The metabolic syndrome and related cardiovascular risk

l-Theanine attenuates neointimal hyperplasia via suppression of vascular smooth muscle cell phenotypic modulation

Neointimal hyperplasia is a prominent pathological phenomenon in the process of stent restenosis. Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) play major pathological processes involved in the development of restenosis. l-Theanine, one of the major amino acid components in green tea, has been reported to improve vascular function. Here we display the effects of l-theanine on neointima formation and the underlying mechanism. In the rat carotid-artery balloon-injury model, l-theanine greatly inhibited neointima formation and prevented VSMCs from a contractile phenotype switching to a synthetic phenotype. In vitro study showed that l-theanine significantly inhibited PDGF-BB-induced VSMC proliferation and migration, which was comparable with the effect of l-theanine on AngII-induced VSMC proliferation and migration. Western blot analysis demonstrated that l-theanine suppressed PDGF-BB and AngII-induced reduction of SMA and SM22α and increment of OPN, suggesting that l-theanine inhibited the transformation of VSMCs from contractile to the synthetic phenotype. Further experiments showed that l-theanine exhibits potential preventive effects on neointimal hyperplasia and related vascular remodeling via inhibition of phosphorylation of Elk-1 and activation of MAPK1. The present study provides the new experimental evidence that l-theanine has potential clinical application as an anti-restenosis agent for the prevention of restenosis.

[CASERIA program (Healthy Habits in Primary School Questionnaire). Responses of 6 to 10 year-old children]

In schoolchildren examinations, carried out periodically, we detect a continuous increase in obesity and sedentarism in our schoolchildren. In this study we attempt to compare, with objective data, the real situation of the childhood population in our area, as regards their eating habits, physical activity and hygiene.

MATERIAL AND METHODS

Questionnaires on eating habits, preferences as regards diet, doing exercise, and dental hygiene, were handed out to 430 schoolchildren between 6 and 10 years-old. A total of 366 were valid for the study.

RESULTS

The majority (85.8%) of those surveyed lived within a "traditional" family; 22% had family members who were overweight; 96.7% had breakfast before going to school, with milk products being the most consumed; the cake and pastry industry was well used, both at breakfast (7.4%) and at playtime (16.9%). The favourite food was pasta in 29.8% of cases, followed by potatoes, particularly fried (10.4%). The least liked foods were vegetables (26.2%) and fish (8.2%). Television was watched for more than 2 hours by 70%; 34% exceeded 2 hours or more per day playing with video consoles or similar. On the other hand, homework and studying took up more than 2 hours daily for 50% of pupils. A majority (55%) of those surveyed ate sweets 2 or more time a day, and to eat and watch television at the same time was an almost constant habit in more than 60%. Of the participants in the study, 9.29% never brushed their teeth.

CONCLUSIONS

The theoretical knowledge of what should be a correct diet seems adequate, but its putting into practice is not. The population studies had fairly sedentary habits, with little fruit and they did not like pulses or vegetables or fish. All these factors decrease the cardiovascular protection associated with its practice and consumption. We have shown that they are already present since childhood in our population, which without a doubt will have repercussions in their future health status and well-being, if it is not changed.

Menopause, the metabolic syndrome, and mind-body therapies

Cardiovascular disease risk rises sharply with menopause, likely due to the coincident increase in insulin resistance and related atherogenic changes that together comprise the metabolic or insulin resistance syndrome, a cluster of metabolic and hemodynamic abnormalities strongly implicated in the pathogenesis and progression of cardiovascular disease. A growing body of research suggests that traditional mind-body practices such as yoga, tai chi, and qigong may offer safe and cost-effective strategies for reducing insulin resistance syndrome-related risk factors for cardiovascular disease in older populations, including postmenopausal women. Current evidence suggests that these practices may reduce insulin resistance and related physiological risk factors for cardiovascular disease; improve mood, well-being, and sleep; decrease sympathetic activation; and enhance cardiovagal function. However, additional rigorous studies are needed to confirm existing findings and to examine long-term effects on cardiovascular health.

A review of the economic evidence for acarbose in the prevention of diabetes and cardiovascular events in individuals with impaired glucose tolerance

The highly prevalent, prediabetic condition of impaired glucose tolerance (IGT) confers a high risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). There is an emerging body of cost-effectiveness literature in the management of IGT. For acarbose, an alpha-glucosidase inhibitor, economic analyses have been conducted for Spain, Germany, Sweden and Canada. In Spain, acarbose was more effective and less costly (dominant) compared with placebo. In Germany, the cost per patient free of diabetes was under Pounds 800; acarbose was dominant for those at high risk for T2DM, CVD or both, and a similar outcome in the Swedish study. In Canada, acarbose was dominant compared with no intervention and very cost-effective compared with metformin [C Dollars 1798/life years gained (LYG)]. The particularly cost-effective outcomes or cost savings delivered by acarbose for IGT subjects at high risk for T2DM and/or CVD render an IGT-intervention program prioritised to such high-risk individuals an economically attractive strategy.

Ambulatory blood pressure reduction after rosiglitazone treatment in patients with type 2 diabetes and hypertension correlates with insulin sensitivity increase

BACKGROUND

Within the metabolic syndrome, insulin resistance and compensatory hyperinsulinemia are associated with blood pressure (BP) elevation through various potential mechanisms. Thiazolidinediones are antihyperglycemic agents that decrease insulin resistance.

OBJECTIVE

To determine the effect of the thiazolidinedione rosiglitazone on BP and insulin resistance in patients with type 2 diabetes and hypertension.

METHODS

In 20 subjects (nine men and 11 women) with type 2 diabetes but with a poor glycemic control, and with poorly controlled or newly diagnosed hypertension, rosiglitazone 4 mg daily was added-on therapy for 26 weeks. At baseline and at the end of the treatment period patients underwent ambulatory blood pressure monitoring, a hyperinsulinemic euglycemic clamp, and blood tests for glucose, insulin, HbA1c, lipids, and routine laboratory parameters.

RESULTS

Insulin sensitivity estimated with the clamp significantly increased (Mbw/I index changed from 33.9 +/- 2.6 to 41.9 +/- 3.2 micromol/min per kg per nmol/l, P < 0.001) and the HOMA-IR index significantly decreased (6.34 +/- 0.39 versus 4.40 +/- 0.33, P < 0.001) during rosiglitazone treatment. Ambulatory BP presented small but significant reductions for the total 24-h period (135.3 +/- 1.8 versus 129.9 +/- 1.7 mmHg, P < 0.001 for systolic BP and 76.0 +/- 1.6 versus 71.9 +/- 1.6 mmHg, P < 0.001 for diastolic BP), daytime and night-time. The changes in systolic and diastolic BP correlated with the change in insulin sensitivity (r = -0.78, P < 0.01 and r = -0.68, P < 0.01, respectively). There were also significant reductions in fasting plasma glucose (9.39 +/- 0.41 versus 7.55 +/- 0.31 mmol/l, P < 0.001), insulin (94.0 +/- 0.41 versus 79.5 +/- 5.6 pmol/l, P < 0.01) and HbA1c (8.15 +/- 0.24 versus 7.24 +/- 0.19%, P < 0.001).

CONCLUSIONS

Treatment of type 2 diabetic hypertensive patients with rosiglitazone significantly increased insulin sensitivity and lowered ambulatory BP. These changes were strongly correlated. Thiazolidinediones may thus possess a BP-lowering effect beyond their antihyperglycemic properties.

Arterial hypertension and ischaemic stroke

OBJECTIVES

Arterial hypertension is, besides age, the number one risk factor for ischaemic stroke. Patients with arterial hypertension frequently present with additional coexisting vascular risk factors interacting in a complex way.

MATERIAL AND METHODS

This paper reviews the benefit of antihypertensive treatment, as well as different treatment options of arterial hypertension and their side-effects.

RESULTS

Patients with definite arterial hypertension, but also patients with so-called normal or high-normal blood pressure are at increased risk to develop stroke and other cardiovascular complications. Vascular remodelling of small and large vessels provoked by arterial hypertension is the initial step in the development of atherosclerosis and lipohyalinosis. Vascular remodelling can be improved or even normalized by antihypertensive treatment with angiotensin-converting-enzyme inhibitors and angiotensin-I-receptor antagonists showing the most convincing effects. Angiotensin-converting-enzyme inhibitors and angiotensin-I-receptor antagonists have the lowest rate of side-effects, however, economic restraints hinder their general application. Statins are needed to treat dyslipidaemia. They also lower blood pressure and have a synergistic effect with the above two antihypertensive components in lowering blood pressure. In hypertensive patients, risk of stroke and other cardiovascular complications is determined by the blood pressure level and the presence or absence of target organ damage and the interaction with other risk factors, such as cigarette smoking, dyslipidaemia, and diabetes. These high-risk patients should be treated even more aggressively than usual.

CONCLUSIONS

In the vast majority of patients and healthy individuals, target blood pressure should be as high as or below 120/80 mmHg to minimize the occurrence of stroke and other cardiovascular complications.

Factors associated with improved short term survival in obese end stage renal disease patients

PURPOSE

In contrast to its role in the general population, obesity, defined as body mass index (BMI) > or = 30 kg/m(2), has been associated with improved survival in patients with end stage renal disease (ESRD). This apparent benefit has not been explained.

METHODS

Using the United States Renal Data System (USRDS), we performed an historical cohort study on 151,027 patients initiated on ESRD therapy between January 1, 1995 and June 30, 1997, who never received renal transplants, and who had information sufficient to calculate BMI. We explored the association of various comorbidities present at the time of dialysis initiation (from HCFA Form 2728) with the presence of obesity by logistic regression, and the association of obesity with patient survival, including specific causes of death, by Cox regression adjusting for factors known to be associated with survival in this population.

RESULTS

Obese patients had an unadjusted two-year survival of 68% compared with 58% for non obese patients. Obesity was independently associated with a reduced risk of mortality among chronic dialysis patients (adjusted hazard ratio (AHR) 0.75, 95% confidence interval, 0.72-0.78), after controlling for all comorbidities and risk factors. However, there were significantly adverse interactions among whites (AHR 1.22, 1.14-1.30, across all causes of death) and females (AHR 1.12, 1.04-1.20, entirely due to an increased risk of infectious death).

CONCLUSIONS

Obesity in patients presenting with ESRD is associated independently with reduced all cause mortality; however, the relationship is complex and is stronger in African Americans. In addition, subgroup analysis suggests that obesity is associated with increased risk of infectious death in females.

Impact of renal transplantation on survival in end-stage renal disease patients with elevated body mass index

BACKGROUND

Cadaveric renal transplantation is associated with a survival advantage compared with dialysis patients remaining on the renal transplantation waiting list, but this advantage has not been confirmed in obese end-stage renal disease (ESRD) patients.

METHODS

Using data from the USRDS, we studied 7521 patients who presented with ESRD from 1 April 1995 to 29 June 1999 and later enrolled on the renal transplantation waiting list with body mass indices (BMI) >or=30 kg/m(2) at the time of presentation to ESRD, and followed until 6 November 2000. Recipients of preemptive renal transplantation or organs other than kidneys were excluded. Cox non-proportional hazards regression models were used to calculate adjusted, time-dependent hazard ratios (HR) for time to death in a given patient during the study period, controlling for renal transplantation, demographics and comorbidities (Form 2728).

RESULTS

The incidence of mortality was 3.3 episodes per 100 patient-years (PY) in cadaveric renal transplantation and 1.9/100 PY in living donor renal transplantation compared with 6.6 episodes/100 PY in all patients on the transplant waiting list. In comparison to maintenance dialysis, both recipients of solitary cadaveric kidneys (HR 0.39, 95% CI 0.33 to 0.47), and recipients of living donor kidneys (HR 0.23, 95% CI 0.16 to 0.34) had statistically significant improved survival. A benefit of cadaveric renal transplantation did not apply to patients with BMI >or=41 kg/m(2) (HR 0.47, 95% CI, 0.17 to 1.25, P = 0.13).

CONCLUSIONS

Obese patients on the renal transplant waiting list had a significantly lower risk of mortality after renal transplantation compared with those remaining on dialysis.

Discrimination of health risk by combined body mass index and waist circumference

OBJECTIVE

NIH Clinical Guidelines (1998) recommend the measurement of waist circumference (WC, centimeters) within body mass index (BMI, kilograms per square meter) categories as a screening tool for increased health risk.

RESEARCH METHODS AND PROCEDURES

The Canada Heart Health Surveys (1986 through 1992) were used to describe the prevalence of the metabolic syndrome in Canada and to test the use of the NIH guidelines for predicting metabolic risk factors. The sample included 7981 participants ages 20 to 74 years who had complete data for WC, BMI, high-density lipoprotein-cholesterol, triglycerides, diabetic status, and systolic and diastolic blood pressures. National Cholesterol Education Program Adult Treatment Panel III risk categories were used to identify the metabolic syndrome and associated risk factors. Logistic regression was used to test the hypothesis that WC improves the prediction of the metabolic syndrome, within overweight (25 to 29.9 kg/m(2)) and obese I (30 to 34.9 kg/m(2)) BMI categories.

RESULTS

The prevalence of the metabolic syndrome was 17.0% in men and 13.2% in women. The odds ratios (OR) for the prediction of the metabolic syndrome were elevated in overweight [OR, 1.85; 95% confidence interval (95%CI), 1.02 to 3.35] and obese (OR, 2.35; 95%CI, 1.25 to 4.42) women with a high WC compared with overweight and obese women with a low WC, respectively. On the other hand, WC was not predictive of the metabolic syndrome or component risk factors in men, within BMI categories.

DISCUSSION

In women already at increased health risk because of an elevated BMI, the additional measurement of WC may help identify cardiovascular risk.

Metabolic syndrome and aging in Wistar Ottawa Karlsburg W rats

BACKGROUND AND OBJECTIVE

Comparative studies have shown that Wistar Ottawa Karlsburg W (RT1u) rats (WOKW) develop a nearly complete metabolic syndrome with obesity, moderate hypertension, dyslipidemia, hyperinsulinemia, and impaired glucose tolerance up to an age of 28 weeks. Because metabolic data thereafter are missing, WOKW and disease-resistant DA rats were studied for 12 months beginning at an age of 5 months.

METHODS

Eighteen male inbred WOKW and DA rats were studied monthly from the 5th to the 17th month of life for traits of the metabolic syndrome such as body weight, body mass index (BMI), serum triglycerides, total cholesterol, leptin, insulin as well as glucose tolerance, 24 h excretion of urine total protein and creatinine including telemetric measurement of blood pressure in six males per each group.

RESULTS

Except for serum total cholesterol, the measured values for most traits studied were significantly higher in WOKW than in DA rats at an age of 5 months. At an age of 17 months all traits were significantly elevated in WOKW compared with DA rats. WOKW rats were hypertensive, dyslipidemic, obese, glucose intolerant, hyperinsulinemic and proteinuric.

CONCLUSION

Considering the phenotype of the WOKW rat described until now and the fact that the metabolic syndrome in this rat is polygenetically determined, the WOKW rat is the most suitable animal model to study the pathophysiology of the facets of the syndrome.

Vascular signaling pathways in the metabolic syndrome

There are several potential cellular and molecular pathways whereby cardiovascular risk factors act through very specific signal transduction pathways in the formation of atherosclerosis, as seen often in the metabolic syndrome. Many examples point to multiple postreceptor defects in the insulin signaling pathway in vascular tissue, however, there are differences in the insulin receptor pathway in vascular tissue compared with skeletal muscle or fat. In addition to insulin receptors, insulin may affect atherosclerotic changes in the vascular cells via stimulation of insulin-like growth factor-1 receptors and their signaling pathway. Insulin also causes activation of the vascular renin-angiotensin system in both vascular smooth muscle cells and endothelial cells. Insulin-activated tissue renin-angiotensin system leads to increased cell growth and contributes to the cause of atherosclerosis. The fact that agents that inhibit the renin-angiotensin system also block insulin-mediated renin-angiotensin system expression and cell growth reinforces the potential implication of a vascular insulin-renin-angiotensin system pathway. Finally, novel substances such as the adipokines, factors produced from fat cells, reveal new risk factors in the metabolic syndrome and offer further evidence for a link between insulin resistance and accelerated atherosclerosis.

Pathophysiology of hypertension and endothelial dysfunction in patients with diabetes mellitus

There is compelling evidence for endothelial dysfunction in both type 1 and type 2 diabetics. This dysfunction is manifest as blunting of the biologic effect of a potent endothelium-derived vasodilator, nitric oxide, and increased production of vasoconstrictors such as angiotensin II, ET-1, and cyclooxygenase and lipoxygenase products of arachidonic acid metabolism. These agents and other cytokines and growth factors whose production they stimulate cause acute increases in vascular tone, resulting in increases in blood pressure, and vascular and cardiac remodeling that contributes to the microvascular, macrovascular, and renal complications in diabetes. Reactive oxygen species, overproduced in diabetics, serve as signaling molecules that mediate many of the cellular biochemical reactions that result in these deleterious effects. Adverse vascular consequences associated with endothelial dysfunction in diabetes mellitus are Decreased nitric oxide formation, release, and action Increased formation of reactive oxygen species Decreased prostacyclin formation and release Increased formation of vasoconstrictor prostanoid Increased formation and release of ET-1 Increased lipid oxidation Increased cytokine and growth factor production Increased adhesion molecule expression Hypertension Changes in heart and vessel wall structure Acceleration of the atherosclerotic process Treatment with antioxidants and with inhibitors of the renin-angiotensin system may reverse some of the pathologic vascular changes associated with endothelial dysfunction.

Connections between obesity and dyslipidaemia

The importance of the obesity-lipid connection has suffered from the traditional reductionism view of science. Excess body weight has rarely been deemed an independent risk factor for coronary heart disease, directing physicians to target therapies towards the risk factors that excess body weight modifies (e.g. raising HDL, lowering blood pressure) instead of targeting the cause. The efforts of Adult Treatment Panel III to define and identify the metabolic syndrome as a secondary target may spur practitioners to revisit the need for weight management in patients with lipid disorders.