Comparison of selectivity of LDL removal by double filtration and dextran-sulfate cellulose column plasmapheresis

Removal and Recovery of Cholesterol in Thermofiltration

Thermofiltration, a system of membrane plasmapheresis for LDL apheresis, was applied to the treatment of hypercholesterolemic patients to assess its lipid lowering potential, clinical feasibility and post-treatment lipid recovery.

Plasma separated by a membrane separator was warmed above physiologic temperature, filtered with a plasma filter and returned to the patient on-line without requiring supplemental plasma product infusion. One calculated plasma volume was treated. Treatment schedules were weekly, biweekly or monthly. Patients treated by thermofiltration in this study were diagnosed as type II hypercholesterolemia. Reductions and sievings of high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol were evaluated. In addition, post-treatment solute recovery was assessed.

The reduction ratios of HDL cholesterol and LDL cholesterol were 0.31 ± 0.08 and 0.58 ± 0.08, respectively (mean ± S.D. of 7 patients). Sieving coefficients of the plasma filter for HDL cholesterol and LDL cholesterol were 0.62 ± 0.12 and 0.03 ± 0.02, respectively (mean ± S.D. of 32 treatments). Cholesterol reduction fitted well to a single pool model. HDL cholesterol recovered significantly faster than LDL cholesterol and LDL cholesterol recovery differed among individuals. For some patients total cholesterol and LDL cholesterol levels were lowered by the biweekly treatment while for others the weekly treatment was required. Significant removal of LDL cholesterol with sparing of HDL cholesterol was achieved without the requirement for plasma products.

Hypertriglyceridemia: Apheretic Treatment

Patients with extremely high triglyceride levels and associated lipemia are at high risk for acute pancreatitis. Two factors can increase triglyceride-rich lipoproteins; one is overproduction and other is a defect in clearance. Either mechanism can cause hypertriglyceridemia and both may exist simultaneously. Causes can be either primary or secondary.

Plasmapheresis is efficacious for severe hypertryceridemia in patients who have not responded to previous therapies.

We have treated 15 cases of hypertrygliceridemia complicating the course of patients receiving Cyclosporin A after bone marrow transplantation. Five patients were treated with plasmapheresis, the other ten with cascade filtration. The removal rate for triglycerides was 58.0% for patients treated by cascade filtration and 63.5% for patients treated by plasmapheresis. The removal rates for triglycerides were low possibly as a consequence of early saturation of the filter.

[Effect of ursodeoxycholic acid combined with statins in hypercholesterolemia treatment: a prospective clinical trial]

INTRODUCTION

A possible synergistic effect of the combination treatment with statins and ursodeoxycholic acid (UDCA) for reduction of total cholesterol and LDL cholesterol plasma levels has been suggested.

PATIENTS AND METHODS

Random prospective clinical trial in 48 patients with primary or family hypercholesterolemia nonrespondent to simvastatin or atorvastatin treatment. The patients were assigned to a double statin dose group or to a group of combined treatment with simvastatin or atorvastatin and ursodeoxycholic acid for 4 months. Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides plasma levels were evaluated.

RESULTS

The administration of simvastatin 20 mg/day + UDCA 300 mg/day yielded significantly greater reduction of LDL cholesterol plasma levels compared with the group of patients treated with simvastatin 40 mg/day (118.8 +/- 8.6 vs 154.8 +/- 12.2, respectively; p = 0.0034). Moreover, addition of atorvastatin 20 mg/day to UDCA 300 mg/day was more effective that atorvastatin 40 mg/day in single-dose for LDL cholesterol reduction after 4 months of treatment (94.6 +/- 6.1 versus 138.7 +/- 9.0, respectively; p = 0.0037). No significant adverse effects were observed in any of the analyzed groups.

CONCLUSIONS

Our results suggest the effectiveness of combination therapy with statins at low doses and UDCA in the treatment of patients with primary or family hypercholesterolemia initially nonrespondent to low doses of simvastatin or atorvastatin.

