Effects of LDL cholesterol on vascular function

Exploring the effects of feeding methods on the growth and meat flavor of Wenchang chicken

Wenchang chicken, renowned for its high-quality meat, is the economic meat breed in Hainan Province, China. This study compared cage-rearing (CR) and free-range (FR) groups in terms of growth performance, slaughter performance, meat quality, IMP (inosine monophosphate) content, AAs, FAs, serum lipid metabolites, and transcriptomic and metabolomic analyses. The CR group showed increased body weight, live weight, and abdominal fat but lower leg muscle percentage and breast muscle redness, suggesting flavor differences. CR chickens had higher IMP, threonine (Thr), and pentadecanoic, oleic, and linoleic acids, while glutamate (Glu) and alpha-linolenic acid were lower compared to FR. Glycine was elevated, but histidine, myristic, and tricosanoic acids were lower in CR leg muscle. Serum analysis revealed higher total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), fatty acid synthase (FAS), thyroid-stimulating hormone (TSH), leptin (LEP), and adiponectin (ADP) in the CR group. Transcriptomic and metabolomic studies identified 252 differentially expressed genes and 34 metabolites linked to metabolic pathways. In summary, CR system can improve production performance, FR system is considered more flavorful. The results can act as a theoretical basis for selecting a suitable rearing method for this unique breed.

A Systematic Review of Endothelial Dysfunction in Chronic Venous Disease-Inflammation, Oxidative Stress, and Shear Stress

Chronic venous disease (CVD) is among the most common diseases in industrialized countries and has a significant socioeconomic impact. The diversity of clinical symptoms and manifestations of CVD pose major challenges in routine diagnosis and treatment. Despite the high prevalence and the huge number of venous surgical interventions performed every day, a substantial proportion of the etiopathogenesis remains unclear. There are several widely advocated and generally valid theories of "peri-capillary fibrin cuffs" and "white cell trapping hypothesis", which consider the role of venous reflux/obstruction, inflammation, vascular remodeling, hemodynamic changes, genetic and social risk factors. There are several specific provoking factors for the development of venous reflux: incompetence of the valve system, inflammation of the vascular wall, and venous hypertension. Over the past few years, increasing scientific data has demonstrated the link between oxidative stress, endothelial dysfunction, and vascular inflammation. High levels of oxidants and persistent inflammation can cause cumulative changes in hemodynamics, resulting in permanent and irreversible damage to the microcirculation and endothelial cells. Production of reactive oxygen species and expression of inflammatory cytokines and adhesion molecules are involved in a vicious cycle of venous wall remodeling. The interaction of ROS, and in particular, the superoxide anion radical, with nitric oxide leads to a decrease in NO bioavailability, followed by the initiation of prolonged vasoconstriction and hypoxia and impairment of vascular tone. This review addresses the role of ED, oxidative, and hemodynamic stress in the CVD mediation. Based on predefined inclusion and exclusion criteria, we conducted a systematic review of published scientific articles using PubMed, PMC Europe, Scopus, WoS, MEDLINE, and Google Scholar databases in the interval from 24 April 2002 to 1 April 2025. The current review included studies (n = 197) scientific articles, including new reviews, updates, and grey literature, which were evaluated according to eligibility criteria. The selection process was performed using a standardized form according to PRISMA rules, the manual search of the databases, and a double-check to ensure transparent and complete reporting of reviews. Studies had to report quantitative assessments of the relationship between vascular endothelial dysfunction, inflammation, oxidative stress, and shear stress in a chronic venous disease.

