Dataset Information

The Relationship Between Heart Rate and Left Ventricular Isovolumic Relaxation During Normoxia and Hypoxia-Asphyxia in Newborn Piglets.

ABSTRACT: Background: Many asphyxiated neonates have cardiac complications including arrhythmia and contractile dysfunction. Little is known about the relationship between heart rate (HR) and diastolic function in asphyxiated neonates. We aimed to study the relationship between HR and left ventricular (LV) isovolumic relaxation (IVR) in neonates with asphyxia using a swine model. Methods: Term newborn piglets were anesthetized and acutely instrumented with the placement of Millar^® catheter in the left ventricle. Hemodynamic parameters including HR, cardiac output, stroke volume, dP/dt_max and dP/dt_min, and IVR time constant (Tau) were continuously measured and recorded. Sixteen piglets were exposed to 50-minute normocapnic hypoxia followed by asphyxia (mean of 3.2 min) by clamping of the endotracheal tube. Sham-operated piglets (n = 11) had no hypoxia nor asphyxia. The relationship between HR and other hemodynamic parameters were analyzed using Pearson Product Moment correlation test. Results: Asphyxiated piglets had cardiogenic shock and metabolic acidosis (vs. sham-operated piglets). There were significant correlations between HR and diastolic function as shown by Tau at baseline (sham-operated: r = -0.68, p = 0.02; asphyxia: r = -0.55, p = 0.03) and during normoxia (53 min) of sham-operated piglets (r = -0.69, p = 0.02). HR and Tau was not correlated during hypoxia-asphyxia (HA) (r = -0.01, p = 0.97). Cardiac output was tightly correlated with stroke volume (p < 0.001) but not HR throughout the experimental period in both groups. There was no significant correlation between HR and other hemodynamic parameters during the experimental period in both groups. Conclusion: We observed an uncoupling between HR and IVR Tau of the neonatal heart during HA, which deserves further studies of the relationship between HR and LV diastolic function.

SUBMITTER: Shen W

PROVIDER: S-EPMC6514222 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Relationship Between Heart Rate and Left Ventricular Isovolumic Relaxation During Normoxia and Hypoxia-Asphyxia in Newborn Piglets.

Shen Wei W Xu Xin X Lee Tze-Fun TF Schmölzer Georg G Cheung Po-Yin PY

Frontiers in physiology 20190507

Background: Many asphyxiated neonates have cardiac complications including arrhythmia and contractile dysfunction. Little is known about the relationship between heart rate (HR) and diastolic function in asphyxiated neonates. We aimed to study the relationship between HR and left ventricular (LV) isovolumic relaxation (IVR) in neonates with asphyxia using a swine model. Methods: Term newborn piglets were anesthetized and acutely instrumented with the placement of Millar® ...[more]

PMID: 31133873

Similar Datasets

Project description:ObjectiveProinflammatory cytokine interleukin 17 (IL-17) is involved in ventricular remodeling, mainly of the left ventricle. This study was designed to explore the role of IL-17 played in the pathogenesis of right ventricular hypertrophy (RVH), aiming to provide a novel treatment target or diagnostic biomarker options for improving the care of RVH patients.MethodsC57BL/6 mice were maintained in 10% O2 chamber or room air for four weeks. Right ventricular hypertrophy index (RVHI), RV/body weight ratio, pulmonary arteriolar remodeling determined by percent media thickness (%MT), and the cardiomyocyte diameter of RV were evaluated. Mice were treated with exogenous recombinant mouse IL-17 (rmIL-17, 1 μg per dose twice a week) for four weeks. H9c2 cardiomyocytes were cultured and treated with IL-17 (10 ng/mL) and STAT3 inhibitor (10 ng/mL) either under normoxia (21% O2, 5% CO2, 74% N2) or under hypoxia (3% O2, 5% CO2, 92% N2). Cardiomyocyte viability was assessed by Cell counting kit 8 (CCK-8) assay. The mRNA level was detected by RT-PCR, where as the protein expression was measured by Western blot, immunohistochemistry, and immunofluorescent analyses.ResultsIn vivo experiments showed that IL-17 did not affect the pulmonary artery under normoxia, after treatment with rmIL-17, %MT was not changed, while RVHI and the RV/body weight ratio were increased, indicating that IL-17 directly induced right ventricular hypertrophy. In a time-course study, the mice were exposed to hypoxia for 0, 1, 2, 3, 4 weeks, respectively. We found that the expression of IL-17 was gradually upregulated in RV tissue in a time-dependent manner after one week of hypoxia exposure, especially at the third and fourth week. Cardiomyocyte hypertrophy and apoptosis were observed after the exposure of the mice to hypoxia for four weeks, rmIL-17 further aggravated the hypoxia-induced cardiomyocyte hypertrophy and apoptosis. The expression of p-STAT3 in the IL-17-deficient mice was lower than in the wild-type mice. In vitro, IL-17 inhibited cardiomyocyte viability and induced cardiomyocyte apoptosis via STAT3 under both normoxic and hypoxic conditions.ConclusionsThese findings support a role for IL-17 as a mediator in the pathogenesis RVH, which might be considered as a potential novel anti-inflammation therapeutic strategy or diagnostic biomarker for RVH.

Dataset Information

The Relationship Between Heart Rate and Left Ventricular Isovolumic Relaxation During Normoxia and Hypoxia-Asphyxia in Newborn Piglets.

Publications

The Relationship Between Heart Rate and Left Ventricular Isovolumic Relaxation During Normoxia and Hypoxia-Asphyxia in Newborn Piglets.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets