Telmisartan improves insulin resistance in high renin nonmodulating salt-sensitive hypertensives. J Hypertens. 2008;26:2393-2398. [PMID: 19008718 DOI: 10.1097/hjh.0b013e328312677e]

Angiotensin-converting enzyme inhibitors versus angiotensin II receptor blockers on insulin sensitivity in hypertensive patients: A meta-analysis of randomized controlled trials

Introduction

This meta-analysis aimed to summarize the available evidence to compare angiotensin-converting enzyme (ACE) inhibitors with angiotensin II receptor blockers (ARBs) on improving insulin sensitivity in hypertensive patients.

Methods

Randomized controlled trials (RCTs) comparing ACE inhibitors versus ARBs published with outcomes on homeostasis model assessment of IR (HOMA-IR), glucose infusion rate (GIR), the quantitative insulin sensitivity check index (QUICKI), insulin sensitivity index (ISI) composite, fasting plasma glucose (FPG), fasting plasma insulin (FPI), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were searched through 5 databases. Data were searched from their inception to July 5, 2020. Stata 14.0 was used to perform the meta-analysis.

Results

Eleven RCTs (n = 1015) were included in this meta-analysis. Pooled analysis of studies showed no significant difference in HOMA-IR between ARBs and ACE inhibitors (WMD = -0.09, 95% CI: -0.69 to 0.50, P = 0.755); however, subgroup analysis of therapeutic duration showed a significant difference in HOMA-IR between ARBs and ACE inhibitors among the long-term intervention subgroup (>12 weeks) (WMD = 0.41, 95% CI: 0.06 to 0.76, P = 0.022) and hypertensive patients with diabetes mellitus subgroup (WMD = 0.55, 95% CI: 0.49 to 0.61, P < 0.001); results showed no significant difference between ARBs and ACE inhibitors on QUICKI score (WMD = -0.00, 95% CI: -0.03 to 0.03, P = 0.953) in hypertensive patients; however, the efficacy of ACE inhibitors on improving GIR and ISI composite was significantly better than that of ARBs (WMD = -1.09, 95% CI: -1.34 to -0.85, P < 0.001; WMD = -0.80, 95% CI: -1.24 to -0.36, P < 0.001, respectively). Furthermore, no significant differences were noted on FPG (WMD = 0.72, 95% CI: -1.39 to 2.83, P = 0.505), FPI (WMD = -0.48, 95% CI: -1.60 to 0.64, P = 0.398), SBP (WMD = -0.65, 95% CI: -1.76 to 0.46, P = 0.254), and DBP (WMD = -0.30, 95% CI: -1.70 to 1.10, P = 0.675) between ARBs and ACE inhibitors.

Conclusion

Results from this meta-analysis showed that ACE inhibitors resulted in more effective improvement of HOMA-IR compared with ARBs among the long-term intervention and hypertensive patients with DM subgroup; furthermore, the efficacy of ACE inhibitors on improving GIR and ISI composite was significantly better than that of ARBs in hypertensive patients. However, ARBs had no significant difference in QUICKI score, FPG, FPI, SBP, and DBP compared with ACE inhibitors. Larger and better-designed studies are needed to further verify this conclusion.

Comparative Efficacy of Antihypertensive Agents in Salt-Sensitive Hypertensive Patients: A Network Meta-Analysis

BACKGROUND

Salt-sensitive hypertension (SSH) is an intermediate inherited phenotype of essential hypertension as well as being an independent risk factor for cardiovascular disease. However, effective medications for the treatment of SSH have not been clarified. This study was to compare the efficacious of different classes of antihypertensive agents combined with salt intake on the reduction of blood pressure (BP) in patients with SSH.

METHODS

We used sources as PubMed, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), CNKI, and WANFANG database from inception to November 2016. Studies that compared the efficacy of 2 or more antihypertensive agents or placebos in adult salt-sensitive hypertensive patients were included. The outcomes included variations in mean arterial blood pressure, systolic and diastolic blood pressure.

RESULTS

Twenty-five studies were involved in this meta-analysis. A calcium channel blocker (CCB) with hydrochlorothiazide and moderate salt intake was significantly the most efficacious in comparison with placebo (standardized mean differences (SMD), 95% credibility intervals (CI): 26.66, 12.60 to 40.16), angiotensin receptor blockers (ARBs) (SMD, 95% CI: 22.94, 5.26 to 40.51), and the other interventions for patients with SSH and no concomitant diseases. For SSH patients who were obese, CCB with metformin and moderate salt intake would decrease blood pressure with 17.90 mm Hg.

CONCLUSIONS

For SSH patients with no concomitant diseases, CCB combined with hydrochlorothiazide and moderate salt intake was optimal in reducing BP, while CCB combined with metformin and moderate salt intake was the most efficacious at reducing BP in SSH patients with coexisting obesity.

Interplay between the renin-angiotensin system, the canonical WNT/β-catenin pathway and PPARγ in hypertension

PURPOSE OF REVIEW

Heterogeneous causes can determinate hypertension.

RECENT FINDINGS

The renin-angiotensin system (RAS) has a major role in the pathophysiology of blood pressure. Angiotensin II and aldosterone are overexpressed during hypertension and lead to hypertension development and its cardiovascular complications. In several tissues, the overactivation of the canonical WNT/β-catenin pathway leads to inactivation of peroxisome proliferator-activated receptor gamma (PPARγ), while PPARγ stimulation induces a decrease of the canonical WNT/β-catenin pathway. In hypertension, the WNT/β-catenin pathway is upregulated, whereas PPARγ is decreased. The WNT/β-catenin pathway and RAS regulate positively each other during hypertension, whereas PPARγ agonists can decrease the expression of both the WNT/β-catenin pathway and RAS. We focus this review on the hypothesis of an opposite interplay between PPARγ and both the canonical WNT/β-catenin pathway and RAS in regulating the molecular mechanism underlying hypertension. The interactions between PPARγ and the canonical WNT/β-catenin pathway through the regulation of the renin-angiotensin system in hypertension may be an interesting way to better understand the actions and the effects of PPARγ agonists as antihypertensive drugs.

Telmisartan is effective to ameliorate metabolic syndrome in rat model - a preclinical report

BACKGROUND

Metabolic syndrome (MS) is known to be associated with hypertension, insulin resistance, and dyslipidemia, and it raises the risk for cardiovascular diseases and diabetes mellitus. Telmisartan is used in clinic as an angiotensin II receptor blocker and it is also identified as activating peroxisome proliferator-activated receptors δ (PPARδ). Activation of PPARδ produced beneficial effects on fatty acid metabolism and glucose metabolism. This study aims to investigate the effects of telmisartan on the modulation of MS in rats fed a high-fat/high-sodium diet.

METHODS

Rats were fed with a high-fat/high-sodium diet and received injections of streptozotocin at low dose to induce MS. Then, rats with MS were treated with telmisartan. The weight, glucose tolerance, and insulin sensitivity were measured. The lipid profiles were also obtained. The weights of retroperitoneal and epididymal fat pads were determined. The role of PPARδ in telmisartan treatment was identified in rats pretreated with the specific antagonist GSK0660.

RESULTS

The results showed that telmisartan, but not losartan, significantly reduced plasma glucose and plasma insulin, and improved insulin resistance in rats with MS. Telmisartan also decreased blood pressure and lipids more significantly than losartan. Moreover, GSK0660 effectively reversed the effects of telmisartan in the MS rats. In the MS group, telmisartan activated PPARδ to enhance the levels of phosphorylated GLUT4 in muscle or the expression of phosphoenolpyruvate carboxykinase (PEPCK) in the liver, which was also abolished by GSK0660. Telmisartan is useful to ameliorate hypertension and insulin resistance in rats with MS. Telmisartan improves the insulin resistance through increased expression of GLUT4 and down-regulation of PEPCK via PPARδ-dependent mechanisms.

CONCLUSION

Telmisartan has been proven to ameliorate MS, particularly in the prediabetes state. Therefore, telmisartan is suitable to develop for the management of MS in clinics.

The Role of PPARγ in Cardiovascular Diseases

The peroxisome proliferator-activated receptors (PPAR) belong to the nuclear superfamily of ligand-activated transcription factors. PPARγ acts as a nutrient sensor that regulates several homeostatic functions. Its disruption can lead to vascular pathologies, disorders of fatty acid/lipid metabolism and insulin resistance. PPARγ can modulate several signaling pathways connected with blood pressure regulation. Firstly, it affects the insulin signaling pathway and endothelial dysfunction by modulation of expression and/or phosphorylation of signaling molecules through the PI3K/Akt/eNOS or MAPK/ET-1 pathways. Secondly, it can modulate gene expression of the renin- angiotensin system – cascade proteins, which potentially slow down the progression of atherosclerosis and hypertension. Thirdly, it can modulate oxidative stress response either directly through PPAR or indirectly through Nrf2 activation. In this context, activation and functioning of PPARγ is very important in the regulation of several disorders such as diabetes mellitus, hypertension and/or metabolic syndrome.

