Hypertrophic cardiomyopathy: the future of treatment

Cardiac Myosin Inhibitors for Obstructive Hypertrophic Cardiomyopathy: A Meta-analysis of Randomized Placebo-Controlled Trials

BACKGROUND

Cardiac myosin inhibitors (CMI) have emerged as the first disease-specific, noninvasive therapy with promising results in patients with hypertrophic cardiomyopathy. However, its role in obstructive hypertrophic cardiomyopathy (oHCM) remains uncertain, especially in secondary endpoints of randomized controlled trials (RCTs).

METHODS

We systematically searched PubMed, Embase, Web of Science, and Clinicaltrials.gov from inception to June 2024 for RCTs comparing CMI versus placebo in patients with oHCM. We applied a random-effects model to evaluate efficacy and safety outcomes and primary or secondary outcomes of RCTs.

RESULTS

We included five RCTs comprising 767 patients, of whom 402 (52.5%) were randomized to CMI. Relative to placebo, CMI were associated with a higher rate of improvement of at least one New York Heart Association (NYHA) functional class [risk ratio (RR) 2.33; 95% confidence interval (CI) 1.92-2.82]. In addition, CMI reduced resting left ventricular outflow tract (LVOT) [mean difference (MD) - 42.51 mmHg; 95% CI - 59.27 to - 25.75] and the provoked LVOT gradients (MD - 46.12 mmHg; 95% CI - 55.70 to - 36.54). However, CMI significantly increased the risk of reaching a left ventricular ejection fraction below 50% (RR 4.80; 95% CI 1.42-16.20), affecting 8% of patients during long-term follow-up of up to 120 weeks. There was no significant interaction across subgroups of class representatives, pointing to a class effect. The benefit-risk analysis indicated a larger benefit for NYHA class improvement than risk for systolic dysfunction.

CONCLUSION

In patients with oHCM, mavacamten and aficamten as a class improve clinical and hemodynamic endpoints compared with placebo, albeit with a higher incidence of a reduction in left ventricular ejection fraction.

REGISTRATION

PROSPERO CRD42023468079.

Loss of quality of life and increased societal costs in patients with hypertrophic cardiomyopathy: the AFFECT-HCM study

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiac disease. The impact of HCM on quality of life (QoL) and societal costs remains poorly understood. This prospective multi-centre burden of disease study estimated QoL and societal costs of genotyped HCM patients and genotype-positive phenotype-negative (G+/P-) subjects.

METHODS AND RESULTS

Participants were categorized into three groups based on genotype and phenotype: (i) G+/P- [left ventricular (LV) wall thickness <13 mm], (ii) non-obstructive HCM [nHCM, LV outflow tract (LVOT) gradient <30 mmHg], and (iii) obstructive HCM (oHCM, LVOT gradient ≥30 mmHg). We assessed QoL with EQ-5D-5L and Kansas City Cardiomyopathy Questionnaires (KCCQ). Societal costs were measured using medical consumption (Medical Consumption Questionnaire) and productivity cost (iMTA Productivity Cost Questionnaire) questionnaires. We performed subanalyses within three age groups: <40, 40-59, and ≥60 years. From three Dutch hospitals, 506 subjects were enrolled (84 G+/P-, 313 nHCM, 109 oHCM; median age 59 years, 39% female). HCM (both nHCM and oHCM) patients reported reduced QoL vs. G+/P- subjects (KCCQ: 88 vs. 98, EQ-5D-5L: 0.88 vs. 0.96; both P < 0.001). oHCM patients reported lower KCCQ scores than nHCM patients (83 vs. 89, P = 0.036). Societal costs were significantly higher in HCM patients (€19,035/year vs. €7385/year) compared with G+/P- controls, mainly explained by higher healthcare costs and productivity losses. Being symptomatic and of younger age (<60 years) particularly led to decreased QoL and increased costs.

CONCLUSION

HCM is associated with decreased QoL and increased societal costs, especially in younger and symptomatic patients. oHCM patients were more frequently symptomatic than nHCM patients. This study highlights the substantial disease burden of HCM and can aid in assessing new therapy cost-effectiveness for HCM in the future.

KLF9 aggravates the cardiomyocyte hypertrophy in hypertrophic obstructive cardiomyopathy through the lncRNA UCA1/p27 axis

Cardiac hypertrophy refers to an abnormal increase in the thickness of the heart muscle. Our study explores the role of Krüppel-like factor 9 (KLF9) in hypertrophic obstructive cardiomyopathy (HOCM)-induced cardiomyocyte hypertrophy, providing new targets for the treatment of HOCM. Cardiomyocytes were treated with isoproterenol (ISO). The levels of natriuretic peptide B (BNP)/natriuretic peptide A (ANP)/KLF9/long non-coding RNA urothelial carcinoma-associated 1 (lncRNA UCA1)/p27 were measured. Cell surface area and protein/DNA ratio were tested. The binding between KLF9 and the lncRNA UCA1 promoter and between zeste homologue 2 (EZH2) and lncRNA UCA1 was verified. The enrichment of histone H3 lysine 27 tri-methylation (H3K27me3) and EZH2 on the p27 promoter was analysed. ISO treatment increased KLF9 and lncRNA UCA1 expression and decreased p27 expression in cardiomyocytes. KLF9 knockdown inhibited ISO-induced cardiomyocyte hypertrophy, reduced ANP and BNP expression, and alleviated cardiomyocyte damage. KLF9 activated lncRNA UCA1 expression. LncRNA UCA1 recruited EZH2 to the p27 promoter region, increasing the enrichment of H3K27me3, thereby epigenetically suppressing p27 expression. LncRNA UCA1 overexpression or p27 downregulation reduced the protective effect of KLF9 downregulation on cardiomyocyte hypertrophy. In conclusion, KLF9 activates lncRNA UCA1 expression, and lncRNA UCA1 epigenetically suppresses p27 expression, thereby exacerbating cardiomyocyte hypertrophy in HOCM.

Genes Associated With Hypertrophic Cardiomyopathy: A Reappraisal by the ClinGen Hereditary Cardiovascular Disease Gene Curation Expert Panel

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac condition affecting ∼1 in 500 and exhibits marked genetic heterogeneity. Previously published in 2019, 57 HCM-associated genes were curated providing the first systematic evaluation of gene-disease validity.

OBJECTIVES

The authors report work by the Clinical Genome Resource Hereditary Cardiovascular Disease (HCVD) Gene Curation Expert Panel (GCEP) to reappraise the clinical validity of previously curated and new putative HCM genes.

METHODS

The Clinical Genome Resource systematic gene curation framework was used to reclassify the gene-disease relationships for HCM and related syndromic entities involving left ventricular hypertrophy. Genes previously curated were included if their classification was not definitive, and if the time since curation was >2 to 3 years. New genes with literature assertions for HCM were included for initial evaluation. Existing genes were curated for new inheritance patterns where evidence existed. Curations were presented on twice monthly calls, with the HCVD GCEP composed of 29 individuals from 21 institutions across 6 countries.

RESULTS

Thirty-one genes were recurated and an additional 5 new potential HCM-associated genes were curated. Among the recurated genes, 17 (55%) genes changed classification: 1 limited and 4 disputed (from no known disease relationship), 9 disputed (from limited), and 3 definitive (from moderate). Among these, 3 (10%) genes had a clinically relevant upgrade, including TNNC1, a 9th sarcomere gene with definitive HCM association. With new evidence, 2 genes were curated for multiple inheritance patterns (TRIM63, disputed for autosomal dominant but moderate for autosomal recessive; ALPK3, strong for autosomal dominant and definitive for recessive). CSRP3 was curated for a semidominant mode of inheritance (definitive). Nine (29%) genes were downgraded to disputed, further discouraging clinical reporting of variants in these genes. Five genes recently reported to cause HCM were curated: RPS6KB1 and RBM20 (limited), KLHL24 and MT-TI (moderate), and FHOD3 (definitive).

CONCLUSIONS

We report 29 genes with definitive, strong, or moderate evidence of causation for HCM or isolated left ventricular hypertrophy, including sarcomere, sarcomere-associated, and syndromic conditions.

Sigmoid Septum: A Bystander or Contributor to a Left Ventricular Outflow Tract Obstruction in Takotsubo Syndrome - A Case Report with a Literature Review

Approximately 20% of patients with Takotsubo syndrome (TTS) develop complications such as left ventricular outflow tract obstruction (LVOTO). The published data suggest that a significant proportion of these patients have predisposing septal hypertrophy or sigmoid septum. However, the pathophysiology regarding this connection has not yet been fully elucidated. We herein present the case of a 75-year-old female patient with TTS complicated by LVOTO, which was successfully managed. During the follow-up, mild basal septal hypertrophy was observed. Subsequent exercise and dobutamine stress echocardiography were performed to reveal the mechanism of LVOTO in TTS.

Whole exome sequence reveals genetic profiles of primary cardiomyopathy and genotype-phenotype association in Chinese population

BACKGROUND

Primary cardiomyopathies are major causes of heart failure, placing a substantial burden on both individuals and society. Revealing its genetic profiles can lead to a better understanding of the mechanism and is critical for disease prevention and treatment.

