Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system

Losartan increases muscle insulin delivery and rescues insulin's metabolic action during lipid infusion via microvascular recruitment

Insulin delivery and transendothelial insulin transport are two discrete steps that limit muscle insulin action. Angiotensin II type 1 receptor (AT1R) blockade recruits microvasculature and increases glucose use in muscle. Increased muscle microvascular perfusion is associated with increased muscle delivery and action of insulin. To examine the effect of acute AT1R blockade on muscle insulin uptake and action, rats were studied after an overnight fast to examine the effects of losartan on muscle insulin uptake (protocol 1), microvascular perfusion (protocol 2), and insulin's microvascular and metabolic actions in the state of insulin resistance (protocol 3). Endothelial cell insulin uptake was assessed, using (125)I-insulin as tracer. Systemic lipid infusion was used to induce insulin resistance. Losartan significantly increased muscle insulin uptake (∼60%, P < 0.03), which was associated with a two- to threefold increase in muscle microvascular blood volume (MBV; P = 0.002) and flow (MBF; P = 0.002). Losartan ± angiotensin II had no effect on insulin internalization in cultured endothelial cells. Lipid infusion abolished insulin-mediated increases in muscle MBV and MBF and lowered insulin-stimulated whole body glucose disposal (P = 0.0001), which were reversed by losartan administration. Inhibition of nitric oxide synthase abolished losartan-induced muscle insulin uptake and reversal of lipid-induced metabolic insulin resistance. We conclude that AT1R blockade increases muscle insulin uptake mainly via microvascular recruitment and rescues insulin's metabolic action in the insulin-resistant state. This may contribute to the clinical findings of decreased cardiovascular events and new onset of diabetes in patients receiving AT1R blockers.

ANG II causes insulin resistance and induces cardiac metabolic switch and inefficiency: a critical role of PDK4

The renin-angiotensin system (RAS) may alter cardiac energy metabolism in heart failure. Angiotensin II (ANG II), the main effector of the RAS in heart failure, has emerged as an important regulator of cardiac hypertrophy and energy metabolism. We studied the metabolic perturbations and insulin response in an ANG II-induced hypertrophy model. Ex vivo heart perfusion showed that hearts from ANG II-treated mice had a lower response to insulin with significantly reduced rates of glucose oxidation in association with increased pyruvate dehydrogenase kinase 4 (PDK4) levels. Palmitate oxidation rates were significantly reduced in response to insulin in vehicle-treated hearts but remained unaltered in ANG II-treated hearts. Furthermore, phosphorylation of Akt was also less response to insulin in ANG II-treated wild-type (WT) mice, suggestive of insulin resistance. We evaluated the role of PDK4 in the ANG II-induced pathology and showed that deletion of PDK4 prevented ANG II-induced diastolic dysfunction and normalized glucose oxidation to basal levels. ANG II-induced reduction in the levels of the deacetylase, SIRT3, was associated with increased acetylation of pyruvate dehydrogenase (PDH) and a reduced PDH activity. In conclusion, our findings show that a combination of insulin resistance and decrease in PDH activity are involved in ANG II-induced reduction in glucose oxidation, resulting in cardiac inefficiency. ANG II reduces PDH activity via acetylation of PDH complex, as well as increased phosphorylation in response to increased PDK4 levels.

Prevention of cardiovascular complications of the metabolic syndrome: focus on pharmacotherapy

The metabolic syndrome increases the risk of atherothrombotic cardiovascular disease (CVD) and diabetes. In turn, diabetes promotes the development of atheroma and is regarded as a coronary heart disease risk equivalent. A multifactorial therapeutic strategy is advocated for patients with the metabolic syndrome to improve cardiovascular risk factor profiles and to reduce the chances of developing type 2 diabetes. Individual components of the syndrome must be addressed using safe, efficacious, and cost-effective measures. There is general agreement that lifestyle modifications, including control of body weight, avoidance of central adiposity, adoption of an antiatherogenic diet, and regular physical activity, are crucial. However, as the magnitude of the individual components of the metabolic syndrome increases with time, lifestyle measures are often insufficient. An individual with metabolic syndrome will often require drug treatment for hyperglycemia, atherogenic dyslipidemia, and high blood pressure, together with antiplatelet therapy. Reducing the need for polypharmacy is an increasingly important consideration for clinicians and the pharmaceutical industry; to date, no single therapy has emerged that targets the root cause(s) of the syndrome. HMG-CoA reductase inhibitors are important agents that reduce CVD morbidity and mortality, in people with impaired fasting glucose or metabolic syndrome. Selective cannabinoid receptor antagonists appear promising because they improve or attenuate several key defects of the syndrome. Thiazolidinediones and metformin are presently licensed for treatment of type 2 diabetes but may prove to have a broader role in future. Novel insulin-sensitizing drugs are under investigation. Drugs that act to prevent or reverse endothelial dysfunction may be of particular utility in preventing cardiovascular disease, especially if initiated before tissue damage has become irreversible. Insulin therapy, which has antiinflammatory and endothelial protective properties, has been shown to reduce morbidity and mortality in high-risk nondiabetic patients during critical illness. Potential synergy between different classes of drugs with metabolic and/or cardiovascular protective properties merits further investigation.

Insulin sensitization therapy and the heart: focus on metformin and thiazolidinediones

Chronic heart failure (CHF) is an insulin-resistant (IR) state and the degree of IR is related to disease severity and poor clinical outcome in CHF. IR may be pathophysiologically linked with CHF. Therefore, IR may represent a new target for treatment in CHF. Metformin and thiazolidinediones (TZDs) are effective diabetic therapies that are insulin sensitizers. TZDs are contraindicated in CHF because their use is associated with increased incidence of CHF as a result of their effects on renal sodium reabsorption and vascular permeability. There is evidence to suggest that metformin may be both safe and useful in CHF.

