[Imaging of early carotid artery atherosclerotic lesions with 111In-labeled polyelonalhuman IgG (HIG)]

AIM

To assess the value of scintigraphy with 111In-HIG for diagnosis and evaluation of the stage and the clinical extent of carotid artery disease in humans a prospective clinical comparative trial of scintigraphy vs. sonography was performed.

METHODS

58 patients (38 male, 20 female; mean age 60 +/- 7 years) with hyperlipidemia and ultrasonographically detectable carotid artery lesions were studied. After i.v. injection of 18.5 MBq 111In-HIG, anterior scintigraphic images of the neck were acquired. Real time two-dimensional B-mode ultrasonography of the left and the right carotid arteries was performed.

RESULTS

111In-HIG-scintigraphy as compared to the morphological gold standard (ultrasonography) had a sensitivity of 70-73%, specificity of 33-41% and a positive predictive value of 77-82% for detecting carotid atherosclerotic lesions. There was, however, no significant correlation between scintigraphy and ultrasonography.

CONCLUSION

However, the data provide evidence that the two imaging techniques are visualizing different aspects of atherogenesis. On the one hand a functional one reflecting the activity of the disease (111In-HIG) and on the other hand the morphological one resembling the extent of the disease (ultrasonography).

Cholesteryl ester transfer protein gene polymorphism is a determinant of HDL cholesterol and of the lipoprotein response to a lipid-lowering diet in type 1 diabetes

The TaqIB cholesteryl ester transfer protein (CETP) gene polymorphism (B1B2) is a determinant of HDL cholesterol in nondiabetic populations. Remarkably, this gene effect appears to be modified by environmental factors. We evaluated the effect of this polymorphism on HDL cholesterol levels and on the lipoprotein response to a linoleic acid-enriched, low-cholesterol diet in patients with type 1 diabetes. In 44 consecutive type 1 diabetic patients (35 men), CETP polymorphism, apolipoprotein (apo) E genotype, serum lipoproteins, serum CETP activity (measured with an exogenous substrate assay, n = 30), clinical variables, and a diet history were documented. The 1-year response to diet was assessed in 14 type 1 diabetic patients, including 6 B1B1 and 6 B1B2 individuals. HDL cholesterol was higher in 10 B2B2 than in 14 B1B1 homozygotes (1.63 +/- 0.38 vs. 1.24 +/- 0.23 mmol/l, P < 0.01). HDL cholesterol, adjusted for triglycerides and smoking, was 0.19 mmol/l higher for each B2 allele present. CETP activity levels were not significantly different between CETP genotypes. Multiple regression analysis showed that VLDL + LDL cholesterol was associated with dietary polyunsaturated:saturated fatty acids ratio (P < 0.02) and total fat intake (P < 0.05) in the B1B1 homozygotes only and tended to be related to the presence of the apo E4 allele (P < 0.10). In response to diet, VLDL + LDL cholesterol fell (P < 0.05) and HDL cholesterol remained unchanged in 6 B1B1 homozygotes. In contrast, VLDL + LDL cholesterol was unaltered and HDL cholesterol decreased (P < 0.05) in 6 B1B2 heterozygotes (P < 0.05 for difference in change in VLDL + LDL/HDL cholesterol ratio). This difference in response was unrelated to the apo E genotype. Thus, the TaqIB CETP gene polymorphism is a strong determinant of HDL cholesterol in type 1 diabetes. This gene effect is unlikely to be explained by a major influence on the serum level of CETP activity, as an indirect measure of CETP mass. Our preliminary data suggest that this polymorphism may be a marker of the lipoprotein response to dietary intervention.

Effects of training and a single session of exercise on lipids and apolipoproteins in hypercholesterolemic men

To differentiate between transient (acute) and training (chronic) effects of exercise at two different intensities on blood lipids and apolipoproteins (apo), 26 hypercholesterolemic men (cholesterol = 258 mg/dl, age = 47 yr, weight = 81.9 kg) trained three times per week for 24 wk, 350 kcal/session at high (80% maximal O2 uptake, n = 12) or moderate (50% maximal O2 uptake, n = 14) intensity. Serum lipid and apolipoprotein (apo) concentrations (plasma volume adjusted) were measured before and immediately, 24, and 48 h after exercise on four different occasions corresponding to 0, 8, 16, and 24 wk of training. Data were analyzed using three-way repeated-measures multivariate analysis of variance followed by analysis of variance and Duncan's procedures (alpha = 0.05). A transient 6% rise in low-density-lipoprotein cholesterol measured before training at the 24-h time point was no longer evident after training. Triglycerides fell and total cholesterol, high-density-lipoprotein cholesterol (HDL-C), HDL3-C, apo A-I, and apo B rose 24-48 h after exercise regardless of training or intensity. Total cholesterol, HDL3-C, apo A-I, and apo B were lower and HDL2-C was higher after training than before training. Thus exercise training and a single session of exercise exert distinct and interactive effects on lipids and apolipoproteins. These results support the practice of training at least every other day to obtain optimal exercise benefits.

