Irisin relaxes mouse mesenteric arteries through endothelium-dependent and endothelium-independent mechanisms

Irisin, a newly discovered myokine, has been shown to produce modest weight loss and improve glucose intolerance in mice. The purpose of this study was to investigate the effects of irisin on vascular activity and the mechanisms involved. Experiments were performed on mouse mesenteric arteries. We demonstrated that irisin induced relaxation in mesenteric arteries with or without endothelium in a concentration-dependent manner. It was further demonstrated that the irisin-induced vasorelaxation effects on endothelium-intact mesenteric arteries were reduced by pretreatment with Nω-nitro-L-arginine methyl ester (L-NAME) or 1H-[1, 2, 4] oxadizolo [4, 3-a] quinoxalin-1-one (ODQ). However, pretreatment with indomethacin (INDO), a nonselective cyclooxygenase inhibitor did not modulate irisin-induced relaxation. In addition, the contraction due to extracellular Ca(2+) influx and intracellular Ca(2+) release was also inhibited by irisin. In summary, these results suggested that the endothelium-dependent relaxation of irisin is mediated by the nitric oxide (NO)-guanosine 3', 5'-cyclic phosphate (cGMP)-dependent pathway but not the prostaglandin I2 (PGI2)-cyclic adenosine monophosphate (cAMP)-dependent mechanism. Endothelium-independent relaxation may be depend on inhibiting Ca(2+) influx through blocking VDCCs and intracellular Ca(2+) release through both IP3R and RyR channels.

[Stiffness of the Arterial Wall and Central Hemodynamics During Long-Term Combination Antihypertensive Therapy]

Aim of the METR study - to assess effect of antihypertensive therapy with fixed combination of angiotensin converting enzyme inhibitor lisinopril (10 mg) and calcium antagonist amlodipine (5 mg) on parameters of arterial wall stiffness and central hemodynamics in patients with stage I-II essential hypertension (EH) and functional class II-III ischemic heart disease. Combination therapy was associated with persistent lowering of central arterial pressure, decrease of augmentation index and other parameters of arterial wall stiffness, and reduction of left ventricular myocardial mass. These changes have a potential to lower risk of cardiovascular complications and improve prognosis of patients with EH.

Impact of Hydroxychloroquine on Atherosclerosis and Vascular Stiffness in the Presence of Chronic Kidney Disease

Cardiovascular disease is the largest cause of morbidity and mortality among patients with chronic kidney disease (CKD) and end-stage kidney disease, with nearly half of all deaths attributed to cardiovascular disease. Hydroxychloroquine (HCQ), an anti-inflammatory drug, has been shown to have multiple pleiotropic actions relevant to atherosclerosis. We conducted a proof-of-efficacy study to evaluate the effects of hydroxychloroquine in an animal model of atherosclerosis in ApoE knockout mice with and without chronic kidney disease. Forty male, 6-week-old mice were divided into four groups in a 2 x 2 design: sham placebo group; sham treatment group; CKD placebo group; and CKD treatment group. CKD was induced by a two-step surgical procedure. All mice received a high-fat diet through the study duration and were sacrificed after 16 weeks of therapy. Mice were monitored with ante-mortem ultrasonic echography (AUE) for atherosclerosis and vascular stiffness and with post-mortem histology studies for atherosclerosis. Therapy with HCQ significantly reduced the severity of atherosclerosis in CKD mice and sham treated mice. HCQ reduced the area of aortic atherosclerosis on en face examination by approximately 60% in HCQ treated groups compared to the non-treated groups. Additionally, therapy with HCQ resulted in significant reduction in vascular endothelial dysfunction with improvement in vascular elasticity and flow patterns and better-preserved vascular wall thickness across multiple vascular beds. More importantly, we found that presence of CKD had no mitigating effect on HCQ's anti-atherosclerotic and vasculoprotective effects. These beneficial effects were not due to any significant effect of HCQ on inflammation, renal function, or lipid profile at the end of 16 weeks of therapy. This study, which demonstrates structural and functional protection against atherosclerosis by HCQ, provides a rationale to evaluate its use in CKD patients. Further studies are needed to define the exact mechanisms through which HCQ confers these benefits.

Relative Importance of Aortic Stiffness and Volume as Predictors of Treatment-Induced Improvement in Left Ventricular Mass Index in Dialysis

This study aimed to explore the relative contribution of aortic stiffness and volume in treatment-induced change of left ventricular mass in dialysis. Hypertension in Hemodialysis Patients Treated with Atenolol or Lisinopril trial compared the effect of lisinopril versus atenolol in reducing left ventricular mass index; 179 patients with echo measurements of aortic pulse wave velocity and left ventricular mass at baseline were included. In unadjusted analysis, overall reductions of 26.24 g/m² (95% CI: -49.20, -3.29) and 35.67 g/m² (95% CI: -63.70, -7.64) in left ventricular mass index were noted from baseline to 6 and 12 months respectively. Volume control emerged as an important determinant of regression of left ventricular mass index due to the following reasons: (i) additional control for change in ambulatory systolic blood pressure mitigated the reduction in left ventricular mass index in the statistical model above [6-month visit: -18.6 g/m² (95% CI: -43.7, 6.5); 12-month visit: -22.1 g/m² (95% CI: -52.2, 8.0)] (ii) regression of left ventricular hypertrophy was primarily due to reduction in left ventricular chamber and not wall thickness and (iii) adjustment for inferior vena cava diameter (as a proxy for volume) removed the effect of time on left ventricular mass index reduction [6-month visit: -6.6 g/m² (95% CI: (-41.6, 28.4); 12-month visit: 0.6 g/m² (95% CI: -39.5, 40.7)]. In contrast, aortic pulse wave velocity was neither a determinant of baseline left ventricular mass index nor predictor of its reduction. Among dialysis patients, ambulatory systolic pressure, a proxy for volume expansion, but not aortic stiffness is more important predictor of reduction in left ventricular mass index. Improving blood pressure control via adequate volume management appears as an effective strategy to improve left ventricular hypertrophy in dialysis.

Silencing of activin receptor-like kinase 7 alleviates aortic stiffness in type 2 diabetic rats

AIM

Arterial stiffness is an important feature of diabetic macrovascular complications. Activin receptor-like kinase 7 (ALK7), a member of type I transforming growth factor-β (TGF-β) receptors, is correlated with pathogenic risks of type 2 diabetes mellitus and cardiovascular diseases and may be involved in cardiovascular remodeling. We aimed to investigate whether ALK7 is implicated in diabetes-induced aortic stiffness.

METHODS

Type 2 diabetes was induced by high-fat diet and low-dose streptozotocin (STZ; 27.5 mg/kg). Forty rats were separated into four groups: control, diabetes, diabetes with empty virus and diabetes treated with ALK7-shRNA. The metabolic index, ALK 7 expression and aortic stiffness were evaluated. We used gene silencing method to investigate the role of ALK7 in the pathological development.

RESULTS

Diabetic rats showed increased blood glucose, cholesterol, triglyceride levels, severe insulin resistance and ALK7 overexpression. Diabetes enhanced aortic stiffness, as demonstrated by the loss and disruption of elastic fibers as well as by an increase in collagen fibers in the aortic media. ALK7 gene silencing ameliorated metabolic hyperlipidemia and insulin resistance. With ALK7 gene silencing, collagen content, elastin to collagen ratio, as well as collagen I-to-collagen III content ratio in diabetic rats were significantly decreased. Moreover, the phosphorylation level of Smad2/3 was markedly decreased after ALK7 gene silencing.

CONCLUSIONS

ALK7 gene silencing has a protective effect on diabetes-induced aortic stiffness, insulin resistance and hyperlipidemia, thus implicating a new potential therapeutic approach to diabetic macrovascular stiffness.

DPP-4 Inhibitor Reduces Central Blood Pressure in a Diabetic and Hypertensive Patient: A Case Report

Hypertension and type 2 diabetes mellitus (DM) are among the main risk factors for the development of cardiovascular disease. Pharmacotherapy for DM should not only improve blood glucose control, but also provide beneficial glucose-independent cardiovascular effects. The central systolic blood pressure (SBP) has become more important than the brachial SBP in the assessment of cardiovascular risk.This case report describes the effect of vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, on the central SBP in a 54-year-old woman with hypertension and DM. She was submitted to applanation tonometry (AT) before and after vildagliptin association. AT of the radial artery is a non-invasive method that indirectly assesses arterial stiffness by calculating the central SBP and the augmentation index (AIx).After 3 months of follow-up using vildagliptin, central SBP and AIx were improved. Moreover, she presented better glycemic control.This case suggests an effect of DPP-4 inhibitor on arterial stiffness parameter (central SBP) in a hypertensive and diabetic patient, which shows a glucose-independent beneficial cardiovascular effect of this group of drugs.

Effects of Celiprolol and Bisoprolol on Blood Pressure, Vascular Stiffness, and Baroreflex Sensitivity

BACKGROUND

We tested the hypothesis that celiprolol and bisoprolol have differential effects on blood pressure (BP), flow-mediated dilation (FMD), and vascular stiffness.

