Physical activity reduces genetic susceptibility to increased central systolic pressure augmentation: a study of female twins

CaMKII activity and metabolic imbalance-related neurological diseases: Focus on vascular dysfunction, synaptic plasticity, amyloid beta accumulation, and lipid metabolism

Metabolic syndrome (MetS) is characterized by insulin resistance, hyperglycemia, excessive fat accumulation and dyslipidemia, and is known to be accompanied by neuropathological symptoms such as memory loss, anxiety, and depression. As the number of MetS patients is rapidly increasing globally, studies on the mechanisms of metabolic imbalance-related neuropathology are emerging as an important issue. Ca2+/calmodulin-dependent kinase II (CaMKII) is the main Ca2+ sensor and contributes to diverse intracellular signaling in peripheral organs and the central nervous system (CNS). CaMKII exerts diverse functions in cells, related to mechanisms such as RNA splicing, reactive oxygen species (ROS) generation, cytoskeleton, and protein-protein interactions. In the CNS, CaMKII regulates vascular function, neuronal circuits, neurotransmission, synaptic plasticity, amyloid beta toxicity, lipid metabolism, and mitochondrial function. Here, we review recent evidence for the role of CaMKII in neuropathologic issues associated with metabolic disorders.

Modifiable Clinical Correlates of Vascular Health in Children and Adolescents with Dyslipidemia

Atherosclerosis promoting cardiovascular disease risk factors (CVDrf) are highly prevalent among youth in the U.S. Determining which standard modifiable clinical measures (SMCMs) has the greatest impact on vascular structure and function is valuable for the health care provider to help identify children at highest risk. The aim of this study was to determine modifiable outpatient clinical predictors of vascular health in youth with CVDrf. Children and adolescents with CVDrf (n = 120, 13.1 ± 1.9 years, 49% female) were recruited from a pediatric preventive cardiology clinic. The SMCMs included BMI z-score, waist-to-height ratio (WTHR), lipid panel, hemoglobin A1c, blood pressure (BP), presence of tobacco smoke exposure, and presence of hypertriglyceridemic waist (HTW) phenotype (triglycerides ≥ 110 mg/dL and waist circumference ≥ 90 percentile). Vascular function and structure were measured with pulse wave velocity (PWV), central systolic BP (CSP), augmentation index (AIx), and carotid artery intima-media thickness (cIMT). Sex and height specific z-scores for PWV, CSP, and cIMT were used. Multiple linear regression with backwards selection identified SMCMs which strongly predicted vascular function and structure. Among SMCMs, WTHR and HTW were the most frequent predictors of vascular function (PWV: R² = 0.32; CSP: R² = 0.35; AIx R² = 0.13). Other predictors of vascular function included hemoglobin A1C, BP, and BMI z-score. Systolic BP and LDL cholesterol were predictors of vascular structure (cIMT: R² = 0.14). The strongest predictors of vascular health in youth with CVDrf were related to measures of central obesity. Targeting these SMCM in lieu of vascular testing in outpatient clinic setting may be practical to identify children and adolescents at greatest risk for CVD.

Insulin resistance is associated with subclinical vascular disease in humans

Insulin resistance is associated with subclinical vascular disease that is not justified by conventional cardiovascular risk factors, such as smoking or hypercholesterolemia. Vascular injury associated to insulin resistance involves functional and structural damage to the arterial wall that includes impaired vasodilation in response to chemical mediators, reduced distensibility of the arterial wall (arterial stiffness), vascular calcification, and increased thickness of the arterial wall. Vascular dysfunction associated to insulin resistance is present in asymptomatic subjects and predisposes to cardiovascular diseases, such as heart failure, ischemic heart disease, stroke, and peripheral vascular disease. Structural and functional vascular disease associated to insulin resistance is highly predictive of cardiovascular morbidity and mortality. Its pathogenic mechanisms remain undefined. Prospective studies have demonstrated that animal protein consumption increases the risk of developing cardiovascular disease and predisposes to type 2 diabetes (T2D) whereas vegetable protein intake has the opposite effect. Vascular disease linked to insulin resistance begins to occur early in life. Children and adolescents with insulin resistance show an injured arterial system compared with youth free of insulin resistance, suggesting that insulin resistance plays a crucial role in the development of initial vascular damage. Prevention of the vascular dysfunction related to insulin resistance should begin early in life. Before the clinical onset of T2D, asymptomatic subjects endure a long period of time characterized by insulin resistance. Latent vascular dysfunction begins to develop during this phase, so that patients with T2D are at increased cardiovascular risk long before the diagnosis of the disease.

