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Vascular access dysfunction is a cause of morbidity and mortality in chronic kidney disease (CKD) patients that require hemodialysis. The major cause of vascular access failure is venous stenosis due to neointimal hyperplasia (NH). Vascular smooth muscle cells (VSMC) are critical for the development of NH lesions, as they have the ability to modulate their phenotype from a "contractile" to a "synthetic" phenotype in the presence of uremia, through the regulation of sensor genes for uremia danger signals and VSMC-specific differentiation genes. Recent research indicates that Caspase-1 (casp-1) activation plays an essential role in sensing metabolic danger signal-associated molecular patterns and initiating vascular inflammation. Carbamylated LDL, a uremic toxin that has been shown to be found in higher levels in patients with CKD and in CKD murine models when compared to controls, and could play a role in casp-1 activation. Therefore, the goal of this project is to examine the role of cLDL/CKD-driven casp-1 activation in VSMC and CKD-related NH. We have established a CKD mouse model and published on CKD-associated vascular remodeling. We exposed wild type and caspase-1 knockout mice to our CKD model, analyzed and quantified the NH lesion formed. We also examined in vitro and ex-vivo changes in VSMC-specific differentiation genes when exposed to uremic serum and cLDL, in the presence or absence of caspase-1 inhibitor. We found that CKD serum induces with casp-1 activation and phenotypic changes in VSMCs from a "contractile" to a "synthetic" phenotype, which are reversed with casp-1 inhibition. In an ex-vivo model using relative quantification we found that VSMC contractile markers α -Actin, Calponin, SM-22, and Smoothelin gene expression of CKD mouse carotid VSMC were higher in casp-1 knockout mice when compared to wild-type (1.40, 1.28, 1.22, 1.41 respectively). Also using an in-vivo model, relative quantification of α-actin decreased from 1.0 to 0.329 when VSMCs were exposed to uremic serum and but increased back to 0.588 when Caspase-1 inhibitor is added. The relative quantification of Calponin also decreased from 1.0 to 0.394 when exposed to uremic serum and increased back to 0.601 with caspase-1 inhibitor. We also found that caspase-1 deficiency significantly reversed CKD-related vascular remodeling in casp-1 knockout mice and reduced NH volume by 50% from 1,440,023in wild-type mice to 71,069 µm2 in casp-1 knockouts (p-value 0.002). This evidence provides evidence that casp-1 plays a critical role in NH formation. Furthermore our results provide a novel insight over the therapeutic potential of casp-1 inhibitors for CKD induced NH and other inflammation induced vascular remodeling. / Public Health

Patients with chronic kidney disease (CKD) develop hyperhomocysteinemia (HHcy), have increased inflammatory monocytes (MC) and 10-times higher cardiovascular mortality than the general population. Here, we investigated HHcy-related MC differentiation in CKD. Twenty seven CKD and CVD, and 14 healthy subjects were recruited. CD40 was selected as a CKD-induced MC activation marker by mining for CKD-MC-mRNA screen database. We found that CD14++CD16+ MC, often denoted as inflammatory subset, soluble CD40 ligand (sCD40L), and TNFα/IL-6 levels were augmented in CVD and CKD subjects. CD40hiCD14++CD16+ MC, plasma homocysteine (Hcy) and S-adenosylhomocysteine (SAH) levels were increased in CVD and further elevated in CKD subjects. In cultured human peripheral blood mononuclear cells, CKD patient serum, Hcy, CD40L and TNFα/IL-6 induced CD40hiCD14++CD16+ MC differentiation, which was prevented by Hcy-lowering folic acid and neutralizing antibodies against TNFα and IL-6. Interestingly, CD14++CD16+ and CD40hiCD14++CD16+ MCs were negatively correlated with plasma S-adenosylmethionine/SAH (SAM/SAH) ratios, an indicator of methylation status, in CKD and CVD subjects. In white blood cells (WBC) isolated from CKD and CVD subjects with lower SAM/SAH ratios, hypomethylation was identified on the CG pair of NFκB consensus element in the core promoter located at the CpG island of CD40 gene by DNA methylation mapping using bisulfite converting pyrosequencing. Moreover, Hcy inhibited DNA methyltransferase-1 activity in cultured human blood MC. In conclusion, HHcy induces CD14++CD16+ and CD40hiCD14++CD16+ MC differentiation, at least in part, via