Les maladies rénales chroniques (MRC) et l'insuffisance rénale aiguë (IRA) sont des problèmes essentiels de santé publique en raison de l'augmentation continue de leur fréquence et du manque de solutions thérapeutiques contre ces maladies. L'acide lysophosphatidique (LPA) est un lysophospholipide bioactif qui induit un large éventail de réponses cellulaires par le biais de récepteurs membranaires spécifiques (LPA1 à LPA6) couplés aux protéines G. Dans ce travail, nous nous sommes intéressés aux effets biologiques et au métabolisme du LPA dans les MRC et l'IRA. Des travaux antérieurs de l'équipe avaient montré que le LPA contribuait, via le récepteur LPA1, au développement de la fibrose tubulointerstitio (TIF) dans un modèle de MRC chez la souris : l'obstruction urétérale. Dans la première partie de la thèse nous avons étudié l'implication du LPA dans un modèle plus avancé de MRC: la néphrectomie subtotale (SNX) chez la souris. Nos travaux ont montré que 5 mois après chirurgie les souris (SNX) développaient une albuminurie massive associée à une TIF sévère et à une hypertrophie glomérulaire. Chez ces souris la concentration en LPA mesurée par chromatographie liquide en spectrométrie de masse en tandem était augmentée dans l'urine et étroitement corrélée à l'albuminurie et à la TIF. En parallèle, nous avons observé une diminution de l'expression rénale des Lipid-Phosphate Phosphatases (LPP 1, 2 et 3) responsables de l'inactivation du LPA. Nous avons également observé que l'expression rénale des récepteurs LPA1, 2, 3 et 4 était diminuée chez les souris Snx. Nous avons conclu que les effets délétères éventuels du LPA dans le développement de la MRC chez les souris SNX était vraisemblablement lié à une augmentation de sa production rénale plutôt qu'à une sensibilité accrue du rein au LPA. Des travaux antérieurs avaient montré que l'injection de LPA protégeait contre l'apparition des lésions rénales induites par ischémie/reperfusion chez la souris. Une autre étude avait montré que le LPA permettait d'atténuer l'inflammation systémique et les dommages aux organes induits par un choc septique. Dans la deuxième partie de la thèse, nous avons étudié l'influence du LPA sur l'IRA induite par une endotoxémie au LPS (lipopolysaccharide) chez la souris. Nous avons observé que l'injection de LPA permettait d'atténuer l'élévation d'urée et de créatinine plasmatiques, ainsi que l'augmentation d'expression rénale de cytokines inflammatoires (IL-6, TNFa, MCP-1) induites par le LPS. Le LPA a également empêché la baisse d'expression rénale du facteur PGC1a ainsi que les altérations ultra-structurales des mitochondries rénales induites par le LPS. In vitro, le LPA atténue l'augmentation d'expression des cytokines pro-inflammatoires (TNFa et MCP-1) induite par le LPS dans les macrophages RAW264. Enfin, nos travaux ont montré que l'endotoxémie au LPS chez la souris entrainait une réduction de la concentration urinaire de LPA associée à une réduction des enzymes anaboliques LPA (autotaxine et acylglycérol kinase) et une élévation de l'expression de de LPP2, dans le cortex rénal. Nous en avons conclu que l'IRA associée à l'endotoxémie pourrait être liée, au moins en partie, à une réduction de la production rénale de LPA et, par voix de conséquence, de ses effets anti-inflammatoires protecteurs de la fonction rénale. En conclusion, notre travail montre que les variations de production rénale de LPA pourraient jouer un rôle important dans le développement des maladies rénales. L'augmentation du LPA dans les MRC favoriserait ses effets délétères (fibrose, inflammation). Sa réduction dans l'IRA réduirait ses effets anti-inflammatoires. Cibler le catabolisme LPA pourrait donc être une approche intéressante dans le traitement des maladies rénales. / Both chronic kidney diseases (CKD) with consecutive development of end stage renal disease (ESRD) and acute kidney injury (AKI) represent worrying problems for healthcare system due to its increased frequency and the lack of efficient treatments. Lysophosphatidic acid (LPA) is a bioactive lysophospholipid that elicits a wide range of cell responses (proliferation, migration, transformation, contraction etc.) through the activation of specific G protein-coupled receptors (LPA1 to LPA6). In this work we were interested in involvement of the LPA and changes in its metabolism in CKD and AKI. Previous