Analysis of protein absorbed by LDL column (Liposorber) with special reference to complement component factor D

BACKGROUND

A dextran sulfate column (Liposorber) has been developed and proven effective in LDL apheresis for removing LDL from patients with hyperlipemia. Chronic renal failure (CRF) patients with arteriosclerosis obliterans (ASO) treated with Liposorber have been shown good results.

METHODS

We analyzed proteins absorbed by Liposorber in CRF patients with ASO by means of 2-dimensional electrophoresis and found some noteworthy protein spots. One of these proteins was purified by Sephacryl S-100 column and DEAE Sepharose fast flow column chromatography.

RESULTS

The purified protein was finally identified as complement factor D by Western blotting. The average of recovery amount from three experiments was 6.5 mg. The total recovered amount of factor D was calculated to be about 21.7% out of the estimated amount of factor D in the plasma of CRF patients with ASO receiving LDL apheresis using Liposorber.

CONCLUSIONS

These results indicate that Liposorber absorbs factor D remarkably well.

Comparison of two filter combinations for low-density lipoprotein apheresis by membrane differential filtration: a prospective crossover controlled clinical study

Membrane differential filtration is an accepted procedure for the extracorporeal removal of low-density lipoprotein (LDL). Reduction rates largely depend on the nature of the membranes and are ideally evaluated in a crossover study design. Four patients who had been treated by LDL apheresis for at least 6 months were included. Six consecutive weekly sessions (40 ml plasma/kg body weight) were scheduled per system (Plasmacure PS06/Evaflux Eval 5A [Kuraray] versus Plasmaflo OP05W/Cascadeflo AC1770 [Asahi]). Laboratory measurements indicated reductions of plasma concentrations for fibrinogen (37% [Kuraray] versus 44% [Asahi]), IgG (15% versus 20%), IgA (24% versus 28%), IgM (63% versus 53%), and total protein (11% versus 16%). Total cholesterol was eliminated by 52% versus 49%, LDL by 67% versus 66%, triglycerides by 56% versus 41%, and high-density lipoprotein by 10% versus 20%. Three therapies employing the Asahi filter combination were terminated prematurely due to saturation of the plasma fractionator. In conclusion, despite similar physical properties, the membranes differ significantly concerning selectivity and sensitivity to saturation.

Three low density lipoprotein apheresis techniques in treatment of patients with familial hypercholesterolemia: a long-term evaluation

Low density lipoprotein (LDL) apheresis is a treatment option for patients with severe hypercholesterolemia not adequately responding to drug treatment who have developed coronary heart disease. We regularly treated 18 patients with immunoadsorption, 8 with heparin induced extracorporeal LDL precipitation (HELP) and 8 with dextran sulfate adsorption for a mean of 4.6 +/- 2.6 years. The effects on LDL cholesterol, high density lipoprotein (HDL) cholesterol, and lipoprotein (a) were comparable among all 3 techniques. Twelve patients were treated for longer than 5 years and 18 patients for longer than 3 years. The evaluation of coronary angiograms (23 patients) revealed a definite regression of coronary lesions in 3 patients; in all other patients, there was a halt in progression. Three patients suffered a sudden cardiac death and 1 patient a nonfatal myocardial infarction due to the occlusion of a coronary bypass. In 9 of 11 patients, no atherosclerotic lesions developed in the coronary bypasses. No severe side effect of either procedure was observed. In conclusion, aggressive lipid lowering by LDL apheresis can stabilize coronary atherosclerosis in most patients.

