Endothelial function and its assessment

Serum Albumin-to-Creatinine Ratio: A Novel Predictor of Pulmonary Infection in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

AIM

In patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI), a low serum albumin-to-creatinine ratio (sACR) is associated with elevated risk of poor short- and long-term outcomes. However, the relationship between sACR and pulmonary infection during hospitalization in patients with STEMI undergoing PCI remains unclear.

METHODS

A total of 4,507 patients with STEMI undergoing PCI were enrolled and divided into three groups according to sACR tertile. The primary outcome was pulmonary infection during hospitalization, and the secondary outcome was in-hospital major adverse cardiovascular events (MACE) including stroke, in-hospital mortality, target vessel revascularization, recurrent myocardial infarction, and all-cause mortality during follow-up.

RESULTS

Overall, 522 (11.6%) patients developed pulmonary infections, and 223 (4.9%) patients developed in-hospital MACE. Cubic spline models indicated a non-linear, L-shaped relationship between sACR and pulmonary infection (P=0.039). Receiver operating characteristic curve analysis indicated that sACR had good predictive value for both pulmonary infection (area under the ROC curve [AUC]=0.73, 95% CI=0.70-0.75, P＜0.001) and in-hospital MACE (AUC=0.72, 95% CI=0.69-0.76, P＜0.001). Kaplan-Meier survival analysis indicated that higher sACR tertiles were associated with a greater cumulative survival rate (P＜0.001). Cox regression analysis identified lower sACR as an independent predictor of long-term all-cause mortality (hazard ratio [HR]=0.96, 95% CI=0.95-0.98, P＜0.001).

CONCLUSIONS

A low sACR was significantly associated with elevated risk of pulmonary infection and MACE during hospitalization, as well as all-cause mortality during follow-up among patients with STEMI undergoing PCI. These findings highlighted sACR as an important prognostic marker in this patient population.

Targeting Peptide, Fluorescent Reagent Modified Magnetic Liposomes Coated with Rapamycin Target Early Atherosclerotic Plaque and Therapy

Atherosclerosis is the leading cause of global morbidity and mortality. Its therapy requires research in several areas, such as diagnosis of early arteriosclerosis, improvement of the pharmacokinetics and bioavailability of rapamycin as its therapeutic agents. Here, we used the targeting peptide VHPKQHR (VHP) (or fluorescent reagent) to modify the phospholipid molecules to target vascular cell adhesion molecule-1 (VCAM-1) and loaded ultrasmall paramagnetic iron oxide (USPIO/Fe₃O₄) plus rapamycin (Rap) to Rap/Fe₃O₄@VHP-Lipo (VHPKQHR-modified magnetic liposomes coated with Rap). This nanoparticle can be used for both the diagnosis and therapy of early atherosclerosis. We designed both an ex vivo system with mouse aortic endothelial cells (MAECs) and an in vivo system with ApoE knockout mice to test the labeling and delivering potential of Rap/Fe₃O₄@VHP-Lipo with fluorescent microscopy, flow cytometry and MRI. Our results of MRI imaging and fluorescence imaging showed that the T2 relaxation time of the Rap/Fe₃O₄@VHP-Lipo group was reduced by 2.7 times and 1.5 times, and the fluorescence intensity increased by 3.4 times and 2.5 times, respectively, compared with the normal saline group and the control liposome treatment group. It showed that Rap/Fe₃O₄@VHP-Lipo realized the diagnosis of early AS. Additionally, our results showed that, compared with the normal saline and control liposomes treatment group, the aortic fluorescence intensity of the Rap/Fe₃O₄@VHP-Lipo treatment group was significantly weaker, and the T2 relaxation time was prolonged by 8.9 times and 2.0 times, indicating that the targeted diagnostic agent detected the least plaques in the Rap/Fe₃O₄@VHP-Lipo treatment group. Based on our results, the synthesized theragnostic Rap/Fe₃O₄@VHP-Lipo serves as a great label for both MRI and fluorescence bimodal imaging of atherosclerosis. It also has therapeutic effects for the early treatment of atherosclerosis, and it has great potential for early diagnosis and can achieve the same level of therapy with a lower dose of Rap.

