This project focussed on a protein called tear lipocalin that is believed to interact with the lipid layer of the tears and to promote tear film stability. By modulating this protein, it was proposed that tear film stability could be increased, hence the modulation of lipocalin was suggested as a goal for dry eye therapy. The effects on tear lipocalin expression of two potential therapies for dry eye, pharmacological stimulation with phosphodiesterase inhibitors and hormonal regulation with aldosterone and oestrogen HRT were investigated. Initially a rabbit model was employed and the rabbit tear protein profile was characterised. Stimulation of rabbit secretion using phosphodiesterase compounds did not alter rabbit tear lipocalin secretion. Clinical trial of phosphodiesterase compounds in humans did not alter tear lipocalin expression but variation in tear lipocalin isoform expression was noted and new isoforms of tear lipocalin were identified. The steroid hormone aldosterone appeared to modulate rabbit lipocalin and low MW protein expression. A clinical trial to examine the effect of gender, menopause and oestrogen hormone replacement therapy (HRT) on lipocalin secretion demonstrated that oestrogen HRT down regulated lipocalin secretion, increased the thickness of the lipid layer and improved symptomatology compared to the untreated menopause group. High levels of tear lipcalin in the menopause group were associated with symptoms of ocular burning, suggesting that increasing tear lipocalin levels might aggravate the ocular symptoms associated with dry eye. In this thesis it was demonstrated that tear lipocalin secretion was modulated by steroid hormones, but did not appear to be modulated by phosphodiesterase inhibitors. Variation in tear lipocalin concentration did not correlate with measures of tear film stability and indeed, high levels of tear lipocalin may be deleterious for dry eye symptoms. Further analysis of tear a stimulants and hormones will lead to better understanding of tear regulation and will open avenues for dry eye therapy. The application of proteomic tools to tear film will advance our understanding of tear film composition and the role each component in tear film stability. / Doctor of Philosophy (PhD)

NO

Natural proteins can evolve new three-dimensional structures through mutations in their amino acid sequence. For protein families that exhibit such structural diversity, a major challenge is to understand the scope and nature of structure variation and its relationship to sequence evolution. The Cordes laboratory has begun using transitive homology-based methods to identify, target and structurally characterize natural sequences intermediate between pairs of proteins with distant sequence similarity and different structures. As a proof of principle, this dissertation describes structural studies of two proteins in different families as separate case studies, one involving secondary structure evolution and the other involving topological rearrangement. In the first case, crystallography was applied to solve the structure of a sequence intermediate identified through transitive homology analysis of the Cro transcription regulator family. Comparison with another member resulted in finding two proteins with significant sequence similarity yet different secondary structure compositions and folds. In the second case, transitive homology analysis was applied to look at two members of the insect salivary lipocalins, one with the canonical sequential all-antiparallel β-barrel topology, and another with a unique strand-swapped topology. Three sequence intermediate members were found that each have direct sequence similarity to both topologically distinct relatives. Targeting these sequence intermediate members for structural characterization by NMR led to assignment of the canonical lipocalin topology for one intermediate. The results from these two cases indicate that structurally diverse families may contain members with similar sequences but different folds. As such, transitive homology mapping offers a method to identify and target those members for structural characterization.

Diabetic nephropathy is a common diabetic microvascular disease with a prevalence of about 10% to 42%. Research has shown that neutrophil gelatinase-associated lipocalin (NGAL) levels would increase rapidly in the urine and blood of patients with acute kidney failure. NGAL may represent an early and predictive kidney injury biomarker due to the increase of NGAL occurs earlier than that of molecules (creatinine, cystatin C and £]2-microglobulin) for traditional assessment of renal injury in renal disease samples. To evaluate the association of plasma level of NGAL and £]2-microglobulin with diabetic nephropathy, this study was performed on 21 diabetic patients without nephropathy as the control group and 21 patients with diabetic nephropathy stage 2, 26 patients with stage 3, 9 patients with stage 4 and 16 patients stage 5 as the study group. Collection of blood and measurements of all cases were approved by the ethical committee. The results indicate that the levels of blood urea nitrogen (BUN), creatinine, NGAL, and £]2-microglobulin of study group were significantly higher than control group (P<0.001), while the glomerular filtration rate (GFR) was significantly lower than the control group (P<0.001). Linear regression analysis show that NGAL was positively correlated with white blood cells, BUN, creatinine, £]2-micrglobulin and negatively correlated with GFR; and £]2-micrglobulin was positively correlated with BUN, creatinine, NGAL and negatively correlated with GFR. All results indicate that plasma NGAL levels in diabetic nephropathy were positively correlated with renal function parameters, and closely correlated with kidney injury, suggesting that NGAL may play an important role in the progression of diabetic nephropathy.

