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  • 1.
    Brohlin, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Biomedicinsk laboratorievetenskap.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Effects of a defined xeno-free medium on the growth and neurotrophic and angiogenic properties of human adult stem cells2017Ingår i: Cytotherapy, ISSN 1465-3249, E-ISSN 1477-2566, Vol. 19, nr 5, s. 629-639Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background. The growth properties and neurotrophic and angiogenic effects of human mesenchymal stromal cells (MSCs) cultured in a defined xeno-free, serum-free medium (MesenCult-XF) were investigated. Methods. Human MSCs from adipose tissue (ASCs) and bone marrow (BMSCs) were cultured in Minimum Essential Medium-alpha (alpha-MEM) containing fetal calf serum or in MesenCult-XF. Proliferation was measured over 10 passages and the colony-forming unit (CFU) assay and expression of cluster of differentiation (CD) surface markers were determined. Neurite outgrowth and angiogenic activity of the MSCs were determined. Results. At early passage, both ASCs and BMSCs showed better proliferation in MesenCult-XF compared with standard a-MEM containing serum. However, CFUs were significantly lower in MesenCult-XF. ASCs cultured in MesenCult-XF continued to expand at faster rates than cells grown in serum. BMSCs showed morphological changes at late passage in MesenCult-XF and stained positive for senescence beta-galactosidase activity. Expression levels of CD73 and CD90 were similar in both cell types under the various culture conditions but CD105 was significantly reduced at passage 10 in MesenCult-XF. In vitro stimulation of the cells enhanced the expression of brain derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF-A) and angiopoietin-1. Stimulated ASCs grown in MesenCult-XF evoked the longest neurite outgrowth in a neuron co-culture model. Stimulated BMSCs grown in MesenCult-XF produced the most extensive network of capillary-like tube structures in an in vitro angiogenesis assay. Conclusions. ASCs and BMSCs exhibit high levels of neurotrophic and angiogenic activity when grown in the defined serum free medium indicating their suitability for treatment of various neurological conditions. However, long-term expansion in MesenCult-XF might be restricted to ASCs.

  • 2.
    Chen, Jialin
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Zhang, Wei
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Backman, Ludvig J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Oftalmiatrik.
    Mechanical stress potentiates the differentiation of periodontal ligament stem cells into keratocytes2018Ingår i: British Journal of Ophthalmology, ISSN 0007-1161, E-ISSN 1468-2079, Vol. 102, nr 4, s. 562-569Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aims To explore the role of corneal-shaped static mechanical strain on the differentiation of human periodontal ligament stem cells (PDLSCs) into keratocytes and the possible synergistic effects of mechanics and inducing medium. Methods PDLSCs were exposed to 3% static dome-shaped mechanical strain in a Flexcell Tension System for 3 days and 7 days. Keratocyte phenotype was determined by gene expression of keratocyte markers. Keratocyte differentiation (inducing) medium was introduced in the Flexcell system, either continuously or intermittently combined with mechanical stimulation. The synergistic effects of mechanics and inducing medium on keratocyte differentiation was evaluated by gene and protein expression of keratocyte markers. Finally, a multilamellar cell sheet was assembled by seeding PDLSCs on a collagen membrane and inducing keratocyte differentiation. The transparency of the cell sheet was assessed, and typical markers of native human corneal stroma were evaluated by immunofluorescence staining. Results Dome-shaped mechanical stimulation promoted PDLSCs to differentiate into keratocytes, as shown by the upregulation of ALDH3A1, CD34, LUM, COL I and COL V. The expression of integrins were also upregulated after mechanical stimulation, including integrin alpha 1, alpha 2, beta 1 and non-muscle myosin II B. A synergistic effect of mechanics and inducing medium was found on keratocyte differentiation. The cell sheets were assembled under the treatment of mechanics and inducing medium simultaneously. The cell sheets were transparent, multilamellar and expressed typical markers of corneal stroma. Conclusion Dome-shaped mechanical stimulation promotes differentiation of PDLSCs into keratocytes and has synergistic effects with inducing medium. Multilamellar cell sheets that resemble native human corneal stroma show potential for future clinical applications.

