Multimodal Imaging Reveals that Sustained Inhibition of HIF-Prolyl Hydroxylases Induces Opposing Effects on Right and Left Ventricular Function in Healthy Rats

PURPOSE

Hypoxia-inducible factor (HIF) drives transcription of critical hypoxia response genes, increasing the production of red blood cells in low oxygen conditions. In the absence of hypoxia, HIF is degraded by prolyl hydroxylases (HIF-PHs). Pharmacological HIF-PH inhibition stabilizes HIF and is being studied as a treatment for anemia. However, like sustained hypoxia, HIF-PH inhibition may increase pulmonary arterial pressure leading to right ventricular hypertrophy. The aim of this study was to assess the cardiac effects of sustained pharmacological HIF-PH inhibition using multimodal imaging, blood analysis, and histology.

METHODS

Rats were dosed daily with a pan HIF-PH inhibitor or vehicle for 4 weeks followed by a 2-week washout period and underwent longitudinal magnetic resonance imaging (MRI) and echocardiography to simultaneously assess RV and LV function. Blood samples from weeks four and six were analyzed to determine red blood cell composition. Histology was performed on the cardiac tissue from a subset of rats at weeks four and six to assess structural effects.

RESULTS

Imaging revealed that RV ejection fraction was reduced in animals receiving HIF-PH inhibitor and resulted in RV hypertrophy. Interestingly, HIF-PH inhibition had the opposite effect on the left ventricle (LV), increasing contractility measured by LV ejection fraction. LV effects were reversed by week six, while RV effects (functional and structural) were sustained.

CONCLUSION

These opposing cardiac effects of HIF-PH inhibition warrant further study to both understand the potential negative effects on RV structure and function and investigate the therapeutic potential of increased LV contractility for conditions like heart failure.

Effect of ovariohysterectomy on queen myocardial function: echocardiographic evidence

Ovariohysterectomy (OHE) is one of the most common surgeries in veterinary medicine. Although this surgical method has several advantages, it can alter the function of various organs such as heart. The present study investigated the effect of OHE on cardiac functions using M-mode echocardiography. A total of 10 healthy adult domestic short-haired cats were enrolled in the current study. Fractional shortening (FS) and ejection fraction (EF) percentages along with cardiac output (CO) were measured through the right parasternal approach in papillary muscle level view. Moreover, the levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured by enzyme-linked immunosorbent assay before OHE (D0) as well as 10 (D10), 20 (D20) and 30 (D30) days after OHE. The results of this study showed that the mean FS and EF decreased on all days of the study. The FS reduction was significant between D10 and D30 and EF changes were significant between D10 and D20. The means of CO increased significantly on D0 compared to the D10. After D20, CO reduced until the end of the study. Mean concentrations of LH and FSH increased on all research days; but, the changes were significant until D20. Despite the negative effects of OHE on myocardial function, there was no significant correlation between hormonal levels and echocardiographic findings after OHE in this study.

Acyl ghrelin improves cardiac function in heart failure and increases fractional shortening in cardiomyocytes without calcium mobilization

BACKGROUND AND AIMS

Ghrelin is an endogenous appetite-stimulating peptide hormone with potential cardiovascular benefits. Effects of acylated (activated) ghrelin were assessed in patients with heart failure and reduced ejection fraction (HFrEF) and in ex vivo mouse cardiomyocytes.

