Extracorporeal Removal of Lipids by Dextran Sulfate Cellulose Adsorption

Abstract: Extracorporeal removal of low–density lipoprotein (LDL) cholesterol by dextran sulfate adsorption is indicated in patients with diet and drug resistant hypercholesterolemia to prevent or to regress coronary heart disease. Plasma separation is the first step in the process, followed by adsorption of LDL cholesterol and lipoprotein (a) (Lp[aJ) to negatively charged dextran sulfate co–valently bound to cellulose beads. The reduction per treatment in LDL cholesterol is 65–75% and in Lp(a) 40–60%. In most patients one treatment per week is sufficient to reduce mean LDL to 100–150 mg/dl. Minor side effects occur in 2–6% of treatments. Major side effects are rare. In uncontrolled studies long–term treatment was associated with inhibition of progression and induction of regression of coronary artery disease. LDL apheresis by dextran sulfate may increase blood perfusion of some tissues, and preliminary results indicate a beneficial effect on therapy resistant nephrotic syndrome with hypercholesterolemia.     

Plasma lipoprotein (a) levels in children with minimal lesion nephrotic syndrome

We studied the plasma lipoprotein (a)[Lp(a)] levels in 31 children with minimal lesion nephrotic syndrome (MLNS) in both stages of acute NS and remission.The mean Lp(a) levels in acute NS were significantly higher than those of the controls. The Lp(a) levels in remission were significantly lower than the Lp(a) levels in acute NS. In addition, the Lp(a) levels in remission were not significantly different from those of the controls. However, there were 5 patients whose Lp(a) levels remained higher than 30 mg/dl (the generally accepted limit for cardiovascular risk) after remission. Two of these 5 patients had Lp(a) levels greater than 40 mg/dl. In these patients apoprotein (a) [apo(a)] phenotypes were of lower molecular weight than those of the other 23 patients whose apo(a) phenotypes were examined. Additional episodes of relapse may put the patient with sustained elevated Lp(a) levels at significant risk for the development of cardiovascular disease in the long term. Received: 17 November 1998 / Revised: 9 March 1999 / Accepted: 16 March 1999     

Treatment of Homozygous Familial Hypercholesterolemia with Low Density Lipoprotein Apheresis: A 4 Year Follow-Up Study

Abstract: Hypercholesterolemia and elevated lipoprotein (a) (Lp[a]) levels are considered to be risk factors for the development and progression of premature atherosclerosis. The purpose of our report is to describe the effects of low density lipoprotein (LDL) apheresis (Liposorber system, Kanegafuchi Chemical Industrial Company LTD, Osaka, Japan) on serum lipoprotein concentrations and the clinical status in 2 male patients with homozygous familial hypercholesterolemia. Compared with pretreatment values, the posttreatment concentrations of total cholesterol, LDL cholesterol, and Lp(a) were significantly reduced by 50–60% (p < 0.0001). The concentration of high density lipoprotein (HDL) cholesterol was slightly affected. After one treatment session, LDL cholesterol and Lp(a) were decreased on average by 65% and then increased to reach about 70–75% of the pretreatment values before the next session. Prior to the treatment with LDL apheresis, each patient had suffered one myocardial infarction and had had 2 coronary angiographies. After treatment with LDL apheresis, neither cardiac complaints nor myocardial infarction were observed. The xanthomas were much decreased during the treatment or disappeared. We conclude that LDL apheresis can be continued safely and without major technical problems for several years. Apheresis effectively lowers the serum levels of total and LDL cholesterol. Furthermore, it reduces Lp(a), which is not influenced by lipid-lowering drugs. The reduction of LDL cholesterol and Lp(a) may delay the progression of the atherosclerotic process, thereby helping to reduce the risk of new episodes of coronary heart disease and thus extending the life expectancy in these patients.     

Low–Density Lipoprotein Apheresis in the Treatment of Two Patients with Coronary Heart Disease and Extremely Elevated Lipoprotein (a) Levels

Abstract: Hyperlipidemia and elevated lipoprotein (a) (Lp[a]) levels have been linked to the development and progression of premature atherosclerosis. Our study concerned 2 white male patients (aged 36 and 42 years) with heterozygous familial hypercholesterolemia and extremely elevated Lp(a) concentrations that were resistant to diet regimens and lipid–lowering drugs. The patients were treated with low–density lipoprotein (LDL) apheresis for 59 months (Liposorber system, Kaneka, Japan) and 19 months (immunoadsorption system, special Lp(a) columns; Lipopak; Pocard, Russia), respectively. The concentration of Lp(a) decreased on average by 50%, total cholesterol by 27%, LDL cholesterol by 41%, triglycerides by 43%, and fibrinogen by 16%. High–density lipoprotein (HDL) cholesterol increased by approximately 4%. Before treatment with LDL apheresis, each patient had suffered 3 myocardial infarctions, and had had 4 and 6 coronary angiographies with 2 and 4 percutaneous transluminal angioplasties (PTCAs), respectively. Since treatment with LDL apheresis, no myocardial infarctions or cardiac complaints were observed. In the course of treatment, both patients reported an increased performance. Available data suggest that LDL apheresis may be effective in the treatment of patients, the only risk factor for premature atherosclerosis being extremely elevated Lp(a) concentrations.     

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

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

Pentanucleotide repeat and size polymorphisms in the apolipoprotein(a) gene are associated with the lipoprotein(a) concentration in chronic hemodialysis patients

The elevation of serum or plasma lipoprotein(a) [Lp(a)] levels is regarded as an independent risk factor for cardiovascular disease, and many previous reports demonstrated that Lp(a) levels in hemodialysis patients were significantly higher than in controls. The purpose of this study was to investigate the effect of a pentanucleotide repeat polymorphism [(TTTTA)n] in the 5'-flanking region of the apolipoprotein(a) [apo(a)] gene and of a size polymorphism of apo(a) for elevated Lp(a) concentrations observed in chronic hemodialysis patients. We studied 172 patients on chronic hemodialysis and 199 healthy adults. For analysis of the pentanucleotide repeat polymorphism, polymerase chain reaction products were loaded on polyacrylamide gel for electrophoresis. apo(a) size phenotyping was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The median level of Lp(a) in the patients was 14.2 mg/dl which was significantly higher than that in controls (12.0 mg/dl; p < 0.05). In the genotype of (TTTTA)8/8, the median Lp(a) level in the patients (15.9 mg/dl) was significantly higher than that in controls (13.0 mg/dl; p < 0.05). In the genotype of (TTTTA)8/8 with large-sized apo(a) isoforms (A16-A25), the patients had significantly higher Lp(a) levels than the controls (p < 0.05). In conclusion, increased Lp(a) levels in chronic hemodialysis patients were mainly attributed to the combination of eight repeats of the pentanucleotide polymorphism and large-sized isoforms of apo(a).     

Lipoprotein(a)-associated atherothrombotic risk in hemodialysis patients

BACKGROUND: Hemodialysis patients show a considerably higher risk of atherothrombotic disease than the general population. We investigated both lipoprotein(a) [Lp(a)] plasma levels and apolipoprotein(a) [apo(a)] phenotypes in relation to occurrence of atherothrombotic events in hemodialysis patients compared with subjects showing a normal kidney function. Methods: Lp(a) levels and apo(a) isoforms were determined in 118 hemodialysis patients, including 59 with prior atherothrombotic events, and in 182 subjects with normal creatinine clearance, including 82 who experienced a prior atherothrombotic event. Results: Lp(a) levels in hemodialysis patients (median; 20 mg/dl) were higher (p < 0.01) than in age- and sex-matched subjects with normal renal function without a history of atherothrombosis (11.3 mg/dl). Among hemodialysis patients, median Lp(a) levels were higher in subjects with than in those without prior atherothrombosis (34 vs. 15 mg/dl, p < 0.05). In hemodialysis patients and in subjects without nephropathy, the percentage of low-molecular-weight apo(a) phenotypes were significantly higher in patients with than in those without a history of prior atherothrombotic events (56.9% vs. 33.9%, p < 0.05; 62.2% vs. 25%, p < 0.00001,respectively). Stepwise regression analysis indicated that the presence of at least one apo(a) isoform of low molecular weight was an independent predictor of atherothrombosis in hemodialysis patients (p < 0.05). Conclusions: Elevated Lp(a) plasma levels appear to be associated with atherothrombosis, independent of their origin due to genetic factors or related to the impaired kidney function. Low-molecular-weight apo(a) isoforms are reliable genetic markers of atherothrombosis both in patients with impaired kidney function and in subjects without nephropathy.     