sCD40L induction and CD40 DNA hypomethylation in CKD and CVD subjects. To study the role of CD40 in the development of kidney pathology and vascular disease, we then established mouse model of CKD-induced CVD (5/6 nephrectomy CKD model plus left carotid artery ligation) in CD40-/- mice. Bone marrow (BM)-derived cells were traced by the transplantation of BM cells from enhanced green fluorescent protein (EGFP) transgenic CD40+/+ mice after sublethal irradiation of the recipient CD40-/- mice. We demonstrated here that CKD accelerated carotid artery atherosclerosis, exacerbated metabolism, increased spleen weight and circulating CD40+ inflammatory MC, and further increased differentiation of mononuclear phagocytic cells (MPC); CD11b+F4/80- MC, CD11b+F4/80+ macrophage (Mϕ) and CD11c+CD11b+F4/80+ bone marrow-derived dendritic cell in the kidney and aorta, which were abolished by CD40-/- mice. We also found that CKD kidney elevated CD40 expression and induced MC chemotactic signals; CCL2, CCL12, and CCL5 chemokines, which were abolished in CD40-/- mice. In conclusion, our results suggest that CD40 induction in the chronic kidney disease mediates kidney chemokine production, which in turn contributes to acceleration of myeloid cell infiltration, MPC differentiation, and carotid artery atherosclerosis. / Pharmacology

Endoplasmic reticulum (ER) stress, which results from the aggregation of misfolded proteins in the ER, has been implicated in many forms of kidney injury, including hypertensive nephrosclerosis. ER stress induction increases levels of active TGFβ1, a pro-fibrotic cytokine, which can lead to epithelial-to-mesenchymal transition (EMT) in renal proximal tubular cells. EMT occurs when epithelial cells undergo phenotypic changes, which can be prevented by inhibiting ER stress. Further, the ER stress protein TDAG51 is essential for the development of TGFβ1-mediated fibrosis. The low molecular weight chemical chaperone 4-phenylbutyrate (4-PBA) can protect against ER stress-mediated kidney injury. It acts directly on the kidney, and can prevent ER stress, renal tubular damage, and acute tubular necrosis. In a tunicamycin-mediated model of kidney injury, this damage is prevented primarily through repression of the pro-apoptotic ER stress protein CHOP. Along with providing renoprotective effects, 4-PBA can inhibit endothelial dysfunction and elevated blood pressure in a rat model of essential hypertension. In addition to lowering blood pressure, 4-PBA reduces contractility, augments endothelial-dependent vasodilation, and normalizes media-to-lumen ratio in mesenteric arteries from spontaneously hypertensive rats. Further, ER stress leads to reactive oxygen species generation, which is reduced with 4-PBA. Dahl salt-sensitive rats given 4-PBA are protected from hypertension, proteinuria, albuminuria, and renal pathology. Rats provided with vasodilatory medications demonstrate that lowering blood pressure alone is not renoprotective. In fact, endothelial dysfunction, as demonstrated by an impaired myogenic response, is culpable in the breakdown of the glomerular filtration barrier and subsequent renal damage. As such, alleviating ER stress using 4-PBA serves as a viable therapeutic strategy to preserve renal function and prevent ER stress-mediated endothelial dysfunction, renal fibrosis, glomerular filtration barrier destruction, and progression of hypertensive nephrosclerosis. / Thesis / Doctor of Philosophy (PhD) / Chronic kidney disease is characterized by progressive loss of kidney function, and is a major public health problem. Kidney cells make proteins that help the kidney function properly. However, if the proteins are made improperly, the kidney does not function as well. This can lead to poor filtration and protein in the urine, damage to important kidney structures, and kidney scarring. High blood pressure, a risk factor for kidney disease, is often accused of causing kidney damage. This thesis shows that malfunctioning blood vessels can cause kidney injury, and lowering blood pressure may not prevent this. However, there are pharmacological molecules that can protect the kidney from damage. These molecules help the cells make proteins properly, preventing blood vessel malfunction and kidney damage. Our findings suggest that helping blood vessels and kidney cells create properly functioning proteins is more protective for the kidney than lowering blood pressure alone.

