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He S, Azar DA, Esfahani FN, Azar GA, Shazly T, Saeidi N. Mechanoscopy: A Novel Device and Procedure for in vivo Detection of Chronic Colitis in Mice. Inflamm Bowel Dis 2022; 28:1143-1150. [PMID: 35325126 PMCID: PMC9340527 DOI: 10.1093/ibd/izac046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Indexed: 12/09/2022]
Abstract
BACKGROUND Gut stiffening caused by fibrosis plays a critical role in the progression of inflammatory bowel disease (IBD) and colon cancer. Previous studies have characterized the biomechanical response of healthy and pathological gut, with most measurements obtained ex vivo. METHODS Here, we developed a device and accompanying procedure for in vivo quantification of gut stiffness, termed mechanoscopy. Mechanoscopy includes a flexible balloon catheter, pressure sensor, syringe pump, and control system. The control system activates the balloon catheter and performs automated measurements of the gut stress-strain biomechanical response. RESULTS A gut stiffness index (GSI) is identified based on the slope of the obtained stress-strain response. Using a colitis mouse model, we demonstrated that GSI positively correlates with the extent of gut fibrosis, the severity of mucosal damage, and the infiltration of immune cells. Furthermore, a critical strain value is suggested, and GSI efficiently detects pathological gut fibrotic stiffening when the strain exceeds this value. CONCLUSIONS Based on these results, we envision that mechanoscopy and GSI will facilitate the clinical diagnosis of IBD.
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Affiliation(s)
| | | | - Farid Nasr Esfahani
- Division of Gastrointestinal and Oncologic Surgery, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA
- Center for Engineering in Medicine and Surgery, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA
- Shriners Hospital for Children, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Golara A Azar
- Department of Electrical Engineering and Computer Sciences, University of California Los Angeles, Los Angeles, CA, USA
| | - Tarek Shazly
- Department of Mechanical Engineering, University of South Carolina, Columbia, SC, USA
| | - Nima Saeidi
- Address correspondence to: Nima Saeidi, 51 Blossom St., Room 207, Boston, MA, 02114, USA ()
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Kraus X, Pflaum M, Thoms S, Jonczyk R, Witt M, Scheper T, Blume C. A pre-conditioning protocol of peripheral blood derived endothelial colony forming cells for endothelialization of tissue engineered constructs. Microvasc Res 2020; 134:104107. [PMID: 33212112 DOI: 10.1016/j.mvr.2020.104107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/08/2020] [Accepted: 11/12/2020] [Indexed: 02/07/2023]
Abstract
In regenerative medicine, autologous endothelial colony forming cells (ECFCs) bear the greatest potential to be used for surface endothelialization of tissue engineered constructs, as they are easily attainable and possess a high proliferation rate. The aim of this study was to develop a standardized pre-conditioning protocol under dynamic conditions simulating the physiology of human circulation to improve the formation of a flow resistant monolayer of ECFCs and to enhance the antithrombogenicity of the endothelial cells. The main focus of the study was to consequently compare the cellular behavior under a steady laminar flow against a pulsatile flow. Mononuclear cells were isolated out of peripheral blood (PB) buffy coats and plated on uncoated tissue culture flasks in anticipation of guidelines for Advanced Therapy Medicinal Products. ECFCs were identified by typical surface markers such as CD31, CD146 and VE-Cadherin. To explore the effects of dynamic cultivation, ECFCs and human umbilical vein endothelial cells were comparatively cultured under either laminar or pulsatile (1 Hz) flow conditions with different grades of shear stress (5 dyn/cm2versus 20 dyn/cm2). High shear stress of 20 dyn/cm2 led to a significant upregulation of the antithrombotic gene marker thrombomodulin in both cell types, but only ECFCs orientated and elongated significantly after shear stress application forming a confluent endothelial cell layer. The work therefore documents a suitable protocol to pre-condition PB-derived ECFCs for sustainable endothelialization of blood contacting surfaces and provides essential knowledge for future cultivations in bioreactor systems.
