Circulating electronegatively charged low-density lipoprotein in patients with angiographically documented coronary artery disease

There is growing experimental evidence to suggest the role of oxidatively modified low-density lipoprotein (LDL) in the initiation and progression of atherosclerosis. The oxidation of lipoprotein moiety causes modification of positively charged lysine residues and results in negative net charge of lipoprotein particles. OBJECTIVE: To measure the amount of circulating electronegatively charged LDL particles (LDL-) in plasma of patients with angiographically documented coronary artery disease (CAD). METHODS: Thirty patients were assigned to the study group (CAD+) and 10 patients to the control group (Ctrl). LDL- was quantitated in homogeneous LDL fractions obtained by ultracentrifugation, using ion exchange high performance liquid chromatography. Plasma lipids were measured using enzymatic kits. RESULTS: The CAD+ group had significantly higher levels of LDL- in the whole LDL fraction (7.66+/-1.92 vs. 5.14+/-0.84%, p=0.0003). Moreover the CAD+ group had significantly higher levels of total cholesterol (255.4+/-35.1 vs. 210.4+/-22.4 mg/dL), LDL cholesterol (154.5+/-26.9 vs. 122.4+/-21.1 mg/dL) and significantly lower levels of high-density lipoprotein (HDL) cholesterol (40.4+/-9.4 vs. 51.0+/-11.5 mg/dL). LDL- remained significantly higher in the CAD+ group after adjustment for total cholesterol, LDL cholesterol and HDL cholesterol (6.3 vs. 5.14% at p=0.0095). There is a trend towards a positive correlation between LDL- levels and LDL cholesterol in the control group (Spearman R=0.55 at p=0.098). CONCLUSIONS: Electronegatively charged LDL appears to be an additional hallmark of coronary artery disease, independently of established lipid risk factors. The trend towards a positive correlation between LDL cholesterol concentration and the level of LDL- in the control group may reflect the susceptibility of LDL cholesterol to autoxidation, Moreover, this may indicate other oxidative mechanisms in coronary artery disease. Nonetheless, further studies assessing the prognostic value of electronegatively charged LDLs are necessary.     

Lipoprotein(a), Cardiovascular Disease,and Contemporary Management

Elevated lipoprotein(a) (Lp[a]) is a causal genetic risk factor for cardiovascular disease. To determine if current evidence supports both screening and treatment for elevated Lp(a) in high-risk patients, an English-language search of PubMed and MEDLINE was conducted. In population studies, there is a continuous association between Lp(a) concentrations and cardiovascular risk, with synergistic effects when low-density lipoprotein (LDL) is also elevated. Candidates for Lp(a) screening include patients with a personal or family history of premature cardiovascular disease, familial hypercholesterolemia, recurrent cardiovascular events, or inadequate LDL cholesterol (LDL-C) responses to statins. Given the comparative strength of clinical evidence, reducing LDL-C to the lowest attainable value with a high-potency statin should be the primary focus of lipid-modifying therapies. If the Lp(a) level is 30 mg/dL or higher in a patient who has the aforementioned characteristics plus residual LDL-C elevations (≥70-100 mg/dL) despite maximum-potency statins or combination statin therapy, the clinician may consider adding niacin (up to 2 g/d). If, after these interventions, the patient has progressive coronary heart disease (CHD) or LDL-C levels of 160-200 mg/dL or higher, LDL apheresis should be contemplated. Although Lp(a) is a major causal risk factor for CHD, no currently available controlled studies have suggested that lowering it through either pharmacotherapy or LDL apheresis specifically and significantly reduces coronary risk. Further research is needed to (1) optimize management in order to reduce CHD risk associated with elevated Lp(a) and (2) determine what other intermediate- or high-risk groups might benefit from Lp(a) screening.     

