Cholesterol efflux from macrophages mediated by high-density lipoprotein subfractions, which differ principally in apolipoprotein A-I and apolipoprotein A-II ratios.

High-density lipoprotein (HDL) was fractionated by preparative isoelectric focussing into six distinct subpopulations. The major difference between the subfractions was in the molar ratio of apolipoprotein A-I to apolipoprotein A-II, ranging from 2.1 to 0.5. The least acidic particles had little apolipoprotein A-II, were larger and contained the most lipid. The efflux capacity of the HDL subfractions was tested with mouse peritoneal macrophages and a mouse macrophage cell line (P388D1), either fed with acetylated low-density lipoprotein or free cholesterol. All the HDL subfractions were equally able to efflux cholesterol. The efflux was concentration dependant and linear for the first 6 h. The HDL subfractions bound with high affinity (Kd = 6.7-7.9 micrograms/ml) at 4 degrees C to the cell surface of P388D1 cells (211,000-359,000 sites/cell). Ligand blotting showed that all the HDL subfractions bound to membrane polypeptides at 60, 100, and 210 kDa. These HDL binding proteins may represent HDL receptors. In summary HDL particles, which differed principally in ratio of apolipoprotein A-I to apolipoprotein A-II behaved in a similar manner for both cholesterol efflux and cell surface binding.

Fibrinogen promotes monocyte adhesion via a protein kinase C dependent mechanism.

The accumulation of blood monocytes at sites of predilection of the vessel wall is an early cellular event of atherogenesis. Proteins of the vessel wall may facilitate monocyte adhesion and thus promote their recruitment. It has been shown that the relative content of extracellular fibrinogen increases during lesion development, and this study investigated the contribution of immobilized fibrinogen to monocyte adhesion and the underlying mechanism. Freshly isolated human blood monocytes were cultivated in serum-free RPMI 1640 in tissue culture wells precoated with albumin, fibrinogen, or fibrin. After 16 h the plates were washed and adherent cells enumerated. Immobilized fibrinogen enhanced monocyte adhesion more than 1.9-fold compared to immobilized albumin or fibrin (P < 0.05). Concomitant addition of the protein kinase C (PKC) inhibitors staurosporine or H7 suppressed monocyte adherence to immobilized fibrinogen but exerted no significant effect upon adhesion to any other surface tested. Stimulation of monocytes using phorbol myristate acetate resulted in increased binding of monocytes on fibrinogen but not on bovine serum albumin. When PKC activity was reduced through prolonged incubation with PMA for 16 h, a significant reduction of monocyte adhesion on fibrinogen was observed. Peptides containing RGD sequences, which have been demonstrated to be ligands for certain integrins, did not inhibit monocyte adhesion. The data suggest that fibrinogen promotes monocyte adhesion in vitro by a PKC-dependent mechanism. PKC appears to be important not only for the initial cell adhesion but also for sustained binding of monocytes to fibrinogen.

Endovenous laser ablation of varicose veins with the 1470 nm diode laser using a radial fiber - 1-year follow-up.

BACKGROUND: Endovenous laser ablation is one of the most accepted treatment options for insufficient great and small saphenous veins. The aim of this study was to investigate the long-term efficacy and safety of the radial fiber (ELVeS-radial kit™) for the 1470 nm diode laser in a 1-year follow-up. METHODS: A total of 308 lower limbs with primary insufficiency of great and small saphenous veins or insufficient tributaries were included in the prospective observational cohort study. The primary efficacy endpoint of the study was ultrasonographic proven elimination of venous reflux after at least 1 year. Secondary efficacy and further safety end points after 1 year were as follows: (1) sonographic exclusion of recanalization of the treated vein segments, (2) deep vein thrombosis, clinical pulmonary embolism or superficial vein thrombosis as defined by objective testing, (3) death from any cause, (4) persistent clinical complaints such as pain and paresthesia, (5) recurrent varicose veins. Patient satisfaction was assessed using a CIVIQ-2 questionnaire after 1 year. RESULTS: Follow-up could be completed in 91.2% of the patients. Excellent efficacy numbers with 99.6% occlusion of the treated varicose veins as elimination of reflux could be demonstrated. After 1 year, 96% of the treated veins disappeared completely sonographically; one recanalization was observed. No deep vein thrombosis or pulmonary embolism occurred, three superficial vein thrombosis were diagnosed in follow-up examinations. Four patients died, not related to pulmonary embolism. No persistent pain or paresthesia occurred in the follow-up. Recurrent varicose veins were diagnosed in 10 patients (2.81%). CONCLUSION: One-year follow-up showed that endovenous laser treatment of varicose veins with 1470 nm diode laser using the radial fiber is highly effective, also regarding in a 1-year follow-up.

