Effects of losartan versus hydrochlorothiazide on indices of endothelial damage/dysfunction, angiogenesis and tissue factor in essential hypertension

Improvements in markers of inflammation and coagulation potential following a 5-day high-fat diet rich in cottonseed oil vs. Olive oil in healthy males

Low-grade inflammation is believed to be a risk factor for chronic diseases and is nutritionally responsive. Cottonseed oil (CSO), which is rich in n-6 polyunsaturated fats, has been shown to lower cholesterol and other chronic disease risk factors. The purpose of this secondary analysis was to determine the comparative responses of markers of inflammation and coagulation potential of healthy adult males consuming diets rich in CSO vs. olive oil (OO).

METHODS

Fifteen normal-weight males, ages 21.7 ± 2.58y, completed a randomized crossover trial. Each intervention consisted of a 3-day lead-in diet and a 5-day outpatient, controlled feeding intervention (CSO or OO). There was a 2 to 4-week washout period between interventions. The 5-day intervention diets were 35 % carbohydrate, 15 % protein, and 50 % fat, enriched with either CSO or OO (44 % of total energy from oil). At pre- and post- diet intervention visits, a fasting blood draw was collected for analysis of markers of inflammation (Tumor Necrosis Factor Alpha (TNF-α), Interleukin-6 (IL-6), C-Reactive Protein (CRP)) and coagulation potential (Tissue Factor (TF), Plasminogen Activator Inhibitor-1 (PAI-1)).

RESULTS

The CSO-enriched diets reduced TNF-α (CSO: -0.12 ± 0.02 pg/ml, OO: -0.01 ± 0.05 pg/ml; p < 0.01) and TF (CSO: -0.59 ± 0.68 pg/ml, OO: 1.13 ± 0.83 pg/ml; p = 0.02) compared to OO diets. There were no differences in IL-6, CRP, or PAI-1 between diets.

CONCLUSION

A 5-day, CSO-enriched diet may be sufficient to reduce inflammation and coagulation potential compared to OO-enriched diets in a healthy male population which could have implications in chronic disease prevention.

Comparative Efficacy of Antihypertensive Agents in Flow-Mediated Vasodilation of Patients with Hypertension: Network Meta-Analysis of Randomized Controlled Trial

Hypertension induces both structural and functional changes in blood vessels, thereby increasing endothelial dysfunction, which in turn, contributes to an increase in blood pressure. A popular and widely used noninvasive tool, flow-mediated dilation (FMD), is used to examine peripheral artery endothelium-dependent dilation. This study aimed to compare the efficacies of different classes of antihypertensive agents based on their effects on FMD. PubMed, Embase, and Cochrane Library were queried till November 1, 2020. Comparative studies on the efficacies of two or more antihypertensive agents or placebos for hypertensive patients were included. The outcomes were variations in mean systolic and diastolic blood pressure. Two reviewers independently reviewed and filtered the literature and extracted the data; the Cochrane “risk of bias” method was used to evaluate the methodological quality of the randomized controlled trials. A network meta-analysis was performed using Stata 15.0 software with a total of 49 studies. Subgroup analysis based on age and duration of treatments was performed. As compared to the placebo group, patients receiving the antihypertensive drugs exhibited significantly enhanced FMD (ARB + CCB: 4.01%, 95% CI, 0.92–7.11%, p < 0.001; ACEI + ARB: 2.81%, 95% CI, 1.19–4.43%, p < 0.001; ACEI: 2.55%, 95% CI, 1.34–3.77%, p < 0.001; ARB: 2.22%, 95% CI, 1.05–3.38%, p < 0.001; β-blocker: 2.23%, 95% CI, 0.93–3.52%, p < 0.001). In the SUCRA curve for network meta-analysis, the combination of CCB and ARB was found to be the most effective in increasing FMD (SUCRA = 89.0%), followed by ACEI monotherapy (SUCRA = 74.2%). ARB combined with CCB was superior in improving the endothelial function measured as the FMD; ACEI monotherapy was the most effective treatment among the antihypertension medications. There were no significant differences between antihypertensive drug-based monotherapies.