METHODS AND RESULTS

In a randomized placebo-controlled double-blind trial, 31 patients with chronic HFrEF were randomized to synthetic human acyl ghrelin (0.1 µg/kg/min) or placebo intravenously over 120 min. The primary outcome was change in cardiac output (CO). Isolated mouse cardiomyocytes were treated with acyl ghrelin and fractional shortening and calcium transients were assessed. Acyl ghrelin but not placebo increased cardiac output (acyl ghrelin: 4.08 ± 1.15 to 5.23 ± 1.98 L/min; placebo: 4.26 ± 1.23 to 4.11 ± 1.99 L/min, P < 0.001). Acyl ghrelin caused a significant increase in stroke volume and nominal increases in left ventricular ejection fraction and segmental longitudinal strain and tricuspid annular plane systolic excursion. There were no effects on blood pressure, arrhythmias, or ischaemia. Heart rate decreased nominally (acyl ghrelin: 71 ± 11 to 67 ± 11  b.p.m.; placebo 69 ± 8 to 68 ± 10  b.p.m.). In cardiomyocytes, acyl ghrelin increased fractional shortening, did not affect cellular Ca2+ transients, and reduced troponin I phosphorylation. The increase in fractional shortening and reduction in troponin I phosphorylation was blocked by the acyl ghrelin antagonist D-Lys 3.

CONCLUSION

In patients with HFrEF, acyl ghrelin increased cardiac output without causing hypotension, tachycardia, arrhythmia, or ischaemia. In isolated cardiomyocytes, acyl ghrelin increased contractility independently of preload and afterload and without Ca2+ mobilization, which may explain the lack of clinical side effects. Ghrelin treatment should be explored in additional randomized trials.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05277415.

Vitamin D levels and left ventricular function in beta-thalassemia major with iron overload

Heart disease is the primary cause of death in patients with beta-thalassemia major. The study aimed to determine the association between vitamin D and left ventricular function in patients with beta-thalassemia major with iron overload. A cross-sectional hospital-based study was conducted, where the vitamin D and ferritin levels of children living with beta-thalassemia major were measured, and left ventricular function was assessed utilizing ejection fraction (EF) and fractional shortening (FS) using 2D echocardiography. The mean serum ferritin was 4622 ± 2289 ng/ml, and the mean serum vitamin D levels were 22 ± 7.7 ng/ml. The mean values of EF were 62.30 ± 6.9%, and FS was 31.21 ± 4.8%. Statistically significant negative correlation (r = -0.447, p < 0.001) was found between vitamin D and serum ferritin values, and a significant positive association was found between vitamin D levels concerning EF and FS with a p-value of 0.034 and 0.014, respectively.Conclusion: It was observed  that increasing ferritin was associated with lower vitamin D levels which in turn influenced fractional shortening /cardiac function in these patients.  What is Known: • Patients with Beta Thalassemia major on long term transfusion are prone to develop heart disease / cardiac failure due to chronic iron overload. What is New: • Patients with beta thalassemia major on long term term transfusions with iron overload who are vitamin D deficient are more prone to the cardiac complications which inturn can be prevented by vitamin D supplementation.

The effect of placental transfusion on hemodynamics in premature newborns: a randomized controlled trial

Despite of growing evidence of the beneficial effects of placental transfusion techniques, there is no available sufficient data about their effects on vulnerable hemodynamics and myocardium of premature infants. The purpose of this work is to study ventricular functions and hemodynamics after applying different placental transfusion techniques, delayed cord clamping (DCC), cut cord milking (C-UCM), and intact cord milking (I-UCM). Sixty-four infants delivered whether by C-section or vaginal delivery were randomly assigned to undergo C-UCM (20-30 cm), I-UCM (3-4 strippings), and DCC (30-60 s). Functional echocardiography was done on day 1 and day 3 of life for 57 infants. Primary outcome variable was superior vena cava flow measurement in infants having placental transfusion in the first 24 h of life and between 64 and 72 h. Secondary outcomes were other echocardiographic and clinical hemodynamic parameters, and biventricular functions in those infants. Of a total 196 preterm infants ≤ 32 weeks delivered in the study period, from January 2021 to August 2021, 57 infants were eligible and survived till the second examination. They were randomly assigned to the three groups. Neonates randomly assigned to DCC had significantly higher superior vena cava flow and lower right ventricular systolic function in the first 24 h of life. This finding vanished at day 3. Neonates undergone different methods of placental transfusions had similar hemoglobin, admission temperature, and mean blood pressure in the first 24 h of life.

