Decreased serum cholesterol-binding reserve in premature myocardial infarction

Antiatherosclerotic potency of high density lipoprotein of different origins: a review and some new findings

The antiatherosclerotic potency of isolated high density lipoproteins (HDL) of different origins was investigated in three experimental models: (1) isolated HDL were injected into cholesterol-rich fed rabbits; (2) the effect of HDL on the intracellular level of free and esterified cholesterol as well as on proliferation of smooth muscle cells and fibroblasts was investigated in cell cultures; and (3) we studied the influence of isolated HDL fractions on thromboxane (TXB2) formation in clotting whole blood with different cholesterol content.

Lipid profiles in spinal cord injury

Measurement of blood levels of total cholesterol and lipoproteins (HDL and LDL) were conducted on 96 men with spinal cord injury, 46 paraplegics and 50 quadriplegics. All these patients were studied in the stabilized phase of the disease as a follow up to the rehabilitation process. The study was designed to compare results with a normal, able bodied population and to investigate if any abnormal finding could be related to the age at onset of the spinal cord injury, the duration of the disease or the level of the lesion. Compared to the normal, able bodied population, this study indicates that patients with a spinal cord injury do not have higher levels of cholesterol or LDL, nor lower levels of HDL. Levels of total cholesterol increase with aging, as in the normal population, but have no relation to the duration of the disease or the level of the lesion. Blood levels of HDL and LDL do not seem to be related either to the duration of the disease or to the level of the lesion.

Modulation of TXA2 generation of platelets by human lipoproteins

The lipoprotein (LP) fractions VLDL, LDL, HDL2 and HDL3 were prepared by ultracentrifugation of plasma from healthy volunteers and from patients with coronary heart disease (CHD). We investigated the capacity of platelets from healthy volunteers and patients with atherosclerosis to generate thromboxane A2 (TXA2) during spontaneous clotting of whole blood under the influence of the lipoprotein fractions. In our experiments the serum concentration of TXB2, reflecting the capacity of platelets to generate TXA2 during clotting, depends on several factors: the type of LP fraction used, the blood used for generation of TXA2, and for the same LP fraction whether it was taken from plasma of healthy volunteers or patients with CHD. VLDL prepared from plasma of healthy volunteers inhibited but VLDL prepared from plasma of patients with CHD enhanced the TXA2 formation of platelets from healthy volunteers (p less than 0.05, resp.). LDL from CHD patients inhibited the TXA2 formation of platelets from atherosclerotic patients (p less than 0.01). The HDL subfractions HDL2 and HDL3 from healthy volunteers inhibited TXA2 formation by platelets from healthy volunteers as well as those from atherosclerotic patients (p less than 0.05; p less than 0.01, respectively). HDL2 from patients with CHD inhibited only the TXA2 formation of platelets from healthy volunteers (p less than 0.01), whereas HDL3 from CHD patients inhibited only the TXA2 formation of platelets from atherosclerotic patients (p less than 0.01).

Investigation of lipid transfer in human serum leading to the development of an isotopic method for the determination of endogenous cholesterol esterification and transfer

The rate at which radioactivity appeared in cholesteryl esters (CE) in whole serum and in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) when radioactively labelled free cholesterol (FC) was incubated with serum was investigated. At 4 degrees C equilibration of radioactive FC with native FC occurred, but there was no conversion to CE. At 37 degrees C CE mass increased in parallel with radioactivity in CE both in whole serum and VLDL/LDL. Incubation at 37 degrees C with an inhibitor of lecithin cholesterol acyl transferase (LCAT) abolished the increase in the total CE radioactivity and mass in serum. Transfer of CE from high density lipoprotein (HDL) to VLDL/LDL, however, continued to occur. An assay for LCAT and for cholesteryl ester transfer protein (CETP) was developed, which employed the increases in radioactive CE in whole serum and VLDL/LDL during a single incubation as indices of LCAT and CETP activity, respectively. Determination of the initial serum FC concentration allowed the expression of these activities in nmol/ml per h. References ranges were established in 62 fasting normolipidaemic men and women and increases in both LCAT and CETP were found following a fatty meal. The experiments thus provided further information about the carrier-mediated transfer of CE from its site of esterification on HDL to VLDL/LDL and formed the basis of a relatively simple assay, which has advantages over previously published methods and which may be used in clinical and epidemiological studies to elucidate the role of CETP and LCAT in atherosclerosis.

Serum cholesterol binding reserve percentage in diabetes mellitus

Serum cholesterol binding reserve percentage (SCBR%) in patients with diabetes mellitus (22.17 +/- 13.40%) was significantly lower than in controls (40.93 +/- 8.69%) (p less than 0.001). SCBR% of controls did not vary with age (age range 20-80 years). SCBR% declined significantly with increasing duration of diabetes. It also decreased with macrovascular complications and was lowest in multiple/fatal complications further corroborating the value of SCBR% as a risk indicator of atherogenesis. The relationship of SCBR% with treatment was very striking. All adequately controlled patients had a significantly higher SCBR% than those who were poorly controlled regardless of treatment modality and those adequately controlled on insulin had the highest SCBR%, which was close to that of normal controls.

