Poor neutralization and rapid decay of antibodies to SARS-CoV-2 variants in vaccinated dialysis patients.

Patients on dialysis are at risk of severe course of SARS-CoV-2 infection. Understanding the neutralizing activity and coverage of SARS-CoV-2 variants of vaccine-elicited antibodies is required to guide prophylactic and therapeutic COVID-19 interventions in this frail population. By analyzing plasma samples from 130 hemodialysis and 13 peritoneal dialysis patients after two doses of BNT162b2 or mRNA-1273 vaccines, we found that 35% of the patients had low-level or undetectable IgG antibodies to SARS-CoV-2 Spike (S). Neutralizing antibodies against the vaccine-matched SARS-CoV-2 and Delta variant were low or undetectable in 49% and 77% of patients, respectively, and were further reduced against other emerging variants. The fraction of non-responding patients was higher in SARS-CoV-2-naïve hemodialysis patients immunized with BNT162b2 (66%) than those immunized with mRNA-1273 (23%). The reduced neutralizing activity correlated with low antibody avidity. Patients followed up to 7 months after vaccination showed a rapid decay of the antibody response with an average 21- and 10-fold reduction of neutralizing antibodies to vaccine-matched SARS-CoV-2 and Delta variant, which increased the fraction of non-responders to 84% and 90%, respectively. These data indicate that dialysis patients should be prioritized for additional vaccination boosts. Nevertheless, their antibody response to SARS-CoV-2 must be continuously monitored to adopt the best prophylactic and therapeutic strategy.

A Pilot Observational Study Assessing Long-Term Changes in Clinical Parameters, Functional Capacity and Fall Risk of Patients With Chronic Renal Disease Scheduled for Hemodialysis.

BACKGROUND: Patients with end-stage renal disease are known to be particularly frail, and the cause is still widely seen as being directly related to specific factors in renal replacement therapy. However, a closer examination of the transitional phase from predialysis to long-term hemodialysis leads to controversial explanations, considering that the frailty process is already well-described in the early stages of renal insufficiency. This study aims to describe longitudinally and multifactorially changes in the period extending from the decision to start the replacement therapy through to the end of 2 years of hemodialysis. We hypothesized that frailty is pre-existent in the predialysis phase and does not worsen with the beginning of the replacement therapy. Between 2015 and 2018 we recruited 25 patients (72.3 ± 5.7 years old) in a predialysis program, with the expectation that replacement therapy would begin within the coming few months. METHODS: The patients underwent a baseline visit before starting hemodialysis, with 4 follow-up visits in the first 2 years of treatment. Health status, physical performance, cognitive functioning, hematology parameters, and adverse events were monitored during the study period. RESULTS: At baseline, our sample had a high variability with patients ranging from extremely frail to very fit. In the 14 participants that did not drop out of the study, out of 32 clinical and functional measures, a statistically significant worsening was only observed in the Short Physical Performance Battery (SPPB) score (p < 0.01, F = 8.50) and the number of comorbidities (p = 0.01, F = 3.94). A careful analysis, however, reveals a quite stable situation in the first year of replacement therapy, for both frail and fit participants and a deterioration in the second year that in frail participants could lead to death. CONCLUSION: Our results should stimulate a reassessment about the role of a predialysis program in reducing complications during the transitional phase, but also about frailty prevention programs once hemodialysis has begun, for both frail and fit patients, to maintain satisfactory health status.

Consequences of Supraphysiological Dialysate Magnesium on Arterial Stiffness, Hemodynamic Profile, and Endothelial Function in Hemodialysis: A Randomized Crossover Study Followed by a Non-Controlled Follow-Up Phase.

INTRODUCTION: Increasing dialysate magnesium (D-Mg2+) appears to be an intriguing strategy to obtain cardiovascular benefits in subjects with end-stage kidney disease (ESKD) on hemodialysis. To date, however, hemodialysis guidelines do not suggest to increase D-Mg2+ routinely set at 0.50 mmol/L. METHODS: A randomized 4-week crossover study aimed at investigating the consequences of increasing D-Mg2+ from 0.50 to 0.75 mmol/L on arterial stiffness, hemodynamic profile, and endothelial function in subjects undergoing hemodialysis. The long-term effect of higher D-Mg2+ on mineral metabolism markers was investigated in a 6-month follow-up. Data were analyzed by linear mixed models for repeated measures. RESULTS: Data of 39 patients were analyzed. Pulse wave velocity and pulse pressure significantly decreased on the higher D-Mg2+ compared with the standard one by - 0.91 m/s (95% confidence interval - 1.52 to - 0.29; p = 0.01) and - 9.61 mmHg (- 18.89 to - 0.33, p = 0.04), respectively. A significant reduction in systolic blood pressure of - 12.96 mmHg (- 24.71 to - 1.22, p = 0.03) was also observed. No period or carryover effects were observed. During the long-term follow-up phase the higher D-Mg2+ significantly increased ionized and total serum Mg (respectively from 0.54 to 0.64 and from 0.84 to 1.07 mmol/L; mean percentage change from baseline to follow-up + 21% and + 27%; p ≤ 0.001), while parathormone (PTH) decreased significantly (from 36.6 to 34.4 pmol/L; % change - 11%, p = 0.03). CONCLUSIONS: Increasing dialysate magnesium improves vascular stiffness in subjects undergoing maintenance hemodialysis. The present findings merit a larger trial to evaluate the effects of 0.75 mmol/L D-Mg2+ on major clinical outcomes. TRIAL REGISTRATION: The study was retrospectively registered on the ISRCTN registry (ISRCTN 74139255) on 18 June 2020.

Comparative analysis of the long-term effect of two families of high-flux polysulfone dialysers on platelet count: a retrospective cross-sectional study.

INTRODUCTION: Thrombocytopenia is a potential complication of hemodialysis (HD), and its occurrence has been described even with highly biocompatible polysulfone (PSf) membranes. Dialysis units routinely monitor platelet (PLT) count at the beginning of HD sessions. However, considering that the long-term effects on PLT count could easily be missed, the prevalence of HD-related thrombocytopenia could be underestimated. In the present study, we aimed to investigate the following: 1) the long-term impact of HD treatment on PLT count, comparing two families of dialysis membranes made up of similar PSfs; 2) whether the switch between the dialysis membranes studied significantly affects PLT count; and 3) the prevalence and the risk of HD-induced thrombocytopenia according to the dialysis membranes used. METHODS: A cross-sectional retrospective study was performed comprising 157 adult chronic HD patients. The HD membranes under investigation were of the series FX, Helixone® Fresenius (Filters A), and Polyflux® Gambro (Filters B). Patients were treated in 4 dialysis units in Southern Switzerland. Data were collected from a centralized computing platform. FINDINGS: PLT count significantly differs between Filters A and B with, respectively, 188 (153-243) ×10E9/L versus 214 (179-255) ×10E9/L (p=0.036). The prevalence of thrombocytopenia was higher for Filter A compared with Filter B (28.4% versus 12.8%; p<0.001). The switch from Filter A to Filter B significantly affected PLT count: from 189 (146-217) ×10E9/L to 217 (163-253) ×10E9/L (p<0.001; analysis on 26 patients). A linear random-intercept model confirmed the results (ß coefficient =35.214; SE =5.956; p<0.001). In a mixed-effects logistic regression model, the risk of thrombocytopenia for Filter B was 0.157 (CI =0.056-0.442). DISCUSSION: Our data suggest that among the PSf membranes studied, the FX membrane induced a lasting decrease in PLT count and caused significantly more thrombocytopenia. Prospective studies are warranted to verify our findings.

A prospective observational study comparing a non-operator dependent automatic PWV analyser to pulse pressure, in assessing arterial stiffness in hemodialysis.

BACKGROUND: Chronic kidney disease (CKD) accelerates vascular stiffening related to age. Arterial stiffness may be evaluated measuring the carotid-femoral pulse wave velocity (PWV) or more simply, as recommended by KDOQI, monitoring pulse pressure (PP). Both correlate to survival and incidence of cardiovascular disease. PWV can also be estimated on the brachial artery using a Mobil-O-Graph; a non-operator dependent automatic device. The aim was to analyse whether, in a dialysis population, PWV obtained by Mobil-O-Graph (MogPWV) is more sensitive for vascular aging than PP. METHODS: A cohort of 143 patients from 4 dialysis units has been followed measuring MogPWV and PP every 3 to 6 months and compared to a control group with the same risk factors but an eGFR > 30 ml/min. RESULTS: MogPWV contrarily to PP did discriminate the dialysis population from the control group. The mean difference translated in age between the two populations was 8.4 years. The increase in MogPWV, as a function of age, was more rapid in the dialysis group. 13.3% of the dialysis patients but only 3.0% of the control group were outliers for MogPWV. The mortality rate (16 out of 143) was similar in outliers and inliers (7.4 and 8.0%/year). Stratifying patients according to MogPWV, a significant difference in survival was seen. A high parathormone (PTH) and to be dialysed for a hypertensive nephropathy were associated to a higher baseline MogPWV. CONCLUSIONS: Assessing PWV on the brachial artery using a Mobil-O-Graph is a valid and simple alternative, which, in the dialysis population, is more sensitive for vascular aging than PP. As demonstrated in previous studies PWV correlates to mortality. Among specific CKD risk factors only PTH is associated with a higher baseline PWV. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02327962.

[Severe renal insufficiency secondary to renal cholesterol emboli: therapeutical options revisited]. / Insuffisance rénale severe sur maladie des emboles de cholestérol: controverses thérapeutiques revisitées.

Disseminated cholesterol crystal embolism is observed in elderly men with severe atherosclerosis. This syndrome may be triggered by arterial catheterizations, major vascular surgery, thrombolytic and/or anticoagulation treatment. Cutaneous signs, subacute renal insufficiency, a marked inflammatory syndrome and eosinophilia are common. Immunologic testing is normal except for hypocomplementaemia. The diagnosis may be confirmed by biopsy (skin, gastrointestinal or renal), and/or by a fundoscopic examination. The treatment consists in withdrawing all form of anticoagulation, proscribing vascular surgery and arterial catheterization, prescribing aspirin and statins, and controlling arterial blood pressure. Corticosteroids may be given in refractory cases. The prognosis of cholesterol crystal embolism is poor but may be improved by statins.

[Hypernatremia: a matter of water]. / Hypernatrémie: une question d'eau.

Hypernatremia is defined as a serum sodium concentration above the upper laboratory reference range, usually > 145 mmol/l. It is a common electrolyte disorder in the very young and the very old patient. Hospitalization itself is a risk factor for developing hypernatremia. Free water deficit is the main cause of this condition. It induces hyperosmolality and an intracellular dehydration. Clinical manifestations are mostly neurological but non-specific. A blood sample analysis is needed to establish the diagnosis. Hypernatremia is associated with a high mortality and morbidity. Treatment consists of correcting the underlying cause and the volume deficit. A brief review of this condition is proposed.

[Hypernatremia]. / Hypernatriämie--wie weiter?

Hypernatremia is defined as an elevated serum sodium concentration. Usually hypernatremia is caused by a relative water deficit occurring with decreased thirst sensation and/or reduced water intake. In rare cases hypernatremia may be caused by excessive sodium intake. Severe hypernatremia can be dangerous and can lead to significant morbidity and mortality. Dangerous hypernatremia can occur in the newborn. Drugs that influence thirst sensation are the main cause of hypernatremia in adults and elderly patients. Hospitalization itself might be a risk factor for developing hypernatremia. Therapy consists in eliminating the causes of hypernatremia and in the specific management of body volume and electrolytes.

[Anorexia nervosa and the kidney]. / Les conséquences rénales de l'anorexie.

Anorexia nervosa (AN) is a severe and potentially lethal disease of the young woman. It is defined as an anxious disorder not to gain weight, and an obsessive behavior regarding body weight and physical appearance. Different and variable patterns of behaviour are observed. This article focuses on the renal problems observed in anorexic patients. Anorexia is often associated with severe electrolyte disturbances, such as hypokalemia and hypophosphatemia, and alterations of water metabolism with hyponatremia and edema. Hypokalemia and chronic dehydration may contribute to the development of renal failure. Even end stage renal disease can be observed in these patients. A better understanding of the pathophysiology might improve treatment of patients suffering from AN.