Low-density lipoprotein particle size is inversely related to plasminogen activator inhibitor-1 levels. The Insulin Resistance Atherosclerosis Study

The effect of single clove Black garlic on the hemostasis status and lipid profile in male Sprague Dawley rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) patients have alteration in hemostasis components. Thus, including excess expression of plasminogen activator inhibitor-1 (PAI-1), causing fibrinolysis disorders; the majority of these patients are hypercoagulable state prone to thrombosis. Some evidence suggests that garlic and garlic supplements have antithrombotic and anti-inflammatory properties. Besides, garlic stimulates fibrinolytic activity and normalizes plasma lipid imbalances. Black garlic is processed garlic that is produced through natural aging at a controlled temperature (70 °C) and high humidity (90%) for several days, without other additives. This study aimed to prove the effect of single clove black garlic (SCBG) (Allium sativum Linn) on PAI-1 levels and lipid profiles of NAFLD rats induced by a high-fat fructose diet (HFFD) containing 1.25% cholesterol and 0.5% cholic acid.The rats were then divided into healthy control group (K1+); NAFLD control group without treatment (K2+); 0.9 mg simvastatin treatment group (K1-); 45 mg metformin treatment group (K2-); SCBG 450 mg per 200g BW (X1); 900 mg per 200 g BW (X2); and 1350 mg per 200 g BW (X3). All treatments were administered for 4 weeks via oral gavage. As a result, significant differences in PAI-1 levels and lipid profiles between groups after the administration (p = 0.001) were noted and also by simvastatin and metformin, respectively. There was a correlation between PAI-1 and lipid profile of SCBG treatment. In conclusion, the administration of SCBG (1350 mg per 200 g BB per day) for 4 weeks had a significant effect on PAI-1 levels, and the lipid profiles in Sprague Dawley rats modeled NAFLD (p = 0.001). SCBG has provided benefits that can be useful in the management of NAFLD but it’s not equivalent to medicine.

Association of plasminogen activator inhibitor-1 and low-density lipoprotein heterogeneity as a risk factor of atherosclerotic cardiovascular disease with triglyceride metabolic disorder: a pilot cross-sectional study

BACKGROUND

We hypothesized that an increase in plasminogen activator inhibitor 1 (PAI-1) might reduce low-density lipoprotein (LDL) particle size in conjunction with triglyceride (TG) metabolism disorder, resulting in an increased risk of atherosclerotic cardiovascular disease (ASCVD).

METHODS

This study was carried out as a hospital-based cross-sectional study in 537 consecutive outpatients (mean age: 64 years; men: 71%) with one or more risk factors for ASCVD from April 2014 to October 2014 at the Cardiovascular Center of Nihon University Surugadai Hospital. The estimated LDL-particle size was measured as relative LDL migration using polyacrylamide gel electrophoresis with the LipoPhor system.The plasma PAI-1 level, including the tissue PA/PAI-1 complex and the active and latent forms of PAI-1, was determined using a latex photometric immunoassay method.

RESULTS

A multivariate regression analysis after adjustments for ASCVD risk factors showed that an elevated PAI-1 level was an independent predictor of smaller-sized LDL-particle in both the overall patients population (β=0.209, P<0.0001) and a subset of patients with a serum low-density lipoprotein cholesterol (LDL-C) level lower than 100 mg/dl (β=0.276, P<0.0001). Furthermore, an increased BMI and TG-rich lipoprotein related markers [TG, remnant-like particle cholesterol, apolipoprotein (apo) B, apo C-II, and apo C-III] were found to be independent variables associated with an increased PAI-1 level in multivariate regression models. A statistical analysis of data from nondiabetic patients with well-controlled serum LDL-C levels yielded similar findings. Furthermore, in the 310 patients followed up for at least 6 months, a multiple-logistic regression analysis after adjustments for ASCVD risk factors identified the percent changes of the plasma PAI-1 level in the third tertile compared with those in the first tertile as being independently predictive of decreased LDL-particle size [odds ratio (95% confidence interval): 2.11 (1.12/3.40), P=0.02].

CONCLUSION

The plasma PAI-1 levels may be determined by the degree of obesity and TG metabolic disorders. These factors were also shown to be correlated with a decreased LDL-particle size, increasing the risk of ASCVD, even in nondiabetic patients with well-controlled serum LDL-C levels.

Plasminogen Activator Inhibitor-1 Level Correlates with Lipoprotein Subfractions in Obese Nondiabetic Subjects

BACKGROUND

The elevated level of plasminogen activator inhibitor-1 (PAI-1) in obese subjects with metabolic syndrome and in patients with type 2 diabetes is well established. The association of plasma PAI-1 and lipid metabolism is still unclear. The aim of the present study was to determine the relationship between plasma PAI-1 levels and the distribution of lipoprotein subfractions in obese and lean nondiabetic individuals.

SUBJECTS AND METHODS

We enrolled fifty nondiabetic obese patients and thirty-two healthy volunteers. Lipoprotein subfractions were detected with Lipoprint System. Plasma PAI-1, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) concentrations were determined with enzyme-linked immunosorbent assay (ELISA), while serum paraoxonase-1 (PON1) activities were measured by spectrophotometry.

RESULTS

The TNF-α, IL-6, oxidized low-density lipoprotein (oxLDL), and MPO levels were found to be significantly higher, while PON1 paraoxonase and arylesterase activities were nonsignificantly lower in the obese patients. Strong significant negative correlations were found between plasma PAI-1 concentration and mean LDL size, as well as between PAI-1 concentrations and the levels of the large and intermediate high-density lipoprotein (HDL) subfractions. In multiple regression analysis, PAI-1 was predicted by waist circumference and intermediate HDL subfraction.

CONCLUSION

The significant correlations between PAI-1 levels and lipoprotein subfractions indicate the link between PAI-1 and lipid metabolism in obesity.

Apolipoprotein B vs non-high-density lipoprotein cholesterol: Association with endothelial hemostatic markers and carotid intima-media thickness

BACKGROUND

Both apolipoprotein B (apoB) and non-high-density lipoprotein cholesterol (non-HDL-C) are accepted as alternative risk factors or targets for lipid-lowering therapy, which correlate more strongly with cardiovascular events than low-density lipoprotein cholesterol.

OBJECTIVE

The aim of this cross-sectional study was to evaluate the differences in plasma levels of plasminogen activator inhibitor-1 (PAI-1) and of von Willebrand factor (vWF) as endothelial hemostatic markers and carotid intima-media thickness (C-IMT) as a morphologic marker for atherosclerotic vascular disease among dyslipidemic individuals with apoB levels higher, estimated or lower based on regression equation of apoB vs non-HDL-C.

METHODS

A total of 594 dyslipidemic subjects without atherosclerotic manifestation were divided into 3 groups (according to tertiles of apoB levels above, within, and below the line of identity): H-apoB (n = 200), E-apoB (n = 194), and L-apoB (n = 200). PAI-1, vWF, C-IMT and lipids, anthropometric parameters, markers of insulin resistance, and inflammation were measured. Differences in variables between groups were analyzed using analysis of variance.

RESULTS

There was a strong association between apoB and non-HDL-C. The correlations of apoB and of non-HDL-C with markers of endothelial damage and C-IMT were very similar. Despite these facts, individuals with higher apoB levels had significantly higher levels of PAI-1 compared with individuals with estimated (P < .05) or lower apoB (P < .001). There were no significant differences in vWF, C-IMT, markers of insulin resistance, obesity, and inflammation.

CONCLUSION

Individuals with apoB higher than predicted by non-HDL-C had significantly higher levels of PAI-1, which may contribute to the increased risk of future atherothrombotic events.

The effects of treatment on lipoprotein subfractions evaluated by polyacrylamide gel electrophoresis in patients with autoimmune hypothyroidism and hyperthyroidism

BACKGROUND

Atherogenic dyslipoproteinemia is one of the most important risk factor for atherosclerotic changes development. Hypothyroidism is one of the most common causes of secondary dyslipidemias which results from reduced LDL clearance and therefore raised levels of LDL and apoB. Association between small dense LDL (sdLDL) presentation and thyroid status has been examinated using polyacrylamide gel electrophoresis for lipoprotein subfractions evaluation.

METHODS

40 patients with diagnosed autoimmune hypothyroidism and 30 patients with autoimmune hyperthyroidism were treated with thyroxine replacement or thyreo-suppressive treatment. In both groups lipid profiles, LDL subractions, apolipoproteins (apoA1, apoB), apoA1/apoB ratio and atherogenic index of plazma (AIP) were examined before treatment and in state of euthyreosis.

RESULTS

Thyroxine replacement therapy significantly reduced levels of total cholesterol (TC), LDL, triglycerides (TG) and also decreased levels of sdLDL (8,55±11,671 vs 0,83±1,693mg/dl; p<0,001), apoB and AIP. For estimation of atherogenic lipoprotein profile existence an AIP evaluation seems to be better than apoB measurement because of the more evident relationship with sdLDL (r=0,538; p<0,01). Thyreo-suppressive therapy significantly increased levels of TC, LDL, TG and apoB. The sdLDL was not found in hyperthyroid patients.

