K. McEwan's research while affiliated with University of Ottawa and other places

Publications (14)

Article
Islet transplantation is an emerging strategy for treating patients with type 1 diabetes mellitus. Although the proof of concept for cellular replacement therapy in diabetes has been firmly established, vascularity of the transplant site and the long-term survival and function of transplanted islets remains suboptimal. In the present study, human c...
Article
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Islet transplantation to treat type 1 diabetes (T1D) has shown varied long-term success, due in part to insufficient blood supply to maintain the islets. In the current study, collagen and collagen:chitosan (10:1) hydrogels, +/- circulating angiogenic cells (CACs), were compared for their ability to produce a pro-angiogenic environment in a strepto...
Article
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Cell transplantation for regenerative medicine has become an appealing therapeutic method; however, stem and progenitor cells are not always freshly available. Cryopreservation offers a way to freeze cells as they are generated, for storage and transport until required for therapy. This study was performed to assess the feasibility of cryopreservin...
Article
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Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl LewisX (sLeX), to guide ske...
Article
Full-text available
Although many regenerative cell therapies are being developed to replace or regenerate ischaemic muscle, the lack of vasculature and poor persistence of the therapeutic cells represent major limiting factors to successful tissue restoration. In response to ischaemia, stromal cell-derived factor-1 (SDF-1) is up-regulated by the affected tissue to st...
Article
Injectable hydrogels are increasingly being developed for biomedical applications due to their ability to be delivered in a minimally invasive manner. One potential use for such materials is in cell delivery for cardiac regeneration. While the materials' properties are often characterized, how these properties (and in particular gelation) are affec...

Citations

... Cells were seeded on fibronectin-coated plates (20 μg/plate) in EBM-2 (Clonetics) supplemented with EGM-2-MV SingleQuots (Clonetics). After 4 days in culture, an adherent heterogeneous CAC population was generated, which was previously characterized (Sofrenovic et al., 2012). CACs were lifted from the plates using PBS, and count and viability were assessed using a Vi-Cell counter (Beckman Coulter) via the Trypan blue exclusion method, prior to embedding them in matrices. ...
... Biomaterials that closely mimic organ nanostructures could be used to replicate nano-to-macro approach to human organ development, and proper biomaterial placement is necessary to direct cellular self-assembly [37,38] . The elastic modulus and molding process characteristics of common printable biomaterials (collagen [39,40] , fibrin [41,42] , alginate [43] , chitosan [44,45] , agarose [46] , Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV) [47] , and other polymers [48,49] ) are summarized in Figure 1B. To print physically similar microenvironments in vitro, appropriate mechanical properties and modeling processes of the materials used must be considered [50,51] . ...
... In the pancreas, BM is predominant: it surrounds the acinar cells of the exocrine pancreas, duct vessels, and pancreatic islets (53). More specifically, pancreatic islets are embedded in ECM-based structures with a specific and balanced protein composition, hierarchical organization, and determined architectural features, which are strictly related to the correct endocrine function (54)(55)(56)(57). Islet ECM can be subdivided into an external and incomplete peripheral capsule, the peri-islet ECM, and an internal ECM, the inner matrix (IM) (58). ...
... All tissue samples were sectioned and randomly allocated to immediate cell culture (fresh tissue), immediate cryopreservation or delayed cryopreservation after 24 hours of refrigeration (4˚C) in cardioplegia solution (lactated ringers, 2% St Thomas solution, 5 mEq NaHCO3 and 10 mEq KCl; Thermo Fisher Scientific). Tissue samples were cryopreserved to -80˚C within 5% dimethyl sulfoxide, 6% fetal bovine serum within Iscove's Modified Dulbecco's Medium [9]. One month later, cryopreserved tissue specimen vials were recovered in a 37˚C water bath prior to processing. ...
... The ECM also serves as a reservoir for growth factors, including HGF and IGF-1, with which matrix metalloproteinases can interact to promote regeneration (Kok and Barton 2021). ECM actually promotes muscle regeneration (Kuraitis et al. 2012), in part by haptotaxis-induced myoblast migration (Roveimiab et al. 2020). And, ECM proteins mediate adhesion or attachment of muscle stem cells, meaning the ECM mediates satellite cell responses to mechanical activity and tissue perturbation (Li et al. 2018;Moyle et al. 2020). ...
... Wang and colleagues reported that the SDF-1/CXCR4 pathway was critical for MSCs to migrate and improve the functional restoration of SG in mice with Sjögren's-like disease 36 . Moreover, local injections of SDF-1 mobilized progenitor cells from bone marrow to the circulation and enhanced vascularisation 37 . The relationship between CD26 and angiogenesis remains controversial. ...
... Further, they were incorporated into an injectable collagen-based matrix for the treatment of ischemic hindlimb muscle. This local delivery increased the migration of progenitor cells, and also improved the recruitment of angiogenic cells (Kuraitis et al. 2011). ...
... 15 Additionally, it is known that the topography of a material is important as an alternate signaling mechanism to control many properties related to vascularization, including adhesion, migration, and differentiation. 15,16 We have previously optimized the copolymers in our collagenbased matrix, 18,20,21 but the most favorable concentration of the cross-linker remains to be determined. In this study, the cross-linker-dependent properties of the collagen-based matrix are characterized to facilitate the optimization of a biomaterial able to support cellular grafts, such as islets for the treatment of type 1 diabetes. ...