Citrate anticoagulation abolishes degranulation of polymorphonuclear cells and platelets and reduces oxidative stress during haemodialysis

Can regional anticoagulation with calcium-free dialysate be extended to maintenance hemodialysis?

BACKGROUND

Regional anticoagulation in hemodialysis avoids the use of heparin, which is responsible for both hemorrhagic and non-hemorrhagic complications. Typically, blood is decalcified by injecting citrate into the arterial line of the extracorporeal circuit. Calcium-free dialysate improves anticoagulation efficacy but requires injection of a calcium-containing solution into the venous line and strict monitoring of blood calcium levels. Recent improvements have made regional anticoagulation with calcium-free dialysate safer and easier.

OBSERVATIONS

(1) Adjusting the calcium injection rate to ionic dialysance avoids the risk of dyscalcemia, thus making unnecessary the monitoring of blood calcium levels. This adjustment could be carried out automatically by the hemodialysis monitor. (2) As calcium-free dialysate reduces the amount of citrate required, this can be supplied by dialysate obtained from currently available concentrates containing citric acid. This avoids the need for citrate injection and the risk of citrate overload. (3) Calcium-free dialysate no longer needs the dialysate acidification required for avoiding calcium carbonate precipitation in bicarbonate-containing dialysate.

CONCLUSIONS

Regional anticoagulation with calcium-free dialysate enables an acid- and heparin-free procedure that is more biocompatible and environmentally friendly than conventional bicarbonate hemodialysis. The availability of specific acid-free concentrates and adapted hemodialysis monitors is required to extend this procedure to maintenance hemodialysis.

Metabolic Control During Macrophage Polarization by a Citrate-Functionalized Scaffold for Maintaining Bone Homeostasis

Metabolites, as markers of phenotype at the molecular level, can regulate the function of DNA, RNA, and proteins through chemical modifications or interactions with large molecules. Citrate is an important metabolite that affects macrophage polarization and osteoporotic bone function. Therefore, a better understanding of the precise effect of citrate on macrophage polarization may provide an effective alternative strategy to reverse osteoporotic bone metabolism. In this study, a citrate functional scaffold to control the metabolic pathway during macrophage polarization based on the metabolic differences between pro-inflammatory and anti-inflammatory phenotypes for maintaining bone homeostasis, is fabricated. Mechanistically, only outside M1 macrophages are accumulated high concentrations of citrate, in contrast, M2 macrophages consume massive citrate. Therefore, citrate-functionalized scaffolds exert more sensitive inhibitory effects on metabolic enzyme activity during M1 macrophage polarization than M2 macrophage polarization. Citrate can block glycolysis-related enzymes by occupying the binding-site and ensure sufficient metabolic flux in the TCA cycle, so as to turn the metabolism of macrophages to oxidative phosphorylation of M2 macrophage, largely maintaining bone homeostasis. These studies indicate that exogenous citrate can realize metabolic control of macrophage polarization for maintaining bone homeostasis in osteoporosis.

Anticoagulation for people receiving long-term haemodialysis

BACKGROUND

Haemodialysis (HD) requires safe and effective anticoagulation to prevent clot formation within the extracorporeal circuit during dialysis treatments to enable adequate dialysis and minimise adverse events, including major bleeding. Low molecular weight heparin (LMWH) may provide a more predictable dose, reliable anticoagulant effects and be simpler to administer than unfractionated heparin (UFH) for HD anticoagulation, but may accumulate in the kidneys and lead to bleeding.

OBJECTIVES

To assess the efficacy and safety of anticoagulation strategies (including both heparin and non-heparin drugs) for long-term HD in people with kidney failure. Any intervention preventing clotting within the extracorporeal circuit without establishing anticoagulation within the patient, such as regional citrate, citrate enriched dialysate, heparin-coated dialysers, pre-dilution haemodiafiltration (HDF), and saline flushes were also included.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to November 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised controlled studies (quasi-RCTs) evaluating anticoagulant agents administered during HD treatment in adults and children with kidney failure.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias using the Cochrane tool and extracted data. Treatment effects were estimated using random effects meta-analysis and expressed as relative risk (RR) or mean difference (MD) with 95% confidence intervals (CI). Evidence certainty was assessed using the Grading of Recommendation, Assessment, Development and Evaluation approach (GRADE).

MAIN RESULTS

We included 113 studies randomising 4535 participants. The risk of bias in each study was adjudicated as high or unclear for most risk domains. Compared to UFH, LMWH had uncertain effects on extracorporeal circuit thrombosis (3 studies, 91 participants: RR 1.58, 95% CI 0.46 to 5.42; I2 = 8%; low certainty evidence), while major bleeding and minor bleeding were not adequately reported. Regional citrate anticoagulation may lower the risk of minor bleeding compared to UFH (2 studies, 82 participants: RR 0.34, 95% CI 0.14 to 0.85; I2 = 0%; low certainty evidence). No studies reported data comparing regional citrate to UFH on risks of extracorporeal circuit thrombosis and major bleeding. The effects of very LMWH, danaparoid, prostacyclin, direct thrombin inhibitors, factor XI inhibitors or heparin-grafted membranes were uncertain due to insufficient data. The effects of different LMWH, different doses of LMWH, and the administration of LMWH anticoagulants using inlet versus outlet bloodline or bolus versus infusion were uncertain. Evidence to compare citrate to another citrate or control was scant. The effects of UFH compared to no anticoagulant therapy or different doses of UFH were uncertain. Death, dialysis vascular access outcomes, blood transfusions, measures of anticoagulation effect, and costs of interventions were rarely reported. No studies evaluated the effects of treatment on non-fatal myocardial infarction, non-fatal stroke and hospital admissions. Adverse events were inconsistently and rarely reported.

AUTHORS' CONCLUSIONS

Anticoagulant strategies, including UFH and LMWH, have uncertain comparative risks on extracorporeal circuit thrombosis, while major bleeding and minor bleeding were not adequately reported. Regional citrate may decrease minor bleeding, but the effects on major bleeding and extracorporeal circuit thrombosis were not reported. Evidence supporting clinical decision-making for different forms of anticoagulant strategies for HD is of low and very low certainty, as available studies have not been designed to measure treatment effects on important clinical outcomes.

Regional Citrate Anticoagulation: A Tale of More Than Two Stories

Calcium is a key clotting factor, and several inorganic molecules that bind to calcium have been found to reduce the clotting propensity of blood. Citrate, a calcium chelator, is used as inhibitor of the coagulation cascade in blood transfusion. Also, it is used as an anaticoagulant during dialysis to maintain patency of the extracorporeal circuit, known as regional citrate anticoagulation (RCA). The amount of citrate should be chosen such that ionized calcium concentrations in the extracorporeal circuit are reduced enough to minimize propagation of the coagulation cascade. The dialytic removal of the calcium-citrate complexes combined with reduced ionized calcium concentrations makes necessary calcium supplementation of the blood returning to the patient. This can be achieved in different ways. In classical RCA, citrate and calcium are infused in the afferent and efferent tubing, respectively, whereas the dialysate does not contain calcium. This setup has been shown to be highly efficacious with a very low clotting propensity. Strict monitoring of blood electrolytes is required. Alternatively, the use of a high-calcium dialysate leads to calcium loading, obviating the need for a separate calcium infusion pump. The main advantages are simplified delivery of RCA and less fluctuation of systemic calcium concentrations. Currently, citric acid is sometimes added to the acid concentrate as a replacement for acetic acid. Differences and similarities between RCA and citrate-containing dialysate are discussed. RCA is an excellent alternative to heparin for patients at high risk of bleeding.

Archetypal sustained low-efficiency daily diafiltration (SLEDD-f) for critically ill patients requiring kidney replacement therapy: towards an adequate therapy

Sustained low-efficiency dialysis is a hybrid form of kidney replacement therapy that has gained increasing popularity as an alternative to continuous forms of kidney replacement therapy in intensive care unit settings. During the COVID-19 pandemic, the shortage of continuous kidney replacement therapy equipment led to increasing usage of sustained low-efficiency dialysis as an alternative treatment for acute kidney injury. Sustained low-efficiency dialysis is an efficient method for treating hemodynamically unstable patients and is quite widely available, making it especially useful in resource-limited settings. In this review, we aim to discuss the various attributes of sustained low-efficiency dialysis and how it is comparable to continuous kidney replacement therapy in efficacy, in terms of solute kinetics and urea clearance, and the various formulae used to compare intermittent and continuous forms of kidney replacement therapy, along with hemodynamic stability. During the COVID-19 pandemic, there was increased clotting of continuous kidney replacement therapy circuits, which led to increased use of sustained low-efficiency dialysis alone or together with extra corporeal membrane oxygenation circuits. Although sustained low-efficiency dialysis can be delivered with continuous kidney replacement therapy machines, most centers use standard hemodialysis machines or batch dialysis systems. Even though antibiotic dosing differs between continuous kidney replacement therapy and sustained low-efficiency dialysis, reports of patient survival and renal recovery are similar for continuous kidney replacement therapy and sustained low-efficiency dialysis. Health care studies indicate that sustained low-efficiency dialysis has emerged as a cost-effective alternative to continuous kidney replacement therapy. Although there is considerable data to support sustained low-efficiency dialysis treatments for critically ill adult patients with acute kidney injury, there are fewer pediatric data, even so, currently available studies support the use of sustained low-efficiency dialysis for pediatric patients, particularly in resource-limited settings.

