Στην χρόνια νεφρική ανεπάρκεια, η μειωμένη διήθηση του πλάσματος οδηγεί στην αυξημένη συγκέντρωση τοξινών στο αίμα. Αυτό προκαλεί δυσλειτουργία του ενδοθηλίου, η οποία περιλαμβάνει την φλεγμονή, την αθηροσκλήρωση και τελικά την υπέρταση. Στο πλαίσιο της μελέτης της δράσης των μη διηθούμενων τοξινών, χρησιμοποιήθηκε ορός ασθενών πριν και μετά την αιμοκάθαρση. Ως in vitro σύστημα μελέτης, χρησιμοποιήθηκε πρωτογενής καλλιέργεια ενδοθηλιακών κυττάρων από ομφάλια φλέβα ανθρώπου (HUVEC) και ελέγχθηκε η επίδραση ορού πριν και μετά την αιμοκάθαρση, στον πολλαπλασιασμό, την απόπτωση, την μετανάστευση και την «επούλωση πληγών» των κυττάρων αυτών. Επίσης, μελετήθηκε η έκφραση των μεταλλοπρωτεϊνασών MMP-2 και MMP-9 και των αναστολέων τους TIMP-1 και 2 σε επίπεδο mRNA και πρωτεΐνης καθώς και η έκφραση του κολλαγόνου IV και της ελαστίνης. Χρόνο- και δοσο-εξαρτώμενα πειράματα έδειξαν ότι ο μετά-ορός, σε σχέση με τον προ-ορό, επάγει τον πολλαπλασιασμό, την μετανάστευση και την διαδικασία της «επούλωσης πληγών» των ενδοθηλιακών κυττάρων με στατιστικά σημαντικό τρόπο, ενώ βρέθηκε να μειώνει την απόπτωση. Επίσης βρέθηκε ότι ο προ- ορός, σε σχέση με τον μετά- ορό, επάγει με στατιστικά σημαντικό τρόπο, την έκφραση και ενεργότητα των MMP-2 και MMP-9, ενώ καταστέλλει την έκφραση καθώς και τα επίπεδα των αναστολέων TIMP-1 και TIMP-2. Τέλος καταστέλλει την έκφραση των βασικών συστατικών της εξωκυττάριας ύλης, του κολλαγόνου IV και της ελαστίνης. Συμπερασματικά, ο ορός πριν την αιμοκάθαρση φαίνεται να συμμετέχει στην δυσλειτουργία του ενδοθηλίου, καταστέλλοντας τον πολλαπλασιασμό και την μετανάστευση και επάγοντας ταυτόχρονα την απόπτωση των ενδοθηλιακών κυττάρων. Παράλληλα ο προ-ορός καταστρέφει την εξωκυττάρια ύλη των ενδοθηλιακών κυττάρων επάγοντας τις MMP-2 και -9, καταστέλλοντας τους αναστολείς τους TIMP-1 και -2 και μειώνοντας ταυτόχρονα την έκφραση του κολλαγόνου IV και της ελαστίνης. / In chronic renal disease, reduced glomerular filtration results to increased toxin concentration in blood. This leads, among others, to endothelial dysfunction which concludes inflammation, atherosclerosis and finally hypertension. In this study, in order to investigate the effect of non-filtrated toxins, we used pre-haemodialysis and post-haemodialysis serum (control) from end-stage renal patients. As in vitro system of study we used the primary endothelial cell culture from human umbilical vein (HUVEC) and the effect of pre- and post- haemodialysis serum on cell proliferation, migration, apoptosis and wound healing was investigated. In addition, the expression of matrix metalloproteases MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2 was examined. Time course and dose-response experiments revealed that pre-serum reduces proliferation, migration and wound healing, while induced apoptosis in a statistically significant manner. Pre-, compared to post-haemodialysis serum, induces the expression and activity of MMP-2 and MMP-9, while inhibits the expression of TIMP-1 and TIMP-2. Concluding, uremic toxins lead to endothelial dysfunction, inhibiting cell proliferation, cell migration and inducing apoptosis. In addition, uremic toxins contribute to the degradation of extracellular matrix, inducing MMP-2 and MMP-9 and inhibiting TIMP-1 and TIMP-2.