A New Therapeutic Candidate for Cardiovascular Diseases: Berberine

Cardiovascular diseases (CVD) are the leading cause of death in the world. However, due to the limited effectiveness and potential adverse effects of current treatments, the long-term prognosis of CVD patients is still discouraging. In recent years, several studies have found that berberine (BBR) has broad application prospects in the prevention and treatment of CVD. Due to its effectiveness and safety for gastroenteritis and diarrhea caused by bacterial infections, BBR has been widely used in China and other Asian countries since the middle of the last century. The development of pharmacology also provides evidence for the multi-targets of BBR in treating CVD. Researches on CVD, such as arrhythmia, atherosclerosis, dyslipidemia, hypertension, ischemic heart disease, myocarditis and cardiomyopathy, heart failure, etc., revealed the cardiovascular protective mechanisms of BBR. This review systematically summarizes the pharmacological research progress of BBR in the treatment of CVD in recent years, confirming that BBR is a promising therapeutic option for CVD.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

Calcium Channel Blockers in Restoration of Endothelial Function: Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Clinical evaluation of the Endothelial Function (EF) is becoming an essential step in the quality assessment of cardiovascular risk prevention and rational pharmacotherapy of cardiovascular disorders. The existing pieces of evidence suggested that Calcium Channel Blockers (CCB) can induce positive effects on impaired EF.

OBJECTIVE

To evaluate the effects of CCB on EF, we performed a meta-analysis of available data from randomized and placebo-controlled or other treatment-controlled clinical studies encompassing effects of CCB on EF, as measured by Flow-Mediated Dilation (FMD) of the brachial artery.

METHODS

The relevant clinical studies were searched by systematic exploration of the appropriate databases until November 30, 2017. A random-effect model was conducted. The primary outcome was the percentage change in FMD between the baseline and the final levels in response to investigated drugs.

RESULTS

Fifteen randomized clinical studies with 33 arms were identified. CCB improved FMD more pronounced than thiazide diuretics - TD (3 studies, 157 participants, WMD=2.08%, 95% CI=0.35-3.80%; P=0.02). Oppositely, ACE Inhibitors (ACEI) and Angiotensin Receptor Blockers (ARB) notably improved FMD if compared to CCB (CCB vs. ACEI: 5 studies, 533 participants, WMD = -1.62%, 95% CI = -2.74% to -0.50%; P=0.005; and CCB vs. ARB: 9 studies, 669 participants, WMD = -1.52%, 95% CI = -2.22% to -0.81%; P=0.0001). CCB effects on EF were similar to those evoked by beta blockers or placebo.

CONCLUSION

CCB improved EF to a more prominent extent only if paralleled to TD, while inversely; ACEI and ARB were more effective in augmenting FMD.

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Chlorthalidone Improves Endothelial-Mediated Vascular Responses in Hypertension Complicated by Nondiabetic Metabolic Syndrome

Background: The study was conducted to evaluate the vascular effects of chlorthalidone, a distal tubule-acting natriuretic agent, in hypertensive patients with nondiabetic metabolic syndrome, an insulin-resistant condition characterized by endothelial dysfunction and high risk for diabetes mellitus development.

Methods: Thirteen untreated hypertensive patients with Adult Treatment Panel-III-defined nondiabetic metabolic syndrome were assigned to 3-month treatment with chlorthalidone. The end-points were baseline and post-treatment evaluation of (1) forearm blood flow (strain-gauge plethysmography) responses to graded intra-arterial acetylcholine infusion to test endothelial-mediated vasomotor function, with sodium nitroprusside as a control for endothelium-independent vasodilatation; (2) minimum forearm vascular resistance, the ratio of mean blood pressure and maximal blood flow in response to 13-minute arterial occlusion, as a hemodynamic correlate of arteriolar structure; and (3) transcapillary albumin escape rate (the 1-hour decay rate of 125I-albumin, 6-8 μC ev) as a measure of systemic capillary permeability. Additional measurements included baseline and posttreatment lipids, fasting, and postload glucose and insulin as well as the homeostasis model assessment, an index of insulin sensitivity.

Results: Chlorthalidone reduced blood pressure, augmented acetylcholine-mediated vasodilatation, decreased minimum forearm resistance, and slowed the transcapillary albumin escape rate. Metabolic parameters did not change significantly except for an increase in low-density lipoprotein cholesterol levels.