METHOD

Primary cardiomyopathy patients were enrolled and whole exome sequence was conducted to analyze their genetic profiles. Retrospective clinical information extraction and analysis of sequence data were implemented.

RESULTS

A total of 77 primary cardiomyopathy patients were enrolled, comprising 65 patients with dilated cardiomyopathy (DCM) and 12 with hypertrophic cardiomyopathy (HCM). Among the DCM patients, 13 variants classified as pathogenic (P) or likely pathogenic (LP) were identified in 12 patients (18.46%), predominantly in genes associated with the nuclear envelope and sarcomere. Among HCM patients, 6 P/LP variants were discovered in 6 (50%) patients. Taking variants of uncertain significance (VUS) into consideration, an analysis of the association between the number of variants carried by patients and their clinical characteristics revealed that DCM patients with more than one variant had a higher proportion of hyperuricemia.

CONCLUSIONS

We map a comprehensive profile of primary cardiomyopathy in Chinese population and, for the first time, identify a possible association between hyperuricemia and the number of genetic variants carried by DCM patients.

Hypertrophic Cardiomyopathy: Genes and Mechanisms

Hypertrophic cardiomyopathy (HCM) is a hereditary disease of the myocardium characterized by asymmetric hypertrophy (mainly the left ventricle) not caused by pressure or volume load. Most cases of HCM are caused by genetic mutations, particularly in the gene encoding cardiac myosin, such as MYH7, TNNT2, and MYBPC3. These mutations are usually inherited autosomal dominantly. Approximately 30-60% of HCM patients have a family history of similar cases among their immediate relatives. This underscores the significance of genetic factors in the development of HCM. Therefore, we summarized the gene mutation mechanisms associated with the onset of HCM and potential treatment directions. We aim to improve patient outcomes by increasing doctors' awareness of genetic counseling, early diagnosis, and identification of asymptomatic patients. Additionally, we offer valuable insights for future research directions, as well as for early diagnosis and intervention.

Recent Clinical Updates of Hypertrophic Cardiomyopathy and Future Therapeutic Strategies

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiomyopathy transmitted in an autosomal dominant manner to offspring. It is characterized by unexplained asymmetrical hypertrophy primarily affecting the left ventricle and interventricular septum while potentially causing obstruction within the left ventricular outflow tract (LVOT). The clinical manifestations of HCM are diverse, ranging from asymptomatic to severe heart failure (HF) and sudden cardiac death. Most patients present with obvious symptoms of left ventricular outflow tract obstruction (LVOTO). The diagnosis of HCM mainly depends on echocardiography and other imaging examinations. In recent years, myosin inhibitors have undergone clinical trials and gene therapy, which is expected to become a new treatment for HCM, has been studied. This article summarizes recent clinical updates on the epidemiology, pathogenesis, diagnostic methods, treatment principles, and complication prevention and treatment of HCM, to provide new ideas for follow-up research.

Valerenic acid attenuates pathological myocardial hypertrophy by promoting the utilization of multiple substrates in the mitochondrial energy metabolism

INTRODUCTION

Valerenic acid (VA) is a unique and biologically active component in Valeriana officinalis L., which has been reported to have a regulatory effect on the cardiovascular system. However, its therapeutic effects on pathological myocardial hypertrophy (PMH) and the underlying mechanisms are undefined.

OBJECTIVES

Our study aims to elucidate how VA improves PMH, and preliminarily discuss its mechanism.

METHODS

The efficacy of VA on PMH was confirmed by in vivo and in vitro experiments and the underlying mechanism was investigated by molecular dynamics (MD) simulations and specific siRNA interference.

RESULTS

VA enhanced cardiomyocyte fatty acid oxidation (FAO), inhibited hyper-activated glycolysis, and improved the unbalanced pyruvate-lactate axis. VA could significantly improve impaired mitochondrial function and reduce the triglyceride (TG) in the hypertrophic myocardium while reducing the lactate (LD) content. Molecular mechanistic studies showed that VA up-regulated the expression of peroxisome proliferator-activated receptor-α (PPARα) and downstream FAO-related genes including CD36, CPT1A, EHHADH, and MCAD. VA reduced the expression of ENO1 and PDK4, the key enzymes in glycolysis. Meanwhile, VA improved the pyruvate-lactate axis and promoted the aerobic oxidation of pyruvate by inhibiting LDAH and MCT4. MD simulations confirmed that VA can bind with the F273 site of PPARα, which proposes VA as a potential activator of the PPARα.

CONCLUSION

Our results demonstrated that VA might be a potent activator for the PPARα-mediated pathway. VA directly targets the PPARα and subsequently promotes energy metabolism to attenuate PMH, which can be applied as a potentially effective drug for the treatment of HF.

Efficacy and safety of cardiac myosin inhibitors for symptomatic hypertrophic cardiomyopathy: a meta-analysis of randomized controlled trials

Introduction

Hypertrophic cardiomyopathy (HCM) is a common genetic heart disorder. It is characterized by left ventricular hypertrophy and impaired cardiac function, with forms categorized into obstructive (oHCM) and nonobstructive (nHCM). Traditional treatments address symptoms but not the underlying disease mechanism, highlighting the need for novel therapies. Cardiac myosin inhibitors such as mavacamten and aficamten present potential new treatment options.

Methods

A meta-analysis of randomized controlled trials (RCTs) was conducted following PRISMA guidelines. Studies comparing cardiac myosin inhibitors with placebo were reviewed, and outcomes related to NYHA functional class, Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS), LVOT gradients, and left ventricular ejection fraction (LVEF) were analyzed.

Results

Six RCTs involving 826 participants demonstrated that mavacamten and aficamten significantly improved NYHA functional class and KCCQ-CSS scores. The incidence of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs) was similar between the treatment and control groups, indicating a comparable safety profile.

Conclusion

Cardiac myosin inhibitors are effective in improving cardiac function and reducing LVOT obstruction in HCM patients. They offer a promising alternative to current treatments, with a safety profile comparable to placebo. Further research is needed to confirm long-term benefits.

Advances in genetic diagnosis and therapy of hereditary heart disease: a bibliometric review from 2004 to 2024

Hereditary heart disease (HHD) is a series of cardiac disorders associated with monogenic or polygenic abnormalities and is one of the leading causes of sudden death, particularly in young adults. The updated European Cardiology guideline for cardiomyopathies provides the first comprehensive summary of genotyping, imaging, and therapy recommendations for inherited cardiomyopathies, but still lacks a comprehensive discussion of research advances and future trends in genetic diagnosis and therapy of HHD. Our research aims to fill this gap. Bibliometric analysis software (CiteSpace 6.3.R1, VOSviewer 1.6.18, and Scimago Graphica) was used to analyze the general information, trends, and emerging foci of HHD in the past 20 years, including author, country, institution, keyword, and so on. There were 5,757 publications were screened and aggregated in the database, including 1876 reviews and 3,881 articles. Hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), Brugada syndrome (BrS), myocardial amyloidosis, and Fabry disease (FD) were the main types of HHD that were explored in greater depth. Moreover, new diagnostic methods, clinical cohorts, and genetically targeted therapies for HHD patients are key research hotspots. The relationship between the pathogenicity of genes and prognosis will become increasingly important for therapy.

Mendelian Randomization Study on the Associations Between Genetically Predicted Cardiovascular Disease Subtypes and the Risk of Developing Cardiomyopathies

Cardiomyopathies are commonly believed to have genetic origins; however, the connection between cardiomyopathies and cardiovascular diseases remains uncertain. Thus, we employed a Mendelian randomization (MR) approach to investigate the potential causal effects of specific cardiovascular disease subtypes on dilated and hypertrophic cardiomyopathies, focusing primarily on a European population. Summary-level data for cardiomyopathies and other cardiovascular diseases were obtained from public genome-wide association studies. Random-effects inverse-variance weighting was used as the primary analysis, whereas sensitivity analyses, including weighted median, MR-Egger, and multivariable MR methods, were also conducted. A genetic predisposition to atrial fibrillation [odds ratio (OR): 1.33; 95% confidence interval (CI): 1.18-1.50; P < 0.001], heart failure (OR: 3.22; 95% CI: 1.92-5.41; P < 0.001), and hypertension (OR: 1.50; 95% CI: 1.25-1.81; P < 0.001) were causally linked to an increased risk of developing dilated cardiomyopathy. However, there was no direct causal connection between genetically predicted coronary heart disease, pulmonary embolism, or ischemic stroke and the risk of developing dilated cardiomyopathy. In contrast, no significant associations were found between genetically predicted CVD subtypes and the risk of developing hypertrophic cardiomyopathy. Genetically predicted heart failure is significantly associated with the risk of developing dilated cardiomyopathy, underscoring the importance of effective heart failure management for risk prevention. Moreover, individuals with hypertension and atrial fibrillation might have an increased predisposition to dilated cardiomyopathy, highlighting crucial implications for management.