CONCLUSIONS

Atherogenic lipoprotein profile was present in 52.5% of hypothyroid subjects, which is higher prevalence than in normal, age-related population. Substitution treatment leads to an improvement of the lipid levels, TG, apoB, AIP and LDL subclasses. It significantly changed the presentation of sdLDL - we noticed shift to large, less atherogenic LDL particles. Significantly positive correlation between sdLDL and TAG; sdLDL and VLDL alerts to hypertriglyceridemia as a major cardiovascular risk factor.

Racial/ethnic differences in dyslipidemia patterns

BACKGROUND

No studies have comprehensively examined the prevalence of dyslipidemia, a major risk factor for cardiovascular disease, among diverse racial/ethnic minority groups. The primary aim of this study was to identify racial/ethnic differences in dyslipidemia among minorities including Asian Americans (Asian Indian, Chinese, Filipino, Japanese, Korean, or Vietnamese), Mexican Americans, and blacks compared with non-Hispanic whites.

METHODS AND RESULTS

Using a 3-year cross section (2008-2011), we identified 169 430 active primary care patients (35 years or older) from an outpatient healthcare organization in northern California. Age-standardized prevalence rates were calculated for 3 dyslipidemia subtypes: high triglycerides (fasting laboratory value ≥150 mg/dL), low levels of high-density lipoprotein cholesterol (fasting laboratory value <40 mg/dL [men] and <50 mg/dL [women]), and high levels of low-density lipoprotein cholesterol (fasting laboratory value ≥130 mg/dL or taking low-density lipoprotein-lowering agents). Odds ratios were calculated by multivariable logistic regression, with adjustment for patient characteristics (age, measured body mass index, smoking). Compared with non-Hispanic whites, every minority subgroup had an increased prevalence of high triglycerides except blacks. Most minority groups had an increased prevalence of low high-density lipoprotein cholesterol, except for Japanese and blacks. The prevalence of high low-density lipoprotein cholesterol was increased among Asian Indians, Filipinos, Japanese, and Vietnamese compared with non-Hispanic whites.

CONCLUSIONS

Minority groups, except for blacks, were more likely to have high triglyceride/low high-density lipoprotein cholesterol dyslipidemia. Further research is needed to determine how racial/ethnic differences in dyslipidemia affect racial/ethnic differences in cardiovascular disease rates.

Smaller Mean LDL Particle Size and Higher Proportion of Small Dense LDL in Korean Type 2 Diabetic Patients

BACKGROUND

Small dense low density lipoprotein (sdLDL) has recently emerged as an important risk factor of coronary heart disease.

METHODS

The mean LDL particle size was measured in 203 patients with type 2 diabetes mellitus (T2DM) and 212 matched subjects without diabetes using polyacrylamide tube gel electrophoresis. Major vascular complications were defined as stroke, angiographically-documented coronary artery disease or a myocardial infarction. Peripheral vascular stenosis, carotid artery stenosis (≥50% in diameter) or carotid artery plaque were considered minor vascular complications. Overall vascular complications included both major and minor vascular complications.

RESULTS

Diabetic patients had significantly smaller mean-LDL particle size (26.32 nm vs. 26.49 nm) and a higher percentage of sdLDL to total LDL compared to those of subjects without diabetes (21.39% vs. 6.34%). The independent predictors of sdLDL in this study were serum triglyceride level and body mass index (odds ratio [OR], 1.020 with P<0.001 and OR 1.152 with P<0.027, respectively). However, no significant correlations were found between sdLDL and major vascular complications (P=0.342), minor vascular complications (P=0.573) or overall vascular complications (P=0.262) in diabetic subjects.

CONCLUSION

Diabetic patients had a smaller mean-LDL particle size and higher proportion of sdLDL compared to those of subjects without diabetes. Obese diabetic patients with hypertriglyceridemia have an increased risk for atherogenic small dense LDL. However, we could not verify an association between LDL particle size and vascular complications in this study.

Plasminogen activator inhibitor-1 (PAI-1): a key factor linking fibrinolysis and age-related subclinical and clinical conditions

INTRODUCTION

The close relationship existing between aging and thrombosis has growingly been studied in this last decade. The age-related development of a prothrombotic imbalance in the fibrinolysis homeostasis has been hypothesized as the basis of this increased cardiovascular and cerebrovascular risk. Fibrinolysis is the result of the interactions among multiple plasminogen activators and inhibitors constituting the enzymatic cascade, and ultimately leading to the degradation of fibrin. The plasminogen activator system plays a key role in a wide range of physiological and pathological processes.

METHODS

Narrative review.

RESULTS

Plasminogen activator inhibitor-1 (PAI-1) is a member of the superfamily of serine-protease inhibitors (or serpins), and the principal inhibitor of both the tissue-type and the urokinase-type plasminogen activator, the two plasminogen activators able to activate plasminogen. Current evidence describing the central role played by PAI-1 in a number of age-related subclinical (i.e., inflammation, atherosclerosis, insulin resistance) and clinical (i.e., obesity, comorbidities, Werner syndrome) conditions is presented.

