Effects of fenofibrate on endothelial function and cell adhesion molecules during post-prandial lipemia in hypertriglyceridemia

Chylous aqueous humor caused by hyperlipidemia: A case report and literature review

RATIONALE

Generally, there is no lipoprotein in aqueous humor, and chyle usually exists transiently in the body. Therefore, persistent chylous aqueous humor is rare.

PATIENT CONCERNS

We report a case of a 39-year-old man with persistent milky white appearance over the right eye.

DIAGNOSES

The patient had a history of poorly controlled diabetes for the past 2 years and central retinal vein occlusion of the same eye for the past 2 weeks. The patient's right eye had a uniform milky appearance in the anterior chamber, transparent cornea, and no keratic precipitate in the posterior cornea. Color Doppler ultrasound of the affected eye showed no obvious inflammation in the vitreous cavity. Laboratory tests revealed severe chylemia. The patient was finally diagnosed as chylous aqueous humor.

INTERVENTIONS AND OUTCOMES

After conventional hypolipidemia and hypoglycemia treatment and locally glucocorticoid treatment. The milky white changes in the anterior chamber improved considerably and finally disappeared.

LESSONS

Although the impact of hyperlipidemia on the cardiovascular system and digestive system is well known, its impact on the eyes is often overlooked. We report a rare case of unilateral chylous aqueous humor caused by hyperlipidemia. Through the analysis of this special case, we recommend that ophthalmologists should pay attention to the impact of blood lipid change on eyes.

A single, high-fat meal adversely affects postprandial endothelial function: a systematic review and meta-analysis

BACKGROUND

Endothelial dysfunction is a predictive risk factor for the development of atherosclerosis and is assessed by flow-mediated dilation (FMD). Although it is known that NO-dependent endothelial dysfunction occurs after consuming a high-fat meal, the magnitude of the effect and the factors that affect the response are unquantified.

OBJECTIVES

We conducted a systematic review and meta-analysis exploring the quantitative effects of a single high-fat meal on endothelial function and determined the factors that modify the FMD response.

METHODS

Six databases were systematically searched for original research published up to January 2022. Eligible studies measured fasting and postprandial FMD following consumption of a high-fat meal. Meta-regression was used to analyze the effect of moderator variables.

RESULTS

There were 131 studies included, of which 90 were suitable for quantitative meta-analysis. A high-fat meal challenge transiently caused endothelial dysfunction, decreasing postprandial FMD at 2 hours [-1.02 percentage points (pp); 95% CI: -1.34 to -0.70 pp; P < 0.01; I2 = 93.3%], 3 hours [-1.04 pp; 95% CI: -1.48 to -0.59 pp; P < 0.001; I2 = 84.5%], and 4 hours [-1.19 pp; 95% CI: -1.53 to -0.84 pp; P < 0.01; I2 = 94.6%]. Younger, healthy-weight participants exhibited a greater postprandial reduction in the FMD percentage change than older, heavier, at-risk groups after a high-fat meal ( P < 0.05). The percentage of fat in the meals was inversely associated with the magnitude of postprandial changes in FMD at 3 hours (P < 0.01).

CONCLUSIONS

A single, high-fat meal adversely impacts endothelial function, with the magnitude of the impact on postprandial FMD moderated by the fasting FMD, participant age, BMI, and fat content of the meal. Recommendations are made to standardize the design of future postprandial FMD studies and optimize interpretation of results, as high-fat meals are commonly used in clinical studies as a challenge to assess endothelial function and therapeutics. This trial was registered at PROSPERO as CRD42020187244.

Neurovascular protection by peroxisome proliferator-activated receptor α in ischemic stroke

Ischemic stroke is a leading cause of death and disability worldwide. Currently, the only pharmacological therapy for ischemic stroke is thrombolysis with tissue plasminogen activator that has a narrow therapeutic window and increases the risk of intracerebral hemorrhage. New pharmacological treatments for ischemic stroke are desperately needed, but no neuroprotective drugs have successfully made it through clinical trials. Beneficial effects of peroxisome proliferator-activated receptor alpha (PPARα) activation on vascular integrity and function have been reported, and PPARα agonists have clinically been used for many years to manage cardiovascular disease. Thus, PPARα has gained interest in recent years as a target for neurovascular disease such as ischemic stroke. Accumulating preclinical evidence suggests that PPARα activation modulates several pathophysiological hallmarks of stroke such as oxidative stress, blood-brain barrier (BBB) dysfunction, and neuroinflammation to improve functional recovery. Therefore, this review summarizes the various actions PPARα exerts in neurovascular health and disease and the potential of employing exogenous PPARα agonists for future pharmacological treatment of ischemic stroke.

Circular RNA Expression Profiles in Vaginal Epithelial Tissue of Women With Lubrication Disorders

INTRODUCTION

Recently, circular RNA (circRNA) has been proved to occupy a vital pathological position in many diseases by acting as microRNAs sponges. However, the role of circRNA in female sexual dysfunction (FSD), especially in lubrication disorders (LDs), remains unclear.

AIM

The aim of this study was to detect circRNA expression in LDs, analyzed target genes, and pathways regulated by the differently expressed circRNAs.

METHODS

In this study, next-generation sequencing was first conducted to produce circRNA expression profiles of FSD groups and normal control groups. Furthermore, differences in expression of 6 randomly selected circRNAs were confirmed through real-time quantitative polymerase chain reaction. Kyoto Encyclopedia of Genes and Genomes biological pathway analysis and Gene Ontology showed that immune processes and infection could be involved in the development of FSDs.

MAIN OUTCOME MEASURE

CircRNA expression in vaginal epithelial tissue obtained from women with LDs have been detected. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes biological pathway analysis, and circRNA-microRNA interaction predictions were investigated.

RESULTS

Totally, 7,746 circRNAs of vaginal epithelial tissue from women of 2 groups were sequenced. Preliminary judgment revealed that there were 73 circRNAs that have significant differential expression, including 53 downregulated circRNAs and 20 upregulated circRNAs. Research results also displayed that the majority of circRNAs has multiple binding sites of microRNAs, including miR-137, which has been reported to be linked to FSD.

CLINICAL IMPLICATIONS

We predicted 10 circRNAs paired with hsa-miR-137-5p, but the mechanism of circRNA involvement in disease development remains to be further explored.

STRENGTHS & LIMITATIONS

For the first time, the research disclosed the potential pathogenesis of LDs. However, we only analyzed the expression profile of circRNA in FSD, no specific mechanism was further confirmed or proposed. We still have a preliminary understanding, and more research is needed to explore the target of FSD treatment.