Evidence for the anti-hyperlipidaemic activity of the edible fungus Pleurotus ostreatus

The effects are described of adding either the dried fruiting bodies of the oyster fungus Pleurotus ostreatus, or an ethanolic extract of it, to the diet of normal Wistar male rats and a strain with hereditary hypercholesterolaemia. Addition of the dry oyster fungus to the diet significantly increased, by more than two-fold, the triacylglycerol (TAG) level in the plasma of both groups of rats compared with their respective controls. In contrast, the ethanolic extract did not significantly change TAG levels. Values for total cholesterol and its high- and low-density lipoprotein fractions in the plasma, as well as the calculated atherogenic index, did not show any significant change. Levels of liver cholesterol were significantly lowered by the dried oyster fungus in both hypercholesterolaemic and normal groups of rats, and by the ethanolic extract in normal rats. A significantly increased phospholipid-to-cholesterol ratio in the aortas of both groups of rats, after the administration of either dried oyster fungus or the ethanolic extract of it, suggests a favourable anti-atherogenic effect for both.

Essential hypertension and 5' upstream core promoter region of human angiotensinogen gene

The angiotensinogen (AGT) gene M235T variant is associated with essential hypertension and elevated plasma AGT concentrations, although the underlying mechanisms are unknown. Recent studies have suggested that AGCE 1 (human AGT gene core promoter element 1) located in the 5' upstream core promoter region (position -25 to -1) of the human AGT gene has an important part in the expression of AGT mRNA by binding with transcription factor AGCF 1 (human AGT gene core promoter element binding factor 1), and a mutation at -20 from adenine to cytosine (A-20C) increases the level of expression of this transcript. We therefore examined subjects with this mutation to study the association with increased plasma AGT concentrations and with essential hypertension. One hundred eighty-eight subjects receiving no antihypertensive medication were examined with regard to the correlation between A-20C and plasma AGT concentrations, and 234 subjects were studied with respect to the association between A-20C and essential hypertension. A-20C was determined by polymerase chain reaction-restriction fragment length polymorphism analysis with EcoOR 109I. Multiple regression analysis showed a weak but significant correlation between A-20C and plasma AGT concentrations (P=.047) and essential hypertension (P=.049). The results suggest that A-20C may underlie the increase in plasma AGT concentrations and be involved in the development of essential hypertension.

Increased serum GHBP levels in obese pubertal children and adolescents: relationship to body composition, leptin and indicators of metabolic disturbances

OBJECTIVE

The serum concentration of the high-affinity growth hormone-binding protein (GHBP) is increased in obesity but the mechanisms are poorly understood. This study assessed the physiological mechanisms involved in the regulation of GHBP in adiposity.

SUBJECTS AND MEASUREMENTS

We tested a number of obesity specific parameters for their association with GHBP. In this study, 199 normal or overweight children and adolescents (101 boys, 98 girls, aged (mean +/- s.d.): 13.7 +/- 2.3 y) underwent an anthropometric evaluation (circumference measurements and bioimpedance analysis) combined with blood withdrawal for the measurement of insulin-like growth factor-I (IGF-I), insulin, leptin and GHBP (by specific RIA), uric acid, triglycerides and cholesterol.

RESULTS

By linear regression analysis GHBP correlated significantly (P < 0.001) with percent body fat mass (r = 0.71), waist (r = 0.73) and hip (r = 0.69) circumference, weight (r = 0.61) waist hip ratio (WHR) (r = 0.54), as well as with the serum concentrations of leptin (r = 0.64), uric acid (r = 0.54), insulin (r = 0.45), LDL-cholesterol (r = 0.43), cholesterol (r =0.33), LDL/HDL ratio (r = 0.47), triglycerides (r = 0.30) and with height standard deviations scores (SDS) (r = 0.23). Age, gender and pubertal stage had no impact on GHBP. In a multiple regression analysis containing age and gender, as well as the anthropometric variables, percent fat mass and waist circumference, as independent variables, associations between GHBP and leptin (P < 0.001), cholesterol (P < 0.01), LDL-cholesterol (P = 0.01), LDL/HDL ratio (P = 0.02), triglycerides (P = 0.01) remained significant. In a final model using the stepwise analysis involving age, gender and all the independent predictors of GHBP, waist circumference (P < 0.001), accounted for 49.5% of the 60.0% total variability in GHBP, while the implication of leptin (P < 0.001), age (P < 0.01) and cholesterol (P < 0.05) increased the predicted variability for 7.5%, 1.9%, and 1.0%, respectively. Serum GHBP was significantly reduced in a subgroup of 104 overweight or obese patients during a diet-induced weight loss programme, the coefficient of correlation between GHBP and leptin after (r = 0.45, P < 0.001) and before weight reduction (r = 0.41, P < 0.001) were comparable.

CONCLUSION

Waist circumference, an indicator of abdominal body fat mass, is a major determinant of GHBP levels during childhood, while leptin may be one candidate for a signal linking adipocytes to the growth hormone receptor related GHBP release. Additionally, elevated serum levels of GHBP may reflect metabolic disturbances of adiposity.

Sensitization to insulin induced by beta,beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) in obese Zucker rats in vivo

Beta,beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) consists of a nonmetabolizable long-chain fatty acid designed to probe the effect exerted by fatty acids on insulin sensitivity. The effect of MEDICA 16 was evaluated in insulin-resistant Zucker (fa/fa) rats in terms of liver, muscle, and adipose tissue response to clamped euglycemic hyperinsulinemia in vivo. Nontreated Zucker rats were insulin resistant, maintaining basal rates of total-body glucose disposal, glucose production in liver, free fatty acid (FFA) flux into plasma, and FFA reesterification in adipose tissue, irrespective of the insulin levels induced. MEDICA 16 treatment resulted in an insulin-induced decrease in hepatic glucose production, together with an insulin-induced increase in total-body glucose disposal. Intracellular reesterification of lipolysed FFA in adipose tissue was specifically activated by MEDICA 16, resulting in a pronounced decrease in FFA release, with a concomitant decrease in plasma FFA. In conclusion, MEDICA 16 treatment results in the sensitization of liver, muscle, and adipose tissue to insulin in an animal model for obesity-induced insulin resistance.

A double-blind, randomized, controlled trial of the effects of two eggs per day in moderately hypercholesterolemic and combined hyperlipidemic subjects taught the NCEP step I diet

OBJECTIVE

We investigated the effect of egg feeding in 161 hypercholesterolemic (HC) or combined hyperlipidemic (CHL) free-living subjects taught the NCEP Step I Diet.

METHODS

Subjects had LDL-C between 3.36 and 4.91 mmol/L (130 and 190 mg/dL). HC subjects had triglyceride concentrations < 75th %-ile, CHL > or = 75th %-ile. Six weeks after instituting the Step I Diet, subjects were randomized to two eggs or egg substitute daily for 12 weeks.

RESULTS

Mean dietary intake (9-day food records) was within NCEP guidelines and 131 subjects finished with stable weight and adherence > 80%. Placebo group lipoprotein lipids were unchanged at study end for both HC (n = 35) and CHL (n = 21) subjects. Egg-fed HC subjects (n = 44) increased LDL-C nonsignificantly, 0.07 mmol/L (3 mg/dL) (p = 0.49). Egg-fed CHL subjects (n = 31) increased LDL-C 0.31 mmol/L (12 mg/dL) (p < 0.001). HDL-C increased significantly in both HC and CHL groups, 0.10 and 0.08 mmol/L (4 and 3 mg/dL, p = 0.003 and 0.02), respectively. HC and CHL subjects did not differ by apo E phenotype distribution. Postprandial triglyceride-rich lipoproteins and LDL subclass phenotype were unaffected by egg feeding in subsets of subjects.

CONCLUSIONS

CHL subjects ingesting a Step I Diet in a free-living setting are sensitive to egg feeding and should benefit from dietary cholesterol restriction. The limited LDL-C rise in HC subjects resembles that seen in egg-fed normocholesterolemic subjects ingesting a Step I Diet, but requires confirmation.

Cardiovascular risk factors in people with different genotypes in the insertion/deletion (I/D) polymorphism at the locus for angiotensin I-converting enzyme (ACE)

The deletion (D) allele of an insertion/deletion (I/D) polymorphism at the locus for angiotensin I-converting enzyme (ACE) has been reported to be an independent risk factor for myocardial infarction (MI), particularly in people lacking traditional risk factors. Furthermore, a borderline association between Lp(a) lipoprotein level and the I/D polymorphism at the ACE locus was reported in one study. We have searched for possible "level gene" or "variability gene" effects of ACE genes on Lp(a) lipoprotein, total cholesterol (TC), high density lipoprotein (HDL) cholesterol (HDLC), low density lipoprotein (LDL) cholesterol (LDLC), triglycerides (TG), apolipoprotein B (apoB), apolipoprotein A-I (apoA-I), and body mass index (BMI). None of these variables differed significantly between genotypes in the I/D polymorphism in any of three population samples. A single population sample created by combining the three series, exhibited an insignificant trend towards individuals carrying the D-allele having a higher level of Lp(a) lipoprotein than those lacking it, and DD homozygotes had a significantly higher Lp(a) lipoprotein level than the combined group of ID/II individuals (p = 0.03). These results may indicate that the D-allele of the I/D polymorphism at the ACE locus could influence the level of Lp(a) lipoprotein.

Effects of ethyl-all-cis-5,8,11,14,17-icosapentaenoate (EPA-E), pravastatin and their combination on serum lipids and intimal thickening of cuff-sheathed carotid artery in rabbits

The anti-arteriosclerotic effects of ethyl all-cis-5, 8, 11, 14, 17-icosapentaenoate (EPA-E), pravastatin and their combination in cuff-treated rabbits were investigated. EPA-E at 600 mg/kg, pravastatin at 50 mg/kg or their combination was orally administered once daily for 5 weeks, and each of the animals was sheathed with a cuff on the carotid artery 2 weeks after the beginning of drug administration. EPA-E, pravastatin and their combination significantly reduced serum total cholesterol compared to the control group. EPA-E also potently reduced serum triglyceride, while pravastatin only slightly reduced it. The combination of these two agents had the most potent effect on the level of serum triglyceride. Serum phospholipids were also reduced by these treatments in a similar fashion. At the end of treatment, diffuse intimal thickening was observed in the cuff-covered region in all animals in the control group, and the intima/media area ratio in this group was 0.293 +/- 0.038. Treatment with EPA-E alone tended to prevent the intimal thickening, and the intima/media area ratio was 0.209 +/- 0.058 (p = 0.094). This ratio was 0.287 +/- 0.048 (p = 0.902) when pravastatin was administered alone, indicating that it had no significant effect on intimal thickening. The ratio was 0.175 +/- 0.041 (p = 0.042) when both EPA-E and pravastatin were administered, indicating that this combination had a significant inhibitory effect on intimal thickening in the cuff-sheathed region. These findings suggest that combined treatment with EPA-E and pravastatin is more effective than respective monotherapies in lowering serum lipids and/or preventing an intimal thickening as events of atherogenesis.

Polyenylphosphatidylcholine decreases alcoholic hyperlipemia without affecting the alcohol-induced rise of HDL-cholesterol

In ethanol-fed rats, supplementation of the diet with soybean polyenylphosphatidylcholine (3 g/liter for 21 days) markedly decreased postprandial VLDL-triglycerides and both VLDL- and LDL-cholesterol levels, whereas it maintained high levels of HDL-cholesterol, compared to an equivalent intake of choline and polyunsaturated fatty acids. By contrast, there were no changes in the serum lipoproteins of the pair-fed controls. The prevention of alcoholic hypertriglyceridemia was associated with marked attenuation of the alcoholic fatty liver and it occurred despite a slight increase in fat absorption. Thus, the administration of polyenylphosphatidylcholine not only attenuates the hepatotoxicity of ethanol, but also increases the HDL/LDL cholesterol ratio, which may be beneficial for the prevention of atherosclerosis and coronary heart disease.

Transient triglyceridemia decreases vascular reactivity in young, healthy men without risk factors for coronary heart disease

BACKGROUND

Hypertriglyceridemia is now accepted as a risk factor for coronary heart disease, although the mechanism behind the increased risk is not well understood. The present study was undertaken to investigate the effects of triglyceridemia on endothelial function, because impaired endothelial function is considered a marker of atherogenesis.

METHODS AND RESULTS

Flow- and nitroglycerin-induced dilatation of the brachial artery was investigated noninvasively by high-resolution ultrasound technique in seven young, healthy men without risk factors for coronary heart disease. Transient triglyceridemia was induced by infusion of a triglyceride emulsion, Intralipid, which raised free fatty acid concentrations twofold and triglyceride levels fourfold. Flow-induced vasodilatation decreased from 7.1+/-3.0% to 1.6+/-2.6% (P<.0002), whereas nitroglycerin-induced vasodilatation decreased from 20.5+/-5.8% to 11.5+/-3.2% (P<.002) before and after 1 hour of infusion of Intralipid, respectively.

CONCLUSIONS

Transient triglyceridemia decreases vascular reactivity, presumably by both endothelium-dependent and endothelium-independent mechanisms.

Influence of macrophage-derived apolipoprotein E on plasma lipoprotein distribution of apolipoprotein A-I in apolipoprotein E-deficient mice

High density lipoprotein (HDL) cholesterol in apolipoprotein (apo) E-deficient mice is decreased. It has been suggested that apoA-I is lost from HDL in these mice because it must substitute for apoE as a structural protein for the abnormal cholesterol-rich lipoproteins. Therefore, we examined in vivo the influence of selective apoE expression on plasma HDL cholesterol in apoE-deficient mice. Bone marrow transplantation was used to establish macrophage-specific expression of apoE. Bone marrow transplantation normalized plasma triglycerides and significantly reduced total plasma cholesterol, but it did not increase hepatic apoA-I mRNA levels or total plasma apoA-I. Although total plasma apoA-I was not increased, HDL cholesterol measured following chromatographic separation was elevated twofold. Furthermore, plasma apoA-I was recovered from this HDL in animals expressing macrophage apoE. Compared to HDL of wildtype mice, this HDL had a similar chromatographic size distribution, but it lacked apoE and was more negatively charged. These studies indicated that plasma apoA-I distribution and HDL composition are influenced by apoE and that the abnormal apoA-I lipoprotein distribution of apoE-deficient mice can be altered in vivo by macrophage-derived apoE.

Physically active women demonstrate less adverse age-related changes in plasma lipids and lipoproteins

The results of this study support the hypothesis that women who exercise regularly have less adverse changes in plasma lipids and lipoproteins with age than sedentary women. This may contribute to the smaller age-related increase in the incidence of coronary heart disease observed in physically active women.

Lipid profile during hormone replacement therapy: effect of different progestins?

