Old antihypertensives and new diabetes

Visit-to-visit variability in triglyceride-glucose index and diabetes: A 9-year prospective study in the Kailuan Study

INSTRUCTION/AIMS

It is unknown whether variability in the triglyceride-glucose index (TyG-index) is associated with the risk of diabetes. Here, we sought to characterize the relationship between TyG-index variability and incident diabetes.

METHODS

We performed a prospective study of 48,013 participants in the Kailuan Study who did not have diabetes. The TyG-index was calculated as ln [triglyceride (TG, mg/dL) concentration × fasting blood glucose concentration (FBG, mg/dL)/2]. The TyG-index variability was assessed using the standard deviation (SD) of three TyG-index values that were calculated during 2006/07, 2008/09, and 2010/11. We used the Cox proportional hazard models to analyze the effect of TyG-index variability on incident diabetes.

RESULTS

A total of 4,055 participants were newly diagnosed with diabetes during the study period of 8.95 years (95% confidence interval (CI) 8.48-9.29 years). After adjustment for confounding factors, participants in the highest and second-highest quartiles had significantly higher risks of new-onset diabetes versus the lowest quartile, with hazard ratios (95% CIs) of 1.18 (1.08-1.29) and 1.13 (1.03-1.24), respectively (P trend< 0.05). These higher risks remained after further adjustment for the baseline TyG-index.

CONCLUSIONS

A substantial fluctuation in TyG-index is associated with a higher risk of diabetes in the Chinese population, implying that it is important to maintain a normal and consistent TyG-index.

Comparative risk of new-onset diabetes mellitus for antihypertensive drugs in elderly: A Bayesian network meta-analysis

There is no study to compare different class of antihypertensive drugs on new-onset diabetes mellitus (NOD) in elderly. We aimed to investigate the risk of antihypertensive drugs on NOD in elderly patients. The databases were retrieved in an orderly manner from the dates of their establishment to October, 2018, including Medline, Embase, Clinical Trials, and the Cochrane Database, to collect randomized controlled trials (RCTs) of different antihypertensive drugs in elderly patients (age > 60 years). Then, a network meta-analysis was conducted using R and Stata 12.0 softwares. A total of 14 RCTs involving 74 042 patients were included. The relative risk of NOD mellitus associated with six classes of antihypertensive drugs was analyzed, including placebo, angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), diuretics, and β blockers. Patients with ACEIs or ARBs appeared to have significantly reduced risk of NOD compare with placebo: ACEIs (OR = 0.49, 95% CrI 0.28-0.85), ARBs (OR = 0.37, 95% CrI 0.26-0.52), while CCBs, diuretics, and β blockers appeared to have not significantly reduced risk of NOD mellitus compare with placebo: CCBs (OR = 1.10, 95% CrI 0.85-1.60), diuretics (OR = 1.40, 95% CrI 0.92-2.50), β blockers (OR = 1.40, 95% CrI 0.93-2.10). The SUCRA of placebo, ACEIs, ARBs, CCBs, diuretics, and β blockers was, respectively, 65.3%, 69.3%, 92.3%, 44.1%, 12.1%, and 16.5%. According to the evidence, ARBs have an advantage over the other treatments in reducing the risk of NOD in elderly patients.

Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance

Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.

Beta-blockers for hypertension

BACKGROUND

Beta-blockers refer to a mixed group of drugs with diverse pharmacodynamic and pharmacokinetic properties. They have shown long-term beneficial effects on mortality and cardiovascular disease (CVD) when used in people with heart failure or acute myocardial infarction. Beta-blockers were thought to have similar beneficial effects when used as first-line therapy for hypertension. However, the benefit of beta-blockers as first-line therapy for hypertension without compelling indications is controversial. This review is an update of a Cochrane Review initially published in 2007 and updated in 2012.

OBJECTIVES

To assess the effects of beta-blockers on morbidity and mortality endpoints in adults with hypertension.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials up to June 2016: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 6), MEDLINE (from 1946), Embase (from 1974), and ClinicalTrials.gov. We checked reference lists of relevant reviews, and reference lists of studies potentially eligible for inclusion in this review, and also searched the the World Health Organization International Clinical Trials Registry Platform on 06 July 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least one year of duration, which assessed the effects of beta-blockers compared to placebo or other drugs, as first-line therapy for hypertension, on mortality and morbidity in adults.

DATA COLLECTION AND ANALYSIS

We selected studies and extracted data in duplicate, resolving discrepancies by consensus. We expressed study results as risk ratios (RR) with 95% confidence intervals (CI) and conducted fixed-effect or random-effects meta-analyses, as appropriate. We also used GRADE to assess the certainty of the evidence. GRADE classifies the certainty of evidence as high (if we are confident that the true effect lies close to that of the estimate of effect), moderate (if the true effect is likely to be close to the estimate of effect), low (if the true effect may be substantially different from the estimate of effect), and very low (if we are very uncertain about the estimate of effect).

MAIN RESULTS

Thirteen RCTs met inclusion criteria. They compared beta-blockers to placebo (4 RCTs, 23,613 participants), diuretics (5 RCTs, 18,241 participants), calcium-channel blockers (CCBs: 4 RCTs, 44,825 participants), and renin-angiotensin system (RAS) inhibitors (3 RCTs, 10,828 participants). These RCTs were conducted between the 1970s and 2000s and most of them had a high risk of bias resulting from limitations in study design, conduct, and data analysis. There were 40,245 participants taking beta-blockers, three-quarters of them taking atenolol. We found no outcome trials involving the newer vasodilating beta-blockers (e.g. nebivolol).There was no difference in all-cause mortality between beta-blockers and placebo (RR 0.99, 95% CI 0.88 to 1.11), diuretics or RAS inhibitors, but it was higher for beta-blockers compared to CCBs (RR 1.07, 95% CI 1.00 to 1.14). The evidence on mortality was of moderate-certainty for all comparisons.Total CVD was lower for beta-blockers compared to placebo (RR 0.88, 95% CI 0.79 to 0.97; low-certainty evidence), a reflection of the decrease in stroke (RR 0.80, 95% CI 0.66 to 0.96; low-certainty evidence) since there was no difference in coronary heart disease (CHD: RR 0.93, 95% CI 0.81 to 1.07; moderate-certainty evidence). The effect of beta-blockers on CVD was worse than that of CCBs (RR 1.18, 95% CI 1.08 to 1.29; moderate-certainty evidence), but was not different from that of diuretics (moderate-certainty) or RAS inhibitors (low-certainty). In addition, there was an increase in stroke in beta-blockers compared to CCBs (RR 1.24, 95% CI 1.11 to 1.40; moderate-certainty evidence) and RAS inhibitors (RR 1.30, 95% CI 1.11 to 1.53; moderate-certainty evidence). However, there was little or no difference in CHD between beta-blockers and diuretics (low-certainty evidence), CCBs (moderate-certainty evidence) or RAS inhibitors (low-certainty evidence). In the single trial involving participants aged 65 years and older, atenolol was associated with an increased CHD incidence compared to diuretics (RR 1.63, 95% CI 1.15 to 2.32). Participants taking beta-blockers were more likely to discontinue treatment due to adverse events than participants taking RAS inhibitors (RR 1.41, 95% CI 1.29 to 1.54; moderate-certainty evidence), but there was little or no difference with placebo, diuretics or CCBs (low-certainty evidence).