CONCLUSION

The results suggest that circRNAs have different expression in the FSD groups and play a vital part in the occurrence and development of FSD. Zhang J, Xia H, Zhang A, et al. Circular RNA Expression Profiles in Vaginal Epithelial Tissue of Women With Lubrication Disorders. J Sex Med 2019;16:1696-1707.

The Role of Mesenchymal Stem Cells in Atherosclerosis: Prospects for Therapy via the Modulation of Inflammatory Milieu

Atherosclerosis is a chronic, inflammatory disease that mainly affects the arterial intima. The disease is more prevalent in middle-age and older individuals with one or more cardiovascular risk factors, including dyslipidemia, hypertension, diabetes, smoking, obesity, and others. The beginning and development of atherosclerosis has been associated with several immune components, including infiltration of inflammatory cells, monocyte/macrophage-derived foam cells, and inflammatory cytokines and chemokines. Mesenchymal stem cells (MSCs) originate from several tissue sources of the body and have self-renewal and multipotent differentiation characteristics. They also have immunomodulatory and anti-inflammatory properties. Recently, it was shown that MSCs have a regulatory role in plasma lipid levels. In addition, MSCs have shown to have promising potential in terms of treatment strategies for several diseases, including those with an inflammatory component. In this regard, transplantation of MSCs to patients with atherosclerosis has been proposed as a novel strategy in the treatment of this disease. In this review, we summarize the current advancements regarding MSCs for the treatment of atherosclerosis.

Emerging roles for high-density lipoproteins in neurodegenerative disorders

Lipoproteins are the complexes of different lipids and proteins, which are devoted to the transport and clearance of lipids or lipid-related molecules in the circulation. Lipoproteins have been found to play a crucial role in brain function and may influence myelination process. Among lipoproteins, high-density lipoproteins (HDLs) and their major protein component, apoA-I, are directly involved in cholesterol efflux in the brain. It has been suggested that inadequate or dysfunctional brain HDLs may contribute to cerebrovascular dysfunctions, neurodegeneration, or neurovascular instability. HDL deficiency could also promote cognitive decline through impacting on atherosclerotic risk. The focus of this review is to discuss knowledge on HDL dysregulation in neurological disorders. A better understanding on how changes in cellular HDL and apolipoprotein homeostasis affect central nervous system function may provide promising novel avenues for the treatment of specific HDL-related neurological disorders.

A review of the anti-inflammatory properties of antidiabetic agents providing protective effects against vascular complications in diabetes

The global prevalence of Type 2 diabetes mellitus and its associated complications are growing rapidly. Although the role of hyperglycemia is well recognized in the pathophysiology of diabetic complications, its exact underlying mechanisms are not fully understood. In this regard, accumulating evidence suggests that the role of inflammation appears pivotal, with studies showing that most diabetic complications are associated with an inflammatory response. Several classes of antidiabetic agents have been introduced for controlling glycemia, with evidence that these pharmacological agents may have modulatory effects on inflammation beyond their glucose-lowering activity. Here we review the latest evidence on the anti-inflammatory effects of commonly used antidiabetic medications and discuss the relevance of these effects on preventing diabetic complications.

Fenofibrate in cancer: mechanisms involved in anticancer activity

Objective: To review the mechanisms of anti-cancer activity of fenofibrate (FF) and other Peroxisome Proliferator Activator Receptor α (PPARα) agonists based on evidences reported in the published literature.Methods: We extensively reviewed the literature concerning FF as an off target anti-cancer drug. Controversies regarding conflicting findings were also addressed.Results: The main mechanism involved in anti-cancer activity is anti-angiogenesis through down-regulation of  Vascular Endothelial Growth Factor (VEGF), Vascular Endothelial Growth Factor Receptor (VEGFR) and Hypoxia Inducible factor-1 α (HIF-1α), inhibition of endothelial cell migration, up-regulation of endostatin and thrombospondin-1, but there are many other contributing mechanisms like apoptosis and cell cycle arrest, down-regulation of Nuclear Factor Kappa B (NF-kB) and Protein kinase B (Akt) and decrease of cellular energy by impairing mitochondrial function. Growth impairment is related to down-regulation of Phospho-Inositol 3 Kinase (PI3K)/Akt axis and down-regulation of the p38 map kinase (MAPK) cascade. A possible role should be assigned to FF stimulated over-expression of Tribbles Homolog-3 (TRIB3) which inhibits Akt phosphorylation. Important anti-cancer and anti-metastatic activities are due to down-regulation of MCP-1 (monocyte chemotactic protein-1), decreased Metalloprotease-9 (MMP-9) production, weak down-regulation of adhesion molecules like E selectin, intercellular adhesion molecules (ICAM) and Vascular Endothelial Adhesion Molecules (VCAM), and decreased secretion of chemokines like Interleukin-6 (IL-6), and down-regulation of cyclin D-1. There is no direct link between FF activity in lipid metabolism and anticancer activity, except for the fact that many anticancer actions are dependent from PPARα agonism. FF exhibits also PPARα independent anti-cancer activities.Conclusions: There are strong evidences indicating that FF can disrupt growth-related activities in many different cancers, due to anti-angiogenesis and anti-inflammatory effects. Therefore FF may be useful as a complementary adjunct treatment of cancer, particularly included in anti-angiogenic protocols like those currently increasingly used in glioblastoma. There are sound reasons to initiate well planned phase II clinical trials for FF as a complementary adjunct treatment of cancer.

Effects of the n-6/n-3 polyunsaturated fatty acids ratio on postprandial metabolism in hypertriacylglycerolemia patients

Background

Atherosclerosis is a postprandial phenomenon. The balanced n-6/n-3 PUFA ratio contributing to the prevention of atherosclerosis has been well shown, but the effect of the ratio on postprandial metabolism has not been fully investigated. The aim of this study was to investigate the effects of the n-6/n-3 PUFAs ratio on postprandial metabolism in hypertriacylglycerolemia patients, comparing them to healthy controls.

Methods

Test meals with 0.97 (high n-3) and 8.80 (low n-3) n-6/n-3 PUFAs ratio were administered in a randomized crossover design to 8 healthy and 8 hypertriacylglycerolemia subjects. Blood samples were collected for 8 hours after meals to measure triglyceride (TG), total cholesterol (TC), HDL, ApoA, ApoB, glucose, insulin, inflammatory makers including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), endothelial function including nitric oxide (NO) and endothelin-1 (ET-1).

Results

According to repeated–measures ANOVA, the postprandial response of lipid, glucose, insulin, inflammation and endothelial function were not significantly different between meals. The postprandial TG and NO response were significantly different between healthy control (HC) and hypertriglyceridemia group (HTG) after both meals (P < 0.01). After both meals maximal change and iAUC for TG was all higher in HTG group than HC group, the difference was significant after low n-3 meal but not after high n-3 meal. The concentration of glucose, insulin, IL-6, TNFα and ET-1 at each time point was higher and NO was lower in HTG group, but the maximal change and iAUC had no significant difference except for iAUC of insulin, IL-6 and diAUC of NO after low n-3 meal.

Conclusions

The ratio of n-6 and n-3 maybe do not acutely influence the postprandial metabolism, inflammatory response and endothelial function, but the low n-3 meal can strengthen the difference between HTG and HC group.

The efficacy of Ezetimibe added to ongoing Fibrate-Statin therapy on postprandial lipid profile in the patients with type 2 Diabetes mellitus

BACKGROUND

Postprandial hypertriglyceridemia in diabetes mellitus can be followed by endothelial dysfunction, impaired vascular compliance and increased cardiovascular complications. So focus on better control of postprandial hypertriglyceridemia is as important as controlling fasting triglyceride level in type 2 DM.

OBJECTIVE

We evaluated the effect of ezetimibe adding to fibrate or statin on postprandial hypertriglyceridemia.

METHODS

In a randomized controlled clinical trial, 47 subjects with type 2 diabetes and hypertiglyceridemia were enrolled and divided in three treatment groups including Gemfibrozil 1200mg/d + placebo(group A), Ezetimibe10mg/d + Gemfibrozile 1200mg/d(group B) or Ezetimibe10mg/d + Atorvastatin10mg/d (group C) for a 6- week period. Oral fat loading test were performed in the initiation and also at the end of the study and lipid profile and APOB were measured.

RESULTS

Fasting and postprandial serum triglyceride (TG) decreased significantly with all the three treatment groups with no difference between them in the percent of TG reduction. Although serum total cholesterol decreased significantly in all the three groups of treatment its reduction was more prominent in group C(-38.1% ± 11.2%in group C vs. -16.5% ± 19.6% and -7.2% ± 10.7% in groups B & A respectively, p < 0.0001 ). Fasting serum HDL increased significantly only by Gemfibrozil (23.4% ± 28.4% vs. 6.4% ± 18.9% and 1.8% ± 17.7%, p < 0.05 ). Fasting serum APOB was reduced only in ezetimibe containing groups (B &C).

CONCLUSION

Adding ezetimibe to gemfibrozil has no additional effect on reducing postprandial TG but ezetimibe can potentiate the effect of low-dose atorvastatin on lowering TG and LDL-c.

Exchanging saturated fatty acids for (n-6) polyunsaturated fatty acids in a mixed meal may decrease postprandial lipemia and markers of inflammation and endothelial activity in overweight men

Postprandial lipemia, low-grade systemic inflammation, and endothelial activity are related to metabolic disorders. It is well known that dietary fatty acid composition modulates postprandial lipemia, but information on the other metabolic risk markers is limited. We therefore studied the acute effects of a meal rich in SFA compared with those of a meal rich in (n-6) PUFA on postprandial responses in overweight men who are at an increased risk to develop the metabolic syndrome and its comorbidities. In a crossover design, the effects of 50 g butter (rich in SFA) on lipemia and markers for inflammation and endothelial activity were compared with those of 50 g sunflower oil [rich in (n-6) PUFA] during an 8-h postprandial mixed meal tolerance test in 13 overweight men. Postprandial changes in serum TG were comparable between the meals (P = 0.38), except for a reduction in the incremental area under the curve (P = 0.046) in the late postprandial phase after (n-6) PUFA (125 ± 96 mmol⋅min⋅L(-1)) compared with SFA (148 ± 98 mmol⋅min⋅L(-1)). Compared with the SFA meal, the (n-6) PUFA meal decreased plasma IL-6 (P = 0.003), TNFα (P = 0.005), soluble TNF receptors I and II (sTNFr; P = 0.024 and P < 0.001, respectively), and soluble vascular cell adhesion molecule-1 (sVCAM-1; P = 0.030) concentrations. These results indicate that exchanging SFA from butterfat for (n-6) PUFA in a mixed meal may decrease postprandial lipemia and concentrations of IL-6, TNFα, sTNFr-I and -II, and sVCAM-1 in overweight men.

Ezetimibe improves postprandial hyperlipemia and its induced endothelial dysfunction

OBJECTIVE

Postprandial hyperlipemia has been shown to impair endothelial function and contribute to the development of atherosclerosis. We investigated the association between postprandial lipid profiles and endothelial function, and we examined the effects of ezetimibe on postprandial hyperlipemia and lipemia-induced endothelial dysfunction.

METHODS

A randomized prospective trial in which 10 mg/day of ezetimibe was administered to 10 subjects for 4 weeks and not administered to 10 subjects (control group) was performed. Lipid profiles and endothelial function, assessed by brachial artery flow-mediated dilation (FMD) during a fasting state and at 2, 4, 6 and 8 h after an oral cookie loading test, were determined before and after treatment for 4 weeks.

RESULTS

In all subjects before treatment, the maximum reduction in postprandial %FMD was significantly correlated with the maximum increases in postprandial triglyceride (TG) (r=-0.499, P<0.05) and apolipoprotein B-48 (apoB-48) concentrations (r=-0.551, P<0.05). Ezetimibe treatment for 4 weeks significantly suppressed postprandial elevation in TG (area under the incremental curve, from 1419±594 to 968±32 1 mg h/dl, P<0.05), remnant lipoprotein cholesterol (from 66.9±27.6 to 38.9±15.4 mg h/dl, P<0.01) and apoB-48 (from 58.8±27.5 to 36.2±17.0 μg h/ml, P<0.05) concentrations, and postprandial endothelial dysfunction assessed by %FMD (maximum reduction in %FMD, from -2.6±1.1% to -1.2±0.8%, P<0.05), whereas no significant changes were observed in the control group.

CONCLUSION

Postprandial hyperlipemia is closely correlated with transient endothelial dysfunction. Ezetimibe improves postprandial hyperlipemia and its induced endothelial dysfunction.

The effect of combination therapy of allicin and fenofibrate on high fat diet-induced vascular endothelium dysfunction and liver damage in rats

Background

It is designed to investigate the effects of combination therapy of allicin and fenofibrate on the endothelial and liver functions in rats with hyperlipidemia.

