Active clinical trials for "Kidney Diseases"

Urinary kallikrein excretion is known to increase in patients with nephrotic syndrome and sick cell disease, but decrease in patients with chronic kidney disease or uremia. Some of authors consider urinary kallikrein is a marker of nephropathy. To evaluate the possible role of kallikrein kinin system in chronic kidney disease, we conduct a retrospective longitudinal observation study. Patients who participating in the "Efficacy of Pentoxifylline on Chronic Kidney Disease" study are included in the study. The morning spot urinary kallikrein and cytokines are measured at the time point of 0 and 12 month in addition to clinical parameters. The correlation of urinary kallikrein and cytokine concentration will be evaluated. Using multiple regression model, the relationship of urinary kallikrein excretion with degree of proteinuria, creatinine clearance and other clinical parameter will also be evaluated.

This study will evaluate the effects of more frequent dialysis on cognitive function including the assessment of sleep apnea and restless legs. Our hypothesis is that more frequent dialysis improves cognitive function and may have important implications on clinical care of ESRD patients and help to emphasize the need for treatments that will allow patients to live "with dialysis" rather than live "for dialysis".

Parenteral iron therapy is now commonly administered to dialysis patients with the majority of patients receiving this therapy as part of the treatment for their anemia. Although intravenous iron has improved clinical response to recombinant erythropoietin, there is a concern that iron therapy may have deleterious effects in Chronic Kidney Disease (CKD) patients. Iron can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions that attack cellular proteins, DNA and membranes as part of oxidative stress. Numerous in vitro studies have shown tissue toxicity from iron and increased infectious potential. Oxidative stress can also lead to activation of the systemic inflammatory response with the release of a number of key cytokines and growth factors. There is now a link between inflammation, oxidative stress and acceleration of vascular disease in both patients with normal as well as reduced renal function. In a study comparing normal versus low hematocrit levels in hemodialysis patients, mortality was higher in the normal hematocrit group. The major difference between the two groups has been attributed to the fact that patients in the normal hematocrit group received significantly more iron than the patients with low hematocrit. There was a 2.4 fold greater mortality rate in patients receiving parenteral iron. The effect of parenteral iron administration on activation of the systemic inflammatory response in hemodialysis patients has not been evaluated. The purpose of this study is to measure a number of key cytokines, inflammatory and oxidative stress markers in hemodialysis patients receiving iron repletion therapy as part of their standard care.

Arterial stiffness refers to the accumulation of extracellular deposits of matrix and calcium which reduce blood vessel compliance. Although there is growing evidence that increased arterial stiffness is associated with chronic kidney disease (CKD), its pathogenesis is unclear. Pulse wave velocity (PWV) and augmentation index (AIx) provide tools for estimating arterial stiffness, and therefore predicting cardiovascular morbidity and mortality. The aims of the study are: (1) compare the effects of nocturnal and conventional haemodialysis on arterial stiffness, and (2) examine the relationship between arterial stiffness and clinical and biochemical parameters.

To determine whether the use of educational sessions and computerized clinical reminders can improve primary care doctors' delivery of care to CKD patients compared to educational sessions alone. Hypothesis: Clinical reminders will improve the care delivered to CKD patients

Background: Recent data indicate that home nocturnal hemodialysis (8 hours of hemodialysis at home for 5-6 nights per week) may have substantial cardiovascular benefits, including regression of left ventricular (LV) hypertrophy, improved LV ejection fraction and blood pressure control. Nevertheless, this dialysis modality is only feasible in a highly-selected minority of ESRD patients, who can self-manage their dialysis treatment at home. In-centre nocturnal hemodialysis (INHD), administered as 7-8 hours of hemodialysis in hospital for 3 nights per week, represents an appealing and practical alternative. As this is a novel form of therapy, there has been no definitive study examining the cardiovascular impact of INHD to date. Objective: To determine the effects of INHD on LV mass, global and regional systolic and diastolic function, and other cardiovascular biomarkers in patients with ESRD. Hypothesis: Conversion from conventional hemodialysis to INHD is associated with favourable changes in cardiac structure and function in patients with ESRD. Rationale for Using Cardiac MRI: Cardiac magnetic resonance imaging (CMR) has emerged as the new gold standard for measuring LV mass, volume, global and regional myocardial function. Its accuracy and precision make it the imaging modality of choice for studying the small number of patients currently undergoing or awaiting INHD. Study Design and Population: This is a prospective cohort study of adult ESRD patients who are currently receiving conventional in-centre hemodialysis and will be converted to INHD. Patients will be managed as per standard clinical practice (e.g. blood pressure, anemia management) established for the INHD program, and no therapeutic intervention will be performed as part of this study. All eligible patients will undergo two serial CMR examinations: within 2 weeks prior to conversion and at 52 weeks following conversion to INHD. We also plan to recruit a population of control patients who have elected to remain on conventional HD. These individuals will be asked to undergo the same set of investigations at baseline and 12 months thereafter. Outcome: The primary endpoints are the temporal changes in LV mass and size, global and regional diastolic and systolic function at 52 weeks after conversion to INHD, as measured by cardiac MRI. Secondary endpoints include changes in myocardial tissue characteristics, blood pressure, mineral metabolic parameters, anemia control, serum troponin, norepinephrine, brain natriuretic peptide, markers of inflammation and quality of life. Significance: The provision of an enhanced dialysis regimen has emerged as the most promising avenue through which to modify the dismal cardiovascular outcomes in patients receiving chronic hemodialysis. INHD represents a means of administering such therapy to a broad spectrum of dialysis patients for whom home therapies would not be feasible. The proposed study will be the first to precisely define the cardiac impact of INHD using CMR. The findings may justify large randomized controlled trials evaluating clinical outcomes. If INHD is proven to be effective, it will have a major impact on the management and outcome of many patients with ESRD in Canada.

