-
Cardiovascular Diagnosis and Therapy Apr 2024Sarcomeric hypertrophic cardiomyopathy (HCM) must be differentiated from phenotypically similar conditions because clinical management and prognosis may greatly differ....
BACKGROUND
Sarcomeric hypertrophic cardiomyopathy (HCM) must be differentiated from phenotypically similar conditions because clinical management and prognosis may greatly differ. Patients with unexplained left ventricular hypertrophy require an early, confirmed genetic diagnosis through diagnostic or predictive genetic testing. We tested the feasibility and practicality of the application of a 17-gene next-generation sequencing (NGS) panel to detect the most common genetic causes of HCM and HCM phenocopies, including treatable phenocopies, and report detection rates. Identification of transthyretin cardiac amyloidosis (ATTR-CA) and Fabry disease (FD) is essential because of the availability of disease-specific therapy. Early initiation of these treatments may lead to better clinical outcomes.
METHODS
In this international, multicenter, cross-sectional pilot study, peripheral dried blood spot samples from patients of cardiology clinics with an unexplained increased left ventricular wall thickness (LVWT) of ≥13 mm in one or more left ventricular myocardial segments (measured by imaging methods) were analyzed at a central laboratory. NGS included the detection of known splice regions and flanking regions of 17 genes using the Illumina NextSeq 500 and NovaSeq 6000 sequencing systems.
RESULTS
Samples for NGS screening were collected between May 2019 and October 2020 at cardiology clinics in Colombia, Brazil, Mexico, Turkey, Israel, and Saudi Arabia. Out of 535 samples, 128 (23.9%) samples tested positive for pathogenic/likely pathogenic genetic variants associated with HCM or HCM phenocopies with double pathogenic/likely pathogenic variants detected in four samples. Among the 132 (24.7%) detected variants, 115 (21.5%) variants were associated with HCM and 17 (3.2%) variants with HCM phenocopies. Variants in (n=60, 11.2%) and (n=41, 7.7%) were the most common HCM variants. The HCM phenocopy variants included variants in the (n=7, 1.3%) and (n=2, 0.4%) genes. The mean (standard deviation) ages of patients with HCM or HCM phenocopy variants, including and variants, were 42.8 (17.9), 54.6 (17.0), and 69.0 (1.4) years, respectively.
CONCLUSIONS
The overall diagnostic yield of 24.7% indicates that the screening strategy effectively identified the most common forms of HCM and HCM phenocopies among geographically dispersed patients. The results underscore the importance of including ATTR-CA ( variants) and FD ( variants), which are treatable disorders, in the differential diagnosis of patients with increased LVWT of unknown etiology.
PubMed: 38716318
DOI: 10.21037/cdt-23-191 -
Veterinary and Animal Science Jun 2024This study compared the effect of four levels of K Humate S100R (potassium humate) supplementation on the quality, shelf-life, and nutritional properties of beef. Angus...
This study compared the effect of four levels of K Humate S100R (potassium humate) supplementation on the quality, shelf-life, and nutritional properties of beef. Angus steers ( = 40) were individually housed and fed either 0, 35, 70, or 140 g K Humate S100R/animal/day for 100 days, following a 30 day adjustment period. The steers were slaughtered at the completion of the feeding study. The left m. (LL) was collected at 24 h and aged for either 2 or 6 weeks before analysis. K Humate S100R supplementation did not affect beef drip loss, cooking loss, shear force, sarcomere length, ultimate pH, intramuscular fat content, or total volatile basic nitrogen concentrations ( > 0.05). Steers supplemented with 70 g/day K Humate S100R produced beef with higher * values on Days 1 and 3 of retail display ( < 0.05). Beef mineral composition was unchanged by K Humate S100R supplementation ( > 0.05), but there were minor changes to the fatty acid profile. Specifically, the ratio of omega-6 to omega-3 ( < 0.05) and C20:2n-6 concentrations ( < 0.05) increased with supplementation level. Together, these results demonstrate no detrimental effects on beef quality and shelf-life as a result of K Humate S100R supplementation.