Long-term impact of multifactorial treatment on new-onset diabetes and related cardiovascular events in metabolic syndrome: a post hoc ATTEMPT analysis

This post hoc analysis of the Assessing The Treatment Effect in Metabolic Syndrome Without Perceptible diabeTes (ATTEMPT) study assesses the 3½ year incidence of new-onset diabetes (NOD) and related cardiovascular disease (CVD) events in patients with metabolic syndrome (MetS), after multifactorial (lifestyle and drug, including atorvastatin) intervention. Patients were randomized to group A (low-density lipoprotein cholesterol [LDL-C] target < 100 mg/dL) and group B (< 130 mg/dL). The incidence of NOD during the 42-month follow-up was very low, 0.83 to 1.00/100 patient-years in patients with MetS and MetS with impaired fasting glucose, respectively. Older age, increased waist circumference, and persistent MetS were determinants of NOD. One CVD nonfatal event occurred in the 28 patients with NOD. Our findings suggest that treating the characteristics of MetS is achievable and beneficial. New-onset diabetes incidence and CVD events were negligible and not different from what is expected in the general population.

Higher plasma renin activity is a risk factor for total mortality in older Japanese individuals: the Takahata study

Plasma renin activity (PRA) is accepted as a marker for increased risk of cardiovascular diseases. However, the association between PRA and total mortality has not been fully explored in a general population. We here examined whether PRA is associated with increased total mortality in a general Japanese population. The participants of the Takahata study (3502 subjects; age, 62.5 ± 10.4 years), a population-based, longitudinal study of Japanese held from 2004 to 2006, were enrolled and followed up for up to 7 years. The incidence of death and causes of death were monitored annually to the end of 2010 (median follow-up, 2280 days). During the follow-up period, 143 subjects died. Kaplan-Meier analysis showed a significantly increased risk for total mortality in subjects with higher PRA (log-rank P < .001). Cox proportional hazard model analyses with adjustment for factors correlated with PRA (age, sex, weight, diastolic blood pressure, high-density lipoprotein cholesterol, uric acid, B-type natriuretic peptide, serum total protein, antihypertensive treatment, and diabetes) showed that higher PRA was associated with increased total mortality in linear regression models (per 1 increase in log 10 × PRA [nanograms per milliliter per hour]: hazard ratio, 2.12; 95% confidence interval, 1.47-3.06), between groups of patients stratified by quartiles of PRA (highest vs lowest quartile: 2.63, 1.57-4.41) and in subjects with high (≥ 2.0 ng/[mL h]) vs low (<2.0 ng/[mL h]) PRA (1.97, 1.37-2.83). Higher PRA was a significant and independent risk factor for increased total mortality in this Japanese population and may be a marker for subjects at an increased risk of total mortality.

Differential effects of nebivolol and metoprolol on insulin sensitivity and plasminogen activator inhibitor in the metabolic syndrome

Early-generation β-blockers lower blood pressure and reduce cardiovascular morality in coronary artery disease and congestive heart failure but worsen glucose homeostasis and fibrinolytic balance. Nebivolol is a third-generation β-blocker that increases the bioavailability of nitric oxide. We compared the effect of nebivolol (5 mg/d) and the β(1)-selective antagonist metoprolol (100 mg/d) on glucose homeostasis and markers of fibrinolysis in 46 subjects with metabolic syndrome. Subjects underwent a frequently sampled IV glucose tolerance test after 3-week washout and placebo treatment and after randomized treatment with study drug. After 12-week treatment, nebivolol and metoprolol equivalently decreased systolic blood pressure, diastolic blood pressure, and heart rate. Neither drug affected β-cell function, disposition index, or acute insulin response to glucose. Metoprolol significantly decreased the insulin sensitivity index. In contrast, nebivolol did not affect insulin sensitivity, and the decrease in sensitivity was significantly greater after metoprolol than after nebivolol (-1.5±2.5×10(-4)×min(-1) per milliunit per liter versus 0.04±2.19×10(-4)×min(-1) per milliunit per liter after nebivolol; P=0.03). Circulating plasminogen activator inhibitor also increased after treatment with metoprolol (from 9.8±6.8 to 12.3±7.8 ng/mL) but not nebivolol (from 10.8±7.8 to 10.5±6.2 ng/mL; P=0.05 versus metoprolol). Metoprolol, but not nebivolol, increased F(2)-isoprostane concentrations. In summary, treatment with metoprolol decreased insulin sensitivity and increased oxidative stress and the antifibrinolytic plasminogen activator inhibitor 1 in patients with metabolic syndrome, whereas nebivolol lacked detrimental metabolic effects. Large clinical trials are needed to compare effects of nebivolol and the β(1) receptor antagonist metoprolol on clinical outcomes in patients with hypertension and the metabolic syndrome.

Elevation of the antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline: a blood pressure-independent beneficial effect of angiotensin I-converting enzyme inhibitors

Blockade of the renin-angiotensin system (RAS) is well recognized as an essential therapy in hypertensive, heart, and kidney diseases. There are several classes of drugs that block the RAS; these drugs are known to exhibit antifibrotic action. An analysis of the molecular mechanisms of action for these drugs can reveal potential differences in their antifibrotic roles. In this review, we discuss the antifibrotic action of RAS blockade with an emphasis on the potential importance of angiotensin I-converting enzyme (ACE) inhibition associated with the antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP).

Review article: pancreatic renin-angiotensin systems in health and disease

BACKGROUND

In addition to the circulating (endocrine) renin-angiotensin system (RAS), local renin-angiotensin systems are now known to exist in diverse cells and tissues. Amongst these, pancreatic renin-angiotensin systems have recently been identified and may play roles in the physiological regulation of pancreatic function, as well as being implicated in the pathogenesis of pancreatic diseases including diabetes, pancreatitis and pancreatic cancer.

AIM

To review and summarise current knowledge of pancreatic renin-angiotensin systems.

METHODS

We performed an extensive PubMed, Medline and online review of all relevant literature.

RESULTS

Pancreatic RAS appear to play various roles in the regulation of pancreatic physiology and pathophysiology. Ang II may play a role in the development of pancreatic ductal adenocarcinoma, via stimulation of angiogenesis and prevention of chemotherapy toxicity, as well as in the initiation and propagation of acute pancreatitis (AP); whereas, RAS antagonism is capable of preventing new-onset diabetes and improving glycaemic control in diabetic patients. Current evidence for the roles of pancreatic RAS is largely based upon cell and animal models, whilst definitive evidence from human studies remains lacking.

CONCLUSIONS

The therapeutic potential for RAS antagonism, using cheap and widely available agents, and may be untapped and such roles are worthy of active investigation in diverse pancreatic disease states.

