title: Characterizing the efficacy of calcium channel agonist-release strategies for bone tissue engineering applications.
abstract: We have previously reported on the use of Bay K8644-release strategies in combination with perfusion-compression bioreactor systems for up regulating bone formation in three-dimensional PLLA scaffolds. Here we report on the analysis of Bay activity following its release from our PLLA scaffolds over the culture period imposed in our tissue engineering protocol using UV spectroscopy in combination with whole cell patch clamping techniques. Bay was released continually from scaffolds within the physiological range required for agonist activity (1-10 microM). Patch clamping allowed for the effects of Bay released from scaffolds to be monitored directly with respect to osteoblast electrophysiology. A characteristic shift in the current-voltage (I-V) relationship of L-type VOCC currents was observed in rat osteoblast sarcoma (ROS) cells patched in a solution with Bay released from scaffolds following 14 and 28 days incubation, with statistically significant differences observed in peak currents compared to non-Bay controls. An increase in the magnitude of the peak inward currents was also noted. The electrophysiological response of osteoblasts in the presence of Bay released from scaffolds demonstrates that the released Bay is stable and maintains its bioactivity following culture of up to 28 days.
authors.affiliation: Institute of Science and Technology in Medicine, School of Medicine, Keele University, Thornburrow Drive, Hartshill, Stoke-on-Trent. Staffs ST4 7QB, UK. m.a.wood@keele.ac.uk
authors.forename: M A
authors.initials: MA
authors.lastname: Wood
authors.forename: S
authors.initials: S
authors.lastname: Hughes
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: A J
authors.initials: AJ
authors.lastname: El Haj
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D019149:Bioreactors; D002120:Calcium Channel Agonists / Q000737:chemistry / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations; D004355:Drug Stability; D019344:Lactic Acid / Q000737:chemistry; D008564:Membrane Potentials; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D010012:Osteogenesis; D011091:Polyesters; D011108:Polymers / Q000737:chemistry; D016062:Porosity; D051381:Rats; D012995:Solubility; D013997:Time Factors; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D003692:Delayed-Action Preparations; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester