| 1. |
- Alghfeli, Latifa, et al.
(författare)
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Synthesis of scaffold-free, three dimensional, osteogenic constructs following culture of skeletal osteoprogenitor cells on glass surfaces
- 2021
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Ingår i: Bone Reports. - : ELSEVIER. - 2352-1872. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efficient differentiation of stem cells into three-dimensional (3D) osteogenic construct is still an unmet challenge. These constructs can be crucial for patients with bone defects due to congenital or traumatic reasons. The modulation of cell fate and function as a consequence of interaction with the physical and chemical properties of materials is well known. Methods: The current study has examined the osteogenic differentiation potential of human skeletal populations following culture on glass surfaces, as a monolayer, or in glass tubes as a pellet culture. The 3D prosperities were assessed morphometrically and the differentiation was evaluated through molecular characterization as well as matrix formation. Results: Early temporal expression of alkaline phosphatase expression of skeletal populations was observed following culture on glass surfaces. Skeletal populations seeded on glass tubes, adhered as a monolayer to the tube base and subsequently formed 3D pellets at the air-media interface. The pellets cultured on glass displayed 4.9 +/- 1.3 times the weight and 2.9 +/- 0.1 the diameter of their counterpart cultured in plastic tubes and displayed enhanced production of osteogenic matrix proteins, such a collagen I and osteonectin. The size and weight of the pellets correlated with surface area in contrast to cell numbers seeded. Global DNA methylation level was decreased in pellets cultured on glass. In contrast, gene expression analysis confirmed upregulation extracellular matrix proteins and osteogenesis-related growth factors. Conclusion: This simple approach to the culture of skeletal cells on glass tubes provides a scaffold-free, 3D construct platform for generating pellets enabling analysis and evaluation of tissue development and integration of multiple constructs with implications for tissue repair and regenerative application on scale-up.
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| 2. |
- El-Serafi, Ahmed Taher, 1977-, et al.
(författare)
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Epigenetic modifiers influence lineage commitment of human bone marrow stromal cells: Differential effects of 5-aza-deoxycytidine and trichostatin A
- 2011
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Ingår i: Differentiation. - London, United Kingdom : Elsevier. - 0301-4681 .- 1432-0436. ; 81:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- Clinical imperatives for new bone to replace or restore the function of traumatized or bone lost as a consequence of age or disease has led to the need for therapies or procedures to generate bone for skeletal applications. However, current in vitro methods for the differentiation of human bone marrow stromal cells (HBMSCs) do not, to date, produce homogeneous cell populations of the osteogenic or chondrogenic lineages. As epigenetic modifiers are known to influence differentiation, we investigated the effects of the DNA demethylating agent 5-aza-2′-deoxycytidine (5-aza-dC) or the histone deacetylase inhibitor trichostatin A (TSA) on osteogenic and chondrogenic differentiation. Monolayer cultures of HBMSCs were treated for 3 days with the 5-aza-dC or TSA, followed by culture in the absence of modifiers. Cells were subsequently grown in pellet culture to determine matrix production. 5-aza-dC stimulated osteogenic differentiation as evidenced by enhanced alkaline phosphatase activity, increased Runx-2 expression in monolayer, and increased osteoid formation in 3D cell pellets. In pellets cultured in chondrogenic media, TSA enhanced cartilage matrix formation and chondrogenic structure. These findings indicate the potential of epigenetic modifiers, as agents, possibly in combination with other factors, to enhance the ability of HBMSCs to form functional bone or cartilage with significant therapeutic implications therein.
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| 3. |
- Kim, Yang-Hee, et al.
