Insulin resistance and systemic hypertension

High blood pressure mediated the effect of fasting insulin level on nonalcoholic fatty liver disease risk: A Mendelian randomization study

Objective

The interactions between fasting insulin levels, high blood pressure and nonalcoholic fatty liver disease (NAFLD) are still unclear. We examined the causal mechanisms between these three cardiometabolic traits using Mendelian randomization (MR) approach by utilizing genetic instruments.

Methods

Three different genome-wide association studies resources of European ancestry were utilized for the present study. Two-sample MRs were used to assess causal effects between fasting insulin levels, high blood pressure and NAFLD. Multivariate MR was used to calculate the mediating effect. The inverse variance-weighted method was used as the main analysis method.

Results

Our study confirmed a causal effect of fasting insulin levels (IVW-OR = 9.54, P = 0.001) and high blood pressure (IVW-OR = 3.926, P = 0.005) on NAFLD risk. And fasting insulin level was positively casually associated with high blood pressure risk (IVW-OR = 1.170, P < 0.001). However, the impact of high blood pressure on fasting insulin levels was still uncertain because of the presence of horizontal pleiotropy. Reverse MR showed NAFLD had a positive correlation with fasting insulin levels (IVW-OR = 1.010, P < 0.001) and a negative causal effect on high blood pressure risk (IVW-OR = 0.997, P = 0.037). Combined the multivariate MR result revealed high blood pressure partially mediated the contribution of fasting insulin level to NAFLD risk (proportion mediated: 9.091%).

Conclusions

Our study suggests there is a bidirectional causal relationship between fasting insulin levels and NAFLD. High blood pressure seems to play a mediating role in the development of NAFLD caused by changes in fasting insulin levels. However, it is uncertain whether high blood pressure is a mediator between NAFLD and the risk of fasting insulin level.

The effect of bezafibrate in preventing glucolipid abnormalities induced by the antipsychotic risperidone

The present study aimed to investigate the effect of bezafibrate on glucolipid abnormalities induced by antipsychotics in schizophrenia. Patients in the treatment group (group A) were treated with antipsychotics and a daily dose of 200 mg bezafibrate for 12 weeks, and patients in the control group (group B) were treated with antipsychotics; sugar, fat and weight changes before and after the treatment were compared between the two groups. Before treatment the differences in TG, TC, LDL-C, HDL-C, body weight and blood glucose between groups A and B were not statistically significant. However, in group B, levels of TG, TC, LDL-C, body weight and blood glucose after treatment showed statistically significant increases, although levels of HDL-C did not register any statistically significant change. By contract, in group A, there were no statistically significant changes in any of the variables measured. Bezafibrate can prevent an increase in sugar, fat and weight gain in treating schizophrenia patients with antipsychotics, and low doses of bezafibrate are safe in the antipsychotic treatment for schizophrenia.

Adipocytokines and High Blood Pressure in Mexican Children

Given that adipocytokines may play an important role in the pathophysiology of high blood pressure (HBP) and because related reports in children are scarce and controversial, we evaluated the relationship of leptin, resistin, tumor necrosis factor-α, interleukin-6, adiponectin, and interferon-γ with HBP. Materials and Methods. A total of 129 (53.8%) girls and 111 (46.2%) boys, with average ages of 10.8 ± 0.9 and 10.6 ± 1.0 years, respectively, were enrolled in a cross-sectional study. HBP was defined by systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) between the 90th and 95th percentiles. A multivariate logistic regression backwards-stepwise analysis adjusted for body mass index, waist circumference, and triglyceride levels was performed to compute the association between adipocytokines and HBP. Results. Seventy-two (30.0%) participants showed HBP: 44 (61.1%) girls and 28 (38.9%) boys. Multivariate analysis showed that, irrespective of obesity, serum levels of adiponectin, but not those of other adipocytokines, are inversely associated with HBP (odds ratio 0.93; 95% CI 0.77 to 0.98, p = .04). Conclusions. Our results show that low serum adiponectin levels, but not those of other adipocytokines, are inversely associated with HBP; this association is independent of obesity.

Atherosclerosis in Type 2 Diabetes Mellitus: The Role of Insulin Resistance

Type 2 diabetes mellitus is associated with a marked increase in the risk of atherosclerotic diseases, including coronary heart disease, peripheral arterial disease, and cerebrovascular disease. Insulin resistance is a key factor in the pathogenesis of type 2 diabetes mellitus. Insulin resistance and its attendant metabolic abnormalities may cause much of the increased cardiovascular risk of type 2 diabetes mellitus. Among the abnormalities associated with insulin resistance are dyslipidemia, hypertension, systemic inflammation, and a prothrombotic state. This review discusses the role that each of these disorders plays in the cardiovascular risk of type 2 diabetes mellitus.

Insulin resistance in Nigerians with essential hypertension

BACKGROUND

Reports on the association between hypertension and insulin resistance have been inconsistent even though most studies show a definite association. It is also not certain if the association between insulin resistance and hypertension applies to all populations.

OBJECTIVE

To determine the prevalence of insulin resistance in hypertensive Nigerians and to examine the association of insulin resistance with hypertension and some anthropometric indices.

METHODS

Thirty five adults with essential hypertension and thirty five normotensives were studied. Anthropometric parameters, blood pressure, fasting glucose and insulin were measured. Homeostasis model assessment (HOMA) was used to determine insulin resistance (IR).

RESULTS

The hypertensive subjects had significantly higher fasting insulin and HOMA-IR compared with normotensives (p = 0.02 and 0.04) respectively. There were significant correlations between HOMA-IR, BMI, waist and hip circumference in subjects with hypertension. At multiple linear regression, hypertension and body mass index were found to be the only significant predictors of insulin resistance.

CONCLUSION

The hypertensives we studied had a higher occurrence of insulin resistance compared to the normotensives. This makes it necessary for persons with hypertensive to have regular screening for diabetes and other categories of glucose intolerance as the increased insulin increases their risk of developing type 2 diabetes mellitus.

Impact of hyperinsulinemia on the development of hypertension in normotensive, nondiabetic adults: a 4-year follow-up study

BACKGROUND AND AIMS

This study aimed to investigate the association between baseline fasting insulin levels, changes in fasting insulin levels, and future development of hypertension in normotensive, non-diabetic, healthy adults.