Lipid levels in monocytes of patients with moderate hyperlipoproteinemia.

Recent studies suggest that circulating blood monocytes may serve as a lipid clearance system in early atherosclerotic lesions. To evaluate the influence of moderate hyperlipoproteinemia on monocyte lipid concentrations, we measured fasting serum and monocyte lipid levels in 7 healthy individuals, in 7 patients with primary hypercholesterolemia and in 17 patients with secondary dyslipidemia due to chronic renal failure; 10 of these patients were treated by hemodialysis (HD) and 7 patients by continuous ambulatory peritoneal dialysis (CAPD). The hypercholesterolemic patients had elevated serum levels of total cholesterol, LDL-cholesterol and apolipoprotein (apo) B, but normal plasma triglycerides. Patients on dialysis had elevated serum levels of triglycerides, serum cholesterol (CAPD only) and VLDL- and LDL-cholesterol (CAPD only) and apo B (CAPD only), whereas HDL-cholesterol and apo A-I levels (HD only) were decreased. In monocytes, we measured the content of free cholesterol (FC), cholesteryl esters (CE) and triglycerides (TG). The normal mean intracellular concentrations of FC, CE and TG were 48.3, 1.7 and 2.4 micrograms/mg cell protein, respectively. All monocyte lipid levels were similar in patients and controls, with the exception of a decreased content of FC (30.8 micrograms/mg) in monocytes of HD patients. We conclude that moderate increases in serum lipoprotein lipid levels are not associated with lipid accumulation in monocytes.

Chemotaxis of the monocyte cell line U937: dependence on cholesterol and early mevalonate pathway products.

In the present study we investigated the influence of cholesterol depletion and hydroxymethylglutaryl-coenzyme A reductase (HMG-CoA reductase) inhibition on chemotaxis of the human monocytic cell line U937. Chemotaxis was nearly completely depressed after incubation for 24 h in the absence of lipoproteins. This was accompanied by a significant decrease in cellular cholesterol. Addition of 10 micrograms/ml low density lipoprotein (LDL) for 2 h to the cholesterol-depleted cells restored chemotaxis. Free cholesterol had no effect under these conditions. Inhibition of HMG-CoA reductase by pravastatin (0.01-1.0 mM) for 20 or 72 h also reduced chemotaxis. However, this effect was not accompanied by a decrease in cellular cholesterol when cells were grown in the presence of lipoproteins. The effect of pravastatin could be reversed by the addition of mevalonate. Addition of LDL did not change the response to pravastatin. We propose that the availability of cholesterol plays an important role in cellular chemotaxis. Furthermore, it can be suggested that other products of the mevalonate pathway apart from cholesterol may contribute to the regulation of chemotaxis.

Treatment of primary hypercholesterolemia: fluvastatin versus bezafibrate.

The effects of fluvastatin and bezafibrate on lipids, lipoproteins, and apoproteins (apo) were investigated in a multicenter randomized, double-blind, parallel-group study. After 8 weeks of strictly controlled (computer-based assessment) dietary stabilization, patients with primary hypercholesterolemia (low-density lipoprotein cholesterol [LDL-C] > or = 160 mg/dL; triglycerides < or = 300 mg/dL) were enrolled into a 6-week placebo phase. Altogether, 131 patients were randomized to receive either fluvastatin at 40 mg once daily (n = 64; mean age 53 years) or bezafibrate at 400 mg once daily (n = 67; mean age 52 years) for 12 weeks. Compliance with the diet was monitored (3-day food records) after 6 and 12 weeks. Fluvastatin led to significant reductions in LDL-C (-23%), total cholesterol (-17%), LDL-C/high-density lipoprotein cholesterol (HDL-C) (-24%) and apo B (-19%). Fluvastatin significantly increased LpA-I (+8%) and apo E (+20%). Bezafibrate produced significant reductions in LDL-C (-17%), total cholesterol (-13%), LDL-C/HDL-C (-24%), triglycerides (-28%), apo B (-15%), and LpA-I (-10%) and significantly increased HDL-C (+12%), apo A-I (+9%), apo A-II (+30%), apo E (+14%), and Lp(a) (+3%). No clinically notable increases in levels of liver enzymes or creatine phosphokinase were observed with either treatment. Both treatments were well tolerated. There was a low incidence of adverse events that tended to be mild and included headache, muscular pain, angina, and dyspepsia. The frequency of adverse events was similar in both treatment groups, and no significant differences in dietary behavior were observed. In conclusion, fluvastatin is a well tolerated 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor for the treatment of primary hypercholesterolemia. Effects of fluvastatin on LpA-I occur irrespective of changes in HDL-C.