LDL Apheresis: A Novel Technique (LIPOCOLLECT 200)

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

Lipoprotein(a) serum concentrations and apolipoprotein(a) phenotypes in mild and moderate renal failure

High lipoprotein(a) (Lp(a)) serum concentrations and the underlying apolipoprotein(a) (apo(a)) phenotypes are risk factors for cardiovascular disease in the general population as well as in patients with renal disease. Lp(a) concentrations are markedly elevated in patients with end-stage renal disease. However, nothing is known about the changes of Lp(a) depending on apo(a) size polymorphism in the earliest stages of renal impairment. In this study, GFR was measured by iohexol technique in 227 non-nephrotic patients with different degrees of renal impairment and was then correlated with Lp(a) serum concentrations stratified according to low (LMW) and high (HMW) molecular weight apo(a) phenotypes. Lp(a) increased significantly with decreasing GFR. Such an increase was dependent on apo(a) phenotype. Only renal patients with HMW apo(a) phenotypes expressed higher median Lp(a) concentrations, i.e., 6.2 mg/dl at GFR >90 ml/min per 1.73 m2, 14.2 at GFR 45 to 90 ml/min per 1.73 m2, and 18.0 mg/dl at GFR <45 ml/min per 1.73 m2. These values were markedly different when compared with apo(a) phenotype-matched control subjects who had a median level of 4.4 mg/dl (ANOVA, linear relationship, P < 0.001). In contrast, no significant differences were observed at different stages of renal function in patients with LMW apo(a) phenotypes when compared with phenotype-matched control subjects. The elevation of Lp(a) was independent of the type of primary renal disease and was not related to the concentration of C-reactive protein. Multiple linear regression analysis found that the apo(a) phenotype and GFR were significantly associated with Lp(a) levels. Non-nephrotic-range proteinuria modified the association between GFR and Lp(a) levels. In summary, an increase of Lp(a) concentrations, compared with apo(a) phenotype-matched control subjects, is seen in non-nephrotic patients with primary renal disease even in the earliest stage when GFR is not yet subnormal. This change is found only in subjects with HMW apo(a) phenotypes, however.     

H.E.L.P. Apheresis Therapy in the Treatment of Severe Hypercholesterolemia: 10 Years of Clinical Experience

Abstract: In collaboration with B. Braun Melsungen AG, Germany, we were able to develop the heparin–mediated extracorporeal low–density lipoprotein (LDL) fibrinogen precipitation (H.E.L.P.) system and to introduce it into clinical use. The H.E.L.P. apheresis system is the most potent technique to reduce at the same time LDL, lipoprotein (a) (Lp[a]), and fibrinogen plasma concentrations if the physiological clearing mechanisms are insufficient and if diet and drugs fail to achieve a target concentration of 100 mg/dl LDL–cholesterol or lower, required for secondary prevention of coronary heart disease. The H.E.L.P. LDL apheresis system also improves plasma viscosity and microcirculation efficiently. The clinical experience with the H.E.L.P. system has proved its clinical utility; regression of coronary heart disease occurs, a decrease in events of coronary heart disease takes place, and acute as well as chronic impairment of microcirculation shows a remarkable improvement with H.E.L.P. therapy. For the future, the availability of this safe and efficient apheresis technique may help many patients who previously could not be treated adequately     