  • 3.
    Chen, Jialin
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Zhang, Wei
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Backman, Ludvig J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi.
    Danielson, Patrik
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Oftalmiatrik.
    Substance P and patterned silk biomaterial stimulate periodontal ligament stem cells to form corneal stroma in a bioengineered three-dimensional model2017Ingår i: Stem Cell Research & Therapy, E-ISSN 1757-6512, Vol. 8, artikel-id 260Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: We aimed to generate a bioengineered multi-lamellar human corneal stroma tissue in vitro by differentiating periodontal ligament stem cells (PDLSCs) towards keratocytes on an aligned silk membrane.

    Methods: Human PDLSCs were isolated and identified. The neuropeptide substance P (SP) was added in keratocyte differentiation medium (KDM) to evaluate its effect on keratocyte differentiation of PDLSCs. PDLSCs were then seeded on patterned silk membrane and cultured with KDM and SP. Cell alignment was evaluated and the expression of extracellular matrix (ECM) components of corneal stroma was detected. Finally, multi-lamellar tissue was constructed in vitro by PDLSCs seeded on patterned silk membranes, which were stacked orthogonally and stimulated by KDM supplemented with SP for 18 days. Sections were prepared and subsequently stained with hematoxylin and eosin or antibodies for immunofluorescence observation of human corneal stroma-related proteins.

    Results: SP promoted the expression of corneal stroma-related collagens (collagen types I, III, V, and VI) during the differentiation induced by KDM. Patterned silk membrane guided cell alignment of PDLSCs, and important ECM components of the corneal stroma were shown to be deposited by the cells. The constructed multi-lamellar tissue was found to support cells growing between every two layers and expressing the main type of collagens (collagen types I and V) and proteoglycans (lumican and keratocan) of normal human corneal stroma.

    Conclusions: Multi-lamellar human corneal stroma-like tissue can be constructed successfully in vitro by PDLSCs seeded on orthogonally aligned, multi-layered silk membranes with SP supplementation, which shows potential for future corneal tissue engineering.

  • 4. Dinarello, Charles
    et al.
    Arend, William
    Sims, John
    Smith, Dirk
    Blumberg, Hal
    O'Neill, Luke
    Goldbach-Mansky, Raphaela
    Pizarro, Theresa
    Hoffman, H.
    Bufler, Philip
    Nold, Marcel
    Ghezzi, Pietro
    Mantovani, Alberto
    Garlanda, Cecilia
    Boraschi, Diana
    Rubartelli, Anna
    Netea, Mihai
    van der Meer, Jos
    Joosten, Leo
    Mandrup-Poulsen, Tom
    Donath, Marc
    Lewis, Eli
    Pfeilschifter, Josef
    Martin, Michael
    Kracht, Michael
    Muehl, H
    Novick, Daniela
    Lukic, Miodrag
    Conti, Bruno
    Solinger, Alan
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    van de Veerdonk, Frank
    Gabel, Chiristopher
    IL-1 family nomenclature2010Ingår i: Nature Immunology, ISSN 1529-2908, E-ISSN 1529-2916, Vol. 11, nr 11, s. 973-973Artikel i tidskrift (Refereegranskat)
  • 5.
    Höglund Åberg, Carola
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Aggregatibacter actinomycetemcomitans: virulence of its leukotoxin and association with aggressive periodontitis2015Ingår i: Virulence, ISSN 2150-5608, Vol. 6, nr 3, s. 188-195Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Periodontitis is an infection-induced inflammatory disease that causes loss of the tooth supporting tissues. Much focus has been put on comparison of the microbial biofilm in the healthy periodontium with the diseased one. The information arising from such studies is limited due to difficulties to compare the microbial composition in these two completely different ecological niches. A few longitudinal studies have contributed with information that makes it possible to predict which individuals who might have an increased risk of developing aggressive forms of periodontitis, and the predictors are either microbial or/and host-derived factors. The most conspicuous condition that is associated with disease risk is the presence of Aggregatibacter actinomycetemcomitans at the individual level. This Gram-negative bacterium has a great genetic variation with a number of virulence factors. In this review we focus in particular on the leukotoxin that, based on resent knowledge, might be one of the most important virulence factors of A. actinomycetemcomitans.

  • 6.
    Karalija, Amar
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    The effects of acetyl-­L-­carnitine treatment on neuroinflammation: An in vitro studyManuskript (preprint) (Övrigt vetenskapligt)
  • 7.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Abd, H
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Sandström, G
    Sjöstedt, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Cellular and molecular response of human macrophages exposed to Aggregatibacter actinomycetemcomitans leukotoxin.2011Ingår i: Cell death & disease, ISSN 2041-4889, Vol. 2, s. e126-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs to the repeats-in-toxin family, is believed to be one of its virulence factors and to have an important role in the bacterium's pathogenicity. This toxin selectively kills human leukocytes by inducing apoptosis and lysis. Here, we report that leukotoxin-induced cell death of macrophages proceeded through a process that differs from the classical characteristics of apoptosis and necrosis. A. actinomycetemcomitans leukotoxin-induced several cellular and molecular mechanisms in human macrophages that led to a specific and excessive pro-inflammatory response with particular secretion of both interleukin (IL)-1β and IL-18. In addition, this pro-inflammatory cell death was inhibited by oxidized ATP, which indicates involvement of the purinergic receptor P2X(7) in this process. This novel virulence mechanism of the leukotoxin may have an important role in the pathogenic potential of this bacterium and can be a target for future therapeutic agents.

  • 8.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Abd, Hadi
    Centre for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, Solna, Sweden.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Sandström, Gunnar
    Centre for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, Solna, Sweden ; Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institute, Stockholm, Sweden.
    Sjöstedt, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Inflammatory cell death of human macrophages in response to Aggregatibacter actinomycetemcomitans leukotoxinManuskript (Övrigt vetenskapligt)
    Abstract [en]

    Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs to the Repeats in Toxin (RTX) family, is believed to be one of its virulence factors and to play an important role in the bacterium's pathogenicity. This toxin selectively kills human leukocytes by inducing apoptosis and lysis. Here we report that leukotoxin-induced cell death of macrophages proceeded through a process that differs from the classical characteristics of apoptosis and necrosis. Interestingly, this process resembled pyroptosis, and resulted in an extensive leukotoxin-induced interleukin-1β (IL-1β) secretion. This activation was mainly mediated by caspase-1 activation, while the levels of mRNA for IL-1β were not affected by the leukotoxin. A similar pattern was seen for IL-18, but the level of that cytokine was about 30 times lower. Both of these cytokines are synthesized as biologically inactive precursors and need active caspase-1 for their activation and secretion. In conclusion, A. actinomycetemcomitans leukotoxin induces a pyroptosis-like cell death in human macrophages and that leads to a specific and excessive pro-inflammatory response. This novel virulence mechanism of the leukotoxin may play an important role in the pathogenic potential of this bacterium.

  • 9.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Chen, Casey
    Sjöstedt, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi. Parod.
    IL-1beta secretion induced by Aggregatibacter (Actinobacillus) actinomycetemcomitans is mainly caused by the leukotoxin2008Ingår i: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 298, nr 5/6, s. 529-541Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aggregatibacter (Actinobacillus) actinomycetemcomitans forms a leukotoxin that selectively lyses primate neutrophils, monocytes and triggers apoptosis in promyeloic cells and degranulation of human neutrophils. Recently, we showed that the leukotoxin causes activation of caspase-1 and abundant secretion of bio-active IL-1beta from human macrophages. In this study, we show that high levels of IL-beta correlated with a high proportion of A. actinomycetemcomitans in clinical samples from a patient with aggressive periodontitis. To determine the relative contribution of leukotoxin to the overall bacteria-induced IL-1beta secretion, macrophages were isolated from peripheral blood and exposed to different concentrations of live A. actinomycetemcomitans strains with either no, low or high production of leukotoxin. Cell lysis and levels of IL-1beta, IL-6, TNF-alpha and caspase-1 were measured by ELISA and flow cytometry. Leukotoxin was the predominant cause of IL-1beta secretion from macrophages, even in the A. actinomycetemcomitans strain with low leukotoxin production. Macrophages exposed to non-leukotoxic bacteria accumulated cytosolic pro-IL-1beta, which was secreted by a secondary exposure to leukotoxic bacteria. In conclusion, the present study shows for the first time that A. actinomycetemcomitans-induced IL-1beta secretion from human macrophages in vitro is mainly caused by leukotoxin.

