Low-density lipoprotein apheresis: an overview

Use of Proprotein Converse Subtilisin/Kexin Type 9 Inhibitor to Treat Cholesterol Crystal Embolisms after Catheterization: A Report of Three Cases

Cholesterol crystal embolism (CCE) is a serious complication that occurs after cardiac and vascular procedures. CCE involves multiple organs, and the prognosis and renal function of patients is poor. Although the efficacy of steroid, statin, and low-density lipoprotein apheresis has been reported, no definitive treatment has been established. We herein report three consecutive cases treated with conventional steroid therapy with proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor after catheterization. The renal function was preserved, steroid therapy was stopped, and wound healing of blue toes was achieved. PCSK9 inhibitor therapy was safe in the present patient and may be a potential treatment option for CCE.

An Autopsy Case of Acute Pancreatitis Caused by Cholesterol Crystal Embolization

Cholesterol crystal embolization (CCE) shows a poor prognosis and it can cause ischemic organ damage due to a cholesterol embolism from atherosclerotic lesions in large blood vessels. Such an embolism mainly affects the kidneys and skin, although cases involving digestive organs have also been reported. We encountered an autopsy case of CCE with damage mainly to the digestive organs, including the pancreas. The patient had non-specific abdominal symptoms or image findings. Symptomatic therapy failed to save him. CCE can involve the digestive organs, and so must be differentiated from abdominal pathologies. Moreover, conventional treatments may be ineffective, and new treatments might thus be necessary.

Successful treatment of cholesterol crystal embolism with anti-proprotein convertase subtilisin/kexin type 9 (PCSK9) antibody: a case report

Background

We report a unique case of renal cholesterol crystal embolism (CCE) induced by carotid artery stenting that was successfully treated with evolocumab, a fully human monoclonal antibody against proprotein convertase subtilisin kexin type 9 (PCSK9).

Case presentation

A 77-year-old man with hypertension, hyperlipidemia, and chronic kidney disease was referred to our department for decreased estimated glomerular filtration rate (eGFR)—from 32.0 to 13.9 mL/min/1.73 m²—5 weeks after carotid artery stenting. Further examination revealed livedo reticularis in the bilateral toes and eosinophilia (723/μL). Skin biopsy from livedo reticularis tissue in the bilateral toes showed cholesterol clefts in the small arteries. The patient was therefore diagnosed with CCE. After 25 weeks’ administration of evolocumab at a dose of 140 mg subcutaneously administered every 2 weeks, his eGFR had improved from 10.7 to 18.1 mL/min/1.73 m².

Conclusion

Evolocumab may have a beneficial effect on renal involvement in patients with CCE.

The Removal of HBV in Plasma by Extracorporeal Immunoadsorption from Plasma: A Potential Therapy of Hepatitis B Patients

Objective

To establish a novel HBV specific immunoadsorbent for the removing of HBV particles.

Methods

The anti-HBsAg monoclonal antibody was immobilized on sepharose beads to produce a sepharose anti-HBs column. Then the immunoadsorbent was evaluated and characterized by scanning electron microscopy. In addition, time-dependent effects of the eradication capacity of anti-HBsAg functionalized sepharose beads against HBV were investigated.

Results

Proposed immunoadsorbents exhibited a favorable biocompatibility as well as specificity. With the optimized recycle time, the decontamination performance of HBV particles and quantity of HBsAg were assessed either by real-time quantitative PCR or ELISA, which showed that the immunoadsorbent could remove approximately 90% of the HBV and 90% of the HBsAg from human plasma samples.

Conclusions

All these results indicated that the novel immunoadsorbent could effectively remove HBV particles and likely serve as a novel therapy option or at least supplementary for the treatment regimen of HBV.

Lipoprotein apheresis in the management of severe hypercholesterolemia and hyperlipoproteinemia(a)-The Portuguese experience

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a) (Lp(a)) are established causal risk factors for cardiovascular disease (CVD). Lipoprotein apheresis is often required for treatment of patients with a high risk for CVD due to hypercholesterolemia and/or hyperlipoproteinemia(a).

AIM

To describe our experience with lipoprotein apheresis in patients with severe hypercholesterolemia or with hyperlipoproteinemia(a).

METHODS

We retrospectively investigated patients treated with Lipoprotein apheresis using direct adsorption of lipoproteins (DALI) technique, between December 2008 and March 2018, in our center. Adverse events, acute and long term reductions in lipid parameters were analyzed.

RESULTS

Between December 2008 and March 2018, a total of 950 treatments were performed in five patients, four with heterozygous familial hypercholesterolemia (HeFH), all on maximally tolerated cholesterol-lowering drug therapy and in one patient with hyperlipoproteinemia(a) and progressive CVD. In the four patients with HeFH we obtained mean acute reductions in LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C) of 62.0 ± 7.8% and 60.4 ± 6.8%, respectively. Regarding long-term efficacy we achieved a mean reduction of 43.1% in LDL-C and of 41.2% in non-HDL-C. In the patient with hyperlipoproteinemia(a) we attained mean acute reductions of 60.4 ± 6.4% in Lp(a) and of 75.4 ± 7.3% in LDL-C per session and long term reductions in Lp(a) and LDL-C of 67.4% and 40.5%, respectively. Adverse events were recorded in only 1.2% of treatments.

CONCLUSION

Lipoprotein apheresis is an efficient and safe treatment in severely hypercholesterolemic patients who are refractory to conservative lipid-lowering therapy or with hyperlipoproteinemia(a) and progressive CVD.

Lipoprotein apheresis in the treatment of dyslipidaemia - the Czech Republic experience

In 1984, we started using therapeutic plasmapheresis (plasma exchange) as a method of extracorporeal lipoprotein elimination for the treatment of hypercholesterolemic patients. We evaluated the results of long-term therapy in 14 patients, 8 men and 6 women. The average age was 55.6+/-13.2 (range 28-70), median 59.5 years. 14 patients were diagnosed with familial hypercholesterolemia (FH): 5 homozygous, 9 heterozygous. Ten patients in the group were treated using immunoadsorption lipoprotein apheresis and 4 using hemorheopheresis. Immunoapheretic interventions decreased LDL-cholesterol (82+/-1 %), ApoB (73+/-13 %) and even Lp(a) by 82+/-19 %, respectively. Selected non-invasive methods are important for long-term and repeated follow-up. Carotid intima-media thickness showed improvement or stagnation in 75 % of the patients. Biomarkers of endothelial dysfunction such as endoglin (in the control group: 3.85+/-1.25 microg/l, in lipoprotein apheresis-treated hypercholesterolemic individuals 5.74+/-1.47 microg/l), CD40 ligand (before lipoprotein apheresis: 6498+/-2529 ng/l, after lipoprotein apheresis: 4057+/-2560 ng/l) and neopterin (before lipoprotein apheresis: 5.7+/-1.1 nmol/l, after lipoprotein apheresis: 5.5+/-1.3 nmol/l) related to the course of atherosclerosis, but did not reflect the actual activity of the disease nor facilitate the prediction or planning of therapy. Hemorheopheresis may improve blood flow in microcirculation in familial hypercholesterolemia and also in some other microcirculation disorders via significantly decreased activity of thrombomodulin (p<0.0001), tissue factor (p<0.0001), aggregation of thrombocytes (p<0.0001) and plasma and whole blood viscosity (p<0.0001). In conclusion, lipoprotein apheresis and hemorheopheresis substantially lowered LDL-cholesterol in severe hypercholesterolemia. Our experience with long-term therapy also shows good tolerance and a small number of complications (6.26 % non-serious clinical complications).

Lipoprotein(a) apheresis

PURPOSE OF REVIEW

Currently, different methods for extracorporeal elimination of atherogenic apolipoprotein B100 containing lipoprotein particles are used in clinical practice. Most of them effectively remove both lipoprotein(a) [Lp(a)] and LDL. The aim of this review is to highlight research describing the clinical advantages of specific Lp(a) immunosorption compared with other lipoprotein apheresis systems.

RECENT FINDINGS

Data on the utility of lipoprotein apheresis in patients with elevated Lp(a) level are limited. However, several longitudinal studies demonstrated improvement in cardiovascular outcomes when both Lp(a) and LDL cholesterol levels were decreased with different apheresis systems. The main limitation of these trials is the absence of a control group. First developed in 1991, studies on apheresis with a specific immunosorbent to Lp(a) were small and noncontrolled before 2000s. The only prospective controlled clinical trial utilising Lp(a) apheresis (Clinicaltrials.gov NCT02133807), demonstrated regression of coronary and carotid atherosclerosis when Lp(a) was removed weekly for 18 months.