Relation between lipoprotein (a) and in vitro oxidation of apolipoprotein B-containing lipoproteins

OBJECTIVES: To assess the relationship between lipoprotein (a) [Lp (a)] and lipoprotein oxidation in patients with coronary artery disease (CAD). DESIGN AND METHODS: Oxidation of apolipoprotein (apo)B-containing lipoproteins, vitamin E, carotenoids, lipid-lipoprotein levels were determined in 171 CAD and 70 non-CAD subjects. RESULTS: In CAD patients with Lp (a) concentrations >/= 30 mg/dL; total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), malondialdehyde (MDA), and apo B levels were significantly higher and lag-time and age were significantly lower than those of CAD patients with Lp (a) concentrations < 30 mg/dL. In non-CAD subjects with Lp (a) concentrations >/= 30 mg/dL; TC, LDL-C, and vitamin E levels were significantly higher and lag-time was significantly lower than those of non-CAD subjects with Lp (a) concentrations < 30 mg/dL. In CAD patients, Lp (a) correlated negatively with lag-time and positively with MDA levels. Lp (a) correlated negatively with lag-time and vitamin E levels in non-CAD subjects. CONCLUSIONS: We have shown that plasma apo B-containing lipoproteins of both CAD and non-CAD subjects with Lp (a) levels >/= 30 mg/dL are more susceptible to in vitro oxidative modification than those of subjects with Lp (a) levels < 30 mg/dL. The relationship between Lp (a) and enhanced susceptibility of apo B-containing lipoproteins to oxidation, appears to support routine investigation of Lp (a).     

Evolocumab and lipoprotein apheresis combination therapy may have synergic effects to reduce low‐density lipoprotein cholesterol levels in heterozygous familial hypercholesterolemia: A case report

A 49 years old woman (weight 68 kg, BMI 27.3 kg/m²) with heterozygous familial hypercholesterolemia (HeFH) and multiple statin intolerance with muscle aches and creatine kinase elevation, presented at the Outpatient Lipid Clinic of Verona University Hospital in May 2015. Hypercholesterolemia was firstly diagnosed during adolescence, followed in adulthood by a diagnosis of Cogan's syndrome, a rheumatologic disorder characterized by corneal and inner ear inflammation. No xanthomas, corneal arcus, or vascular bruits were detectable at physical examination. Screening for macrovascular complications did not reveal relevant damages. Ongoing medical therapy included salicylic acid, methylprednisolone, methotrexate, and protonic‐pump inhibitor. In the absence of specific lipid‐lowering therapy, plasma lipid levels at first visit were: total‐cholesterol = 522 mg/dL, LDL‐cholesterol = 434 mg/dL, HDL‐cholesterol = 84 mg/dL, triglycerides = 120 mg/dL, Lp(a) = 13 mg/dL. On December 2015, evolocumab 140 mg sc every 2 weeks was initiated. After a 24‐week treatment, the LDL‐cholesterol levels decreased by an average of 21.2% to 342 ± 22 mg/dL (mean ± SD). On May 2016, LDL‐apheresis (H.E.L.P.system) was started as add‐on therapy. Compared to the average levels obtained during the evolocumab monotherapy period, the LDL‐cholesterol was reduced by 49.4%, thus reaching an inter‐apheresis level (mean ± SD) of 173 ± 37 mg/dL. This report suggests that a combination therapy with evolocumab and lipoprotein‐apheresis may have synergic effects on circulating lipid levels. Its relevance as a highly effective treatment option for hyperlipidemia in HeFH patients warrants further investigation in larger datasets.     

Association between lipoprotein(a) levels, apo(a) isoforms and family history of premature CAD in young Asian Indians

ObjectivesThe purpose of this study was to explore the association between lipoprotein (a) [Lp(a)] levels, apo(a) isoforms and family history of premature coronary artery disease (CAD) in young Asian Indians.Design and methods220 patients (age < 40 years) with angiographic evidence of CAD and 160 age matched healthy controls were enrolled for the study. Thirty one percent of the patients and 17% of the controls had positive family history (PFH) of premature CAD. Plasma Lp(a) levels were determined by ELISA and apo(a) isoform size was determined using high-resolution immunoblotting method.ResultsMedian plasma Lp(a) levels were 2.5 times higher in patients as compared to controls (30 mg/dL vs 12.7 mg/dL; p < 0.05). The patient group having a heterozygous apo(a) isoform pattern showed higher Lp(a) levels as compared to the homozygous group (44.0 ± 38.7 vs 28.0 ± 26.4 mg/dL; p < 0.001). Further low molecular weight apo(a) isoforms (LMW; < 22 KIV repeats) were prevalent among CAD patients with PFH as compared to negative family history (62% vs 14%, p < 0.05) and this group had the highest Lp(a) levels. Stepwise regression analysis showed that Lp(a) levels and not the apo(a) isoform size, entered the model as significant independent predictors of CAD in young Asian Indians.ConclusionsThis study suggests that elevated Lp(a) levels confer genetic predisposition to CAD in young Asian Indians. Thus determination of Lp(a) levels along with other risk factors should be used to assess overall risk for CAD in this ethnic group.     

