Efficacy of different low-density lipoprotein apheresis methods

[Lipoprotein apheresis : State of the art and case report of the longest HELP treatment worldwide]

Lipoprotein apheresis is an extracorporeal procedure for the treatment of patients with homozygous familial hypercholesterolemia, patients with severe treatment-resistant hypercholesterolemia and patients with lipoprotein(a) hypercholesterolemia, who show progressive atherosclerotic cardiovascular disease despite optimal treatment. This article reports on the historical developments of the procedures, the most frequently used methods for apheresis as well as the data situation on efficacy and tolerability. Randomized prospective studies on clinical outcomes are not available. Furthermore, the article reports on a patient with homozygous familial hypercholesterolemia and 34 years of treatment with heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) apheresis, the longest treatment of this kind worldwide. A second patient with combined heterozygous familial hypercholesterolemia and 31 years of liposorber and HELP apheresis is also described. The observational studies and the case reports demonstrate the safety and long-term tolerability of the procedure.

Lipoprotein turnover and possible remnant accumulation in preeclampsia: insights from the Freiburg Preeclampsia H.E.L.P.-apheresis study

Background

Preeclampsia is a life-threatening disease in pregnancy, and its complex pathomechanisms are poorly understood. In preeclampsia, lipid metabolism is substantially altered. In late onset preeclampsia, remnant removal disease like lipoprotein profiles have been observed. Lipid apheresis is currently being explored as a possible therapeutic approach to prolong preeclamptic pregnancies. Here, apheresis-induced changes in serum lipid parameters are analyzed in detail and their implications for preeclamptic lipid metabolism are discussed.

Methods

In the Freiburg H.E.L.P.-Apheresis Study, 6 early onset preeclamptic patients underwent repeated apheresis treatments. Serum lipids pre- and post-apheresis and during lipid rebound were analyzed in depth via ultracentrifugation to yield lipoprotein subclasses.

Results

The net elimination of Apolipoprotein B and plasma lipids was lower than theoretically expected. Lipids returned to previous pre-apheresis levels before the next apheresis even though apheresis was repeated within 2.9 ± 1.2 days. Apparent fractional catabolic rates and synthetic rates were substantially elevated, with fractional catabolic rates for Apolipoprotein B / LDL-cholesterol being 0.7 ± 0.3 / 0.4 ± 0.2 [day^− 1] and synthetic rates being 26 ± 8 / 17 ± 8 [mg*kg^− 1*day^− 1]. The distribution of LDL-subclasses after apheresis shifted to larger buoyant LDL, while intermediate-density lipoprotein-levels remained unaffected, supporting the notion of an underlying remnant removal disorder in preeclampsia.

Conclusion

Lipid metabolism seems to be highly accelerated in preeclampsia, likely outbalancing remnant removal mechanisms. Since cholesterol-rich lipoprotein remnants are able to accumulate in the vessel wall, remnant lipoproteins may contribute to the severe endothelial dysfunction observed in preeclampsia.

Trial registration

ClinicalTrails.gov, NCT01967355.

Lipoprotein apheresis to treat elevated lipoprotein (a)

An elevated plasma concentration of lipoprotein (a) [Lp(a)] is an independent risk factor for cardiovascular disease. Life style modification and currently available drugs either fail to effectively lower plasma Lp(a) levels or do not result in clinical benefit. However, lipoprotein apheresis is very efficient in decreasing Lp(a) concentrations. A single apheresis session can acutely decrease Lp(a) by approximately 60-75%, and apheresis performed weekly or biweekly results in considerably decreased mean interval concentrations (approximately 25-40% reduction). While most apheresis systems (heparin-induced extracorporeal LDL precipitation, direct adsorption of lipoproteins, lipoprotein apheresis with dextran-sulfate, lipid filtration, immunoadsorption) decrease LDL and Lp(a), Lipopac is specific and only decreases Lp(a). Lp(a) apheresis is expensive and time consuming, but associated with very few side effects. Two randomized controlled trials give conflicting consults with respect to the effect on angiographic changes. Retrospective analyses indicate that regular apheresis translates into clinical benefit in patients with elevated Lp(a), but adequate randomized controlled trials are lacking.