Transcriptomic and genetic profiling in a spontaneous non-human primate model of hypertrophic cardiomyopathy and sudden cardiac death

Hypertrophic cardiomyopathy (HCM) afflicts humans, cats, pigs, and rhesus macaques. Disease sequelae include congestive heart failure, thromboembolism, and sudden cardiac death (SCD). Sarcomeric mutations explain some human and cat cases, however, the molecular basis in rhesus macaques remains unknown. RNA-Seq of the LV tissues of five HCM-affected and seven healthy control rhesus macaques was employed for differential transcriptomic analyses. DNA from 15 severely HCM-affected and 21 healthy geriatric rhesus macaques were selected for whole-genome sequencing. A genome-wide association study (GWAS) of disease status and SCD outcome was performed. 614 down- and 1,065 upregulated differentially expressed genes (DEGs) were identified between groups. The top DEG (MAFF) was overexpressed in affected animals (log2FoldChange = 4.71; PAdjusted-value = 1.14E-133). Channelopathy-associated enriched terms were identified in ~ 57% of downregulated DEGs providing transcriptomic evidence of hypertrophic and arrhythmic disease processes. For GWAS, no putative variant withstood segregation. Polygenic modeling analysis resulted in poor prediction power and burden testing could not explain HCM by an association of multiple variants in any gene. Neither single nor compound genetic variant(s), or identified polygenic profile, suggest complex genotype-phenotype interactions in rhesus macaques. Brought forth is an established dataset of robustly phenotyped rhesus macaques as an open-access resource for future cardiovascular disease genetic studies.

Identification and validation of differentially expressed disulfidptosis-related genes in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is one of the most common cardiovascular diseases with no effective treatment due to its complex pathogenesis. A novel cell death, disulfidptosis, has been extensively studied in the cancer field but rarely in cardiovascular diseases. This study revealed the potential relationship between disulfidptosis and hypertrophic cardiomyopathy and put forward a predictive model containing disulfidptosis-associated genes (DRGs) of GYS1, MYH10, PDMIL1, SLC3A2, CAPZB, showing excellent performance by SVM machine learning model. The results were further validated by western blot, RNA sequencing and immunohistochemistry in a TAC mice model. In addition, resveratrol was selected as a therapeutic drug targeting core genes using the CTD database. In summary, this study provides new perspectives for exploring disulfidptosis-related biomarkers and potential therapeutic targets for hypertrophic cardiomyopathy.

The transmission of mutation effects in a multiprotein machine: A comprehensive metadynamics study of the cardiac thin filament

The binding of Ca2+ ions within the troponin core of the cardiac thin filament (CTF) regulates normal contraction and relaxation. Mutations within the troponin complexes are known to alter normal functions and result in the eventual development of cardiomyopathy. However, despite the importance of the problem, detailed microscopic knowledge of the mechanism of pathogenic effect of point mutations and their effects on the conformational free energy surface of CTF remains elusive. Mutations are known to transmit their effects hundreds of angstroms along this protein complex and between different component proteins. To explore the impact of point mutations on the conformational free energy barrier between the closed and blocked state of CTF, and to understand the transmission of mutation, we have carried out metadynamics simulations for the wild-type (WT) and two mutants (cardiac troponin T Arg92Trp (R92W) and Arg92Leu (R92L)). Specifically, we have investigated the conformational modification of the tropomyosin (Tm) and the troponin (Tn) complex during the closed-to-blocked state transition for both the WT and two hypertrophic cardiomyopathy causing mutations. Our calculations demonstrated that mutations within the cardiac troponin T (cTnT) protein alter conformational properties of the Tm and the other proteins of the Tn complex as well as the Ca2+ binding affinity of the cTnC protein through the indirect mediation of cardiac troponin I (cTnI). Importantly, the data revealed a significant influence of the mutations on the conformational transition free energy barriers for both the Tm and cTnC proteins. Furthermore, we found both mutations independently alter the free energy barrier of transitions of cTnT. Such alteration in the free energy upon mutation of one protein in a complex, allosterically affects the others through structural and dynamical changes, leading to a pathogenic effect on the function of the thin filament.

Hypertrophic Cardiomyopathy with Special Focus on Mavacamten and Its Future in Cardiology

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of heart muscle disorders that affects millions, with an incidence from 1 in 500 to 1 in 200. Factors such as genetics, age, gender, comorbidities, and environmental factors may contribute to the course of this disease. Diagnosis of HCM has improved significantly in the past few decades from simple echocardiographic evaluations to a more complex, multimodal approach embracing advanced imaging, genetic, and biomarker studies. This review focuses on Mavacamten, a selective allosteric inhibitor of cardiac myosin, as a pharmacological treatment for HCM. Patients with HCM experience pathological actomyosin interactions, leading to impaired relaxation and increased energy expenditure. Mavacamten decreases available myosin heads, reducing actomyosin cross-bridges during systole and diastole. By reducing the number of bridges left ventricular outflow tract pressure is normalized and cardiac cavities are filled. This mechanism enhances patient performance and alleviates symptoms such as chest pain and dyspnea. The results suggest the potential for Mavacamten to transform the treatment of obstructive hypertrophic cardiomyopathy. Studies to date have shown significant improvement in exercise capacity, symptom relief, and a reduction in the need for invasive procedures such as septal myectomy. Further studies are needed to confirm the clinical results.

Efficacy and Safety of Aficamten in Symptomatic Nonobstructive Hypertrophic Cardiomyopathy: Results From the REDWOOD-HCM Trial, Cohort 4

BACKGROUND

This open-label phase 2 trial evaluated the safety and efficacy of aficamten in patients with nonobstructive hypertrophic cardiomyopathy (nHCM).

METHODS

Patients with symptomatic nHCM (left ventricular outflow tract obstruction gradient ≤ 30 mmHg, left ventricular ejection fraction [LVEF] ≥ 60%, N-terminal pro-B-type natriuretic peptide [NT-proBNP] > 300 pg/mL) received aficamten 5-15 mg once daily (doses adjusted according to echocardiographic LVEF) for 10 weeks.

RESULTS

We enrolled 41 patients (mean ± SD age 56 ± 16 years; 59% female). At Week 10, 22 (55%) patients experienced an improvement of ≥ 1 New York Heart Association class; 11 (29%) became asymptomatic. Clinically relevant improvements in Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores occurred in 22 (55%) patients. Symptom relief was paralleled by reductions in NT-proBNP levels (56%; P < 0.001) and high-sensitivity cardiac troponin I (22%; P < 0.005). Modest reductions in LVEF (mean ± SD) of -5.4% ± 10 to 64.6% ± 9.1 were observed. Three (8%) patients had asymptomatic reduction in LVEF < 50% (range: 41%-48%), all returning to normal after 2 weeks of washout. One patient with prior history of aborted sudden cardiac death experienced a fatal arrhythmia during the study.

CONCLUSIONS

Aficamten administration for symptomatic nHCM was generally safe and was associated with improvements in heart failure symptoms and cardiac biomarkers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04219826.

Treatment options for hypertrophic obstructive cardiomyopathy: a patient-centric review

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is defined by an increased left ventricular wall thickness not solely explainable by abnormal loading conditions. Estimated prevalence is 1:200-500 with roughly 60% of cases showing a familiar trait. Medical treatment and surgical interventions significantly altered prognosis in HCM. Recently, new therapies have been introduced in clinical practice and a patient-centric approach is key to HCM optimal management. This review aims to summarize the current HCM therapies focusing on the importance of personalized care and delineate therapeutic approaches under investigation.

AREAS COVERED

The review summarizes and critically evaluates the available data on currently available pharmacological and non-pharmacological therapies for HCM. The evidence in support of the use of beta-blockers, non-dihydropyridine calcium channel blockers, disopyramide, and cardiac myosin inhibitors is discussed. Furthermore, data and controversies on sudden death prevention, surgical and non-surgical septal reduction therapies are reported. Finally, future perspectives in HCM management such as new drugs and gene therapies are explored.

EXPERT OPINION

The authors stress the need for a personalized and tailored approach to managing patients with HCM, which is not only based on phenotypes and risk stratification, but also patients' preferences, needs, and beliefs.

Cardiomyopathy: pathogenesis and therapeutic interventions

Cardiomyopathy is a group of disease characterized by structural and functional damage to the myocardium. The etiologies of cardiomyopathies are diverse, spanning from genetic mutations impacting fundamental myocardial functions to systemic disorders that result in widespread cardiac damage. Many specific gene mutations cause primary cardiomyopathy. Environmental factors and metabolic disorders may also lead to the occurrence of cardiomyopathy. This review provides an in-depth analysis of the current understanding of the pathogenesis of various cardiomyopathies, highlighting the molecular and cellular mechanisms that contribute to their development and progression. The current therapeutic interventions for cardiomyopathies range from pharmacological interventions to mechanical support and heart transplantation. Gene therapy and cell therapy, propelled by ongoing advancements in overarching strategies and methodologies, has also emerged as a pivotal clinical intervention for a variety of diseases. The increasing number of causal gene of cardiomyopathies have been identified in recent studies. Therefore, gene therapy targeting causal genes holds promise in offering therapeutic advantages to individuals diagnosed with cardiomyopathies. Acting as a more precise approach to gene therapy, they are gradually emerging as a substitute for traditional gene therapy. This article reviews pathogenesis and therapeutic interventions for different cardiomyopathies.

