Endothelial function varies according to insulin resistance disease type

The Role of Serum Free Fatty Acids in Endothelium-Dependent Microvascular Function

BACKGROUND

Elevated serum free fatty acid (FFA) concentration is associated with insulin resistance and is a hallmark of metabolic syndrome. A pathological feature of insulin resistance is impaired endothelial function.

OBJECTIVE

To investigate the effect of FFA reduction with either acipimox, a nicotinic acid derivative that impairs lipolysis, or salsalate, a salicylate that reduces basal and inflammation-induced lipolysis, on insulin-mediated endothelium-dependent vasodilation.

METHODS

This was a post hoc, combined analysis of two randomised, double-blind, placebo-controlled crossover trials. Sixteen subjects were recruited (6 with metabolic syndrome and 10 controls) and randomised to acipimox 250 mg orally every 6 h for 7 days or placebo. Nineteen subjects were recruited (13 with metabolic syndrome and 6 controls) and randomised to receive salsalate 4.5 g/day for 4 weeks or placebo. The primary outcome was the association between FFA concentration and insulin-mediated vasodilation, measured by venous-occlusion strain-gauge plethysmography at baseline and following FFA modulation with the study drugs.

RESULTS

At baseline, FFA concentration (R = -0.35, p = 0.043) and insulin sensitivity (HOMA-IR: R = -0.42, p = 0.016, Adipo-IR: R = -0.39, p = 0.025) predicted insulin-mediated vasodilation. FFA levels were significantly reduced after drug pretreatment (0.604 vs. 0.491 mmol/L, p = 0.036) while insulin levels, insulin sensitivity and inflammatory markers were unchanged. Despite a reduction in circulating FFA with drug therapy, neither insulin-stimulated vasodilation nor insulin sensitivity improved.

CONCLUSIONS

Short-term reduction of FFA concentration does not improve insulin-stimulated vasodilation in patients with metabolic syndrome.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00759291 and NCT00760019 (formerly NCT00762827).

Association between metabolic score for insulin resistance and stroke: a nationally representative cross-sectional study from NHANES 2007-2018

Background

Stroke is a significant cerebrovascular disease and remains one of the leading causes of death and disability worldwide. Insulin resistance has been strongly linked to the incidence of stroke. Employing characteristics of metabolic syndrome, the Metabolic Score for Insulin Resistance (METS-IR) accurately measures insulin resistance. Nonetheless, the relationship between METS-IR and stroke risk is not well-established.

Methods

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) covering the years 2007-2018. Participants providing complete METS-IR data and self-reported stroke information were included in the study. We utilized weighted multivariate regression to explore the relationship between METS-IR and stroke, performing subgroup analyses as well.

Results

A total of 14,794 participants were included, with an average METS-IR of 43.44 ± 12.68. The overall prevalence of self-reported stroke was 3.79%, with higher rates observed in upper METS-IR tertiles. An increase of one unit in METS-IR was associated with a 1% increase in stroke risk (OR = 1.01; 95% CI: 1.01-1.02). Interaction tests indicated no significant effects of gender, smoking status, alcohol consumption, hypertension, diabetes, physical activity, or serum cholesterol levels on this relationship. Notably, for participants younger than 60 years, the association was significantly stronger (OR = 1.02; 95% CI: 1.01-1.03), with a marked interaction (p = 0.0061).

Conclusion

Our findings indicate a positive correlation between higher METS-IR and increased stroke risk. Early intervention targeting insulin resistance may be a viable preventive measure against stroke, particularly in individuals under 60 years of age.

Endothelial dysfunction in subfertile women with polycystic ovary syndrome

RESEARCH QUESTION

Is there an association between post-occlusive reactive hyperaemia (PORH) and ovarian stimulation in women with normoandrogenaemic polycystic ovary syndrome (PCOS)?

DESIGN

Women eligible for IVF at an academic fertility centre were invited to join this prospective study. Microvascular endothelial function was measured as PORH by laser Doppler flowmetry (LDF) before and after ovarian stimulation. Metabolic characteristics, hormone profiles and biochemical markers were analysed.

RESULTS

Thirty-four normoandrogenaemic women with PCOS and 36 normoandrogenaemic women without PCOS were included. The PCOS group displayed higher C-reactive protein levels and insulin resistance (P = 0.048 and P = 0.025, respectively). No significant difference was found in microcirculatory function between the groups at baseline. After ovarian stimulation, PORH was enhanced in the control group (slope 7.1 ± 3.3 versus 9.7 ± 4.5; P = 0.007; peak flow 30.7 ± 16.3 versus 43.5 ± 17.3, P = 0.008; however, the PCOS group experienced a blunting response to supraphysiological hormone status (slope 8.2 ± 5.1 versus 7.2 ± 4.3, P = 0.212; peak flow, 38.8 ± 19.4 versus 37.0 ± 21.8, P = 0.895).

CONCLUSIONS

Impaired microcirculatory function could be found using a non-invasive LDF technique in normoandrogenaemic women with PCOS undergoing IVF, indicating early changes in vascular endothelial dysfunction. Future observational studies should clarify whether PORH measurement might help predict IVF prognosis or obstetric complications.

Interleukin-17A is associated with flow-mediated dilation and interleukin-4 with carotid plaque in persons with HIV

OBJECTIVE

Chronic inflammation contributes to the high burden of cardiovascular disease (CVD) in persons with HIV (PWH). HIV has broad effects on innate and adaptive immune cells, including innate lymphoid cells (ILCs) and CD4+ T-helper cells. At present, the relationship between CVD and plasma cytokines reflecting ILC/T-helper responses in PWH is not well defined. We investigated relationships between plasma cytokines and subclinical atherosclerosis.

DESIGN

A cross-sectional study.

METHODS

We recruited 70 PWH on a single antiretroviral regimen (efavirenz, teno- fovir, and emtricitabine) with at least 12 months of suppressed viremia and 30 HIVnegative controls. We quantified plasma cytokines and chemokines, including inter- feron-g, interleukin (IL)-4, IL-13, and IL-17A, markers of macrophage activation, and markers of endothelial activation using multiplex assays and ELISA. Cytokines were grouped using Ward's hierarchical clustering. Brachial artery flow-mediated dilation (FMD) and carotid plaque burden were determined using ultrasound. Multivariable linear regression and negative binomial regression analyses were used to assess the relationships of plasma biomarkers and endpoints adjusted for CVD risk factors.

RESULTS

We identified three distinct clusters in PWH, one containing Th1/Th2/ILC1/ ILC2 type cytokines, one with Th17/ILC3/macrophage-related cytokines, and a less specific third cluster. Lower FMD was associated with higher plasma IL-17A and macrophage inflammatory protein-1 a. In contrast, IL-4, a Th2/ILC2 type cytokine, was associated with carotid plaque. When HIV-negative controls were added to the models clustering was more diffuse, and these associations were attenuated or absent.

CONCLUSION

Th17/ILC3 and Th2/ILC2-mediated immune mechanisms may have distinct roles in endothelial dysfunction and atherosclerotic plaque formation, respectively, in PWH.

Comprehensive Meta-Analysis of Functional and Structural Markers of Subclinical Atherosclerosis in Women with Polycystic Ovary Syndrome

The relationship between polycystic ovary syndrome (PCOS) and subclinical atherosclerosis remains unclear. We performed a comprehensive systematic review and meta-analysis to evaluate the effect of PCOS on functional and structural markers of subclinical atherosclerosis as measured by carotid intima-media thickness (cIMT), flow-mediated vasodilation (FMD), nitroglycerin-mediated vasodilation (NMD), pulse wave velocity (PWV), and coronary artery calcium (CAC). Standard mean differences (SMDs) or odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated. Ninety-six articles involving 5550 PCOS patients and 5974 controls were included. Compared with controls, PCOS patients showed significantly thicker cIMT (SMD (95% CI) = .587 (.398, .776), P < .001), lower FMD (SMD (95% CI) = -.649 (-.946, -.353), P < .001) and NMD (SMD (95% CI) = -.502 (-.686, -.317), P < .001), as well as higher PWV (SMD (95% CI) = .382 (.019, .746), P = .039), and increased CAC incidence (OR (95% CI) = 2.204 (1.687, 2.879), P < .001). When analyzing subgroups by age and body mass index (BMI), results were still significant (P < .05) except for PWV in the BMI subgroup. There was no significant result on sensitivity analysis, and Begg' test or Egger's test. PCOS contributes to subclinical atherosclerosis, resulting in functional and structural changes in cIMT, FMD and NMD, PWV, and CAC incidence.

Assessment of Early Markers of Cardiovascular Risk in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome, with long-term sequelae from birth to senescence. The long-term effects of PCOS are attributed to several metabolic aberrations ensuing the syndrome. In a systematic review of literature regarding the cardiovascular risk factors that accompany PCOS, we found that macrovascular function has been assessed by flow-mediated dilatation (FMD), microvascular function by venous occlusion plethysmography (VOP), and arterial structure by ultrasonographic assessment of intima-media thickness (IMT) usually of the carotid artery. Contradictory results have been reported; however, in most studies, endothelial dysfunction, an early marker of atherosclerosis assessed either by haemodynamic methods such as FMD or by biochemical methods such as endothelin-1 levels, was found to be impaired. VOP is a less-studied method, with few indices altered. IMT was found to be altered in most of the included studies, but the population was more heterogeneous. Inflammatory markers, including C-reactive protein, were also found to be altered in most studies. On the other hand, a number of interventions have been shown beneficial for the markers of cardiovascular risk, in the context of insulin-sensitizers. However, other interventions such as oral contraceptive pills or statins did not consistently show a similar beneficial effect. In summary, the early identification and eventual treatment of cardiovascular clinical and biochemical risk factors may be used in clinical practice to prevent potential 'silent' triggers of cardiovascular disease.

Anticytomegalovirus CD4+ T Cells Are Associated With Subclinical Atherosclerosis in Persons With HIV

[Figure: see text].

Assessment of Early Markers of Cardiovascular Risk in Polycystic Ovary Syndrome

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Postprandial microvascular blood flow in skeletal muscle: Similarities and disparities to the hyperinsulinaemic-euglycaemic clamp

Skeletal muscle contributes to ~40% of total body mass and has numerous important mechanical and metabolic roles in the body. Skeletal muscle is a major site for glucose disposal following a meal. Consequently, skeletal muscle plays an important role in postprandial blood glucose homeostasis. Over the past number of decades, research has demonstrated that insulin has an important role in vasodilating the vasculature in skeletal muscle in response to an insulin infusion (hyperinsulinaemic-euglycaemic clamp) or following the ingestion of a meal. This vascular action of insulin is pivotal for glucose disposal in skeletal muscle, as insulin-stimulated vasodilation increases the delivery of both glucose and insulin to the myocyte. Notably, in insulin-resistant states such as obesity and type 2 diabetes, this vascular response of insulin in skeletal muscle is significantly impaired. Whereas the majority of work in this field has focussed on the action of insulin alone on skeletal muscle microvascular blood flow and myocyte glucose metabolism, there is less understanding of how the consumption of a meal may affect skeletal muscle blood flow. This is in part due to complex variations in glucose and insulin dynamics that occurs postprandially-with changes in humoral concentrations of glucose, insulin, amino acids, gut and pancreatic peptides-compared to the hyperinsulinaemic-euglycaemic clamp. This review will address the emerging body of evidence to suggest that postprandial blood flow responses in skeletal muscle may be a function of the nutritional composition of a meal.

