Role of deep abdominal fat in the association between regional adipose tissue distribution and glucose tolerance in obese women.

Computed tomography (CT) was used to study the association between adipose tissue localization and glucose tolerance in a sample of 52 premenopausal obese women aged 35.7 +/- 5.5 yr (mean +/- SD) and with a body fat of 45.9 +/- 5.5%. Body-fat mass and the body mass index (BMI) were significantly correlated with plasma glucose, insulin, and connecting peptide (C-peptide) areas after glucose (75 g) ingestion (.40 less than or equal to r less than or equal to .51, P less than .01). Trunk-fat accumulation and the size of fat cells in the abdomen displayed highly significant correlations with postglucose insulin levels. The C-peptide area was also positively correlated with abdominal fat cell size (r = .76, P less than .01) and was more closely associated with the sum of trunk skin folds (r = .59, P less than .001) than with the extremity skin folds (r = .29, P less than .05). Subcutaneous and deep-abdominal-fat areas measured by CT displayed comparable associations with the plasma insulin area (r = .44 and .49, respectively; P less than .001) but marked differences in the associations with glucose tolerance. Indeed, subcutaneous abdominal fat was not significantly correlated with the glucose area, whereas deep abdominal fat showed a significant correlation (r = .57, P less than .001) with the glucose area. Midthigh fat deposition measured by CT was not, however, correlated with plasma glucose, insulin, or C-peptide areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein E polymorphism modifies relation of hyperinsulinemia to hypertriglyceridemia.

The effect of apolipoprotein E polymorphism on the established relationships between glucose tolerance, plasma insulin levels, and plasma lipoprotein concentrations were investigated in a sample of women defined on the basis of apolipoprotein E phenotypes. In women with the apolipoprotein E epsilon 2 allele (n = 22), fasting plasma insulin and glucose and insulin areas under the curve measured during an oral glucose tolerance test were positively correlated with plasma triglyceride levels (0.48 < or = r < or = 0.70; P < 0.05). In this group, very-low-density lipoprotein cholesterol and very-low-density lipoprotein triglyceride concentrations were positively correlated with fasting insulin levels, the insulin area, and with the ratio of insulin area to glucose area. In women (n = 24) homozygous for the apolipoprotein E epsilon 3 allele (the most common allele), essentially similar associations were found. In contrast, in women (n = 17) with the apolipoprotein E epsilon 4 allele, no association was found between glucose tolerance, fasting and postglucose plasma insulin levels, and plasma lipid and lipoprotein levels. These results suggest that apolipoprotein E polymorphism substantially modifies the associations between glucose tolerance, plasma insulin levels, and plasma lipoprotein concentrations. Additional analysis of the data revealed that apolipoprotein E polymorphism did not alter the relationships between body fat distribution and fasting insulin and postglucose insulin levels, but no correlation was observed between fatness indexes and glucose tolerance among apolipoprotein E epsilon 2 carriers.(ABSTRACT TRUNCATED AT 250 WORDS)

Visceral obesity in men. Associations with glucose tolerance, plasma insulin, and lipoprotein levels.

The relations of regional adipose tissue (AT) distribution measured by computed tomography (CT) to plasma insulin-glucose homeostasis and lipoprotein-lipid levels were studied in 58 obese and 29 lean control men. In the group of obese men, the visceral AT area measured by CT was positively correlated with fasting plasma triglyceride and insulin levels and with glucose and insulin areas under the curves measured during a 75-g oral glucose tolerance test. Visceral AT area was also negatively associated with plasma high-density lipoprotein (HDL) and HDL2 cholesterol levels. The relative accumulation of abdominal fat, estimated by the ratio of abdominal to femoral AT areas obtained by CT, was also a significant correlate of indices of carbohydrate metabolism and was the best univariate correlate of plasma lipoprotein levels. No significant associations were observed between the visceral AT area, the ratio of abdominal to femoral AT areas, and indices of carbohydrate and lipoprotein metabolism in the group of lean men. On the other hand, the subcutaneous abdominal AT area was a significant correlate of the glucose area under the curve in both groups of men, but this association was not independent from the percentage of total body fat. No relationship was observed between the femoral AT area and indices of carbohydrate metabolism in either lean or obese groups. In obese men, however, the femoral AT area was negatively correlated with plasma triglyceride concentration and positively correlated with plasma HDL and HDL2 cholesterol levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The apoB-100 gene EcoRI polymorphism influences the relationship between features of the insulin resistance syndrome and the hyper-apoB and dense LDL phenotype in men.

