LDL Hemoperfusion-A New Procedure for LDL Apheresis: First Clinical Application of an LDL Adsorber Compatible with Human Whole Blood

Abstract: To date, lipid apheresis procedures can remove low-density lipoprotein (LDL) cholesterol (LDL-C) only from plasma. Thus, initially plasma has to be separated from the blood cells, which increases the costs and complexity of the extracorporeal circuit. This paper describes the first clinical application of a new LDL adsorber that eliminates LDL directly from whole blood. The goal of this pilot study was to test the efficacy, safety, and feasibility of direct lipoprotein adsorption in patients. In a 2 center Phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation consisted of an initial heparin bolus followed by an acid citrate dextrose (ACD)-A infusion during the treatment. The processing of nearly 1 patient blood volume resulted in a reduction of LDL-C by 45 ± 8% and triglycerides by 23 ± 20%. HDL-C, fibrinogen, and cell counts were not significantly influenced. In a subgroup of 5 patients who exhibited elevated lipoprotein (a) (Lp[a]) levels, Lp(a) reduction was 43 ± 15% (all results corrected for plasma volume shifts). The sessions were clinically uneventful; the system was technically safe and easily handled. In conclusion, short-term LDL hemoperfusion by the DALI proved to be a safe, effective, and simple procedure for the treatment of patients suffering from symptomatic recalcitrant hypercholesterolemia. The present study represents a solid basis for the clinical long-term evaluation of this new technique in the future.     

Lipid Apheresis by Hemoperfusion: In Vitro Efficacy and Ex Vivo Biocompatibility of a New Low-Density Lipoprotein Adsorber Compatible with Human Whole Blood

Abstract: To date, selective extracorporeal low-density lipoprotein (LDL) removal can only be performed from plasma; that is, a plasma-cell separation step using a centrifuge or a plasma membrane separator is necessary initially. This article characterizes a new polyacrylate-based LDL adsorber directly applicable to whole blood . In vitro single-pass hemoperfusion tests using pooled donor blood showed quantitative adsorption of atherogenic LDL-cholesterol (LDL-C) and complete recovery of protective high-density lipoprotein C. Fibrinogen, another independent risk factor of atherosclerosis, was also adsorbed to a lesser extent. Single-pass ex vivo biocompatibility using fresh donor blood on-line was excellent and resulted in minimal cell loss. Neither signs of hemolysis nor activation of monocytes (interleukin-l production) were detected. Only slight activation of leukocytes (elastase release) and thrombocytes (platelet factor 4 secretion) as well as of coagulation (thrombin-antithrombin complex formation) and complement (C3a, C5a generation) was observed. Under the experimental conditions used, the optimal anticoagulation regimen was 0.5 IU heparin plus 0.375 mg citratelml blood. Priming the column with a buffer of pH 7.4 containing heparin, citrate, and Ca²⁺ is recommended. In conclusion, this new adsorber exhibited selective LDLC adsorption in vitro combined with excellent ex vivo biocompatibility and thus holds great promise for a successful clinical application in a closed-loop system in patients.     

Low–Density Lipoprotein Hemoperfusion Using a Modified Polyacrylate Adsorber: In Vitro, Ex Vivo, and First Clinical Results

Abstract: Current lipid apheresis techniques can remove low–density lipoprotein (LDL) cholesterol only from plasma, i.e., a primary cell–plasma separation step is mandatory. This article describes in vitro, ex vivo, and clinical results using a new LDL adsorber compatible with human whole blood. It consists of modified polyacrylate, the negative charges of which can interact with the positively charged protein B moiety of LDL, thus retaining these particles on the surface of the adsorber. After the efficacy and selectivity of LDL removal had been demonstrated in vitro and ex vivo, a clinical pilot study corroborated these results. Thus, treating 60 ml of blood per kilogram of body weight in a single session, LDL hemoperfusion reduced LDL cholesterol by 50%, lipoprotein (a) by 17%, and triglycerides by 19% in 6 hy–percholesterolemic patients. High–density lipoprotein cholesterol recovery amounted to 97%. In conclusion, LDL hemoperfusion holds great promise for the future.     

