Hydrochlorothiazide abolishes the anti-atherosclerotic effect of quinapril

Circulating microparticles and central blood pressure according to antihypertensive strategy

OBJECTIVES

This prospective, randomized, open-label study aimed to compare the effects of antihypertensive treatment based on amlodipine or hydrochlorothiazide on the circulating microparticles and central blood pressure values of hypertensive patients.

METHODS

The effects of treatments on circulating microparticles were assessed during monotherapy and after the consecutive addition of valsartan and rosuvastatin followed by the withdrawal of rosuvastatin. Each treatment period lasted for 30 days. Central blood pressure and pulse wave velocity were measured at the end of each period. Endothelial, monocyte, and platelet circulating microparticles were determined by flow cytometry. Central blood pressure values and pulse wave velocity were recorded at the end of each treatment period.

RESULTS

No differences in brachial blood pressure were observed between the treatment groups throughout the study. Although similar central blood pressure values were observed during monotherapy, lower systolic and diastolic central blood pressure values and early and late blood pressure peaks were observed in the amlodipine arm after the addition of valsartan alone or combined with rosuvastatin. Hydrochlorothiazide-based therapy was associated with a lower number of endothelial microparticles throughout the study, whereas a higher number of platelet microparticles was observed after rosuvastatin withdrawal in the amlodipine arm.

CONCLUSIONS

Despite similar brachial blood pressure values between groups throughout the study, exposure to amlodipine was associated with lower central blood pressure values after combination with valsartan, indicating a beneficial interaction. Differences between circulating microparticles were modest and were mainly influenced by rosuvastatin withdrawal in the amlodipine arm.

Pathophysiological Mechanisms and Correlates of Therapeutic Pharmacological Interventions in Essential Arterial Hypertension

Treating arterial hypertension (HT) remains a hard task. The hypertensive patient is often a subject with several comorbidities and metabolic abnormalities. Clinicians everyday have to choose the right drug for the single patient among the different classes of antihypertensives. Apart from lowering blood pressure, a main therapeutic target should be that of counteracting all the possible pathophysiological mechanisms involved in HT itself and in existing/potential comorbidities. All the ancillary positive and negative effects of the administered drugs should be considered: in particular, since hypertensive patients are often glucose intolerant/diabetic, carrier of serum lipids disorder, have already developed atherosclerotic diseases and endothelial dysfunction, they should not be treated with drugs negatively interfering with these conditions but with molecules that, if possible, improve them. The main pathophysiological mechanisms and correlates of therapeutic pharmacological interventions in essential HT are reviewed here.

Phenolic compounds from sandpaper (ficus exasperata) leaf inhibits angiotensin 1 converting enzyme in high cholesterol diet fed rats

ETHNOPHARMACOLOGICAL RELEVANCE

Sandpaper [Ficus exasperata Vahl (Moraceae)] leaf has been reportedly used in folklore for the management/treatment of cardiovascular diseases with little/or no scientific basis for their action. This study sought to investigate the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in hypercholesterolemia as well as the effect of their phenolic extract on this enzyme in vitro.

MATERIALS AND METHODS

The phenolic extract was prepared, then, the inhibitory effect of the leaf extract on ACE was determined in vitro. Thereafter, the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in high cholesterol diet fed rats for 14 days was evaluated as well as some biochemical parameters.

RESULTS

The result revealed that under in vitro condition, the phenolic extract inhibited ACE (IC50=14.7µg/mL) in a dose-dependent manner (0-10µg/mL). Feeding high cholesterol diets to rats caused a significant (P<0.05) increase in the ACE activity. However, there was a significant (P<0.05) decrease in the ACE activity as a result of supplementation with the sand paper leaves. Furthermore, there was a significant (P<0.05) increase in the plasma lipid profile with a concomitant increase in malondialdehyde (MDA) content in rat liver and heart tissues. However, supplementing the diet with sandpaper leaf (either 10% or 20%) caused a significant (P<0.05) decrease in the plasma total cholesterol (TC), triglyceride (TG), very low density lipoprotein-cholesterol (VLDL-C), and low-density lipoprotein-cholesterol levels (LDL-C), and in MDA content in the tissues. Conversely, supplementation caused a significant (P<0.05) increase in plasma high-density lipoprotein-cholesterol level when compared with the control diet. Reversed phase HPLC analysis of the extract revealed Quercitrin (43.7mg/g), chlorogenic acid (42.8mg/g) and caffeic acid (33.9mg/g) as the major phenolics in the leaf.

