Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 67
Filter
1.
JACC Basic Transl Sci ; 9(6): 733-750, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39070276

ABSTRACT

Heart failure (HF) with left ventricular diastolic dysfunction is a growing global concern. This study evaluated myocardial oxidized nicotinamide adenine dinucleotide (NAD+) levels in human systolic and diastolic HF and in a murine model of HF with preserved ejection fraction, exploring NAD+ repletion as therapy. We quantified myocardial NAD+ and nicotinamide phosphoribosyltransferase levels, assessing restoration with nicotinamide riboside (NR). Findings show significant NAD+ and nicotinamide phosphoribosyltransferase depletion in human diastolic HF myocardium, but NR successfully restored NAD+ levels. In murine HF with preserved ejection fraction, NR as preventive and therapeutic intervention improved metabolic and antioxidant profiles. This study underscores NAD+ repletion's potential in diastolic HF management.

2.
Tissue Eng Part C Methods ; 30(8): 335-342, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39078321

ABSTRACT

The development of small-diameter vascular grafts requires testing in large animal models before advancing to clinical trials. Vascular graft interposition implantation in sheep carotid arteries (CAs) is the most widely used model, but ovine CAs are prone to severe spasm following surgical manipulation, potentially impairing graft performance assessment. There is paucity in the literature on reducing sheep CA spasm using effective vasodilator therapeutic protocols. In this study, four healthy Merino cross White Suffolk wethers (1-2 years, 52.1 ± 0.8 kg) underwent CT angiography and CA graft surgery. CT angiography using iodinated contrast agent was performed with innominate artery access through the CA or ascending aortic arch access through the femoral artery. Sheep then underwent right CA sham surgery or left CA vascular graft implantation. A variety of vasodilators, including papaverine, sodium nitroprusside, verapamil, and their combination, were tested for preventing or treating CA spasms intraoperatively. Blood flow was reassessed immediately after CA surgery using CT angiography. The results showed that innominate artery access through the CA for CT angiography in sheep induced presurgical CA spasm with reduced arterial flow. Conversely, ascending aortic arch access through the femoral artery for CT angiography did not cause CA spasm and maintained arterial flow. During CA graft surgery, surgical trauma induced CA spasm, which was prevented by localized intra-arterial administration of vasodilators papaverine hydrochloride and verapamil before significant surgical manipulation.


Subject(s)
Carotid Arteries , Computed Tomography Angiography , Animals , Sheep , Carotid Arteries/diagnostic imaging , Carotid Arteries/drug effects , Vasodilator Agents/pharmacology , Vascular Grafting/methods , Female
3.
J Microsc ; 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38856969

ABSTRACT

Immunohistochemistry (IHC) and immunofluorescence (IF) are crucial techniques for studying cardiac physiology and disease. The accuracy of these techniques is dependent on various aspects of sample preparation and processing. However, standardised protocols for sample preparation of tissues, particularly for fresh-frozen human left ventricle (LV) tissue, have yet to be established and could potentially lead to differences in staining and interpretation. Thus, this study aimed to optimise the reproducibility and quality of IF staining in fresh-frozen human LV tissue by systematically investigating crucial aspects of the sample preparation process. To achieve this, we subjected fresh-frozen human LV tissue to different fixation protocols, primary antibody incubation temperatures, antibody penetration reagents, and fluorescent probes. We found that neutral buffered formalin fixation reduced image artefacts and improved antibody specificity compared to both methanol and acetone fixation. Additionally, incubating primary antibodies at 37°C for 3 h improved fluorescence intensity compared to the commonly practised 4°C overnight incubation. Furthermore, we found that DeepLabel, an antibody penetration reagent, and smaller probes, such as fragmented antibodies and Affimers, improved the visualisation depth of cardiac structures. DeepLabel also improved antibody penetration in CUBIC cleared thick LV tissue fragments. Thus, our data underscores the importance of standardised protocols in IF staining and provides various means of improving staining quality. In addition to contributing to cardiac research by providing methodologies for IF, the findings and processes presented herein also establish a framework by which staining of other tissues may be optimised.

