Endothelial dysfunction in chronic heart failure: clinical implications and therapeutic options

Relationship of arterial tonometry and exercise in patients with chronic heart failure: a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Arterial stiffness is a common characteristic in patients with chronic heart failure (CHF), and arterial tonometric technologies related to arterial stiffness are novel and effective methods and have an important value in the diagnosis and prognosis of CHF. In terms of ameliorating arterial stiffness in patients with CHF, exercise training is considered an adjuvant treatment and also an effective means in the diagnosis and judgment of prognosis. However, there are huge controversies and inconsistencies in these aspects. The objective of this meta-analysis was to systematically test the connection of arterial tonometry and exercise in patients with CHF.

METHODS

Databases, including MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, were accessed from inception to 7 March 2022. The meta-analysis was then conducted, and trial sequential analysis (TSA) was performed jointly to further verify our tests and reach more convincing conclusions by using RevMan version 5.4 software, STATA version 16.0 software, and TSA version 0.9.5.10 Beta software.

RESULTS

Eighteen articles were included, with a total of 876 participants satisfying the inclusion criteria. The pooling revealed that flow-mediated dilation (FMD) was lower in basal condition [standardized mean difference (SMD): - 2.28%, 95% confidence interval (CI) - 3.47 to - 1.08, P < 0.001] and improved significantly after exercise (SMD: 5.96%, 95% CI 2.81 to 9.05, P < 0.001) in patients with heart failure with reduced ejection fraction (HFrEF) compared with healthy participants. The high-intensity training exercise was more beneficial (SMD: 2.88%, 95% CI 1.78 to 3.97, P < 0.001) than the moderate-intensity training exercise to improve FMD in patients with CHF. For augmentation index (AIx), our study indicated no significant differences (SMD: 0.50%, 95% CI - 0.05 to 1.05, P = 0.074) in patients with heart failure with preserved ejection fraction (HFpEF) compared with healthy participants. However, other outcomes of our study were not identified after further verification using TSA, and more high-quality studies are needed to reach definitive conclusions in the future.

CONCLUSIONS

This review shows that FMD is lower in basal condition and improves significantly after exercise in patients with HFrEF compared with healthy population; high-intensity training exercise is more beneficial than moderate-intensity training exercise to improve FMD in patients with CHF; besides, there are no significant differences in AIx in patients with HFpEF compared with the healthy population. More high-quality studies on this topic are warranted.

The natural antioxidants, pomegranate extract and soy isoflavones, favourably modulate canine endothelial cell function

Cardiovascular disease, preceded by vascular endothelial dysfunction, is a prominent cause of death in dogs. L-carnitine and taurine, well known for their antioxidative capacity, beneficially affect cardiovascular disease as well as certain dog cardiomyopathies. It is well established that vascular endothelial dysfunction precedes cardiovascular disease and that “vasoprotective factors” (NO and antioxidants) prevent apoptosis, whereas “risk factors” such as oxidized LDL, hyperglycemia, and free fatty acids trigger it in cultured human vascular endothelial cells. Whereas human vascular cell in vitro models are widely established and used for the characterisation of potential vasoprotective substances, such models are not available for canine endothelial cells. In the present study we therefore developed an in vitro model, which allows the testing of the effects of different substances on proliferation and apoptosis in canine aortic endothelial cells. This model was used to test L-carnitine, taurine, pomegranate extract, and Soy Isoflavones in comparison to reference substances (glutathione and pioglitazone) previously shown to modulate human endothelial cell function. L-carnitine and taurine neither exhibited antiproliferative nor antiapoptotic activities in the context of this study. However extracts from pomegranate and soy isoflavones dramatically reduced proliferation and apoptosis in a dose dependent fashion, being in line with a vasoprotective activity in dogs.

Effects of short-term moderate exercise training on sexual function in male patients with chronic stable heart failure

BACKGROUND

Patients with chronic heart failure (CHF) have sexual dysfunction that impairs quality of life. Recent trials have demonstrated that exercise training (ET) improves quality of life (QOL) of CHF patients, but it is not established whether this benefit may be associated with an improvement in sexual dysfunction.

OBJECTIVE

To determine whether ET can improve sexual dysfunction in patients with CHF.

METHODS

We prospectively studied 59 male patients (57+/-9 years) with stable CHF in sinus rhythm and without prostatic disease. Patients were randomized into two groups. A group (T, n = 30) underwent supervised cycle ergometer ET at 60% of peak VO2, three times a week, 60 min each session, for 8 weeks. A group (NT, n = 29) was not exercised. Medications were not changed during the study. On study entry and at 8 weeks all patients underwent a symptom-limited cardiopulmonary exercise testing, brachial artery endothelium-dependent (ED) and endothelium-independent (EI) vasomotor responses, QOL and sexual activity profile assessment (SAP) by questionnaire.

RESULTS

At 8 weeks, no changes were observed in control patients. In trained patients, however, peak VO2 improved by 18% (P < 0.005) and was correlated with QOL (r = 0.80; P < 0.001). Flow-mediated dilation improved in trained patients (from 2.29+/-1.13% to 5.04+/-1.7%, P = 0.0001), while EI dilation (after 0.3 mg sublingual NTG) did not. In group T, all three domains (i.e. Domain 1=relationship with the partner; Domain 2 = quality of penile erection; Domain 3 = personal wellness) were significantly improved from baseline (total score patients: from 3.49+/-3.4 to 6.17+/-3.2, P < 0.001; partners: from 2.47+/-2.7 to 4.87+/-2.5, P < 0.001). Pre-post training change in SAP total score was correlated with changes in coronary risk profile (r = -0.49; P = 0.01), peak VO2 (r = 0.67; P < 0.001) and QOL (r = 0.73; P = 0.01). Multivariate analysis selected the improvement in ED-vasomotor response as the strongest independent predictor of SAP improvement (r = 0.63, P < 0.001).

CONCLUSIONS

In stable CHF, cycle ergometer ET significantly improves brachial artery endothelial dysfunction, suggesting a systemic effect of leg exercise. This benefit was correlated with improvements in sexual activity.

Differences in tail vascular bed reactivity in rats with and without heart failure following myocardial infarction

Myocardial infarction (MI) was induced in rats by coronary ligation to compare changes in vascular reactivity from animals that developed heart failure (InfHF) with those that did not (Inf). Infarct size was similar in both groups. In vitro preparations of tail vascular bed were used to investigate the vascular responses to acetylcholine, sodium nitroprusside, and phenylephrine. Acetylcholine-induced relaxation was impaired in the Inf group (53 +/- 2%, n = 6) when compared with Sham (80 +/- 2%, n = 6, P < 0.05). The maximal response (E(max)) to phenylephrine increased in the Inf group (423 +/- 10 mm Hg, n = 9, P < 0.01) and decreased in InfHF (279 +/- 10 mm Hg, n = 7, P < 0.05) when compared with Sham (319 +/- 11 mm Hg, n = 8). Regardless of endothelial integrity, E(max) to phenylephrine increased in the Inf, nitro-l-arginine methyl ester, and indomethacin groups. An increased release of a prostanoid vasodilator was detected in the Inf group. Differently, the InfHF group presented a reduction of the E(max) to phenylephrine and an increment of nitric oxide release. This study demonstrates that MI without heart failure impairs endothelium-dependent relaxation and increases the reactivity to phenylephrine. This increase seems to involve a muscular component. The endothelium participates with an increased release of a vasodilator prostanoid, possibly to compensate the increased smooth muscle response. When heart failure follows MI, the reactivity to phenylephrine decreases, possibly due to an increased nitric oxide release.