Assessment of Vascular Function in Response to High-Fat and Low-Fat Ground Beef Consumption in Men

Red meat is stigmatized as an unhealthy protein choice; however, its impacts on vascular function have not been evaluated. We aimed to measure the vascular impact of adding either low-fat (~5% fat) ground beef (LFB) or high-fat (~25% fat) ground beef (HFB) to a habitual diet in free-living men. Twenty-three males (39.9 ± 10.8 years, 177.5 ± 6.7 cm, 97.3 ± 25.0 kg) participated in this double-blind crossover study. Assessment of vascular function and aerobic capacity were measured at entry and in the last week of each intervention and washout period. Participants then completed two 5-week dietary interventions (LFB or HFB; 5 patties/week) in a randomized order with a 4-week washout. Data were analyzed via 2 × 2 repeated-measures ANOVA (p < 0.05). The HFB intervention improved FMD relative to all other time points, while lowering systolic (SBP) and diastolic blood pressure (DBP) relative to entry. Neither the HFB nor the LFB altered pulse wave velocity. The addition of either low- or high-fat ground beef did not negatively alter vascular function. In fact, consuming HFB improved FMD and BP values, which may be mediated by lowering LDL-C concentrations.

Effects of NAC assisted insulin on cholesterol metabolism disorders in canine type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is a metabolic disease characterized by insulin deficiency and often accompanied by hypercholesterolemia. NAC is an effective antioxidative drug, but its application in the treatment of diabetes is still rare. A total of forty beagles were randomly divided into five groups: control group, DM group, INS group, INS with NAC group, and NAC group. The experiment lasted for 120 days. Results revealed that biochemical criterion increased in the DM group, while the indicators significantly decreased on the INS combined with NAC treatment group. Moreover, the insulin released test demonstrated that the model of T1DM was successfully constructed. The result of B ultrasound of gallbladder showed remarkable cholestasis in DM group. The cholesterol metabolism-related enzyme activity (HMGCR and SQLE) was evidently increased in DM group, but decreased in INS and NAC group. The content of TG, LDL-c, and HDL-c in liver was detected by the kit, and it was found that the content of TG, LDL-c, and HDL-c in DM group were reduced. Histopathological observation revealed that the cholestasis of liver cells and hepatic cords were disordered in DM group, the symptoms were alleviated under INS and NAC treatment. Additionally, the protein and mRNA expression of HMGCR and LDLR were obviously increased in DM group, but down regulated in INS and NAC treatment group. Overall, the liver function injury and secondary hypercholesterolemia can be found in T1DM canines, and NAC can relieve cholesterol metabolism disorder in the treatment of canine T1DM.

Severe COVID-19-A Review of Suggested Mechanisms Based on the Role of Extracellular Matrix Stiffness

The severity of COVID-19 commonly depends on age-related tissue stiffness. The aim was to review publications that explain the effect of microenvironmental extracellular matrix stiffness on cellular processes. Platelets and endothelial cells are mechanosensitive. Increased tissue stiffness can trigger cytokine storm with the upregulated expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha and interleukin IL-6, and tissue integrity disruption, leading to enhanced virus entry and disease severity. Increased tissue stiffness in critically ill COVID-19 patients triggers platelet activation and initiates plague formation and thrombosis development. Cholesterol content in cell membrane increases with aging and further enhances tissue stiffness. Membrane cholesterol depletion decreases virus entry to host cells. Membrane cholesterol lowering drugs, such as statins or novel chitosan derivatives, have to be further developed for application in COVID-19 treatment. Statins are also known to decrease arterial stiffness mitigating cardiovascular diseases. Sulfated chitosan derivatives can be further developed for potential use in future as anticoagulants in prevention of severe COVID-19. Anti-TNF-α therapies as well as destiffening therapies have been suggested to combat severe COVID-19. The inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells pathway must be considered as a therapeutic target in the treatment of severe COVID-19 patients. The activation of mechanosensitive platelets by higher matrix stiffness increases their adhesion and the risk of thrombus formation, thus enhancing the severity of COVID-19.

A High Cholesterol Diet During Late Pregnancy Impairs Long-Term Maternal Vascular Function in Mice

BACKGROUND

Gestational dyslipidemia is associated with pregnancy complications including preeclampsia. However, whether gestational dyslipidemia leads postpartum vascular dysfunction, which could increase the risk for cardiovascular complications later in life, is not known. Here, we aimed to determine whether a gestational dyslipidemia affects postpartum vascular health and induces early signs of atherosclerosis.

METHODS

Pregnant C57BL/6 mice received a high cholesterol diet or control diet from gestational day 13.5 until term. After delivery, all mice received the control diet for ≈3 months postpartum (PP). Age-matched nulliparous females were on the same diets for equal periods. After 3 months, all mice were euthanized, serum was collected, and aortas were isolated to assess vascular function (wire myography) and markers of oxidative stress and early atherosclerosis.

RESULTS

PP-high cholesterol diet females had increased circulating cholesterol levels compared with PP-control diet mice, without effect of the diet in nulliparous mice. Methacholine-induced vasodilation was impaired, and nitric oxide contribution reduced, by the high cholesterol diet in aortas of PP mice, but not in nulliparous mice. Exposure to oxidized low-density-protein cholesterol further impaired methylcholine-induced vasodilation in PP-high cholesterol diet aortas only. Compared with PP-control diet mice, aortic inducible nitric oxide synthase expression, reactive oxygen species and nitrotyrosine levels were increased in aortas from PP-high cholesterol diet mice. No differences in aortic lipid deposition and macrophage infiltration were found.

CONCLUSIONS

Exposure to a high cholesterol diet in pregnancy impairs vascular function postpartum. Our results support the hypothesis that gestational dyslipidemia impacts maternal vascular function after pregnancy, which could potentially predispose these women to future cardiovascular complications.

The significances and clinical implications of cholesterol components in human breast cancer

Breast cancer is one the most common malignancies and leading cause of cancer-related mortality in women. Recent studies suggested that hypercholesterolemia may be the potential modifiable risk factors for breast cancer. Cholesterol was well-known for its strong association with cardiovascular disease for long. Moreover, solid evidence has been provided by different studies to illustrate the correlation between lipid and incidence in multiple cancers. Although the conclusion remains controversial or sometimes contrary, which may be due to the multifactorial nature of the disease and the disparity of ethnic population, it is critical to elucidate the relationship between specific cholesterol components in certain population and the exact underlying mechanism of the lipid-associated signaling pathway in breast cancer. The implications of dysregulated lipoproteins as therapeutic targets or options for breast cancer provide novel strategies for us in combating with this malignant disease, which may be achieved by manipulating lipid levels with pharmacological compounds.

Caffeic Acid Protects against Iron-Induced Cardiotoxicity by Suppressing Angiotensin-Converting Enzyme Activity and Modulating Lipid Spectrum, Gluconeogenesis and Nucleotide Hydrolyzing Enzyme Activities

The protective effects of caffeic acid on angiotensin-converting enzyme (ACE) and purinergic enzyme activities, as well as gluconeogenesis was investigated in iron-induced cardiotoxicity. Cardiotoxicity was induced in heart tissues harvested from healthy male SD rats by 0.1 mM FeSO4. Treatment was carried out by co-incubating hearts tissues with caffeic acid and 0.1 mM FeSO4. Cardiotoxicity induction significantly (p < 0.05) depleted GSH level, SOD, catalase, and ENTPDase activities, with concomitant elevation of the levels of malondialdehyde (MDA), nitric oxide, ACE, ATPase, glycogen phosphorylase, glucose 6-phosphatase, fructose 6-biphsophatase, and lipase activities. There was significant (p < 0.05) reversion in these levels and activities on treatment with caffeic acid. Caffeic acid also caused depletion in cardiac levels of cholesterol, triglyceride, LDL-c, while elevating HDL-c level. Our results suggest the protective effect of caffeic acid against iron-mediated cardiotoxicity as indicated by its ability to suppress oxidative imbalance and ACE activity, while concomitantly modulating nucleotide hydrolysis and metabolic switch.