4.
Heart Lung Circ ; 33(8): 1227-1231, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38744603

ABSTRACT

BACKGROUND: Cardiogenic shock (CS) is common and survival outcomes have not substantially improved. Australia's geography presents unique challenges in the management of CS. The challenges and research priorities for clinicians pertaining to CS identification and management have yet to be described. METHOD: We used an exploratory sequential mixed methods design. Semi-structured interviews were conducted with 10 clinicians (medical and nursing) to identify themes for quantitative evaluation. A total of 143 clinicians undertook quantitative evaluation through online survey. The interviews and surveys addressed current understanding of CS, status of cardiogenic systems and future research priorities. RESULTS: There were 143 respondents: 16 (11%) emergency, cardiology 22 (16%), 37 (26%) intensive care, 54 (38%) nursing. In total, 107 (75%) believe CS is under-recognised. Thirteen (13; 9%) of respondents indicated their hospital had existing CS teams, all from metropolitan hospitals, and 40% thought additional access to mechanical circulatory support devices was required. Five (5; 11%) non-tertiary hospital respondents had not experienced a delay in transfer of a patient in CS. All respondents felt additional research, particularly into the management of CS, was required. CONCLUSIONS: Clinicians report that CS is under-recognised and further research into CS management is required. Access to specialised CS services is still an issue and CS protocolised pathways may be of value.


Subject(s)
Shock, Cardiogenic , Shock, Cardiogenic/therapy , Humans , Surveys and Questionnaires , Australia , Male , Female
5.
Eur J Heart Fail ; 26(8): 1778-1787, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38714362

ABSTRACT

AIMS: The optimal echocardiographic predictors of cardiovascular outcome in heart failure (HF) with preserved ejection fraction (HFpEF) are unknown. We aimed to identify independent echocardiographic predictors of cardiovascular outcome in patients with HFpEF. METHODS AND RESULTS: Systematic literature search of three electronic databases was conducted from date of inception until November 2022. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for echocardiographic variables from multivariate prediction models for the composite primary endpoint of cardiovascular death and HF hospitalization were pooled using a random effects meta-analysis. Specific subgroup analyses were conducted for studies that enrolled patients with acute versus chronic HF, and for those studies that included E/e', pulmonary artery systolic pressure (PASP), renal function, natriuretic peptides and diuretic use in multivariate models. Forty-six studies totalling 20 056 patients with HFpEF were included. Three echocardiographic parameters emerged as independent predictors in all subgroup analyses: decreased left ventricular (LV) global longitudinal strain (HR 1.24, 95% CI 1.10-1.39 per 5% decrease), decreased left atrial (LA) reservoir strain (HR 1.30, 95% CI 1.13-1.1.50 per 5% decrease) and lower tricuspid annular plane systolic excursion (TAPSE) to PASP ratio (HR 1.17, 95% CI 1.07-1.25 per 0.1 unit decrease). Other independent echocardiographic predictors of the primary endpoint were a higher E/e', moderate to severe tricuspid regurgitation, LV mass index and LA ejection fraction, although these variables were less robust. CONCLUSIONS: Impaired LV global longitudinal strain, lower LA reservoir strain and lower TAPSE/PASP ratio predict cardiovascular death and HF hospitalization in HFpEF and are independent of filling pressures, clinical characteristics and natriuretic peptides. These echocardiographic parameters reflect key functional changes in HFpEF, and should be incorporated in future prospective risk prediction models.


Subject(s)
Echocardiography , Heart Failure , Stroke Volume , Humans , Echocardiography/methods , Heart Failure/complications , Heart Failure/mortality , Heart Failure/physiopathology , Heart Ventricles/physiopathology , Heart Ventricles/diagnostic imaging , Hospitalization/statistics & numerical data , Prognosis , Stroke Volume/physiology , Ventricular Function, Left/physiology
6.
Eur Heart J Case Rep ; 8(3): ytae129, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38638283

ABSTRACT

Background: Desmoplakin (DSP) cardiomyopathy is a rare genetic condition characterized by repeated inflammatory myocardial injury and is associated with ventricular arrhythmia and sudden cardiac death. Diagnosis is challenging and requires a combination of genetic testing and advanced imaging techniques. Case summary: We present the case of a 38-year-old woman with recurrent episodes of subclinical myocarditis. Investigation using cardiac magnetic resonance imaging (cMRI) and genetic testing revealed a diagnosis of DSP cardiomyopathy. Her disease was initially responsive to corticosteroid therapy but quickly relapsed when treatment was tapered. Management of her condition required significant immunosuppression and the subsequent insertion of an implantable cardiac defibrillator due to her risk of sudden cardiac death. Discussion: Cardiac MRI and genetic testing are key diagnostic techniques in the assessment of patients with recurrent myocarditis and cardiomyopathy. The management of cardiomyopathies with an inflammatory component is not completely understood; however, there is likely a key role for immune suppression therapies. Furthermore, there are several cardiomyopathy genetic variants including DSP which require careful risk stratification due to an increased risk of sudden cardiac death.

