Impaired Cardiac Diastolic Function Research Articles

Hydrogen Sulfide Ameliorates Heart Aging by Downregulating Matrix Metalloproteinase-9.

Aging contributes significantly to cardiovascular diseases and cardiac dysfunction, leading to the upregulation of matrix metalloproteinase-9 (MMP-9) in the heart and a significant decrease in hydrogen sulfide (H2S) content, coupled with impaired cardiac diastolic function. This study explores whether supplementing exogenous hydrogen sulfide during aging ameliorates the decline in H2S concentration in the heart, suppresses MMP-9 expression, and improves the age-associated impairment in cardiac morphology and function. We collected plasma from healthy individuals of different ages to determine the relationship between aging and H2S and MMP-9 levels through Elisa detection and liquid chromatography-tandem mass spectrometry (LC/MC) detection of plasma H2S content. Three-month-old mice were selected as the young group, while 18-month-old mice were selected as the old group, and sodium hydrosulfide (NaHS) was injected intraperitoneally from 15 months old until 18 months old as the old + NaHS group. Plasma MMP-9 content was detected using Elisa, plasma H2S content, cardiac H2S content, and cystathionine gamma-lyase (CSE) activity were detected using LC/MC, and cardiac function was detected using echocardiography. Heart structure was assessed using hematoxylin and eosin staining, Masone staining was used to detect the degree of cardiac fibrosis, while western blot was used to detect the expression of MMP-9, CSE, and aging marker proteins. Knockdown of MMP-9 and CSE in H9c2 cells using small interfering RNA was carried out to determine the upstream-downstream relationship between MMP-9 and CSE. H2S content in the plasma of healthy individuals decreases with escalating age, whereas MMP-9 level rises with age progression. Aging leads to a decrease in H2S levels in the heart and plasma of mice, severe impairment of cardiac diastolic function, interstitial relaxation, and fibrosis of the heart. Supplementing with exogenous H2S can improve these phenomena. H2S maintains the structure and function of the heart by inhibiting the expression of MMP-9 during the aging process.

Sudomotor dysfunction is associated with impaired left ventricular diastolic function in persons with type 2 diabetes: a cross-sectional study.

The incidence of preserved ejection fraction heart failure has significantly increased in persons with type 2 diabetes mellitus (T2DM). Left ventricular (LV) diastolic dysfunction is an early and important manifestation of preserved ejection fraction heart failure. The onset of heart failure in persons with diabetes is associated with diabetic neuropathy. However, the relationship among sudomotor function, which is an early manifestation of small fiber neuropathy, and LV diastolic function remains unclear. This study aimed to explore the association between sudomotor function and LV diastolic function in persons with T2DM. In total, 699 persons with T2DM were enrolled and divided into three groups according to electrochemical skin conductance (ESC) assessed using the SUDOSCAN device: "no dysfunction" group (NSF), "moderate dysfunction" group (MDF), and "severe dysfunction" group (SDF). LV diastolic function was assessed using Doppler echocardiography. To evaluate the relationship between ESC and echocardiographic parameters, Pearson's correlation analysis was performed. Additionally, logistic regression analysis was used to determine the association between LV diastolic function and ESC. A receiver operating characteristic (ROC) curve was constructed to evaluate the performance of sudomotor function indicators in detecting impaired cardiac diastolic function. There were 301 persons (43.06%) in the NSF group, 232 (33.19%) in the MDF group, and 166 (23.75%) in the SDF group. Compared to the NSF group, the MDF and SDF groups had higher A and E/e' and lower e' values (all p < 0.05). Pearson's correlation analysis showed that A and E/e' were negatively associated with foot ESC (FESC) and hand ESC (HESC), whereas e' was positively associated with FESC and HESC (all p < 0.05). After adjusting for confounding factors, binary logistic regression analysis showed that ESC was independently associated with impaired LV diastolic function (p = 0.003). The area under the ROC curve values for FESC and HESC were 0.621 and 0.635, respectively (both p < 0.05). Deteriorating sudomotor function was associated with reduced diastolic function indicators. ESC can be used as a biomarker for detecting LV diastolic impairment.