PubMed: 38706515
DOI: 10.1016/j.vas.2024.100355 -
Clinics (Sao Paulo, Brazil) 2024The purpose of this study is to develop an animal model of Chronic Intermittent Hypoxia (CIH) and investigate the role of the TRPC5 channel in cardiac damage in OSAHS...
OBJECTIVE
The purpose of this study is to develop an animal model of Chronic Intermittent Hypoxia (CIH) and investigate the role of the TRPC5 channel in cardiac damage in OSAHS rats.
METHODS
Twelve male Sprague Dawley rats were randomly divided into the CIH group and the Normoxic Control (NC) group. Changes in structure, function, and pathology of heart tissue were observed through echocardiography, transmission electron microscopy, HE-staining, and TUNEL staining.
RESULTS
The Interventricular Septum thickness at diastole (IVSd) and End-Diastolic Volume (EDV) of rats in the CIH group significantly increased, whereas the LV ejection fraction and LV fraction shortening significantly decreased. TEM showed that the myofilaments in the CIH group were loosely arranged, the sarcomere length varied, the cell matrix dissolved, the mitochondrial cristae were partly flocculent, the mitochondrial outer membrane dissolved and disappeared, and some mitochondria were swollen and vacuolated. The histopathological examination showed that the cardiomyocytes in the CIH group were swollen with granular degeneration, some of the myocardial fibers were broken and disorganized, and most of the nuclei were vacuolar and hypochromic.
CONCLUSION
CIH promoted oxidative stress, the influx of Ca, and the activation of the CaN/NFATc signaling pathway, which led to pathological changes in the morphology and ultrastructure of cardiomyocytes, the increase of myocardial apoptosis, and the decrease of myocardial contractility. These changes may be associated with the upregulation of TRPC5.
Topics: Animals; Male; Rats; Apoptosis; Chronic Disease; Disease Models, Animal; Echocardiography; Hypoxia; In Situ Nick-End Labeling; Microscopy, Electron, Transmission; Myocardium; Myocytes, Cardiac; Oxidative Stress; Random Allocation; Rats, Sprague-Dawley; TRPC Cation Channels
PubMed: 38703717
DOI: 10.1016/j.clinsp.2024.100368 -
Medicine May 2024Familial hypertrophic cardiomyopathy (FHCM) is an inherited cardiac disease caused by mutations of sarcomere proteins and can be the underlining substrate for major... (Review)
Review
Familial hypertrophic cardiomyopathy (FHCM) is an inherited cardiac disease caused by mutations of sarcomere proteins and can be the underlining substrate for major cardiovascular events. Early identification and diagnosis of FHCM are essential to reduce sudden cardiac death. So, this paper summarized the current knowledge on FHCM, and displayed the analysis via bibliometrics method. The relevant literature on FHCM were screened searched via the Web of Science Core Collection database from 2012 to 2022. The literatures were was summarized and analyzed via the bibliometrics method analyzed via CiteSpace and VOSviewer according to topic categories, distribution of spatiotemporal omics and authors, as well as references. Since 2012, there are 909 research articles and reviews related to FHCM. The number of publication for the past 10 years have shown that the development of FHCM research has been steady, with the largest amount of literature in 2012. The most published papers were from the United States, followed by the United Kingdom and Italy. The University of London (63 papers) was the institution that published the most research articles, followed by Harvard University (45 papers) and University College London (45 papers). Keywords formed 3 clusters, focused on the pathogenesis of FHCM, the diagnosis of FHCM, FHCM complications, respectively. The bibliometric analysis and visualization techniques employed herein highlight key trends and focal points in the field, predominantly centered around FHCM's pathogenesis, diagnostic approaches, and its complications. These insights are instrumental in steering future research directions in this area.