Lack of exercise is a major cause of chronic diseases

Chronic diseases are major killers in the modern era. Physical inactivity is a primary cause of most chronic diseases. The initial third of the article considers: activity and prevention definitions; historical evidence showing physical inactivity is detrimental to health and normal organ functional capacities; cause versus treatment; physical activity and inactivity mechanisms differ; gene-environment interaction (including aerobic training adaptations, personalized medicine, and co-twin physical activity); and specificity of adaptations to type of training. Next, physical activity/exercise is examined as primary prevention against 35 chronic conditions [accelerated biological aging/premature death, low cardiorespiratory fitness (VO2max), sarcopenia, metabolic syndrome, obesity, insulin resistance, prediabetes, type 2 diabetes, nonalcoholic fatty liver disease, coronary heart disease, peripheral artery disease, hypertension, stroke, congestive heart failure, endothelial dysfunction, arterial dyslipidemia, hemostasis, deep vein thrombosis, cognitive dysfunction, depression and anxiety, osteoporosis, osteoarthritis, balance, bone fracture/falls, rheumatoid arthritis, colon cancer, breast cancer, endometrial cancer, gestational diabetes, pre-eclampsia, polycystic ovary syndrome, erectile dysfunction, pain, diverticulitis, constipation, and gallbladder diseases]. The article ends with consideration of deterioration of risk factors in longer-term sedentary groups; clinical consequences of inactive childhood/adolescence; and public policy. In summary, the body rapidly maladapts to insufficient physical activity, and if continued, results in substantial decreases in both total and quality years of life. Taken together, conclusive evidence exists that physical inactivity is one important cause of most chronic diseases. In addition, physical activity primarily prevents, or delays, chronic diseases, implying that chronic disease need not be an inevitable outcome during life.

Habitual exercise and blood pressure: age dependency and underlying mechanisms

BACKGROUND

Regular exercise is associated with a reduction in cardiovascular risk, but the precise mechanisms responsible are unknown. The aim of the current study was to examine the relationship between regular exercise, aortic stiffness, and wave reflections, and to determine whether this relationship differs by age.

METHODS

Younger (<30 years) and older (>50 years) individuals, who were either sedentary or undertook regular aerobic exercise, were drawn from the Anglo-Cardiff Collaborative Trial population. This yielded 1,036 individuals, all of whom were nonsmokers, and were free of cardiovascular disease and medication. All individuals undertook a detailed lifestyle and medical history questionnaire including details of physical activity. Brachial and central blood pressure, together with aortic stiffness, wave reflections, cardiac output, and peripheral vascular resistance were assessed in all individuals.

RESULTS

In younger individuals, regular exercise was associated with lower diastolic blood pressure but elevated pulse pressure. In contrast, both systolic and pulse pressure were lower in older active individuals, compared with their sedentary counterparts. Moreover, regular exercise was associated with lower wave reflections and peripheral vascular resistance in younger individuals, but lower large artery stiffness in older individuals.

CONCLUSIONS

These data suggest that regular exercise is associated with a beneficial vascular profile. However, this differs between younger and older individuals such that the smaller preresistance and resistance vessels are involved in younger individuals whereas the large elastic arteries are involved in older individuals. Despite these differential findings, the current data provide support for strategies that increase habitual physical activity levels in the general population.

Effect of play-based summer break exercise on cardiovascular function in adolescents

AIM

To compare the effects of 4 and 8 weeks of play-based, supervised exercise during summer break versus an unsupervised break on cardiovascular function in adolescent children.

METHODS

Twenty-two subjects were divided into a 4-week exercise group (age 10.1 ± 1.3 years), an 8-week exercise group (age 9.4 ± 1.7 years) or a control group (age 10.0 ± 1.3 years). The activity groups participated in a supervised summer camp for 6 h/day, 5 days/week including a discontinuous play-based physical activity program and a healthy lifestyle, while the control group were told to keep their regular summer break routines. Anthropometrics, pulse wave velocity, augmentation index, blood pressure and peak oxygen consumption were evaluated before and after the intervention.