7.
NPJ Genom Med ; 8(1): 29, 2023 Oct 11.
Article in English | MEDLINE | ID: mdl-37821546

ABSTRACT

There is an incomplete understanding of the burden of splice-disrupting variants in definitively associated inherited heart disease genes and whether these genes can amplify from blood RNA to support functional confirmation of splicing outcomes. We performed burden testing of rare splice-disrupting variants in people with inherited heart disease and sudden unexplained death compared to 125,748 population controls. ClinGen definitively disease-associated inherited heart disease genes were amplified using RNA extracted from fresh blood, derived cardiomyocytes, and myectomy tissue. Variants were functionally assessed and classified for pathogenicity. We found 88 in silico-predicted splice-disrupting variants in 128 out of 1242 (10.3%) unrelated participants. There was an excess burden of splice-disrupting variants in PKP2 (5.9%), FLNC (2.7%), TTN (2.8%), MYBPC3 (8.2%) and MYH7 (1.3%), in distinct cardiomyopathy subtypes, and KCNQ1 (3.6%) in long QT syndrome. Blood RNA supported the amplification of 21 out of 31 definitive disease-associated inherited heart disease genes. Our functional studies confirmed altered splicing in six variants. Eleven variants of uncertain significance were reclassified as likely pathogenic based on functional studies and six were used for cascade genetic testing in 12 family members. Our study highlights that splice-disrupting variants are a significant cause of inherited heart disease, and that analysis of blood RNA confirms splicing outcomes and supports variant pathogenicity classification.

8.
J Mol Cell Cardiol ; 185: 26-37, 2023 12.
Article in English | MEDLINE | ID: mdl-37797718

ABSTRACT

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiac disease. Up to 40% of cases are associated with heterozygous mutations in myosin binding protein C (cMyBP-C, MYBPC3). Most of these mutations lead to premature termination codons (PTC) and patients show reduction of functional cMyBP-C. This so-called haploinsufficiency most likely contributes to disease development. We analyzed mechanisms underlying haploinsufficiency using cardiac tissue from HCM-patients with truncation mutations in MYBPC3 (MYBPC3trunc). We compared transcriptional activity, mRNA and protein expression to donor controls. To differentiate between HCM-specific and general hypertrophy-induced mechanisms we used patients with left ventricular hypertrophy due to aortic stenosis (AS) as an additional control. We show that cMyBP-C haploinsufficiency starts at the mRNA level, despite hypertrophy-induced increased transcriptional activity. Gene set enrichment analysis (GSEA) of RNA-sequencing data revealed an increased expression of NMD-components. Among them, Up-frameshift protein UPF3B, a regulator of NMD was upregulated in MYBPC3trunc patients and not in AS-patients. Strikingly, we show that in sarcomeres UPF3B but not UPF1 and UPF2 are localized to the Z-discs, the presumed location of sarcomeric protein translation. Our data suggest that cMyBP-C haploinsufficiency in HCM-patients is established by UPF3B-dependent NMD during the initial translation round at the Z-disc.


Subject(s)
Cardiomyopathy, Hypertrophic , Myocytes, Cardiac , Humans , Cardiomyopathy, Hypertrophic/metabolism , Haploinsufficiency , Hypertrophy/metabolism , Mutation , Myocytes, Cardiac/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA-Binding Proteins/metabolism
9.
Basic Res Cardiol ; 118(1): 39, 2023 09 29.
Article in English | MEDLINE | ID: mdl-37775647

ABSTRACT

Giant mitochondria are frequently observed in different disease models within the brain, kidney, and liver. In cardiac muscle, these enlarged organelles are present across diverse physiological and pathophysiological conditions including in ageing and exercise, and clinically in alcohol-induced heart disease and various cardiomyopathies. This mitochondrial aberration is widely considered an early structural hallmark of disease leading to adverse organ function. In this thematic paper, we discuss the current state-of-knowledge on the presence, structure and functional implications of giant mitochondria in heart muscle. Despite its demonstrated reoccurrence in different heart diseases, the literature on this pathophysiological phenomenon remains relatively sparse since its initial observations in the early 60s. We review historical and contemporary investigations from cultured cardiomyocytes to human tissue samples to address the role of giant mitochondria in cardiac health and disease. Finally, we discuss their significance for the future development of novel mitochondria-targeted therapies to improve cardiac metabolism and functionality.


Subject(s)
Cardiomyopathies , Myocytes, Cardiac , Humans , Myocytes, Cardiac/metabolism , Mitochondrial Swelling , Mitochondria/metabolism , Myocardium/metabolism , Mitochondria, Heart/metabolism
10.
Heart Vessels ; 38(12): 1476-1485, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37608153

ABSTRACT

To demonstrate that point-of-care multimodal spectroscopy using Near-Infrared (NIR) and Raman Spectroscopy (RS) can be used to diagnose human heart tissue. We generated 105 spectroscopic scans, which comprised 4 NIR and 3 RS scans per sample to generate a "multimodal spectroscopic scan" (MSS) for each heart, done across 15 patients, 5 each from the dilated cardiomyopathy (DCM), Ischaemic Heart Disease (IHD) and Normal pathologies. Each of the MSS scans was undertaken in 3 s. Data were entered into machine learning (ML) algorithms to assess accuracy of MSS in diagnosing tissue type. The median age was 50 years (IQR 49-52) for IHD, 47 (IQR 45-50) for DCM and 36 (IQR 33-52) for healthy patients (p = 0.35), 60% of which were male. MSS identified key differences in IHD, DCM and normal heart samples in regions typically associated with fibrosis and collagen (NIR wavenumbers: 1433, 1509, 1581, 1689 and 1725 nm; RS wavelengths: 1658, 1450 and 1330 cm-1). In principal component (PC) analyses, these differences explained 99.2% of the variation in 4 PCs for NIR, 81.6% in 10 PCs for Raman, and 99.0% in 26 PCs for multimodal spectroscopic signatures. Using a stack machine learning algorithm with combined NIR and Raman data, our model had a precision of 96.9%, recall of 96.6%, specificity of 98.2% and Area Under Curve (AUC) of 0.989 (Table 1). NIR and Raman modalities alone had similar levels of precision at 94.4% and 89.8% respectively (Table 1). MSS combined with ML showed accuracy of 90% for detecting dilated cardiomyopathy, 100% for ischaemic heart disease and 100% for diagnosing healthy tissue. Multimodal spectroscopic signatures, based on NIR and Raman spectroscopy, could provide cardiac tissue scans in 3-s to aid accurate diagnoses of fibrosis in IHD, DCM and normal hearts. Table 1 Machine learning performance metrics for validation data sets of (a) Near-Infrared (NIR), (b) Raman and (c and d) multimodal data using logistic regression (LR), stochastic gradient descent (SGD) and support vector machines (SVM), with combined "stack" (LR + SGD + SVM) AUC Precision Recall Specificity (a) NIR model  Logistic regression 0.980 0.944 0.933 0.967  SGD 0.550 0.281 0.400 0.700  SVM 0.840 0.806 0.800 0.900  Stack 0.933 0.794 0.800 0.900 (b) Raman model  Logistic regression 0.985 0.940 0.929 0.960  SGD 0.892 0.869 0.857 0.932  SVM 0.992 0.940 0.929 0.960  Stack 0.954 0.869 0.857 0.932 (c) MSS: multimodal (NIR + Raman) to detect DCM vs. IHD vs. normal patients  Logistic regression 0.975 0.841 0.828 0.917  SGD 0.847 0.803 0.793 0.899  SVM 0.971 0.853 0.828 0.917  Stack 0.961 0.853 0.828 0.917 (d) MSS: multimodal (NIR + Raman) to detect pathological vs. normal patients  Logistic regression 0.961 0.969 0.966 0.984  SGD 0.944 0.967 0.966 0.923  SVM 1.000 1.000 1.000 1.000  Stack 1.000 0.944 0.931 0.969 Bold values indicate values obtained from the stack algorithm and used for analyses.