Oxidative stress as pathogenesis of cardiovascular risk associated with metabolic syndrome

Metabolic syndrome (MetS) is characterized by accumulation of visceral fat associated with the clustering of metabolic and pathophysiological cardiovascular risk factors: impaired glucose tolerance, dyslipidemia, and hypertension. Although the definition of MetS is different among countries, visceral obesity is an indispensable component of MetS. A growing body of evidence suggests that increased oxidative stress to adipocytes is central to the pathogenesis of cardiovascular disease in MetS. Increased oxidative stress to adipocytes causes dysregulated expression of inflammation-related adipocytokines in MetS, which contributes to obesity-associated vasculopathy and cardiovascular risk primarily through endothelial dysfunction. The purpose of present review is to unravel the mechanistic link between oxidative stress and cardiovascular risk in MetS, focusing on insulin resistance, hypertension, and atherosclerosis. Then, therapeutic opportunities translated from the bench to bedside will be provided to develop novel strategies to cardiovascular risk factors in MetS.

The renin-angiotensin-aldosterone system and glucose homeostasis

The renin-angiotensin-aldosterone system (RAAS) is inappropriately activated in obesity. In individuals at risk for diabetes, RAAS inhibition protects against kidney and heart disease, and also reduces the incidence of diabetes in large clinical trials. At a cellular level, angiotensin II (Ang II) and aldosterone induce insulin resistance by increasing oxidative stress and altering insulin signaling, leading to decreased glucose transport. Ang II also contributes to oxidative stress, inflammation, and apoptosis in pancreatic β cells. Aldosterone diminishes glucose-stimulated insulin secretion in vivo and in vitro from isolated pancreatic islets and cultured β cells through a mineralocorticoid receptor (MR)-independent mechanism. We review these findings in the context of pharmacological strategies interrupting the RAAS to highlight the potential application of these strategies to the prevention of diabetes progression.

Renin-Angiotensin-aldosterone system in diabetes and hypertension

Activation of the renin-angiotensin-aldosterone system (RAAS) is the primary etiologic event in the development of hypertension in people with diabetes mellitus. Modulation of the RAAS has been shown to slow the progression and even cause regression of the microvascular and macrovascular complications associated with diabetes mellitus. Early pharmacotherapy with agents that decrease RAAS activation in the adipose tissue have had a dramatic impact on the prevalence of diabetes related complications. Recent data show that preventing the development of "angry fat" can prevent not just hypertension but also type 2 diabetes mellitus and its associated complications. This review updates what is known about angry fat and the role of RAAS inhibition in preventing the metabolic sequelae of local RAAS activation.

Aldosterone decreases glucose-stimulated insulin secretion in vivo in mice and in murine islets

AIMS/HYPOTHESIS

Aldosterone concentrations increase in obesity and predict the onset of diabetes. We investigated the effects of aldosterone on glucose homeostasis and insulin secretion in vivo and in vitro.

METHODS

We assessed insulin sensitivity and insulin secretion in aldosterone synthase-deficient (As [also known as Cyp11b2](-/-)) and wild-type mice using euglycaemic-hyperinsulinaemic and hyperglycaemic clamps, respectively. We also conducted studies during high sodium intake to normalise renin activity and potassium concentration in As (-/-) mice. We subsequently assessed the effect of aldosterone on insulin secretion in vitro in the presence or absence of mineralocorticoid receptor antagonists in isolated C57BL/6J islets and in the MIN6 beta cell line.

RESULTS

Fasting glucose concentrations were reduced in As (-/-) mice compared with wild-type. During hyperglycaemic clamps, insulin and C-peptide concentrations increased to a greater extent in As (-/-) than in wild-type mice. This was not attributable to differences in potassium or angiotensin II, as glucose-stimulated insulin secretion was enhanced in As (-/-) mice even during high sodium intake. There was no difference in insulin sensitivity between As (-/-) and wild-type mice in euglycaemic-hyperinsulinaemic clamp studies. In islet and MIN6 beta cell studies, aldosterone inhibited glucose- and isobutylmethylxanthine-stimulated insulin secretion, an effect that was not blocked by mineralocorticoid receptor antagonism, but was prevented by the superoxide dismutase mimetic tempol.

CONCLUSIONS/INTERPRETATION

We demonstrated that aldosterone deficiency or excess modulates insulin secretion in vivo and in vitro via reactive oxygen species and in a manner that is independent of mineralocorticoid receptors. These findings provide insight into the mechanism of glucose intolerance in conditions of relative aldosterone excess.

Effect of pioglitazone and ramipril on biomarkers of low-grade inflammation and vascular function in nondiabetic patients with increased cardiovascular risk and an activated inflammation: results from the PIOace study

AIMS

This study investigated the effects of pioglitazone (PIO), ramipril (RAM), or their combination (PIRA) on low-grade inflammation in nondiabetic hypertensive patients with increased cardiovascular risk.

METHODS AND RESULTS

Patients enrolled in this placebo-controlled, double-blind, randomized, parallel trial (72 male, 77 female, aged 60 ± 9 years, body mass index 30.4 ± 4.7 kg/m(2), duration of hypertension 9 ± 8 years) were treated with either 30/45 mg PIO (dose titration), 2.5/5 mg RAM, or their combination for 12 weeks. A reduction in high-sensitivity C-reactive protein was observed with PIO (-0.89 ± 1.98 mg/liter; -25%) and PIRA (-0.49 ± 2.11 mg/liter; -16%), while an increase was seen with RAM (0.58 ± 2.13 mg/liter; +20%, p < .05 vs PIO and PIRA). The 24-hour blood pressure profile showed a small increase with both monotherapies but a decrease with PIRA (p < .05 vs PIO). Improvements in biomarkers of chronic systemic inflammation and insulin resistance (IR) were observed in the PIO and PIRA arms only [PIO/RAM/PIRA: homeostasis model of assessment of IR: -0.78 ± 1.39 (-29%)/0.15 ± 1.03 (+5%)/ -1.44 ± 2.83 (-40%); adiponectin: 8.51 ± 5.91 (+104%)/ 0.09 ± 2.63 (+1%)/ 8.86 ± 6.37 mg/liter (+107%); matrix metallo-proteinase-9: -48 ± 127 (-12%)/-1 ± 224 (0%)/-60 ± 210 ng/ml (-13%), p < .05 for RAM vs PIO or PIRA in all cases].

