Takotsubo cardiomyopathy: do the genetics matter?

Takotsubo syndrome: getting closer to its causes

Takotsubo syndrome (TTS) accounts for between 1 and 4% of cases presenting clinically as an acute coronary syndrome. It typically presents as a transient cardiac phenotype of left ventricular dysfunction with spontaneous recovery. More dramatic presentations may include cardiogenic shock or cardiac arrest. Despite progress in the understanding of the condition since its first description in 1990, considerable questions remain into understanding underlying pathomechanisms. In this review article, we describe the current published data on potential underlying mechanisms associated with the onset of TTS including sympathetic nervous system over-stimulation, structural and functional alterations in the central nervous system, catecholamine secretion, alterations in the balance and distribution of adrenergic receptors, the additive impact of hormones including oestrogen, epicardial coronary or microvascular spasm, endothelial dysfunction, and genetics as potentially contributing to the cascade of events leading to the onset. These pathomechanisms provide suggestions for novel potential therapeutic strategies in patients with TTS including the role of cognitive behavioural therapy, beta-blockers, and endothelin-A antagonists. The underlying mechanism of TTS remains elusive. In reality, physical or emotional stressors likely trigger through the amygdala and hippocampus a central neurohumoral activation with the local and systemic secretion of excess catecholamine and other neurohormones, which exert its effect on the myocardium through a metabolic switch, altered cellular signalling, and endothelial dysfunction. These complex pathways exert a regional activation in the myocardium through the altered distribution of adrenoceptors and density of autonomic innervation as a protective mechanism from myocardial apoptosis. More research is needed to understand how these different complex mechanisms interact with each other to bring on the TTS phenotype.

Investigating changes in β-adrenergic gene expression (ADRB1 and ADRB2) in Takotsubo (stress) cardiomyopathy syndrome; a pilot study

Background

Takotsubo Cardiomyopathy (TC) is a rare disorder that is mostly caused by stress and is often misdiagnosed. We aimed to analyze Takotsubo Syndrome at the molecular level by using the Oxford Nanopore Minion Device and its protocol.

Methods and results

Ten patients who were previously diagnosed with Takotsubo Syndrome (increased after decrease in ejection fraction and without critical stenosis in coronary arteries) and 10 healthy individuals in the control group were included in our project. The mean age was 53 ± 12.2 for the patient group and 52.4 ± 9.9 for the control group, and the left ventricular ejection fraction was 50.3 ± 11.5 for the patient group and 64.2 ± 2.8 for the control group (p < 0.05). Peripheral blood of patients and healthy individuals was taken and their DNA was obtained. By making long reads throughout the genome, the most studied regions responsible for β-adrenergic signaling pathways; The gene expression level of cardiac β-1 ADRB1 (rs1801253-ENST00000369295.4), G > C, (Gly389Arg) and cardiac β-2 ADRB2 (rs1800888-ENSG00000169252), C > T, (Thr165Ile) adrenoceptors was investigated. As a result; no structural variation was detected leading to Takotsubo Cardiomyopathy. The results obtained from the bioinformatics analysis were also checked from the VarSome Tools and similar results were found.

Conclusions

Many publications in TC susceptibility have that may lead to adrenergic pathway dysregulation, most studied adrenergic receptor genes in the similar literatures too. We searched for genetic variants in b1AR and b2AR genes in our study and however we could not find any variants in this study, we think larger numbers of cohort studies are needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-021-06816-w.

Genetic and Epigenetic Factors of Takotsubo Syndrome: A Systematic Review

Takotsubo syndrome (TTS), recognized as stress's cardiomyopathy, or as left ventricular apical balloon syndrome in recent years, is a rare pathology, described for the first time by Japanese researchers in 1990. TTS is characterized by an interindividual heterogeneity in onset and progression, and by strong predominance in postmenopausal women. The clear causes of these TTS features are uncertain, given the limited understanding of this intriguing syndrome until now. However, the increasing frequency of TTS cases in recent years, and particularly correlated to the SARS-CoV-2 pandemic, leads us to the imperative necessity both of a complete knowledge of TTS pathophysiology for identifying biomarkers facilitating its management, and of targets for specific and effective treatments. The suspect of a genetic basis in TTS pathogenesis has been evidenced. Accordingly, familial forms of TTS have been described. However, a systematic and comprehensive characterization of the genetic or epigenetic factors significantly associated with TTS is lacking. Thus, we here conducted a systematic review of the literature before June 2021, to contribute to the identification of potential genetic and epigenetic factors associated with TTS. Interesting data were evidenced, but few in number and with diverse limitations. Consequently, we concluded that further work is needed to address the gaps discussed, and clear evidence may arrive by using multi-omics investigations.

