Search for: All records

Abstract This study presents the development and morphology analysis of bioinspired 3D cardiovascular tissue models cultured within a dynamic capillary circuit microfluidic device. This study is significant because our in vitro 3D cardiovascular tissue models retained within a capillary circuit microfluidic device provide a less expensive, more controlled, and reproducible platform for more physiologically-relevant evaluation of cellular response to microenvironmental stimuli. The overall aim of our study is to demonstrate our cardiovascular tissue model (CTM) and vascular tissue model (VTM) actively changed their cellular morphology and exhibited structural reorganization in response to biophysical stimuli provided by microposts within the device tissue culture chambers during a 5-day period. The microfluidic device in this study was designed with the Young–Laplace and Navier–Stokes principles of capillary driven fluid flow and fabricated with 3D stereolithography (SLA) printing. The cardiac tissue model and vascular tissue model presented in this study were developed by encapsulating AC16 cardiomyocytes (CTM) and Human umbilical vein endothelial cells (VTM) in a fibrin hydrogel which were subsequently loaded into a capillary circuit microfluidic device. The cardiovascular tissue models were analyzed with fluorescent microscopy for morphological differences, average tube length, and cell orientation. We determined the VTM displayed capillary-like tube formation and the cells within both cardiovascular tissue models continued to elongate around microposts by day-5 which indicates the microfluidic system provided biophysical cues to guide cell structure and direction-specific organization. 

Graphical abstract [Formula: see text] 

Doxorubicin (DOX) is a highly effective anthracycline chemotherapy agent effective in treating a broad range of life-threatening malignancies but it causes cardiotoxicity in many subjects. While the mechanism of its cardiotoxic effects remains elusive, DOX-related cardiotoxicity can lead to heart failure in patients. In this study, we investigated the effects of DOX-induced cardiotoxicity on human cardiomyocytes (CMs) using a three-dimensional (3D) bioprinted cardiac spheroidal droplet based-system in comparison with the traditional two-dimensional cell (2D) culture model. The effects of DOX were alleviated with the addition of N -acetylcysteine (NAC) and Tiron. Caspase-3 activity was quantified, and reactive oxygen species (ROS) production was measured using dihydroethidium (DHE) staining. Application of varying concentrations of DOX (0.4 μM–1 μM) to CMs revealed a dose-specific response, with 1 μM concentration imposing maximum cytotoxicity and 0.22 ± 0.11% of viable cells in 3D samples versus 1.02 ± 0.28% viable cells in 2D cultures, after 5 days of culture. Moreover, a flow cytometric analysis study was conducted to study CMs proliferation in the presence of DOX and antioxidants. Our data support the use of a 3D bioprinted cardiac spheroidal droplet as a robust and high-throughput screening model for drug toxicity. In the future, this 3D spheroidal droplet model can be adopted as a human-derived tissue-engineered equivalent to address challenges in other various aspects of biomedical pre-clinical research. 

The use of microfluidic tissue-on-a-chip devices in conjunction with electrophysiology (EPHYS) techniques has become prominent in recent years to study cell-cell interactions critical to the understanding of cellular function in extreme environments, including spaceflight and microgravity. Current techniques are confined to invasive whole-cell recording at intermittent time points during spaceflight, limiting data acquisition and overall reduced insight on cell behaviour. Currently, there exists no validated technology that offers continuous EPHYS recording and monitoring in physiological systems exposed to microgravity. In collaboration with imec and SpaceTango, we have developed an enclosed, automated research platform that enables continuous monitoring of electrically active human cell cultures during spaceflight. The Neuropixels probe system (imec) will be integrated for the first time within an engineered in-vitro neuronal tissue-on-a-chip model that facilitates the EPHYS recording of cells in response to extracellular electrical activity in the assembled neuronal tissue platform. Our goal is to study the EPHYS recordings and understand how exposure to microgravity affects cellular interaction within human tissue-on-a-chip systems in comparison to systems maintained under Earth’s gravity. Results may be useful for dissecting the complexity of signals obtained from other tissue systems, such as cardiac or gastrointestinal, when exposed to microgravity. This study will yield valuable knowledge regarding physiological changes in human tissue-on-a-chip models due to spaceflight, as well as validate the use of this type of platform for more advanced research critical in potential human endeavours to space. 

Introduction: Myocardial fibrosis and dysfunction is one of the major cardiac complications of long-term diabetes. Prolonged hyperglycemia is known to induce myocardial dysfunction often leading up to heart failure. Hypothesis: The objective of this study was to investigate the cardioprotective effect of glycyrrhizin (GLC) on myocardial damage in engineered in-vitro human cardiac tissues. Engineered 3D tissue chips present an ideal microenvironment via therapeutically relevant interfaces to study molecular- and cellular-level events and mimic human-specific disease states, and identify new therapeutic targets in vitro. Methods: AC16 human cardiomyocyte cells were used to 3D bioprint cardiac tissue chips based on prior published work. In our study, the 3D bioprinted cardiac tissue chips (CTC) were cultured using normo- (5mM) and hyper-glycemic (25mM) conditions for up to 48 hrs. For the GLC treatment group, a subset of CTC cultured using hyperglycemic conditions were treated with 50 mM of GLC for 24 hours. Results: CTC cultured under hyperglycemic conditions demonstrated altered levels of connexin-43 (CX43) and Troponin-I implying cardiomyocyte injury. Exposure to hyperglycemia revealed changes in epigenetic markers: histone methylation marker (H3K9me)-1, Sirtuin-1, and Histone Deacetylase (HDAC)-2 as well as in inflammatory and stress related mediators such as heat shock protein (HSP)-60, receptor for advanced glycation end products (RAGE), toll like receptor (TLR)-4, high mobility group box (HMGB)-1 and CXC chemokine receptor (CXCR)-4. CTC exposed to 25mM glucose for 24 hours resulted in the downregulation of HSP60 and Sirtuin-1. Prolonged exposure to hyperglycemia led to decrease in the expression of CX43 and CXCR4; thereby adversely affecting cardiomyocyte function. Upregulated expression of DNA-binding nuclear protein HMGB1 along with changes in H3K9me1 indicated long-term hyperglycemia-induced damage to cardiomyocytes. GLC treated CTC exhibited a decrease in the expression of RAGE, TLR4 and also demonstrated altered expression of CX43, CXCR4, and troponin I. Conclusions: This study suggests that GLC possesses cardioprotective effects in human cardiomyocytes exposed to prolonged hyperglycemia.