CONCLUSIONS

Our 3-month study in nondiabetic hypertensive patients showed a decrease in biomarkers of IR and chronic systemic inflammation with the PIO monotherapy and the PIRA combination only, which may help to explain some findings in other cardiovascular outcome trials.

Angiotensin II type 1 receptor antagonists in the treatment of hypertension in elderly patients: focus on patient outcomes

Hypertension in the elderly is one of the main risk factors of cardiovascular and cerebrovascular diseases. Knowledge regarding the mechanisms of hypertension and specific considerations in managing hypertensive elderly through pharmacological intervention(s) is fundamental to improving clinical outcomes. Recent clinical studies in the elderly have provided evidence that angiotensin II type 1 (AT(1)) receptor antagonists can improve clinical outcomes to a similar or, in certain populations, an even greater extent than other classical arterial blood pressure-lowering agents. This newer class of antihypertensive agents presents several benefits, including potential for improved adherence, excellent tolerability profile with minimal first-dose hypotension, and a low incidence of adverse effects. Thus, AT(1) receptor antagonists represent an appropriate option for many elderly patients with hypertension, type 2 diabetes, heart failure, and/or left ventricular dysfunction.

Association of angiotensin II type 1 receptor gene A1166C polymorphism with the presence of diabetes mellitus and metabolic syndrome in patients with documented coronary artery disease

BACKGROUND

There are relatively limited data available on the genetic susceptibility to diabetes mellitus and metabolic syndrome in the Iranian population. We have therefore investigated the association between the angiotensin II type I receptor gene polymorphism (AT(1)R/A1166C) and the presence of diabetes mellitus and metabolic syndrome in a well defined group of patients.

METHODS

Patients with angiographically defined coronary artery disease (CAD) (n=309) were evaluated for the presence of AT(1)R/A1166C polymorphism. These patients were classified into subgroups with (n=164, M/F: 109/55) and without (n=145, M/F: 84/61) diabetes mellitus. The AT(1)R polymorphism was assessed using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based method.

RESULTS

There was a higher frequency of polymorphic genotypes (AC+CC) in the diabetic compared with the non-diabetic group (p=0.01). When determined for each gender separately, this difference remained significant in the males (p=0.04) but not in females (p=0.09). With regard to the allele frequencies, the C allele was significantly higher and the A allele frequency was lower in the diabetic group (p=0.01). This remained significant after gender segregation for males (p=0.01) but not females. In the binary logistic regression analysis, only serum fasting glucose was found as the independent predictor for the presence of diabetes in the CAD patients (β=1.16, p<0.001 for total population and β=1.29, p<0.001 for male subjects). There was no significant difference in genotype or allele frequencies between subgroups with and without metabolic syndrome, this being unaffected by gender or the definition of metabolic syndrome used apart from a significantly lower frequency of C allele in male subjects with metabolic syndrome defined by the NCEP ATP III criteria (p=0.04).

CONCLUSION

The AT(1)R/A1166C polymorphism may be associated with the presence of diabetes mellitus in male subjects with documented CAD.

An update on the islet renin-angiotensin system

The traditional renin-angiotensin system (RAS) components have been studied extensively since the rate-limiting component of RAS, renin, was first characterized. The ongoing identification of various novel RAS components and signaling pathways continues to elaborate the complexity of this system. Regulation of RAS according to the conventional and contemporary views of its functions in various tissues under pathophysiological conditions is a main treatment strategy for many metabolic diseases. The local pancreatic RAS, first proposed to exist in pancreatic islets two decades ago, could regulate islet function and glycemic control via influences on islet cell mass, inflammation, and ion channels. Insulin secretion, the major function of pancreatic islets, is controlled by numerous factors. Among these factors and of particular interest are glucagon-like peptide-1 (GLP-1) and vitamin D, which may regulate islet function by directly binding receptors on islet beta cells. These factors may work with local RAS signaling in islets to protect and maintain islet function under diabetic and hyperglycemic conditions. In this concise review, the local islet RAS will be discussed with particular attention being paid to recent notable findings.

Prevention and current onset delay approaches of type 2 diabetes mellitus (T2DM)

The urgent need to treat type 2 diabetes mellitus (T2DM), which is currently reaching epidemic proportions, has been a major focus of healthcare systems and policy makers worldwide. Pharmacological treatment and lifestyle interventions together with the control of cardiovascular risk factors are the main strategies to prevent or delay the onset of T2DM. The present review discusses the state of the art knowledge of effective therapeutic approaches (metformin, thiazolidinediones, nateglinides, α-glucosidase inhibitors, incretin-based and angiotensin-based therapies, weight reducers, statins, fibric acid derivatives), including surgery, and identifies the major lifestyle changes for specific target groups.

Drug-induced hypoglycaemia: an update

Drugs are the most frequent cause of hypoglycaemia in adults. Although hypoglycaemia is a well known adverse effect of antidiabetic agents, it may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including NSAIDs, analgesics, antibacterials, antimalarials, antiarrhythmics, antidepressants and other miscellaneous agents. They induce hypoglycaemia by stimulating insulin release, reducing insulin clearance or interfering with glucose metabolism. Several drugs may also potentiate the hypoglycaemic effect of antidiabetic agents. Administration of these agents to individuals with diabetes mellitus is of most concern. Many of these drugs, and depending on clinical setting, may also induce hyperglycaemia. Drug-induced hepatotoxicity and nephrotoxicity may lead in certain circumstances to hypoglycaemia. Some drugs may also induce hypoglycaemia by causing pancreatitis. Drug-induced hypoglycaemia is usually mild but may be severe. Effective clinical management can be handled through awareness of this drug-induced adverse effect on blood glucose levels. Herein, we review pertinent clinical information on the incidence of drug-induced hypoglycaemia and discuss the underlying pathophysiological mechanisms, and prevention and management.

Prevention of metabolic syndrome in serious mental illness

The interaction of lifestyle, socioeconomic status, genetic factors, and treatment with antipsychotic medications likely accounts for the high risk of metabolic syndrome, diabetes, heart disease, and premature mortality in people with serious mental illness. Given the high risk of developing diabetes and cardiovascular disease in persons with serious mental illness, psychiatrists who treat these individuals need to ensure they are familiar with these risks, monitor metabolic parameters in their patients, and educate their patients (and caregivers) about the risks and how to prevent them.