CONCLUSION

The inhibition of ACE activity and prevention of hypercholesterolemia by sandpaper leaf could be part of the possible mechanism underlying its anti-hypertensive property which could lay credence to its use in folk medicine. However, these activities may be directly/indirectly attributed to the polyphenolics present.

Inhibition of angiotensin-1-converting enzyme activity by two varieties of ginger (Zingiber officinale) in rats fed a high cholesterol diet

Angiotensin-1-converting enzyme (ACE) inhibitors are widely used in the treatment of cardiovascular diseases. This study sought to investigate the inhibitory effect of two varieties of ginger (Zingiber officinale) commonly consumed in Nigeria on ACE activity in rats fed a high cholesterol diet. The inhibition of ACE activity of two varieties of ginger (Z. officinale) was investigated in a high cholesterol (2%) diet fed to rats for 3 days. Feeding high cholesterol diets to rats caused a significant (P<.05) increase in the ACE activity. However, there was a significant (P<.05) inhibition of ACE activity as a result of supplementation with the ginger varieties. Rats that were fed 4% white ginger had the greatest inhibitory effect as compared with a control diet. Furthermore, there was a significant (P<.05) increase in the plasma lipid profile with a concomitant increase in malondialdehyde (MDA) content in rat liver and heart tissues. However, supplementing the diet with red and white ginger (either 2% or 4%) caused a significant (P<.05) decrease in the plasma total cholesterol, triglyceride, very low density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol levels, and in MDA content in the tissues. Conversely, supplementation caused a significant (P<.05) increase in plasma high-density lipoprotein-cholesterol level when compared with the control diet. Nevertheless, rats fed 4% red ginger had the greatest reduction as compared with control diet. In conclusion, both ginger varieties exhibited anti-hypercholesterolemic properties in a high cholesterol diet fed to rats. This activity of the gingers may be attributed to its ACE inhibitory activity. However, white ginger inhibited ACE better in a high cholesterol diet fed to rats than red ginger. Therefore, both gingers could serve as good functional foods/nutraceuticals in the management/treatment of hypertension and other cardiovascular diseases.

Euterpe oleracea (açai) modifies sterol metabolism and attenuates experimentally-induced atherosclerosis

AIM

Euterpe Oleracea (açai) is a fruit from the Amazon region whose chemical composition may be beneficial for individuals with atherosclerosis. We hypothesized that consumption of Euterpe Oleracea would reduce atherosclerosis development by decreasing cholesterol absorption and synthesis.

METHODS

Male New Zealand rabbits were fed a cholesterol-enriched diet (0.5%) for 12 weeks, when they were randomized to receive Euterpe Oleracea extract (n = 15) or water (n = 12) plus a 0.05% cholesterol-enriched diet for an additional 12 weeks. Plasma phytosterols and desmosterol were determined by ultra-performance liquid chromatography and mass spectrometry. Atherosclerotic lesions were estimated by computerized planimetry and histomorphometry.

RESULTS

At sacrifice, animals treated with Euterpe Oleracea had lower levels of total cholesterol (p =0.03), non-HDL-cholesterol (p = 0.03) and triglycerides (p = 0.02) than controls. These animals had smaller atherosclerotic plaque area in their aortas (p = 0.001) and a smaller intima/media ratio (p = 0.002) than controls, without differences in plaque composition. At the end of the study, campesterol, β-sitosterol, and desmosterol plasma levels did not differ between groups; however, animals treated with Euterpe Oleracea showed lower desmosterol/campesterol (p = 0.026) and desmosterol/ β-sitosterol (p =0.006) ratios than controls.

CONCLUSIONS

Consumption of Euterpe Oleracea extract markedly improved the lipid profile and attenuated atherosclerosis. These effects were related in part to a better balance in the synthesis and absorption of sterols.

Early increase in autoantibodies against human oxidized low-density lipoprotein in hypertensive patients after blood pressure control

BACKGROUND

Oxidized lipoproteins and antioxidized low-density lipoprotein (anti-oxLDL) antibodies (Abs) have been detected in plasma in response to blood pressure (BP) elevation, suggesting the participation of the adaptive immune system. Therefore, treatment of hypertension may act on the immune response by decreasing oxidation stimuli. However, this issue has not been addressed. Thus, we have here analyzed anti-oxLDL Abs in untreated (naive) hypertensive patients shortly after initiation of antihypertensive therapeutic regimens.

