Water used to prepare haemodialysis fluid is not sterile, and its microbiological control is important for the prevention of haemodialysis-associated illness. Bacterial populations inhabiting a distribution system for haemodialysis water were studied over an 18-month period. 203 planktonic bacteria isolated on R2A medium were identified by restriction analysis and sequencing of 16S rRNA gene. A diverse bacterial community was detected, containing predominantly Gram-negative members of the Alphaproteobacteria and Betaproteobacteria, as well as representatives of the genus Mycobacterium. Ecological and clinical consequences are discussed: bacteria from the genera Novosphingobium, Pseudomonas and Sphingomonas have been described in the build-up of biofilms, and others like Acinetobacter, Mycobacterium or Brevibacterium may represent a health risk to patients under haemodialysis treatment.

It is desirable for patients to play active roles in the choice of renal replacement therapy (RRT). Patient decision aid tools (PDAs) have been developed to allow the patients to choose the option best suited to their individual needs. An observational, prospective registry was conducted in 26 Spanish hospitals between September 2010 and May 2012. The results of the patients’ choice and the definitive RRT modality were registered through the progressive implementation of an Education Process (EP) with PDAs designed to help Chronic Kidney Disease (CKD) patients choose RRT. Patients included in this study: 1044. Of these, 569 patients used PDAs and had made a definitive choice by the end of registration. A total of 88.4% of patients chose dialysis [43% hemodialysis (HD) and 45% peritoneal dialysis (PD)] 3.2% preemptive living-donor transplant (TX), and 8.4% conservative treatment (CT). A total of 399 patients began RRT during this period. The distribution was 93.4% dialysis (53.6% HD; 40% PD), 1.3% preemptive TX and 5.3% CT. The patients who followed the EP changed their mind significantly less often [kappa value of 0.91 (95% CI, 0.86–0.95)] than those who did not follow it, despite starting unplanned treatment [kappa value of 0.85 (95% CI, 0.75–0.95]. A higher agreement between the final choice and a definitive treatment was achieved by the EP and planned patients [kappa value of 0.93 (95% CI, 0.89–0.98)]. Those who did not go through the EP had a much lower index of choosing PD and changed their decision more frequently when starting definitive treatment [kappa value of 0.73 (95% CI, 0.55–0.91)]. Free choice, assisted by PDAs, leads to a 50/50 distribution of PD and HD choice and an increase in TX choice. The use of PDAs, even with an unplanned start, achieved a high level of concordance between the chosen and definitive modality.

Cardiovascular calcification (CVC) is a progressive complication of chronic kidney disease and a predictor of CV events and mortality. The use of biomarkers to predict CV risk and activities of potential or current treatment drugs in these patients could have a crucial impact on therapeutic approaches. Our aim was to develop a novel assay for measurement of the rate of calcium phosphate crystallization in human plasma and provide a tool to evaluate the effects of crystallization inhibitors. The efficacy of inhibitors was determined by adding inhibitory compounds (polyphosphates, fetuin-A, sodium thiosulfate or citrate) to control samples. The assay was additionally validated for SNF472, an experimental formulation of phytate being developed for the treatment of calciphylaxis and CVC in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). The method was repeatable and reproducible. The plasma crystallization rate was reduced up to 80% in a concentration-dependent manner following treatment with inhibitors in vitro, among which SNF472 was the most potent. This method appears beneficial in evaluating and discriminating between inhibitory activities of compounds such as polyphosphates on calcium phosphate crystallization, which present a novel therapeutic approach to treat CVC in ESRD patients.

Phytate, or myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate (InsP6), is a naturally occurring phosphorus compound that is present in many foods, mainly legumes, whole grains and nuts. Patients with chronic kidney disease (CKD) have cardiovascular disease mortality up to 30times higher than the general population. Vascular calcifications (VCs) directly contribute to overall morbidity and mortality, especially in CKD. In part, this high mortality is due to elevated levels of phosphorus in the blood. Therefore, control of dietary phosphorus is essential. Dietary phosphorus can be classified according to its structure in organic phosphorus (plant and animal) and inorganic (preservatives and additives). Plant-phosphorus (legumes and nuts), mainly associated with InsP6, is less absorbable by the human gastrointestinal tract as the bioavailability of phosphorous from plant-derived foods is very low. Recent data indicate that restriction of foods containing plant phosphates may compromise the adequate supply of nutrients that have a beneficial effect in preventing cardiovascular events, such as InsP6 or fibre found in legumes and nuts. Experimental studies in animals and observational studies in humans suggest that InsP6 can prevent lithiasis and VCs and protect from osteoporosis. In conclusion, we need prospective studies to elucidate the potential benefits and risks of phytate (InsP6) through the diet and as an intravenous drug in patients on haemodialysis.

The aim of this study of patients with chronic kidney disease (CKD) is to assess the safety of daily consumption of walnuts on the physiological levels of phosphorous, potassium, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23), and to assess the short-term benefits of this intervention on risk factors associated with cardiovascular events. This led us to perform a prospective, randomized, crossover, pilot clinical trial examined 13 patients with CKD. Subjects were randomly assigned to a diet of 30 g of walnuts per day or the control diet. After 30 days, each group was given a 30-day washout period, and then switched to the alternate diet for 30 days. Urinary and serum levels of phosphorous and potassium, multiple vascular risk factors, and urinary inositol phosphates (InsPs) were measured at baseline and at the end of the intervention period. Our results showed that the walnut dietary supplement led to reduced blood pressure, LDL cholesterol, and albumin excretion, but had no effect on the physiological levels of phosphorous, potassium, PTH, and FGF23. This is the first report to show that daily consumption of walnuts by patients with CKD does not alter their physiological levels of phosphorous, potassium, PTH, and FGF23 when included in a sodium-, protein-, phosphate-, and potassium-controlled diet, and it could be an effective strategy for reducing cardiovascular risk in patients with CKD.