Encephalitozoon cuniculi, Toxoplasma gondii and Sarcocystis neurona are intracellular parasites that infect a wide range of mammalian host species including domestic cats. The prevalence of antibodies to these parasites in cats was examined using an indirect immunofluorescence antibody assay. E. cuniculi targets the kidneys of rabbits but the prevalence of disease in cats is unknown. Chronic kidney disease (CKD) is a common cause of illness in cats. T. gondii is a widespread parasite of cats; however, it is not considered a major causative agent of CKD. The first hypothesis was that E. cuniculi and T. gondii are unrecognized causes of chronic kidney disease in domestic cats. Serum and plasma samples were examined for protozoal antibodies from 232 feline patients at the VMRCVM Teaching Hospital. Thirty-six of the 232 samples met the IRIS criteria for CKD. Antibodies to E. cuniculi were found in 15 samples, 4 of which came from cats with CKD. Antibodies to T. gondii were found in 63 samples; 10 cats of the 63 had CKD. These were not significantly different from cats with no CKD and the null hypothesis was rejected. Domestic cats, armadillos, raccoons and skunks are intermediate hosts (IH) for S. neurona while opossums are the definitive host (DH). The seroprevalence of S. neurona was examined in domestic cats from Virginia and Pennsylvania. The second hypothesis was that domestic cats are important IH for S. neurona transmission. A low seroprevalence was found in 32 of the 441 cats and the null hypothesis was rejected. / Master of Science in Life Sciences

The increased prevalence of chronic kidney disease (CKD) has become a major global health burden. This increase in CKD burden parallels the increase in hypertension prevalence. In addition, increasing evidence suggest that genetics play a strong role in the susceptibility for renal disease. Inbred mouse strains C57BL/6 and 129S6SvEv differ in their susceptibility to kidney disease when subjected to hypertension using the DOCA/salt uninephrectomy model of hypertension. Similar to others, we found the 129S6SvEv mice to be susceptible to develop severe glomerulosclerosis, whereas the C57BL/6 mice are comparatively resistant. To identify new candidate genes that are involved in the pathogenesis of glomerular disease, we used microarray technology to compare the glomerular transcriptome of both strains and determine changes in glomerular gene expression when subjected to the DOCA/salt uninephrectomy model of systemic hypertension. This approach was accompanied with ultrastructural analysis and glomerular stiffness measurements to identify corresponding structural changes. Here, we have identified novel genes associated with strain differences and hypertension, and we used immunohistochemistry to validate their expression in podocytes and glomerular arterioles in murine and human kidneys. The increased understanding of the molecular mechanisms underlying hypertension-associated podocyte injury and glomerular damage which will result from these studies, will ultimately lead to identification of novel pharmacologic targets or therapeutic strategies for patients with hypertension and renal disease. / 2017-11-02T00:00:00Z

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24999号 / 医博第5033号 / 新制||医||1070(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 長船 健二, 教授 小林 恭, 教授 尾野 亘 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Patients with chronic kidney disease are at increased risk of cardiovascular disease. These patients are often excluded in randomized controlled trials of treatments for cardiovascular disease, leading to greater uncertainty behind treatment effects in this population. Further, patients with kidney disease experience unique complications from accepted therapies for the general population, e.g.; long-term anticoagulation may be result in further kidney injury called anticoagulation-related nephropathy. However, incidence and magnitude of this acute kidney injury are not adequately measured in past randomized controlled