Brian Roman1,2, Shweta Anil Kumar1,2, Shane C Allen3, Monica Delgado1,2, Sabastian Moncayo1,2, Andres M Reyes4, Laura J Suggs3, Ramana Chintalapalle5, Chunqiang Li4,6, Binata Joddar7,8. 1. Inspired Materials & Stem-Cell Based Tissue Engineering Laboratory (IMSTEL), El Paso, USA. 2. Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W University Avenue, El Paso, TX, 79968, USA. 3. Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. 4. Department of Physics, The University of Texas at El Paso, 500 W University Avenue, El Paso, TX, 79968, USA. 5. Department of Mechanical Engineering, The University of Texas at El Paso, 500 W University Avenue, El Paso, TX, 79968, USA. 6. Border Biomedical Research Center, University of Texas at El Paso, 500 W University Avenue, El Paso, TX, 79968, USA. 7. Inspired Materials & Stem-Cell Based Tissue Engineering Laboratory (IMSTEL), El Paso, USA. bjoddar@utep.edu. 8. Border Biomedical Research Center, University of Texas at El Paso, 500 W University Avenue, El Paso, TX, 79968, USA. bjoddar@utep.edu.
Abstract
PURPOSE: To develop a novel model composed solely of Col I and Col III with the lower and upper limits set to include the ratios of Col I and Col III at 3:1 and 9:1 in which the structural and mechanical behavior of the resident CM can be studied. Further, the progression of fibrosis due to change in ratios of Col I:Col III was tested. METHODS: Collagen gels with varying Col I:Col III ratios to represent a healthy (3:1) and diseased myocardial tissue were prepared by manually casting them in wells. Absorbance assay was performed to confirm the gelation of the gels. Rheometric analysis was performed on each of the collagen gels prepared to determine the varying stiffnesses and rheological parameters of the gels made with varying ratios of Col I:Col III. Second Harmonic Generation (SHG) was performed to observe the 3D characterization of the collagen samples. Scanning Electron microscopy was used for acquiring cross sectional images of the lyophilized collagen gels. AC16 CM (human) cell lines were cultured in the prepared gels to study cell morphology and behavior as a result of the varying collagen ratios. Cellular proliferation was studied by performing a Cell Trace Violet Assay and the applied force on each cell was measured by means of Finite Element Analysis (FEA) on CM from each sample. RESULTS: Second harmonic generation microscopy used to image Col I, displayed a decrease in acquired image intensity with an increase in the non-second harmonic Col III in 3:1 gels. SEM showed a fiber-rich structure in the 3:1 gels with well-distributed pores unlike the 9:1 gels or the 1:0 controls. Rheological analysis showed a decrease in substrate stiffness with an increase of Col III, in comparison with other cases. CM cultured within 3:1 gels exhibited an elongated rod-like morphology with an average end-to-end length of 86 ± 28.8 µm characteristic of healthy CM, accompanied by higher cell growth in comparison with other cases. Finite element analysis used to estimate the forces exerted on CM cultured in the 3:1 gels, showed that the forces were well dispersed, and not concentrated within the center of cells, in comparison with other cases. CONCLUSION: This study model can be adopted to simulate various biomechanical environments in which cells crosstalk with the Collagen-matrix in diseased pathologies to generate insights on strategies for prevention of fibrosis.
PURPOSE: To develop a novel model composed solely of Col I and Col III with the lower and upper limits set to include the ratios of Col I and Col III at 3:1 and 9:1 in which the structural and mechanical behavior of the resident CM can be studied. Further, the progression of fibrosis due to change in ratios of Col I:Col III was tested. METHODS: Collagen gels with varying Col I:Col III ratios to represent a healthy (3:1) and diseased myocardial tissue were prepared by manually casting them in wells. Absorbance assay was performed to confirm the gelation of the gels. Rheometric analysis was performed on each of the collagen gels prepared to determine the varying stiffnesses and rheological parameters of the gels made with varying ratios of Col I:Col III. Second Harmonic Generation (SHG) was performed to observe the 3D characterization of the collagen samples. Scanning Electron microscopy was used for acquiring cross sectional images of the lyophilized collagen gels. AC16 CM (human) cell lines were cultured in the prepared gels to study cell morphology and behavior as a result of the varying collagen ratios. Cellular proliferation was studied by performing a Cell Trace Violet Assay and the applied force on each cell was measured by means of Finite Element Analysis (FEA) on CM from each sample. RESULTS: Second harmonic generation microscopy used to image Col I, displayed a decrease in acquired image intensity with an increase in the non-second harmonic Col III in 3:1 gels. SEM showed a fiber-rich structure in the 3:1 gels with well-distributed pores unlike the 9:1 gels or the 1:0 controls. Rheological analysis showed a decrease in substrate stiffness with an increase of Col III, in comparison with other cases. CM cultured within 3:1 gels exhibited an elongated rod-like morphology with an average end-to-end length of 86 ± 28.8 µm characteristic of healthy CM, accompanied by higher cell growth in comparison with other cases. Finite element analysis used to estimate the forces exerted on CM cultured in the 3:1 gels, showed that the forces were well dispersed, and not concentrated within the center of cells, in comparison with other cases. CONCLUSION: This study model can be adopted to simulate various biomechanical environments in which cells crosstalk with the Collagen-matrix in diseased pathologies to generate insights on strategies for prevention of fibrosis.
Authors: Alexandre J S Ribeiro; Yen-Sin Ang; Ji-Dong Fu; Renee N Rivas; Tamer M A Mohamed; Gadryn C Higgs; Deepak Srivastava; Beth L Pruitt Journal: Proc Natl Acad Sci U S A Date: 2015-09-28 Impact factor: 11.205
Authors: Pragati Pandey; William Hawkes; Junquiang Hu; William Valentine Megone; Julien Gautrot; Narayana Anilkumar; Min Zhang; Liisa Hirvonen; Susan Cox; Elisabeth Ehler; James Hone; Michael Sheetz; Thomas Iskratsch Journal: Dev Cell Date: 2018-01-26 Impact factor: 12.270