The aim of this study was to investigate whether the EcoRI polymorphism of the apolipoprotein B (apoB) gene influences the relationships between features of the insulin resistance syndrome and the dense LDL phenotype and apoB concentrations. A sample of 65 men was divided into two groups on the basis of the EcoRI genotype. Forty-four subjects were (+/+) homozygotes for the presence of the EcoRI restriction site that is associated with a glutamic acid at codon 4154. Twenty-one men were (+/-) heterozygotes for the absence of the restriction site resulting from a glutamic acid to a lysine substitution at codon 4154. In the (+/-) group, fasting plasma FFA levels were positively correlated with plasma apoB, LDL-apoB, and the LDL particle score that was calculated from the migration distances of LDL subspecies and their relative band intensities, reflecting the proportion of small dense LDL particles. However, these associations were not found among (+/+) subjects. The two genotypic groups were further divided into two subgroups on the basis of fasting FFA concentrations, and the LDL particle score and the LDL-apoB levels were compared. High FFA levels were associated with a higher proportion of small dense LDL particles, as reflected by a higher mean LDL particle score, irrespective of the genotype. However, the apoB-EcoRI polymorphism appeared to influence the association between high FFA levels and LDL-apoB concentrations because (+/-) heterozygotes with high FFA levels had higher LDL-apoB concentrations than (+/-) heterozygotes with low FFA levels. In addition, the integrated area under the curve of plasma insulin concentrations, measured in response to a 75-g oral glucose challenge, and the amount of visceral adipose tissue, measured by computed tomography, were positively associated with the LDL particle score only in (+/-) heterozygotes. When subjects were divided on the basis of insulin area (low vs. high) or visceral adipose tissue (low vs. high), (+/-) heterozygotes with high insulin area or with high levels of visceral adipose tissue had a higher mean LDL particle score than (+/-) heterozygotes with low insulin area or low visceral adipose tissue. However, among (+/+) homozygotes, low or high levels of insulin or visceral adipose tissue could not discriminate between men with large or small LDL particles. Therefore, (+/-) heterozygotes may be more susceptible to develop the dense LDL phenotype in presence of hyperinsulinemia and visceral obesity. Results of the present study suggest that the apoB-EcoRI polymorphism may exacerbate the alterations in the LDL particle (size and concentration) found among visceral obese-hyperinsulinemic men.

Is lipoprotein(a) an independent risk factor for ischemic heart disease in men? The Quebec Cardiovascular Study.

OBJECTIVES: This study was undertaken to determine whether lipoprotein(a) [Lp(a)] is an independent risk factor for ischemic heart disease (IHD) and to establish the relation of Lp(a) to the other lipid fractions. BACKGROUND: Several, but not all, studies have shown that elevated Lp(a) concentrations may be associated with IHD; very few have been prospective. METHODS: A 5-year prospective follow-up study was conducted in 2,156 French Canadian men 47 to 76 years old, without clinical evidence of IHD. Lipid measurements obtained at baseline included total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, apoprotein B and Lp(a). During the follow-up period, there were 116 first IHD events (myocardial infarction, angina, death). Adjusted proportional hazards models were used to estimate the relative risk for the different variables. The cohort was also classified according to Lp(a) levels and other lipid risk factor tertiles to evaluate the relation of elevated Lp(a) levels to these risk factors. A cutoff value of 30 mg/dl was used for Lp(a). Risk ratios were calculated using the group with low Lp(a) levels and the first tertile of lipid measures as a reference. RESULTS: Lp(a) was not an independent risk factor for IHD but seemed to increase the deleterious effects of mildly elevated LDL cholesterol and elevated total cholesterol and apoprotein B levels and seemed to counteract the beneficial effects associated with elevated HDL cholesterol levels. CONCLUSIONS: In this cohort, Lp(a) was not an independent risk factor for IHD but appeared to increase the risk associated with other lipid risk factors.