RESULTS

Normalized augmentation index (75 beats/min) significantly decreased after 4 and 8 weeks in the active groups (p = 0.04) while pulse wave velocity showed no significant changes in all groups. Mean arterial pressure decreased (p = 0.003) and peak oxygen consumption increased (p = 0.001) significantly in the 8 week group.

CONCLUSION

These data suggest that 8 weeks of supervised play-based activity yield several cardio-beneficial results in adolescents, which may act as a clinical prophylaxis throughout their lifetime.

Central adiposity and protein intake are associated with arterial stiffness in overweight children

Being overweight is associated with vascular abnormalities, which are important in the development of atherosclerosis. However, little is known about dietary and lifestyle determinants of vascular function in overweight children. In adults, dietary protein and milk intake are associated with reduced blood pressure and reduced risk of metabolic syndrome. This study examined the associations between dietary protein, milk intake, physical activity, and adiposity on arterial stiffness in overweight children. In a cross-sectional study, overweight children with habitual milk intakes ≤ 250 mL/d were examined by DXA scans, pedometer counts, anthropometry, and metabolic variables. Dietary intake was registered for 4 d. The outcomes were arterial stiffness measured by pulse wave velocity (PWV) (n = 182) and augmentation index (Aix) (n = 183). The PWV (mean ± SD) was 4.78 ± 0.72 m/s and the Aix was -0.77 ± 9.44%. In multivariate models, the android fat:gynoid fat and android fat:body fat ratios were positively associated with PWV (β = 1.49 and β = 10.3, both P < 0.05) and Aix (β = 28.3, P < 0.01 and β = 153, P < 0.05), whereas the gynoid fat:body fat ratio was negatively associated with the Aix (β = -134; P < 0.001). Protein intake (percentage energy) was positively associated with PWV (β = 0.05; P < 0.01). Milk intake (L/d) tended to be negatively associated with PWV (β = -0.64; P = 0.05). Pedometer counts were negatively associated with the Aix; however, the association became nonsignificant after controlling for HOMA, which was positively associated with the Aix (β = 0.95; P < 0.01). In conclusion, central adiposity and protein intake are associated with increased arterial stiffness measured as PWV in overweight children independent of blood pressure and heart rate. The effect of protein intake may be caused by meat, because the milk intake was low.

Digital Dermatoglyphic Heritability Differences as Evidenced by a Female Twin Study

The genetic and environmental contributions to determine digital dermatoglyphic traits were investigated by using female dizygotic and monozygotic twin pairs to estimate heritability indexes (h2). The evaluated sample was composed by 20 monozygotic twin pairs and 13 dizygotic twin pairs. A significant heritability (h2 = 0.65 to 0.96) was observed for 12 dermatoglyphic characteristics (delta indexes and ridge counts for right hand, left hand and both hands, and ridge counts for most individual fingers). A negative correlation between the ridge counts and heritability indexes from individual fingers was found for the left hand, which appears to be associated to a higher arch pattern frequency in most left-hand fingers, since this frequency was negatively correlated with ridge counts and positively correlated with heritability indexes. Heritability indexes of right-hand fingers were positively correlated with loop pattern frequency and negatively correlated with whorl pattern frequency. The low heritability of ridge counts from left thumb, ring and little fingers (h2 = 0.11 to 0.32) indicates a higher chance that the chorion type had an influence in the intra-pair variance of monozygotic twins. Results confirmed the predominant genetic influence on the total ridge count. The heritability indexes varied in up to 8 times between different fingers and its association to ridge counts and pattern frequency was very variable between hands, evidencing that the use of dermatoglyphic traits from individual fingers as indicators of genetic influences to other human traits should consider this variability.

Increased arterial stiffness is found in adolescents with obesity or obesity-related type 2 diabetes mellitus

OBJECTIVE

Adults with obesity or obesity-related type 2 diabetes (T2DM) are at higher risk for cardiovascular disease possibly due to increased arterial stiffness. We sought to determine if arterial stiffness is increased in youth with obesity or T2DM as compared with lean controls.

METHODS

Youth age 10-24 years (N = 670, 62% non-Caucasian, 35% male) were examined. They were stratified by the 85th% of BMI as lean (L=241), obese (O=234) or obese with T2DM (T2DM=195). Questionnaire, anthropometric, BP, laboratory (fasting glucose, insulin, HbA1c, lipids, CRP), physical activity, and DXA were collected. Brachial artery distensibility (BrachD), pulse wave velocity (PWV) and augmentation index (AIx) were measured. Group differences were evaluated by ANOVA. General linear multivariate models were constructed to elucidate independent determinates of arterial stiffness.