Relation of genetic polymorphisms in microRNAs with diastolic and systolic function in type 2 diabetes mellitus

Background and aimsType 2 diabetes mellitus (T2DM) has high risk of developing cardiac dysfunction, increasing of either cardiovascular death or hospitalization for heart failure. MicroRNAs (miRNA) affect cardiac function of T2DM. The aim of this study was to investigate the relationships between five miRNA single nucleotide polymorphisms (SNP) and diastolic and systolic function of T2DM. Methods and resultsThree hundred untreated T2DM subjects were included. Each subject underwent SNP genotyping, conventional echocardiography, tissue doppler imaging, and speckle tracking imaging. The effects of miRNA SNPs on diastolic and systolic function were evaluated. The diastolic function of T2DM subjects with miR-133a-1-rs8089787 wild genotype or let-7f-rs10877887 variant genotype was lower than those with miR-133a-1-rs8089787 variant genotype or let-7f-rs10877887 wild genotype, manifesting as higher left atrial volume index, lower mean E′, and higher E/E’ (P < 0.05). There were no significant effects of miR-133a-2-rs13040413, let-7a-1-rs13293512 and miR-27a-rs895819 on the diastolic function of T2DM subjects (P > 0.05). These five miRNA SNPs had no effect on the systolic function of T2DM subjects (P > 0.05). ConclusionsMiRNA-133a-1-rs8089787 and let-7f-rs10877887 were associated with impaired cardiac diastolic function in T2DM. The findings may be a promising therapeutic targets for preventing diastolic dysfunction in T2DM.

426-P: Sudomotor Dysfunction Is Associated with Decreased Cardiac Diastolic Function in Patients with Type 2 Diabetes

Diabetic autonomic neuropathy has been proved to be associated with onset of heart failure in patients with diabetes. However, relationship between sudomotor dysfunction, the early manifestation of autonomic neuropathy, and cardiac diastolic function has not yet been investigated. This study aimed to explore the association between sudomotor function and cardiac diastolic function in patients with type 2 diabetes mellitus (T2DM). A total of 63 patients (65% male, 50±13 years old) with T2DM were enrolled and divided into two groups according to mean feet electrochemical skin conductance (ESC) assessed by sudoscan device: sudomotor dysfunction group(SDF group: ESC≤60 μS) and normal sudomotor function group (NSF group: ESC&amp;gt;60 μS). Impaired cardiac diastolic function detected by tissue Doppler imaging echocardiography manifested as elevations of late atrial (A) transmitral peak flow velocity (LgA) and the early (E) transmitral peak flow velocity/early diastolic velocity (e’) (E/e’ratio). The prevalence of sudomotor dysfunction was 30.2%. In SDF group, LgA and E/e’ ratio were significantly higher than those in NSF group (-0.2±0.2 m/s vs. -0.4±0.3 m/s, P=0.011 and 11.0±3.8 vs. 8.8±2.7, P=0.013, respectively). Pearson correlation analysis revealed that LgA was negatively correlated with mean feet ESC(r=-0.3, P=0.017). In logistic regression analyse, LgA (OR=0.05, 95%CI 0.004-0.585, P=0.017) and E/e‘ ratio (OR=0.79, 95%CI 0.641-0.970, P=0.025) were found to be independently associated with presence of sudomotor dysfunction. Cardiac diastolic function significantly decreased in type 2 diabetic patients with sudomotor dysfunction. Disclosure X. Chen: None. X. Yang: None. W. Xu: None. H. Deng: None. J. Wu: None. J. Yan: None. B. Yao: None. Funding Natural Science Foundation of Guangdong Province (2018A030313915); Medical Scientific Research Foundation of Guangdong Province (A2018286)

The correlation between maternal age, parity, cardiac diastolic function and occurrence rate of pre-eclampsia

To evaluate the effect of age and parity on maternal cardiac diastolic function in second trimester among pregnant women with normal left ventricular ejection fraction. To analyze the correlation between impaired diastolic function and pre-eclampsia. It had been suggested that maternal cardiac adaptations during pregnancy differed between nulliparous and primiparous women and also varied according to age. Impaired cardiac function may precede pre-eclampsia. Therefore, we examined the effects of parity and age on cardiac diastolic function during pregnancy and whether impaired diastolic function during the second trimester correlates with pre-eclampsia. Women with singleton pregnancies at 13 + 0 to 27 + 6 weeks’ gestation and left ventricular ejection fraction (LVEF) ≥ 50% were retrospectively identified. Diastolic function parameters were assessed using transthoracic echocardiography. Pre-eclampsia was identified from medical records. The effect of age and parity on maternal cardiac diastolic function as well as the correlation between impaired diastolic function and occurrence rate of pre-eclampsia were examined. 376 pregnant women were included (median age: 30 years; median gestational age: 14 weeks; 171 primiparous women). LVEF was 66%. Impaired cardiac diastolic function was seen in 7.8% of pregnant women < 35 years compared with 28.6% of those ≥ 35 years (p = 0.000). ROC curve showed women with maternal age over 32 began to have a higher rate of impaired cardiac diastolic function (AUC = 0.704, p = 0.000, sensitivity = 54.5%, specificity = 75.3%). There was no difference in diastolic function indices between maternal women grouped by parity. Higher maternal age was an independent risk factor of declining Em (p < 0.05). Em < 13 cm/s was significantly associated with pre-eclampsia occurrence (HR 8.56; 95% CI 3.40–21.57) after being adjusted for confounders. Maternal age is an independent risk factor for diastolic function decline. There is no difference in cardiac diastolic function between nulliparous women and primiparous women. Pre-eclampsia occurrence is significantly higher in patients with impaired diastolic function at mid-gestation. The application of risk grading using diastolic function at mid-gestation may improve the survival outcomes of pregnant women.

Ketogenic Diet Suppressed T‐Regulatory Cells and Promoted Cardiac Fibrosis via Reducing Mitochondria‐Associated Membranes and Inhibiting Mitochondrial Function

Ketogenic diet (KD) is popular in diabetic patients but its cardiac safety and efficiency on the heart are unknown. The aim of the present study is to determine the effects and the underlined mechanisms of KD on cardiac function in diabetic cardiomyopathy (DCM). We used db/db mice to model DCM, and different diets (regular or KD) were used. Cardiac function and interstitial fibrosis were determined. T-regulatory cell (Treg) number and functions were evaluated. The effects of ketone body (KB) on fatty acid (FA) and glucose metabolism, mitochondria-associated endoplasmic reticulum membranes (MAMs), and mitochondrial respiration were assessed. The mechanisms via which KB regulated MAMs and Tregs were addressed. KD improved metabolic indices in db/db mice. However, KD impaired cardiac diastolic function and exacerbated ventricular fibrosis. Proportions of circulatory CD4+CD25+Foxp3+ cells in whole blood cells and serum levels of IL-4 and IL-10 were reduced in mice fed with KD. KB suppressed the differentiation to Tregs from naive CD4+ T cells. Cultured medium from KB-treated Tregs synergically activated cardiac fibroblasts. Meanwhile, KB inhibited Treg proliferation and productions of IL-4 and IL-10. Treg MAMs, mitochondrial respiration and respiratory complexes, and FA synthesis and oxidation were all suppressed by KB while glycolytic levels were increased. L-carnitine reversed Treg proliferation and function inhibited by KB. Proportions of ST2L+ cells in Tregs were reduced by KB, as well as the production of ST2L ligand, IL-33. Reinforcement expressions of ST2L in Tregs counteracted the reductions in MAMs, mitochondrial respiration, and Treg proliferations and productions of Treg cytokines IL-4 and IL-10. Therefore, despite the improvement of metabolic indices, KD impaired Treg expansion and function and promoted cardiac fibroblast activation and interstitial fibrosis. This could be mainly mediated by the suppression of MAMs and fatty acid metabolism inhibition via blunting IL-33/ST2L signaling.