Leptinemia is not a risk factor for ischemic heart disease in men. Prospective results from the Quebec Cardiovascular Study.

OBJECTIVE: To investigate the possibility that leptin levels may be predictive of the risk of ischemic heart disease (IHD) through the relationship of leptin to body fat. RESEARCH DESIGN AND METHODS: The Quebec Cardiovascular Study cohort consisted of 2,103 French-Canadian men without IHD in 1985 who were followed until 1990, by which time 114 had experienced an IHD event. These 114 men were then individually matched for age, BMI, cigarette smoking, and alcohol intake with 114 subjects who were free of IHD at follow-up. After exclusion of diabetic patients and those in whom leptin levels could not be measured, we were able to compare the initial metabolic profiles of 86 men in the IHD group and of 95 control subjects. RESULTS: Plasma leptin concentrations were positively correlated with BMI (r = 0.67, P < 0.0001) and with fasting insulin concentrations (r = 0.46, P < 0.0001) in the overall sample. These significant associations were also observed when men with IHD and the control subjects were examined separately (control subjects: r = 0.68 for BMI and r = 0.45 for insulin; IHD subjects: r = 0.65 for BMI and r = 0.50 for insulin). With the exception of plasma triglyceride (r = 0.25, P < 0.001), no significant association was found between leptin and plasma lipoprotein and lipid concentrations. Furthermore, plasma insulin remained significantly associated with leptin levels even after adjustment for BMI (r = 0.22, P < 0.005). There was no difference in baseline leptin levels among men who developed IHD versus men who remained IHD-free during the 5-year follow-up (5.56 +/- 3.12 vs. 5.36 +/- 2.90 ng/ml, respectively). Thus, although significantly correlated with the BMI and fasting insulin levels, plasma leptin concentration was not a significant predictor of the 5-year incidence of IHD. This lack of a relationship to IHD was noted when leptin levels were analyzed as tertiles and when leptin concentration was analyzed as a continuous variable. CONCLUSIONS: These prospective results suggest that leptinemia, despite being a strong correlate of obesity, does not appear to be an independent risk factor for the development of IHD in men.

Relation of steroid hormones to glucose tolerance and plasma insulin levels in men. Importance of visceral adipose tissue.

OBJECTIVE: Low plasma testosterone levels are associated with hyperinsulinemia and glucose intolerance in men. However, it is unclear whether these abnormalities are related to the concomitant alteration in regional adipose tissue (AT) accumulation associated with reduced androgen levels. RESEARCH DESIGN AND METHODS: We measured plasma steroid levels in a sample of 79 men, ranging from lean to obese (aged 29-42 years), for whom an oral glucose tolerance test (OGTT), anthropometric and computed tomography (CT) measurements of body fatness, and AT distribution were performed. Sex hormone binding globulin (SHBG) and the following steroids were measured after extraction from plasma and chromatography: dehydroepiandrosterone, androstenedione, androst-5-ene-3 beta,17 beta-diol, testosterone, estrone, and estradiol (E2). RESULTS: Several significant negative correlations were found between adrenal C19 steroid precursors, testosterone, SHBG, and fasting insulin levels, as well as between plasma glucose and insulin concentrations measured during the OGTT (-0.25 < or = r < or = -0.35, 0.05 > or = P > or = 0.001). The best steroid correlate of plasma glucose and insulin homeostasis indexes was the E2: testosterone ratio (0.34 < or = r < or = 0.42, 0.005 > or = P > or = 0.001). However, after correction of steroid levels for either fat mass, body mass index (BMI), or visceral AT area, as measured by CT, no significant residual associations were noted between testosterone, adrenal C19 steroid, SHBG, and estrogen levels and indexes of plasma glucose-insulin homeostasis, although the positive association between the E2: testosterone ratio and glucose area remained significant after adjustment for total body fat mass and BMI. Furthermore, 15 pairs of obese subjects, matched for visceral AT area, showing either low or high levels of the steroids studied, did not differ in fasting insulin and postglucose plasma insulin levels or in glucose tolerance. CONCLUSIONS: These results suggest that the previously reported relationships between androgen levels and indexes of plasma glucose-insulin homeostasis are mediated, to a large extent, by concomitant alterations in levels of total body fat and visceral AT in men.

