Laure Patrier

HDL Proteome in Hemodialysis Patients: A Quantitative Nanoflow Liquid Chromatography-Tandem Mass Spectrometry Approach

Aside from a decrease in the high-density lipoprotein (HDL) cholesterol levels, qualitative abnormalities of HDL can contribute to an increase in cardiovascular (CV) risk in end-stage renal disease (ESRD) patients undergoing chronic hemodialysis (HD). Dysfunctional HDL leads to an alteration of reverse cholesterol transport and the antioxidant and anti-inflammatory properties of HDL. In this study, a quantitative proteomics approach, based on iTRAQ labeling and nanoflow liquid chromatography mass spectrometry analysis, was used to generate detailed data on HDL-associated proteins. The HDL composition was compared between seven chronic HD patients and a pool of seven healthy controls. To confirm the proteomics results, specific biochemical assays were then performed in triplicate in the 14 samples as well as 46 sex-matched independent chronic HD patients and healthy volunteers. Of the 122 proteins identified in the HDL fraction, 40 were differentially expressed between the healthy volunteers and the HD patients. These proteins are involved in many HDL functions, including lipid metabolism, the acute inflammatory response, complement activation, the regulation of lipoprotein oxidation, and metal cation homeostasis. Among the identified proteins, apolipoprotein C-II and apolipoprotein C-III were significantly increased in the HDL fraction of HD patients whereas serotransferrin was decreased. In this study, we identified new markers of potential relevance to the pathways linked to HDL dysfunction in HD. Proteomic analysis of the HDL fraction provides an efficient method to identify new and uncharacterized candidate biomarkers of CV risk in HD patients.

FGF-23 removal is improved by on-line high-efficiency hemodiafiltration compared to conventional high flux hemodialysis.

BACKGROUND Reducing circulating levels of fibroblast growth factor-23 (FGF-23) in patients on renal replacement therapy (RRT) could appear as an appealing approach for cardiovascular events prevention. The purpose of our study was to compare the clearance of FGF-23 between high flux hemodialysis (HD) and on-line hemodiafiltration (OL-HDF) procedures. METHODS Fifty-three patients were included in the HD group while 32 patients were included in the OL-HDF group. Serum pre- and post-dialysis FGF-23 levels were measured using a 2nd generation Human FGF-23 (C-Term) ELISA kit. RESULTS Mean FGF-23 reduction rates were significantly higher in OL-HDF (55.7 ± 25.2%) versus HD (36.2 ± 28.6%) groups (P=.0001), as were calculated FGF-23 clearances (P=.015) and Kt/V-FGF-23 (P=.001). Overall, post-treatment FGF-23 levels were significantly lower than pre-treatment values in both groups (P<.01). CONCLUSIONS OL-HDF achieves higher FGF-23 removal over high flux HD.

Hemolytic uremic syndrome: an unusual complication of interferon-β treatment in a MS patient

Interferon-b therapy is one of the most frequently used treatments in multiple sclerosis (MS), and is considered as safe. We report a patient with hemolytic uremic syndrome (HUS) related to recent prescription of interferon-b. A 38-year-old woman, without medical history, had a diagnosis of relapsing–remitting (RR) MS [1] (Fig. 1a). Subcutaneous interferon-b-1a (22 lg thrice weekly) was started THREE months later. Biological parameters including renal function were normal before interferon-b1a prescription. Seven months later, she presented asthenia, lower limb edema, and weight gain. She had no recent history of viral infection, transfusion, or additional drug intake. A few days later, she became oliguric. Physical examination showed high systolic and diastolic blood pressure (190/110 mmHg) and anasarca. Neurological examination was normal (EDSS score: 0). Biological parameters were the following: serum creatinine level 1,221 lmol/l (\90), urea level 31.8 mmol/l (\9), hemoglobin 4.6 g/dl (12–15). Initial platelet count was normal, followed by thrombocytopenia at 116,000/mm (250,000– 400,000). Occurrence of high LDH levels, immeasurable haptoglobin, and presence of 4 % of schistocytes, led to a diagnosis of hemolytic anemia. All autoimmune antibodies, including Coomb’s test, complement C3 and C4 levels, bacterial infection research, were normal or negative. The ADAMTS 13 activity was normal, without any ADAMTS 13 antibody and H or I factors deficit. Daily ultrafiltration and oral antihypertensive drugs were started, followed by plasma exchange and corticosteroid therapy (1 mg/kg/day). Renal biopsy confirmed acute thrombotic microangiopathy (TMA) (Fig. 1b). Absence of other causes and temporal relation between interferon-b and HUS led to a diagnosis of interferon-binduced HUS. Interferon-b-1a was withdrawn. The evolution was characterized by: (1) Three months of corticosteroids, hemodialysis, plasmapheresis, (2) occurrence of a typical posterior reversible encephalopathy syndrome (PRES) (Fig. 1c, d), secondary to the blood pressure imbalance, (3) definitive hemodialysis because of persistent anuria, (4) normalization of all hematological parameters. HUS is a type of thrombotic microangiopathy (TMA), as well as thrombotic thrombocytopenic purpura (TTP) [1–4]. HUS diagnosis is based on occurrence of mechanical hemolytic anemia, thrombocytopenia, and renal failure. High levels of LDH and reticulocytes, low haptoglobin levels, presence of schistocytes, and negative Coombs test, define the mechanical origin. Most cases are secondary to infection with Escherichia coli serotypes O157:H7, O111:H8, O103:H2, O123, O26, or other bacteria, such as E. Nerrant M. Charif P. Labauge (&) Department of Neurology, Montpellier University Hospital, 34295 Montpellier, France e-mail: labauge@yahoo.fr