Conclusions: Chlorthalidone improved endothelial function, reversed abnormal arteriolar structure, and slowed albumin permeation in hypertensive patients with nondiabetic metabolic syndrome.

Effect of Angiotensin Receptor Blockers on Flow-Mediated Vasodilation: A Meta-Analysis of Randomized Controlled Trials

Background: In a meta-analysis, we investigated the effects of angiotensin receptor blockers (ARBs) in comparison to placebo or other classes of antihypertensive drugs on endothelial function, which was measured by brachial flow-mediated vasodilation (FMD). Methods: We searched for randomized controlled trials that compared ARBs with placebo or other classes of antihypertensive drugs in improving FMD. A random-effect model was used to compute pooled estimates. Results: In 13 trials (n = 529), ARBs were more efficacious in improving brachial FMD than placebo [pooled weighted mean change difference (WMD) 1.34%, 95% CI, 0.93-1.75%, p < 0.001]. In 15 trials (n = 918), treatment with ARBs had a significant effect on brachial FMD when compared with other antihypertensive drugs (pooled WMD 0.59%, 95% CI, 0.20-0.98%, p = 0.003 with significant heterogeneity). ARBs were also more efficacious in improving brachial FMD than calcium channel blockers (CCBs; pooled WMD 1.61%, 95% CI, 0.72-2.49%, p < 0.001) but not the other classes of drugs (p ≥ 0.072). Conclusions: This meta-analysis shows that ARBs improve brachial FMD, a marker of endothelial function, and that they are superior to placebo and CCBs. There was no significant difference in the effect on brachial FMD between ARBs and the other antihypertensive drugs.

Angiotensin II receptor blockers improve peripheral endothelial function: a meta-analysis of randomized controlled trials

OBJECTIVE(S)

Several studies have assessed the effect of angiotensin II receptor blockers (ARBs) on peripheral endothelial dysfunction as measured by flow-mediated vasodilatation (FMD), a widely-used indicator for endothelial function. We conducted a meta-analysis to investigate the effect in comparison to placebo or no treatment and other antihypertensives.

METHODS

MEDLINE, Cochrane library and EMBASE were searched to September 2013 for randomized controlled trials (RCTs) that assessed the effect of ARBs versus placebo or no treatment and other antihypertensives (angiotensin-converting enzyme inhibitors (ACEIs), calcium channel blockers (CCBs), β-blockers, diuretics) by forearm FMD. Furthermore, we also use meta-regression to analyze the relationship between the endothelial function and the duration of ARBs treatments.

RESULTS

In 11 trials including 590 patients, ARBs (n = 315) significantly improved FMD (1.36%, 95% confidence internal [CI]:1.28 to 1.44) versus placebo or no treatment (n = 275). In 16 trials that included 1028 patients, ARBs (n = 486) had a significant effect (0.59%, 95% CI: 0.25 to 0.94) on FMD when compared with other antihypertensives (n = 542). In 8 trials, ARBs (n = 174) had no significant effect (-0.14%, 95% CI: -0.32 to 0.03) compared with ACEI (n = 173). Compared with others, the benefits of ARBs, respectively, were 1.67% (95% CI: 0.65 to 0.93) in 7 trials with CCBs, 0.79% (95% CI: 0.42 to 1.01) with β-blockers in 3 trials and 0.9% (95% CI: 0.77 to 1.03) with diuretics in 3 trials. Importantly, we found ARBs were less effective in a long time span (95% CI: -1.990 to -0.622) than the first 6 months (95% CI: -0.484 to 0.360).

CONCLUSIONS

This study shows that ARBs improve peripheral endothelial function and are superior to CCBs, β-blockers and diuretics. However, the effect couldn't be maintained for a long time. In addition, there was no significant difference between ARBs and ACEI.