  • 10.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hänström, L
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Kalfas, S
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Abundant secretion of bioactive interleukin-1beta by human macrophages induced by Actinobacillus actinomycetemcomitans leukotoxin2005Ingår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 73, nr 1, s. 453-458Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Actinobacillus actinomycetemcomitans produces a leukotoxin that selectively kills human leukocytes. Recently, we reported that macrophages are highly sensitive to leukotoxin and that their lysis involves activation of caspase 1. In this study, we show that leukotoxin also induces the production and release of proinflammatory cytokines from human macrophages. The macrophages were challenged with leukotoxin or lipopolysaccharide (LPS) from A. actinomycetemcomitans or LPS from Escherichia coli, and the production and secretion of interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) were determined at the mRNA and protein levels by reverse transcription-PCR and enzyme-linked immunosorbent assay, respectively. Leukotoxin (1 to 30 ng/ml) induced abundant production and secretion of IL-1beta, while the effects on IL-6 and TNF-alpha production were limited. Leukotoxin (1 ng/ml) caused a 10-times-higher release of IL-1beta than did LPS (100 ng/ml). The secreted IL-1beta was mainly the bioactive 17-kDa protein. At higher concentrations (>30 ng/ml), leukotoxin caused secretion of mainly inactive cytokine, the 31-kDa pro-IL-1beta. The presence of specific antibodies to IL-1beta or of a caspase 1 inhibitor blocked the secretion and production of the cytokine. Supernatants of leukotoxin-challenged macrophages stimulated bone resorption when tested in a mouse calvarial model. The activity could be blocked by an IL-1 receptor antagonist or specific antibodies to IL-1beta. We concluded that A. actinomycetemcomitans leukotoxin can trigger abundant production and secretion of bioactive IL-1beta by human macrophages, which is mediated by activation of caspase 1.

  • 11.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hänström, L
    Kalfas, S
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Caspase 1 involvement in human monocyte lysis induced by Actinobacillus actinomycetemcomitans leukotoxin2003Ingår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 71, nr 8, s. 4448-4455Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Actinobacillus actinomycetemcomitans, an oral bacterium implicated in the etiology of periodontal diseases, produces a leukotoxin that selectively lyses primate neutrophils and monocytes, the major populations of defense cells in the periodontium. Though lysis requires expression of the receptor lymphocyte function-associated molecule 1 (LFA-1) on the cell surface, not all LFA-1-expressing leukocyte populations are equally susceptible to the toxin. In this study, the susceptibility of human leukocytes to leukotoxin-induced lysis is compared to their expression of LFA-1 and the activity of caspase 1. Cytolysis was determined by the activity of lactate dehydrogenase released from peripheral human leukocytes after 1-h exposure to leukotoxin. Monocytes were lysed at leukotoxin concentrations of > or = 5 ng/ml, while the corresponding values for neutrophils and lymphocytes were approximately 10 times greater. Similar LFA-1 expression was found in all susceptible cell populations irrespective of their degree of sensitivity to the toxin. Exposure of monocytes to leukotoxin increased their caspase 1 activity about fivefold within 10 to 20 min. Presence of the caspase 1 inhibitor Ac-YVAD-CMK significantly blocked the leukotoxin-induced lysis of monocytes only. At sublytic concentrations, leukotoxin induced no apoptotic activity in monocytes, as revealed by the lack of caspase 3 activation and DNA fragmentation. Monocytes are the most lysis-sensitive leukocytes for A. actinomycetemcomitans leukotoxin. Their lysis by this toxin depends on caspase 1 activation and proceeds through a process that differs from classical apoptosis.