Effects of Lipoprotein apheresis on the Lipoprotein(a) levels in the long run

BACKGROUND

Lipoprotein(a) (Lp(a)) is a low density lipoprotein-like particle to which apolipoprotein(a) is bound. It is recognized as an atherosclerosis-inducing risk factor. Up to now a detailed description of the effect of Lipoprotein apheresis (LA) on Lp(a) levels in the long run is lacking.

METHODS

We studied 59 patients with elevated Lp(a) levels who were treated with LA at the Lipoprotein Apheresis Center at the University Hospital Dresden. We analyzed Lp(a) concentrations before the start of the LA treatment and during this extracorporeal therapy.

RESULTS

Comparing the Lp(a) levels before the start of LA therapy and pre-apheresis (measured before the LA sessions) Lp(a) levels, we observed a reduction of the Lp(a) levels of about 22.8% in all patients. Lp(a) levels were acutely (comparing post-apheresis with pre-apheresis concentrations) reduced by all 6 available LA methods (by about 70%). A linear regression analysis was performed to differentiate the long term course of pre-apheresis Lp(a) levels. In 30 patients we saw an increase of the pre-apheresis Lp(a) levels over the time, in 15 patients a constancy and in 14 patients a decrease. Patients with a decrease of pre-apheresis Lp(a) levels over the time had significantly higher initial (before the start of the extracorporeal treatment) and pre-apheresis values and they were significantly older. These patients had significantly more severe peripheral arterial disease as well as cardiac valve and carotid stenosis. The patients with the lowest initial Lp(a) levels and an increase of the pre-apheresis Lp(a) levels over the time had the highest percentage of intake of Tredaptive(®)/Niaspan(®) though after stopping the intake of these nicotinic acid preparations no clear increase of Lp(a) concentrations was observed. The applied LA systems did not seem to have a significant influence on the course of pre-apheresis Lp(a) levels. In all patients there was a high variability of Lp(a) concentrations between LA sessions which may in part be due to the inaccuracy of the method used to measure Lp(a) concentrations.

CONCLUSION

Pre-apheresis Lp(a) levels (before the LA sessions) are lower than those before the start of a LA treatment but they behave differently among patients during LA treatment.

Impact of LDL apheresis on atheroprotective reverse cholesterol transport pathway in familial hypercholesterolemia

In familial hypercholesterolemia (FH), low HDL cholesterol (HDL-C) levels are associated with functional alterations of HDL particles that reduce their capacity to mediate the reverse cholesterol transport (RCT) pathway. The objective of this study was to evaluate the consequences of LDL apheresis on the efficacy of the RCT pathway in FH patients. LDL apheresis markedly reduced abnormal accelerated cholesteryl ester transfer protein (CETP)-mediated cholesteryl ester (CE) transfer from HDL to LDL, thus reducing their CE content. Equally, we observed a major decrease (-53%; P < 0.0001) in pre-β1-HDL levels. The capacity of whole plasma to mediate free cholesterol efflux from human macrophages was reduced (-15%; P < 0.02) following LDL apheresis. Such reduction resulted from a marked decrease in the ABCA1-dependent efflux (-71%; P < 0.0001) in the scavenger receptor class B type I-dependent efflux (-21%; P < 0.0001) and in the ABCG1-dependent pathway (-15%; P < 0.04). However, HDL particles isolated from FH patients before and after LDL apheresis displayed a similar capacity to mediate cellular free cholesterol efflux or to deliver CE to hepatic cells. We demonstrate that rapid removal of circulating lipoprotein particles by LDL apheresis transitorily reduces RCT. However, LDL apheresis is without impact on the intrinsic ability of HDL particles to promote either cellular free cholesterol efflux from macrophages or to deliver CE to hepatic cells.