CONCLUSIONS

Despite some controversial and unclear issues, PAI-1 represents an extremely promising marker that may become a biological parameter to be progressively considered in the prognostic evaluation, in the disease monitoring, and as treatment target of age-related conditions in the future.

PAI-1 activity, but not fibrinogen or von Willebrand factor, is inversely related to LDL particle size in type 2 diabetes

BACKGROUND

Levels of fibrinogen, von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1) have been associated with small low-density lipoprotein (LDL) particles. However, it is not clear whether these associations are independent of visceral adiposity or other components of the metabolic syndrome such as triglycerides or insulin resistance.

METHODS

Visceral adipose tissue (VAT; CT-scan), fibrinogen, von Willebrand factor antigen (vWF:Ag), PAI-1 activity and different metabolic parameters such as total cholesterol (chol), HDL-chol, triglycerides, insulin resistance (homeostasis model assessment; HOMA-IR) were determined in 41 women and 78 men with type 2 diabetes. LDL particle size was assessed by polyacrylamide gradient gel electrophoresis.

RESULTS

PAI-1 activity was inversely related to LDL particle size after adjustment for age and body mass index (BMI) (r=-0.28; p=0.006) or age and VAT (r=-0.26; p=0.01), but not after adjustment for age and HOMA-IR (r=-0.15; p=0.148) or age and triglycerides (r=-0.04; p=0.679). In multiple regression analysis, LDL particle size did not independently determine PAI-1 activity levels. Fibrinogen and vWF:Ag did not seem to be related to LDL size.

CONCLUSIONS

PAI-1 activity levels, in contrast to fibrinogen and vWF:Ag, seem to be related to the small LDL phenotype in patients with type 2 diabetes. However, this relationship was not independent of insulin resistance or triglycerides.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Significance of small dense low-density lipoprotein as a risk factor for coronary artery disease and acute coronary syndrome

Small dense LDL (sd-LDL) has recently emerged as an important coronary artery disease (CAD) risk factor. This study was performed to investigate how LDL particle size is related to CAD and acute coronary syndrome (ACS). Blood samples were collected from 504 patients that underwent coronary angiography to evaluate chest pain. The LDL particle size of these samples was measured. The mean LDL particle size was smaller in patients with angiographically proven CAD than in the controls (26.41 +/- 0.95 vs 26.73 +/- 0.64 nm, p < 0.001), and was negatively correlated with the Framingham risk score (r=-0.121, p=0.007). Patients with more extensive CAD had smaller LDL particles. LDL particle size was also smaller in patients with acute coronary syndrome as compared to non-ACS patients (26.09 +/- 1.42 vs 26.54 +/- 0.63 nm, p=0.011). These results suggest that sd-LDL is independently associated with the incidence and extent of CAD, and can be a risk factor for the development of ACS in the Korean population.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Chronische Therapie des metabolischen Syndroms bei herzoperierten Diabetikern

Patients with type 2 diabetes often also exhibit additional features of the metabolic syndrome. These include specifically central obesity triggering development and maintenance of diabetes together with arterial hypertension, hypertriglyceridemia and low levels of high-density lipoprotein cholesterol. Chronic therapy of the metabolic syndrome in diabetics after coronary bypass surgery focuses on changes in lifestyle, i.e., cessation of smoking, changes in nutrition and increase in physical activity. Nutrition aims at fat reduction and modification to reduce saturated fatty acids, to allow mono- and polyunsaturated fatty acids instead, and moderate alcohol consumption. High fiber and complex carbohydrate diet complete the recommendations. Nutrition therapy connected to increases in physical activity are aimed at reducing weight in overweight and obese subjects, which should reduce their body weight by 5 to 10% within about 6 months. Normal weight subjects benefit from increases in physical activity by lipid and glucose regulation as well as by reduction in mortality.Diabetes-specific therapy aims at normoglycemia including postprandial blood glucose levels, reduces blood pressure supported by ACE inhibitors and aims at weight reduction. Reduction of LDL-cholesterol is the first line therapy, also diminishing small-dense LDL particles. Decreasing triglycerides and increasing HDL-cholesterol are further lipid-regulating aims. Specifically diabetics after coronary bypass surgery need LDL-cholesterol levels below 70 mg/d (1.8 mmol/L) and triglycerides below 150 mg/dL (1.7 mmol/L). In addition, in males HDL-cholesterol should be at least above 40 mg/dl (1 mmol/L), in females above 50 mg/dL (1.3 mmol/L).