Extracorporeal treatment of hypercholesterolaemia

Extracorporeal removal of LDL cholesterol (LDL apheresis) hasbeen carried out in patients with diet- and drug-resistant hypercholesterolaemiato prevent or to reduce coronary heart disease. Plasma separationis the first step in all five LDL-apheresis methods presentlyavailable. Plain plasma exchange and double-membrane filtrationare unselective and remove HDL cholesterol and plasma proteins.Adsorption of LDL to dextran sulphate, to LDL antibodies, orprecipitation of LDL by heparin at low pH are more selective.With all methods LDL cholesterol reduction per treatment is60–70%. In most patients one treatment per week is sufficientto reduce mean LDL to 100–150 mg/dl. Minor side-effectsoccur in 10±5% of treatments. Major side-effects arerare. Long-term LDL apheresis increased survival in patientswith homozygous familial hypercholesterolaemia. In heterozygousfamilial hypercholesterolaemia controlled studies regardingsurvival are not available. Uncontrolled trials indicate regressionof coronary artery disease in heterozygotes with drug- and diet-resistantLDL cholesterol > 200 mg/dl. Hence, LDL apheresis is indicatedin all patients with homozygous familial hypercholesterolaemia.LDL apheresis in heterozygous familial hypercholesterolaemiashould be restricted to patients with diet- and drug-resistantLDL cholesterol >200 mg/dl with coronary heart disease and/orother atherosclerotic vascular lesion.     

Does Regular Lipid Apheresis in Patients With Isolated Elevated Lipoprotein(a) Levels Reduce the Incidence of Cardiovascular Events?

Elevated lipoprotein(a) (Lp(a)) is known as an independent risk factor for atherosclerosis and cardiovascular events. Regular lipid apheresis decreases elevated Lp(a) concentrations. However, there is a lack of reliable data regarding the effect of lipid apheresis on cardiovascular endpoints. To assess the effects of apheresis, we compared the occurrence of cardiovascular events in 37 patients treated regularly with lipid apheresis at the time periods of preinitiation of apheresis and during apheresis treatment. A retrospective analysis of 37 patients (35 men and two women; aged 58 years ± 11 [mean ± standard deviation]; body mass index 26 kg/m² ± 3; low‐density lipoprotein (LDL)‐cholesterol before apheresis 84 mg/dL ± 21; Lp(a) before apheresis 112 mg/dL ± 34) treated regularly with lipid apheresis was performed. Patients' medical records were screened for cardiovascular events at the preapheresis and during apheresis periods. Apheresis led to a significant reduction of lipid levels (LDL cholesterol ?60%; Lp(a) –68%) measured after apheresis. The event‐free survival rate after 1 year in the preapheresis period was 38% (22–54%, 95% confidence interval [CI]) vs. 75% (61–89%, 95% CI) in the during‐apheresis period with a statistically significant difference (P < 0.0001). Apheresis seems to lower the progression of atherosclerosis leading to a reduced number of cardiovascular events in hyperlipoproteinemia(a). Because prospective and controlled trials are lacking, the therapeutic effectiveness of lipid apheresis can only be estimated.     

Serum lipoprotein (a) levels in 'normal' individuals, those with familial hypercholesterolaemia, and those with coronary artery disease

Lipoprotein (Lp)(a) represents a quantitative genetic trait. Elevated Lp(a) levels (greater than 25-30 mg/dl) have been linked epidemiologically to cardiovascular disease. A high Lp(a) level seems to be an additional independent risk factor for the accelerated progression of atherosclerosis, although the exact mechanism involved is not yet known. Individuals with familial hypercholesterolaemia (FH) have also been shown to have elevated Lp(a) levels, but again the reason for this is unclear. A preliminary investigation of serum Lp(a) levels in 30 apparently healthy individuals, 38 FH patients and 34 individuals with coronary artery disease (CAD) was conducted. Lp(a) levels were distributed over a wide range, varying from barely detectable to above 84.0 mg/dl. A greater incidence of elevated Lp(a) levels (greater than 30 mg/dl) was found in both the FH group (71%) and the CAD group (41%) compared with 'normal' individuals (30%). Analysis of the circulating Lp(a) level may be useful in determining an individual's long-term risk for cardiovascular disease.     

