Geometrical effect on interaction of external cellular matrix and cardiomyocytes
Date Issued
2014
Date
2014
Author(s)
Chiu, Yu-Wei
Abstract
Enhanced expression of extracellular matrix (ECM) proteins will cause cardiomyocytes separation by fibrotic depositions, delay electrical signal transduction between cells, which may increase the incidence of arrhythmia. We observed atrial fibrillation patient’s atrial tissue by harmonic microscopy, analyzed the entropy of collagen by 2D Fourier transform method, and proved the disarray of collagen increased with disease severity. Recently, using self-assembling nanofiber peptide scaffold for three-dimensional (3D) culture environments for cardiac tissue engineering or regeneration therapy have become a promising field. While developing a proper 3D scaffold, altered 3D organization may have an influence on cell development and cause different cell behavior, which should be taken into consideration. We hypothesized that disordered nanopeptide scaffolds can mimic the chaotic spatial disarray related to cardiac fibrosis and have arrhythmogenic effects on cardiomyocytes. Primary mouse cardiomyocytes were cultured in 2D traditional and 3D disarray nanopeptide hydrogel scaffold (PuraMatrix) systems. Cardiomyocytes in 3D scaffolds showed irregular spontaneous contractile activity as compared with 2D culture controls. Calcium fluorimetric imaging revealed that basal intracellular calcium level increased 1.42-fold in cardiomyocytes cultured in the 3D scaffold, in vitro. The mRNA levels of calcium transport related channels on cell membrane were not increased but sarcoplasmic reticulum calcium transport ATPase, ryanodine 2 receptor elevated 2.14-fold and 2.33-fold in 3D compared with 2D. Further analysis of intracellular calcium sparks showed increased calcium efflux from sarcoplasmic reticulum into the cytoplasm, which could be related to malfunction of ryanodine 2 receptor. Connexin 43 increased 2.62-fold and immunofluorescence imaging revealed lateralization of the distribution of connexin 43 in 3D group. The secretion of B-type natriuretic peptide also increased in 3D. Although inflammation and fibrosis factors were not elevated, myofiber protein had higher expression in 3D group. These findings were not found in cardiomyocytes cultured in another anisotropic 3-dimensional collagen-GAG scaffold (GoMatrix). The mRNA expression of cells in the 3D group and mice cardiomyocytes were compared by microarray. Bioinformatics analysis showed these cells had similar change as those in hypertrophy or dilated cardiomyopathy. This study demonstrated that nanopeptide scaffold geometric irregularity can induce arrhythmogenic effect on cardiomyocytes. These limitations should be considered during cardiac tissue engineering. This 3D cardiomyocyte culture model will be useful for the design and improvement of engineered tissues for construction of cell model of cardiac arrhythmia, tissue engineering application, regeneration therapy and drug testing.
Subjects
心律不整
鈣離子
奈米縮胺酸生物支架
心肌細胞
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-D99421013-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):36f6b97a57c13aad902b5e7dcfc40f9d