No description available.

A citrullinemic fibroblast cell line was used in this study to investigate two biochemical pathways involving citrulline. In the first section, the genetic mutation responsible for the argininosuccinate synthetase (-ASS) deficiency (1-5% activity) in this cell line was investigated. PCR analysis of the ASS cDNA revealed that the mRNA coding region (1236bp) was intact, showing no signs of major rearrangements. The ASS cDNA (1307bp) was cloned and sequenced and showed the presence of a single base mutation at position 1045bp, which represented a G->A transition. This mutation resulted in a glycine -> serine amino acid substitution at position 324 in the ASS subunit protein sequence. Although this glycine residue was not found to occur in any potential substrate binding sites, it was shown to be highly conserved among species, indicating a possible role of this amino acid in ASS catalytic activity. In the second section, the presence of the nitric oxide pathway in fibroblasts was investigated. Inducible nitric oxide synthase activity was assayed by measuring the production of ¹⁴C-citrulline from ¹⁴C-arginine after cytokine stimulation. By using the citrullinemic cell line (ASS deficient) any citrulline that may be produced by this pathway would accumulate, allowing detection. Under the assay conditions that were tested, no detectable ¹⁴C-citrulline was formed. Evidence suggests that human fibroblasts have the potential to synthesise nitric oxide, although a more sensitive assay system may need to be employed (longer cytokine activation, nitrite/nitrate detection).

No description available.

Zou Wei. / Thesis submitted in: December 2001. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 98-119). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgements --- p.ii / Publication lists --- p.iii / Abstract --- p.ix / Abbreviations --- p.xiii / List of tables and figures --- p.xiv / Chapter Chapter 1: --- General Introduction --- p.1 / Chapter 1.1. --- Endothelium-dependent relaxation in coronary and pulmonary circulation --- p.1 / Chapter 1.1.1. --- Endothelium-derived relaxing factors --- p.2 / Chapter 1.1.1.1. --- Nitric Oxide --- p.3 / Chapter 1.1.1.2. --- PGI2 --- p.5 / Chapter 1.1.1.3. --- EDHF --- p.6 / Chapter 1.1.2. --- EDHF in coronary and pulmonary circulation --- p.8 / Chapter 1.1.2.1. --- EDHF in coronary circulation --- p.8 / Chapter 1.1.2.2. --- EDHF in pulmonary circulation --- p.9 / Chapter 1.2. --- Effect of hyperkalemia on EDHF-mediated relaxation --- p.10 / Chapter 1.3. --- Organ Preservation Solutions --- p.13 / Chapter 1.3.1. --- Euro-Collins solution --- p.14 / Chapter 1.3.2. --- University of Wisconsin solution --- p.15 / Chapter Chapter 2: --- Objectives and research approaches --- p.16 / Chapter 2.1. --- Objectives --- p.16 / Chapter 2.1.1. --- "Endothelium-dependent relaxation resistant to INDO, L-NNA, and HbO in porcine and pulmonary coronary micro-arteries" --- p.16 / Chapter 2.1.2. --- "EET11,12 and EDHF-mediated function in porcine coronary micro-arteries" --- p.17 / Chapter 2.1.3. --- "Comparison of EC or UW solution on endothelium-dependent relaxation resistant to INDO, l-NNA, and HbO in porcine pulmonary arteries" --- p.17 / Chapter 2.2. --- Research approaches --- p.18 / Chapter 2.2.1. --- "Endothelium-dependence of the relaxation by BK or EET11,12" --- p.18 / Chapter 2.2.2. --- Effect of hypothermic storage with EC and UW