Management of regional citrate anticoagulation for continuous renal replacement therapy: guideline recommendations from Chinese emergency medical doctor consensus

Continuous renal replacement therapy (CRRT) is widely used for treating critically-ill patients in the emergency department in China. Anticoagulant therapy is needed to prevent clotting in the extracorporeal circulation during CRRT. Regional citrate anticoagulation (RCA) has been shown to potentially be safer and more effective and is now recommended as the preferred anticoagulant method for CRRT. However, there is still a lack of unified standards for RCA management in the world, and there are many problems in using this method in clinical practice. The Emergency Medical Doctor Branch of the Chinese Medical Doctor Association (CMDA) organized a panel of domestic emergency medicine experts and international experts of CRRT to discuss RCA-related issues, including the advantages and disadvantages of RCA in CRRT anticoagulation, the principle of RCA, parameter settings for RCA, monitoring of RCA (mainly metabolic acid-base disorders), and special issues during RCA. Based on the latest available research evidence as well as the paneled experts' clinical experience, considering the generalizability, suitability, and potential resource utilization, while also balancing clinical advantages and disadvantages, a total of 16 guideline recommendations were formed from the experts' consensus.

The effects of differing anticoagulant regimes on blood quality after cell salvage in coronary artery bypass grafting (CABG): a pilot study

BACKGROUND

Cell salvage reduces allogenic blood transfusion requirements in surgery. We present a pilot study exploring the impact of anticoagulant choice, citrate or heparin, on the quality of cell salvaged blood in adults undergoing coronary artery bypass grafting (CABG).

MATERIALS AND METHODS

Elective on pump CABG patients were randomly allocated to citrate or heparin anticoagulation. We measured red blood cell characteristics and inflammation in both the blood collection reservoir and the washed red blood cell concentrate. Postoperatively, the level of biomarkers and the coagulation profile in the peripheral blood as well as the transfusion requirements of allogenic blood products were studied.

RESULTS

Thirty eight patients were included, 19 in the citrate group and 19 in the heparin group. Baseline characteristics were similar. In the washed red blood cell concentrate, Mean Hb (g/dl) and Ht (%) were lower in the citrate group [Hb: 18.1 g/dL (SD 1.3) vs. 21.1 (1.6), p < 0.001; Ht: 59.9% (54.7-60.9) vs. 63.7% (62.3-64.8); p < 0.001]; Mean corpuscular volume (MCV, μm 3) was higher [99.1fL (9.4) vs. 88 (4.2), p < 0.001] and mean corpuscular hemoglobin concentration (MCHC, g/dl) lower in the citrate group [31.9 g/dl (29.6-32.4) vs. 33.6 (33.1-34.0) p < 0.001]. Thrombocyte count (1000/μl) was higher in the citrate group [31.0 (26.0-77.0) vs. 13.0 (10.0-39.0); p = 0.006]. There were no differences in the requirement for allogenic blood products' transfusion (intraoperatively and postoperatively) or in the coagulation parameters after washed red blood cell concentrate infusion. Higher IL-10 was found in the citrate group in the blood collection reservoir, higher neutrophil-derived myeloperoxidase (MPO) in the heparin group after washed red blood cell concentrate infusion.

CONCLUSION

Though red blood cells in washed red blood cell concentrate were more swollen and diluted in the citrate group with more residual thrombocytes, published quality guidelines were met in both groups. Our pilot study suggests that differences in inflammatory markers in the blood collection reservoir and after infusion of washed red blood cell concentrate indicate a possible pro-inflammatory effect of heparin compared to citrate. A larger study is warranted to confirm these results and their possible clinical consequences. Trial registration ClinicalTrials.gov : NCT02674906. Registered 5 February 2016.

Integrating network pharmacology and transcriptomic validation to investigate the efficacy and mechanism of Mufangji decoction preventing lung cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Mufangji decoction (MFJD), a famous traditional Chinese medicine formula in Synopsis of Golden Chamber (Jingui yaolue), has been utilized to treat cough and asthma and release chest pain over 2000 years in China. Chinese old herbalist doctor use MFJD to treat lung cancer and cancerous pleural fluid, but the preventive effect of MFJD on lung cancer and the underlying mechanism are indefinite.

AIM OF THE STUDY

The goal of this study is to explore the efficacy and mechanism of Mufangji decoction preventing lung cancer referring to the traditional use.

MATERIALS AND METHODS

Tumor allograft experiment and host versus tumor experiment were used to observe the direct anti-tumor effect and indirect anti-tumor immune effect, the mouse lung carcinogenic model was used to evaluate the dose-response and the preventive effect of MFJD on lung cancer. The active ingredients of MFJD were obtained by UPLC-MS/MS. The potential targets of MFJD were screened by network pharmacology and transcriptomics. The therapeutic targets and pathways of MFJD on lung cancer were obtained by protein-protein interaction, molecular docking and David database. The predicted results were verified in vitro and in vivo.

RESULTS

MFJD could significantly prevent tumor growth in host versus tumor experiment but could not in tumor allograft experiment, indicating an anti-tumor immune effect against lung cancer. MFJD could reduce lung nodules with a dose-response in mouse lung carcinogenic model. Myeloperoxidase (MPO) was selected as the core target due to the highest degree value in Protein-Protein interaction network and had potently binding activity to sinomenine and dehydrocostus lactone in molecular docking. In vivo, MPO-expressed neutrophils are negatively correlated with lung cancer progression and MFJD could promote the neutrophil-related immune surveillance. In vitro, sinomenine and dehydrocostus lactone could promote neutrophil phagocytosis, MPO and ROS production in a dose dependent manner. The major compounds from MFJD were identified to regulate 36 targets for lung cancer prevention by UPLC-MS/MS, network pharmacology and transcriptomics. David database exhibited that MFJD plays an important role in immunoregulation by modulating 4 immune-related biological processes and 3 immune-related pathways.

CONCLUSIONS

MFJD prevents lung cancer by mainly promoting MPO expression to maintain neutrophil immune surveillance, its key compounds are sinomenine and dehydrocostus lactone.

Use of regional citrate anticoagulation with medium cut-off membrane: pilot report

Background

Regional citrate anticoagulation during hemodialysis provides an immediate and complete anticoagulant effect, which is limited to the extracorporeal circuit. Citrate has become the standard anticoagulant in acute renal replacement therapy and is widely used in various intermittent hemodialysis modalities, especially for patients with contraindications for heparin. With the increased adoption of medium cut-off membranes, experience with regional citrate anticoagulation is needed. To our knowledge, this is the first report to assess the feasibility of regional citrate anticoagulation in expanded hemodialysis.

Methods

We prospectively analyzed 5 expanded hemodialysis procedures in 5 patients in which a medium cut-off membrane (Theranova®) was used. We followed our standard citrate protocol developed and tested for high-flux membrane. Anticoagulation was performed with a continuous infusion of 8% trisodium citrate into the arterial line and supplementation of 1 M calcium chloride into the venous line. We monitored ionized calcium and magnesium, sodium and blood gas analysis. Anticoagulation effectiveness was assessed by post-filter ionized calcium and by visual inspection of the anticoagulation in the circuit.

Results

There were no prematurely terminated procedures due to anticoagulation-related complications. With a blood flow of 250 mL/min and a dialysate flow of 500 mL/min, we were able to maintain serum ionized calcium in the range of 0.89–1.29 mmol/L and serum sodium in the range of 136–144 mmol/L. The mean pre- and post-dialysis arterial circuit pH was 7.42 (± 0.04) and 7.53 (± 0.23), respectively. The mean pre- and post-dialysis serum ionized magnesium was 0.54 (± 0.04) mmol/L and 0.43 (± 0.03) mmol/L, respectively (measurements were done on a point-of-care ionometer with a lower normal range for ionized magnesium).

Conclusion

We have shown that our standard citrate protocol for high-flux hemodialysis membrane could be successfully adopted for use in expanded hemodialysis with a medium cut-off membrane. Overall, electrolyte and acid-base balances were relatively well-controlled and anticoagulation effectiveness was excellent.

Trial registration

This is a pilot report with results taken from a larger ongoing trial (registered at ClinicalTrials.gov on October 25, 2019 under number NCT04139525) comparing citrate and heparin anticoagulation during expanded hemodialysis.

Heparin-free regional anticoagulation of haemodialysis filters with calcium-free dialysate: is citrate mandatory?

Background

There is an unmet need to develop safe and successful heparin-free regional anticoagulation modalities in haemodialysed patients at risk of bleeding. Whether the addition of citrate as a prefilter injection or in the dialysate itself is required to reach anticoagulation objectives when calcium-free dialysate is used as regional anticoagulation remains unclear.

Methods

In this monocentric retrospective study, we report our experience of 908 dialysis sessions performed with a calcium-free citrate-containing dialysate and calcium reinjection according to the ionic dialysance, without additional heparin.

Results

Premature termination for filter clotting occurred in 20 sessions (2.2%) and duration of session was >4.5 h in 135 (15%; maximum duration 6 h). In addition, we could investigate the citrate, calcium and acid–basis status during haemodialysis sessions performed with (citrate group, n = 20 sessions) or without (citrate-free group, n = 19 sessions) citrate in the dialysate. In 20 sessions performed in patients with underlying liver disorders and using calcium-free citrate-containing dialysate, patients’ ionized calcium (iCa) and serum citrate levels were stable and remained within the normal range, respectively. Post-filter iCa was below 0.4 mmol/L in 19/20 sessions and citrate was 0.304 mmol/L (range: 0.011; 0.548). In 19 sessions that used calcium and citrate-free dialysate, post-filter iCa was 0.41 mmol/L (0.34; 0.5) and all sessions extended to 4 h or beyond.