Increased levels of lipoprotein (a) are related to family risk factors of cardiovascular disease in children and adolescents from Maracaibo, Venezuela

The aims of this study were to determine Lipoprotein (a) [Lp(a)] concentrations in a sample of subjects from Maracaibo, Venezuela, and to determine the relationship of family risk factors for cardiovascular disease and their Lp(a) levels. Two hundred twenty-seven healthy individuals between 5 and 19 years of age of both genders and multiethnic origins were selected. A complete background clinical chart and laboratory test was conducted for each patient to discard cardiovascular diseases and confirm their healthy state. The Lp(a) concentration was determined using the double antibody enzyme-linked immunosorbent assay method. For inferential statistical analysis, one-factor analysis of variance tests and Student t test for independent observations were used according to each case, considered significant when P value was <0.05. No significant differences were observed when evaluating Lp(a) levels according to gender in all ages. Males showed no significant difference in Lp(a) levels between groups, but, in females, a significantly lower level (P < 0.03) in the group 5 to 9 years of age was found. When considering only age, significantly lower levels were observed (P < 0.03) in the 5- to 9-year-old group. When studying family risk factors of cardiovascular diseases, it was found that the group with family risk factors had a significantly higher Lp(a) concentration (P < 0.01) than those without family risk factors, observing that those who had four or more factors exhibited a significantly higher concentration than those with two to three risk factors (30.6 +/- 4.5 mg/dL versus 18.5 +/- 12.2 mg/dL, P < 0.009) and than those with one risk factor (30.6 +/- 4.5 mg/dL versus 21.6 +/- 1.4 mg/dL, P < 0.03). These results emphasize the clusters of family risk factors of cardiovascular disease with higher Lp(a) levels and also indicate that the evaluation of its concentration should be taken as an independent risk factor of atherosclerosis for the population in developmental ages.     

Differing associations of lipid and lipoprotein disturbances with the macrovascular and microvascular complications of type 1 diabetes.

OBJECTIVE: Cardiovascular disease (CVD) is increased in patients with type 1 diabetes, but lipid and lipoprotein patterns remain favorable. In contrast, nephropathy is associated with an adverse distribution. We compared the associations and predictive power of lipid and lipoprotein disturbances with these complications. RESEARCH DESIGN AND METHODS: A nested case-control study from the EURODIAB cohort of 140 case subjects with evidence of at least one complication and 84 control subjects with no complications were analyzed. Conventional and unconventional lipid and lipoprotein fractions, including apolipoprotein (apo)-A1, lipoprotein (Lp)-A1, LpA1/A2, apoB, and LDL particle size were measured centrally. RESULTS: CVD was only associated with increased LDL cholesterol (3.6 vs. 3.0 mmol/l, P = 0.02). In contrast, albuminuria was associated with elevated cholesterol, triglyceride, LDL, and apoB and with diminished LDL particle size. No disturbances in HDL and related lipoproteins were noted. In normoalbuminuric patients, CVD was not associated with any significant changes in lipids. CVD in macroalbuminuric patients was associated with increased triglyceride level (2.37 vs. 1.07 mmol/l, P = 0.001; P = 0.02 for CVD/albuminuria interaction) and LDL cholesterol (5.4 vs. 3.3 mmol/l, P = 0.005; P = 0.004 for interaction). Independent associations were observed for total cholesterol and for LDL particle size and albuminuria. CONCLUSIONS: Abnormalities in lipid and lipoprotein disturbances are more closely related to albuminuria than to CVD in patients with type 1 diabetes. Measurement of conventional parameters provide sufficient risk information. ApoB and LDL particle size offer limited extra information. HDL metabolism remains undisturbed in the presence of complications. These changes reflect associations with glycemic control, which is the key to understanding lipid and lipoprotein disturbances.     

