Role of serotoninergic pathways in drug-induced valvular heart disease and diagnostic features by echocardiography

Case Report: unexpected cause of cyanosis in an infant after acute exposure to high altitude-severe tricuspid regurgitation secondary to tricuspid valve prolapse

Background

Severe tricuspid regurgitation (TR) causing cyanosis with patent foramen ovale (PFO) and right-to-left atrial shunting requires a precise diagnosis for optimal therapy. Tricuspid valve prolapse (TVP) can lead to TR and is sometimes overlooked, especially in complex cases with factors like pulmonary hypertension (PH). We present an infant with cyanosis and profound TR after high-altitude exposure, initially misattributed to PH but found to be primarily due to spontaneous chordae tendineae rupture and TVP. This case underscores the challenges in diagnosing TR-induced cyanosis.

Case presentation

The 3-month-old infant rapidly developed cyanosis, hypoxemia, right atrial enlargement, severe tricuspid regurgitation (TR), and patent foramen ovale (PFO) shunting after high-altitude exposure. Although echocardiography revealed tricuspid valve prolapse (TVP), initial consideration linked TR and right-to-left shunting to pulmonary hypertension (PH) due to the temporal correlation with rapid altitude exposure. Despite hemodynamic stability and the absence of respiratory distress after respiratory support and combined PH medication therapy, the persistent hypoxemia did not reverse as expected. This treatment outcome and repeated echocardiograms reminded us that TR was primarily caused by TVP rather than PH alone. Intraoperative exploration confirmed that TVP was caused by a rupture of TV chordae tendineae and anterior papillary muscle head, and the chordae tendineae/papillary muscle connection was reconstructed. After surgery, this patient was noncyanotic with an excellent long-term prognosis, a trivial TR with normal TV function being observed echocardiographically.

Conclusions

TR-induced cyanosis can be not only a consequence of PH and right-sided heart dilation but also a primary condition. Repetitive reassessment should be undertaken with caution, particularly when patients are not improving on therapy in the setting of conditions known to predisposition to secondary TR. Since TVP caused by rupture of the chordae or papillary muscles is rare but fatal in children, early diagnosis is clinically substantial to proper management and satisfactory long-term outcomes.

Microdosing psychedelics and the risk of cardiac fibrosis and valvulopathy: Comparison to known cardiotoxins

Though microdosing psychedelics has become increasingly popular, its long-term effects on cardiac health remain unknown. Microdosing most commonly involves ingesting sub-threshold doses of lysergic acid diethylamide (LSD), psilocybin, or other psychedelic drugs 2-4 times a week for at least several weeks, but potentially months or years. Concerningly, both LSD and psilocybin share structural similarities with medications which raise the risk of cardiac fibrosis and valvulopathy when taken regularly, including methysergide, pergolide, and fenfluramine. 3,4-Methylenedioxymethamphetamine, which is also reportedly used for microdosing, is likewise associated with heart valve damage when taken chronically. In this review, we evaluate the evidence that microdosing LSD, psilocybin, and other psychedelics for several months or more could raise the risk of cardiac fibrosis. We discuss the relationship between drug-induced cardiac fibrosis and the 5-HT2B receptor, and we make recommendations for evaluating the safety of microdosing psychedelics in future studies.

A Happy Patient Sheltering an Unhappy Valve: Serotonin Reuptake Inhibitor-Induced Tricuspid Valve Regurgitation

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Drug-induced valvular heart disease (DI-VHD) is reminiscent of carcinoid heart disease.

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DI-VHD is mediated through 5-hydroxytryptamine 2β receptor signaling pathways.

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Serotonergic agents interacting with this 2β receptor may cause carcinoid-like VHD.

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DI-VHD must be considered in patients with no reasons for showing VHD and using SSRI.

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Echocardiographic surveillance is warranted in patients on serotonergic drugs, including SSRI.

The human endogenous metabolome as a pharmacology baseline for drug discovery

We have limited understanding of the variation in in vitro affinities of drugs for their targets. An analysis of a highly curated set of 815 interactions between 566 drugs and 129 primary targets reveals that 71% of drug-target affinities have values above that of the corresponding endogenous ligand, 96% of them fitting within a range of two orders of magnitude. Our findings suggest that the evolutionary optimised affinity of endogenous ligands for their native proteins can serve as a baseline for the primary pharmacology of drugs. We show that the degree of off-target selectivity and safety risks of drugs derived from their secondary pharmacology depend very much on that baseline. Thus, we propose a new approach for estimating safety margins.