Increased serum triacylglycerol and cholesterol binding reserve in acute uremic rats

In acute uremic rats (24 h after bilateral nephrectomy, serum urea 280-300 mg/dl) the interface tension of the serum is significantly reduced. Serum levels of triacylglycerol are significantly elevated in uremia, whereas cholesterol levels do not show a significant alteration. The in vitro serum binding reserve for both, triacylglycerol and cholesterol is considerably enhanced. These results let suppose the presence of tenside-like substances in uremic serum which may be involved in disturbed triacylglycerol transport from the serum to the tissues and in development of uremic hypertriglyceridemia.

High density lipoprotein levels in children of young men with ischaemic heart disease

This study was designed to assess HDL levels in children of young men with IHD, compared with children of asymptomatic men. Like their fathers, sons of patients with heart disease, had significantly lower HDL cholesterols than controls. This difference was independent of fasting triglycerides, obesity, diet or physical activity, and was the only "coronary risk factor" in this young age group.

Effects of steroids on serum lipids and serum cholesterol binding reserve

Serum cholesterol binding reserve (SCBR) denotes the capacity of serum to solubilize additional cholesterol. It as been shown previously that a decrease of the SCBR in the presence of elevated cholesterol and/or triglyceride levels is associated with the development of coronary artery disease in man. This is a preliminary report of the effect on serum lipids and SCBR by alteration of the sex steroid environment in women. The hormonal changes associated with pregnancy appear to elevate cholesterol, triglycerides, and SCBR, SCBR being elevated to the greatest extent. No differences were observed in SCBR and serum lipids in a short-term study of premenopausal women when values prior to castration are compared with values after castration during administration of conjugated equine estrogens. In women observed over a period of over 20 weeks, who were using a combination oral contraceptive pill with 1 mg. of norethindrone and 50 or 80 mcg. of mestranol, there was a significant elevation of triglycerides, some decrease of cholesterol, and no change in the SCBR. The possible significance of these findings in relation to the risk of coronary heart disease deserves further investigation.

High density lipoproteins in ischaemic heart disease

High density lipoprotein cholesterol concentrations were significantly lower in ischaemic heart disease patients than in healthy subjects when age and sex-matched. This difference was, however, not observed in the older age group (greater than 60 years).

Plasma high-density lipoprotein concentrations in chronic-hemodialysis and renal-transplant patients

Since epidemiologic studies show that the risk of clinically evident atherosclerosis correlates negatively with concentrations of high-density lipoprotein, we sought to determine whether patients on chronic hemodialysis or recipients of renal transplants had alterations in this lipoprotein similar to those described in other disorders associated with accelerated forms of atherosclerosis. High-density-lipoprotein cholesterol concentrations in both groups of renal patients were significantly lower than control values (P less than 0.01), and their ratios of low-density-lipoprotein to high-density-lipoprotein cholesterol were significantly higher (P less than 0.01) than those observed in both randomly selected controls and in controls matched for plasma lipid levels (control, 2.4 +/- 1.2, dialysis, 3.7 +/- 2.1, and transplant, 5.4 +/- 2.3 mg per 100 ml [mean +/- S.D.]) if, as experimental evidence suggests, high-density lipoprotein retards the development of atherosclerosis, and low-density lipoprotein has opposite effects, the higher ratio of low-density-lipoprotein to high-density-lipoprotein cholesterol found in chronic-dialysis and renal-transplant patients may be related to their premature morbidity and mortality from cardiovascular causes.

High-density-lipoprotein cholesterol and other serum lipids in a New Zealand biracial adolescent sample. The Wairoa College survey

Among New Zealand adolescents, Maoris have lower serum high-density-lipoprotein cholesterol levels and higher serum triglyceride levels than non-Maoris. Boys have lower high-density-lipoprotein cholesterol and triglyceride levels than girls. Low-density-lipoprotein cholesterol levels do not show sex/race differences. These findings are reflected in an excess of hyperlipidaemia type IV in Maori girls. There may be a relation between these lipid distributions and the excess Maori mortality, especially among females, from ischaemic heart-disease.

The Tromsø heart-study. High-density lipoprotein and coronary heart-disease: a prospective case-control study

The relationship of future clinical coronary heart-disease (C.H.D.) to the plasma-high-density-lipoprotein (H.D.L.)-cholesterol concentration has been examined in a 2-year case-control follow-up study of 6595 men aged 20-49 years living in the municipality of Tromsø, Norway. Measurements were also made of the cholesterol concentration in lower-density (i.e., density less than 1-603 g/ml) lipoproteins, plasma-triglycerides, systolic and diastolic blood-pressures, relative body-weight, and cigarette consumption. Discriminant-function analysis showed that coronary risk was inversely related to H.D.L.-cholesterol concentration and directly related to density less than 1-063 cholesterol. These relationships were independent of each other and of the other measured variables, which showed no significant differences between the cases and controls. H.D.L. cholesterol made a three-fold greater contribution to the prediction of future C.H.D. than did density less than 1-063 cholesterol in this cohort of young men. These findings support the proposal that a low H.D.L. concentration is a common antecedent of clinical C.H.D. and is important in accelerating the progression of coronary atherosclerosis.

Serum-high-density-lipoprotein and atherosclerotic heart-disease

Serum-high-density-lipoprotein (H.D.L.) concentrations were determined in 49 men who had had a myocardial infarction and in 102 healthy, middle-aged men, all from Northern Sweden. A quantitative immunological assay based on a monospecific antiserum to the main polypeptide (apoprotein A-I) of H.D.L. was used. The mean H.D.L. concentration was significantly lower in the men with coronary heart-disease than in the controls. The results accord with the hypothesis that high levels of H.D.L. to some extent protect against ischaemic heart-disease.