It is our purpose in this study to compare the kidney structure and function of older patients to that of young patients before and after removal of a single kidney for transplant donation and to examine the remaining kidney's ability to adapt and maintain function over time. More specifically, we aim to examine the effect of uninephrectomy on adaptive hyperfiltration in the remaining kidney. A secondary aim is to investigate whether subjects in the aging population undergo compensation to the same extent as younger subjects. We will also examine the compensatory rise in GFR (glomerular filtration rate) that follows uninephrectomy in both groups, and, again, compare the results in the aged versus young subjects. This will help in delineating the extent to which the aging population can be a potential source of living kidney donors for kidney transplantation. It is also our purpose with this study to refine the tests to be used in the donor evaluation process so as to accurately identify ideal candidates for safe kidney donation.

The purpose of this study is to collect historical occurrences of risk factors that are potentially associated with the development of anti-erythropoietin (EPO) antibody positive pure red cell aplasia (PRCA) in participants with chronic kidney disease who have been recently treated with epoetin alfa (EPREX).

Kidney Disease Biomarkers Summary: This study will identify biomarkers (proteins and other molecules in the blood or urine) that may help scientists predict what kidney disease a patient has and whether a given patient would respond to particular therapies. The study will look for biomarkers in the blood and urine of patients with various kidney diseases and study of the effects of angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARB) on biomarkers. Blood and urine from healthy volunteers will be studied for comparison. Healthy people and the following patients may be eligible for this study: adults with diabetic nephropathy 18 years of age and older; children with newly diagnosed clinical idiopathic nephrotic syndrome between 2 and 18 year of age; children and adults with glomerular disease (minimal change disease, focal segmental glomerulosclerosis, or collapsing glomerulopathy). Participants undergo tests and procedures as follows: Glomerular Disease: Adults with glomerular disease provide about four to six blood and urine samples over the course of 6 to 12 months. The samples are collected at the time of regularly scheduled visits for the NIH treatment protocol in which they are participating. Children provide only blood samples. Chronic Kidney Disease: Patients with chronic kidney disease provide a blood and urine sample every 6 months for 3 years or more. Angiotensin Antagonism: Patients with chronic kidney disease who are taking ACE inhibitors or ARBs stop their medicines for 4 weeks, while those who are not taking ACE inhibitors or ARBs begin one of the medicines. In general, patients just starting on the medications continue them after the study is completed, since they are beneficial for chronic kidney disease. Medication withdrawal group: Patients come to NIH for 2 successive days at the beginning of the study for blood and urine tests (including one 24-hour urine collection) and to receive iothalamate (a chemical used to measure kidney function). Iothalamate is delivered over 24 hours through a needle placed in the abdomen (or elsewhere) via a pump similar to pumps that some diabetics use to deliver insulin. Patients then stop taking their ACE inhibitor or ARB medication. They monitor their blood pressure every day and return to NIH after 1, 2 and 4 weeks for blood tests. During week 4, the iothalamate infusion is repeated, and blood and urine samples are collected as at the beginning of the study. Patients then resume taking their ACE inhibitor or ARB once a day with the dose being increased at 2-week intervals. They come to NIH weekly after 1 week and then every other week for blood tests. Four weeks after reaching the highest FDA-recommended dose of medication tolerated, the iothalamate infusion and blood and urine collections are repeated. Medication induction group: At the beginning of the study, patients have the iothalamate infusion and blood and urine collections described above and then begin to take either an ACE inhibitor or ARB. The dose is increased after 2 weeks. Patients monitor their blood pressure every day. After being on the highest dose for 4 weeks, patients repeat the iothalamate infusion and blood and urine collections. The study is then complete and they are provided a 2-month supply of medicine to take home. Information is gathered on symptoms, treatments, and results of past laboratory tests of all patients. Healthy volunteers provide blood and urine sample collections every month or every other month for up to four collections to be used for biomarker studies and the screen for common chronic diseases.

This protocol facilitates the development of methods for determining whether transplant recipients have developed immune hyporesponsiveness or tolerance towards their allograft. These methods will involve the study of peripheral blood or biopsy tissue obtained at regular intervals from patients receiving kidney or combined kidney-pancreas allografts at the Warren G. Magnuson Clinical Center. In addition, patients that have previously received a kidney or combined kidney-pancreas allograft will be evaluated using assays requiring peripheral blood mononuclear cells and/or biopsies. Assays developed under this protocol will be used in subsequent protocols to assess the effects of immune modulating treatment regimens and may eventually be used to direct clinical care or guide the withdrawal of immunosuppressive agents. However, patients enrolled in this protocol will not have any change in treatment based solely on the assays developed without being enrolled in an additional study.