Methods

The healthy male Wistar rats fed high fat diet were treated with fenofibrate (80 mg/kg per day) alone, allicin (60 mg/kg per day) alone and a lower dasage of combined therapy (allicin 20 mg/kg per day and fenofibrate 30 mg/kg per day) respectively for 8 weeks. The serum levels of cholesterol, triglyceride, nitrogen oxidative, alanine transferase (ALT) and aspartate transferase (AST) were determined. Acetylcholine-induced endothelium-dependent vascular relaxation (EDVR) of aorta rings was tested, and the morphologic changes of liver tissue were observed.

Results

Compared with high fat diet control, fenofibrate alone or the combined therapy increased remarkably the levels of high density lipoprotein respectively (P < 0.05). Both single and combined therapy of fenofibrate and allicin significantly enhanced the levels of NO (P < 0.01 or P < 0.05), but the combined therapy had greatest high EDVR responses (P < 0.01). Furthermore, the reduced levels of ALT and AST were significantly obvious in the combined therapy groups (P < 0.01 or P < 0.05). In addition, the lower dosage of combined therapy significantly ameliorated severe fatty degeneration of liver cells occurred in the high fat diet fed rat although the single fenofibrate treatment showed spotty necrosis of liver cells and bile duct expansion.

Conclusion

Combination therapy with allicin and fenofibrate can effectively enhance the protective effects on endothelial function and reduce the hepatic damage in rats with hyperlipidemia.

Fenofibrate reduces systemic inflammation markers independent of its effects on lipid and glucose metabolism in patients with the metabolic syndrome

CONTEXT

Fenofibrate is a peroxisome proliferator-activated receptor alpha agonist widely used in clinical practice, but its mechanism of action is incompletely understood.

OBJECTIVE

The aim of the study was to assess whether improvement in subclinical inflammation or glucose metabolism contributes to its antiatherogenic effects in insulin-resistant subjects with the metabolic syndrome (MetS).

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled study in the research unit at an academic center.

PATIENTS

We studied 25 nondiabetic insulin-resistant MetS subjects.

INTERVENTION(S)

We administered fenofibrate (200 mg/d) and placebo for 12 wk.

MAIN OUTCOME MEASURES

Before and after treatment, we measured plasma lipids/apolipoproteins, inflammatory markers (high-sensitivity C-reactive protein, IL-6, intercellular adhesion molecule/vascular cell adhesion molecule), adipocytokines (adiponectin, TNFalpha, leptin), and insulin secretion (oral glucose tolerance test). We also assessed adipose tissue, hepatic and peripheral (muscle) insulin resistance fasting and during a euglycemic insulin clamp with (3)H glucose and (14)C palmitate infusion combined with indirect calorimetry.

RESULTS

Subjects displayed severe insulin resistance and systemic inflammation. Fenofibrate significantly reduced plasma triglyceride, apolipoprotein (apo) CII, apo CIII, and apo E (all P < 0.01), with a modest increase in high-density lipoprotein-cholesterol (+12%; P = 0.06). Fenofibrate markedly decreased plasma high-sensitivity C-reactive protein by 49.5 +/- 8% (P = 0.005) and IL-6 by 29.8 +/- 7% (P = 0.03) vs. placebo. However, neither insulin secretion nor adipose tissue, hepatic or muscle insulin sensitivity or glucose/lipid oxidation improved with treatment. Adiponectin and TNF-alpha levels were also unchanged. Improvement in plasma markers of vascular/systemic inflammation was dissociated from changes in triglyceride/high-density lipoprotein-cholesterol, apo CII/CIII, or free fatty acid concentrations or insulin secretion/insulin sensitivity.

CONCLUSIONS

In subjects with the MetS, fenofibrate reduces systemic inflammation independent of improvements in lipoprotein metabolism and without changing insulin sensitivity. This suggests a direct peroxisome proliferator-activated receptor alpha-mediated effect of fenofibrate on inflammatory pathways, which may be important for the prevention of CVD in high-risk patients.

Gemfibrozil, stretching arms beyond lipid lowering

Gemfibrozil is long known for its ability to reduce the level of triglycerides in the blood circulation and to decrease the risk of hyperlipidemia. However, a number of recent studies reveal that apart from its lipid-lowering effects, gemfibrozil can also regulate many other signaling pathways responsible for inflammation, switching of T-helper cells, cell-to-cell contact, migration, and oxidative stress. In this review, we have made an honest attempt to analyze various biological activities of gemfibrozil and associated mechanisms that may help to consider this drug for different human disorders as primary or adjunct therapy.

Effect of prior exercise on postprandial lipemia and markers of inflammation and endothelial activation in normal weight and overweight adolescent boys

Postprandial lipemia (PPL) is associated with impaired endothelial function and inflammation. Acute exercise reduces PPL in adults. This investigation examined the effect of an acute bout of exercise on postprandial changes in triglycerides (TG), glucose, insulin, inflammation [white blood cell count (WBC), interleukin-6 (IL-6) tumor necrosis factor-alpha, C-reactive protein (CRP)] and endothelial activation [soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1)] following a high-fat meal in adolescents. Ten normal weight (NW) (BMI, 20.9 +/- 1.7 kg m(-2); 15.6 +/- 0.7 years) and eight overweight (OW) (BMI, 28.3 +/- 3.6 kg m(-2); 15.9 +/- 0.4 years) adolescent boys underwent two 6-h oral fat tolerance tests (OFTT) separated by 7-10 days. On the evening prior to each OFTT, subjects either rested or completed a treadmill exercise bout (65% V(O)(2max); 600 kcal expended). Exercise reduced (P < 0.01) the postprandial TG area under the curve by approximately 20% in the NW and OW groups. The postprandial glucose and insulin response did not differ between the control and exercise trials or between the NW and OW groups. Circulating leukocytes and plasma IL-6 levels increased (P < 0.01) in the NW and OW groups 6 h following the OFTT in both experimental conditions. There were no changes in CRP, sVCAM-1 or sICAM-1 following the OFTT and there were no differences between experimental condition or NW and OW groups. In conclusion, a moderate exercise bout prior to a high-fat meal effectively reduces postprandial TG concentrations to a similar degree in both NW and OW adolescents, but does not reduce the concomitant postprandial increase in WBC or IL-6.

Therapeutic effects of fibrates in postprandial lipemia

Hypertriglyceridemia is observed in many metabolic diseases such as the metabolic syndrome, diabetes mellitus, or mixed dyslipidemia frequently leading to premature coronary heart disease (CHD). Additionally, several studies have shown that postprandial hypertriglyceridemia is pronounced in patients with CHD, metabolic syndrome, hypertension, and other pathologic conditions. The triglyceride-rich lipoprotein remnants accumulating in the postprandial state seem to be involved in atherogenesis and in events leading to thrombosis. Since abnormal postprandial lipemia is associated with pathologic conditions, its treatment is of clinical importance.Fibrates are of significant help in managing hypertriglyceridemia. This review summarizes the effect of fibric acid derivatives on postprandial lipemia. Fibrates decrease the production of and enhance the catabolism of triglyceride-rich lipoproteins through the activation of peroxisome proliferator-activated receptor-alpha. Results of clinical studies with fibrates have confirmed their action in decreasing postprandial triglyceride levels by increasing lipoprotein lipase activity, decreasing apolipoprotein CIII production, and by increasing fatty acid oxidation in the liver.It is concluded that fibrates are effective agents in lowering the postprandial increase in remnant lipoprotein particles and retinyl palmitate. Furthermore, fibrates can also affect the postprandial lipid profile by increasing hepatic lipase levels and in some cases, by reducing cholesterol ester transfer protein activity. The main target of fibrate therapy is to improve fasting hypertriglyceridemia, which is an essential component associated with improving postprandial lipemia. Fibrates are well tolerated by patients and adverse effects have been reported rarely after their administration.

s-ICAM-1 and s-VCAM-1 in healthy men are strongly associated with traits of the metabolic syndrome, becoming evident in the postprandial response to a lipid-rich meal

Background

The importance of the postprandial state for the early stages of atherogenesis is increasingly acknowledged. We conducted assessment of association between postprandial triglycerides, insulin and glucose after ingestion of a standardized lipid-rich test meal, and soluble cellular adhesion molecules (sCAM) in young healthy subjects.

Methods

Metabolic parameters and sICAM-1, sVCAM-1 and E-selectin were measured before and hourly until 6 hours after ingestion of a lipid-rich meal in 30 healthy young men with fasting triglycerides <150 mg/dl and normal fasting glucose levels. Subjects were classified as either normal responders (NR) (postprandial triglyceride maxima < 260 mg/dl) or high responders (HR) (postprandial triglyceride maxima > 260 mg/dl). Levels of CAM were compared in HR and NR, and correlation with postprandial triglyceride, insulin and glucose response was assessed.

Results

Fasting sICAM-1 and sVCAM-1 levels were significantly higher in HR as compared to NR (p = 0.046, p = 0.03). For sE-selectin there was such a trend (p = 0.05). There was a strong positive and independent correlation between sICAM-1 and postprandial insulin maxima (r = 0.70, p < 0.001). sVCAM-1 showed significant correlation with postprandial triglycerides (AUC) (r = 0.37, p = 0.047). We found no correlation between sCAMs and fasting insulin or triglyceride concentrations.

Conclusion

This independent association of postprandial triglycerides with sICAM-1 may indicate a particular impact of postprandial lipid metabolism on endothelial reaction.

A meal rich in oleic acid beneficially modulates postprandial sICAM-1 and sVCAM-1 in normotensive and hypertensive hypertriglyceridemic subjects

This study investigated whether subjects with permanent activated endothelium have altered soluble forms of intercellular adhesion molecule 1 (sICAM-1) and vascular cell adhesion molecule 1 (sVCAM-1) postprandial response to a high-fat meal and whether this phenomenon is modulated by the nature of dietary fats. Twenty-eight hypertriglyceridemic (14 normotensives and 14 hypertensives) and 14 healthy male subjects were placed in a randomized and crossover design on diets enriched in refined olive oil (ROO) or high-palmitic sunflower oil (HPSO) for a 1-week lead-in period. Thereafter, subjects ate the corresponding fat-rich meal as a breakfast and underwent sampling hourly for 8 h. Plasma triglycerides (TG), sICAM-1 and sVCAM-1 were assayed. sICAM-1 and sVCAM-1 postprandial peak levels were significantly higher and occurred later in hypertriglyceridemic subjects (all P<.001) compared with healthy subjects. ROO meal resulted in smaller areas under the curve for sICAM-1 and sVCAM-1 in hypertriglyceridemic (normotensive and hypertensive) and healthy subjects compared to HPSO meal. Hypertension did not aggravate the postprandial response of TG, sICAM-1 and sVCAM-1. We conclude that the challenge of a meal with ROO appears to have a significant postprandial benefit on sICAM-1 and sVCAM-1 as surrogate markers of endothelial activation and vascular inflammation in healthy and more importantly in hypertriglyceridemic (normotensive and hypertensive) subjects.

Vascular and metabolic effects of treatment of combined hyperlipidemia: focus on statins and fibrates

Combined hyperlipidemia results from overproduction of hepatically synthesized apolipoprotein B in very low-density lipoproteins in association with reduced lipoprotein lipase activity. Thus, this condition is typically characterized by concurrent elevations in total cholesterol and triglycerides with decreased high-density lipoprotein cholesterol. High levels of apolipoprotein B-containing lipoproteins, most prominently carried by low-density lipoprotein (LDL) particles, are an important risk factor for coronary heart disease. Statin therapy is highly effective at lowering LDL cholesterol. Despite the benefits of statin treatment for lowering total and LDL cholesterol, many statin-treated patients still have initial or recurrent coronary heart disease events. In this regard, combined therapy with statins and fibrates is more effective in controlling atherogenic dyslipidemia in patients with combined hyperlipidemia than either drug alone. Furthermore, statins and fibrates activate PPARalpha in a synergistic manner providing a molecular rationale for combination treatment in coronary heart disease. Endothelial dysfunction associated with cardiovascular diseases may contribute to insulin resistance so that there may also be additional beneficial metabolic effects of combined statin/fibrates therapy. However, there has been little published evidence that combined therapy is synergistic or even better than monotherapy alone in clinical studies. Therefore, there is a great need to study the effects of combination therapy in patients. When statins are combined with gemfibrozil therapy, this is more likely to be accompanied by myopathy. However, this limitation is not observed when fenofibrate, bezafibrate, or ciprofibrate are used in combination therapy.

Endothelial function, arterial stiffness and lipid lowering drugs

The endothelium is a dynamic organ that plays a pivotal role in cardiovascular homeostasis. Alteration in endothelial function precedes the development of atherosclerosis and contributes to its initiation, perpetuation and clinical manifestations. It has been suggested that the assessment of endothelial function could represent a barometer of vascular health that could be used to gauge cardiovascular risk. This review summarises the various methods used to assess endothelium-dependent vasodilatation and their potential prognostic implications. In addition, the techniques used to evaluate arterial stiffness are discussed. The latter is to some extent controlled by the endothelium and has been the subject of considerable research in recent years. This paper also discusses the effects of lipid lowering treatment on both endothelial function and arterial stiffness.