Reduced glomerular filtration rate, inflammation and HDL cholesterol as main determinants of superoxide production in non-dialysis chronic kidney disease patients

Abstract Enhanced oxidative stress partly resulting from an over-production of superoxide anion (O2•−) represents a novel and particular risk factor in chronic kidney disease (CKD) patients. This study was therefore designed to evaluate O2•− determinants in this population. O2•− production was evaluated using chemiluminescence method in 136 CKD patients (79M/57F, median age: 69.5 [27.4–94.6]). Renal function (evaluated by the glomerular filtration rate using modification of diet in renal disease (MDRD)), inflammation, lipids, nutritional and bone mineral as well as clinical parameters were evaluated. Potential relationships between O2•− and these clinico-biological parameters were investigated to identify main determinants of such a pathological process. Enhanced O2•− production has been observed at the pre-dialysis phase: stages 4 and 5 of CKD (p = 0.0065). In multivariate analysis, low eGFR (MDRD <30 mL/min/1.73 m2; p = 0.046), high fibrinogen (≥3.7 g/L; p = 0.044) and abnormal HDL cholesterol (<1.42 mmol/L and ≥ 1.75 mmol/L; p = 0.042) were the main determinants of O2•− production in CKD patients.

Online high-efficiency haemodiafiltration achieves higher serum free light chain removal than high-flux haemodialysis in multiple myeloma patients: Preliminary Quantitative Study

BACKGROUND Fast reduction of serum free light chain (FLC) levels correlate with renal recovery in cast nephropathy. Because convection has the capacity to remove proteins of higher molecular weights, we hypothesized that haemodiafiltration (HDF) would be superior to haemodialysis (HD) for FLC clearance. METHODS We retrospectively identified all renal replacement therapy (RRT) sessions performed in multiple myeloma patients with pre- and post-treatment FLC measurements during a 2-year period. Using kinetic modelling, we calculated reduction percentages corrected for net ultrafiltration, effective clearances, net mass removal and Kt/V for both kappa (κ) and lambda (λ) serum FLC. RESULTS We analysed 27 (10 HD and 17 HDF) RRT sessions realized in a total of six subjects. HDF resulted in higher FLC removal rates when compared to HD. Moreover, high-efficiency (i.e. substitution volume > 15 L/session) HDF demonstrated median efficient FLC clearances roughly twice superior to high-flux HD for both κ (59.0 versus 33.8 mL/min, respectively; P < 0.01) and λ (40.5 versus 19.7 mL/min, respectively; P = 0.02) FLC. In post-dilution HDF treatments, corrected FLC reduction percentages positively correlated with substitution volumes. Total plasma proteins increased during RRT in the HDF group. CONCLUSIONS This preliminary quantitative study demonstrates the superiority of high-efficiency HDF over high-flux HD for serum FLC removal in multiple myeloma patients on RRT. No negative impact on total plasma proteins was noted.

Cardiovascular risk stratification in hemodialysis patients in the era of highly sensitive troponins: should we choose between hs-troponin I and hs-troponin T?

Abstract Background: New highly sensitive (hs) assays have challenged the interpretation of cardiac troponins (cTn). The present study was designed to evaluate simultaneously conventional cTnT and cTnI together with their corresponding highly sensitive determinations in stable hemodialysis (HD) patients. Ability of cTn to stratify HD patient risk was assessed. Methods: A total of 224 stable HD patients was included in this observational study. cTnT and hs-cTnT were measured using Roche cTnT/hs-cTnT assays based on a Cobas e601® analyzer. cTnI and hs-cTnI were measured using Beckman AccuTnI/hs-TnI IUO assays on Access II system. Patients were followed up prospectively during 9 years. Relationship between cTn level and mortality was assessed through Cox survival analysis. Results: The median cTnT and cTnI concentrations were 38.5 ng/L (IQR, 18.8–76) and 10 ng/L (IQR, 10–20), respectively. The median hs-cTnT and hs-cTnI concentrations were 62.5 ng/L (IQR, 38.8–96.3) and 13.9 ng/L (IQR, 8.4–23.6), respectively. The prevalence of values above the 99th percentile was significantly more marked with cTnT (85.3 and 97.8% for conventional and hs cTnT, respectively) than with cTnI (7.6 and 67.4% for conventional and hs cTnI, respectively). During the follow-up, 167 patients died, mainly from cardiac cause (n=77). The optimized cut-off values, determined by bootstrap method, predicting mortality were 38, 69, 20 and 11 ng/L for cTnT, hs-cTnT, cTnI and hs-cTnI, respectively. After full adjustment, elevated plasma concentrations of all troponin were significant predictors of mortality. Conclusions: A large proportion of patients free of acute coronary syndrome (ACS) has hs-cTn I or T higher than the 99th percentile which could be seen as a limiting factor for ACS screening. However, all generation and type of troponin assays could be reliable indicators of prognosis risk in HD patients.