SUMMARY

Lipoprotein apheresis usually affects multiple lipoproteins, and there are minimal data regarding the effect of specific removal of Lp(a) alone. There is a need for randomized controlled trial with specific Lp(a) apheresis to investigate its effect on cardiovascular outcomes.

Systematic Review of Low-Density Lipoprotein Cholesterol Apheresis for the Treatment of Familial Hypercholesterolemia

BACKGROUND

Apheresis is an important treatment for reducing low-density lipoprotein cholesterol (LDL-C) in patients with familial hypercholesterolemia (FH). We systematically reviewed the current literature surrounding LDL-C apheresis for FH.

METHODS AND RESULTS

Electronic databases were searched for publications of LDL-C apheresis in patients with FH. Inclusion criteria include articles in English published in 2000-2013 that provide descriptions of practice patterns, efficacy/effectiveness, and costs related to LDL-C apheresis in patients with FH. Data were stratified by country and FH genotype where possible. Thirty-eight studies met the inclusion criteria: 8 open-label clinical trials, 11 observational studies, 17 reviews/guidelines, and 2 health technology assessments. The prevalence of FH was not well characterized by country, and underdiagnosis was a barrier to FH treatment. Treatment guidelines varied by country, with some guidelines recommending LDL-C apheresis as first-line treatment in patients with homozygous FH and after drug therapy failure in patients with heterozygous FH. Additionally, guidelines typically recommended weekly or biweekly LDL-C apheresis treatments conducted at apheresis centers that may last 2 to >3 hours per session. Studies reported a range for mean LDL-C reduction after apheresis: 57-75% for patients with homozygous FH and 58-63% for patients with heterozygous FH. Calculated annual costs (in US$2015) may reach US$66 374 to US$228 956 per patient for weekly treatment.

CONCLUSIONS

LDL-C apheresis treatment may be necessary for patients with FH when drug therapy is inadequate in reducing LDL-C to target levels. While apheresis reduces LDL-C, high per-session costs and the frequency of guideline-recommended treatment result in substantial annual costs, which are barriers to the optimal treatment of FH.

Soy and phytoestrogens: possible side effects

Phytoestrogens are present in certain edible plants being most abundant in soy; they are structurally and functionally analogous to the estrogens. Phytoestrogens have been applied for compensation of hormone deficiency in the menopause. At the same time, soy products are used in infant food and other foodstuffs. Furthermore, soy is applied as animal fodder, so that residual phytoestrogens and their active metabolites such as equol can remain in meat and influence the hormonal balance of the consumers. There have been only singular reports on modified gender-related behavior or feminization in humans in consequence of soy consumption. In animals, the intake of phytoestrogens was reported to impact fertility, sexual development and behavior. Feminizing effects in humans can be subtle and identifiable only statistically in large populations.

Hormesis and homeopathy: The artificial twins

Homeopathy claims a curative reaction from small doses of a substance, high doses of which cause symptoms similar to those the patient is suffering from. Hormesis is a concept of biphasic dose-response to different pharmacological and toxicological agents. According to this concept, a small dose of a noxious agent can exert a beneficial action. A hypothesis is defended here that hormesis as a general principle can be assumed only for the factors present in the natural environment thus having induced adaptation of living organisms. Generalizations of the hormesis phenomenon used in support of homeopathy are unfounded. Low-dose impacts may be associated with a higher risk in a state of organ sub-compensation or failure especially in the elderly patients. Practical recommendations should be based neither on the hormesis as a default approach nor on the postulates of homeopathy. All clinically relevant effects, hormetic or not, should be tested by the methods of evidence-based medicine.

Preventing Early Cardiovascular Death in Patients With Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant disorder resulting in severe elevation of total and low-density lipoprotein cholesterol levels. There are more than 600,000 individuals in the United States with FH. Individuals with FH tend to experience premature cardiovascular disease and often die from sudden cardiac death at a young age. Statins alone or in combination with other lipid-lowering medications are effective in managing FH and preventing cardiovascular events. For patients who do not respond to or are intolerant of pharmacotherapy, low-density lipoprotein apheresis is available as a nonpharmacologic treatment option. Despite the prevalence of FH, it is undiagnosed and untreated in the majority of patients. Screening, combined with appropriate drug therapy, can save lives. The authors review the screening, diagnosis, and management of FH.

