Acute effects of moderate altitude on biomarkers of cardiovascular inflammation and endothelial function and their differential modulation by dual endothelin receptor blockade

Changes in the pulmonary circulation due to gravitational loads in high altitude conditions

BACKGROUND

The impact of gravity on the existence of all living things has long been of interest to scientists. The force of the Earth's gravity combined with hypoxia significantly affects blood circulation and blood accumulation in various parts of the human and animal body. To date, the relationship between body position and blood circulation in pulmonary circulation under hypobaric hypoxia has not been sufficiently studied.

OBJECTIVES

Therefore, the research aims to determine the possibility of changing the body position in space on the reactions in the pulmonary circulation in the plains and highlands.

METHODS

For this purpose, research was conducted on male Wistar rats, 44 of whom spent 150 days at an altitude of 3200 m above sea level, and 25 representatives of the control group - at an altitude of 164 m.

RESULTS

The study revealed that gravitational redistribution of blood in mountainous conditions is less pronounced compared to the control group. This is explained by the remodeling of the vascular wall and an increase in its stiffness. It was found that a change in pulmonary artery pressure at the time of a change in body position was recorded both on the plains and in the highlands. On the plains, when the body position of rats was changed to passive orthostatic, a decrease in systolic and diastolic pulmonary artery pressure was noted, and when the body position was changed to passive anti-orthostatic, an increase in pulmonary artery pressure was observed. The increase in pulmonary artery pressure was a compensatory mechanism due to the increased stiffness of the pulmonary vasculature.

CONCLUSIONS

The practical significance of this research is to expand the understanding of the pathogenesis of pulmonary hypertension in high-altitude hypoxia.

Independent impact of periodontitis and cardiovascular disease on elevated soluble urokinase-type plasminogen activator receptor (suPAR) levels

BACKGROUND

Previous studies have demonstrated that a soluble urokinase-type plasminogen activator receptor (suPAR) plays an essential function in leukocytes and endothelial homeostasis and, therefore, in the development of coronary heart disease (CHD) and periodontitis. The aim of this study was to analyze the impact of gingival health, periodontitis, and CHD on suPAR levels in plasma and saliva and to evaluate suPAR as a biomarker of periodontitis and CHD.

METHODS

Healthy controls (n = 33), patients with periodontitis (n = 31), CHD (n = 29), and a combination of periodontitis + CHD (n = 29) were enrolled in the present study. All patients were clinically and periodontally evaluated and regularly assessed for socioeconomic status, serum lipids, high-sensitivity C-reactive protein (hs-CRP), and for plasma and salivary suPAR levels.

RESULTS

Patients with periodontitis (P <.001) and with periodontitis + CHD (P <.001) presented higher median plasma and salivary suPAR levels compared with CHD and healthy controls. Moreover, univariate regression analysis demonstrated that hs-CRP (P <.001) and periodontitis (P <.001) had a significant negative direct effect on both plasma and salivary suPAR levels. The multivariate regression analysis showed that periodontitis was the only significant predictor of plasma suPAR (P = .035) while hs-CRP was the only significant predictor of salivary suPAR (P <.001).

CONCLUSIONS

The results of the present study demonstrated that patients with periodontitis and periodontitis + CHD presented higher suPAR levels in both plasma and saliva in comparison with healthy controls and CHD. Moreover, periodontitis and hs-CRP were the only significant predictors of the augmented suPAR levels in plasma and saliva, respectively.

Protective Mechanisms of Quercetin Against Myocardial Ischemia Reperfusion Injury

Quercetin has attracted more attention in recent years due to its protective role against ischemia/reperfusion injury. Quercetin can alleviate oxidative stress injury through the inhibition of NADPH oxidase and xanthine oxidase, blockage of the Fenton reaction, and scavenging of reactive oxygen species. Quercetin can also exert anti-inflammatory and anti-apoptotic effects by reducing the response to inflammatory factors and inhibiting cell apoptosis. Moreover, it can induce vasodilation effects through the inhibition of endothelin-1 receptors, the enhancement of NO stimulation and the activation of the large-conductance calcium-activated potassium channels. Finally, Quercetin can also antagonize the calcium overload. These multifaceted activities of Quercetin make it a potential therapeutic alternative for the treatment of ischemia/reperfusion injury.

