Lowering of Elevated Ambulatory Blood Pressure by HMG-CoA Reductase Inhibitors

Do Statins Lower Blood Pressure?

Hypercholesterolemia is present in many patients with hypertension and adds a significant component of cardiovascular risk. The 3-hydroxy-3 methyl-glutarylcoenzyme A reductase inhibitors (statins) lower low-density lipoprotein cholesterol but also inhibit many of the structural and functional components of the arteriosclerotic process. Structural effects include reductions in vascular smooth muscle hypertrophy and proliferation, fibrin deposition, and collagen cross-linking. Among the functional effects are improvements in endothelial function, reduction in inflammatory cytokines and reactive oxygen species, and down-regulation of angiotensin II and endothelin receptors. These would be expected to reduce blood pressure in patients with hypertension; 14 studies have shown statin-induced decrease in blood pressure, but 11 studies showed no effect. Many of the studies had no placebo controls, were of short duration, or had small sample sizes, or combinations of these. Despite predictions made on the basis of the vasoprotective actions of statins, the blood-pressure-lowering effects of statins are at best modest.

Simvastatin induces a central hypotensive effect via Ras-mediated signalling to cause eNOS up-regulation

BACKGROUND AND PURPOSE

Clinical studies indicate that statins have a BP-lowering effect in hypercholesterolemic individuals with hypertension. Specifically, statins modulate BP through the up-regulation of endothelial NOS (eNOS) activation in the brain. However, the signalling mechanisms through which statins enhance eNOS activation remain unclear. Therefore, we examined the possible signalling pathways involved in statin-mediated BP regulation in the nucleus tractus solitarii (NTS).

EXPERIMENTAL APPROACH

To investigate the involvement of Ras and other signalling pathways in simvastatin-induced effects on BP, BP and renal sympathetic nerve activity (RSNA) were determined in spontaneously hypertensive rats (SHRs) before and after i.c.v. administration of simvastatin in the absence and presence of a Ras-specific inhibitor (farnesyl thiosalicylic acid, FTS), a geranylgeranyltransferase inhibitor (GGTI-2133), a PI3K inhibitor (LY294002) or a MAPK-ERK kinase (MEK) inhibitor (PD98059).

KEY RESULTS

FTS significantly attenuated the decrease in BP and increased NO evoked by simvastatin and reversed the decrease in basal RSNA induced by simvastatin. Immunoblotting and pharmacological studies showed that inhibition of Ras activity by FTS significantly abolished simvastatin-induced phosphorylation of ERK1/2, ribosomal protein S6 kinase (RSK), Akt and decreased eNOS phosphorylation. Likewise, administration of Akt and ERK1/2 signalling inhibitors, LY294002 and PD98059, attenuated the reduction in BP evoked by simvastatin. Furthermore, i.c.v. simvastatin decreased Rac1 activation and the number of ROS-positive cells in the NTS.

CONCLUSIONS AND IMPLICATIONS

Simvastatin modulates central BP control in the NTS of SHRs by increasing Ras-mediated activation of the PI3K-Akt and ERK1/2-RSK signalling pathways, which then up-regulates eNOS activation.

Blood pressure-lowering effect of simvastatin: a placebo-controlled randomized clinical trial with 24-h ambulatory blood pressure monitoring

Part of the efficacy of statins in the prevention of cardiovascular events can be attributed to their blood pressure-lowering effect, but clinical trials primarily designed to investigate this effect are scarce. In a double-blind parallel placebo-controlled clinical trial with ambulatory blood pressure (ABP) monitoring, 79 hypertensive patients were randomly assigned to 40 mg of simvastatin (n=40) or placebo (n=39) taken in the morning for 2 months. Between-group deltas of ABP change, adjusted for the corresponding baseline BP, were 2.8 mm Hg (95% CI: 0.4-5.1; P=0.02) for 24-h diastolic blood pressure (DBP), 4.2 mm Hg (95% CI: 0.1-8.4; P=0.04) for daytime systolic BP and 3.1 mm Hg (95% CI: 0.4-5.9; P=0.02) for daytime DBP. There was no effect on nighttime BP. There was an interaction between baseline cholesterol levels and treatment effect, which was restricted to patients with cholesterol above the median of the whole sample. There was no significant change in office BP. In conclusion, simvastatin lowers ABP in patients with hypertension, particularly in the presence of higher levels of cholesterol. This effect may contribute to the beneficial effects of statins in the prevention of cardiovascular disease.

