Table 4.

Stretch-induced changes in fibroblast alpha-smooth muscle actin expression

Response	Main findings	Cell type	Coating and plate	Stretch machine	Stretch pattern	Stretch duration	Serum	Reference
Increase	αSMA mRNA and protein increased with stretch of one-day cultured fibroblasts (low basal αSMA level)	NRVF	Collagen I-coated magnetite beads	Ceramic permanent magnet	Static force perpendicular to cell surface	0.5, 1, 2, and 4 h	Serum-free	Wang et al., (2003)68
	αSMA-mRNA increased on collagen-VI, collagen IV, and laminin matrix	AHVF	BioFlex plate coated with collagen I, IV, VI, or laminin	Flexcell∗ FX-4000T	1 Hz, 10% equibiaxial	72 h	NS	Watson et al., (2014)108
	αSMA-mRNA increased by stretch. αSMA fibre formation with matrix stiffening	Adult mouse ventricular fibroblast	Collagen I-coated polyacrylamide gel adherent on PDMS membrane	Modified homemade stretch device	Static, 3% or 6% uniaxial	24 h and 48 h	10% FBS	Herum et al., (2017)90
	αSMA-positive cells increased after 48-h stretch at 0.5 and 1 Hz; not observed in p38-deficient fibroblasts	Mouse embryonic fibroblasts	NS	Flexcell	0.5 and 1.0 Hz	48 h	10% FBS	Molkentin et al. (2017)113
No change	αSMA mRNA unchanged with stretch on collagen I matrix	AHVF	BioFlex plate coated with collagen I, IV, VI, or laminin	Flexcell FX-4000T	1 Hz, 10% equibiaxial	72 h	NS	Watson et al., (2014)108
Decrease	αSMA mRNA and protein decreased with stretch on collagen I matrix, p38 dependent	ARVF	Collagen I, fibronectin, or fibronectin ED-A domain peptide-coated magnetite beads	Ceramic permanent magnet	Static force perpendicular to cell surface	15 min to 8 h	Serum-free	Wang et al., (2000)112
	αSMA mRNA and protein decreased with stretch of three-day cultured fibroblasts (high basal αSMA level), p38-dependent	NRVF	Collagen I-coated magnetite beads	Ceramic permanent magnet	Static force perpendicular to cell surface	0.5, 1, 2, and 4 h	Serum-free	Wang et al., (2003)68
	αSMA protein decreased by long-term stretch	NRVF	NS	Flexcell 4000	Short term: 1 Hz, 10%. Long term: 1 Hz, 5%.	2 h and 48 h	Serum-free	Hooper et al., (2012)43
	TGFβ-induced up-regulation of αSMA mRNA and protein. Stretch reduced TGFβ induction of αSMA	AHVF	Fibronectin-coated BioFlex plate	Flexercell∗ FX-4000 T	1 Hz, 10%	72 h	Serum-free	Watson et al., (2012)107

AHVF, adult human ventricular fibroblasts; ARVF, adult rat ventricular fibroblasts; αSMA, alpha-smooth muscle actin; FBS, foetal bovine serum; NRVF, neonatal rat ventricular fibroblasts; NS, not stated; p38,  p38 mitogen-activated protein kinase; TGFβ, transforming growth-factor β.

^*Please note that this company has used both Flexcell and Flexercell as names; we have retained the usage in each paper cited.