Conflicting effects of atazanavir therapy on atherosclerotic risk factors in stable HIV patients: A randomized trial of regimen switch to atazanavir

Bilirubin acts as a potent endogenous antioxidant, with higher concentrations associated with lower rates of CVD; the antiretroviral drug atazanavir (ATV) increases bilirubin levels but may also increase von Willebrand factor levels. We tested the hypothesis that increasing endogenous bilirubin using ATV would improve cardiometabolic risk factors and vascular function in older patients with HIV. Ninety participants were enrolled in two study protocols. In protocol 1, we evaluated markers of inflammation, thrombosis, and conduit artery endothelial function in subjects on non-ATV containing regimens. Participants were randomly assigned to continue baseline treatment or switch to an ATV-based regimen. Measurements were made at baseline and 28 days. In the protocol 2, we enrolled 30 subjects who received atazanavir for more than one year and were compared to the aim 1 protocol subjects at baseline. 60 subjects were enrolled in the first protocol (mean age 53, +/- 6 years), with 31 randomized to ATV and 29 continuing baseline treatment. Atazanavir significantly increased serum total bilirubin levels (p<0.001) and acutely but not chronically plasma total antioxidant capacity (p<0.001). An increase in von Willebrand Factor (p<0.001) and reduction in hs-CRP (p = 0.034) were noted. No changes were seen in either flow-mediated endothelium-dependent or vasodilation. In cross-sectional analysis (second protocol), similar findings were seen in the baseline attributes of non-atazanavir-based and long-term atazanavir users. Increasing serum bilirubin levels with atazanavir in subjects with HIV reduces hs-CRP, temporarily reduces oxidative stress, but increases von Willebrand Factor. Atazanavir does not improve endothelial function of conduit arteries.

Trial registration: ClinicalTrials.gov NCT03019783.

Atazanavir improves cardiometabolic measures but not vascular function in patients with long-standing type 1 diabetes mellitus

AIMS

Vascular disease is the leading cause of morbidity and mortality in type 1 diabetes mellitus (T1DM). We previously demonstrated that patients with T1DM have impaired endothelial function, a forme fruste of atherosclerosis, as a result of increased oxidative stress. Bilirubin has emerged as a potent endogenous antioxidant with higher concentrations associated with lower rates of myocardial infarction and stroke.

METHODS

We tested the hypothesis that increasing endogenous bilirubin using atazanavir would improve cardiometabolic risk factors and vascular function in patients with T1DM to determine whether targeting bilirubin may be a novel therapeutic approach to reduce cardiovascular disease risk in this population. In this single-arm, open-label study, we evaluated blood pressure, lipid profile, and conduit artery function in fifteen subjects (mean age 45 ± 9 years) with T1DM following a 4-day treatment with atazanavir.

RESULTS

As anticipated, atazanavir significantly increased both serum total bilirubin levels (p < 0.0001) and plasma total antioxidant capacity (p < 0.0001). Reductions in total cholesterol (p = 0.04), LDL cholesterol (p = 0.04), and mean arterial pressure (p = 0.04) were also observed following atazanavir treatment. No changes were seen in either flow-mediated endothelium-dependent (p = 0.92) or nitroglycerine-mediated endothelium-independent (p = 0.68) vasodilation, measured by high-resolution B-mode ultrasonography at baseline and post-treatment.

CONCLUSION

Increasing serum bilirubin levels with atazanavir in subjects with T1DM over 4 days favorably reduces LDL and blood pressure but is not associated with improvements in endothelial function of conduit arteries.

Association of clinical androgen excess with radial artery intima media thickness in women with polycystic ovary syndrome

This study explores the relationship between clinical cardiovascular risk factors and clinical androgen excess, with direct comparison to radial artery intima media thickness (rIMT). rIMT of 91 patients with polycystic ovary syndrome (PCOS) were compared with 72 healthy women. Patients were divided into three groups with regard to body mass index (BMI). Group1 = 56 women (31 controls and 25 PCOS) with low BMI(18-22.49 kg/m(2)), Group2 = 36 women (15 controls and 21 PCOS) with normal BMI (22.5-24.99 kg/m(2)) and Group3 = 71 women (26 controls and 45 PCOS) with high BMI (25-30 kg/m(2)). rIMT was significantly higher in patients with PCOS (p = 0.007). rIMT was significantly higher group1 and group3 in patients with PCOS compared to controls (p = 0.007 and p = 0.042, respectively). There was a significant positive association between rIMT levels and fT in women with PCOS in group1 (r = 0.24, p = 0.04). rIMT levels correlated to fT levels in women with PCOS in group3 (r = 0.32, p = 0.03). Modified Ferriman-Gallwey (mFG) scores demonstrated a positive association with free testosterone, total testosterone, free androgen index, waist circumference (WC), LH levels, insulin levels, Homeostasis Model Assessment index(HOMA-IR), rIMT and a negative correlation with sex hormone binding globulin in group1 and group2. mFG scores demonstrated a positive association with free testosterone (r = 0.33, p = 0.029) in group3, but no association was found between mFG and WC, HOMA-IR in group3. Our findings indicate that clinical androgen excess may be associated with cardiovascular disease in patients with PCOS.