Effect of age and parity on maternal diastolic function in middle trimester pregnant women with normal left ventricular ejection fraction and potential link of diastolic function to pre-eclampsia

Abstract Background It has been suggested that maternal cardiac adaptations during pregnancy differ between nulliparous and multipara women and also vary according to the age. Impaired cardiac function precedes pre-eclampsia. Purpose To evaluate effect of age and parity on maternal cardiac diastolic function in middle trimester among pregnant women with normal left ventricular ejection fraction as well as correlation between impaired diastolic function and pre-eclampsia. Methods Pregnant women with singleton pregnancies carried from 13 weeks to 20 weeks and left ventricular ejection fraction (LVEF) ≥50% were identified. Diastolic function parameters were assessed using transthoracic echocardiography. Pre-eclampsia was identified from medical records. Results 376 pregnant women were included (median age: 30 years; median gestational age: 14 weeks; 171 multiparous women). LVEF was 66%. Impaired cardiac diastolic function was seen in 7.8% of pregnant women &amp;lt;35 years compared with 28.6% of those ≥35 years (p=0.000). ROC curve showed women with maternal age over 32 began to have a higher rate of impaired cardiac diastolic function (AUC=0.704, p=0.000, sensitivity=54.5%, specificity=75.3%). There was no difference in diastolic function indices between maternal women grouped by parity. After adjustment for confounders, maternal age can be independent effect factor of Em declined (P&amp;lt;0.05). Em&amp;lt;13cm/s was significantly associated with pre-eclampsia occurrence (HR 8.56; 95% CI: 3.40–21.57) after adjusting for the confounders. Conclusion Maternal age is an independent impact factor for diastolic function decline. There is no difference in cardiac diastolic function between nullipara and multipara. Pre-eclampsia occurrence is significantly higher in patients with diastolic function decline at mid-gestation. The utility of risk stratification using diastolic function at mid-gestation may improve the survival outcomes of pregnant women. Association between Em and PE risk Funding Acknowledgement Type of funding source: None

Fibroblast growth factor-23 is associated with imaging markers of diabetic cardiomyopathy and anti-diabetic therapeutics

BackgroundThe biomarker fibroblast growth factor-23 (FGF-23) has been associated with increased cardiovascular morbidity and mortality in both patients with and without type 2 diabetes. The aim of this study was to evaluate the relationship between FGF-23 and cardiac structure, function and perfusion in patients with type 2 diabetes and normal or mildly impaired kidney function. Furthermore, to investigate the association between FGF-23, anti-diabetes therapy and the classic complications and risk factors associated with type 2 diabetes.MethodsIn this cross-sectional study, 246 patients with type 2 diabetes underwent echocardiography and advanced cardiac magnetic resonance imaging to assess left ventricular (LV) structure and function. In addition, myocardial blood flow (MBF) during rest and pharmacological stress (adenosine 140 µg/kg/min) were evaluated in 183 of the patients. Patients with eGFR < 60 ml/min/1.73 m2 were excluded.ResultsMedian (Q1–Q3) FGF-23 was 74 (58–91) ng/L. Patients with FGF-23 above the median had lower MBF during stress (2.3 ± 0.9 vs. 2.7 ± 0.9 ml/min/g, P = 0.001) and lower overall myocardial perfusion reserve (MPR) (2.7 ± 0.8 vs. 3.3 ± 1.1, P < 0.001). LV mass (143 ± 40 vs. 138 ± 36 g, P = 0.04) and E/e* (8.5 ± 3.2 vs. 7.6 ± 2.7, P = 0.04) were higher in patients with FGF-23 above the median. In a linear model adjusted for age, sex, eGFR and hypertension, increasing FGF-23 was associated with decreased MPR (P < 0.01, R2 = 0.11) and increased E/e* (P < 0.01, R2 = 0.07). FGF-23 was lower in patients receiving glucagon like peptide-1 (GLP-1) analogues (71 (57–86) vs. 80 (60–98) ng/L, P = 0.01) than in those who did not receive GLP-1 analogues.ConclusionsIn patients with type 2 diabetes and normal or mildly impaired kidney function, increased levels of FGF-23 are associated with impaired cardiac diastolic function and decreased MPR, caused by a decrease in maximal MBF during stress. Use of GLP-1 analogues is associated with decreased levels of FGF-23.Clinical trial registrationhttps://www.clinicaltrials.gov. Unique identifier: NCT02684331. Date of registration: February 18, 2016

Abstract P2011: Chronic Systemic Administration of Pro-Inflammatory Cytokines Causes Cardiovascular Dysfunction and Downregulates Brain Expression of Regulator of G-Protein Signaling-10 in Rats

Systemic pro-inflammatory cytokines (PICs) promote central oxidative stress and neuroinflammation that contribute to sympathetic excitation and cardiovascular dysfunction in hypertension and heart failure. However, the key molecular regulators of neuroinflammatory responses in the brain remain unclear. Regulator of G-protein Signaling-10 (RGS10), a GTPase-accelerating protein that is expressed predominantly in the brain, has recently emerged as an important counter regulator of PICs-induced downstream signaling in the central nervous system. RGS10 negatively regulates NF-kB-mediated inflammatory responses in microglia and antagonizes neurotoxic effects of peripheral inflammation. The present study examined whether peripherally administered PICs alter RGS10 expression in cardiovascular/autonomic brain regions like subfornical organ (SFO) and hypothalamic paraventricular nucleus (PVN). Male SD rats received a 2-week subcutaneous infusion of vehicle, interleukin (IL)-1β (400 ng/day) and tumor necrosis factor (TNF)-α (600 ng/day). Rats treated with IL-1β (n=6) or TNF-α (n=6) had significantly (*P&lt;0.05) reduced mRNA level (fold change) of RGS10 in SFO (0.60±0.15* or 0.69±0.16* vs 1.03±0.28; IL-1β or TNF-α, vs vehicle treatment) and PVN (0.72±0.15* or 0.71±0.19* vs 1.02±0.24), and lessoned mRNA level of NF-kB inhibitor IkB-α (SFO: 0.60±0.21* or 0.55±0.16* vs 1.07±0.46; PVN: 0.70±0.31* or 0.82±0.16* vs 1.00±0.07). Treatments with IL-1β or TNF-α increased mRNA level of NADPH oxidase 2 (SFO: 1.96±0.91* or 1.62±0.47* vs 1.03±0.28; PVN: 2.00±0.82* or 1.74±0.70* vs 1.00±0.15) and cyclooxygenase-2 (SFO: 1.78±0.76* or 1.98±1.04* vs 1.00±0.13; PVN: 1.68±0.34* or 1.62±0.57* vs 1.02±0.24). Rats treated with IL-1β or TNF-α had elevated mean blood pressure (98±11* or 100±9* vs 84±5 mmHg) and increased sympathetic activity as indicated by pressure response to ganglionic blockade (38±7 * or 36±6* vs 28±4 mmHg). Additionally, IL-1β or TNF-α-treated rats had increased cardiac fibrotic markers and impaired cardiac diastolic function. These results suggest that circulating PICs reduce RGS10 expression in the brain, which may contribute to sympathetic excitation and cardiovascular dysfunction in inflammatory conditions.

Protective effects of glucagon-like peptide-1 on cardiac remodeling by inhibiting oxidative stress through mammalian target of rapamycin complex1/p70 ribosomal proteinS6 kinase pathway in diabetes mellitus.

Aims/IntroductionAlthough increased reactive oxygen species (ROS) generation is a major mechanism leading to cardiac remodeling in diabetes mellitus, research into the effects of anti‐oxidation on diabetic cardiac remodeling remains scarce and controversial. Glucagon‐like peptide‐1 (GLP‐1) shows potential anti‐oxidative effects besides lowering blood glucose. The objective of this research was to investigate the effects of GLP‐1 on cardiac remodeling and the molecular mechanism involved in diabetes mellitus.Materials and MethodsStreptozotocin‐induced diabetic rats received exenatide treatment for 3 months. Cardiac function, cardiac weight index and myocardial interstitial fibrosis were measured. Cardiomyocytes were cultured in high‐glucose medium with GLP‐1 treatment. The ROS production, apoptosis and the levels of mammalian target of rapamycin complex 1/p70 ribosomal protein S6 kinase protein expression in cardiomyocytes were analyzed.ResultsExperimental diabetes mellitus showed impaired cardiac diastolic function, increased brain natriuretic peptide expression and increased interstitial collagen deposition in the myocardium, which were ameliorated by exenatide treatment. Exenatide reduced myocardial ROS production and apoptosis in diabetes mellitus. Also, high glucose‐induced ROS generation and apoptosis in cardiomyocytes were inhibited by GLP‐1, as well as the levels of mammalian target of rapamycin complex 1/p70 ribosomal protein S6 kinase phosphorylation. Furthermore, GLP‐1 treatment upregulated adenosine monophosphate‐activated protein kinase activity in high‐glucose‐induced cardiomyocyte.ConclusionsGlucagon‐like peptide‐1 protects the cardiomyocytes from oxidative stress and apoptosis in diabetes mellitus, which might contribute to the improvement of cardiac remodeling. The cardiac protection of GLP‐1 might be dependent on inhibition of mammalian target of rapamycin complex 1/p70 ribosomal protein S6 kinase, through an adenosine monophosphate‐activated protein kinase‐mediated pathway.