Gastrodin Reduces Blood Pressure by Intervening with RAAS and PPARγ in SHRs

Gastrodin is a bioactive compound extracted from traditional Chinese medicine, Gastrodia elata  Bl. It has a definite effect on reducing blood pressure in hypertensive patients. However, the mechanisms of gastrodin in lowering blood pressure still remain unclear. In this study, 4 weeks of administration of gastrodin (100 mg/kg/d intraperitoneally injected) decreased the systolic blood pressure (SBP) in spontaneously hypertensive rats (SHRs) (190.2 ± 8.9 versus 169.8 ± 6.4, P < 0.01). Among SHRs receiving gastrodin treatment, angiotensin II (Ang II) and aldosterone (ALD) in serum were significantly decreased (2022.1 ± 53.0 versus 1528.7 ± 93.9, 213.33 ± 35.17 versus 179.65 ± 20.31, and P < 0.01, P < 0.05, resp.) and dramatically downregulated expression of angiotensin type 1 receptor (AT1R) (4.9 ± 0.9 versus 2.6 ± 0.9, P < 0.05) in myocardium in both mRNA and protein levels compared with their corresponding groups without gastrodin treatment. Additionally, gastrodin increased the mRNA expression (0.18 ± 0.07 versus 0.82 ± 0.10, P < 0.01) and protein synthesis (0.40 ± 0.10 versus 0.34 ± 0.10, P < 0.01) of peroxisome proliferator-activated receptor γ (PPARγ) in myocardium tissues. Overall, our data demonstrated that gastrodin was able to decrease the SBP in SHR. Furthermore, this study showed that gastrodin intervened with the renin-angiotensin-aldosterone system (RAAS) and PPARγ effectively, which indicates its antihypertensive mechanism.

Oxidative stress, insulin resistance, dyslipidemia and type 2 diabetes mellitus

Oxidative stress is increased in metabolic syndrome and type 2 diabetes mellitus (T2DM) and this appears to underlie the development of cardiovascular disease, T2DM and diabetic complications. Increased oxidative stress appears to be a deleterious factor leading to insulin resistance, dyslipidemia, β-cell dysfunction, impaired glucose tolerance and ultimately leading to T2DM. Chronic oxidative stress, hyperglycemia and dyslipidemia are particularly dangerous for β-cells from lowest levels of antioxidant, have high oxidative energy requirements, decrease the gene expression of key β-cell genes and induce cell death. If β-cell functioning is impaired, it results in an under production of insulin, impairs glucose stimulated insulin secretion, fasting hyperglycemia and eventually the development of T2DM.

A meta-analysis of randomized trials of telmisartan versus active controls for insulin resistance in hypertensive patients

To determine whether telmisartan improves insulin resistance compared with other antihypertensive drugs, we performed a meta-analysis of randomized controlled trials (RCTs) of telmisartan. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched through December 2013. Eligible studies were prospective RCTs of telmisartan versus other antihypertensive drugs, enrolling individuals with hypertension and reporting insulin levels and/or homeostasis model assessment-insulin resistance (HOMA-IR) as outcomes. Of 67 potentially relevant articles screened initially, 33 reports of RCTs enrolling a total of 2033 patients with hypertension were identified and included. Pooled analyses of only the eight double-blind-design trials demonstrated statistically significant reductions in percent changes of insulin levels (mean difference, -5.19%; 95% confidence interval, -8.94% to -1.43%; P = .007) and HOMA-IR (-15.34%; -26.39% to -4.28%; P = .007) with telmisartan relative to other antihypertensive drugs. When data from all the 33 trials were pooled, telmisartan was associated with statistically significant reductions in percent changes of insulin levels (-10.92%; -15.60% to -6.23%; P < .00001) and HOMA-IR (-15.89%; -22.01% to -9.78%; P < .00001) relative to other antihypertensive drugs. In conclusion, telmisartan appears to significantly improve insulin resistance compared with other antihypertensive drugs in patients with hypertension.

Hypertension in metabolic syndrome: vascular pathophysiology

METABOLIC SYNDROME IS A CLUSTER OF METABOLIC AND CARDIOVASCULAR SYMPTOMS: insulin resistance (IR), obesity, dyslipemia. Hypertension and vascular disorders are central to this syndrome. After a brief historical review, we discuss the role of sympathetic tone. Subsequently, we examine the link between endothelial dysfunction and IR. NO is involved in the insulin-elicited capillary vasodilatation. The insulin-signaling pathways causing NO release are different to the classical. There is a vasodilatory pathway with activation of NO synthase through Akt, and a vasoconstrictor pathway that involves the release of endothelin-1 via MAPK. IR is associated with an imbalance between both pathways in favour of the vasoconstrictor one. We also consider the link between hypertension and IR: the insulin hypothesis of hypertension. Next we discuss the importance of perivascular adipose tissue and the role of adipokines that possess vasoactive properties. Finally, animal models used in the study of vascular function of metabolic syndrome are reviewed. In particular, the Zucker fatty rat and the spontaneously hypertensive obese rat (SHROB). This one suffers macro- and microvascular malfunction due to a failure in the NO system and an abnormally high release of vasoconstrictor prostaglandins, all this alleviated with glitazones used for metabolic syndrome therapy.

Comparison of hyperkalemic risk in hospitalized patients treated with different angiotensin receptor blockers: a retrospective cohort study using a Korean clinical research database

BACKGROUND AND AIM

Clinical use of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) is associated with hyperkalemia as an adverse drug reaction. Although it has significant clinical implications, the incidence and relative risks of hyperkalemia with various ARBs have not yet been fully evaluated. The purpose of this study was to determine the risk of hyperkalemic events in hospitalized patients treated with different ARBs and to compare the risk among them.

METHODS

We constructed a retrospective cohort composed of hospitalized adult patients who took ARBs in a single tertiary teaching hospital between April 2004 and March 2010. We estimated the incidence of hyperkalemia (serum potassium level >5.5 mEq/L) with various ARBs, and then compared the risk between them using a multivariate Cox proportional hazard model based on age, sex, Charlson co-morbidity score, baseline serum potassium, underlying diseases, and concomitant drugs.

RESULTS

We identified 6992 evaluable intervals from 5449 patients treated with one of the seven ARBs during hospitalization over the 71-month study period with 2521.6 patient-months. We found 381 hyperkalemic events (5.4%) during the study period and an overall event rate of 15.1/100 patient-months. Moderate to fatal hyperkalemia was relatively rare (>6.0 mEq/L, 2.1% [moderate]; >6.5 mEq/L, 0.9% [severe]; >7.0 mEq/L, 0.3% [fatal]). After adjustment for covariates, telmisartan showed a lower risk of hyperkalemia (hazard ratio 0.67; 95% confidence interval 0.51, 0.89) compared with all other ARBs.

CONCLUSION

The risk of hyperkalemic events in hospitalized patients treated with different ARBs was defined. Telmisartan showed a relatively lower hyperkalemic risk profile in hospitalized patients compared with other ARBs.

Double blockade of angiotensin II (AT(1) )-receptors and ACE does not improve weight gain and glucose homeostasis better than single-drug treatments in obese rats

BACKGROUND AND PURPOSE

Combination therapies are becoming increasingly important for the treatment of high blood pressure. Little is known about whether double blockade of angiotensin II (AT(1) ) receptors and angiotensin-converting enzyme (ACE) exert synergistic metabolic effects.

EXPERIMENTAL APPROACH

Spontaneously hypertensive rats were allowed to choose between palatable chocolate bars and standard chow and were simultaneously treated with the AT(1) blocker telmisartan (8 mg·kg(bw) (-1) ·day(-1) ), the ACE inhibitor ramipril (4 mg·kg(bw) (-1) ·day(-1) ) or a combination of the two (8 + 4 mg·kg(bw) (-1) ·day(-1) ) for 12 weeks.