Oral estrogens cause a decrease of low density lipoprotein cholesterol (LDL-chol.) and, especially an increase of high density lipoprotein cholesterol (HDL-chol.) levels, which both have potentially favorable effects; they also cause a triglyceride level increase, which probably has no clinical relevance except in cases with basal hypertriglyceridemia. Transdermal estradiol causes generally a minor decrease in LDL-chol. and minor increase HDL-chol. levels, with no increase or even decrease in triglyceride levels. The addition of androgenic progestins at conventionally used doses, while not interfering with LDL-chol. variations, causes a HDL-chol. decrease, which contrasts the effect of oral estrogens and completely reverses the effect of transdermal estradiol. On the contrary, the addition of a non androgenic progestin does not interfere with any of the estrogen induced lipid profile modifications.

Platelet hypoaggregability in hereditary hypertriglyceridemic rats: relation to plasma triglycerides

To define better the relationships between lipid metabolism disturbances and platelet aggregation we have examined these parameters in hereditary hypertriglyceridemic and control Lewis rats. Hereditary hypertriglyceridemic rats are hypertensive and have high plasma triglycerides but not elevated plasma total cholesterol. In the present study, we have demonstrated that platelets from hereditary hypertriglyceridemic rats have lowered initial rate and maximal aggregation after stimulation with thrombin or ADP in comparison with controls. These two strains did not differ significantly in the inhibition of platelet aggregation by the thromboxane A2 receptor inhibitor, SQ 29 548. In hereditary hypertriglyceridemic rats, the thrombin response, as well as the contribution of the thromboxane A2-sensitive pathway, were positively associated with the plasma level of triglycerides. Similar trend was found in Lewis rats. However, the slopes of these relationships were reduced in hereditary hypertriglyceridemic rats. These alterations of the aggregatory responses in hereditary hypertriglyceridemic rats were independent of blood pressure and plasma cholesterol level. In conclusion, our results showed a clear-cut platelet hypoaggregability to both thrombin and ADP in hypertensive hypertriglyceridemic rats. This hypoaggregability was not due to an impaired function of the thromboxane A2 pathway but could be connected with disturbances of lipid metabolism.

Comparison of aging and hypercholesterolemic effects on the sodium inward currents in cardiac myocytes

To study and to compare the hypercholesterolemic and aging effect on the sodium inward currents (I(Na)) in cardiac myocytes, whole-cell clamp recordings were made in single cardiac myocyte isolated from normo- and diet-induced hypercholesterolemic rabbits of different age groups. The cell capacitance of adult and hyperlipidemic myocytes seemed larger than that of young and normolipidemic ones. However, the sodium current density at a holding potential of -80 mV on adult and hypercholesterolemic ventricular sarcolemma was significantly lower than that on young and normolipidemic one (adult hyperlipidemic: -15.3+/-2.4 pA/pF (n=16), adult control: -28.1+/-3.4 pA/pF (n=13), young hyperlipidemic: -39.5+/-5.4 pA/pF (n=19), young control: -67.3+/-7.8 pA/pF (n=12)). In aging process, this effect was due to a decrease in channel number, a leftward shift in the inactivation potential and a slowing of the time course of recovery. In hypercholesterolemia, however, the major cause was due to the functional change of sodium currents. In addition to decreasing the sodium current magnitude, hypercholesterolemia lowered the threshold for excitation of cardiac myocytes (-50 mV vs -40 mV). In conclusion, aging process depressed the sodium channel activity in ventricular myocytes. In addition to inducing some similar functional alterations of I(Na) as aging process, long-term hypercholesterolemia could also increase the excitability in cardiac myocytes, which was different from aging process.

The effect of change of renal replacement therapy on serum lipoprotein (a) concentration

Lipoprotein (a) [Lp(a)] is an independent atherogenic risk factor. Lp(a) levels are elevated in patients on renal replacement therapy (RRT). This study looked at the effect of change of RRT on serum lipid and Lp(a) levels. Three groups were identified: (1) patients on dialysis who were transplanted; (2) those who had lost their transplants through immunorejection; (3) those who changed from continuous ambulatory peritoneal dialysis (CAPD) to hemodialysis (HD). All Lp(a) measurements were taken at least 3 months after the change of therapy. Our results were as follows: Group A (n = 21): 8 CAPD and 13 HD patients were transplanted. Median Lp(a) levels fell posttransplantation in the CAPD group (15.6 mg/dL vs 11.4 mg/dL, p = 0.04). The HD group showed a rise in cholesterol, low-density (LDL) and high-density lipoprotein (HDL) levels, with no change in Lp(a) levels. Group B (n = 11): 7 patients started CAPD and 4 HD. Overall, there was a marked increase in Lp(a) levels: median 38.2 mg/dL vs 55.9 mg/dL (p = 0.04), reflecting an increase in those starting CAPD (27.8 mg/dL vs 60.0 mg/dL, p = 0.01), with little change in the HD group (40.45 mg/dL vs 40.05 mg/dL). However, there was a decrease in cholesterol (7.4 mmol/L vs 5.1 mmol/L, p = 0.002) and LDL (5.5 mmol/L vs 3.3 mmol/L, p = 0.004). Group C (n = 16): 16 patients changed from CAPD to HD. Lp(a) levels were higher while on CAPD, as compared to when on HD (58.9 mg/dL vs 49 mg/dL, p = 0.03). Cholesterol (6.62 mmol/L vs 5.26 mmol/L, p = 0.006) and LDL (4.48 mmol/L vs 3.40 mmol/L, p = 0.004) were also higher when on CAPD. In conclusion, serum Lp(a) levels are clearly affected by the mode of the RRT, being highest in CAPD, and decline after transplantation or conversion to HD. Atherogenic risk is thus likely to differ between the modes of RRT and may be greatest for those on CAPD.