solution on EDHF-related relaxation --- p.18 / Chapter 2.2.3. --- Time-dependent alteration of endothelium-dependent relaxation in pulmonary micro-arteries by EC and UW solution --- p.19 / Chapter 2.2.4. --- Effect of HbO in endothelium-dependent relaxation --- p.19 / Chapter Chapter 3: --- Material and Methods --- p.21 / Chapter 3.1. --- General Methods --- p.21 / Chapter 3.1.1. --- Porcine heart and lung collection and transportion / Chapter 3.1.2. --- Myograph --- p.21 / Chapter 3.1.3. --- Myosight --- p.24 / Chapter 3.1.4. --- Anatomizing blood vessel --- p.24 / Chapter 3.1.5. --- Mounting --- p.24 / Chapter 3.1.6 --- Normalization --- p.26 / Chapter 3.1.6.1. --- Normalization of coronary micro-artery --- p.27 / Chapter 3.1.6.2. --- Normalization of pulmonary micro-artery --- p.28 / Chapter 3.1.7. --- Precontraction --- p.30 / Chapter 3.1.8. --- Endothelium-dependent relaxation --- p.31 / Chapter 3.2. --- Coronary artery studies --- p.32 / Chapter 3.2.1. --- Porcine heart harvest and anatomy --- p.32 / Chapter 3.2.2. --- Characteristic of histology of porcine coronary micro-artery --- p.32 / Chapter 3.3. --- Pulmonary artery studies --- p.35 / Chapter 3.3.1. --- Porcine lung harvest and anatomy --- p.35 / Chapter 3.3.2. --- Characteristic of histology of porcine pulmonary micro- artery --- p.36 / Chapter 3.4. --- Drugs --- p.41 / Chapter 3.4.1. --- Drugs --- p.41 / Chapter 3.4.2. --- Preparation of oxyhemoglobin solution --- p.41 / Chapter 3.5. --- Statistical Analysis --- p.42 / Chapter 3.5.1. --- Calculation of EC50 --- p.42 / Chapter 3.5.2. --- Statistical analysis --- p.42 / Chapter Chapter 4: --- "Epoxyeicosatrienoic Acids (EET11,12) May Partially Restore EDHF-Mediated Function in Coronary Micro-Arteries" --- p.43 / Chapter 4.1. --- Abstract --- p.43 / Chapter 4.2. --- Introduction --- p.44 / Chapter 4.3. --- Experimental Protocol --- p.45 / Chapter 4.3.1. --- Precontraction --- p.45 / Chapter 4.3.2. --- "EDHF-mediated (INDO, L-NNA, and HbO-resistant) relaxation" --- p.45 / Chapter 4.3.3. --- "EET11,12-mediated relaxation after exposure to hyperkalemia" --- p.46 / Chapter 4.3.4. --- "The effect of incubation with EET11,12 on the BK-induced, EDHF-mediated relaxation" --- p.46 / Chapter 4.4. --- Results --- p.47 / Chapter 4.4.1. --- Resting force --- p.47 / Chapter 4.4.2. --- HbO and U46619-induced contraction force --- p.48 / Chapter 4.4.3. --- "EET11,12-induced relaxation in coronary micro-arteries after exposure to hyperkalemia" --- p.49 / Chapter 4.4.4. --- "The EDHF-mediated relaxation to BK resistant to INDO, l- NNA,and HbO" --- p.51 / Chapter 4.4.4.1. --- Incubated in either hyperkalemic solution (K+ 20mmol/L) or Krebs' solution (control) --- p.51 / Chapter 4.4.4.2. --- "Incubated in either hyperkalemic solution (K+ 20mmol/L) plus EET11,12 or Krebs' solution (control)" --- p.53 / Chapter 4.5. --- Discussion --- p.57 / Chapter 4.5.1. --- EDHF plays an important role in the coronary micro-arteries --- p.57 / Chapter 4.5.2. --- "EDHF-mediated (INDO, l-NNA, and HbO-resistant) relaxation in the coronary micro-arteries" --- p.58 / Chapter 4.5.3. --- "EET11,12 may partially mimic the EDHF-mediated relaxation in the porcine coronary micro-artery" --- p.59 / Chapter 4.5.4. --- "Effect of EET11,12 added in hyperkalemia may partially restore the EDHF-mediated relaxation in the porcine coronary micro-arteries" --- p.59 / Chapter Chapter 5: --- Impaired EDHF-Mediated Relaxationin