works showed that LPA exerts pro-fibrotic activity and contributes to development of tubulointerstitioal fibrosis (TIF) after ureteral obstruction through activation of LPA1 receptors. In the first part of the thesis we were interested whether LPA signalization is involved in more advanced model of the disease. We found that 5 months after subtotal nephrectomy (SNX) mice develop massive albuminuria, TIF and glomerular hypertrophy compared to control animals. LPA concentration measured by liquid chromatography tandem mass spectrometry was increased in urine but not in plasma of animals. That increase in LPA significantly correlated with albuminuria and TIF. In addition we found a decreased renal expression of lipid phosphate phosphatases (LPP1, 2 and 3) that are responsible for the degradation of LPA by dephosphorylation. Moreover, the expression of LPA1-LPA4 receptors is down-regulated, whereas LPA5 and LPA6 are unchanged. We concluded here that the possible deleterious effect of LPA in the development of CKD in SNX mice was likely related to its increased production rather than an increased sensitivity of the kidney to LPA. Since LPA was reported previously to protect kidney damage in the course of ischemia/reperfusion injury, and that it was able to mitigate the systemic inflammation and organ damage in sepsis, we were interested in second part of the thesis to determine whether exogenous and/or endogenous LPA might protect against sepsis-associated AKI. C57BL/6 mice were treated with exogenous LPA 18:1 1 hour before being injected with the lipopolysaccharide (LPS) and AKI was analyzed after 24h. LPA pre-treatment significantly mitigated the LPS-induced elevation of plasma urea and creatinine, lessened the up-regulation of inflammatory cytokines (IL-6, TNFa, MCP-1) and completely prevented the down-regulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1a) in kidney. LPA also prevented LPS-mediated alterations of renal mitochondria ultrastructure. In vitro, pre-treatment with LPA 18:1 (10 µM) significantly attenuated LPS-induced up-regulation of the pro-inflammatory cytokines (TNFa and MCP-1) in RAW264 macrophages. In addition we found that LPS led to the reduction of urinary LPA concentration that was associated with a reduction in LPA anabolic enzymes (autotaxin and acylglycerol kinase), and an elevation in LPA catabolic enzyme (lipid phosphate phosphatase 2) expression in kidney cortex. We concluded hereby that exogenous LPA exerts protection against endotoxemia-induced kidney injury. Moreover, the observation that LPS reduces the renal production of LPA suggests that sepsis-associated AKI could be mediated, at least in part, by alleviation of the protective action of endogenous LPA. In general our work shows that LPA local metabolism is altered in both forms of kidney diseases. In course of sepsis-induced AKI LPS leads to increased local catabolism of LPA leading to low availability of the phospholipid and alleviating its protective effect whereas in advanced CKD the local catabolism of the phospholipid is decreased with subsequent increase of urine LPA that favors development of the disease. Targeting LPA catabolism can be an interesting approach in treatment of kidney diseases.

Chronic kidney disease (CKD) is a non-communicable progressive disease that can lead to kidney failure or end-stage renal disease. In Nigeria, many people do not have access to health care due to extreme poverty, which means that those suffering from diabetes or high blood pressure, or both diseases, which have been identified as the 2 main risk factors, may not know their health status. The purpose of this phenomenological study was to explore the level of CKD awareness among Nigerians and if cultural beliefs affect individuals' health seeking behaviors because of the diverse nature of the Nigerian population. The protection motivation theory provided the framework for the study. Data were collected through semi-structured interviews with 14 participants, and data analysis included traditional coding. Findings indicated that CKD awareness in Nigeria is low. The social change implication is that the findings may be used to increase awareness of the CKD mortality and morbidity rate in Nigeria to facilitate the development and implementation of health policies that could lower the morbidity and mortality rate of CKD.

Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1628. Advisers: Belinda M. Reininger; Henry S. Brown. Includes bibliographical references.

The PAX gene family of transcription factors plays a prominent role during embryogenesis however can be aberrantly re-activated during tumorigenesis and contributes to the malignant phenotype. / During embryonic kidney development, PAX2 exerts an anti-apoptotic function however its expression typically attenuates during the post-natal period. On the other hand, PAX2 aberrant expression is observed in the majority of Renal Cell Carcinomas (RCC). RCC is resistant to chemotherapy; up-regulation of anti-apoptotic genes is recognized to contribute to tumor resistance to chemotherapy. We hypothesized that the anti-apoptotic effect of the PAX2 gene that is expressed in RCC cells contributes to RCC and their resistance to chemotherapy-induced cell death. / Human embryonic kidney (HEK293) cells transfected with a PAX2 expression vector and exposed to cisplatin, were protected from apoptosis compared to control cells. Conversely, murine collecting duct cells stably transfected with PAX2 antisense cDNA had twofold increases in cisplatin-induced apoptosis. Similarly, PAX2 knockdown using PAX2 siRNA in RCC cells CAKI-1 and ACHN enhances cisplatin-induced apoptosis in vitro. / To test the combination of PAX2 expression silencing and cisplatin treatment in vivo we developed a model of renal tumors by injecting ACHN cells as a xenograft under the skin of nude mice. I showed that a PAX2 shRNA successfully knocks down PAX2 mRNA and protein levels in a RCC cell line (ACHN). ACHN cells stably transfected with shRNAs targeted against the PAX2 homeodomain, are more susceptible to cisplatin-induced caspase-3 activation than the control ACHN cell line. Furthermore, growth of subcutaneous ACHN/shPAX2 xenografts in nude mice is significantly more responsive to cisplatin therapy than control of ACHN cell tumors. This work proposes PAX2 as a potential therapeutic gene target in metastatic renal cell carcinoma and suggests that adjunctive PAX2 knockdown may enhance the efficacy of chemotherapeutic agents such as cisplatin. / Wilms tumor, the most common pediatric renal cancer, is thought to arise from a progenitor cell of the metanephric mesenchyme that fails to complete nephrogenesis. In addition to its characteristic triphasic histology, WT can exhibit myogenic differentiation. Myogenic programming during muscle development is controlled by a PAX3 transcription factor determinant for muscle development; unexpectedly PAX3 transcriptional activity has been recently identified in the embryonic mouse kidney. These observations led us to hypothesize that PAX3 plays a role during kidney development. Furthermore, we predict that if PAX3 expression is verified during renal development, PAX3 may also be expressed in Wilms tumor with a myogenic component. / I showed that PAX3 is expressed in the metanephric mesenchyme and stromal compartment of the developing mouse kidney. In a panel of 20 Wilms tumors, PAX3 was identified in tumor samples with myogenic histopathology. Furthermore, mutations of WT1 were consistently associated with PAX3 expression in Wilms tumors and modulation of WT1 expression in HEK293 cells was inversely correlated with the level of endogenous PAX3 protein. / This work supports a novel model of normal renal development in which progenitor cells of the metanephric blastema express PAX3 when targeted toward the stromal cell fate. Suppression of PAX3 is integral to the mesenchyme-to-epithelium transition, which defines the nephrogenic cell fate and may be accomplished, in part, by WT1. Conversely, failure to suppress PAX3 may account for the myogenic phenotype in a subset of WT1-negative Wilms tumors.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

DISSERTATION (PH.D.)--THE UNIVERSITY OF MICHIGAN / CO-CHAIRMEN: ARNOLD MONTO; GENE HIGASHI

