Browsing by Subject "Chronic renal failure"

Now showing 1 - 4 of 4
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    Development of Therapies to Treat Polycystic Kidney Disease
    (2013-03-06) Flaig, Stephanie Marge; Blazer-Yost, Bonnie; Gattone II, Vincent H.; Belecky-Adams, Teri
    Polycystic kidney diseases (PKD) are genetic disorders characterized by fluid filled cysts in the kidney tubules and liver bile ducts. There are two forms of PKD, autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). The focus of the studies in this thesis has been on ADPKD. The disease progresses slowly and the fluid-filled cysts grow in size due to increased rates of cell proliferation and fluid secretion into the cyst lumen. The expanding cysts compromise the normal kidney function and result in a decrease of renal function to the point of end-stage renal failure in midlife. Cyst enlargement is due, at least in part, to chloride secretion via the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Currently therapy is limited to renal cyst aspiration, dialysis, and eventually renal transplantation after organ failure, thus it has critical to determine possible drug therapies for the treatment of PKD. Previous studies showed that cyst fluid caused a secretory response in cells lining the cysts. We hypothesized that once the cyst have expanded and become so large that they burst or leak, which could also occur due to renal injury or aging, the cyst fluid may stimulate additional cyst growth. Lysophosphatidic Acid (LPA) was determined to be the active component of human cyst fluid, and we investigated the LPA stimulated signaling pathway. Our data suggest that the LPA stimulates chloride and fluid secretion by a combination of CFTR and Calcium-Activated chloride channels (CaCC) and that the two channels may functionally be linked to each other. The secretion is not occurring through a cAMP stimulated pathway, and it is possible that TMEM16A, a CaCC, plays a larger role than previously expected. Previous studies demonstrated that PPARγ agonists, insulin sensitizing drugs used to treat diabetes, inhibit chloride secretion by the collecting duct principal cells by decreasing CFTR synthesis. It was logical therefore to considered PPARγ agonists as long-term treatment for PKD. The first preclinical studied showed that high (20 mg/kg BW) dose pioglitazone, a PPARγ agonist, inhibited cyst growth in the PCK rat model, a slow progressing model, of PKD. To continue to look at the effects of the PPARγ agonists another preclinical study was completed, which tested if there was a class action of PPARγ agonists and if a lower dose was effective in treating the cystic burden. Using the PCK rat model, and another PPARγ agonist, rosiglitazone, a 24 week study was completed using 3 doses (4, 0.4, and 0.04 mg/kg BW). 4 mg/kg BW rosiglitazone is analogous to 20 mg/kg BW pioglitazone. The data indicated that the rosiglitazone is effective in lowering the cystic burden, and importantly the low dose proved to be effective. An additional rat model, the W-WPK rapidly progressing model was used to determine efficacy across multiple models, and to determine if there was a way to track the progress of the disease in a manner analogous to that used in human patients. The animals were treated with pioglitazone using 2 doses (2 and 20 mg/kg BW), and were imaged using CT scans to track the progress of the disease. The data suggest that pioglitazone was not as effective in the W-WPK rat model as it was the PCK rat model. There was a trend however, that low dose PPARγ agonist was as effective ad high dose. Even more important, the CT scans proved to be an effective way to track the progress of the disease in animal models.
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    Methamphetamine (N-methylamphetamine)-induced renal disease: underevaluated cause of end-stage renal disease (ESRD)
    (BMJ, 2019-09-19) Baradhi, Krishna M.; Pathireddy, Samata; Bose, Subhasish; Aeddula, Narothama Reddy; Medicine, School of Medicine
    A 26-year-old Caucasian man with no medical history, except years of oral and intravenous drug abuse, presented with fatigue, shortness of breath, epistaxis and uncontrolled hypertension. He was pale with skin ecchymosis over his thighs and was anaemic, with severe renal failure and metabolic acidosis. Following initial clinical stabilisation of the patient, a renal biopsy was obtained, which showed vascular and glomerular changes consistent with thrombotic microangiopathic injury and advanced glomerulosclerosis. He was treated with antihypertensives and required haemodialysis. He admitted using ‘crystal meth’ regularly for many years, which is likely responsible for his renal failure. We present the case to illustrate methamphetamine-induced renal disease leading to end-stage renal disease and to bring awareness among practising clinicians, ancillary healthcare workers and public health professionals of this often undervalued cause of renal failure, which can be prevented.