METHODS

We analyzed 102 hypertensives (mean age: 59±14 years) who were being treated other than beta-blockers. They were randomized to receive add-on treatment with either celiprolol 100-200mg (C group) or bisoprolol 2.5-5mg (B group), and followed up for 3 months. In addition to clinic, home, and ambulatory BP monitoring, the FMD, radial augmentation index (AI), brachial-ankle pulse wave velocity (baPWV), urine albumin-to-creatinine ratio, and baroreflex sensitivity (BRS) were measured at baseline and at the end of the study.

RESULTS

Compared to the baseline values, home and 24-hour BP were significantly lowered in the third month in both groups (all Ps < 0.05). Pulse rate (PR) and baPWV were reduced (P < 0.001), and BRS was increased significantly only in the B group (P = 0.02). Radial AI was unchanged in the C group but was significantly increased in the B group (P < 0.001). Central BP was significantly reduced in the C group (P = 0.003) but was unchanged in the B group. FMD was significantly increased in both groups (both P < 0.01).

CONCLUSION

Bisoprolol achieved the greater reduction of PR and improved BRS and vascular stiffness, whereas, celiprolol reduced the central BP level. In treated hypertensive patients, add-on use of celiprolol may be favorable in uncomplicated stage of hypertension. On the other hand, bisoprolol may be useful in hypertensives with cardiac or vascular diseases who have advanced atherosclerotic changes and sympathetic nervous system activation.

Impact of cocoa flavanol intake on age-dependent vascular stiffness in healthy men: a randomized, controlled, double-masked trial

Increased vascular stiffness, endothelial dysfunction, and isolated systolic hypertension are hallmarks of vascular aging. Regular cocoa flavanol (CF) intake can improve vascular function in healthy young and elderly at-risk individuals. However, the mechanisms underlying CF bioactivity remain largely unknown. We investigated the effects of CF intake on cardiovascular function in healthy young and elderly individuals without history, signs, or symptoms of cardiovascular disease by applying particular focus on functional endpoints relevant to cardiovascular aging. In a randomized, controlled, double-masked, parallel-group dietary intervention trial, 22 young (<35 years) and 20 elderly (50-80 year) healthy, male non-smokers consumed either a CF-containing drink (450 mg CF) or nutrient-matched, CF-free control drink bi-daily for 14 days. The primary endpoint was endothelial function as measured by flow-mediated vasodilation (FMD). Secondary endpoints included cardiac output, vascular stiffness, conductance of conduit and resistance arteries, and perfusion in the microcirculation. Following 2 weeks of CF intake, FMD improved in young (6.1 ± 0.7 vs. 7.6 ± 0.7 %, p < 0.001) and elderly (4.9 ± 0.6 vs. 6.3 ± 0.9 %, p < 0.001). Secondary outcomes demonstrated in both groups that CF intake decreased pulse wave velocity and lowered total peripheral resistance, and increased arteriolar and microvascular vasodilator capacity, red cell deformability, and diastolic blood pressure, while cardiac output remained affected. In the elderly, baseline systolic blood pressure was elevated, driven by an arterial-stiffness-related augmentation. CF intake decreased aortic augmentation index (-9 %) and thus systolic blood pressure (-7 mmHg; Clinicaltrials.gov: NCT01639781). CF intake reverses age-related burden of cardiovascular risk in healthy elderly, highlighting the potential of dietary flavanols to maintain cardiovascular health.

Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial

Observational data suggest a link between menaquinone (MK, vitamin K2) intake and cardiovascular (CV) health. However, MK intervention trials with vascular endpoints are lacking. We investigated long-term effects of MK-7 (180 µg MenaQ7/day) supplementation on arterial stiffness in a double-blind, placebo-controlled trial. Healthy postmenopausal women (n=244) received either placebo (n=124) or MK-7 (n=120) for three years. Indices of local carotid stiffness (intima-media thickness IMT, Diameter end-diastole and Distension) were measured by echotracking. Regional aortic stiffness (carotid-femoral and carotid-radial Pulse Wave Velocity, cfPWV and crPWV, respectively) was measured using mechanotransducers. Circulating desphospho-uncarboxylated matrix Gla-protein (dp-ucMGP) as well as acute phase markers Interleukin-6 (IL-6), high-sensitive C-reactive protein (hsCRP), tumour necrosis factor-α (TNF-α) and markers for endothelial dysfunction Vascular Cell Adhesion Molecule (VCAM), E-selectin, and Advanced Glycation Endproducts (AGEs) were measured. At baseline dp-ucMGP was associated with IMT, Diameter, cfPWV and with the mean z-scores of acute phase markers (APMscore) and of markers for endothelial dysfunction (EDFscore). After three year MK-7 supplementation cfPWV and the Stiffness Index βsignificantly decreased in the total group, whereas distension, compliance, distensibility, Young's Modulus, and the local carotid PWV (cPWV) improved in women having a baseline Stiffness Index β above the median of 10.8. MK-7 decreased dp-ucMGP by 50 % compared to placebo, but did not influence the markers for acute phase and endothelial dysfunction. In conclusion, long-term use of MK-7 supplements improves arterial stiffness in healthy postmenopausal women, especially in women having a high arterial stiffness.

Oral nitrite therapy improves vascular function in diabetic mice

AIM

We tested the hypothesis that short-term oral sodium nitrite supplementation would improve vascular dysfunction in obese, diabetic mice.

METHODS AND RESULTS

Vascular function was determined in control mice and in db/db mice receiving drinking water with or without sodium nitrite (50 mg/L) for 5 weeks. Nitrite supplementation increased plasma nitrite concentrations in db/db mice (0.19±0.02 µM vs 0.80±0.26 µM; p < 0.05). Db/db mice had lower endothelium-dependent dilation (EDD) in response to increasing doses of acetylcholine versus heterozygous control mice (71.2% ± 14.3% vs 93% ± 7.0%; p < 0.05), and sodium nitrite supplementation restored endothelium-dependent dilation to control levels (92.9% ± 2.3% vs 93% ± 7.0%; p < 0.05). The improvement in endothelial function was accompanied by a reduction in intrinsic stiffness, but not by alterations in plasma or vascular markers of inflammation.

CONCLUSION

These data suggest that sodium nitrite may be a novel therapy for treating diabetes-related vascular dysfunction; however, the mechanisms of improvement are unknown.

Effect of lysyl oxidase inhibition on angiotensin II-induced arterial hypertension, remodeling, and stiffness

It is well accepted that angiotensin II (Ang II) induces altered vascular stiffness through responses including both structural and material remodeling. Concurrent with remodeling is the induction of the enzyme lysyl oxidase (LOX) through which ECM proteins are cross-linked. The study objective was to determine the effect of LOX mediated cross-linking on vascular mechanical properties. Three-month old mice were chronically treated with Ang II with or without the LOX blocker, β -aminopropionitrile (BAPN), for 14 days. Pulse wave velocity (PWV) from Doppler measurements of the aortic flow wave was used to quantify in vivo vascular stiffness in terms of an effective Young’s modulus. The increase in effective Young’s modulus with Ang II administration was abolished with the addition of BAPN, suggesting that the material properties are a major controlling element in vascular stiffness. BAPN inhibited the Ang II induced collagen cross-link formation by 2-fold and PWV by 44% (P<0.05). Consistent with this observation, morphometric analysis showed that BAPN did not affect the Ang II mediated increase in medial thickness but significantly reduced the adventitial thickness. Since the hypertensive state contributes to the measured in vivo PWV stiffness, we removed the Ang II infusion pumps on Day 14 and achieved normal arterial blood pressures. With pump removal we observed a decrease of the PWV in the Ang II group to 25% above that of the control values (P=0.002), with a complete return to control values in the Ang II plus BAPN group. In conclusion, we have shown that the increase in vascular stiffness with 14 day Ang II administration results from a combination of hypertension-induced wall strain, adventitial wall thickening and Ang II mediated LOX ECM cross-linking, which is a major material source of vascular stiffening, and that the increased PWV was significantly inhibited with co-administration of BAPN.

Tetrahydrobiopterin lowers muscle sympathetic nerve activity and improves augmentation index in patients with chronic kidney disease

Chronic kidney disease (CKD) is characterized by overactivation of the sympathetic nervous system (SNS) that contributes to cardiovascular risk. Decreased nitric oxide (NO) bioavailability is a major factor contributing to SNS overactivity in CKD, since reduced neuronal NO leads to increased central SNS activity. Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase that increases NO bioavailability in experimental models of CKD. We conducted a randomized, double-blinded, placebo-controlled trial testing the benefits of oral sapropterin dihydrochloride (6R-BH4, a synthetic form of BH4) in CKD. 36 patients with CKD and hypertension were randomized to 12 wk of 1) 200 mg 6R-BH4 twice daily + 1 mg folic acid once daily; vs. 2) placebo + folic acid. The primary endpoint was a change in resting muscle sympathetic nerve activity (MSNA). Secondary endpoints included arterial stiffness using pulse wave velocity (PWV) and augmentation index (AIx), endothelial function using brachial artery flow-mediated dilation and endothelial progenitor cells, endothelium-independent vasodilatation (EID), microalbuminuria, and blood pressure. We observed a significant reduction in MSNA after 12 wk of 6R-BH4 (-7.5 ± 2.1 bursts/min vs. +3.2 ± 1.3 bursts/min; P = 0.003). We also observed a significant improvement in AIx (by -5.8 ± 2.0% vs. +1.8 ± 1.7 in the placebo group, P = 0.007). EID increased significantly (by +2.0 ± 0.59%; P = 0.004) in the 6R-BH4 group, but there was no change in endothelial function. There was a trend toward a reduction in diastolic blood pressure by -4 ± 3 mmHg at 12 wk with 6R-BH4 (P = 0.055). 6R-BH4 treatment may have beneficial effects on SNS activity and central pulse wave reflections in hypertensive patients with CKD.

