Browsing by Subject "Renal Insufficiency, Chronic"
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Item Bone marrow fat is increased in chronic kidney disease by magnetic resonance spectroscopy(Springer-Verlag, 2015-06) Moorthi, R. N.; Fadel, W.; Eckert, G. J.; Ponsler-Sipes, K.; Moe, S. M.; Lin, C.; Department of Medicine, IU School of MedicineIn aging, the bone marrow fills with fat and this may lead to higher fracture risk. We show that a bone marrow fat measurement by magnetic resonance spectroscopy (MRS), a newer technique not previously studied in chronic kidney disease (CKD), is useful and reproducible. CKD patients have significantly higher bone marrow fat than healthy adults. INTRODUCTION: Renal osteodystrophy leads to increased morbidity and mortality in patients with CKD. Traditional bone biopsy histomorphometry is used to study abnormalities in CKD, but the bone marrow, the source of osteoblasts, has not been well characterized in patients with CKD. METHODS: To determine the repeatability of bone marrow fat fraction assessment by MRS and water-fat imaging (WFI) at four sites in patients with CKD, testing was performed to determine the coefficients of reproducibility and intraclass coefficients (ICCs). We further determined if this noninvasive technique could be used to determine if there are differences in the percent bone marrow fat in patients with CKD compared to matched controls using paired t tests. RESULTS: The mean age of subjects with CKD was 59.8 ± 7.2 years, and the mean eGFR was 24 ± 8 ml/min. MRS showed good reproducibility at all sites in subjects with CKD and controls, with a coefficient of reproducibilities ranging from 2.4 to 13 %. MRS and WFI assessment of bone marrow fat showed moderate to strong agreement (ICC 0.6-0.7) at the lumbar spine, with poorer agreement at the iliac crest and no agreement at the tibia. The mean percent bone marrow fat at L2-L4 was 13.8 % (95 % CI 8.3-19.7) higher in CKD versus controls (p < 0.05). CONCLUSIONS: MRS is a useful and reproducible technique to study bone marrow fat in CKD. Patients with CKD have significantly higher bone marrow fat than healthy adults; the relationship with bone changes requires further analyses.Item BP Components in Advanced CKD and the Competing Risks of Death, ESRD, and Cardiovascular Events(American Society of Nephrology (ASN), 2015-06-05) Sinha, Arjun D.; Agarwal, Rajiv; Department of Medicine, IU School of MedicineItem Coupling fibroblast growth factor 23 production and cleavage: iron deficiency, rickets, and kidney disease(Ovid Technologies (Wolters Kluwer) - Lippincott Williams & Wilkins, 2014-07) Wolf, Myles; White, Kenneth E.; Department of Medical & Molecular Genetics, IU School of MedicinePURPOSE OF REVIEW: High levels of fibroblast growth factor 23 (FGF23) cause the rare disorders of hypophosphatemic rickets and are a risk factor for cardiovascular disease and death in patients with chronic kidney disease (CKD). Despite major advances in understanding FGF23 biology, fundamental aspects of FGF23 regulation in health and in CKD remain mostly unknown. RECENT FINDINGS: Autosomal dominant hypophosphatemic rickets (ADHR) is caused by gain-of-function mutations in FGF23 that prevent its proteolytic cleavage, but affected individuals experience a waxing and waning course of phosphate wasting. This led to the discovery that iron deficiency is an environmental trigger that stimulates FGF23 expression and hypophosphatemia in ADHR. Unlike osteocytes in ADHR, normal osteocytes couple increased FGF23 production with commensurately increased FGF23 cleavage to ensure that normal phosphate homeostasis is maintained in the event of iron deficiency. Simultaneous measurement of FGF23 by intact and C-terminal assays supported these breakthroughs by providing minimally invasive insight into FGF23 production and cleavage in bone. These findings also suggest a novel mechanism of FGF23 elevation in patients with CKD, who are often iron deficient and demonstrate increased FGF23 production and decreased FGF23 cleavage, consistent with an acquired state