Varying Ratios of Collagen I and III for the Study of Fibrotic Conditions in Tissue Engineering

Maintenance of collagen I (Col I) and III (Col III) in a 3:1 ratio is necessary to promote cardiac health. Increase in the relative amount of Col I within the myocardium, leads to an imbalance of Col I:III during cardiac fibrosis, which has damaging effects on cardiomyocytes (CM). To represent fibrous- and normal-cardiac tissue, gels composed of Col I:III ratios of 9:1 and 3:1 were developed and used to study resultant changes in CM function. Second harmonic generation (SHG) microscopy, used to image Col I fibers, displayed a decrease in image intensity with the addition of 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 1:0 controls. Rheological analysis demonstrated a decrease in substrate stiffness with the increase of Col III when compared to other cases. Finite element analysis used to estimate the forces exerted on CM cultured in 3:1 gels showed that the forces were well dispersed and not concentrated within the center of cells, in comparison with other cases. The presented model can be adopted to simulate a variety of biomechanical environments where cells crosstalk with the Col-matrix in diseased pathologies, generating insight on strategies for the prevention of fibrosis