Prospective multicentre study of the effect of voluntary plasmapheresis on plasma cholesterol levels in donors

Background and Objectives LDL apheresis is used to treat patients with familial hypercholesterolaemia, and low-volume plasmapheresis for plasma donation may similarly lower cholesterol levels in some donors. This study was designed to assess the effect of plasmapheresis on total, LDL and HDL cholesterol levels in a plasma donor population.

Materials and Methods This was a prospective, unblinded longitudinal cohort study in which a blood sample was obtained for analysis before each donation. Data from 663 donors were analysed using a multivariable repeated measures regression model with a general estimating equations approach with changes in cholesterol as the primary outcome measure.

Results The model predicted a significant decrease in total and LDL cholesterol for both genders and all baseline cholesterol levels (P < 0·01). The greatest total cholesterol decreases (women, −46·8 mg/dL; men, −32·2 mg/dL) were associated with high baseline levels and 2–4 days between donations. Small but statistically significant increases (P ≤ 0·01) in HDL cholesterol were predicted for donors with low baseline levels.

Conclusions These results suggest that, in donors with elevated baseline cholesterol levels, total and LDL cholesterol levels may decrease during routine voluntary plasmapheresis.

Double filtration plasmapheresis in different diseases in Thailand

Double filtration plasmapheresis (DFPP) was applied to the treatment of two different categories from 100 cases that had been collected over a 5 year period (2007-2011). These categories were allocated into groups by size of toxic substances, which were classified as two different kinds of diseases. Group I comprised diseases that were caused by alloimmunity in transplantation, autoimmune diseases, complicated nephrotic syndrome, pure red cell aplasia, and toxemia of pregnancy. This group was treated with a plasma separator (plasmaflow-05, Asahi Kasei) and plasma fractionators, EC-20W. The second group, which included hyperviscosity syndrome, was treated by the same plasma separator, but with different plasma fractionators using EC-40W. This group included diabetes nephropathy, hyperlipidemia, peripheral arterial diseases, and neurosensory hearing loss. Both groups used 1.5 plasma volumes in each treatment for three sessions in two consecutive weeks. The result of treatment in group I showed that plasma immunoglobulin G (IgG) was decreased substantially by 66% in either transplant or lupus nephritis patients after the third session. In the second group, IgM, fibrinogen, and lipid markedly responded to the treatment. Two diabetes nephropathy patients showed stable renal function for more than 12 months. Peripheral arterial disease was shown to benefit from significantly decreasing fibrinogen and IgM, which resulted in clinical tissue oxygenation. Neither bleeding diathesis nor membrane anaphylaxis were reported from the treatment. In summary, apheresis patients were shown to benefit in hypersensitized and hyperviscosity syndrome.

LDL-apheresis: technical and clinical aspects

The prognosis of patients suffering from severe hyperlipidemia, sometimes combined with elevated lipoprotein (a) levels, and coronary heart disease refractory to diet and lipid-lowering drugs is poor. For such patients, regular treatment with low-density lipoprotein (LDL) apheresis is the therapeutic option. Today, there are five different LDL-apheresis systems available: cascade filtration or lipid filtration, immunoadsorption, heparin-induced LDL precipitation, dextran sulfate LDL adsorption, and the LDL hemoperfusion. There is a strong correlation between hyperlipidemia and atherosclerosis. Besides the elimination of other risk factors, in severe hyperlipidemia therapeutic strategies should focus on a drastic reduction of serum lipoproteins. Despite maximum conventional therapy with a combination of different kinds of lipid-lowering drugs, sometimes the goal of therapy cannot be reached. Hence, in such patients, treatment with LDL-apheresis is indicated. Technical and clinical aspects of these five different LDL-apheresis methods are shown here. There were no significant differences with respect to or concerning all cholesterols, or triglycerides observed. With respect to elevated lipoprotein (a) levels, however, the immunoadsorption method seems to be most effective. The different published data clearly demonstrate that treatment with LDL-apheresis in patients suffering from severe hyperlipidemia refractory to maximum conservative therapy is effective and safe in long-term application.

