Genetically determined pattern of left ventricular function in normal and hypertensive hearts.
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ABSTRACT:
SUBMITTER: Kovacs A
PROVIDER: S-EPMC8031166 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background Sustained pressure overload leads to changes in cardiac metabolism, function, and structure. Both time course and causal relationships between these changes are not fully understood. Therefore, we studied spontaneously hypertensive rats (SHR) during early hypertension development and compared them to control Wistar Kyoto rats. Methods and Results We serially evaluated myocardial glucose uptake rates (Ki) with dynamic 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography, and ejection fraction and left ventricular mass to body weight ratios with cardiac magnetic resonance imaging in vivo, determined glucose uptake and oxidation rates in isolated perfused hearts, and analyzed metabolites, mammalian target of rapamycin activity and endoplasmic reticulum stress in dissected hearts. When compared with Wistar Kyoto rats, SHR demonstrated increased glucose uptake rates (Ki) in vivo, and reduced ejection fraction as early as 2 months of age when hypertension was established. Isolated perfused SHR hearts showed increased glucose uptake and oxidation rates starting at 1 month. Cardiac metabolite analysis at 2 months of age revealed elevated pyruvate, fatty acyl- and branched chain amino acid-derived carnitines, oxidative stress, and inflammation. Mammalian target of rapamycin activity increased in SHR beginning at 2 months. Left ventricular mass to body weight ratios and endoplasmic reticulum stress were elevated in 5 month-old SHR. Conclusions Thus, in a genetic hypertension model, chronic cardiac pressure overload promptly leads to increased myocardial glucose uptake and oxidation, and to metabolite abnormalities. These coincide with, or precede, cardiac dysfunction while left ventricular hypertrophy develops only later. Myocardial metabolic changes may thus serve as early diagnostic markers for hypertension-induced left ventricular hypertrophy.
| S-EPMC6405673 | biostudies-literature
Project description:ObjectiveCardiac changes of hypertensive pregnancy include left ventricular hypertrophy (LVH) and diastolic dysfunction. These are thought to regress postpartum. We hypothesised that women with a history of hypertensive pregnancy would have altered LV geometry and function when compared with women with only normotensive pregnancies.MethodsIn this cohort study, we analysed echocardiograms of 2637 women who participated in the Family Blood Pressure Program. We compared LV mass and function in women with hypertensive pregnancies with those with normotensive pregnancies.ResultsWomen were evaluated at a mean age of 56 years: 427 (16%) had at least one hypertensive pregnancy; 2210 (84%) had normotensive pregnancies. Compared with women with normotensive pregnancies, women with hypertensive pregnancy had a greater risk of LVH (OR: 1.42; 95% CI 1.01 to 1.99, p=0.05), after adjusting for age, race, research network of the Family Blood Pressure Program, education, parity, BMI, hypertension and diabetes. When duration of hypertension was taken into account, this relationship was no longer significant (OR: 1.19; CI 0.08 to 1.78, p=0.38). Women with hypertensive pregnancies also had greater left atrial size and lower mitral E/A ratio after adjusting for demographic variables. The prevalence of systolic dysfunction was similar between the groups.ConclusionsA history of hypertensive pregnancy is associated with LVH after adjusting for risk factors; this might be explained by longer duration of hypertension. This finding supports current guidelines recommending surveillance of women following a hypertensive pregnancy, and sets the stage for longitudinal echocardiographic studies to further elucidate progression of LV geometry and function after pregnancy.Clinical trial registrationsGENOA- NCT00005269; HyperGEN- NCT00005267; Sapphire- NCT00005270; GenNet- NCT00005268.