RESULTS

CV risk profile deteriorated from L to O to T2DM group. There was a progressive increase in AIx and PWV-trunk with progressive decline in BrachD from L to O to T2DM individuals (all P < 0.05). Group (status as L, O or T2DM) was an independent predictor of arterial stiffness even after adjusting for CV risk factors.

CONCLUSION

Arterial stiffness is increased in young individuals with obesity and obesity-related T2DM even after correction for risk factors.

Macrovascular and microvascular dysfunction in the metabolic syndrome

The metabolic syndrome (MetS) is associated with increased risk of type-2 diabetes and cardiovascular disease (CVD). We hypothesized that both small and large arteries may be impaired in subjects with the MetS, even in the absence of known CVD or diabetes. We compared both skin capillary density (CD) and pulse-wave velocity (PWV) in 36 cases with the MetS with those from 108 age- and gender-matched controls from the SU.VIM.AX-2 cohort. Compared with controls, MetS subjects demonstrated increased PWV (12.2+/-2.8 vs. 10.7+/-1.9 m s(-1), P=0.005) and lower functional CD (83.1+/-15.7 vs. 89.4+/-14.2 capillaries per mm(2), P=0.03). Functional CD was inversely related to fasting glucose, triglycerides (TGs) and HOMA-IR (all P<0.05). On the other hand, no association was found between CD and BP or with PWV. In multivariate models, the odds ratios (95% confidence interval) for one standard deviation change, for having an impaired PWV (>or=12 m s(-1), n=44), were: 1.65 (1.11-2.45) for systolic BP and 1.93 (1.25-2.99) for TG only. For impaired CD (<or=80 capillaries per mm(2)), the odds ratios (95% confidence interval) were 1.45 (1.00-2.08) for TG and 1.65 (1.13-2.43) for fasting glucose, only. In conclusion, MetS subjects exhibited evidence of macro- and microcirculatory dysfunction, even in the absence of diabetes and CVD. The common mechanism linking MetS components to CVD risk through small- and large-artery dysfunctions may be mediated through metabolic factors related to insulin resistance, not to increased BP.

Sport therapy for hypertension: why, how, and how much?

Exercise may prevent or reduce the effects of metabolic and cardiovascular diseases, including arterial hypertension. Both acute and chronic exercise, alone or combined with lifestyle modifications, decrease blood pressure and avoid or reduce the need for pharmacologic therapy in patients with hypertension. The hypotensive effect of exercise is observed in a large percentage of subjects, with differences due to age, sex, race, health conditions, parental history, and genetic factors. Exercise regulates autonomic nervous system activity, increases shear stress, improves nitric oxide production in endothelial cells and its bioavailability for vascular smooth muscle, up-regulates antioxidant enzymes. Endurance training is primarily effective, and resistance training can be combined with it. Low-to-moderate intensity training in sedentary patients with hypertension is necessary, and tailored programs make exercise safe and effective also in special populations. Supervised or home-based exercise programs allow a nonpharmacological reduction of hypertension and reduce risk factors, with possible beneficial effects on cardiovascular morbidity.

HEREDITARY AND ENVIRONMENTAL INFLUENCES ON ARTERIAL FUNCTION

1. With the ageing population and increasing heart failure, arterial function has been shown to contribute to cardiovascular risk because of its adverse effects on ventriculovascular coupling. Population studies have confirmed independent prognostic information of arterial stiffening on cardiovascular survival. 2. The term 'arterial function' encompasses a range of phenotypes, including measures of arterial structure/remodelling, measures of arterial wall mechanics, surrogate measures of stiffness and of wave reflection. There exists significant interaction between these measures and none is truly independent of the others. Added to this complexity is the recognition that, although arterial function has a strong genetic component, quantification requires a range of techniques from twin to family and population studies. 3. The contribution of heritability is often derived from statistical models with input from genomic scanning and candidate gene studies. Studies to date confirm a significant heritable component for the majority of phenotypes examined. However, it has also been recognized that the factors involved in blood pressure maintenance are likely to be separate to those in arterial structural degeneration with ageing. Candidate genes for arterial function go beyond those of the sympathetic and renin-angiotensin systems and include genes involved in signalling pathways and extracellular matrix modulation. 4. The present review examines the evidence for heritability of the major arterial function phenotypes with environmental and ageing modulation. A brief overview of the impact of atherosclerotic risk factors on arterial function is included.

