In JoVE (1)

Other Publications (10)

Articles by Alexander Seifalian in JoVE

Other articles by Alexander Seifalian on PubMed

Oxygen-Generating Biomaterials: A New, Viable Paradigm for Tissue Engineering?

Trends in Biotechnology. Dec, 2016  |  Pubmed ID: 27325423

There have been many attempts to provide sufficient nutrients, especially oxygen, to engineered large tissues to overcome the effects of hypoxia or poor vascularization. Delivering sufficient oxygen to the transplanted cells is one of the most critical issues that affects cell survival and correct maturation of engineered tissues. An emerging approach is using 3D scaffolds made from oxygen-generating biomaterials to tackle transport limitations deep within the engineered tissues. This class of biomaterials has opened a new window for overcoming the challenges associated with ischemia occurring within large tissue constructs. This review critically assesses oxygen-generating reagents, the main approaches for developing oxygen-generating biomaterials, and their potential as 3D scaffolds for regenerative medicine in a clinical setting.

Stem Cells for Tissue Engineered Vascular Bypass Grafts

Artificial Cells, Nanomedicine, and Biotechnology. Jun, 2016  |  Pubmed ID: 27327775

Despite great advances in tissue engineering, there have been very few reports on the successful clinical use of small-diameter tissue-engineered vascular grafts (TEVGs). Small-diameter (<6 mm internal diameter) is considered as unmet clinical need. This review critically examines the role of stem cells that have been proposed and used in development of TEVGs, and assesses the viability of such graft to clinical pathway. With over 20 years of expertise in development of bypass graft and a number of grafts under clinical trial, this team will offer potential areas for future research that may help improve the current state-of-the-art technology.

An Arsenal of Magnetic Nanoparticles; Perspectives in the Treatment of Cancer

Nanomedicine (London, England). Aug, 2016  |  Pubmed ID: 27480599

Nanomedicine is an emerging field, which constitutes a new direction in the treatment of cancer. Magnetic nanoparticles (MNPs) can circumvent vascular tissue to concentrate at the site of the tumor. Under the influence of an external, alternating magnetic field, MNPs generate high temperatures within the tumor and ablate malignant cells while inflicting minimal damage to healthy host tissue. Due to their theranostic properties, they constitute a promising candidate for the treatment of cancer. A critical review of the type, size and therapeutic effect of different MNPs is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry, with a few studies moving to clinical trials within the next 5 years.

The Influence of Silica Nanoparticles on Small Mesenteric Arterial Function

Nanomedicine (London, England). Aug, 2016  |  Pubmed ID: 27480920

To determine the influence of silica nanoparticles (SiNPs) on small arterial function; both ex vivo and in vivo.

Nanotechnology for the Diagnosis and Treatment of Diseases

Nanomedicine (London, England). Aug, 2016  |  Pubmed ID: 27509317

A New Transcatheter Heart Valve Concept (the TRISKELE): Feasibility in an Acute Preclinical Model

EuroIntervention : Journal of EuroPCR in Collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology. Sep, 2016  |  Pubmed ID: 27639743

The aim of this study was to introduce and demonstrate the feasibility in an acute preclinical model of a new transcatheter heart valve concept with a self-expanding wire frame, polymeric leaflets and a sealing component.

Haemoxygenase Modulates Cytokine Induced Neutrophil Chemoattractant in Hepatic Ischemia Reperfusion Injury

World Journal of Gastroenterology. Sep, 2016  |  Pubmed ID: 27672274

To investigate the hepatic microcirculatory changes due to Haemoxygenase (HO), effect of HO inhibition on remote ischemic preconditioning (RIPC) and modulation of CINC.

