The first results demonstrating efficiency and safety of a double-column whole blood method of LDL-apheresis.

LDL-apheresis is a treatment for familial hypercholesterolemia in addition to diet and drug therapy. In the past, LDL-apheresis techniques consisted in separating plasma from blood and adsorbing plasma LDL-C whereas recent methods remove LDL-C directly from whole blood. The whole blood system developed by Kaneka consists of a single-column (Liposorber DL-75) treatment (SCWB) but a double-column whole blood (DCWB) method has recently been developed (Liposorber DL-50 x 2). When 1.6 blood volumes (plus 1l) were processed, acute reductions of total cholesterol and LDL-C were 67.9+/-6% and 80.2+/-4.5%, respectively. The performances of the DCWB method were compared to other LDL-apheresis methods. Assessed in 10 patients, the DCWB method is more efficient than the SCWB method with higher reduction rates of LDL-C (79.7+/-4.9 vs. 68.2+/-5.0% p<0.0001) and apolipoprotein-B (79.5+/-5.4 vs. 67.4+/-5.4% p<0.0001). In a sub group of five patients having the highest LDL-C baseline levels, the LDL-C reduction rates obtained by the DCWB method are equivalent to those obtained by the conventional LDL-apheresis method consisting of preliminary plasma separation followed by plasma LDL-C adsorption and used as first line apheresis therapy (80.5+/-4.5 vs. 79.0+/-5.9%). The safety of DCWB was demonstrated in 12 patients with only a low frequency of mild and transient adverse effects (4%). In conclusion, the DCWB LDL-apheresis method provides efficient removal of LDL-C, a low level of adverse effects, and a shortened duration of the procedure.

Modulation of phenotypic expression of APOA5 Q97X and L242P mutations.

OBJECTIVE: To provide phenotypic and functional data in new patients with APOA5 mutations and to identify genetic and metabolic factors influencing their phenotypic expression. METHODS AND RESULTS: By sequencing APOA5 gene in a cohort of 286 hyperchylomicronemic subjects, free of LPL or APOC2 mutations, we identified 4 unrelated carriers of the Q97X mutation (3 heterozygotes and 1 homozygote) and one heterozygote with a new L242P mutation. Postheparin LPL activity level was reduced by about 50% in Q97X heterozygotes and more than 90% in the Q97X homozygote, but was normal in the L242P patient after resolution of hyperchylomicronemia. Plasma apoAV was undetectable in the Q97X homozygote and in the normal range in the L242P and Q97X heterozygous carriers. In Western blot studies, the association of apoAV with plasma lipoproteins was altered in Q97X heterozygous carriers but not in the L242P carrier. Hyperchylomicronemic heterozygotes for both mutations carried an additional APOA5 variant haplotype and/or APOE variant (E2 or E4). Type 2 diabetes or metabolic syndrome were not a major phenotypic determinant. CONCLUSIONS: The L242P mutation was present in a hyperchylomicronemic proband but its causal involvement remains to be established. The Q97X mutation was clearly involved in hyperchylomicronemia with evidence of concomitant altered intravascular lipolysis, and a complete apoAV deficiency in the homozygote. The phenotypic expression variability of APOA5 mutations was mostly influenced by compound heterozygosity with APOA5 variant haplotypes plus additional genetic factors, and in a lesser extent by the metabolic environment.