Antioxidant activity of nitro derivative of aspirin against ischemia-reperfusion in hamster cheek pouch microcirculation

Aspirin that has been chemically combined with a nitric oxide (NO) donor (NCX-4016) has been shown to inhibit cyclooxygenase and prostaglandin generation while maintaining the inhibitory effects of aspirin. The possible role of reactive oxygen species (ROS) in the action of NCX-4016 in ischemia-reperfusion (I/R) has not been studied. Furthermore, we were interested in comparing the effects of a conventional NO donor [2,2'-hydroxynitrosohydrazino-bis-etanamine (DETA/NO)] and NCX-4016 at the microvascular level in the hamster cheek pouch visualized by using an intravital fluorescent microscopy technique. Microvascular injury was assessed by measuring diameter change, the perfused capillary length (PCL), and leukocyte adhesion. Animals were treated with NCX-4016 (100 mg/kg or 30 mg.kg(-1).day(-1) for 5 days po) or DETA-NO (0.5 mg/kg). Mean arterial blood pressure increased slightly but significantly after NCX-4016 treatment. During 5- and 15-min reperfusion, lipid peroxides in the systemic blood increased by 72 and 89% vs. baseline, respectively, and were still higher than in basal conditions after 30-min reperfusion in the I/R group. Pretreatment with NCX-4016 maintained ROS at normal levels; increased arteriolar diameter, blood flow, and PCL; and decreased leukocyte adhesion (P < 0.05). DETA-NO decreased ROS during 30-min reperfusion; however, later there was a significant increase during reperfusion. DETA-NO decreased leukocyte adhesion (P < 0.05) but microvascular permeability increased after 30 min of reperfusion. In conclusion, NCX-4016 attenuates oxidative stress and prevents arteriolar constriction during I/R, whereas DETA-NO increases lipid peroxides in the systemic blood and permeability after reperfusion.

The patient with diabetes mellitus and heart failure: at-risk issues

The risk for cardiovascular disease, particularly congestive heart failure, is significantly higher in patients with type 2 diabetes mellitus than in individuals without diabetes. The presence of hyperglycemia has been associated with changes in the myocardium that are characteristic of diabetic cardiomyopathy and heart failure. Furthermore, insulin resistance may be associated with cardiomyopathy, even in the absence of hyperglycemia, and has been linked with cardiovascular remodeling. The association between heart failure and insulin resistance suggests that agents that improve insulin sensitivity, such as the thiazolidinediones (TZDs), are likely to be of cardiovascular benefit in patients with diabetes and heart failure. Although TZDs have beneficial cardiovascular effects in patients with type 2 diabetes, such as reducing blood pressure, improving endothelial function, and exerting potential antiatherosclerotic effects, one must be aware of the potential of these agents to cause edema or weight gain as a result of fluid retention and fat accumulation. These issues are of particular concern in patients with diabetes who have heart failure. However, the glycemic and cardiovascular benefits of TZDs may outweigh the potential problems of weight gain and fluid retention noted in some patients. Thus the risk-benefit ratio of using TZDs in patients who have diabetes and heart failure must be carefully considered in this patient population with comorbid disorders.

Decreased plasma concentration of nitric oxide metabolites in dogs with untreated mitral regurgitation

Endothelium-dependent (nitric oxide [NO]-mediated) vasodilation is impaired in humans with heart failure. This dysfunction is an important therapeutic target. The plasma concentration of the NO metabolites nitrate and nitrite (collectively referred to as NOx) is a measure of whole-body NO production, provided that the dietary intake of the ions is low. Fifty clinically healthy dogs older than I year (median 5.0 years; interquartile interval 2.6-8.2 years) were studied, including 9 controls of various breeds, 23 Cavalier King Charles Spaniels (CKCSs) with no or minimal mitral regurgitation (MR), 9 CKCSs with mild MR (regurgitant jet occupying 15-50% of the left atrial area), and 9 CKCS with moderate to severe MR (jet >50%) due to myxomatous valve disease. None of the dogs received medication. The dogs were given NOx-free water and a diet with a low concentration of NOx for 96 hours before blood sampling. Multiple linear regression analysis revealed that dog group, but not gender, age, serum creatinine concentration, and platelet count, was associated with NOx concentrations. Control dogs had the same NOx concentration (median 20.0 microM; interquartile interval 15.1-25.5 microM) as CKCSs without MR (median 18.7 microM; interquartile interval 15.5-25.9 microM). Compared to CKCSs without MR, the NOx concentration was lower in CKCSs with mild (median 12.9 microM; interquartile interval 11.0-13.5 microM; P = .04) and moderate to severe (median 11.2 microM; interquartile interval 6.9-17.1 microM; P = .02) MR. In conclusion, CKCSs with mild to severe, clinically silent MR have decreased plasma NOx concentrations, suggesting that endothelial dysfunction develops early in the course of developing MR in dogs.

