ADRA2B gene insertion/deletion polymorphism and artery compliance

Background The ADRA2B gene insertion/deletion （I/D） polymorphism is associated with various cardiovascular and metabolic phenotypes. Large （C1） and small （C2） artery compliance, assessed by pulse wave analysis, is considered as sensitive markers or risk factors for cardiovascular disease. Therefore whether the ADRA2B I/D polymorphism is associated with CI and C2 need to be investigated. Methods A total of 227 men and 243 women were enrolled in a Chinese family-based study. C1 and C2 were measured by pulse wave analysis. ADRA2B genotypes were determined by polymerase chain reaction. Statistical methods included generalized estimation equations and quantitative transmission disequilibrium test. Results The II （31.9%）, ID （46.8%） and DD （21.3%） genotype frequencies were in Hardy-Weinberg equilibrium （P = 0. 73 ）. The covariates selected by stepwise regression for C1 and C2 were age, systolic pressure and gender. The population based association analysis showed that C1 and C2 were not associated with ADRA2B genotype both before （C1 ： P =0. 28; C2： P =0. 27） and after （C1 ： P =0. 58; C2： P =0. 18） the adjustment. The family-based analyses of 128 informative offspring showed that transmission of the D-allele was not associated with C1 orC2, both before （CI： P=0.42; C2： P=0.85） and after （CI： P=0.31; C2： P= 0. 82） the adjustment. Conclusion The study do not support that the ADRA2B gene I/D polymorphism has a major gene effect on C1 or C2 in the Chinese population of current sample size.

Reduced Arterial Compliance Associated with Metabolic Syndrome in Chinese Children and Adolescents

Objective To explore the metabolic syndrome and its association with arterial compliance in Chinese children and adolescents. Methods 337 participants aged 6 to 18 years with males accounted for 55.8% were grouped according to their traits of metablic syndrome. Anthropometry, blood pressure, fasting plasma glucose, insulin and serum lipid profile were measured. Homeostasis model was assessed and insulin resistance （HOMA-IR） index was measured and calculated for estimating individual insulin resistance. Arterial compliance was also measured using digital pulse wave analyzing method （Micro medical, London）, and stiffness index was calculated. Results The stiffness index in participants with metablic syndrome was significant higher than that in participants with no riskof metablic syndrome [（7.69±1.63） vs （6.25±0.86） m/s, P〈0.01] and stiffness index and HOMA-IR were progressively increased with the increase of traits of metablic syndrom （P for linear trend 〈0.001）. After gender, age, and pubertal development were adjusted, both traits of metablic syndrome and HOMA-IR were correlated positively with stiffness index （both P〈0.05）. Conclusion The clustering of metablic syndrome was closely associated with risk at increased arterial stiffness in Chinese children and adolescents. It was suggested that arterial compliance assessment of children and adolescents might be an important measure for prevention of cardiovascular diseases.

Clinical Significance of Evaluating Antihyperten-sive Effect with Arterial Compliance

Objective To evaluate the clinical significance of antihypertensive effect with arterial compliance. Methods In males, 72 cases were control group, 35 cases were EH-controlled, and 35 cases were EH-uncontrolled groups. Blood pressure and arterial compliance (Cl and C2) were detected by HDI DO-2020. Results In the EH-uncontrolled group,the values of systolic blood pressure ( SBP ) , diastolic blood pressure (DBF) , mean arterial pressure (MAP ) , and pulse pressure (PP) were significantly higher than those of the control and the EH-controlled groups (P<0. 01) , however,there was no difference between the control and the EH-controlled groups. In the EH-uncon-trolled group,the values of Cl and C2 were lower than those of both the control and the EH-controlled groups (P<0. 01) ,again,wtih no difference between the control and the EH-controlled groups. Conclusion Arterial compliance (Cl and C2) measurements may serve as a sensitive indicator of evaluating antihypertensive effect.