Antihypertensive effects of statins: a meta-analysis of prospective controlled studies

In experimental studies, statins have been shown to lower blood pressure through increased nitric oxide bioavailability and improved arterial compliance. The clinical significance of this effect remains poorly documented. The authors performed a meta-analysis of the effect of statins on systolic blood pressure (SBP) and diastolic blood pressure (DBP) including prospective randomized, controlled trials of statin therapy. EMBASE and MEDLINE searches for studies in which patients were randomized to treatment with a statin plus standard treatment (or placebo) vs standard treatment (or placebo) were conducted. Studies that provided data on SBP and DBP values before the initiation of the treatment and at the end of the follow-up period were included. A total of 40 studies with 51 comparison groups examining 22,511 controls and 22,602 patients taking statins were examined. Mean SBP in the statin group decreased by 2.62 mm Hg (95% confidence interval [CI], -3.41 to -1.84; P<.001) and DBP by 0.94 mm Hg (95% CI, -1.31 to -0.57; P<.001). In studies including hypertensive patients, the decrease in blood pressures with statins was slightly greater (SBP, -3.07 mm Hg; 95% CI, -4.00 to -2.15 and DBP, 1.04; 95% CI, -1.47 to -0.61). Similarly, statins effectively reduced SBP in diabetic patients. In this large meta-analysis of prospective controlled studies, the authors found a small but statistically significant reduction of SBP in patients taking statins. The decrease in blood pressure may contribute to the pleiotropic effect of statins in reducing cardiovascular risk.

The antihypertensive actions of statins: modulation by salt intake

Hydroxy methyl glutaryl CoA inhibitors (statins) are the agents most frequently used to reduce elevated serum cholesterol. In addition to their cholesterol lowering effects, statins also have nonlipid lowering pleiotropic properties. These include reducing oxidative stress, renin-angiotensin and endothelin synthesis and activity, and improving nitric oxide (NO) synthesis and availability. Thus, one would predict that statins might be able to exert an antihypertensive effect. Experimental models bear out the blood pressure lowering effects but the data from clinical trials have been inconsistent perhaps due to inappropriate experimental designs, sample size, blood pressure measurement techniques etc. Moreover, although experimental models strongly suggest a role for salt intake in the potential antihypertensive responses to statins, available clinical trials fail to report salt intake in the studied populations. The statins' antihypertensive effects remain an unsettled hypothesis and calls for a large clinical trial at a wide range of doses and a controlled salt intake. Statins meanwhile remain as a excellent option to control high cholesterol and in tissue injury prevention.

Add-on-Statin Extended Release Nicotinic Acid/Laropiprant but Not the Switch to High-Dose Rosuvastatin Lowers Blood Pressure: An Open-Label Randomized Study

Introduction. Nicotinic acid (NA) and statins have been associated with reductions in blood pressure (BP). Patients and Methods. We recruited 68 normotensive and hypertensive dyslipidemic patients who were treated with a conventional statin dose and had not achieved lipid targets. Patients were randomized to switch to high-dose rosuvastatin (40 mg/day) or to add-on current statin treatment with extended release (ER) NA/laropiprant (1000/20 mg/day for the first 4 weeks followed by 2000/40 mg/day for the next 8 weeks) for 3 months. Results. Switching to rosuvastatin 40 mg/day was not associated with significant BP alterations. In contrast, the addition of ER-NA/laropiprant to current statin treatment resulted in a 7% reduction of systolic BP (from 134 ± 12 to 125 ± 10 mmHg, P < .001 versus baseline and P = .01 versus rosuvastatin group) and a 5% reduction of diastolic BP (from 81 ± 9 to 77 ± 6 mmHg, P = .009 versus baseline and P = .01 versus rosuvastatin group). These reductions were significant only in the subgroup of hypertensives and were independent of the hypolipidemic effects of ER-NA/laropiprant. Conclusions. Contrary to the switch to high-dose rosuvastatin, the addition of ER-NA/laropiprant to statin treatment was associated with significant reductions in both systolic and diastolic BP.