Low-density lipoprotein apheresis: principles and indications

Low-density lipoprotein (LDL) apheresis describes a group of apheresis techniques that selectively remove apolipoprotein B-containing lipoproteins producing an acute reduction in LDL-cholesterol (LDL-C). Six devices are available for the removal of LDL-C while sparing other important plasma components. The LDL-apheresis (LDL-A) is not routinely used for the treatment of hypercholesterolemia, which usually responds to medical management, but is used to treat familial hypercholesterolemia, an inherited metabolic abnormality resulting in premature death due to progressive coronary artery disease, and to treat patients who fail medical management. The mechanism of action of the available LDL-A devices, reactions that can occur with these treatments, and the role of this specialized apheresis technique in the treatment of hypercholesterolemia are described.

LDL-apheresis depletes apoE-HDL and pre-β1-HDL in familial hypercholesterolemia: relevance to atheroprotection

Subnormal HDL-cholesterol (HDL-C) and apolipoprotein (apo)AI levels are characteristic of familial hypercholesterolemia (FH), reflecting perturbed intravascular metabolism with compositional anomalies in HDL particles, including apoE enrichment. Does LDL-apheresis, which reduces HDL-cholesterol, apoAI, and apoE by adsorption, induce selective changes in HDL subpopulations, with relevance to atheroprotection? Five HDL subpopulations were fractionated from pre- and post-LDL-apheresis plasmas of normotriglyceridemic FH subjects (n = 11) on regular LDL-apheresis (>2 years). Apheresis lowered both plasma apoE (-62%) and apoAI (-16%) levels, with preferential, genotype-independent reduction in apoE. The mass ratio of HDL2:HDL3 was lowered from ~1:1 to 0.72:1 by apheresis, reflecting selective removal of HDL2 mass (80% of total HDL adsorbed). Pre-LDL-apheresis, HDL2 subpopulations were markedly enriched in apoE, consistent with ~1 copy of apoE per 4 HDL particles. Large amounts (50-66%) of apoE-HDL were removed by apheresis, preferentially in the HDL2b subfraction (-50%); minor absolute amounts of apoE-HDL were removed from HDL3 subfractions. Furthermore, pre-β1-HDL particle levels were subnormal following removal (-53%) upon apheresis, suggesting that cellular cholesterol efflux may be defective in the immediate postapheresis period. In LDL-receptor (LDL-R) deficiency, LDL-apheresis may enhance flux through the reverse cholesterol transport pathway and equally attenuate potential biglycan-mediated deposition of apoE-HDL in the arterial matrix.

Successful treatment of homozygous familial hypercholesterolemia using cascade filtration plasmapheresis

OBJECTIVE

The aim of this study was to report the efficacy of low-density lipoprotein cholesterol (LDL-C) apheresisusing a cascade filtration system in pediatric patients with homozygous familial hypercholesterolemia (FH), and toclarify the associated adverse effects and difficulties.

MATERIAL AND METHODS

LDL-C apheresis using a cascade filtration system was performed in 3 pediatric patientswith homozygous FH; in total, 120 apheresis sessions were performed.

RESULTS

Cascade filtration therapy significantly reduced the mean LDL-C values from 418 ± 62 mg/dL to 145 ± 43 mg/dL (p= 0.011). We observed an acute mean reduction in the plasma level of total cholesterol (57.9%), LDL-C (70.8%),and high-density lipoprotein cholesterol (HDL-C) (40.7%). Treatments were well tolerated. The most frequent clinicaladverse effects were hypotension in 3 sessions (2.5%), chills (1.7%) in 2 sessions, and nausea/vomiting in 3 sessions(2.5%).

CONCLUSION

Our experience using the cascade filtration system with 3 patients included good clinical outcomes andlaboratory findings, safe usage, and minor adverse effects and technical problems.

CONFLICT OF INTEREST

None declared.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Protein adsorption during LDL-apheresis: proteomic analysis

BACKGROUND

The aim of our study was to investigate the clearance of functional proteins by different low-density lipoprotein-apheresis (LDL-A) methods with the help of proteomic analyses.