Antidepressants and Valvular Heart Disease: A Nested Case-Control Study in Taiwan

Empirical evidence regarding the association between antidepressants and valvular heart disease (VHD) is scarce.Using Taiwan's National Health Insurance Research database, this nested case-control study assessed the association between antidepressants and VHD in a Chinese population.Among a cohort of patients who used at least 3 prescription antidepressants, 874 cases with VHD and 3496 matched controls (1:4 ratio) were identified. Conditional logistic regression models were used to examine the timing, duration, dose and type of antidepressants use, and the risk of VHD.Current use of antidepressants was associated with a 1.4-fold increase in the risk of VHD (adjusted odds ratio [aOR] 1.44; 95% confidence interval [CI] 1.17-1.77). Among current users, a dose-response association was observed in terms of the cumulative duration and the cumulative antidepressant dose. Significantly higher risks of VHD were observed among the current users of tricyclic antidepressants (aOR 1.40 [1.05-1.87]).We found that the use of antidepressants was associated with a greater risk of VHD and that the risks varied according to different antidepressants.

A happy valve in a happy patient? Serotonergic antidepressants and the risk of valvular heart disease (SERVAL). A case-control study

OBJECTIVES

The objective was to investigate the risk of valvular heart disease in humans in relation to the use of selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors.

DESIGN

A case-control study. We conducted a case-control study within this cohort in which patients with newly diagnosed cardiac valve regurgitation were age-matched to controls. Patient demographics, their cardiovascular risk factors and medication use were extracted in both series. Use of SSRIs, serotonin and noradreline reuptake inhibitors (SNRIs) and other pro-serotonergic agents, their dose and treatment duration were recorded. Logistic regression analysis was used to establish the strength of the association between SSRI/SNRI use and valvular heart disease.

SETTING

Outpatient clinic of the cardiology department at the Ghent University Hospital, East-Flanders in Belgium.

PARTICIPANTS

Total of 2911 persons 21-58 years of age who had undergone an echocardiogram in the period 2006-2010 and had no known cardiovascular disease or previous cardiac intervention. Two hundred and six echocardiographically proven cases of valvular regurgitation and 195 matched controls.

MAIN OUTCOME MEASURE

Odd ratio of valvular disease associated with intake of serotonergic drugs.

RESULTS

Of the 206 patients with newly diagnosed cardiac valve regurgitation, 11.6% were exposed to serotonergic agents compared to 4.1% in the 195 control patients, leading to an odds ratio of 3.08 (95% confidence interval [CI] 1.35-7.04). The analysis of doses and treatment durations revealed a dose-relationship pattern between SSRI/SNRI use and prevalent valvular heart disease.

CONCLUSIONS

In this study, use of serotonergic antidepressants was associated with an increased rate of valvular regurgitation in humans.

The need for annual echocardiography to detect cabergoline-associated valvulopathy in patients with prolactinoma: a systematic review and additional clinical data

Present recommendations by the US Food and Drug Administration advise that patients with prolactinoma treated with cabergoline should have an annual echocardiogram to screen for valvular heart disease. Here, we present new clinical data and a systematic review of the scientific literature showing that the prevalence of cabergoline-associated valvulopathy is very low. We prospectively assessed 40 patients with prolactinoma taking cabergoline. Cardiovascular examination before echocardiography detected an audible systolic murmur in 10% of cases (all were functional murmurs), and no clinically significant valvular lesion was shown on echocardiogram in the 90% of patients without a murmur. Our systematic review identified 21 studies that assessed the presence of valvular abnormalities in patients with prolactinoma treated with cabergoline. Including our new clinical data, only two (0·11%) of 1811 patients were confirmed to have cabergoline-associated valvulopathy (three [0·17%] if possible cases were included). The probability of clinically significant valvular heart disease is low in the absence of a murmur. On the basis of these findings, we challenge the present recommendations to do routine echocardiography in all patients taking cabergoline for prolactinoma every 12 months. We propose that such patients should be screened by a clinical cardiovascular examination and that echocardiogram should be reserved for those patients with an audible murmur, those treated for more than 5 years at a dose of more than 3 mg per week, or those who maintain cabergoline treatment after the age of 50 years.

The use of antidepressants and the risk of chronic atrial fibrillation

Serotonin stimulation of the 5HT4 receptor might be responsible for an increased risk of atrial fibrillation (AF). Thus, we assessed whether the use of antidepressants (ADs) is associated with an increased risk of chronic AF (cAF). Using the UK Clinical Practice Research Datalink, a nested case-control analysis was conducted within a cohort of new AD users having a diagnosis of depression and/or anxiety. Cases of cAF occurring during follow-up were individually matched with up to 10 controls on age, sex, year of cohort entry, and duration of follow-up. Conditional logistic regression was used to estimate rate ratios (RRs) and 95% confidence intervals (CIs) of cAF associated with current and recent use of ADs, when compared to past use. The cohort included 116,125 new AD users, of whom 1,271 were diagnosed with cAF during follow-up (incidence rate: 1.6 per 1,000 person-years). The adjusted RR of cAF associated with current and recent use of ADs was 0.98 (95%CI: 0.86-1.12) and 1.02 (95%CI: 0.86-1.30), respectively. No association was observed when ADs were classified according to their potency in reducing serotonin reuptake. These findings suggest that exposure to ADs is not associated with an increased risk of cAF.