KEY RESULTS

Although food-dependent energy intake was increased by telmisartan and telmisartan + ramipril compared with ramipril or controls, body weight gain, abundance of fat and plasma leptin levels were decreased. Increased insulin levels in response to an oral glucose tolerance test were comparably attenuated by telmisartan and telmisartan + ramipril, but not by ramipril. During an insulin tolerance test, glucose utilization was equally as effectively improved by telmisartan and telmisartan + ramipril. In response to a stress test, ACTH, corticosterone and glucose increased in controls. These stress reactions were attenuated by telmisartan and telmisartan + ramipril.

CONCLUSIONS AND IMPLICATIONS

The combination of telmisartan + ramipril was no more efficacious in regulating body weight and glucose homeostasis than telmisartan alone. However, telmisartan was more effective than ramipril in improving metabolic parameters and in reducing body weight. The association between the decrease in stress responses and the diminished glucose levels after stress supports our hypothesis that the ability of telmisartan, as an AT(1) receptor blocker, to alleviate stress reactions may contribute to its hypoglycaemic actions.

Updated report on comparative effectiveness of ACE inhibitors, ARBs, and direct renin inhibitors for patients with essential hypertension: much more data, little new information

OBJECTIVES

A 2007 systematic review compared angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in patients with hypertension. Direct renin inhibitors (DRIs) have since been introduced, and significant new research has been published. We sought to update and expand the 2007 review.

DATA SOURCES

We searched MEDLINE and EMBASE (through December 2010) and selected other sources for relevant English-language trials.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included studies that directly compared ACE inhibitors, ARBs, and/or DRIs in at least 20 total adults with essential hypertension; had at least 12 weeks of follow-up; and reported at least one outcome of interest. Ninety-seven (97) studies (36 new since 2007) directly comparing ACE inhibitors versus ARBs and three studies directly comparing DRIs to ACE inhibitor inhibitors or ARBs were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

A standard protocol was used to extract data on study design, interventions, population characteristics, and outcomes; evaluate study quality; and summarize the evidence.

RESULTS

In spite of substantial new evidence, none of the conclusions from the 2007 review changed. The level of evidence remains high for equivalence between ACE inhibitors and ARBs for blood pressure lowering and use as single antihypertensive agents, as well as for superiority of ARBs for short-term adverse events (primarily cough). However, the new evidence was insufficient on long-term cardiovascular outcomes, quality of life, progression of renal disease, medication adherence or persistence, rates of angioedema, and differences in key patient subgroups.

LIMITATIONS

Included studies were limited by follow-up duration, protocol heterogeneity, and infrequent reporting on patient subgroups.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Evidence does not support a meaningful difference between ACE inhibitors and ARBs for any outcome except medication side effects. Few, if any, of the questions that were not answered in the 2007 report have been addressed by the 36 new studies. Future research in this area should consider areas of uncertainty and be prioritized accordingly.

Antihypertensive and metabolic effects of telmisartan in hypertensive HIV-positive patients

BACKGROUND

Hypertension is more prevalent among HIV-infected individuals than in the general population and contributes to increased cardiovascular risk. The angiotensin II receptor blocker telmisartan is also a partial peroxisome proliferator activated receptor-γ agonist with documented effects on glucose and lipid homeostasis. The aim of this study was to evaluate the antihypertensive and metabolic effects of telmisartan in hypertensive HIV-positive patients.

METHODS

A total of 18 HIV-positive men treated with antiretroviral therapy and recently diagnosed with hypertension were administered 80 mg telmisartan daily. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), viroimmunological and metabolic parameters, insulin resistance, C-reactive protein, microalbuminuria, cystatin C and plasma levels of interleukin-18 and endothelin-1 were measured at baseline (T0), 1 month (T1), 3 months (T3) and 6 months (T6).

RESULTS

Treatment with telmisartan not only decreased SBP and DBP levels, but also improved insulin resistance and microalbuminuria by T1. Levels of triglycerides significantly decreased and high-density lipoprotein cholesterol increased at T1, whereas total and low-density lipoprotein cholesterol levels were statistically reduced at T3 and T6. Cystatin C and endothelin-1 showed a significant reduction at T1, whereas interleukin-18 decreased at both T3 and T6.

CONCLUSIONS

Telmisartan was effective in reducing blood pressure and improving lipid metabolism and renal function. Reduction of endothelin-1 might be related to an endothelial protective effect. On the basis of these findings, and because of properties unrelated to blood pressure lowering, telmisartan might be the first choice antihypertensive drug for the treatment of HIV-positive patients.

