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  1. An organotypic heart on-a-chip modeling long QT syndrome type 2 was created to study effect of R531W mutation in LQTS2 pathology. 
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  2. Despite significant efforts in the study of cardiovascular diseases (CVDs), they persist as the leading cause of mortality worldwide. Considerable research into human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) has highlighted their immense potential in the development of in vitro human cardiac tissues for broad mechanistic, therapeutic, and patient-specific disease modeling studies in the pursuit of CVD research. However, the relatively immature state of hPSC-CMs remains an obstacle in enhancing clinical relevance ofengineered cardiac tissue models. In this study, we describe development of a microfluidic platform for 3D modeling of cardiac tissues, derived from both rat cells and hPSC-CMs, to better recapitulate the native myocardium through co-culture with interstitial cells (specifically cardiac fibroblasts), biomimetic collagen hydrogel encapsulation, and induction of highly anisotropic tissue architecture. The presented platform is precisely engineered through incorporation of surface topography in the form of staggered microposts to enable long-term culture and maturation of cardiac cells, resulting in formation of physiologically relevant cardiac tissues with anisotropy that mimics native myocardium. After two weeks of culture, hPSC-derived cardiac tissues exhibited well-defined sarcomeric striations, highly synchronous contractions, and upregulation of several maturation genes, including HCN1, KCNQ1, CAV1.2, CAV3.1, PLN, and RYR2. These findings demonstrate the ability of the proposed engineered platform to mature animal- as well as human stem cell-derived cardiac tissues over an extended period of culture, providing a novel microfluidic chip with the capability for cardiac disease modeling and therapeutic testing. 
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  3. Cardiovascular diseases, including myocardial infarction (MI), persist as the leading cause of mortality and morbidity worldwide. The limited regenerative capacity of the myocardium presents significant challenges specifically for the treatment of MI and, subsequently, heart failure (HF). Traditional therapeutic approaches mainly rely on limiting the induced damage or the stress on the remaining viable myocardium through pharmacological regulation of remodeling mechanisms, rather than replacement or regeneration of the injured tissue. The emerging alternative regenerative medicine-based approaches have focused on restoring the damaged myocardial tissue with newly engineered functional and bioinspired tissue units. Cardiac regenerative medicine approaches can be broadly categorized into three groups: cell-based therapies, scaffold-based cardiac tissue engineering, and scaffold-free cardiac tissue engineering. Despite significant advancements, however, the clinical translation of these approaches has been critically hindered by two key obstacles for successful structural and functional replacement of the damaged myocardium, namely: poor engraftment of engineered tissue into the damaged cardiac muscle and weak electromechanical coupling of transplanted cells with the native tissue. To that end, the integration of micro- and nanoscale technologies along with recent advancements in stem cell technologies have opened new avenues for engineering of structurally mature and highly functional scaffold-based (SB-CMTs) and scaffold-free cardiac microtissues (SF-CMTs) with enhanced cellular organization and electromechanical coupling for the treatment of MI and HF. In this review article, we will present the state-of-the-art approaches and recent advancements in the engineering of SF-CMTs for myocardial repair. 
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  4. Abstract

    The perivascular niche (PVN) is a glioblastoma tumor microenvironment (TME) that serves as a safe haven for glioma stem cells (GSCs), and acts as a reservoir that inevitably leads to tumor recurrence. Understanding cellular interactions in the PVN that drive GSC treatment resistance and stemness is crucial to develop lasting therapies for glioblastoma. The limitations of in vivo models and in vitro assays have led to critical knowledge gaps regarding the influence of various cell types in the PVN on GSCs behavior. This study developed an organotypic triculture microfluidic model as a means to recapitulate the PVN and study its impact on GSCs. This triculture platform, comprised of endothelial cells (ECs), astrocytes, and GSCs, is used to investigate GSC invasion, proliferation and stemness. Both ECs and astrocytes significantly increased invasiveness of GSCs. This study futher identified 15 ligand‐receptor pairs using single‐cell RNAseq with putative chemotactic mechanisms of GSCs, where the receptor is up‐regulated in GSCs and the diffusible ligand is expressed in either astrocytes or ECs. Notably, the ligand–receptor pair SAA1‐FPR1 is demonstrated to be involved in chemotactic invasion of GSCs toward PVN. The novel triculture platform presented herein can be used for therapeutic development and discovery of molecular mechanisms driving GSC biology.

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