J. T. Schantz

Technische Universität München, München, Bavaria, Germany

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Publications (13)29.14 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The commonly applied cell-based, two-dimensional (2D) in vitro resorption assays for biomaterials are limited in a variety of cases, including high initial roughness of material surface, uncontrollable solubilization (or resorption) of the entire material surface, or complex three-dimensional (3D) structure of the bioactive material itself. All these make the accurate assessment and successful selection of the optimal bone substitute material difficult. In vivo, micro-computed tomography (micro-CT) has been widely applied for the analysis of bone physiology and pathology, as well as for the 3D analysis of scaffolds for bone tissue engineering. In this study, we show that micro-CT can also be applied for the in vitro analysis of osteoclast-mediated resorption of biomaterials. For our experiments, we chose a calcium salt-composite (composite of calcium sulphate (CSC), calcium carbonate, glycerin-1,2,3-tripalmiate), which evades common 2D in vitro resorption analysis as a result of its high surface roughness and material composition. Human osteoclasts were differentiated from precursor cells on the surface of the material for 28 days. Cells were analyzed for expression of tartrate-resistant acid phosphatase 5b (TRAP5b), multinuclearity, and size. Volumetric analysis of resorption was performed by micro-CT. Multinucleated osteoclasts developed on the surface of the material. TRAP5b expression of the cells on CSC was comparable with TRAP5b expression of cells cultivated on dentin for the first 3 weeks of culture. At day 28, TRAP5b expression, cell number, and size of the TRAP+ cells were reduced on the CSC when compared with cells on dentin. Volumetric anaylsis by micro-CT showed a strong cellular effect on resorption of CSC. We consider micro-CT to be a promising technique for 3D quantification of cell-based resorption that will allow the study of cellular resorption of materials in vitro, which were up to now confined to animal experimental analysis.
    JOM: the journal of the Minerals, Metals & Materials Society 04/2014; 66(4):559-565. · 0.99 Impact Factor
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    ABSTRACT: Autologous fat grafting (lipofilling) from processed lipoaspirate is widely used to correct contour deformities and volume asymmetries after reconstructive surgery of the breast. Newer studies indicate that lipofilling of the breast is associated with low morbidity, an almost unaffected radiological follow-up and a predictable resorption rate. One currently assumes that active smoking and irradiation of the breast after Breast Conservative Treatment (BCT) respectively the skin and the thoracic wall after mastectomy decrease the engraftment rate of the fat due to impaired perfusion conditions and limited angiogenic response. The study aim was therefore to evaluate the resorption rate of the fat in healthy irradiated and non-irradiated patients as well as in smokers.
    IPRAS-Journal. 07/2013; 13:39-42.
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    ABSTRACT: Breast cancer is a major cause of illness for Australian women. Following tumour resection, breast reconstruction is undertaken for cosmetic and psychological reasons. Reconstruction using silicone-based implants leads to complications such as formation of a rigid fibrous tissue surrounding the implant giving a spherical and unnatural appearance to the breast. Reconstruction using autologous tissue is associated with donor site morbidity, tissue resorption and necrosis. Cell-based tissue engineering is an emerging approach to overcome these problems. Fully vascularised adipose tissue can be engineered in vivo with the help of patient-specific bioabsorbable implants fabricated by additive manufacturing. This chapter focuses on a review of such manufacturing techniques and the strategies being developed to engineer long-term fully vascularised and sustainable adipose tissue.
    01/2013: pages 183 - 216; , ISBN: 9781455728527
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    ABSTRACT: The clinical utilization of resorbable bone substitutes has been growing rapidly during the last decade, creating a rising demand for new resorbable biomaterials. An ideal resorbable bone substitute should not only function as a load-bearing material but also integrate into the local bone remodeling process. This means that these bone substitutes need to undergo controlled resorption and then be replaced by newly formed bone structures. Thus the assessment of resorbability is an important first step in predicting the in vivo clinical function of bone substitute biomaterials. Compared with in vivo assays, cell-based assays are relatively easy, reproducible, inexpensive and do not involve the suffering of animals. Moreover, the discovery of RANKL and M-CSF for osteoclastic differentiation has made the differentiation and cultivation of human osteoclasts possible and, as a result, human cell-based bone substitute resorption assays have been developed. In addition, the evolution of microscopy technology allows advanced analyses of the resorption pits on biomaterials. The aim of the current review is to give a concise update on in vitro cell-based resorption assays for analyzing bone substitute resorption. For this purpose models using different cells from different species are compared. Several popular two-dimensional and three-dimensional optical methods used for resorption assays are described. The limitations and advantages of the current ISO degradation assay in comparison with cell-based assays are discussed.