Structure and function of serotonin G protein-coupled receptors

Serotonin receptors are prevalent throughout the nervous system and the periphery, and remain one of the most lucrative and promising drug discovery targets for disorders ranging from migraine headaches to neuropsychiatric disorders such as schizophrenia and depression. There are 14 distinct serotonin receptors, of which 13 are G protein-coupled receptors (GPCRs), which are targets for approximately 40% of the approved medicines. Recent crystallographic and biochemical evidence has provided a converging understanding of the basic structure and functional mechanics of GPCR activation. Currently, two GPCR crystal structures exist for the serotonin family, the 5-HT1B and 5-HT2B receptor, with the antimigraine and valvulopathic drug ergotamine bound. The first serotonin crystal structures not only provide the first evidence of serotonin receptor topography but also provide mechanistic explanations into functional selectivity or biased agonism. This review will detail the findings of these crystal structures from a molecular and mutagenesis perspective for driving rational drug design for novel therapeutics incorporating biased signaling.

Ergotamine and nicergoline - facts and myths

Ergotamine, being a representative of naturally occurring ergoline alkaloids, derived from d-lysergic acid, and nicergoline, a d-lumilysergic acid derivative belonging to semi-synthetic ergot-derived alkaloids, display diversified affinity for adrenergic, serotoninergic, and dopamine receptors. Although introduction of triptans marginalized use of ergotamine, nicergoline is used in cerebral metabolic-vascular disorders, and dementia. Additionally, nicergoline exhibits a safety profile comparable to that of placebo, and none of the reviewed studies reported any incidence of fibrosis or ergotism with nicergoline treatment. In line with the recent data, activation of 5-HT2B receptor by ergot derivatives i.e. ergotamine, methysergide, pergolide, and carbegoline is involved in pathogenesis of drug-induced valvulopathy. In contrary structurally related drugs - lisuride and terguride do not increase the risk of valvular heart disease. It seems, that more detailed mechanistic studies on nicergoline and ergotamine might be beneficial for determining structural requirements related to activation of G-protein as well as alternative signal transduction pathways e.g. β-arrestins or different kinases, and responsible for drug liabilities.

Cardiac manifestations of gastrointestinal carcinoid tumor

Carcinoid tumors are rare, slow-growing tumors found primarily in the GI tract. Carcinoid syndrome develops when vasoactive substances (particularly serotonin) released by carcinoid tumors gain access to the systemic circulation. Carcinoid heart disease develops in patients with carcinoid syndrome and is commonly associated with the development of right-sided valve dysfunction and signs of symptoms of right heart failure. Timely surgical intervention provides relief from symptoms and may improve survival. Management of these patients should be undertaken in a specialized center by a multidisciplinary team with appropriate expertise.

Predictive in silico studies of human 5-hydroxytryptamine receptor subtype 2B (5-HT2B) and valvular heart disease

Serotonin (5-hydroxytryptamine, 5-HT) receptors are neuromodulator neurotransmitter receptors which when activated trigger a signal transduction cascade within cells resulting in cell-cell communication. 5-hydroxytryptamine receptor 2B (5-HT2B) is a subtype of the seven members of 5-hydroxytrytamine receptors family which is the largest member of the super family of 7-transmembrane G-protein coupled receptors (GPCRs). Not only do 5-HT receptors play physiological roles in the cardiovascular system, gastrointestinal and endocrine function as well as the central nervous system, but they also play a role in behavioral functions. In particular 5-HT2B receptor is widely spread with regards to its distribution throughout bodily tissues and is expressed at high levels in the lungs, peripheral tissues, liver, kidneys and prostate, just to name a few. Hence 5-HT2B participates in multiple biological functions including CNS regulation, regulation of gastrointestinal motality, cardiovascular regulation and 5-HT transport system regulation. While 5-HT2B is a viable drug target and has therapeutic indications for treating obesity, psychosis, Parkinson's disease etc. there is a growing concern regarding adverse drug reactions, specifically valvulopathy associated with 5-HT2B agonists. Due to the sequence homology experienced by 5-HT2 subtypes there is also a concern regarding the off-target effects of 5-HT2A and 5-HT2C agonists. The concepts of sensitivity and subtype selectivity are of paramount importance and now can be tackled with the aid of in silico studies, especially cheminformatics, to develop models to predict valvulopathy associated toxicity of drug candidates prior to clinical trials. This review has highlighted three in silico approaches thus far that have been successful in either predicting 5-HT2B toxicity of molecules or identifying important interactions between 5-HT2B and drug molecules that bring about valvulopathy related toxicities.