The dense LDL phenotype. Association with plasma lipoprotein levels, visceral obesity, and hyperinsulinemia in men.

OBJECTIVE: To investigate the potential relationship between the cluster of metabolic abnormalities found in visceral obesity and the small dense LDL phenotype. RESEARCH DESIGN AND METHODS: We have estimated LDL peak particle size by nondenaturing 2-16% gradient gel electrophoresis in a sample of 79 men. Glucose tolerance and fasting plasma insulin and lipoprotein levels were also measured. RESULTS: The LDL particle score, calculated from migration, distances and relative band intensities and reflecting the proportion of small dense LDL particles, was positively correlated with plasma triglyceride (TG) (r = 0.60, P < 0.0001) and negatively correlated with HDL cholesterol (r = -0.56, P < 0.0001) levels. Although the LDL particle score was not associated with variations in plasma LDL cholesterol or LDL apolipoprotein (apo) B concentrations, it was significantly correlated with the LDL apo B-to-LDL cholesterol ratio (r = 0.60, P < 0.0001). Fasting plasma insulin and visceral adipose tissue (AT) areas measured by computed tomography were weakly but significantly correlated with the LDL particle score (r = 0.23 and 0.29, respectively, P < 0.05). LDL peak particle size showed similar but inverse correlations with anthropometric and metabolic variables. Subjects classified as having small dense LDL particles (by comparing subjects in the highest tertile versus those in the lowest tertile of the LDL particle score distribution) were characterized by increased plasma TG, reduced HDL cholesterol, higher fasting insulin levels, and elevated visceral AT accumulation. However, multiple regression analyses revealed that visceral AT accumulation was not an independent predictor of the dense LDL phenotype after inclusion of TG and HDL cholesterol levels and lipoprotein ratios in the model. CONCLUSIONS: It thus appears that the high TG-low HDL cholesterol dyslipidemia frequently found in visceral obesity and in a hyperinsulinemic state is a strong correlate of the small dense LDL phenotype. Although associated with the dense LDL phenotype, visceral obesity and hyperinsulinemia were not independent predictors of an increased proportion of small dense LDL particles after controlling for TG and HDL cholesterol levels.

Effects of dextrothyroxine on the pituitary-thyroid axis in hypercholesterolemic children and goitrous adults.

To evaluate the effects of dextrothyroxine (D-T4) on the pituitary-thyroid axis, we have measured the secretion of TSH in response to TRH in six goitrous adults and six euthyroid children with familial hypercholesterolemia. Since the effects of thyroid hormones appear to be mediated by specific nuclear receptors, the binding affinity of D-T4 was also studied. In both groups of subjects, D-T4 completely abolished the expected TRH stimulation of TSH and T3 secretion. The in vitro binding of D-T4 to rat pituitary nuclear receptors is only 3% that of L-T3, but the binding of D-T3 was similar to that of L-T4 (13% and 11%, respectively). The high circulating levels of D-T4 and possibly of D-T3 after chronic administration of D-T4 may be responsible for the saturation of pituitary nuclear T3 receptors, resulting in the suppression of the TRH-induced TSH response. During the treatment period, total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol were significantly decreased by 18%, 18%, and 19%, respectively. Plasma triglyceride levels and the ratio of total to high density lipoprotein cholesterol were not affected. Although D-T4 lowers cholesterol levels, in view of its suppressive effect on the pituitary-thyroid axis, caution must be exercised with regard to its long term use in children.

A hepatic lipase gene mutation associated with heritable lipolytic deficiency.

Absent hepatic lipase (HL) activity results in dyslipidemia and premature atherosclerosis. DNA sequencing of the HL gene from subjects with heritable HL deficiency identified a new C to T substitution within exon 8 that in the mature enzyme caused a threonine to methionine change at position 383 (T383M). With a rapid DNA detection method we observed that all 6 individuals with complete HL deficiency from 2 families had the T383M mutation. None of 50 random unrelated unaffected subjects had this mutation. We propose that T383M is specific to families with heritable HL deficiency. Furthermore, structural variation at the HL gene, possibly in combination with other factors, appears to be etiologic in HL deficiency.