Androgen deprivation therapy reversibly increases endothelium-dependent vasodilation in men with prostate cancer

Background

Androgen deprivation therapy (ADT) is a standard treatment for patients with aggressive prostate cancer. Although ADT improves survival, it increases the risk of diabetes. Emerging evidence suggests that ADT increases adverse cardiovascular events as early as 3 months after initiation in patients with cardiovascular disease, but the mechanism is unknown. We hypothesized that ADT may impair endothelium‐dependent vasodilation due to increases in lipids and insulin resistance and may provide a link for heightened cardiovascular risk in this population.

Methods and Results

We prospectively evaluated conduit artery endothelium‐dependent and ‐independent vasodilation, lipids, and insulin resistance in 16 consecutively treated men (mean age 66±7 years; 25% with diabetes) with prostate cancer before and after 3 months of ADT. High‐resolution B‐mode ultrasound was used to assess flow‐mediated (endothelium‐dependent) and nitroglycerine‐mediated (endothelium‐independent) brachial artery vasodilation. ADT significantly increased insulin resistance, total cholesterol, HDL, and LDL. Endothelium‐dependent vasodilation was greater at 3 months than at baseline (10.8% [interquartile range: 7.7% to 14.6%] versus 8.9% [interquartile range: 4.0% to 12.6%], respectively; P=0.046, allometric P=0.037). Nitroglycerine‐mediated vasodilation did not change from baseline (P>0.2). The subset of participants on ADT for 6 months returned for reevaluation at 1 year. In this group, endothelium‐dependent vasodilation increased from baseline to 3 months and returned to baseline 6 months after ADT withdrawal (9.4% [interquartile range: 6.9% to 10.9%], 11.6% [interquartile range: 7.9% to 15.2%], and 9.0% [interquartile range: 5.1% to 12.5%], respectively; P=0.05).

Conclusions

In contrast to our expectation, ADT improved endothelium‐dependent vasodilation and its cessation returned endothelium‐dependent vasodilation to baseline. Determining the mechanism of this change requires further investigation.

Evaluation of endothelium functions by flow-mediated dilatation in pediatric patients with Crimean-Congo hemorrhagic fever

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a systemic viral disease that also affects the endothelium. Thrombocytopenia and hemorrhage are seen in this disease. But, the cause of thrombocytopenia is not clear. We hypothesized that endothelium dysfunction may be the cause of thrombocytopenia. We evaluated the endothelium functions by flow-mediated dilatation (FMD) in CCHF.

METHODS

Consecutive children with suspected CCHF who applied to our hospital were evaluated for recruitment into the study. FMD analysis was done in the active and healing period of the disease. Diagnosis was confirmed or ruled out by polymerase chain reaction and/or ELISA test. Basal brachial artery diameter (BBAD) and dilated brachial artery diameter (DBAD) after ischemic period were measured and percent dilatations [(DBAD-BBAD)/BBAD, FMD%] were computed from all subjects.

RESULTS

Fifty-four children (40 male, mean age 12.4 ± 4.4 years) were recruited into the study. CCHF diagnosis was confirmed in 28 children and ruled out in 26 children. Groups were similar for age and gender. FMD% was significantly decreased in CCHF patients when comparing this with the control patients in the active period (2.65 ± 2.76 vs. 13.76 ± 7.95, P < 0.001). FMD% was correlated with platelet count in the active period of the disease (r = 0.599, P = 0.004). FMD% was recovered in the healing period (2.65 ± 2.76 vs. 14.72 ± 2.66, P < 0.001) and was not significantly different from basal values of control patients (P > 0.05).

CONCLUSIONS

FMD is significantly decreased in CCHF and recovers in the healing period. So, endothelium functions are disturbed, and disturbance is correlated with thrombocytopenia in CCHF.

Diagnosis and treatment of polycystic ovary syndrome: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and treatment of polycystic ovary syndrome (PCOS).

PARTICIPANTS

An Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer developed the guideline.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines. Two systematic reviews were conducted to summarize supporting evidence.

CONCLUSIONS

We suggest using the Rotterdam criteria for diagnosing PCOS (presence of two of the following criteria: androgen excess, ovulatory dysfunction, or polycystic ovaries). Establishing a diagnosis of PCOS is problematic in adolescents and menopausal women. Hyperandrogenism is central to the presentation in adolescents, whereas there is no consistent phenotype in postmenopausal women. Evaluation of women with PCOS should exclude alternate androgen-excess disorders and risk factors for endometrial cancer, mood disorders, obstructive sleep apnea, diabetes, and cardiovascular disease. Hormonal contraceptives are the first-line management for menstrual abnormalities and hirsutism/acne in PCOS. Clomiphene is currently the first-line therapy for infertility; metformin is beneficial for metabolic/glycemic abnormalities and for improving menstrual irregularities, but it has limited or no benefit in treating hirsutism, acne, or infertility. Hormonal contraceptives and metformin are the treatment options in adolescents with PCOS. The role of weight loss in improving PCOS status per se is uncertain, but lifestyle intervention is beneficial in overweight/obese patients for other health benefits. Thiazolidinediones have an unfavorable risk-benefit ratio overall, and statins require further study.

Endothelial function measured using flow-mediated dilation in polycystic ovary syndrome: a meta-analysis of the observational studies

OBJECTIVE

Women with polycystic ovary syndrome (PCOS) demonstrate an increased prevalence of cardiovascular disease (CVD) risk factors. Previous researchers have compared flow-mediated dilation (FMD), an early marker of CVD, in women with and without PCOS. Evidence for a PCOS-mediated reduction in FMD remains equivocal, potentially because of study differences in cohort-matching and measurement approaches. The aims of this systematic review and meta-analysis were to examine to what extent FMD is impaired in PCOS and to explore the influence of potential moderators of FMD reduction, such as age and BMI.