Statin therapy in metabolic syndrome and hypertension post-JUPITER: what is the value of CRP?

Much evidence supports a pivotal role for inflammation in atherosclerosis. C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a cardiovascular risk marker and may also promote atherogenesis. CRP levels are increased in metabolic syndrome and hypertension and confer increased risk of cardiovascular events in patients in these subgroups. Statins have been shown to lower low-density lipoproteins and CRP independently, and reduce cardiovascular events in subjects with and without metabolic syndrome and hypertension. In this review, we focus on the results from the primary prevention statin trial, Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), which showed reductions in LDL, CRP, and cardiovascular events. Post-JUPITER, the new guidelines will now need to consider recommending high-sensitivity CRP testing to intermediate-risk metabolic syndrome patients and those with hypertension and intermediate risk so that we can better identify candidates at greater risk and reduce cardiovascular burden in these subjects with statin therapy.

Protection Against Nephropathy in Diabetes with Atorvastatin (PANDA): a randomized double-blind placebo-controlled trial of high- vs. low-dose atorvastatin(1)

AIMS

To compare the renal effects of low- vs. high-dose atorvastatin in patients with Type 2 diabetes mellitus and optimally managed early renal disease.

METHODS

We compared the 2-year progression of nephropathy in a double-blind randomized controlled trial of atorvastatin 80 mg/day (n = 60) vs. 10 mg/day (n = 59) in patients with Type 2 diabetes with microalbuminuria or proteinuria [mean (sd): age 64 years (10 years); HbA(1c) 7.7% (1.3%), 61 mmol/mol (10 mmol/mol); blood pressure 131/73 mmHg; renin-angiotensin system blocker use > 80%; dual blockade > 67%] recruited from diabetes clinics in Greater Manchester.

RESULTS

Over (mean) 2.1 years of follow-up, the Modification of Diet in Renal Disease estimated glomerular filtration rate declined by 3 ml min(-1) 1.73 m(-2) in the combined group. The mean (95% CI) between-group difference during follow-up was not significant [2.2 ml min(-1) 1.73 m(-2) (-1.1 to 5.4 ml min(-1) 1.73: m(-2) ), P = 0.20] after adjusting for baseline differences in renal function; positive difference favours 80 mg dose. Similarly, there was no significant difference in creatinine clearance by Cockcroft and Gault [2.5 ml/min (-2.4 to 7.3 ml/min), P = 0.32]; serum creatinine/24-h urine collections [4.0 ml/min (-4.8 to 12.7 ml/min), P = 0.38]; cystatin C (P = 0.69); or 24-h urine protein or albumin excretion (P = 0.92; P = 0.93). We recorded no significant between-group differences in deaths or adverse events.

CONCLUSIONS

In patients with Type 2 diabetes with early renal disease, we found no statistical difference in renal function between those taking high- or low-dose atorvastatin over 2 years. We cannot exclude a beneficial effect of < 1.6 ml min(-1) 1.73 m(-2) year(-1) on Modification of Diet in Renal Disease estimated glomerular filtration rate, or if blood pressure management or if renin-angiotensin system blocker use had not been optimized.

Does the blood pressure-lowering effect of statins contribute to their beneficial cardiovascular effects?

Not all cardiovascular protection provided by statins is explained by their beneficial effects on lipoproteins. Old (e.g., clofibrate) and new (e.g., torcetrapib and ezetimibe) agents, with similar or more intense beneficial effect over lipoproteins, do not reproduce the beneficial effects of statins. Besides their anti-inflammatory and other pleiotropic effects, a blood pressure-lowering effect could be an additional mechanism of cardiovascular protection of statins. Large trials of statins in the primary and secondary prevention of cardiovascular disease did not report an effect on blood pressure, but the use of blood pressure-lowering agents was left to the discretion of physicians during the trial. Post hoc analyses of small trials and a meta-analysis of some of them have suggested that statins could lower systolic blood pressure by approximately 4 mmHg, particularly in patients with high blood pressure. Most studies, however, had small samples and were not blinded. Others had a cross-over or observational design. The overall view of these studies rules out a substantial blood pressure-lowering effect of statins. An effect restricted to subjects with high blood pressure could ultimately derive from the anti-inflammatory effect of statins, since higher levels of C-reactive protein are associated with higher blood pressure. An unequivocal demonstration of an antihypertensive effect of statins, however, is still lacking, and a randomized trial with enough power to evaluate blood pressure variation in a large range of blood pressure values is required to demonstrate whether statins definitely have an antihypertensive effect.