Hypertriglyceridemic Waist in Patients with Type 2 Diabetes: Its Relationship to Selected Markers of Vascular Damage

Background: To evaluate the association between hypertriglyceridemic waist (HTGW), a promising marker of visceral adiposity and cardiovascular (CV) risk, and different indicators of vascular damage in type 2 diabetes (T2D) patients. Methods: This case-control study included 161 patients with T2D (91 males, 70 females) and 40 healthy controls (24 males, 16 females). HTWG was defined as waist circumference >90 cm in men or >85 cm in women and triglyceride concentrations >2 mmol/L. In addition to anthropometric and metabolic parameters, markers of endothelial dysfunction, namely von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1), were assessed. Arterial stiffness parameters were examined using the SphygmoCor system. Results: Individuals with T2D and HTGW showed the highest elevation of PAI-1 levels and significantly increased vWF levels compared with healthy controls. No significant differences in arterial stiffness markers were observed between T2D individuals. Age and, for several markers, systolic and/or diastolic blood pressure were identified as the main predictors for arterial stiffness, whereas PAI-1 and vWF levels were predicted by metabolic parameters. Conclusions: HTGW represents increased CV risk in T2D patients, mainly due to endothelial damage. The presence of HTGW had no significant effect on arterial stiffness compared with other T2D individuals.

Antihypertensive and Vasodilatory Effects of Qingda Granules by Suppression of Calcium Influx and the AKT Pathway

The Qingda granule (QDG) formulation was simplified from the Qingxuan Jiangya Decoction, which has been used in China to treat hypertension for decades. However, the molecular mechanisms of QDG in antihypertension remain largely unknown. Therefore, we evaluated the therapeutic efficacy of QDG against elevated blood pressure and explored its underlying mechanism. QDG treatment decreased elevated blood pressure and increased the vascular elasticity of thoracic aortic rings to KCl stimulation in spontaneously hypertensive rats. QDG treatment increased the relaxation of isolated thoracic aortic rings precontracted with norepinephrine (NE) or KCl in an endothelium-independent manner, which was attenuated by treatment with verapamil, but not by treatment with TEA, 4-AP, Gli, or BaCl2. Moreover, QDG pretreatment attenuated the CaCl2-induced constriction of isolated thoracic aortic rings in K- or NE-containing Ca-free solutions. In addition, QDG pretreatment significantly inhibited the influx of Ca in A7r5 cells induced by a K- or NE-containing Ca solution and decreased the levels of p-AKT but had no effect on levels of total AKT protein in isolated thoracic aortic rings. Considering these results, QDG treatment attenuated elevated blood pressure and promoted the vasorelaxation of thoracic aortic rings by inhibiting the influx of Ca and activating the AKT pathway.

Cocaine use modifies the association between antiretroviral therapy and endothelial dysfunction among adults with HIV infection

Cocaine is commonly used among HIV-infected people and may worsen HIV disease progression. In addition, existing evidence suggests a link between antiretroviral regimens and endothelial dysfunction. This study aimed to examine whether the associations of antiretroviral therapy (ART) regimens with endothelial dysfunction may be modified by cocaine use in adults with HIV infection. Between 2003 and 2014, 466 HIV-positive participants residing in Baltimore, Maryland, were enrolled in a study investigating comorbidities associated with HIV/ART. The associations between various risk factors and endothelial dysfunction indicators were examined by robust regression models fitted for the overall subjects and cocaine subgroups, separately. Duration of nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based therapy was negatively associated with plasma vWF:Ag levels in cocaine non-users (β = -.715, SE = .220, P < .05). However, cocaine users on longer-term NNRTI-based regimens had greater plasma endothelin-1 (ET-1) concentrations than their counterparts (β = .003, SE = .001, P < .05). In addition, current cigarette smoking was significantly positively associated with ET-1 concentrations in both cocaine non-users (β = .609, SE = .164, P < .05) and cocaine users (β = .331, SE = .086, P < .05). In conclusion, cocaine use modified the potential effects of NNRTI-based therapy on biomarkers of endothelial dysfunction. These findings suggested that reduction in cocaine use may improve endothelial function in HIV-infected cocaine users.

