LDL apheresis reduces the susceptibility of LDL to in vitro oxidation in a diabetic patient with hemodialysis treatment

Heparin-Mediated Extracorporeal Low-Density Lipoprotein Precipitation Apheresis for Treating Peripheral Arterial Disease in Patients with Chronic Kidney Disease

Patients with chronic kidney disease (CKD), particularly those with end-stage renal disease (ESRD), have a high prevalence of cardiovascular disease and peripheral arterial disease (PAD). Medical treatment is mainly based on risk factor management, and the surgical approach remains the gold standard treatment in specific conditions. Heparin-mediated extracorporeal low-density lipoprotein precipitation (H.E.L.P.) apheresis is effective in reducing circulating lipoprotein, fibrinogen, inflammatory mediators and procoagulant factors, thereby reducing cardiovascular risk in patients with familial hypercholesterolemia and hypertriglyceridemia. These activities may be effective in reducing symptoms and ischemic vascular lesions even in patients with severe PAD. We reported the application of a treatment protocol with H.E.L.P. apheresis in an ESRD patient with severe PAD without clinical improvement after severe revascularization who was not suitable for further surgical approaches, despite normal LDL cholesterol and lipoprotein (a). The H.E.L.P. protocol was characterized by an intensive first phase with weekly treatments followed by a single session every 10-15 days for 6 months of treatment. The overall clinical condition, foot lesions and walking distance improved significantly after the first 2 months of treatment, and foot amputation was avoided. Here, we review the main pathogenetic mechanisms through which LDL apheresis improves microcirculation and clinical outcomes. Its wider application may represent an optimal therapeutic option for patients unresponsive to standard treatment.

Effect of an oral astaxanthin prodrug (CDX-085) on lipoprotein levels and progression of atherosclerosis in LDLR(-/-) and ApoE(-/-) mice

Oxidative stress and inflammation are key promoters of atherosclerosis and myocardial damage. When orally administered, the novel astaxanthin prodrug CDX-085 delivers high levels of the xanthophyll antioxidant astaxanthin that protects LDL from oxidation and reduces primary thrombosis. In this study, we analyzed whether delivery of astaxanthin from administration of the CDX-085 prodrug reduces plasma lipoprotein levels and the progression of atherosclerosis in low-density lipoprotein receptor negative (LDLR(-/-)) and apolipoprotein E deficient (ApoE(-/-)) mice.

METHODS

Relative circulating levels of astaxanthin derived from CDX-085 administration compared to administration of pure astaxanthin was initially evaluated in a canine model. In mouse Study #1, 16 wild-type and 16 LDLR(-/-) mice on 0.5% cholesterol diet supplemented with either 0.0%, 0.08%, 0.2% and 0.4% CDX-085 were used to assess plasma levels and lipoprotein biodistribution measured by FPLC after 4 weeks treatment. In Study #2, 36 male LDLR(-/-) mice were randomized to a 0.5% cholesterol chow diet (CHOW group, n=12) or 0.5% cholesterol chow fortified with 0.08% CDX-085 (n=12) or 0.5% cholesterol chow with 0.4% CDX-085 (n=12) for 12 weeks. In Study #3, 34 male ApoE(-/-) mice were randomized in the same fashion as the Study #2 and fed similar diets for 9 weeks.

RESULTS

CDX-085 administration was shown to result in significantly higher levels of circulating astaxanthin (p<0.001 ANOVA) over a 72 h period compared to pure, non-esterified astaxanthin in a single-dose pharmacokinetic study in beagles. In Study #1, plasma astaxanthin levels were 5-9-fold higher in LDLR(-/-) mice compared to wild-type mice. Astaxanthin was highly distributed among all lipoprotein fractions, generally reflecting cholesterol content of lipoproteins. In Study #2, administration of CDX-085 resulted in significantly lower total cholesterol levels (528±68 mg/dL vs. 550±67 mg/dL vs. 602±80 mg/dL, p=0.047) and aortic arch atherosclerosis (9.0±4.2% vs. 9.8±3.5% vs. 13.2±3.6%, p=0.023) in the 0.4% CDX-085 group compared to the 0.08% CDX-085 and CHOW groups, respectively. In ApoE(-/-) mice, a 72% reduction in triglycerides in the 0.4% CDX-085 group and 50% reduction in the 0.08% CDX-085 groups was noted compared to CHOW group (final levels 17±11 mg/dL vs. 30±15 mg/dL vs. 60±32 mg/dL, respectively, p=0.001).