Integrative analysis of transcriptome, DNA methylome, and chromatin accessibility reveals candidate therapeutic targets in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease and is characterized by primary left ventricular hypertrophy usually caused by mutations in sarcomere genes. The mechanism underlying cardiac remodeling in HCM remains incompletely understood. An investigation of HCM through integrative analysis at multi-omics levels will be helpful for treating HCM. DNA methylation and chromatin accessibility, as well as gene expression, were assessed by nucleosome occupancy and methylome sequencing (NOMe-seq) and RNA-seq, respectively, using the cardiac tissues of HCM patients. Compared with those of the controls, the transcriptome, DNA methylome, and chromatin accessibility of the HCM myocardium showed multifaceted differences. At the transcriptome level, HCM hearts returned to the fetal gene program through decreased sarcomeric and metabolic gene expression and increased extracellular matrix gene expression. In the DNA methylome, hypermethylated and hypomethylated differentially methylated regions were identified in HCM. At the chromatin accessibility level, HCM hearts showed changes in different genome elements. Several transcription factors, including SP1 and EGR1, exhibited a fetal-like pattern of binding motifs in nucleosome-depleted regions in HCM. In particular, the inhibition of SP1 or EGR1 in an HCM mouse model harboring sarcomere mutations markedly alleviated the HCM phenotype of the mutant mice and reversed fetal gene reprogramming. Overall, this study not only provides a high-precision multi-omics map of HCM heart tissue but also sheds light on the therapeutic strategy by intervening in the fetal gene reprogramming in HCM.

A Machine Learning Approach to Gene Expression in Hypertrophic Cardiomyopathy

BACKGROUND/OBJECTIVES

Hypertrophic cardiomyopathy (HCM) is a common heart disorder characterized by the thickening of the heart muscle, particularly in the left ventricle, which increases the risk of cardiac complications. This study aims to analyze the expression of apoptosis-regulating genes (CASP8, CASP9, CASP3, BAX, and BCL2) in blood samples from HCM patients, to better understand their potential as biomarkers for disease progression.

METHODS

Quantitative real-time PCR (qPCR) was used to evaluate gene expression in blood samples from 93 HCM patients. The correlation between apoptosis-regulating genes was conducted and clinical parameters were integrated for feature importance and clustering analysis.

RESULTS

Most patients exhibited significant downregulation of CASP8, CASP9, and CASP3. In contrast, BAX expression was elevated in 71 out of 93 patients, while BCL2 was increased in 55 out of 93 patients. Correlation analysis revealed weak negative correlations between the BAX/BCL2 ratio and CASP gene expression.

CONCLUSIONS

These findings suggest that reduced expression of apoptotic genes may indicate a protective cellular mechanism, which could serve as a biomarker for disease progression. Further studies are needed to investigate the potential for therapeutic modulation of these pathways to improve patient outcomes.

Left Bundle Branch Pacing for Bradycardia in Non-obstructive Hypertrophic Cardiomyopathy Patients: Feasibility, Safety, and Effect

PURPOSE

Left bundle branch pacing (LBBP) is as an innovative physiological pacing approach. The research on LBBP in non-obstructive hypertrophic cardiomyopathy (NOHCM) patients is scarce. This study aimed to assess the feasibility, safety, and effect of LBBP in bradycardia NOHCM patients with permanent pacemaker (PPM) implantation indication.

METHODS

Thirteen consecutive patients with NOHCM who received LBBP were retrospectively enrolled as a hypertrophic cardiomyopathy (HCM) group. Following 1:3 matching, 39 patients without HCM were randomly matched as a control group. Echocardiographic index and pacing parameters were collected.

RESULTS

The successful LBBP was achieved in 96.2% of all cases (50/52), and the success rate of the HCM group was 92.3% (12/13). In the HCM group, the paced QRS duration (from the pacing stimulus to QRS end) was 145.6±20.8 ms. The stimulus to left ventricular activation time (s-LVAT) was 87.4±15.2 ms. In the control group, the paced QRS duration was 139.4±17.2 ms, and the s-LVAT was 79.9±14.1 ms. During the implantation, R-wave sensing and the pacing threshold of the HCM group were significantly higher than the control group (20.2±10.5 vs 12.5±5.9 mV, P < 0.05; 0.8±0.3 vs 0.6±0.2V/0.4 ms, P < 0.05). In addition, the fluoroscopic duration and procedural duration were longer in the HCM group (14.8±8.3 vs 10.3±6.6min, P = 0.07; 131.8±50.5 vs 101.4±41.6 min, P < 0.05). The lead insertion depth was 15±2 mm in the HCM group, and no procedure-related complications occurred. During the 12-month follow-up, pacing parameters remained stable and were of no significance in the two groups. The cardiac function did not deteriorate, and the left ventricular outflow tract gradient (LVOTG) did not increase in the follow-up.

CONCLUSION

LBBP might be feasible and safe for NOHCM patients with conventional bradycardia pacing indication, and there is no deterioration in cardiac function and LVOTG of patients with NOHCM.

Clinical Characteristics and Outcomes in Patients With Apical and Nonapical Hypertrophic Cardiomyopathy

BACKGROUND

Apical hypertrophic cardiomyopathy (ApHCM) is a variant of hypertrophic cardiomyopathy, with distinct clinical characteristics and outcomes. We aimed to clarify the natural history of patients with ApHCM and identify the risk of end-stage heart failure incidence.

METHODS AND RESULTS

This retrospective study was conducted on patients with hypertrophic cardiomyopathy in China between January 2009 and February 2024. Patients were stratified into ApHCM and non-ApHCM groups. The primary outcome was a composite of major adverse cardiovascular events, including all-cause deaths, heart failure hospitalization, sudden cardiac death, and ventricular tachycardia. The secondary outcome was the incidence of end-stage heart failure, defined as left ventricular ejection fraction <50%. Kaplan-Meier and univariable and multivariable Cox proportional analyses were applied. Adjustment variables were included for important baseline characteristics, comorbidities, and medication use. Of 5653 patients enrolled with hypertrophic cardiomyopathy, 584 (10.3%) had ApHCM and 5069 (89.7%) had non-ApHCM. During the median follow-up period of 4.6 years (1.6-8.0 years), major adverse cardiovascular events occurred in 32.2% (n=1808), with a lower incidence in patients with ApHCM than non-ApHCM (20.4% versus 33.3%, P<0.001). Non-ApHCM was an independent predictor of major adverse cardiovascular events (hazard ratio [HR], 1.65 [95% CI, 1.36-1.99]; P<0.001). In the serial cohort, patients with ApHCM exhibited a lower incidence of end-stage heart failure than those with non-ApHCM (12.4% versus 2.7%, P<0.001). Non-ApHCM was associated with a higher risk of end-stage heart failure development (HR, 2.31 [95% CI, 1.28-4.15]; P<0.001). In subgroup and sensitivity analysis, the results were consistent for our main and secondary outcomes.

CONCLUSIONS

ApHCM is relatively common in hypertrophic cardiomyopathy and shows lower rates of all-cause mortality and heart failure hospitalizations than non-ApHCM.

Function and mechanism of lysine crotonylation in health and disease

Lysine crotonylation is a newly identified posttranslational modification that is different from the widely studied lysine acetylation in structure and function. In the last dozen years, great progress has been made in lysine crotonylation-related studies, and lysine crotonylation is involved in reproduction, development and disease. In this review, we highlight the similarities and differences between lysine crotonylation and lysine acetylation. We also summarize the methods and tools for the detection and prediction of lysine crotonylation. At the same time, we outline the recent advances in understanding the mechanisms of enzymatic and metabolic regulation of lysine crotonylation, as well as the regulating factors that selectively recognize this modification. Particularly, we discussed how dynamic changes in crotonylation status maintain physiological health and result in the development of disease. This review not only points out the new functions of lysine crotonylation but also provides new insights and exciting opportunities for managing various diseases.

Identification of ATRNL1 and WNT9A as novel key genes and drug candidates in hypertrophic cardiomyopathy: integrative bioinformatics and experimental validation

Background

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by left ventricular hypertrophy that can lead to heart failure, arrhythmias, and sudden cardiac death. Despite extensive research, the molecular mechanisms underlying HCM are not fully understood, and effective treatments remain limited. By leveraging bioinformatics and experimental validation, this study aims to identify key genes and pathways involved in HCM, uncover novel drug candidates, and provide new insights into its pathogenesis and potential therapeutic strategies.

Methods

Commonly upregulated and downregulated genes in hypertrophic cardiomyopathy (HCM) were identified using Gene Expression Omnibus (GEO) datasets, including three mRNA profiling datasets and one miRNA expression dataset. Enrichment analysis and hub-gene exploration were performed using interaction networks and consistent miRNA-mRNA matches. Potential drugs for HCM were screened. HCM cellular and animal models were established using isoproterenol. Key unstudied differentially expressed genes (DEGs) were validated. Animals were treated with novel potential drugs, and improvements in HCM were assessed via ultrasound metrics. Hematoxylin and eosin (H&E) staining was used to assess myocardial fibrosis. Immunohistochemistry was employed to detect DEGs in cellular experiments.