Changes in plasma lipoproteins during various androgen suppression therapies in men with prostatic carcinoma: effects of orchiectomy, estrogen, and combination treatment with luteinizing hormone-releasing hormone agonist and flutamide.

Cardiovascular complications are a well recognized side-effect of antihormonal therapy in men with prostatic carcinoma. We studied changes in plasma lipoproteins in patients with prostate cancer during treatment with several androgen suppression therapies. Estrogen, orchiectomy, and a combination of LHRH agonist and antiandrogen (flutamide) reduced plasma testosterone concentrations (89-92%) and plasma estradiol decreased by 85%, 44%, and 54%, respectively. Estrogen induced hypertriglyceridemia and elevation of plasma HDL cholesterol, phospholipid, and apolipoprotein A-I and A-II concentrations. Low density lipoprotein (LDL) cholesterol decreased but LDL apolipoprotein B did not. These results suggest that the cardiovascular complications that occur during estrogen administration are not mediated through changes in lipoprotein profile, other than the hypertriglyceridemic effect. Orchiectomy caused hypercholesterolemia and an increase in both total and LDL apolipoprotein B, all of which are strong determinants of cardiovascular disease. The high density lipoprotein (HDL) concentration was not affected despite a reduction in plasma testosterone, perhaps due to a simultaneous decrease in estradiol. Combination therapy had no effect on plasma lipid and apolipoprotein B concentrations, but very low density lipoprotein (VLDL) apolipoprotein B decreased, and LDL apolipoprotein B increased. The HDL cholesterol and apolipoprotein A-I concentrations increased but A-II and phospholipids did not. These results suggest enhanced lipoprotein lipase activity, consistent with the reciprocal changes in VLDL and LDL apolipoprotein B levels, apolipoprotein B enrichment of LDL particles, and increase in HDL cholesterol. The higher apolipoprotein A-I to A-II ratio indicates an increase in HDL2 subfraction due to inhibition of endothelial hepatic lipase, increased secretion of apolipoprotein A-I, or both. These effects are attributed to estradiol, which decreased less than after orchiectomy, and to additional adrenal androgen inhibition by flutamide. We conclude that estradiol plays an important role in determining plasma lipoprotein concentrations in men, and androgens exert an antagonist effect. The lipoprotein profile resulting from the combination treatment is more beneficial than that resulting from orchiectomy or estrogen administration.

Changes in plasma lipoprotein and apolipoprotein composition in relation to oral versus percutaneous administration of estrogen alone or in cyclic association with utrogestan in menopausal women.

Sixty-three postmenopausal women were assigned to four treatment groups and received either Premarin or percutaneous 17 beta-estradiol (Oestrogel) alone or in combination with micronized progesterone (Utrogentan). The oral administration of estrogen alone to hysterectomized women resulted in: 1) a significant increase in triglyceride levels in plasma and all major lipoprotein fractions, 2) a significant increase in very low density lipoprotein cholesterol, 3) a significant decrease in low density lipoprotein (LDL) cholesterol but not LDL apo B concentration, 4) a significant increase in all the lipid components of high density lipoprotein (HDL) as well as apo AI, 5) and a significant increase in HDL2 cholesterol. In contrast, percutaneous administration of estrogen to hysterectomized women only increased HDL2 cholesterol and the triglyceride and cholesterol content of the whole HDL fraction. These results suggest that the route of estrogen administration is important in determining effects on lipoprotein metabolism. The same two estrogens were given to women with natural menopause, along with utrogestan, a micronized progesterone. The simultaneous administration of Utrogestan reversed the HDL cholesterol elevating effect of percutaneous estrogen alone, but it had no effect on other plasma lipoproteins. On the other hand, utrogestan in combination with oral estrogen had several potential beneficial effects on plasma lipoproteins. This combination did not negate the effects of oral estrogen alone on HDL, rather it further increased the concentrations of HDL cholesterol and apo AI. It also did not negate the LDL cholesterol lowering effect of oral estrogen alone. Furthermore, utrogestan lowered the magnitude of hypertriglyceridemia induced by oral estrogen alone. These results suggest that Utrogestan has lower potency of androgenic action and has desirable effects when given in cyclic combination with estrogen.

Abdominal fat cell lipolysis, body fat distribution, and metabolic variables in premenopausal women.