that mimics the molecular pathophysiology of ADHR. SUMMARY: Iron deficiency stimulates FGF23 production, but normal osteocytes couple increased FGF23 production with increased cleavage to maintain normal circulating levels of biologically active hormone. These findings uncover a second level of FGF23 regulation within osteocytes, failure of which culminates in elevated levels of biologically active FGF23 in ADHR and perhaps CKD.Item Francisella philomiragia Bacteremia in a Patient with Acute Respiratory Insufficiency and Acute-on-Chronic Kidney Disease(American Society for Microbiology, 2015-12) Relich, Ryan F.; Humphries, Romney M.; Mattison, H. Reid; Miles, Jessica E.; Simpson, Edward R.; Corbett, Ian J.; Schmitt, Bryan H.; May, M.; Department of Pathology & Laboratory Medicine, IU School of MedicineFrancisella philomiragia is a very uncommon pathogen of humans. Diseases caused by it are protean and have been reported largely in near-drowning victims and those with chronic granulomatous disease. We present a case of F. philomiragia pneumonia with peripheral edema and bacteremia in a renal transplant patient and review the diverse reports of F. philomiragia infections.Item Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease(Nature Publishing Group, 2013-05) Hill, Kathleen M.; Martin, Berdine R.; Wastney, Meryl; McCabe, George P.; Moe, Sharon M.; Weaver, Connie M.; Peacock, Munro; Department of Medicine, IU School of MedicineChronic kidney disease (CKD) patients are given calcium carbonate to bind dietary phosphorus and reduce phosphorus retention, and to prevent negative calcium balance. Data are limited on calcium and phosphorus balance in CKD to support this. The aim of this study was to determine calcium and phosphorus balance and calcium kinetics with and without calcium carbonate in CKD patients. Eight stage 3/4 CKD patients, eGFR 36 mL/min, participated in two 3-week balances in a randomized placebo-controlled cross-over study of calcium carbonate (1500 mg/d calcium). Calcium and phosphorus balance were determined on a controlled diet. Oral and intravenous 45calcium with blood sampling and urine and fecal collections were used for calcium kinetics. Fasting blood and urine were collected at baseline and end of each week of each balance period for biochemical analyses. Results showed that patients were in neutral calcium and phosphorus balance while on placebo. Calcium carbonate produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance suggesting tissue deposition. Fasting biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. If they can be extrapolated to effects of chronic therapy, these data caution against the use of calcium carbonate as a phosphate binder.Item Pathogenesis of Arrhythmias in a Model of CKD(American Society of Nephrology (ASN), 2014-12-01) Hsueh, Chia-Hsiang; Chen, Neal X.; Lin, Shien-Fong; Chen, Peng-Sheng; Gattone, Vincent H.; Allen, Matthew R.; Fishbein, Michael C.; Moe, Sharon M.; Department of Medicine, IU School of MedicinePatients with CKD have an increased risk of cardiovascular mortality from arrhythmias and sudden cardiac death. We used a rat model of CKD (Cy/+) to study potential mechanisms of increased ventricular arrhythmias. Rats with CKD showed normal ejection fraction but hypertrophic myocardium. Premature ventricular complexes occurred more frequently in CKD rats than normal rats (42% versus 11%, P=0.18). By optical mapping techniques, action potential duration (APD) at 80% of repolarization was longer in CKD rats (78±4ms) than normal rats (63±3 ms, P<0.05) at a 200-ms pacing cycle length. Calcium transient (CaT) duration was comparable. Pacing cycle length thresholds to induce CaT alternans or APD alternans were longer in CKD rats than normal rats (100±7 versus 80±3 ms and 93±6 versus 76±4 ms for CaT and APD alternans, respectively, P<0.05), suggesting increased vulnerability to ventricular arrhythmia. Ventricular fibrillation was induced in 9 of 12 CKD rats and 2 of 9 normal rats (P<0.05); early afterdepolarization occurred in two CKD rats but not normal rats. The mRNA levels