Strawberry fruit (Fragaria x ananassa cv. Romina) extenuates iron-induced cardiac oxidative injury via effects on redox balance, angiotensin-converting enzyme, purinergic activities, and metabolic pathways

The potential cardioprotective properties of strawberry fruit (Fragaria x ananassa) (SF) were investigated in cardiac tissues ex vivo. Oxidative injury was induced by incubating freshly harvested cardiac tissue homogenates from healthy Sprague Dawley male rats with 0.1 mM FeSO₄ for 30 min at 37°C. The induction of oxidative injury resulted in depleted levels of glutathione, superoxide dismutase, catalase, E-NTPDase activities, and HDL-c, while elevating the levels of malondialdehyde, angiotensin-converting enzyme, acetylcholinesterase, ATPase, lipase activities, cholesterol, triglyceride, and LDL-c. Co-incubation with SF significantly reversed these levels and activities with concomitant depletion of oxidative-induced metabolites and reactivation of oxidative-inactivated pathways, while limiting beta-oxidation of very long chain fatty acids and mitochondrial beta-oxidation of medium-chain saturated fatty acids pathways. These data portray the potential cardioprotective effects of strawberry fruits against oxidative-induced cardiopathy via the attenuation of oxidative stress, inhibition of ACE and acetylcholinesterase activities, and modulation of lipid dysmetabolism. PRACTICAL APPLICATIONS: Fruits and other fruit-based products have been enjoying wide acceptability among consumers due to their immense medicinal benefits particularly, on cardiovascular health. Strawberries are among the common fruits in the world. Over the years, cardiovascular diseases have been known to contribute greatly to global mortality irrespective of age. This study reports the potentials of strawberry fruits to protect against oxidative mediated cardiovascular dysfunctions. Thus, the fruits can be utilized as a cheap alternative for the development of nutraceuticals for maintaining cardiac health.

Benefits of physical exercise on cognition and glial white matter pathology in a mouse model of vascular cognitive impairment and dementia

White matter (WM) pathology is a clinically predictive feature of vascular cognitive impairment and dementia (VCID). Mice overexpressing transforming growth factor-β1 (TGF) with an underlying cerebrovascular pathology when fed a high cholesterol diet (HCD) develop cognitive deficits (VCID mice) that we recently found could be prevented by physical exercise (EX). Here, we further investigated cognitive and WM pathology in VCID mice and examined the cellular substrates of the protective effects of moderate aerobic EX focusing on WM alterations. Six groups were studied: Wild-type (WT) and TGF mice (n = 20-24/group) fed standard lab chow or a 2% HCD, with two HCD-fed groups given concurrent access to running wheels. HCD had a significant negative effect in TGF mice that was prevented by EX on working and object recognition memory, the latter also altered in WT HCD mice. Whisker-evoked increases in cerebral blood flow (CBF) were reduced in HCD-fed mice, deficits that were countered by EX, and baseline WM CBF was similarly affected. VCID mice displayed WM functional deficits characterized by lower compound action potential amplitude not found in EX groups. Moreover, there was an increased number of collapsing capillaries, galectin-3-expressing microglial cells, as well as a reduced number of oligodendrocytes in the WM of VCID mice; all of which were prevented by EX. Our findings indicate that a compromised cerebral circulation precedes reduced WM vascularization, enhanced WM inflammation and impaired oligodendrogenesis that all likely account for the increased susceptibility to memory impairments in VCID mice, which can be prevented by EX. MAIN POINTS: A compromised cerebral circulation increases susceptibility to anatomical and functional white matter changes that develop alongside cognitive deficits when challenged with a high cholesterol diet; preventable by a translational regimen of exercise.

Buddleja saligna Willd (Loganiaceae) inhibits angiotensin-converting enzyme activity in oxidative cardiopathy with concomitant modulation of nucleotide hydrolyzing enzymatic activities and dysregulated lipid metabolic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Buddleja saligna Willd (Loganiaceae), mostly indigenous to South Africa is traditionally used in the treatment cardio-dysfunctional related ailments amongst other diseases.

AIMS

The cardio-protective effect of B. saligna was investigated in ferric-induced oxidative cardiopathy.

METHODS

Hearts harvested from healthy male SD rats were incubated with 0.1 mM FeSO₄ to induce oxidative damage and co-incubated with B. saligna extract. Reaction mixtures without the extract served as negative control, while tissues without the extract or standard antioxidant (gallic acid) and pro-oxidant served as the normal control. The tissues were analyzed for levels of glutathione, malondialdehyde, and nitric oxide as well as cholinergic, angiotensin-converting enzyme (ACE), lipase, and purinergic enzymes activities, lipid profiles, fatty acid metabolic pathways and metabolites.

RESULTS

Induction of oxidative damage significantly (p < 0.05) depleted the levels of GSH, SOD, catalase, and ENTPDase activities, while concomitantly elevating the levels of MDA, NO, ACE, acetylcholinesterase, lipase and ATPase activities. These levels and activities were significantly reversed on treatment with B. saligna. Treatment with B. saligna also led to depletion of cardiac cholesterol and LDL-c levels, while elevating triglyceride and HDL-c level. It also depleted oxidative-induced lipid metabolites with concomitant generation of thirteen other metabolites. B. saligna also inactivated oxidative-induced pathways for beta oxidation of very long chain fatty acids, glycerolipid metabolism, and fatty acid elongation in mitochondria.

CONCLUSION

These results suggest that B. saligna protects against ferric-induced oxidative cardiopathy by mitigating oxidative stress, while concomitantly inhibiting ACE, acetylcholinesterase and lipase activities, and modulating lipid spectrum and dysregulated metabolic pathways.

LDL cholesterol is associated with systemic vascular resistance and wave reflection in subjects naive to cardiovascular drugs

BACKGROUND AND AIM

Low density lipoprotein cholesterol (LDL-C) is a primary risk factor for atherosclerosis, but it is also associated with elevated blood pressure (BP) and future development of hypertension. We examined the relationship between LDL-C and haemodynamic variables in normotensive and never-treated hypertensive subjects.

METHODS

We recruited 615 volunteers (19-72 years) without lipid-lowering and BP-lowering medication. Supine haemodynamics were recorded using continuous radial pulse wave analysis, whole-body impedance cardiography, and single channel electrocardiogram. The haemodynamic relations of LDL-C were examined using linear regression analyses with age, sex, body mass index (BMI) (or height and weight as appropriate), smoking status, alcohol use, and plasma C-reactive protein, sodium, uric acid, high density lipoprotein cholesterol (HDL-C), triglycerides, estimated glomerular filtration rate, and quantitative insulin sensitivity check index as the other included variables.

RESULTS

The mean (SD) characteristics of the subjects were: age 45 (12) years, BMI 27 (4) kg/m², office BP 141/89 (21/13) mmHg, creatinine 74 (14) µmol/l, total cholesterol 5.2 (1.0), LDL-C 3.1 (0.6), triglycerides 1.2 (0.8), and HDL-C 1.6 (0.4) mmol/l. LDL-C was an independent explanatory factor for aortic systolic and diastolic BP, augmentation index, pulse wave velocity (PWV), and systemic vascular resistance index (p < 0.05 for all). When central BP was included in the model for PWV, LDL-C was no longer an explanatory factor for PWV.

CONCLUSIONS

LDL-C is independently associated with BP via systemic vascular resistance and wave reflection. These results suggest that LDL-C may play a role in the pathogenesis of primary hypertension.

Acute Hyperglycemia Impairs Vascular Function in Healthy and Cardiometabolic Diseased Subjects

Objectives—

Controversy exists over the effect of acute hyperglycemia on vascular function. In this systematic review, we compared the effect of acute hyperglycemia on endothelial and vascular smooth muscle functions across healthy and cardiometabolic diseased subjects.