(författare)
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Bisphosphonate nanoclay edge-site interactions facilitate hydrogel self-assembly and sustained growth factor localization
- 2020
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Nanoclays have generated interest in biomaterial design for their ability to enhance the mechanics of polymeric materials and impart biological function. As well as their utility as physical cross-linkers, clays have been explored for sustained localization of biomolecules to promote in vivo tissue regeneration. To date, both biomolecule-clay and polymer-clay nanocomposite strategies have utilised the negatively charged clay particle surface. As such, biomolecule-clay and polymer-clay interactions are set in competition, potentially limiting the functional enhancements achieved. Here, we apply specific bisphosphonate interactions with the positively charged clay particle edge to develop self-assembling hydrogels and functionalized clay nanoparticles with preserved surface exchange capacity. Low concentrations of nanoclay are applied to cross-link hyaluronic acid polymers derivatised with a pendant bisphosphonate to generate hydrogels with enhanced mechanical properties and preserved protein binding able to sustain, for over six weeks in vivo, the localized activity of the clinically licensed growth factor BMP-2.
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| 4. |
- Kisiel, Marta, 1984-
(författare)
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Bone Enhancement with BMP-2 for Safe Clinical Translation
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bone morphogenetic protein-2 (BMP-2) is considered a promising adjuvant for the treatment of bone regeneration. However, BMP-2 delivery in a conventional collagen scaffold needs a high dose to achieve an effective outcome. Moreover, such dosage may lead to serious side effects. The aim of the following thesis was to find clinically acceptable strategies reducing the required dose of BMP-2 by improving the delivery and optimizing the preclinical testing of the new approaches. In all the studies hyaluronic acid (HA) hydrogels was used as a carrier for BMP-2.The HA hydrogel/BMP-2 construct was modified with bioactive matrix components in order to obtain an effective release of BMP-2 and an enhanced bone formation. The most promising were two strategies. In the first one, BMP-2, precomplexed with the glycosaminoglycans dermatan sulfate or heparin prior to loading it into HA hydrogel, protected and prolonged the delivery of the protein, resulting in twofold larger bone formation in comparison to non-complexed BMP-2. In the second strategy, the fibronectin fragment integrin-binding domain (FN) was covalently incorporated into HA hydrogel. The FN remarkably improved the capacity of the material to support the cells attachment and spreading, providing the formation of twice as much bone in comparison to non-functionalized HA hydrogel/BMP-2.Furthermore, the importance of a proper design of the preclinical study for BMP-2 delivery systems was highlighted. Firstly, proper physicochemical handling of BMP-2 showed the improvement in further in vivo activity. The use of glass storage vials and an acidic formulation buffer was superior to plastic surfaces and physiological pH. Secondly, while regenerative medicine strategy testing required the use of animal models that matched the research questions related to clinical translation, two new animal models were developed. The subperiosteal mandibular and calvarial models in rats were found to be minimally invasive, convenient and rapid solution for the evaluation of a broad range of approaches including bone augmentation, replacement and regeneration. Both models are primarily relevant for the initial testing of the injectable bone engineering constructs. Those clinically translatable approaches presented here could prove to be a powerful platform for a wider use of BMP-2 in orthopedic, plastic surgery and regenerative medicine research.
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| 5. |
- Peña Fernández, Marta, et al.
(författare)
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Exploratory Full-Field Strain Analysis of Regenerated Bone Tissue from Osteoinductive Biomaterials
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Biomaterials for bone regeneration are constantly under development, and their application in critical-sized defects represents a promising alternative to bone grafting techniques. However, the ability of all these materials to produce bone mechanically comparable with the native tissue remains unclear. This study aims to explore the full-field strain evolution in newly formed bone tissue produced in vivo by different osteoinductive strategies, including delivery systems for BMP-2 release. In situ high-resolution X-ray micro-computed tomography (microCT) and digital volume correlation (DVC) were used to qualitatively assess the micromechanics of regenerated bone tissue. Local strain in the tissue was evaluated in relation to the different bone morphometry and mineralization for specimens (n = 2 p/treatment) retrieved at a single time point (10 weeks in vivo). Results indicated a variety of load-transfer ability for the different treatments, highlighting the mechanical adaptation of bone structure in the early stages of bone healing. Although exploratory due to the limited sample size, the findings and analysis reported herein suggest how the combination of microCT and DVC can provide enhanced understanding of the micromechanics of newly formed bone produced in vivo, with the potential to inform further development of novel bone regeneration approaches.