| S-EPMC4568146 | biostudies-literature
Project description:ObjectivesThe present study was undertaken to test the hypothesis that gene delivery of BCL2-Associated Athanogene 3 (BAG3) to the heart of mice with left ventricular dysfunction secondary to a myocardial infarction could enhance cardiac performance.BackgroundBAG3 is a 575 amino acid protein that has pleotropic functions in the cell including pro-autophagy and anti-apoptosis. Mutations in BAG3 have been associated with both skeletal muscle dysfunction and familial dilated cardiomyopathy and BAG3 levels are diminished in non-familial heart failure.MethodsEight-week-old C57/BL6 mice underwent ligation of the left coronary artery (MI) or sham surgery (Sham). Eight weeks later, mice in both groups were randomly assigned to receive either a retro-orbital injection of rAAV9-BAG3 (MI-BAG3 or Sham-BAG3) or rAAV9-GFP (MI-GFP or Sham GFP). Mice were sacrificed at 3 weeks post-injection and myocytes were isolated from the left ventricle.ResultsMI-BAG3 mice demonstrated a significantly (p < 0.0001) higher left ventricular ejection fraction (LVEF) 9 days after rAAV9-BAG3 injection with further improvement in LVEF, fractional shortening and stroke volume at 3 weeks post-injection without changes in LV mass or LV volume. Injection of rAAV9-BAG3 had no effect on LVEF in Sham mice. The salutary benefits of rAAV9-BAG3 were also observed in myocytes isolated from MI hearts including improved cell shortening (p<0.05), increased systolic [Ca2+]i, increased [Ca2+]i transient amplitudes and increased maximal ICa amplitude.ImplicationsThe results suggest that BAG3 gene therapy may provide a novel therapeutic option for the treatment of heart failure.
| S-EPMC5289821 | biostudies-literature
Project description:BackgroundIn normal ageing, both vascular and ventricular properties change, and how these affect left ventricular function is not clear.Methods96 subjects (ages 20-79) without cardiovascular disease underwent cardiac magnetic resonance (MR) imaging for measurement of global function, diastolic function (E/A ratio), MR tagging for measurement of torsion to shortening ratio (TSR, ratio of epicardial torsion to endocardial circumferential shortening, with increase in TSR suggesting subendocardial dysfunction relative to the subepicardium), and phase contrast MR imaging measurement of central aortic pulse wave velocity (PWV). The Vicorder device was used to measure carotid to femoral PWV.ResultsUnivariate correlations established that the 4 principal age-related changes in the left ventricular function were: 1) diastolic function: E/A ratio (r: -0.61, p<0.00001); 2) global systolic function: cardiac output (r: -0.49, p<0.00001), 3) structure: end-diastolic volume index (r: -0.39, p<0.0001), and 4) systolic strains: TSR (r: 0.49, p<0.0001). Multiple linear regression analysis showed that age was the dominant factor in predicting changes in cardiac output and E/A ratio (both p<0.01). Increased TSR was significantly related to reduced cardiac output and end-diastolic volume index (p<0.05 and p<0.01 respectively). Measures of vascular stiffness were not significantly related to any of these variables, but increased effective arterial elastance (afterload) was significantly related to reduced E/A ratio (p<0.05).ConclusionsIn this group of normal ageing subjects, afterload but not vascular stiffness is significantly related to diastolic dysfunction. Increased TSR, suggesting relative subendocardial dysfunction, has a significant role in reductions of cardiac output and end-diastolic volume index.