Conclusions

Regional anticoagulation of haemodialysis with a calcium-free dialysate and calcium reinjection according to the ionic dialysance is safe. Adding citrate to the dialysate is not mandatory to prevent dialysis circuit clotting in most patients.

Early warning of citric acid overdose and timely adjustment of regional citrate anticoagulation based on machine learning methods

Background

Regional citrate anticoagulation (RCA) is an important local anticoagulation method during bedside continuous renal replacement therapy. To improve patient safety and achieve computer assisted dose monitoring and control, we took intensive care units patients into cohort and aiming at developing a data-driven machine learning model to give early warning of citric acid overdose and provide adjustment suggestions on citrate pumping rate and 10% calcium gluconate input rate for RCA treatment.

Methods

Patient age, gender, pumped citric acid dose value, 5% NaHCO₃ solvent, replacement fluid solvent, body temperature value, and replacement fluid PH value as clinical features, models attempted to classify patients who received regional citrate anticoagulation into correct outcome category. Four models, Adaboost, XGBoost, support vector machine (SVM) and shallow neural network, were compared on the performance of predicting outcomes. Prediction results were evaluated using accuracy, precision, recall and F1-score.

Results

For classifying patients at the early stages of citric acid treatment, the accuracy of neutral networks model is higher than Adaboost, XGBoost and SVM, the F1-score of shallow neutral networks (90.77%) is overall outperformed than other models (88.40%, 82.17% and 88.96% for Adaboost, XGBoost and SVM). Extended experiment and validation were further conducted using the MIMIC-III database, the F1-scores for shallow neutral networks, Adaboost, XGBoost and SVM are 80.00%, 80.46%, 80.37% and 78.90%, the AUCs are 0.8638, 0.8086, 0.8466 and 0.7919 respectively.

Conclusion

The results of this study demonstrated the feasibility and performance of machine learning methods for monitoring and adjusting local regional citrate anticoagulation, and further provide decision-making recommendations to clinicians point-of-care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-021-01489-8.

Biocompatibility Parameters with Standard and Increased Dose of Citrate in Hemodialysis-A Randomized Trial

Background: The dose of citrate needed in regional citrate anticoagulation (RCA) to achieve optimal biocompatibility is unknown. We performed a randomized trial comparing two doses (ACTRN12613001340729). Methods: In 30 patients a single hemodialysis with either standard (2.7 mmol/L) or increased dose of citrate (4 mmol/L) was performed. C5a-desArg, myeloperoxidase (MPO), thrombin-antithrombin complex (TAT), and platelet factor 4 (PF4) were measured and the inner surface of the dialyzer fibers was evaluated with scanning electron microscopy (SEM). Results: A good separation of anticoagulation effect was achieved (post-filter ionized calcium 0.20 vs. 0.31 mmol/L, p < 0.05). There was no effect of citrate dose on any of the biocompatibility parameters; transient and parallel increase in PF4 after 30 min and parallel increase in TAT after 4 h were observed. There were no visually detected clotting problems within the circuit and no significant hypocalcemia in either group. SEM clotting score was excellent and comparable in both groups (p = 0.59). Conclusions: Given the excellent results in both groups, absence of between group differences and inability of the increased dose of citrate to completely blunt the small residual increase in PF4 and TAT, we conclude that the standard dose of citrate seems sufficient in RCA for chronic hemodialysis.

Could Antioxidant Supplementation Delay Progression of Cardiovascular Disease in End-Stage Renal Disease Patients?

In end-stage renal disease patients, the leading causes of mortality are of cardiovascular (CV) origin. The underlying mechanisms are complex, given that sudden heart failure is more common than acute myocardial infarction. A contributing role of oxidative stress is postulated, which is increased even at early stages of chronic kidney disease, is gradually augmented in parallel to progression to endstage renal disease and is further accelerated by renal replacement therapy. Oxidative stress ensues when there is an imbalance between reactive pro-oxidants and physiologically occurring electron donating antioxidant defence systems. During the last decade, a close association of oxidative stress with accelerated atherosclerosis and increased risk for CV and all-cause mortality has been established. Lipid peroxidation has been identified as a trigger for endothelial dysfunction, the first step towards atherogenesis. In order to counteract the deleterious effects of free radicals and thereby ameliorate, or delay, CV disease, exogenous administration of antioxidants has been proposed. Here, we attempt to summarize existing data from studies that test antioxidants for CV protection, such as vitamins E and C, statins, omega-3 fatty acids and N-acetylcysteine.

Citrate high volume on-line hemodiafiltration modulates serum Interleukin-6 and Klotho levels: the multicenter randomized controlled study "Hephaestus"

BACKGROUND

Studies addressing the anti-inflammatory properties of citrate dialysate enrolled patients in both hemodialysis (HD) and hemodiafiltration (HDF), the latter not adjusted for adequate convective exchange. This is a potential source of confounding in that HDF itself has anti-inflammatory effects regardless of the buffer, and optimal clinical outcomes are related to the amount of convection.

METHODS

To distinguish the merits of the buffer from those of convection, we performed a 6-month, prospective, randomized, crossover AB-BA study. Comparisons were made during the 3-month study period of on-line HDF with standard dialysate containing three mmol of acetic acid (OL-HDFst) and the 3-month of OL-HDF with dialysate containing one mmol of citric acid (OL-HDFcit). Primary outcome measure of the study was interleukin-6 (IL-6). Klotho, high sensitivity C-reactive protein (hsCRP), fetuin and routine biochemical parameters were also analyzed.

RESULTS

We analyzed 47 patients (mean age 64 years, range 27-84 years) enrolled in 10 participating Nephrology Units. Convective volumes were around 25 L/session with 90 percent of sessions > 20 L and ß2-microglobulin reduction rate 76% in both HDFs. Baseline median IL-6 values in OL-HDFst were 5.6 pg/ml (25:75 interquartile range IQR 2.9:10.6) and in OL-HDFcit 6.6 pg/ml (IQR 3.4:11.4 pg/ml). The difference was not statistically significant (p 0.88). IL-6 values were lower during OL-HDFcit than during OL-HDFst, both when analyzed as the median difference of overall IL-6 values (p 0.02) and as the median of pairwise differences between the baseline and the 3-month time points (p 0.03). The overall hsCRP values too, were lower during OL-HDFcit than during OL-HDFst (p 0.01). Klotho levels showed a time effect (p 0.02) and the increase was significant only during OL-HDFcit (p 0.01).

CONCLUSIONS

Citrate buffer modulated IL-6, hsCRP and Klotho levels during high volume OL-HDF. These results are not attributable to differences in the dialysis technology that was applied and may suggest a potential biological effect of citrate on CKD-associated inflammatory state. ClinicalTrials.gov identifier NCT02863016.

Comparison between regional citrate anticoagulation and heparin for intermittent hemodialysis in ICU patients: a propensity score-matched cohort study

BACKGROUND

Regional citrate anticoagulation (RCA) is the gold standard of anticoagulation for continuous renal replacement therapy but is rarely used for intermittent hemodialysis (IHD) in ICU. Few studies assessed the safety and efficacy of RCA during IHD in ICU; however, no data are available comparing RCA to heparin anticoagulation, which are commonly used for IHD. The aim of this study was to assess the efficacy and safety of RCA compared to heparin anticoagulation during IHD.

METHODS

This retrospective single-center cohort study included consecutive ICU patients treated with either heparin anticoagulation (unfractionated or low-molecular-weight heparin) or RCA for IHD from July to September in 2015 and 2017. RCA was performed with citrate infusion according to blood flow and calcium infusion by diffusive influx from dialysate. Using a propensity score analysis, as the primary endpoint we assessed whether RCA improved efficacy, quantified with Kt/V from the ionic dialysance, compared to heparin anticoagulation. The secondary endpoint was safety. Exploratory analyses were performed on the changes in efficacy and safety between the implementation period (2015) and at long term (2017).

RESULTS

In total, 208 IHD sessions were performed in 56 patients and were compared (124 RCA and 84 heparin coagulation). There was no difference in Kt/V between RCA and heparin (0.95 ± 0.38 vs. 0.89 ± 0.32; p = 0.98). A higher number of circuit clotting (12.9% vs. 2.4%; p = 0.02) and premature interruption resulting from acute high transmembrane pressure (21% vs. 7%; p = 0.02) occurred in the RCA sessions compared to the heparin sessions. In the propensity score-matching analysis, RCA was associated with an increased risk of circuit clotting (absolute differences = 0.10, 95% CI [0.03-0.18]; p = 0.008). There was no difference in efficacy and safety between the two time periods (2015 and 2017).

CONCLUSION

RCA with calcium infusion by diffusive influx from dialysate for IHD was easy to implement with stable long-term efficacy and safety but did not improve efficacy and could be associated with an increased risk of circuit clotting compared to heparin anticoagulation in non-selected ICU patients. Randomized trials to determine the best anticoagulation for IHD in ICU patients should be conducted in a variety of settings.