Evolution of blood rheology and its relationship to pulmonary hemodynamic during the first days of exposure to moderate altitude

Blood rheology and hemodynamic parameters have never been explored together during acclimatization to altitude. This study aimed to investigate changes in blood rheology parameters and pulmonary hemodynamics during the first days of real moderate altitude exposure.Seventeen athletes were tested at sea-level, 20 hours after their arrival at 2,400 meters of altitude (H1) and five days later (H2). Blood was sampled to analyze red blood cell (RBC) aggregation, blood viscosity and hematocrit. Pulmonary arterial pressure (PAP), pulmonary capillary pressure (Pcap) and pulmonary vascular resistance (PVR) were assessed by echocardiography.We observed a rise in hematocrit, blood viscosity, RBC aggregation, PAP, Pcap and PVR between sea-level and H1. In H2, RBC aggregation, hematocrit, PAP, Pcap and PVR remained different compared to sea-level and no difference was observed between H1 and H2. Blood viscosity decreased in H2 and returned to sea-level values.Our results suggest that hemoconcentration occurring within the first hours of altitude exposure increased blood viscosity, which contributed to the changes in pulmonary hemodynamic. When blood viscosity decreased in H2, no change occurred in pulmonary hemodynamic parameters suggesting that hypoxic pulmonary vasoconstriction was still present. The elevated RBC aggregation observed after in H2 could participate in the increase of Pcap.

Endothelial microvesicles in hypoxic hypoxia diseases

Hypoxic hypoxia, including abnormally low partial pressure of inhaled oxygen, external respiratory dysfunction-induced respiratory hypoxia and venous blood flow into the arterial blood, is characterized by decreased arterial oxygen partial pressure, resulting in tissue oxygen deficiency. The specific characteristics include reduced arterial oxygen partial pressure and oxygen content. Hypoxic hypoxia diseases (HHDs) have attracted increased attention due to their high morbidity and mortality and mounting evidence showing that hypoxia-induced oxidative stress, coagulation, inflammation and angiogenesis play extremely important roles in the physiological and pathological processes of HHDs-related vascular endothelial injury. Interestingly, endothelial microvesicles (EMVs), which can be induced by hypoxia, hypoxia-induced oxidative stress, coagulation and inflammation in HHDs, have emerged as key mediators of intercellular communication and cellular functions. EMVs shed from activated or apoptotic endothelial cells (ECs) reflect the degree of ECs damage, and elevated EMVs levels are present in several HHDs, including obstructive sleep apnoea syndrome and chronic obstructive pulmonary disease. Furthermore, EMVs have procoagulant, proinflammatory and angiogenic functions that affect the pathological processes of HHDs. This review summarizes the emerging roles of EMVs in the diagnosis, staging, treatment and clinical prognosis of HHDs.

In the View of Endothelial Microparticles: Novel Perspectives for Diagnostic and Pharmacological Management of Cardiovascular Risk during Diabetes Distress

Acute or chronic exposure to diabetes-related stressors triggers a specific psychological and behavior stress syndrome called diabetes distress, which underlies depressive symptoms in most diabetic patients. Distressed and/or depressive diabetic adults exhibit higher rates of cardiovascular mortality and morbidity, which have been correlated to macrovascular complications evoked by diabetic behavior stress. Recent experimental findings clearly point out that oxidative stress accounts for the vascular dysfunction initiated by the exposure to life stressors in diabetic conditions. Moreover, oxidative stress has been described as the main autocrine and paracrine mechanism of cardiovascular damage induced by endothelial microparticles (anuclear ectosomal microvesicles released from injured endothelial cells) in diabetic subjects. Such robust relationship between oxidative stress and cardiovascular diseases strongly suggests a critical role for endothelial microparticles as the primer messengers of the redox-dependent vascular dysfunction underlying diabetes distress. Here, we provide novel perspectives opened in the view of endothelial microparticles as promising diagnostic and pharmacotherapeutic biomarkers of cardiovascular risk in distressed diabetic patients.