METHODS

Proteins were eluated from the different LDL-A columns and investigated with 2D electrophoresis combined with mass spectrometry methods. In parallel, we quantified the plasma protein loss from patients treated with double-filtration plasmapheresis (DFPP; n = 9), direct adsorption of lipoproteins (DALI; n = 5) or heparin-induced extracorporeal LDL precipitation (HELP; n = 7) with routine laboratory methods and western blots.

RESULTS

Proteomic analyses of the column-bound proteins revealed a column-type-dependent loss with the highest number of protein spots in DALI-treated patients (1001 +/- 36), followed by HELP (881 +/- 25) and DFPP (535 +/- 20). More than 70 functional proteins were identified. These proteins are involved in the coagulation pathway (e.g. kininogen1) and have adhesive (e.g. fibronectin), rheological (e.g. fibrinogen) and immunological/inflammatory properties (e.g. complement components). Quantification with western blot analyses demonstrated a significant depletion (P < 0.01) of these proteins comparing serum samples before and after the column with a systemic lowering in patients' serum.

CONCLUSIONS

These data reveal strong interaction between column and serum proteins during LDL-A. The clearance of proteins with adhesive, rheological, and inflammatory characteristics may have beneficial effects on microcirculation and reduce chronic inflammation but may also concomitantly induce side effects such as an increased bleeding risk.

Apheresis in Coronary Heart Disease With Elevated Lp (a): A Review of Lp (a) As a Risk Factor and Its Management

Lipoprotein (a) (Lp (a)) increases global cardiovascular risk, especially when LDL cholesterol is concomitantly elevated. Epidemiologic data show that Lp (a) concentration in plasma can be used to predict the risk of early atherogenesis in a dose-dependent manner and late stages of atherosclerosis are accelerated by elevated Lp (a). Therapeutic means to lower Lp (a) are limited. The most effective method to reduce plasma Lp (a) concentration significantly is therapeutic apheresis. Because apheresis is laborious and expensive, patients considered for this procedure should suffer from high Lp (a) concentrations, well beyond 50 mg/dL, and have manifested and progressive coronary heart disease despite maximal drug therapy. Experimental data and therapeutic results will be discussed in the present paper.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.

Comparative analysis of efficiency and specificity of various sorbents for apheresis of low-density lipoproteins

Efficiency of sorbents for LDL apheresis was compared in vitro. The sorbents based on ion-exchange interaction of the ligand with LDL (Liposorber, DALI) exhibited minimum specificity towards the eliminated component, while immunosorbents (LNP-Lipopak, LDR-TheraSorb) were most efficient. By sorption capacity, the available hemosorbents are inferior to plasmasorbents, which explains low efficiency of the therapy based on single application of hemosorbents especially in patients with consederably increased content of LDL cholesterol.

Hypercholesterolemia and LDL apheresis

Several trials have assessed the link between low-density lipoprotein cholesterol (LDL) and the development of coronary heart disease (CHD). LDL apheresis provides an effective role in treating patients with familial hypercholesterolemia (FH) and in preventing the progression of coronary artery disease (CAD). Five different techniques of LDL apheresis are in current use: immunoadsorption (IMA), dextran sulphate-cellulose adsorption (DSA), heparin extracorporeal LDL precipitation system (HELP), double filtration plasmapheresis (DFPP) or lipidfiltration and direct adsorption of lipoprotein using hemoperfusion (DALI). All methods are efficient,but their cost restricts LDL apheresis to the treatment of FH. Indications could include other diseases, but controlled trials are still lacking.