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Affiliation(s)
- Xenia Kraus
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany.
| | - Michael Pflaum
- Department for Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, 30625 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Stefanie Thoms
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Rebecca Jonczyk
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Martin Witt
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Thomas Scheper
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Cornelia Blume
- Leibniz University Hannover, Institute of Technical Chemistry, Callinstr. 5, D-30167 Hannover, Germany; Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
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Prim DA, Lane BA, Ferruzzi J, Shazly T, Eberth JF. Evaluation of the Stress-Growth Hypothesis in Saphenous Vein Perfusion Culture. Ann Biomed Eng 2020; 49:487-501. [PMID: 32728831 DOI: 10.1007/s10439-020-02582-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/22/2020] [Indexed: 01/02/2023]
Abstract
The great saphenous vein (GSV) has served as a coronary artery bypass graft (CABG) conduit for over 50 years. Despite prevalent use, first-year failure rates remain high compared to arterial autograft options. Amongst other factors, vein graft failure can be attributed to material and mechanical mismatching that lead to apoptosis, inflammation, and intimal-medial hyperplasia. Through the implementation of the continuum mechanical-based theory of "stress-mediated growth and remodeling," we hypothesize that the mechanical properties of porcine GSV grafts can be favorably tuned for CABG applications prior to implantation using a prolonged but gradual transition from venous to arterial loading conditions in an inflammatory and thrombogenic deficient environment. To test this hypothesis, we used a hemodynamic-mimetic perfusion bioreactor to guide remodeling through stepwise incremental changes in pressure and flow over the course of 21-day cultures. Biaxial mechanical testing of vessels pre- and post-remodeling was performed, with results fit to structurally-motivated constitutive models using non-parametric bootstrapping. The theory of "small-on-large" was used to describe appropriate stiffness moduli, while histology and viability assays confirmed microstructural adaptations and vessel viability. Results suggest that stepwise transition from venous-to-arterial conditions results in a partial restoration of circumferential stretch and circumferential, but not axial, stress through vessel dilation and wall thickening in a primarily outward remodeling process. These remodeled tissues also exhibited decreased mechanical isotropy and circumferential, but not axial, stiffening. In contrast, only increases in axial stiffness were observed using culture under venous perfusion conditions and those tissues experienced moderate intimal resorption.
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Affiliation(s)
- David A Prim
- Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA
| | - Brooks A Lane
- Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA
| | - Jacopo Ferruzzi
- Biomedical Engineering Department, Boston University, Boston, MA, USA
| | - Tarek Shazly
- Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA.,Mechanical Engineering Department, University of South Carolina, Columbia, SC, USA
| | - John F Eberth
- Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA. .,Cell Biology and Anatomy Department (CBA), SOM, University of South Carolina (USC), Bldg.1, Rm. C-36, Columbia, SC, 29208, USA.
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Prim DA, Menon V, Hasanian S, Carter L, Shazly T, Potts JD, Eberth JF. Perfusion Tissue Culture Initiates Differential Remodeling of Internal Thoracic Arteries, Radial Arteries, and Saphenous Veins. J Vasc Res 2018; 55:255-267. [PMID: 30179877 DOI: 10.1159/000492484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 07/23/2018] [Indexed: 01/26/2023] Open
Abstract
Adaptive remodeling processes are essential to the maintenance and viability of coronary artery bypass grafts where clinical outcomes depend strongly on the tissue source. In this investigation, we utilized an ex vivo perfusion bioreactor to culture porcine analogs of common human bypass grafts: the internal thoracic artery (ITA), the radial artery (RA), and the great saphenous vein (GSV), and then evaluated samples acutely (6 h) and chronically (7 days) under in situ or coronary-like perfusion conditions. Although morphologically similar, primary cells harvested from the ITA illustrated lower intimal and medial, but not adventitial, cell proliferation rates than those from the RA or GSV. Basal gene expression levels were similar in all vessels, with only COL3A1, SERPINE1, FN1, and TGFB1 being differentially expressed prior to culture; however, over half of all genes were affected nominally by the culturing process. When exposed to coronary-like conditions, RAs and GSVs experienced pathological remodeling not present in ITAs or when vessels were studied in situ. Many of the remodeling genes perturbed at 6 h were restored after 7 days (COL3A1, FN1, MMP2, and TIMP1) while others (SERPINE1, TGFB1, and VCAM1) were not. The findings elucidate the potential mechanisms of graft failure and highlight strategies to encourage healthy ex vivo pregraft conditioning.
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Affiliation(s)
- David A Prim
- Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, USA
| | - Vinal Menon
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, South Carolina, USA
| | - Shahd Hasanian
- Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, USA
| | - Laurel Carter
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, South Carolina, USA
| | - Tarek Shazly
- Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, USA.,Mechanical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, USA
| | - Jay D Potts
- Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, USA.,Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, South Carolina, USA
| | - John F Eberth
- Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, South Carolina, .,Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, South Carolina,
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