Sex-specific effects of advanced maternal age on cardiovascular function in aged adult rat offspring.

Pregnancy at an advanced maternal age has an increased risk of complications for both the mothers and their offspring. We have previously shown that advanced maternal age in a rat model leads to poor fetal outcomes, maternal vascular dysfunction, and hypertension, concordant with findings in humans. Moreover, offspring from aged dams had sex-specific cardiovascular dysfunction in young adulthood. However, the detrimental impact of aging on the cardiovascular system of the offspring in this model is unknown. We hypothesized that offspring born to aged dams (9.5-10 mo old) would have impaired cardiovascular function at 12 mo of age. Echocardiographic data revealed signs of mild left ventricular diastolic dysfunction in only male offspring from aged dams [isovolumetric relaxation time: 34.27 ± 2.04 in the young dam group vs. 27.61 ± 0.99 ms in the aged dam group, P < 0.01; mitral annular velocity ratio ( E'/ A'): 1.08 ± 0.04 in the young dam group vs. 0.96 ± 0.02 in the aged dam group, P < 0.05]. We have previously shown that in young adulthood (4 mo of age), male, but not female, offspring born to aged dams had impaired recovery from ischemia-reperfusion injury. Aging did not alter the susceptibility of female offspring to ischemia-reperfusion injury. Interestingly, wire myography data revealed that male offspring from aged dams had enhanced vascular sensitivity to methacholine (negative log of EC50: 7.4 ± 0.08 in young dams vs. 7.9 ± 0.11 in aged dams, P = 0.007) due, in part, to increased prostaglandin-mediated vasodilation. Despite intact endothelium-dependent relaxation, female offspring from aged dams had elevated systolic blood pressure (125.3 ± 4.2 mmHg in young dams vs. 144.0 ± 6.9 mmHg in aged dams, P = 0.03). These data highlight sex-specific mechanisms underlying cardiovascular programming in offspring born to dams of advanced age. NEW & NOTEWORTHY Our study demonstrated that adult male and female offspring (12 mo old) born to aged dams had impaired cardiac diastolic function and increased blood pressure, respectively, signifying sex-specific differential cardiovascular effects of advanced maternal age.

Constrictive pericarditis: retrospective study of 109 patients

Background Chronic constrictive pericarditis is the most common diastolic disorder of the heart. Non-elasticity of the pericardium with impaired cardiac diastolic function is constriction. Chronic constrictive pericarditis is the result of scarring and fibrosis in mid and late diastole. The clinical presentation is similar to that of right heart failure. Historically, the etiology is helpful but not diagnostic. Echocardiography and a hemodynamic study are the main diagnostic tools. A thick pericardium of more than 4 mm is not necessarily constrictive, but thickness ≥7 mm is highly specific for constrictive features. Pericardiectomy is usually associated with early normalization of hemodynamics, which can be achieved via a mid-sternotomy or left anterolateral thoracotomy. Methods Data of 109 patients who underwent pericardiectomy from January 1987 to June 2016 were reviewed retrospectively. Results The outcome of our 109 cases consisted of mortality in 2 patients only. Conclusion Progressive, fibrotic, thickened, adherent inflammatory changes in response to various pathologies of the pericardium impairing diastolic filling can be treated by pericardiectomy. Pericardiectomy can be achieved by a mid-sternotomy or anterolateral thoracotomy without any difference in outcome. The initial hemodynamic and clinical result may not always be dramatic but continued improvement is definite because of progressive enlargement of left ventricular dimensions.