Renal failure uremia occurs when the kidneys fail to function properly. Despite being the main treatment, dialysis and other therapeutic approaches are not only associated with numerous long-term adverse complications often leading to morbidity and mortality events, but are also not affordable. Orally administrating Alginate-Poly-L-Lysine-Alginate microcapsules entrapping live yeast cells to treat renal failure uremia has not yet been investigated. In this thesis, the growth and microencapsulation of yeast were optimized. The efficacy of these microcapsules in removing unwanted electrolytes was tested in vitro in simulated gastro-intestinal media, in vitro in a column bioreactor and in vivo in an uremic rat model. Results showed that these novel microcapsules can not only maintain morphological stability and membrane integrity under gastro-intestinal environments and mechanical stresses, but also, preserve the viability of yeast. These microcapsules were successful in reducing urea concentrations while not harming the human GI tract's microbial flora.

No description available.

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 5 uppsatser.

Thesis (doctoral)--Uppsala University, 1983. / Bibliography: p. 24-28.

Resumo:Em humanos, a imunossupressão que ocorre em pacientes urêmicos está associada com a disfunção dos neutrófilos causada pelas toxinas urêmicas. O p-cresol se acumula no sangue de pacientes com insuficiência renal crônica (IRC) promovendo a inibição do metabolismo oxidativo dos neutrófilos. O presente trabalho teve como objetivo mensurar as concentrações plasmáticas de p-cresol em cães hígidos e com IRC e testar a hipótese de que o p-cresol livre causa disfunção neutrofílica. Para tal, foi quantificada a concentração plasmática de p-cresol por cromatografia de fase líquida (HPLC) em cães hígidos e com IRC no estágio IV. Também foi avaliado in vitro o efeito específico do p-cresol sobre o metabolismo oxidativo e a taxa de apoptose de neutrófilos de cães hígidos, considerando-se a maior concentração plasmática desta toxina observada in vivo em cães com IRC. Neutrófilos isolados de 20 cães saudáveis foram incubadas em meio de RPMI puro ou enriquecido com p-cresol e com plasma de cães com IRC. O metabolismo oxidativo dos neutrófilos foi avaliado por citometria de fluxo capilar utilizando as sondas hidroetidina e 2′,7′- diacetato de diclorofluoresceína com ou sem estímulos de acetato miristato de forbol e n-formil-metionil-leucilfenilalanina. A apoptose e a viabilidade dos neutrófilos foi quantificada em citômetro de fluxo capilar utilizando sistema Anexina V-PE, com ou sem estímulo de camptotecina. Cães com IRC apresentaram in vivo o quadro de estresse oxidativo e aumento do p-cresol plasmático. A maior concentração do p-cresol causou disfunção neutrofílica in vitro. Conclui-se que p-cresol pode estar envolvido com quadro de estresse oxidativo in vivo e que sua alta concentração diminua a viabilidade e leve a uma redução da produção de espécies reativas de oxigênio / Abstract:In humans, the immunosuppression observed in uremic patients is associated with the neutrophil dysfunction caused by uremic toxins. P-cresol accumulates in the blood of patients with chronic renal failure (CRF) promoting the inhibition of neutrophil oxidative metabolism. This study aimed to measure the plasma concentrations of p-cresol in dogs with CRF and test the hypothesis that free p-cresol causes neutrophil dysfunction. To this end, plasma concentration of p-cresol was determined using high pressure liquid chromatography (HPLC) in dogs presenting stage IV of CRF. The in vitro specific effect of p-cresol on the oxidative metabolism and apoptosis rate of neutrophils from healthy dogs was also evaluated, considering the highest plasma concentration of this toxin observed on the in vivo measurement of dogs with CRF. Isolated neutrophils from 20 healthy dogs were incubated in RPMI medium alone, supplemented with p-cresol or plasma from dogs with CRF. Neutrophil oxidative metabolism was assessed by capillary flow cytometry using the probes hydroethidine and 2',7'- dichlorofluorescein diacetate with or without stimulus with phorbol myristate acetate and N-formyl-methionyl-leucylphenylalanine. Apoptosis and viability of neutrophils were quantified also in capillary flow cytometry using Annexin V-PE system with or without stimulus with camptothecin. Dogs with CRF presented oxidative stress and increased plasma levels of p-cresol, the higher concentration of p-cresol caused in vitro neutrophil dysfunction. It can be concluded that p-cresol may be involved with in vivo oxidative stress that its higher concentration decreases the viability and lead to a reduced production of reactive oxygen species / Orientador:Paulo Cesar Ciarlini / Banca:Wagner Luis Ferreira / Banca:Alvaro José dos Santos Neto / Mestre