Large-Scale Multi-omic Analysis of COVID-19 Severity

We performed RNA-seq and high-resolution mass spectrometry on 128 blood samples from COVID-19-positive and COVID-19-negative patients with diverse disease severities and outcomes. Quantified transcripts, proteins, metabolites, and lipids were associated with clinical outcomes in a curated relational database, uniquely enabling systems analysis and cross-ome correlations to molecules and patient prognoses. We mapped 219 molecular features with high significance to COVID-19 status and severity, many of which were involved in complement activation, dysregulated lipid transport, and neutrophil activation. We identified sets of covarying molecules, e.g., protein gelsolin and metabolite citrate or plasmalogens and apolipoproteins, offering pathophysiological insights and therapeutic suggestions. The observed dysregulation of platelet function, blood coagulation, acute phase response, and endotheliopathy further illuminated the unique COVID-19 phenotype. We present a web-based tool (covid-omics.app) enabling interactive exploration of our compendium and illustrate its utility through a machine learning approach for prediction of COVID-19 severity.

Continuous Renal Replacement Therapy in Venovenous Extracorporeal Membrane Oxygenation: A Retrospective Study on Regional Citrate Anticoagulation

Systemic infusion of unfractionated heparin (UFH) is the standard anticoagulation technique for continuous renal replacement therapy (CRRT) during extracorporeal membrane oxygenation (ECMO), but often fails to avoid CRRT circuit clotting. The aim of this study was to assess, in patients undergoing CRRT during venovenous ECMO (vv-ECMO), the efficacy and safety of adding regional citrate anticoagulation (RCA) for CRRT circuit anticoagulation (RCA + UFH group) compared with the sole systemic heparin anticoagulation (UFH group). We performed a retrospective chart review (2009-2018) of patients treated with CRRT during ECMO. We evaluated filter life span, rate of CRRT circuit clotting, and coagulation parameters. The incidence of citrate anticoagulation-related complications was recorded. Forty-eight consecutive adult patients underwent CRRT during vv-ECMO in the study period. The incidence of CRRT circuit clotting was lower in the RCA + UFH group (11% vs. 38% in the UFH group, p < 0.001). Log-rank survival analysis demonstrated longer circuit lifetime for RCA + UFH group. No complication ascribable to citrate anticoagulation was recorded. Regional citrate anticoagulation resulted a feasible, safe, and effective technique as additional anticoagulation for CRRT circuits during ECMO. Compared with systemic heparinization only, this technique allowed to reduce the rate of CRRT circuit clotting.

Effect of Regional Citrate Anticoagulation vs Systemic Heparin Anticoagulation During Continuous Kidney Replacement Therapy on Dialysis Filter Life Span and Mortality Among Critically Ill Patients With Acute Kidney Injury: A Randomized Clinical Trial

IMPORTANCE

Although current guidelines suggest the use of regional citrate anticoagulation (which involves the addition of a citrate solution to the blood before the filter of the extracorporeal dialysis circuit) as first-line treatment for continuous kidney replacement therapy in critically ill patients, the evidence for this recommendation is based on few clinical trials and meta-analyses.

OBJECTIVE

To determine the effect of regional citrate anticoagulation, compared with systemic heparin anticoagulation, on filter life span and mortality.

DESIGN, SETTING, AND PARTICIPANTS

A parallel-group, randomized multicenter clinical trial in 26 centers across Germany was conducted between March 2016 and December 2018 (final date of follow-up, January 21, 2020). The trial was terminated early after 596 critically ill patients with severe acute kidney injury or clinical indications for initiation of kidney replacement therapy had been enrolled.

INTERVENTIONS

Patients were randomized to receive either regional citrate anticoagulation (n = 300), which consisted of a target ionized calcium level of 1.0 to 1.40 mg/dL, or systemic heparin anticoagulation (n = 296), which consisted of a target activated partial thromboplastin time of 45 to 60 seconds, for continuous kidney replacement therapy.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes were filter life span and 90-day mortality. Secondary end points included bleeding complications and new infections.

RESULTS

Among 638 patients randomized, 596 (93.4%) (mean age, 67.5 years; 183 [30.7%] women) completed the trial. In the regional citrate group vs systemic heparin group, median filter life span was 47 hours (interquartile range [IQR], 19-70 hours) vs 26 hours (IQR, 12-51 hours) (difference, 15 hours [95% CI, 11 to 20 hours]; P < .001). Ninety-day all-cause mortality occurred in 150 of 300 patients vs 156 of 296 patients (Kaplan-Meier estimator percentages, 51.2% vs 53.6%; unadjusted difference, -2.4% [95% CI, -10.5% to 5.8%]; unadjusted hazard ratio, 0.91 [95% CI, 0.72 to 1.13]; unadjusted P = .38; adjusted difference, -6.1% [95% CI, -12.6% to 0.4%]; primary adjusted hazard ratio, 0.79 [95% CI, 0.63 to 1.004]; primary adjusted P = .054). Of 38 prespecified secondary end points, 34 showed no significant difference. Compared with the systemic heparin group, the regional citrate group had significantly fewer bleeding complications (15/300 [5.1%] vs 49/296 [16.9%]; difference, -11.8% [95% CI, -16.8% to -6.8%]; P < .001) and significantly more new infections (204/300 [68.0%] vs 164/296 [55.4%]; difference, 12.6% [95% CI, 4.9% to 20.3%]; P = .002).

CONCLUSIONS AND RELEVANCE

Among critically ill patients with acute kidney injury receiving continuous kidney replacement therapy, anticoagulation with regional citrate, compared with systemic heparin anticoagulation, resulted in significantly longer filter life span. The trial was terminated early and was therefore underpowered to reach conclusions about the effect of anticoagulation strategy on mortality.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02669589.

Effect of uremic serum on Th17/Treg cell balance and endoplasmic reticulum stress in rats

BACKGROUND/AIMS

The imbalance of T helper 17 (Th17) and regulatory T (Treg) cells exists in the occurrence and development of various diseases. Endoplasmic reticulum stress (ERS) is an important self-protective cellular response to harmful stimuli, such as uremic environment. The objective of this study was to investigate the Th17/Treg cell balance and ERS in a uremic environment and analyze the relationship between them.

METHODS

(1) The rat spleen lymphocytes were extracted and treated with thapsigargin (inducer of ERS) and sodium citrate. The proportion of Th17 and Treg cells were then detected. (2) The uremic serum-cultured lymphocytes were used and divided into three groups: non-uremic serum group, uremic serum group, and uremic serum + sodium citrate group. Afterward, the proportion of Th17/Treg cells and the expression of ERS-related proteins (GRP78 and CHOP) were detected.

RESULTS

Thapsigargin had no significant effect on the proportion of Th17 cells within a limited concentration range, but it could reduce the proportion of Treg cells, sodium citrate had a negative influence on the deviation of Th17/Treg cells treated with thapsigargin. Uremic serum treatment reduced the proportion of Treg cells, resulting in an increase of the Th17/Treg ratio. However, sodium citrate had no influence on the deviation of Th17/Treg cells treated by uremic serum. Sodium citrate reduced the elevation of ERS-related proteins induced by uremic serum.

CONCLUSIONS

Uremic serum can lead to the imbalance of Th17/Treg cells as well as ERS, suggesting that ERS is one of the mechanisms of the imbalance of Th17/Treg cells induced by uremic serum. Sodium citrate can inhibit ERS induced by uremic serum.

Impact of anion exchange adsorbents on regional citrate anticoagulation

INTRODUCTION

Heparin and citrate are commonly used anticoagulants in membrane/adsorption based extracorporeal liver support systems. However, anion exchange resins employed for the removal of negatively charged target molecules including bilirubin may also deplete these anticoagulants due to their negative charge. The aim of this study was to evaluate the adsorption of citrate by anion exchange resins and the impact on extracorporeal Ca²⁺ concentrations.

METHODS

Liver support treatments were simulated in vitro. Citrate and Ca²⁺ concentrations were measured pre and post albumin filter as well as pre and post adsorbents. In addition, batch experiments were performed to quantify citrate adsorption.

RESULTS

Pre albumin filter target Ca²⁺ concentrations were reached well with only minor deviations. Citrate was adsorbed by anion exchange resins, resulting in a higher Ca²⁺ concentration downstream of the adsorbent cartridges during the first hour of treatment.

CONCLUSIONS

The anion exchange resin depletes citrate, leading to an increased Ca²⁺ concentration in the extracorporeal circuit, which may cause an increased risk of clotting during the first hour of treatment. An increase of citrate infusion during the first hour of treatment should therefore be considered to compensate for the adsorption of citrate.

Large-scale Multi-omic Analysis of COVID-19 Severity

We performed RNA-Seq and high-resolution mass spectrometry on 128 blood samples from COVID-19 positive and negative patients with diverse disease severities. Over 17,000 transcripts, proteins, metabolites, and lipids were quantified and associated with clinical outcomes in a curated relational database, uniquely enabling systems analysis and cross-ome correlations to molecules and patient prognoses. We mapped 219 molecular features with high significance to COVID-19 status and severity, many involved in complement activation, dysregulated lipid transport, and neutrophil activation. We identified sets of covarying molecules, e.g., protein gelsolin and metabolite citrate or plasmalogens and apolipoproteins, offering pathophysiological insights and therapeutic suggestions. The observed dysregulation of platelet function, blood coagulation, acute phase response, and endotheliopathy further illuminated the unique COVID-19 phenotype. We present a web-based tool (covid-omics.app) enabling interactive exploration of our compendium and illustrate its utility through a comparative analysis with published data and a machine learning approach for prediction of COVID-19 severity.

