Uremic Toxins and Inflammation: Metabolic Pathways Affected in Non-Dialysis-Dependent Stage 5 Chronic Kidney Disease.

Chronic kidney disease (CKD) affects approximately 12% of the global population, posing a significant health threat. Inflammation plays a crucial role in the uremic phenotype of non-dialysis-dependent (NDD) stage 5 CKD, contributing to elevated cardiovascular and overall mortality in affected individuals. This study aimed to explore novel metabolic pathways in this population using semi-targeted metabolomics, which allowed us to quantify numerous metabolites with known identities before data acquisition through an in-house polar compound library. In a prospective observational design with 50 patients, blood samples collected before the initial hemodialysis session underwent liquid chromatography and high-resolution mass spectrometer analysis. Univariate (Mann-Whitney test) and multivariate (logistic regression with LASSO regularization) methods identified metabolomic variables associated with inflammation. Notably, adenosine-5'-phosphosulfate (APS), dimethylglycine, pyruvate, lactate, and 2-ketobutyric acid exhibited significant differences in the presence of inflammation. Cholic acid, homogentisic acid, and 2-phenylpropionic acid displayed opposing patterns. Multivariate analysis indicated increased inflammation risk with certain metabolites (N-Butyrylglycine, dimethylglycine, 2-Oxoisopentanoic acid, and pyruvate), while others (homogentisic acid, 2-Phenylpropionic acid, and 2-Methylglutaric acid) suggested decreased probability. These findings unveil potential inflammation-associated biomarkers related to defective mitochondrial fatty acid beta oxidation and branched-chain amino acid breakdown in NDD stage 5 CKD, shedding light on cellular energy production and offering insights for further clinical validation.

Therapeutic approach in heart failure with poor diuretic response: peripheral ultrafiltration vs. conventional treatment.

AIMS: Patients with heart failure (HF) admitted for decompensation often require high doses of intravenous diuretics. This study aims to analyse whether the use of peripheral ultrafiltration (UF) in patients hospitalized for acute HF with systemic-predominant congestion results in better hydric control, renal protection, and reduction of hospital stay compared with conventional treatment. METHODS AND RESULTS: This study was a retrospective, comparative, single-centre study of 56 patients admitted for HF with systemic congestion with a poor diuretic response after diuretic escalation. One group underwent peripheral UF (35 patients) and others were maintained on intense diuretic treatment (control group, 21 patients). The diuretic response and days of hospital stay were compared between and within groups. The baseline characteristics of both groups were similar: males with right ventricular failure and renal dysfunction. The inter-group analysis showed that patients who received UF had better glomerular filtration rate (GFR; UF: 39.2 ± 18.2 vs. control: 28.7 ± 13.4 mL/min; P = 0.031) and higher diuresis (UF: 2184 ± 735 vs. control: 1335 ± 297 mL; P = 0.0001) at hospital discharge despite less need for diuretic drugs. Days of hospital stay were shorter in the UF group (UF: 11.7 ± 10.1 vs. control: 19.1 ± 14.4 days; P = 0.027). Intra-group analysis showed that patients receiving UF improved GFR, increased diuresis, and reduced weight at discharge (P < 0.001), whereas patients on conventional treatment only experienced improved weight but worsening renal function at discharge. CONCLUSIONS: In patients with acute HF with systemic congestion and diuretic resistance, UF compared with conventional treatment produces greater decongestion and renal protection, reduces the total diuretic load, and shortens the length of hospital stay.

The metabolomic differential plasma profile between dialysates. Pursuing to understand the mechanisms of citrate dialysate clinical benefits.