High dose astaxanthin lowers blood pressure and increases insulin sensitivity in rats: are these effects interdependent?

The present investigation in Sprague-Dawley rats (SD) was designed to examine effects of astaxanthin (Asta) at different doses on elevated blood pressure (BP) and glucose-insulin perturbations produced by heavy sucrose ingestion. We also examined effects of Asta on BP during restraint stress. SD were divided into six groups each containing eight rats. All SD ate a basic diet of ground regular rat chow with sucrose added at 30% w/w. The Control group received only the basic diet containing added sucrose, while the other five groups each received the same diet with added test material: captopril, (30 mg/Kg), pioglitazone (15.0 mg/Kg), low Asta (25 mg/Kg), medium Asta (50 mg/kg) or high Asta (100 mg/Kg). Many tests were carried out to examine the mechanisms behind the effects of Asta on BP (serum ACE activity, losartan challenge, and LNAME challenge) and the glucose-insulin system (glucose tolerance, HOMA measurement, and insulin challenge). In SD, a relatively low dose of Asta decreased SBP, but produced no major changes in the glucose-insulin system simulating results from a previous study using Zucker Fatty Rats. Increasing the dose of Asta resulted in both a lowering of elevated systolic BP and enhanced insulin sensitivity determined by many different estimations. BP lowering was consistent with changes in the renin-angiotensin (RAS) and nitric oxide (NO) systems. At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glucose-insulin metabolism while showing essentially no effects on BP. Accordingly, Asta beneficially affects both sucrose-induced elevations of BP and insulin resistance at relatively high doses in SD. Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glucose-insulin systems respectively.

Update on the prevention of type 2 diabetes

Diabetes has emerged as the modern day epidemic that is currently affecting over 220 million people worldwide and claiming at least 1.1 million lives in 2005 alone. The rise in diabetes is largely attributed to the epidemic of obesity together with sedentary lifestyle as well as unhealthy dietary habits. Despite evidence that glycemic control as well as control of other cardiovascular disease (CVD) risk factors such as hypertension and dyslipidemia decreases morbidity and mortality in the diabetic population, control of glycemia and other CVD risk factors remains largely suboptimal making the concept of prevention of diabetes very appealing to control CVD risk, especially that such a risk is already increased in people in the prediabetic stage. Several large controlled trials have been completed testing various options for diabetes prevention. In this paper we present an update on prevention of type 2 diabetes highlighting the major recent trials completed to date in this very important area of investigation.

Angiotensin inhibition and longevity: a question of hydration

With the advancement of medical and investigative science, it is somewhat surprising that although it is possible to stabilise medical patients with hypertension and the associated kidney dysfunction, obesity, diabetes and even cancer, there is still no clear method of significantly reducing these chronic disease pathologies, and thus, extending life expectancy. There is one hormone common to these pathologies, the antagonism of which goes some way to clinical improvements, and this is angiotensin, which is released during hypovolaemia. Angiotensin antagonists are used to treat many of these pathologies, and it has been shown in the obesity literature that angiotensin antagonists decrease weight, but also increase the drinking of water. Increased cellular hydration, and hence, improved mitochondrial metabolism could be one of the mechanisms for the reduction in weight seen in these studies, as well as for reducing the other pathologies, all showing metabolic dysfunction. It appears that the application of straightforward physiological regulation might be an appropriate medical approach to the prevention of hypertension, kidney disease, obesity, diabetes and cancer, and thus, to an increased life expectancy.

Obesity-related hypertension: epidemiology, pathophysiology, and clinical management

The prevalence of obesity, including childhood obesity, is increasing worldwide. Weight gain is associated with increases in arterial pressure, and it has been estimated that 60-70% of hypertension in adults is attributable to adiposity. Centrally located body fat, associated with insulin resistance and dyslipidemia, is a more potent determinant of blood pressure elevation than peripheral body fat. Obesity-related hypertension may be a distinct hypertensive phenotype with distinct genetic determinants. Mechanisms of obesity-related hypertension include insulin resistance, sodium retention, increased sympathetic nervous system activity, activation of renin-angiotensin-aldosterone, and altered vascular function. In overweight individuals, weight loss results in a reduction of blood pressure, however, this effect may be attenuated in the long term. An increasing number of community-based programs (including school programs and worksite programs) are being developed for the prevention and treatment of obesity. Assessment and treatment of the obese hypertensive patient should address overall cardiovascular disease (CVD) risk. There are no compelling clinical trial data to indicate that any one class of antihypertensive agents is superior to others, and in general the principles of pharmacotherapy for obese hypertensive patients are not different from nonobese patients. Future research directions might include: (i) development of effective, culturally sensitive strategies for the prevention and treatment of obesity; (ii) clinical trials to identify the most effective drug therapies for reducing CVD in obese, hypertensive patients; (iii) continued search for the genetic determinants of the obese, hypertensive phenotype.

Effect of telmisartan on selected adipokines, insulin sensitivity, and substrate utilization during insulin-stimulated conditions in patients with metabolic syndrome and impaired fasting glucose

Objective

Telmisartan improves glucose and lipid metabolism in rodents. This study evaluated the effect of telmisartan on insulin sensitivity, substrate utilization, selected plasma adipokines and their expressions in subcutaneous adipose tissue (SAT) in metabolic syndrome.

Design and methods

Twelve patients with impaired fasting glucose completed the double-blind, randomized, crossover trial. Patients received telmisartan (160 mg/day) or placebo for 3 weeks and vice versa with a 2-week washout period. At the end of each period, a hyperinsulinemic euglycemic clamp (HEC) combined with indirect calorimetry was performed. During HEC (0, 30, and 120 min), plasma levels of adipokines were measured and a needle biopsy (0 and 30 min) of SAT was performed.

Results

Fasting plasma glucose was lower after telmisartan compared with placebo (P<0.05). There were no differences in insulin sensitivity and substrate utilization. We found no differences in basal plasma adiponectin, resistin and tumour necrosis factor α (TNFα), but an increase was found in basal leptin, after telmisartan treatment. Insulin-stimulated plasma adiponectin (P<0.05), leptin and resistin (P<0.001) were increased, whereas TNFα was decreased (P<0.05) after telmisartan treatment. Expression of resistin, but not adiponectin, TNFα and leptin was increased after telmisartan treatment.