Demethoxycurcumin: A naturally occurring curcumin analogue for treating non-cancerous diseases

Turmeric extracts contain three primary compounds, which are commonly referred to as curcuminoids. They are curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin. While curcumin has been the most extensively studied of the curcuminoids, it suffers from low overall oral bioavailability due to extremely low absorption as a result of low water solubility and instability at acidic pH, as well as rapid metabolism and clearance from the body. However, DMC, which lacks the methoxy group on the benzene ring of the parent structure, has much greater chemical stability at physiological pH and has been recently reported to exhibit antitumor properties. However, the treatment of noncancerous diseases with DMC has not been comprehensively reviewed. Therefore, here we evaluate published scientific literature on the therapeutic properties of DMC. The beneficial pharmacological actions of DMC include anti-inflammatory, neuroprotective, antihypertensive, antimalarial, antimicrobial, antifungal, and vasodilatory properties. In addition, DMC's ability to ameliorate the effects of free radicals and an environment characterized by oxidative stress caused by the accumulation of advanced glycation end-products associated with diabetic nephropathy, as well as DMC's capacity to inhibit the migration and proliferation of vascular smooth muscle cells following balloon angioplasty are also addressed. This review collates the available literature regarding the therapeutic possibilities of DMC in noncancerous conditions.

Demethoxycurcumin Preserves Renovascular Function by Downregulating COX-2 Expression in Hypertension

Hypertension-associated endothelial dysfunction is largely due to the exaggerated vasoconstrictor generation by cyclooxygenase-2 (COX-2). COX-2 is induced under inflammatory condition. Demethoxycurcumin (DMC) is a major component of Curcuma longa L, which possesses anti-inflammatory action. This study aimed to examine whether DMC protects endothelial function in hypertension by modulating COX-2. Changes in isometric tension showed that in vivo and ex vivo treatment with DMC rescued the attenuated endothelium-dependent relaxations (EDRs) and elevated endothelium-dependent contractions (EDCs) in the renal arteries of SHR, which were also corrected by acute usage of the COX-2 inhibitor celecoxib. The restoration of renovascular activity by DMC was accompanied by the normalization of COX-2 expression. The enhanced COX-2 expression observed in the renal arteries of hypertensive patients was suppressed by incubation of excised arteries with DMC for 12 hrs. In the renal arteries of Wistar-Kyoto rats (WKY), DMC prevented the endothelial dysfunction caused by angiotensin II. The reduction in the generation of nitric oxide (NO) and expression of eNOS phosphorylation (Ser1177) in human umbilical vein endothelial cells caused by angiotensin II (Ang II) were restored by DMC or celecoxib. Our findings suggest that DMC may decrease COX-2 expression and improve endothelial function in hypertension.

Chronic exposure to biomass fuel smoke and markers of endothelial inflammation

Indoor smoke exposure may affect cardiovascular disease (CVD) risk via lung-mediated inflammation, oxidative stress, and endothelial inflammation. We sought to explore the association between indoor smoke exposure from burning biomass fuels and a selected group of markers for endothelial inflammation. We compared serum concentrations of amyloid A protein, E-selectin, soluble intercellular adhesion molecule 1 (ICAM-1) and VCAM-1, von Willebrand factor (vWF), and high-sensitivity C-reactive protein (hs-CRP) in 228 biomass-exposed vs. 228 non-exposed participants living in Puno, Peru. Average age was 56 years (s.d. = 13), average BMI was 26.5 kg/m(2) (s.d. = 4.4), 48% were male, 59.4% completed high school, and 2% reported a physician diagnosis of CVD. In unadjusted analysis, serum levels of soluble ICAM-1 (330 vs. 302 ng/ml; P < 0.001), soluble VCAM-1 (403 vs. 362 ng/ml; P < 0.001), and E-selectin (54.2 vs. 52.7 ng/ml; P = 0.05) were increased in biomass-exposed vs. non-exposed participants, respectively, whereas serum levels of vWF (1148 vs. 1311 mU/ml; P < 0.001) and hs-CRP (2.56 vs. 3.12 mg/l; P < 0.001) were decreased, respectively. In adjusted analyses, chronic exposure to biomass fuels remained positively associated with serum levels of soluble ICAM-1 (P = 0.03) and VCAM-1 (P = 0.05) and E-selectin (P = 0.05), and remained negatively associated with serum levels of vWF (P = 0.02) and hs-CRP (P < 0.001). Daily exposure to biomass fuel smoke was associated with important differences in specific biomarkers of endothelial inflammation and may help explain accelerated atherosclerosis among those who are chronically exposed.