State of the Art of Lipid Apheresis

Abstract: Currently, 5 different lipid apheresis procedures are available for routine clinical treatment of hy–percholesterolemic patients. Unselective plasma exchange is a technically simple extracorporeal circuit, but albumin substitution fluid must be used and there is no high–density lipoprotein (HDL) recovery. Semiselective double filtration with improved size selectivity because of a small–pore secondary filter combines good elimination of low–density lipoprotein (LDL), lipoprotein (a) (Lp[a]), and fibrinogen with adequate HDL recovery; modifications such as thermofiltration, predilution/backflush, or pulsatile flow have been proposed for the improvement of this system. Three highly selective procedures are basedon immunologic or electrostatic interactions: immunoad–sorption using anti–low–density lipoprotein (LDL) antibodies, chemoadsorption onto dextran sulfate, and hep–arin–induced LDL precipitation (HELP) apheresis. The features of each system are discussed critically. Lastly, two new developments, Lp(a) immunoadsorption and LDL hemoperfusion using a polyacrylate LDL adsorber compatible with whole blood, are described     

DALI apheresis in hyperlipidemic patients: biocompatibility, efficacy, and selectivity of direct adsorption of lipoproteins from whole blood

Recently, the first apheresis technique for direct adsorption of low-density lipoprotein (LDL) and lipoprotein(a) [Lp(a)] from whole blood (DALI) was developed that does not require a prior plasma separation. That markedly simplifies the extracorporeal circuit. The aim of the present study was to test the acute biocompatibility, efficacy, and selectivity of DALI apheresis. In a prospective clinical study, 6 hypercholesterolemic patients suffering from angiographically proven atherosclerosis were treated 4 times each by DALI. 1.3 patient blood volumes were treated per session at blood flow rates of 60-80 ml/min using 750 or 1,000 ml of polyacrylate/polyacrylamide adsorber gel. The anticoagulation consisted of an initial heparin bolus followed by a citrate infusion. The sessions were clinically essentially uneventful. Mean corrected reductions of lipoproteins amounted to 65% for LDL-cholesterol, 54% for Lp(a), 28% for triglycerides, 1% for HDL-cholesterol, and 8% for fibrinogen. The selectivity of lipoprotein removal was high. Cell counts remained virtually unchanged and no signs of hemolysis or clotting were detected. Cell activation parameters elastase, beta-thromboglobulin, interleukin-1beta, and IL-6 showed no significant increase. Complement activation was negligible. There was significant, but clinically asymptomatic, bradykinin activation in the adsorber with mean maxima of 12,000 pg/ml in the efferent line at 1,000 ml of treated blood volume. In conclusion, DALI proved to be safe, selective, and efficient for the adsorption of LDL-C and Lp(a), which simplifies substantially the extracorporeal therapy in hypercholesterolemic patients.     

LDL Apheresis: A Novel Technique (LIPOCOLLECT 200)

Therapeutic means to lower Lp(a) are limited. The most effective method to reduce plasma Lp(a) concentration significantly is therapeutic apheresis, namely, low‐density lipoprotein (LDL) lipoprotein(a) (Lp(a)) apheresis. A novel technique based on reusable LDL adsorber called Lipocollect 200 (Medicollect, Rimbach, Germany) allows the removal of both LDL and Lp(a) from plasma. Two male patients with hyperLp(a)lipoproteinemia and angiographically established progressive coronary heart disease, without rough elevation of LDL‐cholesterol, who did not respond to diet and medication were submitted to 50 LDL Lp(a) aphereses with Lipocollect 200 LDL Lp(a)‐adsorber at weekly and biweekly intervals. Total cholesterol and LDL cholesterol plasma levels fell significantly by 48.3% (±6.7) to 61.6% (±12.7) (first patient), and 42.5% (±6.3) to 60.6% (±14.3) (second patient), respectively (all differences: P ≤ 0.001). High‐density lipoprotein (HDL)‐cholesterol concentration in plasma did not show statistically significant change. Plasma triglycerides were also significantly reduced by 43.6% (±24.4) (first patient) and 42.3% (±13) (second patient) (both differences: P ≤ 0.001). Plasma Lp(a) showed a statistically significant percent reduction in plasma as expected: 64.7 ± 9.5 (first patient), and 59.1 ± 6.7 (second patient) (both differences: P ≤ 0.001). Plasma fibrinogen concentration was decreased by 35.9% (±18.7) (P ≤ 0.05) (first patient) and 41.8% (±11.5) (second patient) (P ≤ 0.005). Considering the reduction rate between the first and the last procedures, we have compared the mean percent reduction of the first five treatments (from session #1 to #5) with the last five treatments (from session #21 to #25). We have observed an increasing reduction of all activity parameters on both patients apart from HDL‐cholesterol (first patient) and triglyceride (second patient) that showed a decreasing reduction rate. Both patients followed the prescribed schedule and completed the study. Clinically, all sessions were well tolerated and undesired reactions were not reported. The Lipocollect 200 adsorber proved to have a good biocompatibility. In this study, the adsorber reusability for several sessions was confirmed.     