AUTHORS' CONCLUSIONS

Most outcome RCTs on beta-blockers as initial therapy for hypertension have high risk of bias. Atenolol was the beta-blocker most used. Current evidence suggests that initiating treatment of hypertension with beta-blockers leads to modest CVD reductions and little or no effects on mortality. These beta-blocker effects are inferior to those of other antihypertensive drugs. Further research should be of high quality and should explore whether there are differences between different subtypes of beta-blockers or whether beta-blockers have differential effects on younger and older people.

Background and Treatment of Metabolic Syndrome: A Therapeutic Challenge

Metabolic syndrome is characterized by a clustering of cardiovascular and metabolic risk factors. This syndrome is now widely recognized as a distinct pathologic entity. It is receiving a great deal of attention in the medical literature and also in the lay press. People with metabolic syndrome have a clustering of the following risk factors, including detrimental changes in glucose tolerance and insulin resistance, abdominal (visceral) obesity, atherogenic dyslipidemia, and hypertension. Metabolic syndrome is associated with important cardiovascular and cerebrovascular and metabolic risks. Prevention and treatment are therefore of great importance. Preventive measures involving lifestyle are mandatory. In addition, metabolic syndrome patients will require pharmacologic treatment, usually for the rest of their lives. Complex patterns of drug treatment are required. This review provides an extensive and critical review of the drug treatment of this complex pathologic entity.

Renin-angiotensin-aldosterone system in insulin resistance and metabolic syndrome

Obesity and its consequent complications such as hypertension and metabolic syndrome are increasing in incidence in almost all countries. Insulin resistance is common in obesity. Renin- angiotensin system (RAS) is an important target in the treatment of hypertension and drugs that act on RAS improve insulin resistance and decrease the incidence of type 2 diabetes mellitus, explaining the close association between hypertension and type 2 diabetes mellitus. RAS influences food intake by modulating the hypothalamic expression of neuropeptide Y and orexins via AMPK dephosphorylation. Estrogen reduces appetite by its action on the brain in a way similar to leptin, an anorexigenic action that seems to be mediated via hypothalamic pro-opiomelanocortin (POMC) neurons in the arcuate nucleus and synaptic plasticity in the arcuate nucleus similar to leptin. Estrogen stimulates lipoxin A₄, a potent vasodilator and platelet anti-aggregator. Since both RAS and estrogen act on the hypothalamic neuropeptides and regulate food intake and obesity, it is likely that RAS modulates LXA₄ synthesis. Thus, it is proposed that Angiotensin-II receptor blockers and angiotensin-converting enzymes and angiotensin-II antagonists may have the ability to augment LXA₄ synthesis and thus bring about their beneficial actions.

Effect of Barnidipine on Blood Pressure and Serum Metabolic Parameters in Patients With Essential Hypertension: A Pilot Study

The effect of barnidipine, a calcium channel blocker, on metabolic parameters is not well known. The authors conducted the present pilot study to evaluate the possible effects of barnidipine on parameters involved in atherogenesis, oxidative stress, and clotting activity. This open-label intervention study included 40 adult patients with essential hypertension who received barnidipine 10 mg once daily. Barnidipine significantly reduced systolic and diastolic blood pressure as well as isoprostane levels, which represent a reliable marker of oxidative stress. In contrast, barnidipine had a neutral effect on lipid profile and apolipoprotein levels, did not influence glucose homeostasis, had no effect on renal function, and did not cause any changes in electrolyte levels. Moreover, barnidipine did not affect either the clotting/fibrinolytic status (evaluated by measurement of fibrinogen, total plasminogen activator inhibitor, tissue plasminogen activator, and a2 antiplasmin) or the enzymatic activity of the inflammatory/anti-inflammatory mediators lipoprotein-associated phospholipase A2 and paraoxonase 1, respectively. Barnidipine should be mainly considered as an antihypertensive agent with neutral effects on most of the studied metabolic parameters in hypertensive patients. Any antioxidant effect of barnidipine needs further investigation.

Diabetes Mellitus and Heart Failure

Diabetes mellitus and heart failure are two multifaceted entities characterised by high morbidity and mortality. Early epidemiological and prospective studies have observed the frequent co-existence of both conditions. Importantly, diabetes mellitus can precipitate or worsen heart failure due to the accumulation of advanced glycation end products, oxidative stress, inflammatory status impairment, decay of intracellular calcium, changes in microRNAs expression, not to mention atherosclerosis progression and coronary artery disease. Heart failure also impairs glucose metabolism through less well-known mechanisms. Attention must especially be given in the treatment as there are frequently adverse interactions between the two diseases and novel agents against diabetic cardiomyopathy are under investigation. As several missing links still exist in the connection between heart failure and diabetes mellitus we will review, in this article, the most recent data underlying the interaction of them and provide an overview of the most important clinical perspectives.

Beta-blockers for hypertension

BACKGROUND

This review is an update of the Cochrane Review published in 2007, which assessed the role of beta-blockade as first-line therapy for hypertension.

OBJECTIVES

To quantify the effectiveness and safety of beta-blockers on morbidity and mortality endpoints in adults with hypertension.

SEARCH METHODS

In December 2011 we searched the Cochrane Central Register of Controlled Trials, Medline, Embase, and reference lists of previous reviews; for eligible studies published since the previous search we conducted in May 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least one year duration, which assessed the effects of beta-blockers compared to placebo or other drugs, as first-line therapy for hypertension, on mortality and morbidity in adults.

DATA COLLECTION AND ANALYSIS

We selected studies and extracted data in duplicate. We expressed study results as risk ratios (RR) with 95% confidence intervals (CI) and combined them using the fixed-effects or random-effects method, as appropriate.