Increased arterial stiffness in remote Indigenous Australians with high risk of cardiovascular disease

OBJECTIVE

To assess central and peripheral arterial stiffness in Indigenous and European Australians with and without type 2 diabetes using applanation tonometry to obtain the augmentation index (AI) and pulse wave velocity (PWV).

METHODS

AI was assessed in 162 Indigenous Australians (60 with type 2 diabetes) participating in a population-based study and 121 Australians of European ancestry (38 with diabetes) of similar age and sex. PWV was assessed in a subgroup: n = 62 indigenous, n = 118 European participants.

RESULTS

The indigenous group had higher AI than the European group [mean (SD) 32 (12) versus 24 (12)%, P < 0.0001] and carotid-femoral PWV [8.4 (1.8) versus 7.1 (2.2) ms(-1), P < 0.0001]. There were no significant differences between groups regarding blood pressure and total cholesterol; however, indigenous individuals had higher fasting glucose, insulin, haemoglobin A1c, triglycerides, waist circumference (despite lower body mass index), and a higher prevalence of cigarette smoking. Fifty-five per cent of the variance in AI was explained on multiple regression analysis by age, sex, indigenous participant, heart rate, mean arterial pressure, height, triglycerides and waist circumference. Age, indigenous participant, heart rate, mean arterial pressure and antihypertensive medication explained 56% of the variance in PWV. Variables of the metabolic syndrome and smoking, C-reactive protein (CRP), homocysteine and heart rate clustered with indigenous status on factor analysis.

CONCLUSIONS

Indigenous Australians have higher indices of peripheral and central arterial stiffness than European Australians of similar age and sex. Factor analysis revealed that metabolic syndrome variables, smoking, CRP, homocysteine and heart rate clustered with 'indigenous participant' and may explain increased arterial stiffness in this group.

Effect of postprandial insulinemia and insulin resistance on measurement of arterial stiffness (augmentation index)

BACKGROUND

Arterial stiffness, specifically augmentation index (AIx), is an independent predictor of cardiovascular risk. Previous studies suggest that insulin infusion decreases AIx and that this response is attenuated in insulin resistance. Whether physiological postprandial insulinemia similarly affects AIx measurements, and whether insulin resistance modifies this response, has not been studied.

METHODS

Seven relatively insulin-resistant and seven insulin-sensitive postmenopausal women received low-carbohydrate and high-carbohydrate high-fat meals on separate days. Glucose and insulin levels were measured for 360-min following meal consumption. AIx was measured by radial artery applanation tonometry at regular intervals postprandially.

RESULTS

Postprandial increases in glucose and insulin were greater following the high-carbohydrate high-fat meal in both insulin-sensitive and insulin-resistant subjects. AIx decreased in both groups following both meals. In insulin-sensitive subjects, the postprandial reduction (incremental area above the curve) in AIx was greater following the high-carbohydrate vs. low-carbohydrate high-fat meal (-6821+/-1089 vs. -3797+/-1171% x min, respectively, P=0.009). In contrast, in insulin-resistant subjects, postprandial AIx responses were similar following the meals, suggesting that insulin resistance is associated with impaired postprandial arterial relaxation.

CONCLUSIONS

This study demonstrates that the carbohydrate content of a meal, and, hence, the magnitude of the postprandial glucose and insulin responses it elicits, are important determinants of postprandial AIx measurements. The further observation that insulin resistance modified this effect raises the possibility that this phenomenon is a contributor to increased cardiovascular risk in insulin resistance. The results indicate that future studies of AIx need to control for the effects of these potentially confounding variables and that measurement of AIx should be standardized with respect to meals.

Impaired arterial elasticity in young patients with white-coat hypertension

BACKGROUND

Conflict still exists over whether patients with white-coat hypertension are at increased risk of developing target organ damage compared with normotensive individuals.

METHODS

We studied vascular distensibility in 117 young-to-middle age patients with white-coat hypertension, 174 patients with sustained hypertension, and 51 normotensive controls. To obtain a measure of compliance, a model was used that divides the total systemic compliance into large artery (C1) and small artery (C2) compliance. With this aim, radial arterial pulse waves were recorded with a tonometer sensor array by means of an HDI CR2000 device (Eagan, Minnesota, USA). Moreover, pulse wave velocity and the augmentation index were measured using the Specaway DAT system (St Pauls, Sydney, Australia).