Sesamol regulates plasminogen activator gene expression in cultured endothelial cells: a potential effect on the fibrinolytic system

Sesamol is a component in the nutritional makeup of sesame that was identified as an antioxidant. In recent years, the importance of the plasminogen activator (PA) and its adjustment factor, plasminogen activator inhibitor-1 (PAI-1), in the prevention of atherosclerosis has gradually received recognition. The objective of this in vitro study was to demonstrate the effects of sesamol on PA and PAI-1. We also compared the effects of sesamol with two well-known antioxidants, vitamins C and E, by using human umbilical vein endothelial cells as an experimental model and by treating them with the above-mentioned three nutrients with doses up to 100 micromol/L. After 24 h, cells and cultural medium were collected for analysis. The concentrations of tissue PA (tPA), urokinase PA (uPA) and PAI-1 were measured by an enzymatic immunity method. Northern blot method was used to analyze the expression of mRNA of these three types of proteins. The results showed that sesamol increased the production of uPA and tPA significantly and also up-regulated the mRNA expressions of these proteins. On the other hand, vitamins C and E could induce tPA but not uPA. As for PAI-1, none of the nutrients induced any evident response. These findings suggest that the overall vascular fibrinolytic capacity may be enhanced by using sesamol to regulate PA gene expression.

Insulin resistance and cardiovascular disease: the role of PPARgamma activators beyond their anti-diabetic action

Over the past few years it has been recognised that insulin resistance (IR) is an independent risk factor for major cardiovascular events. In addition, IR is associated with other factors such as hypertension, dyslipidaemia and endothelial dysfunction, and this cluster of metabolic disorders contributes to the cardiovascular risk of patients with IR. Given the increasing number of patients with IR, the modulation of their cardiovascular risk is a major task in diabetology and vascular medicine. This review will focus on the role of IR as a cardiovascular risk factor and on the potential of activators of the nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) to modulate these risk factors associated with IR.

Metabolic syndrome: an appraisal of the pro-inflammatory and procoagulant status

Inflammation and hypercoagulability predispose to atherothrombosis and seem to be important features of the metabolic syndrome. The most convincing evidence is the association with increased levels of C-reactive protein. The hemostatic abnormality that has been most consistently associated with insulin resistance is an elevated plasminogen activator inhibitor-1 level. In contrast, markers of hypercoagulability have been associated inconsistently with hyperinsulinemia and glucose intolerance. Fibrinogen clusters with inflammatory factors, which suggests involvement of adipose tissue-generated inflammatory cytokines. Elevated von Willebrand's factor and factor VIII levels aggregate with indicators of endothelial injury,whereas vitamin K-dependent coagulation proteins correlate with triglyceride levels.

Hypofibrinolysis in the insulin resistance syndrome: implication in cardiovascular diseases

Insulin resistance syndrome (IRS) is associated with increased cardiovascular morbidity and mortality. IRS is becoming one of the major health problems as its prevalence grows rapidly. Accelerated atherothrombotic process in the IRS is attributed to metabolic abnormalities, inflammation and to impaired fibrinolysis due to increased plasma plasminogen activator inhibitor type 1 (PAI-1) levels. Proinflammatory cytokines may have an important role in PAI-1 overexpression, particularly in the adipose tissue. Studies in genetically modified mice indicate that PAI-1 might be involved in the aetiopathogenesis of obesity. Modifying PAI-1 expression by PAI-1 inhibitors may open a new field of research and may reveal the true role of PAI-1 in atherosclerotic and insulin resistance processes.

Physical activity modulates effects of some genetic polymorphisms affecting cardiovascular risk in men aged over 40 years

BACKGROUND AND AIM

Several genetic polymorphisms have been found to be involved in cardiovascular risk, and many studies have documented the beneficial effect of systematic physical activity (PA) on the cardiovascular system. Our aim was to investigate the interactive effects of PA and genetic background on plasma lipids and homocysteine (tHcy) levels.

METHODS AND RESULTS

Clinical and metabolic parameters, dietary intakes and some polymorphisms of the genes involved in cardiovascular risk (Apo E, fatty acid binding protein-2, Apo AII, hepatic lipase and methylene tetrahydrofolate reductase) were determined in 100 men aged over 40 years who cycle 120-150 Km/week and 100 age-matched sedentary controls. The physically active subjects had lower concentrations of plasma LDL cholesterol (LDL-C), triglyceride (TG), Apo B, glucose and tHcy, and higher concentrations of plasma HDL cholesterol (HDL-C) and Apo AI than the sedentary men; they also had larger LDL particle sizes (LDLs). The LDL-C and Apo B raising effect of the Apo E epsilon 4 allele detectable in the sedentary subjects was totally absent in the cyclists, in whom the LDL-C and Apo B lowering effect of the epsilon 2 allele was observed. PA blunted the TG-raising effect of the Apo AII-265TT genotype, and amplified the HDL-C raising effect of the HL-250AA genotype. PA had a small but significant lowering effect on plasma tHcy adjusted for folate levels in subjects with the 677TT genotype of the MTHFR gene.

