title: Upregulation of bone cell differentiation through immobilization within a synthetic extracellular matrix.
abstract: There is a need for new therapeutic strategies to treat bone defects caused by trauma, disease or tissue loss. Injectable systems for cell transplantation have the advantage of allowing the use of minimally invasive surgical procedures, and thus for less discomfort to patients. In the present study, it is hypothesized that Arg-Gly-Asp (RGD)-coupled in a binary (low and high molecular weight) injectable alginate composition is able to influence bone cell differentiation in a three-dimensional (3D) structure. Viability, metabolic activity, cytoskeleton organization, ultrastructure and differentiation (alkaline phosphatase (ALP), von Kossa, alizarin red stainings and osteocalcin quantification) of immobilized cells were assessed. Cells within RGD-modified alginate microspheres were able to establish more interactions with the synthetic extracellular matrix as visualized by confocal laser scanning microscope and transmission electron microscopy imaging, and presented a much higher level of differentiation (more intense ALP and mineralization stainings and higher levels of osteocalcin secretion) when compared to cells immobilized within unmodified alginate microspheres. These findings demonstrate that peptides covalently coupled to alginate were efficient in influencing cell behavior within this 3D system, and may provide adequate preparation of osteoblasts for cell transplantation.
authors.affiliation: INEB-Instituto de Engenharia Biomédica, Laboratório de Biomateriais, Porto, Portugal. mbe@ineb.up.pt <mbe@ineb.up.pt>
authors.forename: Marta B
authors.initials: MB
authors.lastname: Evangelista
authors.forename: Susan X
authors.initials: SX
authors.lastname: Hsiong
authors.forename: Rui
authors.initials: R
authors.lastname: Fernandes
authors.forename: Paula
authors.initials: P
authors.lastname: Sampaio
authors.forename: Hyun-Joon
authors.initials: HJ
authors.lastname: Kong
authors.forename: Cristina C
authors.initials: CC
authors.lastname: Barrias
authors.forename: Roberto
authors.initials: R
authors.lastname: Salema
authors.forename: Mário A
authors.initials: MA
authors.lastname: Barbosa
authors.forename: David J
authors.initials: DJ
authors.lastname: Mooney
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Granja
mesh_terms: D016475:3T3 Cells; D000464:Alginates / Q000737:chemistry / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003599:Cytoskeleton / Q000378:metabolism; D005109:Extracellular Matrix / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry / Q000494:pharmacology; D006603:Hexuronic Acids / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D009842:Oligopeptides / Q000737:chemistry; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D015675:Osteocalcin / Q000378:metabolism
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D009842:Oligopeptides; D015675:Osteocalcin; C047981:arginyl-glycyl-aspartic acid; D020723:Glucuronic Acid; D000469:Alkaline Phosphatase