Effects of lipoprotein (a) on success rate of thrombolytic therapy in acute myocardial infarction.

Lipoprotein (a) [Lp(a)] and plasminogen share a high degree of homology as recently evidenced by amino acid and deoxyribonucleic acid analysis. As Lp(a) is enzymatically inactive, it has been suggested that high levels of Lp(a) may suppress the profibrinolytic activity at the cell surface and increase the risk for arteriosclerosis and thrombosis by competitive inhibition of plasminogen. The present study evaluated whether high levels of Lp(a) influence thrombolytic therapy in patients with acute myocardial infarction. Forty-one patients with acute myocardial infarction received a combination low-dose thrombolytic therapy with recombinant tissue-type plasminogen activator (rt-PA) and human single-chain urokinase-type plasminogen activator (scu-PA). This regimen did not induce plasminemia or a lytic state as indicated by well-maintained levels of fibrinogen. Coronary patency was assessed angiographically 90 minutes after initiation of treatment. Thrombolysis was successful in 30 and unsuccessful in 11 patients. Patients with high Lp(a) levels (greater than or equal to 25 mg/dl) (n = 9) responded equally well to thrombolytic therapy (8 of 9, patency 89%) as did patients with normal or low levels of Lp(a) (22 of 32, patency 70%, difference greater than 0.1). Lp(a) levels did not differ significantly between patients with successful and unsuccessful thrombolysis. Our results demonstrate that high levels of Lp(a) do not affect thrombolysis in patients with acute myocardial infarction when low-dose pharmacologic concentrations of rt-PA and scu-PA are applied in combination.

Predictive value of lipid profile for salutary coronary angiographic changes in patients on a low-fat diet and physical exercise program.

In this study, 113 patients with modestly elevated levels of low-density lipoprotein cholesterol (<210 mg/dl) and coronary artery disease were randomized to an intervention group (n=56) or a control group (n=57). The intervention program consisted of daily exercise and a low-fat diet according to the American Heart Association's recommendation phase III; patients in the control group received "usual care" rendered by their private physician. After 1 year, complete data were available for all 92 patients (intervention: n=40; control: n=52) who underwent repeat coronary angiography. During the study course, patients in the intervention group showed an increase in apolipoprotein A-I(123 +/- 18 vs 129 +/- 20 mg/dl; p < 0.02) and apolipoprotein A-I/B (1.3 +/- 0.4 vs 1.5 +/- 0.4; p <0.01) and a decrease in apolipoprotein B (99 +/- 20 vs 89 +/- 18 mg/dl; p < 0.01), while apolipoprotein A-II remained unchanged (38 +/- 6 vs 38 +/- 6 mg/dl; p=NS). In the control group, there were no significant changes (apolipoprotein A-I, 124 +/- 17 vs 128 +/- 13 mg/dl; apolipoprotein A-II, 38 +/- 6 vs 39 +/- 6 mg/dl; apolipoprotein B, 100 +/- 21 vs 99 +/- 16 mg/dl; apolipoprotein A-I/B, 1.3 +/- 0.3 vs 1.4 +/- 0.5; all p=NS). As previously reported, there was a significant retardation of progression in patients in the intervention group (progression 23%, no change 45%, regression 32%) compared with the control group (progression 48%, no change 35%, regression 17%) (p < 0.05). Although retardation of progression was significantly associated with an increase in apolipoprotein A-I/B and a decrease in apolipoprotein B (p < 0.05), these gave way in multivariate analysis to changes in total cholesterol/high-density lipoprotein cholesterol, absolute levels of low-density lipoprotein cholesterol, and, in a subgroup of patients, to leisure-time physical activity (all p < 0.05). These data demonstrate that an intervention based on a low-fat diet and intensive physical exercise is capable of improving apolipoprotein levels, associated with retardation of progression of coronary artery disease. However, total cholesterol/high-density lipoprotein cholesterol and low-density lipoprotein cholesterol appear superior to apolipoproteins as metabolic markers for effective treatment in patients with coronary artery disease.

Impact of intensive physical exercise and low-fat diet on collateral vessel formation in stable angina pectoris and angiographically confirmed coronary artery disease.

