Neurally mediated syncope: Is it really an endothelial dysfunction?

Flow-Mediated Dilation, a Marker of Endothelial Cell Dysfunction, in Patients with Pulmonary Hypertension

Background

Flow-mediated dilation (FMD) is considered a marker of endothelial cell dysfunction (ECD) and has been mostly evaluated in coronary artery disease. The role of ECD in the pathogenesis of pulmonary hypertension (PH) is not well-known. This study sought to evaluate the relationship between FMD and PH.

Materials and Methods

In this cross-sectional study, the FMD of the brachial artery was measured in 40 confirmed PH patients. Meanwhile, echocardiographic findings, the 6-minute walk test (6MWT), and serum pro-brain natriuretic peptide (pro-BNP) level were evaluated. Overall, 20 patients accomplished all evaluations, and their data were analyzed using SPSS software (version 23).

Results

There was an inverse relationship between pro-BNP and 6MWT (r<0, P<0.05). A significant direct relationship was observed between left ventricular ejection fraction and FMD (P=0.031). Right ventricular (RV) dilation was significantly correlated with pro-BNP (P=0.046). There was a significant direct correlation between RV function and FMD and a significant inverse relationship between pro-BNP and FMD (P=0.05). The independent t-test showed no relationship between FMD and syncope (P=0.75).

Conclusion

Endothelial cell function, which can be evaluated by FMD, was involved in patients with PH. The FMD and 6MWT were helpful as objective prognostic markers in PH. Furthermore, pro-BNP was a noninvasive indicator in the diagnosis of RV systolic dysfunction.

Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic Aldehyde Reduces Atherosclerosis and Attenuates Low-Shear Stress-Induced Vascular Endothelial Cell Dysfunction

Background: The Fufang Danshen formula is a clinically important anti-atherosclerotic preparation in traditional Chinese medicine. However, its anti-atherosclerotic effect is not well recognized, and the mechanisms of its combined active ingredients, namely Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic aldehyde (RRP), remain unclear. The purpose of this study was to investigate the anti-atherosclerotic effects and potential mechanism of RRP in ApoE-/- mice and in low-shear stress-injured vascular endothelial cells. Methods: ApoE-/- mice were randomly divided into three groups: model group, rosuvastatin group, and RRP group, with C57BL/6J mice as the control group. Oil-red O, hematoxylin and eosin, Masson, and Movat staining were utilized for the observation of aortic plaque. Changes in the blood lipid indexes were observed with an automatic biochemistry analyzer. ET-1, eNOS, TXA2, and PGI2 levels were analyzed by enzyme-linked immunosorbent assay. In vitro, a fluid shear stress system was used to induce cell injury. Piezo1 expression in HUVECs was silenced using siRNA. Changes in morphology, proliferation, migration, and tube formation activity of cells were observed after RRP treatment. Quantitative Real-Time PCR and western blot analysis were employed to monitor mRNA and protein expression. Results: RRP treatment reduced the atherosclerotic area and lipid levels and improved endothelial function in ApoE-/- mice. RRP significantly repaired cell morphology, reduced excessive cell proliferation, and ameliorated migration and tube formation activity. In addition, RRP affected the FAK-PI3K/Akt signaling pathway. Importantly, Piezo1 silencing abolished the protective effects of RRP. Conclusion: RRP has anti-atherosclerotic effects and antagonizes endothelial cell damage via modulating the FAK-PI3K/Akt signaling pathway. Piezo1 is a possible target of RRP in the treatment of atherosclerosis. Thus, RRP has promising therapeutic potential and broad application prospect for atherosclerosis.

Acute hypotension attenuates brachial flow-mediated dilation in young healthy men

PURPOSE

This study aimed to test our hypothesis that acute hypotension attenuates brachial flow-mediated dilation (FMD) as an index of endothelial function in healthy humans.

METHODS

Twelve healthy men (21.8 ± 1.6 years, body mass index; 22.2 ± 1.6 kg/m²) participated in this study. Brachial FMD was measured in three trials: standardized FMD protocol (control trial), abrupt decrease in blood pressure (BP) via thigh cuff inflation-deflation (hypotension trial) and decrease in shear rate (SR) via a shortened forearm occlusion time (SR reduction trial). Brachial diameter and blood velocity were measured using Duplex ultrasound.

RESULTS

Mean arterial pressure during reactive hyperaemia showed a marked decrease in the hypotension trial (- 23.7 ± 6.0 mmHg), but not in the control and SR reduction trials. SR area under the curve was attenuated in the SR reduction trial (P < 0.001), but not in the control and hypotension trials (P = 0.316). Consequently, FMD was attenuated in the hypotension and SR reduction trials compared with that in the control trial (P = 0.003 and P = 0.043, respectively), and was attenuated to a greater extent in the hypotension trial compared with the SR reduction trial (P = 0.006; control, 6.9 ± 3.5%; hypotension, 3.5 ± 1.7%; SR reduction, 5.0 ± 2.2%). After adjusting FMD using SR, FMD remained attenuated in the hypotension trial (P = 0.014), but not in the SR reduction trial.

CONCLUSION

Our findings indicate that arterial pressure as well as sympathetic nervous system activation could be an important determinant of FMD. Blunted FMD of peripheral arteries may be a rational response to restore BP and/or prevent further reduction of BP following acute hypotension in healthy humans.

Endothelial dysfunction state in migraine headache and neutrally mediated syncope in children and young adults

Background:

Recent evidences have supported migraine headache and neurally mediated syncope as the especial types of endotheliopathies. To determine endothelial function in patients with migraine headache or those with neurally mediated syncope, the present study was conducted.

Materials and Methods:

This cross-sectional study was performed on 93 consecutive patients aged 5-20 years in four groups; neurally mediated syncope, migraine, both neurally mediated syncope and migraine, and control groups. All subjects were tested for basic biophysical and biochemical features including age, gender, body mass index, systolic, and diastolic blood pressures, intima-media thickness (IMT) and flow-mediated dilation (FMD), blood hemoglobin, fasting blood glucose, lipid profile, intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and E-selectin.

Results:

The mean levels of VCAM and ICAM were significantly higher in all groups when compared to control group (P < 0.05). FMD was significantly higher in syncope, migraine, and syncope and migraine groups than in the control group (P < 0.05). Furthermore, mean IMT was significantly lower in migraine and also in syncope and migraine groups than in syncope group and control group (P < 0.05). Examining the association between IMT and other baseline parameters showed positive association of IMT with systolic and diastolic blood pressures.

Conclusion:

Endothelial dysfunction is seen in both migraine headache and neurally mediated syncope. Changes in endothelial functional indices are also dependent on the blood pressure.