Porcine Pulmonary Micro-arteries by Cold Store with Euro-Collin's and University of Wisconsin Solution --- p.61 / Chapter 5.1. --- Abstract --- p.61 / Chapter 5.2. --- Introduction --- p.62 / Chapter 5.3. --- Experimental Protocol --- p.64 / Chapter 5.3.1. --- Precontraction --- p.64 / Chapter 5.3.2. --- "Role of EDHF-mediated (INDO, L-NNA and HbO-resistant) relaxation in porcine pulmonary micro-arteries by BK orA23187" --- p.64 / Chapter 5.3.3. --- Effect of hyperkalemia or preservation solutions (EC or UW) on the EDHF-mediated relaxation by BK or A23187 --- p.65 / Chapter 5.3.3.1. --- The effect of hyperkalemia --- p.65 / Chapter 5.3.3.2. --- Effect of EC solution on the EDHF-mediated relaxation --- p.65 / Chapter 5.3.3.3. --- Effect of UW solution on the EDHF-mediated relaxation --- p.66 / Chapter 5.3.3.4. --- The effect of UW and EC solutions on the contractility of the pulmonary micro-artery --- p.66 / Chapter 5.4. --- Results --- p.66 / Chapter 5.4.1. --- Resting force --- p.66 / Chapter 5.4.2. --- U46619-induced contraction force --- p.67 / Chapter 5.4.3. --- Role of EDHF-mediated relaxation induced by BK or A23187 --- p.67 / Chapter 5.4.4. --- The effect of hyperkalemia --- p.71 / Chapter 5.4.5. --- Effect of EC solution on the EDHF-mediated relaxation --- p.72 / Chapter 5.4.6. --- Effect of UW solution on the EDHF-mediated relaxation --- p.73 / Chapter 5.4.7. --- The effect of UW and EC solution on the contractility of the pulmonary micro-artery --- p.73 / Chapter 5.5. --- Discussion --- p.77 / Chapter 5.5.1. --- EDHF-mediated endothelial function exists in the pulmonary micro-circulation --- p.77 / Chapter 5.5.2. --- Hyperkalemia exposure reduces EDHF-related relaxation and possible mechanism --- p.78 / Chapter 5.5.3. --- The effect of EC and UW solutions on the EDHF-media relaxation in the pulmonary micro-arteries --- p.79 / Chapter Chapter 6: --- General Discussion --- p.82 / Chapter 6.1. --- Endothelium-dependent vasodilators: BK and A23187 --- p.82 / Chapter 6.2. --- EDHF in porcine coronary and pulmonary micro-arteries --- p.84 / Chapter 6.2.1. --- EDHF in porcine coronary micro-arteries --- p.84 / Chapter 6.2.2. --- EDHF in porcine pulmonary micro-arteries --- p.87 / Chapter 6.2.3. --- Vascular stretch and release of endothelium-derived vasodilators --- p.87 / Chapter 6.2.4. --- "EET11,12" --- p.88 / Chapter 6.3. --- "Endothelium-dependent relaxation resistant to INDO, L- NNA, and HbO in porcine coronary and pulmonary microcirculation" --- p.89 / Chapter 6.4. --- "Alteration of endothelium-dependent relaxation resistant to INDO, l-NNA, and HbO after exposure to hyperkalemia" --- p.90 / Chapter 6.5. --- "Alteration of endothelium-dependent contraction resistant to INDO, L-NNA, and HbO after exposure to EC or UW solutions" --- p.91 / Chapter 6.6. --- Clinical implications --- p.92 / Chapter 6.7. --- Limitations --- p.93 / Chapter 6.7.1. --- Common limitations --- p.93 / Chapter 6.7.2. --- Limitation of in vitro study --- p.93 / Chapter 6.8. --- Future work --- p.94 / Chapter Chapter 7: --- Conclusion --- p.96 / References --- p.98 / Appendies / "Wei Zou, Qin Yang, Anthony PC Yim, & Guo-Wei He Epoxyeicosatrienoic acids (EET11,12) may partially restore endothelium- derived hyperpolarizing factor-mediated function in coronary micro- arteries. Annals of Thoracic Surgery. 2001; 72(12): 1970~1976."

Diss. (sammanfattning) Linköping : Univ., 2001. / Härtill 4 uppsatser.