Plasma and Lp(a)-associated PAF-acetylhydrolase activity in uremic patients undergoing different dialysis procedures

Plasma and Lp(a)-associated PAF-acetylhydrolase activity in uremic patients undergoing different dialysis procedures. BACKGROUND: Platelet-activating factor (PAF) is a potent inflammatory mediator associated with several physiopathological conditions, including renal diseases. PAF is degraded to the inactive metabolite lyso-PAF by PAF-acetylhydrolase (PAF-AH), which is considered as a potent anti-inflammatory and anti-atherogenic enzyme associated with lipoproteins. In this study, we evaluated the plasma- and lipoprotein(a) [Lp(a)]-associated PAF-AH activity in relationship to plasma lipid parameters and Lp(a) isoform size in patients with mild/moderate chronic renal failure (CRF), as well as in hemodialysis (HD) and chronic ambulatory peritoneal dialysis (CAPD) patients. METHODS: We studied 74 patients undergoing maintenance HD, 44 patients undergoing CAPD, 56 patients with mild/moderate CRF, and 98 healthy subjects whose lipid profile, as well as plasma and high-density lipoprotein (HDL)-associated PAF-AH activity, was determined. Moreover, the effect of Lp(a) plasma levels on the distribution of PAF-AH among plasma lipoproteins, as well as the specific activity and kinetic properties of PAF-AH on two different Lp(a) isoforms, was measured in each studied group. RESULTS: The plasma PAF-AH activity in all studied groups was significantly higher than in controls, and the increase was more profound in CAPD patients. The HDL-associated PAF-AH activity, expressed per milliliter of plasma, was similar among all studied groups; however, when it was expressed as either per milligrams of HDL cholesterol or per milligrams of plasma apolipoprotein (apo) AI, the PAF-AH activity was significantly higher in all patient groups compared with controls. All patient groups had significantly elevated plasma Lp(a) levels, which altered the distribution of PAF-AH among the plasma lipoproteins compared with that observed in subjects with very low plasma Lp(a) levels (<8 mg/dl). Additionally, in each studied group, the specific activity as well as the apparent Km and Vmax values of the 19K4 apo(a) isoform were significantly higher (P < 0.01) compared with the values of the 23K4 isoform. However, the specific activity, as well as the Km and Vmax values on either the 19K4 apo(a) isoform or the 23K4 isoform, was significantly higher in CAPD patients compared with the other three groups. CONCLUSIONS: Plasma PAF-AH activity is increased in uremic patients. This elevation is more profound in CAPD patients, who also exhibit a more atherogenic lipid profile and more pronounced alterations in the specific activity and the kinetic constants of Lp(a)-associated PAF-AH.     

A study of clinical significance of Lp[a] lipoprotein in patients with chronic renal failure treated by hemodialysis

Lipoprotein [a] (Lp[a]) is known to show high values in patients with ischemic heart disease (IHD). In the present study attempts were made to determine Lp[a] levels and to investigate the association of Lp[a] and other atherosclerotic risk factors in patients with chronic renal failure treated by hemodialysis. Lp[a] concentrations were measured in 30 hemodialysis patients in the age range 34 to 77 years. Mean (+/- SD) levels of serum Lp[a] were not elevated in the hemodialysis patients compared to controls (19.3 +/- 18.0 mg/dl vs. 18.3 +/- 10.4 mg/dl, respectively). We found no statistically significant correlation of Lp[a] with either cholesterol, triglycerides, HDL-C or apoproteins. However, compared with controls, more than fivefold as many of those hemodialysis patients had high risk (greater than 30 mg/dl) concentrations of Lp[a]. Lp[a] tended to increase in hemodialysis patients with diabetes mellitus and/or ischemic heart disease. In patients with high levels of Lp[a] (greater than 30 mg/dl), Lp[a] tended to correlate positively with cholesterol, LDL-, HDL-C, apo B or apo B/AI. Incidence of IHD was also elevated in these patients. Along with other known risk factors such as hyperlipidemia and hypertension, an increased concentration of Lp[a] may play an important role in accelerating development of atherosclerosis in this condition.     

