosidades intestinais, necrose parcial de criptas, aumento da atividade de MPO, aumento na concentraÃÃo de KC e IL-1 e retarde do esvaziamento gÃstrico e transito gastrontestinal e aceleraÃÃo do transito intestinal. O tratamento com dexametasona, mas nÃo metoclopramida, reduziu significativamente as lesÃes intestinais, com recuperaÃÃo da altura dos vilos, da profundidade das criptas, diminuiÃÃo da atividade de MPO, reduÃÃo da concentraÃÃo de IL-1. Ademais, somente o tratamento com dexametasona, mas nÃo por metoclopramida, foi capaz de reverter retarde do esvaziamento gÃstrico, bem como a aceleraÃÃo do trÃnsito gastrintestinal. ConclusÃo: A mucosite intestinal induzida por irinotecano foi capaz de causar dismotilidade e resposta inflamatÃria gastrintestinal com participaÃÃo de KC e IL1 a qual se associa com o retarde do esvaziamento gÃstrico e trÃnsito gastrintestinal e aceleraÃÃo do trÃnsito intestinal. ConcluÃmos ainda que a dexametasona, mas nÃo metoclopramida, reduziu a resposta inflamatÃria e modulou parcialmente a dismotilidade gastrintestinal associada à mucosite por iriniotecano. / Introduction: Mucositis induced by antineoplasic drugs is a limiting factor in anticancer therapy. Mucositis is a clinical term which describes a syndrome characterized by mucosal ulceration of the entire digestive tract. Mucositis results from intestinal inflammatory events, which induces changes in gastrointestinal motility. Dexamethasone is a glucocorticoid whose main pharmacological effect is anti-inflammatory and immunosuppressive. Objectives: To investigate the gastrointestinal dismotility associated with irinotecan-induced intestinal mucositis in mice and to assess the effect of pharmacological modulation of the inflammatory response on these motor abnormalities. Methods: Swiss male mice (20-25g) were treated in the D1-D4 with irinotecan (75 mg / kg, ip) or saline (0.1 ml, ip), the sacrifice was performed on the seventh day trial in order to study changes related to intestinal mucositis. Samples of duodenum, jejunum and ileum were removed to assess the epithelial injury by morphometry, histological scores and MPO activity, and diarrhea were evaluated before sacrifice. For evaluation of cytokine samples of duodenum were removed and the ELISA was determined concentrations of TNF-, IL-1 , KC and IL-10. In order to evaluate gastrointestinal motility, the animals were kept fasting for 18 hours from D6 to D7. In D7, were administered 350μL of glucose solution (5%) containing phenol red (VF) to 0.75 mg / ml in each animal prior to sacrifice. After the times of 10, 20 and 30min, animals were sacrifice. Stomach was totally removed, and small intestine was divided into 3 parts: proximal, medial and distal. The gastric emptying, intestinal transit and gastrointestinal transit were determinate by spectrofotometry. In other experimental group, we evaluated if pharmacological modulation of the inflammatory process could reverse the gastrointestinal dismotility associated with irinotecan- induced intestinal mucositis. Then, dexamethasone (2.5 mg / kg sc) or metoclopramide (10mg/kg ip) of D1-D7 were administrated 30 minutes before irinotecan administration and all of parameters described before were evaluated Results: Treatment with irinotecan was able to induce an intestinal lesion with significant impairment of epithelial barrier function in the presence of the following changes: diarrhea, leukopenia, marked shortening of the villus, crypts of partial necrosis, increase im MPO activity, increased concentrations of IL-1  and changes in gastrointestinal motility. Treatment with dexamethasone, but not with metoclopramide, significantly reduced the intestinal lesions, with recovery of villous height, crypt depth, decreased MPO activity, reduced concentrations of IL-1. In addition, dexamethasone, but not metoclopramide, was able to reverse the delay in gastric emptying and increase in intestinal transit. Conclusion: The intestinal mucositis induced by irinotecan was able to cause gastrointestinal dismotility and inflammatory response with the participation of KC and IL1 which is associated with delay gastric emptying and gastrointestinal transit and acceleration of intestinal transit. It is also concluded that dexamethasone, but not metoclopramide, reduced the inflammatory response and modulated in part the gastrointestinal dismotility associated with irinotecan-induced intestinal mucositis.