Prospective evaluation of the effect of statins on blood pressure control in hypertensive patients in clinical practice

BACKGROUND AND AIM

Some clinical evidence supports a statin antihypertensive effect. Our aim is to evaluate the statin effect on blood pressure control in hypertensive patients in the setting of clinical practice, and the role of some predetermined individual patient characteristics (age, gender, baseline BP levels, pre-treatment LDL-C levels) on the supposed statin BP lowering effect.

METHODS AND RESULTS

Two hundred and fifty-four hypertensive patients with hypercholesterolemia were enrolled in the Ambulatory service of the Hypertension Research Unit of Bologna University Hospital. After 2-4 weeks of a run-in period patients were allocated to statin treatment and followed-up for 24 weeks. The blood pressure response to statins was compared in several subgroups of patients according to age, gender, baseline BP and pre-treatment cholesterolemia. In the overall study population, the use of statins was associated with a significant reduction in systolic (-7.6+/-4 mmHg, p<0.05) and diastolic blood pressures (-5.2+/-3 mmHg, p<0.05) in comparison to baseline. The blood pressure decrease was more pronounced in patients younger than 65 years (p<0.05), with higher baseline systolic blood pressure (p<0.005), and in those with higher cholesterolemia before statins (p<0.05).

CONCLUSIONS

Our study suggests a BP-lowering effect of statins, consistent with some other literature. Some parameters like age, baseline systolic blood pressure and cholesterolemia influence the antihypertensive effect of statins. The lack of consideration for these confounding factors may be one of the reasons for the conflicting results about the BP lowering effects of statins.

Statins in hypertension: are they a new class of antihypertensive agents?

High blood pressure is a very common disease in hypercholesterolemic and diabetic patients and contributes to the increase in cardiovascular risk. Inhibitors of 3OH-3methyl-glutaryl-coenzyme A reductase are the most effective and widely used cholesterol-lowering drugs. They significantly reduce the risk of cardiovascular events and death in both primary and secondary prevention of cardiovascular disease. Although the long-term benefit by statin treatment is largely attributed to their cholesterol-lowering action, increasing attention focuses on additional actions called "pleitropic effects" that might explain the cardiovascular protection seen shortly after the initiation of therapy. Very few and small studies have investigated the antihypertensive effect of statins in patients with hypertension associated with hypercholesterolemia, and the results of recently published large statin studies (albeit not designed to answer this question) have attracted the interest on this subject. Many other studies, also not specifically aimed at the evaluation of the statins' antihypertensive effect, have provided information concerning changes in blood pressure during treatment with statins, but severe limitations such as inadequate study design, small or very small sample size, too short of a treatment period, and modification of concomitant antihypertensive therapy have prevented finding a definitive effect on blood pressure. From the available results, it appears consistent that statins may be useful in hypertensives with high serum total cholesterol, in those whose hypertension is not well controlled with antihypertensive agents even without high serum total cholesterol, in hypertensive subjects well controlled with antihypertensives without high serum cholesterol when they have high polymerase chain reaction levels, in those who require preventive measures because of other concomitant cardiovascular risk factors, or when they require secondary prevention. Future research could further characterize the impact of statin use alone or in combination with antihypertensive agents to delay the development of Stage 1 hypertension in prehypertension.

3-Hydroxymethyl coenzyme A reductase inhibition attenuates spontaneous smooth muscle tone via RhoA/ROCK pathway regulated by RhoA prenylation