Achieving National Cholesterol Education Program goals for low-density lipoprotein cholesterol in cardiac patients: importance of diet, exercise, weight control, and drug therapy.

OBJECTIVE: To determine how frequently the National Cholesterol Education Program (NCEP) goal of a low-density lipoprotein (LDL) cholesterol level of 100 mg/dL or less is achieved in clinical practice in patients with coronary artery disease and what fraction of patients can achieve this goal without drug therapy. DESIGN: We examined the results of lipid management in 152 consecutive patients who had completed cardiac rehabilitation after an acute coronary event. Patients were randomized to follow-up by specially trained nurses or by preventive cardiologists, and they were not receiving lipid-lowering drugs at the start of the study. MATERIAL AND METHODS: Patients were given aggressive diet and exercise recommendations and lipid-lowering drugs in accordance with NCEP guidelines. Follow-up was continued for a mean of 526 days after the first lipid assessment subsequent to the coronary event. Multiple logistic regression analysis was used to identify independent predictors of a final LDL cholesterol level of 100 mg/dL or less. RESULTS: Of the study group, 39% achieved the NCEP goal LDL cholesterol level of 100 mg/dL or less. Characteristics of the patients with LDL cholesterol levels of 100 mg/dL or less in comparison with those with LDL cholesterol levels of more than 100 mg/dL included a greater frequency of drug therapy (65% versus 38%), more rigorous dietary compliance, longer follow-up (586 +/- 317 days versus 493 +/- 264 days), more favorable weight change (-0.3 +/- 4.9 kg versus +1.7 +/- 5.0 kg), and more extensive weekly exercise (183 +/- 118 minutes versus 127 +/- 107 minutes). CONCLUSION: The registered nurses managed the lipids of these patients as effectively as did the preventive cardiologists. Appropriate drug therapy was the most important factor in achieving an LDL cholesterol level of 100 mg/dL or less, but 35% of patients attaining this NCEP goal were not receiving drug therapy. Exercise, dietary compliance, and weight loss were also important factors.     

Basal and post-methionine serum homocysteine and lipoprotein abnormalities in patients with chronic liver disease.

BACKGROUND: Lipoprotein abnormalities are commonly found in chronic liver diseases (CLDs), particularly hypercholesterolemia in primary biliary cirrhosis (PBC). However, affected patients may not be at increased risk of coronary heart disease. Cirrhotic patients display impaired methionine clearance, and an increased level of homocysteine, a methionine metabolite, is an independent risk factor for coronary heart disease. Thus, we hypothesized that the low risk of coronary heart disease in patients with CLD may be related to low serum levels of homocysteine. The aim of this study was to test this hypothesis after methionine load and to describe the serum lipoprotein profile in patients with PBC and in patients with hepatocellular liver disease. METHODS: Fifteen female patients (mean age, 58.2 +/- 11.7 years) with PBC, 15 female patients (mean age, 54.5 +/- 9.6 years) with other causes of CLD, and 15 healthy sex- and age-matched controls were given L-methionine (50 mg/kg of ideal body weight). Basal fasting serum homocysteine level and 2, 4, and 6 hours of post-methionine load were determined using high-performance liquid chromatography with a fluorometric detector. Levels of fasting serum cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), lipoprotein (a) (Lp(a)), and apoprotein B were also determined. RESULTS: Results showed that mean basal and post-methionine load (6 hours) serum homocysteine levels were statistically significantly higher in the patients with PBC and with CLD than in the control group (P=0.04) and that levels of serum cholesterol, LDL, HDL, and apoprotein B were significantly higher in the PBC patients than in the other two groups (P < or = 0.05). There was no correlation between any of these parameters and the severity of liver disease. Serum HDL was significantly lower in the CLD group (P < or = 0.05) and correlated with severity of liver disease. There was no significant difference in serum cholesterol, LDL, or apoprotein B between the CLD group and the controls. Serum triglyceride and Lp(a) levels were similar for all three groups. CONCLUSIONS: In contrast to previous reports, the site of the methionine metabolic impairment was found to be below the homocysteine synthesis level. For most patients with CLD, factors other than serum homocysteine or Lp(a) are responsible for the reduction in the risk of coronary heart disease. Further studies with larger samples are needed.     

