Small dense LDL concentration is closely associated with serum apolipoprotein B, comparisons of non-LDL cholesterol or LDL cholesterol

Small dense low-density lipoprotein (sd LDL) is more atherogenic than large buoyant (lb) LDL, which is relatively high in particle number (as estimated by apolipoprotein [apo] B) and poor in cholesterol (C) content. Because recent epidemiological studies have shown that serum apo B is a stronger predictor of the risk of coronary heart disease (CHD) than LDL-C, we assumed that this strong predictive power of apo B for CHD is attributable to a close association with sd LDL concentration. On the other hand, non-HDL-C has been proposed as an integrated CHD risk marker containing all atherogenic apo B-containing lipoproteins. We examined which apo B or non-HDL-C is superior marker in reflecting sd-LDL particles. Eighty-one subjects with dyslipidemia were studied. Sd LDL (density, 1.044 approximately .063g/ml) and large buoyant LDL (density, 1.019 approximately 1.044g/ml) were separated by the ultracentrifugation method and LDL size was measured by gradient gel electrophoresis. LDL-C, non-HDL-C, and apo B were highly associated with each other(r=0.78 approximately 0.87), and all were associated with C, apo B, and TG in sd-LDL. However, multivariate regression analysis revealed that only apo B was constantly and independently associated with sd-LDL concentrations. Mean LDL diameter was negatively associated with apo B but not with non-HDL-C. These results suggest that apo B is superior to non-HDL-C in reflecting a potent atherogenic lipoprotein, sd-LDL, which may explain a potent predictive power of apo B for CHD.     

Serum and liver cholesterol levels in experimental fever

A single intravenous injection of pyrogenal (10 g/kg) or a culture ofBacillus mesentericus (3·10⁹ bacterial cells/ml/kg body weight) lowered the total blood serum cholesterol concentration on account of its ester-bound fraction and increased both the ester-bound and the free cholesterol concentrations in the liver after 3 h. After 24 h, when the normal temperature was restored, the concentrations of cholesterol and its fractions in both the serum and liver were higher than initially.Department of Pathological Physiology, I. P. Pavlov First Leningrad Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR P. N. Veselkin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 4, pp. 46–47, April, 1975.     

LDL cholesterol in early pregnancy and offspring cardiovascular disease risk factors

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人胚肝低密度脂蛋白受体活性与血清胆固醇水平的关系

用卵磷脂/丙酮沉淀法测定经部分纯化的人胚肝LDL受体活性,结果发现,随着胎龄增加,肝脏LDL受体活性明显增高。与此同时,血清总胆固醇(TC)和LDL-胆固醇(LDL-C)水平进行性下降。胎龄与血清TC和LDL-C的相关系数分别为-0.80和-0.77,有显著意义(P<0.001)。进而发现,在胚肝LDL受体活性与血清TC和LDL-C之间也存在着明显的负相关,相关系数分别为-0.96和-0.95(P<0.001)。这一结果提示,在胎儿发育过程中,肝脏LDL受体对血胆固醇水平调节起着关键的作用。     

Effects of stress and ovariectomy on the plasma cholesterol, serum triglyceride, and aortic cholesterol levels of female rats

Female Sprague-Dawley rats were either ovariectomized or sham-operated prior to puberty. As adults, they were maintained on a cholesterol-supplemented diet and subjected to either predictable, controllable shock; unpredictable, uncontrollable shock; or no shock for 30 days (51-min daily sessions). Sham-operated rats had higher plasma cholesterol levels than ovariectomized rats, but neither group showed an effect of stress treatments. For both groups, serum triglyceride and aortic cholesterol levels were lower in stressed than nonstressed rats. Additionally, the ovariectomized rats had higher levels of serum triglycerides than sham-operated controls.     

Changes in serum cholesterol levels in Japan

Serum cholesterol levels in Japanese people have increased after World War II. The national surveys by Research Committee demonstrated an increase of approx. 10 mg/dl of serum cholesterol from 1960 to 1980 in every years of age. An increase of serum cholesterol is observed in Japanese, whereas a decrease in American during the 20 years. Although the Japanese cholesterol levels are much lower for the older people, those for younger group are higher than American levels. These results bring forward the problems in the incidence of ischemic heart diseases in young Japanese. It is considered that the changes in serum cholesterol levels are due to the changes in the proportion of the nutrients in the Japanese diets; energy from carbohydrates decreased, whereas ones from proteins and fats increased, with no significant changes in total calorie intake. In particular, the intakes of total and animal fats have increased more than 3.5 fold during the period. "Normal" values and ranges in laboratory medicine are generally derived as the mean +/- 2SD by the statistical method. Normal range, however, which are calculated from many laboratory data, have come into questions in case of serum cholesterol. The upper limits of the means +/- 2 SDs are often higher than the values obtained from the clinical and epidemiological findings. It has clarified that the medical cares are necessary even at lower cholesterol levels. Then, "normal" values and ranges must be decided not only by statistics, but by the clinical and epidemiological findings.     