RhoA prenylation may play an important step in the translocation of RhoA in the basal internal anal sphincter (IAS) smooth muscle tone. Statins inhibit downstream posttranslational RhoA prenylation by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibition (HMGCRI). The role of statins in relation to RhoA prenylation in the pathophysiology of the spontaneously tonic smooth muscle has not been investigated. In the present studies, we determined the effect of classical HMGCRI simvastatin on the basal IAS tone and RhoA prenylation and in the levels of RhoA/Rho kinase (ROCK) in the cytosolic vs. membrane fractions of the smooth muscle. Simvastatin produced concentration-dependent decrease in the IAS tone (via direct actions at the smooth muscle cells). The decrease in the IAS tone by simvastatin was associated with the decrease in the prenylation of RhoA, as well as RhoA/ROCK in the membrane fractions of the IAS, in the basal state. The inhibitory effects of the HMGCRI were completely reversible by geranylgeranyltransferase substrate geranylgeranyl pyrophosphate. Relaxation of the IAS smooth muscle via HMGCRI simvastatin is mediated via the downstream decrease in the levels of RhoA prenylation and ROCK activity. Studies support the concept that RhoA prenylation leading to RhoA/ROCK translocation followed by activation is important for the basal tone in the IAS. Data suggest that the role of HMG-CoA reductase may go beyond cholesterol biosynthesis, such as the regulation of the smooth muscle tone. The studies have important implications in the pathophysiological mechanisms and in the novel therapeutic approaches for anorectal motility disorders.

Current role of statins in the treatment of essential hypertension

IMPORTANCE OF THE FIELD

Hypertension and hyperlipidemia often co-exist and seem to be interrelated through common pathophysiological pathways. Drugs employing beneficial effects in both conditions could be advantageous in a concerted effective management of patients at high cardiovascular risk. Statins are known to enhance cardiovascular protection beyond their lipid-lowering capacity.

AREAS COVERED IN THIS REVIEW

MEDLINE was searched, up to January 2010, for studies assessing the effect of statin treatment on blood pressure control in various populations or animal models of hypertension. The potential mechanisms implicated in the putative antihypertensive action of statins are also reviewed.

WHAT THE READER WILL GAIN

To learn about the role of statins as potential antihypertensive drugs in various populations. Clinical advice for the use of statins either as monotherapy or in combination with antihypertensive drugs in high-risk populations is also provided.

TAKE HOME MESSAGE

Statins may exert a mild, but clinically relevant, antihypertensive effect which is probably mediated by mechanisms that are independent of their lipid-lowering effects. Patients with high BP levels at baseline as well as those treated with ACE inhibitors and calcium channel blockers are expected to benefit more in this regard.

Role and significance of statins in the treatment of hypertensive patients

BACKGROUND

Statins are the first-line drug therapy in the treatment of hypercholesterolemia. The beneficial clinical impact of statins on the cardiovascular system results not only from their lipid-lowering action but also from other effects. Recently, it has been suggested that statins can reduce blood pressure, especially in hypertensive patients.

AIM

The role of the hypotensive action of statins and other mechanisms which reduce cardiovascular risk in hypertensive patients are discussed in this review.

METHODS

Electronic databases searched were [MEDLINE (1966 - February 2009), EMBASE and SCOPUS (1965 - February 2009), DARE (1966 -- February 2009)]. Additionally, abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. The main data search terms were: blood pressure, hypertension, hypercholesterolemia and statins.

FINDINGS

At present, it is difficult to unequivocally assess the impact of statins on blood pressure. However, according to most authors, the impact of statins on the decrease in BP is slight, but significant, especially among patients with hypertension.

Regular thermal therapy may promote insulin sensitivity while boosting expression of endothelial nitric oxide synthase--effects comparable to those of exercise training

Regular thermal therapy, using saunas or hot baths, has the potential to improve impaired insulin sensitivity and boost endothelial expression of the "constitutive" isoform of nitric oxide synthase--effects, analogous to those of aerobic training that should promote vascular health. Previous clinical reports suggest that hot tubs may be beneficial for diabetic control, and that sauna therapy can decrease blood pressure in essential hypertension and provide symptomatic benefit in congestive heart failure. For those who lack ready access to a sauna or communal hot tub, regular hot baths at home may suffice as practical thermal therapy. Thermal therapy might be viewed as an alternative to exercise training in patients too physically impaired for significant aerobic activity.

Reduction in blood pressure with statins: results from the UCSD Statin Study, a randomized trial

BACKGROUND

Some studies have suggested reductions in blood pressure (BP)with statin treatment, particularly in persons with hypertension. Randomized trial evidence is limited.

METHODS

We performed a randomized, double-blind, placebo-controlled trial with equal allocation to simvastatin, 20 mg; pravastatin sodium,40 mg; or placebo for 6 months. Nine hundred seventy-three men and women without known cardiovascular disease or diabetes mellitus, with low-density lipoprotein cholesterol screening levels of 115 to 190 mg/dL, had assessment of systolic and diastolic BP (SBP and DBP, respectively). Blood pressure values were compared for placebo vs statins by intention-to-treat (ITT) analysis. Additional analyses were performed that (1) were confined to subjects with neither high baseline BP (SBP>140 mm Hg or DBP>90 mm Hg) nor receiving BP medications, to exclude groups in whom BP medications or medication changes may have influenced results, and (2) separately evaluated simvastatin and pravastatin (vs placebo). The time course of BP changes after statin initiation and the effect of stopping statins on BP were examined.

RESULTS

Statins modestly but significantly reduced BP relative to placebo,by 2.2 mm Hg for SBP (P=.02) and 2.4 mm Hg for DBP (P<.001) in ITT analysis. Blood pressure reductions ranged from 2.4 to 2.8 mm Hg for both SBP and DBP with both simvastatin and pravastatin, in those subjects with full follow-up, and without potential for influence by BP medications (ie, neither receiving nor meriting BP medications).

CONCLUSIONS

Reductions in SBP and DBP occurred with hydrophilic and lipophilic statins and extended to normotensive subjects. These modest effects may contribute to the reduced risk of stroke and cardiovascular events reported on statins. Trial Registration clinicaltrials.gov Identifier: NCT00330980.

Fluvastatin decreases cardiac fibrosis possibly through regulation of TGF-beta(1)/Smad 7 expression in the spontaneously hypertensive rats

Statins ameliorate myocardial fibrosis after myocardial infarction. We designed this study to determine whether fluvastatin reduced hypertension-induced myocardial hypertrophy and fibrosis and whether these fluvastatin effects involved transforming growth factor beta1 (TGF-beta1) and Smad 7, factors known to play a role in the myocardial hypertrophy and fibrosis. We randomized 14 week old spontaneously hypertensive rats (SHRs) to receiving vehicle or 5-20 mg/kg/day fluvastatin for 8 weeks. Wistar Kyoto (WKY) rats receiving vehicle or 10 mg/kg/day fluvastatin were also studied. SHRs had an increased blood pressure, left ventricular hypertrophy and fibrosis compared with WKY rats. SHRs also had an elevated TGF-beta1 expression and a decreased Smad 7 expression. These changes in SHRs were dose-dependently attenuated by fluvastatin. For example, the hydroxyproline content was 3.2+/-0.1, 4.0+/-0.1 and 3.5+/-0.1 microg/mg heart and the Smad 7 protein expression was 5.1+/-0.6, 1.0+/-0.1 and 4.1+/-0.7 arbitrary units for WKY rats, SHRs and SHRs receiving 20 mg/kg/day fluvastatin, respectively. The hydroxyproline content in the SHRs treated with or without fluvastatin was positively correlated with the left ventricular mass index, systolic blood pressure and the amount of TGF-beta1 proteins and negatively correlated with the Smad 7 expression level. The left ventricular mass index was positively correlated with the systolic blood pressure. Fluvastatin did not alter the blood pressure, left ventricular mass index and collagen content of WKY rats. These results suggest that fluvastatin reduces hypertension-induced myocardial hypertrophy and fibrosis. These effects may involve an increased expression of Smad 7 and a decreased expression of TFG-beta1. Our results call for clinical studies to evaluate these fluvastatin effects in hypertensive patients.

Are statins effective for simultaneously treating dyslipidemias and hypertension?

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are unequivocally useful for lowering cholesterol levels in patients with dyslipidemias characterized by elevations in total and/or low-density lipoprotein cholesterol. The beneficial effects of statins to lower serum cholesterol translate into significant reductions in cardiovascular morbidity and mortality. In addition to lowering cholesterol levels, statins have other biological effects relevant to cardiovascular homeostasis including anti-inflammatory actions and downregulation of angiotensin type 1 receptor expression that contribute to improvements in endothelial function and arterial compliance. Since endothelial dysfunction and reduced arterial compliance are important pathophysiological determinants of essential hypertension, these actions of statins raise the possibility that statin therapy may be useful for simultaneously treating dyslipidemias and hypertension. However, it has been unclear whether statins are effective in lowering blood pressure. This controversy stems from a variety of methodological limitations including inadequate sample size, confounding effects of antihypertensive drugs, differences in blood pressure measurement techniques, and differences in patient populations. However, based on published results from both small clinical studies and large randomized clinical trials, statins modestly lower blood pressure in patients with high, but not normal, blood pressure, regardless of cholesterol level.