Long-term mortality risk associated with citric acid- and acetic acid-based bicarbonate haemodialysis: a historical cohort propensity score-matched study in a large, multicentre, population-based study

Background

Citric acid-based bicarbonate dialysate (CiD) is increasingly used in haemodialysis (HD) to improve haemodynamic tolerance and haemocompatibility associated with acetic acid-based bicarbonate dialysate. Safety concerns over CiD have been raised recently after a French ecological study reported higher mortality hazard in HD clinics with high CiD consumption. Therefore, we evaluated the mortality risk associated with various acidifiers (AcD, CiD) of bicarbonate dialysate.

Methods

In this multicentre, historical cohort study, we included adult incident HD patients (European, Middle-East and Africa Fresenius Medical Care network; 1 January 2014 to 31 October 2018). We recorded acidifiers of bicarbonate dialysis and dialysate composition for each dialysis session. In the primary intention-to-treat analysis, patients were assigned to the exposed group if they received CiD in &gt;70% of sessions during the first 3 months (CiD70%), whereas the non-exposed group received no CiD at all. In the secondary analysis, exposure was assessed on a monthly basis for the whole duration of the follow-up.

Results

We enrolled 10 121 incident patients during the study period. Of them, 371 met the criteria for inclusion in CiD70%. After propensity score matching, mortality was 11.43 [95% confidence interval (CI) 8.86–14.75] and 12.04 (95% CI 9.44–15.35) deaths/100 person-years in the CiD0% and CiD70% groups, respectively (P = 0.80). A similar association trend was observed in the secondary analysis.

Conclusions

We did not observe evidence of increased mortality among patients exposed to CiD in a large European cohort of dialysis patients despite the fact that physicians were more inclined to prescribe CiD to subjects with worse medical conditions.

Increasing the Magnesium Concentration in Various Dialysate Solutions Differentially Modulates Oxidative Stress in a Human Monocyte Cell Line

Oxidative stress is exacerbated in hemodialysis patients by several factors, including the uremic environment and the use of dialysis fluids (DFs). Since magnesium (Mg) plays a key role in modulating immune function and in reducing oxidative stress, we aimed to evaluate whether increasing the Mg concentration in different DFs could protect against oxidative stress in immunocompetent cells in vitro. Effect of ADF (acetate 3 mM), CDF (citrate 1 mM), and ACDF (citrate 0.8 mM + acetate 0.3 mM) dialysates with Mg at standard (0.5 mM) or higher (1, 1.25, and 2 mM) concentrations were assessed in THP-1 monocyte cultures. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were quantified under basal and uremic conditions (indoxyl sulfate (IS) treatment). Under uremic conditions, the three DFs with 0.5 mM Mg promoted higher ROS production and lipid damage than the control solution. However, CDF and ACDF induced lower levels of ROS and MDA, compared to that induced by ADF. High Mg concentration (1.25 and/or 2 mM) in CDF and ACDF protected against oxidative stress, indicated by reduced ROS and MDA levels compared to respective DFs with standard concentration of Mg. Increasing Mg concentrations in ADF promoted high ROS production and MDA content. Thus, an increase in Mg content in DFs has differential effects on the oxidative stress in IS-treated THP-1 cells depending on the dialysate used.

Joint Toxicity of a Multi-Heavy Metal Mixture and Chemoprevention in Sprague Dawley Rats

To explore the joint toxicity and bio-accumulation of multi-heavy metals and potential chemoprevention strategies, Male Sprague Dawley (SD) rats (n = 30) were treated orally once a week for six months with 500mg/kg•bw of eight heavy metals which were commonly identified in aquatic products in the Ningbo area including chromium, manganese, nickel, copper, zinc, cadmium, mercury, and lead. At the same time, 200mg/kg•bw of epigallocatechin-3-gallate (EGCG), trisodium citrate dihydrate (TCD) or glutathione (GSH) were administered to evaluate their antagonistic effects against adverse effects of multi-heavy metal mixture. The Morris water maze test was used to evaluate spatial learning and memory in the treated rats. Then the rats were anesthetized by pentobarbital sodium (40 mg/kg•bw) to obtain blood samples for biochemical analysis and organs (heart, liver, spleen, lungs, kidneys, brain, testis) to be conducted for biopsy and organ coefficients. Inductively coupled plasma mass spectrometer (ICP-MS) was used to analyze the concentrations of heavy metals. Results indicated that six months of exposure to a multi-heavy metal mixture under this experimental dosage resulted in accumulation in organs and adverse effects on the blood, reproductive system, and liver function. EGCG, TCD or GSH all showed certain chemoprevention effects against the joint toxicity induced by the multi-heavy metal mixture and indicated alleviation and the potential mechanism that also included the promotion of excretion of metals to which animals were exposed.

Highly sensitive fluorescent carbon dots probe with ratiometric emission for the determination of ClO−

A ratiometric fluorescent N,S co-doped carbon dots (N,S-CD) probe for ClO⁻ has been facilely obtained via a one-step hydrothermal method.

Protective Effect of Ginkgolic Acid in Attenuating LDL Induced Inflammation Human Peripheral Blood Mononuclear Cells via Altering the NF-κB Signaling Pathway

Oxidized low-density lipoprotein (ox-LDL) is considered as the significant maker of inflammatory reaction. ox-LDL was reported to play a crucial role in the pathogenesis of atherosclerosis (AS). In the current study, we scrutinize the suppressive effect of ginkgolic acid against ox-LDL induced an oxidative and inflammatory response in human microvascular endothelial cells (HMEC-1) and human peripheral blood mononuclear cells (nPBMCs) and explore the mechanism of action. HMEC-1 cells are treated with ox-LDL in the presence of different concentration of ginkgolic acid. MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed for the estimation of cell viability effect. Reactive oxygen species (ROS), inflammatory cytokines, and NF-κB activity are also estimated. For the hPBMCs assay, the cells were isolated from the healthy volunteers and cultured. The cells were further divided into different group and received the ginkgolic acid. Additionally, ROS, inflammatory marker such as prostaglandin E2 (PGE2), lipoxygenase (LOX), nitric oxide (NO), cyclooxygenase (COX) protein expression, and mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion protein 1 (VCAM-1) were estimated in the ox-LDL treated group. The result exhibited that ginkgolic acid treatment induced the cell viability boosting in ox-LDL treatment and intracellular ROS significantly decreased by ginkgolic acid. Pro-inflammatory cytokines also downregulated via ginkgolic acid. Moreover, ginkgolic acid reduced the ox-LDL-induced NF-κB. The mRNA and protein expression of TNF-α, IL-6, and VCAM-1 considerably increased in the ox-LDL treated group and ginkgolic acid significantly reduced the mRNA and protein expression. An inflammatory marker such as PGE2, LOX, and NO were increased in the ox-LDL treated group and ginkgolic acid treated group exhibited the reduction of an inflammatory marker. Based on the result, we can conclude that ginkgolic acid significantly reduced and reversed the ox-LDL-induced modulation, suggesting its anti-inflammatory effect via the NF-κB pathway.

Renal clearance of heparin-binding protein and elimination during renal replacement therapy: Studies in ICU patients and healthy volunteers

Background

Heparin-binding protein (HBP) is released by neutrophils upon activation, and elevated plasma levels are seen in inflammatory states like sepsis, shock, cardiac arrest, and burns. However, little is known about the elimination of HBP. We wanted to study renal clearance of HBP in healthy individuals and in burn patients in intensive care units (ICUs). We also wished to examine the levels of HBP in the effluent of renal replacement circuits in ICU patients undergoing continuous renal replacement therapy (CRRT).

Methods

We measured plasma and urine levels of HBP and urine flow rate in 8 healthy individuals and 20 patients in a burn ICU. In 32 patients on CRRT, we measured levels of HBP in plasma and in the effluent of the CRRT circuit.

Results

Renal clearance of HBP (median (IQR) ml/min) was 0.19 (0.08–0.33) in healthy individuals and 0.30 (0.01–1.04) in burn ICU patients. In ICU patients with cystatin C levels exceeding 1.44 mg/l, clearance was 0.45 (0.15–2.81), and in patients with cystatin C below 1.44 mg/l clearance was lower 0.28 (0.14–0.55) (p = 0.04). Starting CRRT did not significantly alter plasma levels of HBP (p = 0.14), and the median HBP level in the effluent on CRRT was 9.1 ng/ml (IQR 7.8–14.4 ng/ml).

Conclusion

In healthy individuals and critically ill burn patients, renal clearance of HBP is low. It is increased when renal function is impaired. Starting CRRT in critically ill patients does not alter plasma levels of HBP significantly, but HBP can be found in the effluent.

It seems unlikely that impaired kidney function needs to be considered when interpreting concentrations of HBP in previous studies. Starting CRRT does not appear to be an effective way of reducing HBP concentrations.

