Scaffolds for Engineering Smooth Muscle Under Cyclic Mechanical Strain Conditions

2000 ◽  
Vol 122 (3) ◽  
pp. 210-215 ◽  
Author(s):  
Byung-Soo Kim ◽  
David J. Mooney

Cyclic mechanical strain has been demonstrated to enhance the development and function of engineered smooth muscle (SM) tissues, but appropriate scaffolds for engineering tissues under conditions of cyclic strain are currently lacking. These scaffolds must display elastic behavior, and be capable of inducing an appropriate smooth muscle cell (SMC) phenotype in response to mechanical signals. In this study, we have characterized several scaffold types commonly utilized in tissue engineering applications in order to select scaffolds that exhibit elastic properties under appropriate cyclic strain conditions. The ability of the scaffolds to promote an appropriate SMC phenotype in engineered SM tissues under cyclic strain conditions was subsequently analyzed. Poly(L-lactic acid)-bonded polyglycolide fiber-based scaffolds and type I collagen sponges exhibited partially elastic mechanical properties under cyclic strain conditions, although the synthetic polymer scaffolds demonstrated significant permanent deformation after extended times of cyclic strain application. SM tissues engineered with type I collagen sponges subjected to cyclic strain were found to contain more elastin than control tissues, and the SMCs in these tissues exhibited a contractile phenotype. In contrast, SMCs in control tissues exhibited a structure more consistent with the nondifferentiated, synthetic phenotype. These studies indicate the appropriate choice of a scaffold for engineering tissues in a mechanically dynamic environment is dependent on the time frame of the mechanical stimulation, and elastic scaffolds allow for mechanically directed control of cell phenotype in engineered tissues. [S0148-0731(00)00103-5]

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Martin Liu ◽  
Angelos Karagiannis ◽  
Matthew Sis ◽  
Srivatsan Kidambi ◽  
Yiannis Chatzizisis

Objectives: To develop and validate a 3D in-vitro model of atherosclerosis that enables direct interaction between various cell types and/or extracellular matrix. Methods and Results: Type I collagen (0.75 mg/mL) was mixed with human artery smooth muscle cells (SMCs; 6x10 5 cells/mL), medium, and water. Human coronary artery endothelial cells (HCAECs; 10 5 /cm 2 ) were plated on top of the collagen gels and activated with oxidized low density lipoprotein cholesterol (LDL-C). Monocytes (THP-1 cells; 10 5 /cm 2 ) were then added on top of the HCAECs. Immunofluorescence showed the expression of VE-cadherin by HCAECs (A, B) and α-smooth muscle actin by SMCs (A). Green-labelled LDL-C particles were accumulated in the subendothelial space, as well as in the cytoplasm of HCAECs and SMCs (C). Activated monocytes were attached to HCAECs and found in the subendothelial area (G-I). Both HCAECs and SMCs released IL-1β, IL-6, IL-8, PDGF-BB, TGF-ß1, and VEGF. Scanning and transmission electron microscopy showed the HCAECs monolayer forming gap junctions and the SMCs (D-F) and transmigrating monocytes within the collagen matrix (G-I). Conclusions: In this work, we presented a novel, easily reproducible and functional in-vitro experimental model of atherosclerosis that has the potential to enable in-vitro sophisticated molecular and drug development studies.


1990 ◽  
Vol 265 (2) ◽  
pp. 461-469 ◽  
Author(s):  
A H Ang ◽  
G Tachas ◽  
J H Campbell ◽  
J F Bateman ◽  
G R Campbell

