Stable Renal Failure Research Articles

Renoprotective effects of sucroferric oxyhydroxide in a rat model of chronic renal failure.

IntroductionSucroferric oxyhydroxide (PA21) is an efficacious, well-tolerated iron-based phosphate binder and a promising alternative to existing compounds. We compared the effects of PA21 with those of a conventional phosphate binder on renal function, mineral homeostasis and vascular calcification in a chronic kidney disease–mineral and bone disorder (CKD-MBD) rat model.MethodsTo induce stable renal failure, rats were administered a 0.25% adenine diet for 8 weeks. Concomitantly, rats were treated with vehicle, 2.5 g/kg/day PA21, 5.0 g/kg/day PA21 or 3.0 g/kg/day calcium carbonate (CaCO3). Renal function and calcium/phosphorus/iron metabolism were evaluated during the study course. Renal fibrosis, inflammation, vascular calcifications and bone histomorphometry were quantified.ResultsRats treated with 2.5 or 5.0 g/kg/day PA21 showed significantly lower serum creatinine and phosphorus and higher ionized calcium levels after 8 weeks of treatment compared with vehicle-treated rats. The better preserved renal function with PA21 went along with less severe anaemia, which was not observed with CaCO3. Both PA21 doses, in contrast to CaCO3, prevented a dramatic increase in fibroblast growth factor (FGF)-23 and significantly reduced the vascular calcium content while both compounds ameliorated CKD-related hyperparathyroid bone.ConclusionsPA21 treatment prevented an increase in serum FGF-23 and had, aside from its phosphate-lowering capacity, a beneficial impact on renal function decline (as assessed by the renal creatinine clearance) and related disorders. The protective effect of this iron-based phosphate binder on the kidney in rats, together with its low pill burden in humans, led us to investigate its use in patients with impaired renal function not yet on dialysis.

Detection of autosomal dominant polycystic kidney disease by NMR spectroscopic fingerprinting of urine

Autosomal dominant polycystic kidney disease (ADPKD) is a frequent cause of kidney failure; however, urinary biomarkers for the disease are lacking. In a step towards identifying such markers, we used multidimensional-multinuclear nuclear magnetic resonance (NMR) spectroscopy with support vector machine-based classification and analyzed urine specimens of 54 patients with ADPKD and slightly reduced estimated glomerular filtration rates. Within this cohort, 35 received medication for arterial hypertension and 19 did not. The results were compared with NMR profiles of 46 healthy volunteers, 10 ADPKD patients on hemodialysis with residual renal function, 16 kidney transplant patients, and 52 type 2 diabetic patients with chronic kidney disease. Based on the average of 51 out of 701 NMR features, we could reliably discriminate ADPKD patients with moderately advanced disease from ADPKD patients with end-stage renal disease, patients with chronic kidney disease of other etiologies, and healthy probands with an accuracy of >80%. Of the 35 patients with ADPKD receiving medication for hypertension, most showed increased excretion of proteins and also methanol. In contrast, elevated urinary methanol was not found in any of the control and other patient groups. Thus, we found that NMR fingerprinting of urine differentiates ADPKD from several other kidney diseases and individuals with normal kidney function. The diagnostic and prognostic potential of these profiles requires further evaluation.

Assessing the blood volume and heart rate responses during haemodialysis in fluid overloaded patients using support vector regression

This study aims to assess the blood volume and heart rate (HR) responses during haemodialysis in fluid overloaded patients by a nonparametric nonlinear regression approach based on a support vector machine (SVM). Relative blood volume (RBV) and electrocardiogram (ECG) was recorded from 23 haemodynamically stable renal failure patients during regular haemodialysis. Modelling was performed on 18 fluid overloaded patients (fluid removal of >2 L). SVM-based regression was used to obtain the models of RBV change with time as well as the percentage change in HR with respect to RBV. Mean squared error (MSE) and goodness of fit (R2) were used for comparison among different kernel functions. The design parameters were estimated using a grid search approach and the selected models were validated by a k-fold cross-validation technique. For the model of HR versus RBV change, a radial basis function (RBF) kernel (MSE = 17.37 and R2 = 0.932) gave the least MSE compared to linear (MSE = 25.97 and R2 = 0.898) and polynomial (MSE = 18.18 and R2= 0.929). The MSE was significantly lower for training data set when using RBF kernel compared to other kernels (p < 0.01). The RBF kernel also provided a slightly better fit of RBV change with time (MSE = 1.12 and R2 = 0.91) compared to a linear kernel (MSE = 1.46 and R2 = 0.88). The modelled HR response was characterized by an initial drop and a subsequent rise during progressive reduction in RBV, which may be interpreted as the reflex response to a transition from central hypervolaemia to hypovolaemia. These modelled curves can be used as references to a controller that can be designed to regulate the haemodynamic variables to ensure the stability of patients undergoing haemodialysis.