Meta-analysis of the association between asthma and serum levels of high-density lipoprotein cholesterol and low-density lipoprotein cholesterol

Background

The reported associations of blood lipid profiles with asthma are ambiguous.

Low levels of serum vitronectin associated with clinical phases in patients with hemorrhagic fever with renal syndrome

β₃ integrin has been identified as a cellular receptor for Hantaan virus which causes hemorrhagic fever with renal syndrome (HFRS). As one of the ligands of β₃ integrin, vitronectin (VN) may be altered in HFRS. In this study, changes of serum VN levels were determined in 112 patients with HFRS and 30 age- and sex-matched healthy controls by quantitative sandwich enzyme immunoassay. The levels of serum VN were analyzed in patients at various phases of HFRS and with different severity of clinical types. Serum VN levels in patients with HFRS, at all clinical phases except the convalescent phase, were significantly decreased compared with those in the controls (P < 0.01). The serum levels of VN decreased at febrile phase, maintained at the lowest status during hypotensive and oliguric phases, started to increase from polyuric phase and reached almost normal condition till convalescent phase. The levels of serum VN between patients with milder and more severe clinical types showed no significant difference at each phase (P > 0.05). These results suggest that VN level was altered during the course of HFRS and chronological changes of serum levels of VN may correlate with the evolution of the disease.     

Evidence for a QTL on chromosome 19 influencing LDL cholesterol levels in the general population

The genetic basis of cardiovascular disease (CVD) with its complex etiology is still largely elusive. Plasma levels of lipids and apolipoproteins are among the major quantitative risk factors for CVD and are well-established intermediate traits that may be more accessible to genetic dissection than clinical CVD end points. Chromosome 19 harbors multiple genes that have been suggested to play a role in lipid metabolism and previous studies indicated the presence of a quantitative trait locus (QTL) for cholesterol levels in genetic isolates. To establish the relevance of genetic variation at chromosome 19 for plasma levels of lipids and apolipoproteins in the general, out-bred Caucasian population, we performed a linkage study in four independent samples, including adolescent Dutch twins and adult Dutch, Swedish and Australian twins totaling 493 dizygotic twin pairs. The average spacing of short-tandem-repeat markers was 6-8 cM. In the three adult twin samples, we found consistent evidence for linkage of chromosome 19 with LDL cholesterol levels (maximum LOD scores of 4.5, 1.7 and 2.1 in the Dutch, Swedish and Australian sample, respectively); no indication for linkage was observed in the adolescent Dutch twin sample. The QTL effects in the three adult samples were not significantly different and a simultaneous analysis of the samples increased the maximum LOD score to 5.7 at 60 cM pter. Bivariate analyses indicated that the putative LDL-C QTL also contributed to the variance in ApoB levels, consistent with the high genetic correlation between these phenotypes. Our study provides strong evidence for the presence of a QTL on chromosome 19 with a major effect on LDL-C plasma levels in outbred Caucasian populations.     

HDL-mediated cholesterol elimination from human arterial tissue. Influence of serum cholesterol levels

HDL-mediated cholesterol elimination was studied in mesenteric artery tissue obtained during jejuno-ileostomy in severely obese non-hypercholesterolemic patients. The cholesterol contents were determined in arterial specimens incubated with autologous HDL, in the incubation medium, and in non-incubated control specimens. In the patients with lower serum cholesterol levels (< ca. 6 mmol·1^?1) cholesterol was eliminated from the tissue during incubation. Elimination was stimulated by an increase in HDL in the incubate. In contrast, arterial tissue from patients with higher serum cholesterol levels (> ca. 6 mmol·1^?1) accumulated cholesterol during incubation. There was a statistically significant correlation between the change in arterial tissue cholesterol during incubation and serum cholesterol of the patients. These data suggest that elevated serum cholesterol levels may inhibit the capacity of HDL to cause a net transfer of cholesterol from arterial tissue. The mechanisms are not known but changes in the distribution of lipoprotein families within HDL may possibly be signficant.