Abstract 16123: In Vitro Valve-on-chip Platform to Assess the Effects of Hemodynamic and Mechanical Stimuli on Early Calcific Disease Progression

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Ishita Tandon ◽  
Cody Gish ◽  
Nasya Sturdivant ◽  
Asya Ozkizilcik ◽  
Celeste Dunn ◽  
...  
Keyword(s):  
Disease Progression ◽  
Nodule Formation ◽  
Shear Stresses ◽  
Matrix Remodeling ◽  
Mechanical Stimuli ◽  
Native Valve ◽  
Hemodynamic Forces ◽  
Disease Initiation ◽  
On Chip

Introduction: Calcific aortic valve disease (CAVD) involves mechanical stress, endothelial dysfunction, matrix remodeling, and mineral deposition. Complex mechanical and hemodynamic environment around the valve closely affects its function, biology, and disease. However, the exact role of these forces in regulating cellular dysfunction during disease initiation is yet to be elucidated. Methods and Results: We developed a 3D valve-on-chip (VOC) model that encompasses cell-cell and cell-matrix interactions, flow shear stresses and cyclic strains, better mimicking the native valve. The multilayered VOC construct was built in house using photolithography and soft lithography and a silicon based polymer (Fig.1A). Valve endothelial cells (VECs) are seeded in a monolayer on a porous PDMS membrane (Fig.B) which separates the VECs from the a matrigel-collagen semi interpenetrating hybrid gel housing valve interstitial cells (VICs) (Fig.3C). We simulated either static or 20% (pathological) strain under quiescent or osteogenic conditions. Osteogenic VICs demonstrated nodule formation (Fig.1D) and had reduced redox ratios in 20% stretch conditions suggesting disease progression (Fig.1E,F). Effect of mechanical and hemodynamic forces on structure, function, and phenotypic changes in VECs and VICs particularly during disease initiation will be further assessed. Conclusions: This VOC model for VEC-VIC co-culture better mimics the native valve environment and can be used to study the early disease mechanisms. The VOC platform can be used as a drug testing tool and aid in development of treatment strategies through efficient employment in the laboratory. Further exploring the effect of mechanical and hemodynamic forces may reveal mechanosensitive signaling cascades involved in disease progression, which can be targeted for CAVD therapeutics.

scholarly journals Transcriptome comparisons of in vitro intestinal epithelia grown under static and microfluidic gut-on-chip conditions with in vivo human epithelia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kornphimol Kulthong ◽  
Guido J. E. J. Hooiveld ◽  
Loes Duivenvoorde ◽  
Ignacio Miro Estruch ◽  
Victor Marin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Culture Conditions ◽  
Gene Set Enrichment Analysis ◽  
Shear Stresses ◽  
Static Culture ◽  
Dynamic Culture ◽  
Intestinal Segments ◽  
On Chip

AbstractGut-on-chip devices enable exposure of cells to a continuous flow of culture medium, inducing shear stresses and could thus better recapitulate the in vivo human intestinal environment in an in vitro epithelial model compared to static culture methods. We aimed to study if dynamic culture conditions affect the gene expression of Caco-2 cells cultured statically or dynamically in a gut-on-chip device and how these gene expression patterns compared to that of intestinal segments in vivo. For this we applied whole genome transcriptomics. Dynamic culture conditions led to a total of 5927 differentially expressed genes (3280 upregulated and 2647 downregulated genes) compared to static culture conditions. Gene set enrichment analysis revealed upregulated pathways associated with the immune system, signal transduction and cell growth and death, and downregulated pathways associated with drug metabolism, compound digestion and absorption under dynamic culture conditions. Comparison of the in vitro gene expression data with transcriptome profiles of human in vivo duodenum, jejunum, ileum and colon tissue samples showed similarities in gene expression profiles with intestinal segments. It is concluded that both the static and the dynamic gut-on-chip model are suitable to study human intestinal epithelial responses as an alternative for animal models.

scholarly journals Luminal Flow Actuation Generates Coupled Shear and Strain in a Microvessel-on-Chip

2021 ◽  
Author(s):  
Claire A. Dessalles ◽  
Clara Ramón-Lozano ◽  
Avin Babataheri ◽  
Abdul I. Barakat
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Fluid Pressure ◽  
Shear Stresses ◽  
Collagen Hydrogel ◽  
Luminal Flow ◽  
Wall Shear ◽  
On Chip