Dong Yingying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 99-125). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgement --- p.ii / Publication list --- p.iii / Abstract (English) --- p.ix / Abstract (Chinese) --- p.xii / Abbreviations --- p.xiv / List of figures / tables --- p.xvi / Chapter Chapter 1. --- General Introduction / Chapter 1.1 --- The role of endothelium in regulating vascular tone --- p.1 / Chapter 1.1.1 --- Nitric oxide (NO) --- p.2 / Chapter 1.1.2 --- Endothelium-derived hyperpolarizing factor (EDHF) --- p.7 / Chapter 1.1.3 --- Prostacyclin (PGI2) --- p.20 / Chapter 1.2 --- EDHF-mediated endothelial function in coronary circulation --- p.22 / Chapter 1.2.1 --- Role of EDHF in coronary microarteries --- p.23 / Chapter 1.2.2 --- Role of EDHF in cardiac veins --- p.24 / Chapter 1.3 --- Effect of ischemia-reperfusion on endothelial function in coronary circulation --- p.25 / Chapter 1.3.1 --- Ischemia-reperfusion injury --- p.26 / Chapter 1.3.2 --- Effect of ischemia-reperfusion on endothelial function in coronary microarteries --- p.28 / Chapter 1.3.3 --- Effect of ischemia-reperfusion on endothelial function in cardiac veins --- p.29 / Chapter 1.4 --- Alteration of endothelial function during cardiac surgery / Chapter 1.4.1 --- Cardioplegia and organ preservation solutions --- p.31 / Chapter 1.4.2 --- Combined effects of hypoxia-reoxygenation and ST solution on endothelial function in coronary microarteries/cardiac veins --- p.34 / Chapter 1.4.3 --- Effect of nicorandil on endothelial function --- p.34 / Chapter Chapter 2. --- Materials and Methods --- p.37 / Chapter 2.1 --- Isometric force study in micro arteries/veins --- p.37 / Chapter 2.1.1 --- Preparation of vessels --- p.37 / Chapter 2.1.1.1 --- Preparation of porcine coronary microarteries --- p.37 / Chapter 2.1.1.2 --- Preparation of porcine cardiac veins --- p.37 / Chapter 2.1.2 --- Technique of setting up --- p.39 / Chapter 2.1.2.1 --- Mounting of microvessels --- p.39 / Chapter 2.1.2.2 --- Normalization procedure for microvessels --- p.39 / Chapter 2.1.3 --- EDHF-mediated vasorelaxation --- p.40 / Chapter 2.1.3.1 --- Precontraction and stimuli of EDHF --- p.40 / Chapter 2.1.3.2. --- “Truéحresponse of EDHF --- p.40 / Chapter 2.1.4 --- Data acquisition and analysis --- p.41 / Chapter 2.2 --- Hypoxia and reoxygenation --- p.41 / Chapter 2.2.1 --- Calibration of 02-special electrode --- p.41 / Chapter 2.2.2 --- Measurement of --- p.02 / Chapter 2.3 --- Statistical analysis --- p.42 / Chapter 2.4 --- Chemicals --- p.43 / Chapter Chapter 3. --- Hypoxia-Reoxygenation in Coronary Microarteries: Combined Effect with St Thomas Cardioplegia and Temperature on the Endothelium- derived Hyperpolarizing Factor and Protective Effect of Nicorandil --- p.44 / Chapter 3.1 --- Abstract --- p.44 / Chapter 3.2 --- Introduction --- p.45 / Chapter 3.3 --- Experimental design and analysis --- p.47 / Chapter 3.3.1 --- Vessel Preparation --- p.47 / Chapter 3.3.2 --- Normalization --- p.48 / Chapter 3.3.3 --- Hypoxia --- p.48 / Chapter 3.3.4 --- Effect of H-R on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.5 --- Combined effects ofH-R and ST solution on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.6 --- Effect of addition of nicorandil Krebs or ST solution under H-R on EDHF-mediated relaxation in coronary microarteries --- p.49 / Chapter 3.3.7 --- Data analysis --- p.50 / Chapter 3.4 --- Results --- p.51 / Chapter 3.4.1 --- Resting force --- p.51 / Chapter 3.4.2 --- U46619-induced contraction force --- p.51 / Chapter 3.4.3 --- Partial pressure of oxygen in hypoxia --- p.51 / Chapter 3.4.4 --- EDHF-mediated relaxation in coronary microarteries --- p.51 / Chapter 3.4.4.1 --- Effect of H-R --- p.51 / Chapter 3.4.4.2 --- Combined effects ofH-R and ST solution on EDHF-mediated relaxation --- p.52 / Chapter 3.4.4.3 --- Effects of addition of nicorandil to Krebs or ST solution under H-R on EDHF-mediated relaxation --- p.52 / Chapter 3.5 --- Discussion --- p.53 / Chapter 3.5.1 --- EDHF-mediated relaxation after exposure to H-R --- p.53 / Chapter 3.5.2 --- EDHF-mediated relaxation after H-R in ST solution at different temperature --- p.54 / Chapter 3.5.3 --- Effect of addition of nicorandil to Krebs or ST solution during H-R on EDHF-mediated relaxation --- p.55 / Chapter 3.5.4 --- Clinical implications --- p.56 / Chapter Chapter 4. --- Hypoxia-Reoxygenation in Cardiac Microveins: Combined Effect with Cardioplegia and Temperature on the Endothelial Function --- p.68 / Chapter 4.1 --- Abstract --- p.68 / Chapter 4.2 --- Introduction --- p.69 / Chapter 4.3 --- Experimental design and analysis --- p.73 / Chapter 4.3.1 --- Vessel Preparation --- p.73 / Chapter 4.3.2 --- Normalization --- p.73 / Chapter 4.3.3 --- Hypoxia --- p.73 / Chapter 4.3.4 --- Effect of H-R on EDHF-mediated relaxation in cardiac micro veins --- p.74 / Chapter 4.3.5 --- Combined effects of H-R and ST solution on EDHF-mediated relaxation in cardiac microveins --- p.74 / Chapter 4.3.6 --- Data analysis --- p.75 / Chapter 4.4 --- Results --- p.75 / Chapter 4.4.1 --- Resting force --- p.75 / Chapter 4.4.2 --- U46619-induced contraction force --- p.76 / Chapter 4.4.3 --- Partial pressure of oxygen in hypoxia --- p.76 / Chapter 4.4.4 --- EDHF-mediated relaxation after H-R in Krebs solution at 37°C --- p.76 / Chapter 4.4.5 --- EDHF-mediated relaxation after exposure to H-R in ST solution at different temperatures --- p.77 / Chapter 4.5 --- Discussion --- p.78 / Chapter 4.5.1 --- Effect of H-R on EDHF-mediated relaxation --- p.78 / Chapter 4.5.2 --- Combined effects of H-R with ST solution on EDHF-mediated relaxation --- p.80 / Chapter 4.5.3 --- Clinical implications / Chapter Chapter 5. --- General Discussion --- p.89 / Chapter 5.1 --- EDHF-mediated endothelial function in porcine coronary circulation --- p.89 / Chapter 5.1.1 --- EDHF in porcine coronary microarteries --- p.92 / Chapter 5.1.2 --- EDHF in porcine cardiac veins --- p.90 / Chapter 5.2 --- Alteration of EDHF-mediated function after exposure to H-R --- p.91 / Chapter 5.2.1 --- In coronary microarteries --- p.91 / Chapter 5.2.2 --- In cardiac veins --- p.92 / Chapter 5.3 --- Alteration of EDHF-mediated function after exposure to ST solution under H-R --- p.92 / Chapter 5.3.1 --- In coronary microarteries --- p.93 / Chapter 5.3.2 --- In cardiac veins --- p.93 / Chapter 5.4 --- EDHF-mediated function in nicorandil-supplemented ST solution under H-R in coronary microarteries --- p.93 / Chapter 5.5 --- Clinical implications / Chapter 5.5.1 --- H-R injury --- p.94 / Chapter 5.5.2 --- H-R injury and cardioplegic solution --- p.95 / Chapter 5.5.2 --- Nicorandil-supplementation in cardioplegic solution --- p.95 / Chapter 5.6 --- Limitation of the study --- p.96 / Chapter 5.7 --- Future investigations --- p.96 / Chapter 5.8 --- Conclusions --- p.97 / References --- p.99

Zhang Rongzhen. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 130-176). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Lípides nitrados (NO2-FA) são apontados como uma nova classe de mediadores lipídicos, podendo atuar como reservatórios endógenos de óxido nítrico (&#8226NO) bem como moduladores pluripotentes de sinalização celular. Recentemente, tem sido sugerido que os doadores de &#8226NO estariam envolvidos na regulação da angiogênese. Evidências contundentes indicam ainda que o processo de neovascularização poderia contribuir para a patogênese de uma serie de condições clínicas, entre elas a aterosclerose. Contudo, apesar de diversos estudos terem explorado os efeitos biológicos dos NO2-FA, os efeitos destes compostos sobre o processo de angiogênese não haviam sido