CONCLUSION

Despite their potential benefits, placental transfusions have shown to alter the hemodynamics and adversely affect myocardial function of premature neonates.

TRIAL REGISTRATION

This trial was registered in the clinical trial gov NCT04811872.

WHAT IS KNOWN

• Placental transfusion techniques might have benefits regarding prematurity- related morbidities and mortality.

WHAT IS NEW

• Placental transfusion might adversely affect the myocardium and alter hemodynamics in premature infants.

Role of Anti-Beta-1-Adrenergic Receptor Antibodies in Cardiac Dysfunction in Patients with Cirrhotic Cardiomyopathy

Cirrhotic cardiomyopathy (CCM) is a recognized complication of cirrhosis and is associated with poor outcomes, especially under challenges such as surgery/liver transplantation. However, the mechanism is not clear, and the treatment is not specific. The present study aimed to evaluate the role of anti-β₁-adrenergic receptor antibodies (anti-β1-AR) in CCM. We enrolled 3 groups: healthy controls, cirrhotic patients without CCM, and patients with CCM. We found that the anti-β1-AR levels in the CCM group were significantly higher than that in the non-CCM group; anti-β1-AR was positively correlated to NT-proBNP, negatively correlated to left ventricular ejection fraction, fractional shortening ((r =  - 0.466, P < 0.05), and the ratio of peak early (E wave) and atrial (A wave) flow velocities (E/A (r =  - 0.475, P < 0.05) in CCM patients. Anti-β1-AR is a useful predictive biomarker for the presence of CCM and eventually may also have therapeutic implications. Clinical Trials Registration: Chinese Clinical Trials No. ChiCTR 2,000,037,730.

Left ventricular longitudinal wall fractional shortening accurately predicts longitudinal strain in critically ill patients with septic shock

Background

Left ventricular longitudinal strain (LVLS) may be a sensitive indicator of left ventricular (LV) systolic function in patients with sepsis, but is dependent on high image quality and analysis software. Mitral annular plane systolic excursion (MAPSE) and the novel left ventricular longitudinal wall fractional shortening (LV-LWFS) are bedside echocardiographic indicators of LV systolic function that are less dependent on image quality. Both are sparsely investigated in the critically ill population, and may potentially be used as surrogates for LVLS. We assessed if LVLS may be predicted by LV-LWFS and MAPSE in patients with septic shock. We also assessed the repeatability and inter-rater agreement of LVLS, LV-LWFS and MAPSE measurements.

Results

122 TTE studies from 3 echocardiographic data repositories of patients admitted to ICU with septic shock were retrospectively assessed, of which 73 were suitable for LVLS analysis using speckle tracking. The correlations between LVLS vs. LV-LWFS and LVLS vs. MAPSE were 0.89 (p < 0.001) and 0.81 (p < 0.001) with mean squared errors of 5.8% and 9.1%, respectively. Using the generated regression equation, LV-LWFS predicted LVLS with a high degree of accuracy and precision, with bias and limits of agreement of -0.044 ± 4.7% and mean squared prediction error of 5.8%. Interobserver repeatability was good, with high intraclass correlation coefficients (0.96–0.97), small bias and tight limits of agreement (≤ 4.1% for all analyses) between observers for all measurements.

Conclusions

LV-LWFS may be used to estimate LVLS in patients with septic shock. MAPSE also performed well, but was slightly inferior compared to LV-LWFS in estimating LVLS. Feasibility of MAPSE and LV-LWFS was excellent, as was interobserver repeatability.

Measurement of fetal automated fractional shortening using two-dimensional tracking in multiple centers

PURPOSE

To establish a normal reference range for automated fractional shortening (Auto FS) in normal singleton fetuses measured at multiple centers.