Low-density lipoprotein (LDL) oxidizability before and after LDL apheresis

Oxidation of low-density lipoprotein (LDL) plays a major role in the development of atherosclerosis. Hypercholesterolemia has been associated with enhanced in vitro oxidation of LDL, and lipid-lowering therapy reduces LDL oxidizability. In the present study, we investigated whether LDL apheresis performed with different techniques affects in vitro diene formation (lag phase) and modification of apolipoprotein B-100 (apoB). Baseline and posttreatment diene formation was correlated with the baseline pattern of plasma total fatty acids. We then performed a computer-simulation study to test the hypothesis that LDL apheresis-induced changes in LDL oxidizability are related to changes in the mass ratio between freshly produced and older LDL. In 19 patients aged 49+/-7 years with heterozygous familial hypercholesterolemia (FH) regularly treated with either immunoadsorption, heparin-induced LDL precipitation (HELP), or dextran sulfate (DS) adsorption, we determined lipoprotein levels, the lag phase, apoB modification, and the fatty acid pattern in plasma samples drawn at the onset and termination of one LDL apheresis. LDL apheresis significantly decreased total cholesterol, high-density lipoprotein (HDL) cholesterol, LDL cholesterol, and triglycerides by 50.4%, 14.9%, 62.6%, and 33.6%, respectively. The lag phase increased by a significant mean of 9.8%; the charge of apoB was not altered. The lag phase before treatment positively correlated with the baseline concentration of plasma total palmitic, myristic, and oleic acid. The increase in the lag phase during treatment correlated with a high pretreatment concentration of lauric, linoleic, and docosahexanoic acid. The simulation study indicates that a temporary imbalance between two LDL compartments, one representing freshly secreted LDL and the other representing older LDL, could explain the observed increase in the lag phase after LDL apheresis. In conclusion, in patients with heterozygous FH, LDL apheresis performed with different techniques decreases the susceptibility of LDL to oxidation. This decrease may be related to a temporary mass imbalance between freshly produced and older LDL particles. Furthermore, the baseline fatty acid pattern influences pretreatment and posttreatment susceptibility to oxidation.

Application of bioaffinity technology in therapeutic extracorporeal plasmapheresis and large-scale fractionation of human plasma

This paper describes the increasingly unique and powerful role that affinity chromatography is occupying both as a tool for the treatment of extracorporeal plasma exchange (to discard biological compounds with noxious metabolic or immunologic effects in patients) and as a purification tool in the production of therapeutic plasma protein derivatives. Management of both applications requires careful monitoring of the parameters applied to the plasma material, to avoid immunological stimulation or activation of the coagulation cascade. Examples of direct current applications of affinity ligands in therapeutic removal and industrial production of plasma compounds are presented.

Long-term effect of low-density lipoprotein apheresis on plasma lipoproteins and coronary heart disease in native vessels and coronary bypass in severe heterozygous familial hypercholesterolemia

Low-density lipoprotein (LDL) apheresis is a potent treatment for patients with coronary heart disease and severe hereditary forms of LDL hypercholesterolemia not adequately responsive to drug treatment. Until now, the beneficial effect of aggressive reduction of LDL cholesterol by LDL apheresis on the course of coronary heart disease has been demonstrated in one 3-year study and several studies lasting 2 years. We now report on the clinical course, lipoprotein concentrations, coronary angiograms, and side effects in patients undergoing LDL apheresis for as long as 8.6 years. Thirty-four patients (21 men and 13 women) with coronary heart disease and heterozygous familial hypercholesterolemia (FH) not adequately responsive to lipid-lowering drugs received weekly (four patients biweekly) LDL apheresis for 4.6 +/- 2.6 years under diet and lipid-lowering drug therapy; after 0.5 to 3 years, simvastatin in the maximal tolerable dose was added. The baseline LDL cholesterol concentration was 6.9 +/- 1.6 mmol/L. Combined treatment in the steady state yielded a pretreatment and posttreatment LDL cholesterol concentration of 4.8 +/- 0.9 and 1.8 +/- 0.4 mmol/L, respectively. The calculated interval mean LDL cholesterol was 3.3 +/- 0.6 mmol/L. Evaluation of the coronary angiographies revealed a definite regression of coronary lesions in four patients (11.8%); in 19 patients, there was a cessation of progression. Two patients developed atheromatous lesions in bypass grafts (L.H., 60% stenosis; S.M., occlusion). Of 23 patients eligible for the scoring of anginal symptoms, five (21.7%) reported a reduction of the frequency and severity of angina pectoris. The mean coronary symptom score in 23 patients changed from 1.65 +/- 0.83 at baseline to 1.39 +/- 0.66 at the end of the study. During the whole observation period, we observed three sudden deaths, one nonfatal myocardial infarction, and five patients requiring hospital admission because of unstable angina pectoris, one of which was followed by a transluminal coronary angioplasty. Aggressive reduction of LDL cholesterol with combined LDL apheresis and drugs induced regression of coronary lesions in four of 34 patients and prevented progression in 29 patients for as long as 8.6 years. The effect on LDL and high-density lipoprotein (HDL) cholesterol and lipoprotein(a) [Lp(a)] was comparable with all three apheresis techniques. Therefore, no obvious difference between the three techniques was found regarding changes in coronary lesions.

