Abstract
INTRODUCTION AND METHOD
Clinical significarices of plasma high density lipoprotein (HDL)-cholesterol (Ch) levels have been investigated extensively. However, following questions still remain to be answered:
1) Should all types of hypo-high density lipoproteinemia be treated?
2) Is hypo-high density lipoproteinemia a cuase or result of arteriosclerotic vascular diseases?
3) What kind of subfraction or component is responsible for antiatherogenecity of HDL?
4) Is it possible to prevent or regress atherosclerosis, when hypo-high density lipoproteinemia is recovered for a long time?
We have reported the heterogeneity of hypo-high density lipoproteinemia based on the characteristics of plasma lipoprotein compositions. We proposed to subdivide hypo-high density lipoproteinemia into two groups: Type I and Type II. In hypo-high density lipoproteinemia Type I, HDL-Ch/LDL-Ch ratio is low, and in Type II, it is normal or high. Furthermore, there may be two subtypes in Type I: Type Ia and Ib. In Type Ia, LDL-Ch level is not high, and in Type Ib, its level is high. The purpose of the present study was to investigate further the characteristics of plasma lipoprotein compositions of hypo-high density lipoproteinemia Type II. Our previous study indicated that Type II hypo-high density lipoproteinemia include dyslipoproteinemia observed in thyroid disease, especially hyperthyroidism and liver cirrhosis. Therefore, in the present study, we have investigated the plasma lipoprotein compositions of the patient with hyper- and hypothyroidism and liver cirrhosis. Lipoprotein fractions were isolated by sequential ultracentrifugation as previously reported.
RESULTS
(1) Plasma lipoprotein composition of the patients with hyperthyroidism
Plasma Ch (122±32mg/100ml) and LDL-Ch (68±23mg/100ml) of the patients with hyperthyroidism were significantly lower than plasma Ch (180±36mg/100ml) and LDL-Ch (110±29mg/100ml) in controls. HDL-Ch levels (46±11mg/100ml) was lower than that (54±10mg/100ml) in controls without statistical significance. HDL-Ch/LDL-Ch ratio of the patients was significantly higher than that in controls. Plasma triglyceride (TG) levels were significantly lower than that in controls. TG levels in VLDL, LDL and HDL were as high as those in controls. Plasma and LDL-phospholipid (PL) were significantly lower than those in controls. These alterations in lipoprotein composition were recovered to the values comparable to the values in controls by treatment of hyperthyroidism. Hypo-high density lipoproteinemia (HDL-Ch<40mg/100ml) was observed in 2 of 7 patients and types of hypo-high density lipoproteinemia of two patients were Type II.
(2) Plasma lipoprotein composition of the patients with hypothyroidism
Plasma Ch (264±64mg/100ml) and LDL-Ch (190±54mg/100ml) of the patients were significantly higher than plasma Ch (190±40mg/100ml) and LDL-Ch (119±31mg/100ml) in controls. HDL-Ch (49±15mg/100ml) of the patient was slightly lower than that (52±10mg/100ml) in controls without statistical significance. HDL-Ch/LDL-Ch ratio of the patients was significantly lower than that of controls. LDL-TG, LDL-PL of the patients were increased significantly. HDL-Ch level of one of 4 patients was 38mg/100ml and his type of hypo-high density lipoproteinemia was Type II.
(3) Correlation between plasma levels of T3, T4 and TSH and plasma lipoprotein concentrations
Plasma T3 and T4 levels showed negative correlations to lipids concentrations in LDL. Plasma TSH concentrations showed positive correlations to plasma, VLDL-and LDL-TG levels.
(4) Plasma lipoprotein composition of the patients with liver cirrhosis
Concentrations of plasma Ch, LDL-Ch, VLDL-TG, plasma PL and LDL-PL in the patients were significa