Modified DALI LDL-apheresis using trisodium citrate anticoagulation plus bicarbonate or lactate-buffered hemofiltration substitution fluids as primers

BACKGROUND: DALI (direct adsorption of lipids) is the first LDL-apheresis technique able to adsorb low-density lipoprotein (LDL) and lipoproteina) directly from whole blood. In the standard procedure, acid citrate dextrose (ACD-A) is used as anticoagulation and the adsorber is rinsed with a specially manufactured priming solution (PS). Using neutral trisodium citrate (TSC) instead of ACD-A might improve the acid-base homeostasis during DALI apheresis; moreover, applying wholesale hemofiltration solutions instead of the special PS might avoid the use of two separate solutions for both priming before and reinfusion after the treatment, thus simplifiying the procedure. AIM: The present study was performed to test the effect of neutral (TSC) anticoagulation and of two different commercially available hemofiltration (HF) priming solutions on the efficacy and biocompatibility of DALI apheresis. MATERIALS AND METHODS: Five hypercholesterolemic chronic DALI patients were treated prospectively, on a weekly or biweekly basis, 3 times each by standard DALI-apheresis (A). by DALI using 4% TSC and bicarbonate-buffered HF BIC35-210 priming (B). as well as by DALI using 4% TSC and lactate-buffered HF 23 priming (C). After the sessions, the extracorporeal circuit (ECC) was rinsed with saline in study arm A and with the corresponding HF solutions in study arms B and C, respectively. RESULTS: Acute LDL-cholesterol reductions in the study arms A/B/C averaged 64/64/63%, for Lp(a) 62/64/62%, respectively (n=15). Clinically, all sessions were essentially uneventful and no clots were observed in the ECC. No major differences were found between the 3 study arms with respect to biocompatibility (elastase, C3a, thrombin-antithrombin, beta-thromboglobulin, bradykinin). CONCLUSION: DALI apheresis using TSC anticoagulation and HF solutions for both priming and reinfusion proved to be as safe and effective as the standard DALI apheresis. These modifications, however, further simplify the procedure.     

Low–Density Lipoprotein Adsorption for Arteriosclerotic Patients

Abstract: A wide variety of treatments is now available for arteriosclerosis obliterans (ASO) patients, not very successful in some cases. Low—density lipoprotein (LDL) apheresis using an extracorporeal adsorption column containing dextran sulfate cellulose beads was applied to control lipid levels intensively in ASO patients with accompanying drug—resistant hyperlipidemia. A series of the apheresis procedures had a remarkable impact on clinical symptoms and physiological findings with improvement in intermittent claudication observed in more than 80% of the patients. Improvements in plethysmogram and thermogram readings suggested an increased circulation in lower extremities in more than 80% of patients. In addition, the treatment improved blood rheology, as evidenced by a reduction in blood viscosity. In a follow—up study made by sending a questionnaire to previously treated patients, it was revealed that improvements in clinical symptoms were well maintained even after cessation of the treatment. In conclusion, LDL apheresis proved to be a useful therapeutic tool in ASO patients having elevated lipid levels     

LDL Apheresis in a Homozygous Familial Hypercholesterolemic Child Aged 4.5

Abstract: Preliminary experience with the efficacy and safety of dextran sulfate cellulose low-density lipoprotein (LDL) apheresis for the treatment of a 4.5-year-old girl with homozygous familial hypercholesterolemia and coronary artery disease is reported. The decrease of the most atherogenic apolipoprotein B-containing lipoproteins, low-density lipoprotein (LDL) and lipoprotein(a) (Lp [a]), were in the ranges of 63.1–68.7%, and 52.5–58.6%, respectively. The child tolerated LDL apheresis without any clinically significant complications. Therefore, she was submitted to a long-term program of treatment at intervals of 15 days. The experience suggests the possibility of an early beginning of extracorporeal treatment with LDL apheresis in children severely affected by homozygous or double heterozygous familial hypercholesterolemia.     

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.     