Lipidfiltration--safe and effective methodology to perform lipid-apheresis

Familial hypercholesterolemia (FH) not adequately responding to diet and drug therapy represents an indication for extracorporeal lipid-apheresis, which has become an highly effective and approved therapy for those patients in several countries. Based on different methodology, five treatment options of lipid-apheresis exist and are in widespread practical use covered by regular reimbursement in Germany. All methods are safe and demonstrate equivalent efficacy of reducing LDL cholesterol with respect to the single apheresis session as well as during long-term treatment. Therefore German reimbursement guidelines leave the choice of the method to the discretion of the apheresis center. Related to properties of the used technology all methods exhibit characteristic patterns of additional plasma protein elimination, which do not impair, but in part may increase the therapeutic benefit of lipid-apheresis. Fibrinogen reduction has to be mentioned as an example. The Lipidfiltration system is based on plasmafiltration previously referred to as membrane differential filtration (MDF), synonymous with double filtration plasmapheresis (DFPP). The new term Lipidfiltration was the result of technological progress in the manufacturing process of the plasmafilter resulting in enhanced sieving characteristics and capacity. The Lipidfiltration system is completed by a specifically designed therapy machine with optimised performance characteristics.

Effects of ezetimibe on plasma lipoproteins in severely hypercholesterolemic patients treated with regular LDL-apheresis and statins

Ezetimibe, a cholesterol absorption inhibitor, can be combined with statins to lower LDL-cholesterol. We evaluated additional ezetimibe (10 mg/day) in a placebo-controlled, double blind, randomized cross-over study in 20 patients (age 56+/-9 years, m:f 10:10, BMI 27.5+/-4.0 kg/m(2)) suffering from severe hypercholesterolemia and CHD who were treated by statins and regular LDL-apheresis. Lipoproteins (cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, VLDL-cholesterol, VLDL-triglycerides, lipoprotein(a)) were determined twice (before and during ezetimibe/placebo, each given for 5 weeks), dietary behaviour was analyzed once (3-days-protocol) during each treatment period. During ezetimibe the mean (+/-S.D.) preapheresis LDL-cholesterol concentration decreased from 159+/-26 mg/dl (4.11+/-0.67 mmol/l) to 133+/-28 mg/dl (3.44+/-0.72 mmol/l) (-16+/-11%, P<0.0001, Wilcoxon test) and the postapheresis LDL-cholesterol from 51+/-9 mg/dl (1.32+/-0.23 mmol/l) to 43+/-8 mg/dl (1.11+/-0.21 mmol/l) (-14+/-25%, P<0.05), while there was no significant change during placebo. Mean VLDL-cholesterol fell by 18+/-71% (P<0.05) during ezetimibe and was not significantly changed by placebo (+19+/-70%). Furthermore, during ezetimibe less plasma volume was treated (3725+/-1560 versus 3870+/-1549 ml, P<0.05). Ezetimibe had no effect on pre- and postapheresis triglyceride, HDL-cholesterol and lipoprotein(a) levels. The effect of ezetimibe was independent of the statin dose. Dietary behaviour did not change and no side effects were observed. Thus, in patients with severe LDL-hypercholesterolemia and CHD the addition of ezetimibe to intensive lipid lowering therapy (statins and LDL-apheresis) resulted in a further, clinically significant decrease of LDL-cholesterol.

Achieving lipid goals in Europe: how large is the treatment gap?

Despite the established benefits of decreasing low-density lipoprotein cholesterol levels in reducing morbidity and mortality from coronary heart disease, not all patients who would benefit from lipid-lowering therapy are being managed appropriately. An in-depth review of the literature (2000-2003) demonstrates that the 'treatment gap' varies across different clinical settings. Although the use of lipid-lowering agents has increased in recent years, there continues to be a widespread failure in the achievement of recommended lipid levels. A combination of the use of the most efficacious statins, together with intervention strategies to ensure that all eligible individuals receive appropriate treatment to achieve lipid goals, are important considerations in minimizing the burden of dyslipidemia in Europe.

Current management of severe homozygous hypercholesterolaemias

PURPOSE OF REVIEW

This review focuses on recent advances in the management of patients with homozygous familial hypercholesterolaemia, autosomal recessive hypercholesterolaemia and familial defective apolipoprotein B.