RECENT ADVANCES IN THE MANAGEMENT OF HEPATO-RENAL SYNDROME (HRS)

Hepato-renal syndrome (HRS) is a functional renal failure complicating end-stage liver disease. HRS is characterized by marked arterial vasodilation (mainly of the splanchnic bed) and severe renal vasoconstriction. HRS is classified into 2 types: type I HRS shows a rapid and progressive decline in renal function with a very poor prognosis (median survival of about 2 weeks); HRS type 2 has a more stable renal failure, with a median survival of about 6 months. The management of HRS is still a big challenge. The definitive therapy for HRS is liver transplantation (LT); however, the survival rate of HRS patients is poor, and important organ shortage exists. Various approaches have been used for HRS treatment including vasoconstrictor therapy. Recent evidence has shown that vasoconstrictor agents are effective and serve as a bridge to LT; the rationale for vasoconstrictors is to counteract the splanchnic arterial vasodilation and increase the effective arterial blood volume. Thus, renal perfusion and glomerular filtration rates improve. Terlipressin, a V1 vasopressin agonist, has been used frequently. A recent meta-analysis of clinical trials showed that the pooled rate of patients who reversed HRS after terlipressin therapy was 0.52 (95% CI, 0.42; 0.61; P=0.0001, I2=24.6%). The pooled Odds Ratio (OR) for mortality rate in HRS patients who were not responders to terlipressin versus responders was 5.746 (95% CI, 1.5; 21.9; P=0.0005). Prospective, controlled clinical trials are in progress to address the impact of vasoconstrictor use on survival in HRS patients. Alternative therapies such as transjugular intrahepatic portosystemic shunts (TIPS) and extracorporeal albumin dialysis (ECAD) have given encouraging results but experience is extremely limited.

Local and Systemic Complications in a Cat after Poorly Performed Dental Extractions

This case report describes a cat that was presented with infected oral tissues and signs of systemic inflammatory response. Incomplete dental extractions had been performed 10-days earlier During a second dental procedure, 22 tooth root remnants were removed. Diabetic ketoacidosis and possible thromboembolism complicated the cat's recovery period After 13-days of hospitalization, the patient was stable enough to be sent home. Postoperative examinations at 1, 3, 6, 12, 16, 24, and 52-weeks indicated continued improvement with moderate glycemic control and chronic but stable renal failure. The patient died from further complications of diabetic ketoacidosis 20-months following root remnant extractions.

Gender as a risk factor for contrast nephropathy: Effects of hydration and N‐acetylcysteine

In a few studies, N-acetylcysteine has been shown to prevent contrast-induced nephropathy in patients with chronic, stable renal failure undergoing elective procedures. Other studies have shown variable outcomes. Furthermore, the majority of prior studies have mainly studied men, and gender as a risk factor has not been studied. The study sought to evaluate the effectiveness of N-acetylcysteine and hydration in unselected patients with both acute and stable renal insufficiency (RI) undergoing urgent or elective cardiac or peripheral angiography. We evaluated records of 146 patients with RI undergoing angiography. We compared patients receiving periprocedure hydration and acetylcysteine with patients who were only hydrated or received no pretreatment. We evaluated the 48-h change in serum creatinine between groups and further analyzed the effect of hydration and gender on outcomes. Demographics and baseline creatinine were similar between groups. Post procedure, the creatinine increased significantly in both groups, but less so in the acetylcysteine group (control: 0.35 +/- 0.08 mg/dl; acetylcysteine: 0.14 +/- 0.04 mg/dl, p < 0.05). When the control group was further stratified by hydration, the increase in creatinine for the hydrated patients was only 0.17 +/- 0.10 mg/dl compared with 0.54 +/- 0.12 mg/dl in patients with inadequate hydration. In the control group, women were more likely to receive no preprocedural hydration (59 vs. 40%), had a bigger rise in creatinine, received less protection from hydration alone, but were equally well protected by hydration plus acetylcysteine. In the acetylcysteine group, change in creatinine for women was minimal (+ 0.14 +/- 0.07 mg/dl) and not different from men (+ 0.15 +/- 0.05). Unselected patients with acute and chronic RI had no benefit from acetylcysteine beyond that seen with hydration alone. Gender may be a risk factor for contrast-induced nephropathy, with hydration offering less protection in women. Acetylcysteine (with hydration) seems to minimize the gender difference.