Aortic stiffness and left ventricular function in patients with differentiated thyroid cancer

OBJECTIVE

The aim of this study was to investigate aortic stiffness and left ventricular (LV) systolic and diastolic function in patients with differentiated thyroid cancer (DTC) on thyroxine (L-T4) therapy and after L-T4 withdrawal to assess the cardiovascular impact of long-term subclinical hyperthyroidism and short-term overt hypothyroidism.

METHODS

Twenty-four patients who had had total thyroidectomy and radioiodine ablation for differentiated thyroid cancer were studied on two occasions: on TSH suppressive L-T4 therapy (sTSH 0.24 ± 0.11 mU/L), and 4 weeks after L-T4 withdrawal (sTSH 89.82 ± 29.36 mU/L). Echocardiography was performed and thyroid function, serum thyroglobulin, lipid parameters, homocystine, C-reactive protein, fibrinogen and von Willebrand factor activity (vWF) were measured. Twenty-two healthy volunteers matched for age and sex served as euthyroid controls.

RESULTS

Aortic stiffness was increased both in hypothyroidism (6.04 ± 2.88 cm(2)/dyn/10(3), p < 0.05) and subclinical hyperthyroidism (9.27 ± 4.81 cm(2)/dyn/10(3), p < 0.05) vs. controls (3.92 ± 1.84 cm(2)/dyn/10(3)). Subclinical hyperthyroidism had a more marked effect (p < 0.05). LV dimensions and ejection fractions were similar before and after L-T4 withdrawal. The E'/A' was higher in euthyroid controls (1.34 ± 1.02) as compared to both subclinical hyperthyroidism (1.0 ± 0.14, p < 0.05) and overt hypothyroidism (1.13 ± 0.98, p < 0.05). Change of aortic stiffness correlated with change of free-thyroxine (fT4), vWF and fibrinogen levels in a positive manner.

CONCLUSION

Long-term thyrotropin-suppression therapy has continuous adverse effects on the arterial wall. The degree of TSH suppression in patients with DTC should be kept at the possible minimum, based on individually determined potential benefits and risks of treatment, especially in patients with cardiovascular co-morbidities.

Effects of Add-on Therapy Consisting of a Selective Mineralocorticoid Receptor Blocker on Arterial Stiffness in Patients with Uncontrolled Hypertension

OBJECTIVE

Aldosterone plays an important role in the pathogenesis of atherosclerosis; however, the significance of mineralocorticoid receptor blockade for atherosclerosis has not been fully elucidated. In this study, the effect of add-on eplerenone on the degree of arterial stiffness was examined in patients with uncontrolled hypertension.

METHODS

Forty-seven uncontrolled hypertensive patients who had previously been treated with anti-hypertensive drugs were examined retrospectively. Thirty-two patients received add-on therapy consisting of eplerenone (Group E) and 15 patients received add-on therapy with a Calcium channel blocker (CCB) or an increased dose of CCB (Group C) in addition to their baseline medications. Both the systolic blood pressure (SBP) and diastolic blood pressure (DBP) values were significantly decreased at two and 12 months in Group C. In contrast, neither the SBP nor DBP values were significantly changed at two months and eventually decreased at 12 months in Group E. The degree of arterial stiffness, as evaluated according to the cardio-ankle vascular index (CAVI), did not improve at either two or 12 months in Group C, whereas the CAVI values improved as early as at two months and the improvement was sustained at 12 months in Group E. The extent of change in the CAVI was not associated with the level of changes in the SBP or DBP values in Group E.

CONCLUSION

Treatment with eplerenone added to the patient's baseline medications improves the degree of arterial stiffness as early as at two months after the beginning of treatment, independent of the blood pressure-lowering actions of these drugs in patients with uncontrolled hypertension.

Effects of estrogen intervention on the biomechanical characteristics of serum SOD, MDA, and middle cerebral artery in aged female rats

OBJECTIVE

This study aims to study the biological and biomechanical characteristics of the middle cerebral artery (MCA) in aged and estrogen-intervened aged rats, thereby providing biomechanical basis for clinics.

MATERIALS AND METHODS

Thirty 18-month-old Sprague Dawley (SD) rats, 30 18-month-old estrogen-intervened SD rats, and 30 four-month-old SD rats were studied. The estrogen-intervened rats were given estradiol benzoate on the fifth feeding day. Thirty-four days after the feeding, the serum of each rat was obtained. The radioimmunoassay was performed for the content determination of serum E2, ER, malondialdehyde (MDA), and superoxide dismutase (SOD). The tensile test was performed to evaluate the MCA of each rat.

RESULTS

Through the estrogen intervention, the serum contents of E2, ER, SOD, and MDA in old rats were restored to normal levels. The maximum stress, maximum strain, and elastic limit of the MCA in the aged estrogen-intervened rat group were greater than those of the non-intervened aged rat group, with a significant difference (p < 0.05). The elastic modulus in the aged estrogen-intervened rat group was less than that of the non-intervened aged rat group, with a significant difference (p < 0.05).

CONCLUSION

E2 intervention can improve the flexibility, toughness, and compliance of MCA in aged rats.

[The influence of antihypertensive treatment on arterial stiffness, shear stress and activity of chosen matrix metalloproteinases]

The aim of the study was to compare therapeutic effects of chosen antihypertensive drugs on arterial stiffness, shear stress in carotid arteries and metalloproteinases activity, moreover analysis of relationship of these variables in the course of treatment.

METHODS

95 patients with essential arterial hypertension stage 1 or 2 were randomized to 6 months monotherapy with: quinapril, amlodipine, hydrochlorothiazide, losartan or bisoprolol. Each therapeutic group consisted of 19 patients (N=19). Before and then after 1, 3 and 6 months of treatment carotid-femoral pulse wave velocity (PWV) by using a Complior device, ultrasound of carotid arteries were performed. Blood samples for the measurement of whole blood viscosity were taken during each visit. Shear stress (SS) was calculated using measured variables: blood viscosity and velocity of blood flow. Serum concentration of metalloproteinase 3 (MMP-3) and plasma concentration of tissue inhibitor of metalloproteinase I (TIMP-1) were measured at the initial visit and after 6 months of treatment.

RESULTS

ANOVA for repeated measurements revealed for all groups significant decrease of PWV (ΔPWV) and MMP-3 (ΔMMP-3) concentration and increase of shear stress in carotid artery and TIMP-1 (ΔTIMP-1) concentration (p<0.05). No between groups differences appeared in above effects (p>0.05). The multiple regression analysis for the change of PWV (ΔPWV) in the study group considering all investigated variables at R2 = 0,27 revealed its significant relation to PWV at first visit, ΔTIMP-1, ΔMMP-3 and Δ shear stress counted for the maximum flow velocity in common carotid artery. Conclusion: Irrespectively of chosen drug we observed similar effect for PWV drop. Reduction of arterial stiffness as a result of antihypertensive therapy is strongly connected with shear stress increase that is secondary to blood flow velocity growth and changes in connective tissue metabolism.

Effect of aliskiren on circulating endothelial progenitor cells and vascular function in patients with type 2 diabetes and essential hypertension

BACKGROUND

The aim of this study was to investigate the effects of aliskiren on vascular function and endothelial progenitor cells (EPCs) in patients with type 2 diabetes and essential hypertension.

METHODS

The study enrolled type 2 diabetic patients aged >50 years under stable glycemic control and first diagnosed mild essential hypertension. In phase A (n = 20), patients received aliskiren 150-300 mg daily for 3 months. In phase B (n = 12), hydrochlorothiazide (HCTZ) 12.5-25mg daily substituted for aliskiren for 3 more months. At baseline and at the end of each phase, we assessed (i) brachial blood pressure (BBP); (ii) central aortic systolic pressure (CSP), aortic augmentation index (Aix), and pulse wave velocity (PWV) as markers of arterial stiffness; (iii) brachial artery flow-mediated dilatation (FMD) as a marker of endothelial function; (iv) left ventricular (LV) twisting and untwisting as markers of LV function and (v) EPC numbers in culture of peripheral blood mononuclear cells.

RESULTS

Aliskiren similarly reduced BBP and CSP, increased FMD (P < 0.001) and EPC numbers (P < 0.001), decreased PWV and Aix (P < 0.05), and improved LV twisting and untwisting (P < 0.05). Although substitution of HCTZ sustained BBP at similar levels, CSP and echocardiographic indices nearly returned at baseline levels, and the improvement of FMD, PWV, Aix, and EPC numbers was abolished.

CONCLUSIONS

Aliskiren had a favorable effect on endothelial function and EPCs, reduced arterial stiffness, and improved LV twisting and untwisting. These effects were independent of BBP lowering, as they were not observed after the achievement of similar values of BBP with HCTZ.