Effect of red yeast rice combined with antioxidants on lipid pattern, hs-CRP level, and endothelial function in moderately hypercholesterolemic subjects

Our aim was to test, through a crossover, double-blind, placebo-controlled randomized clinical trial, if a short-term treatment with 10 mg monacolins combined with antioxidants could improve lipid pattern, high-sensitivity C-reactive protein (hs-CRP), and endothelial function in a small cohort of moderately hypercholesterolemic subjects. Thus, 25 healthy, moderately hypercholesterolemic subjects were consecutively enrolled and, after 4 weeks of stabilization diet, were randomized to the sequence placebo followed by a washout, monacolins or monacolins followed by a washout, placebo, with each period being 4 weeks long. At each study step, a complete lipid pattern, safety parameters, hs-CRP, and endothelial function have been measured. When compared to the placebo phase, during monacolin treatment, patients experienced a more favorable percentage change in total cholesterol (TC) (TC after monacolin treatment, −18.35%; TC after placebo treatment, −5.39%), low-density lipoprotein cholesterol (LDL-C) (LDL after monacolin treatment, −22.36%; LDL after placebo treatment, −1.38%), non-high-density lipoprotein cholesterol (HDL-C) (non-HDL after monacolin treatment, −22.83%; non-HDL after placebo treatment: −7.15%), hs-CRP (hs-CRP after monacolin treatment: −2.33%; hs-CRP after placebo treatment, 2.11%), and endothelial function (pulse volume displacement after monacolin treatment, 18.59%; pulse volume displacement after placebo treatment, −6.69%). No significant difference was observed with regard to triglycerides, HDL-cholesterol, and safety parameters. On the basis of our data, we could demonstrate that a 10 mg monacolin nutraceutical treatment appears to safely reduce cholesterolemia, hs-CRP, and markers of vascular remodeling in moderately hypercholesterolemic subjects. These results need to be confirmed in larger patient samples and in studies with longer duration.

Periodontal disease and incidence of hypertension in the health professionals follow-up study

BACKGROUND

Recent studies suggest a possible association between periodontal disease and hypertension; however, prospective evidence is limited.

METHODS

The study population consisted of 31,543 participants of the Health Professionals' Follow-Up Study (HPFS) prospective cohort who were 40-75 years old at baseline, had no prior hypertension history and had complete baseline information on oral health. Information on periodontal disease, hypertension and potential confounders was updated biennially. We used Cox proportional hazards models to study the relation between periodontal disease at baseline, during follow-up, periodontal bone loss severity, baseline number of teeth, and tooth loss during follow-up, and the risk of developing hypertension. Multivariate models included age, calendar time, race, comprehensive smoking index (CSI), diabetes, alcohol consumption, family history of hypertension, dental profession, body mass index (BMI), physical activity, fruit and vegetable intake, multivitamin use, calcium, vitamin D and vitamin E intake.

RESULTS

We identified 10,828 cases of incident hypertension over 20 years of follow-up. After adjusting for potential confounders, we did not observe significant associations between incident hypertension and periodontal disease at baseline (relative risk (RR) = 1.04; 95% confidence interval (CI): 0.98-1.10), periodontitis during follow-up (RR = 1.01; 95% CI: 0.96-1.05), tooth loss during follow-up (RR = 1.03; 95% CI: 0.98-1.09), or when comparing men with 0-10 teeth to men with ≥ 25 teeth at baseline (RR = 1.05; 95% CI: 0.91-1.21). Participants reporting severe periodontal bone loss had a RR for incident hypertension of 1.02 compared to those without bone loss (95% CI: 0.77-1.35).

CONCLUSIONS

We did not observe an association between periodontal disease measures and incident hypertension in this cohort of middle-aged men.

Antihyperlipidemic agents cause a decrease in von Willebrand factor levels in pediatric patients with familial hyperlipidemia

Familial hyperlipidemia is a group of genetic disorders with a predisposition to atherosclerosis. Hyperlipidemia causes increased atherosclerotic events through increased endothelial damage. In this report we aimed to measure the plasma fibrinogen and von Willebrand factor antigen (VWf:Ag) levels in pediatric patients with familial hyperlipidemias and to investigate the effects of serum lipid levels and antihyperlipidemic agents on these parameters. Of the 41 patients analyzed, vWf:Ag level was significantly lower in antihyperlipidemic receivers (132 +/- 51%, 102 +/- 19%; p = 0.010). This finding may indicate that early initiation of antihyperlipidemics in patients with familial hyperlipidemias may decrease the risk of future atherosclerotic events through not only decreasing the serum lipid levels, but also decreasing plasma vWf:Ag levels.

Plasma levels of von Willebrand factor are increased in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterised by inappropriate hypertrophy, small-vessel coronary artery disease, myocyte disarray and increased interstitial fibrosis. Microvascular dysfunction is a common finding in HCM and its extent has been proposed as an important prognostic marker. Plasma von Willebrand factor (vWf) is an established marker of endothelial damage or dysfunction; however it has scarcely been studied in HCM. We hypothesised that vWf could be raised in patients with HCM and be related to different variables associated with severity of HCM.

METHODS

We included 124 HCM patients, 93 males, aged 48+/-15 years, 59 healthy control subjects with similar age and sex and 20 patients with ischemic heart disease but clinical stability for the last 6 months. A complete history and clinical examination was performed, including 12-lead electrocardiogram, echocardiography, 24 hours ECG-Holter monitoring, and symptom limited treadmill exercise test. Risk factors for sudden death were evaluated. A blinded cardiac MRI was performed with late enhanced study with Gadolinium. Plasma vWf levels were assayed by commercial ELISA.

RESULTS

Patients showed higher levels of vWf (140.0+/-65.0 UI/ml vs 105.0+/-51.0 UI/ml, p<0.001) even after adjusting for ABO blood group. vWf levels were found raised in patients with severe functional class (168.4+/-65.9 UI/mL vs 132.4+/-60.7 UI/mL, p=0.020), atrial fibrillation (175.8+/-69.4 UI/mL vs 133.0+/-59.0 UI/mL, p=0.005), hypertension (161.4+/-60.8 vs 128.9+/-60.5, p=0.010) obstruction (153.9+/-67.9 vs 128.2+/-57.4 UI/mL, p=0.046) and non sustained ventricular tachycardia (159.3+/-59.1 vs 133.0+/-63.0, p=0.049). vWf correlated with age (r:0.26; p=0.006) and obstruction (r:0.22; p=0.021).

CONCLUSIONS

We show, for the first time, patients with HCM present significantly raised levels of vWf. These are associated with different conditions related to the severity of the disease.

Akt-mediated transactivation of the S1P1 receptor in caveolin-enriched microdomains regulates endothelial barrier enhancement by oxidized phospholipids

Endothelial cell (EC) barrier dysfunction results in increased vascular permeability, leading to increased mass transport across the vessel wall and leukocyte extravasation, the key mechanisms in pathogenesis of tissue inflammation and edema. We have previously demonstrated that OxPAPC (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine) significantly enhances vascular endothelial barrier properties in vitro and in vivo and attenuates endothelial hyperpermeability induced by inflammatory and edemagenic agents via Rac and Cdc42 GTPase dependent mechanisms. These findings suggested potential important therapeutic value of barrier-protective oxidized phospholipids. In this study, we examined involvement of signaling complexes associated with caveolin-enriched microdomains (CEMs) in barrier-protective responses of human pulmonary ECs to OxPAPC. Immunoblotting from OxPAPC-treated ECs revealed OxPAPC-mediated rapid recruitment (5 minutes) to CEMs of the sphingosine 1-phosphate receptor (S1P(1)), the serine/threonine kinase Akt, and the Rac1 guanine nucleotide exchange factor Tiam1 and phosphorylation of caveolin-1, indicative of signaling activation in CEMs. Abolishing CEM formation (methyl-beta-cyclodextrin) blocked OxPAPC-mediated Rac1 activation, cytoskeletal reorganization, and EC barrier enhancement. Silencing (small interfering RNA) Akt expression blocked OxPAPC-mediated S1P(1) activation (threonine phosphorylation), whereas silencing S1P(1) receptor expression blocked OxPAPC-mediated Tiam1 recruitment to CEMs, Rac1 activation, and EC barrier enhancement. To confirm our in vitro results in an in vivo murine model of acute lung injury with pulmonary vascular hyperpermeability, we observed that selective lung silencing of caveolin-1 or S1P(1) receptor expression blocked OxPAPC-mediated protection from ventilator-induced lung injury. Taken together, these results suggest Akt-dependent transactivation of S1P(1) within CEMs is important for OxPAPC-mediated cortical actin rearrangement and EC barrier protection.

von Willebrand factor, C-reactive protein, nitric oxide, and vascular endothelial growth factor in a dietary reversal model of hypercholesterolemia in rabbit

AIMS

Endothelial dysfunction is considered a sign of the early vascular changes preceding atherosclerosis. We studied the alteration of von Willebrand Factor (vWF), C - reactive protein (CRP), nitrite and Vascular Endothelial Growth Factor (VEGF) in a dietary reversal model of hypercholesterolemia in rabbit.