Liver cirrhosis and arterial hypertension

Characteristic findings in patients with cirrhosis are vasodilatation with low overall systemic vascular resistance, high arterial compliance, increased cardiac output, secondary activation of counter-regulatory systems （renin-angiotensin-aldosterone system, sympathetic nervous system, release of vasopressin）, and resistance to vasopressors. The vasodilatory state is mediated through adrenomedullin, calcitonin generelated peptide, nitric oxide, and other vasodilators, and is most pronounced in the splanchnic area. This constitutes an effective （although relative） counterbalance to increased arterial blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension （essential, secondary） may become normotensive during the development of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most likely includes the combination of vasodilatation and vasoconstriction in parallel.

Baroreflex dysfunction in chronic kidney disease

Chronic kidney disease （CKD） patients have high cardiovascular mortality and morbidity. The presence of traditional and CKD related risk factors results in exaggerated vascular calcification in these patients. Vascular calcification is associated with reduced large arterial compliance and thus impaired barorefex sensi-tivity （BRS） resulting in augmented blood pressure （BP） variability and hampered BP regulation. Barorefex plays a vital role in short term regulation of BP. This review discusses the normal barorefex physiology, methods to assess baroreflex function, its determinants along with the prognostic significance of assessing BRS in CKD patients, available literature on BRS in CKD patients and the probable patho-physiology of barorefex dysfunction in CKD.

Associations of blood pressure and arterial compliance with occupational noise exposure in female workers of textile mill

Background There are few studies on the arterial compliance of noise exposure. The purpose of this study was to understand the relationship between hearing loss, blood pressure and arterial compliance of female workers who exposed to occupational noise in a textile mill. Methods The noise levels in the workplace were measured with a HS6288 sound level meter. Cumulated noise exposure （CNE） was calculated according to the noise intensity and the exposure period. Hearing ability and arterial compliance were measured in 618 noise exposed workers. The database was set up with EpiData and the statistical analysis was performed with SAS software 9.1.3. Results The noise levels were 80.1dB（A） to 113.5dB（A）, of which the levels at 92.5% of the noise monitoring sites were over the national standard. The incidence of high frequency hearing loss （HFHL） was 24.43% and language frequency hearing impairment （LFHI） was 0.81%. The incidence of hypertension was 7.93%. Both systolic blood pressure （SBP） and diastolic blood pressure （DBP） in the high frequency hearing loss group were significantly higher than those in the normal hearing group （P〈0.05）, while C1 （large artery compliance） and C2 （small artery compliance） were significantly lower （P〈0.05）. The high frequency hearing threshold （HFHT） of the hypertension group was significantly higher than in the normal blood pressure group （P〈0.05）, while C1 and C2 were significantly lower （P〈0.05）.C1 and C2 had a negative correlation with HFHT, SBP, DBP, mean of arterial pressure （MAP）, pulse pressure （PP） and pulse rate （PR） （P〈0.05）. The multiple regression analyses showed that blood pressure and PR were the main influencing factors on C1 and C2. LFHT was an influence on C2 and HFHT on C1. Conclusions Textile mill noise pollution is very serious and has an obvious influence on worker＇s auditory function. The female workers with low artery compliance or with high blood pressure might be suffering from hearing loss; those with noise induced hearing loss might be suffering from hypertension if she is constantly exposed to loud industrial noise.

Decreased small arterial compliance with increased serum vascular endothelial growth factor-A and circulating endothelial progenitor cell in dilated cardiomyopathy