RECENT FINDINGS

Autosomal recessive hypercholesterolaemia has been described as a 'phenocopy' of homozygous familial hypercholesterolaemia. Although the clinical phenotypes are similar, autosomal recessive hypercholesterolaemia seems to be less severe, more variable within a single family, and more responsive to lipid-lowering drug therapy. The cardiovascular complications of premature atherosclerosis are delayed in some individuals and involvement of the aortic root and valve is less common than in homozygous familial hypercholesterolaemia. Apheresis is still the treatment of choice in homozygous familial hypercholesterolaemia and in autosomal recessive hypercholesterolaemia patients in whom maximal drug therapy does not achieve adequate control. In addition to the profound cholesterol-lowering effects of apheresis, other potentially beneficial phenomena have been documented: improved vascular endothelial function and haemorheology, reduction in lipoprotein (a) and procoagulatory status, and a decrease in adhesion molecules and C-reactive protein.

SUMMARY

Patients with severe homozygous hypercholesterolaemia illustrate the natural history of atherosclerosis within a condensed timeframe. Effective cholesterol-lowering treatment started in early childhood is essential to prevent onset of life-threatening atherosclerotic involvement of the aortic root and valve, and the coronary arteries. Noninvasive methods for regular monitoring of the major sites involved in the atherosclerotic process are necessary in patients with no symptoms or signs of ischaemia. Management of patients with severe homozygous hypercholesterolaemia continues to be a major challenge.

Efficacy and Safety of a New Whole-blood Low-density Lipoprotein Apheresis System (Liposorber D) in Severe Hypercholesterolemia

Low-density lipoprotein (LDL) apheresis is an extracorporeal modality to lower LDL cholesterol. While most of the devices eliminate LDL particles from plasma, a recently introduced whole-blood perfusion column (DALI) adsorbs lipoproteins directly from whole blood. We investigated the efficacy and safety of a new whole-blood LDL apheresis system (Liposorber D) in 10 patients with severe hypercholesterolemia in a multicenter trial. In 93 LDL aphereses, the mean reduction in LDL cholesterol and lipoprotein(a) was 62.2 +/- 11.5% and 55.6 +/- 16.9%, respectively (P < 0.01). If hemodilution during apheresis was considered, the reductions were 58.0 +/- 10.9 and 55.3 +/- 10.9%, respectively (P < 0.01), while high-density lipoprotein (HDL) cholesterol did not change significantly. Three mild episodes of hypocalcemia and two mild episodes of arterial hypotension were observed; however, LDL apheresis could be continued in each case. In conclusion, the new whole-blood LDL apheresis with Liposorber D is a safe, simple, and useful modality to reduce LDL cholesterol and lipoprotein(a) in cardiovascular high-risk patients.

From membrane differential filtration to lipidfiltration: technological progress in low-density lipoprotein apheresis

Extracorporeal low-density lipoprotein (LDL) apheresis is an established and highly effective therapy for patients with familial hypercholesterolemia (FH) not adequately responding to diet and drug therapy alone. Based on different methodology, five treatment options of LDL apheresis are available and in widespread practical use in Germany. All methods are safe and demonstrate equivalent efficacy of reducing LDL cholesterol with respect to the single apheresis session as well as during long-term treatment. Owing to methodological properties all methods also exhibit characteristics of additional plasma protein elimination, which do not impair, but in part, increase the beneficial therapeutic effect of LDL apheresis. Fibrinogen reduction has to be mentioned as an example. The lipidfiltration system is based on plasmafiltration previously named membrane differential filtration (MDF), synonymous with double filtration plasmapheresis (DFPP). The new term lipidfiltration was the result of technological progress leading to a significant improvement of the efficiency. The system consists of a novel lipid filter with enhanced sieving characteristics and capacity, and is completed by an enhanced therapy machine with an optimized heating unit.

Extracorporal low-density lipoprotein elimination by immunoadsorption

Low-density lipoprotein (LDL) apheresis has proven its therapeutic usefulness in patients who suffer from coronary heart disease but cannot achieve LDL cholesterol concentrations defined by the National Cholesterol Education Program guidelines. Immunoadsorption was the first commercially available apheresis technique. It is based on affinity chromatography. As with other apheresis techniques, immunoadsorption has specific advantages and disadvantages. These have to be taken into account when selecting an apheresis technique for the individual patient.