Result

We discovered 145 key upregulated and 149 downregulated DEGs associated with HCM development, among which there are eight core upregulated and seven core downregulated genes. There are 30 upregulated and six downregulated miRNAs. Between the six downregulated miRNAs and 1291 matched miRNAs (against eight core upregulated DEGs), there is one common miRNA, miR-1469. Using the CTD database, drugs that impact the expression/abundance/methylation/metabolic process of core DEGs (after the exclusion of toxic drugs) included acetaminophen, propylthiouracil, methapyrilene, triptolide, tretinoin, etc. In the HCM cell model, only ATRNL1 and WNT9A were significantly increased. In the HCM animal model, propylthiouracil, miR-1469, and triptolide demonstrated varying degrees of therapeutic effects on HCM. Propylthiouracil, but not miR-1469 or triptolide, significantly inhibited the expression of ATRNL1 in the HCM model, and all three drugs suppressed WNT9A expression.

Conclusion

We identified several novel genes in HCM development, among which ATRNL1 and WNT9A were validated by cell and animal models. A deficiency of hsa-miR-1469 may be a mechanism behind HCM development. Novel medications for HCM treatment include propylthiouracil and triptolide.

A Review of Pediatric Cardiomyopathy

Though pediatric cardiomyopathy is rare in children, there is significant associated morbidity and mortality. Etiology varies from inborn errors of metabolism to familial genetic mutations and myocyte injury. Major classes include dilated, hypertrophic, restrictive, and non-compaction. Diagnosis generally involves a combination of clinical history and echocardiography. The use of cross-sectional imaging is gaining popularity. Management varies between subtype and may involve a combination of medical and surgical interventions depending on clinical status.

Machine learning-driven diagnostic signature provides new insights in clinical management of hypertrophic cardiomyopathy

AIMS

In an era of evolving diagnostic possibilities, existing diagnostic systems are not fully sufficient to promptly recognize patients with early-stage hypertrophic cardiomyopathy (HCM) without symptomatic and instrumental features. Considering the sudden death of HCM, developing a novel diagnostic model to clarify the patients with early-stage HCM and the immunological characteristics can avoid misdiagnosis and attenuate disease progression.

METHODS AND RESULTS

Three hundred eighty-five samples from four independent cohorts were systematically retrieved. The weighted gene co-expression network analysis, differential expression analysis (|log2(foldchange)| > 0.5 and adjusted P < 0.05), and protein-protein interaction network were sequentially performed to identify HCM-related hub genes. With a machine learning algorithm, the least absolute shrinkage and selection operator regression algorithm, a stable diagnostic model was developed. The immune-cell infiltration and biological functions of HCM were also explored to characterize its underlying pathogenic mechanisms and the immune signature. Two key modules were screened based on weighted gene co-expression network analysis. Pathogenic mechanisms relevant to extracellular matrix and immune pathways have been discovered. Twenty-seven co-regulated genes were recognized as HCM-related hub genes. Based on the least absolute shrinkage and selection operator algorithm, a stable HCM diagnostic model was constructed, which was further validated in the remaining three cohorts (n = 385). Considering the tight association between HCM and immune-related functions, we assessed the infiltrating abundance of various immune cells and stromal cells based on the xCell algorithm, and certain immune cells were significantly different between high-risk and low-risk groups.

CONCLUSIONS

Our study revealed a number of hub genes and novel pathways to provide potential targets for the treatment of HCM. A stable model was developed, providing an efficient tool for the diagnosis of HCM.

Effect of Activated Charcoal on Mavacamten Pharmacokinetics in Healthy Participants

OBJECTIVE

To assess the effect of activated charcoal on the single-dose pharmacokinetics of mavacamten when administered 2 h or 6 h after mavacamten dosing.

METHODS

In this open-label, randomized, parallel-group study, healthy adults were randomized into three groups to receive mavacamten 15 mg alone or mavacamten 15 mg plus activated charcoal 50 g administered either 2 h or 6 h after mavacamten dosing. Pharmacokinetic parameters were derived from plasma concentration-time data using noncompartmental methods.

RESULTS

Of the 45 participants randomized, 37 completed the study. When activated charcoal was administered 2 h after mavacamten dosing, mavacamten absorption and exposure were reduced compared with when mavacamten was administered alone: the area under the concentration-time curve from 0 to 72 h (AUC0-72) and area under the concentration-time curve from time 0 extrapolated to infinity (AUCINF) were reduced by 14% and 34%, respectively. The maximum plasma concentration (Cmax) was also slightly lower when activated charcoal was administered 2 h after mavacamten dosing than with mavacamten alone. Pharmacokinetic profiles were similar for mavacamten alone and mavacamten plus activated charcoal administered 6 h after mavacamten dosing.

CONCLUSIONS

Activated charcoal was successful in reducing mavacamten absorption and exposure when administered as soon as possible after identification of a need for adsorption (2 h after mavacamten dosing). No change in exposure was observed when activated charcoal was administered 6 h after mavacamten dosing.

CLINICAL TRIAL REGISTRATION

NCT05320094.

Tail length and E525K dilated cardiomyopathy mutant alter human β-cardiac myosin super-relaxed state

Dilated cardiomyopathy (DCM) is a condition characterized by impaired cardiac function, due to myocardial hypo-contractility, and is associated with point mutations in β-cardiac myosin, the molecular motor that powers cardiac contraction. Myocardial function can be modulated through sequestration of myosin motors into an auto-inhibited "super-relaxed" state (SRX), which may be further stabilized by a structural state known as the "interacting heads motif" (IHM). Here, we sought to determine whether hypo-contractility of DCM myocardium results from reduced function of individual myosin molecules or from decreased myosin availability to interact with actin due to increased IHM/SRX stabilization. We used an established DCM myosin mutation, E525K, and characterized the biochemical and mechanical activity of wild-type and mutant human β-cardiac myosin constructs that differed in the length of their coiled-coil tail, which dictates their ability to form the IHM/SRX state. We found that short-tailed myosin constructs exhibited low IHM/SRX content, elevated actin-activated ATPase activity, and fast velocities in unloaded motility assays. Conversely, longer-tailed constructs exhibited higher IHM/SRX content and reduced actomyosin ATPase and velocity. Our modeling suggests that reduced velocities may be attributed to IHM/SRX-dependent sequestration of myosin heads. Interestingly, longer-tailed E525K mutants showed no apparent impact on velocity or actomyosin ATPase at low ionic strength but stabilized IHM/SRX state at higher ionic strength. Therefore, the hypo-contractility observed in DCM may be attributable to reduced myosin head availability caused by enhanced IHM/SRX stability in E525K mutants.

An overview of the treatments for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a very prevalent inherited disease with a wide global distribution and a prevalence rate of approximately 0.2% in the general population. Left ventricular hypertrophy (LVH) caused by sarcomere mutation is the primary reason of HCM. The histopathology feature is that cardiomyocyte hypertrophy, myocyte disorder and myocardial fibrosis lead to diminished diastolic function, left ventricular outflow tract obstruction (LVOTO) and arrhythmia, all of which result in serious cardiac complications. Previously, HCM was considered a malignant disease that was almost untreatable. With the improvement of medical standards and increasing awareness of HCM, it has become a highly treatable disease in contemporary times, with a significant decrease in mortality rates. However, there are still significant unmet requirements in the therapy of HCM. This paper draws on more than 100 references from the past four decades and summarizes current advances in the treatment of HCM. The article will review the pathogenesis and types, recent development in pharmacotherapy, invasive treatments and gene therapies, as well as dilemma and future development of HCM.

The China Hypertrophic Cardiomyopathy Project (CHCMP): The Rationale and Design of a Multicenter, Prospective, Registry Cohort Study

Hypertrophic cardiomyopathy (HCM) is associated with adverse outcomes, such as heart failure, arrhythmia, and mortality. Sudden cardiac death (SCD) is a common cause of death in HCM patients, and identification of patients at a high risk of SCD is crucial in clinical practice. The China Hypertrophic Cardiomyopathy Project is a hospital-based, multicenter, prospective, registry cohort study of HCM patients, covering a total of 3000 participants and with a 5-year follow-up plan. A large number of demographic characteristics and clinical data will be fully collected to identify prognostic factors in Chinese HCM patients. Furthermore, the main purpose of this study is to integrate demographic and clinical characteristics to establish new 5-year SCD risk predictive equations for Chinese HCM patients by the use of machine learning technologies. The project has crucial clinical significance for risk stratification and determination of HCM patients with high risk of adverse outcomes. CLINICAL TRIALS REGISTRATION: ChiCTR2300070909.