CONCLUSIONS

Extended high-intensity PA in men aged over 40 years may modify their metabolic cardiovascular risk factors even in the presence of some unfavourable genotypes.

Plasminogen activator inhibitor-1, inflammation, obesity, insulin resistance and vascular risk

Elevated plasma plasminogen activator inhibitor-1 (PAI-1) level is a core feature of insulin-resistance syndrome (IRS). Atherothrombotic complications in IRS are partly attributed to impaired fibrinolysis caused by increased plasma PAI-1 levels. Although the etiology of IRS is far from being explained, the clustering of inflammation, adipose tissue accumulation and insulin resistance suggests an etiopathological link. Proinflammatory cytokines might regulate PAI-1 expression in IRS; however, more studies are needed to confirm this complex mechanism in humans. Furthermore, modifying PAI-1 expression by PAI-1 inhibitors provides a new challenge and may reveal the true role of PAI-1 in atherosclerotic and insulin resistance processes.

Plasma lipids and lipoproteins in hypercholesterolemic men fed a lipid-lowering diet containing lean beef, lean fish, or poultry

BACKGROUND

To reach desirable lipid and lipoprotein concentrations, patients with hypercholesterolemia are often told to replace the consumption of beef with that of fish and poultry.

OBJECTIVE

The objective of this study was to compare the effects on lipoprotein profiles in hypercholesterolemic men of the incorporation of lean beef, poultry (without skin), and lean fish into an American Heart Association diet with a high polyunsaturated-to-saturated fatty acid ratio and a high fiber content.

DESIGN

Three groups of subjects each rotated in a crossover design through 3 experimental periods that lasted 26 d each. The diets were planned to provide 11 713 kJ/d, of which 18% came from protein, 53% from carbohydrate, and 30% from lipids (polyunsaturated-to-monounsaturated-to-saturated fatty acid ratio: 1.0:1.1:1.0); 268 mg cholesterol/d; and 29 g fiber/d.

RESULTS

The lean beef, lean fish, and poultry diets reduced plasma total and LDL cholesterol by 5-9%, LDL apolipoprotein B by 16-19%, VLDL triacylglycerols by 22-31%, and the ratio of total cholesterol to HDL cholesterol by 6-11%; they also increased the ratio of LDL cholesterol to apolipoprotein B by 18-28%. No significant difference was found in these lipid variables between the 3 experimental diets. However, the lean fish diet increased HDL(2) cholesterol significantly more (P < 0.05) than did the lean beef diet and the ratio of HDL(2) to HDL(3) cholesterol significantly more (P < 0.05) than did the lean beef and poultry diets.

CONCLUSION

The results indicate that an American Heart Association diet with a high polyunsaturated-to-saturated fatty acid ratio and high fiber content induced numerous favorable changes in coronary artery disease risk factors in hypercholesterolemic men, regardless of the protein source.

Clinical relevance of the biochemical, metabolic, and genetic factors that influence low-density lipoprotein heterogeneity