It is well established that abdominal obesity is related to numerous metabolic abnormalities and that this correlation represents a significant risk factor for coronary heart disease and related mortality. In the present study the relationships among the regional distribution of body fat, selected metabolic variables, and abdominal adipose cell lipolysis were investigated in 30 premenopausal women, 34 +/- 8 yr (mean +/- SD) of age, with body mass indices ranging from 17-45 kg/m2. Basal as well as epinephrine- and isoproterenol-stimulated lipolyses were positively correlated with fasting plasma insulin and triglyceride levels (0.48 less than r less than 0.64; 0.05 greater than P less than 0.0005 and 0.46 less than r less than 0.60; 0.05 greater than P less than 0.005, respectively) and with the insulin area measured during an oral glucose tolerance test (0.49 less than r less than 0.67; 0.005 greater than P less than 0.0005). With the exception of epinephrine-stimulated lipolysis, these correlations remained significant when lipolysis was corrected for cell surface area. Basal and maximal epinephrine- and isoproterenol-induced lipolyses were also negatively related to plasma high density lipoprotein cholesterol (-0.52 less than r less than -0.36; 0.05 greater than P less than 0.005). However, these relationships were no longer significant after control for fat cell surface. The associations between abdominal lipolysis and fat distribution did not remain significant when data were adjusted for total adiposity. Taken together, these results support the notion that variations in abdominal adipocyte lipolysis 1) depend more on total body fatness than on fat distribution, and 2) may be involved in the metabolic complications associated with abdominal obesity, particularly those pertaining to plasma insulin and triglyceride metabolism.

Dose-response to tibric acid: a new hypolipidemic drug in type IV hyperlipoproteinemia.

This double-blind study compares the effects of tibric acid at four different doses to that of placebo in type IV hyperlipidemic patients. Fifty patients, divided at random in five groups of 10 patients each, received one of the following treatments: placebo, tibric acid 500 mg, 750 mg, 1,000 mg, or 1,250 mg per 24 hr. The data suggest that the 1,000 mg and the 1,250 mg doses are effective in lowering the serum triglyceride levels after 6 wk of treatment; the effect on total cholesterol is less pronouced. No effect is observed on the concentration of serum esterified cholesterol, phospholipids, and free fatty acids. It is also shown that in the dose range studied, the best fitting curve defining the four mean values of triglycerides and total cholesterol obtained with the four active treatments did not deviate significantly from linearity. Due to lack of toxicity, tibric acid may be useful in the treatment of type IV hyperlipoproteinemia.

Effects on plasma lipoproteins and endogenous sex hormones of substituting lean white fish for other animal-protein sources in diets of postmenopausal women.

A crossover 8-wk study was conducted to compare the effects on plasma lipoproteins and endogenous sex hormones of lean white fish (LWF) and of beef, pork, egg, and milk (BPEM) within a prudent diet in postmenopausal women. Diets provided 8050 kJ as 19% proteins, 52% carbohydrates, 29% lipids (P/M/S (proportion of polyunsaturated, monounsaturated, and saturated fatty acids, 1.1:1:1) and approximately 210 mg cholesterol/d. The LWF diet compared with the BPEM diet significantly induced higher concentrations of plasma cholesterol, LDL-apo B, HDL-C, and HDL3-C, indicating that incorporation of LWF as a substitute for BPEM in a low-fat, high-P:S diet offers little benefit with regard to plasma cholesterol and LDL-apoB in postmenopausal women. Moreover, the LWF diet significantly increased plasma SHBG, suggesting that the divergent effects of substituting LWF for other animal-protein sources on plasma cholesterol and lipoproteins may be partly mediated by variations in plasma sex-hormone status.

Effects of a soy-protein beverage on plasma lipoproteins in children with familial hypercholesterolemia.