CONCLUSION

Oral administration of the novel astaxanthin prodrug CDX-085 shows that it distributes among lipoproteins. CDX-085 lowers total cholesterol and aortic arch atherosclerosis in LDLR(-/-) mice and triglyceride levels in ApoE(-/-) mice and shows promise for further evaluation in human studies.

Applications of LDL-apheresis in nephrology

LDL-apheresis (LA) was originally used for familial hyperlipidemia, and then in Japan extended to use for the treatment of patients with peripheral arterial disease (PAD) and nephrotic syndrome due to steroid-resistant focal glomerular sclerosis (FGS). The reason why this treatment is applicable for these disorders is due to the fact that LA exerts its favorable effects beyond the lipid-lowering effect. The main underlying mechanisms, for example, in the case of LA application in patients with PAD are: (1) improvement of hemorheology, (2) improvement of endothelial dysfunction, (3) elevations of serum levels of NO and bradykinin, (4) increase in serum levels of vascular endothelial growth factor, and (5) reduction of adhesion molecules on monocytes. Furthermore, we have reported that LA could have anti-inflammatory effects because LA reduces serum levels of P-selectin, which is known to play an important role in the development of atherosclerosis as well as a reduction of serum C-reactive protein levels as standard biomarker of atherosclerosis. Massive proteinuria is also an important challenge in nephrology. The possible mechanisms besides removal of toxic lipids are the reduction of the vasoconstrictive prostanoid and thromboxane A2 (TXA2) and an improvement in macrophage function evidenced by a significant amelioration of interleukin-8 production by lipopolysaccharide-stimulated peripheral blood mononuclear cells. It is intriguing to note that in terms of pharmacodynamics, LA improves steroid and cyclosporine uptake into lymphocytes. Although there are no randomized controlled trials, it is clear that LA has various effects beyond lowering lipids. Making the device more concise and changing it into a whole blood adsorption type, we need to collect more clinical cases and to study the underlying mechanisms further.

Efficacy of low-density lipoprotein apheresis in patients with peripheral arterial occlusive disease undergoing hemodialysis treatment

BACKGROUND

Low-density lipoprotein (LDL) apheresis is effective in the treatment of peripheral arterial occlusive disease (PAOD). In the present study, we attempted to determine whether LDL apheresis is effective even for PAOD patients undergoing hemodialysis, who tend to be refractory to any treatment, and if so, to determine the mechanism of its efficacy.

METHODS

Serum levels of lipids and vascular growth factors, leg symptom, and endothelium-dependent vasodilation were investigated before and after 10 sessions of LDL apheresis in 11 PAOD patients undergoing hemodialysis.

RESULTS

Serum levels of total cholesterol, LDL cholesterol, and triglyceride exhibited drastic reduction, which completely disappeared 4 weeks after the final apheresis. Resting leg pain was improved in 6 cases even 4 weeks after final apheresis. Endothelium-dependent vasodilation was significantly increased 4 weeks after final apheresis (1.6 +/- 0.6 to 4.7 +/- 1.0%, p < 0.05). Levels of vascular growth factors, hepatocyte growth factor and vascular endothelial growth factor were not changed during treatment.

CONCLUSIONS

These findings suggested that LDL apheresis is effective even in PAOD patients undergoing hemodialysis. Our findings suggest that its mechanisms of efficacy include improvement of vascular endothelial dysfunction, in addition to drastic but acute reduction of lipid levels. Since PAOD patients undergoing hemodialysis tend to be resistant to any treatment and are at high risk for lower-extremity amputation, LDL apheresis could be a useful strategy for treatment of them.