Differential indication of lipoprotein apheresis during pregnancy

Lipoprotein apheresis is an effective treatment for severe disorders of lipid metabolism. It is the only life prolonging therapy for patients with homozygous familial hypercholesterolemia. Changes of lipid metabolism during pregnancy related to changes of hormone concentrations do not cause clinical complications in the majority of cases. However, in particular clinical situations there is the need to offer a therapeutic option. Increasing morbidity and mortality of mother and child due to severe disorders of lipid metabolism have to be prevented. In general, lipid lowering drugs are contraindicated during pregnancy. Therefore, lipoprotein apheresis offers an alternative, which could be used in select cases to treat acute or chronic hyperlipoproteinemia associated with pregnancy. This article summarizes experiences with patients, who became pregnant during chronic lipoprotein apheresis, or who were treated by lipoprotein apheresis because of acute disorders of lipid metabolism during pregnancy. In conclusion, after individual risk benefit analysis for mother and child lipoprotein apheresis can be safely performed during pregnancy.

LDL apheresis

Low density lipoprotein (LDL) apheresis provides a safe and effective means of treating patients with homozygous familial hypercholesterolaemia (FH). It also has a role in preventing the progression of coronary artery disease in heterozygotes and others with severe dyslipidaemia who are refractory to or intolerant of high doses of lipid-lowering drugs. Established methods involve either adsorption of apolipoprotein B-containing lipoproteins by affinity columns containing anti-apolipoprotein B antibodies or dextran sulphate, or their precipitation at low pH by heparin, in each instance after first separating plasma from blood cells with a cell separator. The most recently developed method enables lipoproteins to be adsorbed directly from whole blood, using polyacrylate columns. All 4 methods have proved to be similarly efficient when used weekly or biweekly to lower LDL cholesterol and Lp(a) without unduly reducing HDL cholesterol. Economic constraints restrict the use of LDL apheresis to the treatment of potentially fatal disorders such as FH, where there is clear evidence of benefit compared with conventional therapy. Widening the indications to include the treatment of other dyslipidaemic disorders such as steroid-resistant nephrotic syndrome, post-transplant donor vessel disease, stroke and prevention of re-stenosis after coronary angioplasty requires evidence from controlled trials that is currently lacking.

Intraindividual comparison of two extracorporeal LDL apheresis methods: lipidfiltration and HELP

Low density lipoprotein (LDL) apheresis is an effective treatment option for patients with severe hypercholesterolemia not adequately responding to diet and drug therapy. Membrane differential filtration (MDF), synonymous with double filtration plasmapheresis (DFPP), here named Lipidfiltration, and heparin-induced extracorporeal LDL-precipitation (HELP) are two of the five methods available for extracorporeal LDL apheresis. In this prospective investigation 6 patients with severe LDL-hypercholesterolemia and CAD were treated in a cross-over design with Lipidfiltration at two stages of technical development and HELP to compare the efficacy of these two LDL apheresis methods with respect to lowering and modifying plasma lipids and rheologically relevant plasma proteins, especially fibrinogen. In total, 44 LDL apheresis sessions were investigated. In weekly intervals, patients were treated with consecutive LDL apheresis sessions with either Lipidfiltration and HELP, treating identical plasma volumes. In one part of the investigation Lipidfiltration was performed with the novel Lipidfilter EC-50, combined with a newly developed blood and plasma therapy machine allowing optimized plasma heating. The results showed that the reduction rates of LDL-cholesterol, lipoprotein(a) and triglycerides were essentially identical for both methods. Also pretreatment levels of total cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol were not significantly different in both treatment groups. Both methods lead to a significant reduction of serum lipoproteins, especially for LDL-cholesterol, which was decreased by 61.4% with Lipidfiltration (treated plasma volume: 2998 ml) and 61.3% with HELP (treated plasma volume: 3013 ml). With respect to Lipidfiltration LDL-cholesterol reduction was more efficient with the novel Lipidfilter EC-50. Mean pretreatment HDL cholesterol concentrations remained unchanged. Comparing Cascadeflo AC-1770 with the novel Lipidfilter EC-50 reduction rates of HDL-cholesterol (17.4% versus 6.4%) and total protein (17.9% versus 7.8%) were significantly reduced. Lipidfiltration and HELP both resulted in a reduction of plasma viscosity and hemorheologically relevant plasma proteins, like fibrinogen.