trials of anticoagulation. Chapters in this thesis aim to increase our understanding the relationship between cardiac and kidney disease. Chapters 2 and 3 focus on the optimal prosthetic valve in dialysis patients requiring valve replacement surgery. Chapter 2 is a systematic review and meta-analysis comparing the short and long-term outcomes of two prosthetic valves implanted in dialysis patients. Chapter 3 is a survey of physicians aiming to understand the current practice of nephrologists, cardiologists, and cardiac surgeons caring for dialysis patients requiring valve replacement surgery and their preference for either prosthetic valve based on patient factors. Chapter 4 explores the interaction between an individual’s baseline kidney function and the effect on stroke reduction of occluding the left atrial appendage. This is accomplished by a secondary analysis of the Left Atrial Appendage Occlusion Study 3 (LAAOS III). Chapter 5 is a rationale and study design of LIMIT-Renal, a substudy of Low INR to Minimize Bleeding with Mechanical Valves Trial (LIMIT). This substudy aims to validate the existence of anticoagulation-related nephropathy, a form of acute kidney injury in patients receiving long-term anticoagulation, and its magnitude on renal health. Chapter 6 is the conclusion of the thesis and discusses key findings, strengths and limitations, future directions, and potential obstacles. / Thesis / Doctor of Science (PhD) / Individuals with chronic kidney disease are at an increased risk of heart disease and those receiving treatment for heart disease may be at an increased risk of developing kidney disease. Chapters in this thesis investigate the understudied interplay of heart disease and renal disease, for which an overview is presented in chapter 1. Chapter 2 addresses the uncertainty surrounding an optimal prosthetic valve in dialysis patients requiring surgical valve replacement surgery. Chapter 3 aims to understand the perceptions and preferences of physicians caring for dialysis patients needing valve replacement surgery. Chapter 4 explores the interaction between occluding the left atrial appendage and baseline kidney function on stroke reduction using data from the Left Atrial Appendage Occlusion Study 3 (LAAOS III). Chapter 5 is the design and rationale for a substudy of Low INR to Minimize Bleeding with Mechanical Valves Trial (LIMIT) exploring a form of acute kidney injury in patients receiving blood-thinning medications. Chapter 6 discusses the key findings from each chapter, their strengths and limitations, future directions, and potential obstacles.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2008. / A fluoroscopy-guided needle-positioning system is designed and tested as a first prototype for aiding urologists in gaining fast, accurate and repeatable kidney calyx access during a PCNL procedure while also reducing radiation exposure of the people involved. Image guidance is realized by modelling the fluoroscopic system as an adapted pinhole camera model and utilizing stereo vision principles on a stereo image pair. Calibration, distortion correction and image processing algorithms are implemented on images of a designed calibration object. Thereafter the resulting variables are used in the targeting of the calyx with the aid of a graphical user interface. The required relative translation and rotation of the needle from its current position to the target is calculated and the system is adjusted accordingly. Using digital cameras, needle placement accuracies of 2.5 mm is achieved within the calibrated volume in a simulated environment. Similar results are achieved in the surgery room environment using the fluoroscopic system. Successful needle access in two porcine kidney calyxes concluded the testing