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.

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

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

Extracorporeal LDL cholesterol elimination (25 years of experience in CZ)

In the Czech Republic the therapy of severe familial hypercholesterolemia (FH) by extracorporeal elimination using LDL-apheresis (immunoadsorption) and hemorheopheresis is concentrated into one center. The authors evaluate the long-term therapy (3-12 years, median 7,25) in 12 patients with FH - 3 homozygous, 9 heterozygous; Fredrickson type IIa, IIb (treated: 9 by LDL-apheresis and 3 by hemorheopheresis). Immunoapheretic interventions decrease LDL-cholesterol, ApoB and even Lp(a) by about 82 +/- 1; 73 +/- 13; 82 +/- 19 %, respectively. Selected non-invasive methods are important for a long-term and repeated follow-up. Carotid intima-media thickness showed improvement or stagnation in 75% of the patients. The level of some adhesive molecules, cytokines, endoglin and some coagulation functions were measured, but no universally accepted biomarkers informing of the actual activity of the disease were found to predict and plan the therapy. A program for procedure planning with the use of Microsoft® Excel for Windows® was developed. In summary, LDL-apheresis and hemorheopheresis substantially lower LDL-cholesterol in FH. Our experience with long-term therapy also shows good tolerance and a small number of complications (5,6% of clinically irrelevant side-effects). Hemorheopheresis may improve blood flow in microcirculation in familial hypercholesterolemia and also in some other disorders of microcirculation.

Low-density lipoprotein apheresis reduces platelet factor 4 on the surface of platelets: a possible protective mechanism against heparin-induced thrombocytopenia and thrombosis

BACKGROUND

Heparin-induced thrombocytopenia and thrombosis (HITT) is characterized by thrombocytopenia due to the formation of antibodies against heparin : platelet factor 4 (PF4) complexes. Despite the exposure to heparin during treatment and predisposition of patients with atherosclerosis to HITT, HITT in patients undergoing low-density lipoprotein (LDL) apheresis is rare. We investigated the possibility that LDL apheresis decreases PF4 on platelet (PLT) surfaces and/or plasma HITT antibody levels, either of which would disfavor HITT.

STUDY DESIGN AND METHODS

We enrolled 25 patients undergoing LDL apheresis at the Hospital of the University of Pennsylvania. Blood samples were drawn before and after treatment. Plasma samples were drawn proximal and distal to the LA-15 treatment column. PF4, HITT antibodies, heparin levels, and P-selectin were measured.

RESULTS

No patient had clinical symptoms of HITT. The LA-15 column was found to efficiently remove PF4. PF4 levels in peripheral blood plasma did not change significantly after LDL apheresis. However, PLT surface PF4 significantly decreased after treatment. HITT antibodies were found in only two patients and were nonfunctional. PLT surface P-selectin did not change during treatment.

CONCLUSIONS

We have demonstrated that LDL apheresis via dextran sulfate absorption removes plasma PF4 and reduces the amount of PF4 on the surface of circulating PLTs. Reduced surface PF4 may decrease antibody formation and/or recognition by HITT antibodies. These data provide a potential explanation for the near lack of HITT in hypercholesterolemic patients undergoing LDL apheresis. They also suggest the possibility that LDL apheresis using dextran sulfate adsorption may have therapeutic value in the treatment of HITT.

Immobilization of heparin on polysulfone surface for selective adsorption of low-density lipoprotein (LDL)

A versatile method was developed to immobilize heparin covalently on polysulfone sheets (PSu) to achieve selective adsorption of low-density lipoprotein (LDL). This was achieved by activation of PSu with successive treatments of chlorodimethyl ether and ethylenediamine, and subsequent chemical binding of heparin with bifunctional linker molecules. A heparin density up to 0.86 microg cm(-2) on a dense PSu film was achieved. The modified PSu films were characterized by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The hydrophilicity of the PSu film was improved greatly by covalent immobilization of heparin. The water contact angle of PSu film was decreased from 86.6 + or - 3.7 degrees to 50.5 + or - 3.2 degrees after binding of 0.36 microg cm(-2) heparin. An enzyme-linked immunosorbent assay was used to measure the binding of LDL on plain and modified PSu films. It was found that the heparin-modified PSu film could selectively recognize LDL from binary protein solutions. Furthermore, it was possible to desorb LDL from heparinized PSu, but not from plain PSu, with heparin, sodium chloride or urea solution, which indicates a selective but reversible binding of LDL to heparin. The results suggest that heparin-modified PSu membranes are promising for application in simultaneous hemodialysis and LDL apheresis therapy.