Approach and Results—

A systematic search of MEDLINE, EMBASE, and Web of Science from inception until July 2014 identified articles evaluating endothelial or vascular smooth muscle function during acute hyperglycemia and normoglycemia. Meta-analyses compared the standardized mean difference (SMD) in endothelial and vascular smooth muscle functions between acute hyperglycemia and normoglycemia. Subgroup analyses and metaregression identified sources of heterogeneity. Thirty-nine articles (525 healthy and 540 cardiometabolic subjects) were analyzed. Endothelial function was decreased (39 studies; n=1065; SMD, −1.25; 95% confidence interval, −1.52 to −0.98; P <0.01), whereas vascular smooth muscle function was preserved (6 studies; n=144; SMD, −0.07; 95% confidence interval, −0.30 to 0.16; P =0.55) during acute hyperglycemia compared with normoglycemia. Significant heterogeneity was detected among endothelial function studies ( P <0.01). A subgroup analysis revealed that endothelial function was decreased in the macrocirculation (30 studies; n=884; SMD, −1.40; 95% confidence interval, −1.68 to −1.12; P <0.01) but not in the microcirculation (9 studies; n=181; SMD, −0.63; 95% confidence interval, −1.36 to 0.11; P =0.09). Similar results were observed according to health status. Macrovascular endothelial function was inversely associated with age, blood pressure, and low-density lipoprotein cholesterol and was positively associated with the postocclusion interval of vascular assessment.

Conclusions—

To our knowledge, this is the first systematic review and meta-analysis of its kind. In healthy and diseased subjects, we found evidence for macrovascular but not microvascular endothelial dysfunction during acute hyperglycemia.

Systemic circulatory influences on retinal microvascular function in middle-age individuals with low to moderate cardiovascular risk

PURPOSE

To investigate the relationship between retinal microvascular reactivity, circulatory markers for CVD risk and systemic antioxidative defence capacity in healthy middle-aged individuals with low to moderate risk of CVD.

METHODS

Retinal vascular reactivity to flickering light was assessed in 102 healthy participants (46-60 years) by means of dynamic retinal vessel analysis (DVA). Other vascular assessments included carotid intima-media thickness (C-IMT) and blood pressure (BP) measurements. Total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and blood glutathione levels in its reduced (GSH) and oxidized (GSSG) forms were also determined for each participant, along with Framingham risk scores (FRS).

RESULTS

Retinal arterial baseline diameter fluctuation (BDF) was independently, significantly and negatively influenced by LDL-C levels (β = -0.53, p = 0.027). Moreover, the arterial dilation slope (SlopeAD ) was independently, significantly and positively associated with redox index (GSH: GSSG ratio, β = 0.28, p = 0.016), while the arterial constriction slope (SlopeAC ) was significantly and negatively influenced by blood GSH levels (β = -0.20, p = 0.042), and positively associated with FRS (β = 0.25, p = 0.009). Venous BDF and dilation amplitude (DA) were also negatively influenced by plasma LDL-C levels (β = -0.83, p = 0.013; and β = -0.22, p = 0.028, respectively).

CONCLUSIONS

In otherwise healthy individuals with low to moderate cardiovascular risk, retinal microvascular dilation and constriction responses to stress levels are influenced by systemic antioxidant capacity, and circulating markers for cardiovascular risk.

[The age-related macular degeneration as a vascular disease/part of systemic vasculopathy: contributions to its pathogenesis]

The wall of blood vessels including those in choroids may be harmed by several repeated and/or prolonged mechanical, physical, chemical, microbiological, immunologic, and genetic impacts (risk factors), which may trigger a protracted response, the so-called host defense response. As a consequence, pathological changes resulting in vascular injury (e. g. atherosclerosis, age-related macular degeneration) may be evolved. Risk factors can also act directly on the endothelium through an increased production of reactive oxygen species promoting an endothelial activation, which leads to endothelial dysfunction, the onset of vascular disease. Thus, endothelial dysfunction is a link between the harmful stimulus and vascular injury; any kind of harmful stimuli may trigger the defensive chain that results in inflammation that may lead to vascular injury. It has been shown that even early age-related macular degeneration is associated with the presence of diffuse arterial disease and patients with early age-related macular degeneration demonstrate signs of systemic and retinal vascular alterations. Chronic inflammation, a feature of AMD, is tightly linked to diseases associated with ED: AMD is accompanied by a general inflammatory response, in the form of complement system activation, similar to that observed in degenerative vascular diseases such as atherosclerosis. All these facts indicate that age-related macular degeneration may be a vascular disease (or part of a systemic vasculopathy). This recognition could have therapeutic implications because restoration of endothelial dysfunction may prevent the development or improve vascular disease resulting in prevention or improvement of age-related macular degeneration as well.