Fenofibrate therapy ameliorates fasting and postprandial lipoproteinemia, oxidative stress, and the inflammatory response in subjects with hypertriglyceridemia and the metabolic syndrome

OBJECTIVE

The aim of this study was to determine the effects of fenofibrate (160 mg/day) on fasting and postprandial lipoproteins, oxidized fatty acids, and inflammatory mediators in subjects with hypertriglyceridemia and the metabolic syndrome.

RESEARCH DESIGN AND METHODS

Fifty-nine subjects with fasting hypertriglyceridemia (> or = 1.7 and < 6.9 mmol/l) and two or more of the Adult Treatment Panel III criteria for the metabolic syndrome were randomly assigned to fenofibrate (160 mg/day) or placebo in a double-blind, controlled clinical trial.

RESULTS

Fenofibrate treatment lowered fasting triglycerides (-46.1%, P < 0.0001) and postprandial (area under the curve) triglycerides (-45.4%, P < 0.0001) due to significant reductions in postprandial levels of large (-40.8%, P < 0.0001) and medium (-49.5%, P < 0.0001) VLDL particles. The number of fasting total LDL particles was reduced in fenofibrate-treated subjects (-19.0%, P = 0.0033) primarily due to reductions in small LDL particles (-40.3%, P < 0.0001); these treatment differences persisted postprandially. Fasting and postprandial oxidized fatty acids were reduced in fenofibrate-treated subjects compared with placebo-administered subjects (-15.3%, P = 0.0013, and 31.0%, P < 0.0001, respectively), and fenofibrate therapy lowered fasting and postprandial soluble vascular cell adhesion molecule-1 (VCAM-1) (-10.9%, P = 0.0005, and -12.0%, P = 0.0001, respectively) as well as fasting and postprandial soluble intercellular adhesion molecule-1 (ICAM-1) (-14.8%, P < 0.0001, and -15.3%, P < 0.0001, respectively). Reductions in VCAM-1 and ICAM-1 were correlated with reductions in fasting and postprandial large VLDL particles (P < 0.0001) as well as postprandial oxidized fatty acids (P < 0.0005).

CONCLUSIONS

Triglyceride-lowering therapy with fenofibrate reduced fasting and postprandial free fatty acid oxidation and inflammatory responses, and these antiatherosclerotic effects were most highly correlated with reductions in large VLDL particles.

Vascular inflammation in hypertension and diabetes: molecular mechanisms and therapeutic interventions

More than 80% of patients with type 2 diabetes mellitus develop hypertension, and approx. 20% of patients with hypertension develop diabetes. This combination of cardiovascular risk factors will account for a large proportion of cardiovascular morbidity and mortality. Lowering elevated blood pressure in diabetic hypertensive individuals decreases cardiovascular events. In patients with hypertension and diabetes, the pathophysiology of cardiovascular disease is multifactorial, but recent evidence points toward the presence of an important component dependent on a low-grade inflammatory process. Angiotensin II may be to a large degree responsible for triggering vascular inflammation by inducing oxidative stress, resulting in up-regulation of pro-inflammatory transcription factors such as NF-kappaB (nuclear factor kappaB). These, in turn, regulate the generation of inflammatory mediators that lead to endothelial dysfunction and vascular injury. Inflammatory markers (e.g. C-reactive protein, chemokines and adhesion molecules) are increased in patients with hypertension and metabolic disorders, and predict the development of cardiovascular disease. Lifestyle modification and pharmacological approaches (such as drugs that target the renin-angiotensin system) may reduce blood pressure and inflammation in patients with hypertension and metabolic disorders, which will reduce cardiovascular risk, development of diabetes and cardiovascular morbidity and mortality.

Gypenoside XLIX, a naturally occurring PPAR-alpha activator, inhibits cytokine-induced vascular cell adhesion molecule-1 expression and activity in human endothelial cells

Vascular cell adhesion molecule-1 (VCAM-1) is involved in several diseases, including chronic inflammation and atherosclerosis. Inhibition of the expression of this adhesion molecule is one of the key targets of anti-inflammatory, anti-cancer and anti-atherosclerotic drugs. Gynostemma pentaphyllum is a traditional medicine widely used in the treatment of respiratory inflammation, hyperlipidemia and atherosclerosis. However, its molecular mechanisms of action are still largely unknown. Gypenoside XLIX, a dammarane-type glycoside, is a prominent component of G. pentaphyllum. We have recently demonstrated Gypenoside XLIX to be a selective peroxisome proliferator-activated receptor (PPAR)-alpha activator. Here we demonstrate that Gypenoside XLIX concentration-dependently (0-300 microM) inhibited VCAM-1 promoter activity after induction by cytokine tumor necrosis factor (TNF)-alpha in human umbilical vein endothelial cells (HUVECs) transfected with promoter-reporter construct pVCAM-1-LUC. Furthermore, Gypenoside XLIX inhibited TNF-alpha-induced VCAM-1 mRNA and protein overexpression in HUVECs. The result of the enzyme immunoassay demonstrated that Gypenoside XLIX inhibited TNF-alpha-induced increase in cell surface VCAM-1 protein levels in HUVECs. In the present study we show that activities of Gypenoside XLIX are similar to those of Wy-14643, a potent synthetic PPAR-alpha activator. Furthermore, Gypenoside XLIX-induced inhibition on TNF-alpha-stimulated VCAM-1 promoter hyperactivity was completely abolished by a selective blocker of PPAR-alpha, MK-886. Thus, our findings suggest that Gypenoside XLIX inhibits cytokine-induced VCAM-1 overexpression and hyperactivity in human endothelial cells via a PPAR-alpha-dependent pathway. These data provide new insight into the rational basis of the use of the traditional Chinese herbal medicine G. pentaphyllum in the treatment of inflammatory and cardiovascular diseases, including atherosclerosis.