METHODS

We analyzed data from 11,123 adults, aged 20-65years, who had no history of hypertension or diabetes mellitus at a 2004 medical examination in a health promotion program and had attended a repeat examination in 2008. Subjects were divided into four groups according to baseline quartiles of fasting insulin and dichotomized fasting insulin levels at baseline and after 4years: low-low, low-high, high-low, high-high. We also assessed whether the association differed between the younger (20-40years) and older subjects (41-65years).

RESULTS

In four years, 1142 subjects (10.3%) developed hypertension. The odds ratio (OR) for the development for hypertension increased as the quartiles of baseline fasting insulin levels and changes in fasting insulin levels increased from the first to the fourth quartile (OR 1.15, 1.35, and 1.95 vs. 1.07, 1.22, and 1.41, respectively), after adjusting for multiple factors. The OR for hypertension was 2.0-fold higher in the high-high group and 1.34-fold higher in the low-high group than in the low-low group. In comparing the results by age group, we found that these relationships were more prominent in younger subjects.

CONCLUSION

High baseline and continuously increasing fasting insulin levels appeared to be independent determinants for the future development of hypertension during this 4-year follow-up study in normotensive, non-diabetic, healthy adults.

Elements of the metabolic syndrome: association with insulin sensitivity and effects of ethnicity

BACKGROUND

The objectives of the present study were, within a group of 322 healthy European American (EA) and African American (AA) women, to, (1) determine the extent to which insulin sensitivity (Si) was correlated with the elements of the metabolic syndrome using the third Adult Treatment Panel (ATP III) criteria; (2) determine if ethnicity affected the relationships between Si and the elements of the metabolic syndrome; and (3) determine the amount of variance in elements of the metabolic syndrome independently explained by fasting insulin, the acute insulin response to glucose (AIRg), and Si.

METHODS

Si and AIRg were assessed with a frequently-sampled intravenous glucose tolerance test and minimal modeling; total body fat with dual-energy x-ray absorptiometry; and intra-abdominal adipose tissue (IAAT) with computed tomography scanning.

RESULTS

Among all women combined, Si was associated with fasting glucose (r = -0.18, p < 0.01), waist circumference (r = -0.36, p < 0.001), and high-density lipoprotein cholesteraol (HDL-C; r = 0.18, p < 0.01). However, the association of Si with elements of the metabolic syndrome other than fasting glucose and waist circumference differed with ethnicity; among EA, Si was correlated with triglycerides (r = -0.28, p < 0.01) and HDL-C (r = 0.29, p < 0.001), whereas among AA, Si tended to be correlated with systolic blood pressure (r = -0.17, p = 0.059). In multiple regression modeling, fasting insulin was independently related to more elements of the metabolic syndrome (fasting glucose, waist circumference, triglycerides, systolic and diastolic blood pressure) than were Si or AIRg (both related only to fasting glucose), after adjusting for ethnicity, age, and total fat or IAAT.

CONCLUSIONS

Correlation of Si with elements of the metabolic syndrome differed with ethnic group. Fasting insulin, rather than Si, best predicted most elements of the metabolic syndrome.

Thiazolidinedione treatment decreases oxidative stress in spontaneously hypertensive heart failure rats through attenuation of inducible nitric oxide synthase-mediated lipid radical formation

The current study was designed to test the hypothesis that inducible nitric oxide synthase (iNOS)-mediated lipid free radical overproduction exists in an insulin-resistant rat model and that reducing the accumulation of toxic metabolites is associated with improved insulin signaling and metabolic response. Lipid radical formation was detected by electron paramagnetic resonance spectroscopy with in vivo spin trapping in an obese rat model, with or without thiazolidinedione treatment. Lipid radical formation was accompanied by accumulation of toxic end products in the liver, such as 4-hydroxynonenal and nitrotyrosine, and was inhibited by the administration of the selective iNOS inhibitor 1400 W. The model showed impaired phosphorylation of the insulin signaling pathway. Ten-day rosiglitazone injection not only improved the response to an oral glucose tolerance test and corrected insulin signaling but also decreased iNOS levels. Similar to the results with specific iNOS inhibition, thiazolidinedione dramatically decreased lipid radical formation. We demonstrate a novel mechanism where a thiazolidinedione treatment can reduce oxidative stress in this model through reducing iNOS-derived lipid radical formation. Our results suggest that hepatic iNOS expression may underlie the accumulation of lipid end products and that reducing the accumulation of toxic lipid metabolites contributes to a better redox status in insulin-sensitive tissues.

Characterization of metabolically unhealthy overweight/obese African American women: significance of insulin-sensitive and insulin-resistant phenotypes

BACKGROUND

Obesity is often associated with high cardiovascular disease risk factors. Obesity is common in African American women. We investigated the characteristics of metabolically healthy and metabolically unhealthy overweight/obese African American women based on the presence of insulin resistance.

MATERIALS/METHODS

We studied 196 apparently healthy overweight/obese African American women with family history of type 2 diabetes. Waist circumference, fasting glucose, insulin, c-peptide, lipids and lipoproteins, and systolic and diastolic blood pressure were obtained in each subject. In addition, insulin sensitivity was calculated using Bergman's Minimal Model Method. We defined insulin-sensitive metabolically healthy African American women as individuals with insulin sensitivity greater than 2.7 x 10(-4) x min(-1) (uU/ mL)(-1) and insulin resistant, metabolically unhealthy as insulin sensitivity less than 2.7 x 10(-4) x min(-1) (uU/mL)(-1).

RESULTS

Thirty-three percent of our subjects were metabolically healthy African American women, while 67% were metabolically unhealthy African American women. The metabolically healthy subjects were significantly younger and less obese than the metabolically unhealthy subgroup. Mean fasting serum glucose, insulin, and c-peptide were significantly lower (P = .001) in the metabolically healthy than in metabolically unhealthy subjects. However, the mean blood pressures were within normal in both subgroups. Mean serum cholesterol (p < .05) and triglyceride (p < .001) levels were significantly lower, whereas high-density lipoprotein cholesterol (p < .03) was significantly higher in the metabolically healthy than in the metabolically unhealthy subjects. We found 25.5% of our subjects had metabolic syndrome (30.3% metabolically unhealthy and 15.6% metabolically healthy).

CONCLUSION

We concluded that: (1) despite obesity, metabolically healthy African American women appear to be less prone to type 2 diabetes and cardiovascular disease and (2) in view of the higher prevalence of metabolic syndrome, metabolically unhealthy African American women should be targeted for primary prevention of type 2 diabetes and cardiovascular disease.