This randomized study was performed to assess the effects of > 3 hours of physical exercise per week and low-fat diet on collateral formation in nonselected patients with coronary artery disease (intervention group, n = 56). Results were compared with those of patients in a control group (n = 57), who received usual care by their private physicians. Coronary lesions were assessed by quantitative coronary angiography at the beginning and after 1 year of study (n = 92). As previously reported, after 1 year there was a significant retardation of progression of coronary artery disease in the intervention group as compared with the control group. In this study, evaluation of collateral formation revealed no significant difference between both groups, and changes in hemodynamic and metabolic variables or leisure time physical activity were not related to changes in collateral formation. Although progression of the disease was significantly related to an increase in collateral formation, regression was significantly related to a decrease in collateral formation (p < 0.00001). Because patients in the intervention group exercised for > 3 hours/week, and patients with regression of coronary artery disease even dedicated 5 to 6 hours to leisure time physical activity per week, these findings question whether an exercise program within the safety tolerance of patients will be able to induce coronary collateralization in the presence of regression of coronary artery disease.

Effects of lipoprotein(a) on thrombolysis.

Lipoprotein(a) (Lp(a)) and plasminogen share a high degree of structural homology. Therefore it has been suggested that elevated levels of Lp(a) may inhibit the profibrinolytic activity at the cell surface and increase the risk of thrombosis by competitive inhibition of plasminogen. In the present study we evaluated whether high levels of Lp(a) affect thrombolytic therapy in patients with acute myocardial infarction. Forty-one patients with acute myocardial infarction were treated with a combination of recombinant tissue-type plasminogen activator and human single-chain urokinase-type plasminogen activator. Coronary patency was assessed angiographically 90 min after initiation of treatment. Thrombolysis was successful in 30 and unsuccessful in 11 patients. Patients with high Lp(a) levels (> 25 mg/dl) (n = 9) responded equally well to thrombolytic therapy (8 of 9, patency 89%) as did patients with normal or low levels of Lp(a) (22 of 32, patency 70%, difference P > 0.1). The results demonstrate that high levels of Lp(a) do not influence thrombolysis in patients with acute myocardial infarction when low-dose pharmacologic concentrations of recombinant tissue-type plasminogen activator and human single chain urokinase-type plasminogen activator are applied in combination.

[Cardiology quality assessment in Germany--pro and contra]. / Kardiologie--Qualitätssicherung in Deutschland. Pro und Contra.

The German National Institute for Quality in Healthcare has also developed a program of external quality assessment in the field of cardiology. Hospitals are committed to collect certain data of diagnostic coronary angiography, percutaneous coronary interventions and pacemaker implantations. If statistical abnormalities are observed a so called structured dialogue is implemented. The responsible physicians of the hospitals are asked to comment possible quality deficits. Appointed members of quality commissions examine the answers and can invite the responsible physicians for interviews or also visit the hospital. However the validity of the quality data is problematic, because audits or check-ups of quality assessment in place are lacking. Therefore the results should not be misused for a comparison or ranking of hospitals with each other. As long as the validity of the quality assessment has not been improved, the results should also not be accessible for other parties, such as health insurances.

[The importance of cholesterol-lowering in patients after coronary artery bypass surgery]. / Die Bedeutung der Cholesterinsenkung bei Patienten nach aortokoronarer Bypassoperation.

Patients with aortocoronary bypass surgery generally have a severe, advanced coronary atherosclerosis. An intensive risk-factor management should be of special importance in these patients. However, cholesterol treatment goals are the same for operated or non-operated patients with coronary artery disease. Effective cholesterol lowering does not only decrease the progression of atherosclerosis in native coronary vessels but also helps to prevent the development of atherosclerosis in venous bypass grafts. Clinical studies demonstrated that this leads to an improvement of clinical endpoints. Unfortunately we know from registries, that even in bypass patients recommended guidelines for cholesterol lowering are often not followed.

[Optimization of cholesterol reduction principles and clinical results of dual inhibition]. / Optimierte Cholesterinsenkung. Prinzip und klinische Resultate der dualen Hemmung.