DESIGN

A systematic review and meta-analysis of published observational studies comparing FMD in PCOS with control women.

PATIENTS

Twenty-one published studies were included (PCOS, n = 908; controls, n = 566). A subanalysis, using tighter inclusion criteria, involved seven studies (PCOS, n = 402; control, n = 251).

MEASUREMENTS

Mean differences in FMD between PCOS and controls were synthesized. The subanalysis was delimited to the inclusion of age and BMI-matched controls. These factors were then explored as moderators using meta-regression.

RESULTS

The pooled mean FMD was 3.4% (95% CI=1.9, 4.9) lower in PCOS compared with control women, with substantial heterogeneity between studies. In the subanalysis, the PCOS-mediated reduction in FMD was 4.1% (95% CI=2.7, 5.5). Heterogeneity remained substantial (I(2) =81%). Subsequent meta-regression indicated that the magnitude of FMD difference was not influenced by BMI (P = 0.17) nor age (P = 0.38).

CONCLUSIONS

This systematic research synthesis indicates that endothelial function is compromised in PCOS women, even if they are young and nonobese.

Serum asymmetric dimethylarginine, apelin, and tumor necrosis factor-α levels in non-obese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with multiple risk factors for cardiovascular disease (CVD), including insulin resistance, type 2 diabetes mellitus, obesity, hypertension, and dyslipidemia. In addition, hyperandrogenism may contribute to the pathogenesis of CVD, independent of obesity and insulin resistance. We investigated serum levels of asymmetric dimethylarginine (ADMA), apelin, and tumor necrosis factor (TNF)-α as CVD risk markers and their relationship with hyperandrogenism in non-obese women with PCOS. In this study were included 82 non-obese women with PCOS and 33 controls. Women with PCOS were further divided into two groups: women with hyperandrogenism (HA-PCOS, n=37) and those without hyperandrogenism (NA-PCOS, n=45). Serum ADMA, apelin, and TNF-α levels were compared among the three groups and their relationship with hyperandrogenism was evaluated. Serum ADMA levels were significantly higher in the HA-PCOS group than in the NA-PCOS and control groups (0.45 ± 0.09 vs. 0.38 ± 0.08 vs. 0.40 ± 0.07; P<0.0005). Serum TNF-α levels were significantly higher among women with PCOS compared with controls (2.91 ± 1.25 vs. 1.74 ± 0.77; P<0.001) and in the HA-PCOS group compared with the NA-PCOS group (3.21 ± 1.24 vs. 2.60 ± 1.24; P<0.0001). Both PCOS groups had significantly lower serum apelin levels compared with controls (1.31 ± 0.54 vs. 1.16 ± 0.34 vs. 2.78 ± 1.10; P<0.0001). ADMA and TNF-α were positively correlated with total testosterone (r=0.219, P=0.022; r=0.332, P<0.001, respectively) and free androgen index (r=0.287, P=0.002; r=0.289, P=0.002, respectively), whereas apelin was negatively correlated with these parameters (r=-0.362, P<0.001; r=-0.251, P=0.008). These findings may indicate that non-obese women with PCOS are at an increased risk for CVD, which is further aggravated by hyperandrogenism.

Vascular effects of intravenous intralipid and dextrose infusions in obese subjects

Hyperglycemia and elevated free fatty acids (FFA) are implicated in the development of endothelial dysfunction. Infusion of soy-bean oil-based lipid emulsion (Intralipid®) increases FFA levels and results in elevation of blood pressure (BP) and endothelial dysfunction in obese healthy subjects. The effects of combined hyperglycemia and high FFA on BP, endothelial function and carbohydrate metabolism are not known. Twelve obese healthy subjects received four random, 8-h IV infusions of saline, Intralipid 40 mL/h, Dextrose 10% 40 mL/h, or combined Intralipid and dextrose. Plasma levels of FFA increased by 1.03±0.34 mmol/L (p=0.009) after Intralipid, but FFAs remained unchanged during saline, dextrose, and combined Intralipid and dextrose infusion. Plasma glucose and insulin concentrations significantly increased after dextrose and combined Intralipid and dextrose (all, p<0.05) and were not different from baseline during saline and lipid infusion. Intralipid increased systolic BP by 12±9 mmHg (p<0.001) and diastolic BP by 5±6 mmHg (p=0.022),and decreased flow-mediated dilatation (FMD) from baseline by 3.2%±1.4% (p<0.001). Saline and dextrose infusion had neutral effects on BP and FMD. The co-administration of lipid and dextrose decreased FMD by 2.4%±2.1% (p=0.002) from baseline, but did not significantly increase systolic or diastolic BP. Short-term Intralipid infusion significantly increased FFA and BP; in contrast, FFA and BP were unchanged during combined infusion of Intralipid and dextrose. Combined Intralipid and dextrose infusion resulted in endothelial dysfunction similar to Intralipid alone.