Hypertension, dyslipidemia, and insulin resistance in patients with diabetes mellitus or the cardiometabolic syndrome: benefits of vasodilating β-blockers

Hypertension frequently coexists with diabetes and the cardiometabolic syndrome. β-Blockers have been a mainstay for controlling blood pressure for nearly 4 decades. However, β-blockers are perceived to cause glucose and lipid metabolism dysregulation, including hypoglycemia masking, reduced glycemic control, insulin resistance, and dyslipidemia. It should be noted, however, that β-blockers are diverse in their effects on glucose and lipid metabolism. Potential mechanisms that contribute to these metabolic effects include hemodynamic differences, anti-inflammatory and anti-oxidative pathways, and/or weight changes. Traditional β-blockers decrease cardiac output while peripheral vascular resistance increases or remains unchanged, which may result in glucose and lipid abnormalities. In contrast, vasodilating β-blockers reduce peripheral vascular resistance but have little effect on cardiac output. Vasodilating β-blockers may therefore result in less impact on insulin sensitivity and glycemic control, a reduced new-onset diabetes risk, and improved dyslipidemia compared with traditional β-blockers. Because of these effects, vasodilating β-blockers may represent a favorable option in the treatment of high-risk patients with hypertension.

Alteration of vascular reactivity in diabetic human mammary artery and the effects of thiazolidinediones

Vascular reactivity was investigated in endothelium-denuded human internal mammary artery (IMA) rings from type 2 diabetic patients. It was also investigated whether insulin sensitizer thiazolidinedione drugs, pioglitazone and rosiglitazone, can directly affect the reactivity of IMA. Using organ bath techniques, cumulative concentration-response curves to phenylephrine (PE), KCl, cromakalim (CRO) and sodium nitroprusside (SNP) were constructed in diabetic and non-diabetic IMA rings. Means of maximal responses (% Emax) and pEC50 values (sensitivity) were compared. Emax values and the sensitivity to PE and KCl were increased while KATP-channel-mediated relaxations were reduced significantly in diabetic rings compared with non-diabetic rings (n = 5–12, P &lt; 0.05). No changes were observed for SNP responses (n = 5, P &gt; 0.05). Incubations with pioglitazone (1 and 10 μM) and rosiglitazone (1 and 20 μM), for 30 min, did not affect KATP-channel-mediated relaxations (n = 5 each, P &gt; 0.05). Pioglitazone partly inhibited pre-contractions of PE and KCl at 10 μM, rosiglitazone did not. Vascular dysfunction observed in diabetic IMA may be of specific importance since they are widely used as coronary bypass material. Thiazolidinedione drugs may not worsen arterial dilatation through KATP channels in ischaemic or hypoxic insults in diabetic patients who are prone to such conditions. Pioglitazone has vasorelaxant property in the grafts.

Changes in arterial blood pressure of a soluble cocoa fiber product in spontaneously hypertensive rats

The effect produced by long-term intake of a soluble cocoa fiber product (SCFP) on the development of hypertension of spontaneously hypertensive rats (SHR) was evaluated. Twenty male 3-week-old SHR were divided into two groups of 10 animals that drank either tap water (control) or a solution of SCFP (0.75 g/day SCFP) until the 20th week of life. Five 20-week-old rats of each group were sacrificed. Tap water as drinking fluid was given to all the animals from the 20th to 24th week of life. The 24-week-old rats were also sacrificed. Body weight, liquid and dry food intake, and arterial blood pressure (tail cuff) were recorded weekly. Malondialdehyde (MDA), glucose and angiotensin converting enzyme (ACE) activity in the plasma from the sacrificed rats were also obtained, and we evaluated the relaxation caused by acetylcholine in the aorta from these animals. SCFP attenuated the development of hypertension in SHR; however, the withdrawal of SCFP caused an increase in blood pressure in the rats. Body weight gain was slower in the group treated with SCFP. SCFP increased liquid intake but decreased dry food intake in the rats. SCFP decreased plasma MDA concentrations and slightly decreased plasma ACE activity, but no differences were observed in plasma glucose and in the aorta responses to acetylcholine in both groups of 20-week-old SHR. We have demonstrated the antihypertensive and antioxidant properties of SCFP. The control of body weight and the control of increased angiotensin II may be involved in the antihypertensive effect of this product.

Effect of body weight loss and normalization on blood pressure in overweight non-obese patients with stage 1 hypertension

We evaluated the effects of body weight (BW) loss on blood pressure (BP) in overweight non-obese patients with stage 1 hypertension. We enrolled 376 overweight (body mass index (BMI) >or=25 and <30 kg m(-2)) stage 1 hypertensive patients in this prospective 12-month trial. Each patient received tailored, low caloric dietary advice. After 6 months, patients with a BW reduction <5% were excluded. Body weight, BMI, BP, fasting plasma glucose (FPG), fasting plasma insulin (FPI), leptin (pL), renin and aldosterone levels were evaluated at baseline and after 6 and 12 months. In 222 patients who completed the study, a mean weight reduction of 8.1 kg reduced systolic blood pressure (SBP) by 4.2 mm Hg and diastolic blood pressure (DBP) by 3.3 mm Hg (P<0.05), which was accompanied by a significant decrease in FPI, pL and aldosterone levels (P<0.05). Larger SBP/DBP reductions were observed in 106 patients with normalized BMI (-5/-4.5 mm Hg, P<0.01) compared with the 116 patients who did not become normalized (-3.3/-1.6 mm Hg). The former also presented with greater decreases in FPG, FPI, pL, renin and aldosterone levels. Of the 106 patients who had normalized BMI, 52 also had normalized BP. Clinical and metabolic characteristics of these patients were similar to those of the 56 patients who did not have normalized BP. In overweight, mild hypertensive patients, weight loss was effective in reducing BP and in reversing some endocrinologic alterations associated with being overweight. Half of the patients who had normalized BMI also had normalized BP, which could indicate that these patients essentially did not have a form of hypertension but that these effects were instead secondary to being overweight.

Association of arterial hypertension with renal target organ damage in kidney transplant recipients: the predictive role of ambulatory blood pressure monitoring

BACKGROUND

Although arterial hypertension is a powerful predictor of graft failure, only few studies have evaluated 24-hr blood pressure (BP) profile in renal transplant recipients (RTRs).

METHODS

We performed ambulatory blood pressure monitoring (ABPM) in 94 RTRs (65 men; age 28-71 years) with 1-year functioning grafts. Serum biochemical parameters, daily proteinuria, and transplantation-related data were evaluated in all subjects.

RESULTS

ABPM showed that only 5% of RTRs were normotensives (BP<130/80 mm Hg) and identified 29% of patients with nocturnal hypertension. A strong, direct correlation was shown between each set of both systolic BP and diastolic BP measured by ABPM and serum creatinine, daily proteinuria, and serum triglycerides (P at least <0.025 for each). Serum creatinine immediately after transplantation and 1-yr asleep diastolic BP were the only significant predictors of 1-yr creatinine (P<0.0001; r=0.49), whereas awake systolic BP was the only predictor of daily proteinuria (r=0.39; P=0.005) by multiple regression analysis.

CONCLUSIONS

BP assessed by ABPM proved to be a stronger predictor of renal graft damage than traditional immunologic factors. ABPM improved the diagnostic accuracy of arterial hypertension in RTRs and was the only effective tool in disclosing the association of BP with 1-year renal transplant outcome.

How family history and risk factors for hypertension relate to ambulatory blood pressure in healthy adults

BACKGROUND

Although family history is a major predictor of hypertension, other risk factors have been linked to elevated blood pressure (BP). This study explored the relationship of norepinephrine (NE), insulin resistance and lipids to family history of hypertension, and attempted to determine the combined effects of family history and these factors on BP.

METHODS

A total of 220 healthy men and women, aged 22-50 years, completed two 24 h ambulatory BP sessions. Based on family history information obtained from parents, three groups were formed: subjects with two hypertensive parents, one hypertensive parent or normotensive parents. Plasma samples were obtained to derive fasting catecholamine levels, insulin, glucose and lipids.

RESULTS

Individuals with two hypertensive parents had high insulin, insulin resistance and low-density lipoprotein cholesterol. Although NE was not directly linked to family history, high NE levels were associated with increased BP, after controlling for family history and body mass index. Women with two hypertensive parents and elevated NE levels had higher systolic BP and diastolic BP during waking and sleep periods. In men the combination of two hypertensive parents and high NE was related only to diastolic BP during waking.

CONCLUSIONS

NE results provide evidence of sympathetic activation in the identification of individuals at risk for hypertension. Studying family history of hypertension and other risk factors in healthy individuals provides a unique opportunity to explore factors leading to elevated BP long before a diagnosis of hypertension is made.

Prevalence of the impaired glucose metabolism and its association with risk factors for coronary artery disease in women with gestational diabetes

Gestational diabetes (GDM) has increased risk of diabetes (DM2), a coronary artery disease (CAD) equivalent. The aim of this study was to determine the prevalence of impaired glucose metabolism (IGM) in GDM and its association with risk factors for CAD. A cohort of 109 women with GDM underwent a glucose tolerance test which classified them into three groups: diabetic (DM2) (fasting glucose (G) >or=126mg/dl or plasma glucose 2h (2-h G) >or=200mg/dl); impaired glucose tolerance (IGT) (G 100-125mg/dl and/or 2-h G 140-199mg/dl); and normal (N) (G<100mg/dl and/or 2-h<140mg/dl). They were compared for pre-gestational (PBMI) and current (CBMI) body mass index, systolic (SBP) and diastolic blood pressure (DBP), G, lipids, fibrinogen and C-reactive protein (hsCRP). Thirty two months after delivery, 17.4% presented DM2, 39.4% IGT and 43.1% were N. PBMI, CBMI, SBP and DBP were significantly higher in the DM2 than N. G was higher in DM2 and IGT. HDL-cholesterol (HDL-C) was higher in the N (p=0.02) and the triglycerides (TG) were higher in DM2 (p=0.02). The groups showed significantly different levels of hsCRP (p=0.002). We conclude that the high prevalence of IGM, overweight/obesity, dyslipidemia and altered inflammatory markers, make GDM a high-risk situation for CAD.

Arterial stiffness and haemodynamic response to vasoactive medication in subjects with insulin-resistance syndrome

INSR (insulin-resistance syndrome) affects 25% of the Australian population and is associated with increased cardiovascular risk. In the present study, we postulated that early cardiovascular changes in these individuals may be associated with an activated RAS (renin–angiotensin system). We studied 26 subjects: 13 with INSR [waist circumference, 99±6 cm; HOMA (homoeostasis model assessment) score, 2.5±0.3] and 13 NCs (normals controls; waist circumference, 77±2 cm; HOMA score, 1.4±0.2). All received intravenous GTN (glyceryl trinitrate; 10, 20 and 40 μg/min), L-NMMA (NG-monomethyl-L-arginine; 3 mg/kg of body weight), AngII (angiotensin II; 8 and 16 ng/min), the selective AT2R (AngII type 2 receptor) inhibitor PD123319 (10 and 20 μg/min) and AngII (16 ng/min)+PD123319 (20 μg/min). At the end of each infusion, arterial stiffness indices [SI (stiffness index) and RI (reflection index)] and haemodynamic parameters were measured. There was a significantly higher RI response to AngII (P=0.0004 for both 8 and 16 ng/min doses) and to PD123319 (P=0.004 and P=0.03 for 10 and 20 μg/min doses respectively) in subjects with INSR compared with NCs. Co-infusion of AngII and PD123319 did not lead to additive changes in RI. RI responses to L-NMMA and GTN were not significantly different in both groups. No significant differences in SI and haemodynamic responses were detected. In conclusion, AT1R (AngII type 1 receptor) and AT2R activity produce arterial stiffness changes in subjects with INSR. Evidence of increased AT1R- and AT2R-mediated responses in small-to-medium-sized arteries in INSR was found, and may play an early role in the pathogenesis of vascular changes in INSR before haemodynamic changes become apparent.

Impact of body mass index on blood pressure levels in patients with polycystic ovary syndrome

As there is controversy about the prevalence of hypertension in patients with polycystic ovary syndrome (PCOS) and, up to the present moment, no studies have evaluated the impact of body mass index (BMI) on blood pressure levels (BP) in these patients, we studied retrospectively sixty-nine patients with PCOS, with BMI of 29.0 ± 6.7 kg/m² and aged 25.6 ± 5.6 yr, subdivided into three groups according to BMI (normal, overweight and obese) and evaluated regarding BP (mercury sphygmomanometer), basal hormonal profile, fasting glucose, and insulin sensitivity (HOMA-IR). Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) were normal (118.1 ± 17.0 and 74.7 ± 11.5 mmHg, respectively), with a hypertension prevalence of 20.3%. Of these patients, 78.6% were obese and 21.4% were overweight. When the groups were compared according to BMI, a significant increase in SBP and DBP was observed (higher in overweight and obese patients for SBP and higher in obese for DBP), as well as a significant progressive increase in glucose, insulin, homeostatic model assessment, and a significant progressive decline in LH levels. When the patients were subdivided as normotensive or hypertensive, a significant difference was observed only for BMI (28.2 ± 6.1 and 34.7 ± 8.6 kg/m², respectively; p = 0.007). In conclusion, we observed a significant and progressive impact of BMI on blood pressure levels in our patients with polycystic ovary syndrome.

Essential hypertension seems to result from melatonin-induced epigenetic modifications in area postrema

Essential hypertension is a complex multifactorial disorder with epigenetic and environmental factors contributing to its prevalence. Epigenetic system is a genetic regulatory mechanism that allows humans to maintain extraordinarily stable patterns of gene expression over many generations. Sympathetic nervous system plays a major role in the maintenance of hypertension and the rostral ventrolateral medulla is the main source of this sympathetic activation. A possible mechanism to explain the sympathetic hyperactivity in the rostral ventrolateral medulla is an action of the area postrema. Area postrema seems to be the region where a shift of the set-point to a higher operating pressure occurs resulting in hypertension. But, how can a shift occur in the area postrema. We propose that melatonin-induced epigenetic modifications in the neurons of area postrema plays a role in this shift. Area postrema is reported to contain high levels of melatonin receptors that play a role in the epigenetic modifications in certain cells. Environmental stressors cause epigenetic modifications in the neurons of area postrema via the pineal hormone melatonin and these changes lead to a shift in the set-point to a higher operating pressure. This signal is then sent via efferent projections to key medullary sympathetic nuclei in rostral ventrolateral medulla resulting in increases in sympathetic nerve activity. This model may explain the long-term alterations in sympathetic activity in essential hypertension.

Type 2 diabetes in children: oxymoron or medical metamorphosis?

The full public health effects of the new epidemic of obesity and diabetes in children and adolescents may not be known for many years but are certain to be substantial. Diagnosed diabetes, which is present in only 4.2% of the US population, along with its consequences, already represents approximately 19% of the total personal healthcare expenditures in this country. Between 1997 and 2002, the estimated direct medical cost of diabetes increased from 44 billion dollars to 92 billion dollars, a staggering increase of 8 billion dollars a year. In 2002, diabetes annual costs per capita rose by more than 30% to 13,243 dollars per person, compared with the average annual health care costs for persons without diabetes of 2560.92 dollars. An estimate from the CDC indicates that approximately one-third of children born in 2000 will develop diabetes at some time in their life, and nearly one-half of all Hispanic children born in 2000 will develop diabetes. As type 2 diabetes is being diagnosed at an earlier age, more young people can expect to live many more years with diabetes and its complications, adding even further to this already enormous health burden. An appropriate starting place is recognition of the magnitude of the problem by physicians, politicians, public health policy makers, and other healthcare workers. An aggressive approach to management of diabetes must begin well before the appearance of cardiovascular, eye, renal, and other complications of diabetes appear, and even before obesity leads to diabetes. Currently, physicians and other healthcare workers are poorly reimbursed for management of obesity, for diabetes education, and for ongoing telephone contact with diabetic patients and families, essential for optimal diabetes management. National policies and priorities must be readjusted to emphasize prevention, rather than crisis management, if we are to avoid a catastrophic public health crisis within the next several decades.

Heart failure observation units: optimizing care

Heart failure causes substantial morbidity and mortality in the United States and accounts for a higher proportion of Medicare costs than any other disease. Most of these costs result from the high rate of hospital admissions and protracted length of stay associated with episodes of acute decompensation of heart failure. Thus, effective clinical strategies to obviate hospitalization and readmission can result in substantial savings. A specialized heart failure observation unit, in which patients receive rapid, goal-directed emergency care for heart failure symptoms, can be a critical component in this effort, providing intensive therapeutic monitoring and education. In institutions with specialized heart failure observation units, patients are triaged to this setting shortly after presentation to the emergency department (ED), and clinic referrals can be directed to this unit after minimal ED evaluation. Aggressive follow-up is also arranged at discharge. Recent additions to the therapeutic armamentarium and future advances in diagnostics and monitoring will continue to improve patient care and prevent avoidable hospitalizations.

Compromised arterial function in human type 2 diabetic patients

Diabetes is associated with a perturbation of signaling pathways in vascular tissue, which causes vasomotor dysfunction such as hypertension and accelerated atherosclerosis. In the present study, the mechanisms of vasomotor dysfunction, Akt (Thr308 and Ser473) phosphorylation and expression of endothelial NO (nitric oxide) synthase, and inducible NO synthase were investigated in human diabetic internal mammary arteries. The phospho-Akt (Thr308) level in arteries from diabetic patients was reduced to about one-half of the level in nondiabetic patients, suggesting impaired insulin signaling in human diabetic vascular tissue. Augmented vasoconstriction was observed in diabetic arteries, due in part to deficiency of basal and stimulated NO production. This correlated with decreased endothelial NO synthase expression and activity in diabetic vessels. The sensitivity of diabetic vessels to the NO donor, sodium nitroprusside, was reduced as well, suggesting that NO breakdown and/or decreased sensitivity of smooth muscle to NO are also responsible for abnormal vasoconstriction. In addition, the abnormal vasoconstriction in diabetic vessels was not completely abolished in the presence of Nomega-nitro-L-arginine methyl ester, revealing that NO-independent mechanisms also contribute to vasomotor dysfunction in diabetes. In conclusion, diabetes downregulates the Akt-signaling pathway and compromises human arterial function through a decrease in NO availability as well as through NO-independent mechanisms.