Short- and long-term effects on serum lipoproteins by three different techniques of apheresis

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 + or - 3 mg/dl with immunoadsorption, 122 + or - 2 mg/dl with HELP, and 124 + or - 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 acyltransferase 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.

Development of immunosorbents for apoB-containing lipoproteins apheresis

Three types of sorbents were developed for the specific removal of atherogenic apoB-containing low-density lipoprotein (LDL) and lipoprotein LDL (a) (Lp[a]) from human plasma. Two sorbents contained monospecific sheep polyclonal or mouse monoclonal antibodies against human apoprotein B-100. The third one was intended for specific removal of Lp(a) and contains sheep antibodies against human Lp(a). Thirty patients were treated for up to 9 years by LDL apheresis with anti-LDL immunosorbents. A pilot study of Lp(a) apheresis with 3 patients was conducted during 3 years. The results showed that extracorporeal immunosorption is safe and effective for lowering LDL and Lp(a). These procedures may be used both for metabolic investigations and for studies on possible regression of atherosclerosis.

Low-density lipoprotein apheresis as long-term treatment for children with homozygous familial hypercholesterolemia

OBJECTIVE

To determine the safety and efficacy of long-term dextran sulfate-affinity column low-density lipoprotein (LDL) apheresis for the treatment of children with receptor-negative homozygous familial hypercholesterolemia (HFH).

STUDY DESIGN

Two children with HFH (pretreatment cholesterol levels 22.1 to 24.7 mmol/L (ranges 850 to 950 mg/dl) began LDL apheresis treatments at ages 7 and 10 years, respectively. The LDL apheresis treatment interval was generally either 7 or 14 days; for the last 2 years of the study the treatment interval was 7 days. The patients had 167 and 188 LDL apheresis procedures during 64 and 70 months, respectively.

RESULTS

Individual procedures decreased total blood cholesterol levels by 63% to 68%. When the treatment interval was 7 days, the patients' time-averaged mean total cholesterol levels decreased to 7.3 +/- 0.65 mmol/L (280 +/- 25 mg/dl) and 6.4 +/- 0.55 mmol/L (247 +/- 22 mg/dl), respectively. Both children remained clinically well with normal growth and development. There was significant regression of xanthomas in both patients. The older patient required heart surgery for preexisting aortic stenosis and coronary ostial stenosis, but neither patient had progression of hypercholesterolemia-related cardiovascular disease. With the exception of iron (deficiency in patient 1), there was no evidence of depletion of serum components. Adverse reactions to LDL apheresis were rare and never severe.

CONCLUSIONS

Dextran sulfate-affinity column LDL apheresis is effective long-term treatment for children with receptor-negative HFH.

A new pectin-based material for selective LDL-cholesterol removal

A new material, natural polysaccharide-pectin, was tested for removal of human blood lipoproteins. Pectin was prepared in a granular form with the help of the specifically designed gelification device and tested in batch sorption experiments in vitro for removal of total cholesterol (TC), LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C) from human plasma. Pectin granules removed 40% of TC, 45% of LDL-C, and 36% of HDL-C on average with respect to the initial amounts whereas corresponding values for LA-40 Kanegafuchi adsorbent were 69%, 81%, and 33% in the same experimental conditions (shaking 1 g of sorbent sample with 2 ml of plasma).