Left Atrial Volume and Pulmonary Artery Diameter Are Noninvasive Measures of Age-Related Diastolic Dysfunction in Mice.

Impaired cardiac diastolic function occurs with aging in many species and may be difficult to measure noninvasively. In humans, left atrial (LA) volume is a robust measure of chronic diastolic function as the LA is exposed to increased left ventricular filling pressures. We hypothesized that LA volume would be a useful indicator of diastolic function in aging mice. Further, we asked whether pressures were propagated backwards affecting pulmonary arteries (PAs) and right ventricle (RV). We measured LA, PA, and RV infundibulum dimensions with echocardiography and used mouse-specific Doppler systems and pressure catheters for noninvasive and invasive measures. As C57BL/6 mice aged from 3 to 29-31 months, LA volume almost tripled. LA volume increases correlated with traditional diastolic function measures. Within groups of 14- and 31-month-old mice, LA volume correlated with diastolic function measured invasively. In serial studies, mice evaluated at 20 and 24 months showed monotonic increases in LA volume; other parameters changed less predictably. PA diameters, larger in 30-month-old mice than 6-month-old mice, correlated with LA volumes. Noninvasive LA volume and PA diameter assessments are useful and state independent measures of diastolic function in mice, correlating with other measures of diastolic dysfunction in aging. Furthermore, serial measurements over 4 months demonstrated consistent increases in LA volume suitable for longitudinal cardiac aging studies.

Treatment of insulin resistance‐related cardiac and coronary dysfunction by mineralocorticoid receptor antagonism (LB671)

Cardiovascular disease is a major cause of mortality in patients with insulin resistance, a condition associated with renin‐angiotensin‐aldosterone system activation. Mineralocorticoid receptor (MR) antagonists reduce mortality in various populations but the cardiovascular benefit of these agents in insulin resistance remains unclear. We hypothesized that MR antagonism with low dose spironolactone (LSp) would treat cardiac and coronary microvascular dysfunction in insulin resistant obese Zucker (ZO) rats. Obesity, insulin resistance, hyperlipidemia, and blood pressure in ZO rats were not affected by LSp; however, circulating and adipose tissue markers of inflammation were reduced by LSp to levels similar to lean Zucker controls. Impaired cardiac diastolic function, assessed by echocardiography, was corrected by LSp in ZO rats and was associated with reduced cardiac fibrosis and oxidative stress. Similarly, impaired coronary arteriolar vasodilation to acetylcholine and insulin in ZO rats was corrected by LSp involving improved insulin‐mediated Akt phosphorylation. Interestingly, ZO rats exhibited marked immune activation involving decreased presence of Foxp3 gene expression (marker of anti‐inflammatory T regulatory cells) in cardiac tissue which was increased by LSp treatment. These results demonstrate that mineralocorticoid receptor antagonism treats insulin resistance‐associated cardiac diastolic and coronary dysfunction and that these benefits may involve modulation of the immune system.Grant Funding Source: Supported by grants from NIH (HL73101, HL107910) and VA (Merit 0018 and CDA‐2‐2030)

Duration of Migraine Is Associated with Cardiac Diastolic Dysfunction

Migraine is a common type of headache accompanied or preceded by signs of central and autonomic nervous system dysfunction. Autonomic dysfunction has been suggested to be a potential contributor to impaired cardiac diastolic function. Cardiac diastolic dysfunction is characterized by normal left ventricular contractility but impaired ventricular relaxation. It is a growing clinical entity implicated in morbidity and mortality due to heart failure. The aim of this study was to determine if any relationship exists between migraine and diastolic dysfunction. Migraineurs (N = 55), and age- and sex-matched healthy controls (N = 52) were evaluated by conventional and tissue Doppler echocardiography. Migraine-related disability in the previous 3 months was assessed by the Migraine Disability Assessment questionnaire. Baseline characteristics were recorded, and blood samples were collected. The groups did not differ in terms of sex or age. The migraine group had higher lipid levels compared with the control group. Diastolic dysfunction was significantly higher among the 30 migraineurs with a history of migraine of 10 years or more compared with the 25 migraineurs with a history of less than 10 years, (P = 0.003). In logistic regression analysis, migraine duration was shown to be an independent predictor of diastolic dysfunction (odds ratio 1.130, 95% confidence interval, P = 0.044). Cardiac diastolic dysfunction is associated with migraine. A long history of migraine is an independent predictor of diastolic dysfunction.