On-Line Hemodialysis Monitoring: New Tools for Improving Safety, Tolerance and Efficacy

Hemodialysis adequacy is a complex concept that encompasses largely the dialysis dose appraisal based on monthly blood-based urea Kt/V measurement. Renal replacement therapies should provide an efficient way to clear adequately larger molecular weight solutes, to restore normal salt, electrolytes and fluid balance, to correct salt-dependent hypertension, to improve hemodynamic stability and to reduce bio-incompatibility of the hemodialysis system. Targeting such ambitious objective is obviously under the clinical supervision and judgment of nephrologists and care givers. Monitoring and achievement of these targets as a part of a continuous quality improvement process is necessary to attain dialysis adequacy goals. This review aims to provide an overview of available online hemodialysis technologies, their current applications in clinic, and the potential for future developments in improving care of chronic kidney disease patients. In order to facilitate understanding of readers we choose to classify online monitoring devices based on their clinical action.

Prevention and management of dialysis catheter complications in the intensive care unit.

Dialysis dependence at hospital discharge after acute kidney injury (AKI) requiring renal replacement therapy (RRT) in the intensive care unit (ICU) is found in 10–15% of survivors. In case of severe AKI in the ICU, it is necessary to reconcile two objectives: the creation of an adequate temporary angioaccess for RRT and the preservation of the patient’s vascular network in case of evolution to end-stage renal disease. A central venous catheter (CVC) is the best option for RRT in the ICU setting. Most catheter-related hazards can be prevented by following best clinical practices for insertion and handling of the CVC, and by knowing the advantages and disadvantages of the different types of catheters, the sites and techniques of insertion, the types of RRT modality for choosing the best CVC option, and the prophylactic and therapeutic measures to prevent and to manage the complications. We review here some important aspects of the CVC for the treatment of AKI in the ICU.

Physical inactivity and protein energy wasting play independent roles in muscle weakness in maintenance haemodialysis patients

Background Muscle weakness is associated with increased mortality risk in chronic haemodialysis (CHD) patients. Protein energy wasting (PEW) and low physical activity could impair muscle quality and contribute to muscle weakness beyond muscle wasting in these patients. Aim of this study was to assess clinical and biological parameters involved in the reduction of muscle strength of CHD patients. Methods One hundred and twenty-three CHD patients (80 males, 43 females; 68,8 [57.9–78.8] y.o.) were included in this study. Maximal voluntary force (MVF) of quadriceps was assessed using a belt-stabilized hand-held dynamometer. Muscle quality was evaluated by muscle specific torque, defined as the strength per unit of muscle mass. Muscle mass was estimated using lean tissue index (LTI), skeletal muscle mass (SMM) assessed by bioelectrical impedance analysis and creatinine index (CI). Voorrips questionnaire was used to estimate physical activity. Criteria for the diagnosis of PEW were serum albumin, body mass index < 23 kg/m2, creatinine index < 18.82 mg/kg/d and low dietary protein intake estimated by nPCR < 0.80g/kg/d. Results MVF was 76.1 [58.2–111.7] N.m. and was associated with CI (β = 5.3 [2.2–8.4], p = 0.001), LTI (β = 2.8 [0.6–5.1], p = 0.013), Voorrips score (β = 17.4 [2.9–31.9], p = 0.02) and serum albumin (β = 1.9 [0.5–3.2], p = 0.006). Only serum albumin (β = 0.09 [0.03–0.15], p = 0.003), Voorrips score (β = 0.8 [0.2–1.5], p = 0.005) and CI (β = 0.2 [0.1–0.3], p<0.001) remained associated with muscle specific torque. Thirty patients have dynapenia defined as impaired MVF with maintained SMM and were younger with high hs-CRP (p = 0.001), PEW criteria (p<0.001) and low Voorrips score (p = 0.001), and reduced dialysis vintage (p<0.046). Conclusions Beyond atrophy, physical inactivity and PEW conspire to impair muscle strength and specific torque in CHD patients and could be related to muscle quality. Trial registration ClinicalTrials.gov NCT02806089