Apolipoproteins in obesity: effect of weight loss

We evaluated serum concentrations of apoprotein (APO) A1, B, total cholesterol, triglycerides, high density cholesterol (HDL-C), and low density cholesterol (LDL-C) in twelve obese subjects whose body mass index (BMI) was > or = 30 before and after a clinically significant weight loss was obtained utilizing a very-low calorie diet (VLCD) consisting of liquid protein (Optifast) providing 800 calories a day. At baseline, the mean weight +/- SD was 119.77 Kg and decreased significantly to 89.29 +/- 13.46 Kg by 24 weeks. Statistically significant reductions of APO-A1, APO-B, total cholesterol, and triglyceride concentrations were also observed along with the weight loss. LDL-C decreased from 156.0 +/- 55.9 mg/dL to 122.5 +/- 42.2 mg/dL (4.03 +/- 1.4 to 3.16 +/- 1.1 mmol/L), but this difference was not statistically significant. There was no significant change in the HDL-C and the ratios of APO-A1 to APO-B. We conclude that the use of VLCD is associated with changes in the lipid pattern that lower the cardiovascular risk profile in addition to the beneficial effects of weight loss itself.

Comparative study of oral and parenteral administration of sho-saiko-to (xiao-chaihu-tang) extract on D-galactosamine-induced liver injury in rats

The preventive effect of Sho-saiko-to (Xiao-Chaihu-Tang) extract (TJ-9) on the progression of D-galactosamine (GaIN)-induced liver injury was examined in five week-old male Wistar rats with oral (p.o.) or intraperitoneal (i.p.) administration of the same dose of TJ-9. Rats treated once with GaIN (500 mg/kg body weight, i.p.) received TJ-9 at a dose of 1.0 g/kg body weight (p.o. or i.p.) 2 hours after GaIN treatment at which time an apparent liver injury occurred. Both p.o. and i.p. administration of TJ-9 showed similar significant prevention against the progression of liver injury 24 hours after GaIN injection. Although total protein and albumin concentrations in serum and protein concentration in the liver decreased with the progression of GaIN-induced liver injury, oral or i.p. administration of TJ-9 prevented these decreases in similar degree. However, decreases in serum and liver triglyceride concentration with the progression of liver injury were not attenuated after p.o. or i.p. administration of TJ-9. The activities of liver 5'-nucleotidase and glucose-6-phosphatase, marker enzymes of liver plasma and microsomal membranes, respectively, decreased during the progression of liver injury. A similar preventive effect on the decrease of both enzyme activities was found after p.o. or i.p. administration of TJ-9. These results indicate that the preventive effect on progression of GaIN-induced liver injury by oral or i.p. administration is approximately equal, and that the effect may be through improving the impaired liver protein synthesis and disrupted liver plasma and microsomal membranes in a similar degree.

Long-term cholesterol-lowering effects of 4 fat-restricted diets in hypercholesterolemic and combined hyperlipidemic men. The Dietary Alternatives Study

CONTEXT

The long-term effect of aggressively vs moderately fat-restricted diets has not been studied extensively in free-living subjects with different types of hyperlipidemia.

OBJECTIVE

To compare the cholesterol-lowering effects of 4 levels of dietary fat intake restriction after 1 year.

DESIGN

Randomized, parallel, comparison trial.

SETTING

Male employees of a large industry.

PARTICIPANTS

A total of 444 men had low-density lipoprotein cholesterol (LDL-C) levels above the 75th age-specific percentile. Subjects with triglyceride (TG) levels less than the 75th age-specific percentile were defined as hypercholesterolemic (HC) and those with TG levels at or above the 75th age-specific percentile were defined as combined hyperlipidemic (CHL).

INTERVENTIONS

Hypercholesterolemic subjects were randomized to diets 1, 2, 3, and 4 taught to contain 30%, 26%, 22%, and 18% fat, and the CHL subjects were randomized to diets 1, 2, and 3. All 4 diets were taught to subjects and spouses or partners in 8 weekly 2-hour classes.

MAIN OUTCOME MEASURES

Plasma lipoprotein levels after 1 year.