Treatment of homozygous familial hypercholesterolemia by plasma exchange and LDL-apheresis

Two girls with familial hypercholesterolemia were treated for 7 years by plasma exchanges (PE) or LDL-apheresis (LA). We compared different methods of treatment; PE with or without reuse of the plasma separator, LA of varying frequency, and LA with or without oral administration of simvastatin. We assessed the long-term results by measuring the blood levels of the biochemical parameters before sessions, and determined the effectiveness of each session by the percentage of decrease in the blood levels between the beginning and the end of the sessions. LA led to a more selective treatment (lowering of LDL cholesterol and maintenance of HDL cholesterol), but the blood levels of total cholesterol before sessions were the same as those obtained by PE. IgG and haemoglobin levels decreased little with LA. The rhythm of one session a week gave better results in LA. Although reuse of the plasma separator represents a financial saving it produced poorer results. The oral administration of simvastatin improved the results of LA.

Three-year treatment of familial heterozygous hypercholesterolemia by extracorporeal low-density lipoprotein immunoadsorption with polyclonal apolipoprotein B antibodies

Familial hypercholesterolemia is a disorder of lipid metabolism associated with a highly increased risk for cardiovascular disease. Since in such patients even combined drug therapy often fails to decrease low-density lipoprotein (LDL) cholesterol levels sufficiently, extracorporeal LDL elimination has been developed. We treated eight adult patients with LDL immunoadsorption using antibodies against apolipoprotein B without additional lipid-lowering drug therapy for 3 years; this procedure was performed at weekly intervals. By one treatment session, LDL cholesterol and lipoprotein(a) levels were decreased by 55%. Under regular treatment, mean LDL cholesterol levels of 165 mg/dL between two consecutive treatment sessions could be reached, compared with 522 +/- 24 mg/dL before any treatment. As high-density lipoprotein (HDL) cholesterol levels increased under regular treatment, the LDL/HDL cholesterol ratio decreased from 13.4 to 3.4. Positive influences on plasma and whole-blood viscosity as well as on erythrocyte aggregation also seem to be beneficial with regard to retarding atherosclerosis. Very-low-density lipoprotein (VLDL) levels were reduced by approximately 50% after treatment, accompanied by a marked increase of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activity. The effects of LDL apheresis on hemostasis, complement activation transport proteins, and hematological parameters were found to be small. In addition, no side effects amounting to any major clinical relevance occurred in any of the patients. After 3 years of LDL apheresis, a decrease in the frequency of anginal chest pain and ST segment depression on exercise testing and a marked reduction of tendon xanthoma size were observed.

Extracorporeal circuit heparinization in selective low density lipoprotein apheresis: changes in patient hemostasis and low molecular weight heparin benefit

Treatment by low density lipoprotein (LDL) apheresis using dextran sulfate columns (DSC) leads to hemostasis alterations with prolonged activated partial thromboplastin time (APTT) of more than 120 seconds. In order to explain this hypocoagulability, we studied hemostasis parameters both in patients and in the extracorporeal circulation (ECC). Hemostasis changes are first related to unfractionated heparin (UFH)--needed to avoid circuit coagulation--which leads to high residual heparinemia in the patient (more than 3 times the recommended level for therapeutic use). Second, the hypocoagulability is induced by a coagulation factor decrease (primarily factors V, VIII, and X) mainly due to an adsorption mechanism on dextran sulfate. Studies on samples from column inflow, outflow, and eluate confirm this mechanism. Low molecular weight heparin (LMWH) can be used in LDL apheresis on DSC without major changes in lipid removal or coagulation factors compared to UFH. The benefit of using LMWH is to reduce residual heparinemia into the therapeutic range.