Topics: Bibliometrics; Humans; Cardiomyopathy, Hypertrophic, Familial; Biomedical Research
PubMed: 38701258
DOI: 10.1097/MD.0000000000037969 -
PloS One 2024Myogenesis is regulated mainly by transcription factors known as Myogenic Regulatory Factors (MRFs), and the transcription is affected by epigenetic modifications....
Myogenesis is regulated mainly by transcription factors known as Myogenic Regulatory Factors (MRFs), and the transcription is affected by epigenetic modifications. However, the epigenetic regulation of myogenesis is poorly understood. Here, we focused on the epigenomic modification enzyme, PHF2, which demethylates histone 3 lysine 9 dimethyl (H3K9me2) during myogenesis. Phf2 mRNA was expressed during myogenesis, and PHF2 was localized in the nuclei of myoblasts and myotubes. We generated Phf2 knockout C2C12 myoblasts using the CRISPR/Cas9 system and analyzed global transcriptional changes via RNA-sequencing. Phf2 knockout (KO) cells 2 d post differentiation were subjected to RNA sequencing. Gene ontology (GO) analysis revealed that Phf2 KO impaired the expression of the genes related to skeletal muscle fiber formation and muscle cell development. The expression levels of sarcomeric genes such as Myhs and Mybpc2 were severely reduced in Phf2 KO cells at 7 d post differentiation, and H3K9me2 modification of Mybpc2, Mef2c and Myh7 was increased in Phf2 KO cells at 4 d post differentiation. These findings suggest that PHF2 regulates sarcomeric gene expression via epigenetic modification.
Topics: Animals; Mice; Cell Differentiation; Cell Line; Epigenesis, Genetic; Gene Knockout Techniques; Histone Demethylases; Histones; MEF2 Transcription Factors; Muscle Development; Muscle Fibers, Skeletal; Myoblasts; Myosin Heavy Chains; Sarcomeres; Transcription Factors; Transcription, Genetic
PubMed: 38701072
DOI: 10.1371/journal.pone.0301690 -
APL Bioengineering Jun 2024Cardiac tissue engineering has emerged as a promising approach for restoring the functionality of damaged cardiac tissues following myocardial infarction. To effectively...
Cardiac tissue engineering has emerged as a promising approach for restoring the functionality of damaged cardiac tissues following myocardial infarction. To effectively replicate the native anisotropic structure of cardiac tissues , this study focused on the fabrication of micropatterned gelatin methacryloyl hydrogels with varying geometric parameters. These substrates were evaluated for their ability to guide induced pluripotent stem cell-derived cardiomyocytes (CMs). The findings demonstrate that the mechanical properties of this hydrogel closely resemble those of native cardiac tissues, and it exhibits high fidelity in micropattern fabrication. Micropatterned hydrogel substrates lead to enhanced organization, maturation, and contraction of CMs. A microgroove with 20-m-width and 20-m-spacing was identified as the optimal configuration for maximizing the contact guidance effect, supported by analyses of nuclear orientation and F-actin organization. Furthermore, this specific micropattern design was found to promote CMs' maturation, as evidenced by increased expression of connexin 43 and vinculin, along with extended sarcomere length. It also enhanced CMs' contraction, resulting in larger contractile amplitudes and greater contractile motion anisotropy. In conclusion, these results underscore the significant benefits of optimizing micropatterned gelatin methacryloyl for improving CMs' organization, maturation, and contraction. This valuable insight paves the way for the development of highly organized and functionally mature cardiac tissues .
PubMed: 38699629
DOI: 10.1063/5.0182585 -
Frontiers in Genetics 2024Previous studies have shown that endoplasmic reticulum stress (ERS) -induced apoptosis is involved in the pathogenesis of dilated cardiomyopathy (DCM). However, the...