Role of exercise training on cardiovascular disease in persons who have type 2 diabetes and hypertension

Exercise training is an essential component in the medical management of patients who have type 2 diabetes and hypertension. Regular exercise improves the cardiovascular health of individuals who have these conditions through multiple mechanisms (Fig. 1). These mechanisms include improvements in endothelial vasodilator function,left ventricular diastolic function, arterial stiffness.systematic inflammation, and reducing left ventricular mass. Exercise training also reduces total and abdominal fat, which mediate improvements in insulin sensitivity and blood pressure, and possibly, endothelial function. Persons who are in a prediabetic stage or those who have the metabolic syndrome may be able to prevent or delay the progression to overt diabetes by adopting a healthier lifestyle, of which increasing habitual levels of physical activity isa vital component. Most persons who have diabetes and hypertension or are at risk for these conditions should be able to initiate an exercise program safely after appropriate medical screen-ing and the establishment of an individualized exercise prescription. Despite the increasing amount of evidence that shows the benefits of exercise training, this modality of prevention and treatment continues to be underused. Although patients' lack of knowledge of the benefits of exercise or lack of motivation contributes to this underuse, a lack of clear and specific guidelines from health care professionals also is an important factor. Clinicians need to educate patients about the benefits of exercise for managing their type 2 diabetes and assist in formulating specific advice for increasing physical activity. Specific instructions should be given to patients, rather than general advice, such as "you should exercise more often." Many cardiac re-habilitation and clinical exercise programs can accommodate patients who have type 2 diabetes and hypertension. Such programs can establish individualized exercise prescriptions and provide an environment that is conducive for "lifestyle change" that underlies long-term compliance to exercise and risk factor modification.

Pathobiology and cell interactions of platelets in diabetes

Diabetes is a well-recognised risk factor for atherosclerotic cardiovascular disease and in fact most diabetic patients die from vascular complications. The Diabetes Control and Complications Trial (DCCT) and the U.K. Prospective Diabetes Study (UKPDS) indicate a consistent relationship between hyperglycaemia and the incidence of chronic vascular complications in patients with diabetes. Platelets are essential for haemostasis, and abnormalities of platelet function may cause vascular disease in diabetes. Diabetic patients have hyperreactive platelets with exaggerated adhesion, aggregation and thrombin generation. In summary, the entire coagulation cascade is dysfunctional in diabetes. This review provides a comprehensive overview of the physiological role of platelets in maintaining haemostasis and of the pathophysiological processes that contribute to platelet dysfunction in diabetes and associated cardiovascular diseases, with special emphasis on proteomic approaches and leukocyte-platelet cross-talk.

[Characteristics of arterial hypertension in obesity]

INTRODUCTION

Arterial hypertension is the most frequent cardiovascular disease in obese persons, progressing with time to left ventricular hypertension, often associated with dilatation, diastolic disorders, hearth rhythm disturbance, and generalized atherosclerosis.

ETIOLOGY

The origin of this disease is related to hemodynamic disturbances (increased blood volume, minute volume, mainly due to increased stroke volume) accompanied with changes of peripheral resistance, which increases in a later phase. However, metabolic factors are presently considered as primarily responsible for appearance of hypertension, which has rightly obtained the attribute of metabolic hypertension. A key role belongs to insulin, in fact, to insulin resistance and hyperinsulinism.

TREATMENT

Awareness of the metabolic basis of arterial hypertension in obesity has resulted in a specific approach to its treatment. The primary treatment includes reduction diet, with a drastic reduction of salt intake and with compulsory physical activity, while concerning medications one should consider converting enzyme inhibitors, alpha1 blockers and calcium channel antagonists.

Novel PPARγ Agonists GI 262570, GW 7845, GW 1929, and Pioglitazone Decrease Calcium Channel Function and Myogenic Tone in Rat Mesenteric Arteries

Novel non-thiazolidinedione, tyrosine-derived peroxisome proliferator-activated receptor gamma agonists, GI 262570, GW 7845, GW 1929, developed by GlaxoSmithKline (GSK) along with pioglitazone and nisoldipine, were studied on currents through L-type voltage-dependent calcium channels (VDCC) in freshly isolated smooth muscle cells from mesenteric arteries, and on the diameter of pressurized mesenteric arteries in vitro. Using Ba2+ (10 mmol/l) as the charge carrier through VDCC, the half-inhibition constants (IC50) for GI 262570, GW 7845, GW 1929, and pioglitazone were 2.0 +/- 0.5, 3.0 +/- 0.5, 5.0 +/- 0.7, and 10.0 +/- 0.8 mumol/l, respectively. For arterial diameter measurements the IC50 values for GI 262570, GW 7845, GW 1929, and pioglitazone were 2.4, 4.1, 6.3, and 13.9 mumol/l, respectively. Each GSK compound and pioglitazone was effective at inhibiting VDCC and relaxing pressurized arteries, suggesting that the vasodilation of resistance arteries could be explained by the inhibition of calcium entry through VDCC.

Role of adiponectin in insulin-resistant hypertension and atherosclerosis

Insulin resistance is one of the major risk factors associated with development of hypertension and atherosclerosis. Recent studies have shown that adiponectin, an adipocyte-derived hormone, may be involved in insulin resistance and development of atherosclerosis in diabetes patients. The aim of this study was to examine adiponectin levels in patients with essential hypertension to determine the relationships between adiponectin levels and insulin sensitivity and to examine the relationship of adiponectin with pulse wave velocity (PWV) in a general population based on the results of an epidemiological survey in Japan. In a clinical study, 20 normotensives (NT) and 30 non-treated essential hypertensives (EHT) were hospitalized, and euglycemic hyperinsulinemic glucose clamp (GC) was performed to evaluate insulin sensitivity defined as M value. EHT were divided into insulin-resistant EHT (EHT-R) and insulin-nonresistant EHT (EHT-N) according to the mean -1 SD of the M value of NT as a cut-off point. Fasting plasma glucose (FPG), immunoreactive insulin (IRI), and adiponectin concentrations were measured. There were no significant differences in body mass index (BMI) or FPG among the NT, EHT-N, and EHT-R groups. The M value and adiponectin concentration in EHT-R were significantly lower than those in the NT or EHT-N. The IRI level in the EHT-R was significantly higher than those in the other groups. A positive correlation between adiponectin concentration and M value was found in all subjects, and adiponectin concentration and M value were found to be significant determinants of each other in multiple regression analysis. In an epidemiological study, we studied 391 male inhabitants of rural communities in Hokkaido, Japan. Systolic blood pressure (SBP), BMI, FPG, IRI, and adiponectin were measured in all subjects early in the morning. Homeostasis model assessment (HOMA) values were calculated as an index of insulin sensitivity, and PWV was used as an index of atherosclerosis. A negative correlation between HOMA values and adiponectin concentration was found in all of the subjects. Multiple regression analysis revealed that adiponectin was a significant determinant for PWV in subjects less than 70 years of age. The results of the clinical study indicate that EHT-R had not only hyperinsulinemia but also a low concentration of adiponectin. The results of multiple regression analysis for determinants of degree of PWV using data obtained in the epidemiological study suggest that adiponectin plays a role in antiatherosclerosis, partly through improvement of insulin resistance.