Calcium Channel Blockers--Benefits Upon Vascular Biology in Hypertensive Patients

Calcium channel blockers (CCB) are widely used in cardiovascular medicine expressing high hopes upon decreasing cardiovascular risk, morbidity and mortality. Here, the potency of CCBs on 58 Romanian asymptomatic hypertensive patients, with no atherothrombotic cardiovascular disease, was studied by clinical and in silico methods. In our study, arterial elasticity/stiffness was assessed; anthropometric, metabolic (lipidic) parameters were quantified. We concluded that lercanidipine 10 mg once daily, during three weeks, is able to dramatically improve central aortic systolic blood pressure, aortic pulse wave velocity. Lipid profile improvement is an essential condition to improve elastic vascular properties in order to decrease the risk for further cardiovascular events. Besides, the potency of lercanidipine is expressed as the contribution of molecular descriptors (van der Waals and solvent accessible surface areas), electronic (molecular polarisability) and hydrophobic (water/octanol partition coefficient) by means of blocker effect on calcium channel, compared with cilnidipine and other 30 dihydropyridines, using molecular simulation techniques.

Effect of vildagliptin on hsCRP and arterial stiffness in patients with type 2 diabetes mellitus

OBJECTIVE

To evaluate the effect of dipeptidyl-peptidase-4 (DPP-4) inhibitor vildagliptin on high sensitivity C-reactive protein (hsCRP) and arterial stiffness (AS) in patients with type 2 diabetes (T2DM).

DESIGN

Sixty-four drug-naive diabetic patients, with inadequate glycemic control, participated in this randomized, open-label study. Half of the patients received metformin 1700 mg/d and the other half of them received metformin 1700 mg/d plus vildagliptin 100 mg/d. AS was measured by carotid-femoral Pulse Wave Velocity (cfPWV). Body weight (BW), body mass index (BMI), blood pressure (BP), hsCRP, glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), lipid profile, albumin/creatinine ratio (ACR), fasting insulin, C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function (HOMA-β) were also assessed at baseline and after 6 months.

RESULTS

Vildagliptin in combination with metformin had a beneficial influence on hsCRP, HbA1c, C-peptide and HOMA-β index (p <0.05) but had no effect on cfPWV, BP, BW, BMI, lipid profile, ACR and HOMA-IR compared with metformin alone (p=NS).

CONCLUSIONS

We have found that the addition of vildagliptin to metformin for a period of six months decreased hsCRP, improved glycemic control and β-cell function but had no effect on AS in drug-naive patients with T2DM.

The Effects of Atorvastatin on Arterial Stiffness in Male Patients with Type 2 Diabetes

Statin therapy improves lipid profiles and reduces vascular inflammation, but its effects on central arterial stiffness in type 2 diabetes are unclear. The aim of this study was to determine whether statin therapy reduces central arterial stiffness, in a dose-dependent manner, in male patients with type 2 diabetes. Fifty-one patients ceased statin therapy for 6 weeks, followed by randomisation to either 10 or 80 mg of atorvastatin. At randomization, 3 and 12 months, central arterial stiffness was measured via carotid-femoral pulse wave velocity (PWV), along with serum markers of vascular inflammation including high-sensitivity c-reactive protein (hsCRP) and osteoprotegerin (OPG). PWV decreased from 10.37 ± 1.30 to 9.68 ± 1.19 m/sec (p < 0.01 from baseline) at 3 months and 9.10 ± 1.17 m/sec (p < 0.001 from baseline) at 12 months. hsCRP and OPG decreased significantly at 3 and 12 months. Reductions in PWV did not differ significantly between the groups. Baseline PWV and OPG values correlated strongly (r = 0.48, p < 0.01), as did their response to atorvastatin over 12 months (r = 0.36 delta-OPG and delta-PWV, p < 0.01). Atorvastatin therapy appeared to reduce central arterial stiffness in male type 2 diabetes, with no dose-dependent effect observed. The correlation observed between reductions in PWV and OPG suggests that atorvastatin reduces PWV via direct anti-inflammatory effects on the vasculature.

Differential effects of nebivolol and metoprolol on arterial stiffness, circulating progenitor cells, and oxidative stress

Unlike traditional beta receptor antagonists, nebivolol activates nitric oxide. We hypothesized that therapy with nebivolol compared with metoprolol would improve arterial stiffness, increase levels of circulating progenitor cells (PC), and decrease oxidative stress (OS). In a randomized, double-blind, cross-over study, 30 hypertensive subjects received either once daily nebivolol or metoprolol succinate for 3 months each. Pulse wave velocity and augmentation index were measured using tonometry. Flow cytometry was used to measure circulating PC. OS was measured as plasma aminothiols. Measurements were performed at baseline, and repeated at 3 and 6 months. No significant differences were present between the levels of OS, arterial stiffness, and PC numbers during treatment with metoprolol compared with nebivolol. In subgroup analyses of beta-blocker naïve subjects (n = 19), nebivolol reduced pulse wave velocity significantly compared with metoprolol (-1.4 ± 1.9 vs. -0.1 ± 2.2; P = .005). Both nebivolol and metoprolol increased circulating levels of CD34+/CD133 + PC similarly (P = .05), suggesting improved regenerative capacity.

Treatment with continuous subcutaneous insulin infusion is associated with lower arterial stiffness

AIMS

To investigate the relationship between arterial stiffness and insulin treatment mode [continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI)] in type 1 diabetes patients.

METHODS

Cross-sectional study, from 2009 to 2011, including 601 Caucasian type 1 diabetes patients, 58 and 543 treated with CSII and MDI, respectively. Arterial stiffness was measured as pulse wave velocity (PWV) (SphygmoCor, AtCor Medical). Adjustment included gender, age, diabetes duration, HbA1c, heart rate, mean arterial pressure, P-creatinine, urinary albumin excretion rate (UAER), smoking, total daily insulin dose, antihypertensive treatment, previous cardiovascular disease (CVD), total cholesterol and statin treatment. Albuminuria was UAER ≥30 mg/24-h, and CVD included myocardial infarction, revascularization, peripheral arterial disease and stroke.

RESULTS

CSII- versus MDI-treated patients were 48 versus 57 % men, 51 ± 11 versus 54 ± 13 years old (mean ± SD), had 33 ± 12 versus 32 ± 16 years diabetes duration and HbA1c 7.8 ± 0.9 % (62 ± 10 mmol/mol) versus 8.0 ± 1.2 % (64 ± 13 mmol/mol) (P ≥ 0.08 for all). PWV was lower in CSII- versus MDI-treated patients (9.3 ± 2.8 vs. 10.4 ± 3.4 m/s; P = 0.016). In fully adjusted analysis, CSII treatment was significantly (P = 0.038) associated with lower PWV, whereas HbA1c-level was not (P = 0.93).

CONCLUSIONS

In type 1 diabetes patients, CSII treatment was associated with lower arterial stiffness independent of other risk factors, while HbA1c was not. Although glucose variability was not assessed, our results suggest that glucose variability and not HbA1c-level affect arterial stiffness. This needs confirmation in randomised prospective studies.

A feasibility study of the association of exposure to biomass smoke with vascular function, inflammation, and cellular aging

BACKGROUND

Biomass smoke at higher concentrations is associated with respiratory symptoms and, after years of exposure, increased risk of respiratory disorders in adults, but its effects on cardiovascular diseases are not well characterized, particularly compared with other pollution sources like tobacco smoke or traffic.

METHODS

We conducted a cross-sectional study and enrolled 25 women living in rural Sichuan, China. We measured integrated 24-h personal exposure to fine particulate matter (PM2.5) and black carbon, and measured PM2.5 and black carbon in their kitchens. We assessed participants' brachial and central blood pressure and arterial stiffness using pulse wave analysis, and analyzed dried blood spot and buccal cell samples for C-reactive protein and relative telomere length. We also evaluated the difference in these physiological and biomarker measures between individuals with high (≥median) versus low (<median) PM2.5 exposure using multivariate regression.

RESULTS

Geometric mean 24-h PM2.5 and black carbon exposures were 61 µg/m(3) (95% CI: 48, 78) and 3.2 µg/m(3) (95% CI: 2.3, 4.5), respectively. Average kitchen PM2.5 and black carbon concentrations were only moderately correlated with personal exposures (PM2.5: r=0.41; black carbon: r=0.63), although they had similar means. Women in the high and low exposure groups were similar in age, obesity, socioeconomic status, salt intake, and physical activity. Women in the high PM2.5 exposure group had higher mean brachial systolic blood pressure (SBP; difference=4.6 mmHg, 95% CI -7.8, 16.9), central SBP (difference=3.1 mmHg, 95% CI: -8.4, 14.5), central pulse pressure (difference=4.1 mmHg; 95% CI: -4.2, 12.4), and augmentation index (difference=2.8%, 95% CI: -1.6, 7.2). High exposed women had 43% shorter telomere length (95% CI: -113, 28) than that of women in the low exposure group. There were no differences in pulse wave velocity or C-reactive protein between the two exposure groups. None of the results was statistically significant.

CONCLUSIONS

Our results suggest that it is feasible to measure markers of vascular function and biomarkers of inflammation and oxidative stress in field studies of biomass smoke. Although many of the associations were in the expected direction, larger studies would be needed to establish the effects.

Active vitamin D and accelerated progression of aortic stiffness in hemodialysis patients: a longitudinal observational study

BACKGROUND

We hypothesized that high-dose active vitamin D therapy in the form of alphacalcidol (α-calcidol), used to treat secondary hyperparathyroidism in chronic kidney disease, could lead to vascular calcification and accelerated progression of aortic stiffness.