  • 12.
    Kolar, Mallappa Kadappa
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Itte, Vinay N.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Novikov, Lev N.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    The neurotrophic effects of different human dental mesenchymal stem cells2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 12605Artikel i tidskrift (Refereegranskat)
  • 13.
    Lauvrud, Anne Therese
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Characterization of human adipose tissue-derived stem cells with enhanced angiogenic and adipogenic properties2017Ingår i: Journal of Tissue Engineering and Regenerative Medicine, ISSN 1932-6254, E-ISSN 1932-7005, Vol. 11, nr 9, s. 2490-2502Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Autologous fat grafting is a popular method for soft tissue reconstructions but graft survival remains highly unpredictable. Supplementation of the graft with the stromal vascular fraction (SVF) or cultured adipose tissue-derived stem cells (ASCs) can enhance graft viability. In this study we have examined the phenotypic properties of a selected population of cells isolated from ASCs, with a view to determining their suitability for transplantation into grafts. ASCs were isolated from the SVF of human abdominal fat (n = 8 female patients) and CD146(+) cells were selected using immunomagnetic beads. The angiogenic and adipogenic properties of the positively selected cells were compared with the negative fraction. CD146(+) cells expressed the immunophenotypic characteristics of pericytes. With prolonged in vitro expansion, CD146(-) cells exhibited increased population doubling times and morphological signs of senescence, whereas CD146(+) cells did not. CD146(+) cells expressed higher levels of the angiogenic molecules VEGF-A, angiopoietin-1 and FGF-1. Conditioned medium taken from CD146(+) cells significantly increased formation of in vitro endothelial cell tube networks, whereas CD146(-) cells did not. CD146(+) cells could be differentiated into adipocytes in greater numbers than CD146(-) cells. Consistent with this, differentiated CD146(+) cells expressed higher levels of the adipocyte markers adiponectin and leptin. These results suggest that CD146(+) cells selected from a heterogeneous mix of ASCs have more favourable angiogenic and adipogenic properties, which might provide significant benefits for reconstructive and tissue-engineering applications. Copyright © 2016 John Wiley & Sons, Ltd.

  • 14.
    Pettersson, Linda F.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    In Vitro Osteogenic Differentiation of Human Mesenchymal Stem Cells from Jawbone Compared with Dental Tissue2017Ingår i: Tissue Engineering and Regenerative Medicine, ISSN 1738-2696, Vol. 14, nr 6, s. 763-774Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Autologous bone transplantation is the current gold standard for reconstruction of jawbone defects. Bone regeneration using mesenchymal stem cells (MSC) is an interesting alternative to improve the current techniques, which necessitate a second site of surgery resulting in donor site morbidity. In this study, we compared the osteogenic ability of jawbone MSC (JB-MSC) with MSC from tissues with neural crest origin, namely, the dental pulp, apical papilla and periodontal ligament. All four types of MSC were isolated from the same patient (n = 3 donors) to exclude inter-individual variations. The MSC growth and differentiation properties were characterized. The osteogenic differentiation potential in each group of cells was assessed quantitatively to determine if there were any differences between the cell types. All cells expressed the MSC-associated surface markers CD73, CD90, CD105, and CD146 and were negative for CD11b, CD19, CD34, CD45 and HLA-DR. All cell types proliferated at similar rates, exhibited similar clonogenic activity and could differentiate into adipocytes and osteoblasts. An alkaline phosphatase assay, OsteoImageTM assay for mineralization and qRT-PCR measuring the genes runx2, ALP and OCN, indicated that there were no significant differences in the osteogenic differentiation ability between the various MSCs. In conclusion, we show that from a small segment of jawbone it is possible to isolate sufficient quantities of MSC and that these cells can easily be expanded and differentiated into osteoblasts. JB-MSC appear to be good candidates for future bone regeneration applications in the craniofacial region.