The effects of soy protein (35% of protein energy) given as a beverage and those of cow-milk proteins were investigated on plasma lipoprotein concentrations in children with familial hypercholesterolemia (FH). Subjects were randomly assigned to either the soy-protein or cow-milk-protein experimental period, with subsequent crossover after a washout period, each period lasting 4 wk. Diets were planned to provide 20% energy as protein, 28% as fat (polyunsaturated:monounsaturated:saturated fatty acids, 1:3:3) and less than 200 mg cholesterol/d. No changes were observed in either plasma cholesterol, low-density-lipoprotein cholesterol, or apolipoprotein concentrations. However, the soy beverage significantly reduced the concentrations of triglyceride and very-low-density-lipoprotein cholesterol (P less than 0.05) and significantly increased the concentrations of high-density-lipoprotein cholesterol (HDL-C) and HDL3-C (P less than 0.04 and P less than 0.03, respectively). These results indicate that the administration of soy protein may induce clinically beneficial effects in children with FH.

Plasma lipoprotein profile and lipolytic activities in response to the substitution of lean white fish for other animal protein sources in premenopausal women.

A crossover study was conducted to examine the effects on plasma lipoprotein concentrations of substituting lean white fish (LWF) for beef, port, veal, eggs, and milk products (BPVEM) within prudent isoenergetic diets. Fourteen premenopausal women received 8784 kJ--20% as protein, 50% as carbohydrates, and 30% as lipids [ratio of polyunsaturated to monounsaturated to saturated fatty acids (P:M:S) of 1:1:1 compared with 0.4:1:1 in preexperimental diet]--and 260 mg cholesterol/d. After 4 wk, the BPVEM diet significantly reduced concentrations of plasma cholesterol, low-density-lipoprotein (LDL) cholesterol, high-density-lipoprotein (HDL) cholesterol, apolipoprotein B, HDL-apolipoprotein A-I, and LDL-apolipoprotein B (P<0.05) as well as plasma postheparin hepatic triacylglycerol lipase activity compared with the preexperimental diet. These effects are probably attributable to elevation of the P:M:S. These responses were not observed with the LWF diet, suggesting that fish protein in LWF maintains unchanged plasma cholesterol concentrations despite a high P:M:S. The LWF diet, compared with the preexperimental diet, reduced very-low-density-lipoprotein triacylglycerol (P<0.05) and also the ratio of LDL cholesterol to apolipoprotein B (P<0.05), revealing the presence of denser LDL particles. Compared with the BPVEM diet, the LWF diet induced lower concentrations of very-low-density-lipoprotein triacylglycerols (P<0.05) and higher concentrations of LDL triacylglycerol and LDL apolipoprotein B (P<0.05), which were not associated with any increase in lipoprotein lipase activity. These results suggest that LWF as a substitute for BPVEM in isoenergetic diets with an elevated P:S produces minimal improvement in the lipoprotein profile in premenopausal women.

Triglycerides and HDL-cholesterol as risk factors for ischemic heart disease. Results from the Québec cardiovascular study.

The relative importance of reduced plasma high density lipoprotein-cholesterol (HDL-C) levels and elevated plasma triglyceride (TG) concentrations as risk factors for ischemic heart disease (IHD) was examined in a sample of 2177 men from the Québec City suburbs. The sample included 202 men with known IHD. The relationship between HDL-C and TG levels, although significant (r = -0.49, P < 0.0001), was not linear, as most of the variation in HDL-C levels was observed within TG levels below 2.5 mmol/l. Reduced HDL-C (< 0.9 mmol/l) was a prevalent condition in men with IHD (50%) compared to those without IHD (30%). On the other hand 26% and 20% of men with and without IHD, respectively, had elevated TG levels (TG > 2.3 mmol/l). A 2-fold increase in prevalence odds ratio (OR) was observed in men with TG levels > 2.3 mmol/l (95% confidence intervals (CI) [1.2;3.3]). No residual association between elevated TG levels and IHD was found, however, after adjustment for HDL-C concentrations (OR 1.2, 95% CI 0.7;2.1). On the other hand, HDL-C remained a significant predictor of IHD after adjustment for other risk factors (OR 0.3, 95%, CI 0.2;0.6). Men with reduced HDL-C levels were also characterized by a cluster of risk factors such as obesity, diabetes mellitus and hypertension, which may contribute to increase the risk of IHD. Finally, the independent interpretation of cholesterol, TG or LDL-C levels may lead to an inadequate prediction of risk, as a large number of IHD patients showed a cluster of risk factors which included low HDL-C concentrations.