METHODS

This project was designed in two phases. In phase I, male rabbits (n = 11) were fed a 1% high cholesterol diet for 30 days. Then the diet was replaced with normal rabbit chow for other 30 days (cholesterol withdrawal phase, phase II). To compare the fatty streak formation with normal condition, a control group (n = 6) received normal diet during the study. The serum lipid levels, vWF, CRP, nitrite, and VEGF were measured before the experiment and by the end of each phase. Fatty streak formation in the walls of the aortas in both groups (high cholesterol diet and control group) was determined using intima thickness/media thickness (IMT) ratio.

RESULTS

The results indicate that the level of cholesterol, Low Density Lipoproteins (LDL), vWF and CRP increased significantly in phase I, and decreased after hypercholesterolemic diet withdrawal (p < 0.05). No statistically significant changes were found in VEGF levels but the serum level of nitrite increased significantly during both phases of the study (p < 0.05). The IMT ratio in the walls of aortas was significantly different between the groups in both phases of studies (p < 0.05). There was a significant correlation between nitrite and cholesterol levels in both phases (r = 0.62 and r = 0.98, p < 0.05). Nitrite concentration also correlated with IMT ratio in both phases of the study (r = 0.75 and r = -0.99, p < 0.05). vWF did not correlate with cholesterol but it correlated with IMT ratio in both phases of the study (r = 0.87 and r = 0.84, p < 0.05). CRP only correlated with cholesterol in the first phase (r = 0.91, p < 0.05).

CONCLUSIONS

Among the endothelial biomarkers, vWF was found to be a biological marker for identifying the risk of developing atherosclerosis; however a single biomarker may not provide appropriate information.

Cardiac cachexia: a systematic overview

Cardiac cachexia as a terminal stage of chronic heart failure carries a poor prognosis. The definition of this clinical syndrome has been a matter of debate in recent years. This review describes the ongoing discussion about this issue and the complex pathophysiology of cardiac cachexia and chronic heart failure with particular focus on immunological, metabolic, and hormonal aspects at the intracellular and extracellular level. These include regulators such as neuropeptide Y, leptin, melanocortins, ghrelin, growth hormone, and insulin. The regulation of feeding is discussed as are nutritional aspects in the treatment of the disease. The mechanisms of wasting in different body compartments are described. Moreover, we discuss several therapeutic approaches. These include appetite stimulants like megestrol acetate, medroxyprogesterone acetate, and cannabinoids. Other drug classes of interest comprise angiotensin-converting enzyme inhibitors, beta-blockers, anabolic steroids, beta-adrenergic agonists, anti-inflammatory substances, statins, thalidomide, proteasome inhibitors, and pentoxifylline.

A relationship between insulin sensitivity and vasodilation in women with a history of preeclamptic pregnancy

Women with a history of preeclampsia are characterized by vascular dysfunction and an increased risk of cardiovascular disease. In the present study we investigated whether insulin sensitivity is decreased in women with previous preeclampsia and whether it is associated with endothelium-dependent and/or -independent vasodilation and/or features of metabolic syndrome. Twenty-eight nonobese women with previous severe preeclampsia and 20 women with a previous normotensive pregnancy were studied 5 to 6 years after the index pregnancy. Vasodilation was measured by venous occlusion plethysmography after intra-arterial infusions of sodium nitroprusside and acetylcholine and insulin sensitivity by the intravenous glucose tolerance test using the minimal model technique. The women were tested for lipid profile, inflammatory status and endothelial activation. Insulin sensitivity did not differ between the groups (P=0.24). Insulin sensitivity correlated positively to endothelium-dependent vasodilation only in the patient group in both low (beta=0.59; P=0.04) and high (beta=0.53; P=0.04) concentrations of acetylcholine and in a high concentration of sodium nitroprusside (beta=0.0007; P=0.006). In multivariate analysis, the waist/hip ratio (P=0.04) and serum triglycerides (P=0.04) had the most effect on insulin sensitivity in the patient group. Gestational weeks at the onset of preeclamptic hypertension (P=0.02) and proteinuria (P=0.02) associated positively with insulin sensitivity together with first-trimester body mass index (P=0.008) and maximum diastolic blood pressure during preeclampsia (P=0.005). The present study indicates a relation between insulin sensitivity with vascular dilatory function in women with previous preeclampsia. Furthermore, early onset preeclampsia correlates with impaired insulin sensitivity later in life.