  • 15.
    Pettersson, Mattias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Belibasakis, G. N.
    University of Zurich.
    Bylund, D.
    Mittuniversitetet Sundsvall.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Titanium ions form particles that activate and execute interleukin-1β release from lipopolysaccharide-primed macrophages2017Ingår i: Journal of Periodontal Research, ISSN 0022-3484, E-ISSN 1600-0765, Vol. 52, nr 1, s. 21-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND AND OBJECTIVE: Peri-implantitis is a destructive inflammatory process characterized by destruction of the implant-supporting bone. Inflammasomes are large intracellular multiprotein complexes that play a central role in innate immunity by activating the release of proinflammatory cytokines. Although inflammasome activation has previously been linked to periodontal inflammation, there is still no information on a potential association with peri-implantitis. The aim of this study was to examine cytotoxic and proinflammatory effects, including inflammasome activation, of metals used in dental implants, in an in vitro model, as well as from clinical tissue samples.

    MATERIAL AND METHODS: Human macrophages were exposed to different metals [titanium (Ti), cobalt, chromium and molybdenum] in a cell-culture assay. Cytotoxicity was determined using the neutral red uptake assay. Cytokine secretion was quantified using an ELISA, and the expression of genes of various inflammasome components was analysed using quantitative PCR. In addition, the concentrations of interleukin-1β (IL-1β) and Ti in mucosal tissue samples taken in the vicinity of dental implants were determined using ELISA and inductively coupled plasma mass spectrometry, respectively.

    RESULTS: Ti ions in physiological solutions stimulated inflammasome activation in human macrophages and consequently IL-1β release. This effect was further enhanced by macrophages that have been exposed to lipopolysaccharides. The proinflammatory activation caused by Ti ions disappeared after filtration (0.22 μm), which indicates an effect of particles. Ti ions alone did not stimulate transcription of the inflammasome components. The Ti levels of tissue samples obtained in the vicinity of Ti implants were sufficiently high (≥ 40 μm) to stimulate secretion of IL-1β from human macrophages in vitro.

    CONCLUSION: Ti ions form particles that act as secondary stimuli for a proinflammatory reaction.

  • 16.
    Qu, Chengjuan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Brohlin, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi. Division of Clinical Immunology and Transfusion Medicine, Tissue Establishment, Cell Therapy Unit, Department of Laboratory Medicine, Umeå University Hospital, Umeå, Sweden.
    Kingham, Paul J.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Evaluation of growth, stemness, and angiogenic properties of dental pulp stem cells cultured in cGMP xeno-/serum-free medium2019Ingår i: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study was aimed to investigate the effects of cGMP xeno-/serum-free medium (XSF, Irvine Scientific) on the properties of human dental pulp stem cells (DPSCs). DPSCs, from passage 2, were cultured in XSF or fetal bovine serum (FBS)-supplemented medium, and sub-cultured up to passage 8. Cumulative population doublings (PDs) and the number of colony-forming-units (CFUs) were determined. qRT-PCR, ELISA, and in vitro assays were used to assess angiogenic capacity. Flow cytometry was used to measure CD73, CD90, and CD105 expression. Differentiation into osteo-, adipo-, and chondrogenic cell lineages was performed. DPSCs showed more elongated morphology, a reduced rate of proliferation at later passages, and lower CFU counts in XSF compared with FBS. Expression of angiogenic factors at the gene and protein levels varied in the two media and with passage number, but cells grown in XSF had more in vitro angiogenic activity. The majority of early and late passage DPSCs cultured in XSF expressed CD73 and CD90. In contrast, the percentage of CD105 positive DPSCs in XSF medium was significantly lower with increased passage whereas the majority of cells cultured in FBS were CD105 positive. Switching XSF-cultured DPSCs to medium supplemented with human serum restored the expression of CD105. The tri-lineage differentiation of DPSCs cultured under XSF and FBS conditions was similar. We showed that despite reduced CD105 expression levels, DPSCs expanded in XSF medium maintained a functional MSC phenotype. Furthermore, restoration of CD105 expression is likely to occur upon in vivo transplantation, when cells are exposed to human serum.

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