DISSERTATION (PH.D.)--THE UNIVERSITY OF MICHIGAN / CO-CHAIRMEN: ARNOLD MONTO; GENE HIGASHI

Made available in DSpace on 2015-07-22T20:50:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo deste trabalho é estabelecer os valores hematológicos e avaliar a capacidade fagocítica de macrófagos peritoneais do robalo relacionado ao sexo, estádio de maturação gonadal e ciclo sazonal. Foi coletado sangue de 135 animais e utilizado para as determinações de: número de eritrócitos, hematócrito, taxa de hemoglobina, cálculos dos índices hematimétricos (volume corpuscular médio e concentração de hemoglobina corpuscular média), contagens total e diferencial de leucócitos e de trombócitos. A capacidade fagocítica e o índice fagocítico foram determinados após inoculação de S. cerevisiae na cavidade peritoneal. Os resultados hematológicos separados por sexo mostraram valores do número de eritrócitos, trombócitos e leucócitos totais em machos estatisticamente superiores àqueles em fêmeas. Já os valores de VCM em fêmeas foram superiores àqueles em machos. Quanto aos valores do número de eritrócitos, do hematócrito e da taxa de hemoglobina analisados separadamente por sexo e estádio de maturação gonadal mostraram-se significantemente elevados em machos no estádio maduro e diminuídos no estádio repouso. A análise dos resultados hematológicos e da atividade fagocítica relacionada ao sexo e ao ciclo sazonal mostrou diferenças estatisticamente significantes em ambos os sexos com hematócrito e taxa de hemoglobina baixos no inverno e altos nas demais estações, volume corpuscular médio altos no verão e baixos no inverno e outono; leucócitos totais e trombócitos baixos na primavera e elevados no outono; linfócitos baixos no inverno e verão e elevados na primavera; capacidade fagocítica e índice fagocítico elevados no verão e baixos no inverno e outono. Os resultados mostraram que os valores hematológicos em machos foram estatisticamente superiores àqueles em fêmeas, os valores eritrocitários em machos aumentam com o avanço da maturação gonadal e que o inverno corresponde à estação do ano menos favorável à resposta hematológica e fagocítica para a sobrevivência do robalo criado em cativeiro. Os parâmetros estudados poderão ser utilizados, para a manutenção e controle desta espécie na criação em cativeiro. / The objective of this work was to determine hematological parameters and the phagocytic capacity of peritoneal macrophages of the fat snook related to sex, stage of gonadal maturation and seasonal cycle. The hematological results did not show significant differences between males and females. With respect to stage of gonadal maturation, only erythrocytes numbers (RBC), in females, was found to be significantly elevated in stage III (maturing) and decreased in V (spent). An analysis of the results of the erythrocyte and leukocyte series, thrombocytes and phagocytic activity related to sex and seasonal cycle showed statistically significant differences: a) in males, hematocrit (Ht) and hemoglobin concentration (Hb) were elevated in the spring and low in the winter; b) in both sexes, mean corpuscular volume (MCV) was high in the spring and summer and low in the fall; c) in females, thrombocytes numbers were elevated in the fall and low in the other seasons; d) in both sexes, phagocytic capacity (PC) and phagocytic index (PI) were higher in the summer and lower in the fall. The results showed that spring and summer correspond to seasons of the year for better hematological and phagocytic responses for survival of the fat snook in its natural habitat. The parameters studied could be utilized for evaluation of the health status in its own habitat or in captivity. / TEDE / BV UNIFESP: Teses e dissertações