Plasma levels of lipoprotein (a) do not predict progression of human chronic renal failure

Chronic renal failure is frequently accompanied by elevatedplasma levels of lipoprotein (a) [Lp(a)] Elevated Lp(a) levelshave been proposed to contribute not only to increased riskof atherosclerotic and thrombotic complications but also tothe progression of renal insufficiency. To investigate whetherhigher Lp(a) plasma concentrations are associated with an acceleratedrateof progression of renal insufficiency, we have correlated baselineplasma concentrations of Lp(a) with the progressive declineof renal function in an observational study of human chronicrenal disease. Forty-nine non-diabetic patients (40 men, ninewomen) were studied as part of an observational study of patientswith moderately advanced renal insufficiency. The average follow-uptime of the patient population was 3.1 years, and the mean rateof decline in glomer ular filtration rate (⁵¹Cr-EDTA clearance)was –2.8 (SD 4.1) ml/min/1.73 m² The mean plasma concentrationof Lp(a) at the beginning of the study was 19.2 (SD 18.6) mg/100ml with a median value of 12.2 mg/100 ml. There was no associationbetween the initial plasma concentration of Lp(a) and the rateof progression as assessed by linear regression analysis. Furthermore,the progression rate in patients with in the highest quartileof the Lp(a) distribution (30 mg/100 ml) did not differ fromthat in patients with lower levels of Lp(a). In contrast, increasedlevels of apolipoprotein (apo) B, low-density lipoprotein (LDL)-cholesterol,and proteinuria were all significantly associated with a morerapid decline in renal function. Based on these results, itwas concluded that elevated plasma levels of Lp(a) are not associatedwith an increased rate of progression of renal insufficiencyin human chronic renal disease. However, the results of thisstudy suggest that other apoB-containing lipoproteins may playa significant role in this process.     

Alteration of the lipid and apolipoprotein contents of lipoprotein (a) in haemodialysis patients

BACKGROUND: To examine the possible alteration in Lp(a) composition, proteinand lipid contents of Lp(a) were determined in 10 haemodialysispatients (HD) matched with 10 controls (C) fox apo(a) phenotypes. METHODS: All subjects (HD and C) had Lp(a) concentrations greater than30 mg/dl (mean±SD : 82.3±41.4 vs 49.3±22.5mg/dl), a concentration which has been determined to be associatedwith an elevated cardiovascular risk. Apo(a)-containing particleswere isolated by immunoaffinity chromatography using a monoclonalanti-apo(a) antibody. RESULTS: The molar concentrations of lipid and protein constituents ofimmunoaffinity isolated Lp(a) were expressed as number of molesper mole of apo(a). Lp(a) from HD patients were significantlyricher in apo Clll (P<0.05) and triglycerides (TG) (P<0.05),compared to those of controls. Molar ratios of apo B, apo E,cholesterol and phospholipids per apo(a)-containing particleswere in the same range in both groups. CONCLUSIONS: Lp(a) from HD patients is characterized by an elevated contentin TG and apo Clll in comparison with those of controls. Furtherstudies are needed to evaluate in HD patients the contributionof changes in Lp(a) composition towards the metabolism of theseparticles.     