C3a and C5a anaphylatoxins bind to heparin-based sorbent in low density lipoprotein apheresis: in vitro and in vivo investigations

Plasmasorption on a heparin-based sorbent was performed in vitro. It demonstrated affinity of the C3a and C5a anaphylatoxins for the sorbent: C3a was removed almost completely (97%), and the C5a concentration decreased on average by 55%. The plasma level of C3a and C5a complement components was also monitored during the procedure of clinical extracorporeal low density lipoprotein (LDL) apheresis on the sorbent in patients with familial hypercholesterolemia. A two- to threefold increase in C3a (up to 1,500 ng/ml) was observed after plasma separation by the IBM 2997 cell sorter. Subsequent processing of the plasma through the column led to the low level of C3a detected (less than 50 ng/ml), demonstrating significant uptake of C3a by the sorbent column. The removed C3a was found in the eluate obtained after regeneration of the sorbent with 2 M NaCl solution. No significant increase in C5a was found during the procedure. Nevertheless, some C5a was detected in the eluate from the sorbent. The content of C3a and C5a in patients blood after the treatment was approximately the same as it was initially, 200-500 ng/ml for C3a and less than 10 ng/ml for C5a. The removal of C3a and C5a anaphylatoxins by heparin-based sorbent should be regarded as an advantage of this type of plasmasorbent.

A new apheresis system using a copolymer (polyvinyl alcohol triethylene glycol diacrylate) for removal of LDL from dog whole blood

Studies were undertaken to determine the effectiveness of a copolymer composed of PVA-TEGDA (Poly Vinyl Alcohol TriEthylene Glycol) as a plasma-cholesterol lowering procedure. For a comparative study, five dogs underwent plasmapheresis including the transfusion bag containing gel in the plasma line, while three control dogs underwent the same plasmapheresis without gel. Numerous biological determinations were performed firstly in whole blood circulation before and after treatment over 10 days, and secondly in plasma before and after LDL binding on the gel. In the whole blood circulation, the average significant depletion of cholesterol levels was 31-51% for treated, 0-16% for control dogs and the average significant depletion of LDL cholesterol was 26-75% for treated and 0-3% for control dogs. Gel was therefore able to bind 121-217 mg of total cholesterol and 34-70 mg of LDL cholesterol per gram of gel. Lipid and lipoprotein levels rebounded 3-4 days after treatment. Adverse effects were not observed during all plasmapheresis. No significant differences between control plasmapheresis and gel-plasmapheresis were obtained for blood cell counts while lengthened coagulation times were observed during 24 h. Complement was not significantly activated by the copolymer as shown by a same decreased activity in the blood stream of all dogs: in fact, CH 50 depletion in the gel incubated plasma was due to a protein adsorption on the hydrogel. This new approach for LDL apheresis appears to be a promising new technique.

Application of a new LDL apheresis system using two dextran sulfate cellulose columns in combination with an automatic column-regenerating unit and a blood cell separator

Extracorporeal procedures for selective removal of low-density lipoproteins have become a promising new approach for treatment of severe familial hypercholesterolemia. We tested efficacy and safety of a new LDL apheresis system by using two dextran sulfate cellulose adsorbents (Liposorber LA 15TM from Kanegafuchi) under the control of an automatic column-regenerating unit for continuous alternate adsorption and desorption. Plasma was taken from a continuous-flow blood cell separator (model IBM/Cobe 2997) allowing an extracorporeal circuit from one cubital vein to another. A 57-year-old male with drug-resistant heterozygous familial hypercholesterolemia accompanied by moderate hypertriglyceridemia and severe coronary artery disease has been treated every 2 weeks for 3 months so far. Treatment of 4-5 liters of plasma resulted in a mean decrease of total cholesterol from 355 to 111 mg/dl (9.20 to 2.88 mmol/l), of LDL cholesterol from 272 to 49 mg/dl (7.05 to 1.53 mmol/l), and of apolipoprotein B from 175 to 44 mg/dl. HDL cholesterol, apolipoprotein A-I, and other plasma proteins did not substantially change apart from hemodilution. No side effects were seen. This new technique of LDL apheresis represents a very effective and safe method for treatment of drug-resistant familial hypercholesterolemia without or with concomitant hypertriglyceridemia.