| S-EPMC5073997 | biostudies-literature
Project description:Alterations in myocardial structure and reduced cardiomyocyte adhesions have been previously described in dilated cardiomyopathy (DCM). We studied the transcriptome of cell adhesion molecules in these patients and their relationships with left ventricular (LV) function decay. We also visualized the intercalated disc (ID) structure and organization. The transcriptomic profile of 23 explanted LV samples was analyzed using RNA-sequencing (13 DCM, 10 control [CNT]), focusing on cell adhesion genes. Electron microscopy analysis to visualize ID structural differences and immunohistochemistry experiments of ID proteins was also performed. RT-qPCR and western blot experiments were carried out on ID components. We found 29 differentially expressed genes, most of all, constituents of the ID structure. We found that the expression of GJA3, DSP and CTNNA3 was directly associated with LV ejection fraction (r = 0.741, P = 0.004; r = 0.674, P = 0.011 and r = 0.565, P = 0.044, respectively), LV systolic (P = 0.003, P = 0.003, P = 0.028, respectively) and diastolic dimensions (P = 0.006, P = 0.001, P = 0.025, respectively). Electron microscopy micrographs showed a reduced ID convolution index and immunogold labeling of connexin 46 (GJA gene), desmoplakin (DSP gene) and catenin ?-3 (CTNNA3 gene) proteins in DCM patients. Moreover, we observed that protein and mRNA levels analyzed by RT-qPCR of these ID components were diminished in DCM group. In conclusion, we report significant gene and protein expression changes and found that the ID components GJA3, DSP and CTNNA3 were highly related to LV function. Microscopic observations indicated that ID is structurally compromised in these patients. These findings give new data for understanding the ventricular depression that characterizes DCM, opening new therapeutic perspectives for these critically diseased patients.
| S-EPMC5608295 | biostudies-literature
Project description:We describe the case of a patient with severe hypertensive left ventricular hypertrophy and sustained hemodynamically unstable ventricular tachycardia (VT). Entrainment was demonstrated in the electrophysiological study. Activation mapping and pacemapping identified the location of the intramural reentrant VT with the exit site close to the epicardium. However, VT persisted after ablation at the epicardial exit site. Successful ablation was performed endocardially at the corresponding position.
| S-EPMC4661370 | biostudies-literature
Project description:BackgroundRegional functional left ventricular (LV) assessment using current imaging techniques remains limited. Inward displacement (InD) has been developed as a novel technique to assess regional LV function via measurement of the regional displacement of the LV endocardial border across each of the 17 LV segments. Currently, normal ranges for InD are not available for clinical use. The aim of this study was to validate the normal reference limits of InD in healthy adults across all LV segments.MethodsInD was analyzed in 120 healthy subjects with a normal LV ejection fraction, using the three standard long-axis views obtained during cardiac MRI that quantified the degree of inward endocardial wall motion towards the true LV center of contraction. For all LV segments, InD was measured in mm and expressed as a percentage of the theoretical degree of maximal segment contraction towards the true LV centerline. The arithmetic average InD was obtained for each of the 17 segments. The LV was divided into three regions, obtaining average InD at the LV base (segments 1-6), mid-cavity (segments 7-12) and apex (segments 13-17).ResultsAverage InD was 33.4 ± 4.3%. InD was higher in basal and mid-cavity LV segments (32.8 ± 4.1% and 38.1 ± 5.8%) compared to apical LV segments (28.6 ± 7.7%). Interobserver variability correlations for InD were strong (R = 0.80, p < 0.0001).ConclusionsWe provide clinically meaningful reference ranges for InD in subjects with normal LV function, which will emerge as an important screening and assessment imaging tool for a range of HFrEF therapies.
| S-EPMC10744219 | biostudies-literature
Project description:The dystrophin-glycoprotein complex and the alpha7beta1 integrin are trans-sarcolemmal linkage systems that connect and transduce contractile forces between muscle fibers and the extracellular matrix. alpha7beta1 is the major laminin binding integrin in skeletal muscle. Different functional variants of this integrin are generated by alternative splicing and post-translational modifications such as glycosylation and ADP-ribosylation. Here we report a species-specific difference in alpha7 chains that results from an intra-peptide proteolytic cleavage, by a serine protease, at the 603RRQ605 site. Site-directed mutagenesis of RRQ to GRQ prevents this cleavage. This RRQ sequence in the alpha7 integrin chain is highly conserved among vertebrates but it is absent in mice. Protein structure modeling indicates this cleavage site is located in an open region between the beta-propeller and thigh domains of the alpha7 chain. Compared with the non-cleavable alpha7 chain, the cleaved form enhances cell adhesion and spreading on laminin. Cleavage of the alpha7 chain is elevated upon myogenic differentiation, and this cleavage may be mediated by urokinase-type plasminogen activator. These results suggest proteolytic cleavage is a novel mechanism that regulates alpha7 integrin functions in skeletal muscle, and that the generation of such cleavage sites is another evolutionary mechanism for expanding and modifying protein functions.