METHODS

We conducted an observational study in 85 patients on chronic hemodialysis, among which 70 were taking a weekly dose of α-calcidol of <2 µg and 15 were taking a weekly dose of ≥2 µg (pharmacological dose). Parathyroid hormone, 25-hydroxyvitamin D, fibroblast growth factor 23, and α-klotho were determined. Aortic stiffness was assessed by determination of carotid-femoral pulse wave velocity (cf-PWV) at baseline and after a mean follow-up of 1.2 years. A multivariable regression model was used to evaluate the impact of pharmacological dose of α-calcidol on the progression of aortic stiffness.

RESULTS

At baseline, clinical, biological, and hemodynamic parameters were similar. At follow-up, cf-PWV increased more in patients with pharmacological dose of α-calcidol (0.583±2.291 m/s vs. 1.948±1.475 m/s; P = 0.04). After adjustment for changes in mean blood pressure and duration of follow-up, pharmacological dose of α-calcidol was associated with a higher rate of progression of cf-PWV (0.969 m/s; 95% confidence interval = 0.111-1.827; P = 0.03), and this association persisted after further adjustments for parameters of mineral metabolism.

CONCLUSIONS

In this study, pharmacological dose of α-calcidol was associated with accelerated progression of aortic stiffness. This study suggest that the vascular safety of active vitamin D posology may need to be specifically addressed in the treatment of chronic kidney disease-related bone mineral disorder.

Diurnal variation in blood pressure and arterial stiffness in chronic kidney disease: the role of endothelin-1

Hypertension and arterial stiffness are important independent cardiovascular risk factors in chronic kidney disease (CKD) to which endothelin-1 (ET-1) contributes. Loss of nocturnal blood pressure (BP) dipping is associated with CKD progression, but there are no data on 24-hour arterial stiffness variation. We examined the 24-hour variation of BP, arterial stiffness, and the ET system in healthy volunteers and patients with CKD and the effects on these of ET receptor type A receptor antagonism (sitaxentan). There were nocturnal dips in systolic BP and diastolic BP and pulse wave velocity, our measure of arterial stiffness, in 15 controls (systolic BP, −3.2±4.8%, P<0.05; diastolic BP, −6.4±6.2%, P=0.001; pulse wave velocity, −5.8±5.2%, P<0.01) but not in 15 patients with CKD. In CKD, plasma ET-1 increased by 1.2±1.4 pg/mL from midday to midnight compared with healthy volunteers (P<0.05). Urinary ET-1 did not change. In a randomized, double-blind, 3-way crossover study in 27 patients with CKD, 6-week treatment with placebo and nifedipine did not affect nocturnal dips in systolic BP or diastolic BP between baseline and week 6, whereas dipping was increased after 6-week sitaxentan treatment (baseline versus week 6, systolic BP: −7.0±6.2 versus −11.0±7.8 mm Hg, P<0.05; diastolic BP: −6.0±3.6 versus −8.3±5.1 mm Hg, P<0.05). There was no nocturnal dip in pulse pressure at baseline in the 3 phases of the study, whereas sitaxentan was linked to the development of a nocturnal dip in pulse pressure. In CKD, activation of the ET system seems to contribute not only to raised BP but also the loss of BP dipping. The clinical significance of these findings should be explored in future clinical trials.

Aortic and carotid arterial stiffness and epigenetic regulator gene expression changes precede blood pressure rise in stroke-prone Dahl salt-sensitive hypertensive rats

Multiple clinical studies show that arterial stiffness, measured as pulse wave velocity (PWV), precedes hypertension and is an independent predictor of hypertension end organ diseases including stroke, cardiovascular disease and chronic kidney disease. Risk factor studies for arterial stiffness implicate age, hypertension and sodium. However, causal mechanisms linking risk factor to arterial stiffness remain to be elucidated. Here, we studied the causal relationship of arterial stiffness and hypertension in the Na-induced, stroke-prone Dahl salt-sensitive (S) hypertensive rat model, and analyzed putative molecular mechanisms. Stroke-prone and non-stroke-prone male and female rats were studied at 3- and 6-weeks of age for arterial stiffness (PWV, strain), blood pressure, vessel wall histology, and gene expression changes. Studies showed that increased left carotid and aortic arterial stiffness preceded hypertension, pulse pressure widening, and structural wall changes at the 6-week time-point. Instead, differential gene induction was detected implicating molecular-functional changes in extracellular matrix (ECM) structural constituents, modifiers, cell adhesion, and matricellular proteins, as well as in endothelial function, apoptosis balance, and epigenetic regulators. Immunostaining testing histone modifiers Ep300, HDAC3, and PRMT5 levels confirmed carotid artery-upregulation in all three layers: endothelial, smooth muscle and adventitial cells. Our study recapitulates observations in humans that given salt-sensitivity, increased Na-intake induced arterial stiffness before hypertension, increased pulse pressure, and structural vessel wall changes. Differential gene expression changes associated with arterial stiffness suggest a molecular mechanism linking sodium to full-vessel wall response affecting gene-networks involved in vascular ECM structure-function, apoptosis balance, and epigenetic regulation.

Increased aortic stiffness elevates pulse and mean pressure and compromises endothelial function in Wistar rats

An increase in pulse pressure (PP) is highly associated with hypertension. The goal of this study was to determine the effect of increased aortic stiffness on PP and endothelial dysfunction as precursors to hypertension. A rat model of suddenly increased aortic stiffness by use of a nonconstrictive restraint (glue coating) on aortic surface was created to investigate the change of PP and mean arterial pressure (MAP). Group I (n = 16) underwent aorta restraint for 4 wk. Group II (n = 12) underwent aortic restraint for 4 wk, followed by restraint removal to evaluate extent of reversibility for additional 4 wk. The aortic and peripheral endothelial function was assessed by ACh-stimulated endothelium-dependent vasodilation. The level of nitrate/nitrite (NOx), endothelin-1 (ET-1), and prostacyclin (PGI2) were measured in the serum and artery tissue. We found that aortic stiffening causes a significant increase in PP and MAP (P < 0.05). The endothelial function was markedly blunted (P < 0.05) in both aorta and small peripheral artery. After removal of the restraint, the impaired endothelium function persisted in the aorta likely due to sustained deterioration of aortic wall, but was partially restored in peripheral artery. The endothelial dysfunction was correlated with a decrease in NOx and PGI2 (P < 0.05) and an increase in ET-1 (P < 0.05). Our results show that aortic stiffening results in widening of PP, which affected endothelium function through changes in synthesis of NOx, ET-1, and PGI2. These findings suggest that increased aortic stiffness may be a cause of increased PP and a precursor to hypertension.

Can suppression of inflammation by anti-TNF prevent progression of subclinical atherosclerosis in inflammatory arthritis?

OBJECTIVE

It remains a matter of debate whether TNF-a antagonists have favourable effects on the cardiovascular (CV) system. This systematic review evaluates the effect of TNF-a blockers on the progression of subclinical atherosclerosis and arterial stiffness in patients with inflammatory arthritis.

METHODS

A search of the MEDLINE and Web of Knowledge databases was conducted to identify studies into the effect of TNF-a antagonists on subclinical atherosclerosis and arterial stiffness in patients with RA, AS and PsA. Carotid intimamedia thickness (cIMT) was used to assess subclinical atherosclerosis. Two methods were used to assess arterial stiffness: pulse wave velocity (PWV) and aortic augmentation index (AIx). Twenty-three studies matching the search criteria were included for analysis.

RESULTS

TNF-a blockers probably are effective in preventing (7/13 studies) or even reversing (5/13 studies) the progression of IMT in patients with RA, AS and PsA who are responding to treatment. With regard to arterial stiffness, PWV was either significantly reduced (7/13 studies) or remained unchanged (6/13 studies) following TNF-a antagonist treatment. Nonetheless, most studies in RA (7/10) reported significant improvement of PWV. AIx remained unchanged in 10 of 13 studies.

CONCLUSION

The balance of evidence suggests that TNF-a antagonists may have a beneficial effect on preventing the progression of subclinical atherosclerosis and arterial stiffness. It remains unknown whether this effect is specific to TNF-a antagonists or relates to better control of inflammation irrespective of the disease modification strategy by which this is achieved.

[Pulse wave velocity and pulse pressure in patients with arterial hypertension]

The article is devoted to assessment of pulse pressure (PP) in female postmenopausal patients and patients with arterial hypertension (AH) older than 55 years. It is shown that in postmenopausal women even aged 55 years or less PP is one of most important parameters associated with target organ damage. Conclusion about presence of elevated vascular wall stiffness in these women as in elderly patients can be made at PP more or equal 60 mm Hg. In elderly patients both with isolated systolic AP and 1-2 degree systolic-diastolic monotherapy with indapamide 1,5 mg retard allows not only to achieve clear-cut hypotensive effect but in both variants of AH to lower PP. This can substantially decrease degree of cardiovascular risk without crossing bottom borders of diastolic AP lowering. The latter is especially important for elderly patients with isolated systolic AH.

