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161 results on '"McFetridge, Peter S."'

16. Flow with variable pulse frequencies accelerates vascular recellularization and remodeling of a human bioscaffold.

Author

Van de Walle, Aurore B. and McFetridge, Peter S.

Abstract

Despite significant advances in vascular tissue engineering, the ideal graft has not yet been developed and autologous vessels remain the gold standard substitutes for small diameter bypass procedures. Here, we explore the use of a flow field with variable pulse frequencies over the regeneration of an ex vivo‐derived human scaffold as vascular graft. Briefly, human umbilical veins were decellularized and used as scaffold for cellular repopulation with human smooth muscle cells (SMC) and endothelial cells (EC). Over graft development, the variable flow, which mimics the real‐time cardiac output of an individual performing daily activities (e.g., resting vs. exercising), was implemented and compared to the commonly used constant pulse frequency. Results show marked differences on SMC and EC function, with changes at the molecular level reflecting on tissue scales. First, variable frequencies significantly increased SMC proliferation rate and glycosaminoglycan production. These results can be tied with the SMC gene expression that indicates a synthetic phenotype, with a significant downregulation of myosin heavy chain. Additionally and quite remarkably, the variable flow frequencies motivated the re‐endothelialization of the grafts, with a quiescent‐like structure observed after 10 days of conditioning, contrasting with the low surface coverage and unaligned EC observed under constant frequency (CF). Besides, the overall biomechanics of the generated grafts (conditioned with both pulsed and CFs) evidence a significant remodeling after 55 days of culture, depicted by high burst pressure and Young's modulus. These last results demonstrate the positive recellularization and remodeling of a human‐derived scaffold toward an arterial vessel. [ABSTRACT FROM AUTHOR]

Published
2021
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22. The effect of terminal sterilization on structural and biophysical properties of a decellularized collagen-based scaffold; implications for stem cell adhesion

Author

Matuska, Andrea M. and McFetridge, Peter S.

Subjects
Hot Temperature, Tissue Scaffolds, Cell Adhesion, Humans, Sterilization, Mesenchymal Stem Cells, Collagen, Article
Abstract

Terminal sterilization induces physical and chemical changes in the extracellular matrix (ECM) of ex vivo-derived biomaterials due to their aggressive mechanism of action. Prior studies have focused on how sterilization affects the mechanical integrity of tissue-based biomaterials but have rarely characterized effects on early cellular interaction, which is indicative of the biological response. Using a model fibro-cartilage disc scaffold, these investigations compare the effect of three common sterilization methods [peracetic acid (PAA), gamma irradiation (GI), and ethylene oxide (EtO)] on a range of material properties and characterized early cellular interactions. GI and EtO produced unfavorable structural damage that contributed to inferior cell adhesion. Conversely, exposure to PAA resulted in limited structural alterations while inducing chemical modifications that favored cell attachment. Results suggest that the sterilization approach can be selected to modulate biomaterial properties to favor cellular adhesion and has relevance in tissue engineering and regenerative medicine applications. Furthermore, the study of cellular interactions with modified biomaterials in vitro provides information of how materials may react in subsequent clinical applications.

Published
2014

33. Single-Walled Carbon Nanotubes Targeted to the Tumor Vasculature for Breast Cancer Treatment

Author

OKLAHOMA UNIV NORMAN, Harrison, Roger G., Resasco, Daniel E., McFetridge, Peter S., OKLAHOMA UNIV NORMAN, Harrison, Roger G., Resasco, Daniel E., and McFetridge, Peter S.

Abstract

This project explores a novel treatment of breast cancer that uses single-walled carbon nanotubes (SWNTs) in photodynamic therapy, in which the SWNTs are targeted to the endothelial cells that line the tumor vasculature. The purpose of this project is to evaluate this treatment concept using human endothelial cells in vitro. Recombinant annexin V has been produced in good purity and high yield, and it has been shown to bind strongly to plastic-immobilized phosphatidylserine (PS), with a dissociation constant (Kd ) of 5.1 nM. A new method was developed for conjugating amino groups of annexin V to single-walled carbon nanotubes (SWNTs) that retains the strong absorbance of the SWNTs at 980 nm. This method uses the linker fluorenylmethoxycarbonyl (Fmoc)-amine-PEG-succinimidyl carboxy methyl ester. The loading of annexin V on the SWNTs was high (7.7 mg protein/mg SWNTs). Human endothelial cells grown in vitro could be killed almost completely when SWNT-Fmoc-PEG-annexin V was bound to the cells and with laser light at 980 nm and an energy density of 195 J/cm2. By contract, there was no harm to cells with SWNT-Fmoc-PEG-annexin V bound and no laser treatment, and there was no harm to cells with no SWNT-Fmoc-PEG-annexin V bound receiving laser treatment.

Published
2009

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