Conclusions

Despite the decrease in fasting plasma glucose, telmisartan does not improve insulin sensitivity and substrate utilization. Telmisartan increases plasma leptin as well as insulin-stimulated plasma adiponectin, leptin and resistin, and decreases plasma TNFα during HEC. Changes in plasma adipokines cannot be explained by their expressions in SAT. The changes in plasma adipokines might be involved in the metabolic effects of telmisartan in metabolic syndrome.

Effect of high-dose valsartan on inflammatory and lipid parameters in patients with Type 2 diabetes and hypertension

AIMS

The present study aimed to explore the impact of the angiotensin type 1 receptor blocker valsartan (VAL) on inflammatory-/lipid-/glucose parameters in hypertensive diabetic patients with and without coronary artery disease (CAD).

METHODS

This was a 16-week, randomized, double-blind, placebo-controlled two-center study with VAL 320 mg/d in 109 hypertensive diabetic patients (n=56 non-CAD; n=53 CAD).

RESULTS

VAL treatment did not significantly affect serum interleukin-6 (IL-6) or tumor necrosis factor alpha (TNFalpha) levels in the overall study population but significantly reduced serum IL-6 in the subgroup with high inflammatory load at baseline (IL-6>median (2.0 ng/L), n=54: [median, ng/L]): VAL: from 3.5 to 2.4; placebo: from 3.2 to 3.5; p=0.035). VAL significantly lowered total- and LDL-cholesterol in the whole study population: [median, mg/dL]: total cholesterol: VAL: from 178 to 168; placebo: from 174 to 173, p=0.039; LDL-cholesterol: VAL: from 96 to 90, placebo: from 102 to 103, p=0.006, whereas glycemic parameters were not affected.

CONCLUSIONS

The present study demonstrates significant anti-inflammatory efficacy of VAL in hypertensive diabetic patients with enhanced inflammatory burden. High-dose VAL therapy significantly lowered total- and LDL-cholesterol levels. The combined actions of cholesterol and blood pressure lowering by VAL may provide additional clinical benefits for these high-risk patients.

Review: Therapeutic potential of plasminogen activator inhibitor-1 inhibitors

Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of fibrinolysis and regulates cell migration and fibrosis. Preclinical studies using genetically altered mice and biological or small molecule inhibitors have elucidated a role for PAI-1 in the pathogenesis of thrombosis, vascular remodeling, renal injury, and initiation of diabetes. Inhibition of PAI-1 is a potential therapeutic strategy in these diseases.

Review: angiotensin II type 1 receptor blockers: class effects versus molecular effects

Highly selective angiotensin II (Ang II) type 1 (AT(1)) receptor blockers (ARBs) are now available. The AT(1) receptor is a member of the G protein-coupled receptor (GPCR) superfamily and block the diverse effects of Ang II. Several ARBs are available for clinical use. Most ARBs have common molecular structures (biphenyl-tetrazol and imidazole groups) and it is clear that ARBs have 'class effects'. On the other hand, recent clinical studies have demonstrated that not all ARBs have the same effects, and some benefits conferred by ARBs may not be class effects, and instead may be 'molecular effects'. In addition, each ARB has been clearly shown to have specific molecular effects in basic experimental studies, and these effects may be due to small differences in the molecular structure of each ARB. However, it is controversial whether ARBs have molecular effects in a clinical setting. Although the presence of molecular effects for each ARB based on experimental studies may not directly influence the clinical outcome, this possibility has not been adequately evaluated. This review focuses on the class effects versus molecular effects of ARBs from bench to bedside.

Tissue-specific effects of valsartan on rstn and fiaf gene expression in the ob/ob mouse

The RAS is a novel target in the study of diabetes, and clinical trials have indicated that ARBs, such as valsartan, may exert some of their clinical effects through an influence on adipose tissue. We studied the effect of valsartan on adipokine genes resistin (rstn) and fasting-induced adipose factor (fiaf) using obese and diabetic ob/ob mice. In addition to visceral and subcutaneous fat, rstn and fiaf mRNA levels were also measured in several other tissues known to express these adipokines, including the pituitary, cerebral cortex and hypothalamus. The significant findings were that (a) fiaf gene expression was elevated two- to fourfold in visceral and subcutaneous fat from ob/ob mice, compared with lean controls; (b) the increase in fiaf mRNA in subcutaneous, but not visceral, fat from ob/ob mice was returned to lean control levels following 2 weeks of valsartan treatment; (c) fiaf expression was reduced in the hypothalamus, but not in the cortex or pituitary, of ob/ob mice; (d) rstn expression was greatly reduced in visceral fat from ob/ob mice, compared with lean controls, but this was unaffected by valsartan; and (e) rstn expression was unchanged in all other tissues from ob/ob mice, with or without valsartan treatment.

Comparison of continuous positive airway pressure and valsartan in hypertensive patients with sleep apnea

RATIONALE

Randomized controlled trials (RCTs) have shown that continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea (OSA) reduces blood pressure (BP). CPAP treatment has never been compared with antihypertensive medications in an RCT.

OBJECTIVES

To assess the respective efficacy of CPAP and valsartan in reducing BP in hypertensive patients with OSA never treated for either condition.

METHODS

In this 8-week randomized controlled crossover trial, 23 hypertensive patients (office systolic BP/diastolic BP: 155 ± 14/102 ± 11 mm Hg) with OSA (age, 57 ± 8 yr; body mass index, 28 ± 5 kg/m(2); apnea-hypopnea index, 29 ± 18/h) were randomized first to either CPAP or valsartan (160 mg). The second 8-week period consisted of the alternative treatment (crossover) after a 4-week washout period.

MEASUREMENTS AND MAIN RESULTS

Office BP and 24-hour BP were measured before and at the end of the two active treatment periods. Twenty-four-hour mean BP was the primary outcome variable. There was an overall significant difference in 24-hour mean BP between treatments: the change in 24-hour mean BP was -2.1 ± 4.9 mm Hg (P < 0.01) with CPAP, and -9.1 ± 7.2 mm Hg with valsartan (P < 0.001), with a difference of -7.0 mm Hg (95% confidence interval, -10.9 to -3.1 mm Hg; P < 0.001). The difference was significant not only during daytime but also during nighttime: the change in nighttime mean BP with CPAP was -1.3 ± 4.6 mm Hg (not significant), and -7.4 ± 8.4 mm Hg with valsartan (P < 0.001), with a difference of -6.1 mm Hg (P < 0.05) (95% confidence interval, -10.8 to -1.4 mm Hg).

