Dextran-sulfate-adsorption of atherosclerotic lipoproteins from whole blood or separated plasma for lipid-apheresis—Comparison of performance characteristics with DALI and lipidfiltration

Post COVID and Apheresis - Where are we Standing?

A continual increase in cases of Long/Post COVID constitutes a medical and socioeconomic challenge to health systems around the globe. While the true extent of this problem cannot yet be fully evaluated, recent data suggest that up to 20% of people with confirmed SARS-CoV-2 suffer from clinically relevant symptoms of Long/Post COVID several weeks to months after the acute phase. The clinical presentation is highly variable with the main symptoms being chronic fatigue, dyspnea, and cognitive symptoms. Extracorporeal apheresis has been suggested to alleviate symptoms of Post/COVID. Thus, numerous patients are currently treated with apheresis. However, at present there is no data from randomized controlled trials available to confirm the efficacy. Therefore, physicians rely on the experience of practitioners and centers performing this treatment. Here, we summarize clinical experience on extracorporeal apheresis in patients with Post/COVID from centers across Germany.

Quantitative determination of dextran sulfate and pentosan polysulfate and their binding with protamine using chronopotentiometry with polyion-selective electrodes

We report for the first time a chronopotentiometric measurement of polyanions based on localized ion depletion at the sample/membrane interface at a characteristic transition time τ, using polymer membrane polyanion-selective electrodes. Chronopotentiometric transduction of polyions based on the measurement of transition time has analytically more attractive applications compared to the controlled-current reversible pulsed chronopotentiometric transduction based on electromotive force (emf) measurement. This is because traditional polyion-selective electrodes based on emf measurement intrinsically give nonlinear (sigmoidal) calibration curves. While these can be used for indirect determination of polyions via polyanion-polycation titrations, they are not convenient for direct quantitation. However, under chronopotentiometric measurement based on the measurement of transition time, the square root of the transition time τ is linearly related to the concentration of the polyion according to the Sand equation and can be used for a direct calibration-free rapid determination. In this work, we have measured the concentrations of dextran sulfate (DS) and pentosan polysulfate (PPS) using polyanion selective electrodes under chronopotentiometric method where the transition time was measured and controlled-current pulsed chronopotentiometric transductions, where the phase boundary potential (emf) was measured. In addition, the protamine-DS and the protamine-PPS binding ratios have been determined using both transductions. The protamine-PPS binding ratio was determined to be 1.51:1 by the titration method and 1.54:1 by chronopotentiometry. The protamine-DS binding ratio was determined to be 1.37:1 by the titration method and 1.41:1 by chronopotentiometry, showing excellent agreement between the two methods. These simple measurement methods of binding ratios between polysaccharides and polypeptides may become important tools for screening safer and more reliable antidotes for the newer and safer anticoagulants such as Low Molecular Weight Heparins(LMWHs) and also to determine the dosages of antidotes needed to neutralize the anticoagulant activity.

EarLy Elimination of Fatty Acids iN hypertriglyceridemia-induced acuTe pancreatitis (ELEFANT trial): Protocol of an open-label, multicenter, adaptive randomized clinical trial

INTRODUCTION

Acute pancreatitis (AP) is a life-threatening inflammatory disease, with no specific pharmacological treatment. However, concerning some etiologies, early specific intervention (such as ERCP in biliary AP) has proven to be remarkably beneficial. Hypertriglyceridemia (HTG) induces severe pancreatic damage by several direct (cellular damage) and indirect (deterioration of microcirculation) mechanisms. Published data suggest that early removal of triglycerides (TGs) and toxic free fatty acids (FFAs) may be advantageous; however, high-quality evidence is still missing in the literature.

METHODS

Design: ELEFANT is a randomized controlled, multicenter, international trial testing the concept that early elimination of TGs and FFAs from the blood is beneficial in HTG-AP. The study will be performed with the adaptive "drop-the-loser" design, which supports the possibility of dropping the inferior treatment arm, based on the results of the interim analysis. Patients with HTG-AP defined by TG level over 11.3 mmol/l (1000 mg/dL) are randomized into three groups: (A) patients who undergo plasmapheresis and receive aggressive fluid resuscitation; (B) patients who receive insulin and heparin treatment with aggressive fluid resuscitation; and (C) patients with aggressive fluid resuscitation. Please note that all intervention must be started within 48 h from the onset of abdominal pain. Exclusion criteria are designed logically to decrease the possibility of any distorting effects of other diseases. The composite primary endpoint will include both severity and mortality.