Genetic Mutations and Mitochondrial Redox Signaling as Modulating Factors in Hypertrophic Cardiomyopathy: A Scoping Review

Hypertrophic cardiomyopathy (HCM) is a heart condition characterized by cellular and metabolic dysfunction, with mitochondrial dysfunction playing a crucial role. Although the direct relationship between genetic mutations and mitochondrial dysfunction remains unclear, targeting mitochondrial dysfunction presents promising opportunities for treatment, as there are currently no effective treatments available for HCM. This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews guidelines. Searches were conducted in databases such as PubMed, Embase, and Scopus up to September 2023 using "MESH terms". Bibliographic references from pertinent articles were also included. Hypertrophic cardiomyopathy (HCM) is influenced by ionic homeostasis, cardiac tissue remodeling, metabolic balance, genetic mutations, reactive oxygen species regulation, and mitochondrial dysfunction. The latter is a common factor regardless of the cause and is linked to intracellular calcium handling, energetic and oxidative stress, and HCM-induced hypertrophy. Hypertrophic cardiomyopathy treatments focus on symptom management and complication prevention. Targeted therapeutic approaches, such as improving mitochondrial bioenergetics, are being explored. This includes coenzyme Q and elamipretide therapies and metabolic strategies like therapeutic ketosis. Understanding the biomolecular, genetic, and mitochondrial mechanisms underlying HCM is crucial for developing new therapeutic modalities.

Unveiling Immune Infiltration Characterizing Genes in Hypertrophic Cardiomyopathy Through Transcriptomics and Bioinformatics

Background

Hypertrophic cardiomyopathy (HCM) is a dominantly inherited disease associated with sudden immune cell associations that remain unclear. The aim of this study was to comprehensively screen candidate markers associated with HCM and immune cells and explore potential pathogenic pathways.

Methods

First, download the GSE32453 dataset to identify differentially expressed genes (DEGs) and perform Gene Ontology and pathway enrichment analysis using DAVID and GSEA. Next, construct protein-protein interaction (PPI) networks using String and Cytoscape to identify hub genes. Afterward, use CIBERSORT to determine the proportion of immune cells attributed to key genes in HCM and conduct ROC analysis based on the external dataset GSE36961 to evaluate their diagnostic value. Finally, validate the expression of key genes in the hypertrophic cardiomyocyte model through qRT-PCR using data from the HPA database.

Results

Comprehensive analysis revealed that there were 254 upregulated genes and 181 downregulated genes in HCM. The enrichment study underscored pathways of inflammatory signaling, including MAPK and PI3K-Akt pathways. Pathways abundant in genes associated with HCM encompassed myocardial contraction and NADH dehydrogenase activity. Additionally, the analysis of immune infiltration revealed a notable increase in macrophages, NK cells, and monocytes in the HCM group, showing statistically significant variances in CD4 memory resting T cell infiltration when compared to the healthy control group. Within the validation dataset GSE36961, the Area Under the Curve (AUC) scores for eight crucial genes (FOS, CD86, CD68, BDNF, PIK3R1, PLEK, RAC2, CCL2) each exceeded 0.8. The HPA database revealed the positioning traits and paths of these eight crucial genes in smooth muscle cells, myocardial cells, and fibroblasts. The outcomes of the qRT-PCR were aligned with the sequencing findings.

Conclusion

Bioinformatics analysis unveiled pivotal genes, pathways, and immune involvement, illuminating the molecular underpinnings of HCM. These findings suggest promising therapeutic targets for clinical applications.

Clinical characteristics and prognosis of patients with hypertrophic cardiomyopathy and heart failure with preserved ejection fraction

BACKGROUND

Whether heart failure with preserved ejection fraction (HFpEF) is associated with an increased risk of developing systolic dysfunction and a poor prognosis in hypertrophic cardiomyopathy (HCM) patients is unknown.

OBJECTIVE

We aimed to assess risk factors for the development of end-stage (ES) heart failure (HF) (ejection fraction < 50%) and compare the prognosis of different HF phenotypes.

METHODS

This retrospective study was conducted on patients with HCM in China between January 2009 and February 2023. Patients were stratified into three different groups: HCM-non-HF, HCM-HFpEF and HCM-heart failure with reduced ejection fraction (HCM-HFrEF). The primary outcome was a composite of major adverse cardiac events (MACEs), including all-cause deaths, HF hospitalization, sudden cardiac death and ventricular tachycardia.

RESULTS

Of 3,620 HCM patients enrolled, 1,553 (42.9%) had non-HF, 1,666 (46.0%) had HFpEF, and 579 patients (11.1%) had HFrEF at baseline. During the median follow-up period of 4.0 years (IQR 1.4-9.4 years), patients with HCM-HFpEF exhibited a higher incidence of ES-HF than those with HCM-non-HF (12.4% vs. 2.7%, P < 0.001). HFpEF was an independent risk factor for ES-HF development (HR 3.84, 2.54-5.80, P < 0.001). MACEs occurred in 26.9% with a higher incidence in HCM-HFpEF than HCM-non-HF (36.6% vs 12.2%, P < 0.001). HFpEF was an independent predictor of MACEs (HR 2.13, 1.75-2.59, P < 0.001).

CONCLUSIONS

HFpEF is common in HCM. Compared to non-HF, it increases the risk of LVEF decline and poor prognosis. It may aid in risk stratification and need close echocardiography follow-up.

The Revolution of Cardiac Myosin Inhibitors in Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy worldwide and causes significant morbidity and mortality. For decades, medical treatment options have been limited and untargeted, with frequent need for invasive interventions not readily accessible to many HCM patients. More recently, our understanding of the genetic basis and pathophysiologic mechanism of HCM has grown significantly, leading to the discovery of a new class of medications, cardiac myosin inhibitors (CMIs), that shift myosin into the super-relaxed state to counteract the hypercontractility in HCM. Subsequent clinical trials have proven the mechanism and efficacy of CMIs in humans with obstructive HCM, and additional trials are under way in patients with nonobstructive HCM. With favourable results in the completed clinical trials and ongoing research on the horizon, CMIs represent a bright new era in the targeted management of HCM. This review is focused on the discovery of CMIs, provides a summary of the results of clinical trials to date, provides clinicians with a roadmap for implementing CMIs into practice, and identifies gaps in our current understanding as well as areas of ongoing investigation.

Unravelling the role of cathepsins in cardiovascular diseases

Lysosomal cathepsins as a regulatory medium have been assessed as potential therapeutic targets for the treatment of various cardiac diseases such as abdominal aortic aneurysm, hypertension, cardiomyopathy, coronary heart disease, atherosclerosis, etc. They are ubiquitous lysosomal proteases with papain-like folded protein structures that are involved in a variety of physiological processes, such as the digestion of proteins, activation of pro-inflammatory molecules, degradation of extracellular matrix components, and maturation of peptide hormones. Cathepsins are classified into three major groups: cysteine cathepsins, aspartic cathepsins, and serine-threonine cathepsins. Each of these groups is further divided into subgroups based on their substrate specificity, structural characteristics, and biochemical properties. Several studies suggest that cathepsins control the degradation of ECM components such as collagen and elastin fibres. These enzymes are highly expressed in macrophages and inflammatory cells, and their upregulation has been demonstrated to be critical in the progression of atherosclerotic lesions. Additionally, increased cathepsin activity has been linked to increased vascular inflammation and oxidative stress, both of which are associated with CVDs. Specifically, the inhibition of cathepsins may reduce the release of pro-apoptotic mediators such as caspase-3 and PARP-1, which are thought to contribute to plaque instability. The potential of cathepsins as biomarkers and therapeutic targets has also been supported by the identification of potential cathepsin inhibitors, which could be used to modulate the activities of cathepsins in a range of diseases. This review shall familiarise the readers with the role of cysteinyl cathepsins and their inhibitors in the pathogenesis of cardiovascular diseases.

Evaluating the efficacy and safety of mavacamten in hypertrophic cardiomyopathy: A systematic review and meta-analysis focusing on qualitative assessment, biomarkers, and cardiac imaging

BACKGROUND

Hypertrophic Cardiomyopathy (HCM) is a complex cardiac condition characterized by hypercontractility of cardiac muscle leading to a dynamic obstruction of left ventricular outlet tract (LVOT). Mavacamten, a first-in-class cardiac myosin inhibitor, is increasingly being studied in randomized controlled trials. In this meta-analysis, we aimed to analyse the efficacy and safety profile of Mavacamten compared to placebo in patients of HCM.

METHOD

We carried out a comprehensive search in PubMed, Cochrane, and clinicaltrials.gov to analyze the efficacy and safety of mavacamten compared to placebo from 2010 to 2023. To calculate pooled odds ratio (OR) or risk ratio (RR) at 95% confidence interval (CI), the Mantel-Haenszel formula with random effect was used and Generic Inverse Variance method assessed pooled mean difference value at a 95% CI. RevMan was used for analysis. P<0.05 was considered significant.

RESULTS

We analyzed five phase 3 RCTs including 609 patients to compare mavacamten with a placebo. New York Heart Association (NYHA) grade improvement and KCCQ score showed the odds ratio as 4.94 and 7.93 with p<0.00001 at random effect, respectively. Cardiac imaging which included LAVI, LVOT at rest, LVOT post valsalva, LVOT post-exercise, and reduction in LVEF showed the pooled mean differences for change as -5.29, -49.72, -57.45, -36.11, and -3.00 respectively. Changes in LVEDV and LVMI were not statistically significant. The pooled mean difference for change in NT-proBNP and Cardiac troponin-I showed 0.20 and 0.57 with p<0.00001. The efficacy was evaluated in 1) A composite score, which was defined as either 1·5 mL/kg per min or greater increase in peak oxygen consumption (pVO2) and at least one NYHA class reduction, or a 3·0 mL/kg per min or greater pVO2 increase without NYHA class worsening and 2) changes in pVO2, which was not statistically significant. Similarly, any treatment-associated emergent adverse effects (TEAE), treatment-associated serious adverse effects (TSAE), and cardiac-related adverse effects were not statistically significant.

CONCLUSION

Mavacamten influences diverse facets of HCM comprehensively. Notably, our study delved into the drug's impact on the heart's structural and functional aspects, providing insights that complement prior findings. Further large-scale trials are needed to evaluate the safety profile of Mavacamten.

Transapical intramyocardial septal microwave ablation in treatment of hypertrophic obstructive cardiomyopathy: 12-month outcomes of a swine model

BACKGROUND

To date, the extended Morrow procedure is considered the gold standard treatment for patients with obstructive hypertrophic cardiomyopathy who experience severe symptoms and are unresponsive to medication treatment. We therefore aimed to perform transapical intramyocardial septal microwave ablation to reduce the thickness of the interventricular septum myocardium in a minimally invasive method.

METHODS

Fourteen swine were divided to form either a microwave ablation group (n = 7) or a sham group (n = 7). In the microwave ablation group, a transapical microwave antenna was inserted into the septum to ablate each myocardial segment at 40 W for 1 min, while in the sham group, the same operation was performed but without power output. We used echocardiography, electrocardiogram, during the operation. And added computerized tomography, cardiac nuclear magnetic resonance during follow-up.

RESULTS

Segment hypokinesis was observed in all swine immediately following ablation. Compared with the sham group, the thickness of ablated segments in the ablation group decreased significantly 1 month post-operation (ablation group, 5.53 ± 1.00 mm vs. 8.03 ± 1.15 mm, respectively, P < 0.01; sham group, 8.40 ± 0.94 mm vs. 8.21 ± 1.09 mm, respectively, P = 0.081), and the outcome was still observed 1 year post-operation (ablation group, 3.36 ± 0.85 mm vs. 8.03 ± 1.15 mm, respectively, P < 0.01). No perforation of the septum was observed during the procedure or follow-up, and no heart failure or sudden cardiac death occurred during postoperative feeding.

CONCLUSIONS

Transapical intramyocardial septal microwave ablation can effectively and safely produce a large region of necrosis. This technique can potentially mimic surgical myectomy while avoiding cardiopulmonary bypass and median sternotomy in high-risk hypertrophic obstructive cardiomyopathy patients.

Comparing long-term outcomes of septal myectomy and mitral valve replacement in hypertrophic cardiomyopathy patients: A retrospective cohort study in Iran

Background

Hypertrophic cardiomyopathy (HCM) affects millions of individuals worldwide. In severe cases, it can cause life-threatening conditions such as left ventricular outflow tract (LVOT) obstruction, mitral regurgitation (MR), and sudden cardiac death, making surgical treatment necessary. This study aimed to report the long-term outcomes of HCM patients undergoing septal myectomy or mitral valve replacement (MVR) and compare the results between different types of surgeries.

Methods

This was a retrospective cohort study on HCM patients who underwent surgical treatment in an Iranian referral center between 2005 and 2021. Patients were divided into three groups according to the type of surgery received: septal myectomy, MVR, or a combination of both surgeries. Patient characteristics, surgical and echocardiographic features, and in-hospital and long-term outcomes were reported and compared between the three groups.

Results

A total of 102 patients with an average age of 53.3 ± 16.9 were included. Twenty-six patients had septal myectomy, 23 had MVR, and 53 had combined septal myectomy and MVR surgery. All surgeries were associated with a significant reduction in interventricular septum thickness and LVOT gradients. After a median of 6.8-year follow-up time, patients with an isolated septal myectomy had significantly lower mortality and major adverse cardiac and cerebrovascular events rates than the other groups.

Conclusion

Isolated septal myectomy showed better long-term survival rates and can correct HCM-related MR, while MVR should be preserved only for intrinsic valve defects. More extensive studies are needed to confirm these findings and achieve a comprehensive guideline on surgical treatment of HCM.

The Role of Stem Cells in the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death and include several vascular and cardiac disorders, such as atherosclerosis, coronary artery disease, cardiomyopathies, and heart failure. Multiple treatment strategies exist for CVDs, but there is a need for regenerative treatment of damaged heart. Stem cells are a broad variety of cells with a great differentiation potential that have regenerative and immunomodulatory properties. Multiple studies have evaluated the efficacy of stem cells in CVDs, such as mesenchymal stem cells and induced pluripotent stem cell-derived cardiomyocytes. These studies have demonstrated that stem cells can improve the left ventricle ejection fraction, reduce fibrosis, and decrease infarct size. Other studies have investigated potential methods to improve the survival, engraftment, and functionality of stem cells in the treatment of CVDs. The aim of the present review is to summarize the current evidence on the role of stem cells in the treatment of CVDs, and how to improve their efficacy.

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Deficiency of Transcription Factor Sp1 Contributes to Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disorder. However, the pathogenesis of HCM, especially its nongenetic mechanisms, remains largely unclear. Transcription factors are known to be involved in various biological processes including cell growth. We hypothesized that SP1 (specificity protein 1), the first purified TF in mammals, plays a role in the cardiomyocyte growth and cardiac hypertrophy of HCM.

METHODS

Cardiac-specific conditional knockout of Sp1 mice were constructed to investigate the role of SP1 in the heart. The echocardiography, histochemical experiment, and transmission electron microscope were performed to analyze the cardiac phenotypes of cardiac-specific conditional knockout of Sp1 mice. RNA sequencing, chromatin immunoprecipitation sequencing, and adeno-associated virus experiments in vivo were performed to explore the downstream molecules of SP1. To examine the therapeutic effect of SP1 on HCM, an SP1 overexpression vector was constructed and injected into the mutant allele of Myh6 R404Q/+ (Myh6 c. 1211C>T) HCM mice. The human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with HCM were used to detect the potential therapeutic effects of SP1 in human HCM.

RESULTS

The cardiac-specific conditional knockout of Sp1 mice developed a typical HCM phenotype, displaying overt myocardial hypertrophy, interstitial fibrosis, and disordered myofilament. In addition, Sp1 knockdown dramatically increased the cell area of hiPSC-CMs and caused intracellular myofibrillar disorganization, which was similar to the hypertrophic cardiomyocytes of HCM. Mechanistically, Tuft1 was identified as the key target gene of SP1. The hypertrophic phenotypes induced by Sp1 knockdown in both hiPSC-CMs and mice could be rescued by TUFT1 (tuftelin 1) overexpression. Furthermore, SP1 overexpression suppressed the development of HCM in the mutant allele of Myh6 R404Q/+ mice and also reversed the hypertrophic phenotype of HCM hiPSC-CMs.

CONCLUSIONS

Our study demonstrates that SP1 deficiency leads to HCM. SP1 overexpression exhibits significant therapeutic effects on both HCM mice and HCM hiPSC-CMs, suggesting that SP1 could be a potential intervention target for HCM.

Treatment Strategies for Hypertrophic Cardiomyopathy: Alcohol Septal Ablation and Procedural Step-by-Step Technique

Alcohol septal ablation (ASA) is a well-established procedure for septal reduction therapy in patients with obstructive hypertrophic cardiomyopathy, significant at rest or provocable outflow tract gradients, and medically refractory symptoms. This percutaneous approach to relief of obstruction and eventual cardiac remodeling involves the infusion of a small quantity of ethanol into an appropriately targeted septal artery that is feeding the basal septum to create an iatrogenic and controlled focal infarction. Early akinesia is followed by subsequent thinning and remodeling, which widens the outflow tract, reducing or eliminating the obstruction. Historically, the use of ASA was reserved primarily for high-risk surgical candidates; however, more contemporary data suggest similar outcomes in the short-term and long-term safety of the procedure and overall effectiveness in relieving obstructive symptoms when it is performed in broader populations at experienced centers. Therefore, the current guidelines published in 2020 support ASA as a class 1 indication, similar to its open-heart surgical counterpart, surgical myectomy, when no concomitant significant coronary or valve surgical indication exists. This article summarizes contemporary management of patients with hypertrophic cardiomyopathy who were selected for ASA and details procedural methods and outcomes.

miRNAs in Heart Development and Disease

Cardiovascular diseases (CVD) are a group of disorders that affect the heart and blood vessels. They include conditions such as myocardial infarction, coronary artery disease, heart failure, arrhythmia, and congenital heart defects. CVDs are the leading cause of death worldwide. Therefore, new medical interventions that aim to prevent, treat, or manage CVDs are of prime importance. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional level and play important roles in various biological processes, including cardiac development, function, and disease. Moreover, miRNAs can also act as biomarkers and therapeutic targets. In order to identify and characterize miRNAs and their target genes, scientists take advantage of computational tools such as bioinformatic algorithms, which can also assist in analyzing miRNA expression profiles, functions, and interactions in different cardiac conditions. Indeed, the combination of miRNA research and bioinformatic algorithms has opened new avenues for understanding and treating CVDs. In this review, we summarize the current knowledge on the roles of miRNAs in cardiac development and CVDs, discuss the challenges and opportunities, and provide some examples of recent bioinformatics for miRNA research in cardiovascular biology and medicine.

