Chronic stress improves NO- and Ca2+ flux-dependent vascular function: a pharmacological study

Recent Progress of Chronic Stress in the Development of Atherosclerosis

With the development of the times, cardiovascular diseases have become the biggest cause of death in the global aging society, causing a serious social burden. Atherosclerosis is a chronic inflammatory disease, which can occur in large and medium-sized blood vessels in the whole body. It takes atherosclerotic plaque as the typical pathological change and endothelial injury as the core pathophysiological mechanism. It is the pathological basis of coronary heart disease, peripheral artery disease, cerebrovascular disease, and other diseases. Recent studies have shown that chronic stress plays an important role in the occurrence and development of atherosclerosis, endothelial injury, lipid metabolism, and chronic inflammation. This process involves a large number of molecular targets. It is usually the cause of atherosclerotic cardiovascular and cerebrovascular diseases. If chronic stress factors exist for a long time, patients have genetic susceptibility, and the combination of environmental factors triggers the pathogenesis, which may eventually lead to complete blockage of the blood vessels, unstable rupture of plaques, and serious adverse cardiovascular events. This paper reviews the role of chronic stress in the occurrence and development of atherosclerosis, focusing on the pathophysiological mechanism.

Myorelaxant Effect of the Dysphania ambrosioides Essential Oil on Sus scrofa domesticus Coronary Artery and Its Toxicity in the Drosophila melanogaster Model

PURPOSE

Alternative methods for the use of animals in research have gained increasing importance, due to assessments evaluating the real need for their use and the development of legislation that regulates the subject. The principle of the 3R's (replacement, reduction and refinement) has been an important reference, such that in vitro, ex vivo and cord replacement methods have achieved a prominent place in research.

METHODS

Therefore, due to successful results from studies developed with these methods, the present study aimed to evaluate the myorelaxant effect of the Dysphania ambrosioides essential oil (EODa) using a Sus scrofa domesticus coronary artery model, and the toxicity of both the Dysphania ambrosioides essential oil and its major constituent, α-terpinene, against Drosophila melanogaster in toxicity and negative geotaxis assays.

RESULTS

The EODa relaxed the smooth muscle of swine coronary arteries precontracted with K⁺ and 5-HT in assays using Sus scrofa domesticus coronary arteries. The toxicity results presented LC₅₀ values of 1.546 mg/mL and 2.282 mg/mL for the EODa and α-terpinene, respectively, thus showing the EODa and α-terpinene presented toxicity to these dipterans, with the EODa being more toxic.

CONCLUSIONS

Moreover, the results reveal the possibility of using the EODa in vascular disease studies since it promoted the relaxation of the Sus scrofa domesticus coronary smooth muscle.

[Mechanisms of chronic stress influence on the brain hemodynamic in persons with employment-related chronic stress]

OBJECTIVE

To discuss the mechanisms by which chronic psychosocial stress (CPSS) affects the parameters of cerebral blood flow.

MATERIAL AND METHODS

One hundred and sixty locomotive machinists (LM) and machinist assistants (MA), whose profession is rated as one of the most stressful, were enrolled in this study. The control group consisted of 100 healthy volunteers. The activity of the stressor system was assessed by the levels of stress hormones in serum (ACTH, cortisol, adrenaline). The functional state of the endothelium was assessed by secretion of nitric oxide and endothelin-1. Doppler ultrasound was used to measure the linear velocity of blood flow in the cerebral vessels, the size of the intima-media complex of the common carotid artery, and the results of the endothelium-dependent vasodilation. Blood pressure was monitored daily.

RESULTS

The action of CPSS is accompanied by the persistent increase in the serum cortisol levels. This process contributes to the development of vasoconstriction with the initiation of endothelial dysfunction with impaired production of nitric oxide and increased secretion of endothelin-1 and the formation of arterial hypertension. With progression of these processes, there is a decrease in cerebral blood flow. The observed increase in the size of the intima-media complex of the common carotid artery correlates with the severity of arterial hypertension and endothelial dysfunction.

CONCLUSIONS

CPSS leads to a decrease in cerebral blood flow and subsequent development of endothelial dysfunction and arterial hypertension, which are related to high levels of stress hormones circulating in the blood. These processes lead to functional failure of the vascular endothelium.

Pregnancy-specific stress, fetoplacental haemodynamics, and neonatal outcomes in women with small for gestational age pregnancies: a secondary analysis of the multicentre Prospective Observational Trial to Optimise Paediatric Health in Intrauterine Growth Restriction

OBJECTIVES

To examine associations between maternal pregnancy-specific stress and umbilical (UA PI) and middle cerebral artery pulsatility indices (MCA PI), cerebroplacental ratio, absent end diastolic flow (AEDF), birthweight, prematurity, neonatal intensive care unit admission and adverse obstetric outcomes in women with small for gestational age pregnancies. It was hypothesised that maternal pregnancy-specific stress would be associated with fetoplacental haemodynamics and neonatal outcomes.