Pathophysiology of Takotsubo Syndrome as A Bridge to Personalized Treatment

Takotsubo syndrome (TTS) consists of transient dysfunction of the left and/or right ventricle in the absence of ruptured plaque; thrombus or vessel dissection. TTS may be divided into two categories. Primary TTS occurs when the cause of hospitalization is the symptoms resulting from damage to the myocardium usually preceded by emotional stress. Secondary TTS occurs in patients hospitalized for other medical; surgical; anesthetic; obstetric or psychiatric conditions who have activation of their sympathetic nervous system and catecholamines release- they develop TTS as a complication of their primary condition or its treatment. There are several hypotheses concerning the cause of the disease. They include a decrease in estrogen levels; microcirculation dysfunction; endothelial dysfunction and the hypothesis based on the importance of the brain-heart axis. More and more research concerns the importance of genetic factors in the development of the disease. To date; no effective treatment or prevention of recurrent TTS has been found. Only when the pathophysiology of the disease is fully known; then personalized treatment will be possible.

Perioperative takotsubo cardiomyopathy: Implications for anesthesiologist

Takotsubo cardiomyopathy (TCM) is characterized by transient ventricular dysfunction in the absence of obstructive coronary artery disease that may be triggered by an acute medical illness or intense physical or emotional stress. TCM is often confused with acute myocardial infarction given the similar electrocardiographic changes, cardiac enzymes, hemodynamic perturbations, and myocardial wall motion abnormalities. In the perioperative setting, the clinical picture may be more confusing because of the effect of anesthesia as well as hemodynamic changes related to the surgery itself. However, awareness of various other diagnostic modalities may enable clinicians to distinguish between the two, more systematically and with greater certainty. Despite the large body of literature, there still seems to be an overall paucity in our understanding of the etiopathogenesis, clinical characteristics, natural history, and management of this syndrome, especially in the perioperative setting. This narrative review seeks to present and synthesize the most recent literature on TCM and to identify gaps in current knowledge which can become the basis for future research.

An Emerging Cardiovascular Disease: Takotsubo Syndrome

Takotsubo syndrome (TTS) is a recently identified cardiac disease, which is far from being completely known. The aims of this narrative review are to provide a better understanding of the pathophysiological features of TTS and to update clinical findings in order to improve the management of subjects affected by this syndrome (according to the most recent consensus papers issued by the international scientific societies). We based our search on the material obtained via PubMed up to April 2019. The terms used were "Takotsubo Syndrome and Takotsubo cardiomyopathy" in combination with "heart failure, pathophysiology, complications, diagnosis, and treatment." TTS is a reversible form of ventricular dysfunction usually characterized by akinesia of the apex in the absence of obstructive coronary artery disease. In its initial phase, TTS may be indistinguishable from AMI and is usually triggered by a sudden emotional/physical stressor which abruptly increases catecholamine levels. However, the mechanisms by which catecholamines or other unidentified molecules can cause myocardial dysfunction is unknown. In-hospital stay may be hampered by various life-threatening complications, while data on long-term survival remain scarce and unclear. Furthermore, TTS may sometimes recur. We believe that TTS is clearly a much more complex condition than previously thought. Much remains to be discovered about its pathophysiologic mechanisms, the role of the link between the heart and brain and that of triggering factors and gender, and the reasons why this syndrome displays different phenotypes and sometimes recurs. Undoubtedly, preliminary evidence from pathophysiological studies (mainly genetic studies) has shown promising advances. However, prospective randomized clinical trials are still needed in order to identify and to tailor the best medical treatments for TTS patients.

Takotsubo twins

Takotsubo syndrome is an intriguing condition of often stress induced reversible cardiac dysfunction mimicking myocardial infarction, but without explanatory coronary obstructions. The pathogenesis of the syndrome is not yet fully understood, though altered sympathetic regulation or response to cardiac sympathetic stimuli is likely to be involved. We present a unique and clinically detailed report of identical twin sisters, who both developed Takotsubo syndrome in association to mental stress shortly after menopause, also covering a potential relapse of disease in one of the twins, supporting the theory of a genetic contribution to the development of the syndrome proposed by previous case reports and small genetic studies.

Takotsubo syndrome: State-of-the-art review by an expert panel - Part 1

Takotsubo syndrome (TTS) is an acute cardiac condition independent of epicardial coronary obstruction that mimics acute coronary syndrome and is characterized by acute heart failure with reversible ventricular motion abnormalities. This consensus paper is the result of a multinational effort aiming to summarize the current state of the art on TTS. Experts in the field provide a thorough and detailed review of this syndrome. Several novel and unique sections are emphasized in this document, including the current state of the art on genetics of takotsubo syndrome, microRNAs (miRs), racial differences, role of cardiac spectroscopy and intracoronary imaging, as well as mechanical circulatory support. In part 1 of this two-part manuscript, we discuss how TTS came to be known, several patterns and forms it can take in patients, epidemiology and pathophysiology of the syndrome, and clinical presentation.