MAIN RESULTS

We included 13 RCTs which compared beta-blockers to placebo (4 trials, N=23,613), diuretics (5 trials, N=18,241), calcium-channel blockers (CCBs: 4 trials, N=44,825), and renin-angiotensin system (RAS) inhibitors (3 trials, N=10,828). Three-quarters of the 40,245 participants on beta-blockers used atenolol. Most studies had a high risk of bias; resulting from various limitations in study design, conduct, and data analysis.Total mortality was not significantly different between beta-blockers and placebo (RR 0.99, 95%CI 0.88 to 1.11; I(2)=0%), diuretics or RAS inhibitors, but was higher for beta-blockers compared to CCBs (RR 1.07, 95%CI 1.00 to 1.14; I(2)=2%). Total cardiovascular disease (CVD) was lower for beta-blockers compared to placebo (RR 0.88, 95%CI 0.79 to 0.97; I(2)=21%). This is primarily a reflection of the significant decrease in stroke (RR 0.80, 95%CI 0.66 to 0.96; I(2)=0%), since there was no significant difference in coronary heart disease (CHD) between beta-blockers and placebo. There was no significant difference in withdrawals from assigned treatment due to adverse events between beta-blockers and placebo (RR 1.12, 95%CI 0.82 to 1.54; I(2)=66%).The effect of beta-blockers on CVD was significantly worse than that of CCBs (RR 1.18, 95%CI 1.08-1.29; I(2)=0%), but was not different from that of diuretics or RAS inhibitors. In addition, there was an increase in stroke in beta-blockers compared to CCBs (RR 1.24, 95%CI 1.11-1.40; I(2)=0%) and RAS inhibitors (RR 1.30, 95%CI 1.11 to 1.53; I(2)=29%). However, CHD was not significantly different between beta-blockers and diuretics, CCBs or RAS inhibitors. Participants on beta-blockers were more likely to discontinue treatment due to adverse events than those on RAS inhibitors (RR 1.41, 95% CI 1.29 to 1.54; I(2)=12%), but there was no significant difference with diuretics or CCBs.

AUTHORS' CONCLUSIONS

Initiating treatment of hypertension with beta-blockers leads to modest reductions in cardiovascular disease and no significant effects on mortality. These effects of beta-blockers are inferior to those of other antihypertensive drugs. The GRADE quality of this evidence is low, implying that the true effect of beta-blockers may be substantially different from the estimate of effects found in this review. Further research should be of high quality and should explore whether there are differences between different sub-types of beta-blockers or whether beta-blockers have differential effects on younger and elderly patients.

Management of hypertension with the fixed combination of perindopril and amlodipine in daily clinical practice: results from the STRONG prospective, observational, multicenter study

BACKGROUND

Current clinical guidelines recognize that the use of more than one agent is necessary to achieve target BP in the majority of patients. The ASCOT-BPLA trial demonstrated that the free combination of amlodipine and perindopril effectively controlled BP and was better than a beta-adrenoceptor antagonist (beta-blocker)/diuretic combination in reducing total mortality and cardiovascular outcomes.

OBJECTIVE

To evaluate the efficacy and tolerability of a fixed combination of perindopril and amlodipine in the clinical setting.

STUDY DESIGN

The STRONG (SafeTy & efficacy analysis of coveRsyl amlodipine in uncOntrolled and Newly diaGnosed hypertension) study was a prospective, observational, multicenter trial.

SETTING

This was a naturalistic, real-world, clinic-based, outpatient study involving 336 general practitioners/primary care physicians in 65 cities in India.

PATIENTS

Adults aged 40-70 years with newly diagnosed/untreated stage 2 hypertension (BP >/=160/100 mmHg), hypertension uncontrolled with monotherapy (BP >140/90 mmHg), or hypertension inadequately managed with another combination therapy.

INTERVENTION

Fixed combination perindopril 4 mg/amlodipine 5 mg once daily for 60 days.

MAIN OUTCOMES MEASURE

The primary outcomes were the mean change in BP from baseline and the proportion of patients achieving adequate BP control (</=140/90 mmHg, or </=130/80 mmHg in patients with diabetes mellitus) in the intent-to-treat (ITT) population. Secondary analyses included incidence of adverse events (ITT) and treatment adherence rate (completers).

RESULTS

In total, 1250 patients comprised the ITT population: 32.6% with newly diagnosed hypertension; 40.5% with hypertension uncontrolled with monotherapy; and 26.9% with hypertension inadequately managed with another combination therapy. Mean SBP/DBP decreased significantly from baseline (167.4 +/- 15.2/101.4 +/- 9.1 mmHg) over 60 days (-41.9 +/- 34.8/-23.2 +/- 21.8 mmHg; p < 0.0001). Target BP was achieved in 66.1% of patients in the total population, 68.3% of untreated patients, 68.4% of patients uncontrolled with monotherapy, and 59.9% of patients inadequately managed with combination therapy. In 161 patients with SBP >180 mmHg at baseline (newly diagnosed: n = 50; uncontrolled on monotherapy: n = 53; inadequately managed on combination therapy: n = 58), BP was reduced by 63.2 +/- 32.5/29.0 +/- 21.9 mmHg (p < 0.0001) at day 60. The fixed combination was safe and well tolerated. All 1175 patients completing the 60-day study (94%) adhered to their treatment regimen.

CONCLUSION

Fixed combination perindopril/amlodipine was found to be an effective and well tolerated antihypertensive treatment, with an excellent rate of treatment adherence in the clinical setting. Fixed combination perindopril/amlodipine is expected to be useful in the management of hypertension in primary healthcare, with a positive impact on treatment adherence.

Beta-blockers for hypertension

BACKGROUND

This review is an update of the Cochrane Review published in 2007, which assessed the role of beta-blockade as first-line therapy for hypertension.

OBJECTIVES

To quantify the effectiveness and safety of beta-blockers on morbidity and mortality endpoints in adults with hypertension.

SEARCH METHODS

In December 2011 we searched the Cochrane Central Register of Controlled Trials, Medline, Embase, and reference lists of previous reviews; for eligible studies published since the previous search we conducted in May 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least one year duration, which assessed the effects of beta-blockers compared to placebo or other drugs, as first-line therapy for hypertension, on mortality and morbidity in adults.

DATA COLLECTION AND ANALYSIS

We selected studies and extracted data in duplicate. We expressed study results as risk ratios (RR) with 95% confidence intervals (CI) and combined them using the fixed-effects or random-effects method, as appropriate.

MAIN RESULTS

We included 13 RCTs which compared beta-blockers to placebo (4 trials, N=23,613), diuretics (5 trials, N=18,241), calcium-channel blockers (CCBs: 4 trials, N=44,825), and renin-angiotensin system (RAS) inhibitors (3 trials, N=10,828). Three-quarters of the 40,245 participants on beta-blockers used atenolol. Most studies had a high risk of bias; resulting from various limitations in study design, conduct, and data analysis.Total mortality was not significantly different between beta-blockers and placebo (RR 0.99, 95%CI 0.88 to 1.11; I(2)=0%), diuretics or RAS inhibitors, but was higher for beta-blockers compared to CCBs (RR 1.07, 95%CI 1.00 to 1.14; I(2)=2%). Total cardiovascular disease (CVD) was lower for beta-blockers compared to placebo (RR 0.88, 95%CI 0.79 to 0.97; I(2)=21%). This is primarily a reflection of the significant decrease in stroke (RR 0.80, 95%CI 0.66 to 0.96; I(2)=0%), since there was no significant difference in coronary heart disease (CHD) between beta-blockers and placebo. There was no significant difference in withdrawals from assigned treatment due to adverse events between beta-blockers and placebo (RR 1.12, 95%CI 0.82 to 1.54; I(2)=66%).The effect of beta-blockers on CVD was significantly worse than that of CCBs (RR 1.18, 95%CI 1.08-1.29; I(2)=0%), but was not different from that of diuretics or RAS inhibitors. In addition, there was an increase in stroke in beta-blockers compared to CCBs (RR 1.24, 95%CI 1.11-1.40; I(2)=0%) and RAS inhibitors (RR 1.30, 95%CI 1.11 to 1.53; I(2)=29%). However, CHD was not significantly different between beta-blockers and diuretics, CCBs or RAS inhibitors. Participants on beta-blockers were more likely to discontinue treatment due to adverse events than those on RAS inhibitors (RR 1.41, 95% CI 1.29 to 1.54; I(2)=12%), but there was no significant difference with diuretics or CCBs.

AUTHORS' CONCLUSIONS

Initiating treatment of hypertension with beta-blockers leads to modest reductions in cardiovascular disease and no significant effects on mortality. These effects of beta-blockers are inferior to those of other antihypertensive drugs. The GRADE quality of this evidence is low, implying that the true effect of beta-blockers may be substantially different from the estimate of effects found in this review. Further research should be of high quality and should explore whether there are differences between different sub-types of beta-blockers or whether beta-blockers have differential effects on younger and elderly patients.

Statin use and the risk of incident diabetes mellitus: a review of the literature

Statins are one of the most widely prescribed medications in the world. They are beneficial in both the primary and secondary prevention of atherosclerotic cardiovascular disease events. In recent years, however, concern has been raised regarding an increased incidence of new-onset diabetes mellitus observed in clinical trials of statin therapy. While most randomized, placebo controlled, statin trials have not included the incidence of new-onset diabetes as a major primary end point, a very small but consistent adverse effect on glycosylated hemoglobin and blood glucose levels, which is presently of unknown clinical significance, has been observed. Importantly, it should be remembered that some patient subgroups exposed to statin therapy, such as those with the metabolic syndrome, may already be particularly vulnerable to developing diabetes mellitus. Experimentally, although the weight of evidence suggests a protective effect of statins on the development of diabetes mellitus, basic science studies have documented conflicting evidence regarding both the beneficial and adverse effects from statin therapy on insulin secretion and sensitivity. In addition, the possibility that statin-induced muscle inflammation may elevate blood glucose levels cannot be excluded. Thus, although the biological plausibility of statins inducing diabetes certainly may exist, at the present time, sufficient high-quality scientific evidence does not exist to definitively establish the veracity or the strength of any putative cause and effect relationship. And without such evidence, there is no current impetus to alter existing clinical practice recommendations regarding the appropriate use of statin therapy.

Impact of trandolapril therapy and its combination with a calcium channel blocker on plasma adiponectin levels in patients with type 2 diabetes and hypertension

INTRODUCTION

Adiponectin is secreted from adipose tissue and exhibits a protective effect against cardiovascular disease; plasma adiponectin concentrations are decreased in type 2 diabetic and in hypertensive patients.

OBJECTIVE

The aim of this study was to compare the effect of trandolapril (T) and its fixed-dose combination with verapamil (FDTV) on adiponectin levels in hypertensive type 2 diabetic patients.

METHODS

A total of 40 type 2 diabetic patients with never-treated hypertension were randomly assigned to two groups. One group received FDTV 180 mg + T 2 mg, once a day; the other group received T 2 mg once a day, administered for 3 months in both groups. Adiponectin was measured by enzyme-linked immunosorbent assay (ELISA) at the beginning and end of the study. Patients were evaluated monthly for blood pressure, fasting serum glucose and adverse events. Statistical analysis was performed with analysis of variance (ANOVA).

RESULTS

All patients experienced a significant reduction of blood pressure. Both therapeutics regimens increased the levels of adiponectin, However, FDTV produces a higher increase in the levels of the hormone (8.15 ± 4.6 to 10.96 ± 5.6 µg/ml) when compared with the T treatment (7.64 ± 3.8 to 8.92 ± 4.4 µg/ml), p < 0.05. None of the patients suffered adverse events.

CONCLUSION

Our results show that the addition of FDTV to T produced a greater increase on adiponectin levels than trandolapril alone.

Establishing targets for hypertension control in patients with comorbidities

Most current guidelines recommend tighter blood pressure (BP) control in hypertensive patients with comorbidities. These recommendations are based on epidemiologic data indicating that cardiovascular risk increases at lower BP levels in hypertensive patients with comorbidities than in those without comorbidities. Hypertension guidelines usually reflect outcomes from previous studies, but current recommendations for patients with comorbidities have preceded the evidence. We review recent studies investigating whether these new targets can be achieved, whether they are well tolerated, and whether they positively affect the outcomes. The results of the few current studies about outcomes in lower BP target groups are either negative or somewhat--but not decidedly--positive. There is a need for new trials designed to evaluate the validity of current recommendations for tighter BP control in hypertensive patients with comorbidities. Additionally, existing data from published trials could be reanalyzed to provide further clarification.