As estrongiloidíases são parasitoses intestinais causadas por várias espécies do gênero Strongyloides e apresentam distribuição cosmopolita. O objetivo deste estudo foi investigar a interferência do tratamento diário com dexametasona no ciclo pulmonar durante a infecção por Strongyloides venezuelensis em ratos. Investigamos o efeito do tratamento com glicocorticóides na migração de eosinófilos, mastócitos e macrófagos no parênquima pulmonar. Demonstramos ainda, como os efeitos do tratamento diário com a dexametasona atuam na formação do granulomas. Três principais aspectos foram encontrados: 1) Aumento da inflamação hemorrágica, provocado pela passagem das larvas para o espaço alveolar; 2) Significante redução da migração de eosinófilos e mastócitos no eixo axial pulmonar e, 3) Interferência crucial na migração de eosinófilos para os focos de passagem das larvas e, conseqüente, impedimento da organização do granuloma, sugerindo que a formação da rede de fibras reticulares deve ter um papel crucial no aprisionamento do parasita, favorecendo um melhor desempenho das células inflamatórias na eliminação do mesmo. Este trabalho mostrou que o uso de drogas com ação imuno-modulatória, tais como a dexametasona, pode interferir na morbidade no ciclo pulmonar durante a infecção por S. venezuelensis, contribuindo para revelar os mecanismos envolvidos na sua patogênese. / The aim of this study was investigate the interference of dexamethasone treatment in the pulmonary cycle of Strongyloides venezuelensis infection in rats. The immunomodulatory effects on the inflammatory process generated by the passage of the larvae into pulmonary parenchyma during their migration were analyzed. Three principal effects were found: 1) Increased alveolar hemorrhagic inflammation provoked by the passage of larvae into the alveolar spaces; 2) Significant decrease of eosinophil and mast cell migration to the axial septum of the lungs and 3) Impaired eosinophil migration to the parasite foci and deficient formation of the reticular fiber network, interfering with the granuloma organization. This study demonstrated that the use of drugs with immunomodulatory actions, such as dexamethasone, in addition to interfere with the morbidity from the pulmonary cycle of S. venezuelensis infection, can contribute to reveal the mechanisms involved in its pathogenesis.

Alzheimers disease (AD) is pathologically characterized by amyloid plaques, neurofibrillary tangles, inflammation, and neurodegeneration. According to the amyloid hypothesis of AD, the central mediating event of the disease is the deposition of amyloid. The inflammation hypothesis of AD states that it is the inflammatory response to plaques and tangles, rather than the actual lesions, which causes the disease. Studies described here combine the two approaches into a single model. Four studies are presented using a basic protocol of intrahippocampal lipopolysaccharide (LPS) injection to stimulate inflammation in transgenic mice. The first study looked at alpha7 nicotinic receptors during the glial response to Abeta deposits and LPS. Reactive astrocytes which immunolabeled for alpha7 were co-localized with Congophilic deposits in APP and APP+PS1 mice, and increased after LPS injection. Unfortunately, LPS injection into alpha7 knock out mice revealed the alpha7 labeling to be nonspecific. The second study evaluated the time course of protein and gene expression after LPS injection into nontransgenic mice. This experiment identified both a transient and chronic microglial inflammatory response, with changes in cell morphology. The third study evaluated a similar time course in APP mice. Concurrent with the inflammatory response, transient reductions in Abeta burden were seen, though compact plaque load was unaffected. The fourth and final study used dexamethasone to inhibit LPS-induced inflammation in APP mice. LPS injection reduced Abeta burden, but was completely blocked by dexamethasone co-treatment. Though dexamethasone inhibited LPS-induced CD45 and complement receptor 3 levels (markers of general microglial activation), dexamethasone had no effect on scavenger receptor A or Fc gamma receptor II/III levels. An overall hypothesis regarding LPS mediated reductions in Abeta can be proposed: It is not the presence of the LPS molecule, nor the upregulation of receptors involved in phagocytosis, but rather general glial cell activation that mediates Abeta removal. Thus, a phagocytic cell must not only bind Abeta (by various receptors) but must also be capable of engulfing the material (via general cell activation). Taken together, these studies suggest that some level of inflammation in AD is beneficial and responsible for maintaining a balance between amyloid deposition and removal.

Inhalation of chemical substances can cause irritation to airways and in high doses acute airway injury. When mice are exposed to the alkylating nitrogen mustard analogue melphalan they develop an acute airway inflammation with a rapid influx of neutrophils to the lungs. The acute phase is followed by long-term respiratory complications characterized by bronchitis, lung fibrosis, and airway hyperreactivity.      In this thesis, a mouse model for chemical airway inflammation was established and the effects on the lungs in a time span from 6 hours up to 3 months were investigated in order to study both acute effects and possible chronic injury. We find that treatment with corticosteroids, e.g. dexamethasone, effectively blocks the inflammatory reaction in several ways: Neutrophil influx to the lungs is diminished, the expression of the proinflammatory cytokines interleukin (IL) -6 and IL-1b is decreased and edema formation as well as development of lung fibrosis is mitigated. In acute airway inflammation we show that the antioxidant vitamin E can be used as a possible complement to corticosteroids but not as a replacement since it causes insufficient downregulation of the inflammatory response. We show the importance of the T lymphocytes as they play a prominent role in the pathogenesis of long-term lung injuries caused by melphalan. Especially the minor gd T cell subset is of major importance orchestrating a number of responses including the acute cytokine and neutrophil response and late-phase lung fibrosis. In order to find the critical time for dexamethasone treatment, mice were exposed to melphalan, treated with dexamethasone at specific time points and lung physiology and airway reactivity was measured in anaesthetized, tracheostomized mice using a small animal ventilator. From these results we conclude that an early treatment, i.e. within one hour after exposure, with dexamethasone is needed to prevent chronic lung injury.  This thesis was undertaken with the main goal to better understand the pathogenesis of melphalan-induced airway inflammation. We believe that our findings have shed new light in this area of research and hope that this increased knowledge may be of future clinical use.