AbstractIn the microvasculature, blood flow-derived forces are key regulators of vascular structure and function. Consequently, the development of hydrogel-based microvessel-on-chip systems that strive to mimic the in vivo cellular organization and mechanical environment has received great attention in recent years. However, despite intensive efforts, current microvessel- on-chip systems suffer from several limitations, most notably failure to produce physiologically relevant wall strain levels. In this study, a novel microvessel-on-chip based on the templating technique and using luminal flow actuation to generate physiologically relevant levels of wall shear stress and circumferential stretch is presented. Normal forces induced by the luminal pressure compress the surrounding soft collagen hydrogel, dilate the channel, and create large circumferential strain. The fluid pressure gradient in the system drives flow forward and generates realistic pulsatile wall shear stresses. Rigorous characterization of the system reveals the crucial role played by the poroelastic behavior of the hydrogel in determining the magnitudes of the wall shear stress and strain. The experimental measurements are combined with an analytical model of flow in both the lumen and the porous hydrogel to provide an exceptionally versatile user manual for an application-based choice of parameters in microvessels-on-chip. This unique strategy of flow actuation adds a dimension to the capabilities of microvessel-on-chip systems and provides a more general framework for improving hydrogel-based in vitro engineered platforms.Abstract Figure

scholarly journals Sorption of neuropsychopharmaca in microfluidic materials for in-vitro studies

2021 ◽  
Author(s):  
Thomas E Winkler ◽  
Anna Herland
Keyword(s):  
Small Molecule ◽  
Biological Fluids ◽  
Type System ◽  
Sorption Behavior ◽  
Shear Stresses ◽  
Surface Areas ◽  
Biological Studies ◽  
On Chip

Sorption (i.e., ad- & ab-sorption) of small-molecule compounds to polydimethylsiloxane (PDMS) is widely acknowledged. However, studies to date have largely been conducted under atypical conditions for microfluidic applications (lack of perfusion, lack of biological fluids); especially considering the biological studies such as Organs-on-Chips where small-molecule sorption poses the largest concern. Here, we present the first study of small-molecule sorption under relevant conditions for microphysiological systems, focusing on a standard geometry for biological barrier studies that find application in pharmacokinetics. We specifically assess the sorption of a compound panel including 15 neuropsychopharmaca at in-vivo concentration levels. We consider devices constructed from PDMS as well as two material alternatives (off-stoichiometry thiol-ene-epoxy, or tape/polycarbonate laminates). Moreover, we study the much-neglected impact of peristaltic pump tubing, an essential component of the recirculating systems required to achieve in-vivo-like perfusion shear stresses. We find that choice of device material does not significantly impact sorption behavior in our barrier-on-chip-type system. Our PDMS observations in particular suggest that excessive compound sorption observed in prior studies is not sufficiently described by compound hydrophobicity or other suggested predictors. Critically, we show that sorption by peristaltic tubing, including the commonly-utilized PharMed BPT, dominates over device sorption even on an area-normalized basis, let alone at the typically much larger tubing surface areas. Our findings highlight the importance of validating compound dosages in Organ-on-Chip studies, as well as the need for considering tubing materials with equal or higher care than device materials.

scholarly journals Hemodynamics and Mechanobiology of Aortic Valve Inflammation and Calcification

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Kartik Balachandran ◽  
Philippe Sucosky ◽  
Ajit P. Yoganathan
Keyword(s):  
Aortic Valve ◽  
Ex Vivo ◽  
Axial Stress ◽  
Biological Response ◽  
Shear Stresses ◽  
Mechanical Stimuli ◽  
Valve Remodeling ◽  
Valve Pathology ◽  
Opening And Closing

Cardiac valves function in a mechanically complex environment, opening and closing close to a billion times during the average human lifetime, experiencing transvalvular pressures and pulsatile and oscillatory shear stresses, as well as bending and axial stress. Although valves were originally thought to be passive pieces of tissue, recent evidence points to an intimate interplay between the hemodynamic environment and biological response of the valve. Several decades of study have been devoted to understanding these varied mechanical stimuli and how they might induce valve pathology. Here, we review efforts taken in understanding the valvular response to its mechanical milieu and key insights gained fromin vitroandex vivowhole-tissue studies in the mechanobiology of aortic valve remodeling, inflammation, and calcification.

scholarly journals Bio-hybrid Soft Robotic Bioreactors for Mimicking Multi-Axial Femoropopliteal Artery Mechanobiology

2021 ◽  
Author(s):  
Cody Fell ◽  
Trent L Brooks-Richards ◽  
Maria Ann Woodruff ◽  
Mark C Allenby
Keyword(s):  
Disease Modeling ◽  
The Body ◽  
Patient Specific ◽  
Soft Robotics ◽  
Mechanical Stimuli ◽  
Cell Alignment ◽  
Femoropopliteal Artery ◽  
Hemodynamic Forces ◽  
Type Iv

