title: An airway smooth muscle cell niche under physiological pulsatile flow culture using a tubular dense collagen construct.
abstract: Bioengineered tissue equivalents should provide physiologically relevant biochemical and mechanical cues to support the growth and differentiation of seeded cells. Herein, tubular dense collagen constructs (TDCCs) with collagen content comparable to native extracellular matrix were used to investigate the effect of shear stress alone (i.e. under laminar fluid flow), and shear stress in combination with circumferential strain (i.e. under pulsatile fluid flow) on the proliferation, alignment, and phenotype of three-dimensionally (3D) seeded airway smooth muscle cells (ASMCs). In addition, the effect of ASMC-mediated remodelling on TDCC matrix morphological and mechanical properties was investigated. Compared to static culture, pulsatile flow increased seeded ASMC growth by 70%, improved the homogeneity of cell distribution within the TDCCs and induced differential cellular alignment depending on the primary stimuli. Specifically, within the inner wall, where shear stress is predominant, ASMCs were aligned parallel to fluid flow direction, while within the outer wall ASMCs were aligned parallel to the circumferential strain (perpendicular to fluid flow). In contrast, under laminar flow, ASMCs were aligned parallel to fluid flow direction within both walls. Compared to laminar flow, pulsatile flow resulted in increased positive staining for α-smooth muscle actin, and in up-regulated typical ASMC contractile markers suggesting that circumferential strain modulates ASMC differentiation. Pulsatile flow also caused a 60 and 30% increase in collagen density within both acellular and cellular TDCCs, respectively, which was reflected in an increased apparent modulus. Compared to static culture, pulsatile stimulation of cellular constructs resulted in 70% higher circumferential strength. The TDCCs provide ASMC niche for greater insight into the responses of 3D seeded SMCs to physiologically equivalent in vitro dynamic conditioning.
authors.affiliation: Department of Mining and Materials Engineering, McGill University, Quebec, Canada H3A 2B2.
authors.forename: Chiara E
authors.initials: CE
authors.lastname: Ghezzi
authors.forename: Paul-André
authors.initials: PA
authors.lastname: Risse
authors.forename: Benedetto
authors.initials: B
authors.lastname: Marelli
authors.forename: Naser
authors.initials: N
authors.lastname: Muja
authors.forename: Jake E
authors.initials: JE
authors.lastname: Barralet
authors.forename: James G
authors.initials: JG
authors.lastname: Martin
authors.forename: Showan N
authors.initials: SN
authors.lastname: Nazhat
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D001980:Bronchi / Q000166:cytology*; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D003094:Collagen / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D011673:Pulsatile Flow / Q000187:drug effects*; D051381:Rats; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D003094:Collagen