descritos. Dessa maneira, o presente trabalho investigou os efeitos dos NO2-FA (derivados da nitração do ácido linoléico e oléico) noprocesso de angiogênese. Demonstrou-se que os NO2-FA podem atuar como mediadores pró-angiogênicos. Este efeito foi caracterizado em células endoteliais humanas, assim como, em modelos ex vivo e in vivo. Nas células endoteliais, observou-se que os No2-FA não influenciaram a proliferação ou a viabilidade celular, ao passo que estimularam a migração. Demonstrou-se também que os NO2-FA podem modular o brotamento ex vivo de novos vasos, em cultura de anéis de aorta de rato, bem como o processo angiogênico in vivo observado na membrana corioalantóica de embrião de galinha. Adicionalmente, os NO2-FA induziram a expressão do fator de crescimento endotelial vascular (VEGF), que é o principal mediador do processo de angiogênese. Em relação ao mecanismo de ação, os achados sugerem que os efeitos demonstrados seriam via mecanismos dependentes de &#8226NO, uma vez que foram abolidos na presença de um seqüestrador de &#8226NO, enquanto concentrações equivalentes dos lípides precursores não demonstraram qualquer influência nas condições experimentais utilizadas neste estudo. Por fim, os efeitos pró-angiogênicos dos NO2-FA foram mediados pela estabilização da proteína do fator induzível por hipóxia -1α (HIF-1α), uma vez que estes compostos promoveram acúmulo desta proteína e falharam em demonstrar efeitos indutores em células knockdown para o gene HIF-1α. Em conjunto, estes resultados indicam que os NO2-FA podem modular a migração de células endoteliais e estimular o processo de angiogênese resultante da ativação de HIF-1a via mecanismo dependente de &#8226NO. / Nitrated lipids (NO2-FA) are described as a new class of Iipid mediators that are able to act as endogenously nitric oxide (&#8226NO) reservoirs as well as pluripotent cell signaling modulators. Furthermore, recent findings suggest that &#8226NO donors could be involved in the regulation of angiogenesis. Compelling evidence also indicate that the neovascularization process might contribute to the pathogenesis of many clinical conditions, such as atherosclerosis. However, although several studies have explored the NO2-FA biological properties, the effects of these compounds on the angiogenic process remain unknown. Hence, the present study investigated the effects of the NO2-FA (derivates from the nitration of Iinoleic and oleic acids at physiological concentrations) on angiogenesis processo It is demonstrated that the No2-FA could act as pro-angiogenic mediators. This effect was observed not only in human endothelial cells but also in ex vivo and in vivo models. Using endothelial cells, it is showed that NO2-FA failed to affect cell proliferation ar influence cellular viability, but significantly stimulated cell migration. It was also found that the NO2-FA might modulate the ex vivo sprouting of new vessels as well as the in vivo angiogenic process, while inducing the expression of the vascular endothelial growth factor, the main mediator of angiogenesis. The data are consistent with the hypothesis that the observed effects mediated by NO-dependent mechanisms, since the presence of a &#8226NO scavenger abrogated the induced effects, whereas equimolar concentrations of its precursors, showed no effect on angiogenesis under our experimental conditions. Finally, the pro-angiogenic effects of NOrFA were mediated by the stabilization of the hypoxia inducible factor-1α (HIF-1α) protein, because these compounds increased the protein amount and failed to show inductive effects in HIF-1α knockdown cells. Taken together, these findings indicated that NO2-FA might modulate the endothelial cell migration and stimulate the process of angiogenesis by the HIF-1α induction through a &#8226NO-dependent mechanism.