RESULTS

Fat intake after 1 year declined from a mean of 34% to 36% of energy to 27%, 26%, 25%, and 22% in the 4 HC diet groups and 28%, 26%, and 25% in the 3 CHL diet groups. Mean+/-SD percent LDL-C reductions were 5.3%+/-16.2%, 13.4%+/-12.6%, 8.4%+/-11.2%, and 13.0%+/-15.7% in the HC diet groups and 7.0%+/-16.2%, 2.8%+/-15.8%, and 4.6%+/-13.5% in the CHL diet groups (P<.01 in all but 1 instance). Apoprotein B levels decreased 8.6%, 10.7%, 4.3%, and 5.3% in the HC groups and 14.6%, 11.4%, and 9.9% in the CHL groups (P<.05-.01 in each instance). Triglyceride levels increased significantly in subjects following HC diets 3 and 4, 21.7% and 38.7% (P<.05 and .01), but not in any CHL subjects. High-density lipoprotein cholesterol decreased 2.8% and 3.2% in subjects on HC diets 3 and 4, respectively (P<.05 in both cases).

CONCLUSIONS

After 1 year, moderate restriction of dietary fat intake attains meaningful and sustained LDL-C reductions in HC subjects and apoprotein B reductions in both HC and CHL subjects. More extreme restriction of fat intake offers little further advantage in HC or CHL subjects and potentially undesirable effects in HC subjects.

Short-term metabolic and haemodynamic effects of GR79236 in normal and fructose-fed rats

The adenosine (A1) receptor agonist, GR79236 (N-[(1S,trans)-2-hydroxycyclopentyl]adenosine), inhibits catecholamine-induced lipolysis in vitro, but the short-term metabolic and haemodynamic effects have not been previously reported in the fructose fed model of insulin resistance, dyslipidaemia and hypertension. This study reports the effects of GR79236 (1 mg/kg/day for 8 days) on nonesterified free fatty acid and triglyceride metabolism, oral and i.v. glucose tolerance, blood pressure and heart rate, and insulin sensitivity, in normal rats and rats fed a fructose-enriched diet. In normal rats, GR79236 significantly reduced fasting glucose (25%), free fatty acid (50%) and triglyceride (55%) concentrations, and improved glucose tolerance (AUC[glu] 21.2 +/- 1.3 vs. 16.5 +/- 1.1 mmol h/l, p < 0.05). Fructose feeding induced a state of insulin resistance and dyslipidaemia, as shown by an increase in steady-state plasma glucose levels (7.1 vs. 6.1 mmol/l), impaired i.v. glucose tolerance and a 3-fold rise in fasting triglyceride levels; fructose-fed rats also developed a significant increase in blood pressure. GR79236 ameliorated the effects of fructose feeding on fatty acid and triglyceride levels, and blood pressure, and improved i.v. glucose tolerance in fructose-fed rats. The hypotriglyceridaemic effect was due to a reduction in triglyceride secretion rate (17.3 +/- 1.7 vs. 30.2 +/- 1.1). Thus, in normal rats and in a dietary-induced rodent model of insulin resistance, dyslipidaemia and hypertension, GR79236 has lipid-lowering and glucose-lowering activity, as well as haemodynamic effects, which are potentially useful for treating both the metabolic and haemodynamic features of insulin resistance and NIDDM in humans.

Adenovirus-mediated gene transfer of human lipoprotein lipase ameliorates the hyperlipidemias associated with apolipoprotein E and LDL receptor deficiencies in mice

Lipoprotein lipase (LPL) is the rate-limiting enzyme for the hydrolysis of triglyceride-rich lipoproteins. We tested the efficacy of adenovirus-mediated gene transfer of LPL as treatment of experimental hyperlipidemias associated with apolipoprotein (apoE) deficiency (apoE-/-) and low-density lipoprotein receptor (LDLr) deficiency (LDLr-/-) in mice. Replication-defective adenovirus containing the human LPL cDNA driven by a cytomegalovirus promoter (Ad.hLPL) efficiently transduced CHO-ldlA7 cells in vitro, inducing in these cells the production of bioactive LPL (73 mU/ml). Intravenous injection of Ad.hLPL (2 x 10(9) pfu) led to high-level expression of hLPL mRNA and LPL activity in the liver (88.3 mU/ml) and in post-heparin plasma (116.1 mU/ml). Overexpression of LPL resulted in marked reductions in total plasma cholesterol (TC; 48%, 43%, 25%) and triglycerides (TTg; 63%, 40%, 70%, p < 0.01) in apoE-/-, LDLr-/-, and wild-type (WT) mice, respectively. Fast protein liquid chromatography (FPLC) fractionation of plasma lipoproteins showed a marked decrease in very-low-density lipoprotein (VLDL)/chylomicron remnant cholesterol (V/CR-C) in apoE-/- (83%), LDLr-/- (84%), and WT mice (58%, p < 0.01). VLDL/chylomicron remnant triglycerides (V/CR-Tg) were virtually eliminated in apoE-/- (92%), LDLr-/- (86%), and WT mice (84%, p < 0.05). No significant changes were detected in LPL activities, plasma lipids, or lipoproteins of mice injected with a control virus, Ad.Luc, containing the luciferase instead of the LPL cDNA. In summary, infusion of Ad.hLPL leads to increased liver and post-heparin plasma LPL activities, significantly reduced TC, TTg, V/CR-C, and V/CR-Tg in WT mice, as well as in mice with apoE and LDLr deficiencies. Adenovirus-mediated LPL gene transfer to the liver is an effective means of reversing many of the lipoprotein abnormalities in apoE- and LDLr-deficient mice.