Citrate anion improves chronic dialysis efficacy, reduces systemic inflammation and prevents Chemerin-mediated microvascular injury

Systemic inflammation and uremic toxins (UT) determine the increased cardiovascular mortality observed in chronic hemodialysis (HD) patients. Among UT, the adipokine Chemerin induces vascular dysfunction by targeting both endothelial and vascular smooth muscular cells (EC and VSMC). As Citrate anion modulates oxidative metabolism, systemic inflammation and vascular function, we evaluated whether citrate-buffered dialysis improves HD efficiency, inflammatory parameters and chemerin-mediated microvascular injury. 45 patients were treated in sequence with acetate, citrate and, again, acetate-buffered dialysis solution (3 months per interval). At study admission and after each treatment switch, we evaluated dialysis efficacy and circulating levels of chemerin and different inflammatory biomarkers. In vitro, we stimulated EC and VSMC with patients’ plasma and we investigated the role of chemerin as UT. Citrate dialysis increased HD efficacy and reduced plasma levels of CRP, fibrinogen, IL6 and chemerin. In vitro, patients’ plasma induced EC and VSMC dysfunction. These effects were reduced by citrate-buffered solutions and paralleled by the decrease of chemerin levels. Consistently, chemerin receptor knockdown reduced EC and VSMC dysfunction. In conclusion, Switching from acetate to citrate improved dialysis efficacy and inflammatory parameters; in vitro, chemerin-induced EC and VSMC injury were decreased by using citrate as dialysis buffer.

Proteins adsorbed to a polysulfone hemodialysis membrane under heparin and citrate anticoagulation regimens

The study aim was to compare molecular-level effects (blood-dialyzer interactions) of heparin and citrate anticoagulation using proteome-wide analysis of biofilm adsorbed to dialysis membrane. Ten patients receiving maintenance hemodialysis were examined in a crossover design under three different anticoagulation regimens, namely citrate, heparin, and anticoagulation-free (control). Following a regular hemodialysis session (4 hours, polysulfone membrane), dialyzers were flushed and the surface biofilm eluted by acetic acid. Protein composition of the eluates was determined by 2-dimensional gel electrophoresis and resulting patterns compared between regimens. Proteins responsible for the difference were identified by mass spectrometry. Citrate anticoagulation was associated with significantly less protein adsorption to the membrane than heparin (2.2 [1.1-2.9] mg vs. 6.5 [2.9-11.6] mg, P = 0.009). Among the proteins identified as major discriminators between citrate and the other regimens, fibrin α-chain fragments of molecular weight below 40 kDa prevailed. In these fragments, an analysis of the amino acid sequence has been performed by comparison with the UniProt database. It showed missing α-chain cross-links. On the contrary, heparin prevented adsorption and cleavage of several heparin-binding proteins; especially complement factor H-related protein 3, insulin-like growth factor binding proteins (2, 4, and 5), and chemerin. Compared to heparin, citrate is associated with less protein adsorption and imperfectly crosslinked fibrin clot formation. Membrane adsorptive properties are significantly modified by the anticoagulation regimen.

Biocompatibility of Hemodialysis

This study was designed to investigate the biocompatibility of hemodialysis procedures, largely depending on the contact of patient's blood with the dialysis membranes. We addressed the issue by comparing the content of the proteolytic enzymes collagenase and cathepsin B and that of neutrophil myeloperoxidase (MPO) and C-reactive protein (CRP) in the blood before and after a single session treatment and a full course of successive 8-week-long therapies with three types of hemodialysis: low-flux (lfHD), high-flux (hfHD), and post-dilution hemodiafiltration (HDF). The study included 19 patients with chronic nephropathy. We found that collagenase significantly increased after a single session of each type of hemodialysis. Cathepsin B tended to decrease after single sessions; the decrease reached significance only after hfHD. CRP increased significantly after single hfHD and HDF treatments. These changes were meager, with no differences depending on the dialysis type, and their significance was lost after 8-week-long therapy, except the persisting increase in CRP after HDF. Neutrophil MPO apparently was not activated during any type of dialysis, as its content was below the detection threshold. We conclude that all three types of hemodialysis are compatible with the biological system, so that they would rather unlikely lead to clinically harmful effects in chronically hemodialyzed patients. Nonetheless, proteolytic enzymes and myeloperoxidase seem hardly appropriable estimators of hemodialysis biocompatibility due to meager and variable changes. Upregulation of C-reactive protein, on the other hand, expresses a general pro-inflammatory propensity of hemodialysis and is not a suitable estimator of biocompatibility either.

Citrate reduced oxidative damage in stem cells by regulating cellular redox signaling pathways and represent a potential treatment for oxidative stress-induced diseases

Chemical substances containing citrate such as calcium citrate, citrate esters and citric acid exhibit anti-oxidant and anti-inflammatory properties in different cells and tissues. However, data on the anti-oxidant and anti-inflammatory properties and mechanisms of action of citrate are insufficient. In this study, we systematically evaluated the anti-oxidant capacity of citrate using chemical, cellular and animal assays. Citrate showed a stable molecular structure and did not directly react with oxides. Citrate exerted protective and anti-apoptotic effects on BMSCs and also showed significant inhibitory effects on the oxidative stress and inflammatory reactions in the rat air pouch model. By using proteomics, we found that PPARγ contributed to the upregulation of various free radical scavenging proteins and the downregulation of diverse components of the inflammatory responses. Citrate-regulated global PPARγ expression was evidenced by the significant increase expression of PPARγ in PC12 cell line. Our results provide novel insights into the role of citrate in regulating cellular redox signaling and the function of PPARγ signaling in this process and also provide basic molecular cell biology information to improve the applications of biomaterials or stem cells as treatments for oxidative stress-induced degenerative diseases and inflammatory diseases.

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Citrate exerts anti-oxidant and anti-inflammatory properties in BMSCs and tissues.

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Citrate can upregulate and downregulate anti-oxidant and anti-inflammatory proteins in BMSCs.

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Citrate can regulate anti-oxidant and anti-inflammatory proteins via PPARγ dependent and independent pathways.

Oxidative stress in hemodialysis: Causative mechanisms, clinical implications, and possible therapeutic interventions

Oxidative stress (OS) is the result of prooxidant molecules overwhelming the antioxidant defense mechanisms. Hemodialysis (HD) constitutes a state of elevated inflammation and OS, due to loss of antioxidants during dialysis and activation of white blood cells triggering production of reactive oxygen species. Dialysis vintage, dialysis methods, and type and condition of vascular access, biocompatibility of dialyzer membrane and dialysate, iron administration, and anemia all can play a role in aggravating OS, which in turn has been associated with increased morbidity and mortality. Oral or intravenous administration of antioxidants may detoxify the oxidative molecules and at least in part repair OS-mediated tissue damage. Lifestyle interventions and optimization of a highly biocompatible HD procedure might ameliorate OS development in dialysis.

Citrate dialysate does not induce oxidative stress or inflammation in vitro as compared to acetate dialysate

Increased acetataemia during haemodialysis sessions has been associated with a number of abnormalities, including increased oxidative stress, pro-inflammatory cytokines and nitric oxide synthesis. However, citric acid may play an alternative role to acetate as a dialysate stabiliser given that the effect of citrate on complement and leukocyte activation is different to that of acetate. The purpose of this study was to compare the inflammatory effect in immunocompetent blood cells of acetate dialysate and citrate dialysate.

MATERIAL AND METHODS

The effect of acetate and/or citrate was investigated in the whole blood of uraemic patients and in healthy in vitro samples. Four types of dialysate were tested: dialysate 1, acetate-free with 1mmol/L of citrate; dialysate 2, with 0.8mmol/L of citrate and 0.3mmol/L of acetate; dialysate 3, citrate-free with 3mmol/L of acetate; and dialysate 4, citrate-free with 4mmol/L of acetate. The cell types used were: human monocyte culture (THP-1); and peripheral blood mononuclear cells (PBMCs) from healthy subjects and uraemic patients on haemodialysis. ICAM-1 was determined and levels of reactive oxygen species and total microvesicles were quantified.

RESULTS

Unlike the citrate dialysates, the dialysates with acetate (dialysate 3 and dialysate 4) induced increased ICAM-1 expression density in THP-1 cells; an increase in ICAM-1 expression was observed in the immunocompetent cells of healthy subjects with acetate dialysate (dialysate 3 and dialysate 4) but not with citrate dialysate (dialysate 1 and dialysate 2). No significant ICAM-1 differences were found between the different dialysates in the cells of haemodialysed patients. Reactive oxygen species expression and the number of microvesicles increased significantly with acetate dialysate but not with citrate dialysate in the cells of both healthy subjects and haemodialysed patients.

CONCLUSIONS

At the concentrations in which it is generally used in clinical practice, acetate-based dialysate increases oxidative stress and the total number of microvesicles and may induce other pro-inflammatory stimuli typical of uraemic patients on haemodialysis. Citrate dialysates do not induce this activation, which could make them a suitable alternative in clinical practice.

Influence of citrate concentration on the activation of blood cells in an in vitro dialysis setup

Background

Regional citrate anticoagulation has been associated with enhanced biocompatibility in hemodialysis, but the optimal dose of citrate remains to be established. Here, we compared parameters related to cellular activation during in vitro dialysis, using two doses of citrate.

Methods

Human whole blood, anticoagulated with either 3 mM or 4 mM of citrate, was recirculated in an in vitro miniaturized dialysis setup. Complement (C3a-desArg), soluble platelet factor 4 (PF4), thromboxane B2 (TXB2), myeloperoxidase (MPO), as well as platelet- and red blood cell-derived extracellular vesicles (EV) were quantified during recirculation. Dialyzer fibers were examined by scanning electron microscopy after recirculation to assess the activation of clotting and the deposition of blood cells.