CONCLUSIONS

In an RCT, although the BP decrease was significant with CPAP treatment, valsartan induced a fourfold higher decrease in mean 24-hour BP than CPAP in untreated hypertensive patients with OSA. Clinical trial registered with www.clinicaltrials.gov (NCT00409487).

Angiotensin II type 1 and type 2 receptors regulate basal skeletal muscle microvascular volume and glucose use

Angiotensin II causes vasoconstriction via the type 1 receptor (AT(1)R) and vasodilatation through the type 2 receptor (AT(2)R). Both are expressed in muscle microvasculature, where substrate exchanges occur. Whether they modulate basal muscle microvascular perfusion and substrate metabolism is not known. We measured microvascular blood volume (MBV), a measure of microvascular surface area and perfusion, in rats during systemic infusion of angiotensin II at either 1 or 100 ng/kg per minute. Each caused a significant increase in muscle MBV. Likewise, administration of the AT(1)R blocker losartan increased muscle MBV by >3-fold (P<0.001). Hindleg glucose extraction and muscle interstitial oxygen saturation simultaneously increased by 2- to 3-fold. By contrast, infusing AT(2)R antagonist PD123319 significantly decreased muscle MBV by >or=80% (P<0.001). This was associated with a significant decrease in hindleg glucose extraction and muscle oxygen saturation. AT(2)R antagonism and inhibition of NO synthase each blocked the losartan-induced increase in muscle MBV and glucose uptake. In conclusion, angiotensin II acts on both AT(1)R and AT(2)R to regulate basal muscle microvascular perfusion. Basal AT(1)R tone restricts muscle MBV and glucose extraction, whereas basal AT(2)R activity increases muscle MBV and glucose uptake. Pharmacological manipulation of the balance of AT(1)R and AT(2)R activity affords the potential to improve glucose metabolism.

Angiotensin II exerts glucose-dependent effects on Kv currents in mouse pancreatic beta-cells via angiotensin II type 2 receptors

Hyperglycemia-associated glucotoxicity induces beta-cell apoptosis but the underlying mechanisms are unknown. Interestingly, prolonged exposure to high glucose upregulates the expression and function of the renin-angiotensin system (RAS). We hypothesize that the voltage-gated outward potassium (K(v)) current, which governs beta-cell membrane potential and insulin secretion, has a role in glucotoxicity. In this study, we investigated the effects of prolonged exposure to high glucose on mouse pancreatic beta-cells and concurrent effects on the RAS by examining changes in expression of angiotensin II (ANG II) receptors and changes in the expression and activity of K(v) channels. beta-Cells were incubated in high glucose medium for 1-7 days and then were examined with electrophysiological and molecular biology techniques. Prolonged exposure to high glucose produced a marked increase in beta-cell primary K(v) channel subunit, K(v)2.1, expression and K(v) current amplitude. Enhanced expression of ANG II type 1 receptor (AT(1)R) was also observed under high glucose conditions, whereas blockade of AT(1)R by losartan did not alter K(v) channel expression. External application of ANG II reduced K(v) current amplitude under normal, but not high, glucose conditions. The effect of ANG II on K(v) channel gating was abolished by ANG II type 2 receptor (AT(2)R) antagonism. These data suggest that hyperglycemia alters beta-cell function through modification of the K(v) channel which may be associated with the RAS.

Glucose and non-glucose predictors of future onset of type 2 diabetes in newly diagnosed essential hypertensives

BACKGROUND

Baseline fasting plasma glucose (FPG) level predicts the onset of type 2 diabetes mellitus (DM). Other predictors have been less investigated. This study aimed to investigate non-glucose predictors together with FPG for future onset of type 2 DM in fresh essential hypertensives.

METHODS

Consecutive nondiabetic patients with newly diagnosed essential hypertension were prospectively evaluated for diurnal blood pressure (BP) change by ambulatory BP monitoring, vascular endothelial function by plethysmography, and biomarkers by blood biochemistry. They were then given guideline-based treatment and followed-up regularly for more than 5 years.

RESULTS

During a mean follow-up period of 5.9 years, 6 of the 106 study patients developed DM. Baseline FPG, alanine aminotransferase (ALT) level, and day-night difference in diastolic BP were related to future onset of DM. FPG > 5.8 mmol/L (p = 0.034) and ALT > 31 U/L (p = 0.048) independently and day-night difference in diastolic BP < or = 2.9% potentially predicted new-onset DM (p = 0.089). Simultaneously having at least 2 of the indicators mentioned above at baseline is predictive of new-onset DM. Parameters of reactive hyperemia by plethysmography were not relevant.

CONCLUSION

In addition to FPG, baseline serum ALT level independently and diurnal diastolic BP changes potentially predicted future onset of type 2 DM in newly diagnosed hypertensives. Both glucose and non-glucose indicators could be examined together for early risk stratification of future DM.

Candesartan: widening indications for this angiotensin II receptor blocker?

Candesartan cilexetil is one of a number of drugs of the angiotensin II receptor blocker (ARB) class. Their principal mode of action involves competitive blockade of the angiotensin II type 1 receptor, thereby modulating the activity of the rennin-angiotensin-aldosterone system. Angiotensin II receptor blocker therapy has been proven to be well tolerated and effective in the management of hypertension, chronic heart failure with left ventricular dysfunction and the prevention and progression of diabetic renal disease. Candesartan is a highly potent, long-acting and selective angiotensin II type 1 receptor blocker. It was launched in 1998 for the treatment of hypertension. Its use has increased dramatically, with recently published data suggesting benefit in the treatment of stroke, heart failure, diabetic renal disease and most recently in preventing the development of or delaying the progression of diabetic retinopathy. In this article we review the literature on the use of ARB drugs in general before focusing on candesartan.

Phosphodiesterase 5 inhibition improves beta-cell function in metabolic syndrome

OBJECTIVE

This study tested the hypothesis that phosphodiesterase 5 inhibition alone or in combination with ACE inhibition improves glucose homeostasis and fibrinolysis in individuals with metabolic syndrome.