The effect of high-dose vitamin D supplementation on insulin resistance and arterial stiffness in patients with type 2 diabetes

BACKGROUND/AIMS

Recent epidemiological studies revealed a striking inverse relationship between vitamin D levels, glucose intolerance/insulin resistance (IR), and cardiovascular disease. However, few interventional studies have evaluated the effect of vitamin D supplementation on cardiovascular risk, such as IR and arterial stiffness, in diabetes. We investigated the role of vitamin D supplementation on cardiovascular risk in type 2 diabetes patients, including metabolic parameters, IR, and arterial stiffness.

METHODS

We enrolled patients who were taking antidiabetic medications or managed their diabetes using lifestyle changes. We excluded patients who were taking vitamin D or calcium supplements. We randomized participants into the vitamin D group (cholecalciferol 2,000 IU/day + calcium 200 mg/day, n = 40) or the placebo group (calcium 200 mg/day, n = 41). We compared their IR (homeostasis model of assessment [HOMA]-IR) and arterial stiffness (brachial-ankle pulse wave velocity and radial augmentation index) before and after 24 weeks of intervention.

RESULTS

The baseline characteristics of the two groups were similar. A total of 62 participants (placebo, 30; vitamin D, 32) completed the study protocol. At the end of the study period, the 25-hydroxyvitamin D [25(OH)D] levels were significantly higher in the vitamin D group than in the placebo group (35.4 ± 8.5 ng/mL vs. 18.4 ± 7.3 ng/mL, p < 0.001). There was no difference in HOMA-IR or changes in arterial stiffness (placebo, 21, vitamin D, 24) between the groups.

CONCLUSIONS

Our data suggest that high-dose vitamin D supplementation might be effective in terms of elevating 25(OH)D levels. However, we identified no beneficial effects on cardiovascular risk in type 2 diabetes, including IR and arterial stiffness.

Effect of Rg3-enriched Korean red ginseng (Panax ginseng) on arterial stiffness and blood pressure in healthy individuals: a randomized controlled trial

Ginsenoside Rg3, present in steamed ginseng (Panax Ginseng C.A. Meyer), is thought to be a potent modulator of vascular function. Our objective was to clinically evaluate acute effects of ginsenoside Rg3-enriched Korean red ginseng (Rg3-KRG) on measures of arterial stiffness and peripheral and central blood pressure (BP) parameters in healthy volunteers. Using a double-blind, randomized, crossover design, 23 individuals (9 males:14 females; age, 25 ± 2 years; body mass index, 22 ± 0.6 kg/m(2); systolic BP/diastolic BP, 113 ± 3/70 ± 2 mm Hg) were administered 400-mg Rg3-KRG extract or 400-mg wheat bran control on two separate visits with a 7-day washout period. Aortic augmentation index and central BP were measured using applanation tonometry by radial pulse wave analysis, and peripheral BP was evaluated oscillometrically. Measurements were taken at baseline and at 1, 2, and 3 hours after intervention. Compared with control, there were significant reductions in augmentation index (-4.3 ± 8.9%, P = .03), central (-4.8 ± 6.8 mm Hg, P = .01) and brachial mean arterial pressure (-4.4 ± 6.6 mm Hg, P = .01), central systolic (-5.0 ± 7.9 mm Hg, P = .01) and diastolic BP (-3.9 ± 6.6 mm Hg, P = .01), and brachial systolic (-4.4 ± 10.0 mm Hg, P = .048) and diastolic BP (-3.6 ± 6.4 mm Hg, P = .01) at 3 hours after intervention compared with control. This study is the first to demonstrate Rg3-KRG extract acutely lowers central and peripheral arterial pressures in healthy adults. Further clinical evaluation is desired to quantify efficacy in higher risk individuals and in long-term settings.

Association between brachial-ankle pulse wave velocity and the ratio of l-arginine to asymmetric dimethylarginine in patients undergoing coronary angiography

BACKGROUND

Endothelial dysfunction causes vasomotor dysregulation and vascular stiffening in addition to structural changes. By influencing NO synthesis, deficiency of l-arginine relative to asymmetric dimethylarginine (ADMA), which is an l-arginine derivative that acts as a competitive NO synthase inhibitor, may lead to the promotion of arterial stiffness. This study investigated the relationship between the l-arginine/ADMA ratio and brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness.

METHODS AND RESULTS

This cross-sectional study enrolled 74 patients (62 men, 12 women; mean age, 67±10 years) undergoing elective coronary angiography. A total of 54 (73%) patients had coronary artery disease. Serum l-arginine and ADMA were measured by high-performance liquid chromatography with fluorescence detection. The ratio of l-arginine to ADMA and the serum l-arginine level was associated with baPWV in univariate regression analysis (l-arginine/ADMA ratio: β=-0.323, p=0.005; l-arginine: β=-0.247, p=0.034). In addition, baPWV was related to blood hemoglobin concentration, hematocrit, brain natriuretic peptide level, symmetric dimethylarginine, renal function, blood pressure, and heart rate. In multivariate analysis, the l-arginine/ADMA ratio was a significant predictor of baPWV (β=-0.310, p<0.001). In subgroup analyses, the l-arginine/ADMA ratio was associated with baPWV in elderly patients (n=46, β=-0.359, p=0.004), and in younger patients (n=28, β=-0.412, p=0.006).

CONCLUSION

A low l-arginine/ADMA ratio may be associated with high baPWV in patients undergoing coronary angiography.

Stiffening-induced high pulsatility flow activates endothelial inflammation via a TLR2/NF-κB pathway

Stiffening of large arteries is increasingly used as an independent predictor of risk and therapeutic outcome for small artery dysfunction in many diseases including pulmonary hypertension. The molecular mechanisms mediating downstream vascular cell responses to large artery stiffening remain unclear. We hypothesize that high pulsatility flow, induced by large artery stiffening, causes inflammatory responses in downstream pulmonary artery endothelial cells (PAECs) through toll-like receptor (TLR) pathways. To recapitulate the stiffening effect of large pulmonary arteries that occurs in pulmonary hypertension, ultrathin silicone tubes of variable mechanical stiffness were formulated and were placed in a flow circulatory system. These tubes modulated the simulated cardiac output into pulsatile flows with different pulsatility indices, 0.5 (normal) or 1.5 (high). PAECs placed downstream of the tubes were evaluated for their expression of proinflammatory molecules (ICAM-1, VCAM-1, E-selectin and MCP-1), TLR receptors and intracellular NF-κB following flow exposure. Results showed that compared to flow with normal pulsatility, high pulsatility flow induced proinflammatory responses in PAECs, enhanced TLR2 expression but not TLR4, and caused NF-κB activation. Pharmacologic (OxPAPC) and siRNA inhibition of TLR2 attenuated high pulsatility flow-induced pro-inflammatory responses and NF-κB activation in PAECs. We also observed that PAECs isolated from small pulmonary arteries of hypertensive animals exhibiting proximal vascular stiffening demonstrated a durable ex-vivo proinflammatory phenotype (increased TLR2, TLR4 and MCP-1 expression). Intralobar PAECs isolated from vessels of IPAH patients also showed increased TLR2. In conclusion, this study demonstrates for the first time that TLR2/NF-κB signaling mediates endothelial inflammation under high pulsatility flow caused by upstream stiffening, but the role of TLR4 in flow pulsatility-mediated endothelial mechanotransduction remains unclear.

Harmful and beneficial relationships between alcohol consumption and subclinical atherosclerosis

BACKGROUND AND AIMS

Arterial stiffness and increased intima-media wall thickness are two of the main predictors of cardiovascular disease (CVD). We evaluated whether brachial-ankle pulse wave velocity (baPWV) and common carotid artery intima-media wall thickness (CCA-IMT) are correlated with alcohol consumption in a cross-sectional study among Korean men and women aged 40 years and over.

METHODS AND RESULTS

All 5539 subjects (2121 men and 3418 women) were participants in the Multi-Rural Communities cohort (MRcohort) study, a part of the Korean Genome Epidemiology Study (KoGES). The baPWV was positively correlated with alcohol consumption in men (p for trend <0.0001). Age (middle-aged versus elderly) modified the effect of alcohol consumption on PWV. On the other hand CCA-IMT decreased with alcohol consumption in men. There was no favorable zone of alcohol consumption in terms of baPWV and CCA-IMT. Adjustment for lipid profiles substantially attenuated the relationship between alcohol consumption and CCA-IMT. There was no clear relation between alcohol consumption and baPWV/CCA-IMT in women.

CONCLUSIONS

Along with a linear harmful relationship between alcohol consumption and arterial stiffness in men there may also be a beneficial relationship between alcohol consumption and carotid intima-wall thickness. The effect of alcohol on arterial stiffness may be slightly stronger in elderly men, and the effect of alcohol on CCA-IMT may be mediated by lipid factors.

Flavonoids and arterial stiffness: promising perspectives

BACKGROUND AND AIMS

Flavonoids are a group of polyphenol compounds, ubiquitously found in plants. Great emphasis has been given to their possible benefits for cardiovascular health. These beneficial effects may be mediated by a specific action on arterial walls. Arterial stiffness is a marker of vascular aging, increasingly used in the clinical setting and assessed by pulse wave velocity. It has shown to be a robust predictor of cardiovascular events and mortality. This review aims at providing a comprehensive evaluation of available intervention and observational studies examining the relationship between flavonoid consumption and arterial stiffness.