of TGF-β, microRNA-21, and sodium calcium-exchanger type 1 were upregulated, whereas the levels of microRNA-29, L-type calcium channel, sarco/endoplasmic reticulum calcium–ATPase type 2a, Kv1.4, and Kv4.3 were downregulated in CKD rats. Cardiac fibrosis was mild and not different between groups. We conclude that cardiac ion channel and calcium handling are abnormal in CKD rats, leading to increased vulnerability to early afterdepolarization, triggered activity, and ventricular arrhythmias.Item Plasma apolipoprotein L1 levels do not correlate with CKD(American Society of Nephrology, 2014-03) Bruggeman, Leslie A.; O'Toole, John F.; Ross, Michael D.; Madhavan, Sethu M.; Smurzynski, Marlene; Wu, Kunling; Bosch, Ronald J.; Gupta, Samir; Pollak, Martin R.; Sedor, John R.; Kalayjian, Robert C.; Department of Medicine, IU School of MedicinePolymorphisms in APOL1 are associated with CKD, including HIV-related CKD, in individuals of African ancestry. The apolipoprotein L1 (APOL1) protein circulates and is localized in kidney cells, but the contribution of APOL1 location to CKD pathogenesis is unclear. We examined associations of plasma APOL1 levels with plasma cytokine levels, dyslipidemia, and APOL1 genotype in a nested case-control study (n=270) of HIV-infected African Americans enrolled in a multicenter prospective observational study. Patients were designated as having CKD when estimated GFR (eGFR) decreased to <60 ml/min per 1.73 m(2) (eGFR<60 cohort) or protein-to-creatinine ratios became >3.5 g/g (nephrotic proteinuria cohort). Circulating APOL1 levels did not associate with APOL1 genotype, CKD status, or levels of proinflammatory cytokines, but did correlate with fasting cholesterol, LDL cholesterol, and triglyceride levels. At ascertainment, CKD-associated polymorphisms (risk variants) in APOL1 associated with the eGFR<60 cohort, but not the nephrotic-range proteinuria cohort. Of note, in both the eGFR<60 and nephrotic proteinuria cohorts, CKD cases with two APOL1 risk variants had significant declines in eGFR over a median of 4 years compared with individuals with one or no risk variants. APOL1 risk genotype was not associated with changes in proteinuria. Higher circulating proinflammatory cytokine levels were independently associated with CKD but not APOL1 genotype. In conclusion, the function of variant APOL1 proteins derived from circulation or synthesized in the kidney, but not the level of circulating APOL1, probably mediates APOL1-associated kidney disease in HIV-infected African Americans.Item Raloxifene improves skeletal properties in an animal model of cystic chronic kidney disease(Nature Publishing Group, 2016-01) Newman, Christopher L.; Creecy, Amy; Granke, Mathilde; Nyman, Jeffry S.; Tian, Nannan; Hammond, Max A.; Wallace, Joseph M.; Brown, Drew M.; Chen, Neal; Moe, Sharon M.; Allen, Matthew R.; Department of Anatomy & Cell Biology, IU School of MedicinePatients with chronic kidney disease (CKD) have an increased risk of fracture. Raloxifene is a mild antiresorptive agent that reduces fracture risk in the general population. Here we assessed the impact of raloxifene on the skeletal properties of animals with progressive CKD. Male Cy/+ rats that develop autosomal dominant cystic kidney disease were treated with either vehicle or raloxifene for five weeks. They were assessed for changes in mineral metabolism and skeletal parameters (microCT, histology, whole-bone mechanics, and material properties). Their normal littermates served as controls. Animals with CKD had significantly higher parathyroid hormone levels compared with normal controls, as well as inferior structural and mechanical skeletal properties. Raloxifene treatment resulted in lower bone remodeling rates and higher cancellous bone volume in the rats with CKD. Although it had little effect on cortical bone geometry, it resulted in higher energy to fracture and modulus of toughness values than vehicle-treated rats with CKD, achieving levels equivalent to normal controls. Animals treated with raloxifene had superior tissue-level mechanical properties as assessed