Enzymically isolated rabbit aortic smooth-muscle cells (SMC) in the first few days of primary culture express a ‘contractile phenotype’, but with time these cells modulate to a ‘synthetic phenotype’. Synthetic-state SMC are able to proliferate, and, provided that they undergo fewer than 5 cumulative population doublings, return to the contractile phenotype after reaching confluency [Campbell, Kocher, Skalli, Gabbiani & Campbell (1989) Arteriosclerosis 9, 633-643]. The present study has determined the synthesis of collagen, at the protein and mRNA levels, by cultured SMC as they undergo a change in phenotypic state. The results show that, upon modulating to the synthetic phenotype, SMC synthesized 25-30 times more collagen than did contractile cells. At the same time, non-collagen-protein synthesis increased only 5-6-fold, indicating a specific stimulation of collagen synthesis. Steady-state mRNA levels are also elevated, with alpha 2(I) and alpha 1(III) mRNA levels 30 times and 20 times higher respectively, probably reflecting increased transcriptional activity. Phenotypic modulation was also associated with an alteration in the relative proportions of type I and III collagens synthesized, contractile SMC synthesizing 78.1 +/- 3.6% (mean +/- S.D.) type I collagen and 17.5 +/- 4.7% type III collagen, and synthetic cells synthesizing 90.3 +/- 2.0% type I collagen and 5.8% +/- 1.8% type III collagen. Enrichment of type I collagen was similarly noted at the mRNA level. On return to the contractile state, at confluency, collagen production and the percentage of type I collagen decreased. This further illustrates the close association between the phenotypic state of SMC and their collagen-biosynthetic phenotype.


1999 ◽  
Vol 277 (5) ◽  
pp. G1074-G1080 ◽  
Author(s):  
Jorge A. Gutierrez ◽  
Hilary A. Perr

Intestinal muscle undergoes stretch intermittently during peristalsis and persistently proximal to obstruction. The influence of this pervasive biomechanical force on developing smooth muscle cell function remains unknown. We adapted a novel in vitro system to study whether stretch modulates transforming growth factor-β1 (TGF-β1) and type I collagen protein and component α1 chain [α1(I) collagen] expression in fetal human intestinal smooth muscle cells. Primary confluent cells at 20-wk gestation, cultured on flexible silicone membranes, were subjected to two brief stretches or to 18 h tonic stretch. Nonstretched cultures served as controls. TGF-β1 protein was measured by ELISA and type I collagen protein was assayed by Western blot. TGF-β1 and α1(I) collagen mRNA abundance was determined by Northern blot analysis, quantitated by phosphorimaging, and normalized to 18S rRNA. Transcription was examined by nuclear run-on assay. Tonic stretch increased TGF-β1 protein 40%, type I collagen protein 100%, TGF-β1 mRNA content 2.16-fold, and α1(I) collagen mRNA 3.80-fold and enhanced transcription of TGF-β1 and α1(I) collagen by 3.1- and 4.25-fold, respectively. Brief stretch stimulated a 50% increase in TGF-β1 mRNA content but no change in α1(I) collagen. Neutralizing anti-TGF-β1 ablated stretch-mediated effects on α1(I) collagen. Therefore, stretch upregulates transcription for TGF-β1, which stimulates α1(I) collagen gene expression in smooth muscle from developing gut.


1994 ◽  
Vol 3 (6) ◽  
pp. 481-492 ◽  
Author(s):  
Keiichi Kanda ◽  
Takehisa Matsuda

The effect of tensile stress on the orientation and phenotype of arterial smooth muscle cells (SMCs) cultured in three-dimensional (3D) type I collagen gels was morphologically investigated. Ring-shaped hybrid tissues were prepared by thermal gelation of a cold mixed solution of type I collagen and SMCs derived from bovine aorta. The tissues were subjected to three different modes of tensile stress. They were floated (isotonic control), stretched isometrically (static stress) and periodically stretched and recoiled by 5% above and below the resting tissue length at 60 RPM frequency (dynamic stress). After incubation for up to four wk, the tissues were investigated under a light microscope (LM) and a transmission electron microscope (TEM). Hematoxylin and eosinstained LM samples revealed that, irrespective of static or dynamic stress loading, SMCs in stress-loaded tissues exhibited elongated bipolar spindle shape and were regularly oriented parallel to the direction of the strain, whereas those in isotonic control tissues were polygonal or spherical and had no preferential orientation. In Azan-stained samples, collagen fiber bundles in isotonic control tissues were somewhat retracted around the polygonal SMCs to form a random network. On the other hand, those in statically and dynamically stressed tissues were accumulated and prominently oriented parallel to the stretch direction. Ultrastructural investigation using a TEM showed that SMCs in control and statically stressed tissues were almost totally filled with synthetic organelles such as rough endoplasmic reticulums, free ribosomes, Golgi complexes and mitochondria, indicating that the cells remained in the synthetic phenotype. On the other hand, SMCs in dynamically stressed tissues had increased fractions of contractile apparatus, such as myofilaments, dense bodies and extracellular filamentous materials equivalent to basement membranes, that progressed with incubation time. These results indicate that periodic stretch, in concert with 3-D extracellular collagen matrices, play a significant role in the phenotypic modulation of SMCs from the synthetic to the contractile state, as well as cellular and biomolecular orientation.