Postprandial hemorrheology and apolipoprotein B metabolism in patients with familial hypertriglyceridemia

Impaired postprandial lipoprotein metabolism has been found to be related to the extent of coronary artery disease. Moreover, since dyslipoproteinemias are associated with impaired hemorrheology, we investigated the effect of postprandial hypertriglyceridemia on hemorrheological parameters before and after triglyceride-lowering therapy. Triglyceride-rich lipoproteins (TRLs) separated by ultracentrifugation (d < 1.006 g/dL) and chylomicrons and chylomicron remnants (quantified by apolipoprotein [apo] B-48 determination) were determined after a fat load in 10 patients with familial hypertriglyceridemia before and after therapy with gemfibrozil (900 mg daily). Lipid and hemorrheological parameters (plasma and whole-blood viscosity [PV and BV], red cell aggregation [RCA], hematocrit, and fibrinogen) were determined at baseline and every hour up to 6 hours postprandially. Fasting total triglycerides and TRL triglycerides significantly decreased with gemfibrozil therapy (P < .01). Total triglycerides postprandially increased from 9.53 +/- 1.72 to 14.47 +/- 2.07 mmol/L (TRL triglycerides by 61%) before therapy (P < .05) and from 4.61 +/- 1.28 to 7.17 +/- 0.99 mmol/L (TRL triglycerides by 57%) after therapy (P < .05). The postprandial TRL apo B increase was reduced with gemfibrozil (from 11.6 +/- 2.8 to 20.7 +/- 5.0 mg/dL with therapy v 19.0 +/- 7.6 to 33.0 +/- 12.5 mg/dL before therapy, P < .05, respectively) with a proportionally greater increase in apo B-48 (119% and 169%, respectively) compared with apo B-100 (64% and 64%, respectively). Fasting RCA was improved with lipid-lowering therapy (P < .05), but PV, BV, RCA, and fibrinogen did not show any statistically significant postprandial changes either before or after lipid-lowering therapy. In summary, we did not find any statistically significant changes in hemorrheological parameters, despite a strong postprandial increase of triglycerides. In particular, these findings were independent of fasting triglyceride levels. We conclude that triglyceride-lowering therapy by gemfibrozil had no substantial beneficial effects with respect to hemorrheology in patients with familial hypertriglyceridemia.

Genetic factors precipitating type III hyperlipoproteinemia in hypolipidemic transgenic mice expressing human apolipoprotein E2

Several factors are hypothesized to precipitate or exacerbate type III hyperlipoproteinemia (HLP) in humans. Among such factors are those that directly overload remnant lipoprotein production or disrupt removal pathways, including an increased ratio of apolipoprotein (apo) E2 to normal apoE, overproduction of apoB-containing lipoproteins, and decreased LDL receptor activity. Hypolipidemic apoE2-transgenic mice bred onto an apoE-null background had dramatically higher plasma total cholesterol (192 +/- 26 mg/dL for males, 203 +/- 40 mg/dL for females) and triglyceride (295 +/- 51 mg/dL for males, 277 +/- 58 mg/dL for females) levels than apoE2 mice with endogenous mouse apoE. Thus, eliminating normal apoE in the presence of apoE2 (thereby increasing the relative abundance of the defective ligand) can convert a hypolipidemic to a hyperlipidemic phenotype. Hypolipidemic apoE2 transgenic mice overexpressing human apoB had moderate remnant accumulation compared with apoE2-only or apoB-only transgenic mice, indicating that overproduction of apoB-containing lipoproteins in the presence of apoE2 can augment remnant production. Hypolipidemic apoE2 transgenic mice bred-onto an LDL receptor-null background had markedly higher plasma total cholesterol (288 +/- 51 mg/dL for males, 298 +/- 73 mg/dL for females) and triglyceride (356 +/- 72 mg/dL for males, 317 +/- 88 mg/dL for females) levels than apoE2-only mice, and remnant accumulation increased even in apoE2 mice with a heterozygous LDL receptor-knockout background (compared with apoE2-only mice), suggesting that reducing or eliminating a major receptor-mediated remnant-removal pathway in the presence of apoE2 can also precipitate a hyperlipidemic phenotype. In all cases where either lipoprotein remnant production or removal pathways were severely stressed, increased remnant accumulation was apparent. As judged by the chemical characteristics of the remnant lipoproteins, the lipoprotein phenotype was quite similar to that of human type III HLP, especially in the apoE2-expressing mice with no endogenous apoE or LDL receptors, and thus these mice represent improved models of the disorder.