Inflammation in diabetes mellitus: role of peroxisome proliferator-activated receptor-alpha and peroxisome proliferator-activated receptor-gamma agonists

Patients with type 2 diabetes mellitus and/or the metabolic syndrome have considerable cardiovascular risk. Treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and with antihypertensive and some antihyperglycemic agents reduces this risk, but residual macrovascular morbidity and mortality persist, even in patients assigned to intensive multifactorial intervention programs. Therapeutic strategies that target inflammation and lipid abnormalities not well addressed by statins may offer additional opportunities for improving the prognosis of these patients. Inflammation, a key mechanism of atherogenesis, appears to have particular relevance to diabetic vascular complications, as well as in the development of diabetes itself. Oxidative stress and hyperglycemia also figure among the pathogenic factors that promote cardiovascular complications in patients with the metabolic syndrome and/or diabetes and may augment the ongoing inflammation. Peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma, members of the nuclear receptor family, form ligand-activated transcription factors that regulate key important metabolic pathways. PPARs have become therapeutic targets through the use of the fibrate class of antidyslipidemic drugs (PPAR-alpha) and the insulin-sensitizing thiazolidinediones (PPAR-gamma). The activation of these PPARs may also suppress inflammation and atherosclerosis. Recent clinical trials (Fenofibrate Intervention and Event Lowering in Diabetes [FIELD], Prospective Pioglitazone Clinical Trial in Macrovascular Events [PROactive]) have considered the impact of these PPAR agonists on cardiovascular disease, with mixed effects that require careful analysis, especially given ongoing trials and additional PPAR agonists in development.

Effect of carvedilol on portal hypertension depends on the degree of endothelial activation and inflammatory changes

OBJECTIVE

Bleeding from esophageal varices is a major complication of liver cirrhosis. Non-selective beta-blockers exert an influence on the functional part of portal hypertension, thereby reducing the risk of bleeding. Direct measurement of this functional part is not possible; nevertheless, pro-inflammatory markers as well as parameters of endothelial dysfunction might serve as surrogate markers. The aim of study was to assess the correlation between the therapeutic efficacy of carvedilol and markers of endothelial dysfunction and systemic inflammation in patients with liver cirrhosis and portal hypertension.

MATERIAL AND METHODS

Thirty-six patients with cirrhosis and portal hypertension were given carvedilol, 25 mg q.i.d. for 30 days. Hepatic venous pressure gradient (HVPG) and biochemical determinations were performed prior to and after the treatment. Eight healthy individuals served as controls for comparison of biochemical markers.

RESULTS

In the whole group of cirrhotic patients, HVPG decreased from 17.7+/-3.8 to 14.9+/-4.8 mmHg (p<0.001). Complete response was seen in 15 patients (42%). Baseline serum levels of E-selectin were significantly higher in responders than in non-responders (119.8+/-70.6 versus 52.6+/-25.7 ng/ml; p=0.023) and in controls (28.8+/-22.2 ng/ml; p=0.004). Furthermore, baseline TNF-alpha levels were significantly higher in responders than in non-responders (22.8+/-15.7 versus 7+/-8.9; p=0.047) and in controls (5.5+/-5.9 pg/ml; p=0.005). Serum levels of ICAM-1 showed the same trend (4360+/-2870 versus 2861+/-1577 versus 651+/-196 ng/ml), although differences did not reach statistical significance.

CONCLUSIONS

Markers of systemic inflammation and endothelial dysfunction seem to predict the hypotensive effect of carvedilol on portal hypertension in patients with liver cirrhosis and may be useful in the assessment of the efficacy of the therapy.

Postprandial lipaemia in menopausal women with metabolic syndrome

BACKGROUND

The metabolic syndrome (MetS) is associated with an increased incidence of coronary heart disease (CHD). Postprandial hypertriglyceridaemia is also associated with CHD. The aim of this study was to evaluate the postprandial lipaemia after an oral fat tolerance test (OFTT) in women with MetS.

METHODS

OFTT, was given to 21 menopausal women with MetS (defined by the Adult Treatment Panel III) and to 12 healthy menopausal women. Triglyceride (TG) levels were measured before and 2, 4, 6 and 8h after the OFTT. The postprandial response was quantified by the areas under the curve (AUC) of TG levels. MetS women were subdivided according to body mass index (BMI) < or > or =30kg/m(2), and to fasting TG levels < or > or =150mg/dl.

RESULTS

The response to the OFTT was significantly higher in the MetS group compared to healthy [AUC(S.D.), in mg/dl/h; 2014(933) versus 732(197), p<0.001]. The subjects with BMI < or > or =30kg/m(2) had similar fasting TG levels [157(60)mg/dl versus 158(67) mg/dl] and AUC [1975(898) versus 2072(1044), respectively]. The MetS women with TG> or =150mg/dl had higher AUC compared to those with TG<150mg/dl [2502(854) versus 1281(441), p=0.002]. In linear regression analysis, where BMI, high-density lipoprotein cholesterol, fasting TG, HOMA-IR and QUICKI were the independent variables, only fasting TGs significantly predicted the AUC (coefficient B=11.866, p=0.008).

CONCLUSIONS

The fasting TG concentration is the main determinant of postprandial lipaemia. The obesity state was not an additional determinant for exaggerated postprandial response in MetS women. The abnormal postprandial lipaemia could be added as an important metabolic disturbance to the MetS.

Endothelial dysfunction induced by postprandial lipemia is neutralized by addition of proteins to the fatty meal

BACKGROUND

Postprandial lipemia is known to reduce endothelium-dependent flow-mediated vasodilation (FMD). Because postprandial lipemia can be acutely mitigated when proteins are added to the fatty meal, we investigated whether this mitigation could neutralize the lipemia-induced endothelial dysfunction.

DESIGN

Sixteen healthy students (aged 19-23, eight males and eight females) received three different test meals at intervals of 1 week between successive tests. Each meal contained whipping cream alone or whipping cream together with either caseinate or soy protein. The whipping cream contained 33% fat, and 3 ml (= 1 g fat) was given per kg body weight. The proteins added were either 50 g sodium caseinate or 50 g soy protein. FMD was assessed by two-dimensional ultrasonography of the brachial artery in the fasting state and 1, 2, 3, 4, 5, 6, 7, and 8h after the fatty meal. Blood was withdrawn at the same time-points from the other arm. Triglycerides, free fatty acids, and insulin were determined using routine methods, and both L-arginine and asymmetric dimethylarginine (ADMA) were determined by LC-MS.

RESULTS

Postprandial lipemia reduced FMD, the reduction reaching a maximum of 58% after 3 h. This impairment of endothelial function was not observed when either of the test proteins had been added to the fatty meal (p < 0.01 for caseinate and p < 0.001 for soy protein). The effects of the protein addition were decreases in triglycerides and free fatty acids, increased insulin concentrations at all time-points, and an increased arginine/ADMA ratio between 1 and 5h after the meal, particularly in the case of the soy protein.