Effect of low-dose citrate anticoagulation on the clinical safety and efficacy of direct adsorption of lipoproteins (DALI apheresis) in hypercholesterolemic patients: a prospective controlled clinical trial

Direct adsorption of lipoproteins (DALI) is the first lipid apheresis system compatible with whole blood with the advantage of a very simple procedure. A mixture of heparin plus citrate (ACD-A) is used for the anticoagulation regimen (AR). A clinical, prospective, controlled crossover study was performed to test the safety and efficacy of low-dose citrate (LDC) anticoagulation in DALI. Five chronic DALI patients suffering from coronary heart disease and hypercholesterolemia underwent 3 DALI sessions each using the LDC anticoagulation regimen (60 IU heparin/kg body weight as initial bolus; 1:40 ACD-A: blood as perfusion). This was compared to 3 sessions per patient with the standard AR (bolus of 20 IU heparin/kg, 1:20 ACD-A as perfusion). Patient blood volumes (1.6; average of 7,040 ml) were treated with 750 ml adsorber gel per session at a blood flow rate of 60 ml/min. Mean LDL and Lp(a) reductions exceeded 60% with both AR. No clinical side effects were observed. Both AR controlled the coagulation well as evidenced by a sufficient prolongation of the partial prothrombin time (PTT) and activated clotting time as well as low thrombin-antithrombin (TAT) formation. Biocompatibility parameters exhibited favorable results (low activation of complement and cells, and only slight formation of C3a, C5a, beta-thromboglobulin, elastase, and TNF-alpha). The asymptomatic bradykinin generation was comparable in both study arms. LDC optimized the ionized calcium levels and pH in the efferent blood postadsorber. LDC anticoagulation was safe and effective, and may further improve the tolerance of DALI apheresis in hypercholesterolemic patients.     

Development of Selective Low-Density Lipoprotein (LDL) Apheresis System: Immobilized Polyanion as LDL-Specific Adsorption for LDL Apheresis System

Abstract: Low-density lipoprotein (LDL) is widely recognized as one of the major risk factors for developing coronary heart diseases. Despite intensive development of LDL-lowering drugs, there still exist those patients with refractory hyperlipidemia whose plasma LDL levels are not sufficiently lowered by drugs. LDL apheresis, direct removal of plasma LDL from circulating blood, is thought to be the most promising treatment for such refractory patients. Various techniques, such as the use of an im-munoadsorbent utilizing an anti-LDL antibody, have been used in an attempt to achieve the selective removal of LDL. However, none were widely used because of complications, poor selectivity, and so forth. To establish a safe and effective LDL apheresis system, we chose a synthetic affinity adsorbent as the LDL-removing device. Synthetic polyanion compounds were used as the affinity ligands for LDL adsorbent to simulate the anion-rich sequence of LDL binding sites in the human LDL receptor. Among various polyanion compounds, those polyanions with sulfate or sulfonate groups and hydrophilic backbone were found to have strong affinity for LDL. In contrast, polyanions with carboxyl groups showed poor affinity. Dextran sulfate (DS) was selected as the affinity ligand of LDL adsorbent for its high affinity and low toxicity. The influence of its charge density and molecular weight on its affinity for LDL was suitable. The affinity rapidly increased as the charge density increased, then, reached a constant value. Little affinity was found for either the DS monomer (glucose sulfate) or DS with a molecular weight higher than 10⁴ daltons whereas DS with molecular weights in the midrange showed strong affinity. DS with a midrange molecular weight was immobilized on cellulose hard gel to give LDL adsorbent clinical application. The adsorbent demonstrated an excellent selectivity for LDL and very low density lipoprotein (VLDL) in vitro. Adsorption of high-density lipoprotein and major plasma proteins was almost negligible. Additional study of the LDL-binding mechanism revealed that DS directly interacts with positively charged sites on LDL, which demonstrates that the nature of the interaction is the same as that of LDL receptor. An LDL adsorption column (Liposorber) packed with an LDL adsorbent and polysulfone hollow-fiber plasma separator (Sulflux) was developed as an efficient LDL apheresis system. Clinical investigation proved that this system is capable of intensively lowering the plasma LDL level without affecting major plasma components.     