Results

Increases in markers of platelet and leukocyte activation, PF4, TXB2, and MPO were comparable between both citrate groups. Complement activation tended to be lower at higher citrate concentration, but the difference between the two citrate groups did not reach significance. A strong increase in EVs, particularly platelet-derived EVs, was observed during in vitro dialysis for both citrate groups, which was significantly less pronounced in the high citrate group at the end of the experiment. Assessment of dialyzer clotting scores after analysis of individual fibers by scanning electron microscopy revealed significantly lower scores in the high citrate group.

Conclusions

Our data indicate that an increase in the citrate concentration from 3 mM to 4 mM further dampens cellular activation, thereby improving biocompatibility. A concentration of 4 mM citrate might therefore be optimal for use in clinical practice.

[Regional citrate anticoagulation in renal replacement therapy in the intensive care station : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]

BACKGROUND

Regional citrate anticoagulation (RCA) in continuous renal replacement therapy can effectively anticoagulate dialysis circuits without having adverse effects on systemic heparin application. In particular, in continuous renal replacement therapy RCA is well established and represents a safe procedure with longer filter lifetimes and fewer bleeding complications.

OBJECTIVES

To provide guidance on the indications, advantages and disadvantages, and use of RCA, current recommendations from the renal section of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated.

MATERIALS AND METHODS

The recommendations in this paper are based on the current KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, other published guidelines and protocols as well as the expert knowledge and clinical experience of the authors.

RESULTS

The use of commercially available machines with coupled pumps and integrated safety features, effective personal training and standardized protocols for clinical usage (SOP) is particularly important for the safe clinical use of RCA in renal replacement therapy. Contrary to previous recommendations, even liver failure or shock with lactic acidosis may no longer be an absolute contra-indication for RCA. However, these particular patients have to be carefully monitored for signs of citrate accumulation.

Regional Citrate Anticoagulation for Hemodialysis: Calcium-Free Vs. Calcium Containing Dialysate - A Randomized Trial

Background

The majority of citrate protocols for hemodialysis (HD) use calcium (Ca)-free dialysate, a limited number use dialysate with Ca, aiming to simplify the procedure. This randomized clinical study sought to compare the anticoagulant effect of citrate using Ca-free dialysate and dialysate with Ca 1.25 mmol/L.

Methods

Fifty HD procedures (in 5 chronic HD patients treated by chronic citrate anticoagulation) were randomly assigned to Ca-free dialysate (25 procedures) or Ca-1.25 dialysate (25 procedures), both with Mg 0.5 mmol/L, Na 138 mmol/L, and bicarbonate 28 mmol/L. Ca-free HD: 15% Na3 citrate 80 ml/hour was infused into the arterial line, and 1 M CaCl2, 14 ml/hour into the venous line. Ca-1.25 group: 15% Na3 citrate 100 ml/hour, 1 M CaCl2 2–4 ml/hour. Polyflux H dialyzers were used. Antithrombotic effect was assessed visually after HD at 3 points: dialyzer, arterial, and venous bubble traps, using a score of 5 (no clotting) to 1 (total clotting).

Results

Ca-free group: arterial bubble trap score 4.7 ± 0.5, dialyzer 4.5 ± 0.6, venous bubble trap 4.8 ± 0.6. Ionized calcium (iCa) at dialyzer inlet 0.34 ± 0.17, outlet 0.21 ± 0.06 mmol/L. All HDs were completed successfully. Ca-1.25 group: arterial bubble trap score 4.7 ± 0.5 (NS), dialyzer 2.6 ± 1.04 (p<0.01), venous bubble trap 2.4 ± 0.9 (p<0.01). Volume of clot in venous bubble trap was 1.9 ± 1.8 mL (range 0.5–6 mL). iCa at dialyzer inlet 0.24 ± 0.05 mmol/L (p<0.05), outlet 0.63 ± 0.11 mmol/L (p<0.01). Four of 25 HD procedures (16%) were prematurely terminated due to threatening dialyzer clotting, in 6/25 HD procedures (24%), the venous line was changed (p<0.01).

Conclusion

Citrate anticoagulation with Ca-1.25 dialysate resulted in significantly worse anticoagulation of dialyzer and venous bubble trap compared with Ca-free dialysate, despite higher citrate dose.

Heparin-Free Prolonged Intermittent Hemodialysis Using Calcium-Free Citrate Dialysate in Critically Ill Patients

OBJECTIVES

Critically ill patients who have a high risk of bleeding but require prolonged intermittent dialysis need a heparin-free easy-to-use alternative type of anticoagulation within the dialysis circuit. We assessed the safety and efficiency of heparin-free regional citrate anticoagulation of the dialysis circuit using a calcium-free citrate-containing dialysate, with calcium reinjected according to ionic dialysance.

DESIGN

Prospective cohort study.

SETTING

Critical care units.

PATIENTS

Critically ill patients who required renal replacement therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 101 dialysis sessions were performed in 35 patients (mechanical ventilation n = 78; norepinephrine n = 13). Median duration of dialysis was 294 minutes (interquartile range, 240-300), and median ultrafiltration volume was 2.3 L (1-2.8). Urea and β2-microglobulin reduction rates were 64.5% ± 0.4% and 48% ± 0.13%, respectively. Postfilter ionized calcium was 0.35 ± 0.17 and 0.38 ± 0.14 mmol/L at 1 and 3 hours, respectively, within the extracorporeal circuit. A major clotting event that led to premature termination of the session occurred in only three of 101 sessions. In these three cases, major catheter dysfunction occurred before clotting within the circuit. Prefilter ionized calcium remained within narrow ranges (before/after change +0.07 ± 0.006 mmol/L), and total-to-ionized calcium ratio, a surrogate marker for citratemia, was unchanged.

CONCLUSIONS

Dialysis anticoagulation with calcium-free citrate-containing dialysate and calcium reinjection according to ionic dialysance is an easy-to-use, efficient, and inexpensive form of heparin-free regional anticoagulation. It allows prolonged hemodialysis sessions in critically ill patients without the need to systemically monitor ionized calcium. Furthermore, sessions can be safely extended according to the hemodynamic tolerance to ensure an adequate dose of dialysis and a negative water balance, a major point in patients with severe acute kidney disease.

Peripheral blood microvesicles secretion is influenced by storage time, temperature, and anticoagulants

Microvesicles (MVs) are small membrane bound vesicles released from various cell types after activation or apoptosis. In the last decades, MVs received an increased interest as biomarkers in inflammation, coagulation and cancer. However, standardized pre-analytical steps are crucial for the minimization of artifacts in the MV analysis. Thus, this study evaluated the MV release in whole blood samples under the influence of different anticoagulants, storage time and various temperature conditions. Samples were collected from healthy probands and processed immediately, after 4, 8, 24 and 48 hours at room temperature (RT) or 4°C. To identify MV subpopulations, platelet free plasma (PFP) was stained with Annexin V, calcein AM, CD15, CD41 and CD235a. Analysis was performend on a CytoFLEX flow cytometer. Procoagulatory function of MVs was measured using a phospholipid dependent activity and a tissue factor MVactivity assay. Without prior storage, sodium citrate showed the lowest MV count compared to heparin and EDTA. Interestingly, EDTA showed a significant release of myeloid-derived MVs (MMVs) compared to sodium citrate. Sodium citrate showed a stable MV count at RT in the first 8 hours after blood collection. Total MV counts increased after 24 hours in sodium citrated or heparinzed blood which was related to all subpopulations. Interestingly, EDTA showed stable platelet-derived MV (PMV) and erythrocyte-derived MV (EryMV) count at RT over a 48 h period. In addition, the procoagulatory potential increased significantly after 8-hour storage. Based on both, this work and literature data, the used anticoagulant, storage time and storage temperature differently influence the analysis of MVs within 8 hours. To date, sodium citrated tubes are recommended for MV enumeration and functional analysis. EDTA tubes might be an option for the clinical routine due to stable PMV and EryMV counts. These new approaches need to be validated in a clinical laboratory setting before being applied to patient studies. © 2016 International Society for Advancement of Cytometry.

Is Regional Citrate Anticoagulation the Future of Hemodialysis?

Citrate has many characteristics of the ideal anticoagulant for hemodialysis. In addition to immediate and complete anticoagulation in the dialysis circuit, citrate has important effects beyond anticoagulation, mainly in reducing inflammatory response induced by hemodialysis. Citrate has already become the standard anticoagulant in acute kidney injury requiring continuous renal replacement therapy (CRRT), both for adults and children, with the citrate module being a part of modern CRRT monitors. Although the citrate module is not yet available for intermittent hemodialysis, precise infusion pumps, point-of-care ionometers and high citrate clearance from high flux dialyzers increase safety while reducing the risk of metabolic complications, both in adult and pediatric patients. Slovenia has a long tradition, high volume and expansion of citrate use in hemodialysis, including long-term citrate anticoagulation in selected patients. At the Department of Nephrology, University Medical Centre Ljubljana, more than 10 000 citrate procedures were performed in 2015. We believe that regional citrate anticoagulation may replace heparin as the main anticoagulant for intermittent hemodialysis in the not so distant future.