Differential influence of LDL cholesterol and triglycerides on lipoprotein(a) concentrations in diabetic patients

OBJECTIVE: To evaluate the relationship between plasma lipid profiles and lipoprotein(a) [Lp(a)] concentrations in diabetic patients, taking into account the Lp(a) phenotype. RESEARCH DESIGN AND METHODS: We included 191 consecutive diabetic outpatients (69 type 1 and 122 type 2 diabetic patients) in a cross-sectional study Serum Lp(a) was determined by enzyme-linked immunosorbent assay, and Lp(a) phenotypes were assessed by SDS-PAGE followed by immunoblotting. The statistical methods included a stepwise multiple regression analysis using the Lp(a) serum concentration as the dependent variable. The lipid profile consisted of total cholesterol, HDL cholesterol, LDL cholesterol, corrected LDL cholesterol, triglycerides, and apolipoproteins AI and B. RESULTS: In the multiple regression analysis, LDL cholesterol (positively) and triglycerides (negatively) were independently related to the Lp(a) concentration, and they explained the 6.6 and 7.8% of the Lp(a) variation, respectively. After correcting LDL cholesterol, the two variables explained 3.8 and 6.4% of the Lp(a) variation, respectively. In addition, we observed that serum Lp(a) concentrations were significantly lower in patients with type IV hyperlipidemia (mean 1.0 mg/dl [range 0.5-17], n = 16) than in normolipidemic patients (6.5 mg/dl [0.5-33.5], n = 117) and in type II hyperlipidemic patients (IIa 15.5 mg/dl [3.5-75], n = 13; IIb 9 mg/dl [1-80], n = 45); P < 0.001 by analysis of variance. CONCLUSIONS: Lp(a) concentrations were directly correlated with LDL cholesterol and negatively correlated with triglyceride levels in diabetic patients. Therefore, our results suggest that the treatment of diabetic dyslipemia may indirectly affect Lp(a) concentrations.     

First steps toward the establishment of a German low-density lipoprotein-apheresis registry: recommendations for the indication and for quality management.

New recommendations for the indication of treatment with selective extracorporeal plasma therapy low-density lipoprotein apheresis (LDL-apheresis) in the prevention of coronary heart disease are urgently needed. The following points are the first results of the ongoing discussion process for indications for LDL-apheresis in Germany: all patients with homozygous familial hypercholesterolemia with functional or genetically determined lack or dysfunction of LDL receptors and plasma LDL cholesterol levels >13.0 mmol/L (>500 mg/dL); patients with coronary heart disease (CHD) documented by clinical symptoms and imaging procedures in which over a period of at least 3 months the plasma LDL cholesterol levels cannot be lowered below 3.3 mmol/L (130 mg/dL) by a generally accepted, maximal drug-induced and documented therapy in combination with a cholesterol-lowering diet; and patients with progression of their CHD documented by clinical symptoms and imaging procedures and repeated plasma Lp(a) levels >60 mg/dL, even if the plasma LDL cholesterol levels are lower than 3.3 mmol/L (130 mg/dL). Respective goals for LDL cholesterol concentrations for high-risk patients have been recently defined by various international societies. To safely put into practice the recommendations for LDL-apheresis previously mentioned, standardized treatment guidelines for LDL-apheresis need to be established in Germany that should be supervised by an appropriate registry.     

Short-term and long-term effects of low-density lipoprotein (LDL) apheresis on restenosis after percutaneous transluminal coronary angioplasty (PTCA): is lowering Lp(a) by LDL apheresis effective on restenosis after PTCA?

It has been reported that serum lipoprotein(a) (Lp[a]) levels in patients with restenosis after percutaneous transluminal coronary angioplasty (PTCA) were significantly higher than in patients without restenosis. In this study, we evaluated the preventive effect of LDL apheresis on restenosis after PTCA in patients with hypercholesterolemia. For 10 patients who had shown a serum cholesterol level of more than 220 mg/dl despite treatment with antihypercholesterolemic drugs, LDL apheresis was conducted every 2 weeks after a successful PTCA until restenosis could be checked. In 4 patients, LDL apheresis was conducted for 2 years. LDL apheresis significantly reduced serum cholesterol from 248 +/- 22 mg/dl to 135 +/- 26 mg/dl and Lp(a) from 42 +/- 34 mg/dl to 21 +/- 16 mg/dl. The average degree of stenosis in the 11 lesions undergoing PTCA was 92 +/- 6% before PTCA, 35 +/- 10% immediately after PTCA, and 38 +/- 19% at 3 to 4 months after PTCA. Restenosis was observed in only 1 lesion. In 4 patients who received LDL apheresis for 2 years, restenosis did not occur in any of the 4 lesions treated. We concluded that LDL apheresis was an efficacious therapy to prevent restenosis after PTCA in patients with hypercholesterolemia.     