Primary focal segmental glomerulosclerosis in children: prognostic factors.

To study the clinical course and the predictors of outcome in children and adolescents, 39 patients with nephrotic syndrome and primary focal segmental glomerulosclerosis (FSGS) were followed for a mean of 84.6 months. Thirty-six patients were treated with prednisone, either alone or in conjunction with cyclophosphamide. The clinical course was one of sustained remission in 4 patients, frequent relapse in 13, persistent nonnephrotic proteinuria in 5, and persistent nephrotic syndrome in 17; 2 patients had stable renal failure and 8 had progressive renal failure, 5 of them evolving to end-stage renal failure (ESRF). Resistance to prednisone was recorded in 76.6% of patients. The use of cyclophosphamide plus prednisone was of benefit in 42.8% of patients; 22.2% of the prednisone-resistant patients achieved remission of the nephrotic syndrome. A Kaplan-Meier analysis revealed a survival rate of 92% after 5 years, 86% after 10 years, and 76% after 15 years. Using both univariate and multivariate analysis, persistent nephrotic syndrome was associated with progression to ESRF and the remission of proteinuria with maintenance of renal function. As the outcome of the nephrotic syndrome in FSGS is significantly improved by remission of proteinuria, it is conceivable that immunosuppressive medication may be used in conjunction with prednisone in patients with steroid resistance.

Calcium acetate versus calcium carbonate: Phosphate absorption studies in chronic renal failure

Summary: The aim of this study was to compare the alimentary phosphate‐binding capacity of calcium acetate to calcium carbonate in stable chronic renal failure patients who were not on haemodialysis. Intestinal absorption of phosphate and calcium was measured on three occasions in five patients with chronic renal failure who were not on maintenance haemodialysis. During each test period they received either no drug, calcium carbonate or calcium acetate (both containing 1g elemental calcium) in a randomized manner, along with a standardized meal. Intestinal contents were recovered after 10h by whole gut lavage, and phosphorus and calcium measured in meal and intestinal contents. Faecal excretion of ingested phosphorus increased from 13.85% in the absence of drug to 29.91% after calcium carbonate administration. Phosphorus excretion was significantly higher after calcium acetate (43.92%) compared to calcium carbonate (P&lt;0.05). Less calcium was absorbed from calcium acetate than from equimolar amounts of calcium caronate (P&lt;0.05). In patients with stable renal failure, calcium acetate is a better alimentary phosphate binder than calcium carbonate and binds more phosphorus for each mol of calcium absorbed.

Lack of Relationship between Parathyroid Hormone and 1,25-Dihydroxyvitamin D in Chronic Renal Failure