METHODS

Titers of anti-oxLDL Abs were measured in subjects with recently diagnosed hypertension on stage 1 (n = 94), in primary prevention of coronary disease, with no other risk factors, and naive of antihypertensive medication at entry. Subjects were randomly assigned to receive perindopril, hydrochlorothiazide (HCTZ), or indapamide (INDA) for 12 weeks, with additional perindopril if necessary to achieve BP control. Abs against copper-oxidized LDL were measured by enzyme-linked immunosorbent assay.

RESULTS

Twelve-week antihypertensive treatment reduced both office-based and 24-h ambulatory BP measurements (P < 0.0005). The decrease in BP was accompanied by reduction in thiobarbituric acid-reactive substances (TBARS) (P < 0.05), increase in anti-oxLDL Ab titers (P < 0.005), and improvement in flow-mediated dilation (FMD) (P < 0.0005), independently of treatment. Although BP was reduced, we observed favorable changes in anti-oxLDL titers and FMD.

CONCLUSIONS

We observed that anti-oxLDL Ab titers increase after antihypertensive therapy in primary prevention when achieving BP targets. Our results are in agreement with the concept that propensity to oxidation is increased by essential hypertension and anti-oxLDL Abs may be protective and potential biomarkers for the follow-up of hypertension treatment.

Do thiazides worsen metabolic syndrome and renal disease? The pivotal roles for hyperuricemia and hypokalemia

PURPOSE OF REVIEW

The aims of this article are to review the current controversies related to the use of thiazide diuretics as first-line treatment of hypertension and to discuss the causal roles for hyperuricemia and hypokalemia on the adverse consequences of thiazide usage.

RECENT FINDINGS

Thiazides significantly reduce morbidity and mortality in hypertensive subjects. There remains, however, debate about thiazide usage as first-line treatment of hypertension. This negative impact of thiazides may be partially attributed to the ability of thiazides to exacerbate features of metabolic syndrome or increase the risk for developing diabetes. Several clinical trials suggest that thiazide-induced hyperuricemia and hypokalemia may account for some of these negative effects. Thiazide treatment is also associated with a decline of renal function in spite of a lowering blood pressure. In this review, we discuss the clinical and experimental evidence supporting a potential role of hyperuricemia and hypokalemia on the development of renal injury and worsening of the metabolic syndrome.

SUMMARY

Hyperuricemia and hypokalemia may have pivotal roles in the exacerbation of the metabolic syndrome in response to thiazides. We propose that controlling serum uric acid and serum potassium could improve thiazide efficacy and also reduce its risk for inducing metabolic syndrome or diabetes.

Irbesartan for the treatment of hypertension in patients with the metabolic syndrome: a sub analysis of the Treat to Target post authorization survey. Prospective observational, two armed study in 14,200 patients

Objectives

The metabolic syndrome is a cluster of cardiovascular risk factors leading to an increased risk for the subsequent development of diabetes and cardiovascular morbidity and mortality. Blocking the renin-angiotensin system has been shown to prevent cardiovascular disease and delay the onset of diabetes. Irbesartan is an angiotensin receptor blocker (ARB) which has been shown to possess peroxisome proliferator-activated receptor gamma (PPARγ) activating properties, and to have a favorable metabolic profile. Current discussion is whether the addition of small doses of hydrochlorothiazide changes this profile. Therefore the efficacy, safety and metabolic profile of Irbesartan either as monotherapy or in combination therapy was assessed in patients with the metabolic syndrome in a large observational cohort in primary care.

Research design and methods

Multicenter, prospective, two-armed, post authorization study over 9 months in 14,200 patients with uncontrolled hypertension with and without the metabolic syndrome (doctors' diagnosis based on the Adult Treatment Panel III criteria 2001). Blood pressure was measured sphygmomanometrically and cardiovascular risk factors making up the criteria for the metabolic syndrome were assessed.

Main outcome measures

Systolic (SBP) and diastolic (DBP) blood pressure reduction, – response, and – normalization (systolic and diastolic), changes in fasting glucose, waist circumference (abdominal obesity), serum triglycerides and HDL cholesterol as well as the proportion of patients fulfilling the criteria for the metabolic syndrome. Number and nature of adverse events (AEs).

