ProAlgaZyme and its subfractions increase plasma HDL cholesterol via upregulation of ApoA1, ABCA1, and SRB1, and inhibition of CETP in hypercholesterolemic hamsters

摘要

Background: Plasma HDL cholesterol levels are inversely related to cardiovascular disease, which is the leading cause of death worldwide. This study investigated the effect of an algae infusion, ProAlgaZyme (PAZ), and its subfractions (P1, P2, P3, P4) on plasma HDL in a hamster model.Methods: Sixty male golden Syrian hamsters (8 weeks old) were randomized into controls (W) or PAZ (P), P1, P2, P3, and P4 (n = 10 per group). An infusion of either 5% (P1, P2, P3) or 20% (P, P4) concentration (v/v) was administered via the drinking water for 4 weeks, while the hamsters were being fed a high-fat diet (30% of calories from fat). Serum lipids were assayed and liver samples subjected to reverse transcription polymerase chain reaction to determine the relative transcription levels of genes involved in HDL/reverse cholesterol transport metabolism, ie, ApoA1, ABCA1, CETP, and SRB1.Results: Non-HDL cholesterol was significantly reduced in the P (P < 0.05), P3 and P4 (P < 0.001) groups as compared with the W group, while HDL cholesterol showed a significant increase in the P, P3, and P4 groups (P < 0.001). Moreover, the total cholesterol/HDL ratio was significantly improved in the P, P1, and P2 (P < 0.05), and P3 and P4 (P < 0.001) groups. The shift in cholesterol towards the higher density fractions was validated by density gradient ultracentrifugation. Real-time quantitative polymerase chain reaction showed a significant increase in hepatic ApoA1 (P, P4) and ABCA1 (P3, P4) expression, consistent with an increase in HDL production, biogenesis, and maturation. A two-fold increase in SRB1 expression indicates that P4 further augments the reverse cholesterol transport mechanism. Reduction of CETP expression (P4) is consistent with a decrease in the transfer of cholesteryl ester to LDL, further increasing the amount of cholesterol held as HDL particles.Conclusion: ProAlgaZyme and its subfractions significantly improved the plasma cholesterol profile by lowering non-HDL and increasing HDL, possibly via the reverse cholesterol transport mechanism.