by nanoindentation, and higher collagen D-periodic spacing as assessed by atomic force microscopy. Thus, raloxifene can positively impact whole-bone mechanical properties in CKD through its impact on skeletal material properties.Item A randomized trial of intravenous and oral iron in chronic kidney disease(Nature Publishing Group, 2015-10) Agarwal, Rajiv; Kusek, John W.; Pappas, Maria K.; Department of Medicine, IU School of MedicineAlthough iron is commonly used to correct iron deficiency anemia (IDA) in chronic kidney disease (CKD), its effect on kidney function is unclear. To assess this, we randomly assigned patients with stage 3 and 4 CKD and IDA to either open-label oral ferrous sulfate (69 patients to 325 mg three times daily for 8 weeks) or intravenous iron sucrose (67 patients to 200 mg every 2 weeks, total 1 g). The primary outcome was the between-group difference in slope of measured glomerular filtration rate (mGFR) change over two years. The trial was terminated early on the recommendation of an independent data and safety monitoring board based on little chance of finding differences in mGFR slopes, but a higher risk of serious adverse events in the intravenous iron treatment group. mGFR declined similarly over two years in both treatment groups (oral -3.6 ml/min per 1.73 m(2), intravenous -4.0 ml/min per 1.73 m(2), between-group difference -0.35 ml/min per 1.73 m(2); 95% confidence interval -2.9 to 2.3). There were 36 serious cardiovascular events among 19 participants assigned to the oral iron treatment group and 55 events among 17 participants of the intravenous iron group (adjusted incidence rate ratio 2.51 (1.56-4.04)). Infections resulting in hospitalizations had a significant adjusted incidence rate ratio of 2.12 (1.24-3.64). Thus, among non-dialyzed patients with CKD and IDA, intravenous iron therapy is associated with an increased risk of serious adverse events, including those from cardiovascular causes and infectious diseases.Item Rebasing the Medicare payment for dialysis: rationale, challenges, and opportunities(American Society of Nephrology (ASN), 2014-12-05) Wish, Diane; Johnson, Doug; Wish, Jay; Department of Medicine, IU School of MedicineAfter Medicare's implementation of the bundled payment for dialysis in 2011, there has been a predictable decrease in the use of intravenous drugs included in the bundle. The change in use of erythropoiesis-stimulating agents, which decreased by 37% between 2007, when its allowance in the bundle was calculated, and 2012, was because of both changes in the Food and Drug Administration labeling for erythropoiesis-stimulating agents in 2011 and cost-containment efforts at the facility level. Legislation in 2012 required Medicare to decrease (rebase) the bundled payment for dialysis in 2014 to reflect this decrease in intravenous drug use, which amounted to a cut of 12% or $30 per treatment. Medicare subsequently decided to phase in this decrease in payment over several years to offset the increase in dialysis payment that would otherwise have occurred with inflation. A 3% reduction from the rebasing would offset an approximately 3% increase in the market basket that determines a facility's costs for 2014 and 2015. Legislation in March of 2014 provides that the rebasing will result in a 1.25% decrease in the market basket adjustment in 2016 and 2017 and a 1% decrease in the market basket adjustment in 2018 for an aggregate rebasing of 9.5% spread over 5 years. Adjusting to this payment decrease in inflation-adjusted dollars will be challenging for many dialysis providers in an industry that operates at an average 3%-4% margin. Closure of facilities, decreases in services, and increased consolidation of the industry are possible scenarios. Newer models of reimbursement, such as ESRD seamless care organizations, offer dialysis providers the opportunity to align incentives between themselves, nephrologists, hospitals, and other health care providers, potentially improving outcomes and saving money, which will be shared between Medicare and the participating providers.