Orthostatic hypercoagulability: a novel physiological mechanism to activate the coagulation system

Orthostatic stress causes significant plasma shift and raises transmural pressure in lower extremities, resulting in an increase in endothelial activation and plasma proteins concentrations, possibly including coagulation factors. This may lead to activation of the coagulation system during standing. To test this hypothesis, we recruited 18 healthy volunteers (9 females and 9 males; mean age: 25+/-1.2 years; body mass index: 21.7+/-0.5 kg/m(2)). Hemodynamics, plasma shift (extrapolated from sequential hematocrit concentration), plasma proteins, and coagulation tests, including procoagulants; fibrinogen, factor V, and factor VIII activity; prothrombin fragments 1 and 2; and endothelial activation-related factors (tissue factor and von Willebrand factor), as well as protein C global pathway, were determined at rest supine and at 15 minutes, 30 minutes, and 60 minutes of still standing. Thirty minutes of standing caused a decrease in plasma volume by 12.0+/-0.5% and an increase in plasma protein by 13.0+/-0.7%. Fibrinogen, factor V, and factor VIII activity rose by 12.0+/-1.2%, 13.0+/-1.0%, and 40.0+/-6.0% (P<0.002 for all), respectively. Prothrombin fragments 1 and 2 were elevated by 150.0+/-30.0%. Tissue factor and von Willebrand factor increased by 30.0+/-9.0% and 17.4+/-51.0% (P<0.02 for both), respectively. However, protein C assay results decreased from 0.95+/-0.20 to 0.83+/-0.16 (P<0.001). We hereby introduce a novel physiological mechanism, "orthostatic procoagulation," that should be considered during coagulation tests. Furthermore, it could be extrapolated to the pathophysiology of stasis and venous thromboembolism.

Chronically impaired endothelial vasoreactivity following oversized endovascular introducer sheath placement in porcine iliac arteries: implications for endovascular therapy

The conventional endovascular aortic aneurysm procedure entails the placement of oversized introducer sheaths in relatively normal ileofemoral arteries to allow the delivery and deployment of endovascular prosthesis. Endoluminal manipulation with passage of oversized endoluminal devices can lead to endothelial denudation, resulting in impaired cellular function. The purpose of this study was to assess the time course of endothelial function with vasoreactivity following oversized endovascular sheath insertion ranging from 1 day to 16 weeks in normal porcine iliac arteries. Following oversized introducer sheath placement in bilateral iliac arteries, vasoreactivity was tested using both endothelium-dependent and -independent vasodilators. Intravascular ultrasonography showed a significant reduction in the luminal area at 12 and 16 weeks. This was similarly supported by morphometric analysis, which showed increased medial thickness with an elevated intima to media ratio at the same time course. Endothelium-dependent relaxation to bradykinin, calcium ionophore A23187, serotonin, and adenosine diphosphate all uniformly displayed attenuated endothelial dysfunction at all time points when compared with the control group. In contrast, endothelium-independent relaxation showed a decreased vasoresponsiveness at 4 weeks. In conclusion, this study underscored the detrimental and chronic endothelial dysfunction in a normal artery caused by oversized introducer sheath placement. Chronically impaired endothelial function may play a role leading to iliofemoral artery thrombosis or late occlusion, which were well-recognized adverse events following endovascular aneurysm procedures. Our study underscores the importance of appropriate patient selection to minimize potential sheath oversize and endograft device miniaturization to avoid vessel wall injury and maintain vasoreactivity.

Soluble E-selectin, von Willebrand factor, soluble thrombomodulin, and total body nitrate/nitrite product as indices of endothelial damage/dysfunction in paroxysmal, persistent, and permanent atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with a prothrombotic state, which is related to endothelial damage/dysfunction. Plasma levels of soluble E-selectin (sE-sel), von Willebrand factor (vWf), and soluble thrombomodulin (sTM) have been used as indexes of endothelial activation, damage/dysfunction, and endothelial damage, respectively. Nitric oxide is also made by a healthy endothelium, and a total body nitrate/nitrite product (NOx) is used as a measure of endothelial nitric oxide production. We hypothesized that the levels of these markers of endothelial function would be abnormal in patients with paroxysmal, persistent, and permanent AF.

METHODS

We studied 145 AF patients (paroxysmal AF, 35 patients; permanent AF, 50 patients; persistent AF, 60 patients) and 35 patients with "lone" AF. Plasma levels of sE-sel, vWf, and sTM (measured by enzyme-linked immunosorbent assay) and NOx (measured by a colorimetric assay based on the Griess reaction) were compared to 40 age-matched healthy control subjects in sinus rhythm.