Lípides nitrados (NO2-FA) são apontados como uma nova classe de mediadores lipídicos, podendo atuar como reservatórios endógenos de óxido nítrico (&#8226NO) bem como moduladores pluripotentes de sinalização celular. Recentemente, tem sido sugerido que os doadores de &#8226NO estariam envolvidos na regulação da angiogênese. Evidências contundentes indicam ainda que o processo de neovascularização poderia contribuir para a patogênese de uma serie de condições clínicas, entre elas a aterosclerose. Contudo, apesar de diversos estudos terem explorado os efeitos biológicos dos NO2-FA, os efeitos destes compostos sobre o processo de angiogênese não haviam sido descritos. Dessa maneira, o presente trabalho investigou os efeitos dos NO2-FA (derivados da nitração do ácido linoléico e oléico) noprocesso de angiogênese. Demonstrou-se que os NO2-FA podem atuar como mediadores pró-angiogênicos. Este efeito foi caracterizado em células endoteliais humanas, assim como, em modelos ex vivo e in vivo. Nas células endoteliais, observou-se que os No2-FA não influenciaram a proliferação ou a viabilidade celular, ao passo que estimularam a migração. Demonstrou-se também que os NO2-FA podem modular o brotamento ex vivo de novos vasos, em cultura de anéis de aorta de rato, bem como o processo angiogênico in vivo observado na membrana corioalantóica de embrião de galinha. Adicionalmente, os NO2-FA induziram a expressão do fator de crescimento endotelial vascular (VEGF), que é o principal mediador do processo de angiogênese. Em relação ao mecanismo de ação, os achados sugerem que os efeitos demonstrados seriam via mecanismos dependentes de &#8226NO, uma vez que foram abolidos na presença de um seqüestrador de &#8226NO, enquanto concentrações equivalentes dos lípides precursores não demonstraram qualquer influência nas condições experimentais utilizadas neste estudo. Por fim, os efeitos pró-angiogênicos dos NO2-FA foram mediados pela estabilização da proteína do fator induzível por hipóxia -1α (HIF-1α), uma vez que estes compostos promoveram acúmulo desta proteína e falharam em demonstrar efeitos indutores em células knockdown para o gene HIF-1α. Em conjunto, estes resultados indicam que os NO2-FA podem modular a migração de células endoteliais e estimular o processo de angiogênese resultante da ativação de HIF-1a via mecanismo dependente de &#8226NO. / Nitrated lipids (NO2-FA) are described as a new class of Iipid mediators that are able to act as endogenously nitric oxide (&#8226NO) reservoirs as well as pluripotent cell signaling modulators. Furthermore, recent findings suggest that &#8226NO donors could be involved in the regulation of angiogenesis. Compelling evidence also indicate that the neovascularization process might contribute to the pathogenesis of many clinical conditions, such as atherosclerosis. However, although several studies have explored the NO2-FA biological properties, the effects of these compounds on the angiogenic process remain unknown. Hence, the present study investigated the effects of the NO2-FA (derivates from the nitration of Iinoleic and oleic acids at physiological concentrations) on angiogenesis processo It is demonstrated that the No2-FA could act as pro-angiogenic mediators. This effect was observed not only in human endothelial cells but also in ex vivo and in vivo models. Using endothelial cells, it is showed that NO2-FA failed to affect cell proliferation ar influence cellular viability, but significantly stimulated cell migration. It was also found that the NO2-FA might modulate the ex vivo sprouting of new vessels as well as the in vivo angiogenic process, while inducing the expression of the vascular endothelial growth factor, the main mediator of angiogenesis. The data are consistent with the hypothesis that the observed effects mediated by NO-dependent mechanisms, since the presence of a &#8226NO scavenger abrogated the induced effects, whereas equimolar concentrations of its precursors, showed no effect on angiogenesis under our experimental conditions. Finally, the pro-angiogenic effects of NOrFA were mediated by the stabilization of the hypoxia inducible factor-1α (HIF-1α) protein, because these compounds increased the protein amount and failed to show inductive effects in HIF-1α knockdown cells. Taken together, these findings indicated that NO2-FA might modulate the endothelial cell migration and stimulate the process of angiogenesis by the HIF-1α induction through a &#8226NO-dependent mechanism.