AbstractThe emerging field of soft robotics aims to emulate dynamic physiological locomotion. Soft robotics’ mimicry of naturally complex biomechanics makes them ideal platforms for exerting mechanical stimuli for patient-specific tissue maturation and disease modeling applications. Such platforms are essential for emulating highly flexible tissues such as the kneecap’s femoropopliteal artery (FPA), one of the most flexible arteries in the body, which flexes and bends during walking, standing, and crouching movements. The FPA is a frequent site of disease, where 80% of all peripheral artery diseases manifest, affecting over 200 million people worldwide. The complex biomechanical and hemodynamic forces within the FPA have been implicated in the frequent occurrence of PAD and lead to debilitating morbidities, such as limb-threatening ischemia. To better mimic these complex biomechanics, we developed an in-vitro bio-hybrid soft robot (BSR). First, Platsil OO-20 was identified as an ideal hyperelastomer for both cell culture and BSR fabrication using 3D printed molds. Then, employing a simulation-based design workflow, we integrated pneumatic network (PneuNet) actuators cast with Platsil OO-20, which extend in angular, longitudinal, and radial dimensions. Pressurizing the BSR PneuNets enabled a range of mechanical stimuli to be dynamically applied during tissue culture to mimic normal and diseased FPA flexions during daily walking and sitting poses, the most extreme being radial distensions of 20% and angular flexions of 140°. Finally, these designed, manufactured, and programmed vascular BSRs were seeded with mesenchymal stem cells and conditioned for 24 hours to highlight the effect of dynamic conditioning on cultured cell alignment, as well as type IV collagen production and the upregulation of smooth muscle phenotypes. Soft robotic bioreactor platforms that accurately mimic patient-, disease-, and lifestyle-specific mechanobiology will develop fundamental disease understanding, preoperative laboratory simulations for existing therapeutics, and biomanufacturing platforms for tissue-engineered implants.

scholarly journals Integrating Biosensors in Organs-on-Chip Devices: A Perspective on Current Strategies to Monitor Microphysiological Systems

Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 110 ◽  
Author(s):  
Erika Ferrari ◽  
Cecilia Palma ◽  
Simone Vesentini ◽  
Paola Occhetta ◽  
Marco Rasponi
Keyword(s):  
Imaging Techniques ◽  
Biological Models ◽  
Electromechanical Properties ◽  
Human Organs ◽  
Tissue Constructs ◽  
Microphysiological Systems ◽  
Metabolic Activities ◽  
On Chip ◽  
Chip Analysis

Organs-on-chip (OoC), often referred to as microphysiological systems (MPS), are advanced in vitro tools able to replicate essential functions of human organs. Owing to their unprecedented ability to recapitulate key features of the native cellular environments, they represent promising tools for tissue engineering and drug screening applications. The achievement of proper functionalities within OoC is crucial; to this purpose, several parameters (e.g., chemical, physical) need to be assessed. Currently, most approaches rely on off-chip analysis and imaging techniques. However, the urgent demand for continuous, noninvasive, and real-time monitoring of tissue constructs requires the direct integration of biosensors. In this review, we focus on recent strategies to miniaturize and embed biosensing systems into organs-on-chip platforms. Biosensors for monitoring biological models with metabolic activities, models with tissue barrier functions, as well as models with electromechanical properties will be described and critically evaluated. In addition, multisensor integration within multiorgan platforms will be further reviewed and discussed.

scholarly journals Genetic Suppressor Element 1 (GSE1) Promotes the Oncogenic and Recurrent Phenotypes of Castration-Resistant Prostate Cancer by Targeting Tumor-Associated Calcium Signal Transducer 2 (TACSTD2)

Cancers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 3959
Author(s):  
Oluwaseun Adebayo Bamodu ◽  
Yuan-Hung Wang ◽  
Chen-Hsun Ho ◽  
Su-Wei Hu ◽  
Chia-Da Lin ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Disease Progression ◽  
Therapy Resistance ◽  
Calcium Signal ◽  
Signal Transducer ◽  
Castration Resistance ◽  
Castration Resistant