Statins and blood pressure: is there an effect or not?

In addition to the lipid-lowering effects of statins, several basic and clinical studies in recent years have examined the effects of these agents on other cardiovascular parameters. Some of these studies investigated the general impact of a statin on blood pressure (BP) among various other factors, while others were specifically designed to determine this effect. Data from animal studies are conflicting but the majority of human studies in the field report a beneficial effect, and most available statin compounds are reported to lower BP levels. Recent clinical studies using ambulatory BP measurements support these findings. Although the exact actions of statins involved in this effect are unknown, several possible mechanisms can be hypothesized. This review summarizes existing data on the effect of statins on BP, aiming to give an overview of the current knowledge and to provide perspectives for future research in the field.

Analysis of antihypertensive effects of statins

Hypertension and hyperlipidemia, two powerful risk factors of cardiovascular disease (CVD), often coexist. Therefore, treatment should consider the beneficial properties of drugs used to treat either condition. Statins, the mainstay of lipid-lowering therapy, result in a significant clinical benefit both in primary and secondary CVD prevention. In addition to their hypolipidemic capacity, other properties may contribute to statin-induced benefits. Clinical and experimental evidence indicates that statins may modulate blood pressure (BP). The mechanisms by which statins reduce BP seem to be largely independent of their lipid effects. Although small, reductions in BP are possibly clinically relevant. Large landmark studies confirm that statins can reduce CVD risk in hypertensive patients. These findings suggest that statins could be prescribed as an adjunct in treating hypertension with dyslipidemia or even in patients with "normal" cholesterol levels. Whether the effect of statins on BP is accompanied by an additional decrease in clinical outcomes needs to be investigated in long-term, large-scale trials.

Effects of Pravastatin Treatment on Blood Pressure Regulation after Renal Transplantation

BACKGROUND/AIM

Hypertension is one of the main cardiovascular risk factors and has an impact also on long-term kidney graft survival. In addition to their lipid-lowering properties, it was shown that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors also have a blood pressure lowering effect. We examined whether treatment with a statin interferes with blood pressure regulation and antihypertensive treatment after renal transplantation.

METHODS

74 patients were treated with initially 20 mg of pravastatin daily immediately after kidney transplantation. This group was compared to a matched cohort of 76 patients without statin treatment. All patients received standard immunosuppressive triple therapy with ciclosporin A microemulsion together with an antiproliferative agent and prednisolone. Primary objective of this analysis was systolic and diastolic blood pressure regulation with and without pravastatin. Furthermore, graft function expressed as creatinine clearance and proteinuria, immunosuppressive regimen, and incidence of cardiovascular events and graft loss were recorded for 48 months.

RESULTS

The blood pressure regulation was comparable in both groups; however, to achieve this, significantly more antihypertensive drugs had to be used in the statin-treated patients as compared with the controls (2.9 vs. 2.2 agents at 48 months). A slightly higher ciclosporin A exposure of the statin-treated patients could have contributed to this observation. The graft function after 4 years was comparable between the groups (creatinine clearance 56.9 vs. 57.0 ml/min), and a trend of reduced proteinuria could be demonstrated after 4 years of statin treatment (0.4 vs. 0.9 g/day). The low-density lipoprotein cholesterol levels decreased as expected during treatment (3.1 vs. 3.7 mmol/l at 48 months), but the recommended target levels for patients with a high cardiovascular risk have not been reached. A trend towards lower incidences of acute rejection, chronic allograft nephropathy, and graft loss was noted in the statin-treated group. Adverse effects of statin treatment have not been observed.

CONCLUSION

Treatment with pravastatin at low to average dosages does not result in improved blood pressure regulation after kidney transplantation.