Lipid Apheresis: From a Heroic Treatment to Routine Clinical Practice

Abstract: Lipid apheresis has developed from a heroic treatment into a routine clinical therapy and currently is the major indication for performing extracorporeal plasma therapy. Whereas it was once reserved for patients with homozygous familial hypercholesterolemia, today it has a place in the secondary prevention of severe coronary heart disease when low-density lipoprotein (LDL)-cholesterol levels exceed 150 mg/dl, despite conservative treatment, in any type of primary hypercholesterolemia. Unselective plasma exchange has been replaced by a variety of selective procedures. The efficacy of the treatment can be maximized by combining LDL apheresis with the use of cholesterol synthesis enzyme inhibitors. Clinical studies have shown that drastic cholesterol reduction can result in regression of coronary atherosclerosis as well as in reduced cardiac morbidity and mortality. Technical progress comprises improved selectivity, online regeneration of adsorbers, and LDL adsorption from whole blood. Recently, a new LDL hemoper-fusion procedure was successfully tested in a clinical pilot study; blood is passed directly over a lipid sorbent without prior plasma separation. If this system is demonstrated to be safe and effective in clinical Phase III trials, a further qualitative step in the rapid development of LDL apheresis will have been made.     

低密度脂蛋白在绝经后骨质疏松中的作用研究进展

随着人口老龄化,骨质疏松发病率逐渐升高,其中绝经后骨质疏松占了非常大的比例,况且骨质疏松不易发现,往往发展成骨折才被察觉,给绝经后妇女的日常生活带来了莫大的困扰.然而其发病机制尚不明确,因此积极探索其发病因素与机制成为亟待解决的问题.近年来随着探索的深入,脂代谢紊乱成为研究绝经后骨质疏松症(postmenopausal...     

Insulin resistance, LDL particle size, and LDL susceptibility to oxidation in pediatric kidney and liver recipients

BACKGROUND: Dyslipidemia is common after solid organ transplantation. We have described hypertriglyceridemia in about 50% of our pediatric kidney, and in about 30% of our liver recipients. The aim of the present study was to find out whether this post-transplantation hypertriglyceridemia after pediatric solid organ transplantation is associated with insulin resistance and the occurrence of small, dense low-density lipoprotein (LDL). METHODS: Fifty kidney and 25 liver recipients (aged 4 to 18 years) on triple immunosuppression, and 181 control children participated in the study for an average of 5.3 and 6.4 years after kidney and liver transplantation (range 1 to 11 years), respectively. Homeostasis model assessments for insulin resistance (HOMA) were calculated and fasting lipoprotein lipid profile, apolipoprotein A-I and B concentrations, LDL particle diameter, and indices of LDL susceptibility to copper-induced oxidation determined. RESULTS: Kidney patients had significantly higher serum total, high-density, and low-density lipoprotein cholesterol, triglyceride, apolipoprotein A-I and B concentrations than liver patients or control subjects (P < 0.003 for all). HOMA indices higher than the 95th percentile of Canadian normal children were seen in 50.0% of kidney (of liver 41.2%) recipients younger than 11 years, and in 27.3% of older recipients (of liver 37.5%). Smaller sized LDL or LDL of increased oxidizability was not more frequent in patients than in control children. CONCLUSION: Pediatric kidney recipients had significantly higher lipid and insulin concentrations than healthy control children. Combined hyperlipidemia and features of the dysmetabolic syndrome were common in children after kidney and liver transplantation. However, no small, dense LDL, or LDL prone to oxidation was seen in either group.     

Long-term efficiency, biocompatibility, and clinical safety of combined simultaneous LDL-apheresis and haemodialysis in patients with hypercholesterolaemia and end-stage renal failure

Three hypercholesterolaemic patients on maintenance haemodialysiswith angiographically proven coronary artery disease were treatedin a once-a-week schedule by combined, synchronous lipid apheresis(using heparin-induced extracorporeal LDL precipitation) andhaemodialysis (HELP/HD) for 65–104 weeks. Clinical side-effectswere few and mostly related to high ultrafiltration rates inpatients with low compliance regarding interdialytic fluid restriction.Biocompatibility of the procedure was shown to be good and bloodcell losses, leukocyte (elastase release) and thrombocyte (ß-thromboglobulinextrusion) as well as complement (C3a formation) activationwere minimal. Interestingly, most of the C3a generated in theextracorporeal HELP circuit was immediately removed again inthe precipitate filter. In the pseudo-steady-state after 3 monthsof regular therapy, acute haematocrit-corrected reduction ofplasma components after the session compared to pre values wereabout 55% for the risk factors LDL cholesterol (LDL-C), lipoprotein(a)(Lp(a)), and fibrinogen (FIB) with good recovery of HDL-C andother proteins. Urea, creatinine, and phosphate eliminationwas similar to normal haemodialysis. Mean interapheresis values of risk factors after one (n=2) andtwo (n=1) years of treatment were crucially dependent upon ultrafiltration(UF); thus, in two patients with high UF LDL-C concentrationsamounting to 185 and 220mg/dl at baseline and were reduced toabout 135mg/dl LDL-C, while in the patient with low UF the reductionwas from 231 mg/dl to 80 mg/dl. The atherogenic index (LDL-C/HDL-C)was reduced from 6.4 and 5.1 to about 4.3 in patients with highUF, from 6.1 to 3.3 in the patient with low UF. Fibrinogen andLp(a) were normalized in all patients. In summary, the combined HELP/HD treatment in hypercholesterolaemicdialysis patients proved to be a safe, effective, and selectiveprocedure for lipoprotein and fibrinogen normalization withexcellent biocompatibility and good clinical patient tolerance,providing a tool ready for future atherosclerosis regressionstudies in ESRD patients.     

Disturbed LDL and scavenger receptor functions in monocytes from chronic haemodialysed patients.

BACKGROUND: The most frequent complication in patients with end-stage renal failure on chronic haemodialysis (HD) treatment is atherosclerosis, i.e. the different forms of heart and vascular diseases. The complete disorder of serum lipid and lipoprotein patterns is well demonstrated, whereas our knowledge about the low-density lipoprotein (LDL) and scavenger receptor expression and function are poorly understood. METHODS: In our current work, LDL and scavenger receptor expression and functions were simultaneously studied in monocytes obtained from 15 healthy male control subjects and from 11 chronic HD male patients applied with (125)I-labelled LDL, isolated from healthy volunteers. To study the scavenger LDL receptors, labelled acetylated LDL (acLDL) was used. RESULTS: LDL binding to the monocytes of the HD-group was found to be decreased in comparison to that of the controls. As a result, the 50 microg LDL protein-induced inhibition of endogenous cholesterol synthesis was also diminished. In contrast, acLDL binding was greatly increased, though it could trigger only a low apoE synthesis. Consequently the number of cholesterol inclusions in monocytes was increased. CONCLUSIONS: The disturbed expression and function of LDL and scavenger receptors both may play significant roles in pathogenesis of cardiovascular complications in chronic HD patients. Based on our present results, it can be assumed that dysfunction of scavenger receptors is at the centre of cardiovascular complications of HD patients with renal failure.     

Short–and Long–Term Effects on Serum Lipoproteins by Three Different Techniques of Apheresis

Abstract: Low–density lipoprotein (LDL) apheresis is applied in patients with coronary heart disease because of severe inherited forms of hypercholesterolemia, for which dietary and combined drug treatment cannot lower LDL cholesterol concentrations less than 130 mg/dl. The following article describes the changes in lipoprotein levels in a total of 19 patients undergoing weekly LDL apheresis. Immunoadsorption, operating with polyclonal antibodies against apolipoprotein B–100, was used in 6 patients. Five patients were put on heparin–induced extracorporeal LDL precipitation (HELP) therapy; 6 received dextran sulfate adsorption treatments. Under steady–state conditions a single treatment reduced LDL cholesterol by 149 ± 3 m/dl with immunoadsorption, 122 ± 2 mg/dl with HELP, and 124 ± 18 mg/dl with dextran sulfate adsorption. Lipoprotein (a) (Lp[a]) declined by 52 to 65%. Very low density lipoprotein (VLDL) cholesterol and VLDL triglycerides declined by 45 to 55% because of the activation of lipoprotein lipase and precipitation during the HELP procedure. In all procedures, there was a small reduction in the different high–density lipoprotein fractions, which had returned to normal after 24 h. The long–term HDL3 cholesterol levels increased significantly. During all procedures there was a decrease in the molar esterification rate of lecithin cholesterol acyltrans–ferase activity. All changes in lipid fractions were paralleled by changes in the corresponding apolipoprotein levels. It is concluded that all three techniques described are powerful tools capable of lowering LDL cholesterol in severe hereditary forms of hypercholesterolemia. In HELP and dextran sulfate adsorption, the amount of plasma is limited by the elimination of other plasma constituents. Immunoadsorption may thus be preferred in very severe forms of hypercholesterolemia.