Resumo:Recentemente, foi relatado que na insuficiência renal crônica (IRC) canina ocorre estresse oxidativo e que a disfunção dos neutrófilos está associada ao aumento da apoptose. Dentre as muitas toxinas urêmicas que se concentram na IRC, há evidências em humanos de que as guanidinas inibem o metabolismo oxidativo dos neutrófilos, afetando a sua função bactericida. Uma revisão sistemática foi realizada sobre a relação entre os compostos guanidínicos e os neutrófilos em cães. Verificou-se que a literatura, sobre este tema, é escassa e contraditória, de modo que, foi investigado no presente estudo a relação entre a concentração de guanidina plasmática, a produção de superóxido e a apoptose de neutrófilos de cães com IRC. Aditivamente, foi investigado "in vitro" o efeito isolado do composto ácido guanidinoacético (AGA) sobre a produção de superóxido e a apoptose de neutrófilos de cães sadios. Foi possível comprovar que o grande aumento da guanidina plasmática observado em cães com IRC não está associado à alteração do metabolismo oxidativo e apoptose dos neutrófilos. O AGA inibiu o metabolismo oxidativo de neutrófilos de cães sadios sem afetar a viabilidade dessas células / Abstract:It has been recently reported that in canine chronic renal failure (CRF) there occurs oxidative stress, and that neutrophil dysfunction is associated with the increase of apoptosis. Among the many uremic toxins found in higher concentrations due to CRF, there is evidence - in humans - that guanidines inhibit the oxidative metabolism of neutrophils, affecting their bactericidal function. In this study, a systematic review of the relationship between guanidine compounds and neutrophils in dogs was undertaken. It was found that the literature on this subject is scarce and conflicting, which prompted this investigation of the relationship between the plasmatic concentration of guanidine, the production of superoxide, and the apoptosis of neutrophils in dogs with CRF. Morever, the effect of the isolated compound guanidine acetic acid (GAA) on the production of superoxide and on neutrophil apoptosis in healthy dogs was investigated in vitro. It was possible to verify that the large increase of plasmatic guanidine observed in dogs with CRF is not associated with the altered oxidative metabolism and the apoptosis of the neutrophils. The GAA inhibited the oxidative metabolism of the neutrophils in healthy dogs without affecting the viability of these cells / Orientador:Paulo Cesar Ciarlini / Banca:Fabiano Antonio Cadioli / Banca:Aureo Evangelista Santana / Mestre

Diabetes mellitus (DM) é uma doença crônica que afeta aproximadamente 382 milhões de pessoas. Atualmente, o diagnóstico de DM é baseado nos resultados dos testes da hemoglobina glicada (A1C), além dos testes baseados em glicemia. Estes testes identificam grupos diferentes de pacientese aqueles identificados pela A1C parecem ter um perfil mais desfavorável às complicações do que os identificados pelos testes de glicemia. No entanto, o uso da A1C apresenta algumas limitações e tem sido questionada como teste de escolha para o diagnóstico de DM devido a fatores que afetam a sua interpretação. A anemia pode ocasionar aumento ou diminuição dos níveis da A1C, devido à alteração no tempo de meia vida das hemácias. Hemoglobinopatias e a hemoglobina carbamilada podem aumentar ou diminuir os valores da A1C. Recentemente, estudos demonstraram que existe diferença nos níveis de A1C entre as etnias, a qual parece ser independente das alterações glicêmicas ou hematológicas. Neste trabalho analisamos a influência de possíveis fatores que podem afetar os níveis de A1C em adultos sem DM através de revisão sistemática e metanálise. Avaliamos também a associação dos níveis de A1C com os níveis de albuminúria e prevalência de DRD no momento do diagnóstico do DM tipo 2 em estudo transversal. Nossos resultados mostraram que os efeitos da HbAS e uremia sobre os níveis de A1C em indivíduos sem DM estão dentro da variação individual esperada, e não devem afetar a interpretação dos resultados de A1C para diagnosticar DM. No entanto, mais estudos são necessários para elucidar os efeitos da anemia por deficiência de ferro e/ou deficiência de ferro nos níveis de A1C. Também demostramos que os níveis de A1C são diferentes entre negros, asiáticos e latinos quando comparados com brancos na ausência de DM. Estas diferenças são relevantes quando se considera o uso da A1C como critério diagnóstico utilizando apenas um ponto de corte para todas as populações, sem considerar a origem étnica. Em relação à associação da A1C com DRD, nossos dados mostraram que indivíduos com maiores níveis de A1C tem um perfil renal desfavorável. No entanto, tanto A1Ccomo os testes baseados na glicemia apresentam baixo desempenho para identificar pacientes com albuminuria elevada.