RESEARCH DESIGN AND METHODS

Insulin sensitivity, beta-cell function, and fibrinolytic parameters were measured in 18 adults with metabolic syndrome on 4 separate days after a randomized, crossover, double-blind, 3-week treatment with placebo, ramipril (10 mg/day), tadalafil (10 mg o.d.), and ramipril plus tadalafil.

RESULTS

Ramipril decreased systolic and diastolic blood pressure, ACE activity, and angiotensin II and increased plasma renin activity. Ramipril did not affect insulin sensitivity or beta-cell function. In contrast, tadalafil improved beta-cell function (P = 0.01). This effect was observed in women (331.9 +/- 209.3 vs. 154.4 +/- 48.0 32 micro x mmol(-1) x l(-1), respectively, for tadalafil treatment vs. placebo; P = 0.01) but not in men. There was no effect of any treatment on fibrinolysis. CONCLUSIONS Phosphodiesterase 5 inhibition may represent a novel strategy for improving beta-cell function in metabolic syndrome.

Chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels in ovariectomized rats

Approximately 50% of hypertensive patients are postmenopausal women; therefore, any antihypertensive therapy must not adversely affect bone loss in this population. Recently, however, concern has been raised that use of angiotensin AT1 receptor antagonists may increase the tendency to develop postmenopausal osteoporosis by decreasing transforming growth factor-beta1 (TGF-beta1), which has been implicated in bone mass maintenance. In the present study, we selected telmisartan and valsartan as representatives of angiotensin AT1 receptor antagonists and used ovariectomized (OVX) rats as a model of human postmenopausal osteoporosis. After 3 months treatment with telmisartan (5 mg/kg daily) or valsartan (10 mg/kg daily), OVX rats showed no signs of adverse effects on bone mineral density of the lumbar vertebrae (L1-L5) or the total femur, nor did treatment affect serum levels of osteocalcin and osteoclast-derived tartrate-resistant acid phosphatase (TRACP-5b). Bone TGF-beta1 content remained unchanged, although treatment with telmisartan and valsartan significantly reduced serum TGF-beta1 levels (p < 0.05). In conclusion, chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels and did not accelerate ovariectomy-induced bone loss in rats.

A selective peroxisome proliferator-activated receptor-gamma modulator, telmisartan, binds to the receptor in a different fashion from thiazolidinediones

Angiotensin type 1 receptor blockers are widely used for the treatment of hypertension, and one angiotensin type 1 receptor blocker, telmisartan, specifically activates the peroxisome proliferator-activated receptor (PPAR)-gamma. We studied the impact of PPARgamma mutants on transcriptional control and interaction with cofactors to elucidate differences in the molecular mechanism between telmisartan and other PPARgamma agonists, thiazolidinediones (TZDs). We created several amino acid substitutions in the ligand binding domain of PPARgamma that, based on molecular modeling, may affect the binding of these agents. In transient expression experiments, wild-type PPARgamma-mediated transcription stimulated by telmisartan was more than one third of that stimulated by TZDs. The activation stimulated by TZDs was impaired, whereas activation stimulated by telmisartan was retained, in the H323Y, S342A, and H449A mutants. In the Y473A mutant, the TZD-induced activation was further impaired and lower than that of telmisartan-induced activation. Coexpression of coactivators enhanced the activation by both telmisartan and TZDs, but activation by telmisartan always exceeded that of TZDs in the Y473A mutant. Based on a mammalian two-hybrid assay, the interaction with corepressors was retained in Y473A. Telmisartan and TZDs, but not 9cis retinoic acid, dissociated corepressors from the wild-type PPARgamma. Telmisartan most effectively dissociated corepressors from Y473A. The interaction with coactivators was enhanced by TZD activation of wild-type PPARgamma and both telmisartan and TZD activation of Y473A. Thus, the Y473A mutant is selectively stimulated by telmisartan but not TZDs, suggesting that telmisartan and TZDs have differential effects on the transcriptional control. In conclusion, these PPARgamma mutants could be powerful tools for developing novel therapeutic agents that retain the metabolic efficacy of PPARgamma activation with fewer adverse effects, such as the increase in body weight associated with TZDs.

On target to dual block RAS?

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are thought to possess cardioprotective, cerebroprotective, and nephroprotective properties. Both classes of agents can prevent or reverse endothelial dysfunction and atherosclerosis, thereby potentially reducing the risk of cardiovascular events. Such a reduction has been shown with angiotensin-converting enzyme inhibitors in patients with coronary artery disease, but no such data are scarce with angiotensin receptor blockers (Valsartan in Acute Myocardial Infarction study). Both angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have been shown to reduce damage in target organs, such as the heart and kidney, and to decrease cardiovascular mortality and morbidity in patients with congestive heart failure. These drugs (especially angiotensin receptor blockers) may successfully prevent atrial fibrillation and play a protective role in metabolic syndrome. In some clinical settings, combined therapy angiotensin-converting enzyme inhibitors with angiotensin receptor blocker (double blockade of the renin-angiotensin- aldosterone system) may appear the most effective.

Inhibiting angiotensin type 1 receptors as a target for diabetes

BACKGROUND

Angiotensin type 1 (AT1) receptor blockers (ARBs) are used to treat hypertension and related end-organ damage. ARBs have been recognised as regulators of glucose- and lipid metabolism. Clinical trials demonstrated that AT1 receptor antagonism lowers the risk for type 2 diabetes compared with other antihypertensive therapies. Blockade of AT1 receptors reduces cardiovascular morbidity and mortality in diabetic subpopulations. The mechanisms of the insulin-sensitizing/anti-diabetic effect are not fully understood, and may involve AT1 receptor-dependent pathways and 'pleiotropic' actions of ARBs including activation of insulin-sensitising PPARgamma.

OBJECTIVE

In clinical practice questions about AT1 receptor blockade in diabetes have to be answered. Firstly, is selective AT1-receptor blockade superior to ACE inhibition in preventing diabetes and reducing cardiovascular end points in diabetic patients? Secondly, is an ARB with PPARgamma-activating properties superior to one without this action?

RESULTS/CONCLUSION

The Ongoing Telmisartan Alone and in Combination with Ramipril Global End point Trial (ONTARGET) has provided information to answer these questions, and is discussed.