MicroRNA-155 regulates angiotensin II type 1 receptor expression and phenotypic differentiation in vascular adventitial fibroblasts

MicroRNAs (miRNAs), which are genomically encoded small RNAs, negatively regulate target gene expression at the post-transcriptional level. Our recent study indicated that microRNA-155 (miR-155) might be negatively correlated with blood pressure, and it has been suggested that miR-155-mediated target genes could be involved in the cardiovascular diseases. Bioinformatic analyses predict that angiotensin II type 1 receptor (AT(1)R) is a miR-155 target gene. The present study investigated the potential role of miR-155 in regulating AT(1)R expression and phenotypic differentiation in rat aortic adventitial fibroblasts (AFs). Luciferase assay demonstrated that miR-155 suppressed AT(1)R 3'-UTR reporter construct activity. miR-155 overexpression in AFs did not reduce target mRNA levels, but significantly reduced target protein expression. In addition, AFs transfected with pSUPER/miR-155 exhibited reduced Ang II-induced ERK1/2 activation. miR-155 overexpression in cells attenuated Ang II-induced α-smooth muscle actin (α-SMA, produces myofibroblast) expression, but did not transform growth factor beta-1 (TGF-β1). This study demonstrated that miR-155 could have an important role in regulating adventitial fibroblast differentiation and contribute to suppression of AT(1)R expression.

Beneficial effect of combination therapy comprising angiotensin II receptor blocker plus calcium channel blocker on plasma adiponectin levels

The study aim was to examine the effect of combination therapy comprising angiotensin receptor blocker plus calcium antagonist on post-treatment plasma adiponectin levels compared to pretreatment levels. There was a significant gender difference in the relationship between preadiponectin level and age. In the search for contributing factors for treatment-based changes in adiponectin levels, these effects of gender and age were considered in statistical analysis. The adiponectin level in the combination therapy group was further increased compared to that in each of the monotherapy groups, despite there being no significant difference in antihypertensive effect, indicating that the combined medication provided an effect beyond that of lowering blood pressure.

Immediate but not long-term administration of nicardipine inhibits tolbutamide-induced insulin secretion from rat pancreatic beta cells

OBJECTIVES

Calcium channel blockers alter glucose homeostasis, but sufficient data regarding this effect in healthy animals have not been provided. We test the effect of nicardipine on beta cell function in healthy rats.

METHODS

Islets from Sprague-Dawley rats were coincubated with nicardipine, tolbutamide, or their combination for 1 hour. Insulin secretion was measured by radioimmunoassay. The rats were given nicardipine, tolbutamide, or their combination by intravenous injection. Intravenous glucose tolerance tests were performed after the first drug administration and 4 weeks later. Pancreata were excised for assessment of insulin content and immunohistochemical staining in the end.

RESULTS

Nicardipine markedly inhibited not only the insulin secretion by islets per se but also that enhanced by tolbutamide in vitro. Blood glucose was reduced by tolbutamide in vivo but elevated by nicardipine abruptly in parallel with retarded insulin secretion. Long-term administration of nicardipine altered neither fasting blood glucose level nor fasting serum insulin level, whereas pancreatic insulin content was unmodified despite that nicardipine caused shrunken islets with weak immunoreactivity of beta cells by immunohistochemistry.

CONCLUSIONS

In healthy rats, immediate administration of nicardipine inhibits insulin secretion of beta cells both in vitro and in vivo but does not exert a deleterious effect in vivo after long-term treatment.

β-Adrenergic Antagonists in Hypertension: A Review of the Evidence

Objective:

To evaluate the effects of β-adrenergic antagonist therapy on cardiovascular and cerebrovascular outcomes in the treatment of hypertension.

Data Sources:

Literature searches were conducted using MEDLINE (1966–August 2009), International Pharmaceutical Abstracts (1970–August 2009), and Cochrane Database of Systematic Reviews (until third quarter 2009) to locate clinical trials and meta-analyses comparing β-blocker therapy with placebo or other antihypertensive agents in patients with hypertension. Bibliographies from relevant research and review articles were reviewed for additional references.

Study Selection and Data Extraction:

All English-language articles identified from the data sources were reviewed. Articles describing original research with cardiovascular or cerebrovascular outcomes and/or death as either primary or secondary endpoints were included. Articles describing the use of β-blocker therapy for conditions other than hypertension were not included,

Data Synthesis:

Five placebo-controlled studies and 10 active-controlled studies were reviewed. In addition, 11 meta-analyses were evaluated. Placebo-controlled trials of β-blockers in hypertension provide evidence of reduced risk for stroke, cardiovascular events, and heart failure. Only 2 studies comparing β-blockers with other antihypertensives found significant benefit with β-blockers. However, the majority of meta-analyses comparing β-blockers with other antihypertensive agents show increased risk for stroke with β-blockers, and some data suggest increased risk for cardiovascular events and all-cause mortality. The majority of data results from studies of atenolol, and many studies employed combination antihypertensive therapies, which often included thiazide diuretics.

Conclusions:

Overall, data supporting β-blockers as preferred therapy in hypertension are inadequate. Although most negative cardiovascular and cerebrovascular outcomes of β-blockers were associated with atenolol therapy, data supporting other β-blockers in hypertension are lacking.

Role of beta-adrenergic receptor blocking agents in hypertensive diseases: personal thoughts as the controversy persists

The long history of the beta-adrenergic receptor blockers for the treatment of hypertension is fraught with many controversies. The first compound had severe untoward effects preventing their use until propranolol was introduced. It was found effective for treatment of angina pectoris since not all patients with hypertension responded to monotherapy with a meaningful reduction of pressure. Nevertheless, the beta-blockers were most effective in: younger patients, especially with hyperkinetic circulation; with co-morbid diseases (e.g. coronary arterial disease with or without prior myocardial infarction); or when used with a diuretic. Subsequently with the advent of meta-analysis to evaluate more generalized experience, controversy resumed with statements made to exclude beta-blockers for initial hypertensive therapy. Support for this argument was gained with reports of patients developing 'dysglycemia' with treatment. However, exclusion of any one therapeutic class for a multifactorial disease such as hypertension seems unrealistic. Meta-analysis confounded this conclusion since inadequate numbers of patients having specific clinical and biological characteristics were included (especially young patients). This is particularly important at this time when third-party reimbursement procedures are particularly relevant and when the primary care physician must deal with the individual patient. The NICE report has introduced specific thinking along these lines. In-and-of itself, its recommendations are reasonable, but current articles continue to suggest that the 'older' beta-blockers should be excluded from national guidelines for initial antihypertensive therapy. Personally, I disagree; and, no doubt, controversy will continue.