Made available in DSpace on 2015-10-06T13:02:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-21. Added 1 bitstream(s) on 2015-10-06T13:19:28Z : No. of bitstreams: 1 000848868.pdf: 401988 bytes, checksum: 08ca73724d8938b9b116d34fb50815a0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In humans, the immunosuppression observed in uremic patients is associated with the neutrophil dysfunction caused by uremic toxins. P-cresol accumulates in the blood of patients with chronic renal failure (CRF) promoting the inhibition of neutrophil oxidative metabolism. This study aimed to measure the plasma concentrations of p-cresol in dogs with CRF and test the hypothesis that free p-cresol causes neutrophil dysfunction. To this end, plasma concentration of p-cresol was determined using high pressure liquid chromatography (HPLC) in dogs presenting stage IV of CRF. The in vitro specific effect of p-cresol on the oxidative metabolism and apoptosis rate of neutrophils from healthy dogs was also evaluated, considering the highest plasma concentration of this toxin observed on the in vivo measurement of dogs with CRF. Isolated neutrophils from 20 healthy dogs were incubated in RPMI medium alone, supplemented with p-cresol or plasma from dogs with CRF. Neutrophil oxidative metabolism was assessed by capillary flow cytometry using the probes hydroethidine and 2',7'- dichlorofluorescein diacetate with or without stimulus with phorbol myristate acetate and N-formyl-methionyl-leucylphenylalanine. Apoptosis and viability of neutrophils were quantified also in capillary flow cytometry using Annexin V-PE system with or without stimulus with camptothecin. Dogs with CRF presented oxidative stress and increased plasma levels of p-cresol, the higher concentration of p-cresol caused in vitro neutrophil dysfunction. It can be concluded that p-cresol may be involved with in vivo oxidative stress that its higher concentration decreases the viability and lead to a reduced production of reactive oxygen species

Made available in DSpace on 2015-10-06T13:03:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-17. Added 1 bitstream(s) on 2015-10-06T13:18:35Z : No. of bitstreams: 1 000848874.pdf: 475629 bytes, checksum: 8f3083521bd5dbb20833e54b2e295e0b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / It has been recently reported that in canine chronic renal failure (CRF) there occurs oxidative stress, and that neutrophil dysfunction is associated with the increase of apoptosis. Among the many uremic toxins found in higher concentrations due to CRF, there is evidence - in humans - that guanidines inhibit the oxidative metabolism of neutrophils, affecting their bactericidal function. In this study, a systematic review of the relationship between guanidine compounds and neutrophils in dogs was undertaken. It was found that the literature on this subject is scarce and conflicting, which prompted this investigation of the relationship between the plasmatic concentration of guanidine, the production of superoxide, and the apoptosis of neutrophils in dogs with CRF. Morever, the effect of the isolated compound guanidine acetic acid (GAA) on the production of superoxide and on neutrophil apoptosis in healthy dogs was investigated in vitro. It was possible to verify that the large increase of plasmatic guanidine observed in dogs with CRF is not associated with the altered oxidative metabolism and the apoptosis of the neutrophils. The GAA inhibited the oxidative metabolism of the neutrophils in healthy dogs without affecting the viability of these cells