Results

After 9 month the use of Irbesartan in monotherapy resulted in a significant reduction of blood pressure (SBP: -26.3 ± 10.1 mmHg/DBP-13.0 ± 6.6 mmHg, both p < 0.0001) in patients with the metabolic syndrome. This was accompanied by a reduction in cardiovascular risk factors: HDL cholesterol (+3.6 ± 7.2 mg/dl in men, +3.8 ± 6.5 mg/dl in women, both p < 0.0001), serum triglycerides (-28.6 ± 52.1 mg/dl, p < 0.0001), fasting blood glucose (-8.4 ± 25.1 mg/dl, p < 0.0001) and waist circumference (-2.4 ± 11.9 cm in men, -1.2 ± 14.2 in women, both p < 0.0001) were significantly improved. Irbesartan combination therapy (12.5 mg HCTZ) in patients with the metabolic syndrome: blood pressure reduction (SBP: -27.5 ± 10.1 mmHg/DBP: -14.1 ± 6.6 mmHg, both p < 0.0001), improvement in HDL cholesterol (+4.0 ± 6.8 mg/dl in men, +3.4 ± 6.8 in women, both p < 0.0001), triglycerides (-34.1 ± 52.6 mg/dl, p < 0.0001), fasting blood glucose (-10.0 ± 24.7, p < 0.0001) and waist circumference (-3.2 ± 12.7 cm in men, -1.7 ± 14.4 in women, both p < 0.0001). Tolerability was excellent: only 0.6% of patients experienced an AE.

Conclusion

There was a significant improvement in blood pressure and metabolic risk factors as a result of Irbesartan treatment. There was no evidence of a difference between monotherapy and combination therapy with regard to the cardiovascular risk profile.

Valsartan, blood pressure reduction, and C-reactive protein: primary report of the Val-MARC trial

Increased levels of high-sensitivity C-reactive protein (hsCRP) are associated with incident hypertension as well as cardiovascular events, and angiotensin II is a potent proinflammatory mediator. However, whether angiotensin receptor blockade lowers hsCRP is uncertain. We performed a randomized trial in which 1668 patients with stage 2 hypertension were treated with 160 mg valsartan or 160/12.5 mg valsartan/hydrochlorothiazide (HCTZ) once daily for 2 weeks with forced titration to 320 mg valsartan or 320/12.5 mg valsartan/HCTZ for an additional 4 weeks. After 6 weeks, systolic blood pressure (-25 versus -18 mm Hg; P<0.001) and diastolic blood pressure (-14 versus -9 mm Hg; P<0.001) were reduced to a greater degree among those allocated to valsartan/HCTZ than to valsartan monotherapy. The median change in hsCRP was -0.12 mg/L among those allocated to valsartan compared with +0.05 mg/L among those allocated to valsartan/HCTZ, a 13.3% difference (P<0.001); this difference between valsartan and valsartan/HCTZ was present in all subgroups evaluated despite the fact that blood pressure reduction was greater in the combined therapy group. No relationship was observed between hsCRP reduction and blood pressure; in all analyses, the proportion of variation in change in hsCRP with valsartan monotherapy explained by change in blood pressure was <2%. Thus, in this prospective trial, valsartan reduced hsCRP levels in a manner independent of degree of blood pressure reduction. These data raise the hypothesis that angiotensin receptor blockade may have anti-inflammatory effects in addition to blood pressure-lowering effects.

High glucose levels abolish antiatherosclerotic benefits of ACE inhibition in alloxan-induced diabetes in rabbits

Renin-angiotensin system activation is recognized to play an important role in atherosclerosis. This study aimed to verify the antiatherosclerotic effects of ACE inhibition on an experimental model of diabetes and hypercholesterolemia. Diabetes was induced in New Zealand male rabbits with a single dose of alloxan (100 mg/kg, i.v.), and, according to plasma glucose levels obtained after 1 week, the animals were divided into 2 groups (> or =250 mg/dL or <250 mg/dL). Each group was randomly assigned to receive or not quinapril (30 mg/d) added to a 0.5% cholesterol-enriched diet. Animals with high glucose levels at 1 week and that remained high after 12 weeks presented higher triglyceride levels (P < 0.02 versus basal). Those initially hyperglycemic but presenting <250 mg/dL glucose at the end of study formed an additional group. Plasma ACE activity was lower in quinapril-treated animals (P < 0.01 versus untreated groups). However, aorta intima/media ratio and intima area were lower only in the subgroups of quinapril-treated animals with low glucose levels (P < 0.05). Our results support the hypothesis that high plasma glucose may abolish the antiatherosclerotic effect of ACE inhibitors.