The association between fibrate use, change in high-density lipoprotein cholesterol, and the risk of cardiovascular disease: a retrospective chart review involving up to 8 years of follow-up

BACKGROUND: Clinical trials have indicated that the use of fibric acid derivatives confers a benefit against cardiovascular disease (CVD) in selected populations. However, whether fibrates provide a CVD risk reduction independent of changes in the traditional lipoprotein fractions and other known CVD risk factors is not clear. OBJECTIVE: This study examined whether the use of fibrate therapy in a general clinical setting provided cardiovascular benefits independent of changes in the traditional lipoprotein fractions. METHODS: This was a matched, retrospective cohort study. From the electronic records of a large health maintenance organization in the northwestern United States, we identified a population that had newly initiated fibrate pharmacotherapy between January 1, 1996, and December 31, 2000. We then identified a comparator group of patients not using fibrates, matching them to fibrate users based on high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) levels, age, sex, and year of HDL-C and TG measurement. Subjects were followed until a CVD hospitalization, termination from the health plan, or December 31, 2003, whichever came first. We then used multivariate analysis accounting for differences in followup to identify predictors of CVD incidence. RESULTS: The study population included 1722 matched pairs (56.6% male; mean [SD] age, 57.3 [11.1] years). The patients who had newly initiated fibrate pharmacotherapy had low baseline HDL-C levels (mean, 37.4 mg/dL) and very high TG levels (617 mg/dL). The 2 groups were similar overall, with the only significant differences between fibrate users and nonfibrate controls being a greater prevalence of diabetes (37.7% vs 34.3%, respectively; P=0.040) and greater use of angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers (56.6% vs 51.6%, respectively; P=0.003), beta-blockers (53.7% vs 49.0%; P=0.006), calcium channel blockers (25.1% vs 20.9%; P=0.004), and niacin (11.7% vs 7.4%; P<0.001). Overall, CVD risk was 26% lower for every 5-mg/dL increment in HDL-C. After adjustment for age, sex, smoking history, diabetes, existing diagnosis of CVD, weight, systolic blood pressure, baseline HDL-C, change in HDL-C, total cholesterol, TG, and use of statins, niacin, and other CVD drugs, fibrate use did not confer an additional CVD risk reduction. CONCLUSIONS: In this cohort with low baseline HDL-C levels and very high TG levels, fibrate use did not confer an independent CVD risk reduction after adjustment for CVD risk factors. Given the current obesity epidemic in the United States and the corresponding rise in the number of patients with the metabolic syndrome, the apparent risk reduction observed in association with higher HDL-C levels should not be ignored.     

Oxidized low-density lipoprotein and atherosclerosis

Atherosclerosis is the leading cause of morbidity and mortality in western society. The most important risk factors for atherosclerosis include smoking, hypertension, dyslipidemia, diabetes and a family history of premature atherosclerosis. Several studies indicate that an increased plasma low density lipoprotein (LDL) cholesterol constitutes a major risk factor for atherosclerosis. Many data support a proatherogenic role for oxidized LDL and its in vivo existence. The oxidative susceptibility of LDL is increased with established cardiovascular risk factors, such as diabetes, smoking and dyslipidemia. Supplementation with antioxidants such as ascorbate and alpha-tocopherol can decrease LDL oxidation as well as cardiovascular mortality and thus shows promise in the prevention of atherosclerosis.     

The familial hypercholesterolemia regression study: a randomized comparison of therapeutic reduction of both low-density lipoprotein and lipoprotein(a) versus low-density lipoprotein alone.