No description available.

Introdução: A injúria renal aguda (IRA) é uma complicação comum em pacientes submetidos a transplante hepático, sendo associada a altas taxas de morbidade e mortalidade. O desenvolvimento de IRA após transplante hepático é influenciado por vários fatores do período perioperatório. As limitações para o uso da creatinina sérica (Scr) impulsionaram pesquisas para descoberta de biomarcadores mais sensíveis, específicos e precoces no diagnóstico da IRA, como a Lipocalina Associada à Gelatinases de Neutrófilos (NGAL). Objetivo: Avaliar se o padrão de elevação de NGAL urinário (UNGAL) e plasmático (PNGAL), no perioperatório do transplante hepático, pode predizer diagnóstico e gravidade da IRA; necessidade de terapia renal substitutiva (TRS) na primeira semana; e mortalidade até 60 dias pós-cirurgia. Metodologia: Foram coletadas amostras de urina e sangue no perioperatório de transplante hepático dos pacientes elegíveis que concordaram em participar do estudo e assinaram o TCLE. Nesses pacientes, foram avaliados: microscopia, bioquímica urinária, PNGAL, UNGAL e Scr antes da anestesia, após a reperfusão portal, 6, 18, 24 e 48 horas após a cirurgia. O diagnóstico de IRA foi baseado no critério da creatinina pelo KDIGO. O NGAL foi medido utilizando NGAL Test (TM) PETIA (Bioporto). O critério de injúria pelo NGAL foi baseado no ponto de corte determinado pela melhor sensibilidade versus especificidade (ponto J Younden\'s Index) na curva de característica de operação de receptor convencional (ROC). Foram analisados tempo para diagnóstico por NGAL e creatinina e gravidade da IRA entre os grupos IRA por biomarcador e Scr. Foram avaliados desfechos: tempo de internação, necessidade de diálise e mortalidade durante a internação hospitalar. Resultados: Foram incluídos 100 pacientes > 18 anos submetidos a transplante hepático de junho de 2013 a junho de 2015. A média de idade foi de 58 anos (+/-12,25), 64 pacientes masculinos, 14 não caucasianos. Cinquenta e nove desenvolveram IRA moderada a severa (estádio 2 e 3) nos primeiros 7 dias após o transplante e 38 pacientes necessitaram de TRS durante a internação. A taxa de mortalidade foi de 26% no primeiro ano. O grupo com IRA foi significativamente mais jovem (53 versus 57 anos), com maior MELD funcional (16 versus 14,p=0,01) e gravidade pelo SOFA (14 versus 12, p=0,0001). Necessidades de uso de droga vasoativa, ventilação mecânica, tempo de internação na UTI e hospital foram significativamente maiores no grupo IRA. O PNGAL, após 18 horas do transplante, foi capaz de predizer o diagnóstico de IRA pela creatinina com área sob a curva (AUC) de 0,74 (IC95% 0,60 -0,88), sensibilidade 87%, especificidade 71% e valor preditivo positivo (VPP) 79%. O UNGAL teve padrão de elevação mais precoce do que o PNGAL no diagnóstico da IRA, com seu melhor desempenho, 6 horas após o transplante, apresentando AUC de 0,76 (IC 95% 0,67 -0,86), sensibilidade 68%, especificidade 76% e VPP 80%. Na avaliação do tempo para diagnóstico da IRA, o PNGAL e UNGAL, apresentaram uma elevação respectivamente, 28 e 23 horas antes da creatinina sérica. Na avaliação do padrão de elevação para outros desfechos (gravidade da IRA, necessidade de TRS e mortalidade), o UNGAL foi significativamente maior nos períodos intra e pré-operatório e teve o melhor desempenho 6 horas após a cirurgia, com AUC para TRS e mortalidade, respectivamente, de: 0,85 (0,77 -0,93) e 0,87 (IC 95%0,73 -0,99). O PNGAL apresentou elevação do padrão um pouco mais tarde, com melhor desempenho 18 horas após a cirurgia, com AUC de 0,84 (IC95% 0,67-0,94) para TRS e 0,81 (IC95% 0,74-0,93) para não sobreviventes. Conclusão: A análise do padrão de elevação do PNGAL e do UNGAL no perioperatório do transplante hepático permitiu o diagnóstico precoce da IRA, em média 1 dia antes do diagnóstico pela creatinina. O UNGAL demonstrou