The effect of the PREMIER interventions on insulin sensitivity

OBJECTIVE

This ancillary study of PREMIER sought to determine the effects on insulin sensitivity of a comprehensive behavioral intervention for hypertension with and without the Dietary Approaches to Stop Hypertension (DASH) dietary pattern.

RESEARCH DESIGN AND METHODS

Participants were assigned to one of three nonpharmacologic interventions for blood pressure (group A, advice only; group B, established; and group C, established plus DASH). The established intervention included weight loss, reduced sodium intake, increased physical activity, and moderate alcohol intake; the DASH dietary pattern was added to the established intervention for those in group C. The DASH dietary pattern is high in fruits, vegetables, and low-fat dairy products while being lower in total fat, saturated fat, and cholesterol. It is abundant in nutrients such as magnesium, calcium, and protein, which have been associated with improved insulin sensitivity. Insulin sensitivity was measured at baseline and at 6 months using the frequently sampled intravenous glucose tolerance test with minimal model analysis.

RESULTS

Both intervention groups decreased total calories, percentage of calories from fat, and sodium intake to similar levels, with similar amounts of energy expenditure and weight loss. Covariate differences seen only in group C included increased intake of protein, potassium, calcium, and magnesium. Compared with control subjects, insulin sensitivity improved significantly only in group C, from 1.96 to 2.95 (P = 0.047). Group B did have a significant decrease in fasting insulin and glucose, but the changes in insulin sensitivity did not reach statistical significance when compared with control subjects.

CONCLUSIONS

These results suggest that including the DASH dietary pattern as part of a comprehensive intervention for blood pressure control enhances insulin action beyond the effects of a comprehensive intervention that does not include DASH.

Insulin-lowering agents in the management of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a medical condition that has brought multiple specialists together. Gynecologists, endocrinologists, cardiologists, pediatricians, and dermatologists are all concerned with PCOS patients and share research data and design clinical trials to learn more about the syndrome. Insulin resistance is a common feature of PCOS and is more marked in obese women, suggesting that PCOS and obesity have a synergistic effect on the magnitude of the insulin disorder. Hyperinsulinemia associated with insulin resistance has been causally linked to all features of the syndrome, such as hyperandrogenism, reproductive disorders, acne, hirsutism, and metabolic disturbances. Women with PCOS should be evaluated for cardiovascular risk factors, such as lipid profile and blood pressure. Modification of diet and lifestyle should be suggested to those who are obese. Several insulin-lowering agents have been tested in the management of PCOS. In particular, metformin is the only drug currently in widespread clinical use for treatment of PCOS. In a high percentage of patients, treatment with metformin is followed by regularization of menstrual cycle, reduction in hyperandrogenism and in cardiovascular risk factors, and improvement in response to therapies for induction of ovulation.

Pioglitazone reduces atherogenic dense LDL particles in nondiabetic patients with arterial hypertension: a double-blind, placebo-controlled study

OBJECTIVE

The oral antidiabetic agent pioglitazone improves insulin sensitivity and glycemic control and appears to lower atherogenic dense LDL in type 2 diabetes. Insulin resistance may occur frequently in nondiabetic patients with hypertension. This study is the first to report the effect of pioglitazone on LDL subfractions in normolipidemic, nondiabetic patients with arterial hypertension.

RESEARCH DESIGN AND METHODS

We performed a monocentric, double-blind, randomized, parallel-group comparison of 45 mg pioglitazone (n = 26) and a placebo (n = 28), each given once daily for 16 weeks. Fifty-four moderately hypertensive patients (LDL cholesterol, 2.8 +/- 0.8 mmol/l; HDL cholesterol, 1.1 +/- 0.3 mmol/l; triglycerides, 1.4 mmol/l (median; range 0.5-7.1) were studied at baseline and on treatment.

RESULTS

At baseline, dense LDLs were elevated (apolipoprotein [apo]B in LDL-5 plus LDL-6 >250 mg/l) in 63% of all patients. Sixteen weeks of treatment with pioglitazone did not significantly change triglycerides, total, LDL, and HDL cholesterol. However, pioglitazone reduced dense LDLs by 22% (P = 0.024). The mean diameter of LDL particles increased from 19.83 +/- 0.30 to 20.13 +/- 0.33 nm (P < 0.001 vs. placebo), whereas the mean LDL density decreased from 1.0384 +/- 0.0024 to 1.0371 +/- 0.0024 kg/l (P = 0.005 vs. placebo). The effect of pioglitazone on LDL size and density was independent of fasting triglycerides and HDL cholesterol at baseline and of changes in fasting triglycerides and HDL cholesterol.

CONCLUSIONS

The prevalence of atherogenic dense LDL in nondiabetic, hypertensive patients is similar to patients with type 2 diabetes. Pioglitazone significantly reduces dense LDL independent from fasting triglycerides and HDL cholesterol. The antiatherogenic potential of pioglitazone may thus be greater than that expected from its effects on triglycerides, LDL, and HDL cholesterol alone.

The insulin resistance syndrome and coronary artery disease

Insulin resistance is an increasingly common metabolic abnormality characterized by an impaired physiological response to insulin. The constellation of insulin resistance and several other metabolic and vascular disorders is known as the insulin resistance syndrome. The characteristic features of the insulin resistance syndrome include central obesity, hypertension, dyslipidemia, glucose intolerance and specific abnormalities of both endothelial cell and vascular function. Although insulin resistance can arise in response to aging, obesity and inactivity, there is a clear genetic component. Insulin resistance is not generally attributable to a single genetic defect. Indeed, it is very likely to be a polygenic disorder in most individuals. A genetic predisposition is suggested to be the demonstration of increased insulin resistance in first-degree relatives of patients with diabetes and by a high incidence of insulin resistance in specific populations. Epidemiological data have demonstrated a strong association between a clustering of specific factors and the risk of cardiovascular disease. The diagnosis of the insulin resistance syndrome remains a significant clinical challenge. At present, clinicians are faced with establishing a clinical diagnosis despite varying definitions of the disorder and controversy regarding how many components presage clinical events. A proposed approach to the management of patients with the insulin resistance syndrome is discussed.