Antihypertensive medications: benefits of blood pressure lowering and hazards of metabolic effects

Blood pressure reduction is associated with significant reduction in adverse cardiovascular outcomes. Certain blood pressure-lowering drugs have adverse effects on glucose homeostasis, and have been associated with the development of both prediabetes and diabetes during use. There is controversy over the significance of diabetes that develops during treatment with antihypertensives and whether the benefits of blood pressure reduction offset the hazards of dysglycemia that can lead to diabetes. Many treatment guidelines have recently undergone revisions to include consideration for the metabolic effects of antihypertensive drugs, particularly in high-risk populations. This review summarizes the data related to the benefits of blood pressure reduction as well as the adverse metabolic effects and new-onset diabetes associated with some medications.

Angiotensin-converting enzyme (ACE) inhibitors modulate cellular retinol-binding protein 1 and adiponectin expression in adipocytes via the ACE-dependent signaling cascade

Inhibitors of the angiotensin-converting enzyme (ACE) decrease angiotensin II production and activate an intracellular signaling cascade that affects gene expression in endothelial cells. Because ACE inhibitors have been reported to delay the onset of type 2 diabetes, we determined ACE signaling-modulated gene expression in endothelial cells and adipocytes. Using differential gene expression analysis, several genes were identified that were 3-fold up- or down-regulated by ramiprilat in cells expressing wild-type ACE versus cells expressing a signaling-dead ACE mutant. One up-regulated gene was the cellular retinol-binding protein 1 (CRBP1). In adipocytes, the overexpression of CRBP1 enhanced (4- to 5-fold) the activity of promoters containing response elements for retinol-dependent nuclear receptors [retinoic acid receptor (RAR) and retinoid X receptor (RXR)] or peroxisome proliferator-activated receptors (PPAR). CRBP1 overexpression also enhanced the promoter activity (by 470 +/- 40%) and expression/release of the anti-inflammatory and antiatherogenic adipokine adiponectin (cellular adiponectin by 196 +/- 24%, soluble adiponectin by 228 +/- 74%). Significantly increased adiponectin secretion was also observed after ACE inhibitor treatment of human preadipocytes, an effect prevented by small interfering RNA against CRBP1. Furthermore, in ob/ob mice, ramipril markedly potentiated both the basal (approximately 2-fold) and rosiglitazonestimulated circulating levels of adiponectin. In patients with coronary artery disease or type 2 diabetes, ACE inhibition also significantly increased plasma adiponectin levels (1.6- or 2.1-fold, respectively). In summary, ACE inhibitors affect adipocyte homeostasis via CRBP1 through the activation of RAR/RXR-PPAR signaling and up-regulation of adiponectin. The latter may contribute to the beneficial effects of ACE inhibitors on the development of type 2 diabetes in patients with an activated renin-angiotensin system.

Cardiovascular drugs as antidiabetic agents: evidence for the prevention of type 2 diabetes

Given the long-term health consequences and increasing incidence of type 2 diabetes, there is great interest to potentially prevent or delay its onset. Primary prevention studies have demonstrated that intensive exercise and weight reduction, and to a lesser extent certain antidiabetic agents, can reduce new onset diabetes in at-risk individuals. Results from post hoc analyses and secondary end-point outcomes of large randomized controlled trials of cardiovascular drugs suggest that these may also have beneficial effects, reducing the incidence of new onset diabetes in addition to their proven cardiovascular benefits. Multiple meta-analyses confirm that drugs primarily acting on the renin-angiotensin system (RAS) reduce the incidence of diabetes in the populations studied, perhaps via improved insulin sensitivity and/or effects on pancreatic beta cells. However, results from the recent Diabetes REduction Approaches with Medication study specifically failed to show a significant reduction in the incidence of diabetes with ramipril in individuals with abnormal glucose tolerance at baseline. There is only limited evidence that statins improve glucose tolerance, and although beta-blockers tend to have detrimental effects on glucose tolerance, newer agents with vasodilatory properties may confer benefits. With current guidelines, the use of cardiovascular drugs modifying the RAS will increase in at-risk individuals, but at present, they cannot be recommended to prevent diabetes.

Effects of sympatholytic therapy with moxonidine on serum adiponectin levels in hypertensive women

We examined whether moxonidine influences lipid profile, insulin resistance, adiponectin levels, renal function and microalbuminuria in women with essential hypertension in a study of 55 non-diabetic hypertensive patients and 53 normotensive women. Hypertensive patients received moxonidine for 12 weeks. At baseline the hypertensive group had significantly higher mean blood pressure, low-density lipoprotein cholesterol, triglycerides, total cholesterol, fasting glucose, urinary albumin excretion and homeostasis model assessment of insulin resistance (HOMA-IR), together with significantly lower mean high-density lipoprotein cholesterol, creatinine clearance and serum adiponectin than the normotensive group. Moxonidine significantly decreased blood pressure, fasting glucose, triglycerides, total cholesterol, HOMA-IR and albumin excretion, but significantly increased serum adiponectin. The change in adiponectin level was negatively correlated with the change in HOMA-IR. Moxonidine treatment may improve unfavourable metabolic status related to insulin resistance by increasing adiponectin levels in patients with essential hypertension. Since it can improve adiponectin levels, it may be used in the antihypertensive treatment of patients at high risk of diabetes and cardiovascular disease.

Metabolic side effects and cardiovascular events of diuretics: should a diuretic remain the first choice therapy in hypertension treatment? The case of yes

Essential hypertension is a major cause of cardiovascular morbidity and mortality in the Western world. Numerous clinical trials have demonstrated that the treatment of hypertension results in a substantial reduction of hypertension-related morbidity and mortality. The efficacy and safety of diuretics has been shown in many clinical trials. Like most other antihypertensive agents, the side effects of diuretics are mostly benign and mild. The metabolic side effects of diuretics, however, have been a bone of contention for a long time. In this paper, we describe the most important and frequent metabolic side effects of diuretics, and emphasize particularly the non-life-threatening effect of diuretics on ventricular arrhythmias due to their hypokalemic effect, the detection of the new onset diabetes (perhaps caused by the administration of diuretics itself), and their significant beneficial effect on cardiovascular and cerebrovascular morbidity and mortality. At the end of the article, we highlighted the differences regarding the prescription of diuretics between the recently published American and European Guidelines of hypertension.

Metabolic and clinical outcomes in nondiabetic individuals with the metabolic syndrome assigned to chlorthalidone, amlodipine, or lisinopril as initial treatment for hypertension: a report from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

OBJECTIVE

Optimal initial antihypertensive drug therapy in people with the metabolic syndrome is unknown.

RESEARCH DESIGN AND METHODS

We conducted a subgroup analysis of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) to compare metabolic, cardiovascular, and renal outcomes in individuals assigned to initial hypertension treatment with a thiazide-like diuretic (chlorthalidone), a calcium channel blocker (CCB; amlodipine), or an ACE inhibitor (lisinopril) in nondiabetic individuals with or without metabolic syndrome.

