Influence Of Serum Lipids,Lipoprotein Cholesterol On HDL Subclasses Distribution

1. Alterations of HDL subclasses in endogenous hypertriglyceridemiaTo investigate the alterations of HDL subclasses in endogenous hypertriglyceridemic subjects. Apo-AI contents of serum HDL subclasses were quantitated by two-dimensional gel electrophoresis in 236 normolipidemic subjects (including 146 males and 90 females) and 176 endogenous hypertriglyceridemic subjects (including 103 males and 73 females). According to the Third Report of the National Cholesterol Education Program (ATP -III) guidelines, the subjects were divided into two groups: normolipidemic subjects group(TC< 6.21mmol/L and TG<2.26mmol/L) and hypertriglyceridemic subjects group(TC<6.21mmol/L and TG≥2.26mmol/L). Then the two groups were further classified by gender, respectively. The results showed that apo-AI contents of small-sized preβ₁ HDL, HDL_3a were significantly higher (p<0.01, p<0.01) ,but those of large-sized HDL_2a and HDL_2b were significantly lower (p < 0.01, p < 0.01) in hypertriglyceridemic subjects versus normolipidemic subjects. Moreover, with the elevation of TG levels, small-sized preβ₁-HDL and HDUa increased successively, however large-sized HDL_2a and HDL_2b decreased successively. Males had significantly higher apo-AIcontents of small-sized preBrHDL, HDI₃b(p<0.05, p<0.05), but lower those of large-sized HDL2b(p<0.01) than females in both normolipidemic and hypertriglyceridemic subjects. Conclusion: the particle size of HDL shifted towards smaller size in hypertriglyceridemic subjects, especially in male subjects. Of note, the shift was more obvious with the elevation of TG levels. The changes mentioned above indicate that HDL maturation might be abnormal, and reverse cholesterol transport might be weakened.2. Relationship between serum lipoprotein-cholesterol levels and HDL subclassesTo investigate the influence of serum HDL-C or LDL-C levels on the components of serum HDL subclasses. Apolipoprotein (apo)A-1 contents of serum HDL subclasses in 292 subjects were determined by two-dimensional gel electrophoresis associated with immunodection method. With the decrease of serum HDL-C levels, apoA-1 contents of pre P rHDL and HDUb increased . Compared with high HDL-C group, those of pre P rHDL(p<0.01) and HDUb(p<0.05 ) were significantly higher in low HDL-C group, while it was reversed for HDL2b and HDL2a.Compared with high HDL-C group, those of HDL2b and HDL2a were significantly lower (p<0.01) in middle and low HDL-C groups. With the increase of serum LDL-C levels, apoA-1 contents of preP rHDL.HDUc and HDUb increased. Compared with desirable LDL-C group, those of pre P rHDL and HDI₃b were significantly higher in high LDL-C group (p<0.05) and very high LDL-Cgroup (p<0.01) ,and those of HDUc were also significantly higher in very high LDL-C group (p<0.01 ) , while it was reversed for HDL2b.Compared with desirable LDL-C group, those of HDL2b were significantly lower in high LDL-C group (p<0.05) and very high LDL-C group(p<0.01). Conclusion: with the decrease- of serum HDL-C levels or increase of serum LDL-C levels, the' smaller sized HDL increased and the larger sized HDL decreased, furthermore HDL-C levels were more significant to influence the components of the larger sized HDL(HDL2a,HDL2b).3. Relationship between serum TC/HDL-C.TG/HDL-C ratio and HDL subclassesTo study the relationship between HDL subclasses and TC/HDL-C.TG/HDL-C ratio in serum. Apolipoprotein (apo)A- I contents of serum HDL subclasses in 292 subjects were determined by two-dimensional gel electrophoresis associated with immunodection method. Compared with low TC/HDL-C ratio subgroup, apoA-1 contents of pre P i-HDL (p<0.01, in middle or high subgroup) and HDL-3a (p<0.05, in high subgroup) were significantly higher, but those of HDL2b (p<0.01, in middle or high subgroup) and HDL2a (p <0.01, in high subgroup) were significantly lower. Compared with middle TC/HDL-C ratio subgroup, apoA-1 contents of prePrHDL , HDUa were significantly higher (p<0.01, p<0.05) ,but those of HDL2a and HDL2b were significantly lower (p<0.01, p<0.01 ) in high subgroup. Compared with low TG/HDL-C ratio subgroup, apoA- Icontents of pre P rHDL, HDUa were significantly higher (p<0.01, p< 0.05,in high subgroup) ,but those of HDL2a and HDL2b were significantly lower (p<0.01, p<0.01, in middle or high subgroup) . Compared with middle TG/HDL-C ratio subgroup, apoA-1 contents of preP 1-HDL , HDUa were significantly higher (p<0.01, p<0.05) ,but those of HDL2a and HDL2t> were significantly lower(p<0.01, p<0.01). In addition, TC,TG,TC/HDL-C ratio and TG/HDL-C ratio showed a positive correlation with apoA-1 contents of small-sized preP i-HDL and a negative correlation with those of large-sized HDL2b, but it was reversed for HDL-C. Conclusion: when TC/HDL-O5 or TG/HDL-O 2.2 in serum, the particle size of HDL shifted towards smaller sizes, which, in turn, indicates that reverse cholesterol transport might be weakened and HDL maturation might be abnormal.