Background: prostate cancer (PCa) is a principal cause of cancer-related morbidity and mortality. Castration resistance and metastasis are clinical challenges and continue to impede therapeutic success, despite diagnostic and therapeutic advances. There are reports of the oncogenic activity of genetic suppressor element (GSE)1 in breast and gastric cancers; however, its role in therapy resistance, metastasis, and susceptibility to disease recurrence in PCa patients remains unclear. Objective: this study investigated the role of aberrantly expressed GSE1 in the metastasis, therapy resistance, relapse, and poor prognosis of advanced PCa. Methods: we used a large cohort of multi-omics data and in vitro, ex vivo, and in vivo assays to investigate the potential effect of altered GSE1 expression on advanced/castration-resistant PCa (CRPC) treatment responses, disease progression, and prognosis. Results: using a multi-cohort approach, we showed that GSE1 is upregulated in PCa, while tumor-associated calcium signal transducer 2 (TACSTD2) is downregulated. Moreover, the direct, but inverse, correlation interaction between GSE1 and TACSTD2 drives metastatic disease, castration resistance, and disease progression and modulates the clinical and immune statuses of patients with PCa. Patients with GSE1highTACSTD2low expression are more prone to recurrence and disease-specific death than their GSE1lowTACSTD2high counterparts. Interestingly, we found that the GSE1–TACSTD2 expression profile is associated with the therapy responses and clinical outcomes in patients with PCa, especially those with metastatic/recurrent disease. Furthermore, we demonstrate that the shRNA-mediated targeting of GSE1 (shGSE1) significantly inhibits cell proliferation and attenuates cell migration and tumorsphere formation in metastatic PC3 and DU145 cell lines, with an associated suppression of VIM, SNAI2, and BCL2 and the concomitant upregulation of TACSTD2 and BAX. Moreover, shGSE1 enhances sensitivity to the antiandrogens abiraterone and enzalutamide in vitro and in vivo. Conclusion: these data provide preclinical evidence of the oncogenic role of dysregulated GSE1–TACSTD2 signaling and show that the molecular or pharmacological targeting of GSE1 is a workable therapeutic strategy for inhibiting androgen-driven oncogenic signals, re-sensitizing CRPC to treatment, and repressing the metastatic/recurrent phenotypes of patients with PCa.

scholarly journals Mechanical Strain-Enabled Reconstitution of Dynamic Environment in Organ-on-a-Chip Platforms: A Review

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 765
Author(s):  
Qianbin Zhao ◽  
Tim Cole ◽  
Yuxin Zhang ◽  
Shi-Yang Tang
Keyword(s):  
Cell Culture ◽  
Shear Stress ◽  
Cultured Cells ◽  
Mechanical Strain ◽  
3D Cell Culture ◽  
Small Scale ◽  
Mechanical Stimuli ◽  
Human Organ ◽  
Organ On A Chip

Organ-on-a-chip (OOC) uses the microfluidic 3D cell culture principle to reproduce organ- or tissue-level functionality at a small scale instead of replicating the entire human organ. This provides an alternative to animal models for drug development and environmental toxicology screening. In addition to the biomimetic 3D microarchitecture and cell–cell interactions, it has been demonstrated that mechanical stimuli such as shear stress and mechanical strain significantly influence cell behavior and their response to pharmaceuticals. Microfluidics is capable of precisely manipulating the fluid of a microenvironment within a 3D cell culture platform. As a result, many OOC prototypes leverage microfluidic technology to reproduce the mechanically dynamic microenvironment on-chip and achieve enhanced in vitro functional organ models. Unlike shear stress that can be readily generated and precisely controlled using commercial pumping systems, dynamic systems for generating proper levels of mechanical strains are more complicated, and often require miniaturization and specialized designs. As such, this review proposes to summarize innovative microfluidic OOC platforms utilizing mechanical actuators that induce deflection of cultured cells/tissues for replicating the dynamic microenvironment of human organs.

scholarly journals Bisphosphonates Reduce Smoking-Induced Osteoporotic-Like Alterations by Regulating RANKL/OPG in an Osteoblast and Osteoclast Co-Culture Model

2020 ◽  
Vol 22 (1) ◽  
pp. 53
Author(s):  
Sheng Zhu ◽  
Victor Häussling ◽  
Romina H. Aspera-Werz ◽  
Tao Chen ◽  
Bianca Braun ◽  
...  
Keyword(s):  
Alternative Therapy ◽  
Cigarette Smoke Extract ◽  
Matrix Remodeling ◽  
Nuclear Factor ◽  
Bone Homeostasis ◽  
Potential Mechanism ◽  
Culture Model ◽  
Receptor Activator ◽  
Culture Models

Co-culture models have become mandatory for obtaining better insights into bone homeostasis, which relies on the balance between osteoblasts and osteoclasts. Cigarette smoking (CS) has been proven to increase the risk of osteoporosis; however, there is currently no proven treatment for osteoporosis in smokers excluding cessation. Bisphosphonates (BPs) are classical anti-osteoclastic drugs that are commonly used in examining the suitability of bone co-culture systems in vitro as well as to verify the response to osteoporotic stimuli. In the present study, we tested the effects of BPs on cigarette smoke extract (CSE)-affected cells in the co-culture of osteoblasts and osteoclasts. Our results showed that BPs were able to reduce CSE-induced osteoporotic alterations in the co-culture of osteoblasts and osteoclasts such as decreased matrix remodeling, enhanced osteoclast activation, and an up-regulated receptor activator of nuclear factor (NF)-kB-ligand (RANKL)/osteoprotegerin (OPG) ratio. In summary, BPs may be an effective alternative therapy for reversing osteoporotic alterations in smokers, and the potential mechanism is through modulation of the RANKL/OPG ratio.

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