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    Pentoxifylline in diabetic kidney disease (VA PTXRx): protocol for a pragmatic randomised controlled trial
    (BMJ, 2021-08-16) Leehey, David J.; Carlson, Kimberly; Reda, Domenic J.; Craig, Ian; Clise, Christina; Conner, Todd A.; Agarwal, Rajiv; Kaufman, James S.; Anderson, Robert J.; Lammie, Douglas; Huminik, Jeffrey; Polzin, Linda; McBurney, Conor; Huang, Grant D.; Emanuele, Nicholas V.; Medicine, School of Medicine
    Introduction: Diabetic kidney disease (DKD) is the most frequent cause of end-stage renal disease (ESRD) in the USA and worldwide. Recent experimental and clinical data suggest that the non-specific phosphodiesterase inhibitor pentoxifylline (PTX) may decrease progression of chronic kidney disease. However, a large-scale randomised clinical trial is needed to determine whether PTX can reduce ESRD and death in DKD. Methods and analysis: Veterans Affairs (VA) PTXRx is a pragmatic, randomised, placebo-controlled multicentre VA Cooperative Study to test the hypothesis that PTX, when added to usual care, leads to a reduction in the time to ESRD or death in patients with type 2 diabetes with DKD when compared with usual care plus placebo. The study aims to enrol 2510 patients over a 4-year period with an additional up to 5-year follow-up to generate a total of 646 primary events. The primary objective of this study is to compare the time until ESRD or death (all-cause mortality) between participants randomised to PTX or placebo. Secondary endpoints will be: (1) health-related quality of life, (2) time to doubling of serum creatinine, (3) incidence of hospitalisations for congestive heart failure, (4) incidence of a three-point major adverse cardiovascular events composite (cardiovascular death, non-fatal myocardial infarction, non-fatal stroke), (5) incidence of peripheral vascular disease, (6) change in urinary albumin-to-creatinine ratio from baseline to 6 months and (7) rate of annual change in estimated glomerular filtration rate (eGFR) during the study period. Ethics and dissemination: This study was approved by the VA Central Institutional Review Board (cIRB/18-36) and will be conducted in compliance with the Declaration of Helsinki and the Guidelines for Good Clinical Practice. The Hines Cooperative Studies Programme will finalise the study results, which will be published in accordance with the Consolidated Standards of Reporting Trials statement in a peer-reviewed scientific journal.
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    Should we CLICK on chlorthalidone for treatment-resistant hypertension in chronic kidney disease?
    (Oxford University Press, 2022-12-20) Agarwal, Rajiv; Medicine, School of Medicine
    Treatment-resistant hypertension is common among patients with advanced chronic kidney disease (CKD). In people with preserved kidney function, spironolactone is an evidence-based treatment. However, the risk for hyperkalemia limits its use in people with more advanced CKD. In the Chlorthalidone in Chronic Kidney Disease (CLICK) trial, 160 patients with stage 4 CKD and poorly controlled hypertension as confirmed by 24-hour ambulatory blood pressure (ABP) monitoring were randomly assigned to either placebo or chlorthalidone 12.5 mg daily in a 1:1 ratio stratified by prior loop diuretic use. The primary endpoint was the change in 24-hour systolic ABP from baseline to 12 weeks. The trial showed a treatment-induced reduction of 24-hour systolic ABP by 10.5 mmHg. Of the 160 patients randomized, 113 (71%) had resistant hypertension, of which 90 (80%) were on loop diuretics and the mean number of antihypertensive medications prescribed was 4.1 (standard deviation 1.1). In this subgroup of patients with treatment-resistant hypertension, the adjusted change from baseline to 12 weeks in the between-group difference in 24-hour systolic ABP was -13.9 mmHg (95% CI -19.4 to -8.4; P < .0001). Furthermore, compared with placebo, the urine albumin:creatinine ratio in the chlorthalidone group at 12 weeks was 54% lower (95% CI -65 to -40). Following randomization, hypokalemia, reversible increases in serum creatinine, hyperglycemia, dizziness, orthostatic hypotension and hyperuricemia occurred more frequently in the chlorthalidone group. Chlorthalidone has the potential to improve BP control among patients with advanced CKD and treatment-resistant hypertension. However, caution is advised when treating patients, especially when they are on loop diuretics.