Exercise training ameliorates age‐related diastolic dysfunction: the role of coronary microvascular function

The risk for diastolic heart failure increases with advancing age. Regular physical exercise has been shown to prevent and/or ameliorate the progression of age‐related diastolic dysfunction; however, the underlying mechanisms have not been identified. We tested the hypothesis that adaptations of coronary microvascular function contribute to age‐ and exercise‐related changes in cardiac diastolic dysfunction. Young and old Fischer 344 male rats were randomly assigned into either a sedentary control group or an exercise‐trained group. Doppler analysis was used to evaluate ventricular diastolic function. Coronary arterioles were isolated from the left ventricular free wall to assess arteriolar contractile function. Vascular smooth muscle (VSM) proliferation was assessed by measuring wall:lumen ratio and by analysis of phosphohistone H3. Doppler analysis showed that age impaired cardiac diastolic function and late‐life exercise training improved diastolic function. Age impaired contractile function and induced localized VSM proliferation in coronary resistance arterioles. Exercise training reversed age‐related contractile dysfunction of coronary resistance arterioles and attenuated VSM cell proliferation. Our findings suggest that age and exercise affect cardiac function, in part, through alterations of VSM function of coronary resistance arterioles.

Constitutive SIRT1 overexpression impairs mitochondria and reduces cardiac function in mice

Heart failure is associated with a change in cardiac energy metabolism. SIRT1 is a NAD+-dependent protein deacetylase, and important in the regulation of cellular energy metabolism. To examine the role of SIRT1 in cardiac energy metabolism, we created transgenic mice overexpressing SIRT1 in a cardiac-specific manner, and investigated cardiac functional reserve, energy reserve, substrate uptake, and markers of mitochondrial function. High overexpression of SIRT1 caused dilated cardiomyopathy. Moderate overexpression of SIRT1 impaired cardiac diastolic function, but did not cause heart failure. Fatty acid uptake was decreased and the number of degenerated mitochondria was increased dependent on SIRT1 gene dosage. Markers of reactive oxygen species were decreased. Changes in morphology and reactive oxygen species were associated with the reduced expression of genes related to mitochondrial function and autophagy. In addition, the respiration of isolated mitochondria was decreased. Cardiac function was normal in transgenic mice expressing a low level of SIRT1 at baseline, but the mice developed cardiac dysfunction upon pressure overload. In summary, the constitutive overexpression of SIRT1 reduced cardiac function associated with impaired mitochondria in mice.

Assessment of left ventricular regional function in affected and carrier dogs with duchenne muscular dystrophy using speckle tracking echocardiography

BackgroundTwo-dimensional speckle tracking echocardiography (STE) is a relatively new method to detect regional myocardial dysfunction. To assess left ventricular (LV) regional myocardial dysfunction using STE in Duchenne muscular dystrophy model dogs (CXMDJ) without overt clinical signs of heart failure.MethodsSix affected dogs, 8 carrier dogs with CXMDJ, and 8 control dogs were used. Conventional echocardiography, systolic and diastolic function by Doppler echocardiography, tissue Doppler imaging (TDI), and strain indices using STE, were assessed and compared among the 3 groups.ResultsSignificant differences were seen in body weight, transmitral E wave and E' wave derived from TDI among the 3 groups. Although no significant difference was observed in any global strain indices, in segmental analysis, the peak radial strain rate during early diastole in posterior segment at chordae the tendineae level showed significant differences among the 3 groups.ConclusionsThe myocardial strain rate by STE served to detect the impaired cardiac diastolic function in CXMDJ without any obvious LV dilation or clinical signs. The radial strain rate may be a useful parameter to detect early myocardial impairment in CXMDJ.