    Acta biomaterialia 01/2012; 8(1):13-9. · 5.09 Impact Factor
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    ABSTRACT: The drive to develop bone grafts for the filling of major gaps in the skeletal structure has led to a major research thrust towards developing biomaterials for bone engineering. Unfortunately, from a clinical perspective, the promise of bone tissue engineering which was so vibrant a decade ago has so far failed to deliver the anticipated results of becoming a routine therapeutic application in reconstructive surgery. Here we describe the analysis of long-term bone regeneration studies in preclinical animal models, exploiting methods of micro- and nano analysis of biodegradable composite scaffolds.
    Materials Today 01/2012; 15(10):430. · 6.07 Impact Factor
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    ABSTRACT: Adipose tissue engineering offers a promising alternative to the current surgical techniques for the treatment of soft tissue defects. It is a challenge to find the appropriate scaffold that not only represents a suitable environment for cells but also allows fabrication of customized tissue constructs, particularly in breast surgery. We investigated two different scaffolds for their potential use in adipose tissue regeneration. Sponge-like polyurethane scaffolds were prepared by mold casting with methylal as foaming agent, whereas polycaprolactone scaffolds with highly regular stacked-fiber architecture were fabricated with fused deposition modeling. Both scaffold types were seeded with human adipose tissue-derived precursor cells, cultured and implanted in nude mice using a femoral arteriovenous flow-through vessel loop for angiogenesis. In vitro, cells attached to both scaffolds and differentiated into adipocytes. In vivo, angiogenesis and adipose tissue formation were observed throughout both constructs after 2 and 4 weeks, with angiogenesis being comparable in seeded and unseeded constructs. Fibrous tissue formation and adipogenesis were more pronounced on polyurethane foam scaffolds than on polycaprolactone prototyped scaffolds. In conclusion, both scaffold designs can be effectively used for adipose tissue engineering.
    Cell and Tissue Research 08/2011; 347(3):747-57. · 3.68 Impact Factor
  • Handchirurgie Mikrochirurgie Plastische Chirurgie - HANDCHIR MIKROCHIR PLAST CHIR. 01/2010; 42(02).
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    ABSTRACT: The aim of this project was to investigate the in vitro osteogenic potential of human mesenchymal progenitor cells in novel matrix architectures built by means of a three-dimensional bioresorbable synthetic framework in combination with a hydrogel. Human mesenchymal progenitor cells (hMPCs) were isolated from a human bone marrow aspirate by gradient centrifugation. Before in vitro engineering of scaffold-hMPC constructs, the adipogenic and osteogenic differentiation potential was demonstrated by staining of neutral lipids and induction of bone-specific proteins, respectively. After expansion in monolayer cultures, the cells were enzymatically detached and then seeded in combination with a hydrogel into polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) frameworks. This scaffold design concept is characterized by novel matrix architecture, good mechanical properties, and slow degradation kinetics of the framework and a biomimetic milieu for cell delivery and proliferation. To induce osteogenic differentiation, the specimens were cultured in an osteogenic cell culture medium and were maintained in vitro for 6 weeks. Cellular distribution and viability within three-dimensional hMPC bone grafts were documented by scanning electron microscopy, cell metabolism assays, and confocal laser microscopy. Secretion of the osteogenic marker molecules type I procollagen and osteocalcin was analyzed by semiquantitative immunocytochemistry assays. Alkaline phosphatase activity was visualized by p-nitrophenyl phosphate substrate reaction. During osteogenic stimulation, hMPCs proliferated toward and onto the PCL and PCL-HA scaffold surfaces and metabolic activity increased, reaching a plateau by day 15. The temporal pattern of bone-related marker molecules produced by in vitro tissue-engineered scaffold-cell constructs revealed that hMPCs differentiated better within the biomimetic matrix architecture along the osteogenic lineage.
    Tissue Engineering 09/2003; 9(4):689-702. · 4.25 Impact Factor
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    ABSTRACT: The periodontal ligament (PDL) is believed to harbour cells with the capacity to regenerate the periodontium consisting of the PDL layer and surrounding alveolar bone and cementum. Fibroblast, the predominant cell type, is implicated in PDL tissue regeneration and repair. In this study, PDL fibroblasts (PDLF) from healthy human premolar and molar explants were cultured and characterized in vitro. Protein expression profiles were analysed and compared to gingival fibroblasts (GF) and alveolar bone osteoblasts (OB). Alkaline phosphatase (ALP) expression was higher in all induced cultures. Western blotting showed that all three cell types expressed osteonectin (ON) and osteopontin (OPN). Conversely, bone sialoprotein (BSP II) was down-regulated in PDLF and GF upon induction. Von Kossa staining revealed mineralised matrix for all induced cultures. This study showed the response of PDLF in protein expression, and pointed to its potential application in periodontal regeneration.
    Materials Science and Engineering C 01/2002; · 2.40 Impact Factor
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    ABSTRACT: A preliminary cell culture study of human keratinocytes (HK) on solvent-cast and biaxially stretched poly(ε-caprolactone) (PCL) films was carried out. Cell attachment and proliferation on solvent-cast films was compared with commercially available wound dressings while cell attachment, proliferation and viability on biaxially stretched films were assessed using light, confocal laser and scanning electron microscopy (CLM and SEM). Solvent-cast sheets were biaxially stretched to produce 5–15-μm-thick films. Biaxially stretched films were shown to be better epidermal substrates due to the better flexibility and strength to mass ratio than solvent-cast sheets. Images obtained showed that the cells attached and proliferated on poly(ε-caprolactone) films, and maintained high percentage of viability throughout the culture period. Keratinocytes exhibited healthy cobblestone morphology and proliferated as continuous monolayers. These results indicated that poly(ε-caprolactone) films would support the attachment and proliferation of human keratinocytes and have the potential to be applied as a matrix material for tissue engineering an epidermal equivalent.
    Materials Science and Engineering C 01/2002; 20:71-75. · 2.40 Impact Factor
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    ABSTRACT: The clinical goals for craniofacial skeletal reconstruction are multifaceted. Aesthetic and functional considerations often dictate the use of moldable implant materials. However, in most cases these three-dimensional shaped transplants must also provide immediate structural integrity. In addition, to minimize periimplant morbidity, the hostgraft interface should not produce an immunological or inflammatory response. Bone tissue engineering has emerged as a potential method to address the problems of autogenic bone grafting as well as allo- and xenoplastic materials. We report the three month results of a study in an immuno-competent model, the aim of which was to treat complex craniofacial defects.
    01/2002;
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    ABSTRACT: Various natural and synthetic polymeric materials have been used as scaffold matrices for tissue-engineered skin. However, the commercially available skin replacement products pose problems of poor mechanical properties and immunological rejection. We have thus developed a film of 5 microm thickness, via biaxial stretching of poly(epsilon-caprolactone) (PCL), as a potential matrix for living skin replacements. The aim of this study was to evaluate the feasibility of using biaxially stretched PCL films as matrices for culturing human dermal fibroblasts. For this purpose, we cultured human dermal fibroblasts for 7 days on the films. Glass cover slips and polyurethane (PU) sheets were used as controls. The data from phase contrast light, confocal laser, and scanning electron microscopy suggested that biaxially stretched PCL films support the attachment and proliferation of human dermal fibroblasts. Thymidine-labeling results showed quantitatively that cell proliferation on the PCL films was superior to that on the PU samples. These results indicated that biaxially stretched PCL films supported the growth of human dermal fibroblasts and might have potential to be applied in tissue engineering a dermal equivalent or skin graft.
    Tissue Engineering 09/2001; 7(4):441-55. · 4.25 Impact Factor
  • D. W. Hutmacher, X. Fu, B. K. Tan, J. T. Schantz
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    ABSTRACT: In this study, we compared three scaffold/cell constructs with different physical and chemical properties, in their potential for tissue engineering elastic cartilage. Group I consisted of PCL scaffolds Group II custom-made non-woven made of PGA fibers in combination with agarose beads; collagen sponges were used in-group III. Chondrocytes were isolated via enzyme digestion from an ear cartilage biopsy of 2 year old male piglets. 250,000 cells in 30 μl were seeded into three different scaffold types. The specimens were then cultured for 1 week. The scaffold/cell constructs and controls were placed subcutaneously on the paravertebral fascia for 4 1/2 month. Explanted scaffolds were cut in cubical blocks and mechanically tested in phosphate buffered saline solution at 37°C in accordance with ASTM F451-99a Standard Specification for Acrylic Bone Cement. After explantation the non-seeded PCL specimens (control) had compressive stiffness and 1 % offset yield strength in plane of 5.6 ± 0.4 MPa and out of plane 4.9 ± 0.5 MPa, respectively. In comparison, the scaffolds with a seeded specimens had compressive stiffness of 4.9 ± 0.5 MPa and 3.9± 0.3 MPa, respectively. The polymer molecular weight distribution was determined by gel permeation chromatography to study the in vivo degradation of the polymer matrix. Sections of expiants were prepared using standard cryohistochemical techniques and stained with anti-type II III, DC collagen antibodies, Factin and anti-integrin beta, and I. There was considerably more organized extracellular matrix formation in group I, whereas group II and III exhibiting a loosely scattered patterns. Results of the toluidine blue, trichrome Goldner’s staining and collagen II expression showed cartilage-like tissue formation in the PCL scaffolds whereas all the other matrices showed fibrous tissue in combination with calcification.

Publication Stats

166 Citations
29.14 Total Impact Points

Institutions

  • 2011–2014
    • Technische Universität München
      • Clinic and Polyclinic of Plastic Surgery and Hand Surgery
      München, Bavaria, Germany
  • 2003
    • Humboldt-Universität zu Berlin
      Berlín, Berlin, Germany
  • 2002
    • National University of Singapore
      • Department of Mechanical Engineering
      Singapore, Singapore