ser biomarcador mais precoce e bom preditor para: desenvolvimento de IRA, gravidade IRA, necessidade de TRS e mortalidade. Estudos futuros devem avaliar se o uso clínico destes biomarcadores poderia melhorar os desfechos destes pacientes. / Introduction: Acute kidney injury (AKI) is a common complication in patients undergoing liver transplantation, associated a high rate of morbidity and mortality. The development of AKI after liver transplantation (LT) is affected by several factors existing in the perioperative period. The limitations to the use of serum creatinine (Scr), advanced the search for more sensitive, specific and early biomarkers to diagnose AKI, such as the Neutrophil Gelatinase-Associated Lipocalin (NGAL). Objective: To evaluate if the pattern elevation of urinary (UNGAL) and plasma (PNGAL) NGAL, in the perioperative of the LT, can predict the diagnosis and severity of AKI, need replacement renal therapy (RRT) in the first week and mortality until 60 days after surgery. Methods: Urine and blood samples were collected in the perioperative period of liver transplantation of patients who signed the informed consent. Urine microscopy, biochemistry, PNGAL, UNGAL and Scr were assessed before anesthesia, after portal reperfusion, 06, 18, 24 and 48 hours after surgery. AKI diagnosis was based on KDIGO serum creatinine criterion. The NGAL was measured using NGAL Test (TM) PETIA (Bioporto). The criterion of injury by NGAL was based in the value of cutoff determinate by best sensitive versus specificity (point J Younden\'s Index) of the conventional receiver operating characteristic curve (ROC). We analyzed the time to AKI diagnosis by NGAL and by creatinine. Time of hospitalization, need for dialysis and mortality during hospital were also analyzed within the groups. Results: A hundred patients aged 18 or older undergoing liver transplant from June 2013 to June 2015 were enrolled in the study. Mean age was 58 years (+/-12,25), 64 were male and 14 non-Caucasian. Fifty-nine developed moderate to severe AKI (stages 2 and 3) during the first 7 days after LT and 38 patients needed RRT during hospital stay. The mortality rate in the first year was 26%. The AKI group was significantly younger (53 versus 57 years, p=0,01), had a greater functional MELD before transplant (16 versus 14, p=0,0001) and more severe SOFA score at ICU admission. Need for vasoactive drug, mechanical ventilation, length of ICU and hospital stay were higher in the AKI group. Urinary NGAL had an earlier elevation pattern than the PNGAL. The best performance for UNGAL was 06 hours after transplantation, with an AUC of 0.76 (95% CI 0.67-0.86), sensitivity 68%, specificity 76% and PPV 80%. The PNGAL after 18 hours of transplantation was able to predict the diagnosis of AKI by creatinine with an AUC of 0.74 (95% CI 0.60-0.88), sensitivity 87%, specificity 71% and PPV 79%. In the analysis of time to AKI diagnosis, the PNGAL and UNGAL reached the cutoff for AKI diagnosis respectively 28 and 23 hours before serum creatinine. Urinary NGAL was significantly higher in the perioperative period in patients that needed dialysis or died. The best performance was six hours after LT with with with AUC of 0,85 (CI 95% 0,77 -0,93) to predict RRT need and 0,87 (CI 95%0,73 -0,99) for mortality. Plasma NGAL elevation presented the best performance 18 hours after surgery, with an AUC to predict RRT need of 0,84 (CI 95% 0,67-0,94) and of 0,81 (CI95% 0,74-0,93) to predict mortality. Conclusion: The analysis of the elevation pattern the PNGAL and the UNGAL in the perioperative of the liver transplantation allowed an early AKI diagnosis. The UNGAL was an earlier predictor of AKI, AKI severity, need RRT and mortality. Future studies should assess whether the clinical use of these biomarkers could improve the outcome of these patients

No description available.