Background: Currently, bicarbonate-based dialysate needs a buffer to prevent precipitation of bicarbonate salts with the bivalent cations, and acetate at 3-4 mmol/L is the most used. However, citrate is being postulated as a preferred option because of its association with better clinical results by poorly understood mechanisms. In that sense, this hypothesis-generating study aims to identify potential metabolites that could biologically explain these improvements found in patients using citrate dialysate. Methods: A unicentric, cross-over, prospective untargeted metabolomics study was designed to analyze the differences between two dialysates only differing in their buffer, one containing 4 mmol/L of acetate (AD) and the other 1 mmol/L of citrate (CD). Blood samples were collected in four moments (i.e., pre-, mid-, post-, and 30-min-post-dialysis) and analyzed in an untargeted metabolomics approach based on UPLC-Q-ToF mass spectrometry. Results: The 31 most discriminant metabolomic variables from the plasma samples of the 21 participants screened by their potential clinical implications show that, after dialysis with CD, some uremic toxins appear to be better cleared, the lysine degradation pathway is affected, and branched-chain amino acids post-dialysis levels are 9-10 times higher than with AD; and, on its part, dialysis with AD affects acylcarnitine clearance. Conclusion: Although most metabolic changes seen in this study could be attributable to the dialysis treatment itself, this study successfully identifies some metabolic variables that differ between CD and AD, which raise new hypotheses that may unveil the mechanisms involved in the clinical improvements observed with citrate in future research.

Impact of Acetate versus Citrate Dialysates on Intermediary Metabolism-A Targeted Metabolomics Approach.

Acetate is widely used as a dialysate buffer to avoid the precipitation of bicarbonate salts. However, even at low concentrations that wouldn't surpass the metabolic capacity of the Krebs tricarboxylic acid (TCA) cycle, other metabolic routes are activated, leading to undesirable clinical consequences by poorly understood mechanisms. This study aims to add information that could biologically explain the clinical improvements found in patients using citrate dialysate. A unicentric, cross-over, prospective targeted metabolomics study was designed to analyze the differences between two dialysates, one containing 4 mmol/L of acetate (AD) and the other 1 mmol/L of citrate (CD). Fifteen metabolites were studied to investigate changes induced in the TCA cycle, glycolysis, anaerobic metabolism, ketone bodies, and triglyceride and aminoacidic metabolism. Twenty-one patients completed the study. Citrate increased during the dialysis sessions when CD was used, without surpassing normal values. Other differences found in the next TCA cycle steps showed an increased substrate accumulation when using AD. While lactate decreased, pyruvate remained stable, and ketogenesis was boosted during dialysis. Acetylcarnitine and myo-inositol were reduced during dialysis, while glycerol remained constant. Lastly, glutamate and glutarate decreased due to the inhibition of amino acidic degradation. This study raises new hypotheses that need further investigation to understand better the biochemical processes that dialysis and the different dialysate buffers induce in the patient's metabolism.

Safety and effectiveness of sucroferric oxyhydroxide in Spanish patients on dialysis: sub-analysis of the VERIFIE study.

BACKGROUND AND AIMS: In this study, we show the results of the subset of Spanish patients of the VERIFIE study, the first post-marketing study assessing the long-term safety and effectiveness of sucroferric oxyhydroxide (SFOH) in patients with hyperphosphatemia undergoing dialysis during clinical practice. PATIENTS AND METHODS: Patients undergoing hemodialysis and peritoneal dialysis with indication of SFOH treatment were included. Follow-up duration was 12-36 months after SFOH initiation. Primary safety variables were the incidence of adverse drug reactions (ADRs), medical events of special interest (MESIs), and variations in iron-related parameters. SFOH effectiveness was evaluated by the change in serum phosphorus levels. RESULTS: A total of 286 patients were recruited and data from 282 were analyzed. Among those 282 patients, 161 (57.1%) withdrew the study prematurely and 52.5% received concomitant treatment with other phosphate binders. ADRs were observed in 35.1% of patients, the most common of which were gastrointestinal disorders (77.1%) and mild/moderate in severity (83.7%). MESIs were reported in 14.2% of patients, and 93.7% were mild/moderate. An increase in ferritin (386.66ng/mL vs 447.55ng/mL; p=0.0013) and transferrin saturation (28.07% vs 30.34%; p=0.043) was observed from baseline to the last visit (p=0.0013). Serum phosphorus levels progressively decreased from 5.69mg/dL at baseline to 4.84mg/dL at the last visit (p<0.0001), increasing by 32.2% the proportion of patients who achieved serum phosphorus levels ≤5.5mg/dL, with a mean daily SFOH dose of 1.98 pills/day. CONCLUSIONS: SFOH showed a favorable effectiveness profile, a similar safety profile to that observed in the international study with most adverse events of mild/moderate severity, and a low daily pill burden in Spanish patients in dialysis.

