Cigarette smoking and hypertension Virdis, A; Giannarelli, C; Neves, M Fritsch ...
Current pharmaceutical design,
08/2010, Letnik:
16, Številka:
23
Journal Article
Recenzirano
Cigarette smoking is a powerful cardiovascular risk factor and smoking cessation is the single most effective lifestyle measure for the prevention of a large number of cardiovascular diseases. ...Impairment of endothelial function, arterial stiffness, inflammation, lipid modification as well as an alteration of antithrombotic and prothrombotic factors are smoking-related major determinants of initiation, and acceleration of the atherothrombotic process, leading to cardiovascular events. Cigarette smoking acutely exerts an hypertensive effect, mainly through the stimulation of the sympathetic nervous system. As concern the impact of chronic smoking on blood pressure, available data do not put clearly in evidence a direct causal relationship between these two cardiovascular risk factors, a concept supported by the evidence that no lower blood pressure values have been observed after chronic smoking cessation. Nevertheless, smoking, affecting arterial stiffness and wave reflection might have greater detrimental effect on central blood pressure, which is more closely related to target organ damage than brachial blood pressure. Hypertensive smokers are more likely to develop severe forms of hypertension, including malignant and renovascular hypertension, an effect likely due to an accelerated atherosclerosis.
Network-controlled device-to-device (D2D) communication allows cellular users to communicate directly, i.e., without passing through the eNodeB, while the latter retains control over resource ...allocation. This allows the same time–frequency resources to be allocated to spatially separated D2D flows simultaneously, thus increasing the cell throughput. This paper presents a framework for: (1) selecting which communications should use the D2D mode, and when, and (2) allocating resources to D2D and non-D2D users, exploiting reuse for the former. We show that the two problems, although apparently similar, should be kept separate and solved at different timescales in order to avoid problems, such as excessive packet loss. We model both as optimization problems, and propose a heuristic solution to the second, which must be solved at millisecond timescales. Simulation results show that our framework is practically viable, it avoids the problem of packet losses, increases throughput and reduces delays.
Subclinical hypothyroidism (sHT) is associated with dyslipidemia and enhanced cardiovascular risk. We assessed carotid artery intima-media thickness (IMT, high-resolution ultrasonography) and ...lipoprotein profile in 45 sHT patients (aged 37 ± 11 yr) at baseline and after 6 months of randomized, placebo-controlled l-T4 replacement. In comparison with 32 age- and sex-matched controls, sHT patients had elevated total and low-density lipoprotein (LDL) cholesterol and ApoB levels (P = 0.002, P = 0.0007, and P = 0.01, respectively) and higher mean-IMT values (P < 0.0001). In stepwise regression analysis, mean-IMT was positively related (r2 = 0.71, P < 0.0001) to age, TSH, and LDL cholesterol. l-T4 replacement significantly reduced both total and LDL cholesterol (P < 0.0001 for both) and mean-IMT (by 11%, P < 0.0001). The decrement in IMT was directly related to the decrements of both total cholesterol and TSH (P = 0.02 and P = 0.0001, respectively). We conclude that early carotid artery wall alterations are present in sHT patients. Whether such IMT increase is related to an early atherosclerotic involvement of the arterial wall cannot be clearly decided on the basis of the present results. However, the fact that l-T4 replacement therapy was able to improve both the atherogenic lipoprotein profile and intima-media thickening suggests that lipid infiltration of arterial wall may represent a major mechanism underlying IMT increase in subclinical hypothyroidism.
We have developed an atom interferometer providing a full inertial base. This device uses two counterpropagating cold-atom clouds that are launched in strongly curved parabolic trajectories. Three ...single Raman beam pairs, pulsed in time, are successively applied in three orthogonal directions leading to the measurement of the three axis of rotation and acceleration. In this purpose, we introduce a new atom gyroscope using a butterfly geometry. We discuss the present sensitivity and the possible improvements.
Abstract The endothelium plays a primary role in the modulation of vascular tone and structure, through production of the relaxing factor nitric oxide, which acts by protecting the vessel wall from ...the development of atherosclerosis and thrombosis. A dysfunctioning endothelium, characterized by reduced nitric oxide availability, can be a promoter of atherosclerosis. Ageing is a well-documented cardiovascular risk factor. One of the possible physiopathological mechanisms whereby increasing age may lead to cardiovascular damage is the promotion of endothelial dysfunction. In humans, age-related impairment in endothelium-dependent vasodilation has been well documented in different vascular districts and involves the impairment of nitric oxide activity secondary to oxidative stress generation. Regular physical training is an important non-pharmacological intervention which protects the vascular endothelium from ageing-related alterations and ameliorates the cardiovascular risk profile among the elderly population.
OBJECTIVE:Serum uric acid (SUA) is a predictor of cardiovascular disease (CVD), but its levels that discriminate risk for CVD and mortality remain unknown. We used a large Italian population ...comprising >30000 subjects to assess the threshold of SUA that increases the risk of total and CVD mortality.
DESIGN AND METHOD:The URic Acid Right for heArt Health (URRAH) study is a regional-basis multicentre cohort study collecting data from prospective studies and databases from different hypertension centres. Total mortality included mortality for any causes, cardiovascular mortality as death due to fatal myocardial infraction, stroke or heart failure. Multivariate dichotomic logistic and Cox regression models were used to confirm the relationship between SUA and mortality both from cardiovascular and any causes, while ROC curves were used to identify the threshold of SUA that better discriminated people at higher or lower mortality risk.
RESULTS:22.275 subjects had SUA and mortality information. Logistic regression identified a direct and strong association between SUA and an increased risk of total (OR 1.176, 95%CI 1.127–1.227) and CVD (OR 1.147, 95%CI 1.093–1.203) mortality, independently of other confounders. Cox models confirmed an independent association between SUA and any causes, and CVD mortality. ROC curve analysis identified a cut-off value od SUA (4.79 mg/dL (95%CI 4.7–5.4 mg/dl) able to discriminate total mortality status, and a different one (5.60 mg/dL (95%CI 5.09–5.89 mg/dl) able to identify CVD mortality status. Multivariate Cox analysis adjusted for confounders confirmed that subjects with SUA >4.79 mg/dl had a significantly higher total mortality (HR 1.293, 95%CI 1.181–1.416) compared to those with SUA < 4.79 mg/dl. Similarly, subjects with SUA >5.60 mg/dl had a significantly higher CVD mortality (HR 1.428, 95%CI 1.273–1.600) than those with SUA < 5.60 mg/dl after adjustment for the same confounders.
CONCLUSIONS:Levels of SUA that increase the risk of total and CVD mortality are significantly lower than those commonly used for the definition of hyperuricemia in clinical practice. Our data provide the first large evidence of a level of “cardiovascular” SUA that might be used in clinical practice to identify subjects at greater risk of total and CVD mortality.
Abstract The endothelium plays a pivotal role in maintaining vascular homeostasis, mainly by the production of the relaxing factor nitric oxide, which protects the vessel wall from the development of ...atherosclerosis. Aging is a powerful cardiovascular risk factor, associated with endothelial dysfunction both in normotensive subjects and in hypertensive patients. Premenopausal normotensive women are protected against the deleterious effect of aging on endothelial function, and age-related impairment of endothelial function is attenuated in premenopausal hypertensive women. This protective effect on endothelium seems to be mediated by endogenous estrogen, which preserves nitric oxide availability by activating the l -arginine-NO pathway in normotensive women and by inhibiting reactive oxygen species generation. Whether endogenous androgen may modulate endothelial function and the mechanisms involved are still unsolved issues, since data concerning the effect of testosterone on endothelium are scanty and contradictory.
OBJECTIVE:Essential hypertensive patients (EH) are characterized by endothelial dysfunction caused by a reduced nitric oxide (NO) availability due to reactive oxygen species excess and low-grade ...inflammatory condition. Ghrelin is a recently identified growth hormone-releasing peptide, with recognized cardiovascular actions. Possible effects on endothelial dysfunction have been never investigated in EH. In this study we evaluated whether exogenous ghrelin can improve endothelial dysfunction in the forearm microcirculation of untreated mild-moderate EH.
DESIGN AND METHOD:In 9 EH (51.8 ± 8.1 yrs) and 9 normotensive subjects (NS, 50.5 ± 3.5 yrs), we studied the forearm blood flow (FBF, strain-gauge plethysmography) response to intrabrachial acetylcholine (ACh, 0.15–15 mg/100 ml/min) with and without NO synthase blockade by L-NMMA (100 μg/100 ml/min), or the antioxidant vitamin (Vit) C (8 mg/100 ml/min). The protocol was repeated under exogenous ghrelin intra-arterial infusion (200 ng/min, 30’ pre-infusion).
RESULTS:In NS, the maximal vasodilation (VD) to ACh (480 ± 20%) was inhibited by L-NMMA (292 ± 22, -39 ± 7%; P < 0.001) and unchanged by Vit C (482 ± 34%). Ghrelin failed to modify these vascular responses. In EH, VD to ACh was blunted vs NS (337 ± 45%; P < 0.001) and resistant to L-NMMA (313 ± 32, -7 ± 3%). Vit C increased the response to ACh (509 ± 57%; P < 0.01 vs ACh alone) and restored the inhibiting effect of L-NMMA (332 ± 42, -34 ± 8%; P < 0.001). Ghrelin, while not modifying the basal FBF, it increased (P < 0.001) the VD to ACh (448 ± 55) and restored the inhibitory effect of L-NMMA on ACh (355 ± 43, -20 ± 6%; P < 0.001). Vit C only slightly improved VD to ACh under ghrelin infusion (486 ± 45%). In EH ghrelin significantly (P < 0.05) decreased plasma venous malodialdehyde (from 6.9 ± 1.5 to 5.2 ± 1.0 μmol/L), lipoperoxides (from 9.1 ± 1.9 to 6.6 ± 2.3 μmol/L) and IL-6 (from 11.1 ± 0.6 to 9.3 ± 1.0 pg/mL) and increased plasma antioxidant capacity (from 407 ± 109 to 630 ± 97 mmol/L). Response to sodium nitroprusside was similar between EH and NS and not affected by ghrelin.
CONCLUSIONS:Exogenous ghrelin is able to increase endothelial dysfunction by restoring NO availability in the forearm microcirculation of EH, an effect probably determined by antioxidant and/or anti-inflammatory activities.
The rapid increasing prevalence of obesity worldwide represents a serious health hazard. Obesity predisposes to increased risk for diabetes, hypertension, renal failure. Direct mechanisms link ...visceral adiposity and the atherosclerosis process through the action of adipose-derived proinflammatory cytokines. In particular, hypertension can be considered the most important cardiovascular risk factor linking obesity to the development of cardiovascular disease. Obesity among children and adolescents has also reaching epidemic proportions in the industrialized world. Childhood obesity strongly predisposes to cardiovascular adult mortality. Recent reports documented a tracking of blood pressure from childhood to adulthood and obesity occurring in young age plays a crucial pathogenic role. Indeed, fighting overweight and obesity in the pediatric and adolescent age may prevent the occurrence of adults with hypertension and cardiovascular disease. The main strategies for prevention and treatment of overweight and obesity in childhood, which need to involve community, school and family, are the promotion of lifestyle interventions, including as a correct dietary approach, rich in fruit and vegetables and low-fat dairy products, and physical activity.
PDF