Lipoprotein (a) [Lp (a)] is a risk factor for coronary heart disease (CHD), especially in the presence of a raised low-density lipoprotein (LDL)-cholesterol (LDL-C). To ascertain whether reduction of both LDL and Lp(a) is more advantageous than reduction of LDL alone, patients with heterozygous FH and CHD were selected randomly to receive either LDL apheresis fortnightly plus simvastatin 40 mg/day or colestipol 20 g plus simvastatin 40 mg/day. Quantitative coronary angiography was undertaken before and after 2.1 years. Changes in serum lipids were similar in both groups except for the greater reduction of LDL-C and Lp(a) by apheresis. There were no significant differences in primary angiographic endpoints, and none of the angiographic changes correlated with Lp(a). Although LDL apheresis plus simvastatin was more effective than colestipol plus simvastatin in reducing LDL-C and Lp(a), it was not more beneficial in influencing coronary atherosclerosis. Decreasing Lp(a) seems unnecessary if LDL-C is reduced below 130 mg/dl.     

Detection of electronegative low density lipoprotein (LDL-) in plasma and atherosclerotic lesions by monoclonal antibody-based immunoassays

OBJECTIVES: To produce a monoclonal antibody (MAb) against electronegative LDL (LDL-) for detecting this modified lipoprotein in blood plasma and tissues. DESIGN AND METHODS: LDL- was isolated from human blood plasma and used as an antigen for immunization of Balb/c mice. Lymphocytes of immunized mice were fused with myeloma cells (SP2/0) to obtain the hybridomas. LDL- was detected in blood plasma and atherosclerotic lesions of humans and rabbits by MAb-based ELISA and immunohistochemistry, respectively. RESULTS: LDL- concentrations were higher (P < 0.05) in the blood plasma of hypercholesterolemic subjects (HC, 248 +/- 77 mg/dL of total cholesterol) than in normolipidemic subjects (NL, 173 +/- 82 mg/dL of total cholesterol) and rabbits (HC, 250 +/- 15 mg/dL of cholesterol versus NL, 81 +/- 12 mg/dL of cholesterol). Moreover, LDL- was detected in the atherosclerotic lesions of humans and rabbits. CONCLUSION: These MAb-based immunoassays are adequate to detect LDL- in biological samples and represent an important tool for investigating the role of LDL- in atherosclerosis.     

Apolipoprotein(a) phenotypes, Lp(a) concentration and plasma lipid levels in relation to coronary heart disease in a Chinese population: evidence for the role of the apo(a) gene in coronary heart disease.

Elevated lipoprotein(a) (Lp[a]) concentrations are associated with premature coronary heart disease (CHD). In the general population, Lp(a) levels are largely determined by alleles at the hypervariable apolipoprotein(a) (apo[a]) gene locus, but other genetic and environmental factors also affect plasma Lp(a) levels. In addition, Lp(a) has been hypothesized to be an acute phase protein. It is therefore unclear whether the association of Lp(a) concentrations with CHD is primary in nature. We have analyzed apo(a) phenotypes, Lp(a) levels, total cholesterol, and HDL-cholesterol in patients with CHD, and in controls from the general population. Both samples were Chinese individuals residing in Singapore. Lp(a) concentrations were significantly higher in the patients than in the population (mean 20.7 +/- 23.9 mg/dl vs 8.9 +/- 12.9 mg/dl). Apo(a) isoforms associated with high Lp(a) levels (B, S1, S2) were significantly more frequent in the CHD patients than in the population sample (15.9% vs 8.5%, P less than 0.01). Higher Lp(a) concentrations in the patients were in part explained by this difference in apo(a) allele frequencies. Results from stepwise logistic regression analysis indicate that apo(a) type was a significant predictor of CHD, independent of total cholesterol and HDL cholesterol, but not independent of Lp(a) levels. The data demonstrate that alleles at the apo(a) locus determine the risk for CHD through their effects on Lp(a) levels, and firmly establish the role of Lp(a) as a primary genetic risk factor for CHD.     