Traditional risk factors for coronary artery disease (CAD) predict about 50% of the risk of developing CAD. The Adult Treatment Panel (ATP) III has defined emerging risk factors for CAD, including small, dense low-density lipoprotein (LDL). Small, dense LDL is often accompanied by increased triglycerides (TGs) and low high-density lipoprotein (HDL). An increased number of small, dense LDL particles is often missed when the LDL cholesterol level is normal or borderline elevated. Small, dense LDL particles are present in families with premature CAD and hyperapobetalipoproteinemia, familial combined hyperlipidemia, LDL subclass pattern B, familial dyslipidemic hypertension, and syndrome X. The metabolic syndrome, as defined by ATP III, incorporates a number of the components of these syndromes, including insulin resistance and intra-abdominal fat. Subclinical inflammation and elevated procoagulants also appear to be part of this atherogenic syndrome. Overproduction of very low-density lipoproteins (VLDLs) by the liver and increased secretion of large, apolipoprotein (apo) B-100-containing VLDL is the primary metabolic characteristic of most of these patients. The TG in VLDL is hydrolyzed by lipoprotein lipase (LPL) which produces intermediate-density lipoprotein. The TG in intermediate-density lipoprotein is hydrolyzed further, resulting in the generation of LDL. The cholesterol esters in LDL are exchanged for TG in VLDL by the cholesterol ester tranfer proteins, followed by hydrolysis of TG in LDL by hepatic lipase which produces small, dense LDL. Cholesterol ester transfer protein mediates a similar lipid exchange between VLDL and HDL, producing a cholesterol ester-poor HDL. In adipocytes, reduced fatty acid trapping and retention by adipose tissue may result from a primary defect in the incorporation of free fatty acids into TGs. Alternatively, insulin resistance may promote reduced retention of free fatty acids by adipocytes. Both these abnormalities lead to increased levels of free fatty acids in plasma, increased flux of free fatty acids back to the liver, enhanced production of TGs, decreased proteolysis of apo B-100, and increased VLDL production. Decreased removal of postprandial TGs often accompanies these metabolic abnormalities. Genes regulating the expression of the major players in this metabolic cascade, such as LPL, cholesterol ester transfer protein, and hepatic lipase, can modulate the expression of small, dense LDL but these are not the major defects. New candidates for major gene effects have been identified on chromosome 1. Regardless of their fundamental causes, small, dense LDL (compared with normal LDL) particles have a prolonged residence time in plasma, are more susceptible to oxidation because of decreased interaction with the LDL receptor, and enter the arterial wall more easily, where they are retained more readily. Small, dense LDL promotes endothelial dysfunction and enhanced production of procoagulants by endothelial cells. Both in animal models of atherosclerosis and in most human epidemiologic studies and clinical trials, small, dense LDL (particularly when present in increased numbers) appears more atherogenic than normal LDL. Treatment of patients with small, dense LDL particles (particularly when accompanied by low HDL and hypertriglyceridemia) often requires the use of combined lipid-altering drugs to decrease the number of particles and to convert them to larger, more buoyant LDL. The next critical step in further reduction of CAD will be the correct diagnosis and treatment of patients with small, dense LDL and the dyslipidemia that accompanies it.

The cardioprotective effect of wine on human blood chemistry

We investigated the in vivo effects of regular consumption of red and white wine on the serum lipid profile, plasma plasminogen activator-1, homocysteine levels, and total antioxidant status. This study confirmed that moderate consumption of wine, red more than white, exerts cardioprotective effects through beneficial changes in lipid profiles and plasma total antioxidant status.

Obesity, haemostasis and the fibrinolytic system

Obese patients are at risk for the development of cardiovascular diseases, which can in part be explained by disturbances in the haemostatic and fibrinolytic systems. Indeed, obese subjects tend to have higher values of fibrinogen, factor VII, factor VIII, von Willebrand factor and plasminogen activator inhibitor compared to non-obese subjects. Abdominal obesity, in particular, has been shown to be associated with disturbances in fibrinogen, factor VIII and von Willebrand factor, while less consistent results have been found for factor VII. Recently it has been demonstrated that the adipocyte itself is able to produce plasminogen activator inhibitor-1, possibly explaining the high levels found in obesity. Different studies have investigated the association between haemostatic and fibrinolytic parameters and the insulin resistance syndrome, often present in obese subjects. Fibrinogen has been found to be related to insulin, but it has been suggested that this relationship is not independent of the accompanying inflammatory reaction. Results from studies on the relationship between insulin resistance and factor VII, factor VIII and von Willebrand factor levels are inconsistent. In contrast, plasminogen activator inhibitor-1 has been found to correlate with all components of the insulin resistance syndrome, and can be considered as a true component of this metabolic syndrome. Weight loss seems to have a beneficial effect on factor VII--probably mediated through a reduction in triglycerides. Data on factor VIII and von Willebrand factor are scarce but weight loss does not seem to have an effect. Fibrinogen does not seem to be reduced by modest weight loss and a more substantial weight loss seems necessary to lower fibrinogen levels. In contrast, both modest and substantial weight loss have been found to significantly reduce plasminogen activator inhibitor-1 levels. In conclusion, the increased cardiovascular risk observed in obesity could in part be explained by the association between insulin resistance and components of the fibrinolytic and haemostatic systems. Whether this relationship is truly causal or indirect needs to be elucidated further.

Elevated plasma activator inhibitor 1 is not related to insulin resistance and to gene polymorphism in healthy centenarians