RESULTS

Our null hypothesis is that early elimination of HTG and FFAs reduces the risk of mortality and severity of AP. Sample size calculation suggests that 495 patients will need to be enrolled in order to confirm or reject the hypothesis with a 10% dropout, 80% power and 95% significance level. The general safety and quality checks required for high-quality evidence will be adhered to. The study will be organized between February 2020 and December 2025.

CONCLUSION

Our study would provide the first direct evidence for or against early intervention in HTG-induced AP.

Current Role of Lipoprotein Apheresis

Purpose of Review

Lipoprotein apheresis is a very efficient but time-consuming and expensive method of lowering levels of low-density lipoprotein cholesterol, lipoprotein(a)) and other apoB containing lipoproteins, including triglyceride-rich lipoproteins. First introduced almost 45 years ago, it has long been a therapy of “last resort” for dyslipidaemias that cannot otherwise be managed. In recent years new, very potent lipid-lowering drugs have been developed and the purpose of this review is to define the role of lipoprotein apheresis in the current setting.

Recent Findings

Lipoprotein apheresis still plays an important role in managing patients with homozygous FH and some patients with other forms of hypercholesterolaemia and cardiovascular disease. In particular, patients not achieving treatment goals despite modern lipid-lowering drugs, either because these are not tolerated or the response is insufficient. Recently, lipoprotein(a) has emerged as an important cardiovascular risk factor and lipoprotein apheresis has been used to decrease lipoprotein(a) concentrations in patients with marked elevations and cardiovascular disease. However, there is considerable heterogeneity concerning the recommendations by scientific bodies as to which patient groups should be treated with lipoprotein apheresis.

Summary

Lipoprotein apheresis remains an important tool for the management of patients with severe drug-resistant dyslipidaemias, especially those with homozygous FH.

Long-term follow-up of circulating oxidative stress markers in patients undergoing lipoprotein apheresis by Direct Adsorption of Lipids (DALI)

OBJECTIVE

Beyond its well-established efficacy in lowering atherogenic lipids and lipoproteins, DALI (Direct Adsorption of Lipids) apheresis has been shown to have acute anti-inflammatory and endothelium-protective effects. In the present study, we investigated long-term effects of DALI procedures on circulating oxidative stress markers.

METHODS

Thirteen patients involved in the study underwent regular DALI apheresis for nearly two years. At sessions 1, 40 and 80 conventional lipid status and changes of systemic oxidative stress markers (oxidized LDL, anti-oxidized LDL antibodies, advanced oxidation protein products (AOPP), and myeloperoxidase (MPO)) were examined.

RESULTS

DALI procedure efficiently reduced atherogenic lipids/lipoproteins. On day three after apheresis lipid parameters returned to pre-apheresis values. They showed no tendency to increase or to decrease over time. No significant differences were found between 1st, 40th and 80th sessions. In a similar way, levels of oxidative stress biomarkers acutely decreased after apheresis sessions and rebounded on day three after apheresis. No significant differences were observed between sessions 1, 40, and 80.

CONCLUSION

DALI apheresis repeatedly decreases atherogenic lipid/lipoprotein profile and oxidative stress biomarker levels during each session. Among all investigated parameters no longitudinal effects over two years could be observed.

Long-term therapeutic efficacy of lipoprotein apheresis on circulating oxidative stress parameters--A comparison of two different apheresis techniques

BACKGROUND

A chronic lipoprotein apheresis therapy leads to an expressed reduction in the incidence of cardiovascular events in high-risk patients. In addition to the elimination of atherogenic lipoproteins such as LDL and lipoprotein(a), an antioxidative effect of lipoprotein apheresis has been suspected.

OBJECTIVES AND METHODS

We investigated long-term biochemical effects in sixteen patients undergoing lipoprotein apheresis - lipid filtration (LF, n = 7) or dextran sulfate adsorption (DSA, n = 9). Systemic oxidative stress markers (blood phagocyte chemiluminescence, levels of oxidized LDL and antioxLDL antibodies) were examined at the 1st, 40th and 80th apheresis sessions.

RESULTS

In DSA patients, the 80th apheresis session was associated with significantly higher LDL cholesterol removal and lower HDL cholesterol deprivation as compared to LF patients. In contrast to LF patients, DSA patients showed a long-term progressive decrease in circulating oxidant generating activity as evaluated by whole blood chemiluminescence (p < 0.05). Moreover, a single LF apheresis session was associated with higher systemic generation of reactive oxygen species over time.