In vivo nitric oxide synthesis, insulin sensitivity, and asymmetric dimethylarginine in obese subjects without and with metabolic syndrome

Metabolic syndrome (MetSyn) is associated with impaired endothelial function. Here the association between nitric oxide (NO) production and insulin sensitivity (Si) in obese subjects with and without MetSyn was evaluated. The relationship between NO production and asymmetric dimethylarginine (ADMA) was also explored. Seven healthy normal-weight subjects (male/female [M/F], 3/4; age, 27.4 ± 10.9 years; body mass index [BMI], 21.9 ± 2.2 kg/m(2)), 7 obese subjects without MetSyn (M/F, 1/6; age, 48.0 ± 8.0 years; BMI, 34.5 ± 2.3 kg/m(2)), and 7 with MetSyn (M/F, 3/4; age, 48.0 ± 10.7 years; BMI, 33.4 ± 2.9 kg/m(2)) were recruited. Body composition and cardiometabolic functions (blood pressure, glucose, insulin, triglycerides, total cholesterol, high-density lipoprotein, ADMA) were measured. A frequent sampling intravenous glucose tolerance test was performed to measure Si. A novel stable isotopic method was used to measure in vivo rates of NO production. The NO production was lower in obese subjects with MetSyn compared with normal-weight subjects and obese subjects without MetSyn. Similarly, Si was significantly lower in obesity, both without and with MetSyn, compared with the control group. A significant direct association was found between NO synthesis and Si (ρ = 0.47, P = .03). Circulating levels of ADMA were significantly higher in the obese group with MetSyn. A nonsignificant negative trend between ADMA and NO synthesis was observed. The association between Si and NO production suggests a close mechanistic link between endothelial function and insulin signaling. The results may be highly informative for the development of controlled longitudinal interventions to improve endothelial and metabolic regulation.

Polycystic Ovary Syndrome and Chronic Inflammation: Pharmacotherapeutic Implications

Objective:

To examine the relationship between polycystic ovary syndrome (PCOS), cardiovascular risk factors, cardiovascular disease (CVD), and chronic inflammation and analyze data regarding pharmacologic therapies that are recommended to reduce CVD risk in PCOS and the impact of those therapies on chronic inflammation.

Data Sources:

A search of MEDLINE (1950-October 2011) was conducted to identify clinical studies pertaining to the identification and treatment of CVD and chronic low-grade inflammation in PCOS, Search terms included polycystic ovary syndrome, cardiovascular disease, inflammation, metformin, thiazolidinedione, and statin. Bibliographies of these studies and review articles were also examined.

Study Selection and Data Extraction:

English-language clinical studies evaluating the effect of metformin, thiazolidinediones, and statins on inflammatory markers, endothelial function, adhesion molecules, fibrinolysis, cytokines, and adipokines in PCOS were included.

Data Synthesis:

Women with PCOS have an increased prevalence of many cardiovascular risk factors including obesity, android fat distribution, insulin resistance, impaired glucose tolerance, diabetes, dyslipidemia, hypertension, and metabolic syndrome. Markers of chronic low-grade inflammation, which are associated with an increased risk of CVD, are also elevated in PCOS. Clinical guidelines recommend the use of insulin sensitizers and statins to prevent CVD in some patients with PCOS. Current literature indicates that each of these medication classes has beneficial effects on inflammation, as well. Although there are currently no studies to determine whether these treatments decrease CVD in PCOS, it can be hypothesized that drugs impacting chronic inflammation may reduce cardiovascular risk. Some studies show that metformin, thiazolidinediones, and statins have beneficial effects on inflammatory markers in PCOS; however, the data are inconsistent.

Conclusions:

There is insufficient information to recommend any pharmacologic therapies for their antiinflammatory effects in PCOS in the absence of other indications such as diabetes and dyslipidemia.

Evaluation of early atherosclerotic findings in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of childbearing age, and it seems better to consider it as an ovarian manifestation of metabolic syndrome. The aim of the current study was to evaluate early atherosclerotic findings in patients with PCOS.

METHODS

We enrolled 46 women with PCOS and 45 normal control subjects who were referred to our hospital's endocrinology outpatient clinic. Carotid intima media thickness (CIMT) and flow-mediated dilatation (FMD) were performed in both cases and matched controls.

RESULTS

Patients with PCOS showed an increased mean CIMT (0.63 ± 0.16 mm) when compared with the control subjects (0.33 ± 0.06 mm). This difference was statistically significant (p = 0.001). The mean FMD in young patients with PCOS was 10.07 ± 1.2%, while it was 6.5 ± 2.06% in normal subjects. This difference was also statistically significant (p = 0.001).

CONCLUSION

Our findings suggest that PCOS is related with early atherosclerotic findings.

Exercise attenuates the premature cardiovascular aging effects of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2D) is an example of a disease process that results in decrements in function additional to those imposed by the inexorable 'primary aging' process. These decrements due to disease, rather than primary aging, can be termed 'secondary aging', and include the premature development (as early as adolescence) of asymptomatic preclinical cardiovascular abnormalities (e.g. endothelial dysfunction, arterial stiffness, diastolic dysfunction), as well as impaired exercise performance. These abnormalities are important, as they are associated with greater cardiovascular morbidity and mortality in people with and without T2D. A better understanding of the pathophysiology of secondary cardiovascular aging in people with T2D is warranted, and an evaluation of the benefits of existing treatments for these abnormalities is useful (e.g. exercise training). The focus of this review is to discuss the data relevant to the following key postulates: (a) T2D causes premature cardiovascular aging; (b) in contrast to primary cardiovascular aging, the premature cardiovascular aging of T2D may be modifiable with exercise. The exercise-focused perspective for this review is appropriate because impairments in exercise performance are markers of premature cardiovascular aging in T2D, and also because exercise training shows promise to attenuate some aspects of cardiovascular aging during the preclinical stage.

Meta-analysis of cardiovascular disease risk markers in women with polycystic ovary syndrome

BACKGROUND

The relation between polycystic ovary syndrome (PCOS) and cardiovascular disease (CVD) remains unclear. In an attempt to provide high-quality evidence on the relation between PCOS and CVD, relevant literature for CVD risk markers [C-reactive protein (CRP), homocysteine (Hcy), tumor necrosis factor-alpha (TNF-α), plasminogen activator inhibitor-1 (PAI-1), lipoprotein (a) [Lp(a)], advanced glycation end-products (AGEs), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1) and fibrinogen] in women with PCOS was reviewed and analyzed.

