Following thermal injury, hypertrophic scar (HSc) is a frequent and severe form of fibrosis of the skin, which limits movement and compromises the cosmetic appearance and function of the skin. Prolonged pruritus and dysesthesia are also common problems in the previously injured, fibrotic tissues, as current understanding of the pathogenesis is limited, and few effective therapies exist, as with other fibroproliferative disorders (FPD). To investigate the role of T cells and their cytokines in the development of HSc, intracellular cytokine synthesis of circulating T cells was measured serially in burn patients using flow cytometry from the time of injury to over a 1-year period during which many patients developed HSc. Within 1 month of injury, low interferon-gamma (IFN-gamma)-positive T cells (Th1) were found in association with low interleukin-12 (IL-12) and absent IFN-gamma cytokine levels in the serum. IL-4-positive Th 2 cells, however, were significantly increased compared with normal controls by 2 months postinjury. In burn patients with HSc, serum IL-10 and transforming growth factor-beta (TGF-beta) levels were also significantly increased early after burn injury in patients who later developed HSc compared with normal volunteers and with a subset of burn patients who did not develop HSc, before returning to normal levels after 6 months. Activated peripheral blood mononuclear cells (PBMC) demonstrated that mRNA for IFN-gamma was present only in normal volunteers or patients without HSc but was undetectable in HSc patients. IL-4 mRNA levels were increased in the PBMCs of burn patients with HSc. In HSc tissues, IL-4 mRNA was increased, whereas, IFN-gamma mRNA was reduced compared with normal skin and mature scar. Increased CD3(+) and CD4(+) cells were present in HSc tissues compared with normal skin and were coexpressed with the fibrogenic cytokine TGF-beta. These longitudinal studies in human patients with HSc suggest that fibrosis in the skin is associated with a polarized Th2 systemic response to injury that leads to increased T cells and their Th2 fibrogenic cytokines in tissues and the development of fibrosis and HSc.

Journal Article Polarized Th2 / Th3 Cytokines in Hypertropic Scar Following Thermal Injury Get access E. E. Tredget, MD, FRCSC, E. E. Tredget, MD, FRCSC 1University of Alberta, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar J Wang, MD, PhD, J Wang, MD, PhD 1University of Alberta, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar H Shankowsky, RN, H Shankowsky, RN 1University of Alberta, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar L Yang, PhD, L Yang, PhD 1University of Alberta, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar P. G. Scott, PhD P. G. Scott, PhD 1University of Alberta, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar Journal of Burn Care & Research, Volume 27, Issue suppl_2, March 2006, Page S110, https://doi.org/10.1097/01253092-200603001-00123 Published: 01 March 2006

Journal Article The Identification and Quantification of Cutaneous Fibrocytes in Burn Patients Get access L. Yang, PhD, L. Yang, PhD 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar J. Giuffre, BSc, J. Giuffre, BSc 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar C. Dodd, RRT, C. Dodd, RRT 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar H. Shankowsky, RN, H. Shankowsky, RN 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar P. Scott, PhD, P. Scott, PhD 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar E. Tredget, MD, FRCS E. Tredget, MD, FRCS 1University of Alberta Hospital, Edmonton, AB, Canada Search for other works by this author on: Oxford Academic Google Scholar The Journal of Burn Care & Rehabilitation, Volume 24, Issue suppl_2, March-April 2003, Page S74, https://doi.org/10.1097/00004630-200303002-00064 Published: 01 March 2003

Despite the growing use of titanium as an implant material, there is a lack of consensus on what constitutes the molecular basis of its biocompatibility. In the present study we compared the response of skin fibroblasts to two different growth supporting surfaces: commercially pure titanium (cpTi) and tissue culture polystyrene (TCPS). Proteins from extracts of whole cells and adsorbed serum were separated and identified by 2-dimensional gel electrophoresis. In all, 40 proteins (46 spots) were identified by matrix-assisted laser desorption/ionization and mass spectrometry, database searching, immunoblotting, running a standard, or a combination of these techniques. Many of the proteins collected from the two surfaces were found to derive from the serum used in the culture medium. The surface properties of titanium appeared to promote the formation of a more concentrated carpet of serum proteins. Several proteins from bovine or human serum, such as albumin, alpha2-HS-glycoprotein, alpha-fetoprotein, plasminogen, thrombospondin 1, and serotransferrin, along with a few unidentified serum components, were found to adsorb onto cpTi in comparatively high concentrations. The adsorption of serum proteins did not appear to be selective on either substrate. We found that among the major cellular proteins, fibronectin and a cytoskeletal protein (non-muscle myosin heavy chain type A) were expressed at lower levels by fibroblasts grown on cpTi compared to TCPS. By analyzing the changes in the entire proteome of cells in response to different growth substrates, we may gain a better understanding of the molecular basis of biocompatibility.

Normal human skin fibroblasts were cultured on tissue culture polystyrene and on commercially pure titanium. In addition, substrate-attached material that remained on the surfaces after detachment of fibroblasts with a chelating agent was examined. The force required to detach 50% of the fibroblasts from each substrate was assessed by centrifugation. The results showed a time-dependent decrease in the force required to detach fibroblasts from titanium not seen on tissue culture polystyrene. Nearly all cells detached from the titanium surfaces at 7.85 × 10×3 dynes/cell after 3 or 5 days in culture, whereas few cells detached from tissue culture polystyrene. Cells freshly seeded onto titanium substrates that had been coated with substrate-attached material by prior culture of fibroblasts for 3 or 5 days showed an approximately sixfold increased adherence. The results of immunofluorescence staining for fibronectin and its receptor suggest that the nature of the interaction between this extracellular matrix ligand and the substrate may be important in determining cellular stiffness at the cell–extracellular matrix interface. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 52, 315–322, 2000.

To analyse regional variations in extracellular matrix components of adult rat temporomandibular joint discs, immunohistochemical techniques were used to examine the localization of two small dermatan-sulphate proteoglycans, biglycan and decorin, and a large chondroitin-sulphate proteoglycan. Staining for biglycan was intense in the posterior band, although it had a rather weak and even distribution throughout the disc. In contrast, staining for decorin was faint in the intermediate zone and the central part of the posterior band, moderate in the anterior and posterior attachments and most intense in the junction between the anterior band and attachment. The upper surface of the disc stained more intensely than the lower. Similarly, there was intense staining for large chondroitin-sulphate proteoglycan in the peripheral band, but both the anterior and the temporal parts of the posterior attachments were faintly stained. These results demonstrate marked regional differences in the expression of biglycan, decorin and large chondroitin-sulphate proteoglycan in the temporomandibular joint discs of adult rats. These variations probably reflect the different biomechanical environments caused by the complicated articulatory functions of the temporomandibular joint.

Tredget, E; Shankowsky, H.; Shen, Y; Nedelec, B; Dodd, C; Scott, P; Ghaharv, A Author Information

An endopeptidase which digests denatured collagen to small, dialysable fragments was purified 2675-fold from medium that had been conditioned by the culture of fibroblasts grown from explants of human gingiva. This enzyme was inhibited by chelating agents, but not by phenylmethylsulphonyl fluoride nor by N-ethylmaleimide, and is therefore probably a metalloproteinase. It showed no demonstrable activity against native collagen or ovalbumin, while alpha-casein was digested slowly, if at all. It therefore belongs to the group of enzymes which have been called tissue gelatinases. This gelatinase was secreted in a latent form or forms and could be activated by proteolysis with trypsin. The active enzyme had an apparent molecular weight of 69 000 (gel chromatography) or 72 000 (gel electrophoresis in sodium dodecyl sulphate) and an apparent isoelectric point of 4.15.

Deglycosylation of bovine skin proteodermatan sulfate with chondroitinase ABC yielded a protein core with an apparent molecular weight of about 45,000. The amino acid sequence of this preparation was determined up to position 24. This region was enriched in acidic amino acids and proline compared with the whole protein core and it was predicted to be highly folded. The amino acid sequence determined in these experiments has a gap at position 4. Results obtained after beta-elimination-sulfite addition showed that residue 4 was an O-substituted hydroxyamino acid. The latter was identified as serine by sequencing the NH2-terminal region of the protein core (Mr approximately 43,000) isolated after a more complete deglycosylation of the proteoglycan with anhydrous HF. Serine 4 may be an attachment site for one of the few dermatan sulfate chains present in the proteoglycan.