Acarbose ameliorates atherogenecity of low-density lipoprotein in patients with impaired glucose tolerance

Acarbose, an alpha-glucosidase inhibitor, is administered to control blood glucose levels. The drug also reduces the risk of cardiovascular disease, but the underlying mechanism is still to be elucidated. We therefore hypothesized that treatment with acarbose ameliorates the atherogenecity of low-density lipoprotein (LDL), a key molecule in atherogenesis. Patients with impaired glucose tolerance were or were not treated with acarbose (acarbose-treated group [n = 20] and control group [n = 20], respectively) for 3 months under dietary therapy. The oxidative susceptibility of LDL was determined by measuring lag time for the formation of dienes in the presence of CuSO(4). The lag time was significantly longer in the acarbose-treated group than in the control group before treatment. Moreover, the density gradient lipoprotein separation and disk polyacrylamide gel electrophoresis analyses showed that acarbose reduced the amount of small dense LDL, a more atherogenic and oxidatively susceptible form of LDL. We also found that the fatty acid composition of LDL changed after the treatment: polyunsaturated (omega-3) fatty acid, a beneficial substance for preventing cardiovascular disease, was significantly increased, whereas saturated fatty acids and triglyceride were decreased in the LDL of the acarbose-treated group. The present findings suggest that acarbose treatment reduces the risk of cardiovascular diseases by ameliorating the atherogenecity of LDL.

In vivo metabolism of LDL subfractions in patients with heterozygous FH on statin therapy

LDL can be subfractionated into buoyant (1.020-1.029 g/ml(-1)), intermediate (1.030-1.040 g/ml(-1)), and dense (1.041-1.066 g/ml(-1)) LDLs. We studied the rebound of these LDL-subfractions after LDL apheresis in seven patients with heterozygous familial hypercholesterolemia (FH) regularly treated by apheresis (58 +/- 9 years, LDL-cholesterol = 342 +/- 87 mg/dl(-1), triglycerides = 109 +/- 39 mg/dl(-1)) and high-dose statins. Apolipoprotein B (apoB) concentrations were measured in LDL subfractions immediately after and on days 1, 2, 3, 5, and 7 after apheresis. Compartmental models were developed to test three hypotheses: 1) that dense LDLs are derived from the delipidation of buoyant and intermediate LDLs (model A); 2) that dense LDLs are generated directly from LDL-precursors (model B); or 3) that a model combining both pathways (model C) is necessary to describe the metabolism of dense LDLs. In all models, it was assumed that apoB production and fractional catabolic rate (FCR) did not change with apheresis. Apheresis decreased buoyant, intermediate, and dense LDL-apoB by 60 +/- 12%, 67 +/- 5%, and 69 +/- 11%, respectively. Models B and C, but not model A, described the rebound data. The model with the greatest biological plausibility (model C) was used to estimate metabolic parameters. FCR was 1.05 +/- 0.86 d(-1), 0.48 +/- 0.11 d(-1), and 0.69 +/- 0.24 d(-1) for buoyant, intermediate, and dense LDLs, respectively. Dense LDL production was 17.3 +/- 0.2 mg/kg(-1)/d(-1), 58% of which was derived directly from LDL precursors (VLDL, IDL, or direct secretion), while 42% was derived from buoyant and intermediate LDLs. Thus, our data indicate that in statin-treated patients with heterozygous FH dense LDLs originate from two sources. Whether this is also valid in other metabolic situations (with predominant small, dense LDLs) remains to be determined.

Ascorbate Supplement Reduces Oxidative Stress in Dyslipidemic Patients Undergoing Apheresis

OBJECTIVE

The effect of ascorbate treatment on apheresis-induced oxidative stress in uremic and dyslipidemic patients was evaluated.

METHODS AND RESULTS

We developed a chemiluminescence-emission spectrum and high-performance liquid chromatography analysis to assess the effect of ascorbate supplement on plasma reactive oxygen species (ROS) scavenging activity and oxidized lipid/protein production in hyperlipidemic and uremic patients undergoing apheresis. Apheresis was efficient in reduction of atherogenic lipoproteins, complement, fibrinogen, soluble intercellular adhesion molecule-1, and oxidative parameters including phosphatidylcholine hydroperoxide (PCOOH), malonaldehyde, methylguanidine, and diotyrosine. Apheresis itself, however, activated leukocytes to increase ROS activity and reduced the plasma ROS scavenging activity. Ascorbate administration selectively diminished apheresis-enhanced H2O2 and inflammatory mediators such as tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein-1. Chronically dyslipidemic and uremic patients undergoing biweekly apheresis plus ascorbate treatment had lower levels of C-reactive protein and PCOOH than did those without ascorbate treatment during a 6-month follow-up study period.