Dimethylarginine dimethylaminohydrolase regulation: a novel therapeutic target in cardiovascular disease

Asymmetric dimethylarginine (ADMA), an endogenous methylated form of the amino acid L-arginine, inhibits the activity of the enzyme endothelial nitric oxide synthase, with consequent reduced synthesis of nitric oxide. ADMA is metabolised to L-citrulline and dimethylamine by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). The modulation of DDAH activity and expression plays a pivotal role in regulating intracellular ADMA concentrations, with important effects on vascular homeostasis. For example, impairment in DDAH activity, resulting in elevated ADMA concentrations and reduced nitric oxide synthesis, can promote the onset and progression of atherosclerosis in experimental models. This review discusses the current role of ADMA and DDAH in vascular health and disease, the techniques used to assess DDAH activity and expression, and the results of recent studies on pharmacological and biological agents modulating DDAH activity and expression. Suggestions for future basic and clinical research directions are also discussed.

Soluble CD36 and risk markers of insulin resistance and atherosclerosis are elevated in polycystic ovary syndrome and significantly reduced during pioglitazone treatment

OBJECTIVE

We investigated the relation between soluble CD36 (sCD36), risk markers of atherosclerosis and body composition, and glucose and lipid metabolism in polycystic ovary syndrome (PCOS).

RESEARCH DESIGN AND METHODS

Thirty PCOS patients were randomized to 30 mg/day pioglitazone or placebo for 16 weeks. Fourteen weight-matched healthy female subjects were included as control subjects. sCD36, oxidized LDL (oxLDL), high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, euglycemic-hyperinsulinemic clamps, and whole-body dual-energy X-ray absorptiometry scans were performed.

RESULTS

sCD36 (2.87 relative units [0.88-9.36] vs. 1.67 relative units [0.72-3.89]), oxLDL (44.9 units/l [26.9-75.1] vs. 36.1 units/l [23.4-55.5]), and hsCRP (0.26 mg/dl [0.03-2.41] vs. 0.12 mg/dl [0.02-0.81]) were significantly increased in PCOS patients versus control subjects (geometric mean +/- 2 SD). In PCOS, positive correlations were found between central fat mass and sCD36 (r = 0.43), hsCRP (r = 0.43), and IL-6 (r = 0.42) (all P < 0.05). After adjusting for fat mass, sCD36 and oxLDL correlated inversely with measures of insulin-stimulated glucose metabolism and positively with lipid oxidation during insulin stimulation in PCOS patients and control subjects (n = 44). sCD36 and oxLDL were significant independent predictors of glucose and lipid metabolism, whereas hsCRP and IL-6 showed no significant contribution. Following pioglitazone treatment, insulin sensitivity increased, whereas sCD36 (3.21 relative units [0.76-13.6] vs. 2.33 relative units [0.84-6.46]) and hsCRP decreased (P < 0.05). No significant changes were measured in body composition.

CONCLUSIONS

sCD36 and oxLDL correlated with measures of insulin sensitivity independent of central fat mass. Pioglitazone treatment reduced sCD36 while improving insulin-stimulated glucose metabolism, further supporting the association between sCD36 and insulin resistance in PCOS.

