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Hewes SA, Ahmad FN, Connell JP, Grande-Allen KJ. Technique for Rapidly Forming Networks of Microvessel-Like Structures. Tissue Eng Part C Methods 2024. [PMID: 38568845 DOI: 10.1089/ten.tec.2023.0318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
Modeling organ-blood barriers through the inclusion of microvessel networks within in vitro tissue models could lead to more physiologically accurate results, especially since organ-blood barriers are crucial to the normal function, drug transport, and disease states of vascularized organs. Microvessel networks are difficult to form, since they push the practical limits of most fabrication methods, and it is difficult to coax vascular cells to self-assemble into structures larger than capillaries. Here, we present a method for rapidly forming networks of microvessel-like structures using sacrificial alginate structures. Specifically, we encapsulated endothelial cells within short alginate threads, and then embedded them in collagen gel. Following enzymatic degradation of the alginate, the collagen gel contained a network of hollow channels seeded with cells, all surrounding a perfusable central channel. This method uses a 3D-printed coaxial extruder and syringe pumps to generate short threads in a way that is repeatable and easily transferrable to other labs. The cell-laden, sacrificial alginate threads can be frozen after fabrication and thawed before embedding without significant loss of cell viability. The ability to freeze the threads enables future scale-up and ease of use. Within millifluidic devices that restrict access to media, the threads enhance cell survival under static conditions. These results indicate the potential for use of this method in a range of tissue engineering applications.
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Affiliation(s)
- Sarah A Hewes
- Department of Bioengineering, Rice University, Houston, Texas, USA
| | - Fariha N Ahmad
- Department of Bioengineering, Rice University, Houston, Texas, USA
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Hewes SA, Ahmad FN, Connell JP, Grande-Allen KJ. Technique for rapidly forming networks of microvessel-like structures. bioRxiv 2024:2023.06.22.546165. [PMID: 37961290 PMCID: PMC10634690 DOI: 10.1101/2023.06.22.546165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Modelling organ-blood barriers through the inclusion of microvessel networks within in vitro tissue models could lead to more physiologically accurate results, especially since organ-blood barriers are crucial to the normal function, drug transport, and disease states of vascularized organs. Microvessel networks are difficult to form, since they push the practical limit of most fabrication methods, and it is difficult to coax vascular cells to self-assemble into structures larger than capillaries. Here we present a method for rapidly forming networks of microvessel-like structures using sacrificial, alginate structures. Specifically, we encapsulated endothelial cells within short alginate threads, then embedded them in collagen gel. Following enzymatic degradation of the alginate, the collagen gel contained a network of hollow channels seeded with cells, all surrounding a perfusable central channel. This method uses a 3D printed coaxial extruder and syringe pumps to generate short threads in a way that is repeatable and easily transferrable to other labs. The cell-laden, sacrificial alginate threads can be frozen after fabrication and thawed before embedding without significant loss of cell viability. The ability to freeze the threads enables future scale up and ease of use. Within millifluidic devices that restrict access to media, the threads enhance cell survival under static conditions. These results indicate the potential for use of this method in a range of tissue engineering applications.
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Affiliation(s)
- Sarah A. Hewes
- Department of Bioengineering, Rice University, Houston, TX
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Wilson RL, Hewes SA, Rajan A, Lin SC, Bomidi C, Iida T, Estes MK, Maresso AW, Grande-Allen KJ. A Millifluidic Perfusion Cassette for Studying the Pathogenesis of Enteric Infections Using Ex-Vivo Organoids. Ann Biomed Eng 2021; 49:1233-1244. [PMID: 33409849 DOI: 10.1007/s10439-020-02705-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
To generate physiologically-relevant experimental models, the study of enteric diarrheal diseases is turning increasingly to advanced in vitro models that combine ex vivo, stem cell-derived "organoid" cell lines with bioengineered culture environments that expose them to mechanical stimuli, such as fluid flow. However, such approaches require considerable technical expertise with both microfabrication and organoid culture, and are, therefore, inaccessible to many researchers. For this reason, we have developed a perfusion system that is simple to fabricate, operate, and maintain. Its dimensions approximate the volume and cell culture area of traditional 96-well plates and allow the incorporation of fastidious primary, stem cell-derived cell lines with only minimal adaptation of their established culture techniques. We show that infections with enteroaggregative E. coli and norovirus, common causes of infectious diarrhea, in the system display important differences from static models, and in some ways better recreate the pathophysiology of in vivo infections. Furthermore, commensal strains of bacteria can be added alongside the pathogens to simulate the effects of a host microbiome on the infectious process. For these reasons, we believe that this perfusion system is a powerful, yet easily accessible tool for studying host-pathogen interactions in the human intestine.
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Affiliation(s)
- Reid L Wilson
- Department of Bioengineering, Rice University, 6100 Main St, MS-142, Houston, TX, 77005, USA.,Medical Scientist Training Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Sarah A Hewes
- Department of Bioengineering, Rice University, 6100 Main St, MS-142, Houston, TX, 77005, USA
| | - Anubama Rajan
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Shih-Ching Lin
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Carolyn Bomidi
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Takanori Iida
- Department of Bioengineering, Rice University, 6100 Main St, MS-142, Houston, TX, 77005, USA
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Anthony W Maresso
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - K Jane Grande-Allen
- Department of Bioengineering, Rice University, 6100 Main St, MS-142, Houston, TX, 77005, USA.
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Hewes SA, Wilson RL, Estes MK, Shroyer NF, Blutt SE, Grande-Allen KJ. In Vitro Models of the Small Intestine: Engineering Challenges and Engineering Solutions. Tissue Eng Part B Rev 2020; 26:313-326. [PMID: 32046599 PMCID: PMC7462033 DOI: 10.1089/ten.teb.2019.0334] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/29/2020] [Indexed: 12/12/2022]
Abstract
Pathologies affecting the small intestine contribute significantly to the disease burden of both the developing and the developed world, which has motivated investigation into the disease mechanisms through in vitro models. Although existing in vitro models recapitulate selected features of the intestine, various important aspects have often been isolated or omitted due to the anatomical and physiological complexity. The small intestine's intricate microanatomy, heterogeneous cell populations, steep oxygen gradients, microbiota, and intestinal wall contractions are often not included in in vitro experimental models of the small intestine, despite their importance in both intestinal biology and pathology. Known and unknown interdependencies between various physiological aspects necessitate more complex in vitro models. Microfluidic technology has made it possible to mimic the dynamic mechanical environment, signaling gradients, and other important aspects of small intestinal biology. This review presents an overview of the complexity of small intestinal anatomy and bioengineered models that recapitulate some of these physiological aspects.
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Affiliation(s)
- Sarah A. Hewes
- Department of Bioengineering, Rice University, Houston, Texas, USA
| | - Reid L. Wilson
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
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