CONCLUSIONS

We demonstrate that apheresis with ascorbate treatment provides a therapeutic potential in reducing atherosclerotic risk via inhibition of H2O2-induced oxidative stress in patients with uremia or dyslipidemia.

Improvement of endothelium-dependent coronary vasodilation after a single LDL apheresis in patients with hypercholesterolemia

The purpose of this study was to determine whether a single LDL apheresis would improve impaired endothelium-dependent dilation of the coronary artery in patients with hypercholesterolemia. Hypercholesterolemia is associated with impaired endothelial function, and human studies using cholesterol-lowering drugs indicate that endothelial function in the coronary arteries improves with reduction of serum LDL cholesterol over 6 to 12 months. The internal diameter of the left coronary artery and the coronary blood flow were measured by intracoronary Doppler-wire measurement and quantitative angiography before and immediately after a single LDL apheresis in a population of 15 patients with familial hypercholesterolemia. Endothelium-dependent vasodilation was assessed by intracoronary infusion of acetylcholine (1, 10, and 50 microg/min), and endothelium-independent vasodilation was assessed by intracoronary bolus infusion of isosorbide dinitrate (2.5 mg) or papaverine (10 mg). A single 3-hour LDL apheresis reduced serum LDL cholesterol by an average of 86.6 +/- 1.7%. After the LDL apheresis, the changes in the coronary artery diameter and coronary blood flow in response to an infusion of 50 microg/min of acetylcholine increased significantly compared to the pre-apheresis values (from -19.7 +/- 4.8 to -2.9 +/- 3.0% [P < 0.01] and from 80.7 +/- 27.6 to 155.3 +/- 23.5% [P < 0.01], respectively). The LDL apheresis did not significantly change the response of either parameter to infusion with isosorbide dinitrate or papaverine. The endothelial function of the epicardial coronary artery and the coronary microvasculature improved in hypercholesterolemic patients after only a single LDL apheresis, a procedure that markedly reduces the serum level of LDL cholesterol.

Effect of low-density lipoprotein apheresis on plasma endothelin-1 levels in diabetic hemodialysis patients with arteriosclerosis obliterans

Endothelin (ET)-1 has been implicated in the pathogenesis of diabetes, arteriosclerosis, and chronic renal failure. We studied whether low-density lipoprotein (LDL) apheresis alters plasma ET-1 levels in diabetic hemodialysis patients with arteriosclerosis obliterans (ASO). Plasma ET-1 levels were measured in 30 healthy control subjects (Group A), 30 diabetes patients without ASO (Group B), 20 diabetes patients with ASO (Group C), 20 diabetes patients without ASO who were undergoing hemodialysis (Group D), and 6 diabetes patients with ASO who were undergoing hemodialysis (Group E). Hemodialysis patients were dialyzed three times weekly with a bicarbonate dialysate. Six diabetic hemodialysis patients with ASO underwent LDL apheresis once weekly for 10 weeks, and the change in plasma ET-1 levels due to LDL apheresis was measured. LDL apheresis resulted in a statistically significant decrease in levels of total cholesterol and LDL cholesterol. In addition, LDL apheresis improved clinical symptoms in all patients. Plasma ET-1 levels in Group E (15.0+/-1.9 pg/ml) were significantly higher than those in Groups A (1.0+/-0.6 pg/ml, P<.001), B (1.3+/-0.5 pg/ml, P<.001), C (5.6+/-1.0 pg/ml, P<.001), and D (10.4+/-1.6 pg/ml, P<.01). Plasma ET-1 levels decreased progressively and significantly after a single LDL apheresis began (9.4+/-1.0 pg/ml after 60 min, P<.001, and 6.0+/-1.0 pg/ml after 120 min, P<.001). These data suggest that ET-1 may be associated with arteriosclerosis and that LDL apheresis enhances peripheral microcirculation in part by reducing the production of ET-1 in diabetic hemodialysis patients with ASO.

Changes in oxidative stress and microcirculation by low-density lipoprotein apheresis

Low-density lipoprotein apheresis (LDLA) leads to an improvement of microcirculation during the very early stages of treatment, and continued treatment may produce antiatherogenic effects in patients with peripheral arterial disease (PAD). Suppression of oxidative stress, improvement of endothelial functions and alteration in the action of vasoactive compounds may occur with the improvement of the rheological property of blood as a result of aggressive removal of atherogenic factors including LDL, possibly resulting in the suppression of development of atherosclerosis. As these effects of LDLA may ameliorate not only PAD but also ischemia in other organs, it is suggested that repeated LDLA prevents the progression of atherosclerotic diseases and probably improves the long-term prognosis of patients with PAD.