CONCLUSION

We suggest that the neutralization of the lipemia-induced endothelial dysfunction is caused by direct and indirect effects of the proteins insulinotropy and, secondly, by an increased supply of L-arginine.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.

Inflammatory Markers and the Metabolic Syndrome

Inflammation in the vasculature might be an important pathogenic link between cardiovascular diseases and the metabolic syndrome. Inflammation can be reduced by a variety of approaches including diet, exercise, cardiovascular drugs, and insulin sensitizers. Importantly, these different measures improve vascular function and reduce inflammation by distinct mechanisms. Therefore, combination therapy including lifestyle modifications and multiple drugs from separate classes might produce additive beneficial outcomes. We review plausible mechanisms for effects of combination therapy to reduce inflammation, improve endothelial dysfunction, and decrease insulin resistance in atherosclerosis, coronary heart disease, and hypertension in the context of insulin-resistant states including diabetes, obesity, and the metabolic syndrome.

Beneficial vascular and metabolic effects of peroxisome proliferator-activated receptor-alpha activators

Fibric acid is a synthetic ligand of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-alpha that is highly expressed in skeletal muscle and heart, where it promotes beta-oxidation of fatty acids to mediate hypolipidemic actions. PPAR-alpha regulates expression of key proteins involved in atherogenesis, vascular inflammation, plaque instability, and thrombosis. Thus, PPAR-alpha may exert direct antiatherogenic actions in the vascular wall. Endothelial dysfunction associated with the metabolic syndrome and other insulin-resistant states is characterized by impaired insulin-stimulated nitric oxide production from the endothelium and decreased blood flow to skeletal muscle. Thus, improvement in insulin sensitivity leads to improved endothelial function. This may be an additional mechanism whereby fibrates decrease the incidence of coronary heart disease. Adiponectin is a protein secreted specifically by adipose cells that may couple regulation of insulin sensitivity with energy metabolism and serve to link obesity with insulin resistance. In this review, we discuss the mechanisms underlying the vascular and metabolic effects of fibrates that may act synergistically to prevent or regress atherosclerosis and coronary heart disease.

Dysregulated arginine metabolism, hemolysis-associated pulmonary hypertension, and mortality in sickle cell disease

CONTEXT

Sickle cell disease is characterized by a state of nitric oxide resistance and limited bioavailability of l-arginine, the substrate for nitric oxide synthesis. We hypothesized that increased arginase activity and dysregulated arginine metabolism contribute to endothelial dysfunction, pulmonary hypertension, and patient outcomes.

OBJECTIVE

To explore the role of arginase in sickle cell disease pathogenesis, pulmonary hypertension, and mortality.

DESIGN

Plasma amino acid levels, plasma and erythrocyte arginase activities, and pulmonary hypertension status as measured by Doppler echocardiogram were prospectively obtained in outpatients with sickle cell disease. Patients were followed up for survival up to 49 months.

SETTING

Urban tertiary care center and community clinics in the United States between February 2001 and March 2005.

PARTICIPANTS

Two hundred twenty-eight patients with sickle cell disease, aged 18 to 74 years, and 36 control participants.

MAIN OUTCOME MEASURES

Plasma amino acid levels, plasma and erythrocyte arginase activities, diagnosis of pulmonary hypertension, and mortality.

RESULTS

Plasma arginase activity was significantly elevated in patients with sickle cell disease, with highest activity found in patients with secondary pulmonary hypertension. Arginase activity correlated with the arginine-ornithine ratio, and lower ratios were associated with greater severity of pulmonary hypertension and with mortality in this population (risk ratio, 2.5; 95% confidence interval [CI], 1.2-5.2; P = .006). Global arginine bioavailability, characterized by the ratio of arginine to ornithine plus citrulline, was also strongly associated with mortality (risk ratio, 3.6; 95% CI, 1.5-8.3; P<.001). Increased plasma arginase activity was correlated with increased intravascular hemolytic rate and, to a lesser extent, with markers of inflammation and soluble adhesion molecule levels.

CONCLUSIONS

These data support a novel mechanism of disease in which hemolysis contributes to reduced nitric oxide bioavailability and endothelial dysfunction via release of erythrocyte arginase, which limits arginine bioavailability, and release of erythrocyte hemoglobin, which scavenges nitric oxide. The ratios of arginine to ornithine and arginine to ornithine plus citrulline are independently associated with pulmonary hypertension and increased mortality in patients with sickle cell disease.

Beneficial effects of fenofibrate to improve endothelial dysfunction and raise adiponectin levels in patients with primary hypertriglyceridemia

OBJECTIVE

Improvement in endothelial function is predicted to improve insulin sensitivity, and this may be one mechanism by which fenofibrate decreases the incidence of coronary heart disease. We hypothesize fenofibrate improves endothelial function by enhancing insulin sensitivity.

RESEARCH DESIGN AND METHODS

We administered placebo or fenofibrate 200 mg daily for 8 weeks to 46 patients with primary hypertriglyceridemia (24 had metabolic syndrome). This study was randomized, double blind, placebo controlled, and crossover in design.

RESULTS

Compared with placebo, fenofibrate decreased total cholesterol, non-HDL cholesterol, apolipoprotein B, and triglycerides and increased HDL cholesterol and apolipoprotein A-I (all P < 0.001) while tending to decrease LDL cholesterol (P = 0.069). Fenofibrate significantly improved percent flow-mediated dilator response to hyperemia by 48 +/- 5% (P < 0.001) and lowered plasma levels of high-sensitivity C-reactive protein (hsCRP) relative to baseline measurements from 0.80 to 0.70 mg/l (P = 0.001) and fibrinogen levels by 16 +/- 3% (P < 0.001). Compared with placebo, fenofibrate therapy significantly increased plasma levels of adiponectin by 14 +/- 5% (P = 0.008) and increased insulin sensitivity (assessed by quantitative insulin sensitivity check index [QUICKI]) by 6 +/- 2% (P = 0.048). There were significant correlations between percent changes in adiponectin levels and percent changes in flow-mediated dilation (r = 0.401, P = 0.006), hsCRP (r = -0.443, P = 0.002), or QUICKI (r = 0.292, P = 0.049). Multivariate regression analysis showed that only changes in adiponectin levels persisted as an independent predictor of changes in flow-mediated dilation (r = 0.504, P = 0.013). Overall, we observed similar results in 24 patients with metabolic syndrome.

CONCLUSIONS

Fenofibrate therapy significantly improved percent flow-mediated dilator response to hyperemia, reduced inflammation marker levels, increased adiponectin levels, and improved insulin sensitivity in hypertriglyceridemic or metabolic syndrome patients.