Gut microbiota connects the brain and the heart: potential mechanisms and clinical implications

Nowadays, high morbidity and mortality of cardiovascular diseases (CVDs) and high comorbidity rate of neuropsychiatric disorders contribute to global burden of health and economics. Consequently, a discipline concerning abnormal connections between the brain and the heart and the resulting disease states, known as psychocardiology, has garnered interest among researchers. However, identifying a common pathway that physicians can modulate remains a challenge. Gut microbiota, a constituent part of the human intestinal ecosystem, is likely involved in mutual mechanism CVDs and neuropsychiatric disorder share, which could be a potential target of interventions in psychocardiology. This review aimed to discuss complex interactions from the perspectives of microbial and intestinal dysfunction, behavioral factors, and pathophysiological changes and to present possible approaches to regulating gut microbiota, both of which are future directions in psychocardiology.

Impact of antidepressant use on the autonomic nervous system: A meta-analysis and systematic review

Changes in cardiac autonomic nervous system (ANS) regulation observed in psychiatric disorders may be mitigated by antidepressants. We meta-analyzed and systematically reviewed studies examining antidepressants' effects on ANS outcomes, including heart rate variability (HRV). We conducted a PRISMA/MOOSE-compliant search of PubMed and Scopus until March 28th, 2022. We included randomized placebo-controlled trials (RCTs) and pre-post studies, regardless of diagnosis. We pooled results in random-effects meta-analyses, pooling homogeneous study designs and outcomes. We conducted sensitivity analyses and assessed quality of included studies. Thirty studies could be meta-analyzed. Selective serotonin reuptake inhibitors (SSRIs) were significantly associated with a reduction in the square root of the mean-squared difference between successive R-R intervals (RMSSD) (SMD= -0.48) and skin conductance response (SMD= -0.55) in RCTs and with a significant increase in RMSSD in pre-post studies (SMD=0.27). In pre-post studies, tricyclic antidepressants (TCAs) were associated with a significant decrease in several HRV outcomes while agomelatine was associated with a significant increase in high frequency power (SMD= 0.14). In conclusion, SSRIs reduce skin conductance response but have no or inconclusive effects on other ANS outcomes, depending on study design. TCAs reduce markers of parasympathetic function while agomelatine might have the opposite effect. Studies are needed to investigate the impact of SSRIs on the recovery of cardiac ANS regulation after acute myocardial infarction, and the effects of newer antidepressants.

Sex-specific psychological risk profiles of CVD in the HUNT study: the role of neuroticism and extraversion

OBJECTIVE

The aim was to investigate psychological risk profiles of cardiovascular disease (CVD). Depression and anxiety have been linked to CVD, but research has not incorporated personality and sex-specific analyses are warranted. In this study, we examine the role of sex, neuroticism, extraversion, anxiety and depression on the risk of CVD.

METHOD

Using data from the HUNT-study and the mortality register, 32,383 (57.10% men) participants were followed for an average of 10.48 years. During this time, 142 died of myocardial infarction (MI) and 111 of stroke.

RESULTS

Cox regression showed that depression (HR = 1.07, 95% CI = [1.00, 1.14]) and neuroticism (1.23 [1.08, 1.40]) were significantly related to an increased risk of MI. One standard unit increase in depression and neuroticism was associated with 1.22 [CI 1.01, 1.47] increase and 1.43 [CI 1.14, 0.78] increase in the risk of MI respectively. For stroke, there was no significant effect of anxiety, depression or personality. However, we found a significant interaction effect between sex and extraversion where higher extraversion was associated with greater risk of stroke for women only.

CONCLUSIONS

Both neuroticism and depression were related to MI. We observed an interaction between extraversion and sex with stroke, but the effect size was small. The role of extroversion as a risk factor for CVD remains inconclusive.

Mind and body interventions in cardiology : The importance of the brain-heart connection

Mind and body interventions aim to harness the "relaxation response", reduce stress, and improve quality of life, which is important in the search for more holistic treatment approaches in cardiovascular medicine. This article describes the pertinent pathophysiological correlates building the mechanistic backbone for these interventions. They can be found in the complex connections of brain and heart (central and autonomic nervous system, hypothalamic-pituitary-adrenal axis), which play an important role in the development of various cardiovascular disease conditions and hold potential as therapeutic targets. The evidence regarding the effect of mind and body interventions in cardiology with a focus on arrhythmia and psychocardiology is reviewed systematically. To date, mostly small pilot studies prone to substantial bias and without adequate power have dominated the field and longer-term outcome data are lacking. Ultimately, integration of mind and body interventions could empower patients by strengthening their individual responsibility and mental power in addition to the benefits of stress reduction and improvement of quality of life. Whether this will translate into relevant longer-term clinical outcomes remains uncertain. Therefore, this field offers multifaceted opportunities for further research and practical applications.

Mechanisms supporting potential use of bone marrow-derived mesenchymal stem cells in psychocardiology

Despite great efforts made in recent years, globally cardiovascular disease (CVD) remains the most common and devastating disease. Pharmacological, interventional and surgical treatments have proved to be only partly satisfactory for the majority of patients. A major underlying cause of poor prognosis is a high comorbidity rate between CVD and mental illness, which calls for the approaches of psychocardiology. As psychiatric disorders and CVD can influence each other bidirectionally, it is necessary to develop novel therapies targeting both systems simultaneously. Therefore, innovative stem cell (SC) therapy has become the most promising treatment strategy in psychocardiology. Bone marrow-derived mesenchymal stem/stromal cells (BM-MSCs), among all different types of SCs, have drawn the most attention due to unique advantages in terms of ethical considerations, low immunogenicity and simplicity of preparation. In this review, we survey recent publications and clinical trials to summarize the knowledge and progress gained so far. Moreover, we discuss the feasibility of the clinical application of BM-MSCs in the area of psychocardiology.