Use of antidepressant serotoninergic medications and cardiac valvulopathy: a nested case-control study in the health improvement network (THIN) database

AIMS

To quantify the risk of cardiac valvulopathy (CV) associated with the use of antidepressant serotoninergic medications (SMs).

METHODS

We conducted a case-control study nested in a cohort of users of antidepressant SMs selected from The Health Improvement Network database. Patients who experienced a CV event during follow-up were cases. Cases were ascertained in a random sample of them. Up to 10 controls were matched to each case by sex, age, month and year of the study entry. Use of antidepressant SMs during follow-up was defined as current (the last prescription for antidepressant SMs occurred in the 2 months before the CV event), recent (in the 2-12 months before the CV event) and past (>12 months before the CV event). We fitted a conditional regression model to estimate the association between use of antidepressant SMs and the risk of CV by means of odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Sensitivity analyses were conducted to test the robustness of our results.

RESULTS

The study cohort included 752,945 subjects aged 18-89 years. Throughout follow-up, 1663 cases (incidence rate: 3.4 per 10,000 person-years) of CV were detected and were matched to 16,566 controls. The adjusted OR (95% CI) for current and recent users compared with past users of antidepressant SMs were 1.16 (0.96-1.40) and 1.06 (0.93-1.22), respectively. Consistent effect estimates were obtained when considering cumulative exposure to antidepressant SMs during follow-up.

CONCLUSIONS

These results would suggest that exposure to antidepressant SMs is not associated with an increased risk of CV.

Devices in the management of advanced, chronic heart failure

Heart failure (HF) is a global phenomenon, and the overall incidence and prevalence of the condition are steadily increasing. Medical therapies have proven efficacious, but only a small number of pharmacological options are in development. When patients cease to respond adequately to optimal medical therapy, cardiac resynchronization therapy has been shown to improve symptoms, reduce hospitalizations, promote reverse remodelling, and decrease mortality. However, challenges remain in identifying the ideal recipients for this therapy. The field of mechanical circulatory support has seen immense growth since the early 2000s, and left ventricular assist devices (LVADs) have transitioned over the past decade from large, pulsatile devices to smaller, more-compact, continuous-flow devices. Infections and haematological issues are still important areas that need to be addressed. Whereas LVADs were once approved only for 'bridge to transplantation', these devices are now used as destination therapy for critically ill patients with HF, allowing these individuals to return to the community. A host of novel strategies, including cardiac contractility modulation, implantable haemodynamic-monitoring devices, and phrenic and vagus nerve stimulation, are under investigation and might have an impact on the future care of patients with chronic HF.

Carcinoid heart disease

Carcinoid tumors are rare, indolent neuroendocrine tumors that are often associated with a syndrome characterized by episodic flushing, secretory diarrhea, bronchospasm, and hypotension-the carcinoid syndrome. Cardiac involvement occurs in one-half to two-thirds of patients with carcinoid syndrome and is associated with a worse clinical outcome. Carcinoid heart disease is characterized by endocardial plaque-like deposits found predominantly on right-sided heart valves, leading to the combination of valvular stenosis and regurgitation. Left-sided cardiac involvement can also occur in <10% of patients. Somatostatin analogs form the therapeutic cornerstone in the medical management of these patients. Cytotoxic chemotherapy has had only limited success in the treatment of metastatic carcinoid tumors. Hepatic resection or palliative cytoreduction may be of benefit in patients with limited hepatic disease. Hepatic artery embolization is usually applied if a patient is not eligible for surgical debulking. The development and progression of carcinoid heart disease are associated with an unfavorable outcome. In those patients having severe cardiac involvement and well-controlled systemic disease, valve replacement surgery has been found to be an effective treatment that can both relieve intractable symptoms and contribute to improved clinical outcomes.

Occurrence of left-sided heart valve involvement before right-sided heart valve involvement in carcinoid heart disease

Carcinoids are rare neuroendocrine tumours that occur primarily in the gastrointestinal tract. Carcinoid heart disease is characterized by fibrous plaque deposition on the endocardial surface of the cardiac valves and chambers. It affects the right heart valves in 85% of cases and the left heart valves in 15%. We present an unusual case of a patient with metastatic carcinoid heart disease in whom typical carcinoid aortic and mitral valve lesions developed 2 years prior to the development of severe right-sided carcinoid valvular heart disease.