Copy number variants implicate cardiac function and development pathways in earthquake-induced stress cardiomyopathy

The pathophysiology of stress cardiomyopathy (SCM), also known as takotsubo syndrome, is poorly understood. SCM usually occurs sporadically, often in association with a stressful event, but clusters of cases are reported after major natural disasters. There is some evidence that this is a familial condition. We have examined three possible models for an underlying genetic predisposition to SCM. Our primary study cohort consists of 28 women who suffered SCM as a result of two devastating earthquakes that struck the city of Christchurch, New Zealand, in 2010 and 2011. To seek possible underlying genetic factors we carried out exome analysis, genotyping array analysis, and array comparative genomic hybridization on these subjects. The most striking finding was the observation of a markedly elevated rate of rare, heterogeneous copy number variants (CNV) of uncertain clinical significance (in 12/28 subjects). Several of these CNVs impacted on genes of cardiac relevance including RBFOX1, GPC5, KCNRG, CHODL, and GPBP1L1. There is no physical overlap between the CNVs, and the genes they impact do not appear to be functionally related. The recognition that SCM predisposition may be associated with a high rate of rare CNVs offers a novel perspective on this enigmatic condition.

Genetics of Takotsubo Syndrome

Takotsubo syndrome (TTS) is an enigmatic disease with a multifactorial and still unresolved pathogenesis. A genetic predisposition has been suggested based on the few familial TTS cases. Conflicting results have been published regarding the role of functional polymorphisms in relevant candidate genes, such as α1-, β1-, and β2-adrenergic receptors; G protein-coupled receptor kinase 5; and estrogen receptors. Further research is required to help clarify the role of genetic susceptibility in TTS.

Broken heart, tako-tsubo or stress cardiomyopathy? Metaphors, meanings and their medical impact

The cardiac impact of psychological stress historically and socially understood as boundary experiences of human life has long since become an icon. From the aching heart to the sudden death provoked by awe, horror, grief, anger, and humiliation on one side and extreme enchantment, enthusiasm, and excitement on the other, the broken heart has become a globally recognized and powerful metaphor present from folklore to popular culture to high literature and back to everyday communication. In medicine, the "broken heart syndrome" is described as a relatively new nosological entity that has been used synonymously with the term tako-tsubo or stress cardiomyopathy. Among those three terms, however, the broken heart most vividly draws the connection between conditions under which lived experience triggers cardiac damage and conversely, cardiovascular death occurs. According to Hassan and Yamasaki (2013) [1] and quite apart from the general perception medical notions of the broken heart indeed go back to at least 1967, when Rees and Lutkins studied the death rate among 903 relatives of patients who died in Wales. They found that 4.8% of bereaved close relatives died within a year of bereavement compared with 0.68% of a non-bereaved control group. Among widows and widowers, the mortality rate was even 10 times greater than that of the matched controls. After the first year of bereavement, however, mortality rates of relatives of a deceased person did not differ significantly from the control group Rees and Lutkins (1967) [2]. Similar findings were published by Parkes et al. (1969) [3] following up on 4486 widowers at the age of 55 for 9years following the death of their wives in 1957. During the first six months after the spouse had died, the mortality rate of the widowers was 40% above the rate of married men of the same age. While it seems plausible to accept the etiological role and pathogenic impact of personal loss, the pathogenic processes causing death remained relatively blurred. We will explain, why inaccurately stressing the fact that the broken heart and/or tako-tsubo syndrome would be a relatively new way of looking at stress-related cardiomyopathy as outlined by Yoshikawa (2015) [4] and why attaching stress-related cardiomyopathy to culturally powerful yet value-laden metaphors, might obstruct pathways to a better understanding, prevention and clinical management of the disease. By looking at narrative understandings and clinical representations of the broken heart, we aim to highlight the need for a more contextualised view of the broken heart syndrome in order to facilitate multi- and transdisciplinary approaches aiming at its prediction, prevention, and treatment.

Genome-wide association study in takotsubo syndrome - Preliminary results and future directions

BACKGROUND

Takotsubo syndrome (TS) is an acute non-ischemic cardiomyopathy characterized by transient regional systolic dysfunction of the left and/or right ventricle with still unknown etiology. The aim of the current study was to conduct for the first time a genome-wide association study (GWAS) in a cohort of TS patients to identify potential genetic risk variants.