High lipoprotein (a) levels are associated with an increased risk of retinal vein occlusion

INTRODUCTION

Retinal vein occlusion (RVO) is one of the most common retinal vascular disorders affecting ocular vessels. Few studies, with conflicting results and conducted in limited study populations, have hypothesised the role of high levels of lipoprotein (a) [Lp(a)] in the occurrence of RVO. The aim of this study was to investigate, in a large group of RVO patients, the role of such an emerging thrombophilic parameter on the pathogenesis of RVO.

MATERIALS AND METHODS

We compared 262 patients [median age: 66 years (15-88); 122 M, 140 F] with 262 age- and sex-comparable healthy subjects.

RESULTS

Circulating concentrations of Lp(a) were found to be significantly different in patients when compared to healthy subjects [189 (60-1898)mg/L vs. 119.5 (6-1216)mg/L; p<0.0001, respectively]. No significant differences were observed relating to the different types of occlusion (central or branch occlusion). In order to investigate the possible association between high Lp(a) levels and the disease we performed a logistic regression analysis. In the univariate analysis, Lp(a) levels>300mg/L were found to be associated with an increased risk of RVO (OR: 2.39, 95%CI 1.39-3.59; p<0.0001). Following this, three models of multivariate analysis were performed, firstly by adjusting for age, gender, and traditional cardiovascular risk factors, secondly for triglycerides and thirdly for homocysteine levels. In all the models, Lp(a) levels>300mg/L confirmed their role as a risk factor for RVO [first model, OR: 2.15 (95%CI 1.39-3.32), p=0.0001; second model, OR: 3.11 (95%CI 1.77-5.62), p<0.00001; third model, OR: 3.48 (95%CI 1.88-6.43), p<0.00001].

CONCLUSIONS

This study reports that, in a large population of RVO patients, high Lp(a) concentrations are significantly related to RVO, independent from other traditional and emerging risk factors, suggesting that they may play a role in its pathogenesis.

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.

LDL-apheresis: indications and clinical experience in a tertiary cardiac centre

OBJECTIVE

To determine the efficacy and safety of liposorber D low-density lipoprotein (LDL) apheresis system in high-risk cardiac patients.

DESIGN

Retrospective analysis of 466 treatments undertaken in eight patients with coronary heart disease. Five patients had severe heterozygous familial hypercholesterolaemia (FH), one had severe hypertriglyceridaemia and two were cardiac transplant recipients with FH intolerant to statins. Acute reductions during single sessions and preprocedural long-term changes in lipoprotein subfractions, laboratory safety parameters, adverse events and clinical outcome were recorded.

RESULTS

In 352 treatments performed in seven patients, acute reductions averaged 52.8% (standard deviation: 8.61%) for total cholesterol (TC), 61.8% (10.13%) for LDL-cholesterol (LDL-C), 21.1% (9.66%) for high-density lipoprotein cholesterol (HDL-C), 71.1% (median) for lipoprotein (a) [Lp(a)] and 44.5% (14.42%) for triglycerides (p < 0.05). Long-term reductions of TC, LDL-C, Lp(a) and triglycerides by 18.1%, 21.7%, 9.4% (median) and 19.8%, respectively, were achieved. HDL-C was increased by 7.5%. Results from the patient with severe hypertriglyceridaemia were analysed separately because of markedly elevated TC and triglycerides. Technical and clinical complications were mild and showed an incidence of 16.65% and 12.45% respectively. The most common clinical event was transient hypotension (5.8%), whereas vascular access difficulties (11.3%) represented a common technical problem. All patients demonstrated clinical improvement. However, two patients treated via a central line developed septicaemia, resulting in endocarditis in one of them.

CONCLUSION

Liposorber D is a simple, safe and effective modality in reducing atherogenic lipoproteins in dyslipidaemic high-risk cardiac patients. The treatment via an arteriovenous fistula is the preferred vascular access in this type of patient.