Introdução: A injúria renal aguda (IRA) é uma complicação comum em pacientes submetidos a transplante hepático, sendo associada a altas taxas de morbidade e mortalidade. O desenvolvimento de IRA após transplante hepático é influenciado por vários fatores do período perioperatório. As limitações para o uso da creatinina sérica (Scr) impulsionaram pesquisas para descoberta de biomarcadores mais sensíveis, específicos e precoces no diagnóstico da IRA, como a Lipocalina Associada à Gelatinases de Neutrófilos (NGAL). Objetivo: Avaliar se o padrão de elevação de NGAL urinário (UNGAL) e plasmático (PNGAL), no perioperatório do transplante hepático, pode predizer diagnóstico e gravidade da IRA; necessidade de terapia renal substitutiva (TRS) na primeira semana; e mortalidade até 60 dias pós-cirurgia. Metodologia: Foram coletadas amostras de urina e sangue no perioperatório de transplante hepático dos pacientes elegíveis que concordaram em participar do estudo e assinaram o TCLE. Nesses pacientes, foram avaliados: microscopia, bioquímica urinária, PNGAL, UNGAL e Scr antes da anestesia, após a reperfusão portal, 6, 18, 24 e 48 horas após a cirurgia. O diagnóstico de IRA foi baseado no critério da creatinina pelo KDIGO. O NGAL foi medido utilizando NGAL Test (TM) PETIA (Bioporto). O critério de injúria pelo NGAL foi baseado no ponto de corte determinado pela melhor sensibilidade versus especificidade (ponto J Younden\'s Index) na curva de característica de operação de receptor convencional (ROC). Foram analisados tempo para diagnóstico por NGAL e creatinina e gravidade da IRA entre os grupos IRA por biomarcador e Scr. Foram avaliados desfechos: tempo de internação, necessidade de diálise e mortalidade durante a internação hospitalar. Resultados: Foram incluídos 100 pacientes > 18 anos submetidos a transplante hepático de junho de 2013 a junho de 2015. A média de idade foi de 58 anos (+/-12,25), 64 pacientes masculinos, 14 não caucasianos. Cinquenta e nove desenvolveram IRA moderada a severa (estádio 2 e 3) nos primeiros 7 dias após o transplante e 38 pacientes necessitaram de TRS durante a internação. A taxa de mortalidade foi de 26% no primeiro ano. O grupo com IRA foi significativamente mais jovem (53 versus 57 anos), com maior MELD funcional (16 versus 14,p=0,01) e gravidade pelo SOFA (14 versus 12, p=0,0001). Necessidades de uso de droga vasoativa, ventilação mecânica, tempo de internação na UTI e hospital foram significativamente maiores no grupo IRA. O PNGAL, após 18 horas do transplante, foi capaz de predizer o diagnóstico de IRA pela creatinina com área sob a curva (AUC) de 0,74 (IC95% 0,60 -0,88), sensibilidade 87%, especificidade 71% e valor preditivo positivo (VPP) 79%. O UNGAL teve padrão de elevação mais precoce do que o PNGAL no diagnóstico da IRA, com seu melhor desempenho, 6 horas após o transplante, apresentando AUC de 0,76 (IC 95% 0,67 -0,86), sensibilidade 68%, especificidade 76% e VPP 80%. Na avaliação do tempo para diagnóstico da IRA, o PNGAL e UNGAL, apresentaram uma elevação respectivamente, 28 e 23 horas antes da creatinina sérica. Na avaliação do padrão de elevação para outros desfechos (gravidade da IRA, necessidade de TRS e mortalidade), o UNGAL foi significativamente maior nos períodos intra e pré-operatório e teve o melhor desempenho 6 horas após a cirurgia, com AUC para TRS e mortalidade, respectivamente, de: 0,85 (0,77 -0,93) e 0,87 (IC 95%0,73 -0,99). O PNGAL apresentou elevação do padrão um pouco mais tarde, com melhor desempenho 18 horas após a cirurgia, com AUC de 0,84 (IC95% 0,67-0,94) para TRS e 0,81 (IC95% 0,74-0,93) para não sobreviventes. Conclusão: A análise do padrão de elevação do PNGAL e do UNGAL no perioperatório do transplante hepático permitiu o diagnóstico precoce da IRA, em média 1 dia antes do diagnóstico pela creatinina. O UNGAL demonstrou ser biomarcador mais precoce