Previous studies have shown that endoplasmic reticulum stress (ERS) -induced apoptosis is involved in the pathogenesis of dilated cardiomyopathy (DCM). However, the molecular mechanism involved has not been fully characterized. In total, eight genes were obtained at the intersection of 1,068 differentially expressed genes (DEGs) from differential expression analysis between DCM and healthy control (HC) samples, 320 module genes from weighted gene co-expression network analysis (WGCNA), and 2,009 endoplasmic reticulum stress (ERGs). These eight genes were found to be associated with immunity and angiogenesis. Four of these genes were related to apoptosis. The upregulation of MX1 may represent an autocompensatory response to DCM caused by a virus that inhibits viral RNA and DNA synthesis, while acting as an autoimmune antigen and inducing apoptosis. The upregulation of TESPA1 would lead to the dysfunction of calcium release from the endoplasmic reticulum. The upregulation of THBS4 would affect macrophage differentiation and apoptosis, consistent with inflammation and fibrosis of cardiomyocytes in DCM. The downregulation of MYH6 would lead to dysfunction of the sarcomere, further explaining cardiac remodeling in DCM. Moreover, the expression of genes affecting the immune micro-environment was significantly altered, including TGF-β family member. Analysis of the co-expression and competitive endogenous RNA (ceRNA) network identified XIST, which competitively binds seven target microRNAs (miRNAs) and regulates MX1 and THBS4 expression. Finally, bisphenol A and valproic acid were found to target MX1, MYH6, and THBS4. We have identified four ERS-related genes (MX1, MYH6, TESPA1, and THBS4) that are dysregulated in DCM and related to apoptosis. This finding should help deepen understanding of the role of endoplasmic reticulum stress-induced apoptosis in the development of DCM.
PubMed: 38699233
DOI: 10.3389/fgene.2024.1366087 -
ELife May 2024Here, we investigated the mechanisms by which aging-related reductions of the levels of in skeletal muscle fibers contribute to loss of muscle strength and power, two...
Here, we investigated the mechanisms by which aging-related reductions of the levels of in skeletal muscle fibers contribute to loss of muscle strength and power, two critical features of sarcopenia. Numb is an adaptor protein best known for its critical roles in development, including asymmetric cell division, cell-type specification, and termination of intracellular signaling. expression is reduced in old humans and mice. We previously showed that, in mouse skeletal muscle fibers, Numb is localized to sarcomeres where it is concentrated near triads; conditional inactivation of and a closely related protein -like () in mouse myofibers caused weakness, disorganization of sarcomeres, and smaller mitochondria with impaired function. Here, we found that a single knockout of in myofibers causes reduction in tetanic force comparable to a double , knockout. We found by proteomics analysis of protein complexes isolated from C2C12 myotubes by immunoprecipitation using antibodies against Numb that Septin 7 is a potential Numb-binding partner. Septin 7 is a member of the family of GTP-binding proteins that organize into filaments, sheets, and rings, and is considered part of the cytoskeleton. Immunofluorescence evaluation revealed a partial overlap of staining for Numb and Septin 7 in myofibers. Conditional, inducible knockouts of led to disorganization of Septin 7 staining in myofibers. These findings indicate that Septin 7 is a Numb-binding partner and suggest that interactions between Numb and Septin 7 are critical for structural organization of the sarcomere and muscle contractile function.
Topics: Animals; Septins; Sarcomeres; Mice; Muscle Contraction; Mice, Knockout; Membrane Proteins; Nerve Tissue Proteins; Protein Binding; Muscle Fibers, Skeletal; Intracellular Signaling Peptides and Proteins
PubMed: 38695862
DOI: 10.7554/eLife.89424 -
American Journal of Physiology. Cell... May 2024Skeletal muscle mediates the beneficial effects of exercise, thereby improving insulin sensitivity and reducing the risk for type 2 diabetes. Current human skeletal...
