tissue-engineered-graft-for-circumferential-esophageal-reconstruction

Tissue-Engineered Graft for Circumferential Esophageal Reconstruction in Rats

The use of biocompatible materials for circumferential esophageal reconstruction is a technically challenging task in rats and requires an optimal implant ...

Inje University, Gimhae

To investigate the expansion of hematopoietic stem/progenitor cells (HSPCs) from umbilical cord blood using extracellular matrix (ECM) protein-coated three-dimensional hierarchical scaffolds.

A three-dimensional hierarchical scaffold fabricated by a combined rapid prototyping technique and electrospinning process to expand hematopoietic stem/progenitor cells.

It has been widely recognized and proved that biophysical factors for mimicking in vivo conditions should be also considered to have stem cells differentiated into desired cell type in vitro along with biochemical factors. Biophysical factors include substrate and biomechanical conditions. This study focused on the effect of biomimetic mechanical stretching along with changes in substrate topography to influence on cardiomyogenic differentiation of human mesenchymal stem cells (hMSCs). Elastic micropatterned substrates were made to mimic the geometric conditions surrounding cells in vivo. To mimic biomechanical conditions due to beating of the heart, mechanical stretching was applied parallel to the direction of the pattern (10% elongation, 0.5 Hz, 4 h/day). Suberoylanilide hydroxamic acid (SAHA) was used as a biochemical factor. The micropatterned substrate was found more effective in the alignment of cytoskeleton and cardiomyogenic differentiation compared with flat substrate. Significantly higher expression levels of related markers [GATA binding protein 4 (GATA4), troponin I, troponin T, natriuretic peptide A (NPPA)] were observed when mechanical stretching was engaged on micropatterned substrate. In addition, 4 days of mechanical stretching was associated with higher levels of expression than 2 days of stretching. These results indicate that simultaneous engagement of biomimetic environment such as substrate pattern and mechanical stimuli effectively promotes the cardiomyogenic differentiation of hMSCs in vitro. The suggested method which tried to mimic in vivo microenvironment would provide systematic investigation to control cardiomyogenic differentiation of hMSCs.

Simultaneous engagement of mechanical stretching and surface pattern promotes cardiomyogenic differentiation of human mesenchymal stem cells.

To control the oscillatory behavior of the intracellular calcium ([Ca]) concentration in endothelial cells via mechanical factors (i.e., various hydrostatic pressures) because [Ca] in these cells is affected by blood pressure.

Mechanical stimuli modulate intracellular calcium oscillations: a pathological model without chemical cues.

Mechanical stimuli play important roles in the proliferation and differentiation of adult stem cells. However, few studies on their effects on induced pluripotent stem cells (iPSCs) have been published.

Effects of mechanical stimulation on the reprogramming of somatic cells into human-induced pluripotent stem cells.

Unlike stable and immobile cell line conditions, animal hearts contract and relax to pump blood throughout the body. Mitochondria play an essential role by producing biological energy molecules to maintain heart function. In this study, we assessed the effect of heart mimetic cyclic stretch on mitochondria in a cardiac cell line. To mimic the geometric and biomechanical conditions surrounding cells in vivo, cyclic stretching was performed on HL-1 murine cardiomyocytes seeded onto an elastic micropatterned substrate (10% elongation, 0.5 Hz, 4 h/day). Cell viability, semi-quantitative Q-PCR, and western blot analyses were performed in non-stimulated control and cyclic stretch stimulated HL-1 cell lines. Cyclic stretch significantly increased the expression of mitochondria biogenesis-related genes (TUFM, TFAM, ERRα, and PGC1-α) and mitochondria oxidative phosphorylation-related genes (PHB1 and CYTB). Western blot analysis confirmed that cyclic stretch increased protein levels of mitochondria biogenesis-related proteins (TFAM, and ERRα) and oxidative phosphorylation-related proteins (NDUFS1, UQCRC, and PHB1). Consequently, cyclic stretch increased mitochondrial mass and ATP production in treated cells. Our results suggest that cyclic stretch transcriptionally enhanced mitochondria biogenesis and oxidative phosphorylation without detrimental effects in a cultured cardiac cell line.

Jung-Woog Shin

Department of Biomedical Engineering

Inje University, Gimhae

Tissue-Engineered Graft for Circumferential Esophageal Reconstruction in Rats