RESULTS

Patients with sustained hypertension had a greater body mass index than patients with white-coat hypertension (P=0.04) or the normotensive individuals (P=0.01). C1 and C2 were decreased in the two hypertensive groups as compared with those in the normotensive group (P=0.0002 and 0.03, respectively, versus sustained hypertension; P=0.00007 and 0.0004, respectively, versus white-coat hypertension). Pulse wave velocity and aortic augmentation index were increased in the white-coat hypertension patients compared with the normotensive individuals (P=0.02 and 0.004, respectively). Aortic augmentation index (P=0.008) but not pulse wave velocity was increased in the sustained hypertensive patients compared with that in the normotensive individuals. All indexes of arterial distensibility were similar in the two hypertensive groups.

CONCLUSIONS

Indexes of arterial distensibility are impaired in the white-coat hypertensive group and similar to those in the sustained hypertensive group, indicating that early changes in the arterial wall can occur in white-coat hypertension. This may account for the higher risk of stroke that has been described in this condition.

Central obesity is associated with reduced peripheral wave reflection in Indigenous Australians irrespective of diabetes status

OBJECTIVE

To determine the influence of central obesity and type 2 diabetes on peripheral wave reflection in Indigenous Australians.

DESIGN AND METHODS

A cross-sectional study of remote Indigenous Australians with (n = 43) and without (n = 54) type 2 diabetes of similar age (47 years) and sex; using anthropometric and bioelectrical impedance measures of obesity and applanation tonometry to determine the aortic augmentation index (AI) as an index of peripheral wave reflection.

RESULTS

Indices of obesity were significantly higher in the diabetic than non-diabetic participants [body mass index (BMI): 27.3 versus 24.6 kg/m, P = 0.018; waist circumference: women 101 versus 94 cm, P = 0.008, men 102 versus 91 cm, P = 0.039]. AI was negatively related to obesity: BMI (r = -0.35, P = 0.0003), weight (r = -0.44, P < 0.0005), waist circumference (r = -0.34, P = 0.0003) and fat mass (r = -0.35, P < 0.0005). There was no significant difference in AI between the groups with and without diabetes. On multiple regression analysis, 66% of the variance in AI was explained with the following significant predictors: age, heart rate, male gender, fat mass and mean arterial pressure. Similar results were obtained when weight, waist circumference or BMI were substituted for fat mass.

CONCLUSION

When compared with Indigenous Australians without diabetes, those with type 2 diabetes do not have greater aortic pressure augmentation from peripheral wave reflection. However, obesity, irrespective of the index used, was related to lower peripheral wave reflection in both those with and without type 2 diabetes.

Alcohol and arterial wave reflections in middle aged and elderly men

BACKGROUND

Augmentation index (AIx) is a measure of arterial wave reflection, providing information on the workload of the heart. and is a possible marker for cardiovascular disease risk. The relation of alcohol consumption with cardiovascular disease (CVD) risk is U-shaped with a protective effect of moderate alcohol consumption. The relation of alcohol consumption level with AIx has not been widely investigated, which prompted this study of the relation of alcohol consumption with AIx in a population-based cohort of men aged 40-80 years.

METHODS

Three hundred and seventy-four men (mean age 60.5 years) participated in this cross-sectional study. Alcohol consumption and smoking habits were determined through a validated questionnaire. Fasting blood samples were drawn and analyzed for glucose and lipid levels and AIx was estimated by radial applanation tonometry using the SphygmoCor Device. The resultant data were analyzed using linear regression models.

RESULTS

Age, height, heart rate, blood pressure, packyears, current smoking, presence of CVD and hypertension were independently related to AIx. The relation of alcohol consumption with AIx was U-shaped, with a significantly lower AIx in the group drinking 4-8 glasses/week (difference = -2.91%, 95% CI [-5.65; -0.18]) relative to those drinking 0-3 glasses/week. Additional adjustment for current smoking did not change this relationship, but adjustment for pulse wave velocity attenuated the relation.

CONCLUSIONS

In a population-based cohort of men aged 40-80 years the relation of alcohol consumption level with AIx was U-shaped, further expanding the evidence for vascular protective effects of moderate alcohol intake.