Recentemente descrevemos que ratos tratados com o inibidor do sistema NF-?B pirrolidina ditiocarbamato (PDTC) durante a lactação desenvolvem uma hipertensão arterial na fase adulta, sem lesão renal aparente, caracterizando assim um novo modelo hipertensão essencial. No presente estudo, nós investigamos se a Uninefrectomia (UNx) associada a uma sobrecarga salina (SS) na dieta revelaria uma possível disfunção renal, agravando assim a hipetensão arterial e levando a lesões renais. Ratos Munich-Wistar recém-nascidos foram divididos em 2 grupos: Controle, sem qualquer tratamento; e PDTCLact, recebendo PDTC (280 mg/Kg/dia) na água do bebedouro do 0 aos 20 dias após o nascimento. Após 10 semanas de vida, 120 ratos machos submetidos à Uninefrectomia e foram estudados em dois protocolos. No protocolo 1, os ratos machos foram subdivididos em: UNx+NS, ratos Controle recebendo dieta padrão (NS); PDTCLact+UNx+NS, ratos PDTCLact recebendo NS; UNx+SS, ratos Controle recebendo SS; PDTCLact+UNx+SS, ratos PDTCLact recebendo SS. Após 12 semanas, os animais do Grupo UNx+SS apresentaram hipertensão, aumento da albuminúria e lesões renais moderadas. Nos animais do grupo PDTCLact+UNx+SS a hipertensão, esclerose glomerular e a deposição de Colágeno-1 intersticial apresentaram um aumentado exacerbado, juntamente com lesões arteriolares do tipo \"casca de cebola\", estresse oxidativo, ativação do NF-kB, intenso infiltrado de macrófagos, linfócitos e aumento de células positivas para Angiotensina II, mesmo com a renina plasmática reduzida. Para investigar o papel do sistema renina-angiotensina neste modelo, no protocolo 2, 40 ratos foram divididos em: PDTCLact+UNx+SS, como descrito no protocolo 1; PDTCLact+UNx+SS+L, ratos tratados com Losartan (50 mg/kg) na água do bebedouro. O tratamento com Losartan foi capaz de atenuar as lesões glomerulares e a inflamação renal. Esses resultados indicam que a integridade do sistema NF-kB é fundamental para o desenvolvimento adequado do rim e a manutenção da homeostase do sódio na fase adulta. Paradoxalmente, esse mesmo sistema contribui para o desenvolvimento da lesão renal quando a disfunção renal causada por sua inibição durante a nefrogênese é desmascarada por UNx associada ao SS / Recently we described that rats treated with the NF-?B inhibitor pyrrolidine dithiocarbamate (PDTC) during lactation develop high blood pressure hypertensive in adult life, without apparent functional or structural damage to the kidneys, thus providing a new model of essential hypertension. In the present study, we investigated whether uninephrectomy (UNx) associated with saline overload would unveil a possible renal dysfunction, thus aggravating arterial hypertension and leading to hemodynamically mediated renal injury. Munich-Wistar rat pups were divided into 2 groups: Control, receiving no treatment; and PDTCLact, receiving PDTC (280 mg/kg/ day) in the drinking water from 0 to 20 days after birth. At 10 weeks of age, 120 male rats underwent uninephrectomy and were studied in two protocols. In Protocol 1, rats were subdivided into: UNx+NS, control rats receiving normal salt (NS) diet; PDTCLact+UNx+NS, PDTCLact rats receiving NS; UNx+HS, control rats receiving high-salt (HS) diet; PDTCLact+UNx+HS, PDTCLact rats receiving HS. After 12 weeks, the UNx+HS animals were moderately hypertensive and exhibited mild albuminuria and renal injury. By contrast, arterial hypertension, glomerulosclerosis and cortical collagen-1 deposition were exacerbated in the PDTCLact+UNx+HS group, along with \"onion skin\" arteriolar lesions, evidence of oxidative stress, NF-kB activation and intense infiltration by macrophages, lymphocytes and angiotensin II-positive cells, even though circulating renin was depressed. To investigate the role of the renin-angiotensin system in this setting, 40 rats were divided into: PDTCLact+UNx+HS, treated as described before; and PDTCLact+UNx+HS+L, receiving in addition Losartan, 50 mg/kg in drinking water. Losartan treatment strongly atenuated glomerular injury and renal inflammation. The NF-kB system is essential for the kidneys to develop properly and maintain sodium homeostasis in adult life. Paradoxically, this same system contributes to renal injury when renal dysfunction caused by its inhibition during nephrogenesis is unmasked by UNx associated to HS