Ezetimibe is a recently developed compound, which inhibits intestinal cholesterol absorption. Because there are hints for an increase of cholesterol absorption during statin therapy, the combination of Ezetimibe with a statin seems to be appropriate. This dual approach -- inhibition of intestinal cholesterol absorption and hepatic cholesterol synthesis -- offers a very potent reduction of cholesterol. The combination of statins with Ezetimibe leads to a further reduction of LDL-cholesterol up to 12-21%. The dual inhibition causes a more effective reduction of LDL-cholesterol than a statin monotherapy. LDL treatment goals can be reached more easily, and possible side effects of otherwise necessary high doses of statins can be avoided. Clinical endpoint studies with Ezetimibe are underway.

[Recurrent ventricular fibrillation in a patient with angiographically normal coronary arteries and intermittent ST segment elevation]. / Rezidivierendes Kammerflimmern bei einem Patienten mit angiographisch unauffälligen Koronararterien und intermittierenden ST-Segment-Elevationen.

We report on a patient who was admitted to the hospital because of severe angina pectoris. During hospitalization extensive ECG alterations and intermittent ventricular fibrillation were observed. However, coronary angiography showed normal coronary arteries and left ventricular function. Treatment with high-dose nitrates and Ca-antagonists gradually improved the patient's clinical situation. Although a Prinzmetal angina seemed likely, a vasculitis of the coronary arteries could not be excluded with certainty. Therefore, additional corticoid therapy was administered to the patient. After 5 weeks the patient was discharged from the hospital without any pathological clinical symptoms.

Atypical type III hyperlipoproteinemia in a patient with Ig A myelomatosis.

We studied a 58-year-old woman with severe therapy-refractory hyperlipidemia, xanthomatosis, and multiple myeloma (immunoglobulin A, lambda light chain). The lipid disorder became evident about half a year prior to the expression of myelomatosis. Clinical symptoms were similar to those found in classical type III hyperlipoproteinemia but the underlying metabolic defect was different from the one described in this primary dyslipoproteinemia. The patient has the heterozygous apolipoprotein E3/2 phenotype and her VLDL-cholesterol/serum-triglyceride ratio is unusually low at 0.05. Evidence is given that the hyperlipoproteinemia is due to an impaired catabolism of intermediate density lipoproteins probably because of a reduced hepatic triglyceride lipase activity.

[Increase in triglycerides after fat load in healthy probands]. / Untersuchungen zum Triglyceridanstieg nach Fettbelastung bei gesunden Probanden.

Aim of the study was to analyze postprandial lipid changes after an oral fat load (400 g cream) in normal probands (n = 15). In addition we studied the uptake of postprandial VLDL by macrophages. Whereas total cholesterol (Chol), and HDL-chol did not change, plasma triglycerides (TG) (from 91 +/- 37 to 181 +/- 80 mg/dl) and VLDL-TG (from 27 +/- 18 to 41 +/- 26 mg/dl) increased significantly, with a maximum at 3 h after the oral fat load. These changes were interindividually very different and depended neither on lipoprotein or hepatic lipase levels, nor on basic lipid levels. Different post-prandial VLDL-fractions, isolated before or 3 and 6 h after the fat load caused a comparable lipid accumulation in macrophages. It seems very likely that also postprandial lipid elevations may play a role in foam cell generation.

[New strategies in the treatment of restenosis]. / Neue Strategien zur Behandlung der Restenose.

Twenty-three years after introduction of coronary angioplasty (PTCA), the inhibition of restenosis formation continues to be the major challenge for the interventional cardiologist. About 35-50% of all patients undergoing PTCA develop a renarrowing of the intravascular lumen within the following six months. The use of specific systemic drug therapy as well as different angioplastic methods (rotablation, atherectomy, laser angioplasty) all failed to significantly reduce restenosis. Local drug delivery and local gene therapy have only shown to be effective in animal experiments. Restenosis can be reduced by the use of stents; however restenosis can also develop within the stents. The treatment of choice for severe in-stent restenosis may become radiotherapy, which seems to be a promising tool also for other forms of restenosis.

[New strategies to treat restenosis]. / Neue Strategien zur Behandlung der Restenose.

Twenty-three years after introduction of coronary angioplasty (PTCA), the inhibition of restenosis formation continues to be the major challenge for the interventional cardiologist. About 35-50% of all patients undergoing PTCA develop a renarrowing of the intravascular lumen within the following six months. The use of specific systemic drug therapy as well as different angioplastic methods (rotablation, atherectomy, laser angioplasty) all failed to significantly reduce restenosis. Local drug delivery and local gene therapy have only shown to be effective in animal experiments. Restenosis can be reduced by the use of stents; however restenosis can also develop within the stents. The treatment of choice for severe in-stent restenosis may become radiotherapy, which seems to be a promising tool also for other forms of restenosis.