Low-density lipoprotein apheresis for the treatment of refractory hyperlipidemia

The advent of treatment with 3-hydroxy-3-methylglutaryl coenzyme A inhibitors has meant that, with a combination of diet and drug therapy, adequate control of serum cholesterol concentrations can be achieved in most patients with hypercholesterolemia. However, some patients, primarily those with familial hypercholesterolemia (FH), may require additional therapy to lower their cholesterol levels. In recent years, low-density lipoprotein (LDL) apheresis has emerged as an effective method of treatment in these patients. The criteria for commencement of LDL apheresis are LDL cholesterol levels of 500 mg/dL or higher for homozygous FH patients, 300 mg/dL or higher for heterozygous FH patients in whom medical therapy has failed, and 200 mg/dL or higher for heterozygous FH patients with documented coronary disease and in whom medical therapy has failed. In addition to cholesterol lowering in patients with FH, other indications for LDL apheresis are emerging. These include its use in the treatment of graft vascular disease in patients receiving cardiac transplants as well as in the treatment of certain glomerulonephritides. This review examines the role of LDL apheresis in the management of lipid disorders and the evidence available to support its use in clinical practice.     

Prognostic evaluation of primary non-small cell lung carcinoma patients using biological fluid variables. A systematic review

There is growing experimental evidence to suggest the role of oxidatively modified low‐density lipoprotein (LDL) in the initiation and progression of atherosclerosis. The oxidation of lipoprotein moiety causes modification of positively charged lysine residues and results in negative net charge of lipoprotein particles. Objective: To measure the amount of circulating electronegatively charged LDL particles (LDL–) in plasma of patients with angiographically documented coronary artery disease (CAD). Methods: Thirty patients were assigned to the study group (CAD+) and 10 patients to the control group (Ctrl). LDL– was quantitated in homogeneous LDL fractions obtained by ultracentrifugation, using ion exchange high performance liquid chromatography. Plasma lipids were measured using enzymatic kits. Results: The CAD+ group had significantly higher levels of LDL– in the whole LDL fraction (7.66±1.92 vs. 5.14±0.84%, p=0.0003). Moreover the CAD+ group had significantly higher levels of total cholesterol (255.4±35.1 vs. 210.4±22.4?mg/dL), LDL cholesterol (154.5±26.9 vs. 122.4±21.1?mg/dL) and significantly lower levels of high‐density lipoprotein (HDL) cholesterol (40.4±9.4 vs. 51.0±11.5?mg/dL). LDL– remained significantly higher in the CAD+ group after adjustment for total cholesterol, LDL cholesterol and HDL cholesterol (6.3 vs. 5.14% at p=0.0095). There is a trend towards a positive correlation between LDL– levels and LDL cholesterol in the control group (Spearman R=0.55 at p=0.098). Conclusions: Electronegatively charged LDL appears to be an additional hallmark of coronary artery disease, independently of established lipid risk factors. The trend towards a positive correlation between LDL cholesterol concentration and the level of LDL– in the control group may reflect the susceptibility of LDL cholesterol to autoxidation, Moreover, this may indicate other oxidative mechanisms in coronary artery disease. Nonetheless, further studies assessing the prognostic value of electronegatively charged LDLs are necessary.     

Lipoprotein apheresis affects lipoprotein particle subclasses more efficiently compared to the PCSK9 inhibitor evolocumab,a pilot study

Lipoprotein apheresis and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are last therapeutic resorts in patients with familial hypercholesterolemia (FH). We explored changes in lipoprotein subclasses and high-density lipoprotein (HDL) function when changing treatment from lipoprotein apheresis to PCSK9 inhibition.We measured the levels of low-density lipoprotein (LDL) and HDL particle subclasses, serum amyloid A1 (SAA1), paraoxonase-1 (PON1) activity and cholesterol efflux capacity (CEC) in three heterozygous FH patients. Concentrations of all LDL particle subclasses were reduced during apheresis (large 68.0?±?17.5 to 16.3?±?2.1?mg/dL, (p?=?0.03), intermediate 38.3?±?0.6 to 5.0?±?3.5?mg/dL (p?=?0.004) and small 5.0?±?2.6 to 0.2?±?0.1?mg/dL (p?=?0.08)). There were non-significant reductions in the LDL subclasses during evolocumab treatment. There were non-significant reductions in subclasses of HDL particles during apheresis, and no changes during evolocumab treatment. CEC was unchanged throughout the study, while the SAA1/PON1 ratio was unchanged during apheresis but decreased during evolocumab treatment.In conclusion, there were significant reductions in large and intermediate size LDL particles during apheresis, and a non-significant reduction in small LDL particles. There were only non-significant reductions in the LDL subclasses during evolocumab treatment.