Insulin resistance, inflammation, and vascular disease in nondiabetic predialysis chronic kidney disease patients

BACKGROUND

Chronic kidney disease (CKD) is associated with high cardiovascular morbidity and mortality, which is not fully explained by traditional risk factors; hence, the interest in nontraditional risk factors such as inflammation and insulin resistance (IR). Though IR is shown in nondiabetic CKD, its association with vascular disease and inflammation in this population is unknown, and is what this study aims to investigate.

HYPOTHESIS

IR and inflammation are related to vascular disease in nondiabetic predialysis CKD patients.

METHODS

We studied carotid-artery intima-media thickness (IMT) and endothelial function (brachial artery flow mediated dilation [FMD]) in 35 nondiabetic predialysis patients with stage 3-5 CKD and 35 age- and gender-matched controls. Insulin resistance was measured using the homeostasis model assessment for insulin resistance score (HOMA-IR), inflammation by high-sensitivity CRP (hsCRP), and their relationship with FMD and IMT.

RESULTS

Patients with CKD showed reduced FMD (3.34 ± 2.14% vs. 5.27 ± 1.78%, P<0.001) and increased IMT (0.78 ± 0.22 mm vs. 0.64 ± 0.16 mm, P = 0.003) compared with controls. The CKD patients had a higher HOMA-IR (2.20 ± 1.08 vs. 1.13 ± 0.64, P<0.001) and hsCRP (3.25 ± 5.47 mg/L vs. 1.10 ± 1.85 mg/L [median ± interquartile range], P = 0.02). In the study population, HOMA-IR was directly related to hsCRP. After adjusting for traditional risk factors, high HOMA-IR and hsCRP were significantly related to decreased FMD (adjusted β = -0.44, 95% confidence interval [CI]: -1.55 to -0.08, P = 0.003 and adjusted β = -0.51, 95% CI: -0.51 to -0.15, P = 0.001) and increased IMT (adjusted β = 0.62, 95% CI: 0.54-1.90, P = 0.001 and adjusted β = 0.43, 95% CI: 0.08-0.57, P = 0.011), respectively.

CONCLUSIONS

Subjects with systemic inflammation were more insulin-resistant, and in nondiabetic predialysis CKD, IR and systemic inflammation were independently associated with endothelial dysfunction and atherosclerosis.

Telmisartan improves morphologic and functional changes in both left ventricular myocardium and carotid arterial wall in patients with hypertension: assessment by tissue Doppler imaging and carotid ultrasonography

OBJECTIVE

The aim of the present study was to clarify the beneficial effects of telmisartan on the morphologic and functional changes in left ventricular (LV) myocardium and carotid arterial wall in patients with hypertension (HT) using tissue Doppler imaging and carotid ultrasonography.

METHODS

Telmisartan (20-40 mg daily) was administered to 35 previously untreated patients with HT. Conventional and pulsed tissue Doppler echocardiography were performed after medication had been continued for 1-2 months with normal values for blood pressure (BP) (phase I) and for 12 months (phase II). Subclinical atherosclerosis also was determined by measuring the intima-media thickness (IMT) and stiffness β of the left and right common carotid arteries using B- and M-mode ultrasonography.

RESULTS

In the phase II, the LV mass index and isovolumic relaxation time were lower, the peak systolic and early diastolic mitral annular motion velocities were greater compared to the phase I. The stiffness β and mean IMT were lower in the phase II than in the phase I. On multivariate regression analyses, age, BP, and LV diastolic variables emerged as stronger predictors of carotid arterial IMT and stiffness β.

CONCLUSIONS

The 1-year use of telmisartan improved LV hypertrophy, regional LV myocardial contraction and relaxation, and carotid atherosclerosis in patients with HT. Our results support cardio- and arterioprotective benefits from continuous long-term telmisartan monotherapy, and combined analysis of tissue Doppler imaging and carotid ultrasonography may be a useful tool for understanding ventriculoarterial coupling in patients with HT.