Hypertension update and cardiovascular risk reduction in physically active individuals and athletes

Hypertension is a prevalent disease worldwide. Its inadequate treatment leads to major cardiovascular complications, such as myocardial infarction, stroke, and heart failure. These conditions decrease life expectancy and are a substantial cost burden to health care systems. Physically active individuals and professional athletes are not risk free for developing this condition. Although the percentage of persons affected is substantially lower than the general population, these individuals still need to be thoroughly evaluated and blood pressure targets monitored to allow safe competitive sports participation. Regarding treatment, lifestyle modification measures should be routinely emphasized to athletes and active individuals with the same importance as for the general population. Medication treatment can be complicated because of restrictions by athletic organizations and possible limitations on maximal exercise performance. In addition, the choice of an antihypertensive drug should be made with consideration for salt and water losses that routinely occur in athletes, as well as preservation of exercise performance and endothelial function. First-line therapies for athletes and physically active individuals may be different from the general population. Some authorities believe that blocking the renin-angiotensin system with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) is more beneficial compared with diuretics because of ACE inhibitors and ARBs being able to avoid salt and water losses. Dihydropyridine calcium channel blockers (CCBs) are another reasonable choice. Despite effects on heart rate, nondihydropyridine CCBs do not appear to impair exercise performance. beta-Blockers are not used as a first-line therapy in athletes because of effects on exercise and prohibition by the National Collegiate Athletic Association and World Anti-Doping Agency in certain sports. In this article, we address the evidence on hypertension and its related treatments in active individuals to provide recommendations that allow the best competitive sports results and reduce cardiovascular risk.

Large and small artery endothelial function in patients with essential hypertension – Effect of ACE inhibition and beta‐blockade

Hypertension has been associated with changes in endothelial function in both large muscular arteries and small resistance arteries. We evaluated the relationship between blood flow velocity and dilatation of the brachial artery following transient forearm ischemia and acetylcholine-induced relaxation in subcutaneous small arteries and the influence of antihypertensive therapy on both in patients with essential hypertension. Thirty-one previously untreated hypertensive patients were randomized in a double-blind fashion to treatment with either the angiotensin-converting enzyme (ACE) inhibitor perindopril or the beta-blocker atenolol and compared with 17 healthy normotensive controls. Before and after 1 year of treatment, while still on active medication, flow-mediated dilatation (FMD) was measured in the brachial artery using ultrasound while relaxation to acetylcholine in small arteries was tested in vitro in a myograph. FMD correlated inversely to resting brachial artery diameter (r = -0.38, p<0.05). FMD corrected for resting diameter (FMD(corr)) was lower in patients (3.0+/-0.2%) compared with controls (4.2+/-0.3%, p<0.01). In both patients and controls, FMD(corr) was related to flow velocity in a non-linear way with FMD(corr) reaching a maximum despite increasing flow velocities, and in the patients, FMD(corr) was only reduced at high flow velocities. Furthermore, patients had a reduced acetylcholine-induced relaxation in small arteries (p = 0.04). Perindopril and atenolol reduced blood pressure to similar levels and both drugs improved FMD(corr) to a similar degree without any effects on relaxation to acetylcholine in small arteries. The present study demonstrates the role of correcting for differences in baseline diameter during measurements of FMD and a non-linear relationship between flow velocity and FMD in the brachial artery. Furthermore, the results suggest different effects of antihypertensive treatment on endothelial function in large and small arteries.

Ramipril improves oxidative stress-related vascular endothelial dysfunction in db/db mice

Endothelial dysfunction often precedes Type 2 diabetes-associated cardiovascular complications. One important cause of endothelial dysfunction is oxidative stress, which can lead to reduced nitric oxide (NO) bioavailability. In this study, we examined the effects of ramipril (an angiotensin-converting enzyme inhibitor, ACEI) on reactive oxygen species (ROS) production and endothelium-dependent vasodilation using a Type 2 diabetic (db/db) murine model. Plasma concentration of 8-isoprostane ([8-isoP]) was measured and used as an indication of the amount of ROS production. Six weeks of ramipril (10 mg/kg/day) treatment significantly reduced [8-isoP] and improved acetylcholine(ACh)-induced vasodilation in db/db mice without altering responses in wild-type (WT) mice. Responsiveness of smooth muscle cells to NO, assessed by sodium nitroprusside-induced vasodilation, was not different between db/db and WT mice regardless of ramipril or vehicle treatment. Our results suggest that ramipril specifically improved endothelium-dependent vasodilation in Type 2 diabetic mice, possibly by reducing ROS levels.