Beneficial effect of aggressive low-density lipoprotein apheresis in a familial hypercholesterolemic patient with severe diabetic scleredema

We present a 59-year-old woman with severe diabetic scleredema (DS) associated with heterozygous familial hypercholesterolemia (FH). She had been treated with drugs to lower blood glucose, with insulin for diabetes mellitus (DM), and with low-density lipoprotein (LDL) apheresis therapy monthly or every 2 weeks in addition to drugs to lower serum lipids for FH. However, her scleredema had not improved. After we had tried weekly LDL apheresis therapy for a period of 3 years to treat her hyperlipidemia, the levels of her serum lipids were reduced to normal ranges, and scleredema in her nape improved. We also demonstrated the histopathological improvement in dermis of her cervical skin. We conclude that weekly LDL apheresis therapy is effective for diabetic scleredema that is resistant to conventional treatments.

Serum lipid metabolism abnormalities and change in lipoprotein contents in patients with advanced-stage renal disease

BACKGROUND

Arteriosclerosis is the major cause of death in patients with chronic renal failure. There is much interest in the lipid metabolism of patients treated with hemodialysis.

METHODS

We analyzed low-density lipoproteins (LDL) and high-density lipoproteins (HDL) in chronic renal failure (CRF) patients according to patients on hemodialysis (HD), patients with diabetic nephropathy before initiation of dialysis (DN), and patients with chronic glomerulonephritis in the conservative stage (CGN); and compared the lipid metabolic abnormalities in patients on hemodialysis and those not yet on hemodialysis. We also analyzed the qualitative abnormalities of LDL and HDL and their relationship with the pathological stages.

RESULTS

Electrophoretic patterns identified small LDL particles and small HDL particles in the three groups, and the degree of denaturation was more enhanced in CRF patients in the conservative stage than in HD patients. For LDL susceptibility to oxidation LDL (oxLDL) by addition of Cu(2+), the lag time was approximately 57 min in healthy controls and CGN patients, but was prolonged to approximately 75 min in HD and DN patients. For HDL susceptibility to oxidation HDL (oxHDL), HD, DN and CGN patients showed lag times shorter than those found in healthy control subjects. These results showed that LDL and HDL in the serum of CRF patients were in a state of enhanced susceptibility to oxidative modification. In Western blot analysis using anti-human-denatured LDL and anti-human-oxidized HDL monoclonal antibodies, bands of low molecular oxLDL at 150-197 kDa were detected in all CRF patients, with marked tailing in CGN patients. Similarly, bands of small oxHDL particles at 110 and 120 kDa were found in HD, DN and CGN patients.

CONCLUSIONS

Oxidative modification of both LDL and HDL occurs in patients with advanced CRF resulting in small lipoproteins. Increased production of oxLDL and oxHDL is the main cause of lipid metabolic abnormality in CRF patients.

Low-density lipoprotein apheresis using the Liposorber system: features of the system and clinical benefits

LDL apheresis using the Liposorber system is indicated for use to remove selectively LDL from the plasma of hypercholesterolemic patients for whom diet and maximum cholesterol-lowering drug therapy have been ineffective or not tolerated. The dextran sulfate immobilized to porous cellulose beads is contained in the adsorption column as the adsorbent. The dextran sulfate has a structure similar to that of the LDL receptor and seems to act as a type of pseudoreceptor for LDL. There have been reported a number of clinical benefits using the Liposorber system for drug refractory hypercholesterolemic patients. Among them, the improvement of endothelial cell function of coronary and brachial arteries by a single treatment is the focus of the world's attention. Moreover, it is also noteworthy that LDL apheresis reduced the incidence of the cardiac events by 70% compared to drug therapy alone. In addition to the clinical benefits of the Liposorber system on familial hypercholesterolemia (FH), the preliminary data suggest that LDL apheresis may improve arteriosclerosis obliterans (ASO) of the lower extremities and focal glomerular sclerosis (FGS).