Ultrasound study of right ventricular myocardial perfusion and functional changes in hypertrophic cardiomyopathy

BACKGROUND

To evaluate the changes of right ventricular (RV) myocardial perfusion and function in patients with hypertrophic cardiomyopathy (HCM) by myocardial contrast echocardiography (MCE) and speckle tracking (2D-STE), and to explore the relationship between RV myocardial perfusion and strain.

METHODS

Conventional ultrasound, MCE and 2D-STE were performed on 29 HCM patients and 21 healthy subjects to analyze RV myocardial perfusion, RV global strain, RV free wall strain, and strain of each segment. The correlation between RV myocardial perfusion and strain was further analyzed in HCM patients.

RESULTS

MCE results showed that the regional myocardial perfusion of the RV in HCM patients was decreased. Compared with the normal control group, the mean slope (β) in the middle and apical segments of the RV free wall, and the peak intensity (A), β, myocardial blood flow (MBF) of the ventricular septum decreased in HCM patients (P < 0.05). RV function was impaired in HCM patients. The RV global strain (RV GLS), and the strain of RV free wall and each segment were lower than those in the normal control group (P < 0.05). Correlation analysis showed that there was a certain correlation between RV myocardial perfusion and strain, such as the β of the whole RV in HCM group had a positive correlation with the strain of the middle segment of the interventricular septum (r = 0.550, P = 0.002).

CONCLUSIONS

The regional myocardial perfusion and strain of the RV in HCM patients are reduced, and there is a positive correlation between them, suggesting that the reduction of myocardial strain may be related to the impairment of myocardial microcirculation.

Tail Length and E525K Dilated Cardiomyopathy Mutant Alter Human β-Cardiac Myosin Super-Relaxed State

Dilated cardiomyopathy (DCM) is characterized by impaired cardiac function due to myocardial hypo-contractility and is associated with point mutations in β-cardiac myosin, the molecular motor that powers cardiac contraction. Myocardial function can be modulated through sequestration of myosin motors into an auto-inhibited "super relaxed" state (SRX), which is further stabilized by a structural state known as the "Interacting Heads Motif" (IHM). Therefore, hypo-contractility of DCM myocardium may result from: 1) reduced function of individual myosin, and/or; 2) decreased myosin availability due to increased IHM/SRX stabilization. To define the molecular impact of an established DCM myosin mutation, E525K, we characterized the biochemical and mechanical activity of wild-type (WT) and E525K human β-cardiac myosin constructs that differed in the length of their coiled-coil tail, which dictates their ability to form the IHM/SRX state. Single-headed (S1) and a short-tailed, double-headed (2HEP) myosin constructs exhibited low (~10%) IHM/SRX content, actin-activated ATPase activity of ~5s-1 and fast velocities in unloaded motility assays (~2000nm/s). Double-headed, longer-tailed (15HEP, 25HEP) constructs exhibited higher IHM/SRX content (~90%), and reduced actomyosin ATPase (<1s-1) and velocity (~800nm/s). A simple analytical model suggests that reduced velocities may be attributed to IHM/SRXdependent sequestration of myosin heads. Interestingly, the E525K 15HEP and 25HEP mutants showed no apparent impact on velocity or actomyosin ATPase at low ionic strength. However, at higher ionic strength, the E525K mutation stabilized the IHM/SRX state. Therefore, the E525K-associated DCM human cardiac hypo-contractility may be attributable to reduced myosin head availability caused by enhanced IHM/SRX stability.

Effects of Omeprazole and Verapamil on the Pharmacokinetics, Safety, and Tolerability of Mavacamten: Two Drug-Drug Interaction Studies in Healthy Participants

Two open-label, Phase 1 studies assessed the effects of omeprazole (a weak to moderate cytochrome P450 [CYP] 2C19 inhibitor) and verapamil (a moderate CYP3A4 inhibitor) on the pharmacokinetics, safety, and tolerability of mavacamten. In the omeprazole study, healthy participants received mavacamten 15 mg alone or with a 31-day course of omeprazole 20 mg once daily. In the verapamil study, healthy participants received mavacamten 25 mg alone or with a 28-day course of verapamil 240 mg once daily. In the omeprazole study, 27 of 29 randomized participants completed the study. Nine participants receiving mavacamten alone were normal metabolizers (NMs) of CYP2C19 substrates, and 6 were rapid metabolizers; 8 NMs and 6 rapid metabolizers received mavacamten + omeprazole. In both studies, mavacamten showed no safety signals and was generally well tolerated. Overall mavacamten exposure (area under the plasma concentration-time curve) increased by approximately 50% with omeprazole coadministration; maximum observed concentration (Cmax ), time to Cmax , and elimination half-life were not affected appreciably. In the verapamil study, 25 of 26 randomized participants received the study drug(s) and were included in the pharmacokinetic analyses; 24 completed the study. In the pharmacokinetic population, 12 participants received mavacamten alone (11 NMs, 1 poor metabolizer) and 13 received mavacamten + verapamil (7 NMs, 4 intermediate metabolizers, 2 poor metabolizers). Following verapamil coadministration in NMs and intermediate metabolizers, mavacamten area under the plasma concentration-time curve was minimally increased (by less than 20%), and Cmax was modestly increased (by 52%). These results suggest that mavacamten can be coadministered with weak CYP2C19 and moderate CYP3A4 inhibitors.

Low T3 syndrome predicts more adverse events in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a common cardiac genetic disorder that clinically manifests with sudden death and progressive heart failure. Moreover, thyroid dysfunction is associated with increased cardiovascular morbidity and mortality risks. Therefore, this study aimed to clarify whether thyroid hormones could serve as an independent predictor of adverse events in patients with HCM.

METHODS

The cohort consisted of 782 patients with HCM who had thyroid hormones baseline data and were admitted to the Affiliated Hospital of Jiaxing University. Patients were divided into two groups according to serum levels of free triiodothyronine (fT3): the normal fT3 and low triiodothyronine (T3) syndrome groups. Low T3 syndrome was defined as fT3 < 2.43 pmol/L with a normal thyroid-stimulating hormone (TSH) level. Patients whose TSH levels were abnormally high or abnormally low were excluded from this study. The primary endpoint was the occurrence of sudden cardiac death (SCD) events, and the secondary endpoint was a composite of worsening heart failure (WHF) events, including heart failure death, cardiac decompensation, hospitalization for heart failure, and HCM-related stroke. The Kaplan-Meier and Cox regression were performed for the survival analysis.

RESULTS

After a median follow-up of 52 months, 75 SCD events and 134 WHF events were recorded. The Kaplan-Meier survival curves showed that the cumulative incidence of SCD events and WHF events were significantly higher in patients with low T3 syndrome (log-rank p = .02 and log-rank p = .001, respectively). Furthermore, multivariate Cox regression analysis demonstrated that low T3 syndrome is a strong predictor of SCD events and WHF events (adjusted hazard ratio [HR: 1.53, 95% confidence interval [CI]: 1.13-2.24, p < .01; HR: 3.87, 95% CI: 2.91-4.98, p < .001, respectively).

CONCLUSIONS

Low T3 syndrome is highly prevalent among patients with HCM and was independently associated with an increased risk of SCD events and WHF events. The routine assessment of serum fT3 levels may provide risk stratification in this population.

Mitochondrial quality control in health and cardiovascular diseases

Cardiovascular diseases (CVDs) are one of the primary causes of mortality worldwide. An optimal mitochondrial function is central to supplying tissues with high energy demand, such as the cardiovascular system. In addition to producing ATP as a power source, mitochondria are also heavily involved in adaptation to environmental stress and fine-tuning tissue functions. Mitochondrial quality control (MQC) through fission, fusion, mitophagy, and biogenesis ensures the clearance of dysfunctional mitochondria and preserves mitochondrial homeostasis in cardiovascular tissues. Furthermore, mitochondria generate reactive oxygen species (ROS), which trigger the production of pro-inflammatory cytokines and regulate cell survival. Mitochondrial dysfunction has been implicated in multiple CVDs, including ischemia-reperfusion (I/R), atherosclerosis, heart failure, cardiac hypertrophy, hypertension, diabetic and genetic cardiomyopathies, and Kawasaki Disease (KD). Thus, MQC is pivotal in promoting cardiovascular health. Here, we outline the mechanisms of MQC and discuss the current literature on mitochondrial adaptation in CVDs.

The Role of Personalized Medicine in Companion Animal Cardiology

Cardiomyopathies remain one of the most common inherited cardiac diseases in both human and veterinary patients. To date, well over 100 mutated genes are known to cause cardiomyopathies in humans with only a handful known in cats and dogs. This review highlights the need and use of personalized one-health approaches to cardiovascular case management and advancement in pharmacogenetic-based therapy in veterinary medicine. Personalized medicine holds promise in understanding the molecular basis of disease and ultimately will unlock the next generation of targeted novel pharmaceuticals and aid in the reversal of detrimental effects at a molecular level.