Heparin-sorbent for low density lipoproteins removal in hypercholesterolemia

Heparin-sorbent was developed in the USSR Cardiology Research Center for LDL-apheresis in patients with familial hypercholesterolemia. Clinical trials of the sorbent were started in 1985. Heparin-sorbent has a high capacity for LDL. One column (400ml) can remove 3 - 6g of LDL cholesterol, depending on the initial LDL content in the plasma. The sorbent demonstrates a high stability, it can withstand more then 75 sorbtion-desorbtion cycles with only a slight loss of the initial capacity. It means that one column can work for 1,5-2,0 years when used weekly. Heparin-sorbent is the sorbent of limited selectivity, apo-B content in eluate is 40-60% of the total protein content, but it is important that it does not bind HDL.

Plasmapheresis: technique and complications

Plasmapheresis has been used in an increasing number of diverse conditions over the past 15 years, and patients on intensive care units are sometimes so treated. This article reviews the principles, different techniques and refinements available, including the more specific methods of antibody removal, such as immunoadsorption. The vascular access, anticoagulation, choice of fluid replacement and monitoring requirements are discussed. The reported possible complications of plasmapheresis, relating both to the practical aspects of the procedure and to the effects of plasma removal and the replacement fluids, are reviewed.

Selective removal of triglyceride-rich lipoproteins by plasmapheresis in diabetic patients with severe hypertriglyceridemia

Two diabetic patients with marked intractable hypertriglyceridemia under treatment with hemodialysis for chronic renal failure were treated by either an apolipoprotein B-dependent removal of lipoproteins using dextran sulfate cellulose column plasmapheresis or a size-dependent removal of lipoproteins using hollow-fiber filtration plasmapheresis. In one patient, a column packed with hollow fibers was used as a plasma separator and a dextran sulfate cellulose column as an adsorbent. In another patient, because the hollow-fiber column did not separate plasma from whole blood, a centrifuge-type blood cell separator was used for the plasma separation. The amounts of plasma cholesterol, triglycerides, and phospholipids removed by plasmapheresis were 30%, 33%, and 30%, respectively, when the combination of a hollow-fiber column and a dextran sulfate cellulose column was used. Corresponding values were 31%, 29%, and 27%, respectively, when the combination of the centrifuge-type blood cell separator and the hollow-fiber column was used. The efficiency of lipid removal was almost the same with both techniques. As for plasma separation, the centrifuge-type blood cell separator was more efficient than the hollow-fiber column. Some losses of albumin and platelets were observed when combination plasmapheresis using the centrifuge-type blood cell separator and the hollow-fiber column was performed. In conclusion, we prefer the centrifuge-type blood cell separator to the hollow-fiber column for plasma separation of marked hypertriglyceridemia. The second filter must be chosen for each patient according to the size of the lipoproteins.

Apheretic treatment of severe familial hypercholesterolemia: comparison of dextran sulfate cellulose and double membrane filtration methods for low density lipoprotein removal

The two more widely available techniques for the extracorporeal removal of low density lipoproteins (LDL), dextran sulfate cellulose column and double membrane filtration, were comparatively tested in severe familial hypercholesterolemic patients, both acutely and during a continued 3-month treatment. The selective dextran sulfate procedure removed close to 60% of LDL and 16% of high density lipoproteins (HDL) upon each apheresis, vs. 42% and 32%, respectively, in the case of the semi-selective double membrane filtration. Upon long term biweekly treatments, LDL-cholesterol (LDL-C) decreased, with the selective procedure, from a pre-treatment level of 406.0 +/- 40.7 mg/dl to a value fluctuating between 295.4 +/- 33.8 mg/dl and 116.9 +/- 22.0 mg/dl (highest vs. lowest levels) whereas, in the case of double membrane filtration, LDL-C levels ranged between 334.8 +/- 39.8 mg/dl and 192.3 +/- 49.9 mg/dl. HDL-cholesterol levels were somewhat raised, to a higher extent with dextran sulfate apheresis. The LDL/HDL-cholesterol "atherogenic ratio", decreased from a pre-treatment value of 10.27 +/- 3.04 to values ranging between 3.61 and 6.82 with dextran sulfate and between 6.70 and 7.68 with double membrane plasmapheresis.