Beneficial postprandial effect of a small amount of alcohol on diabetes and cardiovascular risk factors: modification by insulin resistance

Moderate alcohol consumption protects against type 2 diabetes and cardiovascular disease. Because humans spend most of their time in the postprandial state, we examined the effect of 15 g alcohol on postprandial metabolic factors in 20 postmenopausal women over 6 h. We measured 1) glucose, insulin, lipids, C-reactive protein, and adiponectin levels; 2) augmentation index by applanation tonometry; and 3) energy expenditure and substrate oxidation by indirect calorimetry. Subjects received low carbohydrate (LC; visits 1 and 2) and high carbohydrate (HC; visits 3 and 4) high fat meals with and without alcohol. Alcohol augmented the postprandial increment in insulin (P = 0.07) and reduced the postprandial increment in glucose (P = 0.04) after the LC meal only. Triglycerides were increased by alcohol after the LC (P = 0.002) and HC (P = 0.008) meals. Total and high-density lipoprotein cholesterol, fatty acids, and total adiponectin responses were unaffected. C-reactive protein levels decreased postprandially; reductions were enhanced by alcohol after the HC meal, but were attenuated after the LC meal. Postprandial reductions in the augmentation index were increased by alcohol after the LC meal only (P = 0.007). Alcohol enhanced the postprandial increase in energy expenditure 30-60 min after the LC meal (increase, 373 +/- 49 vs. 236 +/- 32 kcal/d; P = 0.02) and HC meal (increase, 362 +/- 36 vs. 205 +/- 34 kcal/d; P = 0.0009), but suppressed fat and carbohydrate oxidation. Some of our findings may be mechanisms for lower diabetes and cardiovascular risks in moderate drinkers.

Increased pulse wave velocity is not associated with elevated augmentation index in patients with diabetes

OBJECTIVE

Increased arterial stiffness is a risk factor for cardiovascular disease and is a feature associated with diabetes. Pulse wave velocity (PWV) is an accepted index of arterial stiffness and augmentation index (AI) derived from radial applanation tonometry has been advocated as a measurement of arterial stiffness. This study compares the relationship between PWV and AI in people with and without diabetes.

DESIGN AND METHODS

A total of 66 people with diabetes and 66 age-matched non-diabetic controls were studied. Central aortic pressure waves were generated using applanation tonometry over the radial artery and used to calculate AI. Carotid-femoral PWV (PWVcf) was measured simultaneously.

RESULTS

Relative to controls, diabetes was associated with increased pulse pressure (PP) and PWVcf (P < 0.01). In contrast, AI did not differ between groups even after adjustment for heart rate. This observation remained consistent irrespective of diabetes type, arterial site, and the presence or absence of antihypertensive therapy. Multiple regression analysis revealed diabetes to be a significant determinant of PWVcf, but not AI.

CONCLUSIONS

PP and PWVcf are increased in people with diabetes, but this is not associated with increased AI. These findings conclusively demonstrate that AI is not a reliable measure of arterial stiffness in people with diabetes.

Arterial stiffness and the systolic hypertension syndrome

PURPOSE OF REVIEW

This review is intended to provide the background for a new comprehensive hemodynamic view of the syndrome of systolic or wide pulse pressure hypertension and its hallmark abnormality: increased central arterial stiffness.

RECENT FINDINGS

Studies of the pathogenesis of systolic hypertension have lagged. This review describes the systolic hypertension syndrome as a complex set of hemodynamic maladaptations that include stiff central arteries, normal peripheral arteries with variable pressure amplification characteristics, arteriolar constriction, microcirculatory rarefaction, metabolic abnormalities, cardiac hypertrophy, and increased blood pressure variability. Because the structural and functional properties of arteries of different caliber are highly heterogeneous and vary with aging and disease, simple measurements such as standard brachial artery blood pressure, brachial pulse pressure, or mean arterial pressure are inadequate to provide meaningful insight into the pathophysiology of the syndrome. Additional parameters developed to describe changes in arterial mechanics (arterial compliance or stiffness, elastic modulus, impedance, pulse wave velocity, augmentation index, and pulse pressure amplification) are intrinsically limited and are directly or indirectly pressure-dependent. Quantitation of central arterial stiffness provides a modest increment in cardiovascular and renal risk stratification.

SUMMARY

Better clinical management of systolic hypertension depends on greater insight into the syndrome as a whole, more critical analysis of existing techniques, and the development of new approaches.