Previous studies demonstrated a relationship between the degree of insulin resistance and plasma plasminogen activator inhibitor type-1 (PAI-1) levels. We aim at investigating the relationship between the degree of insulin resistance and plasma PAI-1 levels in aged subjects (n=83) and in healthy centenarians (n=42). In all subjects the degree of insulin resistance was assessed by HOMA method. Our data demonstrated that healthy centenarians have higher plasma PAI-1 levels (73.1+/-13.9 vs 23.7+/-14.7 ng/ml, P<0.001) and lower degree of insulin resistance (1.4+/-0.5 vs 3.3+/-1.3, P<0.001) than aged subjects. In aged subjects plasma PAI-1 levels correlated with the degree of insulin resistance (r=0.61, P<0.001), fasting plasma triglycerides (r=0.74, P<0.001) and age (r=0.33, P<0.001). All such associations were lost in centenarians. Plasma PAI-1 Ag levels were also similar in aged subjects and centenarians even after categorization for PAI gene polymorphism. In multivariate analysis, a model made by age, sex, body mass index, fasting plasma triglycerides, HOMA and PAI-1 gene explained 65 and 50% of plasma PAI-1 level variations in aged subjects and centenarians, respectively. Nevertheless, HOMA (P<0.001) was significantly and independently associated with plasma PAI-1 levels only in aged subjects. In conclusion, our data demonstrates that in healthy centenarians, plasma PAI-1 were not associated with the degree of insulin resistance as in aged subjects. Frequency of PAI-1 genotype does not provide an explanation for such differences between aged subjects and centenarians.

Improvements in cardiovascular risk profile with large-volume liposuction: a pilot study

In this study, the authors investigated the physiologic effects of the altered body composition that results from surgical removal of large amounts of subcutaneous adipose tissue. Fourteen women with body mass indexes of greater than > 27 kg/m2 underwent measurements of fasting plasma insulin, triglycerides, cholesterol, body composition by dual-energy x-ray absorptiometry (DXA), resting energy expenditure, and blood pressure before and after undergoing large-volume ultrasound-assisted liposuction. There were no significant intraoperative complications. Body weight had decreased by 5.1 kg (p < 0.0001) by 6 weeks after liposuction, with an additional 1.3-kg weight loss (p < 0.05) observed between 6 weeks and 4 months after surgery, for a total weight loss of 6.5 kg (p < 0.00006). Body mass index decreased from (mean +/- SEM) 28.8 +/- 2.3 to 26.8 +/- 1.5 kg/m2 (p < 0.0001). This change in body weight was primarily the result of decreases in body fat mass: as assessed by DXA, lean body mass did not change (43.8 +/- 3.1 kg to 43.4 +/- 3.6 kg, p = 0.80), whereas DXA total body fat mass decreased from 35.7 +/- 6.3 to 30.1 +/- 6.5 kg (p < 0.0001). There were significant decreases in fasting plasma insulin levels (14.9 +/- 6.5 mIU/ml before liposuction versus 7.2 +/- 3.2 mIU/ml 4 months after liposuction, p < 0.007), and systolic blood pressure (132.1 +/- 7.2 versus 120.5 +/- 7.8 mmHg, p < 0.0002). Total cholesterol, high-density lipoprotein cholesterol, plasma triglycerides, and resting energy expenditure values were not significantly altered after liposuction. In conclusion, over a 4-month period, large-volume liposuction decreased weight, body fat mass, systolic blood pressure, and fasting insulin levels without detrimental effects on lean body mass, bone mass, resting energy expenditure, or lipid profiles. Should these improvements be maintained over time, liposuction may prove to be a valuable tool for reducing the comorbid conditions associated with obesity.

Hypothalamic-pituitary-adrenal axis function and the metabolic syndrome X of obesity

Obesity has negative health consequences related to fat distribution, particularly the central or visceral accumulation of fat. The major complications associated with visceral obesity, termed the "Metabolic Syndrome of Obesity," or "Syndrome X," are type II diabetes, hypertension, and dyslipidemia. As with certain mood disorders, the syndrome may be a consequence of neuroendocrine perturbations typically associated with chronic stress. Our work with bonnet macaque monkeys provides an animal model for the relationship between early stress, behavioral and hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and Syndrome X. During their infant's first half-year, mothers face a variable foraging demand (VFD), in which ample food varies unpredictably in the difficulty of its acquisition, and the offspring show persistent abnormalities in systems known to modulate stress and affective regulation. Early work on the bonnet macaque noted the emergence of a sample of spontaneously obese subjects as they matured. Using the VFD model, the current study showed that there was a clear relationship between early cerebrospinal fluid corticotropin-releasing factor levels and subsequently measured body mass index, supporting the hypotheses regarding the interactive roles of early experience and HPA axis dysregulation in the ontogeny of both metabolic and mood disorders.

Therapeutic modulation of low-density lipoprotein size

Small, dense LDL particles have been linked to atherosclerosis, often in a cluster of risk factors and affecting approximately 20% of adults. Over the past year, studies confirmed that small dense LDL is an autosomal dominant trait, influenced mainly by hypertriglyceridaemia and obesity, insulin resistance and diabetes mellitus and some incompletely investigated genetic loci. Compositional and functional differences have been observed in small LDL. Evidence is emerging that lifestyle as well as pharmacological intervention can modulate LDL size, but there is no proof yet that this is of clinical benefit.