e bom preditor para: desenvolvimento de IRA, gravidade IRA, necessidade de TRS e mortalidade. Estudos futuros devem avaliar se o uso clínico destes biomarcadores poderia melhorar os desfechos destes pacientes. / Introduction: Acute kidney injury (AKI) is a common complication in patients undergoing liver transplantation, associated a high rate of morbidity and mortality. The development of AKI after liver transplantation (LT) is affected by several factors existing in the perioperative period. The limitations to the use of serum creatinine (Scr), advanced the search for more sensitive, specific and early biomarkers to diagnose AKI, such as the Neutrophil Gelatinase-Associated Lipocalin (NGAL). Objective: To evaluate if the pattern elevation of urinary (UNGAL) and plasma (PNGAL) NGAL, in the perioperative of the LT, can predict the diagnosis and severity of AKI, need replacement renal therapy (RRT) in the first week and mortality until 60 days after surgery. Methods: Urine and blood samples were collected in the perioperative period of liver transplantation of patients who signed the informed consent. Urine microscopy, biochemistry, PNGAL, UNGAL and Scr were assessed before anesthesia, after portal reperfusion, 06, 18, 24 and 48 hours after surgery. AKI diagnosis was based on KDIGO serum creatinine criterion. The NGAL was measured using NGAL Test (TM) PETIA (Bioporto). The criterion of injury by NGAL was based in the value of cutoff determinate by best sensitive versus specificity (point J Younden\'s Index) of the conventional receiver operating characteristic curve (ROC). We analyzed the time to AKI diagnosis by NGAL and by creatinine. Time of hospitalization, need for dialysis and mortality during hospital were also analyzed within the groups. Results: A hundred patients aged 18 or older undergoing liver transplant from June 2013 to June 2015 were enrolled in the study. Mean age was 58 years (+/-12,25), 64 were male and 14 non-Caucasian. Fifty-nine developed moderate to severe AKI (stages 2 and 3) during the first 7 days after LT and 38 patients needed RRT during hospital stay. The mortality rate in the first year was 26%. The AKI group was significantly younger (53 versus 57 years, p=0,01), had a greater functional MELD before transplant (16 versus 14, p=0,0001) and more severe SOFA score at ICU admission. Need for vasoactive drug, mechanical ventilation, length of ICU and hospital stay were higher in the AKI group. Urinary NGAL had an earlier elevation pattern than the PNGAL. The best performance for UNGAL was 06 hours after transplantation, with an AUC of 0.76 (95% CI 0.67-0.86), sensitivity 68%, specificity 76% and PPV 80%. The PNGAL after 18 hours of transplantation was able to predict the diagnosis of AKI by creatinine with an AUC of 0.74 (95% CI 0.60-0.88), sensitivity 87%, specificity 71% and PPV 79%. In the analysis of time to AKI diagnosis, the PNGAL and UNGAL reached the cutoff for AKI diagnosis respectively 28 and 23 hours before serum creatinine. Urinary NGAL was significantly higher in the perioperative period in patients that needed dialysis or died. The best performance was six hours after LT with with with AUC of 0,85 (CI 95% 0,77 -0,93) to predict RRT need and 0,87 (CI 95%0,73 -0,99) for mortality. Plasma NGAL elevation presented the best performance 18 hours after surgery, with an AUC to predict RRT need of 0,84 (CI 95% 0,67-0,94) and of 0,81 (CI95% 0,74-0,93) to predict mortality. Conclusion: The analysis of the elevation pattern the PNGAL and the UNGAL in the perioperative of the liver transplantation allowed an early AKI diagnosis. The UNGAL was an earlier predictor of AKI, AKI severity, need RRT and mortality. Future studies should assess whether the clinical use of these biomarkers could improve the outcome of these patients

No description available.

No description available.