RESULTS

In participants with metabolic syndrome, at 4 years of follow-up, the incidence of newly diagnosed diabetes (fasting glucose >or=126 mg/dl) was 17.1% for chlorthalidone, 16.0% for amlodipine (P = 0.49, chlorthalidone vs. amlodipine) and 12.6% for lisinopril (P < 0.05, lisinopril vs. chlorthalidone). For those without metabolic syndrome, the rate of newly diagnosed diabetes was 7.7% for chlorthalidone, 4.2% for amlodipine, and 4.7% for lisinopril (P < 0.05 for both comparisons). There were no differences in relative risks (RRs) for outcomes with amlodipine compared with chlorthalidone in those with metabolic syndrome; in those without metabolic syndrome, there was a higher risk for heart failure (RR 1.55 [95% CI 1.25-1.35]). In comparison with lisinopril, chlorthalidone was superior in those with metabolic syndrome with respect to heart failure (1.31 [1.04-1.64]) and combined cardiovascular disease (CVD) (1.19 [1.07-1.32]). No significant treatment group-metabolic syndrome interaction was noted.

CONCLUSIONS

Despite a less favorable metabolic profile, thiazide-like diuretic initial therapy for hypertension offers similar, and in some instances possibly superior, CVD outcomes in older hypertensive adults with metabolic syndrome, as compared with treatment with CCBs and ACE inhibitors.

Doxazosin in metabolically complicated hypertension

Metabolic syndrome, a cluster of metabolic abnormalities with visceral obesity and insulin resistance as its central component, is highly prevalent among hypertensive patients. Hypertension complicated by metabolic syndrome is associated with an increased risk of cardiovascular disease and new-onset Type II diabetes mellitus that further aggravates the prognostic outlook. Such a complex condition requires a multifactorial intervention including blood pressure lowering, improvement of the adverse metabolic profile and delayed onset of new diabetes. In this respect, doxazosin and other alpha-1 adrenoceptor blocking agents are of interest given their effect on the lipid profile in dyslipidemic, obese hypertensive patients, either diabetic or not. Doxazosin improves insulin sensitivity, apparently by accelerating insulin and glucose disposal through vasodilatation of skeletal muscle vascular beds. Whether long-term treatment with the drug might delay, or possibly prevent, incident Type II diabetes in hypertension complicated by metabolic syndrome is an intriguing possibility to be tested in appropriately designed clinical trials.

Effect of valsartan addition to amlodipine on insulin sensitivity in overweight-obese hypertensive patients

OBJECTIVE

The aim of the study was to evaluate the effect of valsartan/amlodipine combination on insulin sensitivity in overweight-obese hypertensive patients.

METHODS

After a 4-week placebo period, 58 overweight-obese (BMI >or=25 kg/m(2)) patients, with mild to moderate essential hypertension (DBP >95 and <110 mmHg, SBP >140 mmHg) were treated with amlodipine 5 mg od or valsartan 160 mg od or amlodipine 5 mg plus valsartan 160 mg od for 8 weeks according to a randomized, open-label, blinded end-point, cross-over study. At the end of the placebo period and each treatment period, blood pressure (BP) and insulin sensitivity (IS) (by euglycemic hyperinsulinemic clamp technique) were evaluated. IS was expressed as the amount of glucose infused during the last 30 min (glucose infusion rate, GIR) in mg/kg/min.

RESULTS

Valsartan/amlodipine combination produced a significantly greater decrease in SBP/DBP values (-22.3/16.7 mmHg, p<0.001 vs baseline) than valsartan (-15.2/11.7 mmHg, p<0.01 vs baseline) and amlodipine monotherapy (-16.1/12.6 mmHg, p<0.01 vs baseline). Both valsartan and amlodipine provided a significant increase in GIR (+1.24 mg/kg/min, p=0.036 vs baseline and +1.02 mg/kg/min, p=0.047, respectively), but such an increase was significantly greater with their combination (+1.82 mg/kg/min, p<0.01 vs baseline). These greater changes in IS were not related to BP changes.

CONCLUSION

Valsartan/amlodipine combination improved IS more than respective monotherapy beyond affording greater BP reductions. This strengthens the rationale to use valsartan/amlodipine combination in the treatment of overweight-obese hypertensives.

Effects of perindopril in hypertensive patients with or without type 2 diabetes mellitus, and with altered insulin sensitivity

Impaired insulin sensitivity and hypertension are risk factors for atherosclerosis, which in turn leads to a variety of cardiovascular diseases. In both conditions, the risks of morbidity and mortality appear to be further increased. Impaired insulin sensitivity is also a precursor for diabetes. The renin-angiotensin-aldosterone system (RAAS) is implicated in the development of both hypertension and insulin resistance. Antihypertensive agents that act by blocking the RAAS, such as angiotensin-converting enzyme (ACE) inhibitors, may improve insulin sensitivity and therefore prevent the deleterious consequences of insulin resistance, including type 2 diabetes. ACE inhibitors appear to improve insulin sensitivity in patients with hypertension and insulin resistance, including diabetes. This review assesses the literature surrounding the use of the ACE inhibitor perindopril in patients with hypertension and varying degrees of insulin resistance, including the effects of perindopril in preventing the development of diabetes and subsequent cardiovascular morbidity and mortality.

Is the development of diabetes with antihypertensive therapy a problem?--Pro

Some questions about new-onset diabetes (NOD) must still be completely addressed: 1) its incidence; 2) the possible association between NOD and some classes of antihypertensive drugs; and 3) its prognostic impact. It is well known that diuretics and beta blockers can increase plasma glucose and, in available hypertension trials, diuretics and beta blockers caused a higher incidence of NOD than new antihypertensive drugs. NOD heralds a high risk of major cardiovascular events, but the absolute difference between old and new drugs was too small to significantly drive the differences in cardiovascular event rates between the two groups of treatment. This evidence suggests a judicious use of drugs more frequently associated with NOD in subjects at high risk of diabetes (impaired fasting glucose, overweight, family history of diabetes, low high-density lipoprotein cholesterol levels). The lowest effective dose of these drugs should be used, plasma glucose should be checked periodically, and concomitant lifestyle measures to prevent diabetes should be implemented with resolution.