METHODS

A systematic search was conducted electronically using specific eligibility criteria. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated and combined appropriately. To ensure synthesis of the best available evidence, sensitivity analyses were performed. RESULTS A total of 130 data sets were included in 11 different outcomes, involving 7174 and 5076 CVD markers in women with PCOS and controls, respectively. Women with PCOS demonstrated significantly elevated CRP [WMD (95% CI) 0.99 (0.77-1.21)], Hcy [2.25 (1.46-3.03)], PAI-1 antigen [16.96 (7.25-26.28)], PAI-1 activity [0.71 (0.18-1.23)], VEGF [1.72 (0.96-2.48)], ADMA [0.19 (0.08-0.3)], AGEs [3.91 (2.36-5.45)] and Lp(a) [0.81 (0.58-1.04)] concentrations compared with controls, yet with significant between-study heterogeneity. Borderline significance (not robust in the sensitivity analyses) was detected for TNF-α [0.75 (0.07-1.44)], ET-1 [1.06 (0.52-1.59)] and fibrinogen [0.20 (0.01-0.39)], whereas no difference was detected for IL-6 [0.71 (-0.16 to 1.59)]. CONCLUSIONS Women with PCOS have increased serum concentrations of CVD risk markers compared with controls. Whether this apparent risk is translated into increased incidence of CVD in later life remains to be elucidated.

Circulating inflammatory markers in polycystic ovary syndrome: a systematic review and metaanalysis

OBJECTIVE

To perform a review and metaanalysis of the studies evaluating the status of serum inflammatory markers in women with polycystic ovary syndrome (PCOS).

DESIGN

Systematic review and metaanalysis of articles published in English before January 2010 and identified using the PubMed search engine.

SETTING

Academic hospital.

PATIENT(S)

Women with PCOS and appropriate controls.

INTERVENTION(S)

Measurement of serum concentrations of inflammatory markers by high-sensitivity techniques.

MAIN OUTCOME MEASURE(S)

Metaanalyses of the mean difference in serum C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations among patients with PCOS and appropriate controls, applying random-effects models to limit interstudy variability, and using appropriate estimates of evidence dissemination bias.

RESULT(S)

Metaanalysis of the 31 articles meeting inclusion criteria showed that circulating CRP was 96% higher in women with PCOS compared to controls (95% confidence interval, 71%-122%; z = 7.32) without evidence of dissemination bias (Egger's regression intercept, 0.45; 95% confidence interval, -2.30 to 3.21). These findings persisted after excluding five studies with mismatches in body mass, frequency of obesity, or both, between women with PCOS and controls. Metaanalyses involving 10 studies of IL-6, and nine studies of TNF-α revealed no statistically significant differences between PCOS and controls.

CONCLUSION(S)

Women with PCOS exhibit an elevation in circulating CRP that is independent of obesity. This finding corroborates existing molecular evidence of the chronic low-grade inflammation that may underpin the pathogenesis of this disorder.

Influence of visceral obesity and liver fat on vascular structure and function in obese subjects

Endothelial dysfunction and increased intima-media thickness (IMT) have been found in obese patients. Both regional fat distribution and liver steatosis may influence these markers of subclinical atherosclerosis. We sought to determine the interrelationships of endothelial function, carotid IMT, visceral and subcutaneous adipose tissue accumulation, and liver steatosis in severely obese subjects. In 64 severely obese patients (BMI 42.3 +/- 4.3 kg/m(2)), we determined (i) endothelial function as flow-mediated dilation (FMD) of the brachial artery, (ii) carotid IMT, (iii) visceral fat diameter, and (iv) degree of liver steatosis using ultrasound. FMD was associated inversely with visceral fat diameter and degree of steatosis (r = -0.577, P < 0.0001 and r = -0.523, P < 0.0001, respectively). Carotid IMT correlated with visceral fat mass (r = 0.343, P = 0.007) but not with liver steatosis. After adjustment for conventional cardiovascular risk factors, FMD was predicted independently by the visceral fat diameter, age, and sex (r(2) = 0.48, P < 0.0001), but not by the degree of liver steatosis or plasma adiponectin levels. In contrast, age and sex were the only predictors of IMT (r(2) = 0.33, P < 0.001). In obese patients, visceral fat diameter is a major determinant of endothelial dysfunction, independent of traditional risk factors or the degree of liver steatosis and plasma adiponectin. Measurement of visceral fat diameter by ultrasound is a novel and simple method to identify subjects with an increased risk for atherosclerosis within an obese population.

Effects of hypocaloric very-low-carbohydrate diet vs. Mediterranean diet on endothelial function in obese women*

Obesity is a cardiovascular risk factor associated with endothelial dysfunction, but the effect of different weight loss strategies on endothelial function is not known. The effect of diet on endothelial function in two hypocaloric diets, a very-low-carbohydrate diet (A) and a Mediterranean diet (M), was measured by brachial artery flow-mediated dilation (FMD). Design Using a longitudinal, randomized, open study design, subjects were engaged in a 2-month weight loss diet. FMD, inflammatory cytokines [interleukin-6 (IL-6) and tumour necrosis factor-alpha] and a marker of oxidative stress [8-iso-prostaglandin F2alpha (8-iso-PGF2alpha)] were measured in subjects on three occasions: before initiating the diet (T0), after 5-7 days of dieting (T5) and after 2 months of dieting (T60). The very short- and medium-term time points were established to discriminate respectively the effect of the diet itself (T5) from that of weight loss (T60). Twenty overweight/obese but otherwise healthy women (BMI: 27-34.9 kg m(-2); age 30-50 years) completed the study. Results Group A lost more weight (mean +/- SEM; -7.6 +/- 0.8 kg) than group M (-4.9 +/- 0.6 kg, P = 0.014) at T60. The FMD was not significantly different between the two groups at T0 (group A: 12.2 +/- 2.9% vs. group B: 10.3 +/- 2.3%, P = ns). In group A, FMD was significantly reduced at T5 and returned to baseline at T60; in group M, FMD increased at T5 and returned to baseline at T60 (P = 0.007 for diet x time interaction). Serum concentrations of IL-6 and 8-iso-PGF2alpha were not significantly different between the two groups at T0 and increased significantly at T5 only in group A (P < 0.001 and P < 0.005 respectively). Conclusion As endothelial dysfunction is known to be associated with acute cardiovascular events, this study suggests that the cardiovascular risk might be increased in the first days of a very-low-carbohydrate diet.