Thiazolidinediones-improving endothelial function and potential long-term benefits on cardiovascular disease in subjects with type 2 diabetes

Endothelial dysfunction, which leads to impaired vasodilation, is an early event in the development of atherosclerosis. A number of mechanisms involving, for example, cell adhesion molecules, chemokines, and cytokines, contribute to this inflammatory disease, and insulin resistance plays a cardinal role in accelerating these processes. Hyperglycemia and other metabolic abnormalities that are commonly associated with insulin resistance also contribute to impaired endothelial function. In addition, the important role of the endothelium in damage repair following a cardiovascular event is emerging. The combination of proatherogenic factors in patients with type 2 diabetes results in blunted endothelial function and an increased risk of cardiovascular disease. Insulin-sensitizing agents such as thiazolidinediones have demonstrated a number of clinical benefits, including anti-inflammatory and antithrombotic properties, which may impact on the course of atherosclerosis. Recent studies have demonstrated that thiazolidinediones improve endothelial function in subjects with and without type 2 diabetes.

Beyond lipid lowering: the anti-hypertensive role of statins

INTRODUCTION

The management of the hypercholesterolemic patient has evolved tremendously with the introduction of the HMG-CoA Reductase inhibitors, a class of drugs better known as the statins. Statins modify cholesterol metabolism by inhibiting the rate-limiting enzyme of cholesterol biosynthesis, producing greater decreases in plasma cholesterol levels than previously realized with hypolipidemic therapy. With the advent of the classic statin-megatrials such as the Scandinavian Simvastatin Survival Study (4S), WOSCOPS, CARE, and the more recent Heart Protection Study (HPS), the role of statins in both the primary and secondary prevention and ultimate risk reduction of patients with coronary disease has been firmly established.

DISCUSSION

With an increase in use and popularity, a number of beneficial actions of the statins unrelated to their cholesterol-lowering ability have been reported. These effects have generated greater interest in the possible additional roles and indications for the use of these drugs. Of central focus in this paper is the cholesterol-independent benefit of this group of agents on the cardiovascular system, particularly on the lowering of systemic blood pressure. A number of hypotheses have been proposed for this action and these shall be reviewed within this paper.

CONCLUSION

We explore recent data that suggests that statins may provide substantial reduction of blood pressure in the hypertensive, hypercholesterolemic patient independent of their lipid-lowering effect. In addition, we review several notable publications that postulate unique mechanisms for this action and benefit. We also present plausible explanations as to why some of the larger statin trials did not report similar such findings.

Effects of rosiglitazone on endothelial function in men with coronary artery disease without diabetes mellitus

Recent data have shown that peroxisome proliferator-activated receptor-gamma agonists may exert protective effects on the vascular endothelium by amelioration of insulin resistance and through direct anti-inflammatory effects. In this study we assessed the effect of rosiglitazone on biochemical and biophysical indexes of endothelial function in male, nondiabetic patients with coronary artery disease. Consecutive male subjects (n = 71) with clinically stable, angiographically documented coronary artery disease and without diabetes mellitus were investigated. Patients were randomized in a double-blind manner to placebo or rosiglitazone for a total of 24 weeks. Flow-mediated dilation (FMD) of the brachial artery, C-reactive protein, von Willebrand factor, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels, and parameters of glucose and lipid metabolism were measured at baseline and after 12 and 24 weeks of treatment. Rosiglitazone treatment significantly reduced C-reactive protein (median 0.56 mg/L [interquartile range 0.33 to 1.02] to 0.33 mg/L [interquartile range 0.26 to 0.40], p <0.01), von Willebrand factor (139 +/- 47 to 132 +/- 44 IU/dl, p = 0.02), insulin resistance index (p = 0.05), and mean low-density lipoprotein (LDL) density (p <0.001) compared with placebo. However, no significant differences were seen between the rosiglitazone and placebo groups with regard to brachial artery FMD, intercellular adhesion molecule-1, or vascular cell adhesion molecule-1 levels. Rosiglitazone treatment significantly increased LDL (2.62 +/- 0.72 to 2.95 +/- 0.84 mmol/L, p = 0.03) and triglyceride (1.23 +/- 0.63 to 1.56 +/- 0.98 mmol/L, p = 0.04) levels. Thus, rosiglitazone reduced markers of inflammation and endothelial activation, but this did not translate into an improvement in FMD. Increased LDL and triglyceride levels may have played a role.