Do results of the ENABLE (Endothelin Antagonist Bosentan for Lowering Cardiac Events in Heart Failure) study spell the end for non-selective endothelin antagonism in heart failure?

The last two decades have seen major advances in the treatment of chronic heart failure, primarily as a result of therapeutic manipulation of activated neurohormonal systems. Despite this progress, many patients still suffer significant morbidity and premature death. Antagonism of the biological effects of endothelin, a potent vasoconstrictor, represents a further potential target. To date, positive results from animal models of heart failure have not been translated into clinical practice, perhaps as a consequence of the high doses of drug used. The ENABLE (Endothelin Antagonist Bosentan for Lowering Cardiac Events in Heart Failure) study evaluated the effects of low dose bosentan, a non-selective endothelin receptor antagonist, in patients with severe heart failure (left ventricular ejection fraction <35%, New York Heart Association class IIIb-IV). A total of 1,613 patients were randomized to receive either bosentan (125 mg twice a day) or placebo. The preliminary results were presented at the 51st Annual Scientific Session of the American College of Cardiology (17-20 March 2002, Atlanta, GA, USA). The primary endpoint of all-cause mortality or hospitalization for heart failure was reached in 321/808 patients on placebo and 312/805 receiving bosentan. Treatment with bosentan appeared to confer an early risk of worsening heart failure necessitating hospitalization, as a consequence of fluid retention. It has been suggested that further studies using even lower doses of bosentan or more aggressive concomitant diuretic therapy may avoid this adverse effect. The results from the ENABLE study have, however, thrown further doubt on the potential benefits of non-specific endothelin receptor blockade in heart failure.

Early dysfunction and long-term improvement in endothelium-dependent vasodilation in the infarct-related artery after thrombolysis

OBJECTIVES

This study assessed the degree of endothelial dysfunction in post-acute myocardial infarction (AMI) and its subsequent status in the infarct-related artery (IRA) in patients treated with thrombolysis.

BACKGROUND

Coronary flow reserve alterations in the IRA after thrombolysis have been described, but the endothelium-dependent vasomotion has not been investigated, to date.

METHODS

Endothelial function in patients after thrombolysis was assessed by infusion of acetylcholine (ACh) at increasing doses in the IRA. Diameter changes in the distal segments were evaluated using quantitative coronary angiography. Patients with coronary atherosclerosis constituted the control group. Clinical variables, electrocardiography and biochemical markers were used to determine the timing of reperfusion and the extent of the infarct. Patients in the AMI group were re-evaluated one year later.

RESULTS

In the initial assessment, 16 patients showed a vasoconstriction response to ACh in the IRA compared to the control group (-20 +/- 21% vs. 4 +/- 4%; p < 0.01). Significant correlations between the degree of vasoconstriction and maximum value of the creatine kinase-MB fraction and number of new Q waves were observed. Of the 12 patients re-evaluated, 4 had complete occlusion of the IRA. In the remaining eight patients with patent artery, an improvement in response to ACh was observed relative to the initial study (+3 +/- 11%, vs. -19 +/- 15%, p < 0.05).

CONCLUSIONS

In patients with AMI treated with thrombolysis, severe endothelial dysfunction in the IRA is observed early. In patients who retain patency of the IRA, the endothelial dysfunction improves during the follow-up and suggests a component of stunned endothelium in the first few days post-AMI.