In vivo platelet activation is responsible for enhanced vascular endothelial growth factor levels in hypertensive patients

BACKGROUND

Essential hypertension may be a consequence of an abnormal regulation of vascular endothelial growth factor (VEGF). In vivo activation of platelets does result in the release of VEGF. Thus, we investigated whether VEGF production in hypertensive patients is related to in vivo platelet activation, and whether it may be modified by aspirin treatment.

METHODS

Plasma VEGF, soluble (s)P-selectin and thrombin-anti-thrombin complex (TATc) were analyzed in 80 patients with therapeutically controlled essential hypertension and 40 age and sex-matched healthy normotensive controls. The effects of a 6-month treatment with aspirin 100 mg/day on VEGF levels of 20 hypertensive patients were also studied.

RESULTS

Plasma VEGF (p<0.0001), sP-selectin (p=0.01) and TATc (p=0.02) levels were higher in hypertensives compared to controls. Multivariate analysis including age, sex, risk factors, cardiovascular disease, anti-hypertensive treatment, sP-selectin and TATc showed that only sP-selectin was an independent predictor of VEGF (beta=0.40, p<0.03). Aspirin treated hypertensives showed a significant reduction of sP-selectin (-26%, p<0.01) and VEGF (-33%, p<0.01) levels. Moreover, the reduction of plasma VEGF levels directly correlated with that of sP-selectin (Rho=0.46, p=0.04).

CONCLUSIONS

In vivo activation of platelets in hypertensive patients is responsible for enhanced circulating VEGF levels, which are significantly lowered by aspirin treatment.

Effect of losartan, compared with atenolol, on endothelial function and oxidative stress in patients with type 2 diabetes and hypertension

OBJECTIVE

It has been shown that angiotensin-converting enzyme inhibition or angiotensin receptor blockade may improve endothelial dysfunction, an early manifestation of atherosclerosis, in patients with diabetes. Whether this protective effect is mediated through blood pressure-lowering effects or other specific mechanisms such as a reduction in oxidative stress is not clear. We investigated the influence of losartan, compared with atenolol, on endothelial function and oxidative stress in patients with type 2 diabetes and hypertension.

METHODS

Thirteen patients were included in this randomized, double-blind, crossover study; they received losartan 50 mg twice daily for 4 weeks followed by atenolol 50 mg twice daily or vice versa. Concomitant medication with renin-angiotensin blocking agents or beta-blockers was withdrawn, whereas other medication remained unchanged. At baseline and after each treatment period, flow-mediated dilation of the brachial artery and oxidative stress were measured in serum samples.

RESULTS

Flow-mediated dilation was increased significantly after 4 weeks' treatment with losartan (3.4 +/- 0.44%) compared with atenolol (2.58 +/- 0.42%; P = 0.01). 8-Isoprostanes, a marker of oxidative stress, were significantly reduced in the losartan group compared with baseline (0.039 +/- 0.007 versus 0.067 +/- 0.006 ng/ml; P = 0.01), but did not differ from baseline with atenolol. Glucose, hemoglobin A1c, highly sensitive C-reactive protein, lipids and systolic blood pressure remained unaltered, whereas diastolic blood pressure tended to be lower in the atenolol group.

CONCLUSIONS

This study demonstrates that losartan significantly improved endothelial function in type 2 diabetes patients with hypertension compared with atenolol. This must be independent of the blood pressure-lowering effect of losartan and is probably caused by an antioxidative effect of the angiotensin receptor blocker.

Endothelial function and its assessment

Endothelial dysfunction is a characteristic aspect of most of the conditions associated with atherosclerosis and is commonly found as an early feature in atherothrombotic vascular disease. An appreciation of the underlying mechanisms of endothelial function, as well as dysfunction, is essential as this has critical influence on the different methods in the assessment of endothelial function and effects of various treatments on its quantification. Furthermore, endothelial dysfunction is recognised as a type of 'target organ damage' in common cardiovascular conditions (e.g., hypertension) and the area is of increasing interest for new drug development, as therapies that modulate the endothelium will have added advantages; thus, for the development of new/experimental drugs, an awareness of ways to assess the endothelium is necessary. In this review, an overview of different methods including biochemical markers, and invasive and non-invasive tools, to determine endothelial function is presented as well as their clinical relevance. Furthermore, the effects of various treatments on endothelial dysfunction and their underlying mechanisms are elucidated.