METHODS

This single-center study was conducted at the University Heart Center Lübeck from 2008 to 2016. DNA isolation was done according to standard protocols. Imputation of genotypes were performed at the Michigan Imputation Server (https://imputationserver.sph.umich.edu) using the 1000G Phase 3 v5 reference panel.

RESULTS

The study population consisted of 96 TS patients (91 females, 5 males) with a mean age of 71.9±10.4years and 475 healthy controls (268 males, 207 females). The results of GWAS analysis showed several promising candidate loci (68 loci after applying threshold of p<5∗10^-4 and MAF>5%). Of these 68 loci, 18 loci contained top single nucleotide polymorphisms (SNPs) that were supported by SNPs in high Linkage Disequilibrium (r2>0.8) with p<10^-3. Two out of the 18 loci contained SNP with hits in the GWAS catalog (traits: blood pressure, thyroid stimulating hormone).

CONCLUSION

This first GWAS analysis in a larger cohort of patients with TS showed promising preliminary results. Further intensive research efforts of international collaborators are now necessary to enable deep-phenotyping of TS patients to ultimately assess a potential genetic cause of TS.

Takotsubo Cardiomyopathy: Typical and Atypical Variants, A Two-Year Retrospective Cohort Study

Background

Typical or classical takotsubo cardiomyopathy (TCM) is associated with the characteristic abnormality of a ballooned left ventricular apex with basal segmental hyperkinesis. TCM may not present with the “classical” wall motion abnormalities but can have a variety of segmental wall motion abnormalities. The aim of our work was to assess for any unique identifying factors that can help distinguish typical and atypical variants of TCM.

Methods

We studied 11 consecutive patients between 2010 and 2012 admitted with chest pain, electrocardiographic and cardiac biomarker changes consistent with acute coronary syndrome (ACS) who underwent left heart angiography and were clinically diagnosed to have TCM.

Results

Our study found no specific features distinguishing typical and atypical variants of TCM. In our study, all patients were female and all had excellent outcome. One patient was in fourth decade of life, three patients in fifth and sixth decade of life, while remaining were older. One patient had diabetes mellitus, five had hypertension, four had concurrent coronary artery disease, but no patient had any family history of TCM. Nine of 11 patients had immediate clear-cut stressors. Three patients had normal ECG, two with ST segment elevation, with nine patients having only modest troponin elevations. One patient had an anomalous RCA take-off from the right coronary cusp, otherwise remaining patients had normal anatomy. One patient had only apical involvement, remaining had multiple wall motion abnormalities, and all patients had involvement of the anterior wall. Four patients had apical sparing. No inverted TCM pattern with basal akinesis with normal wall motion in the midventricular and apical regions was found among our patients.

Conclusions

We report that the classification of TCM as typical versus atypical is probably not clinically meaningful. The regional wall motion abnormalities are related to catecholamine excess and to the susceptibility of that particular region to excess catecholamine. We do not know why such differences in regional susceptibility exist, and agree with the other authors that sub-classification would only add to confusion, and a delay in understanding of the disease process.

Characterizing genetic variation of adrenergic signalling pathways in Takotsubo (stress) cardiomyopathy exomes

AIMS

Exome sequencing was used to genotype comprehensively a Takotsubo (stress) cardiomyopathy (TC) cohort, enabling investigation of a vast 486 gene network for adrenergic signalling.

METHODS AND RESULTS

Twenty-eight TC subjects, including a mother-daughter pair and five recurrent cases, underwent whole-exome sequencing. Frequencies of 17 common, functional adrenergic polymorphisms were statistically similar to those of population controls. Filtering for rare, predicted-deleterious, catecholamine/adrenergic signalling variants revealed heterozygosity in 55 genes in TC cases and 59 genes in healthy controls. Overall allele burden was similar and did not discriminate clinical variables among TC subjects, but gene identities were largely cohort specific, and TC cases were enriched for variants within functional domains (68% vs. 48%, P = 0.031). Two-thirds of TC cases carried more than one filtered adrenergic pathway variant, and 11 genes harboured a variant in ≥ 2 cases. The mother-daughter pair shared missense variants in highly conserved functional domains of ADH5, CACNG1, EPHA4, and PRKCA. An adrenergic pathway-independent analysis of the cohort exposed no common gene for TC.

CONCLUSIONS

Overall, these data support genetic heterogeneity in TC susceptibility and a likely polygenic basis, conferring a cumulative effect on adrenergic pathway dysregulation in a subset of individual subjects. Study of larger cohorts and non-coding regulatory regions is warranted to define genetic risk factors for TC further.