Separation of IgG and IgM from albumin in citrated human plasma using electrodialysis and metal ion affinity precipitation

Plasmapheresis is the process by which plasma is separated from whole blood for therapeutic purposes. The primary reason to perform plasmapheresis is to remove immunoglobulins and not to necessarily remove the remainder of the plasma proteins. Nevertheless, most plasmapheresis is performed by centrifugal separation to remove bulk plasma. We have investigated whether electrodialysis and metal ion affinity precipitation can be used to selectively remove immunoglobulins from citrated plasma and potentially serve as an adjunctive technique to centrifugal plasmapheresis. Using a commercial electrodialysis device, we have desalted citrated plasma to separate immunoglobulins from albumin, and have determined the effects of pH adjustment and addition of zinc acetate for concomitant metal ion affinity precipitation. With desalted pH adjusted citrated plasma containing 1.5 mM zinc acetate, we achieved more than 80% recovery of albumin with removal of almost 60% of the immunoglobulin (Ig)G. Almost 80% of polyclonal IgM and 90% of monoclonal IgM was also removed. IgA was not effectively removed under any of the conditions tested. Selective precipitation with electrodialysis and zinc acetate precipitation appears to be an effective technique for the separation of IgG and IgM from albumin in citrated plasma.

Marked removal of bezafibrate-induced high-density lipoprotein-cholesterol by low-density lipoprotein apheresis

BACKGROUND

A case of marked reduction of the bezafibrate-induced increase of high-density lipoprotein (HDL)-cholesterol by low-density lipoprotein apheresis (LDL-apheresis) has not been previously reported.

METHODS

A 68-year-old Japanese man with arteriosclerosis obliterans (ASO), diabetes mellitus, and hyperlipidemia underwent LDL-apheresis, followed by the concomitant bezafibrate administration. Plasma lipids of pre- and post-LDL-apheresis were measured and apolipoprotein E (apoE) localization of the pre- and post-LDL-apheresis was detected by agarose gel electrophoresis.

RESULTS

Plasma concentrations of the total cholesterol, LDL-cholesterol, triglyceride, and HDL-cholesterol of pre-LDL-apheresis were 4.78 +/- 0.36, 2.74 +/- 0.24, 2.44 +/- 0.52, and 0.92 +/- 0.10 mmol/l, respectively; those of the post-LDL-apheresis were 1.94 +/- 0.31, 0.72 +/- 0.13, 0.81 +/- 0.38, and 0.86 +/- 0.11 mmol/l, respectively. LDL-apheresis reduced HDL-cholesterol by 6.4% (p=0.346). During the bezafibrate administration, plasma concentrations of the above of pre-LDL-apheresis were 5.24 +/- 0.34, 3.28 +/- 0.22, 1.26 +/- 0.25, and 1.39 +/- 0.21 mmol/l, respectively; those of the post-LDL-apheresis were 2.25 +/- 0.44, 0.80 +/- 0.12, 0.58 +/- 0.19, and 1.18 +/- 0.16 mmol/l, respectively. LDL-apheresis reduced HDL-cholesterol by 15.2% (p<0.01). Plasma apolipoprotein E detected between the prebeta- and alpha-mobility was markedly lower after the LDL-apheresis in the agarose gel electrophoresis.

CONCLUSIONS

The removal of the bezafibrate induced an increase of the HDL-cholesterol by LDL-apheresis.