Skeletal muscle mediates the beneficial effects of exercise, thereby improving insulin sensitivity and reducing the risk for type 2 diabetes. Current human skeletal muscle models in vitro are incapable of fully recapitulating its physiological functions especially muscle contractility. By supplementation of insulin-like growth factor 1 (IGF1), a growth factor secreted by myofibers in vivo, we aimed to overcome these limitations. We monitored the differentiation process starting from primary human CD56-positive myoblasts in the presence/absence of IGF1 in serum-free medium in daily collected samples for 10 days. IGF1-supported differentiation formed thicker multinucleated myotubes showing physiological contraction upon electrical pulse stimulation (EPS) following . Myotubes without IGF1 were almost incapable of contraction. IGF1 treatment shifted the proteome toward skeletal muscle-specific proteins that contribute to myofibril and sarcomere assembly, striated muscle contraction, and ATP production. Elevated PPARGC1A, MYH7, and reduced MYH1/2 suggest a more oxidative phenotype further demonstrated by higher abundance of proteins of the respiratory chain and elevated mitochondrial respiration. IGF1-treatment also upregulated glucose transporter (GLUT)4 and increased insulin-dependent glucose uptake compared with myotubes differentiated without IGF1. To conclude, addition of IGF1 to serum-free medium significantly improves the differentiation of human myotubes that showed enhanced myofibril formation, response to electrical pulse stimulation, oxidative respiratory capacity, and glucose metabolism overcoming limitations of previous standards. This novel protocol enables investigation of muscular exercise on a molecular level. Human skeletal muscle models are highly valuable to study how exercise prevents type 2 diabetes without invasive biopsies. Current models did not fully recapitulate the function of skeletal muscle especially during exercise. By supplementing insulin-like growth factor 1 (IGF1), the authors developed a functional human skeletal muscle model characterized by inducible contractility and increased oxidative and insulin-sensitive metabolism. The novel protocol overcomes the limitations of previous standards and enables investigation of exercise on a molecular level.
Topics: Humans; Muscle Fibers, Skeletal; Insulin-Like Growth Factor I; Cell Differentiation; Muscle Contraction; Phenotype; Cells, Cultured; Glucose Transporter Type 4; Myosin Heavy Chains; Glucose; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Muscle, Skeletal
PubMed: 38690930
DOI: 10.1152/ajpcell.00654.2023 -
The Journal of Clinical Investigation May 2024Proline substitutions within the coiled-coil rod region of the β-myosin gene (MYH7) are the predominant mutations causing Laing distal myopathy (MPD1), an autosomal...
Proline substitutions within the coiled-coil rod region of the β-myosin gene (MYH7) are the predominant mutations causing Laing distal myopathy (MPD1), an autosomal dominant disorder characterized by progressive weakness of distal/proximal muscles. We report that the MDP1 mutation R1500P, studied in what we believe to be the first mouse model for the disease, adversely affected myosin motor activity despite being in the structural rod domain that directs thick filament assembly. Contractility experiments carried out on isolated mutant muscles, myofibrils, and myofibers identified muscle fatigue and weakness phenotypes, an increased rate of actin-myosin detachment, and a conformational shift of the myosin heads toward the more reactive disordered relaxed (DRX) state, causing hypercontractility and greater ATP consumption. Similarly, molecular analysis of muscle biopsies from patients with MPD1 revealed a significant increase in sarcomeric DRX content, as observed in a subset of myosin motor domain mutations causing hypertrophic cardiomyopathy. Finally, oral administration of MYK-581, a small molecule that decreases the population of heads in the DRX configuration, significantly improved the limited running capacity of the R1500P-transgenic mice and corrected the increased DRX state of the myofibrils from patients. These studies provide evidence of the molecular pathogenesis of proline rod mutations and lay the groundwork for the therapeutic advancement of myosin modulators.
Topics: Animals; Mice; Humans; Proline; Distal Myopathies; Amino Acid Substitution; Mutation, Missense; Cardiac Myosins; Myosin Heavy Chains; Female; Male; Mice, Transgenic; Muscle Contraction; Muscle, Skeletal
PubMed: 38690726
DOI: 10.1172/JCI172599