The development of new-onset type 2 diabetes associated with choosing a calcium channel blocker compared to a diuretic or beta-blocker

OBJECTIVE

It has been acknowledged that patients who receive a beta-blocker or diuretic based regimen are at increased risk of developing new-onset diabetes. Recently, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have been shown to decrease patients' odds of developing new-onset type 2 diabetes. A number of large placebo-controlled multi-center trials in post-myocardial infarction and heart failure patients have shown the ability of renin-angiotensin-aldosterone system medications to reduce the onset of type 2 diabetes. Pharmacologic data has shown improved insulin sensitivity with ACEIs and ARBs. Controversy persists regarding the influence of calcium channel blockers on the development of new-onset diabetes.

RESEARCH DESIGN AND METHODS

Two reviewers conducted a systematic literature search of Medline, EMBASE, CINAHL, and the Cochrane Library (1966 to December 2006) to extract a consensus of trial data involving calcium channel blockers versus diuretics or beta-blockers with an endpoint of new-onset type 2 diabetes. Studies were included if they were randomized controlled trials versus routine treatment, not observational studies of clinical practice. A random-effects model was utilized. Subgroup and sensitivity analyses were conducted.

RESULTS

Out of 1721 trials, six meeting inclusion criteria were identified, including 99 006 patients. Calcium channel blockers were associated with a reduced incidence of new-onset type 2 diabetes (odds ratio 0.81; 95% confidence interval [CI] 0.73-0.90; p = 0.0001) compared with diuretic or beta-blocker therapy. The reduction in new-onset type 2 diabetes was maintained when a calcium channel blocker was compared to only thiazide diuretics (OR 0.86; 95% CI 0.75-0.99; p = 0.0346). The meta-analysis was limited by the varying definition of new-onset type 2 diabetes mellitus, as well as the potential for publication bias, which is a limit of any meta-analysis.

CONCLUSIONS

Calcium channel blockers may be associated with reduced odds of developing new-onset type 2 diabetes compared to diuretics and beta-blockers.

Pathophysiologic, Diagnostic, and Therapeutic Aspects of the Metabolic Syndrome

The metabolic syndrome, characterized by increases in waist circumference, blood pressure, and triglyceride concentrations combined with reduced high-density lipoprotein and evidence of glucose intolerance, results from the interaction of visceral or central obesity with insulin resistance. This syndrome presents a clinical situation of systemic inflammation and increased cardiovascular risk. Blood pressure, even if only in the "prehypertensive" range, plays an important role in increasing the risk of cardiovascular disease. Recognition and treatment of each individual component of the metabolic syndrome is critical in reducing cardiovascular risk. Treatment should begin with lifestyle changes, including diet, exercise, and weight reduction. Antihypertensive therapy should be directed toward reduction of blood pressure to levels as close to optimal (<120/80 mm Hg) as feasible, and treatment protocols that do not cause worsening of glucose intolerance should be selected. Therapy for dyslipidemia should be directed at reducing triglycerides and increasing high-density lipoprotein. Glucose-lowering agents may be indicated, and drugs such as metformin and thiazolidinediones, which reduce insulin resistance, should form the basis of therapy. Carefully chosen therapy will effectively improve cardiovascular outcomes.

Indapamide Decreases Plasma Adiponectin Concentration in Patients with Essential Hypertension

BACKGROUND/AIM

Adiponectin is an adipose tissue-specific protein with antiatherogenic and insulin-sensitizing properties. In patients with essential hypertension, plasma adiponectin concentrations are lower than in healthy subjects. Antihypertensive drugs do not uniformly influence components of the metabolic syndrome. Therefore, the aim of this study was to evaluate the influence of 6 months' monotherapy with different antihypertensive drugs on plasma adiponectin concentration in essential hypertension patients.

METHODS

Forty essential hypertension patients were randomized to receive enalapril, metoprolol, amlodipine or indapamide. Plasma concentrations of adiponectin, insulin, glucose and body fat content were estimated twice: before and after 6 months of antihypertensive monotherapy.

RESULTS

Plasma adiponectin concentration did not change significantly after enalapril (11.5 +/- 4.8 vs. 11.1 +/- 4.1 mg/l), metoprolol (10.2 +/- 4.2 vs. 9.8 +/- 4.5 mg/l), and amlodipine (9.0 +/- 6.0 vs. 8.5 +/- 5.4 mg/l) treatment. However, a significant decrease of plasma adiponectin concentration (from 11.6 +/- 4.6 to 10.2 +/- 4.2 mg/l, p = 0.047) was observed in patients treated with indapamide. Additionally in these patients, a significant increase of the HOMA-IR index was found (p = 0.021).

CONCLUSION

Treatment with indapamide was followed by a significant decrease of plasma adiponectin concentration. This may participate in the pathogenesis of carbohydrate metabolism disturbances often found in patients treated with thiazide-type diuretics.

Reducing the growing burden of cardiovascular disease in the developing world

Cardiovascular disease (CVD) has become the number-one cause of death in the developing world. This epidemic has the potential to place a large social and economic burden on developing countries, where CVD tends to strike those in their prime working years. Since resources for managing CVD are limited, it is important that interventions be guided by cost-effectiveness results for low- and middle-income countries. Despite the burden, cost-effective strategies exist at the population and individual levels for reducing CVD. Integral to all personal intervention strategies is an adequate assessment of the underlying risk of disease.

Addison's disease and the regulation of potassium: the role of insulin and aldosterone

It is proposed that insulin has a cardinal role in the regulation of serum potassium levels in man, which may be of greater importance than the effect of insulin on glucose metabolism. Although the first described action of insulin was on glucose transport, it is a hormone with many functions some of which may operate in a metabolic hierarchy depending on the relative importance of the action required. Insulin also promotes the transport of potassium ions from the extracellular space to the intracellular space and it is suggested that there are occasions where this action may take place at the expense of glucose regulation. In metabolic terms, tight control of serum potassium is of greater importance than precise control of serum glucose, because quite small variations in serum potassium may cause death whereas wide variations in serum glucose may be tolerated. Serum potassium levels generally remain very stable despite large daily variations in potassium intake. It follows that potassium control mechanisms must be of outstanding efficiency as serious disturbances of potassium balance are relatively uncommon. 'Nature makes experiments on Man': shadowy but important physiological mechanisms that may almost be taken for granted in normal health are often brightly illuminated by unusual pathological conditions. This paper describes two remarkable patients who presented with extreme hyperkalaemia. This condition was the result of simultaneous insulin and aldosterone deficiency occurring because of concomitant diabetes and Addison's disease. Other medical conditions with disturbances in aldosterone, insulin and potassium control will be referred to in support of the hypothesis that insulin secretion is central to potassium regulation. This hypothesis explains the secondary disturbances in glucose metabolism that occurs in clinical situations where the primary problem is perturbation of potassium regulation.