DATA SYNTHESIS

A Medline(®) literature search was performed using the keywords "arterial stiffness" and "flavonoids". As a result, 2 cross-sectional and 16 intervention studies assessing the relationship between flavonoids intake and arterial stiffness were retained. Four intervention trials reported a significant decrease of arterial stiffness after a flavonoid-based intervention, independently from blood pressure changes. The two observational studies reported significant associations between a higher flavonoid consumption and a lower arterial stiffness. In this review, isoflavones, anthocyanins and to a lesser extent cocoa flavan-3-ols appeared to be the more efficient to improve vascular function.

CONCLUSIONS

Despite their heterogeneity, preliminary data seem to support an improvement of the arterial stiffness related to flavonoid intake. However, further research on absorption and dose-response effects of the specific flavonoid subclasses on arterial structure is warranted.

Effects of watermelon supplementation on aortic hemodynamic responses to the cold pressor test in obese hypertensive adults

BACKGROUND

Cold-induced increases in aortic blood pressure (BP) may cause adverse cardiac events in hypertensives by increasing ventricular afterload. L-citrulline supplementation reduces BP at baseline and during the cold pressor test (CPT), but the effect on wave reflection (augmentation pressure (AP) and index (AIx)) is controversial. Our aim was to assess the effect of L-citrulline-rich watermelon supplementation on aortic hemodynamic responses to CPT in hypertensive adults.

METHODS

Brachial systolic BP (bSBP) and aortic systolic BP (aSBP), AP, AIx, AIx adjusted to 75 beats/min (AIx75), reflection time (Tr), first (P1) and second systolic peak (P2; wave reflection magnitude), heart rate (HR), and systolic time index (STI; myocardial oxygen demand) at baseline and during CPT and magnitude of the response from baseline to CPT were evaluated in 13 individuals (10 women; 57±1 year; bSBP 151±5 mm Hg). Participants were randomized to a 6-week watermelon or placebo supplementation in a crossover design.

RESULTS

Watermelon reduced (P < 0.05) bSBP, aSBP, P1, and P2 at baseline and CPT compared with placebo; thus, increases from baseline to CPT were unaffected. Watermelon did not affect AP, AIx, AIx75, and STI at baseline but decreased (P < 0.05) AP and STI during CPT and the increases in AP (~5mm Hg) and AIx75 (~7.3%) from baseline to CPT.

CONCLUSIONS

Watermelon supplementation reduced aortic BP and myocardial oxygen demand during CPT and the magnitude of the cold-induced increase in wave reflection in obese adults with hypertension. Watermelon may provide cardioprotection by attenuating cold-induced aortic hemodynamic responses.

CLINICAL TRIALS REGISTRATION

Clinicaltrial.gov register, NCT01185041.

Effects of oral lycopene supplementation on vascular function in patients with cardiovascular disease and healthy volunteers: a randomised controlled trial

AIMS

The mechanisms by which a 'Mediterranean diet' reduces cardiovascular disease (CVD) burden remain poorly understood. Lycopene is a potent antioxidant found in such diets with evidence suggesting beneficial effects. We wished to investigate the effects of lycopene on the vasculature in CVD patients and separately, in healthy volunteers (HV).

METHODS AND RESULTS

We randomised 36 statin treated CVD patients and 36 healthy volunteers in a 2∶1 treatment allocation ratio to either 7 mg lycopene or placebo daily for 2 months in a double-blind trial. Forearm responses to intra-arterial infusions of acetylcholine (endothelium-dependent vasodilatation; EDV), sodium nitroprusside (endothelium-independent vasodilatation; EIDV), and NG-monomethyl-L-arginine (basal nitric oxide (NO) synthase activity) were measured using venous plethysmography. A range of vascular and biochemical secondary endpoints were also explored. EDV in CVD patients post-lycopene improved by 53% (95% CI: +9% to +93%, P = 0.03 vs. placebo) without changes to EIDV, or basal NO responses. HVs did not show changes in EDV after lycopene treatment. Blood pressure, arterial stiffness, lipids and hsCRP levels were unchanged for lycopene vs. placebo treatment groups in the CVD arm as well as the HV arm. At baseline, CVD patients had impaired EDV compared with HV (30% lower; 95% CI: -45% to -10%, P = 0.008), despite lower LDL cholesterol (1.2 mmol/L lower, 95% CI: -1.6 to -0.9 mmol/L, P<0.001). Post-therapy EDV responses for lycopene-treated CVD patients were similar to HVs at baseline (2% lower, 95% CI: -30% to +30%, P = 0.85), also suggesting lycopene improved endothelial function.

CONCLUSIONS

Lycopene supplementation improves endothelial function in CVD patients on optimal secondary prevention, but not in HVs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01100385.

Impact of lifetime opioid exposure on arterial stiffness and vascular age: cross-sectional and longitudinal studies in men and women

OBJECTIVE

To characterise and compare the potentiation of arterial stiffness and vascular ageing by opioids in men and women.

DESIGN

Cross-sectional and longitudinal studies of 576 clinical controls and 687 opioid-dependent patients (ODP) on 710 and 1305 occasions, respectively, over a total of 2382 days (6.52 years), 2006-2011. Methodology Radial pulse wave analysis with Atcor SphygmoCor system (Sydney).

SETTING

Primary care.

CONTROLS

General practice patients with non-cardiovascular disorders, and university student controls. ODP: Patients undergoing clinical management of their opioid dependence. CONTROLS had lower chronological ages (CAs) than ODP (30.0±0.5 vs 34.5±0.3, mean±SEM, p<0.0001). 69.6% and 67.7% participants were men, and 16% and 92.3% were smokers (p<0.0001) for controls and ODP, respectively. 86.3%, 10.3% and 3.4% of ODP were treated with buprenorphine (6.98±0.21 mg), methadone (63.04±4.01 mg) or implant naltrexone, respectively. Body mass index (BMI) was depressed in ODP.

INTERVENTIONS

Nil.

PRIMARY OUTCOME MEASURES

Vascular Reference Age (RA) and the ratio of vascular age to chronological age (RA/CA).

SECONDARY OUTCOME MEASURES

Arterial stiffness including Augmentation Index.

RESULTS

After BMI adjustment, RA in ODP was higher as a function of CA and of time (both p<0.05). Modelled mean RA in control and ODP was 35.6 and 36.3 years (+1.97%) in men, and 34.5 and 39.2 years (+13.43%) in women, respectively. Changes in RA and major arterial stiffness indices were worse in women both as a factor (p = 0.0036) and in interaction with CA (p = 0.0040). Quadratic, cubic and quartic functions of opioid exposure duration outperformed linear models with RA/CA over CA and over time. The opioid dose-response relationship persisted longitudinally after multiple adjustments from p=0.0013 in men and p=0.0073 in women.

CONCLUSIONS

Data show that lifetime opioid exposure, an interactive cardiovascular risk factor, particularly in women, is related to linear, quadratic, cubic and quartic functions of treatment duration and is consistent with other literature of accelerated ageing in patients with OD.

Effect of a tart cherry juice supplement on arterial stiffness and inflammation in healthy adults: a randomised controlled trial

Tart cherries are a particularly rich source of anthocyanins. Evidence indicates that dietary intake of anthocyanins is inversely associated with arterial stiffness. We conducted an open-label randomised placebo controlled study to determine whether a tart cherry juice concentrate (Cherry Active) reduced arterial stiffness, inflammation and risk markers for cardiovascular disease in 47 healthy adults (30-50 years). Participants consumed 30 ml of cherry concentrate diluted to a volume of 250 ml with water or the same volume of an energy matched control drink daily for six weeks. Measurements were taken at baseline and at the end of the intervention. There was no effect of the intervention on arterial stiffness (P = 0.218), c-reactive protein (P = 0.220), systolic blood pressure (P = 0.163), diastolic blood pressure (P = 0.121), total cholesterol (P = 0.342) and high density lipoprotein cholesterol (P = 0.127). At the end of the intervention, plasma antioxidant capacity (measured as the ferric reducing ability of plasma (FRAP)) was significantly higher in the intervention group than the control group (P = 0.012). We conclude that a tart cherry juice concentrate rich in anthocyanins has no effect on arterial stiffness, c-reactive protein and risk markers for cardiovascular disease, but evokes a minor increase in antioxidant status in healthy adults.

No association of dietary fiber intake with inflammation or arterial stiffness in youth with type 1 diabetes

AIM

To examine the association of dietary fiber intake with inflammation and arterial stiffness among youth with type 1 diabetes (T1D) in the US.

METHODS

Data are from youth ≥ 10 years old with clinically diagnosed T1D for ≥ 3 months and ≥ 1 positive diabetes autoantibody in the SEARCH for Diabetes in Youth Study. Fiber intake was assessed by food frequency questionnaire with measurement error (ME) accounted for by structural sub-models derived using additional 24-h dietary recall data in a calibration sample and the respective exposure-disease model covariates. Markers of inflammation, measured at baseline, included IL-6 (n=1405), CRP (n=1387), and fibrinogen (n=1340); markers of arterial stiffness, measured approximately 19 months post-baseline, were available in a subset of participants and included augmentation index (n=180), pulse wave velocity (n=184), and brachial distensibility (n=177).

