Tissue Repair Technologies Limited

The action of MSF and its derivatives in wound healing

Transient Expression of MSF During Acute Wound Healing in Human Skin.  A. day 3: MSF production (shown by brown colour) is first apparent in the epithelial "tongue" migrating beneath the wound scab.  B. day 7: MSF is abundantly expressed by keratinocytes in the newly re-epithelised cell sheet and by fibroblasts and endothelial cells in the subjacent granulation tissue.  C. day 14: High levels of MSF expression throughout the epithelium and granulation tissue.  D. day 21 Undetectable or low levels of MSF expression throughout.

Induction of MSF Expression Induction of MSF Expression in a Healing Venous Stasis Ulcer. There is low or no detectable MSF expression in peri-lesional skin (A) and ulcer bed (B) at presentation. The ulcer was induced to heal by current best standard of care. Abundant MSF expression is apparent in a second biopsy of the healing ulcer (C) taken 28 days after therapy commenced.

The Effects of MSF  on Fibroblast Migration and Hyaluronan Synthesis The Effects of rhMSF (0.01pg/ml-100ng/ml) on Fibroblast Migration and Hyaluronan (HA) Synthesis. Cells were plated onto the surface of 3-dimensional native type I collagen gels in the absence or presence of the indicated concentration of MSF. After 4 days incubation, cell migration into the 3-dimensional collagen matrix and HA synthesis were ascertained. Control values are indicated by the dotted line (mean) and shaded area (standard deviation).

The Induction of Angiogenesis and Cell Migration into Subcutaneous grafts. MSF and IGDS were loaded to commercially available grafts used to promote wound healing (Permacol, Permaderm, Alloderm, SIS, Integra). The Figure shows collagenous grafts (Permacol) that had been soaked for 24hr in either PBS (control) or MSF (10ng/ml in PBS) and then implanted subcutaneously in rats. Skin biopsies containing the grafts were excised 28 days after implantation. Arrowheads mark the edge of the grafts. A. Control graft. Blood vessels (stained brown) and fibroblasts are principally confined to the host tissue surrounding the graft. B. MSF graft. Significantly more blood vessels and fibroblasts have infiltrated the graft.  The same results were obtained using IGDS-treated grafts (all types tested) and subcutaneous implantation in pigs.

The Induction of Angiogenesis in the Chick Yolk Sac The Induction of Angiogenesis in the Chick Yolk Sac. MSF and IGDS were incorporated into methyl cellulose gels (MCGs) and these applied to the chick embryo yolk sac membrane. A significant angiogenic response was induced over a broad concentration range (0.5-500ng/MCG) for both agents. PMA (300ng/MCG) was used as positive control.

Non-peptide IGD Mimetics. (left) Three dimensional structure of the seventh type I module of MSF/fibronectin backbone with space filling representation of the IGD motif. (right) Benzodiazepine core unit 1: First generation IGD peptidomimetic.

 The acceleration of wound healing in diabetic mice by MSF and IGDS. Mice received full thickness wounds on day 0 and were treated with PBS(control), MSF (0.2pg/dose) or IGDS (20pg/dose) once a day for 4 days. Figure shows representative examples of wounds on days 0 and 10 and the calculated wound area in mm2. The study included 8 mice per experimental group. Both MSF and IGDS significantly enhanced wound closure.

wound closure

The effects of TRT-8174 on wound healing were investigated in diabetic mice BKS.Cg-m Dock7m +/+ Leprdb /J (db/db), a model of delayed wound healing. A single standardised full-thickness wound (10.0mm x 10.0mm) was created in the dorsal skin of each animal and these were divided randomly into 4 groups of 8-10 animals each. TRT-8174 was applied in a gel (HPMC) at three different doses (20, 100 or 200 picograms per dose). The wounds received a single treatment of the appropriate dose on days 0, 2, 4 and 6 post-wounding (arrows). Controls received the gel alone at the same time. Image analysis software was used to calculate wound closure from images taken at regular intervals post-wounding. For each wound at each time point, open wound area was measured and expressed in terms of % wound area relative to day 0. Graphs show the mean and standard error for each group of animals. TRT-8174 significantly stimulated wound healing at the three doses tested. P values are shown for the 100 picogram dose. At this dose, the difference between controls and TRT-treated animals remained significant on day 20 (p=0.009), that is, 14 days after the last treatment with TRT-8174.

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