Extracellular Matrix of Mechanically Stretched Cardiac Fibroblasts Improves Viability and Metabolic Activity of Ventricular Cells

Abstract

Background: In heart, the extracellular matrix (ECM), produced by cardiac fibroblasts, is a potent regulator of heart,s function and growth, and provides a supportive scaffold for heart cells in vitro and in vivo. Cardiac fibroblasts are subjected to mechanical loading all the time in vivo. Therefore, the influences of mechanical loading on formation and bioactivity of cardiac fibroblasts, ECM should be investigated.Methods: Rat cardiac fibroblasts were cultured on silicone elastic membranes and stimulated with mechanical cyclic stretch. After removing the cells, the ECMs coated on the membranes were prepared, some ECMs were treated with heparinase II (GAG-lyase), then the collagen, glycosaminoglycan (GAG) and ECM proteins were assayed. Isolated neonatal rat ventricular cells were seeded on ECM-coated membranes, the viability and lactate dehydrogenase (LDH) activity of the cells after 1-7 days of culture was assayed. In addition, the ATPase activity and related protein level, glucose consumption ratio and lactic acid production ratio of the ventricular cells were analyzed by spectrophotometric methods and Western blot.Results: The cyclic stretch increased collagen and GAG levels of the ECMs, and elevated protein levels of collagen I and fibronectin. Compared with the ECMs produced by unstretched cardiac fibroblasts, the ECMs of mechanically stretched fibroblasts improved viability and LDH activity, elevated the Na+/K+-ATPase activity, sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity and SERCA 2a protein level, glucose consumption ratio and lactic acid production ratio of ventricular cells seeded on them. The treatment with heparinase II reduced GAG levels of these ECMs, and lowered these metabolism-related indices of ventricular cells cultured on the ECMs.Conclusions: Mechanical stretch promotes ECM formation of cardiac fibroblasts in vitro, the ECM of mechanically stretched cardiac fibroblasts improves metabolic activity of ventricular cells cultured in vitro, and the GAG of the ECMs is involved in regulating metabolic activity of ventricular cells.

Cardiac Fibrotic Remodeling on a Chip with Dynamic Mechanical Stimulation

“…In a combined mechanical strain and hypoxia in vitro model, compared with 2% stretching strain (1 Hz), 8% stretching strain attenuated both CFs remodeling and profibrotic responses taking place in hypoxia . Cyclic stretch (4% and 8%, 1 Hz) of fibroblasts on silicone membranes was shown to increase the expression and production of collagen and fibronectin . Cyclic biaxial stretch (10%, 1 Hz) enhanced the expression of α‐SMA and collagen I (Col‐I) in rat CFs .…”

Potential strain-dependent mechanisms defining matrix alignment in healing tendons

“…Our theoretical agent-based model simulations predicted that strain-induced collagen damage combined with strain-induced increases in collagen production can indeed give rise to divergence – i.e., a strain regime where increased strains yield increased content but decreased alignment – but only if there is a very sharp transition from low to high collagen deposition rates at exactly the right strain value. Experimental evidence strongly supports the idea that strain or load can modulate collagen synthesis: in vitro measurements of strain-dependent collagen deposition by fibroblasts typically show increases on the order of 2-fold from unloaded to highly loaded constructs (Butt and Bishop 1997; Lee et al 1999; Papakrivopoulou et al 2004; Atance et al 2004; Husse et al 2007; Balestrini and Billiar 2009; Guo et al 2013; Watson et al 2014), while increased loading of healing tendons in vivo (exercise vs. complete unloading) gives rise to ∼3-fold increases in matrix content (Thomopoulos et al 2003; Galatz et al 2009). However, it is less clear to what extent fiber damage actually occurs in the healing supraspinatus tendons that motivated our model (Thomopoulos et al 2003; Galatz et al 2006, 2009).…”

Trends in Decellularized Extracellular Matrix Bioinks for 3D Printing: Inspiring a new Kind of Medicine

“…However, another study showed that fd-ECM was able to induce proliferation of MC3T3-E1 cells whilst an osteoblast-derived ECM was able to promote osteogenic differentiation of the same cells [137]. An ECM derived from mechanically stretched cardiac fibroblasts was shown to improve the metabolic activity of ventricular cells [138]. The same study showed that a proteoglycan-attached glycosaminoglycan was responsible for the observed effect [138].…”

“…An ECM derived from mechanically stretched cardiac fibroblasts was shown to improve the metabolic activity of ventricular cells [138]. The same study showed that a proteoglycan-attached glycosaminoglycan was responsible for the observed effect [138]. It has been shown that application of skin products containing human fibroblast-derived growth factors can result in significant upregulation of genes encoding ECM components including collagens and elastin [139].…”