In the present study, concentrations of parathyroid hormone (PTH), determined by an intact PTH assay and a midregion/C-terminal PTH assay, 1,25-dihydroxyvitamin D [1,25(OH)2D3], ionized calcium and phosphate were measured in 15 patients with a stable creatinine clearance (Ccr) of 21.2 +/- 14.4 ml/min (mean +/- SD; group 1) and in 10 patients with a Ccr regularly undergoing hemodialysis (group 2, Ccr not measured). In group 1, the mean concentration of 1,25(OH)2D3 was significantly increased compared with the level in group 2, whereas no differences were found concerning the concentrations of intact PTH, midregion/C-terminal PTH, ionized calcium and phosphate. In group 1, the PTH concentration correlated inversely with ionized calcium concentration and Ccr, which in turn, was directly correlated. The concentration of 1,25(OH)2D3 correlated inversely with phosphate concentration, but did not correlate with either PTH or ionized calcium concentrations. In group 2 no correlation was found between any of the biochemical variables. The data demonstrate that in patients with stable renal failure, the concentration of ionized calcium still regulates PTH secretion but other variables such as parathyroid cell mass and setpoint may interfere with the interrelation. The elevated concentration of phosphate in renal failure may override PTH as a regulator of the renal 1,25(OH)2D3 formation. The lack of correlation in the hemodialyzed patients may be attributed to extrarenal production of 1,25(OH)2D3, reduced binding of 1,25(OH)2D3 to parathyroid tissue or the major changes in calcium homeostasis caused by the hemodialysis.

Pharmacokinetics of piperacillin in patients with moderate renal failure and in patients undergoing hemodialysis.

The pharmacokinetics of piperacillin administered intravenously were studied in five patients with stable mild to moderate renal impairment and in five patients undergoing hemodialysis. Patients with stable renal failure given 1 g of piperacillin intravenously had peak serum concentrations within 30 min ranging from 78 to 280 micrograms/ml. The mean serum half-life was 3.57 +/- 1.36 h; the mean apparent volume of distribution was 28.6 +/- 13.5 liters/100 kg; and the plasma clearance was 4.10 +/- 1.46 liters/h per 1.73 m2. Neither serum half-life nor clearance correlated with serum creatinine, implying significant nonrenal elimination. Patients undergoing hemodialysis had peak serum concentrations within 30 min of 66 to 138 micrograms/ml after 1 g of piperacillin infused intravenously. During hemodialysis, the serum half-life was 3.6 +/- 2.5 h; the mean apparent volume of distribution was 26.7 +/- 16.7 liters/100 kg; and the plasma clearance was 3.28 +/- 0.76 layers/h per 1.73 m2. Mean hemodialysis clearance was 0.484 +/- 0.282 liters/h per 1.73 m2, and only 10.0 +/- 5.3% of the total dose could be recovered in the dialysate.

Steady-state Kinetics and Dosage Requirements of Cimetidine in Renal Failure

25 patients with different degrees of chronic stable renal failure received oral treatment with cimetidine over 6 days and a final dose in the morning of day 7. The doses of cimetidine were reduced according to the degree of renal failure. Plasma concentrations of cimetidine were determined before the morning dose on days 2,3,6 and before the final morning dose and during the day on day 7. 24-hour excretions of cimetidine were measured during the study and on day 7, 6 to 9 hours after the final morning dose. There were significant linear relationships between the values of creatinine clearance and plasma elimination rate constant of cimetidine (p less than 0.0025) and between the values of creatinine clearance and renal clearance of cimetidine (p less than 0.05). On the basis of the morning plasma concentrations before and the plasma concentration curve after the final morning dose on day 7 the following dose recommendations according to pretrial values of creatinine clearance are recommended for cimetidine treatment in renal failure: 5 to 15ml/min 200mg 2 or 3 times daily, 15 to 30ml/min 200mg 3 times daily and 30 to 75ml/min 200mg 4 times daily.

Aminoaciduria in chronic renal failure--its relationship to vitamin D and parathyroid status

Fractional clearances of amino acids in 24 patients with chronic renal failure indicate that aminoaciduria is common and often severe. Eleven studies have also been carried out in ten patients with stable renal failure before and during treatment with different metabolites of vitamin D. Sequential measurements of fractional clearance of amino acids, plasma 25-hydroxy-vitamin D (25-(OH)D) and serum parathyroid hormone were made. All patients initially had hyperaminoaciduria, secondary hyperparathyroidism and osteomalacia. Treatment with 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) or 1 alpha-hydroxycholecalciferol (1 alpha(OH)D3) significantly improved amino acid reabsorption irrespective of the initial degree of aminoaciduria. Cholecalciferol or 25-hydroxycholecalciferol(25(OH)D3) improved amino acid transport in patients with initially mild hyperaminoaciduria, but not in patients with severe hyperaminoaciduria. Reduction in aminoaciduria during treatment with 25(OH)D3 may have depended on a variable ability to synthesize 1,25(OH)2D3. Changes in amino acid transport did not correlate with changes in serum parathyroid hormone. It is suggested that defective amino acid reabsorption in patients with chronic renal failure is due at least in part to deficiency of 1,25(OH)2D3.