RESULTS

Mean (SD) T1D duration was 47.9 (43.2) months; 12.5% of participants were obese. Mean (SD) ME-adjusted fiber intake was 15 (2.8) g/day. In multivariable analyses, fiber intake was not associated with inflammation or arterial stiffness.

CONCLUSION

Among youth with T1D, fiber intake does not meet recommendations and is not associated with measures of systemic inflammation or vascular stiffness. Further research is needed to evaluate whether fiber is associated with these outcomes in older individuals with T1D or among individuals with higher intakes than those observed in the present study.

Effects of anthracyclines on aortic distensibility in patients with lymphomas: a prospective study

INTRODUCTION

Anthracyclines have been widely used in the treatment of haematological malignancies. Their major adverse effect is cardiomyopathy, but their effect on vascular elasticity has not been completely elucidated. The aim of the present study was to investigate the effects of anthracyclines on aortic elastic properties in patients with lymphomas.

METHODS

We studied 70 patients with lymphomas, 37 males (52.9%), age 44 ± 19 years, who were free of any cardiorenal or metabolic comorbidity. Forty-five (64.2%) had a non-Hodgkin lymphoma and the remainder a Hodgkin lymphoma. All participants were evaluated with echocardiography, laboratory and clinical examinations to estimate cardiac function and aortic elasticity in the following study phases: before the administration of anthracyclines (i.e. baseline), after three months, and after the end of treatment.

RESULTS

A progressive decrease in aortic distensibility was observed over the three phases of the study (2.48 ± 0.2 vs. 2.41 ± 0.18, vs. 2.36 ± 0.23, 10(-6).dyn(-1).cm(2); p<0.016 for all comparisons). A statistically significant decrease in left ventricular ejection fraction was also observed between baseline and final follow up. Significant negative predictors of aortic distensibility at final follow up were baseline age, systolic blood pressure, left atrial diameter, and left ventricular ejection fraction.

CONCLUSIONS

Anthracycline therapy decreases aortic distensibility in patients with lymphomas.

Remodeling of aorta extracellular matrix as a result of transient high oxygen exposure in newborn rats: implication for arterial rigidity and hypertension risk

Neonatal high-oxygen exposure leads to elevated blood pressure, microvascular rarefaction, vascular dysfunction and arterial (aorta) rigidity in adult rats. Whether structural changes are present in the matrix of aorta wall is unknown. Considering that elastin synthesis peaks in late fetal life in humans, and early postnatal life in rodents, we postulated that transient neonatal high-oxygen exposure can trigger premature vascular remodelling. Sprague Dawley rat pups were exposed from days 3 to 10 after birth to 80% oxygen (vs. room air control) and were studied at 4 weeks. Blood pressure and vasomotor response of the aorta to angiotensin II and to the acetylcholine analogue carbachol were not different between groups. Vascular superoxide anion production was similar between groups. There was no difference between groups in aortic cross sectional area, smooth muscle cell number or media/lumen ratio. In oxygen-exposed rats, aorta elastin/collagen content ratio was significantly decreased, the expression of elastinolytic cathepsin S was increased whereas collagenolytic cathepsin K was decreased. By immunofluorescence we observed an increase in MMP-2 and TIMP-1 staining in aortas of oxygen-exposed rats whereas TIMP-2 staining was reduced, indicating a shift in the balance towards degradation of the extra-cellular matrix and increased deposition of collagen. There was no significant difference in MMP-2 activity between groups as determined by gelatin zymography. Overall, these findings indicate that transient neonatal high oxygen exposure leads to vascular wall alterations (decreased elastin/collagen ratio and a shift in the balance towards increased deposition of collagen) which are associated with increased rigidity. Importantly, these changes are present prior to the elevation of blood pressure and vascular dysfunction in this model, and may therefore be contributory.

Effect of Rg3-enriched Korean red ginseng (Panax ginseng) on arterial stiffness and blood pressure in healthy individuals: a randomized controlled trial

Ginsenoside Rg3, present in steamed ginseng (Panax Ginseng C.A. Meyer), is thought to be a potent modulator of vascular function. Our objective was to clinically evaluate acute effects of ginsenoside Rg3-enriched Korean red ginseng (Rg3-KRG) on measures of arterial stiffness and peripheral and central blood pressure (BP) parameters in healthy volunteers. Using a double-blind, randomized, crossover design, 23 individuals (9 males:14 females; age, 25 ± 2 years; body mass index, 22 ± 0.6 kg/m(2); systolic BP/diastolic BP, 113 ± 3/70 ± 2 mm Hg) were administered 400-mg Rg3-KRG extract or 400-mg wheat bran control on two separate visits with a 7-day washout period. Aortic augmentation index and central BP were measured using applanation tonometry by radial pulse wave analysis, and peripheral BP was evaluated oscillometrically. Measurements were taken at baseline and at 1, 2, and 3 hours after intervention. Compared with control, there were significant reductions in augmentation index (-4.3 ± 8.9%, P = .03), central (-4.8 ± 6.8 mm Hg, P = .01) and brachial mean arterial pressure (-4.4 ± 6.6 mm Hg, P = .01), central systolic (-5.0 ± 7.9 mm Hg, P = .01) and diastolic BP (-3.9 ± 6.6 mm Hg, P = .01), and brachial systolic (-4.4 ± 10.0 mm Hg, P = .048) and diastolic BP (-3.6 ± 6.4 mm Hg, P = .01) at 3 hours after intervention compared with control. This study is the first to demonstrate Rg3-KRG extract acutely lowers central and peripheral arterial pressures in healthy adults. Further clinical evaluation is desired to quantify efficacy in higher risk individuals and in long-term settings.

Regular cocaine use is associated with increased systolic blood pressure, aortic stiffness and left ventricular mass in young otherwise healthy individuals

BACKGROUND

The cardiovascular impact of cocaine use in otherwise healthy individuals who consider themselves 'social' users is not well established.

METHODS/RESULTS

Twenty regular cocaine users and 20 control subjects were recruited by word-of-mouth. Cardiovascular magnetic resonance was performed to assess cardiac and vascular structure and function. Cocaine users had higher systolic blood pressure compared to non-users (134±11 vs 126±11 mmHg, p = 0.036), a finding independent of age, body surface area, smoking and alcohol consumption. Cocaine use was associated with increased arterial stiffness - reflected by reduced aortic compliance (1.3±0.2 vs 1.7±0.5 cm2×10-2.mmHg-1, p = 0.004), decreased distensibility (3.8±0.9 vs 5.1±1.4 mmHg-1.10-3, p = 0.001), increased stiffness index (2.6±0.6 vs 2.1±0.6, p = 0.005), and higher pulse wave velocity (5.1±0.6 vs 4.4±0.6 m.s-1, p = 0.001). This change in aortic stiffness was independent of vessel wall thickness. Left ventricular mass was 18% higher in cocaine users (124±25 vs 105±16 g, p = 0.01), a finding that was independent of body surface area, and left atrial diameter was larger in the user group than controls (3.8±0.6 vs 3.5±0.3 cm, p = 0.04). The increased left ventricular mass, systolic blood pressure and vascular stiffness measures were all associated with duration and/or frequency of cocaine use. No late gadolinium enhancement or segmental wall motion abnormalities were seen in any of the subjects.

CONCLUSIONS

Compared with the non-user control cohort, cocaine users had increased aortic stiffness and systolic blood pressure, associated with greater left ventricular mass. These measures are all well known risk factors for premature cardiovascular events, highlighting the dangers of cocaine use, even in a 'social' setting, and have important public health implications.

Allopurinol is an independent determinant of improved arterial stiffness in chronic kidney disease: a cross-sectional study

Background

Arterial stiffness is increased in patients with CKD and is a powerful predictor of cardiovascular morbidity and mortality. Use of the xanthine oxidase inhibitor allopurinol has been shown to improve endothelial function, reduce left ventricular hypertrophy and possibly improve cardiovascular outcome. We explored the relationship between use of allopurinol and arterial stiffness in patients with chronic kidney disease (CKD).

Methods

Cross-sectional observational study of 422 patients with CKD with evidence of, or at high risk of, renal disease progression. Arterial stiffness was determined by carotid-femoral pulse wave velocity (PWV).

Results

The mean age was 63±16 years, median estimated glomerular filtration rate was 25 (interquartile range: 19–31) ml/min/1.73 m² and mean PWV was 10.2±2.4 m/s. Seventy-seven patients (18%) were receiving regular allopurinol, 61% at a dose of 100 mg/day (range: 50–400 mg/day). Patients receiving allopurinol had significantly lower peripheral pulse pressure, central pulse pressure, central systolic blood pressure, serum uric acid level tissue advanced glycation end product levels but comparable high-sensitivity C-reactive protein levels. Use of allopurinol was associated with lower PWV. After adjusting for age, gender, ethnicity, tissue advanced glycation end product level, peripheral pulse pressure, smoking pack years, presence of diabetes mellitus and use of angiotensin converting enzyme inhibitor or angiotensin II receptor blocker, the use of allopurinol remained a significant independent determinant of PWV (mean difference: −0.63 m/s; 95% CI, −0.09 to −1.17 m/s, p = 0.02).

Conclusion

In patients with CKD, use of allopurinol is independently associated with lower arterial stiffness. This study provides further justification for a large definitive randomised controlled trial examining the therapeutic potential of allopurinol to reduce cardiovascular risk in people with CKD.