DESIGN

This is a secondary analysis of data collected for a large-scale prospective observational study.

SETTING

This study was conducted in the seven major obstetric hospitals in Ireland and Northern Ireland.

PARTICIPANTS

Participants included 331 women who participated in the Prospective Observational Trial to Optimise Paediatric Health in Intrauterine Growth Restriction. Women with singleton pregnancies between 24 and 36 weeks gestation, estimated fetal weight <10th percentile and no major structural or chromosomal abnormalities were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Serial Doppler ultrasound examinations of the umbilical and middle cerebral arteries between 20 and 42 weeks gestation, Pregnancy Distress Questionnaire (PDQ) scores between 23 and 40 weeks gestation and neonatal outcomes.

RESULTS

Concerns about physical symptoms and body image at 35-40 weeks were associated with lower odds of abnormal UAPI (OR 0.826, 95% CI 0.696 to 0.979, p=0.028). PDQ score (OR 1.073, 95% CI 1.012 to 1.137, p=0.017), concerns about birth and the baby (OR 1.143, 95% CI 1.037 to 1.260, p=0.007) and concerns about physical symptoms and body image (OR 1.283, 95% CI 1.070 to 1.538, p=0.007) at 29-34 weeks were associated with higher odds of abnormal MCA PI. Concerns about birth and the baby at 29-34 weeks (OR 1.202, 95% CI 1.018 to 1.421, p=0.030) were associated with higher odds of AEDF. Concerns about physical symptoms and body image at 35-40 weeks were associated with decreased odds of neonatal intensive care unit admission (OR 0.635, 95% CI 0.435 to 0.927, p=0.019).

CONCLUSIONS

These findings suggest that fetoplacental haemodynamics may be a mechanistic link between maternal prenatal stress and fetal and neonatal well-being, but additional research is required.

Blood pressure regulation in stress: focus on nitric oxide-dependent mechanisms

Stress is considered a risk factor associated with the development of various civilization diseases including cardiovascular diseases, malignant tumors and mental disorders. Research investigating mechanisms involved in stress-induced hypertension have attracted much attention of physicians and researchers, however, there are still ambiguous results concerning a causal relationship between stress and long-term elevation of blood pressure (BP). Several studies have observed that mechanisms involved in the development of stress-induced hypertension include increased activity of sympathetic nervous system (SNS), glucocorticoid (GC) overload and altered endothelial function including decreased nitric oxide (NO) bioavailability. Nitric oxide is well known neurotransmitter, neuromodulator and vasodilator involved in regulation of neuroendocrine mechanisms and cardiovascular responses to stressors. Thus NO plays a crucial role in the regulation of the stress systems and thereby in the BP regulation in stress. Elevated NO synthesis, especially in the initial phase of stress, may be considered a stress-limiting mechanism, facilitating the recovery from stress to the resting levels via attenuation of both GC release and SNS activity as well as by increased NO-dependent vasorelaxation. On the other hand, reduced levels of NO were observed in the later phases of stress and in subjects with genetic predisposition to hypertension, irrespectively, in which reduced NO bioavailability may account for disruption of NO-mediated BP regulatory mechanisms and accentuated SNS and GC effects. This review summarizes current knowledge on the role of stress in development of hypertension with a special focus on the interactions among NO and other biological systems affecting blood pressure and vascular function.

Emotional Stress and Cardiovascular Complications in Animal Models: A Review of the Influence of Stress Type

Emotional stress has been recognized as a modifiable risk factor for cardiovascular diseases. The impact of stress on physiological and psychological processes is determined by characteristics of the stress stimulus. For example, distinct responses are induced by acute vs. chronic aversive stimuli. Additionally, the magnitude of stress responses has been reported to be inversely related to the degree of predictability of the aversive stimulus. Therefore, the purpose of the present review was to discuss experimental research in animal models describing the influence of stressor stimulus characteristics, such as chronicity and predictability, in cardiovascular dysfunctions induced by emotional stress. Regarding chronicity, the importance of cardiovascular and autonomic adjustments during acute stress sessions and cardiovascular consequences of frequent stress response activation during repeated exposure to aversive threats (i.e., chronic stress) is discussed. Evidence of the cardiovascular and autonomic changes induced by chronic stressors involving daily exposure to the same stressor (predictable) vs. different stressors (unpredictable) is reviewed and discussed in terms of the impact of predictability in cardiovascular dysfunctions induced by stress.