Effects of an antiandrogenic oral contraceptive pill compared with metformin on blood coagulation tests and endothelial function in women with the polycystic ovary syndrome: influence of obesity and smoking

OBJECTIVE

To study the blood clotting tests and endothelial function of polycystic ovary syndrome (PCOS) patients and non-hyperandrogenic women, and their changes during PCOS treatment, as a function of the presence of obesity and smoking.

DESIGN

Case-control study followed by a randomized clinical trial.

METHODS

Blood clotting and endothelial function were analyzed in 40 PCOS patients and 20 non-hyperandrogenic women. Thirty-four PCOS women were randomized to an oral contraceptive containing 35 microg ethinyl-estradiol plus 2 mg cyproterone acetate (Diane(35)Diario) or metformin (850 mg twice daily), monitoring the changes on these parameters during 24 weeks of treatment. The influence of obesity and smoking was also analyzed.

RESULTS

Blood clotting and endothelial function tests were similar among PCOS patients and controls with the exception of a higher platelet count in the former. Obesity increased circulating fibrinogen levels, prothrombin activity and platelet counts, and reduced prothrombin and activated partial thromboplastin times. Smoking increased fibrinogen levels, platelet counts, and prothrombin activity, and reduced prothrombin time, in relation to the larger waist circumference of smokers. Irrespective of the treatment received, PCOS patients showed a decrease in prothrombin time and an increase in prothrombin activity, with a parallel increase in homocysteine levels in metformin users. The activated partial thromboplastin time decreased markedly in the patients treated with Diane(35)Diario. Finally, flow-mediated dilation improved in non-smokers irrespective of the drug received, but worsened in smokers.

CONCLUSIONS

Oral contraceptives and metformin may exert deleterious effects on blood clotting tests of PCOS women, yet the effects of metformin appear to be milder. Because smoking potentiates some of these effects and deteriorates endothelial function, smoking cessation should be promoted in PCOS patients.

Relationship between brachial artery flow-mediated dilatation, hyperemic shear stress, and the metabolic syndrome

Abstract

Metabolic syndrome (MetSyn) may predispose to cardiovascular disease (CVD) by causing vascular dysfunction. This study aimed to determine the association of MetSyn with vascular function, as assessed by brachial artery flow-mediated dilatation (FMD) and hyperemic shear stress (HSS). A total of 1,417 male firefighters without established diabetes and CVD were classified for MetSyn, according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP) definition. MetSyn was present in 267 individuals (19%). Although FMD was lower in those with versus without MetSyn (8.1 ± 4.1 vs 8.7 ± 4.0%; p = 0.02), this was not significant after adjusting for baseline differences (age, smoking, and brachial artery diameter) ( p = 0.2). However, HSS was significantly lower in those with versus without MetSyn (72.0 ± 27.8 vs 80.9 ± 24.8 dyne/cm2; p < 0.001), and there was a significant inverse graded relationship with the number of NCEP criteria present (mean HSS for those with 0, 1, 2, 3, 4, and 5 criteria: 83.2 ± 22.5, 82.2 ± 24.7, 76.5 ± 27.2, 74.3 ± 27.4, 66.5 ± 28.4, 67.1 ± 27.6 dyne/cm2; p < 0.001 for trend). The individual NCEP criteria of abdominal obesity, systolic hypertension, and impaired fasting glucose were independent predictors for HSS. In conclusion, MetSyn was not associated with impaired FMD. Alternatively, HSS, a measure of microvascular function, was significantly lower in those with MetSyn. Thus, MetSyn may contribute to CVD by causing microvascular dysfunction.

Impaired microvascular perfusion: a consequence of vascular dysfunction and a potential cause of insulin resistance in muscle

Insulin has an exercise-like action to increase microvascular perfusion of skeletal muscle and thereby enhance delivery of hormone and nutrient to the myocytes. With insulin resistance, insulin's action to increase microvascular perfusion is markedly impaired. This review examines the present status of these observations and techniques available to measure such changes as well as the possible underpinning mechanisms. Low physiological doses of insulin and light exercise have been shown to increase microvascular perfusion without increasing bulk blood flow. In these circumstances, blood flow is proposed to be redirected from the nonnutritive route to the nutritive route with flow becoming dominant in the nonnutritive route when insulin resistance has developed. Increased vasomotion controlled by vascular smooth muscle may be part of the explanation by which insulin mediates an increase in microvascular perfusion, as seen from the effects of insulin on both muscle and skin microvascular blood flow. In addition, vascular dysfunction appears to be an early development in the onset of insulin resistance, with the consequence that impaired glucose delivery, more so than insulin delivery, accounts for the diminished glucose uptake by insulin-resistant muscle. Regular exercise may prevent and ameliorate insulin resistance by increasing "vascular fitness" and thereby recovering insulin-mediated capillary recruitment.