CONCLUSION

Compared to LF, long-term DSA apheresis is associated with a gradual reduction of circulating oxidative burden and may be considered a beneficial molecular mechanism of this technique.

Current situation of lipoprotein apheresis in Saxony

This paper summarizes the situation pertinent to treatment via lipoprotein apheresis in the federal state of Saxony, Germany in 2010. In total, 119 predominately male patients were treated in 10 centers; the majority of the patients was older than the mean age of the general population. Several risk factors were present, particularly a familial predisposition and hypertension. All patients had experienced cardiovascular events and the majority was taking statins. Patient data from the University Hospital Carl Gustav Carus in Dresden concurred with data derived from patients treated at nephrological practices. In the mean, patients attended the centers for about 6 years, the majority weekly. LDL cholesterol concentrations prior to apheresis were clearly higher than target levels; apheresis sessions decreased LDL cholesterol by 69%. Lipoprotein(a) levels could be measured in 75 patients and were effectively reduced by lipoprotein apheresis. In Saxony, 29 patients per 1 million inhabitants received lipoprotein apheresis, which is higher than the proportion of patients treated in Germany as a whole. The need for this extracorporeal treatment seems to be much greater than its current utilization. Among the patients only one homozygous patient with familial hypercholesterolemia was observed. Physicians should be actively informed about this therapeutic possibility to reduce the cardiovascular risk efficiently. The introduction of new drugs may alter the position of lipoprotein apheresis within the therapeutic spectrum.

Preparation of sulfonated porous carbon nanotubes/activated carbon composite beads and their adsorption of low density lipoprotein

The high level of low density lipoprotein (LDL) in plasma is the main cause of atherosclerosis. Hemoperfusion is an ideal therapy to lower the level of LDL in human blood system while therapeutic effect is determined by the adsorbent. The adsorbent must have suitable pore structure and specific functional groups. Carbon nanotubes (CNTs) could be a new adsorbent material because CNTs have high specific surface area and they can be modified by a variety of functional groups. Porous carbon composite beads with the CNTs and phenolic resin mixture were synthesized by suspension polymerization, following with carbonization and steam-activation. Then the porous composite beads were sulfonated with a sulfanilic acid anhydrous by diazotization and coupling reaction. The potential application of the sulfonated porous composite beads in adsorbing low density lipoprotein (LDL) from human serum was investigated. The results showed that the sulfonic acid groups on the composite beads could lower LDL levels greatly by electrostatic interaction with electropositive LDL. The higher 20-100 nm pore volume the composite beads had, the more LDL they could adsorb. The 20-100 nm pore volume was enhanced by adding more CNTs and improving CNTs dispersion (ultrasonic crushing). The sulfonated composite beads containing 45 wt% CNTs presented the highest adsorption capacity to LDL 10.46 mg/g, showing a good prospect as LDL adsorbent in hemoperfusion.

Different inflammatory responses induced by three LDL-lowering apheresis columns

Low-density lipoprotein (LDL) apheresis is well-established in selected patients with uncontrolled LDL levels. As such treatment affects biomarkers important in atherosclerosis and acute coronary syndromes, we systematically compared the inflammatory response induced by three LDL apheresis columns. Three patients with heterozygous familial hypercholesterolemia participated in a cross-over study with six consecutive treatments with three different LDL apheresis columns: DL-75 (whole blood adsorption), LA-15 (plasma adsorption), and EC-50W (plasma filtration). Biochemical parameters and inflammatory biomarkers, including complement activation products and 27 cytokines, chemokines, and growth factors were measured before and after treatment. Complement was activated through the alternative pathway. The final end product sC5b-9 increased significantly (P < 0.01) and equally with all devices, whereas the anaphylatoxins C3a and C5a were lower by use of the adsorption columns. Hs-CRP was reduced by 77% (DL-75), 72% (LA-15), and 43% (EC-50W). The cytokines were consistently either increased (IL-1ra, IP-10, MCP-1), decreased (IFN-gamma, TNF-alpha, RANTES, PDGF, VEGF), or hardly changed (including IL-6, IL8, MIP-1alphabeta) during treatment. The changes were in general less pronounced with the adsorption columns. All columns reduced LDL significantly and to the same extent. In conclusion, three LDL-apheresis devices with equal cholesterol-lowering effect differed significantly with respect to the inflammatory response.