Effects of pravastatin on ventricular remodeling by activation of myocardial KATP channels in infarcted rats: role of 70-kDa S6 kinase

Reactive cardiomyocyte hypertrophy after myocardial infarction is an important risk factor for arrhythmias. Myocardial ATP-sensitive potassium (K(ATP)) channels have been implicated in attenuating cardiac hypertrophy by inhibition of 70-kDa S6 kinase. We investigated the effect of pravastatin on ventricular hypertrophy during remodeling after myocardial infarction and whether the attenuated hypertrophic effect was via activation of myocardial K(ATP) channels. Twenty-four hours after ligation of the anterior descending artery, male Wistar rats were randomized to either vehicle, nicorandil (an agonist of K(ATP) channels), pravastatin, glibenclamide (an antagonist of K(ATP) channels), or a combination of nicorandil and glibenclamide or pravastatin and glibenclamide for 4 weeks. Infarct size and mortality were similar among the infarcted groups. Cardiomyocyte sizes isolated by enzymatic dissociation after infarction significantly increased at the border zone in vehicle-treated infarcted rats compared with sham-operated rats. Rats in the nicorandil- and pravastatin-treated groups significantly attenuated cardiomyocyte hypertrophy, as compared with the vehicle-treated group. Arrhythmic scores during programmed stimulation mirrored those of cardiomyocyte hypertrophy. Increased 70-kDa S6 kinase mRNA expression in cardiac remodeling was confirmed by reverse transcription-polymerase chain reaction, consistent with the results of immunohistochemistry and Western blot for the phosphorylation of 70-kDa S6 kinase. Nicorandil-induced effects were abolished by administering glibenclamide. Similarly, the beneficial effects of pravastatin were abolished by administering glibenclamide, implicating K(ATP) channels as the relevant target. Activation of K(ATP) channels by pravastatin administration can attenuate ventricular remodeling through a S6 kinase-dependent pathway after infarction.

Statins: another class of antihypertensive agents?

The assessment of global cardiovascular risk is an essential step in the management of atherosclerotic disease prevention. Among the risk factors to be addressed are hypertension and hyperlipidaemia; these commonly coexist. A neutral or lipid-friendly antihypertensive agent is probably useful in the presence of lipid abnormalities. Similarly, statins have been shown to decrease cardiovascular risk in hypertensive patients. There is also experimental and clinical evidence that statins have blood pressure (BP)-lowering effects. In this review, we discuss the beneficial effects of statins on BP, and provide an overview of the underlying pathophysiology. We also consider the evidence justifying the use of statins in the management of hypertensive patients.

Statins Decrease Serotonin-Induced Contractions in Coronary Arteries of Swine in vitro

Recent evidence suggests that statins improve the status of patients with coronary artery disease not only by reducing cholesterol levels, but also by acting at the level of the endothelium-smooth muscle unit. Previous results from our laboratory showed that these drugs interact with the vascular wall by partially inhibiting calcium-dependent, agonist-induced contractions in rat aortas. To evaluate whether this effect is also extended to the coronary vasculature, we assessed the effect of statins on serotonin (5-HT) induced contractions of left and right coronary arteries of swine. Concentration-response curves for the 5-HT-induced contractions (from 0.1 nmol/l to 100 micromol/l) were calculated on rings from both coronaries in the presence and absence of either (5 micromol/l) pravastatin, mevastatin, simvastatin, lovastatin, or atorvastatin. After a 45-min incubation period, all statins significantly reduced the Emax for the 5-HT-induced contractions, ranging from 51.9 +/- 1.9% (simvastatin) to 15.9 +/- 2.0% (pravastatin) in the left coronary artery and from 48.8 +/- 2.0% (simvastatin) to 17.8 +/- 2.5% (pravastatin) in the right coronary artery. The EC50 values for the 5-HT-induced contractions were 0.150 +/- 0.005 micromol/l for the left coronary artery and 0.171 +/- 0.010 micromol/l for the right coronary artery. These values significantly changed after incubation with statins, ranging from 1.240 +/- 0.101 micromol/l (for simvastatin) to 0.081+/- 0.008 micromol/l (for pravastatin) in the left coronary artery and from 1.410 +/- 0.075 micromol/l (for simvastatin) to 0.084 +/- 0.008 micromol/l (for pravastatin) in the right coronary artery. This evidence supports the possibility that, beyond their lipid-lowering properties, statins may provide a beneficial effect in atherosclerotic patients by reducing the tone in the coronary vasculature, facilitating blood flow to the myocardium.