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| 6. |
- Waddell, Shona J., et al.
(författare)
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Biomimetic oyster shell-replicated topography alters the behaviour of human skeletal stem cells
- 2018
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Ingår i: Journal of Tissue Engineering. - : Sage Publications. - 2041-7314. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The regenerative potential of skeletal stem cells provides an attractive prospect to generate bone tissue needed for musculoskeletal reparation. A central issue remains efficacious, controlled cell differentiation strategies to aid progression of cell therapies to the clinic. The nacre surface from Pinctada maxima shells is known to enhance bone formation. However, to date, there is a paucity of information on the role of the topography of P. maxima surfaces, nacre and prism. To investigate this, nacre and prism topographical features were replicated onto polycaprolactone and skeletal stem cell behaviour on the surfaces studied. Skeletal stem cells on nacre surfaces exhibited an increase in cell area, increase in expression of osteogenic markers ALP (p<0.05) and OCN (p<0.01) and increased metabolite intensity (p<0.05), indicating a role of nacre surface to induce osteogenic differentiation, while on prism surfaces, skeletal stem cells did not show alterations in cell area or osteogenic marker expression and a decrease in metabolite intensity (p<0.05), demonstrating a distinct role for the prism surface, with the potential to maintain the skeletal stem cell phenotype.
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| 7. |
- Xavier, Miguel, et al.
(författare)
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Label-free enrichment of primary human skeletal progenitor cells using deterministic lateral displacement
- 2019
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 19:3, s. 513-523
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Tidskriftsartikel (refereegranskat)abstract
- Skeletal stem cells (SSCs) are present in bone marrow (BM) and offer great potential for bone regenerative therapies. However, in the absence of a unique marker, current sorting approaches remain challenging in the quest for simple strategies to deliver SSCs with consistent regeneration and differentiation capacities. Microfluidics offers the possibility to sort cells marker-free, based on intrinsic biophysical properties. Recent studies indicate that SSCs are stiffer than leukocytes and are contained within the larger cell fraction in BM. This paper describes the use of deterministic lateral displacement (DLD) to sort SSCs based on cell size and stiffness. DLD is a technology that uses arrays of micropillars to sort cells based on their diameter. Cell deformation within the device can change the cell size and affect sorting - here evidenced using human cell lines and by fractionation of expanded SSCs. Following sorting, SSCs remained viable and retained their capacity to form clonogenic cultures (CFU-F), indicative of stem cell potential. Additionally, larger BM cells showed enhanced capacity to form CFU-F. These findings support the theory that SSCs are more abundant within the larger BM cell fraction and that DLD, or other size-based approaches, could be used to provide enriched SSC populations with significant implications for stem cell research and translation to the clinic.
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| 8. |
- Yan, Hongji, 1986-, et al.
(författare)
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Lithium hyaluronate hydrogels enhance osteogenesis in vitro and ex vivo
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Annan publikation (populärvet., debatt m.m.)abstract
- Lithium is a clinical drug for bipolar disorders and can enhance bone mass, promote osteogenesis of MSCs through inhibiting the Wnt/β-catenin signalling inhibitor GSK 3β. However, the systemic administration of lithium can trigger severe side-effects. Local administration has been attempted in the treatment of bone defects in animal models with positive outcomes. In this study, we explored a pre-manufactured hydrogel system containing the Li ion (Li-gel) in bone applications. Human MSCs cultured in this Li-gel exhibited enhanced osteogenic differentiation. Furthermore, this Li-gel was used to treat chick embryo chorioallantoic membrane (CAM) femur defects and enhanced the bone healing process.
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