Towards Reconstruction of Epithelialized Cartilages from Autologous Adipose Tissue-derived Stem Cells

Journal of Tissue Engineering and Regenerative Medicine. Nov, 2016  |  Pubmed ID: 27804241

Deformities of the upper airways, including those of the nose and throat, are typically corrected by reconstructive surgery. The use of autologous somatic stem cells for repair of defects could improve quality and outcomes of such operations. The present study explored the ability of paediatric adipose-derived stem cells (pADSCs), a readily available source of autologous stem cells, to generate a cartilage construct with a functional epithelium. Paediatric ADSCs seeded on the biodegradable nanocomposite polymer, polyhedral oligomeric silsesquioxane poly(ϵ-caprolactone-urea) urethane (POSS-PCL), proliferated and differentiated towards mesenchymal lineages. The ADSCs infiltrated three-dimensional POSS-PCL nanoscaffold and chondroid matrix was observed throughout chondrogenically induced samples. In ovo chorioallantoic membrane-grafted ADSC-nanoscaffold composites were enwrapped by host vessels indicating good compatibility in an in vivo system. Furthermore, pADSCs could be induced to transdifferentiate towards barrier-forming epithelial-like cells. By combining differentiation protocols, it was possible to generate epithelial cell lined chondrogenic micromasses from the same pADSC line. This proof-of-concept study appears to be the first to demonstrate that individual pADSC lines can differentiate towards two different germ lines and be successfully co-cultured. This has important implications for bioengineering of paediatric airways and further confirms the plastic nature of ADSCs. Copyright © 2016 John Wiley & Sons, Ltd.

Conjugation with RGD Peptides and Incorporation of Vascular Endothelial Growth Factor Are Equally Efficient for Biofunctionalization of Tissue-Engineered Vascular Grafts

International Journal of Molecular Sciences. Nov, 2016  |  Pubmed ID: 27854352

The blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) has recently been considered promising for vascular tissue engineering. However, it was shown that PHBV/PCL grafts require biofunctionalization to achieve high primary patency rate. Here we compared immobilization of arginine-glycine-aspartic acid (RGD)-containing peptides and the incorporation of vascular endothelial growth factor (VEGF) as two widely established biofunctionalization approaches. Electrospun PHBV/PCL small-diameter grafts with either RGD peptides or VEGF, as well as unmodified grafts were implanted into rat abdominal aortas for 1, 3, 6, and 12 months following histological and immunofluorescence assessment. We detected CD31⁺/CD34⁺/vWF⁺ cells 1 and 3 months postimplantation at the luminal surface of PHBV/PCL/RGD and PHBV/PCL/VEGF, but not in unmodified grafts, with the further observation of CD31⁺CD34(-)vWF⁺ phenotype. These cells were considered as endothelial and produced a collagen-positive layer resembling a basement membrane. Detection of CD31⁺/CD34⁺ cells at the early stages with subsequent loss of CD34 indicated cell adhesion from the bloodstream. Therefore, either conjugation with RGD peptides or the incorporation of VEGF promoted the formation of a functional endothelial cell layer. Furthermore, both modifications increased primary patency rate three-fold. In conclusion, both of these biofunctionalization approaches can be considered as equally efficient for the modification of tissue-engineered vascular grafts.

Osteogenic Potential of Stem Cells-seeded Bioactive Nanocomposite Scaffolds: A Comparative Study Between Human Mesenchymal Stem Cells Derived from Bone, Umbilical Cord Wharton's Jelly, and Adipose Tissue

Journal of Biomedical Materials Research. Part B, Applied Biomaterials. Nov, 2016  |  Pubmed ID: 27862947

Bone regeneration is considered as an unmet clinical need, the aim of this study is to investigate the osteogenic potential of three different mesenchymal stem cells (MSCs) derived from human bone marrow (BM-MSCs), umbilical cord Wharton's jelly (UC-MSCs), and adipose (AD-MSCs) seeded on a recently developed nanocomposite scaffold (bioactive glass/gelatin) implanted in rat animal models with critical size calvarial defects. In this study, after isolation, culture, and characterization, the MSCs were expanded and seeded on the scaffolds for in vitro and in vivo studies. The adhesion, proliferation, and viability of the cells on the scaffolds evaluated in vitro, showed that the scaffolds were biocompatible for further examinations. In order to evaluate the scaffolds in vivo, rat animal models with critical size calvarial defects were randomly categorized in four groups and treated with the scaffolds. The animals were sacrificed at the time points of 4 and 12 weeks of post-implantation, bone healing process were investigated. The histological and immunohistological observations showed (p < 0.01) higher osteogenesis capacity in the group treated with BM-MSCs/scaffolds compared to the other groups. However, the formation of new angiogenesis was evidently higher in the defects filled with UC-MSCs/scaffolds. This preliminary study provides promising data for further clinical trials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

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