PPARs in the Renal Regulation of Systemic Blood Pressure

Recent research has revealed roles for the peroxisome proliferator activated receptor (PPAR) family of transcription factors in blood pressure regulation, expanding the possible therapeutic use of PPAR ligands. PPARalpha and PPARgamma modulate the renin-angiotensin-aldosterone system (RAAS), a major regulator of systemic blood pressure and interstitial fluid volume by transcriptional control of renin, angiotensinogen, angiotensin converting enzyme (ACE) and angiotensin II receptor 1 (AT-R1). Blockade of RAAS is an important therapeutic target in hypertension management and attenuates microvascular damage, glomerular inflammation and left ventricular hypertrophy in hypertensive patients and also show antidiabetic effects. The mechanisms underlying the benefits of RAAS inhibition appear to involve PPARgamma-regulated pathways. This review summarizes current knowledge on the role of PPARs in the transcriptional control of the RAAS and the possible use of PPAR ligands in the treatment of RAAS dependent hypertension.

Telmisartan: a different angiotensin II receptor blocker protecting a different population?

The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET()) showed that the angiotensin II receptor blocker (ARB) telmisartan was as protective as the reference-standard ramipril in a broad cross-section of patients at increased cardiovascular risk, but was better tolerated. Telmisartan has a unique profile among ARBs, with a high affinity for the angiotensin II type 1 receptor, a long duration of receptor binding, a high lipophilicity and a long plasma half life. This leads to sustained and powerful blood pressure lowering when compared with the first marketed ARBs, such as losartan and valsartan. Some pharmacological properties of telmisartan clearly distinguish it from other members of the ARB class and may contribute to the clinical effects seen with telmisartan. A class effect for ARBs cannot be assumed. To date, telmisartan is the only ARB that has been shown to reduce cardiovascular risk in at-risk cardiovascular patients.

Telmisartan prevents weight gain and obesity through activation of peroxisome proliferator-activated receptor-delta-dependent pathways

Telmisartan shows antihypertensive and several pleiotropic effects that interact with metabolic pathways. In the present study we tested the hypothesis that telmisartan prevents adipogenesis in vitro and weight gain in vivo through activation of peroxisome proliferator-activated receptor (PPAR)-delta-dependent pathways in several tissues. In vitro, telmisartan significantly upregulated PPAR-delta expression in 3T3-L1 preadipocytes in a time- and dose-dependent manner. Other than enhancing PPAR-delta expression by 68.2+/-17.3% and PPAR-delta activity by 102.0+/-9.0%, telmisartan also upregulated PPAR-gamma expression, whereas neither candesartan nor losartan affected PPAR-delta expression. In vivo, long-term administration of telmisartan significantly reduced visceral fat and prevented high-fat diet-induced obesity in wild-type mice and hypertensive rats but not in PPAR-delta knockout mice. Administration of telmisartan did not influence food intake in mice. Telmisartan influenced several lipolytic and energy uncoupling related proteins (UCPs) and enhanced phosphorylated protein kinase A and hormone sensitive lipase but reduced perilipin expression and finally inhibited adipogenesis in 3T3-L1 preadipocytes. Telmisartan-associated reduction of adipogenesis in preadipocytes was significantly blocked after PPAR-delta gene knockout. Chronic telmisartan treatment upregulated the expressions of protein kinase A, hormone-sensitive lipase, and uncoupling protein 1 but reduced perilipin expression in adipose tissue and increased uncoupling protein 2 and 3 expression in skeletal muscle in wild-type mice but not in PPAR-delta knockout mice. We conclude that telmisartan prevents adipogenesis and weight gain through activation of PPAR-delta-dependent lipolytic pathways and energy uncoupling in several tissues.

Metabolic syndrome and oxidative stress

Metabolic syndrome is an obesity-associated collection of disorders, each of which contributes to cardiovascular risk. Metabolic syndrome is also associated with overproduction of reactive oxygen species (ROS). ROS contribute to the interrelationship between metabolic syndrome and salt-sensitive hypertension, which are both caused by obesity and excess salt consumption and are major threats to health in developed countries. ROS can induce insulin resistance, which is indispensable for the progression of metabolic syndrome, and salt-sensitive hypertension stimulates ROS production, thereby promoting the development of metabolic syndrome. Moreover, ROS activate mineralocorticoid receptors (MRs) and the sympathetic nervous system, which can contribute to the development of metabolic syndrome and salt-sensitive hypertension. Salt-induced progression of cardiovascular disease (CVD) is also accelerated in animal models with metabolic syndrome, probably owing to further stimulation of ROS overproduction and subsequent ROS-induced MR activation and sympathetic excitation. Therefore, ROS contribute to the progression of the metabolic syndrome itself and to the CVD accompanying it, particularly in conjunction with excessive salt consumption.