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Enhanced Large Animal Wound Healing with Amnion-based Therapeutics

Review of “Amnion Membrane Hydrogel and Amnion Membrane Powder Accelerate Wound Healing in a Full Thickness Porcine Skin Wound Model” from STEM CELLS Translational Medicine by Stuart P. Atkinson

The significant limitations associated with autologous split‐thickness skin grafts as a therapeutic approach to extensive burn and full-thickness skin wounds, including low availability of patient graft samples and the requirement for immunosuppressive drugs to avert immune rejection of allographs, have prompted the search for non-cellular dermal substitutes that can be easily incorporated into routine clinical use. A recent study from the laboratory of Sean V. Murphy (Wake Forest School of Medicine, Winston-Salem, NC, USA) described the development of a highly bioactive amnion hydrogel comprising a hyaluronic acid‐based hydrogel combined with solubilized amnion membrane that effectively healed wounds in a mouse model [1]. While the application of amnion membranes for wound healing and reconstructive purposes has a long history [2, 3], significant limitations related to handling, storing, and transporting amnion membrane sheets without significant degradation have only recently been “sidestepped” through the processing of amnion membranes into more straightforward to manage products.

Now, the team returns with a new STEM CELLS Translational Medicine article that reports on a comparative evaluation of wound‐healing efficacy of the amnion hydrogel, a less‐processed lyophilized amnion powder, and two commercially available wound healing products in a full-thickness porcine skin wound model [4]. Overall, the positive outcomes observed in this large animal model provide yet more evidence for the translational value of amnion hydrogel and amnion powder treatments for human wound treatment.

This fascinating study established significant and rapid wound healing driven by new epithelialization, rather than closure by contraction, following treatment with the amnion hydrogel and amnion powder. Furthermore, the amnion-based therapeutics accelerated wound closure and epithelialization and prevented contraction to a better degree than AmnioGraft (a cryopreserved amniotic membrane sheet) and Graftjacket (a decellularized human dermis graft [5]), thereby establishing the enhanced therapeutic potential of amnion-based wound healing approaches. The authors also noted the lack of immune cell infiltration and the ease of administration of the amnion-based products when compared to AmnioGraft and Graftjacket.

Subsequent detailed histological analyses also confirmed that the amnion-based products promoted the rapid healing of full‐thickness wounds and established the formation of a thick and mature epidermis and dermis with a similar composition to that observed in healthy skin. In comparison, AmnioGraft and Graftjacket led to a thinner epidermal covering that lacked dermal protrusions, suggestive of a slower rate of epidermal maturation. Histological staining also demonstrated that that amnion-based product-treated wounds possessed a dermal extracellular matrix composition consistent with mature skin. In contrast, AmnioGraft and Graftjacket-treated wounds presented with characteristics of hypertrophic scars.

As well as exploring the application of amnion-based wound healing products on other clinically relevant wound‐types, the authors hope to also explore the potential mechanisms of action of both the amnion hydrogel and powder. To this end, the authors note the probable requirement of extracellular matrix components and growth factors to promote keratinocyte proliferation and migration, neovascularization, and anti‐inflammatory effects.

To find out the future trajectory of this study and more on optimized amnion-based therapeutics for wound healing, stay tuned to the Stem Cells Portal!

 

References

  1. Murphy SV, Skardal A, Song L, et al., Solubilized Amnion Membrane Hyaluronic Acid Hydrogel Accelerates Full-Thickness Wound Healing. STEM CELLS Translational Medicine 2017;6:2020-2032.
  2. John T, Human amniotic membrane transplantation:: Past, present, and future. Ophthalmology Clinics 2003;16:43-65.
  3. Davis JS, Skin Transplantation. Johns Hopkins Hospital Reports 1910;15:307-96.
  4. Murphy SV, Skardal A, Nelson Jr RA, et al., Amnion membrane hydrogel and amnion membrane powder accelerate wound healing in a full thickness porcine skin wound model. STEM CELLS Translational Medicine 2020;9:80-92.
  5. Reyzelman A, Crews RT, Moore JC, et al., Clinical effectiveness of an acellular dermal regenerative tissue matrix compared to standard wound management in healing diabetic foot ulcers: a prospective, randomised, multicentre study. International Wound Journal 2009;6:196-208.