RESULTS

Patients with AF had significantly higher plasma levels of vWf (p < 0.001) and sE-sel (p = 0.005) compared with control subjects, but sTM and NOx levels were not significantly different. Levels did not differ significantly among the clinical subgroups of patients with paroxysmal, persistent, and permanent AF. Patients with lone AF had significantly higher vWF levels (p = 0.003) and significantly lower sTM levels (p = 0.0361) compared to control subjects, but sE-sel and NOx levels were not significantly different. There were no significant differences in the AF study population in vWF, sE-sel or sTM levels after 4 weeks of warfarin treatment.

CONCLUSION

Endothelial perturbation exists in all clinical subgroups of patients with AF, including those with lone AF, which may contribute to the prothrombotic state seen in these patients.

A long-term "memory" of HIF induction in response to chronic mild decreased oxygen after oxygen normalization

Background

Endothelial dysfunction (ED) is functionally characterized by decreased vasorelaxation, increased thrombosis, increased inflammation, and altered angiogenic potential, has been intimately associated with the progression and severity of cardiovascular disease. Patients with compromised cardiac function oftentimes have a state of chronic mild decreased oxygen at the level of the vasculature and organs, which has been shown to exacerbate ED. Hypoxia inducible factor (HIF) is a transcription factor complex shown to be the master regulator of the cellular response to decreased oxygen levels and many HIF target genes have been shown to be associated with ED.

Methods

Human endothelial and aortic smooth muscle cells were exposed either to A) normoxia (21% O₂) for three weeks, or to B) mild decreased oxygen (15% O₂) for three weeks to mimic blood oxygen levels in patients with heart failure, or to C) mild decreased oxygen for two weeks followed by one week of normoxia ("memory" treatment). Levels of HIF signaling genes (HIF-1α, HIF-2α, VEGF, BNIP3, GLUT-1, PAI-1 and iNOS) were measured both at the protein and mRNA levels.

Results

It was found that chronic exposure to mild decreased oxygen resulted in significantly increased HIF signaling. There was also a "memory" of HIF-1α and HIF target gene induction when oxygen levels were normalized for one week, and this "memory" could be interrupted by adding a small molecule HIF inhibitor to the last week of normalized oxygen. Finally, levels of ubiquitylated HIF-1α were reduced in response to chronic mild decreased oxygen and were not full restored after oxygen normalization.

Conclusion

These data suggest that HIF signaling may be contributing to the pathogenesis of endothelial dysfunction and that normalization of oxygen levels may not be enough to reduce vascular stress.

Involvement of endothelial cell-derived CGRP in heat stress-induced protection of endothelial function

Previous studies have shown that heat stress possesses cardioprotection, which is related to the synthesis and release of calcitonin gene-related peptide (CGRP) via activation of capsaicin receptor (vanilloid receptor subtype 1, VR1) on the capsaicin-sensitive sensory neurons. The VR1 exists in human umbilical vein endothelial cells (HUVECs). Endothelial cells can synthesize CGRP and CGRP could protect against endothelial dysfunction induced by lysophosphatidylcholine (LPC) or oxidized low-density lipoprotein. In the present study, we explored whether the endothelial cell-derived CGRP is involved in the effect of heat stress on endothelial function in vivo and in vitro. Our results indicated that heat stress significantly increased the plasma concentration of CGRP, which was abolished by pretreatment with capsazepine, a VR1 antagonist. Immunohistochemistry and in situ hybridization showed that the endothelium of mesenteric artery and aorta expressed CGRP. And heat stress increased the expression of CGRP, which was also abolished by capsazepine. LPC attenuated the endothelium-dependent relaxation responses of aorta rings, which were improved by pretreatment with heat stress. In cultured HUVECs, the CGRP secretion was increased after heat stress. LPC increased the lactate dehydrogenase (LDH) activity in the cultured medium and decreased the cell viability, suggesting that LPC injured the HUVECs. However, pretreatment with heat stress attenuated the injurious effects of LPC on HUVECs. And this beneficial effect of heat stress on HUVECs was inhibited by capsazepine or CGRP(8-37), the CGRP receptor antagonist. The present results suggest that the endothelial cell-derived CGRP contributes to the protective effects of heat stress on endothelial function. Our study provides a potential mechanism to explain the protective effect of heat stress on cardiovascular system.