Sex differences in brain activation patterns with mental stress in patients with coronary artery disease

Stress and cardiovascular disease: an update

Psychological stress is generally accepted to be associated with an increased risk of cardiovascular disease (CVD), but results have varied in terms of how stress is measured and the strength of the association. Additionally, the mechanisms and potential causal links have remained speculative despite decades of research. The physiological responses to stress are well characterized, but their contribution to the development and progression of CVD has received little attention in empirical studies. Evidence suggests that physiological responses to stress have a fundamental role in the risk of CVD and that haemodynamic, vascular and immune perturbations triggered by stress are especially implicated. Stress response physiology is regulated by the corticolimbic regions of the brain, which have outputs to the autonomic nervous system. Variation in these regulatory pathways might explain interindividual differences in vulnerability to stress. Dynamic perturbations in autonomic, immune and vascular functions are probably also implicated as CVD risk mechanisms of chronic, recurring and cumulative stressful exposures, but more data are needed from prospective studies and from assessments in real-life situations. Psychological assessment remains insufficiently recognized in clinical care and prevention. Although stress-reduction interventions might mitigate perceived stress levels and potentially reduce cardiovascular risk, more data from randomized trials are needed.

Machine learning reveals sex differences in clinical features of acute exacerbation of chronic obstructive pulmonary disease: A multicenter cross-sectional study

Introduction

Intrinsically, chronic obstructive pulmonary disease (COPD) is a highly heterogonous disease. Several sex differences in COPD, such as risk factors and prevalence, were identified. However, sex differences in clinical features of acute exacerbation chronic obstructive pulmonary disease (AECOPD) were not well explored. Machine learning showed a promising role in medical practice, including diagnosis prediction and classification. Then, sex differences in clinical manifestations of AECOPD were explored by machine learning approaches in this study.

Methods

In this cross-sectional study, 278 male patients and 81 female patients hospitalized with AECOPD were included. Baseline characteristics, clinical symptoms, and laboratory parameters were analyzed. The K-prototype algorithm was used to explore the degree of sex differences. Binary logistic regression, random forest, and XGBoost models were performed to identify sex-associated clinical manifestations in AECOPD. Nomogram and its associated curves were established to visualize and validate binary logistic regression.

Results

The predictive accuracy of sex was 83.930% using the k-prototype algorithm. Binary logistic regression revealed that eight variables were independently associated with sex in AECOPD, which was visualized by using a nomogram. The AUC of the ROC curve was 0.945. The DCA curve showed that the nomogram had more clinical benefits, with thresholds from 0.02 to 0.99. The top 15 sex-associated important variables were identified by random forest and XGBoost, respectively. Subsequently, seven clinical features, including smoking, biomass fuel exposure, GOLD stages, PaO2, serum potassium, serum calcium, and blood urea nitrogen (BUN), were concurrently identified by three models. However, CAD was not identified by machine learning models.

Conclusions

Overall, our results support that the clinical features differ markedly by sex in AECOPD. Male patients presented worse lung function and oxygenation, less biomass fuel exposure, more smoking, renal dysfunction, and hyperkalemia than female patients with AECOPD. Furthermore, our results also suggest that machine learning is a promising and powerful tool in clinical decision-making.

The Impact of Mental Stress on Cardiovascular Health—Part II

Endothelial dysfunction is one of the earliest manifestations of atherosclerosis, contributing to its development and progression. Mental stress induces endothelial dysfunction through increased activity of the sympathetic nervous system, release of corticotropin-releasing hormone from the hypothalamus, inhibition of nitric oxide (NO) synthesis by cortisol, and increased levels of pro-inflammatory cytokines. Mental-stress-induced increased output of the sympathetic nervous system and concomitant withdrawal of the parasympathetic inflammatory reflex results in systemic inflammation and activation of a neural–hematopoietic–arterial axis. This includes the brainstem and subcortical regions network, bone marrow activation, release of leukocytes into the circulation and their migration to the arterial wall and atherosclerotic plaques. Low-grade, sterile inflammation is involved in all steps of atherogenesis, from coronary plaque formation to destabilisation and rupture. Increased sympathetic tone may cause arterial smooth-muscle-cell proliferation, resulting in vascular hypertrophy, thus contributing to the development of hypertension. Emotional events also cause instability of cardiac repolarisation due to brain lateralised imbalance of cardiac autonomic nervous stimulation, which may lead to asymmetric repolarisation and arrhythmia. Acute emotional stress can also provoke severe catecholamine release, leading to direct myocyte injury due to calcium overload, known as myocytolysis, coronary microvascular vasoconstriction, and an increase in left ventricular afterload. These changes can trigger a heart failure syndrome mimicking acute myocardial infarction, characterised by transient left ventricular dysfunction and apical ballooning, known as stress (Takotsubo) cardiomyopathy. Women are more prone than men to develop mental-stress-induced myocardial ischemia (MSIMI), probably reflecting gender differences in brain activation patterns during mental stress. Although guidelines on CV prevention recognise psychosocial factors as risk modifiers to improve risk prediction and decision making, the evidence that their assessment and treatment will prevent CAD needs further evaluation.

Mental Stress-Induced Myocardial Ischemia

PURPOSE OF REVIEW

To summarize recent evidence on mental stress-induced myocardial ischemia (MSIMI), its mechanisms, and clinical significance.

RECENT FINDINGS

MSIMI can occur in patients with normal cardiac stress testing, is only weakly related to severity of coronary artery disease (CAD), and it is often silent. Among patients with CAD, MSIMI is associated with a twofold increased risk of major adverse cardiovascular events compared to those who do not have MSIMI. Certain groups such as young women with myocardial infarction and those with psychological comorbidities are more susceptible to MSIMI. Abnormal microvascular vasoreactivity and inflammation are implicated mechanisms in MSIMI. Increased brain activity in regions that modulate autonomic reactivity to emotional stress and fear is associated with MSIMI. MSIMI has important prognostic implications in patients with CAD. Stress can no longer be ignored as a risk factor in cardiology care. Clinical trials testing effective strategies to target MSIMI are needed.

Brain-heart connections in stress and cardiovascular disease: Implications for the cardiac patient

The influence of psychological stress on the physiology of the cardiovascular system, and on the etiology and outcomes of cardiovascular disease (CVD) has been the object of intense investigation. As a whole, current knowledge points to a "brain-heart axis" that is especially important in individuals with pre-existing CVD. The use of acute psychological stress provocation in the laboratory has been useful to clarify the effects of psychological stress on cardiovascular physiology, immune function, vascular reactivity, myocardial ischemia, neurobiology and cardiovascular outcomes. An emerging paradigm is that dynamic perturbations of physiological and molecular pathways during stress or negative emotions are important in influencing cardiovascular outcomes, and that some patient subgroups, such as women, patients with an early-onset myocardial infarction, and patients with adverse psychosocial exposures, may be at especially high risk for these effects. This review summarizes recent knowledge on mind-body connections in CVD among cardiac patients and highlights important pathways of risk which could become the object of future intervention efforts. As a whole, this research suggests that an integrated study of mind and body is necessary to fully understand the determinants and consequences of CVD.

Neural responses during acute mental stress are associated with angina pectoris

Angina pectoris is associated with increased risk of adverse cardiovascular events in coronary artery disease (CAD) patients, an effect not entirely attributable to the severity of CAD.

OBJECTIVE

Examine brain correlates of mental stress in patients with CAD with and without a history of angina.

METHODS

Participants (n = 170) with stable CAD completed the Seattle Angina Questionnaire along with other psychometric assessments. In this cross-sectional study, participants underwent laboratory-based mental stress testing using mental arithmetic and public speaking tasks along with control conditions in conjunction with positron emission tomography brain imaging using radiolabeled water. Brain activity during mental stress was compared between participants who did or did not report chest pain/angina in the previous month. A factor analysis was coupled with dominance analysis to identify brain regions associated with angina.

RESULTS

Participants reporting angina in the past month experienced greater (p < .005) activations within the left: frontal lobe (z = 4.01), temporal gyrus (z = 3.32), parahippocampal gyrus (z = 3.16), precentral gyrus (z = 3.14), right fusiform gyrus (z = 3.07), and bilateral cerebellum (z = 3.50) and deactivations within the right frontal gyrus (z = 3.67), left precuneus (z = 3.19), and left superior temporal gyrus (z = 3.11) during mental stress. A factor containing the left motor areas, inferior frontal lobe, and operculum (average McFadden's number addition = 0.057) in addition to depression severity (0.10) and adulthood trauma exposure (0.064) correlated with angina history.

CONCLUSIONS

Self-reported angina in patients with stable CAD is associated with increased neural responses to stress in a network including the inferior frontal lobe, motor areas, and operculum, potentially indicating an upregulated pain perception response.

What about heart and mind in the COVID-19 era?

From the time of Hippocratic medicine, heart-brain interactions have been recognized and contributed to both mental and physical health. Heart-brain interactions are complex and multifaceted and appear to be bidirectional. Exposure to chronic and daily stressors such as quarantine, or severe psychological trauma like a significant person in danger of life can affect the cardiovascular system and the emotional experience of the individual, leading to an increased risk of developing a cardiovascular disease or mental illness. Subjects with comorbidities between mental disorders and heart diseases are obviously more susceptible to be influenced by emotional burden due to the spread of COVID-19, with emotional responses characterized by fear, panic, anger, frustration. Psychological services and crisis interventions are needed at an early stage to reduce anxiety, depression and post-traumatic stress disorder in such a stressful period, with a special attention to special groups of patients, such as women, children, or the elderly.

Dapagliflozin Activates Neurons in the Central Nervous System and Regulates Cardiovascular Activity by Inhibiting SGLT-2 in Mice

PURPOSE

This study investigates the possible effect and central mechanism of novel antidiabetic medication sodium glucose transporter-2 (SGLT-2i) on the cardiovascular activity.

MATERIAL AND METHODS

Thirty-four normal male C57BL/6 mice were randomly assigned to 2 groups to receive single Dapagliflozin (1.52mg/kg) dose via intragastric gavage or a comparable dose of saline. Glycemic level (BG), blood pressure (BP) and heart rate (HR) were measured 2 hours after administration of the respective treatments. Immunohistochemical tests were performed to determine the effect of SGLT-2i on neural localization of SGLT-2 and c-Fos, a neural activator. The distributional relationships of SGLT-2 and c-Fos were examined by immunofluorescence.

RESULTS

Administration of SGLT-2i significantly decreased BP but did not affect the HR. There was no difference in BG between the two groups. Results showed that SGLT-2 was localized to specific regions involved in autonomic control. Expression of c-Fos was significantly higher in major critical nuclei in the aforementioned regions in groups treated with Dapagliflozin.

CONCLUSION

This study demonstrates that SGLT-2 is expressed in CNS tissues involved in autonomic control and possibly influence cardiovascular function. Dapagliflozin influences central autonomic activity via unidentified pathways by inhibiting central or peripheral SGLT-2. These results provide a new concept that sympathetic inhibition by SGLT-2i can be mediated by central autonomic system, a mechanism that explains how SGLT-2i improves the cardiovascular function.