Predictability of low-density lipoprotein levels during apheretic treatment of hypercholesterolaemia

Pregnancy in a patient with homozygous familial hypercholesterolemia treated with long-term low-density lipoprotein apheresis

The pregnancy and delivery of a subject with homozygous familial hypercholesterolemia (FH) and coronary artery disease (CAD) were monitored closely for signs of maternal and fetal distress. Biweekly treatment with low-density lipoprotein (LDL) apheresis using dextran-sulfate cellulose columns was continued throughout the pregnancy, and lipid and lipoprotein levels were evaluated. During the course of the pregnancy and delivery, no signs of maternal coronary insufficiency developed. Serial ultrasonographic measurements of fetal growth indices and the blood flow velocity waveforms (FVWs) of the uterine and umbilical artery did not reveal any sign of fetal growth retardation or insufficiency of the uteroplacental circulation, respectively. During pregnancy, time-averaged concentrations of serum total cholesterol (TC), LDL cholesterol (LDL-C), apolipoprotein (apo) B, and lipoprotein(a) [Lp(a)] showed a gradual decline. Notwithstanding LDL apheresis, a gradual twofold increase of serum triglyceride (TG) levels was found. In the second and third trimester, high-density lipoprotein cholesterol (HDL-C) levels showed a 55% increase that coincided with a 75% reduction in hepatic lipase activity in postheparin plasma, normalizing after parturition. After delivery, lp(a) levels showed an almost twofold increase, which could not be explained by the interruption of LDL apheresis alone, and may be caused by changes in gonadal steroids. Histologic examination of the placenta and the umbilical arteries revealed no atherosclerotic changes, infarctions, or lipid deposits. In general, long-term LDL apheresis in homozygous FH can delay the onset and complications of severe CAD. In case of a pregnancy, LDL apheresis seems feasible and should be continued during the pregnancy to prevent superimposed hyperlipidemia and placental insufficiency.

The mechanism of the production of superoxide by phagocytes

Superoxide is produced by phagocytic cells at rates sufficient to have cytocidal effects. A wide variety of receptor-dependent and -independent agonists triggers this respiratory burst, including immunoglobin aggregates, complement fragments, and leukotriene B4. Lower rates of O2-. production are triggered by addition of specific cytokines into B-lymphocytes, endothelial cells, fibroblasts, and kidney mesangial cells; low concentration of radicals may act as signals for proliferation or other changes. The NADPH oxidase of phagocytes, characterized by the presence of FAD and a low potential cytochrome b, is organized to transfer electrons electrogenically across the plasma membrane from NADPH to O2. A proton channel permits movement of compensating H+.

Reduction of lipoprotein(a) by LDL-apheresis using a dextran sulfate cellulose column in patients with familial hypercholesterolemia

Lipoprotein(a) (Lp(a)) was eliminated by LDL-apheresis using a dextran sulfate cellulose column in 3 homozygous and 10 heterozygous familial hypercholesterolemic patients. Immediately after LDL-apheresis by the LA-15 system (continuous LDL apheresis), there were significant reductions in Lp(a) concentrations (28.6 +/- 11.8 mg/dl (mean +/- S.E.) to 9.6 +/- 5.6 mg/dl (P < 0.01)), and in LDL-cholesterol concentrations (156 +/- 32 mg/dl to 48 +/- 18 mg/dl (P < 0.01)). Immediately following LDL-apheresis, Lp(a) and LDL-cholesterol were reduced by 67.4% +/- 11.6% and 68.3% +/- 11.8%, respectively. The removal of Lp(a) paralleled that of LDL-cholesterol. The reduced levels of Lp(a) nearly returned to baseline within 7 days. In 6 of the heterozygous FH patients the rates of recovery of LDL cholesterol and Lp(a) were calculated, according to Apstein's equation after discontinuing lipid altering drug treatment for 4 weeks. Mean constant k values of LDL cholesterol and Lp(a) were 0.354 (range: 0.136-0.752) and 0.427 (range 0.112-0.933), respectively. The average concentration during the 7 days following LDL-apheresis was calculated. Average reductions were 28% in LDL cholesterol and 18% in Lp(a). Pravastatin treatment, which continued for 4 weeks, significantly decreased LDL cholesterol (P < 0.01); however, before LDL-apheresis pravastatin treatment significantly increased Lp(a) levels (P < 0.05) in a small number (n = 6) of the FH patients, who had been regularly treated with LDL-apheresis. These results suggest that LDL-apheresis using the dextran sulfate cellulose column is an effective treatment to reduce levels of serum Lp(a) and LDL proportionally. This therapy may be of value in the prevention and regression of coronary artery disease in FH patients.