Oxidative Stress in Hemodialysis Patients: A Review of the Literature

Hemodialysis (HD) patients are at high risk for all-cause mortality and cardiovascular events. In addition to traditional risk factors, excessive oxidative stress (OS) and chronic inflammation emerge as novel and major contributors to accelerated atherosclerosis and elevated mortality. OS is defined as the imbalance between antioxidant defense mechanisms and oxidant products, the latter overwhelming the former. OS appears in early stages of chronic kidney disease (CKD), advances along with worsening of renal failure, and is further exacerbated by the HD process per se. HD patients manifest excessive OS status due to retention of a plethora of toxins, subsidized under uremia, nutrition lacking antioxidants and turn-over of antioxidants, loss of antioxidants during renal replacement therapy, and leukocyte activation that leads to accumulation of oxidative products. Duration of dialysis therapy, iron infusion, anemia, presence of central venous catheter, and bioincompatible dialyzers are several factors triggering the development of OS. Antioxidant supplementation may take an overall protective role, even at early stages of CKD, to halt the deterioration of kidney function and antagonize systemic inflammation. Unfortunately, clinical studies have not yielded unequivocal positive outcomes when antioxidants have been administered to hemodialysis patients, likely due to their heterogeneous clinical conditions and underlying risk profile.

Hemofiltration induces generation of leukocyte-derived CD31+/CD41- microvesicles in sepsis

BACKGROUND

Microvesicles (MV) are extracellular vesicles known to be associated with cellular activation and inflammation. Hemofiltration is an effective blood purification technique for patients with renal failure and possibly also eliminates inflammatory mediators in the setting of sepsis. On the other hand, proinflammatory stimuli are induced by blood contacting the artificial membrane during extracorporeal blood purification. In chronic dialysis patients a systemic increase in MV has been described. The aim of the study was to investigate whether hemofilter passage of blood in continuous veno-venous hemofiltration (CVVH) alters MV composition and levels in critically ill patients with sepsis.

METHODS

Pre- and postfilter bloods as well as ultrafiltrate samples from intensive care unit patients with severe sepsis were obtained during CVVH with regional citrate anticoagulation. MV subtypes in blood were analyzed by high-sensitivity flow cytometry. Additionally, tissue factor (TF) levels and MV-associated TF activities as well as MV activities were quantified. All parameters were corrected for hemoconcentration applied during CVVH.

RESULTS

Twelve patients were analyzed. A significant increase in presumably mostly leukocyte-derived CD31+/CD41- MV (1.32 (1.09-1.93)-fold [median (25th-75th quartiles)], p = 0.021) was observed post- to prefilter, whereas platelet-derived MV as well as AnnexinV-binding MV were unaltered. Increments of AnnexinV+, CD42b+ and CD31+/CD41- MV post- to prefilter correlated with filtration fraction (FF) (all p < 0.05). Significant reductions in MV activity [0.72 (0.62-0.84)-fold, p = 0.002] and TF level [0.95 (0.87-0.99)-fold, p = 0.0093] were detected postfilter compared to prefilter. No MV activity was measurable in ultrafiltrate samples.

CONCLUSIONS

Despite clearing a fraction of small PS-exposing MV CVVH does not eliminate larger MV. Concurrently, CVVH induces the release of CD31+/CD4- MV that indicate leukocyte activation during hemofilter passage in septic patients. Increments of several MV subtypes within the hemofilter correlate with FF, which supports common recommendations to keep FF low. A fraction of TF is being cleared by CVVH via ultrafiltration.

Effectiveness and Safety Assessment of Citrate Anticoagulation During Albumin Dialysis in Comparison to Other Methods of Anticoagulation

Liver failure is a serious and often deadly disease often requiring MARS (Molecular Adsorbent Recirculating System) therapy. Choosing the safe and effective method of anticoagulation during artificial liver support systems seems to be very difficult and extremely important. The aim of this study was to assess effectiveness and safety of regional anticoagulation with citrate in liver failure patients during MARS. We used a single center observational study. We analyzed 158 MARS sessions performed in 65 patients: 105 (66.5%) sessions in 41 patients with heparin anticoagulation, 40 (25.3%) sessions in 19 patients with citrate, and 13 (8%) sessions in only five patients without anticoagulation, that were excluded from part of the analysis. To determine the effectiveness of regional anticoagulation with citrate, probability of filter survival and changes in laboratory parameters were analyzed according to the applied method of anticoagulation. The safety of citrate was determined by Ca/Ca²⁺ ratio, acid-base balance, bleeding complications, and the need for blood product transfusions. The probability of filter survival in the citrate group was 94% and in the heparin group 82% (P = 0.204). There was no relationship between the method of anticoagulation and effectiveness of MARS therapy in lowering the levels of the analyzed parameters. Only one patient had a Ca/Ca²⁺ ratio higher than he safety margin. There were no statistically significant changes in pH and lactate level irrespective of anticoagulation; bicarbonate dropped significantly only in the heparin group (P = 0.03). The frequency of bleeding complications and the need for transfusions did not differ significantly between groups. Regional anticoagulation with citrate can be an effective and safe method of anticoagulation during MARS therapy, but requires attentive monitoring and further studies in liver failure patients.

Comparison of the AN69ST Membrane versus Citrate-Enriched Dialysate on Clotting Events during Hemodialysis without Systemic Anticoagulation

BACKGROUND

The optimal management of anticoagulation in hemodialyzed patients with a high risk of bleeding is controversial.

METHODS

We compared premature termination of dialysis caused by clotting events between AN69ST membranes (G1) and 0.8 mmol/L citrate-enriched dialysate (G2). The number of sessions that had increased venous pressure (VP) and variations in urea-reduction ratio (URR) were analyzed.

RESULTS

Six hundred and two sessions were analyzed in 259 patients: 22.4% had sessions that ended prematurely (25% in G1 and 19.1% in G2, p = ns, OR 0.60 [0.34-1.08], p = 0.08). The increase in VP was lower in G2 (23 vs. 70, p < 0.001). URR was higher in G2 (0.56 vs. 0.60, p < 0.001).

CONCLUSION

Clotting events that led to the termination of dialysis were comparable in the 2 groups. However, UUR was better in G2, and the number of patients with increased VP in the sessions was lower in G2.

SHORT SUMMARY

Our study compared the effects of the AN69ST membrane and citrate-enriched dialysate on clotting events during the dialysis of 259 patients with a high risk of bleeding. URR was significantly better and fewer cases of increased VP occurred in the citrate group compared to the AN69 ST group. No significant difference was observed regarding the need to prematurely terminate a dialysis session.

A new prescription model for regional citrate anticoagulation in therapeutic plasma exchanges

Background

Regional citrate anticoagulation (RCA) is proposed for various extracorporeal purification techniques to overcome the risk of bleeding that might result from systemic anticoagulation. Yet, no individualized treatment protocol has been proposed for therapeutic plasma exchange (TPE) so far. The objective of this study was to assess the determinants of blood citrate concentration needed and to develop an individualized RCA protocol useful for clinical practice.

Methods

The study population included 14 patients who underwent a total of 47 TPE sessions. Citrate was infused pre-plasmafilter. Post-plasmafilter and systemic plasma ionized calcium concentrations were measured at standardized time intervals. An algorithm was proposed for the supplementation of calcium. During the discovery phase, citrate was infused at a fixed starting rate, and adapted accordingly to obtained post-plasmafilter ionized calcium levels. Using a mathematical approach, an algorithm was thereafter developed for individualized prescriptions of citrate.

Results

Pre-treatment values of hematocrit and plasma ionized calcium were the main determinants of the required rate of citrate infusion. These can be integrated into a final equation enabling to individualize the prescription. A prefilter ionized calcium concentration between 0.24 and 0.33 mmol/l prevented coagulation of the extracorporeal circuit. Significant hypocalcemia occurred in 8.5% of treatments. There were no significant acid–base disturbances.

Conclusion

We propose a new protocol, which enables for the first time to individualize the prescription of regional citrate anticoagulation during TPE, in an efficient manner. The immediately obtained regional anticoagulation protects against both the risk of coagulation of the membrane and the exposure to an excess of citrate.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0494-9) contains supplementary material, which is available to authorized users.

The role of ionized calcium and magnesium in regional citrate anticoagulation and its impact on inflammatory parameters

INTRODUCTION

Regional anticoagulation with citrate has been found to be superior to heparin in terms of biocompatibility, and numerous protocols for regional citrate anticoagulation have been published, while a consensus on the target concentration of ionized calcium (Ca2+) in the extracorporeal circuit has not been reached so far.

METHODS

The aim of this in vitro study was to assess the impact of different citrate concentrations on coagulation as well as on complement activation and cytokine secretion and to investigate the impact of ionized magnesium (Mg2+) on these parameters.

RESULTS

We found that citrate effectively reduced coagulation, complement activation, and cytokine secretion in a dose-dependent manner and that a target Ca2+ concentration of 0.2-0.25 mM was required for efficient anticoagulation. Mg2+ triggered complement activation as well as interleukin (IL)-1β secretion in lipopolysaccharide (LPS)-stimulated whole blood in a dose-dependent manner and independently of Ca2+. Additionally, it was found to reduce activated clotting time (ACT) in samples with low Ca2+ levels, but not at physiological Ca2+.

CONCLUSIONS

Taken together, our data support the notion that regional citrate anticoagulation results in decreased release of inflammatory mediators in the extracorporeal circuit, requiring the depletion of both, Ca2+ and Mg2+.