Effects of triiodothyronine on the anemia of chronic renal failure.

The present study was done in order to determine whether treatment with triiodothyronine (T3) would improve the anemia of chronic renal insufficiency. Four patients with stable renal failure and anemia were treated with 75 microgram/day of T3 for a period of four weeks. The patients were not in chronic dialysis, had normochromic normocytic anemia and hypocellular bone marrow, and showed no evidence of external blood loss during the study. They had received no iron, folic acid, or androgenic steroids for at least six months prior to the study. The administered dose of T3 was adequate to depress the serum levels of thyroid-stimulating hormone (TSH); however, there was no detectable improvement in the levels of hemoglobin, hematocrit, bone marrow cellularity, serum and erythrocyte folate determinations, serum iron (Fe), 59Fe half-life, plasma iron turnover rate, percentage Fe incorporated into red blood cells, or in the ratio of surface radioactive counting over bone marrow/liver and spleen. It is concluded that the experimental observations concerning direct bone marrow stimulation by T3 in anephric rats are probably not clinically applicable for the treatment of the anemia associated with uremia.

Pharmacokinetics of cefamandole in patients with renal failure.

The pharmacokinetics of cefamandole were studied in four patients with stable renal failure, two patients undergoing peritoneal dialysis, and four patients undergoing hemodialysis. Peak concentrations of cefamandole in serum were achieved 1 to 2 h after intramuscular injection in the patients with stable renal impairment, and the concentrations declined slowly, with half-life values of 12.3 to 18 h. Cefamandole was removed only very slowly by peritoneal dialysis. Hemodialysis was more efficient in removing cefamandole, with serum half-life values ranging from 3.8 to 7.9 h. The mean apparent volume of distribution of cefamandole in these 10 patients was 21.92 liters, or 31% of the body weight.

Pancreatitis and Renal Disease

Pancreatitis has been described previously following renal transplantation, but not in association with chronic renal failure. Analysis of 168 patients with renal transplants revealed five who developed pancreatitis, three of whom died. All five were on treatment with prednisone and azathioprine. Four patients were seen with definite attacks of pancreatitis and chronic, stable renal failure from a variety of causes. None had received immunosuppressive agents, prednisone nor thiazide diuretics, but two were on regular frusemide. One patient was on maintenance dialysis, which could not be related directly to the pancreatitis. In either group alcohol ingestion, cholethiathiasis, or hypercalcaemia was not a factor. This diagnosis of pancreatitis was established on clinical grounds and serum amylast levels of greater than 900 iu/1. Similar serum amylast elevation was not found ina random group of patients with chronic renal failure. Hyperlipidaemia was not present in any patient with pancreatitis. Although hypercalcaemia and primary hyperparathyroidism was not found in the transplant and non-transplant subjects, elevated serum parathormone levels have been described in uraemic patients with normocalcaemia. Hyperparathyroidism may be a factor in the development of pancreatitis in reanl failure. Pancreatitis carries a significant mortality risk in renal transplantation. The four non-transplanted patients have survived, despite recurrent attacks of pancreatitis.

Pharmacokinetics of cefamandole in the presence of renal failure in patients undergoing hemodialysis.

The pharmacology of cefamandole in seven patients with stable renal insufficiency and in eight patients undergoing hemodialysis was determined. All patients had creatinine clearances less than 5 ml/min. The half-life of cefamandole in those patients with stable chronic renal failure was 7.7 +/- 2.2 h. The mean venous level 1 h after intravenous injection of a 1-g dose was 85.3 +/- 32.0 mug/ml. The mean venous half-life of cefamandole during hemodialysis was 6.1 h. The venous serum level after 5.5 of hemodialysis was 50.4 +/- 20.8 mug/ml. The mean coefficient of extraction was 0.155, and the mean clearance was 34.7 ml/min. The time interval between doses of cefamandole administered intravenously should be lengthened to 24 h in the presence of stable renal failure. No major change in dosage schedule is necessary for patients undergoing dialysis.