Diabetes mellitus and diabetes-associated vascular disease

Diabetes-related cardiovascular disease remains the leading cause of death in patients with type 2 diabetes. Hypertension is common among diabetics and has the same pathogenetic mechanisms as insulin resistance, in which the activated renin-angiotensin system contributes to the emerging high blood pressure and hyperglycemia. Hyperglycemia is one of the triggering factors for vascular dysfunction and clotting abnormalities and, therefore, for accelerated atherosclerosis in diabetes. Glycated hemoglobin levels, as a reflection of the degree of glycemia, are strongly associated with the risk of cardiovascular disease in diabetics and in the general population. Tight glycemic control, the treatment of dyslipidemia and raised blood pressure, in addition to the use of antiplatelet therapy, all powerfully reduce the risks associated with diabetes. Furthermore, angiotensin-converting enzyme inhibitors might offer additional cardioprotection to diabetics above that provided by blood pressure reduction.

Post-transplant diabetes mellitus: increasing incidence in renal allograft recipients transplanted in recent years

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a serious complication of transplantation caused by immunosuppressive drugs. In this study, we assessed the incidence of PTDM and the factors that are associated with the development of this complication.

METHODS

The study population included 2078 non-DM renal allograft recipients, transplanted since 1983 in one institution. PTDM was diagnosed by the requirement of hypoglycemic medications, starting more than 30 days after transplantation. Post-transplant, all patients received cyclosporine (CsA) and prednisone, but none of these patients received tacrolimus.

RESULTS

At 1, 3, 5, and 10 years after transplantation, 7, 10, 13, and 21% of patients developed PTDM. By multivariate Cox, the following variables correlated with a more rapid increase in the number of PTDM cases: (1) older age (RR = 2.2 comparing patients younger or older than 45 years, P < 0.0001), (2) transplant done after 1995 (RR = 1.7, P = 0.003), (3) African American race (RR = 1.6, P = 0.003), and (4) higher body weight at transplant (RR = 1.4, P < 0.0001). Compared with before 1995, since 1995, the percentage of patients with PTDM has increased from 5.9 to 10.5% at one year and from 8.8 to 16.9% at three years. This increase was statistically independent from all other variables tested. However, since 1995, recipients have become significantly heavier (P < 0.0001) and older (P < 0.0001), and the average CsA level has increased significantly (P < 0.0001). Also, since 1995, the cumulative dose of corticosteroids has declined (P < 0.0001); patients received a newer, better absorbed preparation of CsA and received mycophenolate mofetil.

CONCLUSIONS

The risk of PTDM increases continuously with time post-transplant. There has been an increase in the incidence of PTDM in patients transplanted recently, and that increase can be explained only partially by changes in the recipients' characteristics. We postulate that this increase may be due to the introduction of better absorbed CsA formulations that result in higher blood levels and higher cumulative exposure to this diabetogenic drug.

Sympathetic nervous system, diabetes, and hypertension

Hypertension is twice as frequent in diabetic patients than in the general population. Its prevalence is higher in Type 2 than in Type 1 diabetes: in the former, the onset of hypertension often precedes the diagnosis of diabetes, whereas, in the latter it is strictly related to the presence of nephropathy. Sympathetic nerve overactivity is crucial in the pathogenesis of hypertension in diabetes. It can be related to the activation of the renin-angiotensin-aldosterone (RAA) system in Type 1 diabetic patients with chronic renal failure, or to a condition of insulin resistance/hyperinsulinemia in Type 2 patients with the metabolic syndrome. In patients with early autonomic neuropathy, vagal impairment can lead to a relative predominance of sympathetic activity in the sympatho-vagal balance. In these patients, the onset of hypertension is frequently preceded by reduced nocturnal dipping. Sympathetic overactivity stimulates RAA activity, promotes sodium reabsorption, and increases heart rate, stroke volume and peripheral vascular resistance, thus inducing hypertension and increasing cardiovascular risk. A number of drugs acting either directly or indirectly on sympathetic activity are available for the treatment of hypertension in diabetic subjects. Opinions on the potential advantages of the metabolic profile of some of these drugs are as yet conflicting.

Portal venous and enteric exocrine drainage versus systemic venous and bladder exocrine drainage of pancreas grafts: clinical outcome of 40 consecutive transplant recipients

OBJECTIVE

To test the hypothesis that pancreas transplantation using the more physiologic method of portal venous-enteric (PE) drainage could be performed without compromising patient and graft outcome, compared with the standard method of systemic venous-bladder (SB) drainage.

METHODS

Between November 1995 and November 1998, the authors prospectively followed up 20 consecutive patients with SB drainage followed by 20 consecutive patients with PE drainage. All patients underwent simultaneous pancreas-kidney transplantation, and all were immunosuppressed with antilymphocyte serum, cyclosporin, azathioprine, and steroids.

RESULTS

The actuarial patient survival rate at 1 year was 95% in the SB group and 100% in the PE group. Death-censored kidney graft survival was 100% in both groups; pancreas graft survival was 95% in the SB group and 100% in the PE group. The mean initial hospital stay was 15 days for both groups. However, during the first 6 months after transplantation, the SB group required more medical day-unit visits, mostly for treatment of metabolic acidosis and dehydration. The incidence of urinary tract infections was similar in both groups. The incidence of cytomegalovirus infections was significantly less in the PE group. The incidence of acute rejection was 37% in the SB group and 15% in the PE group. Mean serum creatinine levels 6 months after transplantation were significantly lower in the PE group than in the SB group. Glycemic control was excellent in both groups, but fasting serum insulin levels were significantly lower in the PE group.

CONCLUSIONS

The PE method of pancreas transplantation can be performed with excellent patient and graft outcomes.

Visceral obesity and metabolic syndrome

There is increasing evidence for the existence of a condition consisting of a cluster of metabolic disorders which include insulin resistance, alterations in glucose and lipid metabolism, increased blood pressure and visceral obesity. The metabolic syndrome is now the favoured definition of the cluster. Each single component of the cluster increases the cardiovascular risk, but the combination of factors is much more important. Insulin resistance is the most frequently associated factor to the singular components of the syndrome: most authors believe that it may be the common aetiological factor. However, visceral obesity seems to be the main driving factor by means of the increased production of free fatty acids whose activity, in turn, might interfere with the action of insulin. Some questions exist about the syndrome because of the frequent lack in the cluster of one of the factors. This does not mean that the missing factor does not belong to the syndrome, but only that it is not yet clinically evident. Weight gain has been shown to be a strong predictor of the metabolic syndrome. This aspect gives strength to treatment and prevention because it means that losing weight or stopping weight increase might reduce the risk of a future appearance of a factor that is still not evident. Interventions to treat visceral obesity by means of losing weight seem to be the most efficacious way to treat the metabolic syndrome thus improving the most widespread cardiovascular risk factor in western countries.