Comparative analysis of hypoxic response of human microvascular and umbilical vein endothelial cells in 2D and 3D cell culture systems.

In vitro cultivation conditions play a crucial role in cell physiology and the cellular response to external stimuli. Oxygen concentrations represent an essential microenvironmental factor influencing cell physiology and behaviour both in vivo and in vitro. Therefore, new approaches are urgently needed to monitor and control oxygen concentrations in 2D and 3D cultures, as well as cell reactions to these concentrations. In this work, we modified two types of human endothelial cells-human microvascular (huMECs) and umbilical vein endothelial cells (huVECs) with genetically encoded hypoxia biosensors and monitored cell reactions in 2D to different oxygen concentrations. Moreover, we fabricated 3D cell spheroids of different cell numbers and sizes to reveal the onset of hypoxia in huVECs and huMECs. We could demonstrate a quantitative sensor response of two cell types to reduced oxygen supply in 2D and reveal different thresholds for hypoxic response. In 3D cell spheroids we could estimate critical construct sizes for the appearance of a hypoxic core. This work for the first time directly demonstrates different hypoxic signatures for huVECs and huMECs in 2D and 3D cell culture systems.

Cabergoline treatment promotes myocardial recovery in peripartum cardiomyopathy.

AIMS: Peripartum cardiomyopathy (PPCM) is a rare heart disease, occurring in previously heart-healthy women during the last month of pregnancy or the first months after delivery due to left ventricular (LV) systolic dysfunction. A common pathomechanistic pathway of PPCM includes increased oxidative stress and the subsequent generation of a cleaved prolactin fragment (16 kDa PRL), which promotes the onset of heart failure (HF) in a microRNA (miR)-146a-dependent manner. Inhibition of prolactin secretion with the dopamine D2 receptor (D2R) agonist bromocriptine combined with standard HF therapy supports cardiac recovery. This study examined whether treatment with the more selective D2R agonist cabergoline prevents HF development in an experimental PPCM mouse model and might be used as an alternative treatment regime for PPCM. METHODS AND RESULTS: Postpartum (PP) female PPCM-prone mice with a cardiomyocyte restricted STAT3-deficiency (αMHC-Cretg/+ ; Stat3fl/fl ; CKO) were treated over two consecutive nursing periods with cabergoline (CKO Cab, 0.5 mg/kg/day) and were compared with bromocriptine treated CKO (CKO Br) and postpartum-matched WT and CKO mice. Cabergoline treatment in CKO PP mice preserved cardiac function [fractional shortening (FS): CKO Cab: 34.5 ± 9.4% vs. CKO: 22.1 ± 9%, P < 0.05] and prevented the development of cardiac hypertrophy, fibrosis, and inflammation as effective as bromocriptine therapy (FS: CKO Br: 33.4 ± 5.6%). The myocardial up-regulation of the PPCM biomarkers plasminogen inhibitor activator 1 (PAI-1) and miR-146a were prevented by both cabergoline and bromocriptine therapy. A small cohort of three PPCM patients from the German PPCM Registry was treated with cabergoline (1 mg per week for 2 weeks, followed by 0.5 mg per week for another 6 weeks) due to a temporary unavailability of bromocriptine. All PPCM patients initially presented with a severely reduced LV ejection fraction (LVEF: 26 ± 2%). However, at 6 months of follow-up, LV function (LVEF: 56 ± 2%) fully recovered in all three PPCM patients, and no adverse events were detected. CONCLUSIONS: In the experimental PPCM mouse model, the selective D2R agonist cabergoline prevents the onset of postpartum HF similar to bromocriptine. In PPCM patients, cabergoline treatment was safe and effective as all patients fully recovered. Cabergoline might serve as a promising alternative to bromocriptine. However, these findings are based on experimental data and a small case series and thus have to be interpreted with caution and should be validated in a larger clinical trial.

Neuraminidases-Key Players in the Inflammatory Response after Pathophysiological Cardiac Stress and Potential New Therapeutic Targets in Cardiac Disease.

Glycoproteins and glycolipids on the cell surfaces of vertebrates and higher invertebrates contain α-keto acid sugars called sialic acids, terminally attached to their glycan structures. The actual level of sialylation, regulated through enzymatic removal of the latter ones by NEU enzymes, highly affects protein-protein, cell-matrix and cell-cell interactions. Thus, their regulatory features affect a large number of different cell types, including those of the immune system. Research regarding NEUs within heart and vessels provides new insights of their involvement in the development of cardiovascular pathologies and identifies mechanisms on how inhibiting NEU enzymes can have a beneficial effect on cardiac remodelling and on a number of different cardiac diseases including CMs and atherosclerosis. In this regard, a multitude of clinical studies demonstrated the potential of N-acetylneuraminic acid (Neu5Ac) to serve as a biomarker following cardiac diseases. Anti-influenza drugs i.e., zanamivir and oseltamivir are viral NEU inhibitors, thus, they block the enzymatic activity of NEUs. When considering the improvement in cardiac function in several different cardiac disease animal models, which results from NEU reduction, the inhibition of NEU enzymes provides a new potential therapeutic treatment strategy to treat cardiac inflammatory pathologies, and thus, administrate cardioprotection.