Subject(s)
Cardiomyopathy, Dilated , Myocardial Ischemia , Humans , Male , Middle Aged , Female , Spectroscopy, Near-Infrared/methods , Cardiomyopathy, Dilated/diagnosis , Point-of-Care Systems , Algorithms , Fibrosis
13.
J Cardiovasc Dev Dis ; 10(5)2023 Apr 23.
Article in English | MEDLINE | ID: mdl-37233155

ABSTRACT

Peripartum cardiomyopathy (PPCM) is a rare form of acute onset heart failure that presents in otherwise healthy pregnant women around the time of delivery. While most of these women respond to early intervention, about 20% progress to end-stage heart failure that symptomatically resembles dilated cardiomyopathy (DCM). In this study, we examined two independent RNAseq datasets from the left ventricle of end-stage PPCM patients and compared gene expression profiles to female DCM and non-failing donors. Differential gene expression, enrichment analysis and cellular deconvolution were performed to identify key processes in disease pathology. PPCM and DCM display similar enrichment in metabolic pathways and extracellular matrix remodeling suggesting these are similar processes across end-stage systolic heart failure. Genes involved in golgi vesicles biogenesis and budding were enriched in PPCM left ventricles compared to healthy donors but were not found in DCM. Furthermore, changes in immune cell populations are evident in PPCM but to a lesser extent compared to DCM, where the latter is associated with pronounced pro-inflammatory and cytotoxic T cell activity. This study reveals several pathways that are common to end-stage heart failure but also identifies potential targets of disease that may be unique to PPCM and DCM.

14.
Heart Fail Rev ; 28(4): 949-959, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36198840

ABSTRACT

Women have been historically underrepresented in clinical trials of heart failure (HF). We aimed to assess for sex differences in patient characteristics and the efficacy of guideline-directed medical therapy (GDMT) in HF. Systematic literature search for randomized controlled trials (RCTs) of GDMT reporting cardiovascular outcomes by sex in patients with HF. The primary outcome was the composite of cardiovascular death and hospitalization for HF. Risk ratios (RR) with 95% confidence intervals (CI) were pooled using inverse variance weighting and random effects meta-analysis. Twenty-six RCTs totaling 84,818 participants (27% women) were included. Women with HF were older, had higher New York Heart Association (NYHA) class, more hypertension and obesity, and higher mean left ventricular ejection fraction compared to men. There was evidence for most GDMT in reducing the primary outcome in women with HF with reduced ejection fraction (HFrEF) (angiotensin-converting enzyme inhibitors/angiotensin-receptor blocker [RR 0.86, 95% CI 0.75-0.97], angiotensin-receptor blocker/neprilysin inhibitor (ARNI) [RR 0.77, 95% CI 0.62-0.94], beta-blocker [RR 0.67, 95% CI 0.51-0.89], ivabradine [RR 0.74, 95% CI 0.60-0.91], and sodium-glucose cotransporter-2 (SGLT2) inhibitors [RR 0.66, 95% CI 0.54-0.81]) and a non-significant trend for benefit with mineralocorticoid-receptor-antagonist (MRA) [RR 0.77, 95% CI 0.52-1.16]). Compared to men with HFrEF, GDMT reduced the primary outcome in women to a similar degree across all drug classes (ratio of RR 1.05, 95% CI 0.96-1.14). Despite differences in baseline characteristics and an underrepresentation of women in HF clinical trials, GDMT are as efficacious in women as compared to men in reducing cardiovascular events in HF.


Subject(s)
Heart Failure , Sex Characteristics , Male , Female , Humans , Heart Failure/drug therapy , Ivabradine , Angiotensin Receptor Antagonists , Stroke Volume , Angiotensins
15.
Nat Cardiovasc Res ; 2(2): 159-173, 2023 Feb.
Article in English | MEDLINE | ID: mdl-39196058