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.

Low-density Lipoprotein Apheresis Therapy With a Direct Hemoperfusion Column: A Japanese Multicenter Clinical Trial

Low-density lipoprotein (LDL) apheresis has been applied to patients with familial hypercholesterolemia (FH) with coronary artery disease (CAD). To examine the efficacy and safety of a new type of LDL adsorption column (KLD01, Kaneka, Osaka, Japan), which deals with whole blood without separating plasma, the new system was evaluated in a multicenter trial. The present study included 33 FH patients with CAD (24 males, 9 females, 57 +/- 13 years) who were treated five times with a mean interval of 2.12 +/- 0.60 weeks between treatments. We studied the removal efficacies for serum LDL cholesterol, Lipoprotein(a) (Lp(a)) and triglyceride, the times for the preparation of the system and for treatment, symptoms, and the biochemical data. The scheduled treatments were completed by 31 patients. Serum levels of LDL cholesterol, Lp(a) and triglycerides were all significantly reduced with KLD01; 61.5 +/- 6.2%, 72.4 +/- 5.9% and 69.5 +/- 9.7%, respectively. The times for both setting up the column system (26 +/- 7 min) and treatment (138 +/- 20 min) were shorter with KLD01 than conventional methods. Adverse reactions occurred in eight cases (17 episodes), but the patients fully recovered immediately after each apheresis therapy session. We conclude that the new type of LDL adsorption column, one that deals with whole blood, is a promising apheresis therapy for FH patients in view of its efficacy, reduced time for treatment, and safety.

Nonpharmacologic Approaches for the Treatment of Hyperlipidemia

Coronary heart disease (CHD) is the leading cause of death in the United States. Dyslipidemias, like decreased high-density lipoprotein (HDL) and increased low-density lipoprotein (LDL), have been linked through epidemiologic and experimental studies with the development of atherosclerosis and an increased risk of CHD. The introduction of various classes of lipid-lowering drugs, especially the hydroxymethylglutaryl-coenzyme-A-reductase inhibitors (statins), has allowed for effective treatment of hyperlipidemia. This article reviews the following nonpharmacologic approaches to hyperlipidemia: LDL apheresis, surgery, the emergence of HDL as a therapeutic target, gene therapy, and finally, the possibility of developing a vaccine against atherosclerosis.

Lipoprotein(a) as a cardiovascular risk factor

Evidence for the role of lipoprotein(a) (Lp[a]) in atherosclerosis and thrombosis has considerably increased over the past few years. Therefore, Lp(a) is currently classified as an emerging lipid risk factor for cardiovascular disease. High Lp(a) plasma levels carried in particles with small-sized apolipoprotein(a) isoforms are associated with preclinical vascular changes, cardiovascular disease and the mode of presentation of coronary artery disease (acute coronary syndromes). However, randomized clinical trials with an emphasis on agents that specifically lower plasma Lp(a) do not exist. At present, screening for increases in Lp(a) in the general population is not recommended. The measurement of Lp(a) may be of value in individuals with an increased risk of cardiovascular disease, particularly in patients with high low-density lipoprotein cholesterol plasma levels, since a high Lp(a) concentration in such subjects further increases the risk of coronary heart disease.

Clinical applications of long-term LDL-apheresis on and beyond refractory hypercholesterolemia

Premature coronary heart disease (CHD) can result from high LDL cholesterol levels even in the absence of any other risk factors. A striking example is found in children who have the homozygous form of familial hypercholesterolemia (FH) with extremely high levels of LDL-cholesterol, and severe atherosclerosis and CHD often develop during the first decades of life. LDL-apheresis was developed for the treatment of severe type of FH patients who are resistant to lipid-lowering drug therapy. Clinical efficacy and safety of the therapeutic tool which directly removes LDL from circulation have already been established in the treatment for refractory hypercholesterolemia in FH patients. The most recently developed method enables lipoproteins to be adsorbed directly from whole blood, using polyacrylate column. In addition to benefits derived from the stabilization or regression of arterial lesions, we highlight other possible clinical applications of LDL-apheresis. However, most of these clinical benefits came from case reports or retrospective studies. Mechanisms related these clinical improvement remain unclear, and prospective randomized controlled trials should be performed for the new clinical indications of LDL-apheresis.

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.