| 1. |
- Lazaridis, Iosif, et al.
(författare)
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Ancient human genomes suggest three ancestral populations for present-day Europeans
- 2014
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 513:7518, s. 409-
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Tidskriftsartikel (refereegranskat)abstract
- We sequenced the genomes of a similar to 7,000-year-old farmer from Germany and eight similar to 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes(1-4) with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians(3), who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had similar to 44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
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| 2. |
- Shanbhag, Siddharth, et al.
(författare)
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Efficacy of Humanized Mesenchymal Stem Cell Cultures for Bone Tissue Engineering : A Systematic Review with a Focus on Platelet Derivatives
- 2017
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Ingår i: Tissue engineering. Part B, Reviews. - : Mary Ann Liebert. - 1937-3368 .- 1937-3376. ; 23:6, s. 552-569
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Tidskriftsartikel (refereegranskat)abstract
- Fetal bovine serum (FBS) is the most commonly used supplement for ex vivo expansion of human mesenchymal stem cells (hMSCs) for bone tissue engineering applications. However, from a clinical standpoint, it is important to substitute animal-derived products according to current good manufacturing practice (cGMP) guidelines. Humanized alternatives to FBS include three categories of products: human serum (HS), human platelet derivatives (HPDs)-including platelet lysate (PL) or platelet releasate (PR), produced by freeze/thawing or chemical activation of platelet concentrates, respectively, and chemically defined media (serum-free) (CDM). In this systematic literature review, the in vitro and in vivo osteogenic potential of hMSCs expanded in humanized (HS-, HPD-, or CDM-supplemented) media versus hMSCs expanded in FBS-supplemented media, was compared. In addition, PL and PR were compared in terms of their growth factor (GF)/cytokine-content and cell-culture efficacy. When using either 10-20% autologous or pooled HS, 3-10% pooled HPDs or CDM supplemented with GFs, in comparison with 10-20% FBS, a majority of studies reported similar or superior in vitro proliferation and osteogenic differentiation, and in vivo bone formation in ectopic or orthotopic rodent models. Moreover, a trend for higher GF content was observed in PL versus PR, although evidence for cell culture efficacy is limited. In summary, humanized supplements seem at least equally effective as FBS for hMSC expansion and osteogenic differentiation. Although pooled HPDs appear to be the most favorable supplement for large-scale hMSC expansion, further efforts are needed to standardize the preparation and composition of these products in compliance with cGMP standards.
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| 3. |
- Shanbhag, Siddharth, et al.
(författare)
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Optimization of Human Platelet-Derived Supplements for Stem Cell-Based Bone Tissue Engineering
- 2017
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 28:S14, s. 57-57
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background Bone tissue engineering using combinations of adult mesenchymal stem cells (MSCs), growth factors and/or biomaterial scaffolds, is emerging as a promising alternative to autologous and allogeneic bone grafting. Although, fetal bovine serum (FBS) is still the most commonly used supplement for ex vivo expansion of human MSCs, it is important to substitute animal-derived products for clinical applications, according to current Good Manufacturing Practices (cGMP). Human platelet-derivatives (PDs) represent optimal FBS-substitutes due to the nature and range of the released growth factors (GF). Aim/Hypothesis (1) To systematically review the literature to identify different types of PDs, and (2) to refine the protocols for preparation of optimal platelet-derived supplements in terms of (a) GF concentrations, and (b) human MSC expansion and differentiation. The overall aim was to optimize the preparation of a cGMP-compliant platelet GF concentrate for large-scale MSC expansion. Material and Methods A systematic literature review was performed to compare the efficacy of different PDs. PDs were categorized as platelet ‘releasates’ (PR) or ‘lysates’ (PL) depending on the method of GF release, i.e. via chemical activation with thrombin (or calcium), or via mechanical lysis via freezing and thawing, respectively. Based on the review, selected protocols for preparation of PR and PL, using platelet concentrates pooled from 5 donors, were systematically tested and compared, in terms of (a) ELISA-based GF concentrations [platelet-derived growth factor (PDGF)-BB, transforming growth factor (TGF)- μ 946,1, and vascular endothelial growth factor (VEGF)], and (b) in vitro proliferation, colony-formation, surface marker expression (flow cytometry), and osteogenic differentiation assays of human gingiva-derived MSCs. Cells cultured in 10% FBS were used as the control. Experiments were performed in triplicates, using cells from three donors, and data were statistically analysed. Results A number of protocols were identified for preparation of PR and PL, varying in the nature and concentrations of activators (thrombin/calcium), and number and duration of freezing/thawing cycles, respectively. Few studies directly compared PR and PL, and a trend for superior cell proliferation with PL was observed. Based on the review, four different protocols were selected and adapted for preparation of PR and PL. For in vitro MSC experiments, PR/PL concentrations of 5% and 10% were tested. Consistent with results of the review, higher concentrations of GFs (PDGF-BB, TGF- μ 946,1, VEGF) were identified in PL vs. PR. Moreover, proliferation of MSCs was higher in PL vs. PR, in some donors, proliferation was higher in 5% PL vs. 10% PL, suggesting that 5% may be the optimal concentration when using this method of PL preparation. Comparable surface marker expression (stromal phenotype) was observed in MSCs expanded in PL vs. FBS. Significantly higher proliferation (population doubling-time) and colony-formation, and comparable osteogenic differentiation, of MSCs was observed in 5% PL vs. 10% FBS. Conclusions and Clinical Implications Human PL prepared from pooled platelet concentrates by a simple, economical and cGMP-compliant method, represents the optimal GF-supplement and FBS-substitute, while maintaining the key properties of MSCs, i.e., stromal phenotype, proliferation and osteogenic differentiation potential, for clinical bone tissue engineering applications.
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