ABSTRACT

Muscle contraction is driven by the molecular machinery of the sarcomere. As phosphorylation is a critical regulator of muscle function, the identification of regulatory kinases is important for understanding sarcomere biology. Pathogenic variants in alpha kinase 3 (ALPK3) cause cardiomyopathy and musculoskeletal disease, but little is known about this atypical kinase. Here we show that ALPK3 is an essential component of the M-band of the sarcomere and define the ALPK3-dependent phosphoproteome. ALPK3 deficiency impaired contractility both in human cardiac organoids and in the hearts of mice harboring a pathogenic truncating Alpk3 variant. ALPK3-dependent phosphopeptides were enriched for sarcomeric components of the M-band and the ubiquitin-binding protein sequestosome-1 (SQSTM1) (also known as p62). Analysis of the ALPK3 interactome confirmed binding to M-band proteins including SQSTM1. In human pluripotent stem cell-derived cardiomyocytes modeling cardiomyopathic ALPK3 mutations, sarcomeric organization and M-band localization of SQSTM1 were abnormal suggesting that this mechanism may underly disease pathogenesis.

16.
Int J Cardiol ; 363: 179-184, 2022 09 15.
Article in English | MEDLINE | ID: mdl-35724800

ABSTRACT

AIMS: To identify biomarkers of cardiomyopathy in patients with type 2 diabetes mellitus (T2DM) using cardiovascular magnetic resonance (CMR) and to identify associations between functional status, metabolomic profile and myocardial fibrosis. METHODS: In this prospective case control study, patients (n = 49) with T2DM without significant coronary artery disease, and matched controls (n = 18) underwent CMR, cardiopulmonary exercise testing, and plasma metabolomic analyses. RESULTS: Patients with T2DM (n = 49, median [interquartile range] age 61 [56-63] years, 61% male, diabetes duration 11 [7-20] years), historical HbA1c 7.6% (60 mmol/mol) (6.9-8.6) and matched controls (n = 18) were examined. Study patients had increased myocardial extracellular volume (ECV) (26.9 [23.8-30.0] vs 23.4 [22.4-25.5) %, p < 0.001). Increased ECV was associated with male sex (p = 0.04), time with T2DM (p = 0.02), reduced peak VO2 (R2 = 0.48, p = 0.01), increased circulating choline (p = 0.002) and cysteamine (p = 0.002) both of which were also associated with reduced peak VO2 (p < 0.025 and 0.014 respectively). CONCLUSIONS: Patients with well-controlled T2DM without significant coronary disease exhibit focal and diffuse myocardial fibrosis and diffuse myocardial fibrosis is associated with reduced exercise tolerance and metabolites. Plasma metabolites may provide mechanistic insights into diffuse myocardial fibrosis, and cardiopulmonary fitness.


Subject(s)
Cardiomyopathies , Coronary Artery Disease , Diabetes Mellitus, Type 2 , Cardiomyopathies/complications , Cardiomyopathies/diagnostic imaging , Case-Control Studies , Coronary Artery Disease/complications , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/pathology , Female , Fibrosis , Humans , Magnetic Resonance Imaging, Cine , Male , Middle Aged , Myocardium/pathology , Predictive Value of Tests , Ventricular Function, Left
17.
Trends Cardiovasc Med ; 32(1): 20-31, 2022 01.
Article in English | MEDLINE | ID: mdl-33338638

ABSTRACT

Atrial fibrillation (AF) is a common arrhythmia that can lead to stroke. The diseased muscle tissue of the atria develops atrial fibrosis, inflammation, thrombosis and subsequent strokes, resulting in significant morbidity and mortality. Current diagnostic and evaluation paradigms for clinical AF focus on identifying functional and morphological abnormalities of the left atria by echocardiography. Notably, the development of atrial substrate that marks AF likely occurs for years before the manifestation of AF onset, meaning that the functional and morphometrical aberrations are end-stage features, representing a stable state of an already-compromised tissue. There is no existing 'gold standard' measure to identify the early atrial muscle disease and characterization of the atrial substrate is inadequate. In fact, sub-clinical identification of atrial myopathy is not undertaken in clinical practice because there is no robust screening method. Development of molecular imaging probes for detection of atrial muscle disease might enable early detection and staging of AF, ultimately leading to improved treatment outcome. In this review, we discuss possible molecular imaging targets that may enable early diagnosis of cardiovascular disease, with focus on novel insights, challenges and opportunities for sub-clinical imaging of atrial myopathy and AF.