METHODS

This study was conducted from May 2017 to March 2019. It was undertaken on normal singleton fetuses. First, a four-chamber view of the fetal heart was recorded in the B-mode. Then, the region of interest was set on the edge of the ventricular septum and on the edge of the ventricular muscle at a point one-third away from the atrioventricular valve and toward the cardiac apex. Tracking was automatically performed. Values measured in the right ventricle were defined as R-Auto FS, and in the left ventricle as L-Auto FS. Furthermore, combined-Auto FS was defined as the measurement across both ventricles.

RESULTS

A total of 442 normal fetuses were assessed. R-Auto FS decreased significantly with gestational age, and L-Auto FS showed a similar tendency (Spearman's correlation analysis: r_s =  - 0.415 and r_s =  - 0.252, respectively). Combined-Auto FS showed a similar decline as the gestational age increased (r_s =  - 0.451).

CONCLUSION

In this study, we succeeded in defining a reference Auto FS value not only at one institution but also multiple centers. This study suggests that Auto FS can be used clinically and effectively.

Feasibility of automated fetal fractional shortening measurement with two-dimensional tracking and construction of a reference range for normal fetuses

PURPOSE

To assess the feasibility of an automated fractional shortening (Auto FS) measurement method using two-dimensional tracking and to construct a reference range for normal fetuses.

METHODS

This study was conducted from May 2017 to March 2018. First, cardiac motion in the four-chamber view was recorded in the B-mode. Subsequently, the region of interest was set on the edge of the ventricular septum or ventricular muscle at a point one-third away from the atrioventricular valve toward the cardiac apex. Tracking was automatically performed. Values measured between the ventricular septum and right ventricle were defined as R-Auto FS, whereas those measured between the ventricular septum and left ventricle were defined as L-Auto FS. Those on each ventricular muscle were defined as Combined-Auto FS.

RESULTS

Data were obtained from 131 singleton fetuses. R-Auto FS significantly decreased with an increase in the number of gestational weeks, and L-Auto FS and Combined-Auto FS showed the same tendency (Spearman's correlation analysis: p = - .528, p = - .351, and p = - .636, respectively).

CONCLUSION

We succeeded in defining a reference Auto FS value for normal singleton pregnancies. Auto FS was negatively correlated with gestational age. This novel technique can assess fetal heart contractility.

Oral corticosteroids and onset of cardiomyopathy in Duchenne muscular dystrophy

OBJECTIVE

To estimate the age when cardiomyopathy develops in boys with Duchenne muscular dystrophy (DMD) and to analyze the effect of corticosteroid treatment on the age of cardiomyopathy onset.

STUDY DESIGN

We identified a population-based sample of 462 boys with DMD, born between 1982 and 2005, in 5 surveillance sites in the US. Echocardiographic and corticosteroid treatment data were collected. Cardiomyopathy was defined by a reduced fractional shortening (<28%) or ejection fraction (<55%). The age of cardiomyopathy onset was determined. Survival analysis was performed to determine the effects of corticosteroid treatment on cardiomyopathy onset.

RESULTS

The mean (SD) age of cardiomyopathy onset was 14.3 (4.2) years for the entire population and 15.2 (3.4) years in corticosteroid-treated vs 13.1 (4.8) in non-treated boys. Survival analysis described a significant delay of cardiomyopathy onset for boys treated with corticosteroids (P < .02). By 14.3 years of age, 63% of non-treated boys had developed cardiomyopathy vs only 36% of those treated. Among boys treated with corticosteroids, there is a significant positive effect of duration of corticosteroid treatment on cardiomyopathy onset (P < .0001). For every year of corticosteroid treatment, the probability of developing cardiomyopathy decreased by 4%.

CONCLUSIONS

Oral corticosteroid treatment was associated with delayed cardiomyopathy onset. The duration of corticosteroid treatment also correlated positively with delayed cardiomyopathy onset. Our analysis suggests that a boy with DMD treated for 5 years with corticosteroids might experience a 20% decrease in the likelihood of developing cardiomyopathy compared with untreated boys.