Alterations in the HDL system after rapid plasma cholesterol reduction by LDL-apheresis

Changes in high density lipoprotein (HDL) subfraction structure and composition were analyzed during and after extracorporeal removal of apo B containing lipoproteins in seven familial hypercholesterolemic (FH) patients. After the apheretic procedure, carried out with dextran-sulfate-cellulose columns, the plasma levels of very low density lipoproteins (VLDL), low density lipoproteins (LDL), and HDL decreased by 72%, 50%, and 19%, respectively. The free cholesterol to esterified cholesterol ratio in plasma increased, with a 26% drop in the lecithin:cholesterol acyl transferase (LCAT) activity. In the ensuing 24 hours, VLDL, HDL, and LCAT activity approached the pretreatment levels. During this phase, possibly as a consequence of increased cholesterol esterification and exchange of cholesteryl esters for triglycerides between HDL and VLDL, HDL2a particles were detected in plasma. However, these metabolic changes did not result in clearcut modifications in the HDL2-HDL3 subfraction distribution. These findings clearly demonstrate that rapid changes in the plasma VLDL-LDL levels affect several processes involved in the HDL metabolism, but confirm that the HDL system, in spite of a considerable plasticity, displays a marked stability of the HDL2-HDL3 subfraction distribution.

Acute and long-term effects of low-density lipoprotein apheresis on the serum concentrations of vitamins E and A

Serum alpha-tocopherol and retinol concentrations were followed in four heterozygous adults and one homozygous child with familial hypercholesterolemia being treated by regular low-density lipoprotein (LDL) apheresis. Approximately 50% of plasma alpha-tocopherol was eliminated during a single apheresis procedure in the heterozygous adults, while a complete elimination of this vitamin along with LDLs was observed in the homozygous child. Absolute losses of alpha-tocopherol amounted to 13.4-22.5 mg/apheresis and are equivalent to the recommended dietary intake for 1.5 to 2 days. Despite these losses, no changes were observed either in serum alpha-tocopherol levels or in the ratio of alpha-tocopherol/total serum lipids after 12 months regular apheresis treatment. Serum retinol concentrations only showed a small decrease on apheresis, there being apparently no specific elimination of this vitamin. The absolute losses ranged from 42-422 micrograms/apheresis and were, therefore, much lower than the recommended dietary intake of the equivalent of 1500 micrograms retinol/day. It is concluded that no extra supplementation of these vitamins is required during LDL-apheresis therapy, although it may be advisable to monitor vitamin E status in patients on long-term, intensive therapy.

Clinical evaluation of three types of plasmapheresis in a patient with type IIa familial hypercholesterolemia

Long-term plasmapheresis (PP) therapy was studied in a 56-year-old patient with homozygous type IIa familial hypercholesterolemia also suffering from severe coronary heart disease. Three different PP techniques, plasma exchange (PE), double-membrane-filtration plasmapheresis (DFP), and the recently developed low-density lipoprotein adsorbent column (adsorption plasmapheresis, adsorption PP), were used in an attempt to develop better means of managing the disease. All three techniques showed similar elimination efficiency with respect to plasma total cholesterol level. Adsorption PP with minimal supplemental plasma protein managed the circulatory status of the patient better than DFP during extracorporeal treatment. In the course of PP therapy xanthoma tuberosum markedly regressed, and the cardiac status of the patient was clearly improved.