Urinary excretion of apo(a) in patients after kidney transplantation

Background: Increased plasma Lipoprotein (a) (Lp(a)) levels are strongly associated with premature cardiovascular disease and stroke. The kidney is purported to play an important role in apo(a) catabolism. Therefore we investigated plasma Lp(a) levels in relation to kidney function and urinary apo(a) excretion. Methods: One hundred and sixteen kidney transplant patients with normal or impaired renal function and 109 age- and sex-matched healthy controls were investigated. Plasma Lp(a) and urinary apo(a) levels were determined by routine laboratory methods. Results: Transplant recipients were found to have significantly elevated total cholesterol and LDL-C values, but equal HDL-C values compared to controls. Plasma Lp(a) values were higher and urinary apo(a) excretion was lower in transplant recipients compared to controls, independent of renal function. When the patient group was subdivided into 'normal' and 'impaired creatinine clearance', only the latter group secreted less apo(a) than normal controls. Conclusion: These data suggest that urinary apo(a) excretion is reduced in transplant recipients with impaired excretory graft function, which may contribute to the elevation of plasma Lp(a) levels in these patients.     

Relationship of non-LDL-bound apo(a), urinary apo(a) fragments and plasma Lp(a) in patients with impaired renal function.

BACKGROUND: Plasma lipoprotein (a) [Lp(a)] has been shown to be a risk factor for atherosclerosis in numerous studies. However, the catabolism of this lipoprotein is not very clear. We and others have shown that Lp(a) is excreted into urine in the form of fragments. Lp(a) has also been shown to exist in a low-density non-lipoprotein (LDL)-bound form. Since Lp(a) is increased in all forms of kidney disease with reduced excretory kidney function and decreased excretion of apo(a) fragments could be partially responsible for this increase, we investigated the relationship of non-LDL-bound apo(a), urinary apo(a) fragments and plasma Lp(a) in patients with impaired renal function. METHODS: Plasma Lp(a), non-LDL-bound apo(a) and urinary apo(a) fragments were measured in 55 kidney disease patients (28 males and 27 females) and matched controls. RESULTS: Plasma Lp(a) and non-LDL-bound apo(a) were increased in patients, whereas urinary apo(a) was decreased, especially in patients with a creatinine clearance < 70 ml/min. There was a significant correlation between plasma Lp(a) and non-LDL-bound apo(a) in patients and controls. CONCLUSION: We conclude that decreased urinary apo(a) excretion could be one possible mechanism of increased plasma Lp(a) and non-LDL-bound apo(a) in patients with decreased kidney function.     

Low-dose prednisolone ameliorates acute renal failure caused by cholesterol crystal embolism

AIMS: The prognosis of renal cholesterol crystal embolism (CCE) is poor. Although various treatments for CCE have been attempted, there is no optimal therapy. We tested the effect of low-dose prednisolone (PS) on CCE-related acute renal failure (ARF). PATIENTS AND METHODS: 7 patients (mean age 69 years) diagnosed with CCE-related ARF were treated with oral PS at 15-20 mg/day for 2-4 weeks, which was then tapered at 5 mg/day over 2-4 weeks, followed by 5 mg/day maintenance dose. Recurrent ARF during PS tapering was treated with a larger dose of PS. RESULTS: Inciting factors were identified in four patients: coronary angiography (n=3) and cerebral angiography (n=1). On admission, serum creatinine (SCr) was 2.1 +/- 0.3 mg/dl (mean +/- SEM). SCr and eosinophil count before treatment were 4.2 +/- 0.4 mg/dl and 682 +/- 73/microl, respectively. PS therapy improved ARF in all cases at week 2 (SCr 3.8 +/- 0.5 mg/dl) parallel to a decrease in eosinophilia (116 +/- 30/microl), and at week 4 (3.1 +/- 0.4 mg/dl and 134 +/- 20/microl, respectively). At last follow-up, renal function was improved or maintained in 5 patients compared with that at week 4 post-treatment. One patient died of lung cancer. Another required LDL apheresis and hemodialysis but died due to CCE-related multi-organ failure. A third patient had recurrent ARF and was re-treated with a larger dose of PS, which resulted in an immediate decrease in SCr. However, the patient developed acute renal dysfunction due to congestive heart failure, and required hemodialysis. CONCLUSIONS: Low-dose PS improved CCE-related ARF, probably through amelioration of inflammatory reaction surrounding affected renal vessels.