Improvements in Inflammation and Calcium Balance of Citrate versus Acetate as Dialysate Buffer in Maintenance Hemodialysis: A Unicentric, Cross-Over, Prospective Study.

INTRODUCTION: The composition of the dialysate is a crucial feature in the dialysis treatment. Two of its most debated elements are the optimal calcium concentration and the use of acetate as a buffer. Moreover, among the different alternatives to achieve acetate-free dialysis, the use of citrate is postulated as the most suitable option. The objective of this study is to identify the potential beneficial effects of citrate when compared to acetate dialysate (AD) both in short-term effects (especially regarding intradialytic calcium balance and cardiac damage biomarkers) and in medium-term ones with CKD-mineral and bone disorder (CKD-MBD) and inflammatory biomarkers measured after twelve sessions performed with each dialysate. METHODS: This is a unicentric, cross-over, prospective study. Each patient underwent 24 dialysis sessions, 12 with each dialysate buffer. Blood samples were taken in 2 different sessions with each acidifier. They include CKD-MBD and inflammatory biomarkers. The calcium concentration of both dialysates was 1.5 mmol/L, while all other dialysis parameters and patients' treatment remained unchanged during the study period. RESULTS: When comparing AD and citrate dialysate (CD), there were no differences in pre-dialysis ionized calcium (iCa) (1.11 vs. 1.08 mmol/L) in both groups. However, there was a significant increase in iCa with the use of AD in immediate and 30-min post-dialysis blood samples. In contrast, iCa levels remained stable with the use of citrate. Inflammatory biomarkers were also reduced after the use of CD. CONCLUSIONS: The use of citrate provides interesting advantages when compared to acetate. It maintains iCa levels stable during dialysis sessions with a neutral or negative effect on calcium balance, and it improves the chronic inflammatory condition that comes with long-time hemodialysis treatment. These beneficial effects may lead to an improvement in clinical outcomes.

X-linked hypophosphatemic rickets: Diagnosis in adult and paucisymptomatic form. / Raquitismo hipofosfatémico ligado al cromosoma X: diagnóstico en la edad adulta y forma paucisintomática.

X-linked hypophosphataemic rickets (XLH) is the main form of hereditary rickets caused by mutation of the PHEX gene and occurs mainly in childhood. Clinically, it causes growth retardation and bone deformities; however, there are atypical forms of presentation that make diagnosis difficult. We present a case of XLH of late diagnosis and paucisymptomatic form with multiple fractures and greatly affecting quality of life, under treatment with traditional therapy for this disease.

[Results of a healthcare organization model for COVID-19 on hemodialysis in a tertiary hospital and its subsidized centers]. / Resultados de un modelo de organización asistencial para COVID-19 en hemodiálisis en un hospital terciario y sus centros concertados.

The experience of a tertiary hospital and four hemodialysis centers attached to it during the COVID-19 epidemic is described. The organization of care that has been carried out and the clinical course of the 16cases of COVID-19 in hemodialysis patients are summarized. The joint application of measures, including patient screening, the early investigation of possible cases, the isolation of confirmed, investigational or contact cases, as well as the use of individual protection measures, has enabled the epidemic to be controlled. The clinical course of these 16patients is compared with the series published by the Wuhan University Hospital and with the data from the COVID-19 infection registry of the Spanish Society of Nephrology. In our experience, and unlike what was reported by the Wuhan Center, COVID-19 disease in hemodialysis patients is severe in a significant percentage of cases, and high lethality is mostly caused by the infection itself. Measures to contain the epidemic are effective.