2018 ◽  
Vol 9 ◽  
pp. 204173141878982 ◽  
Author(s):  
Elisa Costa ◽  
Cristina González-García ◽  
José Luis Gómez Ribelles ◽  
Manuel Salmerón-Sánchez

Articular chondrocytes are difficult to grow, as they lose their characteristic phenotype following expansion on standard tissue culture plates. Here, we show that culturing them on surfaces of poly(L-lactic acid) of well-defined microtopography allows expansion and maintenance of characteristic chondrogenic markers. We investigated the dynamics of human chondrocyte dedifferentiation on the different poly(L-lactic acid) microtopographies by the expression of collagen type I, collagen type II and aggrecan at different culture times. When seeded on poly(L-lactic acid), chondrocytes maintained their characteristic hyaline phenotype up to 7 days, which allowed to expand the initial cell population approximately six times without cell dedifferentiation. Maintenance of cell phenotype was afterwards correlated to cell adhesion on the different substrates. Chondrocytes adhesion occurs via the α5 β1 integrin on poly(L-lactic acid), suggesting cell–fibronectin interactions. However, α2 β1 integrin is mainly expressed on the control substrate after 1 day of culture, and the characteristic chondrocytic markers are lost (collagen type II expression is overcome by the synthesis of collagen type I). Expanding chondrocytes on poly(L-lactic acid) might be an effective solution to prevent dedifferentiation and improving the number of cells needed for autologous chondrocyte transplantation.


Biomaterials ◽  
2005 ◽  
Vol 26 (3) ◽  
pp. 311-318 ◽  
Author(s):  
A IGNATIUS ◽  
H BLESSING ◽  
A LIEDERT ◽  
C SCHMIDT ◽  
C NEIDLINGERWILKE ◽  
...  

2011 ◽  
Vol 34 (3) ◽  
pp. 138 ◽  
Author(s):  
Zhi Zhang ◽  
Guang Chu ◽  
Hong-Xian Wu ◽  
Ni Zou ◽  
Bao-Gui Sun ◽  
...  

Objective: The goal of this study was to investigate the crosstalk between vascular endothelial cells (ECs) and smooth muscle cells (SMCs) using a three-dimensional (3-D) co-culture model. In addition, the role of IL-8 in this crosstalk was investigated. Methods: A 3-D co-culture model was constructed using a Transwell chamber system and type I collagen gel. Human umbilical artery smooth muscle cells (HUASMCs) were suspended in the gel and added to the upper compartment of the Transwell. Human umbilical vein endothelial cells (HUVECs) were then grown on the surface of the gel. The growth of HUASMCs was tested with a CFDA SE cell proliferation kit. IL-8 and other bioactive substances were investigated by ELISA and real-time PCR. The alteration of p-ERK expression related to the change in IL-8 levels was also examined by Western blot analysis. Results: The proliferation rate of HUASMCs in the 3-D co-culture model was 0.679 ± 0.057. Secretion and transcription of VEGF, t-PA, NO and VCAM-1 in the 3-D co-culture model were different than in single (2-D) culture. When 3-D co-cultured, IL-8 released by HUVECs was significantly increased (2.35 ± 0.16 fold) (P﹤0.05) and the expression of VCAM-1 from HUASMCs was reduced accordingly (0.55±0.09 fold). In addition, increasing or decreasing the level of IL-8 changed the level of p-ERK and VCAM-1 expression. The reduction of VCAM-1, resulting from increased IL-8, could be blocked by the MEK inhibitor, PD98059. Conclusion: Crosstalk between HUVECs and HUASMCs occurred and was probably mediated by IL-8 in this 3-D co-culture model.


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