| S-EPMC2602887 | biostudies-literature
Project description:The impact of non-sustained ventricular tachycardia (NSVT) on the risk of thromboembolic event and clinical outcomes in patients without structural heart disease remains undetermined. This study aimed to evaluate the association between NSVT and clinical outcomes.The study population of 5903 patients was culled from the "Registry of 24-hour ECG monitoring at Taipei Veterans General Hospital" (REMOTE database) between January 1, 2002 and December 31, 2004. Of that total, we enrolled 3767 patients without sustained ventricular tachycardia, structural heart disease, and permanent pacemaker. For purposes of this study, NSVT was defined as 3 or more consecutive beats arising below the atrioventricular node with an RR interval of <600 ms (>100 beats/min) and lasting < 30 seconds.There were 776 deaths, 2042 hospitalizations for any reason, 638 cardiovascular (CV)-related hospitalizations, 350 ischemic strokes, 409 transient ischemic accident (TIA), 368 new-onset heart failure (HF), and 260 new-onset atrial fibrillation (AF) with a mean follow-up duration of 10 ± 1 years. In multivariate analysis, the presence of NSVT was independently associated with death (hazard ratio [HR]: 1.362, 95% confidence interval [CI]: 1.071-1.731), CV hospitalization (HR: 1.527, 95% CI: 1.171-1.992), ischemic stroke (HR: 1.436, 95% CI: 1.014-2.032), TIA (HR 1.483, 95% CI: 1.069-2.057), and new-onset HF (HR: 1.716, 95% CI: 1.243-2.368). There was no significant association between the presence of NSVT and all-cause hospitalization or new-onset AF.In patients without structural heart disease, presence of NSVT on 24-hour monitoring was independently associated with death, CV hospitalization, ischemic stroke, TIA, and new onset heart failure.
| S-EPMC4993359 | biostudies-literature
Project description:Background: Although brachial-ankle pulse wave velocity (baPWV) is simple and convenient, its usefulness as an initial screening test for hypertensive patients is not well-known. This study aimed to investigate the association of baPWV with left ventricular (LV) geometry and diastolic function in treatment-naive hypertensive patients. Methods: A total of 202 untreated hypertensive patients (mean age, 62 years; males, 51.5%) without documented cardiovascular diseases were prospectively enrolled. Both baPWV and transthoracic echocardiography were performed on the same day before antihypertensive treatment. Results: In multiple linear regression analysis after adjustment for potential confounders, baPWV had significant correlations with structural measurements of LV including relative wall thickness (β = 0.219, P = 0.021) and LV mass index (β = 0.286, P = 0.002), and four diastolic parameters including septal e' velocity (β = -0.199, P = 0.018), E/e' (β = 0.373, P < 0.001), left atrial volume index (β = 0.334, P < 0.001), and maximal velocity of tricuspid regurgitation (β = 0.401, P < 0.001). The baPWV was significantly increased in patients with LV hypertrophy, abnormal LV remodeling, or diastolic dysfunction, compared to those without (P = 0.008, P = 0.035, and P < 0.001, respectively). In the receiver operating characteristic curve analysis, the discriminant ability of baPWV in predicting LV hypertrophy and diastolic dysfunction had an area under the curve of 0.646 (95% confidence interval 0.544-0.703, P = 0.004) and 0.734 (95% confidence interval 0.648-0.800, P < 0.001), respectively. Conclusion: baPWV was associated with parameters of LV remodeling and diastolic function in untreated hypertensive patients. The baPWV could be a useful screening tool for the early detection of adverse cardiac features among untreated hypertensive patients.
| S-EPMC8143267 | biostudies-literature