Made available in DSpace on 2016-12-23T13:56:14Z (GMT). No. of bitstreams: 1 Barbara dos Reis Santos.pdf: 1741973 bytes, checksum: a2c1145354df049aa6d015f4c78a7cfa (MD5) Previous issue date: 2012-10-15 / A doença renal crônica (DRC) já é considerada uma pandemia e indivíduos por ela acometidos possuem um sistema imunológico debilitado e são mais suscetíveis a doenças infecciosas e entre estas a tuberculose (TB) que também é reconhecidamente um problema global de saúde pública. Temos então que indivíduos portadores de DRC possuem um risco aumentado para a TB e com evidências de que por conta de seu estado de imunossupressão estes indivíduos também possuem um pior desfecho durante o tratamento. Dessa forma, este estudo pretendeu investigar aspectos epidemiológicos e clínicos da convergência da TB e DRC. RESULTADOS: Através de uma revisão sistemática e meta-análise encontramos uma prevalência agrupada de TB em indivíduos com DRC submetidos ao transplante renal de 2,51% (95% IC = 2,17 2,85). No Espírito Santo esta prevalência foi de 1,54% (95% IC 0,71% - 2,38%) e apresentou associação com história prévia de TB (OR = 40,71; 95% IC 2,54 651,84), número de episódios infecciosos (OR = 1,35; 95% IC 1,10 1,67) e uso de sirolimus na imunossupressão inicial (OR = 41,40; 95% IC 2,59 660,31). Ainda nesta população a mediana do tempo para o desenvolvimento de TB após o transplante renal foi de quatro anos e, entre os treze indivíduos identificados com TB, oito apresentaram doença pulmonar, sete necessitaram de hospitalização e quatro morreram em consequência da TB. Já os fatores que diferenciam as chances de abandono, óbito por TB e óbito por outra causa em relação cura no tratamento da TB, entre indivíduos com DRC no Brasil, foram os estratos etários; alcoolismo; AIDS; estar institucionalizado num presídio; estar sob a terapia de substituição renal transplante; retornar para o tratamento após abandono prévio; possuir um raio X de tórax suspeito para TB; e ter indicação ou ter realizado tratamento diretamente observado. CONCLUSÃO: Os desafios apresentados pela relação entre a TB e os indivíduos com DRC, que vão desde a alta prevalência até um pior desfecho para o tratamento, são imensos e nossos dados ajudam a reforçar a necessidade da implementação de estratégias para controle da TB direcionadas a determinados grupos populacionais, priorizando especialmente os portadores de doenças crônicas não transmissíveis como a DRC / Chronic kidney disease (CKD) is consider a pandemic. Subjects with CKD have an impaired immunologic system and are more susceptible to infectious diseases including tuberculosis (TB) - another global public health problem. Thus, subjects with CKD have a higher risk to TB and there are evidences that they also have a poor treatment outcome. This study aims to investigate the epidemiological and clinical aspects of CKD and TB convergence. RESULTS: Through a systematic review and meta-analysis we found a pooled prevalence of TB in kidney transplant recipients of 2.51% (95% CI = 2.17 2.85). In Espírito Santo state this prevalence was 1.54% (95% CI 0.71% 2.38%) and was associated with: prior TB history (OR = 40.71; CI 95% 2.54 651.84), number of infectious episodes (OR = 1.35; CI 95% 1.10 1.67) and use of sirolimus as initial immunosuppressive drug (OR = 41.40; CI 95% 2.59 660.31). The median of years for TB development after the transplantation in the same sample was four years. Among thirteen subjects with TB, eight had pulmonary disease, seven needed hospitalization and four died due to TB. Regarding the factors that differentiate the chances of abandonment and death from cure among Brazilian subjects with CKD were: age, alcoholism, AIDS, jail, kidney transplantation, previous abandonment of treatment, ray-X suspicious for TB and directly observed therapy. CONCLUSION: The challenges shown by the relationship between TB and CKD, since a higher prevalence until a poor treatment outcome, are enormous and our data strengthen the need of strategies to control TB with priority subjects with chronic non communicable disease like CKD