The MspI polymorphism of the apolipoprotein A-II gene as a modulator of the dyslipidemic state found in visceral obesity.

The aim of the present study was to examine the effect of variation at the apolipoprotein (apo) A-II gene locus on lipoprotein levels in visceral obesity. A total of 145 sedentary men, free from metabolic disorders requiring pharmacotherapy, were classified into two groups on the basis of their apo A-II-MspI genotype determined by the polymerase chain reaction: 1) 43 M1 carriers or M1M2, including two M1M1 homozygotes and 41 M1M2 heterozygotes, and 2) 102 M2M2 homozygotes for the presence of a MspI restriction site. The two genotypic groups did not differ for body mass index (BMI, expressed in kg/m2), body fat mass, visceral adipose tissue (AT) accumulation, as well as for insulin, glucose and free fatty acids levels measured in the fasting state and in response to an oral glucose tolerance test. In addition, 65 and 63% of M1 carriers had plasma HDL2 cholesterol levels and a HDL2/HDL3 cholesterol ratio below the 50th percentile of their distributions compared with 45%(P < 0.05) and 46%(P = 0.06), respectively, in M2M2 homozygotes. When subjects were further divided on the basis of visceral AT accumulation (below and above a value of 130 cm2), M1 carriers with low levels of visceral AT were characterized by high plasma HDL cholesterol and HDL2 cholesterol concentrations as well as by a higher HDL2/HDL3 ratio, compared with M1 carriers with high levels of visceral AT (> 130 cm2), or with M2M2 homozygotes with either a high or a low accumulation of visceral AT. Furthermore, M1 carriers with high levels of visceral AT showed a trend for lower plasma HDL2 cholesterol levels and were characterized by a significantly lower HDL2/HDL3 cholesterol ratio compared with the other three groups. No difference in HDL and HDL2 cholesterol levels and in the HDL2/HDL3 cholesterol ratio was noted when M2 homozygotes with lower versus higher levels of visceral AT were compared. The contribution of hyperinsulinemia was also examined by dividing subjects on the basis of the 50th percentile of the integrated insulin response to an oral glucose challenge. Significantly lower plasma HDL2 cholesterol levels and a reduced HDL2/HDL3 cholesterol ratio were noted among M1 carriers with high plasma insulin responses compared with M1 carriers with low insulin responses. Among M2M2 homozygotes, no difference was noted in plasma HDL cholesterol and in HDL2 cholesterol concentrations between men with low versus high insulin responses to the oral glucose load. These results suggest that the apo A-II-MspI polymorphism could modulate plasma HDL cholesterol levels among visceral obese, insulin-resistant men.

Do elevated levels of abdominal visceral adipose tissue contribute to age-related differences in plasma lipoprotein concentrations in men?

Age-related differences in body fat and more specifically in the accumulation of abdominal visceral adipose tissue were examined as a potential covariate for the alteration in the plasma lipoprotein profile found with aging. For that purpose, results from 79 young adults (aged 24.5 +/- 4.0 years) were compared to 61 middle-aged men (54.7 +/- 6.4 years). Younger men had significantly lower body fat mass and abdominal visceral adipose tissue area measured by computed tomography than middle-aged men (P < 0.0001). Plasma cholesterol, triglyceride, apolipoprotein (apo) B, low density lipoprotein (LDL)-cholesterol and LDL apo B levels, as well as the ratio of plasma cholesterol to high density lipoprotein (HDL)-cholesterol were all significantly lower in younger men as compared to middle-aged men (P < 0.0001). The comparison of younger men to middle-aged men with comparable levels of abdominal visceral fat and total body fat eliminated the age-related differences in plasma triglyceride and in the ratio of plasma cholesterol to HDL-cholesterol, whereas the difference in plasma apolipoprotein B levels, although still significant, was largely reduced. Age-related differences in plasma cholesterol and in LDL-cholesterol levels were still observed after this matching procedure and the differences between age-groups were essentially of similar magnitude than before pairing. In summary, these results suggest that the deterioration of plasma lipoprotein profile observed in middle-aged men as compared to young adult men is partly mediated by concomitant increases in total body fat and abdominal visceral adipose tissue. However, other factors related to the aging process appear to be involved, particularly for the age-related increase in plasma LDL-cholesterol.