Background Evidence showed that both myocardium and blood vessels were damaged in dilated cardiomyopathy （DCM）. However, the changes in arterial compliance, serum cytokines and circulating endothelial progenitor cells （EPC）, and their correlations remain unknown. Methods Sixty-five DCM patients and 49 healthy volunteers were studied. Both large artery compliance （C1） and small artery compliance （C2） were measured with the CVProfUor DO-2020. Quantitative enzyme-linked immunosorbent assays （ELISAs） were used to measure the levels of vascular endothelial growth factor-A （VEGF-A） and VEGF receptor 2 （VEGF-R2）. Circulating EPC was assessed by EPC colony-forming assays and flow cytometry （CD133^＋/CD34^＋cells）. Phagocytized Dil-acLDL and binded FITC-UEA-I were used to analyze endothelial lineage marker expression by immunofluorescence. Results Although C2 was markedly lower in DCM patients than in control group （（3.8±1.8） ml/mmHg × 100 vs （5.0±2.2） ml/mmHg × 100, P〈0.0001）, there was no statistically significant difference in C1 between the two groups （P〉0.05）. Levels of VEGF-A, the numbers of colony-forming units （CFU） and the fractions of EPC were obviously higher in DCM patients than in control group （（127.6±139.5） pg/ml vs （58.8±42.9） pg/ml, P〈0.0001; （2.5±1.5）% vs （0.5±0.3）%, P〈0.05; 23.5±12.8 vs 10.8±7.4, P〈0.01, respectively） and however, there was no significant difference in VEGF-R2 between two groups （P〉0.05）. LgVEGF-A was positively correlated with the number of EPC-CFU （r=-0.435; P〈0.05） and inversely correlated with C2 （r=-0.543; P〈0.001） in DCM patients. Conclusions The reduction of C2, a sensitive marker reflecting endothelial dysfunction, was observed in DCM patients and closely related to the increase in serum VEGF-A.

Association of metabolic syndrome with arterial compliance in children and adolescents

The association of metabolic syndrome(MS)with arterial compliance in children and adolescents was explored.337 subjects(188 men and 149 women)aged 6–18(10.95±3.01)years,out of“Beijing Child Metabolic Syndrome Study”,were divided into three case groups(one component,two components,three&more components of MS)and one control group based on the Cook’s MS definition in children and adolescents.Measurements including anthropometry,blood pressure,fasting plasma glucose and insulin,serum lipid profile were done.Homeostasis model assessment for insulin resistance(HOMA-IR)index was calculated for estimating individual insulin resistance.Arterial compliance was measured using digital pulse wave analyzing method from the pulse trace machine(Micro medical,London),and then the stiffness index(SI)was determined.The mean value of SI in MS group was significant higher than that in control group[(7.69±1.63)vs(6.25±0.86)m/s,P<0.01].With the increase of the clustering of MS components,SI and HOMA-IR were gradually increased.After taking account of gender,age and pubertal development,the partial correlation analysis showed that the amount of components of MS and HOMA-IR were positively correlated with SI(both P values were less than 0.05).The arterial compliance of MS group was significantly lowered in children and adolescents,and with the increase of the clustering of MS components,arterial compliance was gradually decreased.It was suggested that arterial compliance assessment in children and adolescents was important for early prevention of cardiovascular diseases.

Lumped Parameter Outflow Models for 1-D Blood Flow Simulations:Effect on Pulse Waves and Parameter Estimation

Several lumped parameter,or zero-dimensional(0-D),models of the microcirculation are coupled in the time domain to the nonlinear,one-dimensional(1-D)equations of blood flow in large arteries.A linear analysis of the coupled system,together with in vivo observations,shows that:(i)an inflow resistance that matches the characteristic impedance of the terminal arteries is required to avoid non-physiological wave reflections;(ii)periodic mean pressures and flow distributions in large arteries depend on arterial and peripheral resistances,but not on the compliances and inertias of the system,which only affect instantaneous pressure and flow waveforms;(iii)peripheral inertias have a minor effect on pulse waveforms under normal conditions;and(iv)the time constant of the diastolic pressure decay is the same in any 1-D model artery,if viscous dissipation can be neglected in these arteries,and it depends on all the peripheral compliances and resistances of the system.Following this analysis,we propose an algorithm to accurately estimate peripheral resistances and compliances from in vivo data.This algorithm is verified against numerical data simulated using a 1-D model network of the 55 largest human arteries,in which the parameters of the peripheral windkessel outflow models are known a priori.Pressure and flow waveforms in the aorta and the first generation of bifurcations are reproduced with relative root-mean-square errors smaller than 3%.