Subject(s)
Atrial Fibrillation , Muscular Diseases , Atrial Fibrillation/diagnostic imaging , Atrial Fibrillation/therapy , Disease Management , Early Diagnosis , Heart Atria/diagnostic imaging , Humans , Molecular Imaging
18.
Cardiovasc Res ; 118(1): 241-253, 2022 01 07.
Article in English | MEDLINE | ID: mdl-33135063

ABSTRACT

AIMS: Dilated cardiomyopathy (DCM) is associated with mutations in many genes encoding sarcomere proteins. Truncating mutations in the titin gene TTN are the most frequent. Proteomic and functional characterizations are required to elucidate the origin of the disease and the pathogenic mechanisms of TTN-truncating variants. METHODS AND RESULTS: We isolated myofibrils from DCM hearts carrying truncating TTN mutations and measured the Ca2+ sensitivity of force and its length dependence. Simultaneous measurement of force and adenosine triphosphate (ATP) consumption in skinned cardiomyocytes was also performed. Phosphorylation levels of troponin I (TnI) and myosin binding protein-C (MyBP-C) were manipulated using protein kinase A and λ phosphatase. mRNA sequencing was employed to overview gene expression profiles. We found that Ca2+ sensitivity of myofibrils carrying TTN mutations was significantly higher than in myofibrils from donor hearts. The length dependence of the Ca2+ sensitivity was absent in DCM myofibrils with TTN-truncating variants. No significant difference was found in the expression level of TTN mRNA between the DCM and donor groups. TTN exon usage and splicing were also similar. However, we identified down-regulation of genes encoding Z-disk proteins, while the atrial-specific regulatory myosin light chain gene, MYL7, was up-regulated in DCM patients with TTN-truncating variants. CONCLUSION: Titin-truncating mutations lead to decreased length-dependent activation and increased elasticity of myofibrils. Phosphorylation levels of TnI and MyBP-C seen in the left ventricles are essential for the length-dependent changes in Ca2+ sensitivity in healthy donors, but they are reduced in DCM patients with TTN-truncating variants. A decrease in expression of Z-disk proteins may explain the observed decrease in myofibril passive stiffness and length-dependent activation.


Subject(s)
Cardiomyopathy, Dilated/metabolism , Carrier Proteins/metabolism , Connectin/metabolism , Myocardial Contraction , Myocytes, Cardiac/metabolism , Myofibrils/metabolism , Troponin I/metabolism , Adult , Cardiomyopathy, Dilated/genetics , Cardiomyopathy, Dilated/pathology , Cardiomyopathy, Dilated/physiopathology , Connectin/genetics , Cyclic AMP-Dependent Protein Kinases/metabolism , Female , Genetic Predisposition to Disease , Humans , Kinetics , Male , Middle Aged , Mutation , Myofibrils/pathology , Phenotype , Phosphoprotein Phosphatases/metabolism , Phosphorylation , Viral Proteins/metabolism , Young Adult
20.
ESC Heart Fail ; 9(1): 21-30, 2022 02.
Article in English | MEDLINE | ID: mdl-34931483

ABSTRACT

Biobanking in health care has evolved over the last few decades from simple biological sample repositories to complex and dynamic units with multi-organizational infrastructure networks and has become an essential tool for modern medical research. Cardiovascular tissue biobanking provides a unique opportunity to utilize cardiac and vascular samples for translational research into heart failure and other related pathologies. Current techniques for diagnosis, classification, and treatment monitoring of cardiac disease relies primarily on interpretation of clinical signs, imaging, and blood biomarkers. Further research at the disease source (i.e. myocardium and blood vessels) has been limited by a relative lack of access to quality human cardiac tissue and the inherent shortcomings of most animal models of heart disease. In this review, we describe a model for cardiovascular tissue biobanking and databasing, and its potential to facilitate basic and translational research. We share techniques to procure endocardial samples from patients with hypertrophic cardiomyopathy, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction, in addition to aortic disease samples. We discuss some of the issues with respect to data collection, privacy, biobank consent, and the governance of tissue biobanking. The development of tissue biobanks as described here has significant scope to improve and facilitate translational research in multi-omic fields such as genomics, transcriptomics, proteomics, and metabolomics. This research heralds an era of precision medicine, in which patients with cardiovascular pathology can be provided with optimized and personalized medical care for the treatment of their individual phenotype.


Subject(s)
Biological Specimen Banks , Biomedical Research , Animals , Genomics , Humans , Precision Medicine , Translational Research, Biomedical
SELECTION OF CITATIONS
SEARCH DETAIL